Outdoor open pond batch production of green microalga Botryococcus braunii for high hydrocarbon production: enhanced production with salinity

摘要

The aim of this work was to enhance the biodiesel quality and hydrocarbon content of green microalga B. braunii strain KMITL 2 cultivated outdoor under several salinity conditions in a batch production. The enhancement would be such that the microalgal biodiesel qualities met or exceeded the current standard so that it would be a good raw material for biodiesel production. The microalga production was in 300?L open oval ponds, among various salinity levels tested (0–20 ppt), 5 ppt was the best for hydrocarbon production, yielding 54.2?±?0.9% hydrocarbon content and 5.1?±?0.4?g?L?1 biomass. As the microalga production was scaled up by cultivation in 3,675?L open raceway pond under the 5 ppt condition, the microalga yielded a bit higher hydrocarbon content (58.8?±?2.9%) but much lower biomass (2.5?±?0.5?g?L?1). The production in both oval and raceway ponds yielded a nearly identical biodiesel property (61.06–67.42 cetane number) which exceeded the value specified in international standards. Therefore, it was concluded that B. braunii strain KMITL 2 can be batch cultivated in an open pond at optimum salinity to yield sufficient hydrocarbon and biomass for biodiesel production.