title: Stimulation of alkalothermophilic Aspergillus terreus xylanase by low-intensity laser radiation.
abstract: In this study, Aspergillus terreus was irradiated by a 7.3 mW He-Ne laser in the presence of crystal violet, toluidine blue O and hematoporphyrin as photosensitizers. Xylanases recovered from non-irradiated and irradiated fungi were purified and characterized. The maximum production of xylanase (42.2 U/ml) was obtained after 5 min of laser irradiation in the absence of the photosensitizer. The irradiation of the sensitized fungus diminished the production of xylanase. On purification using G-100, the specific activity of xylanase recovered from the irradiated fungus was 292 U/mg protein representing a 37-fold purification over the crude extract compared with 95.6 U/mg protein representing the 12.8-fold for the enzyme recovered from the non-irradiated fungus. The enzyme recovered from the irradiated fungus had lower molecular weight as compared with that recovered from the non-irradiated one. Characterization of the purified enzymes revealed that the enzyme recovered from the irradiated fungus was more thermostable and had a wider range of optimum reaction temperature (60-70 degrees C) and pH (4.0-12.0), compared to the non-irradiated one.
authors.affiliation: Department of Botany, Faculty of Science, Cairo University, Giza 12613, Egypt. ngeweely@yahoo.com
authors.forename: Neveen S
authors.initials: NS
authors.lastname: Geweely
authors.forename: Salama A
authors.initials: SA
authors.lastname: Ouf
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Eldesoky
authors.forename: Amera A
authors.initials: AA
authors.lastname: Eladly
mesh_terms: D001230:Aspergillus / Q000201:enzymology / Q000528:radiation effects*; D028022:Low-Level Light Therapy; D008970:Molecular Weight; D014990:Xylans / Q000737:chemistry / Q000378:metabolism; D014995:Xylosidases / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D014990:Xylans; D014995:Xylosidases