Pub Date : 2026-04-01Epub Date: 2026-01-26DOI: 10.1016/j.biortech.2026.134097
Hongwei Li , Xin Sun , Haocheng Li , Binchen Mao , Pengfei Li , Lei Ye
The microalgal biofuel development is often hindered by the inherent trade-off between biomass growth and lipid accumulation. Argon-, air-, and mixed-gas atmospheric and room-temperature plasma (ARTP) mutagenesis produced distinct temporal reactive oxygen species (ROS) profiles in Chlorella sorokiniana. A superior mutant, MixMAX10, generated through argon/air plasma mutagenesis plus malonic acid (MA), delayed antioxidant response that utilized mid-cultivation ROS spikes as signaling triggers. Time-series transcriptomics revealed mid-phase transcriptional reprogramming, deciphered by Weighted Gene Co-expression Network Analysis (WGCNA) to identify core gene modules (turquoise, green, blue) and hub genes (CWC24, PDHB) linking redox signaling to metabolic rewiring, coordinating upregulation of pathways governing acetyl-CoA supply, fatty acid biosynthesis, and redox homeostasis. It redirects carbon flux toward triacylglycerol (TAG) synthesis, achieving 66% TAG content alongside robust carbon fixation. This study reveals a tunable redox-mediated mechanism to decouple growth from storage, enabling targeted breeding of high-performance microalgae.
{"title":"Divergent mutagenic strategies converge on temporal redox signaling to unlock lipid and carbon synergy in microalgae","authors":"Hongwei Li , Xin Sun , Haocheng Li , Binchen Mao , Pengfei Li , Lei Ye","doi":"10.1016/j.biortech.2026.134097","DOIUrl":"10.1016/j.biortech.2026.134097","url":null,"abstract":"<div><div>The microalgal biofuel development is often hindered by the inherent trade-off between biomass growth and lipid accumulation. Argon-, air-, and mixed-gas atmospheric and room-temperature plasma (ARTP) mutagenesis produced distinct temporal reactive oxygen species (ROS) profiles in <em>Chlorella sorokiniana</em>. A superior mutant, MixMAX10, generated through argon/air plasma mutagenesis plus malonic acid (MA), delayed antioxidant response that utilized mid-cultivation ROS spikes as signaling triggers. Time-series transcriptomics revealed mid-phase transcriptional reprogramming, deciphered by Weighted Gene Co-expression Network Analysis (WGCNA) to identify core gene modules (turquoise, green, blue) and hub genes (CWC24, <em>PDHB</em>) linking redox signaling to metabolic rewiring, coordinating upregulation of pathways governing acetyl-CoA supply, fatty acid biosynthesis, and redox homeostasis. It redirects carbon flux toward triacylglycerol (TAG) synthesis, achieving 66% TAG content alongside robust carbon fixation. This study reveals a tunable redox-mediated mechanism to decouple growth from storage, enabling targeted breeding of high-performance microalgae.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134097"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-01-18DOI: 10.1016/j.biortech.2026.134016
Valentina Pucciarelli , Dolores Ianniciello , Eric Schmitt , Carmen Scieuzo , Patrizia Falabella
The urgent need for sustainable energy is intensifying research on biodiesel feedstocks that cut environmental impact and fossil dependence. Among these, Hermetia illucens upcycles organic waste into lipid-rich biomass, enabling a circular bioeconomy. Compared with first- to fourth-generation feedstocks (edible oils, waste cooking oils/residues, microalgae, engineered microorganisms), it avoids food competition and dedicated cropland, supports diet-tunable lipid profiles, requires no water-intensive cultivation, and has a short production cycle; indicative carbon footprint values (∼0.8 kg CO2 eq/kg lipid) suggest advantages over conventional oils. This review critically examines the fuel properties of H. illucens biodiesel and benchmarks them across feedstocks. Under optimized conditions, literature-reported yields reach ∼94–98 % (defined here as FAME/biodiesel mass yield on a lipid-feedstock basis). The fuel shows cetane ∼50–58, kinematic viscosity 4.0–5.2 mm2/s (generally compliant, near the EN upper bound), and flash point >120 °C; water and total glycerol meet international standards. Oxidative stability reaches 7.7 h with antioxidants (meets ASTM ≥3h, typically below EN ≥8h without optimization). In H. illucens biodiesel, the acid value is usually >0.50 mg KOH/g; however, standard treatments bring it within limits. In H. illucens, diet can be leveraged to tailor both the fatty-acid profile and the lipid yield for target applications. Preliminary evidence on process energy and costs across extraction and transesterification routes indicates that economics remain feedstock-driven and depend on scale, heat/solvent recovery, and enzyme reuse. In sum, H. illucens is a scalable platform for waste-derived biodiesel; this review distills evidence and practical levers to close remaining gaps and accelerate adoption.
{"title":"Hermetia illucens as an innovative feedstock for biodiesel: properties, production techniques, and regulatory compliance","authors":"Valentina Pucciarelli , Dolores Ianniciello , Eric Schmitt , Carmen Scieuzo , Patrizia Falabella","doi":"10.1016/j.biortech.2026.134016","DOIUrl":"10.1016/j.biortech.2026.134016","url":null,"abstract":"<div><div>The urgent need for sustainable energy is intensifying research on biodiesel feedstocks that cut environmental impact and fossil dependence. Among these, <em>Hermetia illucens</em> upcycles organic waste into lipid-rich biomass, enabling a circular bioeconomy. Compared with first- to fourth-generation feedstocks (edible oils, waste cooking oils/residues, microalgae, engineered microorganisms), it avoids food competition and dedicated cropland, supports diet-tunable lipid profiles, requires no water-intensive cultivation, and has a short production cycle; indicative carbon footprint values (∼0.8 kg CO<sub>2</sub> eq/kg lipid) suggest advantages over conventional oils. This review critically examines the fuel properties of <em>H. illucens</em> biodiesel and benchmarks them across feedstocks. Under optimized conditions, literature-reported yields reach ∼94–98 % (defined here as FAME/biodiesel mass yield on a lipid-feedstock basis). The fuel shows cetane ∼50–58, kinematic viscosity 4.0–5.2 mm<sup>2</sup>/s (generally compliant, near the EN upper bound), and flash point >120 °C; water and total glycerol meet international standards. Oxidative stability reaches 7.7 h with antioxidants (meets ASTM ≥3h, typically below EN ≥8h without optimization). In <em>H. illucens</em> biodiesel, the acid value is usually >0.50 mg KOH/g; however, standard treatments bring it within limits. In <em>H. illucens</em>, diet can be leveraged to tailor both the fatty-acid profile and the lipid yield for target applications. Preliminary evidence on process energy and costs across extraction and transesterification routes indicates that economics remain feedstock-driven and depend on scale, heat/solvent recovery, and enzyme reuse. In sum, <em>H. illucens</em> is a scalable platform for waste-derived biodiesel; this review distills evidence and practical levers to close remaining gaps and accelerate adoption.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134016"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-01-19DOI: 10.1016/j.biortech.2026.134050
Menglong Liao, Ye Qiu, Yunlong Ji, Wenqing Liu, Jun Ma, Guohong Liu, Yujie Feng
Polyethylene terephthalate (PET) has broad environmental applications, yet its inherent poor conductivity limits its utility in microbial fuel cell (MFC). This study addressed the need for cost-effective and conductive PET-supported materials. In this study, PET-supported three-dimensional materials were used as a substrate, introducing the conductive coating layer that enhanced hydrophilicity, electrochemically active surface area, and decreased charge transfer resistance. The PET-supported cathode modified with polypyrrole (PPy) and carbon nanotubes (CNTs) achieved a maximal power density (758.2 mW/m2) with long-term operational stability for 4 months. The PET/PPy/CNTs cathode exhibited 2.23-fold higher nitrate removal efficiency than carbon felt cathode. Notably, the average viability of biofilm on the internal surface of PET/PPy/CNTs (63.5%) was 2.89-fold higher than carbon felt. Furthermore, the PET/PPy/CNTs demonstrated significant cost-effectiveness with a cost of approximately $2.04/m2. Considering the superior bioelectrochemical performance, low costs, and low life cycle environmental impacts, the PET-supported cathode demonstrates notable potential for enhancing MFC performance.
{"title":"Construction of conductive modified polyethylene terephthalate-supported cathode in microbial fuel cell for nitrate removal","authors":"Menglong Liao, Ye Qiu, Yunlong Ji, Wenqing Liu, Jun Ma, Guohong Liu, Yujie Feng","doi":"10.1016/j.biortech.2026.134050","DOIUrl":"10.1016/j.biortech.2026.134050","url":null,"abstract":"<div><div>Polyethylene terephthalate (PET) has broad environmental applications, yet its inherent poor conductivity limits its utility in microbial fuel cell (MFC). This study addressed the need for cost-effective and conductive PET-supported materials. In this study, PET-supported three-dimensional materials were used as a substrate, introducing the conductive coating layer that enhanced hydrophilicity, electrochemically active surface area, and decreased charge transfer resistance. The PET-supported cathode modified with polypyrrole (PPy) and carbon nanotubes (CNTs) achieved a maximal power density (758.2 mW/m<sup>2</sup>) with long-term operational stability for 4 months. The PET/PPy/CNTs cathode exhibited 2.23-fold higher nitrate removal efficiency than carbon felt cathode. Notably, the average viability of biofilm on the internal surface of PET/PPy/CNTs (63.5%) was 2.89-fold higher than carbon felt. Furthermore, the PET/PPy/CNTs demonstrated significant cost-effectiveness with a cost of approximately $2.04/m<sup>2</sup>. Considering the superior bioelectrochemical performance, low costs, and low life cycle environmental impacts, the PET-supported cathode demonstrates notable potential for enhancing MFC performance.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134050"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-01-14DOI: 10.1016/j.biortech.2026.134018
Jiayuan Jia , Ziyu Dai , Yinglei Han , Hemant Choudhary , Guoliang Yuan , John M. Gladden , Blake A. Simmons , Scott E. Baker , Jon K. Magnuson , Joonhoon Kim
Lignin is the largest renewable source of aromatic carbon, yet its heterogeneity and recalcitrance limit its use in higher-value bioconversion processes. In this study, Aspergillus niger was engineered to enable the bioconversion of lignin-derived aromatics and base-catalyzed depolymerized (BCD) lignin streams into malic acid, a value-added C4 dicarboxylic acid with broad industrial relevance. Overexpression of the C4 dicarboxylate transporter C4T318 from Aspergillus oryzae enhanced malic acid secretion, while medium optimization under buffered conditions further improved the production. The engineered strain efficiently assimilated representative lignin-derived aromatics, including 4-hydroxybenzoic acid and p-coumaric acid, producing up to 3.9 g/L malic acid. Conversion of BCD lignin liquors from poplar and sorghum demonstrated effective utilization of heterogeneous aromatic mixtures, generating up to 0.82 g/L malic acid. This work demonstrates direct fungal conversion of real lignin streams into malic acid and establishes A. niger as a promising platform for sustainable lignin valorization.
{"title":"Microbial valorization of lignin to malic acid by Aspergillus niger","authors":"Jiayuan Jia , Ziyu Dai , Yinglei Han , Hemant Choudhary , Guoliang Yuan , John M. Gladden , Blake A. Simmons , Scott E. Baker , Jon K. Magnuson , Joonhoon Kim","doi":"10.1016/j.biortech.2026.134018","DOIUrl":"10.1016/j.biortech.2026.134018","url":null,"abstract":"<div><div>Lignin is the largest renewable source of aromatic carbon, yet its heterogeneity and recalcitrance limit its use in higher-value bioconversion processes. In this study, <em>Aspergillus niger</em> was engineered to enable the bioconversion of lignin-derived aromatics and base-catalyzed depolymerized (BCD) lignin streams into malic acid, a value-added C4 dicarboxylic acid with broad industrial relevance. Overexpression of the C4 dicarboxylate transporter <em>C4T318</em> from <em>Aspergillus oryzae</em> enhanced malic acid secretion, while medium optimization under buffered conditions further improved the production. The engineered strain efficiently assimilated representative lignin-derived aromatics, including 4-hydroxybenzoic acid and <em>p</em>-coumaric acid, producing up to 3.9 g/L malic acid. Conversion of BCD lignin liquors from poplar and sorghum demonstrated effective utilization of heterogeneous aromatic mixtures, generating up to 0.82 g/L malic acid. This work demonstrates direct fungal conversion of real lignin streams into malic acid and establishes <em>A. niger</em> as a promising platform for sustainable lignin valorization.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134018"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145987597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-01-20DOI: 10.1016/j.biortech.2026.134049
Hao Han , Shuailing Wang , Lele Zhou , Siying Li , Jingfei Huang , Xingxing Peng
This study systematically investigated the impacts of seven common tire additives (TAs) and their derivatives on the performance and microbial ecology of an activated sludge system exposed to environmental concentrations (0.2–20.0 μg/L) over 160 days. While most individual TAs showed minimal effects, the mixture of TAs (MIX) and 2-((4-Methylpentan-2-yl)amino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione (6PPD-Q) significantly inhibited nitrogen removal efficiency. At 20.0 μg/L, the abundances of key nitrification and denitrification genes (amoA, nirK, nirS, nosZ) were markedly suppressed, leading to reductions in NH4+-N (12–14%) and total nitrogen (18–23%) removal efficiencies. The impairment was associated with elevated oxidative stress level, as indicated by a sharp increase in reactive oxygen species (0.9–1.1 fold) and lactate dehydrogenase (1.5–2.1 fold) release, alongside suppressed adenosine triphosphate (ATP) synthesis. Concurrently, sludge settleability deteriorated and mixed liquor volatile suspended solids (MLVSS) decreased, which correlated with reduced sludge hydrophobicity and enhanced hydrogen bond intensity (3435 cm−1). Microbial community restructuring was observed, with tolerant genera (e.g., Comamonadaceae, Rhodobacteraceae) increasing, while key nitrogen-removing genera (e.g., Nitrosomonas, Thauera) decreased. Three-dimensional fluorescence spectroscopy analysis revealed a decline in tryptophan and tyrosine like proteins in tightly bound extracellular polymeric substances. Molecular docking demonstrated that 6PPD-Q exhibited the strongest binding affinity to tryptophan and tyrosine synthases, suggesting a high potential for enzymatic interference even at low concentrations. This study demonstrated that MIX and 6PPD-Q, at environmental concentrations, significantly affect activated sludge systems and investigated the mechanisms involved, thereby providing important evidence for the ecological risk assessment of such pollutants during wastewater treatment.
{"title":"Insights into impact of tire additives on activated sludge systems: Treatment performance, extracellular polymeric substances, and microbial community","authors":"Hao Han , Shuailing Wang , Lele Zhou , Siying Li , Jingfei Huang , Xingxing Peng","doi":"10.1016/j.biortech.2026.134049","DOIUrl":"10.1016/j.biortech.2026.134049","url":null,"abstract":"<div><div>This study systematically investigated the impacts of seven common tire additives (TAs) and their derivatives on the performance and microbial ecology of an activated sludge system exposed to environmental concentrations (0.2–20.0 μg/L) over 160 days. While most individual TAs showed minimal effects, the mixture of TAs (MIX) and 2-((4-Methylpentan-2-yl)amino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione (6PPD-Q) significantly inhibited nitrogen removal efficiency. At 20.0 μg/L, the abundances of key nitrification and denitrification genes (<em>amoA</em>, <em>nirK</em>, <em>nirS</em>, <em>nosZ</em>) were markedly suppressed, leading to reductions in NH<sub>4</sub><sup>+</sup>-N (12–14%) and total nitrogen (18–23%) removal efficiencies. The impairment was associated with elevated oxidative stress level, as indicated by a sharp increase in reactive oxygen species (0.9–1.1 fold) and lactate dehydrogenase (1.5–2.1 fold) release, alongside suppressed adenosine triphosphate (ATP) synthesis. Concurrently, sludge settleability deteriorated and mixed liquor volatile suspended solids (MLVSS) decreased, which correlated with reduced sludge hydrophobicity and enhanced hydrogen bond intensity (3435 cm<sup>−1</sup>). Microbial community restructuring was observed, with tolerant genera (e.g., <em>Comamonadaceae</em>, <em>Rhodobacteraceae</em>) increasing, while key nitrogen-removing genera (e.g., <em>Nitrosomonas</em>, <em>Thauera</em>) decreased. Three-dimensional fluorescence spectroscopy analysis revealed a decline in tryptophan and tyrosine like proteins in tightly bound extracellular polymeric substances. Molecular docking demonstrated that 6PPD-Q exhibited the strongest binding affinity to tryptophan and tyrosine synthases, suggesting a high potential for enzymatic interference even at low concentrations. This study demonstrated that MIX and 6PPD-Q, at environmental concentrations, significantly affect activated sludge systems and investigated the mechanisms involved, thereby providing important evidence for the ecological risk assessment of such pollutants during wastewater treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134049"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}
Acidic mine drainage (AMD) requires efficient and controllable pH pretreatment to ensure the stability of subsequent remediation processes. Herein, a fully polysaccharide-based imine–boronate double-network hydrogel (PVA/QCMC/DSA/BA) was developed as a multifunctional pH-regulating material, in which the crosslinking degree could be precisely tuned. The hydrogel exhibited bidirectional and mild pH regulation, neutralizing acidic solutions (pH 3.0) to approximately 8.0 and moderating alkaline solutions (pH 11.0) to ∼9.5 without abrupt pH overshooting. Moreover, a CaCO3-loaded hydrogel variant was developed to further enhance sustained neutralization performance under highly acidic conditions. By adjusting the crosslinking degree, the swelling ratio of the hydrogel could reach up to 4110.3 %, while the pH adjustment rate varied by up to 50 %, demonstrating a controllable structure–function relationship. In addition, the hydrogel exhibited an elongation at break exceeding 1000 %, excellent self-healing efficiency (72–100 %), and strong antibacterial activity with inhibition efficiencies above 99 %. A dose–response model based on consumed protons (Δn(H+)) was established to predict pH regulation performance under AMD conditions, highlighting the potential of this hydrogel system as a practical pretreatment material for acidic wastewater.
{"title":"Multifunctional imine-boronate double network hydrogels for acidic wastewater pretreatment, featuring crosslinking degree–dependent structural properties","authors":"Yu Wang, Chunrong Wang, Yansen Wei, Saisai Guo, Qi Zhang, Jianbing Wang","doi":"10.1016/j.biortech.2026.134058","DOIUrl":"10.1016/j.biortech.2026.134058","url":null,"abstract":"<div><div>Acidic mine drainage (AMD) requires efficient and controllable pH pretreatment to ensure the stability of subsequent remediation processes. Herein, a fully polysaccharide-based imine–boronate double-network hydrogel (PVA/QCMC/DSA/BA) was developed as a multifunctional pH-regulating material, in which the crosslinking degree could be precisely tuned. The hydrogel exhibited bidirectional and mild pH regulation, neutralizing acidic solutions (pH 3.0) to approximately 8.0 and moderating alkaline solutions (pH 11.0) to ∼9.5 without abrupt pH overshooting. Moreover, a CaCO<sub>3</sub>-loaded hydrogel variant was developed to further enhance sustained neutralization performance under highly acidic conditions. By adjusting the crosslinking degree, the swelling ratio of the hydrogel could reach up to 4110.3 %, while the pH adjustment rate varied by up to 50 %, demonstrating a controllable structure–function relationship. In addition, the hydrogel exhibited an elongation at break exceeding 1000 %, excellent self-healing efficiency (72–100 %), and strong antibacterial activity with inhibition efficiencies above 99 %. A dose–response model based on consumed protons (Δn(H<sup>+</sup>)) was established to predict pH regulation performance under AMD conditions, highlighting the potential of this hydrogel system as a practical pretreatment material for acidic wastewater.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"445 ","pages":"Article 134058"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-02-07DOI: 10.1016/j.biortech.2026.134152
Min Li , Xiuxia Meng , Erqi Nie , Dongxue Lu , Rongbo Guo , Shanfei Fu , Jianhua Guo
Volatile fatty acid accumulation from rapid degradation of biodegradable substrates is a key challenge in anaerobic digestion. Methanosarcina barkeri shows exceptional adaptability and acetate stress tolerance, but the mechanisms are not fully understood at the single-cell level. Using heavy water-labeled single-cell Raman spectroscopy (D2O-SCRS), we examined the physiological and metabolic responses of M. barkeri to different acetate concentration gradients. High acetate levels (200 mM) inhibited methane production and microbial growth. Raman analysis revealed concentration-dependent inhibition, with the C-D ratio (metabolic activity marker) dropping below 10% at 200 mM, compared to 10–30% at 50 and 100 mM. Multivariate analysis showed metabolic reprogramming and distinct phenotypic transitions under acetate stress. Principal component–linear discriminant analysis identified biomarkers for nucleic acids, proteins, and lipids, suggesting disruption of cellular functions. Together, these findings offer single-cell insights into M. barkeri’s adaptive strategies and highlight the value of D2O-SCRS in studying archaeal responses in anaerobic ecosystems.
{"title":"Deciphering acetate stress responses in methanogen using D2O-Labeled Single-Cell Raman spectroscopy","authors":"Min Li , Xiuxia Meng , Erqi Nie , Dongxue Lu , Rongbo Guo , Shanfei Fu , Jianhua Guo","doi":"10.1016/j.biortech.2026.134152","DOIUrl":"10.1016/j.biortech.2026.134152","url":null,"abstract":"<div><div>Volatile fatty acid accumulation from rapid degradation of biodegradable substrates is a key challenge in anaerobic digestion. <em>Methanosarcina barkeri</em> shows exceptional adaptability and acetate stress tolerance, but the mechanisms are not fully understood at the single-cell level. Using heavy water-labeled single-cell Raman spectroscopy (D<sub>2</sub>O-SCRS), we examined the physiological and metabolic responses of <em>M. barkeri</em> to different acetate concentration gradients. High acetate levels (200 mM) inhibited methane production and microbial growth. Raman analysis revealed concentration-dependent inhibition, with the C-D ratio (metabolic activity marker) dropping below 10% at 200 mM, compared to 10–30% at 50 and 100 mM. Multivariate analysis showed metabolic reprogramming and distinct phenotypic transitions under acetate stress. Principal component–linear discriminant analysis identified biomarkers for nucleic acids, proteins, and lipids, suggesting disruption of cellular functions. Together, these findings offer single-cell insights into <em>M. barkeri’s</em> adaptive strategies and highlight the value of D<sub>2</sub>O-SCRS in studying archaeal responses in anaerobic ecosystems.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134152"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146138843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-02-10DOI: 10.1016/j.biortech.2026.134181
Jiantao Ji , Qiyue Wang , Feiyue Hu , Haosen Yang , Ying Li , Guanqi Wu , Yongen Dong , Jinying Du , Huiru Li , Bo Shen , Bo Wang
The widespread use of antibiotics has led to their persistence in aquatic environments, posing serious challenges to biological treatment systems. This study systematically compared the performance and adaptive mechanisms of partial denitrification (PD)/anaerobic ammonium oxidation (anammox) and single anammox systems under long-term sulfamethoxazole (SMX) stress over 193 days. At an influent SMX concentration of 3 mg/L, the PD/anammox system retained 75% of its initial total inorganic nitrogen (TIN) removal efficiency, significantly higher than that of the single anammox system (49%). The PD/anammox achieved an SMX degradation efficiency of 80%, substantially exceeding that of the single system (39%). Metagenomic analyses revealed higher abundances of key nitrogen metabolism genes (hzs, hdh, narG/H/I, napA/B, nirK/S) and SMX degradation genes (sadA, sadC, tmoABCDEF, dmpB/D) in the PD/anammox system. The enhanced performance was closely associated with the enrichment of the denitrifying microbiome (e.g., Thauera, Zoogloea, unclassified_f_Rhodocyclaceae), which provided a stable nitrite supply and carried SMX degradation genes. Both systems relied on extracellular polymeric substances (EPS) as a protective barrier under low SMX stress (1 mg/L). Under higher SMX concentrations (>1 mg/L), the PD/anammox system exhibited dynamic enrichment of sulfonamide resistance genes (sul1). These results demonstrated the superiority of the PD/anammox system over the single anammox system. The combined effects of a diverse microbiome, multi-level stress-response mechanisms involving EPS and antibiotic resistance genes, and efficient functional gene expression make PD/anammox a robust and promising technology for the treatment of antibiotic-containing wastewater.
{"title":"Advantages of partial denitrification–anaerobic ammonium oxidation system under sulfamethoxazole stress: Adaptive mechanisms and synergistic metabolism","authors":"Jiantao Ji , Qiyue Wang , Feiyue Hu , Haosen Yang , Ying Li , Guanqi Wu , Yongen Dong , Jinying Du , Huiru Li , Bo Shen , Bo Wang","doi":"10.1016/j.biortech.2026.134181","DOIUrl":"10.1016/j.biortech.2026.134181","url":null,"abstract":"<div><div>The widespread use of antibiotics has led to their persistence in aquatic environments, posing serious challenges to biological treatment systems. This study systematically compared the performance and adaptive mechanisms of partial denitrification (PD)/anaerobic ammonium oxidation (anammox) and single anammox systems under long-term sulfamethoxazole (SMX) stress over 193 days. At an influent SMX concentration of 3 mg/L, the PD/anammox system retained 75% of its initial total inorganic nitrogen (TIN) removal efficiency, significantly higher than that of the single anammox system (49%). The PD/anammox achieved an SMX degradation efficiency of 80%, substantially exceeding that of the single system (39%). Metagenomic analyses revealed higher abundances of key nitrogen metabolism genes (<em>hzs, hdh, narG/H/I, napA/B, nirK/S</em>) and SMX degradation genes (<em>sadA, sadC, tmoABCDEF, dmpB/D</em>) in the PD/anammox system. The enhanced performance was closely associated with the enrichment of the denitrifying microbiome (e.g., <em>Thauera, Zoogloea, unclassified_f_Rhodocyclaceae</em>), which provided a stable nitrite supply and carried SMX degradation genes. Both systems relied on extracellular polymeric substances (EPS) as a protective barrier under low SMX stress (1 mg/L). Under higher SMX concentrations (>1 mg/L), the PD/anammox system exhibited dynamic enrichment of sulfonamide resistance genes (<em>sul1</em>). These results demonstrated the superiority of the PD/anammox system over the single anammox system. The combined effects of a diverse microbiome, multi-level stress-response mechanisms involving EPS and antibiotic resistance genes, and efficient functional gene expression make PD/anammox a robust and promising technology for the treatment of antibiotic-containing wastewater.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134181"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2026-04-01Epub Date: 2026-01-22DOI: 10.1016/j.biortech.2026.134065
Siqi Li , Hong Yan
Based on the carbon quantum dots (CQDs) derived from waste lignin, this study coupled them with visible light-responsive Zn0.75Cd0.25S (ZCS) and the catalytically active ZIF-67 to construct the ternary composite photocatalyst ZIF-67/ZCS/CQDs, aiming to suppress carrier recombination and broaden the light absorption range. The characterization results show that this composite system effectively integrates the catalytic activity of ZIF-67, the visible light absorption characteristics of ZCS, and the charge transfer advantages of CQDs, forming an efficient charge transfer channel. This design significantly enhances the separation and migration efficiency of photogenerated carriers, thereby greatly improving the performance of photocatalytic hydrogen production. This research provides new ideas for the design of highly efficient photocatalysts and also opens up new avenues for the high-value utilization of waste biomass.
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The environmental risk of azo dyes arises from their recalcitrant nature and potential carcinogenicity. Microbial fuel cells (MFCs) have emerged as a sustainable technology for concurrent wastewater treatment and renewable electricity generation, yet their efficiency is constrained by mass transfer limitations, low electron recovery, and the complex responses of microbial communities. This study evaluated the effects of free-fall influent (FF) mode on red soil MFCs treating the disazo dye Acid Red 73 (AR73). Compared with conventional operation, FF mode enhanced both pollutant removal and bioelectrochemical performance. The hydrodynamic impact of inflowing droplets increased cathodic dissolved oxygen by 44.7–45.8%, thereby promoting oxygen reduction. These physicochemical shifts mitigated cathodic polarization, resulting in a maximum power density of 2056 mW/m3 under dye-containing conditions. Coulombic efficiency also improved, reflecting more efficient electron recovery from organic substrates. GC–MS analysis identified the major degradation products in both FF and non-FF modes, revealing differences that clarified the AR73 degradation pathway. Microbial community analyses revealed that FF mode restructured both bacterial and fungal communities. Electroactive genera, including Anaeromyxobacter, Dechloromonas, Citrifermentans, and Caulobacter were enriched, together with organic degraders such as Xanthobacter, Methyloversatilis, Rhodoplanes, and Aquabacterium. Fungal communities, dominated by Ascomycota and Basidiomycota, also displayed functional shifts, with FF mode promoting the abundance of degradative taxa including Ganoderma, Nigrospora, and Sterigmatomyces. Overall, FF mode provides a hydrodynamic strategy that enhances both energy recovery and pollutant removal. These findings suggest that hydrodynamic intensification can improve the sustainability of wastewater treatment in bioelectrochemical systems.
{"title":"Hydrodynamic intensification of red soil microbial fuel cells: enhanced Acid Red 73 degradation and bioelectricity generation under free-fall influent","authors":"Yian Wang, Xinyue Fu, Hangzhi Liu, Yingying Dong, Dongdong Niu, Weina Wang, Genhe He","doi":"10.1016/j.biortech.2026.134187","DOIUrl":"10.1016/j.biortech.2026.134187","url":null,"abstract":"<div><div>The environmental risk of azo dyes arises from their recalcitrant nature and potential carcinogenicity. Microbial fuel cells (MFCs) have emerged as a sustainable technology for concurrent wastewater treatment and renewable electricity generation, yet their efficiency is constrained by mass transfer limitations, low electron recovery, and the complex responses of microbial communities. This study evaluated the effects of free-fall influent (FF) mode on red soil MFCs treating the disazo dye Acid Red 73 (AR73). Compared with conventional operation, FF mode enhanced both pollutant removal and bioelectrochemical performance. The hydrodynamic impact of inflowing droplets increased cathodic dissolved oxygen by 44.7–45.8%, thereby promoting oxygen reduction. These physicochemical shifts mitigated cathodic polarization, resulting in a maximum power density of 2056 mW/m<sup>3</sup> under dye-containing conditions. Coulombic efficiency also improved, reflecting more efficient electron recovery from organic substrates. GC–MS analysis identified the major degradation products in both FF and non-FF modes, revealing differences that clarified the AR73 degradation pathway. Microbial community analyses revealed that FF mode restructured both bacterial and fungal communities. Electroactive genera, including <em>Anaeromyxobacter</em>, <em>Dechloromonas</em>, <em>Citrifermentans</em>, and <em>Caulobacter</em> were enriched, together with organic degraders such as <em>Xanthobacter</em>, <em>Methyloversatilis</em>, <em>Rhodoplanes</em>, and <em>Aquabacterium</em>. Fungal communities, dominated by <em>Ascomycota</em> and <em>Basidiomycota</em>, also displayed functional shifts, with FF mode promoting the abundance of degradative taxa including <em>Ganoderma</em>, <em>Nigrospora</em>, and <em>Sterigmatomyces</em>. Overall, FF mode provides a hydrodynamic strategy that enhances both energy recovery and pollutant removal. These findings suggest that hydrodynamic intensification can improve the sustainability of wastewater treatment in bioelectrochemical systems.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"446 ","pages":"Article 134187"},"PeriodicalIF":9.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146186753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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