Optimization of physical and nutritional factors for synthesis of lignin degrading enzymes by a novel strain of Trametes vericolor

Abstract

This paper reports the production of ligninase enzymes by a new strain of Trametes versicolor IBL-04 producing a novel pattern of ligninolytic enzymes with highest MnP activities followed by LiP and laccase. In previous studies Trametes versicolor has been reported to produce higher activities of MnP, followed by laccase and LiP. Lignocellulosic substrates including wheat straw, rice straw, banana stalks, corncobs, corn stover, and sugarcane bagasse were used in solid state fermentation (SSF) for the production of ligninases including peroxidase (LiP), manganese peroxidase (MnP), and laccase by Trametes versicolor IBL-04. Maximum production of MnP (998 U/mL), LiP (620 U/mL), and Laccase (49.7 U/mL) was observed after 5 days in the SSF medium containing 5g rice straw (60% w/w moisture) in still culture SSF. Moisture, pH, temperature, inoculums size, additional carbon and nitrogen sources, and surfactants had a significant influence on ligninase synthesis by the fungus. Production of ligninases was substantially enhanced by optimizing SSF production process. Maximum MnP (1775 U/mL), LiP (1663 U/mL), and laccase (99 U/mL) were produced when rice straw (5g) at 66.6 % moisture (w/w) receiving 5ml inoculum was incubated at pH 4.0 and 30oC in the presence of maltose (1% w/w) as carbon source, urea (0.2% w/w) as nitrogen source and 1mM Tween-80 (0.3 ml) as surfactant.