Abstract:

In this study, the autolysis conditions for mannan preparation from waste beer yeast were optimized, and the autolysis method was compared with the common acid method and alkali method. Finally, the optimized autolysis conditions were magnified in 5-L fermentor. The results showed that the mannan content in yeast cell residue reaches maximum after 24h autolysis. The optimal autolysis conditions of yeast cell are as follows: temperature 50 ℃, NaCl concentration 2% and pH 6, and the effect order of the three factors is temperature＞NaCl concentration＞pH value. Under the optimal conditions the mannan content in yeast cell residue is up to 164.95 mg/g. This method is superior to acid method and alkali method. In scale-up experiment, the mannan content in yeast cell residue is 149.00 mg/g.

Key words: waste beer yeast, autolysis, mannan preparation