Brown Seaweed Laminaria Digitata Research Articles

The impact of dietary Laminaria digitata and alginate lyase supplementation on the weaned piglet liver: A comprehensive proteomics and metabolomics approach

The brown seaweed Laminaria digitata, a novel feedstuff for weaned piglets, has potentially beneficial prebiotic properties. However, its recalcitrant cell wall challenges digestion in monogastrics. Alginate lyase is a promising supplement to mitigate this issue. This study's aim was to investigate the impact of incorporating 10% dietary Laminaria digitata, supplemented with alginate lyase, on the hepatic proteome and metabolome of weaned piglets. These diets introduced minor variations to the metabolome and caused significant shifts in the proteome. Dietary seaweed provided a rich source of n-3 PUFAs that could signal hepatic fatty acid oxidation (FABP, ACADSB and ALDH1B1). This may have affected the oxidative stability of the tissue, requiring an elevated abundance of GST for regulation. The presence of reactive oxygen species likely inflicted protein damage, triggering increased proteolytic activity (LAPTM4B and PSMD4). Alginate lyase supplementation augmented the number of differentially abundant proteins, which included GBE1 and LDHC, contributing to maintain circulating glucose levels by mobilizing glycogen stores and branched-chain amino acids. The enzymatic supplementation with alginate lyase amplified the effects of the seaweed-only diet. An additional filter was employed to test the effect of missing values on the proteomics analysis, which is discussed from a technical perspective. SignificanceBrown seaweeds such as Laminaria digitata have prebiotic and immune-modulatory components, such as laminarin, that can improve weaned piglet health. However, they have recalcitrant cell wall polysaccharides, such as alginate, that can elicit antinutritional effects on the monogastric digestive system. The aim of this study was to evaluate the effect of a high level of dietary L. digitata and alginate lyase supplementation on the hepatic metabolism of weaned piglets, using high throughput Omics approaches.

Characterisation of laminarin extracted from brown seaweed Laminaria digitata, using optimized ultrasound- and ultrafiltration-assisted extraction method

The present study reported the extraction and characterisation of laminarin from Laminaria digitata. Hydrochloric acid concentration and extraction time were investigated by central composite design for optimizing extraction conditions. Regarding purification of the supernatant after the extraction process, membrane ultrafiltration was selected over pH shifting, ethanol precipitation and freeze-drying. With the assistance of ultrasound technology in the extraction process, the highest laminarin extraction yield and purity were obtained up to 57.34 ± 1.58 % and 81.10 ± 0.37 %, respectively. The molecular weight of laminarin extracts is in the range of 5.61 to 5.95 kDa. The Fourier-transform infrared spectroscopy (FT-IR) spectral features of the averaged spectra were depicted as absorbance peaks at the wavelengths of 3340 cm−1 and 2922 cm−1, which were related to OH and CH stretching of laminarin. US probe extract showed the highest scavenging capacity of 52.96 % while the HCl conventional extract exhibited the lowest scavenging capacity of 30.82 %. All the optimized laminarin extracts showed higher cytotoxicity in A549, A431, and Caco-2 carcinomas, effectively inducing cancer cell death in a time- and dose-dependent manner, and lower cytotoxicity in BEAS-2B normal human bronchial epithelial cells when compared to commercial laminarin.

Angiotensin-I-Converting Enzyme Inhibitory Activity of Protein Hydrolysates Generated from the Macroalga Laminaria digitata (Hudson) JV Lamouroux 1813.

Seaweeds have a long history of use as both food and medicine, especially in Asian cultures. Moreover, there is growing interest in the use of seaweed ingredients and bioactive compounds in pharmaceutical and nutraceutical products. One ailment that seaweed bioactive compounds may impact is hypertension caused by the enzyme Angiotensin Converting Enzyme 1 (ACE-1; EC 3.4.15.1), found within the Renin-Angiotensin Aldosterone System (RAAS), which causes vasoconstriction of blood vessels, including veins and arteries. The aim of this paper is to generate bioactive peptide containing protein hydrolysates from the brown seaweed Laminaria digitata (Hudson) JV Lamouroux 1813. Proteins were extracted from this seaweed by disrupting the seaweed cell wall using a combination of carbohydrases and proteolytic enzymes. Bioactive peptide containing permeates were generated from L. digitata protein hydrolysates, and both hydrolysates and permeates were screened for their ability to inhibit the enzyme ACE-1. The protein content of the permeate fractions was found to be 23.87% compared to the untreated seaweed, which contained 15.08% protein using LECO analysis. Hydrolysis and filtration resulted in a “white” protein powder, and the protein content of this powder increased by 9% compared to the whole seaweed. The total amino acid (TAA) content of the L. digitata protein permeate was 53.65 g/100 g of the sample, and contains over 32% essential amino acids (EAA). Furthermore, the L. digitata permeate was found to inhibit the ACE-1 enzyme by 75% when compared to the commercial drug Captopril© when assayed at a concentration of 1 mg/mL. The inhibition of ACE-1 (the IC50 value) of 590 µg/mL for the L. digitata permeate compares well with Captopril©, which had 100% inhibition of ACE-1, with an IC50 value of 500 µg/mL. This study indicates that there is potential to develop protein powders with ACE-1 inhibitory bioactivities from the brown seaweed L. digitata using enzymatic hydrolysis as a cell disruption and protein extraction/hydrolysate generation procedure.

Antioxidant and Antiaging Properties of Agar Obtained from Brown Seaweed Laminaria digitata (Hudson) in D-Galactose-Induced Swiss Albino Mice.

The present paper explores the antioxidant and antiaging properties of agar extracted from Laminaria digitata (L. digitata) on a D-galactose (D-Gal)-induced mouse model. Experimental mice were divided into four groups: group I comprised of control nontreated mice, group II comprised of D-Gal-induced mice, group III mice were treated with extracted agar after D-Gal induction, and group IV mice were given ascorbic acid as a positive control. Antioxidant enzymes and aging marker proteins declined significantly in group II, whereas they were normal in group III and group IV mice. Expressions of interleukin-1β (IL-1β) in D-Gal-induced mice were significantly enhanced in the liver and brain of the experimental mice, which were otherwise normal in agar-treated mice. Also, IL-6 levels were significantly increased in the liver and reversed in the brain of D-gal mice, while it was regularly in the agar-treated mice. The histopathological analysis of D-Gal-induced mice showed spongiosis and tangles in brain cells, increased fat and decreased collagen contents in the skin, and few dilated sinuses in the hepatic cells. The changes were under control in group III and group IV mice, suggesting the protective effects of agar extracted from L. digitata and ascorbic acid.

Improvement in biohydrogen and volatile fatty acid production from seaweed through addition of conductive carbon materials depends on the properties of the conductive materials

Fermentative production of biohydrogen and volatile fatty acids (VFAs) from advanced feedstocks such as seaweed provides opportunities in the carbon-neutral bioeconomy. The gap in the state of the art exists in overcoming both the low fermentation efficiency associated with the rigid structure of seaweed and the inefficient metabolic electron transfer within the microbial communities. This study evaluated the effects of carbonaceous additives (such as graphene and various biochars) on biohydrogen fermentation of glucose, cellulose, and the brown seaweed Laminaria digitata. The impacts of carbonaceous additives varied significantly in terms of hydrogen production, VFA profiles, and microbial communities. Graphene and wood-derived biochar (Wood_Biochar) were shown to be superior to draff-derived biochars. In the fermentation of L. digitata, graphene and Wood_Biochar significantly reduced the lag-phase time by 47% and 49%, respectively. Microbial analysis revealed that the enhanced fermentation was ascribed to the enrichment of Thermoanaerobacterium genus in response to carbonaceous additives. Kinetic correlations between the fermentation parameters and the properties of the additives suggested that the graphitic structure and electrical conductivity might play a crucial role in facilitating the fermentation. The mechanisms might be ascribed to (1) the supported biofilm growth and (2) enhancement in microbial electron transfer induced by the additives.

Antiskin Cancer and Antioxidant Activities of Formulated Agar from Brown Seaweed Laminaria digitata (Hudson) in Dimethyl Benzanthracene-Induced Swiss Albino Mice

This study explores the antiskin cancer effect of formulated agar (FA) from Laminaria digitata on dimethyl benzanthracene- (DMBA-) induced skin cancer mice. The agar was extracted and formulated (emulgel), and FA was biochemically characterized. The in vitro cytotoxicity of FA was tested using NTT 3T3 mice fibroblast cells. The mice were divided into 5 groups: group 1 served as control mice, group 2 mice were considered as DMBA-induced cancer control, group 3 mice were FA pretreated (low dose) + DMBA-induced mice, group 4 mice were FA pretreated (high dose) + DMBA-induced mice, and group 5 were positive control + DMBA-induced mice. The behaviour and biochemical markers of cancer were significantly decreased in group 2 (DMBA-induced) mice, which were brought to near normalcy by FA pretreated mice (groups 3 and 4). The levels of p53 and keratin were significantly elevated in group 2 mice and these levels were decreased in 3 and 4 mice as well. The histopathological examination of DMBA-induced mice was shown degenerated cervical patches in the skin, cirrhosis in liver, oedema in the renal tissue, and swollen and damage in cardiac tissue, which were reduced for the mice applied with FA. This confirms that FA pretreatment offered potential antiskin cancer property.

Composition analysis and minimal treatments to solubilize polysaccharides from the brown seaweed Laminaria digitata for microbial growth of thermophiles

Brown macroalgae (Phaeophyta) hold high potential as feedstock for biorefineries due to high biomass productivity and carbohydrate content. They are, however, a challenging, unconventional feedstock for microbial refining and several processing problems need to be solved to make them a viable option. Pre-treatment is necessary to enhance accessibility and solubility of the biomass components but should be minimal and mild to assure sustainable and cost-effective processing. Here, two routes to pre-treatLaminaria digitata to release polysaccharides were investigated: hot water pre-treatment by autoclaving (121 °C, 20 min or 60 min) and a two-step extraction with mild acid (0.1 M HCl) followed by alkaline treatment. Hot water pre-treatment resulted in partial extraction of a mixture of polysaccharides consisting of alginate, fucoidan and laminarin. After mild acid pre-treatment, alginate was found in the remaining insoluble residues and was extracted in a second step via alkaline treatment using Na2CO3 (0.15 M) at 80 °C and CaCl2 (10%) for the precipitation. In addition to carbohydrates, a fraction of other components such as proteins, phenolic compounds, minerals and trace elements was detected in the extracts. Cultivation of the thermophilic bacterial strains Rhodothermus marinus DSM 16675 and Bacillus methanolicus MGA3 (ATCC 53907) in media supplemented with the respective extracts resulted in growth of both strains, indicating that they were able to utilize the available carbon source for growth. R. marinus displayed the highest cell density in the medium containing the extract from acid pre-treatment, whereas B. methanolicus growth was highest with the extract from hot water pre-treatment.

Comparison of pre-treatments to reduce salinity and enhance biomethane yields of Laminaria digitata harvested in different seasons

Pre-treatment can enhance anaerobic digestion of seaweed; however, seasonal variation in the biochemical composition of seaweed has a significant impact on the pre-treatment effect. In this study, various pre-treatments were employed for the brown seaweed Laminaria digitata harvested in March (with high ash content and low carbon to nitrogen (C:N) ratio) and September (with low ash content and high C:N ratio). Washing of L. digitata harvested in March with hot water (defined as 40 °C) removed 54% of the ash and improved the volatile solids (VS) content by 31% leading to an improved biomethane yield of 282 L CH4 kg VS−1. This pre-treatment affected a 16% increase in biodegradability, reduced salt accumulation in the digestate by 54%, and increased specific methane yield per wet weight by 25%. This level of effect was not noted for seaweed harvested in September, when the biodegradability is higher.

Butanol fermentation of the brown seaweed Laminaria digitata by Clostridium beijerinckii DSM-6422

Seaweed represents an abundant, renewable, and fast-growing biomass resource for 3rd generation biofuel production. This study reports an efficient butanol fermentation process carried out by Clostridium beijerinckii DSM-6422 using enzymatic hydrolysate of the sugar-rich brown seaweed Laminaria digitata harvested from the coast of the Danish North Sea as substrate. The highest butanol yield (0.42g/g-consumed-substrates) compared to literature was achieved, with a significantly higher butanol:acetone-butanol-ethanol (ABE) molar ratio (0.85) than typical (0.6). This demonstrates the possibility of using the seaweed L. digitata as a potential biomass for butanol production. For the first time, consumption of alginate components was observed by C. beijerinckii DSM-6422. The efficient utilization of sugars and lactic acid further highlighted the potential of using this strain for future development of large-scale cost-effective butanol production based on (ensiled) seaweed.

Integrated bioethanol and protein production from brown seaweed Laminaria digitata

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.

Brown seaweed processing: enzymatic saccharification of Laminaria digitata requires no pre-treatment

This study assesses the effect of different milling pre-treatments on enzymatic glucose release from the brown seaweed Laminaria digitata having high glucan (laminarin) content. Wet refiner milling, using rotating disc distances of 0.1–2 mm, generated populations of differently sized pieces of lamina having decreasing average surface area (100–0.1 mm2) with increased milling severity. Higher milling severity (lower rotating disc distance) also induced higher spontaneous carbohydrate solubilization from the material. Due to the seaweed material consisting of flat blades, the milling did not increase the overall surface area of the seaweed material, and size diminution of the laminas by milling did not improve the enzymatic glucose release. Milling was thus not required for enzymatic saccharification because all available glucose was released even from unmilled material. Treatment with a mixture of alginate lyase and a cellulase preparation (Cellic®CTec2) on large-sized milled material released all available glucose within 8 h. Application of the cellulase preparation alone released only half of the available glucose. The alginate lyase catalysis apparently induced selective removal of alginate to improve the cellulase catalyzed degradation of laminarin and cellulose in the material.

Effects of polysaccharide rich extracts obtained from the brown seaweed Laminaria digitata on human microbiota in an in vitro model of the distal colon

Effects of polysaccharide rich extracts obtained from the brown seaweed Laminaria digitata on human microbiota in an <i>in vitro</i> model of the distal colon

The impact and mode of action of phenolic compounds extracted from brown seaweed on mixed anaerobic microbial cultures.

This study discusses the effect of phenolic compounds extracted from brown seaweed (phlorotannins) on mixed microbial cultures found in anaerobic systems. Assays were conducted with phloroglucinol as the nonpolymerized form of phlorotannin and with phlorotannins extracted from the brown seaweed Laminaria digitata. Electron micrographs revealed that phlorotannins induce significant extra- and intracellular effects upon cells, with the disruption of cell membranes observed with most micro-organisms. Microscopy results were further confirmed by cell membrane leakage assays demonstrating that phloroglucinol strongly affects cell membrane permeability. However, cell membrane leakage could not be observed with phlorotannins as the cell suspension immediately started to coagulate and impaired spectrophotometric measurements. Results suggest that the bactericidal activity of phlorotannins is a function of the level of polymerization of the compounds. By monitoring intermediary compounds during the anaerobic digestion of phlorotannins, it was also found that higher energy consumption is required by micro-organisms for survival under stress induced by phlorotannins. The successful anaerobic degradation of brown seaweed is thus likely to be dependant on the concentration of phenolic compounds present and their bactericidal effect on micro-organisms. This is the first article to posit a probable mode of action for the antimicrobial effect of phlorotannins.

Effect of alginate on satiation, appetite, gastric function, and selected gut satiety hormones in overweight and obesity.

Lack of control of food intake, excess size, and frequency of meals are critical to the development of obesity. The stomach signals satiation postprandially and may play an important role in control of calorie intake. Sodium alginate (based on brown seaweed Laminaria digitata) is currently marketed as a weight loss supplement, but its effects on gastric motor functions and satiation are unknown. We evaluated effects of 10 days treatment with alginate or placebo on gastric functions, satiation, appetite, and gut hormones associated with satiety in overweight or obese adults. We conducted a randomized, 1:1, placebo-controlled, allocation-concealed study in 48 overweight or obese participants with excluded psychiatric comorbidity and binge eating disorder. All underwent measurements of gastric emptying (GE), fasting, and postprandial gastric volumes (GVs), postprandial satiation, calorie intake at a free choice meal and selected gut hormones after 1 week of alginate (three capsules vs. matching placebo per day, ingested 30 min before the main meal). Six capsules were ingested with water 30 min before the GE, GV, and satiation tests on days 8-10. There were no treatment group effects on GE or volumes, gut hormones (ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY)), satiation, total and macronutrient calorie intake at a free choice meal. There was no difference detected in results between obese and overweight patients. Alginate treatment for a period of 10 days showed no effect on gastric motor functions, satiation, appetite, or gut hormones. These results question the use of short-term alginate treatment for weight loss.

The Absorption of Zinc and Other Metals by the Brown Seaweed Laminaria Digitata

The absorption of zinc has been studied in the brown seaweed Laminaria digitata (Huds.) Lamour., with use of the radionuclide 65Zn and atomic absorption analysis. No evidence of the regulation of zinc by the plant has been found. Absorption of zinc or 65Zn is a gradual process of accumulation which may continue throughout the life of the plant and is not accompanied by the exchange of zinc. As a result, once it has been absorbed, zinc or 65Zn shows little tendency to be lost from the plant. The amounts of zinc or 65Zn which can be accumulated from sea water containing different concentrations of zinc and the effects on these of growth, light and competition from other metals have been studied. Possible sites at which zinc might be bound have been discussed, and the experimental results have been compared with the situation found in the field.

The mechanism of iodide accumulation by the brown sea weed Laminaria digitata. II. Respiration and iodide uptake.

Iodide absorption by fresh, summer Laminaria digitata frond was accompanied by about a fivefold increase in the rate of oxygen consumption. Between approximately 3 and 6 molecules of O 2 were consumed for each iodide ion absorbed by the tissue and the respiratory quotient, whether measured in the presence or absence of iodide, lay between 0·9 and 1·1 (mean 0·94). It is argued that: (1) The iodide-stimulated respiration must occur principally near the surface of the frond, though this localization is not due to the limited diffusibility of oxygen. (2) Iodide absorption is connected with the oxidation of a carbohydrate-like compound or compounds. (3) The absorption of iodide is associated with a rate-limiting process for the oxidation of the compound or compounds. (4) Between one and two iodide ions are absorbed for each six-carbon unit oxidized. (5) Probably only one or two reactions in the oxidation of each six-carbon unit is involved in iodide absorption, one of these reactions being the rate limiting process governing the oxidation.

The mechanism of iodide accumulation by the brown sea weed Laminaria digitata; the uptake of 131 I.

Laminaria digitatafrond rapidly absorbs radio-active iodine from aerated sea water. The absorption rate remains substantially constant throughout experiments lasting 2 or 3 h. After an hour the weed shows about thirty times as much activity as an equal volume of the surrounding sea water. The uptake rate is reduced if inactive iodide be added to the sea water to give a concentration of 10-4M. The further observations support the view that iodide uptake proceeds by: (1) the oxidation of iodide to I2, (2) the diffusion of I2(or its hydrolysis product HIO) into the tissues, and finally (3) the reduction of the penetrant I2, or HIO within the tissues. Iodide added to aerated sea water is rapidly oxidized to I2in the presence of the weed and the agents and conditions mentioned in the succeeding paragraph as slowing or halting radio-iodine uptake have also been shown to prevent elementary iodine being formed.131I absorption is slowed or halted by thiocyanate, thiosulphate, metabisulphite, catechol, tyrosine and pyruvate in concentrations of 1–3 x 10-3M. The full effect of these inhibitors persists only so long as they are present in the sea water about the weed. If an excess of inactive iodide be added to sea water, or if the weed be kept in the dark, then an atmosphere of N2interrupts the uptake of131I; darkness alone, however, has no immediate influence on radio-iodine uptake. When elementary iodine rather than iodide be added to weed maintained in the dark under N2a rapid absorption of activity is initiated. After the weed has been placed in iodide-enriched sea water, analyses indicate that about three-quarters of the element lost from the water occurs in the tissues as iodide.