Biotransformation of naphthalene and diaryl ethers by green microalgae

The role of green microalgae in thebiotransformation of naphthalene (a polycyclicaromatic hydrocarbon) and diaryl ethers wasinvestigated using axenic cultures ofChlorella vulgaris and two environmentalisolates, Scenedesmus SI1 andAnkistrodesmus SI2.Biotransformation experiments with dense cell culturesshowed that these three greenalgae transformed toxic xenobiotics to more polar metabolites.Chlorella vulgarismetabolized naphthalene to 1-naphthol (0.36–0.65%). Ankistrodesmus SI2 biotransformed dibenzofuran tosix metabolites (total over7%), three of which (possibly four) were identified as monohydroxylated dibenzofurans, the remaining two may be dihydroxylated derivatives. Scenedesmus SI1 biotransformeddibenzo-p-dioxin to three metabolites, one ofwhich was tentatively identified as2-hydroxydibenzo-p-dioxin (approximately 3.8%),the remainder may be dihydroxylated derivatives.This is the first time that the biotransformation of diaryl ethers by green microalgae has been investigated.