Dongle Cheng

Intensive livestock production relies heavily on sulfonamides, quinolones and Cu/Zn additives, creating potent co-selective pressures that accelerate the environmental spread of antibiotic-resistance genes (ARGs). This study examined the effects of combined sulfamethoxazole (SMX), ciprofloxacin (CIP), and copper (Cu²⁺) in swine wastewater on microbial fuel cell (MFC) performance and ARGs accumulation. Closed-circuit MFCs achieved 95.9% COD removal in pristine influent, 88-90% under antibiotic stress and 81% when Cu²⁺ was present, while maintaining >99% removal of both SMX and CIP via adsorption and biodegradation. Although Cu²⁺ reduced coulombic efficiency by ~30%, stable electricity generation persisted. Cu²⁺ co-stress doubled class 1 integron abundance and tripled sul, qnr, and cus gene copies relative to antibiotic-only conditions. Anodic polarization enriched electroactive and Cu-tolerant taxa (e.g., Trichococcus and Rhodococcus) associated with ARGs, mobile genetic elements, and metal-resistance genes. PICRUSt2 analysis indicated upregulation of DNA repair, metal efflux, and electron-transfer-related pathways, suggesting functional coupling between bioelectrochemical activity and resistance propagation. These findings demonstrate that while MFCs efficiently remove organic matter and antibiotics, they can simultaneously intensify resistance-gene evolution through quantitative, host-associated and functional mechanisms, highlighting the urgent need for post-treatment barriers or operational optimization to curb ARG dissemination from livestock-wastewater treatment systems.

The emerging contaminant 2, 6-di-tert-butyl-p-cresol (BHT) is a kind of synthetic phenolic antioxidant and can pose negative effects on the aquatic organism. However, the mechanism of phycosphere bacteria coordinating with microalgae in response to BHT stress remains poorly understood. Herein, the effect of BHT on the microalgae Phaeodactylum tricornutum was comprehensively analyzed. BHT exposure led to a dose-dependent inhibition of P. tricornutum growth and the photosynthetic pigment biosynthesis. BHT also led to an increase in the content of malondialdehyde, therefore microalgae responded to the oxidative stress by enhancing activities of antioxidant enzymes, including superoxide dismutase, catalase and peroxidase, to eliminate excess reactive oxygen species in the cells. Furthermore, transcriptome analysis revealed that genes related to photosynthesis, TCA cycle, oxidative phosphorylation, and indole-3-acetic acid (IAA) synthesis were up-regulated in response to BHT stress, which are crucial for the microalgae’s adaptation to stresses. In addition, high-throughput Illumina MiSeq sequencing results demonstrated a significant increase in the relative abundance of bacteria affiliated with Halomonas, Marivita and Oceanicaulis. Microbiological assays demonstrated that Halomonas can thrive by using BHT as the sole energy source and exhibit a chemotactic response to IAA. Therefore, we conclude that the increased content of IAA secreted by microalgae in the phycosphere environment promoted the enrichment of BHT-tolerant bacterium Halomonas, thereby it is helpful for environmental pressures adaptability of P. tricornutum. Overall, this study provided a comprehensive understanding of the physiological and biochemical effects of BHT on microalgae, and we highlight the potential functional significance of IAA in establishing an interaction between microalgae and algae-associated bacteria in adverse environments.

Selenium (Se), a potentially toxic trace element, undergoes complex biogeochemical cycling in the environment, largely driven by microbial activity. The reduction in selenate or selenite to elemental selenium is an environmentally beneficial process, as it decreases both Se toxicity and mobility. This reduction is catalyzed by enzymes encoded by various related genes. The link between Se reduction gene clusters and specific taxonomic groups is significant for elucidating the ecological roles and processes of Se reduction in diverse environments. In this study, a new species of Se-reducing microorganism belonging to the genus Anaerobacillus was isolated from a mining site. A comparative analysis of the growth characteristics reveals that Anaerobacillus species exhibit notable metabolic versatility, particularly in their fermentation abilities and utilization of diverse electron donors and acceptors. Genome analysis identified a diverse array of gene clusters associated with selenate uptake (sul, pst), selenate reduction (ser), and selenite reduction (hig, frd, trx, and bsh). Since selenate reduction is the first crucial step in Se reduction, genes linked to selenate reductase are the focus. The serA gene clusters analysis suggests that the serA gene is highly conserved across Anaerobacillus species. The surrounding genes of serA show significant variability in both presence and gene size. This evolutionary difference in coenzyme utilization and serA regulation suggests distinct survival strategies among Anaerobacillus species. This study offers insights into Se bio-transformations and the adaptive strategies of Se-reducing microorganisms.

Carbon-based materials have attracted significant interest due to their porous structure and high specific surface area. The stability of carbon provides an optimal environment for microbial growth and activity. This paper presents a comprehensive review of microorganisms immobilized on carbon-based materials. Techniques used to immobilize microorganisms on various carbon-based materials are discussed initially. Subsequently, the review introduces the application of these immobilized microorganisms in the restoration of soil and water environments, including the treatment of organic pollutants, heavy metals, and ammonia nitrogen. Overall, this work enhances our understanding of the microbial pathways facilitated by carbon-based materials.