Enzymatic Synthesis of Isopropyl Acetate by Immobilized   Bacillus cereus Lipase in Organic Medium

Abstract

Selective production of fragrance fatty acid ester from isopropanol and acetic acid has been achieved using silica-immobilized lipase of Bacillus cereus MTCC 8372. A purified thermoalkalophilic extracellular lipase was immobilized by adsorption onto the silica. The effects of various parameters like molar ratio of substrates (isopropanol and acetic acid; 25 to 100 mM), concentration of biocatalyst (25–125 mg/mL), reaction time, reaction temperature, organic solvents, molecular sieves, and initial water activity were studied for optimal ester synthesis. Under optimized conditions, 66.0 mM of isopropyl acetate was produced when isopropanol and acetic acid were used at 100 mM: 75 mM in 9 h at 55°C in n-heptane under continuous shaking (160 rpm) using bound lipase (25 mg). Addition of molecular sieves (3 Å × 1.5 mm) resulted in a marked increase in ester synthesis (73.0 mM). Ester synthesis was enhanced by water activity associated with pre-equilibrated saturated salt solution of LiCl. The immobilized lipase retained more than 50% of its activity after the 6th cycle of reuse.

Ultrasound technology and molecular sieves improve the thermodynamically controlled esterification of butyric acid mediated by immobilized lipase from Rhizomucor miehei

“…8 In this sense, the use of molecular sieves to control the excess of water in the reaction has been reported as a powerful tool to improve the enzyme performance, for example in the synthesis of isopropyl acetate in organic medium and in the synthesis of avor esters in ionic liquids. 9,10 Considering the use of immobilized lipases, the adsorption of water or substrates (carboxylic acid and alcohol) on the support is one of the most important reasons of biocatalyst inactivation. This might be solved by suitable washings to eliminate these compounds during successive batch operations.…”

Immobilisation of lipase on the surface of magnetic nanoparticles and non‐porous glass beads for regioselective acetylation of prednisolone

“…Therefore experiments have been carried out in order to prepare the acetylated derivatives of glucocorticoids [3]. Enzyme-mediated catalytic reactions to eliminate hazardous substances [4][5][6][7] and generate valuable products [8,9] have been widely researched in recent years. The remarkable regio-, enantio-and stereoselective functions of certain enzymes make them ideal for the mild and selective bioconversion of steroid functional groups [10,11].…”

Application of Lipase Purified from <i>Aspergillus fumigatus</i> in the Syntheses of Ethyl Acetate and Ethyl Lactate

“…3 . In a previous study, at a fixed concentration of acetic acid, an increase in the concentration of alcohol promoted the synthesis of ester 26 .…”

“…5 . The synthesis of ester is time dependent 26 . 98 Conversion of the reactants to ethyl acetate was achieved after 24 h of reaction using Staphylococcus pasteuri lipase immobilised on calcium alginate beads 25 .…”