TY - JOUR A2 - Singh, O. V. A2 - Kues, W. A. AU - Kamble, Rajashri D. AU - Jadhav, Anandrao R. PY - 2013 DA - 2012/07/17 TI - Properties and Application of a Partially Purified Thermoalkali Stable Xylanase from Cellulosimicrobium sp. MTCC 10645 in Kraft Pulp Bleaching SP - 872325 VL - 2013 AB - The most promising application of xylanases (E.C. 3.2.1.8) is in the prebleaching of kraft pulp. The present paper reports bleaching effects of a thermoalkali stable xylanase from Cellulosimicrobium sp. MTCC 10645. The bacterium produced thermo-alkali stable xylanase in a basal medium supplemented with wheat bran (1% w/v), which was optimally active at pH 7.0 and 50°C. The xylanase was stable at temperature 50°C for 1 h and retained up to 86% of the activity. The xylanase was stable in a broad pH range of 6.0–11.0 for 1 h at 50°C. Metal ions Ca+2, Hg+2, and Pb+2 were inhibitory for xylanase retaining 72.3%, 35.07% and 36.7% relative activity at 10 mM concentration, whereas Fe+2, Cu+2, Mn+2, Na+2, Co+2, and Zn+2 were inducers at concentrations of 5 mM and 10 mM. The enzyme exhibited greater binding affinity exclusively for xylans but not for avicel, CMC, cellobiose, starch, or p-nitrophenyl xylopyranoside. Parachloromercuric benzoate and iodoacetamide were found stimulatory, while potassium permanganate, cysteine, and cystine markedly reduced the activity. The xylanase dose of 2.0 U/g dry weight pulp of 10% consistency gave optimum bleach boosting of kraft pulp at pH 8.0 and temperature 50°C for 5 h reaction time. SN - null UR - https://doi.org/10.5402/2013/872325 DO - 10.5402/2013/872325 JF - ISRN Biotechnology PB - Hindawi Publishing Corporation KW - ER -