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为探索秸秆纤维素分解菌群筛选过程中,温度及碱处理小麦秸秆对菌群纤维素分解活性及菌群结构的影响,利用高温秸秆堆肥为筛选菌源,以碱处理小麦秸秆和未经碱处理小麦秸秆为碳源,分别在50和60℃条件下进行限制性筛选,最终获得18组具有纤维素分解活性的菌群。选择其中4组代表性菌群进行连续继代培养,监测相关性质,并利用PCR-DGGE技术结合主成分分析(PCA)方法对菌群结构进行分析。结果表明,从高温堆肥环境筛选秸秆纤维素分解菌群,培养温度及秸秆碳源均影响菌群的筛选效果。以碱处理小麦秸秆为碳源的菌群在分解秸秆过程中能够保持较好的菌群结构稳定性;60℃的温度条件和碱处理小麦秸秆的碳源条件更有利于获得高活性的纤维素分解菌群,并在此条件下成功筛选到菌群WDC2。该菌群分解碱处理小麦秸秆的纤维素内切酶活性(CMCase)达到1.01U/mL,分解率最高为60.8%。
In order to explore the effect of temperature and alkali-treatment of wheat straw on cellulolytic activity and flora structure of cellulolytic microbes in the process of screening cellulose straws, high-temperature straw compost was used as screening bacteria source, alkali-treated wheat straw and non- Wheat straw was treated as a carbon source and subjected to restriction screening at 50 and 60 ° C, respectively. Finally, 18 groups of cellulolytic cellulases were obtained. Four representative groups of bacteria were selected for continuous subculture and the related properties were monitored. The structure of the bacteria was analyzed by PCR-DGGE combined with principal component analysis (PCA). The results showed that screening the cellulosic cellulolytic flora from high temperature composting environment, culture temperature and straw carbon source all affected the screening effect of the flora. Alkaline treatment of wheat straw as carbon source in the process of decomposition of the straw can maintain a good flora stability; 60 ℃ temperature conditions and alkaline treatment of wheat straw carbon source conditions are more conducive to obtain high activity of cellulose Decomposing bacteria group, and in this condition successfully screened to flora WDC2. The bacterial cellulolytic alkali treatment of wheat straw cellulase activity (CMCase) reached 1.01U / mL, the highest decomposition rate of 60.8%.