微生物发酵床不同深度垫料的细菌群落多样性

为了解微生物发酵床不同深度垫料细菌的多样性,明确不同深度的细菌群落组成,采用五点采样法,收集了发酵床表层10 cm、中层30 cm、深层50 cm的垫料,分别进行垫料宏基因组DNA的提取,原核生物16S rDNA基因V3～V4区的扩增及Illumina高通量测序。试验共获得1 045 225条序列,共包含32门、303科、609属和1834类OTUs。表层垫料细菌数量最多,中层垫料细菌种类最多。微生物发酵床不同深度垫料的细菌群落有所差异,在表层垫料中,变形菌门(25.9%)和放线菌门(10.2%)相对含量高;中层垫料中拟杆菌门(27.8%)、变形菌门(25.1%)和厚壁菌门(17.0%)相对含量高。发酵床垫料表层和中层细菌多为有机物降解菌,主要为异常球菌——栖热菌门的特吕珀菌科、变形菌门的黄单胞菌科和拟杆菌门的黄杆菌科细菌。随着垫料深度增加,拟杆菌门(33.3%)和螺旋体门(9.2%)含量升高,厌氧菌如螺旋体门的螺旋体科、拟杆菌门的腐螺旋菌科在深层垫料中达到峰值。研究表明,表层垫料中微生物含量最高,代谢最为活跃,是主要的有机质降解层;深层垫料厌氧菌含量高。

Bacterial community diversity of litters at different depths in microbial fermentation bed

The main objective of this study is to investigate the bacterial communities of litters at different depths in a microbial fermentation bed(MFB), and reveal the relationship between bacterial diversity and depths of the litters. In the light of the above considerations, litters from three different depths(10 cm, 30 cm, and 50 cm)in five locations of the MFB system were collected, and their bacterial communities were evaluated using high-throughput sequencing. A total of 1 045 225 sequences were obtained, and the tested litters contained 32 phyla, 303 families, 609 genera, and 1834 operational taxonomic units(OTUs)of bacteria. The shallow litters had the highest content of bacteria while the middle litters had the greatest diversity. The microbial community was obviously related to the depth of the litters. The contents of the phyla Proteobacteria(25.9%)and Actinobacteria(10.2%)in the shallow litters were higher than they were in other litters. The middle litters had high contents of Bacteroidetes(27.8%), Proteobacteria(25.1%), and Firmicutes(17.0%). Importantly, our results showed that contents of the organic matter-decomposing bacteria, including Trueperaceae(Deinococcus-Thermus), Xanthomonadaceae (Proteobacteria), and Flavobacteriaceae(Bacteroidetes)consisted of numerous species and were in high abundance in the shallow litters. However, the contents of the phyla Bacteroidetes(33.3%)and Spirochaetes(9.2%)in the deep litters were higher than those in the shallow litters were. The deep litters had the highest content of anaerobic bacteria including Spirochaetaceae(Spirochaetes)and Saprospiraceae (Bacteroidetes). The bacterial community consisted of numerous species and the most active metabolism occurred in the shallow litters, while the contents of anaerobic bacteria increased with increasing litter depth.