Anaerobic co-digestion of antibiotic fermentation residues and corn stalks for biogas production and elimination of antibiotic resistance genes

• Published in: Fuel (Guildford) 2025-05, Vol.387, p.134442, Article 134442
• Main Authors: Yan, Beibei, Chen, Xin, Wang, Zhi, Li, Jian, Li, Tangwei, Mu, Lan, Chen, Guanyi
• Format: Article
• Language: English
• Subjects: Anaerobic co-digestion; Antibiotic resistance genes; Metabolic Pathway; Metagenomic sequencing
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2025.134442

[Display omitted] •Average daily CH4 production from anaerobic co-digestion reached 132.50 mL/g·VS.•During anaerobic co-digestion, antibiotic resistance genes decreased by 57.84%.•Methanosarcina and Methanospirillum were inhibited by antibiotic resistance genes.•Anaerobic co-digestion promoted the metabolic pathways of the Methane metabolism. Anaerobic digestion represents a disposal technology for antibiotic fermentation residues, which not only mitigates environmental risks but also generates energy. However, monoanaerobic digestion is characterized by operational instability, and the utilization of antibiotic fermentation residues as feedstock inhibits digestion performance, thereby impacting gas production efficiency. Conversely, anaerobic co-digestion can enhance reaction performance by optimizing substrate characteristics, diluting inhibitors, and improving feedstock utilization efficiency. In this study, continuous anaerobic co-digestion of gentamicin mycelial residues with corn stalks was carried out. The methane production performance and system stability were examined. Based on metagenomic sequencing, the changes of microbial communities and antibiotic resistance genes, and the mechanism of their interactions were investigated. The role of anaerobic co-digestion on the metabolic pathway of methane production was also studied. The results showed that average daily methane production from anaerobic co-digestion reached 132.50 mL/g·VS, an increase of 75.40 mL/g·VS over mono-AD. AcoD significantly mitigated the inhibition of AFR on gas production in the system, while also outperforming mono-AD of AFR of gas production efficiency. AcoD had more suitable system environmental parameters and significantly reduced the accumulation of VFAs. AcoD systems are characterized by the presence of more methanogenesis-associated archaea, such as Methanosarcina and Methanospirillum, which would have been suppressed by antibiotic resistance genes. It was shown that ARGs mainly parasitized acid-producing bacteria. There were fewer hosts for ARGs in AcoD system. The expression of almost all functional genes in the methanogenic pathway was enhanced and the abundance of antibiotic resistance genes was reduced by 57.84 %. This work provides an applicable approach for safe treatment of antibiotic fermentation residues and utilize its energy, and also in depth understanding on the key mechanism of microbial and antibiotic resistance genes action by anaerobic co-digestion.