Esterases (EC 3.1.1.x), particularly microbial carboxyl esterases (EC 3.1.1.1) belong to the family of Serine esterases have been well known for catalysing short chain, water soluble esters. Ability to work against a broad range of substrates, selectivity towards particular stereoisomers and its stability in organic solvents draws interest towards its industrial applications. Crystallography studies have shown the presence of a consensus α/β hydrolase fold throughout the evolutionary lineages. The fold has a catalytic triad of Ser, His, Asp/ Glu and an oxyanion hole to stabilize the catalytic triad important for catalysis. L. plantarum Cest – 2923 is a carboxyl esterase isolated from psychrophilic habitat. Like other carboxyl esterases, it has α/β hydrolase fold with the catalytic Ser conserved in a motif of GFSAG and the catalytic triad is stabilized by Gly rich oxyanion hole.
Cold esterases have garnered keen attention of the research fraternity over the last decade owing to its low temperature operation, reduced susceptibility to microbial contamination and its potency in arresting the rapid evaporation of volatile compounds. However, lack of information on its biochemical properties and stability studies has resulted in its limited use. Therefore, this study is driven towards increasing the yield, further biochemical characterization and improving the stability of the enzyme from L. plantarum Cest – 2923 to enhance its potential as an efficient biocatalyst for industrial applications.