Isolation and Characterisation of Microbial Strain AZO29 Capable of AZO Dye Decolourization

ABSTRACT

Activated sludge samples collected from wastewater treatment plant (WWTP) in textile factory “Giorgetti Bulgaria” AD were exploited for isolation of dye decolorizing bacteria. A microbial strain AZO29 was selected based on its efficiency, showing maximum and faster decolourization of textile dye Amaranth. Identification of isolate by 16SrRNA technique revealed that the microorganism were from family Pseudomonadaceae of Gammaproteobacteria (99% confidence), the closest matches found after BLAST alignment were 16S sequences of Pseudomonas strains (97% similarity). Bacterial isolate AZO29 performed 100% decolourization after 24 hours of cultivation at the presence of 700 mg.l⁻¹ Amaranth and degrade up to 1400 mg.l⁻¹ of the azo dye for 72 hours in liquid medium. The decolourization rate (r_ama) increased with respect of increase of Amaranth concentration from 0.165 to 0.265 mM. Over 90% conversion can be achieved by AZO29 for a range of azo dye concentration up to 0.265 mM.

Keywords:

• Amaranth
• microbial decolourization
• phylogenetic characterization