填埋场微生物功能特征与填埋时间关系研究

Research on the Functional Characteristics of Microbial Communities in Landfills in Relation to Landfill Time

微生物在生活垃圾填埋场稳定化过程中起到核心作用,但不同稳定阶段微生物群落演替规律及其代谢功能特征研究较少,直接影响了调控方法的科学选择。该研究以不同填埋时间垃圾为对象,采用16S rRNA高通量测序技术,对其微生物群落多样性和功能基因属代谢特征进行了探究。结果表明,填埋场中微生物群落组成与填埋时间有关,主坐标分析分别解释了微生物群落丰度变化的26.26%和12.04%,埋时间<10 a的垃圾细菌群落组成和其他样品呈现显著差异;微生物α-多样性随填埋龄的增加而降低;厚壁菌门Firmicutes(相对丰度32.1%~64.1%)、变形菌门Proteobacteria(相对丰度28.6%~53.3%)是填埋场的优势菌门,Firmicutes具有促进大分子有机物降解的作用,随填埋时间增加而比例上升;Proteobacteria作为分解可溶性底物菌门,由于易降解有机物随填埋时间增加逐渐减少,其相对丰度呈下降趋势;填埋场功能基因属呈现多样性,共发现4种硫酸盐还原属、2种氮循环属、6种产甲烷功能属、1种有机污染物降解属、6种纤维素分解属及13种塑料降解属;KEGG 1级中的新陈代谢途径是最丰富的代谢功能,氨基酸代谢、碳水化合物代谢、能量代谢及辅助因子和维生素代谢是KEGG 2级中相对丰度较高的代谢途径。RDA冗余分析表明,生物可降解度、有机质、pH、纤维素、木质素及含水率是驱动填埋场微生物多样性的重要环境因子。

Microbes play a central role in the stabilization process of domestic waste landfills.However,the succession of microbial communities and their metabolic functional characteristics at different stabilization stages remained rare,directly affecting the scientific choice of regulation methods.The research investigated the diversity of microbial communities and metabolic characteristics of functional gene genera using 16S rRNA high-throughput sequencing technology for refuses at different disposal ages.The results showed that the microbial community composition was related to the ages of the landfill,and principal coordinate analysis(PCoA)explained 26.26%and 12.04%of the changes in microbial community abundance,respectively,and the bacterial community composition of the refuses with a disposal ages<10 years showed a significant difference from the other samples.Microbial alpha diversity decreased with increasing disposal age.Firmicutes(32.1%~64.1%)and Proteobacteria(28.6%~53.3%)were the dominant phyla in the landfill,and the proportion of Firmicutes increased with the increase of disposal ages as it promoted the degradation of macromolecular organic matter.The relative abundance of Proteobacteria,as a phylum that decomposes soluble substrates,tended to decrease due to the gradual decrease of easily degradable organic matter with the increase of disposal ages.The functional gene genera in landfill were diverse,with 4 sulfate-reducing genera,3 genera involved in the nitrogen cycle,6 functional genera involved in methanogenic processes,1 organic pollutant-degrading bacterium,6 cellulolytic genera and 13 plastic-degrading microorganisms found.The metabo⁃lism pathway in KEGG Level 1 was the most abundant metabolic function.Amino acid metabolism,carbohydrate metabolism,energy metabolism and metabolism of cofactors and vitamins were the relatively abundant metabolic pathways in level 2.RDA redundancy analyses indicated that BDM,OM,pH,C,L,and moisture were important environmental factors driving microbial diversity in the landfill.