Accelerated biodegradation of BPA in water-sediment microcosms with Bacillus sp. GZB and the associated bacterial community structure

A global metagenomics-based analysis of BPA degradation and its coupling with nitrogen, sulfur, and methane metabolism in landfill leachates

Microbial metabolism in landfill leachate systems is critically important in driving the degradation reactions of organic pollutants, including the emerging pollutant bisphenol A (BPA). However, little research has addressed the microbial degradation of BPA in landfill leachate and its interactions with nitrogen (N), sulfur (S), and methane (CH4) metabolism on a global scale. To this end, in this study on a global scale, an extremely high concentration of BPA was detected throughout the global landfill leachates. Subsequent reconstructive analyses of metagenomic datasets from 113 sites worldwide revealed that the predominant BPA-degrading microflora included Proteobacteria, Firmicutes, and Bacteroidota. Further metabolic analyses revealed that all four biochemical pathways involved in the degradation of BPA were achieved through biochemical cooperation between different bacterial members of the community. In addition, BPA degraders have also been found to actively collaborate synergistically with non-BPA degraders in the N and S removal as well as CH4 catabolism in landfill leachates. Collectively, this study not only provides insights into the dominant microbial communities and specific types of BPA-degrading microbial members in the community of landfill leachates worldwide, but also reveals the synergistic interactions between BPA mineralization and N, S, and CH4 metabolism. These findings offer valuable and important insights for future comprehensive and in-depth investigations into BPA metabolism in different environments.

Biodegradation of phenolic pollutants and bioaugmentation strategies: A review of current knowledge and future perspectives

The widespread use of phenolic compounds renders their occurrence in various environmental matrices, posing ecological risks especially the endocrine disruption effects. Biodegradation-based techniques are efficient and cost-effective in degrading phenolic pollutants with less production of secondary pollution. This review focuses on phenol, 4-nonylphenol, 4-nitrophenol, bisphenol A and tetrabromobisphenol A as the representatives, and summarizes the current knowledge and future perspectives of their biodegradation and the enhancement strategy of bioaugmentation. Biodegradation and isolation of degrading microorganisms were mainly investigated under oxic conditions, where phenolic pollutants are typically hydroxylated to 4-hydroxybenzoate or hydroquinone prior to ring opening. Bioaugmentation efficiencies of phenolic pollutants significantly vary under different application conditions (e.g., increased degradation by 10-95% in soil and sediment). To optimize degradation of phenolic pollutants in different matrices, the factors that influence biodegradation capacity of microorganisms and performance of bioaugmentation are discussed. The use of immobilization strategy, indigenous degrading bacteria, and highly competent exogenous bacteria are proposed to facilitate the bioaugmentation process. Further studies are suggested to illustrate 1) biodegradation of phenolic pollutants under anoxic conditions, 2) application of microbial consortia with synergistic effects for phenolic pollutant degradation, and 3) assessment on the uncertain ecological risks associated with bioaugmentation, resulting from changes in degradation pathway of phenolic pollutants and alterations in structure and function of indigenous microbial community.

Research Progress of Methods for Degradation of Bisphenol A

Bisphenol A (BPA), an endocrine disruptor widely used in industrial production, is found in various environmental sources. Despite numerous reports on BPA degradation and removal, the details remain unclear. This paper aims to address this gap by providing a comprehensive review of BPA degradation methods, focusing on biological, physical, and chemical treatments and the factors that affect the degradation of BPA. Firstly, the paper uses VOSviewer software (version 1.6.15) to map out the literature on BPA degradation published in the past 20 years, which reveals the trends and research focus in this field. Next, the advantages and limitations of different BPA degradation methods are discussed. Overall, this review highlights the importance of BPA degradation to protect the environment and human health. The paper provides significant insights for researchers and policymakers to develop better approaches for BPA degradation and removal.

Biological treatment of triclosan using a novel strain of Enterobacter cloacae and introducing naphthalene dioxygenase as an effective enzyme

In recent years, triclosan (TCS) has been widely used as an antibacterial agent in personal care products due to the spread of the Coronavirus. TSC is an emerging contaminant, and due to its stability and toxicity, it cannot be completely degraded through traditional wastewater treatment methods. In this study, a novel strain of Enterobacter cloacae was isolated and identified that can grow in high TCS concentrations. Also, we introduced naphthalene dioxygenase as an effective enzyme in TCS biodegradation, and its role during the removal process was investigated along with the laccase enzyme. The change of cell surface hydrophobicity during TCS removal revealed that a glycolipid biosurfactant called rhamnolipid was involved in TCS removal, leading to enhanced biodegradation of TCS. The independent variables, such as initial TCS concentration, pH, removal duration, and temperature, were optimized using the response surface method (RSM). As a result, the maximum TCS removal (97%) was detected at a pH value of 7 and a temperature of 32 °C after 9 days and 12 h of treatment. Gas chromatography-mass spectrometry (GC/MS) analysis showed five intermediate products and a newly proposed pathway for TCS degradation. Finally, the phytotoxicity experiment conducted on Cucumis sativus and Lens culinaris seeds demonstrated an increase in germination power and growth of stems and roots in comparison to untreated water. These results indicate that the final treated water was less toxic.

The microbial removal of bisphenols in aquatic microcosms and associated alteration in bacterial community

The concept of the study resulted from numerous concerns around bisphenol A (BPA) and bisphenol S (BPS) in aquatic environments. In this study, river water and sediment microcosms highly polluted with bisphenols and bioaugmented with two BPs-removing bacterial strains were constructed. The study aimed to determine the rate of high-concentrated BPA and BPS (BPs) removal from river water and sediment microniches, and the effect of water bioaugmentation with bacterial consortium on the removal rates of these pollutants. Moreover, the impact of introduced strains and exposure to BPs on the structural and functional composition of the autochthonous bacterial communities was elucidated. Our findings indicate that the removal activity of autochthonous bacteria was sufficient for effectively BPA elimination and reducing BPS content in the microcosms. The number of introduced bacterial cells decreased continuously until day 40, and on consecutive sampling days, no bioaugmented cells were detected. Sequencing analysis of the total 16S rRNA genes revealed that the community composition in bioaugmented microcosms amended with BPs differed significantly from those treated either with bacteria or BPs. A metagenomic analysis found an increase in the abundance of proteins responsible for xenobiotics removal in BPs-amended microcosms. This study provides new insights into the effects of bioaugmentation with a bacterial consortium on bacterial diversity and BPs removal in aquatic environments.

Biological Degradation of Plastics and Microplastics: A Recent Perspective on Associated Mechanisms and Influencing Factors

Plastic and microplastic pollution has caused a great deal of ecological problems because of its persistence and potential adverse effects on human health. The degradation of plastics through biological processes is of great significance for ecological health, therefore, the feasibility of plastic degradation by microorganisms has attracted a lot of attention. This study comprises a preliminary discussion on the biodegradation mechanism and the advantages and roles of different bacterial enzymes, such as PET hydrolase and PCL-cutinase, in the degradation of different polymers, such as PET and PCL, respectively. With a particular focus on their modes of action and potential enzymatic mechanisms, this review sums up studies on the biological degradation of plastics and microplastics related to mechanisms and influencing factors, along with their enzymes in enhancing the degradation of synthetic plastics in the process. In addition, biodegradation of plastic is also affected by plastic additives and plasticizers. Plasticizers and additives in the composition of plastics can cause harmful impacts. To further improve the degradation efficiency of polymers, various pretreatments to improve the efficiency of biodegradation, which can cause a significant reduction in toxic plastic pollution, were also preliminarily discussed here. The existing research and data show a large number of microorganisms involved in plastic biodegradation, though their specific mechanisms have not been thoroughly explored yet. Therefore, there is a significant potential for employing various bacterial strains for efficient degradation of plastics to improve human health and safety.

Occurrence and Distribution of Tetrabromobisphenol A and Diversity of Microbial Community Structure in the Sediments of Mangrove

The occurrence and distribution characteristics of tetrabromobisphenol A (TBBPA) and its relationship with microbial community diversity in different mangrove sediments need further investigation. The results of this study indicated levels of TBBPA in mangrove sediments from the Zhangjiang Estuary (ZJ), Jiulongjiang Estuary (JLJ), and Quanzhou Bay (QZ) in Southeast China ranging from 1.80 to 20.46, 3.47 to 40.77, and 2.37 to 19.83 ng/g dry weight (dw), respectively. Mangrove sediments from JLJ contained higher levels of TBBPA, possibly due to agricultural pollution. A correlation analysis revealed a significant correlation between total organic carbon (TOC), total nitrogen (TN), and TBBPA distribution in ZJ and JLJ mangrove sediments, but not in QZ mangrove sediments. TOC significantly affected the distribution of TBBPA in mangrove sediments, but pH had no effect. High-throughput 16S rRNA gene sequencing showed that Pseudomonadota dominated the sediment bacteria followed by Chloroflexota, Actinobacteota, Bacillota, Acidobacteriota, Bacteroidota, and Aminicenantes in mangrove sediments. Although the microbial community structure of the ZJ, JLJ, and QZ mangrove sediments was similar, the taxonomic profile of their sensitive responders differed markedly. The genus Anaerolinea was dominant in the mangrove sediments and was responsible for the in situ dissipation of TBBPA. Based on redundancy analysis, there was a correlation between TBBPA, TOC, TN, C/N, pH, and microbial community structure at the genus level. Combining TBBPA, TN, and TOC may induce variations in the microbial community of mangrove sediments.

Performance and mechanism of a novel S-scheme heterojunction sonocatalyst CuS/BaWO4 for degradation of bisphenol A by ultrasonic activation

A novel CuS/BaWO₄ heterojunction catalyst was prepared and characterized. Taking bisphenol A as the target pollutant for catalytic degradation, the sonocatalytic activity of CuS/BaWO₄ composite was evaluated, and the combination with persulfate improved the sonocatalytic degradation of bisphenol A. The results showed that CuS/BaWO₄ composite had good sonocatalytic degradation activity for bisphenol A, and the degradation rate was 70.99% ± 1.46%. After combined with persulfate, the degradation rate was further increased to 95.34% ± 0.10%, and the reaction time was relatively shortened. The results of the trapping experiment and calculated energy band positions showed that the formation of S-scheme heterojunction and the formation of hydroxyl radicals and holes were the key to the catalytic degradation of bisphenol A by CuS/BaWO₄ composite. In this study, a new CuS/BaWO₄ heterojunction sonocatalyst was synthesized. The catalyst can efficiently remove bisphenol A from the water environment and can be used as a potential solution for endocrine disruptor pollution in the water environment.

Accelerated degradation of cellulose in silkworm excrement by the interaction of housefly larvae and cellulose-degrading bacteria

The environmental pollution caused by silkworm (Bombyx mori) excrement is prominent, and rich in refractory cellulose is the bottleneck restricting the efficient recycling of silkworm excrement. This study was performed to investigate the effects of housefly larvae vermicomposting on the biodegradation of cellulose in silkworm excrement. After six days, a 58.90% reduction of cellulose content in treatment groups was observed, which was significantly higher than 11.5% of the control groups without housefly larvae. Three cellulose-degrading bacterial strains were isolated from silkworm excrement, which were identified as Bacillus licheniformis, Bacillus amyloliquefaciens, and Bacillus subtilis based on 16S rRNA gene sequence analysis. These three bacterial stains had a high cellulose degradation index (HC value ranged to between 1.86 and 5.97 and FPase ranged from 5.07 U/mL to 7.31 U/mL). It was found that housefly larvae increased the abundance of cellulose-degrading bacterial genus (Bacillus and Pseudomonas) by regulating the external environmental conditions (temperature and pH). Carbohydrate metabolism was the bacterial communities' primary function during vermicomposting based on the PICRUSt. The results of Tax4Fun indicated that the abundance of endo-β-1,4-glucanase and exo-β-1,4-glucanase increased rapidly and maintained at a higher level in silkworm excrement due to the addition of housefly larvae, which contributed to the accelerated degradation of cellulose in silkworm excrement. The finding of this investigation showed that housefly larvae can significantly accelerate the degradation of cellulose in silkworm excrement by increasing the abundance of cellulose-degrading bacterial genera and cellulase.

Bacterial degradation of bisphenol analogues: an overview

Bisphenol A (BPA) is one of the most produced synthetic monomers in the world and is widespread in the environment. BPA was replaced by bisphenol analogues (BP) because of its adverse effects on life. Bacteria can degrade BPA and other bisphenol analogues (BP), diminishing their environmental concentrations. This study aimed to summarize the knowledge and contribute to future studies. In this review, we surveyed papers on bacterial degradation of twelve different bisphenol analogues published between 1987 and June 2022. A total of 102 original papers from PubMed and Google Scholar were selected for this review. Most of the studies (94.1%, n = 96) on bacterial degradation of bisphenol analogues focused on BPA, and then on bisphenol F (BPF), and bisphenol S (BPS). The number of studies on bacterial degradation of bisphenol analogues increased more than six times from 2000 (n = 2) to 2021 (n = 13). Indigenous microorganisms and the genera Sphingomonas, Sphingobium, and Cupriavidus could degrade several BP. However, few studies focussed on Cupriavidus. The acknowledgement of various aspects of BP bacterial biodegradation is vital for choosing the most suitable microorganisms for the bioremediation of a single BP or a mixture of BP.

Trends and thresholds on bacterial degradation of bisphenol-A endocrine disruptor - a concise review

Bisphenol-A (BPA) is a monomer found in polycarbonate plastics, food cans, and other everyday chemicals; this monomer and its counterparts are widely used, culminating in its presence in water, soil, sediment, and the atmosphere. Furthermore, because of its estrogenic and genotoxic properties, it has been acknowledged as an endocrine disruptor; contamination of BPA in the environment is becoming a growing concern, and ways to effectively mitigate BPA from the environment are currently explored. Hence, the focal point of the review is to collate the bacterial degradation of BPA with the proposed degradation mechanism, explicitly focusing on researches published between 2017 and 2022. BPA breakdown is dependent primarily on bacterial metabolism, although numerous factors influence its fate in the environment. The metabolic routes for BPA breakdown in crucial bacterial strains were postulated, sourced on the transformed metabolite-intermediates perceived through degradation; enzymes and genes associated with the bacterial degradation of BPA have also been included in this review. This review will be momentous to generate a conceptual strategy and stimulate the progress on bacterial mitigation of BPA as a path to a sustainable cleaner environment.

Stable isotope probing reveals specific assimilating bacteria of refractory organic compounds in activated sludge

Activated sludge in wastewater treatment bioreactors contains diverse bacteria, while little is known about the community structure of bacteria responsible for degradation of refractory organic compounds (ROCs). In this study, 10 ROCs frequently detected in sewage were investigated, and the potential bacteria degrading these ROCs were analyzed by DNA stable isotope probing and high-throughput sequencing. The results showed that the bacterial communities responsible for degradation of different ROCs were largely different. A total of 84 bacterial genera were found to be involved in degrading at least one of the 10 ROCs, however, only six genera (Acinetobacter, Bacteroides, Bosea, Brevundimonas, Lactobacillus and Pseudomonas) were common to all 10 ROCs. This suggests that different ROCs may have specific assimilating bacteria in the activated sludge. Our results also showed that these ROC-degrading bacteria are difficult to isolate by conventional methods and that most of them have relatively low relative abundance in municipal wastewater treatment bioreactors. Development of new technologies to increase the abundance and activity of these bacteria may significantly improve the removal efficiency of ROCs from wastewater.

Enhanced periphyton biodegradation of endocrine disrupting hormones and microplastic: Intrinsic reaction mechanism, influential humic acid and microbial community structure elucidation

Endocrine-disrupting compounds (EDCs), as well as microplastics, have drawn global attention due to their presence in the aquatic ecosystem and persistence in wastewater treatment plants (WWTPs). In the present study, for simultaneous bio-removal of two EDCs, 17α-ethinylestradiol (EE2), bisphenol A (BPA), and a microplastic, polypropylene (PP) four kinds of periphytic biofilms were employed. Additionally, the effect of humic acid (HA) on the removal efficacy of these biofilms was evaluated. It was observed that EE2 and BPA (0.2 mg L^-1 each) were completely (∼100%) removed within 36 days of treatment; and the biodegradation of EE2, BPA, and PP was significantly enhanced in the presence of HA. Biodegradation of EE2 and BPA was evaluated through Ultra-high performance liquid chromatography (UHPLC), and Gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) was used to determine the mechanism of degradation. Gel permeation chromatography (GPC) and SEM had validated the biodegradation of PP (5.2-14.7%). MiSeqsequencing showed that the community structure of natural biofilm changed after the addition of HA, as well as after the addition of EDCs and PP. This change in community structure might be a key factor regarding variable biodegradation percentages. The present study revealed the potential of periphytic biofilms for the simultaneous removal of pollutants of different chemical natures, thus provides a promising new method for wastewater treatment applications.

Metagenomic analysis of microbial communities continuously exposed to Bisphenol A in mangrove rhizosphere and non-rhizosphere soils

Bisphenol A (BPA) is widely distributed in littoral zones and may cause adverse impacts on mangrove ecosystem. Biodegradation and phytoremediation are two primary processes for BPA dissipation in mangrove soils. However, the rhizosphere effects of different mangrove species on BPA elimination are still unresolved. In this study, three typical mangrove seedlings, namely Avicennia marina, Bruguiera gymnorrhiza (L.) and Aegiceras corniculatum, were cultivated in soil microcosms for four months and then subjected to 28-day continuous BPA amendment. Un-planted soil microcosms (as control) were also set up. The BPA residual rates and root exudates were monitored, and the metabolic pathways as well as functional microbial communities were also investigated to decipher the rhizosphere effects based on metagenomic analysis. The BPA residual rates in all planted soils were significantly lower than that in un-planted soil on day 7. Both plantation and BPA dosage had significant effects on bacterial abundance. A distinct separation of microbial structure was found between planted and un-planted soil microcosms. Genera Pseudomonas and Lutibacter got enriched with BPA addition and may play important roles in BPA biodegradation. The shifts in bacterial community structure upon BPA addition were different among the microcosms with different mangrove species. Genus Novosphingobium increased in Avicennia marina and Bruguiera gymnorrhiza (L.) rhizosphere soils but decreased in Aegiceras corniculatum rhizosphere soil. Based on KEGG annotation and binning analysis, the proposal of BPA degradation pathways and the quantification of relevant functional genes were achieved. The roles of Pseudomonas and Novosphingobium may differ in lower BPA degradation pathways. The quantity variation patterns of functional genes during the 28-day BPA amendment were different among soil microcosms and bacterial genera.

Bisphenol A Removal by the Fungus Myrothecium roridumIM 6482-Analysis of the Cellular and Subcellular Level

Bisphenol (BPA) is a key ingredient in the production of epoxy resins and some types of plastics, which can be released into the environment and alter the endocrine systems of wildlife and humans. In this study, the ability of the fungus M. roridumIM 6482 to BPA elimination was investigated. LC-MS/MS analysis showed almost complete removal of BPA from the growth medium within 72 h of culturing. Products of BPA biotransformation were identified, and their estrogenic activity was found to be lower than that of the parent compound. Extracellular laccase activity was identified as the main mechanism of BPA elimination. It was observed that BPA induced oxidative stress in fungal cells manifested as the enhancement in ROS production, membranes permeability and lipids peroxidation. These oxidative stress markers were reduced after BPA biodegradation (72 h of culturing). Intracellular proteome analyses performed using 2-D electrophoresis and MALDI-TOF/TOF technique allowed identifying 69 proteins in a sample obtained from the BPA containing culture. There were mainly structural and regulator proteins but also oxidoreductive and antioxidative agents, such as superoxide dismutase and catalase. The obtained results broaden the knowledge on BPA elimination by microscopic fungi and may contribute to the development of BPA biodegradation methods.

Enhanced removal of bisphenol A using pine-fruit shell-derived hydrochars: Adsorption mechanisms and reusability

We synthesized NaOH-activated hydrochars via hydrothermal carbonization (HTC) of Brazilian pine fruit shells at HTC residence times of 24, 48, and 72 h. The hydrochars were used as adsorbents to remove bisphenol A (BPA) from aqueous solutions. The surface area of the samples can reach up to 2220 m² g^-1, and the maximum adsorption of BPA onto the surfaces was achieved at a pH of 7.0 (708 mg g^-1). Adsorption occurred mainly via monolayer formation with a low retention time of the adsorbate (τ) on the surfaces, indicating that the BPA molecules reached the already occupied active sites and returned after undergoing heat exchange (τ > 0). Adsorption is an endothermic spontaneous process that results in a balance between entropic and enthalpic contributions. In such a reaction, ΔG°< 0, even with ΔH°> 0, the process occurs with an important increase in the entropy. The desorption was more efficient with ethanol and methanol than with HCl, NaOH, and NaCl owing to the dipole-dipole forces between the adsorbate and the alcohols. Additionally, the low desorption efficiency using acid, base, and salts can be attributed to competitive effects between the desorption agents and the active sites of the adsorbents.

Sediments in the mangrove areas contribute to the removal of endocrine disrupting chemicals in coastal sediments of Macau SAR, China, and harbour microbial communities capable of degrading E2, EE2, BPA and BPS

The occurrence of endocrine disrupting chemicals (EDCs) is a major issue for marine and coastal environments in the proximity of urban areas. The occurrence of EDCs in the Pearl River Delta region is well documented but specific data related to Macao is unavailable. The levels of bisphenol-A (BPA), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (E2), estriol (E3), and 17α-ethynylestradiol (EE2) were measured in sediment samples collected along the coastline of Macao. BPA was found in all 45 collected samples with lower BPA concentrations associated to the presence of mangrove trees. Biodegradation assays were performed to evaluate the capacity of the microbial communities of the surveyed ecosystems to degrade BPA and its analogue BPS. Using sediments collected at a WWTP discharge point as inoculum, at a concentration of 2 mg l^-1 complete removal of BPA was observed within 6 days, whereas for the same concentration BPS removal was of 95% after 10 days, which is particularly interesting since this compound is considered recalcitrant to biodegradation and likely to accumulate in the environment. Supplementation with BPA improved the degradation of bisphenol-S (BPS). Aiming at the isolation of EDCs-degrading bacteria, enrichments were established with sediments supplied with BPA, BPS, E2 and EE2, which led to the isolation of a bacterial strain, identified as Rhodoccoccus sp. ED55, able to degrade the four compounds at different extents. The isolated strain represents a valuable candidate for bioremediation of contaminated soils and waters.

Evaluation of Oxidative stress, antioxidant enzymes and genotoxic potential of bisphenol A in fresh water bighead carp (Aristichthys nobils) fish at low concentrations

Bisphenol A (BPA) is one of the emerging contaminants associated with deleterious health effects on both public and wildlife and is extensively incorporated into different industrial products. Therefore, the current trial was conducted to determine the oxidative stress, status of different antioxidant enzymes and genotoxic potential of bisphenol A in fresh water fish at low concentrations. For this purpose, a total of 80 fresh water bighead carp (Aristicthys nobilis) received from commercial fish center were randomly divided and kept in four groups (A-D). Fish in groups (B-D) were exposed to different levels of BPA for a period of 60 days while fish of group A served as control group. Treated fish exhibited different physical and behavioral ailments in a time and treatment manners. Results showed significantly (p < 0.05) increased quantity of different oxidative stress biomarkers such as thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH) and the contents of reactive oxygen species (ROS) in gills, liver, kidneys and brain of exposed fish. Concentration of different antioxidant enzymes like catalase, superoxide dismutase, peroxidase and total proteins was significantly (p < 0.05) decreased in gills, liver, kidneys and brain of exposed fish. Results showed significantly (p < 0.05) increased frequency of morphological alterations, nuclear changes in red blood cells and increased DNA damage potential of bisphenol A in gills, liver, kidneys and brain tissues. The current trial concludes that even at very low concentrations bisphenol A causes toxic effects via turbulences in physiological and biochemical parameters in multiple tissues of fish.

A comprehensive study on bisphenol A degradation by newly isolated strains Acinetobacter sp. K1MN and Pseudomonas sp. BG12

Bisphenol A (BPA) is an endocrine disrupting chemical. Its extensive use has led to the wide occurrence of BPA in various environmental ecosystems, at levels that may cause negative effects to the ecosystem and public health. Although there are many bacteria able to BPA utilization, only a few of them have a strong capacity for its biodegradation. Therefore, it is important to search for new bacteria strains, investigate their BPA biodegradation ability and potential effect of pH and other organic compounds on the process. These tasks have become the object of the present study. The results of our research show that for the newly isolated strains Acinetobacter sp. K1MN and Pseudomonas sp. BG12 after 15 days, with an initial BPA concentration of 100 mg L^− 1, the highest BPA removal was achieved at pH 8, while sodium glutamate as a biostimulant best accelerated BPA degradation. Kinetic data for BPA biodegradation by both strains best fitted the Monod model. The specific degradation rate and the half saturation constant were estimated respectively as 8.75 mg L^− 1 day^− 1 and 111.27 mg L^− 1 for Acinetobacter sp. K1MN, and 8.6 mg L^− 1 day^− 1 and 135.79 mg L^− 1 for Pseudomonas sp. BG12. The half-maximal effective concentration (EC₅₀) of BPA for Acinetobacter sp. K1MN was 120 mg L^− 1 and for Pseudomonas sp. BG12 it was 123 mg L^− 1. The toxicity bioassay (Microtox test) showed that elimination of BPA by both strains is accompanied by reduction of its toxic effect. The ability of tested strains to degrade BPA combined with their high resistance to this xenobiotic indicates that Acinetobacter sp. K1MN and Pseudomonas sp. BG12 are potential tools for BPA removal during wastewater treatment plant.

Combined effects of electrical current and nonsteroidal antiinflammatory drugs (NSAIDs) on microbial community in a three-dimensional electrode biological aerated filter (3DE-BAF)

Three-dimensional electrode biological aerated filter (3DE-BAF) with particulate bioelectrode from lithium slag was used to simultaneously remove diclofenac and clofibric acid from the synthetic domestic sewage, and the combined effects of electrical current and nonsteroidal antiinflammatory drugs (NSAIDs) on microbial community was analyzed. The results indicated that (1) the average diclofenac and clofibric acid removal efficiency in the 3DE-BAF firstly increased, attained the peak of 79.40 ± 6.74% and 69.50 ± 6.26% at 0.35 A, and then decreased to 71.82 ± 4.90% and 55.92 ± 5.17% at 0.40 A, respectively; (2) the concentration of the diclofenac and clofibric acid in 3DE-BAF gradually decreased with the increase of reactor height; (3) the current intensity and space position affected the microbial structure at the different level; (4) at the optimum current intensity, Thiothrix, Flavobacteriaceae, Halothiobacillaceae, Hydrogenophaga, and Comamonadaceae accounted for the main bacterial community for removal diclofenac and clofibric acid in the 3DE-BAF.

Kerr P, Ali S, Sultana N, Jia Z. Multifunctional Periphytic Biofilms: Polyethylene Degradation and Cd2+ and Pb2+ Bioremediation under High Methane Scenario

Priority pollutants such as polyethylene (PE) microplastic, lead (Pb²⁺), and cadmium (Cd²⁺) have attracted the interest of environmentalists due to their ubiquitous nature and toxicity to all forms of life. In this study, periphytic biofilms (epiphyton and epixylon) were used to bioremediate heavy metals (HMs) and to biodegrade PE under high (120,000 ppm) methane (CH₄) doses. Both periphytic biofilms were actively involved in methane oxidation, HMs accumulation and PE degradation. Epiphyton and epixylon both completely removed Pb²⁺ and Cd²⁺ at concentrations of 2 mg L⁻¹ and 50 mg L⁻¹, respectively, but only partially removed these HMs at a relatively higher concentration (100 mg L⁻¹). Treatment containing 12% ¹³CH₄ proved to be most effective for biodegradation of PE. A synergistic effect of HMs and PE drastically changed microbial biota and methanotrophic communities. High-throughput 16S rRNA gene sequencing revealed that Cyanobacteria was the most abundant class, followed by Gammaproteobacteria and Alphaproteobacteria in all high-methane-dose treatments. DNA stable-isotope probing was used to label ¹³C in a methanotrophic community. A biomarker for methane-oxidizing bacteria, pmoA gene sequence of a ¹³C-labeled fraction, revealed that Methylobacter was most abundant in all high-methane-dose treatments compared to near atmospheric methane (NAM) treatment, followed by Methylococcus. Methylomonas, Methylocystis, Methylosinus, and Methylocella were also found to be increased by high doses of methane compared to NAM treatment. Overall, Cd⁺² had a more determinantal effect on methanotrophic activity than Pb²⁺. Epiphyton proved to be more effective than epixylon in HMs removal and PE biodegradation. The findings proved that both epiphyton and epixylon can be used to bioremediate HMs and biodegrade PE as an efficient ecofriendly technique under high methane concentrations.

Proteomic mechanism of decabromodiphenyl ether (BDE-209) biodegradation by Microbacterium Y2 and its potential in remediation of BDE-209 contaminated water-sediment system

The investigation of BDE-209 degradation by Microbacterium Y2 under different condition was conducted. Cell membrane permeability, cell surface hydrophobicity (CSH), membrane potential (MP) and reactive oxygen species (ROS) production were altered under BDE-209 stress. Eleven debrominated congeners were identified, suggesting that BDE-209 biodegradation by Microbacterium Y2 was dominantly a successive debromination process. Proteome analysis showed that the overexpression of haloacid dehalogenases, glutathione S-transferases (GSTs) and ATP-binding cassette (ABC) transporters might occupy important roles in BDE-209 biotransformation. Meanwhile, heat shock proteins (HSPs), ribonuclease E, oligoribonuclease (Orn) and ribosomal protein were activated to counter the BDE-209 toxicity. The up-regulated pyruvate dehydrogenase E1 component beta subunit and dihydrolipoamide dehydrogenase suggested that the pyruvate metabolism pathway was activated. Bioaugmentation of BDE-209 polluted water-sediments system with Microbacterium Y2 could efficiently improve BDE-209 removal. The detection of total 16S rRNA genes in treatment system suggested that Microbacterium (25.6 %), Luteimonas (14.3 %), Methylovorus (12.6 %), Hyphomicrobium (9.2 %) were the dominant genera and PICRUSt results further revealed that the diminution of BDE-209 was owed to cooperation between the introduced bacteria and aboriginal ones.

Effect of mangrove species on removal of tetrabromobisphenol A from contaminated sediments

The increase levels of tetrabromobisphenol A (TBBPA) in mangrove wetlands is of concern due to its potential toxic impacts on ecosystem. A 93-day greenhouse pot experiment was conducted to investigate the effects of mangrove plants, A. marina and K. obovata, on TBBPA degradation in sediment and to reveal the associated contributing factor(s) for its degradation. Results show that both mangrove species could uptake, translocate, and accumulate TBBPA from mangrove sediments. Compared to the unplanted sediment, urease and dehydrogenase activity as well as total bacterial abundance increased significantly (p < 0.05) in the sediment planted with mangrove plants, especially for K. obovata. In the mangrove-planted sediment, the Anaerolineae genus was the dominant bacteria, which has been reported to enhance TBBPA dissipation, and its abundance increased significantly in the sediment at early stage (0-35 day) of the greenhouse experiment. Compared to A. marina-planted sediment, higher enrichment of Geobater, Pseudomonas, Flavobacterium, Azoarcus, all of which could stimulate TBBPA degradation, was observed for the K. obovata-planted sediment during the 93-day growth period. Our mass balance result has suggested that plant-induced TBBPA degradation in the mangrove sediment is largely due to elevated microbial activities and total bacterial abundance in the rhizosphere, rather than plant uptake. In addition, different TBBPA removal efficiencies were observed in the sediments planted with different mangrove species. This study has demonstrated that K. obovata is a more suitable mangrove species than A. marina when used for remediation of TBBPA-contaminated sediment.

Housefly larvae (Musca domestica) significantly accelerates degradation of monensin by altering the structure and abundance of the associated bacterial community

Vermicomposting of livestock manure using housefly larvae is a promising biotechnology for waste reduction and control of antibiotic pollution. Monensin (MON), an ionophore polyether antibiotic (IPA), is widely used in broiler feed to control coccidiosis. However, MON residues in litter have become a major source of pollution in the environment. In this work, we studied the efficiency of housefly larvae (Musca domestica) on monensin attenuation during a 12-day laboratory scale vermicomposting experiment. We observed a 94.99% reduction in MON concentration after four days in treatment groups, while it took twelve days to remove more than 94.71% of MON in the control group. We found that the bacterial community composition of the substrate was reshaped by housefly larvae. From the treatment groups, three MON-degrading bacterial strains were isolated and identified as Acinetobacter sp., Stenotrophomonas sp. and Alcaligenes sp. based on 16 S rRNA gene sequence analysis. These three strains were among dominant the bacteria in treated substrates, showing between 52.80% and 89.25% degradation of MON in mineral salt medium within 28 days. Furthermore, two MON-degrading bacteria (Stenotrophomonas sp. and Alcaligenes sp.) were more abundant in treatment groups and larvae gut groups compared with those in control groups. The abundance enhancement of MON-degrading bacteria was related to the change in ambient temperature and pH in the substrates, which were affected by housefly larvae activities. Our results confirm that housefly larvae can significantly accelerate degradation of MON in chicken manure by increasing the abundance of MON-degrading bacteria.

Bisphenols: Application, occurrence, safety, and biodegradation mediated by bacterial communities in wastewater treatment plants and rivers

Numerous data indicate that most of bisphenols (BPs) are endocrine disrupters and exhibit cytotoxicity, neurotoxicity, genotoxicity and reproductive toxicity against vertebrates. Nevertheless, they are widely applied in material production what result in their ubiquitous occurrence in ecosystems. While BPA is the most frequently detected in environment, BPAF, BPF and BPS are also often found. Ecosystem particularly exposed to BPs pollution is industrial and municipal wastewater being a common source of BPA in river waters. Different techniques to remove BPs from these ecosystems have been applied, among which biodegradation seems to be the most effective. In this review the current state of knowledge in the field of BPs application, distribution in the environment, effects on animal and human health, and biodegradation mediated by bacterial populations in wastewater treatment plants and rivers is presented.

Enhanced phytoremdiation of Robinia pseudoacacia in heavy metal-contaminated soils with rhizobia and the associated bacterial community structure and function

Heavy metals can cause serious contamination of soils, especially in mining regions. A detailed understanding of the effects of heavy metals on plants and root-associated microbial communities could help to improve phytoremediation systems. In this study, black locust (Robinia pseudoacacia) seedlings with or without rhizobial inoculation were planted in soils contaminated with different levels of heavy metals. Bacterial communities in rhizosphere and bulk soil samples were analyzed using 16S rRNA gene sequencing on the Illumina MiSeq platform and shotgun metagenome sequencing on the Illumina HiSeq platform. Soil bacterial communities varied significantly depending on the level of soil contamination, and planting also had some influence. Although inoculation of Mesorhizobium loti HZ76 (a natural microsymbiont of R. pseudoacacia) was a relatively minor factor, it did influence the soil bacterial community. Under the selective pressure, plant growth promotion-related biomarkers in the rhizosphere increased after inoculation compared with non-inoculated controls, especially those associated with Mesorhizobium, Variovorax, Streptomyces, and Rhodococcus genera. Genes encoding ATP-binding cassette transporters were up-regulated in the rhizosphere after inoculation compared with genes related to sulfur/nitrogen metabolism. These results provide insight into soil bacterial communities and their functions in the R. pseudoacacia rhizosphere in response to rhizobial inoculation and heavy metal contamination. This knowledge may prove useful for improving phytoremediation of metal-contaminated soils.