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In this work, the development of a chemoenzymatic process for the production of (1S,2R)-1-(methoxycarbonyl)cyclohex-4-ene-2-carboxylic acid by ECS-PLE06 (recombinant pig liver esterase) is presente...

A recombinant isoenzyme of pig liver esterase was used for the highly enantioselective desymmetrization of dimethyl cyclohex-4-ene-cis-1,2-dicarboxylate. The selected recombinant esterase showed a significant advantage in enantioselectivity over the commonly used esterase from the mammalian source. The process was scaled up to yield 265 g of product with a simplified pH control, and the target molecule was obtained with an enantiopurity of >99.5% ee.

Organic solvent nanofiltration (OSN) promises to be a versatile tool for mild and energy-saving downstream processing. In this case study, the use of modern solvent-resistant membranes to separate organocatalysts from reaction media was investigated. Commercially available membranes with molecular weight cut-offs (MWCOs) between 150 and 500 g mol–1 were used. They showed high rejections of up to 99% for native catalysts in THF. The enantioselective Henry reaction of ethyl pyruvate and nitromethane catalyzed by benzoyl cupreine was used to demonstrate the potential of this technique for preparative use.

The lipase-catalyzed polycondensation of sebacic aid and 1,4-butanediol can be performed in a biphasic reaction system composed of an aqueous reaction phase and an organic extraction phase. The shift of the equilibrium to higher product yields can be realized by the integrated product removal (IPR). In this biphasic reaction system the product yield, molecular weight and polydispersity is depending on the partitioning of the substrates and the product between the phases. By the biphasic approach substrate inhibition as well as molecular weight and polydispersity can be controlled by medium engineering. The polyester concentration can be increased up to 98% by optimising the reaction conditions. The molecular weight is limited in the biphasic system due to its removal while the polydispersity is independent of the reaction conditions but connected to the biphasic approach. Additional to the conversion the partition coefficients have been investigated either experimentally and via calculation by the quantum...

Theoretically, dynamic kinetic resolution gives stereochemically pure compounds in 100% yield. Practically, this target is seldom reached. In this work, we identified limiting factors for a given r...

The use of ionic liquids as alternative solvents for enzyme catalysis was investigated. β-Galactosidase from Bacillus circulans catalyses the synthesis of N-acetyllactosamine starting from lactose and N-acetylglucosamine in a transglycoslyation reaction. The addition of 25% v/v of 1,3-di-methyl-imidazol-methyl sulfate [MMIM] [MeSO4] as a water-miscible ionic liquid suppresses the secondary hydrolysis of the formed product, resulting in doubling the yield to almost 60%. The enzyme can be reused several times after ultrafiltration of the reaction mixture without loss of activity. Results of different amounts of ionic liquids in the reaction medium on the thermostability of the galactosidase as well as on oxidoreductases are presented as well.