National-Local Joint Engineering Research Center for Biomass Refining and High-Quality Utilization, Institute of Urban and Rural Mining, Changzhou University, Changzhou, 213164, China.
State Environmental Protection Engineering Center for Harmless Treatment and Resource Utilization of Antibiotic Residues, Yili Chuanning Biotechnology Co., Ltd., Yili, 835007, China.
Environ Pollut. 2021 Dec 1;290:118075. doi: 10.1016/j.envpol.2021.118075. Epub 2021 Aug 31.
Combining hydrothermal treatment and composting is an effective method to dispose of penicillin fermentation residue (PFR), but the safety and related mechanism are still unclear. In this study, penicillin solution was hydrothermally treated to decipher its degradation mechanism, and then hydrothermally treated PFR (HT-PFR) was mixed with bulking agents at ratios of 2:0 (CK), 2:1.5 (T1), and 2:5 (T2) to determine the absolute abundance of antibiotic resistance genes (ARGs) and the succession of bacterial community. Results showed that penicillin was degraded to several new compounds without the initial lactam structure after hydrothermal treatment. During composting, temperature and pH of the composts increased with the raising of HT-PFR proportion, except the pH at days 2. After 52 days of composting, the absolute copies of ARGs (blaTEM, blaCMY2, and blaSFO) and the relative abundance of bacteria related to pathogens were reduced significantly (P < 0.05). Especially, the total amount of ARGs in the samples of CK and T1 were decreased to equal level (around 5 log copies/g), which indicated that more ARGs were degraded in the latter by the composting process. In the CK samples, Bacteroidetes and Proteobacteria accounted for ~69.8% of the total bacteria, but they were gradually replaced by Firmicutes with increasing proportions of HT-PFR, which can be caused by the high protein content in PFR. Consisting with bacterial community, more gram-positive bacteria were observed in T1 and T2, and most of them are related to manganese oxidation and chitinolysis. As composting proceeded, bacteria having symbiotic or pathogenic relationships with animals and plants were reduced, but those related to ureolysis and cellulolysis were enriched. Above all, hydrothermal treatment is effective in destroying the lactam structure of penicillin, which makes that most ARGs and pathogenic bacteria are eliminated in the subsequent composting.
将水热处理与堆肥相结合是处理青霉素发酵残渣（PFR）的有效方法，但安全性及其相关机制仍不清楚。在本研究中，对青霉素溶液进行水热处理以解析其降解机制，然后将水热处理的 PFR（HT-PFR）与膨松剂以 2:0（CK）、2:1.5（T1）和 2:5（T2）的比例混合，以确定抗生素抗性基因（ARGs）的绝对丰度和细菌群落的演替。结果表明，青霉素经水热处理后降解为几种初始无内酰胺结构的新化合物。在堆肥过程中，除第 2 天外，随着 HT-PFR 比例的升高，堆肥的温度和 pH 值均升高。堆肥 52 天后，ARGs（blaTEM、blaCMY2 和 blaSFO）的绝对拷贝数和与病原体相关的细菌的相对丰度显著降低（P < 0.05）。特别是 CK 和 T1 样品中 ARGs 的总量减少到相同水平（约 5 log 拷贝/g），这表明在堆肥过程中，更多的 ARGs 在后者中被降解。在 CK 样品中，Bacteroidetes 和 Proteobacteria 占总细菌的~69.8%，但随着 HT-PFR 比例的增加，逐渐被Firmicutes取代，这可能是由于 PFR 中的高蛋白含量所致。与细菌群落一致，T1 和 T2 中观察到更多的革兰氏阳性菌，其中大多数与锰氧化和几丁质分解有关。随着堆肥的进行，与动植物具有共生或致病关系的细菌减少，但与脲解和纤维素分解有关的细菌得到了富集。综上所述，水热处理有效地破坏了青霉素的内酰胺结构，使得大多数 ARGs 和致病菌在随后的堆肥中被消除。
