• Asian-Australasian Journal of Animal Sciences
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• 제27권6호
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• pp.818-824
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• 2014

The nutrient composition of pasture, voluntary intake and digestibility of diet ingested by goats grazing on an introduced Leymus chinensis pasture were measured across spring (May), summer (July), autumn (October) and winter (March). In each season, 12 Inner Mongolian Cashmere goats (6 wethers and 6 does with an average live weight of $22.2{\pm}1.3$ kg and $19.5{\pm}0.8$ kg, respectively) were used to graze on a 2 hectares size paddock. Diet selection was observed and the plant parts selected by grazing goats and whole plant L. chinensis were sampled simultaneously. The alkane pair $C_{32}:C_{33}$ and $C_{36}$ were used to estimate intake and digestibility, respectively. The results showed that the plant parts selected by goats had higher crude protein (CP) and lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) than the whole plant, especially in the autumn and winter. The voluntary intake of dry matter (DM), CP, ADF, NDF, and metabolizable energy (ME) by goats was highest in summer (p<0.05). The goats ingested more CP, ME, and less ADF in spring than in autumn (p<0.05). The intakes of DM, CP, and ME were lowest in winter (p<0.05). There were significant differences in nutrient intake between wethers and does in each season, except for the ADF and ME intake per metabolic weight ($LW^{0.75}$). The nutrient digestibilities were higher in spring and summer, and decreased significantly during the autumn and winter (p<0.05). Goats, especially wethers, had a relative constant NDF digestibility across seasons, however, the apparent digestibility of CP in both wethers and does, decreased to negative values in winter. The grazing goats experienced relatively sufficient nutrients supply in spring and summer, and a severe deficiency of CP and ME in winter.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1966-1974
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• 2008

A typical tropical soil from the northeast of Brazil, where an important terrestrial oil field is located, was accidentally contaminated with a mixture of oil and saline production water. To study the bioremediation potential in this area, molecular methods based on PCR-DGGE were used to determine the diversity of the bacterial communities in bulk and in contaminated soils. Bacterial fingerprints revealed that the bacterial communities were affected by the presence of the mixture of oil and production water, and different profiles were observed when the contaminated soils were compared with the control. Halotolerant strains capable of degrading crude oil were also isolated from enrichment cultures obtained from the contaminated soil samples. Twenty-two strains showing these features were characterized genetically by amplified ribosomal DNA restriction analysis (ARDRA) and phenotypically by their colonial morphology and tolerance to high NaCl concentrations. Fifteen ARDRA groups were formed. Selected strains were analyzed by 16S rDNA sequencing, and Actinobacteria was identified as the main group found. Strains were also tested for their growth capability in the presence of different oil derivatives (hexane, dodecane, hexadecane, diesel, gasoline, toluene, naphthalene, o-xylene, and p-xylene) and different degradation profiles were observed. PCR products were obtained from 12 of the 15 ARDRA representatives when they were screened for the presence of the alkane hydroxylase gene (alkB). Members of the genera Rhodococcus and Gordonia were identified as predominant in the soil studied. These genera are usually implicated in oil degradation processes and, as such, the potential for bioremediation in this area can be considered as feasible.

• 한국의류학회지
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• 제17권4호
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• pp.511-517
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• 1993

Changes of the surface and interface tension with temperature for washing liquids and alkanes were measured by FACE surface tensiometer. Using the extended Fowkes' equation, the dispersion and polar force components of the surface tension were estimated. The results were as follows : 1. The surface tensions of washing liquids and alkanes decreased almost linearly with the increase of temperature. 2. The interface tensions of 0.25% DBS/alkane increased slowly with the increase of temperature. In the case of nonionic surfactant solutions, however, the interface tensions with alkanes varied with the number of hydrophilic ethylene oxide(EO) groups. 3. Of the surface tension of water at $20^{\circ}C$, the dispersion force component was 25.3 dyn/cm and the polar force component was 47.8 dyn/cm. As the temperature increased, both the polar and dispersion force components decreased in a similar fashion. 4. The dispersion force component of surface tension of 0.25% DBS solution was 30.0 dyn/cm, and the polar force component was 2.2 dyn/cm at $20^{\circ}C$. The two components decreased with the increase of temperature. 5. As the temperature increased, the dispersion force component of surface tension decreased and the polar force component increased significantly for 0.25% NPPG-7.5EO solution. In the case of 025% NPPG-10EO, both the dispersion and polar force components decreased slowly, but the polar force component is expected to increase from $60^{\circ}C$. However, the polar force component of surface tension decreased with the increase of temperature for 025% NPPG-15EO solution, and at the temperature higher than $60^{\circ}C$ the surface tension is expected to be composed of only dispersion force component.

• 공업화학
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• 제17권1호
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• pp.12-15
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• 2006

본 연구의 목적은 물유리에 의해 제조된 실리카 미립자의 평균입도와 입도분포에 미치는 반응조건, 용매 및 계면활성제의 영향을 조사하는 것이다. 실리카 미립자는 다양한 종류의 계면활성제와 분산용매를 사용하는 에멀젼법에 의해 제조하였다. 계면활성제로는 비이온성인 Span 20, Span 40, Span 60 및 Span 80을 사용하였으며, 분산용매로는 알킬그룹인 n-Hexane, n-Heptane, iso-Octane 및 n-Decane을 사용하였다. 실험결과에 의하면 유화교반속도에 따른 실리카 미립자의 평균 입경은 교반속도가 증가함에 따라 감소하였으며, 일정한 입경의 에멀젼을 형성하기 위한 최적의 유화교반시간은 약 6 min임을 알 수 있었다. 생성된 실리카 미립자의 평균입경은 사용된 용매의 분자량이 증가함에 따라 감소하며, 사용한 계면활성제의 hydrophobic lipophilic balance(HLB) 값이 감소함에 따라 증가하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.275-275
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• 2013

Formation and characterization of self-assembled monolayers (SAMs) on various surfaces are the essential basis for many other applications, including molecular switches, biosensors, microfluidics, and fundamental studies in surfaces and interfaces. To improve the performance at these applications, it is a key to control the quantity of each molecule in various mixed SAMs on the surface. In this study, using mixed SAM of carbamate-based hydroquinone (HQ)-PhBr and11-mercaptoundecanol, the quantitative mass spectrometric method of mixed SAM was developed based on comparison study with XPS and FT-IR methods. In addition, our method was applied to another mixed SAM of biotinylated PEG alkane thiol and 11-mercaptoundecanol for verification purpose. Time-of-flight secondary mass spectrometry (ToF-SIMS) analysis was performed to identify and quantify each molecule of mixed SAM along with principal component analysis (PCA). Since there is no matrix effect in the X-ray photoelectron spectroscopy (XPS) and Fourier transform-infrared (FT-IR) techniques, we compared ToF-SIMS results with XPS and FT-IR results. Because PCA results from ToF-SIMS analysis are well matched with XPS and FT-IR results from both mixed SAMs, we are expecting that our method will be useful to identify and quantify each molecule in various mixed SAMs.

• Applied Biological Chemistry
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• 제29권1호
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• pp.3-9
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• 1986

Alkane 효모의 유성(有性) 생활환(生活環)을 이용한 유전적 해석과 대사경로(代謝經路)에 관한 기초자료를 얻고자 토양과 오염된 치이즈에서 citric acid의 생산성이 높은 균주를 분리하여 동정하고 교잡(交雜)에 의하여 2배체(倍體) 체화(體化)하였으며, 이들의 유전적, 생화학적 및 효소학적 특성을 검토하여 다음과 같은 결과를 얻었다. Citric acid와 isocitric acid를 생산하는 CJ2, CJ7과 CJ8 균주는 Saccharomycopsis lipolytica의 교배형(交配型) A, B와 B로 각각 동정되어 교잡(交雜)과 포자형성(胞子形成)에 의하여 얻은 배수체(倍數體)의 감수분열(減數分裂) 분리를 행한바 재조합형(再組合型) 자손이 얻어졌다. 모든 균주는 glucose배지보다 n-hexadecane배지에서 재친(再親) 1배체(倍體)보다 2배체(倍體)가 citric acid를 많이 생산하였고 isocitrate Iyase의 비활성(比活性)은 n-hexadecane배지에서 생육한 세포가 glucose배지에서 생육한 세포보다 $15{\sim}20$배 높았지만 citrate synthetase의 비활성(比活性)은 탄소원에 의하여는 거의 영향을 받지 않았다. 또한 이들 효소의 비활성(比活性)과 citric acid의 생산 사이에는 균주와 배수성에 관계없이 상관관계가 적었다.

• KSBB Journal
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• 제11권6호
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• pp.654-662
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• 1996

원유에 대한 분해능이 있는 균주를 분리하고, 이들 균주의 균체생육과 유화활성 및 원유 전환율을 검토하여 4균주 즉, A54, H17, H17-1 그리고 F6 를 선멸하였다. 이들 균주중 H17-1 균주를 최종선멸하여 형태학적 빛 생화학적 그리고 생리학적 특성 을 조사한 후 Nocardia sp. H 17-1로 명명하였다. Nocardia sp. H17-1의 배양 시간에 따른 균체생육, 유화도 그리고 원유 전환율을 측정한 결과, 균체수 는 $9.1\times109 CFU/mL$었고, 유화활성과 원유 전환율 은 각각 480 unit/mL와 약 83%로서 최대치에 도달하였다. 또한, 다양한 탄화수소를 탄소원으로 이용 하였다. 원유분해를 위한 배양조건 및 환경인자의 영향을 조사한 결과 배양온도는 $^30{\circ}C$, 초발 pH는 7.0, 염분농도는 2.0%이며, 5% 이상에서는 유화활 성이 현저히 감소하였다. 원유농도는 3%, 무기염류 의 농도는 12.5 mM $NH_4N0_3$, 0.057 mM $K_2HPO_4$로 나타났다. 또한, 잔류 원유의 GC 분석 결과 CI6(n­ hexadecane) 이상의 n-alkane peak가 현저히 감소하였다.

• 미생물학회지
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• 제21권4호
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• pp.191-196
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• 1983

토양으로부터 diaminododecane 자화균 DAD2-3주를 분리하여 Coryηebacterium속으로 동정하였다. DADZ2-3의 alkane유도체에 대한 생육특성조사에서 putrescine, dodecane, laurylamine 등은 탄소원으로 이용되었으나 dod-ecanethiol, thioanisole, decanedithiol, dicyanooctane, laurylcyanide, dichlorodecane등은 이용되지 못하였으며, emulgen 첨가에 의한 diaminododecane 자화촉진 효과는 미세하였다. DAD2-3림에 의해 diaminododecane 자화시 생성되는 중간생성불은 $\alpha$-ketoglutaric acid로 동정되었다. 그러나 d diaminododecane을 탄소원 뿐만 아니라 질소원으로도 이용하었을 경우 $\alpha$-ketoglutaric acid와는 상이한 중간 생성 풍을 생성하였으며, 탄소원으로 diaminododecane 대신 glucose, putrescine, n-dodecane을 사용하였을 경우와 또한 resting cell을 이용하여 여러가지 다른 alkane유도체를 co-oxidation시키는 과정에서도 $\alpha$-ketoglutaric acid와는 상이한 생성물이 생성되었다.

• 공업화학
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• 제34권6호
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• pp.649-659
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• 2023

This study was initiated to evaluate the phosphorus (P) removal and diesel oil degradation by bacteria isolated from industrial wastewater. The bacteria isolated were identified as Bacillus sp. The P removal efficiencies by Bacillus sp. were 99% at the initial 20 mg/L P concentration. The diesel degradation efficiencies by Bacillus sp. were 86.4% at an initial 1% diesel concentration. Lipophilicity by bacteria was the highest in the log phase, whereas it was the lowest in the death phase. As the diesel was used as a carbon source, P removal efficiencies by Bacillus sp. were 68%. When glucose, acetate, and a mixture of glucose and acetate as second carbon sources were added, the diesel degradation efficiencies were 69.22%, 65.46%, and 51.46%, respectively. The diesel degradation efficiency was higher in the individual additions of glucose or acetate than in the mixture of glucose and acetate. When P concentration increased from 20 mg/L to 30 mg/L, the diesel degradation efficiency was increased by 7% from 65% to 72%, whereas when P concentration was increased from 30 mg/L to 40 mg/L, there was no increase in diesel degradation. One of the five proteins identified by proteome analysis in the 0.5% diesel-treated samples may be involved in alkane degradation and is known as the cytochrome P450 system. Also, two of the sixteen proteins identified in the 1.5% diesel-treated samples may be implicated in the fatty acid transport system and alcohol dehydrogenation.

• 생명과학회지
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• 제26권4호
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• pp.460-467
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• 2016

사상체 토착 남세균을 경상남도 합천군 합천호의 수화시료로부터 무균적으로 분리하였으며, 형태적·분자적 동정 결과 림노트릭스 속에 속하는 것으로 밝혀졌다. 따라서, 본 남세균 균주는 림노트릭스 속 KNUA012 균주로 명명하였으며, 분리균주의 최적생장 온도는 섭씨 25도였다. 지질성분 분석 결과, 에스테르 교환반응을 거치지 않고 직접 연료로 사용할 수 있는 펜타데칸(C₁₅H₃₂)과 헵타데칸(C₁₇H₃₆)과 같은 알칸들이 본 균주에 의해 광독립 영양적으로 생합성 된다는 것이 밝혀졌다. 또한 알칸 생합성에 관여하는 유전자들이 본 남세균 내에 존재하는 것을 발견하였다. 일반적인 미세조류 바이오디젤 구성성분으로 알려진 미리스트올레산(C_14:1), 팔미트산(C_16:0) 및 팔미톨레산(C_16:1) 역시 KNUA012 균주에 의해 주요 지방산 성분으로서 생산되는 것으로 확인되었다. 근사분석 결과 KNUA012 균주의 휘발성물질 함량은 86.0%였으며, 원소분석 결과 고위발열량은 19.8 MJ kg⁻¹으로 나타났다. 또한, 본 분리균주는 고부가가치 항산화물질로 알려져 있는 피코시아닌을 광독립영양적으로 21.4 mg g⁻¹의 농도로 생산할 수 있는 것을 확인하였다. 따라서, 본 연구결과는 KNUA012 균주가 미세조류 기반 바이오연료와 바이오매스 원료의 경제적인 생산에 있어 이상적인 자원이 될 수 있음을 제시하였다.