Media Optimization for the Decolorization of Distillery Spent Wash by Biological Treatment using Pseudomonas Fluorescence

The wastewater released from distilleries and fermentation industries are the major source of soil and aquatic pollution due to presence of water-soluble recalcitrant colouring compounds called melanoidins. Biological decolourisation of of these compounds found more advantages compared to chemical treatments. Hence in this study, the bacterium Pseudomonas fluorescens showing higher decolorization efficiency on distillery spent wash was screened. Physico-chemical properties like colour, pH, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), etc., were analyzed for the substrate. Effect of carbon and nitrogen supplementation on media was studied followed by media optimization for different carbon, nitrogen and salt concentrations were carried out using Response Surface Methodology. The central composite design (CCD), consisting of a three-factor-four-level pattern with 17 design points, was then conducted in this optimum vicinity to locate the true optimum concentrations which are as follows: Glucose (0.8%), Peptone (0.8%) and KH2Po4 (0.05%). Hence it is found that higher decolorization of distillery spent wash could be achieved at low carbon and nitrogen concentrations. Thus this bacterium can be utilized for melanoidin decolorization of distillery effluent at industrial scale.