BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2017
·Vol. 40
·期 6
·901-910
·
IF 1.87
Zhang Qiang,Gong Jin-Song,Dong Ting-Ting,Liu Ting-Ting,Li Heng,Dou Wen-Fang,Lu Zhen-Ming,Shi Jin-Song,Xu Zheng-Hong
3-Hydroxypropionic acid (3-HP) is an important platform chemical in organic synthesis. Traditionally, 3-HP was produced by chemical methods and fermentation process. In this work, a novel enzymatic method was developed for green synthesis of 3-HP. A yeast strain harboring nitrile-hydrolyzing enzyme was newly isolated from environmental samples using 3-hydroxypropionitrile (3-HPN) as the sole nitrogen source. It was identified to be Meyerozyma guilliermondii CGMCC12935 by sequencing of the 18S ribosomal DNA and internal transcribed spacer, together with analysis of the morphology characteristics. The catalytic properties of M. guilliermondii CGMCC12935 resting cells were determined, and the optimum activity was achieved at 55 °C and pH 7.5. The enzyme showed broad substrate specificity towards nitriles, especially 3-HPN, aminoacetonitrile and 3-cyanopyridine. The presence of Ag + , Pb 2+ and excess substrate inhibited the enzyme activity, whereas 5% (v/v) ethyl acetate had a positive effect on the enzyme activity. M. guilliermondii CGMCC12935 resting cells by addition of 3% glucose could thoroughly hydrolyze 500 mM 3-HPN into 3-HP within 100 h and the maximal accumulative production of 3-HP reached 216.33 mM, which was over twofolds than the control group with no additional glucose. And this work would lay the foundation for biological production of 3-HP in industry.
研究领域:
生物化学
·
工业微生物学
✓ 已验证
DOI
PubMed
高影响因子
ChemistryOpen
·
2022
·Vol. 11
·期 3
·e202100296
·
IF 2.63
Han Hu,Fangchao Liu,Zhongli Shen,Rui Yan,Zhengwen Fu
Graphical An amorphous selenium graphene composite (a-Se/rGO) and a crystalline selenium nanorods graphene composite (b-Se/rGO) were prepared. Different electrochemical properties of amorphous selenium and selenium nanorods were analyzed. Amorphous selenium shows a good utilization rate in the first discharge, but the utilization rate decreases with the growth of crystals. Selenium (Se) is an element in the same main group as sulfur and is characterized by high electrical conductivity and large capacity (675 mAh g −1 ). Herein, a novel ultra-high dispersion amorphous selenium graphene composite (a-Se/rGO) was synthesized and a selenium nanorods graphene composite (b-Se/rGO) was prepared by hydrothermal method as the cathode material for all solid-state lithium−selenium (Li−Se) batteries, hoping to improve the efficiency and utilization rate of active substances in all solid-state batteries. The all-solid-state batteries were assembled using a heated thawing electrolyte (2LiIHPN−LiI; HPN=3-hydroxypropionitrile). The utilization rate of a-Se/rGO was 103 % and the capacity was 697 mAh g −1 , which remained at 281 mAh g −1 (41.6 % of the 675 mAh g −1 ) after 30 cycles under 0.5 C. Notably, a-Se/rGO showed excellent performance concerning its utilization rate, with a capacity of up to 610 mAh g −1 at 2 C, due to the high availability of amorphous Se and the special properties of the electrolytes. However, in the charge and discharge cycles, the second discharge capacity of a-Se/rGO was more significantly attenuated than that of the first discharge due to the formation of larger crystals of selenium during the charging process. The battery assembled using b-Se/rGO maintained a capacity of 270.58 mAh g −1 after 30 cycles (the retention rate of discharge capacity was 66.13 % compared with that in the first cycle). Through TEM and other relevant tests, it is speculated that amorphous selenium is conducive to capacity release, which, however, is affected by the formation of crystalline selenium after the first charge process.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Electronic Materials
·
2022
·Vol. 9
·期 1
·2200414
·
IF 7.633
Wen Huang,Tianxiong Ju,Ruipeng Li,Yajun Duan,Yanan Duan,Junji Wei,Lei Zhu
High energy density, high temperature, and low loss dielectric polymers have drawn increasing attention in research owing to their potential applications in power electronic and pulsed power devices. In this study, a new class of organo-soluble dipolar glass polymers (DGPs) are synthesized via polycondensation and post-functionalization of poly(aryl ether)s (PAEs) based on phenolphthalin. Due to the nonplanar backbone structure, the strongly dipolar side groups (-SO 2 CH 3 and -CH 2 CH 2 CN) can easily rotate in these PAEs. As a result, desirable physical properties are obtained: high dielectric constant (4.4–5.6), high glass transition temperature (155–180 °C), good mechanical property, and low dielectric loss (dissipation factor < 0.005). Among them, cyanolized poly(aryl ether nitrile) exhibit the highest discharged energy density of 8.6 J cm −3 at 650 MV m −1 and room temperature with a high discharged efficiency of 94.3%. At 100 °C, cyanolized poly(ether ether ketone) shows the highest discharged energy density of 7.3 J cm −3 at 600 MV m −1 with a discharged efficiency of 91%. Furthermore, these functionalized PAEs exhibit good mechanical toughness with a tensile strength at a break of 60-120 MPa and elongation at a break of ≈5%. Based on their thermal, mechanical, and dielectric properties, these phenolphthalin-based PAEs are promising for potential applications such as film capacitors.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
Inorganics
·
2023
·Vol. 11
·期 6
·257
·
IF 2.9
Rui Yan,Fangchao Liu,Zhengwen Fu
Li-SeS2batteries balance the opposing and complimentary qualities of Li-S and Li-Se batteries by having a high specific capacity and high electrical conductivity. However, there is still a lack of knowledge regarding the electrochemical characteristics of Li-SeS2all-solid-state batteries (ASSB). Herein, transmission electron microscopy (TEM) is used to reveal the electrochemistry of a Li-SeS2battery. It is discovered that, without the Polyethylene glycol (PEG), amorphous SeS2in Li-SeS2ASSB change into crystalline selenium and a small amount of sulfur. The continuous loss of sulfur from the active material may be related to the failure of the cell at 15 cycles and the severe instability of the Coulombic efficiency. It was found that the PEG coating selenium disulfide graphene composite (PEG@rGO-SeS2) cathode maintained a specific capacity of 258 mAh g−1and a stable Coulombic efficiency of about 97% after 50 cycles. TEM analysis shows that the charging product remains as a granular amorphous selenium disulfide with a constant Se/S ratio during cycling. The PEG-protected selenium disulfide can effectively limit the loss of elemental sulfur and regulate the reaction mechanism of the Li-SeS2batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）