One of the goals of the SB 521 research was to develop economically feasible ways to remove MTBE from water.  Different treatment technologies have advantages and disadvantages in a given situation: air stripping with vapor treatment may be difficult and costly, adsorbents need to be disposed of in hazardous waste sites or regenerated and photo- or chemical oxidation may create by-products.

Biodegradation of MTBE has been under investigation at UCD over the past decade.  Researchers from the Department of Civil/Environmental Engineering determined biodegradation rates and operating parameters for a mixed culture microbial consortium recovered from a biofilter (used for gas phase treatment of vapors) at the Joint Water Pollution Control Plant in Carson, CA. Graduate student researchers were able to culture the microbial consortium and determined conditions under which it thrived. Subsequently they developed lab and pilot scale biofilters, a trickling filter with an activated carbon medium and a fluidized sand bed reactor (for contaminated water treatment). The latter effort was a collaboration with Environmental Resolutions Inc. which has commercialized the technology for ex situ remediation of MTBE and tertiary butyl alcohol (TBA) a degradation byproduct of MTBE. There have now been over 30 successful installations at pump-and-treat sites throughout California and more recently the East Coast. Researchers in the Soil Science branch of the Department of Land, Air, and Water Resources have characterized the MTBE/TBA-degrading species, PM-1, present in the original microbial consortium, developed methods to track PM-1 in field applications, have participated in in situ bioaugmentation tests at field sites at Port Hueneme and Vandenberg AFB, and in collaboration with Lawrence Livermore National Laboratory, have recently determined the entire genome of PM-1. They have also licensed the PM-1 organism to the Regenesis corporation to make it commercially available for bioaugmentation when needed. The new official scientific name of the organism is Methylobium petroleophilum PM1.

A chronological list of references to papers published by the UCD bioremediation researchers appears below:

Eweis, J.; Chang, D.P.Y.; Schroeder, E.D.; Scow, K.M.; Morton, R.L.; Caballero, R.C. (1997). "Meeting the challenge of MTBE biodegradation." In Proceedings of the 90th Annual Meeting and Exhibition of the Air & Waste Management Association; Toronto, Canada.

Eweis, J.B.; Schroeder, E.D.; Chang, D.P.Y.; Scow, K.M. (1998). "Biodegradation of MTBE in a pilot-scale biofilter." In Natural Attenuation: Chlorinated and Recalcitrant Compounds; Wickramanayake, G. B., Hinchee, R. E., Eds.; Battelle Press: Columbus, OH,; pp 341-346.

Hanson, J.R.; Ackerman, C.E.; Scow, K.M. (1999). "Biodegradation of Methyl tert Butyl Ether by a Bacterial Pure Culture." Applied & Environmental Microbiology, 65(11): 4788–4792.

Chang, D.P.Y.; Schroeder, E.D.; Scow, K.M.; Converse, B.M.; Scarano, J.; Watanabe, N.; Romstad, K. (2000) "Experience with Laboratory and Field-Scale Ex Situ Biodegradation of MTBE." In: Proceedings of the Environmental Protection Agency/American Petroleum Institute MTBE Biodegradation Workshop, Cincinnati, Feb. 1-3, 2000.

Deeb, R.A.; Nishino, S.; Spain, J.; Hu, H.Y.; Scow, K.M.; Alvarez-Cohen, L. (2000a). "MTBE and benzene biodegradation by PM1 via two independent monooxygenase-initiated pathways." Abstracts of Papers American Chemical Society 219:ENVR 228.

Deeb, R.A.; Scow, K.M.; Alvarez-Cohen, L. (2000b). "Aerobic MTBE biodegradation: an examination of past studies, current challenges and future research directions." Biodegradation, 11: 171–186.

MacKay, D.M.; Durrant, W.R.; Scow K.M.; Smith, A.; Einarson, M.; Fowler, B. (2000) "In Situ Treatment of MTBE by Biostimulation of Native Aerobic Microorganisms." In: Proceedings of the Environmental Protection Agency/American Petroleum Institute MTBE Biodegradation Workshop, Cincinnati, Feb. 1-3, 2000.

Converse, B.M.; Schroeder, E.D.; Chang, D.P.Y. (2000). "Liquid Phase Biodegradation of Methyl Tertiary Butyl Ether Using a Granular Activated Carbon Trickling Filter in the Field." Paper WR-2h, CD-ROM Proceedings of the Air & Waste Management 93rd Annual Conference & Exhibition.

Bruns, M.A.; Hanson, J.R.; Mefford, J.; Scow, K.M. (2001). "Isolate PM1 populations are dominant and novel methyl tert-butyl ether-degrading bacteria in compost biofilter enrichments." Environmental Microbiology, 3(3): 220-225.

Deeb, R.A.; Hu, H.-Y.; Hanson, J.R .; Scow, K. M .; Alvarez-Cohen, L. (2001). "Substrate Interactions in BTEX and MTBE Mixtures by an MTBE-Degrading Isolate." Environ. Sci. Technol., 35: 312-317.

Hristova, K.R.; Lutenegger, C.M.; Scow, K.M. (2001). "Detection and Quantification of Methyl tert-Butyl Ether-Degrading Strain PM1 by Real-Time TaqMan PCR." Applied & Environmental Microbiology, 67(11): 5154–5160.

Gray, J.R.; Lacrampe-Couloume, G.; Gandhi, D.; Scow, K.M.; Wilson, R.D.; Mackay, D.M.; Lollar, B.S. (2002). "Carbon and Hydrogen Isotopic Fractionation during Biodegradation of Methyl tert-Butyl Ether." Environ. Sci. Technol., 36: 1931-1938.

Naas, C.; Wilson, R.; Mackay, D.M.; Scow, K.M. (2002) "Investigation of spatial distribution of native aerobic MTBE degrading microorganisms: preliminary results." Contam. Soil, Sediment and Water (July/August):76-79.

Stavnes, S.A.; Fleischman, J.J.; Goetz, J.; Kemper, M.; Roulier, M.; Hristova, K.R.; Scow, K.M.; Knutson, K.; Mahaffey, W.R.; Slomczynski, D.J.; Davis-Hoover, W. (2002) "MTBE Bioremediation with BioNetsTM Containing Isolite, PM1, Solid Oxygen Source (SOS) or air." In: A. R. Gavaskar and A.S.C. Chen (Eds.), Remediation of Chlorinated and Recalcitrant Compounds. Proceedings of the Third International Conference of Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2002), Part B, Paper 2B-66. Battelle Press, Columbus, OH.

Wilson, R.D.; Mackay, D.M.; Scow, K.M . (2002). "In Situ MTBE Biodegradation Supported by Diffusive Oxygen Release." Environ. Sci. Technol. 36: 190-199.

Davis-Hoover, W.J.; Stavnes, S.A.; Fleischman, J.J.; Hunt, S.C.; Goetz, J.; Keper, M.; Roulier, M.; Hristova, K.R.; Scow, K.M.; Knutson, K.; Mahaffee, W.; Slomczynski, D.J. (2003). "BTEX, MTBE Bioremediation Containing PM1, SOS or Air." Paper E-25. In: V.S. Magar and M.E. Kelley (Eds.), In Situ and On-Site Bioremediation—2003. Proceedings of the Seventh International In Situ and On-Site Bioremediation Symposium (Orlando, FL; June 2003). Battelle Press, Columbus, OH.

Hristova, K.R.; Gerbreyesus. B.; Mackay, D.; Scow, K.M. (2003). "MTBE-Degrading Bacterium, Strain PM1, Is Naturally Occuring in MTBE Contaminated Aquifers." Appl. Environ. Microbiol., 69(5): 2616-2623.

Davis-Hoover, W.J.; Stavnes, S.A.; Fleischman, J.J.; Hristova, K.R.; Scow, K.M.; Goetz, J.; Kemper M.; Knutson, K.; Mahaffey, W.R.; Slomczynski, D.J.; Feldhake, D. (2004). "Microbial Analysis of MTBE, BTEX Bioremediation: BionetsTM Containing PM1, SOS, Isolite." Battelle Press, Columbus, OH.

Feris, K.P.; Hristova, K.; Gebreyesus, B.; Mackay, D.; Scow, K.M. (2004). "A Shallow BTEX and MTBE Contaminated Aquifer Supports a Diverse Microbial Community." Microbial Ecology, 48: 589–600.

Smith, A.E.; Hristova, K.; Wood, I.; Mackay, D.M.; Lory, E. Lorenzana, D.; Scow, K.M. (2005). "Comparison of Biostimulation versus Bioaugmentation with Bacterial Strain PM1 for Treatment of Groundwater Contaminated with Methyl Tertiary Butyl Ether (MTBE)." Environmental Health Perspectives, 113(3): 317-322.

Nakatsu, C.H.; Hristova, K.R.; Hanada, S.; Meng, X.-Y.; Hanson, J.R.; Scow, K.M.; Kamagata, Y. (2006). "Methylobium petroleophilum PM1 gen. nov., sp. nov., a new methyl tert-butyl ether (MTBE) degrading methylotroph belonging to the beta-subclass of the Proteobacteria." Int. J. Sys. Evol. Microbiol. 56: 983-989.

To read a paper about the initial discovery of an MTBE-degrading consortium presented at the Air & Waste Management Association's 90^th Annual Meeting & Exhibition, June 8-13, 1997, Toronto, Ontario, Canada, click here.

To read a paper presented at The First International Conference on Remediation of Chlorinated and Recalcitrant Compounds, sponsored by Batelle, May 18-21, 1998, Monterey, California (published as J.B. Eweis, E.D. Schroeder, D.P.Y. Chang, K.M. Scow, "Biodegradation of MTBE in a Pilot-Scale Biofilter", from G.B. Wickramanayake and R.E. Hinchee (Editors), Natural Attenuation:  Chlorinated and Recalcitrant Compounds, Battelle Press, Columbus, Ohio, pages 341-346, 1998.) click here.

To read a paper presented at the National Ground Water Association Conference, (The Southwest Focused Ground Water Conference Discussing the Issue of MTBE and Perchlorate in Ground Water, June 3-4, 1998, Anaheim, California), click here.

To read an extended abstract of a presentation by Chang, D.P.Y.; Schroeder, E.D.; Scow, K.M.; Converse, B.M.; Scarano, J.; Watanabe, N.; Romstad, K. entitled "Experience with Laboratory and Field-Scale Ex Situ Biodegradation of MTBE." In: Proceedings of the Environmental Protection Agency/American Petroleum Institute MTBE Biodegradation Workshop, Cincinnati, Feb. 1-3, 2000 click here.

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