Improvement of Cellulase Production and its Characteristics by Inducing Mutation on Trichoderma reesei 2414 under Solid State Fermentation on Rice By-products

<p><a href="/public/journals/52/1-Hamidi.png" target="_self"><img src="/public/site/images/mmoslemi/1-Hamidi-Small.png" alt="" /></a></p><p> </p><p><strong>Background and Objective: </strong>Solid State Fermentation is an economic technology to produce value-added products. Also, the use of agricultural by-products, as a waste management strategy, has recently been considered. On the other hand, the new mutants are interesting for the production of enzymes. The aim of this study was to investigate the effect of mutation on the improvement of cellulase quality. Therefore, rice by-products were used under solid state fermentation for production of cellulase. Moreover, the characteristics of the new cellulose produced from the new mutated strain was studied.</p><p><strong>Material and Methods: </strong>Cellulase was produced under solid state fermentation process. Spore suspensions of <em>Trichoderma reesei </em>were subjected to Co⁶⁰ γ irradiation and mutated. The activities of cellulases (from parent and mutants) were compared. The effects of temperature and pH on cellulase activity and the stability of cellulase in optimum condition were investigated.</p><p><strong>Results and Conclusion: </strong>Cellulase was successfully produced under solid state fermentation on the mixture of rice by-products as substrate. The results showed that mutation had a significant effect on cellulase activity and Characteristics. <em>Trichoderma reesei </em>B (a mutated strain) had about 30% filter Paperase and 23% Carboxymethyl Cellulase higher than its parent. Cellulase activity of <em>Trichoderma reesei </em>B was 47% higher than its parent at the optimum temperature (50°C). In other temperatures, the activity of cellulase extracted from <em>Trichoderma reesei </em>B was significantly higher than that of the others; for example, at 60°C, the enzyme activity was 120% higher than its parent. It is notable that an 84% increase in the enzyme activity was observed at the optimum pH (4.5) after mutation and cellulase activity increased from 0.72 U g-1 dry solid to 1.31 U g-1 dry solid.</p><p><strong>Conflict of interest: </strong>The authors declare no conflict of interest.