Effect of water activity and immobilization on fatty acid selectivity for esterification reactions mediated by lipases

Abstract

The effect of water activity (a(w)) and immobilization on fatty acid (FA) selectivity of Burkholderia (formerly Pseudomonas) cepacia, Rhizomucor miehei, Candida antarctica (type B), and Candida rugosa lipases in esterification reactions was determined. Studies were based on measuring ester formation in multicompetitive reaction mixtures containing either the homologous series of even carbon number n-chain saturated FA (C4-C18) or a series of n-chain (un)saturated FA (C18:X, where X = 0-3 double bonds) as cosubstrates with 1,3-propanediol in ter-butyl methyl ether at a(w) of 0.19, 0.69, and 0.90. Activity and FA selectively patterns were similar for free and Celite-adsorbed lipases in response to changes in a(w'), although specific effects were observed for selectivity of B. cepacia and C. rugosa lipases toward C16 and C4/C6 FA, respectively. Also, selectivity toward unsaturated C18:X FA as a group was modulated by changes in a(w) for three of the four lipase studied. Resin-fixed lipases from R. miehei and C. antarctica exhibited profound differences in activity and FA selectively in response to changes in a(w'), relative to free and Celite-bound forms. These findings suggest that FA selectivity for lipid modification is influenced by a(w) and immobilization, but that each lipase has a characteristic response to these factors in a manner that cannot be predicted.

Effect of Solvents and Kinetic Parameters on Synthesis of Ethyl Propionate Catalysed by Poly (AAc-co-HPMA-cl-MBAm)-Matrix-Immobilized Lipase of Pseudomonas aeruginosa BTS-2.

“…Compared with conventional chemical synthesis from alcohols and carboxylic acids using mineral acids as a catalyst, the use of enzymes, such as lipases, as biocatalysts to produce these high value-added fatty acid esters in organic media offers significant advantages (Klibanov 1986;Dordick 1989;Malcata et al 1990;Bornscheuer 1995;Yahya et al 1998;Basri et al 2001). Various features of reaction selectivity of lipases are modulated by exogenous factors such as type of organic solvent, choice of co-substrates/reactants, water activity, pH, temperature and immobilization support (Jensen et al 1990;Bornscheuer & Yamane 1994;Klein et al 1997;Rhee & Kwon 1998;Lee & Parkin 2001). In the present study, a weakly hydrophilic poly (AAc-co-HPMA-cl-MBAm) hydrogel efficiently immobilized an alkaline lipase from a thermophilic strain of P. aeruginosa, BTS-2.…”

Enzymatic Synthesis of Butyl Ferulate by Silica-Immobilized Lipase in a Non-Aqueous Medium

“…Various features of reaction selectivity of lipases are modulated by exogenous factors such as type of organic solvent, choice of co-substrates/reactants, water activity, pH, temperature and nature of support matrix [22][23][24][25]. The lipase after immobilization onto silica was exposed to glutaraldehyde that acts as a crosslinking agent and is effective against dilution induced dissociation of enzyme [26].…”

“…The effect of reaction temperature (25,35,45,55, and 65˚C) on the synthesis of butyl ferulate was studied in Teflon-capped glass-vials (5 ml). The reaction mixture containing butanol, ferulic acid (100 mM:50 mM) in DMSO and silica-immobilized lipase (30 mg/reaction volume of 2 ml) were incubated at each of the selected temperatures for 6 h under shaking.…”

Properties of poly(AAc‐co‐HPMA‐cl‐EGDMA) hydrogel‐bound lipase ofPseudomonas aeruginosaMTCC‐4713 and its use in synthesis of methyl acrylate

“…23 Various features of reaction selectivity of lipases are modulated by exogenous factors such as choice of cosubstrates/reactants, water activity, pH, salt ions, temperature, and immobilization. [34][35][36][37][38] The hydrogelbound lipase of P. aeruginosa MTCC-4713 was optimally active at pH 8.0 and temperature 458C. Recently, lipase from a mutant strain of Corynebacterium sp.…”