Inhibitory effects of pentachlorophenol on wastewater biofilms as determined by phospholipid analysis and microelectrode

To elucidate the toxic effect of pentachlorophenol (PCP) on the microbial activities of biofilms, we used two methods to evaluate the inhibition caused by PCP. The spatial distribution of phospholipids in biofilms was determined by phospholipid analysis combined with the micro-slicing technique. The inhibition was derived from the reduction in total phospholipid concentrations on the basis of the phospholipid profile in biofilms before and after exposure to PCP. Moreover, using O2 microprofiles as bases, we determined the spatial distributions of the net specific O2 respiration in biofilms with and without exposure to PCP. Furthermore, the inhibition was derived from the reduction in respiratory rates in biofilms. We attribute the discrepancy in results from the two methods to the delay of the loss of phospholipids compared with the decrease in the oxygen uptake rate in response to PCP.

► We examine the phospholipids profiles in biofilms exposed or unexposed to inhibitor.
► We examine the O2 respiration profiles in biofilms exposed or unexposed to inhibitor.
► Reduction in total phospholipid and O2 respiration were used to evaluate inhibition.
► We found the discrepancy in results from two methods.
► We attribute it to the delay of loss of phospholipids to decrease in O2 respiration.