Abstract

As an alternative to the use of edible crops as raw materials or the use of lignocellulosic materials for production of the second-generation biofuels, macroalgae biomass has potential as a sugar resource for the production of third-generation biofuels. As higher amounts of biomass are required for this endeavor, commercial cultivation of brown algae is necessary to avoid overexploitation of natural populations. The macroalgae species contain different kinds of polysaccharides and pretreatment is necessary to make them available using different strategies. The most abundant sugars in brown algae are alginate, mannitol, and glucan; whereby the degradation of these polysaccharides requires specific enzymes for the release of monosaccharides. Monosaccharides are most efficiently fermented into ethanol by engineered microorganisms, but as recently demonstrated, both Saccharomyces cerevisiae and Escherichia coli strains have this capability also. Saccharification and fermentation steps can be carried out in different configurations. This chapter presents a review of each step of the process for bioethanol production from brown algae.