Biotechnology today is a multidisciplinary and integrated industry. It includes:
• traditional biotechnology based on the implementation of fermentation processes;
• modern biotechnology implemented in the processes of microbiological synthesis, genetic and cellular engineering, engineering enzymology (protein engineering).
The advantages of biological processes include the fact that they use renewable raw materials (biomass), proceed under mild conditions (at room temperature, normal pressure), with fewer technological stages (steps), their waste is available for further processing. Especially beneficial is the use of biotechnological processes (economically and technologically) in the case of the production of relatively expensive, but low-tonnage products.
Fermentation (fermentation) is the process of splitting organic substances, mainly carbohydrates, into simpler compounds under the influence of microorganisms or enzymes isolated from them. This process can be carried out both with the participation of oxygen (aerobic process), and without the participation of oxygen (anaerobic process).
Various types of fermentation are known. They are classified either by substrates, which are decomposed (for example, pectin fermentation of fiber, etc.), or, more often, by final products: alcohol, lactic acid, propionic acid, methane fermentation, etc., proceeding mainly anaerobically.
As mentioned above, one of the main substrates of many types of fermentation is carbohydrates, which are split in stages under anaerobic conditions by enzymes.
Alcoholic fermentation is carried out mainly with the help of yeast and bacteria and ends with the formation of ethyl alcohol.
This type of fermentation proceeds in several stages and is used for the industrial production of ethanol (mainly from rye grain) – for alcoholic beverages, in winemaking, brewing and in the preparation of dough in the baking industry.
In the presence of oxygen, alcohol fermentation slows down or stops altogether. A modified type of alcoholic fermentation is glycerin fermentation.
Lactic fermentation is caused by lactic acid bacteria. Lactic acid fermentation is of great importance in the production of various dairy products (kefir, yogurt, etc.), fermented vegetables (for example, cabbage), silage of animal feed (in agriculture).
Propionic acid fermentation proceeds under the influence of propionic acid bacteria. It is used in the dairy industry to make many hard cheeses.
Oil-acidic fermentation leads to spoilage of food products, swelling of cheese and cans of canned food. Previously, it was used to obtain butyric acid, butyl alcohol and acetone.
Methane fermentation begins with the decomposition of complex substances, such as cellulose, to one- or two-carbon, which is carried out by microorganisms living in symbiosis (cohabitation) with methane-forming bacteria. The latter also synthesize methane.