Characterization of a new thermalstable carboxylesterase from Aneurinibacillus sp. PDF24

Esterases (EC 3.1.1.1) represent a group of hydrolases that catalyze the formation and fission of ester links. They are very common in animals, plants, and microorganisms. Many of them show a wide substrate tolerance which led to the assumption that they have evolved to enable access to carbon sources or to be involved in catabolic pathways. What attracts the interest in these enzymes is the fact that they do not require cofactors, are usually rather stable, and are even active in organic solvents. The fact that thermophilic enzymes that thermophilic bacteria-growing at very high temperatures- posses are utilized in biotechnology and industry, attach a great significance to these bacteria.This study is about the purification and characterization of esterase obtained from the Aneurinibacillus sp. PDF24 strain, a thermophilic bacteria. The Aneurinibacillus sp. PDF24 strain was expressed and purified in degryse medium. The maximum activity of the purified esterase was analyzed at 55°C, pH 8.5. The values Km 0,120 mM and Vmax 3164,8 U/mg for p-nitrophenyl butyrate were calculated. Km was determined to have a better value compared to the other esterases in literature. The effect metal ions Mg2+, Li+, Ca2+, K+, Zn2+, and Co2+ was examined. The molecular weight of Aneurinibacillus sp. PDF24 esterase was determined about 40 kDa. Considering the obtained data, the biochemical features of the enzyme, show that it can be an important industrial enzyme.