Physico-Chemical Properties of Purified Carboxylesterase from the Seeds of Tamarindus indica

The present work is focus on physical and chemical properties of purified Carboxylesterase using the Seeds of Tamarindus Indica.The esterases are extracted from the germinating tamarind seeds using 50 mM phosphate buffer, pH 7 and purified. The Km with α-naphthyl acetate, β-naphthyl acetate and α-naphthyl butyrate as the substrates is 28.6 μM, 22.2 μM and 26.7 μM respectively. The Vmax for the same substrates is 7.1 x 10-3 µmole/min, 7.41 x 10-3 µmole/min and 8.00 x 10-3 µmole/min respectively. The enzymes optimally active at pH 7.0 and are stable between pH 5.0 to 8.0. The optimum temperature of esterase activity is 40˚C. The molecular weight of 27.5 kD as determined by SDS-PAGE, both in the presence and absence of β-mercaptothanol and is in close agreement with the molecular weight determined by gel-filtration on Sephadex G-100 (26.9 kD).

Characterization and Immobilization of a Novel SGNH Family Esterase (LaSGNH1) from Lactobacillus acidophilus NCFM

The SGNH family esterases are highly effective biocatalysts due to their strong catalytic efficiencies, great stabilities, relatively small sizes, and ease of immobilization. Here, a novel SGNH family esterase (LaSGNH1) from Lactobacillus acidophilus NCFM, which has homologues in many Lactobacillus species, was identified, characterized, and immobilized. LaSGNH1 is highly active towards acetate- or butyrate-containing compounds, such as p-nitrophenyl acetate or 1-naphthyl acetate. Enzymatic properties of LaSGNH1, including thermal stability, optimum pH, chemical stability, and urea stability, were investigated. Interestingly, LaSGNH1 displayed a wide range of substrate specificity that included glyceryl tributyrate, tert-butyl acetate, and glucose pentaacetate. Furthermore, immobilization of LaSGNH1 by crosslinked enzyme aggregates (CLEAs) showed enhanced thermal stability and efficient recycling property. In summary, this work paves the way for molecular understandings and industrial applications of a novel SGNH family esterase (LaSGNH1) from Lactobacillus acidophilus.