Effect of culture conditions on production of 5-aminolevulinic acid by recombinant Escherichia coli.
Aminolevulinic acid (ALA) is formed by the enzyme ALA synthase (hemA gene). Then ALA is converted to Porphobilinogen (PBG) by the ALA dehydratase (hemB gene). For the overproduction of ALA, we used an Escherichia coli BL21(DE3) containing a hemA gene from Bradyrhzobium japonicum, which was created in our previous work. The effects of pH on the ALA synthase and ALA dehydratase were investigated. The ALA synthase and ALA dehydratase activities were dependent on the pH of the medium, with maximal activities occurring at pH 6.5 and 8.0 respectively. At pH 6.5, extracellular ALA reached 23 mM in a jar-fermenter. In addition, the effects of some nutritional factors, such as nitrogen source and the ratio of carbon to nitrogen (C/N) on the fermentative production of ALA were investigated. The highest ALA production was found with 8:1 of C/N ratio. Among various nitrogen sources, the tryptone might be a useful one for ALA production.
Lee
Dae-Hee
DH
Department of Food Science and Technology, Graduate School of Biotechnology, Korea University, Seoul.
Jun
Woo-Jin
WJ
Shin
Dong-Hoon
DH
Cho
Hong-Yon
HY
Hong
Bum-Shik
BS
D000624:5-Aminolevulinate Synthetase / Q000235:genetics; D000622:Aminolevulinic Acid / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D011995:Recombination, Genetic
D000622:Aminolevulinic Acid; D000624:5-Aminolevulinate Synthetase