Biomass Valorization of Unexplored Canara and Capiaçu Elephant Grass Cultivars for Pyrolytic Sugar (Levoglucosan) Production via Fast Pyrolysis

This work aimed to evaluate the potential of two cultivars of elephant grass (Pennisetum purpureum Schum), canara and capiaçu, as feedstocks for energy purposes through levoglucosan production by fast pyrolysis. Levoglucosan is an anhydrous pyrolytic sugar that has great potential as a fermentation substrate for the obtaining of biofuels. Then, pyrolysis experiments were carried out seeking to intensify the levoglucosan production through the evaluation of the thermochemical conversion at 400, 500, and 600 °C, with biomass acid pretreatment (5, 10, and 15% v/v acetic acid) for canara and capiaçu biomasses, and 50% canara/capiaçu mixtures for co-pyrolysis. Structural as well as physicochemical composition changes after biomass acid treatment were observed prior pyrolysis. Statistical analysis revealed that pyrolysis temperature and biomass type significantly affected levoglucosan production at p < 0.1. Then, optimization by using the Design-Expert software pointed out that canara cultivar had the greatest potential since produced around fivefold more levoglucosan than untreated biomass and almost twofold more than capiaçu at 500 °C. However, co-pyrolysis seems to be a good alternative when biomass mixtures from different cultivars/varieties are available. Thus, the results from this study can be interesting to support lignocellulosic feedstock diversification to attaining pyrolytic compounds with special focus in anhydrosugars for renewable fuel production, adding value to the elephant grass productive chain.

Graphical Abstract