The Effects of Different Grain Brans Used as Substrates on Resistance to Catabolite Repression in Solid-State Fermentation Process

Abstract

Production of alpha-amylase from Penicillium brevicompactum was investigated in solid-state fermentation (SSF) using as substrate wheat bran (WB), rye bran (RB) and barley bran (BB) enriched with different amount of glucose or not. Consumption of glucose by fungal cells in WB and RB cultures was more effective than BB cultures. Optimal moisture levels for maximal alpha-amylase production in WB, RB and BB cultures without glucose were 55, 65 and 35 %, respectively. Water absorption capacities of substrates were WB>RB>BB. In SSF process, decrease in enzyme production was greater in high moisture level than optimal moisture level. According to the other two cultures, production of alpha-amylase from P. brevicompactum was strongly inhibited in higher moisture levels than optimal moisture levels in BB cultures enriched with 500 mg/g glucose.