• 한국식품과학회지
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• 제30권3호
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• pp.660-664
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• 1998

식염용액에서 휴지미생물(non-growing microorganisms)의 사멸현상과 식염용액에서 미생물의 보호작용이 있다고 알려진 물질의 작용을 시험하였다. L. mesenteroides LA10, S. aureus B3l와 E. coli B34를 완충용액으로 제조한 0, 10, 20, 30%의 식염용액에서 배양하였을 때 각각 pH 6, 7, 5 부근에서 가장 높은 생존율을 나타내었고, 이 pH로부터 산성 또는 염기성쪽으로 변화시키거나 식염농도가 증가할 수록 생존율이 감소하였다. 젖산균 5종과 일반세균 9종 및 효모 2종의 균주를 pH 5, 6, 7로 조절한 10% 식염용액에서 실험해 본 결과 식염에 내성이 강한 pH는 미생물마다 달라 이는 균주의 특성에 속하는 것으로 사료되며 그람양성균이 그람음성균에 비해 식염내성이 높았으며 그람양성균 중에서도 젖산균이 식염에 대한 내성이 두드러지게 컸고 일반세균에서는 S. aureus가 큰 것으로 나타났다. 식염농도의 영향은 물론 pH가 식염용액에서 미생물의 사멸에 큰 영향을 미치는 것으로 나타났다. 식염의 미생물 생육저해작용으로부터 미생물을 보호한다고 알려진 물질들의 보호작용은 관찰되지 않았다.

• Journal of Microbiology and Biotechnology
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• 제19권1호
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• pp.65-71
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• 2009

Microbial oxidoreductive systems have been widely used in asymmetric syntheses of optically active alcohols. However, when reused in multi-batch reaction, the catalytic efficiency and sustainability of non-growing cells usually decreased because of continuous consumption of required cofactors during the reaction process. A novel method for NADPH regeneration in cells was proposed by using pentose metabolism in microorganisms. Addition of D-xylose, L-arabinose, or D-ribose to the reaction significantly improved the conversion efficiency of deracemization of racemic 1-phenyl-1,2-ethanediol to (S)-isomer by Candida parapsilosis cells already used once, which afforded the product with high optical purity over 97%e.e. in high yield over 85% under an increased substrate concentration of 15 g/l. Compared with reactions without xylose, xylose added to multi-batch reactions had no influence on the activity of the enzyme catalyzing the key step in deracemization, but performed a promoting effect on the recovery of the metabolic activity of the non-growing cells with its consumption in each batch. The detection of activities of xylose reductase and xylitol dehydrogenase from cell-free extract of C. parapsilosis made xylose metabolism feasible in cells, and the depression of the pentose phosphate pathway inhibitor to this reaction further indicated that xylose facilitated the NADPH-required deracemization through the pentose phosphate pathway in C. parapsilosis. moreover, by investigating the cofactor pool, the xylose addition in reaction batches giving more NADPH, compared with those without xylose, suggested that the higher catalytic efficiency and sustainability of C. parapsilosis non-growing cells had resulted from xylose metabolism recycling NADPH for the deracemization.

• Journal of Microbiology and Biotechnology
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• 제27권10호
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• pp.1790-1797
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• 2017

In the present study, we demonstrate that the growth of salt-stressed pepper plants is improved by inoculation with plant growth-promoting rhizobacteria (PGPR). Three PGPR strains (Microbacterium oleivorans KNUC7074, Brevibacterium iodinum KNUC7183, and Rhizobium massiliae KNUC7586) were isolated from the rhizosphere of pepper plants growing in saline soil, and pepper plants inoculated with these PGPR strains exhibited significantly greater plant height, fresh weight, dry weight, and total chlorophyll content than non-inoculated plants. In addition, salt-stressed pepper plants that were inoculated with B. iodinum KNUC7183 and R. massiliae KNUC7586 possessed significantly different total soluble sugar and proline contents from non-inoculated controls, and the activity of several antioxidant enzymes (ascorbate peroxidase, guaiacol peroxidase, and catalase) was also elevated in PGPR-treated plants under salt stress. Overall, these results suggest that the inoculation of pepper plants with M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586 can alleviate the harmful effects of salt stress on plant growth.

• 상하수도학회지
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• 제20권5호
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• pp.755-761
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• 2006

Recently, there is growing interest in ultraviolet (UV) irradiation as a disinfection technic in drinking water production due to its effectiveness to inactivate microorganisms such as Crytosporidium parvum without forming disinfection byproducts. However, UV disinfection is known for its drawback such as photoreactivation. Despite many works concerning the photoreactivation, most of works were focused on indicator or non pathogenic microorganisms. The objective of this study is to examine the photoreactivation of Pseudomonas aeruginosa which is an opportunistic pathogen as UV radiation by LP and MP UV lamp was applied. The result showed that P. aeruginosa had high photo repair efficiency regardless of the type of UV irradiation. Both of the effective log repair values of LP and MP UV irradiation were found approximately 2.6 log. In addition, photo repaired P. aeruginosa was not significantly different in forming biofilm in comparison with non treated P. aeruginosa.

• 한국환경농학회지
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• 제31권1호
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• pp.52-59
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• 2012

BACKGROUND: Cultivation of genetically modified(GM) crops rapidly has increased in the global agricultural area. Among those, herbicide resistant GM crops are reported to have occupied 89.3 million hectares in 2010. However, cultivation of GM crops in the field evoked the concern of the possibility of gene transfer from transgenic plant into soil microorganisms. In our present study, we have assessed the effects of herbicide-resistant GM Chinese cabbage on the surrounding soil microbial community. METHODS AND RESULTS: The effects of a herbicide-resistant genetically modified (GM) Chinese cabbage on the soil microbial community in its field of growth were assessed using a conventional culture technique and also culture-independent molecular methods. Three replicate field plots were planted with a single GM and four non-GM Chinese cabbages (these included a non-GM counterpart). The soils around these plants were compared using colony counting, denaturing gradient gel electrophoresis and a species diversity index assessment during the growing periods. The bacterial, fungal and actinomycetes population densities of the GM Chinese cabbage soils were found to be within the range of those of the non-GM Chinese cabbage soils. The DGGE banding patterns of the GM and non-GM soils were also similar, suggesting that the bacterial community structures were stable within a given month and were unaffected by the presence of a GM plant. The similarities of the bacterial species diversity indices were consistent with this finding. CONCLUSION: These results indicate that soil microbial communities are unaffected by the cultivation of herbicide-resistant GM Chinese cabbage within the experimental time frame.

• 한국균학회지
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• 제34권2호
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• pp.88-91
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• 2006

가평에서 낮은 생산성을 보이는 저온성 품종과 고온성 품종의 균사상태 및 골목 표면에 형성된 해균에 대한 조사를 시도했다. 순수배지에서의 균사생장력을 조사한 결과, 저온성 균주는 분리균에 비해 보존균의 생장력이 1.1% 정도 떨어지는 것으로 나타났으며, 고온성 균주는 분리균의 생장력이 보존균의 생장력에 비해 8.0% 정도 떨어지는 것으로 나타났다. 톱밥배지에서의 균사생장력을 조사한 결과, 고온성 분리균은 보존균에 비해 10.8%정도 생장력이 떨어졌으며, 저온성 분리균은 보존균에 비해 25.1% 떨어지는 것으로 나타났다. 중량감소율 조사결과, 고온성 분리균은 보존균에 비해 20.1% 정도 중량감소율이 낮았으며, 저온성 분리균도 보존균에 비해 19.0%정도 낮은 것으로 나타났다. 무처리에 비해서는 고온성 보존균이 107.0%, 고온성 분리균이 49.5%, 저온성 보존균이 85.4%,저온성 분리균이 50.0% 더 감소된 것으로 나타났다. 대치배양한 결과, 고온성 분리균과 저온성 분리균 모두 각각의 해당 보존균들과 동일한 균주임을 확인할 수 있었다. 또한 골목에서 검은혹버섯(Hypoxylon truncatum), 구름버섯(Coriolus versicolor), 기와층버섯(Inonotus xeranticus), 삼색도장버섯(Daedaleopsis tricolor), 이중껍질버섯(Graphostroma platystoma), 점균류(Myxomycetes) 2종, 푸른 곰팡이(Trichoderma sp.), Hypoxylon fragiforme, Hypoxylon howeianum, Nitschkia confertula 등 총 11종의 해균이 발견되었으며, 골목들의 상태는 좋지 않았다.

• 한국환경보건학회지
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• 제35권6호
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• pp.433-446
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• 2009

Pharmaceuticals in the aquatic environment are trace contaminants of growing importance in environmental health due to their physiologically active nature. Pharmaceuticals could affect non-target species and might eventually damage sustainability of susceptible populations in the ecosystem. Potentials for health consequences among susceptible human population cannot be ruled out since long-term exposure to cocktails of pharmaceuticals, which might be present in drinking water, is possible. Selection of antibiotic resistant microorganisms is of another concern. In order to understand, and if needed, to properly address the environmental health issues of pharmaceutical residues, knowledge gaps need to be filled. Knowledge gaps exist in many important areas such as prioritization of target pharmaceuticals for further risk studies, occurrence patterns in different environments, chronic toxicities, and toxicities of pharmaceutical mixtures. Appropriate treatment technologies for drinking water and wastewater could be developed when they are deemed necessary. One of the simplest, yet most efficient measures that could be undertaken is to implement a return program for unused or expired drugs. In addition, implementation of environmental risk assessment frameworks for pharmaceuticals would make it possible to efficiently manage potential environmental health problems associated with pharmaceutical residues in the environment.

• Asian-Australasian Journal of Animal Sciences
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• 제31권12호
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• pp.1890-1896
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• 2018

Objective: As the climate changes, it influences ruminant's feed intake, nutrient digestibility, rumen methane production and emission. This experiment aimed to evaluate the effect of feeding Sweet grass (Pennisetum purpureum cv. Mahasarakham; SG) as a new source of good quality forage to improve feed utilization efficiency and to mitigate rumen methane production and emission. Methods: Four, growing crossbred of Holstein Friesian heifers, 14 months old, were arranged in a $4{\times}4$ Latin square design to receive four dietary treatments. Treatment 1 (T1) was rice straw (RS) fed on ad libitum with 1.0% body weight (BW) of concentrate (C) supplementation (RS/1.0C). Treatment 2 (T2) and treatment 3 (T3) were SG, fed on ad libitum with 1.0% and 0.5% BW of concentrate supplementation, respectively (SG/1.0C and SG/0.5C, respectively). Treatment 4 (T4) was total Sweet grass fed on ad libitum basis with non-concentrate supplementation (TSG). Results: The results revealed that roughage and total feed intake were increased with SG when compared to RS (p<0.01) while TSG was like RS/1.0C treatment. Digestibility of nutrients, nutrients intake, total volatile fatty acids (VFAs), rumen microorganisms were the highest and CH4 was the lowest in the heifers that received SG/1.0C (p<0.01). Total dry matter (DM) feed intake, digestibility and intake of nutrients, total VFAs, $NH_3-N$, bacterial and fungal population of animals receiving SG/0.5C were higher than those fed on RS/1.0C. Reducing of concentrate supplementation with SG as a roughage source increased $NH_3-N$, acetic acid, and fungal populations, but it decreased propionic acid and protozoal populations (p<0.05). However, ruminal pH and blood urea nitrogen were not affected by the dietary treatments (p>0.05). Conclusion: As the results, SG could be a good forage to improve rumen fermentation, decrease methane production and reduced the level of concentrate supplementation for growing ruminants in the tropics especially under global climate change.

• 생태와환경
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• 제37권1호통권106호
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• pp.112-121
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• 2004

이 연구에서는 하수처리수를 농업용수로써 재이용시 발생할 수 있는 위생문제를 검토하기 위해 하천수, biofilter 유출수, 그리고 UV소독수를 관개한 벼재배 실험포트에서 지표미생물의 밀도변화를 조사하였다. 우리나라 하수처리장 유출수 수질기준을 살펴보면, USEPA에서 정하고 있는 농업용수 재이용 수질기준 항목인 $BOD_5$와 SS의 수질기준은 만족시키지만, 대장균의 경우추가적인 처리가 필요한 것으로 나타났다. 벼 식재 직후인 5월과 6월의 경우 관개 후 24시간 동안의 평균밀도가 $10^2{\sim}10^4$의 범위에서 관개용수의 밀도와 상관없이 지표미생물의 밀도변화는 크게 나타나지 않았다. 이 시기에는 기비와 추비로 인해 미생물의 성장에 필요한 영양물질, 교란된 저질의 높은 미생물 밀도 등에 영향을 받고 논의 벼 생육생태가 덜 성숙되었기 때문으로 판단된다. 그러나 7월과 8월은 처리구별로 밀도차이가 컸고 24시간 동안 변화폭도 컸으며, 관개용수 미생물밀도에 영향도 일부 나타났다. 실험기간동안 지표미생물의 밀도를 관개용수별로 분산 분석한 결과, UV소독 후 관개한 경우가 하천수와 biofilter 유출수를 사용한 경우보다 낮은 밀도를 나타내었다. 실제 논농사가 이루어지고 있던 양평군의 하천관개 논과 여주군의 지하수관개 논의시료분석에서 지표미생물 밀도는 FC, E. coli밀도가 TC밀도보다 크게 낮았으며, 시기별로 밀도의 차이가 있으나, TC, FC, 그리고 E. coli의 평균밀도가 약 4,000, 400,300 MPN/100mL범위를 나타내었다. TC의 밀도는 본 실험포트 실험과 유사한 범위이었으며, FC와 E. coli는 실험포트에서 초기 경운시 사용된 biofilter 유출수의 영향으로 실제 논보다 높은 값이었다. 이앙기 때에는 특별히 논 표면수와 신체접촉이 많은 점을 고려할 때 하수처리수만을 관개하여 이앙준비를 하는 것보다 하수처리수를 보조관개용수로 사용하는 것이 보다 안전할 것으로 판단된다. 하수처리수를 농업용수로 재이용할 경우 하수처리수를 관개용수로 직접 이용하기보다는 UV소독으로 보건 위생학적으로 높은 안정성을 확보할 수 있으며 하수처리수재이용 수질기준에도 적합할 수 있을 것이다. 그러나 벼의 생육에 영향을 줄 수 있는 영양물질과다로 인한 도복문제, 하수처리수에 존재할 수 있는 독성물질에 의한 영향 등 하수처리수를 관개강수로 이용하는 데에는 종합적이고 과학적인 고찰이 필요하며, 본연구의 결과는 하수처리수를 농업적으로 이용할 경우 공공의 보건 ·위생적인 안전을 확보하기 위한 기초연구로서의 성격을 갖는다고 할 수 있다.

• 한국토양비료학회지
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• 제17권4호
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• pp.399-405
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• 1984

논토양(土壤)에 볏짚을 시용(施用)하고 투수조건하(透水條件下)에서 수도재배중(水稻栽培中), 토양중(土壤中) 질소고정(窒素固定)에 관여(關與)하는 미생물(微生物)의 소장(消長)과 질소고정능(窒素固定能)을 조사분석(調査分析)한 결과(結果)는 다음과 같다. Azotobacter는 경시적(經時的)으로 약간 증가(增加)하고 볏짚시용(施用)으로 균수(菌數)가 낮아지는 경향(傾向)이었다. Clostridia 는 경시적(經時的)으로 크게 증감(增減)되지 않았다. Blue green algae는 출수기(出穗期)까지 증가(增加)하다 감소(減少)했으며 볏짚시용(施用)으로 균수(菌數)가 증가(增加)하는 경향(傾向)이다. 질소무황세균(窒素無黃細菌)은 재배기간중(栽培其間中) 거의 검출(檢出)되지 않았고 Yeast는 경시적(經時的)으로 약간 증가(增加)하는 경향(傾向)이었다. 질소고정미생물(窒素固定微生物)의 균수(菌數)가 증가(增加)되면 acetylene환원력(還元力)도 증대(增大)되었으며 수도재배기간중(水稻栽培其間中) 질소고정력(窒素固定力)은 0.2~0.4kg/10a이었다. 수도무재배구(水稻無栽培區)에서 질소(窒素)의 고정력(固定力)은 볏짚시용(施用)으로 약간 증가(增加)되었으나 투수(透水)의 효과(效果)는 뚜렷하지 않다.