Paracoccus denitrificans SD1 mediated augmentation with indigenous mixed cultures for enhanced removal of N,N-dimethylformamide from industrial effluents

Abstract

Bioaugmentation is an effective treatment method to reduce recalcitrant pollutants from polluted sites. Dimethylformamide (DMF) is a very common toxic organic solvent among the effluents of textile and pharma industries. DMF was degraded by pre-adapted Paracoccus denitrificans SD1 with indigenous mixed cultures in both bioaugmentation and non-bioaugmentation conditions. In free cell condition, augmentation was not much significant due to competition among the bacterial cells and direct exposure of cells to toxic level of DMF. To enhance the degradation of DMF, cells were entrapped in PVA-alginate matrix individually and collectively for bioaugmentation experiments. Bioaugmentation is successful when immobilized P. denitrificans SD1 is introduced higher inoculum volume with indigenous cultures in continuous packed bed reactor system. This treatment has succeeded in removing 91.3% of 3% (v/v) DMF from the industrial effluent. This investigation advocates that bioaugmentation enhances the DMF removal efficiency by about 20% when compared to individual degradation by P. denitrificans SD1. (C) 2013 Elsevier B.V. All rights reserved.