Green ultrasound-assisted extraction of pigments from Mexican Caribbean Sargassum

## Our Take: A Greener Path to Unlocking Sargassum's Potential

The burgeoning Sargassum blooms plaguing the Caribbean are increasingly recognized as a dual challenge: an environmental hazard and a potential resource. While the sheer volume of *Sargassum fluitans* and *S. natans* washing ashore creates significant economic and ecological burdens, these brown macroalgae harbor a wealth of valuable compounds, particularly pigments with promising bioactive properties. Traditionally, extracting these pigments – notably fucoxanthin, chlorophyll, and carotenoids – has relied on harsh, toxic organic solvents, presenting a sustainability paradox. This new research, detailing the use of ultrasound-assisted extraction (UAE) with hydroethanolic mixtures, offers a compelling solution, aligning with the growing imperative for environmentally responsible resource utilization. The work builds on previous efforts to sustainably manage Sargassum, such as those exploring its use as biofuel feedstock Sargassum Biofuel Potential and its role in coastal protection Sargassum Coastal Defense. The demonstrated viability of a greener extraction process is a significant step towards unlocking the economic potential of this abundant biomass while mitigating its negative impacts.

The study's focus on optimizing extraction parameters – ethanol concentration, temperature, and solid-to-liquid ratio – highlights the rigorous scientific approach necessary to translate a promising concept into a practical application. While the reported pigment yields are slightly lower than those achieved with traditional solvent methods, the trade-off in reduced toxicity and improved consistency is a considerable advantage. The authors rightly emphasize the importance of rapid analytical methods for efficient pigment quantification, which is crucial for real-time process monitoring and quality control. The development and validation of these streamlined analytical techniques—using UHPLC and microplate-based spectrophotometry—reduces both time and sample consumption, making the entire process more accessible and scalable. This is particularly important for regions with limited laboratory infrastructure, where implementing sustainable biorefining processes can be challenging. The research also underscores the need for a holistic, integrated approach, recognizing that efficient pigment extraction is just one component of a complete Sargassum valorization strategy – a concept we have previously discussed in relation to marine biorefineries and circular economy models Marine Biorefineries.

Beyond the immediate implications for pigment extraction, this study reinforces the broader trend towards bio-based solutions and sustainable processing technologies within the marine sector. The principles demonstrated – utilizing renewable solvents, optimizing extraction conditions, and developing efficient analytical methods – are applicable to a range of marine biomasses and bioactive compounds. This research actively contributes to the burgeoning field of “blue biotechnology,” which seeks to harness marine resources for innovative products and solutions. The adoption of UAE technology, in particular, is gaining traction across various industries due to its energy efficiency and ability to enhance extraction yields while minimizing environmental impact. The observed secondary effects of temperature and solid-to-liquid ratio further emphasize the need for careful calibration and process optimization to maximize efficiency and minimize waste, aligning with principles of precision extraction.

Looking ahead, the successful implementation of this hydroethanolic UAE approach will depend on scaling up the process to industrial levels and conducting further economic analyses to assess its competitiveness. A key question remains: how can these localized extraction efforts be integrated into larger-scale Sargassum management strategies, ensuring both environmental sustainability and economic viability for coastal communities? Further research should focus on exploring the potential for utilizing the residual biomass after pigment extraction, potentially as a source of other valuable compounds or as a feedstock for bioenergy production, truly realizing a circular economy model for this abundant, yet problematic, marine resource.