Different organic components on silica hybrid matrices modulate the lipase inhibition by the glycerol formed in continuous transesterification reactions Lucas S. Martin a,b , Annie Ceron a , Pedro C. Oliveira a , Gisella M. Zanin b , Heizir F. de Castro a, * a Engineering School of Lorena, University of São Paulo, Lorena, SP, 12602-810, Brazil b Chemical Engineering Department, State University of Maringá, Maringá, PR, 87020-900, Brazil A R T I C L E I N F O Article history: Received 25 October 2017 Received in revised form 14 January 2018 Accepted 20 January 2018 Available online xxx Keywords: Lipase Hybrid matrices Glycerol affinity Lipase immobilization Transesterification A B S T R A C T Silica hybrid materials, functionalized via incorporation of three organic components: b-cyclodextrin (bCD), carboxymethyl-cellulose (CMC) and hydroxyethyl-cellulose (HEC) were synthesized by the sol– gel technique and results were compared to a well-defined matrix (silica–polyvinyl alcohol–SiO 2 –PVA) with respect to immobilizing Burkholderia cepacia lipase. The main objective was set to select organic components that can replace the PVA to obtain a hybrid composite with greater hydrophobic character, without compromising the remarkable features of SiO 2 –PVA. All the three selected compounds allowed obtaining matrices that presented similar textural and morphological properties and gave high activity (1451–1661 U g 1 ) and thermal stability (t 1/2 > 70 h) upon immobilization. Regarding glycerol affinity, all matrices had lower ability than SiO 2 –PVA to adsorb glycerol, with the SiO 2 –bCD matrix showing the lowest affinity due to the cyclic structure of the bCD. Transesterification reactions of palm kernel oil with ethanol mediated by B. cepacia immobilized on SiO 2 –bCD performed in a packed bed reactor under continuous flow confirmed the efficiency of the SiO 2 –bCD matrix in increasing the operational stability of system, revealing a half-life (t 1/2 = 1040 h), 2.5 times greater than that achieved in the same system using lipase immobilized on SiO 2 –PVA (t 1/2 = 430 h). © 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. Introduction The use of immobilized enzymes has been shown to offer several advantages over the use of enzymes in their free forms [1,2]. Immobilized enzymes are more robust and more resistant to environmental changes [2]. More importantly, the heterogeneity of these immobilized systems allows an easy recovery of both the enzymes and products, and hence multiple reusing of enzymes, continuous operation of enzymatic processes, and greater variety of bioreactor designs [3,4]. Furthermore, immobilization often leads to enhance the thermal stability of enzymes, and it is essential to perform reactions in non-conventional media [5,6]. Immobilization of enzymes has been carried out using different techniques, including adsorption, covalent attachment, or entrap- ment [2,7] on several matrices [5,8,9]. The choice of the matrix usually depends on its desired features for a potential industrial application, such as its mechanical strength, chemical and physical stability, hydrophobic character, loading capacity, and cost [3,10,11]. It is well known that the properties of a supported enzyme are governed by the properties of both the enzyme and the carrier material [12]. The interaction between the two components provides an immobilized enzyme system with specific chemical, biochemical, mechanical, and kinetic properties [2,12,13]. The support (carrier) can be a synthetic organic polymer, a biopolymer, or an inorganic polymer [5,8,9]. An alternative approach uses a combination of inorganic and organic components to produce matrices with specific features for a particular application or to achieve distinct supports that are not found in conventional materials [14,15]. A convenient method to obtain organic–inorganic hybrid materials is the sol–gel technique [16– 18]. This method is employed to generate materials with a wide range of inner chemical surface. Hence, these materials are suitable to immobilize enzymes and allow the combination of the chemical and physical properties of the guest component with the excellent * Corresponding author. E-mail address: heizir@dequi.eel.usp.br (H.F. de Castro). https://doi.org/10.1016/j.jiec.2018.01.029 1226-086X/© 2018 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. Journal of Industrial and Engineering Chemistry xxx (2018) xxx–xxx G Model JIEC 3848 No. of Pages 9 Please cite this article in press as: L.S. Martin, et al., Different organic components on silica hybrid matrices modulate the lipase inhibition by the glycerol formed in continuous transesterification reactions, J. Ind. Eng. Chem. (2018), https://doi.org/10.1016/j.jiec.2018.01.029 Contents lists available at ScienceDirect Journal of Industrial and Engineering Chemistry journal homepa ge: www.elsev ier.com/locate/jie c