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Algae, like other plants, produce a variety of remarkable compounds collectively referred to as secondary metabolites. They are synthesized by these organisms at the end of the growth phase and/or due to metabolic alterations induced by environmental stress conditions. Carotenoids, phenolic compounds, phycobiliprotein pigments, polysaccharides and...
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Cyanobacteria are specific group of photoautotrophs representing a potential source of various pigments such as phycobiliproteins, carotenoids and chlorophylls. These pigments are extensively used commercially in foods, cosmetics, biotechnology, pharmacology and medicine. Six cyanobacterial strains belonging to two genera (Desertifilum and Halolept...
Algae are morphologically diverse and widely distributed photosynthetic organism recognized as an excellent source of pigments including chlorophylls, carotenoids and phycobiliproteins. Algal pigments are in prime focus as they can be produced in large quantities in renewable manner. All these pigments are of great potential in biotechnological app...
Studies on various nitrogen fixing microalgal strains found in the rice paddy field soils are carried out in different parts of the world. In the present study two cyanobacterial strains belonging to the order nostocales, Calothrix sp. and Microchaete sp. were isolated from the rice fields of Karimganj district, South Assam, India and characterized...
Disposal of polythene into waste water poses a serious problem as they get accumulated in the environment. Submerged polythene in waste water offers an ideal substratum for algae to colonize. The present paper highlights the biochemical composition of five cyanobacteria isolated from submerged polythene surface in domestic sewage water, Silchar tow...
In the present study, several physiological responses of the red marine alga Porphyra haitanesis to elevated concentrations of copper (up to 50 μM) and zinc (up to 100 μM) were investigated. Our results showed that the effects of Cu2+ and Zn2+ on growth, photosynthetic pigments (chlorophylls and carotenoids), phycobiliprotein and metabolism (the fl...
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... Algae, a diverse group of simple organisms, play a crucial role in aquatic ecosystems. They contain chlorophyll-a (Chl-a) and are an essential part of the food web, contributing to oxygen production, nutrient removal from water, and sediment stabilization (Shalaby, 2011). However, algae can also limit sunlight penetration through water, creating hypoxic conditions that lead to ecosystem degradation and economic impacts on sectors such as water supply, fisheries, and tourism (Hafeez et al., 2019;Stauffer et al., 2019). ...
Remote sensing is a cost-effective method for monitoring chlorophyll-a (Chl-a) concentration, an indicator of eutrophication, due to its spatiotemporal effectiveness and availability of historical data. However, its application in shallow, small water bodies poses challenges due to the need for high spatial and temporal resolutions, significant optical interference from other water constituents, and depth-related accuracy issues. This study assessed the performance of Landsat-8 and Sentinel-2 satellites in estimating Chl-a concentrations in Chitgar Lake, Tehran. Semi-empirical models, constructed with 73 and 122 common data pairs between observed data and Landsat-8 and Sentinel-2 reflectance data, respectively, yielded accurate estimates. Two Band (2BAND) algorithm (green and red band ratio, R2=0.8, RMSE (root mean square error) =1.12 µg.L-1 and NRMSE (normalized root mean square error) =12.4%) was identified as the best Landsat-8 based model. Both Normalized Difference Chlorophyll Index (NDCI) algorithm (red and red edge bands composition, R2=0.82, RMSE=1.29 µg.L-1, NRMSE=7.8%) and 2BAND algorithm (red and red edge band ratio, R2=0.81, RMSE=1.28 µg.L-1, and NRMSE=7.7%) were the best models for Sentinel-2 data, with a Power of 0.8. Overall, remote sensing data from both satellites demonstrated appropriate performance and can accurately estimate Chl-a concentrations in Chitgar Lake as a shallow freshwater body.
... In brown algae (Phaeophyceae), phenolic compounds are referred to as phlorotannins, which are phloroglucinol (1,3,5-trihydroxybenzene) units with different polymerization degrees [9]. Depending on the algal species, phlorotannin content can reach up to 25-30% DW and provide interesting biological functions as antimicrobial, antioxidant or photoprotective activities [7,[10][11][12][13][14][15][16], and then can be used for various applications. ...
Brown seaweeds are attracting attention due to their richness in bioactive compounds, in particular, their phlorotannins. We present here a case study of two Fucales, Ascophyllum nodosum and Halidrys siliquosa, sustainably collected, to produce active polyphenols for the cosmetics sector. Phenolic contents of crude extracts, obtained by Accelerated Solvent Extraction (ASE), were more elevated in H. siliquosa at 100.05 mg/g dry weight (DW) than in A. nodosum (29.51 mg/g DW), considering 3 cycles with cell inversion. The temperature of extraction for a high phenolic content and high associated antioxidant activities close to positive controls was 150 °C for both algae and the use of only one cycle was enough. A semi-purification process using Solid-phase Extraction (SPE) was carried out on both ASE crude extracts (one per species). The majority of phlorotannins were found in the ethanolic SPE fraction for A. nodosum and the hydroethanolic one for H. siliquosa. The SPE process allowed us to obtain more concentrated fractions of active phenolic compounds (×1.8 and 2 in A. nodosum and H. siliquosa, respectively). Results are discussed in regard to the exploitation of seaweeds in Brittany and to the research of sustainable processes to produce active natural ingredients for cosmetics.
... vegetable oils (edible and non-edible), animal fats and waste cooking oils (used oil). Lately, algae oils have been gaining interest given their high oil content and rapid biomass production (Karmakar et al. 2010;Baig et al. 2018;Shalaby 2011;Paul Abishek et al. 2014). The use of edible oils in the production of biocomponents has an impact on the global imbalance between market demand and food supply through their high prices, reduced food sources and increased capacity of commercial plants. ...
Intensive research is currently being carried out worldwide to replace fossil raw materials with renewable ones or waste based on chemical synthesis. However, it is important that the newly developed raw materials do not conflict with global food production and recommend the use of non-edible or waste raw materials. Therefore, modified non-edible oilseed radish oil was used in the synthesis of polymeric materials. The functionalization of the oil was achieved through one-step, solvent-free transesterification process with triethanolamine, diethylene glycol, polypropylene glycol, ethylene glycol and propylene glycol. Biopolyols with hydroxyl numbers in the range of 237–346 mg KOH/g and different chemical structures were obtained. Open-cell polyurethane foams were produced by replacing 100% of the original petrochemical polyol with the biopolyols. The influence of the chemical structures of the biopolyols on the properties of the thermal insulation materials was analysed. The foams were characterised by low apparent densities of about 16 kg/m³. The type of biopolyol did not have a significant influence on the mechanical strength of the foams. A thermal analysis of the polyurethane biofoams was also carried out.
Graphical Abstract
... The presence of flavonoids in the experimental algae may be useful as an antioxidant agent as well as an antimicrobial agent. Shalaby (2011) [38] reported the presence of anthraquinones from an ethyl acetate fraction of Acanthophora spicifera. In the present study, the anthraquinones content was found in trace amounts (<4.15 ± 0.02 mg/g dry wt.) in the experimental algae Colpomenia sinuosa and Halymenia porphyroides. ...
Seaweeds are marine macroscopic algae which are considered as the important living marine organisms with high nutritive value and rich bioactive compounds present in the ocean. In the current study the phytochemical, amino acid, fatty acid and vitamin profile analysis of the seaweeds were conducted which were collected along the south east coast of India. The marine brown macro alga Colpomenia sinuosa (Mertens ex Roth) Derbes and Solier as well as the marine red alga Halymenia poryphyroides Boergesen were used in this study. The relationship between the nutritive components and the variation between phytochemical, amino acid, fatty acid and vitamin profile were mainly analyzed in the current study. The present analysis revealed that phytochemical contents like alkaloids, triterpenoids, steroids and glycosides were present in higher amounts in marine red alga Halymenia porphyroides compared to the marine brown alga Colpomenia sinuosa. Similarly the amino acid analysis showed higher percentage in marine red alga Halymenia porphyroides when compared to the marine brown alga Colpomenia sinuosa. The fatty acid profile also revealed higher content in Halymenia porphyroides when compared to Colpomenia sinuosa. On the contrary the vitamin profile analysis revealed higher amounts of vitamins content in Colpomenia sinuosa rather than Halymenia porphyroides. The presence of high phytochemical, amino acid, fatty acid constituents in Halymenia porphyroides makes this seaweed more important when compared Colpomenia sinuosa which were rich in vitamin content and can be used as an important vitamin source for human and animal diet.
... This includes optimizing strain selection through genetic and metabolic engineering to maximize the production of bioactive products. It's also crucial to study how well the body absorbs and uses these compounds in functional foods and supplements [33,34]. Generally, Algae are recognized as a rich source of nutrition, containing proteins, dietary fibers, vitamins, minerals, and essential fatty acids [35,36]. ...
The aim of the present study was to identify and quantify the biochemical profile of Vaucheria karachiensis and to evaluate its nutritional, antioxidant, antimicrobial and hypoglycemic potential. The study revealed ash content of 34.98 %, followed by carbohydrates (20.37 %), crude protein (18.74 %), moisture (12.12 %), crude fat (11.20 %), crude fiber (2.59 %) and total energy (122.75 Kcal/100 g). 15 compounds were identified through GC–MS in ethyl acetate extract with major compounds being Pentadecanoic acid, 14-methyl-, methyl ester (31.62 %), Methyl stearate (13.36 %), 9-Octadecenoic acid, methyl ester, (E)- (11.46 %), n-Hexadecanoic acid (7.47 %), Phytol (6.31 %), 9,12-Octadecadienoic acid, methyl ester, (E, E)- (5.64 %), and 1-Octadecyne (5.34 %). Whereas 24 compounds were tentatively detected in n-butanol extract with major compounds being Hexadecanoic acid, butyl ester (44.63 %), followed by Phytol (11.49 %), Hexadecanoic acid, methyl ester (8.33 %), and 9-Hexadecenoic acid (7.31 %). FT-IR spectroscopy confirmed the presence of hydroxyl groups, alcohols, carboxylic acids, carbonyl groups, and aromatic compounds. Moreover, ethyl acetate extract exhibited higher total phenolics (1.743 ± 0.43 mg GAE/g) and total flavonoid content (2.213 ± 0.83 mg QE/g). Ethyl acetate extract demonstrated slightly better radical-scavenging activity (IC50 62.78 ± 3.23) than n-butanol extract i.e. (IC50 63.73 ± 5.46). Significant antimicrobial activity was observed by both extracts against tested bacterial and fungal strains. Furthermore, both extracts showed potential hypoglycemic activity in a diabetic animal model, with ethyl acetate extract exhibiting more pronounced effects in lowering blood glucose levels after 24 h of drug administration (262.50 ± 4.85, 239.50 ± 2.74, and 229.17 ± 3.87) at doses of 100 mg/kg, 200 mg/kg, and 300 mg/kg, respectively. The findings suggest that V. karachiensis possesses valuable nutritional and bioactive components, highlighting its potential as a functional ingredient in various applications, including food, pharmaceuticals, and nutraceuticals.
... Compounds derived from cyanobacteria have been routinely used for medicinal purposes since time immemorial (Shalaby, 2011). Several biological properties of algae-derived chemical compounds are adequately reported (Alves et al., 2018;Bhatia et al., 2015;Kar et al., 2022;Wells et al., 2017). ...
... Phytoplankton are the plant-like organisms that are found in aquatic habitats, as a producer which serves as food for zooplankton in a food chain. As photosynthetic organisms, these groups play a key role in productivity of the water (Shalaby, 2011). They are also a major source of organic carbon and may represent an important source of oxygen in aquatic ecosystem (Adadu et al., 2018). ...
Ephemeral waters, the temporary aquatic environment become an interesting habitat to explore extremophile organism, include phytoplankton. Furthermore, the waters have an acidic condition or low pH that impact to metabolisms, community structure, and diversity of phytoplankton. This study was conducted on June until August 2022 in Bangka Regency, Bangka Belitung Archipelago Province, Indonesia. We analyzed the phytoplankton presence at acidic ephemeral waters to indicated their potential as primary producer in food web, bioindicator, and ecological succession agent. This study was conducted by exploration method of phytoplankton diversity. The research observed and found five class and twelve genera that consist of class Chlorophyceae (genera Enteromorpha, Ankistrodesmus, Prasiola, Pleurococcus, and Coleochaete), class Rhodophyceae (genera Lemanea), class Diatoms (genera Diatoma, Synedra, and Navicula), class Xanthophyceae (genera Ophiocytium), and class Cyanobacteria (genera Oscillatoria and Anabaena). The class Chlorophyceae, genera Enteromorpha were the highest community at the both of acidic waters and they could survive at pH 3.52 + 0.5 to 3.71 + 0.8.AbstrakPerairan ephemeral, lingkungan perairan musiman menjadi suatu habitat yang menarik untuk mengeksplorasi organisme ekstremofil, termasuk fitoplankton. Lebih jauh lagi, perairan tersebut memiliki kondisi asam atau pH rendah yang berdampak pada metabolisme, struktur komunitas, dan diversitas fitoplankton. Penelitian ini dilaksanakan pada Juni hingga Agustus 2022 di Kabupaten Bangka, Provinsi Kepulauan Bangka Belitung, Indonesia. Kami menganalisis keberadaan fitoplankton di perairan ephemeral asam untuk mengindikasikan potensi fitoplankton sebagai produsen utama, bioindikator dan agen suksesi lingkungan. Penelitian ini dilaksanakan dengan metode eksplorasi diversitas fitoplankton. Penelitian ini mengobservasi dan menemukan lima kelas dan dua belas genus yang terdiri atas kelas Chlorophyceae (genus Enteromorpha, Ankistrodesmus, Prasiola, Pleurococcus, dan Coleochaete), kelas Rhodophyceae (genus Lemanea), kelas Diatoms (genus Diatoma, Synedra, dan Navicula), kelas Xanthophyceae (genus Ophiocytium), dan kelas Cyanobacteria (genus Oscillatoria dan Anabaena). Kelas Chlorophyceae, genus Enteromorpha adalah komunitas tertinggi pada kedua perairan asam dan mampu bertahan pada pH 3.52 + 0.5 to 3.71 + 0.8.
... Allelopathic compounds released from macroalgae (such as lipid metabolites) have been shown to adversely affect corals through direct contact with coral surfaces, often leading to bleaching (Rasher & Hay, 2010;Rasher et al., 2011). Their release during photosynthesis (Paul & Ritson-Williams, 2008;Shalaby, 2011) can also indirectly affect corals by acting as a substrate to microbial communities and thereby influencing their growth and functioning. Macroalgae are efficient consumers of CO 2 maintaining high pH in the water column during the day (Smith et al., 2013). ...
Coral reefs are subject to degradation by multiple environmental stressors which are predicted to intensify. Stress can alter ecosystem composition, with shifts from hard coral to macroalgae dominated reefs often accompanied by an increase in soft corals and sponges. Such changes may alter net ecosystem metabolism and biogeochemistry by shifting the balance between photosynthesis, respiration, calcification and dissolution. We deployed high temporal resolution pH and dissolved oxygen (DO) sensors at four Caribbean reef sites with varying covers of hard and soft corals, sponges and macroalgae. The resultant data indicated that the strength of the “metabolic pulse”, specifically the co‐variation in daily pH and DO oscillations, was driven by the net balance of light ‐dependent and ‐independent metabolism. pH and DO were positively correlated over the diel cycle at coral dominated sites, suggesting that photosynthesis and respiration were the major controlling processes, and further indicated by agreement with a simple production:respiration model. Whereas, at a site with high macroalgal cover, pH and DO decoupling was observed during daylight hours. This indicates that an unidentified light‐driven process altered the expected pH:DO relationship. We hypothesize that this could be mediated by the higher levels of macroalgae, which either stimulated bacterial‐mediated carbonate dissolution via the production and release of allelopathic compounds or retained oxygen, evolved during photosynthesis, in the gaseous form in seawater (ebullition). Our work demonstrates that high resolution monitoring of pH and DO provides insight into coral reef biogeochemical functioning and can be key for understanding long‐term changes in coral reef metabolism.
... Seaweeds are emerging as a viable and plentiful source of natural bioactive compounds such as polyphenols, flavonoids, carotenoids, alkaloids, terpenes, tocopherols, polysaccharides, and peptides (Jacobsen et al., 2019), which have many pharmacological and biological activities and also have bioremediation potential (Shalaby, 2011). Polyphenols represent diverse compounds, including flavonoids (e.g., flavones, flavonols, flavanones, flavononols, chalcones, and flavan-3-ols), lignins, tocopherols, tannins and phenolic acids (Cox et al., 2010). ...
The effects of extracting solvents on the antioxidant and antibacterial activity of crude extracts of six seaweeds were investigated. The antioxidant activity of seaweed crude extracts was evaluated by total antioxidant activity (TAA), 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt (ABTS), and cupric reducing antioxidant capacity (CUPRAC) assays. Acetone extract of B. wrightii showed significantly (P < 0.05) the highest total phenolic content (TPC) (71.09 mg GAE/g), while methanolic extract of Porphyra sp. had the highest total flavonoid content (75.61 mg QE/g). Methanolic extract of S. muticum showed significantly (P < 0.05) the highest TAA. Methanolic extract of P. tetrastromatica and S. muticum showed significantly (P < 0.05) the highest DPPH and ABTS radical scavenging effects, while acetone extract of B. wrightii showed significantly the highest ECA0.50 value (0.78 mg/ml) of CUPRAC activity. Pearson's correlation test and principal component analysis (PCA) confirmed the relationship between TPC and various antioxidant activity assays of seaweed extracts. Methanolic extracts of P. tetrastromatica, S. muticum and H. clathratus showed higher inhibitory zones against all the bacterial strains than other seaweed extracts. The results of this study indicated that brown seaweeds showed comparatively better antioxidant and antibacterial activity, which could be utilized in the food processing industries.
... These compounds have a broad range of biological activities such as anticancer activity, antioxidant activity, and antimicrobial activity against fungi, bacteria, algae, viruses, and algae. Algae may also be utilized as organic fertilizer, or for bioremediation purposes [65]. They are high in nitrogen, phosphate, and potassium, due to which they have been utilized as a natural fertilizer in many coastal locations for centuries. ...
The fast depletion of fossil fuel reserves (coal, oil, natural gas) with an increase in environmental pollution has enforced the need for an alternate source of energy. A novel sustainable approach with the implementation of a zero waste discharge policy is an urgent need of the hour. Organic wastes with a higher fraction of biodegradable components can be considered an ideal source for sustainable bioenergy production. Biogas with a calorific value of 21–25 MJ/m³, produced by anaerobic digestion (AD) of organic waste, is considered an excellent replacement for fossil-derived fuels and natural gas while reducing more than 80% of greenhouse gases (GHGs) emissions to the environment. However, reduction in the rate of biomass hydrolysis and methane formation due to the accumulation of ammonia are some of the major limitations of the process that impede its industrial applicability. Recently, the performance of AD and methane production are improved with the usage of nanoparticles owing to their unique physical and chemical properties. In view of this, the present review summarizes various reports on nanotechnological advancement in biogas production while highlighting the knowledge gaps. The incorporation of nanoparticles in AD aids in the enhancement of biogas yield, increment in methane content, improvement of effluent quality, and reduction in H2S production. These nanoparticles act as the supplier of essential nutrients for the synthesis of enzymes and co-factors in anaerobic microorganisms which further stimulate their activity for higher biogas yield. Further, the mechanism of nanoparticle interaction during the AD process is elaborated.
Graphical Abstract
