title: Enhancing operational stability and exhibition of enzyme activity by removing water in the immobilized lipase-catalyzed production of erythorbyl laurate.
abstract: Erythorbyl laurate was continuously synthesized by esterification in a packed-bed enzyme reactor with immobilized lipase from Candida antarctica. Response surface methodology based on a five-level three-factor central composite design was adopted to optimize conditions for the enzymatic esterification. The reaction variables, such as reaction temperature (10-70°C), substrate molar ratio ([lauric acid]/[erythorbic acid], 5-15), and residence time (8-40 min) were evaluated and their optimum conditions were found to be 56.2°C, 14.3, and 24.2 min, respectively. Under the optimum conditions, the molar conversion yield was 83.4%, which was not significantly different (P < 0.05) from the value predicted (84.4%). Especially, continuous water removal by adsorption on an ion-exchange resin in a packed-bed enzyme reactor improved operational stability, resulting in prolongation of half-life (2.02 times longer compared to the control without water-removal system). Furthermore, in the case of batch-type reactor, it exhibited significant increase in initial velocity of molar conversion from 1.58% to 2.04%/min.
authors: Dept. of Agricultural Biotechnology, Seoul National University, Seoul, 151-742, Republic of Korea.
authors: Da Eun
authors: DE
authors: Lee
authors: Kyung Min
authors: KM
authors: Park
authors: Seung Jun
authors: SJ
authors: Choi
authors: Jae-Hoon
authors: JH
authors: Shim
authors: Pahn-Shick
authors: PS
authors: Chang
mesh_terms: D000327:Adsorption; D055162:Biocatalysis; D019149:Bioreactors; D002175:Candida / Q000201:enzymology; D004800:Enzymes, Immobilized / Q000378:metabolism*; D007848:Laurates / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry / Q000378:metabolism
chemical_list: D004800:Enzymes, Immobilized; D007848:Laurates; D014867:Water; D008049:Lipase
keywords: erythorbyl laurate; immobilized lipase-catalyzed esterification; operational stability; response surface methodology; water removal