Reproductive sterility increases the capacity to exploit the green seaweed Ulva rigida for commercial applications

Abstract

Periodic biomass losses caused by reproduction have greatly limited the expansion of the land-based cultivation of the seaweed Ulva. In an attempt to resolve this, we obtained a sterile mutant (SM) of U. rigida by mutating a wild type (WT) strain using ultraviolet radiation (UVC). The SM grew five times faster than the WT with 40.0% and 30.9% higher nitrate and phosphate uptake rates. Crucially, the SM remained in the vegetative state throughout the 27-day trial, unlike the WT. The lipid content was more than double that of the WT with more monounsaturated, polyunsaturated, omega-3 and omega-6 fatty acids but with a 26.3% lower protein content. The swelling, water holding, and oil holding capacities were all lower than the WT. The rapidly growing SM showed distinct promise for application to carbon capture and wastewater bioremediation and for more conventional aquaculture practices. Despite some modified nutritional and functional properties, the SM still retained a desirable nutritional profile.