Michael J. McInerney

George Lynn Cross Research Professor
George Lynn Cross Endowed Professor
Applied Microbial Physiology

Metabolic reconstruction of the
metabolism of Syntrophomonas wolfei
Microbial consortia are essential for the conversion of complex polymeric materials into biofuels such as methane, hydrogen, or alcohols. We are studying the physiology of microorganisms involved in biofuel production and the molecular events by which model microbial consortia respond to environmental change and regulate the flow of carbon and electrons.
 

Bacterial Syntrophy

Syntrophy is an essential interaction in methane production, which involves the interaction between hydrogen- and formate-producing microbes with hydrogen- and formate-using partners. The Gibbs free energy changes involved in syntrophic metabolism are very low, close to the minimum free energy change needed to sustain microbial growth. A distinctive feature of syntrophic metabolism is the need for reverse electron transfer to produce of hydrogen or formate from electrons generated in the oxidation fatty and aromatic acids. We are using a combination of proteomic, gene expression, and biochemical approaches to (1) detect the membrane complexes involved in reverse electron transfer, (2) conduct gene expression and operon analyses to identify if key gene systems that are induced when reverse electron transfer is needed, and (3), characterize biochemically the membrane complexes involved in reverse electron transfer.
Benzoate degradation by a model syntrophic consortium. Dashed blues lines indicate additional sources of cell carbon for the methanogens
This is a collaborative effort with Professor Robert P. Gunsalus (http://www.mimg.ucla.edu/faculty/gunsalus/) and Professors Rachel and Joseph Loo at UCLA (http://www.biochemistry.ucla.edu/biochem/Faculty/Loo/). Our work will allow us to understand an essential and poorly characterized process critical for carbon cycling on the planet and will demonstrate how bacteria operate at free energy changes close to equilibrium.
 

Biohydrogen Production

We are also studying biohydrogen production from renewable resources by a new microbial species called Anaerobaculum hydrogeniformans strain OS1. A. hydrogeniformans produces over 3 mol H2 per mole glucose at H2 gas phase concentrations up to 17%. We will delineate the enzymes systems involved in H2 production from carbohydrate and amino acids by A. hydrogeniformans strain OS1 and the metabolic and regulatory networks that allow efficient H2 production from glucose and amino acids. To accomplish our objectives, we are using a combination of classical biochemical approaches coupled with high-throughput technologies including genome-wide expression profiling and proteomics. Our work will provide a “systems level” understanding of the metabolic, regulatory, and physiological networks operative in hydrogen-based microbial communities. It will also allow improved assessment and predictions regarding microbially assisted, cellulosic bioconversions.

Selected Recent Publications
  1. J. R. Sieber, D. R. Sims, C. Han, E. Kim, A. Lykidis, A. L. Lapidus, E. McDonnald, L. Rohlin, D. E. Culley, R. P. Gunsalus, and M. J. McInerney. 2010. The genome of Syntrophomonas wolfei: new insights into syntrophic metabolism and biohydrogen production. Environ. Microbiol. 12(9): 2289-2301.
  2. H. Mouttaki, M. Nanny, and M. J. McInerney. 2009. The metabolism of hydroxylated and fluorinated benzoates by Syntrophus aciditrophicus and the detection of a fluorinated diene metabolite. Appl. Environ. Microbiol. 75: 998-1004.
  3. X Li, Q. Luo, N. Q. Wofford, K. L. Keller, M. M. McInerney, J. Wall and L. R. Krumholz. 2009. A molybdopterin oxidoreductase is involved in H2 oxidation in Desulfovibrio desulfuricans G20. J. Bacteriol. 191: 2675-2682.
  4. M. J. McInerney, J. R. Sieber, and R. P. Gunsalus. 2009. Syntrophy in anaerobic global carbon cycles. Current Opinion in Biotechnology 20: 623–632. (DOI 10.1016/j.copbio.2009.10.001) (Illustration made journal cover)
  5. Youssef, N., M. S. Elshahed, and M. J. McInerney. 2009. Microbial processes in oil fields: culprits, problems and opportunities. Adv. Appl. Microbiol. 66: 141-251.
  6. K. Kuntze, Y. Shinoda, H. Mouttaki, M. J. McInerney, C. Vogt, H.-H. Richnow and M. Boll. 2008. 6-Oxocyclohexene-1-carbonyl-CoA hydrolases from obligately anaerobic bacteria: characterization and identification of its gene and development of a functional marker for aromatic compounds-degrading anaerobes. Environ. Microbiol. 10: 1547-1556.
  7. T. Nguyen, N. Youssef, M. J. McInerney, and D. Sabatini, D. 2008. Rhamnolipid biosurfactant mixtures for environmental remediation. Water Res. 42: 1735-1743.
  8. H. Mouttaki, M. Nanny, and M. J. McInerney. 2008. Use of benzoate as an electron acceptor by Syntrophus aciditrophicus grown in pure culture with crotonate. Environ. Microbiol. 10: 3265-3274.
  9. H. Mouttaki, M. A. Nanny, and M. J. McInerney. 2007. Cyclohexane carboxylate and benzoate formation from crotonate in Syntrophus aciditrophicus. Appl. Environ. Microbiol. 73: 930-938.
  10. F. Peters, Y. Shinoda, M. J. McInerney, and M. Boll. 2007. Cyclohex-1,5-diene-1-carbonyl-coenzyme A hydratases of Geobacter metallireducens and Syntrophus aciditrophicus: evidence for a common benzoyl-CoA pathway in facultative and obligate anaerobes. J. Bacteriol. 189: 1055-1060
  11. N. Youssef, D. R. Simpson, K. E. Duncan, M. J. McInerney, M. Folmsbee, T. Fincher, and R. M. Knapp. 2007. In-situ biosurfactant production by injected Bacillus strains in a limestone petroleum reservoir. Appl. Environ. Microbiol. 73:1239-1247.

For more information about this program, contact the Department or Dr. Mike McInerney.

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