Fig. 1

Metabolic pathways of interest leading to the synthesis of d-lactate from glycerol. The enhanced and blocked pathways were highlighted in blue (solid line) and red (dotted line), respectively. Genes and key metabolites involved in metabolic pathways include as follows: aceE-lpd, pyruvate dehydrogenase; adhE, aldehyde–alcohol dehydrogenase; dld, FAD-linked d-lactate dehydrogenase; dhaKLM, dihydroxyacetone kinase operon; frdABCD, fumarate reductase operon; ldhA, NAD-linked d-lactate dehydrogenase; D-ldh, L. helveticus d-lactate dehydrogenase; mgsA, methylglyoxal synthase; narGHJI, nitrate reductase operon; ndh, NADH dehydrogenase; poxB, pyruvate oxidase; gldA, glycerol dehydrogenase; glpD, glycerol 3-phosphate dehydrogenase; glpK, glycerol kinase; pflB, pyruvate-formate lyase; pflDC, putative pyruvate-formate lyase; pta, phosphate acetyltransferase; ACE acetate, CIT citrate, DHAP dihydroxyacetone phosphate, EtOH ethanol, FOM formate, α-KG α-ketoglutarate, D-LAC d-lactate, L-LAC l-lactate, OAA oxaloacetate, PEP phosphoenolpyruvate, PYR pyruvate, SUC succinate, SCN-CoA succinyl-CoA, UQ ubiquinone