As the biodiesel production is rapidly enhanced, the crude glycerol, which is by-product of biodiesel processes, is state of surplus. 1,3-PDO (1,3-propanediol), a valuable monomer of poly(trimethylene terephthalate) (...As the biodiesel production is rapidly enhanced, the crude glycerol, which is by-product of biodiesel processes, is state of surplus. 1,3-PDO (1,3-propanediol), a valuable monomer of poly(trimethylene terephthalate) (PTT), can be produced from the fermentation process using crude glycerin as a carbon source. For the economic biological production of 1,3-PDO, the low cost and high efficient separation processes is essential. In this study, aqueous two-phase system composed of various hydrophilic alcohols and salt was used as a primary separation step for 1,3-PDO. It was found that the aqueous two-phase systems are easily formed with decreasing of the polarity of alcohols. The extraction efficiency is proportional to the polarity of alcohols. In case of methanol or ethanol/K2HPO4, the extraction efficiency was more than 90%.? It was concluded that the aqueous two-phase extraction using methanol or ethanol/K2HPO4 can be applied? for the primary separation of 1,3-PDO? as an alternative to a conventional primary separation processes.展开更多
1,3-Propanediol is a promising renewable resource produced by microbial production. It is mainly used in many synthetic reactions, particularly applied to the polymer synthesis and cosmetics industry. We described her...1,3-Propanediol is a promising renewable resource produced by microbial production. It is mainly used in many synthetic reactions, particularly applied to the polymer synthesis and cosmetics industry. We described here the isolation of strain ZH-1, which has the ability of high production with 1,3-propanediol, from Fenhe River in China. It was classified as a member of K. pneumoniae after the study of phenotypic, physio-logical, biochemical and phylogenetic (16S rDNA). The initial glycerol concentration, fermentation time and pH value of strain ZH-1 were determined to be 50 g·L<sup>-1</sup>, 36 h and 8.0. Under these conditions, the practical yield of 1,3-PD was 18.53 g·L<sup>-1</sup> and a molar yield (mol<sub>1,3-PD</sub> mol<sub>Glycerol</sub>-1</sup> of 1,3-propanediol to glycerol of 0.497. In addition, we found that for the strain ZH-1, the optimum grown pH was 9.0, so we can deter-mine that it is a new member of alkali-resistant strains.展开更多
The natural environment is inhabited by many species that exhibit very specific metabolic activities that may find industrial applications. The aim of the study was to select non-pathogenic cultures of bacteria of the...The natural environment is inhabited by many species that exhibit very specific metabolic activities that may find industrial applications. The aim of the study was to select non-pathogenic cultures of bacteria of the genus Clostridium and lactic acid bacteria able to convert glycerol into 1,3-propanediol (1,3-PD). Another aim of this study was to identify the isolates that best produced 1,3-propanediol both from pure and crude glycerol. The most efficient strains identified (Cl. butyricum) were analysed on a bioreactor scale. The aim was to determine temperature conditions on the efficiency and duration of 1,3-PD synthesis. The species Clostridium were identified using amplification of the 16S rRNA coding sequence. A total of 123 isolates (of the genus Clostridium and lactic acid bacteria) were isolated;a vast majority of these were able to synthesize 1,3-PD. The best results were obtained for Cl. butyricum strain DSP1, which was isolated from the rumen of a cow fed with glycerol. The strain efficiency using pure glycerol on bioreactor scale 0.65 mol/mol of glycerol at a temperature of 38℃ and a constant pH of 7.0.展开更多
The aim of this work was to separate 1,3-PDO from a synthetic mixture using polymeric resins,Amberlite XAD-7 and XAD-16 resins.The equilibrium adsorption of 1,3-PDO onto two polymeric resins were investigated in binar...The aim of this work was to separate 1,3-PDO from a synthetic mixture using polymeric resins,Amberlite XAD-7 and XAD-16 resins.The equilibrium adsorption of 1,3-PDO onto two polymeric resins were investigated in binary and tertiary systems.Experimental results of binary component adsorption equilibrium indicated that the adsorption capacity(q)of 1,3-PDO at 160 g/L onto XAD-7 and XAD-16 was 835.96 and 584.61 mg 1,3-PDO/g dry resin,respectively.The adsorption isotherms were closely predicted by the Langmuir-Freundlich model among the two isotherm model tested.The value of n of 1,3-PDO adsorbed on XAD-7 are much higher than those on XAD-16.This result suggested that XAD-7 resin has a higher affinity for the 1,3-PDO adsorption than XAD-16 resin.Moreover,the value of adsorption capacity of 1,3-PDO in the binary and tertiary component were compared at the same conditions.In the tertiary system,although the selectivity of 1,3-PDO from XAD-7 was approximately six times higher than XAD-16,the adsorption capacity of 1,3-PDO at 160 g/L onto XAD-16 was higher than XAD-7.Interestingly,the reusability of XAD-7 and XAD-16 resins in the three cycle times shows a slight loss of adsorption capacity.Furthermore,the investigation about desorption by an ethanol/water mixture at 50%(V/V)indicated that the desorption yield of 1,3-PDO from XAD-7 was lower than XAD-16 resin for both the binary and tertiary component.This was due to the more favorable adsorption characteristics of XAD-7 resin than XAD-16 resin.展开更多
Based on the combination of the glycerol aqueous-phase reforming(APR)and catalytic hydrogenation of glycerol,a novel reaction system of liquid phase in situ hydrogenation of glycerol for the synthesis of 1,3-propanedi...Based on the combination of the glycerol aqueous-phase reforming(APR)and catalytic hydrogenation of glycerol,a novel reaction system of liquid phase in situ hydrogenation of glycerol for the synthesis of 1,3-propanediol is proposed,in which hydrogen is produced from glycerol aqueous-phase reforming in the same reactor.In this new system,the glycerol is the raw material of the aqueous-phase reforming reaction;the hydrogen generated from the APR of glycerol can be quickly transformed to the in situ hydrogenation of glycerol to produce 1,3-propanediol,which can improve the selectivity of hydrogen for the APR process of glycerol.Moreover,thermodynamic calculation of the coupling processes was carried out,and standard molar enthalpies and equilibrium constants of foregoing reactions were obtained.The above calculation results indicate that the combination process is feasible for 1,3-propanediol synthesis.展开更多
The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol.In this paper,the separation of 1,3-prop...The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol.In this paper,the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investi-gated.The broth was first filtered by ultrafiltration,and 99%of cells,89.4%of proteins and 69%of nucleic acids were removed.The obtained broth was further condensed by vacuum distillation,and then alcohol was added.The macro-molecular impurities,such as nucleic acids,polysaccharides and proteins,were precipitated,and inorganic and organic salts were crystallized.The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1.As a result,proteins,nucleic acids and electric conduc-tivity decreased by 97.4%,89.7%and 95.8%,respectively,compared with the fermentative broth.The influences of pH and water content in condensed broth on alcohol precipi-tation and dilution crystallization were also investigated.The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth.展开更多
【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还...【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还原酶重组大肠杆菌,通过Ni离子亲和层析法纯化得到重组氧化还原酶,以DKTP为底物,考察不同重组氧化还原酶对DKTP的催化活性和选择性,进一步对高选择性酶促合成(S)-DHTP的重组酶CR2进行性质分析,并考察其在最适条件下不对称还原DKTP的过程。【结果】筛选获得产物构型为(S)-型的催化活性最高的酶为CR2,该酶米氏常数Km为0.135 mmol/L,kcat/Km为3.689 L/(mmol·s),最适p H 8.4(0.1 mol/L三乙醇胺缓冲液),最适反应温度为35°C,在10-45°C条件下和p H 7.5-8.5较为稳定,Zn2+离子对酶活有促进作用。CR2催化DKTP不对称还原反应6 h后,DHTP的产率达92.1%、光学纯度达99.9%。【结论】基于活性和选择性分析,获得不对称还原DKTP的目标酶CR2,其催化特性有利于高立体选择性还原DKTP生成度洛西汀中间体(S)-DHTP,从而为进一步提高酶促不对称还原DKTP的转化效率提供研究基础。展开更多
AIM:To determine whether the microRNA-27b-3p(miR-27b-3p)/NF-E2-related factor 2(Nrf2)pathway plays a role in human retinal pigment epithelial(hRPE)cell response to high glucose,how miR-27b-3p and Nrf2 expression are r...AIM:To determine whether the microRNA-27b-3p(miR-27b-3p)/NF-E2-related factor 2(Nrf2)pathway plays a role in human retinal pigment epithelial(hRPE)cell response to high glucose,how miR-27b-3p and Nrf2 expression are regulated,and whether this pathway could be specifically targeted.METHODS:hRPE cells were cultured in normal glucose or high glucose for 1,3,or 6d before measuring cellular proliferation rates using cell counting kit-8 and reactive oxygen species(ROS)levels using a dihydroethidium kit.miR-27b-3p,Nrf2,NAD(P)H quinone oxidoreductase 1(NQO1)and heme oxygenase-1(HO-1)mRNA and protein levels were analyzed using reverse transcription quantitative polymerase chain reaction(RT-qPCR)and immunocytofluorescence(ICF),respectively.Western blot analyses were performed to determine nuclear and total Nrf2 protein levels.Nrf2,NQO1,and HO-1 expression levels by RT-qPCR,ICF,or Western blot were further tested after miR-27b-3p overexpression or inhibitor lentiviral transfection.Finally,the expression level of those target genes was analyzed after treating hRPE cells with pyridoxamine.RESULTS:Persistent exposure to high glucose gradually suppressed hRPE Nrf2,NQO1,and HO-1 mRNA and protein levels and increased miR-27b-3p mRNA levels.High glucose also promoted ROS release and inhibited cellular proliferation.Nrf2,NQO1,and HO-1 mRNA levels decreased after miR-27b-3p overexpression and,conversely,both mRNA and protein levels increased after expressing a miR-27b-3p inhibitor.After treating hRPE cells exposed to high glucose with pyridoxamine,ROS levels tended to decreased,proliferation rate increased,Nrf2,NQO1,and HO-1 mRNA and protein levels were upregulated,and miR-27b-3p mRNA levels were suppressed.CONCLUSION:Nrf2 is a downstream target of miR-27b-3p.Furthermore,the miR-27b-3p inhibitor pyridoxamine can alleviate high glucose injury by regulating the miR-27b-3p/Nrf2 axis.展开更多
A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titana...A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.展开更多
文摘As the biodiesel production is rapidly enhanced, the crude glycerol, which is by-product of biodiesel processes, is state of surplus. 1,3-PDO (1,3-propanediol), a valuable monomer of poly(trimethylene terephthalate) (PTT), can be produced from the fermentation process using crude glycerin as a carbon source. For the economic biological production of 1,3-PDO, the low cost and high efficient separation processes is essential. In this study, aqueous two-phase system composed of various hydrophilic alcohols and salt was used as a primary separation step for 1,3-PDO. It was found that the aqueous two-phase systems are easily formed with decreasing of the polarity of alcohols. The extraction efficiency is proportional to the polarity of alcohols. In case of methanol or ethanol/K2HPO4, the extraction efficiency was more than 90%.? It was concluded that the aqueous two-phase extraction using methanol or ethanol/K2HPO4 can be applied? for the primary separation of 1,3-PDO? as an alternative to a conventional primary separation processes.
文摘1,3-Propanediol is a promising renewable resource produced by microbial production. It is mainly used in many synthetic reactions, particularly applied to the polymer synthesis and cosmetics industry. We described here the isolation of strain ZH-1, which has the ability of high production with 1,3-propanediol, from Fenhe River in China. It was classified as a member of K. pneumoniae after the study of phenotypic, physio-logical, biochemical and phylogenetic (16S rDNA). The initial glycerol concentration, fermentation time and pH value of strain ZH-1 were determined to be 50 g·L<sup>-1</sup>, 36 h and 8.0. Under these conditions, the practical yield of 1,3-PD was 18.53 g·L<sup>-1</sup> and a molar yield (mol<sub>1,3-PD</sub> mol<sub>Glycerol</sub>-1</sup> of 1,3-propanediol to glycerol of 0.497. In addition, we found that for the strain ZH-1, the optimum grown pH was 9.0, so we can deter-mine that it is a new member of alkali-resistant strains.
文摘The natural environment is inhabited by many species that exhibit very specific metabolic activities that may find industrial applications. The aim of the study was to select non-pathogenic cultures of bacteria of the genus Clostridium and lactic acid bacteria able to convert glycerol into 1,3-propanediol (1,3-PD). Another aim of this study was to identify the isolates that best produced 1,3-propanediol both from pure and crude glycerol. The most efficient strains identified (Cl. butyricum) were analysed on a bioreactor scale. The aim was to determine temperature conditions on the efficiency and duration of 1,3-PD synthesis. The species Clostridium were identified using amplification of the 16S rRNA coding sequence. A total of 123 isolates (of the genus Clostridium and lactic acid bacteria) were isolated;a vast majority of these were able to synthesize 1,3-PD. The best results were obtained for Cl. butyricum strain DSP1, which was isolated from the rumen of a cow fed with glycerol. The strain efficiency using pure glycerol on bioreactor scale 0.65 mol/mol of glycerol at a temperature of 38℃ and a constant pH of 7.0.
文摘The aim of this work was to separate 1,3-PDO from a synthetic mixture using polymeric resins,Amberlite XAD-7 and XAD-16 resins.The equilibrium adsorption of 1,3-PDO onto two polymeric resins were investigated in binary and tertiary systems.Experimental results of binary component adsorption equilibrium indicated that the adsorption capacity(q)of 1,3-PDO at 160 g/L onto XAD-7 and XAD-16 was 835.96 and 584.61 mg 1,3-PDO/g dry resin,respectively.The adsorption isotherms were closely predicted by the Langmuir-Freundlich model among the two isotherm model tested.The value of n of 1,3-PDO adsorbed on XAD-7 are much higher than those on XAD-16.This result suggested that XAD-7 resin has a higher affinity for the 1,3-PDO adsorption than XAD-16 resin.Moreover,the value of adsorption capacity of 1,3-PDO in the binary and tertiary component were compared at the same conditions.In the tertiary system,although the selectivity of 1,3-PDO from XAD-7 was approximately six times higher than XAD-16,the adsorption capacity of 1,3-PDO at 160 g/L onto XAD-16 was higher than XAD-7.Interestingly,the reusability of XAD-7 and XAD-16 resins in the three cycle times shows a slight loss of adsorption capacity.Furthermore,the investigation about desorption by an ethanol/water mixture at 50%(V/V)indicated that the desorption yield of 1,3-PDO from XAD-7 was lower than XAD-16 resin for both the binary and tertiary component.This was due to the more favorable adsorption characteristics of XAD-7 resin than XAD-16 resin.
基金The authors acknowledge the financial support of the National High Technology Research and Development Program of China(2009AA05Z444).
文摘Based on the combination of the glycerol aqueous-phase reforming(APR)and catalytic hydrogenation of glycerol,a novel reaction system of liquid phase in situ hydrogenation of glycerol for the synthesis of 1,3-propanediol is proposed,in which hydrogen is produced from glycerol aqueous-phase reforming in the same reactor.In this new system,the glycerol is the raw material of the aqueous-phase reforming reaction;the hydrogen generated from the APR of glycerol can be quickly transformed to the in situ hydrogenation of glycerol to produce 1,3-propanediol,which can improve the selectivity of hydrogen for the APR process of glycerol.Moreover,thermodynamic calculation of the coupling processes was carried out,and standard molar enthalpies and equilibrium constants of foregoing reactions were obtained.The above calculation results indicate that the combination process is feasible for 1,3-propanediol synthesis.
基金supported by the National Basic Research Program of China(“973”project,Grant No.2003CB716000)the Tenth Five-Years’Projects of China Science and Technology Ministry(Grant No.2004BA713B06-03)the National Natural Science Foundation of China(Grant No.20576018).
文摘The separation of 1,3-propanediol from the glycerol-based fermentation broth of Klebsiella pneumoniae plays an important role during the microbial production of 1,3-propanediol.In this paper,the separation of 1,3-propanediol from fermentative broth by a combination of ultrafiltration and alcohol dilution crystallization was investi-gated.The broth was first filtered by ultrafiltration,and 99%of cells,89.4%of proteins and 69%of nucleic acids were removed.The obtained broth was further condensed by vacuum distillation,and then alcohol was added.The macro-molecular impurities,such as nucleic acids,polysaccharides and proteins,were precipitated,and inorganic and organic salts were crystallized.The optimal volume ratio of alcohol added to the condensed fermentation broth was determined to be 2:1.As a result,proteins,nucleic acids and electric conduc-tivity decreased by 97.4%,89.7%and 95.8%,respectively,compared with the fermentative broth.The influences of pH and water content in condensed broth on alcohol precipi-tation and dilution crystallization were also investigated.The experimental results indicated that alcohol precipitation and dilution crystallization was feasible and effective for the separation of 1,3-propanediol from actual fermentation broth.
文摘【目的】通过表达多种重组立体选择性氧化还原酶,分析其催化不对称还原N,N-二甲基-3-酮-3-(2-噻吩)-1-丙胺(DKTP)的性质,从而构建酶促合成(S)-N,N-二甲基-3-羟基-3-(2-噻吩)-1-丙胺(DHTP)的反应体系。【方法】基于已有立体选择性氧化还原酶重组大肠杆菌,通过Ni离子亲和层析法纯化得到重组氧化还原酶,以DKTP为底物,考察不同重组氧化还原酶对DKTP的催化活性和选择性,进一步对高选择性酶促合成(S)-DHTP的重组酶CR2进行性质分析,并考察其在最适条件下不对称还原DKTP的过程。【结果】筛选获得产物构型为(S)-型的催化活性最高的酶为CR2,该酶米氏常数Km为0.135 mmol/L,kcat/Km为3.689 L/(mmol·s),最适p H 8.4(0.1 mol/L三乙醇胺缓冲液),最适反应温度为35°C,在10-45°C条件下和p H 7.5-8.5较为稳定,Zn2+离子对酶活有促进作用。CR2催化DKTP不对称还原反应6 h后,DHTP的产率达92.1%、光学纯度达99.9%。【结论】基于活性和选择性分析,获得不对称还原DKTP的目标酶CR2,其催化特性有利于高立体选择性还原DKTP生成度洛西汀中间体(S)-DHTP,从而为进一步提高酶促不对称还原DKTP的转化效率提供研究基础。
基金Supported by National Natural Science Foundation of China(No.2020J01652)the Training Project for Young and Middleaged Core Talents in Health System of Fujian Province(No.2016-ZQN-62).
文摘AIM:To determine whether the microRNA-27b-3p(miR-27b-3p)/NF-E2-related factor 2(Nrf2)pathway plays a role in human retinal pigment epithelial(hRPE)cell response to high glucose,how miR-27b-3p and Nrf2 expression are regulated,and whether this pathway could be specifically targeted.METHODS:hRPE cells were cultured in normal glucose or high glucose for 1,3,or 6d before measuring cellular proliferation rates using cell counting kit-8 and reactive oxygen species(ROS)levels using a dihydroethidium kit.miR-27b-3p,Nrf2,NAD(P)H quinone oxidoreductase 1(NQO1)and heme oxygenase-1(HO-1)mRNA and protein levels were analyzed using reverse transcription quantitative polymerase chain reaction(RT-qPCR)and immunocytofluorescence(ICF),respectively.Western blot analyses were performed to determine nuclear and total Nrf2 protein levels.Nrf2,NQO1,and HO-1 expression levels by RT-qPCR,ICF,or Western blot were further tested after miR-27b-3p overexpression or inhibitor lentiviral transfection.Finally,the expression level of those target genes was analyzed after treating hRPE cells with pyridoxamine.RESULTS:Persistent exposure to high glucose gradually suppressed hRPE Nrf2,NQO1,and HO-1 mRNA and protein levels and increased miR-27b-3p mRNA levels.High glucose also promoted ROS release and inhibited cellular proliferation.Nrf2,NQO1,and HO-1 mRNA levels decreased after miR-27b-3p overexpression and,conversely,both mRNA and protein levels increased after expressing a miR-27b-3p inhibitor.After treating hRPE cells exposed to high glucose with pyridoxamine,ROS levels tended to decreased,proliferation rate increased,Nrf2,NQO1,and HO-1 mRNA and protein levels were upregulated,and miR-27b-3p mRNA levels were suppressed.CONCLUSION:Nrf2 is a downstream target of miR-27b-3p.Furthermore,the miR-27b-3p inhibitor pyridoxamine can alleviate high glucose injury by regulating the miR-27b-3p/Nrf2 axis.
基金Supported by the National High Technology Research and Development Program of China 863 Plan (Grant No. 2003AA321010) the Innovation Research Fund of Graduate University, Chinese Academy of Sciences (2006)
文摘A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.
