Vast caverns of CO2-absorbing bacterial fermentations producing high carbon-con­tent products with immediate human use — including bacterial cellulose as fiber, single-cell protein, or bioplastics — may be industrial realities for the later years of the present century but perhaps a more compressed timescale should occupy a high priority on the biofuels and climate change agenda. Over the coming 25 years, “hard

truths” about the global energy future will be (or are) unavoidable, and the role of biomass and other renewables in the emerging technological mix is a key issue.100

Any individual’s ranking of the immediate challenges that could be met by biotechnology is biased and partial but a useful departure point may be the prior­ity list of discussion items in a major international conference on biofuels held in 2007.