Aromatic oxidations by Streptomyces griseus: Biotransformations of naphthalene to 4-hydroxy-1-tetralone

Streptomyces griseus NRRL 8090 catalyzed the biotransformation of naphthalene (1) to 4-hydroxy-1-tetralone (4) in good yield. The bioconversion pathway from 1 to 1-naphthol (2) and 1-tetralone (3) was surmised by feeding 2 and 3 as substrates and measuring 4 formation by gas chromatography. Tetralin and 1, 4-naphthoquinone were not biotransformed by S. griseus. 2-Methyl-1,4-naphthoquinone (5) was converted to 2-methyl-4-hydroxytetralone (6) while 2-methylnaphthalene was not a substrate for S. griseus. All products were isolated by solvent extraction, chromatographically purified and characterized by gas chromatography/mass spectrometry (GC/MS) and 1H- and 13C-NMR spectroscopy. Unlike previous work in fungi, 4 is the major naphthalene metabolite, and the pathway for S. griseus conversion of naphthalene is different.