New pretreatment of wheat straw and bran in hexadecanol for the combined production of emulsifying base, glucose and lignin material

Wheat straw and bran are abundant residues of agriculture which are increasingly being considered as a feedstock for the production of fuels, energy and chemicals. The acidic hexadecanol based pretreatment of wheat straw and bran was investigated in this work. This pretreatment allowed the conversion in one step of hemicelluloses of wheat bran and straw into hexadecyl pentosides with yields up to 95%. Wheat-based surfactants thus obtained exhibited superior emulsifying properties compared to fossil-based polyethoxylated fatty alcohols that are largely used surfactants in cosmetics and pharmaceutics industries. The non-converted materials collected after the pre-treatment were characterized showing that cellulose, starch and lignin remain available for further processing. Enzymatic digestibility of the remaining cellulose contained in the hexadecanol pretreated straw was evaluated showing a glucose production of up to 63% compared to the 13% obtained with a non pretreated wheat straw. This result is of potential interest for ethanol fermentation. A lignin material was produced from the same hexadecanol pretreated straw residue. This material displayed a higher molecular weight than a lignin material obtained following an organosolv process, confirming its potential use in the field of thermosetting resin. In view of the growing importance of renewable resource-based molecules in the chemical industry, this approach may open a new avenue for the conversion of wheat straw and bran into various chemicals. (c) 2012 Elsevier Ltd. All rights reserved.