Research Interests

Environmental Microbiology, Petroleum Microbiology, Anaerobic Hydrocarbon Metabolism, Biodegradation, Bioremediation, Enhanced Energy Recovery, Sulfate Reduction, Methanogenesis

In the Gieg laboratory, we aim to understand how anaerobic microorganisms metabolize a variety of compounds associated with the energy industry (mainly hydrocarbons) that have either been accidentally released into the environment or are present in natural reservoirs.  Recent studies have shown that anaerobic microorganisms use metabolic strategies distinct from those of aerobes in order to biodegrade hydrocarbons, such as activation by fumarate addition, carboxylation, hydroxylation, and methylation.  Overall, anaerobic hydrocarbon metabolism is poorly understood. 

Using combined tools of cultivation, analytical chemistry, and molecular biology, we seek to:

1. elucidate novel anaerobic biodegradation pathways of different classes of hydrocarbons and related compounds under highly reduced conditions (e.g., sulfate-reducing and methanogenic conditions) 
2. understand the associated biochemical and enzymatic mechanisms
3. identify and isolate key consortia and species involved
4. investigate the ecological constraints on anaerobic hydrocarbon metabolism

In determining the fundamental science underlying anaerobic hydrocarbon biodegradation, we can begin to formulate universal themes of metabolism and apply what we learn to important environmental problems or energy-related systems such as:

• Anaerobic bioremediation at fuel-contaminated sites
• Enhanced energy recovery via the bioconversion of oil to methane in marginal oilfields
• Biocorrosion
• Paraffin biotreatment or prevention
• Heavy oil formation and recovery via microbial activity
• Oil sands tailings ponds reclamation
• Oil and gas souring

Courses Taught

Graduate Students

Selected publications

• Quesnel, D. M.; I. M. Bhaskar; L. M. Gieg; G. Chua. 2011. Naphthenic acid biodegradation by the unicellular alga /Dunaliella tertiolecta/. Chemosphere 84: 504-511.
• Ramos-Padrón, E.; S. Bordenave; S. Lin; I. Mani Bhaskar; X. Dong; C.W. Sensen; J. Fournier; G. Voordouw; L. M. Gieg. 2011. Carbon and sulfur cycling by microbial communities in a gypsum-treated oil sands tailings pond. Environ. Sci. Technol. 45: 439-446.
• Gieg, L. M.; I. A. Davidova; K. E. Duncan; J. M. Suflita. 2010. Methanogenesis, sulfate reduction and crude oil biodegradation in hot Alaskan oilfields. Environ. Microbiol. 12: 3074-3086.
• Callaghan, A. V., I. A. Davidova, K. Savage-Ashlock; V. A. Parisi; L.M. Gieg; J.M. Suflita, J.J. Kukor, B. Wawrik. 2010. Diversity of benzyl- and alkylsuccinate synthase genes in hydrocarbon-impacted environments and enrichment cultures. Environ. Sci. Technol. 44: 7287–7294.
• Gieg, L. M. 2010. Anaerobic Microbial Processes and the Prospect for Methane Production From Oil. In: Applied Microbiology and Molecular Biology in Oil Field Systems, Eds. C. Whitby and T. Lund Skovhus; Springer, pp. 189-192.
• Gieg, L. M. 2010. Case Study: Proof of Concept That Oil Entrained in Marginal Reservoirs Can Be Bioconverted to Methane Gas as a Green Energy Recovery Strategy. In: Applied Microbiology and Molecular Biology in Oil Field Systems, Eds. C. Whitby and T. Lund Skovhus; Springer, pp. 193-198.
• Savage, K. N.; L. R. Krumholz; L. M. Gieg; V. A. Parisi; J.M. Suflita; J. Allen; R. P. Philp; M. S. Elshahed. 2010. Biodegradation of low-molecular-weight alkanes under mesophilic, sulfate-reducing conditions: metabolic intermediates and community patterns. FEMS Microbiol. Ecol. 72: 485-495.
• Yagi, J. M.; J. M. Suflita; L. M. Gieg; C.M. DeRito; C.-O. Jeon; E. L. Madsen. 2010. Subsurface cycling of nitrogen and anaerobic aromatic hydrocarbon biodegradation revealed by nucleic acid and metabolic biomarkers. Appl. Environ. Microbiol. 76: 3124-3134.
• Duncan, K. E.; L. M. Gieg; V. A. Parisi; R. S. Tanner; J. M. Suflita; S. Green Tringe; J. Bristow. 2009. Biocorrosive thermophilic microbial communities in Alaskan North Slope oil facilities. Environ. Sci. Technol. 43: 7977-7984.
• Beasley, K. K.; L. M. Gieg; J. M. Suflita; M. A. Nanny. 2009. Polarizability and spin density correlate with the relative anaerobic biodegradability of alkylaromatic hydrocarbons. Environ. Sci. Technol. 43: 4995-5000.
• Gieg, L. M.; R. E. Alumbaugh; J. A. Field; J. Jones; J. D. Istok; J. M. Suflita. 2009. Assessing in situ rates of anaerobic hydrocarbon bioremediation. Microb. Biotechnol. 2: 222-233.
• Parisi, V. A.; G. R. Brubaker; M. J. Zenker; R.C. Prince; L. M. Gieg; M. L.B. da Silva; P. J. J. Alvarez; J. M. Suflita. 2009. Field metabolomics and laboratory assessments of anaerobic intrinsic bioremediation of hydrocarbons at a petroleum-contaminated site. Microb. Biotechnol. 2: 202-212.
  
• Gieg, L. M.; K.E. Duncan; J.M. Suflita.  2008.  Bioenergy production via microbial conversion of residual oil to natural gas.  Appl. Environ. Microbiol.  74: 3022-3029.
  
• Davidova, I. A., L. M. Gieg, K. E. Duncan, J.M. Suflita. 2007. Anaerobic phenanthrene mineralization by a carboxylating sulfate-reducing bacterial enrichment.  ISME J. 1: 436-442.
  
• Callaghan, A.V.; L. M. Gieg; K. G. Kropp; J. M. Suflita; L. Y. Young.  2006.  Comparison of mechanisms of alkane metabolism under sulfate-reducing conditions among two bacterial isolates and a bacterial consortium.  Appl. Environ. Microbiol. 72: 4274-4282.
  
• Gieg, L. M. and J.M. Suflita.  2005.  Metabolic Indicators of Anaerobic Hydrocarbon Biodegradation in Petroleum-Laden Environments.  In Petroleum Microbiology, Eds. B. Ollivier and M. Magot; ASM Press, Washington, D. C., pp. 337-356.   
  
• Davidova, I. A.; L. M. Gieg; M. Nanny; K. G. Kropp; J.M. Suflita. 2005. Stable isotopic studies of n-alkane  metabolism by  a sulfate-reducing bacterial enrichment.  Appl. Environ. Microbiol. 71: 8174-8182.
• Alumbaugh, R. E.; L. M. Gieg; J.A. Field. 2004. Determination of alkylbenzene metabolites in groundwater by solid-phase extraction and liquid chromatography-tandem mass spectrometry.  J. Chromatog. A 1042: 89-97.
• McInerney, M.J. and L. M. Gieg.  2004. An Overview of Anaerobic Metabolism.  In: Strict and Facultative Anaerobes:  Medical and Environmental Aspects, Eds. M. M. Nakano and P. Zuber; Horizon Bioscience, Norwich, U.K., pp. 27-65.
• Suflita, J.M.; I.A. Davidova; L. M. Gieg; M. Nanny; R.C. Prince. 2004. Anaerobic Hydrocarbon Biodegradation and the Prospects for Microbial Enhanced Energy Production.  In:  Petroleum Biotechnology:  Developments and Perspectives (Studies of Surface Science and Catalysis, Vol 151),  Eds. R. Vasquez-Duhalt amd R. Quintero-Ramirez, Elsevier Science Press, pp. 283-306.
• Rios-Hernandez, L.A.; L. M. Gieg; J. M. Suflita. 2003. Biodegradation of an alicyclic hydrocarbon by a sulfate-reducing enrichment from a gas condensate-contaminated aquifer.  Appl. Environ. Microbiol. 69: 434-443.
• Gieg, L. M. and J.M. Suflita. 2002. Detection of anaerobic metabolites of saturated and aromatic hydrocarbons in petroleum-contaminated aquifers. Environ. Sci. Technol. 36: 3755-3762.
  
• Elshahed, M.E.; L. M. Gieg*; M.J. McInerney; J.M. Suflita. 2001.  Signature metabolites attesting to the in situ attenuation of alkylbenzenes in anaerobic environments.  Environ. Sci. Technol. 35: 682-689 (*corresponding author).
  
• Gieg, L. M.; R.V. Kolhatkar; M.J. McInerney; R.S. Tanner; S.H. Harris; K.L. Sublette; J.M. Suflita. 1999.  Evidence for intrinsic bioremediation in a gas condensate-contaminated aquifer. Environ. Sci. Technol. 33: 2550-2560