Lignocellulose has been investigated in depth during the last decade because it offers a wide range of possibilities for its transformation into necessary and valuable consumer products, which are currently obtained from non-renewable fossil resources. Based on these perspectives, the concept of "biorefinery" was coined as an approach aimed at integrating green chemistry into processes aimed at obtaining chemical products, materials and renewable fuels, using technologies with low environmental impact. Therefore, it is necessary to design biotechnological processes that allow all these compounds to be produced from renewable resources, such as lignocellulosic waste and byproducts, in a circular economy context.
During last years, our group has studied and characterized different glycosyl hydrolases (GH) secreted by a strain of the fungus Talaromyces amestolkiae, isolated from cereal residues and identified and characterized in our laboratory for its high cellulolytic and xylanolytic potential. The b-glucosidases secretd by this strain are interesting for biomass saccharification, providing yields similar to those obtained with commercial enzymes, and the b-xylosidases have peculiar properties and have been used for the synthesis of glycosides of biotechnological interest. By rational design, this b-xylosidase has been converted into a thioglycolgase, an artificial variant that showed a drastic reduction in hydrolysis and formed the expected S-glycosides and glycosides from unexpected acceptors, extending its possible range of application.
In this project, we will expand the study of these enzymes. The elucidation of the structural features responsible for the peculiar catalytic activity of the currently characterized enzymes, and their modification by rational design to produce tailor-made enzymes will be carried out. In particular, we will investigate the conversion of some selected GH into two types of artificial variants, whose hydrolytic capacity is greatly reduced or abolished, thioglycoligases and glycosynthases, to catalyze the synthesis of glycoconjugates or even new oligo- and polysaccharides. We will continue searching for new catalysts in public databases of fungal genomes and we will also investigate other auxiliary proteins detected in T. amestolkiae genome, studying the action of selected enzymes for specific purposes and the enzymatic production of value-added products. The immobilization of the selected catalysts is also a priority for the competitive and sustainability of some reactions for waste valorization.