cofunded by industry and DOE that includes research in biotechnology (AFPA, 1994).
Through genetic engineering, new genes, and thus new biochemical pathways, can be transferred into plants enabling the creation of novel coproducts in bioenergy crops. The bioenergy crops of the future may be the feedstock for biorefineries for which energy is only one, perhaps the least valuable, of several products. Coproducts under commercial development via the genetic engineering of plants include vaccines and other high-value pharmaceuticals, industrial and specialty enzymes, and novel fragrances, oils, and plastics. Bioenergy crops might logically be engineered to produce high quantities of cellulytic enzymes, such as cellulase or xylanase, which could be used directly for feedstock processing and thus reduce the cost of cellulase required for production. For other feedstocks, such as corn stover and switchgrass, genes and genetic engineering methods will be available from major biotechnology companies as a result of their work on maize and rice. For poplars, the genes developed for dicot crops can often be directly tested or adapted.
Modifications of feedstock biomass are a highly desirable way to facilitate processing; however, the necessary modifications will vary with the energy product and processes. For example, higher lignin quantity is likely to be desirable for combustion to produce electricity because of its high energy density compared to polymerized sugars. For fermentation to ethanol, however, lignin could be reduced or modified so that it can be removed at less expense and with less interference for processing enzymes and microorganisms. Hemicellulose structure also appears to be important for processes that use enzymatic digestion. Feedstock, therefore, will have to be engineered differently for different products, pretreatments, and processing methods. A number of genes are already known that could be tested in transgenic plants for their effects on feedstock processing into ethanol. Many more possibilities for quality engineering will become available as catalogs of genes expressed in lignocellulosic tissues are uncovered by genomics studies (Sterky et al., 1998). To understand how feedstock should be engineered for different products, pretreatments, and processing methods, the research programs of OFD's processing and feedstock development groups should be integrated.
Investigations in genetic engineering and genomics of biomass feedstocks could be integrated to avoid duplication of effort via the establishment of virtual centers that would include DOE and other government laboratories, universities, the private sector, and international partners. These virtual centers would be designed to share complementary tasks across several facilities that have the technologies in hand. Some functions that are national in scope may be more effective if they are centralized, but others will be more effective if they are regionalized to take into account study materials created by local breeding programs and genetic traits expressed in specific environments. Studies should be carefully prioritized and monitored by DOE with the aid of a national review panel to ensure that project proposals do not overlap but contribute to the goals of the investigations of the virtual center. Apart from tool development, these investigations should be directed toward target traits that have been selected for their scientific, technological, and economic values, and consider environmental acceptability as well as production goals.
Given the resources available to the Office of Fuels Development, the feedstock program funds have been well allocated, and research programs have clarified production and environmental issues.
The feedstock program is appropriately involved in extramural projects with investigators from universities, industry, and other government agencies.
Given the importance of the cost of dedicated feedstock to the economics of bioenergy production and the potential for technological advances via breeding and biotechnology, research on feedstock development may be inadequately funded to achieve substantial reductions in the cost of feedstock even in the long run.
A more formal process for the selection and review of feedstock projects and outside participants should be established and the use of peer reviews expanded, especially if there are significant increases in program funding.
Because of the many opportunities for genetic improvements in the midterm, the Office of Fuels Development should seriously consider expanding its applied biotechnology and genomics programs to improve feedstock yields, pest resistance, quality, and cropping systems. Although the Office of Fuels Development is well suited to take the lead in these programs, the agency should work in coordination with other government agencies (e.g., U.S. Department of Agriculture and the National Science Foundation) and grant programs, international partners, and the forest, agricultural, and biotechnology industries.
Investigations in genetic engineering and the genomics of biomass feedstocks should be integrated to avoid duplication of effort.