Brown algae hydrolysis in 1-n-butyl-3-methylimidazolium chloride with mineral acid catalyst system

► Sugars were successfully recovered from three brown algae species. ► Hydrolysis was most efficient in ionic liquid [BMIM]Cl with HCl as acid catalyst. ► Acid loading, time and temperature were critical for high TRS yield and selectivity. ► Biomass characterization supports the efficiency of hydrolysis in [BMIM]Cl/HCl.