The article Efficient Pyruvate Production by a Multi-Vitamin Auxotroph of Torulopsis glabrata: Key Role and Optimization of Vitamin Levels (Y. Li, J. Chen, et al.

The article €œEfficient Pyruvate Production by a Multi-Vitamin Auxotroph of Torulopsis glabrata: Key Role and Optimization of Vitamin Levels€ (Y. Li, J. Chen, et al. Applied Microbiology and Biotechnology, 2001:680€“685) investigates the effects of the levels of several vitamins in a cell culture on the yield (in g/L) of pyruvate, a useful organic acid. The data in the following table are presented as two replicates of a 2³design. The factors are A: nicotinic acid, B: thiamine, and C: biotin. (Two statistically insignificant factors have been dropped. In the article, each factor was tested at four levels; we have collapsed these to two.)

a. Compute estimates of the main effects and interactions, and the sum of squares and P-value for each.

b. Is the additive model appropriate?

c. What conclusions about the factors can be drawn from these results?

Yields Mean Yield -1 -1 -1 0.55, 0.49 0.60, 0.42 0.37, 0.28 0.30, 0.28 0.54, 0.54 0.54, 0.47 0.44, 0.33 0.36, 0.20 0.520 -1 0.510 0.325 -1 0.290 0.540 0.505 0.385 0.280