Use of microorganisms in medicine. Application of microorganisms in medicine, agriculture; benefits of probiotics

Practical use of bacteria in food production

Among bacteria, lactic acid bacteria of the genus 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 in 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 farm 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 o/o are used in the production of butyric acid, which has an unpleasant odor, in contrast to its esters:

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 movable gram+ rods Clostridium botulinum. The spores give the appearance of a racket. The exotoxin of these bacteria affects the central nervous and cardiovascular systems (signs: visual impairment, speech impairment, paralysis, respiratory failure).

Nitrifying, denitrifying, and nitrogen-fixing bacteria play a great 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 are widely used in the food industry, households, and the microbiological industry to produce amino acids, enzymes, organic acids, vitamins, etc. Classic microbiological production includes winemaking, brewing, making bread, lactic acid products and food vinegar. For example, winemaking, brewing and the production of yeast dough are impossible without the use of yeast, which is widespread in nature.

The history of industrial production of yeast began in Holland, where the first factory producing yeast was founded in 1870. The main type of product was compressed yeast with a moisture content of about 70%, which could be stored for only a few weeks. Long-term storage was impossible, since the pressed yeast cells remained alive and retained their activity, which led to their autolysis and death. One of the methods for industrially preserving yeast is drying. In dry yeast, at low humidity, the yeast cell is in an anabiotic state and can persist for a long time. The first dry yeast appeared in 1945. In 1972, the second generation of dry yeast, the so-called instant yeast, appeared. Since the mid-1990s, a third generation of dry yeast has emerged: baker's yeast Saccharomyces cerevisiae, which combine the benefits of instant yeast with a highly concentrated complex of specialized baking enzymes in one product. This yeast not only improves the quality of bread, but also actively resists the process of staling.

Baker's yeast Saccharomyces cerevisiae are also used in the production of ethyl alcohol.

Winemaking uses many different races of yeast to produce a unique brand of wine with unique qualities.

Lactic acid bacteria are involved in the preparation of foods such as sauerkraut, pickles, pickled olives and many other pickled foods.

Lactic acid bacteria convert sugar into lactic acid, which protects food products from putrefactive bacteria.

With the help of lactic acid bacteria, a wide range of lactic acid products, cottage cheese, and cheese are prepared.

However, many microorganisms play a negative role in human life, being pathogens of diseases in humans, animals and plants; they can cause food spoilage, destruction of various materials, etc.

To combat such microorganisms, antibiotics were discovered - penicillin, streptomycin, gramicidin, etc., which are metabolic products of fungi, bacteria and actinomycetes.

Microorganisms provide humans with the necessary enzymes. Thus, amylase is used in the food, textile, and paper industries. Protease causes the breakdown of proteins in various materials. In the East, protease from mushrooms was used several centuries ago to make soy sauce. Currently, it is used in the production of detergents. When canning fruit juices, an enzyme such as pectinase is used.

Microorganisms are used for wastewater treatment and food processing waste. The anaerobic decomposition of organic matter in waste produces biogas.

In recent years, new production facilities have appeared. Carotenoids and steroids are obtained from mushrooms.

Bacteria synthesize many amino acids, nucleotides and other reagents for biochemical research.

Microbiology is a rapidly developing science, the achievements of which are largely related to the development of physics, chemistry, biochemistry, molecular biology, etc.

To successfully study microbiology, knowledge of the listed sciences is required.

This course focuses primarily on food microbiology. Many microorganisms live on the surface of the body, in the intestines of humans and animals, on plants, on food products and on all objects around us. Microorganisms consume a wide variety of foods and adapt extremely easily to changing living conditions: heat, cold, lack of moisture, etc. They multiply very quickly. Without knowledge of microbiology, it is impossible to competently and effectively manage biotechnological processes, maintain high quality food products at all stages of its production and prevent the consumption of products containing pathogens of foodborne illnesses and poisoning.

It should be especially emphasized that microbiological studies of food products, not only from the point of view of technological features, but also, no less important, from the point of view of their sanitary and microbiological safety, are the most complex object of sanitary microbiology. This is explained not only by the diversity and abundance of microflora in food products, but also by the use of microorganisms in the production of many of them.

In this regard, in microbiological analysis of food quality and safety, two groups of microorganisms should be distinguished:

– specific microflora;

– nonspecific microflora.

Specific– these are cultural races of microorganisms that are used to prepare a particular product and are an essential link in the technology of its production.

This microflora is used in the technology of producing wine, beer, bread, and all fermented milk products.

Nonspecific are microorganisms that enter food products from the environment, contaminating them. Among this group of microorganisms, saprophytic, pathogenic and opportunistic microorganisms are distinguished, as well as microorganisms that cause food spoilage.

The degree of contamination depends on many factors, which include the correct procurement of raw materials, their storage and processing, compliance with technological and sanitary regimes for the production of products, their storage and transportation.

Bacteria play a huge role in both the biosphere and human life. Bacteria take part in many biological processes, especially in the circulation of substances in nature. Significance for the biosphere:

© Many bacteria can fix atmospheric nitrogen. Moreover, azotobacter, free-living in the soil, fixes nitrogen independently of plants, and nodule bacteria They show their activity only in symbiosis with the roots of higher plants (mainly legumes); thanks to these bacteria, the soil is enriched with nitrogen and plant productivity increases.

© Bacteria are not only decomposers, but also producers (creators) of organic matter, which must be used by other organisms. Compounds formed as a result of the activity of bacteria of one type can serve as a source of energy for bacteria of another type.

However, bacteria regulate the gas composition of the atmosphere.

Some substances formed during the life of bacteria are also important for humans. Their meaning is as follows:

A negative role is played by pathogenic bacteria that cause diseases of plants, animals and humans.

Many bacteria cause food spoilage and release toxic substances.

Bacteria, characteristics and significance for humans

Structure

Bacteria are very small living organisms. They can only be seen under a microscope with very high magnification. All bacteria are unicellular. The internal structure of a bacterial cell is not similar to plant and animal cells. They have neither a nucleus nor plastids. Nuclear matter and pigments are present, but in a “sprayed” state. The form is varied.

The bacterial cell is covered with a special dense shell - a cell wall, which performs protective and supporting functions, and also gives the bacterium a permanent, characteristic shape. The cell wall of a bacterium resembles the wall of a plant cell. It is permeable: through it, nutrients freely pass into the cell, and metabolic products exit into the environment. Often, bacteria produce an additional protective layer of mucus on top of the cell wall - a capsule. The thickness of the capsule can be many times greater than the diameter of the cell itself, but it can also be very small. The capsule is not an essential part of the cell; it is formed depending on the conditions in which the bacteria find themselves. It protects the bacteria from drying out.

On the surface of some bacteria there are long flagella (one, two or many) or short thin villi. The length of the flagella can be many times greater than the size of the body of the bacterium.

Bacteria move with the help of flagella and villi.

Inside the bacterial cell there is dense, immobile cytoplasm. It has a layered structure, there are no vacuoles, therefore various proteins (enzymes) and reserve nutrients are located in the substance of the cytoplasm itself. Bacterial cells do not have a nucleus. A substance carrying hereditary information is concentrated in the central part of their cell. Bacteria, - nucleic acid - DNA. But this substance is not formed into a nucleus.

The internal organization of a bacterial cell is complex and has its own specific characteristics. The cytoplasm is separated from the cell wall by the cytoplasmic membrane. In the cytoplasm there is a main substance, or matrix, ribosomes and a small number of membrane structures that perform a variety of functions (analogues of mitochondria, endoplasmic reticulum, Golgi apparatus). The cytoplasm of bacterial cells often contains granules of various shapes and sizes. The granules may be composed of compounds that serve as a source of energy and carbon. Droplets of fat are also found in the bacterial cell.

Education dispute

Spores form inside the bacterial cell. During the process of sporulation, the bacterial cell undergoes a number of biochemical processes. The amount of free water in it decreases and enzymatic activity decreases. This ensures the resistance of the spores to unfavorable environmental conditions (high temperature, high salt concentration, drying, etc.). Sporulation is characteristic of only a small group of bacteria. Spores are an optional stage in the life cycle of bacteria. Sporulation begins only with a lack of nutrients or accumulation of metabolic products. Bacteria in the form of spores can remain dormant for a long time. Bacterial spores can withstand prolonged boiling and very long freezing. When favorable conditions occur, the spore germinates and becomes viable. Bacterial spores are an adaptation to survival in unfavorable conditions. Bacterial spores serve to survive unfavorable conditions. They are formed from the interior of the cell contents. At the same time, a new, denser shell is formed around the spore. Spores can tolerate very low temperatures (up to - 273 ° C) and very high ones. Spores are not killed by boiling water.

Nutrition

Many bacteria have chlorophyll and other pigments. They carry out photosynthesis, like plants (cyanobacteria, purple bacteria). Other bacteria obtain energy from inorganic substances - sulfur, iron compounds and others, but the source of carbon, as in photosynthesis, is carbon dioxide.

Reproduction

Bacteria reproduce by dividing one cell into two. Having reached a certain size, the bacterium divides into two identical bacteria. Then each of them begins to feed, grows, divides, and so on. After cell elongation, a transverse septum gradually forms, and then the daughter cells separate; In many bacteria, under certain conditions, after dividing, cells remain connected in characteristic groups. In this case, depending on the direction of the division plane and the number of divisions, different shapes arise. Reproduction by budding occurs as an exception in bacteria.

Under favorable conditions, cell division in many bacteria occurs every 20-30 minutes. With such rapid reproduction, the offspring of one bacterium in 5 days is capable of forming a mass that can fill all seas and oceans. A simple calculation shows that 72 generations (720,000,000,000,000,000,000 cells) can be formed per day. If converted into weight - 4720 tons. However, this does not happen in nature, since most bacteria quickly die under the influence of sunlight, drying, lack of food, heating to 65-100ºC, as a result of struggle between species, etc.

The role of bacteria in nature. Distribution and ecology

Bacteria are distributed everywhere: in water bodies, air, soil. There are fewer of them in the air (but not in crowded places). In river waters there can be up to 400,000 per 1 cm3, and in soil - up to 1,000,000,000 per 1 g. Bacteria have different attitudes towards oxygen: for some it is necessary, for others it is destructive. For most bacteria, temperatures between +4 and +40 °C are most favorable. Direct sunlight kills many bacteria.

Found in huge numbers (the number of their species reaches 2500), bacteria play an extremely important role in many natural processes. Together with fungi and soil invertebrates, they participate in the processes of decomposition of plant residues (falling leaves, branches, etc.) to humus. The activity of saprophytic bacteria leads to the formation of mineral salts, which are absorbed by plant roots. Nodule bacteria living in the tissues of moth roots, as well as some free-living bacteria, have a remarkable ability to assimilate atmospheric nitrogen, which is inaccessible to plants. Thus, bacteria participate in the cycle of substances in nature.

Soil microflora. The number of bacteria in the soil is extremely large - hundreds of millions and billions of individuals per gram. There are much more of them in soil than in water and air. The total number of bacteria in soils changes. The number of bacteria depends on the type of soil, their condition, and the depth of the layers. On the surface of soil particles, microorganisms are located in small microcolonies (20-100 cells each). They often develop in the thickness of clots of organic matter, on living and dying plant roots, in thin capillaries and inside lumps. The soil microflora is very diverse. Here there are different physiological groups of bacteria: putrefaction bacteria, nitrifying bacteria, nitrogen-fixing bacteria, sulfur bacteria, etc. among them there are aerobes and anaerobes, spore and non-spore forms. Microflora is one of the factors in soil formation. The area of development of microorganisms in the soil is the zone adjacent to the roots of living plants. It is called the rhizosphere, and the totality of microorganisms contained in it is called the rhizosphere microflora.

Microflora of water bodies. Water is a natural environment where microorganisms develop in large numbers. The bulk of them enters the water from the soil. A factor that determines the number of bacteria in water and the presence of nutrients in it. The cleanest waters are from artesian wells and springs. Open reservoirs and rivers are very rich in bacteria. The largest number of bacteria is found in the surface layers of water, closer to the shore. As you move away from the shore and increase in depth, the number of bacteria decreases. Clean water contains 100-200 bacteria per ml, and polluted water contains 100-300 thousand or more. There are many bacteria in the bottom sludge, especially in the surface layer, where the bacteria form a film. This film contains a lot of sulfur and iron bacteria, which oxidize hydrogen sulfide to sulfuric acid and thereby prevent fish from dying. There are more spore-bearing forms in silt, while non-spore-bearing forms predominate in water. In terms of species composition, the microflora of water is similar to the microflora of soil, but there are also specific forms. By destroying various waste that gets into the water, microorganisms gradually carry out the so-called biological purification of water.

Air microflora. The microflora of the air is less numerous than the microflora of soil and water. Bacteria rise into the air with dust, can remain there for some time, and then settle on the surface of the earth and die from lack of nutrition or under the influence of ultraviolet rays. The number of microorganisms in the air depends on the geographical zone, terrain, time of year, dust pollution, etc. each speck of dust is a carrier of microorganisms. Most bacteria are in the air above industrial enterprises. The air in rural areas is cleaner. The cleanest air is over forests, mountains, and snowy areas. The upper layers of air contain fewer microbes. The air microflora contains many pigmented and spore-bearing bacteria, which are more resistant than others to ultraviolet rays.

Microflora of the human body. The human body, even a completely healthy one, is always a carrier of microflora. When the human body comes into contact with air and soil, various microorganisms, including pathogenic ones (tetanus bacilli, gas gangrene, etc.), settle on clothing and skin. The most frequently exposed parts of the human body are contaminated. E. coli and staphylococci are found on the hands. There are over 100 types of microbes in the oral cavity. The mouth, with its temperature, humidity, and nutrient residues, is an excellent environment for the development of microorganisms. The stomach has an acidic reaction, so the majority of microorganisms in it die. Starting from the small intestine, the reaction becomes alkaline, i.e. favorable for microbes. The microflora in the large intestines is very diverse. Each adult excretes about 18 billion bacteria daily in excrement, i.e. more individuals than people on the globe. Internal organs that are not connected to the external environment (brain, heart, liver, bladder, etc.) are usually free of microbes. Microbes enter these organs only during illness.

The importance of bacteria in human life

Fermentation processes are of great importance; This is what is generally called the decomposition of carbohydrates. So, as a result of fermentation, milk turns into kefir and other products; Ensilage of feed is also fermentation. Fermentation also occurs in the human intestine. Without appropriate bacteria (for example, E. coli), the intestines cannot function normally. Rotting, which is useful in nature, is extremely undesirable in everyday life (for example, spoilage of meat products). Fermentation (for example, souring milk) is not always beneficial. To prevent food from spoiling, they are salted, dried, canned, and kept in refrigerators. This reduces the activity of bacteria.

Pathogenic bacteria

Spores in bacteria, unlike fungal spores, do not serve for reproduction, but serve as an adaptation to endure unfavorable conditions. Each bacterium develops into only one spore. When environmental conditions become suitable, the spore is restored back into a bacterium with normal metabolism.

In the spore state, many bacteria are able to survive critical temperatures (from boiling to deep minus) and remain viable for hundreds of years.

When bacterial spores form, the volume of the cytoplasm decreases due to water loss. The resulting spore is usually smaller and lighter than the bacterium itself.

Spores are easily carried by the wind, which means their formation can be considered not only a protective mechanism, but also a method of dispersal.

Spores in fungi also serve for dispersal, but here their main function is reproduction, which is not the case in prokaryotes.

Disputes can arise in different ways. Most often, so-called endospores are formed. In this case, the cell membrane indents inwards, the cytoplasm with its contents passes there, and the rest of the bacterium turns into a protective layer, which is enclosed in the cell membrane on the outer and inner sides.

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

Ode to bacteria

Their structure is very primitive - most of them are single-celled organisms, which, obviously, have changed little over such a very long time. They are unpretentious and can survive in conditions that are extreme for other organisms (heating up to 90 degrees, freezing, 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.

Oxygen Makers

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 large numbers, produce a huge amount of oxygen entering the atmosphere. This becomes especially relevant in connection with the cutting down of forests that are strategically important for the entire Earth. And some other bacteria produce carbon dioxide, which is necessary for plant respiration. But the role of bacteria in human life and nature is not limited to this. There are several more “types of activity” for which bacteria can safely be given

Orderlies

In nature, one of the functions of bacteria is sanitary. They eat dead cells and organisms, disposing of unnecessary things. It turns out that bacteria act as janitors of sorts for all life on the planet. In science, this phenomenon is called saprotrophy.

Cycle of substances

And another important role is participation on a planetary scale. In nature, all substances pass from organism to organism. Sometimes they are in the atmosphere, sometimes in the soil, supporting a large-scale cycle. Without bacteria, these components could concentrate 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 is a product known to people for a long time. But its long-term storage has become possible only recently with the invention of preservation methods and refrigeration units. And since the dawn of cattle breeding, people have unknowingly used bacteria to ferment milk and produce fermented milk products that have a longer shelf life than milk itself. For example, dry kefir could be stored for months and used as nourishing food during long treks 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 cannot be done 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 products that are produced using these organisms. These are sauerkraut, pickled (barrel) cucumbers, pickles loved by many and other products.

The world's best neighbors

Bacteria are 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 humans. For example, bifidobacteria strengthen our immunity, increasing 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 equally invaluable.

Production of necessary substances

Scientists were able to work with bacteria in such a way that they began to secrete substances necessary for humans. Often these substances are medications. So the therapeutic role of bacteria in human life is also great. Some modern medicines are produced 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. For example, in recent decades, biogas production in some countries has reached serious proportions.

Negative and positive role of bacteria

But these microscopic single-celled organisms can be not only human assistants and coexist with him in complete harmony and peace. The biggest danger they pose is infectious. Taking residence 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 and cholera. Less dangerous are tonsillitis 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 try to “keep under control” these harmful microorganisms.

Food spoilage by bacteria

If the meat is rotten and the soup is sour, this is probably the work of bacteria! They start there and actually “eat” these products before us. After which these dishes no longer represent nutritional value for humans. All that's left to do is throw it away!

Results

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