Premium
Kinetics of polychlorinated biphenyl dechlorination and growth of dechlorinating microorganism
Author(s) -
Rhee G.Yull,
Sokol Roger C.,
Bethoney Charlotte M.,
Cho YoungCheol,
Frohnhoefer Robert C.,
Erkkila Ted
Publication year - 2001
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620200405
Subject(s) - polychlorinated biphenyl , environmental chemistry , biphenyl , microorganism , chemistry , environmental science , biology , bacteria , organic chemistry , genetics
The present study has investigated a correlation between the kinetics of polychlorinated biphenyl (PCB) dechlorination and the growth of dechlorinating microbial populations. Microorganisms were eluted from Aroclor® 1248‐contaminated St. Lawrence River (NY, USA) sediments and inoculated into clean sediments spiked with Aroclor 1248 at 10 concentrations ranging from 0 to 3.12 μmol/g sediment (0–900 ppm). The time course of PCB dechlorination and population growth were concurrently determined by congener‐specific analysis and the most probable number technique, respectively. The specific growth rate was a saturation function of PCB concentrations above the threshold concentration (0.14 μmol/g sediment, or 40 ppm), below which no dechlorination or growth of dechlorinations were observed. The maximum growth rate was 0.20/d with a half‐saturation constant of 1.23 μmol/g sediment. The yield of dechlorinating microorganisms showed a peak at 0.70 μmol/g sediment (200 ppm), with a value of 10.3 × 10 12 cells/mol Cl removed, and decreased below and above this concentration. The dechlorination rate (μmol Cl removed/g sediment/d) was a linear function of Aroclor concentration. Both the log of this rate and the maximum level of dechlorination were significantly correlated with growth rate. The biomass‐normalized dechlorination rate (μmol Cl removed/g sediment/cell/d) was first order because of the exponential manner of the population growth. The first‐order rate constant was a saturation function of Aroclor concentrations, with a maximum of 0.24/d (a half‐life of 2.9 d) and a half‐saturation constant of 1.18 μmol/g sediment, which are similar to the constants for growth. These results indicate that the dechlorination rate is tightly linked to the population growth of dechlorinating microorganisms.