Haloanaerobium lacusroseus sp. nov., an Extremely Halophilic Fermentative Bacterium from the Sediments of a Hypersaline Lake

Abstract

A new extremely halophilic chemoorganotrophic bacterium (strain H200T [T = type strain]) was isolated from the hypersaline sediments of Retba Lake in Senegal. This organism was a sluggishly motile, rod-shaped, non-spore-forming, gram-negative, obligate anaerobe that grew optimally at 40°C in the presence of 180 to 200 g of NaCl per liter. The DNA base composition was 32 mol% guanine plus cytosine. The fermentation products from glucose were ethanol, acetate, H,, and CO,. Yeast extract was required for growth. The fermentable substrates included D-fructose, galactose, D-xylose, cellobiose, lactose, maltose, sucrose, starch, D-mannitol, glycerol, and Casamino Acids. On the basis of the results of a 16s rRNA sequence analysis, strain H200T was found to be related to Haloanaerobium species. The 16s rRNA sequence of strain H200T differed from the sequences of the three previously described Haloanaerobium species, and strain H200T also differed from these organisms in its NaCl range for growth (60 to 340 g/liter); strain H200T grew in the presence of the highest NaCl concentration recorded for any halophilic anaerobic organism, including the three previously described Haloanaerobium species. We propose that strain H200T (= DSM 10165) belongs to a new Haloanaerobium species, Haloanaerobium lacusroseus.Scientific interest in extremophilic anaerobic microorganisms has recently increased because of the possible biotechnological use of enzymes and molecules from such organisms (17). Among the extremophilic anaerobic bacteria, less attention has been paid to extreme halophiles (organisms that grow most rapidly in the presence of 200 to 300 g of NaCl per liter) than to hyperthermophiles.Hypersaline ecosystems (inland lakes, marine salterns) exhibit great variability in ionic composition, total salt concentration, and pH and are inhabited by aerobic and anaerobic microfloras (19). The strictly anaerobic halophiles that have been isolated from hypersaline ecosystems include sulfate-reducing bacteria, methanogenic bacteria, phototrophic bacteria, and fermentative bacteria (19, 21). Of the 14 species of fermentative halophilic anaerobes belonging to the family Haloanaerobiaceae that have been described (21, 23), only the following 3 are extreme halophiles that exhibit optimum growth in the presence of approximately 200 g of NaCl per liter but do not at more than 300 g of NaCl per liter: Halobacteroides lacunaris, an organism obtained from hypersaline Lake Chokrak on the Kerch Peninsula (33); Haloanaerobacter chitinovorans, an organism obtained from a southern California solar saltern (15); and Acetohalbbiurn arabaticum, an organism obtained from Lake Sivash (34).As very little attention has been paid to the extremely halophilic fermentative anaerobic bacteria, we initiated work to isolate such bacteria from hypersaline environments. In this paper we describe the isolation from the sediment of a hyper- saline lake of an extremely halo hilic chemoorganotrophic anaerobic bacterium, strain H200 (T = type strain), which grows in the ...

Microbial Diversity in Water and Sediment of Lake Chaka, an Athalassohaline Lake in Northwestern China

“…4B). These sequences were related (94 to 95% similarity) to Halocella cellulolsilytica (X89072) and Haloanaerobium lacurosei (L39787), two isolates from hypersaline lake sediments or lagoons (8,44). Halocella cellulolsilytica and Haloanaerobium lacurosei are obligate anaerobes with optimal growth at pH 7.0 and NaCl concentrations of 15% and 20%, (wt/vol), respectively.…”

Extremely Halophilic Bacteria in Crystallizer Ponds from Solar Salterns

“…One is Halorhodospira halophila (formerly Ectothiorhodospira halophila), a halophilic phototrophic bacterium isolated from soda lakes (10), which grows optimally in an environment around 25% NaCl. The second is Haloanaerobium lacusroseus (8), an anerobic bacterium isolated from sediments of a hypersaline lake. There is also one actinomycete, Actinopolyspora halophila, able to grow in saturated NaCl that was first isolated as a contaminant of culture medium containing 25% NaCl (11).…”

Haloanaerobium fermentans sp. nov., a strictly anaerobic, fermentative halophile isolated from fermented puffer fish ovaries.

“…In addition, isolate R-9 T and Haloanaerobium praevalens can be differentiated by motility. Haloanaerobium lacusrosei (Cayol et al, 1995) is an extremely halophilic bacterium that grows optimally in 18-20 % (w\v) NaCl. Therefore, isolate R-9 T could be differentiated from Haloanaerobium lacusrosei on the basis of optimal salt concentration, since optimal growth of isolate R-9 T was observed in 10 % (w\v) NaCl, as well as some differences of substrate profiles, such as the ability to ferment glycerol and starch.…”

“…Eight species of this genus have been described previously. They have been isolated from various hypersaline environments : the Great Salt Lake (Zeikus et al, 1983 ;Tsai et al, 1995), Sivash Lake (Zhilina et al, 1992), Retba Lake (Cayol et al, 1994(Cayol et al, , 1995, gasbearing sandstones and brine waters (Rengpipat et al, 1988), petroleum reservoir fluid (Bhupathiraju et al, 1994(Bhupathiraju et al, , 1999 and oil-injection water (Ravot et al, 1997).…”