Nengqiang Wang

Zhejiang University of Technology, Ch’u-chou, Zhejiang Sheng, China

Are you Nengqiang Wang?

Claim your profile

Publications (3)7.03 Total impact

  • Nengqiang Wang · Jun Li · Jing Sun · Jin Huang · Pu Wang
    [Show abstract] [Hide abstract]
    ABSTRACT: We investigated the asymmetric bioreduction of 3,5-bis(trifluoromethyl) acetophenone (BTAP) to (R)-[3,5-bis(trifluoromethyl) phenyl] ethanol ((R)-BTPE) in a hydrophilic quaternary ammonium-based ionic liquid (IL)-containing system to improve the efficiency of bioreduction catalyzed by recombinant Escherichia coli cells overexpressing carbonyl reductase. Based on the low toxicity to microbial cells and moderately increased cell membrane permeability, tetramethylammonium cysteine ([N1,1,1,1][Cys]) was selected and employed as co-solvent. Some key reaction parameters involved in the bioreduction were also investigated in the [N1,1,1,1][Cys]-containing system. The optimum conditions for the process were found to be: 3.5% (w/v) [N1,1,1,1][Cys], 20% (v/v) isopropanol, 1 M BTAP, 12.7 g/L of recombinant E. coli cells, pH 6.8, reaction for 12 h at 30 °C. A 98.7% yield (with >99 % of enantiomeric excess (ee)) was obtained under the optimum conditions. The biocatalytic process was scaled up to a 5 L fermentor afforded high reaction yield in IL-containing system. The results demonstrated that the IL [N1,1,1,1][Cys] is a useful co-solvent to improve bioreduction process and may has potential applications in various biocatalytic reactions.
    No preview · Article · Sep 2015 · Biochemical Engineering Journal
  • Nengqiang Wang · Jin Huang · Hongdou Luo · Pu Wang · Jun Li
    [Show abstract] [Hide abstract]
    ABSTRACT: Leifsonia xyli HS0904 can stereoselectively catalyze the bioreduction of 3,5-bis(trifluoromethyl) acetophenone (BTAP) to its corresponding alcohol, which is a valuable chiral intermediate in the pharmaceuticals. In this study, a new carbonyl reductase derived from L xyli HS0904 was purified and its biochemical properties were determined in detail. The carbonyl reductase was purified by 530-fold with a specific activity of 13.2 U mg(-1) and found to be a homodimer with a molecular mass of 49 kDa, in which the sub-unit molecular-weight was about 24 kDa. The purified enzyme exhibited a maximum enzyme activity at 34 degrees C and pH 7.2, and retained over 90% of its initial activity at 4 degrees C and pH 7.0 for 24h. The addition of various additives, such as Ca2+, Mg2+, Mn2+, L-cysteine,L-glutathione, urea, PEG 1000 and PEG 4000, could enhance the enzyme activity. The maximal reaction rate (V-max) and apparent Michaelis-Menten constant (K-m) of the purified carbonyl reductase for BTAP and NADH were confirmed as 33.9 U mg(-1), 0.383 mM and 69.9 U mg(-1), 0.412 mM, respectively. Furthermore, this enzyme was found to have a broad spectrum of substrate specificity and can asymmetrically catalyze the reduction of a variety of ketones and keto esters. Crown Copyright
    No preview · Article · Aug 2013 · Journal of Molecular Catalysis B Enzymatic
  • Junyao He · Shuai Yuan · Pu Wang · Nengqiang Wang
    [Show abstract] [Hide abstract]
    ABSTRACT: A new bacterial strain, E105, has been introduced as a biocatalyst for the enantioselective hydrolysis of ethyl (R,S)-2-(2-oxopyrrolidin-1-yl) butyrate, (R,S)-1, to (S)-2-(2-oxopyrrolidin-1-yl) butyric acid, (S)-2. This strain was isolated from 60 soil samples using (R,S)-1 as the sole carbon source. The isolate was identified as Tsukamurella tyrosinosolvens E105, based on its morphological characteristics, physiological tests, and 16S rDNA sequence analysis. The process of cell growth and hydrolase production for this strain was then investigated. The hydrolase activity reached its maximum after cultivation at 200 rpm and 30 °C for 36 h. Furthermore, the performance of the enantioselective hydrolysis of (R,S)-1 was studied. The optimal reaction temperature, initial pH, substrate concentration, and concentration of suspended cells were 30 °C, 6.8, 10 and 30 g/l (DCW), respectively. Under these conditions, a high conversion (>45 %) of the product (S)-2 with an excellent enantiomeric excess (ee) (>99 %), and a satisfied enantiomeric ratio (E) (>600) as well were obtained. This study showed that the bacterial isolate T. tyrosinosolvens E105 displayed a high enantioselectivity towards the hydrolysis of racemic ethyl 2-(2-oxopyrrolidin-1-yl) butyrate.
    No preview · Article · May 2012 · Journal of Industrial Microbiology