Media optimization for ligninase production from rice straw by solid state fermentation using phanarochate chrysosporium

Abstract

A laboratory-scale study was carried out to produce lignin peroxidase (ligninase) by white rot fungus, Phanerochaete chrysosporium ATCC 24725 using rice straw as the major substrate. The optimization media was done using Central Composite Design (CCD) under Response Surface Model (RSM) from Design Expert ™ software, which involved glucose, peptone concentration and inoculum size as the parameters. Nineteen experimental runs were carried out for five days of incubation under condition of 32 oC and 70 % of moisture content. Then, second-order of quadratic model was developed using the regression analysis of the experimental results with the linear, quadratic, and interaction effects of the parameters. Analysis of variance (ANOVA) showed a high coefficient of determination R2 value of 0.9967 thus indicating a satisfactory fit of the quadratic model with the experimental data. Using statistical analysis, the optimum media compositions were determined to be 1.0 % (w/v) glucose, 0.3% (w/v) peptone and 10 % (w/v) inoculum size with a maximum activity of 956.96 U/ml ligninase. The validation experiment showed the maximum activity of lignin peroxidase was 968.2 U/ml after 5 days of fermentation which is 1.27 % higher than the predicted value.