Selective production of sugars and glycolaldehyde from agricultural biomass using supercritical water as reaction medium

Introduction Biomass is a renewable and worldwide-distributed carbon resource which has the potential to produce energy, chemicals and fuels for the future sustainable industries [1]. Biobased industries, based on the use of renewable materials and energy, are still in development to success to promote a decentralized production that can be an alternative to the centralized petrochemical production plants. Taking into account the wide range of possibilities for biomass refineries, plant biomass is considered a promising source to replace fossil fuels as feedstock for the sustainable production of fuels, materials and fine chemicals as sugars and added-value compounds as glycolaldehyde [2, 3] that can be obtained via thermochemical processes such as hydrolysis [4]. Glucose would be obtained from cellulose hydrolysis, hemicellulose would release its component sugars and lignin would produce phenolic compounds [5]. Also, glycolaldehyde is the main retro-aldol condensation product from glucose and it is a promising raw material to produce two-carbon building block molecules. For example, ethylene glycol is a widely applied polymer in the plastic and polyester industries. Apart from petroleum, it can be obtained through the hydrogenation of glycolaldehyde by a transition metal catalyst [6, 7]. Therefore, selective hydrolysis of cellulose into glucose and glycolaldehyde is a key process for the effective use of biomass [8]. Please click Additional Files below to see the full abstract

Production of stabilized sub-micrometric particles of carotenoids using supercritical fluid extraction of emulsions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Sub-micrometer particles of carotenoids (beta-carotene and lycopene) suspended in aqueous media were produced by extraction of the organic solvent from the droplets of an oil-in-water emulsion with supercritical CO2. The influence of the process parameters emulsion flow rate, concentration of surfactant/carrier material and pressure on product characteristics was evaluated. Suspensions containing stabilized carotenoids with final particle size of 344-366 nm, encapsulation efficiency of 34-89% and degree of isomerization from carotenoid trans to cis forms in the range of 0.02-15%, were obtained. Independently of the type of carotenoid used, emulsion flow rate influenced the production of suspensions of carotenoids, particularly the encapsulation efficiency and the degree of isomerization. Higher encapsulation efficiencies, but also higher degradations were obtained when beta-carotene was employed instead of lycopene. The concentration of surfactant/carrier material was the only process parameter that influenced the final particle size, while the encapsulation efficiency and degree of isomerization were influenced also by the concentration of surfactant/carrier material and by pressure. (C) 2011 Elsevier B.V. All rights reserved.61167174Fundacion CarolinaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Spanish Ministry of Science and InnovationConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [141894/2009-1