ВЛИЯНИЕ ВНЕШНИХ ФАКТОРОВ НА СВОЙСТВА ДРОЖЖЕЙ CANDIDA TROPICALIS ПРИ УТИЛИЗАЦИИ СПИРТОВОЙ БАРДЫ

Abstract

To prevent environmental pollution from distillery waste, enterprises are required to carry out complete processing of stillage and / or dispose of it at treatment facilities, but it is not possible to fully utilize distillery stillage due to the lack of necessary strains of microorganisms. Therefore, in the processing of distillery stillage, the choice of a strain of microorganisms with sufficient biological activity is of particular relevance. For the first time, biotechnological utilization by the Candida tropicalis yeast strain AP-31-KBP Y-4883 was used for the processing of distillery stillage. Yeast activity was increased by two external factors: physical (UV radiation) and chemical (19-mycosaminyl nystatinolide) exposure. A rational concentration of 19-mycosaminyl-nystatinolide (500 U) was established at which Candida tropicalis colonies reached their maximum size. The efficiency of vinasse disposal was assessed by the accumulation of amine nitrogen in an aqueous solution after vinasse hydrolysis, the amount of which was determined by the formal titration method. Yeast inoculum, obtained after exposure to external factors, was introduced into a nutrient medium based on vinasse, and aerobic treatment was carried out for 72 hours. The morphological properties of cells and their number were controlled by optical and atomic force microscopy, the results of which are consistent with each other and with the biological activity of yeast. The greatest changes in the morphology of the cell surface are noted after chemical exposure: compared with the initial sample, the average cell height increased by 0.24 µm, and the surface area increased by 1.25 times. An increase in the degree of utilization of alcohol stillage by yeast was shown in the series “Candida tropicalis strain AP-31-KBP Y-4883 without treatment → UV-treated strain → antibiotic-treated strain”: indicators of biological activity increased by 4.3% (the proportion of cells saturated with glycogen ) and by 6.67% (amine nitrogen content); biomass yield increased by 1.7%. Increments of indicators are calculated in the transition from the original sample to the treated antibiotic. The assessment of the environmental hazard of bard samples was carried out using biotesting. It is shown that the efficiency of vinasse utilization increases after its treatment with yeast, which was previously exposed to UV radiation and an antibiotic. These samples were characterized by the highest germination of seeds relative to bards not treated with yeast.