Candida bombicola : production of novel alkyl glycosides based on glucose/2-dodecanol

Abstract

Candida bombicola produces glycolipids containing sophorose and a glycosidically/esterically bound ω- or (ω−1)-hydroxy C16(18) acid. Here we describe novel glycolipids from this source. Glucose and 2-dodecanol were used for the cultivation of the yeast, one part of the racemic secondary alcohol being connected directly with a glucose or a sophorose unit. A relatively high content of yeast extract, up to 4 g l−1, and subsequently higher biomass concentrations favoured the production of novel products. The provision of 150 g l−1 glucose and 15 g l−1 2-dodecanol resulted in maximum production of 22 g l−1 novel alkyl glycosides (more than 90% novel products). The molecular structures were analysed by gas chromatography, fast atom bombardment/mass spectrometry, 1H- and 13C-nuclear magnetic resonance and optical rotation studies. Sophorose and glucose were detected as carbohydrate moieties, (S)-(+)-2-dodecanol (88%) was found to be the major lipid moiety. The new glycolipids are suitable biosurfactants, reducing the surface tension of water from 72 mN m−1 to 32–38 mN m−1.