Everything is so harmoniously arranged by nature that everyone in this world has its own place and is engaged in those functions that are assigned to it, whether it is the crown of nature - an incredibly complex human or the most microscopic organism. Everyone plays a role to make our world better. This also applies to various bacteria, which, according to the great plan of the creator of the world, bring people not only benefit, but also certain harm. Consider what thermophilic lactic acid bacteria are and what their place is in our lives. Are they useful or harmful?
Features and essence
A whole army of various microorganisms lives on our planet, not visible to the eye, but very active and not always useful. One of these beneficial micro-formations is the thermophilic bacterium. The bacterium lives in hot springs and multiplies at fairly high temperatures - above 45 degrees. Entire colonies of these microorganisms have been identified in different geothermal zones of our planet, such as the waters of hot natural springs. Thermophilic bacteria survive due to the presence of special enzymes in them that can function at high temperatures. For them, the most favorable temperature regime is a corridor of 50-65 degrees. Under such conditions, bacteria can feel comfortable and multiply freely.
Many would like to know at what temperature thermophilic bacteria die to control their number. In this regard, I would like to note that scientists have not yet been able to obtain accurate data on this. At the present stage of the development of science, it is only known that the maximum temperature index for thermophiles is 68-75 degrees. However, this does not mean that bacteria die during such heating - deviation from the optimal mode makes their life less comfortable and intense, slows down cell growth and reduces the rate of metabolic processes.
Is it possible to kill bacteria? What is detrimental to them?
For thermophilic bacteria to die, a much greater excess of the upper threshold is needed. Today, scientists were able to establish that the highest currently known temperature at which these microorganisms can live is 122 degrees Celsius. It is not possible to create higher heating in the laboratory. Therefore, it is not yet possible to establish at what temperature thermophilic bacteria die. It is only known that sharp fluctuations in temperature are very detrimental to the life of bacteria: the development of a culture may stop, but whether it dies is a question.
Varieties and their description
Assessing the temperature preferences of microorganisms, they can be divided into three main groups: psychrophilic, mesophilic, and, in fact, thermophilic. All of them are dependent on heat, but differ in terms of temperature conditions.
So, psychrophilic bacteria are the least heat-dependent and prefer a temperature range from zero to +10 degrees. This is the optimal development corridor for them, but they can reproduce at -5 degrees, and at +15.
Next - mesophilic thermophilic bacteria, the comfort zone for which is between 30 and 40 degrees heat. Bacteria may well grow and multiply when the temperature drops to 10 degrees or if it rises to 50 degrees. The optimal level for growth in these organisms is 37 degrees.
And finally, thermophilic bacteria - their active growth is observed when the temperature regime reaches above 50 degrees. Their main distinguishing feature is the accelerated rate of metabolism. According to recent studies, it has been found that, under the influence of temperature, significant changes occur in proteins and lipids, which play a major role in all life processes.
Thermophilic subgroups
A vivid illustration of this are examples of thermophilic bacteria, which are also divided into several independent subgroups:
- Extreme thermophiles with an optimal temperature of 80 degrees with a minimum of 60 and a maximum of 105 degrees.
- Stenothermophiles, or optional, with a range of 55-65 degrees, but show the ability to reproduce even when the temperature drops to 20 degrees. The highest ability to grow is observed at 20-40 degrees.
- Eurythermophiles prefer 37-48 degrees. The peculiarity of obligate thermophiles is that they do not lose their ability to grow at 70 degrees, but do not grow below 40 degrees.
- Thermo-tolerants with an optimal indicator of no higher than 48 degrees, the minimum temperature at which they can grow is 10 degrees, and the maximum is 55-60. They differ from mesophiles at the same optimal temperatures in that, with an increase in the temperature threshold, bacteria continue to grow.
Anaerobic thermophiles
The ability of the rapid growth of thermophilic organisms gives them an excellent opportunity to be used in a variety of areas of life - in industry or in agriculture and even at the household level. At the same time, mesophilic and thermophilic lactic acid bacteria have similar methods of isolation. The difference is observed only in growing temperatures. To establish the exact optimal temperature level, the culture must be passaged for one or two months, or, in other words, re-sow in a certain temperature range.
In nature, many species of thermophilic bacteria are widespread and under various conditions. They love warmth and feel very comfortable in the human stomach, and can also be in animals, plants, soil, water and various other environments that provide favorable temperature conditions for development. Some bacteria require the presence of air for development, others absolutely do not need oxygen. According to this sign of oxygen dependence, thermophilic organisms are divided into aerobic and anaerobic.
Anaerobic include several separate groups:
- Oil acids - during fermentation they produce butyric acid, feed on sugar, pectins, dextrins, and produce acids - acetic and butyric, as well as hydrogen and carbon dioxide. Among the useful properties, the production of acetone, ethyl, butyl and isopropyl alcohols can be distinguished. It occurs in thermophilic and mesophilic forms.
- Cellulose live in river silt, compost, plant debris. These thermophilic bacteria for compost are ideal and are widely used in the agricultural field. Being in the soil or humus, these bacteria gain activity at 60-65 degrees. There is also a mesophilic form - Omelyansky stick. These bacteria with the help of a special enzyme decompose cellulose, releasing carbon dioxide, hydrogen, ethyl alcohol, a number of acids - formic, acetic, fumaric, lactic and other organic acids.
- Methane-forming live in the same place as cellulose, and are cultivated there. In this group, species such as methanobacterium and methanobacillus are the most studied. They are not capable of sporulation, and their benefit is the ability to produce antibiotics, vitamins, enzymes, using wastewater and household waste for nutrition.
- Desulphurizing agents are most often located next to cellulosic ones and live off the reduction of sulfates. They have oval spores that are located closer to one of the ends of the bacillus coli - terminal or subterminal.
- Lactic acid is a special large group of bacteria that live in milk. These thermophilic lactic acid bacteria can be both beneficial to humans and very harmful. Some of their species can synthesize special aromatic substances. It is they, after exposure to milk, that give cottage cheese or cream a pleasant taste and aroma. Such thermophilic lactic acid bacteria are facultative anaerobic, therefore, they can optimally reproduce in the absence of oxygen or in an environment where there is a large deficit of oxygen.
Lactic acid
Lactic acid bacteria are divided into cocci and sticks. The first ones consist of several cells connected in a chain - streptococci and have homo- and heterogeneous fermentation. Homogenous streptococci ferment sugar, which is in milk, which allows you to cook live yogurt. Heterofermentative also emit aromatic substances such as diacetin and cytoin. Cells of their round or oval shape, stain well according to the Gram and do not form spores and capsules. They are aerotolerant and can exist in the presence of air. However, they lack the ability to perform aerobic respiration, and they prefer to continue the process of lactic fermentation familiar to them. In order to eat, they need a lot of vitamins, proteins, organic acids. In milk, bacteria cause coagulation, the formation of a dense, even clot with a small amount of serum. It is thanks to the aromatic forming lactic streptococci in the cheese that seductive vesicles with a characteristic odor and low ability to form acids appear. Cocci have high alcohol resistance, and they need high acidity.
Lactic acid sticks
Lactobacillus coli - they are also called lactobacilli - can be either single or paired. Most often, acidophilic lactobacilli are used, especially the Bulgarian stick, which is part of the starter cultures and makes it possible to produce tasty and healthy yogurt. Streptobacteria and beta bacteria are also popular in the dairy industry. These organisms are completely motionless and do not form spores or capsules; they are stained well according to Gram.
Lactic acid thermophiles are optional anaerobes. They can become monoenzymatic, have a high rate of acid formation, or areenzymatic with the ability to process fructose in parallel, resulting in the formation of mannitol hexahydrate, acetates, lactates, and carbon dioxide. Proteins are rather poorly processed; therefore, in order to grow, they require the presence of amino acids in the medium. Some sticks have the ability to produce catalase - an enzyme that breaks down hydrogen peroxide, or acetaldehyde, which gives the smell and taste of cheese.
Heat-resistant lactic acid sticks can survive in milk during pasteurization at a temperature of 85-90 degrees. They are very resistant to disinfecting agents and thus bring considerable harm to food industry enterprises. They are antagonists of E. coli. They are in sourdough or slightly pasteurized milk.
Thermophiles that can't breathe without oxygen
Aerobic thermophiles that cannot breathe without oxygen are also divided into two independent groups:
- Extremely thermophilic - Gram-negative sticks incapable of movement, which are related to obligate bacteria, whose growth occurs at an optimum temperature of 70 degrees. When the temperature rises, the sticks are converted into thin threads. They live en masse in hot water springs and nearby soil.
- Spore-forming forms are similar to mesophilic. They live and spread in well-loosened soil or aerated waters.
Having examined all these types of microorganisms, it should be noted that the appearance of thermophilic bacteria is their aromorphosis into the habitat. Like other living organisms, bacteria can also perfectly adapt to changes in environmental conditions during their evolution. At the same time, they significantly increase the level of their organization and acquire new abilities.
Benefit and harm
What are the harms and benefits of thermophilic bacteria? Lactic acid sticks, used in the food industry, bring man undoubted benefits. As part of various starter cultures, they produce tasty and healthy lactic acid products that have a very positive effect on all systems of the human body, help regulate metabolic processes, normalize the digestive tract and in every way contribute to protecting the body from various putrefactive bacteria, purifying it from accumulated toxins and toxins. In addition to improving the composition of microflora, thermophilic bacteria calm the nervous system, inhibit the action of antibiotics and increase immunity.
In addition to the food industry, this type of bacteria is used quite widely in the pharmacological and cosmetic fields. Various probiotics are made on their basis, as well as cosmetics that give the skin well-being and firmness, and are also used to whiten and restore it. Masks from live yogurt can work wonders.
Thermophilic and mesophilic bacteria that live in soil and compost help to process organic matter, fertilizing the soil for good plant growth. The emitted methane can be successfully used for heating residential buildings and industrial facilities. With such a huge scale of benefits, the small damage that thermophilic sticks cause to food industry enterprises is offset by the effects of bactericidal drugs and constant monitoring of food processing equipment.
Conclusion
In this article, we gave the basic concepts of such a large and poorly studied class as bacteria. From the above material it follows that thermophilic bacteria are already widely used by humans for their own benefit. But this process is far from complete, and many more pleasant and useful discoveries await us.