Abstract
Pigment mutant C-2A′ of the unicellular green alga Scenedesmus obliquus develops only traces of chlorophyll and has no detectable amount of δ-aminolevulinic acid (ALA) when grown in the dark. In light it develops ALA and in the presence of levulinic acid (LA), a competitive inhibitor of ALA dehydratase, it accumulates 0.18 mmoles of ALA per 10 microliters of packed cell volume per 12 hours. This amount could be increased up to 15 times by feeding precursors and cofactors.