Synthesis of ethyl acetate employing celite-immobilized lipase of Bacillus cereus MTCC 8372

Verma, M. L. and Azmi, W. and Kanwar, S. S. (2009) Synthesis of ethyl acetate employing celite-immobilized lipase of Bacillus cereus MTCC 8372. Acta Microbiologica et Immunologica Hungarica, 56 (3). pp. 229-242. ISSN 1217-8950

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A wide range of fatty acid esters can be synthesized by esterification and transesterification reactions catalyzed by lipases in non-aqueous systems. In the present study, immobilization of a purified alkaline extra-cellular lipase of Bacillus cereus MTCC 8372 by adsorption on diatomaceous earth (celite) for synthesis of ethyl acetate via transesterification route was investigated. B. cereus lipase was deposited on celite (77% protein binding efficiency) by direct binding from aqueous solution. Immobilized lipase was used to synthesis of ethyl acetate from vinyl acetate and ethanol in n -nonane. Various reaction conditions, such as biocatalyst concentration, substrates concentration, choices of solvents ( n -alkanes), incubation time, temperature, molecular sieves (3Å × 1.5 mm), and water activity(aw) , were optimized. The immobilized lipase (25 mg/ml) was used to perform transesterification in n -alkane(s) that resulted in approximately 73.7 mM of ethyl acetate at 55 °C in n -nonane under shaking (160 rpm) after 15 h, when vinyl acetate and ethanol were used in a equimolar ratio (100 mM each). Addition of molecular sieves (3Å × 1.5 mm) as well as effect of water activity of saturated salt solutions (KI, KCl and KNO3) to the transesterification efficiency has inhibitory effect. Batch operational stability tests indicated that immobilized lipase had retained 50% of its original catalytic activity after four consecutive batches of 15 h each.

Item Type: Article
Subjects: Q Science / természettudomány > QR Microbiology / mikrobiológia
Depositing User: xFruzsina xPataki
Date Deposited: 17 Sep 2017 14:50
Last Modified: 17 Sep 2017 14:50

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