A multi-step chromatographic strategy to purify three fungal endo-β-glucanases

Fungi and fungal enzymes have traditionally occupied a central role in biotechnology. Understanding the biochemical properties of the variety of enzymes produced by these eukaryotes has been an area of research interest for decades and again more recently due to global interest in greener bio-production technologies. Purification of an individual enzyme allows its unique biochemical and functional properties to be determined, can provide key information as to the role of individual biocatalysts within a complex enzyme system, and can inform both protein engineering and enzyme production strategies in the development of novel green technologies based on fungal biocatalysts. Many enzymes of current biotechnological interest are secreted by fungi into the extracellular culture medium. These crude enzyme mixtures are typically complex, multi-component, and generally also contain other non-enzymatic proteins and secondary metabolites. In this chapter, we describe a multi-step chromatographic strategy required to isolate three new endo-β-glucanases (denoted EG V, EG VI, and EG VII) with activity against cereal mixed-linkage β-glucans from the thermophilic fungus Talaromyces emersonii. This work also illustrates the challenges frequently involved in isolating individual extracellular fungal proteins in general.