Native and recombinant production of the glucuronoyl esterase from the litter decomposing fungus Stropharia coronilla

As the sustainable energy is becoming increasingly important, utilization of lignocellulosic biomass for biofuel production is the central part of this area. Fungal enzymes play an important role in lignocellulose degradation. Glucuronoyl esterase (GE) is a less studied fungal enzyme which degrades the ester linkage between lignin alcohol and hemicellulose side chain 4-O-methyl D-glucuronic acids. Genes encoding GE have been identified from various fungal species and they have been expressed in different production systems to be able to study their biochemical properties in detail. The gene encoding GE from the basidiomycete litter-decomposing fungus Stropharia coronilla was cloned and heterologous expressed in Pichia pastoris yeast. The expression and secretion of GE was induced by growing S. coronilla on lignocellulose supplemented cultivations. ScGE activity can be detected after the fifth day cultivation and it peaked on the 14th day. The heterologous expression of ScGE in P. pastoris showed that ScGE was produced as an enzymatically active protein. The commercial K-URONIC kit supplemented with a GE specific substrate benzyl-D-glucuronate was used to determine GE activity