Carbohydrate content in biomass is a suitable starting material to serve as a renewable feedstock for chemical products such as bio-degradable plastic and polylactic acid. Cassava starch is a common substrate for lactic acid production from fermentations, but rarely seen as a starting material in lactic acid production by a chemical method. This study shows that cassava starch is also a suitable starting material for a chemical process to produce lactic acid by the alkaline hydrothermal method assisted by microwave radiation. The effects of base catalysts, reaction temperature, catalyst concentration, and reaction time were investigated. In comparison with the lactic acid productivities obtained from cassava starch fermentations, the hydrothermal reaction method developed in this study gave higher volumetric productivities but lower lactic acid mass to cassava starch mass ratios. The advantages of the hydrothermal method also include the short operating time and low cost of the catalyst.
