title: Biodegradation of methyl tert-butyl ether by cold-adapted mixed and pure bacterial cultures.
abstract: An aerobic mixed bacterial culture (CL-EMC-1) capable of utilizing methyl tert-butyl ether (MTBE) as the sole source of carbon and energy with a growth temperature range of 3 to 30 degrees C and optimum of 18 to 22 degrees C was enriched from activated sludge. Transient accumulation of tert-butanol (TBA) occurred during utilization of MTBE at temperatures from 3 degrees C to 14 degrees C, but TBA did not accumulate above 18 degrees C. The culture utilized MTBE at a concentration of up to 1.5 g l(-1) and TBA of up to 7 g l(-1). The culture grew on MTBE at a pH range of 5 to 9, with an optimum pH of 6.5 to 7.1. The specific growth rate of the CL-EMC-1 culture on 0.1 g l(-1) of MTBE at 22 degrees C and pH 7.1 was 0.012 h(-1), and the growth yield was 0.64 g (dry weight) g(-1). A new MTBE-utilizing bacterium, Variovorax paradoxus strain CL-8, isolated from the mixed culture utilized MTBE, TBA, 2-hydroxy isobutyrate, lactate, methacrylate, and acetate as sole sources of carbon and energy but not 2-propanol, acetone, methanol, formaldehyde, or formate. Two other isolates, Hyphomicrobium facilis strain CL-2 and Methylobacterium extorquens strain CL-4, isolated from the mixed culture were able to grow on C(1) compounds. The combined consortium could thus utilize all of the carbon of MTBE.
authors.affiliation: ARMI, Arctic Microbiology Research Consortium, Finnish Forest Research Institute, Rovaniemi Research Station, Box 16, 96301 Rovaniemi, Finland. gennadi.zaitsev@pp.inet.fi
authors.forename: G M
authors.initials: GM
authors.lastname: Zaitsev
authors.forename: J S
authors.initials: JS
authors.lastname: Uotila
authors.forename: M M
authors.initials: MM
authors.lastname: Häggblom
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003080:Cold Temperature; D042621:Comamonadaceae / Q000378:metabolism; D020582:Hyphomicrobium / Q000378:metabolism; D008738:Methyl Ethers / Q000378:metabolism*; D020601:Methylobacterium extorquens / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*
chemical_list: D008738:Methyl Ethers; D012722:Sewage; C043243:methyl tert-butyl ether