Characterization of Chlamydomonas Very High Light-tolerant Mutants for Enhanced Lipid Production

Abstract

Introduction Biodiesel from microalgae is still not available commercially due to the high cost of production. Most commercial cultivation of microalgae utilize open pond systems as they are easy and inexpensive to construct 1 , but one of the disadvantages is uncontrollable light intensity that could lead to oxidative stress and eventually biomass reduction. In outdoor conditions, light intensity gradually increases from sunrise to midday with around 2,000 μmol photons m 2 s 1 and then gradually decreases towards sunset. Furthermore, light intensity is highest around the equator and decreases with increasing distance from the equator to the poles. Light is absolutely essential for algal growth, and different strains require different amounts of light for maximal growth, whereas excessive light is harmful. When excess light is absorbed, damage to the photosynthetic apparatus may be induced, which results in the reduction of photosynthetic capacity and changes in pigment concentrations 2, 3. Exposure of photosynthetic organisms to

Microalgae biofuels: illuminating the path to a sustainable future amidst challenges and opportunities

“…Hence, strains with high light-tolerance are ideal for large-scale production systems in outdoor conditions. Study of two high-light-tolerant Chlamydomonas mutants supported this claim, showing that their lipid productivity increased twice as much as that of the wild type under high-light conditions [ 143 ].…”

Characterization of Chlorella sorokiniana and Chlorella vulgaris fatty acid components under a wide range of light intensity and growth temperature for their use as biological resources

“…Therefore, it is important to select a suitable species for biomass production of microalgae using the open pond type raceway system ( Isdepsky and Borowitzka, 2019 ; Rayen et al., 2019 ) and one which can adapt to conditions of high light intensity and temperature ( Lee et al., 2018 ; Rayen et al., 2019 ; Akizuki et al., 2020 ). Such environmental conditions have been shown to increase the lipid and saturated fatty acid content of microalgae ( Han et al., 2016 ; Hong et al., 2019 ; Yaisamlee and Sirikhachornkit, 2020 ), further suggesting the importance of adaptation to these conditions in the microalgal species we aim to select.…”