Preliminary Study on Screening Fungalα-amylase-producing Strain and Its Solid-state Fermentation Conditions

An α-amylase-producing strain A019 was screened and isolated from distillers yeast and grain. Strain A019 was preliminarily identified as Aspergillus oryzae by morphologic taxonomy. Solid-state fermentation conditions for the production ofα-amylase including culture medium constituents, incubating time, initial pH, and temperature were studied. Response surface analysis(RSA) was used to optimize composition of culture medium. Solid state fermentation of Aspergillus oryzae A019 for the production ofα-amylase is carried out in a system consisting of wheat bran 8.0 g, soybean meal 2.28 g, yeast extract 0.1 g, K2HPO4·3H2O 1%, MgSO·47H2O 0.094%, water 12.9 ml, initial pH 5.0 and fermentation temperature 28 ℃. The fermentation cycle is about 48 h. With these optimal conditions, theα-amylase yield by A019 is about 410 U/g dry substrate.