• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.173-182
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• 1997

The bacterial strains, which utilizes 2,4,4'-trichloro-2'-hydroxydiphenyl ether(TCHDPE) as a sole carbon source, were isolated by selective enrichment culture from soil samples of industrial waste deposits. The bacterium that showed the highestt biodegradation activity was designated as EL-O47R The isolated strain EL-O47R was Identified as the genus Pseudomonas from the results of morphological, cultural, and biochemical tests. The optimum conditions of medium for the growth and the degradation of TCHDPE were TCHDPE 500 ppm, (NH4)2SO4 0.1% as the nitrogen source, initial pH 7.0±0.1, and 37℃, respectively. In this conditions, the regradation rate of TCHDPE was about 97%. Pseudomonas sp. EL-O47R was tested for resistance to several metal compounds and antibiotics. Pseudomonas sp. EL-O47R was moderately grown to Cd(NO3)2, ZnCl2, AgSO4, CuSO4 and HgCl2. This strain was sensitive to rifampicin and kanamycln but resistant to ampicillin, penicillin, tetracyclin and chloramphenlcol. Pseudomonas sp. EL-O47R was grown structurally related com- pounds and potential metabolites of TCHDPE, and has the stability on TCHDPE biodegradation.

• Journal of Environmental Science International
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• v.6 no.2
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• pp.153-163
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• 1997

In order to fad the most fitted biodegradation model, biodegradation kinetics model to the initial phenol and p-cresot concentrations were investigated and had been fitted by the linear regression. Bacteria capable of degrading p-cresol were isolated from soil by enrichment culture technique. Among them, strain Ml capable of degradillg p.rcresol has also degraded phenal and was identified as the genus Micrococcus from the results from of taxonomical studies. The optimal tonditlons for the biodegradation of phenal and p-cresol by Micrococcus sp. Ml were $NH_4NO_3$ 0.05%, pH 7.0, 3$0^{\circ}C$, respectively, and medium volume 100m1/250m1 shaking flask. iwicrococcus sp. Ml was able to grow on phenal concentration up to 14mM and p-cresol concelltration up to 0.8mM. With increasing substrate concentraction, the lag period increased, but the maximum specific growth rates decreased. The yield coefficient decreased with increasing substrate concentation. The biodegradation kinetics of phenol and p-cresol were best described by Monod with growth model for every experimented concentration. In cultivation of mixed substrate, p-cresol was degraded first and phenol was second. This result implies that p-cresol and phenol was not degraded simultaneously.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.109-115
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• 1982

A Corynebacterium sp. capable of utilizing diaminododecane (DAD) were isolated from the soil by enrichment culture. Among 9 different kinds of substituted alkanes containing CN, NH$_2$, Cl, and SH groups (monoteminally or diterminally substituted) tested as carbon source, the isolate, designated as DAD 2-2. utilized DAD, putrescine dihydrochloride, dodecanethiol, dodecane and lautylamine. Thioanisole, decanedithiol, dicyanooctane, laurylcyanide, and dichlorodecane were not utilized. When emulgen 950 was added to the medium, the growth of DAD 2-2 was greatly accelerated. Isolated DAD 2-2 grown in the medium with DAD as carbon source formed ethyl $\alpha$-ketoglutarate. Metabolic product of DAD 2-2 grown in a medium without nitrogen source was different from that of grown in a medium with NH$_4$NO$_3$. When glucose, putrescine, n-dodecane and other alkane derivatives were tested in place of DAD, isolate DAD 2-2 yielded products different from those they formed with DAD suggesting specificity of DAD as a carbon source.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.319-324
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• 1991

Three strains able to efficiently produce ethanol from cellulosic hydrolysates were isolated from soil samples by enrichment culture in liquid saccharified wheat bran medium. The profiles of physiological and biochemical properties of two yeasts KM-09 and KM-402 and a bacterium Hg-225 were almost identical from those of Candida sp. and Klebsiella sp., respectively. Strains KM-09 and HG-225 used xylose and cellobiose as fermentable sugars, and HG-225 had a wide range of sugar utilization for ethanol fermentation. The optimal pH and temperature for growth of KM-09, KM-402 and HG-225 were 5.8, 5.6 and 6.8 and 32t, $30^{\circ}C$~ and $38^{\circ}C$, respectively. During the ethanol fermentation in saccharified wheat bran by the isolated strains, optimal temperature for ethanol production was more or less higher than those for growth, and addition of 0.2% (w/v) $MgSO_4$, into the medium enhanced ethanol productivity. Of the three strains ethanol content of KM-09 was the highest with about 2.3% (v/v), and ethanol production rate of HG-225 was faster than the others and maximum productivity was after 4 days. KM-09 (1.42% v/v) and HG-225 (1.05%, vlv) produced ethanol from 4% (wIv) xylose but growth rate was slower than on glucose. Otherwise KM-402 showed the highest ethanol productivity on glucose, but no ethanol was detected on xylose and cellobiose.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.579-582
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• 2000

(R,S)-3-amino-n-butanoic acid$(DL-\;{\beta}\;-homoalanine)$ has been kinetically resolved using Alcaligenes denitrificans Y2k-2 as a biocatalyst, which was isolated from soil by enrichment culture, which was carried out with minimal media containing (R,S)-3-amino-n-butanoic acid as a sole nitrogen source. The enzyme which peformed this kinetic resolution assumed to belong to the ${\omega}-transaminase$ family, because A. denitrificans used pyruvate as amino acceptor and its transaminase activity was inhibited by gabaculine, aminooxy acetic acid and hydroxylamine. In whole cell reaction, (R,S)-3-amino-n-butanoic acid was kinetically resolved to the corresponding (R)-3-amino-n-butanoic acid with excellent E (>100) in the presence of pyruvate as an amino acceptor at $37^{\circ}C$. (S-specific) We observed the substrate inhibition for pyruvate at 100mM. In this study, characteristics of transaminase activity of Alcaligenes denitrificans Y2k-2, such as substrate specificity and thermostability, are carried out for the development of (R)-3- amino-n-butanoic acid production system.

• Korean Journal of Microbiology
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• v.16 no.4
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• pp.170-179
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• 1978

By the successive enrichment culture, more than 250 methanol-utilizing bacteria were isolated from various samples such as soil, waste water and sewage. Two strains of which were selected and tentatively identified as Acinetobacter sp. and Pseudomonas sp. experiments were carried out to determine the growth conditions for the higher biomass yield and to demonstrate the difference to protein composition dependent upon carbon sources of these two species. the results were as follows ; 1. the optimum pH was determined as 8 in the both species. The optimum temperature in Acinetobacter sp. was $25^{\circ}C{\sim}30^{\circ}C$ and pseudomonas sp. was $30^{\circ}C-35^{\circ}C$. The optimum initial concentration of mthanol was determined as 1-2% in Acinetobacter sp. and 2-3% in pseudomonas sp. 2. The optimum concnetrations of nitrogen source, micro-elements, and vitamins such as biotin and thiamine-HCl in Acnetobactar sp. were 1g $(NH_4)_3SO4,\;1{\sim}3mg\;Mn^{++},\;4mg\;Fe^{++},\;10{\mu}g\;biotin,\;and\;100{\mu}g$ thiamine-HCl per liter medium. In the Pseudomonas sp., 2g $(NH_4)_3SO4,\;1mg\;Mn^{++},\;trace\;amounts\;of\;Fe^{++},\;5{\mu}g\;biotin,\;and\;100{\mu}g$ thiamine HCl per liter were effective. Maximum biomass yield was 2.5g/l in Acinetobacter sp. and 4.8g/l in Pseudomonas sp. 3. Protein composition of the two strains exhibited that alkai-labile protein was higher than alkali-stable protein. In Pseudomonas sp., the contents of acid soluble fraction and alkali-stable protein of the cells grown in the methanol medium were higher than in sucrose medium. On the other hand, in Acinetobacter sp., alkalilabile protein of the cells grown in sucrose medium was higher than in methanol medium.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.286-290
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• 2010

C-1 compounds are observed in anaerobic sediment of high salt environments. Thus, surface sediments and waters from these environments are therefore potential habitats for aerobic methylotrophic microorganisms. The soil samples collected from saltern and tidal flat as inoculums and methanol as carbon and energy source was supplied. After subculture depending on the salt concentration, methanol oxidizing bacteria growth condition investigated, the results of methanol oxidizing bacteria can grow in salt conditions, and the maximum concentration was 20%. Analysis based on denaturing gradient gel electrophoresis of 16S rRNA genes indicates that Methelyophaga-like bacteria were dominants of methylotrophs in the enrichment culture. Quantitative PCR showed that archaeal cells were about 1-10% of bacterial cells. Additionally archaea were assumed not to be involved in methanol oxidation since bacterial antibiotics completely blocked the methanol oxidation. Our results suggest that Methelyophaga-like bacteria could be involved in C-1 compounds oxidation in hypersaline environments although those activities are sensitive to salinity above 20%.

• Korean Journal of Microbiology
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• v.27 no.1
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• pp.63-69
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• 1989

A pink-pigmented facultative methylotrophic bacterium, Methylobacterium sp. strain SY1, was isolated from soil through methanol-enrichment culture technique. The isolate was gram-negative, slightly curved rod, and motile by a single polarly inserted flagellum. The colony was smooth, bright pink, and slimy. The guanine plus cytosine content of the KNA was 66%. The cell was obigately aerobic and exhibited both catalase and oxidase activities. Carotenoid pigment and poly-$\beta$-hydroxybutyrate were present. It was found to have three kinds of plasmid with molecular weights 45,000, 38,500 and 23,000. Growth with methanol(0.5%) was fast ($t_{d}$=6.5h) and was optimal at $30^{\circ}C$ and at pH 7.0. The isolate could grow on several sugars, organic acids, amino acids, amines, and alcohols in addition to the methanol. Methanol was found to be assimilated through the serine pathway.

• Korean Journal of Microbiology
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• v.21 no.4
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• pp.191-196
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• 1983

A Corynebacterium sp. capable of utilizing diaminododecane (DAD) were isolated from the soil by enrichment culture. Among 9 different kinds of substituted alkanes containing CN, $NH_2$, Cl, and SH groups (monoterminally or diterminally substituted) tested as carbon source, the isolate, designated as DAD 2-3, utilized DAD, putrescine dihydrochloride, dodecane and laurylamine. Dodecanethiol, thioanisole, decanedithiol, dicyanooctane, laurylcyanide,and dichlorodecane were not utilized. When emulgen 950 was added to the medium, the growth of DAD 2-3 was slightly accelerated. Isolate DAD 2-3 grown in the medium with DAD as carbon source formed .alpha.-ketoglutaric acid. Metabolic product of DAD 2-3 grown in a medium without nitrogen source was different from that of grown in a medium with $NH_4NO_3$. When glucose, putrescine, n-dodecane and other alkane derivatives were tested in place of DAD, isolate DAD 2-3 yielded products different from those they formed with DAD suggesting specificity of DAD as a carbon source.