Loading...
8 results
Search Results
Now showing 1 - 8 of 8
- Review of sewage sludge as a soil amendment in relation to current international guidelines: a heavy metal perspectivePublication . Nunes, Nuno; Ragonezi, Carla; Gouveia, Carla S. S.; Carvalho, Miguel Â. A. Pinheiro deOverexploitation of resources makes the reutilization of waste a focal topic of modern society, and the question of the kind of wastes that can be used is continuously raised. Sewage sludge (SS) is derived from the wastewater treatment plants, considered important underused biomass, and can be used as a biofertilizer when properly stabilized due to the high content of inorganic matter, nitrate, and phosphorus. However, a wide range of pollutants can be present in these biosolids, limiting or prohibiting their use as biofertilizer, depending on the type and origin of industrial waste and household products. Long-term applications of these biosolids could substantially increase the concentration of contaminants, causing detrimental effects on the environment and induce hyper accumulation or phytotoxicity in the produced crops. In this work, some critical parameters for soils and SS agronomic use, such as organic matter, nitrogen, phosphorous, and potassium (NPK), and heavy metals concentration have been reviewed. Several cases of food crop production and the accumulation of heavy metals after SS application are also discussed. SS production, usage, and legis lation in EU are assessed to determine the possibility of sustainable management of this bioresource. Additionally, the World Health Organization (WHO) and Food and Agriculture Organization (FAO) guidelines are addressed. The opportunity to produce bioenergy crops, employing sewage sludge to enhance degraded land, is also considered, due to energy security. Although there are numerous advantages of sewage sludge, proper screening for heavy metals in all the variants (biosolids, soil, food products) is a must. SS application requires appropriate strict guidelines with appropriate regulatory oversight to control contamination of agricultural soils.
- Evaluation of the use of marine macroalgae in the industrial production of biorefinery-derived biofunctional productsPublication . Nunes, Nuno Miguel Velosa; Carvalho, Miguel Ângelo Almeida Pinheiro de; Barreto, Maria do Carmo Roque Lino FelgueirasA tese de doutoramento aqui apresentada integra a avaliação da composição bioquímica de várias espécies de macroalgas, prospetadas no arquipélago da Madeira e arrojamentos de macroalgas provenientes de Gran Canária com o objetivo principal de determinar a potencialidade destes recursos em integrar estratégias de biorefinaria. Esta metodologia é extremamente importante para a gestão sustentável de recursos e mitigação dos impactos, promovidos pela indústria tradicional e pela exploração intensiva dos recursos naturais, desenvolvendo modelos dinâmicos, lucrativos e confiáveis. Este trabalho está dividido em três capítulos, integrando uma introdução geral, um capítulo composto por artigos científicos e um terceiro capítulo que incorpora uma discussão, conclusão e perspetivas futuras. O capítulo 2 começa por abordar uma análise morfológica em 3 macroalgas, por forma a compreender o seu ciclo biológico. Integra 2 artigos que descrevem a variabilidade bioquímica, nutricional e antioxidante e adicionalmente outros 2 artigos que abordam a avaliação da quantidade de iodo e fucoxantina com precisão, biocompostos de extrema importância económica e nutracêutica, no qual foram desenvolvidas e validadas novas metodologias analíticas para uma rápida análise destes compostos nesta biomassa. A implementação de estratégias de biorefinaria foram conduzidas em 2 macroalgas, A. taxiformis e Z. tournefortii. Na primeira foram utilizados 4 solventes e 2 metodologias para a extração primária de um composto bioativo, efetuando posteriormente a extração sequencial de lípidos, carragenanas e celulose do resíduo remanescente. Para a segunda, foi utilizado 1 solvente, utilizando o extrator Timatic em conjunto com um modelo estatístico por forma a modelar e otimizar a extração de um composto bioativo, extraindo subsequente do resíduo fucoidano e celulose. Adicionalmente, foi efetuada a avaliação da composição dos ácidos gordos em 3 macroalgas coletadas no arquipélago da Madeira, efetuado uma avaliação por TLC, ATR-FTIR, atividade anticolinesterásica e citotoxicidade in vitro na linhagem de células tumorais A549.
- Encapsulation with Natural Polymers to Improve the Properties of Biostimulants in AgriculturePublication . Jiménez-Arias, David; Morales-Sierra, Sarai; Silva, Patrícia; Carrêlo, Henrique; Gonçalves, Adriana; Ganança, José Filipe Teixeira; Nunes, Nuno; Gouveia, Carla S. S.; Alves, Sónia; Borges, João Paulo; Carvalho, Miguel Â. A. Pinheiro deEncapsulation in agriculture today is practically focused on agrochemicals such as pes ticides, herbicides, fungicides, or fertilizers to enhance the protective or nutritive aspects of the entrapped active ingredients. However, one of the most promising and environmentally friendly technologies, biostimulants, is hardly explored in this field. Encapsulation of biostimulants could indeed be an excellent means of counteracting the problems posed by their nature: they are easily biodegradable, and most of them run off through the soil, losing most of the compounds, thus becoming inaccessible to plants. In this respect, encapsulation seems to be a practical and profitable way to increase the stability and durability of biostimulants under field conditions. This review paper aims to provide researchers working on plant biostimulants with a quick overview of how to get started with encapsulation. Here we describe different techniques and offer protocols and suggestions for introduction to polymer science to improve the properties of biostimulants for future agricultural applications.
- Pharmacological and cosmeceutical potential of Seaweed Beach-Casts of MacaronesiaPublication . Zárate, Rafael; Portillo, Eduardo; Teixidó, Sílvia; Carvalho, Miguel A. A. Pinheiro de; Nunes, Nuno; Ferraz, Sónia; Seca, Ana M. L.; Rosa, Gonçalo P.; Barreto, Maria CarmoSeaweed beach-casts are a seasonal phenomenon that regularly deposits tons of algae biomass on beaches, which are usually disposed of in landfills. The present work aimed to contribute to the valorization of this biomass by studying bioactivities that reveal its potential in the pharmaceutical and/or cosmeceutical industries. Methanol and ethanol extracts and fractions from 15 beach-casts biomass were tested for a range of bioactivities. Eight of the most active samples exhibit IC50 values between 11.38 µg/mL and 19.28 µg/mL and selectivity indexes higher than 3.8, against NCI-H1299 (lung cancer) and T47D (breast cancer). Concerning antiaging potential, all the extracts tested presented UV protection, with SPF values above 30, like the standard sunscreen. Regarding aging-related enzymes, 24 samples were tyrosinase inhibitors exhibiting IC50 values from 9.01 µg/mL to 200.09 µg/mL. Eight extracts inhibited collagenase (IC50 < 248.76 µg/mL), two of them more actively than positive control EDTA (IC50 = 59.26 µg/mL). In addition to UV protection, the cumulative effect of antityrosinase and anticollagenase activities shown by the samples suggest that they may play a significant role in preventing skin photoaging. The results obtained demonstrate the high potential of beach-cast seaweed biomass as sources of cosmetic bioproducts with antiaging effects, and of selective cytotoxic metabolites.
- Sewage sludge fertilization—A case study of Sweet Potato yield and heavy metal accumulationPublication . Ragonezi, Carla; Nunes, Nuno; Oliveira, Maria Cristina O.; Freitas, José G. R. de; Ganança, José Filipe T.; Carvalho, Miguel Â. A. Pinheiro deSewage sludge (SS) is derived from wastewater treatment plants and can be used as a biofertilizer when properly stabilized. This work aimed to evaluate SS application for agricultural production improvement. SS was tested on Porto Santo Island (Portugal). The experiment was randomly designed with three 25 m2 plots for each treatment (2 SS concentrations + control without SS) and performed in two consecutive cycles. For the first cycle, dehydrated sludge was mixed with soil, obtaining final concentrations of 0.8 kg/m2 (C1) and 1.6 kg/m2 (C2). Half of the concentration was used for the second cycle. Fifty-eight sweet potato plants were used in each plot. SS application boosted the agronomic parameters of biomass, productivity, and shoot biomass. Furthermore, improvements in soil properties were observed, mainly for pH, CEC, and NO3 -N, with no significant increase in heavy metals. For the edible parts, heavy metal concentrations decreased, and Pb was the only one that still exceeded the maximum limits. The results demonstrated that SS application to low-fertility soil is effective in improving the agronomic parameters of sweet potato and enhancing soil features. Further studies considering other variables, i.e., SS origin, soil properties, and the crop, must be carried out to propose custom applications.
- From a heavy metal perspective, is macroalgal biomass from Madeira Archipelago and Gran Canaria Island of eastern Atlantic safe for the development of blue bioeconomy products?Publication . Nunes, Nuno; Ferraz, Sónia; Venuleo, Marianna; Barros, Ana I. R. N. A.; Carvalho, Miguel A. A. Pinheiro deMacroalgae are considered a valuable source of several compounds with nutritional, nutraceutical, cosmeceutical, and phar maceutical applications. They are also used for crop fertilization and biofortifcation by introducing important minerals into the soil essential for crop productivity. At the same time, however, they are known bio-accumulators of some heavy metals. In this work, we assessed the content of 7 minerals considered as heavy metals in 25 macroalgae samples, comprising 4 greens, 9 reds and 12 browns, from Madeira Archipelago, Portugal, for their potential use as blue bioeconomy products. These heavy metals included zinc (Zn) with concentrations that ranged from 1.95 – 242.65 mg kg−1 dw, nickel (Ni, 0.6 – 34.78 mg kg−1 dw), copper (Cu, 0.42 – 7.98 mg kg−1 dw), chromium (Cr, 0.47 – 45.74 mg kg−1 dw), cadmium (Cd, 0.1 – 2.58 mg kg−1 dw), lead (Pb, 0.05 – 2.79 mg kg−1 dw) and mercury (Hg, 0.03 – 8.49 µg kg−1 dw). We also analysed 22 samples of beach-cast macroalgae from Gran Canaria Island, Spain, collected from November 2016 to November 2019. The same heavy metals were assessed with their concentrations that ranged as follows: Zn (11.41 – 42.20 mg kg−1 dw), Ni (3.17 – 17.78 mg kg−1 dw), Cu (1.85 – 4.20 mg kg−1 dw), Cr (6.08 – 37.98 mg kg−1 dw), Cd (0.02 – 0.11 g kg−1 dw), Pb (0.16 –5.42 mg kg−1 dw) and Hg (3.59 – 31.00 µg kg−1 dw). These concentrations are all within the normal ranges reported in earlier studies in low industrialized areas, except for the brown algae Gongolaria abies-marina and Sargassum vulgare with high mean (±SD) Cd concentration (1.91±0.36 and 1.75±0.07 g kg−1 dw respectively). Our results suggest that most of the biomass prospected in these localities covered in the present study would be a viable source of materials for the development of a blue economy industry with emerging products following the European Union directives.
- Biochemical study of attached macroalgae from the Madeira Archipelago and beach-cast macroalgae from the Canary Islands: multivariate analysis to determine bioresource potentialPublication . Nunes, Nuno; Valente, Sofia; Ferraz, Sónia; Barreto, Maria Carmo; Carvalho, Miguel Â. A. Pinheiro deFifteen attached macroalgae from the Madeira Archipelago, comprising three green, three red and nine brown algal species, as well as two beach-cast macroalgal samples, collected along the north shore of Gran Canaria, were assessed for their biochemical properties. The anal ysis included the determination of total minerals, total carbohydrates, protein, lipids, chlorophyll a, total carote noids, total phenolic content, fucoxanthin and phycobilins (allophycocyanin, phycocyanin and phycoerythrin). The results showed a high variability of biochemical composi tion, allowing for the targetting of specific bioresources for particular purposes, including functional foods. This work provides the foundation for a biorefinery strategy implementation plan, for which specific macroalgae may be tar geted for valuable and beneficial compounds
- Protein extracts from microalgae and cyanobacteria biomass. Techno-functional properties and bioactivity: a reviewPublication . Nunes, Emmanuel; Odenthal, Kilian; Nunes, Nuno; Fernandes, Tomásia; Fernandes, Igor A.; Carvalho, Miguel A. A. Pinheiro de; Nunes, Nuno; Fernandes, TomásiaMicroalgae and cyanobacteria are photosynthetic and unicellular organisms that contain considerable amounts of proteins, lipids, carbohydrates, and polyunsaturated fatty acids, among others, with applications in the cosmetic, pharmaceutical, and food industries. These microorganisms can accumulate protein up to 70 % of total biomass depending on the microalgal strain, hence they have been regarded as an alternative protein source for the future. Microalgal proteins have important applications such as emulsifying, foaming, and gelation prop erties, which are important for the determination of quality and texture of foods. Some microalgal peptides possess important bioactivity with many health-benefit effects. Therefore, to maximize the production of proteins from microalgae and cyanobacteria, many protein extraction procedures have been studied to increase the economic return. They have been tested towards higher protein yields at low energy cost, the preservation of protein native properties, and lower cell debris. This later is fundamental to facilitate the subsequent purification processes so that the overall cost can be reduced. The aim of this work is to review some cell disruption processes for the extraction of protein from microalgae and cyanobacteria, considering that this step is crucial for the overall process due to the high rigidness of microalgal cell covering, which can hamper the release of proteins. It also aims at reviewing the purification techniques after cellular disruption, from conventional to more recent approaches, and finally addresses the antioxidant, antidiabetic, antihypertensive, antibacterial and other bioactive properties of microalgal protein hydrolysates and peptides.