Aerobic and anaerobic degradation of BDE-47 by facultative anaerobe Pseudomonas sp. QS-1: Pathway, product toxicity, and bio-augmentation remediation

Although microbial degradation has been extensively studied for removing 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47), knowledge regarding the comparative efficiency and safety of degradation by facultative anaerobes under varying oxygen conditions remain limited. This study investigated the degradation of BDE-47 by Pseudomonas sp. strain QS-1 under both aerobic and anaerobic conditions. Our findings revealed that 47.5% and 12.4% of the initially added BDE-47 (0.5 mg/L) were transformed within 7 days under aerobic and anaerobic conditions, respectively. The aerobic transformation involved a complex pathway consisting of debromination, hydroxylation, ether bond cleavage, and ring opening, whereas the anaerobic transformation was limited to debromination. Toxicity assessments using an Escherichia coli model revealed that aerobic degradation products reduced cytotoxicity, whereas anaerobic degradation products induced higher rates of cell apoptosis than the parent BDE-47. Metabolomics analysis attributed this enhanced toxicity of anaerobic products to the specific inhibition of purine metabolism. In soil microcosm experiments, strain QS-1 exhibited stronger colonization and degradation performance under aerobic conditions, shifting the soil microbial community assembly towards more deterministic processes and strengthening network interactions with indigenous taxa. These findings provide insights into the biological effects of BDE-47 degradation products, and inform the assessment of efficacy and safety for bioremediation strategy. Download: Download high-res image (175KB) Download: Download full-size image