Anaerobic Mineralization of Stable-Isotope-Labeled 2-Methylnaphthalene

An active sulfate-reducing consortium that degrades 2-methylnaphthalene (2-MNAP) at rates of up to 25 μM day(−1) was established. Degradation was inhibited in the presence of molybdate and ceased in the absence of sulfate. As much as 87% of 2-[(14)C]MNAP was mineralized to (14)CO(2). 2-Naphthoic acid (2-NA) was detected as a metabolite, and incubation with either deuterated 2-MNAP or [(13)C]bicarbonate indicates that 2-NA is the result of oxidation of the methyl group. Also detected were carboxylated 2-MNAPs, suggesting the presence of an alternative pathway for 2-MNAP degradation.