Sample records for autohydrolysis

  1. Autohydrolysis of phytic acid. (United States)

    Hull, S R; Gray, J S; Montgomery, R


    The autohydrolysis of phytic acid at 120 degrees C resulted in the formation of most of the phosphate esters of myo-inositol in varying amounts depending upon the reaction time. Eighteen of the 39 chromatographically distinct myo-inositol mono-, bis-, tris-, tetrakis-, pentakis-, and hexakisphosphates have been characterized using two different HPLC systems. These myo-inositol phosphates were partially purified by preparative anion-exchange chromatography under acidic and alkaline elution conditions. The combination of these two methods provides a two-tiered chromatographic approach to the rapid and sensitive identification of inositol phosphates in complex mixtures. Identification of the products was confirmed by 1D and 2D (1)H NMR analysis. The analytical procedure was applied to the autohydrolysis of the mixture of inositol phosphates from corn steep water.

  2. Autohydrolysis Pretreatment of Lignocellulosic Biomass for Bioethanol Production (United States)

    Han, Qiang

    Autohydrolysis, a simple and environmental friendly process, has long been studied but often abandoned as a financially viable pretreatment for bioethanol production due to the low yields of fermentable sugars at economic enzyme dosages. The introduction of mechanical refining can generate substantial improvements for autohydrolysis process, making it an attractive pretreatment technology for bioethanol commercialization. In this study, several lignocellulosic biomass including wheat straw, switchgrass, corn stover, waste wheat straw have been subjected to autohydrolysis pretreatment followed by mechanical refining to evaluate the total sugar recovery at affordable enzyme dosages. Encouraging results have been found that using autohydrolysis plus refining strategy, the total sugar recovery of most feedstock can be as high as 76% at 4 FPU/g enzymes dosages. The mechanical refining contributed to the improvement of enzymatic sugar yield by as much as 30%. Three non-woody biomass (sugarcane bagasse, wheat straw, and switchgrass) and three woody biomass (maple, sweet gum, and nitens) have been subjected to autohydrolysis pretreatment to acquire a fundamental understanding of biomass characteristics that affect the autohydrolysis and the following enzymatic hydrolysis. It is of interest to note that the nonwoody biomass went through substantial delignification during autohydrolysis compared to woody biomass due to a significant amount of p-coumaric acid and ferulic acid. It has been found that hardwood which has a higher S/V ratio in the lignin structure tends to have a higher total sugar recovery from autohydrolysis pretreatment. The economics of bioethanol production from autohydrolysis of different feedstocks have been investigated. Regardless of different feedstocks, in the conventional design, producing bioethanol and co-producing steam and power, the minimum ethanol revenues (MER) required to generate a 12% internal rate of return (IRR) are high enough to

  3. Effect of autohydrolysis on the wettability, absorbility and further alkali impregnation of poplar wood chips. (United States)

    Xu, Ningpan; Liu, Wei; Hou, Qingxi; Wang, Peiyun; Yao, Zhirong


    Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation.

  4. Optimization of autohydrolysis conditions to extract antioxidant phenolic compounds from spent coffee grounds

    DEFF Research Database (Denmark)

    Ballesteros, Lina F.; Ramirez, Monica J.; Orrego, Carlos E.


    Autohydrolysis, which is an eco-friendly technology that employs only water as extraction solvent, was used to extract antioxidant phenolic compounds from spent coffee grounds (SCG). Experimental assays were carried out using different temperatures (160–200 °C), liquid/solid ratios (5–15 ml/g SCG...


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    Jung Myoung Lee


    Full Text Available Coastal Bermuda grass (CBG is an agricultural residue with considerable potential as a feedstock for lignocellulosic-based ethanol. The treatment of biomass with water at high temperature, termed autohydrolysis, can be used to recover sugars in the filtrate and to improve enzyme digestibility of the pretreated solids. The effect of a two- stage autohydrolysis process with respect to total sugar recovery relative to a one stage process was investigated. CBG was subjected to lab scale one-stage (150, 160, and 170 C and two-stage (150/170 C and 160/170 C isothermal autohydrolysis processes followed by enzyme hydrolysis on the residual solids with different loadings (5 to 30 FPU/g. Two-stage autohydrolysis (160/170 C solubilized 94.2% of the hemicellulose based on the original CBG material but only 17.7% of the cellulose and 30.4% of the lignin. Increases in the severity factor (a combination of time and temperature of autohydrolysis pretreatments decreased the recoverable carbohydrates and total solids. Two-stage autohydrolysis enhanced enzyme digestibility of the cellulose in pretreated solids relative to one-stage autohydrolysis, especially at higher values of FPU/g. The overall total theoretical sugar recovery achievable by the two stage process was 57.8% and for the one stage process only 51.6% with 30 FPU/g. This marginal increase would have to be considered relative to increased complexity of operations when deciding whether to implement one or two stage autohydrolysis.

  6. New perspectives for Paulownia fortunei L. valorisation of the autohydrolysis and pulping processes. (United States)

    Caparrós, S; Díaz, M J; Ariza, J; López, F; Jiménez, L


    This paper will consider the influence of the temperature of autohydrolysis or hydrothermal process from Paulownia fortunei L. to obtain a valuable liquid phase and a suitable solid phase to produce pulp. The solid phase resulting of autohydrolysis was subjected to organosolv pulping process and formed paper sheets, analyzing the influence of operational variables (viz., ethanol concentration, temperature and pulping time) on the yield, viscosity, tensile index, burst index, tear index and brightness. Maximum glucose and xylose contents and minimum paper sheets characteristic loss have been obtained at 190 degrees C authohydrolysis temperature. Suitable characteristics of paper sheets and acceptable yield, viscosity and kappa number of pulp could be obtained by operating at 180 degrees C temperature, 30min pulping time and 20% ethanol concentration. Under those conditions sheets paper with 27.4% ISO brightness, 28.87Nm/g tensile index, 1.22kPam(2)/g burst index and 1.23kNm(2)/g tear index could be obtained.

  7. Optimization of sugarcane bagasse autohydrolysis for methane production from hemicellulose hydrolyzates in a biorefinery concept. (United States)

    Baêta, Bruno Eduardo Lôbo; Lima, Diego Roberto Sousa; Adarme, Oscar Fernando Herrera; Gurgel, Leandro Vinícius Alves; Aquino, Sérgio Francisco de


    This study aimed to optimize through design of experiments, the process variables (temperature - T, time - t and solid-to-liquid ratio - SLR) for sugarcane bagasse (SB) autohydrolysis (AH) to obtain hemicellulose hydrolyzates (HH) prone to anaerobic digestion (AD) and biochemical methane production (BMP). The results indicated that severe AH conditions, which lead to maximum hemicelluloses dissolution and sugar content in the HH, were not the best for BMP, probably due to the accumulation of toxic/recalcitrant compounds (furans and lignin). Mild AH conditions (170°C, 35min and SLR=0.33) led to the highest BMP (0.79Nm(3)kg TOC(-1)), which was confirmed by the desirability tool. HH produced by AH carried out at the desired condition DC2 (178.6°C, 43.6min and SLR=0.24) showed the lowest accumulation of inhibitory compounds and volatile fatty acids (VFA) and highest BMP (1.56Nm(3)kg TOC(-1)). The modified Gompertz model best fit the experimental data and led to a maximum methane production rate (R) of 2.6mmol CH4d(-1) in the best condition.

  8. Evaluation of agave bagasse recalcitrance using AFEX™, autohydrolysis, and ionic liquid pretreatments. (United States)

    Perez-Pimienta, Jose A; Flores-Gómez, Carlos A; Ruiz, Héctor A; Sathitsuksanoh, Noppadon; Balan, Venkatesh; da Costa Sousa, Leonardo; Dale, Bruce E; Singh, Seema; Simmons, Blake A


    A comparative analysis of the response of agave bagasse (AGB) to pretreatment by ammonia fiber expansion (AFEX™), autohydrolysis (AH) and ionic liquid (IL) was performed using 2D nuclear magnetic resonance (NMR) spectroscopy, wet chemistry, enzymatic saccharification and mass balances. It has been found that AFEX pretreatment preserved all carbohydrates in the biomass, whereas AH removed 62.4% of xylan and IL extracted 25% of lignin into wash streams. Syringyl and guaiacyl lignin ratio of untreated AGB was 4.3, whereas for the pretreated biomass the ratios were 4.2, 5.0 and 4.7 for AFEX, AH and IL, respectively. Using NMR spectra, the intensity of β-aryl ether units in aliphatic, anomeric, and aromatic regions decreased in all three pretreated samples when compared to untreated biomass. Yields of glucose plus xylose in the major hydrolysate stream were 42.5, 39.7 and 26.9kg per 100kg of untreated AGB for AFEX, IL and AH, respectively.

  9. Biorefinery process for production of paper and oligomers from Leucaena leucocephala K360 with or without prior autohydrolysis. (United States)

    Feria, M J; García, J C; Díaz, M J; Fernández, M; López, F


    Lignocellulosic material from Leucaena leucocephala was subjected to a two-stage fractionation process to obtain a valorized effluent containing hemicellulose derivatives and a solid phase for producing cellulose pulp by conventional soda-anthraquinone delignification. This solid phase allows the production of cellulose pulp, under less rigorous conditions from NaOH-AQ process (177 °C, 21%, 120 min) than without pretreatment delignification (185 °C, 25%, 150 min) and better or similar properties in the paper sheets obtained (yield 27.6 and 34.0%, brightness 39.3 and 31.6% ISO, tensile index 7.8 and 10.5 N m/g, burst index 0.43 and 0.29 MPa m(2)/kg with and without previous autohydrolysis) have be found. Also, the first autohydrolysis stage allows up to 46.6% of the initial hemicellulose in the raw material to be extracted as xylooligomers, xylose and furfural into the liquid phase.

  10. Analysis of by-product formation and sugar monomerization in sugarcane bagasse pretreated at pilot plant scale: Differences between autohydrolysis, alkaline and acid pretreatment

    NARCIS (Netherlands)

    Pol, van der E.C.; Bakker, R.; Zeeland, van A.N.T.; Sanchez Garcia, D.; Punt, A.M.; Eggink, G.


    Sugarcane bagasse is an interesting feedstock for the biobased economy since a large fraction is polymerized sugars. Autohydrolysis, alkaline and acid pretreatment conditions combined with enzyme hydrolysis were used on lignocellulose rich bagasse to acquire monomeric. By-products found after pretre

  11. Evaluation of jumbo squid (Dosidicus gigas byproduct hydrolysates obtained by acid-enzymatic hydrolysis and by autohydrolysis in practical diets for Pacific white shrimp (Litopenaeus vannamei

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    Mayra Lizett González-Félix


    Full Text Available The marine bioprocessing industry offers great potential to utilize byproducts for fish meal replacement in aquafeeds. Jumbo squid is an important fishery commodity in Mexico, but only the mantle is marketed. Head, fins, guts and tentacles are discarded in spite of being protein-rich byproducts. This study evaluated the use of two jumbo squid byproduct hydrolysates obtained by acid-enzymatic hydrolysis (AEH and by autohydrolysis (AH as ingredients in practical diets for shrimp. The hydrolysates were included at levels of 2.5 and 5.0% of the diet dry weight in four practical diets, including a control diet without hydrolysate. Shrimp growth and survival were not significantly affected by the dietary treatments. Postharvest quality of abdominal muscle was evaluated in terms of proximate composition and sensory evaluation. Significantly higher crude protein was observed in the muscle of shrimp fed the highest hydrolysate levels, AH 5% (204.8 g kg- 1 or AEH 5% (201.3 g kg- 1. Sensory analysis of cooked muscle showed significant differences for all variables evaluated: color, odor, flavor, and firmness. It was concluded that Jumbo squid byproducts can be successfully processed by autohydrolysis or acid-enzymatic hydrolysis, and that up to 5.0% of the hydrolysates can be incorporated into shrimp diets without affecting growth or survival.

  12. Interactions between Cellulolytic Enzymes with Native, Autohydrolysis, and Technical Lignins and the Effect of a Polysorbate Amphiphile in Reducing Nonproductive Binding. (United States)

    Fritz, Consuelo; Ferrer, Ana; Salas, Carlos; Jameel, Hasan; Rojas, Orlando J


    Understanding enzyme-substrate interactions is critical in designing strategies for bioconversion of lignocellulosic biomass. In this study we monitored molecular events, in situ and in real time, including the adsorption and desorption of cellulolytic enzymes on lignins and cellulose, by using quartz crystal microgravimetry and surface plasmon resonance. The effect of a nonionic surface active molecule was also elucidated. Three lignin substrates relevant to the sugar platform in biorefinery efforts were considered, namely, hardwood autohydrolysis cellulolytic (HWAH), hardwood native cellulolytic (MPCEL), and nonwood native cellulolytic (WSCEL) lignin. In addition, Kraft lignins derived from softwoods (SWK) and hardwoods (HWK) were used as references. The results indicated a high affinity between the lignins with both, monocomponent and multicomponent enzymes. More importantly, the addition of nonionic surfactants at concentrations above their critical micelle concentration reduced remarkably (by over 90%) the nonproductive interactions between the cellulolytic enzymes and the lignins. This effect was hypothesized to be a consequence of the balance of hydrophobic and hydrogen bonding interactions. Moreover, the reduction of surface roughness and increased wettability of lignin surfaces upon surfactant treatment contributed to a lower affinity with the enzymes. Conformational changes of cellulases were observed upon their adsorption on lignin carrying preadsorbed surfactant. Weak electrostatic interactions were determined in aqueous media at pH between 4.8 and 5.5 for the native cellulolytic lignins (MPCEL and WSCEL), whereby a ∼20% reduction in the enzyme affinity was observed. This was mainly explained by electrostatic interactions (osmotic pressure effects) between charged lignins and cellulases. Noteworthy, adsorption of nonionic surfactants onto cellulose, in the form cellulose nanofibrils, did not affect its hydrolytic conversion. Overall, our results

  13. Dilute Acid and Autohydrolysis Pretreatment (United States)

    Yang, Bin; Wyman, Charles E.

    Exposure of cellulosic biomass to temperatures of about 120-210°C can remove most of the hemicellulose and produce cellulose-rich solids from which high glucose yields are possible with cellulase enzymes. Furthermore, the use of dilute sulfuric acid in this pretreatment operation can increase recovery of hemicellulose sugars substantially to about 85-95% of the maximum possible versus only about 65% if no acid is employed. The use of small-diameter tubes makes it possible to employ high solids concentrations similar to those preferred for commercial operations, with rapid heat-up, good temperature control, and accurate closure of material balances. Mixed reactors can be employed to pretreat larger amounts of biomass than possible in such small-diameter tubes, but solids concentrations are limited to about 15% or less to provide uniform temperatures. Pretreatment of large amounts of biomass at high solids concentrations is best carried out using direct steam injection and rapid pressure release, but closure of material balances in such “steam gun” devices is more difficult. Although flow of water alone or containing dilute acid is not practical commercially, such flow-through configurations provide valuable insight into biomass deconstruction kinetics not possible in the batch tubes, mixed reactors, or steam gun systems.

  14. Autohydrolysis of plant xylans by apoplastic expression of thermophilic bacterial endo-xylanases

    DEFF Research Database (Denmark)

    Borkhardt, Bernhard; Harholt, Jesper; Ulvskov, Peter Bjarne


    The genes encoding the two endo-xylanases XynA and XynB from the thermophilic bacterium Dictyoglomus thermophilum were codon optimized for expression in plants. Both xylanases were designed to be constitutively expressed under the control of the CaMV 35S promoter and targeted to the apoplast. Tra...

  15. Can Acceptable Pulp be Obtained from Eucalyptus globulus Wood Chips after Hemicellulose Extraction?

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    Francisco López


    Full Text Available This study investigates the operating conditions used in the soda-anthraquinone pulping of Eucalyptus globulus wood after autohydrolysis pretreatment on the yield, kappa number, and brightness of the resulting unbleached pulp. Moreover, strength-related properties of the resulting handsheets was examined to identify the best pulping conditions and compare the outcome with that of a conventional soda-anthraquinone pulping process. The paper strength properties of the pulp were similar to or better than papers made from soda-AQ delignified pulps conducted in a single step. Also, a liquid fraction with a substantial content in hemicellulosic extracts was recovered in the simplified process. Autohydrolysis of the raw material facilitates carrying out soda-AQ pulping under milder conditions. In addition, autohydrolysis improves other properties relative to paper from raw cellulose pulp. Yield, kappa number, and brightness for pulp from solid residues of autohydrolysed eucalyptus wood were similar to those for pulp from untreated eucalyptus wood.

  16. Integral valorization of Leucaena diversifolia by hydrothermal and pulp processing. (United States)

    Feria, Manuel J; Alfaro, Ascensión; López, Francisco; Pérez, Antonio; García, Juan C; Rivera, Amanda


    Wood from the leguminous tree, Leucaena diversifolia, was subjected to hydrothermal treatment (autohydrolysis) at 160-180 °C for 0-30 min followed by ethanol-soda-anthraquinone delignification. The liquid phase contained 18.65 g of sugars per liter, and the solid phase had a gross heating value of 19.083 MJ/kg, but could also be used as a source of cellulose pulp for the production of paper with tear, burst, and tensile indexes of 2.4 N m2/kg, 2.6 MPa m2/kg and 40.7 kN m/kg, respectively. L. diversifolia lends itself readily to valorization for energy production, and also to integral, fractional exploitation by autohydrolysis and ethanol-soda-anthraquinone delignification, which can additionally bring environmental benefits to cropping zones.

  17. Countercurrent Process for Lignin Separation from Biomass Matrix

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    Kiran Kadam; Ed Lehrburger


    The overall goal of the project was to test the concept of using a twin-screw extruder to conduct autohydrolysis pretreatment of wheat straw in countercurrent fashion, demonstrate in situ solid/liquid separation, and produce a low-lignin cellulose product using ethanol as an extractant. The resultant solid product is suitable for sugar production through enzymatic hydrolysis and for pulp applications. Pilot-scale equipment was used to successfully demonstrate the process both for sugar and pulp applications.

  18. Rapid Mass Spectrometric Analysis of a Novel Fucoidan, Extracted from the Brown Alga Coccophora langsdorfii

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    Stanislav D. Anastyuk


    Full Text Available The novel highly sulfated (35% fucoidan fraction Cf2 , which contained, along with fucose, galactose and traces of xylose and uronic acids was purified from the brown alga Coccophora langsdorfii. Its structural features were predominantly determined (in comparison with fragments of known structure by a rapid mass spectrometric investigation of the low-molecular-weight fragments, obtained by “mild” (5 mg/mL and “exhaustive” (maximal concentration autohydrolysis. Tandem matrix-assisted laser desorption/ionization mass spectra (MALDI-TOF/TOFMS of fucooligosaccharides with even degree of polymerization (DP, obtained by “mild” autohydrolysis, were the same as that observed for fucoidan from Fucus evanescens, which have a backbone of alternating (1 → 3- and (1 → 4 linked sulfated at C-2 and sometimes at C-4 of 3-linked α-L-Fucp residues. Fragmentation patterns of oligosaccharides with odd DP indicated sulfation at C-2 and at C-4 of (1 → 3 linked α-L-Fucp residues on the reducing terminus. Minor sulfation at C-3 was also suggested. The “exhaustive” autohydrolysis allowed us to observe the “mixed” oligosaccharides, built up of fucose/xylose and fucose/galactose. Xylose residues were found to occupy both the reducing and nonreducing termini of FucXyl disaccharides. Nonreducing galactose residues as part of GalFuc disaccharides were found to be linked, possibly, by 2-type of linkage to fucose residues and were found to be sulfated, most likely, at position C-2.


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    Carlos Vila,


    Full Text Available To assess the feasibility of implementing hemicellulose recovery stages in kraft mills, Eucalyptus globulus wood samples were subjected to aqueous treatments with hot, compressed water (autohydrolysis processing to achieve partial dissolution of xylan. Autohydrolyzed solids were subjected to kraft pulping under selected conditions to yield a pulp of low kappa number, and to an optimized TCF bleaching sequence made up of three stages (alkaline oxygen delignification, chelating, and pressurized hydrogen peroxide, with minimized additions of pulping and bleaching chemicals. The final product had a relatively low kappa number (1.4, 641 mL/g ISO intrinsic viscosity, and 86.4% brightness.

  20. Sulfated oligosaccharide structures, as determined by NMR techniques

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    Noseda, M.D.; Duarte, M.E.R.; Tischer, C.A.; Gorin, P.A.J. [Parana Univ., Curitiba, PR (Brazil). Dept. De Bioquimica; Cerezo, A.S. [Buenos Aires Univ. Nacional (Argentina). Dept. de Quimica Organica


    Carrageenans are sulfated polysaccharides, produced by red seaweeds (Rhodophyta), that have important biological and physico-chemical properties. Using partial autohydrolysis, we obtained sulfated oligosaccharides from a {lambda}-carrageenan (Noseda and Cerezo, 1993). These oligosaccharides are valuable not only for the study of the structures of the parent carrageenans but also for their possible biological activities. In this work we determined the chemical structure of one of the sulfated oligosaccharides using 1D and 2D NMR techniques. (author) 4 refs., 8 figs., 1 tabs.

  1. Structural analysis of a highly sulfated fucan from the brown alga Laminaria cichorioides by tandem MALDI and ESI mass spectrometry. (United States)

    Anastyuk, Stanislav D; Shevchenko, Natalia M; Nazarenko, Eugene L; Imbs, Tatyana I; Gorbach, Vladimir I; Dmitrenok, Pavel S; Zvyagintseva, Tatyana N


    Water-soluble polysaccharide fractions were extracted from the brown alga Laminaria cichorioides. Samples were collected monthly from May to October in Troitsa Bay (Japan Sea, Russia). Analysis showed that the content and monosaccharide composition of the fractions changed with the collection season. Fucoidan was isolated and purified from the most fucose-rich fraction, collected in July, and subjected to autohydrolysis to obtain fucooligosaccharides, suitable for mass-spectrometric analysis. Both ESIMS and MALDI-TOFMS analyses show that multisulfated (up to 3) fucooligosaccharides with polymerization degree n from 2 to 5, including mono- and disulfated-fucose residues, were the major products of autohydrolysis. The structural features of the fucooligosaccharides and their alditol derivatives were elucidated by tandem MALDI-TOFMS and ESIMS. The results obtained allowed us to conclude that fragments of the fucoidan, collected in July, were predominantly linked with a (1→3)-type of linkage and that sulfate groups occupied mostly C-2 or C-2/C-4 of the α-l-fucose residues.


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    Juan Carlos García


    Full Text Available A trihybrid clone of Paulownia fortunei x tormentosa x elongata was used for pulp and paper production using the soda-anthraquinone (AQ process, comparing the results with those from Paulownia fortunei. An autohydrolysis process had been previously carried out on this raw material. A composite central experimental design and a multiple regression were used for modeling and optimizing the process. A valuable liquid phase could be obtained from the autohydrolysis process of Paulownia, trying to minimize cellulose degradation for pulp and paper production. A compromise to maximize the glucan and minimize the xylan contents in the postautohydrolysis solid phase could be achieved at 187.5ºC and 15 minutes. A suitable cellulosic pulp with kappa number ranging from 12.2 to 69.2 and ISO brightness from 18.2 to 30.6% presented better results than those from other studies. Regarding handsheets physical properties (tensile index 37.3 N•m/g and viscosity (848 cm3/g, significant improvements could be obtained when compared with previous results of a similar process using Paulownia fortunei or Paulownia elongata.

  3. Energy from Biomass for Conversion of Biomass (United States)

    Abolins, J.; Gravitis, J.


    Along with estimates of minimum energy required by steam explosion pre-treatment of biomass some general problems concerning biomass conversion into chemicals, materials, and fuels are discussed. The energy necessary for processing biomass by steam explosion auto-hydrolysis is compared with the heat content of wood and calculated in terms of the amount of saturated steam consumed per unit mass of the dry content of wood biomass. The fraction of processed biomass available for conversion after steam explosion pre-treatment is presented as function of the amount of steam consumed per unit mass of the dry content of wood. The estimates based on a simple model of energy flows show the energy required by steam explosion pre-treatment of biomass being within 10% of the heat content of biomass - a realistic amount demonstrating that energy for the process can be supplied from a reasonable proportion of biomass used as the source of energy for steam explosion pre-treatment.


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    Anna Ebringerová


    Full Text Available The isolation of non-cellulosic polysaccharides from both almond shells and their solid residue after autohydrolysis using a two-step alkaline extraction without and in combination with short ultrasonic treatment was investigated. The obtained polysaccharide preparations were characterized by yield, chemical composition and structural features, and the antioxidant activity of the water-soluble preparations was discussed in relation to the content of phenolics. The results suggested that, depending on the extraction conditions used, xylan associated to various extent with pectic polysaccharides and phenolics can be prepared, and the reaction time significantly shortened by application of ultrasound. The xylan polymers might serve as biopolymer sources in native form or after targeted modification for production of value-added substances and polysaccharide-based antioxidants, applicable in food, cosmetics and other areas.

  5. Fucoidans from brown alga Fucus evanescens: structure and biological activity

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    Roza Menshova


    Full Text Available Brown alga Fucus evanescens, widespread in the Far Eastern seas of Russia, is valuable source of sulfated polysaccharides – fucoidans with beneficial biological activities. The most homogenous fraction of fucoidan from F. evanescens was shown to be molecule containing linear main chain of alternating 2-sulfated 1,3- and 1,4-linked α-L-fucose residues. Few sulfate groups were found in position 4 of some 1,3-linked fucose residues. Acetyl groups occupied free C-3 of 1,4-linked residues and/or the C-4 of 1,3-linked fucose residues. Enzymatic hydrolysis, mild acid hydrolysis and autohydrolysis of native fucoidan were used for elucidation of the fine structural characteristics of fucoidan from F. evanescens. The aim of this review to summarize published data on biological activities of fucoidan from F. evanescens: antiviral, anticoagulant, thrombolytic, hepatoprotective, immunomodulatory, anticancer, and their practical application.


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    Joni Tapani Lehto,


    Full Text Available Carbohydrate-containing hydrolysates (1.1 to 14.9% of wood dry matter obtained from autohydrolysis (at 130 to 150°C for 30 to 120 minutes of birch (Betula pendula chips prior to pulping were purified with respect to non-carbohydrate materials, without carbohydrate losses, either by ethyl acetate extraction or XAD-4 resin treatment. In the former case, about 50% of lignin and practically all the furanoic compounds (2-furaldehyde and 5-(hydroxymethylfurfural could be removed, whereas in the latter case, the corresponding amounts were about 30% and 50 to 90%, respectively. A partial recovery of various unsaturated impurities is of importance, because they may act as inhibitors when biochemically converting carbohydrates in hydrolysates into value-added products.

  7. Production and purification of xylooligosaccharides from oil palm empty fruit bunch fibre by a non-isothermal process. (United States)

    Ho, Ai Ling; Carvalheiro, Florbela; Duarte, Luís C; Roseiro, Luísa B; Charalampopoulos, Dimitris; Rastall, Robert A


    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 °C. The highest XOS concentration, 17.6g/L which relayed from solubilisation of 63 g/100 g xylan was achieved at 210 °C and there was a minimum amount of xylose and furfural being produced. The chromatographic purification which was undertaken to purify the oligosaccharide-rich liquor resulted in a product with 74-78% purity, of which 83-85% was XOS with degree of polymerisation (DP) between 5 and 40.

  8. Fast, Continuous, and High-Throughput (Bio)Chemical Activity Assay for N-Acyl-l-Homoserine Lactone Quorum-Quenching Enzymes (United States)

    Last, Daniel; Krüger, Georg H. E.; Dörr, Mark


    ABSTRACT Quorum sensing, the bacterial cell-cell communication by small molecules, controls important processes such as infection and biofilm formation. Therefore, it is a promising target with several therapeutic and technical applications besides its significant ecological relevance. Enzymes inactivating N-acyl-l-homoserine lactones, the most common class of communication molecules among Gram-negative proteobacteria, mainly belong to the groups of quorum-quenching lactonases or quorum-quenching acylases. However, identification, characterization, and optimization of these valuable biocatalysts are based on a very limited number of fundamentally different methods with their respective strengths and weaknesses. Here, a (bio)chemical activity assay is described, which perfectly complements the other methods in this field. It enables continuous and high-throughput activity measurements of purified and unpurified quorum-quenching enzymes within several minutes. For this, the reaction products released by quorum-quenching lactonases and quorum-quenching acylases are converted either by a secondary enzyme or by autohydrolysis to l-homoserine. In turn, l-homoserine is detected by the previously described calcein assay, which is sensitive to α-amino acids with free N and C termini. Besides its establishment, the method was applied to the characterization of three previously undescribed quorum-quenching lactonases and variants thereof and to the identification of quorum-quenching acylase-expressing Escherichia coli clones in an artificial library. Furthermore, this study indicates that porcine aminoacylase 1 is not active toward N-acyl-l-homoserine lactones as published previously but instead converts the autohydrolysis product N-acyl-l-homoserine. IMPORTANCE In this study, a novel method is presented for the identification, characterization, and optimization of quorum-quenching enzymes that are active toward N-acyl-l-homoserine lactones. These are the most common

  9. Tomato fruit cell wall : I. Use of purified tomato polygalacturonase and pectinmethylesterase to identify developmental changes in pectins. (United States)

    Koch, J L; Nevins, D J


    Cell wall isolation procedures were evaluated to determine their effect on the total pectin content and the degree of methylesterification of tomato (Lycopersicon esculentum L.) fruit cell walls. Water homogenates liberate substantial amounts of buffer soluble uronic acid, 5.2 milligrams uronic acid/100 milligrams wall. Solubilization appears to be a consequence of autohydrolysis mediated by polygalacturonase II, isoenzymes A and B, since the uronic acid release from the wall residue can be suppressed by homogenization in the presence of 50% ethanol followed by heating. The extent of methylesterification in heat-inactivated cell walls, 94 mole%, was significantly greater than with water homogenates, 56 mole%. The results suggest that autohydrolysis, mediated by cell wall-associated enzymes, accounts for the solubilization of tomato fruit pectin in vitro. Endogenous enzymes also account for a decrease in the methylesterification during the cell wall preparation. The heat-inactivated cell wall preparation was superior to the other methods studied since it reduces beta-elimination during heating and inactivates constitutive enzymes that may modify pectin structure. This heat-inactivated cell wall preparation was used in subsequent enzymatic analysis of the pectin structure. Purified tomato fruit polygalacturonase and partially purified pectinmethylesterase were used to assess changes in constitutive substrates during tomato fruit ripening. Polygalacturonase treatment of heat-inactivated cell walls from mature green and breaker stages released 14% of the uronic acid. The extent of the release of polyuronides by polygalacturonase was fruit development stage dependent. At the turning stage, 21% of the pectin fraction was released, a value which increased to a maximum of 28% of the uronides at the red ripe stage. Pretreatment of the walls with purified tomato pectinesterase rendered walls from all ripening stages equally susceptible to polygalacturonase. Quantitatively

  10. Steam explosion pretreatment of triticale (× Triticosecale Wittmack) straw for sugar production. (United States)

    Agudelo, Roberto A; García-Aparicio, María P; Görgens, Johann F


    Triticale, a non-food based, low-cost and well-adapted crop in marginal lands has been considered as a potential 1G and 2G feedstock for bio-ethanol production. In this work, triticale straw was evaluated as a source of fermentable sugars by combination of uncatalyzed steam explosion and enzymatic hydrolysis. Pretreatment conditions with severities from 3.05 to 4.12 were compared in order to identify conditions that favour the recovery of hemicellulose-derived sugars, cellulose digestibility or the combined sugars yield (CSY) from the pretreatment-enzymatic hydrolysis. Xylose oligosaccharide was the major sugar in hydrolysates from all pretreatment conditions. Maximum hemicellulose-sugars recovery (52% of the feedstock content) was obtained at 200 °C and 5 min. The highest cellulose digestibility (95%) was found at 200 °C - 15 min, although glucose recovery from hydrolysis was maximised at 200 °C - 10 min (digestibility >92%) due to higher mass yield of pretreated solids. The maximum CSY (nearly 77% of theoretical content) was obtained at 200 °C - 5 min. Sugar loss after pretreatment was observed to higher extent at harsher severities. However, the concentrations of sugar degradation products and acetic acid were at levels below tolerance limits of the downstream biological conversions. Steam explosion pretreatment without acid impregnation is a good technology for production of fermentable sugars from triticale straw. This work provides foundation for future autohydrolysis steam explosion optimization studies to enhanced sugars recovery and digestibility of triticale straw.

  11. Effect of steam explosion and enzymatic pre-treatments on pulping and bleaching of Hesperaloe funifera. (United States)

    Martín-Sampedro, R; Eugenio, M E; Villar, J C


    A non-wood raw material with high potential for pulp and paper applications (Hesperaloe funifera) was subjected to a steam explosion pre-treatment, and the subsequent effect of this pretreatment on biopulping and biobleaching was studied. An increase in the delignification rate, bigger than that reported for autohydrolysis and acid hydrolysis pre-treatments, and a reduction in chemical consumption were found during kraft pulping of the exploded samples. However, biopulping with the laccase-mediator system (LMS) did not lead to a reduction in the kappa number in either non-exploded or exploded unbleached pulps. On the other hand, the steam explosion pretreatment boosted the advantages of the LMS pre-treatment (decrease in kappa number and increase in brightness) favored biobleaching, with a 53.1% delignification rate and a final brightness of 67% ISO. Finally, the steam explosion pre-treatment also improved the color properties of the bleached pulp and reduced the hydrogen peroxide consumption by 24.6%.

  12. Influence of steaming explosion time on the physic-chemical properties of cellulose from Lespedeza stalks (Lespedeza crytobotrya). (United States)

    Wang, Kun; Jiang, Jian-Xin; Xu, Feng; Sun, Run-Cang


    The synergistic effect of steam explosion pretreatment and sodium hydroxide post-treatment of Lespedeza stalks (Lespedeza crytobotrya) has been investigated in this study. In this case, Lespedeza stalks were firstly exploded at a fixed steam pressure (22.5 kg/m(2)) for 2-10 min. Then the steam-exploded Lespedeza stalks was extracted with 1 M NaOH at 50 degrees C for 3 h with a shrub to water ratio of 1:20 (g/ml), which yielded 57.3%, 53.1%, 55.4%, 52.8%, 53.2%, and 56.4% (% dry weight) cellulose rich fractions, comparing to 68.0% from non-steam-exploded material. The content of glucose in cellulose rich residues increased with increment of the steaming time and reached to 94.10% at the most severity. The similar increasing trend occurred during the dissolution of hemicelluloses. It is evident that at shorter steam explosion time, autohydrolysis mainly occurred on the hemicelluloses and the amorphous area of cellulose. The crystalline region of cellulose was depolymerized under a prolonged incubation time. The characteristics of the cellulose rich fractions in terms of FT-IR and CP/MAS (13)C NMR spectroscopy and thermal analysis were discussed, and the surface structure was also investigated by SEM.

  13. Production of cellulosic ethanol from sugarcane bagasse by steam explosion: Effect of extractives content, acid catalysis and different fermentation technologies. (United States)

    Neves, P V; Pitarelo, A P; Ramos, L P


    The production of cellulosic ethanol was carried out using samples of native (NCB) and ethanol-extracted (EECB) sugarcane bagasse. Autohydrolysis (AH) exhibited the best glucose recovery from both samples, compared to the use of both H3PO4 and H2SO4 catalysis at the same pretreatment time and temperature. All water-insoluble steam-exploded materials (SEB-WI) resulted in high glucose yields by enzymatic hydrolysis. SHF (separate hydrolysis and fermentation) gave ethanol yields higher than those obtained by SSF (simultaneous hydrolysis and fermentation) and pSSF (pre-hydrolysis followed by SSF). For instance, AH gave 25, 18 and 16 g L(-1) of ethanol by SHF, SSF and pSSF, respectively. However, when the total processing time was taken into account, pSSF provided the best overall ethanol volumetric productivity of 0.58 g L(-1) h(-1). Also, the removal of ethanol-extractable materials from cane bagasse had no influence on the cellulosic ethanol production of SEB-WI, regardless of the fermentation strategy used for conversion.

  14. Extraction of valuable compounds from mangosteen pericarps by hydrothermal assisted sonication (United States)

    Machmudah, Siti; Lestari, Sarah Duta; Shiddiqi, Qifni Yasa'Ash; Widiyastuti, Winardi, Sugeng; Wahyudiono, Kanda, Hideki; Goto, Motonobu


    Valuable compounds, such as xanthone and phenolic compounds, from mangosteen pericarps was extracted by hydrothermal treatment at temperatures of 120-160 °C and pressures of 5 MPa using batch and semi-batch extractor. This method is a simple and environmentally friendly extraction method requiring no chemicals other than water. Under these conditions, there is possibility for the formation of phenolic compounds from mangosteen pericarps from decomposition of bounds between lignin, cellulose, and hemicellulose via autohydrolysis. In order to increase the amount of extracted valuable compounds, sonication pre-treament was performed prior to the hydrothermal extraction process. 30 min of sonication pre-treatment could increase significantly the amount of xanthone and phenolic compounds mangosteen pericarps extraction. In batch-system, the xanthone recovery approach to 100 % at 160 °C with 30 min sonication pre-treatment for 150 min extraction time. Under semi-batch process, the total phenolic compounds in the extract was 217 mg/g sample at 160 °C with 30 min sonication pre-treatment for 150 min total extraction time. The results revealed that hydrothermal extraction assisted sonication pre-treatment is applicable method for the isolation of polyphenolic compounds from other types of biomass and may lead to an advanced plant biomass components extraction technology.

  15. Plant biotechnology for lignocellulosic biofuel production. (United States)

    Li, Quanzi; Song, Jian; Peng, Shaobing; Wang, Jack P; Qu, Guan-Zheng; Sederoff, Ronald R; Chiang, Vincent L


    Lignocelluloses from plant cell walls are attractive resources for sustainable biofuel production. However, conversion of lignocellulose to biofuel is more expensive than other current technologies, due to the costs of chemical pretreatment and enzyme hydrolysis for cell wall deconstruction. Recalcitrance of cell walls to deconstruction has been reduced in many plant species by modifying plant cell walls through biotechnology. These results have been achieved by reducing lignin content and altering its composition and structure. Reduction of recalcitrance has also been achieved by manipulating hemicellulose biosynthesis and by overexpression of bacterial enzymes in plants to disrupt linkages in the lignin-carbohydrate complexes. These modified plants often have improved saccharification yield and higher ethanol production. Cell wall-degrading (CWD) enzymes from bacteria and fungi have been expressed at high levels in plants to increase the efficiency of saccharification compared with exogenous addition of cellulolytic enzymes. In planta expression of heat-stable CWD enzymes from bacterial thermophiles has made autohydrolysis possible. Transgenic plants can be engineered to reduce recalcitrance without any yield penalty, indicating that successful cell wall modification can be achieved without impacting cell wall integrity or plant development. A more complete understanding of cell wall formation and structure should greatly improve lignocellulosic feedstocks and reduce the cost of biofuel production.

  16. Production, Purification, and in Vitro Evaluation of the Prebiotic Potential of Arabinoxylooligosaccharides from Brewer's Spent Grain. (United States)

    Gómez, Belén; Míguez, Beatriz; Veiga, Adán; Parajó, Juan Carlos; Alonso, José Luís


    Brewer's spent grain (BSG) samples were subjected to a two-step aqueous processing (starch extraction and autohydrolysis) in order to assess their potential as a raw material for obtaining a mixture of arabinoxylooligosaccharides (AXOS) suitable to be use as prebiotics for elderly. After hydrothermal treatment, the liquors were refined by a sequence of purification and conditioning steps including membrane filtration, enzymatic hydrolysis, and ion exchange. The presence of both substituted (degree of polimerization (DP) = 2-10) and unsubstituted (DP = 2-16) oligosaccharides made up of xylose and arabinose (AXOS) were confirmed in purified mixtures (in which total OS content = 84% w/w) by using chromatographic techniques and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Finally, AXOS were evaluated for their prebiotic activity by in vitro fermentation assays using fecal inocula from elderly people, demonstrating that AXOS were slightly better substrates than FOS, in terms of bacterial population shifts as in the production of SCFA.

  17. Enhancement of amylase production by Aspergillus sp. using carbohydrates mixtures from triticale

    Directory of Open Access Journals (Sweden)

    Dojnov Biljana


    Full Text Available For the purpose of finding a suitable available inducer in combination with starvation, carbohydrate mixtures from triticale was used as inducers and compared with well-known amylase inducers in fungi. Carbohydrate mixtures from triticale induced production of amylase cocktail (α-amylase and glucoamylase in Aspergillus niger, unlike induction with well-known inducers which induce only glucoamylase, showed by zymogram and TLC analysis of carbohydrates mixtures before and after fermentations. Glucoamylase production by A. niger was highest in the presence of extract obtained after autohydrolysis of starch from triticale (95.88 U/mL. Carbohydrate mixtures from triticale induced production of α-amylase in A. oryzae. More α-amylase isoforms were detected upon using complex carbohydrate mixture, compared to induction with maltose or starch. The 48 h induction was the most efficient by using triticale extract (101.35 U/mL. Carbohydrates from triticale extracts can be used as very good cheap amylase inducers. Triticale, still not fully utilized, could be taken into consideration as the inducer in amylase production by Aspergillus sp, such a way it could be used as sole substrate in fermentation. [Projekat Ministarstva nauke Republike Srbije, br. 172048

  18. Thermal gelation of mixed egg yolk/kappa-carrageenan dispersions. (United States)

    Aguilar, J M; Cordobés, F; Raymundo, A; Guerrero, A


    This study aims to evaluate the effect of gum content and pH on the thermal gelation of mixed egg yolk/κ-carrageenan (EY/κC) dispersions, monitored by linear viscoelastic measurements. Heat processing induces dramatic changes in the microstructure and viscoelastic properties of EY/κC systems, which may be attributed to a multistage mechanism that yields an interparticle gel network. An increase in κC content generally induces an enhancement in viscoelasticity. A reduction in pH hinders this enhancement and causes an anticipation of the multistage process, which confirms the importance of the electrostatic interactions of EY/κC dispersions. The viscoelastic properties of EY/κC gels generally fit a master mechanical spectrum, which suggests that the protein matrix generally dominates the microstructure of EY/κC gels. However, SEM images reveal formation of a κC network at low pH, at which some κC autohydrolysis may also play a role. Electrostatic attractions seem to favour interactions among EY aggregates and κC into the carrageenan network.

  19. Efficient acetone-butanol-ethanol production by Clostridium beijerinckii from sugar beet pulp. (United States)

    Bellido, Carolina; Infante, Celia; Coca, Mónica; González-Benito, Gerardo; Lucas, Susana; García-Cubero, María Teresa


    Sugar beet pulp (SBP) has been investigated as a promising feedstock for ABE fermentation by Clostridium beijerinckii. Although lignin content in SBP is low, a pretreatment is needed to enhance enzymatic hydrolysis and fermentation yields. Autohydrolysis at pH 4 has been selected as the best pretreatment for SBP in terms of sugars release and acetone and butanol production. The best overall sugars release yields from raw SBP ranged from 66.2% to 70.6% for this pretreatment. The highest ABE yield achieved was 0.4g/g (5.1g/L of acetone and 6.6g/L butanol) and 143.2g ABE/kg SBP (62.3g acetone and 80.9g butanol) were obtained when pretreated SBP was enzymatically hydrolyzed at 7.5% (w/w) solid loading. Higher solid loadings (10%) offered higher acetone and butanol titers (5.8g/L of acetone and 7.8g/L butanol). All the experiments were carried out under not-controlling pH conditions reaching about 5.3 in the final samples.

  20. Prebiotic xylooligosaccharides from lignocellulosic materials: production, purification and applications – An overview

    Directory of Open Access Journals (Sweden)

    Cristian-Teodor BURUIANĂ


    Full Text Available This paper is a state-of-the-art review and a consolidated source of information regarding the prebiotic potential of xylooligosaccharides (XOS derived from lignocellulosic materials (LCM as bioactive molecules with high-added value for human health. XOS can be obtained by hydrothermal pretreatment (or autohydrolysis, a primary technological step in biological conversion of LCM into value-added products. Purification of XOS is a complex process which aims to remove unwanted compounds and to achieve the necessary degree of polymerization. Proven benefits and positive effects on the human health are mainly in the intestinal microbiota, where food-grade XOS stimulate the growth and proliferation of probiotic bacteria. The main objective of this study was to provide an in-depth overview of the recent published investigations reported in the scientific literature on the production of XOS from xylan-containing LCM by hydrothermal pretreatment, purification of hydrothermally produced XOS and, furthermore, evaluation of the bioactive properties of purified XOS.

  1. Global and grain-specific accumulation of glycoside hydrolase family 10 xylanases in transgenic maize (Zea mays). (United States)

    Gray, Benjamin N; Bougri, Oleg; Carlson, Alvar R; Meissner, Judy; Pan, Shihao; Parker, Matthew H; Zhang, Dongcheng; Samoylov, Vladimir; Ekborg, Nathan A; Michael Raab, R


    In planta expression of cell wall degrading enzymes is a promising approach for developing optimized biomass feedstocks that enable low-cost cellulosic biofuels production. Transgenic plants could serve as either an enzyme source for the hydrolysis of pretreated biomass or as the primary biomass feedstock in an autohydrolysis process. In this study, two xylanase genes, Bacillus sp. NG-27 bsx and Clostridium stercorarium xynB, were expressed in maize (Zea mays) under the control of two different promoters. Severe phenotypic effects were associated with xylanase accumulation in maize, including stunted plants and sterile grains. Global expression of these xylanases from the rice ubiquitin 3 promoter (rubi3) resulted in enzyme accumulation of approximately 0.01 mg enzyme per gram dry weight, or approximately 0.1% of total soluble protein (TSP). Grain-specific expression of these enzymes from the rice glutelin 4 promoter (GluB-4) resulted in higher-level accumulation of active enzyme, with BSX and XynB accumulating up to 4.0% TSP and 16.4% TSP, respectively, in shriveled grains from selected T0 plants. These results demonstrate the potential utility of the GluB-4 promoter for biotechnological applications. The phenotypic effects of xylanase expression in maize presented here demonstrate the difficulties of hemicellulase expression in an important crop for cellulosic biofuels production. Potential alternate approaches to achieve xylanase accumulation in planta without the accompanying negative phenotypes are discussed.

  2. Thermochemical pretreatment of lignocellulose to enhance methane fermentation: II. Evaluation and application of pretreatment model. (United States)

    Baugh, K D; Levy, J A; McCarty, P L


    A model was developed and evaluated as a tool for predicting the formation of soluble products from staged thermochemical treatment of lignocellulosic materials under acidic conditions typical of autohydrolysis. The model was used to predict the general trend of hemi-cellulose and cellulose hydrolysis between pH 2 and 4 and temperatures of 170-230 degrees C, and results were compared with experimental data. When the model was evaluated for this range of temperatures and pH values, results indicated: (1) a relatively low temperature (175 degrees C) during the first stage allows hydrolysis of the hemi-cellulose polysaccharides without significant mono-saccharide decomposition, (2) subsequent stages at higher temperatures (equal or greater than 200 degrees C) are needed for significant cellulose hydrolysis, but glucose decomposition will also occur, and, (3) a pH in the range of 2-2.5 will enhance polysaccharide hydrolysis while limiting monosaccharide decomposition. The model's predictions, indicating that the formation of biodegradable products could be optimized using Pretreatments at pH 2-2.5 for the pH range evaluated, were confirmed in experiments with white fir as a representative lig nocellulose.

  3. Acetate adaptation of clostridia tyrobutyricum for improved fermentation production of butyrate. (United States)

    Jaros, Adam M; Rova, Ulrika; Berglund, Kris A


    Clostridium tyrobutyricum ATCC 25755 is an acidogenic bacterium capable of utilizing xylose for the fermentation production of butyrate. Hot water extraction of hardwood lingocellulose is an efficient method of producing xylose where autohydrolysis of xylan is catalysed by acetate originating from acetyl groups present in hemicellulose. The presence of acetic acid in the hydrolysate might have a severe impact on the subsequent fermentations. In this study the fermentation kinetics of C. tyrobutyricum cultures after being classically adapted for growth at 26.3 g/L acetate equivalents were studied. Analysis of xylose batch fermentations found that even in the presence of high levels of acetate, acetate adapted strains had similar fermentation kinetics as the parental strain cultivated without acetate. The parental strain exposed to acetate at inhibitory conditions demonstrated a pronounced lag phase (over 100 hours) in growth and butyrate production as compared to the adapted strain (25 hour lag) or non-inhibited controls (0 lag). Additional insight into the metabolic pathway of xylose consumption was gained by determining the specific activity of the acetate kinase (AK) enzyme in adapted versus control batches. AK activity was reduced by 63% in the presence of inhibitory levels of acetate, whether or not the culture had been adapted.

  4. Oligosaccharides and monomeric carbohydrates production from olive tree pruning biomass. (United States)

    Mateo, Soledad; Puentes, Juan G; Sánchez, Sebastián; Moya, Alberto J


    Using the severity factor, it has been possible to study cellulose and hemicellulose fractional conversion, sugar yields change and oligosaccharides variation through olive tree pruning biomass pretreatments with acid or liquid hot water under pressure. The temperatures tested were in the range 180-230°C, operation time varying between 0 and 30min and acid concentration used did not exceed 0.05M. Complete hemicellulose solubilization in autohydrolysis was achieved using severity factors (logR0) close to 3.9 (most sugars are like oligomers), while if sulfuric acid 0.025M is employed, this parameter could be smaller (≥3.4). With these treatments, we have obtained cellulose conversions between 30 and 42% from liquid hot water experiments, 40-51% with sulfuric acid 0.025M and 42-57% when the acid concentration was 0.05M. The best results in terms of maximum yield in total sugars, d-glucose and d-xylose, with a low amount of acetic acid and hydroxymethylfurfural, was obtained at 200°C, 0min (what means that there is no time of temperature maintenance, only heating and cooling) and H2SO4 0.025M.

  5. Feasibility study for anaerobic digestion of agricultural crop residues. Dynatech report No. 1935

    Energy Technology Data Exchange (ETDEWEB)

    Ashare, E.; Buivid, M. G.; Wilson, E. H.


    The objective of this study was to provide cost estimates for the pretreatment/digestion of crop residues to fuel gas. A review of agricultural statistics indicated that the crop residues wheat straw, corn stover, and rice straw are available in sufficient quantity to provide meaningful supplies of gas. Engineering economic analyses were performed for digestion of wheat straw, corn stover, and rice straw for small farm-, cooperative-, and industrial scales. The small farm scale processed the residue from an average size US farm (400 acres), and the other sizes were two and three orders of magnitude greater. The results of the analyses indicate that the production of fuel gas from these residues is, at best, economically marginal, unless a credit can be obtained for digester effluent. The use of pretreatment can double the fuel gas output but will not be economically justifiable unless low chemical requirements or low cost chemicals can be utilized. Additional development is necessary in this area. Use of low cost hole-in-the-ground batch digestion results in improved economics for the small farm size digestion system, but not for the cooperative and industrial size systems. Recommendations arising from this study are continued development of autohydrolysis and chemical pretreatment of agricultural crop residues to improve fuel gas yields in an economically feasible manner; development of a low cost controlled landfill batch digestion process for small farm applications; and determination of crop residue digestion by-product values for fertilizer and refeed.

  6. Kinetics of enzyme-catalyzed hydrolysis of steam-exploded sugarcane bagasse. (United States)

    Aguiar, Rodrigo Souza; Silveira, Marcos Henrique Luciano; Pitarelo, Ana Paula; Corazza, Marcos Lucio; Ramos, Luiz Pereira


    This work presents the experimental kinetic data and the fractal modeling of sugarcane bagasse steam treatment and enzymatic hydrolysis. Sugarcane bagasse (50 wt% moisture) was pretreated by autohydrolysis at 210 °C for 4 min. Acid catalysis involved the use of 9.5mg g(-1) of H2SO4 or H3PO4 in relation to the substrate dry mass at these same pretreatment conditions. Unwashed, water-washed and alkali-washed substrates were hydrolyzed at 2.0 wt% using 8 and 15 FPU g(-1) (108.22 and 199.54 mg/g) total solids of a Celluclast 1.5 L and Novozym 188 mixture (Novozymes). The fractal kinetic modeling was used to describe the effect of pretreatment and both washing processes on substrate accessibility. Water and/or alkali washing was not strictly necessary to achieve high hydrolysis efficiencies. Also, the fractal model coefficients revealed that H3PO4 was a better pretreatment catalyst under the experimental conditions used in this study, resulting in the most susceptible substrates for enzymatic hydrolysis.

  7. Comparative biochemical analysis after steam pretreatment of lignocellulosic agricultural waste biomass from Williams Cavendish banana plant (Triploid Musa AAA group). (United States)

    Kamdem, Irénée; Jacquet, Nicolas; Tiappi, Florian Mathias; Hiligsmann, Serge; Vanderghem, Caroline; Richel, Aurore; Jacques, Philippe; Thonart, Philippe


    The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on six combined morphological parts of Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82 ± 3.51 and 49.78 ± 1.39%w/w WCLB dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56 ± 1.33%w/w DM) and SFSC180 (44.47 ± 0.00%w/w DM), while the lowest was found in unpretreated WCLB (22.70 ± 0.71%w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2%w/w of the LF DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210 °C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerization, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors, such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210, were the highest (41 and 21 µg ml(-1), respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments.

  8. Partial Purification and Characterization of a Thermostable β-Mannanase from Aspergillus foetidus

    Directory of Open Access Journals (Sweden)

    Juliana da Conceição Infante de Marco


    Full Text Available An extracellular β-mannanase was isolated from samples of crude extract of the mesophilic fungus Aspergillus foetidus grown on soybean husk as a carbon source. The induction profile showed that β-mannanase reached a maximum activity level (2.0 IU/mL on the 15th day of cultivation. The enzyme was partially purified by ultrafiltration and gel filtration chromatography procedures and was named Man 58. Sodium dodecyl sulfate-polyacrilamide electrophoresis and zymogram analysis of Man 58 showed two bands of approximately 43 and 45 kDa with β-mannanase activity. Ultrafiltration showed that β-mannanase activity was only detected in the concentrated sample. Man 58 was most active at 60 °C and at pH 4.0. It was thermostable in the temperature range of 40–60 °C for eleven days, and the half-life at 70 °C was ten days. Man 58 showed Km and Vmax values of 3.29 mg/mL and 1.76 IU/mL respectively, with locust bean gum as a substrate. It was mostly activated by FeSO4 and CoCl2 and inhibited by MgSO4, FeCl3, CuSO4, MgCl2, ZnCl2, ZnSO4, CaCl2, CuCl2, KCl and ethylenediaminetetraacetic acid (EDTA. Phenolic compounds did not inhibit the enzyme. On the other hand, auto-hydrolysis liquor showed an inhibitory effect on Man 58 activity.

  9. Effect of steam treatment of alperujo on the composition, enzymatic saccharification, and in vitro digestibility of alperujo. (United States)

    Rodríguez, Guillermo; Rodríguez, Rocío; Jiménez, Ana; Guillén, Rafael; Fernandez-Bolaños, Juan


    The solid waste from two-phase olive oil extraction or "alperujo" was submitted to steam treatment at high pressure or temperature, 200 degrees C for 5 min, in the presence and absence of mild acid catalyst. This treatment made easier the separation of the solid and liquid fractions. Besides the recovery of certain valuable components from the liquid fraction (the antioxidant hydroxytyrosol, low molecular weight oligosaccharides, glucose, mannitol, etc.), the major components of the solid residue could be also exploited. In this study, changes in composition of alperujo due to steam treatment were determined. The process reduced appreciably the hemicellulose concentrations (75-88%), removed a substantial portion of Klason lignin and protein (50%), and led to an extensive solubilization of alperujo (55-67%). Cellulose was very resistant to autohydrolysis and acid-catalyzed hydrolysis, so the solid residue was enriched in fat (13-18 g/100 g of dry steam-treated alperujo) and cellulose (15-25 g/100 g of dry and defatted steam-treated alperujo). The steam-treated material can be efficiently saccharified with commercial cellulase. The best hydrolysis yields were attained, up to 80%, when the treated material was post-treated with NaOH. The possibility of using this steam-treated alperujo in animal feeding was evaluated by an in vitro digestibility test, using the pepsin-cellulase method. The treatment affected positively the nutritional characteristics of alperujo with an increase in its in vitro (dry and organic matter) digestibility (8-10% higher than untreated material). In vitro digestibility and cellulose accessibility to enzymatic hydrolysis were improved by the alkali post-treatment.

  10. DOEGO85004_1: Final Non-proprietary Technical Report, Generating Process and Economic Data for Preliminary Design of PureVision Biorefineries DOEGO85004_2: One Original Final Proprietary Technical Report to be mailed to DOE Golden.

    Energy Technology Data Exchange (ETDEWEB)

    Kadam, Kiran L., Ph.D; Lehrburger, Ed


    The overall objective of the project was to define a two-stage reactive fractionation process for converting corn stover into a solid cellulose stream and two liquid streams containing mostly hemicellulosic sugars and lignin, respectively. Toward this goal, biomass fractionation was conducted using a small continuous pilot unit with a nominal capacity of 100 pounds per day of dry biomass to generate performance data using primarily corn stover as feedstock. In the course of the program, the PureVision process was optimized for efficient hemicellulose hydrolysis in the first stage employing autohydrolysis and delignification in the second stage using sodium hydroxide as a catalyst. The remaining cellulose was deemed to be an excellent substrate for producing fermentation sugars, requiring 40% less enzymes for hydrolysis than conventional pretreatment systems using dilute acid. The fractionated cellulose was also determined to have potential higher-value applications as a pulp product. The lignin coproduct was determined to be substantially lower in molecular weight (MW) compared to lignins produced in the kraft or sulfite pulping processes. This low-MW lignin can be used as a feed and concrete binder and as an intermediate for producing a range of high-value products including phenolic resins. This research adds to the understanding of the biomass conversion area in that a new process was developed in the true spirit of biorefineries. The work completed successfully demonstrated the technical effectiveness of the process at the pilot level indicating the technology is ready to advance to a 2–3 ton per day scale. No technical showstoppers are anticipated in scaling up the PureVision fractionation process to commercial scale. Also, economic feasibility of using the PureVision process in a commercial-scale biorefinery was investigated and the minimum ethanol selling price for the PureVision process was calculated to be $0.94/gal ethanol vs. $1.07/gal ethanol for the

  11. 生物质预处理对半纤维素提取及后续CTMP制浆的影响%Effects of Biomass Pretreatment on the Extraction of Hemicelluloses and the Pulp Quality of the Subsequent CTMP

    Institute of Scientific and Technical Information of China (English)

    侯庆喜; 马静; 刘苇; 汪洋; 李杨; 刘莉晖; 张金平


    Pretreatment of the raw material before CTMP(Chemi-thermomechanical Pulp)pulping was performed,in order to make full use of biomass resources and produce value-added products,without lowering the pulp quality.Different pre-extraction methods,such as autohydrolysis,acid and alkali pre-extractions,were used for the pretreatment to study the ef-fects of pre-extraction with various severities on the pulp quality of the following CTMP(i.e.,the comprehensive variablesof the pretreatment temperature and time).The results showed that,as the condition aggravated continually,the yield of the hydrolyzed chips decreased and the amount of the dissolved hemicelluloses increased.The contents of holocellulose, pentosan and acid soluble lignin in the hydrolyzed chips decreased dramatically with the increase of the pretreatment severity.The pretreatment shortened the enzymatic hydrolysis time and improved the conversion of glucose of wheat straw.Compared with the original wood chips,the hydrolyzed chips had not only a lower pressurized refining energy con-sumption but also a higher energy saving in PFI refining.In addition,the CTMP made of hydrolyzed chips had a higher ten-sile index and an enhanced tear index.%在化学热磨机械浆(CTMP)制浆前对原料进行预处理,旨在保证浆料质量的前提下,实现生物质资源的充分和高效利用。采用自水解、酸法、碱法不同预处理方式对生物质进行预处理,通过改变预处理强度因子(温度和时间的综合变量),考察预抽提效果及 CTMP 成浆质量。研究结果表明:随着预处理条件的不断增强,水解木片得率降低,半纤维素溶出量增加,水解后木片中综纤维素、聚戊糖和酸溶木素的含量明显下降,生物酶对麦草葡萄糖的转化率提高。相比未经过预处理的原料,预处理后的原料在制浆过程中压力磨浆能耗和 PFI 打浆能耗分别降低,同时浆张抗张指数和撕裂指数均提高。

  12. 用木材生产生物燃料与纸浆%From Wood to Biofuels and Pulp Production

    Institute of Scientific and Technical Information of China (English)



    A mild alkaline treatment was applied to aspen chips prior to kraft pulping in order .to ex- tract hemicellulose for use as biofuels(bioethanol),the extraction was performed at 90℃, NaOH 1-2M,liguor towood ratio 1-4. It resulted in a recovery of 40-50kg of hemicellulose per ton of chips and yieled the same amount of pulp after subsequent pulping of the extracted chips,as compared to a control cook. The pre-extract process requires careful optimization of the pulping process and allows shorter cooking time and lower chemical charges. The process did not costly pressurized reaction ves- sels. Kraft pulps obtained from per-extracted chips have a slightiy higher cellulose/hemicellulose ratio and demonstrate a small decrease in tensile index(10%), but improved brightness and shive content, while the hemiecllulose yield for this process is low, this problem is outweighed by the fact that pulp properties and pulping yield can be maintained at a high level. The recovered hemicellulose can be con- centrated and isolateed more easily than furfural obtained by autohydrolysis or dilute acid treatment.%杨木木片硫酸盐制浆前,进行缓和的碱抽提处理,抽提出半纤维素用作生物燃料(生物乙醇),在温度90℃,NaOH1-2M,液比1:4条件下进行碱处理,不需要高压设备,每吨木片得到半纤维素40-50kg,经碱抽提后木片进行硫酸盐蒸煮,与未经碱抽提木片参照对比,纸浆得率基本相同,但是需要很好地控制碱抽提与硫酸盐蒸煮工艺条件,能缩短蒸煮时间和节省化学品用量。碱预抽提木片得到的硫酸盐纸浆中纤维素/半纤维素的比率稍高,导致纸浆的抗张指数稍有降低(约10%),但是纸浆白度较高且筛渣含量低,为使硫酸盐纸浆的质量和得率保持较高水平,采用缓和的碱预抽提,使半纤维素得率较低,而回收的半纤维素的浓缩和离析比木片自水解或稀酸水解回收糠醛更加容易。

  13. Woody Components and Enzymatic Hydrolysis Property of Tamarix ramosissima under Various Intensity of Steam Explosion%蒸汽爆破预处理对红柳木质组分及酶解性能的影响

    Institute of Scientific and Technical Information of China (English)

    徐红; 徐勇; 勇强; 余世袁


    以红柳为材料研究蒸汽爆破预处理强度系数IgR对木质组分和纤维素酶水解性能的影响.结果表明:蒸汽爆破处理对红柳中纤维素和木质素含量的影响并不显著,但是它可以有效破坏红柳的天然物理结构,并且导致大部分半纤维素(木聚糖)产生自水解反应生成单糖和低聚糖溶出,同时产生乙酸、甲酸和糠醛等小分子降解产物.基于纤维素回收率和纤维素酶水解得率分析,在蒸汽爆破强度系数达到4.239时(爆破温度210℃和保温时间10 min)对红柳的预处理效果最佳,汽爆物料中纤维素的含量可达到52.4%,残余木聚糖含量仅为2.01%,并生成0.76%甲酸和3.17%乙酸.采用每克纤维素20.0 FPIU的纤维素酶用量水解5%(w/w)该汽爆红柳物料48 h,纤维素酶水解得率可达到86.6%(未处理的原料仅为15.5%).这表明无化学品添加的蒸汽爆破是适于红柳糖化及生物炼制的一种有效的预处理方法.%It' s essential and important to carry out research on the Tamarix ramosissima high-valued biorefining for promoting national land afforestation, ecological construction and agricultural income as Tamarix ramosissima plant is a kind of aboundant lignocellulosic resources in western China. In this study effects of steam explosion intensity (lgR) on the woody components and cellulose enzymatic hydrolysis performance of Tamarix ramosissima were presented during steam explosion pretreatment( SEP) . The result showed that SEP hardly changed the contents of cellulose and sulfuric acid insoluble lignin in Tamarix ramosissima, however, it could break effectively the native structure of Tamarix ramosissima and promote most xylan to degrade into xylose by its auto-hydrolysis, in which some small molecule derivates came together, such as acetic acid, formic, furfural and so on. In view of the recovery ratio and the enzyme hydrolysis yield of cellulose in Tamarix ramosissima, maximum glucose yields upon

  14. Biorefinery Technologies for Biomass Conversion Into Chemicals and Fuels Towards Zero Emissions (Review) / Nulles Emisiju Princips Biomasas Konversijas Tehnoloģijās Aizstājot Fosilos Resursus (Pārskata Raksts) (United States)

    Gravitis, J.; Abolins, J.


    Exhausting of world resources, increasing pollution, and climate change are compelling the shift of the world economy from continuous growth to a kind of economy based on integration of technologies into zero emissions production systems. Transition from non-renewable fossil resources to renewable resources provided by solar radiation and the current processes in biosphere is seen in the bio-refinery approach - replacing crude oil refineries by biomass refineries. Biotechnology and nano-technologies are getting accepted as important players along with conventional biomass refinery technologies. Systems design is a significant element in the integration of bio-refinery technologies in clusters. A number of case-studies, steam explosion auto-hydrolysis (SEA) in particular, are reviewed to demonstrate conversion of biomass into value-added chemicals and fuels. Analysis of energy flows is made as part of modelling the SEA processes, the eMergy (energy memory) approach and sustainability indices being applied to assess environmental impacts. Resursu izsīkums, vides piesārņojums un globāla mēroga klimatiskās izmaiņas ir civilizācijas izdzīvošanai būtiski faktori, kas virza pasaules ekonomikas pārmaiņas, atsakoties no nepārtrauktas izaugsmes idejas par labu tādai ekonomikai, kas balstās uz atjaunojošamies resursiem un dažādu tehnoloģiju integrācijemisiju principam atbilstošās ražošanas sistēmās. Saules radiācijas ierosinātajos planētas biosfērā notiekošajos procesos radīto organisko vielu pārstrādes kompleksi, kas operē ievērojot sabalansētu nulles emisiju principu, tiek uzlūkoti kā tās ekonomiskās (ražošanas) struktūras, kurām jānodrošina pāreja uz atjaunojošos resursu izmantošanu, aizstājot esošās fosilo resursu (naftas, ogļu) pārstrādes rūpnīcas. Līdzās jau apgūtajām biomasas rafinēšanas tehnoloģijām svarīga un pieaugoša loma ekonomiskās sistēmas resursu bāzes nomaiņā ir bio- un nanotehnolo