Improved fucoxanthin and docosahexaenoic acid productivities of a sorted self-settling Tisochrysis lutea phenotype at pilot scale

Improved high-throughput screening technique to rapidly isolate Chlamydomonas transformants expressing recombinant proteins

“…FACS has recently become an important tool in the microalgal biotechnology field, as it can be used in bioprospecting for novel strains, achieving axenic cultures, and in strain improvement by enrichment of cells with specific properties; however, the majority of previous studies have focused on screening for lipid-rich microalgae, rather than other gene products and biomolecules (Pereira et al 2018 ). The technique has more recently been demonstrated for wider applications, such as screening of the microalga T. lutea , which allowed production of the valuable compounds fucoxanthin (Fx) and docosahexaenoic acid (DHA) to reach industrial levels at outdoor pilot scale after only two rounds of FACS (Gao et al 2020 ; Gao et al 2021 ). Continued development of FACS methods for screening improved algal strains in this manner will more rapidly advance the field of microalgal biotechnology for a larger diversity of commercial bioproducts.…”

Dynamical Darwinian selection of a more productive strain of Tisochrysis lutea

“…Alternatively, the selected population may be screened to isolate clones with the desired phenotype. This additional step will prevent individuals in minority to outcompete the strain of interest [55]. Lastly, cryopreserving the selected microalgae will guarantee the conservation of the sought-after properties when inoculating a new reactor.…”

Random Mutagenesis as a Promising Tool for Microalgal Strain Improvement towards Industrial Production

“…Wang et al [141] managed to increase the EPA content of Phaeodactylum tricornutum cells to 139 µg/mg biomass using hyposaline and fulvic acid treatments (Table 2). Tisochrysis lutea 2 rounds of direct evolution + FACS Carotenoid and fatty acid content 3.1-fold fucoxanthin and 1.6-fold DHA higher productivities [29] Scientists are also focusing on the development of strains able to perform bioremediation, which have to be robust and able to grow in media with high amounts of potentially harmful compounds (e.g., phenol, NOx, SOx, and CO 2 ) in order to remove them from the environment. For example, Cheng et al [78] improved a Chlorella strain through an adaptive laboratory evolution of 46 cycles to flue gas, which developed tolerance and became able to grow exposed to the aforementioned pollutants (Table 2).…”

“…As with random mutagenesis, researchers aimed to improve the biochemical profile of the microalgae, namely carotenoids and fatty acids, while maintaining or improving their growth rate ( Table 2 ). Regarding biochemical improvements, Gao et al [ 29 ] have recently reported the isolation of an improved Tisochrysis lutea with only two rounds of FACS based selection using fucoxanthin fluorescence, of which fucoxanthin and DHA contents were 3.1 and 1.6-fold higher, respectively ( Table 2 ). Wang et al [ 141 ] managed to increase the EPA content of Phaeodactylum tricornutum cells to 139 µg/mg biomass using hyposaline and fulvic acid treatments ( Table 2 ).…”

“…The first step towards this purpose begins with bioprospection and selection of strains with improved features and enhanced biomass and target biomolecule productivities. High-throughput technologies, such as methods based on fluorescence-activated cell sorting (FACS), are powerful tools to mine and isolate improved strains [ 13 , 27 , 28 , 29 ]. Nonetheless, to pursue large-scale production and profitability, such strains require further improvement.…”