An alkali-halotolerant cellulase from Bacillus flexus isolated from green seaweed Ulva lactuca

Abstract An extracellular alkali-halotolerant cellulase from the strain Bacillus flexus NT isolated from Ulva lactuca was purified to homogeneity with a recovery of 25.03% and purity fold of 22.31. The molecular weight of the enzyme was about 97 kDa and the V max and K m was 370.17 U/ml/min and 6.18 mg/ml respectively. The optimum pH and temperature for enzyme activity was 10 and 45 °C respectively. The enzymatic hydrolysis of the CMC was confirmed with GPC and GC-MS analysis. The stabilized activity of the enzyme even at high pH of 9.0–12.0 and residual activity of about 70% at salt concentration (NaCl 15%) revealed for its alkali-halotolerance nature. The metal ions Cd 2+ and Li 1+ were found as inducers while Cr 2+ , Co 2+ , Zn 2+ and metal chelator EDTA have significantly inhibited the enzyme activity. Enzyme activity was insensitive to ethanol and isopropanol while partially inhibited by acetone, cyclohexane and benzene.