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A novel degradable injectable HLC-HPA hydrogel with antiinflammatory activity for biomedical materials:Preparation,characterization,in vivo and in vitro evaluation

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Science China(Technological Sciences) 2020年第11期63卷 2449-2463页

作者： GAO Shang QU LinLin ZHU ChenHui ouyang pingkai FAN DaiDi Shaanxi Key Laboratory of Degradable Biomedical Materials School of Chemical EngineeringNorthwest UniversityXi’an 710069China Shaanxi R&D Center of Biomaterials and Fermentation Engineering School of Chemical EngineeringNorthwest UniversityXi’an 710069China Biotech&Biomed Research Institute Northwest UniversityXi’an 710069China College of Biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjing 211816China

In situ injectable hydrogels,which have great potential in tissue engineering,are characterized by simple preparation,minimal invasiveness and adaptation to complex ***,injectable hydrogels have higher requirements for biocompatibility and safety due to their use in vivo ***,in this study,a human-like collagen(HLC)-based in situ gel-forming injectable HLC-HPA hydrogel was synthesized by combining the amino group of HLC with the carboxyl group of HPA activated using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride(EDC)and N-hydroxysuccinimide(NHS),followed by crosslinking by horseradish peroxidase(HRP)and H_2O_2,and used as scaffold material for tissue *** hydrogel stiffness,gel time and biodegradation rate could be easily and independently adjusted by varying the H_2O_2 and HRP *** electron microscope(SEM)clarified the homogeneous porous and interconnected internal structures of the *** vitro cell viability and in vivo degradation experiments confirmed that the HLC-HPA hydrogel had good biodegradability and excellent ***,in cultured macrophages,the HLC-HPA hydrogel showed anti-inflammatory activity by reducing the amount of the pro-inflammatory cytokines tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)and increasing the secretion of the anti-inflammatory cytokine interleukin-10(IL-10)induced by lipopolysaccharide(LPS).Meanwhile,in animal experiments,HLC-HPA hydrogels exhibit excellent biocompatibility and have properties of hemostasis and reduction of inflammatory ***,the HLC-HPA hydrogel prepared in this study has great potential for development for use in the biomedical field.

关键词： injectable hydrogels human-like collagen biocompatibility anti-inflammation hemostasis

The influence of the NCO/OH ratio and the 1,6-hexanediol/ dimethylol propionic acid molar ratio on the properties of waterborne polyurethane dispersions based on 1,5-pentamethylene diisocyanate

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Frontiers of Chemical Science and Engineering 2019年第1期13卷 80-89页

作者： Jiao Feng Qiuhao Lu Weimin Tan Kequan Chen pingkai ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University Nanjing 211816 China National Engineering Research Center for Coatings CNOOC Changzhou Paint and Coatings Industry Research Institute Co. Ltd. Changzhou 213016 China

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5-pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transfonn infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffiraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH = 3, HDO/DMPA = 2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU.

关键词： 1,5-pentamethylene diisocyanate polyurethane water based

Recent advance of chemoenzymatic catalysis for the synthesis of chemicals: Scope and challenge

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Chinese Journal of Chemical Engineering 2021年第2期34卷 146-167页

作者： Mengjiao Xu Zhuotao Tan Chenjie Zhu Wei Zhuang Hanjie Ying pingkai ouyang College of Biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjing 211816China

Chemoenzymatic catalysis can give full play to the advantages of versatile reactivity of chemocatalysis and excellent chemo-,regio-,and stereoselectivities of *** 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 *** 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 *** 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 ***,the bottlenecks and development of chemoenzymatic catalysis were summarized,and future development was prospected.

关键词： Chemoenzymatic Dynamic kinetic resolution Cofactor regeneration Biocatalysis Chemocatalysis

The production of enantiopure D-lysine from L-lysine by a two-strain coupled system

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Chinese Journal of Chemical Engineering 2020年第11期28卷 2832-2836页

作者： Sheng Xu Xiaolu Lu Xin Wang Zhen Gao Kequan Chen pingkai ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211816China

The microbial production of D-lysine to replace chemical approach has gained great interest with the rising concerns over the ***,we employed recombinant *** strain BL21-LYR with lysine racemase and strain BL-22A-RB-YB with L-lysine monooxygenase and 5-aminovaleramide amidohydrolase to establish a two-strain coupling whole-cell bioconversion system for D-lysine production from *** improve the optical purity of D-lysine,the optimal reaction condition for resolution of DL-lysine after the racemization was *** specificity of BL-22A-RB-YB for L^-lysine and the effects of reaction condition on bioconversion efficiency of whole-cell were accordingly *** the optimal condition,a maximum 53.5 g·L^-1 D-lysine and 48.2 g·L^-15-AVA were obtained with yield of 47.4%and 42.3%,respectively,by the microbial racemization and asymmetric degradation *** final D-lysine enantiomeric excess was over 99%.Meanwhile,a valuable compound 5-aminovaleric acid was synthesized with the production of D-lysine,indicating the economic feasibility of the two-strain coupling system.

关键词： _D-Lysine Microbial resolution Two-strain coupling system

Combination of ARTP mutagenesis and color-mediated highthroughput screening to enhance 1-naphthol yield from microbial oxidation of naphthalene in aqueous system

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Frontiers of Chemical Science and Engineering 2020年第5期14卷 793-801页

作者： Chenggang Qiu Alei Zhang Sha Tao Kang Li Kequan Chen pingkai ouyang College of Biotechnology and Pharmaceutical Engineering Nanjing Tech UniversityNanjing 211800China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing Tech UniversityNanjing 211800China

Strain QCG of the aerobic bacteria Bacillus cereus is capable of producing l-naphthol from naphtha-lene,this strain was first isolated and characterized in this *** QCG was mutagenized to enhance l-naphthol production,using atmospheric and room temperature plasma(ARTP)***,a microbial clone screening system was used to accelerate the ***,a novel color-mediated high-throughput screening using 4-aminoantipyrine was performed to screen *** optimal mutant strain QCG4 produced 19.58土0.34 mg·L-1-naphthol from naphthalene that was 47.32%higher than that of the original strain(13.29+0.28 mg·L-1).In addition,the optimal conditions for l-naphthol production via whole-cell catalysis of strain QCG4 were determined to be an OD600 of40,150 mg.L I naphthalene,and 7.5%dimethyl formamide as a co-solvent at pH 7.5 and 26℃ for 3 h,resulting in 41.18士0.12 mg·L-l-naphthol,i.e.,the mutant strain produces a 2.1-fold higher yield compared to the original strain.

关键词： Bacillus cereus QCG naphthalene 1-naphthol ARTP mutagenesis high-throughput screening 4-aminoan-tipyrine

Characterization and application of a recombinant dopa decarboxylase from Harmonia axyridis for the efficient biosynthesis of dopamine

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Chinese Journal of Chemical Engineering 2022年第1期35卷 449-456页

作者： Siyuan Gao Yuanke Guo Chen Ma Ding Ma Kequan Chen pingkai ouyang Xin Wang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211816China

Here,a dopa decarboxylase(DDC)from Harmonia axyridis was heterogeneously expressed in Escherichia coli for the efficient biosynthesis of *** the production of recombinant DDC,the cultivation conditions including IPTG concentration,temperature and induction time were optimized and obtained an optimal specific enzyme activity of 51.72 U·mg^(-1) crude *** the purification of DDC with a recovery yield of 68.79%,its activity was further *** Vmax,Km,Kcat,and Kcat/Km of DDC for d ihyd roxy pheny la la nine(dopa)were 0.02 mmol·ml^(-1)·s^(-1),2.328 mmol·ml^(-1),10435.90 s^(-1) and4482.77 ml,mmol *** highest DDC activity was observed at the condition of pH 7.5 and 45℃.With the purified DDC,the feasibility to produce dopamine from L-dopa was *** optimal yield was determined at the following bioconversion conditions:pH of 7,0,the reaction temperature of 40℃,0.4 mmol·L^(-1) of PLP and 4 g·L^(-1) of L-dopa,Subsequently,a fed-batch process for the production of dopamine was developed and the effect of oxygen was *** titer,yield and productivity of dopamine reached up to 21.99 g·L^(-1)80.88%and 14.66 g·L^(-1)·h^(-1) at 90 min under anaerobic condition.

关键词： Dopa decarboxylase Dopamine Enzyme catalysis Fed-batch bioconversion

The production of biobased diamines from renewable carbon sources: Current advances and perspectives

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Chinese Journal of Chemical Engineering 2021年第2期34卷 4-13页

作者： Xin Wang Siyuan Gao Jing Wang Sheng Xu Hui Li Kequan Chen pingkai ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing 211816JiangsuChina Zhejiang Zhongshan Chemical Industry Group Co.Ltd Huzhou 313100Chin

Bio-based diamines are considered to be a promising alternative to traditional fossil-fuel-based diamines,the important platform chemical for the synthesis of polymer *** this review,the current status of the art of the synthesis of aliphatic and aromatic diamines from renewable biomass are *** the case of aliphatic diamines,we describe strategies for biologically producing diamines with different carbon numbers including 1,3-diaminopropane,1,4-butanediamine,1,5-pentanediamine,1,6-diaminohexane,1,8-diaminooctane,1,10-diaminodecane,and 1,*** addition,aromatic diamines produced from various kinds of renewable biomass,including lignin,cashew nut shell,and terpenoids,are reviewed ***,the application of typical diamines in synthesis of polyurethane and polyamide are also reviewed.

关键词： Aliphatic diamines Aromatic diamines Polyamide Polyurethane

Advances in Cadaverine Bacterial Production and Its Applications

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Engineering 2017年第3期3卷 308-317页

作者： Weichao Ma Kequan Chen Yan Li Ning Hao Xin Wang pingkai ouyang State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing Tech University Nanjing 211816 China College of Biotechnology and Pharmaceutical Engineering Nanjing Tech University Nanjing 211816 China College of Bioengineering and Biotechnology Tianshui Normal University Tianshui 741001 China

Cadaverine. a natural polyamine with multiple bioactivities that is widely distributed in prokaryotes and eukaryotes, is becoming an important industrial chemical. Cadaverine exhibits broad prospects for various applications, especially as an important monomer for bio-based polyamides. Cadaverine-based polyamide PA 5X has broad application prospects owing to its environmentally friendly characteristics and exceptional performance in water absorption and dimensional stability. In this review, we summarize recent findings on the biosynthesis, metabolism, and physiological function of cadaverine in bacteria, with a focus on the regu- latory mechanism of cadaverine synthesis in Escherichia coil （E. coli）. We also describe recent developments in bacterial production of cadaverine by direct fermentation and whole-cell bioconversion, and recent approaches for the separation and purification of cadaverine. In addition, we present an overview of the ap- plication of cadaverine in the synthesis of completely bio-based polyamides. Finally. we provide an outlook and suggest future developments to advance the production of cadaverine from renewable resources.

关键词： Cadaverine Metabolism Bacterial production Bio-polyamide PA 5X

Engineering the native methylotrophs for the bioconversion of methanol to value-added chemicals:current status and future perspectives

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Green Chemical Engineering 2023年第2期4卷 199-211页

作者： Jing Wang Ruirui Qin Yuanke Guo Chen Ma Xin Wang Kequan Chen pingkai ouyang State Key Laboratory of Materials-Oriented Chemical Engineering College of Biotechnology and Pharmaceutical EngineeringNanjing Tech UniversityNanjing211816China

Methanol is becoming an attractive fermentation feedstock for large-scale bioproduction of chemicals,due to its natural abundance and mature production *** methylotrophs,which can utilize methanol as the only source of carbon and energy,are ideal hosts for methanol bioconversion due to their high methanol utili-zation rate and have been extensively employed in the production of value-added chemicals from ***,we review the natural methanol utilization pathways in native methylotrophs,describing the available synthetic biology tools developed for engineering native methylotrophs,and discuss the strategies for improving their methanol utilization ***,the representative examples of engineering the native methylotrophs to produce value-added products from methanol are ***,we also discuss the major challenges and possible solutions for the application of native methylotrophs in methanol-based biomanufacturing.

关键词： Native methylotrophs Methanol Biomanufacturing Value-added chemicals