Isolation of Micrococcus sp. strain 2A from the ocean and its biodegradation of 1-naphthol in wastewater

1-Naphthol is an important raw material for organic synthesis such as pharmaceuticals, pesticides, dyes, and also the main metabolite of pesticide carbaryl and naphthalene, as well as a common aromatic pollutant in the environment. Microorganisms are the main driving force responsible for the degradation and transformation of 1-naphthol in the environment. Although many 1-naphthol degrading strains have been reported, strain resources with strong environmental adaptability and degradation ability from the marine environment are still relatively scarce. In this study, a 1-naphthol-degrading bacterial strain, Micrococcus sp. strain 2A, was isolated from seawater. The strain completely degraded 1-naphthol by co-metabolism under strong alkaline (pH = 11) and high salt (4 M NaCl) conditions. 1,2-Dihydroxynaphthalene, 2-hydroxychromene-2-carboxylate, 2-hydroxybenzal pyruvate, salicylaldehyde, and salicylate were identified during 1-naphthol degradation. The functional gene orf2030 responsible for the initial degradation of 1-naphthol was also postulated by genome sequencing and comparative proteome analysis. The bioaugmentation test showed that strain 2A could completely remove 0.3 mM 1-naphthol in the wastewater within 144 h. Our study not only enriches the theory of marine microbial metabolism of 1-naphthol but also provides strain resources and technical reserves for the bioremediation of 1-naphthol in high salinity and strong alkaline fine chemical synthetic wastewater.