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1968210 
Journal Article 
Methylation is the initial reaction in anaerobic naphthalene degradation by a sulfate-reducing enrichment culture 
Safinowski, M; Meckenstock, RU 
2006 
Yes 
Environmental Microbiology
ISSN: 1462-2912
EISSN: 1462-2920 
8 
2 
347-352 
English 
16423020 
WOS:000234647600014 
The sulfate-reducing culture N47 can utilize naphthalene or 2-methylnaphthalene as the sole carbon source and electron donor. Here we show that the initial reaction in the naphthalene degradation pathway is a methylation to 2-methylnaphthalene which then undergoes the subsequent oxidation to the central metabolite 2-naphthoic acid, ring reduction and cleavage. Specific metabolites occurring exclusively during anaerobic degradation of 2-methylnaphthalene were detected during growth on naphthalene, i.e. naphthyl-2-methyl-succinate and naphthyl-2-methylene-succinate. Additionally, all three enzymes involved in anaerobic degradation of 2-methylnaphthalene to 2-naphthoic acid that could be measured in vitro so far, i.e. naphthyl-2-methyl-succinate synthase, succinyl-CoA:naphthyl-2-methyl-succinate CoA-transferase and naphthyl-2-methyl-succinyl-CoA dehydrogenase were also detected in naphthalene-grown cells with similar activities. Induction experiments were performed to study the growth behaviour of the cell when transferred from naphthalene to 2-methylnaphthalene or vice versa. When the cells were transferred from naphthalene to 2-methylnaphthalene they grew immediately, indicating that no new enzymes had to be induced. On the contrary, the transfer of cells from 2-methylnaphthalene to naphthalene caused a lag-phase of almost 100 days demonstrating that an additional catabolic enzyme has to be activated in this case. We propose the methylation as a novel general mechanism of activation reactions in anaerobic degradation of unsubstituted aromatic hydrocarbons. 
Environmental Pollutants; Naphthalenes; naphthalene; 2166IN72UN; 2-methylnaphthalene; S8MCX3C16H; Index Medicus; Anaerobiosis; Biodegradation, Environmental; Methylation; Naphthalenes -- chemistry; Environmental Pollutants -- analysis; Naphthalenes -- analysis; Sulfur-Reducing Bacteria -- growth & development