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 ).     

Antibiofilm activity of an exopolysaccharide from marine bacterium Vibrio sp. QY101

Bacterial exopolysaccharides have always been suggested to play crucial roles in the bacterial initial adhesion and the development of complex architecture in the later stages of bacterial biofilm formation. However, Escherichia coli group II capsular polysaccharide was characterized to exert broad-spectrum biofilm inhibition activity. In this study, we firstly reported that a bacterial exopolysaccharide (A101) not only inhibits biofilm formation of many bacteria but also disrupts established biofilm of some strains. A101 with an average molecular weight of up to 546 KDa, was isolated and purified from the culture supernatant of the marine bacterium Vibrio sp. QY101 by ethanol precipitation, iron-exchange chromatography and gel filtration chromatography. High performance liquid chromatography traces of the hydrolyzed polysaccharides showed that A101 is primarily consisted of galacturonic acid, glucuronic acid, rhamnose and glucosamine. A101 was demonstrated to inhibit biofilm formation by a wide range of Gram-negative and Gram-positive bacteria without antibacterial activity. Furthermore, A101 displayed a significant disruption on the established biofilm produced by Pseudomonas aeruginosa, but not by Staphylococcus aureus. Importantly, A101 increased the aminoglycosides antibiotics' capability of killing P. aeruginosa biofilm. Cell primary attachment to surfaces and intercellular aggregates assays suggested that A101 inhibited cell aggregates of both P. aeruginosa and S. aureus, while the cell-surface interactions inhibition only occurred in S. aureus, and the pre-formed cell aggregates dispersion induced by A101 only occurred in P. aeruginosa. Taken together, these data identify the antibiofilm activity of A101, which may make it potential in the design of new therapeutic strategies for bacterial biofilm-associated infections and limiting biofilm formation on medical indwelling devices. The found of A101 antibiofilm activity may also promote a new recognition about the functions of bacterial exopolysaccharides.     

Massilia sp. BS-1, a novel violacein-producing bacterium isolated from soil

A novel bacterium, Massilia sp. BS-1, producing violacein and deoxyviolacein was isolated from a soil sample collected from Akita Prefecture, Japan. The 16S ribosomal DNA of strain BS-1 displayed 93% homology with its nearest violacein-producing neighbor, Janthinobacterium lividum. Strain BS-1 grew well in a synthetic medium, but required both L-tryptophan and a small amount of L-histidine to produce violacein.     

Flocculation behavior and mechanism of an exopolysaccharide from the deep-sea psychrophilic bacterium Pseudoalteromonas sp. SM9913

Flocculation behavior and mechanism of the exopolysaccharide secreted by Pseudoalteromonas sp. SM9913 (EPS SM9913), a psychrophilic bacterium isolated from 1855m deep-sea sediment, has been studied in this paper. EPS SM9913 showed a peak flocculating activity of 49.3 in 1g/L kaolin suspension with 4.55mmol/L CaCl2 and the optimum pH range of 5-8. It appears that the flocculating activity of EPS SM9913 was stimulated by Ca2+ and Fe2+. This study found that EPS SM9913 showed a better flocculation performance than Al2(SO4)3 at salinity of 5-100 per thousand or temperatures of 5-15 degrees C. In addition, this EPS was effective to flocculate several other suspended solids. The measured zeta-potentials, the size of flocs formed during the flocculation process and the surface profile of flocs revealed by scan electron micrograph suggest that bridging is the main flocculation mechanism of the studied EPS. Deacetylation of EPS SM9913 resulted in a significant decrease in its flocculating activity indicating that the large number of acetyl groups in EPS SM9913 played an important role in its flocculation performance.     

An aerobic formate-utilizing bacterium,Cupriavidus sp., isolated from activated sludge of wastewater treatment

An aerobic formate-assimilating bacterium, denoted as strain FAB, was newly isolated from activated sludge of wastewater treatment. Phylogenetic analysis based on 16S rDNA sequence assigned the isolate to the genus Cupriavidus. Scanning electron micrography revealed that this bacterium has a coccal morphology, and from some physiological assays, the bacterium was characterized to be Gram-negative, nitrate-reduction-positive and catalase-positive. In addition to formate, strain FAB was able to utilize fructose, acetate or pyruvate as a preferred carbon source. Compared with a close relative, Cupriavidus necator, our isolate exhibited a greater growth rate on formate under an aerobic condition.     

Paenibacillus swuensis sp. nov., a bacterium isolated from soil

Strain DY6^T, a Gram-positive endospore-forming motile rod-shaped bacterium, was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analyses based on the 16S rRNA gene sequence of strain DY6^T revealed that strain DY6^T belongs to the genus Paenibacillus in the family Paenibacillaceae in the class Bacilli. The highest degree of sequence similarities of strain DY6^T were found with Paenibacillus gansuensis B518^T (97.9%), P. chitinolyticus IFO 15660^T (95.3%), P. chinjuensis WN9T (94.7%), and P. rigui WPCB173^T (94.7%). Chemotaxonomic data revealed that the predominant fatty acids were anteiso-C_15:0 (38.7%) and C_16:0 (18.0%). A complex polar lipid profile consisted of major amounts of diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. The predominant respiratory quinone was MK-7. Based on these phylogenetic, chemotaxonomic, and phenotypic data, strain DY6^T (=KCTC 33026^T =JCM 18491^T) should be classified as a type strain of a novel species, for which the name Paenibacillus swuensis sp. nov. is proposed.     

Microlunatus terrae sp. nov., a bacterium isolated from soil

Strain BS6(T), a Gram-positive non-motile bacterium, was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that strain BS6T belonged to the family Propionibacteriaceae in the class Actinobacteria. Strain BS6(T) showed the highest 16S rRNA gene sequence similarity with Microlunatus soli CC-012602(T) (98.6%) and high sequence similarities with Microlunatus species (94.5-98.6%). Chemotaxonomic data revealed that the predominant fatty acids were anteiso-C(17:0), anteiso-C(15:0), summed feature 8 (C(18:1) ω7c/ω6c), and iso-C(16:0). The cell wall peptidoglycan contained (LL)-diaminopimelic acid, and the major polar lipids were diphosphatidylglycerol, and phosphatidylglycerol. Based on these data, BS6(T) (=KCTC 19858(T) =JCM 17661(T) =CCARM 9244(T) =KEMC 9004-079(T)) should be classified as a type strain of a novel species, for which the name Microlunatus terrae sp. nov. is proposed.     

Pigmentiphaga soli sp. nov., a bacterium isolated from soil

Strain BS12^T, a Gram-negative motile bacterium, was isolated from soil in South Korea and characterized to determine its taxonomic position. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the strain belonged to the family Alcaligenaceae in the class Betaproteobacteria. The highest degree of sequence similarities of strain BS12^T were found with Pigmentiphaga litoralis JSM 061001^T (98.3%), Pigmentiphaga daeguensis K110^T (98.2%), and Pigmentiphaga kullae K24^T (98.1%). Chemotaxonomic data revealed that strain BS12^T possessed ubiquinone-8, which is common in the family Alcaligenaceae, and the predominant fatty acids were C_16:0, C_17:0 cyclo, summed feature 3 (C_16:1 ω6c/ω7c), and summed feature 8 (C_18:1 ω6c/ω7c). The major polar lipids of strain BS12^T were phosphatidylethanolamine and phosphatidylglycerol. Based on these data, BS12^T (=KCTC 23577^T =JCM 17666^T =KEMB 9004-082^T) should be classified as a type strain of a novel species, for which the name Pigmentiphaga soli sp. nov. is proposed.     

<Emphasis Type="Italic">Thauera sinica</Emphasis> sp. nov., a phenol derivative-degrading bacterium isolated from activated sludge

A bacterial strain, K11^T, capable of degrading phenol derivatives was isolated from activated sludge of a sewage treatment plant in China. This strain, which can degrade more than ten phenol derivatives, was identified as a Gram-stain negative, rod-shaped, asporogenous, facultative anaerobic bacterium with a polar flagellum. The strain was found to grow in tryptic soy broth in the presence of 0–2.5% (w/v) NaCl (optimum 0–1%), at 4–43 °C (optimum 30–35 °C) and pH 4.5–10.5 (optimum 7.5–8). Comparative analysis of nearly full-length 16S rRNA gene sequences showed that this strain belongs to the genus Thauera. The 16S rRNA gene sequence was found to show high similarity (97.5%) to that of Thauera chlorobenzoica 3CB-1^T, with lesser similarity to other recognised Thauera strains. The G+C content of the DNA of the strain was determined to be 67.8 mol%. The DNA–DNA hybridization value between K11^T and Thauera aromatica DSM6984^T was 10.4 ± 4.5%. The genomic OrthoANI values of K11^T with the other nine type strains of genus Thauera were less than 81.1%. Chemotaxonomic analysis of strain K11^T revealed that Q-8 is the predominant quinone; the polar lipids contain phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and five uncharacterised lipids; the major cellular fatty acid was identified as summed feature 3 (C_16:1 ω7c and/or iso-C_15:0 2-OH; 45.9%), followed by C_16:0 (20.5%) and C_18:1 ω7c (15.8%). Based on the phenotypic and phylogenetic evidence, DNA–DNA hybridisation, OrthoANI, chemotaxonomic analysis and results of the physiological and biochemical tests, a new species named Thauera sinica sp. nov. is proposed with strain K11^T (= CGMCC 1.15731^T = KACC 19216^T) designated as the type strain.     

Methylobacterium soli sp. nov. a methanol-utilizing bacterium isolated from the forest soil

A Gram-negative, pink-pigmented, non-spore-forming rod shaped, methanol-utilizing bacterium, strain YIM 48816(T), was isolated from forest soil collected from Sichuan province, China. Strain YIM 48816(T) can grow at 4-37 °C, pH 5.0-7.0 and 0% NaCl (w/v). Based on 16S rRNA gene sequence similarity studies, it belonged to the genus Methylobacterium, and formed a phyletic line. The 16S rRNA gene sequence similarities were 96.2% to Methylobacterium mesophilicum DSM 1708(T) and 96.0% to Methylobacterium brachiatum DSM 19569(T), and the phylogenetic similarities to all other Methylobacterium species with validly published names were less than 96.0%. The major menaquinones detected were Q-10 (97.14%) and Q-9 (2.86%). The major fatty acids were C18:1 ω7c (80.84%). The DNA G + C content was 66.2 mol%. It is apparent from the genotypic and phenotypic data that strain YIM 48816(T) belongs to a novel species of the genus Methylobacterium, for which the name Methylobacterium soli sp. nov. is proposed. The type strain is YIM 48816(T) (CCTCC AA 208027(T) = KCTC 22810(T)).     

Methylobacterium sp. isolated from a Finnish paper machine produces highly pyruvated galactan exopolysaccharide

The slime-forming bacterium Methylobacterium sp. was isolated from a Finnish paper machine and its exopolysaccharide (EPS) was produced on laboratory scale. Sugar compositional analysis revealed a 100% galactan (EPS). However, FT-IR showed a very strong peak at 1611 cm(-1) showing the presence of pyruvate. Analysis of the pyruvate content revealed that, based on the sugar composition, the EPS consists of a trisaccharide repeating unit consisting of D-galactopyranose and [4,6-O-(1-carboxyethylidene)]-D-galactopyranose with a molar ratio of 1:2, respectively. Both linkage analysis and 2D homo- and heteronuclear 1H and 13C NMR spectroscopy revealed the following repeating unit: -->3)-[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)[4,6-O-(1-carboxyethylidene)]-alpha-D-Galp-(1-->3)-alpha-D-Galp-(1-->. By enrichment cultures from various ground and compost heap samples a polysaccharide-degrading culture was obtained that produced an endo acting enzyme able to degrade the EPS described. The enzyme hydrolysed the EPS to a large extent, releasing oligomers that mainly consisted out of two repeating units.