FIG. 1.

Mean cell dry weight yields of A. niger N402 in ACM (pH 4.0) (•, control) and with 1.0 mM (○) or 3.0 mM (▾) sorbic acid added to the medium. Shake flasks of 250-ml capacity, containing 100 ml of medium, were inoculated with 10⁷ spores and incubated at 28°C with orbital shaking at 160 rpm. Vertical bars show standard errors of the mean (SEM) (n = 3) calculated from independent cultures. Results from ethanol controls were identical to those from water controls and are therefore not presented.