Conclusion

The extraction of hemicelluloses from wood upstream of cellulose production represents a very interesting opportunity to valorize different types of sugars in parallel with cellulose production for the paper industry. The studies presented here have shown that by varying the conditions of wood hydrolysis, and the wood species used, it is possible to vary the quantities and types of sugars extracted, as well as their nature (monomers or oligomers). It has also been shown that if the severity of hydrolysis is too high, a significant quantity of sugars can be lost as degradation products such as furfural and hydroxymethylfurfural, and that the optimum operating conditions need to be determined, depending on the intended applications. If the aim is to ferment sugars into alcohols, one solution is to subject the autohydrolysate to secondary hydrolysis, to transform all oligomers into monomers...