Optimization of fermentation conditions of high biomass Saccharomycesn cereviaeae DW-AQJM-38.

Optimal fermentation medium and fermentation conditions for Saccharomycesn cereviaeae DW-AQJM-38 were studied based on single-factor experiments and the orthogonal test. The best fermentation medium for Saccharomycesn cereviaeae DW-AQJM-38 contained 2.1% of brown sugar, 1.7%of soya peptone, 0.5%of yeast extract, 0.3%of potassium dihydrogen phosphate, 0.05%of magnesium sulfate, and 0.015%of calcium chloride anhydrous; with the initial pH value of 6.5-7.0. The best fermentation conditions were found as: temperature 30℃,liquid volume 30ml/500ml, inoculums size 5% or 10%, inoculums time 16-17h, and shaking speed 200rpm. For the sugar-feeding process, the best sugar-feeding time were 10h,13h and 16h, with the sugar dosage being of 2.5%. After 21-hour fermentation, biomass and number of Saccharomycesn cereviaeae reached 50.0g/L and 4.5×109cfu/ml, respectively.