Biotechnical Production of Extracellular Enzymes by Bacillus Subtilis

摘要

The production of extracellular enzymes by Bacillus subtilis was studied. Many suitable strains for a-amylase, protease and Beta-glucanase production were isolated. The productivity of isolated strains was improved by using UV-irradiation and alkylating agents. Alpha-Amylase production was increased by over 100%. Many raw materials were tested as medium ingredients. The best results were obtained using combinations of different raw materials in high concentrations of about 10% w/v. The carbohydrate/nitrogen ratio was found to be an important factor in enzyme production by B. subtilis. Conditions for fermenter cultivation were examined for the production of enzymes. It was found that the control of aeration and pH was of great significance. Also the feeding of starch during cultivation seems to increase the production of Beta-glucanase considerably. With the developed mutants and using cheap raw materials in the media and methods presented in this study, it is possible to produce extracellular enzymes in high yields.