title: Enzymatic dipeptide synthesis by surfactant-coated alpha-chymotrypsin complexes in supercritical carbon dioxide.
abstract: Enzymatic dipeptide synthesis by surfactant-coated alpha-chymotrypsin complexes was performed in supercritical CO(2) and liquid CO(2) at 308.2 and 333.2 K at pressures of 6.1 and 10.1 MPa. The enzymatic activity of coated alpha-chymotrypsin complexes for dipeptides synthesis at 10.1 MPa in supercritical CO(2) (SC-CO(2)) was higher than that in a liquid CO(2) and ethyl acetate solution at 6.1 MPa. The behavior of alpha-chymotrypsin in SC-CO(2) was similar to that in liquid ethyl acetate. And increasing the pressure and temperature increased the maximum conversion and the enzymatic reaction rate in SC-CO(2). Furthermore, the control of the water content in the reaction media had a dominant effect on the enzymatic activity. The maximum conversion for the dipeptide synthesis by the surfactant-coated alpha-chymotrypsin was obtained at 4% water content. The alpha-chymotrypsin complexes exhibited a higher enzymatic activity than native alpha-chymotrypsin in SC-CO(2). The nonionic surfactants l-glutamic acid dialkyl ester ribitol amide and sorbitan monostearate were more favored than the anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate.
authors.affiliation: Department of Chemical Engineering, Faculty of Engineering, and Advanced Materials Institute, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan. mishima@fukuoka-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Mishima
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsuyama
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Baba
authors.forename: Masuhiro
authors.initials: M
authors.lastname: Chidori
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry*; D002384:Catalysis; D002918:Chymotrypsin / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D004151:Dipeptides / Q000138:chemical synthesis*; D004789:Enzyme Activation; D044367:Phase Transition; D011312:Pressure; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013379:Substrate Specificity; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D020099:Coated Materials, Biocompatible; D004151:Dipeptides; D012997:Solvents; D013501:Surface-Active Agents; D002245:Carbon Dioxide; D002918:Chymotrypsin; C117608:alpha-chymotrypsin