Carbon sequestration by recombinant carbonic anhydrase in Ralstonia eutropha

Emission of greenhouse gases and plastic wastes are one of the most important environmental problems in the world. The purpose of this study was to use the bacterium Ralstonia eutropha as the host for recombinant carbonic anhydrase enzyme which is used for carbon sequestration and poly hydroxyl butyrate (PHB) production. The carbonic anhydrase gene (CA) was inserted in the expression vector and transformed into Ralstonia eutropha. Then PHB production was assayed by FT-IR and GC-MS methods in recombinant and non-recombinant bacteria in different concentrations of LB medium in the presence and absence of CO2. Production of PHB in LB medium increased 31.49 percent in recombinant bacteria in the presence of CO2.  These increases were 18.44 and 34.44 percent compared to non-recombinant bacteria in presence and absence of CO2, respectively. In 0.5 LB medium, the recombinant bacterium produced 26.57 percent PHB in presence of CO2 more than in its absence.  Non-recombinant bacterium in this medium produced 18.30 and 30.63 percent PHB less than the recombinant cell in the presence and absence of CO2, respectively. The quantity of PHB production using GC-MS revealed that CA gene expression was effective for increasing PHB production in recombinant R. eutropha. In the presence of CO2 and by using a simple medium. The recombinant bacterium is able to produce PHB. This bacterium can also be effective in carbon sequestration.