蚯蚓对城市污泥蚯蚓堆肥过程中微生物特征变化的影响

为揭示蚯蚓对城市污泥中微生物特征的影响和作用,本研究采用赤子爱胜蚓处理城市污泥,以无蚯蚓处理为对照,探讨蚯蚓对污泥堆肥中微生物数量、活性和种群变化的影响.结果显示:蚯蚓在前期能够显著提升脱氢酶的活性和细菌16S r DNA的丰度;从而加速有机物的降解,促进后期堆肥产物的腐殖质化.高通量测序结果表明:从60 d开始,蚯蚓组和对照组的细菌种群结构出现明显差异,蚯蚓处理能够显著增加最终产物的细菌种群的Chao1和Shannon指数.最终产物中,对照组的优势菌群为变形菌门(56%)、拟杆菌门(16.3%)和厚壁菌门(15.4%);蚯蚓组的优势种群有变形菌门(31.3%)、拟杆菌门(27.1%)、放线菌门(21.1%).与对照组相比,蚯蚓粪中放线菌和根瘤菌的丰度分别提高了13.1%和2.5%,表明蚯蚓的作用提升了堆肥产物作为微生物肥料的潜力.

Effects of earthworms on changes of microbial characteristics during vermicomposting of municipal sludge

The aim of this study was to reveal the effects of earthworms on microbial characteristics during vermicomposting of municipal sludge. For this purpose, the sludge stabilization experiments with and without addition of earthworms were carried out to investigate the changes of microbial density, activity and community, respectively. The results allowed that the earthworms could accelerate the decomposition of organic matter and promote the humification of final product, through arising dehydrogenase activity and microbial density in the beginning of the experimental period. Finally, a relative stable product was harvested in the treatment with earthworms rather than that of without earthworms. The high through put sequencing results revealed that earthworms could markedly enhance the bacterial indexes of Chao1 and Shannon during vermicomposting, compared to the counterpart without earthworms. The obvious difference of bacterial community structure between vermicomposting and its counterpart was found from the 60th days of the experiment. The phyla of the Proteobacteria (56%), Bacteroidetes (16.3%) and Firmicutes (15.4%) were predominant in the final products without earthworms. Comparatively, vermicomposting product predominated by the Proteobacteria (31.3%) followed Bacteroidetes (27.1%) and Antinobacteria (21.1%), respectively. Compared to the counterpart, the abundances of the Antinobacteria and Rhizobiales in the vermicompost were separately increased by 13.1% and 2.5%, suggesting that earthworms'' activity could elevate the potential of the vermicompost as microbial fertilizer.