Macroalgae, an abundant and carbon–neutral renewable resource, with several species rich in carbohydrates
are suitable for bioethanol production. This study focused on the pretreatment, enzyme saccharification
and fermentation of Sargassum spp., a brown macroalgae for bioethanol production. The optimal
acid pretreatment condition achieved in terms of glucose and reducing sugar yields was 3.4–4.6% (w/v)
H2SO4 concentration, 115 C and 1.50 h. The pretreated biomass was hydrolyzed with cellulase enzyme
system supplemented with b-glucosidase. After fermentation by Saccharomyces cerevisiae at 40 C, pH
of 4.5 for 48 h, the ethanol conversion rate of the enzyme hydrolysate reached 89%, which was markedly
higher than the theoretical yield of 51% based on glucose as substrate. Since all the glucose was consumed
during fermentation, other sugar sources might be present in the hydrolysate. The macroalgae, Sargassum
spp., showed significant potential as a renewable feedstock for the production of bioethanol.