FIG. 5.

Effect of IPTG concentrations on growth and alginate production in FRD1050 and FRD1300. Overnight cultures were used to inoculate MAP medium and incubated with aeration at 37°C to an OD₆₀₀ of 0.20. Twenty-five-milliliter volumes of log-phase cultures were incubated with 4.0 mM IPTG (A) or 0.4 mM IPTG (B) to induce alginate production. Samples were taken periodically for measurements of growth as OD₆₀₀ (closed symbols) and alginate accumulation in culture supernatants (open symbols). FRD1050 algL⁺, squares; FRD1300 ΔalgL, circles. A repeat of this experiment produced similar results.