Enhanced biocatalytic degradation of lignin using combinations of lignin-degrading enzymes and accessory enzymes

Abstract

Methods for screening combinations of lignin-degrading enzymes and accessory enzymes for product release from polymeric lignin have been developed, using two colorimetric assays that can be applied in microtiter plate format. A set of 3 bacterial DyP-type peroxidase enzymes from Pseudomonas fluorescens, Comamonas testosteroni and Agrobacterium sp., two bacterial multi-copper oxidase enzymes CueO from Ochrobactrum sp. and CopA from Pseudomonas putida, and Sphingobacterium sp. T2 manganese superoxide dismutase have been tested in combination with one LigE β-etherase enzyme from Agrobacterium sp., two dihydrolipoamide dehydrogenase enzymes from Sphingobacterium sp. T2, Burkholderia cenocepacia peroxiredoxin, and Desulfitobacterium hafniense arylsulfotransferase. Combinations of Agrobacterium LigE with DyP-type peroxidases gave 4–10 enhancement in low molecular weight product release from technical lignins, and enhancements in product release were observed for all lignins tested, using different accessory enzymes. Analysis of products formed by reverse phase HPLC verified increases in concentrations of specific low molecular weight products.