title: 5-Aminolevulinic acid production in engineered Corynebacterium glutamicum via C5 biosynthesis pathway.
abstract: ALA (5-aminolevulinic acid) is an important intermediate in the synthesis of tetrapyrroles and the use of ALA has been gradually increasing in many fields, including medicine and agriculture. In this study, improved biological production of ALA in Corynebacterium glutamicum was achieved by overexpressing glutamate-initiated C5 pathway. For this purpose, copies of the glutamyl t-RNA reductase HemA from several bacteria were mutated by site-directed mutagenesis of which a HemA version from Salmonella typhimurium exhibited the highest ALA production. Cultivation of the HemA-expressing strain produced approximately 204 mg/L of ALA, while co-expression with HemL (glutamate-1-semialdehyde aminotransferase) increased ALA concentration to 457 mg/L, representing 11.6- and 25.9-fold increases over the control strain (17 mg/L of ALA). Further effects of metabolic perturbation were investigated, leading to penicillin addition that further improves ALA production to 584 mg/L. In an optimized flask fermentation, engineered C. glutamicum strains expressing the HemA and hemAL operon produced up to 1.1 and 2.2g/L ALA, respectively, under glutamate-producing conditions. The final yields represent 10.7- and 22.0-fold increases over the control strain (0.1g/L of ALA). From these findings, ALA biosynthesis from glucose was successfully demonstrated and this study is the first to report ALA overproduction in C. glutamicum via metabolic engineering.
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Ahmad Bazli
authors.initials: AB
authors.lastname: Ramzi
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Jeong Eun
authors.initials: JE
authors.lastname: Hyeon
authors.affiliation: Department of Chemical and Biological Engineering, Korea University, Seoul 136-701, Republic of Korea.
authors.forename: Seung Wook
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Republic of Korea.
authors.forename: Chulhwan
authors.initials: C
authors.lastname: Park
authors.affiliation: Department of Biotechnology, Korea University, Seoul 136-701, Republic of Korea. Electronic address: samhan@korea.ac.kr.
authors.forename: Sung Ok
authors.initials: SO
authors.lastname: Han
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000622:Aminolevulinic Acid / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D005798:Genes, Bacterial; D018698:Glutamic Acid / Q000378:metabolism; D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering; D009876:Operon; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D018698:Glutamic Acid; D000622:Aminolevulinic Acid; D000445:Aldehyde Oxidoreductases; C067282:glutamyl tRNA reductase; D019751:Intramolecular Transferases; C061049:glutamate-1-semialdehyde 2,1-aminomutase
keywords: 5-Aminolevulinic acid; C(5) pathway; Corynebacterium glutamicum; Glutamate; Glutamyl t-RNA reductase