Microalgae to bioplastics – Routes and challenges

There is an increasing interest in the production of bioplastics from biomass-based feedstocks to address the challenges associated with increasing global plastic consumption. Bioplastics are produced mainly from 1st generation feedstocks that compete with food production for agricultural resources. Recently, microalgae have gained interest as a feedstock for bioplastics production. Microalgae can be used in various ways to produce different types of bioplastics including various biodegradable and drop-in bioplastics. However, not much attention has been paid to different routes of bioplastics production from microalgae. This review examines the potential of using microalgae as a feedstock for bioplastics, with a focus on three key polymer synthesis routes: 1) use of natural polymers synthesised by microalgae, 2) chemical synthesis of polymers from microalgae-derived feedstocks and 3) microbial synthesis of polymers from microalgae-derived feedstocks. The technical and economic challenges associated with each route are analysed. The optimal route of using microalgae as a feedstock for bioplastics largely depends on the economics of the process. Conducting comparable feasibility studies for various routes is recommended to identify the most economically viable route for utilising microalgae to produce bioplastics. Microalgae has great potential for the bioplastic industry, however, to progress the research to commercialisation, future research emphasis should be placed on investigating various routes of utilising microalgae for bioplastics along with optimising the process for enhanced biomass productivity and polymer yield, characterising the produced polymers, investigating the co-production of bioplastics with other products, and integrating the production of bioplastics with the wastewater treatment.