Sugar Production for bioethanol from alfalfa stems. Results, and comparative study with application of lignocellulolytic activities of novel fungal species.

Bioethanol production from non-food lignocellulosic material is one of the most important topics in the field of biofuel production. We report on experiments with a treatment for the production of fermentable sugars from the fibrous parts of alfalfa (Medicago sativa L.), a widely used forage plant. Our study regards a process divided into the following steps: fungi treatment, microwave hydrolysis and enzymatic hydrolysis with a mixture of cellulase and β−glucosidase leading to the final production of fermentable sugars. This process was followed by a detailed HPLC analysis for the detection of sugars, oligomers but also by-products (furfural, hydroxymethylfurfural and acids) that could affect fermentation. Scanning electron microscopy (SEM) was used for a visual characterization of the material throughout all these steps, and TGA to quantify cellulose and lignin content. Fungi treatment improves the production of fermentable sugar yield obtained from hydrolysis. This could be related to the removal of lignin and thus a major exposure of cellulose fibers. In fact the degradation activity of these cultures on lignin was already documented on poplar wood (Doria et al., 2014).