Biodegradation of cephalexin in wastewater by Glutamicibacter sp. S2 and Herbaspirillum sp. S8: Performance, pathway, genomes and synergistic bio-augmentation

作者：Xiaoqing Shan, Zelin Shan, Haijuan Guo, Fang Ma · 发表于：Chemical Engineering Journal · 年份：2025 · DOI：10.1016/j.cej.2025.160783 · 被引用次数：23 · 研究领域：Pharmaceutical and Antibiotic Environmental Impacts、Antibiotic Resistance in Bacteria、Antibiotics Pharmacokinetics and Efficacy

• Glutamicibacter sp. S2 and Herbaspirillum sp. S8 isolated from untamed activated sludge can efficiently degrade cephalexin. • Two functional strains differed in removal ways of cephalexin under different concentrations. • The whole genome of strain S2 and S8 were sequenced, and key degradation enzymes were identified. • Three possible cephalexin degradation pathways were identified. • Microbial consortia constructed by the two functional strains achieved better synergistic bioaugmentation effects. Microbial degradation of β-lactams is an effective bioremediation method. In the present study, Glutamicibacter nicotianae S2 and Herbaspirillum seropedicae S8, capable of effectively biodegrading cephalexin are isolated from untamed activated sludge. Culture parameters are optimized by response surface methodology: 5 % (v/v) dosage, pH 7.5 around, and 30 °C; achieving the maximum cephalexin removal of 84.12 % (S2) and 82.35 % (S8) ultimately. S2 has an excellent ability for biotransformation, while S8 removes cephalexin mainly by adsorption at high initial concentrations. Enzymatic assays reveal that both functional strains are able to produce β-lactamase and the addition of a co-substrate significantly increased the dehydrogenase activity. Combined with whole genome sequencing and LC-Q-TOF-MS analysis of degradation products, genes associated with ring opening hydrolysis, demethylation, and deamination may be involved in the biotransformation of cephalexin. Moreover, twelve poss...