Desiccation tolerance of Botryococcus braunii (Trebouxiophyceae, Chlorophyta) and extreme temperature tolerance of dehydrated cells

• Published in: Journal of applied phycology 2014-02, Vol.26 (1), p.49-53
• Main Authors: Demura, Mikihide, Ioki, Motohide, Kawachi, Masanobu, Nakajima, Nobuyoshi, Watanabe, Makoto M
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Botryococcus; Botryococcus braunii; Brackish; Brackish water; Chlorophyta; Desiccation; Ecology; Freezing; freshwater; Freshwater & Marine Ecology; fuels; High temperature; hydrocarbons; Life Sciences; microalgae; Plant Physiology; Plant Sciences; polysaccharides; Renewable fuels; Saccharides; temperature; Trebouxiophyceae
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-013-0059-7

Botryococcus braunii Kützing, a green colonial microalga, occurs worldwide in both freshwater and brackish water environments. Despite considerable attention to B. braunii as a potential source of renewable fuel, many ecophysiological properties of this alga remain unknown. Here, we examined the desiccation and temperature tolerances of B. braunii using two newly isolated strains BOD-NG17 and BOD-GJ2. Both strains survived through 6- and 8-month desiccation treatments but not through a 12-month treatment. Interestingly, the desiccation-treated cells of B. braunii gained tolerance to extreme temperature shifts, i.e., high temperature (40 °C) and freezing (−20 °C). Both strains survived for at least 4 and 10 days at 40 and −20 °C, respectively, while the untreated cells barely survived at these temperatures. These traits would enable long-distance dispersal of B. braunii cells and may account for the worldwide distribution of this algal species. Extracellular substances such as polysaccharides and hydrocarbons seem to confer the desiccation tolerance.