title: Optimization of lipase-catalyzed synthesis of ginsenoside Rb1 esters using response surface methodology.
abstract: In the lipase (Novozyme 435)-catalyzed synthesis of ginsenoside Rb1 esters, different acyl donors were found to affect not only the degree of conversion but also the regioselectivity. The reaction of acyl donors with short carbon chain was more effective, showing higher conversion than those with long carbon chain. Among the three solvent systems, the reaction in tert-amyl alcohol showed the highest conversion rate, while the reaction in the mixed solvent of t-BuOH and pyridine (1:1) had the lowest conversion rate. To allow the increase of GRb1 lipophilicity, we decided to further study the optimal condition of synthesis of GRb1 with vinyl decanoate with 10 carbon chain fatty acids in tert-amyl alcohol. Response surface methodology (RSM) was employed to optimize the synthesis condition. From the ridge analysis with maximum responses, the maximum GRb1 conversion was predicted to be 61.51% in a combination of factors (40.2 h, 52.95 degrees C, substrate mole ratio 275.57, and enzyme amount 39.81 mg/mL). Further, the adequacy of the predicted model was examined by additional independent experiments at the predicted maximum synthesis conditions. Results showed that the RSM was effective to optimize a combination of factors for lipase-catalyzed synthesis of ginsenoside Rb1 with vinyl decanoate.
authors.affiliation: Department of Food Science and Technology, Chungnam National University, Gung-Dong, Daejeon, Republic of Korea.
authors.forename: Jiang-Ning
authors.initials: JN
authors.lastname: Hu
authors.forename: Jeung-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Zhu
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Shin
authors.forename: Prakash
authors.initials: P
authors.lastname: Adhikari
authors.forename: Jae-Kyung
authors.initials: JK
authors.lastname: Kim
authors.forename: Ki-Teak
authors.initials: KT
authors.lastname: Lee
mesh_terms: D003651:Decanoates / Q000378:metabolism; D004800:Enzymes, Immobilized; D004951:Esterification; D005656:Fungal Proteins; D036145:Ginsenosides / Q000096:biosynthesis*; D008049:Lipase / Q000378:metabolism*; D015233:Models, Statistical; D000439:Pentanols; D010928:Placental Lactogen; D012997:Solvents; D053719:Tandem Mass Spectrometry; D014753:Vinyl Compounds / Q000378:metabolism
chemical_list: D003651:Decanoates; D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D036145:Ginsenosides; D000439:Pentanols; D012997:Solvents; D014753:Vinyl Compounds; C032765:tert-amyl alcohol; C442759:ginsenoside Rb1; D010928:Placental Lactogen; C093667:Novozyme 435; D008049:Lipase; C539564:vinyl decanoate