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Chlorellin, an antibacterial substance from Chlorella
... [1][2][3][4][5][6] Some of the most remarkable metabolites of microalgae are substances that exhibit antibacterial properties-protein hydrolysates and lipid-type substances. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Peptide fractions of microalgae Chlorella sorokiniana, Saccharina longicruris, Nannochloropsis sp. had antibacterial activity against Grampositive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. [10][11][12] The maximum antibacterial effect against these bacteria was elicited with a peptide fraction with a mass <10 kDa obtained by hydrolysis of proteins with pepsin. ...
... Lipids of phototrophic microorganisms also exhibit antibacterial properties. [16][17][18][19][20][21][22][23] R. Pratt was among the first to investigate the antibacterial properties of lipid metabolites of microalgae. 17 According to that research, Chlorella vulgaris extracts inhibited the growth of Gram-positive and Gram-negative microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli and Pseudomonas pyocyanea (Ps. ...
... [16][17][18][19][20][21][22][23] R. Pratt was among the first to investigate the antibacterial properties of lipid metabolites of microalgae. 17 According to that research, Chlorella vulgaris extracts inhibited the growth of Gram-positive and Gram-negative microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Bacillus subtilis, Escherichia coli and Pseudomonas pyocyanea (Ps. aeruginosa). ...
Microalgae metabolites exhibit significant biological activity and can act as antibacterial agents (peptide and lipid fraction) against Gram-positive bacteria Bacillus and as a component of nutrient media in the cultivation of yeast Saccharomyces cerevisiae. In this study, a mixture of metabolites (triacylglycerides, fatty acids, o-dialkylmonoglycerides and glycerol trialkyl esters) extracted from disrupted Chlorella sorokiniana microalgae cells by non-polar solvent had inhibitory effect on the growth of Gram-positive bacteria at photosynthetically active radiation (PAR) levels of 100 ± 6 μmol photons/(m2·s). The minimum inhibitory concentration (MIC) of the extract was ≈80 μg/mL. Out of the isolated components of the mixture, triacylglycerides and fatty acids showed antibacterial properties, with MIC = 176 μg/mL and MIC = 445 μg/mL respectively. The water-soluble peptide fraction extracted from microalgae cells had an inhibitory effect on the growth of Gram-positive bacteria Bacillus both under white light illumination and in the dark; MIC of the peptide fraction is ≈125 μg/mL (when illuminated) and 170 μg/mL (in the dark). The water-soluble protein fraction had no antibiotic properties, but is of interest as a component of nutrient medium (0.01 mL/mL) for the cultivation of yeast Saccharomyces cerevisiae. The addition of this fraction allowed a 21% increase in population capacity compared with the control sample, a 1.4-fold increase in the specific growth rate in the exponential phase and a 28% decrease in cell generation time. The study has contributed to establishing the effect of light radiation on antibacterial properties of microalgae metabolites and identifying the minimal inhibitory concentration with regard to Gram-positive bacteria. Also, the potential of the Chlorella aqueous extract to serve as a component of nutrient media for the Saccharomyces cerevisiae cultivation has been researched.
... Since the pioneering work of Pratt et al. (1944) demonstrated the activity of green alga Chlorella against several Gram-positive and Gram-negative bacteria and isolated the first antibacterial compound chlorellin from this species, the interest for mining important natural compounds from these organisms is rising. Numerous studies followed suit to detect compounds from these organisms, and large screening programs were conducted to assess the potential of microalgae and cyanobacterial extracts for bioactivity (Corona et al. 2017;Patel et al. 2015;). ...
... Based on the number of screening processes performed, many bioactive compounds from microalgae were reported with pharmaceutical applications with antifungal, antibacterial, anticancer, antiviral, anti-inflammatory, antitumoral, and antioxidant activity . Important bioactive compounds reported from microalgae and cyanobacteria are cyanovirin-N, a virucidal compound isolated from Nostoc ellipsosporum (Colleluori et al. 2005), antimicrobial and anticancer compound borophycin from Nostoc linckia (Hemscheidt et al. 1994), antimicrobial compounds eicosapentaenoic acid from Phaeodactylum tricornutum, and α-linolenic acid from Chloroccocum HS-101 (Desbois et al. 2009;Ohta et al. 1993;Pratt et al. 1944). Apart from the antimicrobial nature of compounds isolated from microalgae and cyanobacteria, several other bioactive compounds from these organisms exhibit different types of biological activity. ...
... Chlorellin is the first antibiotic compound reported from microalgae. It is a mixture of fatty acids from the green microalgae Chlorella sp., and it was shown to have antibacterial activity against various Gram-positive (G+) and Gram-negative (GÀ) bacteria (Pratt et al. 1944). Further studies have also identified compounds belonging to fatty acids, polysaccharides, polyphenols, pigments, alkaloids, and peptides that inhibit the growth of many human pathogens (Syed et al. 2015;Dewi et al. 2018). ...
Carotenoids are pigments having a proven role as food colorants, antioxidants, health-promoting substances, food additives, feed additives, vitamins, pharmaceuticals, etc. After experiencing the hazard of synthetic entities in human life, people are again trying to “go natural.” Being natural and part of a healthy ecosystem, microalgae may have immense potential to provide many such entities. In the present scenario, microalgal systems are among the top-ranked bioresources to meet the demands of the fast-growing world population. In addition, being grown in natural water resources provides opportunities to socially backward classes to manage their lifestyle for economic upliftment and nutritional well-being. Carotenoids may be divided into primary and secondary groups. The secondary carotenoids are present in the lipid vesicles in the cytosol or plastids. Also, phycobiliproteins, phycocyanin, phycoerythrins, β-carotenes, lutins, and astaxanthins are the pigments which are commonly produced by microalgae. Many microalgal systems have been investigated so far to produce different pigments, for instance, diatoms and members of Phaeophyceae for fucoxanthins, dinoflagellates for peridinin, cryptophytes for alloxanthins, Porphyridium spp. for β-carotenes, Tetraselmis spp. for lutein, and so on. This chapter aims to provide an overview of the potential of microalgal systems to generate valuable carotenoids and pigments.
... [71]. Chlorella sp. have been identified as producers of a potent antibacterial compound known as "Chlorellin" [72,73]. Such bioactive compounds are assumed to exhibit robust antibacterial properties, which could serve as an effective defense mechanism against pathogenic bacteria [31,[71][72][73]. ...
... Chlorella sp. have been identified as producers of a potent antibacterial compound known as "Chlorellin" [72,73]. Such bioactive compounds are assumed to exhibit robust antibacterial properties, which could serve as an effective defense mechanism against pathogenic bacteria [31,[71][72][73]. ...
The cocultivation of microalgae in aquaponic systems can improve nutrient removal and enhance water quality. Moreover, it can promote the biological and physicochemical balance in aquaponic ecosystems. However, the bacterial communities in aquaponic systems have not yet been comprehensively characterized and the effects of microalgae cocultivation remain unclear. Using 16S rRNA gene sequencing, we sought to elucidate the effects of a cocultivation of Chlorella vulgaris, Scenedesmus species, and Spirulina platensis cocultivation on the bacterial communities in the rearing tanks and the biofilter of a garlic (Allium sativum L.) and Nile tilapia (Oreochromis niloticus L.) aquaponic system during a 56-days experiment. Feed intake, weight gain, and survival rates of Nile tilapia significantly improved in experimental groups cocultivated with microalgae compared to the control group, while garlic plant biomass, leaf number, and shoot length were not significantly different from the control. Alpha-diversity analysis revealed significantly higher richness and evenness in the bacterial communities from the biofilter and rearing tanks of the cocultivated systems when compared with the control system. The cocultivation also had a statistically significant effect on the bacterial composition: nonmetric multidimensional scaling analysis of a Bray–Curtis dissimilarity matrix demonstrated unique clustering patterns, indicating distinct bacterial communities in the biofilter and rearing tank water cocultivated with microalgal strains. We found significantly decreased abundances of the potentially pathogenic bacterial genera Janthinobacterium, Aeromonas, Pseudomonas, and Flavobacterium in aquaponic systems cocultivated with microalgae when compared to the control. Furthermore, the beneficial bacterial genera Fusibacter, Geothrix, Thiobaca, and Treponema were significantly enriched in the microalgae cocultivated systems. The results clearly demonstrate that integrating microalgae into an aquaponic recirculating aquaculture system (RAS), not only improves weight gain and survival rates of Nile tilapia, but also enriches beneficial bacterial genera and reduces potentially pathogenic microorganisms, offering a promising strategy to reduce antibiotic use and enhance water quality in aquaponics, without growth impairments of cocultivated plants.
... Chlorella contains a significant component, the Chlorella growth factor (CGF), a complex mixture of substances including peptides, nucleic acids, vitamins and minerals . These compounds exhibit a wide range of effects, including antibacterial (Pratt et al., 1944), antifungal (Sarkar et al., 2021), antiviral (Ibusuki et al., 1990), antitumor (Hasegawa et al., 2002), anti-oxidative, anti-inflammatory (Vijayavel et al., 2007) and immunomodulatory properties (Halperin et al., 2003;Pradhan et al., 2023). Research findings have indicated that organic extracts derived from Chlorella display substantial anti-proliferative activity against the MCF-7 breast cancer cell line. ...
... The present study confirms that C. vulgaris possesses antibacterial properties, not only in its crude form but also in individual organic fractions. Previous studies have indicated that the Chlorellin pigments found in the algae exhibit activity against certain bacteria, as per the findings of Pratt et al. (1944) and Matusiak et al. (1965). In addition, the analysis of Chlorella sp. ...
The ethanol-based crude extract and fractions partially purified from the freshwater microalga, Chlorella vulgaris underwent screening using disc diffusion assays. The tube dilution method was also employed to determine the minimum inhibitory concentration (MIC) values. The screening involved testing a variety of Gram negative bacterial fish and shellfishpathogens. The panel of pathogens included four strains of Aeromonas hydrophila (AH1, AH2, AH3, AH4), two strains of Pseudomonas putida (PP1, PP2), two strains of Pseudomonas aeruginosa (PA1, PA2), two strains of Pseudomonas fluorescens (PF1, PF2), Escherichia coli (O115, O1, O156, O164, O111 and O109), Vibrio alginolyticus (VA), V. anguillarum (VAN), V. fluvialis (VF), V. parahaemolyticus (VP), V. harveyi (VH), V. fisheri (VFS), and Edwardsiella tarda.The crude ethanolic extract underwent partial purification through silica gel column chromatography.The crude ethanolic extract was potentially active against all the selected bacterial pathogens, with the lowest MIC value (300 μg) against P. aeruginosa (PA2) and E. coli (O1, O156, O109). Among the nine chromatographic fractions, three exhibited higher activity with lower MIC values (40-50 μg). The results indicate that partially purified C. vulgaris extract has superior antibacterial activity compared to the crude extract. It could be a viable alternative for managing bacterial pathogens in aquaculture, potentially curbing the rise of antibiotic resistance. Keywords: Antibacterial, Chlorella vulgaris, Minimum inhibitory concentration, Pathogen, Vibrio
... The pharmaceutical industry has discovered new bioactive compounds, such as antiviral agents, that have helped in treating many diseases in the past few years. Many bioactive compounds have been discovered from algae-like fucoidans, lectins, polysaccharides, proteins, pigments, and polyphenols [64,65] (Table 1). Galactan isolated from red algae, Callophyllis variegate, Agardhiella tenera, Schizymenia binderi, and Cryptonemia crenulata has shown significant antiviral activity towards Herpes simplex virus (HSV-1, HSV-2), Human immunodeficiency virus, Dengue and Hepatitis A virus. ...
... Scientists have investigated that fatty acids are responsible for the antimicrobial activities of the microalgae. Antimicrobial/antibacterial activity entices cell death of microbial/bacterial protoplasts, which constitutes saturated and unsaturated long-chain fatty acids having more than ten carbon atoms [64]. The first isolated antibacterial substance from Chlorella (microalgae), named chlorellin, had antibacterial activity against gram-negative and gram-positive bacteria [78]. ...
Algae is emerging as a bioresource with high biological potential. Various algal strains have been used in traditional medicines and human diets worldwide. They are a rich source of bioactive compounds like ascorbic acid, riboflavin, pantothenate, biotin, folic acid, nicotinic acid, phycocyanins, gamma-linolenic acid (GLA), adrenic acid (ARA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), etc. Beta-carotene, astaxanthin, and phycobiliproteins are different classes of pigments that are found in algae. They possess antioxidant, anti-inflammatory and anticancer properties. The sulfur-coated polysaccharides in algae have been used as an anticancer, antibacterial, and antiviral agent. Scientists have exploited algal-derived bioactive compounds for developing lead molecules against several diseases. Due to the surge in research on bioactive molecules from algae, industries have started showing interest in the large-scale production of bioactive compounds having applications in sectors like pharmaceuticals, food, and beverage. In the food industry, algae are used as a thickening, gelling, and stabilizing agent. Due to their gelling and thickening characteristics, the most valuable algae products are macro-algal polysaccharides, such as agar, alginates, and carrageenan. The high protein, lipid, and nutrient content in microalgae makes it a superfood for aquaculture. The present review aims to describe various non-energy-based algae applications in pharmaceuticals, food and beverage, cosmetics, and nutraceuticals. This review attempts to analyze information on algal-derived drugs that have shown better potential and reached clinical trials.
... Molecules that perform antibiotic activities were isolated from microalgae for the first time by Pratt et al., in 1944. They isolated a fatty acid mixture from chlorella, which showed antibacterial and anti-autotoxic functions [43]. ...
... Fucoxanthin was found to perform activities against Staphylococcus epidermidis, Staphylococcus aureus, and Streptococcus agalactiae, but it did not perform a bacteriostatic activity against strict anaerobic bacteria [44]. Sudomova et al., found that fucoxanthin exerted antibacterial effects on mycobacterium tuberculosis by inhibiting the UDP-galactopyranose mutase and arylamine-N-acetyltransferase activities, demonstrating the great potential of fucoxanthin for the treatment of tuberculosis [45]. Salvatore et al., studied two species of black sea algae, Polysiphonia denudota and P. denudataf fragilis, and found that they performed antibacterial activities, strongly [46]. ...
Microalgae are a kind of photoautotrophic microorganism, which are small, fast in their growth rate, and widely distributed in seawater and freshwater. They have strong adaptability to diverse environmental conditions and contain various nutrients. Many scholars have suggested that microalgae can be considered as a new food source, which should be developed extensively. More importantly, in addition to containing nutrients, microalgae are able to produce a great number of active compounds such as long-chain unsaturated fatty acids, pigments, alkaloids, astaxanthin, fucoidan, etc. Many of these compounds have been proven to possess very important physiological functions such as anti-oxidation, anti-inflammation, anti-tumor functions, regulation of the metabolism, etc. This article aimed to review the physiological functions and benefits of the main microalgae-derived bioactive molecules with their physiological effects.
... In addition, brown algae Fucoidan is used as a bacterial inhibitor because it contains many chemical functional groups, such as fatty acids, polysaccharides, sterols, aromatic organic acids, polyketides, alcohols, ketones, halogenated furanones, phlorotannin, peptides, polyacetylenes, terpenes, indole alkaloids, shikimic acid, hydroquinone, and aldehydes [174]. Polysaccharides such as Fucoidan and laminarin have antibacterial activity due to glycoprotein receptors on their cell surface, which bind to compounds in the cytoplasmic membrane, DNA, and bacterial cell wall, resulting in increased cytoplasmic membrane permeability, protein leakage, and bacterial DNA binding [175,176]. In disck diffusion assays [177], showed that polysaccharides extracted from brown algae (Dictyopteris membranacea) and red algae (Pterocladia capillacea) in cold and hot water prevented the growth of Gram-positive Staphylococcus aureus and Bacillus cereus, as well as Gram-negative E. coli and Pseudomonas fluorescens. ...
... According to Amaro et al. [16] and Morois et al., (2015), the bioactive compound and metabolites produced by microalgae subsequently accumulate in growing media which have been proven to have antimicrobial, anti-fungal and antiviral properties [16,17 and 18]. According to Pratt et al. [19] the first antimicrobial compound isolated from metabolites of chlorella algae which was having antimicrobial activities against both Gram-negative and Gram-positive bacterial species. According to Ohta et al., [20] metabolic extracts of chrococcum stem HS-101 and Dunalialla primolouta had great antibacterial activities against methanocillin-resistant Stap. ...
Blue-green algae (cyanobacteria) are considered the most primitive photosynthetic prokaryotes which appeared on this planet during the Precambrian period. The application of cyanobacteria showed immense potential in wastewater and industrial effluent treatment, bioremediation of aquatic and terrestrial habitats, chemical industries, biofertilizers, food, feed, and fuel, etc. Spanish local fishermen collected blue-green masses from the lakes that were prepared as a dry cake, known as 'tecuitlatl'. Spirulina, chlorella and Noctoc cyanobacterial species are being used as food supplements which are full of nutrients such as protein, and vitamins, and also have medicinal values like antiviral, antibacterial, anti-cancerous ECT. Besides, several Cyanobacterial species are also being used as biofertilizers in agriculture, and also for chelating toxic heavy metal ions for removing them from soil which is commonly known as bioremediation of soil pollutants. In viewing the "one platform" solution, nature has provided for all the environmental and medical problems in Cyanobacteria, there is a need to practically implement the use of cyanobacteria in the lives of common man. This chapter not only shades lite on the nutritional but also medicinal values of different species of cyanobacteria but also briefly discussed the new discovery of Exo-polysaccharides (metabolites) of cyanobacteria which are considered as one of the important group of biopolymers having significant ecological, industrial and biotechnological importance. Due to their structural complexity, versatility and valuable biological properties, they are now emerging as high-value compounds. However, poor understanding of their complex structural properties, and lack of concrete information regarding the genes encoding the proteins involved in the EPS biosynthetic pathways, their process of Research Perspectives of Microbiology and Biotechnology Vol. 4 Cyanobacteria: Harnessing Nature's Versatile Allies in Pharmaceuticals, Food, and Agriculture 186 production and the associated factors controlling their structural stability, strongly limit their commercialization and applications in the various fields of biotechnology.
... They have been extensively studied, and various effective antibacterial molecules have been identified among them, including alkaloids, fatty acids, pigments, phenolic compounds, terpenoids, peptides, and more. [46,47] Pratt et al. [48] first isolated an antibacterial compound from the microalga Chlorella, known as chlorellin, characterized as a mixture of fatty acids with inhibitory activity against both Gram-negative and Gram-positive bacteria. Sedighi et al. [49] characterized a 62 KDa peptide from Chlorella vulgaris that exhibited antibacterial activity by inhibiting the cell wall synthesis of Escherichia coli strains. ...
The excessive use of conventional antibiotics has resulted in significant aquatic pollution and a concerning surge in drug-resistant bacteria. Efforts have been consolidated to explore and develop environmentally friendly antimicrobial alternatives to mitigate the imminent threat posed by multi-resistant pathogens. Antimicrobial peptides (AMPs) have gained prominence due to their low propensity to induce bacterial resistance, attributed to their multiple mechanisms of action and synergistic effects. Microalgae, particularly cyanobacteria, have emerged as promising alternatives with antibiotic potential to address these challenges. The aim of this review is to present some AMPs extracted from microalgae, emphasizing their activity against common pathogens and elucidating their mechanisms of action, as well as their potential application in the aquaculture industry. Likewise, the biosynthesis, advantages and disadvantages of the use of AMPs are described. Currently, biotechnology tolls are used to enhance the action of these peptides, such as genetically modified microalgae and recombinant proteins. Cyanobacteria are also mentioned as major producers of peptides, among them, the genus Lyngbya is described as the most important producer of bioactive peptides with potential therapeutic use. The majority of cyanobacterial AMPs are of the cyclic type, meaning that they have cysteine and disulfide bridges, thanks to this, their greater antimicrobial activity and selectivity. Likewise, we found that large hydrophobic aromatic amino acid residues increase specificity, and improve antibacterial efficacy. However, based on the results of this review, it is possible to highlight that while microalgae show potential as a source of AMPs, further research in this field is necessary to achieve safe and competitive production. Therefore, the data presented here can aid in the selection of microalgal species, peptide structures, and target bacteria, with the goal of establishing biotechnological platforms for aquaculture applications.
... Since the isolation of Chlorellin (a mixture of fatty acids with antibacterial action) from Chlorella spp. in 1944, research into the identification of novel antimicrobial compounds produced by microalgae has surged (Pratt et al., 1944). Several of these studies have determined the active molecules, which are often pigments, lipids, fatty acids, carbohydrates, flavonoids, and phenolic compounds belonging to the same class (Falaise et al., 2016). ...
In the current study, thirteen species of microalgae were isolated from the local
environment in the city of Baqubah and its surroundings. They were then
diagnosed based on approved sources. They Chlorella vulgaris, Cosmarium
subtumidum, Peridinium inconspicuum, Nitzschia amphibia, Nitzschia dissipata,
Nitzschia palea, Nitzschia sigmoidea, Fragilaria crotonensis, Oscillatoria
limnetica, Chroococcus spp., Nostoc calcicole, Phormidium lacuna, and,
Oscillatoria curviceps. In this study focused on Chlorella vulgaris from
Chlorophyta, and Oscillatoria limnetica from Cyanobacteria.
The active compounds from these microalgae were extracted using hexane in the
form of a crude extract. In addition, fatty acids were partially purified from
Chlorella vulgaris. The crude hexane extracts and Chlorella vulgaris fatty acids,
the bands present in the extracts were detected by Fourier Transform Infrared
Spectroscopy analysis determined (FTIR),15 clear bands from (3381.21- 671.23
cm-1
) for Chlorella vulgaris, 10 clear bands from (2960.73- 1261.45 cm-1
) for
Oscillatoria limnetica, and 11 clear bands from (3370 – 720 cm-1
) for fatty acids.
As for the active compounds, they were detected by Gas Chromatography-Mass
Spectrometry, and the compounds appeared in both Chlorella vulgaris and
Oscillatoria limnetica as follows: phenolic compounds, Nitrogen Compounds
Hydroxyl amines, Aldehydes, Fatty Acid Methyl Esters, diterpenoid and a long�chain primary fatty alcohol, fatty acid, long-chain fatty acids, Aromatic Solvents,
organic compounds known as phenylpropanes and Alkanes. Also, Dodecanoic acid,
9-Eicosene, (E)-, n-Hexadecanoic acid in Partial purification of fatty acid from
Chlorella vulgaris. The antimicrobial and antibiofilm properties of the hexane
extract of these two microalgae and Chlorella vulgaris fatty acids were
investigated in vitro against firstly Candida albicans and Candida glabrata, which
V
were clinically isolated from 100 renal impairment patients, and it was diagnosis
by some biochemical test. while secondly are Pseudomonas aeruginosa,
Acinetobacter baumannii, Proteus mirabilis, Klebsiella pneumoniae, streptococcus
faecalis, Streptococcus pyogenes, Staphylococcus epidermis and Staphylococcus
aureus, that have been obtained as ready isolates from burn and surgical patients
from Baqubah Teaching Hospital, and have been tested for resistance to antibiotics.
For bacteria which are (Vancomycin, Imipenem, Gentamicin, Levofloxacin,
Ciprofloxacin, Trimethoprim/sulfamethoxazole, Trimethoprim, Tetracycline,
Nitrofurantoin, Chloramphenicol, Clarithromycin, Amikacin, Piperacillin,
Penicillin G, Meropenem, Ampicillin, Ceftazidime, Tobramycin,
Piperacillin/tazobactam, Cefepime, Azithromycin). And (Amphotericin B,
Fluconazole) for fungi.
The results showed that crude hexane extract of Chlorella vulgaris and
Oscillatoria limnetica had a high effect as antimicrobial (Bacteria and Fungi).
According to statistical analysis, Chlorella vulgaris extracts excelled as antifungal
agents. While Oscillatoria limnetica extracts excelled as antibacterial. Their effect
is equal as an anti-biofilm Furthermore, Chlorella vulgaris fatty acids extract
showed superiority as an antibiofilm and as an antibacterial when it was applied at
two concentrations (10 and 100 mg/ml). For all Candida isolates the highest value
was 62mm for the Chlorella vulgaris extract. While the highest value for the
Oscillatoria limnetica extract was 40mm. The highest value recorded for
Oscillatoria limnetica extract was 90 mm for Pseudomonas aeruginosa, 23 mm
for, Acinetobacter baumannii, 25 mm for Proteus mirabilis, 30 mm for Klebsiella
pneumoniae and Staphylococcus epidermidis, and 50 mm for Staphylococcus
aureus and finally 32.5 mm for the Streptococcus spp. The highest value was
recorded for the Chlorella vulgaris extract, 50 mm for Pseudomonas aeruginosa,
VI
30 mm for Acinetobacter baumannii, Klebsiella pneumoniae and Staphylococcus
epidermidis, 25mm for both Staphylococcus aureus and Proteus mirabilis, and
finally 31 mm for the Streptococcus spp. Also, had a high effect as Antibiofilm
with three replicates. The average inhibition percentage of all Candida isolates
reached 79% for Chlorella vulgaris extract and 77.7% for Oscillatoria limnetica
extract. The average inhibition percentage reached 81.667% for both
concentrations (10 and 100 mg/ml) of fatty acids. The average inhibition
Percentage reached 83.4% for Chlorella extract and 83% for Oscillatoria extract
with Pseudomonas aeruginosa Isolates, 86.2% for Chlorella extract and 85.5% for
Oscillatoria extract with Acinetobacter baumannii. while 49.7% for Chlorella
extract and 46.7% for Oscillatoria extract with Proteus mirabilis, 43.7% for
Chlorella extract and 34.35% for Oscillatoria extract with Klebsiella pneumoniae,
while 58.7015% for Chlorella extract and 50.28 % for Oscillatoria extract with
Staphylococcus aureus and, 25.855% for Chlorella extract and 26.2203% for
Oscillatoria extract with Staphylococcus epidermidis. The average inhibition
percentage of fatty acids for all bacteria species reached 66.63% at 100 mg/ml, and
70.24% at 10 mg/ml. Finally, the cytotoxicity of fatty acids towards two cancer cell
lines and one normal cell line. The examination was carried out using MTT
technology. Six concentrations of the fatty acids extract were applied: 1000, 500,
250, 125, 62.5, and 31.2 µg/ml. Three replicates of each concentration were
applied. The highest inhibition rate observed in SR cells (lymphoma cell line SR)
was 47.7% and the IC50 was 142.5 µg/ml. While the highest inhibition rate in
MCF7 cells (Michigan Cancer Foundation –MCF7) (Breast Cancer) was 40.6%
recorded, the IC50 was 1032 µg/ml. Finally, the lowest inhibition rate of NHF
(Normal Human Dermal Fibroblasts NHF) was 0.00% in normal cells, and IC50
was 2gm/ml.
... HXY7, and Chlorella vulgaris FACHB 8 to WWVC may be due to the strong antimicrobial properties of algae. Pratt et al. [26] conducted a study that revealed the presence of an antibacterial substance in uncontaminated cultures of Chlorella sp. In addition to their antimicrobial properties, Chlorella was also reported as a facultative algal species that can not only use light energy for photosynthetic autotrophic growth but also use organic compounds as carbon sources for heterotrophic growth [27]. ...
... Chlorellin, a fatty acid mixture isolated from Chlorella sp. in 1944, was the first identified antimicrobial compound from microalgae that inhibited both gram-positive and gram-negative bacteria [43]. Fatty acids act on bacteria by impairing the electron transport chain and oxidative phosphorylation, thereby reducing nutrient uptake leading to bacterial cell lysis [22]. ...
... Among the more abundant metabolites across all strains, notable compounds include (9Z)-9-Octadecenamide, Traumatin, Umbelliferone, Xestoaminol, 4-Linoleamide, and palmitamide. Umbelliferone, also known as 7-hydroxycoumarin, belongs to the coumarin family and has been shown to possess antimicrobial properties, functioning particularly as an antibacterial [54] and antifungal agent [55], as well as exhibiting antioxidant properties [56]. However, it has not been tested as an inhibitor of growth or seed germination. ...
The excessive use of synthetic pesticides has caused environmental problems and human health risks and increased the development of resistance in several organisms. Allelochemicals, secondary metabolites produced as part of the defense mechanisms in plants and microorganisms, are an attractive alternative to replace synthetic pesticides to remediate these problems. Microalgae are natural producers of a wide range of allelochemicals. Thus, they provide new opportunities to identify secondary metabolites with pesticide activities and an alternative approach to discover new modes of action and circumvent resistance. We screened 10 green microalgae strains belonging to the Chlorophyta phylum for their potential to inhibit the growth of photosynthetic and nonphotosynthetic organisms. Bioassays were established to assess microalgae extracts’ effectiveness in controlling the growth of Chlorella sorokiniana, Arabidopsis thaliana, Amaranthus palmeri, and the model nematode Caenorhabditis elegans. All tested strains exhibited herbicidal, nematocidal, or algicidal activities. Importantly, methanol extracts of a Chlamydomonas strain effectively controlled the germination and growth of a glyphosate-resistant A. palmeri biotype. Likewise, some microalgae extracts effectively killed C. elegans L1 larvae. Comprehensive metabolic profiling using LC-MS of extracts with pesticide activities showed that the metabolite composition of Chlamydomonas, Chlorella, and Chloroidium extracts is diverse. Molecules such as fatty acids, isoquinoline alkaloids, aldehydes, and cinnamic acids were more abundant, suggesting their participation in the pesticide activities.
... This antibiotic, which corresponds to a mixture of fatty acids from the microalgae Chlorella sp., showed antimicrobial activity against grampositive and gram-negative bacteria. 120 Since then, several compounds obtained from photoautotrophic microorganisms with antibacterial activity have been characterized, such as fatty acids, polyphenols, biphenyls, polysaccharides, and nanoparticles, each showing different mechanisms of action. 107 Regarding strains from mangroves, Silva-Stenico et al. 117 also evaluated the antimicrobial activity using the intracellular extract of the cyanobacteria tested. ...
Photoautotrophic microorganisms, such as microalgae and cyanobacteria, are known to perform an essential role in ecological functions. Besides, they are considered cell factories, producing various bioproducts of commercial interest. In mangroves, these microorganisms are primarily responsible for the ecosystem's high productivity. Moreover, the unique natural characteristics of mangroves, coupled with the intense pressure from anthropic activities that these ecosystems typically experience, make mangrove photoautotrophic microbiota biotechnologically attractive. In this work, the ecological role and biotechnological potential of photoautotrophic mangrove microorganisms worldwide were evaluated, highlighting, their ecosystem services and bioproducts with environmental and commercial appeal, as well as their strategic and technological application through patent analysis. © 2023 Society of Industrial Chemistry and John Wiley & Sons Ltd.
... Furthermore, since the 1950s, microalgae have been examined as potential biotechnological sources of biologically active compounds (BACs), antimicrobial extracts, and extracellular products. The first antibacterial compound was isolated from a microalga by Pratt et al. (1944). They found gram-positive and gramnegative bacteria to be sensitive to Chlorellin. ...
Nitrogen stress can influence microalgae’s growth characteristics, and microalgae grown in nitrogen-deficient conditions may produce higher or lower levels of biotechnological products as a result of metabolic changes. In photoautotrophic and heterotrophic cultures, nitrogen limitation has been proven effective in promoting lipid accumulation. In spite of this, no study has demonstrated a significant correlation between lipid content and other biotechnological products such as bioactive compounds (BACs). This research examines a strategy for lipid accumulation as well as the potential production of BACs with antibacterial properties in parallel with that strategy. This concept involved the treatment of the microalga Auxenochlorella protothecoides with low and high concentrations of ammonium (NH4+). This particular experiment reached a maximum lipid content of 59.5% using a 0.8 mM NH4+ concentration, resulting in the yellowing of the chlorophyll levels. Agar diffusion assays were conducted to determine the antibacterial activity of different extracts derived from the biomass when stressed with different levels of nitrogen. Algal extracts prepared by a variety of solvents showed different levels of antibacterial activity against representative strains of both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. Among the extracts tested, 500 mg/L ethyl acetate extract had the greatest antibacterial activity against Escherichia coli. In order to identify the components responsible for the extract’s antibacterial activity, fatty acid methyl ester (FAME) analysis was performed. It has been suggested that the lipid fraction may be a valuable indicator of these activities since some lipid components are known to possess antimicrobial properties. In this regard, it was found that the amount of polyunsaturated fatty acid (PUFA) significantly decreased by 53.4% under the conditions with the highest antibacterial activity observed.
... were present as opposed to regions in which they weren't. [40]. Dunaliella cells reportedly contained antimicrobial compounds, according to Chang aureus was impervious to minolenic acid isolated from Chlorococcum sp. ...
Microalgae have a very diverse genetic makeup and can manifest as single cells, clusters, or filamentous. They are widely dispersed throughout the biosphere and can practically thrive in any kind of habitat. Microalgae are thus among the most hopeful participants in blue bioengineering because, in addition to their remarkable metabolic adaptability, they only need inexpensive inorganic P and N sources, store CO2 as a basic nutrient, and depend on sunshine for energy. They are also well known for their abundance of bioactive substances, which have the potential to be used in drug formulations. Some of these compounds are especially effective against microorganisms in aquaculture and food processing, while others have antibacterial, antiviral, antifungal, and antialgal characteristics. However, to prevent using subtherapeutic quantities of normal antibiotics or synthetic antimicrobial compounds, cell-free extracts of these bacteria have been studied as food and feed supplements. In addition, many chemical compounds produced from microalgae, with acetogenins, fatty acids, indoles, phenols, terpenes, and some halogenated compounds that are volatile, have demonstrated antibacterial action. a study on the lipid content of supercritical preparations of the microalga Chaetoceros muelleri has demonstrated antibacterial action. Several types of algae are also successful in fighting off various pathogens. Pithophora oedogonium, for instance, concentrates on Salmonella and Staphylococcus species. Furthermore, The phytoplankton Colpomenia peregrina sauvageau, Codium delicate, Cystoseira barbata,Nostoc spongiaeforme, and Rivularia bullata are lethal to a wide range of Gram-negative and Gram-positive microorganisms.
... The first studies on the antibiotic activity of microalgae were performed on Chlorella (Pratt, 1942;Pratt et al., 1944). Since then, the potential antimicrobial activities of extracts derived from different microalgae have been described (Falaise et al., 2016;Kellam & Walker, 1989;Ördög et al., 2004;Plaza et al., 2010;Rojas et al., 2020;Shannon & Abu-Ghannam, 2016). ...
Dunaliella tertiolecta RCC6 was cultivated indoors in glass bubble column photobioreactors operated under batch and semi‐continuous regimens and using two different conditions of light and temperature. Biomasses were harvested by centrifugation, frozen and then lyophilized. The soluble material was obtained by sequential extraction of the lyophilized biomass with solvents with a gradient of polarity (hexane, ethyl acetate and methanol) and its metabolic composition investigated through nuclear magnetic resonance (NMR) spectroscopy. The effect of light on chlorophyll biosynthesis was clearly shown through the relative intensities of the 1H NMR signals due to pheophytins. The highest signal intensity was observed for the biomasses obtained at lower light intensity, resulting in a lower light availability per cell. Under high temperature and light conditions, the 1H NMR spectra of the hexane extracts showed an incipient accumulation of triacylglycerols. In these conditions and under semi‐continuous regimen, an enhancement of β‐carotene and sterols production was found. The antibacterial and antibiofilm activities of the extracts were also tested. Antibacterial activity was not detected, regardless culture conditions. In contrast, the minimal biofilm inhibitory concentrations (MBICs) against Escherichia coli for the hexane extract obtained under semi‐continuous regimen using high temperature and irradiance conditions was promising.
... Therefore, microalgae can be an inventive basis for antimicrobial compounds production. The first antibacterial compound isolated from microalgae is chlorellin in 1940's (Pratt et al. 1944). Short chain fatty acids present in the liquid ethanolic extract of Haematococcus pluvialis showed antimicrobial activity against Escherichia coli and Staphylococcus aureus (Santoyo et al. 2009). ...
The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.
Graphical abstract
... Some studies have been conducted on the allelochemicals of Chlorella. Pratt et al. (1944) isolated chlorellin from cell-free culture solutions of Chlorella and demonstrated its antibacterial properties. Fergola et al. (2007) found that chlorellin produced by C. vulgaris inhibits P. subcapitata. ...
Harmful algal blooms caused by Heterocapsa bohaiensis have broken out in aquaculture areas near Liaodong Bay, China, since 2012, resulting in mass mortality of Eriocheir sinensis larvae and substantial economic loss. Chlorella pyrenoidosa is a local phytoplankton species that is found in aquaculture ponds. However, the reason why H. bohaiensis dominated and proliferated in the phytoplankton community remains unknown. Previous studies have revealed the toxicity and hemolytic activity of H. bohaiensis. It is suspected that the out-competition of H. bohaiensis to C. pyrenoidosa was associated with toxicity. Filtrate and bi-algal cultures were investigated to determine the interspecific competition between H. bohaiensis and C. pyrenoidosa in this study. Filtrate experiments revealed that H. bohaiensis showed no toxin allelopathy in C. pyrenoidosa. However, the C. pyrenoidosa filtrates had significant allelopathic effects on the growth of H. bohaiensis. The bi-algal culture experiments and the simulation showed that the dominant species were dependent on the initial cell density ratios of the species and nutrient ratios. Therefore, H. bohaiensis achieved competitive advantage through exploitation competition but not allelopathy. The results contribute to the reasons for the occurrence of H. bohaiensis blooms in a further study.
... Chlorella biomass could be utilized as a bio-fertilizer. Pratt et al. (1944) who demonstrated that chlorellin, a mixture of fatty acids with antibacterial activity accumulated in the culture of Chlorella. Ostensvik et al. (1998) and Skulberg (2000) who revealed that methanolic extract of natural blooms of microalgae possessed more pronounced growth inhibition against several strains of bacteria than the aqueous extract. ...
... Изследванията върху антимикробната активност на Chlorella стартират през 1940 г. с работата на Pratt (1940), в която авторът показва, че микроводораслото произвежда субстанция, инхибираща неговия собствен растеж. В изследвания, проведени през следващите години, се стига до създаване на екстракт с антимикробни свойства наречен "хлорелин" (Pratt and Fong, 1940;Pratt et al. 1944). ...
Микробните и вирусните инфекции водят както до проблеми с общественото здраве, така и до икономически значими загуби (напр. когато засягат земеделски култури и съответно хранителната промишленост). Затова борбата срещу тях е едно от големите предизвикателства пред научната общност. Според План за дейността на Национален референтен център „Инфекции, предавани с храни и води“ (НРЦ-ИПХВ) от 2021 г., „инфекциозните заболявания, предавани с храни и води, са световен здравен проблем и по честота са на второ място след респираторните инфекции“. В документа се отбелязва, че най-често заболяванията на стомашно-чревния тракт „се предават по орален път чрез консумация на контаминирани храни“.
Към този момент човечеството притежава ограничен брой лекарствени средства за системно приложение. Основен проблем е появата на щамове, които са резистентни към един или повече от използваните антибиотични лекарства и други медикаменти. Справянето с резистентни бактериални щамове води до необходимост от търсене на нови лекарствени продукти. Една от причините за възникването на резистентни бактерии е неконтролируемото използване на антибиотици не само за лечение на хора, но също така във ветеринарната практика и в земеделието. Така попадането и влагането на лекарства в хранителни продукти може да има последствие върху човешкото здраве. Затова въпреки, че проблемите с живота и здравето на хората винаги е от първостепенно значение, учените по цял свят обръщат не по-малко внимание и върху проблемите свързани с качеството на храните.
Намаляването или дори загубата на добив на селскостопанската продукция, често се дължи на различни причини. Една от тях е липсата на достатъчно ефективна защита на растенията от болести, причинявани от фитопатогенни бактерии, наречени „бактериози“. Пестицидите са едно от основните средства за борба с вредителите в земеделието, но основен недостатък на използването им е това, че влияят неблагоприятно върху околната среда и прекомерната им употреба може да крие риск за здравето на животни и хора. Така напр. сярата и сероваровият разтвор са най-често използваните за борба срещу струпясването при ябълката, но те са фитотоксични за растенията и въпреки, че не са канцерогенни, могат да предизвикат респираторни проблеми при хора. Някои учени твърдят, че в резултат на продължително въздействие на тези продукти са се увеличили заболявания като Паркинсон, диабет тип 2, някои видове рак, ендокринни нарушения, невротоксичност, астма и дори затлъстявания. Според EPA 2010 повече от 70 пестицида са класифицирани като потенциално канцерогенни. Околната среда също е засегната от използването на синтетични пестициди, които се натрупват в почвата и замърсяват подпочвените води.
В момента по света се наблюдават множество тревожни тенденции - значителното увеличаване на замърсяването с пестициди, от една страна, и появата на все по-резистентни бактериални щамове предизвикващи инфекции, от друга. Към това може да се прибави и опасността от кръстосаните патогени – човешки патогени, които се интегрират в растителен или животински микробиом. Бактериите, които контаминират храната, заразяват хората и причиняват хранителни болести като например диария. Заразените храни включват бактерии и бактериални спори, микроскопични гъби, вируси, дрожди и др.
Може да се твърди, че нарастващата резистентност на вредните бактерии увеличава и нуждата от увеличение на употребата на пестициди. Тази зависимост е много тревожна и е напълно възможно да се достигне до много неприятни последици за земеделието. Затова в последните години се увеличи значително интересът към проучванията на биологични ефекти на природни съединения срещу бактериални и/или гъбични инфекции.
... The liberation of these fatty acids and lipophilic substances is induced by cell lysis of microalgae already damaged by predators or pathogens. These sacrificial cells protect the culture from further damage since they act as signals or precursors that activate downstream systemic defense responses; this mechanism has also been shown in Phaeodactylum tricornutum cultures [38]. ...
Microalgae and cyanobacteria are photosynthetic microorganisms’ sources of renewable biomass that can be used for bioplastic production. These microorganisms have high growth rates, and contrary to other feedstocks, such as land crops, they do not require arable land. In addition, they can be used as feedstock for bioplastic production while not competing with food sources (e.g., corn, wheat, and soy protein). In this study, we review the macromolecules from microalgae and cyanobacteria that can serve for the production of bioplastics, including starch and glycogen, polyhydroxyalkanoates (PHAs), cellulose, polylactic acid (PLA), and triacylglycerols (TAGs). In addition, we focus on the cultivation of microalgae and cyanobacteria for wastewater treatment. This approach would allow reducing nutrient supply for biomass production while treating wastewater. Thus, the combination of wastewater treatment and the production of biomass that can serve as feedstock for bioplastic production is discussed. The comprehensive information provided in this communication would expand the scope of interdisciplinary and translational research.
... Extracts from Pavlova sp., obtained using a combination of methanol/chloroform solvents, acted against V. parahaemolyticus and P. aeruginosa, with a GIZ of 10 cm [27]. garis [69]. The substance that inhibits the growth of bacteria was referred to as chlorellin. ...
Algae are proving to be an exciting new source of therapeutics, and various species, including green algae, red algae, and diatoms, are being studied for their potential to improve human health. It is an incredibly diverse organism containing various compounds that can be used for medicinal purposes. It can be used to treat a spectrum of diseases, including diabetes, cancer, heart disease, and even neurological disorders. In many cases, algae-based treatments are more effective than traditional pharmaceuticals due to their ability to target specific areas of the body. For example, certain types of algae contain compounds that can help reduce inflammation in the body and even improve cognitive function. Additionally, algae-based treatments are often more affordable than traditional medicines and can be administered in various ways. This makes them an attractive option for those seeking alternative treatments for their health concerns. In addition, they can be modified quickly to produce a wide array of compounds. Scientists are investigating various approaches to deliver the chemicals manufactured by these organisms and are steadily recognizing new objectives for drug development. This chapter could help develop more effective remedies for various diseases and ailments, render algae a promising opportunity in disease therapeutics, explore different methods of administering the compounds produced by these organisms, and identify new targets for drug discovery.
A number of advancements have been made in algal technology in different fields, such as medical, cosmetic, and pharmaceutical. Green algae (Chlorophyta) are a group of photosynthetic organisms which live in both aquatic and terrestrial environments. They are a potential source of bioactive compounds for the treatment and prevention of a wide range of infectious diseases caused by microorganisms. These compounds also possess anti-inflammatory, antioxidant, anticoagulant, antitumor, and immunomodulatory properties. A wide variety of bioactive compounds are produced, including polysaccharides, which exhibit antimicrobial properties capable of interfering with the cell walls, membranes, and nucleic acids of microorganisms. Membrane fluidity, permeability, or integrity can be affected by polyphenols and fatty acids which scavenge free radicals, chelate metal ions, or disrupt enzymes and membranes. Proteins and peptides form pores within the membranes which bind to specific receptors or inhibit enzymes. Adaptation to adverse environmental conditions, such as temperature extremes, photooxidation, salinity, or osmotic stress, results in the formation of bioactive compounds by altering the physiological and biochemical pathways of algae for the maintenance of cellular homeostasis. With changing consumer preferences and an increase in the number of resistant microorganisms, it is critical to seek novel antimicrobial compounds from green algae. The search for novel bioactive compounds with antimicrobial properties from green algae may serve as an alternative in the light of increased drug resistance in microorganisms. However, in vitro and in vivo evaluations of the safety, efficacy, and mechanism of action of the antimicrobial compounds from green algae require more research. Providing an overview of previous endeavours in this emerging field, this review provides perspectives and a summary of the bioactive compounds responsible for the antimicrobial properties of green algal extracts.
Pesticide use in crops is a severe problem in some countries. Each country has its legislation for use, but they differ in the degree of tolerance for these broadly toxic products. Several synthetic pesticides can cause air, soil, and water pollution, contaminating the human food chain and other living beings. In addition, some of them can accumulate in the environment for an indeterminate amount of time. The agriculture sector must guarantee healthy food with sustainable production using environmentally friendly methods. In this context, biological biopesticides from microbes and plants are a growing green solution for this segment. Several pests attack crops worldwide, including weeds, insects, nematodes, and microorganisms such as fungi, bacteria, and viruses, causing diseases and economic losses. The use of bioproducts from microorganisms, such as microbial biopesticides (MBPs) or microorganisms alone, is a practice and is growing due to the intense research in the world. Mainly, bacteria, fungi, and baculoviruses have been used as sources of biomolecules and secondary metabolites for biopesticide use. Different methods, such as direct soil application, spraying techniques with microorganisms, endotherapy, and seed treatment, are used. Adjuvants like surfactants, protective agents, and carriers improve the system in different formulations. In addition, microorganisms are a tool for the bioremediation of pesticides in the environment. This review summarizes these topics, focusing on the biopesticides of microbial origin.
The diverse marine environment compared to terrestrial is a great treasure in discovering many new bioactive substances. By living in a competitive and hostile environment, marine organisms tend to survive and live within complex communities and also have close associations with others. Due to the ecological pressure such as predation, habitat competition, variation in tide, etc. as a response, the marine organisms produce composite secondary metabolites which are unique and abundant in marine sources that can be used as anti-microbial agents such as antiviral, antibacterial, antifungal and antiprotozoal agents. Since marine organisms produce a variety of compounds with antimicrobial activities they can be used in the production of pharmacological products to treat infections, diseases, etc. This chapter discusses the potential sources that are available in marine organisms that can act as therapeutic agents with antimicrobial activities. It also briefly explains different bioactive substances produced by different marine organisms that can be used in pharmaceutical industries.
As novel biomedical materials, microalgae have garnered significant interest because of their ability to generate photosynthetic oxygen, their antioxidant activity, and their favorable biocompatibility. Many studies have concentrated on the hypoxia-alleviating effects of microalgae within tumor microenvironments. However, recent findings indicate that microalgae can significantly increase the regeneration of various tissues and organs. To augment microalgae's therapeutic efficacy and mitigate the limitations imposed by immune clearance, it is essential to process microalgae through various processing strategies. This review examines common microalgal species in biomedical applications, such as Chlorella, Chlamydomonas reinhardtii, diatoms, and Spirulina. This review outlines diverse processing methods, including microalgae extracts, microalgae‒nanodrug composite delivery systems, surface modifications, and living microalgae‒loaded hydrogels. It also discusses the latest developments in tissue repair using processed microalgae for skin, gastrointestinal, bone, cardiovascular, lung, nerve, and oral tissues. Furthermore, future directions are presented, and research gaps for processed microalgae are identified. Collectively, these insights may inform the innovation of processed microalgae for various uses and offer guidance for ongoing research in tissue repair.
Microalgae are the unicellular, autotrophic organisms present in marine or fresh water environment. They may be present as single cell or in the form of colonies. Microalgae are the source of various substances that are beneficial for health like proteins, lipids, lutine, precursors of vitamins, carotenoids and vitamin A, B1, B3, B6, B12, E. Furthermore, the use of microalgae for medicinal purposes can be traced back to ancient Chinese medicines due to their antibiotic, antimycobacterial, antiviral, anti-inflammatory, analgesic, antipyretic, antiproliferative, and cytotoxic activities. Recent advances in science and technology have revealed the drawback of using synthetic products for health and environment. This revelation has compelled people to use natural products. With the increasing trend of organic products in every sector of life and their benefits over synthetic products, utilization of microalgae has also gain popularity in various sectors viz., food, pharmaceuticals, cosmetics, cosmeceuticals, biofuel, biofertilizers, bioplastics, waste water treatment, aquaculture etc. Products from microalgae help preserving the environment and reduction of environmental pollution. Microalgae are also useful in bioremediation of heavy metals like; mercury, lead, chromium, cadmium and arsenic from water. One of the examples of utilization of microalgae as food is Spirulina, which is now commercially available in the form of powder and tablets. It is known as super food because of its high macro and micronutrient content. It is also used and feed for domestic animals and fish. Other commercially grown microalgae include Chlorella, Skeletonema, Tetraselmis, Isochrysis, Pavlova, Phaeodactylum, Chaetoceros, Nannochloropsis, Oscillatoria etc. For the commercial utilization, microalgae can be cultivated in open ponds (circular ponds or raceways), closed ponds (tubular or flat-plate photobioreactors) or in natural water bodies then harvested and processed for respective use. Despite of their utilization in various products, microalgae cultivation faces many challenges like high production and maintenance cost, contamination by other microorganisms. To overcome these challenges further research and development of more cost effective and efficient methods are required.
A complex evaluation of antimicrobial activities of microalgae, including those relevant to wastewater treatment (WWT), in light of the integrated biorefinery concept, is performed. An example of this concept is linking a commercial microalgal system to plants, factories, or farms that emit polluted wastewater (WW). The microalgae would not only metabolize the pollutants—such as nitrogen (N) and phosphorus (P)—from the WW, thus fueling their biomass, but they would exert an antibacterial effect against the pathogenic bacteria there. The biomass then could be harvested and used for biofertilizers, biofuels, and bioplastics and might possibly be utilized as animal feed, antimicrobial and other pharmaceutical agents. A large amount of the research on the antimicrobial activity and WWT potential focuses on the families Chlorellaceae and Scenedesmaceae, which are also some of the most commercially used strains of microalgae. For that reason, they are the species chosen for the current review. Furthermore, the increasing antimicrobial resistance necessitates the search for antibiotic alternatives, and the antibacterial and antifungal activity of Chlorellaceae and Scenedesmaceae is very promising. Microalgae are rich in antibacterial compounds like polyunsaturated fatty acids (PUFAs), polysaccharides, carotenoids, proteins, etc., and for that reason, their extracts possess antimicrobial effects. The in vitro antimicrobial activity of Chlorellaceae and Scenedesmaceae families has varied in a broad range from low to strong activity or no effect. Several strains have fulfilled the criteria for outstanding and high activity, especially C. vulgaris and other Chlorellaceae spp., with an effect equal to or better than the control antibiotics. There were several strains with minimum inhibitory concentrations (MIC) below 80 µg/mL and even 10 and 1.5 µg/mL; some species also had inhibition zones (IZ) over 30 mm, even as high as 48 mm. In vivo results are also promising but scarce, and all this warrants further in vivo and in situ studies—from animal models to clinical and environmental trials. Altogether, important data in the light of the circle economy, the urgent necessity to decrease CO2 emissions to fight climate change, and to curb the harmful influence of future pandemics are presented. This review paves the way for further utilizing the total potential of a microalgal system.
A study of the antibacterial properties of a non-polar extract of microalgae Chlorella sorokiniana on gram-positive bacteria is presented along with a determination of the minimum inhibitory concentrations of the mixture and the individual metabolites that make up the extract. A regular effect of illumination on the intensity of the antibiotic effect of non-polar microalgae extract on gram-positive bacteria is demonstrated. A mixture of substances extracted from disintegrated cells of the microalgae biomass Chlorella sorokiniana has an inhibitory effect on bacterial growth at a photosynthetically active radiation level of 100±6 μmol photons/(m ² ×s). The minimum effective amount of the extract is 330±11.09 µg. When analysing the chemical structure of the components of the non-polar fraction extracted from the cells of microalgae Chlorella sorokiniana, the composition of the non-polar extract was shown to include triacylglycerides, fatty acids, o-dialkyl monoglycerides and ethers of sterols or waxes, or trialkyl esters of glycerol. When studying the antibiotic properties of individual fractions of substances, triacylglycerides and fatty acids were found to have an antibiotic effect on gram-positive bacteria. In this case, the minimum effective amount of triacylglycerides is 400±13.37 μg, while that of fatty acids is 600±20.05 μg. The combined effect of a mixture of non-polar extract substances gives the most pronounced antibiotic effect on gram-positive bacteria at a photosynthetically active radiation level of 100±6 μmol of photons/(m ² ×s). Thus, an increase in antibacterial action was demonstrated when using a mixture of substances of the non-polar extract of microalgae Chlorella sorokiniana at a photosynthetically active radiation level of 100±6 μmol of photons/(m ² ×s).
Seaweeds are screened extensively for their activity against human bacterial pathogens. In the present study, the petroleum ether, butanol, chloroform, acetone and methanol extracts of seaweed species, viz., Caulerpa racemosa, Padina gymnospora, Sargassum wightii and Ulva fasciata were investigated for their antibacterial properties by well diffusion method against human pathogenic bacteria (Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Streptococcus mutans). Preliminary qualitative analysis on the chemical constituents of the twenty seaweed crude extracts revealed the predominant presence of phenols and tannins. Antibacterial activity of the seaweed extracts were represented by zone of inhibition. The order of maximum antibacterial activity (represented by very strong zone of inhibition) was exhibited by Padina gymnospora petroleum ether extract against Staphylococcus aureus (23.6mm) and Pseudomonas aeruginosa (21.6mm), and its butanol extract against Pseudomonas aeruginosa (20.5mm). From the overall results of the present study, it was observed that Padina gymnospora extracts exhibited maximum antibacterial activity, attributed to the presence of the active chemical constituents, especially phenols and tannins. Further in depth studies are recommended, as Padina gymnospora extracts could serve as an additional implement to natural antibacterial agents.
The growing interest in plant-based medicines, considered safer and more reliable ("green medicine"), is steering a paradigm shift in combatting infections, especially in aquaculture. Medicinal plants, acknowledged for their antibacterial properties, present a compelling alternative to synthetic antimicrobials, potentially alleviating their detrimental effects. Aquatic plants, especially seaweeds, are emerging as robust reservoirs of bioactive compounds, sparking interest in allelopathic research. Seaweeds, teeming with diverse bioactive compounds, hold immense promise for the development of functional ingredients and therapeutic drugs. Their sophisticated chemical defense mechanisms, honed to combat microbial threats, augur well in the battle against human and fish bacterial pathogens, as well as various diseases. This study meticulously focuses on appraising the antibacterial potential of unique extracts derived from the submerged aquatic plant Ceratophyllum demersum (Coontail) against clinical isolates of fish bacterial pathogens. The research endeavors to offer invaluable insights into leveraging aquatic plants as a natural remedy to combat bacterial diseases in fish, emphasizing the promotion of sustainable practices within the aquaculture industry.
Microalgae are a source of scientific curiosity and inspiration for their utilization as ‘inoculants’ in agriculture and the commercial production of high-value products. Their diversity and abundance in the soil environment highlight the fact that these integral members of the soil microbial community modify the physical and chemical conditions of soils and interact with other microorganisms and even with higher plants with varying degrees of association. However, to date, the agronomic benefits of the nitrogen fixation trait of cyanobacteria have not been fully realized. Thus, the ecological functions of these organisms in the biological soil crusts should be thoroughly evaluated and widely applied given that climate change events can increase desertification. Currently, the crop yield increments and pest control due to these biostimulants and the reclamation of saline and sodic soils by these bioameliorants are considered economically marginal. Similarly, the carbon capture and storage by eukaryotic microalgae and cyanobacteria in soils are poorly understood. Limitations in their commercial production for agricultural use include inadequate technological innovations and the enormous expectation for yield increments, together with the contemporary monetization of their environmental benefits. Thus, this critical review presents the desirable reappraisal of their agronomic benefits and the invigoration of research and culture collections to utilize these organisms or their metabolites, considering the evolutionary consequences and environmental advantages and finally their commercial production for widespread application in agriculture.
An essential aspect of product quality of aquatic foods is the rapid and accurate identification of bacterial species. From this perspective omics technologies prove to be very useful in the assessment of the quality and safety of seafood products. Such technologies can identify and detect low levels of contamination by pathogenic and spoilage bacteria and can be used to study the effects caused by processing and storage of seafood products. The integration of food processing with the monitoring of the microbial characteristics using conventional microbiological assays, coupled to molecular techniques may establish the baseline for the development of quicker and more sensitive and reliable methods for seafood safety screening. The use of combined omics technologies, including metagenomics, proteomics and metabolomics, coupled to conventional quality indices such as colour, texture and flavour offer a new tool for novel processing optimization to ensure seafood quality. The aim of this brief review is to outline how omics technologies can generate novel tools for integration into seafood processing and quality control. Considering that the main aspect of the review is the improvement of safety and quality of the final product, from production to consumption, emphasis is given to microbial identification and metabolite detection, the evaluation of the allergenic capacity of fish and seafood and optimization of postharvest processing. Deployment of omics for identification of potential microalgal products of relevance to seafood quality and safety is also considered.
Background
Inflammatory bowel disease (IBD) was regarded as a problem of the industrialised nations. However, with the popularity and convenience connected to ultra-processed food, fast food and restaurant dining, and due to the lack of appropriate strategies to avoid foodborne microbes, the disease started to emerge in other parts of the world also. Bacterial imbalance, intestinal permeability, and the associated dysbiosis-caused polarization of immune components to their pro-inflammatory phenotypes are implicated in the development of IBD. Now IBD is reported in children too, indicating the urgent need to take actions by finding diet components that can stall the proliferation of undesirable bacteria in our intestine.
Scope and approach
We present algae as a novel source for prebiotics to combat IBD. We first give an overview of IBD and the associated microbes. Next, we describe the unhealthy diet-induced microbes that are also connected to the disease and the foodborne microbes that are implicated in IBD. Then, we reveal the advantages of ‘biotic’ approaches such as using probiotic bacteria like bifidobacteria and lactobacilli and prebiotics from microalgae and macroalgae as well as a synbiotic strategy to combat IBD. In the end, we give suggestions for assessment of selected probiotics and prebiotics to counter pathogens or stimulate the growth of good bacteria in the intestine.
Key findings and conclusions
Dietary intervention, as a ‘biotic’ route, employing probiotics and bioactive compounds with prebiotic potential, and a combination of the two may provide a future path to control IBD because such strategies could thwart the proliferation of pathogens and development of intestinal dysbiosis.
In this study, the focus will be primarily on antimicrobials extracted from Microalgae Chlorella from stacked water from three different places. The results provide dates for possible applications in the pharmaceutical industry for developing antiseptic and antimicrobial products to guarantee the health of the people. The study initially outlines the isolation of microalgae and secondly was the extraction of chlorellin as an antimicrobial metabolite. To replicate the environmental conditions which are useful for growth colonies of Chlorella it was maintained at room temperature, oscillating between 10 °C to 18 °C in Bold Basal medium enriched with NH4Cl. After that, chlorellin was extracted from aqueous supernatant and sediment with ethanol, isopropyl alcohol, and water. The results of this study show that the chlorellin extracted from Chlorella present an essential antimicrobial capacity against bacteria isolated from the hand. The antimicrobial capacity was equal with ampicillin and oxacillin to inhibit Staphylococcus spp.
This study aimed to assess the effects of dietary addition with Chlorella sorokiniana on fish growth, gut histology, antioxidant capacity, immune response, and disease resistance in rainbow trout. Three diets with similar proximate composition and different Chlorella meal levels were formulated. The control diet, 5% Chlorella diet, and 10% Chlorella diet contained 0%, 5% Chlorella meal, and 10% Chlorella meal, respectively. Each diet was assigned to triplicate tanks containing 30 fish (165.3 ± 0.6 g) in each tank. Fish were fed experimental diets for ninety days. The results showed that the addition of 5% Chlorella in the diet significantly increased feed intake by 19.3% and weight gain rate by 17.3% (P < 0.05) without affecting feed efficiency and gut histology. Diets containing Chlorella meal significantly decreased malonaldehyde contents in the plasma after the lipopolysaccharide (LPS) challenge (P < 0.05). Dietary supplementation with Chlorella meal significantly increased lysozyme (LZM) activity levels (in the head kidney) and immunoglobulin M (IgM) (in the head kidney) and complement component 3 (C3) (in the spleen) contents before the LPS challenge, and simultaneously increased LZM activity levels (in the plasma) and C3 contents (in the plasma and head kidney) after the LPS challenge (P < 0.05). Furthermore, dietary administration of Chlorella meal significantly increased the survival rate of fish infected with Aeromonas salmonicida (P < 0.05). In conclusion, C. sorokiniana can be used to improve fish growth, antioxidant capacity, and immunity.
- R Pratt
- American Journal
- R Pratt
- American Journal