With the global economic development, the use of plastic has increased significantly. Currently, over 8.3 Gt of plastic is produced annually and approximately 6.3 Gt is discarded. Furthermore, 99% of the plastic is obtained from petroleum. When the plastic is obtained from petroleum, the carbon moves in one direction from the underground into the atmosphere in the form of CO2 gas, which is unsustainable, thereby requiring the development of a carbon recycling process that is independent of oil. The plastic waste is inadequately treated, which results in a substantial amount of plastics being released into the environment, thereby creating micro- and nano-plastic problems. Although bioplastics, such as polylactic acids, polyhydroxyalkanoates, and polybutylene succinate, are being actively researched and developed as alternatives to petroleum-based plastics, they have not been able to replace petroplastics yet due to their complex production processes and high cost. Therefore, we develop an alternative method for manufacturing bioplastics, wherein cells of unicellular green algae are used as the raw material; the plastics obtained are known as cell-plastics. The direct use of green algal cells for plastic production has several advantages. Through photosynthesis, green algae use CO2 as the carbon source to construct new cells; therefore, depending on the rate of CO2 assimilation, the growth activity of the grown cell is greater than that of the ordinary terrestrial plants. Algal cells have shown potential for application in robust cell-plastics owing to their rigid cell wall structure. Although cell-plastics are currently under trial in laboratory, we believe that they will be suitable for industrial-scale production.
Sustainable society; Carbon recycle; Bioplastics; Unicellular green alga; Cell-plastics