FIG 4.

Growth and volatile compound profiles of strains KGMA0119 (wild type), KGMA5511 (ΔpyrE ΔilvC::pyrE), and KGMA7203 [ΔpyrE KelrpΔ(397-511)::pyrE]. The three strains were cultured in YPD broth supplemented with 1.0% sodium l-lactate (and 12 mM BCAAs for KGMA5511). The amounts of acetoin, acetic acid, and ethanol in cultures were measured by GC. Shown are profiles of growth (OD₆₆₀) (A), acetoin (% [wt/vol]) (B), acetic acid (% [wt/vol]) (C), and ethanol (% [wt/vol]) (D). White triangles, KGMA0119; dark gray squares, KGMA5511; black circles, KGMA7203. Experiments were conducted in triplicate, and error bars indicate standard deviations.