Isolation and characterization of Aeromonas aquariorum from a dye effluent and its effect in bioaugmentation

Trypan Blue, a diazo dye and synthetic organic colourant, is commonly used in several textile and printing industries. A substantial portion of such dyes are recalcitrant and carcinogenic which are disposed of untreated in the environment. In this investigation, water sample in which such textile effluents are disposed of was used as a source of isolating a unique bacterium in vitro which was characterized and 16S rDNA gene sequencing was carried out. It was identified to be similar to Aeromonas aquariorum strain N2 based on nucleotide homology and phylogenetic analysis. This Gram negative short rod bacterium was seen to be degrading the dye to non-hazardous compounds including simpler hydrocarbons. Spectrophotometric analysis and SDS-PAGE techniques were performed to give conclusive evidence for the presence of the enzymes responsible for this. Characterization of the effluent with Gas Chromatographic technique indicated the degradation of the active component. The enzymatic profile revealed the enhanced expression of Azoreductase, Alkane Hydroxylase and Catechol 1, 2-dioxygenase in the presence of the dye. This paper narrates the detailed action of the above mentioned bacterium responsible for enzymatic degradation of a foreign pollutant which paves way for safe treatment of colouring agents.