Pub Date : 2025-04-15DOI: 10.1016/j.biortech.2025.132551
Naassom Wagner Sales Morais , Marcos Vinícius Domingos Araújo da Silva , Rennan Guthierrez Nunes do Nascimento , Valdemiro Matsumura de Sousa , Mauricio Alves da Motta Sobrinho , André Bezerra dos Santos
This study evaluated the impact of graphene oxide functionalized with nano-magnetite (GO-Fe3O4) on the anaerobic treatment of swine wastewater (SW). The experiment was conducted in glass reactors with 200 mL of reaction volume, operating in fed-batch mode in three treatment cycles, each with 35 days. The evaluated doses of GO-Fe3O4 were 3 mg L-1 (1 mg gVSS-1) and 150 mg L-1 (50 mg gVSS-1). In the third cycle, GO-Fe3O4 (150 mg L-1) increased the biochemical methane potential by 17 %, the biogas production potential by 18 %, the methane production rate constant by 31 %, the maximum methane production rate by 32 %, and reduced the lag phase time by 25 %. Potential direct interspecies electron transfer partners are Midas g 156 and Clostridium sensu stricto 1 with Methanobacterium beijingense and Methanothrix soehngenii. GO-Fe3O4 is a powerful and unique material for improving methane and biogas production via SW anaerobic treatment.
{"title":"Impact of graphene oxide functionalized with nano-magnetite on swine wastewater anaerobic treatment","authors":"Naassom Wagner Sales Morais , Marcos Vinícius Domingos Araújo da Silva , Rennan Guthierrez Nunes do Nascimento , Valdemiro Matsumura de Sousa , Mauricio Alves da Motta Sobrinho , André Bezerra dos Santos","doi":"10.1016/j.biortech.2025.132551","DOIUrl":"10.1016/j.biortech.2025.132551","url":null,"abstract":"<div><div>This study evaluated the impact of graphene oxide functionalized with nano-magnetite (GO-Fe<sub>3</sub>O<sub>4</sub>) on the anaerobic treatment of swine wastewater (SW). The experiment was conducted in glass reactors with 200 mL of reaction volume, operating in fed-batch mode in three treatment cycles, each with 35 days. The evaluated doses of GO-Fe<sub>3</sub>O<sub>4</sub> were 3 mg L<sup>-1</sup> (1 mg gVSS<sup>-1</sup>) and 150 mg L<sup>-1</sup> (50 mg gVSS<sup>-1</sup>). In the third cycle, GO-Fe<sub>3</sub>O<sub>4</sub> (150 mg L<sup>-1</sup>) increased the biochemical methane potential by 17 %, the biogas production potential by 18 %, the methane production rate constant by 31 %, the maximum methane production rate by 32 %, and reduced the lag phase time by 25 %. Potential direct interspecies electron transfer partners are <em>Midas g 156</em> and <em>Clostridium sensu stricto 1</em> with <em>Methanobacterium beijingense</em> and <em>Methanothrix soehngenii</em>. GO-Fe<sub>3</sub>O<sub>4</sub> is a powerful and unique material for improving methane and biogas production via SW anaerobic treatment.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132551"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838826","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}
β-Galactosidases are important enzymatic tools for glycosylation, but their properties vary greatly with the source. Here, ten putative β-galactosidase genes, designated as bga1 to bga10, encoding proteins Bga1 to Bga10, were mined from an environmental metagenomic dataset comprising 119,152 sequences. Five of the encoded enzyme proteins exhibited less than 80% sequence similarity to known enzymes, but displayed conserved catalytic sites in their predicted three-dimensional models. After heterologous expression and characterization, two recombinant enzymes showed specific hydrolysis activity toward o-nitrophenyl-β-d-galactopyranoside. One of them, Bga4R, exhibited remarkable activity at pH 7.4 and 50℃, with excellent alkaline stability. Notably, Bga4R tolerated a wide range of acceptors for transglycosylation. It catalyzed galactosyl transfer to various monosaccharides and sugar alcohols, and enabling the synthesis of diverse glycosylated derivatives. This study identifies a novel GH 1 β-galactosidase as a powerful tool for glycosylation engineering, with promising potential for synthesizing galactosides valuable to food and pharmaceutical industries.
{"title":"Metagenomic exploration of novel β-galactosidases for glycosylation engineering","authors":"Jingwen Zhang , Binge Zhang , Feiyu Duan, Zehui Xuan, Tong Sun, Lili Lu","doi":"10.1016/j.biortech.2025.132546","DOIUrl":"10.1016/j.biortech.2025.132546","url":null,"abstract":"<div><div>β-Galactosidases are important enzymatic tools for glycosylation, but their properties vary greatly with the source. Here, ten putative β-galactosidase genes, designated as <em>bga</em>1 to <em>bga</em>10, encoding proteins Bga1 to Bga10, were mined from an environmental metagenomic dataset comprising 119,152 sequences. Five of the encoded enzyme proteins exhibited less than 80% sequence similarity to known enzymes, but displayed conserved catalytic sites in their predicted three-dimensional models. After heterologous expression and characterization, two recombinant enzymes showed specific hydrolysis activity toward <em>o</em>-nitrophenyl-β-<span>d</span>-galactopyranoside. One of them, Bga4R, exhibited remarkable activity at pH 7.4 and 50℃, with excellent alkaline stability. Notably, Bga4R tolerated a wide range of acceptors for transglycosylation. It catalyzed galactosyl transfer to various monosaccharides and sugar alcohols, and enabling the synthesis of diverse glycosylated derivatives. This study identifies a novel GH 1 β-galactosidase as a powerful tool for glycosylation engineering, with promising potential for synthesizing galactosides valuable to food and pharmaceutical industries.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"430 ","pages":"Article 132546"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844139","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 : 2025-04-15DOI: 10.1016/j.biortech.2025.132550
Rushuo Yang , Zhe Liu , Yongjun Liu , Zhuangzhuang Yang , Yuhang Zhang , Jie Lei , Jiaxuan Wang , Aining Zhang , Zhihua Li
In this study, high-throughput sequencing and metagenomics were used to investigate the microbial succession and functional gene dynamics during aerobic sludge granulation from activated sludge (AS) to aerobic granular sludge (AGS) to algal-bacterial granular sludge (ABGS). It was found that the settleability and pollutant removal efficiency of the sludge system increased with the sludge morphology evolution. Extracellular polymeric substances (EPS) analysis showed a rise in protein from 2.1 to 17.4 mg/gSS during stage of AGS and polysaccharides from 3.3 to 5.9 mg/gSS during stage of ABGS. Microbial community analysis revealed that the sludge evolution reduced species richness but enriched functional bacteria for nitrogen/phosphorus removal, while increasing the complexity of community structure and close interactions between species. Key genes involved in the tricarboxylic acid cycle, nitrogen/phosphorus and EPS metabolism were also upregulated. This study revealed the continuity mechanism and stage dependence of the functional transition during sludge morphology evolution.
{"title":"High-throughput community and metagenomic elucidate systematic performance variation and functional transition mechanisms during morphological evolution of aerobic sludge","authors":"Rushuo Yang , Zhe Liu , Yongjun Liu , Zhuangzhuang Yang , Yuhang Zhang , Jie Lei , Jiaxuan Wang , Aining Zhang , Zhihua Li","doi":"10.1016/j.biortech.2025.132550","DOIUrl":"10.1016/j.biortech.2025.132550","url":null,"abstract":"<div><div>In this study, high-throughput sequencing and metagenomics were used to investigate the microbial succession and functional gene dynamics during aerobic sludge granulation from activated sludge (AS) to aerobic granular sludge (AGS) to algal-bacterial granular sludge (ABGS). It was found that the settleability and pollutant removal efficiency of the sludge system increased with the sludge morphology evolution. Extracellular polymeric substances (EPS) analysis showed a rise in protein from 2.1 to 17.4 mg/gSS during stage of AGS and polysaccharides from 3.3 to 5.9 mg/gSS during stage of ABGS. Microbial community analysis revealed that the sludge evolution reduced species richness but enriched functional bacteria for nitrogen/phosphorus removal, while increasing the complexity of community structure and close interactions between species. Key genes involved in the tricarboxylic acid cycle, nitrogen/phosphorus and EPS metabolism were also upregulated. This study revealed the continuity mechanism and stage dependence of the functional transition during sludge morphology evolution.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132550"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838822","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 : 2025-04-15DOI: 10.1016/j.biortech.2025.132540
Shumin Xu , Gao Song , Xianghui Qi , Guoshi Kan , J.A.A. Sampath Jayaweer , Yingfeng An
Efficient interacting peptides or protein scaffolds can be used to achieve multi-enzymatic cascade reactions to trigger substrate channeling effect, prevent intermediate diffusion, and control the flux of metabolites. However, the limited availability of existing interactive elements hinders the broad application of the multi-enzyme assembly strategy. Here, a peptide-peptide pair (PB1C/PB2N) and a protein-peptide pair (importin/PB2C) were fused to the target protein to induce protein assembly for the first time. The newly developed interactive elements, when combined with the existing RIDD/RIAD pair, can more efficiently achieve multi-enzymatic cascade reactions. The indigo synthesis pathway was optimized through cascade biocatalysis based on these interactive elements. As a result, compared with the co-expression of multiple enzymes, the interaction element-based cascade biocatalysis increased the yield of indigo by twofold. Our results demonstrate the potential of PB1C/PB2N and importin/PB2C scaffold systems as tools for enzyme assembly to control metabolic flux and increase the efficiency of biosynthetic pathways.
{"title":"Engineered interaction elements enable enhanced multi-enzyme assembly and cascade biocatalysis for indigo synthesis","authors":"Shumin Xu , Gao Song , Xianghui Qi , Guoshi Kan , J.A.A. Sampath Jayaweer , Yingfeng An","doi":"10.1016/j.biortech.2025.132540","DOIUrl":"10.1016/j.biortech.2025.132540","url":null,"abstract":"<div><div>Efficient interacting peptides or protein scaffolds can be used to achieve multi-enzymatic cascade reactions to trigger substrate channeling effect, prevent intermediate diffusion, and control the flux of metabolites. However, the limited availability of existing interactive elements hinders the broad application of the multi-enzyme assembly strategy. Here, a peptide-peptide pair (PB1C/PB2N) and a protein-peptide pair (importin/PB2C) were fused to the target protein to induce protein assembly for the first time. The newly developed interactive elements, when combined with the existing RIDD/RIAD pair, can more efficiently achieve multi-enzymatic cascade reactions. The indigo synthesis pathway was optimized through cascade biocatalysis based on these interactive elements. As a result, compared with the co-expression of multiple enzymes, the interaction element-based cascade biocatalysis increased the yield of indigo by twofold. Our results demonstrate the potential of PB1C/PB2N and importin/PB2C scaffold systems as tools for enzyme assembly to control metabolic flux and increase the efficiency of biosynthetic pathways.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132540"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833929","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 : 2025-04-15DOI: 10.1016/j.biortech.2025.132545
Qing Zhang , Jiao Meng , Qingwen Tian , Lili Zhang , Jing Shen , Yonghao Ni , Zhiguo Wang
The recyclability of lactic acid/choline chloride deep eutectic solvent (DES) in lignocellulose fractionation remains challenging. This study demonstrates that DES reuse reduces delignification efficiency, with a residual lignin content of 9.64% after three cycles, resulting in incomplete fiber separation. The molecular weight of dissolved lignin increased, and 2D HSQC NMR revealed reduced β-O-4 cleavage. Accumulated dissolved hemicellulose and its degradation products (e.g., acetic acid, furfural) altered DES properties, increasing viscosity and reducing hydrogen bond basicity, which hindered mass transfer, lignin-carbohydrate complex dissociation, and lignin depolymerization. To address these limitations, activated carbon adsorption (boosting delignification degree to 77%, near fresh DES at 80%) and prehydrolysis (achieving 82% after three cycles vs. 90% for fresh DES) are proposed to remove hemicellulose and its byproducts, minimizing their impact on recycled DES. This study demonstrates the recyclability of DES and proposes two strategies that significantly improve it, ensuring sustainable and efficient biomass fractionation.
{"title":"Effect of hemicellulose and its-derived products on the recycling and efficiency of biomass fractionation using lactic acid/choline chloride (DES)","authors":"Qing Zhang , Jiao Meng , Qingwen Tian , Lili Zhang , Jing Shen , Yonghao Ni , Zhiguo Wang","doi":"10.1016/j.biortech.2025.132545","DOIUrl":"10.1016/j.biortech.2025.132545","url":null,"abstract":"<div><div>The recyclability of lactic acid/choline chloride deep eutectic solvent (DES) in lignocellulose fractionation remains challenging. This study demonstrates that DES reuse reduces delignification efficiency, with a residual lignin content of 9.64% after three cycles, resulting in incomplete fiber separation. The molecular weight of dissolved lignin increased, and 2D HSQC NMR revealed reduced β-O-4 cleavage. Accumulated dissolved hemicellulose and its degradation products (e.g., acetic acid, furfural) altered DES properties, increasing viscosity and reducing hydrogen bond basicity, which hindered mass transfer, lignin-carbohydrate complex dissociation, and lignin depolymerization. To address these limitations, activated carbon adsorption (boosting delignification degree to 77%, near fresh DES at 80%) and prehydrolysis (achieving 82% after three cycles vs. 90% for fresh DES) are proposed to remove hemicellulose and its byproducts, minimizing their impact on recycled DES. This study demonstrates the recyclability of DES and proposes two strategies that significantly improve it, ensuring sustainable and efficient biomass fractionation.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"430 ","pages":"Article 132545"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844138","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 : 2025-04-15DOI: 10.1016/j.biortech.2025.132547
Kira J. Picknell , Nature Poddar , Janice I. McCauley , Alexandre V. Chaves , Peter J. Ralph
Microalgae offer an innovative solution for utilizing industrial waste to produce sustainable ruminant feed. With strong carbon capture capabilities, they play a vital role in biological carbon capture and utilization. Advances in biotechnology enable the use of industrial waste streams, offering a pathway to reducing carbon emissions and cultivation costs. Extensive research highlights microalgae’s nutritional and anti-methanogenic benefits for ruminants, yet they remain commercially unutilized in feed. To address cultivation limitations, this review explores advancements in algae carbon capture biotechnology and proposes brewery waste to support algae cultivation. In addition, the challenges and bottlenecks that remain to be overcome for future commercial translation of this strategy are presented. This review establishes a theoretical solution for integrating microalgae into high-emission industries like breweries and utilization of algae biomass to reduce agricultural emissions.
{"title":"Whole cell microalgae: Potential to transform industry waste into sustainable ruminant feed","authors":"Kira J. Picknell , Nature Poddar , Janice I. McCauley , Alexandre V. Chaves , Peter J. Ralph","doi":"10.1016/j.biortech.2025.132547","DOIUrl":"10.1016/j.biortech.2025.132547","url":null,"abstract":"<div><div>Microalgae offer an innovative solution for utilizing industrial waste to produce sustainable ruminant feed. With strong carbon capture capabilities, they play a vital role in biological carbon capture and utilization. Advances in biotechnology enable the use of industrial waste streams, offering a pathway to reducing carbon emissions and cultivation costs. Extensive research highlights microalgae’s nutritional and anti-methanogenic benefits for ruminants, yet they remain commercially unutilized in feed. To address cultivation limitations, this review explores advancements in algae carbon capture biotechnology and proposes brewery waste to support algae cultivation. In addition, the challenges and bottlenecks that remain to be overcome for future commercial translation of this strategy are presented. This review establishes a theoretical solution for integrating microalgae into high-emission industries like breweries and utilization of algae biomass to reduce agricultural emissions.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"430 ","pages":"Article 132547"},"PeriodicalIF":9.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143848266","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}
This review explores the hydrothermal carbonization (HTC) of microalgae through a comprehensive evaluation of the influence of process parameters on the resultant products. The findings revealed that HTC of microalgae takes place at lower temperatures (170 – 250 °C) compared to lignocellulosic feedstocks, and the resulting hydrochar and hydrolysate have a higher N-content. Additionally, secondary char production varies based on reaction conditions, with yields between 4 % and 35 %. The interaction between carbohydrates and nitrogenous compounds in the hydrolysate at varying reaction severities was discussed, underlining the extent of nitrogen fixation in the hydrochar and total organic C-content of up to 26.8 g L-1. The article also suggests strategies to improve hydrochar properties by assessing different technical strategies and emphasizing future direction research. In summary, this review underscores the potential of microalgal HTC as a sustainable approach for applications in energy and environmental applications via process optimization and technological upgradation.
{"title":"Synthetic coalification of microalgae through hydrothermal carbonization: strategies for enhanced hydrochar characteristics and technological advancements","authors":"Joydeepa Taran , Rajarshi Bhar , Hema Jha , Saikat Kumar Kuila , Biswajit Samal , Ranjan Pradhan , Brajesh Kumar Dubey","doi":"10.1016/j.biortech.2025.132542","DOIUrl":"10.1016/j.biortech.2025.132542","url":null,"abstract":"<div><div>This review explores the hydrothermal carbonization (HTC) of microalgae through a comprehensive evaluation of the influence of process parameters on the resultant products. The findings revealed that HTC of microalgae takes place at lower temperatures (170 – 250 °C) compared to lignocellulosic feedstocks, and the resulting hydrochar and hydrolysate have a higher N-content. Additionally, secondary char production varies based on reaction conditions, with yields between 4 % and 35 %. The interaction between carbohydrates and nitrogenous compounds in the hydrolysate at varying reaction severities was discussed, underlining the extent of nitrogen fixation in the hydrochar and total organic C-content of up to 26.8 g L<sup>-1</sup>. The article also suggests strategies to improve hydrochar properties by assessing different technical strategies and emphasizing future direction research. In summary, this review underscores the potential of microalgal HTC as a sustainable approach for applications in energy and environmental applications via process optimization and technological upgradation.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132542"},"PeriodicalIF":9.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838817","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 : 2025-04-14DOI: 10.1016/j.biortech.2025.132533
Dun Guo , Lei Yang , Hao-Qi Lu , Yu-Chao Wang , Hong-Yan Meng , Pan Liang , Shen Cui , Zhang-Wei He , Jun Lan , Yong-Xiang Ren
Optimizing electron shuttles and revealing their mediating mechanisms are crucial for enhancing the ammonium (NH4+-N) oxidation coupled with Fe (III) reduction. In this study, anthraquinone-2,6-disulfonate (AQDs), riboflavin (RF), and humic acid (HA) were optimized in batch tests. The optimal dosages of 6, 2, and 8 mg/L for AQDs, RF, and HA resulted in average maximum NH4+-N removal of 80.2 %, 88.5 %, and 99.2 %, with 91.4 %, 88.5 %, and 74.7 % of the removed NH4+-N converted to nitrate, respectively. In addition, an enhanced extracellular electron transfer was also observed, including an enlarged current, diversified REDOX pathway, and reduced resistance. Outperformed AQDs in nitrogen removal and microbial activity, HA and RF were selected for the subsequent 100-day long-term investigation. During this stage, excess influent Fe tended to be stored as insoluble coatings on the sludge surface, while RF and HA facilitated its use to compensate for the reduced influent Fe3+. Meanwhile, they led to an increase in iron-reducing (Comamonas) and NH4+-N oxidizing bacteria (Nitropsira and Planctomycetes), as well as improvements in electrochemical characteristics and microbial activity. Moreover, microbial N and Fe metabolic potential were efficiently enhanced. Consequently, NH4+-N and TN removal rates were obviously increased to approximately 90 % and 40 %, respectively. The addition of electron shuttles led to long-term improvements in extracellular mass transfer and microbial metabolism, which contributed more than bridging the extracellular electron transfer. These results deepened the understanding of the effect of electron shuttles on Feammox.
{"title":"Enhancing Feammox efficiency through riboflavin and humic acid: Nitrogen and iron transformation, energy metabolism, and microbial response","authors":"Dun Guo , Lei Yang , Hao-Qi Lu , Yu-Chao Wang , Hong-Yan Meng , Pan Liang , Shen Cui , Zhang-Wei He , Jun Lan , Yong-Xiang Ren","doi":"10.1016/j.biortech.2025.132533","DOIUrl":"10.1016/j.biortech.2025.132533","url":null,"abstract":"<div><div>Optimizing electron shuttles and revealing their mediating mechanisms are crucial for enhancing the ammonium (NH<sub>4</sub><sup>+</sup>-N) oxidation coupled with Fe (III) reduction. In this study, anthraquinone-2,6-disulfonate (AQDs), riboflavin (RF), and humic acid (HA) were optimized in batch tests. The optimal dosages of 6, 2, and 8 mg/L for AQDs, RF, and HA resulted in average maximum NH<sub>4</sub><sup>+</sup>-N removal of 80.2 %, 88.5 %, and 99.2 %, with 91.4 %, 88.5 %, and 74.7 % of the removed NH<sub>4</sub><sup>+</sup>-N converted to nitrate, respectively. In addition, an enhanced extracellular electron transfer was also observed, including an enlarged current, diversified REDOX pathway, and reduced resistance. Outperformed AQDs in nitrogen removal and microbial activity, HA and RF were selected for the subsequent 100-day long-term investigation. During this stage, excess influent Fe tended to be stored as insoluble coatings on the sludge surface, while RF and HA facilitated its use to compensate for the reduced influent Fe<sup>3+</sup>. Meanwhile, they led to an increase in iron-reducing (<em>Comamonas</em>) and NH<sub>4</sub><sup>+</sup>-N oxidizing bacteria (<em>Nitropsira</em> and <em>Planctomycetes</em>), as well as improvements in electrochemical characteristics and microbial activity. Moreover, microbial N and Fe metabolic potential were efficiently enhanced. Consequently, NH<sub>4</sub><sup>+</sup>-N and TN removal rates were obviously increased to approximately 90 % and 40 %, respectively. The addition of electron shuttles led to long-term improvements in extracellular mass transfer and microbial metabolism, which contributed more than bridging the extracellular electron transfer. These results deepened the understanding of the effect of electron shuttles on Feammox.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132533"},"PeriodicalIF":9.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833922","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}
Fermentation technology presents promising opportunities for food waste valorization. Pomegranate peel (PP), a food by-product, has potential applications in fermented feed. This study examined the effects of a 6% dry PP additive on the ensiling characteristics, antioxidant activity, metabolites, bacterial community, and in vitro ruminal fermentation, methane (CH4) emission of corn silage ensiled for 7 days and 60 days using microbiome and metabolome analyses. PP-treated silage inhibited (P < 0.05) protein degradation by reducing ammonia nitrogen and non-protein nitrogen concentrations during ensiling. The PP additive increased (P < 0.05) water-soluble carbohydrate content and reduced ethanol production in corn silage. Lactiplantibacillus dominated PP-treated silage at the initial ensiling stage, while Levilactobacillus prevailed at the final stage. Notably, the PP additive exhibited strong antioxidant activity by modulating antioxidant enzymes and flavonoid biosynthesis mediated by key metabolites (epigallocatechin and catechin). Correlation analysis identified Lactiplantibacillus, Citrobacter, Phytobacter and Burkholderia as key microbes in the production of antioxidant metabolites and enzymes in PP-treated silage. Additionally, PP supplementation reduced (P < 0.05) in vitro ruminal CH4 and nitrogen losses, while decreasing dry matter (DM) digestibility in corn silage. In summary, PP-treated corn silage enhanced antioxidant properties and reduced the nitrogen losses and in vitro ruminal CH4 emissions, but lowered DM digestibility. Thus, PP can be recommended as a silage additive, though the dry PP level should be lower than that used in this study.
{"title":"From waste to value: Multi-omics reveal pomegranate peel addition improves corn silage antioxidant activity and reduces methane and nitrogen losses","authors":"Xia Zhang, Huixian Zhang, Dongcai Wang, Yuanqing Zhang","doi":"10.1016/j.biortech.2025.132544","DOIUrl":"10.1016/j.biortech.2025.132544","url":null,"abstract":"<div><div>Fermentation technology presents promising opportunities for food waste valorization. Pomegranate peel (<strong>PP</strong>), a food by-product, has potential applications in fermented feed. This study examined the effects of a 6% dry PP additive on the ensiling characteristics, antioxidant activity, metabolites, bacterial community, and <em>in vitro</em> ruminal fermentation, methane (CH<sub>4</sub>) emission of corn silage ensiled for 7 days and 60 days using microbiome and metabolome analyses. PP-treated silage inhibited (<em>P</em> < 0.05) protein degradation by reducing ammonia nitrogen and non-protein nitrogen concentrations during ensiling. The PP additive increased (<em>P</em> < 0.05) water-soluble carbohydrate content and reduced ethanol production in corn silage. <em>Lactiplantibacillus</em> dominated PP-treated silage at the initial ensiling stage, while <em>Levilactobacillus</em> prevailed at the final stage<em>.</em> Notably, the PP additive exhibited strong antioxidant activity by modulating antioxidant enzymes and flavonoid biosynthesis mediated by key metabolites (epigallocatechin and catechin). Correlation analysis identified <em>Lactiplantibacillus</em>, <em>Citrobacter</em>, <em>Phytobacter</em> and <em>Burkholderia</em> as key microbes in the production of antioxidant metabolites and enzymes in PP-treated silage. Additionally, PP supplementation reduced (<em>P</em> < 0.05) <em>in vitro</em> ruminal CH<sub>4</sub> and nitrogen losses, while decreasing dry matter (DM) digestibility in corn silage. In summary, PP-treated corn silage enhanced antioxidant properties and reduced the nitrogen losses and <em>in vitro</em> ruminal CH<sub>4</sub> emissions, but lowered DM digestibility. Thus, PP can be recommended as a silage additive, though the dry PP level should be lower than that used in this study.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132544"},"PeriodicalIF":9.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833925","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 : 2025-04-14DOI: 10.1016/j.biortech.2025.132531
Jun Gao , Qi Mang , Quanjie Li , Yi Sun , Gangchun Xu
Intensive aquaculture’s excessive nitrogen, phosphorus, and methane emissions caused environmental degradation. This study explored how algae-bacteria symbiotic systems (ABSS) enhanced water purification by regulating element cycles. We established a Chlorella pyrenoidosa-Bacillus subtilis symbiotic system. At a 1:1 bacteria-to-algae ratio, chlorophyll a and cell dry weight were highest. C. pyrenoidosa supplied organic acids, carbohydrates, and amino acids to B. subtilis, which reciprocated with amino acids, purines, and vitamins. ABSS significantly reduced total nitrogen, ammonia nitrogen (NH4+-N), nitrite (NO2−-N), nitrate (NO3−-N), phosphate (PO43−-P), total phosphorous, dissolved organic carbon, and chemical oxygen demand in aquaculture water. It reshaped microbial communities and enriched key genus (Limnohabitans, Planktophila, Polaromonas, Methylocystis) and upregulating genes linked to organic phosphate mineralization, methane oxidation, and nitrate reduction. These changes strengthened nitrogen-phosphorus-methane cycle coupling, boosting water purification. ABSS offers an eco-engineering solution for aquaculture pollution by optimizing microbial interactions and nutrient cycling.
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