Development of Botryococcus Seed Culture System for Future Mass Culture

The BOT-22 strain of Botryococcus braunii was cultured under laboratory and outdoor conditions. Medium K was developed, which decreased the cost of medium preparation to 1/30th. A polycarbonate bottle (10 L) was replaced with a polyethylene bag for cost effectiveness. Addition of nitrogen substantially increased biomass of the strain; however, the hydrocarbon content remained unchanged. Growth rates of >10 L scale cultures were much lower than those of <200 mL scale flask cultures. BOT-22 grew well in outdoor cultures despite extensive fluctuations in temperature and light conditions during the day from autumn to early winter and at spring. Maximum growth rates obtained using a tube bioreactor were two times higher than those obtained using 10L/30L scale cultures and a dome bioreactor. Thus, the tube bioreactor was more efficient for utilizing the light required for photosynthesis by this strain.