A universal and comparative heterologous expression system for fungal epoxide hydrolase encoding genes.
Michel Labuschagne (1), Catherine Madzak (2), Jacobus Albertyn (1)
(1) Biotechnology, University of the Free State, Nelson Mandela Ave., Bloemfontein, 9300, South Africa; (2) UMR Microbiologie et Génétique Moléculaire INRA - CNRS - INAPG, CBAI, 78850 Thiverval Grignon, France
Epoxide hydrolases (EHs) have the ability to catalyze the enantioselective hydrolysis of epoxides to diols via the addition of a water molecule to the epoxide moiety. Fungal EHs have been shown to be a valuable component in the quest to produce enantiopure epoxides and/or diols. Several attempts to perform heterologous expression of these genes in E. coli (even in the presence of different chaperones) resulted in formation of inclusion bodies, thereby limiting the use of this well established system. A universal recombinant EH production system to perform comparable EH studies is therefore needed and such a system should also allow increased activity and enantioselectivity when compared to the native organism. Here we report on the construction of an expression system that allows for direct comparison of transformants on flask and/or fermenter scale. This system has been validated with five fungal EH encoding genes and recombinant enzymes exhibited high activities and enantioselectivities towards various substrates.