Biocommodity engineering

The application of biotechnology to the production of commodity products (f uels, chemicals, and materials) offering benefits in terms of sustainable r esource supply and environmental quality is an emergent area of intellectua l endeavor and industrial practice with great promise. Such "biocommodity e ngineering" is distinct from biotechnology motivated by health care at mult iple levels, including economic driving forces, the importance of feedstock s and cost-motivated process engineering, and the scale of application. Pla nt biomass represents both the dominant foreseeable source of feedstocks fo r biotechnological processes as well as the only foreseeable sustainable so urce of organic fuels, chemicals, and materials. A variety of forms of biom ass, notably many cellulosic feedstocks, are potentially available at a lar ge scale and are cost-competitive with low-cost petroleum whether considere d on a mass or energy basis, and in terms of price defined on a purchase or net basis for both current and projected mature technology, and on a trans fer basis for mature technology. Thus the central, and we believe surmounta ble, impediment to more widespread application of biocommodity engineering Is the general absence of low-cost processing technology. Technological and research challenges associated with converting plant biomass into commodit y products are considered relative to overcoming the recalcitrance of cellu losic biomass (converting cellulosic biomass into reactive intermediates) a nd product diversification (converting reactive intermediates into useful p roducts). Advances are needed in pretreatment technology to make cellulosic materials accessible to enzymatic hydrolysis, with increased attention to the fundamental chemistry operative in pretreatment processes likely to acc elerate progress. Important biotechnological challenges related to the util ization of cellulosic biomass include developing cellulase enzymes and micr oorganisms to produce them, fermentation of xylose and other nonglucose sug ars, and "consolidated bioprocessing" in which cellulase production, cellul ose hydrolysis, and fermentation of soluble carbohydrates to desired produc ts occur in a single process step. With respect to product diversification, a distinction is made between replacement of a fossil resource-derived chem ical with a biomass-derived chemical of identical composition and substitut ion of a biomass-derived chemical with equivalent functional characteristic s but distinct composition. The substitution strategy involves larger trans ition issues but is seen as more promising in the long term. Metabolic engi neering pursuant to the production of biocommodity products requires host o rganisms with properties such as the ability to use low-cost substrates, hi gh product yield, competitive fitness, and robustness in industrial environ ments. In many cases, it is likely to be more successful to engineer a desi red pathway into an organism having useful industrial properties rather tha n trying to engineer such often multi-gene properties into host organisms t hat do not have them naturally. Identification of host organisms with usefu l industrial properties and development of genetic systems for these organi sms is a research challenge distinctive to biocommodity engineering. Chemic al catalysis and separations technologies have important roles to play in d ownstream processing of biocommodity products and involve a distinctive set of challenges relative to petrochemical processing. At its current nascent state of development, the definition and advancement of the biocommodity f ield can benefit from integration at multiple levels. These include technical issues associated with integrating unit operations with each other, integrating production of individual products into a multi -product biorefinery, and integrating biorefineries into the broader resour ce, economic, and environmental systems in which they function. We anticipa te that coproduction of multiple products, for example, production of fuels , chemicals, power, and/or feed, is likely to be essential for economic via bility. Lifecycle analysis is necessary to verify the sustainability and en vironmental quality benefits of a particular biocommodity product or proces s. We see biocommodity engineering as a legitimate focus for graduate study , which is responsive to an established personnel demand in an industry tha t is expected to grow in the future. Graduate study in biocommodity enginee ring is supported by a distinctive blend of intellectual elements, includin g biotechnology, process engineering, and resource and environmental system s.