Orange-G Tolerance, Utilization And Degradation Potentials Of Native Bacterial Isolates

C. Mariappan*¹, T. V. Gayathri Devi¹, R. L. Yamuna¹, R. Palaniappan² and T. Selvamohan²

¹Post Graduate Department of Microbiology, Sivanath Aditanar College Pillayarpuram- 629 501 (India).

²Post Graduate Department of Microbiology, Sri Paramakalyani College Azhwarkurichi- 627 412 (India).

ABSTRACT: Soil and sediment sample obtained from Orange-G dye contaminated habitat was screened for heterotrophic bacterial population. Consistently, high heterotrophic bacterial density was recorded to the tune of 107 CFU/g. Six isolates comprising of three Pseudomonas sp. two Escherichia sp. and one Bacillus sp. were checked for Orange-G tolerance and utilization. All the bacterial strains were found to resist the azo dye, Orange-G up to 75 ppm. Above this concentration, only Pseudomonas sp. SACO3, Bacillus sp. SACo1 and Escherichia sp. SAC01 were able to tolerate. All the test bacterial strains were found to utilize Orange-G as a sole carbon and / or nitrogen source with distinctive decoloration. While the pH optima of these strains ranged from 8 to 10, their temperature optima was 37°C except for Escherichia sp. (44°C). In accordance with the abundant occurrence in the soil ecosystem, Pseudomonas sp. were found to decolorize orange-G more effectively that other strains.

KEYWORDS: Azo dyes; Orange-G; Decoloration; Pseudomonas sp.; Bacillus sp.; Eschericia sp.

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