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Strain DRJ-4 T was isolated from forest soil of a low-altitude mountain and was taxonomically characterized by a polyphasic approach. This strain was yellow-colored, Gram-stain-negative, strictly aerobic, motile, non-sporulating, catalase-positive, oxidase-negative, and rod-shaped. Strain DRJ-4 T was able to grow at 20-42 °C, pH 6.5-10.0, and 0-1.0% (w/v) NaCl concentration. Based on the 16S rRNA gene sequence analysis, strain DRJ-4 T formed a distinct lineage within the members of the family Sphingomonadaceae of the phylum Proteobacteria and moderately related to Sphingomonas faucium E62-3 T (96.67% sequence similarity), 'Sphingosinicella ginsenosidimutans' BS11 (96.45% sequence similarity), Sphingosinicella vermicomposti YC7378 T (96.27% sequence similarity), and Sphingobium boeckii 469 T (95.82% sequence similarity). The sole respiratory quinone was ubiquinone Q-10 and the major polyamine was homospermidine. The polar lipid profile revealed the presence of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidylmonomethylethanolamine, and sphingoglycolipid. The predominant fatty acids of strain DRJ-4 T were summed feature 8 (C 18:1 ω7c and/or C 18:1 ω6c), summed feature 3 (C 16:1 ω7c and/or C 16:1 ω6c), C 16:0 , and C 17:1 ω6c. The genomic DNA G + C was 64.0 mol %. On the basis of phenotypic, genotypic, and phylogenetic analysis, strain DRJ-4 T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas montis sp. nov. is proposed. The type strain of Sphingomonas montis is DRJ-4 T (= KEMB 9005-708 T  = NBRC 113142 T ).

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, designated X1(T), was isolated from the permafrost region of Qilian Mountains in northwest of China. Phylogenetic analyses of 16S rRNA gene sequence revealed that strain X1(T) was a member of the genus Sphingomonas and shared the highest 16S rRNA gene sequence similarity with Sphingomonas oligophenolica JCM 12082(T) (96.9%), followed by Sphingomonas glacialis CGMCC 1.8957(T) (96.7%) and Sphingomonas alpina DSM 22537(T) (96.4%). Strain X1(T) was able to grow at 15-30 °C, pH 6.0-10.0 and with 0-0.3% NaCl (w/v). The DNA G+C content of the isolate was 64.8 mol%. Strain X1(T)-contained Q-10 as the dominant ubiquinone and C(18:1)ω7c, C(16:1)ω7c, C(16:0) and C(14:0) 2-OH as the dominant fatty acids. The polar lipid profile of strain XI(T)-contained sphingoglycolipid, phosphatidylglycerol, phosphatidylethanolamine, one unidentified glycolipid and two unidentified phospholipid. Due to the phenotypic and genetic distinctiveness and other characteristic studied in this article, we consider X1(T) as a novel species of the genus Sphingomonas and propose to name it Sphingomonas qilianensis sp. nov. The type strain is X1(T) (=CGMCC 1.15349(T) = KCTC 42862(T)).

A type II arabinogalactan-degrading enzyme, termed Exo-1,3-Gal, was purified to homogeneity from the culture filtrate of Sphingomonas sp. 24T. It has an apparent molecular mass of 48 kDa by SDS-PAGE. Exo-1,3-Gal was stable from pH 3 to 10 and at temperatures up to 40 °C. The optimum pH and temperature for enzyme activity were pH 6 to 7 and 50 °C, respectively. Galactose was released from β-1,3-D: -galactan and β-1,3-D: -galactooligosaccharides by the action of Exo-1,3-Gal, indicating that the enzyme was an exo-β-1,3-D: -galactanase. Analysis of the reaction products of β-1,3-galactotriose by high-performance anion-exchange chromatography revealed that the enzyme hydrolyzed the substrate in a non-processive mode. Exo-1,3-Gal bypassed the branching points of β-1,3-galactan backbones in larch wood arabinogalactan (LWAG) to produce mainly galactose, β-1,6-galactobiose, and unidentified oligosaccharides 1 and 2 with the molar ratios of 7:19:62:12. Oligosaccharides 1 and 2 were enzymatically determined to be β-1,6-galactotriose and β-1,6-galactotriose substituted with a single arabinofuranose residue, respectively. The ratio of side chains enzymatically released from LWAG was in good agreement with the postulated structure of the polysaccharide previously determined by chemical methods.

In a water-organic solvent, two-phase conversion system, CoQ(10) could be produced directly from solanesol and para-hydroxybenzoic acid (PHB) by free cells of Sphingomonas sp. ZUTE03 and CoQ(10) concentration in the organic solvent phase was significantly higher than that in the cell. CoQ(10) yield reached a maximal value of 60.8 mg l(-1) in the organic phase and 40.6 mg g(-1)-DCW after 8 h. CoQ(10) also could be produced by gel-entrapped cells in the two-phase conversion system. Soybean oil and hexane were found to be key substances for CoQ(10) production by gel-entrapped cells of Sphingomonas sp. ZUTE03. Soybean oil might improve the release of CoQ10 from the gel-entrapped cells while hexane was the suitable solvent to extract CoQ(10) from the mixed phase of aqueous and organic. The gel-entrapped cells could be re-used to produce CoQ(10) by a repeated-batch culture. After 15 repeats, the yield of CoQ(10) kept at a high level of more than 40 mg l(-1). After 8 h conversion under optimized precursor's concentration, CoQ(10) yield of gel-trapped cells reached 52.2 mg l(-1) with a molar conversion rate of 91% and 89.6% (on PHB and solanesol, respectively). This is the first report on enhanced production of CoQ(10) in a two-phase conversion system by gel-entrapped cells of Sphingomonas sp. ZUTE03.

Sphingomonas sp. strain LH128 was isolated from a polycyclic aromatic hydrocarbon (PAH)-contaminated soil using phenanthrene as the sole source of carbon and energy. A dioxygenase complex, phnA1fA2f, encoding the alpha and beta subunit of a terminal dioxygenase responsible for the initial attack on PAHs, was identified and isolated from this strain. PhnA1f showed 98%, 78%, and 78% identity to the alpha subunit of PAH dioxygenase from Novosphingobium aromaticivorans strain F199, Sphingomonas sp. strain CHY-1, and Sphingobium yanoikuyae strain B1, respectively. When overexpressed in Escherichia coli, PhnA1fA2f was able to oxidize low-molecular-weight PAHs, chlorinated biphenyls, dibenzo-p-dioxin, and the high-molecular-weight PAHs benz[a]anthracene, chrysene, and pyrene. The action of PhnA1fA2f on benz[a]anthracene produced two benz[a]anthracene dihydrodiols.

Bacterial exopolysaccharides (EPS) are products of biotechnology that are of high interest due to their rheological properties. This is the case of sphingans, a group of structurally related EPS secreted by members of the genus Sphingomonas. Among these, gellan is a multifunctional gelling agent produced in high yields by the non-pathogenic strain Sphingomonas elodea ATCC 31461. In its native form, gellan is a linear anionic EPS based on a tetrasaccharide repeat unit composed of two molecules of D: -glucose, one of L: -rhamnose and one of D: -glucuronic acid. The native gellan is partially esterified with acyl substituents (1 mol of glycerate and 0.5 mol of acetate) per repeat unit. Gellan has unique characteristics and has many applications, particularly in the food, pharmaceutical, and biomedical fields. This review summarizes current knowledge on the structure and properties of gellan and provides details about the biosynthesis of this exopolysaccharide. In addition, a highlight of the importance of gellan in industrial and medicinal applications is given.

Members of the bacterial genus Sphingomonas are known to produce highly viscous polysaccharides in solution. The exopolysaccharide PS-EDIV was produced by Sphingomonas pituitosa strain DSM 13101, purified using centrifugation, and precipitation and its structure was elucidated by 1D and 2D NMR techniques and chemical microderivatization combined with various mass spectrometric techniques. The following repeating unit of the polysaccharide could be identified: [Formula: see text]. In addition, the polysaccharide also contains acetyl and glyceryl groups whose exact positions were not determined. PS-EDIV is similar in structure to a known exopolysaccharide but differs in being the first bacterial polysaccharide in which two different glucuronic acids are combined. It caused a high viscosity of the culture broth after cultivation for 48 h, although a gelation was not observed.