Decolourization of molasses based distillery wastewaterusing a bacterial consortium

摘要

The effluent from sugarcane molasses based distilleries leads to environmental pollution due to its largevolume and the presence of dark brown coloured compounds. In this study, a bacterial consortium isolated from waterfallsediments was selected as a molasses-decolourizing agent. The effect of culture conditions and medium composition ondecolourization activity and growth of the bacterial consortium was investigated. The bacterial consortium was able to growand decolourize molasses wastewater under facultative and anaerobic conditions in general. Aerobic culture conditions atpH 7 and 9 in molasses wastewater containing LB medium exhibited high growth but poor decolourization. The addition ofa supplementary nutrient source in molasses wastewater medium significantly increased the decolourization activity of thebacterial consortium by up to 26.5% within 48 h under anaerobic conditions. Comparison of 16S rDNA sequences indicatedthat the bacterial consortium which showed decolourization activity under aerobic conditions consisted of Acinetobactersp., Pseudomonas sp., Comamonas sp., Klebsiella oxytoca, Serratia marcescens and unidentified bacteria, whereas, theanaerobically enriched consortium consisted of Pseudomonas sp., Klebsiella oxytoca, Bacillus cereus and Citrobacterfarmeri, a mercury-resistant bacterium, and an unidentified bacterium. Denaturing gradient gel electrophoresis profilesindicated that the community structures of aerobically and anaerobically enriched bacterial consortium were different.