Optimization of culture conditions for hyper-production of laccase from an indigenous litter dwelling fungus Mucor circinelloides GL1

Abstract

Fungal laccase is a robust enzyme with broad specificity and applicability in industrial processes. The successful use of enzymes requires large scale production within a short time. As laccase production is highly dependent on medium components and cultural conditions, the optimization of the same is essential for enhancement of its production efficiency. The objectives of present study were to screen litter dwelling fungi for their laccase production and optimize the culture conditions for hyper-production of laccase. A total of 58 fungal isolates were procured from 25 litter samples of plant origin collected from the Western Ghats of Karnataka, India. Among these, five including Mucor circinelloides GL1, Fusarium oxysporum GL2, F. oxysporum GL3, F. verticillioides GL5 and Ceriporiopsis sp. PA1 were selected for optimization studies based on their laccase producing ability. Maximum production was noticed in the optimized culture media and conditions compared to minimal media. Enhanced laccase production was observed by incubating them in optimized media at 28 °C for 8 days at 150 rpm. The laccase enzyme was purified from M. circinelloides GL1 using series of purification steps. The purified enzyme was a monomeric protein band with an apparent molecular weight of about 40 kDa. The present study reported that an indigenous litter dwelling fungus M. circinelloides GL1 found to be efficacious laccase producer in comparison to other isolates tested in this study. Therefore, it can further be utilized as a better biocatalyst in pertinent biotechnological applications.