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

Abstract

Production of amylase and acid protease by solid state fermentation employing Aspergillus niger strain S14, a mangrove isolate was evaluated. Wheat bran containing 60% moisture was used for fermentation with two inoculum sizes of 2x106 and 40x106 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 0C and pH 4.8 for the inoculum size 40x106 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 2x106 spores 10g substrate-1 and on day 4 for 40x106 spores 10g substrate-1 under standard assay conditions of 30 0C 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.