Fungal Glucuronoyl and Feruloyl Esterases for Wood Processing and Phenolic Acid Ester/Sugar Ester Synthesis

Feruloyl esterases (FAEs, E.C. 3.1.1.73, CAZy family CE1) and glucuronoyl esterases(GEs, E.C. 3.1.1.-, CAZy family CE15) are involved in the degradation of plantbiomass by hydrolysing ester linkages in plant cell walls, and thus have potential use inbiofuel production from lignocellulosic materials and in biorefinery applications withthe aim of developing new wood-based compounds [1, 2]. GEs and FAEs are present inthe genomes of a wide range of fungi and bacteria.Under conditions of low water content, these enzymes can also carry out(trans)esterification reactions, making them promising biocatalysts for the modificationof compounds with applications in the food, cosmetic and pharmaceutical industry.Compared to the chemical process, enzymatic synthesis can be carried out under lowerprocess temperatures (50-60\ub0C) and results in fewer side products, thus reducing theenvironmental impact.We characterised new FAE and GE enzymes from mesophilic, thermophilic and coldtolerantfilamentous fungi produced in Pichia pastoris. The enzymes were characterisedfor both their hydrolytic abilities on various model substrates (methyl ferulate, pNPferulate)- for potential applications in deconstruction of lignocellulosic materials andextraction of valuable compounds - as well as for their biosynthetic capacities. Wetested and optimised the FAEs’ transesterification capabilities on ferulate esters in a 1-butanol-buffer system, with the aim of using the most promising candidates for theproduction of antioxidant compounds with improved hydrophobic or hydrophilicproperties, such as prenyl ferulate, prenyl caffeate, glyceryl ferulate and 5-O-(transferuloyl)-arabinofuranose