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Isolation of L-theanine from Tea Solution by Cation Exchange Resin in Batch and Fixed Bed Column
Jian-Hui Ye,Yi-Wen Luo,Hui-Ling Liang,Jian-Liang Lu,Jing Jin,Yue-Rong Liang,Xin-Qiang Zheng,Xian-Yang Luo 한국생물공학회 2011 Biotechnology and Bioprocess Engineering Vol.16 No.2
L-Theanine, a bioactive compound in tea, was isolated from tea solution using cation exchange resin no.732. The adsorption of L-theanine by cation exchange resin no.732 fit the Langmuir isotherm model and was a monolayer molecular interaction process. Thermodynamic studies revealed that the adsorption of L-theanine by resin no.732 was an exothermic and spontaneous physically driven process. The adsorption capacity was influenced by temperature, initial concentration, and pH. The L-theanine adsorption capacity under conditions at room temperature,pH 4.73, and initial L-theanine concentration 18 g/L was 241.731 ± 3.679 mg/g. The Thomas model was fit to describe the column adsorption data at different flow rates and initial concentrations. The L-theanine adsorbed by resin no.732 could be desorbed by 0.134 mol/L Na2HPO4aqueous solution with a recovery rate of 84.96%. These findings indicate that resin no.732 was a promising material for isolating L-theanine from tea solution.
Jian-Rong Wu,Jin-Long Liu,Xiao-Bei Zhan,Chi-Chung Lin,Hui Zhao 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.4
Polysialic acid (PSA) is a capsular polysaccharide obtained from aerobic fermentation with Escherichia coli. To enhance PSA production and eliminate the influence of phosphate on the PSA purification process, a lower level of initial phosphate was adopted with pH control. The resulting PSA yield reached 4.1 g/L in fed-batch fermentation with 2.5 g/L K2HPO4 and E. coli strain CCTCC M208088. In addition, an ammonia water (NH4OH) feeding strategy to control the pH at 6.4 was developed resulting in PSA production that reached as high as 5.2 g/L. NMR spectra confirmed the purified biopolymer as a α-2,8linked PSA, identical to the published NMR spectra, with a molecular weight in the range of 16 ~ 50 kDa.
Jian-Rong Peng,Hsin-Fu Lee,Chi-Jen Chang,Chun-Li Wang,Ying-Chang Tung 대한심장학회 2017 Korean Circulation Journal Vol.47 No.1
Background and Objectives: The aim of this study was to identify clinical, lesional, and procedural predictors for adverse outcomes of coronary angioplasty and stenting in coronary bypass candidates. Subjects and Methods: This cohort study included 107 consecutive candidates for coronary artery bypass surgery who underwent percutaneous coronary intervention with multiple coronary stents between Jan 2004 and Dec 2011. The study endpoint was major adverse cardiovascular events (MACEs) including all-cause mortality, nonfatal myocardial infarction, repeat revascularization, and stent thrombosis. Follow up was from the date of index percutaneous coronary intervention to the date of the first MACE, date of death, or December 31, 2015, whichever came first. Results: In this study (age 62.3±11.2 years, 86% male), 38 patients (36%) had MACE. Among baseline, angiographic, and procedural parameters, there were significant differences in lower left ventricular ejection fraction (LVEF) and worse renal function. In a Cox regression model, LVEF and chronic kidney disease (CKD) were significant predictors for MACE. After a multivariate adjustment, CKD remained a significant predictor of MACEs (hazard ratio: 2.97, 95% confidence interval: 1.50-5.90). Conclusions: For coronary bypass candidates who were treated with coronary angioplasty and stenting, CKD seems to be the strongest predictor for adverse outcomes compared with other traditional factors.
( Jian Rong Xue ),( Hong Zhong ),( Shuai Wang ),( Chang Xin Li ),( Jin Zhong Li ),( Fang Fang Wu ) 한국화학공학회 2015 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.53 No.4
We investigated the reduction leaching process of manganese dioxide ore using black locust as reductant in sulfuric acid solution. The effect of parameters on the leaching efficiency of manganese was the primary focus. Experimental results indicate that manganese leaching efficiency of 97.57% was achieved under the optimal conditions: weight ratio of black locust to manganese dioxide ore (WT) of 4:10, ore particle size of 63 μm, 1.7 mol·L-1 H2SO4, liquid to solid ratio (L/S) of 5:1, leaching time of 8 h, leaching temperature of 368 K and agitation rate of 400 r·min-1. The leaching rate of manganese, based on the shrinking core model, was found to be controlled by inner diffusion through the ash/inert layer composed of associated minerals. The activation energy of reductive leaching is 17.81 kJ·mol-1. To conclude the reaction mechanism, XRD analysis of leached ore residue indicates manganese compounds disappear; FTIR characterization of leached residue of black locust sawdust shows hemicellulose and cellulose disappear after the leaching process.