Themoanaerobacterium calidifontis sp. nov., a novel anaerobic, thermophilic, ethanol-producing bacterium from hot springs in China

Abstract

A novel thermophilic Gram staining positive strain Rx1 was isolated from hot springs in Baoshan of Yunnan Province, China. The strain was characterized as a hemicellulose-decomposing obligate anaerobe bacterium that is rod-shaped (diameter: 0.5–0.7 μm; length: 2.0–6.7 μm), spore-forming, and motile. Its growth temperature range is 38–68 °C (optimum 50–55 °C) and pH range is 4.5–8.0 (optimum 7.0). The maximum tolerance concentration of NaCl was 3 %. Rx1 converted thiosulfate to elemental sulfur and reduced sulfite to hydrogen sulfide. The bacterium grew by utilizing xylan and starch, as well as a wide range of monosaccharide and polysaccharides, including glucose and xylose. The main products of fermentation were ethanol, lactate, acetate, CO2, and H2. The maximum xylanase activity in the culture supernatant after 30 h of incubation at 55 °C was 16.2 U/ml. Rx1 DNA G + C content was 36 mol %. 16S rRNA gene sequence analysis indicated that strain Rx1 belonged to the genus Thermoanaerobacterium of the family ‘Thermoanaerobacteriaceae’ (Firmicutes), with Thermoanaerobacterium aciditolerans 761–119 (99.2 % 16S rRNA gene sequence similarity) being its closest relative. DNA–DNA hybridization between Rx1 and T. aciditolerans 761–119 showed 36 % relatedness. Based on its physiological and biochemical tests and DNA–DNA hybridization analyses, the isolate is considered to represent a novel species in the genus Thermoanaerobacterium, for which the name Thermoanaerobacterium calidifontis sp. nov. is proposed, with the type strain is Rx1 (=JCM 18270 = CCTCC M 2011109).Electronic supplementary materialThe online version of this article (doi:10.1007/s00203-013-0895-5) contains supplementary material, which is available to authorized users.

Production, Purification, and Characterization of Thermostable Alkaline Xylanase From Anoxybacillus kamchatkensis NASTPD13

“…Bacterial growth was monitored by measuring absorbance at 600 nm (turbidity measurements). The aliquots after absorbance measurements were centrifuged (12,000 × g, 10 min) to remove all solids including the bacterial cells and supernatants were analyzed for xylanase activity as described above (Shang et al, 2013 ).…”

Bacterial xylanases: biology to biotechnology

“…strain XI 36.3 IU/ml Wheat bran 60 °C; pH 9.0 Raj et al ( 2013 ) 15 Stenotrophomonas maltophilia 26.4 IU/ml Wheat bran 80 °C; pH 9.0 Raj et al ( 2013 ) 16 Thermoanaerobacterium calidifontis sp.nov. 16.2 U/ml Oat spelt xylan 50–55 °C; pH 7.0 Shang et al ( 2013 ) …”

Xylanase and Its Industrial Applications

“…The isolation of thermophilic gram positive strain Rxl, a member of genus Thermoanaerobacterium with xylan degrading ability was reported from hot springs in Baoshan of Yunnan Province, China. The successful cultivation of the bacterium was made through utilization of xylan, starch and wide range of monosaccharide and polysaccharides [27]. Others like xylanase genes, was cloned from bacterial strain Planococcus sp., SL4, was isolated from the sediment of Soda Lake Dabusu of high alkalinity nature [28].…”