Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological proce...Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.展开更多
Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Halo...Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Haloactinopolyspora alba DSM 45211(HaAC),respectively.The recombinant ThAC and HaAC were expressed in Escherichia coli with molecular weights of 36.1 and 36.0 kDa respectively.The presence of 2500 and 2200 mmolL^(-1)1 NaCl significantly enhanced the enzyme activities of ThAC and HaAC,with 22-fold and 7.4-fold higher activities compared to those without NaCl,respectively.Several divalent metal ions were found to activate the recombinant ACs to different extents,and the optimal metal ion was Mg^(2+)for both ThAC and HaAC with concentrations of 80 mmol·L^(-1) and 40 mmol·L^(-1) respectively.Purified ThAC and HaAC had the optimal specific activities((4.59±0.35)×10^(4) and(7.76±0.52)×10^(4) U·mg^(-1))and catalytic efficiency(4.47 and 5.30 L·mmol^(-1)·s^(-1))at 45℃ and 40℃ respectively,while the optimum pH of both two recombinant ACs was 10.0.This is the first report of the halophilic Class III ACs,which could make new contributions to explore and study ACs for further associated investigations.展开更多
Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-...Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.展开更多
Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only sav...Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only save resource,cost,and operating time but also reduce the number of reaction steps,and avoid separating unstable intermediates,leading to the generation of more products under greener circumstances and thereby playing an indispensable role in the fields of medicine,materials and fine chemicals.Although incompatible challenges between chemocatalyst and biocatalyst remain,strategies such as biphasic system,artificial metalloenzymes,immobilization or supramolecular host,and protein engineering have been designed to overcome these issues.In this review,chemoenzymatic catalysis according to different chemocatalysis types was classifiably described,and in particular,the classic dynamic kinetic resolutions(DKR)and cofactor regeneration were summarized.Finally,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.展开更多
Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the th...Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.展开更多
L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purificati...L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange (DIX) model, which takes the activiW into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest t-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.展开更多
Clostridium acetobutylicum has been extensively exploited to produce biofuels and solvents and its biofilm could dramatically improve the productivities.However,genetic control of C.acetobutylicum biofilm has not been...Clostridium acetobutylicum has been extensively exploited to produce biofuels and solvents and its biofilm could dramatically improve the productivities.However,genetic control of C.acetobutylicum biofilm has not been dissected so far.Here,to identify potential genes controlling C.acetobutylicum biofilm formation,over 40 gene candidates associated with extracellular matrix,cell surface,cell signaling or gene transcription,were tried to be disrupted to examine their individual impact.A total of 25 disruptants were finally obtained over years of attempts,for which biofilm and relevant phenotypes were characterized.Most of these disruptants formed robust biofilm still,or suffered both growth and biofilm defect.Only a strain with a disrupted histidine kinase gene(CA_C2730,designated bfcK in this study)abolished biofilm formation without impairing cell growth or solvent production.Further analysis revealed that bfcK could control flagellar biogenesis and cell motility at protein levels.The bfcK also appeared to repress the phosphorylation of a serine/threonine protein kinase(encoded by CA_C0404)that might negatively regulate biofilm formation.Based on these findings,possible bfcK-mediated mechanisms for biofilm formation were proposed.This is a big step toward understanding the biofilm formation in C.acetobutylicum and will help further engineering of its biofilm-based industrial processes.展开更多
The peroxygenases are ideal biocatalysts for the selective oxyfunctionalisation of stable C-H bonds.However,the catalytic efficiency of this approach is limited due to enzyme lability toward oxidant H_(2)O_(2).Althoug...The peroxygenases are ideal biocatalysts for the selective oxyfunctionalisation of stable C-H bonds.However,the catalytic efficiency of this approach is limited due to enzyme lability toward oxidant H_(2)O_(2).Although the reported in-situ H_(2)O_(2) generation system enables the stable biocatalytic process without deactivating the enzyme,the greatest catalytic potential of peroxygenases still cannot be fulfilled effectively.To address the above issue,a H_(2)O_(2) generation-detection-regulation platform that integrated an effective organocatalyst-driven H_(2)O_(2) generation system,a precise electrochemical H_(2)O_(2) real-time detection device,and a convenient H_(2)O_(2) regulation strategy was first developed.The suitable range of H_(2)O_(2) generation rate for maximizing the catalytic efficiency of peroxygenases while minimizing inactivation of the enzyme was firstly obtained by simply adjusting the amount of organocatalyst.According to the determined suitable range,the C-H oxyfunctionalisation efficiency of peroxygenases for each substrate was significantly boosted,achieving~3-fold of the reported highest turnover frequency.展开更多
基金support by National Key Research and Development Program of China(Grant No.:2023YFA0913604)Program of National Natural Science Foundation of China(Grant No.:22178170,22378195)+2 种基金Six talent peaks project in Jiangsu Province(SWYY-045)Program of National Natural Science Foundation of China(Grant No.22208155)Jiangsu Province Natural Science Foundation for Young Scholars(Grant No.BK20210552).
文摘Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.
基金supported by Jiangsu Province Natural Science Foundation for Distinguished Young Scholars(BK20190035)Jiangsu Government Scholarship for Overseas Studies(JS-2019-053)+6 种基金Key Research&Development plan of Jiangsu Province(BE2019001)the National Natural Science Foundation of China(2217080044 and 22008119)the Natural Science Foundation of Jiangsu Province(BK20202002)the National Key Research and Development Program of China(2021YFC2101204)the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R28)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture.
文摘Adenylate cyclase(AC)is the key enzyme that catalyzes the formation of cAMP from ATP.In this study,we discovered two novel class Ⅲ ACs with a halophilic property from Thermobifida halotolerans DSM 44931(ThAC)and Haloactinopolyspora alba DSM 45211(HaAC),respectively.The recombinant ThAC and HaAC were expressed in Escherichia coli with molecular weights of 36.1 and 36.0 kDa respectively.The presence of 2500 and 2200 mmolL^(-1)1 NaCl significantly enhanced the enzyme activities of ThAC and HaAC,with 22-fold and 7.4-fold higher activities compared to those without NaCl,respectively.Several divalent metal ions were found to activate the recombinant ACs to different extents,and the optimal metal ion was Mg^(2+)for both ThAC and HaAC with concentrations of 80 mmol·L^(-1) and 40 mmol·L^(-1) respectively.Purified ThAC and HaAC had the optimal specific activities((4.59±0.35)×10^(4) and(7.76±0.52)×10^(4) U·mg^(-1))and catalytic efficiency(4.47 and 5.30 L·mmol^(-1)·s^(-1))at 45℃ and 40℃ respectively,while the optimum pH of both two recombinant ACs was 10.0.This is the first report of the halophilic Class III ACs,which could make new contributions to explore and study ACs for further associated investigations.
基金supported by grants from the National Key Research and Development Program of China(2021YFC2102805,2019YFD1101204)the National Natural Science Foundation of China(21878142,21776132)+3 种基金Key Research and Development Plan of Jiangsu Province(BE2020712)Key Research and Development Plan of Jiangsu Province(BE2019001)Jiangsu Natural Science Fund for Distinguished Young Scholars(BK20190035)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.
基金The authors thank the financial support by National Natural Science Foundation of China(21776132,21878142)Jiangsu Province Natural Science Foundation for Distinguished Young Scholars(BK20190035)+2 种基金National Key Research and Development Program of China(2019YFD1101202)Jiangsu Province Natural Science Foundation for Youths(BK20200685)China Postdoctoral Science Foundation(2019M660113).
文摘Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of biocatalysis.These chemoenzymatic methods can not only save resource,cost,and operating time but also reduce the number of reaction steps,and avoid separating unstable intermediates,leading to the generation of more products under greener circumstances and thereby playing an indispensable role in the fields of medicine,materials and fine chemicals.Although incompatible challenges between chemocatalyst and biocatalyst remain,strategies such as biphasic system,artificial metalloenzymes,immobilization or supramolecular host,and protein engineering have been designed to overcome these issues.In this review,chemoenzymatic catalysis according to different chemocatalysis types was classifiably described,and in particular,the classic dynamic kinetic resolutions(DKR)and cofactor regeneration were summarized.Finally,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University(IRT_14R28)the National Basic Research Program of China(2013CB733602)+4 种基金the Major Research Plan of the National Natural Science Foundation of China(21390204)the National Natural Science Foundation of China(21636003,21506090)Open Fund by Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals(JSBGFC14005)Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Microstructure and phase transformation of disodium guanosine 5′-monophosphate(5′-GMPNa_2) are extremely important for controlling the process and understanding the mechanism of crystallization. In this work, the thermodynamic properties of polymorphous 5′-GMPNa_2 especially the solubility were studied, the solubility results show that 5′-GMPNa_2 is more soluble in ethanol–water(E–W) than in isopropanol–water(I–W). The amorphous form of 5′-GMPNa_2 is more soluble than the crystalline form at the same mole fraction and temperature. Meanwhile, the crystalline forms and morphologies of the residual solids were characterized by PXRD and SEM. The results indicate that solid forms of 5′-GMPNa_2 transformed spontaneously from amorphous to crystalline when the ethanol proportion is ≥20%. In addition, increasing the pH facilitates the dissolution of 5′-GMPNa_2 and helps to maintain the crystalline form. The associated Gibbs free energy values were calculated to verify the trend of transformation from amorphous to crystalline 5′-GMPNa_2. These results should help to guide the industrial crystallization process and to obtain the crystalline form of 5′-GMPNa_2.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1066)National Natural Science Foundation of China(No.21306086)Applied Basic Research Programs of Science and Technology Commission Foundation of Jiangsu Province(No.BK20151452)
文摘L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange (DIX) model, which takes the activiW into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest t-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.
基金This work was supported by the Key Program of the National Natural Science Foundation of China(Grant No.21636003)the Outstanding Youth Foundation of Jiangsu(Grant No.SBK2017010373)+1 种基金the National Key Research and Development Program of China(Grant No.2019YFD1101204)the Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture.Dong Liu is supported by the Jiangsu Qinglan Talent Program.
文摘Clostridium acetobutylicum has been extensively exploited to produce biofuels and solvents and its biofilm could dramatically improve the productivities.However,genetic control of C.acetobutylicum biofilm has not been dissected so far.Here,to identify potential genes controlling C.acetobutylicum biofilm formation,over 40 gene candidates associated with extracellular matrix,cell surface,cell signaling or gene transcription,were tried to be disrupted to examine their individual impact.A total of 25 disruptants were finally obtained over years of attempts,for which biofilm and relevant phenotypes were characterized.Most of these disruptants formed robust biofilm still,or suffered both growth and biofilm defect.Only a strain with a disrupted histidine kinase gene(CA_C2730,designated bfcK in this study)abolished biofilm formation without impairing cell growth or solvent production.Further analysis revealed that bfcK could control flagellar biogenesis and cell motility at protein levels.The bfcK also appeared to repress the phosphorylation of a serine/threonine protein kinase(encoded by CA_C0404)that might negatively regulate biofilm formation.Based on these findings,possible bfcK-mediated mechanisms for biofilm formation were proposed.This is a big step toward understanding the biofilm formation in C.acetobutylicum and will help further engineering of its biofilm-based industrial processes.
基金supported by the Program of the National Natural Science Foundation of China(Nos.22178170,22378195 and 22208156)the Six Talent Peaks Project in Jiangsu Province(No.SWYY-045)the Jiangsu Province Natural Science Foundation for Youth(No.BK20200685).
文摘The peroxygenases are ideal biocatalysts for the selective oxyfunctionalisation of stable C-H bonds.However,the catalytic efficiency of this approach is limited due to enzyme lability toward oxidant H_(2)O_(2).Although the reported in-situ H_(2)O_(2) generation system enables the stable biocatalytic process without deactivating the enzyme,the greatest catalytic potential of peroxygenases still cannot be fulfilled effectively.To address the above issue,a H_(2)O_(2) generation-detection-regulation platform that integrated an effective organocatalyst-driven H_(2)O_(2) generation system,a precise electrochemical H_(2)O_(2) real-time detection device,and a convenient H_(2)O_(2) regulation strategy was first developed.The suitable range of H_(2)O_(2) generation rate for maximizing the catalytic efficiency of peroxygenases while minimizing inactivation of the enzyme was firstly obtained by simply adjusting the amount of organocatalyst.According to the determined suitable range,the C-H oxyfunctionalisation efficiency of peroxygenases for each substrate was significantly boosted,achieving~3-fold of the reported highest turnover frequency.