Strain improvement and process optimization of Trichderma reesei Rut C30 for enhanced cellulase production

Background: Cellulase activity and production cost are the main limiting factors for the conversion of lignocellulosic biomass into biofuels and bioproductions. In particular, the high cost of cellulase production in the utilization of lignocellulosic biomass led to a poorer competiveness than starch utilization for biofuels and bioproducts. High cost of cellulase production is still a key barrier. Increasing the cellulase activity and reducing its cost have been targets for numerous research and development efforts. Results: After two rounds of mutagenesis, the mutant 30s-3-13 was obtained from Trichoderma reesei Rut C30 and exhibited more than doubled filter paper activity and carboxymethyl cellulase activity and 0.45-fold cotton activity separately. The cellulase activity and productivity reached 15.6 FPU ml(-1) and 144 FPU l(-1)h(-1) in a 5 l fermentor using the optimized process parameters. The C/N ratio, temperature and pH control were the significant factors affecting the cellulase activity. Conclusion: The results showed that the mutant 30s-3-13 was capable of high cellulase production at lower cost. The combination of strain improvement and process optimization was a promising approach for the cost-effective production of cellulase in the future.