Degradation of acetonitrile and biphenyl compounds by a mixed microbial culture

Abstract

A mixed microbial culture was isolated from an environment contaminated with organic cyanides and polychlorinated biphenyls (PCBs). This mixed culture could utilize acetonitrile as the sole source of carbon and nitrogen, and biphenyl as the sole source of carbon. This mixed culture also utilized nitriles, their respective amides, and several PCBs as growth substrates. Studies involving the radiolabeled compounds indicated that nearly 70% of [14C]acetonitrile and 51% of [14C]biphenyl were recovered as 14CO2. The end products resulted during the degradation of acetonitrile and biphenyl were identified as ammonia and benzoate, respectively. It was also observed that the mixed culture that can degrade biphenyl loses its capability when transferred repeatedly into a medium supplemented with acetonitrile as growth substrate. The present study suggests that the application of mixed rather than pure microbial culture is more effective in bioremediation of toxic chemicals.