title: Characteristics of immobilized lipase on hydrophobic superparamagnetic microspheres to catalyze esterification.
abstract: A novel immobilized lipase (from Candida rugosa) on hydrophobic and superparamagnetic microspheres was prepared and used as a biocatalyst to catalyze esterification reactions in diverse solvents and reaction systems. The results showed that the immobilized lipase had over 2-fold higher activities in higher log P value solvents. An exponential increase of lipase activity against log P of two miscible solvent mixtures was observed for the first time. Both free and immobilized lipase achieved its maximum activity at the range of water activity (a(w)) 0.5-0.8 or higher. At a(w) 0.6, the immobilized lipase exhibited markedly higher activities in heptane and a solvent-free system than did the native lipase. In multicompetitive reactions, the alcohol specificity of the lipase showed a strong chain-length dependency, and the immobilized enzyme exhibited more preference for a longer-chain alcohol, which is different from previous reports. The immobilized lipase showed higher specificities for butyric acid and the medium-chain-length fatty acids (C(8)-C(12)). Then, the immobilized lipase was extended to solvent-free synthesis of glycerides from glycerol and fatty acids. Recovered by magnetic separation, the immobilized lipase exhibited good reusability in repeated batch reaction, indicating its promising feature for biotechnology application.
authors.affiliation: Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P. R. China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
mesh_terms: D000327:Adsorption; D000438:Alcohols / Q000737:chemistry*; D002384:Catalysis; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000302:isolation & purification*; D004951:Esterification; D005590:Fractional Precipitation; D005989:Glycerides / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000302:isolation & purification*; D008280:Magnetics; D008863:Microspheres; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D000438:Alcohols; D004800:Enzymes, Immobilized; D005989:Glycerides; D012997:Solvents; D008049:Lipase