Optimization of Solid-state Fermentation of Bacillus Subtilis

To study the effects of the initial p H, peptone concentration and different fermentation substrate on the growth of bacillus subtilis. For different fermentation substrate, liquid and solid state fermentation experiment was carried out. The result showed that the p H at the range of 6.5 to 7.0 made the bacteria grow fast, and p H 7.5 to8.0 was better to protease activity. The bran content of the solid medium was the main factor for the bacillus subtilis growth, while 20% soybean meal, 10% okara, 60% wheat bran and 30% corn flour were the best substrate for bacillus subtilis growth; soybean played an important role on the activity of protease, while 10% soybean meal, 10% okara, 50% wheat bran and 10% corn flour as a fermentation substrate, the activity of protease would be strongest.