Pub Date : 2025-11-08DOI: 10.1016/j.ibiod.2025.106231
Guiling Zheng , Xiaoxia Hao , Binyan Hong , Dongmei Jiang , Hongxi Qian , Lin Bai
Against the backdrop of increasing concern regarding nitrogen (N) loss and greenhouse gas (GHG) emissions from livestock operations, this study evaluated the efficacy of an integrated thermophilic-vermicomposting system for the treatment of pig manure. Compared with conventional thermophilic composting (AC) and single vermicomposting (V), the combined thermophilic–vermicomposting (CV) approach markedly improved compost quality. Specifically, total nitrogen (TN), germination index (GI), and humification index (HIX) increased by 27 % and 7 %, 44 % and 26 %, and 51 % and 17 %, respectively. It also promoted the abundance of functional genes involved in nitrification (amoA, amoB), denitrification (nirS, etc.), and carbon cycling (pccA, etc.). Furthermore, the CV process significantly increased ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) contents by 58.96 % and 1476 %, respectively, compared with AC, while effectively reducing carbon dioxide (CO2), methane (CH4), and ammonia (NH3) emissions. These findings demonstrate that integrated thermophilic-vermicomposting is a promising strategy for sustainable livestock waste management, simultaneously improving compost maturity and reducing environmental impacts.
{"title":"Thermophilic-vermicomposting enhances nitrogen retention and reduces greenhouse gas emissions via microbial gene regulation","authors":"Guiling Zheng , Xiaoxia Hao , Binyan Hong , Dongmei Jiang , Hongxi Qian , Lin Bai","doi":"10.1016/j.ibiod.2025.106231","DOIUrl":"10.1016/j.ibiod.2025.106231","url":null,"abstract":"<div><div>Against the backdrop of increasing concern regarding nitrogen (N) loss and greenhouse gas (GHG) emissions from livestock operations, this study evaluated the efficacy of an integrated thermophilic-vermicomposting system for the treatment of pig manure. Compared with conventional thermophilic composting (AC) and single vermicomposting (V), the combined thermophilic–vermicomposting (CV) approach markedly improved compost quality. Specifically, total nitrogen (TN), germination index (GI), and humification index (HIX) increased by 27 % and 7 %, 44 % and 26 %, and 51 % and 17 %, respectively. It also promoted the abundance of functional genes involved in nitrification (<em>amo</em>A, <em>amo</em>B), denitrification (<em>nir</em>S, etc.), and carbon cycling (<em>pcc</em>A, etc.). Furthermore, the CV process significantly increased ammonium nitrogen (NH<sub>4</sub><sup>+</sup>-N) and nitrate nitrogen (NO<sub>3</sub><sup>−</sup>-N) contents by 58.96 % and 1476 %, respectively, compared with AC, while effectively reducing carbon dioxide (CO<sub>2</sub>), methane (CH<sub>4</sub>), and ammonia (NH<sub>3</sub>) emissions. These findings demonstrate that integrated thermophilic-vermicomposting is a promising strategy for sustainable livestock waste management, simultaneously improving compost maturity and reducing environmental impacts.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106231"},"PeriodicalIF":4.1,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145516706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-21DOI: 10.1016/j.ibiod.2025.106230
Reihaneh Moridshahi, Zahra Etemadifar
Cephalexin (CPX), a β-lactam antibiotic, is considered an emerging pollutant due to its incomplete removal in conventional treatment systems and its contribution to antimicrobial resistance. This study investigated a novel indigenous strain, Bacillus wiedmannii RM5, isolated from municipal activated sludge, which efficiently degraded CPX. Under optimized conditions (pH 6.5, 50 mg/L initial CPX, 60 h incubation), strain RM5 achieved 95.5 % CPX removal, as determined using OFAT and Box–Behnken design with RSM. The ddition of glucose significantly enhanced co-metabolism, leading to complete degradation within 36 h. The strain exhibited stable performance across a pH range of 6–9, temperatures of 30–45 °C, and CPX concentrations up to 400 mg/L, indicating its potential for application under real-world environmental conditions. LC–MS/MS analysis identified 13 intermediates, suggesting two concurrent enzymatic degradation pathways. These pathways involve β-lactamase-mediated ring cleavage, hydrolysis, and oxidation catalyzed by hydrolases and oxidases, leading to non-toxic mineral end products. MIC and MTT bioassays showed that, unlike untreated CPX, its degraded metabolites exhibited no antibacterial or cytotoxic activity. Bacillus wiedmannii RM5 effectively degraded CPX, amoxicillin (AMX), and ampicillin (AMP) simultaneously across diverse environmental conditions, showcasing its broad-spectrum biodegradation potential. These findings highlight Bacillus wiedmannii RM5 as a promising, safe, and effective bioremediation agent for removing β-lactam antibiotics from wastewater, offering a practical strategy to reduce pharmaceutical pollution and antibiotic resistance.
{"title":"Biodegradation and detoxification of cephalexin by Bacillus wiedmannii RM5: Pathways, optimization, and safety assessment","authors":"Reihaneh Moridshahi, Zahra Etemadifar","doi":"10.1016/j.ibiod.2025.106230","DOIUrl":"10.1016/j.ibiod.2025.106230","url":null,"abstract":"<div><div>Cephalexin (CPX), a β-lactam antibiotic, is considered an emerging pollutant due to its incomplete removal in conventional treatment systems and its contribution to antimicrobial resistance. This study investigated a novel indigenous strain, <em>Bacillus wiedmannii RM5</em>, isolated from municipal activated sludge, which efficiently degraded CPX. Under optimized conditions (pH 6.5, 50 mg/L initial CPX, 60 h incubation), strain RM5 achieved 95.5 % CPX removal, as determined using OFAT and Box–Behnken design with RSM. The ddition of glucose significantly enhanced co-metabolism, leading to complete degradation within 36 h. The strain exhibited stable performance across a pH range of 6–9, temperatures of 30–45 °C, and CPX concentrations up to 400 mg/L, indicating its potential for application under real-world environmental conditions. LC–MS/MS analysis <strong>identified</strong> 13 intermediates, <strong>suggesting</strong> two concurrent enzymatic degradation pathways. These pathways involve β-lactamase-mediated ring cleavage, hydrolysis, and oxidation catalyzed by hydrolases and oxidases, leading to non-toxic mineral end products. MIC and MTT bioassays showed that, unlike untreated CPX, its degraded metabolites exhibited no antibacterial or cytotoxic activity. <em>Bacillus wiedmannii RM5</em> effectively degraded CPX, amoxicillin (AMX), and ampicillin (AMP) simultaneously across diverse environmental conditions, showcasing its broad-spectrum biodegradation <strong>potential</strong>. These findings highlight <em>Bacillus wiedmannii RM5</em> as a promising, safe, and effective bioremediation agent for removing β-lactam antibiotics from wastewater, offering a <strong>practical</strong> strategy to reduce pharmaceutical pollution and antibiotic resistance.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106230"},"PeriodicalIF":4.1,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145359648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-17DOI: 10.1016/j.ibiod.2025.106229
Hanqing Pan , Jia Shi , Dan Xu , Jingwei Wang , Qiao Ma
p-Chloro-m-xylenol (PCMX), a halogenated phenolic antimicrobial agent, has gained global prominence in disinfectants and personal care products. This review synthesizes current knowledge on PCMX's environmental occurrence, ecological impacts, and microbial transformation mechanisms. Environmental monitoring reveals pervasive contamination (ng/L to mg/L) across wastewater systems and surface waters, with seasonal and regional variability linked to consumption patterns and treatment inefficiencies. Ecotoxicological assessments demonstrate acute toxicity to aquatic organisms and chronic effects, such as developmental abnormalities, endocrine disruption, and neurobehavioral impairments. Emerging evidence highlights PCMX's role in promoting antibiotic resistance gene dissemination via enhanced horizontal gene transfer. Critically, microbial degradation studies identify Rhodococcus species as key degraders, employing pathways involving dechlorination to 2,6-dimethylhydroquinone or hydroxylation to 4-chloro-3,5-dimethylcatechol. Mechanistic insights reveal a flavin-dependent monooxygenase (CxyA) catalyzing initial transformation, though genetic regulation and roles of associated enzymes (e.g., CYP450) require further elucidation. This review establishes PCMX as a nonnegligible emerging contaminant, emphasizing the need for coordinated monitoring strategies, refined ecological risk assessment frameworks, and innovative bioremediation approaches to mitigate its environmental impacts.
{"title":"Environmental occurrence, ecological risks, and microbial interactions of p-chloro-m-xylenol: An emerging ubiquitous antimicrobial agent","authors":"Hanqing Pan , Jia Shi , Dan Xu , Jingwei Wang , Qiao Ma","doi":"10.1016/j.ibiod.2025.106229","DOIUrl":"10.1016/j.ibiod.2025.106229","url":null,"abstract":"<div><div><em>p</em>-Chloro-<em>m</em>-xylenol (PCMX), a halogenated phenolic antimicrobial agent, has gained global prominence in disinfectants and personal care products. This review synthesizes current knowledge on PCMX's environmental occurrence, ecological impacts, and microbial transformation mechanisms. Environmental monitoring reveals pervasive contamination (ng/L to mg/L) across wastewater systems and surface waters, with seasonal and regional variability linked to consumption patterns and treatment inefficiencies. Ecotoxicological assessments demonstrate acute toxicity to aquatic organisms and chronic effects, such as developmental abnormalities, endocrine disruption, and neurobehavioral impairments. Emerging evidence highlights PCMX's role in promoting antibiotic resistance gene dissemination via enhanced horizontal gene transfer. Critically, microbial degradation studies identify <em>Rhodococcus</em> species as key degraders, employing pathways involving dechlorination to 2,6-dimethylhydroquinone or hydroxylation to 4-chloro-3,5-dimethylcatechol. Mechanistic insights reveal a flavin-dependent monooxygenase (CxyA) catalyzing initial transformation, though genetic regulation and roles of associated enzymes (e.g., CYP450) require further elucidation. This review establishes PCMX as a nonnegligible emerging contaminant, emphasizing the need for coordinated monitoring strategies, refined ecological risk assessment frameworks, and innovative bioremediation approaches to mitigate its environmental impacts.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106229"},"PeriodicalIF":4.1,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-16DOI: 10.1016/j.ibiod.2025.106228
Jiannan Wang , Renju Liu , Sufang Zhao , Zongze Shao
Marine sediments are major sinks for microplastics, with concentrations significantly higher than in seawater. However, little is known about the biodegradation of plastic debris in oxygen-deficient sediments. In this study, we characterized the bacteria with the potential for anaerobic degradation of plastics in sediments sampled from the semi-closed Sansha Bay located in the Taiwan Strait. Using common polyhydrocarbon plastics—polyethylene (PE), polypropylene (PP), and polystyrene (PS)—as the sole carbon and energy sources, anaerobic degrading bacteria were enriched under nitrate-reducing and iron-reducing conditions. After incubation, bacterial community analysis based on 16S rRNA sequencing revealed that under iron-reducing conditions, norank_Caulobacteraceae, Ralstonia, Shewanella, and Vibrio were the most abundant core taxa, whereas Shewanella and Vibrio dominated nitrate-reducing communities across all plastic types. Co-occurrence network analysis further indicated that members of Proteobacteria and Desulfobacterota cooperatively contributed to plastic anaerobic degradation. At the genus level, Vibrio was identified as the most prominent keystone taxon alongside Marinobacter. Bacterial isolation and biodegradation assays confirmed Vibrio alginolyticus as an anaerobic degrader under nitrate-reducing conditions, capable of forming biofilms on PE, PP, and PS surfaces and inducing physicochemical deterioration. This study provides the first evidence of bacteria involved in anaerobic plastic degradation in marine environments, underscoring that this process may actively influence the fate of plastic debris and microplastics in marine sediments.
{"title":"Bacteria involved in plastic anaerobic degradation in marine sediments under nitrate and iron-reducing conditions","authors":"Jiannan Wang , Renju Liu , Sufang Zhao , Zongze Shao","doi":"10.1016/j.ibiod.2025.106228","DOIUrl":"10.1016/j.ibiod.2025.106228","url":null,"abstract":"<div><div>Marine sediments are major sinks for microplastics, with concentrations significantly higher than in seawater. However, little is known about the biodegradation of plastic debris in oxygen-deficient sediments. In this study, we characterized the bacteria with the potential for anaerobic degradation of plastics in sediments sampled from the semi-closed Sansha Bay located in the Taiwan Strait. Using common polyhydrocarbon plastics—polyethylene (PE), polypropylene (PP), and polystyrene (PS)—as the sole carbon and energy sources, anaerobic degrading bacteria were enriched under nitrate-reducing and iron-reducing conditions. After incubation, bacterial community analysis based on 16S rRNA sequencing revealed that under iron-reducing conditions, norank_<em>Caulobacteraceae</em>, <em>Ralstonia</em>, <em>Shewanella</em>, and <em>Vibrio</em> were the most abundant core taxa, whereas <em>Shewanella</em> and <em>Vibrio</em> dominated nitrate-reducing communities across all plastic types. Co-occurrence network analysis further indicated that members of <em>Proteobacteria</em> and <em>Desulfobacterota</em> cooperatively contributed to plastic anaerobic degradation. At the genus level, <em>Vibrio</em> was identified as the most prominent keystone taxon alongside <em>Marinobacter</em>. Bacterial isolation and biodegradation assays confirmed <em>Vibrio alginolyticus</em> as an anaerobic degrader under nitrate-reducing conditions, capable of forming biofilms on PE, PP, and PS surfaces and inducing physicochemical deterioration. This study provides the first evidence of bacteria involved in anaerobic plastic degradation in marine environments, underscoring that this process may actively influence the fate of plastic debris and microplastics in marine sediments.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106228"},"PeriodicalIF":4.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-16DOI: 10.1016/j.ibiod.2025.106227
Junaid Ahmad Raza, Aqsa Aslam, Sibtain Ahmed, Hina Andaleeb, Sheikh Muhammad Yahya Waseem
Microbial enzymes such as cellulases and lichenase hold great importance in industrial and biotechnological sectors. This study demonstrates the successful enhancement of cellulase and lichenase production in Bacillus subtilis through strain improvement and process optimization. By using ethyl methanesulfonate (EMS) for bacterial mutagenesis followed by comprehensive screening, a mutant strain was obtained that exhibited superior enzymatic performance compared to the wild-type strain. Subsequent optimization studies utilizing low-cost lignocellulosic substrates revealed wheat straw and barley flour as the most effective agricultural wastes for cellulase and Lichenase production under ideal fermentation conditions (pH 7.0, 35 °C, 72 h incubation). For both enzymes, optimal production was reached when cultivated with sucrose and tryptone as the primary carbon and nitrogen source. Detailed kinetic characterization of the enzymes produced by the mutant strain showed that there is an increase in enzyme substrate binding affinity as well as rate of catalysis in endoglucanase, exoglucanase, β-glucosidase, and lichenase. The mutant enzymes exhibited remarkable thermostability and pH stability, retaining nearly 80 % of their initial activity over a 4-h period. These findings provide both fundamental insights into the enhancement of enzymes through chemical mutagenesis and practical solutions for industrial enzyme production. The demonstrated approach combines strain improvement with sustainable utilization, offering a viable pathway to reduce production cost and maintain high yields. This work particularly highlights the potential of agricultural residues in biotechnological applications and establishes a framework for future strain development efforts targeting hydrolytic enzyme production.
{"title":"Waste-to-resource: Enhanced production of cellulases and lichenase from lignocellulosic biomass via mutated Bacillus subtilis","authors":"Junaid Ahmad Raza, Aqsa Aslam, Sibtain Ahmed, Hina Andaleeb, Sheikh Muhammad Yahya Waseem","doi":"10.1016/j.ibiod.2025.106227","DOIUrl":"10.1016/j.ibiod.2025.106227","url":null,"abstract":"<div><div>Microbial enzymes such as cellulases and lichenase hold great importance in industrial and biotechnological sectors. This study demonstrates the successful enhancement of cellulase and lichenase production in <em>Bacillus subtilis</em> through strain improvement and process optimization. By using ethyl methanesulfonate (EMS) for bacterial mutagenesis followed by comprehensive screening, a mutant strain was obtained that exhibited superior enzymatic performance compared to the wild-type strain. Subsequent optimization studies utilizing low-cost lignocellulosic substrates revealed wheat straw and barley flour as the most effective agricultural wastes for cellulase and Lichenase production under ideal fermentation conditions (pH 7.0, 35 °C, 72 h incubation). For both enzymes, optimal production was reached when cultivated with sucrose and tryptone as the primary carbon and nitrogen source. Detailed kinetic characterization of the enzymes produced by the mutant strain showed that there is an increase in enzyme substrate binding affinity as well as rate of catalysis in endoglucanase, exoglucanase, β-glucosidase, and lichenase. The mutant enzymes exhibited remarkable thermostability and pH stability, retaining nearly 80 % of their initial activity over a 4-h period. These findings provide both fundamental insights into the enhancement of enzymes through chemical mutagenesis and practical solutions for industrial enzyme production. The demonstrated approach combines strain improvement with sustainable utilization, offering a viable pathway to reduce production cost and maintain high yields. This work particularly highlights the potential of agricultural residues in biotechnological applications and establishes a framework for future strain development efforts targeting hydrolytic enzyme production.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106227"},"PeriodicalIF":4.1,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-12DOI: 10.1016/j.ibiod.2025.106226
Tao Wu , Yaguang Li , Jibiao Zhang , Runze Tian , Lieyu Zhang
Submerged macrophyte phyllosphere-associated biofilms serve as a critical reservoirs and potential transmission vectors for antibiotic resistance genes (ARGs), potentially exacerbating ecological risk in aquatic ecosystems. In this study, metagenomic sequencing and microbial community profilingwere employed to systematically investigate the spatiotemporal ARGs dynamics in Vallisneria natans phyllosphere-associated biofilms within an ecological purification pond. Key findings identified that multidrug resistance (MDR) genes constituted 39 % of the total detected ARGs in the phyllosphere-associated biofilms, exhibiting 11.3 % higher abundance compared to the aquatic biofilms (35 % of total detected ARGs). Principal coordinates analysis demonstrated significant segregation between the phyllosphere and adjacent water biofilm resistomes, explaining 48.76 % of the variance and indicating plant-mediated selection of resistant microorganisms via microenvironmental modification. Seasonal variation predominates over spatial in structuring microbiota and ARGs, with taxa-specific monthly shifts. Microbial community profiling identified Pseudomonas (50.8 %) and Bacteroidetes (11.35 %) as the dominant phyllosphere taxa, exhibiting significant correlations with key environmental parameters. Specifically, Pseudomonas abundance positively correlated with water temperature (R2 = 0.51, P < 0.01), while Bacteroidetes showed a temperature-independent association with the oxidation-reduction potential (R2 = 0.48, P < 0.05). Linear discriminant analysis effect size identified Diatoms (14.31 %) as a biomarker group, suggesting that photosynthesis-driven carbon exchange enhances algae-bacteria symbiosis. Finally, co-occurrence network analysis established Pseudomonas and Flavobacterium as the potential ARG hosts. These findings provide valuable insights for optimizing the design of ecological purification ponds and developing targeted ARG control protocols in aquatic ecosystems.
沉水植物叶层相关生物膜是抗生素耐药基因（ARGs）的重要宿主和潜在传播载体，可能加剧水生生态系统的生态风险。本研究采用宏基因组测序和微生物群落分析方法，系统研究了生态净化池内水蛭根层相关生物膜中ARGs的时空动态变化。主要发现发现，多药耐药（MDR）基因占层球相关生物膜中总检测到的ARGs的39%，比水生生物膜的丰度高11.3%（占总检测到的ARGs的35%）。主坐标分析表明，层球和相邻的水生物膜抗性体之间存在显著的分离，解释了48.76%的差异，表明植物通过微环境修饰介导了抗性微生物的选择。在微生物群和ARGs的结构中，季节变化占主导地位，具有特定分类群的月度变化。微生物群落分析显示，假单胞菌（50.8%）和拟杆菌门菌（11.35%）是层球的优势类群，与关键环境参数呈显著相关。其中，假单胞菌丰度与水温呈正相关（R2 = 0.51, P < 0.01），拟杆菌门菌丰度与氧化还原电位呈不依赖于温度的相关性（R2 = 0.48, P < 0.05）。线性判别分析效应大小确定硅藻（14.31%）为生物标志物组，表明光合作用驱动的碳交换促进了藻-菌共生。最后，共现网络分析确定假单胞菌和黄杆菌是ARG的潜在宿主。这些发现为优化生态净化池设计和制定有针对性的水生生态系统ARG控制方案提供了有价值的见解。
{"title":"Spatiotemporal dynamics of antibiotic resistance genes and bacterial communities in leaf biofilms of submerged macrophytes: Assessing wastewater treatment ecological pond","authors":"Tao Wu , Yaguang Li , Jibiao Zhang , Runze Tian , Lieyu Zhang","doi":"10.1016/j.ibiod.2025.106226","DOIUrl":"10.1016/j.ibiod.2025.106226","url":null,"abstract":"<div><div>Submerged macrophyte phyllosphere-associated biofilms serve as a critical reservoirs and potential transmission vectors for antibiotic resistance genes (ARGs), potentially exacerbating ecological risk in aquatic ecosystems. In this study, metagenomic sequencing and microbial community profilingwere employed to systematically investigate the spatiotemporal ARGs dynamics in <em>Vallisneria natans</em> phyllosphere-associated biofilms within an ecological purification pond. Key findings identified that multidrug resistance (MDR) genes constituted 39 % of the total detected ARGs in the phyllosphere-associated biofilms, exhibiting 11.3 % higher abundance compared to the aquatic biofilms (35 % of total detected ARGs). Principal coordinates analysis demonstrated significant segregation between the phyllosphere and adjacent water biofilm resistomes, explaining 48.76 % of the variance and indicating plant-mediated selection of resistant microorganisms via microenvironmental modification. Seasonal variation predominates over spatial in structuring microbiota and ARGs, with taxa-specific monthly shifts. Microbial community profiling identified <em>Pseudomonas</em> (50.8 %) and <em>Bacteroidetes</em> (11.35 %) as the dominant phyllosphere taxa, exhibiting significant correlations with key environmental parameters. Specifically, <em>Pseudomonas</em> abundance positively correlated with water temperature (R<sup>2</sup> = 0.51, P < 0.01), while <em>Bacteroidetes</em> showed a temperature-independent association with the oxidation-reduction potential (R<sup>2</sup> = 0.48, P < 0.05). Linear discriminant analysis effect size identified <em>Diatoms</em> (14.31 %) as a biomarker group, suggesting that photosynthesis-driven carbon exchange enhances algae-bacteria symbiosis. Finally, co-occurrence network analysis established <em>Pseudomonas</em> and <em>Flavobacterium</em> as the potential ARG hosts. These findings provide valuable insights for optimizing the design of ecological purification ponds and developing targeted ARG control protocols in aquatic ecosystems.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106226"},"PeriodicalIF":4.1,"publicationDate":"2025-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145325854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-09DOI: 10.1016/j.ibiod.2025.106225
Qianwei Li, Hairun Ma, Miao Zhang, Biao Wei, Daoqing Liu
Microplastics (MPs) with high surface area and reactivity readily bind microbial proteins to form the environment's MP–protein corona complexes (MP-PCs). Here, MPs leached from disposable face masks were characterized and incubated with extracellular proteins from Staphylococcus amber (S. amber) to induce MP-PCs formation. SDS-PAGE and microplate assays confirmed the variability of the MP-PCs, while chemical analysis revealed the presence of six detectable heavy metals (Cu, Fe, Mn, Pb, Cr, Zn) and slight pH changes in the leachates. The formation of MP-PCs facilitates the adsorption of heavy metals onto MPs and modulates MP-cell interactions, thereby enhancing the generation of bacterial reactive oxygen species (ROS). Moreover, the ROS produced by bacteria, catalyzed by transition metals adsorbed on the protein corona, contribute to the degradation of MPs through a Fenton-like reaction. These findings underscore the complex ecological risks associated with mask-derived MPs, which not only inhibit microbial growth but also accelerate their environmental transformation.
{"title":"Synergistic effects of protein coronas and heavy metals on ROS generation: Implications for microplastic-microbe interactions","authors":"Qianwei Li, Hairun Ma, Miao Zhang, Biao Wei, Daoqing Liu","doi":"10.1016/j.ibiod.2025.106225","DOIUrl":"10.1016/j.ibiod.2025.106225","url":null,"abstract":"<div><div>Microplastics (MPs) with high surface area and reactivity readily bind microbial proteins to form the environment's MP–protein corona complexes (MP-PCs). Here, MPs leached from disposable face masks were characterized and incubated with extracellular proteins from <em>Staphylococcus amber</em> (<em>S. amber</em>) to induce MP-PCs formation. SDS-PAGE and microplate assays confirmed the variability of the MP-PCs, while chemical analysis revealed the presence of six detectable heavy metals (Cu, Fe, Mn, Pb, Cr, Zn) and slight pH changes in the leachates. The formation of MP-PCs facilitates the adsorption of heavy metals onto MPs and modulates MP-cell interactions, thereby enhancing the generation of bacterial reactive oxygen species (ROS). Moreover, the ROS produced by bacteria, catalyzed by transition metals adsorbed on the protein corona, contribute to the degradation of MPs through a Fenton-like reaction. These findings underscore the complex ecological risks associated with mask-derived MPs, which not only inhibit microbial growth but also accelerate their environmental transformation.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106225"},"PeriodicalIF":4.1,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-08DOI: 10.1016/j.ibiod.2025.106224
Yufei Wu , Ziwei Jiang , Liang Ma , Xiaodong Wu , Qian Lu , Shuying Zang
Biochar amendment to soil is regarded as a promising approach to enhance soil carbon sequestration in agroforestry ecosystems. However, the effects of biochar on the mineralization of soil organic carbon (SOC) in permafrost-affected forest soils and their regulating mechanisms remain unknown. Here, humus layer soil samples from a permafrost-affected Larix gmelinii forest were incubated with biochar additions of CK (no biochar), 2 % (BC2), 4 % (BC4), and 8 % (BC8). Biochar reduced SOC mineralization rates by 4.72 %–7.02 %, with concurrent increases in soil total organic carbon (8.8 %–28.8 %) and dissolved organic carbon (1.5–3.4 times). Soil substrates (NH4+-N, pH, cation exchange capacity, electrical conductivity) and enzyme activities (dehydrogenase, polyphenol oxidase, urease) followed similar trends. Bacterial co-occurrence networks exhibited enhanced complexity and stability (e.g., network size, connectivity, modules, keystone species), with community assembly shifting from deterministic toward stochastic processes. The partial least squares structural equation modeling revealed that biochar might mitigate the SOC mineralization by reducing microbial activity through enhanced bacterial synergistic effects. These results highlight the importance of incorporating wildfire-produced biochar into the projections of permafrost carbon cycle.
{"title":"Enhanced stability of bacterial co-occurrence networks to biochar amendment reduces soil carbon mineralization in permafrost-affected soils","authors":"Yufei Wu , Ziwei Jiang , Liang Ma , Xiaodong Wu , Qian Lu , Shuying Zang","doi":"10.1016/j.ibiod.2025.106224","DOIUrl":"10.1016/j.ibiod.2025.106224","url":null,"abstract":"<div><div>Biochar amendment to soil is regarded as a promising approach to enhance soil carbon sequestration in agroforestry ecosystems. However, the effects of biochar on the mineralization of soil organic carbon (SOC) in permafrost-affected forest soils and their regulating mechanisms remain unknown. Here, humus layer soil samples from a permafrost-affected Larix gmelinii forest were incubated with biochar additions of CK (no biochar), 2 % (BC2), 4 % (BC4), and 8 % (BC8). Biochar reduced SOC mineralization rates by 4.72 %–7.02 %, with concurrent increases in soil total organic carbon (8.8 %–28.8 %) and dissolved organic carbon (1.5–3.4 times). Soil substrates (NH<sub>4</sub><sup>+</sup>-N, pH, cation exchange capacity, electrical conductivity) and enzyme activities (dehydrogenase, polyphenol oxidase, urease) followed similar trends. Bacterial co-occurrence networks exhibited enhanced complexity and stability (e.g., network size, connectivity, modules, keystone species), with community assembly shifting from deterministic toward stochastic processes. The partial least squares structural equation modeling revealed that biochar might mitigate the SOC mineralization by reducing microbial activity through enhanced bacterial synergistic effects. These results highlight the importance of incorporating wildfire-produced biochar into the projections of permafrost carbon cycle.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106224"},"PeriodicalIF":4.1,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-06DOI: 10.1016/j.ibiod.2025.106223
Muna Faeq Ali , Nahla Sh. Ajeel , Hasanain Saad Alhares , Sabah J. Mohammed , Mohanad J. M-Ridha
This study investigated phytoremediation of Congo red (CR) and methyl orange (MO) dye-contaminated water samples with Ceratophyllum demersum L. (coontail). Phytotoxicity assessments were also conducted to clarify the effects of dye concentrations on the growth and half-life of the plant. Based on the results, the 100 mg/L dye killed half of the plant (half-life) within 27 days. Increased dye concentration and exposure period also led to elevated toxicity in the plants. The results indicated that the dyes negatively affected plant growth. Conversely, incorporating NPK nutrients contributed to the plants overcoming toxicity and enhanced their growth. Furthermore, the MO dye exhibited fewer negative effects on the plant than the CR dye. Nevertheless, the phytoremediation process applied was successful. A 20 g of the coontail plant (dye solution volume = 5 L, initial pH = 7.0, initial dye level = 25 mg/L) dye removal percentages 100 % and 98 % CR and MO dyes during 15 days of exposure, respectively. FTIR data revealed that the various functional groups on the plant surface enabled coontail to absorb dyes from aqueous solutions, including carboxyl and carbonyl groups. Comparisons of control (without dye) and exposed (25 mg/L of initial dye concentration) coontail FESEM images demonstrated considerably altered morphological properties during phytoremediation of the dyes. These changes indicated effective loading of the dye onto the surfaces of the coontail samples. The uptake of dyes by coontail follows the Michaelis-Menten kinetics, indicating that adsorption occurs through a limited number of active sites on the plant's surface. Consequently, coontail is a notably efficient plant, applicable in eradicating dye-contaminated wastewater.
{"title":"Phytoremediation of Congo red and methyl orange dye-contaminated water with the coontail Ceratophyllum demersum aquatic plant","authors":"Muna Faeq Ali , Nahla Sh. Ajeel , Hasanain Saad Alhares , Sabah J. Mohammed , Mohanad J. M-Ridha","doi":"10.1016/j.ibiod.2025.106223","DOIUrl":"10.1016/j.ibiod.2025.106223","url":null,"abstract":"<div><div>This study investigated phytoremediation of Congo red (CR) and methyl orange (MO) dye-contaminated water samples with <em>Ceratophyllum demersum</em> L. (coontail). Phytotoxicity assessments were also conducted to clarify the effects of dye concentrations on the growth and half-life of the plant. Based on the results, the 100 mg/L dye killed half of the plant (half-life) within 27 days. Increased dye concentration and exposure period also led to elevated toxicity in the plants. The results indicated that the dyes negatively affected plant growth. Conversely, incorporating NPK nutrients contributed to the plants overcoming toxicity and enhanced their growth. Furthermore, the MO dye exhibited fewer negative effects on the plant than the CR dye. Nevertheless, the phytoremediation process applied was successful. A 20 g of the coontail plant (dye solution volume = 5 L, initial pH = 7.0, initial dye level = 25 mg/L) dye removal percentages 100 % and 98 % CR and MO dyes during 15 days of exposure, respectively. FTIR data revealed that the various functional groups on the plant surface enabled coontail to absorb dyes from aqueous solutions, including carboxyl and carbonyl groups. Comparisons of control (without dye) and exposed (25 mg/L of initial dye concentration) coontail FESEM images demonstrated considerably altered morphological properties during phytoremediation of the dyes. These changes indicated effective loading of the dye onto the surfaces of the coontail samples. The uptake of dyes by coontail follows the Michaelis-Menten kinetics, indicating that adsorption occurs through a limited number of active sites on the plant's surface. Consequently, coontail is a notably efficient plant, applicable in eradicating dye-contaminated wastewater.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106223"},"PeriodicalIF":4.1,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145270883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01DOI: 10.1016/j.ibiod.2025.106222
Lei Wu , Ming-Shu Zhang , Zhen-Dong Yang , Zhi-Wei Li , Jun-Jin Deng , Xiao-Chun Luo
Maintaining sulfur homeostasis is critical for cell viability. However, sulfide transmembrane transportation is not well revealed. This study identifies SsTauE, a CPA/AT family sulfite exporter in Streptomyces sp. SCUT-3, a potent feather degrader. sstauE and cysteine dioxygenase gene cdo1 form an operon up-regulated by cysteine. Overexpression of sstauE significantly enhances sulfite efflux and sulfite resistance. Site-directed mutagenesis reveals that Lys289 and Arg292, crucial for Lys-Arg-Val hydrogen bond bridge, are essential for core subdomains formation and function of SstauE. Co-overexpression with sstauE alleviates the sulfite toxicity from cdo1 overexpression alone, increases extracellular sulfite production 2.5-fold and facilitates feather degradation by enhancing disulfide bond breakdown, which increases 2.1 times total keratin amino acid and polypeptide recovery compared to wild-type at day 2. This study elucidates the coordinated regulation of sulfite production by CDO1 and efflux SsTauE in Streptomyces, providing insights into sulfur homeostasis and offering potential strategies for improved waste feather biodegradation.
{"title":"Sulfite exporter SsTauE enhances bacterial feather degradation by maintaining sulfur homeostasis","authors":"Lei Wu , Ming-Shu Zhang , Zhen-Dong Yang , Zhi-Wei Li , Jun-Jin Deng , Xiao-Chun Luo","doi":"10.1016/j.ibiod.2025.106222","DOIUrl":"10.1016/j.ibiod.2025.106222","url":null,"abstract":"<div><div>Maintaining sulfur homeostasis is critical for cell viability. However, sulfide transmembrane transportation is not well revealed. This study identifies SsTauE, a CPA/AT family sulfite exporter in <em>Streptomyces</em> sp. SCUT-3, a potent feather degrader. <em>sstauE</em> and cysteine dioxygenase gene <em>cdo1</em> form an operon up-regulated by cysteine. Overexpression of <em>sstauE</em> significantly enhances sulfite efflux and sulfite resistance. Site-directed mutagenesis reveals that Lys289 and Arg292, crucial for Lys-Arg-Val hydrogen bond bridge, are essential for core subdomains formation and function of SstauE. Co-overexpression with <em>sstauE</em> alleviates the sulfite toxicity from <em>cdo1</em> overexpression alone, increases extracellular sulfite production 2.5-fold and facilitates feather degradation by enhancing disulfide bond breakdown, which increases 2.1 times total keratin amino acid and polypeptide recovery compared to wild-type at day 2. This study elucidates the coordinated regulation of sulfite production by CDO1 and efflux SsTauE in <em>Streptomyces</em>, providing insights into sulfur homeostasis and offering potential strategies for improved waste feather biodegradation.</div></div>","PeriodicalId":13643,"journal":{"name":"International Biodeterioration & Biodegradation","volume":"207 ","pages":"Article 106222"},"PeriodicalIF":4.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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