In silico and in vitro studies of the reduction of unsaturated α,β bonds of trans-2-hexenedioic acid and 6-amino-trans-2-hexenoic acid – Important steps towards biobased production of adipic acid
Journal article, 2018

The biobased production of adipic acid, a precursor in the production of nylon, is of great interest in order to replace the current petrochemical production route. Glucose-rich lignocel-lulosic raw materials have high potential to replace the petrochemical raw material. A number of metabolic pathways have been proposed for the microbial conversion of glucose to adipic acid, but achieved yields and titers remain to be improved before industrial applications are feasible. One proposed pathway starts with lysine, an essential metabolite industrially produced from glucose by microorganisms. However, the drawback of this pathway is that several reactions are involved where there is no known efficient enzyme. By changing the order of the enzymatic reactions, we were able to identify an alternative pathway with one unknown enzyme less compared to the original pathway. One of the reactions lacking known enzymes is the reduction of the unsaturated α,β bond of 6-amino-trans-2-hexenoic acid and trans-2hexenedioic acid. To identify the necessary enzymes, we selected N-ethylmaleimide reductase from Escherichia coli and Old Yellow Enzyme 1 from Saccharomyces pastorianus. Despite successful in silico docking studies, where both target substrates could fit in the enzyme pockets, and hydrogen bonds with catalytic residues of both enzymes were predicted, no in vitro activity was observed. We hypothesize that the lack of activity is due to a difference in electron withdrawing potential between the naturally reduced aldehyde and the carboxylate groups of our target substrates. Suggestions for protein engineering to induce the reactions are discussed, as well as the advantages and disadvantages of the two metabolic pathways from lysine. We have highlighted bottlenecks associated with the lysine pathways, and proposed ways of addressing them.

Author

Emma Karlsson

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Jae Ho Shin

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Gunnar Westman

Chalmers, Chemistry and Chemical Engineering, Chemistry and Biochemistry

Leif A. Eriksson

University of Gothenburg

Lisbeth Olsson

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Valeria Mapelli

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

PLoS ONE

1932-6203 (ISSN)

Vol. 13 2 e0193503

Upgrading of renewable domestic raw materials to value-added bulk and fine chemicals for a biobased economy: technology development, systems integration and environmental impact assessment (BioBuF)

Västra Götalandsregionen, Regional development committee, 2013-11-01 -- 2018-10-31.

Formas, 2013-06-17 -- 2018-12-31.

Subject Categories

Biochemicals

Cell and Molecular Biology

Bio Materials

Other Industrial Biotechnology

DOI

10.1371/journal.pone.0193503

More information

Latest update

7/12/2018