Strain F41 malE :: pyc. The mutant F41malE::pyc has a deletion of the two pyruvate kinase (Pyk) genes pykA and pykF, of the phosphoenolpyruvate carboxylase (Ppc) and an insertion of pyruvate carboxylase (Pyc). On the agar plate, F41malE::pyc was not able to grow on glycerol minimal media and was compared to the wild type LJ110 wt. With additional lactate, F41malE::pyc grew. Various endogenous pathways may lead to pyruvate prototrophy.