title: Microbial Synthesis of 5-Aminolevulinic Acid and Its Coproduction with Polyhydroxybutyrate.
abstract: 5-Aminolevulinic acid (ALA), an important cell metabolic intermediate useful for cancer treatments or plant growth regulator, was produced by recombinant Escherichia coli expressing the codon optimized mitochondrial 5-aminolevulinic acid synthase (EC: 2.3.1.37, hem1) from Saccharomyces cerevisiae controlled via the plasmid encoding T7 expression system with a T7 RNA polymerase. When a more efficient autoinduced expression approach free of IPTG was applied, the recombinant containing antibiotic-free stabilized plasmid was able to produce 3.6 g/L extracellular ALA in shake flask studies under optimized temperature. A recombinant E. coli expressing synthesis pathways of poly-3-hydroxybutyrate (PHB) and ALA resulted in coproduction of 43% PHB in the cell dry weights and 1.6 g/L extracellular ALA, leading to further reduction on ALA cost as two products were harvested both intracellularly and extracellularly. This was the first study on coproduction of extracellular ALA and intracellular PHB for improving bioprocessing efficiency. The cost of ALA production could be further reduced by employing a Halomonas spp. TD01 able to grow and produce ALA and PHB under continuous and unsterile conditions even though ALA had the highest titer of only 0.7 g/L at the present time.
authors.affiliation: Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University , Beijing 100084, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Li
authors.affiliation: Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University , Beijing 100084, China.|Center for Synthetic and Systems Biology, Tsinghua University , Beijing 100084, China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Guo
authors.affiliation: Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University , Beijing 100084, China.
authors.forename: Guan-Qing
authors.initials: GQ
authors.lastname: Qiao
authors.affiliation: Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University , Beijing 100084, China.|Center for Synthetic and Systems Biology, Tsinghua University , Beijing 100084, China.|MOE Key Lab of Industrial Biocatalysis, Tsinghua University , Beijing 100081, China.
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Chen
mesh_terms: D000622:Aminolevulinic Acid / Q000378:metabolism*; D053898:Biosynthetic Pathways; D003001:Cloning, Molecular; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D020632:Halomonas / Q000235:genetics / Q000378:metabolism; D006885:Hydroxybutyrates / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011091:Polyesters / Q000378:metabolism*; D015202:Protein Engineering; D012242:Rhodobacter sphaeroides / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D000094122:Polyhydroxybutyrates
chemical_list: D000622:Aminolevulinic Acid; D012321:DNA-Directed RNA Polymerases; D006885:Hydroxybutyrates; D011091:Polyesters; D029701:Saccharomyces cerevisiae Proteins; D014764:Viral Proteins; C107955:poly(4-hydroxybutanoate); C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C062210:bacteriophage T7 RNA polymerase
keywords: 5-aminolevulinic acid; Escherichia coli; Halomonas; PHB; Saccharomyces cerevisiae; T7 RNA polymerase; synthetic biology