title: Aerobic carboxydotrophy under extremely haloalkaline conditions in Alkalispirillum/Alkalilimnicola strains isolated from soda lakes.
abstract: Aerobic enrichments from soda lake sediments with CO as the only substrate resulted in the isolation of five bacterial strains capable of autotrophic growth with CO at extremely high pH and salinity. The strains belonged to the Alkalispirillum/Alkalilimnicola cluster in the Gammaproteobacteria, where the ability to oxidize CO, but not growth with CO, has been demonstrated previously. The growth with CO was possible only at an oxygen concentration below 5 % and CO concentration below 20 % in the gas phase. The isolates were also capable of growth with formate but not with H(2). The carboxydotrophic growth occurred within a narrow pH range from 8 to 10.5 (optimum at 9.5) and a broad salt concentration from 0.3 to 3.5 M total Na(+) (optimum at 1.0 M). Cells grown on CO had high respiration activity with CO and formate, while the cells grown on formate actively oxidized formate alone. In CO-grown cells, CO-dehydrogenase (CODH) activity was detectable both in soluble and membrane fractions, while the NAD-independent formate dehydrogenase (FDH) resided solely in membranes. The results of total protein profiling and the failure to detect CODH with conventional primers for the coxL gene indicated that the CO-oxidizing enzyme in haloalkaliphilic isolates might differ from the classical aerobic CODH complex. A single cbbL gene encoding the RuBisCO large subunit was detected in all strains, suggesting the presence of the Calvin cycle of inorganic carbon fixation. Overall, these results demonstrated the possibility of aerobic carboxydotrophy under extremely haloalkaline conditions.
authors: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.|Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
authors: Dimitry Yu
authors: DY
authors: Sorokin
authors: Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
authors: Tatjana P
authors: TP
authors: Tourova
authors: Faculty of Biology, Department of Microbiology, Moscow State University, Moscow, Russia.
authors: Olga L
authors: OL
authors: Kovaleva
authors: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors: J Gijs
authors: JG
authors: Kuenen
authors: Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors: Gerard
authors: G
authors: Muyzer
mesh_terms: D002248:Carbon Monoxide / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D042001:Ectothiorhodospiraceae / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification* / Q000378:metabolism; D005561:Formates / Q000378:metabolism; D019015:Geologic Sediments / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics; D054712:Salinity; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D005561:Formates; D012336:RNA, Ribosomal, 16S; C030544:formic acid; D002248:Carbon Monoxide; D012273:Ribulose-Bisphosphate Carboxylase