Decolorization of amaranth RI and fast red E azo dyes by thermophilic Geobacillus thermoleovorans KNG 112

• Published in: Journal of chemical technology and biotechnology (1986) 2022-02, Vol.97 (2), p.482-489
• Main Authors: Rajashekarappa, Kotresh Kyathanahally, Mahadevan, Gurumurthy Dummi, Neelagund, Shivayogeeswar Eshwarappa, Sathynarayana, Madhuri, Vijaya, Divya, Mulla, Sikandar I
• Format: Article
• Language: English
• Subjects: Acetals; Alkanes; Alkynes; Amaranth; Amines; Aromatic compounds; azo dye; Azo dyes; biodegradation; Carbon sources; Carbonyl compounds; Carbonyls; Color removal; Decoloring; Decolorization; Decontamination; Discharge; Dyes; Fenugreek; Fourier analysis; Fourier transforms; Geobacillus thermoleovorans; Germination; Industrial pollution; Infrared analysis; Maltose; Microorganisms; Nitrosamine; Nitrosamines; Optimization; Spectral analysis; Spectrum analysis; thermophiles; Wastewater
• ISSN: 0268-2575; 1097-4660
• DOI: 10.1002/jctb.6834

BACKGROUND Accumulation of industrial dyes in wastewater creates not only environmental problems, but also medical and aesthetic problems. Removal of synthetic dyes from contaminated hot textile industrial discharge is a fundamental issue. Herein, the microbial decolorization of azo dyes amaranth RI and fast red E was studied. The decolorization process was studied in terms of various physicochemical and analytical parameters. RESULTS The azo dye decolorization efficiency was improved with beef extract and maltose as nitrogen and carbon sources, respectively. At 55 °C, Geobacillus thermoleovorans KNG 112 showed the maximum decolorization for both amaranth RI and fast red E at pH 7 and 8, respectively. Fourier transform infrared spectral analysis revealed the formation of amide, nitrosamine, aromatic and carbonyl compounds, alkyne, alkane, alcohol and alkyl halide groups after dye decolorization. Mixed dye (amaranth RI and fast red E) decolorization resulted in formation of various alkyl acetals, amines (nitrosamines, secondary and tertiary amines) azo groups and alkyl chloride. Furthermore, phytotoxic effect of azo dyes on the germination of fenugreek and green gram showed no inhibitory effects; however, more and rapid germination compared to the control group was observed. CONCLUSIONS The results lead to the conclusion that the optimization of G. thermoleovorans KNG 112 for removal of azo dyes could have applications in decontamination of hot industrial discharges. © 2021 Society of Chemical Industry (SCI).