Investigating pervaporation for in-situ acetone removal as process intensification tool in ω-transaminase catalyzed chiral amine synthesis Yamini Satyawali 1 , David Fernandes del Pozo 2 , Pieter Vandezande 1 , Ingmar Nopens 2 , Winnie Dejonghe 1 1 Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400, Mol, Belgium. Yamini.satyawali@vito.be Fax: +32 14 321186; Tel: +32 14 335741 2 BIOMATH, Department of Data Analysis and Mathematical Modelling, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium Abstract Hydrophobic pervaporation, allowing for the separation of an organic component from an aqueous stream, was investigated for in-situ acetone removal from a transamination reaction. A PDMS (PolyDiMethylSiloxane) membrane was applied in a coupled enzymatic process at 5 L scale. Among the four components, there was no loss of donor and product amines through pervaporation which was highly desirable. However, in addition to removal of acetone, there was also an unwanted loss of acetophenone (substrate ketone) due to pervaporation. The coupled enzyme-pervaporation process resulted in 13% more product formation compared to the control process (where no pervaporation was applied) after 9 h. Results from a qualitative simulation study (based on partial vapour pressures and a Vapour-Liquid equilibrium of the feed solution) indicated that pervaporation might have an advantage over direct distillation strategy for selective removal of acetone from the reaction medium. 1. Introduction Chiral, non-racemic pharmaceuticals are gradually increasing in the market and their production, using enantioselective technologies is highly important, to avoid the losses sustained from making racemic mixtures [1]. Chiral amines form the stereogenic core of many pharmaceuticals thus becoming one of the most essential structural components in this field [2]. Introduction of amine groups by synthetic methods is a highly tedious process, requires undesirable solvents or scarce metals as catalysts. Thus, the development of broadly applicable, efficient, and economic catalytic methods for the sustainable production of chiral amines is a key research priority of the pharmaceutical industry [1]. A ‘‘green alternative’’ to the conventional metal catalyzed reductive aminations would be the use of biocatalysts since it affords high enantio- and regioselectivity and provides a more sustainable and environmental friendly alternative compared to chemical processes [3, 4]. Using biocatalytic transamination based on ω-transaminases to transfer an amine functionality from a cheap donor molecule to a pro-chiral substrate has gained high interest from the industry due to the possibility of achieving high enantioselectivities under mild reaction conditions [5]. There are a few examples of process developments where high product titers, yields and, productivities are achieved. In 2010, Merck and Codexis received the Greener Reaction Conditions Award for greener manufacturing of Sitagliptin (the active ingredient in Januvia™, a treatment for type 2 diabetes), enabled by an evolved transaminase. Despite a few industrial examples, the widespread application of ω-transaminases for chiral amine synthesis has been hampered by fundamental challenges, including unfavorable equilibrium positions and product inhibition [6]. The thermodynamic equilibrium of transamination is most often shifted towards the substrates because the substrate ketone is usually much more stable than the corresponding amine, due to electron resonance effects [7]. The thermodynamic equilibrium of the reaction, product inhibition, Biocatalysts and Bioreactor Design Biotechnology Progress DOI 10.1002/btpr.2731 This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/btpr.2731 © 2018 American Institute of Chemical Engineers Biotechnol Prog Received: Mar 16, 2018; Revised: Jul 10, 2018; Accepted: Oct 09, 2018 This article is protected by copyright. All rights reserved. Accepted Article