Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    Improving the feeding value of straws with Pleurotus ostreatus
    Khan, N.A. ; Hussain, S. ; Ahmad, N. ; Alam, S. ; Bezabhi, M. ; Hendriks, W.H. ; Yu, P. ; Cone, J.W. - \ 2015
    Animal Production Science 55 (2015)2. - ISSN 1836-0939 - p. 241 - 245.
    chemical-composition - wheat-straw - digestibility - fermentation - diets - fiber
    The high content of lignin in cell walls is the major limiting factor in the digestion and utilisation of cereal crop residues by ruminants. The aim of this study was to evaluate the effectiveness of the white rot fungus, Pleurotus ostreatus (P. ostreatus), to degrade lignin and to enhance the rumen degradability of maize stover, rice straw, wheat straw and their mixture in equal proportion on a dry-matter (DM) basis. Four samples of each substrate were incubated aerobically in triplicate with P. ostreatus for 0 (Control), 21, 28 and 35 days under solid-state conditions (temperature, 24°C; humidity, 70 ± 5%). The changes in chemical composition, DM and nutrient losses, and rumen fermentation characteristics using in vitro DM digestibility (DMD) and the in vitro gas-production (GP) technique were measured. The results showed that incubation with P. ostreatus decreased (P <0.001) the contents of neutral detergent fibre and lignin with a concomitant increase (P <0.001) in the contents of ash and crude protein. The losses of nutrients differed (P <0.001) among the straw types, with rice straw and maize stover showing the largest (P <0.05) lignin degradation compared to wheat and mixed straws. The DMD and 72-h cumulative GP increased (P <0.001) consistently with increasing fungal incubation period and for all substrates the highest values of DMD and GP were measured after 35 days of incubation with P. ostreatus. The lignin degradation was strongly associated with hemicellulose degradation (r = 0.71) across the various straws. Results of the present study demonstrated that incubation of low-quality crop residues with P. ostreatus under solid-state conditions upgrades their feeding value by reducing the content of lignin and increasing the content of crude protein and ruminal degradation.
    Side by Side Comparison of Chemical Compounds Generated by Aqueous Pretreatments of Maize Stover, Miscanthus and Sugarcane Bagasse
    Gomez, L.D. ; Vanholme, R. ; Bird, S. ; Goeminne, G. ; Trindade, L.M. ; Polikarpov, I. ; Simister, R. ; Morreel, K. ; Boerjan, W. ; McQueen-Mason, S.J. - \ 2014
    Bio Energy Research 7 (2014)4. - ISSN 1939-1234 - p. 1466 - 1480.
    cell-walls - bioethanol production - ferulic acid - wheat-straw - energy crop - lignin - saccharification - ethanol - delignification - technologies
    In order to examine the potential for coproduct generation, we have characterised chemical compounds released by a range of alkaline and acidic aqueous pretreatments as well as the effect of these pretreatments on the saccharification ability of the lignocellulosic material. Comparative experiments were performed using three biomass types chosen for their potential as second-generation biofuel feedstocks: maize stover, miscanthus and sugarcane bagasse. The release of lignin from the feedstock correlated with the residual biomass saccharification potential, which was consistently higher after alkaline pretreament for all three feedstock types. Alkaline pretreatment released more complex mixtures of pentose and hexose sugars into the pretreatment liquor than did acid pretreatment. In addition, complex mixtures of aromatic and aliphatic compounds were released into pretreatment liquors under alkaline conditions, in a temperature-dependent manner, but far less so under acidic conditions. We show that the three feedstocks characterised interact with the pretreatment conditions in a specific manner to generate different ranges of products, highlighting the need to tailor pretreatments to both the starting feedstock and desired outcomes.
    Lignin pyrolysis for profitable lignocellulosic biorefineries
    Wild, P.J. de; Gosselink, R.J.A. ; Huijgen, W.J.J. - \ 2014
    Biofuels Bioproducts and Biorefining 8 (2014)5. - ISSN 1932-104X - p. 645 - 657.
    wheat-straw - organosolv lignin - biomass - phenols - separation - valorization - pretreatment - hydrolysis - conversion - chemicals
    Bio-based industries (pulp and paper and biorefineries) produce > 50 Mt/yr of lignin that results from fractionation of lignocellulosic biomass. Lignin is world's second biopolymer and a major potential source for production of performance materials and aromatic chemicals. Lignin valorization is a key-issue for enhanced profitability of sustainable bio-based industries. Despite a myriad of potential applications for lignin and decades of research, its heterogeneity and recalcitrance still preclude commercial value-added applications. Most lignin is utilized for heat and power. Unconventional solutions are needed to better exploit lignin's potential. Organosolv lignins are especially suitable as feedstock for high-value chemicals. At ECN, a lignin biorefinery approach (LIBRA) has been developed, involving a dedicated lignin pyrolysis protocol that is robust, continuous, and capable of processing different lignins. Typical product yields are 20% gas, 35% char, and 45% oil. The oil contains approximately 45% oligomeric phenolic substances, 23% monomeric phenols, and 33% water. The future perspective is scale-up of the process to produce larger lignin pyrolysis oil samples for separation, purification, and industrial application tests. Presently, small lignin pyrolysis oil samples are investigated as feedstock for extracting high-value chemicals, as a substitute for phenol in several applications, and as a feedstock for hydrotreating. The biochar is tested as growth enhancer and as substitute for carbon-black in rubber. Regarding the large lignin side streams from (future) bio-based industries, the LIBRA pyrolysis technology has ample potential to increase the profitability of lignocellulosic biorefineries provided that for both the liquid product and the solid char value-added applications are developed.
    By-products resulting from lignocellulose pretreatment and their inhibitory effect on fermentations for (bio)chemicals and fuels
    Pol, E.C. van der; Bakker, R.R. ; Baets, P. ; Eggink, G. - \ 2014
    Applied Microbiology and Biotechnology 98 (2014)23. - ISSN 0175-7598 - p. 9579 - 9593.
    dilute-acid hydrolysis - steam-explosion pretreatment - fiber expansion afex - saccharomyces-cerevisiae - degradation-products - escherichia-coli - ethanol fermentation - wheat-straw - sugarcane bagasse - wet oxidation
    Lignocellulose might become an important feedstock for the future development of the biobased economy. Although up to 75 % of the lignocellulose dry weight consists of sugar, it is present in a polymerized state and cannot be used directly in most fermentation processes for the production of chemicals and fuels. Several methods have been developed to depolymerize the sugars present in lignocellulose, making the sugars available for fermentation. In this review, we describe five different pretreatment methods and their effect on the sugar and non-sugar fraction of lignocellulose. For several pretreatment methods and different types of lignocellulosic biomass, an overview is given of by-products formed. Most unwanted by-products present after pretreatment are dehydrated sugar monomers (furans), degraded lignin polymers (phenols) and small organic acids. Qualitative and quantitative effects of these by-products on fermentation processes have been studied. We conclude this review by giving an overview of techniques and methods to decrease inhibitory effects of unwanted by-products.
    Synergistic action of enzyme preparations towards recalcitrant corn silage polysaccharides
    Neumüller, K.G. ; Streekstra, H. ; Schols, H.A. ; Gruppen, H. - \ 2014
    Biomass and Bioenergy 60 (2014). - ISSN 0961-9534 - p. 88 - 97.
    talaromyces-emersonii - wheat-straw - hydrolysis - pretreatment - ethanol - plant - lignocellulose - fermentation - efficiency - conversion
    Corn silage, its water unextractable solids (WUS) and enzyme recalcitrant solids (ErCS) and an industrial corn silage-based anaerobic fermentation residue (AFR) represent corn substrates with different levels of recalcitrance. Compositional analysis reveals different levels of arabinoxylan substitution for WUS, ErCS and AFR, being most pronounced regarding acetic acid, glucuronic acid- and arabinose content. By screening for enzymatic degradation of WUS, ErCS and AFR, enzyme preparations exhibiting high conversion rates were identified. Furthermore significant synergistic effects were detected by blending Aspergillus niger/Talaromyces emersonii culture filtrates with various enzymes. These findings clearly highlight a necessity for a combinatorial use of enzyme preparations towards substrates with high recalcitrance characteristics to reach high degrees of degradation. Enzyme blends were identified, outperforming the individual commercial preparations. These enzyme preparations provide a basis for new, designed enzyme mixtures for corn polysaccharide degradation as a source of necessary, accessory enzyme activities.
    Carbohydrate utilization and metabolism is highly differentiated in Agaricus bisporus
    Patyshakuliyeva, A. ; Jurak, E. ; Kohler, A. ; Baker, A. ; Battaglia, E. ; Bruijn, W. de; Burton, K.S. ; Challen, M.P. ; Cuotinho, P.M. ; Eastwood, D.C. ; Gruben, B.S. ; Makela, M.R. ; Martin, F. ; Nadal, M. ; Brink, J. van den; Wiebenga, A. ; Zhou, M. ; Henrissat, B. ; Kabel, M.A. ; Gruppen, H. ; Vries, R.P. de - \ 2013
    BMC Genomics 14 (2013). - ISSN 1471-2164 - 14 p.
    cell-wall polysaccharides - aspergillus-niger - wheat-straw - d-galactose - trehalose phosphorylase - mannitol dehydrogenase - sporophore development - enzyme-activities - button mushroom - fruit bodies
    Background - Agaricus bisporus is commercially grown on compost, in which the available carbon sources consist mainly of plant-derived polysaccharides that are built out of various different constituent monosaccharides. The major constituent monosaccharides of these polysaccharides are glucose, xylose, and arabinose, while smaller amounts of galactose, glucuronic acid, rhamnose and mannose are also present. Results - In this study, genes encoding putative enzymes from carbon metabolism were identified and their expression was studied in different growth stages of A. bisporus. We correlated the expression of genes encoding plant and fungal polysaccharide modifying enzymes identified in the A. bisporus genome to the soluble carbohydrates and the composition of mycelium grown compost, casing layer and fruiting bodies. Conclusions - The compost grown vegetative mycelium of A. bisporus consumes a wide variety of monosaccharides. However, in fruiting bodies only hexose catabolism occurs, and no accumulation of other sugars was observed. This suggests that only hexoses or their conversion products are transported from the vegetative mycelium to the fruiting body, while the other sugars likely provide energy for growth and maintenance of the vegetative mycelium. Clear correlations were found between expression of the genes and composition of carbohydrates. Genes encoding plant cell wall polysaccharide degrading enzymes were mainly expressed in compost-grown mycelium, and largely absent in fruiting bodies. In contrast, genes encoding fungal cell wall polysaccharide modifying enzymes were expressed in both fruiting bodies and vegetative mycelium, but different gene sets were expressed in these samples
    Effect of fungal treatments of fibrous agricultural by-products on chemical composition and in vitro rumen fermentation and methane production
    Tuyen, D.V. ; Phuong, H.N. ; Cone, J.W. ; Baars, J.J.P. ; Sonnenberg, A.S.M. ; Hendriks, W.H. - \ 2013
    Bioresource Technology 129 (2013). - ISSN 0960-8524 - p. 256 - 263.
    white-rot fungi - wheat-straw - rice straw - invitro digestibility - pleurotus-ostreatus - digestion kinetics - sugarcane bagasse - detergent fiber - animal feed - lignin
    Maize stover, rice straw, oil palm fronds and sugarcane bagasse were treated with the white-rot fungi Ceriporiopsis subvermispora, Lentinula edodes, Pleurotus eryngii, or Pleurotus ostreatus at 24 °C for 0–6 weeks. The fungi increased total gas production from oil palm fronds by 68–132%, but none of the fungi improved the in vitro rumen fermentability of maize stover. C. subvermispora and L. edodes increased total gas production of sugarcane bagasse by 65–71%, but P. eryngii and P. ostreatus decreased it by 22–50%. There was a linear relationship (P <0.05) between the proportion of lignin in the original substrate and the increase in in vitro gas production observed for C. subvermispora and L. edodes treatments (R2 = 0.92 and 0.96, respectively). It is concluded that C. subvermispora and L. edodes have a particularly high potential to improve the nutritive value of highly lignified ruminant feeds.
    Dilute-acid pretreatment of barley straw for biological hydrogen production using Caldicellulosiruptor saccharolyticus
    Panagiotopoulos, I.A. ; Bakker, R.R.C. ; Vrije, G.J. de; Claassen, P.A.M. ; Koukios, E.G. - \ 2012
    International Journal of Hydrogen Energy 37 (2012)16. - ISSN 0360-3199 - p. 11727 - 11734.
    thermotoga-neapolitana - extreme thermophiles - inhibitory compounds - wheat-straw - biomass - fermentation - hydrolysis - severity - microflora - conversion
    The main objective of this study was to use the fermentability test to investigate the feasibility of applying various dilute acids in the pretreatment of barley straw for biological hydrogen production. At a fixed acid loading of 1% (w/w dry matter) 28-32% of barley straw was converted to soluble monomeric sugars, while at a fixed combined severity of -0.8 30 -32% of the straw was converted to soluble monomeric sugars. With fermentability tests at sugar concentrations 10 and 20 g/L the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus showed good hydrogen production on hydrolysates of straw pretreated with H3PO4 and H2SO4, and to a lesser extent, HNO3. The fermentability of the hydrolysate of straw pretreated with HCl was lower compared to the other acids but equally high as that of pure sugars. At sugar concentration 30 g/L the fermentability of all hydrolysates was low.
    Effect of low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis on the production of fermentable substrates and the release of inhibitory compounds
    Panagiotopoulos, I.A. ; Lignos, G.D. ; Bakker, R.R.C. ; Koukios, E.G. - \ 2012
    Journal of Cleaner Production 32 (2012). - ISSN 0959-6526 - p. 45 - 51.
    hydrogen-production - wheat-straw - caldicellulosiruptor-saccharolyticus - saccharomyces-cerevisiae - thermotoga-neapolitana - bioethanol production - sweet sorghum - ionic liquid - corn stover - ethanol
    The objective of this work was to investigate the feasibility of combining low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis for the high production of fermentable substrates and the low release of inhibitory compounds. For most of the pretreatments at 160 and 180 degrees C, the sugar production with 15 FPU (filter paper unit)/g straw was equally high compared to higher enzyme loadings. For the pretreatments at 170 degrees C an enzyme loading higher than 15 FPU/g straw was necessary to achieve a carbohydrate conversion of 50% or higher. The effect of acid loading on sugar production was discernible only in the experiments with 15 FPU/g straw or higher. The concentration of 5-hydroxymethylfurfural (HMF), levulinic acid and formic acid was kept below 0.7, 0.6 and 0.8 g L-1, respectively, with all experiments. The release of acetic acid and furfural reached toxic levels with experiments at 170 degrees C and experiments at 180 degrees C, respectively. Decreasing the enzyme loading did not have a major effect on the release of HMF, furfural and formic acid but resulted in decreased release of acetic acid and levulinic acid at 170 and 180 degrees
    DNA marking of some quantitative trait loci in the cultivated edible mushroom Pleurotus ostreatus (Fr.) Kumm
    Sivolapova, A.B. ; Shnyreva, A.V. ; Sonnenberg, A.S.M. ; Baars, J.J.P. - \ 2012
    Russian Journal of Genetics 48 (2012)4. - ISSN 1022-7954 - p. 383 - 389.
    wheat-straw - effluent
    Fungi of the genus Pleurotus, in particular, species Pleurotus ostreatus (common oyster mushroom) are among most cultivated fungi in the world. Due to intense rates of development of studies in this field, efficient breeding programs are highly required in the search for new P. ostreatus strains. The principal traits used worldwide for selecting strains are intensity of fruitbearing, fruit body cap color (for some consumptive markets), and mycelium growth rate. In this connection, the objective of this work was to study these quantitative traits and to find molecular markers, which could be employed to accomplish breeding programs. In general, we found 12 genomic loci (quantitative trait loci, QTLs) controlling mycelium growth rate of oyster and six QTLs responsible for the fruit body cap color. The genetic map of P. ostreatus was constructed, and all markers of quantitative traits found by us were located on this genetic map. The obtained linkage map can be a useful tool for the accomplishment of breeding programs to improve economically important traits of oyster mushroom.
    Rumen degradation of oil palm fronds is improved through pre-digestion with white rot fungi but not through supplementation with yeast or enzymes
    Hassim, H.A. ; Lourenco, M. ; Goh, Y.M. ; Baars, J.J.P. ; Fievez, V. - \ 2012
    Canadian Journal of Animal Science 92 (2012)1. - ISSN 0008-3984 - p. 79 - 87.
    vitro fermentation characteristics - in-vitro - rice straw - chemical-composition - fibrolytic enzymes - wheat-straw - metabolism - degradability - digestibility - culture
    Rumen fermentation kinetics of oil palm fronds (OPF) supplemented or not with enzymes (Hemicell® or Allzyme SSF®) or yeasts (Levucell®SC or Yea-Sacc®) were studied through an in vitro gas production test (96 h) (exp. 1). In exp. 2, enzymes were supplemented to OPF pre-treated during 3 or 9 wk with either one of five white rot fungi strains. Yeasts and enzymes were tested both in active and inactive forms, which revealed the most appropriate set-up to distinguish between the rate of supplements as direct contributors to the fermentation substrate vs. stimulators of the fermentation of the basal substrate. In exp 1, addition of active and inactive Yea-Sacc® increased the apparently rumen degradable carbohydrates (ARDC) by 11%, whereas enzymes did not affect rumen degradability of non-inoculated OPF. Neither yeast nor enzymes influenced the rate of gas production of non-inoculated OPF, except for active Hemicell® at the low dose. In exp. 2, inoculation of OPF with Ceriporiopsis subvermispora for 3 wk and Lentinula edodes for 9 wk increased ARDC, but additional enzyme supplementation did not further improve ARDC or the rate of gas production.
    Effect of pretreatment severity on the conversion of barley straw to fermentable substrates and the release of inhibitory compounds
    Panagiotopoulos, I. ; Bakker, R.R. ; Vrije, G.J. de; Koukios, E.G. - \ 2011
    Bioresource Technology 102 (2011)24. - ISSN 0960-8524 - p. 11204 - 11211.
    dilute-acid pretreatment - ethanol-production - saccharomyces-cerevisiae - hydrogen-production - wheat-straw - caldicellulosiruptor-saccharolyticus - enzymatic saccharification - extreme thermophile - corn stover - acetic-acid
    The production of fermentable substrates from barley straw under various process conditions was studied. Pretreatment included chemical pretreatment with dilute-acid followed by enzymatic hydrolysis; the pretreatment conditions were expressed in a combined severity factor, CS, which ranged in the present study from -1.6 to 1.1. Considering the production of fermentable sugars and the release of inhibitory compounds, the optimal pretreatment conditions were 170 °C, 0% sulfuric acid and 60 min, corresponding to CS -0.4. Under these conditions, 21.4 g glucose/L, 8.5 g xylose/L, and 0.5 g arabinose/L were produced, while 0.1 g HMF/L, 0.4 g furfural/L, 0.0 g levulinic acid/L, 0.0 g formic acid/L, and 2.1 g acetic acid/L were released. The ratio of Ssugars/Sinhibitors proved to be a good tool for evaluating the suitability of a hydrolysate for fermentation purposes.
    Improving ruminal degradability of oil palm fronds using white rot fungi
    Rahman, M.M. ; Lourenco, M. ; Hassim, H.A. ; Baars, J.J.P. ; Sonnenberg, A.S.M. ; Cone, J.W. ; Boever, J.L. de; Fievez, V. - \ 2011
    Animal Feed Science and Technology 169 (2011)3-4. - ISSN 0377-8401 - p. 157 - 166.
    in-vitro digestibility - chemical-composition - wheat-straw - cattle feed - substrate - fermentation - lignin - waste - plant
    The use of oil palm fronds (OPF) in livestock production is limited as up to 0.20 of their dry biomass is lignin. White rot fungi (WRF) are very effective basidiomycetes for biological pre-treatment as they degrade lignin extensively. Ten WRF were screened for their potential to increase OPF digestibility, which were colonized with one of the 10 WRF for 3 or 9 wks at 30 °C. After colonization, weight loss, neutral detergent fiber, acid detergent fiber, lignin(pm), cellulose, crude protein and ash were determined. Further, in vitro gas production was determined using rumen fluid either, or not, adapted to OPF. Finally, in vitro degradability of organic matter was determined using cellulase. Results showed that longer colonization was associated with higher dry matter (DM) losses. Phanerochaete chrysosporium had the highest weight loss, whereas OPF colonized for 9 wks with Ceriporiopsis subvermispora, Pleurotus ostreatus, Phlebia brevispora, Lentinula edodes, Pleurotus eryngii and Trametes versicolor had the highest lignin(pm) degradation. Treatments with the highest lignin(pm) loss, rather than selective lignin(pm) degradation, had the most potential to increase in vitro gas or volatile fatty acid production. Nevertheless, total lignin(pm) loss explained only 0.60 of the variation in in vitro DM degradability. It appeared that within the selected group of fungi which had the highest lignin(pm) degradation (i.e., C. subvermispora, Ganoderma lucidum, L. edodes, P. brevispora and P. eryngii), additional cellulose degradation was essential to substantially increase in vitro DM degradability either with rumen fluid adapted, or not, to OPF. C. subvermispora (3 wks) and L. edodes and P. brevispora (9 wks) were most promising for OPF pre-treatment, but relatively high biomass losses during fungi colonization need further research attention.
    The potential of white-rot fungi to degrade phorbol esters of Jatropha curcas L. seed cake
    Barros, C.R.M. de; Ferreira, L.M.M. ; Nunes, F.M. ; Bezerra, R.M.F. ; Dias, A.A. ; Guedes, C. ; Cone, J.W. ; Marques, G.S.M. ; Rodrigues, M.A.M. - \ 2011
    Engineering in Life Sciences 11 (2011)1. - ISSN 1618-0240 - p. 107 - 110.
    chemical-composition - wheat-straw - provenances - diacylglycerols - bioremediation - constituents - mexico - state - water
    The potential of solid-state cultivation, with three white-rot fungi (Bjerkandera adusta, Ganoderma resinaceum and Phlebia rufa), to decrease phorbol esters concentration of Jatropha curcas L. was evaluated in this study. Incubation was conducted in 250¿mL Erlenmeyer flasks without agitation at 28°C for 30 days. Phorbol esters were analyzed by reverse-phase HPLC after an extraction procedure using dichloromethane. All fungi studied were able to decrease the concentration of phorbol esters, mainly B. adusta and P. rufa which significantly reduced (p
    Utilization of rice straw and different treatments to improve its feed value for ruminants: A review
    Sarnklong, C. ; Cone, J.W. ; Pellikaan, W.F. ; Hendriks, W.H. - \ 2010
    Asian-Australasian Journal of Animal Sciences 23 (2010)5. - ISSN 1011-2367 - p. 680 - 692.
    white-rot fungi - vitro fermentation characteristics - alkaline hydrogen-peroxide - 3 cultivation seasons - wheat-straw - chemical-composition - in-vitro - rumen fermentation - fibrolytic enzymes - sodium-hydroxide
    This paper gives an overview of the availability, nutritive quality, and possible strategies to improve the utilization of rice straw as a feed ingredient for ruminants. Approximately 80% of the rice in the world is grown by small-scale farmers in developing countries, including South East Asia. The large amount of rice straw as a by-product of the rice production is mainly used as a source of feed for ruminant livestock. Rice straw is rich in polysaccharides and has a high lignin and silica content, limiting voluntary intake and reducing degradability by ruminal microorganisms. Several methods to improve the utilization of rice straw by ruminants have been investigated in the past. However, some physical treatments are not practical because of the requirement for machinery or treatments are not economical feasible for the farmers. Chemical treatments, such as NaOH, NH3 or urea, currently seem to be more practical for on-farm use. Alternative treatments to improve the nutritive value of rice straw are the use of ligninolytic fungi (white-rot fungi), with their extracellular ligninolytic enzymes, or specific enzymes degrading cellulose and/or hemicellulose. The use of fungi or enzyme treatments is expected to be a more practical and environmental-friendly approach for enhancing the nutritive value of rice straw and can be cost-effective in the future. Using fungi and enzymes might be combined with the more classical chemical or physical treatments. However, available data on using fungi and enzymes for improving the quality of rice straw are relatively scarce.
    Effect of olive mill waste (OMW) supplementation to Oyster mushrooms substrates on the cultivation parameters and fruiting bodies quality
    Ruiz-Rodriguez, A. ; Soler-Rivas, C. ; Polonia, I. ; Wichers, H.J. - \ 2010
    International Biodeterioration and Biodegradation 64 (2010)7. - ISSN 0964-8305 - p. 638 - 645.
    pleurotus-ostreatus - enzyme-activities - wheat-straw - lignocellulosic wastes - edible mushrooms - water - white - edodes - fungi - bioremediation
    Seven Oyster mushroom strains were cultivated in wheat straw (WS) bags supplemented with 0 up to 90% olive mill waste (OMW), a solid residue obtained from a two-phases olive oil production system. All mushroom strains could grow but high OMW concentrations resulted in a significant yield, biological efficiency and productivity decrease, retarding of pinning and flushing and loss of fruiting bodies quality. However, most of the mushroom strains showed no significant differences on cultivation parameters and fruiting bodies quality (except for colour) between control (WS) substrates or substrates supplemented up to 50% OMW (w/w). Addition of 50% OMW to WS substrates turned mushrooms lighter and less reddish. This colour shift was not due to enzymatic oxidations or inhibition since laccase and peroxidase activities were not differing from control. Total phenolic content and antioxidant activity were also similar and no phenolic compounds from OMW were detected in the fruiting bodies. Some of the analysed Pleurotus strains were better suited to grow on OMW supplemented substrates than others.
    Pretreatment of sweet sorghum bagasse for hydrogen production by Caldicellulosiruptor saccharolyticus
    Panagiotopoulos, I.A. ; Bakker, R.R. ; Vrije, G.J. de; Koukios, E.G. ; Claassen, P.A.M. - \ 2010
    International Journal of Hydrogen Energy 35 (2010)15. - ISSN 0360-3199 - p. 7738 - 7747.
    extreme thermophile - thermotoga-elfii - wheat-straw - biomass - saccharification - fermentation - inhibition - miscanthus - sugars
    Pretreatment of sweet sorghum bagasse, an energy crop residue, with NaOH for the production of fermentable substrates, was investigated. Optimal conditions for the alkaline pretreatment of sweet sorghum bagasse were realized at 10% NaOH (w/w dry matter). A delignification of 46% was then observed, and improved significantly the efficiency of enzymatic hydrolysis. Under hydrolysis conditions without pH control, up to 50% and 41% of the cellulose and hemicellulose contained in NaOH-pretreated sweet sorghum bagasse were converted by 24 h enzymatic hydrolysis to soluble monomeric sugars. The extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus showed normal growth on hydrolysates of NaOH-pretreated biomass up to a sugar concentration of 20 g/L. Besides hydrogen, the main metabolic products detected in the fermentations were acetic and lactic acid. The maximal hydrogen yield observed in batch experiments under controlled conditions was 2.6 mol/mol C6 sugar. The maximal volumetric hydrogen production rate ranged from 10.2 to 10.6 mmol/(L h). At higher substrate concentrations the production of lactic acid increased at the expense of hydrogen production.
    Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass
    Fernandes, T. ; Klaasse Bos, G.J. ; Zeeman, G. ; Sanders, J.P.M. ; Lier, J.B. van - \ 2009
    Bioresource Technology 100 (2009)9. - ISSN 0960-8524 - p. 2575 - 2579.
    corn stover - enzymatic-hydrolysis - wheat-straw - technologies - switchgrass - manure - acid
    The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After pre-treatment, the plant material was anaerobically digested in batch bottles under mesophilic conditions for 40 days. From the pre-treatment and subsequent anaerobic digestion experiments, it was concluded that when the lignin content of the plant material is high, thermo-chemical pre-treatments have a positive effect on the biodegradability of the substrate. Calcium hydroxide pre-treatment improves the biodegradability of lignocellulosic biomass, especially for high lignin content substrates, like bracken. Maleic acid generates the highest percentage of dissolved COD during pre-treatment. Ammonium pre-treatment only showed a clear effect on biodegradability for straw.
    Pretreatments to enhance the digestibility of lignocellulosic biomass
    Hendriks, A.T.W.M. ; Zeeman, G. - \ 2009
    Bioresource Technology 100 (2009)1. - ISSN 0960-8524 - p. 10 - 18.
    steam-explosion pretreatment - wet oxidation pretreatment - ethanol-tolerant mutant - yellow-poplar sawdust - liquid hot-water - enzymatic-hydrolysis - clostridium-thermocellum - wheat-straw - corn stover - lime pretreatment
    Lignocellulosic biomass represents a rather unused source for biogas and ethanol production. Many factors, like lignin content, crystallinity of cellulose, and particle size, limit the digestibility of the hemicellulose and cellulose present in the lignocellulosic biomass. Pretreatments have as a goal to improve the digestibility of the lignocellulosic biomass. Each pretreatment has its own effect(s) on the cellulose, hemicellulose and lignin; the three main components of lignocellulosic biomass. This paper reviews the different effect(s) of several pretreatments on the three main parts of the lignocellulosic biomass to improve its digestibility. Steam pretreatment, lime pretreatment, liquid hot water pretreatments and ammonia based pretreatments are concluded to be pretreatments with high potentials. The main effects are dissolving hemicellulose and alteration of lignin structure, providing an improved accessibility of the cellulose for hydrolytic enzymes.
    Effects of Eucalyptus globulus Wood Autohydrolysis Conditions on the Reaction Products
    Garrote, G. ; Kabel, M.A. ; Schols, H.A. ; Falque, E. ; Domingues, H. ; Parajo, J.C. - \ 2007
    Journal of Agricultural and Food Chemistry 55 (2007)22. - ISSN 0021-8561 - p. 9006 - 9013.
    lipophilic extractives - chemical-composition - kinetic assessment - wheat-straw - by-products - oligosaccharides - fractionation - liquors - water - lignocellulosics
    Eucalyptus globulus wood samples were reacted in aqueous media (hydrothermal treatments) at 160 °C for 30¿66 min. Liquors from the several experiments were analyzed by spectrophotometry, high-performance liquid chromatography, or gas chromatography¿mass spectrometry for monosaccharides, oligosaccharides, oligosaccharide substituents (arabinose moieties, uronic acids, and acetyl groups), acetic acid, furfural, hydroxymethylfurfural, and dichloromethane-soluble compounds. Individual components of this latter fraction were identified and quantified. The molecular weight distribution of oligosaccharides was studied by high-performance size exclusion chromatography. The kinetics of xylan conversion into high-, medium-, and low-molecular-weight products was assessed in terms of the severity factor and by pseudohomogeneous kinetic models. Keywords: Autohydrolysis; Eucalyptus globulus; product distribution; xylo-oligosaccharides
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