• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.903-908
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• 2001

The gene aeg-46.5, which is expressed under anaerobic condition, has putative triple -10 regions and four transcription start sites. The mRNA transcription level and its start point change depending on the aerobic/anaerobic growth condition. RNA polymerase and its regulatory proteins must choose which of three -10 region to use. The putative triple 10 region was mutated to make only one of them function with consensus -10 region sequence (TATAAT) and the other two as non-functional region. The results show that the second and third -10 regions are used for the aerobic/anaerobic expression. The third -10 region is responsible for the high aerobic to anaerobic switch ratio. This suggests that only the last two of the putative triple -10 region have functions on aeg-46.5 gene expression switch control. The phenotype of the mutated promoter was tested in the wild type cell and narL - cell. The results indicate that the control by NarL is independent from the selection of -10 region. The expression patterns on multi-copy plasmids and on single-copy chromosome were compared. These results show that the aerobic/anaerobic switch control of aeg-46.5 is through the choice of -10 region. The mechanism of choosing different -10 region remains to be seen.

• 상하수도학회지
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• 제29권2호
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• pp.203-209
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• 2015

The purpose of this study is to estimate the applicability of a stable anaerobic digester using a separator membrane to the preprocessing thickening process. The results of the experiments showed about a 47.16% weight loss rate for the sludge under anaerobic condition, and about 41.17% under intermittent aeration condition. The concentrations of rejection water were $SCOD_{Cr}$ 25 mg/L, T-N 16.6 mg/L, and T-P 1.4 mg/L on the average under the intermittent aeration condition, which were lower than the concentrations of rejection water under an anaerobic condition. As for the factors affecting the reduction of the flux, correlation analyses of TTF, MLSS, $SCOD_{Cr}$, and $EPS_{Protein}$, $EPS_{Polysacchride}$ resulted in -0.97, -0.95, -0.84 and -0.86, -0.95, respectively, which showed that TTF had the highest correlation to the reduction of the flux. In addition, it was concluded that MLSS, $SCOD_{Cr}$ and $EPS_{Protein}$, $EPS_{Polysacchride}$ also have close correlations. The results are considered to show that, in the case of the process using a tubular membrane in the preprocessing process of an anaerobic digester, an intermittent aeration condition of the thickener considering the contamination of the membrane and load of rejection water is appropriate for the stable preprocessing process.

• 한국환경농학회지
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• 제17권4호
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• pp.301-305
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• 1998

본 연구는 농가에서 사용하는 저류조, 연속 폭기조, 혐기성 정치식, 혐기성 교반식의 4가지 형태의 부숙조를 이용하여 액상 가축분 퇴비 부숙효율을 평가하기 위하여 수행하였다. 호기성 폭기조는 BOD 및 악취 제거율에서 혐기성 부숙방법보다 우수하였다. 반면에 질소는 초기농도의 47%가 손실되어 혐기성 부숙방법보다 심한 편이었다. 혐기성 부숙방법중 교반식과 정치식간에는 큰 차이는 인정되지 않았다. 그러나 혐기성 교반식이 정치식보다 대장균 제거율, 악취제거율은 더 높았으며, 질소 손실율은 더 낮게 나타났다. 농가에서 사용하는 저류조 형태의 부숙조는 혐기 또는 호기성 처리 방법보다 BOD, 대장균, 악취제거율등이 낮았다. 각 개별요인들의 효율을 종합 평가한 결과 액비 부숙효율은 혐기성 교반조>호기성 폭기조>무교반 혐기성조>저류조 순으로 높았다.

• Journal of Microbiology and Biotechnology
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• 제11권3호
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• pp.406-411
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• 2001

In a bacterial denitrification test with Pseudomonas sp. and anaerobic consortium, more nitrates and less substrate were consumed but less metabolic nitrite was produced under an anaerobic $H_2$ condition rather than under $N_2$ condition. In a bioelectrochemical denitrification test with the same organisms, the electrochemically reduced neutral red was confirmed to be a substitute electron donor and a reducing power like $H_2$. The biocatalytic activity of membrane-free bacterial extract, membrane fraction, and intact cell for bioelectrochemical denitrification was measured using cyclic voltammetry. When neutral red was used as an electron mediator, the electron transfer from electrode to electron acceptor (nitrate) via neutral red was not observed in the cyclic voltammogram with the membrane-free bacterial extract, but it was confirmed to gradually increase in proportion to the concentration of nitrate in that of the membrane fraction and the intact cell of Pseudomonas sp.

• Journal of Microbiology
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• 제33권3호
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• pp.234-238
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• 1995

The breakdown rate of NAD in Salmonella typhimurium was investigated both in aerobic and anaerobic conditions. After NAD is broken down to nicotinamide ring containing moiety, almost all the nicotinamide ring containing moiety recycles back to NAD pool. However almost none of the adenine containing moiety recycles back. We pulse-label the endogeneous NAD with [$\^$14/C]-adenine and [$\^$3/H]- niacin. The remaining [$\^$14/C]-radioactivity in NAD pool at each time was regarded as unbroken portion of NAD, WHERE AS THE OF [$\^$3/H] was served as a total amount of NAD to start with. Under aerobic condition, the half-life of NAD was around 2 hours. However, the breakdown rate was significantly reduced (around 3-5 fold) under anaerobic condition. The observation that under aerobic conditions, NAD turnover is considerably faster than under anaerobic conditions suggests that oxygen has important effect in NAD breakdown.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1958-1965
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• 2008

A denitrifying polyphosphate-accumulating bacterium (YKP-9) was isolated from activated sludge of a 5-stage biological nutrient removal process with step feed system. This organism was a Gram-negative, coccus-shaped, facultative aerobic chemoorganotroph. It had a respiratory type of metabolism with oxygen, nitrate, and nitrite as terminal electron acceptors. The 16S rRNA gene sequence of strain YKP-9 was most similar to the 16S rRNA gene sequence of Paracoccus sp. OL18 (AY312056) (similarity level, 97%). Denitrifying polyphosphate accumulation by strain YKP-9 was examined under anaerobic-anoxic and anaerobic-oxic batch conditions. It was able to use external carbon sources for polyhydroxyalkanoates(PHA) synthesis and to release phosphate under anaerobic condition. It accumulated polyphosphate and grew a little on energy provided by external carbon sources under anoxic condition, but did neither accumulate polyphosphate nor grow in the absence of external carbon sources under anoxic condition. Cells with intracellular PHA cannot accumulate polyphosphate in the absence of external carbon sources under anoxic condition. Under oxic condition, it grew but could not accumulate polyphosphate with external carbon sources. Based on the results from this study, strain YKP-9 is a new-type denitrifying polyphosphate-accumulating bacterium that accumulates polyphosphate only under anoxic condition, with nitrate and nitrite as the electron acceptors in the presence of external carbon sources.

• Environmental Engineering Research
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• 제10권5호
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• pp.257-263
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• 2005

A batch and a continuous type experiments were conducted to test the conditions for simultaneous phosphorus release and uptake, and denitrification, taking place in one process. The bacteria able to denitrify as well as to remove phosphorus were evaluated for the application to biological nutrient removal(BNR) process. In the batch-type experiment, simultaneous reactions of phosphorus release and uptake, and also denitrification were observed under anoxic condition with high organic and nitrate loading. However the rate and the degree of P release were lower than that occurred under anaerobic condition. BNR processes composed of anaerobic-anoxic-oxic(AXO), anoxic-anaerobic-oxic(XAO) and anoxic-oxic(XO) were operated in continuous condition. The anoxic reactors in each process received nitrate loading. In the AXO process, P release in anaerobic reactor and the luxury uptake in oxic reactor proceeded actively regardless to nitrate loading. However in XAO and XO processes, P release and luxury uptake occurred only with the nitrate loading less than $0.07\;kg{NO_3}^--N$/kgMLSS-d. With higher nitrate load, P release increased and the luxury uptake decreased. Therefore, it appeared that the application of denitrifying phosphorus-removing bacteria (DPB) to BNR process must first resolve the problem with decrease of luxury uptake of phosphorus in oxic reactor.

• 대한미생물학회지
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• 제20권1호
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• pp.35-44
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• 1985

Isolation and identification of anaerobic bacteria from blood cultures are still technically demanding procedures. Recently, with the use of gas liquid chromatography, the accuracy of identification is much improved. However, there has never been a satisfactory data analysis on anaerobic bacteremia in Korea. The authors evaluated both the clinical and the bacteriological data of 129 anaerobic bacteremias found at the Yonsei Medical Center during the period of 1973 to 1984. The most frequently isolated anaerobic bacteria were Bacteroides (52.7%), among which the major species was B. fragilis (38.7%). Incidence of anaerobic bacteremia by sex was 57% in male and 43% in female. Mortality was higg in groups below 1-year old and above 50-year old. The cause of death seemed closely correlated with the patient's age, general condition and the severity of the underlying disease. Various neoplasms were the most common (20%) underlying diseases predisposing the anaerobic bacteremia. Biliary tract was considered the most frequent route of infection in anaerobic bacteremia. The frequent clinical signs in anaerobic bacteremia were fever (65%), followed by liver function abnormality (29%), jaundice (20%) and hypotention(18%). When analysis of positive rate of blood culture was made on the patients from whom 4 cultures were done within 24 hours, it was found that 33% of the samples were positive. Isolation rate of anaerobic bacteria in thioglycollate medium was 83.8%, while it was 44% in Tryptic soy broth. Among the anaerobic bacteremia, 25.4% were polymicrobial infections with aerobic bacteria (92.5%), such as E. coli(33.3%). From these studies, it is concluded that B. fragilis is the most important causative organism in anaerobic bacteremia, with high fatality, particularly in those who have underlying diseases. The ports of entry are mainly biliary, gastrointestinal and female genital tract. Fever is the most frequent clinical sign. Single blood culture is not sufficient to detect all anaerobic bacteremia, therefore more cultures with optimal time interval are needed. The incidence of polymicrobial infection in anaerobic bacteremia is higher than that in overall bacteremia.

• 한국식품영양학회지
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• 제10권4호
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• pp.475-479
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• 1997

최소 배지에 여러 아미노산과 대사 산물을 첨가하여 혐기성 조건하에서 배양시킨 Serratia marcescens ATCC 25419 세포 추출무에서 prodigiosin의 생합성을 조사한 결과 아미노산과 대사 산물들은 prodigiosin 생합성을 대조군보다 50-80% 정도 감소시켰다. 글리옥실산은 1-3mM에서 prodigiosin의 생합성을 대조군보다 20-40% 정도 증가시켰고, 특히 5mM의 농도에서는 최대 122% 증가시켰으나, 20-30mM에서 prodigiosin의 생합성을 50-90% 정도 감소시켰다. 한편, 혐기성과 호기성 조건의 피루브산과 $\alpha$-케토부티르산은 호기성 조건의 글리옥실산과 함께 조사한 모든 농도(0.5-30mM)에서 prodigiosin이 생성되지 않았으며 또한, 혐기성 조건하에서 높은 농도(20mM 이상)의 글리옥실산은 S. marcescens의 성장을 현저하게 억제시켰다. 이러한 결과들로부터 글리옥실산은 피루브산과 $\alpha$-케토부티르산과는 다르게 낮은 농도(1-5mM)에서는 S. marcescens의 1, 2차 대사물질로 작용하여 prodigiosin 생합성을 증가시키지만, 높은 온도(20mM 이상)에서는 S. marcescens의 성장을 억제시켜 2차 대사물질인 prodigiosin의 생합성도 억제된다고 사료된다.

• 한국농공학회논문집
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• 제52권5호
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• pp.47-52
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• 2010

The purpose of this study is to investigate characteristics of total phosphorus (TP) and phosphate phosphorous ($PO_4$-P) concentrations in ponded water and redox potential (Eh) in paddy soil during the growing season. The TP and $PO_4$-P concentrations showed twice peak values after basal dressing and tillering fertilization. The ratio of $PO_4$-P to TP showed low values (0.07~0.18), indicating that most of phosphorus is particlulate. The $PO_4$-P concentrations significantly decreased with dissolved oxygen (DO) concentrations. The Eh showed high values (179~636 mV) under non-ponded aerobic condition, but low values (74~112 mV) under ponded anaerobic condition The TP and $PO_4$-P concentrations in ponded water increased shortly after tillering fertilization even if phosphorus was not applied. This may be due to the release of dissolved phosphorus from the bottom sediment and its associated algal and water flea blooms under anaerobic condition. Therefore, proper water management should be needed shortly after tillering fertilization.