GENERAL MICROBIOLOGY - T.P. Pyrog - 2004

22. MICROORGANISMS AS OBJECTS OF BIOTECHNOLOGY

22.2. BIOMASS-BASED PREPARATIONS

22.2.3. Protein Products

According to data from the Food and Agriculture Organization OF THE United Nations (1996), the global dietary protein deficit is approximately 10 million tons per year, while the overall shortage of other nutritional components exceeds 80 million tons. It is widely recognized that microbial synthesis technologies hold significant promise for bridging this protein gap. Notably, the USA and several other countries have approved The Use of 10 different Yeast biomasses as food additives.

Baker's yeast and biomass production. The primary objective of manufacturing baker's yeast is to obtain yeast Cells capable of rapidly producing carbon dioxide in dough. However, this process can also be viewed as a specialized method for biomass accumulation. Since baker's yeast is added to flour at a concentration of 1%, it serves as a significant source of microbial biomass in Human Nutrition. In Western Europe, the average person consumes about 2 g of yeast protein per week through their diet. Although yeast exhibits no toxic effects, it does contain a relatively high concentration of Nucleic Acids. A high nucleic acid intake can elevate uric acid levels in The Human Body, potentially leading to Gout.

Spirulina biomass. Recently, particular attention has been focused on novel, nontraditional sources of BIOLOGICALLY ACTIVE SUBSTANCES used as dietary supplements. Microalgae occupy a unique position among the producers of such compounds, most notably Spirulina platensis, which belongs to the cyanobacteria. In addition to a complex of valuable biologically active compounds, spirulina can synthesize hormone-like iodine-containing compounds—thyroxine and triiodothyronine—which are rapidly and efficiently assimilated by the human body. Therefore, spirulina can serve as an additional source of highly bioavailable iodine.

Protein-vitamin concentrates. In livestock and poultry farming, Protein deficiency leads to feed overconsumption and health issues in animals. The key indicator of the biological (nutritional) value of a protein is its amino acid profile balance. In 1966, the World Health Organization recommended using the Amino Acid Composition of chicken egg protein or human breast milk as a reference standard. The Nutritional Value of many animal Proteins is close to this standard, whereas plant proteins fall significantly short. Cereal proteins, for instance, are characterized by a low Lysine content. In contrast, the lysine content in proteins from various yeast strains ranges from 3% to 10%. Supplementing animal diets with feed yeast (alongside grain) compensates for the nutritional inadequacy of cereal protein, bringing it closer to the reference standard. Furthermore, yeast biomass is rich in Vitamins, particularly B-complex vitamins. The biomass of feed yeast (such as Candida utilis) used in agriculture is referred to as PVC (protein-vitamin concentrates).

The industrial production of feed yeast was established worldwide following World War I. In the 1930s, hydrolysates derived from agricultural and wood-Processing wastes began to be utilized as substrates for yeast cultivation. By the 1960s, Hydrocarbons (petroleum paraffins, diesel fuel) became popular substrates, followed shortly by alcohols (ethanol, methanol). In the former USSR, large-scale production facilities were established for "eprin"—ethanol-based yeast (Blagoveshchensk, Bashkortostan), "paprin"—paraffin-based yeast (Kremenchuk in Poltava Oblast, Novopolotsk in Belarus), and others.