Bioreduction of carboxylic acids by Pyrococcus furiosus in batch cultures

The reduction of aromatic and aliphatic (di)carboxylic acids to their corre sponding aldehydes and alcohols by the hyperthermophilic organism Pyrococcu s furiosus was investigated. The reduction was performed with P. furiosus c ells growing in the presence of 1 mM acid with starch as a carbon and energ y source at 90 degrees C. The aromatic acids t-cinnamic and 3-phenylpropion ic acid were reduced to their corresponding alcohols with the highest yield s in the described batch cultures: 67 and 69%, respectively. The aliphatic acid reduced with the highest yield was hexanoic acid (yield: 38%). No alde hydes were detected-during the reduction of acids, indicating that the redu ction of aldehydes to alcohols is faster than the reduction of acids to ald ehydes. Some aldehydes were both reduced to the corresponding alcohol and o xidized to the corresponding acid. Besides reduction of the unsaturated t-c innamaldehyde to t-cinnamyl alcohol (63%), the double bond of t-cinnamaldeh yde was also reduced by P. furiosus. (C) 1999 Elsevier Science Inc. All rig hts reserved.