Effect of inoculum of various sizes and ages on the production of cephalosporin by Acremonium chrysogenum in shake flasks. All the values are means of three parallel replicates. Y- error bars indicate the standard error from mean. Fermentation conditions: Incubation period = 144 h; incubation temperature = 30 °C; pH = 6.5. C, amount of cephalosporin; DMM, dry mycelial mass.