• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.1-8
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• 2007

A series of batch and column experiments were conducted for the development of biobarrier technology which can be applied to containment and reduction of contaminants in soil and ground waters. The growth kinetic constants of Pseudomonas fluorescens on glucose or molasses were determined using batch experiments. The maximum specific growth rate (Vmax) of P. fluorescens at $23^{\circ}C$ on glucose or molasses were $0.246\;hr^{-1}$ and $0.073\;hr^{-1}$, respectively. However, molasses was selected as carbon source due largely to the absence of lag phase of P. fluorescens growth on molasses and economic reason. In constant head column experiments, the hydraulic conductivity of the column soil reduced by $6.8{\times}10^{-3}$ times from $4.1{\times}10^{-2}cm/sec$ to $2.8{\times}10^{-4}cm/sec$ after the inoculation of P. fluorescens and administration of carbon source and nutrients. The biomass concentration was observed highest in the column inlet. Measurements of carbon source and electron accepter (dissolved oxygen) concentration showed that the growth of P. fluorescence, which is the main reason for hydraulic conductivity reduction, was limited not by the concentration of carbon source but by the concentration of electron acceptor.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.215-221
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• 2005

It was characterized the hexane biodegradation and mineralization using a hexane-degrading consortium, and analyzed its bacterial community structure by 16S rDNA PCR-DGGE (denaturing gradient gel electrophoresis). The specific growth rate (${\mu}_{max}$) of the hexane-degrading consortium was 0.2 $h^{-1}$ in mineral salt medium supplemented with hexane as a sole carbon source. The maximum degradation rate ($V_{max}$) and saturation constant ($K_{s}$) of hexane of the consortium are 460 ${\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ and 25.87 mM, respectively. In addition, this consortium could mineralize $49.1{\%}$ of $^{14}C$-hexane to $^{14}CO_2$, and $43.6{\%}$ of $^{14}C$-hexane) was used for the growth of biomass. The clones isolated from the DGGE bands were closely related to the bacteria which were capable of degrading pollutants such as oil, biphenyl, PCE, and waste gases. The hexane-degrading consortium obtained in this study can be applied for the biological treatment of hexane.

• Ocean and Polar Research
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• v.35 no.4
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• pp.407-414
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• 2013

One of the most important challenges facing the Spirulina mass cultivation industry is to find a way to reduce the high production costs involved in production. Although the most commercial medium (Zarrouk's medium) for Spirulina cultivation is too expensive to use, it contains higher amount of $NaHCO_3$ (16.80 g $L^{-1}$), trace metals and vitamin solutions. The purpose of this study was to increase the efficiency of Spirulina platensis biomass production by developing a low-cost culture medium at an isolated tropical island such as Chuuk State, Federated States of Micronesia (FSM). This study set out to formulate a lowcost medium for the culture of S. platensis, by substituting nutrients of Zarrouk's medium using fertilizer- grade urea and soil extract with a different concentration of carbon source under natural weather condition. In order to select a low-cost culture medium of S. platensis, 10 culture media were prepared with different concentrations of nitrogen (urea and $NaNO_3$) and $NaHCO_3$. The highest maximum specific growth rate (${\mu}max$) and mass production were 0.50 $day^{-1}$ and 1.05 g $L^{-1}$ in modified medium ($NaHCO_3$ 7.50 g $L^{-1}$, urea 2.00 g $L^{-1}$ without $NaNO_3$) among all the synthesized media. Protein (56.14%) and carbohydrate (16.21%) concentrations of the lyophilized standard samples were estimated with highest concentration of glutamic acid (14.93%). This study revealed that the use of a low concentration of urea and $NaHCO_3$ with soil extract was an affordable medium for natural mass cultivation in the FSM.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.226-236
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• 1999

Growth, reproduction, mortality, and production of Laminaria japonica were experimentally studied at a cultivation ground on the coast of llkwang, where the largest amount of cultivated Laminaria has been produced in Korea. For this experiment, young sporophytes (0.33 cm in mean length) grown in the laboratory were transplanted at the depth of 3 m and field surveys on them were conducted twice a month from December, 1995 to August, 1996. Plants exhibited an annual life span; they were completely dead by August. Frond width, thickness, and wet weight showed similar pattern of seasonal growth and reached their maxima in July, but frond length showed no more increment after May. Maximum mean frond length and weight were 199.8 cm and 333.0 g wet wt., respectively. Overall meristematic growth in length and weight were 384.0 cm and 393.6 g wet wt., respectively. Absolute growth rates (AGR) which were calculated from the length of tissue developed from meristem varied seasonally; AGR of length and weight reached maxima in March (3.6 $cm{\cdot}d^{-1}$) and May (3.8 g wet $wt{\cdot}d^{-1}$), respectively. Absolute attrition rates gradually increased from February to July. Seasonal differences in growth and attrition rates appeared to be related to seawater temperature and nitrogen concentration in seawater. Reproductive sporophytes bearing sprorangium sorus began to occur from April, and the ratio of sorus area to blade area reached its maximum in July (0.034). Survival rate was exponentially decreased; more than 90% of plants decayed within 56 days after outplanting. After February, mortality was size-specific; mortality of smaller plants less than 30 cm in length were relatively higher. Maximum biomass occured in July (285.6 kg wet $wt{\cdot}m^{-2}$) and annual production was 758.7 kg wet $wt{\cdot}m^{-2}$.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.121-132
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• 2000

This study is to investigate the performance of a new BNR process using predenitrification scheme focusing on nitrogen removal and the possibility of adapting a computer simulation scheme in BNR process development. By using a pre-denitrification basin, higher $COD/NO_3-N$ ratio could be sustained in this BNR process. The results of the investigation showed a SDNR value of 9.04mg/gMv/hr. In the anoxic tank, the average value of SPRR of 6.25mgP/gMv/hr was observed to be very sensitive to SCOD load of influents. By calibrating internal parameters (stoichiometric and kinetic parameters) of the simulation model, the results of simulation for various BNR processes gave good agreement with observed data. The major adjustment was given with three parameters, maximum specific growth rate of heterotrophic biomass, short chain fatty acid (SCFA) limit, and phosphorous release rate. With the series of simulations on varying operational conditions, the simulation by computer program can be a useful tool for process selection, and design and operation of municipal wastewater treatment plant.

• Applied Biological Chemistry
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• v.27
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• pp.29-46
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• 1984

To utilize several species of hard wood as raw materials of feed products, fermentation characteristics of cellulosic substrates to single cell protein was investigated, and results were summarized as follows. Among the microorganisms investigated, Tricoderma viride was selected as one of the most cellulolytic. Mixed culture of fungi did not show a synergistic effect on cellulose degradation. When the fungi were cultured at $28^{\circ}C$ for 7 days in a medium containing wheat bran 25 g, cellulose 0.25 g, proteose peptone 0.025 g and tween 800.025 g, cellulotic activities on carboxy methyl cellulose and filter paper reached maximum at 12 hr. The alkali treatment resulted in increased degradation of substrate from 13 to 18% when treated with enzymes for 12h, and reducing sugar formation increased with decreased size of substrates. Glucose was a very good feedback inhibitor of the enzyme from T.viride than that of xylose. When the substrate was rehydrolyzed, hydrolysis rate was 31% to reducing sugars within 12 hr. Quantative anlysis with HPLC showed the ratio of glucose to xylose in sugar syrups as 1.77 to 1. For the purpose of producing cellulosic-single cell protein from the sawdust of mulberry tree, 15 strains of xylose-assimilating yeast were isolated from 42 samples of rotten woods and compost soils and examined for their ability to utilize xylose. Then three strains were selected by their strong xylose-assimilating activities. The cultivative condition, the growth characteristics, and protein and nucleic acid productivities of three strains were investigated. The results obtained were, 1. Wood hydrolysate of mulberry tree was assimilated by 5 strains of CHS-2, CHS-3, ST-40, CHS-12 and CHS-13. 2. The optimum initial pH and temperature for the growth of strain CHS-13 were 4.4 and $30^{\circ}C$. 3. The specific growth rate of strain CHS-13 was $0.23h^{-1}$ and generation time was 3.01 hrs at the optimum condition. 4. CHS-13 strain assimilated 81 % of sugar in wood hydrolysate. 5. CHS-13 strain was identified as Candida guilliermondii var. guilliermondii 6. When the CHS-13 strain was cultured in the wood hydrolysate containing yeast extract, L-protein content was increased with yeast extract concentration. 7. The L-protein and nucleic acid yields from wood hydrolysate were 0.73 mg/ml and $4.92{\times}10^{-2}\;mg/ml$ respectively. 8. An optimal nucleic acid content of CHS-13 strain was observed in the medium containing 0.2% of yeast extract.