Alpha-amylase and glucoamylase production by Schwanniomyces castellii

A chromogenic substrate (Cibachron blue-amylose), and soluble starch and maltose were used to characterize the amylolytic system from Schwanniomyces castellii 3754. The strain was able to produce inducible alpha-amylase (EC 3.2.1.1) and glucoamylase (EC 3.2.1.3) when grown on different C sources. The effect of the C source was slightly different for alpha-amylase and glucoamylase production. Melezitose, maltose and soluble starch enhanced both alpha-amylase and glucoamylase synthesis to nearly the same extent; amylose, trehalose and cellobiose particularly induced alpha-amylase synthesis. The optimal pH for the release of both amylases was 5.5-7.0; maximal alpha-amylase synthesis, on the other hand, was observed in the medium buffered at pH 6.0. The optimal pH for alpha-amylase and glucoamylase activity was in the range of 4.5-7.2 and 4.2-5.5, respectively. Temperatures allowing maximal activity were 45 degrees C for alpha-amylase and 45-52 degrees C for glucoamylase; a rapid decline of both activities was observed just above these temperatures.