Assessment of continuous biodegradation of commercial PCB formulations

Conclusion

The bench scale test demonstrates that substrate availability in the growth medium can significantly effect the biodegradation pattern of commercially formulated PCBs. Under limited substrate supply, all seven major components of Aroclor 1221 were degraded by P. sp. 7509. With excessive amounts of nutrient, however, some preferences for given components were observed. The position of chlorine substitution on the biphenyl molecule appears to be one of the major factors determining an isomer's biodegradability. The biodegradation rate of higher chlorinated PCB formulations was much slower under the continuous loading. However, significant degradation of such formulations did occur, when the fermentor was switched to batch operation.