Effect Factors on Cultivating Saccharomyces cerevisiae

Saccharomyces cerevisiae mainly grows in favor of acidity condition and needs more plentiful glucose.In the cultivating process,the yeast would die or even autolyse.The autolysis phenomenon can not be avoided in this process,we can only control the autolysis degree.This research focused on the important factors related to cultivating yeast,that are pH,capacity of liquid medium,concentration of yeast extract and glucose,wort,temperature and ultraviolet radiation.And then to make sure the optimal cultivating condition for Saccharomyces cerevisiae as following: the cultivating pH is 5,the optimal temperature is 30℃,the inoculate capacity is 100 mL/L,concentration of glucose is 50 g/L,concentration of yeast extract is 2.0 g/L,capacity of liquid medium less than 60% of cultivating flask in order to gain more dissolved oxygen.Furthermore,increasing the rotating speed of pulsator could also add dissolved oxygen,40 r/min is optimal.Filtering the condensation substance from wort was needed before cultivating Saccharomyces cerevisiae.In the cultivating process,infections with other bacteria and ultraviolet radiation should be avoided to reduce the probability of decrepitude,death and autolysis of Saccharomyces cerevisiae.