Echinenone production of a dark red-coloured strain of Botryococcus braunii

Abstract

Echinenone has been used as an edible orange pigment, antioxidant and provitamin A. An echinenone-accumulating strain, BOT-20, of Botryococcus braunii was isolated from freshwater environments in Japan. The B. braunii BOT-20 strain is different from other strains of B. braunii, as it appeared dark red during its growth in the laboratory culture as opposed to green. The biomass of the strain was 1.9 g L−1 at 1 month after cultivation. The n-hexane/acetone (3:1, v/v) extract of the strain was 45.5% of the dry biomass weight and consisted of carotenoids (92%, of which 73% was echinenone) and hydrocarbons (8%). The echinenone content was 30.5% of the dry biomass weight, and production was 630 mg L−1. Hydrocarbons comprised only 3.7% of the total dry biomass weight. The main component of hydrocarbon was an analogue of botryococene by 1H and 13C NMR. With high values of echinenone content and production, the B. braunii strain BOT-20 is expected to be a new bioresource for the commercial production of echinenone.