EFFECT OF TEMPERATURE ON PULLULAN PRODUCTION IN RELATION TO CARBON SOURCE

The effect of temperature on pullulan levels produced by Aureobasidium pullulans ATCC 42023 was studied in relation to the carbon source pre sent. Pullulan synthesis of fungal batch cultures, in which either suc rose or corn syrup was added as a carbon source, was followed for 5 da ys during which the incubation temperature was varied from 23 to 33-de grees-C. The optimal temperature for pullulan elaboration by A. pullul ans was 26-degrees-C independent of the carbon source added. The polys accharide concentration was lowest when the fungus was grown at 33-deg rees-C on either carbon source. Dry weights of the fungal cells were a lso determined during 5 days at various temperatures. The lowest cell dry weights were observed when the sucrose- or corn syrup-containing f ungal cultures were maintained at 26-degrees-C. Fungal cell weights we re usually highest at temperatures where pullulan production was relat ively low. The pullulan content of the polysaccharide produced by the fungus on sucrose was highest on day 4 when it reached 54%. The pullul an content of the polysaccharide was 100% after the fungus had been gr own on com syrup for 4 days. Thus, both temperature and carbon source strongly influenced the elaboration of actual pullulan by A. pullulans .