Utilization of potato chips industry by products for production of thermostable bacterial alpha-amylase using solid state fermentation system II. effect of moistening agent, supplementary substrates nitrogen source and application of the solid fermented substrate for some starches digestion

ABSTRACT

The effect of moistening agent and nitrogen source as well as the supplementary substrates on the formation level of thermostable alpha- amylase [EC3.2.1.1] by Bacillus subtilis VF50 on potato chips industry by-products using solid state fermentation technique [SSF] was investigated. The results revealed that whey permeate and cheese whey were excellent moistening agents; on the opposite, saline solution and distilled water were the lowest inducer moistening agents for enzyme formation among various inorganic nitrogen sources used. Wheat bran, defatted soybean meal and fodder yeast were employed as supplementary solid substrates by 50% [w/w] with the three tested wastes. The defatted soybean meal enchanted the formation of enzyme by about 10%-25%. The solid fermented substrate was applied to hydrolyze different concentrations of soluble potato, raw potato, maize and wheat starches. The crude enzyme in its solid state was more effective in hydrolyzing most of these substrates