Revealing degradation strategy of aniline blue by Lysinibacillus sp. 38-6 via genomic analysis

Aniline blue, a triphenylmethane dye, has been widely used in industrial and medical fields, leading to its gradual enrichment in environmental water. Its removal and degradation from the water is essential but very challenging. A bacterium Lysinibacillus sp. 38-6, which is able to efficiently degrade aniline blue, was isolated from the surface soil samples under withered leaves. The strain exhibited excellent decolorization capacity at high concentrations of aniline blue (91% at 1000 mg/L) and salt (90% at 75 g/L) as well as high temperature (92% at 45°C). To investigate the dye degradation strategies of Lysinibacillus sp. 38-6 at the genomic level, its genome was sequenced and analyzed. The isolate possesses abundant genomic features responsible for degrading dyes. In particular, several genes encoding laccase, iron-dependent peroxidase, NAD(P)H-dependent FMN reductase and short chain dehydrogenase/reductases might contribute to the cleavage of chromophore groups and aromatic rings in aniline blue. In addition, a number of genes required for heat, salt and oxidative stress responses were found, indicating that Lysinibacillus sp. 38-6 is able to efficiently degrade dyes at higher temperature, salty and oxidative environments. It is thus inferred that isolate 38-6 has the potential for applications in efficient degradation of aniline blue in wastewater treatment.