• 한국미생물·생명공학회지
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• 제28권5호
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• pp.285-290
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• 2000

The effects of dissolved oxy-gen(DO) concentration and DO control modes on cell growth in a 4L computer-controlled bioreactor system were investigated using Phellinus linteus WI-001, a producer of protein-polysaccharides having potent anticancer activi-ties. When DO was controlled at about 20%, maximum cell concentration and specific growth rate of the strain were observed to increase 36% and 64%, respectively, as compared to the experiment performed without DO control. By adopting cascade automatic control of DO ar 20% in a mixed automatic control mode using computer-con-trolled program, 19.5g/L of maximum cell concentration was obtained. These results showed that the mixed auto-matic control mode was the effective method for enhancing cell growth of the shear sensitive Phellinus linteus.

• 한국대기환경학회지
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• 제28권4호
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• pp.423-434
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• 2012

This study was carried out to develop for the emission factor of greenhouse gas (GHG) from medium and smallscaled incineration facility using RPF which is considering as a part of renewable energy in UNFCC. The actual concentration of the exhaust gas and the fuel composition of RPF were measured for the calculation of GHG emission factor in RPF incinerators, and were compared with the IPCC guideline. The $CO_2$ and $N_2O$ emission factors by the actual concentration of exhaust gas were $2.3575{\pm}1.0070tCO_2/tRPF$ and $0.0014{\pm}0.0014tN_2O/tRPF$ respectively. Also, $CO_2$ emission factor by the RPF composition was $2.7057{\pm}0.0540tCO_2/tRPF$. The GHG emission factor per energy by the actual concentration was $83.0867{\pm}26.0346tCO_2e/TJ$ which showed higher consistency with the GHG emission factor ($80.3967tCO_2e/TJ$) of waste plastic in the IPCC guideline (2006b). The $CO_2$ and $N_2O$ emission factor calculated in this study is considered as a meaningful data for GHG emission factor of RPF incineration facility because of not being developed in ROK.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.267-270
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• 2000

이차대사산물의 생산에 영향을 미치는 인자 중 통기성의 조절을 통한 Monascus 적색색소의 생산을 증가 시켰다. 높은 산소공급조절은 균체량을 증가 시켰으며, 낮은 산소공급조절은 고농도의 적색색소를 생산하였다. 따라서, 산소 공급량의 조절을 통하여 적색색소 생합성 과정을 활성화 시킬 수 있다.

• Journal of Microbiology and Biotechnology
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• 제12권4호
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• pp.683-686
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• 2002

To achieve optimum operation of a thermophilic aerobic digestion (TAD) process for waste activated sludge (WAS), TAD experiments using Bacillus stearothermophilus (ATCC 31197) were carried out to investigate the optimum concentration of dissolved oxygen (DO). TAD reactors were operated at DO concentrations of 0, 1, 2, 3, 4, and 5 ppm, and the results showed that the WAS could be successfully degraded by a TAD system operated with a DO concentration of 1 ppm and above. When the TAD system with an optimum additive (2 mM Ca ion), selected from a previous study, and 1 ppm DO concentration were combined with a thermal pretreatment ($121^{\circ}C$, 10 min), the results exhibited upgraded total suspended solids and an enhanced protein degradation.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.7-10
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• 2003

Factors affecting filtration performance were investigated in a Sequencing Batch Reactor (SBR) coupled with a submerged microfiltration module. Special bioreactors for aerobic and anoxic phases, respectively, were specifically designed in order to differentiate tile effect of Dissolved oxygen (DO) from that of mixing intensity on membrane filterability. DO concentration as well as mixing intensity proved to have a major influence on the membrane performance regardless of the SBR phase. A higher DO concentration resulted in a slower rise in TMP, corresponding to less membrane fouling.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.281-288
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• 2002

Recombinant Escherichia coli strain harboring the ${\lambda}$pR-pL promotor and heterologus poly-${\beta}$-hydroxybutyrate (PHB) biosynthesis genes was used to investigate the effect of culture conditions on the efficient PHB production. The expression of phb genes was induced by a temperature upshift from $33^{\circ}C\;to\;38^{\circ}C$. The protein expression levels were measured by using two-dimensional electrophoresis, and the enzyme activities were also measured to understand the effect of culture temperature, carbon sources, and the dissolved oxygen (DO) concentration on the metabolic regulations. AcetylCoA is an important branch point for PHB production. The decrease in DO concentration lowers the citrate synthase activity, thus limit the flux toward the TCA cycle, and increase the flux for PHB production. Since NADPH is required for PHB production, the PHB production does not continue leading the overproduction of acetate and lac-tate. Based on these observations, a new operation was considered where DO concentration was changed periodically, and it was verified its usefulness for the efficient PHB production by experiments.

• The Korean Journal of Ecology
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• 제9권1호
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• pp.51-58
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• 1986

The decay rates of organic matter were investigated and the leaching rates were determined from the concentration distribution of N,P,K, Ca and Na in the soil profile at Pinus rigida stand on Mt. Gwan-ak and at Pseudosasa japonica stand on Odong-do. In order to determine the leaching rates θo/W wazs substituted with KL in Towner's equation. Decay rates were 0.191 at Pinus stand on Mt. Gwan-ak and 0.234 at Pseudosasa stan don Odong-do. Concentration distributions of N,P, K and Na in soil profiles were corresponed with Towner's model curve. Leaching rates determined from concentration distributions were 0.086, 0.079, 0.041, 0.029, 0.096 on Mt. Gwan-ak and 0.080, 0.056, 0.051, 0.008, 0.028 on Odong-do. The soil of Pseudosasa stand showed on the whole lower leaching rates than that of Pinus stand. The soil of Pseudosasa stand showing higher decay rate and lower leaching rates contained more concentration of each nutrient than that of Pinus stand.

• 한국물환경학회지
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• 제24권3호
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• pp.328-332
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• 2008

This research was about T-N removal efficiency of oxic reactor in which fixed media submerged from Membrane BNR(An+Ax+Ox) process. This experiment was implemented by using fixed media and changing DO concentration in the oxic reactor. Nitrification efficiencies of all modes were more than 98%. When no media was in the oxic reactor, T-N removal efficiency was only 47.4%, while it were shown from 60.3% to 67.4% with packed media, which indicated improved efficiency of 27~42%. The removal efficiencies of TCOD and BOD were more than 89%, 98% respectively, which could satisfy the guideline of advanced sewage reclamation by Department of Environment. When DO concentration in the packed oxic-media tank was 0.5~1.0 mg/L, T-N removal efficiency was low, which resulted from insufficient nitrification in the oxic reactor. Therefore, DO concentration of bulk solution needs to be kept more than 1.0 mg/L to induce higher nitrification efficiency in the reactor in which media was submerged. Also, the selection of DO concentration is important to prevent media from being clogged.

• 미생물학회지
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• 제35권4호
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• pp.283-288
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• 1999

본 연구를 통하여 활성슬러지중의 주요 세균인 Pseudomonas aeruginosa를 이용한 생장 특성과 세포 생장에 있어서의 고DO 농도의 영향에 대한 특성을 이용, 페수처리계의 응용성을 조사하였다. 그 결과, 본 균은 DO 농도의 증가에 따라서 세포 수율은 14배 정도 감소되는 것으로 나타났다. 또한 세포 수율의 감소는 압력의 증가에 의한 것이 아니라 DO 농도의 증가에 의한 것으로 나타났다. 이러한 사실을 바탕으로 낮은 DO 농도에서도 세포 수율의 감소효과를 가질 수 있는 변이주를 변이원 NTG 농도 100 ${\mu}$g/㎖, 30${\circ}C$, 1시간 처리하여 얻은 다음 D-cycloserine에 의한 농축배양을 통해 목적 변이주를 얻었다. 이 목적 변이주에 대한 세포 수율은 DO 농도의 증가에 따라 감소하는 경향을 나타내었으며 그 수율은 DO 농도 36 ppm에서 야생주에 비교할 때, 약 55%의 감소율을 나타내는 것으로 보아 종래의 폭기방식을 채용할 경우에도 슬러지량을 충분히 감소시킬 수 있을 것으로 기대된다.

• 한국축산시설환경학회지
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• 제7권1호
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• pp.45-56
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• 2001

The following statistics are the results of a survey that analyzed the classification of livestock area and spatial mobility based upon the number of livestock and an area of 151 towns and cities from 1975 to 1995. 1. As a results of analysis about the degree of location concentration using C.V., Korean native cattles (HanWoo) and swines are becoming more centralized while dairies and chickens are becoming decentralized. 2. 49 regions, that is 32.5%, were classified as growing regions, 30 regions (19.9%) were stagnant regions and 72 regions (47.7%) were withering regions. The classification was based upon the calculation according to the numbers of converted grown animals and growth index. Kyonggi-do and Chungchongnam-do, specifically, took up 26.6% and 24.5% of the developing regions which shows that these two regions are the dominant regions for livestock. 3. Kyongsangbuk-do and Chungchongnam-do play significant roles for overall livestock, and Chollanam-do is considering a transition from swines to Korean native cattles and Kyongsangbuk-do is shifting from Korean native cattles to swines.