Isolation, Purification, and Characterization of Haloalkaline Xylanase from a Marine Bacillus pumilus Strain, GESF-1

A haloalkalitolerant xylanase-producing Bacillus pumilus strain, GESF1 was isolated from an experimental salt farm of CSMCRI Birch wood xylan and xylose induced maximum xylanase production with considerable activity seen in wheat straw and no activity at all with caboxymethyl cellulose (CMC) A three step purification yielded 21 21-fold purification with a specific activity of 112 42 U/mg protein (unit expressed as mu mole of xylose released per min) Xylanase produced showed an optimum activity at pH 8 0, with approximately 50 and 30% relative activity at a pH 6 0 and 10 0, respectively The temperature optimum was 40 C and kinetic properties such as Km and V-max were 5 3 mg/mL and 042 mu mol/min/mL (6593 4 mu mol/min/mg protein) Xylanase activity (160 similar to 120%) was considerably enhanced in 2 5 to 7 5% NaCl with 87 and 73% retention of activity in 10 and 15% of NaCl Enzyme activity was enhanced by Ca2+, Mn2+, Mg2+, and Na+ but strongly inhibited by heavy metals such as Hg2+, Fe3+, Cu2+, Cd2+, and Zn2+ Organic reagents such as beta-Mercaptoethanol enhanced xylanase activity whereas EDTA strongly inhibited its activity Xylanase, purified from the Bacillus pumilus strain, GESF1 could have potential biotechnological applications