常温秸秆还田菌群的筛选及分解稻秆特性研究

【目的】对一组人工构建的常温(28℃)菌群的分解能力及分解性质进行研究,以获得常温下能够分解秸秆的微生物群及人工加速秸秆还田的分解技术。【方法】以多年堆积的稻草腐烂物为菌源,用改良的Mandels培养基经长期富集培养和定向驯化获得一组稳定的纤维素分解菌群。以标准的纤维素酶活性测定方法对分解过程中酶的活性进行评定,利用气质联机测定分解后的挥发性产物,用变性梯度凝胶电泳(DGGE)监测分解过程中菌种动态变化。【结果】5d后稻秆总减重量达到39.6%,在培养基占总体积1/5、pH=6、培养第5天时纤维素内切酶(CMC)活性表现最高,达到14IU·ml-1;培养过程中发酵液中有10余种挥发性产物,且不同时期产物的种类和浓度变化很大,从DGGE图谱发现在培养不同时期菌种组成有很大差异,通过各条带近缘种16s rDNA扩增信息构建系统树可见,各条带近缘种分别归属Clostridium、Brevibacillus、Bartonella、Bacteroidetes4个属。【结论】常温纤维素分解菌群能够加速稻秆分解。

Construction of a Normal Temperature Straw-Rotting Microbial Community and Its Character in Degradation of Rice Straw

Objective]In order to investigate the degradation activity,optimal condition of secreted cellulase activity and compose,the microbial community with efficient cellulose degrading ability in 28℃ was studied.Method]Microbial community canle from rotted rice sffaw was enriched and directional domesticated by improved Mandels medium.The standard cellulase activity assays were used to determine cellulase activity,the fermented juice was analyzed by gas chromatography mass spectrometry (GC/MS)method,and denaturing gradient gel electrophoresis(DGGE) was used to identify the composition dynamic of the community.Result]The results showed that the microbial community could degrade 39.6% of rice straw gross weight within five days.When the culture medium volume was 1/5 of the whole and pH at 6 on the 5 days culture,the CMC reached the highest of 14 IU·ml~(-1).During the dee straw degradation.more than ten kinds of products were detected using GCMS.DGGE detected the dynamic change of microbial community composition,and the microbial composition changed greatly in different periods.The phylogenetic tree derived from 16s rDNA sequence was found that the closest relatives belong to Clostridium sp.,Brevibacillus sp.,Bartonella sp.、Bacteroidetes sp.Conclusion]This microbial community could accelerate rice straw rotting.