Development of polyhydroxybutyrate biosynthesis in Bacillus subtilis with combination of PHB-associated genes derived from Ralstonia eutropha and Bacillus megaterium

Polyhydroxybutyrate (PHB) is a biodegradable polymer synthesized by bacteria for carbon storage in response to environmental stress. B. subtilis is generally recognized as a safe Gram-positive bacterium and is widely used for industrial-scale production of proteins and chemicals. Owing to lack of toxic lipopolysaccharides, B. subtilis is a superior alternative to the Gram-negative bacteria presently used for PHB production. In this study, we introduced PHB synthesis genes from R. eutropha and B. megaterium into B. subtilis for PHB production. The highest yield of PHB was achieved by coexpression of phaA from R. eutropha and phaR, phaB, and phaC from B. megaterium (up to 13.02% ± 1.67% of total cell dry weight in LB medium containing 1% glucose). The results indicate that B. subtilis is potentially used as a safe vehicle for producing PHB.