Beneath the vast, rolling waves of our oceans lies a group of unassuming yet remarkably valuable organisms—brown algae. Anchored to intertidal zones or thriving in deep-sea habitats, these algae endure the rigors of the marine environment, accumulating a wealth of nutritional compounds in the process. Among the brown algae family, four species stand out:Ascophyllum nodosum(knotted wrack),Ecklonia maxima(giant kelp),Lessonia trabeculata(LF), andLessonia nigrescens(LN). Hailing from diverse marine regions—including the North Atlantic coasts, the shores of South Africa and Chile, and the Pacific coasts of South America—each boasts unique growth traits and compositional strengths.
In recent years, as humanity’s exploration of marine resources deepens, the nutritional value and application potential of these four brown algae species have gradually come to the forefront. Through systematic compositional analysis and evaluation, researchers have unlocked the nutritional secrets hidden within these algae, laying a scientific foundation for their use across multiple industries. In agriculture, these “nutritional treasure troves” from the sea are emerging as powerful assets, poised to drive the green development of global farming practices.
Portraits of Brown Algae Species
Ascophyllum nodosumbelongs to the family Fucaceae, order Fucales, class Cyclosporeae, and phylum Phaeophyta. Characterized by its brownish-green hue and slender fronds, it primarily grows along the North Atlantic coasts. Renowned for its rich reserves of active substances—such as alginate, polyphenols, fucoidan sulfate, and ascophyllan—it has long been used in large-scale industrial production of iopamidol. Beyond industry, its abundant nutrients also make it a promising candidate for nutritional food development.
Ecklonia maxima, commonly known as giant kombu, falls under the genusEcklonia, family Alariaceae, order Laminariales, and phylum Phaeophyta. Native to the coasts of South Africa and Chile, it features a tough outer layer that resembles grayish-brown tree bark. Current research onEcklonia maximafocuses largely on its cultivation distribution, polyphenol extraction, and biological activities; studies have confirmed its antibacterial, antiviral, and antioxidant properties. However, systematic analysis of its nutritional composition remains limited in China, leaving its full development potential untapped.
Macrocystis(giant kelp) belongs to the family Lessoniaceae, order Laminariales, class Phaeophyceae, and phylum Phaeophyta. It is widely distributed across oceanic regions, including Oceania, the Pacific coasts of North America, and the southern coastal areas of South America. Among the most well-knownMacrocystisspecies,Lessonia trabeculata(LF) andLessonia nigrescens(LN) thrive along the Pacific coasts of South America. The Peru Current provides an ideal growth environment for these species, establishing Chile and Peru as major global algae-producing regions.Lessonia trabeculata(LF) typically grows in areas with moderate to high water flow in northern Chile, occasionally colonizing sheltered habitats. In contrast,Lessonia nigrescens(LN) is distinguished from other local species by its large, robust, and spiny fronds—each species has evolved unique adaptations to its ecological niche(see Fig 1 below).
Fig. 1 Samples of Ascophyllum nodosum，Ecklonia maxima，Lessonia trabeculata and Lessonia nigrescens
In-Depth Analysis of Nutritional Components
Basic Nutritional Components: High-Protein, Low-Fat Quality Ingredients
All four brown algae species share striking similarities in their basic nutritional profiles, defined by high protein, low fat, and high dietary fiber—traits that make them ideal for healthy diets(see Table 1 below).
Table 1 Nutrient component of different brown algaes
Moisture content varies significantly across species:Ascophyllum nodosumandEcklonia maximahave notably higher moisture levels than the twoLessoniaspecies, a difference attributed to their growth environment humidity and structural adaptations. Ash content, which reflects mineral accumulation, is highest inAscophyllum nodosum(29.60%), indicating its rich mineral reserves, whileEcklonia maximahas the lowest ash content (17.90%).
Crude protein, a cornerstone of biological function, is consistently high across all four species (8%–10%). Though minor variations exist, these levels ensure reliable protein supplementation for humans and other organisms. Crude fat content is uniformly low:Lessonia nigrescens(LN) has the lowest fat content (0.30%), whileEcklonia maximahas the highest (0.90%)—a trait that aligns with modern dietary preferences for low-fat foods.
Dietary fiber, critical for gut health, exhibits significant interspecies differences. Total dietary fiber content follows the order:Ecklonia maxima>Lessonia trabeculata(LF) >Lessonia nigrescens(LN) >Ascophyllum nodosum.Ecklonia maximastands out with a total dietary fiber content of 58.70%, including an impressive 48.60% insoluble dietary fiber—far exceeding the other three species. This makes it an excellent source of dietary fiber for fortifying food formulations. Insoluble dietary fiber promotes intestinal peristalsis and aids digestion, while soluble dietary fiber supports metabolism by lowering postprandial blood glucose, cholesterol, and insulin responses.Ecklonia maximaalso leads in soluble dietary fiber (9.64%), followed byAscophyllum nodosumandLessonia nigrescens(LN), withLessonia trabeculata(LF) having the lowest levels—highlighting compositional diversity within theLessoniagenus.
Alginate, an anionic polysaccharide, forms gels when cross-linked with hydrogen ions or multivalent metal cations (excluding Mg²+ and Hg²+), making it invaluable in food and industrial applications. Its content directly determines industrial utility:Ecklonia maximahas the highest alginate content, followed byLessonia trabeculata(LF), whileAscophyllum nodosumhas the lowest (33.2 g·100g⁻¹)—a key consideration for targeted industrial use.
Mannitol, a hexitol with multifunctional applications in medicine, food, chemical engineering, and electronics, also protects cells from reactive oxygen damage.Lessonia nigrescens(LN) has the highest mannitol content (11.9 g·100g⁻¹), whileEcklonia maximahas the lowest (3.5 g·100g⁻¹)—a difference that enables directional extraction for specific industries.
Iopamidol, a primary product of the algae industry, follows the content order:Lessonia nigrescens(LN) (48.99 g·100g⁻¹) >Ecklonia maxima(48.31 g·100g⁻¹) >Lessonia trabeculata(LF) (47.48 g·100g⁻¹) >Ascophyllum nodosum(40.88 g·100g⁻¹). However, the hard texture ofEcklonia maximaandLessonia trabeculata(LF) complicates industrial preprocessing, reducing iopamidol yield—a practical challenge for manufacturers.
Amino Acid Composition: Balanced, Comprehensive Nutritional Support
Amino acids, the building blocks of proteins, directly influence protein quality through their type, content, and proportion. All four brown algae species contain 18 amino acids, including 8 essential amino acids, 2 semi-essential amino acids, and 8 non-essential amino acids—ensuring a complete nutritional profile(see Table 2 below).
Table 2 Aamino consist of different brown algaes
Among individual amino acids, aspartic acid (Asp), glutamic acid (Glu), and alanine (Ala) are particularly abundant.Lessonia trabeculata(LF) has the highest Asp content, significantly exceeding the other three species.Lessonia trabeculata(LF) andLessonia nigrescens(LN) also have higher Glu levels thanEcklonia maximaandAscophyllum nodosum. For alanine,Lessonia nigrescens(LN) leads (0.76 g·100g⁻¹ protein), followed byAscophyllum nodosumandLessonia trabeculata(LF), withEcklonia maximahaving the lowest content. As key flavor amino acids, Asp and Glu contribute to the algae’s distinctive umami taste—an asset for food processing.
Essential amino acid content varies by species:Lessonia nigrescens(LN) has the highest total essential amino acids (3.13 g·100g⁻¹ protein), followed byAscophyllum nodosum(2.77 g·100g⁻¹ protein), withEcklonia maximaandLessonia trabeculata(LF) having similar, lower levels (2.53 g·100g⁻¹ protein and 2.62 g·100g⁻¹ protein, respectively). According to FAO/WHO standards, proteins with an essential amino acid-to-total amino acid (EAA/TAA) ratio of ~40% are considered high-quality. The EAA/TAA ratios of the four species range from 30.93% to 36.30%, withAscophyllum nodosum(36.30%) being closest to the ideal ratio—making it a superior protein source.
Delicious amino acids (DAA) directly impact flavor quality, with DAA/TAA ratios ranging from 37% to 41% across species:Lessonia trabeculata(LF) >Lessonia nigrescens(LN) >Ecklonia maxima>Ascophyllum nodosum. These high DAA levels enhance the algae’s umami, giving them a natural edge in food processing.
Amino Acid Score (AAS) and Essential Amino Acid Index (EAAI) are critical metrics for protein quality. AAS results show that tyrosine + phenylalanine (Tyr + Phe) scores highest across all species, while tryptophan (Trp) scores lowest (see Table 3 below).
Table 3 AAS of essential amino acids for different brown algaes
Notably, lysine scores forEcklonia maximaandLessonia nigrescens(LN), and valine scores forLessonia nigrescens(LN), all exceed 100—confirming these algae as rich sources of tyrosine, phenylalanine, lysine, and valine for essential amino acid supplementation.
All four species share tyrosine + phenylalanine as their first limiting amino acid, but their second limiting amino acids differ: lysine forAscophyllum nodosumandEcklonia maxima, and valine forLessonia trabeculata(LF) andLessonia nigrescens(LN). Overall, their essential amino acid scores surpass FAO/WHO standards, indicating balanced, high-quality amino acid profiles. EAAI follows the order:Lessonia nigrescens(LN) >Ascophyllum nodosum>Ecklonia maxima>Lessonia trabeculata(LF)—establishingLessonia nigrescens(LN) as the top choice for protein-focused product development.
Fatty Acid Composition: Nutritious, Functional Active Components
Fatty acids serve as vital energy sources for organisms, with unsaturated fatty acids offering additional physiological benefits—making them valuable in healthcare and medicine. Though the four brown algae species have low total fatty acid content (2.27–4.43 mg·g⁻¹), they boast diverse fatty acid profiles, including saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) (see Table 4 below).
Table 4 Composition and content of fatty acids of different brown algaes
Fatty acid proportions vary by species:Lessonia nigrescens(LN) has a unique order of SFA > PUFA > MUFA, while the other three species follow SFA > MUFA > PUFA. This difference reflects species-specific adaptations to their growth environments.
MUFA accounts for over 23.00% of total fatty acids in all four species, withEcklonia maximahaving the highest MUFA content (30.60%). MUFA supports lipid metabolism and cardiovascular health. ω-9 fatty acids, a key subset of MUFA, lower blood glucose, regulate blood lipids, and reduce blood pressure—reducing cardiovascular disease risk. Notably, ω-9 fatty acids make up 100% of PUFA inAscophyllum nodosum, highlighting its potential for cardiovascular health products.
PUFA, especially ω-3 and ω-6, are essential fatty acids that the human body cannot synthesize independently.Lessonia nigrescens(LN) has the highest PUFA content (1.41 mg·g⁻¹), followed byEcklonia maxima(1.19 mg·g⁻¹) (no significant difference between the two).Ascophyllum nodosumandLessonia trabeculata(LF) have significantly lower PUFA levels (~40.43% ofLessonia nigrescens(LN)).Lessonia nigrescens(LN) also leads in ω-3 content (0.45 mg·g⁻¹), while ω-3 is undetectable inLessonia trabeculata(LF). For ω-6,Ecklonia maxima(1.09 mg·g⁻¹) andLessonia nigrescens(LN) (0.96 mg·g⁻¹) are the richest sources—offering diverse options for functional fatty acid extraction.
Inorganic Elements: A Diverse Mineral Treasure Trove
Inorganic elements are essential for biological processes, supporting metabolism and overall health. The four brown algae species are rich in macroelements, microelements, and trace elements, with significant interspecies differences (see Table 5 below).
Table 5 Contents of inorganic elements in different brown algaes
Macroelements—K, Na, and Ca—are abundant in all species.Ascophyllum nodosumhas the highest K (8.71×10⁴ mg·kg⁻¹) and Na (4.71×10⁴ mg·kg⁻¹) contents, whileEcklonia maximaandLessonia trabeculata(LF) lead in Ca (both >2.0×10⁴ mg·kg⁻¹). These macroelements make the algae ideal for nutritional supplements, supporting human, animal, and plant health.
Iodine (I), an essential trace element for thyroid hormone synthesis, is the second most abundant inorganic element.Lessonia nigrescens(LN) has the highest iodine content (2.19×10³ mg·kg⁻¹)—3.59 times that ofEcklonia maxima—making it a premium raw material for algae-derived iodine products and iodine deficiency prevention.
Microelements Fe, Zn, and Se play critical roles in growth, development, and immune function: Fe supports hemoglobin synthesis (alleviating anemia), Zn enhances immunity, and Se protects cells from oxidative damage.Ascophyllum nodosumexcels in microelement content, with Fe (542.00 mg·kg⁻¹), Zn (13.90 mg·kg⁻¹), and Se (0.27 mg·kg⁻¹) levels significantly exceeding the other three species—positioning it as a top choice for trace element-fortified products.
Heavy metal content is a key safety indicator. According to GB 2762-2022 and NY/T 1709-2021, the maximum allowable levels of inorganic As and Pb in algae are 1.5 mg·kg⁻¹ and 1.0 mg·kg⁻¹, respectively. All species meet these standards exceptAscophyllum nodosum, whose Pb content (4.43 mg·kg⁻¹) exceeds the limit. This may result from environmental pollution in its growth waters or species-specific Pb accumulation. Manufacturers must monitor heavy metal levels, especially forAscophyllum nodosum, and adopt processing techniques to reduce Pb content and ensure product safety.
Application Potential of Brown Algae and Innovative Agricultural Uses
Multi-Industry Application Value
With their rich nutrients and unique active substances, the four brown algae species have widespread applications across industries. In the food sector, their high-protein, low-fat, high-fiber profiles make them ideal for healthy food development—including dietary fiber-fortified products, nutritional supplements, and functional beverages.Ecklonia maxima, with its exceptional dietary fiber content, can be used as a fiber additive in bread, biscuits, and yogurt to enhance nutrition and texture.Lessonia nigrescens(LN), with its high-quality protein, is suited for high-protein nutritional foods.
In algae chemical engineering, extracts like alginate, mannitol, and iopamidol have diverse industrial uses: alginate for food preservation, cosmetic additives, and pharmaceutical excipients; mannitol for dehydrating agents, sweeteners, and resin synthesis; and iopamidol for medical contrast agents.Ecklonia maxima(high alginate),Lessonia nigrescens(LN) (high mannitol and iodine), andAscophyllum nodosum(high iopamidol) each offer targeted advantages for industrial production.
In medicine and healthcare, active components like polyphenols, fucoidan sulfate, and unsaturated fatty acids provide antibacterial, antiviral, antioxidant, lipid-regulating, and cardiovascular protective benefits.Ecklonia maxima’s polyphenol extracts can be used in natural preservatives and health products;Ascophyllum nodosum’s fucoidan sulfate shows promise in immune regulation and anti-tumor research; and the ω-3/ω-9 fatty acids in all four species support cardiovascular health product development.
Agricultural Application Prospects
Amid the global shift toward sustainable agriculture, green, eco-friendly, and efficient biostimulants have become a priority. Brown algae extracts—rich in polysaccharides, amino acids, minerals, and growth regulators—offer immense potential in agriculture, providing comprehensive support for crop growth and driving green agricultural development.
Polysaccharides (e.g., alginate, fucoidan sulfate) in brown algae extracts improve soil structure, enhance water and fertilizer retention, and balance soil microbial communities. In adverse conditions (drought, salinization), these extracts help soil retain moisture, alleviate stress on crops, and boost stress resistance. They also act as soil conditioners, reducing heavy metal pollution and creating a healthy growth environment for crops.
Amino acids and minerals in the extracts provide direct nutritional support for crops: amino acids promote photosynthesis and protein synthesis, improving yield and quality; minerals like K, Ca, Fe, and Zn address nutrient deficiencies and enhance disease resistance. For example, Fe increases chlorophyll content to boost photosynthesis, while Zn promotes flower bud differentiation and fruit development.
Natural growth regulators (e.g., auxin, cytokinin, gibberellin analogs) in the extracts regulate crop growth: soaking seeds in extracts improves germination rate and seedling root development; foliar spraying enhances stem/leaf growth and dry matter accumulation; and application during fruit expansion promotes fruit growth and quality.
Additionally, active components in the extracts inhibit pathogenic bacteria, enhancing crop immunity and reducing pests and diseases. Unlike chemical pesticides, brown algae extracts are eco-friendly, residue-free, and aligned with green agriculture goals. Field trials on vegetables, fruits, and grains have confirmed their effectiveness in reducing pests, increasing yield, and improving quality—establishing them as a cornerstone of sustainable farming.
Ascophyllum nodosumandEcklonia maximastand out for agricultural use:Ascophyllum nodosum’s fucoidan sulfate and polyphenols enhance stress resistance and antibacterial activity, whileEcklonia maxima’s high fiber and alginate content supports soil improvement and nutrient supply. Their extracts offer holistic crop support, advancing sustainable agricultural practices.
Conclusion
Ascophyllum nodosum,Ecklonia maxima,Lessonia trabeculata(LF), andLessonia nigrescens(LN)—four brown algae species from the ocean—are nature’s nutritional gifts. Their high-protein, low-fat, high-fiber profiles, balanced amino acids, diverse fatty acids, and rich minerals make them valuable across food, chemical engineering, and medicine. In agriculture, their extracts provide soil improvement, nutrient supply, stress resistance, and growth regulation—offering a sustainable solution for green farming.
As agricultural technology advances, marine biological resources like brown algae will play an increasingly vital role in agriculture. As natural biostimulants, brown algae extracts can replace chemical fertilizers and pesticides, reduce agricultural pollution, improve food safety, and drive agricultural modernization.
Dora Agri-Tech is committed to providing world-leading biostimulants. If you are interested in the algae extracts of Ascophyllum nodosum and Ecklonia maxima, please contact us.
