Salomon. E1, Tal S1, Ogen-Shtern N2, 3
1Israel Oceanographic and Limnological Research, National Center for Mariculture, POB 1212 Eilat, Israel, 2Dead Sea and Arava Science Center, Dead Sea Branch, Massada National Park, Israel, 3Eilat Campus, Ben Gurion University of the Negev, Eilat, Israel
Correspondence: Eitan Salomon, eitansol@ocean.org.il
The worldwide supply of agar comes exclusively from a few red seaweed genera and especially from the Gracilaria genus, mostly grown in shallow beaches or tide pools (FAO2018). In recent years, red seaweeds have gained further interest as a potential source for health promoting substances, such as antioxidant and anti-inflammatory agents. In our research, we explored the effects of several factors on the growth rates and agar yields of the tropical seaweed Gracilaria cornea, grown in a specially designed outdoor tank system, for better control over cultivation conditions.
Our finding indicated that an addition of artificial LED illumination for a period of 14 hours, during the day, significantly enhanced growth rates of G. cornea. Surprisingly, a supply of air bubbling—a common, expensive practice in offshore seaweed growth systems—had no significant effect on growth rates when compared to G. cornea grown without bubbling.
Additionally, a series of G. cornea extractions were verified to be safe for topical application on ex vivo human skin explants. Some of these extractions were very potent in reducing the inflammatory response of human skin cells to either air pollution or UVB exposure, in a dose dependent manner.
Overall, our results provide important information for current and potential Gracilaria growers seeking to improve their yields while lowering the cultivation costs. Our results also show that G. cornea has a potential commercial value not just as a source for agar, but also as a natural, plant-based source of health promoting ingredients for the skin care industry.