• 한국식품과학회지
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• 제29권2호
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• pp.343-347
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• 1997

Lactobacillus brevis, L. fermentum과 L. plantarum의 혼합젖산균을 사용하여 배양조건이 밀가루 용액의 발효에 미치는 영향을 살펴보았다. 온도변화에 따른 pH와 총적정산도의 변화를 살펴본 결과 pH의 감소와 총적정산도의 증가가 가장 크게 나타난 $35^{\circ}C$를 밀가루 발효의 최적온도로 선정하였다. 5L발효조에서 질소가스를 1.0 vvm으로 첨가한 혐기적 조건보다 공기를 첨가한 호기적 조건에서 총적정산도의 증가와 pH의 감소가 더 크게 나타났다. 최적 산소공급 조건을 찾기 위하여 통기량을 1.0 vvm으로 고정하고 교반속도를 달리하여 밀가루 용액의 발효한 결과 총적정산도가 가장 크게 나타난 교반속도 250 rpm에 해당되는 산소 전달속도상수 $60\;hr^{-1}$에서 최적이었다. 선정된 최적 배양조건에서 밀가루 발효액의 생산성을 높이기 위하여 반복비율을 변화시키면서 pH-stat를 이용한 반복 유가식 배양을 수행하였다. 반복비율이 증가할수록 반복 간격시간은 증가하였으나 밀가루 발효의 최대 작동시간은 감소하였다. 최적 반복비율을 결정하기 위하여 단위시간 당 배양부피 당 생산된 밀가루 발효액의 부피와 최대가동시간 동안 배양부피 당 생산된 총 밀가루 발효액의 부피를 살펴본 결과 20%의 반복비율에서 최대값을 나타내었다. 혼합젖산균을 이용한 밀가루용액의 유가식 배양에서 최적조건은 배양온도 $35^{\circ}C$, 통기량 1.0 vvm, 산소전달속도 $60\;hr^{-1}$, 반복비율 20%로 나타났다.

• 한국미생물·생명공학회지
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• 제36권3호
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• pp.233-239
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• 2008

A new approach to the solubilization of excess activated sludge by the inoculation of lactic acid bacteria was studied to reduce the amount of sludge produced in the activated sludge treatment process. Aerobic microorganism in sludge was lysed in anaerobic condition and the cytoplasmic substance eluted was utilized as a carbon source by lactic acid bacteria. On the basis of sludge solubilization efficiency, Lactobacillus brevis and Leuconostoc mesenteroides subsp mesenteroides were selected the best candidates among five kinds of Lactobacillus sp. and seven kinds of Leuconostoc sp. The sludge solubilization efficiency by heterofermentative lactic acid bacteria was more efficient than that of homofermentative bacteria. Initial value of soluble COD (sCOD) was 1050 mg/L at the initial inoculation time increased to 3070 mg/L (192% solubilization) at 96 h of the incubation time. The inoculation of lactobacillus brevis to the sludge resulted in 2824% increase in sCOD value after 96 h of incubation than the control experiment. Leuconostoc mesenteroides subsp mesenteroides showed 152% increase of solubilization and 30% increase of S-COD/T-COD on 96 h of incubation time. Considering the increase of S-COD by the inoculation of Leuconostoc sp. on 24 h, 10% inoculation of lactic acid bacteria to the sludge was most effective.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1798-1807
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• 2017

The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.

• KSBB Journal
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• 제26권5호
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• pp.365-373
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• 2011

Effective Microorganisms (EM), a fermented medium developed by Professor Higa at the University of the Ryukyus, is a mixed culture containing dozens of microorganisms which are beneficial to nature including people, animals, plants and many microbial species in environment. EM is known to contain more than 80 kinds of anaerobic or aerobic microbes including photosynthetic bacteria, lactic acid bacteria, yeast, actinomycetes, fungi and so on, with yeast, lactic acid bacteria and photosynthetic bacteria as the main species of EM. Antioxidant effect generated by the concert of complex coexistence and coprosperity among these microbes is considered to be the main source of EM benefits. Currently, EM is earning an increasing attention with applications in agriculture, forestry, animal husbandry, fisheries, environment and medicine among others. At the same time, however, a quantitative interpretation of EM system based on a mixed culture model needs efforts from biochemical engineers for efficient production and further promotion of EM. In this paper, we describe the functions of major microbes in EM and current researches and applications of EM in agriculture, forestry, animal husbandry, fisheries, environment and medicine.

• 대한의생명과학회지
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• 제29권4호
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• pp.249-255
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• 2023

Transporting clinical samples for microbiological testing requires a proper transport medium that guarantees the survival of microorganisms. Therefore, the aim of the study was to determine the ability of Amies Transport Medium (ATM) to maintain the viability of microorganisms in clinical specimens and its suitability as a transport medium for microbiological testing. This study evaluated the performance of swab provided by KS Co., Ltd. for three groups of bacteria comprising aerobic and facultative anaerobic bacteria, anaerobic bacteria, and fastidious bacteria, according to the Clinical and Laboratory Standard Institute (CLSI) 8.11.2. The ATM stability test was conducted by dividing the medium into two groups based on the product expiration date of use. All tested media, A and B (the date of manufacture and expiration date are different) showed ≥5 CFU, and there was no significant difference in the result values of Category A and Category B with different serial numbers for each test. The results of this experiment when cross-checked with the guidelines suggest that ATM is a suitable transport medium for microbiological testing, as it maintains the viability of microorganisms and is suitable for overgrowth trials. In addition, compared to the number of CFUs at the origin, the number of CFUs did not increase by more than 1 log after storage. These results have important implications for the development of transport media that can guarantee the survival of microorganisms in clinical specimens.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.385-393
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• 2003

Microbial communities were analyzed in an anaerobic/aerobic sequencing batch reactor (SBR) fed with glucose as a sole carbon source. Scanning electron microscopy (SEM) showed that tetrad or cuboidal packet bacteria dominated the microbial sludge. Quinone, slot hybridization, and 165 rRNA gene sequencing analyses showed that the Proteobacteria beta subclass and the Actinobacteria group were the main microbial species in the SBR sludge. However, according to transmission electron microscopy (TEM), the packet bacteria did not contain polyphosphate granules or glycogen inclusions, but only separate coccus-shaped bacteria contained these, suggesting that coccus-shaped bacteria accumulated polyphosphate directly and the packet bacteria played other role in the enhanced biological phosphorus removal (EBPR). Based on previous reports, the Actinobacteria group and the Proteobacteria beta subclass were very likely responsible for acid formation and polyphosphate accumulation, respectively, and their cooperation achieved the EBPR in the SBR operation which was supplied with glucose.

• Journal of Microbiology
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• 제33권4호
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• pp.273-277
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• 1995

Although trout farming is well established in Korea, very little information is available on the composition of intestinal microflora in rainbow trout (Salmo gairdnerii). In 1994, from October through November, we investigated the composition and succession of intestinal bacteria. As fish grew, total viable counts increased dramatically until 45 days after fertilization when anaerobes started to appear on the media. After this time, they increased steadily. Ten aerobic generic were identified and Gram negative bacteria constituted 85% of total isolates. Among these, Pseudomonas, Eikenella, and Alcaligenes were the three major genera. Six anaerobic genera were isolated and identified. The ratio of anaerobes to aerobes was about 1 : 1 in adult trout and the composition of genera was changed under different conditions.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2007년도 추계학술발표회
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• pp.185-185
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• 2007

20세기에 들어 산업, 군사 및 다양한 목적으로 비인화성 용매인 PCE와 TCE의 사용량이 증대하였다. 주의를 필요로 하는 물질임에도 불구하고 부주의한 사용과 보관으로 인해 토양, 퇴적토, 지하수에 심각하게 오염되었다. High-chlorinated ethenes은 호기성 박테리아의 oxygenation에 의해 분해되지 않는다. PEC및 TCE의 완전한 탈염소화는 혐기성조건에서만 관찰되어지며, 지난 10연년간의 연구에 의해서 탈염소화 혐기성 미생물의 수의 보고는 증가되었다. 혐기성 조건에서 탈염소화 미생물에 의해 PCE와 TCE는 less-chlorinated ethenes 또는 무해한 ethene으로 전환이 가능하다. 본 연구는 lactate를 electron donor로 이용해 PCE에서 ethene까지 완전히 탈염소화하는 혐기성 배양을 수행했다. PCE로 오염된 퇴적토 시료로부터 혐기성 미생물 배양을 성공했다. PCE가 ethene까지 완전히 분해되는 것이 관찰되었다. 추가적으로 혐기성 미생물 배양액에서 1,2-cis-dichloroethene (cis-DCE)와 vinyl chloride (VC)의 축적이 일어남을 관찰하였다. 혐기성 미생물 배양액에서 Dehalococcoides 16S rRNA gene sequences에 특이적으로 반응하는 primer를 이용한 DGGE를 통해 미생물 군집을 분석하였다. 결론적으로, 우리의 연구에서 PCE를 감소시키는 배양액을 배양했으며, 이 배양엑에는 Dehalococcoides sp. 존재하는 것을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.952-958
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• 2004

Of 23 psychrotrophic bacteria isolated from the west Pacific deep-sea sediments, 19 were assigned to the $\gamma$-Proteobacteria, 3 to the <$\beta$-Proteobacteria, and 1 to the Gram-positive bacteria, as determined by their 16S rDNA sequences. Ten psychrotrophs, affiliated to the Psychrobacter, Pseudoalteromonas, and Pseudomonas genera in the $\gamma$-Proteobacteria group, were screened for lipolytic bacteria. The majority of the lipolytic isolates had growth temperatures between 4-$30^\circ{C}$, and all of them were neutrophilic, aerobic, or facultatively anaerobic, and some were able to produce multiple kinds of ectohydrolytic enzymes. The deep-sea strains Psychrobacter sp. wp37 and Pseudoalteromonas sp. wp27 were chosen for further lipase production analysis. Both strains had the highest lipase production when grown at 10 to $20^\circ{C}$; their highest lipase production occurred at the late-exponential growth stage; and the majority of the enzymes were excreted to the outside of the cells. Lipases from both strains had the same optimal reaction temperature and pH (20-$30^\circ{C}$, pH 7-8) and could retain about 60% of their highest activity at $4^\circ{C}$. Furthermore, SDS-PAGE and an in-gel activity test showed that they had the same high molecular mass of about 85 kDa.

• 미생물학회지
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• 제40권2호
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• pp.94-99
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• 2004

산소의 존재 유ㆍ무 등과 같은 배양 환경의 변화에 따라 통성 혐기성 광합성 세균인 Rhodobacter sphaerodes B-230이 만들어내는 산소 유도체에 작용하는 효소의 특성을 조사한 결과 세포내 SOD는 호기적 배양에서는 초기 배양액의 pH가 7일 때, 혐기적 배양에서는pH 8일 때 활성이 높은 반면 세포외 방출 SOD는 두 배양조건에서 모두 약산성인 pH 6에서 활성이 높았다. Catalase는 두 조건 모두 중성 부근에서 최고의 활성을 보였으며, 산성 pH 부위에서는 급격히 활성이 낮아졌다. Mn-SOD의 활성 유도제인 methyl viologen을 첨가했을 때 두 조건 모두에서 성장의 저해를 보였으며, 배지에 철 이온을 첨가하여 배양 하였을 때 호기적 조건에서만 두 배 이상 활성이 증가되었다. 혐기적 조건에서는 전체적인 활성이 낮아 금속이온의 추가적인 첨가에도 더 이상 활성이 유도되지 않았다. Mn-SOD 활성 저해제인 $NaN_3$와 CuZn-SOD활성 저해제인 NaCN를 배양액에 첨가했을 때 NaCN은 두 가지 배양 조건에서 생성되는 SOD 모두를 저해하지 않았으며, $NaN_3$는 혐기적 배양조건에서만 0.3 mM 이상에서 급격한 SOD활성의 저해를 가져왔다. 따라서 Rhodobacter sphaeroides D-230도 혐기적 배양 조건에서 Mn-SOD가 생성되는 것을 확인할 수 있었으며,호기적 조건에서는 Fe-SOD가 생성되는 것을 확인할 수 있었다. Catalase의 활성도 두 가지 배양조건 모두에서 methy1 viologen에 의해 활성이 유도되었으며, NaCN와 $NaN_3$에 의해서 급격히 저해되었다.