Simultaneous Microwave/Ultrasound-Assisted Hydrolysis of Starch-Based Industrial Waste into Reducing Sugars

Catalytic conversion of starch-based industrial waste into sugars was investigated using a simultaneous microwave/ultrasound-assisted procedure. The results were compared with single microwave and ultrasound irradiations to determine the eventual synergetic effects generated by the combined technologies. In heterogeneous systems, microwave irradiation enforces heat transfer, while ultrasound irradiation imposes the intensive mass transfer at the interfaces. Two hours of combined irradiation of potato starch (employed as a reference) at 60 degrees C in sulfuric acid revealed the existence of a glucose selectivity. In a result that was hitherto never achieved, 46% of this industrial waste was converted into reducing sugars in identical conditions.