Abstract
Algal biomass, called blue carbon, is attracting attention as biomass that is capable of fixing CO2 rapidly. Fast-growing green algae such as Ulva meridionalis are expected to be used for CO2 fixation and for bioremediation of eutrophic sea areas. U. meridionalis rapidly assimilates CO2 as a sulfated polysaccharide called "ulvan". Microwave-assisted extraction processes can achieve efficient extraction of ulvan. Furthermore, ulvan can be efficiently converted to monosaccharides by using microwave heating and polyoxometalates as an environmentally benign superacid catalyst. The sulfated structure of ulvan was effective both for collection of microwave energy and for efficient extraction and conversion of ulvan by microwaves. Rapid CO2 fixation by U. meridionalis and effective utilization of ulvan by microwaves represents a new carbon-neutral chemical process based on algal biomass.
