• 한국유기농업학회지
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• 제20권3호
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• pp.369-383
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• 2012

사육밀도를 달리 했을 때 지렁이 개체군의 생체량 증가를 위한 최적 사육밀도를 추정하려고 하였다. 실험결과를 요약하면 다음과 같다. 1. 사육밀도 S-2과 S-3에서 상대증체량, 생체중 증가율과 유기물 전환효율이 높은 값을 나타내어, 지렁이 개체군의 최대 생체량을 얻기 위한 최적 사육밀도로 추정되었다. 이를 지렁이 생체중과 먹이량의 비율로 나타내면 1:32-1:48의 범위였다. 2. 사육밀도 S-1(1:16)에서 모든 조사시기의 분립생산량이 유의하게 많았고 분립비율도 유의하게 높았다($$P{\leq_-}0.05$$). 3. 사육밀도 S-3(1:48)에서 지렁이 생체중당 난포수와 분립생산량이 가장 많았다($$P{\leq_-}0.05$$). 4. 사육밀도가 높아지고 사육기간이 길어짐에 따라 분립의 전 질소함량, 유효인산함량, 양이온치환능력(CEC) 및 양이온 함량이 증가되는 경향이었다. 5. 유기농업에서 지렁이 분립은 상토 재와 토양개량제 및 작물보호를 위한 농자재로서 잠재적 유용성은 매우 높다고 판단된다.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1849-1855
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• 2006

It has been shown that the initial conditions of bacterial cultivation are extremely important for the successful production of hyaluronic acid (HA) by fermentation. We investigated several parameters that affect cell growth rate and the productivity and molecular weight of hyaluronic acid--i.e., agitation speed, aeration rate, culture temperature, pH, and pressure--to determine how to optimize the production of HA by Streptococcus zooepidemicus on an industrial scale. Using a 30-1 jar fermentor under laboratory conditions, we achieved maximum HA productivity and biomass when the agitation speed and aeration rate were increased simultaneously. By shifting the temperature downward from 35$^{\circ}C$ to 32$^{\circ}C$ at key levels of cell growth during the fermentation process, we were able to obtain HA with a molecular weight of $2.8{\times}10^6$ at a productivity of 5.3 g/l. Moreover, we reproduced these optimized conditions successfully in three 30-1 jar fermentors. By reproducing these conditions in a 3-$m^3$ fermentor, we were able to produce HA with a molecular weight of $2.9{\times}10^6$ at a productivity of 5.4 g/l under large-scale conditions.

• Journal of Plant Biology
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• 제26권4호
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• pp.181-190
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• 1983

Seasonal occurrence of benthic algae and changes of subtidal vegetation were studied for their species composition, diversity and biomass during 1982 and 1983 at several selected sites at Juckdo Island (38$^{\circ}$12'N, 128$^{\circ}$32'E), eastern coast of Korea. Three large brown algae which played a role in change of algal vegetation through their great biomass were investigated with regard to their seasonal growth. Large brown algae such as Undaria pinnatifida, Costaria costata, Laminaria japonica, Agarum cribrosum, Sargassum confusum and S. hornerii constitute the major portion of vegetation in this area throughout the year. Algal vegetation in spring time is characterized by dominance of species U. pinnatifida and C. costata, whereas the summer vegetation by S. confusum and S. hornerii. In autumn large brown algae are shedded and only small algae, such as Chondrus ocellatus and Grateloupia filicina, remain. The vegetation in winter is dominated by the growth of U. pinnatifida and C. costata. Monthly changes in mean length and weight of randomly collected U. pinnatifida, C. costata and S. confusum are as follows; U. pinnatifida occurs from December to June and shows their maximum growth during March (120 cm in length, 201 g/individual in wet weight), its maximum growth rate is 1.4 cm/day, 3.3 g/day in this month. The growth season of C. costata is very similar to U.pinnatifida, but their average maximum length(110 cm) and weight (106 g/ind.) are lower than U. pinnatifida. The greatest growth rate is during March (1.8 cm/day, 2.0g/day). S. confusum is present throughout the year and reaches the maximum growth (102 cm, 63g/ind.) in July. Maximum growth rate (1.5 cm/day, 1.2 g/day) occurs also during this month. U. pinnatifida and C. costata show different months of maximum growth evidently during the two year. This seems to be caused by a considerable damage to the local vegetation followed by heavy storm in February 1983.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권1호
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• pp.21-25
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• 2002

To maximize and sustain the productivity of Monascus pigments, various environmental and nutritional parameters, such as the initial moisture content, pH, inoculum size, sample size, and nutrient supplement, that influence pigment production were evaluated in solid-state cultures as follows: initial moisture content, $50\%;$ pH, 6.0; inoculum size $1\;\times\;10^4$ spore cells $(grams\;of\;dry\;solid\;substrate)^{-1};$ sample size, 300 g. All supplementary nutrients (carbon, nitrogen, and mineral sources) added has inhibitory effects on the cell growth and red pigment production. In open tray culture the maximum biomass yield and specific productivity of red pigments were 223 mg DCW $(grams\;of\;initial\;dry\;substrate)^{-1}$ and, $47.6\;OD_{500}\;(DCW\;grams)^{-1}h^h{-1}$ respectively.

• KSBB Journal
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• 제5권2호
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• pp.159-165
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• 1990

Ethanol fermentation by Scccharomyces cervisiae was carried out in the cell recycle filter system with a cheap fabric filter having a pore size of 10${\mu}$m. Maximum biomass concentrations up to 85g/1 were obtained, but in practice operational concentrations were between 50 and 80g/1. Ethanol productivity was 42g/1-hr, with an ethanol concentration of 66g/1 and an ethanol yield of over 86%. Continuous operation was possible by applying periodic backflushing. The ethanol fermentation could be carried out without difficulty at a dilution rate up to 0.8h-1 In order to obtain a high cell concentration and ethanol productivity, development of filter module with the larger filtration area is required.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.689-694
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• 2006

We investigated the potential use of various carbon sources (fructose, glucose, mannose, lactose, and glycerol) for culturing Phaeodactylum tricornutum UTEX-640 in mixotrophic and heterotrophic batch cultures. Concentrations of carbon substrates tested ranged from 0.005 M to 0.2 M. P. tricornutum did not grow heterotrophically on any of the C-sources used, but successive additions of organic carbon in mixotrophic growth mode substantially increased the biomass concentration and productivity relative to photoautotrophic controls. The maximum biomass productivities in mixotrophic cultures for glycerol, fructose, and glucose were 21.30 mg/l h, 15.80 mg/l h, and 10.20 mg/l h, respectively. These values were respectively 10-, 8-, and 5-fold higher than those obtained in the corresponding photoautotrophic control cultures. Mannose and lactose did not significantly affect microalgal growth. The biomass lipids, eicosapentaenoic acid (EPA) and pigments contents were considerably enhanced with glycerol and fructose in relation to photoautotrophic controls. The EPA content was barely affected by the sugars, but were more than 2-fold higher in glycerol-fed cultures than in photoautotrophic controls.

• 한국환경농학회지
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• 제39권3호
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• pp.204-213
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• 2020

BACKGROUND: Since the number of crops cultivated in reclaimed land is huge, it is very difficult to quantify the total crop production. Therefore, a non-destructive method for predicting crop production is needed. Salt tolerant root vegetables such as red beets and sugar beet are suitable for cultivation in reclaimed land. If their underground biomass can be predicted, it helps to estimate crop productivity. Objectives of this study are to investigate maximum leaf length and weight of red beet, sugar beet, and turnips grown in reclaimed land, and to determine optimal model with regression analysis for linear and allometric growth models. METHODS AND RESULTS: Maximum leaf length, width, and root fresh weight of red beets, sugar beets, and turnips were measured. Ten linear models and six allometric growth models were selected for estimation of root fresh weight and non-linear regression analysis was conducted. The allometric growth model, which have a variable multiplied by square of maximum leaf length and maximum leaf width, showed highest R² values of 0.67, 0.70, and 0.49 for red beets, sugar beets, and turnips, respectively. Validation results of the models for red beets and sugar beets showed the R² values of 0.63 and 0.65, respectively. However, the model for turnips showed the R² value of 0.48. The allometric growth model was suitable for estimating the root fresh weight of red beets and sugar beets, but the accuracy for turnips was relatively low. CONCLUSION: The regression models established in this study may be useful to estimate the total production of root vegetables cultivated in reclaimed land, and it will be used as a non-destructive method for prediction of crop information.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.644-648
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• 2001

The biological control potential of entomopathogenic nematodes (EPN) can be enhanced by improved culture efficiency. Optimization of the media is a key factor for improving in vitro mass production of entomopathogenic nematodes. This study reports the effect of medium concentration. The medium is a combination of carbohydrates, lipids, proteins, sats, and growth factors, on the growth of Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus liminescens. The overall optimal medium concentration for nematode recovery, hermaphrodite size, bacterial mass, infective juveniles (IJs) yield, and doubling time was 84 g/l. At this concentration rate, the doubling time of IJs production and the biomass of symbiotic bacteria was 1.6 days and 12.8 g/l, respectively. The maximum yield of $2.4{\times}{10^5}IJs/ml$ was attained within a one-generation cycle (eight days). The yield coefficient was $2.8{\times}{10^6}$ IJs/g medium, and the maximum productivity was $3.1{\times}{10^7}$ IJs per day. Medium concentration affected two independent factors, recovery and hermaphrodite size, which in turn influenced the final yield.

• 한국미생물·생명공학회지
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• 제6권4호
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• pp.155-159
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• 1978

분리된 효모에 의한 aromatic ring compound의 전환반응 실험에 앞서 phenol 자화능에 대한 환경 인자의 영향을 조사하기 위하여 phenol을 유일한 탄소원으로 사용하여 분리된 효모균을 30시간, 3$0^{\circ}C$에서 진탕배양하여 균체증식량을 측정하였다. 1) pH3.5~4.5 온도 35$^{\circ}C$에서 가장 자화능이 우수하였으며 phenol의 처음 농도 1000ppm 까지 는 쉽게 이용할 수 있었고 2000ppm에서는 5 일간 배양시켰을 때 비로소 균체증식이 나타났다. 2) pH 5.0, 배양온도 3$0^{\circ}C$에서 본 균의 maximum specific growth rate는 0.27hr-1 이었으며, phenol 을 1000ppm씩 단계적으로 첨가하면서 phenol 소비율에 대한 균체수율 정수 Y값을 구한 결과 Y=3.2였다. 3) Yeast extract를 필수영양원으로 첨가할 때 0.005~0.01% 농도에서 가장 효과적이었으며, 또 산화환원소 효소 조해제인 HgCl$_2$, phenylhydrazine 을 명명 $10^{-5}$M, $10^{-3}$M을 배지내에 첨가하면 분리된 효모균의 증식을 거의 볼 수 없었다. 4) Phenol의 자화에 명종 실소원의 효과를 비교 해 본 결과 urea가 가장 효과적이었고, 이 효모균은 phenol 외에 catechol, resorcinol, benzidine 을 자화할 수 있다

• 한국해양바이오학회지
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• 제8권1호
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• pp.18-23
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• 2016

It is important to design photobioreactor by cheap material for economical microalgal biomass production. In this study, two types of marine photobioreactors (MPBR), made by either polyvinyl chloride (MPBR-PVC) or high density poly ethylene (MPBR-HDPE), are used and performance of these were compared. Tetraselmis sp. KCTC 12236BP is a green marine alga that isolated from Ganghwa Island, Korea, and the strain was used for marine cultivations using MPBR-PVC and MPBR-HDPE. The cultivations were performed three times in the spring season of 2012 using MPBR-PVC and of 2013 using MPBR-HDPE in the coastal area of Young Heung Island. As the results, MPBR-PVC shows higher biomass productivities than MPBR-HDPE, due to its high light transmittance. In the cultivations using MPBR-PVC, the average sea water temperature was $11.5^{\circ}C$ during the first experiment and $16.5^{\circ}C$ during the second and third experiments. Average light intensities during three times for experiments were 407.5, 268.1 and $273.0{\mu}{\cdot}E{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. The maximum fresh cell weight and average biomass productivity were $1.2g{\cdot}L^{-1}$ and $0.12g{\cdot}L^{-1}{\cdot}day^{-1}$. These results showed that Tetraselmis sp. KCTC12236BP were adapted well with the environmental conditions from ocean, and grow in the MPBR-PVC and MPBR-HDPE.