The inducible microsomal fatty alcohol oxidase of Candida (Torulopsis) apicola

In the transition phase of Candida apicola IMET 43747 from logarithmic to stationary growth a pyridine-nucleotide-independent alcohol oxidase was induced coinciding with the beginning of sophorose lipid production. This enzyme was not repressed by glucose and was measurable in stationary cells grown on glucose or on a mixture of n-hexadecane and glucose. An NAD+-dependent aldehyde dehydrogenase behaved in the same way. Both enzymes were localized in the microsomal fraction. The alcohol oxidase accepted long-chain (fatty) aliphatic alcohols (C8 to at least C16) and diols starting from decanediol. Trace activities were found with ω-hydroxy fatty acids. Aromatic, secondary and tertiary alcohols were not oxidized. In the stationary growth phase the substrate specificity of the alcohol oxidase tends to be changed to more hydrophobic substrates. The physiological role of both enzymes, the alcohol oxidase and aldehyde dehydrogenase, is discussed including their possible involvement in the synthesis of sophorose lipid.