Cellulase production with mixed culture of Aspergillus niger and Bacillus sp.

Four combination methods of 4 strains were determined according to growth and enzyme production.Combination of mixed strains with D2-1 and S3-7 was determined as the best for cellulose degradation by activity of cellulose.Fermentation conditions of mixed strains were optimized,which were as follows: innoculum 8%,filling 125ml broth in 250ml erlenmeyer flask,carbon source straw and wheat bran with ratios of 2∶3,nitrogen source yeast extract and ammonium sulfate with ratios 1∶1,and ratios of carbon to nitrogen 7∶1,initial pH value 5.0,fermentation for 4 d under 28℃.Activity of FPA could achieve 535.08U/ml under the optimum conditions,which was 4.45 and 4.61 times as that of the initial Aspergillus miger D2-1 and Bacillus S3-7.