Microalgae are one of the dominant groups of phytoplankton in oceans and account for more than 50% of global primary production. They are regarded as one of the most promising platform assets for sustainable production of petrochemical substitutes and bioactive compounds. However, a prerequisite to achieving this goal is to increase the solar-to-biomass conversion efficiency of photosynthesis, which remains less than 5% for most photosynthetic organisms. Photosynthesis plays a central role in enabling a bioeconomy to become sustainable and feasible to human beings. To enhance photosynthesis while alleviating CO2 emissions, we first conducted adaptive laboratory evolution in microalgae and then successfully provided the means to evolve green microalgae and diatoms with enhanced photosynthetic efficiency as well as increased carotenoids accumulation using designed LEDbased photobioreactors. We further developed and implemented a rapid and effective approach, named as intracellular spectral recompositioning (ISR) of light, which, through absorption of excess blue light and its intracellular emission in the green spectral band, can improve light utilization. We demonstrate that ISR-based eGFP transformants of the model diatom Phaeodactylum tricornutum could outperform their wild-type parental strain by 50% in biomass production rate under simulated outdoor sunlight conditions. We also identified key photosynthesis genes as well as major non photochemical quenching (NPQ) genes involved in light stress response, which may contribute to the enhancement of photosynthesis in engineered P. tricornutum strains. Our findings demonstrate the feasibility of developing more efficient photosynthetic cell factories to produce algae-based bioactive compounds and biofuels while addressing global CO2 emission issues.
Meeting ID: 945 5897 8222