title: Heterologous expression of glutamyl-tRNA reductase gene inRhodobacter sphaeroidesO.U.001 to enhance 5-aminolevulinic acid production.
abstract: The pathways for synthesis of 5-aminolevulinic acid (5-ALA) use either succinyl-CoA and glycine (C-4 pathway), or glutamate (C-5 pathway). AlthoughRhodobacter sphaeroidessynthesizes 5-ALA through the C-4 pathway, it also has the genes coding for the enzymes of the C-5 pathway, except for glutamyl-tRNA reductase. The glutamyl-tRNA reductase gene was cloned fromRhodospirillum rubrumand expressed inR. sphaeroides; thus, the C-5 pathway was enabled to function upon assembling all the required genes. Consequently, a new and unique bacterial strain producing more 5-ALA was developed. Biohydrogen was also produced in the same bioprocess within a biorefinery approach using sugar beet molasses as substrate. The amount of 5-ALA produced by the modified strain was 25.9 mg/g dry cell weight (DCW), whereas the wild-type strain produced 12.4 mg/g DCW. In addition, the amount of H2generated by the modified and wild-type cells, respectively, was 0.92 L/L culture and 1.05 L/L culture.
authors.affiliation: Department of Biology, Faculty of Science, Selçuk University , Konya , Turkey.
authors.forename: Gökhan
authors.initials: G
authors.lastname: Kars
authors.affiliation: Department of Biology, Faculty of Science, Selçuk University , Konya , Turkey.
authors.forename: Ümmühan
authors.initials: Ü
authors.lastname: Alparslan
keywords: Rhodobacter sphaeroides O.U.001; aminolevulinic acid; biohydrogen; glutamyl-tRNA reductase; heterologous expression