title: Thermostable xylanases produced at 37 degrees C and 45 degrees C by a thermotolerant Aspergillus strain.
abstract: Differences between xylanases produced by Aspergillus FP-470 growing under normal (37 degrees C) and temperature stress conditions (45 degrees C) were evaluated. Fungal growth at 45 degrees C was seriously affected. However, the xylanase specific activity was 2.5 times higher than that produced at 37 degrees C. Optimum pH and temperature were 6.5, 80 degrees C and 4.3, 50 degrees C for the xylanases produced at 37 degrees C and 45 degrees C, respectively. Electrophoresis showed that a more complex xylanolytic system was produced at 37 degrees C. Stress induced by temperature produced a decrease in the number of extracellular xylanases released by fungi, but increased the production of some xylanases, possibly essential for growth under stress conditions.
authors.affiliation: Department of Food Science and Biotechnology, Faculty of Chemistry, National University of México, Mexico D.F., Mexico.
authors.forename: L P
authors.initials: LP
authors.lastname: Mendicuti Castro
authors.forename: B A
authors.initials: BA
authors.lastname: Trejo-Aguilar
authors.forename: G
authors.initials: G
authors.lastname: Aguilar Osorio
mesh_terms: D001230:Aspergillus / Q000201:enzymology* / Q000254:growth & development; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000096:biosynthesis*
chemical_list: D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase