Assessment of macroalgal biomass potential in Tunisia for bioethanol production

Abstract The valorization of marine macroalgal biomass is among the most promising international programs focusing on the sustainable exploitation of marine environment. However, macro-algal biomass remains unexploited in Tunisia even though it represents a renewable and highly abundant biomass. This causes several environmental disorders due to the excessive proliferation of several algal species. The objective of this work is to study the potential use of macroalgae as biofuels feedstock in the Mediterranean region and particularly in Tunisia. This study focuses on certain macroalgal species collected from Bizerte and Tunis lagoons. It reports the biochemical characterization of the studied macroalgae in order to determine their possible valorization areas and demonstrate their richness in high value molecules. In fact, our experiments show that the maximum protein content of 16.22%±0.270 was obtained with G. verrucosa and the maximum carbohydrates content of 58.46%±1.52 was obtained with Dictyopteris polypodoies. This leads us to believe that macroalgae constitute a potential source of fiber and proteins. After a sulfuric acid pretreatment, the macroalgae’s solid fractions were hydrolyzed using cellic Ctec2 enzymatic extract leading to a maximum reducing sugars yield of 324.6 mg/gDM. Monomeric sugars from the studied macroalgae hydrolyzates were fermented, leading to maximum ethanol yield of 0.24g/gDM.