• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.4
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• pp.67-72
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• 2004

This paper proposes a method improving the convergence speed of optimal solution for parallel genetic algorithm in the network based client-server model. Unlike the existing methods of obtaining global elite only by evaluating local elites in server, the proposed method obtains it by evaluating local elites and improving its fitness by applying genetic algorithm during idle time of the server. By using the improved chromosome in server for the client's genetic algorithm processing, the convergence speed of the optimal solution is increased. The improvement of fitness at the server during the interval of chromosome migration is (equation omitted)(F$_{max}$(g)-F$_{max}$(g-1)), whole F$_{max}$(g) is a max fitness of the g-th generation and G is the number of improved generation by the server. As the number of clients increases and G decreases, the improvement of fitness goes down. However the improvement of fitness is better than existing methods..

• KSBB Journal
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• v.8 no.5
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• pp.452-456
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• 1993

This study was carried out to optimize the fermentation conditions for direct alcohol fermentation of xylose by Pichia stipitis CBS 5776. The best cell growth and the ethanol production were obtained under 0.05 VVM aeration and 300rpm agitation at $30^{\circ}C$ using 100 g/l xylose medium of the initial pH 5.0. In the above condition, the maximum specific growth rate and maximum cell concentration were 0.14hr-1 and $1.3 \times109$ cells/ml, respectively. Pichia stipitis CBS 5776 also produced 40.2g/l ethanol utilizing about 96% of 100g/l xylose after 72hr fermentation. At this point, the overall volumetric ethanol productivity was 0.56g/1-hr and the ethanol yield was 0.42 g-ethanol/g-xylose consumed, which corresponds to 82% of the theoretical yield.

• KSBB Journal
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• v.7 no.4
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• pp.258-264
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• 1992

The rheological characteristics of the ethanol fermentation broth were pseudoplastic when the yeast concentration was above 150g/L. From the viewpoint of rheological properties, the cell concentration below 150g/L was recommended for ethanol fermentation. Since the cell floc was formed at the cell concentration of 100 g/L, yeast cells were not much plugged in the pores of the membrane. The cell concentration above 100g/L was desirable when considering the permeability of the membrane. Since ethanol productivity was the highest when the cell concentration was 130 g/L in cell recycled ethanol fermentation. The optimal dilution rate was determined at 1.3 h-1 at constant cell mass of 130g/L. At this dilution rate, the ethanol productivity and glucose conversion ratio ware 80 g/L$\cdot$h and 0.94, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.359-368
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• 2008

Black soybean has been widely utilized as foods and oriental medicinal materials. The pigmentation in the seed coat of black soybean is due to accumulate anthocyanins in the epidermis palisade layer. The anthocyanins of black soybean seed coat are considered as a parameter of quality evaluation of black soybean. Therefore, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of anthocyanins in black soybean seed coats extracts. The efficient HPLC analytical condition of D3G, C3G, and Pt3G contained extracts of black soybean seed coats was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 5% aqueous formic acid, and mobile phase B, comprising 5% formic acid - acetonitrile, and delivered at a flow rate of 0.7 mL/min as follows: $0{\sim}35\;min$, $90%\;A{\sim}60%\;A$; 36 min, 90% A; 46 min, 90% A. The UV-VIS. detection wavelength was set at 520 nm. The limit of detection (LOD) for D3G, C3G, and Pt3G were under 10 ng/mL.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.411-416
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• 1993

This study was conducted to determine optimum levels of ingredients including yeast autolyzate, first for the beef flavored soup base and then for the soy paste stew mix as a final product. Response surface methodology was used for the optimization. Beef flavored soup base with optimum sensory characteristics could be prepared with 8g/l yeast autolyzate, 0.8g/l nucleotide seasoning, and 0.09g/l succinic acid. And soy paste stew mix could be produced with 8g/l beef flavored soup base, 28g/l soy paste powder, and 16g/l corn starch. Soy paste stew prepared with optimum levels of ingredients were comparable in acceptability to that with commercial product containing beef extracts. It was suggested that sufficient beef flavor could be obtained with yeast autolyzate in such products as soy paste stew mix.

• KSBB Journal
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• v.14 no.5
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• pp.628-632
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• 1999

Optimization of the medium and fermentation conditions for erythritol production has been studied. We have found that the optimal carbon source was glucose at the concentration of 400 g/L. The optimal temperature was 3$0^{\circ}C$ with excessive aeration. Improved erythritol productivity was achieved by reducing the yeast extract from 5 g/L to 3g/L while adding 2.7 g/L urea, 1.79g/L $K_2HPO_4, and 0.18g/L MgSO$_4$. 7$H_2O. The erythritol productivity increased from 0.747 g/L/h to 1.071 g/L/h and the yield increased from 31.4% to 45.2%. The byproduct glycerol was reduced from 96.6g/L to 45.7g/L as well. We have performed 5L fermentation with and without the pH control. The erythritol productivity with the pH control was about 30% lower than that without pH control. Excessive foaming of 5L fermentation has been observed during fermentation.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.286-297
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• 1994

The optimum nutritional and cultural conditions of polygalacturonase by Ganoderma lucidum in liquid culture were studied. The optimal temperature, pH, and the duration of culture for production of the enzyme was $30^{\circ}C$, 5.5 and 14 days, respectively. The maximal production of the enzyme was obtained in a synthetic medium containing 10 g of pectin, 10 g of soluble starch, 1 g of yeast extract, 2 g of peptone, 1 g of phenylalanine, 2 g of $KH_2PO_4$, 0.2 g of $MgSO_4{\cdot}7H_2O$, 0.05 g of $CaCI_2$ and 100 g of $thiamin{\cdot}HCI$ in 1000 ml of distilled water.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.490-497
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• 2011

In this study, we determined optimal conditions for simultaneous saccharification and fermentation (SSF) using corncob biomass pretreated with oxalic acid. The effect of SSF temperature ($25.8{\sim}34.2^{\circ}C$) and agitation speed (80~220 rpm) were significant at a 99% confidence level in its effect on ethanol production. The highest ethanol production was expected when SSF was performed at $30^{\circ}C$, 170 rpm (22.5 g/L). The ethanol production was improved by mixture of yeast extract (1.25 g/L) and urea (1.25 g/L) as nitrogen source. However, addition of trace metal components and vitamin for SSF was not affected in the ethanol production. Optimal concentration of $KH_2PO_4$, $MgSO_4{\cdot}7H_2O$ for SSF was 1 g/L, 0.25 g/L respectively.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.668-676
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• 1992

For the purpose of optimizing poly-l3-hydroxybutyrate (PHB) production from Alcaligenes eutrophus, two-stage fed-batch culture was adopted. In this system, specifk growth rate was maximized during the first stage whereas specific production rate was maximized during the second stage. The optimal concentrations of glucose and ammonium chloride were 16.6 and 0.54 g/I in the growth stage and 20.0 and 0.07 g/l in the production stage, respectively. Proportional feedback control considering time lag was suggested for PHB production process and a simulator was developed for real-time control purpose.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.237-240
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• 2000

Organic acids which were produced from biomass wastes streams by cell-recycle fermentation using Propionibacterium acidipropionici ATCC 4965 were extracted by Membrane Contactor using TOA/MIBK system. Maximum productivity was 3.32g organic acid/L/hr at the dilution rate of 0.2/hr in the results of continuous fermentation. The diluted organic acids in the fermenter were selectively separated by Membrane Contactor extraction using 30%(w/w) trioctylamine(TOA) dissolved in methylisobutylketone(MIBK). The flow rate of aqueous phase is 200ml/min and that of extraction phase is 100ml/min. The degree of Acetic acid and Propionic acid extraction from fermentation broth was reached 56.25%, 72.41% respectively.