Aerobic Degradation Characteristics of Decabromodiphenyl ether through Rhodococcus ruber TAW-CT127 and Its Preliminary Genome Analysis

Identification of phenols and their formation network during the brewing process of Shanxi aged vinegar

Phenols are important functional compounds present in vineagr, however, their composition and formation pathways remain uncertain. Herein, non-targeted metabolomics and macrotranscriptomics methods were applied to identify phenols and analyze their formation network during the brewing process of Shanxi aged vinegar. A total of 82 phenols were detected from the raw material and the brewing process. Results indicated that phenolic acids were the major phenols and were mainly formed during acetic acid fermentation stages. Water, reducing sugars, lactic acid, and 7 amino acids influenced the formation and transformation of phenols, as shown through Spearman analysis. Furthermore, 16 genera and 38 enzymes were involved in substrates decomposition and phenols formation according to the metabolic pathway analysis, with Xenobiotics biodegradation and metabolism identified as the main pathway for phenols formation. Lactobacillus and Acetobacter were the key genera responsible for the phenols transformation. This study provides new insights into the phenols formation mechanisms in cereal vinegars and it is helpful for isolating the functional strains to reinforce the phenols formation.

Debromination of decabromodiphenyl ether (BDE-209) and bacterial community responses in aerobic and anaerobic soil microcosms

Polybrominated diphenyl ethers (PBDEs) are a class of persistent organic pollutants that may pose risks to human health and environmental biota, including soil microbial communities. These risks are further affected by a multitude of factors, including environmental conditions encountered in real-world settings. A comprehensive understanding of how PBDEs transform and microbial communities respond to the exposure under varying environmental conditions is paramount for assessing the ecological risks or identifying potential degraders. In this study, soil microcosms spiked with or without 10 mg kg-1 decabromodiphenyl ether (BDE-209) were established and incubated under either aerobic or anaerobic conditions for a duration of up to 180 days. The results demonstrated mono- to nine-brominated PBDE congeners accounted for approximately 4.03 % and 6.18 % of the initial concentration of BDE-209 added to the soil in both aerobic and anaerobic conditions, respectively. Anaerobic microcosms demonstrated faster and deeper debromination compared to the aerobic microcosms. Bacterial communities were monitored during the incubation to evaluate the community succession under the PBDE stress. Oxygen significantly shaped the richness, diversity, composition, and network complexity of soil bacterial community. BDE-209 had profound impacts on the network structure of bacterial communities. Random Forest model identified Desulfosporosinus and Polaromonas that might be related to BDE-209 debromination under anaerobic conditions. Overall, our findings shed light on the bacterial community effects of BDE-209 in aerobic or anaerobic soils, thus providing a theoretical basis for remediation of soil contaminated by PBDEs.

A critical review on BDE-209: Source, distribution, influencing factors, toxicity, and degradation

As the most widely used polybrominated diphenyl ether, BDE-209 is commonly used in polymer-based commercial and household products. Due to its unique physicochemical properties, BDE-209 is ubiquitous in a variety of environmental compartments and can be exposed to organisms in various ways and cause toxic effects. The present review outlines the current state of knowledge on the occurrence of BDE-209 in the environment, influencing factors, toxicity, and degradation. BDE-209 has been detected in various environmental matrices including air, soil, water, and sediment. Additionally, environmental factors such as organic matter, total suspended particulate, hydrodynamic, wind, and temperature affecting BDE-209 are specifically discussed. Toxicity studies suggest BDE-209 may cause systemic toxic effects on living organisms, reproductive toxicity, embryo-fetal toxicity, genetic toxicity, endocrine toxicity, neurotoxicity, immunotoxicity, and developmental toxicity, or even be carcinogenic. BDE-209 has toxic effects on organisms mainly through epigenetic regulation and induction of oxidative stress. Evidence regarding the degradation of BDE-209, including biodegradation, photodegradation, Fenton degradation, zero-valent iron degradation, chemical oxidative degradation, and microwave radiation degradation is summarized. This review may contribute to assessing the environmental risks of BDE-209 to help develop rational management plans.