Application of RHA1 glycolate oxidase as an efficient accessory enzyme for lignin conversion by bacterial Dyp peroxidase enzymes.

Lignin oxidation by bacterial dye-decolorizing peroxidase enzymes requires hydrogen peroxide as a co-substrate, an unstable and corrosive oxidant. We have identified a glycolate oxidase enzyme from RHA1 that can couple effectively at pH 6.5 with DyP peroxidase enzymes from sp.

Elucidation of microbial lignin degradation pathways using synthetic isotope-labelled lignin.

Pathways by which the biopolymer lignin is broken down by soil microbes could be used to engineer new biocatalytic routes from lignin to renewable chemicals, but are currently not fully understood. In order to probe these pathways, we have prepared synthetic lignins containing C at the sidechain β-carbon. Feeding of [β-C]-labelled DHP lignin to RHA1 has led to the incorporation of C label into metabolites oxalic acid, 4-hydroxyphenylacetic acid, and 4-hydroxy-3-methoxyphenylacetic acid, confirming that they are derived from lignin breakdown.