Strain development by evolutionary engineering in two stages. Panel A: Strains representing population A are sorted according to their μ. Upper bounds of classes are shown as dashed lines. Insert shows the corresponding histogram. Increase of μ along the classes is indicated by an arrow. Panel B: Growth characteristics of IBB10A02 (full circles) and IBB10B05 (empty circles) under uncontrolled and IBB10A02 under controlled (full triangles) pH conditions. Panel C. Evolution of population B from IBB10A02 by sequential batch selection. Panel D: μ s (black bars) and Y
xylitols (grey bars) are indicated. Error bars indicate standard deviations obtained from two individual cultivations (Panels: A, C, D) or from triplicate measurements of OD600 (Panel B).