Purification and characterization of a novel thermostable esterase from Thermus sp. NCCB 100425T / Thermus sp. NCCB 100425T'den yeni bir ısıya dayanıklı esterazın saflaştırılması ve karakterizasyonu

Objective: The purpose of the present study was to purify and characterize an esterase from a thermophilic bacterium Thermus sp. NCCB 100425T and to check its suitability for industrial applications. Methods: Thermus sp. NCCB 100425T esterase was purified by using ammonium sulphate precipitation and hydrophobic interaction chromatography and then characterized biochemically. Results: The purity of the enzyme was observed as a single band on native- and SDS- PAGE. In the presence of p-nitrophenyl acetate (pNPA) as a substrate, the optimum pH and temperature of the enzyme were found to be 7.5 and 60°C, respectively. Km and Vmax values are calculated as 18.32 mM and 96.15 U/mg protein, respectively, with pNPA. pH stability was investigated in the range of pH 4.0-9.0 at 4°C and 60°C. After 7 days incubation, activity of pure enzyme was retained 85-90% for all pH at 4°C and 59±5.2% for pH 8.0 at 60°C. It was determined that approximately 80% of enzyme activity was retained between 30-60°C after 7 days incubation. In the presence of 10% ethanol and DMSO, the enzyme activity was retained 96±2.7% and 78±2.5%, respectively. Additionally, it was detected that some metal ions affect the enzyme activity at different ratios. Conclusion: It is clear that Thermus sp. NCCB 100425T esterase might have advantages for industrial and/or clinical applications in terms of especially its high thermal- and pH-stability. [ABSTRACT FROM AUTHOR]