VG1(pTU14) is a novel recombinant Escherichia coli for Poly- β -hydroxybutyrate (PHB) production

which contains Vitreoscilla hemoglobin gene ( vgb )

lytic genes of phage λ( S -RRz ) and PHB biosynthetic genes ( phb CAB) in the cell.During the process of fed-batch culture of VG1 (pTU14)

it was found that the level of dissolved oxygen (DO)

the concentration ratio (C/N) and the range of carbon and nitrogen source were all important parameters affecting cell growth and PHB accumulation.DO and pH could be used to decide the time for the nutrition feeding.When C/N

carbon and nitrogen concentration were in the range of 10-20

10-40g·L -1

1.0-2.0g·L -1 respectively and DO was higher than 5%

the cell growth was enhanced.Otherwise

PHB accumulation would be enhanced too early to attain the high cell density culture.Finally

the optimal feeding strategy

by which the cell growth was emphasized in early process and the PHB accumulation was promoted in late process

was carried out.After 60h fed-batch culture under the optimal conditions

cell concentration

PHB concentration and PHB content were reached up to 215.9g·L -1

193.7?g·L -1 and 89.7%

respectively.