Vol.7, No.4, 2019-Table of Contents
  • Biorefinery of Rice Husk to Obtain Functionalized Bioactive Compounds
  • Abstract The biomass industrialization valorisation of grains and cereals is considered an opportunity for the countries where agro-industrial activity is one of its main economic activities, rendering new higher-value products with a concomitant solution to waste accumulation issues. To that end, in this work we describe and characterise bioactive compounds generation from rice husk by semi-solid fermentation, obtained from 500 g of the material at room temperature and 60% humidity with mixed cultures of Phanerochaete chrysosporium and Gloeophyllum trabeum. The extract was evaluated in different situations: murine mammary tumour cells (4T1), normal cells (NIH 3T3) and in Lactobacillus acidophilus, and Trichoderma… More
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  • Miscibility of Poly(hydroxybutyrate)/Poly(vinyl alcohol) Melt Blends Plasticized With Glycerol
  • Abstract Poly(hydroxybutyrate)/poly(vinyl alcohol) (PHB/PVA) blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA. The PHB/PVA-glycerol compositions were 90:10, 75:25 and 50:50 w/w, being the concentration of glycerol in the PVA mixture of 10 wt %. The blends were characterized by infrared spectroscopy, dynamic-mechanical thermal analysis, and scanning electron microscope of the fragile fractured surface. The results showed one single phase blend, indicating miscibility corroborated by the presence of a single glass transition temperature. The blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol… More
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  • Performance Comparison of Commercial and Home-Made Lipases for Synthesis of Poly(δ-Valerolactone) Homopolymers
  • Abstract Novozyme 435, which is the commercially available immobilized form of Candida antarctica lipase B, has been successfully conducted ring opening polymerization of lactones in organic solvents. In this paper, it was aimed to introduce an alternative biocatalyst for Novozyme 435. Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption (with a specific activity of 4.4 U/mg) was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone) synthesis in the present work. Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations. The resulting products were characterized spectroscopically and thermally.… More
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  • Structural Characterization and Antioxidant Activity of Lignin Extracted from Ficus Carica L.
  • Abstract The most abundant phenolic biopolymer in the biosphere is the lignin. This phenolic biopolymer commonly exists in combination with polysaccharides and other cell wall components. In this study, the solvent system dioxane-water is used to extract lignin, which is considered as unaltered native lignin. The dioxane lignin extracted from fig stems was characterized regarding to its structural feature, quantification of its functional groups, molecular weight, and evaluation of its thermal properties. Purity and molecular weight distribution of the studied lignin indicated that isolated lignin contained a low amount of sugar (c.a. 19%) and had a high weight-average molecular weight (10… More
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  • Ecofriendly E-Nose Based in PLA and Only 0.3 wt% of CNTs
  • Abstract In this work, conductive polymer nanocomposites were developed based on a biodegradable and biobased polymer (poly (lactic acid)), with the incorporation of only 0.3 wt% of carbon nanotubes (CNTs) to be used as volatile solvent sensors. The correct dispersion of the nanofiller was achieved thanks to a CNT non-covalent modification with an azo-dye (disperse orange 3) which allowed to reach the percolation for electric conduction in values as low as 0.3 wt%. The chemo-resistive properties of the developed sensors were investigated by exposure to organic vapors (ethanol, tetrahydrofuran and toluene) and water vapor, showing good selectivity. In addition, considering the… More
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  • Lactic Acid Fermentation from Coffee Ground Waste Hydrolysate by Lactobacillus rhamnosus
  • Abstract Lactic acid is an important organic acid that is widely used in the food, pharmaceutical, and cosmetic industries. Lactic acid was produced from coffee ground waste which contains fermentable sugars and is increasingly generated from our daily dietary life. Among 114 strains of Lactobacillus species, Lactobacillus rhamnosus ATCC 10863 was selected for the production of lactic acid from coffee ground waste. Through alkali pretreatment and saccharification, cellulose and hemicellulose in coffee ground waste were converted into fermentable sugars. Pretreatment experiments were conducted at various alkali solution, concentrations, and times. Alkali pretreatment with 35 g/L of KOH at 121oC for 60… More
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  • Isolation and Characterization of Cellulose Nanofibers from Argentine Tacuara Cane (Guadua Angustifolia Kunth)
  • Abstract New trends in the area of material improvement are the use of natural nano-charges from renewable biomass, improving the value and sustainability of our country’s natural products. Bamboo is widely used in many countries of the world, although in Argentina, despite being commercialized and exported for the manufacture of wood floors, it goes unnoticed despite having native species. Therefore, researchers identified the native and exotic species present in our country and are working on novel uses. In this context, it is proposed the Argentine Tacuara Cane (Guadua Angustifolia Kunth), endemic plant as a new source of nanocellulosic materials, where stem… More
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  • Oxidative Degradation of Thermoplastic Starch Induced by UV Radiation
  • Abstract Among biopolymers, thermoplastic starch (TPS) is a good candidate to obtain biomaterials because of its natural origin, biodegradable character, and processability. Exposure to ultraviolet (UV) radiation causes significant degradation of starch-based materials, inducing photooxidative reactions which result in breaking of polymer chains, production of free radical, and reduction of molar mass. These changes produce a deterioration of TPS mechanical properties, leading to useless materials after an unpredictable time. In this work, changes induced on TPS by UV radiation, analyzing structural properties and mechanical behavior, are studied. TPS was obtained through thermo-mechanical processing of native corn starch in the presence of… More
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  • Biocomposites Based on Thermoplastic Starch and Granite Sand Quarry Waste
  • Abstract Granite stone is a by-product of the rock crushing manufacturing. An industrial waste in powder form that causes health problems and environmental pollution. Fine particles fraction can be used as a partial replacement of sand in concrete manufacture. In this work, an alternative exploitation of this waste fraction is proposed. Granite sand (GS) with particles mean size of ~1 μm was employed as thermoplastic starch (TPS) filler at different concentrations. Biocomposites were obtained by melt-mixing and thermo-compression, achieving translucent and easy to handle films. A good GS dispersion within the matrix was evidenced by SEM. Mineral presence induced a shift… More
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