title: Acetonitrile degradation under haloalkaline conditions by Natronocella acetinitrilica gen. nov., sp. nov.
abstract: Nitriles are important environmental compounds, both as natural products and industrial pollutants. Until now, there have been no data on the possibility of microbial nitrile degradation at high pH/salt conditions. Acetonitrile (CH(3)C(triple bond)N) is the simplest organic nitrile. Here, evidence is provided of microbial utilization of acetonitrile as a carbon, energy and nitrogen source at extremely high pH and moderate salinity. Positive enrichment cultures with acetonitrile at pH 10 and salt content equivalent to 0.6 M total Na(+) were obtained from mixed sediment samples from soda lakes, but not from soda soils. Purification of these cultures resulted in the isolation of two bacterial strains capable of growth with acetonitrile as sole carbon, energy and nitrogen source under haloalkaline conditions. Apart from acetonitrile, the bacteria also grew with propionitrile. Nitrile hydrolysis to acetamide was identified as the rate-limiting step of acetonitrile degradation via the nitrile hydratase/amidase pathway. The new bacteria belonged to moderately salt-tolerant obligate alkaliphiles with optimum growth at pH 10 and 0.5 M total Na(+). The cells were yellow-coloured due to a high concentration of carotenoids dominated by zeaxanthin. Phylogenetic analysis placed the isolates into a new lineage within the family Ectothiorhodospiraceae in the Gammaproteobacteria. On the basis of unique phenotypic properties and their separate phylogenetic position, the new bacteria are placed into a new genus and species for which the name Natronocella acetinitrilica gen. nov., sp. nov is proposed.
authors: Environmental Biotechnology, Faculty of Applied Sciences, 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: Biocatalysis and Organic Chemistry, Faculty of Applied Sciences, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors: Sander
authors: S
authors: van Pelt
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: Biological Laboratory, Nippon Medical School, Kosugi, Nakahara, Kawasaki 211-0063, Japan.
authors: Shinichi
authors: S
authors: Takaichi
authors: Environmental Biotechnology, Faculty of Applied Sciences, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands.
authors: Gerard
authors: G
authors: Muyzer
mesh_terms: D000097:Acetonitriles / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005618:Fresh Water / Q000382:microbiology*; D020563:Gammaproteobacteria / Q000145:classification* / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D012965:Sodium Chloride / Q000378:metabolism
chemical_list: D000097:Acetonitriles; D012965:Sodium Chloride; C032159:acetonitrile