Monitoring Gene Expression To Evaluate Oxygen Infusion at a Gasoline-Contaminated Site

Increasingly, molecular biological tools, most notably quantitative polymerase chain reaction (qPCR), are being employed to provide a more comprehensive assessment of bioremediation of petroleum hydrocarbons and fuel oxygenates. While qPCR enumeration of key organisms or catabolic genes can aid in s...

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Bibliographic Details
Published in:Environmental science & technology 2010-09, Vol.44 (17), p.6829-6834
Main Authors: Baldwin, Brett R, Biernacki, Anita, Blair, Joel, Purchase, Michael P, Baker, Jeffrey M, Sublette, Kerry, Davis, Greg, Ogles, Dora
Format: Article
Language:English
Subjects:
Applied sciences
Benzene - analysis
Biodegradation
Biodegradation, Environmental
Bioremediation
California
Environmental Monitoring
Environmental Pollutants - analysis
Environmental science
Exact sciences and technology
Gasoline
Gasoline - analysis
Gene expression
Gene Expression Regulation, Bacterial
Hydrocarbons
Kinetics
Oxygen
Oxygen - analysis
Pollution
Polymerase chain reaction
Proteobacteria - enzymology
Proteobacteria - genetics
Remediation and Control Technologies
Ribonucleic acid
RNA
RNA, Messenger - genetics
RNA, Messenger - metabolism
Toluene - analysis
Xylenes - analysis
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Summary:Increasingly, molecular biological tools, most notably quantitative polymerase chain reaction (qPCR), are being employed to provide a more comprehensive assessment of bioremediation of petroleum hydrocarbons and fuel oxygenates. While qPCR enumeration of key organisms or catabolic genes can aid in site management decisions, evaluation of site activities conducted to stimulate biodegradation would ideally include a direct measure of gene expression to infer activity. In the current study, reverse-transcriptase (RT) qPCR was used to monitor gene expression to evaluate the effectiveness of an oxygen infusion system to promote biodegradation of BTEX and MTBE. During system operation, dissolved oxygen (DO) levels at the infusion points were greater than 30 mg/L, contaminant concentrations decreased, and transcription of two aromatic oxygenase genes and Methylibium petroleiphilum PM1-like 16S rRNA copies increased by as many as 5 orders of magnitude. Moreover, aromatic oxygenase gene transcription and PM1 16s rRNA increased at downgradient locations despite low DO levels even during system operation. Conversely, target gene expression substantially decreased when the system was deactivated. RT-qPCR results also corresponded to increases in benzene and MTBE attenuation rates. Overall, monitoring gene expression complemented traditional groundwater analyses and conclusively demonstrated that the oxygen infusion system promoted BTEX and MTBE biodegradation.
ISSN:0013-936X
1520-5851
DOI:10.1021/es101356t