Characterization and Identification of Congo Red Decolorizing Bacteria from Monocultures and Consortia


Aileen C. Jalandoni – Buan1, Anna Lynn A. Decena-Soliven, Ernelea P. Cao2, Virginia L. Barraquio3, and Wilfredo L. Barraquio4†

1Outsourcing and Manufacturing Solutions, Inc. (OMSI), AFP-RSBS Industrial Park, Western Bicutan, Taguig, Metro Manila
2Natural Sciences Research Institute, College of Science,
University of the Philippines Diliman, Quezon City 1101
3Animal and Dairy Sciences Cluster (Dairy Training and Research Institute),
College of Agriculture, University of the Philippines Los Baños, College, Laguna 4031
4Institute of Biology, College of Science, University of the Philippines Diliman; †(deceased)

corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.




Congo red is a carcinogenic direct diazo dye used for the coloration of paper products. It is recalcitrant and is thus found in effluents of paper factories. Bacteria in consortia capable of decolorizing Congo red were isolated from polluted and non-polluted sites. Members of the consortia were isolated and those capable of decolorizing Congo red were selected. SB13B was the fermentative and nitrate reducing monoculture, SB12D and IRRI-1C were the fermentative monocultures and S22B was the denitrifying monoculture. The toxicity of decolorized medium and undegraded Congo red was tested on bacteria, yeast, rice, and mungbean plants. The monocultures were characterized and identified. The decolorizing activities were 97% for SB13B, 96% for SB12D, 92% for IRRI-1C and 96% for S22B. S22B and SB13B were able to degrade Congo red while reducing nitrate to nitrogen gas and nitrite. The growth of bacteria and yeast were not inhibited by both the decolorized medium and undegraded Congo red. Decolorization of Congo red by bacteria diminished the severe toxic effect of the dye to rice and mungbean plants. SB13B was identified as Escherichia coli by API 20 E, fatty acid analysis and 16S rRNA sequencing. SB12D was identified as Enterobacter dissolvens by 16S rRNA sequencing. BIOLOG and 16S rRNA sequencing identified S22B as Pseudomonas citronellolis and Pseudomonas aeruginosa by fatty acid analysis. IRRI-1C was identified as Klebsiella oxytoca using API 20 E. . . .





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