四环素对人粪便好氧堆肥过程及微生物群落演替的影响

以人粪便和锯末为实验材料,研究了四环素(TC)对好氧堆肥过程中理化性质、酶活性以及微生物群落演替的影响.实验共设4个处理:CK(不添加TC)、TC100(100 mg·kg~(-1)TC)、TC250(250 mg·kg~(-1)TC)和TC500(500 mg·kg~(-1)TC).采用高通量16S rRNA基因测序技术对堆肥中微生物群落结构进行分析.结果表明,TC对堆肥理化性质的影响与其浓度有关,堆肥中TC浓度的增加显著抑制了堆肥温度的升高,增加了水溶性碳(WSC)的残留,降低了种子发芽率(GI)并抑制了脱氢酶活性(DHA).堆肥温度、WSC、GI和DHA等堆肥参数都可以用来表征堆肥的腐熟度,以上结果表明堆肥中TC浓度高达500 mg·kg~(-1)时,TC阻碍了人粪便好氧堆肥过程并影响堆肥产物的腐熟.而且,TC浓度的增加显著改变了堆肥中的微生物群落演替,降低了微生物的多样性和丰度.TC对堆肥过程和堆肥产物腐熟的主要不利影响是对微生物群落结构的干扰和对生物活性的抑制.

Effects of Elevated Tetracycline Concentrations on Aerobic Composting of Human Feces: Composting Behavior and Microbial Community Succession

In order to investigate the effect of antibiotics on composting behavior, enzymatic activity, and microbial community succession during the aerobic composting of human feces using sawdust as the bulk carrier, tetracycline (TC) was added to the composting system at four different concentrations (0, 100, 250, and 500 mg·kg^-1). Microbial community succession was examined by high-throughput 16S rRNA gene sequencing. The results showed that the influence of TC on the physical and chemical properties of compost was related to its concentration. With the increase in TC concentration, the temperature increase during aerobic composting was inhibited, the water-soluble carbon (WSC) residue was increased, the germination index (GI) was decreased, and the dehydrogenase activity (DHA) was also hindered. Parameters, such as temperature, WSC, GI, and DHA, are widely accepted and representative indicators to evaluate compost maturity. Overall, when the concentration of TC was higher than 500 mg·kg^-1, the aerobic composting process and the maturity of the final compost were inhibited. Furthermore, elevated TC caused significant changes in microbial community succession and reductions in community diversity and abundance. Therefore, interference in microbial community structures and a hindrance to biological activity are believed to be the main adverse effects of TC on the composting process and maturity of the composting products.