Potential application of two thermostable lichenases from a newly isolated Bacillus licheniformis UEB CF: Purification and characterization

Two thermostable and alkali-stable beta-1,3-1,4 glucanases (EC 3.2.1.73) EG1 and EG2 from a newly isolated Bacillus licheniformis UEB CF were purified. The molecular weights of EG1 and EG2 enzymes determined by SDS-PAGE were approximately 30 kDa and 55 kDa, respectively. The N-terminal amino acid sequences of EG1 and EG2 beta-glucanases were determined to be GAAPIKKGTTKLN and DINGGGATLPQK, respectively. The optimum temperature, optimum pH, k(m) and V-max of EG1 were 70 degrees C, 5.0, 2.1 mg/ml and 21.25 mu mol/min/mg, respectively. These values for EG2 were 60 degrees C, 7.0, 1.82 mg/ml and 18.54 mu mol/min/mg, respectively. Both endoglucanases were highly active against barley beta-glucan and lichenan. However, they were inactive against CMC and laminarin. The purified beta-glucanases were found to be relatively stable toward non-ionic surfactants and oxidizing agents. In addition, both enzymes showed excellent stability and compatibility with a wide range of commercial solid detergents suggesting that they are a potential candidate in detergent industries formulation. (C) 2012 Elsevier Ltd. All rights reserved.