Assessment of azo dyes degradation potential of Bacillus sp. 2p and Alcaligenes faecalis 3d: a sustainable and eco-friendly alternative for dyes waste management

Abstract

The release of uncontrolled disposal of toxic chemical textile effluents containing toxic chemicals, including azo dyes, into water streams and lakes poses life-threatening risks to humans and animals. The use of microorganisms over chemicals is the best choice to eradicate such toxic chemicals from the ecosystem. The current study proves that bacterial species are excellent remediators of environmental pollutants, including azo dyes. The consortia of aerobic and anaerobic bacterial isolates provided commendable decolorization indices of 8–15 % and 10–14 %, respectively. At a large scale, Bacillus sp. 2p efficiently decolorized dye by 70 %, while 68 % was the noted decolorization percentage for Alcaligenes faecalis 3d after 8 days of incubation. The assessment of degraded products by thin-layer chromatography gave the Rf values of 0.92 and 0.98 by Bacillus sp. 2p and 0.93 by Alcaligenes faecalis 3d. The analyzed Rf value of the control was 0.94. When compared, the retention times of the control and treated samples observed by high-performance liquid chromatography proved that decolorization might have occurred to a greater extent. Moreover, Fourier Transform Infrared spectroscopic analysis of the control and the treated samples exhibited a bond reduction in the latter, providing differential biodegradation results. Then, gas chromatography-mass spectrometric analysis of the fluid acquired from the degradation of the microorganisms showed the release of compounds such as pyrrole, pyrazine-1,4-dione, 3-aminobutanoic acid, and palmitic acid. The microbial toxicity testing on Bacillus sp. 2p indicated negative results, as there was no visual clearing zone around the microbial colonies. The negative impact of bacterial-degraded wastewater on the Vigna radiata seeds showed that the bacterially decolorized water could be an alternative for the irrigation of crops to decrease the scarcity of freshwater.