Production of ( S)-citronellic acid and ( R)-citronellol with an interface bioreactor

Abstract

Microbial transformation of racemic citronellol with Hansenula saturnus IFO 0809 was carried out on the interface between a hydrophilic carrier and a hydrophobic organic solvent (interface bioreactor). This system enabled the conversion of a high concentration of this toxic and hydrophobic compound. The strain accumulated ( S)-citronellic acid of 70–85% e.e. as an oxidation product, leaving behind ( R)-citronellol of 68–70% e.e. in the solvent layer. Using a large-scale, pad-packed interface bioreactor, ( S)-citronellic acid (82% e.e.) and ( R)-citronellol (77% e.e.) were accumulated at 18.0 and 17.8 g/ l respectively in the decane layer.