Biodecolorization of biogas plant effluent derived from anaerobically digested distillery wastewater by naturally selected Pseudomonas putida.

Effluent from biogas plants can contribute to serious environmental issues due to its high organic compound content and its dark color. This study utilizes Pseudomonas putida strains isolated from activated sludge in a wastewater treatment plant to reduce the organic compound content and dark color of biogas plant effluent. The treatment of effluent from the anaerobic digestion of distillery wastewater with P. putida in the best evaluated conditions (sample concentration of 50% v/v, agitation and aeration rates of 250 rpm and 1.0 vvm for 6 days) produced significant decolorization and organic removal efficacies of 34.29 ± 0.87% and 38.94 ± 0.63%, respectively. Bioremediation efficiency was dependent on bacterial growth, and the organic content and dissolved oxygen in the sample during cultivation were key factors in bacterial growth. The naturally selected bacterium could tolerate relatively high levels of organic content and work synergistically with other indigenous microorganisms found in the biogas plant effluent. Therefore, the bioremediation of biogas plant effluent using naturally selected P. putida can feasibly be applied in biogas power plants where sterilization is not necessary.