Deportation of melanoidin in distillery spent wash using bacterial consortia - confirms through structural changes and ao-eb fluorescence

Distillery spent wash maintains very dark brown color even after aerobic and anaerobic treatment due to the available of various organic and inorganic residues, obstinate and coloring compounds mainly melanoidin. In this study, melanoidin decolorizing bacterial strains were isolated and enhanced the growth rate of selected bacterial colonies at normal incubation temperature at laboratory conditions. The optimal decolourization of melanoidin was achieved at pH 7 and temperature is 37ºC on 3rd day of refinement. The phytotoxicity evaluation with mung bean (Vigna radiata) using two concentrations 1% and 5% revealed that the raw distillery effluent was environmentally highly toxic as compared to biologically treated distillery effluent, which indicated that the effluent after bacterial treatment is environmentally safe. This denotes the isolated bacterial strains competed to degrade and detoxification of melanoidin from the distillery effluent. Initially screening of 3 different bacterial strains were done in liquid cultures and were used as consortium for biosorption experiments and they have showed different decolourization ability. The minimum percentage in the consortium was observed on the first day by 14% and it increased up to 95% on the eighth day. The HPLC analysis of dye before and after degradation has five peaks during the retention time 3.00 and 6.50 min, whereas degradation products showed peaks at lower retention time, probably due to degradation of dye into small intermediate products. The melanoidin degrading products and growth population of bacterial strains were analysed by using UV- Visible Spectrometric, High Performance Liquid Chromatography (HPLC) and structural characterization through Scanning Electron Microscopy (SEM), Confocal Laser Scanning Microscopy (CLSM).