L-Iditol production from l-sorbose by a methanol yeast, Candida boidinii ( Kloeckera sp.) No. 2201

Abstract

Production of l-iditol (iditol) from l-sorbose (sorbose) with d-sorbitol dehydrogenase coupled with NADH regeneration under methanol oxidation was studied with the resting cell system of a methanol yeast, Candida boidinii (Kloeckera sp.) no. 2201. Maximum activities of iditol production and enzymes concerned with the production were found in cells grown on a medium containing methanol and d-xylose (xylose). The highest amount of iditol, 142–148 g/ l (94–98% conversion rate), was obtained from 150 g/ l of sorbose in the presence of 0.5 M methanol at pH 6.5. Intermittent control of the pH during the cell reaction gave a significantly higher amount of iditol than that obtained without such control. Freeze-thawing cells showed rather higher productivity than resting cells. The product was identified as iditol without contamination of its C-2 epimer, d-sorbitol, by high performance liquid chromatography.