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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 selected as natural producer of EPA. The extract obtained after ScCO2 tests was enriched of EPA and protein, therefore suitable for food applications. The exhausted biomass, having a high content of carbohydrates and total dietary fiber, might be proposed as feed supplement.

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 production whose content is around 4.5 mg/g dry weight. The aim of this paper is to improve lutein extraction from Scenedesmus almeriensis by using pressurized liquid extraction through accelerated solvent extractor (ASE 200©Dionex). Extractions were performed using different solvent as the mixture chloroform:methanol (1:1 v/v), ethanol, hexane, acetone. Several temperatures were tested from 20° to 80°C and biomass was mechanically pre-treated. Each extraction cycle was repeated until to complete biomass decolouring.

The growing consciousness for environmental issues have stimulated the search for more sustainable biochemical processes. One of the most attracting chemicals with enormous potential in a biobased economy is succinic acid (SA, butanedioic acid or 1, 2-ethanedicarboxylic acid). This compound represents the chemical building block for various high value-added substances which find applications in the detergent/surfactant, food, ion chelator and pharmaceutical markets. Nowadays, the SA market is estimated to be about 20000-30000 ton per year worldwide and its industrial manufacture is mainly based on the catalytic hydrogenation of petrochemically derived maleic acid or maleic anhydride. However, since SA is fermentative product and an intermediate of several biochemical pathways, including the tricarboxylic acid cycle, it can be produced by many microorganisms. The biological SA production at commercial scale and potentially for the commodity chemical market is still a challenging target and requires the development and the optimization of microorganisms-based processes able to guarantee high product concentrations to justify economically feasible recovery. The aim of this paper is the conversion of a mixture of sugars, mainly containing glucose, into SA by SA-producing strain Actinobacillussuccinogens, that was isolated from the bovine rumen. It is a facultative anaerobic, pleomorphic, Gram-negative rod. Experimental tests were carried out by using Actinobacillussuccinogens bought by Culture Collection of Goteborg and by using TBS (Tryptic Soy broth) by changing the concentration of glucose as well as that of other sugars as fructose, xylose, sucrose with the main focus to evaluate the effect of the fermentation for the Actinobacillussuccinogens with the single sugars in a concentration range from 1 to 15 g/l. All the experiments were carried out in anaerobic conditions at 37°C and in a pH range 7-8 for several days. For each test, carboxylic acids and sugars were analyzed by using u-HPLC while the growth of the selected microorganism was monitored by means of a spectrophotometer at 600nm for OD tests.

The present work reports the results of the experiment on long term evaluation of 18 genotypes of Switchgrass at field level under the climatic conditions of South Italy. The main purpose of this work was to study the cultivation techniques and evaluate other than the biomass productivity also the adaptability of Switchgrass varieties (upland and lowland ones) for a long period of time under Mediterranean climate. © 2008, Page Press Publications. All rights reserved.

Sweet sorghum (Sorghum bicolor (L.) Moench) is a drought tolerant energy crop, with a high nitrogen use efficiency, identified as a possible ethanol feedstock because of its biomass yield and high concentration of fermentable free sugars. The cultivation of sweet sorghum is easy and economic, and it could be an alternative in particular regions where conditions are not favorable for growing starch-rich crops, such as maize. Bagasse and stillage are the main by-products of the sweet sorghum processing for bioethanol production and become useful raw materials for further bio-production, such as lignocellulosic fuels, biogas and 2nd generation bioethanol. In its poor post-harvest storage characteristics and in the seasonally availability, sweet sorghum found the main disadvantages. The project MULTISORGO wants to exploit the advantages of sweet sorghum as potential energy crop for bio­energy production. Thereby, the main objective of MULTISORGO is to optimize all the single steps of the bioethanol production chain starting from sweet sorghum biomass, focusing on the sugar preservation during the storage and the by-product energetic exploitation for different biofuels production. The final aim is to propose an EU sustainable model for the biofuel production in decentralised plants using a promising crop, also considering the RES directive restrictions., Proceedings of the 19th European Biomass Conference and Exhibition, 6-10 June 2011, Berlin, Germany, pp. 1905-1912

Accelerated solvent extraction (ASE) was used for the extraction of carotenoids from pre-treated biomass of Dunaliella salina microalgae. The total carotenes and lutein were extracted using different solvents i.e., acetone, chloroform: methanol (C:M) in the ratio of 1:1, ethanol, and hexane. The effects of various experimental parameters, such as temperature (20, 40, 60 and 80 °C), pressure (50 and 100 bar) and static time (2 cycles of 5 and 10 minutes) on the ASE extraction efficiency were investigated systematically. The properties of the solvent and the extraction temperature were found to be the most important parameters affecting the ASE extraction efficiency of thermolabile natural compounds. Moreover, 99% recovery of total carotenes was achieved during extraction with hexane solvent at 40 °C, 100 bar and 2 cycle of 10 minutes. While solvent mixture of C:M was suitable for lutein extraction and resulted 92% recovery at 20 °C, 100 bar and 2 cycle of 10 minutes., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 112-118

Microalgae are a rich source of natural bioactive compounds, e.g. astaxanthin, β-carotene, lutein, and fatty acids (FAs), that are currently in high demand in the market. Conventional extraction methods often produce adverse effects on some of these compounds. Replacing conventional extraction methods with more efficient advanced green technologies that offer greater extracts purity and low environmental impact is therefore a challenging and sought-for target. This review is a comprehensive overview of supercritical fluid (SCF) extraction processes, including the latest research on the extraction of bioactive compounds from microalgae biomass and their benefits on human health. In addition, the role of key operating parameters on the selectivity of various compounds is discussed. This study provides useful knowledge that can productively contribute to the future development of SCF-based extraction technologies on an industrial scale.

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&minus, 1 followed by ethanol (88 mg g&minus, 1) and hexane (61 mg g&minus, 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 &beta, 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 plants exhibited a reduction of 65.7% incidence and 77.0% severity of bacterial speck spot disease. Similarly, a reduction of soft rot symptoms was observed in treated tomato and zucchini fruits with a disease incidence of 5.3% and 12.6% with respect to 90.6% and 100%, respectively, for the positive control.

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&ndash, 600 rpm), pre-treatment time (2.5&ndash, 10 min), and mixing ratio of diatomaceous earth (DE) and Nannochloropsis sp. biomass (0.5&ndash, 2.0 DE/biomass) on FAs extraction. In addition, the effect of different operating conditions, such as pressure (100&ndash, 550 bar), temperature (50&ndash, 75 &deg, 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 both SF-CO2 pressure and temperature, the selectivity towards EPA was enhanced, while intermediate pressure and lower pressure promoted DHA recovery. The highest amount of extracted EPA, i.e., 5.69 mg/g, corresponding to 15.59%, was obtained at 75 &deg, C and 550 bar with a CO2 flow rate of 14.48 g/min, while the maximum amount of extracted DHA, i.e., ~0.12 mg/g, equal to 79.63%, was registered at 50 &deg, C and 400 bar with a CO2 flow rate of 14.48 g/min. Moreover, the increased CO2 flow rate from 7.24 to 14.48 g/min enhanced both EPA and DHA recovery.

Haematococcus pluvialis microalgae in the red phase can produce significant amounts of astaxanthin, lutein, and fatty acids (FAs), which are valuable antioxidants in nutraceutics and cosmetics. Extraction of astaxanthin, lutein, and FAs from disrupted biomass of the H. pluvialis red phase using carbon dioxide (CO2) in supercritical fluid extraction (SFE) conditions was investigated using a bench-scale reactor in a semi-batch configuration. In particular, the effect of extraction time (20, 40, 60, 80, and 120 min), CO2 flow rate (3.62 and 14.48 g/min) temperature (50, 65, and 80 &deg, C), and pressure (100, 400, and 550 bar.) was explored. The results show the maximum recovery of astaxanthin and lutein achieved were 98.6% and 52.3%, respectively, at 50 &deg, C and 550 bars, while the maximum recovery of FAs attained was 93.2% at 65 &deg, C and 550 bars.

Citrus × limon cv. Femminello Comune (Rutaceae) from Rocca Imperiale (Italy), one of the six Protected Geographical Indication (PGI) Italian lemon crops, has been recently received renewed interest. In this work, fresh and dried peels and leaves were extracted by hydrodistillation, supercritical fluid extraction (SFE), and Soxhlet apparatus. Chemical profile was assessed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Except for leaves extracts obtained by Soxhlet apparatus, the monoterpene hydrocarbons fraction dominated. Limonene, γ-terpinene, and β-pinene were the main identified compounds. The antioxidant activity was investigated using different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS, ferric reducing ability power (FRAP), and β-carotene bleaching test. In DPPH test, the essential oil obtained by hydrodistillation of fresh peel exhibited the highest activity (IC50 of 1.17 mg/ml). Leaves extracted by SFE showed a good activity in both DPPH and β-carotene bleaching test with IC50 values of 2.20 and 6.66 mg/ml, respectively. Monoterpene hydrocarbons fraction exhibited a positive Pearson's correlation coefficient with all antioxidant assays. Leaves, often considered waste material, should be considered from a different point because they represent a matrix of indisputable interest. © 2016 Verlag Helvetica Chimica Acta AG, Zürich.