An article in Bioresource Technology [Medium Optimization for Phenazine-1-carboxylic Acid Production by a gacA qscR Double Mutant of Pseudomonas sp. M18 Using Response Surface Methodology

An article in Bioresource Technology [€œMedium Optimization for Phenazine-1-carboxylic Acid Production by a gacA qscR Double Mutant of Pseudomonas sp. M18 Using Response Surface Methodology€ (Vol. 101(11), 2010, pp. 4089-4095)] described an experiment to optimize culture medium factors to enhance phenazine-1-carboxylic acid (PCA) production. A 2^5ˆ’1 fractional factorial design was conducted with factors soybean meal, glucose, corn steep liquor, ethanol, and MgSO₄. Rows below the horizontal line in the table (coded with zeros) correspond to center points.

(a) What is the generator of this design?

(b) What is the resolution of this design?

(c) Analyze factor effects and comment on important ones.

(d) Develop a regression model to predict production in terms of the actual factor levels.

(e) Does a residual analysis indicate any problems?

X, X3 X4 X5 Production (g/L) Run , 1575.5 1 2201.4 1813.9 4 2164.1 1739.6 2483.2 2159.1 2257.7 1386.3 10 1967.8 11 1306.0 12 2486.9 2374.9 13 14 2932.7 15 2458.9 16 3204.9 17 2630.4 18 2571.6 19 2734.5 20 2480.4 21 2662.5 + II + I + + II + +| + | +O o o O- + O 0 I + I + | +| +I + I +I +| +O O