Response Surface Based Optimization of Laccase Production from Cerena Unicolor with Wheat Straw as a Substrate

Laccase currently has a global market of more than 3 million USD, due to its redox potential, whose cost is determined by the raw material. Fungal laccase was produced from cheap agrowaste using a fungal source. Fungal isolation was done from microbes of decomposing cellulosic raw material. Cerrena unicolorwas found to be the most promising fungus and identified using ITS based sequencing, phylogenetic analysis and morphological study. Among different cellulosic materials, wheat straw was a better raw material for fungal isolates in laccase production. The optimization of laccase production was done using wheat straw with one factor at a time to find optimaltemperature (30 °C), incubation period (14 days), moisture percent (80) and pH (5). Response surface method with central composite design using yeast extract as an organic source of nitrogen or ammonium sulphate as an inorganic source was compared for laccase production. Copper sulphate was used as an inducer. It gave a significant model with quadratic equation which gave nearly similar experimental and predicted laccase production values. A 6-fold change in laccase production was found after optimization. The purification product after SDS PAGE showed the isolated laccase to have a single polypeptide of around 64 kDa. The study found that copper acted as an inducer in the laccase production, where solid state fermentation using wheat straw was a compelling combination for the isolated fungi in laccase production. The isolated fungi have the potential to produce laccase as a result of different growth parameters and the use of different agricultural wastes.