UV-C irradiation accelerates neutral lipid synthesis in the marine oleaginous diatom Fistulifera solaris.

This study investigated the induction of oil synthesis in the oleaginous diatom, Fistulifera solaris, following irradiation with small doses of UV-C. A rapid induction of oil accumulation was confirmed within 6h following UV-C radiation of the diatom cells, with increases in cell oil body volumes after 24h of approximately 4- to 6-fold from the initial volume. Reactive oxygen species (ROS), which can be generated by a UV-C-mediated reaction, were detected in irradiated cells and the correlation between ROS generation and oil accumulation was confirmed. The smallest UV-C intensity required for oil induction in the cells was 10mJ/cm2. Based on the ideal biodiesel profile, the most suitable FAME composition was obtained when UV255 was used to irradiate the cells. The UV-C radiation method is therefore a solution for shortening the oil accumulation period and improving biodiesel productivity.