title: Assessment of activities and conformation of lipases treated with sub- and supercritical carbon dioxide.
abstract: In order to illustrate the underlining mechanism of the effect of high pressure on lipases from different resources, the influence of compressed carbon dioxide treatment on the esterification activities and conformation of the three lipases Candida rugosa lipase (CRL), Pseudomonas fluorescens lipase, and Rhizopus oryzae lipase was investigated in the present work. The results showed that the lipases activities were significantly enhanced in most of high-pressure treatments, except the pressure had a negative effect on CRL activity in supercritical condition. Mild depressurization rate could remain the lipase's activity by protecting its rigid structure under supercritical fluid. Conformational analysis by Fourier transform-infrared spectrometry and fluorescence emission spectra revealed that the variances of lipase activity after high-pressure treatment were correlated with the changes of its α-helix content and fluorescence intensity. Additionally, transesterification catalyzed by three lipases in supercritical carbon dioxide were conducted, and 87.2 % biodiesel conversion was obtained by CRL after 3 h, resulting in a great reduction of reaction time.
authors: Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, Peoples Republic of China. cdw378@qq.com
authors: Dawei
authors: D
authors: Chen
authors: Cheng
authors: C
authors: Peng
authors: Houjin
authors: H
authors: Zhang
authors: Yunjun
authors: Y
authors: Yan
mesh_terms: D002175:Candida / Q000201:enzymology; D002245:Carbon Dioxide / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism*; D011551:Pseudomonas fluorescens / Q000201:enzymology; D012233:Rhizopus / Q000201:enzymology; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002245:Carbon Dioxide; D008049:Lipase