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Development and Application of An Alkaliphilic, Halotolerant Bacterial Consortium for the Treatment of Azo Dyes
Noshaba Hassan Malik, Misbah Khan, Ammar Ahmed, Nicolette A. Zhou, Maliha Ahmed and Naeem Ali
Abstract:
This study presents a novel application of an acclimated alkaliphilic, halotolerant bacterial consortium for treatment of a reactive azo dye mixture. Alkaliphilic, halotolerant bacteria were isolated from pretreated garden soil amended with azo dye mixture, NaCl, and NaOH. Twenty-nine bacteria were isolated, of which three demonstrated 81-85% decolorization of 50 ppm dye mixture within 24 hours. When the three isolates were combined, the consortium demonstrated 95% decolorization. Through phenotypic and 16S rRNA analysis, the isolates were identified as Oceanobacillus oncorhynchi NHHA1, Halomonas sp. H1(2016) NHHA2 and Halomonas kenyensis NHHA3. The alkaliphilic, halotolerant consortium, demonstrated 98% decolorization of the reactive azo dye mixture (50 ppm) within 24 hours at 35ºC, in mineral salt medium (pH 10, 10% [w/v] NaCl) supplemented with glucose and yeast extract (0.1% [w/v] each). The consortium showed 80-90% decolorization activity, over a wide range of pH (8-13) and NaCl concentrations (0-12% [w/v]). The consortium also exhibited an appreciable tolerance to the dye mixture (50-300 ppm). Biodegradation of the dye mixture was confirmed by characteristic band changes in the FTIR spectrum of the decolorized dye mixture. Furthermore, phytotoxicity and brine shrimp lethality assays indicated a reduction in the toxicity of the dye mixture following bacterial treatment.
Keywords:
Alkaliphilic, Halotolerant, Consortium, Azo dyes, Treatment
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