Development of a Simultaneous Saccharification and Fermentation Technology for Valorisation of Ulva spp. from Macroalgal Blooms

Uncontrolled macroalgal blooms, also known as green or golden tides, is an increasingly frequent global phenomenon and is partly attributed to the increased eutrophication of the marine environment caused by anthropomorphic industrial and agricultural activities.

The green opportunistic macroalgae genus Ulva thrives in such conditions and accounts for more than half of global blooms.

Various environmental and economic problems have been associated with the occurrence of such blooms; however, if utilised appropriately, the biomass generated from these tides has the potential to be economically rewarding.

Ulva spp. have an interesting chemical composition that is predominated by carbohydrates (≤65% dry weight), followed by proteins and lipids.

Ulvan, a sulphated polysaccharide consisting of rhamnose, glucuronic acid, iduronic acid and xylose, is the predominant molecule, followed by cellulose.

Contemporary research has focused on exploiting the cellulose fraction only, with ulvan, consisting of unique monosaccharides, being overlooked due to the unavailability of suitable saccharification enzymes.

Although work on the saccharification of ulvan is gaining momentum, the complete enzymatic breakdown is still a bottleneck.

Similarly, the unique monosaccharide composition of ulvan has not been explored to its full potential for fermentation to value-added products.

This project, therefore, aims to develop a suitable technology to saccharify both ulvan and cellulose from the biomass and ferment all the monosaccharides present in the hydrolysate to value-added products.

Novel and commercial enzymes would be identified and trialled in individual processes for saccharification and fermentation first; with a simultaneous process subsequently optimised to minimise resource inputs and generate minimum waste streams.

The developed process would finally be evaluated at a pilot scale to demonstrate its potential to be implemented at the industrial level.