Microwave-assisted hydrothermal extraction of sulfated polysaccharides from Ulva spp. and Monostroma latissimum

Microwave-assisted hydrothermal extraction was applied for production of sulfated polysaccharides from Ulva spp. and Monostroma latissimum. The maximum ulvan yields attained 40.4 ± 3.2% (Ulva meridionalis) and 36.5 ± 3.1% (Ulva ohnoi) within 4 min of come-up time and 10 min of extraction time at 160 °C, respectively. The rhamnan sulfate yield from M. latissimum further attained 53.1 ± 7.2% at 140 °C. The sulfated polysaccharides were easily recovered from the extract by simple ethanol precipitation. In addition, molecular weights and viscosity of the extracted polysaccharides could be controlled by varying the extraction temperature. Dielectric measurement revealed that ionic conduction was the important parameter that affect the microwave susceptibility of algae-water mixture. The sulfated polysaccharides extracts are expected as potential feedstock for medical and food applications.