The response of tobacco plants genetically engineered with the AtTPS1 gene to stress induced by excess Cu and Cd was evaluated in hydroponic solution (100 and 400 lM Cu and 50 and 200 lM Cd) after a 48 h exposure. Two transgenic lines, transformed with the AtTPS1 (trehalose-6-phosphate synthase) gene from Arabidopsis, with different levels of trehalose-6-phosphate synthase expression (B5H, higher and B1F, lower...
Oil palm empty fruit bunches (OPEFB) fibre, a by-product generated from non-woody, tropical perennial oil palm crop was evaluated for xylooligosaccharides (XOS) production. Samples of OPEFB fibre were subjected to non-isothermal autohydrolysis treatment using a temperature range from 150 to 220 ºC. The highest XOS concentration, 17.6 g/L which relayed from solubilisation of 63 g/100 g xylan was achieved at 210...
Xylitol can be obtained from the pentose-rich hemicellulosic fraction of agricultural residues, such as extracted olive pomace, by fermentation. Dilute acid hydrolysis of lignocellulosic materials, produces the release of potential inhibitory compounds mainly furan derivatives, aliphatic acids, and phenolic compounds. In order to study the potential on the increase of the hydrolysate fermentability, detoxificat...
O desenvolvimento de processos que permitam o fraccionamento eficiente da biomassa (tradicionalmente designados por pré-tratamentos) constitui uma parte muito significativa do esforço científico que tem sido feito para a transformação das biorrefinarias numa realidade industrial. Este artigo apresenta uma breve revisão dos processos de fraccionamento, sendo dada particular atenção a processos emergentes, discu...
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...
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...
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,...
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...
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