Properties and application of a partially purified alkaline xylanase from an alkalophilic fungus Aspergillus nidulans KK-99.
An alkalophilic Aspergillus nidulans KK-99 produced an alkaline, thermostable xylanase (40 IU/ml) in a basal medium supplemented with wheat bran (2% w/v) and KNO3 (at 0.15% N) pH 10.0 and 37 degrees C. The partially purified xylanase was optimally active at pH 8.0 and 55 degrees C. The xylanase was stable in a broad pH range of 4.0-9.5 for 1 h at 55 degrees C, retaining more than 80% of its activity. The enzyme exhibited greater binding affinity for xylan from hardwood than from softwood. The xylanase activity was stimulated (+25%) by Na+ and Fe2+ and was strongly inhibited (maximum by 70%) by Tween-20, 40, 60, SDS, acetic anhydride, phenylmethane sulphonyl fluoride, Triton-X-100. The xylanase dose of 1.0 IU/g dry weight pulp gave optimum bleach boosting of Kraft pulp at pH 8.0 and temperature 55 degrees C for 3 h reaction time.
Taneja
Kavita
K
Department of Microbiology, University of Delhi, New Delhi, India.
Gupta
Saurabh
S
Kuhad
Ramesh Chander
RC
D000089:Acetic Anhydrides / Q000494:pharmacology; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000254:growth & development; D017606:Chlorine Compounds; D003470:Culture Media; D004789:Enzyme Activation; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007221:Industry; D007501:Iron / Q000494:pharmacology; D009566:Nitrates / Q000378:metabolism; D010209:Paper; D038761:Photobleaching; D011136:Polysorbates / Q000494:pharmacology; D017680:Potassium Compounds / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D012964:Sodium / Q000494:pharmacology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013302:Streptomyces / Q000201:enzymology; D013379:Substrate Specificity; D013501:Surface-Active Agents / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014105:Tosyl Compounds / Q000494:pharmacology; D014908:Triticum / Q000737:chemistry / Q000378:metabolism; D043325:Xylan Endo-1,3-beta-Xylosidase; D014990:Xylans / Q000737:chemistry / Q000378:metabolism; D014995:Xylosidases / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*
D000089:Acetic Anhydrides; D017606:Chlorine Compounds; D003470:Culture Media; D009566:Nitrates; D011136:Polysorbates; D017680:Potassium Compounds; D011480:Protease Inhibitors; D013501:Surface-Active Agents; D014105:Tosyl Compounds; D014990:Xylans; C031800:acetic anhydride; D012967:Sodium Dodecyl Sulfate; C003614:4-toluenesulfonyl fluoride; D012964:Sodium; D007501:Iron; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; C023844:potassium nitrate