(166k) Conversion of CO2 to Bioplastics By a Sequential Cultivation of Clostridium Formicoaceticum and Pseudomonas Putida

CO₂, a greenhouse gas is currently being emitted in large amounts due to increasing industrialization and population increase, thereby causing global climate change which is a major threat to our planet. Along with climate changes, the world is also facing environmental deterioration due to the accumulation of petroleum-based plastics. In this research, our aim is to sequester atmospheric CO₂ and convert it into polyhydroxyalkanoates (PHAs) through bacteria cultivation of Clostridium formicoaceticum ATCC 27076 and Pseudomonas putida KT2440. P. putida KT2440 can produce PHA but cannot feed on formate as the sole carbon source because it has no pathway to shuttle formate into central metabolism. Hence we employed C. formicoaceticum to first covert formate into acetate. C. formicoaceticum ATCC 27076 was fermented using different concentrations of pure formate as substrate. Only 5 g/L and 10 g/L produced a significant amount of acetate, 2.4 g/L and 5.3 g/L were produced respectively. These acetates were then used as the sole carbon source by P. putida KT2440 to produce PHAs. Afterward, 11 g/L of formate derived from CO₂ was then used and produced 9.6 g/L acetate. The obtained acetate was also used by P. putida KT2440 to produce PHAs. This work showed the entire process from CO₂, a deleterious gas in the environment to bioplastics (PHAs). It pointed out a direction of reducing CO₂ level in the atmosphere and in the meantime producing useful biodegradable plastics.