Biorenewables, the bio-based economy and sustainability.

This issue of Interface Focus is being used to introduce readers of Interface to research into the use of plants to supply mankind with renewable energy and material resources. This field is given the general name of biorenewables research, but over the past few years it has come to public attention through media coverage surrounding one type of biorenewable product, liquid biofuels. Biofuels research lies at a complex set of interfaces, where the worlds of research and innovation meet those of business and politics. This is a difficult arena in which to work at the best of times, but when the world is urgently seeking to develop truly sustainable energy resources to combat climate change, the quality of scientific advice will be at a premium. Mankind can ill afford to make mistakes in the technologies it pursues to reduce greenhouse gas emissions. Because crops use photosynthesis to convert atmospheric CO 2 into the organic compounds that are used to generate biofuels, it appears that biofuels should be able to eliminate anthropogenic CO 2 emission from internal combustion engines. This simple idea has been at the heart of the arguments in favour of exploiting plant biomass for liquid fuel. Of course this picture is an oversimplification, since the complete process of generating the fuel is, in general, not free of greenhouse gas emissions. The promise of biofuels as a climate change mitigation technology, therefore, rests upon the technology's ability to maintain very low levels of greenhouse gas emissions in its production. Brazil has over 35 years of experience from its development of the science, technology and economics of sugar cane bioethanol production. Here, it is widely accepted that the process life cycle of the biofuel results in a sizeable reduction in greenhouse gas emissions with respect to petroleum fuel. In large part, the success of sugar cane ethanol rests on the productivity of the cane and the simplicity of the processing. Other sugar crops and starch crops can and have been used for alcohol-based fuels in other parts of the world, oil-bearing crops have been used to make biodiesel and scientists and technologists are now looking at ways to convert woody material into alcohols. (These technologies are described in two of the papers, i.e. Landeweerd et al. [1] and van Zyl et al. [2]) Some, but not all, of these fuels are calculated to produce lower greenhouse gas emissions than their …