The exploitation of marine biomass, particularly seaweeds, presents significant opportunities for sustainable biopesticide production. Seaweeds, or macroalgae are diverse photosynthetic organisms found in marine environments, rich in bioactive compounds such as terpenoids, polyphenols, and sulphated polysaccharides. These compounds exhibit potent pesticide properties, offering environmentally friendly alternatives to conventional chemical pesticides. The biopesticides derived from seaweeds are biodegradable, exhibit low toxicity to non-target organisms, and align with the principles of environmental sustainability. The growing demand for organic and sustainable agricultural products further underscores the economic potential of seaweed-based biopesticides. However, challenges such as scalability of production, extraction efficiency, and standardization of bioactivity must be addressed to realize this potential fully. Advances in biorefinery approaches, extraction technologies, and formulation techniques are critical to overcoming these challenges. Additionally, ongoing research into the synergistic effects of different seaweed compounds and the development of innovative delivery systems will enhance the efficacy and commercial viability of seaweed-derived biopesticides. This review highlights the promising role of seaweeds in biopesticide production, emphasizing the need for continued research and interdisciplinary collaboration to integrate these natural compounds into sustainable agricultural practices.
Introduction
Marine environments encompass more than 70% of Earth’s surface, hosting approximately half of the world’s biodiversity among its myriad species. Algae live in the upper oceanic layer, which makes up two thirds of the earth. The term “seaweed,” sometimes known as “macroalgae” refers to a broad group of organisms with various traits and applications. Natural substances obtained from marine species have been essential for everyday nourishment, act as sustainable source of alternative nutrition and prescribed for prevention of illness throughout history. Currently, the seaweed industry is characterized by a high species concentration, notable regional variations, and rapid expansion. The amount of seaweed that has been grown were increased by an incredible thousandfold since 1950.
In 2021, global seaweed farming reached 35.2 million tons (live weight) (UNCTAD and FAO 2023) the seaweed industry’s market value is forecasted to increase seven-fold, to $85 billion by 2026. Out of 12,000 species, world seaweed production is concentrated in only five broad groups, and just 27 seaweed species items were reported cultivated in 2019. Geographically, the seaweed industry is dominated by Asia (mostly East and South Asia) with 99.5 per cent (35 million tons) of all production by volume in 2021 (FAO 2023). In today’s world, as marine resources continue to decline, there is an opportunity to utilize resources such as seaweed, which can be easily replenished and may even aid in the regeneration of the ecosystems that support them. (World Bank 2023a). Enhanced sustainable seaweed production and improved value chains can provide significant benefits for both the environment and the economy.
Seaweeds are being used as the raw materials for many industrial productions like agar, alginate and carrageenan but they continue to be widely consumed as food in Asian countries. Trade in seaweed and innovative blue food commodities is expected to become more significant as a result of climate change’s danger to the sustainability of many local crops and the regularity of harvests (UNCTAD and FAO 2023). The seaweed business has grown significantly thus far, providing a wide range of prospects for future expansion, particularly for women who are increasingly involved in labor-intensive production and processing. Since more seaweed production may help to the people, environment, and an economy, these economic prospects should be taken advantage to the fullest extent possible. Attention to marine resources has been accelerated the exploration and utilization of green seaweeds for greater economic value.
Over the past decade, the marine ecosystem has garnered considerable attention from researchers and industrialists due to the presence of organisms producing compounds with notable biological activity. Macroalgae, a diverse group of photosynthetic organisms inhabiting marine waters, particularly stand out as promising subjects for research (Pereira 2021). Due to the increase in industrial demand for new bio sourced molecules, several types of biomasses are being exploited for the identification of bioactive metabolites and techno-functional biomolecules that are suitable for the subsequent uses in cosmetic, food and pharmaceutical fields.
Seaweed plays the crucial role for marine ecosystems because it provides an environment and food source for a wide range of aquatic creatures. It also provides tremendous deal of promise for commercialization when used as an organic fertilizer in agriculture to make up for plant nutrients such as nitrogen, phosphorus, and potassium deficiencies. The main role of biopesticide products is marketed either to fight leaf diseases, root diseases, or fruit storage diseases. Great natural alternative could be seaweeds, which have nourishment property, yet performs pesticide role and will be still biodegradable. This review paper mainly focuses on opportunities and challenges in biopesticide production using marine biomass seaweeds.
Definition of marine biomass (seaweeds)
Marine seaweed is a type of algae that can perform photosynthesis, which produces oxygen and absorbs carbon dioxide, with the support of a class of green pigments known as chlorophyll. Algae are categorized as macroalgae, which are smaller than microalgae and only visible under a microscope. Macroalgae can reach a maximum depth of 65 m and are more diverse in the oceans. For this reason, “algae” is often used to refer to “marine macroalgae or seaweeds.”. Seaweed is one form of marine material that has demonstrated inherent biofuel potential.
Biorefinery approaches to seaweed biomass
Biorefinery approaches to utilizing seaweed biomass focus on integrating the extraction of bioactive compounds for potential use as biopesticides along with other bioproducts and biofuels. The entire potential of seaweed can be realized by using a biorefinery concept, which will minimize waste and maximize product yield. In seaweed biorefineries, different procedures like fermentation, extraction, and purification would be used to separate chemicals that have pesticidal qualities (Fig. 1). The benevolent and biodegradable characteristics of these chemicals set them apart from synthetic insecticides. The adaptability of seaweed is highlighted by research in arena of biorefinery, which suggests its usage in food and fuel industries as part of an integrated resource management strategy.
Bioactive compounds and pest management
Seaweeds, with their diverse array of species, offers a rich source of bioactive compounds that have potential uses in pest management in agriculture. As a source of biopesticides, different types of seaweeds-specifically brown, red, and green varieties-have shown pest-repellent properties that can be harnessed for agricultural and horticultural applications. Researchers have identified bioactive compounds in seaweeds, such as Ulva ohnoi and Derbesia tenuissima, that can potentially be utilized as effective biopesticides. The controlled land-based techniques used to grow these seaweeds enable them as like biomass to be produced in a consistent amount and quality. The commercial manufacture of biopesticides depends on this uniformity since it guarantees the extracted compounds’ efficacious and dependable pesticidal qualities. Because these are biodegradable and environmentally benign, these bioactive chemicals could act as a sustainable substitute for chemical pesticides.
Challenges and potential
While the scenarios of using seaweed biomass for pesticide production are promising, several challenges need addressing to make this a viable alternative. These challenges include scalability of production, extraction efficiencies, and the economic viability of the process. There is also the issue of standardizing the bioactivity of the extracts, as natural products can vary significantly in their composition and efficacy. Addressing these issues requires innovative technological solutions and further research into cultivation methods, extraction techniques, and bioactivity assays. Nevertheless, the potential environmental benefits of reducing synthetic pesticide use present a compelling case for continued investment and research in this field. Even though algal aquaculture technology has advanced significantly over the past 70 years, particularly in Asia, America, and Europe, there is still much to be done to advance both the science and the associated societal acceptance. Creating strains that are resistant to heat, grow quickly, produce a lot of compounds of interest, are resistant to morbidity, and have the ability to prevent fouling is one of the biggest challenges. Another is creating effective and affordable hatcheries that can withstand storms in the open ocean. Research is still being done to better understand how chemicals generated from seaweed interact with human physiology and the environment, develop novel formulations, and maximize their usage in biomedical and pharmaceutical applications. Seaweed exhibits good biocompatibility in a range of contexts, including nutritional advantages, biomedical applications and environment sustainable products. Realizing its full potential while maintaining environmental sustainability and safety for human use requires ongoing study and ethical harvesting methods. Seaweed-based biopesticides are gaining popularity and are the subject of increasing study; however, there are still issues with extraction method standardization, formulation stability, manufacturing scalability, and regulatory approval procedures. It will be essential to overcome these obstacles in order to promote and commercialize adoption.
Alternative bioproducts from seaweed
The utilization of seaweed biomass extends beyond pesticide production to include other valuable bioproducts like biodiesel and alginate. This diversification can provide economic benefits and increase the sustainability of seaweed cultivation practices. For instance, the valorisation of Caribbean Sargassum biomass not only addresses the environmental issues caused by its overabundance but also explores its potential in producing high-value products. Such initiatives can create new revenue streams for communities affected by Sargassum influxes while contributing to the development of sustainable bioproduct industries (Fig. 2). These efforts underline the broader applicability and economic potential of seaweed biomass in the bioeconomy. Utilizing seaweeds to produce pesticides and repellents against mosquito species and as a source of environmentally friendly materials is an additional strategy. Numerous studies have demonstrated the health advantages of seaweed polysaccharides, such as carrageenans and alginates, as well as their assistance for the production of biopolymeric films and biodegradable packaging. Ecosystems and aquatic life are impacted by the pervasiveness of plastics and microplastics in the ocean, which presents serious environmental challenges. Consequently, it is critical to use biopolymers made from seaweed in a sustainable manner. By using biodegradable substitutes for plasticizers, this method can assist safeguard the environment. The organic, nutraceutical and biofertilizer industries have shown interest in seaweeds as a source of macronutrients, micronutrients, and bioactive components. The biomedical application of sea weed depend on its biocompatibility, compounds derived from seaweed, like carrageenan and alginate. Because of their biodegradability and gel- forming properties, they are utilized in tissue engineering, medication delivery systems, and wound dressings. Applications of seaweeds in biotechnology are numerous. Species in the phylum Rhodophyta, class Phaeophyceae, phylum Ochrophyta, and phylum Chlorophyta are valuable to the food, cosmetic, pharmaceutical, and nutraceutical sectors because of the range of bioactive substances in their composition.
Importance of seaweeds in biopesticides production
The field of sustainable agriculture has shown a great deal of interest in seaweeds, especially with regard to their potential for producing Biopesticides (Fig. 3). Their significance arises from a range of distinct biochemical characteristics and environmental advantages, rendering them a compelling substitute for artificial pesticides. An in-depth examination of seaweeds’ significance in the synthesis of biopesticides is provided below:
Rich source of bioactive compounds
A diversified genre of marine life, seaweeds are prolific in biologically active compounds exhibiting antiviral, antifungal, and antibacterial properties. Among these components are fatty acids, polysaccharides, pigments, and phenolic substances. These substances are extracted and utilized to generate biopesticides, which are less destructive to non-target creatures than traditional pesticides and biodegradable. Research indicates that utilising seaweed extracts to build systemic resistance, plants can strengthen their innate defences against illness and pests. The benefits of seaweed are mostly due to its combination of minerals, vitamins, phenols, polysaccharides, sterols, and other bioactive ingredients. These compounds are thought to possess antioxidant, anti-inflammatory, anti-cancer, antibacterial, and anti-diabetic effects. Natural pigments (NPs) like carotenoids, chlorophylls, and phycobiliproteins are found in edible seaweed, and their advantageous medicinal qualities have made them well- known functional constituents.
Being the most prevalent type of macroseaweed, green seaweed is a valuable marine biological resource. It is abundant in a number of fatty acids, amino acids, dietary fibers, polysaccharides, polyphenols, pigments, and other active ingredients that are vital to many biological processes, including immunoregulation, antioxidant activity, and the anti-inflammatory response. The exploration and use of green seaweeds for increased economic value has intensified in recent years due to increased attention to marine resources. Green seaweed is a major source of several lipids and proteins. Additionally, seaweed contains lectins, glycoproteins, and phycobiliproteins (Table 1).
| Seaweed species | Biopesticide type | Potential bioactive compounds |
| Ascophyllum nodosum | Algicides | Fucoidans, polysaccharides, polyphenols |
| Fucus vesiculosus | Herbicides | Phlorotannins, fucoidans, polyphenols |
| Gracilaria spp. | Insecticides | Phycobiliproteins, polyphenols, sulfated polysaccharides |
| Ulva lactuca | Fungicides | Lectins, sulfated polysaccharides, polyphenols |
| Sargassum spp. | Nematicides | Peptides, alkaloids, polyphenols |
| Porphyra spp. | Rodenticides | Peptides, alkaloids, polyphenols |
| Eisenia bicyclis | Larvicides | Fucoidans, polyphenols, polysaccharides |
| Laminaria digitata | Repellents | Phlorotannins, fucoxanthin, polyphenols |
Environmental sustainability
The use of seaweeds in biopesticide production aligns with the principles of environmental sustainability. Seaweeds grow abundantly in marine environments without the need for freshwater, arable land, or synthetic fertilizers, making them a low-impact resource. Moreover, seaweed cultivation can contribute to carbon sequestration and help mitigate the effects of eutrophication in marine ecosystems. By integrating seaweed-based products into agricultural practices, it is possible to reduce the ecological footprint of pest management strategies. Using the natural substances found in seaweed, seaweed-based biopesticides help manage pests in agricultural settings while having fewer of an adverse effect on the environment than synthetic pesticides. The three aspects of seaweed’s potential contributions to sustainability and environmental stewardship-carbon sequestration, mitigating ocean acidification, and applying biopesticides-represent distinct aspects of these contributions. Since seaweed’s capacity to absorb CO2 is essential to marine ecosystems and the worldwide cycling of carbon, its usage as biopesticides primarily targets food production and sustainable agriculture. This involves lowering the amount of chemical residues in food and the pollution that conventional pesticide use causes to the environment.
Safety and biocompatibility
Seaweed-based biopesticides are increasingly recognized as safe alternatives to chemical pesticides due to their natural origin, biodegradability, and minimal environmental impact. Seaweed-based biopesticides are also recognized as safe for humans and animals. This safety profile is particularly advantageous for crops used in human and animal foods, aligning with the global trend towards organic and clean-label products.
Economic benefits
The utilization of seaweeds in the manufacturing of biopesticides has significant economic ramifications. Seaweeds are a renewable resource that can be responsibly harvested to provide a steady supply of raw materials for the development of biopesticides. Compared to synthetic chemicals, which are frequently made from non-renewable petroleum sources, might be more affordable. Moreover, the increasing market for eco-friendly and organic products creates fresh prospects for seaweed-based biopesticides.
Innovation and research opportunities
Seaweeds offer vast potential for innovation in the field of agricultural biotechnology. The diverse chemical makeup of seaweeds presents opportunities for the discovery of novel bioactive compounds with unique modes of action against plant pathogens and pests. Ongoing research and development efforts are crucial to unlock these potentials, refine extraction and formulation techniques, and ensure the efficacy and stability of seaweed-based biopesticides. In conclusion, seaweeds hold a pivotal role in the future of biopesticides production, offering a sustainable, safe, and economically viable alternative to synthetic pesticides. Their integration into pest management systems represents a forward step towards more sustainable agricultural practices, highlighting the convergence of environmental stewardship and technological innovation.
Overview of biopesticides
Natural, biologically based substances called biopesticides are applied to plants in forests, gardens, agricultural farms, and other areas to manage a variety of agricultural pests and they also helps to enhance crop production. Diverse biopesticide kinds have been developed from diverse sources. To improve the sustainability andefficacy of pest management, researchers are continuously looking for new sources of biopesticides, such as microbial strains, plant extracts, and natural chemicals.
Seaweeds as a source of biopesticides
Several studies have investigated the potential of various seaweeds in the production of biopesticides, focusing on their bioactive properties that can be utilized in controlling plant pathogens and enhancing agricultural sustainability (Fig. 4). Researchers reported 10,000 spices of marine macroalgae, known as seaweeds, are microscopic, multicellular, photosynthetic eukaryotic creatures Based on pigmentation, morphology, and anatomical characteristics, seaweeds are divided into three main groups: brown seaweeds (Phaeophyta), red seaweeds (Rhodophyta), and green seaweeds (Chlorophyta).
Types of seaweeds with pest-repellent properties
Brown seaweeds (phaeophyta)
Brown seaweeds vary in dimension from small filamentous kinds to large/giant complex seaweeds, making them some of the largest and most complex marine algae. Iodine and other special secondary metabolites, such phlorotannin, are abundant in marine algae. Researchers are giving these phenolic compounds a lot of attention because of their biological activity, which includes anti-viral, anti-cancer, cholesterol-lowering, and many other effects. Brown algae comprise primarily of polysaccharides with variety of unique physical and chemical properties due to their diverse structures. These properties include immunomodulation, antibacterial, antioxidant, prebiotic, antihypertensive, antidiabetic, antitumor, and anticoagulant activities, among many more, and help to moderate a wide range of biological activities. Alginate, laminarin, and fucoidan are the three main types of polysaccharides found in brown algae. The potency of brown seaweeds, such as Ascophyllum nodosum and Sargassum species, in enhancing plant resistance to pests and diseases has been the object of much research. These seaweed extracts have the ability to give plants systemic acquired resistance, which reduces their vulnerability to insect and microbial pathogen attacks.
Red seaweeds (rhodophyta)
Red seaweeds are the largest group of seaweeds, including around 6000 different species. They are known for having a high concentration of potential molecules like vitamins, minerals, phycobiliproteins, essential fatty acids, and other secondary metabolites, as well as bioactive sulphated polysaccharides like agar and carrageenan. Because of their antibacterial and antifungal properties, species including Porphyra and Laurencia have demonstrated promise in the treatment of pests. Specifically, the carrageenan found in red seaweeds have the ability to impede the growth of fungi, which is advantageous for managing fungal diseases in agricultural settings. Furthermore, certain red seaweeds have been utilized to create nematicides that effectively combat nematodes that harm a variety of crops.
Green seaweeds (chlorophyta)
The intertidal zone is inhabited chiefly to green seaweeds. Common green seaweed species are found in the genera Ulva, Enteromorpha, Chaetomorpha, Codium, and Caulerpa. Ulva lactuca, U. prolifera, and U. linza are the four significant green seaweed species in the genus Ulva. Green seaweeds, like their brown and red counterparts, contain a variety of bioactive compounds, including peptides, fatty acids and phenolics, which exhibit biological activities against pests. Monostroma, Ulva and Caulerpa are commercially important seaweeds. Especially, Ulva (also known as sea lettuce) have been researched for their capacity to produce substances that repel insects and inhibit the growth of harmful bacteria and fungi. Green seaweeds are often easier to process and extract, making them an attractive option for biopesticide formulation.
Integration into agricultural practices
The integration of seaweed-based biopesticides into agricultural practices involves the formulation of these extracts into usable products such as sprays, powders, or integrated pest management systems. Seaweed extracts promote early seed germination and establishment, boost root growth, increase leaf chlorophyll, improve crop performance and elevate resistance to biotic/abiotic stress .
Future research directions
Ongoing research is crucial to fully understand the spectrum of bioactive compounds in seaweeds and their mechanisms of action against various agricultural pests. Future studies are needed to standardize extraction methods, improve the stability and efficacy of seaweed-based biopesticides, and ensure their compatibility with other pest management strategies. Additionally, exploring the synergistic effects of combining different types of seaweed extracts could lead to the development of broad-spectrum biopesticides that are more effective and environmentally benign. In conclusion, seaweeds as a source of biopesticides represent a promising area of biotechnological innovation in agriculture, leveraging the natural pest-repellent properties of marine algae to develop safer, more sustainable pest management solutions.
Bioactive compounds in seaweeds
Seaweeds contain elaborate secondary metabolites that play a significant role in the defence of the host against predators and parasites which offer a potential novel approach to control population of plant parasitic nematodes. Seaweeds are an abundant source of bioactive compounds that hold potential for various applications, including the development of natural products such as biopesticides (Fig. 5). The bioactive compounds such as terpenoids, polyphenols, and sulfated polysaccharides, in particular, have been extensively studied for their biological properties. Here is an elaboration on these key compounds found in seaweeds.
Terpenoids
Terpenoids, also known as isoprenoids, are a large group of organic chemicals that are found in nature. They are made from five-carbon isoprene units that are arranged in a variety of ways. Terpenoids in seaweeds are effective natural pesticides due to their strong antifungal and antibacterial properties. They protect seaweeds from microbial invasions and herbivorous marine animals in crucial ways. Terpenoids, for instance, are produced by certain species of brown and red seaweed that repel marine herbivores and prevent fouling organisms from colonizing the area. Biopesticides that similarly protect agricultural crops from pests and diseases can be developed using these properties. Terpene based biopesticides show promise against aphid pests of ornamental crops.
Polyphenols
Another significant class of compounds found in seaweeds are polyphenols, which are well-known for their antioxidant properties. The polyphenolic compounds such as phlorotannins, bromophenols, flavonoids, phenolic terpenoids, and mycosporine-like amino acids. In the brown seaweeds, the phlorotannins are the major polyphenolic class found only in the marine brown seaweeds. On the other hand, the largest proportion of phenolic compounds present in green and red seaweeds are bromophenols, flavonoids, phenolics acids, phenolic terpenoids. Phlorotannins, a type of tannin found in earthy colored green growth, are one example of polyphenols from ocean growth that exhibit strong antibacterial and antifungal properties when it comes to biopesticides. These substances have the ability to stop the growth of several plant pathogens, which lowers the incidence of agricultural diseases. Moreover, polyphenols have the ability to stimulate defense mechanisms in plants, enhancing their resistance to attacks by microbes and rodents.
Sulphated polysaccharides
Sulfated polysaccharides are unique to marine environments and are present in a wide range of seaweeds. These substances include fucoidan, ulvan, and carrageenan, which are found in red, brown, and green seaweeds, respectively. It is well known that sulfated polysaccharides have antibacterial, antifungal, and antiviral properties. They can directly prevent the growth of bacteria or cause plants to develop resistance. For example, fucoidans have been demonstrated to strengthen plants’ defenses against fungus and viruses. Due to these characteristics, sulfated polysaccharides are crucial components of biopesticides, enhancing their viability and range of action.
The application of these bioactive compounds in agriculture as biopesticides offers a sustainable alternative to synthetic chemicals. Furthermore, the use of such natural products is often more favorable under organic farming regulations, enhancing the appeal and marketability of the produce. Crop performance may be impacted by the use of seaweed extracts and their bioactive components. Seaweed products provide many benefits for agriculture, including improved nutrient uptake, improved morphological and physiological traits, and reduced stress in plants. They have previously been shown to function in plants as both biostimulants and bioelicitors. Additionally, the Seaweed Extracts have no adverse effects on the environment and effectively stimulate plants’ natural defenses. To maximize output and minimize the need for chemical fertilizers, Seaweed Extracts can be used in conjunction with other biofertilizers.
While the potential of these bioactive compounds is significant, ongoing research is necessary to optimize their extraction, stability, and formulation for agricultural use. Advanced techniques in biotechnology and nanotechnology could play pivotal roles in enhancing the efficacy and delivery systems of seaweed-based biopesticides. Moreover, understanding the synergistic effects between different bioactive compounds could lead to the development of more effective and broad-spectrum biopesticides. The genomes of a variety of plants have now been sequenced or are close to being sequenced, researchers need to investigate the effects of seaweed extracts and components on the whole genome/transcriptome of plants to better understand the mechanisms of action of seaweed-induced growth response and stress alleviation. In conclusion, the bioactive compounds in seaweeds offer promising prospects for the development of natural and effective biopesticides. These compounds not only help in managing pests and diseases but also contribute to sustainable agricultural practices, which are crucial for the long-term health of ecosystems and human populations.
Extraction methods
Bioactive components from seaweeds must be extracted in order to properly utilize them for a variety of purposes, including the production of biopesticides. Different methods are employed to ensure the effective and successful recovery of these materials; each method has unique benefits and applications (Table 2).
| Seaweed species | Biopesticide type | Extraction method | Mechanism |
| Ascophyllum nodosum | Algicides | Supercritical Fluid Extraction | Extraction ofsulfated polysaccharides, such asfucoidan, known for their algicidal activities. |
| Fucus vesiculosus | Herbicides | Solvent Extraction | Extraction of bioactive compounds with herbicidalproperties, such as polyphenols and alkaloids. |
| Gracilaria spp. | Insecticides | Microwave-Assisted Extraction | Extraction of bioactive compounds, includingphycobiliproteins and polyphenols, withinsecticidal and larvicidal effects. |
| Ulva lactuca | Fungicides | Aqueous Extraction | Extraction of bioactive compounds with antifungalproperties, such as sulfated polysaccharides andlectins. |
| Sargassum spp. | Nematicides | Enzyme-Assisted Extraction | Release of bioactive peptides with nematicidalproperties, disruptingthe physiological processesofnematode pests. |
| Porphyra spp. | Rodenticides | Acid Hydrolysis | Hydrolysis of seaweed carbohydrates into bioactivecompounds with rodenticidal effects, such aspeptides and alkaloids. |
| Eisenia bicyclis | Larvicides | Enzymatic Hydrolysis | Enzymaticbreakdown of seaweed polysaccharidesinto fermentable sugars, fermenting into larvicida!compounds through microbial processes. |
| Laminaria digitata | Repellents | Hydrotherma Liquefaction | Conversion ofseaweed biomass into bio- oilthrough high-temperature and high-pressure conditions, producing compounds with repellentproperties. |
Aqueous extraction
Aqueous extraction is one of the simplest and most environmentally friendly methods for extracting bioactive compounds from seaweeds. This method involves using water as the solvent, which is particularly effective for extracting hydrophilic compounds such as polysaccharides and certain proteins and peptides. Aqueous extraction is favored for its safety, low cost, and minimal environmental impact. It is also suitable for compounds that are heat-sensitive, as this method can be conducted at controlled temperatures to prevent degradation of the bioactive materials. Aqueous extraction is preferred for its simplicity, sustainability, and ability to preserve the natural integrity of seaweed-derived compounds. The efficacy of aqueous extraction methods in obtaining high yields of bioactive compounds from seaweed, including polysaccharides (e.g., agar, carrageenan), polyphenols, and peptides.
Supercritical fluid extraction (SFE)
A more sophisticated and effective technique for removing lipophilic chemicals from seaweeds is supercritical fluid extraction, especially when carbon dioxide (CO2) is used. SFE functions at solvent conditions above its critical point, where it displays special characteristics that set it apart from liquids and increase its solvation power. For the extraction of terpenoids, fatty acids, and other non-polar substances, this technique is quite successful. In addition to being eco- friendly and leaving no solvent residues behind, SFE has low working temperatures, great selectivity, and helps maintain the integrity of thermolabile molecules. Moreover, SFE’s scalability makes it appropriate for industrial applications where environmental concerns and great efficiency are critical. The use of sub- and supercritical fluids for extraction is one of these technologies that is gaining more and more attention. By using these extraction technologies, the problems of selectivity and toxicity related to the use of organic solvents can be minimized. Pigments and other lipid-soluble substances can be selectively extracted through the use of supercritical carbon dioxide extraction. Seaweed bioactive compounds can be extracted using energy-efficient and selective extraction techniques. Supercritical fluid extraction (SFE) techniques were widely used by companies to extract important bioactive chemicals from seaweeds. At different temperatures, pressures, and co-solvent percentage values, the seaweed extracted using the supercritical fluid extraction method has the highest level of antioxidant activity due to its largest concentration of total phenols. Supercritical fluid extraction offers an acceptable method for the extraction of bioactive chemicals from seaweed, providing benefits over conventional extraction techniques in the areas of purity, selectivity, and environmental sustainability.
Microwave-assisted extraction (MAE)
Microwave-Assisted Extraction uses microwave energy to heat the solvent and plant material, enhancing the extraction process’s speed and efficiency. This method is particularly useful for extracting a wide range of bioactive compounds from seaweeds, including polyphenols and sulphated polysaccharides. MAE reduces the extraction time significantly, requires less solvent, and can result in higher yields compared to traditional methods. It is also noted for its ability to disrupt cell walls, facilitating the release of bioactive compounds. The rapid heating produced by microwaves leads to increased penetration of the solvent into the biomass, resulting in faster and more complete extraction.
Ultrasound-assisted extraction (UAE)
Ultrasound refers to sound waves beyond the audible frequency range (typically, > 20 kHz). UAE method has been utilized in extraction of bioactive compounds from several marine algae or even non-hydrocolloids materials. A study on the extraction of carrageenan from Hypnea musciformis, a red seaweed species and found under the same circumstances, he discovered that employing UAE-alkaline and aqueous treatment techniques produced noticeably more carrageenan yields than the traditional approach. Interestingly, nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR) methods indicated that the carrageenan obtained with these methods was highly purified and equivalent to conventional commercial carrageenan. Furthermore, the glucose polysaccharide laminarin was effectively isolated by other researchers from the Irish brown seaweed species Laminaria hyperborean and Ascophyllum nodosum. When compared to the traditional solid–liquid extraction approach, they found that for both brown seaweed species, the UAE method with HCl alteration showed the maximum extraction yield and antioxidant activity. Ultrasound-Assisted Extraction method has been extensively used in recent years in order to extract diverse BCs from an extensive spectrum of algae, especially polysaccharides like alginate and carrageenans; pigments like fucoxanthin, chlorophylls, or β-carotene; and phenolic compounds, among others. Utilizing Ultrasound-Assisted Extraction to marine algae is therefore a productive and environmentally friendly method of further exploring their profound characterization as a novel supply of BCs, especially appropriate for vegan and vegetarian diets.
Enzyme-assisted extraction (EAE)
Proteins, various binding ions like calcium and magnesium, and branching and sulphated polysaccharides make up the cuticles and cell walls of seaweed. The targeted compounds cannot be recovered from seaweed due to the physical barrier this chemical composition creates. Therefore, in order to isolate the desired molecules, it is important to break downthese complex cell walls. The EAE method offers several advantages, including its eco-friendliness and low cost. A large yield of bioactive compounds can be produced by this technique, which can change molecules that are insoluble in water into ones that are soluble. Furthermore, EAE increases the antioxidant and antiviral effects of bioactive substances while also dramatically increasing their extraction yield. Unless they are tuned, standard extraction techniques usually do not yield this kind of result.
Each extraction method has its specific implications for the commercial production of biopesticides from seaweed. For instance, aqueous extraction is highly suitable for products that require a “natural” label, while SFE and MAE provide advantages in terms of efficiency and environmental sustainability. Ongoing advancements in extraction technologies may further enhance the effectiveness and reduce the costs of these methods, promoting their wider application in the industry. Allow high yield of bioactive compounds and Improve extraction yields and its quality.Optimizing the extraction of bioactive compounds from seaweeds is essential for maximizing their potential in various applications, including biopesticides. The choice of extraction method depends on the specific compounds of interest, the intended use, and the scale of production. Continued research and development in this area are crucial for improving the sustainability and efficacy of these natural products in agricultural settings.
Challenges and limitations
Optimization of extraction processes
With a methodical approach and the use of contemporary technologies, seaweed extraction procedures are able to rendered much more productive, sustainable, and efficient. Every stage needs to be precisely customized to the unique qualities of the seaweed species and the final goods that are intended. It is critical to take into account the technical benefits of each extraction technique as well as its consequences for product quality and economic feasibility when optimizing extraction methods for the commercial manufacture of biopesticides from seaweed. Higher temperatures result in low yield of extraction and lower temperatures result in high yield of bioactive compounds. To optimize yield without compromising product integrity, alter the temperature and intensity of the extraction process. Adjust pH levels to optimize the effects of a specific seaweed bioactive components. To improve extraction efficiency, optimize the size of the seaweed particles. Utilize co-solvents to enhance the extraction yields and solubility of particular bioactive compounds. Certain beneficial compounds can be selectively extracted from seaweed. With microwave-assisted extraction techniques to achieve optimal extraction results, choose solvents that are compatible with microwave energy.
Modify power levels and extraction periods to improve quality and yield. It is important to control and monitor temperature to prevent the degradation of sensitive bioactive compounds.
Formulation and stability of biopesticides
In biopesticides, organisms like bacteria, fungi, or viruses are often encompassed in formula. Because of the intrinsic diversity of these organisms, it might be challenging to guarantee consistency in biological activity and efficacy across batches. Formulations known as biopesticides are made from substances that occur naturally like bacteria, plants, animals, and minerals. Their ability to effectively manage pests while reducing their negative effects on the environment makes them essential to sustainable agriculture. Identifying effective active ingredients from natural sources can be challenging. To identify compounds that are effective against pests and safe for the environment, a great deal of research and testing is necessary. Integrating active ingredients with inert materials (solvents, adjuvants, and carriers) while maintaining stability and effectiveness is challenging. Unfavorable component interactions or gradual ingredient degradation may affect the biopesticide’s effectiveness. The sensitivity of biopesticides to environmental factors like humidity, light, and temperature is ubiquitous. To keep them effective until they are ready to use, stability during storage and transit is essential. Biopesticides, as an alternative to synthetic pesticides, degrade faster in the field as a result of microbial activity, UV exposure, or other environmental conditions. It is difficult to make sure they endure long enough to efficiently manage pests without endangering beneficial creatures. Formulations for biopesticides need to be safe for users, non-target organisms, and applicators alike. Admixtures and carriers must be thoroughly tested and adhere to regulatory criteria in order to guarantee that they do not pose health concerns or harm the environment.
Future perspectives
Potential for seaweeds in biopesticides market
Seaweeds show great promise as environmentally friendly substitutes for conventional chemical pesticides, according to research on their potential in the biopesticide industry. Seaweeds, also known as macroalgae, are rich in bioactive substances with pesticidal qualities, including polysaccharides, polyphenols, and halogenated chemicals. These substances can function as chemicals, growth inhibitors, or repellents against infections and pests. The biopesticide industry is now beginning to understand the potential of seaweeds because of their natural components that reduce pests and improve the environment. Numerous bioactive substances, including polysaccharides (such as alginates and carrageenans), polyphenols, and terpenes, are found in seaweeds. These substances have demonstrated pesticidal effects on nematodes, fungi, and insects. An invasive seaweed that may be used as a biopesticide is Asparagopsis armata. Its exudate, when given to a model weed, has detrimental effects on energy metabolism and carotenoid metabolism, and it also dramatically increases oxidative stress. This implies that this macroalga could be used in a biopesticide cocktail, which is an environmentally friendly and long-lasting way to manage weeds.
Innovation in biopesticide technology
Nanoformulation improve the active components’ targeted delivery, stability, and bioavailability. Utilizing nanotechnology, biologically synthesized pesticides were created from inexpensive sources like seaweed, particularly green algae, since it is safe to create pesticides against a variety of pests that harm different types of crops, including fungi and bacteria. Microencapsulation helps to preserve bioactive substances, extend their release, and boost effectiveness in a range of environmental circumstances. Alginate is a biopolymer that is frequently used for this kind of microencapsulation; it is derived from seaweed. Alginate-based microcapsules that satisfy essential bacterial encapsulation criteria, such as biocompatibility and biodegradability, and that sustain long-term survival and function, have been produced as a consequence of recent advancements.
Importance of sustainable practices and environmental protection
In recent years, there has been a renewed focus on identifying sustainable alternatives to conventional chemical pesticides due to concerns about pesticide resistance, hazards to human health, and the environment. A possible solution has developed in the form of seaweed biopesticides, which effectively control pests by using natural chemicals derived from marine algae.
Conclusion
Marine biomass forms the largest component of marine ecosystems and offers numerous benefits, including nutrition, agar, algin, carrageenan production, and biofuels. Its use as a biopesticide source holds great potential for sustainable agriculture and environmental conservation. Bioactive compounds in marine organisms like seaweed, microalgae, and marine bacteria can efficiently control pests with minimal impact on ecosystems and non-target organisms. The diversity of marine biomass enables the development of tailored biopesticides for specific agricultural challenges, reducing reliance on synthetic pesticides and supporting biodiversity conservation. Despite this potential, challenges remain in scaling production, optimizing extraction, and ensuring cost competitiveness. Advanced formulation techniques like nanoencapsulation and microemulsions can improve stability and targeted delivery of bioactive compounds. Further research is essential to understand the environmental fate of seaweed biopesticides and their ecosystem impacts. With innovative approaches and policy support, seaweed biopesticides can significantly contribute to resilient crops, ecosystem preservation, and agricultural sustainability.
Dora Agri-tech commonly liquid seaweed fertilizers support formulations that can be used as bio pesticides, and also provide commonly used Natural Agriculture Surfactants.
