Chemotaxonomic evidence for the similarity between Botryococcus braunii L race and Botryococcus neglectus

The hydrocarbon distribution patterns of nine strains of the green alga Botryococcus originating from four lakes and one pond are reported from GC- mass spectrometric analyses; they complement previously published investigations on Botryococcus braunii. Seven strains from four different origins (Australia, Bolivia, England and Portugal) contain very-long-chain hydrocarbons, mainly dienes and trienes, odd-carbon-numbered, ranging on the whole from C₂₃ to C₃₃; these compounds are characteristic of the A chemical race of B. braunii. Depending on the strain, a C₂₇, C₂₉ or C₃₁ prevalence is observed. In the Australian strains, the presence of n- C₂₉ and n-C₃₁ trienes exhibiting two conjugated double bonds in the midchain in a cis, trans configuration is reported for the first time in this alga. Two strains of Botryococcus neglectus isolated from a water sample collected in an Indian lake produce trans, trans-lycopadiene as the main hydrocarbon; this acyclic tetraterpenoid is typical of the L chemical race of B. braunii. This result strongly suggests that B. neglectus and B. braunii L race constitute the same taxa. The hydrocarbon contents vary from about 28% of the dry weight in the English strain to less than 0.1% in the Indian ones.