Improvements in solid-state fermentation for glucoamylase production

Solid-state fermentation of wheat bran by Aspergillus niger for glucoamylase production was studied. Whole dough containing spores, and wheat bran, was used as inoculum and a 5% (w/w) level was found optimum for enzyme production. Improved nutrients supplementation, addition of whole corn (yellow) flour and better process controls resulted in a 5–6-fold increase in enzyme yield over preliminary results from laboratory-flask experiments. The productivity was about 520–560 IU enzyme per gram dry substrate in 96 h. When scaled-up in tray fermenters, about 80% enzyme production was achieved in comparison to flask experiments, in 36 h.