Characterization of Symbiobacterium toebii , an obligate commensal thermophile isolated from compost

Abstract

A symbiotic thermophilic bacterium, strain SC-1, was isolated from hay compost (toebi) in Korea. The new isolate exhibited an obligate commensal interaction with a thermophilic Geobacillus strain and required crude extracts and/or culture supernatant from Geobacillus sp. SK-1 for axenic growth. The growth factors from Geobacillus sp. SK-1 were irreversibly inactivated by phenol or protease treatment, suggesting that they might be proteins. The cells of strain SC-1 were non-spore forming, nonmotile rods that were stained Gram-negatively. The isolate was a microaerophilic heterotroph. Growth was observed between 45 degrees and 70 degrees C (optimum: 60 degrees C; 2.4-h doubling time) and pH 6.0 and 9.0 (optimum: pH 7.5). The G+C content of the genomic DNA was 65 mol%, and the major quinones were MK-6 and MK-7. A phylogenetic analysis of its 16S rDNA sequence indicated that strain SC-1 is closely related to Symbiobacterium thermophilum and so was named Symbiobacterium toebii on the basis of its physiological and molecular properties.

Phylogenetic diversity of Fe(III)-reducing microorganisms in rice paddy soil: enrichment cultures with different short-chain fatty acids as electron donors

“…The potential for Symbiobacterium to be involved in nitrate respiration has been proven (Rhee et al 2002;Ueda et al 2004), however, Symbiobacterium species have so far not been directly linked to Fe(III)-reducing activity. The distinct community structure between the control and the treatments indicated that other organic carbons rather than those chosen as electron donors/substrates in the present study was used by the Fe(III) reducers in control, which suggests that the potential electron donors/substrates for Fe(III) reducers is more complicated in paddy soils in situ.…”

Reference gene validation for qPCR in rat carotid body during postnatal development

“…Using the direct cultivating method with CFE of partner bacterium, we successfully isolated an intriguing bacterium from compost in the natural environment. The taxonomic analysis using 16S rDNA sequence revealed that it belonged to Symbiobacterium , in which growth absolutely depends on co-existence of the helper bacterium, Geobacillus species [14,15]. Studies of the distribution and diversity of Symbiobacterium species using competitive quantitative PCR, terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis revealed that these bacteria are widespread in natural environments, including compost, animal faeces, feeds and soils [16-19].…”

Synergism of Glycoside Hydrolase Secretomes from Two Thermophilic Bacteria Cocultivated on Lignocellulose

“…In order to purify those bacteria, they must be grown in the presence of specific compounds designated growth-supporting factors (GSF), supplied in nature by a neighboring or partner bacterium. Many methods involving GSF have been developed, such as the use of a diffusion chamber (26), the addition of culture supernatants (29,30) or cell extracts (CFE) of other microorganisms (27,(31)(32)(33), or cocultivation with a defined helper bacterium (28). The growth of commensal thermophiles, which are widely distributed in environmental samples, was greatly enhanced by the addition of Geobacillus toebii CFE to the culture medium (34).…”