Haloanaerobacter salinarius sp. nov., a novel halophilic fermentative bacterium that reduces glycine-betaine to trimethylamine with hydrogen or serine as electron donors; emendation of the genus Haloanaerobacter

A novel halophilic fermentative bacterium has been isolated from the black sediment below a gypsum crust and a microbial mat in hypersaline ponds of M editerranean salterns, Morphologically, physiologically and genetically thi s organism belongs to the genus Haloanaerobacter, Haloanaerobacter strain S G 3903(T) (T = type strain) is composed of non-sporulating long flexible ro ds with peritrichous flagella, able to grow in the salinity range of 5-30% NaCl, with an optimum at 14-15%. The strain grows by fermenting carbohydrat es or by using the Stickland reaction with either serine or H-2 as electron donors and glycine-betaine as acceptor, which is reduced to trimethylamine . The two Species described so far in the genus Haloanaerobacter are not ca pable of Stickland reaction with glycine-betaine + serine; however, Haloana erobacter chitinovorans can use glycine-betaine with H-2 as electron donor. Strain SC 3903(T) thus represents the first described strain in the genus Haloanaerobacter capable of the Stickland reaction with two amino acids. Al though strain SC 3903(T) showed 67% DNA-DNA relatedness to H. chitinovorans , it is physiologically sufficiently different from the two described speci es to be considered as a new species which has been named Haloanaerobacter salinarius sp, nov.