Anaerobic digestion and gasification of seaweed

The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, with over 70 years of sometimes intensive research and considerable financial investment. A wide range of unit operations can be combined to produce algal biofuel, but as yet there is no successful commercial system producing such biofuel. This suggests that there are major technical and engineering difficulties to be resolved before economically viable algal biofuel production can be achieved. Both gasification and anaerobic digestion have been suggested as promising methods for exploiting bioenergy from biomass, and two major projects have been funded in the UK on the gasification and anaerobic digestion of seaweed, MacroBioCrude and SeaGas. This chapter discusses the use of gasification and anaerobic digestion of seaweed for the production of biofuel

Comparison of Different Membrane Filtration Systems for Recovering Active Phenolic Compounds from the European Spread Macroalga Sargassum muticum

International audienceSargassum muticum is an invasive macroalga that uncontrollable widely grows on the European Atlantic coasts. This macroalga is particularly rich in phenolics (phlorotan-nins) presenting biological activities such as antioxidant, radical-scavenging, antibacte-rial, photoprotective properties, etc. Among the diversity of metabolites produced by the species, phenolic compounds could constitute one of the potential ways of valorization of Sargassum muticum.For the needs of the study, algae were harvested along a latitudinal gradient in Norway, Ireland, France, Spain and Portugal.After extraction, the highest phenolic contents and bioactivities were measured for the samples coming from Norway and Portugal. Consequently, both these countries have been retained in the present work.The extracts are composed of a “pool” of phenolic compounds of molecular weight varying, according to the literature, from 126 Da (phloroglucinol) to 650 kDa. But the most common compounds are comprised between 10 and 100 kDa. With the aim of concentrating and eventually fractionating (i.e. isolating the most active fractions) the phenolic extracts of Sargassum muticum, a few membranes of Molecular Weight Cut-Off 10 kDa were chosen. These membranes were tested by using different technologies: ultrafiltration, centrifugal tube and dialysis.Results show that there is no significant activity in the permeates signifying that the retention rate is about 100 % for the active fractions. Concerning the retentates, results show clearly an increase of the total phenolic contents as well as antioxidant and radical scavenging activities. The best performances are obtained with the centrifugal tubes using 10 kDa membranes

Use of membrane systems for recovering phenolic compounds from the invasive macroalgae Sargassum muticum

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Green improved processes to extract bioactive phenolic compounds from brown macroalgae using Sargassum muticum as model

A comparative study between “alternative” extraction processes such as centrifugal partition extraction (CPE), supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) and classical solid/liquid used in the laboratory are currently focusing on the efficiency (selectivity and productivity) to obtain bioactive phenolic compounds from the phaeophyte Sargassum muticum model. The choice of the best process was based on several measurements: (i) the total phenolic content measured by the colorimetric Folin–Ciocalteu assay, (ii) radical scavenger and antioxidant activities assessed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, and the β-carotene bleaching method and finally (iii) the method productivity. Irrespective of the solvent used in the processes, alternative methods are always sharply more effective than classical ones. With the exception of SFE which does not allow extracting the totality of the active phenolic compounds, two of the other extraction methods were particularly promising. First, CPE afforded the most important yields in concentrated phenolic compounds (PC) (22.90±0.65%DW) also displaying the best activities (0.52±0.02 and 0.58±0.19 mg/mL for IC50 and AAC700, respectively). Secondly, PLE using an EtOH:water mixture 75:25 (v/v) allowed a good PC extraction (10.18±0.25%DW) with huge efficiency. Despite a lesser activity of the extracts (0.77±0.01 and 1.59±0.15 mg/mL for IC50 and AAC700, respectively) PLE is a green process and potentially complies European norms requirements for the prospective valorization of phenolic compounds from S. muticum in Brittany.This study is part of the Ph.D. thesis work carried out by the first author within the Laboratoire des Sciences de l'Environnement Marin (LEMAR UMR 6539) set at the IUEM (UBO-UEB). It was supported by the Ministère de l'Education Nationale, de l'Enseignement Supérieur et de Recherche (UBO allocation).Peer Reviewe

Rapid geographical differentition of a european spred brown algae

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Pre-clinical study of 21 approved drugs in the mdx mouse

International audienceDuchenne muscular dystrophy, a genetic disease caused by the absence of functional dystrophin, remains without adequate treatment. Although great hopes are attached to gene and cell therapies, identification of active small molecules remains a valid option for new treatments. We have studied the effect of 20 approved pharmaceutical compounds on the muscles of dystrophin-deficient mdx5Cv mice. These compounds were selected as the result of a prior screen of 800 approved molecules on a dystrophin mutant of the invertebrate animal model Caenorhabditis elegans. Drugs were administered to the mice through maternal feeding since 2weeks of life and mixed in their food after the 3rd week of life. The effects of the drugs on mice were evaluated both at 6weeks and 16weeks. Each drug was tested at two concentrations. Prednisone was added to the molecule list as a positive control. To investigate treatment efficiency, more than 30 histological, biochemical and functional parameters were recorded. This extensive study reveals that tricyclics (Imipramine and Amitriptyline) are beneficial to the fast muscles of mdx mice. It also highlights a great variability of responses according to time, muscles and assays

Biochemical and antiviral activities of enzymatic hydrolysates from different invasive French seaweeds

International audienceProliferations of green, brown and red algae appear in shallow sandy bays in North Brittany (France), and they represent a real economic constraint for the affected communities. In addition to the nuisance for residents and tourist activity, the communities must carry out systematic collection. The collected algae are spread on agricultural land spreading or composted, but these solutions reach their limits rapidly, bringing little added value to the collected algae. Seaweeds are potentially excellent sources of bioactive metabolites that could represent useful leads in the development of new functional ingredients in pharmaceutical and cosmetic industries. The aim of this study was to propose the use of an enzyme-assisted extraction as a tool to improve the extraction efficiency of antiviral compounds from three invasive French seaweeds. We selected the red Solieria chordalis, the green Ulva sp. and the brown Sargassum muticum as models for these experiments. In comparison with water extraction at 50 °C for the same time of treatment, enzymatic hydrolysis increased the yields. The data suggest the potential of enzymatic hydrolysis for producing active fractions in the function of the algal biomass, the behaviour of the cell wall, the selectivity and the action of the enzyme. Enzymatic hydrolysis appeared less effective for polyphenol recovery, but was a promising softer technique for recovering proteins, neutral sugars, uronic acids and sulphate groups. The solvent-free process, higher extraction rate and higher yields, coupled to time-saving and lower cost, make this method economical and sustainable. By using a cell viability assay, all hydrolysate fractions tested were shown to be non-toxic to Vero cells. After 3 days of treatment, no microscopically visible alteration of normal cell morphology was observed even at 500 μg mL−1. S. chordalis extracts have an effective antiviral activity with EC50 between 23.0 and 101.1 μg mL−1 at a multiplicity of infection of 0.001 ID50/cells; 100 % and 98 % cellular protection were obtained for 500 μg mL−1 of hydrolysate extracts carbohydrase C3 and blank, respectively. Other extracts from S. chordalis inhibited viral production less effectively