• 한국환경과학회지
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• 제9권1호
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• pp.75-80
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• 2000

Kinetic data for the acid phase anaerobic digestion were presented in this study and the constants were determined with acid production rate and gas production rate. Process models based on continuous culture theory were used to describe the characteristics of the acid forming microorganisms and to enable further development toward utilization of the process in a more rational manner. Acid phase digestion can be separated with appropriate manipulation of hydraulic retention time in anaerobic digestion. Kinetic analysis of data from the various hydraulic retention times using a phase specific model obtained form the acid phase indicated maximum specific growth rate of 0.40/h, saturation constant of 2,000mgCOD.$\ell$, yield coefficient of 0.35 mgVSS/msCOD utilized and decay constant of 0.04/h for the acid production rate. Similar analysis of data for the gas production rate indicated maximum specific growth rate of 0.003/h, saturation constant of 2,200mgCOD/$\ell$, yield coefficient of 0.035 mgVSS/mgCOD utilized and decay constant of 0.06/h.

• Biotechnology and Bioprocess Engineering:BBE
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• 제3권1호
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• pp.15-18
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• 1998

The entanol productivity of superoxide dismutase (SOD)-deficient mutants of Saccharo-Myces cerevisiae was examined under the oxidative stress by Paraquat. It was observed that MnSOD-deficient mutant of S. cerevisiae had higher ethanol productivity than wild type or CuZnSOD-deficient yeast both in aerobic and in anaerobic culture condition. Pyruvated dehydrogenase activity decreased by 35% and alcohol dehydrogenase activity increased by 32% were observed in MnSOD-deficient yeast grown aerobically. When generating oxygen radicals by Paraquat, the ehanol productivity was increased by 40% in CuZnSOD-deficient or wild strain, resulting from increased activity of alcohol dehydrogenase and decreased a activity of pyruvate dehydrogenase. However, the addition of ascorbic acid with Paraquat returned the enzyme activities at the level of control. These results imply that SOD-deficiency in yeast strains may cause the metabolic flux to shift into anaerobic ethanol fermentation in order to avoid their oxidative damages by Paraquat.

• Journal of Animal Science and Technology
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• 제45권6호
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• pp.1019-1030
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• 2003

본 연구는 국내의 재래 반추동물인 재래산양과 한우의 장내에 서식하며 강력한 섬유소를 분해하는 혐기 곰팡이를 탐색하고 분리하여 섬유소 분해 특성을 구명하고자 실시되었다. 산양의 반추위로부터 16종과 한우의 십이지장 소화물로부터 5종의 혐기 곰팡이를 분리하여 총 21종의 혐기성 곰팡이가 분리되었다. 섬유소 분해효소의 활력을 측정하여 그 중 섬유소 분해력이 높은 4종의 곰팡이에 대하여 광학현미경에 의한 형태학적 관찰을 기초로 동정 작업을 수행하였다. NLRI-M003은 monocentric 성장형태, 구형의 포자낭, filamentous rhizoid 및 유주자의 flagella가 다수인 Neocallimastix sp., NLRI-M014는 monocentric 성장형태, 방추형의 포자낭, filamentous rhizoid 및 유주자의 flagella가 단수인 Piromyces sp.로, NLRI-T004는 monocentric 성장형태, 난형의 포자낭, filamentous rhizoid 및 유주자의 fagella 수가 다수인 Neocallimastix sp.로 각각 확인되었다. NLRI-M001은 Orpinomyces sp. 와 유사한 것으로 추측되나 지금까지 밝혀진 곰팡이 이외에 다른 밝혀지지 않은 곰팡이가 존재할 가능성이 있을 것으로 평가되어 더욱 더 세부적인 조사가 필요하다고 사료되었다. 혐기 곰팡이의 섬유소 분해 특성을 조사하기 위해 산양의 반추위로부터 분리된 NLRI-M003 혐기 곰팡이 배양액을 2% 첨가하여 혼합 반추위 미생물의 in vitro 건물 분해율을 볏짚과 filter paper를 기질로 하여 조사하였다. 모든 처리구에서 혐기 곰팡이 배양액을 첨가한 첨가구가 무첨가구에 비하여 볏짚의 경우 약 4%이상(p〈0.05) 그리고 filtre paper를 기질로 사용시 11% 이상(p〈0.001)의 분해율이 증가하였다. 또한 CMCase와 xylanase 효소의 활력도 첨가구에서 증가하였으며 특히 반추위 곰팡이는 강력한 xylanase 효소활력이 높음을 보여주었다.

• 한국초지조사료학회지
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• 제36권4호
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• pp.393-401
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• 2016

본 연구는 가축분뇨 혐기소화처리액과 클로렐라 배양액 시용이 이탈리안 라이그라스의 발아와 초기생육에 미치는 영향을 구명하기 위하여 수행하였다. 처리는 혐기소화처리액과 이를 배지로 활용하여 배양한 클로렐라 배양액의 희석 농도를 각각 25% (v/v), 50% (v/v), 75% (v/v), 100% (v/v)로 처리하였다. 초기생육의 평가를 위한 조사항목으로 발아율, 초장, 엽수, 엽폭, 엽록소함량 (SPAD) 측정, 지상부, 지하부 생체중과 건물중, T/R율, 뿌리길이 등을 조사하였다. 발아율은 클로렐라 배양액 25% 처리구에서 무처리구(지하수) 보다 높은 발아율을 나타내었다. 지상부 생육 특성(초장, 엽장, 엽수 및 엽폭)은 모든 처리구 중에서 클로렐라 배양액 50% 처리구가 가장 높았다. 엽록소 측정값(SPAD)은 무처리구의 30.7에 비해 클로렐라 배양액 50%처리구는 58.7로 가장 높은 수치를 나타내었다. 지상부 생체중은 클로렐라 배양액 처리구가 혐기소화액 보다 높았으며 50% 처리구에서 29.2 g으로 가장 높게 나타났다. 지하부 생체중은 클로렐라 배양액 처리구에서 21~27 g로 혐기소화처리액에 비하여 높았다. T/R율은 혐기소화처리액 처리구에서 0.98~1.04 (평균 0.97)로 클로렐라배양액 처리구의 0.94~1.06 (평균 1.02) 유의한 차이를 나타나지 않았다. 클로렐라 배양액 처리구가 혐기소화처리액 처리구보다 길었다. 이상의 결과에서 이탈리안 라이그라스의 지상부 및 뿌리 생육에 클로렐라 배양액의 초기 생육촉진 효과를 나타내었으며, 클로렐라 배양액의 적정 시용농도는 50%로 보여진다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.235-242
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• 2000

The purpose of this in vitro study was to evaluate the sealing ability of three sealers(Sealapex, Pulp canal sealer, AH26) used with continuous wave method using an anaerobic bacterial leakage model. 53 extracted human teeth with straight and single canals were prepared with crown-down pressureless technique using .04, .06 taper Profile(Maillefer, Swiss). Master apical file was maintained as #35 K-file. All canals of the experimental teeth were obturated with continuous wave method using System B(Analytic technology, U.S.A.) The teeth were randomly divided into three experimental groups of 15 and two control groups of 4. Experimental group 1 was obturated with Sealapex and group 2 with Pulp canal sealer, and group 3 with AH26. A dual chamber anaerobic bacterial leakage model was assembled. Brain heart infusion with yeast extract, hemin, menadion, and the chromogenic indicator bromocresol purple was used as the culture broth for Fusobacterium nucleatum(VPI 10197), The specimens were incubated in anaerobic chamber at $37^{\circ}C$ and were observed every 2 to 3 clays, The coronal leakage was evaluated through the color change of culture broth in lower chamber for 60 days. The results were as follows: 1. The incidence of bacterial leakage in group 1 (Sealapex group was 80%, 53% in group 2 (Pulp canal sealer), 27% in group 3 (AH26). 2. There were statistically significant differences in leakage scores between group 1 and group 2, and between group 1 and group 3, respectively. (P<0.05) 3. There was no significantly difference in leakage score between group 2 and group 3. (P>0 05)

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.639-644
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• 2019

Diarrhea is one of the most common infectious diseases known worldwide. However, few studies have examined anaerobic diarrhea-causing bacteria (DB), which are difficult to culture. Recent advances in molecular biology have facilitated the detection and analysis of anaerobic DB. In this study, long-term trends in anaerobic DB were evaluated in Korea. From 2010 to 2018, symptoms of diarrhea reported were analyzed among patients hospitalized at the Dankook University Hospital in Korea. Results of multiplex polymerase chain reaction based on seasonality, age, overlapping infection, and other factors in patients were evaluated. DB were detected in 38.2% of 1716 stool specimens in the duration of the study. Of the pathogens detected using this method, 49.8% (n = 405/813) were anaerobic bacteria, including Clostridioides perfringens, Campylobacter spp., Clostridioides difficile toxin B, and Aeromonas spp. Among the four anaerobic bacteria, Clostridioides perfringens was the most commonly occurring (15.5%; n = 126/813). Detection rates of Clostridioides perfringens, Clostridioides difficile toxin B, and Aeromonas spp. were 34.1% (n = 22/55), 34.9% (n = 43/126), and 40.0% (n = 38/109), respectively. The detection rate of Campylobacter spp. (32.7%; n = 37/115) was the highest in patients between 10 and 20 years of age. The detection rate of anaerobic DB showed an increase in 2018 as compared with that in 2010, and the number of events of diarrhea caused by anaerobic DB also increased in this duration. Further studies are required to devise methods that might prevent the proliferation of anaerobic DB.

• 한국수소및신에너지학회논문집
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• 제16권4호
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• pp.315-323
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• 2005

The integrated or the two-stage (dark anaerobic and photosynthetic) fermentation processes were compared for the hydrogen production using purple non-sulfur photosynthetic bacteria, Rhodopseudomonas palustris P4. Cell growth, pH changes and organic acids and bacteriochlorophyll contents were monitored during the processes. Culture broth of Rps. palustris P4 exhibited dark-red during the photosynthetic culture condition, while yellow under the anaerobic condition without light. Rps. palustris P4 grown at the photosynthetic condition evolved 0.38 and 1.33 ml $H_2$/mg-dcw during the dark and the light fermentation, respectively, which were totally 1.71 ml $H_2$/mg-dcw at the two-stage fermentation. The rate of hydrogen production using Rps. palustris P4 grown under the dark anaerobic condition was 2.76 ml $H_2$/mg-dcw which consisted of 0.46 and 2.30 ml $H_2$/mg-dcw from the dark and the photosynthetic fermentation processes, respectively. Rps. palustris P4 grown under dark anaerobic conditions produced $H_2$ 1.6 times higher than that of grown under the photosynthetic condition. However, total fermentation period of the former was 1.5 times slower than that of the latter, because the induced time of hydrogen production during the photosynthetic fermentation was 96 and 24 hours when the seed culture was the dark anaerobic and photosynthetic, respectively. The integrated fermentation process by Rps. palustris P4 produced 0.52 ml $H_2$/mg-dcw(1.01 mol $H_2$/mol glucose), which was 20% of the two-stage fermentation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

• 한국미생물·생명공학회지
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• 제13권2호
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• pp.169-172
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• 1985

Rhodopseudomonas K-7은 혐기 광조건과 호기암조건에서 glucose, xylose로 이용하면서 성 장할 수 있었는데, 종배양시 glucose를 첨가하는 것이 본 배양에서 glucose자화를 촉진시켰고, glucose 60mM 배지에서 배양한 것을 종균으로 했을 때, glucose이 용량이 가장 많았다. Glucose 60mM배지에서 배양한 것을 종균으로 했을 때, 배지의 glucose 농도가 높더라도 이용할 수 있는 glucose양은 제한되어 있었다. 혐기 광조건에서 보다는 호기 암조건에서 성장속도도 빨랐고, glucose, xylose자화량도 많았다.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.885-892
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• 2011

The bacterial communities in the intestinal tracts of earthworm were investigated by culture-dependent and -independent approaches. In total, 72 and 55 pure cultures were isolated from the intestinal tracts of earthworms under aerobic and anaerobic conditions, respectively. Aerobic bacteria were classified as Aeromonas (40%), Bacillus (37%), Photobacterium (10%), Pseudomonas (7%), and Shewanella (6%). Anaerobic bacteria were classified as Aeromonas (52%), Bacillus (27%), Shewanella (12%), Paenibacillus (5%), Clostridium (2%), and Cellulosimicrobium (2%). The dominant microorganisms were Aeromonas and Bacillus species under both aerobic and anaerobic conditions. In all, 39 DNA fragments were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. Aeromonas sp. was the dominant microorganism in feeds, intestinal tracts, and casts of earthworms. The DGGE band intensity of Aeromonas from feeds, intestinal tracts, and casts of earthworms was 12.8%, 14.7%, and 15.1%, respectively. The other strains identified were Bacillus, Clostridium, Enterobacter, Photobacterium, Pseudomonas, Shewanella, Streptomyces, uncultured Chloroflexi bacterium, and uncultured bacterium. These results suggest that PCR-DGGE analysis was more efficient than the culturedependent approach for the investigation of bacterial diversity and the identification of unculturable microorganisms.