碱性条件高效降解小麦秸秆菌群的筛选及酶活力特点

Screening and Enzymic Activity Characteristics of Compound Microbes for Efficient Degradation of Wheat Straw under Alkaline conditions

【目的】借助微生物复合菌群来提高秸秆还田后的综合利用效率,是改善和维持农耕土壤状况及提高农作物产量的一种绿色有效的途径。筛选偏碱性土壤中高效降解小麦秸秆菌群,为偏碱性土壤小麦秸秆还田的有效利用提供试验数据和理论指导。【方法】选取在偏碱性条件下生长旺盛的代表性菌群,比较pH 9.0条件下羧甲基纤维素酶(CMCase)、滤纸酶(FPA)、木聚糖酶(Xylanase)和漆酶(Laccase)四种酶活力在不同复合菌群间的差异,并研究其培养液pH及培养时间对代表性复合菌群以上四种酶活力的影响。【结果】8组复合菌群中,黄孢原毛平革菌(Phanerochaete chrysosporium)+扩展青霉(Penicillium expansum)复合菌群培养96 h时,所观测的4种酶的活力均维持在最高水平;培养基初始pH仅显著影响该组复合菌群羧甲基纤维素酶活力(P<0.05),其活力在pH 9.0显著降低;培养时间对该组复合菌群木聚糖酶和漆酶活力无显著影响(P>0.05),而对羧甲基纤维素酶和和滤纸酶具有显著影响(P<0.05),即这两种酶在培养96 h时活力最高。【结论】在pH 9.0条件下,黄孢原毛平革菌+扩展青霉复合菌群的羧甲基纤维素酶、滤纸酶、木聚糖酶和漆酶活力均表现为最高,是较好的高效降解小麦秸秆的复合菌群。

[Objective]Using compound microbes to improve the comprehensive utilization efficiency of straw returning to the field is a green and effective way to improve and maintain agricultural soil conditions and increase crop yield.Screening microbes for efficient degradation of wheat straw under alkaline soil,these findings would provide experimental data and theoretical guidance for the effective utilization of wheat straw in alkaline soil.[Method]Representative microbes which grow vigorously under alkaline conditions were selected and used to explore how different compound microbes affect the activities of carboxymethyl cellulase(CMCase),filter paper enzyme(FPA),xylanase and laccase.Furthermore,the effect of pH value and the effect of culture time on the activities of these enzymes were analyzed for the representative compound microbes.[Result]Among the eight types of compound microbes,Phanerochaete chrysosporium+Penicillium expansum(Pc+Pe)compound microbes showed the highest the activities of the four enzymes.For the type of compound microbes mentioned above,the initial pH of the medium only significantly(P<0.05)affected the activity of CMCase,with the significant lower value under the condition of pH 9.0;and the culture time had no significant effects on the activities of xylanase and laccase,while had significant effects on CMCase and FPA,with the highest activities after 96 hours of incubation.[Conclusion]Under pH 9.0 condition,the compound microbes of Pc+Pe whose CMCase,FPA,xylanase and laccase activities are the highest,are preferable microbes for wheat straw degradation.