Statistical measurement of biotin, thiamine, and zinc concentrations required for maximal growth of Arthrobotrys conoides.

An experiment of central composite design was performed to determine simultaneously the most suitable concentration of each of three nutrients essential for proliferation of the nematode-trapping fungus, Arthrobotrys conoides, and to detect any significant interaction that occurred when they were supplied at different levels. Regression analyses of the results obtained revealed that for maximal growth of A. conoides in a glucose-inorganic salts medium, biotin, thiamine, and zinc were required at concentrations of 5, 100, and 400 mug/liter, respectively. No interaction of significance was detected. The analytical procedures are presented in detail, and the benefits that accrue from a statistical approach are discussed.