嗜热毁丝菌裂解性多糖单加氧酶TtLPMO9I的酶学性质及其功能研究OA北大核心CSTPCD

[Objective]To explore a novel lytic polysaccharide monooxygenase(LPMO)enzyme and to elucidate its crucial role in cellulose degradation.[Method]A new LPMO enzyme Tt LPMO9I was cloned from Thermothelomyces thermophilus genome,and its sequence and structure were systematically analyzed to determine its evolutionary characteristics.The enzymatic properties of TtLPMO9I were characterized using the DNS method;the impact of different concentrations of ascorbic acid on the activity of TtLPMO9I was investigated by adding external electron donors to the reaction system.By detecting the production of reducing sugars,the synergistic effect between TtLPMO9I and cellulase was calculated when pretreated corn straw and Avicel were used as substrates.[Result]TtLPMO9I presented the highest activity at 60℃and pH 5.0.After 12 h of incubation at 60℃,approximately 54%of its activity remained.TtLPMO9I still maintained initial enzyme activity at pH 6.0-8.0 for up to 12 h.Adding an external electron donor,ascorbic acid,to the reaction system,the activity of TtLPMO9I increased to 184%.In addition,TtLPMO9I has shown promising synergistic effects with cellulase in the degradation of pretreated corn straw and Avicel.Adding 50-200 μg of Tt LPMO9I into the degradation system increased reducing sugar yields by 34%-142%and 6%-46%respectively.[Conclusion]Tt LPMO9I not only has excellent thermal and pH stability,but also has outstanding performance in degrading lignocellulose,providing potential high-quality enzyme resources for industrial production.