Amylase and acid protease production by solid state fermentation using Aspergillus niger from mangrove swamp

Production of amylase and acid protease by solid state fermentation employing Aspergillus niger strain S(1)4, a mangrove isolate was evaluated. Wheat bran containing 60% moisture was used for fermentation with two inoculum sizes of 2x10(6) and 40x10(6) spores 10 g substrate(-1). The maximum amylase activity of 48.13 Ugdfs(-1) was recorded after an incubation period of 4 days at temperature 30 degrees C and pH 4.8 for the inoculum size 40x10(6) spores 10 g substrate(-1). The concentration of reducing sugar showed a significant negative correlation (-0.496, p<0.05) with amylase production. The peak acid protease activity was observed on day 6 (54.89 Ugdfs(-1)) for 2x10(6) spores 10g substrate(-1) and on day 4 for 40x10(6) spores 10g substrate(-1) under standard assay conditions of 30 degrees C and pH 2.7. The concentration of protein in the substrate was significantly (R=0.778, p<0.05) correlated with the acid protease production.