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Sample records for autohydrolysis

  1. Autohydrolysis Pretreatment of Lignocellulosic Biomass for Bioethanol Production

    Science.gov (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

  2. EFFECT OF OZONE AND AUTOHYDROLYSIS PRETREATMENTS ON ENZYMATIC DIGESTIBILITY OF COASTAL BERMUDA GRASS

    Directory of Open Access Journals (Sweden)

    Jung Myoung Lee

    2010-04-01

    Full Text Available Coastal Bermuda grass (CBG has been shown to have potential as a biomass feedstock for sugar production. In this study, the effectiveness of ozone pretreatment for CBG to improve the sugar recovery via enzyme hydrolysis was investigated. Raw CBG and autohydrolysis-treated CBG were pretreated with ozone at ozone consumption of 1.8 to 26.4 % (w/w at room temperature. Lignin degradation and hemicellulose solubilization increased with increased ozone consumption. At 26.4% ozone consumption by weight on CBG the amount of lignin in the CBG was reduced by 34%. Autohydrolysis of CBG increased the reactivity of cellulose, hemicellulose, and lignin with ozone. The maximum total sugar recovery after enzymatic hydrolysis was 32% for a 14.0% consumption of ozone on raw CBG. For CBG samples pretreated with autohydrolysis followed by a 3.1% ozone consumption pretreatment the maximum total sugar recovery after enzyme hydrolysis was 40.1%. Autohydrolysis pretreatment followed by enzyme hydrolysis yielded a 36.4% sugar recovery, indicating that the application and benefits of ozone after autohydrolysis with the conditions studied herein are marginally better than autohydrolysis alone.

  3. Biorefinery valorization of autohydrolysis wheat straw hemicellulose to be applied in a polymer-blend film

    OpenAIRE

    Ruiz, Héctor A.; Cerqueira, M. A.; Ruíz, Héctor A.; Rodríguez-Jasso, Rosa María; Vicente, A.A.; J. A. Teixeira

    2013-01-01

    The aims of this study were the extraction of hemicellulose from wheat straw (WS) and its utilization in the reinforcement of a κ-carrageenan/locust bean gum (κ-car/LBG) polymeric blend films (PBFs). WS hemicellulose extraction was performed under autohydrolysis process and hemicellulose extracted (HE) under optimum condition was used in PBFs. PBFs were prepared varying different proportions of HE into the κ-car/LBG film-forming solutions. Barrier properties (water vapor permeability, WVP), m...

  4. Understanding of pH value and its effect on autohydrolysis pretreatment prior to poplar chemi-thermomechanical pulping.

    Science.gov (United States)

    Liu, Lihui; Liu, Wei; Hou, Qingxi; Chen, Junwei; Xu, Ningpan

    2015-11-01

    Autohydrolysis pretreatment with different severity factors was performed on poplar chips prior to chemi-thermomechanical pulping (CTMP) in order to investigate the change in pH value and its effect on the autohydrolysis pretreatment. The results showed that the dissolution amount of acetic acid increased with raising the severity factor of the pretreatment and declining the size of poplar chips, respectively. Besides, a logarithmic relationship between the amount of acetic acid released in the autohydrolysis liquor (AHL) and pH value of the AHL was observed. The amounts of glucose and xylose (including those in the form of monomers, oligomers, and polysaccharides) as well as furfural and hydroxymethylfurfural (HMF) also depended on the pH value of the AHL to some extent. PMID:26313534

  5. XYLO-OLIGOSACCHARIDES PRODUCTION BY AUTOHYDROLYSIS OF CORN FIBER SEPARATED FROM DDGS

    Directory of Open Access Journals (Sweden)

    Aditya Samala,

    2012-05-01

    Full Text Available Xylo-oligosaccharides (XOS are reported to have beneficial health properties, and they are considered to be functional food ingredients. Corn fiber separated from distillers dried grains with solubles (DDGS could be a valuable feedstock for XOS production. The objective of this study was to determine the efficacy for autohydrolysis to produce XOS using fiber separated from DDGS and to determine the optimum temperature for XOS production. Corn fiber was treated with deionized water in a Parr-reactor, at temperatures ranging from 140 to 220 °C to produce XOS. The maximum total yield of XOS in the solution was 18.6 wt% of the corn fiber at 180 °C.

  6. Comparison, modeling and simulation of enzymatic saccharification on olive tree biomass under dilute acid and autohydrolysis pretreatment

    OpenAIRE

    Ruíz, Héctor A.; E. Ruiz; de Castro, E.

    2012-01-01

    Bioethanol can be produced from pretreated olive tree biomass (OTB) followed by enzymatic hydrolysis and fermentation. In order to obtain high overall ethanol yield, the pretreatment step should improve the accessibility of cellulose to hydrolytic enzymes. The modeling and simulation of enzymatic hydrolysis pretreated solids obtained by diluted acid (DA) and autohydrolysis (AH) were studied. The assumptions of the first and second order model of cellulase deactivation are: 1) a single combine...

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

    Science.gov (United States)

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

    2016-01-01

    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.

    Science.gov (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

    2016-07-01

    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. PMID:27017132

  9. Ethanol production from olive prunings by autohydrolysis and fermentation with Candida tropicalis

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Martin, Juan Francisco; Bravo, Vicente [Department of Chemical Engineering, University of Granada, Campus Universitario de Fuentenueva, 18071 Granada (Spain); Cuevas, Manuel; Sanchez, Sebastian [Department of Chemical, Environmental and Materials Engineering, University of Jaen, Campus Las Lagunillas, 23071 Jaen (Spain)

    2010-07-15

    Hydrolysates from olive prunings (a renewable, low-cost, easily available, agricultural residue) were fermented with the unconventional yeast Candida tropicalis NBRC 0618 to produce not only ethanol fuel but also xylitol as a by-product, which adds value to the economic viability of the bioprocess. Autohydrolysis took place at 200 C in a stirred stainless-steel tank reactor. The influence of the solid/liquid ratio in the reactor was studied. Fermentation experiments were conducted in a batch-culture reactor at a temperature of 30 C, a stirring rate of 500 rpm and pH values of between 5.0 and 6.5. Under the operating conditions tested the highest yields of ethanol and xylitol were obtained with the hydrolysate fermented at pH 5.0 and solely the airflow that entered via the stirring vortex. Under these conditions, the instantaneous ethanol yield was 0.44 g g{sup -1} and the overall xylitol yield 0.13 g g{sup -1}. (author)

  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.

    2015-01-01

    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)

    OpenAIRE

    Mayra Lizett González-Félix; Martin Perez-Velazquez; Josafat Marina Ezquerra-Brauer; Lorena Bringas-Alvarado; Anabel Sánchez-Sánchez; Wilfrido Torres-Arreola

    2014-01-01

    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 hydrolys...

  12. 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

    Directory of Open Access Journals (Sweden)

    Mayra Lizett González-Félix

    2014-09-01

    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.

  13. Interactions between Cellulolytic Enzymes with Native, Autohydrolysis, and Technical Lignins and the Effect of a Polysorbate Amphiphile in Reducing Nonproductive Binding.

    Science.gov (United States)

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

    2015-12-14

    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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...... treatment of wildtype and transgenic extracts from dry stems showed a decrease in the molecular weight of xylans from transgenic stems....

  15. Effects of Eucalyptus globulus Wood Autohydrolysis Conditions on the Reaction Products

    NARCIS (Netherlands)

    Garrote, G.; Kabel, M.A.; Schols, H.A.; Falque, E.; Domingues, H.; Parajo, J.C.

    2007-01-01

    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, oligosacchar

  16. Production of xylo-oligosaccharides from Miscanthus x giganteus by autohydrolysis

    NARCIS (Netherlands)

    Ligero, P.; Kolk, van der J.C.; Vega, de A.; Dam, van J.E.G.

    2011-01-01

    Xylo-oligosaccharides were obtained from Miscanthus x giganteus. The process was designed as a biorefinery scheme, which seeks the separation of the three main components: cellulose, hemicelluloses, and lignin. To extract the hemicelluloses, particularly xylans, in an efficient way, Miscanthus was s

  17. Combined alkali and hydrothermal pretreatments for oat straw valorization within a biorefinery concept.

    Science.gov (United States)

    Romaní, Aloia; Tomaz, Pablo D; Garrote, Gil; Teixeira, José A; Domingues, Lucília

    2016-11-01

    The aim of this work was the evaluation of lime pretreatment combined or not with previous step of autohydrolysis for oat straw valorization. Under selected conditions of lime pretreatment, 96% of glucan and 77% of xylan were recovered and 42% of delignification was achieved. Xylose fermentation to ethanol by metabolic engineered Saccharomyces cerevisiae (MEC1133) strain improved the ethanol production by 22% achieving 41g/L. Alternatively, first step of autohydrolysis (S0=4.22) allowed a high oligosaccharides recovery (68%) and subsequent lime pretreatment attained a 57% of delignification and 99% of glucan to glucose conversion. Oat straw processed by autohydrolysis and lime pretreatment reached the maximal ethanol concentration (50g/L). Both strategies led to oat straw valorization into bioethanol, oligosaccharides and lignin indicating that these pretreatments are adequate as a first stage within an oat straw biorefinery. PMID:27591518

  18. Kinetic study of biomass hydrolysis under high pressure conditions

    OpenAIRE

    Relvas, Frederico Miguel Horta de Albuquerque Moura

    2014-01-01

    This study was focused on the kinetics of lignocellulosic biomass pre-treatment, in particular CO2-assisted autohydrolysis. The temperature was fixed at 180 ºC, varying pressure from 0 (CO2-free autohydrolysis), 20, 35 to 50 bar. For every pressure, a set of isothermal reactions was performed for various reaction times from 0 and 45 minutes. The pre-treatment resulted in a liquid, solid and gas phases, which were analyzed by HPLC. The liquid phase is essentially composed by sugars both in ...

  19. Prebiotic xylo-oligosaccharides as high-value co-products on an integrated biorefinery approach from lignocellulosic feedstock

    OpenAIRE

    Moura, Patrícia; Carvalheiro, Florbela; Esteves, M. P.; Gírio, Francisco M.

    2008-01-01

    The present work proposes the production of prebiotic xylo-oligosaccharides (XOS) as high-value co-products of the Lignocellulose Feedstock Biorefinery concept, foreseeing potential applications on food, feed and nutraceutical industries. Autohydrolysis was used to selectively solubilise the hemicellulosic fraction of several xylan-rich, widely available, agricultural, agro-industrial and forestry by-products: corn cobs, brewery’s spent grain and Eucalyptus wood chips. The soluble hemicellulo...

  20. ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

    OpenAIRE

    Carlos Vila; Javier Romero; José Luis Francisco,; Valentín Santos,; Juan Carlos Parajó

    2012-01-01

    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 pressurize...

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

    OpenAIRE

    Cristian-Teodor BURUIANĂ; Camelia VIZIREANU

    2014-01-01

    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 t...

  2. Co-production of electricity and ethanol, process economics of value prior combustion

    International Nuclear Information System (INIS)

    Highlights: ► Economics of producing cellulosic ethanol and bio-power in the same facility using an autohydrolysis process. ► Feedstock considerably affect the economics of the biorefinery facility. ► Lower moisture content improves financial performance of the bio-power business. - Abstract: A process economic analysis of co-producing bioethanol and electricity (value prior to combustion) from mixed southern hardwood and southern yellow pine is presented. Bioethanol is produced by extracting carbohydrates from wood via autohydrolysis, membrane separation of byproducts, enzymatic hydrolysis of extracted oligomers and fermentation to ethanol. The residual solids after autohydrolysis are pressed and burned in a power boiler to generate steam and electricity. A base case scenario of biomass combustion to produce electricity is presented as a reference to understand the basics of bio-power generation economics. For the base case, minimum electricity revenue of $70–$96/MWh must be realized to achieve a 6–12% internal rate of return. In the alternative co-production cases, the ethanol facility is treated as a separate business entity that purchases power and steam from the biomass power plant. Minimum ethanol revenue required to achieve a 12% internal rate of return was estimated to be $0.84–$1.05/l for hardwood and $0.74–$0.85/l for softwood. Based on current market conditions and an assumed future ethanol selling price of $0.65/l, the co-production of cellulosic bioethanol and power does not produce financeable returns. A risk analysis indicates that there is a probability of 26.6% to achieve an internal rate of return equal or higher than 12%. It is suggested that focus be placed on improving yield and reducing CAPEX before this technology can be applied commercially. This modeling approach is a robust method to evaluate economic feasibility of integrated production of bio-power and other products based on extracted hemicellulose.

  3. Effect of steam pretreatment on oil palm empty fruit bunch for the production of sugars

    International Nuclear Information System (INIS)

    Lignocellulose into fuel ethanol is the most feasible conversion route strategy in terms of sustainability. Oil palm empty fruit bunch (EFB) generated from palm oil production is a huge source of cellulosic material and represents a cheap renewable feedstock which awaits further commercial exploitation. The purpose of this study was to investigate the feasibility of using steam at 0.28 MPa and 140 °C generated from the palm oil mill boiler as a pretreatment to enhance the digestibility of EFB for sugars production. The effects of steam pretreatment or autohydrolysis on chemical composition changes, polysaccharide conversion, sugar production and morphology alterations of four different types of EFB namely fresh EFB (EFB1), sterilized EFB (EFB2), shredded EFB (EFB3) and ground EFB (EFB4) were evaluated. In this study, the effects of steam pretreatment showed major alterations in the morphology of EFB as observed under the scanning electron microscope. Steam pretreated EFB2 was found to have the highest total conversion of 30% to sugars with 209 g kg−1 EFB. This production was 10.5 fold higher than for EFB1 and 1.6 fold and 1.7 fold higher than EFB3 and EFB4, respectively. The results suggested that pretreatment of EFB by autohydrolysis using steam from the mill boiler could be considered as being a suitable pretreatment process for the production of sugars. These sugars can be utilized as potential substrates for the production of various products such as fuel ethanol. -- Highlights: ► We investigate the feasibility of steam pretreatment to enhance digestibility of EFB. ► Steam pretreatment increased sugars to 3.4 fold and caused major alteration in EFB morphology under SEM. ► Autohydrolysis which does not require the addition of chemicals is an attractive pretreatment approach to EFB.

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

    Directory of Open Access Journals (Sweden)

    Stanislav D. Anastyuk

    2014-01-01

    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.

  5. Impact of the lignin structure of three lignocellulosic feedstocks on their organosolv delignification. Effect of carbonium ion scavengers

    International Nuclear Information System (INIS)

    Effect of autohydrolysis and aromatic scavengers on delignification patterns were evaluated using miscanthus (MxG), empty palm fruit bunch (EFB) and typha grass residue as feedstocks. Autohydrolysis was carried out without naphthol and in the presence of naphthol followed by delignification by ethanol organosolv process. Despite their close chemical composition, the three feedstocks demonstrated quite different patterns of delignification under the same condition of pretreatment. Nuclear magnetic resonance (NMR) spectroscopic characterization of ethanol organosolv lignins (EOLs) extracted from the three feedstocks revealed information concerning syringyl, guaiacyl and hydroxyphenyl content (S/G/H ratios) which underpinned the differences among the feedstock behavior. The (S + H)/G ratios for MxG, EFB and typha were determined as 1.27, 2.33 and 2.70 respectively. The major cause of difference in behavior of feedstock during the pretreatment process was attributed to the variation in lignin composition. A good relationship was observed between S/G ratio and the scavenging effect of 2-naphthol. The effect of four additional aromatic scavengers viz. p-cresol, o-cresol, hydroquinone and dihydroxyanthraquinone (DHAQ) tested in miscanthus demonstrated a significant enhancement on delignification; the effect of p-cresol and DHAQ was tantamount to that of naphthol. Cellulolytic enzyme lignin (CEL) extracted from typha grass was also subjected to 13C NMR characterization in order to obtain a more complete picture of typha lignin. Comparison of NMR spectra of CEL and EOL from TC was performed for determining the processing effect in lignin structure. -- Highlights: ► Effect of autohydrolysis and aromatic scavengers on delignification patterns were evaluated. ► Ethanol organosolv lignins and Cellulolytic Enzyme Lignin extracted from typha were characterized. ► A correlation was observed between S + H/G ratio and the effect of aromatic scavengers

  6. Production and purification of xylooligosaccharides from oil palm empty fruit bunch fibre by a non-isothermal process

    OpenAIRE

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

    2014-01-01

    Oil palm empty fruit bunches (OPEFB) fibre, a by-product generated from non-woody, tropical perennial oil palm crop was evaluated for xylooligosaccharides (XOS) production. Samples of OPEFB fibre were subjected to non-isothermal autohydrolysis treatment using a temperature range from 150 to 220 ºC. The highest XOS concentration, 17.6 g/L which relayed from solubilisation of 63 g/100 g xylan was achieved at 210 ºC and there was a minimum amount of xylose and furfural being produced. The ch...

  7. ON THE RECOVERY OF HEMICELLULOSE BEFORE KRAFT PULPING

    Directory of Open Access Journals (Sweden)

    Carlos Vila,

    2012-07-01

    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.

  8. Effect of hemicellulose liquid phase on the enzymatic hydrolysis of autohydrolyzed Eucalyptus globulus wood

    OpenAIRE

    Romaní, Aloia; Ruíz, Héctor A.; Pereira, Francisco B.; Domingues, Lucília; Teixeira, J. A.

    2014-01-01

    In this work, Eucalyptus globulus wood was pretreated under non-isothermal autohydrolysis process at 210, 220, and 230 °C, obtaining a pretreated solid with high cellulose content and a hemicellulosic liquid phase (HLP) containing mainly xylose, acetic acid, furfural, xylooligosaccharides, and phenolic compounds. The maximum concentration of xylooligosaccharides (8.97 g/L) and phenolic compounds (2.66 g/L) was obtained at 210 and 230 °C, respectively. To evaluate the effect of HLP addition on...

  9. PURIFICATION OF HARDWOOD-DERIVED AUTOHYDROLYSATES

    OpenAIRE

    Joni Tapani Lehto,; Raimo Juhani Alén

    2012-01-01

    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-(hydroxymethyl)furfural) could be removed, whereas in th...

  10. SODA-AQ PULPING OF PAULOWNIA WOOD AFTER HYDROLYSIS TREATMENT

    Directory of Open Access Journals (Sweden)

    Juan Carlos García

    2011-04-01

    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.

  11. Assessment of suitability of vine shoots for hemicellulosic oligosaccharides production through aqueous processing.

    Science.gov (United States)

    Dávila, Izaskun; Gordobil, Oihana; Labidi, Jalel; Gullón, Patricia

    2016-07-01

    Vine shoots were subjected to non-isothermal aqueous processing. A range of severities (S0) from 3.20 to 4.65 was assayed and their effects in terms of solubilization, composition, molar mass distribution, structural characterization and thermal stability of the liquors were studied using HPLC, HPSEC, TGA and FTIR. The spent solids were characterized by HPLC and FTIR. When autohydrolysis was carried out at S0=4.01, the substrate solubilization achieved a 38.7% of the raw material and 83.1% of the initial xylan was converted into xylooligosaccharides (XOS). The amount of TOS (total oligosaccharides) in the hydrolysates was 28.4g/L while the other non volatile compounds (ONVC) were 0.08g/g NVC. The spent solid from the treatment at S0=4.01 was composed about 90% of cellulose and lignin. Therefore, it can be concluded that autohydrolysis is a suitable pretreatment of vine shoots such as a first stage of a biomass refinery. PMID:27054881

  12. Development of Geothermally Assisted Process for Production of Liquid Fuels and Chemicals from Wheat Straw

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, V.G.; Linden, J.C.; Moreira, A.R.; Lenz, T.G.

    1981-06-01

    Recently there has been much interest in developing processes for producing liquid fuels from renewable resources. The most logical long term approach in terms of economics derives the carbohydrate substrate for fermentation from the hydrolysis of cellulosic crop and forest residues rather than from grains or other high grade food materials (1,2). Since the presence of lignin is the main barrier to the hydrolysis of cellulose from lignocellulosic materials, delignification processes developed by the wood pulping industry have been considered as possible prehydrolysis treatments. The delignification process under study in our laboratory is envisioned as a synthesis of two recently developed pulping processes. In the first step, called autohydrolysis, hot water is used directly to solubilize hemicellulose and to depolymerize lignin (3). Then, in a second step known as organosolv pulping (4), the autohydrolyzed material is extracted with aqueous alcohol. A s shown in Figure 1, this process can separate the original lignocellulosic material into three streams--hemicellulose in water, lignin in aqueous alcohol, and a cellulose pulp. Without further mechanical milling, delignified cellulose can be enzymatically hydrolyzed at 45-50 C to greater than 80% theoretical yield of glucose using fungal cellulases (5, 6). The resulting glucose syrup can then be fermented by yeast to produce ethanol or by selected bacteria to produce acetone and butanol or acetic and propionic acids (7). One objection to such a process, however, is the large energy input that is required. In order to extend our supplies of liquid fuels and chemicals, it is important that the use of fossil fuels in any lignocellulosic conversion process be minimized. The direct use of geothermal hot water in carrying out the autohydrolysis and extraction operations, therefore, seems especially attractive. On the one hand, it facilitates the conversion of non-food biomass to fuels and chemicals without wasting fossil

  13. Production and purification of xylooligosaccharides from oil palm empty fruit bunch fibre by a non-isothermal process.

    Science.gov (United States)

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

    2014-01-01

    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. PMID:24275261

  14. Energy from Biomass for Conversion of Biomass

    Science.gov (United States)

    Abolins, J.; Gravitis, J.

    2009-01-01

    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.

  15. PURIFICATION OF HARDWOOD-DERIVED AUTOHYDROLYSATES

    Directory of Open Access Journals (Sweden)

    Joni Tapani Lehto,

    2012-02-01

    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.

  16. CHEMICAL VALORIZATION OF AGRICULTURAL BY-PRODUCTS: ISOLATION AND CHARACTERIZATION OF XYLAN-BASED ANTIOXIDANTS FROM ALMOND SHELL BIOMASS

    Directory of Open Access Journals (Sweden)

    Anna Ebringerová

    2008-02-01

    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.

  17. Method and apparatus for treating a cellulosic feedstock

    Science.gov (United States)

    Nguyen, Quang A.; Burke, Murray J.; Hillier, Sunalie N.

    2015-09-08

    Methods and apparatus for treating, pre-treating, preparing and conveying a cellulosic feedstock, such as for ethanol production, are disclosed. More specifically, the invention relates to methods and apparatus for treating a cellulosic feedstock by mixing and heating the cellulosic feedstock and/or by moistening and heating the cellulosic feedstock. The invention also relates to a holding tank, and a method of utilizing the holding tank whereby bridging may be reduced or eliminated and may result in a product stream from autohydrolysis or hydrolysis having an improved yield. The invention further relates to methods and apparatus for obtaining and conveying a cellulosic feedstock, which may be used for the subsequent production of a fermentable sugar stream from the cellulose and hemicellulose in the cellulosic feedstock wherein the fermentable sugar stream may be used for subsequent ethanol production. The invention also relates to a method and apparatus for withdrawing one or more feedstock stream from a holding tank.

  18. Review of pretreatment processes for lignocellulosic ethanol production, and development of an innovative method

    International Nuclear Information System (INIS)

    Biomass pretreatment aims at separating and providing easier access to the main biomass components (cellulose, hemicellulose and lignin), eventually removing lignin, preserving the hemicellulose, reducing the cellulose crystallinity and increasing the porosity of the material. Pretreatment is an essential step towards the development and industrialization of efficient 2nd generation lignocellulosic ethanol processes. The present work reviewed the main options available in pretreatment. Autohydrolysis and steam explosion were then selected for further investigation. Experimental work was carried out on batch scale reactors, using Miscanthus as biomass feedstock: the effects on sugar solubilization and degradation products generation have been examined for each of these two pretreatment systems. A new process using only water and steam as reacting media was then developed, experimentally tested, and results compared to those achieved by the autohydrolysis and steam explosion processes. Products obtained with the new pretreatment contained a lower amount of usual fermentation inhibitor compounds compared to that typically obtained in steam explosion. This result was achieved under operating conditions that at the same time allowed a good xylan yield, preventing degradation of hemicelluloses. The new pretreatment process was also able to act as an equalization step, as the solid material from the pretreatment phase had a similar composition even under different operating conditions. As regards the effect of pretreatment on enzymatic hydrolysis, the new process achieved yields similar to steam explosion on glucans: however, this was obtained reducing the formation of degradation products from sugars, mainly from C5 sugars. These results made the proposed pretreatment system suitable for further development and industrialization on pilot and industrial scale.

  19. Novel process for the coproduction of xylo-oligosaccharides, fermentable sugars, and lignosulfonates from hardwood.

    Science.gov (United States)

    Huang, Caoxing; Jeuck, Ben; Du, Jing; Yong, Qiang; Chang, Hou-Min; Jameel, Hasan; Phillips, Richard

    2016-11-01

    Many biorefineries have not been commercialized due to poor economic returns from final products. In this work, a novel process has been developed to coproduce valuable sugars, xylo-oligosaccharides, and lignosulfonates from hardwood. The modified process includes a mild autohydrolysis pretreatment, which enables for the recovery of the xylo-oligosaccharides in auto-hydrolysate. Following enzymatic hydrolysis, the residue is sulfomethylated to produce lignosulfonates. Recycling the sulfomethylation residues increased both the glucan recovery and lignosulfonate production. The glucose recovery was increased from 81.7% to 87.9%. Steady state simulation using 100g of hardwood produced 46.7g sugars, 5.9g xylo-oligosaccharides, and 25.7g lignosulfonates, which were significantly higher than that produced from the no-recycling process with 39.1g sugars, 5.9g xylo-oligosaccharides, and 15.0g lignosulfonates. The results indicate that this novel biorefinery process can improve the production of fermentable sugars and lignosulfonate from hardwood as compared to a conventional biorefinery process. PMID:27543951

  20. Feasibility study for anaerobic digestion of agricultural crop residues. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1979-10-01

    This study provides cost estimates for the pretreatment/digestion of crop residues to fuel gas. Agricultural statistics indicate 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 sheat straw, corn stover, and rice straw for small farm, cooperative, and industrial scales. 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. 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.

  1. 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.

    1979-07-31

    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.

  2. Evaluation of hydrogen and methane production from sugarcane bagasse hemicellulose hydrolysates by two-stage anaerobic digestion process.

    Science.gov (United States)

    Baêta, Bruno Eduardo Lobo; Lima, Diego Roberto Sousa; Filho, José Gabriel Balena; Adarme, Oscar Fernando Herrera; Gurgel, Leandro Vinícius Alves; Aquino, Sérgio Francisco de

    2016-10-01

    This study aimed at optimizing the net energy recovery from hydrogen and methane production through anaerobic digestion of the hemicellulose hydrolysate (HH) obtained by desirable conditions (DC) of autohydrolysis pretreatment (AH) of sugarcane bagasse (SB). Anaerobic digestion was carried out in a two-stage (acidogenic-methanogenic) batch system where the acidogenic phase worked as a hydrolysis and biodetoxification step. This allowed the utilization of more severe AH pretreatment conditions, i.e. T=178.6°C and t=55min (DC3) and T=182.9°C and t=40.71min (DC4). Such severe conditions resulted in higher extraction of hemicelluloses from SB (DC1=68.07%, DC2=48.99%, DC3=77.40% and DC4=73.90%), which consequently improved the net energy balance of the proposed process. The estimated energy from the combustion of both biogases (H2 and CH4) accumulated during the two-stage anaerobic digestion of HH generated by DC4 condition was capable of producing a net energy of 3.15MJ·kgSB(-1)dry weight. PMID:27393834

  3. Oligosaccharides and monomeric carbohydrates production from olive tree pruning biomass.

    Science.gov (United States)

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

    2013-04-01

    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. PMID:23499077

  4. Structural characterization and cytotoxic properties of a 4-O-methylglucuronoxylan from castanea sativa. 2. Evidence of a structure-activity relationship.

    Science.gov (United States)

    Barbat, Aline; Gloaguen, Vincent; Moine, Charlotte; Sainte-Catherine, Odile; Kraemer, Michel; Rogniaux, Hélène; Ropartz, David; Krausz, Pierre

    2008-08-01

    Xylans were purified from delignified holocellulose alkaline extracts of Castanea sativa (Spanish chestnut) and Argania spinosa (Argan tree) and their structures analyzed by means of GC of their per-trimethylsilylated methylglycoside derivatives and (1)H NMR spectroscopy. The structures deduced were characteristic of a 4-O-methylglucuronoxylan (MGX) and a homoxylan (HX), respectively, with degrees of polymerization ranging from 182 to 360. In the case of MGX, the regular or random distribution of 4-O-methylglucuronic acid along the xylosyl backbone--determined by MALDI mass spectrometry after autohydrolysis of the polysaccharide--varied and depended both on the botanical source from which they were extracted and on the xylan extraction procedure. The MGX also inhibited in different ways the proliferation as well as the migration and invasion capability of A431 human epidermoid carcinoma cells. These biological properties could be correlated with structural features including values of the degree of polymerization, 4-O-MeGlcA to xylose ratios, and distribution of 4-O-MeGlcA along the xylosyl backbone, giving evidence of a defined structure-activity relationship. PMID:18646856

  5. Kinetics of enzyme-catalyzed hydrolysis of steam-exploded sugarcane bagasse.

    Science.gov (United States)

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

    2013-11-01

    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.

  6. Steam explosion pretreatment of triticale (× Triticosecale Wittmack) straw for sugar production.

    Science.gov (United States)

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

    2016-01-25

    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.

  7. Autohydrolysed Tilapia nilotica Fish Viscera as a Peptone Source in Bacteriocin Production.

    Science.gov (United States)

    Deraz, Sahar F; El-Fawal, Gomaa F; Abd-Ellatif, Sawsan A; Khalil, Ashraf A

    2011-06-01

    Fish processing generates large amounts of solid and liquid wastes. Many different by-products have been produced from fish processing wastes. Studies on solubilization of Bolti fish (Tilapia nilotica) viscera by endogenous enzymes at different pHs are described. Hydrolysis reactions were conducted with freshly thawed viscera utilizing an initial temperature gradient and terminated at various time points by heat inactivation of the enzymes. Various peptones obtained from hydrolysed visceral homogenates of Bolti fish residues showed their suitability for promoting the growth of lactic acid bacteria (mainly Lactobacillus sake Lb 706), microorganisms with particularly complex nutritional requirements especially peptidic sources. The assay of several treatments with L. sakei Lb 706, producer of the bacteriocin sakacin A, demonstrated that optimum conditions for biomass and bacteriocin production only imply a brief autohydrolysis at room temperature. The results showed that the Bolti fish hydrolysates gave remarkable results to those found in costly commercial media, specifically recommended for culturing and large-scale production of lactic acid bacteria. PMID:22654160

  8. Production, Purification, and in Vitro Evaluation of the Prebiotic Potential of Arabinoxylooligosaccharides from Brewer's Spent Grain.

    Science.gov (United States)

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

    2015-09-30

    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. PMID:26345203

  9. Extraction of valuable compounds from mangosteen pericarps by hydrothermal assisted sonication

    Science.gov (United States)

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

    2015-12-01

    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.

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

    Directory of Open Access Journals (Sweden)

    Cristian-Teodor BURUIANĂ

    2014-12-01

    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.

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

    Science.gov (United States)

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

    2015-11-01

    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.

  12. Submerged citric acid fermentation on orange peel autohydrolysate.

    Science.gov (United States)

    Rivas, Beatriz; Torrado, Ana; Torre, Paolo; Converti, Attilio; Domínguez, José Manuel

    2008-04-01

    The citrus-processing industry generates in the Mediterranean area huge amounts of orange peel as a byproduct from the industrial extraction of citrus juices. To reduce its environmental impact as well as to provide an extra profit, this residue was investigated in this study as an alternative substrate for the fermentative production of citric acid. Orange peel contained 16.9% soluble sugars, 9.21% cellulose, 10.5% hemicellulose, and 42.5% pectin as the most important components. To get solutions rich in soluble and starchy sugars to be used as a carbon source for citric acid fermentation, this raw material was submitted to autohydrolysis, a process that does not make use of any acidic catalyst. Liquors obtained by this process under optimum conditions (temperature of 130 degrees C and a liquid/solid ratio of 8.0 g/g) contained 38.2 g/L free sugars (8.3 g/L sucrose, 13.7 g/L glucose, and 16.2 g/L fructose) and significant amounts of metals, particularly Mg, Ca, Zn, and K. Without additional nutrients, these liquors were employed for citric acid production by Aspergillus niger CECT 2090 (ATCC 9142, NRRL 599). Addition of calcium carbonate enhanced citric acid production because it prevented progressive acidification of the medium. Moreover, the influence of methanol addition on citric acid formation was investigated. Under the best conditions (40 mL of methanol/kg of medium), an effective conversion of sugars into citric acid was ensured (maximum citric acid concentration of 9.2 g/L, volumetric productivity of 0.128 g/(L.h), and yield of product on consumed sugars of 0.53 g/g), hence demonstrating the potential of orange peel wastes as an alternative raw material for citric acid fermentation. PMID:18321055

  13. Effect of steam treatment of alperujo on the composition, enzymatic saccharification, and in vitro digestibility of alperujo.

    Science.gov (United States)

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

    2007-01-10

    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.

  14. Arsenic toxicity: the effects on plant metabolism

    Directory of Open Access Journals (Sweden)

    Patrick eFinnegan

    2012-06-01

    Full Text Available The two forms inorganic arsenic, arsenate (AsV and arsenite (AsIII, are easily taken up by the cells of the plant root. Once in the cell, AsV can be readily converted to AsIII, the more toxic of the two forms. AsV and AsIII both disrupt plant metabolism, but through distinct mechanisms. AsV is a chemical analogue of phosphate that can disrupt at least some phosphate-dependent aspects of metabolism. AsV can be translocated across cellular membranes by phosphate transport proteins, leading to imbalances in phosphate supply. It can compete with phosphate during phosphorylation reactions, leading to the formation of AsV adducts that are often unstable and short-lived. As an example, the formation and rapid autohydrolysis of AsV-ADP sets in place a futile cycle that uncouples photophosphorylation and oxidative phosphorylation, decreasing the ability of cells to produce ATP and carry out normal metabolism. AsIII is a dithiol reactive compound that binds to and potentially inactivates enzymes containing closely spaced cysteine residues or other sulfhydryl-containing groups. Arsenic exposure generally induces the production of reactive oxygen species that can lead to the production of antioxidant metabolites and numerous enzymes involved in antioxidant defense. Oxidative carbon metabolism, amino acid and protein relationships, and nitrogen and sulfur assimilation pathways are also impacted by As exposure. These effects are reflected in a dramatic restructuring of amino acid pools in Arabidopsis thaliana upon AsV exposure. Readjustment of several metabolic pathways, such as glutathione production, has been shown to lead to increased arsenic tolerance in plants. Species- and cultivar-dependent variation in arsenic sensitivity and the remodeling of metabolite pools that occurs in response to As exposure gives hope that additional metabolic pathways associated with As tolerance will be identified.

  15. 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

    2008-01-17

    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

  16. 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)

    姚光裕

    2012-01-01

    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。

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

    Science.gov (United States)

    Gravitis, J.; Abolins, J.

    2013-10-01

    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