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Zhimin Ou,Xiaoyan Chen,Guoqing Ying,Hanbing Shi,Xingyuan Sun 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2
In this study, (S)-3-hydroxy-3-phenylpropionate was prepared continuously by coupling microbial transformation and membrane separation. The effect of several factors on membrane flux, reactor capacity, and reaction conversion were investigated. A kinetic model of the continuous reduction process was also developed. The appropriate molecular weight cut-off of the ultrafiltration membrane was 30 kDa. The reactor capacity reached a maximum of 0.136/h at a biomass concentration and membrane flux of 86 g/L (dry weight/reaction volume) and 20 mL/h, respectively. The (S)-3-hydroxy-3-phenylpropionate yield was 3.68 mmol/L/day after continuous reduction over seven days. The enantiometric excess of (S)-3-hydroxy-3-phenylpropionate reached above 99.5%. The kinetic constants of continuous reduction were as follows:r_m = 3.00 × 10^(−3) mol/L/h, k_(cat) = 3.49 × 10^(−4) mol/L/h, k_1 =3.09 × 10^(−2) mol/L, and k_2 = 5.00 × 10^(−7) mol/L. The kinetic model was in good agreement with the experimental data obtained during continuous reduction. Compared with batch reduction, continuous reduction can significantly improve the catalytic efficiency of microbial cells and increase the reactor capacity.
Jiaying Pan,Zhimin Ou,Lan Tang,Hanbing Shi 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.5
Racemic 1-phenylethylamine was resolved by enantiomer selective acetylation using Fe3O4-chitosan microsphere (CTS)-glutaraldehyde-lipase in a solvent-free system under an alternating magnetic field. Magnetic chitosan microspheres (Fe3O4-CTS) were prepared via chemical co-precipitation and cross-linked with lipase using glutaraldehyde to form Fe3O4-CTS-glutaraldehyde-lipase particles. The magnetic, physicochemical, and textural characteristics of Fe3O4-CTS-glutaraldehyde-lipase particles were assessed by Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The optimal immobilization conditions were 2.4mg/mL lipase, 10mg/mL Fe3O4- CTS-glutaraldehyde, pH 8.5, 35 oC, 3 h. The loading amount of lipase and the specific activity got to 132mg/g carrier and 48U/g. The optimal reaction conditions of the acylation reaction using Fe3O4-CTS-glutaraldehyde-lipase were 300mmol/L 1-phenylethylamine, 150mg immobilized lipase, 2mL vinyl acetate, 12.6 ×g rotating speed, 40 oC, 8 h. The activity of the Fe3O4-CTS-glutaraldehyde-lipase particles and conversion were improved when they were exposed to an external alternating magnetic field. The optimum magnetic field was 12 Gs (500 Hz). The conversion, enantiomeric excess of (R)-N-(1-phenylethyl)acetamide, and E value reached 41.8%, 98.4%, and 264, respectively. Fe3O4-CTS-glutaraldehyde- lipase could be reused seven times. A kinetic model of the immobilized lipase-catalyzed resolution of 1- phenylethylamine was set up based on the ping-pong bi–bi mechanism. The kinetic constants were Vmax=1.62×102 mM/min, KA=2.84×104mM, and KB=5.8×101mM. The model data fit well with the experimental data.
Bi Hongxia,Sun Xingyuan,Shi Hanbing,Ou Zhimin 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1
Tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate was synthesized using asymmetric reduction of tertbutyl (S)-6-chloro-5-hydroxy-3-oxo-hexanoate with liquid-core immobilized Saccharomyces cerevisiae CGMCC No. 2233. The optimum conditions for preparation of the liquid-core immobilized cells were found to be 2% guar gum,5% CaCl2, 0.8% sodium alginate, capsule diameter 2mm, 0.3% chitosan (1.0×105) solution, and 30 min for formation of the film of liquid-core immobilized cells. The optimum re-cultivation time was 32 h. The optimum reduction conditions were found to be pH 6.8-7.2, 160 r/min, and 30 oC. Conversion was found to reach 100% when initial concentration of substrate was less than 50 g/L. The diastereomeric excess of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate exceeded 99%. The liquid-core immobilized cells retained their effectiveness even after 15 uses.
Jia Fu,Yuejiang Shi,Yingying Li,Fudi Wang,Sheng Liu,Jian Zhang,Jun Li,Yiyyun Huang,Yuanlai Xie,Zhimin Liu,Chundong Hu,Chundong Hu,DNB Team,William Rowan,He Huang 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.5
A diagnostic neutral beam (DNB) has been installed on the HT-7 tokamak for the measurement of charge exchange recombination spectroscopy (CXRS). The H_α-light Doppler shift spectroscopy from the drifted duct is measured to determine the components of the neutral beam. The fractions of neutral beam species are investigated under a wide range of arc voltages and extraction high voltages of the beam aimed to the optimized species fractions for the CXRS applications. A magnet ring is used to improve the magnetic property of the ion source. The result shows that the full-energy component fractions increase from 19 to 25 percent with optimization of the beam operation, but with a dramatic increase of the water component. There are nine optical fiber channels observing one section of the beam simultaneously for this spectroscopy, which provides information of the power profiles of the beam. The full width at half maximum (FWHM) of the beam profile is 8 cm, as measured by using the spectroscopy.
Yuan Lu,Hongqian Dai,Pengpeng Cheng,Hanbing Shi,Lan Tang,Xingyuan Sun,Zhimin Ou 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.5
A modular approach was applied for the synthesis of bienzyme-polymer nanoconjugates (nano-BECs) (50- 70 nm) consisting of two enzymes (carbonyl reductase and glucose dehydrogenase) conjugated within a single universal polymer scaffold. The amount of the product ethyl (R)-2-hydroxy-4-phenylbutyrate (R-HPBE) with nano-BECs as the catalyst was 533mM in a dibutyl phthalate-phosphate buffer (dibutyl phthalate-PB) biphasic system, while the amount of R-HPBE was 349mM using carbonyl reductase-poly(acrylic acid) as the catalyst, indicating that the nano- BECs have an advantage for coenzyme regeneration. Compared with a single aqueous phase, the substrate treatment capacity was improved at the interface of the dibutyl phthalate-PB biphasic system. Under the optimal reaction conditions (35 oC, 40 h, dibutyl phthalate-PB 1 : 1), nano-BECs can completely convert substrate into optically pure R-HPBE (enantiomeric excess (e.e.) >99.9%) in the organic-aqueous system.