Isolation and growth characteristics of the salt-tolerant yeast for soy sauce flavor improvement

Two strains of salt-tolerant yeast C5 and C6 for soy sauce flavor improvement were isolated from soy sauce moromi,and their salt-tolerance capability and growth characteristics were investigated.It was shown that the two yeast strains could grow in the suspension even with salinity of 24%(w/w).In soy sauce the optimum growth conditions for them were pH value(4.5~5.5),the cultivation temperature(28℃~32℃),alcohol content(0~1.2%,v/v) and glucose or fructose concentration(2%~4%,w/w).The yeast C5,however,showed more alcohol-tolerant,faster in reducing sugar consumption and higher ethanol productivity than C6.