Medium optimization for spore production of Coniothyrium minitans using statistically-based experimental designs

Statistically-based experimental designs were used to optimize a chemically defined solid medium for the spore production of Coniothyrium minitans. In the first optimization step the influence of starch, urea, phosphate, magn esium, calcium, thiamin and trace elements on spore production was evaluate d using a fractional factorial design. Starch and trace elements influenced spore production positively while urea affected spore production negativel y. The other components had no significant influence on spore production. I n the second and third steps the concentrations of starch, urea and trace e lements were further optimized using central composite designs and response surface analysis. This optimization strategy allowed the spore production to be increased by a factor 7 from 4 x 10(9) to almost 3 x 10(10) spores pe r Petri dish of 9 cm diameter. (C) 1999 John Wiley & Sons, Inc.