Abstract:
Lignocellulosic ethanol is one of the most promising renewable energy, but the high cost of enzyme is one of the major barriers. The enzyme cellulase from wild type Trichoderma reesei must be improved to make bioetanol more economical due to its low activity and concentration. To resolve this issue this research project aims to improve the cellulose activity by induce mutation on Trichoderma reesei TISTR 3081 via ethylmethanesulfonate (EMS), ultraviolet radiation (UV) and colchicine. After induced for double mutation with EMS treatment and ultraviolet radiation mutation, it was found that isolate E45-UV26 had higher specific activities of endoglucanase, exoglucanase, and β-glucosidase than those of wild type by 1.41, 1.69, and 2.53 times, respectively. Cellulase-producing ability was tested in Mandels' medium containing alpha-cellulose as the sole carbon source. Nucleotide base sequencing of cbh1 and cbh2 revealed that the base order of cbh1 had mutations in 4 positions, i.e. base orders 719 and 734 of the intron and base orders 812 and 924 of the exon. The base order of the exon caused a change in the synthesis of an amino acid, from Asparagine to Threonine. After treating isolates E45-UV24, E45-UV26, and E45-UV39 with colchicine for 20 days, it was found that isolate EV39-C69 had higher specific activities than those of wild type by milligram of protein of endoglucanase and exoglucanase by 2.16 and 1.35 times, respectively. However, as most isolates would have higher protein production after treatment with colchicine, if the activities were calculated as units per millilitre, EV24-C46 would be revealed that the activities of endoglucanase, exoglucanase, and β-glucosidase were 2.09, 2.20, and 1.21 times higher than those of the wild type, respectively. This study found that mutation with EMS together with ultraviolate radiation can increase the production of cellulase more effectively than using EMS alone in T. reesei TISTR 3081.