New insights into the production of fucoxanthin by mixotrophic cultivation of Ochromonas and Microcystis aeruginosa

Fucoxanthin (Fx) has attracted great interest due to its remarkable biological activities such as antioxidant and anti-obesity, and its increasing demands in biopharmaceutical and cosmetic fields. However, its commercial production is limited by low yield and high cost. In this study, we isolated and identified a species of golden algae (Ochromonas sp.) capable of engulfing Microcystis aeruginosa (M. aeruginosa) and accumulating Fx. After 72 h mixotrophic cultivation of Ochromonas sp. and M. aeruginosa, the algal culture changed from green to yellow --brown, and the content of Fx and the daily production rate were up to 11.58 mg g-1, and 1.315 mg L-1 d(-1), respectively. The utilization rate of M. aeruginosa was 527.27 fg cell(-1). This study will not only provide a new thought to produce Fx in an efficient, low-cost, and sustainable way but an innovative method for the control and treatment of harmful cyanobacterial blooms from eutrophic freshwaters as well.

Automated summary

In this study, a strain of golden algae capable of engulfing Microcystis aeruginosa and accumulating Fucoxanthin (Fx) was isolated and identified. Under mixotrophic cultivation, the content and production rate of Fx in the algal culture significantly increased, along with a high utilization rate of Microcystis aeruginosa. This research is important not only for the efficient production of Fx, but also for addressing harmful cyanobacterial blooms in eutrophic freshwaters.