The reduction of oxygen-containing compounds, which is employed to produce biofuels from plant feedstock, requires a great amount of reductant that is commonly represented by molecular hydrogen obtained from non-renewable fossils.
For FS-based cellulosic ethanol production, enzyme use is a more significant factor than GS-based ethanol, because in the former case, converting the cellulosic feedstock requires a significantly higher enzyme dosage.
Insofar as regions differing in geography and climate favor the production of different feedstocks, and because different feedstocks require different pretreatments, a mature lignocellulosic ethanol industry may need to utilize a wide variety of pretreatment/feedstock combinations.
Due to different sugar composition, the two feedstocks require different optimal cell ratio.
The production of such highly functional molecules, whether derived from petroleum feedstocks, requires chemoselective transformations in which e.g. specific heteroatoms or functional groups are incorporated or removed without compromising the underpinning molecular properties.
While woody biomass exhibits a number of positive agronomic and logistical attributes, these feedstocks are significantly more recalcitrant to chemical pretreatments than herbaceous feedstocks, requiring higher chemical and energy inputs to achieve high sugar yields from enzymatic hydrolysis.
Feedstocks that do not require a substantial change in land-use include crop and municipal wastes, fall grass harvests, and algae [ 8].
In general agreement with Duncan McLeod at Shell, we determined that even in very large-scale production, hydrogen will never cost less than about $5.00/kg, and that will require a feedstock that costs less than about $1 per million BTU.
HTL represents a promising alternative to conventional lipid extraction methods as it does not require a dry feedstock or additional steps for lipid extraction.
Meeting EU targets for the consumption of transport fuels from bioenergy by 2020 will require a large increase in the production of bioenergy feedstock.
