Continuous Enantioselective Transesterification in Organic Solvents. Use of Suspended Lipase Preparations in a Microfiltration Membrane Reactor

Abstract

A continuously stirred tank reactor equipped with a microfiltration membrane unit for effective retention of solid enzyme particles in organic solvent systems was constructed. A microfiltration membrane with pore size 0.1 μm based on a polypropylene matrice was used for enzyme retention and showed no loss of performance or denaturation by the organic solvent. The stereoselective transesterification reaction of (±)‐trans‐sobrerol with vinyl acetate as both acyl donor and solvent was chosen as a model system. Lipase PS from Pseudomonas sp. was used in its native form without further modification steps and remained active and highly stereoselective at 50 °C when applied to the reaction system for about 600 h of continuous operation. (‐‐)‐(1S,5R)‐sobrerolacetate and (+)‐(1R,5S)‐sobrerol could be obtained in the reactor outlet stream at approximately 48% conversion with enantiomeric excesses eeP ≈︁ 92% and eeS≈︁ 80%, respectively. Furthermore, theoretical kinetic studies showed that limitations in enantiomeric purity due to the characteristics of an ideal mixed tank may be sufficiently overcome by designing a simple two‐stage process.

Development of small-size tubular-flow continuous reactors for the analysis of operational stability of enzymes in low-water systems

“…The oxidation products of polyunsaturated fatty acids have often been implicated as enzyme poisons in lipasecatalyzed modifications of oils and fats, although there is only limited direct experimental evidence supporting this (Forssel et al, 1993;Indlekofer et al, 1995;Wisdom et al, 1987). Linseed oil is a well-known source of readily oxidized fatty acid residues.…”

Lipase-catalyzed acidolysis of fish liver oil with dihydroxyphenylacetic acid in organic solvent media

“…Most commonly known lipases are human pancreatic lipase, pig pancreatic lipase and pregastric lipase. Lipases have been employed in the production of pharmaceuticals, cosmetics, leather, detergents, foods, medical diagnostics and other organic synthetic materials (Indlekofer et al, 1995). This is largely due to their ready availability, high enzyme selectivity, low cost of production and enormous utility in organic synthesis.…”

Improvement of lipase stability in the presence of commercial triglycerides

“…An important bottleneck in lipase-based non-aqueous transformations is the poor operational stability of lipases in the presence of commercial triglycerides [6][7][8][9][10]. It is commonly believed that the enzyme is likely to be inactivated by impurities in raw substrates.…”