Rapid Sorting of Fucoxanthin-Producing Phaeodactylum tricornutum Mutants by Flow Cytometry

Fucoxanthin, which is widely found in seaweeds and diatoms, has many benefits to human health, such as anti-diabetes, anti-obesity, and anti-inflammatory physiological activities. However, the low content of fucoxanthin in brown algae and diatoms limits the commercialization of this product. In this study, we introduced an excitation light at 488 nm to analyze the emitted fluorescence of Phaeodactylum tricornutum, a diatom model organism rich in fucoxanthin. We observed a unique spectrum peak at 710 nm and found a linear correlation between fucoxanthin content and the mean fluorescence intensity. We subsequently used flow cytometry to screen high-fucoxanthin-content mutants created by heavy ion irradiation. After 20 days of cultivation, the fucoxanthin content of sorted cells was 25.5% higher than in the wild type. This method provides an efficient, rapid, and high-throughput approach to screen fucoxanthin-overproducing mutants.

Automated summary

This study introduces a new method for screening mutants with high fucoxanthin content, successfully identifying a linear correlation between content and fluorescence intensity in the diatom model organism rich in fucoxanthin. By using flow cytometry, high-fucoxanthin-content mutants were sorted out, with a significant increase in fucoxanthin content compared to the wild type after 20 days of cultivation. This efficient, rapid, and high-throughput approach provides a valuable tool for screening fucoxanthin-overproducing mutants.