ABSTRACT
A recombinant E. coli XL1-Blue (pKSSE5.3) habouring PHA sythase gene (phaC) of Ralstonia eu-tropha H16 and 4-hydroxybutyric acid: CoA transferase gene (orfZ) of Clostridium kluyveri was used to produce poly (4-hydroxybutyric acid), P (4HB), homopoiyester in M9 salts medium with glucose and 4-hydroxybutyric acid as carbon sources. Optimization of medium type and cultivation conditions and fed-batch culture were carried out. The results showed that the final cell dry weight, P (4HB) concentration and P (4HB) content were 13 g/L, 5g/L, and 36%, respectively in a 27L stirred and aerated fermentor after 68 hours of fed-batch culture. A large amount of P (4HB) was isolated by extraction of lyophilized cells with chloroform and make it possible to further examine the material properties and applications of P (4HB) homopoiyester from recombinant E. coli.