• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.779-784
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• 1998

The specific growth rate and production of resting ega of the freshwater rotifer, Brachionus calyciflorus Pallas was investigated at the different temperatures ($20\~30^{\circ}C$). The rotifer was cultured in 250 ml flask and fed on concentrated freshwater Chlorella. Specific growth rate of B. calyciflorus showed higher rate at higher temperature, but maximum density was observed higher at lower temperature, expect at $20^{\circ}C$. The production of resting egg with temperature was showed decrease on the basis on $26^{\circ}C$. The highest number of resting egg per ml and rotifer $10^4$ were 157 eggs and 810 eggs at $26^{\circ}C$, respectively. This result shows that the optimum temperature for mass culture and resting egg production of this freshwater rotifer were $30^{\circ}C$ and $26^{\circ}C$, respectively.

• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.49-55
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• 1996

Water parsley(Oenanthe javanica(Blume) DC) was raised with varying population density(S) in the laboratory aquarium unit to determine the growth equation. The population density was measure after 7 days. The resultant growth curve was well fit to the equation 1/S = A+B (1/S0) with a high correlation coefficient ($R^2$ = 0.999). The maximum specific absorption rate was $9.011 \times 10^{-5}$ kg $NO_x-N/kg$ water parsley$\cdot$day and $1.31 \times 10^{-5}$ kg $PO_4-P/kg$ water parsley$\cdot$day when the average population density was $2.62 kg/m^2$. The relationship between population density and nutrient absorption rate, the absorption rate of $NO_x-N$ was 5.04~5.24 mg/l$\cdot$day when the population density was $7.51~10.0 $mg/m^2\cdot day$ and the absorption rate of $PO_4-P$ was 0.56~0.78 mg/l$\cdot$day when the population density was 5.02~10.0 $kg/m^2\cdot day$. Taking into account the nutrient absorption rate and growth rate, the population density between $7.0 kg/m^2\cdot day$ and $8.0 kg/m^2 \cdot day$ was selected. The removal rate of nutrient was investigated after 7 days culture. Removal rate of $NO_x-N$ was 95.6~99.95% with initial concentration of 35 mg $NO_x-N/l$, and the removal rate of $PO_4-P$ was also high, indicating 80.24~98.9% with initial concentration of 5.95 mg $PO_x-P/l$.

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.39-45
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• 2000

The purpose of this study was conducted to indentified the fixing quality of $CO_2$, the most important greenhouse effect gas, by microalgae Chlorella ellipsoidea in batch test apparatus. The glass flask of $1.4{\ell}$ culture media which was saturated with 99.99% pure $CO_2$ gas was setted water bath of $25^{\circ}C$, 5000Lux, and seeded 100$m\ell$ algae liquid. We checked the change of inorganic carbon concentration and algae population with time in culture media. The result were next: the growth of algae population relied on aquatic IC(inorganic carbon) concentration. And the pH was increased with decrease of IC concentration. The growth of algae population had positive correalation with $CO_2$ concentration, and the coefficient of correlation was 0.982. The specific growth rate($\mu$) of Chlorella ellipsoidea was 1.104/d, the maximum specific growth $rate({\mu}_{max}$) of 9.21/d, and helf velocity constant($K_s$) of $259mg/{\ell}$ by Monod equation.

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.182-188
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• 1999

Production of extracellular polysaccharide by Monilinia fructigena in B-I medium containing cereals was higher than that in glucose medium. Productivities in B-I medium and glucose medium were 0.7g/l nd 0.2-03g/l respectively. The maximum content of polysaccharide occurred at the rising point from the lowest pH of culture. As the apparent viscosity of the polysaccharide solution increased, the flow Index (m) decreased, and the consistency Index (Kc) also increased. The polysaccharide solution was a typical pseudoplastic fluid. The mycelium was separated from the culture solution by $300\mu m$ mesh-filter and the polysaccharide was precipitated by adding 50% of ethanol (v/v). The amount of the polysaccharide removed from the filtrated solution was 0.45 g/l and the amount adhered to the mycelium was 0.25g/l. In experiments for investigating growth enhancement of rotifer (Brachionus plicatilis) by the polysaccharide, the dose of the polysaccharide was 1mg per 10,000 organisms of rotifer. Maximum specific growth rate of rotifer with feed consisting of sea Chlorella sp. and the polysaccharide was 1.095/day in the batch culture for 10 days. A semi-continuous culture was done for 30 days, the biomass of rotifer could be harvested twice. Maximum specific growth rate with sea Chlorella sp. and the polysaccharide was 0.734/day before the first harvest, and 1.685/day before the second harvest. Productivity was 38 $cells/ml\; \cdot\; day$ with sea Chlorella sp. and the polysaccharide.

• KSBB Journal
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• v.10 no.4
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• pp.401-405
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• 1995

An open pond type photobioreactor for mass cultivation of S. platensis was designed and the growth parameters from different cultivation processes were compared. 0.30(1/day) of specific growth rate and 1.69(g/$\ell$) of maximum cell density were obtained from batch cultivation. In fed-batch cultivation, specific growth rate and maximum cell density were estimated as 0.22(1/day) and 1.75(g/$\ell$), respectively. Maximum biomass productively from continuous cultivation was obtained as 0.44 (g/$\ell$/day). It proves that an outdoors-mass cultivation of S. platensis considering optimal environmental condition is economically feasible. In addition, the biomass productivity was studied in two different mixing systems such as agitation and air sparging methods. The biomass productivity by an agitation method was better than that in an air sparging method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.247-255
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• 2005

ice yield and plant growth response to nitrogen (N) fertilizer may vary within a field, probably due to spatially variable soil conditions. An experiment designed for studying the response of rice yield to different rates of N in combination with variable soil conditions was carried out at a field where spatial variation in soil properties, plant growth, and yield across the field was documented from our previous studies for two years. The field with area of 6,600 m2 was divided into six strips running east-west so that variable soil conditions could be included in each strip. Each strip was subjected to different N application level (six levels from 0 to 165kg/ha), and schematically divided into 12 grids $(10m \times10m\;for\;each\;grid)$ for sampling and measurement of plant growth and rice grain yield. Most of plant growth parameters and rice yield showed high variations even at the same N fertilizer level due to the spatially variable soil condition. However, the maximum plant growth and yield response to N fertilizer rate that was analyzed using boundary line analysis followed the Mitcherlich equation (negative exponential function), approaching a maximum value with increasing N fertilizer rate. Assuming the obtainable maximum rice yield is constrained by a limiting soil property, the following model to predict rice grain yield was obtained: $Y=10765{1-0.4704^*EXP(-0.0117^*FN)}^*MIN(I-{clay},\;I_{om},\;I_{cec},\;I_{TN},\; I_{Si})$ where FN is N fertilizer rate (kg/ha), I is index for subscripted soil properties, and MIN is an operator for selecting the minimum value. The observed and predicted yield was well fitted to 1:1 line (Y=X) with determination coefficient of 0.564. As this result was obtained in a very limited condition and did not explain the yield variability so high, this result may not be applied to practical N management. However, this approach has potential for quantifying the grain yield response to N fertilizer rate under variable soil conditions and formulating the site-specific N prescription for the management of spatial yield variability in a field if sufficient data set is acquired for boundary line analysis.

• Microbiology and Biotechnology Letters
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• v.9 no.4
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• pp.225-230
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• 1981

The kinetic study of rifamycin B production in batch culture of Nocardia mediterranei was undertaken in part of our endeavor to optimize the fermentation condition. The growth parameters such as $\mu$$_{m}$ and Ks values for nitrogen source were evaluated by employing Monod equation. From the experiments, $\mu$$_{m}$ and Ks were 0.15hr$^{-1}$ and 8.35g/1, respectively. The growth kinetics in batch culture was found successfully interpreted by logistic law, i.e., the initial specific growth rate and the maximum cell mass concentration were determined as function of pH and both found to have maxima. For the production of rifamycin B, a non-growth associated production kinetics was employed and the specific productivity as a function of pH was found to have two maximum points. The yield coefficient and the specific productivity were calculated as mean values in production phase. Utilizing these experimental data as a function of pH, the optimal condition for the rifamycin B production was discussed with regad to the pH effect on the cell growth and production of the antibiotic. As a result, growth phase at pH 6.5 and production phase at pH 7.0 were found to be recommended.ded.

• ALGAE
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• v.25 no.1
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• pp.17-26
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• 2010

The effects of salinity on various ecophysiological parameters of Ulva pertusa such as growth, nutrient uptake, photosynthetic performance and internal nutrient composition were tested. U. pertusa was collected from an eelgrass bed in a semi-protected embayment on the southwest coast of Korea. Under salinity regimes from 5 to 40 psu, the specific growth rates $(\mu)$ of U. pertusa ranged from 0.019 to $0.032\;d^{-1}$. Maximum growth rate was observed at 20 psu, and minimum at 40 psu. This species showed various uptake rates for nitrate and phosphate. Nutrient uptake was noticeably higher at intermediate salinity levels, and lower at both extremes. Salinity significantly influenced chlorophyll-$\alpha$ content and effective quantum yield. Tissue nitrogen content ranged from 1.5 to 2.9% N (dry weight), whereas tissue phosphorus ranged from 0.1 to 0.14% P (dry weight). The N : P ratio in the tissue of U. pertusa was considerably higher, ranging from 30 to 50. Increased growth at lower salinity suggests that the initial growth rate of U. pertusa is greater during the rainy season (i.e., late spring and early summer) than any other season during the year. The appearance of an Ulva bloom in eelgrass beds may be triggered by salinity more than by other environmental factors such as light and temperature.

• Journal of Environmental Science International
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• v.19 no.5
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• pp.647-653
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• 2010

The objectives of this research are to evaluate and compare the oxygen transfer coefficients($K_{La}$) in both a general bubbles reactor and a micro-nano bubbles reactor for effective operation in sewage treatment plants, and to understand the effect on microbial kinetic parameters of biomass growth for optimal biological treatment in sewage treatment plants when the micro-nano bubbles reactor is applied. Oxygen transfer coefficients($K_{La}$) of tap water and effluent of primary clarifier were determined. The oxygen transfer coefficients of the tap water for the general bubbles reactor and micro-nano bubbles reactor were found to be 0.28 $hr^{-1}$ and 2.50 $hr^{-1}$, respectively. The oxygen transfer coefficients of the effluent of the primary clarifier for the general bubbles reactor and micro-nano bubbles reactor were found be to 0.15 $hr^{-1}$ and 0.91 $hr^{-1}$, respectively. In order to figure out kinetic parameters of biomass growth for the general bubbles reactor and micro-nano bubbles reactor, oxygen uptake rates(OURs) in the saturated effluent of the primary clarifier were measured with the general bubbles reactor and micro-nano bubbles reactor. The OURs of in the saturated effluent of the primary clarifier with the general bubbles reactor and micro-nano bubbles reactor were 0.0294 mg $O_2/L{\cdot}hr$ and 0.0465 mg $O_2/L{\cdot}hr$, respectively. The higher micro-nano bubbles reactor's oxygen transfer coefficient increases the OURs. In addition, the maximum readily biodegradable substrate utilization rates($K_{ms}$) for the general bubbles reactor and micro-nano bubbles reactor were 3.41 mg COD utilized/mg active VSS day and 7.07 mg COD utilized/mg active VSS day, respectively. The maximum specific biomass growth rates for heterotrophic biomass(${\mu}_{max}$) were calculated by both values of yield for heterotrophic biomass($Y_H$) and the maximum readily biodegradable substrate utilization rates($K_{ms}$). The values of ${\mu}_{max}$ for the general bubbles reactor and micro-nano bubbles reactor were 1.62 $day^{-1}$ and 3.36 $day^{-1}$, respectively. The reported results show that the micro-nano bubbles reactor increased air-liquid contact area. This method could remove dissolved organic matters and nutrients efficiently and effectively.

• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.155-159
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• 1978

Phenol utilizing yeast No. 558 isolated from soil sewage sediment was able to use substantial amount of phenol as the sole carbon source, and the biomass productivity by this organism was very excellent. This organism could grow well in 1000 ppm of phenol concentration, the maxim-um specific growth rate obtainable at pH 5.0, 3$0^{\circ}C$ was 0.27/hr., and the biomass yield coefficient Y vs. consumed phenol was 3.2. Maximum production rate of biomass was observed at 35$^{\circ}C$, pH 3.5 to pH 4.5, and the addition of the 0.005~0. 01% yeast extract was the most effective. Addition of HgCl$_2$ and phenyl hydrazine, inhibitors of oxide-reductase, in the phenol containing cultural liquid caused this organism no-growth at the concentration of 10$^{-5}$ M, 10$^{-3}$ M respectively. This organism could utilize not only phenol but catechol, resorcinol and benzidine.