Fig. 3

Evolution of strains expressing hexose–proton for growth under anaerobic conditions. A Mutations that arose in transporters during evolution of hexose–proton symporter-expressing strains under anaerobic conditions. B Structural models of KlFrt1 (top left) and KmHgt1 (top right) and both structures superimposed (bottom), highlighting the locations of amino acid residues that mutated during evolution in magenta and orange. C Growth of reverse engineered strains IME666 (KlFRT1^T767C) in SM with 20 g L⁻¹ fructose and IME752 (KmHGT1^T1058C and SeFSY1) in SM with 20 g L⁻¹ sucrose or in SM with 20 g L⁻¹ glucose in anaerobic shake flasks. Data represent average and mean deviation of two replicate experiments