Abstract
Botryococcus braunii is a green colonial fresh water microalga that produces large amounts of hydrocarbons. This alga is classified into three races (A, B, and L), depending on the type of hydrocarbons synthesized. The B race produces triterpenoid hydrocarbons, referred to as botryococcenes, whereas the A race accumulates alkadienes and alkatrienes derived from fatty acids. The L race produces a tetraterpene hydrocarbon called lycopadiene. We reported the botryococcenes accumulated by B70 strain (race B) were derived from the MEP pathway in the 51st annual meeting. In this study, we isolated two genes (BbDXS1, BbDXS2) encoding 1-deoxy-D-xylulose 5-phosphate synthase (DXS), which catalyzed the first step of the MEP pathway. Two genes showed features similar to known DXS genes from other plants, including the presence of an N-terminal targeting sequence and a conserved thiamine pyrophosphate binding domain typical of transketolase-like sequences. The characterization of two DXSs was identified by the analysis of the recombinant enzymes. Further studies are now in progress to examine expression profiles of two DXS genes.
