Improvement of bilirubin oxidase productivity of Myrothecium verrucaria and studies on the enzyme overproduced by the mutant strain in the solid-state fermentation

The Journal of General and Applied Microbiology

Ashwani Sharma¹  Venkata Krishna Bayineni²  Sukrutha Suresh³ 

[1] Centre for Incubation, Innovation, Research and Consultancy (CIIRC), Jyothy Institute of Technology Campus;Centre for Incubation, Innovation, Research and Consultancy (CIIRC), Jyothy Institute of Technology Campus,Research Resource Centre, Visvesvaraya Technological University;Department of Biotechnology, R V College of Engineering

关键词: Bilirubin oxidase;    Myrothecium verrucaria;    solid-state fermentation;    specific activity;    thermostability;    UV irradiation;   

DOI  :  10.2323/jgam.2017.07.002

学科分类：微生物学和免疫学

来源: Applied Microbiology, Molecular and Cellulrar Biosciences Research Foundation

【 摘 要 】

Bilirubin oxidase has applications in the health and environmental sectors. Hence, several attempts have been made to increase enzyme yields. However, improvements were not very high. We report here the development of a mutant strain of Myrothecium verrucaria by using UV-rays, which produced 28.8 times more enzyme compared with the parent and was higher than the yields reported in earlier submerged cultures. The mutant strain produced 35.6 times more enzyme than the parent in solid-state fermentation, which is better than that previously reported for a solid-state fermentation process. The specific activity of the enzyme produced by the mutant was higher than that of the parental enzyme. Bilirubin oxidase from both strains showed an optimum activity at pH 7 and 40°C. However, the time required to inactivate half of the initial enzyme activity at 60°C was much higher in the case of the enzyme obtained from the mutant compared with the parental enzyme. The improved thermostability of the enzyme from the mutant strain could be due to the point mutations induced during the UV irradiation, since there was no change in the mass of the enzyme compared with the parental enzyme. The bilirubin oxidase of the mutant strain degraded the bilirubin faster than the enzyme obtained from the parent under similar conditions. Faster activity of the enzyme obtained from the mutant strain could be due to its lower Km (79.4 μM) compared with that of the parental enzyme (184 μM). Hence, the mutant enzyme showed a better functionality and thermostability, which will be beneficial for industrial applications.

【 授权许可】

Unknown