Activity and Stability Studies Of Mucor miehei Lipase Immobilized in Novel Microemulsion-based Organogels

Abstract

Lipase from Mucor miehei was immobilized in bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) as well as lecithin water-in-oil (w/o) microemulsion-based organogels (MBGs) formulated with biopolymers such as agar and hydroxypropylmethyl cellulose (HPMC), respectively. These lipase-containing MBGs prove to be novel solid-phase catalysts for use in organic media. Using these organogels at 258C, various esterification reactions in non-polar solvents as well as in solvent free systems were possible. Apparent lipase activity was influenced to some extent by the nature and the concentration of biopolymers used. Lipase stability in such MBGs is much higher than that observed in w/o microemulsions. MBGs containing lipase functioned effectively in repeated batch syntheses of fatty esters. Kinetic studies have shown that ester synthesis catalyzed by immobilized lipase occurs via the Ping-Pong bi-bi mechanism in which only inhibition by excess of alcohol has been identified. Values of all kinetic parameters were determined.

Esterification reactions catalyzed by lipases immobilized in organogels: effect of temperature and substrate diffusion

“…Preparation of microemulsions and organogels AOT and lecithin microemulsions were prepared as described elsewhere (Delimitsou et al 2002). Lipasecontaining microemulsion-based organogels (MBGs) were prepared by adding appropriate amounts of lipase-containing microemulsion (0.2 mg lipase/ml of microemulsion) to a second solution of polymer in water (Delimitsou et al 2002).…”

“…Lipasecontaining microemulsion-based organogels (MBGs) were prepared by adding appropriate amounts of lipase-containing microemulsion (0.2 mg lipase/ml of microemulsion) to a second solution of polymer in water (Delimitsou et al 2002).…”

“…These gels provide the advantage of a ''double'' immobilization of the enzyme, primary into the microemulsion droplets and secondly on the ''network'' of the gelling agent. They are stable in several organic polar or non-polar solvents (Delimitsou et al 2002;Blattner et al 2006) and are successfully used for esterification of fatty acids as well as phenolic acids with aliphatic alcohols (Delimitsou et al 2002;Zoumpanioti et al 2006).…”

Biocatalysis using lipase encapsulated in microemulsion-based organogels in supercritical carbon dioxide

“…Apart from gelatin, biopolymers such as agar, kcarrageenan and cellulose have been reported to form MBGs as an enzyme immobilization matrix [22][23][24]. These gels overcome the restrictions to which the gelatin-based gels are subject with regard to biocatalytic applications, as they provide good mechanical and thermal stability and show high resistance to hydrophilic environments.…”

“…In this case, the lipase containing MBGs were put into vials where the solvent containing the substrates was added. The reactions took place at 35 • C and ambient pressure as described elsewhere [24].…”