Halonatronum saccharophilum gen. nov sp nov.: A new haloalkaliphilic bacterium of the order Haloanaerobiales from Lake Magadi

A new alkaliphilic and moderately halophilic chemoorganotrophic anaerobic b acterium (strain Z-7986), which is spore-forming, rod-shaped, and has a gra m-negative cell wall pattern, was isolated from the coastal lagoon mud of t he highly mineralized Lake Magadi (Kenya). The organism is an obligatorily carbonate- and sodium chloride-dependent motile peritrichously flagellated rod that grows within a 3-17% NaCl concentration range (with an optimum at 7-12% NaCl) and within a pH range of 7.7-10.3 (with an optimum at pH values of 8-8.5). It is a moderate thermophile with a broad temperature optimum a t 36-55 degreesC; maximum growth temperature is 60 degreesC. The bacterium catabolizes glucose, fructose, sucrose, maltose, starch, glycogen, N-acetyl -D-glucosamine, and, to a slight degree, peptone and yeast extract. Its ana bolism requires yeast extract or casamino acids. Glucose fermentation yield s formate, acetate, ethanol, H-2, and CO2. The bacterium is sulfide-toleran t and capable of the nonspecific reduction of S-0 to H2S. The G+C content o f the DNA is 34.4 mol %. The analysis of the 16S rRNA sequence revealed tha t strain Z-7986 belongs to the order Haloanaerobiales and represents a new genus in the family Halobacteroidaceae. We suggest the name Halonatronum sa ccharophilum gen. nov, sp. nov. The type strain of this species is Z-7986(T ) (= DSM13868, = Uniqem*211).