• Journal of Microbiology and Biotechnology
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• 제10권3호
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• pp.333-337
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• 2000

An oil-degrading yeast, Yarrowia lipolytica 180, exhibits interesting cell surface characteristics under the growth on hydrocarbons. An electron microscopic study revealed that the cells grown on crude oil showed protrusions on the cell surface, and thicker periplasmic space and cell wall than the cell surface, and thicker periplasmic space and cell wall than the cells grown on glucose. Y. lipolytica cells lost its cell hydrophobicity after pronase(0.1 mg/ml) treatment. The strain produced two types of emulsifying materials during the growth on hydrocarbons; one was water-soluble extracellular materials and the other was cell wall-associated materials. Both emulsifying materials at lower concentration (0.12%) enhanced the oil-degrading activity of Moraxella sp. K12-7, which had medium emulsifying activity and negative cell hydrophobicity; however, it inhibited the oil-degrading activity of Pseudomunas sp. K12-5, which had medium emulsifying activity and cell hydrophobicity. These results suggest that the oil-degrading activity of Y. lipolytica 180 is closely associated with cell surface structure, and that a finely controlled application of Y.lipolytica 180 in combination with other oil-degrading microorganisms showed a possible enhancing efficiency of oil degradation.

• Journal of Microbiology
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• 제37권3호
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• pp.128-135
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• 1999

Among oil-degrading microorganisms isolated from oil-polluted industrial areas, one yeast strain showed high degradation activity of aliphatic hydrocarbons. From the analyses of 18S rRNA sequences, fatty acid, coenzyme Q system, G+C content of DNA, and biochemical characteristics, the strain was identified as Yarrowia lipolytica 180. Y. lipolytica 180 degraded 94% of aliphatic hydrocarbons in minimal salts medium containing 0.2% (v/v) of Arabian light crude oil within 3 days at 25$^{\circ}C$. Optimal growth conditions for temperature, pH, NaCl concentration, and crude oil concentration were 30$^{\circ}C$, pH 5-7, 1%, and 2% (v/v), respectively. Y. lipolytica 180 reduced surface tension when cultured on hydrocarbon substrates (1%, v/v), and the measured values of the surface tension were in the range of 51 to 57 dynes/cm. Both the cell free culture broth and cell debris of Y. lipolytica 180 were capable of emulsifying 2% (v/v) crude oil by itself. They were also capable of degrading crude oil (2%). The strain showed a cell surface hydrophobicity higher than 90%, which did not require hydrocarbon substrates for its induction. These results suggest that Y. lipolytica has high oil-degrading activity through its high emulsifying activity and cell hydrophobicity, and further indicate that the cell surface is responsible for the metabolism of aliphatic hydrocarbons.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.203.4-203
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• 2005

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1170-1177
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• 2005

Terminal-restriction fragment length polymorphism (T-RFLP) analysis was used to monitor inoculated oil-degrading microorganisms during bioremedial treatability tests. A pair of universal primers, fluorescently labeled 521F and 1392R, was employed to amplify small subunit rDNA in order to simultaneously detect two bacterial strains, Corynebacterium sp. IC10 and Sphingomonas sp. KH3-2, and a yeast strain, Yarrowia lipolytica 180. Digestion of the 5'-end fluorescence/labeled PCR products with HhaI produced specific terminal-restriction fragments (T-RFs) of 185 and 442 bases, corresponding to Corynebacterium sp. IC10 and Y. lipolytica 180, respectively. The enzyme NruI produced a specific T-RF of 338 bases for Sphingomonas sp. KH3-2. The detection limit for oildegrading microorganisms that were inoculated into natural environments was determined to be $0.01\%$ of the total microbial count, regardless of the background environment. When three oil-degrading microorganisms were released into oil-contaminated sand microenvironments, strains IC10 and 180 survived for 35 days after inoculation, whereas strain KH3-2 was detected at 8 days, but not at 35 days. This result implies that T-RFLP could be a useful tool for monitoring the survival and relative abundance of specific microbial strains inoculated into contaminated environments.

• KSBB Journal
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• 제14권4호
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• pp.503-510
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• 1999

한국해양연구소에서 분양받은 유류분해효모 Yarrowia lipolytica CL180를 이용하여 경유로 오염된 토양에 대한 질소원, 인원 aeration rate, 그리고 균체량에 따른 영향을 조사하였다. 실험결과 질소원이 미생물 성장의 limiting factor로 작용하였으며, 다양한 비(C : N =100 : 5, 100 : 10, 100 : 15, 100 : 20 mg/kg soil)의 질소원을 첨가한 결과 C : N의 비(w/w)가 100 : 5일 때 가장 우수한 분해율과 균체수를 나타내었다. 질소원이 이 비율 이상으로 첨가되었을 때 분해율과 균체수가 낮게 나타났으며 이는 암모니아의 독성으로 인한 영향으로 사료된다. 그러나 인원과 통기에 따른 경유분해율의 변화는 없었으며 질소원이 첨가된 soil column에서는 7일이 경과된 후 약 50%의 경유잔류량을 나타내었다. 잔류경유를 제거하기 위하여 최초 접종량과 동일한 양의 균주를 접종하였으나 일정기간의 경과후에도 경유잔류량은 거의 변화가 없었다. 이는 경유의 토양 흡착 때문으로 사료된다.