Studies on Decolourisation of Acid Blue 113 Using Staphylococcus Aureus and Escherichia Coli Isolated From Tannery Wastewater

Abstract

Biodegradation of acid blue 113 has been studied using two strains-Staphylococcus aureus and Escherichia coli. The effect of pH, time, initial dye concentration, the inoculum size, the co-substrate, static and shaking on decolourisation was studied. The optimum condition for decolourisation was found to be at pH 7 for an initial dye concentration of 200 mg/L at 37 ̊C under static condition. The removal of dye by S.aureus and E.coli at optimum condition was 90% and 88% within 30 h and 42 h respectively. Addition of fructose and starch as carbon source increased the removal of colour by S.aureus and E.coli respectively. Similarly addition of ammonium formate and glycine as nitrogen source under static condition increased the colour removal by S.aureus and E. coli. The enzyme activity of azoreductase for S. aureus and E. coli was found to be 7.33 U/ml and 7.24 U/ml respectively. The COD reduction, FTIR and TLC analysis of the sample before and after decolourisation confirmed the biodegradation of dye and the formation of new metabolite. Phytotoxicity studies indicated that the microbial treated effluent is safe for disposal into the environment. .

Decolorization of azo dyes with Klebsiella Pneumoniae under high saline conditions

“…Peak at 2314.58 cm -1 represents the CN stretch [54]. Control dye has a peak at 3387.09 cm -1 due to the presence of 2 c amine and OH stretching [54], [193]. This peak broadened from 3100 cm -1 to 3500 cm -1 supporting the increase of hydroxyl and amine functional groups in the degraded products [93], [130].…”

“…Compared with the FT-IR spectra of dye standard (data shown in Figure 4.9), 24 h treated sample had a broad peak in the region 2600 -3703 cm -1 , indicating the presence of phenolic hydroxyl and carboxyl groups because of degradation [93], [131]. Peaks at 1552.7 cm -1 and 1344.38 cm -1 in the dye associated with the azo bond [193] and C-N stretch [145] respectively wholly disappeared in the 24 h treated sample. The former indicates the reduction of the chromophore and formation of amines.…”

“…The appearance of new peaks in treated samples at 918.12 cm -1 , 1278.1 cm -1 , 1649 cm -1, and 3242. 34 cm -1 representing C-O stretch, asymmetric C-O-C stretch [131], aryl carboxylic acid or quinone [193] and N-H stretch in amides [145] respectively, pointed towards the formation of metabolites. Also, 461 cm -1 in dye spectrum has shifted to 503.42 cm -1 in the treated sample.…”