Spiramycin fermentation residues (SFR) are hazardous wastes enriched with residual antibiotics, yet they can serve as potential feedstocks for resource recovery after appropriate treatment. In this study, SFR-derived biochar (SFR-BC) was produced by pyrolysis and applied to agricultural soil to evaluate its effects on soil properties, microbial communities, potential pathogenic bacteria, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs). A 60-day soil incubation experiment was conducted with one control and three SFR-BC application rates of 0.5%, 1.0%, and 2.0%. SFR-BC improved soil physicochemical properties, nutrient status, enzyme activities, and microbial alpha diversity. Metagenomic analysis showed that SFR-BC altered the abundance of functional genes associated with carbon and nitrogen cycling, indicating shifts in microbial functional potential. SFR-BC also changed bacterial co-occurrence patterns, with the high-dose treatment showing a more complex and highly connected network structure during incubation. In addition, high-dose SFR-BC reduced several potential pathogenic bacteria, including major plant pathogenic taxa. SFR-BC decreased soil ARG abundance by 9.38%-33.67% and MGE abundance by 6.49%-27.89% relative to the control, showing a dose-dependent reduction in antibiotic resistance-related genetic elements. Network and PLS-PM analyses further indicated that ARG variation was statistically associated with soil physicochemical properties, microbial diversity, potential bacterial hosts, and MGEs. Overall, these results suggest that SFR-BC can improve short-term soil nutrient status and reduce ARGs, MGEs, and several potential pathogenic taxa under controlled incubation conditions, providing useful evidence for the potential valorization of antibiotic fermentation residues through pyrolysis.
Yepeng Tian, Jinzhi Sun, Quancheng Shu et al.· Bioresource Technology· 0 citations
As the use of short-chain per- and polyfluoroalkyl substances, particularly perfluorobutane sulfonate (PFBS), continues to increase, their accumulation in wastewater treatment plants (WWTPs) and the associated ecological risks have attracted growing attention. Nevertheless, the impacts of PFBS on the anaerobic ammonium oxidation (anammox) process, as well as its role in the dissemination of antibiotic resistance genes (ARGs) and the proliferation of pathogens, remain poorly understood. In this study, metagenomic analysis combined with multidimensional data integration was employed to systematically investigate the effects of PFBS exposure on anammox performance, microbial metabolism, and ARG dynamics. The results revealed that PFBS exposure significantly deteriorated nitrogen removal, leading to a 10.16% reduction in total nitrogen removal efficiency. Carbon metabolism was inhibited, whereas microbial communities adapted by enhancing antioxidant capacity and electron transport activity. The relative abundance of key anammox functional genes (hzs and hdh) decreased by 54.65% and 57.32%, respectively. Molecular docking analysis demonstrated a strong binding affinity between PFBS and hydrazine dehydrogenase (-8 kcal/mol), suggesting potential interactions. Moreover, PFBS exhibited notable interactions with denitrification-related enzymes, suggesting potential perturbations to denitrification pathways. Additionally, PFBS facilitated the enrichment of ARG and mobile genetic elements (MGE), thereby increasing the potential for MGE-mediated ARG dissemination. PFBS enriched potential pathogenic microorganisms and strengthened their associations with ARGs. Collectively, these findings demonstrate that PFBS exposure compromises anammox performance while simultaneously elevating antimicrobial resistance dissemination and pathogen-associated risks, highlighting its ecological implications in WWTPs.
Yuliang Zhu, Jinlin Guo, Hong-wei Sun et al.· Bioresource Technology· 0 citations
