• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.490-496
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• 2002

The production of E. coli WC7 phytase from a recombinant E. coli strain was optimized using a statistical experimental design approach. Two-level complete factorial designs with seven variables were used for the media optimization. In the first optimization step, the influence of disodium succinate, yeast extract, $K_2HPO_4,\;NH_4H_2PO_4,\;MgSO_4$, NaCl, and trace elements on phytase production was evaluated. As a result, disodium succinate, yeast extract, $NH_4H_2PO_4$, NaCl, and the trace elements were found to have a positive influence on the phytase production, while $K_2HPO_4\;and\;MgSO_4$ had a negative influence. In the second step, the concentrations of disodium succinate and yeast extract were further optimized using central composite designs. The maximum phytase activity obtained was 234 U/ml using 15.9 g/1 disodium succinate, 20 g/1 yeast extract, 5 g/1 K_2HPO_4,\;10 g/1 NH_4H_2PO_4,\;1.5 g/1 MgSO_4$, 4 g/1 NaCl, and 1.5 m1/1 trace elements, which was about a 14-fold increase in comparison with that obtained using the basal medium.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.

• International Journal of Fluid Machinery and Systems
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• 제10권3호
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• pp.264-273
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• 2017

In order to be able to predict the maximum Annual Energy Production (AEP) for tidal power plants, an AEP optimization tool based on Evolutionary Algorithms was developed by ANDRITZ HYDRO. This tool can simulate all operating modes of the units (bi-directional turbine, pump and sluicing mode) and provide the optimal plant operation that maximizes the AEP to the control system. For the Swansea Bay Tidal Power Plant, the AEP optimization evaluated all different hydraulic and operating concepts and defined the optimal concept that led to a significant AEP increase. A comparison between the optimal plant operation provided by the AEP optimization and the full load operating strategy is presented in the paper, highlighting the advantage of the method in providing the maximum AEP.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.1996-2004
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• 2007

In this study, the optimization of culture medium using a Sterigmatomyces elviae mutant was investigated using statistical analysis to increase the cell mass and lactosucrose ($^4G-{\beta}$-D-galactosylsucrose) production. In basal medium, the cell mass and lactosucrose production were 4.12 g/l and 140.91 g/l, respectively. However, because of the low cell mass and lactosucrose production, optimization of culture medium was carried out to increase the cell mass and lactosucrose production. Culture media were optimized by the S. elviae mutant using analysis of variance (ANOVA) and response surface methodology (RSM). Central composite designs using RSM were utilized in this investigation. Quadratic models were obtained for cell mass and lactosucrose production. In the case of cell mass, optimal components of the medium were as follows: sucrose 1.13%, yeast extract 0.99%, bactopeptone 2.96%, and ammonium sulfate 0.40%. The predicted maximum value of cell mass was about 5.20 g/l and its experimental value was 5.08 g/l. In the case of lactosucrose production, optimal components of the medium were as follows: sucrose 0.96%, yeast extract 1.2%, bactopeptone 3.0%, and ammonium sulfate 0.48%. Then, the predicted maximum value of lactosucrose production was about 194.12 g/l and the corresponding experimental value was about 183.78 g/l. Therefore, by culturing using predicted conditions, the real cell mass and lactosucrose production increased to 23.3% and 30.42%, respectively.

• Archives of Pharmacal Research
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• 제19권3호
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• pp.173-177
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• 1996

The Pneumococcus, Streptococcus pneumoniae, has an ample polysaccharide (PS) capsule that is highly antigenic and is the main virulence factor of the organism. The capsular PS is the source of PS vaccine. This investigation was undertaken to optimize the culture conditions for the production of capsular PS by type 4 pneumococcus. Among several culture media, brain heart infusion (BHI) and Casitone based medium were found to support luxuriant growth of pneumococcus type 4 at the same level. Therefore in this study, the Casitone based medium was used to study optimization of the culture condition because of BHI broth's high cost and complex nature. The phase of growth which accomodated maximum PS production was exponential phase. Concentrations of glucose greater than 0.8% did not enhance growth or PS production. Substitution of nitrogen sources with other resources or supplementation of various concentrations of metal ion (with the exception of calcium, copper, and magnesium ions) had adverse effects on growth and PS production. On the other hand, low level aeration and supplementation of 3 mg/l concentration of asparagine, phenylalanine, or threonine were beneficial for increased PS production. The synergistic effect of all the favorable conditions observed in pneumococcal growth assays provided a two-fold cumulative increase in capsular PS production.

• 한국기계가공학회지
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• 제6권1호
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• pp.71-77
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• 2007

In case of the welding process, a conventional production method of gate valve, it has a merit of light weight, but also a demerit of high production cost and an impossibility in mass production due to work by hand. However, in case of the forging process, it has economic merits and can take a mass production process, too. The main focus of this paper is the optimization of preform in the forging process. This paper proposed an optimal design to improve the mechanical efficiency of gate valve made by forging method instead of welding. the optional design is conducted as application of real response model to Kriging model using computer simulation. Also, from verification of the response model with optimized results we were confirmed that the applications of Kriging method to structural optimum design using finite element analysis and equation are useful and reliable.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.113-116
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• 1995

In this study, we formulate production costing problem with environmental and operational constraints into an optimization problem of LP form. In the process of formulation, auxiliary constraints on which reflect unit loading order are constructed to reduce the size of optimization problem by economic operation rules. As a solution of the optimization problem in LP form, we use Karmarkar's method which performs much faster than simplex method in solving large scale LP problem. The proposed production costing algorithm is applied to IEEE Reliability Test System, and performs production simulation under environmental and operational constraints. Test and computer results are given to show the accuracy and usefulness of the proposed algorithm in the field of power system planning.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1362-1366
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• 2003

Workload programming is allocating suitable workloads of production process according to the needs of products, which would minimize the total cost of both work and stock under some constraint conditions. In this paper, a production process flow chart of discrete manufacturing is presented by a Petri net, and the optimization model of workload-stock is established. An approach of the optimal workloads is provided by means of the integer matrix theory. An example is given to verify this method.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.175-178
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• 2003

In recent years, several researchers have presented the extensive research reports on network optimization problems. In our real life applications, many important network problems are typically formulated as a Maximum flow model (MXF) or a Minimum Cost flow model (MCF). In this paper, we propose a Genetic Algorithm (GA) approach used a priority-based chromosome for solving the bicriteria network optimization problem including MXF and MCF models(MXF/MCF).

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2008년도 추계 공동 국제학술대회
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• pp.463-467
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• 2008

Heuristic optimization using hybrid algorithms have provided a robust and efficient approach for solving many optimization problems. In this paper, a new hybrid algorithm using adaptive genetic algorithm (aGA) and particle swarm optimization (PSO) is proposed. The proposed hybrid algorithm is applied to solve numerical optimization functions. The results are compared with those of GA and other conventional PSOs. Finally, the proposed hybrid algorithm outperforms others.