Caenibacterium thermophilum is a later synonym of Schlegelella thermodepolymerans

Schlegelella koreensis sp. nov., isolated from evaporator core of automobile air conditioning system

A white-coloured, aerobic, and rod-shaped bacterium, designated strain ID0723^T was isolated from evaporator core of automobile air conditioning system. The strain was Gram-stain-negative, catalase positive, oxidase negative, and grew at pH 5.5-9.5, at temperature 18-37 °C, and at 0-2.0% (w/v) NaCl concentration. The phylogenetic analysis and 16S rRNA gene sequence data revealed that the strain ID0723^T was affiliated to the genus Schlegelella, with the closest phylogenetic member being Schlegelella brevitalea DSM 7029 ^T (98.1% sequence similarity). The chemotaxonomic features of strain ID0723^T were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine as the main polar lipids; Q-8 as an only ubiquinone; and summed feature 3 (C_16:1ω7c and/or C_{16: 1}ω6c), C_16:0, and summed feature 8 (C_18:1ω7c/or C_18:1ω6c) as the major fatty acids. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization values between strain ID0723^T and S. brevitalea DSM 7029 ^T were 74.8% and 20.0%, respectively, which were below the cut-off values of 95% and 70%, respectively. The DNA G + C content was 69.9 mol%. The polyphasic taxonomic data clearly indicated that strain ID0723^T represents a novel species in the genus Schlegelella for which the name Schlegelella koreensis sp. nov. is proposed, with the type strain ID0723^T (= KCTC 72731 ^T = NBRC 114611 ^T).

Limnohabitans curvus gen. nov., sp. nov., a planktonic bacterium isolated from a freshwater lake

A chemo-organotrophic, aerobic, facultatively anaerobic, non-motile strain, MWH-C5(T), isolated from the water column of the oligomesotrophic Lake Mondsee (Austria), was characterized phenotypically, phylogenetically and chemotaxonomically. The predominant fatty acids of the strain were C(16 : 1)omega7c/omega6c, C(16 : 0), C(12 : 1) and C(8 : 0)-3OH, the major quinone was ubiquinone Q-8 and the G+C content of the DNA of the strain was 55.5 mol%. 16S rRNA gene similarity to the closest related type strains was 96.6 % (Curvibacter delicatus LMG 4328(T)) and 95.7 % (Rhodoferax fermentans FR3(T)). Phylogenetic analysis of 16S rRNA gene sequences revealed the affiliation of the strain with the family Comamonadaceae (Betaproteobacteria); however, the phylogenetic position of the strain did not support an affiliation to any previously described genus within this family. A family-wide comparison of traits revealed that the strain possesses a unique combination of DNA G+C content, major fatty acids and major 3-hydroxy fatty acid. Furthermore, the strain differs in several traits from the closest related genera. Based on the phylogeny of the strain and differences from closely related genera, we propose to establish the new genus and species Limnohabitans curvus gen. nov., sp. nov. to accommodate this strain. The type strain of Limnohabitans curvus is MWH-C5(T) (=DSM 21645(T) =CCUG 56720(T)). The type strain is closely related to a large number of uncultured bacteria detected by cultivation-independent methods in various freshwater systems.

Amplified ribosomal DNA restriction analysis of free-living bacteria present in the headbox of a Canadian paper machine

The headbox water is the main source of bacterial contamination of paper machines. Identification of these bacterial contaminants could be an asset in developing specific control methods. An amplified ribosomal DNA restriction analysis (ARDRA) was carried out to characterize the bacterial communities associated with the headbox water of a paper machine in a Canadian mill in February and July 2006. Eight bacterial genera were identified as the main colonizers present in the headbox water. The genus Meiothermus appeared to be the dominant bacterial group in the Canadian paper machine. Some variation was observed between the February and July clone libraries. Bacterial genera such as Chelatococcus and Hydrogenophilus were only detected in February or in July, respectively. Furthermore, the proportion of Tepidimonas clones in the libraries was higher in July than in February. The metabolic profile of the February and July communities, determined using Biolog EcoPlates, also suggested that temporal variation occurred within the bacterial populations that colonized the headbox of the paper machine.

Thermophilic aerobic granular biomass for enhanced settleability

Aerobic biological wastewater treatment at thermophilic (ca. 55 degrees C) temperatures notoriously produces biomass that flocculates poorly or not at all. Contrary to this, thermophilic aerobic biomass that settled well in sequencing batch reactors was cultured with sludge volume index (SVI) values as low as 60mL/g. A mixture of granular and flocculant biomass resulted when closed reactors were sparged with recirculated reactor headspace gas containing some air, whereas a conventionally aerated control reactor sparged with air alone contained dispersed growth that did not flocculate. Maximum granule diameter was from 1.2 to 1.9mm, and granule resistance to disintegration was comparable to aerobic mesophilic granules. Two bacteria were isolated and identified as Anoxybacillus flavothermus and Pseudoxanthomonas taiwanensis as determined by partial 16S rDNA sequencing. Anoxybacilli species are alkaliphilic or alkalitolerant, with the type species having an obligate requirement for carbonate, even when grown on glucose. We postulate that high alkalinity and CO(2) may select for a population of aerobic thermophilies that flocculates and granulates.

Schlegelella aquatica sp. nov., a novel thermophilic bacterium isolated from a hot spring

A moderately thermophilic bacterial strain designated wcf1T, isolated from a hot spring located in the Tainan area, southern Taiwan, was characterized using a polyphasic approach. The cells were Gram-negative, non-pigmented, rod-shaped, non-spore-forming and motile. Phylogenetic analysis using 16S rRNA gene sequences showed that the strain formed a monophyletic branch towards the periphery of the evolutionary radiation occupied by the genus Schlegelella; its only close neighbour was the type strain of Schlegelella thermodepolymerans, K14T (97.8 %). The isolate was clearly distinguishable from other strains using phylogenetic analysis, DNA–DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics. It was evident from the genotypic and phenotypic data that strain wcf1T represents a novel species in the genus Schlegelella, for which the name Schlegelella aquatica sp. nov. is proposed, with the type strain wcf1T (=BCRC 17557T=LMG 23380T).