Fig. 2From: Engineering a vitamin B12 high-throughput screening system by riboswitch sensor in Sinorhizobium melilotiConstructed engineered mutants with different production capacities. a Oxygen-dependent VB12 biosynthetic pathway in S. meliloti. The branched biosynthesis of heme is also depicted. b The concentration of VB12 in producer strains in fermentation broth was determined by HPLC. Different colors represent the different strains. Values shown are HPLC-determined and are the means of three independent fermentation cultures for each strain. c the amount of intracellular VB12 in recombinant strains in (b)Back to article page