Methods for determining the total biochemical activity of soil microflora

Characteristics of microbes of cellular organization

The role of microorganisms in nature and agriculture

The wide distribution of microorganisms indicates their enormous role in nature. With their participation, the decomposition of various organic substances in soils and water bodies occurs, they determine the circulation of substances and energy in nature; soil fertility, the formation of coal, oil, and many other minerals depend on their activity. Microorganisms are involved in rock weathering and other natural processes.

Many microorganisms are used in industrial and agricultural production. Thus, baking, the manufacture of fermented milk products, winemaking, the production of vitamins, enzymes, food and feed proteins, organic acids, and many substances used in agriculture, industry, and medicine are based on the activity of various microorganisms. The use of microorganisms in crop production and animal husbandry is especially important. The enrichment of the soil with nitrogen, the control of pests of agricultural crops with the help of microbial preparations, the proper preparation and storage of feed, the creation of feed protein, antibiotics and microbial substances for animal feed depend on them.

Microorganisms have a positive effect on the processes of decomposition of substances of non-natural origin - xenobiotics, artificially synthesized, falling into soils and water bodies and polluting them.

Along with beneficial microorganisms, there is a large group of so-called disease-causing, or pathogenic, microorganisms that cause various diseases of agricultural animals, plants, insects and humans. As a result of their vital activity, epidemics of contagious diseases of humans and animals arise, which affects the development of the economy and the productive forces of society.

The latest scientific data not only significantly expanded the understanding of soil microorganisms and the processes they cause in the environment, but also made it possible to create new industries in industry and agricultural production. For example, antibiotics secreted by soil microorganisms have been discovered, and the possibility of their use for the treatment of humans, animals and plants, as well as for the storage of agricultural products, has been shown. The ability of soil microorganisms to form biologically active substances was discovered: vitamins, amino acids, plant growth stimulants - growth substances, etc. Ways have been found to use the protein of microorganisms for feeding farm animals. Microbial preparations have been identified that enhance the flow of nitrogen into the soil from the air.

The discovery of new methods for obtaining hereditarily modified forms of beneficial microorganisms has made it possible to use microorganisms more widely in agricultural and industrial production, as well as in medicine. The development of gene or genetic engineering is especially promising. Its achievements ensured the development of biotechnology, the emergence of highly productive microorganisms synthesizing proteins, enzymes, vitamins, antibiotics, growth substances and other products necessary for animal husbandry and crop production.

Humanity has always been in contact with microorganisms, for millennia without even knowing it. Since time immemorial, people have observed dough fermentation, prepared alcoholic beverages, fermented milk, made cheese, suffered various diseases, including epidemic ones. Evidence of the latter in the biblical books is an indication of an epidemic disease (probably a plague) with recommendations to burn corpses and perform ablutions.

In accordance with the currently accepted classification of microorganisms, according to the type of nutrition, they are divided into a number of groups depending on the sources of energy and carbon consumption. So, there are phototrophs that use the energy of sunlight, and chemotrophs, the energy material for which is a variety of organic and inorganic substances.

Depending on the form in which microorganisms obtain carbon from the environment, they are divided into two groups: autotrophic ("self-feeding"), using carbon dioxide as the only source of carbon, and heterotrophic ("feeding at the expense of others"), receiving carbon in the composition of rather complex reduced organic compounds.

Thus, according to the method of obtaining energy and carbon, microorganisms can be divided into photoautotrophs, photoheterotrophs, chemoautotrophs and chemoheterotrophs. Within the group, depending on the nature of the oxidizable substrate, called an electron donor (H-donor), in turn, there are organotrophs that consume energy during the decomposition of organic substances, and lithotrophs (from the Greek lithos - stone), which receive energy due to the oxidation of inorganic substances . Therefore, depending on the energy source and electron donor used by microorganisms, one should distinguish between photoorganotrophs, photolithotrophs, chemoorganotrophs, and chemolithotrophs. Thus, there are eight possible types of food.

Each group of microorganisms has a specific type of nutrition. Below is a description of the most common types of nutrition and a brief list of microorganisms that carry them out.

In phototrophy, the source of energy is sunlight. Photolithoautotrophy is a type of nutrition characteristic of microorganisms that use light energy to synthesize cell substances from CO 2 and inorganic compounds (H 2 0, H 2 S, S °), i.e. carrying out photosynthesis. This group includes cyanobacteria, purple sulfur bacteria and green sulfur bacteria.

Cyanobacteria (Cyanobacteria1es order), like green plants, reduce CO 2 to organic matter by photochemical means using the hydrogen of water:

C0 2 + H 2 0 light-› (CH 2 O) * + O 2

Purple sulfur bacteria (family Chromatiaceae) contain bacteriochlorophylls a and b, which determine the ability of these microorganisms to photosynthesize, and various carotenoid pigments.

To restore CO 2 to organic matter, bacteria of this group use hydrogen, which is part of H 2 5. At the same time, sulfur granules accumulate in the cytoplasm, which is then oxidized to sulfuric acid:

C0 2 + 2H 2 S light-› (CH 2 O) + H 2 + 2S

3CO 2 + 2S + 5H 2 O light-> 3 (CH 2 0) + 2H 2 S0 4

Purple sulfur bacteria are usually obligate anaerobes.

Green sulfur bacteria (family Chlorobiaceae) contain green bacteriochlorophylls with and, in a small amount of bacteriochlorophyll, as well as various carotenoids. Like purple sulfur bacteria, they are strict anaerobes and are capable of oxidizing hydrogen sulfide, sulfides and sulfites in the process of photosynthesis, accumulating sulfur, which in most cases is oxidized to 50^" 2.

Photoorganoheterotrophy is a type of nutrition characteristic of microorganisms that, in addition to photosynthesis, can also use simple organic compounds to obtain energy. Purple non-sulfur bacteria belong to this group.

Purple non-sulfur bacteria (family Rhjdospirillaceae) contain bacteriochlorophylls a and b, as well as various carotenoids. They are not able to oxidize hydrogen sulfide (H 2 S), accumulate sulfur and release it into the environment.

In chemotrophy, the energy source is inorganic and organic compounds. Chemolithoautotrophy is a type of nutrition characteristic of microorganisms that obtain energy from the oxidation of inorganic compounds, such as H 2, NH 4 +, N0 2 -, Fe 2+, H 2 S, S °, S0z 2 -, S 2 0z 2- , CO, etc. The oxidation process itself is called chemosynthesis. Carbon for the construction of all components of chemolithoautotrophic cells is obtained from carbon dioxide.

Chemosynthesis in microorganisms (iron bacteria and nitrifying bacteria) was discovered in 1887-1890. famous Russian microbiologist S.N. Vinogradsky. Chemolithoautotrophy is carried out by nitrifying bacteria (oxidize ammonia or nitrite), sulfur bacteria (oxidize hydrogen sulfide, elemental sulfur, and some simple inorganic sulfur compounds), bacteria that oxidize hydrogen to water, iron bacteria that can oxidize ferrous compounds, etc.

An idea of ​​the amount of energy obtained during the processes of chemolithoautotrophy caused by these bacteria is given by the following reactions:

NH3 + 11/2 0 2 - HN0 2 + H 2 0 + 2.8 10 5 J

HN0 2 + 1/2 0 2 - HN0 3 + 0.7 105 J

H 2 S + 1/2 0 2 - S + H 2 0 + 1.7 10 5 J

S + 11/2 0 2 - H 2 S0 4 + 5.0 10 5 J

H 2 + 1/ 2 0 2 - H 2 0 + 2.3 10 5 J

2FeС0 3 + 1/2 0 2 + ZN 2 0 - 2Fe (OH) 3 + 2С0 2 + 1.7 10 5 J

Chemoorganoheterotrophy is a type of nutrition characteristic of microorganisms that obtain the necessary energy and carbon from organic compounds. Among these microorganisms are many aerobic and anaerobic species that live in soils and other substrates.

Practical use of bacteria in food production

Among bacteria, lactic acid bacteria of the genera Lactobacillus, Streptococcus in the production of dairy products. Cocci have a round, oval shape with a diameter of 0.5-1.5 microns, arranged in pairs or chains of different lengths. The sizes of rod-shaped bacteria or combined into chains.

Lactic acid streptococcus Streptococcus lactis has cells connected in pairs or short chains, coagulates milk after 10-12 hours, some races form the antibiotic nisin.

C 6 H 12 O 6 → 2CH 3 CHOHCOOH

Creamy Streptococcus S. cremoris forms long chains from spherical cells, an inactive acid-forming agent, is used in the fermentation of cream in the production of sour cream.

acidophilus bacillus lactobacillus acidophilus form long chains of rod-shaped cells; during fermentation, it accumulates up to 2.2% lactic acid and antibiotic substances that are active against pathogens of intestinal diseases. Based on them, medical biological preparations are prepared for the prevention and treatment gastrointestinal diseases agricultural animals.

Lactic acid sticks L. plantatum have cells linked in pairs or in chains. Causative agents of fermentation during fermentation of vegetables and silage of fodder. L. brevis ferment sugars during sauerkraut, cucumbers, forming acids, ethanol, CO 2.

Non-sporing, non-motile, gram+ rods of the genus Propionibacterium families Propionibacteriaceae- causative agents of propionic acid fermentation, cause the conversion of sugar or lactic acid and its salts into propionic and acetic acid.

3C 6 H 12 O 6 → 4CH 3 CH 2 COOH + 2CH 3 COOH + 2CO 2 + 2H 2 O

Propionic acid fermentation underlies the maturation of rennet cheeses. Some types of propionic acid bacteria are used to produce vitamin B 12 .

spore-forming bacteria of the family Bacilloceae kind Clostridium are causative agents of butyric fermentation, converting sugars into butyric acid

C 6 H 12 O 6 → CH 3 (CH 2) COOH + 2CO 2 + 2H 2

Butyric acid

habitats- soil, silt deposits of reservoirs, accumulations of decaying organic residues, food products.

These m / o are used in the production of butyric acid, which has an unpleasant odor, in contrast to its esters:

Methyl ether - apple smell;

Ethyl - pear;

Amyl - pineapple.

They are used as flavorings.

Butyric acid bacteria can cause spoilage of food raw materials and products: swelling of cheeses, rancidity of milk, butter, bombing of canned food, death of potatoes and vegetables. The resulting butyric acid gives a sharp rancid taste, a sharp unpleasant odor.

Acetic acid bacteria - non-sporing Gram-rods with polar flagella, belong to the genus Gluconobacter (Acetomonas); form acetic acid from ethanol

CH 3 CH 2 OH+O 2 →CH 3 COOH+H 2 O

Rods of the Kind Acetobacter- peritrichous, capable of oxidizing acetic acid to CO 2 and H 2 O.

Acetic acid bacteria are characterized by variability in shape; under unfavorable conditions, they take the form of thick long filaments, sometimes swollen. Acetic acid bacteria are widely distributed on the surface of plants, their fruits, and in pickled vegetables.

The process of oxidizing ethanol to acetic acid underlies the production of vinegar. Spontaneous development of acetic acid bacteria in wine, beer, kvass leads to their deterioration - souring, turbidity. These bacteria on the surface of liquids form dry wrinkled films, islands or a ring near the walls of the vessel.

Common type of damage putrefaction is the process of deep decomposition of protein substances by microorganisms. The most active causative agents of putrefactive processes are bacteria.

Hay and potato stickBacillus subtilis - aerobic gram + spore-forming bacillus. Spores heat-resistant oval. Cells are sensitive to acidic environment and elevated NaCl content.

Bacteria of the genusPseudomonus - aerobic motile rods with polar flagella, do not form spores, gram-. Some species synthesize pigments, they are called fluorescent pseudomonas, there are cold-resistant ones, they cause spoilage of protein products in refrigerators. Causative agents of bacterioses of cultivated plants.

Spore-forming rods of the genus Clostridium decompose proteins with the formation of a large amount of gas NH 3, H 2 S, acids, especially dangerous for canned food. Severe food poisoning is caused by the toxin of large mobile gram+ sticks. Clostridium botulinum. Spores give the appearance of a racket. The exotoxin of these bacteria affects the central nervous and cardiovascular systems (signs - visual impairment, speech, paralysis, respiratory failure).

Great importance nitrifying, denitrifying, nitrogen-fixing bacteria play in soil formation. Basically, these are non-spore-forming cells. They are grown in artificial conditions and applied in the form of fertilizer preparations.

Bacteria are used in the production of hydrolytic enzymes, amino acids for food production.

Among bacteria, it is especially necessary to highlight the causative agents of food infections and food poisoning.. Food infections are caused by pathogenic bacteria present in food and water. Intestinal infections - cholera - cholera virion;

Everyone knows that bacteria are the most ancient inhabitants of the planet Earth. They appeared, according to scientific data, from three to four billion years ago. And for a long time were the sole and full owners of the Earth. We can say that it all started with bacteria. Roughly speaking, the genealogy of all is from them. So the role of bacteria in human life and nature (its formation) is very significant.

Ode to bacteria

Their structure is very primitive - for the most part they are unicellular organisms, which, obviously, have changed little over such a very long time. They are unpretentious and can survive in extreme conditions for other organisms (heating up to 90 degrees, freezing, a rarefied atmosphere, the deepest ocean). They live everywhere - in water, soil, underground, in the air, inside other living organisms. And in one gram of soil, for example, hundreds of millions of bacteria can be found. Truly almost ideal creatures that exist next to us. The role of bacteria in human life and nature is great.

Creators of oxygen

Did you know that, most likely, without the existence of these small organisms, we would simply suffocate? Because they (mainly cyanobacteria, capable of releasing oxygen as a result of photosynthesis), due to their abundance, produce a huge amount of oxygen entering the atmosphere. This becomes especially relevant in connection with the deforestation of strategically important forests for the entire Earth. And some other bacteria release carbon dioxide, which is essential for plant respiration. But the role of bacteria in human life and nature is not limited to this. There are several more "activities" for which bacteria can be safely given

Orderlies

In nature, one of the functions of bacteria is sanitary. They eat dead cells and organisms, utilizing the unnecessary. It turns out that bacteria for all living things on the planet work as a kind of janitors. In science, this phenomenon is called saprotrophy.

Circulation of substances

And another important role is participation in a planetary scale. In nature, all substances pass from organism to organism. Sometimes they are in the atmosphere, sometimes in the soil, maintaining a large-scale cycle. Without bacteria, these ingredients could be concentrated somewhere in one place, and the great cycles would be interrupted. This happens, for example, with a substance such as nitrogen.

Lactic acid products

Milk - for a long time known to people product. But its long-term storage became possible only in recent times with the invention of conservation methods and refrigeration. And since the dawn of cattle breeding, man has unknowingly used bacteria to ferment milk and produce fermented milk products with a longer shelf life than milk itself. So, for example, dry kefir could be stored for months and used as a hearty meal during long transitions through desert areas. In this regard, the role of bacteria in human life is invaluable. After all, if these organisms are “offered” milk, they will be able to produce a lot of tasty and irreplaceable food products from it. Among them: yogurt, curdled milk, fermented baked milk, sour cream, cottage cheese, cheese. Kefir, of course, is made mainly by fungi, but it can’t do without the participation of bacteria.

Great chefs

But the "food-forming" role of bacteria in human life is not limited to fermented milk products. There are many more familiar to us products that are produced with the help of these organisms. it sauerkraut, salted (barrel) cucumbers, pickles loved by many and other products.

The best neighbors in the world

Bacteria is the most numerous kingdom of animal organisms in nature. They live everywhere - around us, on us, even - inside us! And they are very useful "neighbors" for a person. So, for example, bifidobacteria strengthen our immunity, increase the body's resistance to many diseases, help digestion and do a lot of other necessary things. Thus, the role of bacteria in human life as good "neighbors" is just as invaluable.

Production of the necessary substances

Scientists were able to work with bacteria in such a way that as a result they began to secrete substances that are necessary for humans. Often these substances are drugs. So the therapeutic role of bacteria in human life is also great. Some modern medicines are made by them or based on their action.

The role of bacteria in industry

Bacteria are great biochemists! This property is widely used in modern industry. So, for example, in recent decades, biogas production in some countries has reached serious proportions.

Negative and positive role of bacteria

But these microscopic unicellular organisms can be not only helpers of a person and coexist with him in complete harmony and peace. The biggest danger that they are fraught with is infectious. Settling inside us, poisoning the tissues of our body, they are certainly harmful, sometimes fatal to humans. Among the most famous dangerous diseases caused by bacteria are plague, cholera. Less dangerous are angina and pneumonia, for example. Thus, some bacteria can pose a significant danger to humans if they are pathogenic. Therefore, scientists and doctors of all times and peoples are trying to "keep under control" these harmful microorganisms.

Food spoilage by bacteria

If the meat is rotten, and the soup is sour, for sure, this is the “handiwork” of bacteria! They start up there and actually "eat" these products before us. After that, for a person, these dishes no longer represent nutritional value. It remains only to throw away!

Results

When answering the question of what role bacteria play in human life, both positive and negative points can be distinguished. However, it is obvious that the positive properties of bacteria are much greater than the negative ones. It's all about the reasonable control of man over this numerous kingdom.

Introduction

Modern biotechnology is based on the achievements of natural science, engineering, technology, biochemistry, microbiology, molecular biology, and genetics. Biological methods are used in the fight against environmental pollution and pests of plant and animal organisms. The achievements of biotechnology can also include the use of immobilized enzymes, the production of synthetic vaccines, the use of cell technology in breeding.

Bacteria, fungi, algae, lichens, viruses, protozoa play a significant role in people's lives. Since ancient times, people have used them in the processes of baking, making wine and beer, and in various industries.

Microorganisms assist humans in the production of efficient protein nutrients and biogas. They are used in the application of biotechnical methods of air and wastewater purification, in the use of biological methods for the destruction of agricultural pests, in the production of medicinal preparations, in the destruction of waste materials.

The main purpose of this work is to study the methods and conditions for the cultivation of microorganisms

Familiarize yourself with the areas of application of microorganisms

Study the morphology and physiology of microorganisms

To study the main types and composition of nutrient media

Give the concept and get acquainted with the bioreactor

Disclose the main methods of cultivating microorganisms

Morphology and physiology of microorganisms

Morphology

Classification of microorganisms

bacteria

Bacteria are single-celled prokaryotic microorganisms. Their value is measured in micrometers (µm). There are three main forms: spherical bacteria - cocci, rod-shaped and convoluted.

cocci(Greek kokkos - grain) have a spherical or slightly elongated shape. They differ from each other depending on how they are located after division. Solitarily arranged cocci are micrococci, arranged in pairs are diplococci. Streptococci divide in the same plane and after division do not diverge, forming chains (Greek streptos - chain). Tetracocci form combinations of four cocci as a result of division in two mutually perpendicular planes, sarcins (Latin sarcio - to bind) are formed when dividing in three mutually perpendicular planes and look like clusters of 8-16 cocci. Staphylococci, as a result of random division, form clusters resembling a bunch of grapes (Greek staphyle - bunch of grapes).

rod-shaped bacteria (Greek bacteria - stick) that can form spores are called bacilli if the spore is not wider than the stick itself, and clostridium if the spore diameter exceeds the diameter of the stick. Rod-shaped bacteria, unlike cocci, are diverse in size, shape and arrangement of cells: short (1-5 microns), thick, with rounded ends bacteria of the intestinal group; thin, slightly curved rods of tuberculosis; thin sticks of diphtheria located at an angle; large (3-8 microns) sticks anthrax with "chopped off" ends, forming long chains - streptobacilli.

To tortuous forms of bacteria include vibrios, which have a slightly curved shape in the form of a comma (cholera vibrio) and spirilla, consisting of several curls. The crimped forms also include Campylobacter, which under a microscope look like the wings of a flying gull.

The structure of a bacterial cell.

Structural elements of a bacterial cell can be divided into:

a) permanent structural elements - are present in each type of bacteria, throughout the life of a bacterium; it is a cell wall, cytoplasmic membrane, cytoplasm, nucleoid;

B) non-permanent structural elements that not all types of bacteria are able to form, but those bacteria that form them can lose them and acquire them again, depending on the conditions of existence. This is a capsule, inclusions, drank, spores, flagella.

Rice. 1.1. Structure of a bacterial cell

cell wall covers the entire surface of the cell. In gram-positive bacteria, the cell wall is thicker: up to 90% is a polymeric compound peptidoglycan associated with teichoic acids and a protein layer. In gram-negative bacteria, the cell wall is thinner, but more complex in composition: it consists of a thin layer of peptidoglycan, lipopolysaccharides, proteins; it is covered by an outer membrane.

Functions of the cell wallare that it:

Is an osmotic barrier

Determines the shape of a bacterial cell

Protects the cell from environmental influences

Carries a variety of receptors that promote the attachment of phages, colicins, as well as various chemical compounds,

Nutrients enter the cell through the cell wall and waste products are excreted.

O-antigen is localized in the cell wall and endotoxin (lipid A) of bacteria is associated with it.

cytoplasmic membrane

adjacent to the bacterial cell wall cytoplasmic membrane , whose structure is similar to eukaryotic membranes ( consists of a double layer of lipids, mainly phospholipids with built-in surface and integral proteins). She provides:

Selective permeability and transport of solutes into the cell,

Electron transport and oxidative phosphorylation,

Isolation of hydrolytic exoenzymes, biosynthesis of various polymers.

The cytoplasmic membrane limits bacterial cytoplasm , which represents granular structure. Localized in the cytoplasm ribosomes and bacterial nucleoid, it can also contain inclusions and plasmids(extrachromosomal DNA). In addition to the required structures, bacterial cells may have spores.

Cytoplasm- the internal gel-like contents of a bacterial cell are permeated with membrane structures that create a rigid system. The cytoplasm contains ribosomes (in which protein biosynthesis is carried out), enzymes, amino acids, proteins, ribonucleic acids.

Nucleoid- it is a bacterial chromosome, a double strand of DNA, annularly closed, connected to the mesosome. Unlike the nucleus of eukaryotes, the DNA strand is freely located in the cytoplasm, does not have a nuclear membrane, nucleolus, or histone proteins. The DNA strand is many times longer than the bacterium itself (for example, in E. coli, the length of the chromosome is more than 1 mm).

In addition to the nucleoid, extrachromosomal factors of heredity, called plasmids, can be found in the cytoplasm. These are short, circular strands of DNA attached to mesosomes.

Inclusions are found in the cytoplasm of some bacteria in the form of grains that can be detected by microscopy. For the most part, this is a supply of nutrients.

drinking(lat. pili - hairs) otherwise cilia, fimbriae, fringes, villi - short filamentous processes on the surface of bacteria.

Flagella. Many types of bacteria are able to move due to the presence of flagella. Of the pathogenic bacteria, only among the rods and convoluted forms are there mobile species. Flagella are thin elastic filaments, the length of which in some species is several times the length of the body of the bacterium itself.

The number and arrangement of flagella is a characteristic species feature of bacteria. Bacteria are distinguished: monotrichous - with one flagellum at the end of the body, lophotrichous - with a bundle of flagella at the end, amphitrichous, having flagella at both ends, and peritrichous, in which the flagella are located over the entire surface of the body. Vibrio cholerae belongs to monotrichs, and typhoid salmonella belongs to peritrichs.

Capsule- the outer mucous layer found in many bacteria. In some species, it is so thin that it is found only in an electron microscope - this is a microcapsule. In other types of bacteria, the capsule is well defined and visible in a conventional optical microscope - this is a macrocapsule.

Mycoplasmas

Mycoplasmas are prokaryotes, their size is 125-200 nm. These are the smallest of cellular microbes, their size is close to the resolution limit of an optical microscope. They lack a cell wall. The characteristic features of mycoplasmas are associated with the absence of a cell wall. They do not have a permanent shape, so there are spherical, oval, thread-like shapes.

Rickettsia

Chlamydia

actinomycetes

Actinomycetes are unicellular microorganisms that belong to prokaryotes. Their cells have the same structure as bacteria: a cell wall containing peptidoglycan, a cytoplasmic membrane; nucleoid, ribosomes, mesosomes, intracellular inclusions are located in the cytoplasm. Therefore, pathogenic actinomycetes are sensitive to antibacterial drugs. At the same time, they have a form of branching interlacing filaments similar to fungi, and some actinomycetes belonging to the strenomycete family reproduce by spores. Other families of actinomycetes reproduce by fragmentation, that is, the breakdown of filaments into separate fragments.

Actinomycetes are widely distributed in the environment, especially in the soil, and participate in the cycle of substances in nature. Among actinomycetes there are producers of antibiotics, vitamins, hormones. Most of the antibiotics currently used are produced by actinomycetes. These are streptomycin, tetracycline and others.

Spirochetes.

Spirochetes are prokaryotes. They have features in common with both bacteria and protozoa. These are unicellular microbes, having the form of long thin spirally curved cells, capable of active movement. Under adverse conditions, some of them can turn into a cyst.

Studies in an electron microscope made it possible to establish the structure of spirochete cells. These are cytoplasmic cylinders surrounded by a cytoplasmic membrane and a cell wall containing peptidoglycan. The cytoplasm contains the nucleoid, ribosomes, mesosomes, and inclusions.

Fibrils are located under the cytoplasmic membrane, providing a variety of movement of spirochetes - translational, rotational, flexion.

Pathogenic representatives of spirochetes: Treponema pallidum - causes syphilis, Borrelia recurrentis - relapsing fever, Borrelia burgdorferi - Lyme disease, Leptospira interrogans - leptospirosis.

Mushrooms

Mushrooms (Fungi, Mycetes) - eukaryotes, lower plants, devoid of chlorophyll, and therefore they do not synthesize organic carbon compounds, that is, they are heterotrophs, have a differentiated nucleus, are covered with a shell containing chitin. Unlike bacteria, fungi do not contain peptidoglycan, and therefore are insensitive to penicillins. The cytoplasm of fungi is characterized by the presence of a large number of various inclusions and vacuoles.

Among microscopic fungi (micromycetes) there are unicellular and multicellular microorganisms that differ in morphology and methods of reproduction. Fungi are characterized by a variety of methods of reproduction: division, fragmentation, budding, the formation of spores - asexual and sexual.

In microbiological studies, molds, yeasts and representatives of the combined group of so-called imperfect fungi are most often encountered.

Mold form a typical mycelium, creeping along the nutrient substrate. From the mycelium, aerial branches rise upwards, which end in fruiting bodies. various shapes carrying spores.

Mucor or capitate molds (Mucor) are unicellular fungi with a spherical fruiting body filled with endospores.

Molds of the genus Aspergillus are multicellular fungi with a fruiting body, microscopy resembling the tip of a watering can spraying streams of water; hence the name "leak mold". Some Aspergillus species are used industrially to produce citric acid and other substances. There are species that cause diseases of the skin and lungs in humans - aspergillosis.

Molds of the genus Penicillum, or brushes, are multicellular fungi with a fruiting body in the form of a brush. From some types of green mold, the first antibiotic, penicillin, was obtained. Among penicilli there are species pathogenic for humans that cause penicilliosis.

Various types of mold can cause spoilage of food, medicines, biologicals.

Yeast - yeast fungi (Saccharomycetes, Blastomycetes) have the shape of round or oval cells, many times larger than bacteria. The average size of yeast cells is approximately equal to the diameter of an erythrocyte (7-10 microns).

Viruses

Viruses- (lat. virus poison) - the smallest microorganisms that do not have a cellular structure, a protein-synthesizing system and are capable of reproducing only in the cells of highly organized life forms. They are widely distributed in nature, affecting animals, plants and other microorganisms.

A mature viral particle, known as a virion, consists of a nucleic acid - genetic material (DNA or RNA) that carries information about several types of proteins necessary for the formation of a new virus - covered with a protective protein shell - capsid. The capsid is made up of identical protein subunits called capsomeres. Viruses may also have a lipid envelope over the capsid ( supercapsid) formed from the membrane of the host cell. The capsid is composed of proteins encoded by the viral genome, and its shape underlies the classification of viruses by morphological trait. Intricately organized viruses, in addition, encode special proteins that help in the assembly of the capsid. Complexes of proteins and nucleic acids are known as nucleoproteins, and the complex of proteins of the viral capsid with the viral nucleic acid is called nucleocapsid.

Rice. 1.4. Schematic structure of the virus: 1 - core (single-stranded RNA); 2 - protein shell (Capsid); 3 - additional lipoprotein membrane; 4 - Capsomeres (structural parts of the Capsid).

Physiology of microorganisms

The physiology of microorganisms studies the vital activity of microbial cells, the processes of their nutrition, respiration, growth, reproduction, patterns of interaction with the environment.

Metabolism

Metabolism- a set of biochemical processes aimed at obtaining energy and reproducing cellular material.

Features of metabolism in bacteria:

1) the variety of substrates used;

2) intensity of metabolic processes;

4) the predominance of decay processes over synthesis processes;

5) the presence of exo- and endoenzymes of metabolism.

Metabolism consists of two interrelated processes: catabolism and anabolism.

catabolism(energy metabolism) is the process of splitting large molecules into smaller ones, as a result of which energy is released that accumulates in the form of ATP:

a) breathing

b) fermentation.

Anabolism(constructive metabolism) - provides the synthesis of macromolecules from which the cell is built:

a) anabolism (with energy costs);

b) catabolism (with the release of energy);

In this case, the energy obtained in the process of catabolism is used. The metabolism of bacteria is characterized by a high rate of the process and rapid adaptation to changing environmental conditions.

In the microbial cell, enzymes are biological catalysts. According to the structure, they distinguish:

1) simple enzymes (proteins);

2) complex; consist of protein (active center) and non-protein parts; required for enzyme activation.

According to the place of action, there are:

1) exoenzymes (act outside the cell; take part in the process of disintegration of large molecules that cannot penetrate inside the bacterial cell; characteristic of gram-positive bacteria);

2) endoenzymes (act in the cell itself, provide the synthesis and breakdown of various substances).

Depending on the chemical reactions catalyzed, all enzymes are divided into six classes:

1) oxidoreductases (catalyze redox reactions between two substrates);

2) transferases (carry out intermolecular transfer of chemical groups);

3) hydrolases (perform hydrolytic cleavage of intramolecular bonds);

4) lyases (attach chemical groups two bonds, and also carry out reverse reactions);

5) isomerases (carry out isomerization processes, provide internal conversion with the formation of various isomers);

6) ligases, or synthetases (connect two molecules, resulting in the splitting of pyrophosphate bonds in the ATP molecule).

Food

Nutrition is understood as the processes of entry and removal of nutrients into and out of the cell. Nutrition primarily ensures the reproduction and metabolism of the cell.

Various organic and inorganic substances enter the bacterial cell in the process of nutrition. Bacteria have no special food organs. Substances penetrate the entire surface of the cell in the form of small molecules. This way of eating is called holophytic. A necessary condition for the passage of nutrients into the cell is their solubility in water and a small value (i.e., proteins must be hydrolyzed to amino acids, carbohydrates to di- or monosaccharides, etc.).

The main regulator of the entry of substances into the bacterial cell is the cytoplasmic membrane. There are four main mechanisms for the intake of substances:

-passive diffusion- along the concentration gradient, energy-intensive, without substrate specificity;

- facilitated diffusion- along the concentration gradient, substrate-specific, energy-intensive, carried out with the participation of specialized proteins permease;

- active transport- against the concentration gradient, substrate-specific (special binding proteins in combination with permeases), energy-consuming (due to ATP), substances enter the cell in a chemically unchanged form;

- translocation (transfer of groups) - against the concentration gradient, with the help of the phosphotransferase system, energy-consuming, substances (mainly sugars) enter the cell in a phorforylated form.

The main chemical elements are organogens necessary for the synthesis of organic compounds - carbon, nitrogen, hydrogen, oxygen.

Food types. The wide distribution of bacteria is facilitated by a variety of types of nutrition. Microbes need carbon, oxygen, nitrogen, hydrogen, sulfur, phosphorus and other elements (organogens).

Depending on the source of carbon production, bacteria are divided into:

1) autotrophs (use inorganic substances - CO2);

2) heterotrophs;

3) metatrophs (use organic matter of inanimate nature);

4) paratrophs (use organic substances of wildlife).

Nutritional processes must provide the energy needs of the bacterial cell.

According to energy sources, microorganisms are divided into:

1) phototrophs (able to use solar energy);

2) chemotrophs (receive energy through redox reactions);

3) chemolithotrophs (use inorganic compounds);

4) chemoorganotrophs (use organic matter).

Bacteria include:

1) prototrophs (they are able to synthesize the necessary substances from low-organized ones themselves);

2) auxotrophs (they are mutants of prototrophs that have lost genes; they are responsible for the synthesis of certain substances - vitamins, amino acids, therefore they need these substances in finished form).

Microorganisms assimilate nutrients in the form of small molecules; therefore, proteins, polysaccharides, and other biopolymers can serve as food sources only after they have been broken down by exoenzymes into simpler compounds.

respiration of microorganisms.

Microorganisms obtain energy through respiration. Respiration is the biological process of electron transfer through the respiratory chain from donors to acceptors to form ATP. Depending on what is the final electron acceptor, emit aerobic and anaerobic respiration. In aerobic respiration, the final electron acceptor is molecular oxygen (O 2), in anaerobic respiration, bound oxygen (-NO 3, \u003d SO 4, \u003d SO 3).

Aerobic respiration hydrogen donor H 2 O

Anaerobic respiration

Nitrate oxidation of NO 3

(facultative anaerobes) hydrogen donor N 2

Sulphate oxidation of SO 4

(obligate anaerobes) hydrogen donor H 2 S

According to the type of respiration, four groups of microorganisms are distinguished.

1.obligate(strict) aerobes. They need molecular (atmospheric) oxygen to breathe.

2.microaerophiles need a reduced concentration (low partial pressure) of free oxygen. To create these conditions, CO 2 is typically added to the culture gas mixture, for example up to 10 percent concentration.

3.Facultative anaerobes can consume glucose and reproduce under aerobic and anaerobic conditions. Among them, there are microorganisms that are tolerant to relatively high (close to atmospheric) concentrations of molecular oxygen - i.e. aerotolerant,

as well as microorganisms that are able, under certain conditions, to switch from anaerobic to aerobic respiration.

4.Strict anaerobes reproduce only under anaerobic conditions, i.e. at very low concentrations of molecular oxygen, which is harmful to them in high concentrations. Biochemically, anaerobic respiration proceeds according to the type of fermentation processes, while molecular oxygen is not used.

Aerobic respiration is energetically more efficient (more ATP is synthesized).

In the process of aerobic respiration, toxic oxidation products are formed (H 2 O 2 - hydrogen peroxide, -O 2 - free oxygen radicals), which are protected by specific enzymes, primarily catalase, peroxidase, peroxide dismutase. Anaerobes lack these enzymes, as well as regulation system redox potential (rH 2).

Growth and reproduction of bacteria

Bacterial growth is an increase in the size of a bacterial cell without increasing the number of individuals in the population.

Reproduction of bacteria is a process that ensures an increase in the number of individuals in a population. Bacteria are characterized by a high rate of reproduction.

Growth always precedes reproduction. Bacteria reproduce by transverse binary fission, in which two identical daughter cells are formed from one mother cell.

The process of bacterial cell division begins with the replication of chromosomal DNA. At the point of attachment of the chromosome to the cytoplasmic membrane (the replicator point), an initiator protein acts, which causes the chromosome ring to break, and then its threads are despiralized. The filaments unwind and the second filament attaches to the cytoplasmic membrane at the proreplicator point, which is diametrically opposed to the replicator point. Due to DNA polymerases, an exact copy of it is completed in the matrix of each strand. The doubling of genetic material is the signal for doubling the number of organelles. In septal mesosomes, a septum is being built, dividing the cell in half. Double-stranded DNA spiralizes, twists into a ring at the point of attachment to the cytoplasmic membrane. This is a signal for the divergence of cells along the septum. Two daughter individuals are formed.

Reproduction of bacteria is determined by the time of generation. This is the period during which cell division takes place. The duration of generation depends on the type of bacteria, age, composition of the nutrient medium, temperature, etc.

Nutrient media

For the cultivation of bacteria, nutrient media are used, to which a number of requirements are imposed.

1. Nutrition. The bacteria must contain all the necessary nutrients.

2. Isotonic. Bacteria must contain a set of salts to maintain osmotic pressure, a certain concentration of sodium chloride.

3. Optimal pH (acidity) of the medium. The acidity of the environment ensures the functioning of bacterial enzymes; for most bacteria is 7.2–7.6.

4. Optimum electronic potential, indicating the content of dissolved oxygen in the medium. It should be high for aerobes and low for anaerobes.

5. Transparency (growth of bacteria was observed, especially for liquid media).

6. Sterility (absence of other bacteria).

Classification of culture media

1. By origin:

1) natural (milk, gelatin, potatoes, etc.);

2) artificial - environments prepared from specially prepared natural ingredients(peptone, aminopeptide, yeast extract, etc.);

3) synthetic - media of known composition, prepared from chemically pure inorganic and organic compounds (salts, amino acids, carbohydrates, etc.).

2. By composition:

1) simple - meat-peptone agar, meat-peptone broth, Hottinger agar, etc.;

2) complex - these are simple with the addition of an additional nutrient component (blood, chocolate agar): sugar broth,

bile broth, serum agar, yolk-salt agar, Kitt-Tarozzi medium, Wilson-Blair medium, etc.

3. By consistency:

1) solid (contain 3-5% agar-agar);

2) semi-liquid (0.15-0.7% agar-agar);

3) liquid (do not contain agar-agar).

agar- complex polysaccharide from seaweed, the main hardener for dense (solid) media.

4. Depending on the purpose of the PS, there are:

Differential diagnostic

elective

selective

inhibitory

Culture media

Cumulative (saturation, enrichment)

Preservative

Control.

Differential diagnostic - these are complex environments on which microorganisms of different species grow in different ways, depending on the biochemical properties of the culture. They are designed to identify species affiliation microorganisms are widely used in clinical bacteriology and genetic research.

Selective, inhibitory and elective PSs are designed for growing a strictly defined type of microorganism. These media serve to isolate bacteria from mixed populations and differentiate them from similar species. Various substances are added to their composition that inhibit the growth of some species and do not affect the growth of others.

The medium can be made selective due to the pH value. Recently, antimicrobial agents such as antibiotics and other chemotherapeutic agents have been used as media selective agents.

Elective PS found wide application in the isolation of causative agents of intestinal infections. With the addition of malachite or brilliant green, bile salts (in particular sodium taurocholic acid), a significant amount of sodium chloride or citrate salts, the growth of Escherichia coli is inhibited, but the growth of pathogenic bacteria of the intestinal group does not worsen. Some elective media are prepared with the addition of antibiotics.

Culture maintenance media are formulated to be free from selective substances capable of causing culture variability.

Cumulative PS (enrichment, saturation) are media on which certain types crops or groups of crops grow faster and more intensively than accompanying crops. When cultivating on these media, inhibitory substances are usually not used, but, on the contrary, favorable conditions are created for a particular species present in the mixture. The basis of accumulation media are bile and its salts, sodium tetrathionate, various dyes, selenite salts, antibiotics, etc.

Preservative media are used for primary inoculation and transportation of the test material.

There are also control PS, which are used to control the sterility and total bacterial contamination of antibiotics.

5. According to the set of nutrients, they distinguish:

Minimal media that contain only food sources sufficient for growth;

Rich environments, which include many additional substances.

6. According to the scale of use, PS are divided into:

> production (technological);

> environments for scientific research with a limited scope of application.

Production PS should be available, economical, easy to prepare and use for large-scale cultivation. Research media are usually synthetic and rich in nutrients.

Selection of raw materials for the construction of culture media

The quality of PS is largely determined by the usefulness of the composition of nutrient substrates and raw materials used for their preparation. Big variety types of raw materials poses a difficult task of choosing the most promising, suitable for designing PS of the required quality. The decisive role in this matter is played, first of all, by the biochemical indicators of the composition of raw materials, which determine the choice of the method and modes of its processing in order to achieve the most complete and effective use the nutrients it contains.

To obtain PS with especially valuable properties, traditional animal protein sources are primarily used, namely meat cattle (cattle), casein, fish and products of its processing. The most fully developed and widely used PS based on cattle meat.

Given the shortage of Caspian sprat, which was widely used in the recent past, cheaper and more accessible non-food products of the fishing industry began to be used to obtain fish nutritional bases - dry krill, krill meat processing waste, filleted walleye pollock and its overripe caviar. The most widely used fish feed meal (RCM), which meets the requirements biological value, accessibility and relative standard.

Fairly widespread PS based on casein, which contains all the components found in milk: fat, lactose, vitamins, enzymes and salts. However, it should be noted that due to the increase in the cost of milk processing products, as well as the increase in demand for casein in the world market, its use is somewhat limited.

From non-food sources of protein of animal origin, as a raw material for constructing full-fledged PS, it is necessary to isolate the blood of slaughter animals, which is rich in biologically active substances and microelements and contains products of cellular and tissue metabolism.

Blood hydrolysates of farm animals are used as substitutes for peptone in differential diagnostic nutrient media.

Other types of protein-containing raw materials of animal origin that can be used for the construction of PS include: the placenta and spleen of cattle, dry protein concentrate - a product of meat waste processing, split trim obtained during skin processing, poultry embryos - a waste of vaccine production, blood substitutes with expired, curd whey, soft tissues of mollusks and pinnipeds.

It is promising to use carcasses of fur-bearing animals from fur farms, cattle blood obtained at a meat processing plant, skimmed milk and whey (waste from butter factories).

In general, PS prepared from raw materials of animal origin have a high content of main nutritional components, are complete and balanced in terms of amino acid composition, and are quite well studied.

From plant products, corn, soybeans, peas, potatoes, lupine, etc. can be used as a protein substrate for PS. However, vegetable agricultural raw materials contain protein, the unbalanced composition of which depends on crop growing conditions, as well as lipids in larger quantities than products animal origin.

An extensive group consists of PS made from protein raw materials of microbial origin (yeast, bacteria, etc.). The amino acid composition of microorganisms that serve as a substrate for the preparation of PS is well studied, and the biomass of the microorganisms used is complete in terms of nutrient composition and is characterized by an increased content of lysine and threonine.

A number of PSs of combined composition from protein substrates of various origins have been developed. These include yeast casein broth, yeast meat, etc. Most of the known PS are based on hydrolysates of casein, cattle meat and fish (up to 80%).

The specific weight of non-food raw materials in the PS design technology is only 15% and needs to be increased in the future.

Non-food raw materials used to obtain a nutritional base (PS) must meet certain requirements, namely:

^ complete (quantitative and qualitative composition of raw materials should mainly meet the nutritional needs of microorganisms and cells for which PS are being developed);

^ affordable (to have a fairly extensive raw material base);

^ technological (the cost of introducing into production should be carried out using existing equipment or existing technology);

^ economical (the cost of introducing technology when switching to new raw materials and its processing should not exceed the cost norms for obtaining the target product);

^ standard (have a long shelf life without changing the physico-chemical properties and nutritional value)

Periodic system

A periodic culture system is a system in which, after the introduction of bacteria (inoculation) into the nutrient medium, neither the addition nor the removal of any components other than the gas phase is performed. It follows that the periodic system can support cell reproduction for a limited time, during which the composition of the nutrient medium changes from favorable (optimal) for their growth to unfavorable, up to the complete cessation of cell growth.

Bacteria have been living on planet Earth for more than 3.5 billion years. During this time they have learned a lot and adapted to a lot. Now they are helping people. Bacteria and man became inseparable. The total mass of bacteria is enormous. It is about 500 billion tons.

Beneficial bacteria perform two of the most important ecological functions - they fix nitrogen and participate in the mineralization of organic residues. The role of bacteria in nature is global. They are involved in the movement, concentration and dispersion of chemical elements in the earth's biosphere.

The importance of bacteria beneficial to humans is great. They make up 99% of the entire population that inhabit his body. Thanks to them, a person lives, breathes and eats.

Important. They provide complete life support.

Bacteria are pretty simple. Scientists suggest that they first appeared on planet Earth.

Beneficial bacteria in the human body

The human body is inhabited by both useful and. The existing balance between the human body and bacteria has been polished for centuries.

As scientists have calculated, the human body contains from 500 to 1000 different types of bacteria or trillions of these amazing tenants, which is up to 4 kg of total weight. Up to 3 kilograms of microbial bodies is found only in the intestines. The rest of them are in the urogenital tract, on the skin and other cavities of the human body. Microbes fill the body of a newborn from the first minutes of his life and finally form the composition of the intestinal microflora by 10-13 years.

Streptococci, lactobacilli, bifidobacteria, enterobacteria, fungi, intestinal viruses, non-pathogenic protozoa live in the intestine. Lactobacilli and bifidobacteria make up 60% of the intestinal flora. The composition of this group is always constant, they are the most numerous and perform the main functions.

bifidobacteria

The importance of this type of bacteria is enormous.

• Thanks to them, acetate and lactic acid are produced. By acidifying their habitat, they inhibit the growth that causes decay and fermentation.
• Thanks to bifidobacteria, the risk of developing food allergies in babies is reduced.
• They provide antioxidant and antitumor effects.
• Bifidobacteria are involved in the synthesis of vitamin C.
• Bifido- and lactobacilli are involved in the absorption of vitamin D, calcium and iron.

Rice. 1. The photo shows bifidobacteria. Computer visualization.

coli

The importance of this type of bacteria for humans is great.

• Special attention is paid to the representative of this genus Escherichia coli M17. It is able to produce the substance cocilin, which inhibits the growth of a number of pathogenic microbes.
• With the participation, vitamins K, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.

Rice. 2. The photo shows E. coli (3D computer image).

The positive role of bacteria in human life

• With the participation of bifido-, lacto-, and enterobacteria, vitamins K, C, group B (B1, B2, B5, B6, B7, B9 and B12), folic and nicotinic acids are synthesized.
• Due to the breakdown of undigested food components from the upper intestines - starch, cellulose, protein and fat fractions.
• The intestinal microflora maintains water-salt metabolism and ionic homeostasis.
• Due to the secretion of special substances, the intestinal microflora inhibits the growth of pathogenic bacteria that cause putrefaction and fermentation.
• Bifido-, lacto-, and enterobacteria take part in the detoxification of substances that enter from the outside and are formed inside the body itself.
• The intestinal microflora plays an important role in restoring local immunity. Thanks to it, the number of lymphocytes, the activity of phagocytes and the production of immunoglobulin A increase.
• Thanks to the intestinal microflora, the development of the lymphoid apparatus is stimulated.
• The resistance of the intestinal epithelium to carcinogens increases.
• Microflora protect the intestinal mucosa and provide energy to the intestinal epithelium.
• They regulate intestinal motility.
• The intestinal flora acquires the skills to capture and remove viruses from the host organism, with which it has been in symbiosis for many years.
• The importance of bacteria in maintaining the body's thermal balance is great. The intestinal microflora feeds on substances that are not digested by the enzymatic system, which come from the upper sections. gastrointestinal tract. As a result of complex biochemical reactions, a huge amount of thermal energy is produced. Heat is carried throughout the body with blood flow and enters all internal organs. That is why a person always freezes when starving.
• The intestinal microflora regulates the reabsorption of bile acid components (cholesterol), hormones, etc.

Rice. 3. In the photo, beneficial bacteria are lactobacilli (3D computer image).

The role of bacteria in nitrogen production

ammonifying microbes(causing decay), with the help of a number of enzymes they have, they are able to decompose the remains of dead animals and plants. When proteins decompose, nitrogen and ammonia are released.

Urobacteria decompose urea, which man and all animals of the planet secrete daily. Its quantity is huge and reaches 50 million tons per year.

A certain type of bacteria is involved in the oxidation of ammonia. This process is called nitrofication.

Denitrifying microbes return molecular oxygen from the soil to the atmosphere.

Rice. 4. In the photo, beneficial bacteria are ammonifying microbes. They expose the remains of dead animals and plants to decomposition.

The role of bacteria in nature: nitrogen fixation

The importance of bacteria in the life of humans, animals, plants, fungi and bacteria is enormous. As you know, nitrogen is necessary for their normal existence. But bacteria cannot absorb nitrogen in the gaseous state. It turns out that blue-green algae can bind nitrogen and form ammonia ( cyanobacteria), free-living nitrogen fixers and special . All these useful bacteria produce up to 90% of the bound nitrogen and involve up to 180 million tons of nitrogen in the nitrogen fund of the soil.

Nodule bacteria coexist well with leguminous plants and sea buckthorn.

Plants such as alfalfa, peas, lupins and other legumes have so-called "apartments" for nodule bacteria on their roots. These plants are planted on depleted soils to enrich them with nitrogen.

Rice. 5. In the photo nodule bacteria on the surface of the root hair of a leguminous plant.

Rice. 6. Photo of the root of a leguminous plant.

Rice. 7. In the photo, beneficial bacteria are cyanobacteria.

The role of bacteria in nature: the carbon cycle

Carbon is the most important cellular substance of the animal and plant world, as well as the plant world. It makes up 50% of the dry matter of the cell.

A lot of carbon is found in the fiber that animals eat. In their stomach, fiber decomposes under the action of microbes and then, in the form of manure, gets outside.

Decompose fiber cellulose bacteria. As a result of their work, the soil is enriched with humus, which significantly increases its fertility, and carbon dioxide is returned to the atmosphere.

Rice. 8. Intracellular symbionts are colored green, the mass of processed wood is colored yellow.

The role of bacteria in the conversion of phosphorus, iron and sulfur

Proteins and lipids contain a large amount of phosphorus, the mineralization of which is carried out You. megatherium(from the genus of putrefactive bacteria).

iron bacteria participate in the processes of mineralization of organic compounds containing iron. As a result of their activities, a large amount of iron ore and ferromanganese deposits are formed in swamps and lakes.

Sulfur bacteria live in water and soil. There are many of them in manure. They participate in the process of mineralization of sulfur-containing substances of organic origin. In the process of decomposition of organic sulfur-containing substances, hydrogen sulfide gas is released, which is extremely toxic to the environment, including to all living things. Sulfur bacteria, as a result of their vital activity, turn this gas into an inactive, harmless compound.

Rice. 9. Despite the apparent lifelessness, there is still life in the Rio Tinto River. These are various iron-oxidizing bacteria and many other species that can only be found in this place.

Rice. 10. Green sulfur bacteria in the Winogradsky column.

The role of bacteria in nature: mineralization of organic residues

Bacteria that take an active part in the mineralization of organic compounds are considered cleaners (orderlies) of the planet Earth. With their help, the organic matter of dead plants and animals turns into humus, which soil microorganisms turn into mineral salts, which are so necessary for building the root, stem and leaf systems of plants.

Rice. 11. Mineralization of organic substances entering the reservoir occurs as a result of biochemical oxidation.

The role of bacteria in nature: fermentation of pectins

The cells of plant organisms bind to each other (cement) with a special substance called pectin. Some types of butyric acid bacteria have the ability to ferment this substance, which, when heated, turns into a gelatinous mass (pectis). This feature is used when soaking plants containing a lot of fibers (flax, hemp).

Rice. 12. There are several ways to obtain trusts. The most common is the biological method, in which the connection of the fibrous part with the surrounding tissues is destroyed under the influence of microorganisms. The process of fermentation of pectin substances of bast plants is called lobe, and soaked straw is called trust.

The role of bacteria in water purification

water purifying bacteria, stabilize the level of its acidity. With their help, bottom sediments are reduced, the health of fish and plants living in the water improves.

Recently, a group of scientists from different countries bacteria have been found that break down detergents found in synthetic detergents and some drugs.

Rice. 13. The activity of xenobacteria is widely used to clean up soils and water bodies contaminated with oil products.

Rice. 14. Plastic domes that purify water. They contain heterotrophic bacteria that feed on carbon-containing materials and autotrophic bacteria that feed on ammonia and nitrogen-containing materials. The tube system keeps them alive.

The use of bacteria in the enrichment of ores

Ability thionic sulfur-oxidizing bacteria used to enrich copper and uranium ores.

Rice. 15. In the photo, beneficial bacteria are Thiobacilli and Acidithiobacillus ferrooxidans (electron micrograph). They are able to extract copper ions for leaching of wastes that are formed during the flotation enrichment of sulfide ores.

The role of bacteria in butyric fermentation

Butyric microbes are everywhere. There are more than 25 types of these microbes. They take part in the process of decomposition of proteins, fats and carbohydrates.

Butyric fermentation is caused by anaerobic spore-forming bacteria belonging to the genus Clostridium. They are able to ferment various sugars, alcohols, organic acids, starch, fiber.

Rice. 16. In the photo, butyric microorganisms (computer visualization).

The role of bacteria in animal life

Many species of the animal world feed on plants, which are based on fiber. To digest fiber (cellulose) animals are helped by special microbes, the residence of which is certain sections of the gastrointestinal tract.

Importance of bacteria in animal husbandry

The vital activity of animals is accompanied by the release of a huge amount of manure. From it, some microorganisms can produce methane ("marsh gas"), which is used as a fuel and raw material in organic synthesis.

Rice. 17. Methane gas as a fuel for cars.

The use of bacteria in the food industry

The role of bacteria in human life is enormous. Widely used in Food Industry lactic acid bacteria:

• in the production of curdled milk, cheeses, sour cream and kefir;
• when fermenting cabbage and pickling cucumbers, they take part in urinating apples and pickling vegetables;
• they give a special flavor to wines;
• produce lactic acid, which ferments milk. This property is used for the production of curdled milk and sour cream;
• in the preparation of cheeses and yogurts on an industrial scale;
• lactic acid serves as a preservative during the brining process.

Lactic acid bacteria are milk streptococci, creamy streptococci, bulgarian, acidophilic, grain thermophilic and cucumber sticks. Bacteria of the genus Streptococcus and Lactobacillus give the products a thicker consistency. As a result of their vital activity, the quality of cheeses improves. They give the cheese a certain cheese flavor.

Rice. 18. In the photo, beneficial bacteria are lactobacilli (pink), Bulgarian stick and thermophilic streptococcus.

Rice. 19. In the photo, beneficial bacteria are kefir (Tibetan or milk) mushroom and lactic acid sticks before being directly introduced into milk.

Rice. 20. Dairy products.

Rice. 21. Thermophilic streptococci (Streptococcus thermophilus) are used in the preparation of mozzarella cheese.

Rice. 22. There are many options for mold penicillin. Velvety crust, greenish veins, unique taste and medicinal ammonia aroma of cheeses are unique. The mushroom taste of cheeses depends on the place and duration of ripening.

Rice. 23. Bifiliz - a biological preparation for oral administration, containing a mass of live bifidobacteria and lysozyme.

The use of yeast and fungi in the food industry

The food industry mainly uses the yeast species Saccharomyces cerevisiae. They carry out alcoholic fermentation, which is why they are widely used in the baking business. The alcohol evaporates during baking, and carbon dioxide bubbles form the bread crumb.

Since 1910, yeast has been added to sausages. Yeast of the species Saccharomyces cerevisiae is used for the production of wines, beer and kvass.

Rice. 24. Kombucha is a friendly symbiosis of vinegar sticks and yeast. It appeared in our area in the last century.

Rice. 25. Dry and wet yeast are widely used in the baking industry.

Rice. 26. Microscopic view of Saccharomyces cerevisiae yeast cells and Saccharomyces cerevisiae - "real" wine yeast.

The role of bacteria in human life: acetic acid oxidation

Pasteur also proved that special microorganisms take part in acetic acid oxidation - vinegar sticks which are widely found in nature. They settle on plants, penetrate into ripened vegetables and fruits. There are many of them in pickled vegetables and fruits, wine, beer and kvass.

The ability of vinegar sticks to oxidize ethyl alcohol to acetic acid is used today to produce vinegar used for food purposes and in the preparation of animal feed - ensiling (canning).

Rice. 27. The process of ensiling fodder. Silage is a succulent feed with a high nutritional value.

The role of bacteria in human life: the production of drugs

The study of the vital activity of microbes has allowed scientists to use some bacteria for the synthesis of antibacterial drugs, vitamins, hormones and enzymes.

They help fight many infectious and viral diseases. Most antibiotics are produced actinomycetes, less often non-micellar bacteria. Penicillin, derived from fungi, destroys the cell wall of bacteria. Streptomycetes produce streptomycin, which inactivates the ribosomes of microbial cells. hay sticks or Bacillus subtilis acidify the environment. They inhibit the growth of putrefactive and conditionally pathogenic microorganisms due to the formation of a number of antimicrobial substances. Hay stick produces enzymes that destroy substances that are formed as a result of the putrefactive decay of tissues. They are involved in the synthesis of amino acids, vitamins and immunoactive compounds.

Using the technology of genetic engineering, today scientists have learned to use for the production of insulin and interferon.

A number of bacteria are supposed to be used to produce a special protein that can be added to livestock feed and human food.

Rice. 28. In the photo, spores of hay bacillus or Bacillus subtilis (painted blue).

Rice. 29. Biosporin-Biopharma is a domestic drug containing apathogenic bacteria of the genus Bacillus.

Using bacteria to produce safe herbicides

Today, the technique is widely used phytobacteria for the production of safe herbicides. toxins Bacillus thuringiensis emit Cry-toxins dangerous for insects, which makes it possible to use this feature of microorganisms in the fight against plant pests.

The use of bacteria in the production of detergents

Proteases or cleave peptide bonds between the amino acids that make up proteins. Amylase breaks down starch. hay stick (B. subtilis) produces proteases and amylases. Bacterial amylases are used in the manufacture of laundry detergent.

Rice. 30. The study of the vital activity of microbes allows scientists to apply some of their properties for the benefit of man.

The importance of bacteria in human life is enormous. Beneficial bacteria have been constant companions of man for many millennia. The task of mankind is not to disturb this delicate balance that has developed between the microorganisms living inside us and in the environment. The role of bacteria in human life is enormous. Scientists are constantly discovering beneficial features microorganisms, the use of which Everyday life and in production is limited only by their properties.

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