• Asian-Australasian Journal of Animal Sciences
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• 제20권9호
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• pp.1444-1452
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• 2007

An in vitro experiment was conducted to evaluate the differences in microbial activity of five faecal inocula from weaned pigs and one faecal inoculum from unweaned pigs in combination with 6 substrates. The substrates tested were negative control diet, corn, soybean meal, oligofructose (OF), ground chicory roots and a mixture (60% chicory pulp and 40% OF). The inocula used were derived from pigs fed either a corn-soy based diet without antibiotics (NCON), the NCON diet supplemented with oligofructose (OF), a mixture of chicory pulp (40%) and OF (60%) (MIX), ground chicory roots (CHR) or the NCON diet supplemented with antibiotics (PCON). The cumulative gas production measured fermentation kinetics and end products, such as total gas production, ammonia and volatile fatty acids, were also determined. Both the substrate and the inoculum significantly affected the fermentation characteristics. The cumulative gas production curve showed that different substrates caused more differences in traits of fermentation kinetics than the different inocula. Inocula of weaned pigs gave a significantly higher VFA production compared to the inoculum from unweaned animals, whilst the rate of fermentation and the total gas produced did not differ. OF showed the highest fermentation kinetics and the lowest $NH_3$, pH and OM loss compared to other substrates. It was concluded that the microbial activity was significantly affected by substrate and inoculum. Inoculum from weaned pigs had more potential for microbial fermentation of the carbohydrate ingredients and oligofructose than that of unweaned pigs. A combination of high and low polymer inulin may be more beneficial to the gut ecosystem than using high- or low-polymer inulin alone.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.437-443
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• 2003

Bioremediation technologies were applied to experimental microcosms, simulating an oil spill in a lower intertidal area. Three treatments (oil only, oil plus nutrients, and oil plus nutrients and microbial inocula) were applied, and each microcosm was repeatedly filled and eluted with seawater every 12 h to simulate tidal cycles. To minimize washing-out of the inoculum by the tidal cycles, microbial cells were primarily immobilized on diatomaceous earth before they were applied to the oiled sand. Oil degradation was monitored by gravimetric measurements, thin layer chromatography/flame ionization detector (TLC/FID) analysis, and gas chromatography (GC) analysis, and the loss of oil content was normalized to sand mass or nor-hopane. When the data were normalized to sand mass, no consistent differences were detected between nutrient-amended and nutrient/inoculum-amended microcosms, although both differed from the oil-only microcosm in respect of oil removal rate by a factor of 4 to 14. However, the data relative to nor-hopane showed a significant treatment difference between the nutrient-amended and nutrient/inoculum-treated microcosms, especially in the early phase of the treatment. The accelerating effect of inoculum treatment has hardly been reported in studies of oil bioremediation in the Tower intertidal area. The inoculum immobilized on diatomaceous earth seemed to be a very effective formulation for retaining microbial cells in association with the sand. Results of this study also suggest that interpretation of the effectiveness of bioremediation could be dependent on the selection of monitoring methods, and consequently the application of various analytical methods in combination could be a solution to overcome the limitations of oil bioremediation monitoring.

• Asian-Australasian Journal of Animal Sciences
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• 제23권12호
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• pp.1587-1593
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• 2010

Pastures of the Apennines of Central Italy contribute to feed resources of high altitude (above 1,300 m sea level) grazing systems. The objective of this study was to evaluate the effectiveness of faecal extract from the yak (Bos grunnienes) as an alternative microbial inoculum to rumen fluid for estimation of digestibility of several forage species. Forage samples produced at high altitude were tested in this study: four legumes (Lathyrus sativus L., Lotus corniculatus L., Onobrychis viciaefolia L. and Trifolium pratense L.), three forbs (Achillea millefolium L., Potentilla reptans L. and Teucrium flavum L.) and one grass (Brachipodyum pinnatum L.) were incubated with yak rumen fluid or faecal extract. A large variability in chemical composition was observed among the species collected. Rumen liquor and faecal samples were collected from adult healthy yak. The $Daisy^{II}$ incubator was used to evaluate the nutrient digestibility of forages using rumen liquor as control and faecal extract as alternative microbial inoculum sources. Filter bags containing samples of browse species were added to the four digestion vessels along with their respective inoculum and then incubated for 48 h and dry matter (DM), organic matter (OM), crude protein (CP), neutral and detergent fiber (NDF) digestibility was determined. There was a significant relationship between estimates, indicating that faecal liquor has the potential to be used instead of rumen fluid for estimation of in vitro digestibility of plants. It is concluded that the $Daisy^{II}$ incubator results are appropriate for the determination of in vitro digestibility of nutrients using faecal liquor to define the potential for adaptation of yak to new pastures.

• 대한환경공학회지
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• 제38권12호
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• pp.635-640
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• 2016

미생물연료전지(MFC)는 하 폐수내의 유기물로부터 전기를 생산할 수 있는 획기적인 기술이지만, 실용화를 위해서는 하 폐수 내의 질소를 제거할 수 있어야 한다. 본 연구에서는 두 개의 대면적 SEA (separator electrode assembly)로 구성된 평판형 외기환원전극 미생물연료전지(FA-MFC)를 이용하여 질산화 전배양의 유무와 식종원에 따른 총질소제거율을 평가하였다. 질산화 전배양 단계에서 FA-MFC의 질산화율은 식종원과는 무관하게 99% 이상을 나타냈다. 질산화 및 탈질 단계에서 300 mg-COD/L 이하의 낮은 유기물 농도에서는 전배양을 하지 않은 조건의 총질소제거율이 가장 높았다. 유기물 농도가 증가할수록 더 높은 총질소제거율을 나타냈으며, 유기물제거율은 모든 조건에서 95% 이상을 나타냈지만, 종속영양탈질에만 이용되지는 않은 것으로 판단된다. FA-MFC의 전기 발생량은 매우 낮았지만, 유기물과 질소를 동시에 제거할 수 있다는 장점이 있기 때문에 획기적인 하 폐수처리공법으로 발전시킬 수 있으리라 기대된다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.990-996
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• 2005

The effect of diets varying in level and source of nitrogen (N) and fermentable organic matter on dynamic characteristics of microbial populations in rumen liquor and their impact on substrate fermentation in vitro was studied. The diets tested were straw alone, straw+concentrate mixture and straw+urea molasses mineral block (UMMB) lick. The same diets were taken as substrates and tested on each inoculum collected from the diets. Diet had no effect on the amino acid (AA) composition of either bacteria or protozoa. Differences among the diets in intake, source of N and OM affected bacterial and protozoal characteristics in the rumen. Upper asymptote of gas production (Y$\alpha$) had a higher correlation with bacterial pool size and production rate than with protozoal pool size and production rate. Among the parameters of the gas production model, Y$\alpha$ and lag time in total gas has showed significant (p<0.01) correlation with bacterial characteristics. Though the rate constant of gas production significantly differed (p<0.01) between diet and type of straw, it was least influenced by the microbial characteristics. The regression coefficient of diet and type of straw for Y$\alpha$ indicated that the effect of diet on Y$\alpha$ was threefold higher than that of the straw. As microbial characteristics showed higher correlation with Y$\alpha$, and diet had more influence on the microbial characteristics, gas production on a straw diet could be used effectively to understand the microbial characteristics.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3726-3729
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• 2011

Biofilm formation is inevitable in a bioelectrochemical system in which microorganisms act as a sole biocatalyst. Cathodic biofilm (CBF) works as a double-edged sword in the performance of the air-cathode microbial fuel cells (MFCs). Proton and oxygen crossover through the CBF are limited by the robust structure of extracellular polymeric substances, composition of available constituents and environmental condition from which the biofilm is formed. The MFC performance in terms of power, current and coulombic efficiency is influenced by the nature and origin of CBF. Development of CBF from different ecological environment while keeping the same anode inoculums, contributes additional charge transfer resistance to the total internal resistance, with increase in coulombic efficiency at the expense of power reduction. This study demonstrates that MFC operation conditions need to be optimized on the choice of initial inoculum medium that leads to the biofilm formation on the air cathode.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.552-555
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• 2001

본 연구는 MEK, MIBK와 BTX 혼합물을 미생물 컨소시엄을 통하여 biofilter를 이용한 이 들 화합물에 대한 제거율을 파악해 봄으로써, 추후에 pilot plant scale을 설계하는 기본 변수로 활용하고자 한다. 미생물의 적응기간인 초기 2일까지의 제거효율은 변화의 폭이 다소 적었으나 3일 이후부터 급상승하여 4일 이후부터 높은 제거효율을 나타내었다. 또한, 혼합 VOCs의 유입 농도에 변화를 주어 이에 대한 biofilter의 운진시간에 따른 제거율의 변화에 있어서도 VOCs 유입에 대하여 초기에는 낮은 처리효율을 보여주었으나 1일이 경과한 후 높은 제거효율을 보였다. 본 연구에서는 처리할 VOCs 물질의 유입 농도 변화에 상관없이 높은 처리효율을 나타냈다 이는 biofilter 에 처음으로 적용한 섬유상 담체의 표면에 운전기간동안 미생물들이 지속적으로 부착되어 유입되는 VOCs 물질에 대한 적응기간을 단축시킬 수 있었던 것으로 사료된다.

• KSBB Journal
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• 제23권4호
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• pp.285-290
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• 2008

윤활유의 생분해도 평가를 위해 개발된 국제규격을 검토하고 국내에서 적용 가능한 방법을 개발하였다. OECD 301B, ISO 9439, ASTM 5864 등의 국외규격 중 윤활유의 생분해도 평가에 적용 가능한 규격은 주로 호기적 조건 및 액상배지 (aqueous medium) 상에서 생분해도를 평가하도록 규정하고 있고, 이들 규격은 공통적으로 이산화탄소 발생법 ($CO_2$ evolution test)에 근간을 두고 있다. 하수처리장 등에서 얻어진 미생물 접종원을 시험화합물과 함께 무기물이 함유된 액상배지에서 배양시키면서 시험화합물의 유기탄소가 미생물의 효소 작용에 의해 분해되고 산화되어 최종적으로 이산화탄소로 무기물화 (mineralization) 되는 바탕을 근거 하에 생분해성 윤활제품의 생분해도를 조사하였다. 배지별로 생분해도를 비교하였을 경우 ASTM 5864에서 규정된 배지성분을 이용할 경우 생분해도가 높았고, 접종원 농도를 $10^4{\sim}10^5$ CFU/mLdm로 하였을 때 생분해도가 높았다. 또한 접종원의 종류가 생분해도 평가에 미치는 영향을 검토하였다. 본 연구에서 제안된 생분해도 시험에 대한 밸리데이션 결과 국제규격에 제시된 밸리데이션 기준을 만족하는 것으로 확인되었다. 이러한 시험결과를 토대로 국내에서 적용 가능한 윤활제품의 생분해도 시험을 위한 표준작업절차를 마련하였다.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.

• Journal of Life Science
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• 제11권1호
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• pp.11-13
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• 2001

Several culture conditions affecting cellulose production by a newly isolated Acetobacter sp. A9 were examined by cultivating cells under shaking cultures. The inoculum size in the range of 1-10% (v/v) did not influence cellulose production. Maximum cellulose production was obtained with 200 rpm of agitation speed. The cells grown in the 75 ml of medium in a 250-ml conical flask produced the highest level of cellulose. The strain was able to produce cellulose at 25-3$0^{\circ}C$ with a maximum at 3$0^{\circ}C$. Cellulose production occurred at pH 4.5-7.5 with a maximum at pH6.5.