The world around us amazes with the variety of species of its inhabitants. According to the latest census of this “population” of the Earth, 6.6 million species live on land and another 2.2 million roam the ocean depths. Each species is a link in a single chain of the biosystem of our planet. Of these, the smallest living organisms are bacteria. What has humanity managed to learn about these tiny creatures?

What are bacteria and where do they live?

Bacteria - This single-celled organisms microscopic sizes, one of the types of microbes.

Their prevalence on Earth is truly amazing. They live in the ice of the Arctic and on the ocean floor, in outer space, in hot springs - geysers and in the saltiest bodies of water.

The total weight of these “charming little ones” that have occupied the human body reaches 2 kg! This is despite the fact that their sizes rarely exceed 0.5 microns. A huge number of bacteria inhabit the body of animals, performing various functions there.

A living thing and the bacteria in its body influence each other's health and well-being. When a species of animal becomes extinct, its unique bacteria also die.

Looking at them appearance, one can only marvel at the ingenuity of nature. These “charms” can have rod-shaped, spherical, spiral and other shapes. At the same time most of them are colorless, only rare species are colored green and purple look. Moreover, over billions of years they change only internally, but their appearance remains unchanged.

Discoverer of bacteria

The first explorer of the microworld was a Dutch naturalist Anthony Van Leeuwenhoek. His name became famous thanks to the activity to which he devoted all his free time. He was passionate about manufacturing and achieved amazing success in this business. It is to him that the honor of inventing the first microscope belongs. In essence, it was a tiny lens with a diameter of a pea, giving a magnification of 200-300 times. It could only be used by pressing it to the eye.

In 1683, he discovered and later described “live animals” seen through a lens in a drop of rainwater. Over the next 50 years, he studied various microorganisms, describing more than 200 of their species. He sent his observations to England, where gray-haired scientists in powdered wigs just shook their heads, amazed at the discoveries of this unknown self-taught man. It was thanks to Leeuwenhoek’s talent and perseverance that a new science was born - microbiology.

General information about bacteria

Over the past centuries, microbiologists have learned a great deal about the world of these tiny creatures. It turned out that exactly Our planet owes the birth of multicellular life forms to bacteria. They play a major role in maintaining the circulation of substances on Earth. Generations of people replace each other, plants die, household waste and outdated shells of various creatures accumulate - all this is utilized and, with the help of bacteria, decomposes in the process of decay. And the resulting chemical compounds return to environment.

How do humanity and the world of bacteria coexist? Let’s make a reservation that there are “good and bad” bacteria. "Bad" bacteria are to blame for the spread huge amount diseases ranging from plague and cholera to common whooping cough and dysentery. They enter our body through airborne droplets, along with food, water and through the skin. These insidious companions can live in various organs, and while our immunity copes with them, they do not manifest themselves in any way. The speed of their reproduction is amazing. Every 20 minutes their number doubles. This means that one single pathogenic microbe generates a multi-million army in 12 hours the same bacteria that attack the body.

There is another danger posed by bacteria. They cause poisoning people consuming spoiled foods - canned food, sausages, etc.

Defeat in a victorious war

A great breakthrough in the fight against pathogenic bacteria was discovery of penicillin in 1928- the world's first antibiotic. This class of substances is capable of inhibiting the growth and reproduction of bacteria. The early successes of antibiotics were enormous. It was possible to cure diseases that were previously fatal. However, bacteria discovered incredible adaptability and the ability to change in such a way that existing antibiotics were helpless in the fight against even the simplest infections. This the ability of bacteria to mutate has become a real threat to human health and led to the emergence of incurable infections (caused by superbugs).

Bacteria as allies and friends of humanity

Now let's talk about “good” bacteria. The evolution of animals and bacteria occurred in parallel. The structure and functions of living organisms gradually became more complex. Bacteria weren’t dozing either. Animals, including humans, become their home. They settle in the mouth, on the skin, in the stomach and other organs.

Most of them are extremely useful because helps digest food, participates in the synthesis of certain vitamins and even protects us from their pathogenic counterparts. Poor nutrition, stress and indiscriminate use of antibiotics can cause microflora disturbances, which necessarily affects a person’s well-being.

Interestingly, bacteria They are sensitive to people's taste preferences.

In Americans who traditionally consume high-calorie foods (fast foods, hamburgers), bacteria are able to digest foods high in fat. And some Japanese have intestinal bacteria adapted to digest algae.

The role of bacteria in human economic activity

The use of bacteria began even before humanity knew of their existence. Since ancient times, people have made wine, fermented vegetables, knew recipes for making kefir, curdled milk and kumiss, and produced cottage cheese and cheeses.

Much later, it was found that tiny helpers of nature - bacteria - are involved in all these processes.

As knowledge about them deepened, their application expanded. They were “trained” to fight plant pests and enrich the soil with nitrogen, ensile green fodder and purify wastewater, in which they literally devour various organic residues.

Instead of an epilogue

So, humans and microorganisms are interconnected parts of a single natural ecosystem. Between them, along with competition in the struggle for living space, there is mutually beneficial cooperation (symbiosis).

To defend ourselves as a species, we must protect our bodies from the invasion of pathogenic bacteria, and also be extremely careful about the use of antibiotics.

At the same time, microbiologists are working to expand the scope of application of bacteria. An example is a project to create light-sensitive bacteria and use them to produce biological cellulose. When exposed to light, production begins, and when it is turned off, production stops.

The organizers of the project are confident that organs created from this natural biological material will not experience rejection in the body. The proposed technique opens up amazing opportunities for the world to create medical implants.

If this message was useful to you, I would be glad to see you

Methods for determining the total biochemical activity of soil microflora

Characteristics of microbial cellular organization

The role of microorganisms in nature and agriculture

The wide distribution of microorganisms indicates their enormous role in nature. With their participation, various organic substances decompose in soils and water bodies, they determine the circulation of substances and energy in nature; Soil fertility, the formation of coal, oil, and many other minerals depend on their activities. Microorganisms participate in the weathering of rocks and other natural processes.

Many microorganisms are used in industrial and agricultural production. Thus, baking, production of fermented milk products, winemaking, 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 and livestock production is especially important. The enrichment of the soil with nitrogen, the control of crop pests with the help of microbial preparations depend on them, proper preparation and storage of feed, creation of feed protein, antibiotics and substances of microbial origin for animal feeding.

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

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

Recent scientific data have 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 sectors 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 has been discovered: vitamins, amino acids, plant growth stimulants - growth substances, etc. Ways have been found to use the protein of microorganisms to feed farm animals. Microbial preparations have been isolated that enhance the supply of nitrogen from the air to the soil.

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

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

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

Depending on the form in which microorganisms receive carbon from the environment, they are divided into two groups: autotrophic (“feeding themselves”), using carbon dioxide as the sole 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 oxidized substrate, called the 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 through 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 nutrition.

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

In phototrophy, the energy source is sunlight. Photolithoautotrophy is a type of nutrition characteristic of microorganisms that use light energy to synthesize cell substances from C0 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 (order Cyanobacteria1es), like green plants, reduce CO2 to organic matter photochemically using hydrogen from 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 CO2 into organic matter, bacteria of this group use hydrogen, which is part of H25. In this case, sulfur granules accumulate in the cytoplasm, which is then oxidized to sulfuric acid:

С0 2 + 2Н 2 S light-› (СH 2 O) + Н 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, and, in small amounts, bacteriochlorophyll, as well as various carotenoids. Like purple sulfur bacteria, they are strict anaerobes and are capable of oxidizing hydrogen sulfide, sulfides and sulfites during 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. This group includes purple non-sulfur bacteria.

Purple nonsulfur bacteria (family Rhjdospirillaceae) contain bacteriochlorophylls a and b, as well as various carotenoids. They are not capable of oxidizing hydrogen sulfide (H 2 S), accumulating sulfur and releasing 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°, S03 2 -, S 2 03 2- , CO, etc. The oxidation process itself is called chemosynthesis. The carbon for the construction of all components of chemolithoautotroph 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 nitrites), sulfur bacteria (oxidize hydrogen sulfide, elemental sulfur and some simple inorganic sulfur compounds), bacteria that oxidize hydrogen to water, iron bacteria capable of oxidizing divalent iron 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

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

2FeC0 3 + 1/2 0 2 + ZN 2 0 - 2Fe (OH) 3 + 2C0 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, many are aerobic and anaerobic species that live in soils and other substrates.

Bacteria are the most ancient organism on earth, and also the simplest in their structure. It consists of just one cell, which can only be seen and studied under a microscope. A characteristic feature bacteria is the absence of a nucleus, which is why bacteria are classified as prokaryotes.

Some species form small groups of cells; such clusters may be surrounded by a capsule (case). The size, shape and color of the bacterium are highly dependent on the environment.

Bacteria are distinguished by shape into: rod-shaped (bacillus), spherical (cocci) and convoluted (spirilla). There are also modified ones - cubic, C-shaped, star-shaped. Their sizes range from 1 to 10 microns. Certain types of bacteria can actively move using flagella. The latter sometimes exceed the size of the bacterium itself by two times.

Types of forms of bacteria

To move, bacteria use flagella, the number of which varies—one, a pair, or a bundle of flagella. The location of the flagella can also be different - on one side of the cell, on the sides, or evenly distributed throughout the entire plane. Also, one of the methods of movement is considered to be gliding thanks to the mucus with which the prokaryote is covered. Most have vacuoles inside the cytoplasm. Adjusting the gas capacity of the vacuoles helps them move up or down in the liquid, as well as move through the air channels of the soil.

Scientists have discovered more than 10 thousand varieties of bacteria, but according to scientific researchers, there are more than a million species in the world. General characteristics bacteria makes it possible to determine their role in the biosphere, as well as to study the structure, types and classification of the kingdom of bacteria.

Habitats

The simplicity of the structure and the speed of adaptation to environmental conditions helped the bacteria spread into wide range of our planet. They exist everywhere: water, soil, air, living organisms - all this is the most acceptable habitat for prokaryotes.

Bacteria were found both at the south pole and in geysers. They are found on the ocean floor, as well as in the upper layers of the Earth's air envelope. Bacteria live everywhere, but their number depends on favorable conditions. For example, a large number of bacterial species live in open water bodies, as well as soil.

Structural features

A bacterial cell is distinguished not only by the fact that it does not have a nucleus, but also by the absence of mitochondria and plastids. The DNA of this prokaryote is located in a special nuclear zone and has the appearance of a nucleoid closed in a ring. In bacteria, the cell structure consists of a cell wall, capsule, capsule-like membrane, flagella, pili and cytoplasmic membrane. The internal structure is formed by cytoplasm, granules, mesosomes, ribosomes, plasmids, inclusions and nucleoid.

The cell wall of a bacterium performs the function of defense and support. Substances can flow freely through it due to permeability. This shell contains pectin and hemicellulose. Some bacteria secrete a special mucus that can help protect against drying out. Mucus forms a capsule - a polysaccharide chemical composition. In this form, the bacterium can tolerate even very high temperatures. It also performs other functions, such as adhesion to any surfaces.

On the surface of the bacterial cell there are thin protein fibers called pili. There may be a large number of them. Pili help the cell pass on genetic material and also ensure adhesion to other cells.

Under the plane of the wall there is a three-layer cytoplasmic membrane. It guarantees the transport of substances and also plays a significant role in the formation of spores.

The cytoplasm of bacteria is 75 percent made from water. Composition of the cytoplasm:

• Fishsomes;
• mesosomes;
• amino acids;
• enzymes;
• pigments;
• sugar;
• granules and inclusions;
• nucleoid.

Metabolism in prokaryotes is possible both with and without the participation of oxygen. Most of them eat ready-made nutrients organic origin. Very few species are capable of synthesizing organic substances from inorganic ones. These are blue-green bacteria and cyanobacteria, which played a significant role in the formation of the atmosphere and its saturation with oxygen.

Reproduction

In conditions favorable for reproduction, it is carried out by budding or vegetatively. Asexual reproduction occurs in the following sequence:

1. The bacterial cell reaches its maximum volume and contains the necessary supply of nutrients.
2. The cell lengthens and a septum appears in the middle.
3. Nucleotide division occurs inside the cell.
4. The main and separated DNA diverge.
5. The cell divides in half.
6. Residual formation of daughter cells.

With this method of reproduction, there is no exchange of genetic information, so all daughter cells will be an exact copy of the mother.

The process of bacterial reproduction under unfavorable conditions is more interesting. Scientists learned about the ability of sexual reproduction of bacteria relatively recently - in 1946. Bacteria do not have division into female and reproductive cells. But their DNA is heterogeneous. When two such cells approach each other, they form a channel for the transfer of DNA, and an exchange of sites occurs - recombination. The process is quite long, the result of which is two completely new individuals.

Most bacteria are very difficult to see under a microscope because they do not have their own color. Few varieties are purple or green in color due to their bacteriochlorophyll and bacteriopurpurin content. Although if we look at some colonies of bacteria, it becomes clear that they release colored substances into their environment and acquire a bright color. In order to study prokaryotes in more detail, they are stained.

Classification

Classification of bacteria can be based on indicators such as:

• Form
• mode of transportation;
• method of obtaining energy;
• waste products;
• degree of danger.

Bacteria symbionts live in community with other organisms.

Bacteria saprophytes live on already dead organisms, products and organic waste. They promote the processes of rotting and fermentation.

Rotting cleanses nature of corpses and other organic waste. Without the process of decay there would be no cycle of substances in nature. So what is the role of bacteria in the cycle of substances?

Rotting bacteria are an assistant in the process of breaking down protein compounds, as well as fats and other compounds containing nitrogen. After carrying out a complex chemical reaction, they break the bonds between the molecules of organic organisms and capture protein molecules and amino acids. When the molecules break down, they release ammonia, hydrogen sulfide and other harmful substances. They are poisonous and can cause poisoning in people and animals.

Rotting bacteria multiply quickly in conditions favorable to them. Since these are not only beneficial bacteria, but also harmful ones, in order to prevent premature rotting of products, people have learned to process them: drying, pickling, salting, smoking. All these treatment methods kill bacteria and prevent them from multiplying.

Fermentation bacteria with the help of enzymes are able to break down carbohydrates. People noticed this ability back in ancient times and still use such bacteria to make lactic acid products, vinegars, and other food products.

Bacteria, working together with other organisms, do very important chemical work. It is very important to know what types of bacteria there are and what benefits or harm they bring to nature.

Meaning in nature and for humans

The great importance of many types of bacteria has already been noted above (in the processes of decay and various types fermentation), i.e. fulfilling a sanitary role on Earth.

Bacteria also play a huge role in the cycle of carbon, oxygen, hydrogen, nitrogen, phosphorus, sulfur, calcium and other elements. Many types of bacteria contribute to the active fixation of atmospheric nitrogen and convert it into organic form, helping to increase soil fertility. Especially important have those bacteria that decompose cellulose, which are the main source of carbon for the life of soil microorganisms.

Sulfate-reducing bacteria are involved in the formation of oil and hydrogen sulfide in medicinal mud, soils and seas. Thus, the layer of water saturated with hydrogen sulfide in the Black Sea is the result of the vital activity of sulfate-reducing bacteria. The activity of these bacteria in soils leads to the formation of soda and soda salinization of the soil. Sulfate-reducing bacteria convert nutrients in rice plantation soils into a form that becomes available to the roots of the crop. These bacteria can cause corrosion of metal underground and underwater structures.

Thanks to the vital activity of bacteria, the soil is freed from many products and harmful organisms and is saturated with valuable nutrients. Bactericidal preparations are successfully used to combat many types of insect pests (corn borer, etc.).

Many types of bacteria are used in various industries to produce acetone, ethyl and butyl alcohols, acetic acid, enzymes, hormones, vitamins, antibiotics, protein-vitamin preparations, etc.

Without bacteria, the processes of tanning leather, drying tobacco leaves, producing silk, rubber, processing cocoa, coffee, soaking hemp, flax and other bast-fiber plants, sauerkraut, and cleaning are impossible. waste water, metal leaching, etc.

Among bacteria industrial application since ancient times have lactic acid bacteria of the genera Lactobacillus, Streptococcus when receiving fermented milk products. Cocci have a round, oval shape with a diameter of 0.5-1.5 microns, arranged in pairs or in chains of different lengths. The sizes of rod-shaped bacteria or united in 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, inactive acid former, used for fermenting cream in the production of sour cream.

Acidophilus bacillus Lactobacillus acidophilus form long chains of rod-shaped cells; when fermented, they accumulate up to 2.2% lactic acid and antibiotic substances that are active against pathogens of intestinal diseases. Based on them, medical biological products are prepared for the prevention and treatment of gastrointestinal diseases of agricultural animals.

Lactic acid sticks L. plantatum have cells linked in pairs or in chains. Fermentation agents during fermentation of vegetables and ensiling of feed. L. brevis ferment sugars when pickling cabbage and cucumbers, forming acids, ethanol, CO 2.

Non-sporeless, 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 ripening of rennet cheeses. Some types of propionic acid bacteria are used to produce vitamin B12.

Spore-forming bacteria of the family Bacilloceae sort of Clostridium are causative agents of butyric acid 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, silty sediments of water bodies, accumulations of decomposing organic residues, food products.

These minerals are used in the production of butyric acid, which has unpleasant smell, unlike its broadcasts:

Methyl ether – apple scent;

Ethyl - pear;

Amyl - pineapple.

They are used as flavoring agents.

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

Acetic acid bacteria – nonsporeless 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

Sticks of sorts Acetobacter– peritrichs, 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 is the basis for the production of vinegar. The spontaneous development of acetic acid bacteria in wine, beer, kvass leads to their spoilage - souring, clouding. These bacteria form dry wrinkled films, islands or a ring near the walls of the vessel on the surface of liquids.

A common type of damage is rotting 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 rod. The spores are heat-resistant, oval. Cells are sensitive to an acidic environment and high NaCl content.

Bacteria genusPseudomonus – aerobic motile rods with polar flagella, do not form spores, gram-. Some species synthesize pigments, they are called fluorescent pseudomonas, some are cold-resistant, and cause spoilage of protein products in refrigerators. Pathogens of bacteriosis of cultivated plants.

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

Great value Nitrifying, denitrifying, and nitrogen-fixing bacteria play a role in soil formation. These are mainly non-spore-forming cells. They are grown in artificial conditions and applied in the form of soil fertilizers.

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

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

Microorganisms and their metabolic products are currently widely used in industry, agriculture, and medicine.

History of the use of microorganisms

As early as 1000 BC, the Romans, Phoenicians and other early civilizations extracted copper from mine waters or waters that seeped through ore bodies. In the 17th century Welsh in England (County Wales) and in the 18th century. The Spaniards at the Rio Tinto mine used this "leaching" process to extract copper from the minerals containing it. These ancient miners had no idea that bacteria played an active role in such metal extraction processes. This process, known as bacterial leaching, is now used on a large scale throughout the world to extract copper from low-grade ores containing trace amounts of this and other valuable metals. Bioleaching is also used (though less widely) to release uranium. Numerous studies have been carried out on the nature of the organisms involved in metal leaching processes, their biochemical properties and potential applications in this area. The results of these studies show, in particular, that bacterial leaching can be widely used in the mining industry and, in all likelihood, can fully meet the need for energy-saving, environmentally friendly technologies.

Somewhat less known, but equally important, is the use of microorganisms in the mining industry to extract metals from solutions. Some advanced technologies already include biological processes for obtaining metals in a dissolved state or in the form of solid particles “from washing water remaining from ore processing. The ability of microorganisms to accumulate metals has long been known, and enthusiasts have long dreamed of using microbes to extract valuable metals from seawater. The studies carried out dispelled some hopes and largely determined the areas of application of microorganisms. Metal-assisted recovery remains a promising method for low-cost treatment of metal-contaminated industrial wastewater and economical recovery of valuable metals.

It has long been known about the ability of microorganisms to synthesize polymer compounds; in fact, most cell components are polymers. However, today less than 1% of the total amount of polymer materials is produced by the microbiological industry; the remaining 99% comes from petroleum. So far, biotechnology has not had a decisive influence on polymer technology. Perhaps in the future, with the help of microorganisms, it will be possible to create new materials for special purposes.

Another important aspect of the use of microorganisms in chemical analysis should be noted - the concentration and isolation of trace elements from dilute solutions. By consuming and assimilating microelements in the process of life, microorganisms can selectively accumulate some of them in their cells, purifying nutrient solutions from impurities. For example, molds are used for selective precipitation of gold from chloride solutions.

Modern Applications

Microbial biomass is used as livestock feed. The microbial biomass of some crops is used in the form of various starter cultures, which are used in food industry. So is the preparation of bread, beer, wine, spirits, vinegar, fermented milk products, cheeses and many products. Another important area is the use of waste products of microorganisms. Based on the nature of these substances and their importance for the producer, waste products can be divided into three groups.

1 group- These are large molecules with molecular weight. This includes a variety of enzymes (lipases, etc.) and polysaccharides. Their use is extremely wide - from the food and textile industries to the oil industry.

2nd group- these are primary methanobolites, which include substances necessary for the growth and development of the cell itself: amino acids, organic acids, vitamins and others.

3 group- secondary methanobolites. These include: antibiotics, toxins, alkaloids, growth factors, etc. An important area of ​​biotechnology is the use of microorganisms as biotechnical agents for the transformation or transformation of certain substances, purification of water, soil or air from pollutants. Microorganisms also play a role in oil production. important role. Traditional way No more than 50% of the oil is recovered from an oil reservoir. The waste products of bacteria, accumulating in the formation, contribute to the displacement of oil and its more complete release to the surface.

The huge role of microorganisms in creating, maintaining and preserving soil fertility. They take part in the formation of soil humus - humus. Used to increase crop yields.

IN recent years Another fundamentally new direction of biotechnology began to develop - cell-free biotechnology.

Selection of microorganisms is based on the fact that microorganisms bring enormous benefits in industry, agriculture, animal and plant life.

Other Applications

In medicine

Traditional methods of vaccine production are based on the use of weakened or killed pathogens. Currently, many new vaccines (for example, for the prevention of influenza, hepatitis B) are obtained using genetic engineering methods. Antiviral vaccines are obtained by introducing into the microbial cell the genes of viral proteins that exhibit the greatest immunogenicity. When cultivated, such cells synthesize large number viral proteins that are subsequently included in vaccine preparations. The production of viral proteins in animal cell cultures based on recombinant DNA technology is more efficient.

In oil production:

In recent years, methods for increasing oil recovery using microorganisms have been developed. Their prospects are associated, first of all, with ease of implementation, minimal capital intensity and environmental safety. In the 1940s, many oil-producing countries began research on the use of microorganisms to stimulate flow in production wells and restore the injectivity of injection wells.

In food and chemical industry:

The most well-known industrial products of microbial synthesis include: acetone, alcohols (ethanol, butanol, isopropanol, glycerol), organic acids (citric, acetic, lactic, gluconic, itaconic, propionic), flavorings and substances that enhance odors (monosodium glutamate). The demand for the latter is constantly increasing due to the tendency to consume low-calorie and plant-based foods to add variety to the taste and smell of food. Aromatics plant origin can be produced by expressing plant genes in microbial cells.