Soil Microbiome Response to Contamination with Bisphenol A, Bisphenol F and Bisphenol S

Biofilm development as a factor driving the degradation of plasticised marine microplastics

Biodegradation of microplastics facilitated by natural marine biofouling is a promising approach for ocean bioremediation. However, implementation requires a comprehensive understanding of how interactions between the marine microbiome and dominant microplastic debris types (e.g., polymer and additive combinations) can influence biofilm development and drive biodegradation. To investigate this, polystyrene (PS) and polyvinyl chloride (PVC) microplastics (< 200 µm in diameter) were prepared either without any additives (i.e., virgin) or containing 15 wt% of the plasticisers diethylhexyl phthalate (DEHP) or bisphenol A (BPA). Each polymer-plasticiser microplastic combination was exposed to environmentally relevant conditions in a simulated seawater mesocosm representative of tropical reef waters over a 21-day period to allow for natural biofilm development. Following this, microplastic degradation and the colonising bacterial biofilm was assessed as a function of time, polymer and plasticiser type using infrared, thermal, gel permeation and surface characterisation techniques, as well as 16S ribosomal RNA bacterial gene sequencing, respectively. Together, these analyses revealed time-, polymer- and plasticiser-dependent degradation, particularly of the PS-BPA microplastics. Degradation of the PS-BPA microplastics also coincided with changes in bacterial community composition and an increased total relative abundance of putative biodegradative bacteria. These findings indicate that the metabolic potential and biodegradative capability of the colonising marine biofilm can be significantly impacted by the chemical properties of the microplastic substrate, even within short timeframes.

Microplastic effects on carbon cycling in terrestrial soil ecosystems: Storage, formation, mineralization, and microbial mechanisms

Soil is the largest environmental reservoir of microplastics (MPs) on the earth. Incremental accumulation of MPs in the soil can cause significant changes in soil physicochemical and microbial traits, which may in turn interfere with soil biogeochemical processes such as carbon cycling. With published research regarding MPs impacts on soil carbon cycling growing rapidly, a systematic review summarizing the current knowledge and highlighting future research needs is warranted. As carbon-rich polymers, MPs can contribute to soil organic carbon (SOC) storage via degradation and leaching. MPs can also affect the humification of dissolved organic matters (DOM), consequently influencing the stability of SOC. Exposure to MPs can cause substantial impacts on the growth performance, litter decomposition, and root secretion of terrestrial plants as well as soil microbial carbon turnover, inducing changes in the formation of SOC. The presence of MPs has contrasting effects on the emissions of both CO2 and CH4 from the soil. The diverse effects of MPs on soil carbon metabolism could be partly attributed to the varying changes in soil microbial community structure, functional gene expression, and enzyme activity under MPs exposure. Further research is still highly needed to clarify the pathways of MPs impacts on soil carbon cycling and the driving biological and physicochemical factors behind these processes.

The biochemical mechanisms of plastic biodegradation

Since the invention of the first synthetic plastic, an estimated 12 billion metric tons of plastics have been manufactured, 70% of which was produced in the last 20 years. Plastic waste is placing new selective pressures on humans and the organisms we depend on, yet it also places new pressures on microorganisms as they compete to exploit this new and growing source of carbon. The limited efficacy of traditional recycling methods on plastic waste, which can leach into the environment at low purity and concentration, indicates the utility of this evolving metabolic activity. This review will categorize and discuss the probable metabolic routes for each industrially relevant plastic, rank the most effective biodegraders for each plastic by harmonizing and reinterpreting prior literature, and explain the experimental techniques most often used in plastic biodegradation research, thus providing a comprehensive resource for researchers investigating and engineering plastic biodegradation.

Microbiological indicators of the biofilms microparticles of quartz sand and polypropylene after short-term exposure in soil

The purpose of this study was to investigate dynamics of biofilm biomass on microparticles of natural material quartz sand and the artificial material polypropylene (plastisphere) as well as change in biofilm-forming microorganisms' number under a short-term in situ field study. In this study microparticles of polypropylene and quartz sand ranging in size from 3 to 5 mm were used. The total microbial count and the number of sulfate-reducing bacteria in the biofilm (by traditional culture-based microbiological methods) and the biofilm biomass (by the method with the crystal violet) were investigated. According to the determined microbiological indicators, over time (90 days) on the polypropylene it was observed decreasing of both the number of studied groups of microorganisms and the formation of a microbial biofilm, compared to the quartz sand. Determination of microbiological indicators of the materials surface allows understanding the aspects of their preservation/removal from the environment and requires additional research.

Exploring BPA alternatives - Environmental levels and toxicity review

Bisphenol A alternatives are manufactured as potentially less harmful substitutes of bisphenol A (BPA) that offer similar functionality. These alternatives are already in the market, entering the environment and thus raising ecological concerns. However, it can be expected that levels of BPA alternatives will dominate in the future, they are limited information on their environmental safety. The EU PARC project highlights BPA alternatives as priority chemicals and consolidates information on BPA alternatives, with a focus on environmental relevance and on the identification of the research gaps. The review highlighted aspects and future perspectives. In brief, an extension of environmental monitoring is crucial, extending it to cover BPA alternatives to track their levels and facilitate the timely implementation of mitigation measures. The biological activity has been studied for BPA alternatives, but in a non-systematic way and prioritized a limited number of chemicals. For several BPA alternatives, the data has already provided substantial evidence regarding their potential harm to the environment. We stress the importance of conducting more comprehensive assessments that go beyond the traditional reproductive studies and focus on overlooked relevant endpoints. Future research should also consider mixture effects, realistic environmental concentrations, and the long-term consequences on biota and ecosystems.

Evaluation of the Effectiveness of Innovative Sorbents in Restoring Enzymatic Activity of Soil Contaminated with Bisphenol A (BPA)

As part of the multifaceted strategies developed to shape the common environmental policy, considerable attention is now being paid to assessing the degree of environmental degradation in soil under xenobiotic pressure. Bisphenol A (BPA) has only been marginally investigated in this ecosystem context. Therefore, research was carried out to determine the biochemical properties of soils contaminated with BPA at two levels of contamination: 500 mg and 1000 mg BPA kg-1 d.m. of soil. Reliable biochemical indicators of soil changes, whose activity was determined in the pot experiment conducted, were used: dehydrogenases, catalase, urease, acid phosphatase, alkaline phosphatase, arylsulfatase, and β-glucosidase. Using the definition of soil health as the ability to promote plant growth, the influence of BPA on the growth and development of Zea mays, a plant used for energy production, was also tested. As well as the biomass of aerial parts and roots, the leaf greenness index (SPAD) of Zea mays was also assessed. A key aspect of the research was to identify those of the six remediating substances-molecular sieve, zeolite, sepiolite, starch, grass compost, and fermented bark-whose use could become common practice in both environmental protection and agriculture. Exposure to BPA revealed the highest sensitivity of dehydrogenases, urease, and acid phosphatase and the lowest sensitivity of alkaline phosphatase and catalase to this phenolic compound. The enzyme response generated a reduction in the biochemical fertility index (BA21) of 64% (500 mg BPA) and 70% (1000 mg BPA kg-1 d.m. of soil). The toxicity of BPA led to a drastic reduction in root biomass and consequently in the aerial parts of Zea mays. Compost and molecular sieve proved to be the most effective in mitigating the negative effect of the xenobiotic on the parameters discussed. The results obtained are the first research step in the search for further substances with bioremediation potential against both soil and plants under BPA pressure.

Bio-organic fertilizer facilitated phytoremediation of heavy metal(loid)s-contaminated saline soil by mediating the plant-soil-rhizomicrobiota interactions

Bio-organic fertilizer (BOF) was effective to promote the phytoremediation efficiency of heavy metal(loid)s-contaminated saline soil (HCSS) by improving rhizosphere soil properties, especially microbiome. However, there existed unclear impacts of BOF on plant metabolome and plant-driven manipulation on rhizosphere soil microbiota in HCSS, which were pivotal contributors to stress defense of plants trapped in adverse conditions. Here, a pot experiment was conducted to explore the mechanisms of BOF in improving alfalfa (Medicago sativa)-performing phytoremediation of HCSS. BOF application significantly increased the biomass (150.87-401.58 %) to support the augments of accumulation regarding heavy metal(loid)s (87.50 %-410.54 %) and salts (38.27 %-271.04 %) in alfalfa. BOF promoted nutrients and aggregates stability but declined pH of rhizosphere soil, accompanied by the boosts of rhizomicrobiota including increased activity, reshaped community structure, enriched plant growth promoting rhizobacteria (Blastococcus, Modestobacter, Actinophytocola, Bacillus, and Streptomyces), strengthened mycorrhizal symbiosis (Leohumicola, Funneliformis, and unclassified_f_Ceratobasidiaceae), optimized co-occurrence networks, and beneficial shift of keystones. The conjoint analysis of plant metabolome and physiological indices confirmed that BOF reprogrammed the metabolic processes (synthesis, catabolism, and long-distance transport of amino acid, lipid, carbohydrate, phytohormone, stress-resistant secondary metabolites, etc) and physiological functions (energy supply, photosynthesis, plant immunity, nutrients assimilation, etc) that are associated intimately. The consortium of root metabolome, soil metabolome, and soil microbiome revealed that BOF facilitated the exudation of metabolites correlated with rhizomicrobiota (structure, biomarker, and keystone) and rhizosphere oxidative status, e.g., fatty acyls, phenols, coumarins, phenylpropanoids, highlighting the plant-driven regulation on rhizosphere soil microbes and environment. By compiling various results and omics data, it was concluded that BOF favored the adaptation and phytoremediation efficiency of alfalfa by mediating the plant-soil-rhizomicrobiota interactions. The results would deepen understanding of the mechanisms by which BOF improved phytoremediation of HCSS, and provide theoretical guidance to soil amelioration and BOF application.

Removal of organic and inorganic contaminants from the air, soil, and water by algae

Rapid increases in human populations and development has led to a significant exploitation of natural resources around the world. On the other hand, humans have come to terms with the consequences of their past mistakes and started to address current and future resource utilization challenges. Today's primary challenge is figuring out and implementing eco-friendly, inexpensive, and innovative solutions for conservation issues such as environmental pollution, carbon neutrality, and manufacturing effluent/wastewater treatment, along with xenobiotic contamination of the natural ecosystem. One of the most promising approaches to reduce the environmental contamination load is the utilization of algae for bioremediation. Owing to their significant biosorption capacity to deactivate hazardous chemicals, macro-/microalgae are among the primary microorganisms that can be utilized for phytoremediation as a safe method for curtailing environmental pollution. In recent years, the use of algae to overcome environmental problems has advanced technologically, such as through synthetic biology and high-throughput phenomics, which is increasing the likelihood of attaining sustainability. As the research progresses, there is a promise for a greener future and the preservation of healthy ecosystems by using algae. They might act as a valuable tool in creating new products.

Bisphenols-A Threat to the Natural Environment

Negative public sentiment built up around bisphenol A (BPA) follows growing awareness of the frequency of this chemical compound in the environment. The increase in air, water, and soil contamination by BPA has also generated the need to replace it with less toxic analogs, such as Bisphenol F (BPF) and Bisphenol S (BPS). However, due to the structural similarity of BPF and BPS to BPA, questions arise about the safety of their usage. The toxicity of BPA, BPF, and BPS towards humans and animals has been fairly well understood. The biodegradability potential of microorganisms towards each of these bisphenols is also widely recognized. However, the scale of their inhibitory pressure on soil microbiomes and soil enzyme activity has not been estimated. These parameters are extremely important in determining soil health, which in turn also influences plant growth and development. Therefore, in this manuscript, knowledge has been expanded and systematized regarding the differences in toxicity between BPA and its two analogs. In the context of the synthetic characterization of the effects of bisphenol permeation into the environment, the toxic impact of BPA, BPF, and BPS on the microbiological and biochemical parameters of soils was traced. The response of cultivated plants to their influence was also analyzed.

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.

Sensitivity of Zea mays and Soil Microorganisms to the Toxic Effect of Chromium (VI)

Chromium is used in many settings, and hence, it can easily enter the natural environment. It exists in several oxidation states. In soil, depending on its oxidation-reduction potential, it can occur in bivalent, trivalent or hexavalent forms. Hexavalent chromium compounds are cancerogenic to humans. The aim of this study was to determine the effect of Cr(VI) on the structure of bacteria and fungi in soil, to find out how this effect is modified by humic acids and to determine the response of Zea mays to this form of chromium. A pot experiment was conducted to answer the above questions. Zea mays was sown in natural soil and soil polluted with Cr(VI) in an amount of 60 mg kg-1 d.m. Both soils were treated with humic acids in the form of HumiAgra preparation. The ecophysiological and genetic diversity of bacteria and fungi was assayed in soil under maize (not sown with Zea mays). In addition, the following were determined: yield of maize, greenness index, index of tolerance to chromium, translocation index and accumulation of chromium in the plant. It has been determined that Cr(VI) significantly distorts the growth and development of Zea mays, while humic acids completely neutralize its toxic effect on the plant. This element had an adverse effect on the development of bacteria of the genera Cellulosimicrobium, Kaistobacter, Rhodanobacter, Rhodoplanes and Nocardioides and fungi of the genera Chaetomium and Humicola. Soil contamination with Cr(VI) significantly diminished the genetic diversity and richness of bacteria and the ecophysiological diversity of fungi. The negative impact of Cr(VI) on the diversity of bacteria and fungi was mollified by Zea mays and the application of humic acids.

Bisphenol S degradation in soil and the dynamics of microbial community associated with degradation

Bisphenol S (BPS) has been widely applied as a replacement for BPA in industrial application, leading to the frequent detection in the environment. However, its impact on soil microbial communities has not been well reported. Here, effects of BPS exposure on soil microbial communities in the presence of polystyrene (PS) microplastics were revealed. Rapid degradation of BPS occurred with a degradation rate of up to 98.9 ± 0.001 % at 32 d. The presence of BPS reduced the diversity of soil microbial communities, and changed community structures. After BPS treatment, Proteobacteria, and its members Methylobacillus, Rhodobacteraceae and Mesorhizobium became dominant, and were considered as potential biomarkers indicating BPS contamination. Co-occurrence network analysis revealed the increased relationships of certain groups of microbes after BPS treatment. The resultant low stability and resilience towards environment disturbance of microbial community networks implied the biotoxicity of BPS towards soil ecosystems. The degradation and biotoxicity of BPS (p > 0.05) in soil was not affected by the presence of PS. Our findings showed that exposure to BPS could reshape soil microbial communities and impair the robustness of microbial co-occurrence networks.

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.

Accumulation of nylon microplastics and polybrominated diphenyl ethers and effects on gut microbial community of Chironomus sancticaroli

Microplastics (MP) are emerging contaminants with the capacity to bind and transport hydrophobic organic compounds of environmental concern, such as polybrominated diphenyl ethers (PBDEs). The aim of this study was to investigate the ingestion of nylon (polyamide) MP alone and when associated with PBDEs and their effects on Chironomus sancticaroli larvae survival and microbiome structure. Survival, PBDE uptake and microbial community composition were measured in fourth instar larvae exposed for 96 h to BDEs- 47, 99, 100 and 153 in the presence and absence of 1% w/w MP in sediment. Microbiome community structures were determined through high throughput sequencing of 16S small subunit ribosomal RNA gene (16S rRNA). Initial experiments showed that larvae ingested MP faster at 0.5% w/w MP, while depuration was more efficient at 1% w/w MP, although retention of MP was seen even after 168 h depuration. No mortality was observed as a result of PBDEs and MP exposure. MP had a negative effect on PBDE concentration within larvae (η² = 0.94) and a negative effect on sediment concentrations (η² = 0.48). In all samples, microbial communities were dominated by Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Gammaproteobacteria. Bacterial alpha diversity was not significantly affected by PBDEs or MP exposure. However, the abundance of discrete bacterial taxa was more sensitive to MP (X² = 45.81, p = 0.02), and PBDE exposure. Our results highlight that C. sancticaroli showed no acute response to MPs and PBDEs, but that MPs influenced bacterial microbiome structure even after only short-term acute exposure.

Repeated introduction of micropollutants enhances microbial succession despite stable degradation patterns

The increasing-volume release of micropollutants into natural surface waters has raised great concern due to their environmental accumulation. Persisting micropollutants can impact multiple generations of organisms, but their microbially-mediated degradation and their influence on community assembly remain understudied. Here, freshwater microbes were treated with several common micropollutants, alone or in combination, and then transferred every 5 days to fresh medium containing the same micropollutants to mimic the repeated exposure of microbes. Metabarcoding of 16S rRNA gene makers was chosen to study the succession of bacterial assemblages following micropollutant exposure. The removal rates of micropollutants were then measured to assess degradation capacity of the associated communities. The degradation of micropollutants did not accelerate over time but altered the microbial community composition. Community assembly was dominated by stochastic processes during early exposure, via random community changes and emergence of seedbanks, and deterministic processes later in the exposure, via advanced community succession. Early exposure stages were characterized by the presence of sensitive microorganisms such as Actinobacteria and Planctomycetes, which were then replaced by more tolerant bacteria such as Bacteroidetes and Gammaproteobacteria. Our findings have important implication for ecological feedback between microbe-micropollutants under anthropogenic climate change scenarios.

Effect of Separate and Combined Toxicity of Bisphenol A and Zinc on the Soil Microbiome

The research objective was established by taking into account common sources of soil contamination with bisphenol A (B) and zinc (Zn2+), as well as the scarcity of data on the effect of metabolic pathways involved in the degradation of organic compounds on the complexation of zinc in soil. Therefore, the aim of this study was to determine the spectrum of soil homeostasis disorders arising under the pressure of both the separate and combined toxicity of bisphenol A and Zn2+. With a broad pool of indicators, such as indices of the effect of xenobiotics (IFX), humic acid (IFH), plants (IFP), colony development (CD), ecophysiological diversity (EP), the Shannon-Weaver and the Simpson indices, as well as the index of soil biological fertility (BA21), the extent of disturbances was verified on the basis of enzymatic activity, microbiological activity, and structural diversity of the soil microbiome. A holistic character of the study was achieved, having determined the indicators of tolerance (IT) of Sorghum Moench (S) and Panicum virgatum (P), the ratio of the mass of their aerial parts to roots (PR), and the SPAD leaf greenness index. Bisphenol A not only failed to perform a complexing role towards Zn2+, but in combination with this heavy metal, had a particularly negative effect on the soil microbiome and enzymatic activity. The NGS analysis distinguished certain unique genera of bacteria in all objects, representing the phyla Actinobacteriota and Proteobacteria, as well as fungi classified as members of the phyla Ascomycota and Basidiomycota. Sorghum Moench (S) proved to be more sensitive to the xenobiotics than Panicum virgatum (P).

Bisphenol A-A Dangerous Pollutant Distorting the Biological Properties of Soil

Bisphenol A (BPA), with its wide array of products and applications, is currently one of the most commonly produced chemicals in the world. A narrow pool of data on BPA–microorganism–plant interaction mechanisms has stimulated the following research, the aim of which has been to determine the response of the soil microbiome and crop plants, as well as the activity of soil enzymes exposed to BPA pressure. A range of disturbances was assessed, based on the activity of seven soil enzymes, an abundance of five groups of microorganisms, and the structural diversity of the soil microbiome. The condition of the soil was verified by determining the values of the indices: colony development (CD), ecophysiological diversity (EP), the Shannon–Weaver index, and the Simpson index, tolerance of soil enzymes, microorganisms and plants (TI_BPA), biochemical soil fertility (BA₂₁), the ratio of the mass of aerial parts to the mass of plant roots (PR), and the leaf greenness index: Soil and Plant Analysis Development (SPAD). The data brought into sharp focus the adverse effects of BPA on the abundance and ecophysiological diversity of fungi. A change in the structural composition of bacteria was noted. Bisphenol A had a more beneficial effect on the Proteobacteria than on bacteria from the phyla Actinobacteria or Bacteroidetes. The microbiome of the soil exposed to BPA was numerously represented by bacteria from the genus Sphingomonas. In this object pool, the highest fungal OTU richness was achieved by the genus Penicillium, a representative of the phylum Ascomycota. A dose of 1000 mg BPA kg⁻¹ d.m. of soil depressed the activity of dehydrogenases, urease, acid phosphatase and β-glucosidase, while increasing that of alkaline phosphatase and arylsulfatase. Spring oilseed rape and maize responded significantly negatively to the soil contamination with BPA.

Classroom microbiome, functional pathways and sick-building syndrome (SBS) in urban and rural schools - Potential roles of indoor microbial amino acids and vitamin metabolites

Sick building symptoms (SBS) are defined as non-specific symptoms related to indoor exposures, including mucosal symptoms in eye, nose, throat, and skin, and general symptoms as headache and tiredness. Indoor microbial composition is associated with SBS symptoms, but the impact of microbial functional genes and potential metabolic products has not been characterized. We conducted a shotgun microbial metagenomic sequencing for vacuum dust collected in urban and rural schools in Shanxi province, China. SBS symptoms in students were surveyed, and microbial taxa and functional pathways related to the symptoms were identified using a multi-level linear regression model. SBS symptoms were common in students, and the prevalence of ocular and throat symptoms, headache, and tiredness was higher in urban than in rural areas (p < 0.05). A significant higher microbial α-diversity was found in rural areas than in urban areas (Chao1, p = 0.001; ACE, p = 0.002). Also, significant variation in microbial taxonomic and functional composition (β-diversity) was observed between urban and rural areas (p < 0.005). Five potential risk Actinobacteria species were associated with SBS symptoms (p < 0.01); students in the classrooms with a higher abundance of an unclassified Geodermatophilaceae, Geodermatophilus, Fridmanniella luteola, Microlunatus phosphovorus and Mycetocola reported more nasal and throat symptoms and tiredness. Students with a higher abundance of an unclassified flavobacteriaceae reported fewer throat symptoms and tiredness. The abundance of microbial metabolic pathways related to the synthesis of B vitamins (biotin and folate), gamma-aminobutyric acid (GABA), short-chain fatty acids (SCFAs), and peptidoglycan and were protectively (negatively) associated with SBS symptoms (FDR < 0.05). The result is consistent with human microbiota studies, which reported that these microbial products are extensively involved in immunological processes and anti-inflammatory effects. This is the first study to report the functional potential of the indoor microbiome and the occurrence of SBS, providing new insights into the potential etiologic mechanisms in chronic inflammatory diseases.

Perna canaliculus as an Ecological Material in the Removal of o-Cresol Pollutants from Soil

Soil contamination with cresol is a problem of the 21st century and poses a threat to soil microorganisms, humans, animals, and plants. The lack of precise data on the potential toxicity of o-cresol in soil microbiome and biochemical activity, as well as the search for effective remediation methods, inspired the aim of this study. Soil is subjected to four levels of contamination with o-cresol: 0, 0.1, 1, 10, and 50 mg o-cresol kg-1 dry matter (DM) of soil and the following are determined: the count of eight groups of microorganisms, colony development index (CD) and ecophysiological diversity index (EP) for organotrophic bacteria, actinobacteria and fungi, and the bacterial genetic diversity. Moreover, the responses of seven soil enzymes are investigated. Perna canaliculus is a recognized biosorbent of organic pollutants. Therefore, microbial biostimulation with Perna canaliculus shells is used to eliminate the negative effect of the phenolic compound on the soil microbiome. Fungi appears to be the microorganisms most sensitive to o-cresol, while Pseudomonas sp. is the least sensitive. In o-cresol-contaminated soils, the microbiome is represented mainly by the bacteria of the Proteobacteria and Firmicutes phyla. Acid phosphatase, alkaline phosphatase and urease can be regarded as sensitive indicators of soil disturbance. Perna canaliculus shells prove to be an effective biostimulator of soil under pressure with o-cresol.

Mesosulfuron-methyl influenced biodegradability potential and N transformation of soil

The wide application of mesosulfuron-methyl (MS) in soil may affect soil microbial community, yet the information is limited. In this work, two distinct soil types from Anyang (AY) and Nanjing (NJ) were spiked with MS (0, 0.006, 0.06, or 0.6 mg kg^-1) and incubated for 90 days. MS decreased bacterial and fungal (except the last sampling) abundance and altered their diversity and community. Five biomarkers of bacterial species may help MS degradation and more increased xenobiotics biodegradation pathways were also observed in 0.6 mg kg^-1 treatment in AY soil. A co-occurrence network revealed the biomarkers grouped in one module in all AY soils, suggesting these biomarkers act in concert to degrade MS. MS impacted soil N transformation with increasing N₂-fixing bacteria in both soils and ammonia-oxidising bacteria (AOB) in NJ and decreasing ammonia-oxidizing archaea (AOA) in AY. The contents of NO₃^--N and NH₄⁺-N were increased by MS. Structural equation models revealed that the abundance of bacteria and fungi was responsible for the NO₃^--N and NH₄⁺-N contents. In conclusion, this work aids safety assessments and degradation-related research of MS in soil.

Biodegradation of bisphenol-A polycarbonate plastic by Pseudoxanthomonas sp. strain NyZ600

Bisphenol-A polycarbonate (PC) is a widely used engineering thermoplastic and its release has caused damage to the ecosystem. Microbial degradation of plastic represents a sustainable approach for PC reduction. In this study, a bacterial strain designated Pseudoxanthomonas sp. strain NyZ600 capable of degrading PC was isolated from activated sludge by using diphenyl carbonate as a surrogate substrate. Within a 30-day period of incubating with strain NyZ600, PC films were analyzed with atomic force microscopy, scanning electron microscope, water contact angle, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, differential scan calorimeter and thermogravimetric analysis technique. The analyses results indicated that the treated PC films were bio-deteriorated and formed some "corrosion pits" on the PC film surface. In addition, strain NyZ600 performed broad depolymerization of PC indicated by the reduction of Mn from 23.55 to 16.75 kDa and Mw from 45.67 to 31.97 kDa and two degradation products bisphenol A and 4-cumylphenol (the two monomers of PC) were also found, which established that PC were biodegraded by strain NyZ600. Combing all above results, it is clear that the strain NyZ600 can degrade PC which provides a unique example for bacterial degradation of PC and a feasibility for the removal of PC waste.

Influence of bisphenol A occurrence in wastewaters on biomass characteristics and activated sludge process performance

In this work, the influence of bisphenol A (BPA) on biological wastewater treatment was studied. For it, two sequencing batch reactors (SBRs) were operated for three months. Both SBRs were fed with synthetic wastewater (SW), adding 1 mg·L^-1 of BPA into the feed of reactor SBR-BPA, while the other one operated without BPA as a control reactor (SBR-B). In addition, batch experiments were performed with adapted and non-adapted activated sludge, simulating the reaction step of SBR-BPA, to determine the pathways for BPA removal. Results of batch experiments showed that adsorption and biodegradation were the only significant BPA removal routes. BPA removal by biodegradation was more efficient when adapted biomass was used in the tests (32.2% and 8.2% with adapted and non-adapted biomass, respectively), while BPA adsorption removal route was similar in both types of activated sludge (around 40%). Regarding the SBRs experiments, after 16 days no BPA concentration was detected in SBR-BPA effluent. In the adaptation process, SBR-BPA biomass was more sensitive to low temperatures resulting in higher effluent turbidity, COD and soluble microbial products concentrations than in SBR-B. However, once temperature increased, adapted biomass from SBR-BPA presented higher activity than SBR-B biomass, showing higher values of sludge production, microbial hydrolytic enzymatic activities and specific dynamic respiration rate. The bacterial community study revealed the increase of abundance of Proteobacteria (especially Thiothrix species) and Actinobacteria (especially Nocardioides species) phyla at the expense of Bacteroidetes and Chloroflexi phyla in SBR-BPA during its operation.

Microbiological Study in Petrol-Spiked Soil

The pollution of arable lands and water with petroleum-derived products is still a valid problem, mainly due the extensive works aimed to improve their production technology to reduce fuel consumption and protect engines. An example of the upgraded fuels is the BP 98 unleaded petrol with Active technology. A pot experiment was carried out in which Eutric Cambisol soil was polluted with petrol to determine its effect on the microbiological and biochemical properties of this soil. Analyses were carried out to determine soil microbiome composition-with the incubation and metagenomic methods, the activity of seven enzymes, and cocksfoot effect on hydrocarbon degradation. The following indices were determined: colony development index (CD); ecophysiological diversity index (EP); index of cocksfoot effect on soil microorganisms and enzymes (IFG); index of petrol effect on soil microorganisms and enzymes (IFP); index of the resistance of microorganisms, enzymes, and cocksfoot to soil pollution with petrol (RS); Shannon-Weaver's index of bacterial taxa diversity (H); and Shannon-Weaver's index of hydrocarbon degradation (IDH). The soil pollution with petrol was found to increase population numbers of bacteria and fungi, and Protebacteria phylum abundance as well as to decrease the abundance of Actinobacteria and Acidobacteria phyla. The cultivation of cocksfoot on the petrol-polluted soil had an especially beneficial effect mainly on the bacteria belonging to the Ramlibacter, Pseudoxanthomonas, Mycoplana, and Sphingobium genera. The least susceptible to the soil pollution with petrol and cocksfoot cultivation were the bacteria of the following genera: Kaistobacter, Rhodoplanes, Bacillus, Streptomyces, Paenibacillus, Phenylobacterium, and Terracoccus. Cocksfoot proved effective in the phytoremediation of petrol-polluted soil, as it accelerated hydrocarbon degradation and increased the genetic diversity of bacteria. It additionally enhanced the activities of soil enzymes.

Fabrication and Adsorption Optimization of Novel Magnetic Core-shell Chitosan/Graphene Oxide/β-cyclodextrin Composite Materials for Bisphenols in Aqueous Solutions

A novel magnetic composite material, Fe3O4@SiO2/chitosan/graphene oxide/β-cyclodextrin (MCGC), was prepared by multi-step methods. Various methods were used to systematically characterize the morphology, composition, structure, and magnetic properties of MCGC. The results obtained show that the composite material has good morphology and crystal structure and can be separated quickly by an external magnetic field. The operation is relatively easy, and the raw materials used to prepare this material are economical, easy to obtain, and environmentally friendly. The performance and adsorption mechanism for using this material as an adsorbent to remove bisphenol A (BPA) and bisphenol F (BPF) from water were studied. The adsorption parameters were optimized. Under optimal conditions, MCGC was found to remove more than 90% of BPA and BPF in a mixed solution (20 mg/L, 50 mL); the adsorption process for BPA and BPF on MCGC was found to follow a Redlich-Peterson isotherm model and Pseudo-second-order kinetic model. The adsorption mechanism for MCGC may involve a combination of various forces. Recycling experiments showed that after five uses, MCGC retained a more than 80% removal effect for BPA and BPF, and through real sample verification, MCGC can be used for wastewater treatment. Therefore, MCGC is economical, environmentally friendly, and easy to separate and collect, and has suitable stability and broad application prospects.