Effect of anaerobic promoters on the microaerobic production of polyhydroxybutyrate (PHB) in recombinant Escherichia coli.
Nine anaerobic promoters were cloned and constructed upstream of PHB synthesis genes phbCAB from Ralstonia eutropha for the micro- or anaerobic PHB production in recombinant Escherichia coli. Among the promoters, the one for alcohol dehydrogenase (PadhE) was found most effective. Recombinant E. coli JM 109 (pWCY09) harboring PadhE and phbCAB achieved a 48% PHB accumulation in the cell dry weight after 48 h of static culture compared with only 30% PHB production under its native promoter. Sixty-seven percent PHB was produced in the dry weight (CDW) of an acetate pathway deleted (Deltapta deletion) E. coli JW2294 harboring the vector pWCY09. In a batch process conducted in a 5.5-l NBS fermentor containing 3 l glucose LB medium, E. coli JW2294 (pWCY09) grew to 7.8 g/l CDW containing 64% PHB after 24 h of microaerobic incubation. In addition, molecular weight of PHB was observed to be much higher under microaerobic culture conditions. The high activity of PadhE appeared to be the reason for improved micro- or anaerobic cell growth and PHB production while high molecular weight contributed to the static culture condition.
Wei
Xiao-Xing
XX
MOE Laboratory for Protein Sciences, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China.
Shi
Zhen-Yu
ZY
Yuan
Mei-Qing
MQ
Chen
Guo-Qiang
GQ
D000332:Aerobiosis; D000693:Anaerobiosis; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D020118:Cupriavidus necator / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005818:Genetic Engineering; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011401:Promoter Regions, Genetic
D001426:Bacterial Proteins; D011108:Polymers; C111948:poly(hydroxyethanoate)