Engineering of a glycerol utilization pathway for amino acid production by Corynebacterium glutamicum

The amino acid-producing organism Corynebacterium glutamicum cannot utilize glycerol, a stoichiometric by-product of biodiesel production. By heterologous expression of Escherichia coli glycerol utilization genes, C. glutamicum was engineered to grow on glycerol. While expression of the E. coli genes for glycerol kinase ( glpK ) and glycerol 3-phosphate dehydrogenase ( glpD ) was sufficient for growth on glycerol as the sole carbon and energy source, additional expression of the aquaglyceroporin gene glpF from E. coli increased growth rate and biomass formation. Glutamate production from glycerol was enabled by plasmid-borne expression of E. coli glpF, glpK , and glpD in C. glutamicum wild type. In addition, a lysine-producing C. glutamicum strain expressing E. coli glpF, glpK , and glpD was able to produce lysine from glycerol as the sole carbon substrate as well as from glycerol-glucose mixtures.