低温木质纤维素分解复合菌系PLC-8对玉米秸秆的分解特性

Decomposition Characteristics of Corn Stover by Microbial Consortium PLC-8 with Lignocellulose-degradation at Low Temperature

为提高东北寒区玉米秸秆的分解效率,突破低温的瓶颈,探讨了低温木质纤维素分解复合菌系PLC-8对玉米秸秆的分解效果及其微生物多样性。通过pH、玉米秸秆的减重、木质纤维素的含量、酶活性、有机酸含量等指标评价玉米秸秆的分解效果,采用变性凝胶电泳(DGGE)和高通量测序技术研究其微生物多样性。结果表明:pH先下降后回升至接近初始值;30 d后,玉米秸秆减重率达到43.65%;半纤维素、纤维素、木质素含量分别减少了61.13%、40.91%、14.25%;纤维素酶活性先升高后降低,其中滤纸酶和β-葡萄糖苷酶活性在第20 d,分别为0.054、0.025 U·mL^-1;内切酶和外切酶活性的最高值在第15 d,分别为0.032、0.030 U·mL^-1;木聚糖酶活性随着玉米秸秆的分解而逐渐升高,甲酸和乙酸分别在第20和15 d达到最高值。微生物群落分析表明,PLC-8由细菌和真菌组成,具有分解稳定性,在属的水平上细菌优势菌株为金黄杆菌属(Chryseobacterium)、短波单胞菌属(Brevundimonas)、不动杆菌属(Acinetobacter)等,真菌的优势菌株为肉座菌(Hypocreales)。

In order to improve the decomposition efficiency of corn stover in cold northeast region and break through the bottleneck of low temperature,this study explored decomposition effect and microbial diversity of microbial consortium PLC-8 of degradating corn stover at low temperature,evaluated the decomposition effect of corn stover through indicators such as pH,weight loss of corn stover,lignocellulose content,enzyme activity,and organic acid content.Denaturing gel electrophoresis(DGGE)and high-throughput sequencing were used to research its microbial diversity.The results indicated that the pH droped and then rose to the initial value;after 30 d,the weight-loss ratio of corn straw reached 43.65%;the content of hemicellulose,cellulose and lignin decreased by 61.13%,40.91%and 14.25%,respectively.Cellulase activity increased and then decreased,the filter paper enzyme andβ-glucosidase activities were at 20 d,which were 0.054 and 0.025 U·mL^-1,respectively.The highest endonuclease and exonuclease activities were at 15 d,which were 0.032 and 0.030 U·mL^-1,respectively.Xylanase activity gradually increased with the decomposition of corn stover.The highest values of formic acid and acetic acid were at 20 and 15 d,respectively.Microbial community analysis showed that PLC-8 was composed of bacteria and fungi and had decomposition stability.The dominant bacterial strains at the genus level were Chryseobacterium,Brevundimonas,Acinetobacter,and the dominant strain of fungi was Hypocreales.