Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros

Bases de dados
Tipo de documento
Intervalo de ano de publicação
1.
Food Funct ; 15(10): 5554-5565, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38712867

RESUMO

Obesity is one of the most important threats to human health. Besides existing pharmacological or clinical interventions, novel effective and largely available solutions are still necessary. Among diverse natural resources, microalgae are well known for their complexity in the production of novel secondary metabolites. At the same time, lactic acid bacteria (LAB) are known for their capacity to metabolize, through fermentation, different matrices, and consequently to modify or produce new compounds with potential bioactivity. This work aimed to study the production of fermented microalgae and cyanobacteria, and to analyse their extracts in the zebrafish Nile red fat metabolism assay. Three microalgal species (Chlorella vulgaris, Chlorococcum sp. and Arthrospira platensis) were fermented with seven strains of LAB from 4 species (Lacticaseibacillus rhamnosus, Lacticaseibacillus casei, Lactobacillus delbrueckii bulgaricus and Lacticaseibacillus paracasei), derived from the UPCCO - University of Parma Culture Collection, Parma, Italy). All the selected strains were able to ferment the selected species of microalgae, and the most suitable substrate for LAB growth was Arthrospira platensis. Extracts from fermented Chlorella vulgaris and Chlorococcum sp. reduced significantly the neutral lipid reservoirs, which was not observed without fermentations. The strongest lipid reducing effect was obtained with Arthrospira platensis fermented with Lactobacillus delbrueckii bulgaricus 1932. Untargeted metabolomics identified some compound families, which could be related to the observed bioactivity, namely fatty acids, fatty amides, triterpene saponins, chlorophyll derivatives and purine nucleotides. This work opens up the possibility of developing novel functional foods or food supplements based on microalgae, since lactic acid fermentation enhanced the production of bioactive compounds with lipid reducing activities.


Assuntos
Fermentação , Metabolismo dos Lipídeos , Metabolômica , Microalgas , Peixe-Zebra , Animais , Microalgas/metabolismo , Microalgas/química , Ácido Láctico/metabolismo , Cianobactérias/metabolismo , Lactobacillales/metabolismo , Oxazinas , Spirulina
2.
Bioresour Technol ; 387: 129620, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37544540

RESUMO

Microalgae are promising organisms that are rapidly gaining much attention due to their numerous advantages and applications, especially in biorefineries for various bioenergy and biochemicals. This review focuses on the microalgae contributions to Bio-Circular-Green (BCG) economy, in which zero-waste approaches for sustainable production and biorefineries of microalgal biomass are introduced and their possible integration is discussed. Firstly, overviews of wastewater upcycling and greenhouse gas capture by microalgae are given. Then, a variety of valuable products from microalgal biomass, e.g., pigments, vitamins, proteins/peptides, carbohydrates, lipids, polyunsaturated fatty acids, and exopolysaccharides, are summarized to emphasize their biorefinery potential. Techno-economic and environmental analyses have been used to evaluate sustainability of microalgal biomass production systems. Finally, key issues, future perspectives, and challenges for zero-waste microalgal biorefineries, e.g., cost-effective techniques and innovative integrations with other viable processes, are discussed. These strategies not only make microalgae-based industries commercially feasible and sustainable but also reduce environmental impacts.


Assuntos
Microalgas , Microalgas/química , Biomassa , Conservação de Recursos Energéticos , Biocombustíveis , Águas Residuárias
3.
An Acad Bras Cienc ; 94(4): e20201735, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35830071

RESUMO

The environmental and health risks associated with the application of synthetic chemical inputs in agriculture increased the demand for technologies that allow higher performance and quality of vegetable crops by implementing synergistic materials with the principles of sustainability. In this work, the seed coating with the biomass of Dunaliella salina incorporated in a bioplastic film of Manihot esculenta (cassava) was evaluated as an initial growth and secondary compounds stimulator of Coriandrum sativum (coriander) plants. The obtained results demonstrated that the coating stimulated an increase in the germination percentage (28.75%) and also in concentration of bioactive compounds, such as the six-fold increment of caffeic acid (13.33 mg 100 g-1). The carbohydrates, lipids, and proteins present in the microalgae biomass seem to be responsible for these increments once they are known for providing energy to the seedling development and coordinating the secondary metabolites synthesis. As conclusion, we consider the coating with biomass of D. salina an alternative for crop improvement that contributes to the development of sustainable agricultural practices.


Assuntos
Biomassa , Clorofíceas , Coriandrum , Microalgas , Desenvolvimento Vegetal , Metabolismo Secundário , Sementes , Ácidos Cafeicos , Carboidratos , Clorofíceas/química , Coriandrum/química , Coriandrum/efeitos dos fármacos , Coriandrum/crescimento & desenvolvimento , Coriandrum/metabolismo , Produção Agrícola/métodos , Lipídeos , Manihot/química , Microalgas/química , Desenvolvimento Vegetal/efeitos dos fármacos , Metabolismo Secundário/efeitos dos fármacos , Sementes/química , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Desenvolvimento Sustentável
4.
Braz J Microbiol ; 52(4): 1779-1790, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34510399

RESUMO

Microalgae cultivation for exopolysaccharide production has getting more attention as a result of their high hydrocarbon biosynthesis skill. The aim of this study is to examine the exopolysaccharide production potential of different species of microalgae. In this context, exopolysaccharides were produced from Chlorella minutissima, Chlorella sorokiniana and Botryococcus braunii microalgae and the effects of carbon and nitrogen content in the growth medium and illumination time on exopolysaccharide production were analyzed statistically using Box-Behnken experimental design. In addition, techno-economic assessment of exopolysaccharide production were also performed by using the most productive microalgae and optimum conditions determined in this study. As a result of the experiments, it was seen that C. minutissima, C. sorokiniana and B. braunii produced 0.245 ± 0.0025 g/L, 0.163 ± 0.0016 g/L and 0.117 ± 0.0007 g/L exopolysaccharide, respectively. Statistically, it was observed that there was an inverse relationship between the exopolysaccharide production and investigated parameters such as illumination period and carbon and nitrogen amounts of culture mediums. The techno-economic assessment comprising microalgal exopolysaccharide (EPS) bioprocess was carried out, and it showed that the system can be considered economically viable, yet can be improved with biorefinery approach.


Assuntos
Microalgas , Polissacarídeos , Biomassa , Carbono/análise , Meios de Cultura/química , Microbiologia Industrial/economia , Microalgas/química , Nitrogênio/análise , Polissacarídeos/biossíntese , Polissacarídeos/química
5.
Molecules ; 25(15)2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32731380

RESUMO

Microalgae productive chains are gaining importance as sustainable alternatives to obtain natural pigments. This work presents a review on the most promising pigments and microalgal sources by gathering trends from a 10-year bibliometric survey, a patents search, and an industrial and market analysis built from available market reports, projects and companies' webpages. The performed analysis pointed out chlorophylls, phycocyanin, astaxanthin, and ß-carotene as the most relevant pigments, and Chlorella vulgaris, Spirulina platensis, Haematococcus pluvialis, and Dunaliella salina, respectively, as the most studied sources. Haematococcus is referred in the highest number of patents, corroborating a high technological interest in this microalga. The biorefinery concept, investment in projects and companies related to microalgae cultivation and/or pigment extraction is increasingly growing, particularly, for phycocyanin from Spirulina platensis. These pieces of evidence are a step forward to consolidate the microalgal pigments market, which is expected to grow in the coming years, increasing the prospects of replacing synthetic pigments by natural counterparts.


Assuntos
Indústria Farmacêutica , Microalgas/química , Indústria Farmacêutica/economia , Indústria Farmacêutica/tendências , Ficocianina/química , Ficocianina/isolamento & purificação , Pigmentos Biológicos/química , Pigmentos Biológicos/economia , Pigmentos Biológicos/isolamento & purificação
6.
Carbohydr Polym ; 233: 115833, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32059886

RESUMO

Glycoscience is an interdisciplinary field, which leads to different industrial applications derived from physicochemical and/or biological properties of carbohydrates. This study aims to evaluate how glycoscience may act as a driving force to make research innovative and sustainable in industrial and/or commercial areas. To this end, we rationalized the two main properties of carbohydrate molecules into three main value chains. The regional biomass (sugar, starch, wood) value-chain exploits the physicochemical properties of carbohydrates; the glycomics explores the biological functions of carbohydrates and the non-regional biomass (microbial, pectin, chitin) value-chain exploits the two properties. Each value-chain harbors one or more niches prone to or at an emerging stage of development, and all these niches share a techno-scientific push approach aimed at developing high value-added products with new functionalities, new bioactive glycans, and new enabling technologies that will lead to new applications and possible novel therapies and diagnostics tools.


Assuntos
Carboidratos/química , Indústria Química/organização & administração , Pesquisa/organização & administração , Animais , Biomassa , Sequência de Carboidratos , Indústria Química/economia , Glicômica , Humanos , Invenções , Microalgas/química , Plantas/química , Pesquisa/economia
7.
Photosynth Res ; 142(3): 361-368, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541419

RESUMO

Chlorophyll a fluorescence is the most widely used method to study photosynthesis and plant stress. While several commercial fluorometers are available, there is a need for a low-cost and highly customisable chlorophyll fluorometer. Such a device would aid in performing high-throughput assessment of photosynthesis, as these instruments can be mass-produced. Novel investigations into photosynthesis can also be performed as a result of the user's ability to modify the devices functionality for their specific needs. Motivated by this, we present an open-source chlorophyll fluorometer based on the Kautsky induction curve (OJIP). The instrument consists of low-cost, easy-to-acquire electrical components and an open-source microcontroller (Arduino Mega) whose performance is equivalent to that of commercial instruments. Two 3D printable Open-JIP configurations are presented, one for higher plants and the other for microalgae cells in suspension. Directions for its construction are presented and the instrument is benchmarked against widely used commercial chlorophyll fluorometers.


Assuntos
Clorofila A/química , Fluorometria/instrumentação , Chlorella vulgaris/química , Desenho de Equipamento , Fluorescência , Fluorometria/métodos , Microalgas/química , Microalgas/metabolismo , Plantas/química , Plantas/metabolismo , Synechococcus/química
8.
PLoS One ; 14(9): e0221451, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31483812

RESUMO

Impact of barge movement on phytoplankton abundance and biomass was assessed in the lower stretch of river Ganga, popularly known as Bhagirathi-Hooghly river, during April 2016 to March, 2017. Based on the magnitude of tide, intensity of shipping and boating activities, the stretch from Baranagar to Lalbag (278 km), located at latitude (22°38'33.41"N to 24°10'59.75"N) and longitude (88°21'21.29"E to 88°16'5.65"E) was divided into three zones viz. zone-I (Baranagar to Barrackpore), zone II (Triveni to Balagarh) and zone III (Nabadweep to Lalbag). Water samples were collected randomly from six stations covering 22 barge movements at their passage at three different time intervals viz., 30 minutes before 'barge movement', during 'barge movement' and 30 minutes after 'barge movement'. Analysis revealed the presence of 52 phytoplankton taxa belonged to 5 phylum during the study period. The abundance of phytoplankton was highest in zone-I followed by zone III and the zone II. A 44% decrease (1,997 ±1,510 ul-1) in phytoplankton abundance was observed during 'barge movement' with respect to normal condition (3,513 ± 2,239 ul-1) which could be due to propeller turbulence in the passage. Cell damage study revealed 21% damage in phytoplankton cell structure in 'during barge' followed by 'after barge' (10%) condition compared to natural state (6%). Study revealed that phytoplankton biomass (Chlorophyll a) was influenced by 'barge movement' in the sampling stretches and the impact was assessed by one way ANOVA. The effect was found significant at Barrackpore (p <0.01), Triveni (p <0.01), Balagarh (p <0.01) and Lalbag (p <0.01) where as it was insignificant at Baranagar and Nabadweep, which may be due to continuous and existing boat trafficking at Baranagar and Nabadweep. Two way ANOVA computed using 'barge movement' and sampling stations showed significant (p<0.01) effect on magnitude of Chl a concentrations in the sampling locations. Thus, the 'barge movement' influenced phytoplankton abundance and biomass, it had a detrimental effect on phytoplankton cell architecture also. The data set of this work serves as foundation information to understand the ecological implications augmented barge induced environmental disturbances in waterways. This is the first such study which depicts the impact of 'barge movement' on aquatic food chain linkages in Bhagirathi- Hooghly river.


Assuntos
Clorofila A/análise , Fitoplâncton/metabolismo , Rios/química , Biodiversidade , Biomassa , Monitoramento Ambiental , Índia , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Fitoplâncton/química , Fitoplâncton/crescimento & desenvolvimento , Navios
9.
Asian Pac J Cancer Prev ; 20(8): 2353-2364, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450906

RESUMO

Objective: To investigate the biogenic synthesis of silver nanoparticles (AgNPs) using partially purified ethyl acetate extract of Nannochloropsis sp. hexane (EAENH) fraction of microalga. Methods: The green synthesis of AgNPs was confirmed with UV-Vis spectrum which shows the surface plasmon resonance (SPR) at 421 nm. Fourier Transform Infrared Spectra (FTIR) presented the involvement of functional groups like carboxyl groups of fatty acids, tetraterpenoids of xanthophylls, hydroxyl groups of polyphenols, carbonyl and amide linkage of proteins in the AgNP synthesis. Gas Chromatography-Mass Spectrometry analysis (GCMS) revealed that phytochemicals like octadecanoic acid and hexadecanoic acid imply in capping, bioreduction, and stabilization of AgNps. Result: High-resolution Transmission electron microscope (HRTEM), Dynamic light scattering (DLS), X-ray diffraction (XRD) and EDX analysis showed the crystalline form of the AgNPs with Z-average size 57.25 nm. The zeta potential value of -25.7 mV demonstrated the negative surface charge and colloidal stability of AgNPs. The antimicrobial activity of AgNPs displayed effective inhibition zone against selected bacterial and fungal pathogens. In vitro, antioxidant effects were assessed by 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydrogen peroxide and reducing power assays which revealed excellent scavenging potential for AgNPs than the extracts. The anti-proliferative potential of biofabricated AgNPs and extracts on Human Non-small lung cancer cell line (A549) was assessed using 3­(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) assay with IC50 values of 15 µgmL-1 and 175 µgmL-1 respectively. Conclusion: The study reveals that the microalgae-mediated AgNPs possesses potent antimicrobial and antioxidant activity along with the ability to stimulate apoptosis in A-549 cell line.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Nanopartículas Metálicas/administração & dosagem , Microalgas/química , Extratos Vegetais/farmacologia , Prata/química , Células A549 , Humanos , Técnicas In Vitro , Nanopartículas Metálicas/química , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química
10.
Mar Drugs ; 17(5)2019 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-31137657

RESUMO

Microalgae represent a potential source of renewable nutrition and there is growing interest in algae-based dietary supplements in the form of whole biomass, e.g., Chlorella and Arthrospira, or purified extracts containing omega-3 fatty acids and carotenoids. The commercial production of bioactive compounds from microalgae is currently challenged by the biorefinery process. This review focuses on the biochemical composition of microalgae, the complexities of mass cultivation, as well as potential therapeutic applications. The advantages of open and closed growth systems are discussed, including common problems encountered with large-scale growth systems. Several methods are used for the purification and isolation of bioactive compounds, and many products from microalgae have shown potential as antioxidants and treatments for hypertension, among other health conditions. However, there are many unknown algal metabolites and potential impurities that could cause harm, so more research is needed to characterize strains of interest, improve overall operation, and generate safe, functional products.


Assuntos
Microalgas/química , Valor Nutritivo , Compostos Fitoquímicos/química , Reatores Biológicos , Suplementos Nutricionais , Humanos , Microalgas/crescimento & desenvolvimento , Compostos Fitoquímicos/isolamento & purificação
11.
Mar Drugs ; 17(3)2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30889823

RESUMO

In recent years, the demand for naturally derived products has hiked with enormous pressure to propose or develop state-of-the-art strategies to meet sustainable circular economy challenges. Microalgae possess the flexibility to produce a variety of high-value products of industrial interests. From pigments such as phycobilins or lutein to phycotoxins and several polyunsaturated fatty acids (PUFAs), microalgae have the potential to become the primary producers for the pharmaceutical, food, and agronomical industries. Also, microalgae require minimal resources to grow due to their autotrophic nature or by consuming waste matter, while allowing for the extraction of several valuable side products such as hydrogen gas and biodiesel in a single process, following a biorefinery agenda. From a Mexican microalgae biodiversity perspective, more than 70 different local species have been characterized and isolated, whereas, only a minimal amount has been explored to produce commercially valuable products, thus ignoring their potential as a locally available resource. In this paper, we discuss the microalgae diversity present in Mexico with their current applications and potential, while expanding on their future applications in bioengineering along with other industrial sectors. In conclusion, the use of available microalgae to produce biochemically revenuable products currently represents an untapped potential that could lead to the solution of several problems through green technologies. As such, if the social, industrial and research communities collaborate to strive towards a greener economy by preserving the existing biodiversity and optimizing the use of the currently available resources, the enrichment of our society and the solution to several environmental problems could be attained.


Assuntos
Biodiversidade , Bioengenharia/métodos , Produtos Biológicos/química , Microalgas/química , Crescimento Sustentável , Biocombustíveis , Biomassa , México
12.
J Environ Sci Health B ; 54(5): 366-375, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30729858

RESUMO

The loss of yields from agricultural production due to the presence of pests has been treated over the years with synthetic pesticides, but the use of these substances negatively affects the environment and presents health risks for consumers and animals. The development of agroecological systems using biopesticides represents a safe alternative that contributes to the reduction of agrochemical use and sustainable agriculture. Microalgae are able to biosynthesize a number of metabolites with potential biopesticidal action and can be considered potential biological agents for the control of harmful organisms to soils and plants. The present work aims to provide a critical perspective on the consequences of using synthetic pesticides, offering as an alternative the biopesticides obtained from microalgal biomass, which can be used together with the implementation of environmentally friendly agricultural systems.


Assuntos
Agricultura/métodos , Agentes de Controle Biológico/farmacologia , Microalgas/química , Praguicidas/farmacologia , Animais , Humanos , Praguicidas/química , Medição de Risco , Desenvolvimento Sustentável
13.
Sci Total Environ ; 650(Pt 2): 2188-2198, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30292989

RESUMO

Estuarine environments are being constantly stressed by new sources of pollution (e.g. pesticides) derived from activities of industry and intensive agriculture. The present study aims at quantify pesticides of three different categories (fungicides, herbicides and insecticides) in the Louros River (Epirus region, North-Western Greece). A monitoring study of 34 compounds was carried out in surface river waters from June 2011 until May 2012. Seven water sampling stations were established and 35 water samples were collected. A solid-phase extraction (SPE) method coupled with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), depending on the compound, was developed and validated. During the monitoring study 25 pesticides were detected (13 herbicides, 9 insecticides, 3 fungicides). The most commonly encountered pesticides were quizalofop-ethyl, trifluralin and pendimethaline. Tebufenpyrad was found in all sampling stations and seasons, with the highest concentrations of 0.330 µg/L at Tsopeli Lagoon exceeding the rather low concentrations reported nationwide. Regarding the environmental risk due to the presence of target compounds in surface waters, this was estimated by calculating risk quotients (RQs) for different aquatic organisms (algae, zooplankton and fish). The results denoted a possible threat for the aquatic environment, rendering in this way the RQ method as a useful screening tool. In any case, further extensive study is needed for acetochlor, pirimiphos-methyl, endosulfan-a and azinphos-ethyl in order to better correlate their occurrence and potential toxic effects in aquatic life and humans.


Assuntos
Monitoramento Ambiental/métodos , Resíduos de Praguicidas/análise , Rios/química , Poluentes Químicos da Água/análise , Animais , Cromatografia Líquida/métodos , Peixes , Fungicidas Industriais/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Grécia , Herbicidas/análise , Inseticidas/análise , Espectrometria de Massas/métodos , Microalgas/química , Medição de Risco , Alga Marinha/química , Extração em Fase Sólida/métodos , Zooplâncton/química
14.
Molecules ; 23(11)2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30424551

RESUMO

Over the years, significant research efforts have been made to extract bioactive compounds by applying different methodologies for various applications. For instance, the use of bioactive compounds in several commercial sectors such as biomedical, pharmaceutical, cosmeceutical, nutraceutical and chemical industries, has promoted the need of the most suitable and standardized methods to extract these bioactive constituents in a sophisticated and cost-effective manner. In practice, several conventional extraction methods have numerous limitations, e.g., lower efficacy, high energy cost, low yield, etc., thus urges for new state-of-the-art extraction methodologies. Thus, the optimization along with the integration of efficient pretreatment strategies followed by traditional extraction and purification processes, have been the primary goal of current research and development studies. Among different sources, algal biome has been found as a promising and feasible source to extract a broader spectrum of bioactive compounds with point-of-care application potentialities. As evident from the literature, algal bio-products includes biofuels, lipids, polyunsaturated fatty acids, pigments, enzymes, polysaccharides, and proteins. The recovery of products from algal biomass is a matter of constant development and progress. This review covers recent advancements in the extraction methodologies such as enzyme-assisted extraction (EAE), supercritical-fluid extraction (SFE), microwave-assisted extraction (MAE) and pressurized-liquid extraction (PLF) along with their working mechanism for extracting bioactive compounds from algal-based sources to meet bio-economy challenges and opportunities. A particular focus has been given to design characteristics, performance evaluation, and point-of-care applications of different bioactive compounds of microalgae. The previous and recent studies on the anticancer, antibacterial, and antiviral potentialities of algal-based bioactive compounds have also been discussed with particular reference to the mechanism underlying the effects of these active constituents with the related pathways. Towards the end, the information is also given on the possible research gaps, future perspectives and concluding remarks.


Assuntos
Fracionamento Químico , Metaboloma , Metabolômica , Microalgas/química , Microalgas/metabolismo , Produtos Biológicos/química , Produtos Biológicos/metabolismo , Fracionamento Químico/métodos , Ecossistema , Metabolômica/métodos , Micro-Ondas , Sistemas Automatizados de Assistência Junto ao Leito , Pesquisa
15.
Environ Sci Pollut Res Int ; 25(32): 32721-32734, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30244443

RESUMO

Hydrochar prepared from the hydrothermal liquefaction of microalgae is characterized and investigated for copper removal from aqueous solution. Two hydrochars were prepared at 210 °C (HD210) and 250 °C (HD250). The effect of the initial solution pH, the initial Cu(II) concentration, the contact time, and the temperature will be investigated. According to the elemental analysis, the volatile matter in the hydrochars was lower and ash content was higher than those of microalgae. Also, pore characteristic analysis revealed that the surface area of the HD250 was higher than that of the HD210 suggesting a higher potential for the adsorption process. FTIR analysis and Boehm titration showed that both hydrochars contained oxygen-containing functional groups (OFG) on the surface which were effective for the copper removal. The adsorption experiments indicated that the amount of copper adsorbed reached a maximum value at the pH of 5 which was considered as the optimum solution pH. In addition, HD250 had a higher amount of copper adsorption than that of HD210 at all values of the solution pH. The adsorption data at the optimum solution pH was well fitted by the Langmuir's isotherm model and the adsorption process could be well described by the pseudo-2nd order kinetic model. Moreover, thermodynamic analysis revealed that copper adsorption onto the hydrochar was a physical endothermic process.


Assuntos
Cobre/química , Microalgas/química , Modelos Químicos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Soluções , Temperatura , Termodinâmica , Água/química
16.
Mar Drugs ; 16(9)2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30208611

RESUMO

The nutraceutical potential of microalgae boomed with the exploitation of new species and sustainable extraction systems of bioactive compounds. Thus, a laboratory-made continuous pressurized solvent extraction system (CPSE) was built to optimize the extraction of antioxidant compounds, such as carotenoids and PUFA, from a scarcely studied prokaryotic microalga, Gloeothece sp. Following "green chemical principles" and using a GRAS solvent (ethanol), biomass amount, solvent flow-rate/pressure, temperature and solvent volume-including solvent recirculation-were sequentially optimized, with the carotenoids and PUFA content and antioxidant capacity being the objective functions. Gloeothece sp. bioactive compounds were best extracted at 60 °C and 180 bar. Recirculation of solvent in several cycles (C) led to an 11-fold extraction increase of ß-carotene (3C) and 7.4-fold extraction of C18:2 n6 t (5C) when compared to operation in open systems. To fully validate results CPSE, this system was compared to a conventional extraction method, ultrasound assisted extraction (UAE). CPSE proved superior in extraction yield, increasing total carotenoids extraction up 3-fold and total PUFA extraction by ca. 1.5-fold, with particular extraction increase of 18:3 n3 by 9.6-fold. Thus, CPSE proved to be an efficient and greener extraction method to obtain bioactive extract from Gloeothece sp. for nutraceutical purposes-with low levels of resources spent, while lowering costs of production and environmental impacts.


Assuntos
Carotenoides/isolamento & purificação , Cianobactérias/química , Suplementos Nutricionais , Ácidos Graxos/isolamento & purificação , Química Verde/métodos , Microalgas/química , Antioxidantes/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Biomassa , Etanol/química , Química Verde/economia , Extração Líquido-Líquido/economia , Extração Líquido-Líquido/métodos , Temperatura , Ondas Ultrassônicas
17.
Spectrochim Acta A Mol Biomol Spectrosc ; 204: 287-294, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-29945111

RESUMO

The assessment for cell physiology and growth phases of microalgae plays important roles in ecological and environmental fields since it can be used to forecast water eutrophication level worldwidely. Herein, growth phases and environmental conditions of microalgae were assessed by combining resonance Raman mapping spectroscopy with multivariate analysis methods. And, primary Raman characteristic peaks of microalgae were mined with two-dimensional synchronous spectra. Thereafter, algal growth phases and environmental conditions of microalgae were preliminary classified with different tendencies of characteristic Raman peaks by unsupervised principal component analysis (PCA) and support vector machine (SVM) methods. Our results demonstrated that resonance Raman mapping spectroscopy with PCA and SVM classification models can be used to assess algal growth phases and preliminary predict environmental conditions with characteristic Raman spectra of microalgae in water bodies.


Assuntos
Eutrofização/fisiologia , Microalgas , Análise Espectral Raman/métodos , Células Cultivadas , Meios de Cultura , Microalgas/química , Microalgas/crescimento & desenvolvimento , Microalgas/fisiologia , Modelos Biológicos , Análise de Componente Principal , Máquina de Vetores de Suporte
18.
Int J Biol Macromol ; 116: 1296-1303, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29782981

RESUMO

Cationized starch-based flocculation processes are the subject of increasing attention because of their non-toxicity, biodegradability and relatively low price synthesized. The study aimed to evaluate the flocculability of different cationic starches using different concentrations of glycidyltrimethylammonium chloride (GTAC) with different degree of substitution (DS) ranged from 0.13 to 0.57. Cationized starch were characterized using Fourier Transform Infrared (FTIR), scanning electron microscopy (SEM) and toxicity checked using experimental animal procedure. They were used in comparison with aluminum sulphate for harvesting microalgal biomass collected from high rate algal pond (HRAP) at Zenin wastewater treatment plant (WWTP), Giza, Egypt. Jar test showed that gradual increase of aluminum sulphate doses (50-400 mg/L) has reduced algal suspension consequently turbidity with accompanied pH decrease from 8.6 to 6.6. Cationic starch with low DS has shown efficiency as flocculants by reducing turbidity of algal suspension from 110 to ≈2 NTU by gradual increase from 10 to 60 mg/L without change in pH value. Fecal coliforms and E. coli were inhibited from 9.6 × 102 and 8.4 × 10 CFU/ml to non-detectable count. Cationic starch with high DS (0.57) has the least effect of algae harvesting and turbidity reduction that 40 NTU after increase the dose to 60 mg/L. Results showed that 10 mg of cationic starch (DS = 0.13) has achieved the same flocculation efficiency of 100 mg of aluminum sulphate. In conclusion, further investigation is required to increase the degree of substitution of cationic starch, consequently the flocculation efficiency might be improved.


Assuntos
Escherichia coli/crescimento & desenvolvimento , Microalgas/química , Amido/química , Compostos de Alúmen/química , Animais , Compostos de Epóxi/química , Floculação , Camundongos , Microalgas/crescimento & desenvolvimento , Compostos de Amônio Quaternário/química
19.
Trends Biotechnol ; 36(2): 216-227, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29132753

RESUMO

Although microalgae are a promising biobased feedstock, industrial scale production is still far off. To enhance the economic viability of large-scale microalgae processes, all biomass components need to be valorized, requiring a multi-product biorefinery. However, this concept is still too expensive. Typically, downstream processing of industrial biotechnological bulk products accounts for 20-40% of the total production costs, while for a microalgae multi-product biorefinery the costs are substantially higher (50-60%). These costs are high due to the lack of appropriate and mild technologies to access the different product fractions such as proteins, carbohydrates, and lipids. To reduce the costs, simplified processes need to be developed for the main unit operations including harvesting, cell disruption, extraction, and possibly fractionation.


Assuntos
Biotecnologia/economia , Filtração/métodos , Extração Líquido-Líquido/métodos , Microalgas/química , Proteínas de Algas/isolamento & purificação , Biocombustíveis/economia , Biomassa , Biotecnologia/métodos , Carboidratos/isolamento & purificação , Filtração/economia , Floculação , Humanos , Líquidos Iônicos/química , Lipídeos/isolamento & purificação , Extração Líquido-Líquido/economia , Microalgas/crescimento & desenvolvimento , Microalgas/isolamento & purificação , Micro-Ondas , Sonicação/economia , Sonicação/métodos
20.
J Environ Manage ; 203(Pt 3): 988-998, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-28284810

RESUMO

Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts.


Assuntos
Dióxido de Carbono , Carbono/química , Chlorella/química , Microalgas/química , Centrais Elétricas/economia , Biomassa , Impostos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA