From first- to third-generation biofuels: Challenges of producing a commodity from a biomass of increasing complexity

Biofuels, in conjunction to their positive carbon balance with regards to fossil fuels, also represent a significant potential for sustainability and economic growth of industrialized countries because they can be generated from locally available renewable material. Biofuels are usually classified as follows: 1. First-generation biofuels are directly related to a biomass that is generally edible. 2. Second-generation biofuels are defined as fuels produced from a wide array of different feedstock, ranging from lignocellulosic feedstocks to municipal solid wastes. 3. Third-generation biofuels are, at this point, related to algal biomass but could to a certain extent be linked to utilization of CO2 as feedstock. Scaling second and third-generation biofuel processes thus requires solid economics that are directly dependent on optimized carbon utilization that relies on the production of fuels (commodities), as well as high value co-products.