耐低温降解玉米秸秆复合菌剂的构建及其降解效果评价

Construction of Complex Microbial Agent Resistant to Low Temperature Degradation of Corn Stalk and Evaluation of Its Degradation Effect

为解决严寒地区低温条件下农业废弃物自然处理效率下降的问题,从长白山典型静水水底污泥筛选优势低温降解纤维素菌并进行26S rRNA PCR测定菌种,明确其分类地位。通过全组合构建菌株多样性为1~5的复合菌系,分别检测复合菌系的秸秆相对降解率及其滤纸酶、纤维素内切酶和木聚糖酶活性,利用方差分析和相关性分析等方法研究菌株多样性和组成对复合菌系玉米秸秆降解效果及其纤维素酶活性的影响。结果表明,筛选得到5株可在15℃时纤维素水解能力强且可降解玉米秸秆的菌株。经26S rRNA序列鉴定和系统发育分析,5株降解菌分别为链霉菌(Streptomyces)、棘孢木霉(T.asperellum)、钩状木霉(T.asperellum)、曲霉(Aspergillus)和青霉(Penicillium),与NCBI数据库的序列相似度均超过99.95%。抽样效应分析发现,不同菌株对复合菌系的秸秆降解效果、滤纸酶和纤维素内切酶活性的影响不同。全组合复配结果表明,以编号为AX1、AX3和AM4的组合对玉米秸秆降解效果最佳、酶活性最高,复合菌系的秸秆降解能力和纤维素酶活力均高于单一菌株,且随着菌株多样性水平的增加而提高。试验表明该复合菌剂可以在15℃下有效降解纤维素类物质,提高玉米秸秆的降解效率效果。

In order to solve the problem of the decline in the efficiency of natural treatment of agricultural waste under low temperature conditions in severe cold areas,the dominant low-temperature degrading cellulose bacteria were screened from the typical still water bottom sludge of Changbai Mountain,and 26S rRNA PCR was performed to determine the bacterial species to clarify its classification status.The compound strain with a strain diversity of 1 to 5 was constructed through the entire combination,the relative degradation rate of the straw of the composite strain and its filter paper enzyme,endocellulose and xylanase activities were detected respectively,the effect of strain diversity and composition on the degradation effect of composite strains of corn stalk and its cellulase activity were studied by methods such as variance analysis and correlation analysis.The results showed that 5 strains that could hydrolyze cellulose at 15℃and could degrade corn stover were selected.After 26S rRNA sequence identification and phylogenetic analysis,the 5 strains of degrading bacteria were Streptomyces,T.asperellum,T.asperellum,Aspergillus and Penicillium,the sequence similarity with NCBI database was more than 99.95%.Sampling effect analysis showed that different strains had different effects on straw degradation,filter paper enzyme and cellulose endonuclease activities.The results of the full-combination combination showed that the combination numbered AX1,AX3 and AM4 had the best degradation effect on corn stalks and the highest enzyme activity.The straw degradation ability and cellulase activity of the composite strain were higher than that of a single strain,and it increased with the increase of strain diversity.The experiment showed that the composite microbial agent could effectively degrade lignocellulose at 15℃,and improve the degradation efficiency of corn stalks.