Effect of hydrothermal pre-treatment on duckweed (Landoltia punctata) biomass for simultaneous saccharification and fermentation process

Duckweed has been proposed as a potential raw material to produce renewable biofuels, signified by: its high productivity and low competition with agriculture; its high proportion of carbohydrate (cellulose and starch); a low lignin content, which avoids the likely recalcitrance of cellulose to saccharification. This study has investigated the effect of hydrothermal pre-treatment on structural and chemical changes in Brazilian duckweed (L. punctata) biomass as well as its conversion to bioethanol, focusing on the hydrolysis and fermentation of the cellulose fraction. The biomass was hydrothermally pre-treated over a range of severities (1.9–4.8) and then subjected to simultaneous saccharification and fermentation. The best pre-treatment condition was at a severity factor of 3.9; this condition produced the highest ethanol yield (89 wt% of the theoretical potential yield). This represents a 63 wt% increase compared to untreated biomass. Hydrothermal pre-treatment has been shown to be a suitable technology for increasing ethanol yields from L. punctata biomass towards the theoretical maximum.