Pub Date : 2025-02-28DOI: 10.1016/j.biortech.2025.132326
Jo Hyun Moon, Jihoon Woo, Joon Young Park, Myung Hyun Noh, Donghyuk Kim, Gyoo Yeol Jung
Acetate is a cost-effective and sustainable carbon source that, despite its potential, remains underutilized. This study employed biosensor-assisted adaptive laboratory evolution (ALE) to enhance itaconic acid production and acetate metabolism in Escherichia coli. The evolved E. coli W strains exhibited 65% increase in itaconic acid production and 71% increase in growth rate, and 45% increase in itaconic acid yield. A common 31-kb genomic deletion was identified in the evolved strains, with two genes, ecw_m2276 and ecw_m2277, driving the observed phenotypic changes. The evolved strains exhibited an intensified stringent response, which enhanced the acetate-utilizing pathway and resulted in over a 5,000% increase in the expression of the glyoxylate shunt, thereby boosting microbial growth. Overexpression of relA further replicated these enhanced phenotypes. Our findings highlight not only significant physiological improvements but also present a novel strategy for enhancing microbial growth and bioproduction from acetate, offering valuable insights for industrial biotechnology applications.
{"title":"Biosensor-guided evolution boosts itaconic acid production, unveiling unique insights into the stringent response.","authors":"Jo Hyun Moon, Jihoon Woo, Joon Young Park, Myung Hyun Noh, Donghyuk Kim, Gyoo Yeol Jung","doi":"10.1016/j.biortech.2025.132326","DOIUrl":"https://doi.org/10.1016/j.biortech.2025.132326","url":null,"abstract":"<p><p>Acetate is a cost-effective and sustainable carbon source that, despite its potential, remains underutilized. This study employed biosensor-assisted adaptive laboratory evolution (ALE) to enhance itaconic acid production and acetate metabolism in Escherichia coli. The evolved E. coli W strains exhibited 65% increase in itaconic acid production and 71% increase in growth rate, and 45% increase in itaconic acid yield. A common 31-kb genomic deletion was identified in the evolved strains, with two genes, ecw_m2276 and ecw_m2277, driving the observed phenotypic changes. The evolved strains exhibited an intensified stringent response, which enhanced the acetate-utilizing pathway and resulted in over a 5,000% increase in the expression of the glyoxylate shunt, thereby boosting microbial growth. Overexpression of relA further replicated these enhanced phenotypes. Our findings highlight not only significant physiological improvements but also present a novel strategy for enhancing microbial growth and bioproduction from acetate, offering valuable insights for industrial biotechnology applications.</p>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":" ","pages":"132326"},"PeriodicalIF":9.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536231","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 : 2025-02-28DOI: 10.1016/j.biortech.2025.132319
Hao Yao , Yuandong Xiong , Chris Pickles , Ron Hutcheon , Mika Pahnila , Anton Hagström , Timo Fabritius , Mamdouh Omran
Knowledge of the dielectric properties (complex permittivities) of biomasses is critical for understanding their behaviors in a microwave field and for designing large-scale microwave systems. The present research was focused on determining the dielectric properties of different types of biomasses (sawdust, bark, fiber reject, grass, and straw) at temperatures from 25 to 700 °C and frequencies in the range of 397 to 2985 MHz, using cavity perturbation technique. The dielectric properties decreased during the drying (25 to 200 °C) and the pyrolysis stages (200 to 400 °C), but sharply increased during the biochar formation stage (400 to 700 °C). At 912 MHz, straw, grass, and fiber reject exhibited the greatest half-power depths at approximately 300 °C, and sawdust and bark at approximately 350 °C, suggesting that from room temperature to 350 °C, larger material volumes can reduce costs; above 500 °C, the sample size must not exceed the microwave half-power depth to prevent hot spots or uneven heating. The interaction mechanisms of microwaves with biomass can be explained as follows, during biomass drying, the dielectric changes are driven by dipolar polarization of water molecules; during pyrolysis, by polar molecules and functional groups; and during carbonization, by scattering and interface polarization within the biochar. Furthermore, the addition of the produced biochar to the raw biomass could increase the loss tangent up to 400 °C, enabling faster heating and reducing energy consumptions and residence times. The dielectric properties data provided in this study can be used to design large-scale microwave systems, including selection of column diameter, sample size, and microwave frequency.
{"title":"Dielectric properties of biomass by-products generated from wood and agricultural industries in Finland","authors":"Hao Yao , Yuandong Xiong , Chris Pickles , Ron Hutcheon , Mika Pahnila , Anton Hagström , Timo Fabritius , Mamdouh Omran","doi":"10.1016/j.biortech.2025.132319","DOIUrl":"10.1016/j.biortech.2025.132319","url":null,"abstract":"<div><div>Knowledge of the dielectric properties (complex permittivities) of biomasses is critical for understanding their behaviors in a microwave field and for designing large-scale microwave systems. The present research was focused on determining the dielectric properties of different types of biomasses (sawdust, bark, fiber reject, grass, and straw) at temperatures from 25 to 700 °C and frequencies in the range of 397 to 2985 MHz, using cavity perturbation technique. The dielectric properties decreased during the drying (25 to 200 °C) and the pyrolysis stages (200 to 400 °C), but sharply increased during the biochar formation stage (400 to 700 °C). At 912 MHz, straw, grass, and fiber reject exhibited the greatest half-power depths at approximately 300 °C, and sawdust and bark at approximately 350 °C, suggesting that from room temperature to 350 °C, larger material volumes can reduce costs; above 500 °C, the sample size must not exceed the microwave half-power depth to prevent hot spots or uneven heating. The interaction mechanisms of microwaves with biomass can be explained as follows, during biomass drying, the dielectric changes are driven by dipolar polarization of water molecules; during pyrolysis, by polar molecules and functional groups; and during carbonization, by scattering and interface polarization within the biochar. Furthermore, the addition of the produced biochar to the raw biomass could increase the loss tangent up to 400 °C, enabling faster heating and reducing energy consumptions and residence times. The dielectric properties data provided in this study can be used to design large-scale microwave systems, including selection of column diameter, sample size, and microwave frequency.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"426 ","pages":"Article 132319"},"PeriodicalIF":9.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536236","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 : 2025-02-28DOI: 10.1016/j.biortech.2025.132322
Wei Chong , Shaohua Wang , Jiaxin Cheng , Xue Lou , Xuebao Wan , Xiangyu Sun , Mingyang Wang , Shaoping Kuang , Hui Chen , Shuai Liu
Denitrifying Anaerobic Methane Oxidation (DAMO), which utilizes methane for denitrification, offers an efficacious approach for nitrogen removal in wastewater and greenhouse gas mitigation. However, slow microbial growth and low methane mass transfer efficiency limit its practical application. This study demonstrates that straw biochar, particularly when pyrolyzed at 300 °C, enhances DAMO’s nitrogen removal performance. Specifically, biochar from cotton (CB300) and maize (MB300) stalks at 300 °C increased the nitrate removal rate by 2.6 and 2.4 times, respectively, compared to the control. Correlation analysis revealed a positive link between nitrate removal rates and oxygen-containing functional groups in biochar, which may facilitate electron transfer. Long-term DAMO reactor operation confirmed significant enhancements in nitrogen removal with 300 °C biochars. CB300 and MB300 biochars increased key functional genes (mcrA and pmoA) and enriched DAMO archaea (ANME-2D). These findings suggest that low-temperature biochar is a cost-effective and sustainable approach to enhance the nitrogen removal performance of DAMO.
{"title":"Enhancing denitrifying anaerobic methane oxidation for nitrogen removal with low-temperature biochar","authors":"Wei Chong , Shaohua Wang , Jiaxin Cheng , Xue Lou , Xuebao Wan , Xiangyu Sun , Mingyang Wang , Shaoping Kuang , Hui Chen , Shuai Liu","doi":"10.1016/j.biortech.2025.132322","DOIUrl":"10.1016/j.biortech.2025.132322","url":null,"abstract":"<div><div>Denitrifying Anaerobic Methane Oxidation (DAMO), which utilizes methane for denitrification, offers an efficacious approach for nitrogen removal in wastewater and greenhouse gas mitigation. However, slow microbial growth and low methane mass transfer efficiency limit its practical application. This study demonstrates that straw biochar, particularly when pyrolyzed at 300 °C, enhances DAMO’s nitrogen removal performance. Specifically, biochar from cotton (CB300) and maize (MB300) stalks at 300 °C increased the nitrate removal rate by 2.6 and 2.4 times, respectively, compared to the control. Correlation analysis revealed a positive link between nitrate removal rates and oxygen-containing functional groups in biochar, which may facilitate electron transfer. Long-term DAMO reactor operation confirmed significant enhancements in nitrogen removal with 300 °C biochars. CB300 and MB300 biochars increased key functional genes (<em>mcrA</em> and <em>pmoA</em>) and enriched DAMO archaea (<em>ANME-2D</em>). These findings suggest that low-temperature biochar is a cost-effective and sustainable approach to enhance the nitrogen removal performance of DAMO.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132322"},"PeriodicalIF":9.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536156","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 : 2025-02-27DOI: 10.1016/j.biortech.2025.132314
Fabiano Asunis, Paolo Dessì, Giorgia De Gioannis, Aldo Muntoni
This study presents a novel four-stage process for polyhydroxyalkanoates (PHA) production from nutrient-rich sheep cheese whey (CW). The key advancement was the integration of a volatile fatty acid (VFA) extraction stage into the conventional three-stage PHA production process. Application of membrane separation to fermented cheese whey resulted in the generation of a "retentate" stream containing both organic acids and nutrients, suitable for microbial culture selection, and a VFA-rich but nutrient deprived "permeate" stream, ideal for PHA accumulation. Thus, the carbon-to-nitrogen (C/N) ratio was optimized for both the selection and accumulation stages, which is crucial for efficient PHA production and for eliminating the need for exogenous nitrogen addition. The integrated process resulted in significantly higher yields (0.55 vs 0.26 gC-PHA gC-OA-1) and PHA content (37% vs 28%) than the control, where fermented cheese whey was directly used as feedstock for the accumulation stage. The results highlight the potential of this approach for optimizing PHA production from sub-optimal, nutrient-rich substrates.
{"title":"VFA extraction through silicone membrane fosters PHA production from nutrient-rich biowaste.","authors":"Fabiano Asunis, Paolo Dessì, Giorgia De Gioannis, Aldo Muntoni","doi":"10.1016/j.biortech.2025.132314","DOIUrl":"https://doi.org/10.1016/j.biortech.2025.132314","url":null,"abstract":"<p><p>This study presents a novel four-stage process for polyhydroxyalkanoates (PHA) production from nutrient-rich sheep cheese whey (CW). The key advancement was the integration of a volatile fatty acid (VFA) extraction stage into the conventional three-stage PHA production process. Application of membrane separation to fermented cheese whey resulted in the generation of a \"retentate\" stream containing both organic acids and nutrients, suitable for microbial culture selection, and a VFA-rich but nutrient deprived \"permeate\" stream, ideal for PHA accumulation. Thus, the carbon-to-nitrogen (C/N) ratio was optimized for both the selection and accumulation stages, which is crucial for efficient PHA production and for eliminating the need for exogenous nitrogen addition. The integrated process resulted in significantly higher yields (0.55 vs 0.26 g<sub>C-PHA</sub> g<sub>C-OA</sub><sup>-1</sup>) and PHA content (37% vs 28%) than the control, where fermented cheese whey was directly used as feedstock for the accumulation stage. The results highlight the potential of this approach for optimizing PHA production from sub-optimal, nutrient-rich substrates.</p>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":" ","pages":"132314"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536166","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 : 2025-02-27DOI: 10.1016/j.biortech.2025.132312
Minyu Suo , Lingxiu Liu , Hongye Fan , Nan Li , Hua Pan , Dzmitry Hrynsphan , Savitskaya Tatsiana , Raúl Robles-Iglesias , Zeyu Wang , Jun Chen
This review provides an insight into the chain-elongation technology for the production of caproic acid, a chemical widely used in the food, pharmaceutical, and cosmetic industries, from lactic acid in waste organic matter. The evolution of the technology is traced, the reaction mechanism is elucidated, and the properties of key microbial agents capable of carrying out the chain-elongation technology are summarized and compared, including pure bacterial isolates and reactor-mixed microorganisms. Furthermore, the parameters that regulate caproic acid formation by influencing microbial activity, competitive pathways, product selection, and carbon flow distribution, such as pH, temperature, electron donor, electron acceptor, and hydrogen partial pressure, are highlighted and discussed. It is worth noting that various caproic acid product extraction technologies were also summarized and assessed. Finally, based on the perspective of interdisciplinary field, bold suggestions for the future research direction are put forward.
{"title":"Advancements in chain elongation technology: Transforming lactic acid into caproic acid for sustainable biochemical production","authors":"Minyu Suo , Lingxiu Liu , Hongye Fan , Nan Li , Hua Pan , Dzmitry Hrynsphan , Savitskaya Tatsiana , Raúl Robles-Iglesias , Zeyu Wang , Jun Chen","doi":"10.1016/j.biortech.2025.132312","DOIUrl":"10.1016/j.biortech.2025.132312","url":null,"abstract":"<div><div>This review provides an insight into the chain-elongation technology for the production of caproic acid, a chemical widely used in the food, pharmaceutical, and cosmetic industries, from lactic acid in waste organic matter. The evolution of the technology is traced, the reaction mechanism is elucidated, and the properties of key microbial agents capable of carrying out the chain-elongation technology are summarized and compared, including pure bacterial isolates and reactor-mixed microorganisms. Furthermore, the parameters that regulate caproic acid formation by influencing microbial activity, competitive pathways, product selection, and carbon flow distribution, such as pH, temperature, electron donor, electron acceptor, and hydrogen partial pressure, are highlighted and discussed. It is worth noting that various caproic acid product extraction technologies were also summarized and assessed. Finally, based on the perspective of interdisciplinary field, bold suggestions for the future research direction are put forward.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132312"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528661","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 : 2025-02-27DOI: 10.1016/j.biortech.2025.132313
Yiping Yuan , Huan Wang , Hongtao He , Zhongnan Zhang , Fang Yang , Yiling Chen , Fuqing Wu , Qiong Wu , Guo-Qiang Chen
Lignocellulose is the most abundant terrestrial biomass type, and lignocellulose hydrolysate has the potential to replace glucose for microbial fermentation. Halomonas bluephagenesis has significant advantages in producing bioplastics polyhydroxyalkanoates (PHA), but there is relatively little research on the use of lignocellulose hydrolysate for this strain. In present study, H. bluephagenesis was engineered to use xylose and lignocellulose hydrolysate to produce PHB. Firstly, four xylose metabolism pathways were established. Secondly, several xfp genes were compared and genes in pathway I (xylA and xfp gene) were integrated into the genome. Thirdly, H. bluephagenesis was found to be able to utilize glucose and xylose simultaneously. H. bluephagenesis T39 containing xylA and xfp generated 15 g/L CDW containing 76 wt% PHB when cultured in lignocellulose hydrolysate, and it was grown to 62 g/L CDW containing 67 wt% PHB in a 7 L bioreactor. H. bluephagenesis T43 harboring xylA was found able to synthesize P(3HB-4HB-3HV) containing 3-hydroxybutyrate (3HB), 4-hydroxybutyrte (4HB) and 3-hydroxyvalerate (3HV) when grown on lignocellulose hydrolysate.
{"title":"Polyhydroxyalkanoate production by engineered Halomonas grown in lignocellulose hydrolysate","authors":"Yiping Yuan , Huan Wang , Hongtao He , Zhongnan Zhang , Fang Yang , Yiling Chen , Fuqing Wu , Qiong Wu , Guo-Qiang Chen","doi":"10.1016/j.biortech.2025.132313","DOIUrl":"10.1016/j.biortech.2025.132313","url":null,"abstract":"<div><div>Lignocellulose is the most abundant terrestrial biomass type, and lignocellulose hydrolysate has the potential to replace glucose for microbial fermentation. <em>Halomonas bluephagenesis</em> has significant advantages in producing bioplastics polyhydroxyalkanoates (PHA), but there is relatively little research on the use of lignocellulose hydrolysate for this strain. In present study, <em>H. bluephagenesis</em> was engineered to use xylose and lignocellulose hydrolysate to produce PHB. Firstly, four xylose metabolism pathways were established<em>.</em> Secondly, several <em>xfp</em> genes were compared and genes in pathway I (<em>xylA</em> and <em>xfp</em> gene) were integrated into the genome. Thirdly, <em>H. bluephagenesis</em> was found to be able to utilize glucose and xylose simultaneously. <em>H. bluephagenesis</em> T39 containing <em>xylA</em> and <em>xfp</em> generated 15 g/L CDW containing 76 wt% PHB when cultured in lignocellulose hydrolysate, and it was grown to 62 g/L CDW containing 67 wt% PHB in a 7 L bioreactor. <em>H. bluephagenesis</em> T43 harboring <em>xylA</em> was found able to synthesize P(3HB-4HB-3HV) containing 3-hydroxybutyrate (3HB), 4-hydroxybutyrte (4HB) and 3-hydroxyvalerate (3HV) when grown on lignocellulose hydrolysate.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132313"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526568","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 : 2025-02-27DOI: 10.1016/j.biortech.2025.132309
Hongyuan Liu , Zirui Zhou , Caicheng Long , Taiping Qing , Bo Feng , Peng Zhang , You-Peng Chen
Recovering the nitrogen-rich biopolymer cyanophycin [(β-Asp-Arg)n] from algal-bacterial consortia enhances the reclamation of value-added chemicals from wastewater. However, the modulation of light/dark conditions on cyanophycin accumulation remain unknown. In this study, the trends and mechanisms of cyanophycin synthesis in algal-bacterial consortia under light/dark conditions were investigated. The results showed that cyanophycin production during the dark periods ranged from 137–150 mg/g MLSS (mixed liquid suspended solids), which was 32 %−38 % higher than those during the light period (p < 0.001). Metatranscriptomics results demonstrated that 50 metagenome-assembled genomes contribute to cyanophycin production, with the Planktothrix genus being the dominant contributor. Metabolomics findings suggested that algal-bacterial consortia produce higher level of arginine for cyanophycin synthesis under light conditions. This study demonstrates the feasibility of increasing cyanophycin production by merging light/dark cycles, and offers a novel strategy for high yield of valuable biopolymers from wastewater substrate.
{"title":"Light/dark synergy enhances cyanophycin accumulation in algal-bacterial consortia: Boosted strategy for nitrogen recovery from wastewater","authors":"Hongyuan Liu , Zirui Zhou , Caicheng Long , Taiping Qing , Bo Feng , Peng Zhang , You-Peng Chen","doi":"10.1016/j.biortech.2025.132309","DOIUrl":"10.1016/j.biortech.2025.132309","url":null,"abstract":"<div><div>Recovering the nitrogen-rich biopolymer cyanophycin [(<em>β</em>-Asp-Arg)<sub>n</sub>] from algal-bacterial consortia enhances the reclamation of value-added chemicals from wastewater. However, the modulation of light/dark conditions on cyanophycin accumulation remain unknown. In this study, the trends and mechanisms of cyanophycin synthesis in algal-bacterial consortia under light/dark conditions were investigated. The results showed that cyanophycin production during the dark periods ranged from 137–150 mg/g MLSS (mixed liquid suspended solids), which was 32 %−38 % higher than those during the light period (<em>p</em> < 0.001). Metatranscriptomics results demonstrated that 50 metagenome-assembled genomes contribute to cyanophycin production, with the <em>Planktothrix</em> genus being the dominant contributor. Metabolomics findings suggested that algal-bacterial consortia produce higher level of arginine for cyanophycin synthesis under light conditions. This study demonstrates the feasibility of increasing cyanophycin production by merging light/dark cycles, and offers a novel strategy for high yield of valuable biopolymers from wastewater substrate.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132309"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528612","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 : 2025-02-27DOI: 10.1016/j.biortech.2025.132310
Wang Yan , Huang Kaiwen , Zhou Yuchen , Wang Bingzheng , Wang Shuo , Li Ji
The adaptability and microbial response mechanism of a sulfur autotrophic denitrification (SADN) biofilm under high nitrate (NO3−-N) and sulfamethoxazole (SMX) stress through long-term operation of a fluidized bioreactor was evaluated. The SADN biofilm adapted to nitrate contents of up to 150 mg/L, and at 1 mg/L SMX, the nitrogen removal efficiency and SMX removal efficiency were as high as 85 % and 64 %, respectively. Microbial adaptation was driven by upregulated secretion of acyl-homoserine lactone (AHL) signal molecules, specifically 3OC6-HSL and 3OC8-HSL, which stabilized at concentrations of 575.7 ng/L and 579.9 ng/L, respectively. These molecules dynamically regulated the composition of extracellular polymeric substances, with total EPS content increasing from 113.37 mg/gVSS in the initial phase to 456.85 mg/gVSS under early SMX exposure, ensuring biofilm structural integrity. Under prolonged SMX stress, Simplicispira emerged as a key genus with a relative abundance of 21.20 %, utilizing apoptotic autotrophic denitrifiers and EPS metabolites as carbon sources for heterotrophic denitrification. This genus harbored critical nitrate reductase genes, including NarG, which accounted for 28.5 % of total functional gene abundance. In addition, SMX stress reduced the abundance of total anti-resistance genes (ARGs), with resistance mechanisms dominated by antibiotic efflux pumps, with the contribution increased from 63 % to 67 %. The relevance of this pump continuously increased, which hindered binding of SMX to cells and effectively reduced its toxicity. The results of this study provide scientific evidence for the application of SADN technology in a high-nitrate and antibiotically stressed environment. The results can further guide practical operations and provide technical support for increasing denitrification efficiency and antibiotic removal capacity in the SADN process.
{"title":"Response characteristics of the microbial community, metabolic pathways, and anti-resistance genes under high nitrate and sulfamethoxazole stress in a fluidized sulfur autotrophic denitrification process","authors":"Wang Yan , Huang Kaiwen , Zhou Yuchen , Wang Bingzheng , Wang Shuo , Li Ji","doi":"10.1016/j.biortech.2025.132310","DOIUrl":"10.1016/j.biortech.2025.132310","url":null,"abstract":"<div><div>The adaptability and microbial response mechanism of a sulfur autotrophic denitrification (SADN) biofilm under high nitrate (NO<sub>3</sub><sup>−</sup>-N) and sulfamethoxazole (SMX) stress through long-term operation of a fluidized bioreactor was evaluated. The SADN biofilm adapted to nitrate contents of up to 150 mg/L, and at 1 mg/L SMX, the nitrogen removal efficiency and SMX removal efficiency were as high as 85 % and 64 %, respectively. Microbial adaptation was driven by upregulated secretion of acyl-homoserine lactone (AHL) signal molecules, specifically 3OC6-HSL and 3OC8-HSL, which stabilized at concentrations of 575.7 ng/L and 579.9 ng/L, respectively. These molecules dynamically regulated the composition of extracellular polymeric substances, with total EPS content increasing from 113.37 mg/gVSS in the initial phase to 456.85 mg/gVSS under early SMX exposure, ensuring biofilm structural integrity. Under prolonged SMX stress, <em>Simplicispira</em> emerged as a key genus with a relative abundance of 21.20 %, utilizing apoptotic autotrophic denitrifiers and EPS metabolites as carbon sources for heterotrophic denitrification. This genus harbored critical nitrate reductase genes, including NarG, which accounted for 28.5 % of total functional gene abundance. In addition, SMX stress reduced the abundance of total anti-resistance genes (ARGs), with resistance mechanisms dominated by antibiotic efflux pumps, with the contribution increased from 63 % to 67 %. The relevance of this pump continuously increased, which hindered binding of SMX to cells and effectively reduced its toxicity. The results of this study provide scientific evidence for the application of SADN technology in a high-nitrate and antibiotically stressed environment. The results can further guide practical operations and provide technical support for increasing denitrification efficiency and antibiotic removal capacity in the SADN process.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132310"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526569","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}
Chlorophylls face significant challenges in practical applications due to their low physicochemical stability. This study investigated the stability of chlorophylls within chlorophyll-protein complexes derived from Auxenochlorella pyrenoidosa and developed a novel surfactant-assisted enzymatic modification strategy to enhance chlorophyll stability. Enzymatic hydrolysis with papain in the presence of Tween 80 increased chlorophyll retention to 88.77%, compared to 78.69% without surfactant, with improved stability observed across a wide temperature range (4–80°C), maintaining chlorophyll retention between 69.41% and 85.09%, as well as under acidic conditions. Mass spectrometry identified 26 chlorophylls and their derivatives, while Tween 80 mitigated the conversion of chlorophylls into undesirable brown compounds, such as pheophytins. Peptidomics and molecular docking analysis revealed that hydrophobic and hydrogen bonding interactions between chlorophylls and specific chlorophyll-binding peptides contributed to enhanced stability. This study presents a promising approach for improving chlorophyll stability through native chlorophyll-binding proteins, particularly for applications in protein-based food matrices.
{"title":"Establishment of a surfactant-assisted enzymatic modification method for chlorophyll-protein complexes from Auxenochlorella pyrenoidosa to improve chlorophyll stability","authors":"Bijun Hao , Zihao Zhu , Wenhan Zhang , Yaoguang Chang , Yanchao Wang , Changhu Xue","doi":"10.1016/j.biortech.2025.132311","DOIUrl":"10.1016/j.biortech.2025.132311","url":null,"abstract":"<div><div>Chlorophylls face significant challenges in practical applications due to their low physicochemical stability. This study investigated the stability of chlorophylls within chlorophyll-protein complexes derived from <em>Auxenochlorella pyrenoidosa</em> and developed a novel surfactant-assisted enzymatic modification strategy to enhance chlorophyll stability. Enzymatic hydrolysis with papain in the presence of Tween 80 increased chlorophyll retention to 88.77%, compared to 78.69% without surfactant, with improved stability observed across a wide temperature range (4–80°C), maintaining chlorophyll retention between 69.41% and 85.09%, as well as under acidic conditions. Mass spectrometry identified 26 chlorophylls and their derivatives, while Tween 80 mitigated the conversion of chlorophylls into undesirable brown compounds, such as pheophytins. Peptidomics and molecular docking analysis revealed that hydrophobic and hydrogen bonding interactions between chlorophylls and specific chlorophyll-binding peptides contributed to enhanced stability. This study presents a promising approach for improving chlorophyll stability through native chlorophyll-binding proteins, particularly for applications in protein-based food matrices.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132311"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143536159","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}
Microalgae are crucial in carbon capture, utilization, and storage due to the efficient CO2 assimilation through photosynthesis and potential for high-value biochemical production. However, limited research has explored genetic strain to enhance carbon capture under dynamic CO2 conditions. This research aimed to optimize carbon capture in Chlorella sorokiniana by introducing pyridoxal kinase (pdxY) and cultivation in fluctuating CO2 concentrations. The sequential optimization successfully led to 34% increase in growth with improved carbon capture efficiency to 88.5%. Transgenic strains 2023PY and BSLPY demonstrated superior performance under high (2%) and low (0.04%) CO2, respectively. Addition of Tris base to the medium stabilized pH at favorable level, which is crucial for optimum growth. Scale-up cultivation in 2-L photobioreactor achieved net-zero carbon emissions across all strains. These findings highlight the potential of genetic engineering and process optimization in advancing microalgal carbon capture, along with the production of protein, starch, and lipid for sustainable applications.
{"title":"Enhanced carbon capture and utilization in transgenic Chlorella sorokiniana harboring pyridoxal kinase under dynamic carbon dioxide levels","authors":"Ruei-Xuan Liang , Jo-Chi Hung , Priskila Adjani Diankristanti, Yen-Tung Chen, Cheng-Wei Chung, I-Son Ng","doi":"10.1016/j.biortech.2025.132315","DOIUrl":"10.1016/j.biortech.2025.132315","url":null,"abstract":"<div><div>Microalgae are crucial in carbon capture, utilization, and storage due to the efficient CO<sub>2</sub> assimilation through photosynthesis and potential for high-value biochemical production. However, limited research has explored genetic strain to enhance carbon capture under dynamic CO<sub>2</sub> conditions. This research aimed to optimize carbon capture in <em>Chlorella sorokiniana</em> by introducing pyridoxal kinase (<em>pdx</em>Y) and cultivation in fluctuating CO<sub>2</sub> concentrations. The sequential optimization successfully led to 34% increase in growth with improved carbon capture efficiency to 88.5%. Transgenic strains 2023PY and BSLPY demonstrated superior performance under high (2%) and low (0.04%) CO<sub>2</sub>, respectively. Addition of Tris base to the medium stabilized pH at favorable level, which is crucial for optimum growth. Scale-up cultivation in 2-L photobioreactor achieved net-zero carbon emissions across all strains. These findings highlight the potential of genetic engineering and process optimization in advancing microalgal carbon capture, along with the production of protein, starch, and lipid for sustainable applications.</div></div>","PeriodicalId":258,"journal":{"name":"Bioresource Technology","volume":"425 ","pages":"Article 132315"},"PeriodicalIF":9.7,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528662","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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