[The construction of a recombined E. coli strain with stable and high production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)].

Plasmid pJMC2 was constructed by cloning the parDE fragment of RK2 into pTZ18U-PHB which harbored phaCAB from Alcaligenes eutrophus and was transferred into E. coli HMS174 and E. coli JM107 separately. It is very stable in its hosts cultured in medium without ampicillin. E. coli HMS 174(pTZ18U-PHB) and E. coli JM107(pTZ18U-PHB) produced P(3HB-co-3HB) in a low phosphate concentration medium(18 mmol/L). The proportion of 3-hydroxyvalerate(3HV) in the polymer was 5%-8%. A fed-batch culture of E. coli HMS174(pJMC2) was conduct in a 5 L automatically controlled fermentor, the final dry cell weight, P(3HB-co-3HV) content, and th 3HV proportion were 42.5 g/L, 70% and 4.9% respectively.