Institute for Nanoscience and Nanotechnology, Sharif University of Technology
Chemical and Petroleum Engineering, Sharif University of Technology
Chemical & Petroleum Eng, Sharif University of Technology
In this study, Glucoamylase production by Aspergillus Niger was investigated under solid state conditions with low cost by-products of agricultural processes as substrate. Highest enzyme production was observed when a combination of wheat bran (WB) and corn flour (CF) was used as compared to WB+ rice bran, WB+ rice flour and WB alone. Different additions of (CF) were tested and WB+ 10% CF showed to be the best combination. Study of the fermentations in flasks revealed 373.3 IU/gds and 41.4 g/l for the enzyme activity and protein concentration respectively under conditions of 301oC, pH4.7 and time 96 h. Optimum conditions provided by flask experiments were applied to produce the enzyme in a fermenter. A tray type sterilizable fermenter was designed (7-lit volume, 2 trays of 450x230x35 mm, and 2 l/min aeration). The fermentations were performed under aseptic conditions and resulted in enzyme activity and protein concentration of 400 IU/gds, 33.3 mg/gds respectively (under 302oC, pH=4.5 ~ 4.7, aeration 2 l/min, 90% relative humidity and time 72 h). The adequate amounts of enzyme activity, protein concentration and CO2 evolution revealed the efficiency of the bioreactor in comparison with flasks.