Biocatalysis for biomass conversion to bioplastics precursors

Lead Research Organisation: University of Liverpool
Department Name: Chemistry

Abstract

There is a current unmet need for sustainable methods for the bioconversion of biomass derived compounds into chemical precursors for enzyme catalysed polymerisation to make bioplastics. The Carnell group at the University of Liverpool have recently reported a combination of enzymes for the efficient conversion of cellulose-derived 5-hydroxymethylfurfural (HMF) to the bioplastics precursor 2,5-furandicarboxylic acid (FDCA), an aromatic dicarboxylic acid, in a one pot continuous process. To use aromatic dicarboxylic acids as polymer building-blocks requires energy intensive processes to extract and purify the diacids to allow them to then be reacted with non-biomass obtained alcohols for esterification. The project will focus on the development of an unexploited group of methyltransferase enzymes for the direct esterification of bio-derived dicarboxylic acids such as FDCA and pyridine diacids. The majority of methyltransferases employ the ubiquitous cofactor SAM as the methyl donor to methylate a range of structurally distinct substrates including carboxylic acids. Enzymes have evolved to work under mutually compatible conditions for multi-step synthesis and methyltransferases are able to perform under the same aqueous conditions in which the diacids are formed. By forming methyl esters using methyltransferases, they are suitable for transesterification by further enzymatic action to deliver a streamlined, highly atom efficient and sustainable route to important bioplastic precursors.

Publications

10 25 50
 
Description An enzyme has been identified that can perform the target reaction with a conversion of over 40% to the desired product, a bioplastic precursor. The enzyme has also been further characterised, including a predicted structure. A colorimetric assay has also been developed specific to this enzyme. This predicted structure and the assay will aid future mutagenesis of the enzyme to improve the overall activity and conversion to the target bioplastic precursor product.
Exploitation Route Further optimisation and mutagenesis of this enzyme is required to increase the conversion to the bioplastic precursor product. As the substrate scope was also explored, other potential target reactions could also be investigated.
Sectors Manufacturing

including Industrial Biotechology

Pharmaceuticals and Medical Biotechnology