Green synthesis of isopropyl myristate in novel single phase medium Part I: Batch optimization studies

•Green synthesis of isopropyl ester in homogenous phase reaction system.•Candida antarctica Lipase B (CAL-B) enzyme has efficiently catalyzed the esterification of myristic acid and isopropyl alcohol.•CAL-B activity depends on the polarity of an organic solvent.•Good operation stability of the enzyme was found in the single phase reaction system.•High purity of isopropyl myristate was obtained by the cold centrifugation technique.

Isopropyl myristate finds many applications in food, cosmetic and pharmaceutical industries as an emollient, thickening agent, or lubricant. Using a homogeneous reaction phase, non-specific lipase derived from Candida antartica, marketed as Novozym 435, was determined to be most suitable for the enzymatic synthesis of isopropyl myristate. The high molar ratio of alcohol to acid creates novel single phase medium which overcomes mass transfer effects and facilitates downstream processing. The effect of various reaction parameters was optimized to obtain a high yield of isopropyl myristate. Effect of temperature, agitation speed, organic solvent, biocatalyst loading and batch operational stability of the enzyme was systematically studied. The conversion of 87.65% was obtained when the molar ratio of isopropyl alcohol to myristic acid (15:1) was used with 4% (w/w) catalyst loading and agitation speed of 150 rpm at 60 °C. The enzyme has also shown good batch operational stability under optimized conditions.

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