Pineapple Peel Extract as an Effective Substrate for Esterase Production from Bacillus subtilis E9
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Pineapple Peel Extract as an Effective Substrate for Esterase Production from Bacillus subtilis E9 Padinjarakavil Soumya1 · Jayachandran Kochupurackal1 Received: 19 February 2020 / Accepted: 3 June 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Esterase, belonging to hydrolase class of enzymes catalyzes the cleavage and formation of ester bonds. Esterase producing isolates E9 and E46, isolated from pineapple waste enriched soil were identified as Bacillus subtilis E9 and Bacillus sp. E46 respectively. Bacillus subtilis E9 with 10 U/mg esterase activity in basal media was further chosen for media optimization studies. Several factors including the effect of organic solvents and fruit peel extracts were studied by one factor at a time optimization method and statistical models. An enhanced enzyme production of 250.50 U/mg could be obtained under the optimal conditions of pH 6.5, incubation time 25 h and 1.8%v/v of acetone extract of pineapple peel. The four-stage purification improved the purity of the enzyme by 1.5-fold with 5.3% recovery and specific activity of 384 U/mg. The monomeric nature and the molecular weight (45 KDa) of the enzyme were determined by performing SDS PAGE and its activity was confirmed by zymogram analysis. The substrate specificity of the purified fraction exhibited a higher activity towards lower chain length esters, indicating the enzyme as esterase. The partially purified esterase showed an optimal temperature of 40 °C at an optimum pH of 7. Km and Vmax of the enzyme were 1.12 mM and 1.18 mM of released pNP · min−1 respectively.
Introduction Esterases (E C 3.1.1.x), a major group of hydrolytic enzymes are known to accelerate the synthesis or hydrolysis of several esters. They are widely distributed in animals and plants with major source of commercially available esterases from mammalian origin. However, some microbial esterases have been successfully used in industries owing to their stability, catalytic activity, ease of production and optimization than mammalian esterases [1]. Esterases are members of the α/β hydrolase family and possess a characteristic eight stranded αβ-fold comprising parallel β-sheets surrounded by α-helices. Most of the esterases share a similar active site residue involving a nucleophilic serine residue, an acidic residue and a histidine residue. These residues act cooperatively in the catalytic mechanism of ester hydrolysis.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00284-020-02073-5) contains supplementary material, which is available to authorized users. * Jayachandran Kochupurackal [email protected] 1
School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala 686560, India
Esterases generally being considerably hydrophobic, tend to aggregate in dimers, tetramers, or in more aggregated forms, displaying pseudo quaternary structures [2]. Apart from ester hydrolysis in aqueous medium, esterase can catalyse the esterification, interesterification, t
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