Fermentation of C6 carbohydrates from triticale straw hemicellulosic fraction as pretreatment for xylose purification

Triticale (Triticosecale Wittmack), may be considered as an energy crop because of its fast growth rate, of its potential for human and animal feed but as well, for its lignocellulosic content. Such potential, combined to the fact that it can grow in northern climate has raised significant interest for this plant in Canada. In this work, the non-edible part of the plant (straws) of triticale (Triticosecale Wittmack 'Pronghorn') was fractionated using the Feedstock Impregnation Rapid and Sequential Steam Treatment (FIRSST). Fractionation was performed using both a one and a two-step steam process leading to the isolation of the different macromolecular fractions from lignocellulose. Results showed that in addition to its potential for ethanol production, the two-step FIRSST treatments have shown promising results producing a high quality pulp (selectivity of 94% into alpha-cellulose) whilst allowing direct recovery of solubilized hemicelluloses. After isolation, the C6 carbohydrates from the hemicellulosic fractions were fermented to ethanol after being first hydrolyzed using a non-enzymatic approach. The hydrolyzed hemicellulosic broths were then fermented using Saccharomyces cerevisiae and results showed a high C6 sugar conversion with 96.8 wt% of the glucose converted to ethanol thus producing a mixture of relatively pure xylose. (C) 2013 Elsevier B.V. All rights reserved.