Natural Astaxanthin Is a Green Antioxidant Able to Counteract Lipid Peroxidation and Ferroptotic Cell Death.

Astaxanthin is a red orange xanthophyll carotenoid produced mainly by microalgae but which can also be chemically synthesized. As demonstrated by several studies, this lipophilic molecule is endowed with potent antioxidant properties and is able to modulate biological functions. Unlike synthetic astaxanthin, natural astaxanthin (NAst) is considered safe for human nutrition, and its production is considered eco-friendly. The antioxidant activity of astaxanthin depends on its bioavailability, which, in turn, is related to its hydrophobicity. In this study, we analyzed the water-solubility of NAst and assessed its protective effect against oxidative stress by means of different approaches using a neuroblastoma cell model. Moreover, due to its highly lipophilic nature, astaxanthin is particularly protective against lipid peroxidation; therefore, the role of NAst in counteracting ferroptosis was investigated. This recently discovered process of programmed cell death is indeed characterized by iron-dependent lipid peroxidation and seems to be linked to the onset and development of oxidative-stress-related diseases. The promising results of this study, together with the "green sources" from which astaxanthin could derive, suggest a potential role for NAst in the prevention and co-treatment of chronic degenerative diseases by means of a sustainable approach.

Inter- and Intraspecific Variability of Nitrogenated Compounds in Gorgonian Corals via Application of a Fast One-Step Analytical Protocol.

Gorgonian corals play a structural role in temperate and tropical biogenic reefs, forming animal forests and creating biodiversity hot spots. In the Mediterranean Sea, slow-growing and long-lived gorgonian species are threatened by human disturbances and global environmental changes and concern about their conservation is rising. Alkaloid metabolites have proven to be essential in protecting these species from environmental stressors. Traditional profiling methodologies to detect these metabolites require a large quantity of living tissue. Here, the chemodiversity of gorgonian alkaloids was investigated by applying a fast and effective protocol combining extraction and derivatization using small-scale tissue samples and GC/MS analysis. The method was effective in identifying and quantifying alkaloids and guanine-based compounds. Eight N-heterocyclic compounds were found in six Mediterranean gorgonians differing for types and quantity. The metabolomic profile was conservative in species of the Eunicella genus, with three species sharing the same pattern. Conversely, Paramuricea clavata displayed a noticeable spatial pattern of variation among colonies collected in different locations. The analytical approach presented here proved to be effective, allowing rare, endangered, and small-sized species to be screened rapidly for detection of new compounds in order to explore their biological and ecological functions.

Renewable Alkenes from the Hydrothermal Treatment of Polyhydroxyalkanoates-Containing Sludge.

Polyhydroxyalkanoates (PHA) are a key constituent of excess sludge produced by Aerobic Sewage Sludge Treatment plants. The accumulation of significant amount of PHA inside aerobic microbial cells occurs when a surplus of an easily degradable carbon source (e.g., volatile fatty acids, VFA) is found in combination with other nutrients limitation. Herein, hydrothermal treatment (HT) of PHA-containing sludge at 300 and 375 °C was demonstrated to be effective in converting most (>70% w/w) of the bacterial PHA stored inside microbial cells into alkene/CO2 gas mixtures. Simultaneously, most of non-PHA biomass was converted into water-soluble compounds (50% carbon yield) that were acidogenic fermented to produce volatile fatty acids, ideal substrate to feed aerobic bacteria and produce more PHA. According to results here presented, HT of excess sludge with moderate (13%) PHA content can produce about 50 kg of alkenes per tonne of suspended solids treated, with a significant reduction of sludge mass (80% reduction of wet sludge volume) and consequent disposal cost.

Chemical and ecotoxicological properties of three bio-oils from pyrolysis of biomasses.

In view of the potential use of pyrolysis-based technologies, it is crucial to understand the environmental hazards of pyrolysis-derived products, in particular bio-oils. Here, three bio-oils were produced from fast pyrolysis of pine wood and intermediate pyrolysis of corn stalk and poultry litter. They were fully characterized by chemical analysis and tested for their biodegradability and their ecotoxicity on the crustacean Daphnia magna and the green alga Raphidocelis subcapitata. These tests were chosen as required by the European REACH regulation. These three bio-oils were biodegradable, with 40-60% of biodegradation after 28 days, and had EC50 values above 100mgL(-1) for the crustacean and above 10mgL(-1) for the alga, showing low toxicity to the aquatic life. The toxic unit approach was applied to verify whether the observed toxicity could be predicted from the data available for the substances detected in the bio-oils. The predicted values largely underestimated the experimental values.

Customizing properties of ß-chitin in squid pen (gladius) by chemical treatments.

The squid pen (gladius) from the Loligo vulgaris was used for preparation of ß-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The ß-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the ß-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the ß-chitin is modified, due to the intercalation of water molecules between ß-chitin sheets. Potential applications of these ß-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications.

Carbon dot/polylactic acid nanofibrous membranes for solar-mediated oil absorption/separation: Performance, environmental sustainability, ecotoxicity and reusability.

Carbon dots (CDs) are promising photothermal nanoparticles that can be utilized in environmental treatments. They exhibit favorable physicochemical properties, including low toxicity, physical and chemical stability, photo-dependant reversible behaviour, and environmentally friendly synthesis using benign building blocks. Here, we synthesized innovative CDs/polylactic acid (PLA) electrospun composite membranes for evaluating the removal of hydrophobic compounds like long-chain hydrocarbons or oils in biphasic mixtures with water. The ultimate goal was to develop innovative and sustainable solar-heated oil absorbents. Specifically, we fabricated PLA membranes with varying CD contents, characterized their morphology, thermal, and mechanical properties, and assessed the environmental impact of membrane production according to ISO 14040 and 14044 standards in a preliminary "cradle-to-gate" life cycle assessment study. Solar radiation experiments demonstrated that the CDs/PLA composites exhibited greater uptake of hydrophobic compounds compared to pure PLA membranes, ascribable to the CDs-induced photothermal effect. The adsorption and regeneration capacity of the new CDs/PLA membrane was demonstrated through multiple uptake/release cycles. Ecotoxicity analyses confirmed the safety profile of the new adsorbent system towards freshwater microalgae, further emphasizing its potential as an environmentally friendly solution for the removal of hydrophobic compounds in water treatment processes.

Extraction of astaxanthin from Haematococcus pluvialis with hydrophobic deep eutectic solvents based on oleic acid.

Three novel hydrophobic deep eutectic solvents (DESs) based on oleic acid and terpenes (thymol, dl-menthol, and geraniol) were prepared, characterized, and used to extract astaxanthin from the microalga Haematococcus pluvialis without any pre-treatment of the cells. The three DES were composed of Generally Recognized As Safe (GRAS) and edible ingredients. All the tested DESs gave astaxanthin recovery values of about 60 and 30% in 6 h if applied on freeze-dried biomass or directly on algae culture, respectively. The carotenoid profile was qualitatively identical to what was obtained by using traditional organic solvents, regardless of the DES used; the monoesters of astaxanthin with C18-fatty acids were the main compounds found in all the carotenoid extracts. The thymol:oleic acid DES (TAO) could preserve astaxanthin content after prolonged oxidative stress (40% of the astaxanthin initially extracted was still present after 13.5 h of light exposure), thanks to the superior antioxidant properties of thymol. The capacity of improving astaxanthin stability combined with the intrinsic safety and edibility of the DES components makes the formulation astaxanthin-TAO appealing for the food ingredients/additives industry.

Allelopathic interactions between phytobenthos and meiofaunal community in an Adriatic benthic ecosystem: Understanding the role of aldehydes and macroalgal structural complexity.

Macroalgae produce several allelopathic substances, including polyunsaturated aldehydes (PUAs), which may inhibit photosynthesis and growth rates of other algal species, and grazing. Additionally, macroalgal structural complexity is an important factor in determining abundance patterns and size structure of epiphytic organisms. In this study the PUAs production of two Mediterranean macroalgae, Dictyopteris polypodioides, (DP, Phaeophyceae, Dictyotales) and Cystoseira compressa (CC, Phaeophyceae, Fucales), was characterized to clarify the relationships between the meiobenthic and microphytobenthic communities. Results showed a higher PUAs production and a diverse qualitative profile for DP, which reported long-chain compounds (i.e. C14-C16) as main aldehydes, than CC, with the short-chain C6:2 as the main compound, as well as variability among sampling times. A clear separation of the meiofauna and microphytobenthos assemblages was found for the macroalgae, but with different temporal trends. Dissimilarities were due to five microalgal orders, namely Naviculales, Lyrellales, Gonyaulacales (i.e. Ostreopsis), Bacillariales, and Licmophorales, and to the meiofaunal groups nematodes, copepods, and copepod nauplii, which were more abundant on DP than on CC. Results indicate that macroalgal complexity is a major determinant of the meiofaunal community structure (accounting for 26% of the variation), rather than PUAs production itself (17%). PUAs effects seem species-specific, thus affecting some grazers instead of the entire community. Conversely, microphytobenthos affected the meiofauna assemblages, particularly harpacticoids, confirming the role of these organisms as the primary food source of all marine food chain producers. Since PUAs are produced also by several epiphytic diatoms, the understanding of their effects on the community structure and on the relationships among taxa in the field is complicated and requires further in-depth investigations in simplified systems (i.e. microcosms).

Effects of imidazolium ionic liquids on growth, photosynthetic efficiency, and cellular components of the diatoms Skeletonema marinoi and Phaeodactylum tricornutum.

This article describes the toxic effects of imidazolium ionic liquids bearing alkyl (BMIM), monoethoxy (MOEMIM), and diethoxy (M(OE)(2)MIM) side chains toward two marine diatoms, Skeletonema marinoi and Phaeodactylum tricornutum. MOEMIM and M(OE)(2)MIM cations showed a lower inhibition of growth and photosynthetic efficiency with respect to their alkyl counterpart, with both algal species. However, a large difference in sensitivity was found between S. marinoi and P. tricornutum, the first being much more sensitive to the action of ionic liquids than the second one. The effects of salinity on BMIM Cl toxicity toward S. marinoi revealed that a decrease from salinity 35 to salinity 15 does not influence the biological effects toward the alga. Finally, Fourier transform infrared (FT-IR) microscopy of algal cells after ionic liquids exposure allowed us to detect an alteration of the organic cellular components related to silica uptake and organization. On the basis of these results, the different behavior of the two diatom species can be tentatively ascribed to different silica uptake and organization in outer cell walls.

Recovery of Polyhydroxyalkanoates From Single and Mixed Microbial Cultures: A Review.

An overview of the main polyhydroxyalkanoates (PHA) recovery methods is here reported, by considering the kind of PHA-producing bacteria (single bacterial strains or mixed microbial cultures) and the chemico-physical characteristics of the extracted polymer (molecular weight and polydispersity index). Several recovery approaches are presented and categorized in two main strategies: PHA recovery with solvents (halogenated solvents, alkanes, alcohols, esters, carbonates and ketones) and PHA recovery by cellular lysis (with oxidants, acid and alkaline compounds, surfactants and enzymes). Comparative evaluations based on the recovery, purity and molecular weight of the recovered polymers as well as on the potential sustainability of the different approaches are here presented.

Survey of the allelopathic potential of Mediterranean macroalgae: production of long-chain polyunsaturated aldehydes (PUAs).

Chemical interactions between macroalgae and other organisms play an important role in determining species compositions and dominance patterns, and can explain the widespread success of some species in establishing their predominant populations in a specific coastal area. Allelopathy could act as a self-regulatory strategy of the algal community, being not only a succession regulator but also an active mechanism maintaining the species diversity especially in a delimited environment, such as the benthic ecosystem. Polyunsaturated aldehydes (PUAs) are among the most studied allelopathic compounds and are commonly released into the aquatic environment by different phytoplankton species in response to environmental stressors (e.g. wounding, grazing, or competition for nutrients). Diatom-released PUAs were observed to affect phytoplankton community dynamics and structure, and showed inhibitory effects on the reproduction and development of marine invertebrates. As for macroalgae, there are only a few reports that attest to the production of PUAs, and mostly refer to Ulva spp. In this study, the production of PUAs by several Mediterranean macroalgae was investigated at different sampling times, aiming at providing the first evidence of potential allelochemical activity. Results highlighted the potential production by macroalgae of a variety of aldehydes, among which some have never reported so far. Some species (i.e. D. polypodioides and U. cf. rigida) were found to produce higher PUAs amounts than others, and even a wider variety of structures (e.g. length of the carbon chain); these species might exert strong effects on epiphytic species or other organisms of the benthic community, especially considering the differential sensitivities of the various taxa. A high dPUA concentration (order of µM) potentially due to the release of PUAs by algal species was found, and might affect the population dynamics of the epiphytic organisms (e.g. microalgae, meiofauna), of grazers, as well as of the microbial community.

The skeleton of Balanophyllia coral species suggests adaptive traits linked to the onset of mixotrophy.

The diversity in the skeletal features of coral species is an outcome of their evolution, distribution and habitat. Here, we explored, from macro- to nano-scale, the skeletal structural and compositional characteristics of three coral species belonging to the genus Balanophyllia having different trophic strategies. The goal is to address whether the onset of mixotrophy influenced the skeletal features of B. elegans, B. regia, and B. europaea. The macroscale data suggest that the presence of symbiotic algae in B. europaea can lead to a surplus of energy input that increases its growth rate and skeletal bulk density, leading to larger and denser corals compared to the azooxanthellate ones, B. regia and B. elegans. The symbiosis would also explain the higher intra-skeletal organic matrix (OM) content, which is constituted by macromolecules promoting the calcification, in B. europaea compared to the azooxanthellate species. The characterization of the soluble OM also revealed differences between B. europaea and the azooxanthellate species, which may be linked to diverse macromolecular machineries responsible for skeletal biosynthesis and final morphology. Differently, the crystallographic features were homogenous among species, suggesting that the basic building blocks of skeletons remained a conserved trait in these related species, regardless of the trophic strategy. These results show changes in skeletal phenotype that could be triggered by the onset of mixotrophy, as a consequence of the symbiotic association, displaying remarkable plasticity of coral skeletons which repeatedly allowed this coral group to adapt to a range of changing environments throughout its geological history.

Production of polyhydroxybutyrate by the cyanobacterium cf. Anabaena sp.

Polyhydroxybutyrate (PHB) production by the cyanobacterium cf. Anabaena sp. was here studied by varying the medium composition and the carbon source used to induce mixotrophic growth conditions. The highest PHB productivity (0.06 gPHB gbiomass-1 d-1) was observed when cultivating cf. Anabaena sp. in phosphorus-free medium and in the presence of sodium acetate (5.0 g L-1 concentration), after an incubation period of 7 days. A content of 40% of PHB on biomass, a dry weight of 0.1 g L-1, and a photosynthetic efficiency equal to the control were obtained. The cyanobacterium was then grown on a larger scale (10 L) to evaluate the characteristics of the produced PHB in relation to the main composition of the biomass (the content of proteins, polysaccharides, and lipids): after an incubation period of 7 days, a content of 6% of lipids (52% of which as unsaturated fatty acids with 18 carbon atoms), 12% of polysaccharides, 28% of proteins, and 46% of PHB was reached. The extracted PHB had a molecular weight of 3 MDa and a PDI of 1.7. These promising results demonstrated that cf. Anabaena sp. can be included among the Cyanobacteria species able to produce polyhydroxyalkanoates (PHAs) either in photoautotrophic or mixotrophic conditions, especially when it is grown under phosphorus-free conditions.

Grape Pomace for Topical Application: Green NaDES Sustainable Extraction, Skin Permeation Studies, Antioxidant and Anti-Inflammatory Activities Characterization in 3D Human Keratinocytes.

Food waste is a global problem due to its environmental and economic impact, so there is great demand for the exploitation of new functional applications. The winemaking process leads to an incomplete extraction of high-value compounds, leaving the pomace still rich in polyphenols. This study was aimed at optimising and validating sustainable routes toward the extraction and further valorisation of these polyphenols, particularly for cosmeceutical applications. New formulations based on red grape pomace polyphenols and natural deep eutectic solvents (NaDESs) were here investigated, namely betaine combined with citric acid (BET-CA), urea (BET-U) and ethylene glycol (BET-EG), in which DESs were used both as extracting and carrying agents for polyphenols. The flavonoid profile determined by HPLC-MS/MS analysis showed similar malvidin content (51-56 µg mL-1) in the DES combinations, while BET-CA gave the best permeation performance in Franz cells, so it was further investigated in 3D human keratinocytes (HaCat spheroids) injured with the pro-oxidant agent menadione. BET-CA treatment showed good intracellular antioxidant activity (IC50 0.15 ± 0.02 µg mL-1 in malvidin content) and significantly decreased (p < 0.001) the release of the pro-inflammatory cytokine IL-8, improving cell viability. Thus, BET-CA formulation is worthy of investigation for potential use as a cosmetic ingredient to reduce oxidative stress and inflammation, which are causes of skin aging.

Introduction of oxygenated side chain into imidazolium ionic liquids: evaluation of the effects at different biological organization levels.

The biological effects of a class of oxygenated imidazolium ionic liquids were studied in comparison with alkyl imidazolium salts (BMIM BF4 and BMIM N(CN)2).The cellular and subcellular effects were evaluated on rat pheochromocytoma PC12 cell lines, through MTT test, lactate dehydrogenase release and acetylcholinesterase inhibition; the eco-toxicological responses were assessed through the acute toxicity tests towards Daphnia magna and Vibrio fischeri. The introduction of ethoxy moieties in the lateral chain of imidazolium cations reduced the biological effects in all the tests. The acute toxicity towards D. magna was not affected by the number of ethoxy units, but the crustacean seemed to be sensitive to the type of anion; on the contrary, a further addition of ethoxy moieties increased the toxicity towards V. fischeri, M(OE)4MIM N(CN)2 being the most toxic oxygenated ionic liquid. In the cytotoxicity assays the salts with oxygenated cations resulted ineffective compared to BMIMs, independently from the anion and the number of ethoxy units in the lateral chain. In order to estimate the influence on membrane fluidity, an analysis of fluorescence anisotropy was done and it indicated that BMIM BF4, the most toxic ionic liquid among the tested ones, led to a destabilization of the model membranes at any molarity.

Organogel Coupled with Microstructured Electrospun Polymeric Nonwovens for the Effective Cleaning of Sensitive Surfaces.

Hydrogels and organogels are widely used as cleaning materials, especially when a controlled solvent release is necessary to prevent substrate damage. This situation is often encountered in the personal care and electronic components fields and represents a challenge in restoration, where the removal of a thin layer of aged varnish from a painting may compromise the integrity of the painting itself. There is an urgent need for new and effective cleaning materials capable of controlling and limiting the use of solvents, achieving at the same time high cleaning efficacy. In this paper, new sandwich-like composites that fully address these requirements are developed by using an organogel (poly(3-hydroxybutyrate) + γ-valerolactone) in the core and two external layers of electrospun nonwovens made of continuous submicrometric fibers produced by electrospinning (either poly(vinyl alcohol) or polyamide 6,6). The new composite materials exhibit an extremely efficient cleaning action that results in the complete elimination of the varnish layer with a minimal amount of solvent adsorbed by the painting layer after the treatment. This demonstrates that the combined materials exert a superficial action that is of utmost importance to safeguard the painting. Moreover, we found that the electrospun nonwoven layers act as mechanically reinforcement components, greatly improving the bending resistance of organogels and their handling. The characterization of these innovative cleaning materials allowed us to propose a mechanism to explain their action: electrospun fibers play the leading role by slowing down the diffusion of the solvent and by conferring to the entire composite a microstructured rough superficial morphology, enabling to achieve outstanding cleaning performance.

Use of waste carbon dioxide and pre-treated liquid digestate from biogas process for Phaeodactylum tricornutum cultivation in photobioreactors and open ponds.

Phaeodactylum tricornutum is considered a promising source of polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA). In this study, P. tricornutum cultivation using waste products from anaerobic digestion (i.e. liquid digestate and CO2) was tested and scaled-up in closed and open prototype systems. The chemical composition of algal biomass was evaluated to optimize the lipid content. Algal productivity and composition, especially in terms of PUFAs, were not modified by the use of waste CO2. Digestate led to a lower protein (24%) content than medium (36-37%), without affecting lipid amount (about 37%). Algal and EPA productivity were nearly two-fold higher by using photobioreactors (0.075 g biomass L-1 day-1 and 1.62 mg EPA g-1 day-1) than open ponds, which are more influenced by environmental conditions. This study highlights that economic and environmental benefits could be achieved by using waste CO2 and liquid digestate from anaerobic digestion for microalgae cultivation.

Acute toxicity of oxygenated and nonoxygenated imidazolium-based ionic liquids to Daphnia magna and Vibrio fischeri.

Room-temperature ionic liquids (RTILs) recently have generated great interest as a result of their potential commercial applications. In particular, because of their negligible vapor pressure and low inflammability, they have been suggested as green alternatives to traditional organic solvents. The toxicity and potential environmental risk of this heterogeneous class of chemicals, however, are poorly understood. An alkyl-substituted RTIL, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]), is one of the most widely used cations of RTILs, and information regarding its toxicity is relatively extensive. On the other hand, oxygenated chain-substituted ionic liquids, 1-methoxyethyl-3-methylimidazolium salts (moemims), are a new class of RTILs that have been poorly studied. Here, we compared the acute toxicity of [bmim][BF(4)] and moemims to the crustacean Daphnia magna (end point, 48-h immobilization) and the bacterium Vibrio fischeri (end point, 15-min inhibition of bioluminescence). The concentrations of [bmim][BF(4)] resulting in 50% of the maximum adverse effect (EC50s) for D. magna and V. fischeri were 5.18 and 300 mg/L, respectively, and were consistent with previously published values. The EC50s of the two moemims for D. magna are very similar, ranging from 209 to 222 mg/L in different experimental trials, and are higher by two orders of magnitude than the EC50 of [bmim][BF(4)]. The EC50s of 1-methoxyethyl-3-methylimidazolium tetrafluoroborate ([moemim][BF(4)]) and 1-methoxyethyl-3-methylimidazolium dicyanamide ([moemim][dca]) for V. fischeri are 3,196 and 2,406 mg/L, respectively. Results indicate that introduction of an oxygenated side chain in the imidazolium cation can greatly reduce the toxicity of RTILs and that these RTILs are less toxic than commonly used chlorinated solvents, such as tricloromethane, but are more toxic than nonchlorinated solvent, such as methanol and acetone.

PUFAs and PUAs production in three benthic diatoms from the northern Adriatic Sea.

The production of polyunsaturated aldehydes (PUAs) has been reported by many planktonic diatoms, where they have been implicated in deleterious effects on copepod reproduction and growth of closeby microbes or suggested as infochemicals in shaping plankton interactions. This study investigates the production of PUAs by diatoms commonly occurring in the microphytobenthic communities in temperate regions: Tabularia affinis, Proschkinia complanatoides and Navicula sp. Results highlight the production of PUAs by the three benthic diatoms during stationary and decline phases, with intracellular concentrations from 1.8 to 154.4 fmol cell-1, which are within the range observed for planktonic species. The existence of a large family of PUAs, including some with four unsaturations, such as decatetraenal, undecatetraenal and tridecatetraenal, was observed. Since particulate and dissolved PUAs were positively correlated, together with cell lysis, equivalent concentrations may be released during late growth stages, which may affect benthic invertebrates grazing on them and other microalgae.

Ecological relevance of skeletal fatty acid concentration and composition in Mediterranean scleractinian corals.

The intra-skeletal fatty acid concentration and composition of four Mediterranean coral species, namely Cladocora caespitosa, Balanophyllia europaea, Astroides calycularis and Leptopsammia pruvoti, were examined in young and old individuals living in three different locations of the Mediterranean Sea. These species are characterized by diverse levels of organization (solitary or colonial) and trophic strategies (symbiotic or non-symbiotic). Fatty acids have manifold fundamental roles comprehensive of membrane structure fluidity, cell signaling and energy storage. For all species, except for B. europaea, the intra-skeletal fatty acid concentration was significantly higher in young individuals than in old ones. Moreover, fatty acid concentration was higher in colonial corals than in solitary ones and in the symbiotic corals compared to non-symbiotic ones. Analysis by gas chromatography-mass spectrometry (GC-MS) revealed that palmitic acid (16:0) was the most abundant fatty acid, followed by stearic (18:0) in order of concentration. Oleic acid (18:1) was detected as the third main component only in skeletons from symbiotic corals. These results suggest that, in the limits of the studied species, intra-skeletal fatty acid composition and concentration may be used for specific cases as a proxy of level of organization and trophic strategy, and eventually coral age.