Decolourisation of textile wastewater and bioelectricity generation in microbial fuel cell by Lysinibacillus Fusiformis ZB2

Abstract

One of the major priorities of developing countries worldwide is wastewater treatment and renewable energy production. Contamination resulting from industrial activities such as azo dyes from textile industries is a major concern. Conventional methods used in azo dye removal are costly and ineffective. In view of this, bioremediation is considered to be a good alternative where the microorganisms acclimatised to the toxic environment in the waste by degrading the pollutants. This study employs the potential of a bacterial strain Lysinibacillus fusiformis ZB2 previously isolated from textile industrial effluent and fully sequenced to decolourise azo dye and generate electricity from the decolourisation of textile wastewater in a two component mediator and mediator-less Microbial Fuel Cell (MFC). Effluent in the anode compartment was analysed for COD, colour, pH, OD600 nm and toxicity. Acid orange 7 (AO7) was the model dye and decolourisation was performed under a broad range of environmental conditions. The optimum pH, temperature and inoculum size were 5 – 8 pH units, 37 °C and 10 % respectively. Decolourisation was better under static (88 %) than agitated condition. At dye concentration above 200 mg/L growth and decolourisation decreases. Yeast extract was found to be a good co-substrate for decolourisation than glucose. AO7 decolourisation was confirmed by the presence of sulphanilic acid in the High Performance Liquid Chromatography (HPLC) peaks. Treatment of textile wastewater was better in the mediator –less MFC. The maximum voltage, power and current density generated in the mediator MFC are 0.677 V, 51.17 mW/m2 and 68.14 mA/m2. The bacteria also reduce the toxicity of the wastewater by 37 %. ANOVA test between control and sample was 99.9% significant at (p < 0.05). In conclusion, the bacteria have a good potential to treat textile wastewater however electricity generation was achieved only in the presence of a mediator