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Solubilities of Calcium and Zinc Lactate in Water and Water - Ethanol Mixture
Cao, Xue Jun,Lee, Ho Joon,Yun, Hyun Shik,Koo, Yoon Mo 한국화학공학회 2001 Korean Journal of Chemical Engineering Vol.18 No.1
The solubility of lactate salts, L(+) and DL( ±) forms of calcium and zinc lactate in water at temperature between 5 and 80℃, was measured and empirical equations were obtained by regression of solubility-temperature data. The equations can be used to calculate the solubility of calcium and zinc lactate at a given temperature. The change in solubility of L(+) and DL( ±) calcium and zinc lactate in water-ethanol mixture at 20℃ was also investigated. The solubilities of calcium and zinc lactate were lowered by the addition of ethanol to the solution.
( Xue Jun Cao ),( Jian Hua Zhou ),( Zhen Hui Huang ),( Xing Yan Wu ),( Byung Ki Hur ) 한국미생물 · 생명공학회 2002 Journal of microbiology and biotechnology Vol.12 No.2
A novel process for urokinase purification was studied using p-aminobenzamidine as the ligand and sepharose 4B as the matrix. The adsorption, washing, and elution conditions were optimized by an unusual method. An adsorption buffer containing 2.5 M NaCl and 1% Tween 80 facilitated the adsorption of urokinase on the affinity media and prevented contaminants from binding to the p-aminobenzamidine affinity gel. It was found that 5% Tween 80 removed most of the contaminants from the affinity column. A 0.2 M glycine elution buffer containing 0.5 M NaCl (pH 3.0) was found to have a strong elution ability with a high recovery and purity of urokinase. A crude urokinase material of 231 IU/mg protein from human urine was purified to 124,300 IU/mg protein with a purification factor of 538 and yield of 86.7%. As a result, a high purity urokinase was obtained with only a single affinity chromatography step. The purification process was successfully scaled-up to a 2-1 chromatography column. The resulting urokinase eluate could be directly lyophilized, thereby complying with Chinese pharmacopoeia (1995 version) standards.
Biodegradation of Cellulose by β-glucosidase and Cellulase Immobilized on a pH-responsive Copolymer
Jingjing Liu,Xue-Jun Cao 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5
Biodegradation of cellulose involves synergisticaction of the endoglucanases, exoglucanases and β-glucosidases in cellulase. However, the yield of glucose islimited by the lack of β-glucosidase to hydrolyze cellobioseinto glucose. In this study, β-glucosidase as a supplementalenzyme along with cellulase are co-immobilized on a pHresponsivecopolymer, poly (MAA-co-DMAEMA-co-BMA)(abbreviated PMDB, where MAA is α-methacrylic acid,DMAEMA is 2-dimethylaminoethyl methacrylate and BMAis butyl methacrylate). The thermal and storage stabilitiesof PMDB with immobilized enzymes are improved greatly,compared with those of free cellulase. Biodegradation ofcellulose is carried out in a pH-responsive recyclableaqueous two-phase system composed of poly (AA-co-DMAEMA-co-BMA) (abbreviated PADB 3.8, where AA isacrylic acid) and PMDB. Insoluble substrate and PMDB withimmobilized cellulase and β-glucosidase (Celluclast 1.5LFG and Novozyme 188, respectively) were biased to thebottom phase, while the product was partitioned to the topphase in the presence of 40 mM (NH4)2SO4. When thedegradation reaction of cellulose is carried out with PMDBcontaining immobilized cellulase and β-glucosidase, theconcentration of glucose reaches 4.331 mg/mL after 108 h. The yield of glucose is 50.25% after PMDB containing theimmobilized enzymes is recycled five times.
Synthesis of Cefprozil Using Penicillin G Acylase in Recyclable Aqueous Two-phase Systems
Chaohui Zhu,Xue-Jun Cao 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5
Cefprozil is an important semi-syntheticcephalosporin antibiotic. In this study, immobilized penicillinG acylase (PGA) is used to catalyze the acylation of 7-amino-3-(1-propenyl)-4-cephalosporanic acid (7-APRA)and 4-hydroxyphenylglycine methyl ester (HPGME) and arecyclable thermo-pH responsive PNB/PADB aqueous twophasesystem (ATPS) is used to synthesize cefprozil. In thissystem, the partition coefficient of cefprozil was 2.24 with60 mmol/L (NH4)2SO4. In addition, the optimal enzymaticreaction conditions were found to be pH 6.5, 20°C, 78 u/mLimmobilized PGA, 30 mmol/L 7-APRA and 90 mmol/LHPGME. In the PNB/PADB ATPS, the maximal yield ofcefprozil was 75.81% with 60 mmol/L (NH4)2SO4 and inthe single aqueous system the yield was 56.02%. Theyields are thought to improve because there is a reductionin product inhibition.
Hao, Liu-Ping,Cao, Xue-Jun,Hur, Byung-Ki Elsevier 2008 Journal of industrial and engineering chemistry Vol.14 No.5
<P><B>Abstract</B></P><P>The importance of polyunsaturated fatty acids (PUFAs) in human nutrition and disease prevention was demonstrated four decades ago. EPA and DHA are important PUFAs. Separation of EPA and DHA has been carried out under supercritical condition by using a silver ion modified molecular sieve 13X (MS13X). MS13X was modified by silver nitrate, and the modification reaction was optimized by stir model, the concentration of silver nitrate and temperature. It was found that the optimized reaction conditions are stirring with nitrogen bubbling, 0.1mol/l silver nitrate and 20°C in the dark. Results indicated that 1g MS13X could be bound by 7.4mg silver ion, namely 12.4% sodium of MS13X was exchanged. The modified MS13X (called SN13X) displays maximum adsorption capacity of EPA and DHA at 40°C, with 37.4mg/g and 24.2mg/g, respectively. SN13X was packed in the column (20cm×1cm) under supercritical fluid apparatus, and adsorption, washing and elution of EPA and DHA were carried out by gradient pressure. In this study, the purity of EPA and DHA were enhanced to 88.4% and 84.3% from 20.4% and 12.7%, with recovery of 45.8% and 39.2%, respectively.</P>
Zhaoyang Ding,Kai Zheng,Xue-Jun Cao 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.5
A thermo-responsive polymer (PNNB) wassynthesized with lower critical solution temperature 27.5ºCand over 95% recovery. The adsorption of porcine pancreaticlipase on Cibacron Blue F3GA-conjugated PNNB (PNNBCB)closely followed the bi-Langmuir adsorption isotherm. The maximum adsorption capacity was found at pH 5.0,with a ligand density of 18.4 μmol/g polymers. Theoptimized eluent was a 0.01 M phosphate buffer solution atpH 8.0 containing 20% ethylene glycol. Six adsorptiondesorptionrecycles indicated excellent reusability of theaffinity adsorbent. PNNB-CB was applied to separate porcinepancreatic lipase from its crude material giving a lipaseactivity recovery of 81.6% with a 16-fold purificationfactor. Lipase could be purified to single-band purity,according to gel electrophoresis. The purification strategyis therefore feasible and efficient for purifying proteins ofinterest.