Fig. 1

Metabolic pathway of isobutanol synthesis and branch pathway in K. pneumoniae. Kp-IpdC is catalysing the 2-ketoisovalerate decarboxylation and further conversion to isobutanol (blue route). It was suspected that the pyruvate decarboxylase activity of Kp-IpdC reduced the available pyruvate for isobutanol synthesis (red route)