Decolorization of Dyehouse Effluent and Biodegradation of Congo Red by Bacillus thuringiensis RUN1

O. D. Olukanni, A. A. Osuntoki, A. O. Awotula, Dayanand Kalyani, G. O. Gbenle, S. P. Govindwar

Research output: Contribution to journalJournal articleResearchpeer-review


A dye-decolorizing bacterium was isolated from a soil sample and identified as Bacillus thuringiensis using 16S rRNA sequencing. The bacterium was able to decolorize three different textile dyes, namely, Reactive blue 13, Reactive red 58, and Reactive yellow 42, and a real dyehouse effluent up to 80-95% within 6 h. Some non-textile industrially important dyes were also decolorized to different extents. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometer analysis of the ethyl acetate extract of Congo red dye and its metabolites showed that the bacterium could degrade it by the asymmetric cleavage of the azo bonds to yield sodium (4-amino-3-diazenylnaphthalene-1-sulfonate) and phenylbenzene. Sodium (4-amino-3-diazenylnaphthalene-1-sulfonate) was further oxidized by the ortho-cleavage pathway to yield 2-(1-amino-2-diazenyl-2-formylvinyl) benzoic acid. There was induction of the activities of laccase and azoreductase during the decolorization of Congo red, which suggests their probable role in the biodegradation. B. thuringiensis was found to be versatile and could be used for industrial effluent biodegradation.
Original languageEnglish
JournalJournal of Microbiology and Biotechnology
Issue number6
Pages (from-to)843-849
Publication statusPublished - 2013
Externally publishedYes


  • azo bonds cleavage
  • dyehouse effluent
  • effluent biodegradation
  • enzyme activity
  • Genbank sequence data
  • Eubacteria Bacteria Microorganisms (Bacteria, Eubacteria, Microorganisms) - Endospore-forming Gram-Positives [07810] Bacillus thuringiensis species strain-RUN1
  • 2-(1-amino-2-diazeny1-2-formylvinyl) benzoic acid
  • azoreductase 9029-31-6
  • Congo Red 573-58-0 pollutant, water pollutant
  • Congo red dye metabolite
  • ethyl acetate 141-78-6
  • laccase 80498-15-3 EC
  • phenylbenzene
  • Reactive blue 13 pollutant, water pollutant
  • Reactive red 58 pollutant, water pollutant
  • Reactive yellow 42 pollutant, water pollutant
  • sodium(4-amino-3-diazenylnaphthalene-1-sulfonate
  • 03502, Genetics - General
  • 10802, Enzymes - General and comparative studies: coenzymes
  • 31000, Physiology and biochemistry of bacteria
  • 31500, Genetics of bacteria and viruses
  • 37014, Public health - Sewage disposal and sanitary measures
  • 37015, Public health - Air, water and soil pollution
  • 39008, Food microbiology - General and miscellaneous
  • Biochemistry and Molecular Biophysics
  • Sanitation
  • 16S rRNA sequencing laboratory techniques, genetic techniques
  • Fourier transform infrared spectroscopy laboratory techniques, spectrum analysis techniques
  • gas chromatography-mass spectrometer analysis laboratory techniques, spectrum analysis techniques, chromatographic techniques
  • Bioprocess Engineering
  • Molecular Genetics
  • Waste Management

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