ISOLATION, PURIFICATION AND CHARACTERIZATION OF ALKALI AND THERMO STABLE XYLANASE FROM BACILLUS SP. KS09

Abstract

Nine bacterial strains were isolated using xylan rich media. The bacterial strain KS09 was selected on the basis of qualitative and quantitative test. It was identified as Bacillus sp. via physiological, morphological and biochemical characterization. The xylanase was purified to homogeneity from crude extract of Bacillus sp. KS09 using ammonium sulphate fractioning and CM-Sephadex C-50. The final purification fold was 10.20 with a recovery of 36.18%. The enzyme was optimally active at 50°C, pH 7.0 and stable over a broad pH range of 6.0-11.0. The residual activity at 6.0-11.0 pH was 100% even upto 3 h of incubation. The enzyme showed 75, 70 and 60% thermal stability at 50, 55 and 60°C, respectively after 1 h of incubation. The kinetic parameters (K_m 22.59 mM; V_max 76.93 IU/mL) were estimated using Lineweaver-Burk plot for purified xylanase. The xylanase activity was inhibited by all the metal ions applied. The characteristic studies revealed that xylanase including its cellulase free nature, broad pH stability and temperature stability are particularly suited its industrial applications.