Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 66
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Food Chem ; 295: 101-109, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174738

RESUMO

Edible seaweeds are highly consumed food with a rich chlorophyll profile. Although seaweeds are mainly cooked ingested, the influence of cooking on the chlorophyll bioaccessibility remains unknown. In this research, cooked Nori, Sea Lettuce and Kombu were subjected to an in vitro digestion and following micellarization investigations. The processing of red seaweed does not affect the chlorophyll recovery, while cooking green and brown seaweeds implies an important increase in chlorophyll recovery after in vitro digestion. In this line, while cooking affects negatively the micellarization rate of chlorophyll derivatives in Nori and Kombu, it does not modify the micellarization in Sea Lettuce. Generally, the chlorophyll bioaccessibility of microwaved seaweeds is always higher than that of boiled ones. However, cooking improves the chlorophyll bioaccessibility in brown seaweeds, while decreases in red seaweeds. In conclusion, the characteristics of food matrix are the determinant factor on the chlorophyll bioaccessibility of cooked seaweeds.


Assuntos
Clorofila/análise , Culinária , Laminaria/química , Porphyra/química , Ulva/química , Disponibilidade Biológica , Cromatografia Líquida de Alta Pressão , Laminaria/metabolismo , Micro-Ondas , Porphyra/metabolismo , Espectrofotometria , Ulva/metabolismo , alfa-Amilases/metabolismo
2.
Int J Mol Sci ; 20(10)2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31096691

RESUMO

Blue light (BL) plays an important role in regulation of the growth and development of aquatic plants and land plants. Aureochrome (AUREO), the recent BL photoreceptor identified in photosynthetic stramenopile algae, is involved in the photomorphogenesis and early development of Saccharina japonica porophytes (kelp). However the factors that interact with the SjAUREO under BL conditions specifically are not clear. Here in our study, three high quality cDNA libraries with CFU over 5 × 106 and a recombination rate of 100% were constructed respectively through white light (WL), BL and darkness (DK) treatments to the juvenile sporophytes. Based on the constructed cDNA libraries, the interactors of SjAUREO were screened and analyzed. There are eighty-four genes encoding the sixteen predicted proteins from the BL cDNA library, sixty-eight genes encoding eighteen predicted proteins from the DK cDNA library, and seventy-four genes encoding nineteen proteins from the WL cDNA library. All the predicted proteins are presumed to interact with SjAUREO when co-expressed with SjAUREO seperately. The 40S ribosomal protein S6 (RPS6), which only exists in the BL treated cDNA library except for two other libraries, and which is essential for cell proliferation and is involved in cell cycle progression, was selected for detailed analysis. We showed that its transcription was up-regulated by BL, and was highly transcribed in the basal blade (meristem region) of juvenile sporophytes but less in the distal part. Taken together, our results indicated that RPS6 was highly involved in BL-mediated kelp cellular division and photomorphogenesis by interacting with SjAUREO.


Assuntos
Laminaria/metabolismo , Laminaria/efeitos da radiação , Luz , Proteína S6 Ribossômica/metabolismo , Proteína S6 Ribossômica/efeitos da radiação , Proteínas Ribossômicas/metabolismo , Proteínas Ribossômicas/efeitos da radiação , Proliferação de Células , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Biblioteca Gênica , Genes de Plantas/genética , Laminaria/genética , Células Fotorreceptoras/metabolismo , Células Fotorreceptoras/efeitos da radiação , Fotossíntese , Proteínas de Plantas/genética , Proteínas Ribossômicas/genética , Regulação para Cima/efeitos da radiação
3.
Bioresour Technol ; 281: 84-89, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30802819

RESUMO

Alginate oligosaccharides (AOS) showed various biological activities. Traditional protocol for producing AOS was a multiple-step and high-pollution procedure. In this study, a rapid and efficient AOS producing method was developed directly from Laminaria japonica. Natural sun-dried L. japonica with a feed ratio of 1:7 (w/v) was pretreated using cellulase with a dry weight of 3%, for releasing the fermentable sugars (8.5 g/L glucose and 15.2 g/L mannitol). Then, the engineered yeast Yarrowia lipolytica strain with alginate lyase activity was grown using an algae-based medium. After fermentation for 72 h, glucose and mannitol were completely consumed, and 71.8 mM AOS was extracted from the fermentation supernatant. The degree of polymerization (DP) was ranging from 2 to 3. The recovery yield of AOS was about 91.7%. The purity of the extracted AOS was 92.6%. Overall, our work provided new insights for the development of green biotechnologies for oligosaccharide production from seaweed.


Assuntos
Fermentação , Laminaria/metabolismo , Oligossacarídeos/metabolismo , Alginatos/metabolismo , Hidrólise , Alga Marinha/metabolismo , Yarrowia/genética , Yarrowia/metabolismo
4.
Bioresour Technol ; 276: 361-368, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30658265

RESUMO

This work investigated the thermophilic (55 °C) co-digestion performance both in batch and continuous mode operation. The biochemical methane potentials of L. digitata and cattle manure were 308 ±â€¯24 and 203 ±â€¯33 mL CH4/g VS, respectively. The optimum co-digestion feedstock ratio was found to be 80% macroalgae: 20% manure on a volatile solids basis, which produced 290 ±â€¯19 mL CH4/g VS under long-term and stable continuous operation at an organic loading rate of 2 g VS/L/d and hydraulic retention time of 15 days. Simulations of the batch and continuous experiments were, for the first time, carried out using an integrated anaerobic bioconversion model without structural modifications. Close fits between measured and simulated data provided mutual confirmation of experimental reliability and model robustness, and provided new perspectives for the use of the software tool.


Assuntos
Laminaria/metabolismo , Esterco , Animais , Reatores Biológicos , Bovinos , Metano/biossíntese , Reprodutibilidade dos Testes
5.
J Sci Food Agric ; 98(10): 3644-3650, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29250785

RESUMO

BACKGROUND: Phlorotannins (PhTs) are marine tannins consisting of phloroglucinol subunits connected via carbon-carbon and ether linkages. These have non-covalent protein binding properties and are, therefore, expected to be beneficial in protecting protein from hydrolysis during ruminal fermentation. In this study, the effectiveness of a methanolic PhTs extract from Laminaria digitata (10, 20, 40, 50, 75 and 100 g kg-1 tannin-free grass silage, with or without addition of polyethylene glycol (PEG), was investigated in vitro on protection of dietary protein and reduction of methane (CH4 ) in ruminal fluid. RESULTS: Addition of PhTs had linear (P < 0.0001) and quadratic (P = 0.0003) effects on gas and CH4 production, respectively. Optimal dosage of PhTs was 40 g kg-1 as at this point CH4 decreased (P < 0.0001) from 24.5 to 15.2 mL g-1 organic matter (OM), without affecting gas production (P = 0.3115) and total volatile fatty acids (P = 1.000). Ammonia trended (P = 0.0903) to decrease from 0.49 to 0.39 mmol g-1 OM, indicating protection of protein. Addition of PEG inhibited the effect of tannins at all dosage levels, and none of the fermentation parameters differed from the control. CONCLUSION: PhTs effectively protected protein from fermentation and reduced ruminal methanogenesis. © 2017 Society of Chemical Industry.


Assuntos
Laminaria/metabolismo , Metano/metabolismo , Proteínas de Plantas/metabolismo , Rúmen/metabolismo , Taninos/química , Amônia/metabolismo , Ração Animal/análise , Animais , Bovinos , Digestão , Ácidos Graxos Voláteis/metabolismo , Fermentação , Laminaria/química , Proteólise , Silagem/análise
6.
J Agric Food Chem ; 65(44): 9595-9602, 2017 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-29058916

RESUMO

Marine phlorotannins (PhT) from Laminaria digitata might protect feed proteins from ruminal digestion by formation of insoluble non-covalent tannin-protein complexes at rumen pH (6-7). Formation and disintegration of PhT-protein complexes was studied with ß-casein (random coil) and bovine serum albumin (BSA, globular) at various pH. PhT had similar binding affinity for ß-casein and BSA as pentagalloyl glucose, as studied by fluorescence quenching. The affinity of PhT for both proteins was independent of pH (3.0, 6.0, and 8.0). In the presence of PhT, the pH range for precipitation of tannin-protein complexes widened to 0.5-1.5 pH units around the isoelectric point (pI) of the protein. Complete protein resolubilization from insoluble PhT-protein complexes was achieved at pH 7 and 2 for ß-casein and BSA, respectively. It was demonstrated that PhT modulate the solubility of proteins at neutral pH and that resolubilization of PhT-protein complexes at pH deviating from pI is mainly governed by the charge state of the protein.


Assuntos
Caseínas/química , Laminaria/química , Extratos Vegetais/química , Rúmen/metabolismo , Alga Marinha/química , Soroalbumina Bovina/química , Taninos/química , Animais , Caseínas/metabolismo , Bovinos , Concentração de Íons de Hidrogênio , Ponto Isoelétrico , Laminaria/metabolismo , Extratos Vegetais/metabolismo , Rúmen/química , Alga Marinha/metabolismo , Soroalbumina Bovina/metabolismo , Solubilidade , Taninos/metabolismo
7.
Cryobiology ; 79: 50-55, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28941986

RESUMO

In this study, water-soluble Laminaria japonica polysaccharide3 (LJP-P3) was investigated for the cryoprotective effects on bull sperm. Five concentrations of LJP-P3 with 0.1, 1, 10, 50 and 100 mmol/L were added into the extenders of bull semen, respectively, and the effects on quality of sperm after freezing-thawing were assessed. The results showed that the kinematic parameters of bull sperm including linear motile sperm (LM), curvilinear line velocity (VCL) value, straight line velocity (VSL) and velocity of the average path (VAP) were greater in the extenders containing LJP-P3 (P<0.05). In comparison to those of other treatments and control group the extenders containing 1.0, 10.0 and 50.0 mmol/L of LJP-P3 led to higher percentage of mitochondrial activity and sperm membrane integrity(P<0.05), and the acrosome integrity of bull cryopreservation sperm were significantly improved in all treatment groups. Moreover, the higher GSH-Px, SOD and CAT levels in bull cryopreservation sperm were favored from the extenders of 10.0, 50.0 and 100.0 mmol/L LJP-P3 added (P<0.05) compared with other treatments and control group. In addition, the results of artificial insemination showed that both the pregnancy rate and the number of calving were higher in the group of semen containing 10 mmol/L of LJP-P3 than that of control group (P <0.05). In summary, LJP-P3 exhibited a greater cryoprotective effect to bull sperm and the most suitable concentration of LJP-P3 is 10.0 mmol/L.


Assuntos
Antioxidantes/farmacologia , Criopreservação/métodos , Crioprotetores/farmacologia , Polissacarídeos/farmacologia , Preservação do Sêmen/métodos , Motilidade Espermática/efeitos dos fármacos , Acrossomo/efeitos dos fármacos , Animais , Catalase/metabolismo , Bovinos , Feminino , Congelamento , Glutationa Peroxidase/metabolismo , Inseminação Artificial , Laminaria/metabolismo , Masculino , Mitocôndrias/efeitos dos fármacos , Gravidez , Sêmen/efeitos dos fármacos , Análise do Sêmen , Espermatozoides/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Água/metabolismo
8.
PLoS One ; 12(7): e0180760, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28704453

RESUMO

Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea). To test this hypothesis we examined stable nitrogen isotope ratios (δ15N) of 100- to 135-year-old Saccharina specimens preserved at the Herbarium (Hokkaido University Museum). δ15N values of the paleo-Saccharina specimens collected from this region were in the range of 10‰, which is significantly higher than the current 3-7‰ in freshly sampled Saccharina spp. This high δ15N indicates that spawning herring (Clupea pallasii) had potentially been a significant source of dissolved inorganic nitrogen (DIN) absorbed by Saccharina, acting as an organism forming a vector for transporting nutrients from eutrophic to oligotrophic coastal ecosystems. Our findings support the hypothesis of so-called "herring-derived nutrients."


Assuntos
Laminaria/química , Isótopos de Nitrogênio/análise , Animais , Peixes/metabolismo , Cadeia Alimentar , Laminaria/metabolismo , Água do Mar/química
9.
Food Chem Toxicol ; 104: 95-108, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28161465

RESUMO

The presence of contaminants in aquatic ecosystems can cause serious problems to the environment and marine organisms. This study aims to evaluate the phycoremediation capacity of macroalgae Laminaria digitata for pesticides (diflubenzuron and lindane) and toxic elements (cadmium and copper) in seawater in the presence or absence of mussels. The photosynthetic activity was monitored in the macroalgae to assess its "physiological status". The results showed that the presence of algae decreased diflubenzuron concentration in mussels by 70% after 120 h of exposure. Additionally, this macroalgae was efficient to reduce lindane, Cu and Cd in seawater; even though it not was able to reduce these contaminants in mussels. The studied pollutants did not affect the physiological status of macroalgae. This study reveals that the application of phycoremediation with macroalgae can be an useful and effective mitigation strategy to remove/decrease contaminant levels from the aquatic environment.


Assuntos
Cádmio/metabolismo , Cobre/metabolismo , Diflubenzuron/metabolismo , Recuperação e Remediação Ambiental/métodos , Hexaclorocicloexano/metabolismo , Laminaria/metabolismo , Alga Marinha/metabolismo , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Cádmio/análise , Cobre/análise , Diflubenzuron/análise , Poluentes Químicos da Água/análise
10.
Bioresour Technol ; 218: 224-31, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27371795

RESUMO

Aquatic micro-algae can be used as feedstocks for gaseous biofuel production via biological fermentation. However, micro-algae usually have low C/N ratios, which are not advantageous for fermentation. In this study, carbon-rich macro-algae (Laminaria digitata) mixed with nitrogen-rich micro-algae (Chlorella pyrenoidosa and Nannochloropsis oceanica) were used to maintain a suitable C/N ratio of 20 for a two-stage process combining hydrogen and methane fermentation. Co-fermentation of L. digitata and micro-algae facilitated hydrolysis and acidogenesis, resulting in hydrogen yields of 94.5-97.0mL/gVS; these values were 15.5-18.5% higher than mono-fermentation using L. digitata. Through the second stage of methane co-fermentation, a large portion of energy remaining in the hydrogenogenic effluents was recovered in the form of biomethane. The two-stage batch co-fermentation markedly increased the energy conversion efficiencies (ECEs) from 4.6-6.6% during the hydrogen fermentation to 57.0-70.9% in the combined hydrogen and methane production.


Assuntos
Biocombustíveis , Reatores Biológicos , Hidrogênio/metabolismo , Metano/metabolismo , Microalgas/metabolismo , Biomassa , Carbono/análise , Carbono/química , Carbono/metabolismo , Chlorella/microbiologia , Conservação de Recursos Energéticos , Fermentação , Hidrogênio/análise , Hidrogênio/química , Laminaria/metabolismo , Metano/análise , Metano/química , Nitrogênio/análise , Nitrogênio/química , Nitrogênio/metabolismo , Energia Renovável
11.
Bioresour Technol ; 211: 108-16, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27010340

RESUMO

In this work, granular biochar, Laminaria japonica-derived biochar (LB)-calcium alginate beads (LB-CAB), was successfully prepared by dropping a mixture of powder biochar and alginate solution into a calcium chloride solution for phosphate adsorption. Among different marine macroalgae derived biochars, LB exhibited the best performance, showing a phosphate removal rate of 97.02%, which was attributed to its high Ca/P and Mg/P ratios. With increasing pyrolysis temperature up to 600°C, the physicochemical properties of LB became suitable for adsorbing phosphate. Experimental results of kinetics and equilibrium isotherms at different temperatures (10-30°C) showed that the phosphate adsorption process is endothermic and is mainly controlled by external mass transfer and the intraparticle diffusion rate. The maximum adsorption capacity was found to be 157.7mgg(-1) at 30°C, as fitted by the Langmuir-Freundlich model, which is higher than capacities of other powder form of biochars.


Assuntos
Alginatos/química , Cálcio/química , Carvão Vegetal/análise , Fosfatos/isolamento & purificação , Alga Marinha/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Carvão Vegetal/metabolismo , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Cinética , Laminaria/metabolismo , Microesferas , Fosfatos/farmacocinética , Poluentes Químicos da Água/farmacocinética
12.
Bioresour Technol ; 209: 213-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26970924

RESUMO

Biomethane produced from seaweed may be used as a transport biofuel. Seasonal variation will have an effect on this industry. Laminaria digitata, a typical Irish brown seaweed species, shows significant seasonal variation both in proximate, ultimate and biochemical composition. The characteristics in August were optimal with the lowest level of ash (20% of volatile solids), a C:N ratio of 32 and the highest specific methane yield measured at 327LCH4kgVS(-1), which was 72% of theoretical yield. The highest yield per mass collected of 53m(3)CH4t(-1) was achieved in August, which is 4.5 times higher than the lowest value, obtained in December. A seaweed cultivation area of 11,800ha would be required to satisfy the 2020 target for advanced biofuels in Ireland, of 1.25% renewable energy supply in transport (RES-T) based on the optimal gross energy yield obtained in August (200GJha(-1)yr(-1)).


Assuntos
Biocombustíveis , Laminaria/metabolismo , Metano/biossíntese , Estações do Ano , Alga Marinha/metabolismo , Carbono/análise , Carbono/metabolismo , Conservação de Recursos Energéticos , Irlanda , Laminaria/química , Nitrogênio/análise , Nitrogênio/metabolismo , Alga Marinha/química
13.
Appl Environ Microbiol ; 82(10): 2975-2987, 2016 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-26969704

RESUMO

The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22(T) can completely degrade alginate. This work reveals that strain HZ22(T) has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22(T) are worth further research.


Assuntos
Flavobacteriaceae/classificação , Flavobacteriaceae/isolamento & purificação , Genoma Bacteriano , Laminaria/metabolismo , Laminaria/microbiologia , Polissacarídeos/metabolismo , Análise de Sequência de DNA , Técnicas de Tipagem Bacteriana , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Flavobacteriaceae/genética , Flavobacteriaceae/metabolismo , Loci Gênicos , Genótipo , Redes e Vias Metabólicas/genética , Filogenia , RNA Ribossômico 16S/genética
14.
Bioresour Technol ; 205: 118-25, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26820925

RESUMO

Algae may be fermented to produce hydrogen. However micro-algae (such as Arthrospira platensis) are rich in proteins and have a low carbon/nitrogen (C/N) ratio, which is not ideal for hydrogen fermentation. Co-fermentation with macro-algae (such as Laminaria digitata), which are rich in carbohydrates with a high (C/N) ratio, improves the performance of hydrogen production. Algal biomass, pre-treated with 2.5% dilute H2SO4 at 135°C for 15min, effected a total yield of carbohydrate monomers (CMs) of 0.268g/g volatile solids (VS). The CMs were dominating by glucose and mannitol and most (ca. 95%) were consumed by anaerobic fermentative micro-organisms during subsequent fermentation. An optimal specific hydrogen yield (SHY) of 85.0mL/g VS was obtained at an algal C/N ratio of 26.2 and an algal concentration of 20g VS/L. The overall energy conversion efficiency increased from 31.3% to 54.5% with decreasing algal concentration from 40 to 5 VS g/L.


Assuntos
Cianobactérias/metabolismo , Etanol/metabolismo , Ácidos Graxos Voláteis/biossíntese , Hidrogênio/metabolismo , Laminaria/metabolismo , Biocombustíveis , Biomassa , Carboidratos/química , Carbono/metabolismo , Ácidos Graxos Voláteis/metabolismo , Fermentação , Glucose/metabolismo , Manitol/metabolismo , Microalgas/metabolismo , Nitrogênio/metabolismo , Alga Marinha/metabolismo
15.
Mar Drugs ; 13(9): 5947-75, 2015 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-26393620

RESUMO

The cultivation of macroalgae to supply the biofuel, pharmaceutical or food industries generates a considerable amount of organic residue, which represents a potential substrate for biomethanation. Its use optimizes the total resource exploitation by the simultaneous disposal of waste biomaterials. In this study, we explored the biochemical methane potential (BMP) and biomethane recovery of industrial Laminaria japonica waste (LJW) in batch, continuous laboratory and pilot-scale trials. Thermo-acidic pretreatment with industry-grade HCl or industrial flue gas condensate (FGC), as well as a co-digestion approach with maize silage (MS) did not improve the biomethane recovery. BMPs between 172 mL and 214 mL g(-1) volatile solids (VS) were recorded. We proved the feasibility of long-term continuous anaerobic digestion with LJW as sole feedstock showing a steady biomethane production rate of 173 mL g(-1) VS. The quality of fermentation residue was sufficient to serve as biofertilizer, with enriched amounts of potassium, sulfur and iron. We further demonstrated the upscaling feasibility of the process in a pilot-scale system where a CH4 recovery of 189 L kg(-1) VS was achieved and a biogas composition of 55% CH4 and 38% CO2 was recorded.


Assuntos
Reatores Biológicos , Laminaria/metabolismo , Eliminação de Resíduos/métodos , Anaerobiose , Fermentação , Resíduos Industriais , Cinética , Metano/química , Metano/metabolismo , Projetos Piloto
16.
Bioresour Technol ; 197: 310-7, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26342344

RESUMO

A wild-growing glucose-rich (i.e. 56.7% glucose content) brown seaweed species Laminaria digitata, collected from the North Coast of Denmark in August 2012, was used as the feedstock for an integrated bioethanol and protein production. Glutamic acid and aspartic acid are the two most abundant amino acids in the algal protein, both with proportional content of 10% in crude protein. Only minor pretreatment of milling was used on the biomass to facilitate the subsequent enzymatic hydrolysis and fermentation. The Separate Hydrolysis and Fermentation (SHF) resulted in obviously higher ethanol yield than the Simultaneous Saccharification and Fermentation (SSF). High conversion rate at maximum of 84.1% glucose recovery by enzymatic hydrolysis and overall ethanol yield at maximum of 77.7% theoretical were achieved. Protein content in the solid residues after fermentation was enriched by 2.7 fold, with similar distributions of amino acids, due to the hydrolysis of polymers in the seaweed cell wall matrix.


Assuntos
Proteínas de Algas/metabolismo , Etanol/metabolismo , Laminaria/química , Biomassa , Dinamarca , Fermentação , Glucose/metabolismo , Hidrólise , Laminaria/metabolismo , Alga Marinha/química , Alga Marinha/metabolismo
17.
Mar Drugs ; 13(7): 4357-74, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26184241

RESUMO

This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a reference site in Denmark (2013-2014). Generally, there was no difference in the biomass composition between sites; however, significant seasonal changes were found. The lipid concentration varied from 0.62%-0.88% dry weight (DW) in July to 3.33%-3.35% DW in November (p < 0.05) in both sites. The fatty acid composition in January was significantly different from all the other sampling months. The dissimilarities were mainly explained by changes in the relative abundance of 20:5n-3 (13.12%-33.35%), 14:0 (11.07%-29.37%) and 18:1n-9 (10.15%-16.94%). Polyunsaturated fatty acids (PUFA's) made up more than half of the fatty acids with a maximum in July (52.3%-54.0% fatty acid methyl esters; FAME). This including the most appreciated health beneficial PUFA's, eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), but also arachidonic (ARA) and stearidonic acid (SDA), which are not found in land vegetables such as cabbage and lettuce. Compared to fat (salmon) and lean fish (cod) this seaweed species contains higher proportions of ARA and SDA, but lower EPA (only cod) and DHA. Conclusively, the season of harvest is important for the choice of lipid quantity and quality, but the marine vegetables provide better sources of EPA, DHA and long-chain (LC)-PUFA's in general compared to traditional vegetables.


Assuntos
Ácidos Graxos/análise , Laminaria/química , Lipídeos/análise , Alga Marinha/química , Aquicultura/métodos , Ácidos Docosa-Hexaenoicos/análise , Ácido Eicosapentaenoico/análise , Ácidos Graxos Insaturados/análise , Laminaria/metabolismo , Ácido Linoleico/análise , Alga Marinha/metabolismo
18.
Bioresour Technol ; 169: 455-461, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25084043

RESUMO

As aquatic biomass which is called "the third generation biomass", Laminaria japonica (also known as Saccharina japonica) consists of mannitol and alginate which are the main polysaccharides of algal carbohydrates. In this study, oleaginous yeast (Cryptococcus curvatus) was used to produce lipid from carbon sources derived from Laminaria japonica. Volatile fatty acids (VFAs) were produced by fermentation of alginate extracted from L. japonica. Thereafter, mannitol was mixed with VFAs to culture the oleaginous yeast. The highest lipid content was 48.30%. The composition of the fatty acids was similar to vegetable oils. This is the first confirmation of the feasibility of using macroalgae as a carbon source for biodiesel production.


Assuntos
Biocombustíveis , Biotecnologia/métodos , Carbono/farmacologia , Laminaria/metabolismo , Alga Marinha/metabolismo , Alginatos/metabolismo , Técnicas de Cultura Celular por Lotes , Biomassa , Cryptococcus/crescimento & desenvolvimento , Cryptococcus/metabolismo , Ésteres/metabolismo , Ácidos Graxos Voláteis/biossíntese , Fermentação/efeitos dos fármacos , Laminaria/efeitos dos fármacos , Alga Marinha/efeitos dos fármacos , Undaria/efeitos dos fármacos , Undaria/metabolismo
19.
Bioresour Technol ; 169: 573-580, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25103034

RESUMO

The potential of supercritical water gasification (SCWG) of macroalgae for hydrogen and methane production has been investigated in view of the growing interest in a future macroalgae biorefinery concept. The compositions of syngas from the catalytic SCWG of Laminaria hyperborea under varying parameters including catalyst loading, feed concentration, hold time and temperature have been investigated. Their effects on gas yields, gasification efficiency and energy recovery are presented. Results show that the carbon gasification efficiencies increased with reaction temperature, reaction hold time and catalyst loading but decreased with increasing feed concentrations. In addition, the selectivity towards hydrogen and/or methane production from the SCWG tests could be controlled by the combination of catalysts and varying reaction conditions. For instance, Ru/Al2O3 gave highest carbon conversion and highest methane yield of up to 11 mol/kg, whilst NaOH produced highest hydrogen yield of nearly 30 mol/kg under certain gasification conditions.


Assuntos
Biotecnologia/métodos , Carboidratos/química , Gases/química , Laminaria/metabolismo , Alga Marinha/metabolismo , Água/química , Reatores Biológicos , Catálise , Temperatura Alta , Fatores de Tempo
20.
Water Sci Technol ; 70(1): 136-43, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25026591

RESUMO

The uranium(VI) adsorption efficiency of non-living biomass of brown algae was evaluated in various adsorption experimental conditions. Several different sizes of biomass were prepared using pretreatment and surface-modification steps. The kinetics of uranium uptake were mainly dependent on the particle size of the prepared Laminaria japonica biosorbent. The optimal particle size, contact time, and injection amount for the stable operation of the wastewater treatment process were determined. Spectroscopic analyses showed that uranium was adsorbed in the porous inside structure of the biosorbent. The ionic diffusivity in the biomass was the dominant rate-limiting factor; therefore, the adsorption rate was significantly increased with decrease of particle size. From the results of comparative experiments using the biosorbents and other chemical adsorbents/precipitants, such as activated carbons, zeolites, and limes, it was demonstrated that the brown algae biosorbent could replace the conventional chemicals for uranium removal. As a post-treatment for the final solid waste reduction, the ignition treatment could significantly reduce the weight of waste biosorbents. In conclusion, the brown algae biosorbent is shown to be a favorable adsorbent for uranium(VI) removal from radioactive wastewater.


Assuntos
Biomassa , Laminaria/metabolismo , Urânio/isolamento & purificação , Poluentes Radioativos da Água/isolamento & purificação , Adsorção , Biodegradação Ambiental , Carbono/química , Difusão , Íons , Cinética , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Resíduos Radioativos , Eliminação de Resíduos/métodos , Soluções , Propriedades de Superfície , Temperatura Ambiente , Fatores de Tempo , Purificação da Água/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA