Pretreatment of biomass.

http://dx.doi.org/10.1016/j.biortech.2015.10.092 0960-8524/ 2015 Published by Elsevier Ltd. The Biorefinery concept is recognized as one important strategy the world can use to wean itself off finite hydrocarbons, using renewable biomass feedstocks to establish a more sustainable global society. The world’s most abundant natural material is cellulose which, like starch, is composed of glucose. However, unlike sugar or starch which nature designed more as a readily biodegradable biomass source and which has been used as the initial feedstock of many pioneering biorefineries, cellulose is a structural material that is much more difficult to deconstruct. This is a result of both its intrinsic, close polymeric alignment and its intimate association with other lignocellulosic components such as hemicellulose and lignin. Although significant advances have been made in enhancing the enzymes that can hydrolyze cellulose, some form of pretreatment is invariably required, to both facilitate the recovery of the associated lignin and hemicellulose components in a higher value form and to enhance accessibility of the enzymes to the cellulose. As indicated in this special issue there are a wide range of lignocellulosic/biomass materials that can act as the feedstock for a biorefinery. Thus, the type of pretreatment required to fractionate and enhance component recovery and cellulose accessibility will be strongly influenced by the nature of the substrate. These include highly recalcitrant, softwood lignocellulosic materials to the likely more malleable micro/macro algae that have been suggested as possible future feedstocks. As well as a biorefinery approach a parallel, thermorefinery strategy has also been suggested as a possible means of converting biomass to useful products and this topic has also been covered in this special issue. The most current biomass pretreatment R&D activities in the bio and thermorefinery areas have been profiled in this special issue with the hope with particular emphasis on technology developments, industrialization and commercialization of biofuels and the overall bioand thermo-refinery processes. This special issue contains 53 selected, peer reviewed papers classified into the four themes of; (1) pretreatment of lignocellulosic materials, (2) pretreatment of algal biomass, (3) pretreatment as it relates to a thermorefinery approach and, (4) others.