THE EFFECTS OF A CONTROLLED pH ENVIRONMENT ONPOLYSACCHARIDE SYNTHESIS BY AUREOBASIDIUM PULLULANS / 微生物学通报

ABSTRACT

The effect of pH on the extracellularpolysaccharide synthesis by Aureobasidium pullulans was studied by addding CaCO3and HCI. Cultivated in P2 liquid medium for 24h,pH dropped to 3. 6 because of strongly producing acid. Under this low pH environment, further fermentation for 120h,only 5. 9g/L of polysacharide was obtained. When grown in MP2 medium contaning0. 5 % CaCOs,the pH was kept above 5.0 during 144 hours,production of polysaccharide increased to 31g/L. The detailed information of effects of controlled pH on polysaccharide production showed an optimal pH value 5. 0 must be maintained through the fermentative period.