Isolation of High-Lipid Tetraselmis suecica Strains Following Repeated UV-C Mutagenesis, FACS, and High-Throughput Growth Selection

Mutagenesis and selection of microalgae can be used for accelerated breeding of elite strains, providing a significant advantage over genetic engineering as prior biochemical and genetic information is not required. Ultraviolet (UV)-C-induced mutagenesis combined with fluorescence-activated cell sorting (FACS) and microtiter plate reader cell density screening was used to produce Tetraselmis suecica strains with increased lipid contents without compromising on cell growth. After five rounds of mutation-selection, two dosages of UV-C (50 and >98 % lethality) yielded two improved strains (M5 and M24) that produced significantly more neutral lipids (increases of 114 and 123 %, respectively). This study highlights that repeated UV-C mutagenesis and high-throughput selection for cell growth can be a viable combined approach to improve lipid productivity in microalgae. These maybe used as elite strains for future breeding programs and as potential feedstock for biodiesel production.