In this work, a membrane-based separation was investigate for Scenedesmus almeriensis solutions d... more In this work, a membrane-based separation was investigate for Scenedesmus almeriensis solutions dewatering. A commercial polyvinylidene fluoride (PVDF) membrane, having a pore size of 3 ?m was used in order to allow the water passage through it (permeate), retaining, at the same time, algae biomass (retentate). The possibility to reuse the permeate for a second Scenedesmus almeriensis growth step, was also studied. The registered data evidenced the feasibility of the membrane-based dewatering as an alternative competitive technology, even though the recovery of water should need further investigations to be optimized.
Background Pressurised anaerobic digestion allows the production of biogas with a high content of... more Background Pressurised anaerobic digestion allows the production of biogas with a high content of methane and, at the same time, avoid the energy costs for the biogas upgrading and injection into the distribution grid. The technology carries potential, but the research faces practical constraints by a.o. the capital investment needed in high-pressure reactors and sensors and associated sampling limitations. In this work, the kinetic model of an autogenerative high-pressure anaerobic digestion of acetate, as the representative compound of the aceticlastic methanogenesis route, in batch configuration, is proposed to predict the dynamic performance of pressurised digesters and support future experimental work. The modelling of autogenerative high-pressure anaerobic digestion in batch configuration, which is not extensively studied and simulated in the present literature, was developed, calibrated, and validated by using experimental results available from the literature. Results Under ...
Nutraceuticals have gained growing attention during the last year, becoming one of the most relev... more Nutraceuticals have gained growing attention during the last year, becoming one of the most relevant areas of investigation. Among the existing natural sources of high value bioactive compounds, microalgae have assumed paramount importance. Indeed, they are a natural source of carotenoids, essential omega-3 fatty acids, proteins, carbohydrates, pigments, vitamins and minerals. Among these components, beta-carotene, a potent antioxidant pigment, is particularly attractive to the nutraceutical and cosmetic sector, being an ingredient in many supplements, functional, cosmetic and pharmaceutical products. Moreover, beta-carotene is one of the forms (precursor) of Vitamin A, which may be used in the manufacture of food supplements according to Directive 2002/46/EC. Even though some cyanobacteria produce beta-carotene (80% of total carotenoids) as the major components followed by zeaxanthin, the commercial biological source of beta-carotene is Dunaliella salina. This microalga lives in ve...
Lutein is a powerful carotenoid that is used as a feed additive for the colouring properties and ... more Lutein is a powerful carotenoid that is used as a feed additive for the colouring properties and as supplement in nutraceutical products. Its principal healthy properties are antioxidant, anti-inflammatory and protective against age-related macular degeneration. Lutein is indeed a macular pigment in human eyes between zeaxanthin and their function is very important for the eyes health. Lutein is found in some vegetables as spinach, parsley, and kale with a content of around 1-10 mg/100 g. The commercial and recognized source of lutein is the plant marigold (Tagetes erecta L.). Lutein is extracted from marigold petals as oleoresin and the lutein content can be around 0.03% (based on dry biomass weight). Since the costs for harvesting are expensive, land and water use are requested for marigold cultivation and due to the seasonality of the growth, an alternative source of lutein has been searched among microalgae. Scenedesmus almeriensis is considered a promising source for lutein pro...
Microalgae as Alternative Source of Nutraceutical Polyunsaturated Fatty Acids Antonio Molino, Ang... more Microalgae as Alternative Source of Nutraceutical Polyunsaturated Fatty Acids Antonio Molino, Angela Iovine, Gianpaolo Leone, Giuseppe Di Sanzo, Salvatore Palazzo, Maria Martino, Paola Sangiorgio, Tiziana Marino, Dino Musmarra ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Territorial and Production System Sustainability Department, CR Portici Piazzale Enrico Fermi, 1 80055 Portici (NA), Italy Department of Engineering, University of Campania “Luigi Vanvitelli”, Via Roma, 29 81031 Aversa, Italy. [email protected] ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department of Sustainability-CR Casaccia, Via Anguillarese 301, Rome (RM), 00123, Italy ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department of Sustainability-CR ENEA Trisaia, SS Jonica 106, km 419+500, 75026 Rotondella (MT), Italy [email protected]
Immobilization of living cells is a useful technique that allows to enhance the biotechnological ... more Immobilization of living cells is a useful technique that allows to enhance the biotechnological properties of many organisms. Currently, cell-immobilization is obtained via carrier adsorption, self-aggregation and entrapment. We are currently investigating the possibility to immobilize microalgae cells using magnetic nanoparticles on a magnetic surface. The principle is based on the introduction, inside the cell-body of microalgae, superparamagnetic nanoparticles through electroporation. Once microalgae have absorbed enough magnetic nanoparticles they will be responding to an external magnetic field. By using a flat magnetic surface, it will be possible to trap them in a specific position by means of magnetic force. Importantly, immobilized cells will be covered with a thin layer of water and during cell division only one of the daughter cells will keep the magnetic nanoparticles since they will face permanently the magnetic surface. The first step towards this goal is the introduc...
Microalgae have been long recognized as potential food and feed solution, since they are able to ... more Microalgae have been long recognized as potential food and feed solution, since they are able to meet the population growth on demand for a more sustainable food and feed, especially with respect to protein production. In addition, bioactive components, such as eicosapentaenoic acid (EPA), with well-known antioxidant and anti-inflammatory properties, can be extracted and incorporated in food supplements. Microalgae cultivation and processing becomes even more sustainable if simultaneously coupled to green technologies for the environmental protection. One of the most promising techniques is the supercritical fluid extraction which allows to extract bioactive compounds without loss of their activity and free from extraction solvents. In this work, a pilot scale supercritical CO2 (ScCO2) extraction plant was exploited for performing the extraction of active components from microalgae biomass potentially usable in the food and the feed sectors. Nannochloropsis gaditana microalga was se...
This work presents a risk analysis of a plant that uses supercritical fluid extraction technology... more This work presents a risk analysis of a plant that uses supercritical fluid extraction technology with carbon dioxide as a solvent to obtain bioproducts from microalgae.Given the high pressure at which it operates, the extraction plant called "Luwar" could be affected by dangerous events, such as the gas release in concentrations that are harmful to human health. In order to limit the damage, the risk analysis is of primary importance.The gas release could occur following the breakage of a pipe, which was the scenario being considered. It was analyzed using the commercial software "Phast & Safeti", an alternative tool to the methods traditionally used in the literature in hazard events of this type, such as the Threshold Limit Value-Time Weighted Average (TLV-TWA) and the Threshold Limit Value-Short Term Exposure Limit (TLV-STEL), that are defined on the basis of the characteristics of the substance dispersed in the air.Since the pressure of the extraction vessel...
Anaerobic digestion is a technology used to biologically convert organic substrates into biogas i... more Anaerobic digestion is a technology used to biologically convert organic substrates into biogas in the absence of oxygen. The resulting biogas is a renewable energy source mainly consisting of a mixture of methane (60÷70% v/v) and carbon dioxide (30÷40% v/v), with traces of some minor compounds, such as H2S and NH3. Anaerobic digestion takes place through a sequence of four biological phases - hydrolysis, acidogenesis, acetogenesis, and methanogenesis - performed by the action of particular species of bacteria. Operating parameters such as temperature, pH, pressure and organic substrates govern the process and affect the starting biomass transformation and the content of methane into the biogas. The biogas from anaerobic digestion can be upgraded to biomethane by removing CO2 and the minor compounds. The techniques commonly used for this purpose, like pressure swing adsorption and membrane separation, are energy-intensive as they require the compression of biogas. In this paper, an ...
The aim of this study was to develop an effective integrated cultivation system for Haematococcus... more The aim of this study was to develop an effective integrated cultivation system for Haematococcus pluvialis as a source of bioactive compounds such as astaxanthin, lutein, proteins, and fatty acids (FAs). The Chlorophyta H. pluvialis was cultivated in a vertical bubble column photobioreactor (VBC-PBR) under batch mode, allowing switching from green to red phase for astaxanthin induction. The combined effect of light intensity and nutrients on bioactive compound formation was investigated. Results showed that growth under lower nutrients availability and light intensity led to a higher concentration of biomass. Growth under high light intensity with an appropriate concentration of nitrate, sulfate, phosphate and magnesium led to ~85% and ~58% higher production of total carotenoids and fatty acids, respectively. Under high stress conditions, ~90% nitrate and phosphate consumption were observed.
Several bacteria pathogens are responsible for plant diseases causing significant economic losses... more Several bacteria pathogens are responsible for plant diseases causing significant economic losses. The antibacterial activity of Dunaliella salina microalgae extracts were investigated in vitro and in vivo. First, biomass composition was chemically characterized and subjected to extraction using polar/non-polar solvents. The highest extraction yield was obtained using chloroform:methanol (1:1 v/v) equal to 170 mg g−1 followed by ethanol (88 mg g−1) and hexane (61 mg g−1). In vitro examination of hexane extracts of Dunaliella salina demonstrated antibacterial activity against all tested bacteria. The hexane extract showed the highest amount of β-carotene with respect to the others, so it was selected for subsequent analyses. In vivo studies were also carried out using hexane extracts of D. salina against Pseudomonas syringae pv. tomato and Pectobacterium carotovorum subsp. carotovorum on young tomato plants and fruits of tomato and zucchini, respectively. The treated young tomato pla...
Haematococcus pluvialis microalgae is a promising source of astaxanthin, an excellent antioxidant... more Haematococcus pluvialis microalgae is a promising source of astaxanthin, an excellent antioxidant carotenoid. H. pluvialis, as well as other species, could find more extensive applications as healthy food for a variegated carotenoids composition in addition to astaxanthin. Official method has not currently been used for this purpose. The objective of this work was to propose a method to characterize carotenoids in H. pluvialis after the comparison between spectrophotometric and liquid chromatography analysis. In addition, in order to improve the use of astaxanthin in the food industry, thermal stability was investigated. In this context, the effect of temperature at 40–80 °C, over a 16 h storage period was tested on astaxanthin produced by H. pluvialis. A further test was carried out at room temperature (20 °C) for seven days. A decrease in the astaxanthin concentration was observed at all tested temperatures with a decrease >50% of all-trans isomer at 80 °C after 16 h and an inc...
The present study aimed to develop an integrated treatment of agro-industrial waste for biofuel (... more The present study aimed to develop an integrated treatment of agro-industrial waste for biofuel (biogas and syngas) production and for phosphorus recovery. In the first step, an anaerobic digestion (AD) process was carried out on two different mixtures of raw agro-industrial residues. Specifically, a mixture of asparagus and tomato wastes (mixture-1) and a mixture of potatoes and kiwifruit residues (mixture-2) were investigated. The results proved that the properties of mixtures notably affect the evolution of the digestion process. Indeed, despite the lower organic load, the maximum biogas yield, of about 0.44 L/gCODremoved, was obtained for mixture-1. For mixture-2, the digestion process was hindered by the accumulation of acidity due to the lack of alkalinity in respect to the amount of volatile fatty acids. In the second step, the digestates from AD were utilized for syngas production using supercritical water gasification (SCWG) at 450 °C and 250 bar. Both the digestates were r...
In this article, microalgae Nannochloropsis sp. was used for fatty acid (FA) extraction, using a ... more In this article, microalgae Nannochloropsis sp. was used for fatty acid (FA) extraction, using a supercritical fluid-carbon dioxide (SF-CO2) extraction method. This study investigated the influence of different pre-treatment conditions by varying the grinding speed (200–600 rpm), pre-treatment time (2.5–10 min), and mixing ratio of diatomaceous earth (DE) and Nannochloropsis sp. biomass (0.5–2.0 DE/biomass) on FAs extraction. In addition, the effect of different operating conditions, such as pressure (100–550 bar), temperature (50–75 °C), and CO2 flow rate (7.24 and 14.48 g/min) on eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) recovery, was analyzed. Experimental data evidenced that, keeping constant the extraction conditions, the pre-treatment step enhanced the FAs extraction yield up to 3.4 fold, thereby the maximum extracted amount of FAs (61.19 mg/g) was attained with the pre-treatment with a ratio of DE/biomass of 1 at 600 rpm for 5 min. Moreover, by increasing bot...
This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology fo... more This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology for the extraction of high interest compounds for applications in the manufacturing of pharmaceuticals, nutraceuticals, and cosmetics from microalgae. The purpose of this study is to recover fatty acids (FAs) and, more precisely, eicosapentaenoic acid (EPA) from Nannochloropsis gaditana biomass by CO2-SF extraction. In the paper, the effect of mechanical pre-treatment was evaluated with the aim of increasing FAs recovery. Extraction was performed at a pressure range of 250–550 bars and a CO2 flow rate of 7.24 and 14.48 g/min, while temperature was fixed at 50 or 65 °C. The effect of these parameters on the extraction yield was assessed at each extraction cycle, 20 min each, for a total extraction time of 100 min. Furthermore, the effect of biomass loading on EPA recovery was evaluated. The highest EPA extraction yield, i.e., 11.50 mg/g, corresponding to 27.4% EPA recovery, was obtained at ...
Microalgae Dunaliella salina contains useful molecules such as β-carotene and fatty acids (FAs), ... more Microalgae Dunaliella salina contains useful molecules such as β-carotene and fatty acids (FAs), which are considered high value-added compounds. To extract these molecules, supercritical carbon dioxide was used at different operative conditions. The effects of mechanical pre-treatment (grinding speed at 0–600 rpm; pre-treatment time of 2.5–7.5 min) and operating parameters for extraction, such as biomass loading (2.45 and 7.53 g), pressure (100–550 bars), temperature (50–75 °C) and CO2 flow rate (7.24 and 14.48 g/min) by varying the extraction times (30–110 min) were evaluated. Results showed that the maximum cumulative recovery (25.48%) of β-carotene was achieved at 400 bars and 65 °C with a CO2 flow rate of 14.48 g/min, while the highest purity for stage (55.40%) was attained at 550 bars and 65 °C with a CO2 flow rate of 14.48 g/min. The maximum recovery of FAs, equal to 8.47 mg/g, was achieved at 550 bars and 75 °C with a CO2 flow rate of 14.48 g/min. Moreover, the lowest biomas...
Photocatalysis combined with membrane technology could offer an enormous potential for power gene... more Photocatalysis combined with membrane technology could offer an enormous potential for power generation in a renewable and sustainable way. Herein, we describe the one-step hydrogen and oxygen evolution through a photocatalytic membrane reactor. Experimental tests were carried out by means of a two-compartment cell in which a modified Nafion membrane separated the oxygen and hydrogen evolution semi-cells, while iron ions permeating through the membrane acted as a redox mediator. Nanosized Au/TiO2 and Au/CeO2 were employed as suspended photocatalysts for hydrogen and oxygen generation, respectively. The influence of initial Fe3+ ion concentration, ranging from 5 to 20 mM, was investigated, and the best results in terms of hydrogen and oxygen evolution were registered by working with 5 mM Fe3+. The positive effect of gold on the overall water splitting was confirmed by comparing the photocatalytic results obtained with the modified/unmodified titania and ceria. Au-loading played a key...
The production of biofuels from renewable sources is a major challenge in research. Methanol, eth... more The production of biofuels from renewable sources is a major challenge in research. Methanol, ethanol, dimethyl ether (DME), synthetic natural gas (SNG), and hydrogen can be produced from syngas which is the result of the gasification of biomasses. Syngas composition varies according to the gasification technology used (such as fixed bed reactors, fluidized bed reactors, entrained flow reactors), the feedstock characteristics, and the operating parameters. This paper presents a review of the predominant biomass gasification technologies and biofuels obtained from syngas by biomass gasification.
Thermal analysis of olive tree pruning and the by-products obtained by its gasification and pyrol... more Thermal analysis of olive tree pruning and the by-products obtained by its gasification and pyrolysis: The effect of some heavy metals on their devolatilization behavior
Astaxanthin and lutein, antioxidants used in nutraceutics and cosmetics, can be extracted from se... more Astaxanthin and lutein, antioxidants used in nutraceutics and cosmetics, can be extracted from several microalgal species. In this work, investigations on astaxanthin and lutein extraction from Haematococcus pluvialis (H. pluvialis) in the red phase were carried out by means of the supercritical fluid extraction (SFE) technique, in which CO2 supercritical fluid was used as the extracting solvent with ethanol as the co-solvent. The experimental activity was performed using a bench-scale reactor in semi-batch configuration with varying extraction times (20, 40, 60, and 80 min), temperatures (50, 65, and 80 °C) and pressures (100, 400, and 550 bar). Moreover, the performance of CO2 SFE with ethanol was compared to that without ethanol. The results show that the highest astaxanthin and lutein recoveries were found at 65 °C and 550 bar, with ~18.5 mg/g dry weight (~92%) astaxanthin and ~7.15 mg/g dry weight (~93%) lutein. The highest astaxanthin purity and the highest lutein purity were ...
In this work, a membrane-based separation was investigate for Scenedesmus almeriensis solutions d... more In this work, a membrane-based separation was investigate for Scenedesmus almeriensis solutions dewatering. A commercial polyvinylidene fluoride (PVDF) membrane, having a pore size of 3 ?m was used in order to allow the water passage through it (permeate), retaining, at the same time, algae biomass (retentate). The possibility to reuse the permeate for a second Scenedesmus almeriensis growth step, was also studied. The registered data evidenced the feasibility of the membrane-based dewatering as an alternative competitive technology, even though the recovery of water should need further investigations to be optimized.
Background Pressurised anaerobic digestion allows the production of biogas with a high content of... more Background Pressurised anaerobic digestion allows the production of biogas with a high content of methane and, at the same time, avoid the energy costs for the biogas upgrading and injection into the distribution grid. The technology carries potential, but the research faces practical constraints by a.o. the capital investment needed in high-pressure reactors and sensors and associated sampling limitations. In this work, the kinetic model of an autogenerative high-pressure anaerobic digestion of acetate, as the representative compound of the aceticlastic methanogenesis route, in batch configuration, is proposed to predict the dynamic performance of pressurised digesters and support future experimental work. The modelling of autogenerative high-pressure anaerobic digestion in batch configuration, which is not extensively studied and simulated in the present literature, was developed, calibrated, and validated by using experimental results available from the literature. Results Under ...
Nutraceuticals have gained growing attention during the last year, becoming one of the most relev... more Nutraceuticals have gained growing attention during the last year, becoming one of the most relevant areas of investigation. Among the existing natural sources of high value bioactive compounds, microalgae have assumed paramount importance. Indeed, they are a natural source of carotenoids, essential omega-3 fatty acids, proteins, carbohydrates, pigments, vitamins and minerals. Among these components, beta-carotene, a potent antioxidant pigment, is particularly attractive to the nutraceutical and cosmetic sector, being an ingredient in many supplements, functional, cosmetic and pharmaceutical products. Moreover, beta-carotene is one of the forms (precursor) of Vitamin A, which may be used in the manufacture of food supplements according to Directive 2002/46/EC. Even though some cyanobacteria produce beta-carotene (80% of total carotenoids) as the major components followed by zeaxanthin, the commercial biological source of beta-carotene is Dunaliella salina. This microalga lives in ve...
Lutein is a powerful carotenoid that is used as a feed additive for the colouring properties and ... more Lutein is a powerful carotenoid that is used as a feed additive for the colouring properties and as supplement in nutraceutical products. Its principal healthy properties are antioxidant, anti-inflammatory and protective against age-related macular degeneration. Lutein is indeed a macular pigment in human eyes between zeaxanthin and their function is very important for the eyes health. Lutein is found in some vegetables as spinach, parsley, and kale with a content of around 1-10 mg/100 g. The commercial and recognized source of lutein is the plant marigold (Tagetes erecta L.). Lutein is extracted from marigold petals as oleoresin and the lutein content can be around 0.03% (based on dry biomass weight). Since the costs for harvesting are expensive, land and water use are requested for marigold cultivation and due to the seasonality of the growth, an alternative source of lutein has been searched among microalgae. Scenedesmus almeriensis is considered a promising source for lutein pro...
Microalgae as Alternative Source of Nutraceutical Polyunsaturated Fatty Acids Antonio Molino, Ang... more Microalgae as Alternative Source of Nutraceutical Polyunsaturated Fatty Acids Antonio Molino, Angela Iovine, Gianpaolo Leone, Giuseppe Di Sanzo, Salvatore Palazzo, Maria Martino, Paola Sangiorgio, Tiziana Marino, Dino Musmarra ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Territorial and Production System Sustainability Department, CR Portici Piazzale Enrico Fermi, 1 80055 Portici (NA), Italy Department of Engineering, University of Campania “Luigi Vanvitelli”, Via Roma, 29 81031 Aversa, Italy. [email protected] ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department of Sustainability-CR Casaccia, Via Anguillarese 301, Rome (RM), 00123, Italy ENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Department of Sustainability-CR ENEA Trisaia, SS Jonica 106, km 419+500, 75026 Rotondella (MT), Italy [email protected]
Immobilization of living cells is a useful technique that allows to enhance the biotechnological ... more Immobilization of living cells is a useful technique that allows to enhance the biotechnological properties of many organisms. Currently, cell-immobilization is obtained via carrier adsorption, self-aggregation and entrapment. We are currently investigating the possibility to immobilize microalgae cells using magnetic nanoparticles on a magnetic surface. The principle is based on the introduction, inside the cell-body of microalgae, superparamagnetic nanoparticles through electroporation. Once microalgae have absorbed enough magnetic nanoparticles they will be responding to an external magnetic field. By using a flat magnetic surface, it will be possible to trap them in a specific position by means of magnetic force. Importantly, immobilized cells will be covered with a thin layer of water and during cell division only one of the daughter cells will keep the magnetic nanoparticles since they will face permanently the magnetic surface. The first step towards this goal is the introduc...
Microalgae have been long recognized as potential food and feed solution, since they are able to ... more Microalgae have been long recognized as potential food and feed solution, since they are able to meet the population growth on demand for a more sustainable food and feed, especially with respect to protein production. In addition, bioactive components, such as eicosapentaenoic acid (EPA), with well-known antioxidant and anti-inflammatory properties, can be extracted and incorporated in food supplements. Microalgae cultivation and processing becomes even more sustainable if simultaneously coupled to green technologies for the environmental protection. One of the most promising techniques is the supercritical fluid extraction which allows to extract bioactive compounds without loss of their activity and free from extraction solvents. In this work, a pilot scale supercritical CO2 (ScCO2) extraction plant was exploited for performing the extraction of active components from microalgae biomass potentially usable in the food and the feed sectors. Nannochloropsis gaditana microalga was se...
This work presents a risk analysis of a plant that uses supercritical fluid extraction technology... more This work presents a risk analysis of a plant that uses supercritical fluid extraction technology with carbon dioxide as a solvent to obtain bioproducts from microalgae.Given the high pressure at which it operates, the extraction plant called "Luwar" could be affected by dangerous events, such as the gas release in concentrations that are harmful to human health. In order to limit the damage, the risk analysis is of primary importance.The gas release could occur following the breakage of a pipe, which was the scenario being considered. It was analyzed using the commercial software "Phast & Safeti", an alternative tool to the methods traditionally used in the literature in hazard events of this type, such as the Threshold Limit Value-Time Weighted Average (TLV-TWA) and the Threshold Limit Value-Short Term Exposure Limit (TLV-STEL), that are defined on the basis of the characteristics of the substance dispersed in the air.Since the pressure of the extraction vessel...
Anaerobic digestion is a technology used to biologically convert organic substrates into biogas i... more Anaerobic digestion is a technology used to biologically convert organic substrates into biogas in the absence of oxygen. The resulting biogas is a renewable energy source mainly consisting of a mixture of methane (60÷70% v/v) and carbon dioxide (30÷40% v/v), with traces of some minor compounds, such as H2S and NH3. Anaerobic digestion takes place through a sequence of four biological phases - hydrolysis, acidogenesis, acetogenesis, and methanogenesis - performed by the action of particular species of bacteria. Operating parameters such as temperature, pH, pressure and organic substrates govern the process and affect the starting biomass transformation and the content of methane into the biogas. The biogas from anaerobic digestion can be upgraded to biomethane by removing CO2 and the minor compounds. The techniques commonly used for this purpose, like pressure swing adsorption and membrane separation, are energy-intensive as they require the compression of biogas. In this paper, an ...
The aim of this study was to develop an effective integrated cultivation system for Haematococcus... more The aim of this study was to develop an effective integrated cultivation system for Haematococcus pluvialis as a source of bioactive compounds such as astaxanthin, lutein, proteins, and fatty acids (FAs). The Chlorophyta H. pluvialis was cultivated in a vertical bubble column photobioreactor (VBC-PBR) under batch mode, allowing switching from green to red phase for astaxanthin induction. The combined effect of light intensity and nutrients on bioactive compound formation was investigated. Results showed that growth under lower nutrients availability and light intensity led to a higher concentration of biomass. Growth under high light intensity with an appropriate concentration of nitrate, sulfate, phosphate and magnesium led to ~85% and ~58% higher production of total carotenoids and fatty acids, respectively. Under high stress conditions, ~90% nitrate and phosphate consumption were observed.
Several bacteria pathogens are responsible for plant diseases causing significant economic losses... more Several bacteria pathogens are responsible for plant diseases causing significant economic losses. The antibacterial activity of Dunaliella salina microalgae extracts were investigated in vitro and in vivo. First, biomass composition was chemically characterized and subjected to extraction using polar/non-polar solvents. The highest extraction yield was obtained using chloroform:methanol (1:1 v/v) equal to 170 mg g−1 followed by ethanol (88 mg g−1) and hexane (61 mg g−1). In vitro examination of hexane extracts of Dunaliella salina demonstrated antibacterial activity against all tested bacteria. The hexane extract showed the highest amount of β-carotene with respect to the others, so it was selected for subsequent analyses. In vivo studies were also carried out using hexane extracts of D. salina against Pseudomonas syringae pv. tomato and Pectobacterium carotovorum subsp. carotovorum on young tomato plants and fruits of tomato and zucchini, respectively. The treated young tomato pla...
Haematococcus pluvialis microalgae is a promising source of astaxanthin, an excellent antioxidant... more Haematococcus pluvialis microalgae is a promising source of astaxanthin, an excellent antioxidant carotenoid. H. pluvialis, as well as other species, could find more extensive applications as healthy food for a variegated carotenoids composition in addition to astaxanthin. Official method has not currently been used for this purpose. The objective of this work was to propose a method to characterize carotenoids in H. pluvialis after the comparison between spectrophotometric and liquid chromatography analysis. In addition, in order to improve the use of astaxanthin in the food industry, thermal stability was investigated. In this context, the effect of temperature at 40–80 °C, over a 16 h storage period was tested on astaxanthin produced by H. pluvialis. A further test was carried out at room temperature (20 °C) for seven days. A decrease in the astaxanthin concentration was observed at all tested temperatures with a decrease >50% of all-trans isomer at 80 °C after 16 h and an inc...
The present study aimed to develop an integrated treatment of agro-industrial waste for biofuel (... more The present study aimed to develop an integrated treatment of agro-industrial waste for biofuel (biogas and syngas) production and for phosphorus recovery. In the first step, an anaerobic digestion (AD) process was carried out on two different mixtures of raw agro-industrial residues. Specifically, a mixture of asparagus and tomato wastes (mixture-1) and a mixture of potatoes and kiwifruit residues (mixture-2) were investigated. The results proved that the properties of mixtures notably affect the evolution of the digestion process. Indeed, despite the lower organic load, the maximum biogas yield, of about 0.44 L/gCODremoved, was obtained for mixture-1. For mixture-2, the digestion process was hindered by the accumulation of acidity due to the lack of alkalinity in respect to the amount of volatile fatty acids. In the second step, the digestates from AD were utilized for syngas production using supercritical water gasification (SCWG) at 450 °C and 250 bar. Both the digestates were r...
In this article, microalgae Nannochloropsis sp. was used for fatty acid (FA) extraction, using a ... more In this article, microalgae Nannochloropsis sp. was used for fatty acid (FA) extraction, using a supercritical fluid-carbon dioxide (SF-CO2) extraction method. This study investigated the influence of different pre-treatment conditions by varying the grinding speed (200–600 rpm), pre-treatment time (2.5–10 min), and mixing ratio of diatomaceous earth (DE) and Nannochloropsis sp. biomass (0.5–2.0 DE/biomass) on FAs extraction. In addition, the effect of different operating conditions, such as pressure (100–550 bar), temperature (50–75 °C), and CO2 flow rate (7.24 and 14.48 g/min) on eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) recovery, was analyzed. Experimental data evidenced that, keeping constant the extraction conditions, the pre-treatment step enhanced the FAs extraction yield up to 3.4 fold, thereby the maximum extracted amount of FAs (61.19 mg/g) was attained with the pre-treatment with a ratio of DE/biomass of 1 at 600 rpm for 5 min. Moreover, by increasing bot...
This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology fo... more This research shows that carbon dioxide supercritical fluid (CO2-SF) is an emerging technology for the extraction of high interest compounds for applications in the manufacturing of pharmaceuticals, nutraceuticals, and cosmetics from microalgae. The purpose of this study is to recover fatty acids (FAs) and, more precisely, eicosapentaenoic acid (EPA) from Nannochloropsis gaditana biomass by CO2-SF extraction. In the paper, the effect of mechanical pre-treatment was evaluated with the aim of increasing FAs recovery. Extraction was performed at a pressure range of 250–550 bars and a CO2 flow rate of 7.24 and 14.48 g/min, while temperature was fixed at 50 or 65 °C. The effect of these parameters on the extraction yield was assessed at each extraction cycle, 20 min each, for a total extraction time of 100 min. Furthermore, the effect of biomass loading on EPA recovery was evaluated. The highest EPA extraction yield, i.e., 11.50 mg/g, corresponding to 27.4% EPA recovery, was obtained at ...
Microalgae Dunaliella salina contains useful molecules such as β-carotene and fatty acids (FAs), ... more Microalgae Dunaliella salina contains useful molecules such as β-carotene and fatty acids (FAs), which are considered high value-added compounds. To extract these molecules, supercritical carbon dioxide was used at different operative conditions. The effects of mechanical pre-treatment (grinding speed at 0–600 rpm; pre-treatment time of 2.5–7.5 min) and operating parameters for extraction, such as biomass loading (2.45 and 7.53 g), pressure (100–550 bars), temperature (50–75 °C) and CO2 flow rate (7.24 and 14.48 g/min) by varying the extraction times (30–110 min) were evaluated. Results showed that the maximum cumulative recovery (25.48%) of β-carotene was achieved at 400 bars and 65 °C with a CO2 flow rate of 14.48 g/min, while the highest purity for stage (55.40%) was attained at 550 bars and 65 °C with a CO2 flow rate of 14.48 g/min. The maximum recovery of FAs, equal to 8.47 mg/g, was achieved at 550 bars and 75 °C with a CO2 flow rate of 14.48 g/min. Moreover, the lowest biomas...
Photocatalysis combined with membrane technology could offer an enormous potential for power gene... more Photocatalysis combined with membrane technology could offer an enormous potential for power generation in a renewable and sustainable way. Herein, we describe the one-step hydrogen and oxygen evolution through a photocatalytic membrane reactor. Experimental tests were carried out by means of a two-compartment cell in which a modified Nafion membrane separated the oxygen and hydrogen evolution semi-cells, while iron ions permeating through the membrane acted as a redox mediator. Nanosized Au/TiO2 and Au/CeO2 were employed as suspended photocatalysts for hydrogen and oxygen generation, respectively. The influence of initial Fe3+ ion concentration, ranging from 5 to 20 mM, was investigated, and the best results in terms of hydrogen and oxygen evolution were registered by working with 5 mM Fe3+. The positive effect of gold on the overall water splitting was confirmed by comparing the photocatalytic results obtained with the modified/unmodified titania and ceria. Au-loading played a key...
The production of biofuels from renewable sources is a major challenge in research. Methanol, eth... more The production of biofuels from renewable sources is a major challenge in research. Methanol, ethanol, dimethyl ether (DME), synthetic natural gas (SNG), and hydrogen can be produced from syngas which is the result of the gasification of biomasses. Syngas composition varies according to the gasification technology used (such as fixed bed reactors, fluidized bed reactors, entrained flow reactors), the feedstock characteristics, and the operating parameters. This paper presents a review of the predominant biomass gasification technologies and biofuels obtained from syngas by biomass gasification.
Thermal analysis of olive tree pruning and the by-products obtained by its gasification and pyrol... more Thermal analysis of olive tree pruning and the by-products obtained by its gasification and pyrolysis: The effect of some heavy metals on their devolatilization behavior
Astaxanthin and lutein, antioxidants used in nutraceutics and cosmetics, can be extracted from se... more Astaxanthin and lutein, antioxidants used in nutraceutics and cosmetics, can be extracted from several microalgal species. In this work, investigations on astaxanthin and lutein extraction from Haematococcus pluvialis (H. pluvialis) in the red phase were carried out by means of the supercritical fluid extraction (SFE) technique, in which CO2 supercritical fluid was used as the extracting solvent with ethanol as the co-solvent. The experimental activity was performed using a bench-scale reactor in semi-batch configuration with varying extraction times (20, 40, 60, and 80 min), temperatures (50, 65, and 80 °C) and pressures (100, 400, and 550 bar). Moreover, the performance of CO2 SFE with ethanol was compared to that without ethanol. The results show that the highest astaxanthin and lutein recoveries were found at 65 °C and 550 bar, with ~18.5 mg/g dry weight (~92%) astaxanthin and ~7.15 mg/g dry weight (~93%) lutein. The highest astaxanthin purity and the highest lutein purity were ...
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Papers by Antonio Molino