Over production of xylanase from Bacillus mojavensis by classical mutagenesis

Abstract

Introduction: Over production of xylanase, enzyme from microbial resources was always considered by researchers. The present study was conducted to evaluate the effects of inductive mutagenesis, classical type, on enhanced xylanase production from Bacillus mojavensis in order to access to potent mutants with high capacity of production. Materials and methods: Bacillus mojavenis PTCC20 1723, by proving its potentiality to produce xylanase, was used as a wild strain for over production of the enzyme by classical mutagenesis. After using mutagens such as UV and nitrous acid, screening of different mutants was accomplished. Initial screening was based on the enhanced H/C21 ratios of the colonies in comparison with that of the wild strain on xylan containing agar medium. Results: Among numerous screened colonies, seventy two mutants with H/C ratio bigger than the parental strain, (H/C≥1.6), were isolated. At the next step, enzyme production of mutants was compared with that of the parental strain in liquid cultures. Overall, among 67 screened mutants, 2 mutants, which produced 319.58 and 330.56 IU/mL xylanase, were selected. These mutants produced 3.3 & 3.45 times more enzyme than the native strain, with preliminary production level of 95.73 IU/mL. Discussion and conclusion: These mutants, as superior ones & resulted from the classical mutagenesis, were selected as the best strains.

Keywords

• Bacillus mojavensis
• Xylanase
• Random mutagenesis
• UV rays
• Nitrous acid