Effect of Culture and Environment on the Production of Heat Stable Glucoamylase by Mutated <i>Aspergillus </i>species UV-1 through Solid State Fermentation

Abstract

<i>Aspergillus </i>is a land isolate, which produces heat stable glucoamylase (1715 U/g fermented dry matter) in high quantity by solid state fermentation on wheat bran. The pure culture of this bacteria was mutated by ultra-violet radiation. Out of 5000 mutagens, 56 mutated colonies (showing difference in structure and enzyme producing capacity) were selected. These mutagens were grown in wheat bran based medium. After mixing the wheat bran and distilled water in 1:1 ratio and sterilization, bacteria were introduced into the flasks. Analysis was carried out after heating the flasks at 30^oC for 36 h. The mutant, whose highest production capacity was 4350 U/g fermented dry matter, was selected for further study and named <i>Aspergillus </i>species UV-1. The enzyme producing capacity of <i>Aspergillus </i>species UV -1 was affected by the presence as well as absence of wet agent, humidity level, heating temperature, carbon, nitrogen and minerals. In the flask, after heating the wheat bran and distilled water in the ratio of 1:1.5 , maximum enzyme production 6375 U/g fermented dry matter, was found. When this medium was completed with 1% glucose, 1% soyabean meal and 1 m mol magnesium sulphate and manganese sulphate the production of enzyme reached up to 7546 U/g fermented dry matter.