An article in Applied Biochemistry and Biotechnology (A Statistical Approach for Optimization of Polyhydroxybutyrate Production by Bacillus sphaericus NCIM 5149 under Submerged Fermentation Using Central

An article in Applied Biochemistry and Biotechnology (€œA Statistical Approach for Optimization of Polyhydroxybutyrate Production by Bacillus sphaericus NCIM 5149 under Submerged Fermentation Using Central Composite Design€ (2010, Vol. 162(4), pp. 996€“1007)] described an experiment to optimize the production of polyhydroxybutyrate (PHB). Inoculum age, pH, and substrate were selected as factors, and a central composite design was conducted. Data follow.

(a) Plot the points at which the experimental runs were made. What type of design is used?

(b) Fit a second-order response surface model to the data.

(c) Does a residual analysis indicate any problems?

(d) Construct a contour plot and response surface for PHB amount in terms of two factors.

(e) Can you recommend values for inoculum age, pH and substrate to maximize production?

PHB PHB Inoculum age Substrate (g/L) 1 1 2.5 (g/L) Run (h) 12 24 pH 4 1 0.84 0.55 1.96 8. 6. 18 2.