Multiple non-polysaccharide-degrading enzyme production from solid state fermentation of Aspergillus niger AK10

Abstract

Aspergillus niger strain AK10 was isolated from ingredients used for animal feed production. It was found to be capable of producing multi-enzymesrequired for animal feed supplements, namely phytase, xylanase, cellulase and mannanase. Except for mannanase, solid state fermentation of AK10 for production of the other three enzymes was found to be best done on RB medium which was composed of rice bran mixed with mineral salt solution [0.1% K2HPO4, 0.02% MgSO4, 0.01% CaCl2 and 0.25% (NH4)2SO4] at a weight by volume ratio of 1:1. The solid medium for high mannanase production was SM medium containing soybean meal and mineral salt solution at 1:1 (w:v) ratio.The optimum temperature for growth of AK10 was at 35oC for 4 days. The mineral salts solution was found to be an important factor for mannanase activity. Each enzyme was characterized for the levels of optimum temperature and pH for the activity and stability. Efficiency of the crude multi-enzyme mixture in digesting grass was tested and found to help increase the metabolizable reducing sugar and protein by 3 and 13.5 folds,respectively. It also helped releasing the free absorbable phosphorus by 10 fold.