THE EFFECTS OF A CONTROLLED pH ENVIRONMENT ON POLYSACCHARIDE 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 CaCO 3and HCl.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% CaCO 3,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.