The present invention is related to novel oxygenase involved in biosynthetic production of retro-carotenoids, in particular rhodoxanthin. The invention also features polynucleotides and the corresponding polypeptides comprising the full-length sequences of the novel gene/polypeptide and fragments thereof, in particular functional equivalents of said gene/polypeptide. The invention further relates to genetically engineered microorganisms and their use, in particular for biosynthesis of retro-carotenoids, such as e.g. rhodoxanthin.