Use of microelectrodes to investigate the effects of 2‐chlorophenol on microbial activities in biofilms

Abstract

In order to assess the applicability of using microelectrodes as a tool for inhibition tests, temporal and spatial inhibitory effects of 2-chlorophenol (2-CP) on O 2 respiration and nitrification activities in municipal wastewater biofilms were investigated using microelectrodes for O 2 and NH 4 þ . The time-course microelectrode measurements demonstrated that 2-CP inhibited O 2 respiration and nitrification activities within 6-18 min. The microbial activities were inhibited only in the upper 400 mm of the biofilms by 2-CP, and the bacteria present in the deeper parts of the biofilms were still active, probably due to limited penetration of 2-CP. These results could reasonably explain the difference in inhibitory ratios of the O 2 respiration and nitrification activities in the biofilms. O 2 respiration activity was incompletely inhibited, which was attributed to the presence of O 2 respiration activities in the deeper parts of the biofilm. In contrast, nitrification activity was significantly inhibited because ammonia-oxidizing bacteria were present in the upper parts of the biofilm. These results indicate that the microelectrodes with a very quick response time and a high spatial resolution are useful tools to study temporal and spatial inhibitory effects of inhibitors on in situ microbial activities in biofilms. ß 2005 Wiley Periodicals, Inc.

Algal bioactive compounds reduce net oxygen fluxes of artificial diatom biofilms

“…We measured the oxygen community metabolism with microelectrodes to check the effect of toxic compounds on biofilms as performed by Satoh et al (2005). Our goal was to show that this approach can also be applied successfully for the study of the effect of natural bioactive compounds.…”

Simultaneous removal of 2-chlorophenol, phenol, p-cresol and p-hydroxybenzaldehyde under nitrifying conditions: Kinetic study

“…The mass balance suggested that 2-chlorophenol was mainly mineralized (82%). Satoh et al (2005) evaluated the effect of 10 mg/L of 2-CP on nitrifying biofilm, observing that this compound inhibited the aerobic respiration and 2-CP consumption. On the other hand, Martí-nez-Hernández et al (2011) also evaluated the effect of 2-CP on nitrification process, using nitrifying sludge physiologically stable without previous exposition to any phenolic compound.…”

2-Chlorophenol consumption and its effect on the nitrifying sludge

“…The 2-CP specific consumption rate was 0.001 ± 0.0001 mg 2-CP-C (mg protein-d) −1 . Satoh et al [9] evaluated the effect of 2-CP (10 mg L −1 ) on a nitrifying biofilm, finding that both O 2 and nitrifying consumption rates were inhibited and the 2-CP was not consumed by the biofilm. These results are contrasting with our assays, as the nitrifying sludge was able to consume the 2-CP.…”

“…Nevalainen et al [8] studied the elimination of 2,4,6-trichlorophenol (2,4,6-CP) using a nitrifying fluidized-bed reactor, reporting the removal of 2,4,6-CP, but neither the ammonia specific consumption rate nor nitrifying yield values were determined. Satoh et al [9] evaluated the effect of 2-CP on a nitrifying biofilm, observing a decrease in oxygen and ammonium consumption rate and no 2-CP consumption. The objective of this work was to determine the effects of 2-CP on the nitrifying sludge using response variables such as specific rates and yields as well as to obtain evidences of the level to which this compound acts.…”