Degradation of hydroxyhydroquinone by the strictly anaerobic fermenting bacterium Pelobacter massiliensis sp. nov.

A new rod-shaped, gram-negative, non-sporeforming, strictly anaerobic bacterium (strain HHQ7) was enriched and isolated from marine mud samples with hydroxyhydroquinone (1,2,4-trihydroxybenzene) as sole substrate. Strain HHQ7 fermented hydroxyhydroquinone, pyrogallol (1,2,3-trihydroxybenzene), phloroglucinol (1,3,5-trihydroxybenzene) and gallic acid (3,4,5-trihydroxybenzoate) to 3 mol acetate (plus 1 mol CO₂ in the case of gallic acid) per mol of substrate. Resorcinol accumulated intermediately during growth on hydroxy-hydroquinone. No other aliphatic or aromatic substrates were utilized. Sulfate, sulfite, sulfur, nitrate, and fumarate were not reduced with hydroxyhydroquinone as electron donor. The strain grew in sulfide-reduced mineral medium supplemented with 7 vitamins. The DNA base ratio was 59% G+C. Strain HHQ7 is classified as a new species of the genus Pelobacter, P. massiliensis. Experiments with dense cell suspensions of hydroxyhydroquinone-and pyrogallol-grown cells showed different kinetics of hydroxyhydroquinone and pyrogallol degradation, as well as different patterns of resorcinol accumulation, indicating that these substrates are metabolized by different transhydroxylation reactions.     

Desulfovibrio brasiliensis sp. nov., a moderate halophilic sulfate-reducing bacterium from Lagoa Vermelha (Brazil) mediating dolomite formation

A novel halotolerant sulfate-reducing bacterium, Desulfovibrio brasiliensis strain LVform1, was isolated from sediments of a dolomite-forming hypersaline coastal lagoon, Lagoa Vermelha, in the state of Rio de Janeiro, Brazil. The cells are vibrio-shaped and 0.30 to 0.45 m by 1.0 to 3.5 m in size. These bacteria mediate the precipitation of dolomite [CaMg(CO₃)₂] in culture experiments. The strain was identified as a member of the genus Desulfovibrio in the -subclass of the Proteobacteria on the basis of its 16S rRNA gene sequence, its physiological and morphological properties. Strain LVform1 is obligate sodium-dependent and grows at NaCl concentrations of up to 15%. The 16S rRNA sequence revealed that this strain is closely related to Desulfovibrio halophilus (96.2% similarity) and to Desulfovibrio oxyclinae (96.8% similarity), which were both isolated from Solar Lake, a hypersaline coastal lake in the Sinai, Egypt. Strain LVform1 is barotolerant, growing under pressures of up to 370 bar (37 MPa). We propose strain LVform1 to be the type strain of a novel species of the genus Desulfovibrio, Desulfovibrio brasiliensis (type strain LVform1 = DSMZ No. 15816 and JCM No. 12178). The GenBank/EMBL accession number for the 16S rDNA sequence of strain LVform1 is AJ544687.     

Succinate decarboxylation byPropionigenium maris sp. nov., a new anaerobic bacterium from an estuarine sediment

Enrichments on succinate plus yeast extract under anoxic conditions from intertidal mud-flat sediments yielded cultures dominated by oval to round-ended rod-shaped cells. Strain 10succ1, obtained in pure culture, was characterized in detail. The non-motile cells possessed a gram-negative cell wall and did not form spores. Carbohydrates were fermented to formate, acetate, ethanol, and lactate. Succinate was decarboxylated to propionate. Other organic and amino acids were variously fermented to formate, acetate, propionate, and butyrate. Sulfur, sulfate, thiosulfate, and nitrate were not used as electron acceptors. Growth required the presence of yeast extract and at least 5 g/l NaCl, and was possible only in the absence of oxygen. No cytochromes were detected. The DNA base ratio was 40 mol% G+C. Phylogenetically, strain 10succ1 is closely related to Propionigenium modestum, as revealed by 16S rDNA analysis, but is physiologically distinct. Accordingly, strain 10succ1 (DSM 9537) is described as the type strain of a new species of the genus Propionigenium, P. maris sp. nov. Received: 12 January 1995 / Accepted: 24 February 1995     

Hydroxyhydroquinone reductase, the initial enzyme involved in the degradation of hydroxyhydroquinone (1,2,4-trihydroxybenzene) by Desulfovibrio inopinatus

The recently isolated sulfate reducer Desulfovibrio inopinatus oxidizes hydroxyhydroquinone (1,2,4trihydroxybenzene; HHQ) to 2 mol acetate and 2 mol CO2 (mol substrate)-1, with stoichiometric reduction of sulfate to sulfide. None of the key enzymes of fermentative HHQ degradation, i.e. HHQ-1,2,3,5-tetrahydroxybenzene transhydroxylase or phloroglucinol reductase, were detected in cell-free extracts of D. inopinatus, indicating that this bacterium uses a different pathway for anaerobic HHQ degradation. HHQ was reduced with NADH in cell-free extracts to a nonaromatic compound, which was identified as dihydrohydroxyhydroquinone by its retention time in HPLC separation and by HPLC-mass spectrometry. The compound was identical with the product of chemical reduction of HHQ with sodium borohydride. Dihydrohydroxyhydroquinone was converted stoichiometrically to acetate and to an unknown coproduct. HHQ reduction was an enzymatic activity which was present in the cell-free extract at 0.25-0.30 U (mg protein)-1, with a pH optimum at 7.5. The enzyme was sensitive to sodium chloride, potassium chloride, EDTA, and o-phenanthroline, and exhibited little sensitivity towards sulfhydryl group reagents, such as copper chloride or p-chloromercuribenzoate.     

Desulfovibrio longreachii sp. nov., a sulfate-reducing bacterium isolated from the Great Artesian Basin of Australia

Abstract A new mesophilic, thermotolerant sulfate-reducing bacterium, was isolated from the flowing bore waters of a deep aquifer, the Great Artesian Basin, Australia. The strain, designated isolate AB16910a, is a curved rod and resembled members of the genus Desulfovibrio . However, the isolate can be differentiated from other members of the Desulfovibrio species because of the high G+C content of 69±0.25% the 16S rRNA sequence data and other physiological characteristics. The name Desulfovibrio longreachii is proposed for the new isolate.     

Cleavage of dimethylsulfoniopropionate and reduction of acrylate by Desulfovibrio acrylicus sp. nov.

From anoxic intertidal sediment, a dimethylsulfoniopropionate (DMSP)-cleaving anaerobe (strain W218) was isolated that reduced the acrylate formed to propionate. The bacterium was vibrio- to rod-shaped and motile by means of multiple polar flagella. It reduced sulfate, thiosulfate, and acrylate, and used lactate, fumarate, succinate, malate, pyruvate, ethanol, propanol, glycerol, glycine, serine, alanine, cysteine, hydrogen, and formate as electron donors. Sulfate and acrylate were reduced simultaneously; growth with sulfate was faster than with acrylate. Extracts of cells grown in the presence of DMSP contained high DMSP lyase activities (9.8 U/mg protein). The DNA mol% G+C was 45.1. On the basis of its characteristics and the 16S rRNA gene sequence, strain W218 was assigned to a new Desulfovibrio species for which the name Desulfovibrio acrylicus is proposed. A variety of other sulfate-reducing bacteria (eight of them originating from a marine or saline environment and five from other environments) did not reduce acrylate. Received: 22 March 1996 / Accepted: 8 May 1996     

Desulfovibrio Africans sp. n., a new dissimilatory sulfate-reducing bacterium

Campbell, L. Leon (University of Illinois, Urbana), Mary A. Kasprzycki, and John R. Postgate. Desulfovibrio africanus sp. n., a new dissimilatory sulfate-reducing bacterium. J. Bacteriol. 92:1122-1127. 1966.-The strains Benghazi and Walvis Bay can be distinguished from 40 strains of Desulfovibrio and from D. gigas on the basis of morphological and immunological studies. Electron microscopy revealed polar lophotrichous flagellation similar to that of D. gigas but different from the characteristic single polar flagellum of the 40 strains of Desulfovibrio. Immunological evidence shows that the two strains are related to members of the genus Desulfovibrio but possess several common antigenic components not present in the other strains tested. The deoxyribonucleic acid of both strains has a buoyant density of 1.724 g/cc and a guanine plus cytosine content of 60.2%. Cell-free extracts of both organisms show absorption bands of cytochrome c(3) and desulfoviridin, characteristic for Desulfovibrio. The two organisms carry out the sulfate-linked lactate fermentation and neither will grow in the absence of sulfate. Both strains contain the enzymes of the dissimilatory pathway of sulfate reduction. Therefore, these studies have demonstrated that the Benghazi and Walvis Bay strains should be regarded as taxonomically distinct from other species of Desulfovibrio.     

Characterization of Desulfovibrio fructosovorans sp. nov.

Desulfovibrio strain JJ isolated from estuarine sediment differed from all other described Desulfovibrio species by the ability to degrade fructose. The oxidation was incomplete, leading to acetate production. Fructose, malate and fumarate were fermented mainly to succinate and acetate in the absence of an external electron acceptor. The pH and temperature optima for growth were 7.0 and 35° C respectively. Strain JJ was motile by means of a single polar flagellum. The DNA base composition was 64.13% G+C. Cytochrome c ₃ and desulfoviridin were present. These characteristics established the isolate as a new species of the genus Desulfovibrio, and the name Desulfovibrio fructosovorans is proposed.     

Desulfovibrio longus sp. nov., a sulfate-reducing bacterium isolated from an oil-producing well.

A novel type of sulfate-reducing bacteria with unusual morphology was isolated from an oil-producing well in the Paris Basin. The cells of this bacterium, strain SEBR 2582T (T = type strain), are long, thin, flexible rods, contain desulfoviridin, and are physiologically similar to members of the genus Desulfovibrio. On the basis of 16S rRNA sequence data, this strain should be included in the genus Desulfovibrio. However, strain SEBR 2582T differs from other members of this genus morphologically, physiologically, and phylogenetically. Thus, a new species, Desulfovibrio longus sp. nov., is proposed for this organism.     

A sulfate-reducing bacterium from the oxic layer of a microbial mat from Solar Lake (Sinai), Desulfovibrio oxyclinae sp. nov.

In an investigation on the oxygen tolerance of sulfate-reducing bacteria, a strain was isolated from a 10⁷-fold dilution of the upper 3-mm layer of a hypersaline cyanobacterial mat (transferred from Solar Lake, Sinai). The isolate, designated P1B, appeared to be well-adapted to the varying concentrations of oxygen and sulfide that occur in this environment. In the presence of oxygen strain P1B respired aerobically with the highest rates [260 nmol O₂ min^–1 (mg protein)^–1] found so far among marine sulfate-reducing bacteria. Besides H₂ and lactate, even sulfide or sulfite could be oxidized with oxygen. The sulfur compounds were completely oxidized to sulfate. Under anoxic conditions, it grew with sulfate, sulfite, or thiosulfate as the electron acceptor using H₂, lactate, pyruvate, ethanol, propanol, or butanol as the electron donor. Furthermore, in the absence of electron donors the isolate grew by disproportionation of sulfite or thiosulfate to sulfate and sulfide. The highest respiration rates with oxygen were obtained with H₂ at low oxygen concentrations. Aerobic growth of homogeneous suspensions was not obtained. Additions of 1% oxygen to the gas phase of a continuous culture resulted in the formation of cell clumps wherein the cells remained viable for at least 200 h. It is concluded that strain P1B is oxygen-tolerant but does not carry out sulfate reduction in the presence of oxygen under the conditions tested. Analysis of the 16S rDNA sequence indicated that strain P1B belongs to the genus Desulfovibrio, with Desulfovibrio halophilus as its closest relative. Based on physiological properties strain P1B could not be assigned to this species. Therefore, a new species, Desulfovibrio oxyclinae, is proposed. Received: 7 August 1996 / Accepted: 29 January 1997     

Desulforhopalus vacuolatus gen. nov., sp. nov., a new moderately psychrophilic sulfate-reducing bacterium with gas vacuoles isolated from a temperate estuary

A new type of gas-vacuolated, sulfate-reducing bacterium was isolated at 10° C from reduced mud (E₀ < 0) obtained from a temperate estuary with thiosulfate and lactate as substrates. The strain was moderately psychrophilic with optimum growth at 18–19° C and a maximum growth temperature of 24° C. Propionate, lactate, and alcohols served as electron donors and carbon sources. The organism grew heterotrophically only with hydrogen as electron donor. Propionate and lactate were incompletely oxidized to acetate; traces of lactate were fermented to propionate, CO₂, and possibly acetate in the presence of sulfate. Pyruvate was utilized both with and without an electron acceptor present. The strain did not contain desulfoviridin. The G+C content was 48.4 mol%. The differences in the 16S rRNA sequence of the isolate compared with that of its closest phylogenetic neighbors, bacteria of the genus Desulfobulbus, support the assignment of the isolate to a new genus. The isolate is described as the type strain of the new species and genus, Desulforhopalus vacuolatus. Received: 4 March 1996 / Accepted: 17 June 1996     

Isolation and characterization of Desulfovibrio senezii sp. nov., a halotolerant sulfate reducer from a solar saltern and phylogenetic confirmation of Desulfovibrio fructosovorans as a new species

A new halotolerant Desulfovibrio, strain CVL^T (T = type strain), was isolated from a solar saltern in California. The curved, gram-negative, nonsporeforming cells (0.3 × 1.0–1.3 μm) occurred singly, in pairs, or in chains, were motile by a single polar flagellum and tolerated up to 12.5% NaCl. Strain CVL^T had a generation time of 60 min when grown in lactate-yeast extract medium under optimal conditions (37°C, pH 7.6, 2.5% NaCl). It used lactate, pyruvate, cysteine, or H₂/CO₂ + acetate as electron donors, and sulfate, sulfite, thiosulfate, or fumarate as electron acceptors. Elemental sulfur, nitrate, or oxygen were not used. Sulfite and thiosulfate were disproportionated to sulfate and sulfide. The G+C content of the DNA was 62 mol%. Phylogenetic analysis revealed that Desulfovibrio fructosovorans was the nearest relative. Strain CVL^T is clearly different from other Desulfovibrio species, and is designated Desulfovibrio senezii sp. nov. (DSM 8436). Received: 27 February 1998 / Accepted: 15 June 1998     

Stenotrophomonas chelatiphaga sp. nov., a new aerobic EDTA-degrading bacterium

A new ethylenediaminetetraacetic acid (EDTA)-utilizing gammaproteobacterial strain LPM-5^T was isolated from municipal sewage sludge. Aerobic, gram-negative, motile rods multiply by binary fission. Neutrophilic and mesophilic, these are unable to grow in the presence of 3% NaCl (w/v), and unable to reduce nitrate to nitrite, and are oxidase and catalase positive, but lipase negative. The major cellular fatty acids are C_i15:0, C_a15:0 and C_16:1w7c. The dominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol (cardiolipin). The DNA G+C content is 68.3 mol% (T_m). The 16S rRNA gene sequence analysis showed a high similarity of strain LPM-5^T to the species members of genus Stenotrophomonas: S. maltophilia LMG 958^T (98.6%), S. rhizophila CCUG 47042^T (98.3%), S. koreensis TR6-01^T (97.6%) and S. acidaminiphila CIP 106456^T (97.0%). Based on these results and modest DNA–DNA hybridization levels with S. maltophilia VKM B-591^T (=LMG 958^T) (51%) and S. rhizophila CCUG 47042^T (52%), the isolate was classified as a novel species, Stenotrophomonas chelatiphaga sp. nov. (type strain LPM-5^T=VKM B-2486=DSM-21508=CCUG 57178).     

Desulfovibrio alcoholovorans sp. nov., a sulfate-reducing bacterium able to grow on glycerol, 1,2- and 1,3-propanediol

Desulfovibrio strain SPSN was isolated from an anaerobic industrial fermenter fed with waste water from the alcohol industry. The isolate was a gram-negative, non-spore-forming, curved organism, the motility of which is provided by a single polar flagellum. The oxidation of substrates was incomplete and included glycerol and 1,3-propanediol. Sulfate, sulfite, thiosulfate, and sulfur were utilized as electron acceptors. Pyruvate, fumarate and malate could be fermented. The DNA base composition was 64.5±0.3% G+C. Cytochrome c ₃ and desulfoviridin were present. On the basis of these characteristics and because strain SPSN could not be ascribed to any of the existing species, the isolate is established as a new species of the genus Desulfovibrio, and the name Desulfovibrio alcoholovorans is proposed.     

Ilyobacter delafieldii sp. nov., a metabolically restricted anaerobic bacterium fermenting PHB

Enrichments from an estuarine sediment with crotonate as substrate resulted in the isolation of a motile, gram-negative, obligately anaerobic rod with pointed ends, designated strain 10cr1. The organism was asporogenous, did not reduce sulfur, sulfate, thiosulfate, nitrate, oxygen or fumarate, and had a mol %G+C ratio of 29. Strain 10cr1 was able to ferment crotonate, 3-hydroxybutyrate, lactate, pyruvate, and poly--hydroxybutyric acid (PHB). Acetate, propionate, butyrate, CO₂ and H₂ were the fermentation products. When grown on PHB there was accumulation of 3-hydroxybutyrate once growth had ceased, indicating degradation of PHB to the monomer. The 3-hydroxybutyrate formed during growth of the culture was fermented to acetate, butyrate and H₂. Experimental evidence suggested the production of an extracellular PHB depolymerase. The cells were not attached to the PHB granules. This is the first isolation of an anaerobic bacterium capable of degrading exogenous PHB. This strain is described as a new species, Ilyobacter delafieldii sp. nov., and strain 10cr1 (=DSM 5704) is designated as the type (and at present, only) strain.Abbreviations G+C guanine plus cytosine - OD optical density - PHB poly--hydroxybutyric acid - specific growth rate - HPLC high-performance liquid chromatography - YE yeast extract     

Rhodeus pseudosericeus sp. nov., a new bitterling from South Korea (Cyprinidae, Acheilognathinae)

A new bitterling, Rhodeus pseudosericeus sp. nov., is described on the basis of 31 specimens from five localities included in the Namhan River system, South Korea. The new species is distinguished from other Rhodeus species by the following combination of characters: branched dorsal fin rays 9–10 (mode 9); branched anal fin rays 9–11 (mode 10); longest simple ray of dorsal fin strong and stiff, distally segmented; pelvic fin rays i, 6–7; iris of males blackish; dorsal and anal fins of males grayish in breeding season; karyotype with 2n = 48 (8m + 20sm + 20st). Rhodeus pseudosericeus sp. nov. is similar to Rhodeus sericeus sericeus in the number of pelvic fin and branched dorsal fin rays and the melanophores present on the dorsal fin membrane, but differs from the latter in having a greater body depth, more branched anal fin rays, fewer vertebrae, a lower number of scales in the lateral series, and differing male nuptial coloration. Received: June 30, 2000 / Revised: February 21, 2001 / Accepted: March 6, 2001