Bacillus arsenicoselenatis, sp. nov., and Bacillus selenitireducens, sp. nov.: two haloalkaliphiles from Mono Lake, California that respire oxyanions of selenium and arsenic

Two gram-positive anaerobic bacteria (strains E1H and MLS10) were isolated from the anoxic muds of Mono Lake, California, an alkaline, hypersaline, arsenic-rich water body. Both grew by dissimilatory reduction of As(V) to As(III) with the concomitant oxidation of lactate to acetate plus CO₂. Bacillus arsenicoselenatis (strain E1H) is a spore-forming rod that also grew by dissimilatory reduction of Se(VI) to Se(IV). Bacillus selenitireducens (strain MLS10) is a short, non-spore-forming rod that grew by dissimilatory reduction of Se(IV) to Se(0). When the two isolates were cocultured, a complete reduction of Se(VI) to Se(0) was achieved. Both isolates are alkaliphiles and had optimal specific growth rates in the pH range of 8.5–10. Strain E1H had a salinity optimum at 60 g l^–1 NaCl, while strain MLS10 had optimal growth at lower salinities (24–60 g l^–1 NaCl). Both strains have limited abilities to grow with electron donors and acceptors other than those given above. Strain MLS10 demonstrated weak growth as a microaerophile and was also capable of fermentative growth on glucose, while strain E1H is a strict anaerobe. Comparative 16S rRNA gene sequence analysis placed the two isolates with other Bacillus spp. in the low G+C gram-positive group of bacteria. Received: 21 May 1998 / Accepted: 31 August 1998     

Ferribacterium limneticum, gen. nov., sp. nov., an Fe(III)-reducing microorganism isolated from mining-impacted freshwater lake sediments

A dissimilatory Fe(III)-reducing bacterium was isolated from mining-impacted lake sediments and designated strain CdA-1. The strain was isolated from a 4-month enrichment culture with acetate and Fe(III)-oxyhydroxide. Strain CdA-1 is a motile, obligately anaerobic rod, capable of coupling the oxidation of acetate and other organic acids to the reduction of ferric iron. Fe(III) reduction was not observed using methanol, ethanol, isopropanol, propionate, succinate, fumarate, H₂, citrate, glucose, or phenol as potential electron donors. With acetate as an electron donor, strain CdA-1 also grew by reducing nitrate or fumarate. Growth was not observed with acetate as electron donor and O₂, sulfoxyanions, nitrite, trimethylamine N-oxide, Mn(IV), As(V), or Se(VI) as potential terminal electron acceptors. Comparative 16 S rRNA gene sequence analyses show strain CdA-1 to be most closely related (93.6% sequence similarity) to Rhodocyclus tenuis. However, R. tenuis did not grow heterotrophically by Fe(III) reduction, nor did strain CdA-1 grow photrophically. We propose that strain CdA-1 represents a new genus and species, Ferribacterium limneticum. Strain CdA-1 represents the first dissimilatory Fe(III) reducer in the β subclass of Proteobacteria, as well as the first Fe(III) reducer isolated from mine wastes. Received: 14 July 1998 / Accepted: 14 December 1998     

Natroniella acetigena gen. nov. sp. nov., an Extremely Haloalkaliphilic,Homoacetic Bacterium: A New Member of Haloanaerobiales

A new extremely haloalkaliphilic, chemoorganotrophic, homoacetogenic bacterium strain Z-7937^T(T-type strain) was isolated from the bottom mud of the soda-depositing Lake Magadi, Kenya. It is an obligately anaerobic, motile, Gram-negative, spore-forming rod growing in the pH range pH 8.1 to 10.7 and optimally in the range pH 9.7 to 10.0 under conditions of high alkalinity caused by saturation with trona. It has an obligate requirement for sodium carbonate and chloride ions. The optimum salt concentration for growth is in the range 12–15% wt/vol, and growth occurs within the range from 10% to 26%. Strain Z-7937^T is a mesophile with an optimal temperature for growth of 37°C, and a maximum of 42°C. The G + C content of strain Z-7937^T is 31.9 mol%. A limited number of compounds are utilized, including lactate, ethanol, pyruvate, glutamate, and propanol. Acetate is the main end product. 16S rDNA sequence analysis shows strain Z-7937^T to be a member of the order Haloanaerobiales and to represent a new branch within the family Halobacteroidaceae. On the basis of its novel physiology and phylogenetic position, we propose strain Z-7937 as a new species of a new genus, Natroniella acetigena gen. nov. sp. nov. The type strain is Z-7937^T (= DSM 9952).     

Natronoincola histidinovorans gen. nov., sp. nov., a New Alkaliphilic Acetogenic Anaerobe

Two strains, asporogenous Z-7940 and sporogenous Z-7939, of a moderately haloalkaliphilic, obligately anaerobic, fermentative bacteria, motile, with Gram-positive cell wall structure, were isolated from soda deposits in Lake Magadi, Kenya. Both strains are mesophilic and utilize only two amino acids, histidine and glutamate, with formation of acetate and ammonium as the main end products. Strain Z-7939 in addition is able to utilize pyruvate. DNA-DNA homology between strains Z-7940 and Z-7939 was 94%, indicating that in spite of phenotypic differences they belong to the same species. They are true alkaliphiles with a pH range for growth of the type strain Z-7940 from pH 8.0 to pH 10.5, optimum at pH 9.4. Both strains obligately depend on sodium and bicarbonate ions. The optimum salt concentration for growth of the type strain is 8–10% wt/vol and the range from 4% to 16%. The G+C content of strain Z-7940 is 31.9 mol% and the strain Z-7939 is 32.3 mol%. Analysis of 16S rDNA sequence of the type strain shows it to belong to cluster XI of the low G+C Gram-positive bacteria. On the basis of its distinct phylogenetic position and physiological properties, we propose a new genus and new species Natronoincola histidinovorans for these strains. The type strain is Z-7940 (=DSM 11416). Received: 5 March 1998 / Accepted: 3 April 1998     

Description of the novel perchlorate-reducing bacteria Dechlorobacter hydrogenophilus gen. nov., sp. nov. and Propionivibrio militaris, sp. nov.

Novel dissimilatory perchlorate-reducing bacteria (DPRB) were isolated from enrichments conducted under conditions different from those of all previously described DPRB. Strain LT-1^T was enriched using medium buffered at pH 6.6 with 2-(N-morpholino)ethanesulfonic acid (MES) and had only 95% 16S rRNA gene identity with its closest relative, Azonexus caeni. Strain MP^T was enriched in the cathodic chamber of a perchlorate-reducing bioelectrical reactor (BER) and together with an additional strain, CR (99% 16S rRNA gene identity), had 97% 16S rRNA gene identity with Propionivibrio limicola. The use of perchlorate and other electron acceptors distinguished strains MP^T and CR from P. limicola physiologically. Strain LT-1^T had differences in electron donor utilization and optimum growth temperatures from A. caeni. Strains LT-1^T and MP^T are the first DPRB to be described in the Betaproteobacteria outside of the Dechloromonas and Azospira genera. On the basis of phylogenetic and physiological features, strain LT-1^T represents a novel genus in the Rhodocyclaceae; strain MP^T represents a novel species within the genus Propionivibrio. The names Dechlorobacter hydrogenophilus gen. nov., sp. nov and Propionivibrio militaris sp. nov. are proposed.     

Thermococcus waiotapuensis sp. nov., an extremely thermophilic archaeon isolated from a freshwater hot spring

An extremely thermophilic, sulfur-dependent archaeon, strain WT1, was isolated from a freshwater hot spring in the Lake Taupo area of North Island, New Zealand. The cells are flagellated, strictly anaerobic cocci that grow optimally at 85 °C and 5.4 g NaCl l^–1. The strain grows heterotrophically on complex proteinaceous substrates or on appropriate salts plus amino acid mixtures and is also able to utilize maltose, starch, and pyruvate. Elemental sulfur could be replaced by cystine or thioglycollate. The range of temperatures allowing growth is from 60 to 90 °C; the pH supporting growth ranges from 5 to 8 (optimum, pH 7). Strain WT1 grew in a defined medium containing amino acids as the sole carbon and energy sources. The required amino acids were: Arg, His, Ile, Leu, Phe, Ser, Thr, Trp, Tyr, and Val. Strain WT1 showed sensitivity to rifampicin. DNA G+C content was 50.4 mol%. Phylogenetic analysis of the sequence encoding the 16S rRNA gene indicated that this isolate is a member of the Thermococcales. DNA/DNA hybridization studies revealed no similarity to several species of Thermococcus and Pyrococcus, with the exception of Thermococcus zilligii. Based on the reported results, we propose strain WT1 as a new species to be named Thermococcus waiotapuensis sp. nov. Received: 5 January 1999 / Accepted: 19 May 1999     

<Emphasis Type="Italic">Tindallia californiensis</Emphasis> sp. nov., a new anaerobic,haloalkaliphilic, spore-forming acetogen isolated from Mono Lake in California

A novel extremely haloalkaliphilic, strictly anaerobic, acetogenic bacterium strain APO was isolated from sediments of the athalassic, meromictic, alkaline Mono Lake in California. The Gram-positive, spore-forming, slightly curved rods with sizes 0.55-0.7x1.7-3.0 microm were motile by a single laterally attached flagellum. Strain APO was mesophilic (range 10-48 degrees C, optimum of 37 degrees C); halophilic (NaCl range 1-20% (w/v) with optimum of 3-5% (w/v), and alkaliphilic (pH range 8.0-10.5, optimum 9.5). The novel isolate required sodium ions in the medium. Strain APO was an organotroph with a fermentative type of metabolism and used the substrates peptone, bacto-tryptone, casamino acid, yeast extract, l-serine, l-lysine, l-histidine, l-arginine, and pyruvate. The new isolate performed the Stickland reaction with the following amino acid pairs: proline + alanine, glycine + alanine, and tryptophan + valine. The main end product of growth was acetate. High activity of CO dehydrogenase and hydrogenase indicated the presence of a homoacetogenic, non-cycling acetyl-CoA pathway. Strain APO was resistant to kanamycin but sensitive to chloramphenicol, tetracycline, and gentamycin. The G+C content of the genomic DNA was 44.4 mol% (by HPLC method). The sequence of the 16S rRNA gene of strain APO possessed 98.2% similarity with the sequence from Tindallia magadiensis Z-7934, but the DNA-DNA hybridization value between these organisms was only 55%. On the basis of these physiological and molecular properties, strain APO is proposed to be a novel species of the genus Tindallia with the name Tindallia californiensis sp. nov., (type strain APO = ATCC BAA-393 = DSM 14871).     

Isolation, characterization, and polyaromatic hydrocarbon degradation potential of aerobic bacteria from marine macrofaunal burrow sediments and description of Lutibacterium anuloederans gen. nov., sp. nov., and Cycloclasticus spirillensus sp. nov.

Two new polyaromatic hydrocarbon-degrading marine bacteria have been isolated from burrow wall sediments of benthic macrofauna by using enrichments on phenanthrene. Strain LC8 (from a polychaete) and strain M4-6 (from a mollusc) are aerobic and gram negative and require sodium chloride (>1%) for growth. Both strains can use 2- and 3-ring polycyclic aromatic hydrocarbons as their sole carbon and energy sources, but they are nutritionally versatile. Physiological and phylogenetic analyses based on 16S ribosomal DNA sequences suggest that strain M4-6 belongs to the genus Cycloclasticus and represents a new species, Cycloclasticus spirillensus sp. nov. Strain LC8 appears to represent a new genus and species, Lutibacterium anuloederans gen. nov., sp. nov., within the Sphingomonadaceae. However, when inoculated into sediment slurries with or without exogenous phenanthrene, only L. anuloederans appeared to sustain a significant phenanthrene uptake potential throughout a 35-day incubation. In addition, only L. anuloederans appeared to enhance phenanthrene degradation in heavily contaminated sediment from Little Mystic Cove, Boston Harbor, Boston, Mass.     

Haloalkaliphilic spore-forming sulfidogens from soda lake sediments and description of Desulfitispora alkaliphila gen. nov., sp. nov.

An anaerobic enrichment with pyruvate as electron donor and thiosulfate at pH 10 and 0.6 M Na⁺ inoculated with pasteurized soda lake sediments resulted in a sulfidogenic coculture of two morphotypes of obligately anaerobic haloalkaliphilic endospore-forming clostridia, which were further isolated in pure culture. Strain AHT16 was a thin long rod able to ferment sugars and pyruvate and to respire H₂, formate and pyruvate using thiosulfate and fumarate as electron acceptors and growing optimally at pH 9.5. Thiosulfate was reduced incompletely to sulfide and sulfite. The strain was closely related (99% sequence similarity) to a peptolytic alkaliphilic clostridium Natronincola peptidovorans. Strain AHT17 was a short rod with a restricted respiratory metabolism, growing with pyruvate and lactate as electron donor and sulfite, thiosulfate and elemental sulfur as electron acceptors with a pH optimum 9.5. Thiosulfate was reduced completely via sulfite to sulfide. The ability of AHT17 to use sulfite explained the stability of the original coculture of the two clostridia—one member forming sulfite from thiosulfate and another consuming it. Strain AHT17 formed an independent deep phylogenetic lineage within the Clostridiales and is proposed as a new genus and species Desulfitisporum alkaliphilum gen. nov., sp. nov. (=DSM 22410^T = UNIQEM U794^T).     

Ferrovibrio denitrificans gen. nov., sp. nov., a novel neutrophilic facultative anaerobic Fe(II)-oxidizing bacterium

A neutrophilic Fe(II)-oxidizing bacterium was isolated from the redox zone of a low-salinity spring in Krasnodar krai (Russia), at the FeS-Fe(OH)(3) interface deposited at the sediment surface. The cells of strain Sp-1 were short, thin motile vibrioids with one polar flagellum dividing by binary fission. The optimal values and ranges for pH and temperature were pH 6.2 (5.5-8) and 35?°C (5-45?°C), respectively. The organism was a facultative anaerobe. Strain Sp-1 was capable of organotrophic, lithoheterotrophic and mixotrophic growth with Fe(II) as an electron donor. The denitrification chain was 'disrupted'. Oxidation of Fe(II) was coupled to reduction of NO3 - to NO2 - or of N(2) O to N(2) , as well as under microaerobic conditions, with O(2) as an electron acceptor. The DNA G+C content was 64.2?mol%. According to the results of phylogenetic analysis, the strain was 10.6-12% remote from the closest relatives, members of the genera Sneathiella, Inquilinus, Oceanibaculum and Phaeospirillum within the Alphaproteobacteria. Based on its morphological, physiological and taxonomic characteristics, together with the results of phylogenetic analysis, strain Sp-1 is described as a member of a new genus Ferrovibrio gen. nov., with the type species Ferrovibrio denitrificans sp. nov. and the type strain Sp-1(T) (=?LMG 25817(T) =?VKM B-2673(T) ).     

A novel lineage of sulfate-reducing microorganisms: Thermodesulfobiaceae fam. nov.,<Emphasis Type="Italic"> Thermodesulfobium narugense</Emphasis>, gen. nov., sp. nov., a new thermophilic isolate from a hot spring

A novel type of a sulfate-reducing microorganism, represented by strain Na82T, was isolated from a hot spring in Narugo, Japan. The isolate was a moderate thermophilic autotroph that was able to grow on H2/CO2 by sulfate respiration. The isolate could grow with nitrate in place of sulfate, and possessed menaquinone-7 and menaquinone-7(H2) as respiratory quinones. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Na82T was a member of the domain Bacteria and distant from any known bacteria, as well as from other sulfate-reducing bacteria (sequence similarities less than 80%). The phylogenetic analysis of the dsrAB gene (alpha and beta subunits of dissimilatory sulfite reductase) sequence also suggested that strain Na82T was not closely related to other sulfate reducers. On the basis of the phenotypic and phylogenetic data, a new taxon is established for the isolate. We proposed the name Thermodesulfobium narugense gen. nov., sp. nov. with strain Na82T (=DSM 14796T=JCM 11510T) as the type strain. Furthermore, a new family, Thermodesulfobiaceae fam. nov., is proposed for the genus.     

Chthoniobacter flavus gen. nov., sp. nov., the first pure-culture representative of subdivision two, Spartobacteria classis nov., of the phylum Verrucomicrobia

The phylum Verrucomicrobia is increasingly recognized as an environmentally significant group of bacteria, particularly in soil habitats. At least six subdivisions of the Verrucomicrobia are resolved by comparative analysis of 16S rRNA genes, mostly obtained directly from environmental samples. To date, only two of these subdivisions (1 and 4) have characterized pure-culture representatives. We have isolated and characterized the first known pure-culture representative of subdivision 2. Strain Ellin428 is an aerobic heterotrophic bacterium that is able to grow with many of the saccharide components of plant biomass but does not grow with amino acids or organic acids other than pyruvate. Cells are yellow, rod-shaped, nonmotile, and gram-stain negative, and they contain peptidoglycan with direct cross-linkages of the A1 gamma meso-Dpm type. The isolate grows well at 25 degrees C on a variety of standard biological media, including some used in the routine cultivation of bacteria from soil. The pH range for growth is 4.0 to 7.0. Low levels of menaquinones MK-10 and MK-11 were detected. The major cellular fatty acids are C(14:0), a-C(15:0), C(16:1 omega 7c), and/or 2OH i-C(15:0), and C(16:0). The G+C content of the genomic DNA is 61 mol%. We propose a new genus and species, Chthoniobacter flavus gen. nov., sp. nov., with isolate Ellin428 as the type strain, and a new class for the subdivision to which it belongs, Spartobacteria classis nov. Environmental sequences indicate that the class Spartobacteria is largely represented by globally distributed, abundant, and active soil bacteria.     

Geoalkalibacter ferrihydriticus gen. nov., sp. nov., the first alkaliphilic representative of the family Geobacteraceae, isolated from a soda lake

Investigation of iron reduction in bottom sediments of alkaline soda lakes resulted in the isolation of a new obligately anaerobic iron-reducing bacterium, strain Z-0531, from Lake Khadyn (Tuva Republic, Russia) sediment samples. The cells of strain Z-0531 are short (1.0-1.5 by 0.3-0.5 microm), motile, non-spore-forming, gram-negative rods. The isolate is an obligate alkaliphile, developing in the pH range of 7.8-10.0, with an optimum at pH 8.6. It does not require NaCl but grows at NaCl concentrations of 0-50 g/1l. It can oxidize acetate with such electron acceptors as amorphous Fe(llI) hydroxide (AFH), EDTA-Fe(III), anthraquinone-2,6-disulfonate (quinone), Mn(IV), and S(0). On media with EDTA-Fe(III), the isolate can oxidize, apart from acetate, ethanol, pyruvate, oxalate, arginine, tartrate, lactate, propionate, and serine. H2 is not utilized. The reduced products formed during growth with AFH are siderite or magnetite, depending on the growth conditions. The isolate is incapable of fermenting sugars, peptides, and amino acids. Yeast extract or vitamins are required as growth factors. The organism is capable of dinitrogen fixation and harbors the nifH gene. The DNA G+C content is 55.3 mol %. 16S rRNA analysis places strain Z-0531 into the family Geobacteraceae. Its closest relative (93% similarity) is Desulfuromonas palmitatis. Based on phenotypic distinctions and phylogenetic position, it is proposed that strain Z-0531 be assigned to the new genus and species Geoalkalibacter ferrihydriticus gen. nov., sp. nov.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

Natronorubrum texcoconense sp. nov., a haloalkaliphilic archaeon isolated from soil of the former lake Texcoco (Mexico)

A new haloalkaliphilic archaeon, strain B4^T, was isolated from the former lake Texcoco in Mexico. The cells were Gram-negative, pleomorphic-shaped, pink to red pigmented and aerobic. Strain B4^T required at least 2.5 M NaCl for growth, with optimum growth at 3.4 M NaCl. It was able to grow over a pH range of 7.5–10.0 and temperature of 25–50 °C, with optimal growth at pH 9 and 37 °C. Cells are lysed in hypotonic treatment with less than 1.3 M NaCl. The major polar lipids of strain B4^T were phosphatidylglycerol and methyl-phosphatidylglycerophosphate. Phospholipids were detected, but not glycolipids. The nucleotide sequence of the 16S rRNA gene revealed that the strain B4^T was phylogenetically related to members of the genus Natronorubrum. Sequence similarity with Natronorubrum tibetense was 96.28 %, with Natronorubrum sulfidifaciens 95.06 % and Natronorubrum sediminis 94.98 %. The G+C content of the DNA was 63.3 mol%. The name of Natronorubrum texcoconense sp. nov. is proposed. The type strain is B4^T (=CECT 8067^T = JCM 17497^T).     

Halomonas campaniensis sp. nov., a haloalkaliphilic bacterium isolated from a mineral pool of Campania Region, Italy

A Gram-negative, aerobic, motile and rod-shaped haloalkaliphilic bacterial strain 5AGT (DSM 15293 and ATCC BAA-966) was isolated from water with algal mat of a mineral pool in Malvizza site (Campania-Italy) and was subjected to a polyphasic study. The isolate grew at temperature of 10.0-43.0 degrees C with an optimum at 37.0 degrees C. Strain 5AGT grew optimally in the presence of 10% NaCl and grew also in the absence of salt. The isolate grew in the pH range 7.0-10.0 with an optimum at pH 9.0. It accumulated glycine-betaine, ectoine, and glutamate, as osmoprotectants. Strain 5AGT was also characterized chemotaxonomically by having ubiquinone-8 (Q8) as the predominant isoprenoid quinone, phosphoethanolamine (PEA), phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG), as major polar lipids and aiC16:0 and C18:1cis as the major fatty acids. The DNA G+C content was 63.7mol%. Phylogenetic analyses based on 16S rRNA gene sequence showed that the isolate belonged to the genus Halomonas. The DNA-DNA hybridization of the type strain 5AGT with the most related Halomonas campisalis showed a re-association value of 35.0%.On the basis of phenotypic properties and phylogeny, strain 5AGT should be placed in the genus Halomonas as a member of a novel species for which we propose the name Halomonas campaniensis sp. nov.     

Isolation and description ofHaloanaerobium praevalens gen. nov. and sp. nov., an obligately anaerobic halophile common to Great Salt Lake sediments

A new halophilic species is described that was isolated from the hypersaline (>20%) surface sediments of Great Salt Lake, Utah, via transfer from MPN end-dilution tubes that contained a complex organic medium. The organism was an obligate anaerobe that proliferated optimally at approximately 13% salt, but did not grow significantly at <2% or ≥30% salt. It stained Gram-negative, was nonmotile, nonsporing, and contained an outer-wall membranous layer. The complex lipids of the organism were fatty acid esters that did not change dramatically during growth at 5% or 25% NaCl. The DNA base composition was 27.0±1 mol% guanosine plus cytosine. The temperature range for growth was >5°C and <60°C, the pH range was between 6.0 and 9.0. The doubling time for growth in complex medium with 25% NaCl was 7 h. The organism utilized carbohydrates, peptides, and amino acids. Butyrate, acetate, propionate. H₂, and CO₂ were the major fermentation end products formed. Glucose, mannose, fructose,n-acetyl glucosamine, and pectin were used as energy sources for growth. Methylmercaptan was produced from methionine degradation. The nameHaloanaerobium praevalens gen. nov. sp. nov. is proposed for the type strain GSL which has been deposited as DSM 2228. The taxonomic relationships ofH. praevalens to other obligate halophiles and anaerobes, as well as its biological role in the Great Salt Lake microbial ecosystem, are discussed.     

Mycoplasma simbae sp. nov., Mycoplasma leopharyngis sp. nov., and Mycoplasma leocaptivus sp. nov., isolated from lions.

Mycoplasmas isolated from the throats of lions were shown to belong to three serotypes, all of which were serologically distinct from the previously recognized Mycoplasma and Acholeplasma spp. Eight mycoplasma colonies were cloned, including one from a leopard (strain LP), and were examined in detail for morphology, growth, and biochemical characteristics. The strains had the following properties: guanine-plus-cytosine contents of 37 mol% (strain LXT [T = type strain]), 28 mol% (strain LL2T), and 27 mol% (strain 3L2T) and a requirement for sterol. Strain 3L2T metabolized glucose, which was not metabolized by strains LXT and LL2T. Arginine and urea were not hydrolyzed. Strain LX (= NCTC 11724) is the type strain of a new species, Mycoplasma simbae; strain LL2 (= NCTC 11725) is the type strain of a second new species, Mycoplasma leopharyngis; and strain 3L2 (= NCTC 11726) is the type strain of a third new species, Mycoplasma leocaptivus.     

Halomonas campisalis sp. nov., a denitrifying, moderately haloalkaliphilic bacterium

The isolation and characterization of a denitrifying bacterium that is both moderately halophilic and alkaliphilic is described. The organism was isolated for use in the development of a bioprocess that could potentially reduce the costs of ion exchange resin regenerant disposal. The process of ion exchange, after resin regeneration, produces a briny, alkaline waste that is difficult and expensive to dispose. The biological removal of nitrate and subsequent reuse of these brines can potentially provide a cost-saving alternative to disposing of this waste product. To achieve our objective, a moderately halophilic, alkaliphilic bacterium was isolated from sediment samples taken from the salt plain of Alkali Lake in Washington State (USA). The haloalkaliphilic bacterium, designated strain 4A, is motile with rod-shaped cells that are 3 to 5 microm long and 1 microm wide. Electron acceptors used include oxygen, nitrate, and nitrite. In addition, it has similar specific nitrate reduction rates and biomass yields as non-halophilic denitrifying bacteria. It is capable of using a variety of electron donors. This organism can grow at NaCl concentrations ranging from 0.2 to 4.5 M with optimum growth occurring at 1.5 M and pH values ranging from 6 to 12 with 9.5 being the optimum pH. The temperature range for growth of strain 4A is 4-50 degrees C with optimal growth occurring at 30 degrees C. The G + C content is 66 mol%. Phylogenetic analyses based upon 16S rDNA gene sequence placed isolate 4A in the genus Halomonas. In addition, DNA-DNA hybridization experiments clearly indicate that it is a unique species. Phenotypic and phylogenetic studies indicate that isolate 4A represents a new species. We propose the name Halomonas campisalis for this species and strain 4A (ATCC 700597) as the type strain. Due to its denitrification ability, broad carbon utilization range and its high salinity and pH tolerance this organism, and similar ones, hold promise for the treatment of saline, alkaline waste.     

Comamonas badia sp. nov., a floc-forming bacterium isolated from activated sludge

Strain IAM 14839, isolated from activated sludge in Japan, forms a visible floc and grows in the flocculated state. This bacterium is Gram-negative, rod-shaped, strictly aerobic and highly motile with a single polar flagellum. Both oxidase and catalase activities are positive. No growth was observed on sugars. The strain can grow at 20 degrees C, but does not grow at 37 degrees C. The G+C content of DNA is 66.3 mol% and Q-8 is the major quinone. The major cellular fatty acids are 16:1omega7c, 16:0, 18:1omega7c, 2OH 16:0, 3OH 10:0. The 16S rDNA sequence analysis indicated that the bacterium clustered within the genus Comamonas. On the basis of the phylogenetic analysis and phenotypic properties, it is proposed that the strain IAM 14839T be classified in a novel species of the genus Comamonas, Comamonas badia sp. nov. The type strain is IAM 14839T (=KCTC 12244T ).