Kvasny Prum. 1980; 26(3): 57-64 | DOI: 10.18832/kp1980010

Stimulating growth of Candida utilis with ammoniacal extract produced by reducing the concentration of nucleic acids.Peer-reviewed article

M. RUT, F. ŠTROS

When nucleic acids are being separated from yeast biomass produced through cultivation on synthetic ethanol, the by-products is ethanol-ammoniacal extracts, containing very active compounds having favourable effects upon the biosynthesis of yeast. Some of them stimulate growth, others are important sources of carbon and nitrogen in catabolic processes, or serve as structure elements taking part in anabolic processes producing important oligomers. From oxygen consumption in the period of yeast biosynthesis it has been calculated that the intensity of anabolic processes can be increased by 8.1 %. Stimulating effects of mentioned compounds brought another increase of yeast production amounting to 3.3%. Final, comprehensive evaluation of the whole cultivation stage and subsequent processing of yeast mass required to obtain yeast suitable for food industry gives the following figures: the yield of raw yeast mass increased from77 gto88.7 gof dry matter per100 gof synthetic ethanol. This yield represents - if expressed in terms of pure proteins - an increase from31,3 gto 37,7 gper100 gof synthetic ethanol. By using ethanol-ammoniacal extract the quality of final, processed product was improved and percentage of pure proteins increased from 57 % to 62.2 %. The share of nucleic acids was 1.4 %.When nucleic acids are being separated from yeast biomass produced through cultivation on synthetic ethanol, the by-products is ethanol-ammoniacal extracts, containing very active compounds having favourable effects upon the biosynthesis of yeast. Some of them stimulate growth, others are important sources of carbon and nitrogen in catabolic processes, or serve as structure elements taking part in anabolic processes producing important oligomers. From oxygen consumption in the period of yeast biosynthesis it has been calculated that the intensity of anabolic processes can be increased by 8.1 %. Stimulating effects of mentioned compounds brought another increase of yeast production amounting to 3.3%. Final, comprehensive evaluation of the whole cultivation stage and subsequent processing of yeast mass required to obtain yeast suitable for food industry gives the following figures: the yield of raw yeast mass increased from77 gto88.7 gof dry matter per100 gof synthetic ethanol. This yield represents - if expressed in terms of pure proteins - an increase from31,3 gto 37,7 gper100 gof synthetic ethanol. By using ethanol-ammoniacal extract the quality of final, processed product was improved and percentage of pure proteins increased from 57 % to 62.2 %. The share of nucleic acids was 1.4 %.

Keywords: Candida utilis, growth, ammoniacal extracts

Published: March 1, 1980