Pub Date : 2025-04-03DOI: 10.1016/j.biortech.2025.132481
Farokh Laqa Kakar , Hussain Aqeel , Frances Okoye , Elsayed Elbeshbishy , Steven N. Liss
This study investigated a novel thermal-hydrolysis combined with a vacuum fermentation system for high-grade volatile fatty acids (VFA) recovery, and the corresponding changes in the microbial community. Four systems with and without hydrothermal pre-treatment (HTP) and vacuum were mobilized; results revealed that integration of HTP with vacuum has the highest potential in terms of VFA recovery, sludge disintegration, and solid reduction. HTP and vacuum fermentation systems were associated with the highest COD solubilization (45 %), and VFA yield (0.32 g COD/g VSS added). Vacuum fermenters with and without pre-treatment have the highest specific denitrification rates of 7.6 and 7.2 mg NO3-N/g VSS.h, respectively, compared to all other samples and control (acetate). Changes brought about by vacuum fermentation included a shift in the microbial community toward enriching fermenters, mainly Caprothermobacteria and Thermotagea, responsible for VFA production.
{"title":"Microbial shifts and VFA production in the optimization of anaerobic digestion by thermal hydrolysis coupled with vacuum fermentation","authors":"Farokh Laqa Kakar , Hussain Aqeel , Frances Okoye , Elsayed Elbeshbishy , Steven N. Liss","doi":"10.1016/j.biortech.2025.132481","DOIUrl":"10.1016/j.biortech.2025.132481","url":null,"abstract":"<div><div>This study investigated a novel thermal-hydrolysis combined with a vacuum fermentation system for high-grade volatile fatty acids (VFA) recovery, and the corresponding changes in the microbial community. Four systems with and without hydrothermal pre-treatment (HTP) and vacuum were mobilized; results revealed that integration of HTP with vacuum has the highest potential in terms of VFA recovery, sludge disintegration, and solid reduction. HTP and vacuum fermentation systems were associated with the highest COD solubilization (45 %), and VFA yield (0.32 g COD/g VSS added). Vacuum fermenters with and without pre-treatment have the highest specific denitrification rates of 7.6 and 7.2 mg NO<sub>3</sub>-N/g VSS.h, respectively, compared to all other samples and control (acetate). Changes brought about by vacuum fermentation included a shift in the microbial community toward enriching fermenters, mainly <em>Caprothermobacteria</em> and <em>Thermotagea,</em> responsible for VFA production<em>.</em></div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132481"},"PeriodicalIF":9.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-03DOI: 10.1016/j.biortech.2025.132485
Sali Khair Biek , Leadin S. Khudur , Matthew Askeland , Jacob Jones , Kriushnapriya Sundararajan , Shivaram Lakshminarayanan , Andrew S. Ball
Rising concerns about solid waste management globally necessitate the adoption of sustainable practices, particularly in dealing with organic waste, which constitutes a significant portion of municipal solid waste (MSW). Composting is an effective waste management strategy that can reduce both the environmental impact and greenhouse gas emissions of organic wastes, while producing valuable organic material (compost) for soil enhancement. However, the presence of persistent contaminants such as per- and polyfluoroalkyl substances (PFAS) in compost poses environmental and human health risks, challenging the sustainable management of organic wastes. This study investigates the fate of 33 PFAS compounds in two composting systems—windrow and in-vessel—focusing on the transformation and persistence of these compounds through the composting process, with the aim of collecting information which will support the identification of strategies to mitigate PFAS contamination in composting practices. The findings indicate significant reductions in total PFAS concentrations after composting, with reductions of 88.3% and 86.3% in the windrow and in-vessel systems, respectively. Notably, certain PFAS compounds, such as PFBS, appeared after composting, while PFPeA, became undetectable, suggesting potential leaching or transformation. Across both leachate and dust samples, PFAS concentrations were relatively low, with only a few compounds detected in each matrix. The final compost products met Australia’s proposed NEMP 3.0 guidelines. However, considering the variation in PFAS content within similar categories of waste (feedstock), compliance with regulatory limits may vary. These results highlight the need for continued research into PFAS behaviour during composting and the development of best practices to mitigate contamination risks.
{"title":"Fate of per- and polyfluoroalkyl substances through commercial composting facilities","authors":"Sali Khair Biek , Leadin S. Khudur , Matthew Askeland , Jacob Jones , Kriushnapriya Sundararajan , Shivaram Lakshminarayanan , Andrew S. Ball","doi":"10.1016/j.biortech.2025.132485","DOIUrl":"10.1016/j.biortech.2025.132485","url":null,"abstract":"<div><div>Rising concerns about solid waste management globally necessitate the adoption of sustainable practices, particularly in dealing with organic waste, which constitutes a significant portion of municipal solid waste (MSW). Composting is an effective waste management strategy that can reduce both the environmental impact and greenhouse gas emissions of organic wastes, while producing valuable organic material (compost) for soil enhancement. However, the presence of persistent contaminants such as per- and polyfluoroalkyl substances (PFAS) in compost poses environmental and human health risks, challenging the sustainable management of organic wastes. This study investigates the fate of 33 PFAS compounds in two composting systems—windrow and in-vessel—focusing on the transformation and persistence of these compounds through the composting process, with the aim of collecting information which will support the identification of strategies to mitigate PFAS contamination in composting practices. The findings indicate significant reductions in total PFAS concentrations after composting, with reductions of 88.3% and 86.3% in the windrow and in-vessel systems, respectively. Notably, certain PFAS compounds, such as PFBS, appeared after composting, while PFPeA, became undetectable, suggesting potential leaching or transformation. Across both leachate and dust samples, PFAS concentrations were relatively low, with only a few compounds detected in each matrix. The final compost products met Australia’s proposed NEMP 3.0 guidelines. However, considering the variation in PFAS content within similar categories of waste (feedstock), compliance with regulatory limits may vary. These results highlight the need for continued research into PFAS behaviour during composting and the development of best practices to mitigate contamination risks.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132485"},"PeriodicalIF":9.7,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-02DOI: 10.1016/j.biortech.2025.132453
Gina Welsing , Birger Wolter , Greta E.K. Kleinert , Frederike Göttsch , Werner Besenmatter , Rui Xue , Alessandra Mauri , Dominik Steffens , Sebastian Köbbing , Weiliang Dong , Min Jiang , Uwe T. Bornscheuer , Ren Wei , Till Tiso , Lars M. Blank
{"title":"Corrigendum to “Two-step biocatalytic conversion of post-consumer polyethylene terephthalate into value-added products facilitated by genetic and bioprocess engineering” [Bioresour. Technol. 417 (2025) 131837]","authors":"Gina Welsing , Birger Wolter , Greta E.K. Kleinert , Frederike Göttsch , Werner Besenmatter , Rui Xue , Alessandra Mauri , Dominik Steffens , Sebastian Köbbing , Weiliang Dong , Min Jiang , Uwe T. Bornscheuer , Ren Wei , Till Tiso , Lars M. Blank","doi":"10.1016/j.biortech.2025.132453","DOIUrl":"10.1016/j.biortech.2025.132453","url":null,"abstract":"","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132453"},"PeriodicalIF":9.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143748239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-02DOI: 10.1016/j.biortech.2025.132463
Ayush Agarwal , Laura Torrent , Julian Indlekofer , Hossein Madi , Lucy P. Culleton , Serge M.A. Biollaz , Christian Ludwig
Siloxanes in biogas pose significant challenges to energy systems, leading to operational inefficiencies and increased maintenance costs. This study advances the liquid quench sampling system (LQ) for accurate quantification of siloxanes using gas chromatography hyphenated with inductively coupled plasma mass spectrometry (GC-ICP-MS). The LQ demonstrated a capture efficiency exceeding 94 % over a broad concentration range, with sample stability tests indicating < 10 % analyte loss over four weeks. A Round Robin Test with nine independent laboratories validated the method’s reliability. Calibration with liquid standards is demonstrated, eliminating complications associated with gaseous standards. On-site sampling with centralized analysis makes the method feasible for facilities lacking advanced instrumentation. By accurately quantifying siloxanes, this approach supports optimization of gas cleaning systems to extend equipment life. This LQ-GC-ICP-MS method enables practical sampling and simplified quantification for effective siloxane monitoring to enhance biogas utilization.
{"title":"From proof to practice − Sampling and analysis for simplified quantification of siloxanes in biogas","authors":"Ayush Agarwal , Laura Torrent , Julian Indlekofer , Hossein Madi , Lucy P. Culleton , Serge M.A. Biollaz , Christian Ludwig","doi":"10.1016/j.biortech.2025.132463","DOIUrl":"10.1016/j.biortech.2025.132463","url":null,"abstract":"<div><div>Siloxanes in biogas pose significant challenges to energy systems, leading to operational inefficiencies and increased maintenance costs. This study advances the liquid quench sampling system (LQ) for accurate quantification of siloxanes using gas chromatography hyphenated with inductively coupled plasma mass spectrometry (GC-ICP-MS). The LQ demonstrated a capture efficiency exceeding 94 % over a broad concentration range, with sample stability tests indicating < 10 % analyte loss over four weeks. A Round Robin Test with nine independent laboratories validated the method’s reliability. Calibration with liquid standards is demonstrated, eliminating complications associated with gaseous standards. On-site sampling with centralized analysis makes the method feasible for facilities lacking advanced instrumentation. By accurately quantifying siloxanes, this approach supports optimization of gas cleaning systems to extend equipment life. This LQ-GC-ICP-MS method enables practical sampling and simplified quantification for effective siloxane monitoring to enhance biogas utilization.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"429 ","pages":"Article 132463"},"PeriodicalIF":9.7,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143787446","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 : 2025-03-31DOI: 10.1016/j.biortech.2025.132470
Gowtham Balasundaram , Pallavi Gahlot , Rendra Hakim Hafyan , Vinay Kumar Tyagi , Siddharth Gadkari , Ashish Sahu , Bill Barber , Pravin K. Mutiyar , A.A. Kazmi , Harald Kleiven
This study assessed the potential of thermal hydrolysis process (THP) combined with anaerobic digestion (AD) for high solids sewage sludge treatment across various hydraulic retention times (HRTs). Optimal performance was achieved at a 10-day HRT (6 kg VS/m3·day), yielding 408 L CH4/kg VS added and 54 % volatile solids (VS) removal under THP conditions of 160 °C, 30 min, and 6 bar pressure. Microbial analysis revealed predominant acetoclastic and hydrogenotrophic methanogens. Four scenarios were designed and analyzed for environmental and economic performance: Scenario 1 (conventional AD-CHP), Scenario 2 (conventional AD-BioCNG), Scenario 3 (THP AD-BioCNG), and Scenario 4 (THP AD-CHP). The results showed that scenarios with CHP integration achieved better environmental performance by generating sufficient energy to meet demand, with energy consumption as a key factor. Notably, scenario 4 had the lowest global warming potential (GWP) at −0.0185 kg CO2-eq, outperforming conventional AD (Scenario 1) with CHP, which had a GWP of −0.00232 kg CO2-eq. However, profitability analysis showed that Scenario 3 was the most economically viable, with a net present value (NPV) of $4.3 million, an internal rate of return (IRR) of 10.21 %, and a 17-year payback period. Although it had higher capital ($58 million) and operational costs ($12.5 million/year) than Scenario 4 ($45 million and $8.6 million/year), its greater biomethane yield resulted in higher revenue ($20.7 million/year), making it the most profitable option. While Scenario 4 offered the best environmental benefits, Scenario 3 emerged as the most financially sustainable choice. These findings highlight the environmental and economic advantage of utilizing THP-AD process over conventional AD, suggesting that THP-AD optimizes methane production, solids reduction, and environmental impact, making the Bio CNG pathway a sustainable and economically viable option.
{"title":"Anaerobic digestion of thermal hydrolysis pretreated sludge: Process performance, metagenomic analysis, techno-economic and life cycle assessment","authors":"Gowtham Balasundaram , Pallavi Gahlot , Rendra Hakim Hafyan , Vinay Kumar Tyagi , Siddharth Gadkari , Ashish Sahu , Bill Barber , Pravin K. Mutiyar , A.A. Kazmi , Harald Kleiven","doi":"10.1016/j.biortech.2025.132470","DOIUrl":"10.1016/j.biortech.2025.132470","url":null,"abstract":"<div><div>This study assessed the potential of thermal hydrolysis process (THP) combined with anaerobic digestion (AD) for high solids sewage sludge treatment across various hydraulic retention times (HRTs). Optimal performance was achieved at a 10-day HRT (6 kg VS/m<sup>3</sup>·day), yielding 408 L CH<sub>4</sub>/kg VS added and 54 % volatile solids (VS) removal under THP conditions of 160 °C, 30 min, and 6 bar pressure. Microbial analysis revealed predominant acetoclastic and hydrogenotrophic methanogens. Four scenarios were designed and analyzed for environmental and economic performance: Scenario 1 (conventional AD-CHP), Scenario 2 (conventional AD-BioCNG), Scenario 3 (THP AD-BioCNG), and Scenario 4 (THP AD-CHP). The results showed that scenarios with CHP integration achieved better environmental performance by generating sufficient energy to meet demand, with energy consumption as a key factor. Notably, scenario 4 had the lowest global warming potential (GWP) at −0.0185 kg CO<sub>2</sub>-eq, outperforming conventional AD (Scenario 1) with CHP, which had a GWP of −0.00232 kg CO<sub>2</sub>-eq. However, profitability analysis showed that Scenario 3 was the most economically viable, with a net present value (NPV) of $4.3 million, an internal rate of return (IRR) of 10.21 %, and a 17-year payback period. Although it had higher capital ($58 million) and operational costs ($12.5 million/year) than Scenario 4 ($45 million and $8.6 million/year), its greater biomethane yield resulted in higher revenue ($20.7 million/year), making it the most profitable option. While Scenario 4 offered the best environmental benefits, Scenario 3 emerged as the most financially sustainable choice. These findings highlight the environmental and economic advantage of utilizing THP-AD process over conventional AD, suggesting that THP-AD optimizes methane production, solids reduction, and environmental impact, making the Bio CNG pathway a sustainable and economically viable option.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132470"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768994","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 : 2025-03-31DOI: 10.1016/j.biortech.2025.132474
Xiaoting Xiong , Jingyi Jiang , Hanbo Yu , Yanxiao Wei , Jing Chen , Zhihua Liu , Haoshuai Ji , Hong Chen , Eli Hendrik Sanjaya , Lvzhou Wu
To maintain the long-term stability and efficiency of the partial nitritation/anammox (PN/A) process, a novel partition bioreactor featuring a uniquely sieve plate was developed to improve the airlift inner-circulation. The bioreactor achieved startup within 38 days, effectively handling influent containing 150 mg-N/L ammonium nitrogen and 50 mg-N/L nitrite. By reducing hydraulic retention time, nitrogen loading rate was escalated to 0.60 kg-N/m3/d, maintaining over 80 % nitrogen removal. Additionally, fluctuations in nitrite-oxidizing bacteria (NOB) were automatically controlled through dissolved oxygen (DO) partitioning. Moreover, the average granules size expanded from 85 μm to 338 μm by day 127, coinciding with robust anammox activity reaching 1.02 ± 0.05 g-N/g-VSS/d by day 179. The results demonstrate that the bioreactor effectively enhanced the enrichment of functional bacteria, enabled spatial distribution of DO, promoted NOB self-regulation and sludge granulation. This approach provides an efficient solution for rapid granulation while maintaining stable performance in the PN/A process.
{"title":"Achieving rapid granulation and long-term stability of partial nitritation /anammox process by uniquely configured airlift inner-circulation partition bioreactor","authors":"Xiaoting Xiong , Jingyi Jiang , Hanbo Yu , Yanxiao Wei , Jing Chen , Zhihua Liu , Haoshuai Ji , Hong Chen , Eli Hendrik Sanjaya , Lvzhou Wu","doi":"10.1016/j.biortech.2025.132474","DOIUrl":"10.1016/j.biortech.2025.132474","url":null,"abstract":"<div><div>To maintain the long-term stability and efficiency of the partial nitritation/anammox (PN/A) process, a novel partition bioreactor featuring a uniquely sieve plate was developed to improve the airlift inner-circulation. The bioreactor achieved startup within 38 days, effectively handling influent containing 150 mg-N/L ammonium nitrogen and 50 mg-N/L nitrite. By reducing hydraulic retention time, nitrogen loading rate was escalated to 0.60 kg-N/m<sup>3</sup>/d, maintaining over 80 % nitrogen removal. Additionally, fluctuations in nitrite-oxidizing bacteria (NOB) were automatically controlled through dissolved oxygen (DO) partitioning. Moreover, the average granules size expanded from 85 μm to 338 μm by day 127, coinciding with robust anammox activity reaching 1.02 ± 0.05 g-N/g-VSS/d by day 179. The results demonstrate that the bioreactor effectively enhanced the enrichment of functional bacteria, enabled spatial distribution of DO, promoted NOB self-regulation and sludge granulation. This approach provides an efficient solution for rapid granulation while maintaining stable performance in the PN/A process.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132474"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760221","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 : 2025-03-31DOI: 10.1016/j.biortech.2025.132473
Wei Jiang , Haoyi Wei , Zhi Xu , Jianxiong Kang , Songlin Wang , Dongqi Liu , Yongzheng Ren , Huu Hao Ngo , Wenshan Guo , Yuanyao Ye
The anaerobic treatment of sulfur-laden organic wastewater is common; however, competition between sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) can result in low removal efficiencies and unstable systems. Photosynthetic bacteria, capable of oxidizing reduced sulfides, can alleviate sulfide toxicity to microorganisms, thereby enhancing sulfate removal. This study compared the performance of anaerobic reactors under identical organic loads but with varying light conditions and different carbon-to-sulfur (C/S) ratios. The illuminated reactors outperformed the non-illuminated ones, achieving sulfate removal rates exceeding 85% when the light wavelength was optimized. Sludge analysis revealed that the illuminated group had larger particle sizes and higher protein and polysaccharide contents compared to the non-illuminated group. These findings suggest that light exposure enhances the removal of sulfate and organic matter, mitigates competitive inhibition, and promotes synergistic interactions among microbial populations, offering valuable insights for treating sulfate-rich wastewater using photosynthetic bacteria.
{"title":"Lighting promotes sulfate removal and improves microbial community stability in upflow anaerobic sludge bed reactors under low ratio of chemical oxygen demand to sulfate","authors":"Wei Jiang , Haoyi Wei , Zhi Xu , Jianxiong Kang , Songlin Wang , Dongqi Liu , Yongzheng Ren , Huu Hao Ngo , Wenshan Guo , Yuanyao Ye","doi":"10.1016/j.biortech.2025.132473","DOIUrl":"10.1016/j.biortech.2025.132473","url":null,"abstract":"<div><div>The anaerobic treatment of sulfur-laden organic wastewater is common; however, competition between sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) can result in low removal efficiencies and unstable systems. Photosynthetic bacteria, capable of oxidizing reduced sulfides, can alleviate sulfide toxicity to microorganisms, thereby enhancing sulfate removal. This study compared the performance of anaerobic reactors under identical organic loads but with varying light conditions and different carbon-to-sulfur (C/S) ratios. The illuminated reactors outperformed the non-illuminated ones, achieving sulfate removal rates exceeding 85% when the light wavelength was optimized. Sludge analysis revealed that the illuminated group had larger particle sizes and higher protein and polysaccharide contents compared to the non-illuminated group. These findings suggest that light exposure enhances the removal of sulfate and organic matter, mitigates competitive inhibition, and promotes synergistic interactions among microbial populations, offering valuable insights for treating sulfate-rich wastewater using photosynthetic bacteria.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132473"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760222","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 : 2025-03-31DOI: 10.1016/j.biortech.2025.132471
Xingwang Ma , Kang Yan , Yuwei Zhang , Xiaoyu Xie , Shujie Zou , Yuanyuan Sha , Rui Zhai , Zhaoxian Xu , Mingjie Jin
Optically pure lactic acid is essential for poly(lactic acid) manufacturing, nonetheless, most wild-type lactic acid bacteria inherently produce D-/L- mixed lactic acid. In this study, an elaborate system was designed for developing d-lactic acid producing mutants from a wild-type D-/L- lactic acid producing Lactobacillus by combining chemical mutagenesis with ethyl methane sulfonate as the mutagen and high throughput screening with a l-lactate dehydrogenase based biosensor. Mechanistic analysis revealed that the loss of l-lactate dehydrogenase activity via C → T transitions in the corresponding gene is responsible for generation of d-lactic acid producing mutants. The obtained d-lactic acid producing mutant exhibited excellent performance in different types of lignocellulosic hydrolysates and produced 128.3 g/L d-lactic acid from corn stover hydrolysate in 3-L bioreactor fermentation, with optical purity higher than 98 %. In conclusion, this study provided a practical framework for obtaining optically pure lactic acid producers without genetic engineering operations, advancing the sustainable production of cellulosic bioplastics.
{"title":"Converting a D-/L lactic acid bacteria to its d-type counterpart via a combined chemical mutagenesis and biosensor screening method, and its application in lignocellulosic biorefinery","authors":"Xingwang Ma , Kang Yan , Yuwei Zhang , Xiaoyu Xie , Shujie Zou , Yuanyuan Sha , Rui Zhai , Zhaoxian Xu , Mingjie Jin","doi":"10.1016/j.biortech.2025.132471","DOIUrl":"10.1016/j.biortech.2025.132471","url":null,"abstract":"<div><div>Optically pure lactic acid is essential for poly(lactic acid) manufacturing, nonetheless, most wild-type lactic acid bacteria inherently produce D-/L- mixed lactic acid. In this study, an elaborate system was designed for developing <span>d</span>-lactic acid producing mutants from a wild-type D-/L- lactic acid producing<!--> <!-->Lactobacillus by combining chemical mutagenesis with ethyl methane sulfonate as the mutagen and high throughput screening with a <span>l</span>-lactate dehydrogenase based biosensor. Mechanistic analysis revealed that the loss of <span>l</span>-lactate dehydrogenase activity via C → T transitions in the corresponding gene is responsible for generation of <span>d</span>-lactic acid producing mutants. The obtained <span>d</span>-lactic acid producing mutant exhibited excellent performance in different types of lignocellulosic hydrolysates and produced 128.3 g/L <span>d</span>-lactic acid from corn stover hydrolysate in 3-L bioreactor fermentation, with optical purity higher than 98 %. In conclusion, this study provided a practical framework for obtaining optically pure lactic acid producers without genetic engineering operations, advancing the sustainable production of cellulosic bioplastics.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132471"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760223","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}
The thermodynamics and kinetics effects of activators on the simultaneous activation pyrolysis of microalgae remain unclear. This study addresses this gap by investigating the effects of activators (KOH, KHCO3, CH3COOK, K2CO3) on Spirulina platensis (SP) pyrolysis using thermogravimetric-Fourier transform infrared spectrometer (TG-FTIR) and isoconversion methods. The results showed that all activators reduced the initial decomposition temperature of SP, leading to the earlier release of volatile pyrolysis products. Kinetics analysis further revealed that the addition of activators lowered the apparent activation energy (Eα) in the initial pyrolysis stage of SP. However, as the devolatilization process transitioned to the charring stage, the Eα gradually increased, surpassing that of SP pyrolyzed alone. Thermodynamic analysis indicated that the carbonization process of microalgae in the presence of activators required higher energy absorption. These findings reveal the mechanisms of activators in microalgae pyrolysis and provide insights into biochar production.
{"title":"Comprehensive investigation of activator influence on pyrolysis kinetics, thermodynamics, and product characteristics in one-step activated carbon preparation from spirulina","authors":"Ruihan Dong, Ziyue Tang, Yang Yang, Yingquan Chen, Xianhua Wang, Wei Cheng, Haiping Yang, Hanping Chen","doi":"10.1016/j.biortech.2025.132472","DOIUrl":"10.1016/j.biortech.2025.132472","url":null,"abstract":"<div><div>The thermodynamics and kinetics effects of activators on the simultaneous activation pyrolysis of microalgae remain unclear. This study addresses this gap by investigating the effects of activators (KOH, KHCO<sub>3</sub>, CH<sub>3</sub>COOK, K<sub>2</sub>CO<sub>3</sub>) on Spirulina platensis (SP) pyrolysis using thermogravimetric-Fourier transform infrared spectrometer (TG-FTIR) and isoconversion methods. The results showed that all activators reduced the initial decomposition temperature of SP, leading to the earlier release of volatile pyrolysis products. Kinetics analysis further revealed that the addition of activators lowered the apparent activation energy (<em>E<sub>α</sub></em>) in the initial pyrolysis stage of SP. However, as the devolatilization process transitioned to the charring stage, the <em>E<sub>α</sub></em> gradually increased, surpassing that of SP pyrolyzed alone. Thermodynamic analysis indicated that the carbonization process of microalgae in the presence of activators required higher energy absorption. These findings reveal the mechanisms of activators in microalgae pyrolysis and provide insights into biochar production.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132472"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768907","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 study proposes an innovative ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) pretreatment strategy for simultaneous methane and phosphorus (P) recovery from waste activated sludge (WAS). Pretreatment with 7.5 mmol/L EDTA-2Na disrupted sludge floc structures via metal-chelating effects, enhancing short-chain fatty acids (SCFAs) by 1.4-fold and methane production by 1.3-fold during anaerobic digestion. After EDTA-2Na pretreatment, 48.9 % of total phosphorus (TP) was released from the sludge in the methane-production phase, and in the phosphorus recovery phase, another 32.3 % of TP was released under the synergistic promotion of EDTA-2Na pretreatment and acidification. Recovered P crystallized as vivianite with 81.1 % efficiency and 73.1 % purity. This approach demonstrates sustainable sludge management by integrating methane and P recovery through EDTA-2Na pretreatment in anaerobic digestion.
{"title":"Simultaneous methane and phosphorus recovery from waste activated sludge: Critical role of pretreatment by ethylenediaminetetraacetic acid disodium salt in anaerobic digestion","authors":"Yucheng Zou, Xuzhe Zuo, Bo Wang, Meng Bai, Yu Dai, Yiyuan Xing, Xiaodi Li, Yongzhen Peng","doi":"10.1016/j.biortech.2025.132469","DOIUrl":"10.1016/j.biortech.2025.132469","url":null,"abstract":"<div><div>This study proposes an innovative ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) pretreatment strategy for simultaneous methane and phosphorus (P) recovery from waste activated sludge (WAS). Pretreatment with 7.5 mmol/L EDTA-2Na disrupted sludge floc structures via metal-chelating effects, enhancing short-chain fatty acids (SCFAs) by 1.4-fold and methane production by 1.3-fold during anaerobic digestion. After EDTA-2Na pretreatment, 48.9 % of total phosphorus (TP) was released from the sludge in the methane-production phase, and in the phosphorus recovery phase, another 32.3 % of TP was released under the synergistic promotion of EDTA-2Na pretreatment and acidification. Recovered P crystallized as vivianite with 81.1 % efficiency and 73.1 % purity. This approach demonstrates sustainable sludge management by integrating methane and P recovery through EDTA-2Na pretreatment in anaerobic digestion.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"428 ","pages":"Article 132469"},"PeriodicalIF":9.7,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143768993","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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