[Inverted metabolic engineering of E.coli to produce PHB and simplifying of lysis process; using gene E from phage PhiX 174]

ABSTRACT

The polyhydroxybutyrate biosynthetic genes of Ralstonia eutropha are organized in single operon. There are many studies which show that this operon could be cloned in gram negative bacteria like E.coli. As its original promoter could work efficiently in E.coli, there is no need to change it with host ones. Granule extraction is one of the most important considerations of industrial production of PHB. Solvent base or physical approaches increase the cost of production and compromise the integrity of PHB granules. Therefore, E mediated lysis was used in this study to extract the granules. In this study, the whole operon of PHB from Ralstonia eutropha and E gene from phage phiX174 were obtained by PCR technique, and cloned transferred to E.coli by separate plasmids. To control the lysis process, the chemical inducible system was used. Bacterial cells which have both plasmids could produce high levels of PHB, and their PHB content could be released into the medium, nearly perfectly, at the correct time by adding IPTG as a chemical inducer. This method could be used to produce and extract PHB with more cost effectiveness in industrial scales