title: Ultrasonic pretreatment for lipase-catalyed synthesis of phytosterol esters with different acyl donors.
abstract: This study is focused on the enzymatic esterification of phytosterols with different acyl donors to produce the corresponding phytosterol esters catalyzed by Canadia sp. 99-125 lipase under ultrasound irradiation. An ultrasonic frequency of 35 kHz, power of 200 W and time of 1h was determined to guarantee satisfactory degree of esterification and lipase activity. The influence of temperature, substrates concentration and molar ratio was investigated subsequently. The optimum production was achieved in isooctane system at 60°C with phytosterol concentration of 150 μmol/mL and phytosterol to fatty acid molar ratio of 1:1.5, resulting in a phytosterol esters conversion of above 85.7% in short reaction time (8h). Phytosterols esters could also be converted in high yields to the corresponding long-chain acyl esters via transesterification with triacylglycerols (above 90.3%) under ultrasound irradiation. In optimum conditions, the overall esterification reaction rate using the ultrasonic pretreatment process was above 2-fold than that of mechanical stirring process without damage the lipase activity.
authors.affiliation: Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Hubei Key Laboratory of Oilcrops Lipid Chemistry and Nutrition, Wuhan, China.
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Zheng
authors.forename: Lian
authors.initials: L
authors.lastname: Wang
authors.forename: Feng-Hong
authors.initials: FH
authors.lastname: Huang
authors.forename: Ling
authors.initials: L
authors.lastname: Dong
authors.forename: Ping-Mei
authors.initials: PM
authors.lastname: Guo
authors.forename: Qian-Chun
authors.initials: QC
authors.lastname: Deng
authors.forename: Wen-Lin
authors.initials: WL
authors.lastname: Li
authors.forename: Chang
authors.initials: C
authors.lastname: Zheng
mesh_terms: D055162:Biocatalysis; D004952:Esters / Q000737:chemistry / Q000378:metabolism*; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D010840:Phytosterols / Q000737:chemistry / Q000378:metabolism*; D014465:Ultrasonics
chemical_list: D004952:Esters; D010840:Phytosterols; D008049:Lipase