Removal of nitriles from synthetic wastewater by acrylonitrile utilizing bacteria.

This study describes the ability of two bacteria strains, isolated from an ABS resin manufacturing wastewater treatment system, to remove high acrylonitrile concentrations. Straight chain aliphatic nitrile compound (propionitrile, allyl cyanide); branch chain aliphatic nitrile compound (isobutyronitrilc) and aromatic nitrile compound (benzonitrile) removal by Comamonas testosteroni and Acidovorax sp. was also investigated. The results are: Comamonas testosteroni and Acidovorax sp. can remove acrylonitrile completely up to 1904.8 mg/L within 66.6 h and 1538.5 mg/L within 143.3 h, respectively. Comamonas testosteroni degraded acrylonitrile faster than Acidovorax sp., and accumulated much more acrylic acid in the medium than Acidovorax sp. The addition of acrylamide to the medium was removed by Comamonas testosteroni and Acidovorax sp. Both strains utilized acrylic acid, a metabolic by-product of acrylonitrile, as a carbon source and ammonium nitrogen, a metabolic by-product of acrylonitrile, as a nitrogen source for growth. Comamonas testosteroni and Acidovorax sp. removed propionitrile completely up to 1352.8 mg/L and 975.7 mg/L within 166.9 h, respectively. With isobutyronitrile as a substrate, more than 97.8% could be removed within 169.8 h by Comamonas testosteroni up to 1352.8 mg/L, and by Acidovorax sp. up to 975.7 mg/L. These two strains could remove allyl cyanide completely up to 775 mg/L within 49.1 h and benzonitrile completely up to 442.7 mg/L within 31.1 h. Because Comamonas testosteroni and Acidovorax sp. have good degrading ability for removing nitrile compounds they are expected to play an important role in the treatment of nitrile compounds.