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2019 (published: 11.06.2019)
Home > Issue > Utilization of sugars from wheat fermentatives with psychrophilic yeast under anaerobic conditions
Utilization of sugars from wheat fermentatives with psychrophilic yeast under anaerobic conditions
Kruchina-Bogdanov I.V. , Yakubov E.R., Kanarskii A. V. , Kanarskaya Z.A.
The possibility of reducing fermentation of sugars, the synthesis of ethanol and organic acids by strains of psychrophilic yeasts, such as Debaryomyces hansenii H4651, H433 and H18-3 and Guehomyces pullulans KB1-34, was studied under cultivation at the temperatures of 15; 20; 25°C in c. The effect of salt addition on the capabilities of the strains was also studied. Deep utilization of carbohydrates in fermentatives straw with a two-step method of cultivation was examied. The experiment was carried out in two stages: first, yeast strains were cultivated with and without adding ammonium sulfate, potassium salts, and phosphorus under aerobic conditions. Cultivation was carried out in 250 ml Erlenmeyer flasks for three days. After reaching the required biomass, mixing was stopped, thereby creating the anaerobic conditions necessary for the digestion and utilization of simple sugars. Fermentation lasted for three days also. The composition of the residual carbohydrates and fermentation products was analyzed by ion-exclusion HPLC using a Hitachi 2614 double-detection cation exchange resin (refractometer + photometer with a wavelength of 210 nm). The results show a prolonged activity of extracellular cellulolytic enzymes that hydrolyze the oligomeric carbohydrates of the straw fiber to form simple sugars as a substrate for digestionwith the production of secondary metabolic products. With limited air access heterofermentative acid formation occurs with a predominance of the propionic acid mechanism, as well as alcoholic fermentation.
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Keywords: cultivation of microorganisms; fermentative; psychrophilic yeast; fermentation; utilization of sugars.
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