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添加外源菌剂已经被认定为一种能够加快牛粪堆肥中纤维素降解的一种有效方法。本研究在牛粪堆肥过程中添加外源菌剂,与同一条件下的对照堆肥做对比研究菌剂对堆肥中放线菌菌群的影响。结果表明,堆肥自第3天进入高温期,加菌剂堆肥可持续20 d高温(对照堆肥为14 d),其纤维素酶活性在堆肥过程中添加菌剂的要高于自然堆肥。利用PCR-梯度变性凝胶电泳(polymerase chain reactiondenaturing gradient gel electrophoresis,PCR-DGGE)方法并将检测结果测序来研究菌剂堆肥和对照堆肥中放线菌的菌群变化情况。根据16S r RNA基因序列构建的系统发育树,其显示了在不同阶段不同放线菌属在堆肥中起优势作用,共检测出10条不同时期的优势菌的条带。通过BLAST对比测序可知在堆肥过程中高温阶段作用的优势的条带分为3类:拟诺卡氏放线菌属(Nocardiopsis sp.)、链霉菌属(Streptomyces sp.)和节杆菌属(Arthrobacter sp.)。鉴定菌株中大部分堆肥高温期的放线菌菌株都与纤维素降解的菌株相关。研究结果表明,添加外源菌剂能够提高堆体温度并延长堆肥高温期,同时可以有效促进高温期放线菌的活性,致使放线菌群数量和多样性增加。本研究为开展堆肥放线菌群落功能多样性研究提供科学依据与技术指导。
The addition of exogenous agents has been identified as an effective way to accelerate the degradation of cellulose in cow dung composting. In this study, exogenous bacterial agents were added during the composting of cattle manures, and compared with the control compost under the same conditions to study the effects of the agents on the actinomycete flora in composting. The results showed that composting entered the high temperature period from the third day, and the compost composting could last for 20 days (control compost was 14 days). The cellulase activity of the composting agent was higher than that of natural composting. The changes of actinomycetes in the composting and control composts were studied by PCR-DGGE and PCR-DGGE. Phylogenetic trees based on the 16S rRNA gene sequence showed that different actinomycetes played a dominant role in compost at different stages and ten bands of dominant bacteria were detected at different stages. By BLAST comparative sequencing, we can see that the dominant bands in the composting process at high temperature are divided into three categories: Nocardiopsis sp., Streptomyces sp. And Arthrobacter sp.). Most strains of actinomycetes in the identified composites at high temperature were associated with cellulolytic strains. The results showed that the addition of exogenous agents can increase the temperature of the pile body and prolong the composting temperature, and can effectively promote the activity of actinomycetes at high temperature, resulting in an increase in the number and diversity of actinomycetes. This study provides a scientific basis and technical guidance for the study of functional diversity of actinomycetes community.