TY - JOUR
T1 - Biodegradation of 2,4,5-trichlorophenol by aerobic microbial communities
T2 - Biorecalcitrance, inhibition, and adaptation
AU - Marsolek, Michael D.
AU - Kirisits, Mary Jo
AU - Rittmann, Bruce
N1 - Funding Information:
Acknowledgments The authors would like to thank the Institute for Environmental Catalysis at Northwestern University and the National Science Foundation for financial support, and Challenge Environmental Systems Inc. (Little Rock, AR) for use of the respirometer system.
Copyright:
Copyright 2009 Elsevier B.V., All rights reserved.
PY - 2007/6
Y1 - 2007/6
N2 - Chlorinated aromatic compounds challenge our environment and wastewater treatment processes due to their biorecalcitrance and inhibition. In particular, 2,4,5-trichlorophenol (TCP) seems to demonstrate greater resistance to biodegradation than other trichlorophenols and is a known uncoupler of the electron transport chain, although little work addresses this compound specifically. Here, we investigate the biorecalcitrance, inhibition, and adaptation to 2,4,5-trichlorophenol by aerobic mixed microbial communities. We show that 2,4,5-trichlorophenol is strongly resistant to biodegradation at concentrations greater than 40 μM, demonstrates inhibition to respiration in direct proportion to 2,4,5-trichlorophenol concentration (with 50% inhibition projected near 85 μM 2,4,5-trichlorophenol), and does not sustain biomass in continuous reactors, even when all input 2,4,5-trichlorophenol is degraded. Communities showed consistent adaptation patterns to 2,4,5-trichlorophenol at concentrations of 10 μM and 20 μM, but these patterns diverged at concentrations greater than 40 μM. Finally, thermodynamic approximations were used to estimate the yield of 2,4,5-trichlorophenol as 0.165 gVSS/gCOD, a low value that partially explains why biodegradation of 2,4,5-trichlorophenol did not sustain the biomass. In particular, we estimated that the minimum concentration to support steady-state biomass (Smin) is approximately 180 μM, a value much larger than the 40-μM concentration that is strongly resistant to biodegradation. Thus, readily biodegradable concentrations of 2,4,5-trichlorophenol are too low to sustain the biomass that biodegrades it.
AB - Chlorinated aromatic compounds challenge our environment and wastewater treatment processes due to their biorecalcitrance and inhibition. In particular, 2,4,5-trichlorophenol (TCP) seems to demonstrate greater resistance to biodegradation than other trichlorophenols and is a known uncoupler of the electron transport chain, although little work addresses this compound specifically. Here, we investigate the biorecalcitrance, inhibition, and adaptation to 2,4,5-trichlorophenol by aerobic mixed microbial communities. We show that 2,4,5-trichlorophenol is strongly resistant to biodegradation at concentrations greater than 40 μM, demonstrates inhibition to respiration in direct proportion to 2,4,5-trichlorophenol concentration (with 50% inhibition projected near 85 μM 2,4,5-trichlorophenol), and does not sustain biomass in continuous reactors, even when all input 2,4,5-trichlorophenol is degraded. Communities showed consistent adaptation patterns to 2,4,5-trichlorophenol at concentrations of 10 μM and 20 μM, but these patterns diverged at concentrations greater than 40 μM. Finally, thermodynamic approximations were used to estimate the yield of 2,4,5-trichlorophenol as 0.165 gVSS/gCOD, a low value that partially explains why biodegradation of 2,4,5-trichlorophenol did not sustain the biomass. In particular, we estimated that the minimum concentration to support steady-state biomass (Smin) is approximately 180 μM, a value much larger than the 40-μM concentration that is strongly resistant to biodegradation. Thus, readily biodegradable concentrations of 2,4,5-trichlorophenol are too low to sustain the biomass that biodegrades it.
KW - 2,4,5-trichlorophenol
KW - Adaptation
KW - Biodegradation
KW - Inhibition
KW - Recalcitrance
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U2 - 10.1007/s10532-006-9069-3
DO - 10.1007/s10532-006-9069-3
M3 - Article
C2 - 17091354
AN - SCOPUS:34247351527
SN - 0923-9820
VL - 18
SP - 351
EP - 358
JO - Biodegradation
JF - Biodegradation
IS - 3
ER -