Dataset Information

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).

SUBMITTER: Shang SM

PROVIDER: S-EPMC3668118 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Four closely related facultative anaerobe, moderately thermophilic, Gram positive rods (JS1(T), JS5, JS11, and JS15) were isolated from sediment samples from a hot spring at Suryakund, Jharkhand, India. Colonies were pale yellow, rough surface with uneven edges on TSA after 72 h incubation. Heterotrophic growth was observed at 40-60°C and pH 5.5-11.5; optimum growth occurred at 55°C and pH 7.5. 16S rRNA gene sequence analysis revealed the strains belong to genus Anoxybacillus. DNA-DNA homology values among strains were above 70% and showed distinct ERIC and REP PCR profile. On the basis of morphology and biochemical characteristics, strain JS1(T) was studied further. Strain JS1(T) showed 99.30% sequence similarity with A. flavithermus subsp. yunnanensis, 99.23% with A. mongoliensis, 99.16% with A. eryuanensis, 98.74% with A. flavithermus subsp. flavithermus, 98.54% with A. tengchongensis, 98.51% with A. pushchinoensis, 97.91% with A. thermarum, 97.82% with A. kaynarcensis, 97.77% with A. ayderensis and A. kamchatkensis, 97.63% with A. salavatliensis, 97.55% with A. kestanbolensis, 97.48% with A. contaminans, 97.27% with A. gonensis and 97.17% with A. voinovskiensis. In 16S rRNA secondary structure based phylogenetic comparison, strain JS1(T) was clustered with Anoxybacillus eryuanensis, A. mongoliensis, and A. flavithermus subsp. yunnanensis and showed 15 species specific base substitutions with maximum variability in helix 6. Moreover, DNA-DNA relatedness between JS1(T) and the closely related type strains were well below 70%. The DNA G+C content was 42.1 mol%. The major fatty acids were C(15:0 iso), C(16:0 iso) and C(17:0iso). The polar lipids were a phosphatidylgylycerol, a diphosphatidylglycerol, a phosphatidylethnolamine, a phosphatidylcholine, a phosphatidyl monomethylethanolamine and four unknown lipids. Based on polyphasic approach, strain JS1(T) represent a novel species of the genus Anoxybacillus for which Anoxybacillus suryakundensis sp. nov. is proposed. The type strain is JS1(T) (= DSM 27374(T) = LMG 27616(T) =JCM19211(T)).

Project description:BackgroundCellulose-degrading thermophilic anaerobic bacterium as a suitable host for consolidated bioprocessing (CBP) has been proposed as an economically suited platform for the production of second-generation biofuels. To recognize the overall objective of CBP, fermentation using co-culture of different cellulolytic and sugar-fermenting thermophilic anaerobic bacteria has been widely studied as an approach to achieving improved ethanol production. We assessed monoculture and co-culture fermentation of novel thermophilic anaerobic bacterium for ethanol production from real substrates under controlled conditions.ResultsIn this study, Clostridium sp. DBT-IOC-C19, a cellulose-degrading thermophilic anaerobic bacterium, was isolated from the cellulolytic enrichment cultures obtained from a Himalayan hot spring. Strain DBT-IOC-C19 exhibited a broad substrate spectrum and presented single-step conversion of various cellulosic and hemicellulosic substrates to ethanol, acetate, and lactate with ethanol being the major fermentation product. Additionally, the effect of varying cellulose concentrations on the fermentation performance of the strain was studied, indicating a maximum cellulose utilization ability of 10 g L-1 cellulose. Avicel degradation kinetics of the strain DBT-IOC-C19 displayed 94.6% degradation at 5 g L-1 and 82.74% degradation at 10 g L-1 avicel concentration within 96 h of fermentation. In a comparative study with Clostridium thermocellum DSM 1313, the ethanol and total product concentrations were higher by the newly isolated strain on pretreated rice straw at an equivalent substrate loading. Three different co-culture combinations were used on various substrates that presented two-fold yield improvement than the monoculture during batch fermentation.ConclusionsThis study demonstrated the direct fermentation ability of the novel thermophilic anaerobic bacteria on various cellulosic and hemicellulosic substrates into ethanol without the aid of any exogenous enzymes, representing CBP-based fermentation approach. Here, the broad substrate utilization spectrum of isolated cellulolytic thermophilic anaerobic bacterium was shown to be of potential utility. We demonstrated that the co-culture strategy involving novel strains is efficient in improving ethanol production from real substrate.

Dataset Information

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets