Tomoko Matsuda

Reduction of methyl ketones by dried cells of Geotrichum candidum (APG4) afforded (S)-alcohols in excellent enantiomeric excess (ee), whereas the reduction of trifluoromethyl ketones gave the corresponding alcohols of the opposite configuration also in excellent ee. The replacement of the methyl moiety with a trifluoromethyl group alters both the bulkiness and the electronic properties, the effect of which on the stereoselectivity was examined. No inversion in stereochemistry was observed in the

Enzymes have been used in non-aqueous media to make the reactions and the following process more efficient and greener. Here, recent progress in enzymatic reactions in supercritical carbon dioxide is reviewed. Hydrolysisesterification, oxidation-reduction and carboxylation are described, including highly enantioselective reactions. Keywords: lipases, hydrolysis, esterification, enantioselectivity

Alcohol dehydrogenase from Geotrichum candidum was found to be active in supercritical carbon dioxide at 10 MPa; high activities and excellent enantioselectivities were observed for the asymmetric reduction of aromatic and cyclic ketones.

Enzyme immobilization has been extensively employed in research and industry to improve enzyme stability and allow enzyme recycling. Broad ranges of chemicals and support materials have been utilized for enzyme immobilization. Recent breakthroughs in nanotechnology and materials science have influenced enzyme immobilization technology. Novel approaches for enzyme immobilization have enabled us to access more benefits, for example, excellent activity and stability, cost effectiveness, and the est

Recent developments of biocatalytic reduction of carbonyl groups are reviewed. Methods to find, prepare and modify the biocatalysts and to improve productivity and enantioselectivity of the reactions are explained. Then, practical applications for the asymmetric reduction of carbonyl compounds with various functionalities are given, including the synthesis of pharmaceutically important compounds. Keywords: glutathione S-transferase (GST), Redox Reaction, overexpression, Cofactor-Regenerating Enz

Pyrrole was converted to pyrrole-2-carboxylate in supercritical CO2 using cells of Bacillus megaterium PYR 2910, and the yield of the carboxylation reaction in supercritical CO2 was 12 times higher than that under atmospheric pressure.

A novel continuous-flow scCO(2) process for kinetic resolution of racemic alcohols can be performed with an immobilized lipase to lead to a quantitative mixture of the corresponding optically active acetates with up to 99% ee and unreacted alcohols with up to 99% ee, in which the productivity of the optically active compounds was improved by over 400 times compared to the corresponding batch reaction using scCO(2).

The immobilized resting-cell of Geotrichum candidum was used as a catalyst for the reduction of a ketone in a semi-continuous flow process using supercritical carbon dioxide for the first time; it was also applied for the asymmetric reduction of a ketone and resulted in excellent enantioselectivity (ee > 99%) and a higher space-time yield than that of the corresponding batch process.

Enzymes have been used in supercritical carbon dioxide (scCO2) rather than in the conventional media to make enzyme reactions greener. This review introduces some enzymatic asymmetric synthesis in scCO2 such as esterification by a lipase and reduction by an alcohol dehydrogenase. A carboxylation by a decarboxylase is also described.

Pyrrole was converted to pyrrole-2-carboxylate in supercritical CO2 using cells of Bacillus megaterium PYR 2910, and the yield of the carboxylation reaction in supercritical CO2 was 12 times higher than that under atmospheric pressure.