UV-EMS复合诱变强化生物预处理秸秆产乙醇

Enhanced biological pretreatment of straw for ethanol production by UV-EMS composite mutagenesis

玉米秸秆中木质纤维素结构复杂,采用安全、绿色的生物法对秸秆进行预处理,可以有效提高其能源转化效率进而实现秸秆的减量化及高效资源化利用。针对目前生物预处理法中存在的野生菌株产酶能力较弱、酶活性低的问题,在优化条件下对野生木质素降解菌株FM1进行紫外线照射(UV)与甲基磺酸乙酯(EMS)复合诱变,并将筛选获得的突变菌株UEM2应用于秸秆生物乙醇制备的预处理过程中,通过秸秆木质素降解率及乙醇产量等指标来对比探究诱变对秸秆预处理的影响。结果表明,UV-EMS复合诱变使菌株木质素降解酶活性得到有效提高,对秸秆的生物法预处理起到了一定的强化作用,且效果优于单一诱变;UEM2预处理后木质素降解率达到38.86%,比FM1处理组提高了63.55%;通过同步糖化发酵(SSF),测定UEM2组生物乙醇质量浓度达到12.17 mg·mL^(-1),是FM1组的1.36倍,进一步验证了诱变对预处理的强化效果。该研究结果可为秸秆生物法预处理的应用和发展提供理论参考。

The structure of lignocellulose in corn straw is complex.Using safe and green biological methods to pre-treat straw can effectively improve its energy conversion efficiency and achieve the reduction and efficient resource utilization of straw.In response to the problems of weak enzyme production ability and low enzyme activity of wild strains in current biological pretreatment methods,this study conducted a combination of ultraviolet radiation(UV)and ethyl methanesulfonate(EMS)mutagenesis on the wild lignin degrading strain FM1 under optimized conditions,and applied the selected mutant strain UEM2 to the pretreatment process of straw bioethanol preparation.The effects of mutagenesis on the pretreatment effect of straw were compared and explored through indicators such as straw lignin degradation rate and ethanol yield.The results showed that UVEMS composite mutagenesis effectively increased the activity of lignin degrading enzymes of the strain,and played a certain strengthening role in the biological pretreatment of straw,and the effect was better than single mutagenesis.After pretreatment with UEM2,the lignin degradation rate reached 38.86%,which was 63.55%higher than that of the FM1 treatment group.By simultaneous saccharification fermentation(SSF),the bioethanol yield in the UEM2 group was determined to reach 12.17 mg·mL^(-1),which was 1.36 times higher than that of the FM1 group,further verifying the strengthening effect of mutagenesis on pretreatment.The research results can provide theoretical reference for the application and development of straw biological pretreatment.