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Weiyi Shao,Wenxian Zhu,Yanhua Wang,Jingwei Lu,Ge Jin,Yixin Wang,Wenli Su 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.1
Human pancreatic trypsin (hPT) is an established target for acute pancreatitis (AP) therapeutics. Here, a bioinformatics protocol of protein docking, peptide refinement, dynamics simulation and affinity analysis was described to perform rational design and molecular engineering of hPT peptide aptamers. Protein docking was employed to model the intermolecular interactions between hPT and its cognate inhibitory protein, the human pancreatic trypsin inhibitor (hTI). A number of peptide fragments were cut out from the interaction sites of docked hPT–hTI complexes, from which a decapeptide fragment 13LNGCTLEYRP22 was found to exhibit potent inhibition against hPT (Ki = 5.3 ± 0.8 μM). We also carried out alanine scanning and virtual mutagenesis to systematically examine the independent contribution of peptide residues to binding affinity, and the harvested knowledge were then used to guide modification and optimization of the decapeptide fragment. Subsequently, inhibition studies of nine promising candidates against recombinant hPT were conducted, from which four samples were successfully identified to have high or moderate potency (Ki < 10 μM). In particular, the peptides LQVCTLEYCN and LQICTLEYCT were found to inhibit hPT activity significantly (Ki = 0.23 ± 0.04 and 0.85 ± 0.18 μM, respectively). Structural analysis of hPT– peptide complex systems unraveled diverse chemical interactions such as hydrogen bonds, salt bridges and hydrophobic forces across the complex interfaces.
Xueqi Shi,Weiyi Su,Hongyu Zhang,Jing Fang,Ning Xu,Yanjun Jiang,Hao Li 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-
Alpha-ketoglutaric acid (a-KG) is a crucial intermediate with broad application prospects. However, thedownstream separation of a-KG from fermentation broth with low concentration and complex componentshas become the bottleneck of large-scale production. In this study, a-KG was separated from theactual fermentation broth by aqueous two-phase system (ATPS) and crystallization. The optimal ATPScomposed of acetone/(NH4)2SO4 was selected by studying the phase diagram and a-KG distributionbehavior in different organic solvents and salts/sugars. Under the optimized conditions, the purity ofa-KG products from crude fermentation broth reached 98.08%, and the one-pass extraction efficiencywas 90.52%. The removal of cell debris and soluble proteins increased with the increase of acetone and(NH4)2SO4 concentrations, with the removal ratios reaching up to 99.44% and 86.54%. In addition,92.56% of the glucose was distributed in the aqueous phase. Although the a-KG fermentation broth ismore complex than the whole-cell biotransformation, impurities in the crude fermentation broth couldbe efficiently removed and a higher a-KG distribution coefficient was obtained. Meanwhile, the recovered(NH4)2SO4 could be reused for fermentation medium. This strategy provides an economical and effectivemethod combined with upstream biosynthesis to recover a-KG and other bioproducts from crude fermentationbroth.
Design and control of extractive distillation for the separation of methyl acetate-methanol-water
Honghai Wang,Pengyu Ji,Huibin Cao,Weiyi Su,Chunli Li 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.12
The azeotrope of methyl acetate methanol and water was isolated using extractive distillation with water as entrainer. The pressure-swing extractive distillation (PSED) process and vapor side-stream distillation column (VSDC) with the rectifier process were designed to separate the methyl acetate, methanol and water mixture. It was revealed that the VSDC with the rectifier process had a reduction in energy consumption than the PSED process. Four control schemes of the two process were investigated: Double temperature control scheme (CS1), QR/F feedforward control of reboiler duty scheme for PESD (CS2), QR/F feedback control scheme for VSDC (CS3), the feedback control scheme of sensitive plate temperature of side-drawing distillation column to dominate the compressor shaft speed (CS4). Feed flow and composition disturbance were used to evaluate the dynamic performance. As a result, CS4 is a preferable choice for separation of methyl acetate-methanol-water mixture. A control scheme combining the operating parameters of dynamic equipment with the control indicators of static equipment was proposed in this paper. It means using the sensitive plate temperature of side-drawing column to control the compressor shaft speed. This is a new control scheme for extractive distillation