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Industry-based biorefineries

Biocombustíveis: uma oportunidade ou um problema para Portugal 

Apresenta-se nesta curta comunicação a problemática referente à introdução dos biocombustíveis nos transportes em Portugal na sequência da transposição para a legislação nacional das diferentes diretivas europeias (2003 e 2009). A produção de biocombustíveis em território nacional tem vindo a aumentar na sequência da política nacional de promoção dos mesmos embora as matérias-primas utilizadas (oleaginosas) sej...

Deconstruction of the hemicellulose fraction from lignocellulosic materials int...

Hemicelluloses hold a great promise for the production of added-value compounds in the biorefinery framework. Specifically, the xylan-rich hemicelluloses from hardwoods and agro-industrial residues present themselves as effective feedstock choices for the biotechnological production of xylitol. This paper reviews the various hemicellulose structures present in such materials and critically evaluates the availab...

Fermentation of biomass-derived syngas to ethanol and acetate by clostridium l...

In the biochemical pathway of lignocellulosics conversion into fuels, a significant portion of biomass cannot be hydrolysed to fermentable sugars and remains as waste substrate that, due to its recalcitrance, is not converted to ethanol by microorganisms. In terms of product yield, this residual biomass represents renewable feedstock that is being wasted, which contradicts the target of 100% feedstock utilisati...

Production, purification and characterisation of oligosaccharides from olive tr...

The production of oligosaccharides (OS) by olive tree pruning autohydrolysis in the range 170–230 °C was studied. The best results in terms of maximum yield of OS along with a low amount of byproducts were obtained at 180 °C. After purification by preparative gel filtration chromatography a range of OS-fractions with average degree of polymerisation (DP) from 25 to 3 was selected for further characterisation. G...

Implementation of sustainability criteria for biofuels and bioliquids in Portugal

Biological upgrading of wastes from the pulp and paper industry

A process for biological upgrading of recycled paper sludge (RPS) was developed based on the enzymatic hydrolysis of major sludge components (cellulose and xylan) with commercial enzymes and fermentation of the resulting sugars into ethanol or lactic acid with adequate microbial strains. The process was implemented performing both steps sequentially (SHF) or simultaneously (SSF). Cellulosic and hemicellulosic f...

Hydrothermal processing of hardwoods and agro-industrial residues :evaluation o...

Autohydrolysis was used as a pre-treatment method for the selective hydrolysis of hemicelluloses of four lignocellulosic materials: eucalypt wood chips (EWC), corn cobs (CC), wheat straw (WS) and brewery’s spent grain (BSG), and the process was optimized towards the production of xylo-oligosaccharides (XOS). The effects of temperature, both at isothermal (150-190ºC), and non-isothermal (up to 240ºC) conditions,...

Acute toxicity evaluation of several compounds involved in fossil fuels biodesu...

The increasing use of fossil fuels has led to increased emissions of sulphur oxides into the air, which is a major cause of acid rain. Legislation already adopted in 2009 stipulates that the maximum level of sulphur allowed in fuels is only 10 ppm. The process of hydrodesulphurization (HDS) used in refineries is based on very expensive physico-chemical techniques, and has limitations in the removal of organic s...

The pros and cons of the dedicated upgrade of the hemicellulosic sugar stream i...

The challenge of the future integrated biorefineries is the full economically utilization of all biomass components with the simultaneously production of fuels and chemicals, preferably of added-value. This can only be achieved by the selective fractionation of the lignocellulosic biomass into its polymeric components, thus increasing their individual upgradeability to enhance the process economics. To reach th...