Chapter 7. Genetic Engineering of Microalgae for Enhanced Photosynthetic Efficiency, CO2 Fixation, and Fuel-based Products

The rapid increase in global energy demand, as well as global warming and climate change, has fuelled the search for alternative renewable energy sources with lower environmental impact. Microalgae have enormous potential as renewable energy feedstocks. Microalgal biomass can be used to produce a variety of biofuels, including biodiesel, bioethanol, bio-hydrogen, bio-methane, and syngas. Reducing carbon dioxide (CO2) emissions has been a major research objective in recent years. As an environmentally responsible technique, the integration of microalgae cultivation utilizing CO2 from power plants and other industries has been introduced. However, strains with high biomass production are necessary to build a sustainable integrated platform. Improving photosynthesis is crucial for increasing both biomass productivity and CO2 sequestration efficiency. Photosynthesis is frequently improved by increasing the efficiency of enzymes involved in CO2 fixation, reducing antenna size to avoid energy loss, extending the photosynthetically active radiation range to broaden the light utilization capacity, increasing CO2 assimilation by replacing the existing carbon fixation pathway with more efficient pathways and enzymes, and reducing the release of captured CO2. These changes can be implemented through transformation and gene editing. Transformation of novel gene constructs into microalgae has been described as an incredibly difficult challenge throughout the last decade. The current chapter extensively covers various solutions for improving microalgal CO2 fixation, provides insight into present limitations/gaps, and proposes future perspectives of microalgal biotechnology.