The Challenge for Humanity: Renewable, Sustainable Sources of Bioenergy/Biofuels, Intermediate Chemicals, and Specialty Chemical Bioproducts

Humanity, as we know it, currently faces enormous political and scientific challenges in identifying and securing stable future sources of renewable energy in an environmentally acceptable and sustainable manner (i.e., leading to so-called biofuels/bioenergy). Similar concerns/considerations also apply to the continued future supply of other key petrochemical intermediates, such as monomers needed for industrial polymer production (e.g., polystyrenes and polyethylenes), as well as stable sources of key specialty chemicals (e.g., flavor and fragrance chemicals). This is, however, by no means a new scientific problem. It reflects instead one that has been difficult to solve over a period spanning more than three decades until now, and has been again brought to the forefront by the most recent biofuels/bioenergy crisis. Thus, there is an urgent need for highly creative and sound technological solutions for renewable (plant) resource utilization. To date, the difficulties in plant biomass utilization have centered on the recalcitrance of the various lignocellulosic matrices present in (woody) plants. This is largely, but not exclusively, due to the so-called lignin problem or challenge.

Regarding possible alternative sources of sustainable biofuels/bioenergy and various forms of bioproducts, it is generally recognized that truly novel (bio) technological solutions must be found and/or developed. Indeed, the U.S. Department of Energy was recently directed by the U.S. Congress to identify technology to produce 60 billion gallons of bioethanol annually by 2030, in order to replace some of the petroleum-derived gasoline. This, in turn, would require approximately 1.3 billion tons of lignified (woody) biomass annually in the United States alone, with the main plant species currently considered being corn, poplar, wheat, and more recently switchgrass (U.S. Department of Energy’s Genomics, 2006). The enormous scale of the proposed cultivation of plant biomass for biofuel/bioenergy emphasizes, by itself, the increasing need to identify at least one possible means of securing sustainable bioenergy/biofuel supplies over the long term. However, little detailed thought has apparently been given to the potential ramifications of utilizing large swaths of forestry, agricultural, or marginal land for this purpose, as well as the ethical and/or practical issues that may arise.

Such measures, however, address only the biofuels need. An additional challenge generally overlooked at present is the ability to produce sufficient levels of industrial polymers, such as polyethylenes, polystyrenes, and other products which historically have come from the petrochemical industry. Today, about 12% of all the petroleum resources are used for nonfuel/nonenergy purposes, including polymer and other specialty chemical applications. There is also the need to obtain stable supplies of key specialty chemicals, such as flavors and fragrances, which at present are produced in regions of varying political stability and can also be subject to seasonal (climatic) variations; such factors often result in unpredictable market prices for these commodities.