SYNERGISTIC MINERALIZATION OF BIPHENYL BY ALCALIGENES-FAECALIS TYPE-II BPSI-2 AND SPHINGOMONAS-PAUCIMOBILIS BPSI-3

Polychlorinated biphenyls (PCBs) are important environmental pollutant s and have been found to have adverse effects on a number of different organisms. Aerobic biodegradation of PCBs occurs through direct oxida tion of the biphenyl nucleus. Biphenyl degraders are instrumental in t he mineralization of PCBs to CO2 and water. Here two bacteria, Alcalig enes faecalis type II strain BPSI-2 and Sphingomonas paucimobilis stra in BPSI-3, are described that exhibit synergistic mineralization of bi phenyl (using C-14-UL-biphenyl) when grown as a co-culture. Mineraliza tion rates (23.7 and 9.1 nmol nmol(-1) h(-1), respectively) and extent of mineralization (38.1% and 24.4%, respectively) were significantly different between the strains as well as when compared to the co-cultu re (35.2 nmol nmol(-1) h(-1) and 45.2%). Both strains were originally isolated from an enrichment culture, BSEN-2. The coculture of BPSI-2 a nd 3 showed a threefold increase in mineralization rate compared with the parent culture and a decrease in the time taken for (CO2)-C-14 evo lution to occur. There was no significant difference in the extent of mineralization between the co-culture and BSEN-2. Examination of enric hment cultures at the community level may play a role in optimizing bi oremediation programmes.