Effect of worts with different nitrogen compositions on fermentation performance of brewer's yeast

Six kinds of very high gravity worts ( 20 °P) with different nitrogen compositions were used to examine their effects on the biomass accumulation, degree of fermentation, ethanol yield and FAN consumption of brewer's yeast ( FBY0095) in this study.Results showed that fermentation performance of yeast was strongly affected by both of the level and the composition of nitrogen during very high gravity fermentation ( 20 ° P) . With the increases of sugars consumption rates, biomass, ethanol yield and the decrease of fermentation time by 20% were observed with the increase of the amounts of nitrogenous compounds in wort. When the nitrogen source was insufficient ( about FAN = 124.59 mg/L) , wort supplemented with appropriate soy protein isolate hydrolysates ( SPIH) induced the increases of biomass and ethanol yield by 5.03% and 4.43%, respectively, and the diversity of nitrogen sourch was increased which indicated that SPIH was an effective nitrogen source for yeast growth with a more complex nitrogen composition.