Impact of steam explosion treatment on chemical configuration of Tall Fescue lignin : structural elucidation using NMR spectroscopy

In the economic and energy context of our society, it is universally recognized that alternatives to petrochemicals products must be found. To overcome this problem, renewable lignocellulosic
biomass could be used to produce high value products. To achieve this objective, pretreatment processes are required to allow the breakdown of lignocellulosic structure and increase accessibility
of the material. In this way, steam explosion is a thermo-mechano-chemical pretreatment which allows the opening of lignocellulosic material structural components and includes modifications of
the physical properties of the material, hydrolysis of hemicellulosic components and modification of the chemical structure of lignin [1].
This study is focused on the impact of various steam explosion treatments on the chemical configuration of tall fescue lignin. NMR analyses perform on the Festuca L. pretreated samples show
variations of links with treatment intensity. Observations show double phenomen :re-polymerization and depolymerization of the lignin structure during steam explosion process [2]. In parallel,
HPSEC analyses show modifications in the molecular weight of the lignin obtained after the steam explosion treatment.