Figure 4. Effect of Cultural Conditions on the Growth and Production of Antimicrobial Metabolites.

A, effect of incubation time in days, B, effect of agitation speed (rpm) of the shaking incubator during the incubation period, C, effect of the pH of the production medium, and D, effect of incubation temperature (°C) at four different levels. All experiments were performed in triplicate and the values are represented as the mean of three observations. The error bars indicate the standard deviation among treatments. The bars tagged with same alphabetic letter do not differ significantly at a 95% confidence level, while letters followed by the asterisk symbol (*) denote significantly higher values (P < 0.05).