• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.822-828
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• 2004

Nopaline-type Agrobacterium tumefaciens strain C58 cannot utilize octopine (Oct) as the sole carbon and nitrogen sources. This strain harbors two plasmids; a virulent plasmid, pTiC58, and a megaplasmid, pAtC58. From strain NT1, which is a derivative of C58 harboring only pAtC58, we isolated spontaneous mutants that utilize Oct as the sole nitrogen source. These Oct-catabolizing mutants, however, could not utilize the opine as the sole carbon source. In contrast, strain UIA5, a plasmid-free derivative of C58, could not give rise to such mutants. The mutations isolated from NT1 were mapped to socR in pAtC58, which is a negative regulator of the soc operon responsible for the uptake and catabolism of an Amadori opine, deoxyfructosyl glutamine (Dfg). A derivative of UIA5 carrying a clone of the soc operon with a transposon inserted in socR also utilizes Oct as the sole nitrogen source. However, UIA5 harboring the operon with mutations in each of the structural genes in the soc operon, socA, B, C, and D, lost the ability to generate spontaneous Oct-utilizing mutants, suggesting that soc genes in pAtC58 are required for the utilization of Oct as a nitrogen source, and that derepressed expression of these genes allows cells to utilize Oct. In contrast, Oct-catabolizing mutants derived from C58, which grew using Oct as the sole nitrogen source, could also utilize the opine as the sole carbon source. These mutants did not carry any detectable mutations in socR or the region upstream to the gene in pAtC58, suggesting that mutations occurring elsewhere in the genome, most likely in pTiC58, allow the uptake and catabolism of the opine.

• 상하수도학회지
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• 제20권6호
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• pp.829-836
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• 2006

The reaction rate of denitrification is primarily affected by the utilization of organics that are usually limited in the anoxic period in a sequencing batch reactor. It is necessary to add an extemal carbon source for sufficient denitrification. An adaptive model of state-space based on the extended Kalman filter is applied to manipulate the dosage rate of extemal carbon automatically. Control strategies for denitrification have been studied to improve control performance through simulations. The normal control strategy of the constant set-point results in the overdosage of external carbon and deterioration of water quality. To prevent the overdosage of external carbon, improved control strategies such as the constrained control action, variable set-point, and variable set-point after dissolved oxygen depletion are required. More stable control is obtained through the application of the variable set-point after dissolved oxygen depletion. The converging value of the estimated denitrification coefficient reflects conditions in the reactor.

• Environmental Engineering Research
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• 제21권3호
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• pp.297-303
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• 2016

Global warming due to greenhouse gases is an issue of great concern today. Fossil fuel power plants, especially coal-fired thermal power plants, are a major source of carbon dioxide emission. In this work, carbon capture and utilization using sodium hydroxide was studied experimentally. Application for flue gas of a coal-fired power plant is considered. Carbon dioxide, reacting with an aqueous solution of sodium hydroxide, could be converted to sodium bicarbonate ($NaHCO_3$). A bench-scale unit of a reactor system was designed for this experiment. The capture scale of the reactor system was 2 kg of carbon dioxide per day. The detailed operational condition could be determined. The purity of produced sodium bicarbonate was above 97% and the absorption rate of $CO_2$ was above 95% through the experiment using this reactor system. The results obtained in this experiment contain useful information for the construction and operation of a commercial-scale plant. Through this experiment, the possibility of carbon capture for coal power plants using sodium hydroxide could be confirmed.

• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.91-104
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• 2019

The taxonomic and functional characteristics of bacterial communities in the pre-chlorinated rapid filters and ozonated biological activated carbon (BAC) filters were compared using Illumina MiSeq sequencing of the 16S rRNA gene and community-level physiological profiling (CLPP) based on sole-carbon-source utilization patterns. Both the rapid filters and BAC filters were dominated by Rhizobiales within ${\alpha}-proteobacteria$, but other abundant orders and genera were significantly different in both types of filter. Firmicutes were abundant only in the intermediate chlorinated rapid filter, while Acidobacteria were abundant only in the BAC filters. Bacterial communities in the rapid filter showed high utilization of carbohydrates, while those in the BAC filters showed high utilization of polymers and carboxylic acids. These different characteristics of the bacterial communities could be related to the different substrates in the influents, filling materials, and residual disinfectants. Chlorination and ozonation inactivated the existing bacteria in the influent and formed different bacterial communities, which could be resistant to the oxidants and effectively utilize different substrates produced by the oxidant, including Phreatobacter in the rapid filters and Hyphomicrobium in the BAC filters. Bradyrhizobium and Leptothrix, which could utilize compounds adsorbed on the GAC, were abundant in the BAC filters. Ozonation increased taxonomic diversity but decreased functional diversity of the bacterial communities in the BAC filters. This study provides some new insights into the effects of oxidation processes and filling materials on the bacterial community structure in the biological filters of drinking water treatment plants.

• Journal of Microbiology and Biotechnology
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• 제7권1호
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• pp.68-74
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• 1997

One hundred and eighty two lactic acid bacteria, isolated mainly from kimchi, including reference strains were examined for their ability to utilize 95 carbon sources. The test strains were assigned to 5 major, 1 minor and 12 single-membered clusters based on the $S_{SM}$, UPGMA algorithm (at similarity of $80{\%}$). These aggregate clusters were equivalent to the genus Leuconostoc (aggregate cluster M and N), the genus Lactobacillus (aggregate cluster Q and R), and the genera Lactobacillus and Leuconostoc (aggregate cluster O and P) according to the database of the Biolog system. This study demonstrates that rapid identification and classification of isolates originating from kimchi can be achieved on the basis of such carbon source utilization tests.

• 미생물학회지
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• 제38권2호
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• pp.57-61
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• 2002

전라남도 장흥군 인근 해안에서 채집한 불가사리(Asterias amurensis)를 대상으로 불가사리의 장내에 분포하는 종속영양세균의 균체수를 측정하였고, 분리동정된 균주들을 대상으로 탄소원 이용 특성을 조사하였다. 불가사리의 장내에 분포하는 종속영양세균의 균체수는8.65$\pm$0.65 $\times$$10^3$ cfu . g$^{-1}$이 였으며, 분리 동정된 24균주(그람음성균 11균주, 그람양성균이 13균주)중에서 Vibrio속,Staphylococcus속, Corynebacterium속이 높게 나타났다. 불가사리 장내에서 분리 동정된 세균들은 그람양성의 간균이 높은 비율을차지하였고, catalase와 oxidase의 활성은 각각 54.2%,20.8%로 나타났다. 그람음성균의 경우, 탄소원으로 glucose의 이용률이 가장 높았고, 그 다음으로 sucrose, mannose, maltose,그리고 trehalose의 순으로 높은 이용률을 나타냈으며, adipate, phenol acetate는 이용하지 못하였다. 그람양성균의 경우, glucose가 가장 높은 이용률을 나타냈고, 그 다음은 fructose, trehalose, maltose 순으로 높은 이용률을 보였다.

• Journal of Plant Biology
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• 제16권1_2호
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• pp.6-11
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• 1973

The utilization of acetate by Dunaliella tertiolecta was examined, and the detections and assays of the enzymes of the tricarboxylic acid cycle and the glyoxylate pathway were described. Acetate could not be utilized as a sole carbon source for the growth. The carboxyl carbon of acetate was incorporated more rapidly into CO2 than the methyl carbon. It was identified that malate, succinate, citrate and etc., were accumulated whne [U-14C] acetate was supplied to the cell free homogenate. The following enzyme activities were measured; acetothiokinase, isocitrate dehydrogenase, fumarase, malate dehydrogenase and aconitase. Though isocitratase, malate synthetase, succinate dehydrogenase and oxoglutarate dehydrogenase could not be detected, 14C from succinate was easily contributed to CO2 and cell component. The evidence suggested that the glyoxylate pathway was not operative and showed that the TCA cycle was the all important pathway in the oxidation of acetate to CO2 in Dunaliella.

• 한국미생물·생명공학회지
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• 제10권2호
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• pp.109-115
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• 1982

토양으로 부터 diaminododecane 자화균 DAD2-2주를 분리하여 검토한 결과 Corynebacterium속으로 동정되었으며 DAD2-2주의 alkane 유도체에 대한 생육특성조사에서 putrescine dihydrochloride, dodecanethiol, dodecane. laurylamine등은 탄소원으로 이용될 수 있었으나 thioanisole, decanedithiol, dicyanooctane, 1aurylcyanide, dichlorodecane등은 이용되지 못하였다. Emulgen 25ppm을 DAD배지에 첨가하였을 경우 DAD2-2주에 의한 diaminododecane 자화가 현저하게 촉진되었으며 diaminododecane자화시 생성되는 중간생성물은 ethyl $\alpha$-ketoglutarate로 동정되었다. 그러나 diaminododecane을 탄소원 뿐만 아니라 질소원으로도 이용하였을 경우에 있어서는 ethyl $\alpha$-ketoglutarate와는 다른 생성물을 생성하였으며 diaminododecane 대신 glucose, putrescinc, n-dodecane을 생육기질로 이용하였을 때에도 ethyl $\alpha$-ketoglutarate와는 다른 생성물을 생성하였다. 또한 resting cell을 이용하여 alkane 유도체를 co-oxidation시키는 과정에서도 ethyl $\alpha$-ketoglutarate와는 상이한 생성물이 생성되었다.

• 미생물학회지
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• 제21권4호
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• pp.191-196
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• 1983

토양으로부터 diaminododecane 자화균 DAD2-3주를 분리하여 Coryηebacterium속으로 동정하였다. DADZ2-3의 alkane유도체에 대한 생육특성조사에서 putrescine, dodecane, laurylamine 등은 탄소원으로 이용되었으나 dod-ecanethiol, thioanisole, decanedithiol, dicyanooctane, laurylcyanide, dichlorodecane등은 이용되지 못하였으며, emulgen 첨가에 의한 diaminododecane 자화촉진 효과는 미세하였다. DAD2-3림에 의해 diaminododecane 자화시 생성되는 중간생성불은 $\alpha$-ketoglutaric acid로 동정되었다. 그러나 d diaminododecane을 탄소원 뿐만 아니라 질소원으로도 이용하었을 경우 $\alpha$-ketoglutaric acid와는 상이한 중간 생성 풍을 생성하였으며, 탄소원으로 diaminododecane 대신 glucose, putrescine, n-dodecane을 사용하였을 경우와 또한 resting cell을 이용하여 여러가지 다른 alkane유도체를 co-oxidation시키는 과정에서도 $\alpha$-ketoglutaric acid와는 상이한 생성물이 생성되었다.

• Journal of Microbiology and Biotechnology
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• 제18권11호
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• pp.1773-1784
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• 2008

Effects of various industrially important carbon sources (glucose, sucrose, xylose, gluconate, and glycerol) on shikimic acid (SA) biosynthesis in Escherichia coli were investigated to gain new insight into the metabolic capability for overproducing SA. At the outset, constraints-based flux analysis using the genome-scale in silico model of E. coli was conducted to quantify the theoretical maximum SA yield. The corresponding flux distributions fueled by different carbon sources under investigation were compared with respect to theoretical yield and energy utilization, thereby identifying the indispensable pathways for achieving optimal SA production on each carbon source. Subsequently, a shikimate-kinase-deficient E. coli mutant was developed by blocking the aromatic amino acid pathway, and the production of SA on various carbon sources was experimentally examined during 51 batch culture. As a result, the highest production rate, 1.92 mmol SA/h, was obtained when glucose was utilized as a carbon source, whereas the efficient SA production from glycerol was obtained with the highest yield, 0.21 mol SA formed per mol carbon atom of carbon source consumed. The current strain can be further improved to satisfy the theoretically achievable SA production that was predicted by in silico analysis.