Salman's Infobahn

First-generation biofuels (produced primarily from food crops such as grains, sugar beet and oil seeds) are limited in their ability to achieve targets for oil-product substitution, climate change mitigation, and economic growth. Their sustainable production is under scanner, as is the possibility of creating undue competition for land and water used for food and fibre production. The cumulative impacts of these concerns have increased the interest in developing biofuels produced from non-food biomass. Feedstocks from ligno-cellulosic materials include cereal straw, bagasse, forest residues, and purpose-grown energy crops such as vegetative grasses and short rotation forests. These second-generation biofuels could avoid many of the concerns facing first-generation biofuels and potentially offer greater cost reduction potential in the longer term. The largest potential feedstock for ethanol is lignocellulosic biomass, which includes materials such as agricultura...

Image via Wikipedia The production of biofuels from lignocellulosic feedstocks can be achieved through two very different processing routes. They are: Biochemical – in which enzymes and other micro-organisms are used to convert cellulose and hemicellulose components of the feedstocks to sugars prior to their fermentation to produce ethanol; Thermo-chemical – where pyrolysis/gasification technologies produce a synthesis gas (CO + H 2 ) from which a wide range of long carbon chain biofuels, such as synthetic diesel or aviation fuel, can be reformed. Lignocellulosic biomass consists mainly of lignin and the polysaccharides cellulose and hemicellulose. Compared with the production of ethanol from first-generation feedstocks, the use of lignocellulosic biomass is more complicated because the polysaccharides are more stable and the pentose sugars are not readily fermentable by  Saccharomyces cerevisiae.  In order to convert lignocellulosic biomass to biofuels the ...