By: Rubina Obaid
Floating mats of Sargassum seaweed in the Great Atlantic Sargassum Belt represents the world’s largest macroalgal seaweed bloom. The Sargasso Sea is named after the discovery of this massive seaweed which is serving as the hotspot for biodiversity of our ecosystem. The two most abundant species are ‘fluitants’ and ‘natans’ which are found in the Sargasso Sea and notably connected by ocean currents. The Sargassum Belt stretches for 5,500 miles from the Gulf of Mexico to the western coast of Africa. These floating mats of seaweeds suffocate fragile seagrass habitats and coral reefs. The foul-smelling rotting seaweed also becoming the reason for the devastating tourism industry of Mexican and Carrabin beaches when washed to the shores.
Seaweeds are classified into three most renowned classes which include brown algae also known as Phaeophyta, green algae known as Chlorophyta, and red algae known as Rhodophyta. Whereas, Sargassum seaweed is the brown macroalgae that is found in the coastal areas, offshore platforms, and floating on seas. They are considered an important candidate for biomass for the production of biofuel due to cost competitiveness. The Hydrothermal Liquefaction process is administered with a catalyst to curtail retention time and operating temperature of the process, which increases the overall yield of bio-oil.
Allen is the part of the research team led by the universities Exeter and Bath studied, to scale up the environmental mess as various essential industrial commodities such as fertilizers, fuels, and chemicals. Allen says that “Converting marine biomass like seaweed usually requires removing it from salt water, washing it in freshwater and then drying it. That is very expensive so we needed to find a method that would be both economically and environmentally viable.” Thus, his team devised a separation process that provides an imperative step by creating a true salt-based marine bio refinery, by using acidic and alkaline catalysts to break down the salty seaweed. The remaining seaweed biomass becomes ready to be subjected to the HTL process and further split into different products. The sugar produced as a by-product in the process can be used to feed a yeast that produces a palm oil substitute. Liquid bio-oil which is obtained in the progression is then further processed into fuel and an aqueous, nutrient-rich fertilizer while heavy metals are recyclable and separated into a solid char.
The project lead at the University of Bath, Professor Chris Chuck explained that “The timings, sizes and exact locations of these seaweeds blooms are unpredictable, also its composition changes daily as it rots. So, a versatile technology is needed to cope with the heterogeneous nature of the material. Just as the crude oil industry creates liquid fuel, plastics, and fertilizers, we can benefit from similar flexibility. By altering the conditions to produce different amounts of specific by-products we can meet variable demand.” Scientists are developing alternative sustainable solutions through this golden opportunity across the Caribbean. Along with that a massive international effort is contributing to fixing the seaweed invasion in the most efficient manner to mitigate its negative impacts on tourism in Mexico.