Purification and Characterization of an extracellular endo-1,4-B-xylanase from Fusarium oxysporum f.sp. melonis.

ALCONADA TERESA; MARTINEZ MARÍA JESÚS

FEMS MICROBIOLOGY LETTERS

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 1994 vol. 118 p. 305 - 310

0378-1097

Fusarium oxysporum f. sp. melonis produces extracellular endo-l,4-/3-xylanase and /3-xylosidase when grown in shaken culture at 26°C in a mineral salts medium containing oat spelt xylan and glucose as carbon sources. Endo-l,4-/3-xylanase was purified 251 times from 5-day-old culture filtrates, by Sephacryl S-200, ion exchange and gel filtration HPLC. The purified sample yielded a single band in SDS polyacrylamide gels with a molecular mass of 80 kDa on electrophoretic mobility and 83 kDa by gel filtration behavior. High activity of the endo-l,4-/3-xylanase against xylan was observed between 5 and 8 pH, and between 40 and 60°C, the optimum pH and temperature being 5.0 and 50°C, respectively. Kinetic properties of the enzyme are similar to those of other fungal xylanases, showing high affinity towards oat spelt xylan with a K m of 1 mM expressed as xylose equivalent.