Green synthesis of isopropyl myristate in novel single phase medium Part I: Batch optimization studies Rajeshkumar N. Vadgama, Annamma A. Odaneth*, Arvind M. Lali DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathalal Parikh Marg, Matunga (E), Mumbai 400 019, India A R T I C L E I N F O Article history: Received 3 August 2015 Received in revised form 16 October 2015 Accepted 16 October 2015 Available online 24 October 2015 Keywords: Isopropyl myristate Myristic acid Isopropyl alcohol Novozym 435 Esterification A B S T R A C T 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. ã 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction The fatty acid esters have a broad range of applications in industries such as cosmetic industry, food industry, the pharma- ceutical industry, the coating industry, lubricants, biodiesel etc. [1,2]. The esters of fatty acids includes methyl esters, isopropyl esters, butyl esters, partial glycerides and wax esters (esters of fatty acids with long-chain fatty alcohols), and ester oils (esters of fatty acids with poly alcohols) [1–3]. The commonly used fatty acid ester, isopropyl myristate (IPM), is the main focus of present research. IPM, the isopropyl ester of myristic acid, is used in cosmetics as a substitute for natural oils because it has excellent spreading properties and is absorbed easily into the skin. In many topical and transdermal preparations, IPM is also used as a co-solvent with skin penetration enhancement properties of active ingredients [4]. Conventional methods for IPM synthesis involve the use of chemical catalyst at high temperatures. But this result in undesirable changes in a final product with respect to colour, odour, and stability, hence there is need for post refining steps which increases overall unit processes [5]. Therefore, nowadays the use of an enzyme catalyzed reaction is in focus to replace the conventional methods. Recently, many lipase based catalysis for esters have been reported wherein the esterification reaction were enhanced by reaction/enzyme engineering [6–9]. In accompanying papers the lipase-catalyzed esterification of myristic acid and isopropyl alcohol to produce isopropyl myristate ester was studied [10,11]. They have used organic solvents like heptanes, petroleum ether to carry out esterification reaction. However, use of such organic solvents creates two phase system, hence has downstream processing problems. Further theses conditions affect an enzyme activity adversely. Hence, there is need for medium engineering in order to develop the improved esterification reaction system. Additionally, lower rate of reaction and yield in enzymatic route needed to be addressed for an efficient isopropyl myristate synthesis reaction. In this paper, we have reported green synthesis of isopropyl myristate in a single phase medium. The novel approach for homogenization of two distinct substrates, i.e. myristic acid and isopropyl alcohol was established. Use of alcohol component in excess made the whole reaction system more realistic in terms of rate of synthesis and downstream processing. The various reaction parameters involved green synthesis of isopropyl myristate systematically studied. This paper promises a high performance synthesis of isopropyl myristate by enzymatic route using an immobilized lipase B from Candida antartica. * Corresponding author. Fax: +91 22 24145614. E-mail addresses: rajesh.vdgm@gmail.com (R.N. Vadgama), a.annamma@ictmumbai.edu.in, a.dbtceb@gmail.com (A.A. Odaneth), arvindmlali@gmail.com (A.M. Lali). http://dx.doi.org/10.1016/j.btre.2015.10.006 2215-017X/ã 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Biotechnology Reports 8 (2015) 133–137 Contents lists available at ScienceDirect Biotechnology Reports journal homepage: www.else vie r.com/locat e/btre