• Korean Journal of Microbiology
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• v.42 no.4
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• pp.313-318
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• 2006

A thermophilic bacterium producing the extracellular cellulase was isolated from soybean paste, and the isolate WL-12 has been identified as Bacillus licheniformis on the basis on its 16S rRNA sequence, morphology and biochemical properties. A gene encoding the cellulase of B. licheniformis WL-12 was cloned and its nucleotide sequence was determined. This cellulase gene, designated celA, consisted of 1,551 nucleotides, encoding a polypeptide of 517 amino acid residues. The gene product contained catalytic domain and cellulose binding domain. The deduced amino acid sequence was highly homologous to those of cellulases of B. licheniformis, B. subtilis and B. amytoliquefaciens belonging to the glycosyl hydrolase family 5. When the celA gene was highly expressed using a strong B. subtilis promoter, the extracellular cellulase was produced up to 7.0 units/ml in B. subtilis WB700.

• Journal of Microbiology
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• v.43 no.6
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• pp.561-568
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• 2005

A newly-isolated thermophilic strain of the zygomycete fungus Rhizomucor pusillus 13.36 produced highly active dextrinogenic and saccharogenic enzymes. Cassava pulp was a good alternative substrate for amylase production. Dextrinogenic and saccharogenic amylases exhibited optimum activities at a pH of 4.0-4.5 and 5.0 respectively and at a temperature of $75^{\circ}C$. The enzymes were highly thermostable, with no detectable loss of saccharogenic or dextrinogenic activity after 1 hand 6 h at $60^{\circ}C$, respectively. The saccharogenic activity was inhibited by $Ca^{2+}$ while the dextrinogenic was indifferent to this ion. Both activities were inhibited by $Fe^{2+}\;and\;Cu^{2+}$ Hydrolysis of soluble starch by the crude enzyme yielded $66\%$ glucose, $19.5\%$ maltose, $7.7\%$ maltotriose and $6.6\%$ oligosaccharides.

• Journal of Microbiology and Biotechnology
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• v.6 no.1
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• pp.30-35
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• 1996

Distillery wastewater was used in a thermophilic laboratory-scale two stage anaerobic digester to test the effects of the redox potential of the first acidogenic reactor on the performance of the system. The digester consisted of first a acidogenic reactor and the an upflow anaerobic sludge blanket (UASB) reactor. The digestor was operated at a hydraulic retention time (HRT) of 48 h. Under these conditions, about 90% of the chemical oxygen demand as measured by the chromate method ($COD_{cr}$) was removed with a gas production yield of 0.4 l/g-COD removed. The redox potential of the acidogenic reactor was increased when the reactor was purged with nitrogen gas or agitation speed was increased. The increase in reduction potential was accompanied by an increase in acetate production and a decrease in butyrate formation. A similar trend was observed when a small amount of air was introduced into the acidogenic reactor. It is believed that the hydrogen partial pressure in the acidogenic reactor was decreased by the above mentioned treatments. The possible failure of anaerobic digestion processes due to over-loading could be avoided by the above mentioned treatments.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.592-599
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• 2012

Bacillus licheniformis ${\alpha}$-amylase (BLA), a thermophilic counterpart of Bacillus amyloliquefaciens ${\alpha}$-amylase (BAA), is an appropriate model for the design of stabilizing mutations in BAA. BLA has 10 more histidines than BAA. Considering this prominent difference, in the present study, three out of these positions (I34, Q67, and P407; located in the thermostability determinant 1 region and Ca-III binding site of BAA) were replaced with histidine in BAA, using the site-directed mutagenesis technique. The results showed that the thermostability of P407H and Q67H mutants had increased, but no significant changes were observed in their kinetic parameters compared to that of the wild type. I34H replacement resulted in complete loss of enzyme activity. Moreover, fluorescence and circular dichroism data indicated a more rigid structure for the P407H variant compared with that of the wild-type BAA. However, the flexibility of Q67H and I34H mutants increased in comparison with that of wild-type enzyme.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1778-1784
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• 2002

Novel membrane lipids containing the unusual very long chain fatty $acid{\alpha}{\omega}-1316-dimethyloctacosanedioate$, dimethyl. Ester (DME C30) was isolated and purified from thermophilic anaerobic eubacterium, Thermoanaerobacter ethanolicus. Structures of the lipids containing the bifunctional fatty acyl components were proposed by various analyses such as $^1H,\;^{13}C,\;^{31}P$ nuclear magnetic resonance (NMR), Fourier transform infrared(FTIR) spectroscopy, gas chromatography/mass spectrometry (GC/MS) and fast atom bombardment mass spectrometry (FAB/MS). Combined with the GC/MS, $^1H,\;and\;^{13}C$NMR data, we confirmed that the head groups of the lipids contained the glycerol and/or glucosamine molecules. $^{31}P$ NMR spectrum also showed that the lipids contained phosphate in a phosphodiester linkage. The proposed structures of these novel lipid components were the ones in which two head groups were linked by the membrane spanning fatty acyl component(DME C30)and regular chain fatty acids on glycerol moiety of each head group.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3521-3524
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• 2010

MTH1880 is a hypothetical protein derived from Methanobacterium thermoautotrophicum, thermophilic methanogen. The solution structure determined by NMR spectroscopy showed that it has a novel $\alpha+\beta$-fold with a highly acidic ligand binding pocket. Since MTH1880 maintains its ultra-stable structural characteristics at both high temperature and pressure, it has been considered as an excellent model for studying protein folding. To initiate the structural and folding study of MTH1880 in proving its unusual stability, we performed the site directed mutagenesis and biochemical analysis of MTH1880 mutants. Data from circular dichroism and NMR spectroscopy suggest that the point mutations perturbed the structural stability of protein even though the secondary structure is retained. This study will provide the useful information in understanding the role of participating residues during folding-unfolding process and our result will be used in designing further folding experiments for hyper-thermopile proteins like MTH1880.

• Korean Journal of Agricultural Science
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• v.7 no.1
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• pp.44-51
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• 1980

The population of indole-forming thermophile was obtained for the first time several samples of soil and compost manure. The population was highly enriched by successive transfer in the tryptophan liquid medium treated with antibiotics and dilution subculture cloning. Both indole-forming thermophile might be a Gram-negative bacterium hitherto unknown, but its pure culture has not yet been established due to the inability to grow on the solid media.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.697-702
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• 2011

A strain of the cyanobacterium Arthrospira was isolated from Lake Chahannaoer in northern China and was characterized according to microscopic morphology, photosynthetic oxygen-evolving activity, growth rate, and nutritional profile. Compared with thermophilic Arthrospira species occurring naturally in tropical and subtropical lakes, this isolate is mesophilic and grows optimally at ${\sim}20^{\circ}C$. The total protein, fatty acid, phycocyanin, carotenoid, and chlorophyll a contents were 67.6, 6.1, 4.32, 0.29, and 0.76 grams per 100 grams of dry weight, respectively. The strain is rich in polyunsaturated fatty acids (PUFAs). An essential omega-3 fatty acid, docosahexaenoic acid (DHA), was detected, and ${\gamma}$-linolenic acid (GLA) and DHA accounted for 28.3% of the total fatty acid content. These features of this newly isolated strain make it potentially useful in commercial mass culture in local areas or as a biofuel feedstock. It is also an alternative resource for studying the metabolic PUFA pathways and mechanisms of cold stress tolerance in cyanobacteria.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.106-117
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• 2013

Microbial enhanced oil recovery (MEOR) is one of the most economical and efficient methods for extending the life of production wells in a declining reservoir. Microbial consortia from Wafra oil wells and Suwaihat production water, Al-Wusta region, Oman were screened. Microbial consortia in brine samples were identified using denaturing gradient gel electrophoresis and 16S rRNA gene sequences. The detected microbial consortia of Wafra oil wells were completely different from microbial consortia of Suwaihat formation water. A total of 33 genera and 58 species were identified in Wafra oil wells and Suwaihat production water. All of the identified microbial genera were first reported in Oman, with Caminicella sporogenes for the first time reported from oil fields. Most of the identified microorganisms were found to be anaerobic, thermophilic, and halophilic, and produced biogases, biosolvants, and biosurfactants as by-products, which may be good candidates for MEOR.

• Environmental Engineering Research
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• v.23 no.3
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• pp.258-264
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• 2018

The objectives of this research were to 1) isolate and identify thermophilic bacteria for food waste treatment; 2) investigate the capability of food waste treatment using Bacillus species; and 3) develop air-dried Bacillus starters for food waste treatment. Five Bacillus species were isolated from food wastes and identified as Bacillus licheniformis (B. licheniformis) G1, Bacillus circulans C2, Bacillus subtilis (B. subtilis) E1, Bacillus vanillea F1, and Bacillus atrophaeus G2 based on 16S rDNA sequencing. Each identified Bacillus and the mixture of Bacillus species were cultivated in the standard food waste at $45^{\circ}C$ for 8 d. Changes in cell count, solid contents, and pH of the food waste were monitored during cultivation. Air-dried Bacillus cell powders were prepared using wheat flour and lactomil as excipients, and the cell count and survival rate were determined. The cell count of B. licheniformis G1 exhibited the highest number among the tested Bacillus (${\sim}10^8CFU/mL$). The greatest reduction in solid contents of food waste was achieved by B. subtilis E1 (22.6%). The mixture of B. licheniformis G1 and B. subtilis E1 exhibited a synergistic effect on the reduction of solid contents. Lactomil was determined as better excipient than wheat flour based on the greatest survival rate of 95%.