Alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor

International Journal of Systematic and Evolutionary Microbiology
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Abstract

A facultative chemoautotrophic bacterium, strain MLHE-1, was isolated from Mono Lake, an alkaline hypersaline soda lake in California, USA. Cells of strain MLHE-1 were Gram-negative, short motile rods that grew with inorganic electron donors (arsenite, hydrogen, sulfide or thiosulfate) coupled with the reduction of nitrate to nitrite. No aerobic growth was attained with arsenite or sulfide, but hydrogen sustained both aerobic and anaerobic growth. No growth occurred when nitrite or nitrous oxide was substituted for nitrate. Heterotrophic growth was observed under aerobic and anaerobic (nitrate) conditions. Cells of strain MLHE-1 could oxidize but not grow on CO, while CH neither supported growth nor was it oxidized. When grown chemoautotrophically, strain MLHE-1 assimilated inorganic carbon via the Calvin–Benson–Bassham reductive pentose phosphate pathway, with the activity of ribulose 1,5-bisphosphate carboxylase (RuBisCO) functioning optimally at 0.1 M NaCl and at pH 7.3. Strain MLHE-1 grew over broad ranges of pH (7.3–10.0; optimum, 9.3), salinity (15–190 g l; optimum 30 g l) and temperature (13–40 °C; optimum, 30 °C). Phylogenetic analysis of 16S rRNA gene sequences placed strain MLHE-1 in the class (family ) and most closely related to  (98.5 %) and  (98.6 %), although none of these three haloalkaliphilic micro-organisms were capable of photoautotrophic growth and only strain MLHE-1 was able to oxidize As(III). On the basis of physiological characteristics and DNA–DNA hybridization data, it is suggested that strain MLHE-1 represents a novel species within the genus  for which the name  is proposed. The type strain is MLHE-1 (=DSM 17681=ATCC BAA-1101). Aspects of the annotated full genome of  are discussed in the light of its physiology.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Alkalilimnicola ehrlichii sp. nov., a novel, arsenite-oxidizing haloalkaliphilic gammaproteobacterium capable of chemoautotrophic or heterotrophic growth with nitrate or oxygen as the electron acceptor
Series title International Journal of Systematic and Evolutionary Microbiology
DOI 10.1099/ijs.0.64576-0
Volume 57
Issue 504
Year Published 2007
Language English
Publisher International Union of Microbiological Societies
Contributing office(s) Toxic Substances Hydrology Program
Description 9 p.
First page 504
Last page 512
Country United States
State California
Other Geospatial Mono Lake