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Julia Marinnavarro - One of the best experts on this subject based on the ideXlab platform.

  • revalorization of cellulosic wastes from posidonia oceanica and arundo donax as catalytic materials based on affinity immobilization of an engineered β galactosidase
    Food Hydrocolloids, 2020
    Co-Authors: Maria Jose Fabra, Isabel Sebapiera, David Talensperales, Amparo Lopezrubio, Julio Polaina, Julia Marinnavarro
    Abstract:

    Abstract Catalytic materials obtained by enzyme immobilization have multiple potential applications in the food industry. The choice of the immobilization method and support may be critical to define the properties of the immobilized enzyme compared to the soluble form. Although the use of immobilized enzymes shows multiple advantages, their catalytic efficiency is compromised in many instances. Molecular engineering techniques have been used to generate hybrid proteins where the enzyme of interest is fused to a module with affinity to a specific biopolymer. Binding of the hybrid TmLac-CBM2 protein, in which the β-galactosidase from Thermotoga maritima is fused to a carbohydrate-binding module from Pyrococcus furiosus, to cellulosic material from Aquatic Biomass wastes (such as Posidonia oceanica and Arundo donax) has been assayed. Both species generate environmental wastes that could be revalorized if converted into bioactive materials. Cellulose cryogels, but not films, from P. oceanica were able to bind the TmLac-CBM2 hybrid, with a higher immobilization yield (90%) than that from A. donax cellulose cryogels (60%). However, fractions containing also hemicellulose were less effective as immobilization supports in both cases, with yields of 47% and 30%, respectively. Cellulose cryogels loaded with β-galactosidase were able to hydrolyse lactose with the same efficiency as the free form of the enzyme. In contrast, enzyme-loaded cellulose films were inactive. This study represents a proof of concept for the valorisation of cellulosic wastes as bioactive materials. Furthermore, it provides information about the interaction specificity between the binding module and the cellulosic support, useful for other enzymes.

Bruno Nunes - One of the best experts on this subject based on the ideXlab platform.

  • the impact of paracetamol on selected biomarkers of the mollusc species corbicula fluminea
    Environmental Toxicology, 2014
    Co-Authors: Fatima Brandao, Joana Luisa Pereira, Fernando Goncalves, Bruno Nunes
    Abstract:

    The Asian clam Corbicula fluminea is an invasive bivalve that has recently spread in Europe and currently represents a large portion of the Aquatic Biomass in specific areas. Because of the impacts that the species may have in invaded ecosystems, increased knowledge on the physiologic features of the species life-cycle under different environmental scenarios (e.g., contamination events) is critical to understand the dynamics of the invasion and resulting ecosystem imbalance. The presence of pharmaceutical residues in the Aquatic environment has recently received great attention since high levels of contamination have been found, not only in sewage treatment plant effluents, but also in open waters. The present article reports toxicological biochemical effects of paracetamol to Corbicula fluminea following short- and long-term exposures. Oxidative stress parameters were specially focused namely catalase (CAT), glutathione S-transferases (GSTs), and glutathione reductase (GRed). The effect of tested substances on lipid peroxidation was also investigated. Paracetamol did not induce alterations on CAT activity, caused a significant decrease of GSTs activity following short- and long-term exposure (LOEC values of 532.78 mg L−1 and 30.98 μg L−1, respectively), and was responsible for a significant and dose-dependent decrease of GRed activity in short- and long-term exposures. These results indicate that exposure to paracetamol can provoke significant alterations on the cellular redox status of C. fluminea. 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 74–83, 2014.

Yusuke Edashige - One of the best experts on this subject based on the ideXlab platform.

  • syngas production by co2 o2 gasification of Aquatic Biomass
    Fuel Processing Technology, 2013
    Co-Authors: Toshiaki Hanaoka, Shou Hiasa, Yusuke Edashige
    Abstract:

    Abstract In the gasification of an Aquatic Biomass with He/CO2/O2, the effects of the concentration of CO2 and O2 in the gasifying agent and the feeding rate on the gasification behavior were investigated using a downdraft fixed-bed gasifier at 900 °C. Using CO2/O2 as the gasifying agent led to an increase in the conversion to gas and the syngas (CO + H2) content because the gasification of char with CO2 (C + CO2 → 2CO) and the decomposition of tarry compounds were promoted. Increasing CO2 content led to the increase in the conversion to gas and CO content and the decrease in the H2 content. With increasing O2 content, contents of CO and H2 increased while the conversions to gas remained almost constant. Especially with CO2/O2 = 45/55 vol.%, the conversion to gas was 94.0 C-mol% and the syngas content exhibited a maximum value of 69.7 vol.%. As the feeding rate was decreased, contents of CO and H2 decreased while the conversion to gas remained almost constant. The nitrogen atoms in the feedstock were mainly converted to form N2. H2S and COS were the main sulfurous gases. The sulfur content in the char was much higher than that in the feedstock.

  • syngas production by gasification of Aquatic Biomass with co2 o2 and simultaneous removal of h2s and cos using char obtained in the gasification
    Biomass & Bioenergy, 2013
    Co-Authors: Toshiaki Hanaoka, Shou Hiasa, Yusuke Edashige
    Abstract:

    Abstract Applicability of gulfweed as feedstock for a Biomass-to-liquid (BTL) process was studied for both production of gas with high syngas (CO + H 2 ) content via gasification of gulfweed and removal of gaseous impurities using char obtained in the gasification. Gulfweed as aqueous Biomass was gasified with He/CO 2 /O 2 using a downdraft fixed-bed gasifier at ambient pressure and 900 °C at equivalence ratios (ER) of 0.1–0.3. The syngas content increased while the conversion to gas on a carbon basis decreased with decreasing ER. At an ER of 0.1 and He/CO 2 /O 2  = 0/85/15%, the syngas content was maximized at 67.6% and conversion to gas on a carbon basis was 94.2%. The behavior of the desulfurization using char obtained during the gasification process at ER = 0.1 and He/CO 2 /O 2  = 0/85/15% was investigated using a downdraft fixed-bed reactor at 250–550 °C under 3 atmospheres (H 2 S/N 2 , COS/N 2 , and a mixture of gases composed of CO, CO 2 , H 2 , N 2 , CH 4 , H 2 S, COS, and steam). The char had a higher COS removal capacity at 350 °C than commercial activated carbon because (Ca,Mg)S crystals were formed during desulfurization. The char simultaneously removed H 2 S and COS from the mixture of gases at 450 °C more efficiently than did activated carbon. These results support this novel BTL process consisting of gasification of gulfweed with CO 2 /O 2 and dry gas cleaning using self-supplied bed material.

Shou Hiasa - One of the best experts on this subject based on the ideXlab platform.

  • syngas production by co2 o2 gasification of Aquatic Biomass
    Fuel Processing Technology, 2013
    Co-Authors: Toshiaki Hanaoka, Shou Hiasa, Yusuke Edashige
    Abstract:

    Abstract In the gasification of an Aquatic Biomass with He/CO2/O2, the effects of the concentration of CO2 and O2 in the gasifying agent and the feeding rate on the gasification behavior were investigated using a downdraft fixed-bed gasifier at 900 °C. Using CO2/O2 as the gasifying agent led to an increase in the conversion to gas and the syngas (CO + H2) content because the gasification of char with CO2 (C + CO2 → 2CO) and the decomposition of tarry compounds were promoted. Increasing CO2 content led to the increase in the conversion to gas and CO content and the decrease in the H2 content. With increasing O2 content, contents of CO and H2 increased while the conversions to gas remained almost constant. Especially with CO2/O2 = 45/55 vol.%, the conversion to gas was 94.0 C-mol% and the syngas content exhibited a maximum value of 69.7 vol.%. As the feeding rate was decreased, contents of CO and H2 decreased while the conversion to gas remained almost constant. The nitrogen atoms in the feedstock were mainly converted to form N2. H2S and COS were the main sulfurous gases. The sulfur content in the char was much higher than that in the feedstock.

  • syngas production by gasification of Aquatic Biomass with co2 o2 and simultaneous removal of h2s and cos using char obtained in the gasification
    Biomass & Bioenergy, 2013
    Co-Authors: Toshiaki Hanaoka, Shou Hiasa, Yusuke Edashige
    Abstract:

    Abstract Applicability of gulfweed as feedstock for a Biomass-to-liquid (BTL) process was studied for both production of gas with high syngas (CO + H 2 ) content via gasification of gulfweed and removal of gaseous impurities using char obtained in the gasification. Gulfweed as aqueous Biomass was gasified with He/CO 2 /O 2 using a downdraft fixed-bed gasifier at ambient pressure and 900 °C at equivalence ratios (ER) of 0.1–0.3. The syngas content increased while the conversion to gas on a carbon basis decreased with decreasing ER. At an ER of 0.1 and He/CO 2 /O 2  = 0/85/15%, the syngas content was maximized at 67.6% and conversion to gas on a carbon basis was 94.2%. The behavior of the desulfurization using char obtained during the gasification process at ER = 0.1 and He/CO 2 /O 2  = 0/85/15% was investigated using a downdraft fixed-bed reactor at 250–550 °C under 3 atmospheres (H 2 S/N 2 , COS/N 2 , and a mixture of gases composed of CO, CO 2 , H 2 , N 2 , CH 4 , H 2 S, COS, and steam). The char had a higher COS removal capacity at 350 °C than commercial activated carbon because (Ca,Mg)S crystals were formed during desulfurization. The char simultaneously removed H 2 S and COS from the mixture of gases at 450 °C more efficiently than did activated carbon. These results support this novel BTL process consisting of gasification of gulfweed with CO 2 /O 2 and dry gas cleaning using self-supplied bed material.

Ali Traissi - One of the best experts on this subject based on the ideXlab platform.

  • production and characterization of lemna minor bio char and its catalytic application for biogas reforming
    Biomass & Bioenergy, 2012
    Co-Authors: Nazim Muradov, Beatriz Fidalgo, Amit Gujar, Nathaniel Garceau, Ali Traissi
    Abstract:

    Abstract Pyrolysis of fast-growing Aquatic Biomass - Lemna minor (commonly known as duckweed) with the emphasis on production, characterization and catalytic application of bio-char is reported in this paper. The yield of bio-char was determined as a function of L. minor pyrolysis temperature and sweep gas flow rate. It was found that the pore development during L. minor pyrolysis was not significant and the changes in the reaction conditions (temperature and sweep gas flow rate) did not alter markedly the textural characteristics and BET surface area of the bio-char produced. Thermogravimetric/differential thermogravimetric (TG/DTG) analyses of L. minor and different bio-char samples in inert (helium) and oxidative (air) media showed substantial differences in their TG/DTG patterns. A comparison of scanning electron micrographs (SEM) of L. minor , bio-char and ash indicated that the basic structural features of L. minor remained intact and were not affected by thermolysis. The inorganic ash content of L. minor derived bio-char is significantly higher than that of typical terrestrial (plant) Biomass. The energy dispersive spectroscopic (EDS) analysis of L. minor ash showed that it mostly consisted of silica, and small quantities of Na, K and Ca compounds. The treatment of bio-char with CO 2 at 800 °C increased its BET surface area. It was found that CO 2 -treated bio-char exhibited appreciable initial catalytic activity in biogas reforming.

  • pyrolysis of fast growing Aquatic Biomass lemna minor duckweed characterization of pyrolysis products
    Bioresource Technology, 2010
    Co-Authors: Nazim Muradov, Beatriz Fidalgo, Amit Gujar, Ali Traissi
    Abstract:

    Abstract The aim of this work was to conduct the experimental study of pyrolysis of fast-growing Aquatic Biomass – Lemna minor (commonly known as duckweed) with the emphasis on the characterization of main products of pyrolysis. The yields of pyrolysis gas, pyrolytic oil (bio-oil) and char were determined as a function of pyrolysis temperature and the sweep gas (Ar) flow rate. Thermogravimetric/differential thermogravimetric (TG/DTG) analyses of duckweed samples in inert (helium gas) and oxidative (air) atmosphere revealed differences in the TG/DTG patterns obtained for duckweed and typical plant Biomass. The bio-oil samples produced by duckweed pyrolysis at different reaction conditions were analyzed using GC–MS technique. It was found that pyrolysis temperature had minor effect on the bio-oil product slate, but exerted major influence on the relative quantities of the individual pyrolysis products obtained. While, the residence time of the pyrolysis vapors had negligible effect on the yield and composition of the duckweed pyrolysis products.