Yeast platform for the production of 5-hydroxymethylfurfural-derivatives: Saccharomyces cerevisiae as a whole cell biocatalyst

Abstract

The utilization of lignocellulosic biomass for the production of biofuels has appeared as a possible solution to alleviate the envisioned depletion of fossil resources. Nevertheless, the attainment of economically viable lignocellulosic-based biorefineries requires the combined production of low value biofuels with high value compounds. 5-hydroxymethylfurfural (HMF) and its derivative 2,5Furandicarboxylic acid (FDCA) have been previously identified as top promising chemicals to be obtained from biomass. Therefore, this work explored the potential of (1) wine residues as renewable sources of hexoses for the production of HMF and (2) Saccharomyces cerevisiae-the preferred microorganism for bioethanol production- as a whole cell biocatalyst for the conversion of HMF into high value derivatives. For that, grape must and pomace were submitted to aqueous microwave treatment at different temperatures and durations for extraction of sugars and their dehydration into HMF. Moreover, different industrial S. cerevisiae strains were compared in terms of HMF conversion, showing different potentials for its oxidation or reduction: with 2,5Hydroxymethylfuran2carboxylic acid (HMFCA) production being favored under more aerobic conditions, while oxygen limitation favored 2,5- Bis(hydroxymethyl)furan (BHMF) accumulation. S. cerevisiae strains were then able to produce these compounds using an HMF-rich medium derived from wine residues. Also, genetic modifications of the yeast resulted in an increase in the accumulation of the further oxidized derivatives FDCA and 5formyl2furancarboxylic acid (FFCA). Taken together, these results prove S. cerevisiae to be a promising whole cell biocatalyst, allowing the envisioning of integrated biorefineries with combined production of biofuels and high value compounds.