IV. A.2.a. General Considerations

The conclusions presented elsewhere in this report focus attention on the fundamental issue of how to maximize the overall productivities of microalgae systems and suggest that there still is considerable scope for improvements. The issue of productivity, in its various guises and aspects, from species control to lipid (oil) yield and harvesting, is therefore recommended as a central subject for any future U. S. R&D program in microalgae biodiesel production. Essentially, the focus would be on developing the microbial catalysts that can convert solar energy to a liquid fuel at high overall efficiency. This effort will require a relatively long-term R&D effort, which would, at least initially, be focused on the fundamental and early-stage applied research required for such a biocatalyst development effort.

This recommendation implies that engineering design, cost and resource analyses, and even outdoor pond operations, discussed in Section III, would be relatively minor parts of such a projected R&D program, at least initially. The argument is that most of the variables of large-scale microalgal culture can be scaled-down to very small-scale, even laboratory systems. This allows detailed investigation of the key parameters in maximizing productivities. At present the central issues in scale-up are those of algal species dominance and grazer control (and other biological invasions). However, at this point these are secondary to the necessity and priority of establishing a high benchmark for productivity and lipid induction, under physicochemical and other environmental conditions that would allow extrapolation to large-scale outdoor systems at typical locations.

Again, this will require a relatively long-term R&D effort to accomplish, although guideposts, such as efficiency goals, to the needed advances can be provided. One issue is how to select strains for genetic improvements. This is still a difficult choice, as a relatively large investment is required to develop any novel genetic system. On the other hand, selection of the best strains for such a targeted genetics development effort is still some time off. Thus, a parallel track is recommended: strain selection (screening and improvements) would be carried out alongside with genetic engineering studies to demonstrate productivity enhancements using microalgal strains with already well-developed genetic systems. Such improvements would be in the efficiency of photosynthesis, described next, and lipid productivities, extending the ASP research reviewed in Section II.