title: Immobilization of Yarrowia lipolytica lipase Ylip2 for the biocatalytic synthesis of phytosterol ester in a water activity controlled reactor.
abstract: In this work, phytosterol ester was synthesized using Yarrowia lipolytica lipase Ylip2 that had been immobilized on inorganic support in a solvent-free system and reacted in a computer-aided water activity controlled bioreactor. The immobilization of Ylip2 on celite led to a remarkable increase in the phytosterol conversion compared to that of free lipase. An investigation of the reaction conditions were oleic acid as the fatty acid variety, 10,000U/g substrate, and a temperature of 50°C for phytosterol ester synthesis. Controlling of the water activity at a set point was accomplished by the introduction of dry air through the reaction medium at a digital feedback controlled flow rate. For the esterification of phytosterol ester, a low (15%) water activity resulted in a considerable improvement in phytosterol conversion (91.1%) as well as a decreased reaction time (78h). Furthermore, Ylip2 lipase immobilized on celite retained 90% esterification activity for the synthesis of phytosterol oleate after reused 8 cycles, while free lipase was only viable for 5 batches with 90% esterification activity remained. Finally, the phytosterol oleate space time yield increased from 1.65g/L/h with free lipase to 2.53g/L/h with immobilized lipase. These results illustrate that the immobilized Yarrowia lipolytica lipase Ylip2 in a water activity controlled reactor has great potential for the application in phytosterol esters synthesis.
authors.affiliation: National Energy R&D Center for Biorefinery, Beijing Key Laboratory of Bioprocess, College of Biology Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Cui
authors.affiliation: National Energy R&D Center for Biorefinery, Beijing Key Laboratory of Bioprocess, College of Biology Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Guan
authors.affiliation: National Energy R&D Center for Biorefinery, Beijing Key Laboratory of Bioprocess, College of Biology Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Chen
authors.initials: C
authors.lastname: Xing
authors.affiliation: National Energy R&D Center for Biorefinery, Beijing Key Laboratory of Bioprocess, College of Biology Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: chenbq@mail.buct.edu.cn.
authors.forename: Biqiang
authors.initials: B
authors.lastname: Chen
authors.affiliation: National Energy R&D Center for Biorefinery, Beijing Key Laboratory of Bioprocess, College of Biology Science and Technology, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: twtan@mail.buct.edu.cn.
authors.forename: Tianwei
authors.initials: T
authors.lastname: Tan
mesh_terms: D055162:Biocatalysis; D019149:Bioreactors; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D004951:Esterification; D004952:Esters / Q000138:chemical synthesis* / Q000378:metabolism; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism; D010840:Phytosterols / Q000138:chemical synthesis* / Q000378:metabolism; D013379:Substrate Specificity; D014867:Water / Q000737:chemistry*; D025062:Yarrowia / Q000201:enzymology*
chemical_list: D004800:Enzymes, Immobilized; D004952:Esters; D010840:Phytosterols; D014867:Water; D008049:Lipase
keywords: Immobilization; Phytosterol esters; Solvent-free; Water activity; Yarrowia lipolytica lipase