Poly-B-hydroxybutyrate (PHB): A Biodegradable Polymer of Microbial Origin - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 53

Figure 3. Biological pathway of PHB production.
moleCular eXPressioNs oF PhB syNthesis GeNes
expression in Bacteria
Many studies have demonstrated heterologous expression of PHB synthases into bac-
teria. R. eutropha PHB -- 4 (Schlegel et al., 1970) and P. putida GPp104 (Huisman et al.,
1991) are defective in phaC gene used for physiological studies and cloning experi-
ments which require only PHB synthase gene for accumulation and expression of PHB
and such strains are easily identified by staining as mentioned earlier.
E. coli is the widely acceptable host for cloning experiments which offers a well
defined physiological environment for the production of recombinant proteins and
other bioproducts because this bacterium is widely studied in detail. Among the differ-
ent strains of E. coli, XL1 blue and E. coli XL - B have been the best for PHB production