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Tyrosinase catalyzes the conversion of tyrosine to dihydroxyphenylalanine quinone, which is the main precursor for the biosynthesis of melanin. The enzyme from Agaricus bisporus, the common button mushroom, was purified and crystallized in two different space groups. Crystals belonging to space group P2(1) (unit-cell parameters a = 104.2, b = 105.0, c = 119.1 angstrom, beta = 110.6 degrees, four molecules per asymmetric unit) diffracted to 3.0 angstrom resolution. Crystals belonging to space group P2(1)2(1)2 (unit-cell parameters a = 104.0, b = 104.5, c = 108.4 angstrom, two molecules per asymmetric unit) diffracted to 2.6 angstrom resolution. It was essential to include 5 mM HoCl3 in all crystallization conditions in order to obtain well diffracting crystals.

The aim of this work was to evaluate the potential of employing biomass resources from different origin as feedstocks for fermentative hydrogen production. Mild-acid pretreated and hydrolysed barley straw (BS) and corn stalk (CS), hydrolysed barley grains (BG) and corn grains (CG), and sugar beet extract (SB) were comparatively evaluated for fermentative hydrogen production. Pretreatments and/or enzymatic hydrolysis led to 27, 37, 56, 74 and 45 g soluble sugars/100 g dry BS, CS, BG, CG and SB, respectively. A rapid test was applied to evaluate the fermentability of the hydrolysates and SB extract. The thermophilic bacterium Caldicellulosiruptor saccharolyticus showed high hydrogen production on hydrolysates of mild-acid pretreated BS, hydrolysates of BG and CG, and SB extract. Mild-acid pretreated CS showed limited fermentability, which was partially due to inhibitory products released in the hydrolysates, implying the need for the employment of a milder pretreatment method. The difference in the fermentability of BS and CS is in strong contrast to the similarity of the composition of these two feedstocks. The importance of performing fermentability tests to determine the suitability of a feedstock for hydrogen production was confirmed.

The biorefinery concept is a very powerful concept to optimise the conversion of biomass resources to value-added products with a minimum loss of energy and mass and a maximum overall value of the production chain. We here report our activities on the application of this concept to valorise the Jatropha curcas L. (JCL) shrub, a (sub)-tropical plant producing a high quality plant oil that may be converted to biodiesel in good yields. Within a research consortium of Dutch and Indonesian researchers, we are exploring high added value outlets for byproducts of the JCL plant (leaves, latex) and seed processing units (press cake). As an example, we here report fast pyrolysis experiments to convert the nut shells to fast pyrolysis oil, a promising second generation biofuel. The fast pyrolysis experiments were carried out in a continuous bench scale pyrolyser at a throughput of 2.27 kg/h at 480 degrees C and atmospheric pressure. The nut shell pyrolysis oil was obtained in 50 wt.% yield, the remainder being char (23 wt.%), gas (17 wt.%) and ash. Relevant product properties of the oil were determined and indicate that the oil is inhomogeneous in nature. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V All rights reserved.

This paper deals with a biorefinery classification approach developed within International Energy Agency (IEA) Bioenergy Task 42. Since production of transportation biofuels is seen as the driving force for future biorefinery developments, a selection of the most interesting transportation biofuels until 2020 is based on their characteristics to be mixed with gasoline, diesel and natural gas, reflecting the main advantage of using the already-existing infrastructure for easier market introduction.This classification approach relies on four main features: (1) platforms; (2) products; (3) feedstock; and (4) processes. The platforms are the most important feature in this classification approach: they are key intermediates between raw materials and final products, and can be used to link different biorefinery concepts. The adequate combination of these four features represents each individual biorefinery system. The combination of individual biorefinery systems, linked through their platforms, products or feedstocks, provides an overview of the most promising biorefinery systems in a classification network. According to the proposed approach, a biorefinery is described by a standard format as platform(s) - products - and feedstock(s). Processes can be added to the description, if further specification is required. Selected examples of biorefinery classification are provided; for example, (1) one platform (C6 sugars) biorefinery for bioethanol and animal feed from starch crops (corn); and (2) four platforms (lignin/syngas, C5/C6 sugars) biorefinery for synthetic liquid biofuels (Fischer-Tropsch diesel), bioethanol and animal feed from lignocellulosic crops (switchgrass).This classification approach is flexible as new subgroups can be added according to future developments in the biorefinery area.

Nucleic acid lateral flow immunoassay (NALFIA) is a method combining molecular biological principle of detection with immunochemical principle of visualisation. Following isolation of DNA from the sample, a duplex PCR with two primer sets, of which one was labelled with biotin and the other with digoxigenin or fluorescein, respectively, was performed. The PCR solution and carbon particles conjugated with avidin are directly added to the nitrocellulose membrane with two test lines of immobilised antibodies specific for digoxigenin and fluorescein. The appearance of a black line indicates the presence of specific amplicon. We would like to present the NALFIA for the simultaneous detection of L. monocytogenes in particular and the genus Listeria in general, in food. Bacteria from the genus Listeria frequently contaminate a large variety of foods. Occurrence of Listeria strains in food may indicate errors in good hygienic and manufacturing practice, only L. monocytogenes is a significant human and animal pathogen responsible for the serious illness listeriosis. Conventional microbiological methods for L. monocytogenes detection are laborious and take several days to achieve a confirmed identification.

Elastin-like polypeptides (ELPs) are biocompatible designer polypeptides with inverse temperature transition behavior in solution. They have a wide variety of possible applications and a potential medical importance. Currently, production of ELPs is done at lab scale in Escherichia coli shake flask cultures. With a view to future large scale production, we demonstrate secreted production of ELPs in methanol-induced fed-batch cultures of Pichia pastoris and purification directly from the culture medium. The production of ELPs by P. pastoris proved to be pH dependent within the experimental pH range of pH 3 to 7, as an increasing yield was found in cultures grown at higher pH. Because ELP produced at pH 7 was partly degraded, a pH optimum for production of ELP was found at pH 6 with a yield of 255 mg of purified intact ELP per liter of cell-free medium.

Stripping gas is generally used to improve hydrogen yields in fermentations. Since CO2 is relatively easy to separate from hydrogen it could be an interesting stripping gas. However, a higher partial CO2 pressure is accompanied with an increased CO2 uptake in the liquid, where it hydrolyses and induces an increased requirement of NaOH to maintain the pH. This enhances the osmotic pressure in the culture by 30%, which inhibited the growth of Caldicellulosiruptor saccharolyticus. indications for this conclusion are: i) inhibition could almost completely be circumvented by reducing the bicarbonate through decreasing the pH (from 6.5 to 5.5), ii) Growth rates were reduced by 60 +/- 10% at an osmotic pressure of 0.218 +/- 0.005 osm/kg H2O independently of the stripping gas, iii) Increased extracellular DNA and protein concentrations were observed as a function of the osmotic pressure. In addition to growth inhibition, the increased sodium bicarbonate in the effluent will contribute to a negative environmental impact when applied at industrial scale. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All lights reserved. (Less)

Non-axenic operation of a 400 L trickle bed reactor inoculated with the thermophile Caldicellulosiruptor saccharolyticus, yielded 2.8 molH 2mol hexose converted. The reactor was fed with a complex medium with sucrose as the main substrate, continuously flushed with nitrogen gas, and operated at 73°C. The volumetric productivity was 22 mmolH2(L filterbed h). Acetic acid and lactic acid were the main by-products in the liquid phase. Production of lactic acid occurred when hydrogen partial pressure was elevated above 2% and during suboptimal fermentation conditions that also resulted in the presence of monoand disaccharides in the effluent. Methane production was negligible. The microbial community was analyzed at two different time points during operation. Initially, other species related to members of the genera Thermoanaerobacterium and Caldicellulosiruptor were present in the reactor. However, these were out-competed by C. saccharolyticus during a period when sucrose was completely used and no saccharides were discharged with the effluent. In general, the use of pure cultures in non-sterile industrial applications is known to be less useful because of contamination. However, our results show that the applied fermentation conditions resulted in a culture of a single dominant organism with excellent hydrogen production characteristics. © 2008 Wiley Periodicals, Inc.

Nanotapes are formed by the co-assembly of triblock peptide copolymers with an amino acid-substituted polythiophene derivative (PTT). The driving force for the assembly is ionic interaction (complex coacervation). These nanotapes were visualized by atomic force microscopy and confocal laser scanning microscopy. The interactions between the triblock peptide copolymers and the PTT are also expressed in the steady state and time resolved fluorescence spectra. The steady-state spectra indicate that upon interaction with the peptide copolymer, the backbone of the PTT adopts a rather twisted, and definitely less, aggregated conformation. The time-resolved fluorescence decay studies further confirm this interpretation. The structure of these nanotapes at the mesoscopic scale depends, among other physical chemical parameters, on the concentrations of its constituents.

We report on the biosynthesis of 65 kDa A¿B¿A triblock copolymers consisting of pH-responsive (acidic) silklike blocks and nonresponsive collagenlike blocks, and we show that at pH values where the silklike blocks become uncharged, these polymers form transparent high-modulus gels, that is, 7¿15 kPa at 8 g·L¿1, that consist of supramolecular nanotapes with a height of 2.8 nm, a width of 14 nm, and an average length of >10 ¿m. At the concentrations employed, both of these protein triblocks essentially form the same structure, irrespective of block order. The amount of product isolated from the extracellular medium is in the gram per liter range. This high yield makes various applications of this promising class of biocompatible materials possible.

Kenaf is grown these days as a minor fibre crop in some Asian countries, but also in the US and recently in Southern European countries such as Italy. The yield of extracted bast fibres is below 1/3 of that of the kenaf stem weight. In the US and Europe a profitable outlet for the remaining woody core is important for economical production of the crop. The use of kenaf core as animal bedding material is considered here as potential market outlet. An important aspect for this application is the moisture absorption capacity of the material. This paper describes evaluation of the water absorption capacity of different kenaf core fractions in comparison with other commercial animal bedding materials like straw and wood shavings. The water absorption of kenaf core particles is shown to be in the range of the other tested materials and especially the soft pith material showed very high absorbency.

A bioinformatics analysis to screen for high-potential sources of angiotensin converting enzyme (ACE) inhibitory peptides was conducted in the area of insect muscle proteins. Vertebrate muscle proteins are reported as good sources of ACE inhibitory peptides, while the research on invertebrate muscle proteins is limited. A phylogenetic tree constructed with actin sequences of both vertebrate and invertebrate species indicated a high homology. Furthermore, a quantitative in silico ACE inhibition analysis suggested that actin proteins of invertebrates have potentials as new sources of ACE inhibitory peptides. On one insect, Bombyx mori, a more detailed in silico analysis was done followed by a small experimental study. The in silico analysis indicated B. mori as a high-potential source of ACE inhibitory peptides and this was supported by the ACE inhibitory activity of the partially purified actin preparation. In conclusion, in food science, in silico analysis can be used as fast initial screening tool to look for high-potential sources of ACE inhibitory peptides and other peptidic bioactivities.

Sowing density and harvest time are considered important crop management factors influencing fibre quantity and quality in hemp (Cannabis sativa). We investigated whether the effects of these factors are essentially different or that both factors affect stem weight and thereby total and long-fibre content. The effects of all combinations of three sowing densities and three harvest times were studied for six different stem parts. Almost 500 samples consisting of stem parts from 50 plants and with a length of 50 cm were tested. Fibres were extracted by a controlled warm-water retting procedure, followed by breaking and scutching. The initial sample weight was fractionated into retting losses, wood, tow and long fibre. In both Italy and the Netherlands, crops were successfully established with different stem densities (99–283 m-2), plant heights (146–211 cm) and stem diameters (4.5–8.4 mm) at harvest. Stem dry matter yields (6.8–11.7 Mg ha-1) increased with a delay in harvest time but were not affected by sowing density. Retting loss percentages were lower in lower stem parts and decreased with later harvest because maturation was associated with increasing amounts of fibre and wood. Within a certain stem part, however, the absolute retting losses were constant with harvest time. Multiple linear regression analyses showed that the amount of fibre in a hemp stem is almost completely determined by the weight and the position of that stem part. When the plant grows, the increase in dry matter is split up into fibres and wood in a fixed way. This total fibre/wood ratio was highest in the middle part of the stem and lower towards both bottom and top. Sowing density and harvest time effects were indirect through stem weight. The long-fibre weight per stem increased with the total fibre weight and hence with stem weight. Stem weight increased with harvest time; as harvest time did not affect plant density, the highest long-fibre yields were obtained at the last harvest time. The long fibre/total fibre ratio was lowest in the bottom 5 cm of the stems but similar for all other parts. Sowing density and harvest time effects again were indirect. Fibre percentages in retted hemp decreased with increasing stem weights towards a level that is presumably a variety characteristic. The dry matter increase between harvests, however, is much more important with respect to total and long-fibre yield

Hyaluronan (HA) is a polysaccharide with high-potential medical applications, depending on the chain length and the chain length distribution. Special interest goes to homogeneous HA oligosaccharides, which can be enzymatically produced using Pasteurella multocida hyaluronan synthase (PmHAS). We have developed a sensitive, simple, and fast method, based on fluorophore-assisted carbohydrate electrophoresis (FACE), for characterization and quantification of polymerization products. A chromatographic pure fluorescent template was synthesized from HA tetrasaccharide (HA4) and 2-aminobenzoic acid. HA4-fluor and HA4 were used as template for PmHAS-mediated polymerization of nucleotide sugars. All products, fluorescent and nonfluorescent, were analyzed with gel electrophoresis and quantified using lane densitometry. Comparison of HA4- and HA4-fluor-derived polymers showed that the fluorophore did not negatively influence the PmHAS-mediated polymerization. Only even-numbered oligosaccharide products were observed using HA4-fluor or HA4 as template. The fluorophore intensity was linearly related to its concentration, and the limit of detection was determined to be 7.4 pmol per product band. With this assay, we can now differentiate oligosaccharides of size range DP2 (degree of polymerization 2) to approximately DP400, monitor the progress of polymerization reactions, and measure subtle differences in polymerization rate. Quantifying polymerization products enables us to study the influence of experimental conditions on HA synthesis.

Much bio-energy can be obtained from wood pruning operations in forests and fruit orchards. Several spatial studies have been carried out for biomass surveys, and many linear programming models have been developed to model the logistics of bio-energy chains. These models can assist in determining the best alternatives for bio-energy chains. Most of these models use network structures built up from nodes with one or more depots, with arcs connecting the depots. Each depot is a source of a certain biomass type. Nodes can also be biomass storage points or production facilities (e.g., power plants) where biomass is used. The arcs in the networks represent transport between depots. In order to combine GIS spatial studies with linear programming models, it is necessary to build a network from a digital map of biomass production centers, such as orchards. Biomass collection points should therefore be defined as sources in the delivery network model. In this work, a mathematical calculation method is developed to select the actual biomass collection points on a map. The database for this model is composed of area surveys of forest and agricultural biomass storage points given in GIS maps (shape files). The limits of the area studied and different types of biomass are defined and located in different layers of the GIS maps. These energy-biomass production maps are overlaid with a 1 km - 1 km grid of the area studied. The result is a grid in which the different types of total available biomass in each quadrant are known. Harvesting and collection costs are also defined. The connections between all n - m quadrants of the area studied are defined by the available road network. Every quadrant is associated with a point on the road network. The selection criteria for sources of biomass (sub-areas) are the following: firstly, a minimum production of available biomass type is required; and secondly, harvesting and collection costs should be minimal. The algorithm provides the location of points where biomass from the associated area can be concentrated. These biomass collection points are then taken as source nodes in the network during the implementation of the logistics models. In the next step, the network is analyzed by linear programming techniques to supply the optimal position of energy plants or factories, given the available biomass sources

We present the rapid and sensitive detection of amplified DNA on a giant magneto-resistance sensor using superparamagnetic particles as a detection label. The one-step assay is performed on an integrated and miniaturized detection platform suitable for application into point-of-care devices. A double-tagged PCR amplification product of the LamB gene of the Escherichia coli bacterium was used to investigate binding kinetics of the assay. We applied magnetic actuation to concentrate the target-particle complexes at the sensor surface and to remove unbound particles from the sensor surface. We achieved biological dose-response curves detecting 4-250 pM amplicon concentrations in a one-step format in total assay times of less than 3 min. Using various tag-antibody combinations specific for one of the individual genes, multi-analyte detection is shown of several antibiotic resistance genes of the food pathogen Salmonella.

Lateral flow (immuno) assays are currently used for qualitative, semiquantitative and to some extent quantitative monitoring in resource-poor or non-laboratory environments. Applications include tests on pathogens, drugs, hormones and metabolites in biomedical, phytosanitary, veterinary, feed/food and environmental settings. We describe principles of current formats, applications, limitations and perspectives for quantitative monitoring. We illustrate the potentials and limitations of analysis with lateral flow (immuno) assays using a literature survey and a SWOT analysis (acronym for "strengths, weaknesses, opportunities, threats"). Articles referred to in this survey were searched for on MEDLINE, Scopus and in references of reviewed papers. Search terms included "immunochromatography", "sol particle immunoassay", "lateral flow immunoassay" and "dipstick assay".

Carbohydrates occur in food as natural constituents or are added as ingredients. In the last decade a number of novel dietary carbohydrates have been introduced as ingredients for food applications, responding to the growing awareness among consumers of the link between health and diet. One important group is formed by the non-digestible oligosaccharides (NDOs) which may function as prebiotics. In many studies it has been shown that prebiotics in the diet positively influence the human intestinal microbiota. It is envisaged that this will balance the microbial composition in the gastrointestinal tract in favor of health promoting genera such as Bifidobacterium and Lactobacillus . In this review we will focus on the degradation of (potential) prebiotics, derived from plant (poly)saccharides, by bifidobacterial glycoside hydrolases. In addition the possibilities to use or produce new classes of NDOs using the most important glycoside hydrolases from Bifidobacterium sp. will be discussed. Industrial relevance Carbohydrates occur in food as natural constituents or are added as ingredients or additives. In the last decade a number of novel dietary carbohydrates have been introduced as ingredients for food applications, responding to the growing awareness among consumers of the link between health, nutrition, and diet. The food industry is continuously seeking for new opportunities to design new functional foods. One important group is non-digestible oligosaccharides (NDOs) which may function as prebiotics. In many studies it has been shown that prebiotics (and/or probiotics) in the diet positively influence the human intestinal microbiota. It is envisaged that this will balance the microbial composition in the gastrointestinal tract in favor of health promoting genera such as Bifidobacterium and Lactobacillus . To understand how these bacteria can grow on these carbon sources, knowledge of the carbohydrate-modifying enzymes is needed. In this manuscript we will focus on the degradation of (potential) prebiotics by bifidobacterial glycoside hydrolases by exploring the genome sequences of bifidobacteria. Next to that the possibilities to use or produce new classes of NDOs exploiting the most important carbohydrate modifying enzymes in bifidobacteria, in particular carbohydrases with transglycosylation activity, is discussed. In addition, approaches to use and improve carbohydrate-modifying enzymes in (potential) prebiotic design will also be presented. For innovation it is important to look for new opportunities to produce new products. The carbohydrases from bifidobacteria can have different roles like synthesis and degradation of prebiotics. Combining the knowledge of the biochemical characterization of the carbohydrases and exploring the genome sequences of gut bacteria especially bifidobacteria may result in the design of other, new, or novel prebiotics. Thus this review will provide the food industry with different criteria that can be important for the development of prebiotics.

Ber e 1, a major allergen from Brazil nuts, is very stable to in vitro peptic digestion. As heat-induced denaturation may affect protein digestibility, the denaturation behaviour of Ber e 1 was investigated. The denaturation temperature of Ber e 1 varies from approximately 80-110 °C, depending on the pH. Upon heating above its denaturation temperature at pH 7.0, the protein partly forms insoluble aggregates and partly dissociates into its polypeptides, whereas heating at pH 5.0 does neither induce aggregation, nor dissociation of the protein. The denaturation temperature of approximately 110 °C at pH values corresponding to the general pH values of foods (pH 5-7) is very high and is expected to be even higher in Brazil nuts themselves. As a result, it is unlikely that heat processing causes the denaturation of all Ber e 1 present in food products. Consequently, the allergen is assumed to be consumed (mainly) in its native form, having a high stability towards pepsin digestion. © 2008 Elsevier Ltd. All rights reserved.

Given the current robust forces driving sustainable production, and available biomass conversion technologies, biomass-based routes are expected to make a significant impact on the production of bulk chemicals within 10 years, and a huge impact within 20–30 years. In the Port of Rotterdam there is a clear short-term (0–10 year) substitution potential of 10–15 % of fossil oil-based bulk chemicals by bio-based bulk chemicals, especially for oxygenated bulk chemicals, such as ethylene glycol and propylene glycol, iso-propanol and acetone, butylene and methylethylketone and for the replacement of methyl tertiary butyl ether (MTBE) by ethyl tertiary butyl ether (ETBE). Glycerin, as a byproduct of biodiesel production, is a very favorable short-term option for the production of ethylene and propy-lene glycols in the Port of Rotterdam. In the mid-term (10–20 years) there is clear potential for a bio-based production of ethylene, acrylic acid and N-containing bulk chemicals such as acrylonitrile, acrylamide and e-caprolactam. Technologies involving direct isolation of aromatic building blocks from biomass, or the conversion of sugars or lignin to aromatics are still in their infancy. Biorefineries that are being started up today will form the stepping stones toward the chemicals mentioned above if we learn to upgrade their side streams. For main ports like the Port of Rotterdam, these developments imply that it has to consider in much closer detail those facilities it has to offer for a more bio-based chemistry and economy. © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd

Covalent attachment of proteins to carbohydrates can significantly change the functional properties of the polymers, which may be useful industrially. To produce novel functional polymers,for food applications, we explored the enzymatic crosslinking of proteins and polysaccharides. Heterologous conjugates of wheat arabinoxylan and alpha-lactalbumin were prepared by peroxidase-mediated cross-linking, using sequential addition of the arabinoxylan to the mixture of alpha-lactalbumin, peroxidase and hydrogen peroxide. Formation of reaction products was followed by size exclusion chromatography. The protein-arabinoxylan conjugates were separated by anion exchange chromatography and characterized by infrared spectroscopy. The viscosity and emulsifying properties of the novel polymers were measured.

The enzymatic hydrolysis of starch is usually carried out with 30–35 w/w% starch in water. Higher substrate concentrations (50–70 w/w%) were reached by using a twin-screw extruder for gelatinisation and for mixing enzyme with gelatinised starch prior to enzymatic hydrolysis in a batch reactor. The aim of this study was to determine which parameters are important for gelatinisation of wheat starch and to investigate the effects of different extrusion conditions on the enzymatic hydrolysis. After extrusion, the degree of gelatinisation was measured. During hydrolysis, the carbohydrate composition, the dextrose equivalent (DE) and the alpha-amylase activity were measured. Gelatinisation measurements showed that mechanical forces lowered the temperature required for complete gelatinisation. During hydrolysis experiments, high DEs were observed even if starch was not completely gelatinised during extrusion. Due to high substrate concentrations, the residual alpha-amylase activity remained high throughout enzymatic hydrolysis, although high temperatures were used. Increased substrate concentrations did not affect the carbohydrate composition of the product. Furthermore, the time required for the batch hydrolysis step could be varied by choosing a different enzyme-to-substrate ratio. This article provides a basis for detailed optimisation of this process to develop an industrial-scale process at high substrate concentrations.

International audience; The changes in starch properties due to etherification with allyl glycidyl ether (AGE) have been investigated. After etherification of three different starches (containing 0.9%, 27% and 70% amylose), no appreciable differences in granular appearance were observed, but the granule crystallinity of these starches was changed. Furthermore, the incorporation of AGE in the starch significantly affects its physicochemical properties: the gelatinization temperatures were decreased and the pasting properties were altered. Both the swelling power and the solubility index increased as the degree of substitution (DS) increased. The rheology behaviour of the droplets of swollen granules suspension was studied under shear flow conditions

In this study the oxidative polymerization of different lignins, i.e. Flax Soda lignin, Spruce EMAL, and Eucalyptus Dioxane lignin by Trametes hirsuta laccase was compared. Initially the structures of the different lignins were compared by Fourier transform infrared spectroscopy. The reactivity of laccase with the different types of lignins in the absence of mediators was examined and verified by oxygen consumption measurements. The molecular weight distributions of treated and untreated lignins were determined by two different size exclusion chromatography methods. Furthermore, the potential of matrix-assisted laser desorption/ionisation-time of flight-mass spectroscopy for determination of the absolute molecular weights of the different lignins was evaluated. The data showed that all the technical lignins could be activated and polymerized by laccase to different degrees. The efficiency as indicated by measurements of the degree of polymerization was found to increase in the order of Spruce EMAL

A biomass pretreatment process is being developed based on contacting ligno-cellulosic biomass with 70% sulphuric acid and subsequent hydrolysis by adding water. In this process, the hydrolysate can be fermented yielding ethanol, while the sulphuric acid is partly recovered by anion-selective membranes before the fermentation process, and partly via biological sulphate reduction in the anaerobic wastewater treatment plant. The produced sulphide is recovered as H2S gas and chemically converted (burned) into SO 2 and SO3 (by which heat is recovered as well) and subsequently into sulphuric acid. In this unique approach, the sulphuric acid is recycled to a large extent. This process, the Biosulfurol process, is able to handle a wide variety of ligno-cellulosic biomass and does not need the addition of enzymes. In the project switchgrass, willow wood and bagasse are tested as model substrates. The utilization of bagasse can be of interest for the sugar industry and the production of monosaccharides can be regarded as an alternative way to produce sugars from sugarcane residues.

The biomass-based monomer isosorbide was incorporated into poly(butylene terephthalate) (PBT) by solid-state polymerization (SSP) using the macrodiol monomer BTITB-(OH)2, which consists of isosorbide (I), terephthalic acid (T), and 1,4-butandiol (B) residues. This macromonomer can be synthesized by a simple one-pot, two-step reaction. Polymers with number-average molecular weights up to 100 000 g·mol-1 were readily synthesized from various ratios of PBT/BTITB-(OH)2. Their molecular weights, thermal properties, and colors were compared with corresponding copolyesters that were obtained by melt polycondensation. We found that Tm, Tc and especially Tg were superior for materials that were obtained by SSP. This is ascribed to differences in the microstructures of both types of copolyesters; the SSP products exhibit a more blocky structure than do the more random melt- polymerized counterparts. The SSP method resulted in much higher molecular weights and much less colored polymers, and it seems to be the preferred route for incorporating biobased monomers that exhibit limited thermal stability into engineering plastics. © 2008 American Chemical Society

The reactivity and physicochemical properties of lignins are partly governed by their molar mass distribution. The development of reliable standard methods for determination of the molar mass distribution is not only relevant for designing technical lignins for specific applications, but also for monitoring and elucidating delignification and pulping processes. Size-exclusion chromatography (SEC) offers many advantages, such as wide availability, short analysis time, low sample demand, and determination of molar mass distribution over a wide range. A collaborative study has been undertaken within the “Eurolignin” European thematic network to standardise SEC analysis of technical lignins. The high-molar-mass fraction of polydisperse lignins was shown to be the main source of intra- and interlaboratory variations, depending on the gel type, elution solvent, detection mode, and calculation strategy. The reliability of two widespread systems have been tested: one based on alkali and a hydrophilic gel (e.g., TSK Toyopearl gel) and the other based on THF as solvent and polystyrene-based gels (e.g., Styragel). A set of practical recommendations has been deduced.

Polyunsaturated fatty acid (PUFA) rich micro-algal oil was tested in vitro and compared with fish oil for antiproliferative properties on cancer cells in vitro. Oils derived from Crypthecodinium cohnii, Schizochytrium sp. and Nitzschia laevis, three commercial algal oil capsules, and menhaden fish oil were used in cell viability and proliferation tests with human colon adenocarcinoma Caco-2 cells. With these tests no difference was found between algal oil and fish oil. The nonhydrolysed algal oils and fish oil showed a much lower toxic effect on cell viability, and cell proliferation in Caco-2 cells than the hydrolysed oils and the free fatty acids (FFAs). Eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3) were used as samples for comparison with the tested hydrolysed and nonhydrolysed oils. The hydrolysed samples showed comparative toxicity as the free fatty acids and no difference between algal and fish oil. Oxidative stress was shown to play a role in the antiproliferative properties of EPA and DHA, as alpha-tocopherol could partially reverse the EPA/DHA-induced effects. The results of the present study support a similar mode of action of algal oil and fish oil on cancer cells in vitro, in spite of their different PUFA content.

A general procedure was developed to measure the degree of gelatinisation in samples over a broad concentration range. Measurements based on birefringence, DSC (Differential scanning calorimetry), X-ray and amylose–iodine complex formation were used. If a 10 w/w % wheat starch–water mixture was used, each method resulted in approximately the same degree of gelatinisation vs. temperature curve. In case the gelatinisation of a 60 w/w % wheat starch–water mixture was followed as a function of the temperature, each method resulted in a different degree of gelatinisation vs. temperature curve. DSC and X-ray measurements are preferred, because they can be used to determine when the final stage of the gelatinisation process has been completed. Birefringence and amylose–iodine complex formation measurements are suitable alternatives if DSC and X-ray equipment is not available, but will lead to different results. The differences between the methods can be explained by considering the phenomena that take place during the gelatinisation at limiting water conditions. Based on the experimental data obtained with DSC and X-ray measurements, the gelatinisation of 10 w/w % and 60 w/w % wheat starch–water mixtures started at the same temperature (approximately 50 °C). However, complete gelatinisation was reached at different temperatures (approximately 75 °C and 115 °C for, respectively, 10 w/w % and 60 w/w % wheat starch–water mixtures) according to the experimental DSC and X-ray data. These results are in accordance with independent DSC measurements that were carried out. The Flory equation was adapted to provide a quantitative explanation for the curves describing the degree of starch gelatinisation as a function of the starch–water ratio and the temperature. The gelatinisation curves that were obtained with the model are in good agreement with the experimentally determined curves. The parameters T m 0 , ΔHu and χ12 that resulted in the lowest sum of the squared residuals are 291 ± 63 °C, 29.2 ± 3.9 kJ/mol and 0.53 ± 0.05 (95% confidence interval). These values agree with other values reported in literature.

Wasserstoff wird aufgrund seines emissionsarmen Oxidationsprozesses als einer der moglichen Energietrager der Zukunft angesehen. Um eine nachhaltige Wirkung auf den Treibhauseffekt zu erzielen, muss aber auch der Energiebedarf des Produktionsprozesses moglichst gering gehalten werden. Das integrierte Projekt Hyvolution, das im 6. Forschungsrahmenprogramm unter dem Schwerpunkt nachhaltiger Energiesysteme der Europaischen Komission gefordert wird, hat es sich deshalb zum Ziel gemacht, einen zweistufigen Bioprozess zu entwickeln, der zukunftig in dezentralen Kleinanlagen Wasserstoff aus Biomasse freisetzt.

Adhered spores of Bacillus cereus represent a significant part of the surface-derived contamination in processing equipment used in the dairy industry. As germinated spores lose their resistance capacities instantaneously, efficient germination prior to a cleaning in place treatment could aid to the disinfecting effect of such a treatment. Therefore, spores of B. cereus ATCC 14579 and that of the environmental isolate B. cereus CMCC 3328 were assessed for their germination behaviour when adhered to a stainless steel surface. A mixture of l-alanine and inosine initiated germination of adhered spores efficiently, resulting in 3.2 decimal logarithms of germination. Notably, implementation of a germination-inducing step prior to a representative cleaning in place procedure reduced the number of survivors with over 3 decimal log units, while an alkali treatment alone, as part of the cleaning in place procedure, did not show any effect on B. cereus spore viability. These results show that implementation of a germination step enhances the disinfection effect of currently used cleaning in place procedures.

Recently, iron 2-ethylhexanoate (Fe-eh, 1) in combination with ascorbic acid 6-palmitate (AsA6p) has been reported as a good catalytic system for the oxidation of ethyl linoleate (EL), an unsaturated lipid. In response to the fascinating chemistry of this bio-inspired iron-based catalyst the structure of Fe-eh, and the effect of AsA6p on it, have been studied. Fe-eh was found to be a trinuclear oxido-centered iron(III) cluster of general formula . The Mössbauer spectra of 1 indicate that the trinuclear iron core is not symmetric as the spectra exhibit two equivalent iron(III) sites and one unique iron(III) site. Variable temperature magnetic measurements indicate that the three iron centers are antiferromagnetically coupled. Upon the addition of AsA6p to complex 1 a new species (2), which has not yet been completely identified, is formed. Mössbauer spectroscopy indicates, however, that 2 is a mixed-valence cluster which probably has an iron-core that differs in symmetry from 1. The reduction of 1 to 2 was also monitored in time by electrospray ionization mass spectrometry, revealing that the reduction reaction is kinetically dependent on the molar ratio AsA6p/Fe-eh. Based on these results and other available information, a general mechanism for the oxidation of EL under the effect of the combination of AsA6p/Fe-eh is proposed

This paper describes several examples of knowledge-intensive technologies for the production of chemicals from biomass, which take advantage of the biomass structure in a more efficient way than the production of fuels or electricity alone. The depletion in fossil feedstocks, increasing oil prices, and the ecological problems associated with CO(2) emissions are forcing the development of alternative resources for energy, transport fuels, and chemicals, such as the replacement of fossil resources with CO(2) neutral biomass. Allied with this is the conversion of crude oil products utilizes primary products (ethylene, etc.) and their conversion into either materials or (functional) chemicals with the aid of co-reagents such as ammonia, by various process steps to introduce functionalities such as -NH(2) into the simple structures of the primary products. Conversely, many products found in biomass often contain functionalities. Therefore, it is attractive to exploit this in order to by-pass the use, and preparation of, co-reagents as well as to eliminate various process steps by utilizing suitable biomass-based precursors for the production of chemicals.

The goal of this booklet is to raise awareness of the concept of artificial photosynthesis and its potential to become an additional and significant new option in our longer-term energy future.

The goal of this booklet is to raise awareness of the concept of artificial photosynthesis and its potential to become an additional and significant new option in our longer-term energy future.

The effect of hemicellulose and lignin solubilisation by H2SO4 and NaOH catalysed pretreatments was correlated to the extent of subsequent enzymatic cellulose hydrolysis. Three different grass-type feedstocks, palm empty fruit bunch, sugarcane bagasse and barley straw, were investigated. Soluble fractions after catalysis were characterised for mono- and oligosaccharides contents, while the residues were analysed for constituent monosaccharides composition. Alkali pretreatment resulted into extensive lignin removal. This removal resulted in up to 90% (w/w) conversion of glucan into glucose by enzymes. But, the alkaline conditions also provoked up to 50% unwanted xylan losses. Acid pretreatment resulted into solubilisation (70–80% (w/w)) of xylan with almost no losses, while lignin remained. Although moderate xylan solubilisation increased enzymatic cellulose hydrolysis of residual glucan, extensive removal of xylan decreased it. Therefore, under the treatment conditions, the alkali treatments were the most efficient in terms of enzymatic release of xylose and glucose from the insoluble residues.

The aim of this research was to develop practical applicable models capable to describe and to predict the temperature dependent firmness and moisture loss of tomatoes during storage. To gather the required information to develop these models batches of 20 tomatoes (cv. Tradiro), each harvested at two maturity stages, were stored at four different temperatures (3, 12, 20 and 25 °C) up to four weeks. One temperature (3 °C) is known to cause chilling injury to the product. During storage at these temperatures firmness loss, moisture loss and near infrared spectra were measured on individual tomatoes at regular intervals. The decrease in firmness was measured non-destructively by flat-plate compression, moisture loss was measured by weight loss. The information on firmness and moisture loss was used to develop two types of models. The first type of model was based on fundamental laws of chemical kinetics, assuming plausible chemical reaction mechanisms. These reaction mechanisms describe the processes underlying either firmness, or moisture loss. From these reaction mechanisms a set of differential equations was derived and solved at constant temperature. For these kinetic models, both for firmness, and moisture loss, two independent processes were assumed. One process is mainly expressed at low (

A high-molecular-mass polysaccharide galactan (M 2000 kDa) was isolated from flax at the stage of cell wall thickening of the bast fiber development. The polymer structure was studied by 1H NMR spectroscopy and MALDI TOF mass spectrometry. It is built up of Gal (59%), Rha (15%), GalA (23%), and Ara (3%) residues. The galactan backbone consists of successively alternating monomer disaccharide units (- 4GalA1 - 2Rha1 -)n and is similar in its structure to the backbone of rhamnogalacturonan-1 (RG-I). Rhamnose residues bear in position 4 ß-(1 - 4)-galactose side chains of various lengths with a polymerization degree of up to 28 or higher. A part of the side chains have branchings.

Strawberry (Fragaria × ananassa Duch.) fruit softening during ripening is associated with the overlapping presence of two divergent endo-β-(1,4)-glucanases (EC 3.2.1.4; EGases), Cel1 and Cel2. Antisense down-regulation of both genes was performed to assess the precise role of these endo-β-(1,4)-glucanases on strawberry fruit softening. Constant down-regulation of cel1 expression throughout ripening was obtained, which was accompanied by reduced Cel1 protein accumulation. However, diminution of the Cel1 protein level together with a reduction of the total EGase activity to 40% of the control level did not affect fruit firmness, thus suggesting that Cel1 protein is not the major determinant of fruit softening during ripening. On the other hand, no significant reduction of Cel2 protein accumulation was found in any of the Cel2 transgenic or Cel1/Cel2 double-transgenic lines obtained. The difficulties encountered to yield a strawberry line with significant reduction of cel2 expression suggest that this gene might be playing a pivotal role on fruit development prior to ripening, thus accounting for the lack of Cel2 protein down-regulation observed.

For production of compression moulded boards from whole coconut husk the auto-adhesive properties are derived from the intrinsic high lignin content. Since the properties of manufactured boards for a large part will depend on the input husk material these properties are studied here. Husks of different varieties and maturity have been investigated for their contents of fibre and pith. Relevant physical properties and chemical composition were determined. For accurate determination of tensile strength and stiffness of coir fibre, its density (¿coir = 1.2¿1.3 g/cm3) and cross-sectional area were determined. Both thickness and longitudinal swelling of the fibre were measured to assess the effects of water absorption. The constituent fibre and pith fractions of coconut husk have been chemically analysed for polysaccharide (cellulose, pectin and hemicellulose) and lignin contents. Detailed carbohydrate analysis of the fibre indicated a glucose (cellulose) content of approximately 33% in the cell wall, together with 12% xylose as the major component of the hemicellulose fraction. Coir pith only contains 16% glucose. The effects of maturing on the chemical composition of the husk is analysed and a significant increase in glucose (cellulose) is observed, while for other sugars no dramatic change in relative amounts can be measured. It was concluded that only slight differences can be observed between mature coconut husks of different origin, and all are suitable as input feedstock for boards production. More effects can be expected from the age of the nuts.

Fungal alpha-amylase is a flour supplement which is added to improve the quality of bakery products. Various studies have shown that exposure to this enzyme is an important risk factor for the development of bakers' allergy and this allergy is reported to be one of the most frequent causes of occupational asthma. A rapid assay was developed to monitor exposure to occupational allergens directly at the workplace. The sensitivity of the developed assay is 0.32 ng amylase mL(-1) in a buffer system with the commercially available alpha-amylase preparation Fungamyl 1600S as the standard. Initial validation tests (n = 33) were performed with airborne and settled dust from an industrial bakery. The new lateral flow immunoassay detected amylase in 22 of the 26 samples regarded as positive in an enzyme immunoassay, and was negative for all seven enzyme immunoassay-negative samples, while the four lateral flow immunoassay-negative/enzyme immunoassay-positive samples all had levels below 2 ng mL(-1). The sensitivity of 2 ng mL(-1) of the amylase lateral flow immunoassay is sufficient for first screening purposes and, therefore, this simple and rapid assay may allow direct on-site demonstration of work-related hazards of bio-allergen exposure. This would be particularly useful in occupational hygiene practice, especially in traditional or small-scale bakeries which lack the technological skills for testing the exposure to respiratory allergens.

HYVOLUTION is the acronym of an Integrated Project ¿Non-thermal production of pure hydrogen from biomass¿ which has been granted in the Sixth EU Framework Programme on Research, Technological Development and Demonstration, Priority 6.1.ii, Sustainable Energy Systems. The aim of HYVOLUTION: ¿Development of a blue-print for an industrial bioprocess for decentral hydrogen production from locally produced biomass¿ adds to the number and diversity of H2 production routes giving greater security of supply at the local and regional level. Moreover, this IP contributes a complementary strategy to fulfil the increased demand for renewable hydrogen expected in the transition to the Hydrogen Economy. The novel approach in HYVOLUTION is based on a combined bioprocess employing thermophilic and phototrophic bacteria, to provide the highest hydrogen production efficiency in small-scale, cost-effective industries. In HYVOLUTION, 11 EU countries, Turkey and Russia are represented to assemble the critical mass needed to make a breakthrough in cost-effectiveness.

Results of a round robin on lignin thermal analyses are reported. Six laboratories have conducted thermal analyses of four lignin types to determine their cp values and softening points, and to study the thermal behaviour, materials endo- and exotherms included. The lignin types examined were wood Kraft lignin, steam explosion lignin, bagasse lignin, and lignosulfonates. Thermal analyses were carried out over the 20-900°C temperature range, at a heating rate of 10 °C/min, under both inert (nitrogen) and oxidative (air/oxygen) atmosphere. Six different types of thermal analyzers (DSC and TG equipment) were tested. A lignin chemical reactivity test was also considered. Several laboratories identified similar lignin softening temperatures for some of the samples, yet, generally, the results attained are characterised by a high variability of the lignin types and analytical protocols applied in the six laboratories. The different results have been mainly attributed to the "history" of the material, e.g., whether the samples were completely dried before the experiments

The paper discusses the results of a round robin experiment initiated by the participants to "EUROLIGNIN", an EC network, meant at standardizing thermogravimetry as an useful method for the thermal characterization of lignins obtained from different sources or by different extraction methods. Five laboratories from five countries took part in the experiment, the reached conclusion being that thermogravimetry is a suitable method for the determination of the moisture and ash content, thermal and thermo-oxidative stability, and also that DTG curves should be regarded as thermal spectra for lignin identification.

Tomatoes (cv. Tradiro), harvested at two maturity stages, were stored at four different temperatures during up to four weeks. The lowest storage temperature was known to cause chilling injury, the three other temperatures were regarded save. During storage Near Infrared spectra of intact tomatoes were recorded and samples were taken at regular time intervals to determine the activities of the pectolytic enzymes polygalacturonase, pectin methyl esterase and β-galactosidase. The maturity stage of the tomatoes at harvest, followed by storage at the four different temperatures affects the activities of these enzymes. To describe the change in activity of these enzymes kinetic models were built based on fundamental laws of chemical kinetics using assumed, but plausible reaction mechanisms. For the models developed, a fixed and a variable enzyme activity were observed for these three enzymes. For polygalacturonase, this fixed amount of enzyme activity was dependent on maturity stage at harvest. For pectin methyl esterase and β-galactosidase the maturity at harvest had almost no effect on this fixed amount of enzyme activity. The variable part of the enzyme activity could either increase in time (polygalacturonase), followed by denaturation (β-galactosidase), or only decay in time (pectin methyl esterase). For the activity of polygalacturonase, a self-initiated, autocatalytic production of this enzyme was assumed. β-Galactosidase was formed, but inactivated in time. Pectin methyl esterase activity decayed exponentially in time. The models for polygalacturonase and β-galactosidase were integrated into the previously developed model for the firmness loss of tomatoes during storage [Van Dijk, C., Boeriu, C., Peter, F., Stolle-Smits, T., & Tijskens, L. M. M. (2005). The firmness of stored tomatoes (cv. Tradiro). 1. Kinetic and Near Infrared models to describe firmness and moisture loss. Journal of Food Engineering, in press]. It was concluded that any cell wall degrading enzyme, which activity remains within a certain bandwidth, can be integrated into the firmness model to explain the observed firmness decay. Based on Near Infrared spectroscopy, a statistical significant relation was only observed between the polygalacturonase activity and the Near Infrared spectra of intact tomatoes. It is argued that the consequences of the performed polygalacturonase activity are reflected in this relation rather than the amount of this enzyme. Since mutual statistical significant relations exist between Near Infrared spectra, polygalacturonase activity and the tomato firmness it seems reasonable to ascribe a significant role of this enzyme to the firmness decay.

Workplace-related allergen exposure is an important risk factor for the development of occupational allergy and asthma. New allergen specific semi-quantitative tests, Lateral Flow Immuno Assays (LFIAs), have been developed for the detection of occupational allergen exposure directly at the workplaces. These tests are quick and simple to perform, the results are visible within minutes and easily interpretable. In this article, the principle of LFIA is described and the practical application of the immunoassays for mouse and rat urinary allergens in a laboratory animal facility is presented. The results show that the sensitivity of the rapid tests is sufficient for the detection of small amounts of allergen in extracts from deposited dust. Thus they can help to reveal the allergen sources and to develop preventive and interventional measures. Furthermore, the LFIAs are especially suited for the direct on-site demonstration of allergen contaminations to staff members and, therefore, useful in occupational hygiene practice. This method is also a feasible screening system before starting extensive measurements of airborne allergens.