Optimization of parameters for α-amylase production under solid state fermentation by Trichothecium roseum

The production of extracellular α-amylase by Trichothecium roseum was studied in solid state fermentation (SSF). The effects of wheat bran (WB), rye straw (RS), corncob leaf (CL), sunflower oil meal (SOM) and rice husk (RH) were examined. WB exhibited the highest enzyme production. The appropriate moisture level, incubation period, moistening agent, incubation temperature, inoculum level and particle size were determined. Effect of supplementary carbon, nitrogen sources and metal ions were examined. Optimal conditions for the production of α-amylase by T. roseum on WB as substrate in 0.1 M phosphate buffer at pH 7.0 were determined as initial moisture content of 85 % (w/v), incubation period of 8 days, incubation temperature of 30 C, particle size of 1,000 μm, lactose and urea (1 % w/w) as supplements. Addition of different metal ions (0.1M) to WB resulted in better αamylase production with CaCl2, addition of CuSO4 to WB resulted in decreased enzyme activities. Under the optimized culture conditions, the maximum enzyme production was 1,048 U/g of WB. One and a half increase in α-amylase productions were achieved in optimal fermentation conditions as compared with the medium containing WB alone as the substrate.