CO2 Mitigation and Renewable Oil from Photosynthetic Microbes: A New Appraisal

The only major strategy now being seriously considered for biological mitigation of atmospheric CO^sub 2^ relies entirely on terrestrial plants. Photosynthetic microbes were the focus of similar consideration in the 1990s. However, two major government-sponsored research programs in Japan and the USA concluded that the requisite technology was not feasible, and those programs were terminated after investing US$117 million and US$25 million, respectively. We report here on the results of a privately funded US$20 million program that has engineered, built, and successfully operated a commercial-scale (2 ha), modular, production system for photosynthetic microbes. The production system couples photobioreactors with open ponds in a two-stage process - a combination that was suggested, but never attempted - and has operated continuously for several years to produce Haematococcus pluvialis. The annually averaged rate of achieved microbial oil production from H. pluvialis is equivalent to