Studies on catabolite repression in solid state fermentation for biosynthesis of fungal amylases

Catabolite repression by glucose of the biosynthesis of alpha amylase and a myloglucosidase by Aspergillus niger CFTRI 1105 was studied in a solid stat e fermentation (SSF) and in submerged fermentation (SMF) systems and the re sults were compared. The addition of glucose did not enhance the production of alpha-amylase and amyloglucosidase in an earlier fermentation system. H owever, a drastic reduction in alpha-amylase production was observed in sub merged fermentation by the addition of 5.0 mg ml(-1) glucose and of amylogl ucosidase production by 10 mg ml(-1) glucose. Glucose concentrations above 50 mg ml(-1) completely suppressed the production of both enzymes in the in itial hours. In contrast, in the SSF system the repression was negligible, even when the glucose level was raised to 150 mg g(-1) wheat bran for both alpha and amyloglucosidase synthesis.