title: Protein-Coated Microcrystals from Candida rugosa Lipase: Its Immobilization, Characterization, and Application in Resolution of Racemic Ibuprofen.
abstract: In this study, an economical heterogeneous biocatalyst, protein-coated microcrystals (PCMCs), was prepared from a commercial Candida rugosa lipase (CRL) and used for catalyzing esterification of (R, S)-ibuprofen enantiomers with isooctanol in isooctane. The main variables controlling the process (precipitating solvents, pH, saturated K2SO4 solution, and water content) were optimized via single-factorial experiments. Under optimum conditions, the enantiomeric excess of active S(+)-ibuprofen and total conversion rate were 97.34 and 49.83 %, respectively, and the corresponding enzyme (PCMC-CRL) activity attained 387.29 μmol/min/g protein, a 5.78-fold enhancement over the free lipase powder. Additionally, the thermostability, organic-solvent tolerance, and operational stability of PCMC-CRL were greatly improved as compared to the free enzyme. Fourier transform infrared (FTIR) spectroscopy was employed to reveal the correlation between conformation and enzyme activity enhancement. Moreover, the PCMC-CRL retained most of its original activity following use in more than 15 successive batches, suggesting that it exhibits adequate operational stability. These results indicate that PCMC-CRL is of great potential use in industrial applications.
authors.affiliation: Key Laboratory of Molecular Biophysics, The Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Huang
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Caixia
authors.initials: C
authors.lastname: Ke
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Yunjun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D002175:Candida / Q000201:enzymology*; D003460:Crystallization; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry*; D007052:Ibuprofen / Q000737:chemistry*; D008049:Lipase / Q000737:chemistry* / Q000648:ultrastructure; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism
chemical_list: D004800:Enzymes, Immobilized; D008049:Lipase; D007052:Ibuprofen