Metabolic Regulation Of Polyhydroxyalkanoates And Construction Of Genetically Engineered Bacterium

PoIyhydroxyalkanoates(PHAs) are polymers that are produced by diverse bacteria and that accumulated as intracellular granules. It has not only the characteristic of petrochemical plastics but also has the biodegradability, biocompability and degradable product without toxin. These biologic polymers are new kinds of environment -friendly material that provide a new way to resolve White Pollution and can be used as scaffold material in medical tissue engineering. On the basis of our research on synthesis of polyhdyoxybutyrate(PHB), S.fredii is able to accumulate P(HB-HH) and P(HB-HO) when grown with alkanoates as regulator. P(HB-HH) and P(HB-HO) was considered as new kinds of PHAs. Especially, P(HB-HO) was a newly synthesize biologic material. Principium process was established through research on correlative parameter of metabolic regulation in fermentation process. S.fredii can synthesize PHB in culture medium of glucose and change its metabolic pathway by intimidation pressure when alkanoates were added into culture medium. According to this theory , metabolic pathway of P(HB-HH) was induced. Due to the physical and biologic property of P(HB-HH) and P(HB-HO),they provide a wide prospect of application in medical tissue engineering. Furthermore, genetic engineering bacteria which can synthesize P(3HB-4HB) is being constructed. E.coli harboring orfz gene was used as a provider of pTn5cat transposon vector and S.fredii was used as a acceptor. A kind of triplepolymer will possibly be synthesized by metabolic regulation in S.fredii. A new series of PHAs products will be exploited.