School of Environment, State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090, China.
School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
Environ Sci Technol. 2022 Nov 1;56(21):15130-15140. doi: 10.1021/acs.est.2c00481. Epub 2022 Aug 19.
Anaerobic digestion (AD) has been widely employed for converting various biowastes into renewable energy. However, AD of gentamicin mycelial residues (GMRs, a byproduct of gentamicin production) is limited by ammonia inhibition and antimicrobial resistance risk. Compared to mesophilic AD (MMAD) of GMRs, this study looked into three semicontinuous AD processes, i.e., codigestion with wheat straw, thermophilic digestion (TAcoD), and AD at shortened retention time (RT). Results showed that a stable and safe AD could be achieved under suitable operating conditions. Co-digestion could effectively mitigate the adverse effect of ammonia inhibition. The methane production increased by 35.86% in TAcoD compared to that in MMAD and 43.99% of hazardous waste was reduced in TAcoD. Concerning the antimicrobial resistance of AD system, gentamicin was degraded efficiently and the degradation process was not involved in the expression of antibiotic resistance genes (ARGs) related to modifying enzyme. Effective removal of ARGs under three operating strategies was associated with a higher reduction in bacterial abundance of potential hosts. In addition, the changes in the relevant proteins for transformation and conjugation as predicted by PICRUSt suggested that thermophilic condition and shorter RT were conducive to the reduction of the dissemination risks of ARGs.
厌氧消化（AD）已广泛用于将各种生物废物转化为可再生能源。然而，由于氨抑制和抗药性风险，庆大霉素菌丝体残余物（GMRs，庆大霉素生产的副产物）的 AD 受到限制。与中温 AD（MMAD）相比，本研究考察了三种半连续 AD 工艺，即与小麦秸秆共消化、高温消化（TAcoD）和缩短停留时间（RT）的 AD。结果表明，在适当的操作条件下可以实现稳定且安全的 AD。共消化可以有效减轻氨抑制的不利影响。与 MMAD 相比，TAcoD 中的甲烷产量增加了 35.86%，同时减少了 43.99%的危险废物。关于 AD 系统的抗药性，庆大霉素被有效降解，降解过程不涉及与修饰酶相关的抗生素抗性基因（ARGs）的表达。在三种操作策略下，有效去除 ARGs 与潜在宿主细菌丰度的更高降低有关。此外，PICRUSt 预测的转化和共轭相关蛋白的变化表明，高温条件和较短的 RT 有利于降低 ARGs 传播风险。
