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Sample records for acid pretreatment significantly

  1. Carbonic Acid Pretreatment of Biomass

    SciTech Connect

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  2. Dilute acid and autohydrolysis pretreatment.

    PubMed

    Yang, Bin; Wyman, Charles E

    2009-01-01

    Exposure of cellulosic biomass to temperatures of about 120-210 degrees 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. PMID:19768619

  3. Biomass pretreatment affects Ustilago maydis in producing itaconic acid

    PubMed Central

    2012-01-01

    Background In the last years, the biotechnological production of platform chemicals for fuel components has become a major focus of interest. Although ligno-cellulosic material is considered as suitable feedstock, the almost inevitable pretreatment of this recalcitrant material may interfere with the subsequent fermentation steps. In this study, the fungus Ustilago maydis was used to produce itaconic acid as platform chemical for the synthesis of potential biofuels such as 3-methyltetrahydrofuran. No studies, however, have investigated how pretreatment of ligno-cellulosic biomass precisely influences the subsequent fermentation by U. maydis. Thus, this current study aims to first characterize U. maydis in shake flasks and then to evaluate the influence of three exemplary pretreatment methods on the cultivation and itaconic acid production of this fungus. Cellulose enzymatically hydrolysed in seawater and salt-assisted organic-acid catalysed cellulose were investigated as substrates. Lastly, hydrolysed hemicellulose from fractionated beech wood was applied as substrate. Results U. maydis was characterized on shake flask level regarding its itaconic acid production on glucose. Nitrogen limitation was shown to be a crucial condition for the production of itaconic acid. For itaconic acid concentrations above 25 g/L, a significant product inhibition was observed. Performing experiments that simulated influences of possible pretreatment methods, U. maydis was only slightly affected by high osmolarities up to 3.5 osmol/L as well as of 0.1 M oxalic acid. The production of itaconic acid was achieved on pretreated cellulose in seawater and on the hydrolysed hemicellulosic fraction of pretreated beech wood. Conclusion The fungus U. maydis is a promising producer of itaconic acid, since it grows as single cells (yeast-like) in submerged cultivations and it is extremely robust in high osmotic media and real seawater. Moreover, U. maydis can grow on the hemicellulosic fraction

  4. Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments

    SciTech Connect

    Zhang, Yan; Inouye, Hideyo; Yang, Lin; Himmel, Michael E.; Tucker, Melvin; Makowski, Lee

    2015-02-28

    Cellulose is an attractive candidate as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering experiments have been performed on native and pre-treated maize stover and models of cellulose architecture have been derived from these data. Ultra small-angle, very small-angle and small-angle X-ray scattering (USAXS, VSAXS and SAXS) probe three different levels of architectural scale. USAXS and SAXS have been used to study cellulose at two distinct length scales, modeling the fibrils as ~30 Å diameter rods packed into ~0.14 μm diameter bundles. VSAXS is sensitive to structural features at length scales between these two extremes. Detailed analysis of diffraction patterns from untreated and pretreated maize using cylindrical Guinier plots and the derivatives of these plots reveals the presence of substructures within the ~0.14 μm diameter bundles that correspond to grouping of cellulose approximately 30 nm in diameter. These sub-structures are resilient to dilute acid pretreatments but are sensitive to pretreatment when iron sulfate is added. Lastly, these results provide evidence of the hierarchical arrangement of cellulose at three length scales and the evolution of these arrangements during pre-treatments.

  5. Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments

    SciTech Connect

    Zhang, Yan; Inouye, Hideyo; Yang, Lin; Himmel, Michael E.; Tucker, Melvin; Makowski, Lee

    2015-02-28

    Cellulose can work as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering experiments have been performed on native and pre-treated maize stover and models of cellulose architecture have been derived from these data. Ultra small-angle, very small-angle and small-angle X-ray scattering (USAXS, VSAXS and SAXS) probe three different levels of architectural scale. USAXS and SAXS have been used to study cellulose at two distinct length scales, modeling the fibrils as ~30 Å diameter rods packed into ~0.14 μm diameter bundles. VSAXS is sensitive to structural features at length scales between these two extremes. Detailed analysis of diffraction patterns from untreated and pretreated maize using cylindrical Guinier plots and the derivatives of these plots reveals the presence of substructures within the ~0.14 μm diameter bundles that correspond to grouping of cellulose approximately 30 nm in diameter. These sub-structures are resilient to dilute acid pretreatments but are sensitive to pretreatment when iron sulfate is added. Our results provide evidence of the hierarchical arrangement of cellulose at three length scales and the evolution of these arrangements during pre-treatments.

  6. Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments

    DOE PAGESBeta

    Zhang, Yan; Inouye, Hideyo; Yang, Lin; Himmel, Michael E.; Tucker, Melvin; Makowski, Lee

    2015-02-28

    Cellulose is an attractive candidate as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering experiments have been performed on native and pre-treated maize stover and models of cellulose architecture have been derived from these data. Ultra small-angle, very small-angle and small-angle X-ray scattering (USAXS, VSAXS and SAXS) probe three different levels of architectural scale. USAXS and SAXS have been used to study cellulose atmore » two distinct length scales, modeling the fibrils as ~30 Å diameter rods packed into ~0.14 μm diameter bundles. VSAXS is sensitive to structural features at length scales between these two extremes. Detailed analysis of diffraction patterns from untreated and pretreated maize using cylindrical Guinier plots and the derivatives of these plots reveals the presence of substructures within the ~0.14 μm diameter bundles that correspond to grouping of cellulose approximately 30 nm in diameter. These sub-structures are resilient to dilute acid pretreatments but are sensitive to pretreatment when iron sulfate is added. Lastly, these results provide evidence of the hierarchical arrangement of cellulose at three length scales and the evolution of these arrangements during pre-treatments.« less

  7. Pretreatment of solid carbonaceous material with dicarboxylic aromatic acids to prevent scale formation

    DOEpatents

    Brunson, Roy J.

    1982-01-01

    Scale formation during the liquefaction of lower ranking coals and similar carbonaceous materials is significantly reduced and/or prevented by pretreatment with a pretreating agent selected from the group consisting of phthalic acid, phthalic anhydride, pyromellitic acid and pyromellitic anhydride. The pretreatment is believed to convert the scale-forming components to the corresponding phthalate and/or pyromellitate prior to liquefaction. The pretreatment is accomplished at a total pressure within the range from about 1 to about 2 atmospheres. Temperature during pretreatment will generally be within the range from about 5.degree. to about 80.degree. C.

  8. Impact of Corn Stover Composition on Hemicellulose Conversion during Dilute Acid Pretreatment and Enzymatic Cellulose Digestibility of the Pretreated Solids

    SciTech Connect

    Weiss, N. D.; Farmer, J. D.; Schell, D. J.

    2010-01-01

    This study assessed the impact of corn stover compositional variability on xylose conversion yields during dilute acid pretreatment and on enzymatic cellulose digestibility of the resulting pretreated solids. Seven compositionally-different stovers obtained from various locations throughout the United States were pretreated at three different conditions in triplicate in a pilot-scale continuous reactor. At the same pretreatment severity, a 2-fold increase in monomeric xylose yield and a 1.5-fold increase in enzymatic cellulose digestibility from their lowest values were found. Similar results were observed at the other pretreatment conditions. It was found that xylose conversion yields decreased with increasing acid neutralization capacity or soil content of the corn stover. Xylose yields also increased with increasing xylan content. No other significant correlations between corn stover's component concentrations and conversion yields were found.

  9. Dilute acid pretreatment of lignocellulose for whole slurry ethanol fermentation.

    PubMed

    Jung, Young Hoon; Kim, In Jung; Kim, Hyun Kyung; Kim, Kyoung Heon

    2013-03-01

    Dilute sulfuric acid pretreatment of oil palm empty fruit bunches (EFB) followed by the whole slurry fermentation of the pretreated EFB slurry was investigated. The optimized pretreatment conditions were at 1% (w/v) sulfuric acid with 3 min ramping to 190 °C in a microwave digester. Pretreated and washed EFB exhibited enzymatic digestibility of 88.5% of theoretical glucose yield after 48 h of hydrolysis. When the whole slurry of pretreated and neutralized EFB was used in simultaneous saccharification and fermentation (SSF) using cellulase and Saccharomyces cerevisiae, sulfuric acid-pretreated EFB resulted in 52.5% of theoretical ethanol yield based on total glucan in the untreated initial EFB after 72 h of SSF. When pretreated EFB slurry was treated with activated carbon before subjecting to SSF, the SSF furnished 87.5% ethanol yield based on the initial glucan content in untreated EFB (after 48 h of SSF). PMID:23395763

  10. Helically agitated mixing in dry dilute acid pretreatment enhances the bioconversion of corn stover into ethanol

    PubMed Central

    2014-01-01

    Background Dry dilute acid pretreatment at extremely high solids loading of lignocellulose materials demonstrated promising advantages of no waste water generation, less sugar loss, and low steam consumption while maintaining high hydrolysis yield. However, the routine pretreatment reactor without mixing apparatus was found not suitable for dry pretreatment operation because of poor mixing and mass transfer. In this study, helically agitated mixing was introduced into the dry dilute acid pretreatment of corn stover and its effect on pretreatment efficiency, inhibitor generation, sugar production, and bioconversion efficiency through simultaneous saccharification and ethanol fermentation (SSF) were evaluated. Results The overall cellulose conversion taking account of cellulose loss in pretreatment was used to evaluate the efficiency of pretreatment. The two-phase computational fluid dynamics (CFD) model on dry pretreatment was established and applied to analyze the mixing mechanism. The results showed that the pretreatment efficiency was significantly improved and the inhibitor generation was reduced by the helically agitated mixing, compared to the dry pretreatment without mixing: the ethanol titer and yield from cellulose in the SSF reached 56.20 g/L and 69.43% at the 30% solids loading and 15 FPU/DM cellulase dosage, respectively, corresponding to a 26.5% increase in ethanol titer and 17.2% increase in ethanol yield at the same fermentation conditions. Conclusions The advantage of helically agitated mixing may provide a prototype of dry dilute acid pretreatment processing for future commercial-scale production of cellulosic ethanol. PMID:24387051

  11. Characterization of oxalic acid pretreatment on lignocellulosic biomass using oxalic acid recovered by electrodialysis.

    PubMed

    Lee, Hong-Joo; Seo, Young-Jun; Lee, Jae-Won

    2013-04-01

    The properties of pretreated biomass and hydrolysate obtained by oxalic acid pretreatment using oxalic acid recovered through electrodialysis (ED) were investigated. Most of the oxalic acid was recovered and some of the fermentation inhibitors were removed by ED. For the original hydrolysate, the ethanol production was very low and fermentable sugars were not completely consumed by Pichia stipitis during fermentation. Ethanol yield was less than 0.12 g/g in all stage. For the ED-treated hydrolysate, ethanol production was increased by up to two times in all stages compared to the original hydrolysate. The highest ethanol production was 19.38 g/l after 72 h which correspond to the ethanol yield of 0.33 g/g. Enzymatic conversion of the cellulose to glucose for all the pretreated biomass was in the range of 76.03 and 77.63%. The hydrolysis rate on each pretreated biomass was not significantly changed when oxalic acid recovered by ED was used for pretreatment. PMID:23422303

  12. Dilute oxalic acid pretreatment for high total sugar recovery in pretreatment and subsequent enzymatic hydrolysis.

    PubMed

    Qing, Qing; Huang, Meizi; He, Yucai; Wang, Liqun; Zhang, Yue

    2015-12-01

    Oxalic acid was evaluated as an alternative reagent to mineral inorganic acid in pretreatment of corncob to achieve high xylose yield in addition to highly digestible solid residue. A quadratic polynomial model of xylose formation was developed for optimization of pretreatment process by the response surface methodology based on the impact factors of pretreatment temperature, reaction time, acid concentration, and solid-to-liquid ratio. The highest xylose yield was 94.3 % that was obtained under the pretreatment condition of 140 °C for 40 min with 0.5 wt% oxalic acid at a solid loading of 7.5 %. Under these conditions, the xylose yield results of verification experiments were very close to the model prediction, which indicated that the model was applicable. The solid residue generated under this condition also demonstrated a satisfactory enzymatic digestibility and fermentability. PMID:26494137

  13. Fuel ethanol production from corn stover under optimized dilute phosphoric acid pretreatment and enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ethanol is a renewable oxygenated fuel. Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Generation of fermentable sugars from corn stover involves pretreatment and enzymatic saccharification. Pretreatment is crucial as nat...

  14. Cellulose degradation in alkaline media upon acidic pretreatment and stabilisation.

    PubMed

    Testova, Lidia; Nieminen, Kaarlo; Penttilä, Paavo A; Serimaa, Ritva; Potthast, Antje; Sixta, Herbert

    2014-01-16

    The present study reports on a revised kinetic model for alkaline degradation of cellulose accounting for primary peeling/stopping reactions as well as for alkaline hydrolysis followed by secondary peeling. Oxalic acid pretreated cotton linters was utilised as the model substrate for the prehydrolysis-soda anthraquinone process. The main emphasis was investigating the effect of end-group stabilising additives such as sodium borohydride (BH), anthraquinone (AQ), and anthraquinone-2-sulphonic acid sodium salt (AQS) on the rates of the yield loss reactions. BH and AQS ensured a cellulose yield gain of 13% and 11%, respectively, compared to the reference. Both stabilisation agents decreased the content of the reducing end groups in the samples, while in the case of AQS stabilisation a 25% increase in carboxyl group content compared to the reference was also observed. As expected, the addition of end group stabilisers resulted in a significant decrease in the peeling-to-stopping rate constants ratio. PMID:24188853

  15. Ethanol production from industrial hemp: effect of combined dilute acid/steam pretreatment and economic aspects.

    PubMed

    Kuglarz, Mariusz; Gunnarsson, Ingólfur B; Svensson, Sven-Erik; Prade, Thomas; Johansson, Eva; Angelidaki, Irini

    2014-07-01

    In the present study, combined steam (140-180°C) and dilute-acid pre-hydrolysis (0.0-2.0%) were applied to industrial hemp (Cannabis sativa L.), as pretreatment for lignocellulosic bioethanol production. The influence of the pretreatment conditions and cultivation type on the hydrolysis and ethanol yields was also evaluated. Pretreatment with 1% sulfuric acid at 180°C resulted in the highest glucose yield (73-74%) and ethanol yield of 75-79% (0.38-0.40 g-ethanol/g-glucose). Taking into account the costs of biomass processing, from field to ethanol facility storage, the field-dried hemp pretreated at the optimal conditions showed positive economic results. The type of hemp cultivation (organic or conventional) did not influence significantly the effectiveness of the pretreatment as well as subsequent enzymatic hydrolysis and ethanol fermentation. PMID:24821202

  16. Redistribution of Lignin Caused by Dilute Acid Pretreatment of Biomass

    SciTech Connect

    Johnson, D. K.; Donohoe, B. S.; Katahira, R.; Tucker, M. P.; Vinzant, T. B.; Himmel, M. E.

    2012-01-01

    Research conducted at NREL has shown that lignin undergoes a phase transition during thermochemical pretreatments conducted above its glass transition temperature. The lignin coalesces within the plant cell wall and appears as microscopic droplets on cell surfaces. It is clear that pretreatment causes significant changes in lignin distribution in pretreatments at all scales from small laboratory reactors to pilot scale reactors. A method for selectively extracting lignin droplets from the surfaces of pretreated cell walls has allowed us to characterize the chemical nature and molecular weight distribution of this fraction. The effect of lignin redistribution on the digestibility of pretreated solids has also been tested. It is clear that removal of the droplets increases the digestibility of pretreated corn stover. The improved digestibility could be due to decreased non-specific binding of enzymes to lignin in the droplets, or because the droplets no longer block access to cellulose.

  17. Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass

    PubMed Central

    2011-01-01

    Background Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. Results During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe2+ ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe2+ ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe2+ ion pretreatment, in which delamination and fibrillation of the cell wall were observed. Conclusions By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose. PMID:22074910

  18. Elucidating the Role of Ferrous Ion Cocatalyst in Enhancing Dilute Acid Pretreatment of Lignocellulosic Biomass

    SciTech Connect

    Wei, H.; Donohoe, B. S.; Vinzant, T. B.; Ciesielski, P. N.; Wang, W.; Gedvilas, L. M.; Zeng, Y.; Johnson, D. K.; Ding, S. Y.; Himmel, M. E.; Tucker, M. P.

    2011-01-01

    Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe{sup 2+} ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe{sup 2+} ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe{sup 2+} ion pretreatment, in which delamination and fibrillation of the cell wall were observed. By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.

  19. Characterization of lignin derived from water-only and dilute acid flowthrough pretreatment of poplar wood at elevated temperatures

    SciTech Connect

    Zhang, Libing; Yan, Lishi; Wang, Zheming; Laskar, Dhrubojyoti D.; Swita, Marie S.; Cort, John R.; Yang, Bin

    2015-12-01

    In this study, flowthrough pretreatment of biomass has high potential to valorize lignin derivatives to high-value products, which is vital to enhance the economy of biorefinery plants. Comprehensive understanding of lignin behaviors and solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of providing flexible platform for lignin utilization. In this study, the effects of flowthrough pretreatment conditions on lignin separation from poplar wood were reported as well as the characteristics of three sub-sets of lignin produced from the pretreatment, including residual lignin in pretreated solid residues (ReL), recovered insoluble lignin in pretreated liquid (RISL), and recovered soluble lignin in pretreatment liquid (RSL). Both the water-only and 0.05% (w/w) sulfuric acid pretreatments were performed at temperatures from 160 to 270°C on poplar wood in a flowthrough reactor system for 2-10 min. Results showed that water-only flowthrough pretreatment primarily removed syringyl (S units). Increased temperature and/or the addition of sulfuric acid enhanced the removal of guaiacyl (G units) compared to water-only pretreatments at lower temperatures, resulting in nearly complete removal of lignin from the biomass. Results also suggested that more RISL was recovered than ReL and RSL in both dilute acid and water-only flowthrough pretreatment at elevated temperatures. NMR spectra of the RISL revealed significant β-O-4 cleavage, α-β deoxygenation to form cinnamyl-like end groups, and slight β-5 repolymerization in both water-only and dilute acid flowthrough pretreatments. In conclusion, elevated temperature and/or dilute acid greatly enhanced lignin removal to almost 100% by improving G unit removal besides S unit removal in flowthrough system. A new lignin chemistry transformation pathway was proposed and revealed the complexity of lignin structural change during

  20. Can Delignification Decrease Cellulose Digestibility in Acid Pretreated Corn Stover?

    SciTech Connect

    Ishizawa, C. I.; Jeoh, T.; Adney, W. S.; Himmel, M. E.; Johnson, D. K.; Davis, M. F.

    2009-01-01

    It has previously been shown that the improved digestibility of dilute acid pretreated corn stover is at least partially due to the removal of xylan and the consequent increase in accessibility of the cellulose to cellobiohydrolase enzymes. We now report on the impact that lignin removal has on the accessibility and digestibility of dilute acid pretreated corn stover. Samples of corn stover were subjected to dilute sulfuric acid pretreatment with and without simultaneous (partial) lignin removal. In addition, some samples were completely delignified after the pretreatment step using acidified sodium chlorite. The accessibility and digestibility of the samples were tested using a fluorescence-labeled cellobiohydrolase (Trichoderma reesei Cel7A) purified from a commercial cellulase preparation. Partial delignification of corn stover during dilute acid pretreatment was shown to improve cellulose digestibility by T. reesei Cel7A; however, decreasing the lignin content below 5% (g g{sup -1}) by treatment with acidified sodium chlorite resulted in a dramatic reduction in cellulose digestibility. Importantly, this effect was found to be enhanced in samples with lower xylan contents suggesting that the near complete removal of xylan and lignin may cause aggregation of the cellulose microfibrils resulting in decreased cellulase accessibility.

  1. Whole slurry saccharification and fermentation of maleic acid-pretreated rice straw for ethanol production.

    PubMed

    Jung, Young Hoon; Park, Hyun Min; Kim, Kyoung Heon

    2015-09-01

    We evaluated the feasibility of whole slurry (pretreated lignocellulose) saccharification and fermentation for producing ethanol from maleic acid-pretreated rice straw. The optimized conditions for pretreatment were to treat rice straw at a high temperature (190 °C) with 1 % (w/v) maleic acid for a short duration (3 min ramping to 190 °C and 3 min holding at 190 °C). Enzymatic digestibility (based on theoretical glucose yield) of cellulose in the pretreated rice straw was 91.5 %. Whole slurry saccharification and fermentation of pretreated rice straw resulted in 83.2 % final yield of ethanol based on the initial quantity of glucan in untreated rice straw. These findings indicate that maleic acid pretreatment results in a high yield of ethanol from fermentation of whole slurry even without conditioning or detoxification of the slurry. Additionally, the separation of solids and liquid is not required; therefore, the economics of cellulosic ethanol fuel production are significantly improved. We also demonstrated whole slurry saccharification and fermentation of pretreated lignocellulose, which has rarely been reported. PMID:25930209

  2. Optimization of the dilute maleic acid pretreatment of wheat straw

    PubMed Central

    2009-01-01

    Background In this study, the dilute maleic acid pretreatment of wheat straw is optimized, using pretreatment time, temperature and maleic acid concentration as design variables. A central composite design was applied to the experimental set up. The response factors used in this study are: (1) glucose benefits from improved enzymatic digestibility of wheat straw solids; (2) xylose benefits from the solubilization of xylan to the liquid phase during the pretreatment; (3) maleic acid replenishment costs; (4) neutralization costs of pretreated material; (5) costs due to furfural production; and (6) heating costs of the input materials. For each response factor, experimental data were fitted mathematically. After data translation to €/Mg dry straw, determining the relative contribution of each response factor, an economic optimization was calculated within the limits of the design variables. Results When costs are disregarded, an almost complete glucan conversion to glucose can be reached (90% from solids, 7%-10% in liquid), after enzymatic hydrolysis. During the pretreatment, up to 90% of all xylan is converted to monomeric xylose. Taking cost factors into account, the optimal process conditions are: 50 min at 170°C, with 46 mM maleic acid, resulting in a yield of 65 €/Mg (megagram = metric ton) dry straw, consisting of 68 €/Mg glucose benefits (from solids: 85% of all glucan), 17 €/Mg xylose benefits (from liquid: 80% of all xylan), 17 €/Mg maleic acid costs, 2.0 €/Mg heating costs and 0.68 €/Mg NaOH costs. In all but the most severe of the studied conditions, furfural formation was so limited that associated costs are considered negligible. Conclusions After the dilute maleic acid pretreatment and subsequent enzymatic hydrolysis, almost complete conversion of wheat straw glucan and xylan is possible. Taking maleic acid replenishment, heating, neutralization and furfural formation into account, the optimum in the dilute maleic acid pretreatment of

  3. Breakdown of Cell Wall Nanostructure in Dilute Acid Pretreated Biomass

    SciTech Connect

    Pingali, Sai Venkatesh; Urban, Volker S; Heller, William T; McGaughey, Joseph; O'Neill, Hugh Michael; Foston, Marcus B; Myles, Dean A A; Ragauskas, Arthur J; Evans, Barbara R

    2010-01-01

    The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient way. Here, we use small-angle neutron scattering (SANS) to characterize morphological changes in switchgrass lignocellulose across molecular to sub-micron length scales resulting from the industrially-relevant dilute acid pretreatment method. Our results demonstrate that dilute acid pretreatment increases the cross-sectional radius of the crystalline cellulose fibril. This change is accompanied by removal of hemicellulose and the formation of Rg ~ 135 lignin aggregates. The structural signature of smooth cell wall surfaces is observed at length scales larger than 1000 , and it remains remarkably invariable during pretreatment. This study elucidates the interplay of the different biomolecular components in the break down process of switchgrass by dilute acid pretreatment. The results are important for the development of efficient strategies of biomass to biofuel conversion.

  4. Characterization of pilot-scale dilute acid pretreatment performance using deacetylated corn stover

    PubMed Central

    2014-01-01

    Background Dilute acid pretreatment is a promising process technology for the deconstruction of low-lignin lignocellulosic biomass, capable of producing high yields of hemicellulosic sugars and enhancing enzymatic yields of glucose as part of a biomass-to-biofuels process. However, while it has been extensively studied, most work has historically been conducted at relatively high acid concentrations of 1 - 4% (weight/weight). Reducing the effective acid loading in pretreatment has the potential to reduce chemical costs both for pretreatment and subsequent neutralization. Additionally, if acid loadings are sufficiently low, capital requirements associated with reactor construction may be significantly reduced due to the relaxation of requirements for exotic alloys. Despite these benefits, past efforts have had difficulty obtaining high process yields at low acid loadings without supplementation of additional unit operations, such as mechanical refining. Results Recently, we optimized the dilute acid pretreatment of deacetylated corn stover at low acid loadings in a 1-ton per day horizontal pretreatment reactor. This effort included more than 25 pilot-scale pretreatment experiments executed at reactor temperatures ranging from 150 – 170°C, residence times of 10 – 20 minutes and hydrolyzer sulfuric acid concentrations between 0.15 – 0.30% (weight/weight). In addition to characterizing the process yields achieved across the reaction space, the optimization identified a pretreatment reaction condition that achieved total xylose yields from pretreatment of 73.5% ± 1.5% with greater than 97% xylan component balance closure across a series of five runs at the same condition. Feedstock reactivity at this reaction condition after bench-scale high solids enzymatic hydrolysis was 77%, prior to the inclusion of any additional conversion that may occur during subsequent fermentation. Conclusions This study effectively characterized a range of pretreatment reaction

  5. Impacts of Deacetylation Prior to Dilute Acid Pretreatment on the Bioethanol Process

    SciTech Connect

    Chen, X.; Shekiro, J.; Franden, M. A.; Wang, W.; Johnson, D. K.; Zhang, M.; Kuhn, E.; Tucker, M. P.

    2011-12-01

    Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from lignocellulosic biomass. During dilute acid pretreatment, xylan depolymerizes to form soluble xylose monomers and oligomers. Because the xylan found in nature is highly acetylated, the formation of xylose monomers requires two steps: (1) cleavage of the xylosidic bonds, and (2) cleavage of covalently bonded acetyl ester groups. Results: In this study, we show that the latter may be the rate limiting step for xylose monomer formation. Furthermore, acetyl groups are also found to be a cause of biomass recalcitrance and hydrolyzate toxicity. While the removal of acetyl groups from native corn stover by alkaline de-esterification prior to pretreatment improves overall process yields, the exact impact is highly dependent on the corn stover variety in use. Xylose monomer yields in pretreatment generally increases by greater than 10%. Compared to pretreated corn stover controls, the deacetylated corn stover feedstock is approximately 20% more digestible after pretreatment. Finally, by lowering hydrolyzate toxicity, xylose utilization and ethanol yields are further improved during fermentation by roughly 10% and 7%, respectively. In this study, several varieties of corn stover lots were investigated to test the robustness of the deacetylation-pretreatment-saccharification-fermentation process. Conclusions: Deacetylation shows significant improvement on glucose and xylose yields during pretreatment and enzymatic hydrolysis, but it also reduces hydrolyzate toxicity during fermentation, thereby improving ethanol yields and titer. The magnitude of effect is dependent on the selected corn stover variety, with several varieties achieving improvements of greater than 10% xylose yield in pretreatment, 20% glucose yield in low solids enzymatic hydrolysis and 7% overall ethanol yield.

  6. The effect of dilute acid pre-treatment process in bioethanol production from durian (Durio zibethinus) seeds waste

    NASA Astrophysics Data System (ADS)

    Ghazali, K. A.; Salleh, S. F.; Riayatsyah, T. M. I.; Aditiya, H. B.; Mahlia, T. M. I.

    2016-03-01

    Lignocellulosic biomass is one of the promising feedstocks for bioethanol production. The process starts from pre-treatment, hydrolysis, fermentation, distillation and finally obtaining the final product, ethanol. The efficiency of enzymatic hydrolysis of cellulosic biomass depends heavily on the effectiveness of the pre-treatment step which main function is to break the lignin structure of the biomass. This work aims to investigate the effects of dilute acid pre-treatment on the enzymatic hydrolysis of durian seeds waste to glucose and the subsequent bioethanol fermentation process. The yield of glucose from dilute acid pre-treated sample using 0.6% H2SO4 and 5% substrate concentration shows significant value of 23.4951 g/L. Combination of dilute acid pre-treatment and enzymatic hydrolysis using 150U of enzyme able to yield 50.0944 g/L of glucose content higher compared to normal pre-treated sample of 8.1093 g/L. Dilute acid pre-treatment sample also shows stable and efficient yeast activity during fermentation process with lowest glucose content at 2.9636 g/L compared to 14.7583g/L for normal pre-treated sample. Based on the result, it can be concluded that dilute acid pre-treatment increase the yield of ethanol from bioethanol production process.

  7. Enhancement of volatile fatty acids production from rice straw via anaerobic digestion with chemical pretreatment.

    PubMed

    Park, Gwon Woo; Kim, Ilgook; Jung, Kwonsu; Seo, Charles; Han, Jong-In; Chang, Ho Nam; Kim, Yeu-Chun

    2015-08-01

    Rice straw is one of the most abundant renewable biomass sources and was selected as the feedstock for the production of volatile fatty acids (VFAs) from which microbial biodiesel can be produced. Two kinds of chemical pretreatments involving nitric acid and sodium hydroxide were investigated at 150 °C with 20 min of reaction time. The nitric acid pretreatment generated the most hemicellulose hydrolyzate, while significant reduction of the lignin occurred with sodium hydroxide pretreatment. Anaerobic digestion of 20 g/L rice straw yielded 6.00 and 7.09 g VFAs/L with 0.5% HNO3 and 2% NaOH, respectively. The VFAs yield with 2% NaOH was 0.35 g/g. PMID:25764527

  8. A comparative study of ethanol production using dilute acid, ionic liquid and AFEX™ pretreated corn stover

    PubMed Central

    2014-01-01

    Background In a biorefinery producing cellulosic biofuels, biomass pretreatment will significantly influence the efficacy of enzymatic hydrolysis and microbial fermentation. Comparison of different biomass pretreatment techniques by studying the impact of pretreatment on downstream operations at industrially relevant conditions and performing comprehensive mass balances will help focus attention on necessary process improvements, and thereby help reduce the cost of biofuel production. Results An on-going collaboration between the three US Department of Energy (DOE) funded bioenergy research centers (Great Lakes Bioenergy Research Center (GLBRC), Joint BioEnergy Institute (JBEI) and BioEnergy Science Center (BESC)) has given us a unique opportunity to compare the performance of three pretreatment processes, notably dilute acid (DA), ionic liquid (IL) and ammonia fiber expansion (AFEXTM), using the same source of corn stover. Separate hydrolysis and fermentation (SHF) was carried out using various combinations of commercially available enzymes and engineered yeast (Saccharomyces cerevisiae 424A) strain. The optimal commercial enzyme combination (Ctec2: Htec2: Multifect Pectinase, percentage total protein loading basis) was evaluated for each pretreatment with a microplate-based assay using milled pretreated solids at 0.2% glucan loading and 15 mg total protein loading/g of glucan. The best enzyme combinations were 67:33:0 for DA, 39:33:28 for IL and 67:17:17 for AFEX. The amounts of sugar (kg) (glucose: xylose: total gluco- and xylo-oligomers) per 100 kg of untreated corn stover produced after 72 hours of 6% glucan loading enzymatic hydrolysis were: DA (25:2:2), IL (31:15:2) and AFEX (26:13:7). Additionally, the amounts of ethanol (kg) produced per 100 kg of untreated corn stover and the respective ethanol metabolic yield (%) achieved with exogenous nutrient supplemented fermentations were: DA (14.0, 92.0%), IL (21.2, 93.0%) and AFEX (20.5, 95.0%), respectively

  9. Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

    PubMed

    Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

    2016-03-01

    Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility. PMID:26744804

  10. Treatment of olive mill wastewater by chemical processes: effect of acid cracking pretreatment.

    PubMed

    Hande Gursoy-Haksevenler, B; Arslan-Alaton, Idil

    2014-01-01

    The effect of acid cracking (pH 2.0; T 70 °C) and filtration as a pretreatment step on the chemical treatability of olive mill wastewater (chemical oxygen demand (COD) 150,000 m/L; total organic carbon (TOC) 36,000 mg/L; oil-grease 8,200 mg/L; total phenols 3,800 mg/L) was investigated. FeCl3 coagulation, Ca(OH)2 precipitation, electrocoagulation using stainless steel electrodes and the Fenton's reagent were applied as chemical treatment methods. Removal performances were examined in terms of COD, TOC, oil-grease, total phenols, colour, suspended solids and acute toxicity with the photobacterium Vibrio fischeri. Significant oil-grease (95%) and suspended solids (96%) accompanied with 58% COD, 43% TOC, 39% total phenols and 80% colour removals were obtained by acid cracking-filtration pretreatment. Among the investigated chemical treatment processes, electrocoagulation and the Fenton's reagent were found more effective after pretreatment, especially in terms of total phenols removal. Total phenols removal increased from 39 to 72% when pretreatment was applied, while no significant additional (≈10-15%) COD and TOC removals were obtained when acid cracking was coupled with chemical treatment. The acute toxicity of the original olive mill wastewater sample increased considerably after pretreatment from 75 to 89% (measured for the 10-fold diluted wastewater sample). An operating cost analysis was also performed for the selected chemical treatment processes. PMID:24718336

  11. Bioethanol production from deacetylated yellow poplar pretreated with oxalic acid recovered through electrodialysis.

    PubMed

    Kundu, Chandan; Jeong, So-Yeon; Lee, Jae-Won

    2016-05-01

    Electrodialysis (ED) was used to develop a multistage oxalic acid recovery and pretreatment system to produce ethanol from deacetylated yellow poplar. Pretreatment of the biomass was performed at 150°C for 42 min using 0.16 M oxalic acid. The efficiency of oxalic acid recovery from the hydrolysate reached up to 92.32% in all the stages. Ethanol production and ethanol yield of ED-treated hydrolysate in each stage showed a uniform pattern ranging from 6.81 g/L to 7.21 g/L and 0.40 g/g to 0.43 g/g, respectively. The results showed that efficiency of ethanol production increased when deacetylated biomass and ED process was used. Ethanol yield from the pretreated biomass using simultaneous saccharification and fermentation (SSF) was in the range of 80.59-83.36% in all the stages. The structural characterization of the pretreated biomass at each stage was investigated and structural changes were not significantly different among the various pretreated biomass. PMID:26943934

  12. Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

    PubMed

    Qin, Lei; Liu, Li; Li, Wen-Chao; Zhu, Jia-Qing; Li, Bing-Zhi; Yuan, Ying-Jin

    2016-06-01

    This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis. PMID:26970919

  13. Comparative Study of SPORL and Dilute Acid Pretreatments of Spruce for Cellulosic Ethanol Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The performance of two pretreatment methods, Sulfite Pretreatment to Overcome Recalcitrance of Lignocellulose (SPORL) and Dilute Acid (DA), was compared in pretreating softwood (spruce) for fuel ethanol production under the same conditions of temperature (180°C), time (30 min), sulfuric acid loading...

  14. Modeling Sucrose Hydrolysis in Dilute Sulfuric Acid Solutions at Pretreatment Conditions for Lignocellulosic Biomass

    SciTech Connect

    Bower, S.; Wickramasinghe, R.; Nagle, N. J.; Schell, D. J.

    2008-01-01

    Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25 g/l sucrose with 0.1-2.0% (w/w) sulfuric acid concentrations were treated at temperatures of 160-200 C for 3-12 min. Sucrose was observed to completely hydrolyze at all treatment conditions. However, appreciable concentrations of fructose and glucose were detected and glucose was found to be significantly more stable than fructose. Different mathematical approaches were used to fit the kinetic parameters for acid-catalyzed thermal degradation of these sugars. Since both sugars may survive dilute acid pretreatment, they could provide an additional carbon source for production of ethanol and other bio-based products.

  15. Optimization of dilute acid pretreatment of water hyacinth biomass for enzymatic hydrolysis and ethanol production

    PubMed Central

    Idrees, Muhammad; Adnan, Ahmad; Sheikh, Shahzad; Qureshic, Fahim Ashraf

    2013-01-01

    The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature (oC), time (hr) and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables with P < 0.05. High F and R2 values and low P-value for hydrolysis yield indicated the model predictability. The pretreated biomass producing 39.96 g/l, 39.86 g/l and 37.9 g/l of reducing sugars during enzymatic hydrolysis with yield 79.93, 78.71 and 75.9 % from PA, MA and SA treated respectively. The order of catalytic effectiveness for hydrolysis yield was found to be phosphoric acid > maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker's yeast (Sacchromyces cerveasiae). PMID:26417215

  16. Characterization of lignin derived from water-only and dilute acid flowthrough pretreatment of poplar wood at elevated temperatures

    DOE PAGESBeta

    Zhang, Libing; Yan, Lishi; Wang, Zheming; Laskar, Dhrubojyoti D.; Swita, Marie S.; Cort, John R.; Yang, Bin

    2015-12-01

    In this study, flowthrough pretreatment of biomass has high potential to valorize lignin derivatives to high-value products, which is vital to enhance the economy of biorefinery plants. Comprehensive understanding of lignin behaviors and solubilization chemistry in aqueous pretreatment such as water-only and dilute acid flowthrough pretreatment is of fundamental importance to achieve the goal of providing flexible platform for lignin utilization. In this study, the effects of flowthrough pretreatment conditions on lignin separation from poplar wood were reported as well as the characteristics of three sub-sets of lignin produced from the pretreatment, including residual lignin in pretreated solid residues (ReL),more » recovered insoluble lignin in pretreated liquid (RISL), and recovered soluble lignin in pretreatment liquid (RSL). Both the water-only and 0.05% (w/w) sulfuric acid pretreatments were performed at temperatures from 160 to 270°C on poplar wood in a flowthrough reactor system for 2-10 min. Results showed that water-only flowthrough pretreatment primarily removed syringyl (S units). Increased temperature and/or the addition of sulfuric acid enhanced the removal of guaiacyl (G units) compared to water-only pretreatments at lower temperatures, resulting in nearly complete removal of lignin from the biomass. Results also suggested that more RISL was recovered than ReL and RSL in both dilute acid and water-only flowthrough pretreatment at elevated temperatures. NMR spectra of the RISL revealed significant β-O-4 cleavage, α-β deoxygenation to form cinnamyl-like end groups, and slight β-5 repolymerization in both water-only and dilute acid flowthrough pretreatments. In conclusion, elevated temperature and/or dilute acid greatly enhanced lignin removal to almost 100% by improving G unit removal besides S unit removal in flowthrough system. A new lignin chemistry transformation pathway was proposed and revealed the complexity of lignin structural change

  17. Facile, room-temperature pre-treatment of rice husks with tetrabutylphosphonium hydroxide: Enhanced enzymatic and acid hydrolysis yields.

    PubMed

    Lau, B B Y; Luis, E T; Hossain, M M; Hart, W E S; Cencia-Lay, B; Black, J J; To, T Q; Aldous, L

    2015-12-01

    Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10-40wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes. PMID:26342336

  18. Docosahexaenoic acid pretreatment confers protection and functional improvements after acute spinal cord injury in adult rats.

    PubMed

    Figueroa, Johnny D; Cordero, Kathia; Baldeosingh, Keisha; Torrado, Aranza I; Walker, Robert L; Miranda, Jorge D; Leon, Marino De

    2012-02-10

    Currently, few interventions have been shown to successfully limit the progression of secondary damage events associated with the acute phase of spinal cord injury (SCI). Docosahexaenoic acid (DHA, C22:6 n-3) is neuroprotective when administered following SCI, but its potential as a pretreatment modality has not been addressed. This study used a novel DHA pretreatment experimental paradigm that targets acute cellular and molecular events during the first week after SCI in rats. We found that DHA pretreatment reduced functional deficits during the acute phase of injury, as shown by significant improvements in Basso-Beattie-Bresnahan (BBB) locomotor scores, and the detection of transcranial magnetic motor evoked potentials (tcMMEPs) compared to vehicle-pretreated animals. We demonstrated that, at 7 days post-injury, DHA pretreatment significantly increased the percentage of white matter sparing, and resulted in axonal preservation, compared to the vehicle injections. We found a significant increase in the survival of NG2+, APC+, and NeuN+ cells in the ventrolateral funiculus (VLF), dorsal corticospinal tract (dCST), and ventral horns, respectively. Interestingly, these DHA protective effects were observed despite the lack of inhibition of inflammatory markers for monocytes/macrophages and astrocytes, ED1/OX42 and GFAP, respectively. DHA pretreatment induced levels of Akt and cyclic AMP responsive element binding protein (CREB) mRNA and protein. This study shows for the first time that DHA pretreatment ameliorates functional deficits, and increases tissue sparing and precursor cell survival. Further, our data suggest that DHA-mediated activation of pro-survival/anti-apoptotic pathways may be independent of its anti-inflammatory effects. PMID:21970623

  19. Docosahexaenoic Acid Pretreatment Confers Protection and Functional Improvements after Acute Spinal Cord Injury in Adult Rats

    PubMed Central

    Figueroa, Johnny D.; Cordero, Kathia; Baldeosingh, Keisha; Torrado, Aranza I.; Walker, Robert L.; Miranda, Jorge D.

    2012-01-01

    Abstract Currently, few interventions have been shown to successfully limit the progression of secondary damage events associated with the acute phase of spinal cord injury (SCI). Docosahexaenoic acid (DHA, C22:6 n-3) is neuroprotective when administered following SCI, but its potential as a pretreatment modality has not been addressed. This study used a novel DHA pretreatment experimental paradigm that targets acute cellular and molecular events during the first week after SCI in rats. We found that DHA pretreatment reduced functional deficits during the acute phase of injury, as shown by significant improvements in Basso-Beattie-Bresnahan (BBB) locomotor scores, and the detection of transcranial magnetic motor evoked potentials (tcMMEPs) compared to vehicle-pretreated animals. We demonstrated that, at 7 days post-injury, DHA pretreatment significantly increased the percentage of white matter sparing, and resulted in axonal preservation, compared to the vehicle injections. We found a significant increase in the survival of NG2+, APC+, and NeuN+ cells in the ventrolateral funiculus (VLF), dorsal corticospinal tract (dCST), and ventral horns, respectively. Interestingly, these DHA protective effects were observed despite the lack of inhibition of inflammatory markers for monocytes/macrophages and astrocytes, ED1/OX42 and GFAP, respectively. DHA pretreatment induced levels of Akt and cyclic AMP responsive element binding protein (CREB) mRNA and protein. This study shows for the first time that DHA pretreatment ameliorates functional deficits, and increases tissue sparing and precursor cell survival. Further, our data suggest that DHA-mediated activation of pro-survival/anti-apoptotic pathways may be independent of its anti-inflammatory effects. PMID:21970623

  20. Effect of sulfuric and phosphoric acid pretreatments on enzymatic hydrolysis of corn stover.

    PubMed

    Um, Byung-Hwan; Karim, M; Henk, Linda

    2003-01-01

    The pretreatment of corn stover with H2SO4 and H3PO4 was investigated. Pretreatments were carried out from 30 to 120 min in a batch reactor at 121 degrees C, with acid concentrations ranging from 0 to 2% (w/v) at a solid concentration of 5% (w/v). Pretreated corn stover was washed with distilled water until the filtrate was adjusted to pH 7.0, followed by surfactant swelling of the cellulosic fraction in a 0-10% (w/v) solution of Tween-80 at room temperature for 12 h. The dilute acid treatment proved to be a very effective method in terms of hemicellulose recovery and cellulose digestibility. Hemicellulose recovery was 62-90%, and enzymatic digestibility of the cellulose that remained in the solid was >80% with 2% (w/v) acid. In all cases studied, the performance of H2SO4 pretreatment (hemicellulose recovery and cellulose digestibility) was significantly better than obtained with H3PO4. Enzymatic hydrolysis was more effective using surfactant than without it, producing 10-20% more sugar. Furthermore, digestibility was investigated as a function of hemicellulose removal. It was found that digestibility was more directly related to hemicellulose removal than to delignification. PMID:12721479

  1. Salicylic acid and heat acclimation pretreatment protects Laminaria japonica sporophyte (Phaeophyceae) from heat stress

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Tang, Xuexi; Wang, You

    2010-07-01

    Possible mediatory roles of heat acclimation and salicylic acid in protecting the sporophyte of marine macroalga Laminaria japonica (Phaeophyceae) from heat stress were studied. Heat stress resulted in oxidative injury in the kelp blades. Under heat stress significant accumulation of hydrogen peroxide (H2O2) and malonaldehyde (MDA), a membrane lipid peroxidation product, and a drastic decrease in chlorophyll a content were recorded. Activity of the enzymatic antioxidant system was drastically affected by heat stress. The activity of superoxide dismutase (SOD) was significantly increased while peroxidase (POD), catalase (CAT) and glutathione peroxidase (GPX) were greatly inhibited and, simultaneously, phenylalanine ammonia-lyase was activated while polyphenol oxidase (PPO) was inhibited. Both heat acclimation pretreatment and exogenous application of salicylic acid alleviated oxidative damage in kelp blades. Blades receiving heat acclimation pretreatment and exogenous salicylic acid prior to heat stress exhibited a reduced increase in H2O2 and MDA content, and a lower reduction in chlorophyll a content. Pretreatment with heat acclimation and salicylic acid elevated activities of SOD, POD, CAT, GPX and PPO. Considering these results collectively, we speculate that the inhibition of antioxidant enzymes is a possible cause of the heat-stress-induced oxidative stress in L. japonica, and enhanced thermotolerance may be associated, at least in part, with the elevated activity of the enzymatic antioxidant system.

  2. Thermo-chemical pretreatment of rice straw for further processing for levulinic acid production.

    PubMed

    Elumalai, Sasikumar; Agarwal, Bhumica; Sangwan, Rajender S

    2016-10-01

    A variety of pretreatment protocols for rice straw fiber reconstruction were evaluated under mild conditions (upto 0.2%wt. and 121°C) with the object of improving polymer susceptibility to chemical attack while preserving carbohydrate sugars for levulinic acid (LA) production. Each of the protocols tested significantly enhanced pretreatment recoveries of carbohydrate sugars and lignin, and a NaOH protocol showed the most promise, with enhanced carbohydrate preservation (upto 20% relative to the other protocols) and more effective lignin dissolution (upto 60%). Consequently, post-pretreatment fibers were evaluated for LA preparation using an existing co-solvent system consisting of HCl and THF, in addition supplementation of DMSO was attempted, in order to improve final product recovery. In contrast to pretreatment response, H2SO4 protocol fibers yielded highest LA conc. (21%wt. with 36% carbohydrate conversion efficiency) under the modest reaction conditions. Apparent spectroscopic analysis witnessed for fiber destruction and delocalization of inherent constituents during pretreatment protocols. PMID:27371796

  3. Improving production of volatile fatty acids from food waste fermentation by hydrothermal pretreatment.

    PubMed

    Yin, Jun; Wang, Kun; Yang, Yuqiang; Shen, Dongsheng; Wang, Meizhen; Mo, Han

    2014-11-01

    Food waste (FW) was pretreated by a hydrothermal method and then fermented for volatile fatty acid (VFAs) production. The soluble substance in FW increased after hydrothermal pretreatment (⩽200 °C). Higher hydrothermal temperature would lead to mineralization of the organic compounds. The optimal temperature for organic dissolution was 180 °C, at which FW dissolved 42.5% more soluble chemical oxygen demand than the control. VFA production from pretreated FW fermentation was significantly enhanced compared with the control. The optimal hydrothermal temperature was 160 °C with a VFA yield of 0.908 g/g VSremoval. Butyrate and acetate were the prevalent VFAs followed by propionate and valerate. FW fermentation was inhibited after 200 °C pretreatment. The VFAs were extracted from the fermentation broth by liquid-liquid extraction. The VFA recovery was 50-70%. Thus, 0.294-0.411 g VFAs could be obtained per gram of hydrothermally pretreated FW (in dry weight) by this method. PMID:25218204

  4. Effect of pelleting on the recalcitrance and bioconversion of dilute-acid pretreated corn stover

    SciTech Connect

    Allison E Ray; Amber Hoover; Gary Gresham

    2012-07-01

    Background: Knowledge regarding the performance of densified biomass in biochemical processes is limited. The effects of densification on biochemical conversion are explored here. Methods: Pelleted corn stover samples were generated from bales that were milled to 6.35 mm. Low-solids acid pretreatment and simultaneous saccharification and fermentation were performed to evaluate pretreatment efficacy and ethanol yields achieved for pelleted and ground stover (6.35 mm and 2 mm) samples. Both pelleted and 6.35-mm ground stover were evaluated using a ZipperClave® reactor under high-solids, process-relevant conditions for multiple pretreatment severities (Ro), followed by enzymatic hydrolysis of the washed, pretreated solids. Results: Monomeric xylose yields were significantly higher for pellets (approximately 60%) than for ground formats (approximately 38%). Pellets achieved approximately 84% of theoretical ethanol yield (TEY); ground stover formats had similar profiles, reaching approximately 68% TEY. Pelleting corn stover was not detrimental to pretreatment efficacy for both low- and high-solids conditions, and even enhanced ethanol yields.

  5. Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

    PubMed

    Mohagheghi, Ali; Schell, Daniel J

    2010-04-01

    Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently. PMID:19998277

  6. Long term storage of dilute acid pretreated corn stover feedstock and ethanol fermentability evaluation.

    PubMed

    Zhang, Jian; Shao, Shuai; Bao, Jie

    2016-02-01

    This study reported a new solution of lignocellulose feedstock storage based on the distributed pretreatment concept. The dry dilute sulfuric acid pretreatment (DDAP) was conducted on corn stover feedstock, instead of ammonia fiber explosion pretreatment. Then the dry dilute acid pretreated corn stover was stored for three months during summer season with high temperature and humidity. No negative aspects were found on the physical property, composition, hydrolysis yield and ethanol fermentability of the long term stored pretreated corn stover, plus the additional merits including no chemicals recovery operation, anti-microbial contaminant environment from stronger acid and inhibitor contents, as well as the mild and slow hydrolysis in the storage. The new pretreatment method expanded the distributed pretreatment concept of feedstock storage with potential for practical application. PMID:26639616

  7. A novel diffusion-biphasic hydrolysis coupled kinetic model for dilute sulfuric acid pretreatment of corn stover.

    PubMed

    Chen, Longjian; Zhang, Haiyan; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Han, Lujia

    2015-02-01

    Kinetic experiments on the dilute sulfuric acid pretreatment of corn stover were performed. A high xylan removal and a low inhibitor concentration were achieved by acid pretreatment. A novel diffusion-hydrolysis coupled kinetic model was proposed. The contribution to the xylose yield was analyzed by the kinetic model. Compared with the inhibitor furfural negatively affecting xylose yield, the fast and slow-hydrolyzing xylan significantly contributed to the xylose yield, however, their dominant roles were dependent on reaction temperature and time. The impact of particle size and acid concentration on the xylose yield were also investigated. The diffusion process may significantly influence the hydrolysis of large particles. Increasing the acid concentration from 0.15 M to 0.30 M significantly improved the xylose yield, whereas the extent of improvement decreased to near-quantitative when further increasing acid loading. These findings shed some light on the mechanism for dilute sulfuric acid hydrolysis of corn stover. PMID:25479388

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

    PubMed

    van der Pol, Edwin; Bakker, Rob; van Zeeland, Alniek; Sanchez Garcia, David; Punt, Arjen; Eggink, Gerrit

    2015-04-01

    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 pretreatment included acetic, glycolic and coumaric acid in concentrations up to 40, 21 and 2.5 g/kg dry weight bagasse respectively. Alkaline pretreated material contained up to 45 g/kg bagasse DW of sodium. Acid and autohydrolysis pretreatment results in a furan formation of 14 g/kg and 25 g/kg DW bagasse respectively. Enzyme monomerization efficiencies of pretreated solid material after 72 h were 81% for acid pretreatment, 77% for autohydrolysis and 57% for alkaline pretreatment. Solid material was washed with superheated water to decrease the amount of by-products. Washing decreased organic acid, phenol and furan concentrations in solid material by at least 60%, without a major sugar loss. PMID:25643957

  9. High Xylose Yields from Dilute Acid Pretreatment of Corn Stover Under Process-Relevant Conditions

    SciTech Connect

    Weiss, N. D.; Nagle, N. J.; Tucker, M. P.; Elander, R. T.

    2009-01-01

    Pretreatment experiments were carried out to demonstrate high xylose yields at high solids loadings in two different batch pretreatment reactors under process-relevant conditions. Corn stover was pretreated with dilute sulfuric acid using a 4-l Steam Digester and a 4-l stirred ZipperClave{reg_sign} reactor. Solids were loaded at 45% dry matter (wt/wt) after sulfuric acid catalyst impregnation using nominal particle sizes of either 6 or 18 mm. Pretreatment was carried out at temperatures between 180 and 200 C at residence times of either 90 or 105 s. Results demonstrate an ability to achieve high xylose yields (>80%) over a range of pretreatment conditions, with performance showing little dependence on particle size or pretreatment reactor type. The high xylose yields are attributed to effective catalyst impregnation and rapid rates of heat transfer during pretreatment.

  10. Sulfuric Acid Pretreatment and Enzymatic Hydrolysis of Photoperiod Sensitvie Sorghum for Ethanol Production

    SciTech Connect

    F Xu; Y Shi; X Wu

    2011-12-31

    Photoperiod sensitive (PS) sorghum, with high soluble sugar content, high mass yield and high drought tolerance in dryland environments, has great potential for bioethanol production. The effect of diluted sulfuric acid pretreatment on enzymatic hydrolysis was investigated. Hydrolysis efficiency increased from 78.9 to 94.4% as the acid concentration increased from 0.5 to 1.5%. However, the highest total glucose yield (80.3%) occurred at the 1.0% acid condition because of the significant cellulose degradation at the 1.5% concentration. Synchrotron wide-angle X-ray diffraction was used to study changes of the degree of crystallinity. With comparison of cellulosic crystallinity and adjusted cellulosic crystallinity, the crystalline cellulose decreased after low acidic concentration (0.5%) applied, but did not change significantly, as the acid concentration increased. Scanning electron microscopy was also employed to understand how the morphological structure of PS sorghum changed after pretreatment. Under current processing conditions, the total ethanol yield is 74.5% (about 0.2 g ethanol from 1 g PS sorghum). A detail mass balance was also provided.

  11. Sequential acid-/alkali-pretreatment of empty palm fruit bunch fiber.

    PubMed

    Kim, Seonghun; Park, Jang Min; Seo, Jeong-Woo; Kim, Chul Ho

    2012-04-01

    Pretreatment processes are key technologies for generating fermentable sugars based on lignocellulosic biomass. In this study, we developed a novel method for empty palm fruit bunch fiber (EPFBF) using sequential pretreatment with dilute acid and then alkali. Dilute sulfuric acid was used in the first step, which removed 90% of the hemicellulose and 32% of the lignin, but left most of the cellulose under the optimum pretreatment condition. Sodium hydroxide was then applied in the second step, which extracted lignin effectively with a 70% delignification yield, partially disrupting the ordered fibrils of the EPFBF and thus enhancing the enzyme digestibility of the cellulose. The sequentially pretreated biomass consisted of 82% cellulose, less than 1% hemicellulose, and 30% lignin content afterward. The pretreated biomasses morphologically revealed rough, porous, and irregularly ordered surfaces for enhancing enzyme digestibility. These results indicate that the sequentially acid/alkali-pretreated EPFBF could be broadly useful as a novel biomass. PMID:22306078

  12. Improved Multivariate Calibration Models for Corn Stover Feedstock and Dilute-Acid Pretreated Corn Stover

    SciTech Connect

    Wolfrum, E. J.; Sluiter, A. D.

    2009-01-01

    We have studied rapid calibration models to predict the composition of a variety of biomass feedstocks by correlating near-infrared (NIR) spectroscopic data to compositional data produced using traditional wet chemical analysis techniques. The rapid calibration models are developed using multivariate statistical analysis of the spectroscopic and wet chemical data. This work discusses the latest versions of the NIR calibration models for corn stover feedstock and dilute-acid pretreated corn stover. Measures of the calibration precision and uncertainty are presented. No statistically significant differences (p = 0.05) are seen between NIR calibration models built using different mathematical pretreatments. Finally, two common algorithms for building NIR calibration models are compared; no statistically significant differences (p = 0.05) are seen for the major constituents glucan, xylan, and lignin, but the algorithms did produce different predictions for total extractives. A single calibration model combining the corn stover feedstock and dilute-acid pretreated corn stover samples gave less satisfactory predictions than the separate models.

  13. Powerful peracetic acid-ionic liquid pretreatment process for the efficient chemical hydrolysis of lignocellulosic biomass.

    PubMed

    Uju; Goto, Masahiro; Kamiya, Noriho

    2016-08-01

    The aim of this work was to design a new method for the efficient saccharification of lignocellulosic biomass (LB) using a combination of peracetic acid (PAA) pretreatment with ionic liquid (IL)-HCl hydrolysis. The pretreatment of LBs with PAA disrupted the lignin fractions, enhanced the dissolution of LB and led to a significant increase in the initial rate of the IL-HCl hydrolysis. The pretreatment of Bagasse with PAA prior to its 1-buthyl-3-methylimidazolium chloride ([Bmim][Cl])-HCl hydrolysis, led to an improvement in the cellulose conversion from 20% to 70% in 1.5h. Interestingly, the 1-buthyl-3-methylpyridium chloride ([Bmpy][Cl])-HCl hydrolysis of Bagasse gave a cellulose conversion greater than 80%, with or without the PAA pretreatment. For LB derived from seaweed waste, the cellulose conversion reached 98% in 1h. The strong hydrolysis power of [Bmpy][Cl] was attributed to its ability to transform cellulose I to II, and lowering the degree of polymerization of cellulose. PMID:27174616

  14. Utilizing acid pretreatment and electrospinning to improve biocompatibility of poly(glycolic acid) for tissue engineering.

    PubMed

    Boland, Eugene D; Telemeco, Todd A; Simpson, David G; Wnek, Gary E; Bowlin, Gary L

    2004-10-15

    Poly(glycolic acid) (PGA) has a long history as a bioresorbable polymer. Its biocompatibility is widely accepted, yet PGA is often rejected as a soft-tissue scaffold because of fibrous encapsulation. The goal of this study was to improve the soft-tissue biocompatibility of PGA by producing scaffolds composed of small-diameter fibers through electrospinning and subjecting these scaffolds to a concentrated hydrochloric acid (HCL) pretreatment. The theory is that small-diameter fibers will elicit a reduced immune response and HCl treatment will improve cellular interactions. Scaffolds were characterized in terms of fiber diameter and pore area via image-analysis software. Biocompatibility was assessed through a WST-1 cell-proliferation assay (in vitro) with the use of rat cardiac fibroblasts and rat intramuscular implantations (in vivo). Fibers produced ranged in diameter from 0.22 to 0.88 microm with pore areas from 1.84 to 13.22 microm(2). The untreated scaffold composed of 0.88-microm fibers was encapsulated in vivo and supported the lowest rates of cell proliferation. On the contrary, the acid pretreated scaffold with 0.22-microm fibers was incorporated into the surrounding tissue and exhibited proliferation rates that exceeded the control populations on tissue-culture plastic. In conclusion, this study has shown the ability to improve the biocompatibility of PGA through acid pretreatment of scaffolds comprised of submicron fiber diameters. PMID:15368238

  15. Structural changes of oil palm empty fruit bunch (OPEFB) after fungal and phosphoric acid pretreatment.

    PubMed

    Isroi; Ishola, Mofoluwake M; Millati, Ria; Syamsiah, Siti; Cahyanto, Muhammad N; Niklasson, Claes; Taherzadeh, Mohammad J

    2012-01-01

    Oil palm empty fruit bunch (OPEFB) was pretreated using white-rot fungus Pleurotus floridanus, phosphoric acid or their combination, and the results were evaluated based on the biomass components, and its structural and morphological changes. The carbohydrate losses after fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 7.89%, 35.65%, and 33.77%, respectively. The pretreatments changed the hydrogen bonds of cellulose and linkages between lignin and carbohydrate, which is associated with crystallinity of cellulose of OPEFB. Lateral Order Index (LOI) of OPEFB with no pretreatment, with fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 2.77, 1.42, 0.67, and 0.60, respectively. Phosphoric acid pretreatment showed morphological changes of OPEFB, indicated by the damage of fibre structure into smaller particle size. The fungal-, phosphoric acid-, and fungal followed by phosphoric acid pretreatments have improved the digestibility of OPEFB's cellulose by 4, 6.3, and 7.4 folds, respectively. PMID:23247371

  16. Antioxidative Peptides Derived from Enzyme Hydrolysis of Bone Collagen after Microwave Assisted Acid Pre-Treatment and Nitrogen Protection

    PubMed Central

    Lin, Yun-Jian; Le, Guo-Wei; Wang, Jie-Yun; Li, Ya-Xin; Shi, Yong-Hui; Sun, Jin

    2010-01-01

    This study focused on the preparation method of antioxidant peptides by enzymatic hydrolysis of bone collagen after microwave assisted acid pre-treatment and nitrogen protection. Phosphoric acid showed the highest ability of hydrolysis among the four other acids tested (hydrochloric acid, sulfuric acid and/or citric acid). The highest degree of hydrolysis (DH) was 9.5% using 4 mol/L phosphoric acid with a ratio of 1:6 under a microwave intensity of 510 W for 240 s. Neutral proteinase gave higher DH among the four protease tested (Acid protease, neutral protease, Alcalase and papain), with an optimum condition of: (1) ratio of enzyme and substrate, 4760 U/g; (2) concentration of substrate, 4%; (3) reaction temperature, 55 °C and (4) pH 7.0. At 4 h, DH increased significantly (P < 0.01) under nitrogen protection compared with normal microwave assisted acid pre-treatment hydrolysis conditions. The antioxidant ability of the hydrolysate increased and reached its maximum value at 3 h; however DH decreased dramatically after 3 h. Microwave assisted acid pre-treatment and nitrogen protection could be a quick preparatory method for hydrolyzing bone collagen. PMID:21151439

  17. Prognostic significance of pretreated serum lactate dehydrogenase level in nasopharyngeal carcinoma among Chinese population

    PubMed Central

    Zhang, Mingwei; Wei, Shushan; Su, Li; Lv, Wenlong; Hong, Jinsheng

    2016-01-01

    Abstract Background: A large number of studies have investigated the prognostic value of pretreated lactate dehydrogenase (LDH) level in nasopharyngeal carcinoma (NPC) patients while the role of it was inconsistent and inconclusive. Hence, the aim of the current study was to conduct a meta-analysis of all published studies to quantify the prognostic impact of pretreated serum LDH in NPC for Chinese population. Objectives: The aim of the current study was to conduct a meta-analysis of all published studies to quantify the prognostic impact of pretreated serum lactate dehydrogenase (LDH) in nasopharyngeal carcinoma (NPC) for Chinese population. Methods: The PubMed, Medline, Embase, and Web of Science databases were searched for studies that assessed survival outcome and LDH in NPC. Overall survival (OS) was the primary survival outcome. Distant metastasis-free survival (DMFS) and disease-free survival (DFS) were secondary outcomes. The pooled hazard ratios (HRs), associated with 95% confidence intervals (95% CIs), were combined to calculate overall effects. The Cochran Q and I2 statistics were used to assess heterogeneity. When apparent heterogeneity was observed, sensitivity and meta-regression analyses were performed to explore its origin. Results: Sixteen studies, which included 14,803 patients, were enrolled in the current meta-analysis to yield statistics. Overall, the pooled HR for OS in 11 eligible studies with high LDH level was 1.79 (95% CI = 1.47–2.12), and the pooled HR for DMFS in 9 eligible studies with high LDH level was 1.85 (95% CI = 1.48–2.22). Meanwhile, the pooled HR for DFS in 5 eligible studies with high LDH level was 1.63 (95% CI = 1.34–1.91). Egger test and funnel plots revealed that the publication bias in the current meta-analysis was insignificant. Conclusions: The present meta-analysis demonstrated that high pretreated LDH level is significantly associated with poorer OS, DMFS, and DFS, suggesting that pretreated LDH could

  18. Development of an estimation model for the evaluation of the energy requirement of dilute acid pretreatments of biomass☆

    PubMed Central

    Mafe, Oluwakemi A.T.; Davies, Scott M.; Hancock, John; Du, Chenyu

    2015-01-01

    This study aims to develop a mathematical model to evaluate the energy required by pretreatment processes used in the production of second generation ethanol. A dilute acid pretreatment process reported by National Renewable Energy Laboratory (NREL) was selected as an example for the model's development. The energy demand of the pretreatment process was evaluated by considering the change of internal energy of the substances, the reaction energy, the heat lost and the work done to/by the system based on a number of simplifying assumptions. Sensitivity analyses were performed on the solid loading rate, temperature, acid concentration and water evaporation rate. The results from the sensitivity analyses established that the solids loading rate had the most significant impact on the energy demand. The model was then verified with data from the NREL benchmark process. Application of this model on other dilute acid pretreatment processes reported in the literature illustrated that although similar sugar yields were reported by several studies, the energy required by the different pretreatments varied significantly. PMID:26109752

  19. Recovery of calcium carbonate from steelmaking slag and utilization for acid mine drainage pre-treatment.

    PubMed

    Mulopo, J; Mashego, M; Zvimba, J N

    2012-01-01

    The conversion of steelmaking slag (a waste product of the steelmaking process) to calcium carbonate (CaCO(3)) was tested using hydrochloric acid, ammonium hydroxide and carbon dioxide via a pH-swing process. Batch reactors were used to assess the technical feasibility of calcium carbonate recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effects of key process parameters, such as the amount of acid (HCl/calcium molar ratio), the pH and the CO(2) flow rate were considered. It was observed that calcium extraction from steelmaking slag significantly increased with an increase in the amount of hydrochloric acid. The CO(2) flow rate also had a positive effect on the carbonation reaction rate but did not affect the morphology of the calcium carbonate produced for values less than 2 L/min. The CaCO(3) recovered from the bench scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with the commercial laboratory grade CaCO(3). PMID:22643421

  20. Enzymatic hydrolysis and fermentation of dilute acid pretreated cornstalk to biohydrogen

    NASA Astrophysics Data System (ADS)

    Pan, C. M.; Fan, Y. T.; Hou, H. W.

    2010-03-01

    The coupling method of acid pretreatment and enzymatic hydrolysis of cornstalk for hydrogen production was investigated in this study. Experimental results showed that temperature, pH and enzyme loading all had an individual significant influence on soluble sugar yield and Ps. The optimum condition for soluble sugar was close to that for Ps. The maximum hydrogen yield from cornstalk by anaerobic mixed microflora was 209.8 ml/g-TVS on the optimum enzymatic hydrolysis condition which was 52 °C of temperature, pH4.8 and 9.4 IU/g of enzyme loading.

  1. Investigating Mass Transport Limitations on Xylan Hydrolysis During Dilute Acid Pretreatment of Poplar

    SciTech Connect

    Mittal, Ashutosh; Pilath, Heid M.; Parent, Yves; Chatterjee, Siddharth G.; Donohoe, Bryon S.; Yarbrough, John M.; Himmel, Michael E.; Nimlos, Mark R.; Johnson, David K.

    2014-04-28

    Mass transport limitations could be an impediment to achieving high sugar yields during biomass pretreatment and thus be a critical factor in the economics of biofuels production. The objective of this work was to study the mass transfer restrictions imposed by the structure of biomass on the hydrolysis of xylan during dilute acid pretreatment of biomass. Mass transfer effects were studied by pretreating poplar wood at particle sizes ranging from 10 micrometers to 10 mm. This work showed a significant reduction in the rate of xylan hydrolysis in poplar when compared to the intrinsic rate of hydrolysis for isolated xylan that is possible in the absence of mass transfer. In poplar samples we observed no significant difference in the rates of xylan hydrolysis over more than two orders of magnitude in particle size. It appears that no additional mass transport restrictions are introduced by increasing particle size from 10 micrometers to 10 mm. This work suggests that the rates of xylan hydrolysis in biomass particles are limited primarily by the diffusion of hydrolysis products out of plant cell walls. A mathematical description is presented to describe the kinetics of xylan hydrolysis that includes transport of the hydrolysis products through biomass into the bulk solution. The modeling results show that the effective diffusion coefficient of the hydrolysis products in the cell wall is several orders of magnitude smaller than typical values in other applications signifying the role of plant cell walls in offering resistance to diffusion of the hydrolysis products.

  2. A novel sono-assisted acid pretreatment of chili post harvest residue for bioethanol production.

    PubMed

    Sindhu, Raveendran; Binod, Parameswaran; Pandey, Ashok

    2016-08-01

    The objective of the present study was to develop a sono-assisted acid pretreatment strategy for the effective removal of lignin and hemicelluloses and to improve the sugar yield from chili post harvest residue. Operational parameters that affect the pretreatment efficiency were studied and optimized. Inhibitor analysis of the hydrolyzate revealed that major fermentation inhibitors like furfural, hydroxymethyl furfural and organic acids like citric acid, succinic acid and propionic acid were absent. Changes in structural properties of the biomass were studied in relation to the pretreatment process using scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) analysis, and the changes in chemical composition was also monitored. The biomass pretreated with the optimized novel method yielded 0.465g/g of reducing sugars on enzymatic hydrolysis. Fermentation of the non-detoxified hydrolysate yielded 2.14% of bioethanol with a fermentation efficiency of 71.03%. PMID:26949055

  3. Thermochemical pretreatments for enhancing succinic acid production from industrial hemp (Cannabis sativa L.).

    PubMed

    Gunnarsson, Ingólfur B; Kuglarz, Mariusz; Karakashev, Dimitar; Angelidaki, Irini

    2015-04-01

    The aim of this study was to develop an efficient thermochemical method for treatment of industrial hemp biomass, in order to increase its bioconversion to succinic acid. Industrial hemp was subjected to various thermochemical pretreatments using 0-3% H2SO4, NaOH or H2O2 at 121-180°C prior to enzymatic hydrolysis. The influence of the different pretreatments on hydrolysis and succinic acid production by Actinobacillus succinogenes 130Z was investigated in batch mode, using anaerobic bottles and bioreactors. Enzymatic hydrolysis and fermentation of hemp material pretreated with 3% H2O2 resulted in the highest overall sugar yield (73.5%), maximum succinic acid titer (21.9 g L(-1)), as well as the highest succinic acid yield (83%). Results obtained clearly demonstrated the impact of different pretreatments on the bioconversion efficiency of industrial hemp into succinic acid. PMID:25682224

  4. Optimization of dilute sulfuric acid pretreatment and enzymatic saccharification of corn stover for efficient ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute acid pretreatment is a promising pretreatment technology for conversion of lignocellulosic biomass to fuel ethanol. Corn stover (supplied by a local farmer) used in this study contained 37.0±0.4% cellulose, 31.3±0.6% hemicelluloses, and 17.8±0.2% lignin. Generation of fermentable sugars from ...

  5. Insights into the effect of dilute acid, hot water and alkaline pretreatment on cellulose accessible surface area and overall porosity of Populus

    SciTech Connect

    Meng, Xianzhi; Wells, Tyrone; Sun, Qining; Huang, Fang; Ragauskas, Arthur J.

    2015-06-19

    Pretreatment is known to render biomass more reactive to cellulase by altering the chemical compositions as well as physical structures of biomass. Simons stain technique along with mercury porosimetry were applied on the acid, neutral, and alkaline pretreated materials to measure the accessible surface area of cellulose and pore size distribution of Populus. Results indicated that acid pretreatment is much more effective than water and alkaline pretreatment in terms of cellulose accessibility increase. Further investigation suggests that lignin does not dictate cellulose accessibility to the extent that hemicellulose does, but it does restrict xylan accessibility which in turn controls the access of cellulase to cellulose. The most interesting finding is that severe acid pretreatment significantly decreases the average pore size, i.e., 90% average size decrease could be observed after 60 min dilute acid pretreatment at 160 °C; moreover, the nano-pore space formed between coated microfibrils is increased after pretreatment, especially for the acid pretreatment, suggesting this particular type of biomass porosity is probably the most fundamental barrier to effective enzymatic hydrolysis.

  6. Insights into the effect of dilute acid, hot water and alkaline pretreatment on cellulose accessible surface area and overall porosity of Populus

    DOE PAGESBeta

    Meng, Xianzhi; Wells, Tyrone; Sun, Qining; Huang, Fang; Ragauskas, Arthur J.

    2015-06-19

    Pretreatment is known to render biomass more reactive to cellulase by altering the chemical compositions as well as physical structures of biomass. Simons stain technique along with mercury porosimetry were applied on the acid, neutral, and alkaline pretreated materials to measure the accessible surface area of cellulose and pore size distribution of Populus. Results indicated that acid pretreatment is much more effective than water and alkaline pretreatment in terms of cellulose accessibility increase. Further investigation suggests that lignin does not dictate cellulose accessibility to the extent that hemicellulose does, but it does restrict xylan accessibility which in turn controls themore » access of cellulase to cellulose. The most interesting finding is that severe acid pretreatment significantly decreases the average pore size, i.e., 90% average size decrease could be observed after 60 min dilute acid pretreatment at 160 °C; moreover, the nano-pore space formed between coated microfibrils is increased after pretreatment, especially for the acid pretreatment, suggesting this particular type of biomass porosity is probably the most fundamental barrier to effective enzymatic hydrolysis.« less

  7. Effects of pretreatment on the microbial community and l-lactic acid production in vinasse fermentation.

    PubMed

    Liu, Jianguo; Wang, Qunhui; Wang, Shuang; Sun, Xiaohong; Ma, Hongzhi; Tushiro, Yukihiro

    2012-12-15

    Microwave-alkali and steam-alkali coupled pretreatments were carried out to improve the yield and optical purity of l-lactic acid produced using vinasse fermentation. Lactobacillus casei was inoculated into the system to initiate fermentation. Polymerase chain reaction denaturing gradient gel electrophoresis was used to analyze the microbial community during fermentation with and without the pretreatments. The original bacterial genus in vinasse was essentially inactivated, whereas L. casei became the dominant genus after 24h of fermentation. The system subjected to microwave-alkali coupled pretreatment released more reducing sugars and produced more lactic acid (up to 30.32g/L), which is twice that without pretreatment. In addition, the proportion of lactic acid in the organic acids also increased. The optical purity of the l-lactic acid produced under the microwave-alkali coupled pretreatment reached 91%, which is 2% higher than that under the steam-alkali coupled pretreatment and 7% higher than that under the control conditions. Therefore, the microwave-alkali coupled pretreatment is an effective method for the highly efficient bioconversion of vinasse into bioenergy. PMID:22959862

  8. Efficacy of acidic pretreatment for the saccharification and fermentation of alginate from brown macroalgae.

    PubMed

    Wang, Damao; Yun, Eun Ju; Kim, Sooah; Kim, Do Hyoung; Seo, Nari; An, Hyun Joo; Kim, Jae-Han; Cheong, Nam Yong; Kim, Kyoung Heon

    2016-06-01

    This study was performed to evaluate the effectiveness of acidic pretreatment in increasing the enzymatic digestibility of alginate from brown macroalgae. Pretreatment with 1 % (w/v) sulfuric acid at 120 °C for 30 min produced oligosaccharides, mannuronic acid, and guluronic acid. Enzymatic saccharification of pretreated alginate by alginate lyases produced 52.2 % of the theoretical maximal sugar yield, which was only 7.5 % higher than the sugar yield obtained with unpretreated alginate. Mass spectrometric analyses of products of the two reactions revealed that acidic pretreatment and enzymatic saccharification produced saturated monomers (i.e., mannuronic and guluronic acid) with saturated oligosaccharides and unsaturated monomers (i.e., 4-deoxy-L-erythro-5-hexoseulose uronic acid; DEH), respectively. While DEH is further metabolized by microorganisms, mannuronic acid and guluronic acid are not metabolizable. Because of the poor efficacy in increasing enzymatic digestibility and owing to the formation of non-fermentable saturated monomers, acidic pretreatment cannot be recommended for enzymatic saccharification and fermentation of alginate. PMID:26923145

  9. Improving ethanol production from alfalfa stems via ambient-temperature acid pretreatment and washing.

    PubMed

    Zhou, Shengfei; Weimer, Paul J; Hatfield, Ronald D; Runge, Troy M; Digman, Matthew

    2014-10-01

    The concept of co-production of liquid fuel (ethanol) along with animal feed on farm was proposed, and the strategy of using ambient-temperature acid pretreatment, ensiling and washing to improve ethanol production from alfalfa stems was investigated. Alfalfa stems were separated and pretreated with sulfuric acid at ambient-temperature after harvest, and following ensiling, after which the ensiled stems were subjected to simultaneous saccharification and fermentation (SSF) for ethanol production. Ethanol yield was improved by ambient-temperature sulfuric acid pretreatment before ensiling, and by washing before SSF. It was theorized that the acid pretreatment at ambient temperature partially degraded hemicellulose, and altered cell wall structure, resulted in improved cellulose accessibility, whereas washing removed soluble ash in substrates which could inhibit the SSF. The pH of stored alfalfa stems can be used to predict the ethanol yield, with a correlation coefficient of +0.83 for washed alfalfa stems. PMID:25151072

  10. Fractionation of Cynara cardunculus (Cardoon) Biomass by Dilute-Acid Pretreatment

    NASA Astrophysics Data System (ADS)

    Ballesteros, Mercedes; Negro, M. José; Manzanares, Paloma; Ballesteros, Ignacio; Sáez, Felicia; Oliva, J. Miguel

    Cynara cardunculus L. (cardoon) is a Mediterranean perennial herb offering good potential as substrate for sustainable production of bioethanol. In this work the first approach to the study of dilute-acid pretreatment of cardoon biomass for biological conversion was made. The influence of temperature (160-200°C), acid concentration (0-0.2% [w/w]), and solid concentration (5-10% [w/v]) in the formation of free sugars and sugar decomposition products in the prehydrolyzate was studied using a response surface methodology. Results show a negative interaction effect between acid concentration and temperature in xylose recovery yield in prehydrolyzate, whereas dry matter concentration does not exert a significant effect. Xylose recovery yield reaches a maximum of about 80% of the content in dry untreated raw material at 180°C and 0.1 or 0.2% acid addition. At these conditions the ratio of monomers found in prehydrolyzate in relation to total sugar yield for xylose is close to 100%. Furfural concentration, the major furan determined in the prehydrolyzate, increases as pretreatment severity rises. Maximum furfural yield of 4.2 g/100 g dry untreated raw material was found at 200°C and 0.2% acid concentration. The yield of furfural at the conditions in which maximum xylose recovery is attained is substantially lower, less than 2 g/100 g dry untreated raw material. This fact supports the idea of using moderate temperatures in dilute-acid processes, which at the same time provides reasonably high sugar recovery yield and avoids high inhibitory products formation.

  11. Pretreatment of Gymnema sylvestre revealed the protection against acetic acid-induced ulcerative colitis in rats

    PubMed Central

    2014-01-01

    Background Overproduction of free radicals and decreased antioxidant capacity are well-known risk factors for inflammatory bowel diseases. Gymnema sylvestre (GS) leaves extract is distinguished for its anti-diabetic, antioxidant and anti-inflammatory properties. Present study is designed to evaluate the preventative activities of GS against acetic acid (AA)-induced ulcerative colitis in Wistar rats. Methods Experimentally ulcerative colitis (UC) was induced by AA in animals pretreated with three different doses of GS leaves extract (50, 100, 200 mg/kg/day) and a single dose of mesalazine (MES, 300 mg/kg/day) for seven days. Twenty four hours later, animals were sacrificed and the colonic tissues were collected. Colonic mucus content was determined using Alcian blue dye binding technique. Levels of thiobarbituric acid reactive substances (TBARS), total glutathione sulfhydryl group (T-GSH) and non-protein sulfhydryl group (NPSH) as well as the activity of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were estimated in colon tissues. Colonic nucleic acids (DNA and RNA) and total protein (TP) concentrations were also determined. Levels of pro-inflammatory cytokines including interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) as well as prostaglandin E2 (PGE2) and nitric oxide (NO) were estimated in colonic tissues. The histopathological changes of the colonic tissues were also observed. Results In AA administered group TBARS levels were increased, while colonic mucus content, T-GSH and NP-SH, SOD and CAT were reduced in colon. Pretreatment with GS inhibited TBARS elevation as well as mucus content, T-GSH and NP-SH reduction. Enzymatic activities of SOD and CAT were brought back to their normal levels in GS pretreated group. A significant reduction in DNA, RNA and TP levels was seen following AA administration and this inhibition was significantly eliminated by GS treatment. GS pretreatment also inhibited

  12. EFFECT OF ANATOMICAL FRACTIONATION ON THE ENZYMATIC HYDROLYSIS OF ACID AND ALKALINE PRETREATED CORN STOVER

    SciTech Connect

    K. B. Duguid; M. D. Montross; C. W. Radtke; C. L. Crofcheck; L. M. Wendt; S. A. Shearer

    2009-11-01

    Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect for conversion. An ideal feedstock would require low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis. Corn stover fractions were separated by hand and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The stover fractions were also pretreated with either 0, 0.4, or 0.8% NaOH for 2 hours at room temperature, washed, autoclaved and saccharified. In addition, acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF were 65% (standard error of 15.9%) for husks and 29% (standard error of 1.8%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.

  13. Optimizing ethanol and methane production from steam-pretreated, phosphoric acid-impregnated corn stover.

    PubMed

    Bondesson, Pia-Maria; Dupuy, Aurélie; Galbe, Mats; Zacchi, Guido

    2015-02-01

    Pretreatment is of vital importance in the production of ethanol and methane from agricultural residues. In this study, the effects of steam pretreatment with phosphoric acid on enzymatic hydrolysis (EH), simultaneous saccharification and fermentation (SSF), anaerobic digestion (AD) and the total energy output at three different temperatures were investigated. The effect of separating the solids for SSF and the liquid for AD was also studied and compared with using the whole slurry first in SSF and then in AD. Furthermore, the phosphoric acid was compared to previous studies using sulphuric acid or no catalyst. Using phosphoric acid resulted in higher yields than when no catalyst was used. However, compared with sulphuric acid, an improved yield was only seen with phosphoric acid in the case of EH. The higher pretreatment temperatures (200 and 210 °C) resulted in the highest yields after EH and SSF, while the highest methane yield was obtained with the lower pretreatment temperature (190 °C). The highest yield in terms of total energy recovery (78 %) was obtained after pretreatment at 190 °C, but a pretreatment temperature of 200 °C is, however, the best alternative since fewer steps are required (whole slurry in SSF and then in AD) and high product yields were obtained (76 %). PMID:25399069

  14. Lipid production by Cryptococcus curvatus on hydrolysates derived from corn fiber and sweet sorghum bagasse following dilute acid pretreatment.

    PubMed

    Liang, Yanna; Jarosz, Kimberly; Wardlow, Ashley T; Zhang, Ji; Cui, Yi

    2014-08-01

    Corn fiber and sweet sorghum bagasse (SSB) are both pre-processed lignocellulosic materials that can be used to produce liquid biofuels. Pretreatment using dilute sulfuric acid at a severity factor of 1.06 and 1.02 released 83.2 and 86.5 % of theoretically available sugars out of corn fiber and SSB, respectively. The resulting hydrolysates derived from pretreatment of SSB at SF of 1.02 supported growth of Cryptococcus curvatus well. In 6 days, the dry cell density reached 10.8 g/l with a lipid content of 40 % (w/w). Hydrolysates from corn fiber, however, did not lead to any significant cell growth even with addition of nutrients. In addition to consuming glucose, xylose, and arabinose, C. curvatus also utilized formic acid, acetic acid, 4-hydroxymethylfurfural, and levulinic acid for growth. Thus, C. curvatus appeared to be an excellent yeast strain for producing lipids from hydrolysates developed from lignocellulosic feedstocks. PMID:24928546

  15. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    DOE PAGESBeta

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M.; Li, Hongjia; Wyman, Charles E.; Langan, Paul; Ragauskas, Art J.; et al

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have largemore » implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  16. Effect of lignin content on changes occurring in poplar cellulose ultrastructure during dilute acid pretreatment

    SciTech Connect

    Sun, Qining; Foston, Marcus; Meng, Xianzhi; Sawada, Daisuke; Pingali, Sai Venkatesh; O’Neill, Hugh M.; Li, Hongjia; Wyman, Charles E.; Langan, Paul; Ragauskas, Art J.; Kumar, Rajeev

    2014-10-14

    Obtaining a better understanding of the complex mechanisms occurring during lignocellulosic deconstruction is critical to the continued growth of renewable biofuel production. A key step in bioethanol production is thermochemical pretreatment to reduce plant cell wall recalcitrance for downstream processes. Previous studies of dilute acid pretreatment (DAP) have shown significant changes in cellulose ultrastructure that occur during pretreatment, but there is still a substantial knowledge gap with respect to the influence of lignin on these cellulose ultrastructural changes. This study was designed to assess how the presence of lignin influences DAP-induced changes in cellulose ultrastructure, which might ultimately have large implications with respect to enzymatic deconstruction efforts. Native, untreated hybrid poplar (Populus trichocarpa x Populus deltoids) samples and a partially delignified poplar sample (facilitated by acidic sodium chlorite pulping) were separately pretreated with dilute sulfuric acid (0.10 M) at 160°C for 15 minutes and 35 minutes, respectively . Following extensive characterization, the partially delignified biomass displayed more significant changes in cellulose ultrastructure following DAP than the native untreated biomass. With respect to the native untreated poplar, delignified poplar after DAP (in which approximately 40% lignin removal occurred) experienced: increased cellulose accessibility indicated by increased Simons’ stain (orange dye) adsorption from 21.8 to 72.5 mg/g, decreased cellulose weight-average degree of polymerization (DPw) from 3087 to 294 units, and increased cellulose crystallite size from 2.9 to 4.2 nm. These changes following DAP ultimately increased enzymatic sugar yield from 10 to 80%. We conclude that, overall, the results indicate a strong influence of lignin content on cellulose ultrastructural changes occurring during DAP. With the reduction of lignin content during DAP, the enlargement of

  17. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean

    2011-01-01

    Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

  18. Alkaline/peracetic acid as a pretreatment of lignocellulosic biomass for ethanol fuel production

    NASA Astrophysics Data System (ADS)

    Teixeira, Lincoln Cambraia

    Peracetic acid is a lignin oxidation pretreatment with low energy input by which biomass can be treated in a silo type system for improving enzymatic digestibility of lignocellulosic materials for ethanol production. Experimentally, ground hybrid poplar wood and sugar cane bagasse are placed in plastic bags and a peracetic acid solution is added to the biomass in different concentrations based on oven-dry biomass. The ratio of solution to biomass is 6:1; after initial mixing of the resulting paste, a seven-day storage period at about 20°C is used in this study. As a complementary method, a series of pre-pretreatments using stoichiometric amounts of sodium hydroxide and ammonium hydroxide based on 4-methyl-glucuronic acid and acetyl content in the biomass is been performed before addition of peracetic acid. The alkaline solutions are added to the biomass in a ratio of 14:1 solution to biomass; the slurry is mixed for 24 hours at ambient temperature. The above procedures give high xylan content substrates. Consequently, xylanase/beta-glucosidase combinations are more effective than cellulase preparations in hydrolyzing these materials. The pretreatment effectiveness is evaluated using standard enzymatic hydrolysis and simultaneous saccharification and cofermentation (SSCF) procedures. Hybrid poplar wood pretreated with 15 and 21% peracetic acid based on oven-dry weight of wood gives glucan conversion yields of 76.5 and 98.3%, respectively. Sugar cane bagasse pretreated with the same loadings gives corresponding yields of 85.9 and 93.1%. Raw wood and raw bagasse give corresponding yields of 6.8 and 28.8%, respectively. The combined 6% NaOH/15% peracetic acid pretreatments increase the glucan conversion yields from 76.5 to 100.0% for hybrid poplar wood and from 85.9 to 97.6% for sugar cane bagasse. Respective ethanol yields of 92.8 and 91.9% are obtained from 6% NaOH/15% peracetic acid pretreated materials using recombinant Zymomonas mobilis CP4/pZB5. Peracetic acid

  19. Detoxification of Corncob Acid Hydrolysate with SAA Pretreatment and Xylitol Production by Immobilized Candida tropicalis

    PubMed Central

    Deng, Li-Hong; Tang, Yong; Liu, Yun

    2014-01-01

    Xylitol fermentation production from corncob acid hydrolysate has become an attractive and promising process. However, corncob acid hydrolysate cannot be directly used as fermentation substrate owing to various inhibitors. In this work, soaking in aqueous ammonia (SAA) pretreatment was employed to reduce the inhibitors in acid hydrolysate. After detoxification, the corncob acid hydrolysate was fermented by immobilized Candida tropicalis cell to produce xylitol. Results revealed that SAA pretreatment showed high delignification and efficient removal of acetyl group compounds without effect on cellulose and xylan content. Acetic acid was completely removed, and the content of phenolic compounds was reduced by 80%. Furthermore, kinetic behaviors of xylitol production by immobilized C. tropicalis cell were elucidated from corncob acid hydrolysate detoxified with SAA pretreatment and two-step adsorption method, respectively. The immobilized C. tropicalis cell showed higher productivity efficiency using the corncob acid hydrolysate as fermentation substrate after detoxification with SAA pretreatment than by two-step adsorption method in the five successive batch fermentation rounds. After the fifth round fermentation, about 60 g xylitol/L fermentation substrate was obtained for SAA pretreatment detoxification, while about 30 g xylitol/L fermentation substrate was obtained for two-step adsorption detoxification. PMID:25133211

  20. Dilute acid pretreatment and enzymatic hydrolysis of sorghum biomass for sugar recovery--a statistical approach.

    PubMed

    Akanksha, Karthik; Prasad, Arjun; Sukumaran, Rajeev K; Nampoothiri, Madhavan; Pandey, Ashok; Rao, S S; Parameswaran, Binod

    2014-11-01

    Sorghum is one of the commercially feasible lignocellulosic biomass and has a great potential of being sustainable feedstock for renewable energy. As with any lignocellulosic biomass, sorghum also requires pretreatment which increases its susceptibility to hydrolysis by enzymes for generating sugars which can be further fermented to alcohol. In the present study, sorghum biomass was evaluated for deriving maximum fermentable sugars by optimizing various pretreatment parameters using statistical optimization methods. Pretreatment studies were done with H2SO4, followed by enzymatic saccharification. The efficiency of the process was evaluated on the basis of production of the total reducing sugars released during the process. Compositional analysis was done for native as well as pretreated biomass and compared. The biomass pretreated with the optimized conditions could yield 0.408 g of reducing sugars /g of pretreated biomass upon enzymatic hydrolysis. The cellulose content in the solid portion obtained after pretreatment using optimised conditions was found to be increased by 43.37% with lesser production of inhibitors in acid pretreated liquor. PMID:25434103

  1. An efficient and green pretreatment to stimulate short-chain fatty acids production from waste activated sludge anaerobic fermentation using free nitrous acid.

    PubMed

    Li, Xiaoming; Zhao, Jianwei; Wang, Dongbo; Yang, Qi; Xu, Qiuxiang; Deng, Yongchao; Yang, Weiqiang; Zeng, Guangming

    2016-02-01

    Short-chain fatty acid (SCFA) production from waste activated sludge (WAS) anaerobic fermentation is often limited by the slow hydrolysis rate and poor substrate availability, thus a long fermentation time is required. This paper reports a new pretreatment approach, i.e., using free nitrous acid (FNA) to pretreat sludge, for significantly enhanced SCFA production. Experimental results showed the highest SCFA production occurred at 1.8 mg FNA/L with time of day 6, which was 3.7-fold of the blank at fermentation time of day 12. Mechanism studies revealed that FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. It was also found that FNA pretreatment benefited hydrolysis and acidification processes but inhibited the activities of methanogens, thereby promoting the yield of SCFA. In addition, the FNA pretreatment substantially stimulated the activities of key enzymes responsible for hydrolysis and acidification, which were consistent with the improvement of solubilization, hydrolysis and acidification of WAS anaerobic fermentation. PMID:26363316

  2. Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology.

    PubMed

    Ávila-Lara, Abimael I; Camberos-Flores, Jesus N; Mendoza-Pérez, Jorge A; Messina-Fernández, Sarah R; Saldaña-Duran, Claudia E; Jimenez-Ruiz, Edgar I; Sánchez-Herrera, Leticia M; Pérez-Pimienta, Jose A

    2015-01-01

    Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

  3. Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology

    PubMed Central

    Ávila-Lara, Abimael I.; Camberos-Flores, Jesus N.; Mendoza-Pérez, Jorge A.; Messina-Fernández, Sarah R.; Saldaña-Duran, Claudia E.; Jimenez-Ruiz, Edgar I.; Sánchez-Herrera, Leticia M.; Pérez-Pimienta, Jose A.

    2015-01-01

    Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

  4. Prognostic significance of pretreatment albumin/globulin ratio in patients with hepatocellular carcinoma

    PubMed Central

    Deng, Yan; Pang, Qing; Miao, Run-Chen; Chen, Wei; Zhou, Yan-Yan; Bi, Jian-Bin; Liu, Su-Shun; Zhang, Jing-Yao; Qu, Kai; Liu, Chang

    2016-01-01

    Background Pretreatment nutritional and immunological statuses play an indispensable role in predicting the outcome of patients with various types of malignancies. The purpose of this study is to evaluate the predictive value of albumin/globulin ratio (AGR) in overall survival (OS) and recurrence in patients with hepatocellular carcinoma (HCC) following radical hepatic carcinectomy. Patients and methods This retrospective study included a total of 172 patients with HCC with complete medical and follow-up information between 2002 and 2012. AGR was calculated according to the following formula: AGR = albumin/globulin. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff value. The associations of AGR with clinicopathological characteristics and prognosis were assessed. Further multivariate analysis using Cox regression model and subgroup analysis was performed to evaluate the predictive value. Results Receiver operating characteristic curve determined 37.65, 31.99, and 1.48 as the optimal cutoff values of albumin, globulin, and AGR in terms of 5-year OS or death, respectively. On the basis of the cutoff value of AGR, all the patients were divided, respectively, into low-AGR (n=105) and high-AGR (n=67) groups. AGR was found to be significantly correlated with age, cancer embolus, international normalized ratio, and postoperative outcome (P<0.05). Hepatitis B virus infection (hazard ratio [HR]: 2.125; 95% confidence interval [CI]: 1.285–3.153), tumor node metastasis stage (HR: 1.656; 95% CI: 1.234–2.223), serum albumin (HR: 0.546; 95% CI: 0.347–0.857), and AGR (HR: 0.402; 95% CI: 0.233–0.691) were independent predictors of OS via univariate and multivariate survival analyses. However, alpha-fetoprotein (HR: 1.708; 95% CI: 1.027–2.838), tumor node metastasis stage (HR: 1.464; 95% CI: 1.078–1.989), and AGR (HR: 0.493; 95% CI: 0.293–0.828) functioned as independent risk variables for predicting recurrence. Moreover

  5. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dilute H3PO4 (0.0 - 2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using a central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzym...

  6. Pretreatment with memantine prevents Alzheimer-like alterations induced by intrahippocampal okadaic acid administration in rats.

    PubMed

    Zimmer, Eduardo Rigon; Kalinine, Eduardo; Haas, Clarissa Branco; Torrez, Vitor Rocco; Souza, Diogo Onofre; Muller, Alexandre Pastoris; Portela, Luis Valmor

    2012-12-01

    Cerebral okadaic acid (OA) administration induces Alzheimer's disease (AD)-like phenotype in rats. Alterations in glutamate levels associated with hyperactivation of cyclin dependent kinase 5 (Cdk5) signaling pathway downstream Tau phosphorylation may participate in the genesis of this pathological phenotype. Here, we examined the efficacy of memantine (MN) pretreatment on reducing OA-induced AD-like phenotypes in rats. Wistar rats were given daily intraperitoneal injections of MN for 3 days and then given an intrahippocampal infusion of OA. Animals were divided into four groups: control (CO), MN, OA and MN/OA. Spontaneous locomotion and spatial memory performance were assessed by open field and Morris water maze respectively. Additionally, we measured glutamate levels in the cerebrospinal fluid (CSF) and the immunocontent of Cdk5, p35, p25 and phosphorylated Tau (pTauSer199/202) in the hippocampus. Spontaneous locomotion did not differ between groups. The OA group showed a significant decrease in spatial memory performance compared to all groups. The OA infusion also increased CSF glutamate levels and the immunocontents of Cdk5, p25 and pTauSer199/202 in the hippocampus. Conversely, pretreatment with MN prevented OA-induced spatial memory deficits and the increment of CSF glutamate level; which paralleled with normal immunocontents of Cdk5, p25 and pTau- Ser199/202 proteins. There were positive correlations between spatial memory performance and the neurochemical parameters. In summary, pretreatment with MN prevents spatial memory deficits induced by intrahippocampal OA administration in rats. The prevention of increase CSF glutamate levels, along with the reduced hippocampal phosphorylation of TauSer199/202 by Cdk5/p25 signaling pathway, are the mechanisms proposed to participate in the prophylactic effects of MN in this AD-like model. PMID:22515493

  7. Effect of nitric acid on pretreatment and fermentation for enhancing ethanol production of rice straw.

    PubMed

    Kim, Ilgook; Lee, Bomi; Park, Ji-Yeon; Choi, Sun-A; Han, Jong-In

    2014-01-01

    In this study, nitric acid (HNO₃) was evaluated as an acid catalyst for rice straw pretreatment, and, after neutralization, as a sole nitrogen source for subsequent fermentation. Response surface methodology was used to obtain optimal pretreatment condition with respect to HNO₃ concentration (0.2-1.0%), temperature (120-160 °C) and reaction time (1-20 min). In a condition of 0.65% HNO₃, 158.8 °C and 5.86 min, a maximum xylose yield of 86.5% and an enzymatic digestibility of 83.0% were achieved. The sugar solution that contained nitrate derived from the acid catalyst supported the enhancement of ethanol yield by Pichia stipitis from 10.92 g/L to 14.50 g/L. The results clearly reveal that nitric acid could be used not only as a pretreatment catalyst, but also as a nitrogen source in the fermentation process for bioethanol production. It is anticipated that the HNO₃-based pretreatment can reduce financial burden on the cellulosic bioethanol industry by simplifying after-pretreatment-steps as well as providing a nitrogen source. PMID:24274544

  8. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    SciTech Connect

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-25

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD)

  9. The effect of acid hydrolysis pretreatment on crystallinity and solubility of kenaf cellulose membrane

    NASA Astrophysics Data System (ADS)

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad

    2015-09-01

    Cellulose was extracted from kenaf core pulp (KCP) by series of bleaching steps in the sequence (DEED) where D and E are referred as acid and alkali treatment. The bleached kenaf pulp (BKCP) is then pretreated with acid hydrolysis at room temperature for 1 and 3 h respectively. The pretreated cellulose is dissolved in lithium hydroxide/urea (LiOH/urea) and cellulose solution produced was immersed in distilled water bath. BKCP without treatment was also conducted for comparison purpose. The effects of acid hydrolysis pretreatment on solubility and crystallinity are investigated. Higher solubility of cellulose solution is achieved for treated samples. Cellulose II formation and crystallinity index of the cellulose membrane were determined by X-ray diffraction (XRD).

  10. Enhancement of sludge anaerobic biodegradability by combined microwave-H2O2 pretreatment in acidic conditions.

    PubMed

    Eswari, Parvathy; Kavitha, S; Kaliappan, S; Yeom, Ick-Tae; Banu, J Rajesh

    2016-07-01

    The aim of this study was to increase the sludge disintegration and reduce the cost of microwave (MW) pretreatment. Thermodynamic analysis of MW hydrolysis revealed the best fit with a first-order kinetic model at a specific energy of 18,600 kJ/kg total solids (TS). Combining H2O2 with MW resulted in a significant increment in solubilization from 30 to 50 % at 18,600 kJ/kg TS. The pH of H2O2-assisted MW-pretreated sludge (MW + H2O2) was in the alkaline range (pH 9-10), and it made the sludge unfavorable for subsequent anaerobic digestion and inhibits methane production. In order to nullify the alkaline effect caused by the MW + H2O2 combination, the addition of acid was considered for pH adjustment. H2O2-assisted MW-pretreated sludge in acidic conditions (MW + H2O2 + acid) showed a maximum methane production of 323 mL/g volatile solids (VS) than others during anaerobic biodegradability. A cost analysis of this study reveals that MW + H2O2 + acid was the most economical method with a net profit of 59.90 €/t of sludge. PMID:27026550

  11. Co-hydrolysis of hydrothermal and dilute acid pretreated populus slurries to support development of a high-throughput pretreatment system

    PubMed Central

    2011-01-01

    Background The BioEnergy Science Center (BESC) developed a high-throughput screening method to rapidly identify low-recalcitrance biomass variants. Because the customary separation and analysis of liquid and solids between pretreatment and enzymatic hydrolysis used in conventional analyses is slow, labor-intensive and very difficult to automate, a streamlined approach we term 'co-hydrolysis' was developed. In this method, the solids and liquid in the pretreated biomass slurry are not separated, but instead hydrolysis is performed by adding enzymes to the whole pretreated slurry. The effects of pretreatment method, severity and solids loading on co-hydrolysis performance were investigated. Results For hydrothermal pretreatment at solids concentrations of 0.5 to 2%, high enzyme protein loadings of about 100 mg/g of substrate (glucan plus xylan) in the original poplar wood achieved glucose and xylose yields for co-hydrolysis that were comparable with those for washed solids. In addition, although poplar wood sugar yields from co-hydrolysis at 2% solids concentrations fell short of those from hydrolysis of washed solids after dilute sulfuric acid pretreatment even at high enzyme loadings, pretreatment at 0.5% solids concentrations resulted in similar yields for all but the lowest enzyme loading. Conclusions Overall, the influence of severity on susceptibility of pretreated substrates to enzymatic hydrolysis was clearly discernable, showing co-hydrolysis to be a viable approach for identifying plant-pretreatment-enzyme combinations with substantial advantages for sugar production. PMID:21749707

  12. Production of Cellulose-Hydrogen from Corn Stalk based on Acid-enzyme Two-Stage Pretreatment by Mixed Culture

    NASA Astrophysics Data System (ADS)

    Xing, Y.; Fan, Y. T.; Hou, H. W.

    2010-03-01

    Production of cellulose-hydrogen from corn stalk based on acid-enzyme two-stage pretreatment by lesser panda manure was carried out in batch tests. The acid-enzyme two-stage pretreatment of corn stalk was found most effective, in which the yields of soluble saccharides (SS) were 470 mg/g-TS. The maximum cumulative H2 yield (165.8 ml H2/g-TS) and H2 production rate (12.8 ml H2/g-TS h-1) were obtained at pH 5.5, 36 °C by treating a substrate of 15 g/L. The hydrogen content in biogas was 57.0% and there was no significant methane gas observed.

  13. Pretreatment of Sugar Beet Pulp with Dilute Sulfurous Acid is Effective for Multipurpose Usage of Carbohydrates.

    PubMed

    Kharina, M; Emelyanov, V; Mokshina, N; Ibragimova, N; Gorshkova, T

    2016-05-01

    Sulfurous acid was used for pretreatment of sugar beet pulp (SBP) in order to achieve high efficiency of both extraction of carbohydrates and subsequent enzymatic hydrolysis of the remaining solids. The main advantage of sulfurous acid usage as pretreatment agent is the possibility of its regeneration. Application of sulfurous acid as hydrolyzing agent in relatively low concentrations (0.6-1.0 %) during a short period of time (10-20 min) and low solid to liquid ratio (1:3, 1:6) allowed effective extraction of carbohydrates from SBP and provided positive effect on subsequent enzymatic hydrolysis. The highest obtained concentration of reducing substances (RS) in hydrolysates was 8.5 %; up to 33.6 % of all carbohydrates present in SBP could be extracted. The major obtained monosaccharides were arabinose and glucose (9.4 and 7.3 g/l, respectively). Pretreatment of SBP with sulfurous acid increased 4.6 times the yield of glucose during subsequent enzymatic hydrolysis of remaining solids with cellulase cocktail, as compared to the untreated SBP. Total yield of glucose during SBP pretreatment and subsequent enzymatic hydrolysis amounted to 89.4 % of the theoretical yield. The approach can be applied directly to the wet SBP. Hydrolysis of sugar beet pulp with sulfurous acid is recommended for obtaining of individual monosaccharides, as well as nutritional media. PMID:26821256

  14. Effect of fungal and phosphoric acid pretreatment on ethanol production from oil palm empty fruit bunches (OPEFB).

    PubMed

    Ishola, Mofoluwake M; Isroi; Taherzadeh, Mohammad J

    2014-08-01

    Oil palm empty fruit bunches (OPEFB), a lignocellulosic residue of palm oil industries was examined for ethanol production. Milled OPEFB exposed to simultaneous saccharification and fermentation (SSF) with enzymes and Saccharomyces cerevisiae resulted just in 14.5% ethanol yield compared to the theoretical yield. Therefore, chemical pretreatment with phosphoric acid, a biological pretreatment with white-rot fungus Pleurotus floridanus, and their combination were carried out on OPEFB prior to the SSF. Pretreatment with phosphoric acid, combination of both methods and just fungal pretreatment improved the digestibility of OPEFB by 24.0, 16.5 and 4.5 times, respectively. During the SSF, phosphoric acid pretreatment, combination of fungal and phosphoric acid pretreatment and just fungal pretreatment resulted in the highest 89.4%, 62.8% and 27.9% of the theoretical ethanol yield, respectively. However, the recovery of the OPEFB after the fungal pretreatment was 98.7%, which was higher than after phosphoric acid pretreatment (36.5%) and combined pretreatment (45.2%). PMID:24630370

  15. Effects of pretreatment with simulated acid rain on the severity of dogwood anthracnose

    SciTech Connect

    Britton, K.O.; Berrang, P.; Mavity, E.

    1996-06-01

    The effects of simulated acid rain on dogwood anthracnose severity were evaluated in a series of greenhouse and field experiments over a 4-year period. In 1990 and 1991, Cornus florida seedlings received 10 weekly foliar applications of simulated rain adjusted to pH 2.5, 3.5, 4.5, and 5.5. They were then placed under mature dogwoods naturally infected with Discula destructive. In both years, the percent leaf area infected increased significantly as the pH of the simulated rain solution decreased. In 1992 and 1993, seedlings were wrapped in plastic bags below the root collar to permit separate application of simulated acid rain (pH 2.5) or normal rain (pH 5.5) to the foliage or the growing medium or both. Application of pH 2.5 rain to the growing medium increased disease severity. Foliar applications alone did not increase disease. These results suggest that changes in nutrient availability, rather than foliar damage, are responsible for the increase in anthracnose severity in dogwoods pretreated with simulated acid rain. 41 refs., 1 fig., 1 tab.

  16. High titer gluconic acid fermentation by Aspergillus niger from dry dilute acid pretreated corn stover without detoxification.

    PubMed

    Zhang, Hongsen; Zhang, Jian; Bao, Jie

    2016-03-01

    This study reported a high titer gluconic acid fermentation using dry dilute acid pretreated corn stover (DDAP) hydrolysate without detoxification. The selected fermenting strain Aspergillus niger SIIM M276 was capable of inhibitor degradation thus no detoxification on pretreated corn stover was required. Parameters of gluconic acid fermentation in corn stover hydrolysate were optimized in flasks and in fermentors to achieve 76.67 g/L gluconic acid with overall yield of 94.91%. The sodium gluconate obtained from corn stover was used as additive for extending setting time of cement mortar and similar function was obtained with starch based sodium gluconate. This study provided the first high titer gluconic acid production from lignocellulosic feedstock with potential of industrial applications. PMID:26724553

  17. A feasibility study on the multistage process for the oxalic acid pretreatment of a lignocellulosic biomass using electrodialysis.

    PubMed

    Lee, Hong-Joo; Ahn, Sung Ju; Seo, Young-Jun; Lee, Jae-Won

    2013-02-01

    The present study investigated the feasibility of the recovery and reuse oxalic acid in a multistage process for the pretreatment of a lignocellulosic biomass. Electrodialysis (ED), an electrochemical process using ion exchange membranes, was used to recover and reuse oxalic acid in the multistage process. The ED optimal condition for recover oxalic acid was potential of 10V and pH 2.2 in synthetic solutions. The recovery efficiency of oxalic acid from hydrolysates reached 100% at potential of 10V. The power consumption to treat 1mol of oxalic acid was estimated to be 41.0wh. At the same time, ethanol production increased up to 19g/L in the ED-treated hydrolysate, corresponding to ethanol productivity of 0.27g/L/h. It was clearly shown that bioethanol fermentation efficiency increased using the ED process, due to a small loss of fermentable sugar and a significantly high removal of inhibitory chemicals. PMID:23306131

  18. Pretreatment of banana agricultural waste for bio-ethanol production: individual and interactive effects of acid and alkali pretreatments with autoclaving, microwave heating and ultrasonication.

    PubMed

    Gabhane, Jagdish; William, S P M Prince; Gadhe, Abhijit; Rath, Ritika; Vaidya, Atul Narayan; Wate, Satish

    2014-02-01

    Banana agricultural waste is one of the potential lignocellulosic substrates which are mostly un-utilized but sufficiently available in many parts of the world. In the present study, suitability of banana waste for biofuel production with respect to pretreatment and reducing sugar yield was assessed. The effectiveness of both acid and alkali pretreatments along with autoclaving, microwave heating and ultrasonication on different morphological parts of banana (BMPs) was studied. The data were statistically analyzed using ANOVA and numerical point prediction tool of MINITAB RELEASE 14. Accordingly, the optimum cumulative conditions for maximum recovery of reducing sugar through acid pretreatment are: leaf (LF) as the substrate with 25 min of reaction time and 180°C of reaction temperature using microwave. Whereas, the optimum conditions for alkaline pretreatments are: pith (PH) as the substrate with 51 min of reaction time and 50°C of reaction temperature using ultrasonication (US). PMID:24268472

  19. Use of Cupriavidus basilensis-aided bioabatement to enhance fermentation of acid-pretreated biomass hydrolysates by Clostridium beijerinckii.

    PubMed

    Agu, Chidozie Victor; Ujor, Victor; Gopalan, Venkat; Ezeji, Thaddeus Chukwuemeka

    2016-09-01

    Lignocellulose-derived microbial inhibitors (LDMICs) prevent efficient fermentation of Miscanthus giganteus (MG) hydrolysates to fuels and chemicals. To address this problem, we explored detoxification of pretreated MG biomass by Cupriavidus basilensis ATCC(®)BAA-699 prior to enzymatic saccharification. We document three key findings from our test of this strategy to alleviate LDMIC-mediated toxicity on Clostridium beijerinckii NCIMB 8052 during fermentation of MG hydrolysates. First, we demonstrate that growth of C. basilensis is possible on furfural, 5-hydroxymethyfurfural, cinnamaldehyde, 4-hydroxybenzaldehyde, syringaldehyde, vanillin, and ferulic, p-coumaric, syringic and vanillic acid, as sole carbon sources. Second, we report that C. basilensis detoxified and metabolized ~98 % LDMICs present in dilute acid-pretreated MG hydrolysates. Last, this bioabatement resulted in significant payoffs during acetone-butanol-ethanol (ABE) fermentation by C. beijerinckii: 70, 50 and 73 % improvement in ABE concentration, yield and productivity, respectively. Together, our results show that biological detoxification of acid-pretreated MG hydrolysates prior to fermentation is feasible and beneficial. PMID:27400988

  20. High ethanol fermentation performance of the dry dilute acid pretreated corn stover by an evolutionarily adapted Saccharomyces cerevisiae strain.

    PubMed

    Qureshi, Abdul Sattar; Zhang, Jian; Bao, Jie

    2015-01-01

    Ethanol fermentation was investigated at the high solids content of the dry dilute sulfuric acid pretreated corn stover feedstock using an evolutionary adapted Saccharomyces cerevisiae DQ1 strain. The evolutionary adaptation was conducted by successively transferring the S. cerevisiae DQ1 cells into the inhibitors containing corn stover hydrolysate every 12h and finally a stable yeast strain was obtained after 65 days' continuous adaptation. The ethanol fermentation performance using the adapted strain was significantly improved with the high ethanol titer of 71.40 g/L and the high yield of 80.34% in the simultaneous saccharification and fermentation (SSF) at 30% solids content. No wastewater was generated from pretreatment to fermentation steps. The results were compared with the published cellulosic ethanol fermentation cases, and the obvious advantages of the present work were demonstrated not only at the high ethanol titer and yield, but also the significant reduction of wastewater generation and potential cost reduction. PMID:25930238

  1. High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...

  2. Comparison of Dilute Acid and Ionic Liquid Pretreatment of Switchgrass: Biomass Recalcitrance, Delignification and Enzymatic Saccharification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatme...

  3. Combined Effect of Free Nitrous Acid Pretreatment and Sodium Dodecylbenzene Sulfonate on Short-Chain Fatty Acid Production from Waste Activated Sludge

    PubMed Central

    Zhao, Jianwei; Liu, Yiwen; Ni, Bingjie; Wang, Qilin; Wang, Dongbo; Yang, Qi; Sun, Yingjie; Zeng, Guangming; Li, Xiaoming

    2016-01-01

    Free nitrous acid (FNA) serving as a pretreatment is an effective approach to accelerate sludge disintegration. Also, sodium dodecylbenzene sulfonate (SDBS), a type of surfactants, has been determined at significant levels in sewage sludge, which thereby affects the characteristics of sludge. Both FNA pretreatment and sludge SDBS levels can affect short-chain fatty acid (SCFA) generation from sludge anaerobic fermentation. To date, however, the combined effect of FNA pretreatment and SDBS presence on SCFA production as well as the corresponding mechanisms have never been documented. This work therefore aims to provide such support. Experimental results showed that the combination of FNA and SDBS treatment not only improved SCFA accumulation but also shortened the fermentation time. The maximal SCFA accumulation of 334.5 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) was achieved at 1.54 mg FNA/L treatment and 0.02 g/g dry sludge, which was respectively 1.79-fold and 1.41-fold of that from FNA treatment and sludge containing SDBS alone. Mechanism investigations revealed that the combined FNA pretreatment and SDBS accelerated solubilization, hydrolysis, and acidification steps but inhibited the methanogenesis. All those observations were in agreement with SCFA enhancement. PMID:26868898

  4. Combined Effect of Free Nitrous Acid Pretreatment and Sodium Dodecylbenzene Sulfonate on Short-Chain Fatty Acid Production from Waste Activated Sludge.

    PubMed

    Zhao, Jianwei; Liu, Yiwen; Ni, Bingjie; Wang, Qilin; Wang, Dongbo; Yang, Qi; Sun, Yingjie; Zeng, Guangming; Li, Xiaoming

    2016-01-01

    Free nitrous acid (FNA) serving as a pretreatment is an effective approach to accelerate sludge disintegration. Also, sodium dodecylbenzene sulfonate (SDBS), a type of surfactants, has been determined at significant levels in sewage sludge, which thereby affects the characteristics of sludge. Both FNA pretreatment and sludge SDBS levels can affect short-chain fatty acid (SCFA) generation from sludge anaerobic fermentation. To date, however, the combined effect of FNA pretreatment and SDBS presence on SCFA production as well as the corresponding mechanisms have never been documented. This work therefore aims to provide such support. Experimental results showed that the combination of FNA and SDBS treatment not only improved SCFA accumulation but also shortened the fermentation time. The maximal SCFA accumulation of 334.5 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) was achieved at 1.54 mg FNA/L treatment and 0.02 g/g dry sludge, which was respectively 1.79-fold and 1.41-fold of that from FNA treatment and sludge containing SDBS alone. Mechanism investigations revealed that the combined FNA pretreatment and SDBS accelerated solubilization, hydrolysis, and acidification steps but inhibited the methanogenesis. All those observations were in agreement with SCFA enhancement. PMID:26868898

  5. Acid pre-treatment method for in situ ore leaching

    DOEpatents

    Mallon, R.G.; Braun, R.L.

    1975-10-28

    An acid leaching method is described for the recovery of a desired element from a subterranean rubblized body of primary ore containing the element and also having associated therewith a carbonate mineral wherein the rubblized ore body is flooded with an aqueous acidic solution in order to release carbon dioxide from the associated carbonate mineral. After a substantial portion of the available carbon dioxide is released and removed from the ore body, as by venting to the atmosphere, an oxidizing gas is introduced into the flooded, rubblized ore to oxidize the ore and form an acid leach solution effective in the presence of the dissolved oxidizing gas to dissolve the ore and cause the desired element to go into solution. The leach solution is then circulated to the surface where the metal values are recovered therefrom.

  6. Whole slurry fermentation of maleic acid-pretreated oil palm empty fruit bunches for ethanol production not necessitating a detoxification process.

    PubMed

    Jung, Young Hoon; Kim, In Jung; Kim, Hyun Kyung; Kim, Kyoung Heon

    2014-04-01

    The yield of ethanol from oil palm empty fruit bunches (EFB) was increased on exploiting maleic acid pretreatment combined with fermentation of the pretreated whole slurry. The optimized conditions for pretreatment were to expose EFB to a high temperature (190 °C) with 1 % (w/v) maleic acid for a short time duration (3 min ramping to the set temperature with no holding) in a microwave digester. An enzymatic digestibility of 60.9 % (based on theoretical glucose yield) was exhibited using pretreated and washed EFB after 48 h of hydrolysis. Simultaneous saccharification and fermentation (SSF) of the whole slurry of pretreated EFB for 48 h resulted in 61.3 % theoretical yield of ethanol based on the initial amount of glucan in untreated EFB. These results indicate that maleic acid is a suitable catalyst not requiring detoxification steps for whole slurry fermentation of EFB for ethanol production, thus improving the process economics. Also, the whole slurry fermentation can significantly increase the biomass utilization by converting sugar from both solid and liquid phases of the pretreated slurry. PMID:23982450

  7. Effect of L-ascorbic acid pretreatment on cadmium toxicity in the male Fischer (F344/NCr) rat.

    PubMed

    Shiraishi, N; Uno, H; Waalkes, M P

    1993-12-31

    Some studies have indicated that cadmium-induced lethality and selective injurious effects to specific tissues, such as testes or liver, can be prevented by pretreatment with the antioxidant L-ascorbic acid (ascorbic acid). However, the basis of this tolerance is unclear. We examined the effects of ascorbic acid pretreatment on cadmium toxicity in male Fischer (F344/NCr) rats. Cadmium treatment alone (25 mumol CdCl2/kg, s.c.) proved lethal, causing a 93% mortality within 72 h, but in rats pretreated with ascorbic acid (2 g/kg, s.c. 24, 12 and 1 h) cadmium-induced lethality was nearly prevented. Hepatic lesions, including hepatocellular necrosis, induced by cadmium were at least partially ameliorated by ascorbic acid pretreatment. Ascorbic acid pretreatment had no effect on cadmium-induced testicular lesions nor on cadmium content in testes, liver, kidney and urine. Ascorbic acid alone modestly increased hepatic metallothionein (MT), but not renal MT and had no effect on induction of hepatic or renal MT by cadmium. In contrast to liver and kidney, testicular cadmium-binding protein (TCBP) in rats exposed to cadmium alone decreased markedly. Moreover, the level of TCBP decreased unexpectedly in ascorbic acid pretreated rats as compared with control. These results indicate that ascorbic acid pretreatment decreases the toxicity of cadmium in the rat without markedly modifying its toxicokinetics or markedly stimulating MT synthesis. PMID:8303714

  8. Effectiveness of coagulation and acid precipitation processes for the pre-treatment of diluted black liquor.

    PubMed

    Garg, Anurag; Mishra, I M; Chand, S

    2010-08-15

    The effectiveness of coagulation (using aluminium-based chemicals and ferrous sulfate) and acid precipitation (using H(2)SO(4)) processes for the pre-treatment of diluted black liquor obtained from a pulp and paper mill is reported. Commercial alum was found to be the most economical among all the aluminium and ferrous salts used as a coagulant. A maximum removal of chemical oxygen demand (COD) (ca. 63%) and colour reduction (ca. 90%) from the wastewater (COD = 7000 mg l(-1)) at pH 5.0 was obtained with alum. During the acid precipitation process, at pH < 5.0, significant COD reductions (up to 64%) were observed. Solid residue obtained from the alum treatment at a temperature of 95 degrees C showed much better (3 times) settling rate than that for the residue obtained after treatment with the same coagulant at a temperature of 25 degrees C. The settling curves had three parts, namely, hindered, transition and compression zones. Tory plots were used to determine the critical height of suspension-supernatant interface that is used in the design of a clarifier-thickener unit. High heating values and large biomass fraction of the solid residues can encourage the fuel users to use this waste derived sludge as a potential renewable energy source. PMID:20430523

  9. Enzymatic saccharification and lactic acid production from banana pseudo-stem through optimized pretreatment at lowest catalyst concentration

    PubMed Central

    Idrees, Muhammad; Adnan, Ahmad; Malik, Farnaz; Qureshi, Fahim Ashraf

    2013-01-01

    This work estimates the potential of banana pseudo-stem with high cellulosic content 42.2-63 %, for the production of fermentable sugars for lactic acid production through statistically optimized pretreatment method. To evaluate the catalyzed pretreatment efficiency of banana pseudo stem based on the enzymatic digestibility, Response Surface Methodology (RSM) was employed for the optimization of pretreatment temperature and time using lowest concentrations of H2SO4, NaOH, NaOH catalyzed Na2S and Na2SO3 that seemed to be significant variables with P<0.05. High F and R2 values and low p-value for hydrolysis yield indicated the model predictability. The optimized condition for NaOH was determined to be conc. 1 %, temperature 130 oC for 2.6 hr; Na2S; conc. 1 %, temperature 130 oC for 2.29 hr; Na2SO3; conc. 1 %, temperature 130 oC for 2.41 hr and H2SO4; conc. 1 %, temperature 129.45 oC for 2.18 hr, produced 84.91 %, 85.23 %, 81.2 % and 76.02 % hydrolysis yield, respectively. Sulphuric acid provided 33+1 gL-1 reducing sugars in pretreatment step along with 38+0.5 gL-1 during enzymatic hydrolysis. Separate hydrolysis and fermentation of resulting sugars showed that the conversion of glucans into lactic acid reached 92 % of the theoretical yield of glucose. PMID:26966423

  10. Pretreatment of corn stover for sugar production using a two-stage dilute acid followed by wet-milling pretreatment process.

    PubMed

    Liu, Qiyu; Li, Wenzhi; Ma, Qiaozhi; An, Shengxin; Li, Minghao; Jameel, Hasan; Chang, Hou-Min

    2016-07-01

    A two-stage process was evaluated to increase sugar recovery. Firstly, corn stover was treated with dilute hydrochloric acid to recover the xylose, and then the residue was subjected to a wet-milling pretreatment. Dilute hydrochloric acid showed a high xylose recovery during the first stage. The optimal condition was 120°C and 40min for 0.7wt% dilute hydrochloric acid pretreatment followed by wet-milling pretreatment for 15min. The xylose and glucose yield were 81.0% and 64.0%, respectively, with a cellulase dosage at 3FPU/g of substrate. This two-stage process was effective on account of the removal of hemicelluloses in the first stage and the delamination of cell wall in the second stage, increasing the possibility of adsorption of cellulose to enzymes, and resulting in a high sugar recovery with a very low enzyme loading. PMID:27035475

  11. Augmented digestion of lignocellulose by steam explosion, acid and alkaline pretreatment methods: a review.

    PubMed

    Singh, Joginder; Suhag, Meenakshi; Dhaka, Anil

    2015-03-01

    Lignocellulosic materials can be explored as one of the sustainable substrates for bioethanol production through microbial intervention as they are abundant, cheap and renewable. But at the same time, their recalcitrant structure makes the conversion process more cumbersome owing to their chemical composition which adversely affects the efficiency of bioethanol production. Therefore, the technical approaches to overcome recalcitrance of biomass feedstock has been developed to remove the barriers with the help of pretreatment methods which make cellulose more accessible to the hydrolytic enzymes, secreted by the microorganisms, for its conversion to glucose. Pretreatment of lignocellulosic biomass in cost effective manner is a major challenge to bioethanol technology research and development. Hence, in this review, we have discussed various aspects of three commonly used pretreatment methods, viz., steam explosion, acid and alkaline, applied on various lignocellulosic biomasses to augment their digestibility alongwith the challenges associated with their processing. PMID:25498680

  12. Enhanced bioethanol production from yellow poplar by deacetylation and oxalic acid pretreatment without detoxification.

    PubMed

    Kundu, Chandan; Lee, Hong-Joo; Lee, Jae-Won

    2015-02-01

    In order to produce ethanol from yellow poplar, deacetylation was performed using sodium hydroxide (NaOH). Optimal deacetylation conditions were determined by a response surface methodology. The highest acetic acid concentration obtained was 7.06 g/L when deacetylation was performed at 60 °C for 80 min with 0.8% NaOH. Acetic acid was recovered by electrodialysis from the deacetylated hydrolysate. The oxalic acid pretreatment of deacetylated biomass was carried out and the hydrolysate directly used for ethanol production without detoxification. Ethanol yields ranged from 0.34 to 0.47 g/g and the highest ethanol yield was obtained when pretreatment was carried out at 150 °C with 50 mM oxalic acid. The highest ethanol concentration obtained from pretreated biomass was 27.21 g/L at 170 °C, using a 50 mM of oxalic acid for the simultaneous saccharification and fermentation (SSF). Overall, 20.31 g of ethanol was obtained by hydrolysate and SSF from 100 g of deacetylated yellow poplar. PMID:25205056

  13. Hydrodechlorination of Silicon Tetrachloride to Trichlorosilane Over Ordered Mesoporous Carbon Catalysts: Effect of Pretreatment of Oxygen and Hydrochloric Acid.

    PubMed

    Kwak, Do-Hwan; Akhtar, M Shaheer; Kim, Ji Man; Yang, O Bong

    2016-02-01

    This paper reports on the catalytic reaction for the conversion of silicon tetrachloride (STC) to trichlorosilane (TCS) over pretreated ordered mesoporous carbon (OMC) catalysts by oxygen (denoted as OMC-O2) and hydrochloric acid (denoted as OMC-HCl) at 300 degrees C under N2 atmosphere. The OMC-O2 shows significantly improved the surface area (1341.2 m2/g) and pore volume (1.65 cm3/g), which results in the highest conversion rate of 7.3% as compared to bare OMC (4.3%) and OMC-HCI (5.7%). It is found that the conversion rate of STC to TCS is proportional to the number of Si-O bond over OMC catalysts, which suggests that Si-O-C bond formation is crucial to the reaction as active sites. The O2 pretreatment seems to promote the generation of oxygenated species for the formation of Si-O-C. PMID:27433674

  14. Pretreatment whole blood Epstein-Barr virus-DNA is a significant prognostic marker in patients with Hodgkin lymphoma.

    PubMed

    Park, Ji Hyun; Yoon, Dok Hyun; Kim, Shin; Park, Jung Sun; Park, Chan-Sik; Sung, Heungsup; Lee, Sang-Wook; Huh, Jooryung; Suh, Cheolwon

    2016-04-01

    Epstein-Barr virus (EBV) in the peripheral blood has become a significant predictor of clinical outcomes in EBV-associated Hodgkin lymphoma (HL). However, due to its relative rarity, prevalence and prognostic role of circulating EBV-DNA has not been well established in Asian patients. Seventy patients with newly diagnosed HL were prospectively registered between October 2007 and January 2013, and underwent pretreatment whole blood (WB) EBV-DNA quantitation using real-time polymerase chain reaction (RT-PCR). WB EBV-DNA in baseline and serial RT-PCR within 1 year were investigated. Clinicopathologic parameters of the patients according to pretreatment WB EBV-DNA were also explored. Twelve patients (17.1 %) demonstrated WB EBV-DNA(+), which was significantly associated to older age, advanced stages, frequent involvements of extranodal sites, low serum albumin and hemoglobin levels, and high international prognostic scores ≥2. Three-year event-free survival (EFS) and overall survival (OS) were significantly inferior in patients with pretreatment WB EBV-DNA(+) (53.5 vs 67.0 and 65.6 vs 90.2 %) (p < 0.032 and <0.01). Negatively conversed EBV-DNA within 1 year after chemotherapy also significantly affected favorable EFS (p < 0.01). Taken together, pretreatment WB EBV-DNA(+) may be a significant predictor of inferior EFS and OS over EBV-encoded RNA in situ hybridization (EBER-ISH)(+) in Korean patients with HL. Serial EBV-DNA monitoring following chemotherapy also seems helpful to predict survival outcomes. PMID:26883027

  15. Progressive deconstruction of Arundo donax Linn. to fermentable sugars by acid catalyzed ionic liquid pretreatment.

    PubMed

    You, Ting-Ting; Zhang, Li-Ming; Xu, Feng

    2016-01-01

    Acid enhanced ionic liquid (IL) 1-n-butyl-3-methylimidazolium chloride ([C4 mim]Cl) pretreatment has shown great potential for boosting the yield of sugars from biomass cost-effectively and environmental-friendly. Pretreatment with shorter processing time will promote the commercial viability. In this work, pretreatment of reduced Amberlyst catalysis time of 34 min was demonstrated to be the most effective among time-varying pretreatments, evidenced by partial removal of hemicellulose and cellulose crystal transformation of Arundo donax Linn. A higher fermentable sugar concentration of 10.42 g/L (2% substrate) was obtained after 72 h of saccharification than the others. Total processing time to reach 92% glucose yield was cut down to approximately 26 h. Progressive deconstruction of crop cell wall was occurred with increased catalysis time by gradual releasing of H3O(+) of Amberlyst. However, vast lignin re-deposited polymers on fibers could hinder further enzymatic hydrolysis. These discoveries provide new insights into a more economic pretreatment for bioethanol production. PMID:26363822

  16. Enhancement of biomass conversion in catalytic fast pyrolysis by microwave-assisted formic acid pretreatment.

    PubMed

    Feng, Yu; Li, Guangyu; Li, Xiangyu; Zhu, Ning; Xiao, Bo; Li, Jian; Wang, Yujue

    2016-08-01

    This study investigated microwave-assisted formic acid (MW-FA) pretreatment as a possible way to improve aromatic production from catalytic fast pyrolysis (CFP) of lignocellulosic biomass. Results showed that short duration of MW-FA pretreatment (5-10min) could effectively disrupt the recalcitrant structure of beech wood and selectively remove its hemicellulose and lignin components. This increased the accessibility of cellulose component of biomass to subsequent thermal conversion in CFP. Consequently, the MW-FA pretreated beech wood produced 14.0-28.3% higher yields (26.4-29.8C%) for valuable aromatic products in CFP than the untreated control (23.2C%). In addition, the yields of undesired solid residue (char/coke) decreased from 33.1C% for the untreated control to 28.6-29.8C% for the MW-FA pretreated samples. These results demonstrate that MW-FA pretreatment can provide an effective way to improve the product distribution from CFP of lignocellulose. PMID:27176672

  17. Effect of pretreatment with carbonic acid on 'Hypercoal' (ash-free coal) production from low-rank coals

    SciTech Connect

    Kensuke Masaki; Nao Kashimura; Toshimasa Takanohashi; Shinya Sato; Akimitsu Matsumura; Ikuo Saito

    2005-10-01

    The use of 'HyperCoal' (ash-free coal) as feedstock for gas turbines results in higher net power output with lower CO{sub 2} emissions. HyperCoal can be produced by thermal extraction from low-rank coals with industrial organic solvents in an inert atmosphere, providing raw materials. The pretreatment of low-rank coals with carbonic acid (CO{sub 2} dissolved in water - CO{sub 2}/H{sub 2}O) produced a strong increase in HyperCoal yields at relatively lower CO{sub 2} pressures of 0.1-0.5 MPa; the thermal extraction yields at 360{sup o}C increased by 7%-15% with extraction yields of 52% and 45% obtained for Wyodak sub-bituminous coal and Beulah-Zap lignite, respectively. In the range of 320-360{sup o}C, crude methylnaphthalene oil (CMNO) extraction yields of pretreated Wyodak coal increased significantly (by 4%-11%) over those of raw coal. The enhanced extraction yields of these low-rank coals are attributed to disruption of cation-bridging crosslinks on acid pretreatment, and the release of the hydrogen bonds by CMNO extraction. 18 refs., 4 figs., 4 tabs.

  18. Ursodeoxycholic acid pretreatment reduces oral bioavailability of the multiple drug resistance-associated protein 2 substrate baicalin in rats.

    PubMed

    Wu, Tao; Li, Xi-Ping; Xu, Yan-Jiao; Du, Guang; Liu, Dong

    2013-11-01

    Baicalin is a major bioactive component of Scutellaria baicalensis and a substrate of multiple drug resistance-associated protein 2. Expression of multiple drug resistance-associated protein 2 is regulated by NF-E2-related factor 2. The aim of this study was to explore whether ursodeoxycholic acid, an NF-E2-related factor 2 activator, could influence the oral bioavailability of baicalin. A single dose of baicalin (200 mg/kg) was given orally to rats pretreated with ursodeoxycholic acid (75 mg/kg and 150 mg/kg, per day, intragastrically) or normal saline (per day, intragastrically) for six consecutive days. The plasma concentration of baicalin was measured with the HPLC method. The result indicated that the oral bioavailability of baicalin was significantly and dose-dependently reduced in rats pretreated with ursodeoxycholic acid. Compared with control rats, the mean area under concentration-time curve of baicalin was reduced from 13.25 ± 0.24 mg/L h to 7.62 ± 0.15 mg/L h and 4.97 ± 0.21 mg/L h, and the C(max) value was decreased from 1.31 ± 0.03 mg/L to 0.62 ± 0.05 mg/L and 0.36 ± 0.04 mg/L in rats pretreated with ursodeoxycholic acid at doses of 75 mg/kg and 150 mg/kg, respectively, for six consecutive days. Hence, ursodeoxycholic acid treatment reduced the oral bioavailability of baicalin in rats, probably due to the enhanced efflux of baicalin from the intestine and liver by multiple drug resistance-associated protein 2. PMID:24135887

  19. Structural Transformation of Isolated Poplar and Switchgrass Lignins from Dilute Acid Pretreatment

    SciTech Connect

    Sun, Qining; Pu, Yunqiao; Meng, Xianzhi; Wells, Tyrone; Ragauskas, Arthur J.

    2015-08-27

    A key step in conversion of cellulosic biomass into sustainable fuels and chemicals is thermochemical pretreatment to reduce plant cell wall recalcitrance. Obtaining an improved understanding of the fundamental chemistry of lignin, the most recalcitrant component of biomass, during pretreatment is critical to the continued development of renewable biofuel production. To examine the intrinsic chemistry of lignin during dilute acid pretreatment (DAP), lignin was isolated from poplar and switchgrass using a cellulolytic enzyme system and then treated under DAP conditions. These results highlight that lignin is subjected to depolymerization reactions within the first 2 min of dilute acid pretreatment and these changes are accompanied by increased generation of aliphatic and phenolic hydroxyl groups of lignin. This is followed by a competing set of depolymerization and repolymerization reactions that lead to a decrease in the content of guaiacyl lignin units and an increase in condensed lignin units as the reaction residence time is extended beyond 5 min. Finally, we showed that a detailed comparison of changes in functional groups and molecular weights of cellulolytic enzyme lignins with different structural parameters, related to the recalcitrant properties of lignin, could be successfully altered during DAP conditions.

  20. Degradation of carbohydrates during dilute sulfuric acid pretreatment can interfere with lignin measurements in solid residues.

    PubMed

    Katahira, Rui; Sluiter, Justin B; Schell, Daniel J; Davis, Mark F

    2013-04-01

    The lignin content measured after dilute sulfuric acid pretreatment of corn stover indicates more lignin than could be accounted for on the basis of the untreated corn stover lignin content. This phenomenon was investigated using a combination of (13)C cross-polarization/magic-angle spinning (CP/MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy and lignin removal using acid chlorite bleaching. Only minimal contamination with carbohydrates and proteins was observed in the pretreated corn stover. Incorporating degradation products from sugars was also investigated using (13)C-labeled sugars. The results indicate that sugar degradation products are present in the pretreatment residue and may be intimately associated with the lignin. Studies comparing whole corn stover (CS) to extractives-free corn stover [CS(Ext)] clearly demonstrated that extractives are a key contributor to the high-lignin mass balance closure (MBC). Sugars and other low molecular weight compounds present in plant extractives polymerize and form solids during pretreatment, resulting in apparent Klason lignin measurements that are biased high. PMID:23428141

  1. Structural Transformation of Isolated Poplar and Switchgrass Lignins from Dilute Acid Pretreatment

    DOE PAGESBeta

    Sun, Qining; Pu, Yunqiao; Meng, Xianzhi; Wells, Tyrone; Ragauskas, Arthur J.

    2015-08-27

    A key step in conversion of cellulosic biomass into sustainable fuels and chemicals is thermochemical pretreatment to reduce plant cell wall recalcitrance. Obtaining an improved understanding of the fundamental chemistry of lignin, the most recalcitrant component of biomass, during pretreatment is critical to the continued development of renewable biofuel production. To examine the intrinsic chemistry of lignin during dilute acid pretreatment (DAP), lignin was isolated from poplar and switchgrass using a cellulolytic enzyme system and then treated under DAP conditions. These results highlight that lignin is subjected to depolymerization reactions within the first 2 min of dilute acid pretreatment andmore » these changes are accompanied by increased generation of aliphatic and phenolic hydroxyl groups of lignin. This is followed by a competing set of depolymerization and repolymerization reactions that lead to a decrease in the content of guaiacyl lignin units and an increase in condensed lignin units as the reaction residence time is extended beyond 5 min. Finally, we showed that a detailed comparison of changes in functional groups and molecular weights of cellulolytic enzyme lignins with different structural parameters, related to the recalcitrant properties of lignin, could be successfully altered during DAP conditions.« less

  2. Dilute-sulfuric acid pretreatment of corn stover in pilot-scale reactor: investigation of yields, kinetics, and enzymatic digestibilities of solids.

    PubMed

    Schell, Daniel J; Farmer, Jody; Newman, Millie; McMillan, James D

    2003-01-01

    Corn stover is a domestic feedstock that has potential to produce significant quantities of fuel ethanol and other bioenergy and biobased products. However, comprehensive yield and carbon mass balance information and validated kinetic models for dilute-sulfuric acid (H2SO4) pretreatment of corn stover have not been available. This has hindered the estimation of process economics and also limited the ability to perform technoeconomic modeling to guide research. To better characterize pretreatment and assess its kinetics, we pretreated corn stover in a continuous 1 t/d reactor. Corn stover was pretreated at 20% (w/w) solids concentration over a range of conditions encompassing residence times of 3-12 min, temperatures of 165- 195 degrees C, and H2SO4 concentrations of 0.5-1.4% (w/w). Xylan conversion yield and carbon mass balance data were collected at each run condition. Performance results were used to estimate kinetic model parameters assuming biphasic hemicellulose hydrolysis and a hydrolysis mechanism incorporating formation of intermediate xylo-oligomers. In addition, some of the pretreated solids were tested in a simultaneous saccharification and fermentation (SSF) process to measure the reactivity of their cellulose component to enzymatic digestion by cellulase enzymes. Monomeric xylose yields of 69-71% and total xylose yields (monomers and oligomers) of 70-77% were achieved with performance level depending on pretreatment severity. Cellulose conversion yields in SSF of 80-87% were obtained for some of the most digestible pretreated solids. PMID:12721476

  3. Optimizing dilute-acid pretreatment of rapeseed straw for extraction of hemicellulose.

    PubMed

    Jeong, Tae-Su; Um, Byung-Hwan; Kim, Jun-Seok; Oh, Kyeong-Keun

    2010-05-01

    Biological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars prior to fermentation. Hydrolysis can be performed enzymatically or with mineral acids. In this study, dilute sulfuric acid was used as a catalyst for the pretreatment of rapeseed straw. The purpose of this study is to optimize the pretreatment process in a 15-mL bomb tube reactor and investigate the effects of the acid concentration, temperature, and reaction time. These parameters influence hemicellulose removal and production of sugars (xylose, glucose, and arabinose) in the hydrolyzate as well as the formation of by-products (furfural, 5-hydroxymethylfurfural, and acetic acid). Statistical analysis was based on a model composition corresponding to a 3(3) orthogonal factorial design and employed the response surface methodology to optimize the pretreatment conditions, aiming to attain maximum xylan, mannan, and galactan (XMG) extraction from hemicellulose of rapeseed straw. The obtained optimum conditions were: H2SO4 concentration of 1.76% and temperature of 152.6 degrees C with a reaction time of 21 min. Under these optimal conditions, 85.5% of the total sugar was recovered after acid hydrolysis (78.9% XMG and 6.6% glucan). The hydrolyzate contained 1.60 g/L glucose, 0.61 g/L arabinose, 10.49 g/L xylose, mannose, and galactose, 0.39 g/L cellobiose, 0.94 g/L fructose, 0.02 g/L 1,6-anhydro-glucose, 1.17 g/L formic acid, 2.94 g/L acetic acid, 0.04 g/L levulinic acid, 0.04 g/L 5-hydroxymethylfurfural, and 0.98 g/L furfural. PMID:20087686

  4. Effect of oxalic acid pre-treatment in restorations of non-carious cervical lesions: A randomized clinical trial

    PubMed Central

    de Souza, André Mattos Brito; Colares, Regina Claudia Ramos; Mendonça, Juliano Satori; Rodrigues, Lidiany Karla Azevedo; Santiago, Sérgio Lima

    2014-01-01

    Context: Non-carious cervical lesions are usually associated with dentin hypersensitivity. The use of oxalic acid in restorations of these lesions could be beneficial in relieving pain. Aims: To evaluate the use of oxalic acid in restorations of non-carious cervical lesions. Settings and Design: A randomized clinical trial. Subjects and Methods: One operator placed 90 restorations in 20 volunteers of both sexes, with at least two lesions to be restored with the techniques: Control — Restoration with total-etch technique and Experimental — Restoration with pretreatment with oxalic acid followed by application of adhesive system. The restorative adhesive system used was XP Bond/Durafill. The restorations were directly assessed by two independent examiners using a modified United States Public Health Service (USPHS) method at baseline, 6 and 12 months, taking into account the following criteria: Retention (R), marginal integrity (MI), marginal discoloration (MD), postoperative sensitivity (S), caries (C), and anatomic form (AF). Statistical analysis used: The data were statistically analyzed using the Fisher exact and McNemar tests. The level of significance was set at 5%. Results: After 1 year, the results of restorations clinically satisfactory obtained for the control and experimental group respectively were: R (97% / 89%), MI (100% / 100%), MD (100% / 100%), S (100% / 100%), C (100% / 100%), and AF (100% / 100%). Conclusions: The use of oxalic acid as an agent of dentin pretreatment did not influence the clinical performance of restorations in non-carious cervical lesions after 1 year. PMID:25298641

  5. Pilot-scale On-farm Pretreatment of Perennial Grasses with Dilute Acid and Alkali for Fuel Ethanol Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were pretreated with sulfuric acid or calcium hydroxide 50 g/kg DM at both the laboratory (250 g DM) and pilot-scale (250 kg DM) and anaerobically stored for two durations, 60 and 180 days. Pretreated and untreated samp...

  6. Kinetic study of enzymatic hydrolysis of acid-pretreated coconut coir

    NASA Astrophysics Data System (ADS)

    Fatmawati, Akbarningrum; Agustriyanto, Rudy

    2015-12-01

    Biomass waste utilization for biofuel production such as bioethanol, has become more prominent currently. Coconut coir is one of lignocellulosic food wastes, which is abundant in Indonesia. Bioethanol production from such materials consists of more than one step. Pretreatment and enzymatic hydrolysis is crucial steps to produce sugar which can then be fermented into bioethanol. In this research, ground coconut coir was pretreated using dilute sulfuric acid at 121°C. This pretreatment had increased the cellulose content and decreased the lignin content of coconut coir. The pretreated coconut coir was hydrolyzed using a mix of two commercial cellulase enzymes at pH of 4.8 and temperature of 50°C. The enzymatic hydrolysis was conducted at several initial coconut coir slurry concentrations (0.1-2 g/100 mL) and reaction times (2-72 hours). The reducing sugar concentration profiles had been produced and can be used to obtain reaction rates. The highest reducing sugar concentration obtained was 1,152.567 mg/L, which was produced at initial slurry concentration of 2 g/100 mL and 72 hours reaction time. In this paper, the reducing sugar concentrations were empirically modeled as a function of reaction time using power equations. Michaelis-Menten kinetic model for enzymatic hydrolysis reaction is adopted. The kinetic parameters of that model for sulfuric acid-pretreated coconut coir enzymatic hydrolysis had been obtained which are Vm of 3.587×104 mg/L.h, and KM of 130.6 mg/L.

  7. Ammonia recycled percolation as a complementary pretreatment to the dilute-acid process

    SciTech Connect

    Wu, Zhangwen, Lee, Y.Y.

    1997-12-31

    A two-stage dilute-acid percolation (DA) was investigated as a pre-treatment method for switchgrass. With use of extremely low acid (0.078 wt% sulfuric acid) under moderate temperature (145-170{degrees}C), hemicellulose in switchgrass was completely solubilized showing no sugar decomposition. The treated switchgrass contained about 70% glucan and 30% lignin. The high lignin content in the treated feedstock raises a concern that it may cause a high enzyme consumption because of irreversible adsorption of cellulose enzymes to lignin. This problem may be amplified in the SSF operation since it is usually run in fed-batch mode and the residual lignin is accumulated. The DA pretreatment was, therefore, combined with the ammonia recycled percolation (ARP) process that has been proven to be effective in delignification. The combined pretreatment essentially fractionated the switchgrass into three major components. The treated feedstock contained about 90% glucan and 10% lignin. The digestibility of these samples was consistently higher than that of DA treated samples. Further study on the interaction of cellulase with xylan and that with lignin has shown that the enzymatic hydrolysis of cellulose is inhibited by lignin as well as xylan. The external xylan was found to be a noncompetitive inhibitor to cellulose hydrolysis. The cellulose used in this study was proven to have the xylanase activity. 23 refs., 8 figs., 4 tabs.

  8. 1,2-Dichlorobenzene Pretreatment via Phosphoric Acid-Mediated Fenton Reagent.

    PubMed

    Richmond, Mark D

    2015-07-01

    A large industrial water resource recovery facility needed to significantly reduce the amount of 1,2-dichlorobenzene (ODCB) entering its biological treatment units. Numerous Advanced Oxidation Processes (AOPs) were considered based on literature and industry reports. Many AOPs appear to be incompatible with some of the native species present in groundwater or wastewater matrices. Iron, in particular, is often viewed as a nuisance increasing the complexity of the overall treatment scheme. The approach used in the current study was to incorporate the new AOP into the existing groundwater matrix and facilities as much as possible. To that end, native iron was exploited as the reaction catalyst, an acid was selected to fit with current macro nutrient needs of the biotreatment units, and the reactor was designed to require minimum modification of the existing facilities. The "green chemical" (Noyori, 2003) treatment process selected was demonstrated at full-scale, achieving good agreement with the results of prior laboratory studies. Up to eighty percent destruction of ODCB was demonstrated in a new pretreatment unit whose effluent fit seamlessly with the existing bioreactors. PMID:26163501

  9. Solid acid catalysts pretreatment and enzymatic hydrolysis of macroalgae cellulosic residue for the production of bioethanol.

    PubMed

    Tan, Inn Shi; Lee, Keat Teong

    2015-06-25

    The aim of this study is to investigate the technical feasibility of converting macroalgae cellulosic residue (MCR) into bioethanol. An attempt was made to present a novel, environmental friendly and economical pretreatment process that enhances enzymatic conversion of MCR to sugars using Dowex (TM) Dr-G8 as catalyst. The optimum yield of glucose reached 99.8% under the optimal condition for solid acid pretreatment (10%, w/v biomass loading, 4%, w/v catalyst loading, 30min, 120°C) followed by enzymatic hydrolysis (45FPU/g of cellulase, 52CBU/g of β-glucosidase, 50°C, pH 4.8, 30h). The yield of sugar obtained was found more superior than conventional pretreatment process using H2SO4 and NaOH. Biomass loading for the subsequent simultaneous saccharification and fermentation (SSF) of the pretreated MCR was then optimized, giving an optimum bioethanol yield of 81.5%. The catalyst was separated and reused for six times, with only a slight drop in glucose yield. PMID:25839825

  10. Structural features of dilute acid, steam exploded, and alkali pretreated mustard stalk and their impact on enzymatic hydrolysis.

    PubMed

    Kapoor, Manali; Raj, Tirath; Vijayaraj, M; Chopra, Anju; Gupta, Ravi P; Tuli, Deepak K; Kumar, Ravindra

    2015-06-25

    To overcome the recalcitrant nature of biomass several pretreatment methodologies have been explored to make it amenable to enzymatic hydrolysis. These methodologies alter cell wall structure primarily by removing/altering hemicelluloses and lignin. In this work, alkali, dilute acid, steam explosion pretreatment are systematically studied for mustard stalk. To assess the structural variability after pretreatment, chemical analysis, surface area, crystallinity index, accessibility of cellulose, FT-IR and thermal analysis are conducted. Although the extent of enzymatic hydrolysis varies upon the methodologies used, nevertheless, cellulose conversion increases from <10% to 81% after pretreatment. Glucose yield at 2 and 72h are well correlated with surface area and maximum adsorption capacity. However, no such relationship is observed for xylose yield. Mass balance of the process is also studied. Dilute acid pretreatment is the best methodology in terms of maximum sugar yield at lower enzyme loading. PMID:25839820

  11. Incidence and clinical significance of ESR1 mutations in heavily pretreated metastatic breast cancer patients

    PubMed Central

    Niu, Jiaxin; Andres, Grant; Kramer, Kim; Kundranda, Madappa N; Alvarez, Ricardo H; Klimant, Eiko; Parikh, Ankur R; Tan, Bradford; Staren, Edgar D; Markman, Maurie

    2015-01-01

    Background ESR1 mutation has recently emerged as one of the important mechanisms involved in endocrine resistance. The incidence and clinical implication of ESR1 mutation has not been well evaluated in heavily pretreated breast cancer patients. Methods We conducted a retrospective review of advanced breast cancer patients with tumors who underwent next-generation sequencing genomic profiling using Foundation One test at Cancer Treatment Centers of America® regional hospitals between November 2012 and November 2014. Results We identified a total of 341 patients including 217 (59%) estrogen receptor (ER)+, 177 (48%) progesterone receptor (PR)+, 30 (8%) hormone receptor+/HER2 positive, and 119 (32%) triple negative patients. ESR1 mutation was noted in 27/222 (12.1%) ER+ or PR+ breast cancer patients. All ER+ patients received at least one line of an aromatase inhibitor. All 28 patients were found to harbor ESR1 mutations affecting ligand-binding domain with the most common mutations affecting Y537 (17/28, 60.7%) and D538 (9/28, 32.1%). In this cohort, 19 (67.9%) patients carried three or more, seven (25%) patients had one or two additional genomic alterations and one (3.6%) patient had an ESR1 mutation only. Of 28 patients, three patients were treated with fulvestrant immediately before and two patients were treated after next-generation sequencing testing; only one patient achieved stable disease for 8 months and the other four patients had progression of disease. In all, 3/3 (100%) patients before testing and 2/4 (50%) after testing treated with exemestane and everolimus achieved stable disease for at least 6 months. Conclusion ESR1 mutation was found in 12.1% of a large cohort of advanced breast cancer patients. Exemestane in combination with everolimus might be a reasonable option. Prospective studies are warranted to validate these findings. PMID:26648736

  12. Pretreatment of rice straw with combined process using dilute sulfuric acid and aqueous ammonia

    PubMed Central

    2013-01-01

    Background Use of lignocellulosic biomass has received attention lately because it can be converted into various versatile chemical compounds by biological processes. In this study, a two-step pretreatment with dilute sulfuric acid and aqueous ammonia was performed efficiently on rice straw to obtain fermentable sugar. The soaking in aqueous ammonia process was also optimized by a statistical method. Results Response surface methodology was employed. The determination coefficient (R2) value was found to be 0.9607 and the coefficient of variance was 6.77. The optimal pretreatment conditions were a temperature of 42.75°C, an aqueous ammonia concentration of 20.93%, and a reaction time of 48 h. The optimal enzyme concentration for saccharification was 30 filter paper units. The crystallinity index was approximately 60.23% and the Fourier transform infrared results showed the distinct peaks of glucan. Ethanol production using Saccharomyces cerevisiae K35 was performed to verify whether the glucose saccharified from rice straw was fermentable. Conclusions The combined pretreatment using dilute sulfuric acid and aqueous ammonia on rice straw efficiently yielded fermentable sugar and achieved almost the same crystallinity index as that of α-cellulose. PMID:23898802

  13. Redistribution of Xylan in Maize Cell Walls During Dilute Acid Pretreatment

    SciTech Connect

    Brunecky, R.; Vinzant, T. B.; Porter, S. E.; Donohoe, B. S.; Johnson, D. K.; Himmel, M. E.

    2009-04-15

    Developing processes for the conversion of biomass for use in transportation fuels production is becoming a critically important economic and engineering challenge. Dilute acid pretreatment is a promising technology for increasing the enzymatic digestibility of lignocellulosic biomass. However, a deeper understanding of the pretreatability of biomass is needed so that the rate of formation and yields of sugars can be increased. Xylan is an important hemicellulosic component of the plant cell wall and acts as a barrier to cellulose, essentially blocking cellulase action. To better understand xylan hydrolysis in corn stover, we have studied changes in the distribution of xylan caused by dilute acid pretreatment using correlative microscopy. A dramatic loss of xylan antibody signal from the center of the cell wall and an increase or retention of xylan at the plasma membrane interface and middle lamella of the cell were observed by confocal laser scanning microscopy (CLSM). We also observed a reduction in xylan fluorescence signal by CLSM that is generally consistent with the decrease in xylan content measured experimentally in the bulk sample, however, the compartmentalization of this xylan retention was not anticipated.

  14. Effect of acid pretreatment on different parts of corn stalk for second generation ethanol production.

    PubMed

    Li, Ping; Cai, Di; Luo, Zhangfeng; Qin, Peiyong; Chen, Changjing; Wang, Yong; Zhang, Changwei; Wang, Zheng; Tan, Tianwei

    2016-04-01

    In this study, the effects of different parts of corn stalk, including stem, leaf, flower, cob and husk on second generation ethanol production were evaluated. FTIR, XRD and SEM were performed to investigate the effect of dilute acid pretreatment. The bagasse obtained after pretreatment were further hydrolyzed by cellulase and used as the substrate for ethanol fermentation. As results, hemicelluloses fractions in different parts of corn stalk were dramatically removed and the solid fractions showed vivid compositions and crystallinities. Compared with other parts of corn stalk, the cob had higher sugar content and better enzymatic digestibility. The highest glucose yield of 94.2% and ethanol production of 24.0gL(-1) were achieved when the cob was used as feedstock, while the glucose yield and the ethanol production were only 86.0% and 17.1gL(-1) in the case of flower. PMID:26849200

  15. Thermal and thermo-chemical pre-treatment of four waste residues and the effect on acetic acid production and methane synthesis.

    PubMed

    Strong, P J; Gapes, D J

    2012-09-01

    In this study four diverse solid waste substrates (coal, Kraft pulp solids, chicken feathers and chicken processing waste) were thermally pre-treated (70, 140 and 200 °C), under an inert (nitrogen) or oxidative (oxygen) atmosphere, and then anaerobically digested. Membrane inlet mass spectrometry during the thermal and thermo-chemical reactions was successfully used to establish oxygen and carbon dioxide gas fluxes and product formation (acetic acid). There was significant solids hydrolysis pre-treatment at 200 °C under an oxidative atmosphere, as indicated by a decrease in the volatile suspended solids and an increase in dissolved organic carbon. Greater concentrations of volatile fatty acids were produced under oxidative conditions at higher temperatures. The methane yield more than tripled for feathers after pre-treatment at 140 °C (under both atmospheres), but decreased after oxidative pre-treatment at 200 °C, due to the destruction of available carbon by the thermo-chemical reaction. Methane yield more than doubled for the Kraft pulp solids with the 200 °C pre-treatment under oxidative conditions. This study illustrated the power of wet oxidation for solids destruction and its potential to improve methane yields generated during anaerobic digestion. PMID:22609530

  16. Integrated chemical and multi-scale structural analyses for the processes of acid pretreatment and enzymatic hydrolysis of corn stover.

    PubMed

    Chen, Longjian; Li, Junbao; Lu, Minsheng; Guo, Xiaomiao; Zhang, Haiyan; Han, Lujia

    2016-05-01

    Corn stover was pretreated with acid under moderate conditions (1.5%, w/w, 121°C, 60min), and kinetic enzymolysis experiments were performed on the pretreated substrate using a mixture of Celluclast 1.5L (20FPU/g dry substrate) and Novozyme 188 (40CBU/g dry substrate). Integrated chemical and multi-scale structural methods were then used to characterize both processes. Chemical analysis showed that acid pretreatment removed considerable hemicellulose (from 19.7% in native substrate to 9.28% in acid-pretreated substrate) and achieved a reasonably high conversion efficiency (58.63% of glucose yield) in the subsequent enzymatic hydrolysis. Multi-scale structural analysis indicated that acid pretreatment caused structural changes via cleaving acetyl linkages, solubilizing hemicellulose, relocating cell wall surfaces and enlarging substrate porosity (pore volume increased from 0.0067cm(3)/g in native substrate to 0.019cm(3)/g in acid-pretreated substrate), thereby improving the polysaccharide digestibility. PMID:26876990

  17. Effect of mechanical disruption on the effectiveness of three reactors used for dilute acid pretreatment of corn stover Part 1: chemical and physical substrate analysis

    PubMed Central

    2014-01-01

    Background There is considerable interest in the conversion of lignocellulosic biomass to liquid fuels to provide substitutes for fossil fuels. Pretreatments, conducted to reduce biomass recalcitrance, usually remove at least some of the hemicellulose and/or lignin in cell walls. The hypothesis that led to this research was that reactor type could have a profound effect on the properties of pretreated materials and impact subsequent cellulose hydrolysis. Results Corn stover was dilute-acid pretreated using commercially relevant reactor types (ZipperClave® (ZC), Steam Gun (SG) and Horizontal Screw (HS)) under the same nominal conditions. Samples produced in the SG and HS achieved much higher cellulose digestibilities (88% and 95%, respectively), compared to the ZC sample (68%). Characterization, by chemical, physical, spectroscopic and electron microscopy methods, was used to gain an understanding of the effects causing the digestibility differences. Chemical differences were small; however, particle size differences appeared significant. Sum-frequency generation vibrational spectra indicated larger inter-fibrillar spacing or randomization of cellulose microfibrils in the HS sample. Simons’ staining indicated increased cellulose accessibility for the SG and HS samples. Electron microscopy showed that the SG and HS samples were more porous and fibrillated because of mechanical grinding and explosive depressurization occurring with these two reactors. These structural changes most likely permitted increased cellulose accessibility to enzymes, enhancing saccharification. Conclusions Dilute-acid pretreatment of corn stover using three different reactors under the same nominal conditions gave samples with very different digestibilities, although chemical differences in the pretreated substrates were small. The results of the physical and chemical analyses of the samples indicate that the explosive depressurization and mechanical grinding with these reactors increased

  18. Enhancing post aerobic digestion of full-scale anaerobically digested sludge using free nitrous acid pretreatment.

    PubMed

    Wang, Qilin; Zhou, Xu; Peng, Lai; Wang, Dongbo; Xie, Guo-Jun; Yuan, Zhiguo

    2016-05-01

    Post aerobic digestion of anaerobically digested sludge (ADS) has been extensively applied to the wastewater treatment plants to enhance sludge reduction. However, the degradation of ADS in the post aerobic digester itself is still limited. In this work, an innovative free nitrous acid (HNO2 or FNA)-based pretreatment approach is proposed to improve full-scale ADS degradation in post aerobic digester. The post aerobic digestion was conducted by using an activated sludge to aerobically digest ADS for 4 days. Degradations of the FNA-treated (treated at 1.0 and 2.0 mg N/L for 24 h) and untreated ADSs were then determined and compared. The ADS was degraded by 26% and 32%, respectively, in the 4-day post aerobic digestion period while being pretreated at 1.0 and 2.0 mg HNO2-N/L. In comparison, only 20% of the untreated ADS was degraded. Economic analysis demonstrated that the implementation of FNA pretreatment can be economically favourable or not depending on the sludge transport and disposal cost. PMID:26901471

  19. Fermentation of dilute acid pretreated Populus by Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis

    DOE PAGESBeta

    Yee, Kelsey L.; Rodriguez, Jr., Miguel; Hamilton, Choo Yieng; Hamilton-Brehm, Scott D.; Thompson, Olivia A.; Elkins, James G.; Davison, Brian H.; Mielenz, Jonathan R.

    2015-07-25

    Consolidated bioprocessing (CBP), which merges enzyme production, biomass hydrolysis, and fermentation into a single step, has the potential to become an efficient and economic strategy for the bioconversion of lignocellulosic feedstocks to transportation fuels or chemicals. In this study, we evaluated Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis, three , thermophilic,cellulolytic, mixed-acid fermenting candidate CBP microorganisms, for their fermentation capabilities using dilute acid pretreated Populus as a model biomass feedstock. Under pH controlled, anaerobic fermentation conditions, each candidate successfully digested a minimum of 75% of the cellulose from dilute acid pretreated Populus, as indicated by an increase in planktonic cellsmore » and end-product metabolites and a concurrent decrease in glucan content. C. thermocellum, which employs a cellulosomal approach to biomass degradation, required 120 hours to achieve 75% cellulose utilization. In contrast, the non-cellulosomal, secreted hydrolytic enzyme system of the Caldicellulosiruptor sp. required 300 hours to achieve similar results. End-point fermentation conversions for C. thermocellum, C. bescii, and C. obsidiansis were determined to be 0.29, 0.34, and 0.38 grams of total metabolites per gram of loaded glucan, respectively. This data provide a starting point for future strain engineering efforts that can serve to improve the biomass fermentation capabilities of these three promising candidate CBP platforms.« less

  20. Pretreatment with xylanase and its significance in hemicellulose removal from mixed hardwood kraft pulp as a process step for viscose.

    PubMed

    Kaur, Prabhjot; Bhardwaj, Nishi K; Sharma, Jitender

    2016-07-10

    The upturn of viscose fiber market has triggered an augmented dissolving pulp usage over the last decade. Dissolving pulp is feasible to obtain from kraft pulp after two essential steps including hemicellulose removal and subsequent pulp activation. Prerequisite of conversion being hemicellulose reduction can be gently done by using xylanase treatment prior to alkali extraction. Herein, the significance of xylanase treatment and the optimum xylanase dose required in conjunction with subsequent alkali extraction was investigated. An increase in xylanase dose prior to alkali extraction had no significant effect on pentosans while the Fock reactivity and viscosity both improved at the dose of 50AXU/g. Also, alkali extraction without xylanase pretreatment resulted in decreased Fock reactivity, alpha cellulose, brightness and viscosity of paper grade pulp. A moderate dose of xylanase prior to alkali extraction can thus be used to facilitate the hemicellulose removal while simultaneously protecting the native structure of cellulose. PMID:27106156

  1. Response surface optimization of corn stover pretreatment using dilute phosphoric acid for enzymatic hydrolysis and ethanol production.

    PubMed

    Avci, Ayse; Saha, Badal C; Dien, Bruce S; Kennedy, Gregory J; Cotta, Michael A

    2013-02-01

    Dilute H(3)PO(4) (0.0-2.0%, v/v) was used to pretreat corn stover (10%, w/w) for conversion to ethanol. Pretreatment conditions were optimized for temperature, acid loading, and time using central composite design. Optimal pretreatment conditions were chosen to promote sugar yields following enzymatic digestion while minimizing formation of furans, which are potent inhibitors of fermentation. The maximum glucose yield (85%) was obtained after enzymatic hydrolysis of corn stover pretreated with 0.5% (v/v) acid at 180°C for 15min while highest yield for xylose (91.4%) was observed from corn stover pretreated with 1% (v/v) acid at 160°C for 10min. About 26.4±0.1g ethanol was produced per L by recombinant Escherichia coli strain FBR5 from 55.1±1.0g sugars generated from enzymatically hydrolyzed corn stover (10%, w/w) pretreated under a balanced optimized condition (161.81°C, 0.78% acid, 9.78min) where only 0.4±0.0g furfural and 0.1±0.0 hydroxylmethyl furfural were produced. PMID:23334017

  2. Pretreating wheat straw by the concentrated phosphoric acid plus hydrogen peroxide (PHP): Investigations on pretreatment conditions and structure changes.

    PubMed

    Wang, Qing; Hu, Jinguang; Shen, Fei; Mei, Zili; Yang, Gang; Zhang, Yanzong; Hu, Yaodong; Zhang, Jing; Deng, Shihuai

    2016-01-01

    Wheat straw was pretreated by PHP (the concentrated H3PO4 plus H2O2) to clarify effects of temperature, time and H3PO4 proportion on hemicellulose removal, delignification, cellulose recovery and enzymatic digestibility. Overall, hemicellulose removal was intensified by PHP comparing to the concentrated H3PO4. Moreover, efficient delignification specially happened in PHP pretreatment. Hemicellulose removal and delignification by PHP positively responded to temperature and time. Increasing H3PO4 proportion in PHP can promote hemicellulose removal, however, decrease the delignification. Maximum hemicellulose removal and delignification were achieved at 100% and 83.7% by PHP. Enzymatic digestibility of PHP-pretreated wheat straw was greatly improved by increasing temperature, time and H3PO4 proportion, and complete hydrolysis can be achieved consequently. As temperature of 30-40°C, time of 2.0 h and H3PO4 proportion of 60% were employed, more than 92% cellulose was retained in the pretreated wheat straw, and 29.1-32.6g glucose can be harvested from 100g wheat straw. PMID:26264398

  3. Butyric acid fermentation from pretreated and hydrolysed wheat straw by an adapted Clostridium tyrobutyricum strain

    PubMed Central

    Baroi, G N; Baumann, I; Westermann, P; Gavala, H N

    2015-01-01

    Butyric acid is a valuable building-block for the production of chemicals and materials and nowadays it is produced exclusively from petroleum. The aim of this study was to develop a suitable and robust strain of Clostridium tyrobutyricum that produces butyric acid at a high yield and selectivity from lignocellulosic biomasses. Pretreated (by wet explosion) and enzymatically hydrolysed wheat straw (PHWS), rich in C6 and C5 sugars (71.6 and 55.4 g l−1 of glucose and xylose respectively), was used as substrate. After one year of serial selections, an adapted strain of C. tyrobutyricum was developed. The adapted strain was able to grow in 80% (v v−1) PHWS without addition of yeast extract compared with an initial tolerance to less than 10% PHWS and was able to ferment both glucose and xylose. It is noticeable that the adapted C. tyrobutyricum strain was characterized by a high yield and selectivity to butyric acid. Specifically, the butyric acid yield at 60–80% PHWS lie between 0.37 and 0.46 g g−1 of sugar, while the selectivity for butyric acid was as high as 0.9–1.0 g g−1 of acid. Moreover, the strain exhibited a robust response in regards to growth and product profile at pH 6 and 7. PMID:26230610

  4. Optimization of Sulfide/Sulfite Pretreatment of Lignocellulosic Biomass for Lactic Acid Production

    PubMed Central

    Adnan, Ahmad; Qureshi, Fahim Ashraf

    2013-01-01

    Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na2S and Na2SO3, which had high coefficient of determination (R2) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na2S and Na2SO3 remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na2S at 130°C for 2.3–3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na2SO3 showed higher hydrolysis yield (86.34%) as compared to Na2S while other biomass substrates showed 2.0–3.0% less yield with Na2SO3. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL−1 of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively. PMID:24058918

  5. Optimization of sulfide/sulfite pretreatment of lignocellulosic biomass for lactic acid production.

    PubMed

    Idrees, Muhammad; Adnan, Ahmad; Qureshi, Fahim Ashraf

    2013-01-01

    Potential of sodium sulfide and sodium sulfite, in the presence of sodium hydroxide was investigated to pretreat the corncob (CC), bagasse (BG), water hyacinth and rice husk (RH) for maximum digestibility. Response Surface Methodology was employed for the optimization of pretreatment factors such as temperature, time and concentration of Na₂S and Na₂SO₃, which had high coefficient of determination (R²) along with low probability value (P), indicating the reliable predictability of the model. At optimized conditions, Na₂S and Na₂SO₃ remove up to 97% lignin, from WH and RH, along with removal of hemicellulose (up to 93%) during pretreatment providing maximum cellulose, while in BG and CC; 75.0% and 90.0% reduction in lignin and hemicellulose was observed. Saccharification efficiency of RH, WH, BG and CC after treatment with 1.0% Na₂S at 130°C for 2.3-3.0 h was 79.40, 85.93, 87.70, and 88.43%, respectively. WH treated with Na₂SO₃ showed higher hydrolysis yield (86.34%) as compared to Na₂S while other biomass substrates showed 2.0-3.0% less yield with Na₂SO₃. Resulting sugars were evaluated as substrate for lactic acid production, yielding 26.48, 25.36, 31.73, and 30.31 gL⁻¹ of lactic acid with 76.0, 76.0, 86.0, and 83.0% conversion yield from CC, BG, WH, and RH hydrolyzate, respectively. PMID:24058918

  6. Effect of ultrasonic pre-treatment on low temperature acid hydrolysis of oil palm empty fruit bunch.

    PubMed

    Yunus, Robiah; Salleh, Shanti Faridah; Abdullah, Nurhafizah; Biak, Dyg Radiah Awg

    2010-12-01

    Various pre-treatment techniques change the physical and chemical structure of the lignocellulosic biomass and improve hydrolysis rates. The effect of ultrasonic pre-treatment on oil palm empty fruit bunch (OPEFB) fibre prior to acid hydrolysis has been evaluated. The main objective of this study was to determine if ultrasonic pre-treatment could function as a pre-treatment method for the acid hydrolysis of OPEFB fibre at a low temperature and pressure. Hydrolysis at a low temperature was studied using 2% sulphuric acid; 1:25 solid liquid ratio and 100 degrees C operating temperature. A maximum xylose yield of 58% was achieved when the OPEFB fibre was ultrasonicated at 90% amplitude for 45min. In the absence of ultrasonic pre-treatment only 22% of xylose was obtained. However, no substantial increase of xylose formation was observed for acid hydrolysis at higher temperatures of 120 and 140 degrees C on ultrasonicated OPEFB fibre. The samples were then analysed using a scanning electron microscope (SEM) to describe the morphological changes of the OPEFB fibre. The SEM observations show interesting morphological changes within the OPEFB fibre for different acid hydrolysis conditions. PMID:20719502

  7. Acid and enzymatic hydrolysis of pretreated cellulosic materials as an analytical tool

    SciTech Connect

    Ladisch, C.M.; Chiasson, C.M.; Tsao, G.T.

    1982-07-01

    A rapid and accurate procedure for the quantitative analysis of cellulose in textiles based on acid and enzymatic hydrolysis was investigated. Total hydrolysis was achieved by a two-step procedure: the cellulose in the sample was first dissolved in cadoxen and then reprecipitated. The material, thus pretreated, was then hydrolyzed with acid or enzyme catalytic agents. Hydrolysis products were detected and quantified by colorimetric, enzymic, and liquid chromatographic methods of analysis. Samples examined included cotton, rayon, Avicel, CF-11, and cotton/polyester blends. The specificity of the enzyme hydrolysis method allowed analysis of raw cotton without prior purification. Results of the analyses were compared to those obtained by existing methods of analysis.

  8. Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

    NASA Technical Reports Server (NTRS)

    Muirhead, Dean; Carrier, Christopher

    2012-01-01

    In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines

  9. Validation Testing of the Nitric Acid Dissolution Step Within the K Basin Sludge Pretreatment Process

    SciTech Connect

    AJ Schmidt; CH Delegard; KL Silvers; PR Bredt; CD Carlson; EW Hoppe; JC Hayes; DE Rinehart; SR Gano; BM Thornton

    1999-03-24

    The work described in this report involved comprehensive bench-scale testing of nitric acid (HNO{sub 3}) dissolution of actual sludge materials from the Hanford K East (KE) Basin to confirm the baseline chemical pretreatment process. In addition, process monitoring and material balance information was collected to support the development and refinement of process flow diagrams. The testing was performed by Pacific Northwest National Laboratory (PNNL)for the US Department of Energy's Office of Spent Fuel Stabilization (EM-67) and Numatec Hanford Corporation (NHC) to assist in the development of the K Basin Sludge Pretreatment Process. The baseline chemical pretreatment process for K Basin sludge is nitric acid dissolution of all particulate material passing a 1/4-in. screen. The acid-insoluble fraction (residual solids) will be stabilized (possibly by chemical leaching/rinsing and grouting), packaged, and transferred to the Hanford Environmental Restoration Disposal Facility (ERDF). The liquid fraction is to be diluted with depleted uranium for uranium criticality safety and iron nitrate for plutonium criticality safety, and neutralized with sodium hydroxide. The liquid fraction and associated precipitates are to be stored in the Hanford Tank Waste Remediation Systems (TWRS) pending vitrification. It is expected that most of the polychlorinated biphenyls (PCBs), associated with some K Basin sludges, will remain with the residual solids for ultimate disposal to ERDF. Filtration and precipitation during the neutralization step will further remove trace quantities of PCBs within the liquid fraction. The purpose of the work discussed in this report was to examine the dissolution behavior of actual KE Basin sludge materials at baseline flowsheet conditions and validate the.dissolution process step through bench-scale testing. The progress of the dissolution was evaluated by measuring the solution electrical conductivity and concentrations of key species in the dissolver

  10. Effects of Dilute Acid Pretreatment on Cellulose DP and the Relationship Between DP Reduction and Cellulose Digestibility

    SciTech Connect

    Wang, W.; Chen, X.; Tucker, M.; Himmel, M. E.; Johnson, D. K.

    2012-01-01

    The degree of polymerization(DP) of cellulose is considered to be one of the most important properties affecting the enzymatic hydrolysis of cellulose. Various pure cellulosic and biomass materials have been used in a study of the effect of dilute acid treatment on cellulose DP. A substantial reduction in DP was found for all pure cellulosic materials studied even at conditions that would be considered relatively mild for pretreatment. The effect of dilute acid pretreatment on cellulose DP in biomass samples was also investigated. Corn stover pretreated with dilute acid under the most optimal conditions contained cellulose with a DPw in the range of 1600{approx}3500, which is much higher than the level-off DP(DPw 150{approx}300) obtained with pure celluloses. The effect of DP reduction on the saccharification of celluloses was also studied. From this study it does not appear that cellulose DP is a main factor affecting cellulose saccharification.

  11. Effect of thermal, acid, alkaline and alkaline-peroxide pretreatments on the biochemical methane potential and kinetics of the anaerobic digestion of wheat straw and sugarcane bagasse.

    PubMed

    Bolado-Rodríguez, Silvia; Toquero, Cristina; Martín-Juárez, Judit; Travaini, Rodolfo; García-Encina, Pedro Antonio

    2016-02-01

    The effect of thermal, acid, alkaline and alkaline-peroxide pretreatments on the methane produced by the anaerobic digestion of wheat straw (WS) and sugarcane bagasse (SCB) was studied, using whole slurry and solid fraction. All the pretreatments released formic and acetic acids and phenolic compounds, while 5-hydroxymetilfurfural (HMF) and furfural were generated only by acid pretreatment. A remarkable inhibition was found in most of the whole slurry experiments, except in thermal pretreatment which improved methane production compared to the raw materials (29% for WS and 11% for SCB). The alkaline pretreatment increased biodegradability (around 30%) and methane production rate of the solid fraction of both pretreated substrates. Methane production results were fitted using first order or modified Gompertz equations, or a novel model combining both equations. The model parameters provided information about substrate availability, controlling step and inhibitory effect of compounds generated by each pretreatment. PMID:26642223

  12. Effect of phosphoric acid pretreatment of corncobs on the fermentability of Clostridium beijerinckii TISTR 1461 for biobutanol production.

    PubMed

    Boonsombuti, Akarin; Luengnaruemitchai, Apanee; Wongkasemjit, Sujitra

    2015-01-01

    Corncobs pretreated with H2SO4, HNO3, and H3PO4 were compared to evaluate the fermentation ability of Clostridium beijerinckii TISTR 1461 to produce biobutanol via acetone-butanol-ethanol (ABE) fermentation. It was found that the hydrolysate from H3PO4 pretreatment could be used as a substrate without any inhibitor removal methods. However, in terms of sugar yield, it gave the lowest total sugars in both pretreatment and enzymatic hydrolysis. Response surface methodology was applied to optimize enzymatic hydrolysis of the pretreated corncobs. The optimized conditions reduced the consumption of enzymes and hydrolysis time to 7.68 FPU/g biomass and 63.88 hr, respectively, and yielded 51.82 g/L reducing sugars. The Celluclast 1.5 L and Novozyme 188 enzyme ratio were varied to maximize the hydrolyzed sugars. The ABE fermentation, using substrate from phosphoric acid pretreatment of corncobs, with 10 g/L glucose supplementation produced 11.64 g/L of total ABE, which was close to the control experiment using synthetic medium. This study showed that corncobs pretreated with phosphoric acid could potentially be used as a substrate without using a detoxification process. PMID:24678653

  13. Effect of phosphoric acid as a catalyst on the hydrothermal pretreatment and acidogenic fermentation of food waste.

    PubMed

    Shen, Dongsheng; Wang, Kun; Yin, Jun; Chen, Ting; Yu, Xiaoqin

    2016-05-01

    The hydrothermal method was applied to food waste (FW) pretreatment with phosphoric acid as a catalyst. The content of soluble substances such as protein and carbohydrate in the FW increased after the hydrothermal pretreatment with phosphoric acid addition (⩽5%). The SCOD approached approximately 29.0g/L in 5% phosphoric acid group, which is almost 65% more than the original FW. The hydrothermal condition was 160°C for 10min, which means that at least 40% of energy and 60% of reaction time were saved to achieve the expected pretreatment effect. Subsequent fermentation tests showed that the optimal dosage of phosphoric acid was 3% with a VFA yield of 0.763g/gVSremoval, but the increase in salinity caused by phosphoric acid could adversely affect the acidogenesis. With an increase in the quantity of phosphoric acid, among the VFAs, the percentage of propionic acid decreased and that of butyric acid increased. The PCR-DGGE analysis indicated that the microbial diversity could decrease with excessive phosphoric acid, which resulted in a low VFA yield. PMID:26965213

  14. Tissue specific response of Miscanthus×giganteus to dilute acid pretreatment for enhancing cellulose digestibility.

    PubMed

    Ji, Zhe; Zhang, Xun; Ling, Zhe; Sun, Run-Cang; Xu, Feng

    2016-12-10

    The recalcitrance in grasses varies according to cell type and tissue. In this study, dilute acid pretreatment was performed on Miscanthus×giganteus internodes that include rind and pith regions which showing heterogeneous structural and chemical changes. Pretreatment on pith effectively hydrolyzed 73.33% hemicelluloses and separated cohesive cell walls from the compound middle lamella due to lignin migration. Lignin droplets with an average diameter of 49.5±29.3nm were concurrently coalesced on wall surface, that in turn exposed more microfibrils deep in walls to be enzymatically hydrolyzed reaching 82.55%. By contrast, the rind with a relatively intergrated cell structure was covered by larger lignin droplets (101.2±44.1nm) and filled with inaccessible microfibrils limiting enzymatic sacchrification (31.50%). Taken together, the cellulose digestibility of biomass was not majorly influenced by cellulose crystallinity, while it was strongly correlated with the positive effects of hemicelluloses degradation, lignin redistribution, cellulose exposure and loosening cell wall structure. PMID:27577916

  15. Fermentation of Acid-pretreated Corn Stover to Ethanol Without Detoxification Using Pichia stipitis

    NASA Astrophysics Data System (ADS)

    Agbogbo, Frank K.; Haagensen, Frank D.; Milam, David; Wenger, Kevin S.

    In this work, the effect of adaptation on P. stipitis fermentation using acidpretreated corn stover hydrolyzates without detoxification was examined. Two different types of adaptation were employed, liquid hydrolyzate and solid state agar adaptation. Fermentation of 12.5% total solids undetoxified acid-pretreated corn stover was performed in shake flasks at different rotation speeds. At low rotation speed (100 rpm), both liquid hydrolyzate and solid agar adaptation highly improved the sugar consumption rate as well as ethanol production rate compared to the wild-type strains. The fermentation rate was higher for solid agar-adapted strains compared to liquid hydrolyzate-adapted strains. At a higher rotation speed (150 rpm), there was a faster sugar consumption and ethanol production for both the liquid-adapted and the wild-type strains. However, improvements in the fermentation rate between the liquid-adapted and wild strains were less pronounced at the high rotation speed.

  16. Dilute-acid pretreated sugarcane bagasse with fungal treatment and fermentable by Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recovering fermentable sugars from sugarcane bagasse requires a pretreatment followed by enzymatic saccharification. During pretreatment inhibitory compounds are often formed that impede fermenting microorganisms. Biological detoxification has been identified as a potential method to prepare biomass...

  17. Combined Dilute Acid and Solvent Based Pretreatment of Agricultural Wastes for Efficient Lignocellulosic Fractionation and Biofuels Production

    SciTech Connect

    Brodeur, G.; Ramakrishnan, S.; Wilson, C.; Telotte, J.; Collier, J.; Stickel, J.

    2013-01-01

    A true biorefinery for processing lignocellulosic biomass should achieve maximum utilization of all major constituents (cellulose, hemicellulose, & lignin) within the feedstock. In this work a combined pretreatment process of dilute acid (DA) and N-methyl morpholine N-oxide (NMMO) is described that allows for both fractionation and subsequent complete hydrolysis of the feedstocks (corn stover and sugarcane bagasse). During this multi-step processing, the dilute acid pretreatment solubilizes the majority (>90%) of the hemicellulosic fraction, while the NMMO treatment yields a cellulosic fraction that is completely digestible within 48 hours at low enzyme loadings. With both the cellulosic and hemicellulosic fractions being converted into separate, dissolved sugar fractions, the remaining portion is nearly pure lignin. When used independently, DA and NMMO pretreatments are only able to achieve ~80% and ~45% cellulosic conversion, respectively. Mass balance calculations along with experimental results are used to illustrate the feasibility of separation and recycling of NMMO.

  18. Comparison of enzymatic reactivity of corn stover solids prepared by dilute acid, AFEX™, and ionic liquid pretreatments

    PubMed Central

    2014-01-01

    Background Pretreatment is essential to realize high product yields from biological conversion of naturally recalcitrant cellulosic biomass, with thermochemical pretreatments often favored for cost and performance. In this study, enzymatic digestion of solids from dilute sulfuric acid (DA), ammonia fiber expansion (AFEX™), and ionic liquid (IL) thermochemical pretreatments of corn stover were followed over time for the same range of total enzyme protein loadings to provide comparative data on glucose and xylose yields of monomers and oligomers from the pretreated solids. The composition of pretreated solids and enzyme adsorption on each substrate were also measured to determine. The extent glucose release could be related to these features. Results Corn stover solids from pretreatment by DA, AFEX, and IL were enzymatically digested over a range of low to moderate loadings of commercial cellulase, xylanase, and pectinase enzyme mixtures, the proportions of which had been previously optimized for each pretreatment. Avicel® cellulose, regenerated amorphous cellulose (RAC), and beechwood xylan were also subjected to enzymatic hydrolysis as controls. Yields of glucose and xylose and their oligomers were followed for times up to 120 hours, and enzyme adsorption was measured. IL pretreated corn stover displayed the highest initial glucose yields at all enzyme loadings and the highest final yield for a low enzyme loading of 3 mg protein/g glucan in the raw material. However, increasing the enzyme loading to 12 mg/g glucan or more resulted in DA pretreated corn stover attaining the highest longer-term glucose yields. Hydrolyzate from AFEX pretreated corn stover had the highest proportion of xylooligomers, while IL produced the most glucooligomers. However, the amounts of both oligomers dropped with increasing enzyme loadings and hydrolysis times. IL pretreated corn stover had the highest enzyme adsorption capacity. Conclusions Initial hydrolysis yields were highest

  19. Full-scale on-farm pretreatment of perennial grasses with dilute acid for fuel ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Producers utilizing sulfuric acid to pretreat biomass on-farm will need a safe and cost-effective method for application that does not negatively impact the ensiling process or harvesting capacity. To that end, switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were pre...

  20. Effect of dilute acid pretreatment severity on the bioconversion efficiency of Phalaris aquatica L. lignocellulosic biomass into fermentable sugars.

    PubMed

    Pappas, Ioannis A; Koukoura, Zoi; Tananaki, Chrisoula; Goulas, Christos

    2014-08-01

    The effect of dilute acid pretreatment severity on the bioconversion efficiency of Phalaris aquatica lignocellulosic biomass into fermentable sugar monomers was studied. The pretreatment conditions were expressed in a combined severity factor (CSF), ranged from 0.13 to 1.16. The concentration of xylose and total monomeric sugars released from hemicellulose increased with pretreatment as the CSF increased. Dilute acid pretreatment resulted in about 1.7-fold increase in glucose release relative to the untreated biomass, while CSF was positively correlated with glucose recovery. A maximum glucose yield of 85.05% was observed at high severity values (i.e. CSF 1.16) after 72 h. The total amount of sugars released (i.e. xylose and glucose) was increased with pretreatment severity and a maximum conversion efficiency of 76.1% of structural carbohydrates was obtained at a CSF=1. Our data indicated that Phalaris aquatica L. is an alternative bioethanol feedstock and that hemicellulose removal promotes glucose yield. PMID:24929811

  1. Potential of phosphoric acid-catalyzed pretreatment and subsequent enzymatic hydrolysis for biosugar production from Gracilaria verrucosa.

    PubMed

    Kwon, Oh-Min; Kim, Sung-Koo; Jeong, Gwi-Taek

    2016-07-01

    This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications. PMID:27003825

  2. Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

    DOE PAGESBeta

    Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.; Dien, Bruce S.; Kurtzman, Cletus P.; Balan, Venkatesh; da Costa Sousa, Leonardo; Uppugundla, Nirmal; Dale, Bruce E; Cotta, Michael A

    2015-04-09

    Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARSmore » Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.« less

  3. Dewaterability of sludge conditioned with surfactant DDBAC pretreatment by acid/alkali.

    PubMed

    Hong, Chen; Xing, Yi; Hua, Xiufu; Si, Yanxiao; Qiao, Geng; Wang, Zhiqiang

    2015-07-01

    The potential benefits of surfactant-conditioned sludge dewatering treatment with acid/alkali pretreatment were investigated in this study. The water content of dewatered sludge (W C) and specific resistance of filtration (SRF) were used to evaluate sludge dewaterability. Extracellular polymeric substance (EPS) content, bound water content, zeta potential, and rheological properties were measured to explain the change of dewaterability observed in the conditioning process. By introducing dodecyl dimethyl benzyl ammonium chloride (DDBAC), the EPS content of the sludge supernatant changed, and bound water content, charge strength, and apparent viscosity decreased simultaneously. Although DDBAC-conditioned sludge in strong alkaline had low bound water content, W C and SRF increased rapidly because of the dramatically increasing of EPS in sludge supernatant. Remarkable decrement was observed in bound water content and W C in DDBAC-conditioned sludge which was in weak acid environment for comparison. The results indicated that 75 mg/g of DDBAC at pH 4.84 was the optimum under which W C and SRF were at their lowest point in sludge, 58.22 % and 0.521 × 10(13) m/kg, respectively. PMID:25744646

  4. Dilute Sulfuric Acid Pretreatment of Agricultural and Agro-Industrial Residues for Ethanol Production

    NASA Astrophysics Data System (ADS)

    Martin, Carlos; Alriksson, Björn; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

    The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122°C during 20, 40, or 60 min using 2% H2SO4 at a solid-to-liquid ratio of 1∶10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7-to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.

  5. Preparation of highly charged cellulose nanofibrils using high-pressure homogenization coupled with strong acid hydrolysis pretreatments.

    PubMed

    Tian, Cuihua; Yi, Jianan; Wu, Yiqiang; Wu, Qinglin; Qing, Yan; Wang, Lijun

    2016-01-20

    Cellulose nanofibrils (CNFs) are attracting much attention for the advantages of excellent mechanical strength, good optical transparency, and high surface area. An eco-friendly and energy-saving method was created in this work to produce highly negative charged CNFs using high-pressure mechanical defibrillation coupled with strong acid hydrolysis pretreatments. The morphological development, zeta potential, crystal structure, chemical composition and thermal degradation behavior of the resultant materials were evaluated by transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and thermogravimetric analysis (TGA). These CNFs were fully separated, surface-charged, and highly entangled. They showed a large fiber aspect ratio compared to traditional cellulose nanocrystrals that are produced by strong acid hydrolysis. Compared to hydrochloric acid hydrolysis, the CNFs produced by sulfuric acid pretreatments were completely defibrillated and presented stable suspensions (or gels) even at low fiber content. On the other hand, CNFs pretreated by hydrochloric acid hydrolysis trended to aggregate because of the absence of surface charge. The crystallinity index (CI) of CNFs decreased because of mechanical defibrillation, and then increased dramatically with increased sulfuric acid concentration and reaction time. FTIR analysis showed that the C-O-SO3 group was introduced on the surfaces of CNFs during sulfuric acid hydrolysis. These sulfate groups accelerated the thermal degradation of CNFs, which occurred at lower temperature than wood pulp, indicating that the thermal stability of sulfuric acid hydrolyzed CNFs was decreased. The temperature of the maximum decomposition rate (Tmax) and the maximum weight-loss rates (MWLRmax) were much lower than for wood pulp because of the retardant effect of sulfuric acid during the combustion of CNFs. By contrast, the CNFs treated with hydrochloric acid

  6. The Effects of Thermal Pretreatment on Leaching of Yunnan Ilmenite with Hydrochloric Acid

    NASA Astrophysics Data System (ADS)

    Liu, Song-Li; Xiang, Jun-Yi

    2016-04-01

    The effects of thermal pretreatment on the leaching of Yunnan ilmenite ores were investigated from two aspects: the dissolution of iron and titanium, and the proportion of fine precipitations. The results indicate that high-temperature reduction or oxidization produces phase and structure transformations on ilmenite that facilitate the dissolution of iron, reduce the dissolution of titanium, and facilitate the hydrolysis of dissolved titanium. The results further indicate that oxidation at temperatures ranging from 1023 K (750 °C) to 1273 K (1000 °C) can significantly decrease the proportion of fine products. It is believed that the structure of oxidized ilmenite played an important role in minimizing the proportion of fine materials.

  7. Production of 2,3-butanediol from cellulose and Jatropha hulls after ionic liquid pretreatment and dilute-acid hydrolysis

    PubMed Central

    2013-01-01

    Abundant Jatropha waste is a promising renewable feedstock for the production of sugars and 2,3-butanediol fermentation. To obtain high yield of water-soluble products and high concentration of reducing-sugars, ionic liquid (IL) pretreatment and dilute acid hydrolysis at 150°C were combined in this work. The destruction of crystalline structure and increase surface area of biomasses after IL-pretreatment, made their hydrolysis more efficient. Compared with original cellulose, after IL-pretreatment, both the yield and concentration of reducing-sugars increased by 139%, and the water-soluble products yield increased by 128% after hydrolysis. Compared with water-washed Jatropha hulls, after IL-pretreatment, the yield and concentration of reducing-sugars increased by 80% and 76%, respectively, and the water-soluble products yield increased by 70% after hydrolysis. IL-pretreatment benefited the fermentation of Jatropha hull hydrolysate with 66.58% diol yield and its productivity increased from 0.35 to 0.40 g/(L · h). PMID:23958155

  8. Deposition of Lignin Droplets Produced During Dilute Acid Pretreatment of Maize Stems Retards Enzymatic Hydrolysis of Cellulose

    SciTech Connect

    Selig, M. J.; Viamajala, S.; Decker, S. R.; Tucker, M. P.; Himmel, M. E.; Vinzant, T. B.

    2007-01-01

    Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these lignin droplets and the possible implications they might have on the enzymatic saccharification of pretreated biomass. It was demonstrated that these droplets are produced from corn stover during pretreatment under neutral and acidic pH at and above 130C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150C) and captured onto pure cellulose was shown to have a negative effect (5-20%) on the enzymatic saccharification of this substrate. It was noted that droplet density (per unit area) was greater and droplet size more variable under conditions where the greatest impact on enzymatic cellulose conversion was observed. These results indicate that this phenomenon has the potential to adversely affect the efficiency of enzymatic conversion in a lignocellulosic biorefinery.

  9. Epsilon Aminocaproic Acid Pretreatment Provides Neuroprotection Following Surgically Induced Brain Injury in a Rat Model.

    PubMed

    Komanapalli, Esther S; Sherchan, Prativa; Rolland, William; Khatibi, Nikan; Martin, Robert D; Applegate, Richard L; Tang, Jiping; Zhang, John H

    2016-01-01

    Neurosurgical procedures can damage viable brain tissue unintentionally by a wide range of mechanisms. This surgically induced brain injury (SBI) can be a result of direct incision, electrocauterization, or tissue retraction. Plasmin, a serine protease that dissolves fibrin blood clots, has been shown to enhance cerebral edema and hemorrhage accumulation in the brain through disruption of the blood brain barrier. Epsilon aminocaproic acid (EAA), a recognized antifibrinolytic lysine analogue, can reduce the levels of active plasmin and, in doing so, potentially can preserve the neurovascular unit of the brain. We investigated the role of EAA as a pretreatment neuroprotective modality in a SBI rat model, hypothesizing that EAA therapy would protect brain tissue integrity, translating into preserved neurobehavioral function. Male Sprague-Dawley rats were randomly assigned to one of four groups: sham (n = 7), SBI (n = 7), SBI with low-dose EAA, 150 mg/kg (n = 7), and SBI with high-dose EAA, 450 mg/kg (n = 7). SBI was induced by partial right frontal lobe resection through a frontal craniotomy. Postoperative assessment at 24 h included neurobehavioral testing and measurement of brain water content. Results at 24 h showed both low- and high-dose EAA reduced brain water content and improved neurobehavioral function compared with the SBI groups. This suggests that EAA may be a useful pretherapeutic modality for SBI. Further studies are needed to clarify optimal therapeutic dosing and to identify mechanisms of neuroprotection in rat SBI models. PMID:26463967

  10. Strategies to achieve high-solids enzymatic hydrolysis of dilute-acid pretreated corn stover.

    PubMed

    Geng, Wenhui; Jin, Yongcan; Jameel, Hasan; Park, Sunkyu

    2015-01-01

    Three strategies were presented to achieve high solids loading while maximizing carbohydrate conversion, which are fed-batch, splitting/thickening, and clarifier processes. Enzymatic hydrolysis was performed at water insoluble solids (WIS) of 15% using washed dilute-acid pretreated corn stover. The carbohydrate concentration increased from 31.8 to 99.3g/L when the insoluble solids content increased from 5% to 15% WIS, while the final carbohydrate conversion was decreased from 78.4% to 73.2%. For the fed-batch process, a carbohydrate conversion efficiency of 76.8% was achieved when solid was split into 60:20:20 ratio, with all enzymes added first. For the splitting/thickening process, a carbohydrate conversion of 76.5% was realized when the filtrate was recycled to simulate a steady-state process. Lastly, the clarifier process was evaluated and the highest carbohydrate conversion of 81.4% was achieved. All of these results suggests the possibility of enzymatic hydrolysis at high solids to make the overall conversion cost-competitive. PMID:25836373

  11. Acidic pretreatment of wheat straw in decanol for the production of surfactant, lignin and glucose.

    PubMed

    Marinkovic, Sinisa; Le Bras, Jean; Nardello-Rataj, Véronique; Agach, Mickaël; Estrine, Boris

    2012-01-01

    Wheat straw is an abundant residue of agriculture which is increasingly being considered as feedstock for the production of fuels, energy and chemicals. The acidic decanol-based pre-treatment of wheat straw has been investigated in this work. Wheat straw hemicellulose has been efficiently converted during a single step operation into decyl pentoside surfactants and the remaining material has been preserved keeping all its promises as potential feedstock for fuels or value added platform chemicals such as hydroxymethylfurfural (HMF). The enzymatic digestibility of the cellulose contained in the straw residue has been evaluated and the lignin prepared from the material characterized. Wheat-based surfactants thus obtained have exhibited superior surface properties compared to fossil-based polyethoxylates decyl alcohol or alkyl oligoglucosides, some of which are largely used surfactants. In view of the growing importance of renewable resource-based molecules in the chemical industry, this approach may open a new avenue for the conversion of wheat straw into various chemicals. PMID:22312256

  12. Acidic Pretreatment of Wheat Straw in Decanol for the Production of Surfactant, Lignin and Glucose

    PubMed Central

    Marinkovic, Sinisa; Le Bras, Jean; Nardello-Rataj, Véronique; Agach, Mickaël; Estrine, Boris

    2012-01-01

    Wheat straw is an abundant residue of agriculture which is increasingly being considered as feedstock for the production of fuels, energy and chemicals. The acidic decanol-based pre-treatment of wheat straw has been investigated in this work. Wheat straw hemicellulose has been efficiently converted during a single step operation into decyl pentoside surfactants and the remaining material has been preserved keeping all its promises as potential feedstock for fuels or value added platform chemicals such as hydroxymethylfurfural (HMF). The enzymatic digestibility of the cellulose contained in the straw residue has been evaluated and the lignin prepared from the material characterized. Wheat-based surfactants thus obtained have exhibited superior surface properties compared to fossil-based polyethoxylates decyl alcohol or alkyl oligoglucosides, some of which are largely used surfactants. In view of the growing importance of renewable resource-based molecules in the chemical industry, this approach may open a new avenue for the conversion of wheat straw into various chemicals. PMID:22312256

  13. Steam-explosion pretreatment of wood: Effect of chip size, acid, moisture content and pressure drop.

    PubMed

    Brownell, H H; Yu, E K; Saddler, J N

    1986-06-01

    Material balances for pentosan, lignin, and hexosan, during steam-explosion pretreatment of aspenwood, showed almost quantitative recovery of cellulose in the water-insoluble fraction. Dilute acid impregnation resulted in more selective hydrolysis of pentosan relative to undesirable pyrolysis, and gave a more accessible substrate for enzymatic hydrolysis. Thermocouple probes, located inside simulated aspenwood chips heated in 240 degrees C-saturated steam, showed rapid heating of air-dry wood, whereas green or impregnated wood heated slowly. Small chips, 3.2 mm in the fiber direction, whether green or airdry gave approximately equal rates of pentosan destruction and solubilization, and similar yields of glucose and of total reducing sugars on enzymatic hydrolysis with Trichoderma harzianum. Partial pyrolysis, destroying one third of the pentosan of aspenwood at atmospheric pressure by dry steam at 276 degrees C, gave little increase in yield of reducing sugars on enzymatic hydrolysis. Treatment with saturated steam at 240 degrees C gave essentially the same yields of glucose and of total reducing sugars, and the same yields of butanediol and ethanol on fermentation with Klebsiella pneumoniae, whether or not 80% of the steam was bled off before explosion and even if the chips remained intact, showing that explosion was unnecessary. PMID:18555395

  14. Steam-explosion pretreatment of wood: effect of chip size, acid, moisture content and pressure drop

    SciTech Connect

    Brownell, H.H.; Yu, E.K.C.; Saddler, J.N.

    1986-06-01

    Material balances for pentosan, lignin, and hexosan, during steam-explosion pretreatment of aspenwood, showed almost quantitative recovery of cellulose in the water-insoluble fraction. Dilute acid impregnation resulted in more selective hydrolysis of pentosan relative to undesirable pyrolysis, and gave a more accessible substrate for enzymatic hydrolysis. Thermocouple probes, located inside simulated aspenwood chips heated in 240 degrees C-saturated steam, showed rapid heating of air-dry wood, whereas green or impregnated wood heated slowly. Small chips, 3.2 mm in the fiber direction, whether green or air dry gave approximately equal rates of pentosan destruction and solubilization, and similar yields of glucose and of total reducing sugars on enzmatic hydrolysis with Trichoderma harzianum. Partial pyrolysis, destroying one-third of the pentosan of aspenwood at atmospheric pressure by dry steam at 276 degrees C, gave little increase in yield of reducing sugars on enzymatic hydrolysis. Treatment with saturated steam at 240 degrees C gave essentially the same yields of butanediol and ethanol on fermentation with Klebsiella pneumoniae, whether or not 80% of the steam was bled off before explosion and even if the chips remained intact, showing that explosion was unnecessary. 17 references.

  15. Improving enzymatic hydrolysis of corn stover pretreated by ethylene glycol-perchloric acid-water mixture.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Lu, Ting; Ding, Yun; Zhang, Dan-Ping; Qing, Qing; Zhang, Yue

    2015-02-01

    To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol. PMID:25384544

  16. Biological inhibitor abatement and ethanol fermentation of sugars from dilute acid-pretreated rice hulls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fermentation inhibitors arise from lignin, hemicellulose, and degraded sugar during pretreatment of lignocellulosic biomass. Use of a microbe has been explored for abatement of pretreated biomass in which fermentation inhibitors, if left untreated, can complicate microbial conversion of biomass to f...

  17. Increased humoral antibody response of foot-and-mouth disease virus vaccine in growing pigs pre-treated with poly-γ-glutamic acid

    PubMed Central

    Lee, Jee-Hoon; Kang, Ik-Jae; Kim, A-Reum; Noh, You-Sun; Chung, Hee-Chun

    2016-01-01

    This study was conducted to determine if humoral antibody response of foot-and-mouth disease (FMD) vaccine improved in 8-week-old growing pigs born to well-vaccinated sows pre-treated with 60 mg of poly-γ-glutamic acid (γ-PGA) three days before vaccination. Antibody against FMD virus serotype O was measured 0, 2, 4 and 6 weeks post-vaccination, using a PrioCHECK FMDV type O ELISA kit. The results showed that positive antibody reactions against FMDV serotype O antigen among a component of the vaccine significantly increased in response to pre-injection with γ-PGA. PMID:26645341

  18. Increased humoral antibody response of foot-and-mouth disease virus vaccine in growing pigs pre-treated with poly-γ-glutamic acid.

    PubMed

    Lee, Jee-Hoon; Kang, Ik-Jae; Kim, A-Reum; Noh, You-Sun; Chung, Hee-Chun; Park, Bong-Kyun

    2016-06-30

    This study was conducted to determine if humoral antibody response of foot-and-mouth disease (FMD) vaccine improved in 8-week-old growing pigs born to well-vaccinated sows pre-treated with 60 mg of poly-γ-glutamic acid (γ-PGA) three days before vaccination. Antibody against FMD virus serotype O was measured 0, 2, 4 and 6 weeks post-vaccination, using a PrioCHECK FMDV type O ELISA kit. The results showed that positive antibody reactions against FMDV serotype O antigen among a component of the vaccine significantly increased in response to pre-injection with γ-PGA. PMID:26645341

  19. The significance of plasma phytanic acid levels in adults.

    PubMed Central

    Britton, T C; Gibberd, F B; Clemens, M E; Billimoria, J D; Sidey, M C

    1989-01-01

    The presence of phytanic acid in tissues and plasma has been considered diagnostic of heredopathia atactica polyneuritiformis (Refsum's disease), but recently slightly raised plasma phytanic acid levels have been reported in other conditions. Forty two normal people were found to have a phytanic acid level of 0-33 mumol/l. Fourteen patients with heredopathia atactica polyneuritiformis had a plasma phytanic acid level before treatment of 992-6400 mumol/l. Five patients with retinitis pigmentosa but not heredopathia atactica polyneuritiformis had plasma levels of 38-192 mumol/l. It was concluded that some patients with retinitis pigmentosa without heredopathia atactica polyneuritiformis but a raised plasma phytanic acid may represent a group of patients with a disease or diseases as yet uncharacterised apart from the retinal condition. PMID:2475586

  20. Use of Empty Fruit Bunches from the oil palm for bioethanol production: a thorough comparison between dilute acid and dilute alkali pretreatment.

    PubMed

    Chiesa, S; Gnansounou, E

    2014-05-01

    In the present work, two pretreatment techniques using either dilute acid (H2SO4) or dilute alkali (NaOH) have been compared for producing bioethanol from Empty Fruit Bunches (EFBs) from oil palm tree, a relevant feedstock for tropical countries. Treatments' performances under different conditions have been assessed and statistically optimized with respect to the response upon standardized enzymatic saccharification. The dilute acid treatment performed at optimal conditions (161.5°C, 9.44 min and 1.51% acid loading) gave 85.5% glucose yield, comparable to those of other commonly investigated feedstocks. Besides, the possibility of using fibers instead of finely ground biomass may be of economic interest. Oppositely, treatment with dilute alkali has shown lower performances under the conditions explored, most likely given the relatively significant lignin content, suggesting that the use of stronger alkali regime (with the associated drawbacks) is unavoidable to improve the performance of this treatment. PMID:24662312

  1. Injection of air into the headspace improves fermentation of phosphoric acid pretreated sugarcane bagasse by Escherichia coli MM170.

    PubMed

    Nieves, I U; Geddes, C C; Mullinnix, M T; Hoffman, R W; Tong, Z; Castro, E; Shanmugam, K T; Ingram, L O

    2011-07-01

    Microaeration (injecting air into the headspace) improved the fermentation of hemicellulose hydrolysates obtained from the phosphoric acid pretreatment of sugarcane bagasse at 170°C for 10 min. In addition, with 10% slurries of phosphoric acid pretreated bagasse (180°C, 10 min), air injection into the headspace promoted xylose utilization and increased ethanol yields from 0.16 to 0.20 g ethanol/g bagasse dry weight using a liquefaction plus simultaneous saccharification and co-fermentation process (L+SScF). This process was scaled up to 80 L using slurries of acid pretreated bagasse (96 h incubation; 0.6L of air/min into the headspace) with ethanol yields of 312-347 L (82-92 gal) per tone (dry matter), corresponding to 0.25 and 0.27 g/g bagasse (dry weight). Injection of small amounts of air into the headspace may provide a convenient alternative to subsurface sparging that avoids problems of foaming, sparger hygiene, flotation of particulates, and phase separation. PMID:21531547

  2. Effects of acid/alkaline pretreatment and gamma-ray irradiation on extracellular polymeric substances from sewage sludge

    NASA Astrophysics Data System (ADS)

    Xie, Shuibo; Wu, Yuqi; Wang, Wentao; Wang, Jingsong; Luo, Zhiping; Li, Shiyou

    2014-04-01

    In order to investigate the mechanism of extracellular polymeric substances (EPS) influencing sludge characteristics, variations of extractable EPS from municipal sewage sludge by acid/alkaline pretreatment and gamma-ray irradiation were studied. The changes in constituents of EPS were analyzed by UV-vis spectra and SEM images. The effects of alkaline pretreatment and gamma-ray irradiation on the functional groups in EPS were investigated by Fourier transform infrared (FTIR) spectrometer. Results showed that the extractable EPS increased clearly with increasing irradiation dose from 0 to 15 kGy. UV-vis spectra indicated that a new absorption band from 240 nm to 300 nm existed in all irradiated samples, apart from acid condition. The results of FTIR spectroscopic analysis indicated that, irradiation influenced major functional groups in EPS, such as protein and polysaccharide, and these effects were clearer under alkaline condition. SEM images provided that after alkaline hydrolysis, gamma-ray irradiation was more effective in resulting in the sludge flocs and cells broken, compared with acid pretreatment (pH 2.50).

  3. Hydrolysis of Miscanthus for bioethanol production using dilute acid presoaking combined with wet explosion pre-treatment and enzymatic treatment.

    PubMed

    Sørensen, Annette; Teller, Philip J; Hilstrøm, Troels; Ahring, Birgitte K

    2008-09-01

    Miscanthus is a high yielding bioenergy crop. In this study we used acid presoaking, wet explosion, and enzymatic hydrolysis to evaluate the combination of the different pre-treatment methods for bioethanol production with Miscanthus. Acid presoaking is primarily carried out in order to remove xylose prior to wet explosion. The acid presoaking extracted 63.2% xylose and 5.2% glucose. Direct enzymatic hydrolysis of the presoaked biomass was found to give only low sugar yields of 24-26% glucose. Wet explosion is a pre-treatment method that combines wet-oxidation and steam explosion. The effect of wet explosion on non-presoaked and presoaked Miscanthus was investigated using both atmospheric air and hydrogen peroxide as the oxidizing agent. All wet explosion pre-treatments showed to have a disrupting effect on the lignocellulosic biomass, making the sugars accessible for enzymatic hydrolysis. The combination of presoaking, wet explosion, and enzymatic hydrolysis was found to give the highest sugar yields. The use of atmospheric air gave the highest xylose yield (94.9% xylose, 61.3% glucose), while hydrogen peroxide gave the highest glucose yield (82.4% xylose, 63.7% glucose). PMID:18164954

  4. Aiming for the complete utilization of sugar-beet pulp: Examination of the effects of mild acid and hydrothermal pretreatment followed by enzymatic digestion

    PubMed Central

    2011-01-01

    Background Biomass use for the production of bioethanol or platform chemicals requires efficient breakdown of biomass to fermentable monosaccharides. Lignocellulosic feedstocks often require physicochemical pretreatment before enzymatic hydrolysis can begin. The optimal pretreatment can be different for different feedstocks, and should not lead to biomass destruction or formation of toxic products. Methods We examined the influence of six mild sulfuric acid or water pretreatments at different temperatures on the enzymatic degradability of sugar-beet pulp (SBP). Results We found that optimal pretreatment at 140°C of 15 minutes in water was able to solubilize 60% w/w of the total carbohydrates present, mainly pectins. More severe treatments led to the destruction of the solubilized sugars, and the subsequent production of the sugar-degradation products furfural, hydroxymethylfurfural, acetic acid and formic acid. The pretreated samples were successfully degraded enzymatically with an experimental cellulase preparation. Conclusions In this study, we found that pretreatment of SBP greatly facilitated the subsequent enzymatic degradation within economically feasible time ranges and enzyme levels. In addition, pretreatment of SBP can be useful to fractionate functional ingredients such as arabinans and pectins from cellulose. We found that the optimal combined severity factor to enhance the enzymatic degradation of SBP was between log R'0 = -2.0 and log R'0 = -1.5. The optimal pretreatment and enzyme treatment solubilized up to 80% of all sugars present in the SBP, including ≥90% of the cellulose. PMID:21627804

  5. Assessment of free nitrous acid pre-treatment on a mixture of primary sludge and waste activated sludge: Effect of exposure time and concentration.

    PubMed

    Zahedi, S; Icaran, P; Yuan, Z; Pijuan, M

    2016-09-01

    Free nitrous acid (FNA) has been shown to enhance the biodegradability of waste activated sludge (WAS) but its effectiveness on the pre-treatment of mixed sludge is not known. This study explores the effectiveness of four different FNA concentrations (0, 2.49, 3.55, 4.62mgN-HNO2/L) and three exposure times (2, 5, 9h) lower than the ones reported in literature (24h) on WAS characteristics and specific methane production (SMP). FNA pre-treatment reduced sludge cell viability below 10% in all cases after an exposure time of 5h, increasing the solubility of the organic matter. The treated mixed sludge was used as substrate for the biochemical methane production tests to assess its SMP. Results showed a significant increase (up to 25%) on SMP when the sludge was pretreated with the lowest FNA concentration (2.49mgN-HNO2/L) during 2 and 5h but did not show any improvement at longer exposure times or higher FNA concentrations. PMID:27318660

  6. Pretreatment of spent sulphite liquor via ultrafiltration and nanofiltration for bio-based succinic acid production.

    PubMed

    Pateraki, Chrysanthi; Ladakis, Dimitrios; Stragier, Lutgart; Verstraete, Willy; Kookos, Ioannis; Papanikolaou, Seraphim; Koutinas, Apostolis

    2016-09-10

    Ultrafiltration and nanofiltration of spent sulphite liquor (SSL) has been employed to evaluate the simultaneous production of lignosulphonates and bio-based succinic acid using the bacterial strains Actinobacillus succinogenes and Basfia succiniciproducens. Ultrafiltration with membranes of 10, 5 and 3kDa molecular weight cut-off results in significant losses of lignosulphonates (26-50%) in the permeate stream, while nanofiltration using membrane with 500Da molecular weight cut-off results in high retention yields of lignosulphonates (95.6%) in the retentate stream. Fed-batch bioreactor cultures using permeates from ultrafiltrated SSL resulted in similar succinic acid concentration (27.5g/L) and productivity (0.4g/L/h) by both strains. When permeates from nanofiltrated SSL were used, the strain B. succiniciproducens showed the highest succinic acid concentration (33.8g/L), yield (0.58g per g of consumed sugars) and productivity (0.48g/L/h). The nanofiltration of 1t of thick spent sulphite liquor could lead to the production of 306.3kg of lignosulphonates and 52.7kg of succinic acid, whereas the ultrafiltration of 1t of thick spent sulphite liquor using a 3kDa membrane could result in the production of 237kg of lignosulphonates and 71.8kg of succinic acid when B. succiniproducens is used in both cases. PMID:27374402

  7. Unraveling the Structural Modifications in Lignin of Arundo donax Linn. during Acid-Enhanced Ionic Liquid Pretreatment.

    PubMed

    You, Tingting; Zhang, Liming; Guo, Siqin; Shao, Lupeng; Xu, Feng

    2015-12-23

    Solid acid-enhanced ionic liquid (IL) pretreatment is of paramount importance for boosting the yield of sugars from biomass cost-effectively and environmentally friendly. To unravel the chemical and supramolecular structural changes of lignin after pretreatment, IL-acid lignin (ILAL) and subsequent residual cellulolytic enzyme lignin (RCEL) were isolated from Arundo donax Linn. The structural features were compared with those of the corresponding milled wood lignin (MWL). Results indicated that the pretreatment caused loss of β-O-4', β-β', β-1' linkages and formation of condensed structures in lignin. A preferential breakdown of G-type lignin may have occurred, evidenced by an increased S/G ratio revealed by 2D HSQC NMR analysis. It was determined that the depolymerization of β-O-4' linkage, lignin recondensation, and cleavage of ferulate-lignin ether linkages took place. Moreover, a simulation module was first developed to define morphological changes in lignin based on AFM and TEM analyses. Briefly, tree branch like aggregates was destroyed to monodisperse particles. PMID:26621450

  8. Analysis of the low-pressure plasma pretreated polymer surface in terms of acid-base approach

    NASA Astrophysics Data System (ADS)

    Kraus, Eduard; Orf, Lukas; Baudrit, Benjamin; Heidemeyer, Peter; Bastian, Martin; Bonenberger, Ramona; Starostina, Irina; Stoyanov, Oleg

    2016-05-01

    We demonstrate the use of a modern wetting method for determining the acid-base properties of treated polymer surfaces for different plastics and adhesives. The effect of the surface treatment with low pressure plasma was evaluated from the viewpoint of acid-base approach with plastics polyoxymethylene (POM) and polyetheretherketone (PEEK). The correlations between the acid-base properties and the identified mechanical tensile strengths of adhesive bonded joints were evaluated and discussed. In the investigated range the determination coefficients for POM and PEEK were calculated to R2 = 0.93 and R2 = 0.97, respectively. These relatively high determination coefficients showed a good correlation between the mechanical strength and the acidity parameter ΔDshort for use in bonding technology for surface pretreatment of polymers with LPP.

  9. Evolved strains of Scheffersomyces stipitis achieving high ethanol productivity on acid- and base-pretreated biomass hydrolyzate at high solids loading

    SciTech Connect

    Slininger, Patricia J.; Shea-Andersh, Maureen A.; Thompson, Stephanie R.; Dien, Bruce S.; Kurtzman, Cletus P.; Balan, Venkatesh; da Costa Sousa, Leonardo; Uppugundla, Nirmal; Dale, Bruce E; Cotta, Michael A

    2015-04-09

    Lignocellulosic biomass is an abundant, renewable feedstock useful for the production of fuel-grade ethanol via the processing steps of pretreatment, enzyme hydrolysis, and microbial fermentation. Traditional industrial yeasts do not ferment xylose and are not able to grow, survive, or ferment in concentrated hydrolyzates that contain enough sugar to support economical ethanol recovery since they are laden with toxic byproducts generated during pretreatment. Repetitive culturing in two types of concentrated hydrolyzates was applied along with ethanol challenged xylose-fed continuous culture to force targeted evolution of the native pentose fermenting yeast Scheffersomyces (Pichia) stipitis strain NRRL Y-7124 maintained in the ARS Culture Collection, Peoria, IL. Isolates collected from various enriched populations were screened and ranked based on relative xylose uptake rate and ethanol yield. Ranking on hydrolyzates with and without nutritional supplementation was used to identify those isolates with best performance across diverse conditions. Robust S. stipitis strains adapted to perform very well in enzyme hydrolyzates of high solids loading ammonia fiber expansion-pretreated corn stover (18% weight per volume solids) and dilute sulfuric acid-pretreated switchgrass (20% w/v solids) were obtained. Improved features include reduced initial lag phase preceding growth, significantly enhanced fermentation rates, improved ethanol tolerance and yield, reduced diauxic lag during glucose-xylose transition, and ability to accumulate >40 g/L ethanol in <167 h when fermenting hydrolyzate at low initial cell density of 0.5 absorbance units and pH 5 to 6.

  10. Impact of acid and alkaline pretreatments on the molecular network of wheat gluten and on the mechanical properties of compression-molded glassy wheat gluten bioplastics.

    PubMed

    Jansens, Koen J A; Lagrain, Bert; Brijs, Kristof; Goderis, Bart; Smet, Mario; Delcour, Jan A

    2013-10-01

    Wheat gluten can be converted into rigid biobased materials by high-temperature compression molding at low moisture contents. During molding, a cross-linked protein network is formed. This study investigated the effect of mixing gluten with acid/alkali in 70% ethanol at ambient temperature for 16 h followed by ethanol removal, freeze-drying, and compression molding at 130 and 150 °C on network formation and on types of cross-links formed. Alkaline pretreatment (0-100 mmol/L sodium hydroxide or 25 mmol/L potassium hydroxide) strongly affected gluten cross-linking, whereas acid pretreatment (0-25 mmol/L sulfuric acid or 25 mmol/L hydrochloric acid) had limited effect on the gluten network. Molded alkaline-treated gluten showed enhanced cross-linking but also degradation when treated with high alkali concentrations, whereas acid treatment reduced gluten cross-linking. β-Elimination of cystine and lanthionine formation occurred more pronouncedly at higher alkali concentrations. In contrast, formation of disulfide and nondisulfide cross-links during molding was hindered in acid-pretreated gluten. Bioplastic strength was higher for alkali than for acid-pretreated samples, whereas the flexural modulus was only slightly affected by either alkaline or acid pretreatment. Apparently, the ratio of disulfide to nondisulfide cross-links did not affect the mechanical properties of rigid gluten materials. PMID:24016229

  11. Improved ethanol yield and reduced minimum ethanol selling price (MESP) by modifying low severity dilute acid pretreatment with deacetylation and mechanical refining: 2) Techno-economic analysis

    PubMed Central

    2012-01-01

    Background Our companion paper discussed the yield benefits achieved by integrating deacetylation, mechanical refining, and washing with low acid and low temperature pretreatment. To evaluate the impact of the modified process on the economic feasibility, a techno-economic analysis (TEA) was performed based on the experimental data presented in the companion paper. Results The cost benefits of dilute acid pretreatment technology combined with the process alternatives of deacetylation, mechanical refining, and pretreated solids washing were evaluated using cost benefit analysis within a conceptual modeling framework. Control cases were pretreated at much lower acid loadings and temperatures than used those in the NREL 2011 design case, resulting in much lower annual ethanol production. Therefore, the minimum ethanol selling prices (MESP) of the control cases were $0.41-$0.77 higher than the $2.15/gallon MESP of the design case. This increment is highly dependent on the carbohydrate content in the corn stover. However, if pretreatment was employed with either deacetylation or mechanical refining, the MESPs were reduced by $0.23-$0.30/gallon. Combing both steps could lower the MESP further by $0.44 ~ $0.54. Washing of the pretreated solids could also greatly improve the final ethanol yields. However, the large capital cost of the solid–liquid separation unit negatively influences the process economics. Finally, sensitivity analysis was performed to study the effect of the cost of the pretreatment reactor and the energy input for mechanical refining. A 50% cost reduction in the pretreatment reactor cost reduced the MESP of the entire conversion process by $0.11-$0.14/gallon, while a 10-fold increase in energy input for mechanical refining will increase the MESP by $0.07/gallon. Conclusion Deacetylation and mechanical refining process options combined with low acid, low severity pretreatments show improvements in ethanol yields and calculated MESP for cellulosic

  12. Summary of Findings from the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI): Corn Stover Pretreatment

    SciTech Connect

    Elander, R. T.; Dale, B. E.; Holtzapple, M.; Ladisch, M. R.; Lee, Y. Y.; Mitchinson, C.; Saddler, J. N.; Wyman, C. E.

    2009-01-01

    The Biomass Refining Consortium for Applied Fundamentals and Innovation, with members from Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, Texas A&M University, the University of British Columbia, and the University of California at Riverside, has developed comparative data on the conversion of corn stover to sugars by several leading pretreatment technologies. These technologies include ammonia fiber expansion pretreatment, ammonia recycle percolation pretreatment, dilute sulfuric acid pretreatment, flowthrough pretreatment (hot water or dilute acid), lime pretreatment, controlled pH hot water pretreatment, and sulfur dioxide steam explosion pretreatment. Over the course of two separate USDA- and DOE-funded projects, these pretreatment technologies were applied to two different corn stover batches, followed by enzymatic hydrolysis of the remaining solids from each pretreatment technology using identical enzyme preparations, enzyme loadings, and enzymatic hydrolysis assays. Identical analytical methods and a consistent material balance methodology were employed to develop comparative sugar yield data for each pretreatment and subsequent enzymatic hydrolysis. Although there were differences in the profiles of sugar release, with the more acidic pretreatments releasing more xylose directly in the pretreatment step than the alkaline pretreatments, the overall glucose and xylose yields (monomers + oligomers) from combined pretreatment and enzymatic hydrolysis process steps were very similar for all of these leading pretreatment technologies. Some of the water-only and alkaline pretreatment technologies resulted in significant amounts of residual xylose oligomers still remaining after enzymatic hydrolysis that may require specialized enzyme preparations to fully convert xylose oligomers to monomers.

  13. Excellent anti-corrosive pretreatment layer on iron substrate based on three-dimensional porous phytic acid/silane hybrid

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Lu, Ke; Xu, Lei; Xu, Hua; Lu, Haifeng; Gao, Feng; Hou, Shifeng; Ma, Houyi

    2016-01-01

    A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely NaBrO3-free and NaBrO3-doped PAS layers, were fabricated on iron substrates using the dip-coating method. SEM and AFM observations showed that the as-fabricated PAS-based layers possessed a 3D porous microstructure at the nanoscale and a rough surface morphology. X-ray photoelectron spectroscopic (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopic characterization demonstrated that the above PAS layers bound to the iron surface via the -P-O- bond. Moreover, analyses of steady-state polarization curves and electrochemical impedance spectroscopic (EIS) data indicated that the corrosion rates of the iron substrates decreased considerably in the presence of the two PAS-based pretreatment layers. In particular, the NaBrO3-dosed PAS layer displayed the better corrosion resistance ability as well as maintaining the original microstructure and surface morphology. The PAS-based pretreatment layers are expected to act as substitutes for chromate and phosphate conversion layers and will find widespread application in the surface pretreatment of iron and steel materials due to the advantages of being environmentally friendly, the rapid film-forming process, and, especially, the nanoporous microstructure and rough surface morphology.A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely Na

  14. Excellent anti-corrosive pretreatment layer on iron substrate based on three-dimensional porous phytic acid/silane hybrid.

    PubMed

    Gao, Xiang; Lu, Ke; Xu, Lei; Xu, Hua; Lu, Haifeng; Gao, Feng; Hou, Shifeng; Ma, Houyi

    2016-01-21

    A novel, highly effective and environmentally friendly film-forming material, phytic acid (PA)/silane (denoted as PAS) hybrid with a three-dimensional (3D) network structure, was prepared through a condensation reaction of PA with methyltrihydroxysilane generated from the hydrolysis of methyltriethoxysilane (MTES). Two kinds of PAS-based pretreatment layers, namely NaBrO3-free and NaBrO3-doped PAS layers, were fabricated on iron substrates using the dip-coating method. SEM and AFM observations showed that the as-fabricated PAS-based layers possessed a 3D porous microstructure at the nanoscale and a rough surface morphology. X-ray photoelectron spectroscopic (XPS) and attenuated total reflection infrared (ATR-IR) spectroscopic characterization demonstrated that the above PAS layers bound to the iron surface via the -P-O- bond. Moreover, analyses of steady-state polarization curves and electrochemical impedance spectroscopic (EIS) data indicated that the corrosion rates of the iron substrates decreased considerably in the presence of the two PAS-based pretreatment layers. In particular, the NaBrO3-dosed PAS layer displayed the better corrosion resistance ability as well as maintaining the original microstructure and surface morphology. The PAS-based pretreatment layers are expected to act as substitutes for chromate and phosphate conversion layers and will find widespread application in the surface pretreatment of iron and steel materials due to the advantages of being environmentally friendly, the rapid film-forming process, and, especially, the nanoporous microstructure and rough surface morphology. PMID:26689810

  15. Acidic and alkaline pretreatments of activated carbon and their effects on the performance of air-cathodes in microbial fuel cells.

    PubMed

    Wang, Xin; Gao, Ningshengjie; Zhou, Qixing; Dong, Heng; Yu, Hongbing; Feng, Yujie

    2013-09-01

    Activated carbon (AC) is a high performing and cost effective catalyst for oxygen reduction reactions (ORRs) of air-cathodes in microbial fuel cells (MFCs). Acidic (HNO3) and alkaline (KOH) pretreatments on AC at low temperature (85°C) are conducted to enhance the performance of MFCs. The alkaline pretreatment increased the power density by 16% from 804±70 to 957±31 mW m(-2), possibly due to the decrease of ohmic resistance (from 20.58 to 19.20 Ω) and the increase of ORR activities provided by the adsorbed hydroxide ion and extra micropore area/volume after alkaline pretreatment. However, acidic pretreatment decreased the power output to 537±36 mW m(-2), which can be mainly attributed to the corrosion by adsorbed proton at the interface of AC powder and stainless steel mesh and the decreased pore area. PMID:23890977

  16. Prognostic Significance of Uric Acid Levels in Ischemic Stroke Patients.

    PubMed

    Zhang, Xia; Huang, Zhi-Chao; Lu, Tao-Sheng; You, Shou-Jiang; Cao, Yong-Jun; Liu, Chun-Feng

    2016-01-01

    The importance and function of serum uric acid (UA) levels in patients with cardiovascular disease or stroke are unclear. We sought to evaluate the appropriate UA levels for stroke patients and the association between endogenous UA levels and clinical outcomes in acute ischemic stroke (AIS) patients, particularly regarding the possible interaction between gender and UA levels with respect to AIS prognosis. We examined 303 patients who had an onset of ischemic stroke within 48 h. Of those, 101 patients received thrombolytic treatment. Serum UA (μmol/L) levels were measured the second morning after admission. Patient prognosis was evaluated 90 days after clinical onset by modified Rankin Scale. Patients were divided into four groups according to serum UA quartiles. A binary multivariate logistic regression model was used to assess clinical relevance in regard to functional outcome and endogenous UA levels. Analysis of subgroups by gender and normal glomerular filtration rate were also been done. Poor functional outcome was associated with older age, history of atrial fibrillation, or higher baseline National Institutes of Health Stroke Scale scores. After adjustment for potential confounders, patients with higher UA levels (>380 μmol/L) or lower UA levels (≤250 μmol/L) were 2-3 times more likely to have a poor outcome (OR 2.95, 95% CI 1.14-7.61; OR 2.78, 95% CI 1.02-7.58, respectively) compared to the baseline group (UA level 316-380 μmol/L). The same results were observed in thrombolyzed patients. Patients with high and low UA levels were 9-18 times more likely to having poor outcomes compared to the baseline group (UA level: 316-380 μmol/L; OR 18.50, 95% CI: 2.041-167.67; OR 9.66, 95% CI 1.42-65.88, respectively). In men, patients with high UA levels were 6 times more likely to have poor outcomes compared to the baseline group (UA level: 279-334 μmol/L; OR 6.10, 95% CI 1.62-22.93). However, female patients with UA level 271-337 μmol/L were seven times more

  17. Nonhazardous Urine Pretreatment Method

    NASA Technical Reports Server (NTRS)

    Akse, James R.; Holtsnider, John T.

    2012-01-01

    A method combines solid phase acidification with two non-toxic biocides to prevent ammonia volatilization and microbial proliferation. The safe, non-oxidizing biocide combination consists of a quaternary amine and a food preservative. This combination has exhibited excellent stabilization of both acidified and unacidified urine. During pretreatment tests, composite urine collected from donors was challenged with a microorganism known to proliferate in urine, and then was processed using the nonhazardous urine pre-treatment method. The challenge microorganisms included Escherichia coli, a common gram-negative bacteria; Enterococcus faecalis, a ureolytic gram-positive bacteria; Candida albicans, a yeast commonly found in urine; and Aspergillus niger, a problematic mold that resists urine pre-treatment. Urine processed in this manner remained microbially stable for over 57 days. Such effective urine stabilization was achieved using non-toxic, non-oxidizing biocides at higher pH (3.6 to 5.8) than previous methods in use or projected for use aboard the International Space Station (ISS). ISS urine pretreatment methods employ strong oxidants including ozone and hexavalent chromium (Cr(VI)), a carcinogenic material, under very acidic conditions (pH = 1.8 to 2.4). The method described here offers a much more benign chemical environment than previous pretreatment methods, and will lower equivalent system mass (ESM) by reducing containment volume and mass, system complexity, and crew time needed to handle pre-treatment chemicals. The biocides, being non-oxidizing, minimize the potential for chemical reactions with urine constituents to produce volatile, airborne contaminants such as cyanogen chloride. Additionally, the biocides are active under significantly less acidic conditions than those used in the current system, thereby reducing the degree of required acidification. A simple flow-through solid phase acidification (SPA) bed is employed to overcome the natural buffering

  18. Thermopressurized diluted phosphoric acid pretreatment of ligno(hemi)cellulose to make free sugars and nutraceutical oligosaccharides.

    PubMed

    Tiboni, Marcela; Grzybowski, Adelia; Baldo, Gizele Rejane; Dias, Edson Flausino; Tanner, Robert D; Kornfield, Julia Ann; Fontana, José Domingos

    2014-06-01

    Ligno(hemi)cellulosics (L(h)Cs) as sugarcane bagasse and loblolly pine sawdust are currently being used to produce biofuels such as bioethanol and biobutanol through fermentation of free sugars that are often obtained enzymatically. However, this bioconversion requires a pretreatment to solubilize the hemicellulose fractions, thus facilitating the action of the cellulolytic enzymes. Instead of the main free monosaccharides used in these current models, the modulation of thermopressurized orthophosphoric acid as a pretreatment, in the ranges of 3-12 atm and pH 1.5-2.5, can produce nondigestible oligosaccharides (NDOS) such as xylo-oligosaccharides (XOS) because heteroxylan is present in both types of hardwood and softwood hemicelluloses. A comparative thin-layer chromatographic analysis of the hydrolytic products showed the best conditions for NDOS production to be 7 atm/water, pH 2.25 and 2.50, and 8.5 atm/water for both sources. Particular hydrolysates from 7 atm (171 °C) at pHs 2.25 and 2.50 both for cane bagasse and pine sawdust, with respective oligosaccharide contents of 57 and 59 %, once mixed in a proportion of 1:1 for each plant source, were used in vitro as carbon sources for Bifidobacterium or Lactobacillus. Once both bacteria attained the stationary phase of growth, an unforeseen feature emerged: the preference of B. animalis for bagasse hydrolysates and, conversely, the preference of L. casei for pine hydrolysates. Considering the fact that nutraceutical oligosaccharides from both hemicelluloses correspond to higher value-added byproducts, the technology using a much diluted thermopressurized orthophosphoric acid pretreatment becomes an attractive choice for L(h)Cs. PMID:24747989

  19. Thermal pretreatment of olive mill wastewater for efficient methane production: control of aromatic substances degradation by monitoring cyclohexane carboxylic acid.

    PubMed

    Pontoni, Ludovico; d'Antonio, Giuseppe; Esposito, Giovanni; Fabbricino, Massimiliano; Frunzo, Luigi; Pirozzi, Francesco

    2015-01-01

    Anaerobic digestion is investigated as a sustainable depurative strategy of olive oil mill wastewater (OOMW). The effect of thermal pretreatment on the anaerobic biodegradation of aromatic compounds present in (OMWW) was investigated. The anaerobic degradation of phenolic compounds, well known to be the main concern related to this kind of effluents, was monitored in batch anaerobic tests at a laboratory scale on samples pretreated at mild (80±1 °C), intermediate (90±1 °C) and high temperature (120±1 °C). The obtained results showed an increase of 34% in specific methane production (SMP) for OMWW treated at the lowest temperature and a decrease of 18% for treatment at the highest temperature. These results were related to the different decomposition pathways of the lignocellulosic compounds obtained in the tested conditions. The decomposition pathway was determined by measuring the concentrations of volatile organic acids, phenols, and chemical oxygen demand (COD) versus time. Cyclohexane carboxylic acid (CHCA) production was identified in all the tests with a maximum concentration of around 200 µmol L(-1) in accordance with the phenols degradation, suggesting that anaerobic digestion of aromatic compounds follows the benzoyl-CoA pathway. Accurate monitoring of this compound was proposed as the key element to control the process evolution. The total phenols (TP) and total COD removals were, with SMP, the highest (TP 62.7%-COD 63.2%) at 80 °C and lowest (TP 44.9%-COD 32.2%) at 120 °C. In all cases, thermal pretreatment was able to enhance the TP removal ability (up to 42% increase). PMID:25624137

  20. Oil production by oleaginous yeasts using the hydrolysate from pretreatment of wheat straw with dilute sulfuric acid.

    PubMed

    Yu, Xiaochen; Zheng, Yubin; Dorgan, Kathleen M; Chen, Shulin

    2011-05-01

    This paper explores the use of the hydrolysate from the dilute sulfuric acid pretreatment of wheat straw for microbial oil production. The resulting hydrolysate was composed of pentoses (24.3g/L) and hexoses (4.9 g/L), along with some other degradation products, such as acetic acid, furfural, and hydroxymethylfurfural (HMF). Five oleaginous yeast strains, Cryptococcus curvatus, Rhodotorula glutinis, Rhodosporidium toruloides, Lipomyces starkeyi, and Yarrowia lipolytica, were evaluated by using this hydrolysate as substrates. The results showed that all of these strains could use the detoxified hydrolysate to produce lipids while except R. toruloides non-detoxified hydrolysate could also be used for the growth of all of the selective yeast strains. C. curvatus showed the highest lipid concentrations in medium on both the detoxified (4.2g/L) and non-detoxified (5.8 g/L) hydrolysates. And the inhibitory effect studies on C. curvatus indicated HMF had insignificant impacts at a concentration of up to 3g/L while furfural inhibited cell growth and lipid content by 72.0% and 62.0% at 1g/L, respectively. Our work demonstrates that lipid production is a promising alternative to utilize hemicellulosic sugars obtained during pretreatment of lignocellulosic materials. PMID:21463940

  1. Optimization of reverse-flow, two-temperature, dilute-acid pretreatment to enhance biomass conversion to ethanol

    SciTech Connect

    Torget, R.; Hatzis, C.; Hayward, T.K.

    1996-12-31

    A reverse-flow, two-temperature dilute-acid prehydrolysis process of commercial yellow poplar sawdust using two percolation reactors was designed to simulate countercurrent flow of the biomass solids and prehydrolysis liquor, and to exploit the xylan biphasic kinetics. Lower temperatures (150-174{degrees}C) are initially applied to hydrolyze the easily hydrolyzable xylan, and higher temperatures (180-204{degrees}C) are applied to hydrolyze the remaining xylan. Two reactors were used to optimize each temperature range, using varying concentrations of sulfuric acid from 0.073-0.73 wt% and reaction times. Yields of soluble xylose, as high as 97% of theoretical, expressed as monomeric and oligomeric xylose, have been achieved with only 2.9% of the xylan being degraded to furfural, at concentrations of total potential sugar between 2.4 and 3.7 wt% before flashing. Depending on the combined severity of the acid concentration, residence time of the solids and liquor, and temperature of prehydrolysis, 81-100% of the hemicellulose, 3-32% of the glucans, and up to 46% of the Klason lignin could be solubilized. The lignocellulosic substrate produced from the pretreatment is readily converted to ethanol at a yield of approximately 91% of theoretical, with ethanol concentrations of up to 4.0 wt% in 55 h via a simultaneous saccharification and fermentation (SSF) process. In terms of xylose recovery and ethanol production level and rate, the present results are far superior to those previously reported using a single-temperature, dilute-acid pretreatment. 42 refs., 6 figs., 2 tabs.

  2. Material balance studies with continuous SSF for ethanol production using dilute-acid pretreated hybrid popular

    SciTech Connect

    Kadam, K.L.; Hayward, T.K.; Philippidis, G.P.

    1995-10-01

    Simultaneous saccharification and fermentation (SSF) is a leading process option for converting lignocellulosic biomass to ethanol. Economic industrial production of ethanol by SSF would likely require a continuous mode of operation, and development of a database on continuous SSF using industrial substrates is essential. To this end, a single-stage continuous SSF system was designed and used for studying ethanol production by Saccharomyces cerevisiae strain D{sub 5}A with dilute-acid preheated hybrid poplar as substrate. Material balance studies were conducted using the bench-scale system; the objectives of these studies were to gain insight into how the cells allocate carbon and to account for all the substrate flowing through the system. It was possible to close the total mass and carbon balances with {+-}3% accuracy, which is within the limits of experimental error. In a typical continuous SSF run, about 57% of the consumed carbon was used to produce ethanol and less than 1% to synthesize cell mass; thus the majority of carbon flow was to ethanol. The ethanol yields based on consumed substrate and volumetric productivities were in the range of 85% and 0.2 g ethanol/l{times}h, respectively; both values are within the expectations for a nearterm biomass-to-ethanol process. In the single-stage system used, continuous inoculation was not needed even for whole-slurry fermentations; this has significant economic implications since the inoculum cost can be significant.

  3. Pretreatment of Agave americana stalk for enzymatic saccharification.

    PubMed

    Yang, Qiang; Pan, Xuejun

    2012-12-01

    Agave americana is one of commonly grown agave species but currently less valuable because its large flower stalk cannot be used for producing alcoholic beverage. In the present study, the stalk was pretreated with dilute acid (DA), sulfite (SPORL), and sodium hydroxide (NaOH) to preliminarily assess its potential as feedstock for bioethanol production. The changes of cell wall components during the pretreatments, enzymatic digestibility of the pretreated stalks, and the adsorption of cellulases on the substrates were investigated. Results indicated that the pretreatments significantly improved the enzymatic digestibility of the agave stalk. SPORL pretreatment gave higher substrate and sugar yields, while NaOH pretreated stalk had better digestibility under the investigated conditions. The better hydrolysability of NaOH-pretreated stalk was attributed to low lignin and hemicellulose content and high affinity to cellulases. PMID:23122484

  4. Alkaline hydrogen peroxide pretreatment of softwood: hemicellulose degradation pathways.

    PubMed

    Alvarez-Vasco, Carlos; Zhang, Xiao

    2013-12-01

    This study investigated softwood hemicelluloses degradation pathways during alkaline hydrogen peroxide (AHP) pretreatment of Douglas fir. It was found that glucomannan is much more susceptible to alkaline pretreatment than xylan. Organic acids, including lactic, succinic, glycolic and formic acid are the predominant products from glucomannan degradation. At low treatment temperature (90°C), a small amount of formic acid is produced from glucomannan, whereas glucomannan degradation to lactic acid and succinic acid becomes the main reactions at 140°C and 180°C. The addition of H2O2 during alkaline pretreatment of D. fir led to a significant removal of lignin, which subsequently facilitated glucomannan solubilization. However, H2O2 has little direct effect on the glucomannan degradation reaction. The main degradation pathways involved in glucomannan conversion to organics acids are elucidated. The results from this study demonstrate the potential to optimize pretreatment conditions to maximize the value of biomass hemicellulose. PMID:24185034

  5. Enhancing bio-butanol production from biomass of Chlorella vulgaris JSC-6 with sequential alkali pretreatment and acid hydrolysis.

    PubMed

    Wang, Yue; Guo, Wanqian; Cheng, Chieh-Lun; Ho, Shih-Hsin; Chang, Jo-Shu; Ren, Nanqi

    2016-01-01

    This study presents a successful butanol production method using alkali and acid pretreated biomass of Chlorella vulgaris JSC-6. The butanol concentration, yield, and productivity were 13.1g/L, 0.58mol/mol sugar, 0.66g/L/h, respectively. Nearly 2.93L/L of biohydrogen was produced during the acidogenesis phase in ABE fermentation. The hydrogen yield and productivity were 0.39mol/mol sugar and 104.2g/L/h respectively. In addition, the high glucose consumption efficiency (97.5%) suggests that the hydrolysate pretreated with NaOH (1%) followed by H2SO4 (3%) did not contain inhibitors to the fermentation. It was also discovered that an excess amount of nitrogen sources arising from hydrolysis of highly concentrated microalgal biomass negatively affected the butanol production. This work demonstrates the technical feasibility of producing butanol from sustainable third-generation feedstock (i.e., microalgal biomass). PMID:26528906

  6. Conversion of distiller's grain into fuel alcohol and a higher-value animal feed by dilute-acid pretreatment.

    PubMed

    Tucker, Melvin P; Nagle, Nicholas J; Jennings, Edward W; Ibsen, Kelly N; Aden, Andy; Nguyen, Quang A; Kim, Kyoung H; Noll, Sally L

    2004-01-01

    Over the past three decades ethanol production in the United States has increased more than 10-fold, to approx 2.9 billion gal/yr (mid-2003), with ethanol production expected to reach 5 billion gal/yr by 2005. The simultaneous coproduction of 7 million t/yr of distiller's grain (DG) may potentially drive down the price of DG as a cattle feed supplement. The sale of residual DG for animal feed is an important part of corn dry-grind ethanol production economics; therefore, dry-grind ethanol producers are seeking ways to improve the quality of DG to increase market penetration and help stabilize prices. One possible improvement is to increase the protein content of DG by converting the residual starch and fiber into ethanol. We have developed methods for steam explosion, SO2, and dilute-sulfuric acid pretreatment of DG for evaluation as a feedstock for ethanol production. The highest soluble sugar yields (approximately 77% of available carbohydrate) were obtained by pretreatment of DG at 140 degrees C for 20 min with 3.27 wt% H2SO4. Fermentation protocols for pretreated DG were developed at the bench scale and scaled to a working volume of 809 L for production of hydrolyzed distiller's grain (HDG) for feeding trials. The pretreated DG was fermented with Saccharomyces cerevisiae D5A, with ethanol yields of 73% of theoretical from available glucans. The HDG was air-dried and used for turkey-feeding trials. The inclusion of HDG into turkey poult (as a model non-ruminant animal) diets at 5 and 10% levels, replacing corn and soybean meal, showed weight gains in the birds similar to controls, whereas 15 and 20% inclusion levels showed slight decreases (-6%) in weight gain. At the conclusion of the trial, no negative effects on internal organs or morphology, and no mortality among the poults, was found. The high protein levels (58-61%) available in HDG show promising economics for incorporation of this process into corn dry-grind ethanol plants. PMID:15054259

  7. Pretreatment methods for bioethanol production.

    PubMed

    Xu, Zhaoyang; Huang, Fang

    2014-09-01

    Lignocellulosic biomass, such as wood, grass, agricultural, and forest residues, are potential resources for the production of bioethanol. The current biochemical process of converting biomass to bioethanol typically consists of three main steps: pretreatment, enzymatic hydrolysis, and fermentation. For this process, pretreatment is probably the most crucial step since it has a large impact on the efficiency of the overall bioconversion. The aim of pretreatment is to disrupt recalcitrant structures of cellulosic biomass to make cellulose more accessible to the enzymes that convert carbohydrate polymers into fermentable sugars. This paper reviews several leading acidic, neutral, and alkaline pretreatments technologies. Different pretreatment methods, including dilute acid pretreatment (DAP), steam explosion pretreatment (SEP), organosolv, liquid hot water (LHW), ammonia fiber expansion (AFEX), soaking in aqueous ammonia (SAA), sodium hydroxide/lime pretreatments, and ozonolysis are intensively introduced and discussed. In this minireview, the key points are focused on the structural changes primarily in cellulose, hemicellulose, and lignin during the above leading pretreatment technologies. PMID:24972651

  8. Effect of reduced sulfur compounds on the fermentation of phosphoric acid pretreated sugarcane bagasse by ethanologenic Escherichia coli.

    PubMed

    Nieves, I U; Geddes, C C; Miller, E N; Mullinnix, M T; Hoffman, R W; Fu, Z; Tong, Z; Ingram, L O

    2011-04-01

    The addition of reduced sulfur compounds (thiosulfate, cysteine, sodium hydrosulfite, and sodium metabisulfite) increased growth and fermentation of dilute acid hydrolysate of sugarcane bagasse by ethanologenic Escherichia coli (strains LY180, EMFR9, and MM160). With sodium metabisulfite (0.5mM), toxicity was sufficiently reduced that slurries of pretreated biomass (10% dry weight including fiber and solubles) could be fermented by E. coli strain MM160 without solid-liquid separation or cleanup of sugars. A 6-h liquefaction step was added to improve mixing. Sodium metabisulfite also caused spectral changes at wavelengths corresponding to furfural and soluble products from lignin. Glucose and cellobiose were rapidly metabolized. Xylose utilization was improved by sodium metabisulfite but remained incomplete after 144 h. The overall ethanol yield for this liquefaction plus simultaneous saccharification and co-fermentation process was 0.20 g ethanol/g bagasse dry weight, 250 L/tonne (61 gal/US ton). PMID:21353535

  9. Cellulosic bioethanol production from Jerusalem artichoke (Helianthus tuberosus L.) using hydrogen peroxide-acetic acid (HPAC) pretreatment.

    PubMed

    Song, Younho; Wi, Seung Gon; Kim, Ho Myeong; Bae, Hyeun-Jong

    2016-08-01

    Jerusalem artichoke (JA) is recognized as a suitable candidate biomass crop for bioethanol production because it has a rapid growth rate and high biomass productivity. In this study, hydrogen peroxide-acetic acid (HPAC) pretreatment was used to enhance the enzymatic hydrolysis and to effectively remove the lignin of JA. With optimized enzyme doses, synergy was observed from the combination of three different enzymes (RUT-C30, pectinase, and xylanase) which provided a conversion rate was approximately 30% higher than the rate with from treatment with RUT-C30 alone. Fermentation of the JA hydrolyzates by Saccharomyces cerevisiae produced a fermentation yield of approximately 84%. Therefore, Jerusalem artichoke has potential as a bioenergy crop for bioethanol production. PMID:27115748

  10. Comparison of different mechanical refining technologies on the enzymatic digestibility of low severity acid pretreated corn stover.

    PubMed

    Chen, Xiaowen; Kuhn, Erik; Wang, Wei; Park, Sunkyu; Flanegan, Keith; Trass, Olev; Tenlep, Lisette; Tao, Ling; Tucker, Melvin

    2013-11-01

    The effect of mechanical refining on the enzymatic digestibility of pretreated corn stover (PCS) was investigated. Low severity, dilute sulfuric acid PCS was subjected to mechanical refining using a bench-scale food processor blender, a PFI mill, a 12-inch laboratory disk refiner, and a 25 mm co-rotating twin-screw extruder. Glucose yields from enzymatic hydrolysis were improved by 10-15% after blending and disk refining, while PFI refining and twin-screw extrusion showed a glucose yield improvement of 16-20%. A pilot scale refining test using a Szego mill was performed and showed approximately 10% improvements in biomass digestibility. This suggests the possibility to scale up a mechanical refining technique to obtain similar enzymatic digestibility glucose yield enhancement as achieved by PFI milling and extrusion technologies. Proposed mechanisms of each mechanical refining technology are presented and reasons for improvements in biomass digestibility are discussed in this paper. PMID:24001565

  11. Reductive leaching of manganese from low-grade pyrolusite ore in sulfuric acid using pyrolysis-pretreated sawdust as a reductant

    NASA Astrophysics Data System (ADS)

    Feng, Ya-li; Zhang, Shi-yuan; Li, Hao-ran

    2016-03-01

    Manganese (Mn) leaching and recovery from low-grade pyrolusite ore were studied using sulfuric acid (H2SO4) as a leachant and pyrolysis-pretreated sawdust as a reductant. The effects of the dosage of pyrolysis-pretreated sawdust to pyrolusite ore, the concentration of sulfuric acid, the liquid/solid ratio, the leaching temperature, and the leaching time on manganese and iron leaching efficiencies were investigated. Analysis of manganese and iron leaching efficiencies revealed that a high manganese leaching efficiency was achieved with low iron extraction. The optimal leaching efficiency was determined to be 20wt% pyrolysis-pretreated sawdust and 3.0 mol/L H2SO4 using a liquid/ solid ratio of 6.0 mL/g for 90 min at 90°C. Other low-grade pyrolusite ores were tested, and the results showed that they responded well with manganese leaching efficiencies greater than 98%.

  12. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain.

    PubMed

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  13. Lactic Acid Production from Pretreated Hydrolysates of Corn Stover by a Newly Developed Bacillus coagulans Strain

    PubMed Central

    Jiang, Ting; Qiao, Hui; Zheng, Zhaojuan; Chu, Qiulu; Li, Xin; Yong, Qiang; Ouyang, Jia

    2016-01-01

    An inhibitor-tolerance strain, Bacillus coagulans GKN316, was developed through atmospheric and room temperature plasma (ARTP) mutation and evolution experiment in condensed dilute-acid hydrolysate (CDH) of corn stover. The fermentabilities of other hydrolysates with B. coagulans GKN316 and the parental strain B. coagulans NL01 were assessed. When using condensed acid-catalyzed steam-exploded hydrolysate (CASEH), condensed acid-catalyzed liquid hot water hydrolysate (CALH) and condensed acid-catalyzed sulfite hydrolysate (CASH) as substrates, the concentration of lactic acid reached 45.39, 16.83, and 18.71 g/L by B. coagulans GKN316, respectively. But for B. coagulans NL01, only CASEH could be directly fermented to produce 15.47 g/L lactic acid. The individual inhibitory effect of furfural, 5-hydroxymethylfurfural (HMF), vanillin, syringaldehyde and p-hydroxybenzaldehyde (pHBal) on xylose utilization by B. coagulans GKN316 was also studied. The strain B. coagulans GKN316 could effectively convert these toxic inhibitors to the less toxic corresponding alcohols in situ. These results suggested that B. coagulans GKN316 was well suited to production of lactic acid from undetoxified lignocellulosic hydrolysates. PMID:26863012

  14. Improved ethanol yield and reduced Minimum Ethanol Selling Price (MESP) by modifying low severity dilute acid pretreatment with deacetylation and mechanical refining: 1) Experimental

    PubMed Central

    2012-01-01

    Background Historically, acid pretreatment technology for the production of bio-ethanol from corn stover has required severe conditions to overcome biomass recalcitrance. However, the high usage of acid and steam at severe pretreatment conditions hinders the economic feasibility of the ethanol production from biomass. In addition, the amount of acetate and furfural produced during harsh pretreatment is in the range that strongly inhibits cell growth and impedes ethanol fermentation. The current work addresses these issues through pretreatment with lower acid concentrations and temperatures incorporated with deacetylation and mechanical refining. Results The results showed that deacetylation with 0.1 M NaOH before acid pretreatment improved the monomeric xylose yield in pretreatment by up to 20% while keeping the furfural yield under 2%. Deacetylation also improved the glucose yield by 10% and the xylose yield by 20% during low solids enzymatic hydrolysis. Mechanical refining using a PFI mill further improved sugar yields during both low- and high-solids enzymatic hydrolysis. Mechanical refining also allowed enzyme loadings to be reduced while maintaining high yields. Deacetylation and mechanical refining are shown to assist in achieving 90% cellulose yield in high-solids (20%) enzymatic hydrolysis. When fermentations were performed under pH control to evaluate the effect of deacetylation and mechanical refining on the ethanol yields, glucose and xylose utilizations over 90% and ethanol yields over 90% were achieved. Overall ethanol yields were calculated based on experimental results for the base case and modified cases. One modified case that integrated deacetylation, mechanical refining, and washing was estimated to produce 88 gallons of ethanol per ton of biomass. Conclusion The current work developed a novel bio-ethanol process that features pretreatment with lower acid concentrations and temperatures incorporated with deacetylation and mechanical refining. The

  15. Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown

    PubMed Central

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Batstone, Damien; Yuan, Zhiguo

    2015-01-01

    This study presents a novel pre-treatment strategy using combined free nitrous acid (FNA i.e. HNO2) and hydrogen peroxide (H2O2) to enhance methane production from WAS, with the mechanisms investigated bio-molecularly. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10–80 mg/g TS), and their combinations followed by biochemical methane potential tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59–83%, compared to 13–23% and 56% with H2O2 pre-treatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with up to 163% increase in rapidly biodegradable fraction with combined pre-treatment. The molecular weight distribution and chemical structure analyses revealed the breakdown of soluble macromolecules with the combined pre-treatment caused by the deamination and oxidation of the typical functional groups in proteins, polysaccharides and phosphodiesters. These changes likely improved the biodegradability of WAS. PMID:26565653

  16. Combined free nitrous acid and hydrogen peroxide pre-treatment of waste activated sludge enhances methane production via organic molecule breakdown

    NASA Astrophysics Data System (ADS)

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Batstone, Damien; Yuan, Zhiguo

    2015-11-01

    This study presents a novel pre-treatment strategy using combined free nitrous acid (FNA i.e. HNO2) and hydrogen peroxide (H2O2) to enhance methane production from WAS, with the mechanisms investigated bio-molecularly. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10-80 mg/g TS), and their combinations followed by biochemical methane potential tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59-83%, compared to 13-23% and 56% with H2O2 pre-treatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with up to 163% increase in rapidly biodegradable fraction with combined pre-treatment. The molecular weight distribution and chemical structure analyses revealed the breakdown of soluble macromolecules with the combined pre-treatment caused by the deamination and oxidation of the typical functional groups in proteins, polysaccharides and phosphodiesters. These changes likely improved the biodegradability of WAS.

  17. Evaluation of ultrasonic, acid, thermo-alkaline and enzymatic pre-treatments on anaerobic digestion of Ulva rigida for biogas production.

    PubMed

    Karray, Raida; Hamza, Manel; Sayadi, Sami

    2015-01-01

    Pre-treatment of macroalgae has received considerable research globally due to its influence on the technical, economic and environmental sustainability of algae biogas production. Some of the most promising pre-treatment methods require the application of chemicals, enzymatic, and mechanical. This study focused on these pre-treatments of Ulva rigida for biogas production. The evaluation of different pre-treatment in terms of reducing sugar yields demonstrates that 3.62, 2.88, 2.53 and 7.3g/L of reducing sugar was obtained in acid catalysis, thermoalkaline, ultrasonication and enzymatic pre-treatment, respectively. However in crude macroalgae only 0.6g/L of reducing sugar was given. After anaerobic digestion, the enzymatic hydrolysis was demonstrated the best biogas yield than other pre-treatment which reached 626.5mL/gCODint with 62.65% of biodegradability. The best demonstrated method which uses crude broth of Aspergillus niger showed an effective and environmentally friendly strategy for enhancing the biogas production yields after the anaerobic digestion. PMID:25855526

  18. Production of fermentable sugars from corn fiber using soaking in aqueous ammonia (saa) pretreatment and fermentation to succinic acid by Escherichia coli afp184

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of corn fiber (CF), a by-product from the corn-to-ethanol conversion process, into fermentable sugar and succinic acid was investigated using soaking in aqueous ammonia (SAA) pretreatment followed by biological conversions including enzymatic hydrolysis and fermentation using genetically ...

  19. Significantly improving enzymatic saccharification of high crystallinity index's corn stover by combining ionic liquid [Bmim]Cl-HCl-water media with dilute NaOH pretreatment.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Zhu, Zheng-Zhong; Ding, Yun; Wang, Cheng; Xue, Yu-Feng; Rui, Huan; Tao, Zhi-Cheng; Zhang, Dan-Ping; Ma, Cui-Luan

    2015-01-01

    In this study, a pretreatment by combining acidified aqueous ionic liquid 1-butyl-3-methylimidazolium chloride (IL [Bmim]Cl) solution with dilute NaOH extraction was employed to pretreat high crystallinity index (CrI) of corn stover before its enzymatic saccharification. After NaOH extraction, [Bmim]Cl-HCl-water (78.8:1.2:20, w/w/w) media was used for further pretreatment at 130 °C for 30 min. After being enzymatically hydrolyzed for 48 h, corn stover pretreated could be biotransformed into reducing sugars in the yield of 95.1%. Furthermore, SEM, XRD and FTIR analyses of untreated and pretreated corn stovers were examined. It was found that the intact structure was disrupted by combination pretreatment and resulted in a porous and amorphous regenerated cellulosic material that greatly improved enzymatic hydrolysis. Finally, the recovered hydrolyzates obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. In conclusion, the combination pretreatment shows high potential application in future. PMID:25921785

  20. Effect of mechanical disruption on the effectiveness of three reactors used for dilute acid pretreatment of corn stover Part 2: morphological and structural substrate analysis

    PubMed Central

    2014-01-01

    Background Lignocellulosic biomass is a renewable, naturally mass-produced form of stored solar energy. Thermochemical pretreatment processes have been developed to address the challenge of biomass recalcitrance, however the optimization, cost reduction, and scalability of these processes remain as obstacles to the adoption of biofuel production processes at the industrial scale. In this study, we demonstrate that the type of reactor in which pretreatment is carried out can profoundly alter the micro- and nanostructure of the pretreated materials and dramatically affect the subsequent efficiency, and thus cost, of enzymatic conversion of cellulose. Results Multi-scale microscopy and quantitative image analysis was used to investigate the impact of different biomass pretreatment reactor configurations on plant cell wall structure. We identify correlations between enzymatic digestibility and geometric descriptors derived from the image data. Corn stover feedstock was pretreated under the same nominal conditions for dilute acid pretreatment (2.0 wt% H2SO4, 160°C, 5 min) using three representative types of reactors: ZipperClave® (ZC), steam gun (SG), and horizontal screw (HS) reactors. After 96 h of enzymatic digestion, biomass treated in the SG and HS reactors achieved much higher cellulose conversions, 88% and 95%, respectively, compared to the conversion obtained using the ZC reactor (68%). Imaging at the micro- and nanoscales revealed that the superior performance of the SG and HS reactors could be explained by reduced particle size, cellular dislocation, increased surface roughness, delamination, and nanofibrillation generated within the biomass particles during pretreatment. Conclusions Increased cellular dislocation, surface roughness, delamination, and nanofibrillation revealed by direct observation of the micro- and nanoscale change in accessibility explains the superior performance of reactors that augment pretreatment with physical energy. PMID:24690534

  1. Improving the enzymatic hydrolysis of dilute acid pretreated wheat straw by metal ion blocking of non-productive cellulase adsorption on lignin.

    PubMed

    Akimkulova, Ardak; Zhou, Yan; Zhao, Xuebing; Liu, Dehua

    2016-05-01

    Eleven salts were selected to screen the possible metal ions for blocking the non-productive adsorption of cellulase onto the lignin of dilute acid pretreated wheat straw. Mg(2+) was screened finally as the promising candidate. The optimal concentration of MgCl2 was 1mM, but the beneficial action was also dependent on pH, hydrolysis time and cellulase loading. Significant improvement of glucan conversion (19.3%) was observed at low cellulase loading (5FPU/g solid). Addition of isolated lignins, tannic acid and lignin model compounds to pure cellulose hydrolysis demonstrated that phenolic hydroxyl group (Ph-OH) was the main active site blocked by Mg(2+). The interaction between Mg(2+) and Ph-OH of lignin monomeric moieties followed an order of p-hydroxyphenyl (H)>guaiacyl (G)>syringyl (S). Mg(2+) blocking made the lignin surface less negatively charged, which might weaken the hydrogen bonding and electrostatically attractive interaction between lignin and cellulase enzymes. PMID:26930032

  2. Saccharification and Fermentation of Dilute-Acid-Pretreated Freeze-Dried Switchgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioethanol production potential of three oven-dried switchgrass germplasms (St6-1, St6-3 3E and St6-3F) containing 26.65 to 29.28% glucan, 17.92 to 19.37% xylan, and 17.74 to 19.23% lignin (dry matter basis) was investigated. Evaluation of the effect of three acid concentrations (0.5, 1.0 and 1.5% w...

  3. Dilute Acid Pretreatment of Oven-dried Switchgrass Germplasms for Bioethanol Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioethanol production potential of three oven-dried switchgrass germplasms (St6-1, St6- 3E and St6-3F) containing 26.65 to 29.28% glucan, 17.92 to 19.37% xylan, and 17.74 to 19.23% lignin (dry matter basis) was investigated. Evaluation of the effect of three acid concentrations (0.5, 1.0 and 1.5% w/...

  4. The rabbit pulmonary cytochrome P450 arachidonic acid metabolic pathway: characterization and significance.

    PubMed Central

    Zeldin, D C; Plitman, J D; Kobayashi, J; Miller, R F; Snapper, J R; Falck, J R; Szarek, J L; Philpot, R M; Capdevila, J H

    1995-01-01

    Cytochrome P450 metabolizes arachidonic acid to several unique and biologically active compounds in rabbit liver and kidney. Microsomal fractions prepared from rabbit lung homogenates metabolized arachidonic acid through cytochrome P450 pathways, yielding cis-epoxyeicosatrienoic acids (EETs) and their hydration products, vic-dihydroxyeicosatrienoic acids, mid-chain cis-trans conjugated dienols, and 19- and 20-hydroxyeicosatetraenoic acids. Inhibition studies using polyclonal antibodies prepared against purified CYP2B4 demonstrated 100% inhibition of arachidonic acid epoxide formation. Purified CYP2B4, reconstituted in the presence of NADPH-cytochrome P450 reductase and cytochrome b5, metabolized arachidonic acid, producing primarily EETs. EETs were detected in lung homogenate using gas chromatography/mass spectroscopy, providing evidence for the in vivo pulmonary cytochrome P450 epoxidation of arachidonic acid. Chiral analysis of these lung EETs demonstrated a preference for the 14(R),15(S)-, 11(S),12(R)-, and 8(S),9(R)-EET enantiomers. Both EETs and vic-dihydroxyeicosatrienoic acids were detected in bronchoalveolar lavage fluid. At micromolar concentrations, methylated 5,6-EET and 8,9-EET significantly relaxed histamine-contracted guinea pig hilar bronchi in vitro. In contrast, 20-hydroxyeicosatetraenoic acid caused contraction to near maximal tension. We conclude that CYP2B4, an abundant rabbit lung cytochrome P450 enzyme, is the primary constitutive pulmonary arachidonic acid epoxygenase and that these locally produced, biologically active eicosanoids may be involved in maintaining homeostasis within the lung. Images PMID:7738183

  5. Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis.

    PubMed

    Zeng, Jijiao; Tong, Zhaohui; Wang, Letian; Zhu, J Y; Ingram, Lonnie

    2014-02-01

    The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation chromatography (GPC), quantitative (13)C, and 2-D nuclear magnetic resonance (NMR). The structural analysis revealed that ethanol extractable lignin preserved basic lignin structure, but had relatively lower amount of β-O-4 linkages, syringyl/guaiacyl units ratio (S/G), p-coumarate/ferulate ratio, and other ending structures. The results also indicated that approximately 8% of mass weight was extracted by pure ethanol. The bagasse after ethanol extraction had an approximate 22% higher glucose yield after enzyme hydrolysis compared to pretreated bagasse without extraction. PMID:24412855

  6. Combination of high solids loading pretreatment and ethanol fermentation of whole slurry of pretreated rice straw to obtain high ethanol titers and yields.

    PubMed

    Jung, Young Hoon; Park, Hyun Min; Kim, Dong Hyun; Park, Yong-Cheol; Seo, Jin-Ho; Kim, Kyoung Heon

    2015-12-01

    In cellulosic ethanol production using lignocellulose, an increase in biomass solids loading during the pretreatment process significantly affects the final ethanol titer and the production cost. In this study, pretreatment using rice straw at high solids loading (20% (w/v)) was evaluated, using maleic acid as a catalyst. After pretreatment at optimal conditions of 190°C, 20 min, and 0.2% or 5% (w/v) maleic acid, the highest enzymatic digestibility obtained was over 80%. Simultaneous saccharification and fermentation (SSF) of the whole slurry of pretreated rice straw in the presence of activated carbon to separate inhibitory compounds generated a high ethanol yield of 62.8%, based on the initial glucan in unpretreated rice straw. These findings suggest that high solids loading pretreatment using maleic acid and SSF of the whole slurry of pretreated rice straw can be combined to improve the process economics of ethanol production. PMID:26461793

  7. Comparative Study of Corn Stover Pretreated by Dilute Acid and Cellulose Solvent-Based Lignocellulose Fractionation: Enzymatic Hydrolysis, Supramolecular Structure, and Substrate Accessibility

    SciTech Connect

    Zhu, Z.; Sathitsuksanoh, N.; Vinzant, T.; Schell, D. J.; McMillian, J. D.; Zhang, Y. H. P.

    2009-07-01

    Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.3 mg cellulase per gram of glucan], glucan digestibilities of the corn stover pretreated by DA and COSLIF were 84% at hour 72 and 97% at hour 24, respectively. At a low cellulase loading (5 FPUs per gram of glucan), digestibility remained as high as 93% at hour 24 for the COSLIF-pretreated corn stover but reached only {approx}60% for the DA-pretreated biomass. Quantitative determinations of total substrate accessibility to cellulase (TSAC), cellulose accessibility to cellulase (CAC), and non-cellulose accessibility to cellulase (NCAC) based on adsorption of a non-hydrolytic recombinant protein TGC were measured for the first time. The COSLIF-pretreated corn stover had a CAC of 11.57 m{sup 2}/g, nearly twice that of the DA-pretreated biomass (5.89 m{sup 2}/g). These results, along with scanning electron microscopy images showing dramatic structural differences between the DA- and COSLIF-pretreated samples, suggest that COSLIF treatment disrupts microfibrillar structures within biomass while DA treatment mainly removes hemicellulose. Under the tested conditions COSLIF treatment breaks down lignocellulose structure more extensively than DA treatment, producing a more enzymatically reactive material with a higher CAC accompanied by faster hydrolysis rates and higher enzymatic digestibility.

  8. Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

    PubMed

    Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

    2016-05-01

    Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed. PMID:26797927

  9. Simultaneous saccharification and co-fermentation of dry diluted acid pretreated corn stover at high dry matter loading: Overcoming the inhibitors by non-tolerant yeast.

    PubMed

    Zhu, Jia-Qing; Qin, Lei; Li, Wen-Chao; Zhang, Jian; Bao, Jie; Huang, Yao-Dong; Li, Bing-Zhi; Yuan, Ying-Jin

    2015-12-01

    Dry dilute acid pretreatment (DDAP) is a promising method for lignocellulose bioconversion, although inhibitors generated during the pretreatment impede the fermentation severely. We developed the simultaneous saccharification and co-fermentation (SScF) of DDAP pretreated biomass at high solid loading using xylose fermenting Saccharomyces cerevisiae, SyBE005. Effect of temperature on SScF showed that ethanol yield at 34°C was 10.2% higher than that at 38°C. Ethanol concentration reached 29.5 g/L at 15% (w/w) dry matter loading, while SScF almost ceased at the beginning at 25% (w/w) dry matter loading of DDAP pretreated corn stover. According to the effect of the diluted hydrolysate on the fermentation of strain SyBE005, a fed-batch mode was developed for the SScF of DDAP pretreated corn stover with 25% dry matter loading without detoxification, and 40.0 g/L ethanol was achieved. In addition, high yeast inoculation improved xylose utilization and the final ethanol concentration reached 47.2 g/L. PMID:26363500

  10. Improving a recombinant Zymomonas mobilis strain 8b through continuous adaptation on dilute acid pretreated corn stover hydrolysate

    DOE PAGESBeta

    Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui; Smith, Holly; Dowe, Nancy; Zhang, Min; Pienkos, Philip T.

    2015-03-31

    Complete conversion of the major sugars of biomass including both the C5 and C6 sugars is critical for biofuel production processes. Several inhibitory compounds like acetate, hydroxymethylfurfural (HMF), and furfural are produced from the biomass pretreatment process leading to ‘hydrolysate toxicity,’ a major problem for microorganisms to achieve complete sugar utilization. Therefore, development of more robust microorganisms to utilize the sugars released from biomass under toxic environment is critical. In this study, we use continuous culture methodologies to evolve and adapt the ethanologenic bacterium Zymomonas mobilis to improve its ethanol productivity using corn stover hydrolysate. The results are the following:more » A turbidostat was used to adapt the Z. mobilis strain 8b in the pretreated corn stover liquor. The adaptation was initiated using pure sugar (glucose and xylose) followed by feeding neutralized liquor at different dilution rates. Once the turbidostat reached 60% liquor content, the cells began washing out and the adaptation was stopped. Several ‘sub-strains’ were isolated, and one of them, SS3 (sub-strain 3), had 59% higher xylose utilization than the parent strain 8b when evaluated on 55% neutralized PCS (pretreated corn stover) liquor. Using saccharified PCS slurry generated by enzymatic hydrolysis from 25% solids loading, SS3 generated an ethanol yield of 75.5% compared to 64% for parent strain 8b. Furthermore, the total xylose utilization was 57.7% for SS3 versus 27.4% for strain 8b. To determine the underlying genotypes in these new sub-strains, we conducted genomic resequencing and identified numerous single-nucleotide mutations (SNPs) that had arisen in SS3. We further performed quantitative reverse transcription PCR (qRT-PCR) on genes potentially affected by these SNPs and identified significant down-regulation of two genes, ZMO0153 and ZMO0776, in SS3 suggesting potential genetic mechanisms behind SS3’s improved

  11. Lignin structural alterations in thermochemical pretreatments with limited delignification

    SciTech Connect

    Pu, Yunqiao; Hu, Fan; Huang, Fang; Ragauskas, Arthur J.

    2015-08-02

    Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion, and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.

  12. Lignin structural alterations in thermochemical pretreatments with limited delignification

    DOE PAGESBeta

    Pu, Yunqiao; Hu, Fan; Huang, Fang; Ragauskas, Arthur J.

    2015-08-02

    Lignocellulosic biomass has a complex and rigid cell wall structure that makes biomass recalcitrant to biological and chemical degradation. Among the three major structural biopolymers (i.e., cellulose, hemicellulose and lignin) in plant cell walls, lignin is considered the most recalcitrant component and generally plays a negative role in the biochemical conversion of biomass to biofuels. The conversion of biomass to biofuels through a biochemical platform usually requires a pretreatment stage to reduce the recalcitrance. Pretreatment renders compositional and structural changes of biomass with these changes ultimately govern the efficiency of the subsequent enzymatic hydrolysis. Dilute acid, hot water, steam explosion,more » and ammonia fiber expansion pretreatments are among the leading thermochemical pretreatments with a limited delignification that can reduce biomass recalcitrance. Practical applications of these pretreatment are rapidly developing as illustrated by recent commercial scale cellulosic ethanol plants. While these thermochemical pretreatments generally lead to only a limited delignification and no significant change of lignin content in the pretreated biomass, the lignin transformations that occur during these pretreatments and the roles they play in recalcitrance reduction is an important research aspect. This review highlights recent advances in our understanding of lignin alterations during these limited delignification thermochemical pretreatments, with emphasis on lignin chemical structures, molecular weights, and redistributions in the pretreated biomass.« less

  13. Protective effect of the combinations of glycyrrhizic, ferulic and cinnamic acid pretreatment on myocardial ischemia-reperfusion injury in rats

    PubMed Central

    GAO, YUQIN; HAO, JIPING; ZHANG, HONGKAO; QIAN, GUOQIANG; JIANG, RENWANG; HU, JING; WANG, JIANING; LEI, ZHANG; ZHAO, GUOPING

    2015-01-01

    The aim of this study was to find an effective drug cocktail pretreatment to protect myocardial tissue of the heart from ischemia-reperfusion (I/R) injury. The mechanisms underlying the effects of the drug cocktail were subsequently explored in order to expand the application of Dang-gui-si-ni-tang (DGSN), a Traditional Chinese Medicine. The active components of DGSN in the serum following oral administration were investigated using high-performance liquid chromatography. The activity of superoxide dismutase (SOD) and malondialdehyde (MDA) levels were then analyzed to show the effect of the active components in the treatment of myocardial I/R injury. An L16 (44) orthogonal experiment was utilized to determine the most effective cocktail mix and the mechanism underlying the effect of this mix on myocardial I/R injury was investigated. It was observed that FCG, a mixture of glycyrrhizic (50 mg/kg), cinnamic (200 mg/kg) and ferulic (300 mg/kg) acid, was the optimal drug cocktail present in DGSN. This was absorbed into the blood following oral administration and was shown to decrease MDA levels and increase the activity of SOD. In conclusion, the findings suggest that FCG, a combination of active ingredients in the DGSN decoction, can be absorbed into the blood and protect the myocardium from I/R injury. PMID:25574212

  14. GREET Pretreatment Module

    SciTech Connect

    Adom, Felix K.; Dunn, Jennifer B.; Han, Jeongwoo

    2014-09-01

    A wide range of biofuels and biochemicals can be produced from biomass via different pretreatment technologies that yield sugars. This report documents the material and energy flows that occur when fermentable sugars from four lignocellulosic feedstocks (corn stover, miscanthus, switchgrass, and poplar) are produced via dilute acid pretreatment and ammonia fiber expansion. These flows are documented for inclusion in the pretreatment module of the Greenhouses Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. Process simulations of each pretreatment technology were developed in Aspen Plus. Material and energy consumption data from Aspen Plus were then compiled in the GREET pretreatment module. The module estimates the cradle-to-gate fossil energy consumption (FEC) and greenhouse gas (GHG) emissions associated with producing fermentable sugars. This report documents the data and methodology used to develop this module and the cradle-to-gate FEC and GHG emissions that result from producing fermentable sugars.

  15. Feasibility of filamentous fungi for biofuel production using hydrolysate from dilute sulfuric acid pretreatment of wheat straw

    PubMed Central

    2012-01-01

    Background Lipids produced from filamentous fungi show great promise for biofuel production, but a major limiting factor is the high production cost attributed to feedstock. Lignocellulosic biomass is a suitable feedstock for biofuel production due to its abundance and low value. However, very limited study has been performed on lipid production by culturing oleaginous fungi with lignocellulosic materials. Thus, identification of filamentous fungal strains capable of utilizing lignocellulosic hydrolysates for lipid accumulation is critical to improve the process and reduce the production cost. Results The growth performances of eleven filamentous fungi were investigated when cultured on glucose and xylose. Their dry cell weights, lipid contents and fatty acid profiles were determined. Six fungal strains with high lipid contents were selected to culture with the hydrolysate from dilute sulfuric acid pretreatment of wheat straw. The results showed that all the selected fungal strains were able to grow on both detoxified liquid hydrolysate (DLH) and non-detoxified liquid hydrolysate (NDLH). The highest lipid content of 39.4% was obtained by Mortierella isabellina on NDLH. In addition, NDLH with some precipitate could help M. isabellina form pellets with an average diameter of 0.11 mm. Conclusion This study demonstrated the possibility of fungal lipid production from lignocellulosic biomass. M. isabellina was the best lipid producer grown on lignocellulosic hydrolysates among the tested filamentous fungi, because it could not only accumulate oils with a high content by directly utilizing NDLH to simplify the fermentation process, but also form proper pellets to benefit the downstream harvesting. Considering the yield and cost, fungal lipids from lignocellulosic biomass are promising alternative sources for biodiesel production. PMID:22824058

  16. Ethanol production from rice hull using Pichia stipitis and optimization of acid pretreatment and detoxification processes.

    PubMed

    Germec, Mustafa; Kartal, Fatma Kubra; Bilgic, Merve; Ilgin, Merve; Ilhan, Eda; Güldali, Hazal; Isci, Aslı; Turhan, Irfan

    2016-07-01

    The goal of this study was to produce ethanol from rice hull hydrolysates (RHHs) using Pichia stipitis strains and to optimize dilute acid hydrolysis and detoxification processes by response surface methodology (RSM). The optimized conditions were found as 127.14°C, solid:liquid ratio of 1:10.44 (w/v), acid ratio of 2.52% (w/v), and hydrolysis time of 22.01 min. At these conditions, the fermentable sugar concentration was 21.87 g/L. Additionally, the nondetoxified RHH at optimized conditions contained 865.2 mg/L phenolics, 24.06 g/L fermentable sugar, no hydroxymethylfurfural (HMF), 1.62 g/L acetate, 0.36 g/L lactate, 1.89 g/L glucose, and 13.49 g/L fructose + xylose. Furthermore, RHH was detoxified with various methods and the best procedures were found to be neutralization with CaO or charcoal treatment in terms of the reduction of inhibitory compounds as compared to nondetoxified RHH. After detoxification procedures, the content of hydrolysates consisted of 557.2 and 203.1 mg/L phenolics, 19.7 and 21.60 g/L fermentable sugar, no HMF, 0.98 and 1.39 g/L acetate, 0 and 0.04 g/L lactate, 1.13 and 1.03 g/L glucose, and 8.46 and 12.09 g/L fructose + xylose, respectively. Moreover, the base-line mediums (control), and nondetoxified and detoxified hydrolysates were used to produce ethanol by using P. stipitis strains. The highest yields except that of base-line mediums were achieved using neutralization (35.69 and 38.33% by P. stipitis ATCC 58784 and ATCC 58785, respectively) and charcoal (37.55% by P. stipitis ATCC 58785) detoxification methods. Results showed that the rice hull can be utilized as a good feedstock for ethanol production using P. stipitis. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:872-882, 2016. PMID:27071671

  17. Acid-Catalyzed Algal Biomass Pretreatment for Integrated Lipid and Carbohydrate-Based Biofuels Production

    SciTech Connect

    Laurens, L. M. L.; Nagle, N.; Davis, R.; Sweeney, N.; Van Wychen, S.; Lowell, A.; Pienkos, P. T.

    2014-11-12

    One of the major challenges associated with algal biofuels production in a biorefinery-type setting is improving biomass utilization in its entirety, increasing the process energetic yields and providing economically viable and scalable co-product concepts. We demonstrate the effectiveness of a novel, integrated technology based on moderate temperatures and low pH to convert the carbohydrates in wet algal biomass to soluble sugars for fermentation, while making lipids more accessible for downstream extraction and leaving a protein-enriched fraction behind. We studied the effect of harvest timing on the conversion yields, using two algal strains; Chlorella and Scenedesmus, generating biomass with distinctive compositional ratios of protein, carbohydrate, and lipids. We found that the late harvest Scenedesmus biomass had the maximum theoretical biofuel potential at 143 gasoline gallon equivalent (GGE) combined fuel yield per dry ton biomass, followed by late harvest Chlorella at 128 GGE per ton. Our experimental data show a clear difference between the two strains, as Scenedesmus was more successfully converted in this process with a demonstrated 97 GGE per ton. Our measurements indicated a release of >90% of the available glucose in the hydrolysate liquors and an extraction and recovery of up to 97% of the fatty acids from wet biomass. Techno-economic analysis for the combined product yields indicates that this process exhibits the potential to improve per-gallon fuel costs by up to 33% compared to a lipids-only process for one strain, Scenedesmus, grown to the mid-point harvest condition.

  18. Biomass pretreatment

    SciTech Connect

    Hennessey, Susan Marie; Friend, Julie; Elander, Richard T; Tucker, III, Melvin P

    2013-05-21

    A method is provided for producing an improved pretreated biomass product for use in saccharification followed by fermentation to produce a target chemical that includes removal of saccharification and or fermentation inhibitors from the pretreated biomass product. Specifically, the pretreated biomass product derived from using the present method has fewer inhibitors of saccharification and/or fermentation without a loss in sugar content.

  19. Acid-Catalyzed Algal Biomass Pretreatment for Integrated Lipid and Carbohydrate-Based Biofuels Production

    DOE PAGESBeta

    Laurens, L. M. L.; Nagle, N.; Davis, R.; Sweeney, N.; Van Wychen, S.; Lowell, A.; Pienkos, P. T.

    2014-11-12

    One of the major challenges associated with algal biofuels production in a biorefinery-type setting is improving biomass utilization in its entirety, increasing the process energetic yields and providing economically viable and scalable co-product concepts. We demonstrate the effectiveness of a novel, integrated technology based on moderate temperatures and low pH to convert the carbohydrates in wet algal biomass to soluble sugars for fermentation, while making lipids more accessible for downstream extraction and leaving a protein-enriched fraction behind. We studied the effect of harvest timing on the conversion yields, using two algal strains; Chlorella and Scenedesmus, generating biomass with distinctive compositionalmore » ratios of protein, carbohydrate, and lipids. We found that the late harvest Scenedesmus biomass had the maximum theoretical biofuel potential at 143 gasoline gallon equivalent (GGE) combined fuel yield per dry ton biomass, followed by late harvest Chlorella at 128 GGE per ton. Our experimental data show a clear difference between the two strains, as Scenedesmus was more successfully converted in this process with a demonstrated 97 GGE per ton. Our measurements indicated a release of >90% of the available glucose in the hydrolysate liquors and an extraction and recovery of up to 97% of the fatty acids from wet biomass. Techno-economic analysis for the combined product yields indicates that this process exhibits the potential to improve per-gallon fuel costs by up to 33% compared to a lipids-only process for one strain, Scenedesmus, grown to the mid-point harvest condition.« less

  20. Organic acids pretreatment effect on Rosa bourbonia phyto-biomass for removal of Pb(II) and Cu(II) from aqueous media.

    PubMed

    Manzoor, Qaisar; Nadeem, Raziya; Iqbal, Munawar; Saeed, Rashid; Ansari, Tariq M

    2013-03-01

    The sorption of Pb(II) and Cu(II) form aqueous media by Rosa bourbonia waste phyto-biomass (RBWPB) pretreated with organic acids was investigated as a function of biosorbent dosage, initial metal ions concentration and contact time. The equilibrium biosorption data was analyzed using two kinetic models (pseudo-first order and pseudo-second order) and two isotherm models (Langmuir and Freundlich). The RBWPB was successfully applied for sequestration of both heavy metal ions; however, organic acids pretreatments decreased the metal adsorption capacity of RBWPB. The Langmuir model fitted well to the data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of Pb(II) and Cu(II) metal ions. Gibbs free energy indicated the spontaneous adsorption of Pb(II) and Cu(II) onto RBWPB. PMID:23433975

  1. Global transcriptome analysis of Clostridium thermocellum ATCC 27405 during growth on dilute acid pretreated Populus and switchgrass

    PubMed Central

    2013-01-01

    Background The thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. The aim of this study was to investigate C. thermocellum genes required to ferment biomass substrates and to conduct a robust comparison of DNA microarray and RNA sequencing (RNA-seq) analytical platforms. Results C. thermocellum ATCC 27405 fermentations were conducted with a 5 g/L solid substrate loading of either pretreated switchgrass or Populus. Quantitative saccharification and inductively coupled plasma emission spectroscopy (ICP-ES) for elemental analysis revealed composition differences between biomass substrates, which may have influenced growth and transcriptomic profiles. High quality RNA was prepared for C. thermocellum grown on solid substrates and transcriptome profiles were obtained for two time points during active growth (12 hours and 37 hours postinoculation). A comparison of two transcriptomic analytical techniques, microarray and RNA-seq, was performed and the data analyzed for statistical significance. Large expression differences for cellulosomal genes were not observed. We updated gene predictions for the strain and a small novel gene, Cthe_3383, with a putative AgrD peptide quorum sensing function was among the most highly expressed genes. RNA-seq data also supported different small regulatory RNA predictions over others. The DNA microarray gave a greater number (2,351) of significant genes relative to RNA-seq (280 genes when normalized by the kernel density mean of M component (KDMM) method) in an analysis of variance (ANOVA) testing method with a 5% false discovery rate (FDR). When a 2-fold difference in expression threshold was applied, 73 genes were significantly differentially expressed in common between the two techniques. Sulfate and phosphate uptake/utilization genes, along with genes for a putative efflux pump system were some of the most differentially regulated transcripts

  2. Global transcriptome analysis of Clostridium thermocellum ATCC 27405 during growth on dilute acid pretreated Populus and switchgrass

    SciTech Connect

    Wilson, Charlotte M; Rodriguez Jr, Miguel; Johnson, Courtney M; Martin, S L.; Chu, Tzu Ming; Wolfinger, Russ; Hauser, Loren John; Land, Miriam L; Klingeman, Dawn Marie; Tschaplinski, Timothy J; Mielenz, Jonathan R; Brown, Steven D

    2013-01-01

    Background The thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. The aim of this study was to investigate C. thermocellum genes required to ferment biomass substrates and to conduct a robust comparison of DNA microarray and RNA sequencing (RNA-seq) analytical platforms. Results C. thermocellum ATCC 27405 fermentations were conducted with a 5 g/L solid substrate loading of either pretreated switchgrass or Populus. Quantitative saccharification and inductively coupled plasma emission spectroscopy (ICP-ES) for elemental analysis revealed composition differences between biomass substrates, which may have influenced growth and transcriptomic profiles. High quality RNA was prepared for C. thermocellum grown on solid substrates and transcriptome profiles were obtained for two time points during active growth (12 hours and 37 hours postinoculation). A comparison of two transcriptomic analytical techniques, microarray and RNA-seq, was performed and the data analyzed for statistical significance. Large expression differences for cellulosomal genes were not observed. We updated gene predictions for the strain and a small novel gene, Cthe_3383, with a putative AgrD peptide quorum sensing function was among the most highly expressed genes. RNAseq data also supported different small regulatory RNA predictions over others. The DNA microarray gave a greater number (2,351) of significant genes relative to RNA-seq (280 genes when normalized by the kernel density mean of M component (KDMM) method) in an analysis of variance (ANOVA) testing method with a 5 % false discovery rate (FDR). When a 2-fold difference in expression threshold was applied, 73 genes were significantly differentially expressed in common between the two techniques. Sulfate and phosphate uptake/utilization genes, along with genes for a putative efflux pump system were some of the most differentially regulated transcripts

  3. Sonophotocatalytic degradation of dye C.I. Acid Orange 7 by TiO2 and Ag nanoparticles immobilized on corona pretreated polypropylene non-woven fabric.

    PubMed

    Marković, Darka; Šaponjić, Zoran; Radoičić, Marija; Radetić, Tamara; Vodnik, Vesna; Potkonjak, Branislav; Radetić, Maja

    2015-05-01

    This study discusses the possibility of using corona pre-treated polypropylene (PP) non-woven fabric as a support for immobilization of colloidal TiO2 and Ag nanoparticles in order to remove dye C.I. Acid Orange 7 from aqueous solution. Dye removal efficiency by sonocatalysis, photocatalysis and sonophotocatalysis was evaluated on corona pre-treated fabric loaded with TiO2 nanoparticles, corona pre-treated fabric double loaded with TiO2 nanoparticles and corona pre-treated fabrics loaded with TiO2 nanoparticles before and after deposition of Ag nanoparticles. In addition, the stability of PP non-woven fabric during these processes was investigated. The substrates were characterized by SEM, EDX and AAS analyses. The change of the dye concentration was evaluated by UV-VIS spectrophotometry. Unlike sonocatalysis and photocatalysis, complete dye removal from both solution and non-woven fabric was obtained already after 240-270 min of sonophotocatalysis. Corona pre-treated PP non-woven fabric loaded with Ag nanoparticles prior to deposition of TiO2 nanoparticles provided excellent degradation efficiency and superior reusability. Sonophotocatalytic degradation of dye in the presence of all investigated samples was the most prominent in acidic conditions. Although this nanocomposite system ensured fast discoloration of dye solution, TOC values of water measured after sonophotocatalysis were not satisfactory because of PP degradation. Therefore, it is suggested to include TOC evaluation in each case study where different supports for TiO2 nanoparticles are used since these nanoparticles may guarantee the dye removal from solution but the stability of support could be problematic causing even more serious environmental impact. PMID:25487219

  4. Significant association between parathyroid hormone and uric acid level in men

    PubMed Central

    Chin, Kok-Yong; Ima Nirwana, Soelaiman; Wan Ngah, Wan Zurinah

    2015-01-01

    Background Previous reports of patients undergoing parathyroidectomy and of patients receiving teriparatide as antiosteoporotic treatment have suggested a plausible relationship between parathyroid hormone (PTH) and uric acid. However, similar data at population level were lacking. The current study aimed to determine the relationship between PTH and uric acid in a group of apparently healthy Malaysian men. Methods A cross-sectional study was conducted among 380 Malay and Chinese men aged 20 years and above, residing in the Klang Valley, Malaysia. Their body anthropometry was measured, and their fasting blood samples were collected for biochemical analysis. The relationship between PTH and uric acid was analyzed using regression analysis. Results Increased serum PTH level was significantly associated with increased serum uric acid level (β=0.165; P=0.001). Increased PTH level was also significantly associated with the condition of hyperuricemia in the study population (odds ratio [OR], 1.045; 95% confidence interval [CI], 1.017–1.075; P=0.002). All analyses were adjusted for age, body mass index, vitamin D, total calcium, inorganic phosphate, blood urea nitrogen and creatinine levels. Conclusion There is a significant positive relationship between PTH level and uric acid level in Malaysian men. This relationship and its clinical significance should be further investigated in a larger longitudinal study. PMID:26346636

  5. Sequential extrusion-microwave pretreatment of switchgrass and big bluestem.

    PubMed

    Karunanithy, C; Muthukumarappan, K; Gibbons, W R

    2014-02-01

    Developing an effective and economical biomass pretreatment method is a significant roadblock to meeting the ever growing demand for transportation fuels. Earlier studies with different feedstocks revealed that in the absence of chemicals, neither extrusion nor microwave could be standalone pretreatments. However, there is potential that the advantages of these individual methods can be harnessed in a sequential pretreatment process. Accordingly, switchgrass and big bluestem were extruded and then subject to microwave pretreatment, under optimal conditions that had been separately determined in prior studies. Pretreated biomass was then subject to enzymatic hydrolysis to understand the effectiveness of the sequential pretreatment on sugar recovery and generation of fermentation inhibitors. Statistical analysis confirmed that moisture content, microwave power level, and exposure time (and their interactions) had significant influence on sugar recovery. Sequential pretreatment of switchgrass (25% moisture, 450W and 2.5min) resulted in a maximum glucose, xylose, and total sugar recovery of 52.6%, 75.5%, and 59.2%, respectively. This was higher by 1.27 and 2.71, 1.21 and 4.60, and 1.25 and 2.87 times compared to extrusion alone and the unpretreated control, respectively. The same sequential pretreatment conditions achieved maximum glucose, xylose, and total sugar recovery of 83.2%, 92.1%, and 68.1%, respectively, for big bluestem. This was 1.14 and 4.1, 1.18 and 2.7, and 1.20 and 3.0 times higher than extrusion alone and the unpretreated control, respectively. This sequential pretreatment process did not aggravate acetic acid formation over levels observed with the individual pretreatments. Furthermore, furfural, HMF, and formic acid were not detected in any of the treatments. Although the sequential pretreatment process enhanced sugar recovery without increasing the levels of potential fermentation inhibitors, the increased energy input for the microwave treatment may

  6. Molecular mechanism and functional significance of acid generation in the Drosophila midgut

    PubMed Central

    Overend, Gayle; Luo, Yuan; Henderson, Louise; Douglas, Angela E.; Davies, Shireen A.; Dow, Julian A. T.

    2016-01-01

    The gut of Drosophila melanogaster includes a proximal acidic region (~pH 2), however the genome lacks the H+/K+ ATPase characteristic of the mammalian gastric parietal cell, and the molecular mechanisms of acid generation are poorly understood. Here, we show that maintenance of the low pH of the acidic region is dependent on H+ V-ATPase, together with carbonic anhydrase and five further transporters or channels that mediate K+, Cl− and HCO3− transport. Abrogation of the low pH did not influence larval survival under standard laboratory conditions, but was deleterious for insects subjected to high Na+ or K+ load. Insects with elevated pH in the acidic region displayed increased susceptibility to Pseudomonas pathogens and increased abundance of key members of the gut microbiota (Acetobacter and Lactobacillus), suggesting that the acidic region has bacteriostatic or bacteriocidal activity. Conversely, the pH of the acidic region was significantly reduced in germ-free Drosophila, indicative of a role of the gut bacteria in shaping the pH conditions of the gut. These results demonstrate that the acidic gut region protects the insect and gut microbiome from pathological disruption, and shed light on the mechanisms by which low pH can be maintained in the absence of H+, K+ ATPase. PMID:27250760

  7. Molecular mechanism and functional significance of acid generation in the Drosophila midgut.

    PubMed

    Overend, Gayle; Luo, Yuan; Henderson, Louise; Douglas, Angela E; Davies, Shireen A; Dow, Julian A T

    2016-01-01

    The gut of Drosophila melanogaster includes a proximal acidic region (~pH 2), however the genome lacks the H(+)/K(+) ATPase characteristic of the mammalian gastric parietal cell, and the molecular mechanisms of acid generation are poorly understood. Here, we show that maintenance of the low pH of the acidic region is dependent on H(+) V-ATPase, together with carbonic anhydrase and five further transporters or channels that mediate K(+), Cl(-) and HCO3(-) transport. Abrogation of the low pH did not influence larval survival under standard laboratory conditions, but was deleterious for insects subjected to high Na(+) or K(+) load. Insects with elevated pH in the acidic region displayed increased susceptibility to Pseudomonas pathogens and increased abundance of key members of the gut microbiota (Acetobacter and Lactobacillus), suggesting that the acidic region has bacteriostatic or bacteriocidal activity. Conversely, the pH of the acidic region was significantly reduced in germ-free Drosophila, indicative of a role of the gut bacteria in shaping the pH conditions of the gut. These results demonstrate that the acidic gut region protects the insect and gut microbiome from pathological disruption, and shed light on the mechanisms by which low pH can be maintained in the absence of H(+), K(+) ATPase. PMID:27250760

  8. Incorporation of flavonoid derivatives or pentagalloyl glucose into lignin enhances cell wall saccharification following mild alkaline or acidic pretreatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Partial substitution of normal monolignols with phenolic precursors from other metabolic pathways may improve the susceptibility of lignified biomass to chemical pretreatment and enzymatic saccharification for biofuel production. Flavonoids and gallate esters readily undergo oxidative coupling react...

  9. Pretreatment by low-dose fibrates protects against acute free fatty acid-induced renal tubule toxicity by counteracting PPAR{alpha} deterioration

    SciTech Connect

    Takahashi, Kyoko; Kamijo, Yuji; Hora, Kazuhiko; Hashimoto, Koji; Higuchi, Makoto; Nakajima, Takero; Ehara, Takashi; Shigematsu, Hidekazu; Gonzalez, Frank J.; Aoyama, Toshifumi

    2011-05-01

    Development of a preventive strategy against tubular damage associated with proteinuria is of great importance. Recently, free fatty acid (FFA) toxicities accompanying proteinuria were found to be a main cause of tubular damage, which was aggravated by insufficiency of peroxisome proliferator-activated receptor alpha (PPAR{alpha}), suggesting the benefit of PPAR{alpha} activation. However, an earlier study using a murine acute tubular injury model, FFA-overload nephropathy, demonstrated that high-dose treatment of PPAR{alpha} agonist (0.5% clofibrate diet) aggravated the tubular damage as a consequence of excess serum accumulation of clofibrate metabolites due to decreased kidney elimination. To induce the renoprotective effects of PPAR{alpha} agonists without drug accumulation, we tried a pretreatment study using low-dose clofibrate (0.1% clofibrate diet) using the same murine model. Low-dose clofibrate pretreatment prevented acute tubular injuries without accumulation of its metabolites. The tubular protective effects appeared to be associated with the counteraction of PPAR{alpha} deterioration, resulting in the decrease of FFAs influx to the kidney, maintenance of fatty acid oxidation, diminution of intracellular accumulation of undigested FFAs, and attenuation of disease developmental factors including oxidative stress, apoptosis, and NF{kappa}B activation. These effects are common to other fibrates and dependent on PPAR{alpha} function. Interestingly, however, clofibrate pretreatment also exerted PPAR{alpha}-independent tubular toxicities in PPAR{alpha}-null mice with FFA-overload nephropathy. The favorable properties of fibrates are evident when PPAR{alpha}-dependent tubular protective effects outweigh their PPAR{alpha}-independent tubular toxicities. This delicate balance seems to be easily affected by the drug dose. It will be important to establish the appropriate dosage of fibrates for treatment against kidney disease and to develop a novel PPAR

  10. Significance of long-chain polyunsaturated fatty acids (PUFAs) for the development and behaviour of children.

    PubMed

    Schuchardt, Jan Philipp; Huss, Michael; Stauss-Grabo, Manuela; Hahn, Andreas

    2010-02-01

    omega-6 and omega-3 polyunsaturated fatty acids (PUFAs) play a central role in the normal development and functioning of the brain and central nervous system. Long-chain PUFAs (LC-PUFAs) such as eicosapentaenoic acid (EPA, C20:5omega-3), docosahexaenoic acid (DHA, C22:6omega-3) and arachidonic acid (AA, C20:4omega-6), in particular, are involved in numerous neuronal processes, ranging from effects on membrane fluidity to gene expression regulation. Deficiencies and imbalances of these nutrients, not only during the developmental phase but throughout the whole life span, have significant effects on brain function. Numerous observational studies have shown a link between childhood developmental disorders and omega-6:omega-3 fatty acid imbalances. For instance, neurocognitive disorders such as attention-deficit hyperactivity disorder (ADHD), dyslexia, dyspraxia and autism spectrum disorders are often associated with a relative lack of omega-3 fatty acids. In addition to a high omega-6 fatty acid intake and, in many cases, an insufficient supply of omega-3 fatty acids among the population, evidence is increasing to suggest that PUFA metabolism can be impaired in individuals with ADHD. In this context, PUFA imbalances are being discussed as potential risk factors for neurodevelopmental disorders. Another focus is whether the nutritive PUFA requirements-especially long-chain omega-3 fatty acid requirements-are higher among some individuals. Meanwhile, several controlled studies investigated the clinical benefits of LC-PUFA supplementation in affected children and adolescents, with occasionally conflicting results. PMID:19672626

  11. Effect of surface pretreatments on resin composite bonding to PEEK.

    PubMed

    Silthampitag, Patcharawan; Chaijareenont, Pisaisit; Tattakorn, Kittipong; Banjongprasert, Chaiyasit; Takahashi, Hidekazu; Arksornnukit, Mansuang

    2016-01-01

    This study evaluated the effect of surface pretreatments on resin composite bonding to polyetheretherketone (PEEK). Four groups of surface pretreatment (no pretreatment, etched with 98% sulfuric acid, etched with piranha solution and sandblasting with 50 µm alumina) were performed on PEEK. Surface roughness, Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were examined. Shear bond strength (SBS) and interface characteristics were also evaluated after the specimens were bonded with resin materials. Two-way ANOVA analysis revealed significance on two main effects and interactions. Tukey's multiple comparisons test showed that the SBS of resin composite on PEEK were the highest in the group etched with 98% sulfuric acid and bonded with Heliobond(®) (p<0.05). All pretreatments produced similar spectra of FTIR patterns. SEM demonstrated porosities and pitting from chemical etching, which suggested a significant influence on the adhesion between PEEK and resin materials. PMID:27477234

  12. A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

    PubMed

    Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

    2016-11-01

    A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. PMID:27543312

  13. Pretreatment of cultured preadipocytes with arachidonic acid during the differentiation phase without a cAMP-elevating agent enhances fat storage after the maturation phase.

    PubMed

    Khan, Ferdous; Syeda, Pinky Karim; Nartey, Michael Nii N; Rahman, Mohammad Shahidur; Islam, Mohammad Safiqul; Nishimura, Kohji; Jisaka, Mitsuo; Shono, Fumiaki; Yokota, Kazushige

    2016-03-01

    Arachidonic acid (AA) and the related prostanoids exert complex effects on the adipocyte differentiation depending on the culture conditions and life stages. Here, we investigated the effect of the pretreatment of cultured 3T3-L1 preadipocytes with exogenous AA during the differentiation phase without 3-isobutyl-1-methylxanthine (IBMX), a cAMP-elevating agent, on the storage of fats after the maturation phase. This pretreatment with AA stimulated appreciably adipogenesis after the maturation phase as evident with the up-regulated gene expression of adipogenic markers. The stimulatory effect of the pretreatment with AA was attenuated by the co-incubation with each of cyclooxygenase (COX) inhibitors. Among exogenous prostanoids and related compounds, the pretreatment with MRE-269, a selective agonist of the IP receptor for prostaglandin (PG) I2, strikingly stimulated the storage of fats in adipocytes. The gene expression analysis of arachidonate COX pathway revealed that the transcript levels of inducible COX-2, membrane-bound PGE synthase-1, and PGF synthase declined more greatly in cultured preadipocytes treated with AA. By contrast, the expression levels of COX-1, cytosolic PGE synthase, and PGI synthase remained constitutive. The treatment of cultured preadipocytes with AA resulted in the decreased synthesis of PGE2 and PGF2α serving as anti-adipogenic PGs although the biosynthesis of pro-adipogenic PGI2 was up-regulated during the differentiation phase. Moreover, the gene expression levels of EP4 and FP, the respective prostanoid receptors for PGE2 and PGF2α, were gradually suppressed by the supplementation with AA, whereas that of IP for PGI2 remained relatively constant. Collectively, these results suggest the predominant role of endogenous PGI2 in the stimulatory effect of the pretreatment of cultured preadipoccytes with AA during the differentiation phase without IBMX on adipogenesis after the maturation phase. PMID:26928048

  14. PRETREATING THORIUM FOR ELECTROPLATING

    DOEpatents

    Beach, J.G.; Schaer, G.R.

    1959-07-28

    A method is presented for pretreating a thorium surface prior to electroplating the surface. The pretreatment steps of the invention comprise cleaning by vapor blasting the surface, anodically pickling in a 5 to 15% by volume aqueous hydrochloric acid bath with a current of 125 to 250 amp/sq ft for 3 to 5 min at room temperature, chemically pickling the surface in a 5 to 15% by volume of aqueous sulfuric acid for 3 to 5 min at room temperature, and rinsing the surface with water.

  15. Experimental study and neural network modeling of sugarcane bagasse pretreatment with H2SO4 and O3 for cellulosic material conversion to sugar.

    PubMed

    Gitifar, Vahid; Eslamloueyan, Reza; Sarshar, Mohammad

    2013-11-01

    In this study, pretreatment of sugarcane bagasse and subsequent enzymatic hydrolysis is investigated using two categories of pretreatment methods: dilute acid (DA) pretreatment and combined DA-ozonolysis (DAO) method. Both methods are accomplished at different solid ratios, sulfuric acid concentrations, autoclave residence times, bagasse moisture content, and ozonolysis time. The results show that the DAO pretreatment can significantly increase the production of glucose compared to DA method. Applying k-fold cross validation method, two optimal artificial neural networks (ANNs) are trained for estimations of glucose concentrations for DA and DAO pretreatment methods. Comparing the modeling results with experimental data indicates that the proposed ANNs have good estimation abilities. PMID:24035818

  16. Five year evaluation of class III composite resin restorations in cavities pre-treated with an oxalic- or a phosphoric acid conditioner.

    PubMed

    van Dijken, J W; Olofsson, A L; Holm, C

    1999-05-01

    An oxalic acid solution has been proposed as a conditioning agent for resin composite restorations in two commercial adhesive systems. The durability of 163 class III restorations, including 12 class IV restorations, in cavities pre-treated with an oxalic acid total etch technique or an enamel etch with phosphoric acid was studied. Each of 52 patients received at least one of each of three experimental restorations. The restorations were evaluated yearly with slightly modified United States Public Health Service (USPHS) criteria. After 5 years 95% of the restorations were evaluated as acceptable. Reasons for failure were the fracture of four fillings, including three class IV, secondary caries contiguous to two fillings and a non-acceptable colour match for one restoration. For eight class III restorations a fracture of the incisal tooth structure was registered. No differences were seen between the three experimental restorations. PMID:10373082

  17. Impact of surfactant assisted acid and alkali pretreatment on lignocellulosic structure of pine foliage and optimization of its saccharification parameters using response surface methodology.

    PubMed

    Pandey, Ajay Kumar; Negi, Sangeeta

    2015-09-01

    In present study, two hybrid methods such as surfactant assisted acid pretreatment (SAAP) and surfactant assisted base pretreatment (SABP) of pine foliage (PF) were found efficient for removal of 59.53 ± 0.76% and 73.47 ± 1.03% lignin, respectively. Assessment of the impact of pretreatment over the structure of PF were studied by scanning electron microscopy, Fourier transform infrared and X-ray diffraction analysis. Parameters for saccharification of SAAP and SABP biomass were optimized by Box-Behnken design method and 0.588 g/g and 0.477 g/g of reducing sugars were obtained, respectively. The ethanol fermentation efficiency of Saccharomyces cerevisiae (NCIM 3288) of hydrolysates was increased by 16.1% and 6.01% in SAAP-PFF and SABP-PFF after detoxification with XAD-4 resin. The mass balance analysis of the process showed that 67.7% and 70.12% cellulose were utilized during SAAP and SABP, respectively. These results indicated that SAAP would be more economic for bioethanol production. PMID:26025349

  18. Fermentative l-lactic acid production from pretreated whole slurry of oil palm trunk treated by hydrothermolysis and subsequent enzymatic hydrolysis.

    PubMed

    Eom, In-Yong; Oh, Young-Hoon; Park, Si Jae; Lee, Seung-Hwan; Yu, Ju-Hyun

    2015-06-01

    A simple and cost-effective biochemical conversion process consisting of hydrothermal treatment, enzymatic hydrolysis and fermentation of pretreated whole slurry (PWS) was developed for producing l-lactic acid (L-LA) from oil palm trunk (OPT). When OPT was hydrothermally treated at optimal condition capable of achieving maximum yield of hemicellulosic sugars after enzymatic hydrolysis, the enzymatic digestibility of the PWS afforded a yield of 81.4% of the theoretical glucose yield (TGY). However, glucose yield from washed pretreated solid (WPS) was only 43.5% of TGY. The use of two hydrolysates from PWS and WPS for fermentation by Lactobacillus paracasei engineered to selectively produce L-LA afforded yields of 89.5% and 45.8% of the theoretical LA yield (TLY), respectively. This study confirmed the inevitable extensive sugar loss during washing of pretreated slurry due to loss of soluble starch. Alternatively, the proposed design process is considered suitable for converting OPT to L-LA without such starch loss. PMID:25768416

  19. Modulation of extracellular signal-related kinase, cyclin D1, glial fibrillary acidic protein, and vimentin expression in estradiol-pretreated astrocyte cultures treated with competence and progression growth factors.

    PubMed

    Bramanti, Vincenzo; Grasso, Sonia; Tibullo, Daniele; Giallongo, Cesarina; Raciti, Giuseppina; Viola, Maria; Avola, Roberto

    2015-09-01

    The present study seeks to elucidate the interactions between the "competence" growth factor basic fibroblast growth factor (bFGF) and/or estrogen 17β-estradiol and the "progression" growth factors epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and insulin (INS) on DNA labeling and also cyclin D1, extracellular signal-related kinase 1/2 (ERK1/2), glial fibrillary acidic protein (GFAP), and vimentin expression in astroglial cultures under different experimental conditions. Pretreatment for 24 hr with bFGF and subsequent exposure for 36 hr to estradiol (E2 ) and EGF, IGF-I, or INS stimulated DNA labeling in the last 12 hr, especially when the cultures were treated with progression growth factors. bFGF pretreatment and subsequent treatment with E2 for 36 hr stimulated DNA labeling. The 36-hr E2 treatment alone did not significantly decrease DNA labeling, but contemporary addition of E2 with two or three growth factors stimulated DNA labeling remarkably. When E2 was coadded with growth factors, a significantly increased DNA labeling was observed, demonstrating an astroglial synergistic mitogenic effect evoked by contemporary treatment with growth factors in the presence of estrogens. Cyclin D1 expression was markedly increased when astrocyte cultures were pretreated for 36 hr with E2 and subsequently treated with two or three competence and progression growth factors. A highly significant increase of ERK1/2 expression was observed after all the treatments (EGF, bFGF, INS, IGF-I alone or in combination with two or three growth factors). GFAP and vimentin expression was markedly increased when the cultures were treated with two or three growth factors. In conclusion, our data demonstrate estradiol-growth factor cross-talk during astroglial cell proliferation and differentiation in culture. PMID:26053243

  20. Identification of significant medium components that affect docosahexaenoic acid production by Schizochytrium sp. SW1

    NASA Astrophysics Data System (ADS)

    Manikan, Vidyah; Hamid, Aidil A.

    2013-11-01

    Central composite design (CCD) was employed to investigate the significance of glucose, yeast extract, MSG and sea salt in affecting the amount of docosahexaenoic acid (DHA) accumulated by a locally isolated strain of Schizochytrium. Design Expert software was used to construct a set of experiments where each medium component mentioned above was varied over three levels. Cultivation was carried out in 250mL flasks containing 50mL of medium, incubated at 30°C with 200 rpm agitation for 96 hours. ANOVA was conducted to identify the influential factors and the level of their significance where factors that scored a probability value of less than 0.05 were considered significant. The level of influence for each independent variable was also interpreted using perturbation whereas pattern of interaction between the factors were interpreted using interaction plots. This experiment revealed that yeast extract and monosodium glutamate have significant influence on DHA accumulation process by Schizochytrium sp. SW1.

  1. Natural variation in the glucose content of dilute sulfuric acid-pretreated rice straw liquid hydrolysates: implications for bioethanol production.

    PubMed

    Goda, Takashi; Teramura, Hiroshi; Suehiro, Miki; Kanamaru, Kengo; Kawaguchi, Hideo; Ogino, Chiaki; Kondo, Akihiko; Yamasaki, Masanori

    2016-05-01

    Rice straw is a promising resource for bioethanol production. Because the glucose content of pretreatment liquid hydrolysates is highly correlated with ethanol yield, the selection of appropriate rice cultivars is essential. The glucose content in liquid hydrolysates of pretreated rice straws of 208 diverse cultivars was evaluated in natural field in 2013 and 2014 using a novel high-throughput system. The glucose content of the rice straw samples varied across cultivars and was affected by environmental factors such as temperature and solar radiation. Several high-quality cultivars exhibiting high glucose content in both years were identified. The results of this study can aid in development of novel rice cultivars suitable as both feedstocks for bioethanol production and cooking. PMID:26872499

  2. Lime pretreatment of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Chang, Shushien

    Lignocellulose is a valuable alternative energy source. The susceptibility of lignocellulosic biomass to enzymatic hydrolysis is constrained due to its structural features, so pretreatment is essential to enhance enzymatic digestibility. Of the chemicals used as pretreatment agents, it has been reported that alkalis improve biomass digestibility significantly. In comparison with other alkalis such as NaOH and ammonia, lime (calcium hydroxide) has many advantages; it is very inexpensive, is safe, and can be recovered by carbonating wash water. The effects of lime pretreatment were explored on switchgrass and poplar wood, representing herbaceous and woody biomass, respectively. The effects of pretreatment conditions (time, temperature, lime loading, water loading, particle size, and oxygen pressure) have been systematically studies. Lime alone enhances the digestibility of switchgrass significantly; under the recommended conditions, the 3-d total sugar (glucose + xylose) yields of lime-treated switchgrass were 7 times that of untreated sample. When treating poplar wood, lime must be combined with oxygen to achieve high digestibility; oxidative lime pretreatment increased the 3-d total sugar yield of poplar wood to 12 times that of untreated sample. In a fundamental study, to determine why lime pretreatment is effective, the effects of three structural features on enzymatic digestibility were studied: lignin content, acetyl content, and crystallinity index (CrI). Poplar wood was treated with peracetic acid, potassium hydroxide, and ball milling to produce model lignocelluloses with a broad spectrum of lignin contents, acetyl contents, and CrI, respectively. Enzymatic hydrolysis was performed on the model lignocelluloses to determine the digestibility. Correlations between lignin/carbohydrate ratio, acetyl/carbohydrate ratio, CrI and digestibility were developed. The 95% prediction intervals show that the correlations predict the 1-h and 3-d total sugar conversions of

  3. Acetic acid-catalyzed hydrothermal pretreatment of corn stover for the production of bioethanol at high-solids content.

    PubMed

    Katsimpouras, Constantinos; Christakopoulos, Paul; Topakas, Evangelos

    2016-09-01

    Corn stover (CS) was hydrothermally pretreated using CH3COOH (0.3 %, v/v), and subsequently its ability to be utilized for conversion to ethanol at high-solids content was investigated. Pretreatment conditions were optimized employing a response surface methodology (RSM) with temperature and duration as independent variables. Pretreated CS underwent a liquefaction/saccharification step at a custom designed free-fall mixer at 50 °C for either 12 or 24 h using an enzyme loading of 9 mg/g dry matter (DM) at 24 % (w/w) DM. Simultaneous enzymatic saccharification and fermentation (SSF) of liquefacted corn stover resulted in high ethanol concentration (up to 36.8 g/L), with liquefaction duration having a negligible effect. The threshold of ethanol concentration of 4 % (w/w), which is required to reduce the cost of ethanol distillation, was surpassed by the addition of extra enzymes at the start up of SSF achieving this way ethanol titer of 41.5 g/L. PMID:27145780

  4. The organic geochemistry of black sedimentary barite: significance and implications of trapped fatty acids

    USGS Publications Warehouse

    Miller, R.E.; Brobst, D.A.; Beck, P.C.

    1977-01-01

    Fatty acids isolated in sedimentary black barite (BaSO4) from Arkansas and Nevada were identified by gas chromatography-mass spectroscopy. The dominant or major fatty acids found in these beds of barite are C16:0, C18:0, and C18:1. The occurrence and distribution of these acids in this type of rock may serve as "molecular fingerprints" of microbial biogeochemical processes. The organic matter and associated microorganisms are shown to be trapped within the finely crystalline barite, thus forming a closed system for microbial diagenesis. Important differences that occur in the distribution of the lesser or minor fatty acids probably result from: (1) the nature of the progenitor organic detritus in the environment of barite deposition: and (2) the subsequent degree of microbiological alteration of the parent organic debris swept into and trapped in the depositional environment. Three general models of sedimentary environments are proposed in which anoxic conditions may prevail and where barium sulfate (BaSO4) may precipitate: (1) in a silled basin with semi-restricted circulation; (2) on an outer continental shelf where the slope is encroached upon by water of the oxygen minimum layer; (3) on a low-energy, inner shelf or semi-restricted embayment impinged by a wedge of anoxic water. The major geochemical and geological parameters which are believed to be the significant factors controlling the formation and high grade of these organic-rich, black bedded barites are: (1) a unique source of barium-rich fluid that only contains trace amounts of other elements; (2) the presence of an anoxic bottom environment within the depositional basin; (3) a reflux source of sulfate ion; (4) an adequate source of organic matter. The results of this study may serve as guidelines for future exploration in similar, untested sedimentary basins, especially those with rocks of middle Paleozoic age. ?? 1977.

  5. Hippuric Acid as a Significant Regulator of Supersaturation in Calcium Oxalate Lithiasis: The Physiological Evidence

    PubMed Central

    Atanassova, Stoyanka S.; Gutzow, Ivan S.

    2013-01-01

    At present, the clinical significance of existing physicochemical and biological evidence and especially the results we have obtained from our previous in vitro experiments have been analyzed, and we have come to the conclusion that hippuric acid (C6H5CONHCH2COOH) is a very active solvent of Calcium Oxalate (CaOX) in physiological solutions. Two types of experiments have been discussed: clinical laboratory analysis on the urine excretion of hippuric acid (HA) in patients with CaOX lithiasis and detailed measurements of the kinetics of the dissolution of CaOX calculi in artificial urine, containing various concentrations of HA. It turns out that the most probable value of the HA concentration in the control group is approximately ten times higher than the corresponding value in the group of the stone-formers. Our in vitro analytical measurements demonstrate even a possibility to dissolve CaOX stones in human urine, in which increased concentration of HA have been established. A conclusion can be that drowning out HA is a significant regulator of CaOX supersaturation and thus a regulation of CaOX stone formation in human urine. Discussions have arisen to use increased concentration of HA in urine both as a solubilizator of CaOX stones in the urinary tract and on the purpose of a prolonged metaphylactic treatment. PMID:24307993

  6. Acid-base titrations for polyacids: Significance of the pK sub a and parameters in the Kern equation

    NASA Technical Reports Server (NTRS)

    Meites, L.

    1978-01-01

    A new method is suggested for calculating the dissociation constants of polyvalent acids, especially polymeric acids. In qualitative form the most significant characteristics of the titration curves are demonstrated and identified which are obtained when titrating the solutions of such acids with a standard base potentiometrically.

  7. The Expression and Prognostic Significance of Retinoic Acid Metabolising Enzymes in Colorectal Cancer

    PubMed Central

    Brown, Gordon T.; Cash, Beatriz Gimenez; Blihoghe, Daniela; Johansson, Petronella; Alnabulsi, Ayham; Murray, Graeme I.

    2014-01-01

    Colorectal cancer is one of the most common types of cancer with over fifty percent of patients presenting at an advanced stage. Retinoic acid is a metabolite of vitamin A and is essential for normal cell growth and aberrant retinoic acid metabolism is implicated in tumourigenesis. This study has profiled the expression of retinoic acid metabolising enzymes using a well characterised colorectal cancer tissue microarray containing 650 primary colorectal cancers, 285 lymph node metastasis and 50 normal colonic mucosal samples. Immunohistochemistry was performed on the tissue microarray using monoclonal antibodies which we have developed to the retinoic acid metabolising enzymes CYP26A1, CYP26B1, CYP26C1 and lecithin retinol acyl transferase (LRAT) using a semi-quantitative scoring scheme to assess expression. Moderate or strong expression of CYP26A1was observed in 32.5% of cancers compared to 10% of normal colonic epithelium samples (p<0.001). CYP26B1 was moderately or strongly expressed in 25.2% of tumours and was significantly less expressed in normal colonic epithelium (p<0.001). CYP26C1 was not expressed in any sample. LRAT also showed significantly increased expression in primary colorectal cancers compared with normal colonic epithelium (p<0.001). Strong CYP26B1 expression was significantly associated with poor prognosis (HR = 1.239, 95%CI = 1.104–1.390, χ2 = 15.063, p = 0.002). Strong LRAT was also associated with poorer outcome (HR = 1.321, 95%CI = 1.034–1.688, χ2 = 5.039, p = 0.025). In mismatch repair proficient tumours strong CYP26B1 (HR = 1.330, 95%CI = 1.173–1.509, χ2 = 21.493, p<0.001) and strong LRAT (HR = 1.464, 95%CI = 1.110–1.930, χ2 = 7.425, p = 0.006) were also associated with poorer prognosis. This study has shown that the retinoic acid metabolising enzymes CYP26A1, CYP26B1 and LRAT are significantly overexpressed in colorectal cancer and that CYP26B1 and LRAT are

  8. Pretreatment with β-Boswellic Acid Improves Blood Stasis Induced Endothelial Dysfunction: Role of eNOS Activation.

    PubMed

    Wang, Mingming; Chen, Minchun; Ding, Yi; Zhu, Zhihui; Zhang, Yikai; Wei, Peifeng; Wang, Jingwen; Qiao, Yi; Li, Liang; Li, Yuwen; Wen, Aidong

    2015-01-01

    Vascular endothelial cells play an important role in modulating anti-thrombus and maintaining the natural function of vascular by secreting many active substances. β-boswellic acid (β-BA) is an active triterpenoid compound from the extract of boswellia serrate. In this study, it is demonstrated that β-BA ameliorates plasma coagulation parameters, protects endothelium from blood stasis induced injury and prevents blood stasis induced impairment of endothelium-dependent vasodilatation. Moreover, it is found that β-BA significantly increases nitric oxide (NO) and cyclic guanosine 3', 5'-monophosphate (cGMP) levels in carotid aortas of blood stasis rats. To stimulate blood stasis-like conditions in vitro, human umbilical vein endothelial cells (HUVECs) were exposed to transient oxygen and glucose deprivation (OGD). Treatment of β-BA significantly increased intracellular NO level. Western blot and immunofluorescence as well as immunohistochemistry reveal that β-BA increases phosphorylation of enzyme nitric oxide synthase (eNOS) at Ser1177. In addition, β-BA mediated endothelium-dependent vasodilatation can be markedly blocked by eNOS inhibitor L-NAME in blood stasis rats. In OGD treated HUEVCs, the protective effect of β-BA is attenuated by knockdown of eNOS. In conclusion, the above findings provide convincing evidence for the protective effects of β-BA on blood stasis induced endothelial dysfunction by eNOS signaling pathway. PMID:26482008

  9. Pretreatment with β-Boswellic Acid Improves Blood Stasis Induced Endothelial Dysfunction: Role of eNOS Activation

    PubMed Central

    Wang, Mingming; Chen, Minchun; Ding, Yi; Zhu, Zhihui; Zhang, Yikai; Wei, Peifeng; Wang, Jingwen; Qiao, Yi; Li, Liang; Li, Yuwen; Wen, Aidong

    2015-01-01

    Vascular endothelial cells play an important role in modulating anti-thrombus and maintaining the natural function of vascular by secreting many active substances. β-boswellic acid (β-BA) is an active triterpenoid compound from the extract of boswellia serrate. In this study, it is demonstrated that β-BA ameliorates plasma coagulation parameters, protects endothelium from blood stasis induced injury and prevents blood stasis induced impairment of endothelium-dependent vasodilatation. Moreover, it is found that β-BA significantly increases nitric oxide (NO) and cyclic guanosine 3’, 5’-monophosphate (cGMP) levels in carotid aortas of blood stasis rats. To stimulate blood stasis-like conditions in vitro, human umbilical vein endothelial cells (HUVECs) were exposed to transient oxygen and glucose deprivation (OGD). Treatment of β-BA significantly increased intracellular NO level. Western blot and immunofluorescence as well as immunohistochemistry reveal that β-BA increases phosphorylation of enzyme nitric oxide synthase (eNOS) at Ser1177. In addition, β-BA mediated endothelium-dependent vasodilatation can be markedly blocked by eNOS inhibitor L-NAME in blood stasis rats. In OGD treated HUEVCs, the protective effect of β-BA is attenuated by knockdown of eNOS. In conclusion, the above findings provide convincing evidence for the protective effects of β-BA on blood stasis induced endothelial dysfunction by eNOS signaling pathway. PMID:26482008

  10. Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol: Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover

    SciTech Connect

    Humbird, D.; Davis, R.; Tao, L.; Kinchin, C.; Hsu, D.; Aden, A.; Schoen, P.; Lukas, J.; Olthof, B.; Worley, M.; Sexton, D.; Dudgeon, D.

    2011-03-01

    This report describes one potential biochemical ethanol conversion process, conceptually based upon core conversion and process integration research at NREL. The overarching process design converts corn stover to ethanol by dilute-acid pretreatment, enzymatic saccharification, and co-fermentation. Building on design reports published in 2002 and 1999, NREL, together with the subcontractor Harris Group Inc., performed a complete review of the process design and economic model for the biomass-to-ethanol process. This update reflects NREL's current vision of the biochemical ethanol process and includes the latest research in the conversion areas (pretreatment, conditioning, saccharification, and fermentation), optimizations in product recovery, and our latest understanding of the ethanol plant's back end (wastewater and utilities). The conceptual design presented here reports ethanol production economics as determined by 2012 conversion targets and 'nth-plant' project costs and financing. For the biorefinery described here, processing 2,205 dry ton/day at 76% theoretical ethanol yield (79 gal/dry ton), the ethanol selling price is $2.15/gal in 2007$.

  11. Enhancing anaerobic digestion of cotton stalk by pretreatment with a microbial consortium (MC1).

    PubMed

    Yuan, Xufeng; Ma, Lei; Wen, Boting; Zhou, Dayun; Kuang, Meng; Yang, Weihua; Cui, Zongjun

    2016-05-01

    Microbial pretreatment is beneficial in some anaerobic digestion systems, but the consortia used to date have not been able to effectively increase methane production from cotton stalk. In this study, a thermophilic microbial consortium (MC1) was used for pretreatment in order to enhance biogas and methane production yields. The results indicated that the concentrations of soluble chemical oxygen demand and volatile organic products increased significantly in the early stages of pretreatment. Ethanol, acetic acid, propionic acid, and butyric acid were the predominant volatile organic products in the MC1 hydrolysate. Biogas and methane production yields from cotton stalk were significantly increased following MC1 pretreatment. In addition, the methane production rate from the treated cotton stalk was greater than that from the untreated sample. PMID:26896713

  12. Prognostic significance of periodic acid-Schiff-positive patterns in primary cutaneous melanoma.

    PubMed

    Warso, M A; Maniotis, A J; Chen, X; Majumdar, D; Patel, M K; Shilkaitis, A; Gupta, T K; Folberg, R

    2001-03-01

    The patterns of periodic acid-Schiff (PAS) staining of extracellular matrix in histological sections of certain melanomas may be predictive of outcome. Recent in vitro and molecular genetic data suggest that the appearance of these patterns in both uveal and cutaneous melanoma is a function of aggressive tumor cells. We studied 96 patients with primary cutaneous melanomas treated at the University of Illinois at Chicago who were monitored for disease-free survival. Survival probabilities were determined by Kaplan-Meier estimates, and prognostic factors were evaluated by multivariate analysis. By univariate analysis, there was a significant decrease in disease-free survival among patients whose tumors contained parallel with cross-linking or network patterns (PXNs; P = 0.0070). Stepwise regression with Cox models that included the combinations of the PAS-positive patterns, tumor thickness, female gender, ulceration, and age yielded a model with thickness and the PAS-positive parallel with cross-linking or networks. Despite the relatively small sample size in this study, the detection of the PAS-positive parallel with cross-linking or networking in cutaneous melanoma was associated with a decrease in disease-free outcome. Additional studies of the prognostic significance of these patterns is warranted on larger data sets. PMID:11297236

  13. Acid-Assisted Ball Milling of Cellulose as an Efficient Pretreatment Process for the Production of Butyl Glycosides.

    PubMed

    Boissou, Florent; Sayoud, Nassim; De Oliveira Vigier, Karine; Barakat, Abdellatif; Marinkovic, Sinisa; Estrine, Boris; Jérôme, François

    2015-10-12

    Ball milling of cellulose in the presence of a catalytic amount of H2SO4 was found to be a promising pre-treatment process to produce butyl glycosides in high yields. Conversely to the case of water, n-butanol has only a slight effect on the recrystallization of ball-milled cellulose. As a result, thorough depolymerization of cellulose prior the glycosylation step is no longer required, which is a pivotal aspect with respect to energy consumption. This process was successfully transposed to wheat straw from which butyl glycosides and xylosides were produced in good yields. Butyl glycosides and xylosides are important chemicals as they can be used as hydrotropes but also as intermediates in the production of valuable amphiphilic alkyl glycosides. PMID:26346950

  14. Kinetic features of xylan de-polymerization in production of xylose monomer and furfural during acid pretreatment for kenaf, forage sorghums and sunn hemp feedstocks

    SciTech Connect

    Kamireddy, Srinivas Reddy; Kozliak, Evguenii I.; Tucker, Melvin; Ji, Yun

    2014-08-01

    A kinetic study of acid pretreatment was conducted for sorghum non-brown mid rib (SNBMR) (Sorghum bicolor L Moench), sorghum-brown mid rib (SBMR), sunn hemp (Crotalaria juncea L) and kenaf (Gossypiumhirsutum L), focusing on rates of xylose monomer and furfural formation. The kinetics was investigated using two independent variables, reaction temperature (150 and 160°C) and acid concentration (1 and 2 wt%), with a constant dry biomass loading of 10 wt% and a treatment time up to 20 min while sampling the mixture every 2 min. The experimental data were fitted using a two-step kinetic model based on irreversible pseudo first order kinetics at each step. Varied kinetic orders on the acid concentration, ranging from 0.2 to >3, were observed for both xylose and furfural formation, the values depending on the feedstock. The crystallinity index of raw biomass was shown to be a major factor influencing the rate of both xylose and furfural formation. As a result, a positive correlation was observed between the activation energy and biomass crystallinity index for xylose formation.

  15. Kinetic features of xylan de-polymerization in production of xylose monomer and furfural during acid pretreatment for kenaf, forage sorghums and sunn hemp feedstocks

    DOE PAGESBeta

    Kamireddy, Srinivas Reddy; Kozliak, Evguenii I.; Tucker, Melvin; Ji, Yun

    2014-08-01

    A kinetic study of acid pretreatment was conducted for sorghum non-brown mid rib (SNBMR) (Sorghum bicolor L Moench), sorghum-brown mid rib (SBMR), sunn hemp (Crotalaria juncea L) and kenaf (Gossypiumhirsutum L), focusing on rates of xylose monomer and furfural formation. The kinetics was investigated using two independent variables, reaction temperature (150 and 160°C) and acid concentration (1 and 2 wt%), with a constant dry biomass loading of 10 wt% and a treatment time up to 20 min while sampling the mixture every 2 min. The experimental data were fitted using a two-step kinetic model based on irreversible pseudo first ordermore » kinetics at each step. Varied kinetic orders on the acid concentration, ranging from 0.2 to >3, were observed for both xylose and furfural formation, the values depending on the feedstock. The crystallinity index of raw biomass was shown to be a major factor influencing the rate of both xylose and furfural formation. As a result, a positive correlation was observed between the activation energy and biomass crystallinity index for xylose formation.« less

  16. Dilute sulfuric acid pretreatment of corn stover for enzymatic hydrolysis and efficient ethanol production by recombinant Escherichia coli FBR5 without detoxification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pretreatment strategy for dilute H2SO4 pretreatment of corn stover was developed for the purpose of reducing the generation of inhibitory substances during pretreatment so that a detoxification step is not required prior to fermentation while maximizing the sugar yield. We have optimized dilute su...

  17. Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

    NASA Technical Reports Server (NTRS)

    Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

    1980-01-01

    The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

  18. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    PubMed

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. PMID:23617813

  19. Effects of β-glucan pretreatment on acetylsalicylic acid-induced gastric damage: An experimental study in rats

    PubMed Central

    Ozkan, Orhan Veli; Ozturk, Oktay Hasan; Aydin, Mehmet; Yilmaz, Nigar; Yetim, Ibrahim; Nacar, Ahmet; Oktar, Suleyman; Sogut, Sadik

    2010-01-01

    Background: NSAIDs have been found to induce gastrointestinal tract damage. Recently, it has been suggested that this might be mediated by lipid peroxidation. Objective: The aim of this study was to assess the potential protective effects of β-glucan against acetylsalicylic acid (ASA-induced gastric damage by means of its antioxidant capacity in an experimental rat model. Methods: Thirty-two male Wistar albino rats (200–250 g) were randomized into 4 groups consisting of 8 rats each. The β-glucan group received 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. The ASA group received saline once a day for 10 days and 300 mg/kg (20 mg/mL) ASA as a single dose, 4 hours before anesthesia. The ASA+β-glucan group was administered 50 mg/kg β-glucan once a day for 10 days and 30 minutes before anesthesia. Additionally, 300 mg/kg (20 mg/mL) ASA was administered as a single dose, 4 hours before anesthesia. The control group received saline once a day for 10 days and 30 minutes before anesthesia. All medications were administered by intragastric gavage. The stomach from each rat was dissected and divided into 2 parts for histologic and biochemical analysis. Gastric tissue malondialdehyde (MDA), nitric oxide (NO) levels, catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were determined for oxidative parameter analysis. Results: The gastroprotective and antioxidant effects of β-glucan appeared to attenuate the ASA-induced gastric tissue damage. Compared with the control group, MDA and NO levels and CAT and GSH-Px activities were significantly increased in the stomachs of ASA-treated rats (MDA, 4.12 [0.44] to 13.41 [1.05] μmol/L; NO, 8.04 [7.25–9.10] vs 30.35 [22.34–37.95] μmol/g protein; CAT, 0.050 [0.004] to 0.083 [0.003] k/g protein; GSH-Px, 0.57 [0.42–0.66] to 1.55 [1.19–1.76] U/L; all, P < 0.001), whereas SOD activity was significantly decreased in the same group (291 [29] to 124 [6] U/mL; P

  20. Changes in Lignin and Polysaccharide Components in 13 Cultivars of Rice Straw following Dilute Acid Pretreatment as Studied by Solution-State 2D 1H-13C NMR

    PubMed Central

    Teramura, Hiroshi; Sasaki, Kengo; Oshima, Tomoko; Aikawa, Shimpei; Matsuda, Fumio; Okamoto, Mami; Shirai, Tomokazu; Kawaguchi, Hideo; Ogino, Chiaki; Yamasaki, Masanori; Kikuchi, Jun; Kondo, Akihiko

    2015-01-01

    A renewable raw material, rice straw is pretreated for biorefinery usage. Solution-state two-dimensional (2D) 1H-13 C hetero-nuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy, was used to analyze 13 cultivars of rice straw before and after dilute acid pretreatment, to characterize general changes in the lignin and polysaccharide components. Intensities of most (15 of 16) peaks related to lignin aromatic regions, such as p-coumarate, guaiacyl, syringyl, p-hydroxyphenyl, and cinnamyl alcohol, and methoxyl, increased or remained unchanged after pretreatment. In contrast, intensities of most (11 of 13) peaks related to lignin aliphatic linkages or ferulate decreased. Decreased heterogeneity in the intensities of three peaks related to cellulose components in acid-insoluble residues resulted in similar glucose yield (0.45–0.59 g/g-dry biomass). Starch-derived components showed positive correlations (r = 0.71 to 0.96) with glucose, 5-hydroxymethylfurfural (5-HMF), and formate concentrations in the liquid hydrolysates, and negative correlations (r = –0.95 to –0.97) with xylose concentration and acid-insoluble residue yield. These results showed the fate of lignin and polysaccharide components by pretreatment, suggesting that lignin aromatic regions and cellulose components were retained in the acid insoluble residues and starch-derived components were transformed into glucose, 5-HMF, and formate in the liquid hydrolysate. PMID:26083431

  1. Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance.

    PubMed

    Sproul, Gordon

    2015-12-01

    Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life. PMID:26248658

  2. Abiogenic Syntheses of Lipoamino Acids and Lipopeptides and their Prebiotic Significance

    NASA Astrophysics Data System (ADS)

    Sproul, Gordon

    2015-12-01

    Researchers have formed peptide bonds under a variety of presumed prebiotic conditions. Here it is proposed that these same conditions would have also formed amide bonds between fatty acids and amino acids, producing phosphate-free amphipathic lipoamino acids and lipopeptides. These compounds are known to form vesicles and are ubiquitous in living organisms. They could represent molecules that provided protection by membranes as well as possibilities for proto-life metabolism . It is here demonstrated that when a fatty acid is heated with various amino acids, optimally in the presence of suitable salts or minerals, lipoamino acids are formed. Magnesium and potassium carbonates as well as iron (II) sulfide are found to be particularly useful in these reactions. In this manner N-lauroylglycine, N-lauroylalanine, N-stearoylalanine and several other lipoamino acids have been synthesized. Similarly, when glycylglycine was heated with lauric acid in the presence of magnesium carbonate, the lipopeptide N-lauroylglycylglycine was formed. Such compounds are proposed to have been critical precursors to the development of life.

  3. Pretreatment by NaOH swelling and then HCl regeneration to enhance the acid hydrolysis of cellulose to glucose.

    PubMed

    Sun, Binzhe; Peng, Gege; Duan, Lian; Xu, Aihua; Li, Xiaoxia

    2015-11-01

    A simple pretreatment method, NaOH swelling at a low temperature and then HCl regeneration, was developed for depolymerization of cellulose to glucose. Cellulose was transformed into amorphous hydrogel during the treatment; and due to the easy diffusion of H(+) and Cl(-) ions into the cellulose hydrogel network as well as the strong ability of Cl(-) to disrupt the massive hydrogen bond, the hydrolysis rate was greatly enhanced. The method is effective for α-cellulose, microcrystalline cellulose, filter paper, ramie fiber and absorbent cotton. Even at a high α-cellulose concentration of 50g/L, 29.1% yield of glucose was still obtained within 10min at 160°C under microwave irradiation, where up to 16.2g/L of glucose solution was given. The influence of NaOH concentration, HCl concentration, hydrolysis temperature and time on the hydrolysis rate was investigated. The structure of cellulose hydrogel was also studied to confirm the reaction mechanism. PMID:26280097

  4. Measurement of the inhibitory potential and detoxification of biomass pretreatment hydrolysate for ethanol production

    SciTech Connect

    Rivard, C.J.; Engel, R.E.; Nagle, N.J.

    1996-12-31

    The Microtox assay represents a rapid, accurate, and reproducible method for determining general microbial toxicity. This assay was used to evaluate the relative toxicity of a variety of hydrolysate samples derived from dilute-acid and alkaline biomass pretreatment. Toxicity is elicited from biomass degradation products, such as furfural, hydroxymethyl furfural, and acetic acid, generated during pretreatment. Microtox results indicate that the pretreatment samples examined ranged from 9 to 71 toxicity units (TU). Correlations of TU and sample absorbance at several wavelengths were evaluated for all sample series. Sample TU values best agreed with absorbance at 230 nm, but the unsatisfactory fit suggests that absorbance should not be used as an absolute measure of sample toxicity. Microtox data for pretreatment hydrolysate samples were correlated with the inhibition experienced by the ethanologenic yeast, Saccharomyces cerevisiae strain D{sub 5}A, during the simultaneous saccharification and fermentation (SSF) process of pretreated biomass. None of the alkaline pretreatment conditions produced inhibition during SSF. However, the acid pretreatment conditions did produce a wide range of inhibitory and noninhibitory hydrolysates. In general, fermentation was inhibited for acid-pretreated hydrolysate samples with values exceeding 45 TU. Preliminary studies that focused on reducing hydrolysate sample toxicity (detoxification) indicate that adding perlite and zeolite had little effect. However, the use of charcoal, a universal flocculent, or ion-exchange resins significantly reduced sample toxicity, holding promise for the efficient bioconversion of pretreated biomass to ethanol. Moreover, the developed toxicity measurement assay can quickly monitor the quality of the pretreatment process. In this way, biomass conversion operation processes can be reliably controlled at the pilot and commercial scales. 4 refs., 4 figs., 3 tabs.

  5. Studies of the prevalence and significance of radiolabeled bile acid malabsorption in a group of patients with idiopathic chronic diarrhea

    SciTech Connect

    Schiller, L.R.; Hogan, R.B.; Morawski, S.G.; Santa Ana, C.A.; Bern, M.J.; Norgaard, R.P.; Bo-Linn, G.W.; Fordtran, J.S.

    1987-01-01

    We studied radiolabeled fecal bile acid excretion in 11 normal subjects and 17 patients with idiopathic chronic diarrhea for three major purposes: to establish normal values for this test in the presence of increased stool volumes (induced in normal subjects by ingestion of poorly absorbable solutions); to test for bile acid malabsorption in the patients and to correlate this with an independent test of ileal function, the Schilling test; and to compare the results of the bile acid excretion test with the subsequent effect of a bile acid binding agent (cholestyramine) on stool weight. In normal subjects fecal excretion of the radiolabel was increased with increasing stool volumes. As a group, patients with idiopathic chronic diarrhea excreted radiolabeled bile acid more rapidly than normal subjects with induced diarrhea (t1/2 56 +/- 8 vs. 236 +/- 60 h, respectively, p less than 0.005). There was a statistically significant positive correlation between t1/2 of radiolabeled bile acid and Schilling test results in these patients. Although 14 of 17 patients absorbed labeled taurocholic acid less well than any of the normal subjects with comparable volumes of induced diarrhea, cholestyramine had no statistically significant effect on stool weight in the patient group, and in none of the patients was stool weight reduced to within the normal range. In summary, most patients with idiopathic chronic diarrhea have bile acid malabsorption (as measured by fecal excretion of labeled bile acid), but they do not respond to cholestyramine therapy with a significant reduction in stool weight. Although the significance of these findings was not clearly established, the most likely interpretation is that bile acid malabsorption is a manifestation of an underlying intestinal motility or absorptive defect rather than the primary cause of diarrhea.

  6. ALA Pretreatment Improves Waterlogging Tolerance of Fig Plants

    PubMed Central

    An, Yuyan; Qi, Lin; Wang, Liangju

    2016-01-01

    5-aminolevulinic acid (ALA), a natural and environmentally friendly plant growth regulator, can improve plant tolerance to various environmental stresses. However, whether ALA can improve plant waterlogging tolerance is unknown. Here, we investigated the effects of ALA pretreatment on the waterlogging-induced damage of fig (Ficus carica Linn.) plants, which often suffer from waterlogging stress. ALA pretreatment significantly alleviated stress-induced morphological damage, increased leaf relative water content (RWC), and reduced leaf superoxide anion (O2⋅¯) production rate and malonaldehyde (MDA) content in fig leaves, indicating ALA mitigates waterlogging stress of fig plants. We further demonstrated that ALA pretreatment largely promoted leaf chlorophyll content, photosynthetic electron transfer ability, and photosynthetic performance index, indicating ALA significantly improves plant photosynthetic efficiency under waterlogging stress. Moreover, ALA pretreatment significantly increased activities of leaf superoxide dismutase (SOD) and peroxidase (POD), root vigor, and activities of root alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH), indicating ALA also significantly improves antioxidant ability and root function of fig plants under waterlogging stress. Taken together, ALA pretreatment improves waterlogging tolerance of fig plants significantly, and the promoted root respiration, leaf photosynthesis, and antioxidant ability may contribute greatly to this improvement. Our data firstly shows that ALA can improve plant waterlogging tolerance. PMID:26789407

  7. ALA Pretreatment Improves Waterlogging Tolerance of Fig Plants.

    PubMed

    An, Yuyan; Qi, Lin; Wang, Liangju

    2016-01-01

    5-aminolevulinic acid (ALA), a natural and environmentally friendly plant growth regulator, can improve plant tolerance to various environmental stresses. However, whether ALA can improve plant waterlogging tolerance is unknown. Here, we investigated the effects of ALA pretreatment on the waterlogging-induced damage of fig (Ficus carica Linn.) plants, which often suffer from waterlogging stress. ALA pretreatment significantly alleviated stress-induced morphological damage, increased leaf relative water content (RWC), and reduced leaf superoxide anion ([Formula: see text]) production rate and malonaldehyde (MDA) content in fig leaves, indicating ALA mitigates waterlogging stress of fig plants. We further demonstrated that ALA pretreatment largely promoted leaf chlorophyll content, photosynthetic electron transfer ability, and photosynthetic performance index, indicating ALA significantly improves plant photosynthetic efficiency under waterlogging stress. Moreover, ALA pretreatment significantly increased activities of leaf superoxide dismutase (SOD) and peroxidase (POD), root vigor, and activities of root alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH), indicating ALA also significantly improves antioxidant ability and root function of fig plants under waterlogging stress. Taken together, ALA pretreatment improves waterlogging tolerance of fig plants significantly, and the promoted root respiration, leaf photosynthesis, and antioxidant ability may contribute greatly to this improvement. Our data firstly shows that ALA can improve plant waterlogging tolerance. PMID:26789407

  8. Occurrence of 3-hydroxy acids in microalgae and cyanobacteria and their geochemical significance

    NASA Astrophysics Data System (ADS)

    Matsumoto, Genki I.; Nagashima, Hideyuki

    1984-08-01

    3-Hydroxy acids were detected in pure cultured microalgae: Chlorophyta— Chlamydomonas reinhardtii and Chlorella pyrenoidosa and Rhodophyta— Cyanidium caldarium (two strains), and cyanobacteria (Cyanophyta)— Anacystis nidulans, Phormidium foveolarum, Anabaena variabilis and Oscillatoria sp. Normal and branched (iso and anteiso) 3-hydroxy acids in the ranges of C 8-C 26 were found in all the samples studied at concentrations ranging from 0.036 to 2.3 and 0.000 to 0.12 mg g -1 of dry sample, respectively. The major constituents were generally even-carbon numbered normal acids with carbon chain lengths below C 20. Microalgae and cyanobacteria may be the important sources of 3-hydroxy acids in natural environments.

  9. Effects of Temperature and Acidic Pre-Treatment on Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon

    EPA Science Inventory

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH ...

  10. Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

    EPA Science Inventory

    Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the p...

  11. Mechanism of waste biomass pyrolysis: Effect of physical and chemical pre-treatments.

    PubMed

    Das, Oisik; Sarmah, Ajit K

    2015-12-15

    To impart usability in waste based biomass through thermo-chemical reactions, several physical and chemical pre-treatments were conducted to gain an insight on their mode of action, effect on the chemistry and the change in thermal degradation profiles. Two different waste biomasses (Douglas fir, a softwood and hybrid poplar, a hardwood) were subjected to four different pre-treatments, namely, hot water pre-treatment, torrefaction, acid (sulphuric acid) and salt (ammonium phosphate) doping. Post pre-treatments, the changes in the biomass structure, chemistry, and thermal makeup were studied through electron microscopy, atomic absorption/ultra violet spectroscopy, ion exchange chromatography, and thermogravimetry. The pre-treatments significantly reduced the amounts of inorganic ash, extractives, metals, and hemicellulose from both the biomass samples. Furthermore, hot water and torrefaction pre-treatment caused mechanical disruption in biomass fibres leading to smaller particle sizes. Torrefaction of Douglas fir wood yielded more solid product than hybrid poplar. Finally, the salt pre-treatment increased the activation energies of the biomass samples (especially Douglas fir) to a great extent. Thus, salt pre-treatment was found to bestow thermal stability in the biomass. PMID:26282766

  12. Optimization and evaluation of alkaline potassium permanganate pretreatment of corncob.

    PubMed

    Ma, Lijuan; Cui, Youzhi; Cai, Rui; Liu, Xueqiang; Zhang, Cuiying; Xiao, Dongguang

    2015-03-01

    Alkaline potassium permanganate solution (APP) was applied to the pretreatment of corncob with a simple and effective optimization of APP concentration, reaction time, temperature and solid to liquid ratio (SLR). The optimized pretreatment conditions were at 2% (w/v) potassium permanganate with SLR of 1:10 treating for 6h at 50°C. This simple one-step treatment resulted in significant 94.56% of the cellulose and 81.47% of the hemicellulose recoveries and 46.79% of the lignin removal of corncob. The reducing sugar in the hydrolysate from APP-pretreated corncob was 8.39g/L after 12h enzymatic hydrolysis, which was 1.44 and 1.29 folds higher than those from raw and acid pretreated corncobs. Physical characteristics, crystallinity and structure of the pretreated corncob were analyzed and assessed by SEM, XRD and FTIR. The APP pretreatment process was novel and enhanced enzymatic hydrolysis of lignocellulose by affecting composition and structural features. PMID:25585256

  13. Fate of antibiotic resistance bacteria and genes during enhanced anaerobic digestion of sewage sludge by microwave pretreatment.

    PubMed

    Tong, Juan; Liu, Jibao; Zheng, Xiang; Zhang, Junya; Ni, Xiaotang; Chen, Meixue; Wei, Yuansong

    2016-10-01

    The fate of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) were investigated during the sludge anaerobic digestion (AD) with microwave-acid (MW-H), microwave (MW) and microwave-H2O2-alkaline (MW-H2O2) pretreatments. Results showed that combined MW pretreatment especially for the MW-H pretreatment could efficiently reduce the ARB concentration, and most ARG concentrations tended to attenuate during the pretreatment. The subsequent AD showed evident removal of the ARB, but most ARGs were enriched after AD. Only the concentration of tetX kept continuous declination during the whole sludge treatment. The total ARGs concentration showed significant correlation with 16S rRNA during the pretreatment and AD. Compared with unpretreated sludge, the AD of MW and MW-H2O2 pretreated sludge presented slightly better ARB and ARGs reduction efficiency. PMID:26970692

  14. Process and technoeconomic analysis of leading pretreatment technologies for lignocellulosic ethanol production using switchgrass.

    PubMed

    Tao, Ling; Aden, Andy; Elander, Richard T; Pallapolu, Venkata Ramesh; Lee, Y Y; Garlock, Rebecca J; Balan, Venkatesh; Dale, Bruce E; Kim, Youngmi; Mosier, Nathan S; Ladisch, Michael R; Falls, Matthew; Holtzapple, Mark T; Sierra, Rocio; Shi, Jian; Ebrik, Mirvat A; Redmond, Tim; Yang, Bin; Wyman, Charles E; Hames, Bonnie; Thomas, Steve; Warner, Ryan E

    2011-12-01

    Six biomass pretreatment processes to convert switchgrass to fermentable sugars and ultimately to cellulosic ethanol are compared on a consistent basis in this technoeconomic analysis. The six pretreatment processes are ammonia fiber expansion (AFEX), dilute acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide-impregnated steam explosion (SO(2)). Each pretreatment process is modeled in the framework of an existing biochemical design model so that systematic variations of process-related changes are consistently captured. The pretreatment area process design and simulation are based on the research data generated within the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) 3 project. Overall ethanol production, total capital investment, and minimum ethanol selling price (MESP) are reported along with selected sensitivity analysis. The results show limited differentiation between the projected economic performances of the pretreatment options, except for processes that exhibit significantly lower monomer sugar and resulting ethanol yields. PMID:21865030

  15. 40 CFR 417.34 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard... by Fatty Acid Neutralization Subcategory § 417.34 Pretreatment standards for existing sources....

  16. 40 CFR 417.34 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard... by Fatty Acid Neutralization Subcategory § 417.34 Pretreatment standards for existing sources....

  17. 40 CFR 417.34 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard... by Fatty Acid Neutralization Subcategory § 417.34 Pretreatment standards for existing sources....

  18. 40 CFR 417.34 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard... by Fatty Acid Neutralization Subcategory § 417.34 Pretreatment standards for existing sources....

  19. 40 CFR 417.34 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... treatment works must comply with 40 CFR part 403. In addition, the following pretreatment standard... by Fatty Acid Neutralization Subcategory § 417.34 Pretreatment standards for existing sources....

  20. Public health significance of supplementation or fortification of grain products with folic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The need for supplemental folate can be traced to the initial phase of the discovery of this vitamin as a micronutrient for the prevention of pregnancy related anemia. In the post discovery era, folic acid was used primarily to prevent deficiency as manifested by low blood folate levels and megalob...

  1. The Significance of Acid Alteration in the Los Humeros High-Temperature Geothermal Field, Puebla, Mexico.

    NASA Astrophysics Data System (ADS)

    Elders, W. A.; Izquierdo, G.

    2014-12-01

    The Los Humeros geothermal field is a high-enthalpy hydrothermal system with more than 40 drilled deep wells, mostly producing high steam fractions at > 300oC. However, although it has a large resource potential, low permeability and corrosive acid fluids have hampered development so that it currently has an installed electrical generating capacity of only 40 MWe. The widespread production of low pH fluids from the reservoir is inconsistent with the marked absence in the reservoir rocks of hydrothermal minerals typical of acid alteration. Instead the hydrothermal alteration observed is typical of that due to neutral to alkaline pH waters reacting with the volcanic rocks of the production zones. Thus it appears that since the reservoir has recently suffered a marked drop in fluid pressure and is in process of transitioning from being water-dominated to being vapor-dominated. However sparse examples of acid leaching are observed locally at depths of about 2 km in the form of bleached, intensely silicified zones, in low permeability and very hot (>350oC) parts of reservoir. Although these leached rocks retain their primary volcanic and pyroclastic textures, they are altered almost entirely to microcrystalline quartz, with some relict pseudomorphs of plagioclase phenocrysts and traces of earlier-formed hydrothermal chlorite and pyrite. These acid-altered zones are usually only some tens of meters thick and deeper rocks lack such silicification. The acid fluids responsible for their formation could either be magmatic volatiles, or could be formed during production (e.g. reaction of water and salts forming hydrogen chloride by hydrolysis at high temperatures). The very high boron content of the fluids produced by the Los Humeros wells suggests that their ultimate source is most likely magmatic gases. However, these acid gases did not react widely with the rocks. We suggest that the silicified zones are forming locally where colder descending waters are encountering

  2. Effect of pretreatments on extraction of pigment from marigold flower.

    PubMed

    Sowbhagya, Halagur B; Sushma, S B; Rastogi, Navin K; Naidu, M Madhava

    2013-02-01

    Marigold flower (Tagetes erecta L) is one of the richest sources of xanthophylls. An enzymatic pretreatment method was developed for improved extraction of pigments from marigold flowers. Pretreatment with enzyme solution increased the diffusion coefficient from 1.56 x 10(-9) m(2)/s to 4.02 x 10(-9) m(2)/s and mass transfer coefficient from 0.14 h(-1) to 0.36 h(-1) coefficients. At the same time, dry yield, resin yield and pigment yield were also found to increase along with increased retention of colour. Sodium hydroxide or citric acid pretreatments increased the diffusion coefficient during drying, but resulted in lower dry yield due to loss of soluble compounds whereas, pigment yield was higher as compared to control. The enzyme treated and air dried sample, stored at 4 °C was found to be the most stable, as indicated by a low (0.0006 day(-1)) degradation constant. Pretreatment of marigold flowers with an aqueous enzyme solution (0.2%) results in improved resin, pigment yield and retention of pigment during storage. Pretreatment of marigold flowers with sodium hydroxide citric acid followed by hydraulic pressing resulted in a significant reduction of water and also indicated improved dry yield, resin yield and pigment yield as compared to control sample. PMID:24425896

  3. Improving a recombinant Zymomonas mobilis strain 8b through continuous adaptation on dilute acid pretreated corn stover hydrolysate

    SciTech Connect

    Mohagheghi, Ali; Linger, Jeffrey G.; Yang, Shihui; Smith, Holly; Dowe, Nancy; Zhang, Min; Pienkos, Philip T.

    2015-03-31

    Complete conversion of the major sugars of biomass including both the C5 and C6 sugars is critical for biofuel production processes. Several inhibitory compounds like acetate, hydroxymethylfurfural (HMF), and furfural are produced from the biomass pretreatment process leading to ‘hydrolysate toxicity,’ a major problem for microorganisms to achieve complete sugar utilization. Therefore, development of more robust microorganisms to utilize the sugars released from biomass under toxic environment is critical. In this study, we use continuous culture methodologies to evolve and adapt the ethanologenic bacterium Zymomonas mobilis to improve its ethanol productivity using corn stover hydrolysate. The results are the following: A turbidostat was used to adapt the Z. mobilis strain 8b in the pretreated corn stover liquor. The adaptation was initiated using pure sugar (glucose and xylose) followed by feeding neutralized liquor at different dilution rates. Once the turbidostat reached 60% liquor content, the cells began washing out and the adaptation was stopped. Several ‘sub-strains’ were isolated, and one of them, SS3 (sub-strain 3), had 59% higher xylose utilization than the parent strain 8b when evaluated on 55% neutralized PCS (pretreated corn stover) liquor. Using saccharified PCS slurry generated by enzymatic hydrolysis from 25% solids loading, SS3 generated an ethanol yield of 75.5% compared to 64% for parent strain 8b. Furthermore, the total xylose utilization was 57.7% for SS3 versus 27.4% for strain 8b. To determine the underlying genotypes in these new sub-strains, we conducted genomic resequencing and identified numerous single-nucleotide mutations (SNPs) that had arisen in SS3. We further performed quantitative reverse transcription PCR (qRT-PCR) on genes potentially affected by these SNPs and identified significant down-regulation of two genes, ZMO0153 and ZMO0776, in SS3 suggesting potential genetic mechanisms behind SS3

  4. Effects of ultrasound and ultrasound assisted alkaline pretreatments on the enzymolysis and structural characteristics of rice protein.

    PubMed

    Li, Suyun; Yang, Xue; Zhang, Yanyan; Ma, Haile; Liang, Qiufang; Qu, Wenjuan; He, Ronghai; Zhou, Cunshan; Mahunu, Gustav Komla

    2016-07-01

    The objectives of this study were to investigate the effects of multi-frequency energy-gathered ultrasound (MFEGU) and MFEGU assisted alkaline pretreatments on the enzymolysis and the mechanism of two pretreatments accelerating the rice protein (RP) proteolysis process. The results showed that MFEGU and MFEGU assisted alkaline pretreatments improved significantly (P<0.05) the degree of hydrolysis (DH) and the protein elution amount of RP. Furthermore under the same DH conditions, ultrasound and ultrasound assisted alkaline pretreatments were more save the enzymolysis time than the unpretreatment. The changes in UV-vis spectra, fluorescence emission spectra indicated unfolding and destruction of RP by MFEGU and MFEGU assisted alkaline pretreatments. The circular dichroism analysis showed that both pretreatments decreased α-helix but increased β-sheet and random coil of RP. Amino acid composition revealed that MFEGU and MFEGU assisted alkaline pretreatments could increase the protein elution amount and the ratio of hydrophobic amino acids. Atomic force microscopy (AFM) indicated that both pretreatments destroyed the microstructures and reduced the particle size of RP. Therefore, MFEGU and MFEGU assisted alkaline pretreatments are beneficial to improving the degree of hydrolysis due to its sonochemistry effect on the molecular conformation as well as on the microstructure of protein. PMID:26964920

  5. Optimizing on-farm pretreatment of perennial grasses for fuel ethanol production.

    PubMed

    Digman, Matthew F; Shinners, Kevin J; Casler, Michael D; Dien, Bruce S; Hatfield, Ronald D; Jung, Hans-Joachim G; Muck, Richard E; Weimer, Paul J

    2010-07-01

    Switchgrass (Panicum virgatum L.) and reed canarygrass (Phalaris arundinacea L.) were pretreated under ambient temperature and pressure with sulfuric acid and calcium hydroxide in separate experiments. Chemical loadings from 0 to 100g (kg DM)(-1) and durations of anaerobic storage from 0 to 180days were investigated by way of a central composite design at two moisture contents (40% or 60% w.b.). Pretreated and untreated samples were fermented to ethanol by Saccharomyces cerevisiae D5A in the presence of a commercially available cellulase (Celluclast 1.5L) and beta-glucosidase (Novozyme 188). Xylose levels were also measured following fermentation because xylose is not metabolized by S. cerevisiae. After sulfuric acid pretreatment and anaerobic storage, conversion of cell wall glucose to ethanol for reed canarygrass ranged from 22% to 83% whereas switchgrass conversions ranged from 16% to 46%. Pretreatment duration had a positive effect on conversion but was mitigated with increased chemical loadings. Conversions after calcium hydroxide pretreatment and anaerobic storage ranged from 21% to 55% and 18% to 54% for reed canarygrass and switchgrass, respectively. The efficacy of lime pretreatment was found to be highly dependent on moisture content. Moreover, pretreatment duration was only found to be significant for reed canarygrass. Although significant levels of acetate and lactate were observed in the biomass after storage, S. cerevisiae was not found to be inhibited at a 10% solids loading. PMID:20202834

  6. Ultrastructural and cytochemical aspects of induced apogamy following abscisic acid pre-treatment of secondary moss protonema.

    PubMed

    Menon, M K; Bell, P R

    1981-05-01

    Abscisic acid (ABA) treatment of secondary protonema of Physcomitrium pyriforme Brid in the presence of sucrose does not prevent cell division but results in shorter cells with vesicular cytoplasm and an accumulation of lipid. When transferred to sucrose medium without ABA and with low irradiance isodiametric intercalary cells are cut off which give rise to apogamous sporophytes either directly or after the formation of a small amount of callus. The organization of the cells leading up to the apogamous sporophyte is described. The cells initiating the sporophyte develop dense cytoplasm and the walls become labyrinthine and callosed, but they do not form any recognizable placenta. It is proposed that labyrinthine walls are a consequence of a perturbation of cell wall metabolism as growth changes from gametophytic to sporophytic. The use of the term "transfer cell" for this kind of cell is questioned and the need for a causal approach to the investigation of labyrinthine walls is stressed. PMID:24302107

  7. Ecophysiological Significance of CO2-Recycling via Crassulacean Acid Metabolism in Talinum calycinum Engelm. (Portulacaceae) 1

    PubMed Central

    Martin, Craig E.; Higley, Michael; Wang, Wei-Zhong

    1988-01-01

    High levels of variability in gas exchange characteristics and degree of CAM-cycling were found in the same and different individuals of Talinum calycinum Engelm. collected from rock outcrops in Missouri. Differences in CO2 assimilation were mostly correlated with differences in shoot conductance to CO2 not shoot internal CO2 concentration. As found previously, CAM acid fluctuations were evident in well-watered plants exhibiting C3 gas exchange patterns (CAM-cycling) and also in drought-stressed plants with stomata closed, or nearly so, day and night (CAM-idling). Drought stress also resulted in rapid stomatal closure, conserving water during droughts. Maximal CO2 uptake rates occurred below 35°C; higher temperatures induced decreases in CO2 assimilation and conductance while shoot internal CO2 concentrations remained similar. Plant water-use-efficiency was severely curtailed at temperatures above 30°C. Tissue acid fluctuations were the result of changes in malic acid concentrations. Calculations of the amount of water potentially conserved by CAM-cycling yielded values of approximately 5 to 44% of daytime water loss. Thus, CAM-cycling may be an important adaptation minimizing water loss by perennial succulents growing in shallow soil on rock outcrops. PMID:16665946

  8. Pretreatment of dried distillers grains with solubles by soaking in aqueous ammonia and subsequent enzymatic/dilute acid hydrolysis to produce fermentable sugars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15% w/w NH4OH solution at a solid:liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied...

  9. Jasmonic acid accumulation and systemic photosynthetic and electrical changes in locally burned wild type tomato, ABA-deficient sitiens mutants and sitiens pre-treated by ABA.

    PubMed

    Hlavinka, Jan; Nožková-Hlaváčková, Vladimíra; Floková, Kristýna; Novák, Ondřej; Nauš, Jan

    2012-05-01

    Burning the terminal leaflet of younger tomato (Lycopersicon esculentum Mill.) leaf caused local and systemic changes in the surface electrical potential (SEP) and gas exchange (GE) parameters. The local and systemic accumulation of endogenous abscisic acid (ABA) and jasmonic acid (JA) was measured 85 min after burning. The experiments were conducted with wild type (WT) plants, ABA-deficient mutant sitiens (SIT) and ABA pre-treated SIT plants (SITA). First changes in SEP were detected within 1.5 min after burning and were followed by a decrease in GE parameters within 3-6 min in WT, SIT and SITA plants. GE and SEP time courses of SIT were different and wave amplitudes of SEP of SIT were lower compared to WT and SITA. ABA content in WT and SITA control plants was similar and substantially higher compared to SIT, JA content was similar among WT, SIT and SITA. While changes in the ABA content in systemic leaves have not been recorded after burning, the systemic JA content was substantially increased in WT and more in SIT and SITA. The results suggest that ABA content governs the systemic reaction of GE and the SEP shape upon local burning. ABA, JA and SEP participate in triggering the GE reaction. The ABA shortage in the SIT in the reaction to burning is partly compensated by an enhanced JA accumulation. This JA compensation is maintained even in SIT endogenously supplied with ABA. A correlation between the systemic JA content and changes in GE parameters or SEP was not found. PMID:22391126

  10. Glycyrrhizic acid pretreatment prevents sepsis-induced acute kidney injury via suppressing inflammation, apoptosis and oxidative stress.

    PubMed

    Zhao, Hongyu; Liu, Zhenning; Shen, Haitao; Jin, Shuai; Zhang, Shun

    2016-06-15

    Glycyrrhizic acid (GA), an active ingredient in licorice, has multiple pharmacological activities. The aim of our study was to investigate the molecular mechanism involved in the protective effects of GA in lipopolysaccharide (LPS) stimulated rat mesangial cells (HBZY-1) and septic rats. Sepsis model was established by injection of 5mg/kg LPS in rats or incubation with 1μg/ml LPS for 24h in HBZY-1 cells. A variety of molecular biological experiments were carried out to assess the effects of GA on inflammation, apoptosis, and oxidative stress. First we found that GA alleviated sepsis-induced kidney injury in vivo. Furthermore, GA suppressed inflammatory response in vivo and in vitro. Additionally, GA inhibited cell apoptosis and the changes in expressions of apoptosis related proteins induced by LPS. Moreover, GA markedly inhibited oxidative stress induced by LPS via activation of ERK signaling pathway. Finally GA could inhibit the activation of NF-κ B induced by LPS. Our present study indicates that GA has a protective effect against sepsis-induced inflammatory response, apoptosis, and oxidative stress damage, which provides a molecular basis for a new medical treatment of septic acute kidney injury. PMID:27063444

  11. Amylases without known homologues discovered in an acid mine drainage: significance and impact

    PubMed Central

    Delavat, François; Phalip, Vincent; Forster, Anne; Plewniak, Frédéric; Lett, Marie-Claire; Lièvremont, Didier

    2012-01-01

    Acid Mine Drainages (AMDs) are extreme environments characterized by acidic and oligotrophic conditions and by metal contaminations. A function-based screening of an AMD-derived metagenomic library led to the discovery and partial characterization of two non-homologous endo-acting amylases sharing no sequence similarity with any known amylase nor glycosidase. None carried known amylolytic domains, nor could be assigned to any GH-family. One amylase displayed no similarity with any known protein, whereas the second one was similar to TraC proteins involved in the bacterial type IV secretion system. According to the scarce similarities with known proteins, 3D-structure modelling using I-TASSER was unsuccessful. This study underlined the utility of a function-driven metagenomic approach to obtain a clearer image of the bacterial community enzymatic landscape. More generally, this work points out that screening for microorganisms or biomolecules in a priori incongruous environments could provide unconventional and new exciting ways for bioprospecting. PMID:22482035

  12. Significance of pH on the Cytotoxic Potential of the Water Disinfection By-Product Iodoacetic Acid

    EPA Science Inventory

    Significance of pH on the Cytotoxic Potential of the Water Disinfection By-Product Iodoacetic Acid Vicki Richardson1, Susan D. Richardson2, Mary Moyer3, Jane Ellen Simmons1, and Anthony DeAngelo1, 1U.S. Environmental Protection Agency, Research Triangle Park, NC, 2University of...

  13. Significantly enhancing supercapacitive performance of nitrogen-doped graphene nanosheet electrodes by phosphoric acid activation.

    PubMed

    Wang, Ping; He, Haili; Xu, Xiaolong; Jin, Yongdong

    2014-02-12

    In this work, we present a new method to synthesize the phosphorus, nitrogen contained graphene nanosheets, which uses dicyandiamide to prevent the aggregation of graphene oxide and act as the nitrogen precursor, and phosphoric acid (H3PO4) as the activation reagent. We have found that through the H3PO4 activation, the samples exhibit the remarkably enhanced supercapacitive performance, and depending on the amount of H3PO4 introduced, the specific capacitance of the samples is gradually increased from 7.6 to 244.6 F g(-1). Meanwhile, the samples also exhibit the good rate capability and excellent stability (up to 10 000 cycles). Through the transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller analyses, H3PO4 treatment induced large pore volume and phosphorus related function groups in the product are assumed to response for the enhancement. PMID:24456232

  14. Exogenous abscisic acid significantly affects proteome in tea plant (Camellia sinensis) exposed to drought stress

    PubMed Central

    Zhou, Lin; Xu, Hui; Mischke, Sue; Meinhardt, Lyndel W; Zhang, Dapeng; Zhu, Xujun; Li, Xinghui; Fang, Wanping

    2014-01-01

    Tea [Camellia sinensis (L.) O. Kuntze] is an important economic crop, and drought is the most important abiotic stress affecting yield and quality. Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance. Increased understanding of ABA effects on tea plant under drought stress is essential to develop drought-tolerant tea genotypes, along with crop management practices that can mitigate drought stress. The objective of the present investigation is evaluation of effects of exogenous ABA on the leaf proteome in tea plant exposed to drought stress. Leaf protein patterns of tea plants under simulated drought stress [(polyethylene glycol (PEG)-treated] and exogenous ABA treatment were analyzed in a time-course experiment using two-dimensional electrophoresis (2-DE), followed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Among the 72 protein spots identified by MALDI-TOF MS, 16 proteins were downregulated and two were upregulated by exogenous ABA. The upregulated proteins have roles in glycolysis and photosystem II stabilization. Twenty-one protein spots were responsive to drought stress and most participate in carbohydrate and nitrogen metabolism, control of reactive oxygen species (ROS), defense, signaling or nucleic acid metabolism. The combined treatments of exogenous ABA and drought showed upregulation of 10 protein spots at 12 h and upregulation of 11 proteins at 72 h after initiation of drought stress. The results support the importance of the role that ABA plays in the tea plant during drought stress, by improving protein transport, carbon metabolism and expression of resistance proteins. PMID:27076915

  15. Comparative efficiency of different pretreatment methods on enzymatic digestibility of Parthenium sp.

    PubMed

    Pandiyan, K; Tiwari, Rameshwar; Rana, Sarika; Arora, Anju; Singh, Surender; Saxena, Anil Kumar; Nain, Lata

    2014-01-01

    The potential of Parthenium sp. as a feedstock for enzymatic saccharification was investigated by using chemical and biological pretreatment methods. Mainly chemical pretreatments (acid and alkali) were compared with biological pretreatment with lignolytic fungi Marasmiellus palmivorus PK-27. Structural and chemical changes as well as crystallinity of cellulose were examined through scanning electron microscopy, fourier transform infra red and X-ray diffraction analysis, respectively after pretreatment. Total reducing sugar released during enzymatic saccharification of pretreated substrates was also evaluated. Among the pretreatment methods, alkali (1% NaOH) treated substrate showed high recovery of acid perceptible polymerised lignin (7.53 ± 0.5 mg/g) and significantly higher amount of reducing sugar (513.1 ± 41.0 mg/gds) compared to uninoculated Parthenium (163.4 ± 21.2) after 48 h of hydrolysis. This is the first report of lignolytic enzyme production from M. palmivorus, prevalent in oil palm plantations in Malaysia and its application in biological delignification of Parthenium sp. Alkali (1% NaOH) treatment proves to be the suitable method of pretreatment for lignin recovery and enhanced yield of reducing sugar which may be used for bioethanol production from Parthenium sp. PMID:23824667

  16. Biological Significance of Urolithins, the Gut Microbial Ellagic Acid-Derived Metabolites: The Evidence So Far

    PubMed Central

    Espín, Juan Carlos; Larrosa, Mar; García-Conesa, María Teresa; Tomás-Barberán, Francisco

    2013-01-01

    The health benefits attributed to pomegranate have been associated with its high content in polyphenols, particularly ellagitannins. This is also the case for other ellagitannin-containing fruits and nuts including strawberry, raspberry, blackberry, walnuts, and muscadine grapes. The bioavailability of ellagitannins and ellagic acid is however very low. These molecules suffer extensive metabolism by the gut microbiota to produce urolithins that are much better absorbed. Urolithins circulate in plasma as glucuronide and sulfate conjugates at concentrations in the range of 0.2–20 μM. It is therefore conceivable that the health effects of ellagitannin-containing products can be associated with these gut-produced urolithins, and thus the evaluation of the biological effects of these metabolites is essential. Recent research, mostly based on in vitro testing, has shown preliminary evidence of the anti-inflammatory, anticarcinogenic, antiglycative, antioxidant, and antimicrobial effects of urolithins, supporting their potential contribution to the health effects attributed to pomegranate and ellagitannin-rich foods. The number of in vivo studies is still limited, but they show preventive effects of urolithins on gut and systemic inflammation that encourage further research. Both in vivo and mechanistic studies are necessary to clarify the health effects of these metabolites. Attention should be paid when designing these mechanistic studies in order to use the physiologically relevant metabolites (urolithins in gut models and their conjugated derivatives in systemic models) at concentrations that can be reached in vivo. PMID:23781257

  17. Effect of dentin pretreatment and curing mode on the microtensile bond strength of self-adhesive resin cements

    PubMed Central

    Youm, Seung-Hyun; Jung, Kyoung-Hwa; Son, Sung-Ae; Kwon, Yong-Hoon

    2015-01-01

    PURPOSE The aim was to evaluate the effect of curing mode and different dentin surface pretreatment on microtensile bond strength (µTBS) of self-adhesive resin cements. MATERIALS AND METHODS Thirty-six extracted human permanent molars were sectioned horizontally exposing flat dentin surface. The teeth were divided into 12 groups (3 teeth/group) according to the dentin surface pretreatment methods (control, 18% EDTA, 10% Polyacrylic acid) and curing mode (self-curing vs. light-curing) of cement. After pretreatment, composite resin blocks were cemented with the following: (a) G-CEM LinkAce; (b) RelyX U200, followed by either self-curing or light-curing. After storage, the teeth were sectioned and µTBS test was performed using a microtensile testing machine. The data was statistically analyzed using one-way ANOVA, Student T-test and Scheffe's post-hoc test at P<.05 level. RESULTS For G-CEM LinkAce cement groups, polyacrylic acid pretreatment showed the highest µTBS in the self-cured group. In the light-cured group, no significant improvements were observed according to the dentin surface pretreatment. There were no significant differences between curing modes. Both dentin surface pretreatment methods helped to increase the µTBS of RelyX U200 resin cement significantly and degree of pretreatment effect was similar. No significant differences were found regarding curing modes except control groups. In the comparisons of two self-adhesive resin cements, all groups within the same pretreatment and curing mode were significantly different excluding self-cured control groups. CONCLUSION Selecting RelyX U200 used in this study and application of dentin surface pretreatment with EDTA and polyacrylic acid might be recommended to enhance the bond strength of cement to dentin. PMID:26330979

  18. Clinical significance of urinary liver-type fatty acid binding protein at various stages of nephropathy.

    PubMed

    Viswanathan, V; Sivakumar, S; Sekar, V; Umapathy, D; Kumpatla, S

    2015-01-01

    This cross-sectional study was to evaluate the levels of urinary liver-type fatty acid binding protein (u-LFABP pg/mg urine creatinine ratio) at different stages of diabetic nephropathy and to see its correlation with other clinical parameters in South Indian patients with type 2 diabetes mellitus (T2DM). A total of 65 (M: F; 42:23) T2DM subjects were divided into three groups, and were compared with 13 (M: F; 3:10) nondiabetic controls. The study groups were as follows: normoalbuminuric (n = 22), microalbuminuric (n = 22) and macroalbuminuric (n = 21). Estimated glomerular filtration rate (eGFR) was calculated using Cockcroft and Gault formula. u-LFABP levels in spot urine samples were measured with a solid phase enzyme linked immunosorbent assay. This study showed that u-LFABP levels were undetectable in healthy controls and was very low in the normoalbuminuric subjects. Elevated levels of u-LFABP are evident from the microalbuminuric stage indicating tubular damage. The levels of u-LFABP increased gradually with declining renal function. Geometric mean (95% confidence interval) for normoalbuminuria was 0.65 (0.47-0.97), microalbuminuria was 0.99 (0.55-1.97) and macroalbuminuria was 5.16 (1.8-14.5), (P = 0.005). In conclusion, u-LFABP levels were elevated in patients with reduced eGFR and showed a positive correlation with systolic blood pressure and protein to creatinine ratio in the total study subjects. PMID:26628791

  19. Clinical significance of urinary liver-type fatty acid binding protein at various stages of nephropathy

    PubMed Central

    Viswanathan, V.; Sivakumar, S.; Sekar, V.; Umapathy, D.; Kumpatla, S.

    2015-01-01

    This cross-sectional study was to evaluate the levels of urinary liver-type fatty acid binding protein (u-LFABP pg/mg urine creatinine ratio) at different stages of diabetic nephropathy and to see its correlation with other clinical parameters in South Indian patients with type 2 diabetes mellitus (T2DM). A total of 65 (M: F; 42:23) T2DM subjects were divided into three groups, and were compared with 13 (M: F; 3:10) nondiabetic controls. The study groups were as follows: normoalbuminuric (n = 22), microalbuminuric (n = 22) and macroalbuminuric (n = 21). Estimated glomerular filtration rate (eGFR) was calculated using Cockcroft and Gault formula. u-LFABP levels in spot urine samples were measured with a solid phase enzyme linked immunosorbent assay. This study showed that u-LFABP levels were undetectable in healthy controls and was very low in the normoalbuminuric subjects. Elevated levels of u-LFABP are evident from the microalbuminuric stage indicating tubular damage. The levels of u-LFABP increased gradually with declining renal function. Geometric mean (95% confidence interval) for normoalbuminuria was 0.65 (0.47–0.97), microalbuminuria was 0.99 (0.55–1.97) and macroalbuminuria was 5.16 (1.8–14.5), (P = 0.005). In conclusion, u-LFABP levels were elevated in patients with reduced eGFR and showed a positive correlation with systolic blood pressure and protein to creatinine ratio in the total study subjects. PMID:26628791

  20. Catabolism of Branched Chain Amino Acids Contributes Significantly to Synthesis of Odd-Chain and Even-Chain Fatty Acids in 3T3-L1 Adipocytes

    PubMed Central

    Crown, Scott B.; Marze, Nicholas; Antoniewicz, Maciek R.

    2015-01-01

    The branched chain amino acids (BCAA) valine, leucine and isoleucine have been implicated in a number of diseases including obesity, insulin resistance, and type 2 diabetes mellitus, although the mechanisms are still poorly understood. Adipose tissue plays an important role in BCAA homeostasis by actively metabolizing circulating BCAA. In this work, we have investigated the link between BCAA catabolism and fatty acid synthesis in 3T3-L1 adipocytes using parallel 13C-labeling experiments, mass spectrometry and model-based isotopomer data analysis. Specifically, we performed parallel labeling experiments with four fully 13C-labeled tracers, [U-13C]valine, [U-13C]leucine, [U-13C]isoleucine and [U-13C]glutamine. We measured mass isotopomer distributions of fatty acids and intracellular metabolites by GC-MS and analyzed the data using the isotopomer spectral analysis (ISA) framework. We demonstrate that 3T3-L1 adipocytes accumulate significant amounts of even chain length (C14:0, C16:0 and C18:0) and odd chain length (C15:0 and C17:0) fatty acids under standard cell culture conditions. Using a novel GC-MS method, we demonstrate that propionyl-CoA acts as the primer on fatty acid synthase for the production of odd chain fatty acids. BCAA contributed significantly to the production of all fatty acids. Leucine and isoleucine contributed at least 25% to lipogenic acetyl-CoA pool, and valine and isoleucine contributed 100% to lipogenic propionyl-CoA pool. Our results further suggest that low activity of methylmalonyl-CoA mutase and mass action kinetics of propionyl-CoA on fatty acid synthase result in high rates of odd chain fatty acid synthesis in 3T3-L1 cells. Overall, this work provides important new insights into the connection between BCAA catabolism and fatty acid synthesis in adipocytes and underscores the high capacity of adipocytes for metabolizing BCAA. PMID:26710334

  1. Improved enzymatic hydrolysis of wheat straw by combined use of gamma ray and dilute acid for bioethanol production

    NASA Astrophysics Data System (ADS)

    Hyun Hong, Sung; Taek Lee, Jae; Lee, Sungbeom; Gon Wi, Seung; Ju Cho, Eun; Singh, Sudhir; Sik Lee, Seung; Yeoup Chung, Byung

    2014-01-01

    Pretreating wheat straw with a combination of dilute acid and gamma irradiation was performed in an attempt to enhance the enzymatic hydrolysis for bioethanol production. The glucose yield was significantly affected by combined pretreatment (3% sulfuric acid-gamma irradiation), compared with untreated wheat straw and individual pretreatment. The increasing enzymatic hydrolysis after combined pretreatment is resulting from decrease in crystallinity of cellulose, loss of hemicelluloses, and removal or modification of lignin. Therefore, combined pretreatment is one of the most effective methods for enhancing the enzymatic hydrolysis of wheat straw biomass.

  2. Effect of anion structures on cholinium ionic liquids pretreatment of rice straw and the subsequent enzymatic hydrolysis.

    PubMed

    Hou, Xue-Dan; Xu, Jie; Li, Ning; Zong, Min-Hua

    2015-01-01

    In this work, 28 cholinium ionic liquids (ILs), most of which are good solvents for dissolving lignin, were used for rice straw pretreatment to improve subsequent enzymatic hydrolysis. The anion exerted a significant effect on the pretreatment effectiveness of the IL as well as the subsequent enzymatic hydrolysis efficiency of rice straw residues. The presence of the basic group(s) in the anion significantly enhanced the IL pretreatment effectiveness, while the carboxyl, hydroxyl and aromatic groups had a negative impact on IL delignification. Except for amino acid-based ILs, the delignification abilities of the ILs are linearly and positively correlated with the pKa values of the conjugate acids of the anions. Of the ILs tested, amino acid-based ILs, especially basic amino acid-based ILs, are the most effective pretreatment solvents. Satisfactory reducing sugar yields (81% for glucose and 26% for xylose) were obtained in the enzymatic hydrolysis of rice straw pretreated by cholinium argininate ([Ch][Arg]) under a pretty mild pretreatment severity (60°C, 6 h). The results presented in this work may be useful for rational design of novel and green ILs for delignification of lignocellulose. PMID:25067792

  3. 4-O-Acetyl-sialic acid (Neu4,5Ac2) in acidic milk oligosaccharides of the platypus (Ornithorhynchus anatinus) and its evolutionary significance.

    PubMed

    Urashima, Tadasu; Inamori, Hiroaki; Fukuda, Kenji; Saito, Tadao; Messer, Michael; Oftedal, Olav T

    2015-06-01

    Monotremes (echidnas and platypus) retain an ancestral form of reproduction: egg-laying followed by secretion of milk onto skin and hair in a mammary patch, in the absence of nipples. Offspring are highly immature at hatching and depend on oligosaccharide-rich milk for many months. The primary saccharide in long-beaked echidna milk is an acidic trisaccharide Neu4,5Ac2(α2-3)Gal(β1-4)Glc (4-O-acetyl 3'-sialyllactose), but acidic oligosaccharides have not been characterized in platypus milk. In this study, acidic oligosaccharides purified from the carbohydrate fraction of platypus milk were characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and (1)H-nuclear magnetic resonance spectroscopy. All identified structures, except Neu5Ac(α2-3)Gal(β1-4)Glc (3'-sialyllactose) contained Neu4,5Ac2 (4-O-acetyl-sialic acid). These include the trisaccharide 4-O-acetyl 3'-sialyllactose, the pentasaccharide Neu4,5Ac2(α2-3)Gal(β1-4)GlcNAc(β1-3)Gal(β1-4)Glc (4-O-acetyl-3'-sialyllacto-N-tetraose d) and the hexasaccharide Neu4,5Ac2(α2-3)Gal(β1-4)[Fuc(α1-3)]GlcNAc(β1-3)Gal(β1-4)Glc (4-O-acetyl-3'-sialyllacto-N-fucopentaose III). At least seven different octa- to deca-oligosaccharides each contained a lacto-N-neohexaose core (LNnH) and one or two Neu4,5Ac2 and one to three fucose residues. We conclude that platypus milk contains a diverse (≥ 20) array of neutral and acidic oligosaccharides based primarily on lactose, lacto-N-neotetraose (LNnT) and LNnH structural cores and shares with echidna milk the unique feature that all identified acidic oligosaccharides (other than 3'-sialyllactose) contain the 4-O-acetyl-sialic acid moiety. We propose that 4-O-acetylation of sialic acid moieties protects acidic milk oligosaccharides secreted onto integumental surfaces from bacterial hydrolysis via steric interference with bacterial sialidases. This may be of evolutionary significance since taxa ancestral to monotremes and other mammals are

  4. Cost Effective Bioethanol via Acid Pretreatment of Corn Stover, Saccharification, and Conversion via a Novel Fermentation Organism: Cooperative Research and Development Final Report, CRADA Number: CRD-12-485

    SciTech Connect

    Dowe, N.

    2014-05-01

    This research program will convert acid pretreated corn stover to sugars at the National Renewable Energy Laboratory (NREL) and then transfer these sugars to Honda R&D and its partner the Green Earth Institute (GEI) for conversion to ethanol via a novel fermentation organism. In phase one, NREL will adapt its pretreatment and saccharification process to the unique attributes of this organism, and Honda R&D/GEI will increase the sugar conversion rate as well as the yield and titer of the resulting ethanol. In later phases, NREL, Honda R&D, and GEI will work together at NREL to optimize and scale-up to pilot-scale the Honda R&D/GEI bioethanol production process. The final stage will be to undertake a pilot-scale test at NREL of the optimized bioethanol conversion process.

  5. Value added liquid products from waste biomass pyrolysis using pretreatments.

    PubMed

    Das, Oisik; Sarmah, Ajit K

    2015-12-15

    Douglas fir wood, a forestry waste, was attempted to be converted into value added products by pretreatments followed by pyrolysis. Four different types of pretreatments were employed, namely, hot water treatment, torrefaction, sulphuric acid and ammonium phosphate doping. Subsequently, pyrolysis was done at 500°C and the resulting bio-oils were analysed for their chemical composition using Karl Fischer titration, thermogravimetry, ion exchange, and gas chromatography. Pretreatment with acid resulted in the highest yield of bio-oil (~60%). The acid and salt pretreatments were responsible for drastic reduction in the lignin oligomers and enhancement of water content in the pyrolytic liquid. The quantity of xylose/mannose reduced as a result of pretreatments. Although, the content of fermentable sugars remained similar across all the pretreatments, the yield of levoglucosan increased. Pretreatment of the biomass with acid yielded the highest amount of levoglucosan in the bio-oil (13.21%). The acid and salt pretreatments also elevated the amount of acetic acid in the bio-oils. Addition of acid and salt to the biomass altered the interaction of cellulose-lignin in the pyrolysis regime. Application of pretreatments should be based on the intended end use of the liquid product having a desired chemical composition. PMID:26298257

  6. De novo Fatty Acid Biosynthesis Contributes Significantly to Establishment of a Bioenergetically Favorable Environment for Vaccinia Virus Infection

    PubMed Central

    Greseth, Matthew D.; Traktman, Paula

    2014-01-01

    The poxvirus life cycle, although physically autonomous from the host nucleus, is nevertheless dependent upon cellular functions. A requirement for de novo fatty acid biosynthesis was implied by our previous demonstration that cerulenin, a fatty acid synthase inhibitor, impaired vaccinia virus production. Here we show that additional inhibitors of this pathway, TOFA and C75, reduce viral yield significantly, with partial rescue provided by exogenous palmitate, the pathway's end-product. Palmitate's major role during infection is not for phospholipid synthesis or protein palmitoylation. Instead, the mitochondrial import and β-oxidation of palmitate are essential, as shown by the impact of etomoxir and trimetazidine, which target these two processes respectively. Moreover, the impact of these inhibitors is exacerbated in the absence of exogenous glucose, which is otherwise dispensable for infection. In contrast to glucose, glutamine is essential for productive viral infection, providing intermediates that sustain the TCA cycle (anaplerosis). Cumulatively, these data suggest that productive infection requires the mitochondrial β-oxidation of palmitate which drives the TCA cycle and energy production. Additionally, infection causes a significant rise in the cellular oxygen consumption rate (ATP synthesis) that is ablated by etomoxir. The biochemical progression of the vaccinia life cycle is not impaired in the presence of TOFA, C75, or etomoxir, although the levels of viral DNA and proteins synthesized are somewhat diminished. However, by reversibly arresting infections at the onset of morphogenesis, and then monitoring virus production after release of the block, we determined that virion assembly is highly sensitive to TOFA and C75. Electron microscopic analysis of cells released into C75 revealed fragmented aggregates of viroplasm which failed to be enclosed by developing virion membranes. Taken together, these data indicate that vaccinia infection, and in

  7. De novo fatty acid biosynthesis contributes significantly to establishment of a bioenergetically favorable environment for vaccinia virus infection.

    PubMed

    Greseth, Matthew D; Traktman, Paula

    2014-03-01

    The poxvirus life cycle, although physically autonomous from the host nucleus, is nevertheless dependent upon cellular functions. A requirement for de novo fatty acid biosynthesis was implied by our previous demonstration that cerulenin, a fatty acid synthase inhibitor, impaired vaccinia virus production. Here we show that additional inhibitors of this pathway, TOFA and C75, reduce viral yield significantly, with partial rescue provided by exogenous palmitate, the pathway's end-product. Palmitate's major role during infection is not for phospholipid synthesis or protein palmitoylation. Instead, the mitochondrial import and β-oxidation of palmitate are essential, as shown by the impact of etomoxir and trimetazidine, which target these two processes respectively. Moreover, the impact of these inhibitors is exacerbated in the absence of exogenous glucose, which is otherwise dispensable for infection. In contrast to glucose, glutamine is essential for productive viral infection, providing intermediates that sustain the TCA cycle (anaplerosis). Cumulatively, these data suggest that productive infection requires the mitochondrial β-oxidation of palmitate which drives the TCA cycle and energy production. Additionally, infection causes a significant rise in the cellular oxygen consumption rate (ATP synthesis) that is ablated by etomoxir. The biochemical progression of the vaccinia life cycle is not impaired in the presence of TOFA, C75, or etomoxir, although the levels of viral DNA and proteins synthesized are somewhat diminished. However, by reversibly arresting infections at the onset of morphogenesis, and then monitoring virus production after release of the block, we determined that virion assembly is highly sensitive to TOFA and C75. Electron microscopic analysis of cells released into C75 revealed fragmented aggregates of viroplasm which failed to be enclosed by developing virion membranes. Taken together, these data indicate that vaccinia infection, and in

  8. Down-regulation of crambe fatty acid desaturase and elongase in Arabidopsis and crambe resulted in significantly increased oleic acid content in seed oil.

    PubMed

    Li, Xueyuan; Mei, Desheng; Liu, Qing; Fan, Jing; Singh, Surinder; Green, Allan; Zhou, Xue-Rong; Zhu, Li-Hua

    2016-01-01

    High oleic oil is an important industrial feedstock that has been one of the main targets for oil improvement in a number of oil crops. Crambe (Crambe abyssinica) is a dedicated oilseed crop, suitable for industrial oil production. In this study, we down-regulated the crambe fatty acid desaturase (FAD) and fatty acid elongase (FAE) genes for creating high oleic seed oil. We first cloned the crambe CaFAD2, CaFAD3 and CaFAE1 genes. Multiple copies of each of these genes were isolated, and the highly homologous sequences were used to make RNAi constructs. These constructs were first tested in Arabidopsis, which led to the elevated oleic or linoleic levels depending on the genes targeted, indicating that the RNAi constructs were effective in regulating the expression of the target genes in nonidentical but closely related species. Furthermore, down-regulation of CaFAD2 and CaFAE1 in crambe with the FAD2-FAE1 RNAi vector resulted in even more significant increase in oleic acid level in the seed oil with up to 80% compared to 13% for wild type. The high oleic trait has been stable in subsequent five generations and the GM line grew normally in greenhouse. This work has demonstrated the great potential of producing high oleic oil in crambe, thus contributing to its development into an oil crop platform for industrial oil production. PMID:25998013

  9. Comparison of bond strength and surface morphology of dental enamel for acid and Nd-YAG laser etching

    NASA Astrophysics Data System (ADS)

    Parmeswearan, Diagaradjane; Ganesan, Singaravelu; Ratna, P.; Koteeswaran, D.

    1999-05-01

    Recently, laser pretreatment of dental enamel has emerged as a new technique in the field of orthodontics. However, the changes in the morphology of the enamel surface is very much dependent on the wavelength of laser, emission mode of the laser, energy density, exposure time and the nature of the substance absorbing the energy. Based on these, we made a comparative in vitro study on laser etching with acid etching with reference to their bond strength. Studies were conducted on 90 freshly extracted, non carious, human maxillary or mandibular anteriors and premolars. Out of 90, 60 were randomly selected for laser irradiation. The other 30 were used for conventional acid pretreatment. The group of 60 were subjected to Nd-YAG laser exposure (1060 nm, 10 Hz) at differetn fluences. The remaining 30 were acid pretreated with 30% orthophosphoric acid. Suitable Begg's brackets were selected and bound to the pretreated surface and the bond strength were tested using Instron testing machine. The bond strength achieved through acid pretreatment is found to be appreciably greater than the laser pretreated tooth. Though the bond strength achieved through the acid pretreated tooth is found to be significantly greater than the laser pretreated specimens, the laser pretreatement is found to be successful enough to produce a clinically acceptable bond strength of > 0.60 Kb/mm. Examination of the laser pre-treated tooth under SEM showed globule formation which may produce the mechanical interface required for the retention of the resin material.

  10. 40 CFR 417.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... treatment works must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.146 Pretreatment standards for new sources. Any...

  11. 40 CFR 417.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... treatment works must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.146 Pretreatment standards for new sources. Any...

  12. 40 CFR 417.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... treatment works must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.146 Pretreatment standards for new sources. Any...

  13. 40 CFR 417.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... treatment works must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.146 Pretreatment standards for new sources. Any...

  14. 40 CFR 417.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... treatment works must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Neutralization of Sulfuric Acid Esters and Sulfonic Acids Subcategory § 417.146 Pretreatment standards for new sources. Any...

  15. Clinical significance of elevated serum A-FABP and free fatty acid in neonates with hypoxic ischemic brain damage

    PubMed Central

    Li, Mei; Jiang, Lian; Zhang, Huifen; Wang, Dandan; Zhang, Min; Zhang, Lianshan

    2016-01-01

    The main function of adipocyte fatty acid-binding protein (A-FABP) is to regulate fatty acid metabolism as its molecular chaperone. The clinical significance of A-FABP in hypoxic-ischemic brain damage (HIBD) neonates is not yet clear. Free fatty acid (FFA) in cerebral cortex increases along with hypoxia ischemia degree. Thus, we aimed to investigate whether FFA can induce A-FABP expression and elevate the serum A-FABP level in HIBD neonates. In the present study, 42 HIBD neonates were selected including 11 cases as mild, 16 cases as moderate and 15 cases as severe. The serum was collected from peripheral vein at 72 h after the first visit (acute stage) and 7 days after birth (recovery stage), and the serum from 10 normal neonates was used as the control. The serum level of A-FABP and FFA in 42 neonates with acute phase and recovery phase HIBD were detected using ELISA and copper colorimetric method. The overall serum A-FABP content in HIBD neonates at the acute stage was significantly higher compared to the normal neonates (P<0.05). The serum A-FABP level in severe HIBD neonates was significantly higher than that in mild HIBD, moderate HIBD and normal neonates (P<0.05). The serum FFA level in HIBD neonates at the acute stage was 1,521.57±605.63 µmol/l, which was significantly higher than that in the normal neonates 838.24±294.22 µmol/l. The serum FFA levels in mild, moderate and severe HIBD neonates were significantly higher than those in the normal neonates. The overall A-FABP level in HIBD neonates at the recovery stage was significantly lower compared to the acute stage, which was significant in severe HIBD neonates. A-FABP levels in mild and moderate HIBD neonates at recovery stage were decreased compared with the acute stage, although there was no statistical difference. There was a positive correlation between serum A-FABP and FFA in HIBD neonates at acute stage (r=0.369, P<0.05). In conclusion, serum A-FABP and FFA levels were signifcantly increased in

  16. Autohydrolysis Pretreatment of Lignocellulosic Biomass for Bioethanol Production

    NASA Astrophysics Data System (ADS)

    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

  17. Method for pretreating lignocellulosic biomass

    SciTech Connect

    Kuzhiyil, Najeeb M.; Brown, Robert C.; Dalluge, Dustin Lee

    2015-08-18

    The present invention relates to a method for pretreating lignocellulosic biomass containing alkali and/or alkaline earth metal (AAEM). The method comprises providing a lignocellulosic biomass containing AAEM; determining the amount of the AAEM present in the lignocellulosic biomass; identifying, based on said determining, the amount of a mineral acid sufficient to completely convert the AAEM in the lignocellulosic biomass to thermally-stable, catalytically-inert salts; and treating the lignocellulosic biomass with the identified amount of the mineral acid, wherein the treated lignocellulosic biomass contains thermally-stable, catalytically inert AAEM salts.

  18. The Impact of Post-Pretreatment Conditioning on Enzyme Accessibility and Water Interactions in Alkali Pretreated Rice Straw

    NASA Astrophysics Data System (ADS)

    Karuna, Nardrapee

    Rice straw, a high-abundance lignocellulosic residue from rice production has tremendous potential as a feedstock for biofuel production in California. In this study, the impact of post-alkali pretreatment conditioning schemes on enzyme saccharification efficiency was examined, particularly focusing on understanding resulting biomass compositional impacts on water interactions with the biomass and enzyme accessibility to the cellulose fraction. Rice straw was pretreated with sodium hydroxide and subsequently washed by two different conditions: 1) by extensive washing with distilled water to reduce the pH to the optimum for cellulases which is pH 5--6, and 2) immediate pH adjustment to pH 5--6 with hydrochloric acid before extensive washing with distilled water. The two post-pretreatment conditions gave significant differences in ash, acid-insoluble lignin, glucan and xylan compositions. Alkali pretreatment improved cellulase digestibility of rice straw, and water washing improved enzymatic digestibility more than neutralization. Hydrolysis reactions with a purified Trichoderma reesei Cel7A, a reducing-end specific cellulase, demonstrated that the differences in saccharification are likely due to differences in the accessibility of the cellulose fraction to the cellulolytic enzymes. Further analyses were conducted to study the mobility of the water associated with the rice straw samples by measuring T2 relaxation times of the water protons by 1H-Nuclear Magnetic Resonance (NMR) relaxometry. Results showed significant changes in water association with the rice straw due to the pretreatment and due to the two different post-pretreatment conditions. Pretreatment increased the amount of water at the surface of the rice straw samples as indicated by increased amplitude of the shortest T2 time peaks in the relaxation spectra. Moreover, the amount of water in the first T2 pool in the water washed sample was significantly greater than in the neutralized sample. These

  19. Steam cooking significantly improves in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage.

    PubMed

    Kahlon, Talwinder Singh; Chiu, Mei-Chen M; Chapman, Mary H

    2008-06-01

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowered recirculation of bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increased risk of cancer. Bile acid binding potential has been related to lowering the risk of heart disease and that of cancer. Previously, we have reported bile acid binding by several uncooked vegetables. However, most vegetables are consumed after cooking. How cooking would influence in vitro bile acid binding of various vegetables was investigated using a mixture of bile acids secreted in human bile under physiological conditions. Eight replicate incubations were conducted for each treatment simulating gastric and intestinal digestion, which included a substrate only, a bile acid mixture only, and 6 with substrate and bile acid mixture. Cholestyramine (a cholesterol-lowering, bile acid binding drug) was the positive control treatment and cellulose was the negative control. Relative to cholestyramine, in vitro bile acid binding on dry matter basis was for the collard greens, kale, and mustard greens, 13%; broccoli, 10%; Brussels sprouts and spinach, 8%; green bell pepper, 7%; and cabbage, 5%. These results point to the significantly different (P < or = .05) health-promoting potential of collard greens = kale = mustard greens > broccoli > Brussels sprouts = spinach = green bell pepper > cabbage as indicated by their bile acid binding on dry matter basis. Steam cooking significantly improved the in vitro bile acid binding of collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage compared with previously observed bile acid binding values for these vegetables raw (uncooked). Inclusion of steam-cooked collard greens, kale, mustard greens, broccoli, green bell pepper, and cabbage in our daily diet as health-promoting vegetables should be emphasized. These green

  20. Haplotypes of the D-Amino Acid Oxidase Gene Are Significantly Associated with Schizophrenia and Its Neurocognitive Deficits

    PubMed Central

    Hwu, Hai-Gwo; Fann, Cathy Shen-Jang; Yang, Ueng-Cheng; Yang, Wei-Chih; Hsu, Pei-Chun; Chang, Chien-Ching; Wen, Chun-Chiang; Tsai-Wu, Jyy-Jih; Hwang, Tzung-Jeng; Hsieh, Ming H.; Liu, Chen-Chung; Chien, Yi-Ling; Fang, Chiu-Ping; Faraone, Stephen V.; Tsuang, Ming T.; Chen, Wei J.; Liu, Chih-Min

    2016-01-01

    D-amino acid oxidase (DAO) has been reported to be associated with schizophrenia. This study aimed to search for genetic variants associated with this gene. The genomic regions of all exons, highly conserved regions of introns, and promoters of this gene were sequenced. Potentially meaningful single-nucleotide polymorphisms (SNPs) obtained from direct sequencing were selected for genotyping in 600 controls and 912 patients with schizophrenia and in a replicated sample consisting of 388 patients with schizophrenia. Genetic associations were examined using single-locus and haplotype association analyses. In single-locus analyses, the frequency of the C allele of a novel SNP rs55944529 located at intron 8 was found to be significantly higher in the original large patient sample (p = 0.016). This allele was associated with a higher level of DAO mRNA expression in the Epstein-Barr virus-transformed lymphocytes. The haplotype distribution of a haplotype block composed of rs11114083-rs2070586-rs2070587-rs55944529 across intron 1 and intron 8 was significantly different between the patients and controls and the haplotype frequencies of AAGC were significantly higher in patients, in both the original (corrected p < 0.0001) and replicated samples (corrected p = 0.0003). The CGTC haplotype was specifically associated with the subgroup with deficits in sustained attention and executive function and the AAGC haplotype was associated with the subgroup without such deficits. The DAO gene was a susceptibility gene for schizophrenia and the genomic region between intron 1 and intron 8 may harbor functional genetic variants, which may influence the mRNA expression of DAO and neurocognitive functions in schizophrenia. PMID:26986737

  1. Solids Control in Sludge Pretreatment

    SciTech Connect

    Beahm, E.C., Weber, C.F., Hunt, R.D., Dillow, T.A.

    1997-12-31

    Sludge pretreatment will likely involve washing, followed by caustic or acidic leaching and washing of sludge residues after leaching. The principal goal of pretreatment is to obtain a low-volume high-activity waste stream and a high-volume low-activity waste stream. Also, some waste constituents such as chromium and phosphate can be included in glass formulations only at very low concentrations; therefore, it is desirable to remove them from high-level waste streams. Two aspects of sludge treatment and subsequent separations should be well delineated and predictable: (1) the distribution of chemical species between aqueous solutions and solids and (2) potential problems due to chemical interactions that could result in process difficulties or safety concerns.Before any treatment technology is adopted, it must be demonstrated that the process can be carried out as planned. Three pretreatment methods were considered in the Tri-Party (Washington State Ecology, U.S. Environmental Protection Agency, and U.S. Department of Energy) negotiations: (1) sludge washing with corrosion- inhibiting water, (2) Enhanced Sludge Washing, and (3)acidic dissolution with separations processes. Enhanced Sludge Washing is the baseline process. In Enhanced Sludge Washing, sludge is first washed with corrosion-inhibiting water; it is then leached with caustic (sodium hydroxide solution) and washed again with corrosion- inhibiting water. The initial concern is whether a pretreatment technique is effective in separating sludge components. This can be evaluated by bench-scale tests with sludge specimens from underground storage tanks. The results give data on the distribution of important species such as aluminum, phosphate, and radionuclides between wash and leach solutions and solid sludge residues.

  2. Production of high optical purity l-lactic acid from waste activated sludge by supplementing carbohydrate: effect of temperature and pretreatment time.

    PubMed

    Jian, Qiwei; Li, Xiang; Chen, Yinguang; Liu, Yanan; Pan, Yin

    2016-10-01

    It has been widely accepted that the most environmentally beneficial way to treat waste activated sludge (WAS), the byproduct of municipal wastewater treatment plant, is to recover the valuable organic acid. However, the bio-conversion of lactic acid, one of the high added-value chemical, is seldom reported from WAS fermentation. In this paper, l-lactic acid was observed dominant in the WAS fermentation liquid with carbohydrate addition at ambient temperature. Furthermore, the effect of temperature on l-lactic acid and d-lactic acid production was fully discussed: two isomers were rapidly produced and consumed up in one day at mesophilic condition; and almost optically pure l-lactic acid was generated at thermophilic condition, yet time-consuming with yield of l-lactic acid enhancing by 52.9% compared to that at ambient temperature. The study mechanism showed that mesophilic condition was optimal for both production and consumption of l-lactic acid and d-lactic acid, while consumption of l-lactic acid and production of d-lactic acid were severely inhibited at thermophilic condition. Therefore, by maintaining thermophilic for 4 h in advance and subsequently fermenting mesophilic for 34 h, the concentration of l-lactic acid with optical activity of 98.3% was improved to 16.6 ± 0.5 g COD/L at a high specific efficiency of 0.6097/d. PMID:26878176

  3. ECLSS Sustaining Compatibility Testing on Urine Processor Assembly Nonmetallic Materials for Reformulation of Pretreated Urine Solution

    NASA Technical Reports Server (NTRS)

    Wingard, C. D.

    2015-01-01

    On International Space Station (ISS), the Urine Processor Assembly (UPA) converts human urine and flush water into potable water. The urine is acid-pretreated primarily to control microbial growth. In recent years, the sulfuric acid (H2SO4) pretreatment was believed to be largely responsible for producing salt crystals capable of plugging filters in UPA components and significantly reducing the percentage of water recovery from urine. In 2012, ISS management decided to change the acid pretreatment for urine from sulfuric to phosphoric with the goal of eliminating or minimizing formation of salt crystals. In 2013-2014, as part of the qualification of the phosphoric acid (H3PO4) formulation, samples of 12 nonmetallic materials used in UPA components were immersed for up to one year in pretreated urine and brine solutions made with the new H3PO4 formulation. Dynamic mechanical analysis (DMA) was used to measure modulus (stiffness) of the immersed samples compared to virgin control samples. Such compatibility data obtained by DMA for the H3PO4-based solutions were compared to DMA data obtained for the H2SO4-based solutions in 2002-2003.

  4. Lignocellulose pretreatment severity - relating pH to biomatrix opening.

    PubMed

    Pedersen, Mads; Meyer, Anne S

    2010-12-31

    In cellulose-to-ethanol processes a physico-chemical pretreatment of the lignocellulosic feedstock is a crucial prerequisite for increasing the amenability of the cellulose to enzymatic attack. Currently published pretreatment strategies span over a wide range of reaction conditions involving different pH values, temperatures, types of catalysts and holding times. The consequences of the pretreatment on lignocellulosic biomass are described with special emphasis on the chemical alterations of the biomass during pretreatment, especially highlighting the significance of the pretreatment pH. We present a new illustration of the pretreatment effects encompassing the differential responses to the pH and temperature. A detailed evaluation of the use of severity factor calculations for pretreatment comparisons signifies that the multiple effects of different pretreatment factors on the subsequent monosaccharide yields after enzymatic hydrolysis cannot be reliably compared by a one-dimensional severity factor, even within the same type of pretreatment strategy. However, a quantitative comparison of published data for wheat straw pretreatment illustrates that there is some correlation between the hydrolysis yields (glucose and xylose) and the pretreatment pH, but no correlation with the pretreatment temperature (90-200°C). A better recognition and understanding of the factors affecting biomatrix opening, and use of more standardized evaluation protocols, will allow for the identification of new pretreatment strategies that improve biomass utilization and permit rational enzymatic hydrolysis of the cellulose. PMID:20460178

  5. Fermentation of dilute acid pretreated Populus by Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis

    SciTech Connect

    Yee, Kelsey L.; Rodriguez, Jr., Miguel; Hamilton, Choo Yieng; Hamilton-Brehm, Scott D.; Thompson, Olivia A.; Elkins, James G.; Davison, Brian H.; Mielenz, Jonathan R.

    2015-07-25

    Consolidated bioprocessing (CBP), which merges enzyme production, biomass hydrolysis, and fermentation into a single step, has the potential to become an efficient and economic strategy for the bioconversion of lignocellulosic feedstocks to transportation fuels or chemicals. In this study, we evaluated Clostridium thermocellum, Caldicellulosiruptor bescii, and Caldicellulosiruptor obsidiansis, three , thermophilic,cellulolytic, mixed-acid fermenting candidate CBP microorganisms, for their fermentation capabilities using dilute acid pretreated Populus as a model biomass feedstock. Under pH controlled, anaerobic fermentation conditions, each candidate successfully digested a minimum of 75% of the cellulose from dilute acid pretreated Populus, as indicated by an increase in planktonic cells and end-product metabolites and a concurrent decrease in glucan content. C. thermocellum, which employs a cellulosomal approach to biomass degradation, required 120 hours to achieve 75% cellulose utilization. In contrast, the non-cellulosomal, secreted hydrolytic enzyme system of the Caldicellulosiruptor sp. required 300 hours to achieve similar results. End-point fermentation conversions for C. thermocellum, C. bescii, and C. obsidiansis were determined to be 0.29, 0.34, and 0.38 grams of total metabolites per gram of loaded glucan, respectively. This data provide a starting point for future strain engineering efforts that can serve to improve the biomass fermentation capabilities of these three promising candidate CBP platforms.

  6. Lignocellulosic Biomass Pretreatment: A Key to Its Successful Bioconversion to Fuel Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Native lignocellulosic biomass is very resistant to degradation by enzymes. Prior pretreatment is essential for efficient conversion of lignocellulosic feedstock to ethanol. In this presentation, various pretreatment options such as dilute acid, alkali, alkaline peroxide, wet oxidation, steam expl...

  7. Application of a slurry feeder to 1 and 3 stage continuous simultaneous saccharification and fermentation of dilute acid pretreated corn stover.

    PubMed

    Brethauer, Simone; Studer, Michael H; Wyman, Charles E

    2014-10-01

    Continuous operation is often chosen for conceptual designs of biological processing of cellulosic biomass to ethanol to achieve higher volumetric productivities. Furthermore, continuous stirred tank reactors (CSTR) can handle higher solids concentrations than possible in batch mode due to broth thinning at partial conversion in a continuous fermentor. However, experience and literature data are very limited for continuous simultaneous saccharification and fermentation (cSSF) processes. In this work, a slurry feed system was developed and applied to a 3-stage bench-scale cSSF train to convert pretreated corn stover to ethanol and determine the effects of dilution rate and number of fermentation vessels on overall volumetric productivity. The highest productivity of 0.4gL(-1)h(-1) was achieved in a single cSSF vessel with an 8h residence time. Furthermore, productivity at identical total residence times was 12% higher for operation with 3 cSSF stages than for a single CSTR stage for pretreated corn stover. PMID:25164339

  8. An evaluation of the significance of mouth and hand contamination for lead absorption in lead-acid battery workers.

    PubMed

    Far, H S; Pin, N T; Kong, C Y; Fong, K S; Kian, C W; Yan, C K

    1993-01-01

    The present study was conducted to evaluate the role of ingestion through hand and mouth contamination in the absorption of lead in 25 lead-acid battery workers. Levels of personal exposure to airborne lead ranged from 0.004 to 2.58 mg/m3 [geometric mean 0.098, with 25% of samples exceeding threshold limit values (ACGIH) of 0.15 mg/m3]; the mean (SD) blood lead level was 48.9 (10.8) micrograms/dl. Mean hand lead contents increased 33-fold from preshift levels on Monday mornings (33.5 micrograms/500 ml) to midshift levels on Thursday afternoons (1121 micrograms/500 ml). Mouth lead contents increased 16-fold from 0.021 micrograms/50 ml on Mondays to 0.345 micrograms/50 ml on Thursdays. The typical Malay racial habit of feeding with bare hands and fingers without utensils (closely associated with mouth and hand lead levels on Mondays) explained the bulk of the variance in blood lead levels (40%), with mouth lead on Thursdays (closely associated with poor personal hygiene) explaining a further 10%. Air lead was not a significant explanatory variable. The implementation of a programme of reinforcing hand-washing and mouth-rinsing practices resulted in a reduction of the blood lead level by 11.5% 6 months later. These results indicate that parenteral intake from hand and mouth contamination is an important cause of lead absorption in lead-exposed workers. PMID:8458660

  9. Bioinspired syntheses of dimeric hydroxycinnamic acids (lignans) and hybrids, using phenol oxidative coupling as key reaction, and medicinal significance thereof.

    PubMed

    Magoulas, George E; Papaioannou, Dionissios

    2014-01-01

    Lignans are mainly dimers of 4-hydroxycinnamic acids (HCAs) and reduced analogs thereof which are produced in Nature through phenol oxidative coupling (POC) as the primary C-C or C-O bond-forming reaction under the action of the enzymes peroxidases and laccases. They present a large structural variety and particularly interesting biological activities, therefore, significant efforts has been devoted to the development of efficient methodologies for the synthesis of lignans isolated from natural sources, analogs and hybrids with other biologically interesting small molecules. We summarize in the present review those methods which mimic Nature for the assembly of the most common lignan skeleta by using either enzymes or one-electron inorganic oxidants to effect POC of HCAs and derivatives, such as esters and amides, or cross-POC of pairs of HCAs or HCAs with 4-hydrocycinnamyl alcohols. We, furthermore, provide outlines of mechanistic schemes accounting for the formation of the coupled products and, where applicable, indicate their potential application in medicine. PMID:25460307

  10. Cellulosic biomass pretreatment and sugar yields as a function of biomass particle size.

    PubMed

    Dougherty, Michael J; Tran, Huu M; Stavila, Vitalie; Knierim, Bernhard; George, Anthe; Auer, Manfred; Adams, Paul D; Hadi, Masood Z

    2014-01-01

    Three lignocellulosic pretreatment techniques (ammonia fiber expansion, dilute acid and ionic liquid) are compared with respect to saccharification efficiency, particle size and biomass composition. In particular, the effects of switchgrass particle size (32-200) on each pretreatment regime are examined. Physical properties of untreated and pretreated samples are characterized using crystallinity, surface accessibility measurements and scanning electron microscopy (SEM) imaging. At every particle size tested, ionic liquid (IL) pretreatment results in greater cell wall disruption, reduced crystallinity, increased accessible surface area, and higher saccharification efficiencies compared with dilute acid and AFEX pretreatments. The advantages of using IL pretreatment are greatest at larger particle sizes (>75 µm). PMID:24971883

  11. Cellulosic Biomass Pretreatment and Sugar Yields as a Function of Biomass Particle Size

    PubMed Central

    Stavila, Vitalie; Knierim, Bernhard; George, Anthe; Auer, Manfred; Adams, Paul D.; Hadi, Masood Z.

    2014-01-01

    Three lignocellulosic pretreatment techniques (ammonia fiber expansion, dilute acid and ionic liquid) are compared with respect to saccharification efficiency, particle size and biomass composition. In particular, the effects of switchgrass particle size (32–200) on each pretreatment regime are examined. Physical properties of untreated and pretreated samples are characterized using crystallinity, surface accessibility measurements and scanning electron microscopy (SEM) imaging. At every particle size tested, ionic liquid (IL) pretreatment results in greater cell wall disruption, reduced crystallinity, increased accessible surface area, and higher saccharification efficiencies compared with dilute acid and AFEX pretreatments. The advantages of using IL pretreatment are greatest at larger particle sizes (>75 µm). PMID:24971883

  12. Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

    DOEpatents

    Francis, Raymond

    2012-11-06

    Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

  13. High-titer lactic acid production from NaOH-pretreated corn stover by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile condition.

    PubMed

    Hu, Jinlong; Zhang, Zhenting; Lin, Yanxu; Zhao, Shumiao; Mei, Yuxia; Liang, Yunxiang; Peng, Nan

    2015-04-01

    Lactic acid (LA) is an important chemical with various industrial applications. Non-food feedstock is commercially attractive for use in LA production; however, efficient LA fermentation from lignocellulosic biomass resulting in both high yield and titer faces technical obstacles. In this study, the thermophilic bacterium Bacillus coagulans LA204 demonstrated considerable ability to ferment glucose, xylose, and cellobiose to LA. Importantly, LA204 produces LA from several NaOH-pretreated agro stovers, with remarkably high yields through simultaneous saccharification and fermentation (SSF). A fed-batch SSF process conducted at 50°C and pH 6.0, using a cellulase concentration of 30 FPU (filter paper unit)/g stover and 10 g/L yeast extract in a 5-L bioreactor, was developed to produce LA from 14.4% (w/w) NaOH-pretreated non-sterile corn stover. LA titer, yield, and average productivity reached 97.59 g/L, 0.68 g/g stover, and 1.63 g/L/h, respectively. This study presents a feasible process for lignocellulosic LA production from abundant agro stovers. PMID:25704098

  14. Pretreatment of microbial sludges

    DOEpatents

    Rivard, Christopher J.; Nagle, Nicholas J.

    1995-01-01

    Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

  15. Pretreatment of microbial sludges

    DOEpatents

    Rivard, C.J.; Nagle, N.J.

    1995-01-10

    Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

  16. Steam Cooking Significantly Improves in Vitro Bile Acid Binding of Beets, Eggplant, Asparagus, Carrots, Green Beans and Cauliflower

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The relative healthful potential of cooked beets, okra, eggplant, asparagus, carrots, green beans, cauliflower and turnips was evaluated by determining their in vitro bile acid binding using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two...

  17. Structural modifications of lignocellulosics by pretreatments to enhance enzymatic hydrolysis

    SciTech Connect

    Gharpuray, M.M.; Lee, Y.F.; Fan, L.T.

    1983-01-01

    In this work an evaluation was made of a wide variety of single and multiple pretreatment methods for enhancing the rate of enzymatic hydrolysis of wheat straw. A multiple pretreatment consisted of a physical pretreatment followed by a chemical pretreatment. The structural features of wheat straw, including the specific surface area, crystallinity index, and lignin content, were measured to understand the mechanism of the enhancement in the hyrolysis rate upon pretreatment. It has been found that, in general, multiple pretreatments were not promising, since the hydrolysis rates rarely exceeded those achieved by single pretreatments. Ball-milling pretreatment was found to be effective in increasing the specific surface area and decreasing the crystallinity index. Treatment with ethylene glycol was highly effective in increasing the specific surface area, in addition to a high degree of delignification. Peracetic acid pretreatment was highly effective in delignifying substrate. Among multiple pretreatments, those involving peracetic acid treatment generally had lower crystallinity indices and lignin content values. The relationship between the hydrolysis rate and the set of structural features indicated that an increase in surface area and a decrease in the crystallinity and lignin content enhance the hydrolysis; the specific surface area is the most influential of the structural features, followed by the lignin content. (Refs. 23).

  18. Enhanced L-lysine production from pretreated beet molasses by engineered Escherichia coli in fed-batch fermentation.

    PubMed

    He, Xun; Chen, Kequan; Li, Yan; Wang, Zhen; Zhang, Hong; Qian, Juan; Ouyang, Pingkai

    2015-08-01

    Faster sugar consumption rate and low-cost nitrogen source are required for the chemical biosynthesis using molasses. Five pretreatment methods were applied to beet molasses prior to fermentation through engineered Escherichia coli, respectively, and corn steep liquid was used as an organic nitrogen source to replace expensive yeast extract. Furthermore, the effects of different feeding strategy in fed-batch fermentation on L-lysine production were investigated. The experimental results showed that combined tricalcium phosphate, sulfuric acid, and activated carbon pretreatment method (TPSA) pretreatment could improve the sugar consumption rate most greatly, and the initial total sugar concentration of 35 g/L from TPSA-pretreated beet molasses gave the best results with respect to L-lysine production, dry cell weight concentration, and L-lysine yield in batch fermentation. Moreover, a mixture of low-cost corn steep liquid and yeast extract containing equal amount of nitrogen could be used as the organic nitrogen source for effective L-lysine fermentation, and constant speed feeding strategy of TPSA-pretreated beet molasses promoted L-lysine production by engineered E. coli. The TPSA-pretreated beet molasses had a sugar consumption rate of 1.75 g/(L h), and a L-lysine yield of 27.81% was achieved, compared with the theoretical yield of 62% by glucose. It was clarified that the pretreatment significantly enhanced the conversion of sugars in beet molasses to L-lysine. PMID:25899726

  19. An effective pre-treatment method for the determination of short-chain fatty acids in a complex matrix by derivatization coupled with headspace single-drop microextraction.

    PubMed

    Chen, Yuan; Li, Yun; Xiong, Yongqiang; Fang, Chenchen; Wang, Xiaotao

    2014-01-17

    We have developed a sample preparation method involving derivatization combined with headspace single-drop microextraction (HS-SDME) for the determination of short-chain fatty acids (SCFAs) in complex matrices. The derivatization of SCFAs was conducted using the BF3/ethanol method prior to HS-SDME. The HS-SDME extraction conditions for the derivatization products (ethyl esters) of SCFAs were optimized using 1.0μL of dibutylphthalate (DBP), 1000rpm stirring speed, 30% (w/v) NaCl, 20min extraction time, and 7mL of sample solution in a 12mL vial. Quantitative determination of ethyl esters was performed using gas chromatography (GC). Linear calibration curves and excellent reproducibility were obtained using these optimized extraction conditions. Compared with our previous work, the significantly lower detection limits (0.11, 0.017, 0.0060, and 0.0024μg/mL for C2 to C5 SCFAs, respectively) indicate that this new method is suitable for quantitative analysis of SCFAs in complex matrices, such as the RuO4 oxidation products of kerogen or asphaltene. PMID:24388413

  20. [THE DETECTION OF CONTENT OF DIAGNOSTICALLY SIGNIFICANT FATTY ACIDS AND INDIVIDUAL TRIGLYCERIDES IN BIOLOGICAL MEDIUMS BASED ON INFRARED SPECTROMETRY].

    PubMed

    Kalinin, A V; Krasheninnikov, V N; Sviridov, A P; Titov, V N

    2015-11-01

    The content of clinically important fatty acids and individual triglycerides in food and biological mediums are traditionally detected by gas and fluid chromatography in various methodical modifications. The techniques are hard-to-get in laboratories of clinical biochemistry. The study was carried out to develop procedures and equipment for operative quantitative detection of concentration of fatty acids, primarily palmitic saturated fatty acid and oleic mono unsaturated fatty acid. Also detection was applied to sums ofpolyenoic (eicosapentaenoic and docosahexaenoic acid) fatty acids in biological mediums (cod-liver oil, tissues, blood plasma) using spectrometers of short-range infrared band of different types: with Fourier transform, diffraction and combined scattering. The evidences of reliable and reproducible quantitative detection offatty acids were received on the basis of technique of calibration (regression) by projection on latent structures using standard samples of mixtures of oils and fats. The evaluation is implemented concerning possibility of separate detection of content of palmitic and oleic triglycerides in mediums with presence of water The choice of technical conditions and mode of application of certain types of infrared spectrometers and techniques of their calibration is substantiated PMID:26999859

  1. Hydrolytic pretreatment of softwood and almond shells. Degree of polymerization and enzymatic digestibility of the cellulose fraction

    SciTech Connect

    Martinez, J.M.; Reguant, J.; Montero, M.A.; Montane, D.; Salvado, J.; Farriol, X.

    1997-03-01

    Autohydrolysis and dilute-acid hydrolysis were used as pretreatment methods to enhance the enzymatic digestibility of cellulose in two different lignocellulosic substrates, a softwood mixture and an agricultural residue of almond shells. The changes in the chemical composition of the softwood mixture during dilute-acid pretreatment were studied, and the results were grouped by using a severity parameter, KR{sub OH}, which was derived from the kinetics of hemicellulose solubilization. The average degree of polymerization of the cellulose retained in the pretreated substrate, DP{sub v}, was investigated and its trend compared with that of almond shells. Cellulose DP{sub v} decreased for both the substrates from a value of 700 for the untreated lignocellulosic to around 200, which corresponds to the leveling-off degree of polymerization, as there is no significant variation in DP{sub v} when severity increases. Glucose yields after enzymatic saccharification of the pretreated substrates turned out to be higher for almond shells than for the softwood mixture, which had a very low susceptibility to enzymatic hydrolysis throughout the spectrum of experimental conditions investigated. At KR{sub OH} = 15,000, the glucose yield for the softwood mixture is 44% of the potential fraction present in the pretreated pulp, while for almond shells the maximum yield surpasses 97% for KR{sub OH} = 3. The different behavior these lignocellulosic species is not caused by different degrees of cellulose depolymerization nor by the removal of different amounts of carbohydrates during pretreatments in equivalent conditions.

  2. Efficiency of single stage- and two stage pretreatment in biomass with different lignin content.

    PubMed

    Kärcher, M A; Iqbal, Y; Lewandowski, I; Senn, T

    2016-07-01

    In current study the enzymatic glucose yields of miscanthus and wheat straw were compared after single stage- and two stage pretreatment with dilute sulfuric acid at different pretreatment severities. Glucose yields after two stage pretreatment were higher than after single stage pretreatment in miscanthus. Whereas wheat straw had higher glucose yields after single stage pretreatment. The study shows that two stage pretreatment has a negative effect on glucose yield in biomass with low not-acid-degradable lignin content and a positive one in biomass with high not-acid-degradable lignin content. The not-acid-degradable lignin fraction offers a higher degree of protection of the whole lignin structure against chemical attacks by mineral acids. More severe pretreatment conditions were needed to achieve a sufficient breakup of the lignin structure. But more severe conditions enhance resin formation, leading to lower enzyme activity and reduced carbohydrate yields. PMID:27067673

  3. Significance of amino acid variation at human immunodeficiency virus type 1 reverse transcriptase residue 210 for zidovudine susceptibility.

    PubMed Central

    Harrigan, P R; Kinghorn, I; Bloor, S; Kemp, S D; Nájera, I; Kohli, A; Larder, B A

    1996-01-01

    Amino acid variation at reverse transcriptase (RT) codon 210 (generally Leu-210 to Trp [L210W], TTG-->TGG) is occasionally detected after the initiation of azidothymidine (AZT) therapy. The impact of this variation on AZT resistance and viral replication was addressed by four different approaches. The frequency and genetic background of the L210W mutation in vivo were assessed by analyzing sera of AZT-naive and AZT-experienced patients by RT-PCR and DNA sequencing. The degree of AZT resistance (50% infective concentration [IC50]) of recombinant viruses constructed by using the RT of 21 clinical isolates was stratified by the presence or absence of the 210 mutation. The AZT IC50S of a panel of mutant viruses (with or without W-210) constructed by site-directed mutagenesis in an HXB2 background were assayed by using a HeLa CD4 plaque reduction assay. Finally, the effect of the 210 mutation on viral replication was assessed by replication competition of an AZT-resistant virus, RTMN (L-41/Y-215), and RTMN with the W-210 mutation in the presence and in the absence of AZT. In AZT-naive patients, tryptophan at RT residue 210 was rare. After AZT exposure, W-210 appeared in a minority of those patients, most commonly in association with L-41 and Y-215. The presence of W-210 increased the AZTIC50 by two- to fourfold, as determined by both the recombinant virus assay and site-directed mutagenesis. A significant replication advantage in favor of the wild-type L-210 over W-210 was observed, although the selection against the 210 mutant was two- to threefold lower when the viruses were grown in the presence of 5 microM AZT. In summary, the L210W mutation appears to be of marginal significance, conferring approximately two- to fourfold-reduced sensitivity to AZT compared with similar AZT-resistant genomes with L-210. The selection pressure against W-210 may account for the modest proportion of patients in which W-210 appears in vivo. PMID:8709214

  4. Enzymatic pretreatment for preparing starch nanocrystals.

    PubMed

    LeCorre, Déborah; Vahanian, Elina; Dufresne, Alain; Bras, Julien

    2012-01-01

    Starch nanocrystals (SNCs) are crystalline platelets resulting from the acid hydrolysis of starch. A limiting factor for their more widespread use is their preparation duration. Therefore, this study investigates the possibility of developing an enzymatic pretreatment of starch to reduce the acid hydrolysis duration. A screening of three types of enzymes, namely, α-amylase, β-amylase, and glucoamylase, is proposed, and the latter was selected for a pretreatment. Compared with the regular kinetics of hydrolysis for preparing SNC, that of pretreated starch was much faster. The extent of hydrolysis normally reached in 24 h was obtained after only 6 h, and the regular final yield (15% after 5 days) was reached in 45 h. AFM and X-ray diffraction measurements confirmed that the obtained nanoparticles were indeed SNC. PMID:22133316

  5. Ethanol production from acid- and alkali-pretreated corncob by endoglucanase and β-glucosidase co-expressing Saccharomyces cerevisiae subject to the expression of heterologous genes and nutrition added.

    PubMed

    Feng, Chunying; Zou, Shaolan; Liu, Cheng; Yang, Huajun; Zhang, Kun; Ma, Yuanyuan; Hong, Jiefang; Zhang, Minhua

    2016-05-01

    Low-cost technologies to overcome the recalcitrance of cellulose are the key to widespread utilization of lignocellulosic biomass for ethanol production. Efficient enzymatic hydrolysis of cellulose requires the synergism of various cellulases, and the ratios of each cellulase are required to be regulated to achieve the maximum hydrolysis. On the other hand, engineering of cellulolytic Saccharomyces cerevisiae strains is a promising strategy for lignocellulosic ethanol production. The expression of cellulase-encoding genes in yeast would affect the synergism of cellulases and thus the fermentation ability of strains with exogenous enzyme addition. However, such researches are rarely reported. In this study, ten endoglucanase and β-glucosidase co-expressing S. cerevisiae strains were constructed and evaluated by enzyme assay and fermentation performance measurement. The results showed that: (1) maximum ethanol titers of recombinant strains exhibited high variability in YPSC medium (20 g/l peptone, 10 g/l yeast extract, 100 g/l acid- and alkali-pretreated corncob) within 10 days. However, they had relatively little difference in USC medium (100 g/l acid- and alkali-pretreated corncob, 0.33 g/l urea, pH 5.0). (2) Strains 17# and 19#, with ratio (CMCase to β-glucosidase) of 7.04 ± 0.61 and 7.40 ± 0.71 respectively, had the highest fermentation performance in YPSC. However, strains 11# and 3# with the highest titers in USC medium had a higher ratio of CMCase to β-glucosidase, and CMCase activities. These results indicated that nutrition, enzyme activities and the ratio of heterologous enzymes had notable influence on the fermentation ability of cellulase-expressing yeast. PMID:27038956

  6. Effect of dark pretreatment on the kinetics of response of barley pulvini to gravistimulation and hormones

    NASA Technical Reports Server (NTRS)

    Brock, T. G.; Kaufman, P. B.

    1988-01-01

    Starch in pulvinus amyloplasts of barley (Hordeum vulgare cv Larker) disappears when 45-day-old, light-grown plants are given 5 days of continuous darkness. The effect of this loss on the pulvinus graviresponse was evaluated by following changes in the kinetics of response during the 5-day dark period. Over 5 days of dark pretreatment, the lag to initial graviresponse and the subsequent half-time to maximum steady state bending rate increased significantly while the maximum bending rate did not change. The change in response to applied indoleacetic acid (100 micromolar) plus gibberellic acid (10 micromolar) without gravistimulation, under identical dark pretreatments, was used as a model system for the response component of gravitropism. Dark pretreatment did not change the lag to initial response following hormone application to vertical pulvini, but both the maximum bending rate and the half-time to the maximum rate were significantly reduced. Also, after dark pretreatment, significant bending responses following hormone application were observed in vertical segments with or without added sucrose, while gravistimulation produced a response only if segments were given sucrose. These results indicate that starch-filled amyloplasts are required for the graviresponse of barley pulvini and suggest that they function in the stimulus perception and signal transduction components of gravitropism.

  7. 40 CFR 421.95 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for existing sources. The mass of wastewater pollutants in metallurgical acid plant...

  8. 40 CFR 421.95 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment... pounds) of 100 pct sulfuric acid capacity Cadmium 0.511 0.204 Zinc 2.605 1.073...

  9. 40 CFR 421.96 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Subcategory § 421.96 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new... comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... day Maximum for monthly average mg/kg (pounds per million pounds) of 100 pct sulfuric acid...

  10. 40 CFR 421.96 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Metallurgical Acid Plants Subcategory § 421.96 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new... comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass...

  11. 40 CFR 421.295 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Subcategory § 421.295 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403... treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for... (c) Tin mud acid neutralization filtrate. PSES for the Secondary Tin Subcategory Pollutant...

  12. 40 CFR 421.295 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Subcategory § 421.295 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403... treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for... (c) Tin mud acid neutralization filtrate. PSES for the Secondary Tin Subcategory Pollutant...

  13. 40 CFR 421.295 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Subcategory § 421.295 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403... treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for... (c) Tin mud acid neutralization filtrate. PSES for the Secondary Tin Subcategory Pollutant...

  14. 40 CFR 421.295 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Subcategory § 421.295 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403... treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for... (c) Tin mud acid neutralization filtrate. PSES for the Secondary Tin Subcategory Pollutant...

  15. 40 CFR 421.295 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Subcategory § 421.295 Pretreatment standards for existing sources. Except as provided in 40 CFR 403.7 and 403... treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for... (c) Tin mud acid neutralization filtrate. PSES for the Secondary Tin Subcategory Pollutant...

  16. 40 CFR 421.95 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment... pounds) of 100 pct sulfuric acid capacity Cadmium 0.511 0.204 Zinc 2.605 1.073...

  17. 40 CFR 421.95 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment... pounds) of 100 pct sulfuric acid capacity Cadmium 0.511 0.204 Zinc 2.605 1.073...

  18. 40 CFR 421.95 - Pretreatment standards for existing sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Plants Subcategory § 421.95 Pretreatment standards for existing sources. Except as provided in 40 CFR 403... publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment... pounds) of 100 pct sulfuric acid capacity Cadmium 0.511 0.204 Zinc 2.605 1.073...

  19. 40 CFR 421.96 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Subcategory § 421.96 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new... comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of....390 50.820 Molybdenum 1 . 1 For Molybdenum acid plants only....

  20. 40 CFR 421.96 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Subcategory § 421.96 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new... comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of....390 50.820 Molybdenum 1 . 1 For Molybdenum acid plants only....

  1. Comparison of some new pretreatment methods for second generation bioethanol production from wheat straw and water hyacinth.

    PubMed

    Guragain, Yadhu Nath; De Coninck, Joelle; Husson, Florence; Durand, Alain; Rakshit, Sudip Kumar

    2011-03-01

    Pretreatment of lignocellulosic residues like water hyacinth (WH) and wheat straw (WS) using crude glycerol (CG) and ionic liquids (IL) pretreatment was evaluated and compared with conventional dilute acid pretreatment (DAT) in terms of enzymatic hydrolysis yield and fermentation yield of pretreated samples. In the case of WS, 1-butyl-3-methylimidazolium acetate pretreatment was found to be the best method. The hydrolysis yields of glucose and total reducing sugars were 2.1 and 3.3 times respectively higher by IL pretreatment than DAT, while it was 1.4 and 1.9 times respectively higher with CG pretreatment. For WH sample, CG pretreatment was as effective as DAT and more effective than IL pretreatment regarding hydrolysis yield. The fermentation inhibition was not noticeable with both types of pretreatment methods and feedstocks. Besides, CG pretreatment was found as effective as pure glycerol pretreatment for both feedstocks. This opens up an attractive economic route for the utilization of CG. PMID:21273061

  2. Thermo-Acidic Pretreatment of Beach Macroalgae from Rügen to Optimize Biomethane Production—Double Benefit with Simultaneous Bioenergy Production and Improvement of Local Beach and Waste Management

    PubMed Central

    Barbot, Yann Nicolas; Thomsen, Laurenz; Benz, Roland

    2015-01-01

    Eutrophication is a phenomenon which can rapidly generate masses of marine macroalgae, particularly in areas with high nutrient pollution. Washed ashore, this biomass impairs coastal tourism and negatively affects the coastal ecosystem. The present study evaluates the biochemical methane potential (BMP) of a macroalgae mix (Rügen-Mix, RM (RM = Rügen-Mix)) originating from Rügen, Germany. To improve biomethane recovery, thermo-acidic pretreatment was applied to the biomass prior to biomethanation to disintegrate the biomass macrostructure. Acid hydrolysis was successfully triggered with 0.2 M industry-grade HCl at 80 °C for a 2 h period, increasing biomethane recovery by +39%, with a maximum BMP of 121 mL·g−1 volatile solids (VS). To reduce the necessity for input material, HCl was replaced by the acidic waste product flue gas condensate (FGC). Improved performance was achieved by showing an increase in biomethane recovery of +24% and a maximum BMP of 108 mL·g−1 VS. Continuous anaerobic digestion trials of RM were conducted for three hydraulic retention times, showing the feasibility of monodigestion. The biomethane recovery was 60 mL and 65 mL·g−1 VS·d−1 for thermophilic and mesophilic operation, respectively. The quality of biomethanation performance aligned to the composition of the source material which exhibited a low carbon/nitrogen ratio and an increased concentration of sulfur compounds. PMID:26404327

  3. Thermo-Acidic Pretreatment of Beach Macroalgae from Rügen to Optimize Biomethane Production--Double Benefit with Simultaneous Bioenergy Production and Improvement of Local Beach and Waste Management.

    PubMed

    Barbot, Yann Nicolas; Thomsen, Laurenz; Benz, Roland

    2015-09-01

    Eutrophication is a phenomenon which can rapidly generate masses of marine macroalgae, particularly in areas with high nutrient pollution. Washed ashore, this biomass impairs coastal tourism and negatively affects the coastal ecosystem. The present study evaluates the biochemical methane potential (BMP) of a macroalgae mix (Rügen-Mix, RM (RM = Rügen-Mix)) originating from Rügen, Germany. To improve biomethane recovery, thermo-acidic pretreatment was applied to the biomass prior to biomethanation to disintegrate the biomass macrostructure. Acid hydrolysis was successfully triggered with 0.2 M industry-grade HCl at 80 °C for a 2 h period, increasing biomethane recovery by +39%, with a maximum BMP of 121 mL·g(-1) volatile solids (VS). To reduce the necessity for input material, HCl was replaced by the acidic waste product flue gas condensate (FGC). Improved performance was achieved by showing an increase in biomethane recovery of +24% and a maximum BMP of 108 mL·g(-1) VS. Continuous anaerobic digestion trials of RM were conducted for three hydraulic retention times, showing the feasibility of monodigestion. The biomethane recovery was 60 mL and 65 mL·g(-1) VS·d(-1) for thermophilic and mesophilic operation, respectively. The quality of biomethanation performance aligned to the composition of the source material which exhibited a low carbon/nitrogen ratio and an increased concentration of sulfur compounds. PMID:26404327

  4. Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth

    PubMed Central

    Kianimanesh, Nasrin; Shayeghi, Bahareh

    2014-01-01

    Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application. PMID:25110641

  5. Oxidized and nitrated oleic acid in biological systems: analysis by GC-MS/MS and LC-MS/MS, and biological significance.

    PubMed

    Tsikas, Dimitrios; Zoerner, Alexander A; Jordan, Jens

    2011-11-01

    Compared to the arachidonic acid (C20:4) cascade, the oleic acid (C18:1) family comprises a handful known metabolites. The pathophysiology of oleic acid and its oxidized and nitrated metabolites, i.e., cis-9,10-epoxyoctadecanoic acid (cis-EpOA) and the two vinylic nitro-oleic acids cis-9-nitro-oleic acid (9-NO(2)-OA) and cis-10-nitro-oleic acid (10-NO(2)-OA), is only little investigated and little understood. cis-EpOA, 9-NO(2)-OA and 10-NO(2)-OA have been detected in plasma of healthy and ill human subjects by means of gas chromatography-tandem mass spectrometry (GC-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques in their acid and esterified forms. cis-EpOA is formed from oleic acid by the catalytic action of various cytochrome P450 isozymes. In end-stage liver disease, cis-EpOA plasma concentration is lower than in healthy subjects suggesting liver as the main organ responsible for cis-EpOA synthesis. The origin of 9-NO(2)-OA and 10-NO(2)-OA and of other nitrated oleic acid metabolites is unknown. In vitro models, nitro-oleic acid species can be formed non-enzymatically from oleic acid and nitrogen dioxide. Thus, endogenous nitro-oleic acids could serve as biomarkers of fatty acid nitration by reactive nitrogen species. Synthetic 9-NO(2)-OA and 10-NO(2)-OA at concentrations of three orders of magnitude higher than their endogenous counterparts have interesting pharmacological features and are currently intensely investigated. The present article reviews and discusses currently available analytical methods for the quantitative determination of cis-EpOA, 9-NO(2)-OA and 10-NO(2)-OA in biological samples, notably in human plasma, and the potential biological significance of these oleic acid metabolites. Special emphasis is given to GC-MS/MS and LC-MS/MS methods utilizing the stable-isotope dilution technique. The sensitivity and specificity of the MS/MS approach make electron-capture negative ion chemical ionization (ECNICI) GC

  6. Fundamental studies of water pretreatment of coal

    SciTech Connect

    Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S.; Bassilakis, R.

    1990-01-01

    The goals of this project are to gain understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. For the achievement of these goals, coals, modified coals and model-polymers will be treated with water or stream. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g. acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases of GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment. 1 ref., 2 figs., 1 tab.

  7. Fundamental studies of water pretreatment of coal

    SciTech Connect

    Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S.; Bassilakis, R.

    1990-01-01

    The goals of this project are to gain understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. Coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g. acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment. 3 figs., 3 tabs.

  8. Fundamental studies of water pretreatment of coal

    SciTech Connect

    Serio, M.A.; Kroo, E.; Solomon, P.R.; Charpenay, S.; Bassilakis, R.

    1991-01-01

    The goals of this project are to gain an understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. For the achievement of these goals, coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g., acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment.

  9. Pretreatment and Enzymatic Hydrolysis

    SciTech Connect

    2006-06-01

    Activities in this project are aimed at overcoming barriers associated with high capital and operating costs and sub-optimal sugar yields resulting from pretreatment and subsequent enzymatic hydrolysis of biomass.

  10. In situ detoxification of dry dilute acid pretreated corn stover by co-culture of xylose-utilizing and inhibitor-tolerant Saccharomyces cerevisiae increases ethanol production.

    PubMed

    Zhu, Jia-Qing; Li, Xia; Qin, Lei; Li, Wen-Chao; Li, Hui-Ze; Li, Bing-Zhi; Yuan, Ying-Jin

    2016-10-01

    Co-culture of xylose-utilizing and inhibitor-tolerant Saccharomyces cerevisiae was developed for bioethanol production from undetoxified pretreated biomass in simultaneously saccharification and co-fermentation (SSCF) process. Glucose accumulation during late fermentation phase in SSCF using xylose-utilizing strain can be eliminated by the introduction of inhibitor-tolerant strain. Effect of different ratios of two strains was investigated and xylose-utilizing strain to inhibitor-tolerant strain ratio of 10:1 (w/w) showed the best xylose consumption and the highest ethanol yield. Inoculating of xylose-utilizing strain at the later stage of SSCF (24-48h) exhibited lower ethanol yield than inoculating at early stage (the beginning 0-12h), probably due to the reduced enzymatic efficiency caused by the unconsumed xylose and oligomeric sugars. Co-culture SSCF increased ethanol concentration by 21.2% and 41.0% comparing to SSCF using individual inhibitor-tolerant and xylose-utilizing strain (increased from 48.5 and 41.7g/L to 58.8g/L), respectively, which suggest this co-culture system was very promising. PMID:27387414

  11. NREL 2012 Achievement of Ethanol Cost Targets: Biochemical Ethanol Fermentation via Dilute-Acid Pretreatment and Enzymatic Hydrolysis of Corn Stover

    SciTech Connect

    Tao, L.; Schell, D.; Davis, R.; Tan, E.; Elander, R.; Bratis, A.

    2014-04-01

    For the DOE Bioenergy Technologies Office, the annual State of Technology (SOT) assessment is an essential activity for quantifying the benefits of biochemical platform research. This assessment has historically allowed the impact of research progress achieved through targeted Bioenergy Technologies Office funding to be quantified in terms of economic improvements within the context of a fully integrated cellulosic ethanol production process. As such, progress toward the ultimate 2012 goal of demonstrating cost-competitive cellulosic ethanol technology can be tracked. With an assumed feedstock cost for corn stover of $58.50/ton this target has historically been set at $1.41/gal ethanol for conversion costs only (exclusive of feedstock) and $2.15/gal total production cost (inclusive of feedstock) or minimum ethanol selling price (MESP). This year, fully integrated cellulosic ethanol production data generated by National Renewable Energy Laboratory (NREL) researchers in their Integrated Biorefinery Research Facility (IBRF) successfully demonstrated performance commensurate with both the FY 2012 SOT MESP target of $2.15/gal (2007$, $58.50/ton feedstock cost) and the conversion target of $1.41/gal through core research and process improvements in pretreatment, enzymatic hydrolysis, and fermentation.

  12. 40 CFR 417.36 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Soap Manufacturing by Fatty Acid Neutralization Subcategory § 417.36 Pretreatment standards for new sources. Any new source...

  13. 40 CFR 417.36 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... must comply with 40 CFR part 403. ... GUIDELINES AND STANDARDS SOAP AND DETERGENT MANUFACTURING POINT SOURCE CATEGORY Soap Manufacturing by Fatty Acid Neutralization Subcategory § 417.36 Pretreatment standards for new sources. Any new source...

  14. Integrated analysis of hydrothermal flow through pretreatment

    PubMed Central

    2012-01-01

    Background The impact of hydrothermal flowthrough (FT) pretreatment severity on pretreatment and solubilization performance metrics was evaluated for three milled feedstocks (corn stover, bagasse, and poplar) and two conversion systems (simultaneous saccharification and fermentation using yeast and fungal cellulase, and fermentation by Clostridium thermocellum). Results Compared to batch pretreatment, FT pretreatment consistently resulted in higher XMG recovery, higher removal of non-carbohydrate carbon and higher glucan solubilization by simultaneous saccharification and fermentation (SSF). XMG recovery was above 90% for FT pretreatment below 4.1 severity but decreased at higher severities, particularly for bagasse. Removal of non-carbohydrate carbon during FT pretreatment increased from 65% at low severity to 80% at high severity for corn stover, and from 40% to 70% for bagasse and poplar. Solids obtained by FT pretreatment were amenable to high conversion for all of the feedstocks and conversion systems examined. The optimal time and temperature for FT pretreatment on poplar were found to be 16 min and 210°C. At these conditions, SSF glucan conversion was about 85%, 94% of the XMG was removed, and 62% of the non carbohydrate mass was solubilized. Solubilization of FT-pretreated poplar was compared for C. thermocellum fermentation (10% inoculum), and for yeast-fungal cellulase SSF (5% inoculum, cellulase loading of 5 and 10 FPU/g glucan supplemented with β-glucosidase at 15 and 30 U/g glucan). Under the conditions tested, which featured low solids concentration, C. thermocellum fermentation achieved faster rates and more complete conversion of FT-pretreated poplar than did SSF. Compared to SSF, solubilization by C. thermocellum was 30% higher after 4 days, and was over twice as fast on ball-milled FT-pretreated poplar. Conclusions XMG removal trends were similar between feedstocks whereas glucan conversion trends were significantly different, suggesting that

  15. Reduced gastric acid production in burn shock period and its significance in the prevention and treatment of acute gastric mucosal lesions.

    PubMed

    Zhu, Li; Yang, Zhong-Cheng; Li, Ao; Cheng, De-Chang

    2000-02-01

    AIM:To investigate the changes of gastric acid production and its mechanism in shock period of severe burn in rats.METHODS:A rat model with 30% TBSA full thickness burn injury was employed and the gastric acid production,together with gastric mucosal blood flow (GMBF) and energy charge (EC) were measured serially within 48h postburn.RESULTS:The gastric acid production in the acute shock period was markedly inhibited after severe burn injury.At the 3rd h postburn,the gastric juice volume, total acidity and acid output were already significantly decreased (P < 0.01 =, and reached the lowest point, 0.63mL/L ± 0.20mL/L, 10.81mmol/L ± 2.58mmol/L and 2.23mmol/h ± 0.73mmol/h respectively, at the 12th h postburn. Although restored to some degree 24h after thermal injury, the variables above were still statistically lower, compared with those of control animals at the 48th h postburn. The GMBF and EC were also significantly reduced after severe burns, consistent with the trend of gastric acid production changes.CONCLUSION:Gastric acid production, as well as GMBF and EC was predominantly decreased in the early postburn stage, suggesting that gastric mucosal ischemia and hypoxia with resultant disturbance in energy metabolism, but not gastric acid proper, might be the decisive factor in the pathogenesis of AGML after thermal injury, and that the preventive use of anti-acid drugs during burn shock period was unreasonable in some respects. Therefore, taking effective measures to improve gastric mucosal blood perfusion as early as possible postburn might be more preferable for the AGML prevention and treatment. PMID:11819529

  16. COX-2, aspirin and metabolism of arachidonic, eicosapentaenoic and docosahexaenoic acids and their physiological and clinical significance.

    PubMed

    Poorani, R; Bhatt, Anant N; Dwarakanath, B S; Das, Undurti N

    2016-08-15

    Polyunsaturated fatty acids (PUFAs) are vital for normal growth and development and physiological function of various tissues in humans. PUFAs have immunomodulatory actions in addition to their ability to modulate inflammation, vascular reactivity, neurotransmission and stem cell biology. PUFAs and their metabolites possess both pro- and anti-inflammatory properties that underlie their actions and involvement in several diseases. Aspirin, a non-steroidal anti-inflammatory drug (NSAID), possesses both cyclo-oxygenase (COX) and lipoxygenase (LOX) inhibitory action and enhances the production of anti-inflammatory lipoxin A4 {(called as epi-lipoxin A4, aspirin-triggered lipoxins (ATLs))}. In addition, at low doses aspirin may not interfere with the production of prostacyclin (PGI2). Both lipoxin A4 and PGI2 have vasodilator, platelet anti-aggregator and anti-inflammatory actions that may underlie the beneficial actions of aspirin. Paradoxically, other NSAIDs may not have the same actions as that of aspirin on PUFA metabolism. Similar anti-inflammatory compounds are formed from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by the action of aspirin termed as resolvins (from EPA and DHA) and protectins and maresins from DHA. PUFAs: arachidonic acid (AA), EPA and DHA and their various products modulate not only inflammation and immune response but also possess actions on various genes, nuclear factors, cyclic AMP and GMP, G-protein coupled receptors (GPRs), hypothalamic neurotransmitters, hormones, cytokines and enzymes, and interact with nitric oxide, carbon monoxide, and hydrogen sulfide to regulate their formation and action and to form new compounds that have several biological actions. These pleiotropic actions of PUFAs and their metabolites may explain their ability to play a role in several physiological actions and diseases. The big challenge is to harness these actions to prevent and manage clinical conditions. PMID:26335394

  17. Insights on the solubilization products after combined alkaline and ultrasonic pre-treatment of sewage sludge.

    PubMed

    Tian, Xinbo; Wang, Chong; Trzcinski, Antoine Prandota; Lin, Leonard; Ng, Wun Jern

    2015-03-01

    This work provides insights on the solubilization products after a simultaneous combination of alkaline and ultrasonic (ALK+ULS) pre-treatment of sewage sludge. Soluble chemical oxygen demand (SCOD) increased from 1200 to 11,000 mg/L after such treatment. Organics with molecular weight around 5.6 kDa were solubilized because of the synergistic effect of ultrasound and alkali. Organics with molecular weight larger than 300 kDa increased from 7.8% to 60%, 16% and 42.3% after ULS, ALK and ALK+ULS treatment, respectively. Excitation emission matrix fluorescence spectroscopy analysis identified soluble microbial product-like and humic acid-like matters as the main solubilization products. Sludge anaerobic biodegradability was significantly enhanced with the simultaneous application of ALK+ULS pre-treatment. ALK+ULS pre-treatment resulted in 37.8% biodegradability increase compared to the untreated sludge. This value was higher compared to the biodegradability increase induced by individual ALK pre-treatment (5.7%) or individual ULS pre-treatment (20.7%) under the same conditions applied. PMID:25766017

  18. Enzymatic pretreatment of low-grade oils for biodiesel production.

    PubMed

    Nordblad, Mathias; Pedersen, Anders K; Rancke-Madsen, Anders; Woodley, John M

    2016-04-01

    The alkaline process for making biodiesel (fatty acid methyl esters, or FAME) is highly efficient at the transesterification of glycerides. However, its performance is poor when it comes to using oil that contain significant amounts of free fatty acids (FFA). The traditional approach to such feedstocks is to employ acid catalysis, which is slow and requires a large excess of methanol, or to evaporate FFA and convert that in a separate process. An attractive option would be to convert the FFA in oil feedstocks to FAME, before introducing it into the alkaline process. The high selectivity of enzyme catalysis makes it a suitable basis for such a pretreatment process. In this work, we present a characterization of the pretreatment of high-FFA rapeseed oil using immobilized Candida antarctica lipase B (Novozym 435), focused on the impact of initial FFA and methanol concentration. Based on experimental results, we have identified limitations for the process in terms of FFA concentration in the feedstock and make suggestions for process operation. It was found that, using 5% catalyst and 4% methanol at 35°C, the FFA concentration could be reduced to 0.5% within an hour for feedstock containing up to 15% FFA. Further, the reaction was observed to be under kinetic control, in that the biocatalyst converts FFA (and FAME) at a much higher rate than glyceride substrates. There is thus, both a minimum and a maximum reaction time for the process to achieve the desired concentration of FFA. Finally, an assessment of process stability in a continuous packed bed system indicates that as much as 15 m(3) oil could potentially be pretreated by 1 kg of biocatalyst at the given process conditions. PMID:26442879

  19. Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

    SciTech Connect

    Stinson, Jake L. Ford, Ian J.; Kathmann, Shawn M.

    2014-01-14

    The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei, and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics method at the density functional level of theory. The general effect of zero-point motion is to distort the mean structure slightly, and to promote the extent of proton transfer with respect to classical behaviour. In a particular configuration of one sulphuric acid molecule with three waters, the range of positions explored by a proton between a sulphuric acid and a water molecule at 300 K (a broad range in contrast to the confinement suggested by geometry optimisation at 0 K) is clearly affected by the inclusion of zero point motion, and similar effects are observed for other configurations.

  20. Estimates of Soil Bacterial Ribosome Content and Diversity Are Significantly Affected by the Nucleic Acid Extraction Method Employed.

    PubMed

    Wüst, Pia K; Nacke, Heiko; Kaiser, Kristin; Marhan, Sven; Sikorski, Johannes; Kandeler, Ellen; Daniel, Rolf; Overmann, Jörg

    2016-05-01

    Modern sequencing technologies allow high-resolution analyses of total and potentially active soil microbial communities based on their DNA and RNA, respectively. In the present study, quantitative PCR and 454 pyrosequencing were used to evaluate the effects of different extraction methods on the abundance and diversity of 16S rRNA genes and transcripts recovered from three different types of soils (leptosol, stagnosol, and gleysol). The quality and yield of nucleic acids varied considerably with respect to both the applied extraction method and the analyzed type of soil. The bacterial ribosome content (calculated as the ratio of 16S rRNA transcripts to 16S rRNA genes) can serve as an indicator of the potential activity of bacterial cells and differed by 2 orders of magnitude between nucleic acid extracts obtained by the various extraction methods. Depending on the extraction method, the relative abundances of dominant soil taxa, in particularActinobacteriaandProteobacteria, varied by a factor of up to 10. Through this systematic approach, the present study allows guidelines to be deduced for the selection of the appropriate extraction protocol according to the specific soil properties, the nucleic acid of interest, and the target organisms. PMID:26896137

  1. Ensiling of wheat straw decreases the required temperature in hydrothermal pretreatment

    PubMed Central

    2013-01-01

    Background Ensiling is a well-known method for preserving green biomasses through anaerobic production of organic acids by lactic acid bacteria. In this study, wheat straw is subjected to ensiling in combination with hydrothermal treatment as a combined pretreatment method, taking advantage of the produced organic acids. Results Ensiling for 4 weeks was accomplished in a vacuum bag system after addition of an inoculum of Lactobacillus buchneri and 7% w/w xylose to wheat straw biomass at 35% final dry matter. Both glucan and xylan were preserved, and the DM loss after ensiling was less than 0.5%. When comparing hydrothermally treated wheat straw (170, 180 and 190°C) with hydrothermally treated ensiled wheat straw (same temperatures), several positive effects of ensiling were revealed. Glucan was up-concentrated in the solid fraction and the solubilisation of hemicellulose was significantly increased. Subsequent enzymatic hydrolysis of the solid fractions showed that ensiling significantly improved the effect of pretreatment, especially at the lower temperatures of 170 and 180°C. The overall glucose yields after pretreatments of ensiled wheat straw were higher than for non-ensiled wheat straw hydrothermally treated at 190°C, namely 74-81% of the theoretical maximum glucose in the raw material, which was ~1.8 times better than the corresponding yields for the non-ensiled straw pretreated at 170 or 180°C. The highest overall conversion of combined glucose and xylose was achieved for ensiled wheat straw hydrothermally treated at 180°C, with overall glucose yield of 78% and overall conversion yield of xylose of 87%. Conclusions Ensiling of wheat straw is shown to be an effective pre-step to hydrothermal treatment, and can give rise to a welcomed decrease of process temperature in hydrothermal treatments, thereby potentially having a positive effect on large scale pretreatment costs. PMID:23945109

  2. Pretreatment of CO oxidation catalysts

    NASA Technical Reports Server (NTRS)

    Vannorman, John D.

    1988-01-01

    CO oxidation catalysts with high activity in the range of 25 C to 100 C are important for long-life, closed-cycle operation of pulsed carbon dioxide 2 lasers. A reductive pretreatment with either CO or H sub 2 was shown to significantly enhance the activity of a commerically-available platinum on tin (IV) oxide (Pt/SnO2) catalyst relative to an oxidative or inert pretreatment or no pretreatment. Pretreatment at temperatures of 175 C and above caused an initial dip in observed CO or O sub 2 loss or CO sub 2 formation in a test gas mixture of 1 percent CO and 0.5 percent O sub 2 in a He gas matrix before a steady-state yield was obtained. This dip was found to be caused by dehydration of the surface of the catalyst and was readily eliminated by humidifying the catalyst or the test gas mixture. It was also found that too much moisture resulted in a lower overall yield of CO sub 2. Under similar conditions, it is hypothesized that the effect of the humidification is to increase the concentration of OH groups on the surface of the catalyst. The effect of having high concentration of CO sub 2 in the test gas mixture upon the loss of CO and O sub 2 as well as the effect of periods of relaxation of the catalyst under non-test gas conditions was studied. The purpose of these studies was to gain an insight into the mechanism of CO oxidation on this type of catalyst.

  3. Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

    PubMed Central

    2011-01-01

    Background While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb) was used as a model feedstock. Results Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein) respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Conclusions Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for significant ethanol cost

  4. Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass.

    PubMed

    Fernandes, T V; Bos, G J Klaasse; Zeeman, G; Sanders, J P M; van Lier, J B

    2009-05-01

    The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After pre-treatment, the plant material was anaerobically digested in batch bottles under mesophilic conditions for 40 days. From the pre-treatment and subsequent anaerobic digestion experiments, it was concluded that when the lignin content of the plant material is high, thermo-chemical pre-treatments have a positive effect on the biodegradability of the substrate. Calcium hydroxide pre-treatment improves the biodegradability of lignocellulosic biomass, especially for high lignin content substrates, like bracken. Maleic acid generates the highest percentage of dissolved COD during pre-treatment. Ammonium pre-treatment only showed a clear effect on biodegradability for straw. PMID:19144515

  5. On the Nutritive Significance of Dissolved Free Amino Acid Uptake for the Cosmopolitan Oligochaete Nais elinguisMüller (Naididae)

    NASA Astrophysics Data System (ADS)

    Petersen, S.; Arlt, G.; Faubel, A.; Carman, K. R.

    1998-01-01

    Uptake of dissolved free amino acids (DFAA) byNais elinguisMüller from a brackish water lagoon has been confirmed by autoradiographic studies, liquid scintillation counting of animals incubated with labelled DFAA, and by HPLC analysis of the incubation water. Net uptake was shown to occur at ambient DFAA concentrations. The results indicate that most of the absorbed DFAA were respired, and only a minor portion was incorporated into proteins. Parallel determination of respiration and DFAA uptake in a flow-through system allowed a calculation of the contribution of uptake to the maintainance metabolism ofN. elinguis. The average weight-specific uptake rate of mixed DFAA was 1·4 μmol g-1h-1at a salinity of 6 and 4·1 μmol g-1h-1at a salinity of 12 (temperature 20 °C). Assuming that 10 μmol of mixed amino acids (average mol wt. 100) require 44·64 μmol O2for complete oxidation, the nutritional profit of DFAA absorption at a salinity of 6 accounted for 7% of the total oxidative needs and for 24% at a salinity of 12. The results demonstrate that DFAA uptake can provide an important nutritional input.

  6. Solution structure of gamma-bungarotoxin: the functional significance of amino acid residues flanking the RGD motif in integrin binding.

    PubMed

    Shiu, Jia-Hau; Chen, Chiu-Yueh; Chang, Long-Sen; Chen, Yi-Chun; Chen, Yen-Chin; Lo, Yu-Hui; Liu, Yu-Chen; Chuang, Woei-Jer

    2004-12-01

    Gamma-bungarotoxin, a snake venom protein isolated from Bungarus multicinctus, contains 68 amino acids, including 10 cysteine residues and a TAVRGDGP sequence at positions 30-37. The solution structure of gamma-bungarotoxin has been determined by nuclear magnetic resonance (NMR) spectroscopy. The structure is similar to that of the short-chain neurotoxins that contain three loops extending from a disulfide-bridged core. The tripeptide Arg-Gly-Asp (RGD) sequence is located at the apex of the flexible loop and is similar to that of other RGD-containing proteins. However, gamma-bungarotoxin only inhibits platelet aggregations with an IC50 of 34 microM. To understand its weak activity in inhibiting platelet aggregation, we mutated the RGD loop sequences of rhodostomin, a potent platelet aggregation inhibitor, from RIPRGDMP to TAVRGDGP, resulting in a 196-fold decrease in activity. In addition, the average Calpha-to-Calpha distance between R33 and G36 of gamma-bungarotoxin is 6.02 A, i.e., shorter than that of other RGD-containing proteins that range from 6.55 to 7.46 A. These results suggested that the amino acid residues flanking the RGD motif might control the width of the RGD loop. This structural difference may be responsible for its decrease in platelet aggregation inhibition compared with other RGD-containing proteins. PMID:15390258

  7. Surface functionalization of bioactive glasses with natural molecules of biological significance, Part I: Gallic acid as model molecule

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Gallic acid (3,4,5-trihydroxybenzoic acid, GA) and its derivatives are a group of biomolecules (polyphenols) obtained from plants. They have effects which are potentially beneficial to heath, for example they are antioxidant, anticarcinogenic and antibacterial, as recently investigated in many fields such as medicine, food and plant sciences. The main drawbacks of these molecules are both low stability and bioavailability. In this research work the opportunity to graft GA to bioactive glasses is investigated, in order to deliver the undamaged biological molecule into the body, using the biomaterial surfaces as a localized carrier. GA was considered for functionalization since it is a good model molecule for polyphenols and presents several interesting biological activities, like antibacterial, antioxidant and anticarcinogenic properties. Two different silica based bioactive glasses (SCNA and CEL2), with different reactivity, were employed as substrates. UV photometry combined with the Folin&Ciocalteu reagent was adopted to test the concentration of GA in uptake solution after functionalization. This test verified how much GA consumption occurred with surface modification and it was also used on solid samples to test the presence of GA on functionalized glasses. XPS and SEM-EDS techniques were employed to characterize the modification of material surface properties and functional group composition before and after functionalization.

  8. Superfund explanation of significant difference for the record of decision (EPA Region 9): Stringfellow Acid Pits, Riverside, CA, July 9, 1998

    SciTech Connect

    Not Available

    1999-03-01

    This document presents the explanation of significant differences (ESD) for a proposed change to the remedy chosen to the second Record of Decision (ROD2) for the Stringfellow Superfund site (the Site''). Currently, contaminated groundwater is being extracted from a series of wells located in the original disposal area of the Site and in downgradient, contaminated zones just to the south. The extracted groundwater is pumped to the on-site Stringfellow pretreatment plant (the PTP'') where the water is treated to remove site contaminants. The treated water from the PTP is then transported by tanker truck and discharged into the regional wastewater collection system, commonly known as the Santa Ana Regional Interceptor (SARI), that serves the upper Santa Ana River watershed area. Since the time ROD2 was completed, the SARI has been extended and now passes within 1.5 miles of the Stringfellow PTP. A direct pipeline to the SARI line would eliminate the tanker truck trips on the regional highways and municipal streets, and result in a significant reduction in operating costs of the Stringfellow PTP.

  9. Hydrogelation Induced by Change in Hydrophobicity of Amino Acid Side Chain in Fmoc-Functionalised Amino Acid: Significance of Sulfur on Hydrogelation.

    PubMed

    Reddy, Samala Murali Mohan; Dorishetty, Pramod; Deshpande, Abhijit P; Shanmugam, Ganesh

    2016-07-18

    Although a few Fmoc-functionalised amino acids (Fmoc-AA) are capable of forming hydrogels, the exact levels of hydrophobicity, hydrogen bonding, and ionic nature of the Fmoc-AA gelator required for hydrogel formation remains uncertain. Here, the role of hydrophobicity of amino acid side chain, particularly in the formation of hydrogel, was studied by using Fmoc-norleucine (Fmoc-Nle) and its simple sulfur analogues such as Fmoc-methionine (Fmoc-M) in which the γCH2 of Fmoc-Nle is replaced by sulfur. Results indicate that Fmoc-M forms thermally reversible hydrogels in water (pH ca. 6.8), whereas Fmoc-Nle fails to display any gelation under similar conditions. The result suggests that substitution of the sulfur atom likely reduces the hydrophobicity of the alkyl side chain in Fmoc-Nle to the optimum level, which is sufficient to induce supramolecular hydrogelation in Fmoc-M. The difference in the self-association behaviour of Fmoc-M and Fmoc-Nle emphasise the importance of weak noncovalent interaction between side chains (in addition to the hydrogen-bond and aromatic interactions) to stabilise supramolecular self-assembly of Fmoc-functionalised compounds. The current observations provide a lead to the design of new sulfur-based low molecular weight gelators for various potential applications. PMID:27017582

  10. Resveratrol Pretreatment Ameliorates TNBS Colitis in Rats

    PubMed Central

    Yildiz, Gulserap; Yildiz, Yuksel; Ulutas, Pinar A.; Yaylali, Aslı; Ural, Muruvvet

    2015-01-01

    Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory disease in humans constituting a major health concern today whose prevalence has been increasing over the world. Production of reactive oxygen species (ROS) and disturbed capacity of antioxidant defense in IBD subjects have been reported. Antioxidants may play a significant role in IBD treatment. This study aimed at evaluating ameliorative effects of intraperitoneal resveratrol pretreatment on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. Thirty five Wistar-Albino female rats were divided equally into five groups. Inflammation was induced by the intrarectal administration of TNBS under anesthesia. Intraperitoneal administration of resveratrol (RSV) at a concentration of 10mg/kg/day for 5 days before the induction of colitis significantly reduced microscopy score and malondialdehyde (MDA) levels and increased glutathione peroxidase (GSH Px) activity compared to TNBS and vehicle groups. Also an insignificant increase in catalase (CAT) activity was observed in the RSV treated group compared to TNBS and vehicle groups. In this paper, the most recent patent on the identification and treatment of IBD was indicated. In conclusion, antioxidant RSV proved to have a beneficial effect on TNBS colitis in rats. In light of these advantageous results, the RSV can be considered as adjuvant agent in IBD treatments. PMID:26246013

  11. Resveratrol Pretreatment Ameliorates TNBS Colitis in Rats.

    PubMed

    Yildiz, Gulserap; Yildiz, Yuksel; Ulutas, Pinar A; Yaylali, Asl; Ural, Muruvvet

    2015-01-01

    Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory disease in humans constituting a major health concern today whose prevalence has been increasing over the world. Production of reactive oxygen species (ROS) and disturbed capacity of antioxidant defense in IBD subjects have been reported. Antioxidants may play a significant role in IBD treatment. This study aimed at evaluating ameliorative effects of intraperitoneal resveratrol pretreatment on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. Thirty five Wistar-Albino female rats were divided equally into five groups. Inflammation was induced by the intrarectal administration of TNBS under anesthesia. Intraperitoneal administration of resveratrol (RSV) at a concentration of 10mg/kg/day for 5 days before the induction of colitis significantly reduced microscopy score and malondialdehyde (MDA) levels and increased glutathione peroxidase (GSH Px) activity compared to TNBS and vehicle groups. Also an insignificant increase in catalase (CAT) activity was observed in the RSV treated group compared to TNBS and vehicle groups. In this paper, the most recent patent on the identification and treatment of IBD was indicated. In conclusion, antioxidant RSV proved to have a beneficial effect on TNBS colitis in rats. In light of these advantageous results, the RSV can be considered as adjuvant agent in IBD treatments. PMID:26246013

  12. p-Sulfonic Acid Calix[4]arene as an Efficient Catalyst for One-Pot Synthesis of Pharmaceutically Significant Coumarin Derivatives under Solvent-Free Condition

    PubMed Central

    Tashakkorian, Hamed; Lakouraj, Moslem Mansour; Rouhi, Mona

    2015-01-01

    One-pot and efficient protocol for preparation of some potent pharmaceutically valuable coumarin derivatives under solvent-free condition via direct coupling using biologically nontoxic organocatalyst, calix[4]arene tetrasulfonic acid (CSA), was introduced. Calix[4]arene sulfonic acid has been incorporated lately as a magnificent and recyclable organocatalyst for the synthesis of some organic compounds. Nontoxicity, solvent-free conditions, good-to-excellent yields for pharmaceutically significant structures, and especially ease of catalyst recovery make this procedure valuable and environmentally benign. PMID:26798517

  13. Effect of EDTA Conditioning and Carbodiimide Pretreatment on the Bonding Performance of All-in-One Self-Etch Adhesives

    PubMed Central

    Singh, Shipra; Nagpal, Rajni; Tyagi, Shashi Prabha; Manuja, Naveen

    2015-01-01

    Objective. This study evaluated the effect of ethylenediaminetetraacetic acid (EDTA) conditioning and carbodiimide (EDC) pretreatment on the shear bond strength of two all-in-one self-etch adhesives to dentin. Methods. Flat coronal dentin surfaces were prepared on one hundred and sixty extracted human molars. Teeth were randomly divided into eight groups according to two different self-etch adhesives used [G-Bond and OptiBond-All-In-One] and four different surface pretreatments: (a) adhesive applied following manufacturer's instructions; (b) dentin conditioning with 24% EDTA gel prior to application of adhesive; (c) EDC pretreatment followed by application of adhesive; (d) application of EDC on EDTA conditioned dentin surface followed by application of adhesive. Composite restorations were placed in all the samples. Ten samples from each group were subjected to immediate and delayed (6-month storage in artificial saliva) shear bond strength evaluation. Data collected was subjected to statistical analysis using three-way ANOVA and post hoc Tukey's test at a significance level of p < 0.05.  Results and Conclusion. EDTA preconditioning as well as EDC pretreatment alone had no significant effect on the immediate and delayed bond strengths of either of the adhesives. However, EDC pretreatment on EDTA conditioned dentin surface resulted in preservation of resin-dentin bond strength of both adhesives with no significant fall over six months. PMID:26557850

  14. A Naturally Occurring Single Amino Acid Replacement in Multiple Gene Regulator of Group A Streptococcus Significantly Increases Virulence

    PubMed Central

    Sanson, Misu; O'Neill, Brian E.; Kachroo, Priyanka; Anderson, Jeff R.; Flores, Anthony R.; Valson, Chandni; Cantu, Concepcion C.; Makthal, Nishanth; Karmonik, Christof; Fittipaldi, Nahuel; Kumaraswami, Muthiah; Musser, James M.; Olsen, Randall J.

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) are the most common source of genetic variation within a species; however, few investigations demonstrate how naturally occurring SNPs may increase strain virulence. We recently used group A Streptococcus as a model pathogen to study bacteria strain genotype–patient disease phenotype relationships. Whole-genome sequencing of approximately 800 serotype M59 group A Streptococcus strains, recovered during an outbreak of severe invasive infections across North America, identified a disproportionate number of SNPs in the gene encoding multiple gene regulator of group A Streptococcus (mga). Herein, we report results of studies designed to test the hypothesis that the most commonly occurring SNP, encoding a replacement of arginine for histidine at codon 201 of Mga (H201R), significantly increases virulence. Whole transcriptome analysis revealed that the H201R replacement significantly increased expression of mga and 54 other genes, including many proven virulence factors. Compared to the wild-type strain, a H201R isogenic mutant strain caused significantly larger skin lesions in mice. Serial quantitative bacterial culture and noninvasive magnetic resonance imaging also demonstrated that the isogenic H201R strain was significantly more virulent in a nonhuman primate model of joint infection. These findings show that the H201R replacement in Mga increases the virulence of M59 group A Streptococcus and provide new insight to how a naturally occurring SNP in bacteria contributes to human disease phenotypes. PMID:25476528

  15. A naturally occurring single amino acid replacement in multiple gene regulator of group A Streptococcus significantly increases virulence.

    PubMed

    Sanson, Misu; O'Neill, Brian E; Kachroo, Priyanka; Anderson, Jeff R; Flores, Anthony R; Valson, Chandni; Cantu, Concepcion C; Makthal, Nishanth; Karmonik, Christof; Fittipaldi, Nahuel; Kumaraswami, Muthiah; Musser, James M; Olsen, Randall J

    2015-02-01

    Single-nucleotide polymorphisms (SNPs) are the most common source of genetic variation within a species; however, few investigations demonstrate how naturally occurring SNPs may increase strain virulence. We recently used group A Streptococcus as a model pathogen to study bacteria strain genotype-patient disease phenotype relationships. Whole-genome sequencing of approximately 800 serotype M59 group A Streptococcus strains, recovered during an outbreak of severe invasive infections across North America, identified a disproportionate number of SNPs in the gene encoding multiple gene regulator of group A Streptococcus (mga). Herein, we report results of studies designed to test the hypothesis that the most commonly occurring SNP, encoding a replacement of arginine for histidine at codon 201 of Mga (H201R), significantly increases virulence. Whole transcriptome analysis revealed that the H201R replacement significantly increased expression of mga and 54 other genes, including many proven virulence factors. Compared to the wild-type strain, a H201R isogenic mutant strain caused significantly larger skin lesions in mice. Serial quantitative bacterial culture and noninvasive magnetic resonance imaging also demonstrated that the isogenic H201R strain was significantly more virulent in a nonhuman primate model of joint infection. These findings show that the H201R replacement in Mga increases the virulence of M59 group A Streptococcus and provide new insight to how a naturally occurring SNP in bacteria contributes to human disease phenotypes. PMID:25476528

  16. Merging the Structural Motifs of Functionalized Amino Acids and α-Aminoamides: Compounds with Significant Anticonvulsant Activities

    PubMed Central

    Salomé, Christophe; Salomé-Grosjean, Elise; Stables, James P.; Kohn, Harold

    2010-01-01

    Functional amino acids (FAAs) and α-aminoamides (AAAs) are two classes of antiepileptic drugs (AEDs) that exhibit pronounced anticonvulsant activities. We combined key structural pharmacophores present in FAAs and AAAs to generate a new series of compounds and document that select compounds exhibit activity superior to either the prototypical FAA (lacosamide) or the prototypical AAA (safinamide) in the maximal electroshock (MES) seizure model in rats. A representative compound, (R)-N-4′-((3″-fluoro)benzyloxy)benzyl 2-acetamido-3-methoxypropionamide ((R)-10), was tested in the MES (mice, ip), MES (rat, po), psychomotor 6 Hz (32 mA) (mice, ip), and hippocampal kindled (rat, ip) seizure tests providing excellent protection with ED50 values of 13, 14, ~10 mg/kg, and 12 mg/kg, respectively. In the rat sciatic nerve ligation model (ip), (R)-10 (12 mg/kg) provided an 11.2-fold attenuation of mechanical allodynia. In the mouse biphasic formalin pain model (ip), (R)-10 (15 mg/kg) reduced pain responses in the acute and the chronic inflammatory phases. PMID:20394379

  17. The Significance of Lewis Acid Sites for the Selective Catalytic Reduction of Nitric Oxide on Vanadium-Based Catalysts.

    PubMed

    Marberger, Adrian; Ferri, Davide; Elsener, Martin; Kröcher, Oliver

    2016-09-19

    The long debated reaction mechanisms of the selective catalytic reduction (SCR) of nitric oxide with ammonia (NH3 ) on vanadium-based catalysts rely on the involvement of Brønsted or Lewis acid sites. This issue has been clearly elucidated using a combination of transient perturbations of the catalyst environment with operando time-resolved spectroscopy to obtain unique molecular level insights. Nitric oxide reacts predominantly with NH3 coordinated to Lewis sites on vanadia on tungsta-titania (V2 O5 -WO3 -TiO2 ), while Brønsted sites are not involved in the catalytic cycle. The Lewis site is a mono-oxo vanadyl group that reduces only in the presence of both nitric oxide and NH3 . We were also able to verify the formation of the nitrosamide (NH2 NO) intermediate, which forms in tandem with vanadium reduction, and thus the entire mechanism of SCR. Our experimental approach, demonstrated in the specific case of SCR, promises to progress the understanding of chemical reactions of technological relevance. PMID:27553251

  18. Lipid droplets in activated mast cells - a significant source of triglyceride-derived arachidonic acid for eicosanoid production.

    PubMed

    Dichlberger, Andrea; Schlager, Stefanie; Kovanen, Petri T; Schneider, Wolfgang J

    2016-08-15

    Mast cells are potent effectors of immune reactions and key players in various inflammatory diseases such as atherosclerosis, asthma, and rheumatoid arthritis. The cellular defense response of mast cells represents a unique and powerful system, where external signals can trigger cell activation resulting in a stimulus-specific and highly coordinated release of a plethora of bioactive mediators. The arsenal of mediators encompasses preformed molecules stored in cytoplasmic secretory granules, as well as newly synthesized proteinaceous and lipid mediators. The release of mediators occurs in strict chronological order and requires proper coordination between the endomembrane system and various enzymatic machineries. For the generation of lipid mediators, cytoplasmic lipid droplets have been shown to function as a major intracellular pool of arachidonic acid, the precursor for eicosanoid biosynthesis. Recent studies have revealed that not only phospholipids in mast cell membranes, but also triglycerides in mast cell lipid droplets are a substrate source for eicosanoid formation. The present review summarizes current knowledge about mast cell lipid droplet biology, and discusses expansions and challenges of traditional mechanistic models for eicosanoid production. PMID:26164793

  19. Quality Characteristics and Quantification of Acetaldehyde and Methanol in Apple Wine Fermentation by Various Pre-Treatments of Mash.

    PubMed

    Won, Seon Yi; Seo, Jae Soon; Kwak, Han Sub; Lee, Youngseung; Kim, Misook; Shim, Hyoung-Seok; Jeong, Yoonhwa

    2015-12-01

    The objective of this study was to compare the effects of adding lactic acid and pectinase, and chaptalization for the quality of apple wine and the production of hazardous compounds (methanol and acetaldehyde). The pH of all of the samples was below 4; therefore, mash seemed to be fermented without any issue. Total acidity was the highest in sample A due to lactic acid addition. Pre-treated groups (samples B, C, and D) showed higher total acidities than that of the control (P<0.05). Pre-treatments might influence the production of organic acids in apple wines. The control and pectinase added sample (sample B) had the lowest alcohol contents. Adding lactic acid produced more alcohol, and chaptalized samples produced more alcohol due to the addition of sugar. Adding pectinase with and without chaptalization was not effective for producing more alcohol. The control sample had significantly higher acetaldehyde content (2.39 mg/L) than the other samples (1.00~2.07 mg/L); therefore, pre-treatments for apple wine fermentation produced a lower amount of acetaldehyde. Among the pre-treated samples, samples C and D showed the lowest acetaldehyde content of 1.00 mg/L and 1.16 mg/L, respectively. On the other hand, a significantly higher amount of methanol was generated for sample A (1.03 mg/L) and sample D (1.22 mg/L) than that of the control (0.82 mg/L) (P<0.05). Adding lactic acid or chaptalization was effective in reducing methanol and acetaldehyde in apple wines. PMID:26770917

  20. Quality Characteristics and Quantification of Acetaldehyde and Methanol in Apple Wine Fermentation by Various Pre-Treatments of Mash

    PubMed Central

    Won, Seon Yi; Seo, Jae Soon; Kwak, Han Sub; Lee, Youngseung; Kim, Misook; Shim, Hyoung-Seok; Jeong, Yoonhwa

    2015-01-01

    The objective of this study was to compare the effects of adding lactic acid and pectinase, and chaptalization for the quality of apple wine and the production of hazardous compounds (methanol and acetaldehyde). The pH of all of the samples was below 4; therefore, mash seemed to be fermented without any issue. Total acidity was the highest in sample A due to lactic acid addition. Pre-treated groups (samples B, C, and D) showed higher total acidities than that of the control (P<0.05). Pre-treatments might influence the production of organic acids in apple wines. The control and pectinase added sample (sample B) had the lowest alcohol contents. Adding lactic acid produced more alcohol, and chaptalized samples produced more alcohol due to the addition of sugar. Adding pectinase with and without chaptalization was not effective for producing more alcohol. The control sample had significantly higher acetaldehyde content (2.39 mg/L) than the other samples (1.00~2.07 mg/L); therefore, pre-treatments for apple wine fermentation produced a lower amount of acetaldehyde. Among the pre-treated samples, samples C and D showed the lowest acetaldehyde content of 1.00 mg/L and 1.16 mg/L, respectively. On the other hand, a significantly higher amount of methanol was generated for sample A (1.03 mg/L) and sample D (1.22 mg/L) than that of the control (0.82 mg/L) (P<0.05). Adding lactic acid or chaptalization was effective in reducing methanol and acetaldehyde in apple wines. PMID:26770917

  1. Enzymatic conversion of pretreated biomass into fermentable sugars for biorefinery operation

    NASA Astrophysics Data System (ADS)

    Gao, Dahai

    2011-12-01

    formed during pretreatment impede accurate quantification of individual glycosyl hydrolases (GH) binding to pretreated cell walls. A high-throughput Fast Protein Liquid Chromatography (HT-FPLC) based method has been developed to quantify CBH I, CBH II and EG I present in hydrolyzates of untreated, AFEX, and dilute-acid pretreated corn stover. This method can accurately quantify individual enzymes present in complex binary and ternary protein mixtures without interference from plant cell wall derived components. The binding characteristics of CBH I, CBH II and EG I during 48 hours hydrolysis were studied on different cellulose allomorphs: microcrystalline cellulose Avicel (cellulose Ibeta), liquid ammonia treated cellulose (cellulose III), sodium hydroxide treated cellulose (cellulose II) and phosphoric acid swollen amorphous cellulose (AC). The digestibility ranking is AC>cellulose III>cellulose II>cellulose I. However, AC has the highest initial enzyme binding capacity while cellulose III had the lowest. CBH II is less stable during hydrolysis. Time course binding studies were also performed for pretreated biomass. Ammonia Fiber Expansion (AFEX) treated corn stover (CS), dilute acid (ACID) treated CS and ionic liquid (IL) pretreated CS were compared. The results indicate that presence of lignin is responsible for significant unproductive cellulase binding. These results are critical for improving our understanding of enzyme synergism, productive/unproductive enzyme binding and the role of pretreatment on enzyme accessibility to lignocellulosic plant cell walls. The results also assist in engineering novel low unproductive binding enzyme systems and developing economic enzyme recycle options.

  2. Ozonolysis: An advantageous pretreatment for lignocellulosic biomass revisited.

    PubMed

    Travaini, Rodolfo; Martín-Juárez, Judit; Lorenzo-Hernando, Ana; Bolado-Rodríguez, Silvia

    2016-01-01

    Ozonolysis, as a lignocellulosic biomass pretreatment, goes back to 80s; however, in the last years it is becoming widespread again owing to its efficiency and mild operation conditions. Ozone reacts preferably with lignin than carbohydrates, promoting biomass destructuration and delignification, and so the sugar release by enzymatic hydrolysis. The hydrolysate from pretreated biomass has being used as sugars source for second-generation fuels production, mainly ethanol, methane and hydrogen. Short-chain carboxylic acids are the main inhibitory compounds generated, being properly removed by water washing. The most common inhibitory compounds reported for other pretreatments, furfural and HMF (5-hydroxymethylfurfural), are not found in ozone-pretreated hydrolysates. Composition of pretreated biomass and ozone consumption depends on several process parameters: reactor design, moisture content, particle size, pH, reaction time, ozone/air flow and ozone concentration. Additional studies are necessary to clarify process parameters effect and to optimize the process to achieve high yields with economic feasibility. PMID:26409859

  3. CO.sub.2 Pretreatment prevents calcium carbonate formation

    DOEpatents

    Neavel, Richard C.; Brunson, Roy J.; Chaback, Joseph J.

    1980-01-01

    Scale formation during the liquefaction of lower ranking coals and similar carbonaceous materials is significantly reduced and/or prevented by pretreatment with carbon dioxide. The carbon dioxide pretreatment is believed to convert the scale-forming components to the corresponding carbonate prior to liquefaction. The pretreatment is accomplished at a total pressure within the range from about 14 to about 68 atmospheres and a carbon dioxide partial pressure within the range from about 14 to about 34 atmospheres. Temperature during pretreatment will generally be within the range from about 100.degree. to about 200.degree. C.

  4. Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

    SciTech Connect

    Stinson, Jake L.; Kathmann, Shawn M.; Ford, Ian J.

    2014-01-14

    The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei (CCN), and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics (PIMD) method at the density functional theory (DFT) level of theory. We observe a small zero-point effect on the the equilibrium structures of certain clusters. One configuration is found to display a bimodal behaviour at 300 K in contrast to the stable ionised state suggested from a zero temperature classical geometry optimisation. The general effect of zero-point motion is to promote the extent of proton transfer with respect to classical behaviour. We thank Prof. Angelos Michaelides and his group in University College London (UCL) for practical advice and helpful discussions. This work benefited from interactions with the Thomas Young Centre through seminar and discussions involving the PIMD method. SMK was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. JLS and IJF were supported by the IMPACT scheme at UCL and by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. We are grateful for use of the UCL Legion High Performance Computing Facility and the

  5. Remarkable activity of PdIr nanoparticles supported on the surface of carbon nanotubes pretreated via a sonochemical process for formic acid electro-oxidation

    NASA Astrophysics Data System (ADS)

    Chen, Jinwei; Li, Yuanjie; Liu, Shuangren; Wang, Gang; Tian, Jing; Jiang, Chunping; Zhu, Shifu; Wang, Ruilin

    2013-12-01

    It was reported for the first time that the surface treated multi-walled carbon nanotubes supported PdIr (PdIr/CNT-SCP) catalyst presents remarkable electrocatalytic activity and stability for formic acid electro-oxidation (FAEO). The surface of CNTs was functionalized by a sonochemical process for the deposition of PdIr nanoparticles (NPs). The XRD and TEM characterizations show that the prepared PdIr/CNT-SCP catalyst has small mean size and good dispersion of PdIr NPs on CNTs. The electrochemical measurements show that the onset and anodic peak potentials of FAEO on PdIr/CNT-SCP catalyst are 60 and 50 mV more negative than that on the commercial Pd/C catalyst. The mass-normalized peak current density of PdIr/CNT-SCP is 3365 mA mg-1Pd, which is 4.5, 1.4 and 2.7 times higher than that of PdIr/CNT-Untreated, PdIr/C-SCP and commercial Pd/C, respectively. It demonstrates the promotion of Ir and functionalized CNTs to Pd for FAEO.

  6. Indomethacin pretreatment reduces ozone-induced pulmonary function decrements in human subjects

    SciTech Connect

    Schelegle, E.S.; Adams, W.C.; Siefkin, A.D.

    1987-12-01

    We studied whether O/sub 3/-induced pulmonary function decrements could be inhibited by the prostaglandin synthetase inhibitor, indomethacin, in healthy human subjects. Fourteen college-age males completed six 1-h exposure protocols consisting of no drug, placebo, and indomethacin (Indocin SR 75 mg every 12 h for 5 days) pretreatments, with filtered air and O/sub 3/ (0.35 ppm) exposures within each pretreatment. Pretreatments were delivered weekly in random order in a double-blind fashion. Ozone and filtered air exposures, separated by 72 h, were delivered in random order in a single-blind fashion. Exposures consisted of 1-h exercise on a bicycle ergometer with work loads set to elicit a mean minute ventilation of 60 L/min. Statistical analysis revealed significant (p less than 0.05) across pretreatment effects for FVC and FEV1, with no drug versus indomethacin and placebo versus indomethacin comparisons being significant. These findings suggest that cyclooxygenase products of arachidonic acid, which are sensitive to indomethacin inhibition, play a prominent role in the development of pulmonary function decrements consequent to acute O/sub 3/ exposure.

  7. Client Perceptions of Pretreatment Change

    ERIC Educational Resources Information Center

    Kindsvatter, Aaron; Osborn, Cynthia J.; Bubenzer, Donald; Duba, Jill D.

    2010-01-01

    The authors suggest that when counselors have a rich understanding of pretreatment changes, they are better able to assist clients in capitalizing on such changes. The current study examined client perceptions of pretreatment changes. Thirty-six clients completed Q-sorts pertaining to pretreatment changes they experienced. Four factors pertaining…

  8. Evaluation of the improvement of sonication pre-treatment in the anaerobic digestion of sewage sludge.

    PubMed

    Martín, María Ángeles; González, Inmaculada; Serrano, Antonio; Siles, José Ángel

    2015-01-01

    Sewage sludge is a polluting and hazardous waste generated in wastewater treatment plants with severe management problems. The high content in heavy metal, pathogens and micropolluting compounds limit the implementation of the available management methods. Anaerobic digestion could be an interesting treatment method, but must be improved since the biomethanisation of sewage sludge entails low biodegradability and low methane production. A sonication pre-treatment at lab scale is proposed to increase the organic matter solubilisation of sewage sludge and enhance the biomethanisation yield. Sonication time was optimised by analysing the physicochemical characteristics of sewage sludge (both total and soluble fraction) at different pre-treatment times. The pre-treatment time was fixed at 45 min under the study conditions given that the solubilisation of organic matter did not increase significantly at lower sonication times, whereas the concentration of total nitrogen increased markedly at higher times. The volatile fatty acids generation rate was also evaluated for the pre-treatment conditions. The anaerobic digestion of untreated and pre-treated sewage sludge was subsequently compared and promising results were obtained for loads of 1.0 g VS/L (VS, total volatile solids). The methane yield coefficient increased from 88 to 172 mLSTP/g VS (STP, 0 °C, 1 atm) after the pre-treatment, while biodegradability was found to be around 81% (in VS). Moreover, the allowed organic loading rate and methane production rate observed for the sewage sludge reached values of up to 4.1 kg VS/m(3)·d and 1270 LSTP/m(3)·d, respectively. PMID:25284801

  9. Significant enhancement of photoreactivity of graphitic carbon nitride catalysts under acidic conditions and the underlying H(+)-mediated mechanism.

    PubMed

    Zhang, Xue-Song; Tian, Ke; Hu, Jian-Yang; Jiang, Hong

    2015-12-01

    Graphitic carbon nitride (g-C3N4) is an emerging photocatalyst for organic pollutants degradation owing to its excellent stability and metal-free property. In this study, the photocatalytic activity of acidified g-C3N4 (ag-C3N4) was systematically investigated using rhodamine B (rhB) as a model organic pollutant. The results showed the photoreactivity of ag-C3N4 is significantly enhanced with the decrease of pH values. The apparent rate constant (kapp) of rhB degradation over ag-C3N4 is 11.59×10(-3)min(-1) at pH7.0 and it increases to 103.50×10(-3)min(-1) at pH3.0 under visible light. A series of analyses demonstrate that the photodegradation mechanism is a combination of a H(+)-promoted generation of OH and elevation of the redox potential of conduct band of C3N4. The change of surface properties of C3N4 caused by pH variation also affects the degradation of some zwitterionic compounds by changing the adsorption orientation of pollutants. The revealed mechanism of visible light-C3N4-rhB system is meaningful to broaden the usage of C3N4 to the photodegradation of other organic pollutants. PMID:26172516

  10. [The noninvasive evaluation of degree of expression of fibrosis of liver and significance of polymorphism of gene of hyaluronic acid under chronic hepatitis C].

    PubMed

    Bulatova, I A; Schekotova, A P; Krivtsov, A V; Schekotov, V V; Pavlov, A I

    2015-03-01

    The study was carries out to evaluate degree of expression of fibrosis, reparation processes in liver and value of polymorphism of gene of hyaluronic acid HASI (rs11084111) in progression of affection of liver in patients with chronic hepatitis C. The sampling included 100 patients with chronic hepatitis C. The control group included 83 healthy donors. The blood serum was tested to detect concentration of hyaluronic acid and alpha-fetoprotein. The stage of liver fibrosis (F) was evaluated by using ultrasound fibroflexography The polymorphism of gene (rs11084111) was analysed by polymerase chain reaction technique. In the group of patients with F1 the average concentration of hyaluronic acid in blood serum in 1.8 times surpassed this indicator in group with F0. The concentration of hyaluronic acid was almost 2 times higher under F3 as compared with F1-F2. This indicator permitted differentiating F3 and F4 which followed by activation of cytolysis and cholestasis in F1 and F3 and by increasing of level of alpha-fetoprotein at stages F1 and F4. The study detected no statistically significant difference between rates of genotypes and alleles of gene HASI (rs11084111) in groups of healthy patients and patients with chronic hepatitis C. The direct relationships are established between hyaluronic acid and markers of cytolysis, cholestasis, alpha-fetoprotein (p = 0.001), viral load (p = 0.003) liver elasticity index according fibroflexography data (p < 0.001) and fibrosis index (p < 0.001). The established relationships indicate association of hepatofibrosis with cytolysis, cholestasis, hepatocytes regeneration and virus activity. The hyaluronic acid permits to stratify minimal expressed fibrosis and also the transition of disease to the stage of cirrhosis. PMID:26031159

  11. 40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Subcategory § 420.96 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR 403.7, any... must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. (a... operations. (b) Hydrochloric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire,...

  12. 40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Subcategory § 420.96 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR 403.7, any... must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. (a... operations. (b) Hydrochloric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire,...

  13. 40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Subcategory § 420.96 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR 403.7, any... must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. (a... operations. (b) Hydrochloric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire,...

  14. 40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Subcategory § 420.96 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR 403.7, any... must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. (a... operations. (b) Hydrochloric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire,...

  15. 40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Subcategory § 420.96 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR 403.7, any... must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. (a) Sulfuric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire, coil. Subpart I Pollutant...

  16. Subcritical hydrothermal pretreatment of olive mill solid waste for biofuel production.

    PubMed

    Abu Tayeh, Hiba; Levy-Shalev, Odelia; Azaizeh, Hassan; Dosoretz, Carlos G

    2016-01-01

    The hydrothermal pretreatment of olive mill solid waste amended with 0.6M organic acids was studied at temperatures between 100 and 170°C. Acetic and formic acids which are endogenous intermediates of hemiacetyl splitting at subcritical conditions were tested. Formic acid, with smaller molecular size and lower pKa, was found to be more effective than acetic in the entire range of temperatures tested. Yield of enzymatic hydrolysis was significantly enhanced (>2 folds) at temperatures above 140°C. Concentration of aldehyde byproducts in the medium increased with temperature and pressure and addition of organic acids, however, the highest concentration detected (ca 1g/L) did not surpass values reported as inhibitory of sugars fermentation to ethanol by either yeast or bacteria. Aldehyde production was more affected by temperature than by acid addition. Concluding, addition of formic acid to hydrothermal pretreatment at relatively mild temperatures (140-170°C) and pressure (10-13 atm) improved saccharification yield while saving energy. PMID:26362463

  17. Biomass shock pretreatment

    DOEpatents

    Holtzapple, Mark T.; Madison, Maxine Jones; Ramirez, Rocio Sierra; Deimund, Mark A.; Falls, Matthew; Dunkelman, John J.

    2014-07-01

    Methods and apparatus for treating biomass that may include introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber. In some aspects, the method may include pretreating the biomass with a chemical before introducing the biomass to the chamber and/or after transferring shocked biomass from the chamber.

  18. Enhanced fermentable sugar production from kitchen waste using various pretreatments.

    PubMed

    Hafid, Halimatun Saadiah; Rahman, Nor'Aini Abdul; Md Shah, Umi Kalsom; Baharudin, Azhari Samsu

    2015-06-01

    The kitchen waste fraction in municipal solid waste contains high organic matter particularly carbohydrate that can contribute to fermentable sugar production for subsequent conversion to bioethanol. This study was carried out to evaluate the influence of single and combination pretreatments of kitchen waste by liquid hot water, mild acid pretreatment of hydrochloric acid (HCl) and sulphuric acid (H2SO4) and enzymatic hydrolysis (glucoamylase). The maximum total fermentable sugar produced after combination pretreatment by 1.5% HCl and glucoamylase consisted of 93.25 g/L glucose, 0.542 g/L sucrose, 0.348 g/L maltose, and 0.321 g/L fructose. The glucose released by the combination pretreatment method was 0.79 g glucose/g KW equivalent to 79% of glucose conversion. The effects of the pre-treatment on kitchen waste indicated that the highest solubilization was 40% by the combination method of 1.5% HCl and glucoamylase. The best combination pre-treatment gave concentrations of lactic acid, acetic acid, and propionic acid of 11.74 g/L, 6.77 g/L, and 1.02 g/L, respectively. The decrease of aliphatic absorbance bands of polysaccharides at 2851 and 2923 cm(-1) and the increase on structures of carbonyl absorbance bands at 1600 cm(-1) reflects the progress of the kitchen waste hydrolysis to fermentable sugars. Overall, 1.5% HCl and glucoamylase treatment was the most profitable process as the minimum selling price of glucose was USD 0.101/g kitchen waste. Therefore, the combination pretreatment method was proposed to enhance the production of fermentable sugar, particularly glucose from kitchen waste as the feedstock for bioethanol production. PMID:25900092

  19. Rapid detection of bacteria in green tea using a novel pretreatment method in a bioluminescence assay.

    PubMed

    Shinozaki, Yohei; Harada, Yasuhiro

    2014-06-01

    Tea is one of the most popular beverages consumed in the world, and green tea has become a popular beverage in Western as well as Asian countries. A novel pretreatment method for a commercial bioluminescence assay to detect bacteria in green tea was developed and evaluated in this study. Pretreatment buffers with pH levels ranging from 6.0 to 9.0 were selected from MES (morpholineethanesulfonic acid), HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid), or Tricine buffers. To evaluate the effect of pretreatment and the performance of the assay, serially diluted cultures of Enterobacter cloacae, Escherichia coli, Bacillus subtilis, and Staphylococcus aureus were tested. The improved methods, which consisted of a pretreatment of the sample in alkaline buffer, significantly decreased the background bioluminescence intensity of green tea samples when compared with the conventional method. Pretreatment with alkaline buffers with pH levels ranging from 8.0 to 9.0 increased the bioluminescence intensities of cultures of E. cloacae and S. aureus. Strong log-linear relationships between the bioluminescence intensities and plate counts emerged for the tested strains. Furthermore, the microbial detection limit was 15 CFU in 500 ml of bottled green tea after an 8-h incubation at 35°C and an assay time of 1 h. The results showed that contaminated samples could be detected within 1 h of operation using our improved bioluminescence assay. This method could be used to test for contamination during the manufacturing process as well as for statistical sampling for quality control. PMID:24853516

  20. Evaluation of hydrotropic pretreatment on lignocellulosic biomass.

    PubMed

    Devendra, Leena P; Kiran Kumar, M; Pandey, Ashok

    2016-08-01

    The production of cellulosic ethanol from biomass is considered as a promising alternative to fossil fuels, providing a sustainable option for fuels production in an environmentally compatible manner. The presence of lignin poses a significant challenge for obtaining biofuels and bioproducts from biomass. Part of that problem involves understanding fundamental aspects of lignin structure which can provide a pathway for the development of improved technologies for biomass conversion. Hydrotropic pretreatment has several attractive features that make it an attractive alternative for biofuel production. This review highlights the recent developments on hydrotropic pretreatment processes for lignocellulosic biomass on a molecular structure basis for recalcitrance, with emphasis on lignin concerning chemical structure, transformation and recalcitrance. The review also evaluates the hydrotropic delignification in comparison to alkaline delignification on lignin reduction and surface coverage by lignin. The effect of hydrotrope pretreatment on enzymatic saccharification has also been discussed. PMID:27013188

  1. 40 CFR 421.96 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... wastewater pollutants in metallurgical acid plant blowdown introduced into a POTW shall not exceed the... GUIDELINES AND STANDARDS NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY Metallurgical Acid Plants Subcategory § 421.96 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any...

  2. Serum Sialic Acid Level Is Significantly Associated with Nonalcoholic Fatty Liver Disease in a Nonobese Chinese Population: A Cross-Sectional Study

    PubMed Central

    Lu, Zhenya; Ma, Han; Xu, Chengfu; Shao, Zhou; Cen, Chao; Li, Youming

    2016-01-01

    Background/Aim. To investigate the association between serum sialic acid (SA) levels and nonalcoholic fatty liver disease (NAFLD) in a nonobese Chinese population. Methods. A cross-sectional study was performed among the 5916 adults who took their annual health examinations at International Health Care Center, The First Affiliated Hospital, College of Medicine, Zhejiang University, from December 2013 to November 2014. Results. A total of 693 (11.71%) subjects fulfilled the diagnostic criteria of NAFLD, and NAFLD patients had significantly higher serum SA levels than controls (P < 0.001). The prevalence of NAFLD was positively associated with serum SA levels (P for trend <0.001). Serum sialic acid levels are significantly associated with features of metabolic syndrome (Ps < 0.01). Multivariate logistic regression analysis showed that serum SA level was significantly associated with risk for NAFLD (odds ratio: 1.018, 95%; confidence interval: 1.007–1.030; P = 0.002). Conclusions. Our results suggest for the first time that NAFLD patients had higher serum SA level than controls, and increased serum SA level is significantly associated with risk for NAFLD in a large nonobese Chinese population. PMID:27042666

  3. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

    PubMed Central

    2013-01-01

    Background Pretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined. Results Pretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity. Conclusions Acidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained

  4. Efficacy of hybrid adsorption/membrane pretreatment for low pressure membrane.

    PubMed

    Malczewska, B; Benjamin, M M

    2016-08-01

    Fouling by natural organic matter (NOM) is a major obstacle when water from natural sources is treated using low-pressure membranes. Prior research by our group has demonstrated that passing natural water through a thin, pre-deposited layer of heated aluminum oxide particles (HAOPs) can remove substantial amounts of NOM from the feed and thereby reduce the fouling rate of downstream membranes. The work reported here explored the technical efficacy of such a pretreatment process under more challenging (and therefore realistic) conditions than reported earlier. Several analytical techniques were applied to the feed and permeate in an attempt to identify the key fouling components. The results demonstrate that a HAOPs layer can be pre-deposited on a stainless steel mesh and then be readily washed off at the end of a filtration cycle with very little irreversible fouling due to residual NOM or HAOPs left on the mesh. In addition, the pretreatment step removes enough foulant to allow a downstream UF membrane to operate at significantly higher fluxes than when conventional pretreatment is applied. HAOPs pretreatment also reduced the formation of chlorinated and brominated trihalomethanes (THM4) by more than 67% and of haloacetic acids (HAA9) by 64%-88% in simulated distribution system (SDS) tests. PMID:27174606

  5. Visualizing Lignin Coalescence and Migration Through Maize Cell Walls Following Thermochemical Pretreatment

    SciTech Connect

    Donohoe, B. S.; Decker, S. R.; Tucker, M. P.; Himmel, M. E.; Vinzant, T. B.

    2008-12-01

    Plant cell walls are composed primarily of cellulose, hemicelluloses, lignins, and pectins. Of these components, lignins exhibit unique chemistry and physiological functions. Although lignins can be used as a product feedstock or as a fuel, lignins are also generally seen as a barrier to efficient enzymatic breakdown of biomass to sugars. Indeed, many pretreatment strategies focus on removing a significant fraction of lignin from biomass to better enable saccharification. In order to better understand the fate of biomass lignins that remain with the solids following dilute acid pretreatment, we undertook a structural investigation to track lignins on and in biomass cell walls. SEM and TEM imaging revealed a range of droplet morphologies that appear on and within cell walls of pretreated biomass; as well as the specific ultrastructural regions that accumulate the droplets. These droplets were shown to contain lignin by FTIR, NMR, antibody labeling, and cytochemical staining. We provide evidence supporting the idea that thermochemical pretreatments reaching temperatures above the range for lignin phase transition cause lignins to coalesce into larger molten bodies that migrate within and out of the cell wall, and can redeposit on the surface of plant cell walls. This decompartmentalization and relocalization of lignins is likely to be at least as important as lignin removal in the quest to improve the digestibility of biomass for sugars and fuels production.

  6. Enhanced Solid-State Biogas Production from Lignocellulosic Biomass by Organosolv Pretreatment

    PubMed Central

    Mirmohamadsadeghi, Safoora; Zamani, Akram; Horváth, Ilona Sárvári

    2014-01-01

    Organosolv pretreatment was used to improve solid-state anaerobic digestion (SSAD) for methane production from three different lignocellulosic substrates (hardwood elm, softwood pine, and agricultural waste rice straw). Pretreatments were conducted at 150 and 180°C for 30 and 60 min using 75% ethanol solution as an organic solvent with addition of sulfuric acid as a catalyst. The statistical analyses showed that pretreatment temperature was the significant factor affecting methane production. Optimum temperature was 180°C for elmwood while it was 150°C for both pinewood and rice straw. Maximum methane production was 152.7, 93.7, and 71.4 liter per kg carbohydrates (CH), which showed up to 32, 73, and 84% enhancement for rice straw, elmwood, and pinewood, respectively, compared to those from the untreated substrates. An inverse relationship between the total methane yield and the lignin content of the substrates was observed. Kinetic analysis of the methane production showed that the process followed a first-order model for all untreated and pretreated lignocelluloses. PMID:25243134

  7. Significant Enrichment of Polyunsaturated Fatty Acids (PUFAs) in the Lipids Extracted by Supercritical CO2 from the Livers of Australian Rock Lobsters (Jasus edwardsii).

    PubMed

    Nguyen, Trung T; Zhang, Wei; Barber, Andrew R; Su, Peng; He, Shan

    2015-05-13

    Australian rock lobster (Jasus edwardsii) liver contains approximately 24.3% (w/w) lipids, which can contain a high amount of polyunsaturated fatty acids (PUFAs). However, this material has been found to be contaminated with arsenic (240 mg/kg) and cadmium (8 mg/kg). The high level of contaminants in the raw material and the large amount of PUFAs in the lipids prove a significant challenge in the extraction of high-quality lipids from this byproduct by conventional methods. Supercritical carbon dioxide (SC-CO2) extraction is a highly promising technology for lipid extraction with advantages including low contamination and low oxidation. The technique was optimized to achieve nearly 94% extraction of lipids relative to conventional Soxhlet extraction in Australian rock lobster liver at conditions of 35 MPa and 50 °C for 4 h. The extracted lipids are significantly enriched in PUFAs at 31.3% of total lipids, 4 times higher than those in the lipids recovered by Soxhlet extraction (7.8%). Specifically, the concentrations of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in SC-CO2 extraction are 7 times higher than those obtained by Soxhlet extraction. Moreover, very small amounts of toxic heavy metals such as lead (Pb), arsenic (As), mercury (Hg), and cadmium (Cd) were detected in the SC-CO2-extracted lipids, 0.5-27 times lower than those in the Soxhlet-extracted lipids, which are 40-200 times lower than the regulatory limit maximum values. The low levels of contaminants and the high proportion of PUFAs (dominated by DHA and EPA) found in the SC-CO2-extracted lipids from Australian rock lobster liver suggest that the material could potentially be used as a valuable source of essential fatty acids for human consumption. PMID:25905456

  8. Evaluation of high solids alkaline pretreatment of rice straw.

    PubMed

    Cheng, Yu-Shen; Zheng, Yi; Yu, Chao Wei; Dooley, Todd M; Jenkins, Bryan M; VanderGheynst, Jean S

    2010-11-01

    Fresh-harvested, air-dried rice straw was pretreated at a water content of 5 g H(2)O/g straw using sodium hydroxide (NaOH) and compared to pretreatment at 10 g H(2)O/g straw by hydrated lime (Ca(OH)(2)). Full factorial experiments including parallel wash-only treatments were completed with both sources of alkali. The experiments were designed to measure the effects of alkaline loading and pretreatment time on delignification and sugar yield upon enzymatic hydrolysis. Reaction temperature was held constant at 95 degrees C for lime pretreatment and 55 degrees C for NaOH pretreatment. The range of delignification was 13.1% to 27.0% for lime pretreatments and was 8.6% to 23.1% for NaOH pretreatments. Both alkaline loading and reaction time had significant positive effects (p < 0.001) on delignification under the design conditions, but only alkaline loading had a significant positive effect on enzymatic hydrolysis. Treatment at higher temperature also improved delignification; delignification with water alone ranged from 9.9% to 14.5% for pretreatment at 95 degrees C, but there was little effect observed at 55 degrees C. Post-pretreatment washing of biomass was not necessary for subsequent enzymatic hydrolysis. Maximum glucose yields were 176.3 mg/g dried biomass (48.5% conversion efficiency of total glucose) in lime-pretreated and unwashed biomass and were 142.3 mg/g dried biomass (39.2% conversion efficiency of total glucose) in NaOH-pretreated and unwashed biomass. PMID:20440580

  9. High titer ethanol production from SPORL-pretreated lodgepole pine by simultaneous enzymatic saccharification and combined fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lodgepole wood chips were pretreated by SPORL at 25% solids loading and 180ºC for 20 min with sulfuric acid and sodium bisulfite charges of 2.2 and 8 wt/wt % on oven dry wood basis, respectively. The pretreated wood chips were disk milled with the pretreatment spent liquor and water and then separa...

  10. Urine Pretreat Injection System

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A new method of introducing the OXONE (Registered Trademark) Monopersulfate Compound for urine pretreat into a two-phase urine/air flow stream has been successfully tested and evaluated. The feasibility of this innovative method has been established for purposes of providing a simple, convenient, and safe method of handling a chemical pretreat required for urine processing in a microgravity space environment. Also, the Oxone portion of the urine pretreat has demonstrated the following advantages during real time collection of 750 pounds of urine in a Space Station design two-phase urine Fan/Separator: Eliminated urine precipitate buildup on internal hardware and plumbing; Minimized odor from collected urine; and Virtually eliminated airborne bacteria. The urine pretreat, as presently defined for the Space Station program for proper downstream processing of urine, is a two-part chemical treatment of 5.0 grams of Oxone and 2.3 ml of H2SO4 per liter of urine. This study program and test demonstrated only the addition of the proper ratio of Oxone into the urine collection system upstream of the Fan/Separator. This program was divided into the following three major tasks: (1) A trade study, to define and recommend the type of Oxone injection method to pursue further; (2) The design and fabrication of the selected method; and (3) A test program using high fidelity hardware and fresh urine to demonstrate the method feasibility. The trade study was conducted which included defining several methods for injecting Oxone in different forms into a urine system. Oxone was considered in a liquid, solid, paste and powered form. The trade study and the resulting recommendation were presented at a trade study review held at Hamilton Standard on 24-25 October 94. An agreement was reached at the meeting to continue the solid tablet in a bag concept which included a series of tablets suspended in the urine/air flow stream. These Oxone tablets would slowly dissolve at a controlled rate

  11. Spectroscopic characterization of titanium 6-4 surfaces after chemical pretreatments

    NASA Technical Reports Server (NTRS)

    Chen, W.; Siriwardane, R.; Wightman, J. P.

    1980-01-01

    Several techniques have been used to study pretreated Ti 6-4 surfaces including scanning electron microscopy (SEM), electron spectroscopy of chemical analysis (ESCA), and, reflectance visibile spectroscopy. Each pretreatment type gives a characteristic surface morphology as seen by SEM. Elemental analysis of the Ti 6-4 surfaces was done using ESCA. Trace residual contaminants from particular chemical pretreatments are identified readily. Reflectance visible spectroscopy using indicator dyes placed on Ti 6-4 surfaces appears to be a feasible approach to establish surface acidity. Differences in surface acidity have been observed using bromthymol blue on Ti 6-4 surfaces pretreated by two different methods.

  12. Hydrothermal pretreatment to prevent scale during liquefaction of certain solid carbonaceous materials

    DOEpatents

    Stone, John B.; Floyd, Frank M.

    1984-01-01

    Scale formation during the liquefaction of lower ranking coals and similar carbonaceous materials is significantly reduced and/or prevented by hydrothermal pretreatment. The said pretreatment is believed to convert the scale-forming components to the corresponding carbonate prior to liquefaction. The said pretreatment is accomplished at a total pressure within the range from about 1000 to about 4400 psia. Temperature during said pretreatment will generally be within the range from about 500.degree. to about 700.degree. F.

  13. Pretreatment of Lignocellulosic Biomass with Low-cost Ionic Liquids.

    PubMed

    Gschwend, Florence J V; Brandt, Agnieszka; Chambon, Clementine L; Tu, Wei-Chien; Weigand, Lisa; Hallett, Jason P

    2016-01-01

    A number of ionic liquids (ILs) with economically attractive production costs have recently received growing interest as media for the delignification of a variety of lignocellulosic feedstocks. Here we demonstrate the use of these low-cost protic ILs in the deconstruction of lignocellulosic biomass (Ionosolv pretreatment), yielding cellulose and a purified lignin. In the most generic process, the protic ionic liquid is synthesized by accurate combination of aqueous acid and amine base. The water content is adjusted subsequently. For the delignification, the biomass is placed into a vessel with IL solution at elevated temperatures to dissolve the lignin and hemicellulose, leaving a cellulose-rich pulp ready for saccharification (hydrolysis to fermentable sugars). The lignin is later precipitated from the IL by the addition of water and recovered as a solid. The removal of the added water regenerates the ionic liquid, which can be reused multiple times. This protocol is useful to investigate the significant potential of protic ILs for use in commercial biomass pretreatment/lignin fractionation for producing biofuels or renewable chemicals and materials. PMID:27583830

  14. Understanding of alkaline pretreatment parameters for corn stover enzymatic saccharification

    PubMed Central

    2013-01-01

    Background Previous research on alkaline pretreatment has mainly focused on optimization of the process parameters to improve substrate digestibility. To achieve satisfactory sugar yield, extremely high chemical loading and enzyme dosages were typically used. Relatively little attention has been paid to reduction of chemical consumption and process waste management, which has proven to be an indispensable component of the bio-refineries. To indicate alkali strength, both alkali concentration in pretreatment solution (g alkali/g pretreatment liquor or g alkali/L pretreatment liquor) and alkali loading based on biomass solids (g alkali/g dry biomass) have been widely used. The dual approaches make it difficult to compare the chemical consumption in different process scenarios while evaluating the cost effectiveness of this pretreatment technology. The current work addresses these issues through pretreatment of corn stover at various combinations of pretreatment conditions. Enzymatic hydrolysis with different enzyme blends was subsequently performed to identify the effects of pretreatment parameters on substrate digestibility as well as process operational and capital costs. Results The results showed that sodium hydroxide loading is the most dominant variable for enzymatic digestibility. To reach 70% glucan conversion while avoiding extensive degradation of hemicellulose, approximately 0.08 g NaOH/g corn stover was required. It was also concluded that alkali loading based on total solids (g NaOH/g dry biomass) governs the pretreatment efficiency. Supplementing cellulase with accessory enzymes such as α-arabinofuranosidase and β-xylosidase significantly improved the conversion of the hemicellulose by 6–17%. Conclusions The current work presents the impact of alkaline pretreatment parameters on the enzymatic hydrolysis of corn stover as well as the process operational and capital investment costs. The high chemical consumption for alkaline pretreatment technology

  15. Effect of hydrothermal pretreatment on properties of bio-oil produced from fast pyrolysis of eucalyptus wood in a fluidized bed reactor.

    PubMed

    Chang, Sheng; Zhao, Zengli; Zheng, Anqing; Li, Xiaoming; Wang, Xiaobo; Huang, Zhen; He, Fang; Li, Haibin

    2013-06-01

    Eucalyptus wood powder was first subjected to hydrothermal pretreatment in a high-pressure reactor at 160-190°C, and subsequently fast pyrolyzed in a fluidized bed reactor at 500°C to obtain high quality bio-oil. This study focused on investigating effect of hydrothermal pretreatment on bio-oil properties. Hemicellulose and some metals were effectively removed from eucalyptus wood, while cellulose content was enhanced. No significant charring and carbonization of constituents was observed during hydrothermal pretreatment. Thus pretreated eucalyptus wood gave higher bio-oil yield than original eucalyptus wood. Chemical composition of bio-oil was examined by GC/MS and (13)C NMR analyses. Bio-oil produced from pretreated eucalyptus wood exhibited lower contents of ketones and acids, while much higher levoglucosan content than bio-oil produced from original eucalyptus wood, which would help to improve thermal stability of bio-oil and extract levoglucosan from bio-oil. Hydrothermal pretreatment also improved bio-oil fuel quality through lowering water content and enhancing heating value. PMID:23624050

  16. Electrolytic pretreatment of urine

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Electrolysis has been under evaluation for several years as a process to pretreat urine for ultimate recovery of potable water in manned spacecraft applications. The conclusions that were drawn from this investigation are the following: (1) A platinum alloy containing 10 percent rhodium has been shown to be an effective, corrosion-resistant anode material for the electrolytic pretreatment of urine. Black platinum has been found to be suitable as a cathode material. (2) The mechanism of the reactions occurring during the electrolysis of urine is two-stage: (a) a total Kjeldahl nitrogen and total organic carbon (TOC) removal in the first stage is the result of electrochemical oxidation of urea to CO2, H2O, and ammonia followed by chloride interaction to produce N2 from ammonia, (b) after the urea has been essentially removed and the chloride ions have no more ammonia to interact with, the chloride ions start to oxidize to higher valence states, thus producing perchlorates. (3) Formation of perchlorates can be suppressed by high/low current operation, elevated temperature, and pH adjustment. (4) UV-radiation showed promise in assisting electrolytic TOC removal in beaker tests, but was not substantiated in limited single cell testing. This may have been due to non-optimum configurations of the single cell test rig and the light source.

  17. Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

    NASA Astrophysics Data System (ADS)

    Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

    The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

  18. Impact of thermal pretreatment on the fast pyrolysis conversion of Southern Pine

    SciTech Connect

    Tyler L. Westover; Manunya Phanphanich; Micael L. Clark; Sharna R. Rowe; Steven E. Egan; Christopher T Wright; Richard D. Boardman; Alan H. Zacher

    2013-01-01

    Background: Thermal pretreatment of biomass ranges from simple (nondestructive) drying to more severe treatments that cause devolatization, depolymerization and carbonization. These pretreatments have demonstrated promise for transforming raw biomass into feedstock material that has improved milling, handling, storage and conversion properties. In this work, southern pine material was pretreated at 120, 180, 230 and 270 degrees C, and then subjected to pyrolysis tests in a continuous-feed bubbling-fluid bed pyrolysis system. Results: High pretreatment temperatures were associated with lower specific grinding energies, higher grinding rates and lower hydrogen and oxygen contents. Higher pretreatment temperatures were also correlated with increased char production, decreased total acid number and slight decrease in the oxygen content of the pyrolysis liquid fraction. Conclusion: Thermal pretreatment has both beneficial and detrimental impacts on fast pyrolysis conversion of pine material to bio-oil, and the effect of thermal pretreatment on upgrading of pyrolysis bio-oil requires further attention.

  19. Enhancing methane production of Chlorella vulgaris via thermochemical pretreatments.

    PubMed

    Mendez, Lara; Mahdy, Ahmed; Timmers, Rudolphus A; Ballesteros, Mercedes; González-Fernández, Cristina

    2013-12-01

    To enhance the anaerobic digestion of Chlorella vulgaris, thermochemical pretreatments were conducted. All pretreatments markedly improved solubilisation of carbohydrates. Thermal treatments and thermal treatments combined with alkali resulted in 5-fold increase of soluble carbohydrates while thermal treatment with acid addition enhanced by 7-fold. On the other hand, proteins were only solubilized with thermo-alkaline conditions applied. Likewise, all the pretreatments tested improved methane production. Highest anaerobic digestion was accomplished by thermal treatment at 120°C for 40 min without any chemical addition. As a matter of fact, hydrolysis constant rate was doubled under this condition. According to the energetic analysis, energy input was higher than the extra energy gain at the solid concentration employed. Nevertheless, higher biomass organic load pretreatment may be an option to achieve positive energetic balances. PMID:24096280

  20. Effect of moisture on pretreatment efficiency for anaerobic digestion of lignocellulosic substrates.

    PubMed

    Peces, M; Astals, S; Mata-Alvarez, J

    2015-12-01

    The present study evaluates the effect of moisture in low-temperature and ultrasound pretreatment on lignocellulosic substrates anaerobic biodegradability, where brewer's spent grain was used as model substrate. Besides moisture content, low-temperature pretreatment was also evaluated in terms of temperature (60-80°C) and exposure time (12-72 h). Likewise, ultrasonication was also evaluated in terms of specific energy (1000-50,000 kJ kg TS(-1)). In addition, the effect of substrate particle size reduction by milling pretreatment was also considered. The results clearly demonstrated that substrate moisture (total solid concentration) is a significant parameter for pretreatment performance, although it has been rarely considered in pretreatment optimisation. Specifically, moisture optimisation increased the methane yield of brewer's spent grain by 6% for low-temperature pretreatment (60°C), and by 14% for ultrasound pretreatment (1000 kJ kg TS(-1)) towards the control (without pretreatment). In both pretreatments, the experimental optimum total solid concentration was 100 gTS kg(-1). Thus, lowering substrate moisture, a strategy suggested attaining energetic pretreatment feasibility, needs to be analysed as another pretreatment variable since it might have limited correlation. Finally, a preliminary energetic balance of the pretreatments under study showed that the extra methane production could not cover the energetic pretreatment expenses. PMID:26316102

  1. Effects of sodium nitroprusside (SNP) pretreatment on UV-B stress tolerance in lettuce (Lactuca sativa L.) seedlings.

    PubMed

    Esringu, Aslıhan; Aksakal, Ozkan; Tabay, Dilruba; Kara, Ayse Aydan

    2016-01-01

    Ultraviolet-B (UV-B) radiation is one of the most important abiotic stress factors that could influence plant growth, development, and productivity. Nitric oxide (NO) is an important plant growth regulator involved in a wide variety of physiological processes. In the present study, the possibility of enhancing UV-B stress tolerance of lettuce seedlings by the exogenous application of sodium nitroprusside (SNP) was investigated. UV-B radiation increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and total phenolic concentrations, antioxidant capacity, and expression of phenylalanine ammonia lyase (PAL) gene in seedlings, but the combination of SNP pretreatment and UV-B enhanced antioxidant enzyme activities, total phenolic concentrations, antioxidant capacity, and PAL gene expression even more. Moreover, UV-B radiation significantly inhibited chlorophylls, carotenoid, gibberellic acid (GA), and indole-3-acetic acid (IAA) contents and increased the contents of abscisic acid (ABA), salicylic acid (SA), malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide radical (O2•(-)) in lettuce seedlings. When SNP pretreatment was combined with the UV-B radiation, we observed alleviated chlorophylls, carotenoid, GA, and IAA inhibition and decreased content of ABA, SA, MDA, H2O2, and O2•(-) in comparison to non-pretreated stressed seedlings. PMID:26330324

  2. Effect of pretreatment with carbon monoxide and ozone on the quality of vacuum packaged beef meats.

    PubMed

    Lyu, Fei; Shen, Kejing; Ding, Yuting; Ma, Xin

    2016-07-01

    Beef meats without pretreatment (CK) or pretreated with different volume ratios of carbon monoxide and ozone of 100%CO (T1), 2%O3+98%CO (T2), 5%O3+95%CO (T3) and 10%O3+90%CO (T4) using modified atmosphere packages for 1.5h, after that they were vacuum-packaged and stored in 0°C refrigerator for 46days. The surface color a* values and sensory scores of T1, T2, T3 and T4 were significant higher than CK (p<0.05) during storage. In the mid and later storage, the drip loss, total viable counts (TVC), metmyoglobin (met-Mb), thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N) and pH of T1, T2, T3 and T4 were significantly lower than CK (p<0.05), and these values of T2, T3 and T4 were significantly lower than T1 in the later storage. In conclusion, O3 in the combination didn't affect the color-developing effect of CO, and could help CO maintain the meat quality. Therefore, the pretreatment of CO combined with O3 at certain concentrations can be a promising technique to maintain the quality of beef meats. PMID:26971310

  3. Effect of enzymatic pretreatment of various lignocellulosic substrates on production of phenolic compounds and biomethane potential.

    PubMed

    Schroyen, Michel; Vervaeren, Han; Vandepitte, Hanne; Van Hulle, Stijn W H; Raes, Katleen

    2015-09-01

    Pretreatment of lignocellulosic biomass is necessary to enhance the hydrolysis, which is the rate-limiting step in biogas production. Laccase and versatile peroxidase are enzymes known to degrade lignin. Therefore, the impact of enzymatic pretreatment was studied on a variety of biomass. A significant higher release in total phenolic compounds (TPC) was observed, never reaching the inhibiting values for anaerobic digestion. The initial concentration of TPC was higher in the substrates containing more lignin, miscanthus and willow. The anaerobic digestion of these two substrates resulted in a significant lower biomethane production (68.8-141.7 Nl/kg VS). Other substrates, corn stover, flax, wheat straw and hemp reached higher biomethane potential values (BMP), between 241 and 288 Nl/kg VS. Ensilaged maize reached 449 Nl/kg VS, due to the ensilation process, which can be seen as a biological and acid pretreatment. A significant relation (R(2) = 0.89) was found between lignin content and BMP. PMID:26094196

  4. Steam Cooking Significantly Improves In Vitro Bile Acid Binding of Collard Greens, Kale, Mustard Greens, Broccoli, Green Bell Pepper and Cabbage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bile acid binding capacity has been related to the cholesterol-lowering potential of foods and food fractions. Lowering recirculating bile acids results in utilization of cholesterol to synthesize bile acid and reduced fat absorption. Secondary bile acids have been associated with increasing the r...

  5. Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Corredor, Deisy Y.

    The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis

  6. Effect of ultrasound pre-treatment of hemp (Cannabis sativa L.) seed on supercritical CO2 extraction of oil.

    PubMed

    Da Porto, C; Natolino, A; Decorti, D

    2015-03-01

    Ultrasound pre-treatment of intact hemp seeds without any solvent assistance was carried out for 10, 20 and 40 min prior to SCCO2 extraction at 40 °C, 300 bar and 45 kg CO2/kg feed. Sonication time effect on SC-CO2 extraction was investigated by the extraction kinetics. The maximum extraction yield was estimated to be 24.03 (% w/w) after 10 min of ultrasonic pre-treatment. The fatty acid compositions of the oils extracted by SC-CO2 without and with ultrasound pre-treatments was analyzed using gas chromatography. It was shown that the content of linoleic, α-linolenic and oleic acids (the most abundant unsaturated fatty acids) of the hemp seed oils were not affected significantly by the application of ultrasound. UV spectroscopy indices (K232 and K268) and antiradical capacity were used to follow the quality of oils. Significant were the changes in their antiradical capacity due to ultrasound treatment. A comparison with the oil extracted by Soxhlet was also given. PMID:25745251

  7. Degradation of Methoxylated Benzoic Acids by a Nocardia from a Lignin-Rich Environment: Significance to Lignin Degradation and Effect of Chloro Substituents

    PubMed Central

    Crawford, R. L.; McCoy, Elizabeth; Harkin, J. M.; Kirk, T. K.; Obst, J. R.

    1973-01-01

    Strain A81 of Nocardia corallina hydroxylates or demethylates p-anisic acid to p-hydroxybenzoic acid and isovanillic acid. It demethylates veratric acid to a mixture of vanillic and isovanillic acids. These are both demethylated to protocatechuic acid, which undergoes ring cleavage to afford β-carboxy-cis-cis-muconic acid. The intermediacy of protocatechuic acid in the catabolic pathway of veratric acid was confirmed by blocking ring cleavage with an additional substituent in the ring: 5-chlorovanillic acid was demethylated to 5-chloro-protocatechuic acid, which accumulated. Chloro substituents in the ring of other methoxylated benzoic acids also arrested their normal metabolism by the Nocardia: an ortho-chloro substituent thwarted both demethylation and ring-opening. ortho-Hydroxylation of p-methoxybenzoic acid to isovanillic acid was unaffected by a chlorine ortho to the methoxyl group. Washed whole cells of veratric acid-grown N. corallina A81 produced no detected structural changes in an isolated lignin. The implications of this observation are discussed. PMID:4743871

  8. An industry perspective on the use of “atoxigenic” strains of Aspergillus flavus as biological control agents and the significance of cyclopiazonic acid

    PubMed Central

    King, Eileen D; (Bobby) Bassi, Albeit B; Ross, David C; Druebbisch, Bernd

    2011-01-01

    Several nonaflatoxigenic strains of Aspergillus flavus have been registered in the United States to reduce aflatoxin accumulation in maize and other crops, but there may be unintended negative consequences if these strains produce cyclopiazonic acid (CPA). AF36, a nonaflatoxigenic, CPA-producing strain has been shown to produce CPA in treated maize and peanuts. Alternative strains, including Afla-Guard® brand biocontrol agent and K49, do not produce CPA and can reduce both aflatoxin and CPA in treated crops. Chronic toxicity of CPA has not been studied, and recent animal studies show significant harmful effects from short-term exposure to CPA at low doses. Grower and industry confidence in this approach must be preserved through transparency. PMID:22844262

  9. Improvement of sugar yields from corn stover using sequential hot water pretreatment and disk milling.

    PubMed

    Kim, Sun Min; Dien, Bruce S; Tumbleson, M E; Rausch, Kent D; Singh, Vijay

    2016-09-01

    Efficient pretreatment is essential for economic conversion of lignocellulosic feedstocks into monosaccharides for biofuel production. To realize high sugar yields with low inhibitor concentrations, hot water or dilute acid pretreatment followed by disk milling is proposed. Corn stover at 20% solids was pretreated with hot water at 160-200°C for 4-8min with and without subsequent milling. Hot water pretreatment and disk milling acted synergistically to improve glucose and xylose yields by 89% and 134%, respectively, compared to hot water pretreatment alone. Hot water pretreated (180°C for 4min) and milled samples had the highest glucose and xylose yields among all hot water pretreated and milled samples, which were comparable to samples pretreated with 0.55% dilute acid at 160°C for 4min. However, samples pretreated with 1% dilute acid at 150°C for 4min and disk milled had the highest observed glucose (87.3%) and xylose yields (83.4%). PMID:27289063

  10. Sensitized photolysis as pretreatment to biological degradation of trichlorobenzenes

    SciTech Connect

    Kim, Jae Hyoun.

    1991-01-01

    The role of photolysis as pretreatment process was examined for the biological degradation of trichlorobenzenes (TCBs), namely 1,2,3-, 1,2,4- and 1,3,5-trichlorobenzenes. Initially, direct and indirect photolysis experiments were conducted using aqueous solutions with 1% acetonitrile of the three isomers of trichlorobenzenes with and without sensitizers. The sensitizers used were Fenton's reagent, nitrite, triethylamine, humic acid and TiO{sub 2}. The photochemical experiments were performed using laboratory simulated sunlight and the kinetic rates for these processes were calculated. The effect of photolysis on the biological degradation chlorobenzenes were examined using a chemical activation system (CAS) which consists of EDTA, ferrous sulfate, ascorbic acid, catalase and H{sub 2}O{sub 2} in potassium phosphate buffer (monobasic) and a primary sewage effluent. Initially, kinetic rates by CAS biodegradation and primary sewage were obtained and compared. In general, the rates of biodegradation were greater in the test media with catalase. The rate of transformation in CAS was enhanced in the order: monoCB < 1,2,3-TCB < 1,2,4-TCB < 1,3,5-TCB; whereas, when CAS was used as a control, the kinetic rates in the presence of catalase increased in the sequence: 1,2,3-TCB, 1,3,5-TCB < 1,2,4-TCB < MonoCB. Photolysis studied in concert with the biological systems showed significant enhancement of the degradation rate of trichlorobenzenes. The photolysis rates were higher for those with sensitized photolysis. This study shows that photolysis can be used as a pretreatment of enhancing biodegradation of trichlorobenzenes in aqueous systems.

  11. Impact of pretreatments on morphology and enzymatic saccharification of shedding bark of Melaleuca leucadendron.

    PubMed

    Ahmed, Ibrahim Nasser; Santoso, Shella Permatasari; Tran-Nguyen, Phuong Lan; Huynh, Lien Huong; Ismadji, Suryadi; Ju, Yi-Hsu

    2013-07-01

    The effects of subcritical water (SCW) and dilute acid pretreatments on the shedding bark of Melaleuca leucadendron (paper bark tree, PBT) biomass morphology, crystallinity index (CrI) and enzymatic saccharification were studied. The morphology of PBT bark was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. SCW pretreatment mainly extracted amorphous parts of the biomass hence its CrI increased, partial decrystallization of cellulose and exposing of intact nanofibers of cellulose were observed for SCW pretreatment at 180°C. On the other hand, dilute acid pretreatment at 160°C exhibited a large decrease in CrI, an increase in surface area, a decrease in lignin content and decrystallization of cellulose as well as the peel-off and degradation of some nanofiber bundles. Dilute acid and SCW pretreatments of PBT biomass resulted in about 4.5 fold enhancement in glucose release relative to the untreated one. PMID:23697662

  12. Effect of thermal hydrolysis pre-treatment on anaerobic digestion of municipal biowaste: a pilot scale study in China.

    PubMed

    Zhou, Yingjun; Takaoka, Masaki; Wang, Wei; Liu, Xiao; Oshita, Kazuyuki

    2013-07-01

    Co-digestion of wasted sewage sludge, restaurant kitchen waste, and fruit-vegetable waste was carried out in a pilot plant with thermal hydrolysis pre-treatment. Steam was used as heat source for thermal hydrolysis. It was found 38.3% of volatile suspended solids were dissolved after thermal hydrolysis, with digestibility increased by 115%. These results were more significant than those from lab studies using electricity as heat source due to more uniform heating. Anaerobic digesters were then operated under organic loading rates of about 1.5 and 3 kg VS/(m³ d). Little difference was found for digesters with and without thermal pre-treatment in biogas production and volatile solids removal. However, when looking into the digestion process, it was found digestion rate was almost doubled after thermal hydrolysis. Digester was also more stable with thermal hydrolysis pre-treatment. Less volatile fatty acids (VFAs) were accumulated and the VFAs/alkalinity ratio was also lower. Batch experiments showed the lag phase can be eliminated by thermal pre-treatment, implying the advantage could be more significant under a shorter hydraulic retention time. Moreover, it was estimated energy cost for thermal hydrolysis can be partly balanced by decreasing viscosity and improving dewaterability of the digestate. PMID:23419457

  13. Cellulolytic Enzymes Production via Solid-State Fermentation: Effect of Pretreatment Methods on Physicochemical Characteristics of Substrate

    PubMed Central

    Brijwani, Khushal; Vadlani, Praveen V.

    2011-01-01

    We investigated the effect of pretreatment on the physicochemical characteristics—crystallinity, bed porosity, and volumetric specific surface of soybean hulls and production of cellulolytic enzymes in solid-state fermentation of Trichoderma reesei and Aspergillus oryzae cultures. Mild acid and alkali and steam pretreatments significantly increased crystallinity and bed porosity without significant change inholocellulosic composition of substrate. Crystalline and porous steam-pretreated soybean hulls inoculated with T. reesei culture had 4 filter paper units (FPU)/g-ds, 0.6 IU/g-ds β-glucosidase, and 45 IU/g-ds endocellulase, whereas untreated hulls had 0.75 FPU/g-ds, 0.06 IU/g-ds β-glucosidase, and 7.29 IU/g-ds endocellulase enzyme activities. In A. oryzae steam-pretreated soybean hulls had 47.10 IU/g-ds endocellulase compared to 30.82 IU/g-ds in untreated soybean hulls. Generalized linear statistical model fitted to enzyme activity data showed that effects of physicochemical characteristics on enzymes production were both culture and enzyme specific. The paper shows a correlation between substrate physicochemical properties and enzyme production. PMID:21755043

  14. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    DOE PAGESBeta

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; Huang, Fang; Pu, Yunqiao; Ragauskas, Arthur J.

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and themore » DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.« less

  15. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize (Zea mays L.) lines

    PubMed Central

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; Williams, Daniel L.; Magee, Timothy D.; Kaeppler, Shawn M.; de Leon, Natalia; Hodge, David B.

    2015-01-01

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall susceptibility to swelling. It was also positively correlated with the lignin syringyl/guaiacyl ratio and negatively correlated with the initial cell-wall lignin, xylan, acetate, and p-coumaric acid (pCA) content, as well as pCA released from the cell wall by pre-treatment. The hydrolysis yield following pre-treatment exhibited statistically significant negative correlations to the lignin content after pre-treatment and positive correlations to the solubilized ferulic acid and pCA. Several unanticipated results were observed, including a positive correlation between initial lignin and acetate content, lack of correlation between acetate content and initial xylan content, and negative correlation between each of these three variables to the hydrolysis yields for untreated maize. Another surprising result was that pCA release was negatively correlated with hydrolysis yields for untreated maize and, along with ferulic acid release, was positively correlated with the pre-treated maize hydrolysis yields. This indicates that these properties that may negatively contribute to the recalcitrance in untreated cell walls may positively contribute to their deconstruction by alkaline pre-treatment. PMID:25871649

  16. 40 CFR 420.95 - Pretreatment standards for existing sources (PSES).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Subcategory § 420.95 Pretreatment standards for existing sources (PSES). Except as provided in 40 CFR 403.7... owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards... to each fume scrubber associated with sulfuric acid pickling operations. (b) Hydrochloric...

  17. 40 CFR 420.95 - Pretreatment standards for existing sources (PSES).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Subcategory § 420.95 Pretreatment standards for existing sources (PSES). Except as provided in 40 CFR 403.7... owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards... to each fume scrubber associated with sulfuric acid pickling operations. (b) Hydrochloric...

  18. 40 CFR 420.95 - Pretreatment standards for existing sources (PSES).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Subcategory § 420.95 Pretreatment standards for existing sources (PSES). Except as provided in 40 CFR 403.7... owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards... to each fume scrubber associated with sulfuric acid pickling operations. (b) Hydrochloric...

  19. 40 CFR 420.95 - Pretreatment standards for existing sources (PSES).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Subcategory § 420.95 Pretreatment standards for existing sources (PSES). Except as provided in 40 CFR 403.7... owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards... to each fume scrubber associated with sulfuric acid pickling operations. (b) Hydrochloric...

  20. 40 CFR 415.86 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Hydrofluoric Acid Production Subcategory § 415.86 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR... treatment works must comply with 40 CFR part 403 and achieve the following Pretreatment Standards for...

  1. 40 CFR 415.86 - Pretreatment standards for new sources (PSNS).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Hydrofluoric Acid Production Subcategory § 415.86 Pretreatment standards for new sources (PSNS). Except as provided in 40 CFR... treatment works must comply with 40 CFR part 403 and achieve the following Pretreatment Standards for...

  2. The bovine fatty acid binding protein 4 gene is significantly associated with marbling and subcutaneous fat depth in Wagyu x Limousin F2 crosses.

    PubMed

    Michal, J J; Zhang, Z W; Gaskins, C T; Jiang, Z

    2006-08-01

    Fatty acid binding protein 4 (FABP4), which is expressed in adipose tissue, interacts with peroxisome proliferator-activated receptors and binds to hormone-sensitive lipase and therefore, plays an important role in lipid metabolism and homeostasis in adipocytes. The objective of this study was to investigate associations of the bovine FABP4 gene with fat deposition. Both cDNA and genomic DNA sequences of the bovine gene were retrieved from the public databases and aligned to determine its genomic organization. Primers targeting two regions of the FABP4 gene were designed: from nucleotides 5433-6106 and from nucleotides 7417-7868 (AAFC01136716). Direct sequencing of polymerase chain reaction (PCR) products on two DNA pools from high- and low-marbling animals revealed two single nucleotide polymorphisms (SNPs): AAFC01136716.1:g.7516G>C and g.7713G>C. The former SNP, detected by PCR-restriction fragment length polymorphism using restriction enzyme MspA1I, was genotyped on 246 F2 animals in a Waygu x Limousin F2 reference population. Statistical analysis showed that the FABP4 genotype significantly affected marbling score (P = 0.0398) and subcutaneous fat depth (P = 0.0246). The FABP4 gene falls into a suggestive/significant quantitative trait loci interval for beef marbling that was previously reported on bovine chromosome 14 in three other populations. PMID:16879357

  3. Inoculum pre-treatment affects the fermentative activity of hydrogen-producing communities in the presence of 5-hydroxymethylfurfural.

    PubMed

    Bellucci, Micol; Botticella, Giuseppe; Francavilla, Matteo; Beneduce, Luciano

    2016-01-01

    To enhance the productivity of mixed microbial cultures for fermentative bio-hydrogen production, chemical-physical pre-treatments of the original seed are needed to suppress the activity of hydrogen (H2)-consuming microbes. This approach might influence negatively the composition and diversity of the hydrogen-producing community with consequences on the functional stability of the H2-producing systems in case of perturbations. In this study, we aimed at investigating the effect of different types of pre-treatment on the performance of hydrogen production systems in the presence of an inhibitor, such as 5-hydroxymethylfurfural (HMF). The efficiency and the microbial community structure of batch reactors amended with HMF and inoculated with non-pretreated and pretreated (acid, heat shock, and aeration) anaerobic sludge were evaluated and compared with control systems. The type of pre-treatments influenced the microbial community assembly and activity in inhibited systems, with significant effect on the performance. Cumulative H2 production tests showed that the pre-aerated systems (control and HMF inhibited) were the most efficient, while the difference of the lag phase of the pre-acidified control and HMF-added test was negligible. Analyses of the structure of the enriched microbial community in the systems through PCR-denaturing gradient gel electrophoresis (DGGE) followed by band sequencing revealed that the differences in performance were mostly related to shifts in the metabolic pathways rather than in the predominant species. In conclusion, the findings suggest that the use of specific inoculum pre-treatment could contribute to regulate the metabolic activity of the fermentative H2-producing bacteria in order to enhance the bio-energy production. PMID:26428244

  4. Natural deep eutectic solvent mediated pretreatment of rice straw: bioanalytical characterization of lignin extract and enzymatic hydrolysis of pretreated biomass residue.

    PubMed

    Kumar, Adepu K; Parikh, Bhumika S; Pravakar, Mohanty

    2016-05-01

    The present investigation demonstrated pretreatment of lignocellulosic biomass rice straw using natural deep eutectic solvents (NADESs), and separation of high-quality lignin and holocellulose in a single step. Qualitative analysis of the NADES extract showed that the extracted lignin was of high purity (>90 %), and quantitative analysis showed that nearly 60 ± 5 % (w/w) of total lignin was separated from the lignocellulosic biomass. Addition of 5.0 % (v/v) water during pretreatment significantly enhanced the total lignin extraction, and nearly 22 ± 3 % more lignin was released from the residual biomass into the NADES extract. X-ray diffraction studies of the untreated and pretreated rice straw biomass showed that the crystallinity index ratio was marginally decreased from 46.4 to 44.3 %, indicating subtle structural alterations in the crystalline and amorphous regions of the cellulosic fractions. Thermogravimetric analysis of the pretreated biomass residue revealed a slightly higher T dcp (295 °C) compared to the T dcp (285 °C) of untreated biomass. Among the tested NADES reagents, lactic acid/choline chloride at molar ratio of 5:1 extracted maximum lignin of 68 ± 4 mg g(-1) from the rice straw biomass, and subsequent enzymatic hydrolysis of the residual holocellulose enriched biomass showed maximum reducing sugars of 333 ± 11 mg g(-1) with a saccharification efficiency of 36.0 ± 3.2 % in 24 h at 10 % solids loading. PMID:26032452

  5. Avian serum. cap alpha. /sub 1/-glycoprotein, hemopexin, differing significantly in both amino acid and carbohydrate composition from mammalian (. beta. -glycoprotein) counter parts

    SciTech Connect

    Goldfarb, V.; Trimble, R.B.; Falco, M.D.; Liem, H.H.; Metcalfe, S.A.; Wellner, D.; Muller-Eberhard, U.

    1986-10-21

    The physicochemical characteristics of chicken hemopexin, which can be isolated by heme-agarose affinity chromatography, is compared with representative mammalian hemopexins of rat, rabbit, and human. The avian polypeptide chain appears to be slightly longer (52 kDa) than the human, rat, or rabbit forms (49 kDa), and also the glycoprotein differs from the mammalian hemopexins in being an ..cap alpha../sub 1/-glycoprotein instead of a ..beta../sub 1/-glycoprotein. The distinct electrophoretic mobility probably arises from significant differences in the amino acid composition of the chicken form, which, although lower in serine and particularly in lysine, has a much higher glutamine/glutamate and agrinine content, and also a higher proline, glycine, and histidine content, than the mammalian hemopexins. Compositional analyses and /sup 125/I concanavalin A and /sup 125/I wheat germ agglutinin binding suggest that chicken hemopexin has a mixture of three fucose-free N-linked bi- and triantennary oligosaccharides. In contrast, human hemopexin has give N-linked oligosaccharides and an additional O-linked glycan blocking the N-terminal threonine residue, while the rabbit form has four N-linked oligosaccharides. In keeping with the finding of a simpler carbohydrate structure, the avian hemopexin shows only a single band on polyacrylamide gel electrophoresis under both nondenaturing and denaturing conditions, whereas the hemopexins of the three mammalian species tested show several bands. In contrast, the isoelectric focusing pattern of chicken hemopexin is very complex, revealing at least nine bands between pH 4.0 and pH band 5.0, while the other hemopexins show a broad smear of multiple ill-defined bands in the same region.Results indicate the hemopexin of avians differs substantially from the hemopexins of mammals, which show a notable similarity with regard to carbohydrate structure and amino acid composition.

  6. Bioethanol production from rice straw by popping pretreatment

    PubMed Central

    2013-01-01

    Background Rice straw has considerable potential as a raw material for bioethanol production. Popping pretreatment of rice straw prior to downstream enzymatic hydrolysis and fermentation was found to increase cellulose to glucose conversion efficiency. The aim of this study was to investigate the influence of popping pretreatment and determine the optimal enzyme loading using a surface response design. Results The optimal doses of cellulase and xylanase enzymes were 23 FPU and 62 IU/g biomass, respectively. Using the optimized enzyme condition and popping pretreatment of rice straw (15% substrate loading, w/v), a sugar recovery of 0.567 g/g biomass (glucose; 0.394 g/g) was obtained in 48 h, which was significantly higher than that from untreated rice straw (total sugar recovery; 0.270 g/g biomass). Fermentation of the hydrolyzates by Saccharomyces cerevisiae resulted in 0.172 g ethanol/g biomass after 24 h, equivalent to 80.9% of the maximum theoretical yield (based on the amount of glucose in raw material). Changes in the chemical composition and surface area of rice straw were also investigated before and after popping pretreatment. The results showed little or no difference in chemical composition between the pretreated rice straw and the control. However, the surface area of pretreated rice straw increased twofold compared to the control. Conclusion Popping pretreatment of rice straw can effectively improve downstream saccharification and fermentation, important for bioethanol production. PMID:24286244

  7. Harnessing the potential of ligninolytic enzymes for lignocellulosic biomass pretreatment.

    PubMed

    Masran, Ruqayyah; Zanirun, Zuraidah; Bahrin, Ezyana Kamal; Ibrahim, Mohamad Faizal; Lai Yee, Phang; Abd-Aziz, Suraini

    2016-06-01

    Abundant lignocellulosic biomass from various industries provides a great potential feedstock for the production of value-added products such as biofuel, animal feed, and paper pulping. However, low yield of sugar obtained from lignocellulosic hydrolysate is usually due to the presence of lignin that acts as a protective barrier for cellulose and thus restricts the accessibility of the enzyme to work on the cellulosic component. This review focuses on the significance of biological pretreatment specifically using ligninolytic enzymes as an alternative method apart from the conventional physical and chemical pretreatment. Different modes of biological pretreatment are discussed in this paper which is based on (i) fungal pretreatment where fungi mycelia colonise and directly attack the substrate by releasing ligninolytic enzymes and (ii) enzymatic pretreatment using ligninolytic enzymes to counter the drawbacks of fungal pretreatment. This review also discusses the important factors of biological pretreatment using ligninolytic enzymes such as nature of the lignocellulosic biomass, pH, temperature, presence of mediator, oxygen, and surfactant during the biodelignification process. PMID:27115758

  8. Lime pretreatment and fermentation of enzymatically hydrolyzed sugarcane bagasse.

    PubMed

    Rabelo, Sarita C; Maciel Filho, Rubens; Costa, Aline C

    2013-03-01

    Sugarcane bagasse was subjected to lime (calcium hydroxide) pretreatment and enzymatic hydrolysis for second-generation ethanol production. A central composite factorial design was performed to determine the best combination of pretreatment time, temperature, and lime loading, as well as to evaluate the influence of enzymatic loadings on hydrolysis conversion. The influence of increasing solids loading in the pretreatment and enzymatic hydrolysis stages was also determined. The hydrolysate was fermented using Saccharomyces cerevisiae in batch and continuous mode. In the continuous fermentation, the hydrolysates were concentrated with molasses. Lime pretreatment significantly increased the enzymatic digestibility of sugarcane bagasse without the need for prior particle size reduction. In the optimal pretreatment conditions (90 h, 90 °C, 0.47 glime/g bagasse) and industrially realistic conditions of hydrolysis (12.7 FPU/g of cellulase and 7.3 CBU/g of β-glucosidase), 139.6 kglignin/ton raw bagasse and 126.0 kg hemicellulose in the pretreatment liquor per ton raw bagasse were obtained. The hydrolysate from lime pretreated sugarcane bagasse presented low amounts of inhibitors, leading to ethanol yield of 164.1 kgethanol/ton raw bagasse. PMID:23334836

  9. Centralized industrial waste pretreatment

    SciTech Connect

    Palmer, L.H.; Cunningham, D.P.

    1991-11-01

    Four years ago, the Sanitary District of Washington County, Maryland asked the Economic Development Commission and the elected officials what if' the district researched the potential for a centralized industrial waste treatment facility for the county. The reason: about a dozen privately and publicly owned industrial parks cover almost 809 ha (2,000 ac) of Washington County. Most of them opened during the 1980s and all of them are within minutes of two superhighways. The county, which has 120,000 residents, is also home to 20 trucking companies and the main lines of CSX, Conrail, and Norfolk Southern, the largest railroads east of the Mississippi River. The county is home to Mack Trucks Engine and Transmissions facility, Rohr Industries (formally Fairchild Industries), Citicorp Credit Services, Rust-Oleum, Certain-teed PVC products, and many more. Because the county has a strong economic base, reasonable property taxes, and an exceptionally clean environment, the idea for an industrial pretreatment facility was met with enthusiasm from both parties and, therefore, the idea became a concept for planning in winter 1987-88. Plans for serving targeted industries and for isolating and controlling individual wastes discharges are discussed.

  10. 40 CFR 418.56 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Pretreatment standards for new sources. 418.56 Section 418.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid Subcategory §...

  11. 40 CFR 418.56 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Pretreatment standards for new sources. 418.56 Section 418.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid Subcategory §...

  12. 40 CFR 418.56 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Pretreatment standards for new sources. 418.56 Section 418.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid Subcategory §...

  13. 40 CFR 418.56 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Pretreatment standards for new sources. 418.56 Section 418.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid Subcategory §...

  14. 40 CFR 418.56 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Pretreatment standards for new sources. 418.56 Section 418.56 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Nitric Acid Subcategory §...

  15. Comparison of different pretreatment methods for separation hemicellulose from straw during the lignocellulosic bioethanol production

    NASA Astrophysics Data System (ADS)

    Eisenhuber, Katharina; Krennhuber, Klaus; Steinmüller, Viktoria; Kahr, Heike; Jäger, Alexander

    2013-04-01

    The combustion of fossil fuels is responsible for 73% of carbon dioxide emissions into the atmosphere and consequently contributes to global warming. This fact has enormously increased the interest in the development of methods to reduce greenhouse gases. Therefore, the focus is on the production of biofuels from lignocellulosic agricultural residues. The feedstocks used for 2nd generation bioethanol production are lignocellulosic raw materials like different straw types or energy crops like miscanthus sinensis or arundo donax. Lignocellulose consists of hemicellulose (xylose and arabinose), which is bonded to cellulose (glucose) and lignin. Prior to an enzymatic hydrolysis of the polysaccharides and fermentation of the resulting sugars, the lignocelluloses must be pretreated to make the sugar polymers accessible to enzymes. A variety of pretreatment methods are described in the literature: thermophysical, acid-based and alkaline methods.In this study, we examined and compared the most important pretreatment methods: Steam explosion versus acid and alkaline pretreatment. Specific attention was paid to the mass balance, the recovery of C 5 sugars and consumption of chemicals needed for pretreatment. In lab scale experiments, wheat straw was either directly pretreated by steam explosion or by two different protocols. The straw was either soaked in sulfuric acid or in sodium hydroxide solution at different concentrations. For both methods, wheat straw was pretreated at 100°C for 30 minutes. Afterwards, the remaining straw was separated by vacuum filtration from the liquid fraction.The pretreated straw was neutralized, dried and enzymatically hydrolyzed. Finally, the sugar concentrations (glucose, xylose and arabinose) from filtrate and from hydrolysate were determined by HPLC. The recovery of xylose from hemicellulose was about 50% using the sulfuric acid pretreatment and less than 2% using the sodium hydroxide pretreatment. Increasing concentrations of sulfuric acid

  16. Influence of thermal pretreatment on physical and chemical properties of kitchen waste and the efficiency of anaerobic digestion.

    PubMed

    Jin, Yiying; Li, Yangyang; Li, Jinhui

    2016-09-15

    The effects of thermal pretreatment at moderate temperatures (70, 80 and 90 °C) and high temperatures (120, 140 and 160 °C) over heating durations of 10-120 min on the physical and chemical properties of kitchen waste and on anaerobic digestion were investigated. The results show that thermal pretreatment significantly enhances the solubilisation of organic compounds (chemical oxygen demand, crude proteins, crude fats and volatile fatty acids) and their biodegradability during subsequent anaerobic digestion. High temperature and long heating duration are beneficial for the release and reduction of organic compounds, and the efficiency of subsequent anaerobic digestion is improved markedly under these conditions. Moreover, both the methane production rate and methane yield were observed to increase significantly at moderate treatment temperatures when the anaerobic digestion time was longer than 50 h. PMID:27240205

  17. The anaerobic digestion of biologically and physicochemically pretreated oily wastewater.

    PubMed

    Peng, Liyu; Bao, Meidan; Wang, Qingfeng; Wang, Fangchao; Su, Haijia

    2014-01-01

    To enhance the degradation of oily wastewater and its biogas production, a biological-physicochemical pretreatment was introduced prior to the anaerobic digestion system. The digestion thereafter proceeded more efficiently due to the inoculation by oil degrading bacteria (Bacillus). A 2-stage pre-mixing is more effective than directly mixing. The effects on the methane production were also investigated by pre-treatment with ultrasonic (US) treatment, combined with citric acid (CA) addition. US pre-treatment was found to improve the initial methane production, and CA pre-treatment could maintain this improvement during the whole digestion stage. Pre-mixing Bacillus at 9 wt.% inoculation, combined with US for 10 min and a CA concentration of 500 mg/L provided the optimum conditions. The most effective enhancement of methane yield was 1100.46 ml/g VS, exceeding that of the control by 280%. The change of coenobium shape and fatty acid content further proved that such pretreatment of oily wastewater can facilitate digestion. PMID:24240183

  18. Urine Pretreatment Configuration and Test Results for Space Applications

    NASA Technical Reports Server (NTRS)

    Howard, Stanley G.; Hutchens, Cindy F.; Rethke, Donald W.; Swartley, Vernon L.; Marsh, Robert W.

    1998-01-01

    Pretreatment of urine using Oxone and sulfuric acid is baselined in the International Space Station (ISS) waste water reclamation system to control odors, fix urea and control microbial growth. In addition, pretreatment is recommended for long term flight use of urine collection and two phase separation to reduce or eliminate fouling of the associated hardware and plumbing with urine precipitates. This is important for ISS application because the amount of maintenance time for cleaning and repairing hardware must be minimized. This paper describes the development of a chemical pretreatment system based on solid tablet shapes which are positioned in the urine collection hose and are dissolved by the intrained urine at the proper ratio of pretreatment to urine. Building upon the prior success of the developed and tested solid Oxone tablet a trade study was completed to confirm if a similar approach, or alternative, would be appropriate for the sulfuric acid injection method. In addition, a recommended handling and packaging approach of the solid tablets for long term, safe and convenient use on ISS was addressed. Consequently, the solid tablet concept with suitable packaging was identified as the Urine Pretreat / Prefilter Assembly (UPPA). Testing of the UPPA configuration confirmed the disolution rates and ratios required by ISS were achieved. This testing included laboratory controlled methods as well as a 'real world' test evaluation that occurred during the 150 day Stage 10 Water Recovery Test (WRT) conducted at NASA Marshall Space Flight Center (MSFC).

  19. Pre-Treatment with Allopurinol or Uricase Attenuates Barrier Dysfunction but Not Inflammation during Murine Ventilator-Induced Lung Injury

    PubMed Central

    Kuipers, Maria T.; Aslami, Hamid; Vlaar, Alexander P. J.; Juffermans, Nicole P.; Tuip-de Boer, Anita M.; Hegeman, Maria A.; Jongsma, Geartsje; Roelofs, Joris J. T. H.; van der Poll, Tom; Schultz, Marcus J.; Wieland, Catharina W.

    2012-01-01

    Introduction Uric acid released from injured tissue is considered a major endogenous danger signal and local instillation of uric acid crystals induces acute lung inflammation via activation of the NLRP3 inflammasome. Ventilator-induced lung injury (VILI) is mediated by the NLRP3 inflammasome and increased uric acid levels in lung lavage fluid are reported. We studied levels in human lung injury and the contribution of uric acid in experimental VILI. Methods Uric acid levels in lung lavage fluid of patients with acute lung injury (ALI) were determined. In a different cohort of cardiac surgery patients, uric acid levels were correlated with pulmonary leakage index. In a mouse model of VILI the effect of allopurinol (inhibits uric acid synthesis) and uricase (degrades uric acid) pre-treatment on neutrophil influx, up-regulation of adhesion molecules, pulmonary and systemic cytokine levels, lung pathology, and regulation of receptors involved in the recognition of uric acid was studied. In addition, total protein and immunoglobulin M in lung lavage fluid and pulmonary wet/dry ratios were measured as markers of alveolar barrier dysfunction. Results Uric acid levels increased in ALI patients. In cardiac surgery patients, elevated levels correlated significantly with the pulmonary leakage index. Allopurinol or uricase treatment did not reduce ventilator-induced inflammation, IκB-α degradation, or up-regulation of NLRP3, Toll-like receptor 2, and Toll