Screening and Identification of New Xyloglucan-Degrading Enzymes in Thermophilic Fungi

Lignocellulose biomass is the cheapest available source of carbohydrates for bioconversion technologies. Xyloglucan is the main part of structural polysaccharides in various plants.

Hydrolysis of xyloglucan is a necessary step of complete biomass degradation. Some glycosyl hydrolases degrade xyloglucan. The natural source of glycosyl hydrolases is microorganisms including bacteria and fungi.

Today the great number of xyloglycanase genes in bacteria was annotated in contrast to fungi. Fungal enzymes are investigated much less than bacterial ones, although both bacteria and fungi are symbiotic plants and can be producers of xyloglucanases. The expanding spectrum of enzymes xyloglucan hydrolyzing creates new opportunities for bioconversion.

All-Russian Collection of Industrial Microorganisms of  State Research Institute of Genetics and Selection of Industrial Microorganisms contains 607 strains of fungi. We selected thermophilic fungi from collection to find new producers of xyloglucanases. Screening and identification of the enzymes was carried out by a combination of methods of zymogram and MALDI-TOF. As a result, new xyloglucanases were identified and their genes were found for further cloning. For subsequent investigation the activity and specificity of enzymes, a new method of xyloglucan extraction from tamarind was developed and optimized by our group. The quality and purity of the obtained substrate did not differ from the commercial product.