Diversity of plant cell wall esterases in thermophilic and thermotolerant fungi.

Fourteen thermophilic and thermotolerant fungal strains isolated from composting soils produced plant cell wall-acting esterases in a medium containing corn cobs and oat spelt xylan. The concentrated and dialyzed protein extracts of these fungi were fractionated using isoelectric-focusing, gels sliced and eluted protein in each slice was assayed for esterase activity against p-nitrophenyl acetate. A total of 84 esterases detected on the basis of pI were found to show distinct preferential substrate specificities towards p-nitrophenyl acetate, p-nitrophenyl ferulate and p-nitrophenyl butyrate, and were putatively classified as acetyl esterases and esterases types I and II.

Two endoxylanases active and stable at alkaline pH from the newly isolated thermophilic fungus, Myceliophthora sp. IMI 387099.

Two extra-cellular endoxylanases (Xyl Ia and Ib) were purified to homogeneity from the newly isolated thermophilic fungus, Myceliophthora sp. IMI 387099. Xyl Ia and Ib, having a molecular mass of approximately 53 kDa and pI of 5.