Lignocellulosic biomass processing: a perspective.

As biorefineries replace oil refineries, society and the environment will benefit from a switch from hydrocarbon feedstocks to renewable carbohydrates as a source of energy, materials and chemicals. Biomass-based ethanol technologies are rapidly evolving and bottlenecks are being identified that need to be overcome to achieve widespread commercialization. Current research is driven by the need to reduce the cost of biomass-ethanol production. The preferred method is to thermochemically pretreat the biomass material and subsequently, enzymatically hydrolyze the pretreated material to fermentable sugars that can then be converted to ethanol. Pretreatment research is focused on developing processes that would result in reduced bioconversion time, lower cellulase enzyme usage, and/or higher ethanol yields. Cellulase research efforts are focused on develop ing a cost-effective, highly thermostable, synergistically acting enzyme mixture that would meet the end user's needs. Robust fermentation microorganisms are also being developed for conversion of biomass sugars to ethanol and other bioproducts. An integrated research and development approach is paying off and commercial plants for the production of biomass-ethanol are close to becoming a reality.