[The new facultatively chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium Desulfovermiculus halophilus gen. nov., sp. nov., isolated from an oil field].

The new mesophilic, chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium strain 11-6 could grow at a NaCl concentration in the medium of 30-230 g/l, with an optimum at 80-100 g/l. Cells were vibrios motile at the early stages of growth. Lactate, pyruvate, malate, fumarate, succinate, propionate, butyrate, crotonate, ethanol, alanine, formate, and H2 + CO2 were used in sulfate reduction. Butyrate was degraded completely, without acetate accumulation. In butyrate-grown cells, a high activity of CO dehydrogenase was detected. Additional growth factors were not required. Autotrophic growth occurred, in the presence of sulfate, on H2 + CO2 or formate without other electron donors. Fermentation of pyruvate and fumarate was possible in the absence of sulfate. Apart from sulfate, sulfite, thiosulfate, and elemental sulfur were able to serve as electron acceptors. The optimal growth temperature was 37 degrees C; the optimum pH was 7.2. Desulfoviridin was not detected. Menaquinone MK-7 was present. The DNA G+C content was 55.2 mol %. Phylogenetically, the bacterium represented a separate branch within the cluster formed by representatives of the family Desulfohalobiaceae in the subclass Deltaproteobacteria. The bacterium was assigned to a new genus and species, Desulfovermiculus halophilus gen. nov., sp. nov. The type strain is 11-6T (= VKM B-2364), isolated from the highly mineralized formation water of an oil field.

[The properties of hydrocarbon-oxidizing bacteria isolated from the oilfields of Tatarstan, Western Siberia, and Vietnam].

Eleven strains of hydrocarbon-oxidizing bacteria, isolated from oilfields, representing the genera Rhodococcus, Gordonia, Dietzia, and Pseudomonas, were characterized as mesophiles and neutrophiles. Rhodococci were halotolerant microorganisms growing in a media containing up to 15% NaCl. All the strains oxidized n-alkanes of crude oil. An influence of the cultivation temperatures (28 or 45 degrees C) and organic supplements on the degradation of C12-C30 n-alkanes in oxidized oil by two bacterial strains of the genus Pseudomonas was shown. The introduction of acetate, propionate, butyrate, ethanol, and sucrose led mainly to the decreased oxidation of petroleum paraffins. At certain cultivation temperatures, the addition of volatile fatty acid salts increased the content of individual n-alkanes in oxidized vs. crude oil.

[Description of Desulfotomaculum nigrificans subsp. salinus as a new species, Desulfotomaculum salinum sp. nov].

This study focused on the physiological, chemotaxonomic, and genotypic characteristics of two thermophilic spore-forming sulfate-reducing bacterial strains, 435T and 781, of which the former has previously been assigned to the subspecies Desulfotomaculum nigrificans subsp. salinus. Both strains reduced sulfate with the resulting production of H2S on media supplemented with H2 + CO2, formate, lactate, pyruvate, malate, fumarate, succinate, methanol, ethanol, propanol, butanol, butyrate, valerate, or palmitate. Lactate oxidation resulted in acetate accumulation; butyrate was oxidized completely, with acetate as an intermediate product. Growth on acetate was slow and weak. Sulfate, sulfite, thiosulfate, and elemental sulfur, but not nitrate, served as electron acceptors for growth with lactate. The bacteria performed dismutation of thiosulfate to sulfate and hydrogen sulfide. In the absence of sulfate, pyruvate but not lactate was fermented. Cytochromes of b and c types were present. The temperature and pH optima for both strains were 60-65 degrees C and pH 7.0. Bacteria grew at 0 to 4.5-6.0% NaCl in the medium, with the optimum being at 0.5-1.0%. Phylogenetic analysis based on a comparison of incomplete 16S rRNA sequences revealed that both strains belonged to the C cluster of the genus Desulfotomaculum, exhibiting 95.5-98.3% homology with the previously described species. The level of DNA-DNA hybridization of strains 435T and 781 with each other was 97%, while that with closely related species D. kuznetsovii 17T was 51-52%. Based on the phenotypic and genotypic properties of strains 435T and 781, it is suggested that they be assigned to a new species: Desulfotomaculum salinum sp. nov., comb. nov. (type strain 435T = VKM B 1492T).

[Microorganisms in heat supply lines and internal corrosion of steel pipes]. / Mikroorganizmy v teplovykh setiakh i vnutrenniaia korroziia stal'nykh truboprovodov.

In laboratory experiments with batch cultures of thermophilic microorganisms isolated from urban heat supply systems, the growth of sulfate-reducing, iron-oxidizing, and iron-reducing bacteria was found to accelerate the corrosion rate of the steel-3 plates used in the pipelines. In the absence of bacteria and dissolved oxygen, minimal, corrosion was determined. The aforementioned microorganisms, as well as sulfur-oxidizing bacteria, were found to be widespread in water and corrosion deposits in low-alloy steel pipelines (both delivery and return) of the Moscow heat networks, as well as in the corrosion deposits on the steel-3 plates in a testing unit supplied with the network water. The microorganisms were found in samples with water pH ranging from 8.1 to 9.6 and a temperature lower than 90 degrees C. Magnetite, lepidocrocite, goethite, X-ray amorphous ferric oxide were the corrosion products identified on the steel-3 plates, as well as siderite, aragonite, and S0. The effect of microbiological processes on the rate of electrochemical corrosion was evaluated from the accumulation of corrosion deposits and from variation in total and local corrosion of the steel plates in a testing unit.

[Desulfacinum subterraneum sp.nov.--a new thermophilic sulfate-reducing bacterium isolated from a high temperature oil field ]. / Desulfacinum subterraneum sp.nov--novaia termofil'naia sul'fatvosstanavlivaiushchaia bakteriia, vydelennaia iz vysokotemperaturnogo neftianogo plasta.

A new thermophilic sulfate-reducing bacterium isolated from the high-temperature White Tiger oil field (Vietnam) is described. Cells of the bacterium are oval (0.4-0.6 by 0.6-1.8 microns), nonmotile, non-spore-forming, and gram-negative. Growth occurs at 45 to 65 degrees C (with an optimum at 60 degrees C) at NaCl concentrations of 0 to 50 g/l. In the course of sulfate reduction, the organism can utilize lactate, pyruvate, malate, fumarate, ethanol, salts of fatty acids (formate, acetate, propionate, butyrate, caproate, palmitate), yeast extract, alanine, serine, cysteine, and H2 + CO2 (autotrophically). In addition to sulfate, the bacterium can use sulfite, thiosulfate, and elemental sulfur as electron acceptors. In the absence of electron acceptors, the bacterium can ferment pyruvate and yeast extract (a yet unrecognized capacity of sulfate reducers) with the formation of acetate and H2. The G + C content of DNA is 60.8 mol %. The level of DNA-DNA hybridization of the isolate (strain 101T) and Desulfacinum infernum (strain B alpha G1T) is as low as 34%. Analysis of the nucleotide sequence of 16S rDNA places strain 101T in the phylogenetic cluster of the Desulfacinum species within the sulfate reducer subdivision of the delta subclass of Proteobacteria. All these results allowed the bacterium studied to be described as a new species, Desulfacinum subterraneum sp. nov., with strain 101 as the type strain.

[Microbiological processes in a high-temperature oil field]. / Mikrobiologicheskie protsessy v vysokotemperaturnom neftianom mestorozhdenii.

Thermophilic sulfate-reducing bacteria (SRB) oxidizing lactate, butyrate, and C12-C16 n-alkanes of oil at a temperature of 90 degrees C were isolated from samples of water and oil originating from oil reservoirs of the White Tiger high-temperature oil field (Vietnam). At the same time, no thermophiles were detected in the injected seawater, which contained mesophilic microorganisms and was the site of low-temperature processes of sulfate reduction and methanogenesis. Thermophilic SRB were also found in samples of liquid taken from various engineering reservoirs used for oil storage, treatment, and transportation. These samples also contained mesophilic SRB, methanogens, aerobic oil-oxidizing bacteria, and heterotrophs. Rates of bacterial production of hydrogen sulfide varied from 0.11-2069.63 at 30 degrees C and from 1.18-173.86 at 70 degrees C micrograms S/(1 day); and those of methane production, varied from 58.4-100 629.8 nl CH4/(1 day) (at 30 degrees C). The sulfur isotopic compositions of sulfates contained in reservoir waters and of hydrogen sulfide of the accompanying gas indicate that bacterial sulfate reduction might be effective in the depth of the oil field.

[Ecologic conditions for the spread of methane-forming bacteria in the petroleum strata of Apsheron]. / Ekologicheskie usloviia rasprostraneniia metanoobrazuiushchikh bakterii v neftianykh plastakh Apsherona.

The distribution of methan producing bacteria was studied in oil bearing strata of the Apsheron Peninsula and was shown to depend on ecological conditions: the total mineralization of stratal water, the content of hydrogen sulfide, sulfates, the pH, the extent of penetration of surface waters. The bacteria was found in 11 among 14 stratal water samples taken from the studied oil deposits. The flooding of oil collectors with surface waters was shown to be one of the factors responsible for the distribution of methane producing bacteria in the stratal waters of oil deposits. Methane producing cenoses were found in stratal water whose mineralization varied from 17 to 84.8 g per litre and the content of hydrogen sulfide varied from 0 to 585 mg per litre. Most of the samples contained also sulfate reducing bacteria which grew in a medium with lactate, as well as fermenting microorganisms which grew in the presence of peptone and glucose and supplied methane producing bacteria with their substrates, viz. H2, CO2 and acetate. Preliminary experiments in which methane was produced from oil via a two-stage process suggest that flooding favours the formation of oil oxidation products in the strata and these products serve as substrates for the growth of microbial cenoses producing methane.

[Distribution of thermophilic sulfate reducing bacteria in the oil-bearing strata of Apsheron and Western Siberia]. / Rasprostranenie termofil'nykh sul'fatvosstanavlivaiushchikh bakterii v neftianykh plastakh Apsherona i Zapadnoi Sibiri.

Enrichment cultures of sulfate-reducing bacteria were obtained by inoculating the water of high-temperature gas and oil-bearing strata. A study of the morphology of these cells has shown that the thermophilic bacterium Desulfovibrio thermophilus occurs in the deposits of the Apsheron Peninsula while Desulfootomaculum nigrificans is found in the deposits of West Siberia. The former organism is involved in the accumulation of H2S in the Apsheron strata. The temperature of the strata is believed to be the factor which regulates the incidence of bacteria.

[Fixation of molecular nitrogen by sulfate-reducing bacteria from petroleum strata]. / Kiksatsiia molekulairnogo azota sul'fatvosstanavlivaiushchimi bakteriiami iz neftianykh plastov.

The activity of nitrogen fixation by the museum strains of sulfate reducing bacteria isolated from oil deposits was studied using the acetylene technique. The mesophilic sulpfate reducing bacteria belonging to the species Desulfovibrio africanus 2372 and D. baculatus X were found to have a high nitrogenase activity. D desulfuricans subsp. aestuarii 2198 reduced acetylene at a low rate. The thermophilic sulfate reducing cultures of D. thermophilus 7, Desulfotomaculum nigrificans 781 and Dm. nigrificans subsp. salinus 435 produced only small quantities of ethylene. Apparently, nitrogen fixation by sulfate reducing bacteria can be considerable in oil strata whose temperature does not exceed 35--40 degrees C.

[Sulfate reduction and the water-soluble organic substances in a flooded petroleum bed]. / Sul'fatreduktsiia i vodno-rastvorennye organicheskie veshchestva v zavodniaemom neftianom plaste.

The paper presents the analytical data for the hydrochemical and microbiological composition of the water in a stratum undergoing changes as a result of artificial flooding. The highest accumulation of biogenic H2S and the carbon of dissolved organic substance was found in diluted bed waters with mineralization of 17.17 g/litre. The composition of the bitumen carbon of dissolved organic substances changed with dilution of the stratum brine. The data thus obtained suggest the existence of an indirect relationship; oxidized dissolved organic substance--the rate of sulphate reduction. The nature of organic substance appearing in the petroleum stratum is discussed.

[Thermophillic sulfate-reducing bacteria from oil-bearing strata]. / Termofil'nye sul'fatvosstanavlivaiushchie bakterii iz neftaianykh plastov.

The paper describes pure cultures (strains 435 and 781) of thermophilic spore-forming sulphate-reducing bacteria isolated from oil strata. The strain 435 was classed as a new subspecies Desulfotomaculum nigrificnas subsp. salinus according to its morphological, physiological, and biochemical characteristics. The cells of the culture are rod-like, 2-5 mcm long and 0.9-1.3 mcm thick. Some cells are spindle-shaped. The cells have peritrichously arranged flagella. Spores are oval, located terminally or subterminally, slightly widening the cells. The culture is an obligate anaerobe. It grows in media containing sulphates and assimilates sodium salts of lactic, pyruvic, malic and formic acids, ethanol, and butanol. The cuture assimilates pyruvate in the absence of sulphates. Sulphate, sulphite and thiosulphate are electron acceptors when the culture grows on lactate. The organism can grow at 40-70 degrees C, the optimum temperature being 60 degrees C. It requires NaCl for growth, and can grow even in the presence of 4% NaCl in the medium. The optimum should contain 1% NaCl and microelements. Desulfoviridin is absent. The cells contain a cytochrome of the protoheme class. The content of G + C base pairs in DNA is 57.0 +/- 0.5 mol. %.

[Microbiological studies of the Wanda Lake (Antarctica)]. / Mikrobiologicheskie issledovaniia ozera Vanda (Antarktida)

The deep-water (68 m) Wanda Lake in the Antarctica is noticeable by three characteristics: a relatively high temperature in the bottom layer, elevated salinity, and the presence of H2S. Only several (less often, dozens) saprophytic microorganisms per 40 ml of water are encountered in the lake. The total number of bacteria varies from 6-10(3) to 172-10(3) cells/ml. The highest content of the total bacterial population, and saprophytes, is found in intermediate layers, 30 and 40-50 m deep, respectively. Microbial strains isolated from water and ooze belong to the genera Pseudomonas, Chromobacterium, Bacillus, and Mycobacterium. Yeast organisms were also found. Sulphate reducing bacteria were detected only at one station in ooze of the lake while thionic bacteria could not be determined at all. Photosynthetic bacteria were isolated from ooze at all four stations.

[Mesophilic rod-like nonsporeforming bacterium reducing sulfates]. / Mezofil'naia palochkovidnaia bessporovaia bakteriia, vosstanavliviushchaia sul'faty

A pure culture of a new organism, strain X, reducing sulphates is described. According to its morphological, physiological and biochemical properties, the organism is classed as a new species. Desulfovibrio baculatus nov. sp. The cells have the shape of short rods, 1.3X0.6 mcm, with a polar flagellum 0.021 mcm thick. It is an obligate anaerobic culture growing on media only in the presence of sulphates at the account of sodium salts of lactic, pyruvic and malic acids and also in the presence of yeast autolysate at the account of formate and hydrogen. Sulphate, sulphite and thiosulphate can serve as acceptors of electrons during growth on lactate. The organism grows at 2 to 41 degree C in the presence of up to 6% NaCl in the medium and does not require NaCl for its growth. The cells do not contain desulphoviridine as was proved by fluorescence. Hemes of cytochromes b and c were found in the cells. The content of G+C base pairs in DNA is 56.8+/-0.4 mole %. The culture was isolated from dumps of manganese ore.

[Biogenic elements and sulfate reduction in a flooded oil carbonate stratum]. / Biogennye élementy i sul'fatreduktsiia v zavodniaemom neftianom karbonatnom plaste

Biogenous sulphate reduction and accumulation of secondary H2S were caused by the action of pumping waters with a low content of mineral elements on carbonate collectors with a high concentration of relict H2S during long periods of time. The amount of sulphates, phosphates, and ammonium nitrogen in water from layers of various mineralization is sufficient for active sulphate reduction. Sulphates and phosphates are eliminated from rocks of layers with diluted waters. The maximum increase of SO42- in waters was 1545 mg/litre, that of HPO42- was 0.34 mg/litre. The amount of ammonium decreases with mineralization of the layer waters, remaining within the range of 129-7 mg/litre. The content of CO2 and HCO3- increases in diluted waters to 197 and 695 mg/litre, respectively, correlating with biogenous processes. The highest number of sulphate reducing bacteria (dozens of thousands of the cells per ml) was found in water with mineralization of 19 g/litre. Curves for the content of SO42-, HPO42-, NH4+, and CO2 have a common maximum in waters of the Polaznensky deposit with a salinity of 62 g/litre.