Vol.:(0123456789) 1 3 Bioprocess and Biosystems Engineering https://doi.org/10.1007/s00449-019-02257-9 RESEARCH PAPER Synthesis of 2‑ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on a magnetic polymer support in continuous fow Mateus V. C. da Silva 1  · Amanda B. Souza 1  · Heizir F. de Castro 1  · Leandro G. Aguiar 1  · Pedro C. de Oliveira 1  · Larissa de Freitas 1 Received: 23 August 2019 / Accepted: 15 November 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract This study investigated the synthesis of 2-ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on magnetic poly(styrene-co-divinylbenzene) particles in a continuous packed-bed bioreactor. Runs were carried out in a solvent-free system at 50 °C. The performance of the reactor was evaluated for substrates composed by oleic acid and 2-ethylhexanol at fve molar ratios (1:4–4:1), determining its operation limits in terms of substrate fow rate. The system performance was quantifed for three diferent fow rates corresponding to space-time between 3 and 12 h. For each condition, the infuence of the space-time in the ester formation, esterifcation yield and productivity was determined. The molar ratio of acid-to- alcohol interfered, in a remarkable way, in the formation of 2-ethylhexyl oleate and the best performance was attained for substrate at equimolar ratio running at 12 h space-time. Under this condition, average 2-ethylhexyl oleate concentration was 471.65 ± 2.98 g L −1 which corresponded to ester productivity of 23.16 ± 0.49 mmol g −1  L −1  h −1 . This strategy also gave high biocatalyst operational stability, revealing a half-life time of 2063 h. A model based on the ping-pong Bi–Bi mechanism was developed to describe the kinetics of the esterifcation reaction and validated using experimental data. The goodness of ft of the model was satisfactory (R 2 = 0.9310–0.9952). Keywords Kinetic modeling · Esterifcation · Immobilized lipase · Magnetic polymer · Packed-bed reactor Introduction Emollient esters are widely used as skin softening and moisturizing agents in creams, lotions, sunscreen products, makeup, and antiperspirants. These components are biode- gradable, non-toxic, and have good solubility in oils and fats [1]. 2-Ethylhexyl oleate is an example of a commercially important ester with applications in the cosmetics, pharma- ceutical, food, and chemical industries [2, 3]. Currently, the vast majority of emollient esters used in cosmetics are derived from petroleum. However, envi- ronmentally conscious consumers have created a growing demand for high-quality, high-purity ingredients obtained from renewable sources, preferably through clean and sus- tainable technologies and in accordance with local and inter- national regulations [4, 5]. These changes necessitate the development of novel methods to obtain emollient esters. Lipases efectively catalyze hydrolysis, esterifcation, interesterifcation, and transesterifcation reactions. Their chemo-, regio-, and stereospecifcity make them promising catalysts for the synthesis of products of commercial inter- est. Furthermore, lipases can synthesize high-purity products under mild pressure and temperature conditions, facilitating purifcation steps and reducing the amount of energy spent in the process. However, in their free form, lipases have some disadvantages; they are difcult to recover, insoluble in some media, and unstable in organic solvents in certain pH and temperature ranges [6]. Enzyme immobilization has been applied to overcome these difculties. This technique improves the stability of enzymes to heat and extreme pH conditions and allows their recovery, thereby reducing the cost of enzymatic processes [7]. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00449-019-02257-9) contains supplementary material, which is available to authorized users. * Larissa de Freitas larissafreitas@usp.br 1 Department of Chemical Engineering, Engineering School of Lorena, University of São Paulo, Lorena, SP 12602-810, Brazil