Potential advancement of ultraviolet-free solar radiation technology in enriching the nutrient composition and biodiesel feedstock production in marine green microalga Platymonas subcordiformis

Abstract Outdoor cultivation was carried out on a site very near to the Tropic of Cancer (23°26′21.45″) to investigate the effects of solar radiation on the growth, nutrient composition and biodiesel feedstock production of a marine green microalga Platymonas subcordiformis. During a 7-day period of exposure to sunlight in the winter, ultraviolet-free solar radiation (UVFSR) significantly increased the accumulation of total carotenoids and individual carotenoids including zeaxanthin, fucoxanthin and violaxanthin in P. subcordiformis when compared with the full spectrum solar radiation (FSSR). UVFSR treatment also resulted in significantly higher levels of palmitoleic acid, a main biodiesel feedstock, and eicosapentaenoic acid in the microalga than that of FSSR. Removal of the ultraviolet spectrum from the solar radiation (UVFSR technology) show its potential advantage for increasing the production of microalgal nutrient components including carotenoids and specific polyunsaturated fatty acids, as well as biodiesel feedstock, for the applications of attractive bioresources.