Production, partial purification and characterization of a thermo-alkali stable xylanase from Bacillus sp. RPP-1

Bacillus sp. RPP-1, isolated from garden soil at University of Delhi, South Campus produced negligible cellulase, alkalothermostable xylanase in submerged fermentation (SmF). Among the various agro-byproducts tested, wheat bran induced the highest level of xylanase production (5740.0 IU L⁻¹). Peptone was found to be the best nitrogen source and supported maximum xylanase production (5840.0 IU L⁻¹). The partially purified xylanase was optimally active at 75°C, pH 7.0 with half-lives of xylanase at 70, 75 and 80°C were 120, 118 and 90 min, respectively. Xylanase was stable in a broad pH range 4.0–9.0 for more than 24 h at room temperature, retaining more than 65% of its activity. Surface-active detergents such as Tweens, Triton X100 and SDS stimulated the xylanase activity up to 41%, whereas metal ions, such as Mg²⁺ and Ca²⁺ stimulated the xylanase up to 58%, and Cu⁺², Pb⁺², Hg⁺² and Co⁺² and iodoacetamide and iodoacetic at 120, 118 and 90 min inhibited the enzyme activity.