玉米芯生物炭对污泥蚯蚓粪中微生物种群及ARGs的影响

较多的抗生素抗性基因(ARGs)积蓄于剩余污泥中降低了污泥蚯蚓粪的农用价值.为削减污泥蚯蚓粪中的ARGs,向污泥中分别添加1.25％和5％(质量比)的玉米芯生物炭(简称玉米芯炭),以无添加为对照组,揭示玉米芯炭对污泥蚯蚓堆肥过程中微生物种群结构及ARGs的影响.结果表明:添加高含量玉米芯炭显著促进污泥有机质的矿化,提升...

Effects of corncob biochar on the microbial communities and ARGs during vermicomposting of dewatered sludge

The higher content of antibiotics resistance genes (ARGs) accumulated in excess sludge lowers its agricultural value of vermicompost. To eliminate the content of ARGs in sludge vermicompost, this study aimed to reveal the effects of corncob biochars added in sludge on microbial communities and ARGs of vermicomposting. For this, 1.25% and 5% of corncob biochars, were separately added to dewatered sludge, comparing with the counterpart without addition of biochars. The addition high content of corncob biochars significantly (P < 0.05) promoted the mineralization of organic matter, thus increasing the conductivity and pH of sludge vermicompost. In addition, the corncob biochars (P < 0.05) enhanced the gene abundances of bacterial 16S rDNA and eukaryotic 18S rDNA in the vermicompost, resulting in a significantly (P < 0.05) positive correlation between the microbial abundance and biochar concentration. Compared to control, the relative abundance of Proteobacteria, Bacteroidetes, Actinomycetes, and Planctomycetes in sludge vermicompost with high content of corncob biochar decreased by 11.8%, 7.1%, 33.3% and 20%, respectively. However, its abundance of Firmicutes significantly increased by 40% (P < 0.05). Besides, the absolute abundance of macrolide resistance genes (ermF) and tetracycline resistance genes (tetX) in vermicompost with corncob biochars significantly decreased by 32%~45% and 13%~31% (P < 0.05), respectively. But, the abundance of class 1integron (intI1) and sulfonamides resistance genes (sul2) significantly increased by 47%~135% and 9%~42% (P < 0.05) in the final vermciompost, respectively. The addition of corncob biochar in sludge can promote the mineralizaiton of sludge by enhancing microbial number and diversity of microbial, but this addition only selectively reduce the ARGs in vermicompost.