Reduction of Carboxylic Acids by Pyrococcus furiosus
Eyke VAN DEN BAN*, Hendra WILLEMEN, Hans WASSINK, Huub HAAKER, and Colja LAANE
Laboratory of Biochemistry, Department of Biomolecular Sciences, Agricultural University Wageningen, Dreijenlaan 3, 6703 HA Wageningen, The Netherlands
Naturally produced flavours are important for food industry. Many of these compounds are alcohols and aldehydes. Our group studies the formation of aldehydes and alcohols via microbial bioreduction of the corresponding acids. The hyperthermophilic archaeon Pyrococcus furiosus has been chosen as biocatalyst. P. furiosus rapidly grows on starch and has an optimal growth temperature of 90 - 100℃ (1).
These growth conditions allow a cheap, sterile production process in which volatile aldehydes and alcohols can be distilled in situ.
During its catabolism P. furiosus generates a strong reductant: reduced ferredoxin. This reductant is used directly or indirectly (via NADPH) in whole cell- catalysed reduction reactions (2). Reduction of acids to corresponding aldehydes is catalysed by a W-containing aldehyde oxidoreductase and the reduction of aldehydes to alcohols by alcohol dehydrogenases (3).
P. furiosus catalyses the reduction of aliphatic and aromatic acids to alcohols. Unsaturated compounds can also be reduced but this is dependent of the substrate. Data on the reduction capacity of P. friosus and yield will be presented.
1. Fiala, G. and Stetter, K.O. (1986) Arch. Microbiol., 145, 56-61.
2. Kengen, S.W.M., Stams, A.J.M., and De Vos, W.M. (1996) FEMS Microbiol. Rev., 18, 119- 137.
3. Ma, K., Loessner, H., Heider, J., Johnson, M.K., and Adams, M.W.W. (1995) J. Bacteriol., 177, 4748-4756.
