Excessive use of chemical fertilizer is a global concern. Arbuscular mycorrhizal fungi (AMF) are considered a potential solution due to their symbiotic association with crops. This study assessed AMF’s effects on maize yield, fertilizer efficiency, plant traits, and soil nutrients under different reduced-fertilizer regimes in medium–low fertility fields. We found that phosphorus supplementation after a 30% fertilizer reduction enhanced AMF’s positive impact on grain yield, increasing it by 3.47% with pure chemical fertilizers and 6.65% with mixed fertilizers. The AMF inoculation did not significantly affect the nitrogen and phosphorus fertilizer use efficiency, but significantly increased root colonization and soil mycelium density. Mixed fertilizer treatments with phosphorus supplementation after fertilizer reduction showed greater mycorrhizal effects on plant traits and soil nutrient contents compared to chemical fertilizer treatments. This study highlights that AMF inoculation, closely linked to fertilization regimes, can effectively reduce fertilizer use while sustaining or enhancing maize yields.

Organic farming, which is deeply rooted in traditional agricultural practices, has witnessed a profound evolution over the last century. Transitioning from a grassroots initiative resisting the industrialization of agriculture to a global industry, organic farming now plays a pivotal role in addressing contemporary challenges related to environmental health, sustainability, and food safety. Despite the growing consumer demand for organic products and market access, organic farming has its challenges. This paper discusses the origin and evolution of organic farming with an emphasis on different types of organic fertilizers, benefits, and challenges. Nutrient variability and the slow-release nature of organic fertilizer often do not meet crop demands and can substantially reduce yield. Some organic fertilizers, like manure and biosolids, can provide a higher yield benefit, but there are environmental and health risks associated with them. Weed and pest management in organic farming can be labor-intensive and increase costs. Inefficient planning of organic farming and rapid transition can also create food insecurity. This paper also gives a brief account of the current certification process for organic fertilizers and their technicalities. It showcases how the holistic approach of organic farming extends beyond production, including strategies like reducing food waste and building self-sufficient farming communities. These practices contribute to a more sustainable agricultural system, reducing environmental impacts and supporting local economies. Future technological innovations, especially in precision agriculture and bio-physicochemical models, can help in formulating targeted organic fertilizers.

以番茄‘合作908’为试材，在筛选出的3种稻壳基质中进行育苗，通过喷施5种不同浓度海藻肥，研究育苗基质和海藻肥耦合效应对番茄幼苗生长的影响。结果表明∶番茄幼苗在3种育苗基质中生长存在显著差异，以腐熟稻壳∶蛭石∶珍珠岩=6∶2∶2(T2)处理幼苗生长最健壮；喷施800倍液海藻肥处理效果最佳，其株高、茎粗、干鲜重、根系活力及壮苗指数均显著高于其他浓度处理；壮苗指数多因素方差分析结果表明：基质种类×海藻肥对壮苗指数存在互作（P=0.029），其中基质种类影响程度大于海藻肥；T2基质+喷施800倍液海藻肥处理幼苗生长最佳，根系活力和壮苗指数分别比对照提高24.04%和19.05%。此结果可以为工厂化番茄优质种苗培育提供理论依据。

This study used largemouth bass (initial average weight: 33.33 ± 1.8 g) to explore the effects of adding different brown algae extracts to feed on the fish’s growth, immunity and intestinal health. Six groups were set up: a control (Group A), 0.1% sodium alginate (Group B), 0.1% oligotriosaccharide I (Group C), 0.1% oligotriosaccharide II (Group D), 0.2% brown algae powder (Group E) and 0.2% brown algae powder enzymatic product (Group F), with three replicates of 35 fish each, and a 56-day feeding experiment. Results: Compared to Group A, Groups C, D and F had a higher specific growth rate and lower feed coefficient (p < 0.05). Group D had enhanced serum SOD activity; Group F had increased antioxidant enzyme activity and decreased MDA content (p < 0.05). All experimental groups had higher serum LZM levels (p < 0.05), with no IgM difference (p > 0.05). In the intestine, treatment groups had higher α-amylase activity (p < 0.05) and no lipase difference (p > 0.05), and Groups C, D and F had higher trypsin activity (p < 0.05). Group F had the tallest villi, Group B had the thickest muscular layer (p < 0.05), and villus width was similar among groups (p > 0.05). The experimental groups had fewer intestinal pathogenic bacteria, and Group F had improved intestinal microorganism diversity and richness (p < 0.05). In conclusion, adding 0.1% oligotriosaccharide and 0.2% brown algae powder enzymatic product to feed can promote largemouth bass growth, antioxidant capacity and immunity. The 0.2% brown algae powder enzymatic product is better for intestinal development and flora improvement.

（1. 中国科学院亚热带农业生态研究所，中国科学院亚热带农业生态过程重点实验室，畜禽养殖污染控制与资源化技术国家工程实验室，动物营养生理与代谢过程湖南省重点实验室，长沙 410125；2. 中国科学院大学，北京 100049）摘　要：本研究旨在评估海带提取物（LJE）对奶牛泌乳性能、血液生化、免疫、抗氧化指标、瘤胃发酵参数及瘤胃微生物的影响。试验采用单因素完全随机设计，选择32头体重、产奶量、胎次和泌乳天数相近的健康荷斯坦泌乳奶牛，随机分为2组，每组16头。对照组（CON组）的奶牛饲喂基础日粮，试验组（LJE组）在其基础上补喂LJE，每头每天30 g。试验预饲期为12 d，正试期为30 d。相比于CON组，添加LJE能显著提高奶牛的干物质采食量（DMI）、产奶量以及乳蛋白率，对乳脂、乳糖、体细胞数和总固形物等无显著影响，对血液生化指标无显著影响；添加LJE显著提高了血浆免疫球蛋白A（IgA）、免疫球蛋白G（IgG）和免疫球蛋白M（IgM）的含量，显著降低了血浆丙二醛的含量，提高了瘤胃总挥发性脂肪酸的含量，提高了Firmicutes门以及Succiniclasticum、Sphaerochaeta、Mucispirillum和Akkermansia属的相对丰度。综上，日粮添加LJE能够增强奶牛的机体免疫力，降低奶牛脂质过氧化的水平，有利于提高奶牛的采食量、产奶量和乳品质，对实现奶牛健康养殖具有重要意义。关键词：海带提取物；泌乳性能；免疫力；瘤胃发酵参数；瘤胃微生物中图分类号：S823.9+1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 文献标志码：ADOI：10.3969/j.issn.1007-7146.2024.06.007

Alginate, a polysaccharide found in brown seaweeds, has regularly gained attention for its potential use as a source of bioactive compounds. However, it is structurally complex with a high molecular weight, limiting its application. Alginate oligosaccharides (AOS) are small, soluble fragments, making them more bioavailable. Alginate hydrolysis by enzymes is the preferred method for AOS production. Commercially available alginate lyases are limited, expensive, and sometimes exhibit unsatisfactory activity, making the search for novel alginate lyases with improved activity indispensable. The aims of this study were to codon-optimise, synthesise, express, purify, and characterise a recombinant alginate lyase, AL2, from Flammeovirga sp. strain MY04 and to compare it to a commercial alginate lyase. Expression was successfully performed using Escherichia coli ArcticExpress (DE3) RP cells, and the protein was purified through affinity chromatography. The recombinant enzyme was characterised by pH optimum studies, and temperature optimum and stability experiments. The optimal reaction conditions for AL2 were pH 9.0 and 37 °C, while for the commercial enzyme, the optimal conditions were pH 8.0 and 37 °C. At optimal reaction conditions, the specific activity of AL2 was 151.6 ± 12.8 µmol h−1 mg−1 protein and 96.9 ± 13.1 µmol h−1 mg−1 protein for the commercial alginate lyase. Moreover, AL2 displayed impressive activity in breaking down alginate into AOS. Hence, AL2 shows potential for use as an industrial enzyme for the hydrolysis of alginate into alginate oligosaccharides. Additional studies should be carried out to further characterise this enzyme, improve its purity, and optimise its activity.

Alginate lyases have been widely used to prepare alginate oligosaccharides in food, agricultural, and medical industries. Therefore, discovering and characterizing novel alginate lyases with excellent properties has drawn increasing attention. Herein, a novel alginate lyase FsAlyPL6 of Polysaccharide Lyase (PL) 6 family is identified and biochemically characterized from Flammeovirga sp. NJ-04. It shows highest activity at 45 °C and could retain 50% of activity after being incubated at 45 °C for 1 h. The Thin-Layer Chromatography (TLC) and Electrospray Ionization Mass Spectrometry (ESI-MS) analysis indicates that FsAlyPL6 endolytically degrades alginate polysaccharide into oligosaccharides ranging from monosaccharides to pentasaccharides. In addition, the action pattern of the enzyme is also elucidated and the result suggests that FsAlyPL6 could recognize tetrasaccharide as the minimal substrate and cleave the glycosidic bonds between the subsites of −1 and +3. The research provides extended insights into the substrate recognition and degradation pattern of PL6 alginate lyases, which may further expand the application of alginate lyases.

Despite the progress in massive gene analysis of brown algal species, no alginate-degrading enzyme from brown alga has been identified, impeding the understanding of alginate metabolism in brown alga. In the current study, we identified and characterized alginate lyase from Saccharina japonica using a protein-based approach. First, cDNA library was prepared from the S. japonica sporophyte. Expression screening was then performed; the encoding gene was identified and cloned; and the recombinant enzyme was purified and characterized. Alginate lyase production in algal tissues was evaluated by western blotting. The identified alginate lyase, SjAly (359 amino acids, with a predicted N-terminal secretion signal of 27 residues), is encoded by an open reading frame comprising seven exons. Recombinant SjAly exhibited endolytic alginate lyase activity, specifically toward stretches of consecutive β-d-mannuronic acid units. The optimum temperature, pH, and NaCl concentration were 30 °C, pH 8.0, and 100 mM, respectively. SjAly exhibited pronounced activity below 20 °C, the S. japonica growth temperature. SjAly was highly expressed in the blade but not the stipe and rhizoid. The data indicate that S. japonica possesses at least one active alginate lyase. This is the first report of a functional alginate lyase from brown alga, the major natural alginate producer.

Alginate oligosaccharides (AOs) prepared through enzymatic reaction by diverse alginate lyases under relatively controllable and moderate conditions possess versatile biological activities. But widely used commercial alginate lyases are still rather rare due to their poor properties (e.g., lower activity, worse thermostability, ion tolerance, etc.). In this work, the alginate lyase Alyw208, derived from Vibrio sp. W2, was expressed in Yarrowia lipolytica of food grade and characterized in order to obtain an enzyme with excellent properties adapted to industrial requirements. Alyw208 classified into the polysaccharide lyase (PL) 7 family showed maximum activity at 35 °C and pH 10.0, indicating its cold-adapted and high-alkaline properties. Furthermore, Alyw208 preserved over 70% of the relative activity within the range of 10–55 °C, with a broader temperature range for the activity compared to other alginate-degrading enzymes with cold adaptation. Recombinant Alyw208 was significantly activated with 1.5 M NaCl to around 2.1 times relative activity. In addition, the endolytic Alyw208 was polyG-preferred, but identified as a bifunctional alginate lyase that could degrade both polyM and polyG effectively, releasing AOs with degrees of polymerization (DPs) of 2–6 and alginate monomers as the final products (that is, DPs 1–6). Alyw208 has been suggested with favorable properties to be a potent candidate for biotechnological and industrial applications.

Alginate oligosaccharides (AOs) are the degradation products of alginate, a natural polysaccharide abundant in brown algae. AOs generated by enzymatic hydrolysis have diverse bioactivities and show broad application potentials. AOs production via enzymolysis is now generally with sodium alginate as the raw material, which is chemically extracted from brown algae. In contrast, AOs production by direct degradation of brown algae is more advantageous on account of its cost reduction and is more eco-friendly. However, there have been only a few attempts reported in AOs production from direct degradation of brown algae.

Alginate lyases are important enzymes to prepare alginate oligosaccharides for industrial applications and elucidating the degradation pattern of alginate lyases is essential for expanding their applications. Herein, we cloned and expressed AlyPL6, a novel member of polysaccharide lyase family-6 (PL6) with high activity from Pedobacter hainanensis NJ-02. It was found that AlyPL6 could recognize tetrasaccharide as the minimal substrate to release oligosaccharides with low degrees of polymerization (DPs). As a result, it could be speculated that the cleavage site of substrate is located between -1 and +1 subsites. For further application, AlyPL6 was then immobilized onto mesoporous titanium oxide particles (MTOPs) with >55.4% of maximal activity retained at 45 °C after it was reused for 10 times. The research provided extended insights into the substrate recognition and degradation pattern of PL 6 alginate lyases, which may benefit the further application of alginate lyases a lot.Copyright © 2020 Elsevier B.V. All rights reserved.

Kelp contained laminarin, cellulose, and alginate as major polysaccharides and could be utilized as functional oligosaccharides. A new multifunctional glycoside hydrolase CelA was identified and characterized for the efficient degradation of kelp powder. It displayed cellulase (2308.38 U/mg), alginate lyase (578.68 U/mg), and laminarinase (720.97 U/mg) activities. It exhibited maximal activity on both sodium alginate and laminarin at 50 °C and pH 8.0, while it could degrade sodium carboxymethylcellulose (CMC-Na) by maximal activity at 40 °C and pH 7.0. The action mode analysis by thin layer chromatography and electrospray ionization mass spectrometry indicated that CelA adopted an endolytic manner to degrade CMC-Na, sodium alginate, and laminarin releasing oligosaccharides with degrees of polymerization (Dps) of 2-5. According to domain analysis, CelA contained a GH5 module and a PL6 module, and both of them exhibited glycoside hydrolase and polysaccharide lyase activity. The docking results revealed that Glu and Glu are essential in cellulose and laminarin degradation. As to the degradation of alginate, Asn, Lys, Arg, Asp, and Asn could bind alginate and Tyr and Lys acted as catalytic sites. CelA displayed high hydrolysis efficiency for cellulose, β-glucan, laminarin, alginate, and kelp powder. Thus, it has strong potential in food and feed industries as a catalyst for bioconversion of algal biomass into value-added products oligosaccharides.

Alginate lyase Aly448, a potential new member of the polysaccharide lyase (PL) 7 family, which was cloned and identified from the macroalgae-associated bacterial metagenomic library, showed bifunctionality. The molecular docking results revealed that Aly448 has two completely different binding sites for alginate (polyMG), poly-α-l-guluronic acid (polyG), and poly-β-d-mannuronic acid (polyM) substrates, respectively, which might be the molecular basis for the enzyme's bifunctionality. Truncational results confirmed that predicted key residues affected the bifunctionality of Aly448, but did not wholly explain. Besides, Aly448 presented excellent biochemical characteristics, such as higher thermal stability and pH tolerance. Degradation of polyMG, polyM, and polyG substrates by Aly448 produced tetrasaccharide (DP4), disaccharide (DP2), and galactose (DP1), which exhibited excellent antioxidant activity. These findings provide novel insights into the substrate recognition mechanism of bifunctional alginate lyases and pave a new path for the exploitation of natural antioxidant agents.

The enzymatic degradation of seaweed polysaccharides is gaining interest for its potential in the production of functional oligosaccharides and fermentable sugars. Herein, a novel alginate lyase, AlyRm3, was cloned from a marine strain, Rhodothermus marinus DSM 4252. The AlyRm3 showed optimal activity (37,315.08 U/mg) at 70 °C and pH 8.0, with the sodium alginate used as a substrate. Noticeably, AlyRm3 was stable at 65 °C and also exhibited 30% of maximal activity at 90 °C. These results indicated that AlyRm3 is a thermophilic alginate lyase that efficiently degrades alginate at high industrial temperatures (>60 °C). The FPLC and ESI−MS analyses suggested that AlyRm3 primarily released disaccharides and trisaccharides from the alginate, polyM, and polyG in an endolytic manner. In the saccharification process of sodium alginate (0.5%, w/v), the AlyRm3 yielded numerous reducing sugars (1.73 g/L) after 2 h of reaction. These results indicated that AlyRm3 has a high enzymatic capacity for saccharifying the alginate, and could be used to saccharify the alginate biomass before the main fermentation process for biofuels. These properties make AlyRm3 a valuable candidate for both fundamental research and industrial applications.

An outdoor experiment was performed for six months to evaluate the effects of organic fertilizers obtained from marine residual materials on strawberry plants. Three types of organic fertilizers were used, i.e., cod (Gadus morhua) bone powder, common ling (Molva molva) bone powder, and pellets obtained by mixing small cod bone powder and rockweed (Ascophyllum nodosum) residues. A tabletop system for strawberry cultivation was designed, in which two bare-root strawberry plants of cultivar ‘Albion’ were planted in a peat substrate in each pot. Five treatments were applied, i.e., cod bone powder (F1), common ling bone powder (F2), small cod bone powder and rockweed residue pellets (FA), chemical fertilizer (E), and a control (C). The number of leaves and their nutrient content, fruit yield and quality characteristics of the strawberries grown using the organic fertilizers were similar or better than those corresponding to treatments E and C. Organic fertilizers derived from the residues of fish and macroalgae could be a promising alternative to chemical fertilizers in strawberry production.

海藻提取物，特别是海藻寡糖，是使用现代技术从海藻中提取的天然活性物质，随着海藻寡糖在农业领域的应用不断深入，其研究取得了重大进展。为进一步系统了解和应用海藻寡糖，本文讨论了它们的来源、分类和生产方法，总结了海藻寡糖对增强作物抗逆性和抗病性、促进生长发育和改善养分吸收的影响，以及海藻寡糖在各种作物上的应用效果和作用机理。生物法降解海藻多糖是未来海藻寡糖制备的方向，现代生物法一般采用酶降解法，利用褐藻胶裂解酶将褐藻胶降解为褐藻寡糖或是利用琼胶裂解酶将琼胶降解为琼胶寡糖。海藻寡糖在农业中作为植物抗逆和抗病的诱导剂、生物刺激素和肥料增效添加剂使用，海藻寡糖通过调控植物基因表达、酶活性、激素合成和分配等方式增强农作物对干旱、低温、高盐渗透、重金属等胁迫因子的耐受性，并激发植物免疫，提高农作物抗病性。海藻寡糖对植物具有生物刺激作用，可调节植株生长发育，提高其对肥料的吸收效率，从而提升农作物产量和品质。海藻寡糖的应用对中国农业生产的绿色、高效、可持续发展具有积极意义，也有助于海洋资源的充分开发与利用。

Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from Bifurcaria bifurcata from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions. The elicitor capacities were evaluated by monitoring the activity of phenylalanine ammonia-lyase (PAL) as well as polyphenols content in the leaves located above the elicitation site for 5 days. Alginate and oligoalginates treatments triggered plant defense responses, which showed their capacity to significantly induce the PAL activity and phenolic compounds accumulation in the leaves of tomato seedlings. Elicitation by alginates and oligoalginates showed an intensive induction of PAL activity, increasing from 12 h of treatment and remaining at high levels throughout the period of treatment. The amount of polyphenols in the leaves was increased rapidly and strongly from 12 h of elicitation by both saccharide solutions, representing peaks value after 24 h of application. Oligoalginates exhibited an effective elicitor capacity in polyphenols accumulation compared to alginate polymers. The alginate and oligosaccharides derivatives revealed a similar elicitor capacity in PAL activity whereas the accumulation of phenolic compounds showed a differential effect. Polysaccharides extracted from the brown seaweed Bifurcaria bifurcate and oligosaccharides derivatives induced significantly the phenylpropanoid metabolism in tomato seedlings. These results contribute to the valorization of marine biomass as a potential bioresource for plant protection against phytopathogens in the context of eco-sustainable green technology.

<p class="MsoNormal"> <span> <p class="MsoNormal" style="text-align:justify;"> <span>Using phosphorus (P) fertilizers hashistorically increased agricultural productivity, yet the high</span>ly<span> dissipative nature of phosphate rock and the low efficiency due to soilfixation and runoff raise sustainability concerns.&nbsp; Algae fertilizers </span>have <span>emerge</span>d<span> as apromising eco-friendly alternative.&nbsp; </span>H<span>owever, thepotential of algae fertilizers for providing sus</span>tained P availability and their <span>impact</span>s on <span>plant</span> growth, <span>soil</span> microbes<span>,</span> and nutrient cycl<span>ing</span> remains to be explored.&nbsp; In this study, <span>wedeveloped a polyphosphate-enriched algae fertilizer (PEA)</span> <span>and</span> conducted comparative experimentswith chemical P fertilizers (CP) through soil and solution cultures, as well ascrop growth trials.&nbsp; Soil cultivationexperiments showed that <span>PEA release</span>d <span>twice</span> <span>as muchlabile P </span>as initiallyavailable<span> in </span>the <span>soil, </span>and it <span>function</span>ed<span> as aslow-release P source.&nbsp; In contrast,soils treated with</span> <span>CP initially exhibited high levels of labile P, </span>which<span> wasgradually converted to stable forms</span>, but it dropped <span>to</span> 30% <span>of the labile Plevel in PEA after three months.&nbsp; </span>Further tests<span> revealed that the slow release of P from PEA was linked toincreased microbial activity, </span>and the <span>microbial biomass P (MBP) content </span>was about eight times higher than insoils treated with<span> </span>CP after three months<span>,resulting in a</span> 75%<span> declin</span>e<span> in the microbial biomass carbon (MBC) to MBP ratio</span>.&nbsp;Microbial diversity analysis showed that algae fertilizers could<span> recruit more beneficial microbes</span> than CP, like phosphorus-solubilizingbacteria, plant growth-promoting bacteria,<span> and </span>stress-resistant bacteria.&nbsp; <span>Crop pot experiments</span>,<span> </span>along with <span>ampliconand metagenomic analysis of tomato root-associated microbes, revealed that </span>algae fertilizers including <span>PEA</span> promotedplant growth <span>com</span>parable to CP, and<span> enhance</span>d<span> soil P cycling and overall nutrient dynamics.&nbsp; </span>These data showed that algae fertilizers, especially PEA, can stabilizesoil P fertility and stimulate plant growth through their slow P release andthe recruitment of beneficial microbes.&nbsp;O<span>ur</span> study highlights the potential of <span>PEA</span> to foster sustainable agricultureby mitigating the P scarcity and soil P loss associated with chemicalfertilizers and improving plant growth and soil health. </p></span></p>

In swine farming, animals develop diseases that require the use of antibiotics. In-feed antibiotics as growth promoters have been banned due to the increasing concern of antimicrobial resistance. Seaweeds offer bioactive molecules with antibacterial and antioxidant properties. The aim was to estimate the in vitro properties of seaweed extracts: Ascophyllum nodosum (AN), Palmaria palmata (PP), Ulva lactuca (UL), and 1:1 mixes (ANPP, ANUL, PPUL). Escherichia coli strains were used to test for growth inhibitory activity, and chemical-based assays were performed for antioxidant properties. The treatments were 2 (with/without Escherichia coli) × 2 (F4 + and F18 +) × 5 doses (0, 1.44, 2.87, 5.75, 11.50, and 23.0 mg/mL). Bacteria were supplemented with seaweed extracts, and growth was monitored. The antioxidant activity was assessed with 6 doses (0, 1, 50, 100, 200, 500, and 600 mg/mL) × 6 compounds using two chemical assays. Data were evaluated through SAS. The results showed that AN and UL significantly inhibited (p < 0.05) the growth of F4 + and F18 +. PP and mixes did not display an inhibition of the bacteria growth. AN, PP, UL extracts, and mixes exhibited antioxidant activities, with AN showing the strongest dose-response. Thus, AN and UL seaweed extracts reveal promising antibacterial and antioxidant effects and may be candidates for in-feed additives.© 2024. The Author(s).

The aim of the research was to determine the antioxidant and antimicrobial activity, determination of chemical elements and heavy metals in seaweed extracts of wakame, arame, dulse, laminaria, kombu, and hijiki. Antioxidant activity was determined by DPPH method and the activity ranged from 0.00 to 2641.34 TEAC. The highest antioxidant activity was observed in kombu (2641.34 TEAC) and arame (2457.5 TEAC). Antimicrobial activity was analyzed by disk diffusion method and MIC method. Three G+ bacteria (Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis), three G- bacteria (Salmonella enterica, Pseudomonas aeruginosa, Yersinia enterocolitica), and four yeasts (Candida tropicalis, C. krusei, C. glabrata, C. albicans) were used as model organisms. The size of inhibition zones ranged from 0.00 to 8.67 mm. The minimum inhibitory concentrations of the selected seaweeds ranged from MIC50 98.46 (MIC90 100.25) to MIC50 3.43 µL/mL (MIC90 5.26 µL/mL). The content of selected elements was determined in seaweed samples by ICP-OES. The chemical composition of the algae showed differences between species and the presence of heavy metals. Arsenic, cadmium, and aluminum were confirmed. All seaweed samples contained arsenic ranging from 6.6546 to 76.48 mg/kg. Further investigation of seaweeds is needed to identify the active substances present in the algae that are responsible for antioxidant and antimicrobial activity. This study was carried out to evaluate the antimicrobial and antioxidant activity of extracts from five commonly consumed seaweeds for their ability to inhibit selected microorganisms and to determine the health risk due to heavy metals content. Our study contributes to the evidence that seaweeds have antimicrobial and antioxidant activity and seaweed extracts have for pharmacological applications.

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.© 2025. The Author(s).