12/20/2013
Transformation of Perfluorinated
Compounds during Enzyme Catalyzed
Oxidative Humification Reactions
Qi Luo1,2, Rashmi Singh Sidhu2, Qingguo Huang1,2
1Interdisplinary
Toxicology Program, University of Georgia
Athens, GA 30605
2Department of Crop and Soil Sciences, University of
Georgia
Griffin, GA 30223
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Background
• Perfluorinated compounds
(PFCs) are used in various
applications due to its special
properties
• PFCs are persistent
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Background
• Toxicity
– Increase liver and kidney weight in rats
– Carcinogenic to liver and pancreas in rats
– etc.
• EPA emerging contaminants list
• No practical remediation approaches
• enzyme- catalyzed oxidative humification
reactions (ECOHR) may provide feasible
solution
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Objective
• Determine the optimal reaction condition for
removal of PFCs by enzyme- catalyzed oxidative
humification reactions (ECOHR)
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1. Background
2. Objective
3. Enzyme-catalyzed humification reaction
4. Experiment – batch study
5. Thoughts
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ECOHR
• Enzyme-catalyzed oxidative reactions systems
Radical
•
•
•
•
ECOHR
Lignin
White rot fungi
Lignolytic enzymes
Mediator
–Peroxidases
–Laccase
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ECOHR
• Enzyme-catalyzed oxidative reactions systems
• Persistent organic pollutants
• PAHs
• PCBs
• PFOA
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ECOHR – Induced PFOA Reaction
Perfluorooctane acid (PFOA)
•
Three Components for
ECOHR Process
• Laccase
• Mediator
• O2
Colosi et al., Environ. Tox. Chem., 2009
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1. Background
2. Objective
3. Enzyme-catalyzed humification reaction
4. Experiment –batch study
5. Thoughts
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PFOA Removal Under Different
Conditions
pH 3 (citrate buffer)
1-20
pH 4 (citrate buffer)
1-20
1-0
120
PFOA Residue (%)
PFOA Residue (%)
120
1-0
90
60
30
0
10
20
30
Time (d)
40
50
90
60
30
0
10
20
30
40
50
Time (d)
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PFOA Removal Under Different
Conditions
pH 4.5 (culture medium)
1-20
pH 4 (citrate buffer)
1-0
1-20
120
PFOA Residue (%)
120
PFOA Residue (%)
1-0
90
60
90
60
30
30
0
10
20
30
Time (d)
40
50
0
10
20
30
40
50
Time (d)
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PFOA Residue (%)
1-20
Mediator
Concentration
60
30
10
20
40
Enzyme
Activity
50
Time (d)
1-20
1-2
30
20
10
0
10
30
20
30
Time (d)
40
50
Laccase activity (U/mL)
HBT Concentrationm (µM)
90
40
0
PFOA
Residue
1-0
120
0
1-20
50
1-2
1-2
1-0
1.6
1.2
0.8
0.4
0
0
10
20
30
40
50
Time (d)
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1. Background
2. Objective
3. Enzyme-catalyzed humification reaction
4. Experiment – batch study
5. Thought
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Thoughts…
• PFOA can be degraded gradually in aqueous
solution via laccase-mediated ECOHR with the
presence of mediator.
• Removal efficiency of PFOA is highly dependent
on the reaction conditions such as cation, and
mediator concentration.
• Current work is needed to carry on to monitoring
further degradation of PFOA and other factors
such as ion strength, mediator species need to be
tested.
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Acknowledgments
• SERDP: ERSON-11-02 “IN SITU
REMEDIATION OF PERFLUOROALKYL
CONTAMINATED GROUNDWATER”
• AFCEC: “IN-SITU ENZYMATIC OXIDATIVE
TREATMENT FOR PERFLUORINATED
COMPOUNDS”
• Dr. Qingguo (Jack) Huang (University of Georgia)
• Dr. Dora Chiang (AECOM)
• Mr. Dave Woodward (AECOM)
• Dr. Junhe Lu (Nanjing Agricultural University)
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Questions & Suggestions
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