Production of sugars from macro-algae Gracilaria verrucosa using combined process of citric acid-catalyzed pretreatment and enzymatic hydrolysis

In this study, a combined process of citric acid-catalyzed pretreatment and enzymatic hydrolysis was applied for production of total reducing sugar (TRS) from marine macro red-algae Gracilaria verrucosa as a potential resource. By citric acid-catalyzed pretreatment under the 1:10 solid-to-liquid ratio, 0.1 M citric acid, 150 °C, 60 min condition, a 50.9% TRS yield was obtained. By subsequent enzymatic hydrolysis using enzyme mixture (20 FBG/g-biomass and 28 FPU/g-biomass), a 57.8% TRS yield was obtained. Because citric acid-catalyzed pretreatment is simple, cheap, and environmentally friendly (do not use hazardous chemicals), these results served to demonstrate the significant potential of citric acid-catalyzed pretreatment to produce TRS for biofuels and biochemicals refinement purposes.