Xylan-degrading activity in yeasts: Growth on xylose,xylan and hemicelluloses

The ability to grow in liquid media withD-xylose, xylan from deciduous trees, and hemicelluloses from conifers was tested in 95 strains of 35 genera of yeasts and yeast-like organisms. Of 54 strains thriving on xylose, only 13 (generaAureobasidium, Cryptococcus andTrichosporon) utilized xylan and hemicelluloses as growth substrates. The árowth media of these strains were found to contain xylandegrading enzymes splitting the substrate to xylose and a mixture of xylose oligosaccharides. The ability of these yeasts to utilize the wood components (hitherto unknown in the genusCryptococeus) makes them potential producers of microbial proteins from industrial wood wastes containing xylose oligosaccharides, xylan, and hemicelluloses as the major saccharide components without previous saccharification.