Professor WATANABE Makoto, Faculty of Life and Environmental Sciences

Botryococcus braunii (referred to hereafter as "Botryococcus") is a type of green algae which lives in fresh and brackish waters (comprised of a mixture of fresh and sea water). The individual cells, with a diameter 10-20 μm, gather together and form colonies 30-500 μm in size.

The oil produced by many types of algae is triglyceride (a vegetable oil) and it accumulates inside cells. However, the oil produced byBotryococcus is a hydrocarbon (petroleum-based oil). The hydrocarbon synthesized in the cell is secreted to the outside of the cell, and accumulated in colonies. If aBotryococcus sample is placed on a glass slide, and squished down with the cover glass, the hydrocarbon which has been secreted by the cells and accumulated in the colony bleeds out from the cells and can be seen.

The distinguishing features of theBotryococcus cultivated at the University of Tsukuba are a good balance of growth and oil production, and good reproduction in alkaline environments into which CO2 can easily dissolve. Also, growth ofBotryococcus is promoted to a striking degree if organic waste water (from households or industry etc.) is provided at an appropriate concentration. High biomass production (note 1) is obtained even under weak light. At the current stage, it is estimated that roughly 10 tons of oil can be produced per hectare per year, but if it becomes possible to produce 10 times that amount of oil per hectare, it should be possible to supply the oil at almost the same price as petroleum today, and that may enable practical use.

At present, we are conducting technology development with the aim of increasing oil production efficiency by one order of magnitude, based on a Strategic Basic Research Program overseen by the Japan Science and Technology Agency (JST). In addition, using a special grant from the Ministry of Education, Culture, Sports, Science and Technology for the Core Laboratory of Algal Biomass Energy System, we are promoting international collaboration, and collaboration between industry, academia, and independent administrative agencies, with the aim of creating an international base for development of algae energy technology at the University of Tsukuba.

(Right photo) Microscopic image of Botryococcus
(Left photo) Culturing Botryococcus

(Note 1) The term "biomass" refers to renewable organic resources produced from animals and plants, such as livestock wastes, kitchen wastes, and wood scraps. (From the text of "Biomass Nippon," Ministry of Agriculture, Forestry and Fisheries)