Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
Shenzhen Engineering Research Laboratory for Sludge and Food Waste Treatment and Resource Recovery, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
J Hazard Mater. 2021 Mar 15;406:124595. doi: 10.1016/j.jhazmat.2020.124595. Epub 2020 Dec 4.
Waste activated sludge (WAS) from wastewater treatment plants is an important reservoir of antibiotic resistance genes (ARGs). The fate of ARGs in this process was not revealed previously. The present study applied metagenomic approach to examine the occurrence and fate of ARGs in thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM), by comparison with mesophilic alkaline fermentation followed by mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The removal efficiency of two-stage anaerobic digestion (AD) to total ARGs is higher than that of one-stage AD. The hydrogen and methane production stages of two-stage AD processes have dissimilar impact on the fate of ARGs. Macrolide, lincosamide, and streptogramin (MLS) resistance genes were enriched, especially in the hydrogen production reactors of TM and MM processes. Statistical analysis of metagenomic profiles analysis suggested that bacA may be the differential ARG subtype of two-stage AD process. ARG-like sequences encoding antibiotic efflux pump, antibiotic inactivation and antibiotic target alteration mechanisms were identified as the dominant ARGs resistance mechanisms in all samples. Procrustes analysis showed that microbial community composition structured the resistome. Co-occurrence patterns between ARGs and microbial phylogeny revealed that 26 bacterial species might be potential hosts of 94 ARG subtypes.
污水处理厂的剩余活性污泥（WAS）是抗生素耐药基因（ARGs）的重要储存库。此前，该过程中 ARGs 的命运尚未揭示。本研究应用宏基因组学方法，通过与中温碱性发酵随后进行中温厌氧消化（MM）和单级中温厌氧消化（M）过程相比，研究了高温碱性发酵随后进行中温厌氧消化（TM）过程中 ARGs 的发生和命运。与单级 AD 相比，两级厌氧消化（AD）对总 ARGs 的去除效率更高。两级 AD 工艺的产氢和产甲烷阶段对 ARGs 的命运有不同的影响。在 TM 和 MM 工艺的产氢反应器中，大环内酯、林可酰胺和链阳性菌素（MLS）耐药基因得到了富集，特别是在 TM 和 MM 工艺的产氢反应器中。宏基因组分析表明，bacA 可能是两级 AD 工艺的差异 ARG 亚型。在所有样品中，编码抗生素外排泵、抗生素失活和抗生素靶位改变机制的 ARG 样序列被确定为主要的 ARG 耐药机制。普罗克斯特斯分析表明，微生物群落组成构成了抗性组。ARGs 与微生物系统发育之间的共现模式表明，26 种细菌可能是 94 种 ARG 亚型的潜在宿主。
