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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Optimization of Growth and Production of Docosahexaenoic Acid by Schizochytrium limacinum BR2.1.2 Using Plackett-Burman Design and Central Composite Design with Response Sur ผู้เขียน: Lalida Kawsakul,  ดร.วิเชียร ยงมานิตชัย, อาจารย์ , ดร.เดือนรัตน์ ชลอุดมกุล, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractCulture conditions to maximize growth and the production of docosahexaenoic acid (DHA) by Schizochytrium limacinum BR2.1.2 were optimized using two statistical experimental designs. Three critical factors—temperature, glycerol concentration and peptone concentration—for biomass and DHA production were pre-evaluated by the Plackett-Burman design using low and high levels of the three variables. Low temperature, high glycerol and high peptone concentrations signifi cantly infl uenced both determined parameters. A central composite design and response surface plots were used to optimize the proved signifi cant factors and to generate maximum biomass and DHA production. A second order polynomial equation was generated for dried cell weight (DCW) as YDCW = -83.17811 + 7.77533X1 + 22.49818X2 - 32.53142X3 - 0.12375X1X2 + 0.73850X1X3 + 5.41750X2X3 - 0.20343X1 2 - 1.95541X2 2 - 9.21053X3 2 and that for DHA as YDHA = -21.51223 + 1.32761X1 + 5.27758X2 - 4.69083X3 - 0.01150X1X2 + 0.15400X1X3 + 0.65500X2X3 - 0.036655X1 2 - 0.45401X2 2 - 1.51840X3 2. Five levels of each factor at -1.68, -1, 0, +1 and +1.68 were tested in 17 experiments to validate both models. The P-values were less than 0.05 suggesting that the models were acceptable at this level of signifi cance. The optimal values for temperature, glycerol and peptone concentrations were 18.9 ?C, 6.1% and 0.7%, respectively, and yielded 48.31 g?L-1 of DCW and 5.34 g?L-1 of DHA. Verifi cation of the optimal conditions showed that deviations of DCW and DHA from the experimental data and predicted values were 3–5% and less than 2%, respectively, suggesting that the experimental designs used in this work were effective for growth and DHA production. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Optimization of Lipid Accumulation by Starchless Mutant Chlorella sorokiniana for Biodiesel Production) ผู้เขียน:Watchara Jantasee, ดร.วิเชียร ยงมานิตชัย, อาจารย์, ดร.เดือนรัตน์ ชลอุดมกุล, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractImprovement of oil accumulation in Chlorella sorokiniana was conducted by ultraviolet mutagenesis. In total, 63 starchless mutants from over 40,000 colonies were screened using an iodine fumigation technique. Eight starchless mutants had relatively high levels of oil accumulation compared to wild type strains. The lipid content of starchless C. sorokiniana DMKU5202-31 increased from 15% to 21.16%. Therefore, this strain was selected for further optimization using a statistical experimental design. Seven factors were screened using a Plackett-Burman design and further optimized using a central composite design (CCD). The Plackett-Burman design presented three significant factors—KNO3, pH and light intensity—that affected biomass and lipid accumulation significantly. CCD was used to optimize the significant factors and indicated that the optimal values for KNO3, pH and light intensity were 0.9 g.L-1, 6.2 and 4,000 lux, respectively. The response surface plots revealed that the maxima for biomass, lipid production and lipid content were 2.58 g.L-1, 1.40 g.L-1 and 54.49%, respectively. Thus, it could be concluded that ultraviolet mutation and the statistical experimental design can be used to improve oil accumulation in C. sorokiniana. After mutation and optimization, strain DMKU5202 had a lipid content increase from 15% to 54.49%. Therefore, these techniques were very efficient for the development of an upstream process for biodiesel production. |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Optimization of Growth and Hydrocarbon Production from a Green Microalga Botryococcus braunii by Plackett-Burman Design and Response Surface Methodology) ผู้เขียน:Siriphan Channamtum, ดร.วิเชียร ยงมานิตชัย, อาจารย์, ดร.เดือนรัตน์ ชลอุดมกุล, ผู้ช่วยศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractStatistical experimental designs were used to optimize the culture conditions on growth and hydrocarbon production from a green microalga Botryococcus braunii J4-1. In the optimization process, seven independent variables—NaNO3, KH2PO4, Fe-citrate, pH, NaHCO3, CO2 and light intensity—were screened to verify the three most critical variables by the Plackett-Burman design. Fe-citrate, pH and CO2 were then selected for further optimization by central composite design coupled with response surface methodology. Seventeen experimental tests were run under five levels of the significant variables. The influence of these variables on the responses of biomass, chlorophyll and hydrocarbon was evaluated using a second-order polynomial multiple regression model. Analysis of variance showed a high correlation coefficient of determination value of more than 0.90 and the P-values were less than 0.05. These values indicated that the model had a good fit and was acceptable at this level of significance. The optimum values of the variables were Fe-citrate 1.5 mg.L-1, pH 6.8 and CO2 2.5% (volume per volume) gave maximum yield of biomass at 5.74 g.L-1, 13.51 mg.L-1 of chlorophyll and hydrocarbon 1.44 g.L-1. Validation of the experimental values using the optimal conditions showed that the experimental values were quite close to the predicted values. Furthermore, the corresponding results of the deviations for the production of biomass, chlorophyll and hydrocarbon were 10.17, 11.19 and 1.41%, respectively, suggesting that the experimental designs used in this work were effective for the optimization of the process parameters on biomass, chlorophyll and hydrocarbon production. |
ที่มา:Songklanakarin Journal of Science and Technologyหัวเรื่อง:การพัฒนาแบบจำลองเพื่อใช้ทำนายการเจริญของ Salmonella spp. ในข้าวผัดปู |
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