Lipase-Catalyzed Synthesis Of Maltose Myristate

Maltose myristate was one kind of nonionic-biosurfactants. At present, synthesis method of sugar ester in commercial process was almost chemical approach. In this paper, lipase-catalyzed synthesis of maltose myristate was researched. The research contents were as follows:the synthesis of maltose myristate, separation and detection conditions of the esters, product identification and results analysis.The raw materials of the reaction were maltose and myristic acid, using Novozym435as catalyst, molecular sieve was added to absorb water in the system to promote the esterifi cation.The influencing factor of the reaction were studied, included choosing final solvent, majorization of the reactor and the optimal conditions. When the dosage of maltose was30mmol/L, and with tertiary butyl alcohol as medium, the optimal conditions as follows: Novozym435of35g/L, the molar ratio of myristic acid to maltose was6:1, the temperature and time for the esterifi cation were70℃and72h. The maximum conversion of maltose was91.4%. The reacting time and molar ratio of reagent can influence the degree of esterification. When molar ratio of myristic acid to maltose was5:1-6:1, reacting for72h, the basises of the product were diesterase and trimester.The thin layer chromatography (TLC) used to qualitatively analyze maltose myristate was developed. The reaction mixture was applied to silica gel G plate, the mobile phase was chloroform/methanol/acetic acid/water (7.7:1.0:1.0:0.2, v/v), coloration by spraying10%phosphomolybdic acid alcohol solution and heated at105℃for10min. The Rf value of monoester and diesterase were0.20and0.50. High performance liquid chromatogram (HPLC) was used to analysis the product, using the column of Hypersil GOLD-C18(250mm×4.6mm) and the mobile phase of methanol:water85:15at a flow rate of1.0mL/min at40℃, RID-10A detector.The separation conditions of the sugar ester were researched. The myristic acid can be extracted with normal hexane followed by centrifugation (5000r/min,15min) for three times, but some ester was lost. The maltose was hard to be separated by extracting sugar ester with organic solvent, because the procuct can increase the solubility of maltose in organic solvent. So silica-gel column was used to isolate the ester, conditions as follows: the mobilephase as TLC,silica gel of200-300mesh, pillar of50x600mm,15mL/tube, detected by HPLC.The product was identified by Infra-Redspectrum(IR) and Liquid Chromatogram-Mass Spectrum(LC-MS), the results show that there were four types of outcomes with different degrees of esterification. So emulsifier of wide range HLB value can be produced in this reaction system.