Among thirteen thermophilic fungal strains, viz. Mabranchea pulchella
var. sulfurea, Sporotrichum thermophile, Thielavia terrestris, Humicol
a insolens and Acremonium alabamensis produced high levels of xylanoly
tic enzymes. The secretion of xylanolytic enzymes was higher in wheat
straw medium than in wheat straw hemicellulose. All fungi utilized xyl
ose as the carbon source. However, Mucor pusillus, Torula thermophila
and Sporotrichum thermophile consumed 90 - 93 % of xylose provided in
the medium while others utilized 51-83 %. The consumption of glucose b
y the fungi was high in comparison with that of xylose. Of all the tre
atments tried, xylose isomerase yield was highest when the mycelium of
Humicola insolens was homogenized with sand. The synthesis of xylose
isomerase was very high in wheat straw hemicellulose as compared with
that in xylose and glucose.