Wrapping the world with Seaweed: the next plastic
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Introduction
Plastic pollution has been one of the most urgent environmental issues in the 21st century. As over 460 million metric tons of plastic are produced every year, with a portion of it degrading into microplastics, which are plastic particles smaller than 5mm, these particles were found to accumulate in animals, plants and even human bodies (IUCN, 2024). Microplastics pose risks to ecosystems and towards human health due to its ability to absorb toxic chemicals and enter the food chain (Rafa et al., 2024). Studies had also found out that microplastics from inhalation and dietary use had increased six times from the year 1990 to 2018 (Zhao & You, 2024).
While groundbreaking discoveries like plastic-degrading bacteria help address existing waste, the world desperately needs to reduce and stop the production of plastics. To achieve a true circular economy, researchers are turning to one of the ocean's most abundant resources, seaweed.
The Power of Macroalgae
Bioplastics derived from corn starch or sugarcane require vast amounts of arable land and freshwater. This puts them in direct competition with global food supplies and natural terrestrial ecosystems Yadav & Ganesh Chandrakant Nikalje, 2024). Seaweed, however, circumvents these issues as Macroalgae have high growth rates, causing it to produce higher yield of biomass and generate substantial biomass without requiring fresh water or terrestrial farming space (Liu et al., 2023).
Furthermore, seaweed acts as a potent carbon sink. By absorbing dissolved inorganic carbon dioxide during photosynthesis, seaweed farming mitigates both climate change and ocean acidification. Its unique biochemical composition, notably its negligible low lignin content, making it highly energy-efficient to break down and doesn’t require delignification processes (Baghel et al., 2021).
Mechanisms and Extraction
The secret to seaweed's potential lies in its structural polysaccharides. The three primary polymers extracted for bioplastic production are as shown in this table below:
Polymer | Species Source | Extraction Method | Properties |
Alginate | Brown seaweed (Phaeophyceae) | Acid wash and precipitation (calcium salt/alginic acid) | Film-forming and entrapment and immobilization abilities |
Carrageenan | Red seaweed (Rhodophyta) | Alkaline Treatment | Barrier against moisture loss and oxidation |
Agar | Red seaweed (Rhodophyta) | Agarose and agaropectin extraction | Strong gelling and thickening agent, antimicrobial, antioxidant |
(TECHNICAL RESOURCE PAPERS REGIONAL WORKSHOP on the CULTURE and UTILIZATION of SEAWEEDS VOLUME II, 2025)
Challenges and Limitations
Despite its immense potential, several obstacles currently hinder the large-scale
commercialization of seaweed bioplastics:
High Hydrophilicity: Bioplastics derived from seaweed (especially alginate) are highly hydrophilic, meaning they have the ability to absorb massive amounts of water. Which compromise their structural integrity in wet environments.
Batch Variability: The chemical composition of seaweed varies on the species, the season of harvest, and the marine environment, making industrial standardization needing to find a potential species suitable for quality standardisation.
Future Porespects
Recent advances in extraction technologies such as microwave assisted extraction are improving polymer yields while drastically minimizing energy consumption (Gonzaga et al., 2025).
Transitioning from petroleum based plastics to marine derived biopolymers represents a monumental shift in materials science. By harnessing the rapid growth and unique biochemical properties of macroalgae, we can tackle the systemic issue of plastic pollution at its root. While optimization in manufacturing and standardization is still required, the marriage of marine biology and sustainable engineering promises a greener, cleaner future.
Citation
Baghel, R. S., Reddy, C. R. K., & Singh, R. P. (2021). Seaweed-based cellulose: Applications, and future perspectives. Carbohydrate
Polymers, 267, 118241. https://doi.org/10.1016/j.carbpol.2021.118241
IUCN. (2024, May). Plastic Pollution. Iucn.org. https://iucn.org/resources/issues-brief/plastic-pollution
Liu, J., Zhou, F., Abed, A. M., Le, B. N., Dai, L., Elhosiny Ali, H., Khadimallah, M. A., & Zhang, G. (2023). Macroalgae as a potential
source of biomass for generation of biofuel: Artificial intelligence, challenges, and future insights towards a sustainable environment. Fuel,
336, 126826. https://doi.org/10.1016/j.fuel.2022.126826
Rafa, N., Ahmed, B., Zohora, F., Bakya, J., Ahmed, S., Ahmed, S. F., Mofijur, M., Chowdhury, A. A., & Almomani, F. (2024). Microplastics
as carriers of toxic pollutants: Source, transport, and toxicological effects. Environmental Pollution, 343, 123190.
Gonzaga, L. J., Pérez Roa, M. E., Lavecchia, R., & Zuorro, A. (2025). Unlocking marine potential: Microwave-assisted extraction of
bioactive compounds from marine macroalgae. Journal of Environmental Chemical Engineering, 13(3), 116858.
TECHNICAL RESOURCE PAPERS REGIONAL WORKSHOP ON THE CULTURE AND UTILIZATION OF SEAWEEDS VOLUME II.
Yadav, K., & Ganesh Chandrakant Nikalje. (2024). Comprehensive analysis of bioplastics: life cycle assessment, waste management,
biodiversity impact, and sustainable mitigation strategies. PeerJ, 12, e18013–e18013. https://doi.org/10.7717/peerj.18013
Zhao, X., & You, F. (2024). Microplastic Human Dietary Uptake from 1990 to 2018 Grew across 109 Major Developing and Industrialized
Countries but Can Be Halved by Plastic Debris Removal. Environmental Science & Technology, 58(20).
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