Effects of carbon source on growth and morphology of Botryococcus braunii

The green colonial alga Botryococcus braunii is characterized by the ability to produce and accumulate large amounts of hydrocarbons. We isolated and established an axenic clonal strain of B. braunii B70 and investigated the effects of organic carbon sources, including glucose, mannose, fructose, galactose, or acetate, on growth under light and dark conditions. This algal strain had the capacity to grow photo-, mixo-, or heterotrophically. Growth was promoted substantially following exposure of the algae to glucose or mannose under light exposure. Cells could grow under continuous darkness with glucose or mannose. In the presence of glucose under light or dark conditions, cell and colony size, and the intracellular granules containing oil, were markedly larger than those cultured without glucose.