Research Information System
ICEST2011, Aydın, Turkey, vol.1, no.1, pp.58
Esterases represent adiverse group of hydrolases catalyzing the cleavage and formation of ester bonds[1,2]. Moreover, esterases catalyze esterification, inter-esterification and trans-esterification reaction in organic media[3]. Therefore, these enzymes the most widely used enzymes in organic synthesis and various industrial applications such as, detergent industry, paper industry and resolution of chiral drugs[1.4,5].
The esterase from a thermophilic bacterium, Geobacillus sp. DF20, was purified using Q-Sepharose ion exchange column and characterized. Native polyacrilamid gel electrophoresis stained by pnaphtyl acetate and Fast Blue B indicated the presence of two active esterase. Enzyme Show highest activity in presence of p-nitrophenyl butirate (p-NPB) as a substrate at pH 7.0 and 50 °C.
The Km and Vmax values of the enzyme were calculated as 0.120 mM and 54.6 U/mg protein, respectively. When the enzyme incubated in buffer solution pH 5.0 and 7.0 at 4 "C, the enzyme retained its original activity 70% and 50% respectively after 3 days. At 50 "C, the enzyme activity lost its activity at pH 5.0 after 2 days incubation and conserved 95% its activity after 3 days. The effects of metal ions and some chemicals on the activity were also investigated.These data support that the esterase from Geobacillus sp. DF20 has some advantages for industrial or biotechnological applications.