Escherichia coli MLB(MG1655ΔpflBΔldhA),which can hardly grow on glucose with little succinate accumulation under anaerobic conditions.Two-stage fermentation is a fermentation in which the first stage is used for cel...Escherichia coli MLB(MG1655ΔpflBΔldhA),which can hardly grow on glucose with little succinate accumulation under anaerobic conditions.Two-stage fermentation is a fermentation in which the first stage is used for cell growth and the second stage is used for product production.The ability of glucose consumption and succinate production of MLB under anaerobic conditions can be improved significantly by using acetate as the solo carbon source under aerobic condition during the two-stage fermentation.Then,the adaptive laboratory evolution(ALE)of growing on acetate was applied here.We assumed that the activities of succinate production related enzymes might be further improved in this study.E.coli MLB46-05 evolved from MLB and it had an improved growth phenotype on acetate.Interestingly,in MLB46-05,the yield and tolerance of succinic acid in the anaerobic condition of two-stage fermentation were improved significantly.According to transcriptome analysis,upregulation of the glyoxylate cycle and the activity of stress regulatory factors are the possible reasons for the elevated yield.And the increased tolerance to acetate made it more tolerant to high concentrations of glucose and succinate.Finally,strain MLB46-05 produced 111 g/L of succinic acid with a product yield of 0.74 g/g glucose.展开更多
Saccharomyces cerevisiae is the main yeast used in the winemaking industry.Its innate glucophilicity provokes a discrepancy in glucose and fructose consumption during alcoholic fermentation of grape must,which,combine...Saccharomyces cerevisiae is the main yeast used in the winemaking industry.Its innate glucophilicity provokes a discrepancy in glucose and fructose consumption during alcoholic fermentation of grape must,which,combined with the inhibitory effect of ethanol accumulated in the fermentation broth,might lead to stuck or sluggish fermentations.In the present study,we realized an Adaptive Laboratory Evolution strategy,where an alcoholic fermentation of a 20 g/L fructose broth was followed by cell selection in a high ethanol concentration environment,employed in two different S.cerevisiae strains,named CFB and BLR.The evolved populations originated from each strain after 100 generations of evolution exhibited diverse fermentative abilities.One evolved population,originated from CFB strain,fermented a synthetic broth of 100 g/L glucose and 100 g/L fructose to dryness in 170 h,whereas the parental strain did not complete the fermentation even after 1000 h of incubation.The parameters of growth of the parental and evolved populations of the present study,as well as of the ethanol tolerant populations acquired in a previous study,when grown in a synthetic broth of 100 g/L glucose and 100 g/L fructose,were calculated through a kinetic model,and were compared to each other in order to identify the effect of evolution on the biochemical behavior of the strains.Finally,in a 200 g/L fructose synthetic broth fermentation,only the evolved population derived from CFB strain showed improved fermentative behavior than its parental strain.展开更多
The potential of microalgae as a biological resource for carbon capture,utilization,and storage(CCUS)has been extensively discussed.Although genetic engineering methods have been employed to improve microalgal phenoty...The potential of microalgae as a biological resource for carbon capture,utilization,and storage(CCUS)has been extensively discussed.Although genetic engineering methods have been employed to improve microalgal phenotypes,they often face challenges related to public concerns regarding genetically modified organisms.By contrast,adaptive laboratory evolution(ALE)and microbiome optimization have emerged as promising non-genetic modification strategies,with notable success in bacterial models.In microalgae,ALE has been employed to improve resilience against varying environmental and stress factors and increase carbon capture efficiency,and for the production of valuable bioproducts through gradual accumulation of beneficial mutations following manual or automated selection.Furthermore,advancements in the understanding of microbial symbiotic relationships in the phycosphere have facilitated microbiome optimization in microalgal cultivation systems,significantly improving their functionality and productivity.In this study,we provide a comprehensive overview of the latest advancements in ALE and microbiome optimization of microalgae for CCUS across different carbon emission scenarios,including flue gas,biogas,wastewater,and landfill leachate.We further discuss the current challenges and future directions for the integration of ALE with microbiome optimization,focusing on the potential synergies of these methodologies.Overall,ALE and microbiome optimization are promising approaches to direct microalgae for environmental and industrial CCUS applications,thereby reducing global carbon emissions and addressing climate change challenges.展开更多
Photosynthetic cyanobacteria have shown great potential as“autotrophic cell factories”for the synthesis of fuels and chemicals.However,poor tolerance to various environmental stressors such as high light and heavy m...Photosynthetic cyanobacteria have shown great potential as“autotrophic cell factories”for the synthesis of fuels and chemicals.However,poor tolerance to various environmental stressors such as high light and heavy metals is an important factor limiting their economic viability.While numerous studies have focused on the tolerance mechanism of cyanobacteria to individual stressors,their response to simultaneous stresses remains to be recovered.To investigate the mechanism of cross tolerance to heavymetal Cd^(2+) and high light,the model cyanobacterium Synechocystis sp.PCC 6803 tolerant to both Cd^(2+) and high light was obtained via about 800 days’cross-adaptive laboratory evolution.Three evolutionary strains capable of tolerating both 5.5 μmol·L^(-1) Cd^(2+) and 600 μmol·m^(-2)·s^(-1) high light were successfully obtained,achieving about 83%enhancement of Cd^(2+) tolerance compared with the parent strain.The different response of parent and evolutionary strains to Cd^(2+) was elucidated via metabolomics.Furthermore,a total of 15 genes that were mutated during evolution were identified by whole-genome re-sequencing.Finally,by single-gene knockout and complementation analysis,four genes including ssl2615,sll1732,ssr1480,and sll1659 involved in the improvement of Cd^(2+) tolerance under high-light condition were successfully identified.This work explored the tolerance mechanism of Synechocystis sp.PCC 6803 to cadmium under high-light condition and provided valuable reference for deciphering multitolerance mechanism of cyanobacteria in the future.展开更多
[Objective]To construct an Escherichia coli mutant strain that accumulates pyruvate by genetic modification guided by the genome-scale metabolic network model.[Methods]Using a genome-scale metabolic network model as a...[Objective]To construct an Escherichia coli mutant strain that accumulates pyruvate by genetic modification guided by the genome-scale metabolic network model.[Methods]Using a genome-scale metabolic network model as a guide,we simulated pyruvate production of E.coli,screened key genes in metabolic pathways,and developed gene editing procedures accordingly.We knocked out the acetate kinase gene ackA,phosphate acetyltransferase gene pta,alcohol dehydrogenase adhE,glycogen synthase gene glgA,glycogen phosphorylase gene glgP,phosphoribosyl pyrophosphate(PRPP)synthase gene prs,ribose 1,5-bisphosphate phosphokinase gene phnN,and transporter encoding gene proP.Furthermore,we knocked in the transporter encoding gene ompC,flavonoid toxin gene fldA,and D-serine ammonia lyase gene dsdA.[Results]A shake flask process with the genetically edited mutant strain MG1655-6-2 under anaerobic conditions produced pyruvate at a titer of 10.46 g/L and a yield of 0.69 g/g.Metabolomic analysis revealed a significant increase in the pyruvate level in the fermentation broth,accompanied by notable decreases in the levels of certain related metabolic byproducts.Through 5 L fed-batch fermentation and an adaptive laboratory evolution,the strain finally achieved a pyruvate titer of 45.86 g/L.[Conclusion]This study illustrated the efficacy of a gene editing strategy predicted by a genome-scale metabolic network model in enhancing pyruvate accumulation in E.coli under anaerobic conditions and provided novel insights for microbial metabolic engineering.展开更多
Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and qua...Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.展开更多
D-xylose is an abundant sugar found in plant biomass and can be used as a renewable feedstock for the microbial production of diverse biofuels and bioproducts.However,D-xylose metabolism is slow in many industrial mic...D-xylose is an abundant sugar found in plant biomass and can be used as a renewable feedstock for the microbial production of diverse biofuels and bioproducts.However,D-xylose metabolism is slow in many industrial microorganisms,at least as compared to glucose metabolism.Not surprisingly,a number of approaches have been developed for improving D-xylose metabolism in diverse microorganisms.In this work,we applied a previously developed evolution strategy based on media-in-oil emulsions for improving the growth yield of Escherichia coli NCM3722 on D-xylose.After 30 rounds of evolutions,we isolated multiple mutants with increased growth yield on D-xylose.In addition,we also observed similar increases in the growth rate.Three mutants were selected for whole-genome sequencing.Two mutants had an amber stop mutation in adenylate cyclase,which truncates nearly 60%of the enzyme.However,the ability of this mutant to grow on xylose indicated that truncated enzyme,lacking the C-terminal regulatory domain,is still active.The other mutant had a point mutation in the cyclic AMP receptor protein(CRP),near the high affinity binding site for cyclic AMP.Both mutations,when intro-duced into wild type E.coli,were able to increase the growth yields at levels similar to the isolated mutants.In addition to D-xylose,these mutant strains and their genetic mimics also exhibited higher growth rates and yields on glucose,lactose,and L-arabinose.These results suggest that the improved growth rates and yields are due to changes in the production and sensing of intracellular cyclic AMP concentrations and also suggest native concentrations are suboptimal with respect to the growth rate and yield under the growth conditions tested.Collectively,these results may prove useful for engineering strains of E.coli for high-density fermentations or protein production.展开更多
Photosynthesis is central to life on Earth,employing sunlight,water,and carbon dioxide to produce chemical energy and oxygen.It is generally accepted that boosting its efficiency offers one promising way to increase c...Photosynthesis is central to life on Earth,employing sunlight,water,and carbon dioxide to produce chemical energy and oxygen.It is generally accepted that boosting its efficiency offers one promising way to increase crop yields under agronomically realistic conditions.Since the components,structure,and regulatory mechanisms of the light reactions of photosynthesis are well understood,concepts for enhancing the process have been suggested and partially tested.These approaches vary in complexity,from targeting single components to comprehensive redesign of the whole process on the scales from single cells or tissues to whole canopies.Attempts to enhance light utilization per leaf,by decreasing pigmentation,increasing levels of photosynthetic proteins,prolonging the lifespan of the photosynthetic machinery,or massive reconfiguration of the photosynthetic machinery and the incorporation of nanomaterials,are discussed in this review first.Secondly,strategies intended to optimize the acclimation of photosynthesis to changes in the environment are presented,including redesigning mechanisms to dissipate excess excitation energy(e.g.,non-photochemical quenching)or reduction power(e.g.,flavodiiron proteins).Moreover,schemes for improving acclimation,inspired by natural or laboratory-induced adaptation,are introduced.However,all these endeavors are still in an early exploratory phase and/or have not resulted in the desired outcome,largely because photosynthesis is embedded within large networks of closely interacting cellular and metabolic processes,which can vary among species and even cultivars.This explains why integrated,systems-wide approaches are required to achieve the breakthroughs required for effectively increasing crop yields.展开更多
Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy,which can contribute to copious industrial applications.T...Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy,which can contribute to copious industrial applications.The future and efficacy of such industrial applications relies upon acquiring and/or securing robust methanotrophs with taxonomic and phenotypic diversity.Despite several dramatic advances,isolation of robust methanotrophs is still a long-way challenging task with several lacunae to be filled in sequentially.Methanotrophs with high tolerance to methane can be isolated and cultivated by mimicking natural environs,and adopting strategies like adaptive metabolic evolution.This review summarizes existent and innovative methods for methanotrophic isolation and purification,and their respective applications.A comprehensive description of new insights shedding light upon how to isolate and concomitantly augment robust methanotrophic metabolism in an orchestrated fashion follows.展开更多
Current global energy and environmental crisis have spurred efforts towards developing sustainable biotechnological solutions,such as utilizing CO_(2) and its derivatives as raw materials.Formate is an attractive onec...Current global energy and environmental crisis have spurred efforts towards developing sustainable biotechnological solutions,such as utilizing CO_(2) and its derivatives as raw materials.Formate is an attractive onecarbon source due to its high solubility and low reduction potential.However,the regulatory mechanism of formate metabolism in yeast remains largely unexplored.This study employed adaptive laboratory evolution(ALE)to improve formate tolerance in Saccharomyces cerevisiae and characterized the underlying molecular mechanisms.The evolved strain was applied to produce free fatty acids(FFAs)under high concentration of formate with glucose addition.The results showed that the evolved strain achieved a FFAs titer of 250 mg/L.Overall,this study sheds light on the regulatory mechanism of formate tolerance and provides a platform for future studies under high concentrations of formate.展开更多
Microbial utilization and conversion of organic one-carbon compounds,such as formate and methanol that can be easily produced from CO_(2),has emerged as an attractive approach for biorefinery.In this study,we discover...Microbial utilization and conversion of organic one-carbon compounds,such as formate and methanol that can be easily produced from CO_(2),has emerged as an attractive approach for biorefinery.In this study,we discovered Clostridium beijerinckii NCIMB 8052,a typical solventogenic Clostridium strain,to be a native formate-utilizing bacterium.^(13)C isotope analysis showed that formate could be metabolized via both assimilation and dissimi-lation pathways in C.beijerinckii NCIMB 8052.Notably,the use of formate as the supplementary substrate by this strain could significantly enhance its glucose consumption and ABE(acetone-butanol-ethanol)production,largely due to the up-regulation of genes responsible for glycolysis and glucose transport under formate stress.Based on these findings,we further improved formate tolerance of C.beijerinckii NCIMB 8052 by adaptive lab-oratory evolution,generating an evolved strain Cbei-FA01.The Cbei-FA01 strain could produce 23.0 g/L of ABE solvents using glucose and formate as dual substrates,~50%higher than that of the wild-type strain under the same condition.Moreover,such a promotion effect of formate on ABE production by Cbei-FA01 was also observed in fermenting a glucose-xylose mixture.This work reveals a previously unreported role of formate in biological ABE production,providing a new approach to utilize this one-carbon source.展开更多
基金supported by the National Key R&D Program of China(2021YFC2101300)Science and Technology Commission of Shanghai Municipality(21DZ1209100)Partially supported by Open Funding Project of the State Key Laboratory of Bioreactor Engineering.
文摘Escherichia coli MLB(MG1655ΔpflBΔldhA),which can hardly grow on glucose with little succinate accumulation under anaerobic conditions.Two-stage fermentation is a fermentation in which the first stage is used for cell growth and the second stage is used for product production.The ability of glucose consumption and succinate production of MLB under anaerobic conditions can be improved significantly by using acetate as the solo carbon source under aerobic condition during the two-stage fermentation.Then,the adaptive laboratory evolution(ALE)of growing on acetate was applied here.We assumed that the activities of succinate production related enzymes might be further improved in this study.E.coli MLB46-05 evolved from MLB and it had an improved growth phenotype on acetate.Interestingly,in MLB46-05,the yield and tolerance of succinic acid in the anaerobic condition of two-stage fermentation were improved significantly.According to transcriptome analysis,upregulation of the glyoxylate cycle and the activity of stress regulatory factors are the possible reasons for the elevated yield.And the increased tolerance to acetate made it more tolerant to high concentrations of glucose and succinate.Finally,strain MLB46-05 produced 111 g/L of succinic acid with a product yield of 0.74 g/g glucose.
文摘Saccharomyces cerevisiae is the main yeast used in the winemaking industry.Its innate glucophilicity provokes a discrepancy in glucose and fructose consumption during alcoholic fermentation of grape must,which,combined with the inhibitory effect of ethanol accumulated in the fermentation broth,might lead to stuck or sluggish fermentations.In the present study,we realized an Adaptive Laboratory Evolution strategy,where an alcoholic fermentation of a 20 g/L fructose broth was followed by cell selection in a high ethanol concentration environment,employed in two different S.cerevisiae strains,named CFB and BLR.The evolved populations originated from each strain after 100 generations of evolution exhibited diverse fermentative abilities.One evolved population,originated from CFB strain,fermented a synthetic broth of 100 g/L glucose and 100 g/L fructose to dryness in 170 h,whereas the parental strain did not complete the fermentation even after 1000 h of incubation.The parameters of growth of the parental and evolved populations of the present study,as well as of the ethanol tolerant populations acquired in a previous study,when grown in a synthetic broth of 100 g/L glucose and 100 g/L fructose,were calculated through a kinetic model,and were compared to each other in order to identify the effect of evolution on the biochemical behavior of the strains.Finally,in a 200 g/L fructose synthetic broth fermentation,only the evolved population derived from CFB strain showed improved fermentative behavior than its parental strain.
基金supported by the James Albrecht Graduate Student Fellowship for Z.He,and J.Wang at the Institute of Marine and Environmental Technology(IMET),the University System of Maryland and the DOE Office of Fossil Energy and Carbon Management(FE-0031914 and FE-0032188).
文摘The potential of microalgae as a biological resource for carbon capture,utilization,and storage(CCUS)has been extensively discussed.Although genetic engineering methods have been employed to improve microalgal phenotypes,they often face challenges related to public concerns regarding genetically modified organisms.By contrast,adaptive laboratory evolution(ALE)and microbiome optimization have emerged as promising non-genetic modification strategies,with notable success in bacterial models.In microalgae,ALE has been employed to improve resilience against varying environmental and stress factors and increase carbon capture efficiency,and for the production of valuable bioproducts through gradual accumulation of beneficial mutations following manual or automated selection.Furthermore,advancements in the understanding of microbial symbiotic relationships in the phycosphere have facilitated microbiome optimization in microalgal cultivation systems,significantly improving their functionality and productivity.In this study,we provide a comprehensive overview of the latest advancements in ALE and microbiome optimization of microalgae for CCUS across different carbon emission scenarios,including flue gas,biogas,wastewater,and landfill leachate.We further discuss the current challenges and future directions for the integration of ALE with microbiome optimization,focusing on the potential synergies of these methodologies.Overall,ALE and microbiome optimization are promising approaches to direct microalgae for environmental and industrial CCUS applications,thereby reducing global carbon emissions and addressing climate change challenges.
基金supported by grants from the National Key Research and Development Programof China(2018YFA0903600)well as the National Natural Science Foundation of China(32371486 and 32270091).
文摘Photosynthetic cyanobacteria have shown great potential as“autotrophic cell factories”for the synthesis of fuels and chemicals.However,poor tolerance to various environmental stressors such as high light and heavy metals is an important factor limiting their economic viability.While numerous studies have focused on the tolerance mechanism of cyanobacteria to individual stressors,their response to simultaneous stresses remains to be recovered.To investigate the mechanism of cross tolerance to heavymetal Cd^(2+) and high light,the model cyanobacterium Synechocystis sp.PCC 6803 tolerant to both Cd^(2+) and high light was obtained via about 800 days’cross-adaptive laboratory evolution.Three evolutionary strains capable of tolerating both 5.5 μmol·L^(-1) Cd^(2+) and 600 μmol·m^(-2)·s^(-1) high light were successfully obtained,achieving about 83%enhancement of Cd^(2+) tolerance compared with the parent strain.The different response of parent and evolutionary strains to Cd^(2+) was elucidated via metabolomics.Furthermore,a total of 15 genes that were mutated during evolution were identified by whole-genome re-sequencing.Finally,by single-gene knockout and complementation analysis,four genes including ssl2615,sll1732,ssr1480,and sll1659 involved in the improvement of Cd^(2+) tolerance under high-light condition were successfully identified.This work explored the tolerance mechanism of Synechocystis sp.PCC 6803 to cadmium under high-light condition and provided valuable reference for deciphering multitolerance mechanism of cyanobacteria in the future.
基金supported by the Hebei Provincial Key Research and Development Project(21372803D)。
文摘[Objective]To construct an Escherichia coli mutant strain that accumulates pyruvate by genetic modification guided by the genome-scale metabolic network model.[Methods]Using a genome-scale metabolic network model as a guide,we simulated pyruvate production of E.coli,screened key genes in metabolic pathways,and developed gene editing procedures accordingly.We knocked out the acetate kinase gene ackA,phosphate acetyltransferase gene pta,alcohol dehydrogenase adhE,glycogen synthase gene glgA,glycogen phosphorylase gene glgP,phosphoribosyl pyrophosphate(PRPP)synthase gene prs,ribose 1,5-bisphosphate phosphokinase gene phnN,and transporter encoding gene proP.Furthermore,we knocked in the transporter encoding gene ompC,flavonoid toxin gene fldA,and D-serine ammonia lyase gene dsdA.[Results]A shake flask process with the genetically edited mutant strain MG1655-6-2 under anaerobic conditions produced pyruvate at a titer of 10.46 g/L and a yield of 0.69 g/g.Metabolomic analysis revealed a significant increase in the pyruvate level in the fermentation broth,accompanied by notable decreases in the levels of certain related metabolic byproducts.Through 5 L fed-batch fermentation and an adaptive laboratory evolution,the strain finally achieved a pyruvate titer of 45.86 g/L.[Conclusion]This study illustrated the efficacy of a gene editing strategy predicted by a genome-scale metabolic network model in enhancing pyruvate accumulation in E.coli under anaerobic conditions and provided novel insights for microbial metabolic engineering.
基金Supported by Heilongjiang Natural Science Foundation Joint Guide Project(LH2019C022)。
文摘Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.
基金supported by the Energy Biosciences Institute and by the DOE Center for Advanced Bioenergy and Bioproducts Innovation(U.S.Department of Energy,Office of Science,Office of Biological and Environmental Research under Award Number DE-SC0018420)US Department of Energy,DE-SC0018420,CV Rao.
文摘D-xylose is an abundant sugar found in plant biomass and can be used as a renewable feedstock for the microbial production of diverse biofuels and bioproducts.However,D-xylose metabolism is slow in many industrial microorganisms,at least as compared to glucose metabolism.Not surprisingly,a number of approaches have been developed for improving D-xylose metabolism in diverse microorganisms.In this work,we applied a previously developed evolution strategy based on media-in-oil emulsions for improving the growth yield of Escherichia coli NCM3722 on D-xylose.After 30 rounds of evolutions,we isolated multiple mutants with increased growth yield on D-xylose.In addition,we also observed similar increases in the growth rate.Three mutants were selected for whole-genome sequencing.Two mutants had an amber stop mutation in adenylate cyclase,which truncates nearly 60%of the enzyme.However,the ability of this mutant to grow on xylose indicated that truncated enzyme,lacking the C-terminal regulatory domain,is still active.The other mutant had a point mutation in the cyclic AMP receptor protein(CRP),near the high affinity binding site for cyclic AMP.Both mutations,when intro-duced into wild type E.coli,were able to increase the growth yields at levels similar to the isolated mutants.In addition to D-xylose,these mutant strains and their genetic mimics also exhibited higher growth rates and yields on glucose,lactose,and L-arabinose.These results suggest that the improved growth rates and yields are due to changes in the production and sensing of intracellular cyclic AMP concentrations and also suggest native concentrations are suboptimal with respect to the growth rate and yield under the growth conditions tested.Collectively,these results may prove useful for engineering strains of E.coli for high-density fermentations or protein production.
基金European Research Council(Action Acronym:PhotoRedesign,Action number:854126,Action Title:Rede-signing the Photosynthetic Light Reactions)German Science Founda-tion(DFG)(Transregional Collaborative Research Center 175(TR175)and Excellence Cluster e-conversion)Munich Multiscale Bio-fabrication Network.
文摘Photosynthesis is central to life on Earth,employing sunlight,water,and carbon dioxide to produce chemical energy and oxygen.It is generally accepted that boosting its efficiency offers one promising way to increase crop yields under agronomically realistic conditions.Since the components,structure,and regulatory mechanisms of the light reactions of photosynthesis are well understood,concepts for enhancing the process have been suggested and partially tested.These approaches vary in complexity,from targeting single components to comprehensive redesign of the whole process on the scales from single cells or tissues to whole canopies.Attempts to enhance light utilization per leaf,by decreasing pigmentation,increasing levels of photosynthetic proteins,prolonging the lifespan of the photosynthetic machinery,or massive reconfiguration of the photosynthetic machinery and the incorporation of nanomaterials,are discussed in this review first.Secondly,strategies intended to optimize the acclimation of photosynthesis to changes in the environment are presented,including redesigning mechanisms to dissipate excess excitation energy(e.g.,non-photochemical quenching)or reduction power(e.g.,flavodiiron proteins).Moreover,schemes for improving acclimation,inspired by natural or laboratory-induced adaptation,are introduced.However,all these endeavors are still in an early exploratory phase and/or have not resulted in the desired outcome,largely because photosynthesis is embedded within large networks of closely interacting cellular and metabolic processes,which can vary among species and even cultivars.This explains why integrated,systems-wide approaches are required to achieve the breakthroughs required for effectively increasing crop yields.
基金This work is supported by the National Key R&D Program of China(2018YFA0901500)National Natural Science Foundation of China(21878241)and Open Funding Project of the State Key Laboratory of Bioreactor Engineering.
文摘Methanotrophic bacteria are entities with innate biocatalytic potential to biofilter and oxidize methane into simpler compounds concomitantly conserving energy,which can contribute to copious industrial applications.The future and efficacy of such industrial applications relies upon acquiring and/or securing robust methanotrophs with taxonomic and phenotypic diversity.Despite several dramatic advances,isolation of robust methanotrophs is still a long-way challenging task with several lacunae to be filled in sequentially.Methanotrophs with high tolerance to methane can be isolated and cultivated by mimicking natural environs,and adopting strategies like adaptive metabolic evolution.This review summarizes existent and innovative methods for methanotrophic isolation and purification,and their respective applications.A comprehensive description of new insights shedding light upon how to isolate and concomitantly augment robust methanotrophic metabolism in an orchestrated fashion follows.
基金the National Key R&D Program of China[2021YFC2103500]Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project[TSBICIP-KJGG-009]+1 种基金National Natural Science Foundation of China[22211530047]Beijing Advanced Innovation Center for Soft Matter Science and Engineering,Beijing University of Chemical Technology。
文摘Current global energy and environmental crisis have spurred efforts towards developing sustainable biotechnological solutions,such as utilizing CO_(2) and its derivatives as raw materials.Formate is an attractive onecarbon source due to its high solubility and low reduction potential.However,the regulatory mechanism of formate metabolism in yeast remains largely unexplored.This study employed adaptive laboratory evolution(ALE)to improve formate tolerance in Saccharomyces cerevisiae and characterized the underlying molecular mechanisms.The evolved strain was applied to produce free fatty acids(FFAs)under high concentration of formate with glucose addition.The results showed that the evolved strain achieved a FFAs titer of 250 mg/L.Overall,this study sheds light on the regulatory mechanism of formate tolerance and provides a platform for future studies under high concentrations of formate.
基金supported by the National Key R&D Program of China(2018YFA0901500,2021YFC2103500)Science and Technology Commission of Shanghai Municipality(21DZ1209100)+1 种基金DNL Coopera-tion Fund,CAS(DNL202013)Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-KJGG-016).
文摘Microbial utilization and conversion of organic one-carbon compounds,such as formate and methanol that can be easily produced from CO_(2),has emerged as an attractive approach for biorefinery.In this study,we discovered Clostridium beijerinckii NCIMB 8052,a typical solventogenic Clostridium strain,to be a native formate-utilizing bacterium.^(13)C isotope analysis showed that formate could be metabolized via both assimilation and dissimi-lation pathways in C.beijerinckii NCIMB 8052.Notably,the use of formate as the supplementary substrate by this strain could significantly enhance its glucose consumption and ABE(acetone-butanol-ethanol)production,largely due to the up-regulation of genes responsible for glycolysis and glucose transport under formate stress.Based on these findings,we further improved formate tolerance of C.beijerinckii NCIMB 8052 by adaptive lab-oratory evolution,generating an evolved strain Cbei-FA01.The Cbei-FA01 strain could produce 23.0 g/L of ABE solvents using glucose and formate as dual substrates,~50%higher than that of the wild-type strain under the same condition.Moreover,such a promotion effect of formate on ABE production by Cbei-FA01 was also observed in fermenting a glucose-xylose mixture.This work reveals a previously unreported role of formate in biological ABE production,providing a new approach to utilize this one-carbon source.
