Production of alpha-amylase with Aspergillus oryzae on spent brewing grain by solid substrate fermentation.

Ten Aspergillus oryzae strains were screened in solid substrate fermentation for alpha-amylase production on spent brewing grain (SBG) and on corn fiber. SBG proved to be a better substrate for enzyme production than corn fiber. A Plackett-Burman experimental design was used to optimize the medium composition for the best strain. Solid substrate fermentation on optimized medium with A. oryzae NRRL 1808 (=ATCC 12892) strain in stationary 500-mL Erlenmeyer flask culture yielded 4519 U of alpha-amylase/g of dry matter substrate in 3 d. The whole solid substrate fermentation material (crude enzyme, in situ enzyme) may be considered a cheap biocatalytic material for animal feed rations and for bioalcohol production from starchy materials.