Extractive compounds of birch buds (<Emphasis Type="Italic">Betula pendula</Emphasis> Roth.): I. Composition of fatty acids,hydrocarbons, and esters

This is the first report devoted to study of the hydrocarbon composition of the extract of buds of European birch Betula pendula (family Betulacea). We have identified saturated (C₁₆ to C₂₈, even number of carbon atoms) and unsaturated (linoleic and linolenic) fatty acids, β-caryophyllene, α-humulene, and the components of epicuticular waxes of cover scales, such as n-alkanes (C₂₁ to C₂₆), esters of fatty acids (C₁₆ to C₂₈, even number of carbon atoms), and fatty alcohols (C₁₈ to C₃₀, even number of carbon atoms). The gas chromatographic retention indices of all identified compounds have been determined.     

Oleispira lenta sp. nov., a novel marine bacterium isolated from Yellow sea coastal seawater in Qingdao, China

The taxonomic position of strain DFH11^T, which was isolated from coastal seawater off Qingdao, People’s Republic of China in 2007, was determined. Strain DFH11^T comprised Gram-negative, motile, strictly aerobic spirilli that did not produce catalase. Comparative 16S rRNA gene sequence analysis revealed that strain DFH11^T shared ~97.2, 93.3, 91.8, 91.7 and 91.5% sequence similarities with Oleispira antarctica, Spongiispira norvegica, Bermanella marisrubri, Oceaniserpentilla haliotis and Reinekea aestuarii, respectively. DNA–DNA hybridization experiments indicated that the strain was distinct from its closest phylogenetic neighbour, O. antarctica. The strain grew optimally in 2–3% (w/v) NaCl, at pH 5.0–10.0 (optimally at pH 7.0) and between 0 and 30°C (optimum growth temperature 28°C). The strain exhibited a restricted substrate profile, with a preference for aliphatic hydrocarbons, that is consistent with its closest phylogenetic neighbour O. antarctica. Growth of the isolate at different temperatures affected the cellular fatty acid profile. 28°C cultured cells contained C_16:1ω7c and/or iso-C_15:0 2-OH (50.4%) and C_16:0 (19.2%) as the major fatty acids. However, the major fatty acids of the cells cultured at 4°C were C_16:1ω7c and/or C_16:1ω6c (40.2%), C_16:0 (17.2%) and C_17:1ω8c (10.1%). The G+C content of the genomic DNA was 42.7 mol%. Phylogeny based on 16S rRNA gene sequences together with data from DNA–DNA hybridization, phenotypic and chemotaxonomic characterization revealed that DFH11^T should be classified as a novel species of the genus Oleispira, for which the name Oleispira lenta sp. nov. is proposed, with the type strain DFH11^T (=NCIMB 14529^T = LMG 24829^T).     

Biodegradation and conversion of alkanes and crude oil by a marine Rhodococcus

A hydrocarbon degrader isolated from a chronically oil-polluted marine site was identified as Rhodococcus sp. on the basis of morphology, fatty acid methyl ester pattern, cell wall analysis, biochemical tests and G + C content of DNA. It degraded upto 50% of the aliphatic fraction of Assam crude oil, in seawater supplemented with 35 mM nitrogen as urea and 0.1 mM phosphorus as dipotassium hydrogen orthophosphate, after 72 h at 30 ° and 150 revolutions per minute. The relative percentage of intracellular fatty acid was higher in hydrocarbon-grown cells compared to fructose-grown cells. The fatty acids C₁₆ , C16_{16 :1} C₁₈ and C_{18 : 1} were constitutively present regardless of the growth substrate. In addition to these constitutive acids, other intracellular fatty acids varied in correlation to the hydrocarbon chain length supplied as a substrate. When grown on odd carbon number alkanes, the isolate released only monocarboxylic acids into the growth medium. On even carbon number alkanes only dicarboxylic acids were produced.     

Identification of the alga known as <Emphasis Type="Italic">Nannochloropsis</Emphasis> Z-1 isolated from a prawn farm in Hainan,China as <Emphasis Type="Italic">Chlorella</Emphasis>

An alga known as “Nannochloropsis”, isolated from a prawn farm in Hainan, China, has been critically investigated and identified as Chlorella, a member of the Chlorophyceae based on fatty acid composition, ultrastructure, and 18S rDNA. Cells of this alga were spherical, measured by 1–6 μm in diameter and were enclosed in thin walls of approximately 0.04 μm thickness. They contained several small mitochondria, two to three thylakoids and had no vacuoles. There were many pyrenoids in the algal cells and their thylakoid lamellae were sparse and not translucent. Many lipid droplets were present in the cytoplasm. The total lipid content of this alga was 3% per gram dry weight and its major fatty acids were C_16:0, C_18:0, C_18:1, C_18:2, C_18:3 and C_20:0. Eicosapentaenoic acid (C_20:5, EPA) was not detected. The length of its 18S rDNA sequence was 1,712 bp. 18S rDNA sequence analyses indicated that this alga was a species of Chlorella.     

Cellular fatty acid composition ofCorallococcus coralloides

The fatty acid composition of five strains ofCorallococcus coralloides and three reference species ofMyxococcus were determined by gas-liquid chromatography. Methyl esters of fatty acid containing from 12 to 22 carbon atoms were identified. The major fatty acids present were C₁₅ and C₁₇ saturated branched chain, and both C₁₆ saturated and unsaturated straight chain acids. The C₁₇ saturated branched and straight chain acids, which were in valuable concentration in species ofMyxococcus, were not, however, detected in all strains ofC. coralloides. The application of these results in the distinction ofC. coralloides from the genusMyxococcus is discussed.     

Fatty acids in green algae cultivated on a pilot-plant scale

Fatty acids fromChlorella vulgaris, Scenedesmus obliquus var.acutus and from a mixed culture of the two strains, Melnik, were converted to methyl esters, separated by gas chromatography, and identified by means of standards. The spectrum of fatty acids included both saturated and unsaturated acids (with odd and even numbers of carbon atoms) from C₁₂ to C₂₂. Fatty acids C_16:0, C_18:0 and C_20:3 were the major components in all cultures. Pure strains differed from the mixed culture in the production of C_18:1, C_12:0 and C_19:2 acids; the first of these was present in higher amounts in pure cultures only, the latter two being found in the mixed culture. The level of lipids was lower as compared to the literature data and their extractability was affected by the manner of preparation of algae and extraction conditions.     

The influence of carbon source on the level and composition of ceramides of the Candida lipolytica yeast

Candida lipolytica yeast was grown batchwise on two different carbon sources, glucose and n-hexadecane. Free ceramides were quantitatively isolated from sphingolipid fractions of total lipids by a combination of column chromatography and preparative thin-layer chromatography. Their composition, after acid methanolysis, was analysed by gas-liquid chromatography. The ceramide content accounted for 2.6% of the total cell lipids in hexadecane-grown cells, which was 1.5 times higher than in glucose-grown cells. The fatty acid composition of ceramides was characterized by the predominance of fatty acids shorter than 20 carbon atoms and by high concentrations of fatty acids with 16 carbon atoms after growth on both carbon sources. The dominant fatty acid was hydroxylated 16:0 in the glucose-grown cells and 16:0 in the hexadecane-grown cells. The striking finding was the low degree of fatty acid hydroxylation and relatively high proportion of odd-numbered fatty acids in ceramide of the n-hexadecane-grown cells. The ceramides contained an unusual long-chain base composition. In hexadecane-grown cells more than 60% of the long-chain bases were C₁₉ phytosphingosine. In glucose-grown cells more than one-half of the total long-chain bases were tetrahydroxy bases, 4,5-dihydroxysphinganine and 4,5-dihydroxyeicosasphinganine. Received: 20 April 1998 / Received revision: 10 July 1998 / Accepted: 29 July 1998     

<Emphasis Type="Italic">Halarchaeum solikamskense</Emphasis> sp. nov., a thermotolerant neutrophilic haloarchaeon from the foamy products of flotation enrichment of potassium minerals

Three pigmented strains of halophilic archaea, RS94-RS96, were isolated from acidic foamy products of flotation enrichment of potassium minerals (Silvinit Co., Solikamsk, Russia). The cells were gram-negative, nonmotile, pleomorphic ovoids, 1.0−1.5 × 1.5−2.5 μm. The isolates were chemoorganotrophic, obligately aerobic, and catalase-positive. A range of carbohydrates and organic acids was used, as well as amino acids and peptides. The strains were halophiles and thermotolerant neutrophiles. They grew in the media with 15 to 30% NaCl (optimum at 20–22%) and 0.005–0.7 M Mg²⁺ (0.1–0.2 M), at pH 5.0–8.2 (optimum 7.0–7.2) and 25–55°C (optimum at 35–50°C). The major fatty acids were C_16:0, C_18:1, C_18:0, and C_16:1. The membranes contained carotenoid pigments of the bacterioruberin series and polar lipids, mostly as C₂₀,C₂₀ isoprenoid derivates: phosphatidylglyceromethylphosphate, phosphatidylglycerol, and three unidentified sulfated glycolipids of the S-DGD type. The DNA G+C content was 65.1–66.4 mol %. Phylogenetic analysis based on the 16S rRNA gene sequencing revealed that the thermotolerant neutrophilic isolate RS94 (DNA G+C content of 66.4 mol %) was most closely related to the nonpigmented moderate acidophile Halarchaeum acidiphilum MH1-52-1^T (97.3%). Based on its phenotypic and genotypic characteristics, the organism was classified as a new species of the genus Halarchaeum with the proposed name Halarchaeum solikamskense sp. nov. The type strain is RS94^T (= VKPM B-11282^T).     

<Emphasis Type="Italic">Acinetobacter brisouii</Emphasis> sp. nov., isolated from a wetland in Korea

A bacterial strain 5YN5-8^T was isolated from peat layer on Yongneup in Korea. Cells of strain 5YN5-8^T were strictly aerobic, Gram-negative, coccobacilli, non-spore forming, and non-motile. The isolate exhibited optimal growth at 28°C, pH 7.0, and 0–1% NaCl. Results of 16S rRNA gene sequence analyses indicated a close relationship of this isolate to Acinetobacter calcoaceticus (97.8% similarity for strain DSM 30006^T). It also exhibited 94.4–97.8% 16S rRNA gene sequence similarities to the validly published Acinetobacter species. The value for DNA-DNA hybridization between strain 5YN5-8^T and other members of the genus Acinetobacter ranged from 16 to 28%. Predominant cellular fatty acids were C_18:1 ω9c, summed feature 4 containing C_15:0 iso 2-OH and/or C_16:1 ω7c, and C_16:0. The DNA G+C content was 43.9 mol%. Phylogenetic, phenotypic, and chemotaxonomic data accumulated in this study revealed that the isolate could be classified in a novel species of the genus Acinetobacter. The name Acinetobacter brisouii sp. nov. is proposed for the novel species, with 5YN5-8^T (=KACC 11602^T = DSM 18516^T) as the type strain.     

Identification by gas chromatography and mass spectrometry of lipids from the rat Harderian gland

Lipids from rat Harderian glands were extracted with ethyl acetate, hydrolysed with base and examined by gas chromatography (GC) and gas chromatography—mass spectrometry (GC—MS) as trimethylsilyl (TMS), [²H₉]TMS, methyl ester—TMS, picolinyl, nicotinate and nicotinylidene derivatives. The latter three derivatives were used to reveal the structures of the alkyl chains of fatty acids, alcohols and glycerol ethers, respectively. Forty-eight compounds were identified, representing about 97% of the total extracted lipids as measured by GC peak areas. The major constituents were fatty acids with chain lengths from 12 to 22 carbon atoms (mainly C₁₈ and C₂₀) and fatty alcohols (C₁₆ to C₂₆) derived from wax esters. Most of these acids and alcohols were unsaturated in the ω-7 position and were accompanied by smaller amounts of the saturated and ω-5 monounsaturated analogues. Glycerol ethers were also identified for the first time in this secretion; the ether chains contained from 14 to 19 carbon atoms (mainly 16) and were straight-chain saturated, unsaturated (ω-5 and ω-7) and branched (iso). The only sterol found was cholesterol amounting to 1.24% of the total extract.     

Transformation of sterols byMycobacterium vaccae: effect of lecithin on the permeability of cell envelopes to sterols

An enhancement of Β-sitosterol transformation to androstendione byMycobacterium vaccae observed in medium containing egg-yolk lecithin, was associated with the incorporation of a considerable amount of lecithin into the cell envelope lipids. By GC/MS measurements, fatty acids ranging from 14 to 22 carbon atoms were identified in the lipids removed from the cells by organic solvents. Octadecenoic (18:1), 2-methyl-octadecenoic (2-Me 18:1), and hexadecanoic (16:0) acids were the major components of the lipid preparation obtained from both the control cells, and the cells grown in lecithin-containing medium. However, in the fatty acid pattern of the latter a distinct increase in the C_18:1 component, concomitant with the decrease in the 2-Me 18:1 fatty acid was demonstrated. The C₁₆ fatty acid fraction also showed a higher content of methyl-branched components in the control cell preparation. The enrichment in unsaturated fatty acids increases fluidity of lipids, whereas the decrease in methyl-branched fatty acids may affect the conformation of the surface lipidic components, which may result in enhanced sterol penetration through the cell wall barrier in the presence of lecithin.     

<Emphasis Type="Italic">Halomonas sediminis</Emphasis> sp. nov., a new halophilic bacterium isolated from salt-lake sediment in China

A novel Gram-negative, slightly halophilic, catalase- and oxidase-positive, obligately aerobic bacterium, strain YIM-C248^T, was isolated from a sediment sample collected from a salt-lake in the Qaidam Basin in Qinghai, north-west China. Cells were non-sporulating short rods, occurring singly or as doublets, motile with peritrichous flagella. Growth occurred with 1–15% (w/v) NaCl [optimum 2–4% (w/v) NaCl], at pH 6.0–10.0 (optimum pH 7.5) and at 4–35°C (optimum 25–30°C). The major cellular fatty acids were C_18:1 ω7c, C_12:0 3-OH, cyclo C_19:0 ω8c, C_16:0 and C_16:1. The predominant respiratory quinone was Q-9 and the genomic DNA G + C content was 58.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM-C248^T should be assigned to the genus Halomonas. The sequence similarities between the isolate and the type strains of members of the genus Halomonas were in the range of 92.5–97.5%. The combination of phylogenetic analysis, DNA–DNA hybridization data, phenotypic characteristics and chemotaxonomic differences supported the view that strain YIM-C248^T represents a new species of the genus Halomonas, for which the name Halomonas sediminis sp. nov. is proposed, with YIM-C248^T (=CCTCC AA 207031 = KCTC 22167) as the type strain. The GenBank/EMBL/DBBJ accession number for the 16S rRNA gene sequence of strain YIM-C248^T is EU135707.     

Growth, natural relationships, cellular fatty acids and metabolic adaptation of sulfate-reducing bacteria that utilize long-chain alkanes under anoxic conditions

Natural relationships, improvement of anaerobic growth on hydrocarbons, and properties that may provide clues to an understanding of oxygen-independent alkane metabolism were studied with two mesophilic sulfate-reducing bacteria, strains Hxd3 and Pnd3. Strain Hxd3 had been formerly isolated from an oil tank; strain Pnd3 was isolated from marine sediment. Strains Hxd3 and Pnd3 grew under strictly anoxic conditions on n-alkanes in the range of C₁₂–C₂₀ and C₁₄–C₁₇, respectively, reducing sulfate to sulfide. Both strains shared 90% 16 S rRNA sequence similarity and clustered with classified species of completely oxidizing, sulfate-reducing bacteria within the δ-subclass of Proteobacteria. Anaerobic growth on alkanes was stimulated by α-cyclodextrin, which served as a non-degradable carrier for the hydrophobic substrate. Cells of strain Hxd3 grown on hydrocarbons and α-cyclodextrin were used to study the composition of cellular fatty acids and in vivo activities. When strain Hxd3 was grown on hexadecane (C₁₆H₃₄), cellular fatty acids with C-odd chains were dominant. Vice versa, cultures grown on heptadecane (C₁₇H₃₆) contained mainly fatty acids with C-even chains. In contrast, during growth on 1-alkenes or fatty acids, a C-even substrate yielded C-even fatty acids, and a C-odd substrate yielded C-odd fatty acids. These results suggest that anaerobic degradation of alkanes by strain Hxd3 does not occur via a desaturation to the corresponding 1-alkenes, a hypothetical reaction formerly discussed in the literature. Rather an alteration of the carbon chain by a C-odd carbon unit is likely to occur during activation; one hypothetical reaction is a terminal addition of a C₁ unit. In contrast, fatty acid analyses of strain Pnd3 after growth on alkanes did not indicate an alteration of the carbon chain by a C-odd carbon unit, suggesting that the initial reaction differed from that in strain Hxd3. When hexadecane-grown cells of strain Hxd3 were resuspended in medium with 1-hexadecene, an adaptation period of 2 days was observed. Also this result is not in favor of an anaerobic alkane degradation via the corresponding 1-alkene. Received: 25 June 1998 / Accepted: 29 July 1998     

<Emphasis Type="Italic">Henriciella marina</Emphasis> gen. nov., sp. nov., a novel member of the family <Emphasis Type="Italic">Hyphomonadaceae</Emphasis> isolated from the East Sea

A bacterial strain, designated Iso4^T, was isolated from the East Sea of Korea and was subjected to a poly-phasic taxonomy study including phenotypic and chemotaxonomic characteristics as well as 16S rRNA gene sequence analysis. Cells of the strain were Gram-negative, motile, non-budding, non-stalked, and strictly aerobic. Strain Iso4^T grew optimally at 20°C in the presence of 1∼2% (w/v) NaCl and at pH 6.9∼7.6. The major respiratory quinone was Q-10 and the major cellular fatty acids were C_18:1 ω7c (53.5%), C_17:1 ω5c (11.7%), C_17:1 ω6c (8.1%), C_16:0 (7.8%), C_17:0 (4.8%), C_15:0 (2.9%), and C_16:1 ω5c (2.2%). The DNA G+C content of strain Iso4^T was 56.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Iso4^T formed a monophyletic clade in the family Hyphomonadaceae, supported by high bootstrap value and was most closely related to the genus Hyphomonas (92∼94%), a member of marine bacteria in the family. The phenotypic, genotypic, and chemotaxonomic evidences also suggest strain Iso4^T represents a novel genus and species in the family Hyphomonadaceae, for which the name Henriciella gen. nov., sp. nov. is proposed. The type strain is Iso4^T (=KCTC 12513^T =DSM 19595^T =JCM 15116^T).     

Lipid storage compounds in marine bacteria

Forty psychrophile or psychrotrophic crude-oil-utilizing marine bacteria were investigated for their ability to accumulate lipid storage compounds in the cytoplasm during cultivation under nitrogen-limiting conditions. Most of them (73%) were able to accumulate specialized lipids like polyhydroxyalkanoic acids (PHA) while other lipids such as wax esters occurred in two isolates. Accumulation of PHA occurred predominantly at low temperatures (4–20 °C) as demonstrated for three isolates. Electron microscopy revealed polyphosphate inclusions occurring in two isolates in addition to PHA. Cells of the isolate Acinetobacter sp. 211 were able to synthesize and accumulate lipid inclusions during growth on acetate, ethanol, olive oil, hexadecanol and heptadecane. The composition of the lipid inclusions depended on the compounds provided as carbon source. Wax esters and acylglycerols occurred mainly during the cultivation on olive oil; in contrast, wax esters and free alcohols occurred during cultivation on hexadecanol. Total fatty acids in cells of the Acinetobacter sp. 211 amounted to 25% of the cellular dry weight in olive-oil-grown cells. Palmitic acid was the main fatty acid in the lipids when the cells were cultivated on acetate or ethanol (44% and 32% of total fatty acids respectively). In contrast, fatty acids occurring in the lipids during cultivation on hexadecanol, heptadecane or olive oil were related to the carbon source. The fatty acids present in the accumulated lipids consisted predominantly of saturated and unsaturated straight-chain fatty acids with a chain length ranging from 12 to 18 carbon atoms. Analysis of the lipid-granule-associated proteins in cells of Acinetobacter sp. 211 revealed a protein of 39 kDa as the predominant protein species. Received: 2 July 1996 / Received revision: 3 September 1996 / Accepted: 28 September 1996     

Biodegradation of commercial linear alkyl benzenes byNocardia amarae

Laboratory degradation studies of two indigeneously produced linear alkyl benzenes byNocardia amarae MB-11 isolated from soil showed an overall degradation of linear alkyl benzenes isomers to the extent of 57–70%. Degradation of 2-phenyl isomers of linear alkyl benzenes was complete and faster than that of other phenyl position (C3–C7) isomers which were degraded to the extent of 40–72% only. Length of alkyl side chains (C₁₀–C₁₄) had little or no impact on the degradation pattern. Major metabolities detected were 2-, 3-and 4-phenyl butyric acids, phenyl acetic acid and cis, cis-muconic acid. Minor metabolites weretrans-cinnamic acid, 4-phenyl 3-butenoic acid and 3-phenyl pentanoic acid along with two unidentified hydroxy acids. On the basis of the formation pattern of these metabolities, three catabolic pathways of linear alkyl benzenes isomers inNocardia amarae MB-11 were postulated. All the phenyl position (C2–C7) isomers of C₁₀, C₁₂, and C₁₄ linear alkyl benzenes along with 3-phenyl and 5-phenyl isomers of C₁₁ and C₁₃ linear alkyl benzenes were degraded viacis,cis-muconic acid pathway. Other phenyl position isomers of C₁₁ and C₁₃ linear alkyl benzenes with phenyl substitution at even number carbon atoms were principally degraded via phenyl acetic acid pathway whiletrans-cinnamic acid formation provided a minor pathway     

Assimilation of hydrocarbons

When cultivating different yeast genera on the mixture of C₁₁−C₂₃ n-alkanes with predominant C₁₆ and C₁₇ content C₁₆ and C₁₇ fatty acids predominated in the synthetized cell fat. Besides these C_11∶0, C_15∶0 and C_18∶1 fatty acids were also present in higher quantities in all strains tested. This conclusion is in agreement with results of the residualn-alkanes estimation where during the fermentation most of the C₁₆ and C₁₇ hydrocarbons decreased from the original hydrocarbon mixture. From these experiments it can be provisionally concluded that the qualitative composition of the cell fat is not dependent on the yeast strain investigated, the amount of fat on the dry weight basis depends on the strain.     

Characterization of the hydroxy fatty acid content ofBasidiomycotina

Fatty acids (FA) of nine fungal species belonging to the subphylumBasidiomycotina were identified by using capillary GC-MS, MS and HPLC. The identified fatty acids included 45 saturated (iso-, anteiso-, and 19 hydroxy acids) and 42 monoenoic acids (including 14 hydroxy acids); dienes and polyenes were represented by 13 fatty acids. The proportion of hydroxy acids in the total fatty acids in the fungal species ranged from 4.3 to 10.2%. Very long-chain fatty acids (C₂₄-C₃₀) were also determined. Four fatty acids 16:0 (8.8–14.3%), 18:1(11) (3.9–14.9%), 18:1(9) (7.7–19.0%) and 18:2(6) (7.6–19.4%), were found as major acids. Of the identified acids, 17 were detected inBasidiomycotina for the first time.     

Effect of cell lipid composition on the formation of nonspecific antibiotic resistance in alkanotrophic rhodococci

The antibiotic resistance and lipid composition of rhodococci grown in rich organic media with gaseous or liquidn-alkanes were studied. Hydrocarbon-grown rhodococci exhibited an increased resistance to a wide range of antibiotics (aminoglycosides, linkosamides, macrolides, β-lactams, and aromatic compounds). The enhanced antibiotic resistance of rhodococci grown onn-alkanes correlated with an increased content of total cell lipids (up to 14–28%) and saturated straight-chain fatty acids (C_16:0, C_18:0, C_21:0) and was accompanied by the appearance of cardiolipin and phosphatidylglycerol in cells. These lipid compounds are supposed to promote the formation of nonspecific antibiotic resistance in rhodococci by decreasing the permeability of their cell envelope to antibiotics.     

<Emphasis Type="Italic">Singulispaera mucilagenosa</Emphasis> sp. nov., a novel acid-tolerant representative of the order <Emphasis Type="Italic">Planctomycetales</Emphasis>

Two novel strains of budding bacteria, Z-0071^T and Z-0072, were isolated from dystrophic humified waters formed by xylotrophic fungi in the course of spruce wood degradation. The cells of both strains are coccoid (0.95–1.80 μm), nonmotile, single or arranged in pairs. The cells have a complex system of intracellular membranes and are covered with fimbriae and surrounded by a mucous capsule up to 0.3 μm thick. Both strains are aerobic organoheterotrophic, mesophilic, and acid-tolerant microorganisms that are able to grow under microaerobic conditions. They utilize N-acetyl-glucosamine, carbohydrates, and lactate as growth substrates. The strains grow in a pH range of 4.0–7.5 with an optimum at 6.0–6.5. The temperature range for growth is 4–30°C, with an optimum at 25–28°C. Strains Z-0071^T and Z-0072, inhabitants of dystrophic low-mineral waters, are NaCl-sensitive: the NaCl content in the media above 0.5 g/l inhibited growth. The main fatty acids of strains Z-0071^T and Z-0072 are C_16:0, C_18:1ω9c, and C_{18:2ω9c, 12c}. The DNA G + C base content is 51.2–51.7 mol %. The sequences of the 16S rRNA gene fragments (1310 bp) of strains Z-0071^T and Z-0072 were found to be identical. The obtained sequences showed a 94.3% similarity with the sequences of the type strain of the most closely related species Singulisphaera acidiphila MOB10≅T. The phenotypic and phylogenetic properties of strains Z-0071^T and Z-0072 support classification of these strains within the genus Singulisphaera as a new species Singulisphaera mucilagenosa sp. nov., with the type strain Z-0071^T (VKM B-2626).