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Sample records for alkaline peroxide pretreatment

  1. Ozonation and alkaline-peroxide pretreatment of wheat straw for Cryptococcus curvatus fermentation

    NASA Technical Reports Server (NTRS)

    Greenwalt, C. J.; Hunter, J. B.; Lin, S.; McKenzie, S.; Denvir, A.

    2000-01-01

    Crop residues in an Advanced Life Support System (ALS) contain many valuable components that could be recovered and used. Wheat is 60% inedible, with approximately 90% of the total sugars in the residue cellulose and hemicellulose. To release these sugars requires pretreatment followed by enzymatic hydrolysis. Cryptococcus curvatus, an oleaginous yeast, uses the sugars in cellulose and hemicellulose for growth and production of storage triglycerides. In this investigation, alkaline-peroxide and ozonation pretreatment methods were compared for their efficiency to release glucose and xylose to be used in the cultivation of C. curvatus. Leaching the biomass with water at 65 degrees C for 4 h prior to pretreatment facilitated saccharification. Alkaline-peroxide and ozone pretreatment were almost 100% and 80% saccharification efficient, respectively. The sugars derived from the hydrolysis of alkaline-peroxide-treated wheat straw supported the growth of C. curvatus and the production of edible single-cell oil.

  2. Alkaline peroxide pretreatment of corn stover for enzymatic saccharification and ethanol production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alkaline hydrogen peroxide (AHP) pretreatment and enzymatic saccharification were evaluated for conversion of corn stover cellulose and hemicellulose to fermentable sugars. Corn stover used in this study contained 37.0±0.2% cellulose, 26.8±0.2% hemicellulose and 18.0±0.1% lignin on dry basis. Unde...

  3. A Comparison between Lime and Alkaline Hydrogen Peroxide Pretreatments of Sugarcane Bagasse for Ethanol Production

    NASA Astrophysics Data System (ADS)

    Rabelo, Sarita C.; Filho, Rubens Maciel; Costa, Aline C.

    Pretreatment procedures of sugarcane bagasse with lime (calcium hydroxide) or alkaline hydrogen peroxide were evaluated and compared. Analyses were performed using 2 × 2 × 2 factorial designs, with pretreatment time, temperature, and lime loading and hydrogen peroxide concentration as factors. The responses evaluated were the yield of total reducing sugars (TRS) and glucose released from pretreated bagasse after enzymatic hydrolysis. Experiments were performed using the bagasse as it comes from an alcohol/ sugar factory and bagasse in the size range of 0.248 to 1.397 mm (12-60 mesh). The results show that when hexoses and pentoses are of interest, lime should be the pretreatment agent chosen, as high TRS yields are obtained for nonscreened bagasse using 0.40 g lime/g dry biomass at 70 °C for 36 h. When the product of interest is glucose, the best results were obtained with lime pretreatment of screened bagasse. However, the results for alkaline peroxide and lime pretreatments of nonscreened bagasse are not very different.

  4. Alkaline hydrogen peroxide pretreatment of cashew apple bagasse for ethanol production: study of parameters.

    PubMed

    Correia, Jessyca Aline da Costa; Júnior, José Edvan Marques; Gonçalves, Luciana Rocha B; Rocha, Maria Valderez Ponte

    2013-07-01

    The alkaline hydrogen peroxide (AHP) pretreatment of cashew apple bagasse (CAB) was evaluated based on the conversion of the resultant cellulose into glucose. The effects of the concentration of hydrogen peroxide at pH 11.5, the biomass loading and the pretreatment duration performed at 35°C and 250 rpm were evaluated after the subsequent enzymatic saccharification of the pretreated biomass using a commercial cellulase enzyme. The CAB used in this study contained 20.56 ± 2.19% cellulose, 10.17 ± 0.89% hemicellulose and 35.26 ± 0.90% lignin. The pretreatment resulted in a reduced lignin content in the residual solids. Increasing the H2O2 concentration (0-4.3% v/v) resulted in a higher rate of enzymatic hydrolysis. Lower biomass loadings gave higher glucose yields. In addition, no measurable furfural and hydroxymethyl furfural were produced in the liquid fraction during the pretreatment. The results show that alkaline hydrogen peroxide is effective for the pretreatment of CAB.

  5. Fuel ethanol production from alkaline peroxide pretreated corn stover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn stover (CS) has the potential to serve as an abundant low-cost feedstock for production of fuel ethanol. Due to heterogeneous complexity and recalcitrance of lignocellulosic feedstocks, pretreatment is required to break the lignin seal and/or disrupt the structure of crystalline cellulose to in...

  6. Catalysis with Cu(II) (bpy) improves alkaline hydrogen peroxide pretreatment.

    PubMed

    Li, Zhenglun; Chen, Charles H; Liu, Tongjun; Mathrubootham, Vaidyanathan; Hegg, Eric L; Hodge, David B

    2013-04-01

    Copper(II) 2,2'-bipyridine (Cu(II) (bpy))-catalyzed alkaline hydrogen peroxide (AHP) pretreatment was performed on three biomass feedstocks including alkali pre-extracted switchgrass, silver birch, and a hybrid poplar cultivar. This catalytic approach was found to improve the subsequent enzymatic hydrolysis of plant cell wall polysaccharides to monosaccharides for all biomass types at alkaline pH relative to uncatalyzed pretreatment. The hybrid poplar exhibited the most significant improvement in enzymatic hydrolysis with monomeric sugar release and conversions more than doubling from 30% to 61% glucan conversion, while lignin solubilization was increased from 36.6% to 50.2% and hemicellulose solubilization was increased from 14.9% to 32.7%. It was found that Cu(II) (bpy)-catalyzed AHP pretreatment of cellulose resulted in significantly more depolymerization than uncatalyzed AHP pretreatment (78.4% vs. 49.4% decrease in estimated degree of polymerization) and that carboxyl content the cellulose was significantly increased as well (fivefold increase vs. twofold increase). Together, these results indicate that Cu(II) (bpy)-catalyzed AHP pretreatment represents a promising route to biomass deconstruction for bioenergy applications.

  7. Alkaline peroxide assisted wet air oxidation pretreatment approach to enhance enzymatic convertibility of rice husk.

    PubMed

    Banerjee, Saumita; Sen, Ramkrishna; Mudliar, Sandeep; Pandey, R A; Chakrabarti, Tapan; Satpute, Dewanand

    2011-01-01

    Pretreatment of rice husk by alkaline peroxide assisted wet air oxidation (APAWAO) approach was investigated with the aim to enhance the enzymatic convertibility of cellulose in pretreated rice husk. Rice husk was presoaked overnight in 1% (w/v) H(2)O(2) solution (pH adjusted to 11.5 using NaOH) (equivalent to 16.67 g H(2)O(2) and 3.63 g NaOH per 100 g dry, untreated rice husk) at room temperature, followed by wet air oxidation (WAO). APAWAO pretreatment resulted in solubilization of 67 wt % of hemicellulose and 88 wt % of lignin initially present in raw rice husk. Some amount of oligomeric glucose (˜8.3 g/L) was also observed in the APAWAO liquid fraction. APAWAO pretreatment resulted in 13-fold increase in the amount of glucose that could be obtained from otherwise untreated rice husk. Up to 86 wt % of cellulose in the pretreated rice husk (solid fraction) could be converted into glucose within 24 hours, yielding over 21 g glucose per 100 g original rice husk. Scanning electron microscopy was performed to visualize changes in biomass structure following the APAWAO pretreatment. Enzymatic cellulose convertibility of the pretreated slurry at high dry matter loadings was also investigated.

  8. Structural characterization of alkaline hydrogen peroxide pretreated grasses exhibiting diverse lignin phenotypes

    PubMed Central

    2012-01-01

    Background For cellulosic biofuels processes, suitable characterization of the lignin remaining within the cell wall and correlation of quantified properties of lignin to cell wall polysaccharide enzymatic deconstruction is underrepresented in the literature. This is particularly true for grasses which represent a number of promising bioenergy feedstocks where quantification of grass lignins is particularly problematic due to the high fraction of p-hydroxycinnamates. The main focus of this work is to use grasses with a diverse range of lignin properties, and applying multiple lignin characterization platforms, attempt to correlate the differences in these lignin properties to the susceptibility to alkaline hydrogen peroxide (AHP) pretreatment and subsequent enzymatic deconstruction. Results We were able to determine that the enzymatic hydrolysis of cellulose to to glucose (i.e. digestibility) of four grasses with relatively diverse lignin phenotypes could be correlated to total lignin content and the content of p-hydroxycinnamates, while S/G ratios did not appear to contribute to the enzymatic digestibility or delignification. The lignins of the brown midrib corn stovers tested were significantly more condensed than a typical commercial corn stover and a significant finding was that pretreatment with alkaline hydrogen peroxide increases the fraction of lignins involved in condensed linkages from 88–95% to ~99% for all the corn stovers tested, which is much more than has been reported in the literature for other pretreatments. This indicates significant scission of β-O-4 bonds by pretreatment and/or induction of lignin condensation reactions. The S/G ratios in grasses determined by analytical pyrolysis are significantly lower than values obtained using either thioacidolysis or 2DHSQC NMR due to presumed interference by ferulates. Conclusions It was found that grass cell wall polysaccharide hydrolysis by cellulolytic enzymes for grasses exhibiting a diversity of

  9. Enhanced enzymatic hydrolysis and ethanol production from cashew apple bagasse pretreated with alkaline hydrogen peroxide.

    PubMed

    da Costa, Jessyca Aline; Marques, José Edvan; Gonçalves, Luciana Rocha Barros; Rocha, Maria Valderez Ponte

    2015-03-01

    The effect of combinations and ratios between different enzymes has been investigated in order to assess the optimal conditions for hydrolysis of cashew apple bagasse pretreated with alkaline hydrogen peroxide (the solids named CAB-AHP). The separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes were evaluated in the ethanol production. The enzymatic hydrolysis conducted with cellulase complex and β-glucosidase in a ratio of 0.61:0.39, enzyme loading of 30FPU/g(CAB-AHP) and 66CBU/g(CAB-AHP), respectively, using 4% cellulose from CAB-AHP, turned out to be the most effective conditions, with glucose and xylose yields of 511.68 mg/g(CAB-AHP) and 237.8 mg/g(CAB-AHP), respectively. Fermentation of the pure hydrolysate by Kluyveromyces marxianus ATCC 36907 led to an ethanol yield of 61.8kg/ton(CAB), corresponding to 15 g/L ethanol and productivity of 3.75 g/( Lh). The ethanol production obtained for SSF process using K. marxianus ATCC 36907 was 18 g/L corresponding to 80% yield and 74.2kg/ton(CAB).

  10. [Effect of Residual Hydrogen Peroxide on Hydrolysis Acidification of Sludge Pretreated by Microwave -H2O2-Alkaline Process].

    PubMed

    Jia, Rui-lai; Liu, Ji-bao; Wei, Yuan-song; Cai, Xing

    2015-10-01

    Previous studies have found that in the hydrolysis acidification process, sludge after microwave -H2O2-alkaline (MW-H2O2-OH, pH = 10) pretreatment had an acid production lag due to the residual hydrogen peroxide. In this study, effects of residual hydrogen peroxide after MW-H2O2-OH (pH = 10 or pH = 11) pretreatment on the sludge hydrolysis acidification were investigated through batch experiments. Our results showed that catalase had a higher catalytic efficiency than manganese dioxide for hydrogen peroxide, which could completely degraded hydrogen peroxide within 10 min. During the 8 d of hydrolysis acidification time, both SCOD concentrations and the total VFAs concentrations of four groups were firstly increased and then decreased. The optimized hydrolysis times were 0.5 d for four groups, and the optimized hydrolysis acidification times were 3 d for MW-H2O2-OH (pH = 10) group, MW-H2O2-OH (pH = 10) + catalase group and MW-H2O2-OH (pH = 11) + catalase group. The optimized hydrolysis acidification time for MW-H2O2-OH (pH = 11) group was 4 d. Residual hydrogen peroxide inhibited acid production for sludge after MW-H2O2-OH (pH = 10) pretreatment, resulting in a lag in acidification stage. Compared with MW-H2O2-OH ( pH = 10) pretreatment, MW-H2O2-OH (pH = 11 ) pretreatment released more SCOD by 19.29% and more organic matters, which resulted in the increase of total VFAs production significantly by 84.80% at 5 d of hydrolysis acidification time and MW-H2O2-OH (pH = 11) group could shorten the lag time slightly. Dosing catalase (100 mg x -L(-1)) after the MW-H2O2-OH (pH = 10 or pH = 11) pretreatment not only significantly shortened the lag time (0.5 d) in acidification stage, but also produced more total VFAs by 23.61% and 50.12% in the MW-H2O2-OH (pH = 10) + catalase group and MW-H2O2-OH (pH = 11) + catalase group, compared with MW-H2O2-OH (pH = 10) group at 3d of hydrolysis acidification time. For MW-H2O2-OH (pH = 10) group, MW-H2O2-OH (pH = 10) + catalase group and

  11. Harnessing Genetic Diversity in Saccharomyces cerevisiae for Fermentation of Xylose in Hydrolysates of Alkaline Hydrogen Peroxide-Pretreated Biomass

    PubMed Central

    Liu, Tongjun; Parreiras, Lucas S.; Williams, Daniel L.; Wohlbach, Dana J.; Bice, Benjamin D.; Ong, Irene M.; Breuer, Rebecca J.; Qin, Li; Busalacchi, Donald; Deshpande, Shweta; Daum, Chris; Gasch, Audrey P.

    2014-01-01

    The fermentation of lignocellulose-derived sugars, particularly xylose, into ethanol by the yeast Saccharomyces cerevisiae is known to be inhibited by compounds produced during feedstock pretreatment. We devised a strategy that combined chemical profiling of pretreated feedstocks, high-throughput phenotyping of genetically diverse S. cerevisiae strains isolated from a range of ecological niches, and directed engineering and evolution against identified inhibitors to produce strains with improved fermentation properties. We identified and quantified for the first time the major inhibitory compounds in alkaline hydrogen peroxide (AHP)-pretreated lignocellulosic hydrolysates, including Na+, acetate, and p-coumaric (pCA) and ferulic (FA) acids. By phenotyping these yeast strains for their abilities to grow in the presence of these AHP inhibitors, one heterozygous diploid strain tolerant to all four inhibitors was selected, engineered for xylose metabolism, and then allowed to evolve on xylose with increasing amounts of pCA and FA. After only 149 generations, one evolved isolate, GLBRCY87, exhibited faster xylose uptake rates in both laboratory media and AHP switchgrass hydrolysate than its ancestral GLBRCY73 strain and completely converted 115 g/liter of total sugars in undetoxified AHP hydrolysate into more than 40 g/liter ethanol. Strikingly, genome sequencing revealed that during the evolution from GLBRCY73, the GLBRCY87 strain acquired the conversion of heterozygous to homozygous alleles in chromosome VII and amplification of chromosome XIV. Our approach highlights that simultaneous selection on xylose and pCA or FA with a wild S. cerevisiae strain containing inherent tolerance to AHP pretreatment inhibitors has potential for rapid evolution of robust properties in lignocellulosic biofuel production. PMID:24212571

  12. Harnessing genetic diversity in Saccharomyces cerevisiae for fermentation of xylose in hydrolysates of alkaline hydrogen peroxide-pretreated biomass.

    PubMed

    Sato, Trey K; Liu, Tongjun; Parreiras, Lucas S; Williams, Daniel L; Wohlbach, Dana J; Bice, Benjamin D; Ong, Irene M; Breuer, Rebecca J; Qin, Li; Busalacchi, Donald; Deshpande, Shweta; Daum, Chris; Gasch, Audrey P; Hodge, David B

    2014-01-01

    The fermentation of lignocellulose-derived sugars, particularly xylose, into ethanol by the yeast Saccharomyces cerevisiae is known to be inhibited by compounds produced during feedstock pretreatment. We devised a strategy that combined chemical profiling of pretreated feedstocks, high-throughput phenotyping of genetically diverse S. cerevisiae strains isolated from a range of ecological niches, and directed engineering and evolution against identified inhibitors to produce strains with improved fermentation properties. We identified and quantified for the first time the major inhibitory compounds in alkaline hydrogen peroxide (AHP)-pretreated lignocellulosic hydrolysates, including Na(+), acetate, and p-coumaric (pCA) and ferulic (FA) acids. By phenotyping these yeast strains for their abilities to grow in the presence of these AHP inhibitors, one heterozygous diploid strain tolerant to all four inhibitors was selected, engineered for xylose metabolism, and then allowed to evolve on xylose with increasing amounts of pCA and FA. After only 149 generations, one evolved isolate, GLBRCY87, exhibited faster xylose uptake rates in both laboratory media and AHP switchgrass hydrolysate than its ancestral GLBRCY73 strain and completely converted 115 g/liter of total sugars in undetoxified AHP hydrolysate into more than 40 g/liter ethanol. Strikingly, genome sequencing revealed that during the evolution from GLBRCY73, the GLBRCY87 strain acquired the conversion of heterozygous to homozygous alleles in chromosome VII and amplification of chromosome XIV. Our approach highlights that simultaneous selection on xylose and pCA or FA with a wild S. cerevisiae strain containing inherent tolerance to AHP pretreatment inhibitors has potential for rapid evolution of robust properties in lignocellulosic biofuel production.

  13. Formulation of enzyme blends to maximize the hydrolysis of alkaline peroxide pretreated alfalfa hay and barley straw by rumen enzymes and commercial cellulases

    PubMed Central

    2014-01-01

    Background Efficient conversion of lignocellulosic biomass to fermentable sugars requires the synergistic action of multiple enzymes; consequently enzyme mixtures must be properly formulated for effective hydrolysis. The nature of an optimal enzyme blends depends on the type of pretreatment employed as well the characteristics of the substrate. In this study, statistical experimental design was used to develop mixtures of recombinant glycosyl hydrolases from thermophilic and anaerobic fungi that enhanced the digestion of alkaline peroxide treated alfalfa hay and barley straw by mixed rumen enzymes as well as commercial cellulases (Accelerase 1500, A1500; Accelerase XC, AXC). Results Combinations of feruloyl and acetyl xylan esterases (FAE1a; AXE16A_ASPNG), endoglucanase GH7 (EGL7A_THITE) and polygalacturonase (PGA28A_ASPNG) with rumen enzymes improved straw digestion. Inclusion of pectinase (PGA28A_ASPNG), endoxylanase (XYN11A_THITE), feruloyl esterase (FAE1a) and β-glucosidase (E-BGLUC) with A1500 or endoglucanase GH7 (EGL7A_THITE) and β-xylosidase (E-BXSRB) with AXC increased glucose release from alfalfa hay. Glucose yield from straw was improved when FAE1a and endoglucanase GH7 (EGL7A_THITE) were added to A1500, while FAE1a and AXE16A_ASPNG enhanced the activity of AXC on straw. Xylose release from alfalfa hay was augmented by supplementing A1500 with E-BGLUC, or AXC with EGL7A_THITE and XYN11A_THITE. Adding arabinofuranosidase (ABF54B_ASPNG) and esterases (AXE16A_ASPNG; AXE16B_ASPNG) to A1500, or FAE1a and AXE16A_ASPNG to AXC enhanced xylose release from barley straw, a response confirmed in a scaled up assay. Conclusion The efficacy of commercial enzyme mixtures as well as mixed enzymes from the rumen was improved through formulation with synergetic recombinant enzymes. This approach reliably identified supplemental enzymes that enhanced sugar release from alkaline pretreated alfalfa hay and barley straw. PMID:24766728

  14. Alkaline peroxide mechanical pulping of wheat straw with enzyme treatment.

    PubMed

    Zhao, Jian; Li, Xuezhi; Qu, Yinbo; Gao, Peiji

    2004-01-01

    Alkaline peroxide mechanical pulping (APMP) of wheat straw with enzyme treatment was studied. Instead of direct enzyme pretreatment on wheat straw, an alternative treatment method was used, in which coarse pulps from refiner defibrated wheat straw rather than wheat straw were pretreated with a crude enzyme containing mainly xylanase, then impregnated with alkaline H2O2 solution and further refined. The optimum conditions of enzyme treatment were xylanase dosage of 10-15 IU/g of oven-dried wheat straw, 90 min, 50-60 degrees C, pulp consistency of 5-10%, and initial pH of 5.0, and those for chemical impregnation were 6% NaOH, 70-80 degrees C, 60-90 min, and 4 to 5% H2O2. Enzyme treatment improved pulpability of wheat straw by the APMP process, and final pulp quality such as brightness, breaking length, and burst index of pulp. Pulp from the APMP process with enzyme treatment could be bleached to a brightness of 70.5% ISO by two-stage H2O2 bleaching sequence with only 4% H2O2, and breaking length of the bleach pulp reached 4470 m

  15. Titrimetric determination of hydrogen peroxide in alkaline solution.

    PubMed

    McCurdy, W H; Bell, H F

    1966-07-01

    Direct titration of hydrogen peroxide in alkaline bromide media has been accomplished with sodium hypochlorite. The relative standard deviation is 0.2%. A photometric end-point is recommended for the determination of 0.10-1.0 mequiv of peroxide. Larger samples are evaluated by use of Bordeaux Red as visual indicator. The hypochlorite procedure compares favourably with iodometry and permanganate in the analysis of commercial peroxides.

  16. Alkaline peroxide delignification of agricultural residues to enhance enzymatic saccharification. [Trichoderma reesei

    SciTech Connect

    Gould, J.M.

    1984-01-01

    Approximately one-half of the lignin and most of the hemicellulose present in agricultural residues such as wheat straw and corn stover are solubilized when the residue is treated at 25/sup 0/C in an alkaline solution of hydrogen peroxide. The delignification reaction is most efficient when the ratio of hydrogen peroxide to substrate is at least 0.25 (w/w) and the pH is 11.5. The supernatant fraction from a given pretreatment, after addition of makeup peroxide and readjustment of the pH, can be recycled to treat at least six additional batches of substrate, resulting in a substantial concentration of hemicellulose and soluble lignin degradation products. Hydrolysis of the insoluble fraction with Trichoderma reesei cellulase after alkline peroxide treatment yields glucose with almost 100% efficiency, based upon the cellulose content of the residue before treatment. These data indicate that alkaline peroxide pretreatment is a simple and efficient method for enhancing the enzymatic digestibility of lignocellulosic crop residues to levels approaching the theoretical maximum.

  17. 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.

  18. 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

  19. Techno-economic comparison of centralized versus decentralized biorefineries for two alkaline pretreatment processes.

    PubMed

    Stoklosa, Ryan J; Del Pilar Orjuela, Andrea; da Costa Sousa, Leonardo; Uppugundla, Nirmal; Williams, Daniel L; Dale, Bruce E; Hodge, David B; Balan, Venkatesh

    2017-02-01

    In this work, corn stover subjected to ammonia fiber expansion (AFEX™)(1) pretreatment or alkaline pre-extraction followed by hydrogen peroxide post-treatment (AHP pretreatment) were compared for their enzymatic hydrolysis yields over a range of solids loadings, enzymes loadings, and enzyme combinations. Process techno-economic models were compared for cellulosic ethanol production for a biorefinery that handles 2000tons per day of corn stover employing a centralized biorefinery approach with AHP or a de-centralized AFEX pretreatment followed by biomass densification feeding a centralized biorefinery. A techno-economic analysis (TEA) of these scenarios shows that the AFEX process resulted in the highest capital investment but also has the lowest minimum ethanol selling price (MESP) at $2.09/gal, primarily due to good energy integration and an efficient ammonia recovery system. The economics of AHP could be made more competitive if oxidant loadings were reduced and the alkali and sugar losses were also decreased.

  20. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    PubMed

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.

  1. Alkaline twin-screw extrusion pretreatment for fermentable sugar production

    PubMed Central

    2013-01-01

    Background The inevitable depletion of fossil fuels has resulted in an increasing worldwide interest in exploring alternative and sustainable energy sources. Lignocellulose, which is the most abundant biomass on earth, is widely regarded as a promising raw material to produce fuel ethanol. Pretreatment is an essential step to disrupt the recalcitrance of lignocellulosic matrix for enzymatic saccharification and bioethanol production. This paper established an ATSE (alkaline twin-screw extrusion pretreatment) process using a specially designed twin-screw extruder in the presence of alkaline solution to improve the enzymatic hydrolysis efficiency of corn stover for the production of fermentable sugars. Results The ATSE pretreatment was conducted with a biomass/liquid ratio of 1/2 (w/w) at a temperature of 99°C without heating equipment. The results indicated that ATSE pretreatment is effective in improving the enzymatic digestibility of corn stover. Sodium hydroxide loading is more influential factor affecting both sugar yield and lignin degradation than heat preservation time. After ATSE pretreatment under the proper conditions (NaOH loading of 0.06 g/g biomass during ATSE and 1 hour heat preservation after extrusion), 71% lignin removal was achieved and the conversions of glucan and xylan in the pretreated biomass can reach to 83% and 89% respectively via subsequent enzymatic hydrolysis (cellulase loading of 20 FPU/g-biomass and substrate consistency of 2%). About 78% of the original polysaccharides were converted into fermentable sugars. Conclusions With the physicochemical functions in extrusion, the ATSE method can effectively overcome the recalcitrance of lignocellulose for the production of fermentable sugars from corn stover. This process can be considered as a promising pretreatment method due to its relatively low temperature (99°C), high biomass/liquid ratio (1/2) and satisfied total sugar yield (78%), despite further study is needed for process

  2. Pilot-Scale Batch Alkaline Pretreatment of Corn Stover

    SciTech Connect

    Kuhn, Erik M.; O’Brien, Marykate H.; Ciesielski, Peter N.; Schell, Daniel J.

    2015-12-18

    The goal of biomass pretreatment is to increase the enzymatic digestibility of the plant cell wall polysaccharides to produce sugars for upgrading to biofuels. Alkaline pretreatment has the ability to solubilize much of the lignin in biomass while the carbohydrates remain insoluble. With an increased research focus to produce high-value products from lignin, a low molecular weight, lignin-rich stream in a biorefinery is desirable. Here, this work reports on batch alkaline pretreatment of corn stover conducted using a three-factor, two-level central composite experimental design in a pilot-scale reactor to determine the relationship between sodium hydroxide (NaOH) loading, temperature, and anthraquinone (AQ) charge on solids solubilization, component yields, and enzymatic digestibility of the residual solids. Operating conditions were 100 to 140 °C, 40 to 70 mg NaOH/g dry corn stover, and 0.05% to 0.2% (w/w) AQ loading. An enzymatic hydrolysis screening study was performed at 2% cellulose loading. Empirical modeling results showed that NaOH loading and temperature are both significant factors, solubilizing 15% to 35% of the solids and up to 54% of the lignin. Enzymatic hydrolysis of the residual solids produced good monomeric glucose (>90%) and xylose (>70%) yields at the more severe pretreatment conditions. We also found that the AQ charge was not a significant factor at the conditions studied, so efforts to reduce xylan and increase lignin solubilization using this compound were not successful. Lastly, while good lignin solubilization was achieved, effectively recovering this stream remains a challenge, and demonstrating performance in continuous reactors is still needed.

  3. Pilot-Scale Batch Alkaline Pretreatment of Corn Stover

    DOE PAGES

    Kuhn, Erik M.; O’Brien, Marykate H.; Ciesielski, Peter N.; ...

    2015-12-18

    The goal of biomass pretreatment is to increase the enzymatic digestibility of the plant cell wall polysaccharides to produce sugars for upgrading to biofuels. Alkaline pretreatment has the ability to solubilize much of the lignin in biomass while the carbohydrates remain insoluble. With an increased research focus to produce high-value products from lignin, a low molecular weight, lignin-rich stream in a biorefinery is desirable. Here, this work reports on batch alkaline pretreatment of corn stover conducted using a three-factor, two-level central composite experimental design in a pilot-scale reactor to determine the relationship between sodium hydroxide (NaOH) loading, temperature, and anthraquinonemore » (AQ) charge on solids solubilization, component yields, and enzymatic digestibility of the residual solids. Operating conditions were 100 to 140 °C, 40 to 70 mg NaOH/g dry corn stover, and 0.05% to 0.2% (w/w) AQ loading. An enzymatic hydrolysis screening study was performed at 2% cellulose loading. Empirical modeling results showed that NaOH loading and temperature are both significant factors, solubilizing 15% to 35% of the solids and up to 54% of the lignin. Enzymatic hydrolysis of the residual solids produced good monomeric glucose (>90%) and xylose (>70%) yields at the more severe pretreatment conditions. We also found that the AQ charge was not a significant factor at the conditions studied, so efforts to reduce xylan and increase lignin solubilization using this compound were not successful. Lastly, while good lignin solubilization was achieved, effectively recovering this stream remains a challenge, and demonstrating performance in continuous reactors is still needed.« less

  4. Alkaline pretreatment for chlorine removal from high-chlorine rhodochrosite

    NASA Astrophysics Data System (ADS)

    Zhang, Xing-ran; Liu, Zuo-hua; Li, Wen-sheng; Cheng, Ya-ya; Du, Jun; Tao, Chang-yuan

    2016-11-01

    Chloride in manganese ore adversely affects mineral extraction. The mechanisms and the factors that influence an alkali pretreatment to removal chlorine from manganese ore were explored to eliminate hazards posed by chlorine during the electrolysis of manganese. The results showed that sodium carbonate, when used as an alkaline additive, promoted the dissolution of insoluble chloride, enhanced the migration of chloride ions, and effectively stabilized Mn2+. The optimal conditions were a sodium carbonate concentration of 0.45 mol·L-1, a liquid-solid ratio of 5:1 mL·g-1, a reaction time of 1 h, and a temperature of 25°C. The chlorine removal efficiency was greater than 95%, and the ore grade (Mn) was increased by 2.7%.

  5. Improving methane production from digested manure biofibers by mechanical and thermal alkaline pretreatment.

    PubMed

    Tsapekos, P; Kougias, Panagiotis G; Frison, A; Raga, R; Angelidaki, I

    2016-09-01

    Animal manure digestion is associated with limited methane production, due to the high content in fibers, which are hardly degradable lignocellulosic compounds. In this study, different mechanical and thermal alkaline pretreatment methods were applied to partially degradable fibers, separated from the effluent stream of biogas reactors. Batch and continuous experiments were conducted to evaluate the efficiency of these pretreatments. In batch experiments, the mechanical pretreatment improved the degradability up to 45%. Even higher efficiency was shown by applying thermal alkaline pretreatments, enhancing fibers degradability by more than 4-fold. In continuous experiments, the thermal alkaline pretreatment, using 6% NaOH at 55°C was proven to be the most efficient pretreatment method as the methane production was increased by 26%. The findings demonstrated that the methane production of the biogas plants can be increased by further exploiting the fraction of the digested manure fibers which are discarded in the post-storage tank.

  6. Exploring crystalline-structural variations of cellulose during alkaline pretreatment for enhanced enzymatic hydrolysis.

    PubMed

    Ling, Zhe; Chen, Sheng; Zhang, Xun; Xu, Feng

    2017-01-01

    The study aimed to explore the crystallinity and crystalline structure of alkaline pretreated cellulose. The enzymatic hydrolysis followed by pretreatment was conducted for measuring the efficiency of sugar conversion. For cellulose Iβ dominated samples, alkaline pretreatment (<8wt%) caused increased cellulose crystallinity and depolymerized hemicelluloses, that were superimposed to affect the enzymatic conversion to glucose. Varying crystallite sizes and lattice spacings indicated the separation of cellulose crystals during mercerization (8-12wt% NaOH). Completion of mercerization was proved under higher alkaline concentration (14-18wt% NaOH), leading to distortion of crystalline cellulose to some extent. Cellulose II crystallinity showed a stimulative impact on enzymatic hydrolysis due to the weakened hydrophobic interactions within cellulose chains. The current study may provide innovative explanations for enhanced enzymatic digestibility of alkaline pretreated lignocellulosic materials.

  7. Low-heat, mild alkaline pretreatment of switchgrass for anaerobic digestion.

    PubMed

    Jin, Guang; Bierma, Tom; Walker, Paul M

    2014-01-01

    This study examines the effectiveness of alkaline pretreatment under mild heat conditions (100°C or 212°F) on the anaerobic co-digestion of switchgrass. The effects of alkaline concentration, types of alkaline, heating time and rinsing were evaluated. In addition to batch studies, continuous-feed studies were performed in triplicate to identify potential digester operational problems caused by switchgrass co-digestion while accounting for uncertainty due to digester variability. Few studies have examined anaerobic digestion of switchgrass or the effects of mild heating to enhance alkaline pretreatment prior to biomass digestion. Results indicate that pretreatment can significantly enhance digestion of coarse-ground (≤ 0.78 cm particle size) switchgrass. Energy conversion efficiency as high as 63% was observed, and was comparable or superior to fine-grinding as a pretreatment method. The optimal NaOH concentration was found to be 5.5% (wt/wt alkaline/biomass) with a 91.7% moisture level. No evidence of operational problems such as solids build-up, poor mixing, or floating materials were observed. These results suggest the use of waste heat from a generator could reduce the concentration of alkaline required to adequately pretreat lignocellulosic feedstock prior to anaerobic digestion.

  8. The corrosion of titanium in alkaline peroxide bleach liquors

    SciTech Connect

    Wyllie, W.E. II; Brown, B.E.; Duquette, D.J.

    1994-12-31

    An experimental program to determine the effects of hydrogen peroxide (H{sub 2}O{sub 2}) and of potential corrosion inhibitors on the corrosion behavior of titanium has been developed. Corrosion rates less than 0.25 mm/y were observed in laboratory bleach liquor at pH 12 to which 5 g/l of H{sub 2}O{sub 2} were added. At pH 13, with 10 g/l H{sub 2}O{sub 2}, the corrosion rates were unacceptably high in both sodium hydroxide (NaOH) and laboratory bleach liquor solutions (>8.38 mm/y). The preliminary results of inhibitor studies indicated that the addition of 3.7 g/l sodium silicate or 0.01 g/l calcium nitrate (Ca(NO{sub 3}){sub 2}) effectively inhibited the corrosion of titanium exposed to 5 g/l of H{sub 2}O{sub 2} in NaOH solutions of pH 12. It was also found that in simulated paper mill chemistries, i.e., basic solutions containing 3.7 g/l sodium silicate and 0.6 g/l EDTA (ethylenediaminetetraacetic acid), corrosion rates increased markedly with the addition of 5 g/l H{sub 2}O{sub 2}. However, subsequent additions of peroxide resulted in corrosion rates which were even lower than those found in NaOH. This is believed to be due to the formation of a black scale on the surface of the sample. The addition of magnesium sulfate (MgSO{sub 4}) in the 0.1--0.5 g/l range also was shown to inhibit corrosion in the NaOH solution, but only after prior exposure to H{sub 2}O{sub 2}.

  9. Acetone-butanol-ethanol production from corn stover pretreated by alkaline twin-screw extrusion pretreatment.

    PubMed

    Zhang, Yuedong; Hou, Tongang; Li, Bin; Liu, Chao; Mu, Xindong; Wang, Haisong

    2014-05-01

    In this study, the alkaline twin-screw extrusion pretreated corn stover was subjected to enzymatic hydrolysis after washing. The impact of solid loading and enzyme dose on enzymatic hydrolysis was investigated. It was found that 68.2 g/L of total fermentable sugar could be obtained after enzymatic hydrolysis with the solid loading of 10 %, while the highest sugar recovery of 91.07 % was achieved when the solid loading was 2 % with the cellulase dose of 24 FPU/g substrate. Subsequently, the hydrolyzate was fermented by Clostridium acetobutylicum ATCC 824. The acetone-butanol-ethanol (ABE) production of the hydrolyzate was compared with the glucose, xylose and simulated hydrolyzate medium which have the same reducing sugar concentration. It was shown that 7.1 g/L butanol and 11.2 g/L ABE could be produced after 72 h fermentation for the hydrolyzate obtained from enzymatic hydrolysis with 6 % solid loading. This is comparable to the glucose and simulated hydrozate medium, and the overall ABE yield could reach 0.112 g/g raw corn stover.

  10. Effect of alkaline pretreatment on anaerobic digestion of solid wastes

    SciTech Connect

    Lopez Torres, M. Espinosa Llorens, Ma. del C.

    2008-11-15

    The introduction of the anaerobic digestion for the treatment of the organic fraction of municipal solid waste (OFMSW) is currently of special interest. The main difficulty in the treatment of this waste fraction is its biotransformation, due to the complexity of organic material. Therefore, the first step must be its physical, chemical and biological pretreatment for breaking complex molecules into simple monomers, to increase solubilization of organic material and improve the efficiency of the anaerobic treatment in the second step. This paper describes chemical pretreatment based on lime addition (Ca(OH){sub 2}), in order to enhance chemical oxygen demand (COD) solubilization, followed by anaerobic digestion of the OFMSW. Laboratory-scale experiments were carried out in completely mixed reactors, 1 L capacity. Optimal conditions for COD solubilization in the first step of pretreatment were 62.0 mEq Ca(OH){sub 2}/L for 6.0 h. Under these conditions, 11.5% of the COD was solubilized. The anaerobic digestion efficiency of the OFMSW, with and without pretreatment, was evaluated. The highest methane yield under anaerobic digestion of the pretreated waste was 0.15 m{sup 3} CH{sub 4}/kg volatile solids (VS), 172.0% of the control. Under that condition the soluble COD and VS removal were 93.0% and 94.0%, respectively. The results have shown that chemical pretreatment with lime, followed by anaerobic digestion, provides the best results for stabilizing the OFMSW.

  11. Progress in alkaline peroxide dissolution of low-enriched uranium metal and silicide targets

    SciTech Connect

    Chen, L.; Dong, D.; Buchholz, B.A.; Vandegrift, G.F.; Wu, D.

    1996-12-31

    This paper reports recent progress on two alkaline peroxide dissolution processes: the dissolution of low-enriched uranium metal and silicide (U{sub 3}Si{sub 2}) targets. These processes are being developed to substitute low-enriched for high-enriched uranium in targets used for production of fission-product {sup 99}Mo. Issues that are addressed include (1) dissolution kinetics of silicide targets, (2) {sup 99}Mo lost during aluminum dissolution, (3) modeling of hydrogen peroxide consumption, (4) optimization of the uranium foil dissolution process, and (5) selection of uranium foil barrier materials. Future work associated with these two processes is also briefly discussed.

  12. Effect of thermal and alkaline pretreatment of giant miscanthus and Chinese fountaingrass on biogas production.

    PubMed

    Nkemka, Valentine Nkongndem; Li, Yongqiang; Hao, Xiying

    2016-01-01

    Giant miscanthus (Miscanthus × giganteus) and Chinese fountaingrass (Pennisetum alopecuroides (L.) Spreng), cultivated for landscaping and soil conservation, are potential energy crops. The study investigated the effect of combined thermal and alkaline pretreatments on biogas production of these energy crops. The pretreatment included two types of alkali (6% CaO and 6% NaOH) at 22, 70 and 100 °C. The alkaline pretreatment resulted in a greater breakdown of the hemicellulose fraction, with CaO more effective than NaOH. Pretreatment of giant miscanthus with 6% CaO at 100 °C for 24 h produced a CH4 yield (313 mL g(-1) volatile solids (VS)) that was 1.7 times that of the untreated sample (186 mL g(-1) VS). However, pretreatment of Chinese fountaingrass with 6% CaO or 6% NaOH at 70 °C for 24 h resulted in similar CH4 yields (328 and 302 mL g(-1) VS for CaO and NaOH pretreatments) as the untreated sample (311 mL g(-1) VS). Chinese fountaingrass was more easily digestible but had a low overall CH4 yield per hectare (1,831 m(3) ha(-1) y(-1)) compared to giant miscanthus (6,868 m(3) ha(-1) y(-1)). This study demonstrates the potential of thermal/alkaline pretreatment and the use of giant miscanthus and Chinese fountaingrass for biogas production.

  13. Synergistic benefits of ionic liquid and alkaline pretreatments of poplar wood. Part 1: effect of integrated pretreatment on enzymatic hydrolysis.

    PubMed

    Yuan, Tong-Qi; Wang, Wei; Xu, Feng; Sun, Run-Cang

    2013-09-01

    An environmentally friendly pretreatment process was developed to fractionate hemicelluloses and lignin from poplar wood by ionic liquid (IL) pretreatment coupled with mild alkaline extraction. Hemicellulosic and lignin fractions were obtained in high yields, amounting to 59.3% and 74.4%, respectively, which can served as raw materials for production of value-added products. The yield of glucose for the integrated pretreated poplar wood was 99.2%, while it was just 19.2% for the untreated material. The synergistic benefits of the removal of lignin and hemicelluloses, the increase of the cellulose surface area, and the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase resulted in the high glucose yield for the integrated pretreated substrate. Therefore, the IL based biorefining strategy proposed can integrate biofuels production into a biorefinery scheme in which the major components of poplar wood can be converted into value-added products.

  14. Alkaline peroxide pulping of oil palm empty fruit bunch by variation of chemical strength

    NASA Astrophysics Data System (ADS)

    Dermawan, Yunita Megasari; Ghazali, Arniza; Daud, Wan Rosli Wan; Lazin, Mohd Azli Khairil Mat

    2012-09-01

    Papers produced from oil palm empty fruit bunches (EFB) via Alkaline Peroxide Pulping (APP) was preceded by three main steps; dewaxing of EFB, alkaline peroxide (AP) impregnation into EFB and refining of biomass to generate pulp. The experiment was carried by varying chemical level and number of impregnation stages. For 2:2.5% AP level, two-stage impregnation improved hand sheets tear index by 45%, 164% boost in tensile index, 26% enhancement in zero span index and more than 5% in burst index. By applying 8:10% AP level, significant improvements were gained at the third and fourth stages of AP impregnation. Although there was no significant change in hand sheet strength with multiple impregnation for 4:5% AP level, improvement in brightness of hand sheets was apparent, analogous to the effect of increasing AP level. The found paper properties development show that alkaline peroxide pulping of EFB could be adapted to various targeted properties by adjustment of AP level and impregnation stages.

  15. Alkaline-assisted screw press pretreatment affecting enzymatic hydrolysis of wheat straw.

    PubMed

    Yan, Qingqi; Wang, Yumei; Rodiahwati, Wawat; Spiess, Antje; Modigell, Michael

    2017-02-01

    Screw press processing of biomass can be considered as a suitable mechanically based pretreatment for biofuel production since it disrupts the structure of lignocellulosic biomass with high shear and pressure forces. The combination with chemical treatment has been suggested to increase the conversion of lignocellulosic biomass to fermentable sugars. Within the study, the synergetic effect of alkaline (sodium hydroxide, NaOH) soaking and screw press pretreatment on wheat straw was evaluated based on, e.g., sugar recovery and energy efficiency. After alkaline soaking (at 0.1 M for 30 min) and sequential screw press pretreatment with various screw press configurations and modified screw barrel, the lignin content of pretreated wheat straw was quantified. In addition, the structure of pretreated wheat straw was investigated by scanning electron microscopy and measurement of specific surface area. It could be shown that removal of lignin is more important than increase of surface area of the biomass to reach a high sugar recovery. The rate constant of the enzymatic hydrolysis increased from 1.1 × 10(-3) 1/h for the non-treated material over 2.3 × 10(-3) 1/h for the alkaline-soaked material to 26.9 × 10(-3) 1/h for alkaline-assisted screw press pretreated material, indicating a nearly 25-fold improvement of the digestibility by the combined chemo-mechanical pretreatment. Finally, the screw configuration was found to be an important factor for improving the sugar recovery and for reducing the specific energy consumption of the screw press pretreatment.

  16. Optimization study on the hydrogen peroxide pretreatment and production of bioethanol from seaweed Ulva prolifera biomass.

    PubMed

    Li, Yinping; Cui, Jiefen; Zhang, Gaoli; Liu, Zhengkun; Guan, Huashi; Hwang, Hueymin; Aker, Winfred G; Wang, Peng

    2016-08-01

    The seaweed Ulva prolifera, distributed in inter-tidal zones worldwide, contains a large percentage of cellulosic materials. The technical feasibility of using U. prolifera residue (UPR) obtained after extraction of polysaccharides as a renewable energy resource was investigated. An environment-friendly and economical pretreatment process was conducted using hydrogen peroxide. The hydrogen peroxide pretreatment improved the efficiency of enzymatic hydrolysis. The resulting yield of reducing sugar reached a maximum of 0.42g/g UPR under the optimal pretreatment condition (hydrogen peroxide 0.2%, 50°C, pH 4.0, 12h). The rate of conversion of reducing sugar in the concentrated hydrolysates to bioethanol reached 31.4% by Saccharomyces cerevisiae fermentation, which corresponds to 61.7% of the theoretical maximum yield. Compared with other reported traditional processes on Ulva biomass, the reducing sugar and bioethanol yield are substantially higher. Thus, hydrogen peroxide pretreatment is an effective enhancement of the process of bioethanol production from the seaweed U. prolifera.

  17. 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.

  18. Enhancement of the enzymatic digestibility of sugarcane bagasse by steam pretreatment impregnated with hydrogen peroxide.

    PubMed

    Rabelo, Sarita Cândida; Vaz Rossell, Carlos Eduardo; de Moraes Rocha, George Jackson; Zacchi, Guido

    2012-01-01

    Sugarcane bagasse was subjected to steam pretreatment impregnated with hydrogen peroxide. Analyses were performed using 2(3) factorial designs and enzymatic hydrolysis was performed at two different solid concentrations and with washed and unwashed material to evaluate the importance of this step for obtaining high cellulose conversion. Similar cellulose conversion were obtained at different conditions of pretreatment and hydrolysis. When the cellulose was hydrolyzed using the pretreated material in the most severe conditions of the experimental design (210 °C, 15 min and 1.0% hydrogen peroxide), and using 2% (w/w) water-insoluble solids (WIS), and 15 FPU/g WIS, the cellulose conversion was 86.9%. In contrast, at a milder pretreatment condition (190 °C, 15 min and 0.2% hydrogen peroxide) and industrially more realistic conditions of hydrolysis (10% WIS and 10 FPU/g WIS), the cellulose conversion reached 82.2%. The step of washing the pretreated material was very important to obtain high concentrations of fermentable sugars.

  19. Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment.

    PubMed

    Gurram, Raghu Nandan; Al-Shannag, Mohammad; Lecher, Nicholas Joshua; Duncan, Shona M; Singsaas, Eric Lawrence; Alkasrawi, Malek

    2015-09-01

    In this study we investigated the technical feasibility of convert paper mill sludge into fuel ethanol. This involved the removal of mineral fillers by using either chemical pretreatment or mechanical fractionation to determine their effects on cellulose hydrolysis and fermentation to ethanol. In addition, we studied the effect of cationic polyelectrolyte (as accelerant) addition and hydrogen peroxide pretreatment on enzymatic hydrolysis and fermentation. We present results showing that removing the fillers content (ash and calcium carbonate) from the paper mill sludge increases the enzymatic hydrolysis performance dramatically with higher cellulose conversion at faster rates. The addition of accelerant and hydrogen peroxide pretreatment further improved the hydrolysis yields by 16% and 25% (g glucose / g cellulose), respectively with the de-ashed sludge. The fermentation process of produced sugars achieved up to 95% of the maximum theoretical ethanol yield and higher ethanol productivities within 9h of fermentation.

  20. Two-stage alkaline-enzymatic pretreatments to enhance biohydrogen production from sunflower stalks.

    PubMed

    Monlau, Florian; Trably, Eric; Barakat, Abdellatif; Hamelin, Jérôme; Steyer, Jean-Philippe; Carrere, Hélène

    2013-01-01

    Because of their rich composition in carbohydrates, lignocellulosic residues represent an interesting source of biomass to produce biohydrogen by dark fermentation. Nevertheless, pretreatments should be applied to enhance the solubilization of holocelluloses and increase their further conversion into biohydrogen. The aim of this study was to investigate the effect of thermo-alkaline pretreatment alone and combined with enzymatic hydrolysis to enhance biohydrogen production from sunflower stalks. A low increase of hydrogen potentials from 2.3 ± 0.9 to 4.4 ± 2.6 and 20.6 ± 5.6 mL of H2 g(-1) of volatile solids (VS) was observed with raw sunflower stalks and after thermo-alkaline pretreatment at 55 °C, 24 h, and 4% NaOH and 170 °C, 1 h, and 4% NaOH, respectively. Enzymatic pretreatment alone showed an enhancement of the biohydrogen yields to 30.4 mL of H2 g(-1) of initial VS, whereas it led to 49 and 59.5 mL of H2 g(-1) of initial VS when combined with alkaline pretreatment at 55 and 170 °C, respectively. Interestingly, a diauxic effect was observed with sequential consumption of sugars by the mixed cultures during dark fermentation. Glucose was first consumed, and once glucose was completely exhausted, xylose was used by the microorganisms, mainly related to Clostridium species.

  1. Optimization of alkaline pretreatment of coffee pulp for production of bioethanol.

    PubMed

    Menezes, Evandro G T; do Carmo, Juliana R; Alves, José Guilherme L F; Menezes, Aline G T; Guimarães, Isabela C; Queiroz, Fabiana; Pimenta, Carlos J

    2014-01-01

    The use of lignocellulosic raw materials in bioethanol production has been intensively investigated in recent years. However, for efficient conversion to ethanol, many pretreatment steps are required prior to hydrolysis and fermentation. Coffee stands out as the most important agricultural product in Brazil and wastes such as pulp and coffee husk are generated during the wet and dry processing to obtain green grains, respectively. This work focused on the optimization of alkaline pretreatment of coffee pulp with the aim of making its use in the alcoholic fermentation. A central composite rotatable design was used with three independent variables: sodium hydroxide and calcium hydroxide concentrations and alkaline pretreatment time, totaling 17 experiments. After alkaline pretreatment the concentration of cellulose, hemicellulose, and lignin remaining in the material, the subsequent hydrolysis of the cellulose component and its fermentation of substrate were evaluated. The results indicated that pretreatment using 4% (w/v) sodium hydroxide solution, with no calcium hydroxide, and 25 min treatment time gave the best results (69.18% cellulose remaining, 44.15% hemicelluloses remaining, 25.19% lignin remaining, 38.13 g/L of reducing sugars, and 27.02 g/L of glucose) and produced 13.66 g/L of ethanol with a yield of 0.4 g ethanol/g glucose.

  2. Low-heat alkaline pretreatment of biomass for dairy anaerobic codigestion.

    PubMed

    Jin, Guang; Bierma, Tom

    2014-01-01

    In this research, low-heat alkaline pretreatment was evaluated to determine the extent to which urban landscape waste (yard waste), corn stover, and switchgrass could be codigested under conditions typical of US farm-based anaerobic digestion (AD). Waste heat from combined heat and power (CHP) units associated with AD could make such pretreatment economical. Short-term batch digestion studies and 8-week continuous-feed studies were used to screen and evaluate various pretreatment conditions. Results indicate that maple and oak leaves did not digest well, even with pretreatment. Pretreatment did improve digestion of corn leaves and stalks as well as switchgrass. However, these materials also digested reasonably well even without pretreatment. No digester operational problems were observed during continuous-feed studies of intermittently stirred bench top digesters, but optimal levels of alkali, temperature, and pretreatment time may be specific to the feedstock, particle size, and digester loading rate. Results suggest that some common lignocellulosic biomass materials, such as corn stover and switchgrass, could be successfully codigested in many existing farm-based digesters. Interestingly, without pretreatment, switchgrass digestion improved over 20-fold when digested with seed culture from a dairy digester compared to seed culture from a municipal digester, suggesting that culture acclimation could be as important as pretreatment in improving digestion of specific lignocellulosic feedstocks.

  3. Structural changes and enzymatic response of Napier grass (Pennisetum purpureum) stem induced by alkaline pretreatment.

    PubMed

    Phitsuwan, Paripok; Sakka, Kazuo; Ratanakhanokchai, Khanok

    2016-10-01

    Napier grass is a promising energy crop in the tropical region. Feasible alkaline pretreatment technologies, including NaOH, Ca(OH)2, NH3, and alkaline H2O2 (aH2O2), were used to delignify lignocellulose with the aim of improving glucose recovery from Napier grass stem cellulose via enzymatic saccharification. The influences of the pretreatments on structural alterations were examined using SEM, FTIR, XRD, and TGA, and the relationships between these changes and the enzymatic digestibility of cellulose were addressed. The extensive removal of lignin (84%) in NaOH-pretreated fibre agreed well with the high glucan conversion rate (94%) by enzymatic hydrolysis, while the conversion rates for fibre pretreated with Ca(OH)2, NH3, and aH2O2 approached 60%, 51%, and 42%, respectively. The substantial solubilisation of lignin created porosity, allowing increased cellulose accessibility to cellulases in NaOH-pretreated fibre. In contrast, high lignin content, lignin redeposition on the surface, and residual internal lignin and hemicellulose impeded enzymatic performance in Ca(OH)2-, NH3-, and aH2O2-pretreated fibres, respectively.

  4. Comparison of liquid hot water and alkaline pretreatments of giant reed for improved enzymatic digestibility and biogas energy production.

    PubMed

    Jiang, Danping; Ge, Xumeng; Zhang, Quanguo; Li, Yebo

    2016-09-01

    Liquid hot water (LHW) and alkaline pretreatments of giant reed biomass were compared in terms of digestibility, methane production, and cost-benefit efficiency for electricity generation via anaerobic digestion with a combined heat and power system. Compared to LHW pretreatment, alkaline pretreatment retained more of the dry matter in giant reed biomass solids due to less severe conditions. Under their optimal conditions, LHW pretreatment (190°C, 15min) and alkaline pretreatment (20g/L of NaOH, 24h) improved glucose yield from giant reed by more than 2-fold, while only the alkaline pretreatment significantly (p<0.05) increased cumulative methane yield (by 63%) over that of untreated biomass (217L/kgVS). LHW pretreatment obtained negative net electrical energy production due to high energy input. Alkaline pretreatment achieved 27% higher net electrical energy production than that of non-pretreatment (3859kJ/kg initial total solids), but alkaline liquor reuse is needed for improved net benefit.

  5. The effect of alkaline pretreatment methods on cellulose structure and accessibility

    DOE PAGES

    Bali, Garima; Meng, Xianzhi; Deneff, Jacob I.; ...

    2014-11-24

    The effects of different alkaline pretreatments on cellulose structural features and accessibility are compared and correlated with the enzymatic hydrolysis of Populus. The pretreatments are shown to modify polysaccharides and lignin content to enhance the accessibility for cellulase enzymes. The highest increase in the cellulose accessibility was observed in dilute sodium hydroxide, followed by methods using ammonia soaking and lime (Ca(OH)2). The biggest increase of cellulose accessibility occurs during the first 10 min of pretreatment, with further increases at a slower rate as severity increases. Low temperature ammonia soaking at longer residence times dissolved a major portion of hemicellulose andmore » exhibited higher cellulose accessibility than high temperature soaking. Moreover, the most significant reduction of degree of polymerization (DP) occurred for dilute sodium hydroxide (NaOH) and ammonia pretreated Populus samples. The study thus identifies important cellulose structural features and relevant parameters related to biomass recalcitrance.« less

  6. The effect of alkaline pretreatment methods on cellulose structure and accessibility

    SciTech Connect

    Bali, Garima; Meng, Xianzhi; Deneff, Jacob I.; Sun, Qining; Ragauskas, Arthur J.

    2014-11-24

    The effects of different alkaline pretreatments on cellulose structural features and accessibility are compared and correlated with the enzymatic hydrolysis of Populus. The pretreatments are shown to modify polysaccharides and lignin content to enhance the accessibility for cellulase enzymes. The highest increase in the cellulose accessibility was observed in dilute sodium hydroxide, followed by methods using ammonia soaking and lime (Ca(OH)2). The biggest increase of cellulose accessibility occurs during the first 10 min of pretreatment, with further increases at a slower rate as severity increases. Low temperature ammonia soaking at longer residence times dissolved a major portion of hemicellulose and exhibited higher cellulose accessibility than high temperature soaking. Moreover, the most significant reduction of degree of polymerization (DP) occurred for dilute sodium hydroxide (NaOH) and ammonia pretreated Populus samples. The study thus identifies important cellulose structural features and relevant parameters related to biomass recalcitrance.

  7. Comparative performance of enzymatic and combined alkaline-enzymatic pretreatments on methane production from ensiled sorghum forage.

    PubMed

    Rollini, Manuela; Sambusiti, Cecilia; Musatti, Alida; Ficara, Elena; Retinò, Isabella; Malpei, Francesca

    2014-12-01

    This study investigated the effect of enzymatic and combined alkaline-enzymatic pretreatments on chemical composition and methane production from ensiled sorghum forage. Four commercial enzymatic preparations were tested and the two yielding the highest sugars release were added to evaluate any hydrolytic effect on both untreated and alkaline pretreated samples. In the combined alkaline-enzymatic pretreatment trials, the highest sugar release was found with Primafast and BGL preparations (added at a final concentration 0.12 and 0.20 mL/g TS, respectively), with a total monomeric content of 12 and 6.5 g/L. Fibre composition analysis confirmed that the combined alkaline-enzymatic pretreatment led to cellulose (up to 32 %) and hemicelluloses (up to 56 %) solubilisation, compared to the enzymatic pretreatment alone. BMP tests were performed on both untreated and pretreated samples, and time courses of methane production were fitted. Both enzymatic and combined alkaline-enzymatic pretreatment led to a methane production increase (304 and 362 mL CH4/g VS), compared to that of untreated sorghum (265 mL CH4/g VS), as  +15 and  +37 %, respectively. Moreover, higher specific methane production rates, compared to that of untreated sorghum (20.31 mL CH4/g VS/d), were obtained by applying the enzymatic and combined alkaline-enzymatic pretreatment (33.94 and 31.65 mL CH4/g VS/d), respectively.

  8. Hydrogen peroxide pre-treatment induces salt-stress acclimation in maize plants.

    PubMed

    de Azevedo Neto, André Dias; Prisco, José Tarquinio; Enéas-Filho, Joaquim; Medeiros, Jand-Venes Rolim; Gomes-Filho, Enéas

    2005-10-01

    The effect of exogenously applied H2O2 on salt stress acclimation was studied with regard to plant growth, lipid peroxidation, and activity of antioxidative enzymes in leaves and roots of a salt-sensitive maize genotype. Pre-treatment by addition of 1 microM H2O2 to the hydroponic solution for 2 days induced an increase in salt tolerance during subsequent exposure to salt stress. This was evidenced by plant growth, lipid peroxidation and antioxidative enzymes measurements. In both leaves and roots the variations in lipid peroxidation and antioxidative enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase, and catalase) activities of both acclimated and unacclimated plants, suggest that differences in the antioxidative enzyme activities may, at least in part, explain the increased tolerance of acclimated plants to salt stress, and that H2O2 metabolism is involved as signal in the processes of maize salt acclimation.

  9. Effect of ultrasonic pre-treatment of thermomechanical pulp on hydrogen peroxide bleaching

    NASA Astrophysics Data System (ADS)

    Loranger, E.; Charles, A.; Daneault, C.

    2012-12-01

    Ultrasound pre-treatments of softwood TMP had been carried to evaluate its impact on the efficiency of hydrogen peroxide bleaching. The trials were performed after a factorial design of experiment using frequency, power and time as variables. The experiments were conducted in an ultrasonic bath and then bleached with hydrogen peroxide. Measurements such as brightness, L*A*B* color system coordinate, residual hydrogen peroxide and metal content were evaluated on bleached pulp. The results indicate that the effect of ultrasonic treatment on brightness was dependent on the ultrasound frequency used; the brightness increased slightly at 68 kHz and decreased at 40 and 170 kHz. These results were correlated to the ultrasound effect on the generation of transition metals (copper, iron and manganese) which are responsible for catalytic decomposition of hydrogen peroxide. The influence of metal interference was minimized by using a chelating agent such as diethylene triamine pentaacetic acid (DTPA). With the results obtained in this study we have identified a set of option conditions, e.g. 1000 W, 40 kHz, 1.5 % consistency and 0.2% addition of DTPA prior to the bleaching stage (after ultrasonic pre-treatment) who improve brightness by 2.5 %ISO.

  10. Influence of alkaline hydrogen peroxide pre-hydrolysis on the isolation of microcrystalline cellulose from oil palm fronds.

    PubMed

    Owolabi, Abdulwahab F; Haafiz, M K Mohamad; Hossain, Md Sohrab; Hussin, M Hazwan; Fazita, M R Nurul

    2017-02-01

    In the present study, microcrystalline cellulose (MCC) was isolated from oil palm fronds (OPF) using chemo-mechanical process. Wherein, alkaline hydrogen peroxide (AHP) was utilized to extract OPF fibre at different AHP concentrations. The OPF pulp fibre was then bleached with acidified sodium chlorite solution followed by the acid hydrolysis using hydrochloric acid. Several analytical methods were conducted to determine the influence of AHP concentration on thermal properties, morphological properties, microscopic and crystalline behaviour of isolated MCC. Results showed that the MCC extracted from OPF fibres had fibre diameters of 7.55-9.11nm. X-ray diffraction (XRD) analyses revealed that the obtained microcrystalline fibre had both celluloses I and cellulose II polymorphs structure, depending on the AHP concentrations. The Fourier transmission infrared (FTIR) analyses showed that the AHP pre-hydrolysis was successfully removed hemicelluloses and lignin from the OPF fibre. The crystallinity of the MCC was increased with the AHP concentrations. The degradation temperature of MCC was about 300°C. The finding of the present study showed that pre-treatment process potentially influenced the quality of the isolation of MCC from oil palm fronds.

  11. Lignin isolation process from rice husk by alkaline hydrogen peroxide: Lignin and silica extracted

    NASA Astrophysics Data System (ADS)

    Ma'ruf, Anwar; Pramudono, Bambang; Aryanti, Nita

    2017-03-01

    Biomass is one of abundance resources in the world. Biomass consists of three main materials such as cellulose, hemicelluloses and lignin. Therefore, biomass can be referred to lignocellulosic material. Both the cellulose and hemicelluloses fractions are polymers of sugars, and thereby a potential source of fermentable sugars, or other processes that convert sugars into products. Lignin is a polymer compound which contains of phenolic compounds. Rice husk is one of biomass, which has high contain of lignin. Rice husk has special characteristics because of silica content. The aim of this paper is to analyze lignin and silica extracted during lignin isolation process of rice husk using alkaline hydrogen peroxide. Three main variables such as solvent/solid ratio, concentration of hydrogen peroxide and pH of the mixture are studied. The optimum conditions for lignin isolation are at solvent/solid ratio 9:1 ml/gr, hydrogen peroxide concentration of 1.5%v and pH of the mixture of 11.

  12. 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.

  13. 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

  14. Alkaline pretreatment methods followed by acid hydrolysis of Saccharum spontaneum for bioethanol production.

    PubMed

    Chaudhary, Gaurav; Singh, Lalit Kumar; Ghosh, Sanjoy

    2012-11-01

    Different alkaline pretreatment methods (NaOH, NaOH+10% urea and aqueous ammonia) were optimized for maximum delignification of Saccharum spontaneum at 30°C. Maximum delignification were obtained as 47.8%, 51% and 48% from NaOH (7% NaOH, 48h, and 10% biomass loading), NaOH+urea (7% NaOH+10% urea, 48 h and 10% biomass loading) and 30% ammonia (40 days and 10% biomass loading) respectively. H(2)SO(4) 60% (v/v), 10% biomass loading at 30°C for 4h, were optimized conditions to solubilize the cellulose and hemicellulose from solid residue obtained after different optimized alkaline pretreatments. Slurry thus obtained was diluted to obtain final acid concentration of 10% (v/v) for real hydrolysis of cellulose and hemicellulose at 100°C for 1h. Among all pretreatment methods applied, the best result 0.58 g (85%) reducing sugars/g of initial biomass after acid hydrolysis was obtained from aqueous ammonia pretreated biomass. Scheffersomyces stipitis CBS6054 was used to ferment the hydrolysate; ethanol yield (Y(p/s)) and productivity (r(p)) were found to be 0.35 g/g and 0.22 g/L/h respectively.

  15. 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

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

    PubMed

    Singh, Joginder; Suhag, Meenakshi; Dhaka, Anil

    2015-03-06

    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.

  17. Improved methane production from waste activated sludge with low organic content by alkaline pretreatment at pH 10.

    PubMed

    Feng, L Y; Yang, L Q; Zhang, L X; Chen, H L; Chen, J

    2013-01-01

    Sludge with low organic content always results in an unsatisfactory performance, even failure of anaerobic digestion. The alkaline pretreatment effect on anaerobic digestion of sludge with low organic content has seldom been studied although it gives many benefits for sludge with high organic content. In this study the influence of alkaline pretreatment (pH 10, an effective alkaline pH) on the solubilization and methane production from waste activated sludge (WAS) with low organic content was investigated. Results from biochemical methane potential (BMP) experiments showed that anaerobic biodegradability of WAS was greatly improved by alkaline pretreatment at pH 10. Methane production from the current WAS under conditions of pretreatment time 4 h and digestion time 15 d was 139.6 mL/g VS (volatile solids), much higher than that from the unpretreated WAS with digestion time of 20 d (75.2 mL/g VS). Also, the solubilization of WAS was significantly accelerated by alkaline pretreatment. Mechanism exploration indicated that the general activities of anaerobic microorganisms, specific activities of key enzymes and the amounts of methanogens were enhanced by alkaline pretreatment at pH 10, showing good agreement with methane production.

  18. Fungal treatment of cornstalks enhances the delignification and xylan loss during mild alkaline pretreatment and enzymatic digestibility of glucan.

    PubMed

    Yu, Hongbo; Du, Wanqing; Zhang, Ji; Ma, Fuying; Zhang, Xiaoyu; Zhong, Weixin

    2010-09-01

    Fungal treatment with Irpex lacteus was used to enhance the delignification and xylan loss during mild alkaline pretreatment and subsequent enzymatic conversion in this research. The 15-day bio-treatment can modify the lignin structure and increase losses of lignin (from 75.67% to 80.00%) and xylan (from 40.68% to 51.37%) during alkaline pretreatment, making the enzymatic conversion more efficient. The high digestibility of glucan can be obtained after the bio-treatment and alkaline pretreatment at near room-temperature (30 degrees C), and the maximum digestibility increased 14% in comparison with that after the sole alkaline pretreatment. The bio-treatment enhanced delignification and glucan digestibility more significantly when the alkaline pretreatment was performed at lower severity. Additionally, Nuclei Growth model with a time-dependent rate constant can describe well the delignification and xylan loss. Results indicated that the bio-treatment increased the rate constant of initial reaction, but accelerated the decline of rate constant during alkaline pretreatment.

  19. 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...

  20. Mechanistic insights into the bleaching of melanin by alkaline hydrogen peroxide.

    PubMed

    Smith, R A W; Garrett, B; Naqvi, K R; Fülöp, A; Godfrey, S P; Marsh, J M; Chechik, V

    2017-03-18

    This work aims to determine the roles of reactive oxygen species HO∙ and HO2(-) in the bleaching of melanins by alkaline hydrogen peroxide. Experiments using melanosomes isolated from human hair indicated that the HO∙ radical generated in the outside solution does not contribute significantly to bleaching. However, studies using soluble Sepia melanin demonstrated that both HO2(-) and HO∙ will individually bleach melanin. Additionally, when both oxidants are present, bleaching is increased dramatically in both rate and extent. Careful experimental design enabled the separation of the roles and effects of these key reactive species, HO∙ and HO2(-). Rationalisation of the results presented, and review of previous literature, allowed the postulation of a simplified general scheme whereby the strong oxidant HO∙ is able to pre-oxidise melanin units to o-quinones enabling more facile ring opening by the more nucleophilic HO2(-). In this manner the efficiency of the roles of both species is maximised.

  1. Characterisation of mechanical pulp fines from alkaline peroxide pulping of EFB

    NASA Astrophysics Data System (ADS)

    Kamaludin, Nurul Hasanah; Ghazali, Arniza; Daud, Wan Rosli Wan

    2012-09-01

    EFB (empty fruit bunch) was subjected to alkaline peroxide pulping for generation of fibrous mass as raw material for the making of pulp-based products. During refining, co-produced fines were collected by fractionation on square-mesh screens of 200-, 250-, 300- and 400- mesh sizes, placed at the refining discharge by order of increasing mesh. Each set of the produced paper was incorporated with 12% fines for microscopic analysis. It appears that sheared vessel elements and fibrils were predominant and they make up the mass rendering collapsibility of cell wall for good product formation. The study acknowledged the form of fines functioning as natural filler in pulp network and worthy of utilization for reduction of total suspended solid.

  2. Concurrent calcium peroxide pretreatment and wet storage of water hyacinth for fermentable sugar production.

    PubMed

    Cheng, Yu-Shen; Chen, Kuan-Yu; Chou, Tzung-Han

    2015-01-01

    In the present study, a novel concurrent process of pretreatment and wet storage was developed and investigated by applying calcium peroxide for preservation and conversion of fresh water hyacinth biomass to fermentable sugars. The effects of CaO2 loading concentration and moisture content on the lignin reduction, carbohydrate preservation and enzymatic saccharification of water hyacinth biomass were evaluated by experimental design using a response surface methodology. The data showed that the concurrent process could conserve 70% carbohydrates and remove 40% lignin from biomass of water hyacinth at the best condition in this study. The enzymatic digestibility and reducing sugar yield from the best condition of concurrent process were around 93% and 325mg/g (dry weight) of fresh biomass, respectively. The result suggested that the concurrent process developed in this work could be a potential alternative to consolidate the pretreatment and storage of aquatic plant biomass for fermentable sugar production.

  3. Surface characterization and chemical analysis of bamboo substrates pretreated by alkali hydrogen peroxide.

    PubMed

    Song, Xueping; Jiang, Yan; Rong, Xianjian; Wei, Wei; Wang, Shuangfei; Nie, Shuangxi

    2016-09-01

    The surface characterization and chemical analysis of bamboo substrates by alkali hydrogen peroxide pretreatment (AHPP) were investigated in this study. The results tended to manifest that AHPP prior to enzymatic and chemical treatment was potential for improving accessibility and reactivity of bamboo substrates. The inorganic components, organic solvent extractives and acid-soluble lignin were effectively removed by AHPP. X-ray photoelectron spectroscopy (XPS) analysis indicated that the surface of bamboo chips had less lignin but more carbohydrate after pre-treatment. Fiber surfaces became etched and collapsed, and more pores and debris on the substrate surface were observed with Scanning Electron Microscopy (SEM). Brenauer-Emmett-Teller (BET) results showed that both of pore volume and surface area were increased after AHPP. Although XRD analysis showed that AHPP led to relatively higher crystallinity, pre-extraction could overall enhance the accessibility of enzymes and chemicals into the bamboo structure.

  4. Improvement of radio frequency (RF) heating-assisted alkaline pretreatment on four categories of lignocellulosic biomass.

    PubMed

    Wang, Xiaofei; Taylor, Steven; Wang, Yifen

    2016-10-01

    Pretreatment plays an important role in making the cellulose accessible for enzyme hydrolysis and subsequent conversion because it destroys more or less resistance and recalcitrance of biomass. Radio frequency (RF)-assisted dielectric heating was utilized in the alkaline pretreatment on agricultural residues (corn stover), herbaceous crops (switchgrass), hardwood (sweetgum) and softwood (loblolly pine). Pretreatment was performed at 90 °C with either RF or traditional water bath (WB) heating for 1 h after overnight soaking in NaOH solution (0.2 g NaOH/g Biomass). Pretreated materials were characterized by chemical compositional analysis, enzyme hydrolysis, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The glucan yields of RF-heated four categories of hydrolysates were 89.6, 72.6, 21.7, and 9.9 %. Interestingly, RF heating raised glucan yield on switchgrass and sweetgum but not on corn stover or loblolly pine. The SEM images and FTIR spectra agreed with results of composition analysis and hydrolysis. GC-MS detected some compounds only from RF-heated switchgrass. These compounds were found by other researchers only in high-temperature (150-600 °C) and high-pressure pyrolysis processes.

  5. Ultrasound-assisted alkaline pretreatment of sugarcane bagasse for fermentable sugar production: optimization through response surface methodology.

    PubMed

    Velmurugan, Rajendran; Muthukumar, Karuppan

    2012-05-01

    Ultrasound-assisted alkaline pretreatment of sugarcane bagasse (SCB) for fermentable sugar production was carried out and the influence of particle size, liquid to solid ratio (LSR), NaOH concentration, temperature and sonication time on delignification and reducing sugar production was ascertained with Placket-Burman design. The best combination of each significant factor was determined by a central composite design (CCD) and optimum pretreatment conditions for maximum reducing sugar yield (96.27%) were particle size of 0.27 mm, LSR of 25 ml/g, NaOH concentration of 2.89% (w/v), temperature of 70.15°C and pretreatment time of 47.42 min. Under these conditions, 92.11% of theoretical reducing sugar yield was observed experimentally. The substantial reduction in pretreatment time and temperature with improved efficiency is the most attractive features of the ultrasound-assisted alkaline pretreatment.

  6. Alkaline pretreatment and the synergic effect of water and tetralin enhances the liquefaction efficiency of bagasse.

    PubMed

    Li, Zhixia; Cao, Jiangfei; Huang, Kai; Hong, Yaming; Li, Cunlong; Zhou, Xinxin; Xie, Ning; Lai, Fang; Shen, Fang; Chen, Congjin

    2015-02-01

    Bagasse liquefaction (BL) in water, tetralin, and water/tetralin mixed solvents (WTMS) was investigated, and effects of tetralin content in WTMS, temperature, and alkaline pretreatment of bagasse on liquefaction efficiency were studied. At 300°C, bagasse conversion in WTMS with tetralin content higher than 50 wt% was 86-87 wt%, whereas bagasse conversion in water or tetralin was 67 wt% or 84 wt%, respectively. Because the solid conversion from liquefaction in WTMS with tetralin content higher than 50 wt% was always higher than that in water or tetralin at temperatures between 250 and 300°C, a synergic effect between water and tetralin is suggested. Alkaline pretreatment of bagasse resulted in significantly higher conversion and heavy oil yield from BL in water or WTMS. The effect of deoxygenation by the present liquefaction method is demonstrated by lower oxygen contents (16.01-19.59 wt%) and higher heating values (31.9-34.8 MJ/kg) in the produced oils.

  7. Catalase plays a key role in salt stress acclimation induced by hydrogen peroxide pretreatment in maize.

    PubMed

    Gondim, Franklin Aragão; Gomes-Filho, Enéas; Costa, José Hélio; Mendes Alencar, Nara Lídia; Prisco, José Tarquinio

    2012-07-01

    Pretreatment in plants is recognized as a valuable strategy to stimulate plant defenses, leading to better plant development. This study evaluated the effects of H₂O₂ leaf spraying pretreatment on plant growth and investigated the antioxidative mechanisms involved in the response of maize plants to salt stress. It was found that salinity reduced maize seedling growth when compared to control conditions, and H₂O₂ foliar spraying was effective in minimizing this effect. Analysis of the antioxidative enzymes catalase (EC 1.11.1.6), guaiacol peroxidase (EC 1.11.1.7), ascorbate peroxidase (EC 1.11.1.1) and superoxide dismutase (EC 1.15.1.1) revealed that H₂O₂ spraying increased antioxidant enzyme activities. Catalase (CAT) was the most responsive of these enzymes to H₂O₂, with higher activity early (48 h) in the treatment, while guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) were responsive only at later stages (240 h) of treatment. Increased CAT activity appears linked to gene expression regulation. Lower malondialdehyde levels were detected in plants with higher CAT activity, which may result from the protective function of this enzyme. Overall, we can conclude that pretreatment with H₂O₂ leaf spraying was able to reduce the deleterious effects of salinity on seedling growth and lipid peroxidation. These responses could be attributed to the ability of H₂O₂ to induce antioxidant defenses, especially CAT activity.

  8. Au/n-ZnO rectifying contact fabricated with hydrogen peroxide pretreatment

    NASA Astrophysics Data System (ADS)

    Gu, Q. L.; Cheung, C. K.; Ling, C. C.; Ng, A. M. C.; Djurišić, A. B.; Lu, L. W.; Chen, X. D.; Fung, S.; Beling, C. D.; Ong, H. C.

    2008-05-01

    Au contacts were deposited on n-type ZnO single crystals with and without hydrogen peroxide pretreatment for the ZnO substrate. The Au/ZnO contacts fabricated on substrates without H2O2 pretreatment were Ohmic and those with H2O2 pretreatment were rectifying. With an aim of fabricating a good quality Schottky contact, the rectifying property of the Au/ZnO contact was systemically investigated by varying the treatment temperature and duration. The best performing Schottky contact was found to have an ideality factor of 1.15 and a leakage current of ˜10-7 A cm-2. A multispectroscopic study, including scanning electron microscopy, positron annihilation spectroscopy, deep level transient spectroscopy, x-ray photoelectron spectroscopy, and photoluminescence, showed that the H2O2 treatment removed the OH impurity and created Zn-vacancy related defects hence decreasing the conductivity of the ZnO surface layer, a condition favorable for forming good Schottky contact. However, the H2O2 treatment also resulted in a deterioration of the surface morphology, leading to an increase in the Schottky contact ideality factor and leakage current in the case of nonoptimal treatment time and temperature.

  9. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    NASA Astrophysics Data System (ADS)

    Hasvold, Øistein; Johansen, Kjell Håvard; Mollestad, Ole; Forseth, Sissel; Størkersen, Nils

    In 1993, The Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on an UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m.

  10. The production of glucose from corn stalk using hydrothermal process with pre-treatment ultrasound assisted alkaline

    NASA Astrophysics Data System (ADS)

    Yolanda, Dora; Prasutiyo, Indry; Trisanti, P. N.; Sumarno

    2015-12-01

    The production of glucose from corn stalk by using subcritical hydrothermal technology is studied in this work. Ultrasound-assisted alkaline delignification methods are used as pre-treatment. The corn stalk powder were pretreated with ultrasound-assisted alkaline (NaOH 2% w/w, solid to liquid ratio 1:22 w/v) at room temperature and 30 minutes. After pre-treatment, solid residue and liquid fractions are separated by filtration. Pretreated solids are further submitted to hydrothermal process for glucose production. Hydrothermal process was carried out at 100 Bar and 120°C in various times. The solid product was characterized by SEM and XRD. And liquid product was analysis using DNS method to determine percentage of glucose. From XRD analysis showed that crystallinity of material was lower than delignification product.

  11. Evaluation of microwave-assisted pretreatment of lignocellulosic biomass immersed in alkaline glycerol for fermentable sugars production.

    PubMed

    Diaz, Ana Belen; Moretti, Marcia Maria de Souza; Bezerra-Bussoli, Carolina; Carreira Nunes, Christiane da Costa; Blandino, Ana; da Silva, Roberto; Gomes, Eleni

    2015-06-01

    A pretreatment with microwave irradiation was applied to enhance enzyme hydrolysis of corn straw and rice husk immersed in water, aqueous glycerol or alkaline glycerol. Native and pretreated solids underwent enzyme hydrolysis using the extract obtained from the fermentation of Myceliophthora heterothallica, comparing its efficiency with that of the commercial cellulose cocktail Celluclast®. The highest saccharification yields, for both corn straw and rice husk, were attained when biomass was pretreated in alkaline glycerol, method that has not been previously reported in literature. Moreover, FTIR, TG and SEM analysis revealed a more significant modification in the structure of corn straw subjected to this pretreatment. Highest global yields were attained with the crude enzyme extract, which might be the result of its content in a great variety of hydrolytic enzymes, as revealed zymogram analysis. Moreover, its hydrolysis efficiency can be improved by its supplementation with commercial β-glucosidase.

  12. Enhancing methane production from waste activated sludge using a novel indigenous iron activated peroxidation pre-treatment process.

    PubMed

    Zhou, Xu; Wang, Qilin; Jiang, Guangming

    2015-04-01

    Methane production from anaerobic digestion of waste activated sludge (WAS) is limited by the slow hydrolysis rate and/or poor methane potential of WAS. This study presents a novel pre-treatment strategy based on indigenous iron (in WAS) activated peroxidation to enhance methane production from WAS. Pre-treatment of WAS for 30 min at 50mg H2O2/g total solids (dry weight) and pH 2.0 (iron concentration in WAS was 7 mg/g TS) substantially enhanced WAS solubilization. Biochemical methane potential tests demonstrated that methane production was improved by 10% at a digestion time of 16d after incorporating the indigenous iron activated peroxidation pre-treatment. Model-based analysis indicated that indigenous iron activated peroxidation pre-treatment improved the methane potential by 13%, whereas the hydrolysis rate was not significantly affected. The economic analysis showed that the proposed pre-treatment method can save the cost by $112,000 per year in a treatment plant with a population equivalent of 300,000.

  13. Alkaline-sulfite pretreatment and use of surfactants during enzymatic hydrolysis to enhance ethanol production from sugarcane bagasse.

    PubMed

    Mesquita, Jéssica Faria; Ferraz, André; Aguiar, André

    2016-03-01

    Sugarcane bagasse is a by-product from the sugar and ethanol industry which contains approximately 70 % of its dry mass composed by polysaccharides. To convert these polysaccharides into fuel ethanol it is necessary a pretreatment step to increase the enzymatic digestibility of the recalcitrant raw material. In this work, sugarcane bagasse was pretreated by an alkaline-sulfite chemithermomechanical process for increasing its enzymatic digestibility. Na2SO3 and NaOH ratios were fixed at 2:1, and three increasing chemical loads, varying from 4 to 8 % m/m Na2SO3, were used to prepare the pretreated materials. The increase in the alkaline-sulfite load decreased the lignin content in the pretreated material up to 35.5 % at the highest chemical load. The pretreated samples presented enhanced glucose yields during enzymatic hydrolysis as a function of the pretreatment severity. The maximum glucose yield (64 %) was observed for the samples pretreated with the highest chemical load. The use of 2.5 g l(-1) Tween 20 in the hydrolysis step further increased the glucose yield to 75 %. Semi-simultaneous hydrolysis and fermentation of the pretreated materials indicated that the ethanol yield was also enhanced as a function of the pretreatment severity. The maximum ethanol yield was 56 ± 2 % for the sample pretreated with the highest chemical load. For the sample pretreated with the lowest chemical load (2 % m/m NaOH and 4 % m/m Na2SO3), adding Tween 20 during the hydrolysis process increased the ethanol yield from 25 ± 3 to 39.5 ± 1 %.

  14. Determination of the equilibrium formation constants of two U(VI)-peroxide complexes at alkaline pH.

    PubMed

    Meca, S; Martínez-Torrents, A; Martí, V; Giménez, J; Casas, I; de Pablo, J

    2011-08-21

    The formation of uranyl-peroxide complexes was studied at alkaline media by using UV-Visible spectrophotometry and the STAR code. Two different complexes were found at a H(2)O(2)/U(VI) ratio lower than 2. A graphical method was used in order to obtain the formation constants of such complexes and the STAR program was used to refine the formation constants values because of its capacity to treat multiwavelength absorbance data and refining equilibrium constants. The values obtained for the two complexes identified were: UO(2)(2+) + H(2)O(2) + 4OH(-) <−> UO(2)(O(2))(OH)(2)(2-) + 2H(2)O: log β°(1,1,4) = 28.1 ± 0.1 (1). UO(2)(2+) + 2H(2)O(2) + 6OH(-) <−> UO(2)(O(2))(2)(OH)(2)(4-) + 4H(2)O: log β°(1,2,6) = 36.8 ± 0.2 (2). At hydrogen peroxide concentrations higher than 10(-5) mol dm(-3), and in the absence of carbonate, the UO(2)(O(2))(2)(OH)(2)(4-) complex is predominant in solution, indicating the significant peroxide affinity of peroxide ions for uranium and the strong complexes of uranium(VI) with peroxide.

  15. Synergistic Effect of Atmospheric Pressure Plasma Pre-Treatment on Alkaline Etching of Polyethylene Terephthalate Fabrics and Films

    NASA Astrophysics Data System (ADS)

    A. Elabid Amel, E.; Guo, Ying; Shi, Jianjun; Ding, Ke; Zhang, Jing

    2016-04-01

    Dyeing of PET materials by traditional methods presents several problems. Plasma technology has received enormous attention as a solution for the environmental problems related with textile surface modifications, and there has been a rapid development and commercialization of plasma technology over the past decade. In this work, the synergistic effect of atmospheric pressure plasma on alkaline etching and deep coloring of dyeing properties on polyethylene terephthalate (PET) fabrics and films was investigated. The topographical changes of the PET surface were investigated by atomic force microscopy (AFM) images, which revealed a smooth surface morphology of the untreated sample whereas a high surface roughness for the plasma and/or alkaline treated samples. The effects of atmospheric pressure plasma on alkaline etching of the structure and properties of PET were investigated by means of differential scanning calorimetry (DSC), the main objective of performing DSC was to investigate the effect of the plasma pre-treatment on the Tg and Tm. Using a tensile strength tester YG065H and following a standard procedure the maximum force and elongation at maximum force of PET materials was investigated. Oxygen and argon plasma pre-treatment was found to increase the PET fabric weight loss rate. The color strength of PET fabrics was increased by various plasma pre-treatment times. The penetration of plasma and alkaline reactive species deep into the PET structure results in better dyeability and leaves a significant effect on the K/S values of the plasma pre-treated PET. It indicated that plasma pre-treatment has a great synergistic effect with the alkaline treatment of PET.

  16. Enzymatic digestion of alkaline-sulfite pretreated sugar cane bagasse and its correlation with the chemical and structural changes occurring during the pretreatment step.

    PubMed

    Mendes, Fernanda M; Laurito, Debora F; Bazzeggio, Mariana; Ferraz, André; Milagres, Adriane M F

    2013-01-01

    Sugar cane bagasse is recalcitrant to enzymatic digestion, which hinders the efficient conversion of its polysaccharides into fermentable sugars. Alkaline-sulfite pretreatment was used to overcome the sugar cane bagasse recalcitrance. Chemical and structural changes that occurred during the pretreatment were correlated with the efficiency of the enzymatic digestion of the polysaccharides. The first 30 min of pretreatment, which removed approximately half of the initial lignin and 30% of hemicellulose seemed responsible for a significant enhancement of the cellulose conversion level, which reached 64%. After the first 30 min of pretreatment, delignification increased slightly, and hemicellulose removal was not enhanced; however, acid groups continued to be introduced into the residual lignin. Water retention values were 145% to the untreated bagasse and 210% to the bagasse pretreated for 120 min and fiber widths increased from 10.4 to 30 μm, respectively. These changes were responsible for an additional increase in the efficiency of enzymatic hydrolysis of the cellulose, which reached 92% with the 120 min pretreated sample.

  17. Oil oxidation in corn flour from grains processed with alkaline cooking by use of peroxide value, UV and FTIR.

    PubMed

    Yahuaca-Juárez, B; Martínez-Flores, H E; Huerta-Ruelas, J A; Pless, R C; Vázquez-Landaverde, P A; Tello Santillán, R

    2013-03-01

    The objective of this work was to evaluate the effect of alkaline cooking on the oxidative stability of oil in corn flour. A central composite design was used to study the combined effect of lime concentration (%) and steep time (h) on peroxide value (PV); specific extinction coefficients at 232 and 270 nm (K232 and K270); and FTIR absorbance at 3009 cm(-1), 3444 cm(-1), and 3530 cm(-1) in oils from corn flour obtained by alkaline cooking. The results indicate that lime concentration and steep time affected the PV, K232, and K270. A decrease of 2.56 % was observed in the IR absorption bands, corresponding to the polyunsaturated fatty acids. The FTIR spectra also showed absorption bands related to the secondary oil oxidation products.

  18. Co-cultivation of Aspergillus nidulans Recombinant Strains Produces an Enzymatic Cocktail as Alternative to Alkaline Sugarcane Bagasse Pretreatment

    PubMed Central

    Lima, Matheus S.; Damasio, André R. de L.; Crnkovic, Paula M.; Pinto, Marcelo R.; da Silva, Ana M.; da Silva, Jean C. R.; Segato, Fernando; de Lucas, Rosymar C.; Jorge, João A.; Polizeli, Maria de L. T. de M.

    2016-01-01

    Plant materials represent a strategic energy source because they can give rise to sustainable biofuels through the fermentation of their carbohydrates. A clear example of a plant-derived biofuel resource is the sugar cane bagasse exhibiting 60–80% of fermentable sugars in its composition. However, the current methods of plant bioconversion employ severe and harmful chemical/physical pretreatments raising biofuel cost production and environmental degradation. Replacing these methods with co-cultivated enzymatic cocktails is an alternative. Here we propose a pretreatment for sugarcane bagasse using a multi-enzymatic cocktail from the co-cultivation of four Aspergillus nidulans recombinant strains. The co-cultivation resulted in the simultaneous production of GH51 arabinofuranosidase (AbfA), GH11 endo-1,4-xylanase (XlnA), GH43 endo-1,5-arabinanase (AbnA) and GH12 xyloglucan specific endo-β-1,4-glucanase (XegA). This core set of recombinant enzymes was more efficient than the alternative alkaline method in maintaining the cellulose integrity and exposing this cellulose to the following saccharification process. Thermogravimetric and differential thermal analysis revealed residual byproducts on the alkali pretreated biomass, which were not found in the enzymatic pretreatment. Therefore, the enzymatic pretreatment was residue-free and seemed to be more efficient than the applied alkaline method, which makes it suitable for bioethanol production. PMID:27199917

  19. Evaluation of electricity production from alkaline pretreated sludge using two-chamber microbial fuel cell.

    PubMed

    Xiao, Benyi; Yang, Fang; Liu, Junxin

    2013-06-15

    Electricity production from alkaline pretreated sludge was evaluated using a two-chamber microbial fuel cell (MFC). The electricity production was found to be stable over a long period of time (approximately 17 d) with voltage outputs and power densities of 0.47-0.52 V and 46.80-55.88 mW/m(2), respectively. The anode resistance was the main internal resistance (73.2%) of MFC in the stable stage. Most soluble organic matters (proteins and carbohydrates) in the anode chamber were first degraded and converted into volatile fatty acids (0-15 d), which were then degraded and converted into electricity and methane (15-29 d). The insoluble organics were solubilized thereby decreasing the sludge concentration and reducing the sludge mass. Methane was produced in the anode chamber owing to the growth of methanogens, which did not obviously affect the electricity production. The change in humic-like substances displayed a positive correlation with the electricity production of the MFC. Microbial analysis showed that methanogens and electricity-producing bacteria co-existed mostly on the surface as well as inside the anode. Decreasing the anode resistance and increasing the anode utilization could enhance the electricity production.

  20. Optimizing Phosphoric Acid plus Hydrogen Peroxide (PHP) Pretreatment on Wheat Straw by Response Surface Method for Enzymatic Saccharification.

    PubMed

    Qiu, Jingwen; Wang, Qing; Shen, Fei; Yang, Gang; Zhang, Yanzong; Deng, Shihuai; Zhang, Jing; Zeng, Yongmei; Song, Chun

    2017-03-01

    Wheat straw was pretreated by phosphoric acid plus hydrogen peroxide (PHP), in which temperature, time, and H3PO4 proportion for pretreatment were investigated by using response surface method. Results indicated that hemicellulose and lignin removal positively responded to the increase of pretreatment temperature, H3PO4 proportion, and time. H3PO4 proportion was the most important variable to control cellulose recovery, followed by pretreatment temperature and time. Moreover, these three variables all negatively related to cellulose recovery. Increasing H3PO4 proportion can improve enzymatic hydrolysis; however, reduction on cellulose recovery results in decrease of glucose yield. Extra high temperature or long time for pretreatment was not beneficial to enzymatic hydrolysis and glucose yield. Based on the criterion for minimizing H3PO4 usage and maximizing glucose yield, the optimized pretreatment conditions was 40 °C, 2.0 h, and H3PO4 proportion of 70.2 % (H2O2 proportion of 5.2 %), by which glucose yielded 299 mg/g wheat straw (946.2 mg/g cellulose) after 72-h enzymatic hydrolysis.

  1. Pre-treatment serum lactate dehydrogenase and alkaline phosphatase as predictors of metastases in extremity osteosarcoma

    PubMed Central

    Marais, Leonard C.; Bertie, Julia; Rodseth, Reitze; Sartorius, Benn; Ferreira, Nando

    2015-01-01

    Background The prognosis of patients with metastatic osteosarcoma remains poor. However, the chance of survival can be improved by surgical resection of all metastases. In this study we investigate the value of serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in predicting the presence of metastatic disease at time of diagnosis. Methods Sixty-one patients with histologically confirmed conventional osteosarcoma of the extremity were included in the study. Only 19.7% of cases presented without evidence of systemic spread of the disease. Pre-treatment serum ALP and LDH were analysed in patients with and without skeletal or pulmonary metastases. Results Serum LDH and ALP levels were not significantly different in patients with or without pulmonary metastases (p=0.88 and p=0.47, respectively). The serum LDH and ALP levels did however differ significantly in patients with or without skeletal metastases (p<0.001 and p=0.02, respectively). The optimal breakpoint for serum LDH as a marker of skeletal metastases was 849 IU/L (AUC 0.839; Sensitivity=0.88; Specificity=0.73). LDH >454 IU/L equated to 100% sensitivity for detected bone metastases (positive diagnostic likelihood ratio (DLR)=1.32). With a cut-off of 76 IU/L a sensitivity of 100% was reached for serum ALP predicting the presence of skeletal metastases (positive DLR=1.1). In a multivariate analysis both LDH ≥850 IU/L (odds ratio [OR]=9; 95% confidence interval (CI) 1.8–44.3) and ALP ≥280 IU/L (OR=10.3; 95% CI 2.1–50.5) were predictive of skeletal metastases. LDH however lost its significance in a multivariate model which included pre-treatment tumour volume. Conclusion In cases of osteosarcoma with LDH >850 IU/L and/or ALP >280 IU/L it may be prudent to consider more sensitive staging investigations for detection of skeletal metastases. Further research is required to determine the value and the most sensitive cut-off points of serum ALP and LDH in the prediction of skeletal metastases. PMID

  2. Effects of alkaline pretreatments and acid extraction conditions on the acid-soluble collagen from grass carp (Ctenopharyngodon idella) skin.

    PubMed

    Liu, Dasong; Wei, Guanmian; Li, Tiancheng; Hu, Jinhua; Lu, Naiyan; Regenstein, Joe M; Zhou, Peng

    2015-04-01

    This study investigated the effects of alkaline pretreatments and acid extraction conditions on the production of acid-soluble collagen (ASC) from grass carp skin. For alkaline pretreatment, 0.05 and 0.1M NaOH removed non-collagenous proteins without significant loss of ASC at 4, 10, 15 and 20 °C; while 0.2 and 0.5M NaOH caused significant loss of ASC, and 0.5M NaOH caused structural modification of ASC at 15 and 20 °C. For acid extraction at 4, 10, 15 and 20 °C, ASC was partly extracted by 0.1 and 0.2M acetic acid, while 0.5 and 1.0M acetic acid resulted in almost complete extraction. The processing conditions involving 0.05-0.1M NaOH for pretreatment, 0.5M acetic acid for extraction and 4-20 °C for both pretreatment and extraction, produced ASC with the structural integrity being well maintained and hence were recommended to prepare ASC from grass carp skin in practical application.

  3. High-efficiency ethanol production from lignocellulosic residues pretreated with alkaline H/sub 2/O/sub 2/

    SciTech Connect

    Gould, J.M.; Freer, S.N.

    1984-06-01

    Pretreatment should be economic and should not utilize toxic reagents. In this study locally obtained residues were used - wheat straw, cornstalks, corn husks and kenaf -as substrates. The high efficiency of glucose production from alkaline H/sub 2/O/sub 2/ pretreated lignocellulosic residues made these materials excellent substrates for ethanol production by Saccharomyces cerevisiae in combined saccharification/fermentation experiments. Results showed that overall efficiency of ethanol formation was 90% for pretreated corn cobs, stalks and husks compared to 50% for untreated materials. Yields from kenaf and oak were also enhanced although below the theoretical maximum. The lignin containing supernatant does not appear to be inhibitory to Saccharomyces cerevisiae growth or ethanol production. The improvement in conversion efficiency is apparently the result of the removal of about one half of the lignin along with an apparent reduction in the degree of crystallinity within the cellulose structure itself. 16 references.

  4. 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.

  5. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide.

    PubMed

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J

    2012-01-01

    In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H(2)O(2)) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175°C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115°C and 145°C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175°C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP) was more pronounced for SWA20 at 145°C, with a 26% increase in biogas production after 8days of digestion, compared to the control. When considering the increased substrate availability in the liquid fraction after MW pretreatment, a 78% improvement in biogas production vs. the control was achieved. Combining MW and H(2)O(2) modalities did not have a positive impact on OFMSW stabilization and enhanced biogas production. In general, all samples pretreated with H(2)O(2) displayed a long lag phase and the CBP was usually lower than MW irradiated only samples. First order rate constant was calculated.

  6. Sewage sludge pretreatment by microwave irradiation combined with activated carbon fibre at alkaline pH for anaerobic digestion.

    PubMed

    Sun, Dedong; Guo, Sixiao; Ma, Nina; Wang, Guowen; Ma, Chun; Hao, Jun; Xue, Mang; Zhang, Xinxin

    2016-01-01

    This research focuses on the effects of microwave-assisted activated carbon fibre (ACF) (MW-ACF) treatment on sewage sludge at alkaline pH. The disintegration and biodegradability of sewage sludge were studied. It was found that the MW-ACF process at alkaline pH provided a rapid and efficient process to disrupt the microbial cells in the sludge. The results suggested that when irradiated at 800 W MW for 110 s with a dose of 1.0 g ACF/g solid concentration (SS) at pH 10.5, the MW-ACF pretreatment achieved 55% SS disintegration, 23% greater than the value of MW alone (32%). The concentration of total nitrogen, total phosphorus, supernatant soluble chemical oxygen demand, protein, and polysaccharide increased by 60%, 144%, 145%, 74%, and 77%, respectively. An increase in biogas production by 63.7% was achieved after 20 days of anaerobic digestion (AD), compared to the control. The results indicated that the MW-ACF pretreatment process at alkaline pH provides novel sludge management options in disintegration of sewage sludge for further AD.

  7. Effect of thermal-alkaline pretreatment on the anaerobic digestion of streptomycin bacterial residues for methane production.

    PubMed

    Zhong, Weizhang; Li, Zaixing; Yang, Jingliang; Liu, Chun; Tian, Baokuo; Wang, Yongjun; Chen, Ping

    2014-01-01

    The anaerobic digestion of streptomycin bacterial residues, solutions with hazardous waste treatments and bioenergy recovery, was tested in laboratory-scale digesters at 35°C at various organic loading rates (OLRs). The methane production and biomass digestion were efficient at OLRs below 2.33 gVS L(-1) d(-1) but were deteriorated as OLR increased because of the increased total ammonia nitrogen (TAN) concentration from cell protein decay. The thermal-alkaline pretreatment with 0.10 NaOH/TS at 70°C for 2 h significantly improved the digestion performance. With the thermal-alkaline pretreatment, the volumetric reactor productivity and specific methane yield of the pretreated streptomycin bacterial residue increased by 22.08-27.08% compared with those of the unpretreated streptomycin bacterial residue at an OLR of 2.33 gVS L(-1) d(-1). The volatile solid removal was 64.09%, with less accumulation of TAN and total volatile fatty acid.

  8. Products of alkaline peroxide attack on wheat straw, oak, and keraf

    SciTech Connect

    Abbott, T.; Peterson, R.

    1985-07-01

    Wheat straw, oak, and kenaf were partially delignified by treatment with hydrogen peroxide at pH 11.0, and the water-soluble degradation products were characterized. Forty to sixty percent of the solubilized products were larger than 1000 molecular weight (MW), as determined by membrane ultrafiltration. Lignin degradation products in the low-molecular-weight fraction (is less than 1000) consisted primarily of aromatic and aliphatic carboxylic acids. 14 references.

  9. Microwave assisted alkaline pretreatment to enhance enzymatic saccharification of catalpa sawdust.

    PubMed

    Jin, Shuguang; Zhang, Guangming; Zhang, Panyue; Li, Fan; Wang, Siqi; Fan, Shiyang; Zhou, Shuqiong

    2016-12-01

    Catalpa sawdust, a promising biofuel production biomass, was pretreated by microwave-water, -NaOH, and -Ca(OH)2 to enhance enzymatic digestibility. After 48h enzymatic hydrolysis, microwave-Ca(OH)2 pretreated sample showed the highest reducing sugar yield. The content of hemicellulose and lignin in catalpa sawdust decreased after microwave-alkali pretreatment. SEM observation showed that the catalpa sawdust surface with microwave-Ca(OH)2 pretreatment suffered the most serious erosion. Crystallinity index of catalpa sawdust increased after all three kinds of pretreatment. The optimum conditions of microwave-Ca(OH)2 pretreatment were particle size of 40mesh, Ca(OH)2 dosage of 2.25% (w/v), microwave power of 400W, pretreatment time of 6min, enzyme loading of 175FPU/g, and hydrolysis time of 96h, and the reducing sugar yield of microwave-Ca(OH)2 pretreated catalpa sawdust reached 402.73mg/g, which increased by 682.15% compared with that of raw catalpa sawdust. The catalpa sawdust with microwave-Ca(OH)2 pretreatment is promising for biofuel production with great potential.

  10. Structures and stabilities of alkaline earth metal peroxides XO2 (X=Ca, Be, Mg) studied by a genetic algorithm

    SciTech Connect

    Zhao, Xin; Nguyen, Manh Cuong; Wang, Cai-Zhuang; Ho, Kai-Ming

    2013-09-17

    The structures and stabilities of alkaline earth metal peroxides XO2 (X = Ca, Be, Mg) were studied using an adaptive genetic algorithm (GA) for global structure optimization in combination with first-principles calculations. From the adaptive GA search, we obtained an orthorhombic structure for CaO2 with 12 atoms in the unit cell, which is energetically more favorable than the previously proposed structures. Reaction energy of the decomposition CaO2 → CaO + 1/2O2 determined by density functional theory (DFT) calculation shows that this orthorhombic calcium peroxide structure is thermodynamically stable. The simulated X-ray diffraction (XRD) pattern using our predicted structure is in excellent agreement with experimental data. We also show that crystal phase BeO2 is unlikely to exist under normal conditions. MgO2 has a cubic pyrite structure, but it is not stable against decomposition: MgO2 → MgO + 1/2O2.

  11. Relation of fatty acid composition in lead-exposed mallards to fat mobilization, lipid peroxidation and alkaline phosphatase activity

    USGS Publications Warehouse

    Mateo, R.; Beyer, W.N.; Spann, J.W.; Hoffman, D.J.

    2003-01-01

    The increase of n-6 polyunsaturated fatty acids (PUFA) in animal tissues has been proposed as a mechanism of Pb poisoning through lipid peroxidation or altered eicosanoids metabolism. We have studied fatty acid (FA) composition in liver and brain of mallards (Anas platyrhynchos) feeding for three weeks on diets containing combinations of low or high levels of vitamin E (20 or 200 UI/kg) and Pb (0 or 2 g/kg). Saturated FA, n-6 PUFA and total concentrations of FA were higher in livers of Pb-exposed mallards, but not in their brains. The percentage of n-6 PUFA in liver and brain was slightly higher in Pb-exposed mallards. The increase of n-6 PUFA in liver was associated with increased triglycerides and cholesterol in plasma, thus could be in part attributed to feed refusal and fat mobilization. The hepatic ratios between adrenic acid (22:4 n-6) and arachidonic acid (20:4 n-6) or between adrenic acid and linoleic acid (18:2 n-6) were higher in Pb exposed birds, supporting the existing hypothesis of increased fatty acid elongation by Pb. Among the possible consequences of increased n-6 PUFA concentration in tissues, we found increased lipid peroxidation in liver without important histopathological changes, and decreased plasma alkaline phosphatase activity that may reflect altered bone metabolism in birds.

  12. 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.

  13. A fuel-cell reactor for the direct synthesis of hydrogen peroxide alkaline solutions from H(2) and O(2).

    PubMed

    Yamanaka, Ichiro; Onisawa, Takeshi; Hashimoto, Toshikazu; Murayama, Toru

    2011-04-18

    The effects of the type of fuel-cell reactors (undivided or divided by cation- and anion-exchange membranes), alkaline electrolytes (LiOH, NaOH, KOH), vapor-grown carbon fiber (VGCF) cathode components (additives: none, activated carbon, Valcan XC72, Black Pearls 2000, Seast-6, and Ketjen Black), and the flow rates of anolyte (0, 1.5, 12 mL h(-1)) and catholyte (0, 12 mL h(-1)) on the formation of hydrogen peroxide were studied. A divided fuel-cell system, O(2) (g)|VGCF-XC72 cathode|2 M NaOH catholyte|cation-exchange membrane (Nafion-117)|Pt/XC72-VGCF anode|2 M NaOH anolyte at 12 mL h(-1) flow|H(2) (g), was effective for the selective formation of hydrogen peroxide, with 130 mA cm(-2) , a 2 M aqueous solution of H(2)O(2)/NaOH, and a current efficiency of 95 % at atmospheric pressure and 298 K. The current and formation rate gradually decreased over a long period of time. The cause of the slow decrease in electrocatalytic performance was revealed and the decrease was stopped by a flow of catholyte. Cyclic voltammetry studies at the VGCF-XC72 electrode indicated that fast diffusion of O(2) from the gas phase to the electrode, and quick desorption of hydrogen peroxide from the electrode to the electrolyte were essential for the efficient formation of solutions of H(2)O(2)/NaOH.

  14. Hydrothermal and alkaline hydrothermal pretreatments plus anaerobic digestion of sewage sludge for dewatering and biogas production: Bench-scale research and pilot-scale verification.

    PubMed

    Li, Chunxing; Wang, Xingdong; Zhang, Guangyi; Yu, Guangwei; Lin, Jingjiang; Wang, Yin

    2017-03-25

    To test the feasibility and practicability of the process combing hydrothermal pretreatment for dewatering with biogas production for full utilization of sewage sludge, hydrothermal/alkaline hydrothermal pretreatments and in turn anaerobic digestion of the filtrates obtained after dewatering the pretreated sludge were performed at bench- and pilot-scales. The hydrothermal temperature fell within the range of 140 °C-220 °C and the pretreatment time varied from 30 min to 120 min. For the alkaline hydrothermal pretreatment the pH value of the sludge was adjusted to 9.0-11.0 by adding Ca(OH)2. The results showed that the dewaterability of the sewage sludge was improved with increasing pretreatment temperature but the impact of the pretreatment time was not significant. The addition of Ca(OH)2 gave better performance on the subsequent mechanical dewatering of the pretreated sludge compared to pure hydrothermal pretreatment, and the higher the pH value was, the better the dewaterability of the pretreated sludge was. The conditions of 180 °C/30 min and 160 °C/60 min/pH = 10.0 (for hydrothermal and alkaline hydrothermal pretreatments, respectively) resulted in relatively good results in the theoretical energy balance, which were verified in the pilot-scale tests. Based on the data from the pilot tests, the alkaline hydrothermal process realized self-sufficiency in energy at the cost of a proper amount of CaO.

  15. Mass balance of pilot-scale pretreatment of sugarcane bagasse by steam explosion followed by alkaline delignification.

    PubMed

    Rocha, George J M; Martín, Carlos; da Silva, Vinícius F N; Gómez, Edgardo O; Gonçalves, Adilson R

    2012-05-01

    Five pilot-scale steam explosion pretreatments of sugarcane bagasse followed by alkaline delignification were explored. The solubilised lignin was precipitated with 98% sulphuric acid. Most of the pentosan (82.6%), and the acetyl group fractions were solubilised during pretreatment, while 90.2% of cellulose and 87.0% lignin were recovered in the solid fraction. Approximately 91% of the lignin and 72.5% of the pentosans contained in the steam-exploded solids were solubilised by delignification, resulting in a pulp with almost 90% of cellulose. The acidification of the black liquors allowed recovery of 48.3% of the lignin contained in the raw material. Around 14% of lignin, 22% of cellulose and 26% of pentosans were lost during the process. In order to increase material recovery, major changes, such as introduction of efficient condensers and the reduction in the number of washing steps, should be done in the process setup.

  16. Mechanistic study on ultrasound assisted pretreatment of sugarcane bagasse using metal salt with hydrogen peroxide for bioethanol production.

    PubMed

    Ramadoss, Govindarajan; Muthukumar, Karuppan

    2016-01-01

    This study presents the ultrasound assisted pretreatment of sugarcane bagasse (SCB) using metal salt with hydrogen peroxide for bioethanol production. Among the different metal salts used, maximum holocellulose recovery and delignification were achieved with ultrasound assisted titanium dioxide (TiO2) pretreatment (UATP) system. At optimum conditions (1% H2O2, 4 g SCB dosage, 60 min sonication time, 2:100 M ratio of metal salt and H2O2, 75°C, 50% ultrasound amplitude and 70% ultrasound duty cycle), 94.98 ± 1.11% holocellulose recovery and 78.72 ± 0.86% delignification were observed. The pretreated SCB was subjected to dilute acid hydrolysis using 0.25% H2SO4 and maximum xylose, glucose and arabinose concentration obtained were 10.94 ± 0.35 g/L, 14.86 ± 0.12 g/L and 2.52 ± 0.27 g/L, respectively. The inhibitors production was found to be very less (0.93 ± 0.11 g/L furfural and 0.76 ± 0.62 g/L acetic acid) and the maximum theoretical yield of glucose and hemicellulose conversion attained were 85.8% and 77%, respectively. The fermentation was carried out using Saccharomyces cerevisiae and at the end of 72 h, 0.468 g bioethanol/g holocellulose was achieved. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis of pretreated SCB was made and its morphology was studied using scanning electron microscopy (SEM). The compounds formed during the pretreatment were identified using gas chromatography-mass spectrometry (GC-MS) analysis.

  17. Anaerobic digestion of organic fraction of municipal solid waste combining two pretreatment modalities, high temperature microwave and hydrogen peroxide

    SciTech Connect

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin J.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Microwave and H{sub 2}O{sub 2} pretreatment were studied to enhance anaerobic digestion of organic waste. Black-Right-Pointing-Pointer The whole waste pretreated at 115 Degree-Sign C or 145 Degree-Sign C had the highest biogas production. Black-Right-Pointing-Pointer Biogas production of the whole waste decreased at 175 Degree-Sign C due to formation of refractory compounds. Black-Right-Pointing-Pointer Pretreatment to 145 Degree-Sign C and 175 Degree-Sign C were the best when considering only the free liquid fraction. Black-Right-Pointing-Pointer H{sub 2}O{sub 2} pretreatment had a lag phase and the biogas production was not higher than MW pretreated samples. - Abstract: In order to enhance anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW), pretreatment combining two modalities, microwave (MW) heating in presence or absence of hydrogen peroxide (H{sub 2}O{sub 2}) were investigated. The main pretreatment variables affecting the characteristics of the OFMSW were temperature (T) via MW irradiation and supplemental water additions of 20% and 30% (SWA20 and SW30). Subsequently, the focus of this study was to evaluate mesophilic batch AD performance in terms of biogas production, as well as changes in the characteristics of the OFMSW post digestion. A high MW induced temperature range (115-175 Degree-Sign C) was applied, using sealed vessels and a bench scale MW unit equipped with temperature and pressure controls. Biochemical methane potential (BMP) tests were conducted on the whole OFMSW as well as the liquid fractions. The whole OFMSW pretreated at 115 Degree-Sign C and 145 Degree-Sign C showed 4-7% improvement in biogas production over untreated OFMSW (control). When pretreated at 175 Degree-Sign C, biogas production decreased due to formation of refractory compounds, inhibiting the digestion. For the liquid fraction of OFMSW, the effect of pretreatment on the cumulative biogas production (CBP

  18. Pretreatment of whole blood using hydrogen peroxide and UV irradiation. Design of the advanced oxidation process.

    PubMed

    Bragg, Stefanie A; Armstrong, Kristie C; Xue, Zi-Ling

    2012-08-15

    A new process to pretreat blood samples has been developed. This process combines the Advanced Oxidation Process (AOP) treatment (using H(2)O(2) and UV irradiation) with acid deactivation of the enzyme catalase in blood. A four-cell reactor has been designed and built in house. The effect of pH on the AOP process has been investigated. The kinetics of the pretreatment process shows that at high C(H(2)O(2),t=0), the reaction is zeroth order with respect to C(H(2)O(2)) and first order with respect to C(blood). The rate limiting process is photon flux from the UV lamp. Degradation of whole blood has been compared with that of pure hemoglobin samples. The AOP pretreatment of the blood samples has led to the subsequent determination of chromium and zinc concentrations in the samples using electrochemical methods.

  19. Green coconut mesocarp pretreated by an alkaline process as raw material for bioethanol production.

    PubMed

    Soares, Jimmy; Demeke, Mekonnen M; Foulquié-Moreno, Maria R; Van de Velde, Miet; Verplaetse, Alex; Fernandes, Antonio Alberto Ribeiro; Thevelein, Johan M; Fernandes, Patricia Machado Bueno

    2016-09-01

    Cocos nucifera L., coconut, is a palm of high importance in the food industry, but a considerable part of the biomass is inedible. In this study, the pretreatment and saccharification parameters NaOH solution, pretreatment duration and enzyme load were evaluated for the production of hydrolysates from green coconut mesocarp using 18% (w/v) total solids (TS). Hydrolysates were not detoxified in order to preserve sugars solubilized during the pretreatment. Reduction of enzyme load from 15 to 7.5 filter paper cellulase unit (FPU)/g of biomass has little effect on the final ethanol titer. With optimized pretreatment and saccharification, hydrolysates with more than 7% (w/v) sugars were produced in 48h. Fermentation of the hydrolysate using industrial Saccharomyces cerevisiae strains produced 3.73% (v/v) ethanol. Our results showed a simple pretreatment condition with a high-solid load of biomass followed by saccharification and fermentation of undetoxified coconut mesocarp hydrolysates to produce ethanol with high titer.

  20. Alkaline Pretreatment of Sugarcane Bagasse and Filter Mud Codigested to Improve Biomethane Production

    PubMed Central

    Mehryar, Esmaeil; Bi, Jinhua

    2016-01-01

    To enhance the codigestion of degradation and improve biomethane production potential, sugarcane bagasse and filter mud were pretreated by sodium hydroxide NaOH 1 N at 100°C for 15, 30, and 45 minutes, respectively. Biomethane generation from 1-liter batch reactor was studied at mesophilic temperature (37 ± 1)°C, solid concentrations of 6%, and five levels of mixing proportion with and without pretreatment. The results demonstrate that codigestion of filter mud with bagasse produces more biomethane than fermentation of filter mud as single substrate; even codigested substrate composition presented a better balance of nutrients (C/N ratio of 24.70) when codigestion ratio between filter mud and bagasse was 25 : 75 in comparison to filter mud as single substrate (C/N ratio 9.68). All the pretreatments tested led to solubilization of the organic matter, with a maximum lignin reduction of 86.27% and cumulative yield of biomethane (195.8 mL·gVS−1, digestion of pretreated bagasse as single substrate) obtained after 45 minutes of cooking by NaOH 1 N at 100°C. Under this pretreatment condition, significant increase in cumulative methane yield was observed (126.2 mL·gVS−1) at codigestion ratio of 25 : 75 between filter mud and bagasse by increase of 81.20% from untreated composition. PMID:27738635

  1. Alkaline Pretreatment of Sugarcane Bagasse and Filter Mud Codigested to Improve Biomethane Production.

    PubMed

    Talha, Zahir; Ding, Weimin; Mehryar, Esmaeil; Hassan, Muhammad; Bi, Jinhua

    2016-01-01

    To enhance the codigestion of degradation and improve biomethane production potential, sugarcane bagasse and filter mud were pretreated by sodium hydroxide NaOH 1 N at 100°C for 15, 30, and 45 minutes, respectively. Biomethane generation from 1-liter batch reactor was studied at mesophilic temperature (37 ± 1)°C, solid concentrations of 6%, and five levels of mixing proportion with and without pretreatment. The results demonstrate that codigestion of filter mud with bagasse produces more biomethane than fermentation of filter mud as single substrate; even codigested substrate composition presented a better balance of nutrients (C/N ratio of 24.70) when codigestion ratio between filter mud and bagasse was 25 : 75 in comparison to filter mud as single substrate (C/N ratio 9.68). All the pretreatments tested led to solubilization of the organic matter, with a maximum lignin reduction of 86.27% and cumulative yield of biomethane (195.8 mL·gVS(-1), digestion of pretreated bagasse as single substrate) obtained after 45 minutes of cooking by NaOH 1 N at 100°C. Under this pretreatment condition, significant increase in cumulative methane yield was observed (126.2 mL·gVS(-1)) at codigestion ratio of 25 : 75 between filter mud and bagasse by increase of 81.20% from untreated composition.

  2. Optimization of the Alkaline Pretreatment of Rice Straw for Enhanced Methane Yield

    PubMed Central

    Song, Zilin; Yang, Gaihe; Han, Xinhui; Feng, Yongzhong; Ren, Guangxin

    2013-01-01

    The lime pretreatment process for rice straw was optimized to enhance the biodegradation performance and increase biogas yield. The optimization was implemented using response surface methodology (RSM) and Box-Behnken experimental design. The effects of biodegradation, as well as the interactive effects of Ca(OH)2 concentration, pretreatment time, and inoculum amount on biogas improvement, were investigated. Rice straw compounds, such as lignin, cellulose, and hemicellulose, were significantly degraded with increasing Ca(OH)2 concentration. The optimal conditions for the use of pretreated rice straw in anaerobic digestion were 9.81% Ca(OH)2 (w/w TS), 5.89 d treatment time, and 45.12% inoculum content, which resulted in a methane yield of 225.3 mL/g VS. A determination coefficient (R2) of 96% was obtained, indicating that the model used to predict the anabolic digestion process shows a favorable fit with the experimental parameters. PMID:23509824

  3. 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.

  4. 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.

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

    DOE PAGES

    Meng, Xianzhi; Wells, Tyrone; Sun, Qining; ...

    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

  6. Characteristics and Gel Properties of Gelatin from Goat Skin as Influenced by Alkaline-pretreatment Conditions

    PubMed Central

    Mad-Ali, Sulaiman; Benjakul, Soottawat; Prodpran, Thummanoon; Maqsood, Sajid

    2016-01-01

    Characteristics and properties of gelatin from goat skin pretreated with NaOH solutions (0.50 and 0.75 M) for various times (1 to 4 days) were investigated. All gelatins contained α-chains as the predominant component, followed by β-chain. Gelling and melting temperatures of those gelatins were 23.02°C to 24.16°C and 33.07°C to 34.51°C, respectively. Gel strength of gelatins increased as NaOH concentration and pretreatment time increased (p<0.05). Pretreatment for a longer time yielded gelatin with a decrease in L*-value but an increase in b*-value. Pretreatment of goat skin using 0.75 M NaOH for 2 days rendered the highest yield (15.95%, wet weight basis) as well as high gel strength (222.42 g), which was higher than bovine gelatin (199.15 g). Gelatin obtained had the imino acid content of 226 residues/1,000 residues and the gelatin gel had a fine and ordered structure. Therefore, goat skin gelatin could be used as a potential replacer of commercial gelatin. PMID:26954127

  7. Effects of ozone and ozone/peroxide pretreatments on disinfection byproduct formation during subsequent chlorination and chloramination.

    PubMed

    Yang, Xin; Peng, Jinfeng; Chen, Baiyang; Guo, Wanhong; Liang, Yongmei; Liu, Wei; Liu, Lu

    2012-11-15

    Ozone (O3) and ozone/hydrogen peroxide (O3/H2O2) can be used in water treatment facilities to remove many organic micropollutants with taste, odor, and color implications. The effects of O3 and O3/H2O2 on the formation of disinfection byproducts (DBPs) in subsequent chlorination and chloramination processes, however, are not well determined. In this study, we compared the yields of a series of regulated and emerging DBPs during sequenced O3-Cl2, O3/H2O2-Cl2, O3-NH2Cl, and O3/H2O2-NH2Cl oxidation of 11 samples, each with different hydrophobicity, bromide concentration, soluble microbial products, and humic substances. For most water, pretreatment with O3 and O3/H2O2 increased the formation of chloral hydrate (CH), trichloronitromethane (TCNM) and haloketones (HKs) but lowered the yields of haloacetonitriles (HANs) during chlorination processes. Compared with O3 alone, O3/H2O2 in combination generated more CH and HKs during chlorination, and their extents of formation appeared to depend on the O3 doses. In terms of chloramination, both O3 and O3/H2O2 reduced THM, HAA, and HAN formation significantly without increasing CH, TCNM, or HKs. These results suggest that O3 or O3/H2O2 pretreatments may provide some benefits for the chloramination process in controlling regulated and emerging DBPs in waters without high bromide content.

  8. Enhancement of enzymatic hydrolysis of wheat straw by gamma irradiation-alkaline pretreatment

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-06-01

    Pretreatment of wheat straw with gamma irradiation and NaOH was performed to enhance the enzymatic hydrolysis of wheat straw for production of reducing sugar. The results showed that the irradiation of wheat straw at 50 kGy decreased the yield of reducing sugar, however, the reducing sugar yield increased with increasing dose from 50 kGy to 400 kGy. The irradiation of wheat straw at 100 kGy can significantly decrease NaOH consumption and treatment time. The reducing sugar yield could reach 72.67% after irradiation at 100 kGy and 2% NaOH treatment for 1 h. The combined pretreatment of wheat straw by gamma radiation and NaOH immersion can increase the solubilization of hemicellulose and lignin as well as the accessible surface area for enzyme molecules.

  9. Alkaline pretreatment improves saccharification and ethanol yield from waste money bills.

    PubMed

    Sheikh, Md Mominul Islam; Kim, Chul-Hwan; Park, Hyeon-Jin; Kim, Sung-Ho; Kim, Gyeong-Chul; Lee, Ji-Young; Sim, Sung-Woong; Kim, Jae Won

    2013-01-01

    Waste money bills (WMB) is a by-product of the money making process that consists of rich-cellulosic material for many biotechnological applications. This waste money bills is unusable and usually exhausted. Saccharification was improved using various concentrations of sodium hydroxide, NaOH (0.0, 0.5, 1.0, 2.0, 2.5, and 3.0% v/v) and various reaction times (20, 30, and 40 min) during pretreatment at 121 °C. Prior to ethanol fermentation, the highest glucose yield (62.2 mg/mL) was found by pretreatment consisting of 30 min at 2.0% NaOH, and it increased 33.8% as compared to an untreated sample. The highest amount of ethanol was obtained (26.1 mg/mL) during fermentation, and this was increased 95.3 and 22.5% as compared to aerobic and anaerobic conditions respectively during pretreatment with 2.0% NaOH for 30 min. Under anaerobic conditions, ethanol fermentation was enhanced by adding 0.4 mmol benzoic acid. Production of ethanol from waste money bills would cut waste management costs and make profitable.

  10. Effect of hydrothermal pretreatment on the structural changes of alkaline ethanol lignin from wheat straw

    PubMed Central

    Chen, Xue; Li, Hanyin; Sun, Shaoni; Cao, Xuefei; Sun, Runcang

    2016-01-01

    Due to the enormous abundance of lignin and its unique aromatic nature, lignin has great potential for the production of industrially useful fuels, chemicals, and materials. However, the rigid and compact structure of the plant cell walls significantly blocks the separation of lignin. In this study, wheat straw was hydrothermally pretreated at different temperatures (120–200 °C) followed by post-treatment with 70% ethanol containing 1% NaOH to improve the isolation of lignin. Results demonstrated that the content of associated carbohydrates of the lignin fractions was gradually reduced with the increment of the hydrothermal severity. The structure of the lignins changed regularly with the increase of the pretreatment temperature from 120 to 200 °C. In particular, the contents of β-O-4′, β-β′, β-5′ linkages and aliphatic OH in the lignins showed a tendency of decrease, while the content of phenolic OH and thermal stability of the lignin fractions increased steadily as the increment of the pretreatment temperature. PMID:27982101

  11. Effect of hydrothermal pretreatment on the structural changes of alkaline ethanol lignin from wheat straw

    NASA Astrophysics Data System (ADS)

    Chen, Xue; Li, Hanyin; Sun, Shaoni; Cao, Xuefei; Sun, Runcang

    2016-12-01

    Due to the enormous abundance of lignin and its unique aromatic nature, lignin has great potential for the production of industrially useful fuels, chemicals, and materials. However, the rigid and compact structure of the plant cell walls significantly blocks the separation of lignin. In this study, wheat straw was hydrothermally pretreated at different temperatures (120–200 °C) followed by post-treatment with 70% ethanol containing 1% NaOH to improve the isolation of lignin. Results demonstrated that the content of associated carbohydrates of the lignin fractions was gradually reduced with the increment of the hydrothermal severity. The structure of the lignins changed regularly with the increase of the pretreatment temperature from 120 to 200 °C. In particular, the contents of β-O-4‧, β-β‧, β-5‧ linkages and aliphatic OH in the lignins showed a tendency of decrease, while the content of phenolic OH and thermal stability of the lignin fractions increased steadily as the increment of the pretreatment temperature.

  12. 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

    2013-10-02

    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.

  13. Assessment of commercial hemicellulases for saccharification of alkaline pretreated perennial biomass.

    PubMed

    Sills, Deborah L; Gossett, James M

    2011-01-01

    The objective of this research was to measure the effects of different cellulase and hemicellulase mixtures on fermentable sugar production from two different perennial biomasses--switchgrass and a low-impact, high-diversity prairie biomass mixture (LIHD). Each was subjected to NaOH pretreatment, followed by hydrolysis with a commercial cellulase and β-glucosidase mixture [CB] supplemented with either of two hemicellulases. For both biomasses, there was little gain in sugar yield when using CB alone beyond 20-25 mg/g TS; further gain in yield was possible only through hemicellulase supplementation. An equation that modeled CB and hemicellulase effects as occurring independently fit the data reasonably well, except at the lowest of cellulase loadings with hemicellulase, where synergistic interactions were evident. Examination of the marginal effectiveness of enzyme loadings (incremental grams sugar per incremental mg enzyme) over a broad range of loadings suggests that there is no need to customize enzymatic hydrolysis for NaOH-pretreated switchgrass and LIHD.

  14. Improvement of anaerobic digestion of waste-activated sludge by using H₂O₂ oxidation, electrolysis, electro-oxidation and thermo-alkaline pretreatments.

    PubMed

    Feki, Emna; Khoufi, Sonia; Loukil, Slim; Sayadi, Sami

    2015-10-01

    Disintegration of municipal waste-activated sludge (WAS) is regarded as a prerequisite of the anaerobic digestion process to reduce sludge volume and improve biogas yield. Pretreatment of WAS using thermo-alkaline (TA), H2O2 oxidation, electrolysis and electro-oxidation (EO) processes were investigated and compared in term of COD solubilization and biogas production. For each pretreatment, the influences of different operational variables were studied in detail. At optimum conditions, EO gave the maximum COD solubilization (28 %). The effects of pretreatments under the optimum conditions on anaerobic digestion were experienced with biochemical methane potential assay. Significant increases in biogas yield up to 78 and 40 % were observed respectively in the EO and TA pretreated samples compared to raw sludge. Results clearly revealed that the application of EO is a significant alternative method for the improvement of WAS anaerobic digestion.

  15. Evaluation of alkaline pretreatment temperature on a multi-product basis for the co-production of glucose and hemicellulose based films from lignocellulosic biomass.

    PubMed

    Bahcegul, Erinc; Toraman, Hilal Ezgi; Ozkan, Necati; Bakir, Ufuk

    2012-01-01

    Cotton stalks were subjected to alkaline pretreatment for the co-production of glucose and hemicellulose based films with a multi-product approach. Three pretreatment temperatures (25, 60 and 90 °C) were evaluated for their effects both on the glucose yield and on the properties of hemicellulose based films. Compared to untreated cotton stalks, the glucose yields were enhanced 3.9, 4.1 and 4.2 times for pretreatments conducted at 25, 60 and 90 °C, respectively. The pretreatment temperature of 90 °C was detrimental in terms of film formation. Tensile energy to break values of the films obtained after pretreatments conducted at 25, 60 and 90 °C were 1.1, 0.8, and 0.4 MJ/m3, respectively. The hemicellulosic part of the process, which considers the production of hemicellulose based films, should govern the pretreatment temperature since it was more responsive to the changes in the pretreatment temperature compared to the cellulosic part that accounts for glucose production.

  16. 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

  17. 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.

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

    PubMed

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

    2015-11-13

    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.

  19. Alkaline-mechanical pretreatment process for enhanced anaerobic digestion of thickened waste activated sludge with a novel crushing device: Performance evaluation and economic analysis.

    PubMed

    Cho, Si-Kyung; Ju, Hyun-Jun; Lee, Jeong-Gyu; Kim, Sang-Hyoun

    2014-08-01

    Although various pretreatments have been widely investigated to enhance the anaerobic digestion (AD) of waste activated sludge (WAS), economic feasibility issues have limited real-world applications. The authors examined the performance and economic analysis of an alkaline-mechanical process with a novel mechanical crushing device for thickened WAS pretreatment. The pretreatment at 40gTS/L, pH 13, and 90min reaction time achieved 64% of solubilization efficiency and 8.3 times higher CH4 yield than the control. In addition, a synergistic CH4 yield enhancement was observed when the pretreated and raw WAS were used together as feedstock, and the greatest synergy was observed at a volumetric mixture ratio of 50:50. Economic estimates indicate that up to 22% of WAS treatment costs would be saved by the installation of the suggested process. The experimental results clearly indicate that the alkaline-mechanical process would be highly effective and economically feasible for the AD of thickened WAS.

  20. Pretreating lignocellulosic biomass by the concentrated phosphoric acid plus hydrogen peroxide (PHP) for enzymatic hydrolysis: evaluating the pretreatment flexibility on feedstocks and particle sizes.

    PubMed

    Wang, Qing; Wang, Zhanghong; Shen, Fei; Hu, Jinguang; Sun, Fubao; Lin, Lili; Yang, Gang; Zhang, Yanzong; Deng, Shihuai

    2014-08-01

    In order to seek a high-efficient pretreatment path for converting lignocellulosic feedstocks to fermentable sugars by enzymatic hydrolysis, the concentrated H₃PO₄ plus H₂O₂ (PHP) was attempted to pretreat different lignocellulosic biomass for evaluating the pretreatment flexibility on feedstocks. Meanwhile, the responses of pretreatment to particle sizes were also evaluated. When the PHP-pretreatment was employed (final H₂O₂ and H₃PO₄ concentration of 1.77% and 80.0%), 71-96% lignin and more than 95% hemicellulose in various feedstocks (agricultural residues, hardwood, softwood, bamboo, and their mixture, and garden wastes mixture) can be removed. Consequently, more than 90% glucose conversion was uniformly achieved indicating PHP greatly improved the pretreatment flexibility to different feedstocks. Moreover, when wheat straw and oak chips were PHP-pretreated with different sizes, the average glucose conversion reached 94.9% and 100% with lower coefficient of variation (7.9% and 0.0%), which implied PHP-pretreatment can significantly weaken the negative effects of feedstock sizes on subsequent conversion.

  1. Pretreatment Alkaline Phosphatase and Epstein-Barr Virus DNA Predict Poor Prognosis and Response to Salvage Radiotherapy in Patients with Nasopharyngeal Carcinoma and Metachronous Bone-Only Metastasis

    PubMed Central

    He, ShaSha; Wang, Yan; Peng, Hao; Yang, Lin; Chen, HaiYang; Liang, ShaoBo; Lu, LiXia; Chen, Yong

    2017-01-01

    Background: The bones are the most common site of distant metastasis in nasopharyngeal carcinoma (NPC). Few prognostic markers are available to guide treatment and sub-classify patients with bone metastasis. We aimed to identify the prognostic value of pretreatment serum alkaline phosphatase (ALP) and plasma Epstein-Barr virus DNA (EBV DNA) in patients with bone-only metastasis. Methods: A total of 272 patients who developed bone-only metastases after therapy were retrospectively analyzed. Patients were categorized according to pretreatment serum ALP (< or ≥ 110 U/L) and pretreatment plasma EBV DNA (< or ≥ 6,750 copies ml-1). Univariate and multivariate analyses of clinical variables were performed using Cox proportional hazards regression models. Overall survival (OS) was analyzed using the Kaplan-Meier method and compared using the log-rank test. Results: Median OS for the cohort was 34.06 months (range, 2.53-143.87 months). Multivariate Cox proportional hazard analysis verified pretreatment serum ALP and pretreatment plasma EBV DNA were independent prognostic factors for OS. In stratified survival analysis of patients with elevated pretreatment serum ALP and/or plasma EBV DNA, delivery of radiotherapy (RT) to bone metastases provided a significant OS benefit compared to other therapeutic methods (P < 0.05). Conclusions: This study demonstrates two important points: firstly, pretreatment serum ALP and plasma EBV DNA have prognostic value at the first diagnosis of bone-only metastasis in NPC. Secondly, radiotherapy of bone metastasis improves the prognosis of patients with elevated pretreatment serum ALP and plasma EBV DNA. PMID:28261343

  2. Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge.

    PubMed

    Zhao, Jianwei; Wang, Dongbo; Li, Xiaoming; Yang, Qi; Chen, Hongbo; Zhong, Yu; Zeng, Guangming

    2015-07-01

    Alkaline condition (especially pH 10) has been demonstrated to be a promising method for short-chain fatty acid (SCFA) production from waste activated sludge anaerobic fermentation, because it can effectively inhibit the activities of methanogens. However, due to the limit of sludge solubilization rate, long fermentation time is required but SCFA yield is still limited. This paper reports a new pretreatment method for alkaline fermentation, i.e., using free nitrous acid (FNA) to pretreat sludge for 2 d, by which the fermentation time is remarkably shortened and meanwhile the SCFA production is significantly enhanced. Experimental results showed the highest SCFA production of 370.1 mg COD/g VSS (volatile suspended solids) was achieved at 1.54 mg FNA/L pretreatment integration with 2 d of pH 10 fermentation, which was 4.7- and 1.5-fold of that in the blank (uncontrolled) and sole pH 10 systems, respectively. The total time of this integration system was only 4 d, whereas the corresponding time was 15 d in the blank and 8 d in the sole pH 10 systems. The mechanism study showed that compared with pH 10, FNA pretreatment accelerated disruption of both extracellular polymeric substances and cell envelope. After FNA pretreatment, pH 10 treatment (1 d) caused 38.0% higher substrate solubilization than the sole FNA, which indicated that FNA integration with pH 10 could cause positive synergy on sludge solubilization. It was also observed that this integration method benefited hydrolysis and acidification processes. Therefore, more SCFA was produced, but less fermentation time was required in the integrated system.

  3. Multi stage peroxide and activated peroxide bleaching of kenaf bast pulp.

    PubMed

    Zeinaly, Farhad; Shakhes, Jalal; Zeinali, Nooshin

    2013-02-15

    Soda-anthraquinone kenaf bast pulp (12.5 kappa number and 32% ISO brightness) has been bleached with multi stage peroxide bleaching process. Bleaching process was carried out in different sequences of peroxide stage without and with activator (tetraacetylethylenediamine, TAED) to about 80% ISO brightness. Full bleached pulp production with high brightness and viscosity and also, low chemical oxygen demand (COD) and no adsorbable organic halogens (AOX) in effluent are the aims of this study. The effects of temperature, retention time, chemical charges, TAED/peroxide ratio and alkalinity have been studied in order to maximize the brightness gain at the lowest viscosity loss. H(2)O(2) was activated as bleaching agent under milder conditions, such as low alkalinity or low temperature, by TAED activator. Therefore, TAED charge caused to an improvement in viscosity, pulp yield and effluent COD load. Pre-treatment with EDTA for 30 min and in acidic condition gave 2-4% gain in ISO brightness.

  4. Effect of hydrogen peroxide pretreatment on ZnO-based metal–semiconductor–metal ultraviolet photodetectors deposited using plasma-enhanced atomic layer deposition

    SciTech Connect

    Lin, Yu-Chang; Lee, Hsin-Ying; Lee, Tsung-Hsin

    2016-01-15

    In this study, zinc oxide (ZnO) films were deposited on sapphire substrates using a plasma-enhanced atomic layer deposition system. Prior to deposition, the substrates were treated with hydrogen peroxide (H{sub 2}O{sub 2}) in order to increase nucleation on the initial sapphire surface and, thus, enhance the quality of deposited ZnO films. Furthermore, x-ray diffraction spectroscopy measurements indicated that the crystallinity of ZnO films was considerably enhanced by H{sub 2}O{sub 2} pretreatment, with the strongest (002) diffraction peak occurring for the film pretreated with H{sub 2}O{sub 2} for 60 min. X-ray photoelectron spectroscopy also was used, and the results indicated that a high number of Zn–O bonds was generated in ZnO films pretreated appropriately with H{sub 2}O{sub 2}. The ZnO film deposited on a sapphire substrate with H{sub 2}O{sub 2} pretreatment for 60 min was applied to metal–semiconductor–metal ultraviolet photodetectors (MSM-UPDs) as an active layer. The fabricated ZnO MSM-UPDs showed improvements in dark current and ultraviolet–visible rejection ratios (0.27 μA and 1.06 × 10{sup 3}, respectively) compared to traditional devices.

  5. Effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement

    PubMed Central

    Shin, Tae-Bong; Lee, Joo-Hee; Ahn, Kang-Min; Kim, Tae-Hyung

    2016-01-01

    PURPOSE To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at 80℃ after hydrogen peroxide etching. After storage of the specimens in distilled water at 37℃ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (α=0.05). RESULTS Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P<.05). Heat drying after silanization also significantly increased the bond strength (Group 3 and 4) (P<.05). However, no effect was determined for hydrogen peroxide etching before applying silane agent (Group 2 and 3) (P>.05). CONCLUSION Fiber post silanization and subsequent heat treatment (80℃) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study. PMID:27141252

  6. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize (Zea mays L.) lines.

    PubMed

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D; Williams, Daniel L; Magee, Timothy D; Kaeppler, Shawn M; de Leon, Natalia; Hodge, David B

    2015-07-01

    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.

  7. 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

  8. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize ( Zea mays L.) lines

    SciTech Connect

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; Williams, Daniel L.; Magee, Timothy D.; Kaeppler, Shawn M.; de Leon, Natalia; Hodge, David B.

    2015-02-20

    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. Also, 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. In conclusion, 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

  9. 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...

  10. Asparagus stem as a new lignocellulosic biomass feedstock for anaerobic digestion: increasing hydrolysis rate, methane production and biodegradability by alkaline pretreatment.

    PubMed

    Chen, Xiaohua; Gu, Yu; Zhou, Xuefei; Zhang, Yalei

    2014-07-01

    Recently, anaerobic digestion of lignocellulosic biomass for methane production has attracted considerable attention. However, there is little information regarding methane production from asparagus stem, a typical lignocellulosic biomass, by anaerobic digestion. In this study, alkaline pretreatment of asparagus stem was investigated for its ability to increase hydrolysis rate and methane production and to improve biodegradability (BD). The hydrolysis rate increased with increasing NaOH dose, due to higher removal rates of lignin and hemicelluloses. However, the optimal NaOH dose was 6% (w/w) according to the specific methane production (SMP). Under this condition, the SMP and the technical digestion time of the NaOH-treated asparagus stem were 242.3 mL/g VS and 18 days, which were 38.4% higher and 51.4% shorter than those of the untreated sample, respectively. The BD was improved from 40.1% to 55.4%. These results indicate that alkaline pretreatment could be an efficient method for increasing methane production from asparagus stem.

  11. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize ( Zea mays L.) lines

    DOE PAGES

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; ...

    2015-02-20

    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)more » 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. Also, 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. In conclusion, 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« less

  12. Copper peroxide

    NASA Technical Reports Server (NTRS)

    Moser, L.

    1988-01-01

    A number of oxidizing agents, including chlorine, bromine, ozone and other peroxides, were allowed to act on copper solutions with the intention of forming copper peroxide. The only successful agent appears to be hydrogen peroxide. It must be used in a neutral 50 to 30 percent solution at a temperature near zero. Other methods described in the literature apparently do not work. The excess of hydrogen must be quickly sucked out of the brown precipitate, which it is best to wash with alcohol and ether. The product, crystalline under a microscope, can be analyzed only approximately. It approaches the formula CuO2H2O. In alkaline solution it appears to act catalytically in causing the decomposition of other peroxides, so that Na2O2 cannot be used to prepare it. On the addition of acids the H2O2 is regenerated. The dry substance decomposes much more slowly than the moist but is not very stable.

  13. Thermo-alkaline pretreatment of waste activated sludge at low-temperatures: effects on sludge disintegration, methane production, and methanogen community structure.

    PubMed

    Kim, Jaai; Yu, Youngseob; Lee, Changsoo

    2013-09-01

    Low-temperature thermo-alkaline pretreatment of waste activated sludge (WAS) was studied, within the region of 0-0.2 M NaOH and 60-90°C, for the effects of NaOH concentration and temperature on sludge degradability in anaerobic digestion (AD). Significant disintegration of sludge solids (up to 75.6%) and an increase in methane production (up to 70.6%) were observed in the pretreatment trials. Two quadratic models were successfully generated by response surface analysis (R(2)>0.9, p<0.05) to approximate how the degree of sludge disintegration (SD) and methane production (MP) respond to changes in the pretreatment conditions. The maximum responses of SD (77.8%) and MP (73.9% increase over the control) were shown at [0.16 M NaOH, 90°C] and [0.10 M NaOH, 73.7°C], respectively. NaOH addition showed a significant influence on the evolution of methanogen community structure during AD, whereas temperature did not. Aceticlastic Methanosaeta and Methanosarcina speceies were likely the major methanogens.

  14. Combined pretreatment using alkaline hydrothermal and ball milling to enhance enzymatic hydrolysis of oil palm mesocarp fiber.

    PubMed

    Zakaria, Mohd Rafein; Hirata, Satoshi; Hassan, Mohd Ali

    2014-10-01

    Hydrothermal pretreatment of oil palm mesocarp fiber was conducted in tube reactor at treatment severity ranges of log Ro = 3.66-4.83 and partial removal of hemicellulose with migration of lignin was obtained. Concerning maximal recovery of glucose and xylose, 1.5% NaOH was impregnated in the system and subsequent ball milling treatment was employed to improve the conversion yield. The effects of combined hydrothermal and ball milling pretreatments were evaluated by chemical composition changes by using FT-IR, WAXD and morphological alterations by SEM. The successful of pretreatments were assessed by the degree of enzymatic digestibility of treated samples. The highest xylose and glucose yields obtained were 63.2% and 97.3% respectively at cellulase loadings of 10 FPU/g-substrate which is the highest conversion from OPMF ever reported.

  15. Evaluation of electricity generation from ultrasonic and heat/alkaline pretreatment of different sludge types using microbial fuel cells.

    PubMed

    Oh, Sang-Eun; Yoon, Joung Yee; Gurung, Anup; Kim, Dong-Jin

    2014-08-01

    This study investigated the effects of different sludge pretreatment methods (ultrasonic vs. combined heat/alkali) with varied sources of municipal sewage sludge (primary sludge (PS), secondary excess sludge (ES), anaerobic digestion sludge (ADS)) on electricity generation in microbial fuel cells (MFCs). Introduction of ultrasonically pretreated sludge (PS, ES, ADS) to MFCs generated maximum power densities of 13.59, 9.78 and 12.67mW/m(2) and soluble COD (SCOD) removal efficiencies of 87%, 90% and 57%, respectively. The sludge pretreated by combined heat/alkali (0.04N NaOH at 120°C for 1h) produced maximum power densities of 10.03, 5.21 and 12.53mW/m(2) and SCOD removal efficiencies of 83%, 75% and 74% with PS, ES and ADS samples, respectively. Higher SCOD by sludge pretreatment enhanced performance of the MFCs and the electricity generation was linearly proportional to the SCOD removal, especially for ES.

  16. Improved bioconversion of poplar by synergistic treatments with white-rot fungus Trametes velutina D10149 pretreatment and alkaline fractionation.

    PubMed

    Yang, Haiyan; Wang, Kun; Wang, Wei; Sun, Run-Cang

    2013-02-01

    Successive treatments with fungus and alkali were proposed to reduce the recalcitrance and improved the enzymatic digestibility of triploid poplar. Biopretreatment with Trametes velutina D10149 for 0, 4, 8, 12 and 16weeks gradually degraded hemicelluloses and lignin, and improved the digestibility of cellulose from 4.0% to 19.5% with the increasing dry mass loss of lignocelluloses from 15.5% to 53.4%. Combining with alkaline fractionation, biopretreatment for 4weeks significantly enhanced the availability of cellulose and achieved a maximum glucose yield (38.8% of the original cellulose) with a dry mass loss of 24.4%. The BET surface area of lignocelluloses increased from 1.7 to 10.6m(2)/g after combination of 8weeks biopretreatment and alkaline fractionation. Moreover, alkaline fractionation removed amorphous and low molecular components, which incurred a higher crystalline index and narrower molecular weight distribution of residual carbohydrates in synergistically treated samples as compared to biopretreated samples.

  17. Hydrogen Peroxide Pretreatment Mitigates Cadmium-Induced Oxidative Stress in Brassica napus L.: An Intrinsic Study on Antioxidant Defense and Glyoxalase Systems

    PubMed Central

    Hasanuzzaman, Mirza; Nahar, Kamrun; Gill, Sarvajeet S.; Alharby, Hesham F.; Razafindrabe, Bam H. N.; Fujita, Masayuki

    2017-01-01

    Cadmium (Cd) is considered as one of the most toxic metals for plant growth and development. In the present study, we investigated the role of externally applied hydrogen peroxide (H2O2) in regulating the antioxidant defense and glyoxalase systems in conferring Cd-induced oxidative stress tolerance in rapeseed (Brassica napus L.). Seedlings were pretreated with 50 μM H2O2 for 24 h. These pretreated seedlings as well as non-pretreated seedlings were grown for another 48 h at two concentrations of CdCl2 (0.5 and 1.0 mM). Both the levels of Cd increased MDA and H2O2 levels and lipoxygenase activity while ascorbate (AsA) declined significantly. However, reduced glutathione (GSH) content showed an increase at 0.5 mM CdCl2, but glutathione disulfide (GSSG) increased at any level of Cd with a decrease in GSH/GSSG ratio. The activities of ascorbate peroxidase (APX) and glutathione S-transferase (GST) upregulated due to Cd treatment in dose-dependent manners, while glutathione reductase (GR) and glutathione peroxidase (GPX) increased only at 0.5 mM CdCl2 and decreased at higher dose. The activity of monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), catalase (CAT), glyoxalase I (Gly I), and glyoxalase II (Gly II) decreased under Cd stress. On the other hand, H2O2 pretreated seedlings, when exposed to Cd, AsA and GSH contents and GSH/GSSG ratio increased noticeably. H2O2 pretreatment increased the activities of APX, MDHAR, DHAR, GR, GST, GPX, and CAT of Cd affected seedlings. Thus enhancement of both the non-enzymatic and enzymatic antioxidants helped to decrease the oxidative damage as indicated by decreased levels of H2O2 and MDA. The seedlings which were pretreated with H2O2 also showed enhanced glyoxalase system. The activities of Gly I, and Gly II and the content of GSH increased significantly due to H2O2 pretreatment in Cd affected seedlings, compared to the Cd-stressed plants without H2O2 pretreatment which were vital for methylglyoxal

  18. Effect of dilute alkaline pretreatment on the conversion of different parts of corn stalk to fermentable sugars and its application in acetone-butanol-ethanol fermentation.

    PubMed

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

    2016-07-01

    To investigate the effect of dilute alkaline pretreatment on different parts of biomass, corn stalk was separated into flower, leaf, cob, husk and stem, which were treated by NaOH in range of temperature and chemical loading. The NaOH-pretreated solid was then enzymatic hydrolysis and used as the substrate for batch acetone-butanol-ethanol (ABE) fermentation. The results demonstrated the five parts of corn stalk could be used as potential feedstock separately, with vivid performances in solvents production. Under the optimized conditions towards high product titer, 7.5g/L, 7.6g/L, 9.4g/L, 7g/L and 7.6g/L of butanol was obtained in the fermentation broth of flower, leaf, cob, husk and stem hydrolysate, respectively. Under the optimized conditions towards high product yield, 143.7g/kg, 126.3g/kg, 169.1g/kg, 107.7g/kg and 116.4g/kg of ABE solvent were generated, respectively.

  19. Extraction and characterization of gelatin from the feet of Pekin duck (Anas platyrhynchos domestica) as affected by acid, alkaline, and enzyme pretreatment.

    PubMed

    Abedinia, Ahmadreza; Ariffin, Fazilah; Huda, Nurul; Nafchi, Abdorreza Mohammadi

    2017-05-01

    The effects of different pretreatments on yield and composition of extraction, physicochemical, and rheological properties of duck feet gelatin (DFG) were investigated. Gelatins were extracted from the whole feet of Pekin duck with an average yield of 4.09%, 3.65%, and 5.75% for acidic (Ac-DFG), alkaline (Al-DFG), and enzymatic (En-DFG) pretreatment on a wet weight basis, respectively. Proteins at 81.38%, 79.41%, 82.55%, and 87.38% were the major composition for Ac-DFG, Al-DFG, En-DFG, and bovine, respectively. Amino acid analysis showed glycine as the predominant amino acid in Ac-DFG, followed by hydroxyproline, proline, and alanine for Ac-DFG, Al-DFG, and En-DFG, respectively. Rheological analysis indicated that the maximum elastic modulus (9972.25Pa) and loss modulus (4956.28Pa) for Ac-DFG gelatin were significantly higher than those of other gelatins. Extracted gelatins contained α1 and α2 chains as the predominant components, and enzymatic gelatin had low molecular weight peptides. Fourier transform infrared spectroscopy showed that the peak of the gelatins was mainly positioned in the amide band region (amides I, II, and III). A considerable loss of molecular-order triple helical structure was also observed after pepsin treatment. In summary, duck feet gelatin has potential to replace as mammalian gelatin in food and pharmaceutical industry.

  20. Detoxification of acid pretreated spruce hydrolysates with ferrous sulfate and hydrogen peroxide improves enzymatic hydrolysis and fermentation.

    PubMed

    Soudham, Venkata Prabhakar; Brandberg, Tomas; Mikkola, Jyri-Pekka; Larsson, Christer

    2014-08-01

    The aim of the present work was to investigate whether a detoxification method already in use during waste water treatment could be functional also for ethanol production based on lignocellulosic substrates. Chemical conditioning of spruce hydrolysate with hydrogen peroxide (H₂O₂) and ferrous sulfate (FeSO₄) was shown to be an efficient strategy to remove significant amounts of inhibitory compounds and, simultaneously, to enhance the enzymatic hydrolysis and fermentability of the substrates. Without treatment, the hydrolysates were hardly fermentable with maximum ethanol concentration below 0.4 g/l. In contrast, treatment by 2.5 mM FeSO₄ and 150 mM H₂O₂ yielded a maximum ethanol concentration of 8.3 g/l.

  1. Protective effect of cholesterol-loaded cyclodextrin pretreatment against hydrogen peroxide induced oxidative damage in ram sperm.

    PubMed

    Naseer, Zahid; Ahmad, Ejaz; Aksoy, Melih; Küçük, Niyazi; Serin, İlker; Ceylan, Ahmet; Boyacıoğlu, Murat; Kum, Cavit

    2015-08-01

    Three experiments were conducted to determine the protective effect of cholesterol-loaded cyclodextrin (CLC) against hydrogen peroxide (H2O2) or cryo-induced damage in ram sperm. In Experiment 1, the fresh ejaculates were either treated with CLC or remained untreated. Both CLC treated and untreated samples were then incubated with 0, 250 or 500 μM H2O2 at 35°C for 12 h. After incubation period of 12 h, the motility, viability and membrane integrity remained higher in CLC treated sperm even in the presence of 250 or 500 μM H2O2. The H2O2 treatment affected all the sperm parameters adversely (P<0.05). However, compared to CLC untreated counterpart, the motility, viability and membrane integrity remained higher (P<0.05) in treated sperm, even in the presence of 250 or 500 μM H2O2 during 12 h of incubation. In Experiment 2, semen was cryopreserved in the presence or absence of CLC. The post-thaw results revealed that CLC treated sperm has higher (P<0.05) motility, viability and membrane integrity compared to the control. In Experiment 3, lipid peroxidation levels were assessed by determining malondialdehyde (MDA) concentrations during the H2O2-induced oxidative stress in CLC treated and untreated sperm. However, no difference (P>0.05) in MDA level was observed among the groups at any stage of incubation. In conclusion, the CLC incorporation in ram sperm membrane may protects it against H2O2 or cryo-induced oxidative damage. The cryoprotective influence of CLC on ram sperm might be resulted from, at least partly, its antioxidative property.

  2. Identification of oleaginous yeast strains able to accumulate high intracellular lipids when cultivated in alkaline pretreated corn stover

    PubMed Central

    Sitepu, Irnayuli R.; Jin, Mingjie; Fernandez, J. Enrique; da Costa Sousa, Leonardo; Balan, Venkatesh; Boundy-Mills, Kyria L.

    2015-01-01

    Microbial oil is a potential alternative to food/plant-derived biodiesel fuel. Our previous screening studies identified a wide range of oleaginous yeast species, using a defined laboratory medium known to stimulate lipid accumulation. In this study, the ability of these yeasts to grow and accumulate lipids was further investigated in synthetic hydrolysate (SynH) and authentic ammonia fiber expansion (AFEX™)-pretreated corn stover hydrolysate (ACSH). Most yeast strains tested were able to accumulate lipids in SynH, but only a few were able to grow and accumulate lipids in ACSH medium. Cryptococcus humicola UCDFST 10-1004 was able to accumulate as high as 15.5 g/L lipids, out of a total of 36 g/L cellular biomass when grown in ACSH, with a cellular lipid content of 40% of cell dry weight. This lipid production is among the highest reported values for oleaginous yeasts grown in authentic hydrolysate. Pre-culturing in SynH media with xylose as sole carbon source enabled yeasts to assimilate both glucose and xylose more efficiently in the subsequent hydrolysate medium. This study demonstrates that ACSH is a suitable medium for certain oleaginous yeasts to convert lignocellullosic sugars to triacylglycerols for production of biodiesel and other valuable oleochemicals. PMID:25052467

  3. Pre-treatment serum alkaline phosphatase and lactate dehydrogenase as prognostic factors in triple negative breast cancer

    PubMed Central

    Chen, Bo; Dai, Danian; Tang, Hailin; Chen, Xi; Ai, Xiaohong; Huang, Xiaojia; Wei, Weidong; Xie, Xiaoming

    2016-01-01

    Background: Serum parameters as prognostic parameters are studied widely. We aim to examine the prognostic significance of the serum alkaline phosphatase (ALP) level and lactate dehydrogenase (LDH) level in triple negative breast cancer (TNBC). Methods: Total of 253 TNBC patients from Sun Yat-sen University Cancer Center who underwent treatment between January 2004 and December 2009 was conducted in this retrospective study. Before treatment serum ALP and LDH levels were routinely measured. We use the receiver operating characteristic (ROC) curve analysis to estimate the cutoff value of serum ALP and LDH levels. The Kaplan-Meier method and multivariable Cox regression analysis were used for Disease free survival (DFS) and overall survival (OS) assessed. Results: The ROC curves determined that the optimum cutoff point for ALP and LDH were 66.5u/L and 160.5u/L, respectively. The elevated ALP and LDH were both significantly associated with decreased DFS and OS (both P < 0.001). In addition, the entire cohort was stratified into three subgroups basis of ALP levels and LDH levels. TNBC Patients who with ALP >66.5 u/L and LDH >160.5u/L had the worst DFS and OS (both P < 0.001). In TNBC patients, univariate and multivariate Cox regression analyses conformed ALP and LDH were independent unfavorable prognostic factors for DFS and OS. Conclusions: The serum levels of ALP and LDH before treatment are independent prognostic parameters and may serve as complement to help predict survival in TNBC. PMID:27994669

  4. Construction of Aspergillus niger integrated with cellulase gene from Ampullaria gigas Spix for improved enzyme production and saccharification of alkaline-pretreated rice straw.

    PubMed

    Yang, Peizhou; Zhang, Haifeng; Cao, Lili; Zheng, Zhi; Jiang, Shaotong

    2016-12-01

    Aspergillus niger is an important microorganism that has been used for decades to produce extracellular enzymes. In this study, a novel Aspergillus niger strain integrated with a eukaryotic expression vector harboring the gpd-Shi promoter of shiitake mushrooms and cellulase gene of Ampullaria gigas Spix was engineered to improve cellulase production for the achievement of highly efficient saccharification of agricultural residues. In one strain, designated ACShi27, which exhibited the highest total cellulase expression, total cellulase, endoglucanase, exoglucanase, and xylanase expression levels were 1.73, 16.23, 17.73, and 150.83 U ml(-1), respectively; these values were 14.5, 22.3, 24.6, and 17.3% higher than those of the wild-type Aspergillus niger M85 using wheat bran as an induction substrate. Production of cellulases and xylanase by solid-state fermentation followed by in situ saccharification of ACShi27 was investigated with alkaline-pretreated rice straw as a substrate. After 2 days of enzyme induction at 30 °C, followed by 48 h of saccharification at 50 °C, the conversion rate of carbon polymers into reducing sugar reached 293.2 mg g(-1), which was 1.23-fold higher than that of the wild-type strain. The expression of sestc in Aspergillus niger can improve the total cellulase and xylanase activity and synergism, thereby enhancing the lignocellulose in situ saccharification.

  5. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    SciTech Connect

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; Fountain, Mackenzie; Ralph, John; Hodge, David B.; Hegg, Eric L.

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10 h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin

  6. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    DOE PAGES

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; ...

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10more » h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin from untreated poplar. In conclusion: This study demonstrated that the fed

  7. Coupling alkaline pre-extraction with alkaline-oxidative post-treatment of corn stover to enhance enzymatic hydrolysis and fermentability

    PubMed Central

    2014-01-01

    Background A two-stage chemical pretreatment of corn stover is investigated comprising an NaOH pre-extraction followed by an alkaline hydrogen peroxide (AHP) post-treatment. We propose that conventional one-stage AHP pretreatment can be improved using alkaline pre-extraction, which requires significantly less H2O2 and NaOH. To better understand the potential of this approach, this study investigates several components of this process including alkaline pre-extraction, alkaline and alkaline-oxidative post-treatment, fermentation, and the composition of alkali extracts. Results Mild NaOH pre-extraction of corn stover uses less than 0.1 g NaOH per g corn stover at 80°C. The resulting substrates were highly digestible by cellulolytic enzymes at relatively low enzyme loadings and had a strong susceptibility to drying-induced hydrolysis yield losses. Alkaline pre-extraction was highly selective for lignin removal over xylan removal; xylan removal was relatively minimal (~20%). During alkaline pre-extraction, up to 0.10 g of alkali was consumed per g of corn stover. AHP post-treatment at low oxidant loading (25 mg H2O2 per g pre-extracted biomass) increased glucose hydrolysis yields by 5%, which approached near-theoretical yields. ELISA screening of alkali pre-extraction liquors and the AHP post-treatment liquors demonstrated that xyloglucan and β-glucans likely remained tightly bound in the biomass whereas the majority of the soluble polymeric xylans were glucurono (arabino) xylans and potentially homoxylans. Pectic polysaccharides were depleted in the AHP post-treatment liquor relative to the alkaline pre-extraction liquor. Because the already-low inhibitor content was further decreased in the alkaline pre-extraction, the hydrolysates generated by this two-stage pretreatment were highly fermentable by Saccharomyces cerevisiae strains that were metabolically engineered and evolved for xylose fermentation. Conclusions This work demonstrates that this two

  8. Impact of bleaching on subcritical water- and Formosolv-pretreated tulip tree to enhance enzyme accessibility.

    PubMed

    Myint, Aye Aye; Kim, Dae Sung; Lee, Hun Wook; Yoon, Junho; Choi, In-Gyu; Choi, Joon Weon; Lee, Youn-Woo

    2013-10-01

    A novel method was developed for fractionating cellulose microfibrils from forest residue (tulip tree sawdust) to enhance cellulose digestibility, particularly at minimum enzyme loadings. This method involved three main stages: selective hemicellulose solubilization by subcritical water (SCW) pretreatment, delignification of the SCW-pretreated solids using the Formosolv process, and deformylation/bleaching of the cellulose pulp with alkaline hydrogen peroxide solution. This process produced nearly 98% white cellulose microfibrils with 23-fold higher conversion to glucose as compared to the raw substrate after 72 h of enzymatic hydrolysis. This study showed that cellulose swelling had the greatest effect on the enzymatic hydrolysis efficiency of delignified pulp obtained by the Formosolv process.

  9. 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.

  10. A new process for efficiently producing methane from waste activated sludge: alkaline pretreatment of sludge followed by treatment of fermentation liquid in an EGSB reactor.

    PubMed

    Zhang, Dong; Chen, Yinguang; Zhao, Yuxiao; Ye, Zhengxiang

    2011-01-15

    In the literature the production of methane from waste activated sludge (WAS) was usually conducted in a continuous stirred tank reactor (CSTR) after sludge was pretreated. It was reported in our previous publication that compared with other pretreatment methods the methane production in CSTR could be significantly enhanced when sludge was pretreated by NaOH at pH 10 for 8 days. In order to further improve methane production, this study reported a new process for efficiently producing methane from sludge, that is, sludge was fermented at pH 10 for 8 days, which was adjusted by Ca(OH)(2), and then the fermentation liquid was treated in an expanded granular sludge bed (EGSB) for methane generation. First, for comparing the methane production observed in this study with that reported in the literature, the conventional operational model was applied to produce methane from the pH 10 pretreated sludge, that is, directly using the pH 10 pretreated sludge to produce methane in a CSTR. It was observed that the maximal methane production was only 0.61 m(3)CH(4)/m(3)-reactor/day. Then, the use of fermentation liquid of pH 10 pretreated sludge to produce methane in the reactors of up-flow anaerobic sludge bed (UASB), anaerobic sequencing batch reactor (ASBR) and EGSB was compared. The maximal methane production in UASB, ASBR, and EGSB reached 1.41, 3.01, and 12.43 m(3)CH(4)/m(3)-reactor/day, respectively. Finally, the mechanisms for EGSB exhibiting remarkably higher methane production were investigated by enzyme, adenosine-triphosphate (ATP), scanning electron microscope (SEM) and fluorescence in situ hybridization (FISH) analyses. It was found that the granular sludge in EGSB had the highest conversion efficiency of acetic acid to methane, and the greatest activity of hydrolysis and acidification enzymes and general physiology with much more Methanosarcinaceae.

  11. Optimization of pretreatment, enzymatic hydrolysis and fermentation for more efficient ethanol production by Jerusalem artichoke stalk.

    PubMed

    Li, Kai; Qin, Jin-Cheng; Liu, Chen-Guang; Bai, Feng-Wu

    2016-12-01

    Jerusalem artichoke (JA) is a potential energy crop for biorefinery due to its unique agronomic traits such as resistance to environmental stresses and high biomass yield in marginal lands. Although JA tubers have been explored for inulin extraction and biofuels production, there is little concern on its stalk (JAS). In this article, the pretreatment of JAS by alkaline hydrogen peroxide was optimized using the response surface methodology to improve sugars yield and reduce chemicals usage. Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to characterize the structures of the pretreated JAS to evaluate the effectiveness of the pretreatment. Furthermore, the feeding of the pretreated JAS and cellulase was performed for high solid uploading (up to 30%) to increase ethanol titer, and simultaneous saccharification and fermentation with 55.6g/L ethanol produced, 36.5% more than that produced through separate hydrolysis and fermentation, was validated to be more efficient.

  12. Bioethanol production from sodium hydroxide/hydrogen peroxide-pretreated water hyacinth via simultaneous saccharification and fermentation with a newly isolated thermotolerant Kluyveromyces marxianu strain.

    PubMed

    Yan, Jinping; Wei, Zhilei; Wang, Qiaoping; He, Manman; Li, Shumei; Irbis, Chagan

    2015-10-01

    In this study, bioethanol production from NaOH/H2O2-pretreated water hyacinth was investigated. Pretreatment of water hyacinth with 1.5% (v/v) H2O2 and 3% (w/v) NaOH at 25 °C increased the production of reducing sugars (223.53 mg/g dry) and decreased the cellulose crystallinity (12.18%), compared with 48.67 mg/g dry and 22.80% in the untreated sample, respectively. The newly isolated Kluyveromyces marxianu K213 showed greater ethanol production from glucose (0.43 g/g glucose) at 45 °C than did the control Saccharomyces cerevisiae angel yeast. The maximum ethanol concentration (7.34 g/L) achieved with K. marxianu K213 by simultaneous saccharification and fermentation (SSF) from pretreated water hyacinth at 42 °C was 1.78-fold greater than that produced by angel yeast S. cerevisiae at 30 °C. The present work demonstrates that bioethanol production achieved via SSF of NaOH/H2O2-pretreated water hyacinth with K. marxianu K213 is a promising strategy to utilize water hyacinth biomass.

  13. High level extracellular production of a recombinant alkaline catalase in E. coli BL21 under ethanol stress and its application in hydrogen peroxide removal after cotton fabrics bleaching.

    PubMed

    Yu, Zhenxiao; Zheng, Hongchen; Zhao, Xingya; Li, Shufang; Xu, Jianyong; Song, Hui

    2016-08-01

    The effects of induction parameters, osmolytes and ethanol stress on the productivity of the recombinant alkaline catalase (KatA) in Escherichia coli BL21 (pET26b-KatA) were investigated. The yield of soluble KatA was significantly enhanced by 2% ethanol stress. And a certain amount of Triton X-100 supplementation could markedly improved extracellular ratio of KatA. A total soluble catalase activity of 78,762U/mL with the extracellular ratio of 92.5% was achieved by fed-batch fermentation in a 10L fermentor, which was the highest yield so far. The purified KatA showed high stability at 50°C and pH 6-10. Application of KatA for elimination of H2O2 after cotton fabrics bleaching led to less consumption of water, steam and electric power by 25%, 12% and 16.7% respectively without productivity and quality losing of cotton fabrics. Thus, the recombinant KatA is a promising candidate for industrial production and applications.

  14. Alkali-based pretreatments distinctively extract lignin and pectin for enhancing biomass saccharification by altering cellulose features in sugar-rich Jerusalem artichoke stem.

    PubMed

    Li, Meng; Wang, Jun; Yang, Yuezhou; Xie, Guanghui

    2016-05-01

    Jerusalem artichoke (JA) has been known as a potential nonfood feedstock for biofuels. Based on systems analysis of total 59 accessions, both soluble sugar and ash could positively affect biomass digestibility after dilute sodium hydroxide pretreatment (A). In this study, one representative accession (HEN-3) was used to illustrate its enzymatic digestibility with pretreatments of ultrasonic-assisted dilute sodium hydroxide (B), alkaline peroxide (C), and ultrasonic-assisted alkaline peroxide (D). Pretreatment D exhibited the highest hexose release rate (79.4%) and total sugar yield (10.4 g/L), which were 2.4 and 2.6 times higher, respectively, than those of the control. The analysis of cellulose crystalline index (CrI), cellulose degree of polymerization (DP), thermal behavior and SEM suggested that alkali-based pretreatments could distinctively extract lignin and pectin polymers, leading to significant alterations of cellulose CrI and DP for high biomass saccharification. Additionally, hydrogen peroxide (H2O2) could significant reduce the generation of fermentation inhibitors during alkali-based pretreatments.

  15. Effect of heat-alkaline treatment as a pretreatment method on volatile fatty acid production and protein degradation in excess sludge, pure proteins and pure cultures.

    PubMed

    Tan, Reasmey; Miyanaga, Kazuhiko; Uy, Davin; Tanji, Yasunori

    2012-08-01

    This study investigated the effect of heat-alkaline treatment (HAT) at pH 11 and 60 °C on volatile fatty acid (VFA) production and protein degradation in excess sludge, soluble and insoluble proteins, and pure cultures. In addition, quantification of bacteria present in the sludge was also examined. Experimental results showed that following acid fermentation under pH 7 and 37 °C, HAT enhanced VFA production in excess sludge, albumin, and Gram-negative bacteria, but not in casein or Gram-positive bacteria. Protein solubility was therefore found not to be the main criteria for VFA production. In the protein analysis, it was shown that the outer membrane protein (OmpC) of Escherichia coli K12 was resistant to chemical and enzymatic hydrolysis. Gram staining revealed that Gram-negative bacteria were predominant in the activated sludge used in this study. In addition, the bacteria present in the activated sludge comprised only 10% of mixed liquor suspended solids (MLSS) by quantitative PCR.

  16. Comparison of acid-detergent lignin, alkaline-peroxide lignin, and acid-detergent insoluble ash as internal markers for predicting fecal output and digestibility by cattle offered bermudagrass hays of varying nutrient composition

    PubMed Central

    2014-01-01

    Background The potential for acid-detergent insoluble ash (ADIA), alkaline-peroxide lignin (APL), and acid-detergent lignin (ADL) to predict fecal output (FO) and dry matter digestibility (DMD) by cattle offered bermudagrass [Cynodon dactylon (L.) Pers.] hays of different qualities was evaluated. Eight ruminally cannulated cows (594 ± 35.5 kg) were allocated randomly to 4 hay diets: low (L), medium low (ML), medium high (MH), and high (H) crude protein (CP) concentration (79, 111, 131, and 164 g CP/kg on a DM basis, respectively). Diets were offered in 3 periods with 2 diet replicates per period and were rotated across cows between periods. Cows were individually fed 20 g DM/kg of body weight in equal feedings at 08:00 and 16:00 h for a 10-d adaptation followed by a 5-d total fecal collection. Actual DM intake (DMI), DMD, and FO were determined based on hay offered, ort, and feces excreted. These components were then analyzed for ADL, APL, and ADIA concentration to determine marker recovery and marker-based estimates of FO and DMD. Results Forage DMI was affected by diet (P = 0.02), and DMI from MH and H was greater (P < 0.05) than from L. Apparent DMD tended (P = 0.08) to differ among diets while FO (P = 0.20) was not affected by diet treatments. Average ADL recovery (1.16) was greater (P < 0.05) than that of ADIA (1.03) and APL (1.06), but ADIA and APL did not differ (P = 0.42). Estimates of FO and DMD derived using APL and ADIA were not different (P ≥ 0.05) from total fecal collection while those using ADL differed (P < 0.05). There was no diet by marker interaction (P ≥ 0.22) for either FO or DMD. Conclusion Acid-detergent insoluble ash and APL accurately predicted FO and DMD of cattle fed bermudagrass hay of varying nutrient composition. These internal markers may facilitate studies involving large numbers of animals and forages. Results from such studies may be used to develop improved equations to predict energy values of

  17. Peroxide-induced cell death and lipid peroxidation in C6 glioma cells.

    PubMed

    Linden, Arne; Gülden, Michael; Martin, Hans-Jörg; Maser, Edmund; Seibert, Hasso

    2008-08-01

    Peroxides are often used as models to induce oxidative damage in cells in vitro. The aim of the present study was to elucidate the role of lipid peroxidation in peroxide-induced cell death. To this end (i) the ability to induce lipid peroxidation in C6 rat astroglioma cells of hydrogen peroxide (H2O2), cumene hydroperoxide (CHP) and t-butyl hydroperoxide (t-BuOOH) (ii) the relation between peroxide-induced lipid peroxidation and cell death in terms of time and concentration dependency and (iii) the capability of the lipid peroxidation chain breaking alpha-tocopherol to prevent peroxide-induced lipid peroxidation and/or cell death were investigated. Lipid peroxidation was characterised by measuring thiobarbituric acid reactive substances (TBARS) and, by HPLC, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE) and hexanal. Within 2 h CHP, t-BuOOH and H2O2 induced cell death with EC50 values of 59+/-9 microM, 290+/-30 microM and 12+/-1.1 mM, respectively. CHP and t-BuOOH, but not H2O2 induced lipid peroxidation in C6 cells with EC50 values of 15+/-14 microM and 130+/-33 microM, respectively. The TBARS measured almost exclusively consisted of MDA. 4-HNE was mostly not detectable. The concentration of hexanal slightly increased with increasing concentrations of organic peroxides. Regarding time and concentration dependency lipid peroxidation preceded cell death. Pretreatment with alpha-tocopherol (10 microM, 24 h) prevented both, peroxide-induced lipid peroxidation and cell death. The results strongly indicate a major role of lipid peroxidation in the killing of C6 cells by organic peroxides but also that lipid peroxidation is not involved in H2O2 induced cell death.

  18. Electrochemical Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    Tennakoon, Charles L. K.; Singh, Waheguru; Anderson, Kelvin C.

    2010-01-01

    Two-electron reduction of oxygen to produce hydrogen peroxide is a much researched topic. Most of the work has been done in the production of hydrogen peroxide in basic media, in order to address the needs of the pulp and paper industry. However, peroxides under alkaline conditions show poor stabilities and are not useful in disinfection applications. There is a need to design electrocatalysts that are stable and provide good current and energy efficiencies to produce hydrogen peroxide under acidic conditions. The innovation focuses on the in situ generation of hydrogen peroxide using an electrochemical cell having a gas diffusion electrode as the cathode (electrode connected to the negative pole of the power supply) and a platinized titanium anode. The cathode and anode compartments are separated by a readily available cation-exchange membrane (Nafion 117). The anode compartment is fed with deionized water. Generation of oxygen is the anode reaction. Protons from the anode compartment are transferred across the cation-exchange membrane to the cathode compartment by electrostatic attraction towards the negatively charged electrode. The cathode compartment is fed with oxygen. Here, hydrogen peroxide is generated by the reduction of oxygen. Water may also be generated in the cathode. A small amount of water is also transported across the membrane along with hydrated protons transported across the membrane. Generally, each proton is hydrated with 3-5 molecules. The process is unique because hydrogen peroxide is formed as a high-purity aqueous solution. Since there are no hazardous chemicals or liquids used in the process, the disinfection product can be applied directly to water, before entering a water filtration unit to disinfect the incoming water and to prevent the build up of heterotrophic bacteria, for example, in carbon based filters. The competitive advantages of this process are: 1. No consumable chemicals are needed in the process. The only raw materials

  19. Hydrogen peroxide poisoning

    MedlinePlus

    Hydrogen peroxide is used in these products: Hydrogen peroxide Hair bleach Some contact lens cleaners Note: Household hydrogen peroxide has a 3% concentration. That means it contains 97% water and 3% hydrogen peroxide. Hair ...

  20. Biomass pretreatment

    DOEpatents

    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.

  1. Lignocellulosic biomass pretreatment using AFEX.

    PubMed

    Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P S; Marshall, Derek; Dale, Bruce E

    2009-01-01

    Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

  2. Lignocellulosic Biomass Pretreatment Using AFEX

    NASA Astrophysics Data System (ADS)

    Balan, Venkatesh; Bals, Bryan; Chundawat, Shishir P. S.; Marshall, Derek; Dale, Bruce E.

    Although cellulose is the most abundant organic molecule, its susceptibility to hydrolysis is restricted due to the rigid lignin and hemicellulose protection surrounding the cellulose micro fibrils. Therefore, an effective pretreatment is necessary to liberate the cellulose from the lignin-hemicellulose seal and also reduce cellulosic crystallinity. Some of the available pretreatment techniques include acid hydrolysis, steam explosion, ammonia fiber expansion (AFEX), alkaline wet oxidation, and hot water pretreatment. Besides reducing lignocellulosic recalcitrance, an ideal pretreatment must also minimize formation of degradation products that inhibit subsequent hydrolysis and fermentation. AFEX is an important pretreatment technology that utilizes both physical (high temperature and pressure) and chemical (ammonia) processes to achieve effective pretreatment. Besides increasing the surface accessibility for hydrolysis, AFEX promotes cellulose decrystallization and partial hemicellulose depolymerization and reduces the lignin recalcitrance in the treated biomass. Theoretical glucose yield upon optimal enzymatic hydrolysis on AFEX-treated corn stover is approximately 98%. Furthermore, AFEX offers several unique advantages over other pretreatments, which include near complete recovery of the pretreatment chemical (ammonia), nutrient addition for microbial growth through the remaining ammonia on pretreated biomass, and not requiring a washing step during the process which facilitates high solid loading hydrolysis. This chapter provides a detailed practical procedure to perform AFEX, design the reactor, determine the mass balances, and conduct the process safely.

  3. Lime Pretreatment

    NASA Astrophysics Data System (ADS)

    Sierra, Rocio; Granda, Cesar Benigno; Holtzapple, Mark T.

    Lime pretreatment has proven to be a useful method for selectively reducing the lignin content of lignocellulosic biomass without significant loss in carbohydrates, thus realizing an important increase in biodigestibility. In lime pretreatment, the biomass is pretreated with calcium hydroxide and water under different conditions of temperature and pressure. It can be accomplished in one of three fashions: (1) short-term pretreatment that lasts up to 6 h, requires temperatures of 100-160°C, and can be applied with or without oxygen (pressure ~200 psig); (2) long-term pretreatment taking up to 8 weeks, requiring only 55-65°C, and capable of running with or without air (atmospheric pressure); and (3) simple pretreatment requiring 1 h in boiling water, without air or oxygen. Nonoxidative conditions are effective at low lignin contents (below ~18% lignin), whereas oxidative conditions are required for high lignin contents (above ~18% lignin).

  4. Lime pretreatment.

    PubMed

    Sierra, Rocio; Granda, Cesar Benigno; Holtzapple, Mark T

    2009-01-01

    Lime pretreatment has proven to be a useful method for selectively reducing the lignin content of lignocellulosic biomass without significant loss in carbohydrates, thus realizing an important increase in biodigestibility. In lime pretreatment, the biomass is pretreated with calcium hydroxide and water under different conditions of temperature and pressure. It can be accomplished in one of three fashions: (1) short-term pretreatment that lasts up to 6 h, requires temperatures of 100-160 degrees C, and can be applied with or without oxygen (pressure approximately 200 psig); (2) long-term pretreatment taking up to 8 weeks, requiring only 55-65 degrees C, and capable of running with or without air (atmospheric pressure); and (3) simple pretreatment requiring 1 h in boiling water, without air or oxygen. Nonoxidative conditions are effective at low lignin contents (below approximately 18% lignin), whereas oxidative conditions are required for high lignin contents (above approximately 18% lignin).

  5. 183W NMR Study of Peroxotungstates Involved in the Disproportionation of Hydrogen Peroxide into Singlet Oxygen ((1)O(2), (1)Delta(g)) Catalyzed by Sodium Tungstate in Neutral and Alkaline Water.

    PubMed

    Nardello, V.; Marko, J.; Vermeersch, G.; Aubry, J. M.

    1998-10-19

    The disproportionation of aqueous hydrogen peroxide catalyzed by sodium tungstate has been investigated with regard to the multiplicity of the oxygen molecules released. Trapping experiments and detection of the IR luminescence of (1)O(2) have shown that the yield of (1)O(2) is virtually quantitative. The mono-, di-, and tetraperoxotungstate intermediates W(O(2))(n)()O(4)(-)(n)()(2)(-) (n = 1, 2, 4) have been characterized by UV and (183)W NMR spectroscopies. The diperoxo species is proposed as the precursor of (1)O(2).

  6. Rapid and effective oxidative pretreatment of woody biomass at mild reaction conditions and low oxidant loadings

    PubMed Central

    2013-01-01

    Background One route for producing cellulosic biofuels is by the fermentation of lignocellulose-derived sugars generated from a pretreatment that can be effectively coupled with an enzymatic hydrolysis of the plant cell wall. While woody biomass exhibits a number of positive agronomic and logistical attributes, these feedstocks are significantly more recalcitrant to chemical pretreatments than herbaceous feedstocks, requiring higher chemical and energy inputs to achieve high sugar yields from enzymatic hydrolysis. We previously discovered that alkaline hydrogen peroxide (AHP) pretreatment catalyzed by copper(II) 2,2΄-bipyridine complexes significantly improves subsequent enzymatic glucose and xylose release from hybrid poplar heartwood and sapwood relative to uncatalyzed AHP pretreatment at modest reaction conditions (room temperature and atmospheric pressure). In the present work, the reaction conditions for this catalyzed AHP pretreatment were investigated in more detail with the aim of better characterizing the relationship between pretreatment conditions and subsequent enzymatic sugar release. Results We found that for a wide range of pretreatment conditions, the catalyzed pretreatment resulted in significantly higher glucose and xylose enzymatic hydrolysis yields (as high as 80% for both glucose and xylose) relative to uncatalyzed pretreatment (up to 40% for glucose and 50% for xylose). We identified that the extent of improvement in glucan and xylan yield using this catalyzed pretreatment approach was a function of pretreatment conditions that included H2O2 loading on biomass, catalyst concentration, solids concentration, and pretreatment duration. Based on these results, several important improvements in pretreatment and hydrolysis conditions were identified that may have a positive economic impact for a process employing a catalyzed oxidative pretreatment. These improvements include identifying that: (1) substantially lower H2O2 loadings can be used that

  7. Improving the hydrogen peroxide bleaching efficiency of aspen chemithermomechanical pulp by using chitosan.

    PubMed

    Li, Zongquan; Dou, Hongyan; Fu, Yingjuan; Qin, Menghua

    2015-11-05

    The presence of transition metals during the hydrogen peroxide bleaching of pulp results in the decomposition of hydrogen peroxide, which decreases the bleaching efficiency. In this study, chitosans were used as peroxide stabilizer in the alkaline hydrogen peroxide bleaching of aspen chemithermomechanical pulp (CTMP). The results showed that the brightness of the bleached CTMP increased 1.5% ISO by addition of 0.1% chitosan with 95% degree of deacetylation during peroxide bleaching. Transition metals in the form of ions or metal colloid particles, such as iron, copper and manganese, could be adsorbed by chitosans. Chitosans could inhibit the decomposition of hydrogen peroxide catalyzed by different transition metals under alkaline conditions. The ability of chitosans to inhibit peroxide decomposition depended on the type of transition metals, chitosan concentration and degree of deacetylation applied. The addition of chitosan slightly reduced the concentration of the hydroxyl radical formed during the hydrogen peroxide bleaching of aspen CTMP.

  8. Pretreatment of lignocellulosic biomass using Fenton chemistry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pretreatment is a necessary step in “biomass to biofuel conversion” due to the recalcitrant nature of lignocellulosic biomass. White-rot fungi utilize peroxidases and hydrogen peroxide (in vivo Fenton chemistry) to degrade lignin. In an attempt to mimic this process, solution phase Fenton chemistry ...

  9. Alkene anti-Dihydroxylation with Malonoyl Peroxides.

    PubMed

    Alamillo-Ferrer, Carla; Davidson, Stuart C; Rawling, Michael J; Theodoulou, Natalie H; Campbell, Matthew; Humphreys, Philip G; Kennedy, Alan R; Tomkinson, Nicholas C O

    2015-10-16

    Malonoyl peroxide 1, prepared in a single step from the commercially available diacid, is an effective reagent for the anti-dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of acetic acid at 40 °C followed by alkaline hydrolysis leads to the corresponding diol (35-92%) with up to 13:1 anti-selectivity. A mechanism consistent with experimental findings is proposed that accounts for the selectivity observed.

  10. Reuse of microalgae grown in full-scale wastewater treatment ponds: Thermochemical pretreatment and biogas production.

    PubMed

    Passos, Fabiana; Felix, Leonardo; Rocha, Hemyle; Pereira, Jackson de Oliveira; de Aquino, Sérgio

    2016-06-01

    This study assessed thermochemical pretreatment of microalgae harvested from a full-scale wastewater treatment pond prior to its anaerobic digestion using acid and alkaline chemical doses combined with thermal pretreatment at 80°C. Results indicated that alkaline and thermal pretreatment contributed mostly to glycoprotein and pectin solubilisation; whilst acid pretreatment solubilised mostly hemicellulose, with lower effectiveness for proteins. Regarding the anaerobic biodegradability, biochemical methane potential (BMP) tests showed that final methane yield was enhanced after almost all pretreatment conditions when compared to non-pretreated microalgae, with the highest increase for thermochemical pretreatment at the lowest dose (0.5%), i.e. 82% and 86% increase for alkaline and acid, respectively. At higher doses, salt toxicity was revealed by K(+) concentrations over 5000mg/L. All BMP data from pretreated biomass was successfully described by the modified Gompertz model and optimal condition (thermochemical 0.5% HCl) showed an increase in final methane yield and the process kinetics.

  11. Hazard Assessment of Personal Protective Clothing for Hydrogen Peroxide Service

    NASA Technical Reports Server (NTRS)

    Greene, Ben; McClure, Mark B.; Johnson, Harry T.

    2004-01-01

    Selection of personal protective equipment (PPE) for hydrogen peroxide service is an important part of the hazard assessment process. But because drip testing of chemical protective clothing for hydrogen peroxide service has not been reported for about 40 years, it is of great interest to test new protective clothing materials with new, high-concentration hydrogen peroxide following similar procedures. The suitability of PPE for hydrogen peroxide service is in part determined by observations made when hydrogen peroxide is dripped onto swatches of protective clothing material. Protective clothing material was tested as received, in soiled condition, and in grossly soiled condition. Materials were soiled by pretreating the material with potassium permanganate (KMnO4) solution then drying to promote a reaction. Materials were grossly soiled with solid KMnO4 to greatly promote reaction. Observations of results including visual changes to the hydrogen peroxide and materials, times to ignition, and self-extinguishing characteristics of the materials are reported.

  12. Concentration of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2006-01-01

    Methods for concentrating hydrogen peroxide solutions have been described. The methods utilize a polymeric membrane separating a hydrogen peroxide solution from a sweep gas or permeate. The membrane is selective to the permeability of water over the permeability of hydrogen peroxide, thereby facilitating the concentration of the hydrogen peroxide solution through the transport of water through the membrane to the permeate. By utilizing methods in accordance with the invention, hydrogen peroxide solutions of up to 85% by volume or higher may be generated at a point of use without storing substantial quantities of the highly concentrated solutions and without requiring temperatures that would produce explosive mixtures of hydrogen peroxide vapors.

  13. PRECIPITATION OF PLUTONOUS PEROXIDE

    DOEpatents

    Barrick, J.G.; Manion, J.P.

    1961-08-15

    A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

  14. Involvement of lipid peroxidation and organic peroxides in UVA-induced matrix metalloproteinase-1 expression.

    PubMed

    Polte, Tobias; Tyrrell, Rex M

    2004-06-15

    Ultraviolet A (UVA) irradiation causes human skin aging and skin cancer at least partially through the activation of matrix metalloproteinases (MMPs). MMP-1, the interstitial collagenase, is responsible for the degradation of collagen and is involved in tumor progression in human skin. The present study uses human skin fibroblast cells (FEK4) to investigate the involvement of lipid peroxidation and the role of peroxides as possible mediators in MMP-1 activation by UVA. Preincubation with the antioxidants butylated hydroxytoluene and Trolox reduced UVA-dependent MMP-1 upregulation, suggesting that peroxidation of membrane lipids is involved. Blocking the iron-driven generation of lipid peroxides and hydroxyl radicals by different iron chelators led to a decrease in UVA-induced MMP-1 mRNA accumulation. Moreover, modulation of glutathione peroxidase activity by use of the specific inhibitor mercaptosuccinate (MS) or by the depletion of glutathione (using buthionine-S, R-sulfoximine, BSO), enhanced the UVA-dependent MMP-1 response. Finally, UVA irradiation generated a significant increase in intracellular peroxide levels which is augmented by pretreatment of the cells with BSO or MS. Our results demonstrate that lipid peroxidation and the production of peroxides are important events in the signalling pathway of MMP-1 activation by UVA.

  15. Decolorization of methylene blue in aqueous suspensions of titanium peroxide.

    PubMed

    Ogino, Chiaki; Dadjour, Mahmoud Farshbaf; Iida, Yasuo; Shimizu, Nobuaki

    2008-05-01

    The pretreatment of TiO(2)-photocatalysts in solutions of H(2)O(2) was studied by examining the decolorization of methylene blue in the dark. Incubation of TiO(2) particles in H(2)O(2) solutions increased the oxidizing capacity of TiO(2). Methylene blue (0.3 mM) was degraded in the presence of pretreated TiO(2), and a decolorizing ratio of 47% was obtained after a 48-h incubation period in the presence of 5.0 g/L pretreated TiO(2). Titanium peroxide as a stable oxidant, which can be synthesized with the reaction of titanium sulfate and H(2)O(2), was studied in the decolorizing process of methylene blue. Concentrations of methylene blue were significantly reduced in the presence of titanium peroxide, and a greater extent of decolorization was obtained with larger amounts of titanium peroxide. A 63% decrease in methylene blue concentration was achieved in 5h incubation in the presence of 4.0 g/L titanium peroxide. H(2)O(2) accelerated the decolorizing process in the presence of titanium peroxide. The addition of 100 mM H(2)O(2) to a methylene blue solution containing 2.0 g/L titanium peroxide increased the decolorizing ratio to 85% after 5 h incubation. The addition of a hydroxyl radical scavenger, dimethyl sulfoxide, significantly decreased the decolorizing ratio, indicating the role of hydroxyl radicals in the oxidation process.

  16. Arsenic increased lipid peroxidation in rat tissues by a mechanism independent of glutathione levels.

    PubMed Central

    Ramos, O; Carrizales, L; Yáñez, L; Mejía, J; Batres, L; Ortíz, D; Díaz-Barriga, F

    1995-01-01

    The role of lipid peroxidation in the mechanism of arsenic toxicity was investigated in female rats pretreated with N-acetylcysteine (NAC, a glutathione [GSH] inducer) or with buthionine sulfoximine (BSO, a GSH depletor). Rats were challenged with sodium arsenite, and sacrificed 1 hr after this treatment. Results showed that arsenic decreased GSH levels and increased lipid peroxidation in liver, kidney, and heart, with a larger effect at 18.2 mg/kg than at 14.8 mg/kg for lipid peroxidation induction. In the liver of rats treated with arsenic, pretreatment with NAC increased the levels of GSH and decreased lipid peroxidation. In kidney and heart, NAC pretreatment protected the tissues against arsenic-induced depletion of GSH levels, but the same degree of protection was not found for lipid peroxidation induction. In its turn, BSO had an additive effect with arsenic in lowering the levels of GSH in the liver and kidney, but an inverse correlation between GSH levels and lipid peroxidation was found only in liver. Arsenic content in tissues of rats pretreated with NAC was lower than in rats treated only with arsenic. In rats with depleted levels of GSH (BSO-pretreated rats), a shift in arsenic tissue distribution was found, with higher levels in skin and lower levels in kidney. A clear tendency for a positive correlation between arsenic concentration and lipid peroxidation levels was found in liver, kidney, and heart. PMID:7621808

  17. Method for pretreating lignocellulosic biomass

    DOEpatents

    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. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  19. Anaerobic digestion of recalcitrant textile dyeing sludge with alternative pretreatment strategies.

    PubMed

    Xiang, Xinyi; Chen, Xiaoguang; Dai, Ruobin; Luo, Ying; Ma, Puyue; Ni, Shengsheng; Ma, Chengyu

    2016-12-01

    Abundant organic compounds in textile dyeing sludge (TDS) provide possibility for its anaerobic digestion (AD) treatment. However, preliminary test showed little biogas generation in direct AD of the TDS during 20days. In order to improve the AD availability of TDS, alkaline, acid, thermal and thermal alkaline pretreatments were performed. Color and aromatic amines were specifically measured as extra characteristics for the AD of TDS. The rate-limiting steps of AD of TDS were slow hydrolysis rate and inhibited acidogenesis, which were somewhat overcome by pretreatments. Thermal alkaline pretreated TDS performed best enhancement on solubilisation. The biochemical methane potential tests revealed that thermal pretreated TDS showed highest total methane production of 55.9mL/gVSfed compared to the control with little methane generation. However, thermal alkaline pretreated TDS did not perform well in BMP test as expected. Moreover, the hydrophilicity of reactive dyes in TDS could seriously affect dewaterability of TDS.

  20. Pretreatment with laccase and a phenolic mediator degrades lignin and enhances saccharification of Eucalyptus feedstock

    PubMed Central

    2014-01-01

    Background Biofuel production from lignocellulosic material is hampered by biomass recalcitrance towards enzymatic hydrolysis due to the compact architecture of the plant cell wall and the presence of lignin. The purpose of this work is to study the ability of an industrially available laccase-mediator system to modify and remove lignin during pretreatment of wood (Eucalyptus globulus) feedstock, thus improving saccharification, and to analyze the chemical modifications produced in the whole material and especially in the recalcitrant lignin moiety. Results Up to 50% lignin removal from ground eucalypt wood was attained by pretreatment with recombinant Myceliophthora thermophila laccase and methyl syringate as mediator, followed by alkaline peroxide extraction in a multistage sequence. The lignin removal directly correlated with increases (approximately 40%) in glucose and xylose yields after enzymatic hydrolysis. The pretreatment using laccase alone (without mediator) removed up to 20% of lignin from eucalypt wood. Pyrolysis-gas chromatography/mass spectrometry of the pretreated wood revealed modifications of the lignin polymer, as shown by lignin markers with shortened side chains and increased syringyl-to-guaiacyl ratio. Additional information on the chemical modifications produced was obtained by two-dimensional nuclear magnetic resonance of the whole wood swollen in dimethylsulfoxide-d6. The spectra obtained revealed the removal of guaiacyl and syringyl lignin units, although with a preferential removal of the former, and the lower number of aliphatic side-chains per phenylpropane unit (involved in main β-O-4ʹ and β-βʹ inter-unit linkages), in agreement with the pyrolysis-gas chromatography/mass spectrometry results, without a substantial change in the wood polysaccharide signals. However, the most noticeable modification observed in the spectra was the formation of Cα-oxidized syringyl lignin units during the enzymatic treatment. Further insight into

  1. Hydrogen Peroxide Concentrator

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F.

    2007-01-01

    A relatively simple and economical process and apparatus for concentrating hydrogen peroxide from aqueous solution at the point of use have been invented. The heart of the apparatus is a vessel comprising an outer shell containing tubular membranes made of a polymer that is significantly more permeable by water than by hydrogen peroxide. The aqueous solution of hydrogen peroxide to be concentrated is fed through the interstitial spaces between the tubular membranes. An initially dry sweep gas is pumped through the interiors of the tubular membranes. Water diffuses through the membranes and is carried away as water vapor mixed into the sweep gas. Because of the removal of water, the hydrogen peroxide solution flowing from the vessel at the outlet end is more concentrated than that fed into the vessel at the inlet end. The sweep gas can be air, nitrogen, or any other gas that can be conveniently supplied in dry form and does not react chemically with hydrogen peroxide.

  2. Uranyl peroxide closed clusters containing topological squares

    SciTech Connect

    Unruh, Daniel K.; Burtner, Alicia; Pressprich, Laura; Sigmon, Ginger E.; Burns, Peter C

    2010-01-01

    Four self-assembling clusters of uranyl peroxide polyhedra have been formed in alkaline aqueous solutions and structurally characterized. These clusters consist of 28, 30, 36 and 44 uranyl polyhedra and exhibit complex new topologies. Each has a structure that contains topological squares, pentagons and hexagons. Analysis of possible topologies within boundary constraints indicates a tendency for adoption of higher symmetry topologies in these cases. Small angle X-ray scattering data demonstrated that crystals of one of these clusters can be dissolved in ultrapure water and that the clusters remain intact for at least several days.

  3. Hydrogen peroxide deposition and decomposition in rain and dew waters

    NASA Astrophysics Data System (ADS)

    Ortiz, Vicky; Angélica Rubio, M.; Lissi, Eduardo A.

    Peroxides and hydrogen peroxide were determined by a fluorometric method in dew and rain collected in the atmosphere of Santiago of Chile city. The measured peroxides comprise hydrogen peroxide (the main component) and peroxides not decomposed by catalase. The collected natural peroxides readily decompose in the natural matrix, rendering difficult an estimation of the values present in real-time. In order to establish the kinetics of the process and the factors that condition their decomposition, the kinetics of the decay at several pHs and/or the presence of metal chelators were followed. The kinetics of hydrogen peroxide decomposition in the water matrix was evaluated employing the natural peroxides or hydrogen peroxide externally added. First-order kinetics was followed, with half decay times ranging from 80 to 2300 min. The addition of Fe(II) in the micromolar range increases the decomposition rate, while lowering the pH (<3) notably reduces the rate of the process. The contribution of metals to the decomposition of the peroxides in the natural waters was confirmed by the reduction in decomposition rate elicited by its treatment with Chelex-100. Dew and rain waters were collected in pre-acidified collectors, rendering values considerably higher than those measured in non-treated collectors. This indicates that acidification can be proposed as an easy procedure to stabilize the samples, reducing its decomposition during collection time and the time elapsed between collection and analysis. The weighted average concentration for total peroxides measured in pre-treated collectors was 5.4 μM in rains and 2.2 μM in dews.

  4. Anodes for alkaline electrolysis

    DOEpatents

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  5. Comprehensive utilization of glycerol from sugarcane bagasse pretreatment to fermentation.

    PubMed

    Jiang, Liqun; Zheng, Anqing; Zhao, Zengli; He, Fang; Li, Haibin

    2015-11-01

    In this study, the effects of glycerol pretreatment on subsequent glycerol fermentation and biomass fast pyrolysis were investigated. The liquid fraction from the pretreatment process was evaluated to be feasible for fermentation by Paenibacillus polymyxa and could be an economic substrate. The pretreated biomass was further utilized to obtain levoglucosan by fast pyrolysis. The pretreated sugarcane bagasse exhibited significantly higher levoglucosan yield (47.70%) than that of un-pretreated sample (11.25%). The promotion could likely be attributed to the effective removal of alkali and alkaline earth metals by glycerol pretreatment. This research developed an economically viable manufacturing paradigm to utilize glycerol comprehensively and enhance the formation of levoglucosan effectively from lignocellulose.

  6. The impacts of pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid pretreatment

    PubMed Central

    2009-01-01

    Background Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX) and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. Results Comparative evaluation on these two pretreatments reveal that (i) AFEX-pretreated corn stover is significantly more fermentable with respect to cell growth and sugar consumption, (ii) both pretreatments can achieve more than 80% of total sugar yield in the enzymatic hydrolysis of washed pretreated solids, and (iii) while AFEX completely preserves plant carbohydrates, dilute acid pretreatment at 5% solids loading degrades 13% of xylose to byproducts. Conclusion The selection of pretreatment will determine the biomass-processing configuration, requirements for hydrolysate conditioning (if any) and fermentation strategy. Through dilute acid pretreatment, the need for hemicellulase in biomass processing is negligible. AFEX-centered cellulosic technology can alleviate fermentation costs through reducing inoculum size and practically eliminating nutrient costs during bioconversion. However, AFEX requires supplemental xylanases as well as cellulase activity. As for long-term sustainability, AFEX has greater potential to diversify products from a cellulosic biorefinery due to lower levels of inhibitor generation and lignin loss. PMID:19961578

  7. Stability of a Lipase Extracted from Seeds of Pachira aquatica in Commercial Detergents and Application Tests in Poultry Wastewater Pretreatment and Fat Particle Hydrolysis

    PubMed Central

    Polizelli, Patrícia Peres; Facchini, Fernanda Dell Antonio

    2013-01-01

    A protein extract containing a plant lipase from oleaginous seeds of Pachira aquatica was tested using soybean oil, wastewater from a poultry processing plant, and beef fat particles as substrate. The hydrolysis experiments were carried out at a temperature of 40°C, an incubation time of 90 minutes, and pH 8.0-9.0. The enzyme had the best stability at pH 9.0 and showed good stability in the alkaline range. It was found that P. aquatica lipase was stable in the presence of some commercial laundry detergent formulations, and it retained full activity up to 0.35% in hydrogen peroxide, despite losing activity at higher concentrations. Concerning wastewater, the lipase increased free fatty acids release by 7.4 times and promoted the hydrolysis of approximately 10% of the fats, suggesting that it could be included in a pretreatment stage, especially for vegetable oil degradation. PMID:24455209

  8. Pretreatment Technology Plan

    SciTech Connect

    Barker, S.A.; Thornhill, C.K.; Holton, L.K. Jr.

    1993-03-01

    This technology plan presents a strategy for the identification, evaluation, and development of technologies for the pretreatment of radioactive wastes stored in underground storage tanks at the Hanford Site. This strategy includes deployment of facilities and process development schedules to support the other program elements. This document also presents schedule information for alternative pretreatment systems: (1) the reference pretreatment technology development system, (2) an enhanced pretreatment technology development system, and (3) alternative pretreatment technology development systems.

  9. Alkaline battery operational methodology

    DOEpatents

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  10. Peroxide detoxification by brain cells.

    PubMed

    Dringen, Ralf; Pawlowski, Petra G; Hirrlinger, Johannes

    Peroxides are generated continuously in cells that consume oxygen. Among the different peroxides, hydrogen peroxide is the molecule that is formed in highest quantities. In addition, organic hydroperoxides are synthesized as products of cellular metabolism. Generation and disposal of peroxides is a very important process in the human brain, because cells of this organ consume 20% of the oxygen used by the body. To prevent cellular accumulation of peroxides and damage generated by peroxide-derived radicals, brain cells contain efficient antioxidative defense mechanisms that dispose of peroxides and protect against oxidative damage. Cultured brain cells have been used frequently to investigate peroxide metabolism of neural cells. Efficient disposal of exogenous hydrogen peroxide was found for cultured astrocytes, oligodendrocytes, microglial cells, and neurons. Comparison of specific peroxide clearance rates revealed that cultured oligodendrocytes dispose of the peroxide quicker than the other neural cell cultures. Both catalase and the glutathione system contribute to the clearance of hydrogen peroxide by brain cells. For efficient glutathione-dependent reduction of peroxides, neural cells contain glutathione in high concentration and have substantial activity of glutathione peroxidase, glutathione reductase, and enzymes that supply the NADPH required for the glutathione reductase reaction. This article gives an overview on the mechanisms involved in peroxide detoxification in brain cells and on the capacity of the different types of neural cells to dispose of peroxides.

  11. The Peroxide Pathway

    NASA Technical Reports Server (NTRS)

    McNeal, Curtis I., Jr.; Anderson, William

    1999-01-01

    NASA's current focus on technology roadmaps as a tool for guiding investment decisions leads naturally to a discussion of NASA's roadmap for peroxide propulsion system development. NASA's new Second Generation Space Transportation System roadmap calls for an integrated Reusable Upper-Stage (RUS) engine technology demonstration in the FY03/FY04 time period. Preceding this integrated demonstration are several years of component developments and subsystem technology demonstrations. NASA and the Air Force took the first steps at developing focused upper stage technologies with the initiation of the Upper Stage Flight Experiment with Orbital Sciences in December 1997. A review of this program's peroxide propulsion development is a useful first step in establishing the peroxide propulsion pathway that could lead to a RUS demonstration in 2004.

  12. Hydrogen peroxide catalytic decomposition

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2010-01-01

    Nitric oxide in a gaseous stream is converted to nitrogen dioxide using oxidizing species generated through the use of concentrated hydrogen peroxide fed as a monopropellant into a catalyzed thruster assembly. The hydrogen peroxide is preferably stored at stable concentration levels, i.e., approximately 50%-70% by volume, and may be increased in concentration in a continuous process preceding decomposition in the thruster assembly. The exhaust of the thruster assembly, rich in hydroxyl and/or hydroperoxy radicals, may be fed into a stream containing oxidizable components, such as nitric oxide, to facilitate their oxidation.

  13. Triplet quenching by diacyl peroxides

    NASA Astrophysics Data System (ADS)

    Ingold, K. U.; Johnston, L. J.; Lusztyk, J.; Scaiano, J. C.

    1984-10-01

    Benzoyl and decanoyl peroxides are efficient quenchers of various triplet sensitizers: kinetic studies using laser photolysis techniques indicate that electronic energy transfer and charge transfer to the peroxide are important factors contributing to the quenching process.

  14. Priming effect of abscisic acid on alkaline stress tolerance in rice (Oryza sativa L.) seedlings.

    PubMed

    Wei, Li-Xing; Lv, Bing-Sheng; Wang, Ming-Ming; Ma, Hong-Yuan; Yang, Hao-Yu; Liu, Xiao-Long; Jiang, Chang-Jie; Liang, Zheng-Wei

    2015-05-01

    Saline-alkaline stress is characterized by high salinity and high alkalinity (high pH); alkaline stress has been shown to be the primary factor inhibiting rice seedling growth. In this study, we investigated the potential priming effect of abscisic acid (ABA) on tolerance of rice seedlings to alkaline stress simulated by Na2CO3. Seedlings were pretreated with ABA at concentrations of 0 (control), 10, and 50 μM by root-drench for 24 h and then transferred to a Na2CO3 solution that did not contain ABA. Compared to control treatment, pretreatment with ABA substantially improved the survival rate of rice seedlings and increased biomass accumulation after 7 days under the alkaline condition. ABA application at 10 μM also alleviated the inhibitory effects of alkaline stress on the total root length and root surface area. Physiologically, ABA increased relative water content (RWC) and decreased cell membrane injury degree (MI) and Na(+)/K(+) ratios. In contrast, fluridone (an ABA biosynthesis inhibitor) decreased the RWC and increased MI in shoots under the alkaline conditions. These data suggest that ABA has a potent priming effect on the adaptive response to alkaline stress in rice and may be useful for improving rice growth in saline-alkaline paddy fields.

  15. Hydrogen peroxide and organic peroxides in the marine environment

    NASA Astrophysics Data System (ADS)

    Heikes, Brian G.; Miller, William L.; Lee, Meehye

    1991-05-01

    Aqueous fluorescence and chemiluminescence methods have been used to measure hydrogen peroxide in natural waters and in the atmosphere. Ambient hydrogen peroxide and soluble organic peroxide data is presented from the EMEX, MLOPEX and SAGA-3 experimental programs, experiments conducted in the remote marine environment. Methods to measure organic peroxide using conventional collection strategies and direct analysis by chemiluminescence or fluorescence method is approximately two orders of magnitude more sensitive than the fluorescence method. Species specific measurements of organic peroxides are also in development using high pressure liquid chromatography (HPLC) and fluorescence or chemiluminescence detection.

  16. Alkaline flooding injection strategy

    SciTech Connect

    French, T.R.; Josephson, C.B.

    1992-03-01

    The objective of this project is to improved alkali-surfactant flooding methods, and this includes determining the proper design of injection strategy. Several different injection strategies have been used or suggested for recovering heavy oils with surfactant-enhanced alkaline flooding methods. Oil recovery was compared for four different injection strategies: (1) surfactant followed by polymer, (2) surfactant followed by alkaline polymer, (3) alkaline surfactant followed by polymer, and (4) alkali, surfactant, and polymer mixed in a single formulation. The effect of alkaline preflush was also studied under two different conditions. All of the oil recovery experiments were conducted under optimal conditions with a viscous, non-acidic oil from Hepler (KS) oil field. The coreflood experiments were conducted with Berea sandstone cores since field core was not available in sufficient quantity for coreflood tests. The Tucker sand of Hepler field is a Class I fluvial dominated deltaic reservoir, as classified by the Department of Energy, which has been selected as the site of a DOE-sponsored field pilot test.

  17. Simultaneous saccharification and cofermentation of peracetic acid-pretreated biomass.

    PubMed

    Teixeira, L C; Linden, J C; Schroeder, H A

    2000-01-01

    Previous work in our laboratories has demonstrated the effectiveness of peracetic acid for improving enzymatic digestibility of lignocellulosic materials. The use of dilute alkali solutions as a pre-pretreatment prior to peracetic acid lignin oxidation increased carbohydrate hydrolysis yields in a synergistic as opposed to additive manner. Deacetylation of xylan is easily achieved using dilute alkali solutions under mild conditions. In this article, we evaluate the effectiveness of peracetic acid combined with an alkaline pre-pretreatment through simultaneous saccharification and cofermentation (SSCF) of pretreated hybrid poplar wood and sugar cane bagasse. Respective ethanol yields of 92.8 and 91.9% of theoretical are achieved using 6% NaOH/15% peracetic acid-pretreated substrates and recombinant Zymomonas mobilis CP4/pZB5. Reduction of acetyl groups of the lignocellulosic materials is demonstrated following alkaline pre-pretreatments. Such processing may be helpful in reducing peracetic acid requirements. The influence of deacetylation is more significant in combined pretreatments using lower peracetic acid loadings.

  18. Protein oxidation and peroxidation

    PubMed Central

    Davies, Michael J.

    2016-01-01

    Proteins are major targets for radicals and two-electron oxidants in biological systems due to their abundance and high rate constants for reaction. With highly reactive radicals damage occurs at multiple side-chain and backbone sites. Less reactive species show greater selectivity with regard to the residues targeted and their spatial location. Modification can result in increased side-chain hydrophilicity, side-chain and backbone fragmentation, aggregation via covalent cross-linking or hydrophobic interactions, protein unfolding and altered conformation, altered interactions with biological partners and modified turnover. In the presence of O2, high yields of peroxyl radicals and peroxides (protein peroxidation) are formed; the latter account for up to 70% of the initial oxidant flux. Protein peroxides can oxidize both proteins and other targets. One-electron reduction results in additional radicals and chain reactions with alcohols and carbonyls as major products; the latter are commonly used markers of protein damage. Direct oxidation of cysteine (and less commonly) methionine residues is a major reaction; this is typically faster than with H2O2, and results in altered protein activity and function. Unlike H2O2, which is rapidly removed by protective enzymes, protein peroxides are only slowly removed, and catabolism is a major fate. Although turnover of modified proteins by proteasomal and lysosomal enzymes, and other proteases (e.g. mitochondrial Lon), can be efficient, protein hydroperoxides inhibit these pathways and this may contribute to the accumulation of modified proteins in cells. Available evidence supports an association between protein oxidation and multiple human pathologies, but whether this link is causal remains to be established. PMID:27026395

  19. Investigation on regeneration of basic hydrogen peroxide by electrochemical methods

    NASA Astrophysics Data System (ADS)

    Ke, Changchun; Chen, Wenwu; Xu, Xiaobo; Wang, Jinglong; Liu, Yushi; Jin, Yuqi; Sang, Fengting

    2015-02-01

    Two electrochemical methods for regeneration of Basic Hydrogen Peroxide (BHP) were investigated in this paper, which could be called one-step method and two-step method, respectively, distinguished by the number of steps during the regeneration process. The one-step method converts potassium chloride solution and oxygen directly to chlorine and BHP by a modified chlor-alkali cell with an oxygen cathode. For the one-step method, two reactors of different structure and corresponding regenerating process were designed. The experimental results showed that, for the continuous-type reactor, the highest peroxide concentration was 0.042 mol/L, while for batch-type reactor the highest peroxide concentration was 0.563 mol/L. The two-step method accomplishes the regeneration of BHP by a conventional chlor-alkali cell combined with a fuel cell reactor which could convert hydrogen and oxygen to peroxide in alkaline potassium hydroxide solution. A peroxide concentration of 2.450 mol/L was obtained for the two-step method.

  20. Micellar electrokinetic chromatography of organic and peroxide-based explosives.

    PubMed

    Johns, Cameron; Hutchinson, Joseph P; Guijt, Rosanne M; Hilder, Emily F; Haddad, Paul R; Macka, Mirek; Nesterenko, Pavel N; Gaudry, Adam J; Dicinoski, Greg W; Breadmore, Michael C

    2015-05-30

    CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of sample composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25 mM sodium tetraborate, 75 mM sodium dodecyl sulfate at 25°C, detection at 200 nm) were applied to the separation of 25 organic explosives in 17 min, with very high efficiency (typically greater than 300,000 plates m(-1)) and high sensitivity (LOD typically less than 0.5 mg L(-1); around 1-1.5 μM). A MEKC method was also developed for peroxide-based explosives (10 mM sodium tetraborate, 100 mM sodium dodecyl sulfate at 25°C, detection at 200 nm). UV detection provided LODs between 5.5 and 45.0 mg L(-1) (or 31.2-304 μM), which is comparable to results achieved using liquid chromatography. Importantly, no sample pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices.

  1. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

  2. Advanced alkaline water electrolysis

    NASA Astrophysics Data System (ADS)

    Wakabayashi, N.; Torikai, E.; Kawami, Y.; Takenaka, H.

    Results are presented of experimental studies of possible separators and electrodes for use in advanced, high-temperature, high-pressure alkaline water electrolyzers. Material evaluations in alkaline water electrolyzers at temperatures from 100 to 120 C have shown a new type polytetrafluoroethylene membrane impregnated with potassium titanate to be the most promising when the separator is prepared by the hydrothermal treatment of a porous PFTE membrane impregnated with hydrated titanium oxide. Measurements of cell voltages in 30% KOH at current densities from 5 to 100 A/sq dm at temperatures up to 120 C with nickel electrodes of various structures have shown the foamed nickel electrode, with an average pore size of 1-1.5 mm, to have the best performance. When the foamed nickel is coated by fine powdered nickel, carbonyl nickel or Raney nickel to increase electrode surface areas, even lower cell voltages were found, indicating better performance.

  3. Electrodeposited nanostructured MnO{sub 2} for non-enzymatic hydrogen peroxide sensing

    SciTech Connect

    Saha, B. Jana, S. K.; Banerjee, S.

    2015-06-24

    Electrodeposited MnO{sub 2} nanostructure was synthesized on indium tin oxide coated glass electrode by cyclic voltammetry. The as obtained samples were subsequently characterized by atomic force microscopy and their electro-catalytic response towards hydrogen peroxide in alkaline medium of 0.1M NaOH was studied using cyclic voltammetry and amperometry.

  4. Net alkalinity and net acidity 2: Practical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH < 6.3 after oxidation had positive Hot Acidity. Samples with similar pH values before oxidation had dissimilar Hot Acidities due to variations in their alkalinities and dissolved Fe, Mn, and Al concentrations. Hot Acidity was approximately equal to net acidity calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the

  5. Bioflocculant from pre-treated sludge and its applications in sludge dewatering and swine wastewater pretreatment.

    PubMed

    Guo, Junyuan; Ma, Jing

    2015-11-01

    Potentials of alkaline-thermal (ALT) pre-treated sludge as a bioflocculant were studied in sludge dewatering and swine wastewater pretreatment. When incubated with this ALT pre-treated sludge, dry solids (DS) and specific resistance to filtration (SRF) of typical wastewater activated sludge reached 22.5% and 3.4×10(12)m/kg, respectively, which were much better than that obtained with conventional chemical flocculants. Sludge dewatering was further improved when both the bioflocculant and conventional polyaluminum chloride (PAC) were used simultaneously. Charge neutralization and inter-particle bridging were proposed as the reasons for the enhanced performance in the case of the combined use. With swine wastewater, the bioflocculant could remove COD, ammonium and turbidity by 45.2%, 41.8% and 74.6% when incubated with 20mg/L at pH 8.0. This study suggested that the ALT pre-treated sludge has a great potential as an alternative bioflocculant to conventional flocculants in sludge dewatering and swine wastewater pretreatment.

  6. Tested Demonstrations. The Stepwise Reduction of Permanganate in Alkaline Conditions: A Lecture Demonstration.

    ERIC Educational Resources Information Center

    Ruoff, Peter; Riley, Megan

    1987-01-01

    Describes a chemistry experiment where an alkaline ice-cold permanganate solution is reduced by adding dropwise a cold diluted hydrogen peroxide solution. Outlines the course of the reduction through the various oxidation states of manganese with their characteristic colors. (TW)

  7. 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.

  8. 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.

  9. Oxidative stress-induced apoptotic insults to rat osteoblasts are attenuated by nitric oxide pretreatment via GATA-5-involved regulation of Bcl-X L gene expression and protein translocation.

    PubMed

    Wu, Gong-Jhe; Wang, Weu; Lin, Yi-Ling; Liu, Shing Hwa; Chen, Ruei-Ming

    2016-04-01

    Nitric oxide (NO) has biphasic effects on regulating osteoblast survival and death. This study was aimed to evaluate the effects of NO pretreatment on hydrogen peroxide (HP)-induced insults of rat osteoblasts and the possible mechanisms. Exposure of osteoblasts prepared from rat calvarias to HP significantly increased intracellular reactive oxygen species levels, decreased alkaline phosphatase activity and cell survival, and ultimately induced cell apoptosis. However, NO pretreatment lowered HP-induced oxidative stress and apoptotic insults. In parallel, HP increased Bax levels and its translocation from the cytoplasm to mitochondria. NO pretreatment caused significant attenuations in HP-induced modulations in Bax synthesis and translocation. In contrast, pretreatment with NO enhanced levels and translocation of antiapoptotic Bcl-XL protein in rat osteoblasts. RNA analyses further revealed that HP inhibited Bcl-XL mRNA expression without affecting Bax mRNA levels. In comparison, NO induced Bcl-XL mRNA production and alleviated HP-caused inhibition of this mRNA expression. As to the mechanism, HP suppressed RNA and protein levels of transcription factor GATA-5 in rat osteoblasts. Pretreatment with NO induced GATA-5 mRNA and protein expressions and simultaneously attenuated HP-induced inhibition of this gene's expression. Consequently, GATA-5 knockdown using RNA interference inhibited Bcl-XL mRNA expression and concurrently lowered NO's protection against HP-induced apoptotic insults. Therefore, this study showed that NO can protect rat osteoblasts from HP-induced apoptotic insults. The protective mechanisms are mediated by GATA-5-mediated transcriptional induction of Bcl-X L gene, and translocational modulation of Bcl-XL and Bax proteins.

  10. Comparative study of low-energy ultrasonic and alkaline treatment on biosludge from secondary industrial wastewater treatment.

    PubMed

    Li, Dongzhe; Tan, Youming; Zhou, Yan; Pathak, Santosh; Sendjaja, Antonius Yudi; Abdul Majid, Maszenan; Chowdhury, Prannoy; Ng, Wun Jern

    2015-01-01

    In this study, low-energy ultrasonic (3 and 6 kJ/g volatile solids of feed biomass (FB) which was lower than the heat value of the FB), alkaline, and ultrasonic-alkaline pretreatments were applied on FB, a biosludge from secondary industrial wastewater treatment. Biochemical methane potential (BMP), particle size distribution, Biomass Stress Index (BSI™), soluble chemical oxygen demand (SCOD), protein, carbohydrate, and size-exclusion chromatography (SEC) fingerprints were used to comparatively study the mechanisms of these pretreatment methods. The results indicated that low-energy ultrasonication and alkali exhibited significantly different impacts on the FB. After ultrasonication with energy input of 6 kJ/g-VS, the average particle size of FB was reduced from 102.6 to 19.4 µm. However, ultrasonication had no obvious effect on microbial cells rupture, solubilization of protein and carbohydrate, and SEC fingerprint. Consequently, low-energy ultrasonication could not enhance methane generation. However, after alkaline pretreatment with dosage of 0.3 g-NaOH/g-VS, SCOD, soluble protein, and soluble carbohydrate concentration of FB increased from 0.66, 0.00, 0.07 to 2.83, 0.83, 0.47 g/L, respectively. At the same time, BSI™ increased from 5.3% to 96.8%, and the SEC fingerprint changed significantly. Consequently, the methane generation in the BMP test increased from 68.9 to 135.0 mL. Ultrasonic-alkaline pretreatment was similar to alkaline pretreatment in terms of methane generation. Based on this study, alkaline pretreatment is recommended over both low-energy ultrasonic and low-energy ultrasonic-alkaline pretreatment to enhance the biodegradability of FB.

  11. Net alkalinity and net acidity 1: Theoretical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    standard method "hot peroxide" acidity titration, provided that labs report negative values. The authors recommend the third approach; i.e., net alkalinity = -Hot Acidity. ?? 2005 Elsevier Ltd. All rights reserved.

  12. Treatment of ammonia contaminated water by ozone and hydrogen peroxide

    SciTech Connect

    Yuan, F.; Hill, D.O.; Kuo, C.H.

    1995-12-31

    The present research concerns kinetics of oxidation of ammonia by ozone and ozone-hydrogen peroxide mixtures in alkaline solutions. Experiments were carried out at 15 to 35{degrees}C in solutions with pH values varying from 8 to 10 utilizing a stopped-flow spectrophotometer system. Fractions of free ammonia present in acidic and neutral solutions are negligible, and the reaction is very slow. This confirms that only free ammonia can react with ozone in the aqueous phase. The reaction proceeds at moderate rates in the alkaline solutions requiring four moles of ozone to react with each mole of ammonia. The free ammonia is oxidized and converted completely to nitrate in the solutions. The overall reaction between ammonia and ozone is second order with first order in each reactant. The reaction rate constant increases with temperature and pH value of the solution. The average activation energy is 59 Kcal/gmol for all systems investigated at different pH values. The results of the kinetic experiments suggest that the reaction is predominated by the direct oxidation between ammonia and ozone molecules, and that the hydroxyl radical reactions play insignificant roles in the ozonation process. The oxidation rate of ammonia is enhanced considerably in the presence of hydrogen peroxide and ozone mixtures. The formation of hydroxyl radical from interactions between ozone and hydrogen peroxide and the subsequent free radical reactions of ammonia seem important in controlling the destruction rate of free ammonia, as suggested by the results of this study.

  13. Effect of pretreatment of salt, copper and temperature on ultraviolet-B-induced antioxidants in diazotrophic cyanobacterium Anabaena doliolum.

    PubMed

    Srivastava, Ashish Kumar; Bhargava, Poonam; Mishra, Yogesh; Shukla, Bideh; Rai, Lal Chand

    2006-01-01

    Effect of salt, copper, and temperature pretreatments on the UV-B-induced oxidative damage, measured in terms of peroxide and MDA (lipid peroxidation) contents, was studied in the diazotrophic cyanobacterium Anabaena doliolum. To understand the survival strategy enzymatic (superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase) and non-enzymatic (glutathione, ascorbate, alpha-tocopherol and carotenoid) antioxidants were studied. Among the various pretreatments salt was found to decrease and copper and temperature pretreatments increased the deleterious effects of UV-B. This study is the first to demonstrate that physical stress (high temperature) enhanced the damaging effect of UV-B more profoundly than chemical stresses (salt and copper).

  14. Some anion-transport properties of Nafion™ 117 from fuel cell hydrogen peroxide generation data

    NASA Astrophysics Data System (ADS)

    Piela, Piotr; Wrona, Piotr K.

    Hydrogen peroxide generation R&D data obtained in an alkaline fuel cell-type electrochemical reactor with a dividing Nafion™ 117 membrane have been used to extract anion-conducting properties of the cation-exchange membrane. The effective diffusion coefficient of NaOH and the average transport number of OH - in the membrane were obtained by fitting a model formula for the total alkalinity of outlet catholyte to experimental alkalinities obtained with various electrolysis parameters' values. The formula resulted from assumptions that NaOH diffuses through the membrane and OH - migrates through the membrane, and that HO 2 - does not penetrate the membrane. The membrane parameters extracted in this way were in good agreement with similar data reported by others for Nafion™. Hydrogen peroxide current efficiencies remained over 90% and H 2O 2 concentrations reached 7 wt.%, however the fuel cell reactor's electrical efficiency was strongly limited by high internal resistance.

  15. Optimization of hydrogen peroxide in totally chlorine free bleaching of cellulose pulp from olive tree residues.

    PubMed

    López, F; Díaz, M J; Eugenio, M E; Ariza, J; Rodríguez, A; Jiménez, L

    2003-05-01

    The influence of the operating conditions used in the bleaching of olive wood trimmings pulp (viz. hydrogen peroxide concentration and time) on the yield, kappa index and viscosity of the resulting pulp and on strength-related properties of paper sheets was studied to determine the optimal bleaching conditions of this pulp. Hydrogen peroxide bleached pulps at different sequences (oxygen, ozone, chlorine dioxide and alkaline extractions) were compared. Hydrogen peroxide bleaching proved to be suitable for this pulp. Considerable improvements in viscosity were obtained with respect to other bleaching sequences such as oxygen, ozone and chlorine dioxide. Hydrogen peroxide bleaching decreased the kappa index 51.3% less than ozone bleaching, 25.0% less than chlorine dioxide (D) and 6.3% less combined chlorine dioxide-alkaline extraction (DE). To obtain kappa indices 50.9% and 37.9% lower than the index achieved by hydrogen peroxide, oxygen (LaO(p)) and ozone (LaO(LaZ)R) sequences respectively were needed. Lower-medium levels of hydrogen peroxide concentrations (1-3%) and high reaction times (210 min) proved to be suitable for bleaching of pulp olive trimming residues. This approach could be used on this residue to produce adequately bleached pulp.

  16. Pretreatment combining ultrasound and sodium percarbonate under mild conditions for efficient degradation of corn stover.

    PubMed

    Nakashima, Kazunori; Ebi, Yuuki; Kubo, Masaki; Shibasaki-Kitakawa, Naomi; Yonemoto, Toshikuni

    2016-03-01

    Ultrasound (US) can be used to disrupt microcrystalline cellulose to give nanofibers via ultrasonic cavitation. Sodium percarbonate (SP), consisting of sodium carbonate and hydrogen peroxide, generates highly reactive radicals, which cause oxidative delignification. Here, we describe a novel pretreatment technique using a combination of US and SP (US-SP) for the efficient saccharification of cellulose and hemicellulose in lignocellulosic corn stover. Although US-SP pretreatment was conducted under mild condition (i.e., at room temperature and atmospheric pressure), the pretreatment greatly increased lignin removal and cellulose digestibility. We also determined the optimum US-SP treatment conditions, such as ultrasonic power output, pretreatment time, pretreatment temperature, and SP concentration for an efficient cellulose saccharification. Moreover, xylose could be effectively recovered from US-SP pretreated biomass without the formation of microbial inhibitor furfural.

  17. Influence of cysteine and methionine availability on protein peroxide scavenging activity and phenolic stability in emulsions.

    PubMed

    Zhou, Lisa; Elias, Ryan J

    2014-03-01

    Plant phenolics are secondary metabolites that have been shown to confer beneficial health effects in humans. However, many of these compounds undergo metal-catalysed oxidation reactions, leading to the generation of hydrogen peroxide (H2O2) and other reactive oxygen species that may negatively impact product stability. In proteins, methionine (Met) and cysteine (Cys) are capable of reacting directly with peroxides. Thus, the dairy proteins, casein (CAS) and β-lactoglobulin (BLG), were examined for their ability to scavenge H2O2 (400μM) and influence (-)-epigallocatechin-3-gallate (EGCG) oxidation (400μM) in Tween- or sodium dodecyl sulphate (SDS)-stabilised hexadecane emulsions. To examine the effect that the accessibility of these amino acids have on their peroxide scavenging activities, proteins were pre-treated with tert-butyl hydroperoxide (TBHP), a bulky peroxide, to oxidise only solvent accessible Met residues or H2O2, the smallest peroxide, to oxidise buried Met residues. In CAS treatments, higher Met content yielded greater peroxide scavenging activity and EGCG stability. CAS treatments also showed significantly higher peroxide scavenging activity compared to the corresponding BLG treatment. However, BLG peroxide scavenging activity was greatly enhanced in SDS-stabilised emulsions due to protein denaturation and subsequent exposure of previously buried Cys residues.

  18. Diffusion of peroxides through dentine in vitro with and without prior use of a desensitizing varnish.

    PubMed

    Hannig, Christian; Weinhold, Hans Christian; Becker, Klaus; Attin, Thomas

    2011-12-01

    Different bleaching regimens are used in dentistry possibly penetrating the dentine and affecting the pulp. The aim of the present study was to investigate peroxide diffusion through dentine pre-treated with a desensitizing varnish (Vivasens®) in a standardized in vitro setup during application of different bleaching materials. The penetration was tested using 1.3-mm-thick bovine dentine slabs. The following bleaching materials were tested with and without prior application of the desensitizing varnish on the external side of the dentine slabs: Vivastyle, Whitestrips, Simply White, Opalescence (external bleaching), and sodium perborate (internal bleaching, only tested without varnish; n = 8 samples per subgroup). The penetration of peroxides was measured photometrically using 4-aminoantipyrin as a substrate, the penetration of peroxides was monitored over 240 min. All bleaching agents yielded a diffusion of peroxides through the dentine, the kinetics of penetration were approximately linear for all materials tested. The significantly highest diffusion of peroxides was observed with Opalescence, the lowest with sodium perborate. The adoption of the desensitizing varnish reduced the diffusion of peroxides significantly for all external bleaching materials. Peroxides penetrated the dentine during application of bleaching materials; the penetration of peroxides can be reduced by application of a desensitizing agent.

  19. Role of hydrogen peroxide and hydroxyl radical in pyrite oxidation by molecular oxygen

    NASA Astrophysics Data System (ADS)

    Schoonen, Martin A. A.; Harrington, Andrea D.; Laffers, Richard; Strongin, Daniel R.

    2010-09-01

    Hydrogen peroxide and hydroxyl radical are readily formed during the oxidation of pyrite with molecular oxygen over a wide range of pH conditions. However, pretreatment of the pyrite surface influences how much of the intermediates are formed and their fate. Acid-washed pyrite produces significant amounts of hydrogen peroxide and hydroxyl radical when suspended in air-saturated water. However, the hydrogen peroxide concentration shows an exponential decrease with time. Suspensions made with partially oxidized pyrite yield significantly lower amounts of hydrogen peroxide product. The presence of Fe(III)-oxide or Fe(III)-hydroxide patches facilitates the conversion of hydrogen peroxide to oxygen and water. Hence, the degree to which a pyrite surface is covered with patches of Fe(III)-oxide or Fe(III)-hydroxide patches is an important control on the concentration of hydrogen peroxide in solution. Hydrogen peroxide appears to be an important intermediate in the four-electron transfer from pyrite to molecular oxygen. Addition of catalase, an enzyme that decomposes hydrogen peroxide to water and molecular oxygen, to a pyrite suspension reduces the oxidation rate by 40%. By contrast, hydroxyl radical does not appear to play a significant role in the oxidation mechanism. It is estimated on the basis of a molecular oxygen and sulfate mass balance that 5-6% of the molecular oxygen is consumed without forming sulfate.

  20. 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.

  1. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes

    NASA Astrophysics Data System (ADS)

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  2. Hydrogen peroxide as a new defensive compound in "benzoyl cyanide" producing polydesmid millipedes.

    PubMed

    Kuwahara, Yasumasa; Yamaguchi, Takuya; Ichiki, Yayoi; Tanabe, Tsutomu; Asano, Yasuhisa

    2017-04-01

    Hydrogen peroxide was newly and simultaneously demonstrated with well-known hydrogen cyanide as a component of defensive secretions of "benzoyl cyanide" producing polydesmid millipedes. Presence of hydrogen peroxide was successively evidenced by Trinder reagent's spray with colorless as well as oily smears of defensive secretions containing benzoyl cyanide and hydrogen cyanide by alkaline picrate paper treatment. Linear correlation was demonstrated between quantities of hydrogen peroxide and benzoyl cyanide. By qualitative assay, seven benzoyl cyanide containing polydesmidans (six species of adults and one species of a nymph at stadium I) tested positive to Trinder reagent, indicative of the presence of hydrogen peroxide (together with hydrogen cyanide), while two cyanogenic species without benzoyl cyanide exhibited negative responses to the reagent. Two types of millipedes were elucidated as species of cyanogenic Polydesmida.

  3. Peroxidation of polyunsaturated fatty acids by lipoxygenases drives ferroptosis

    PubMed Central

    Yang, Wan Seok; Kim, Katherine J.; Gaschler, Michael M.; Patel, Milesh; Shchepinov, Mikhail S.

    2016-01-01

    Ferroptosis is form of regulated nonapoptotic cell death that is involved in diverse disease contexts. Small molecules that inhibit glutathione peroxidase 4 (GPX4), a phospholipid peroxidase, cause lethal accumulation of lipid peroxides and induce ferroptotic cell death. Although ferroptosis has been suggested to involve accumulation of reactive oxygen species (ROS) in lipid environments, the mediators and substrates of ROS generation and the pharmacological mechanism of GPX4 inhibition that generates ROS in lipid environments are unknown. We report here the mechanism of lipid peroxidation during ferroptosis, which involves phosphorylase kinase G2 (PHKG2) regulation of iron availability to lipoxygenase enzymes, which in turn drive ferroptosis through peroxidation of polyunsaturated fatty acids (PUFAs) at the bis-allylic position; indeed, pretreating cells with PUFAs containing the heavy hydrogen isotope deuterium at the site of peroxidation (D-PUFA) prevented PUFA oxidation and blocked ferroptosis. We further found that ferroptosis inducers inhibit GPX4 by covalently targeting the active site selenocysteine, leading to accumulation of PUFA hydroperoxides. In summary, we found that PUFA oxidation by lipoxygenases via a PHKG2-dependent iron pool is necessary for ferroptosis and that the covalent inhibition of the catalytic selenocysteine in Gpx4 prevents elimination of PUFA hydroperoxides; these findings suggest new strategies for controlling ferroptosis in diverse contexts. PMID:27506793

  4. Peroxidation of polyunsaturated fatty acids by lipoxygenases drives ferroptosis.

    PubMed

    Yang, Wan Seok; Kim, Katherine J; Gaschler, Michael M; Patel, Milesh; Shchepinov, Mikhail S; Stockwell, Brent R

    2016-08-23

    Ferroptosis is form of regulated nonapoptotic cell death that is involved in diverse disease contexts. Small molecules that inhibit glutathione peroxidase 4 (GPX4), a phospholipid peroxidase, cause lethal accumulation of lipid peroxides and induce ferroptotic cell death. Although ferroptosis has been suggested to involve accumulation of reactive oxygen species (ROS) in lipid environments, the mediators and substrates of ROS generation and the pharmacological mechanism of GPX4 inhibition that generates ROS in lipid environments are unknown. We report here the mechanism of lipid peroxidation during ferroptosis, which involves phosphorylase kinase G2 (PHKG2) regulation of iron availability to lipoxygenase enzymes, which in turn drive ferroptosis through peroxidation of polyunsaturated fatty acids (PUFAs) at the bis-allylic position; indeed, pretreating cells with PUFAs containing the heavy hydrogen isotope deuterium at the site of peroxidation (D-PUFA) prevented PUFA oxidation and blocked ferroptosis. We further found that ferroptosis inducers inhibit GPX4 by covalently targeting the active site selenocysteine, leading to accumulation of PUFA hydroperoxides. In summary, we found that PUFA oxidation by lipoxygenases via a PHKG2-dependent iron pool is necessary for ferroptosis and that the covalent inhibition of the catalytic selenocysteine in Gpx4 prevents elimination of PUFA hydroperoxides; these findings suggest new strategies for controlling ferroptosis in diverse contexts.

  5. Thermo-chemical pretreatment and enzymatic hydrolysis for enhancing saccharification of catalpa sawdust.

    PubMed

    Jin, Shuguang; Zhang, Guangming; Zhang, Panyue; Li, Fan; Fan, Shiyang; Li, Juan

    2016-04-01

    To improve the reducing sugar production from catalpa sawdust, thermo-chemical pretreatments were examined and the chemicals used including NaOH, Ca(OH)2, H2SO4, and HCl. The hemicellulose solubilization and cellulose crystallinity index (CrI) were significantly increased after thermo-alkaline pretreatments, and the thermo-Ca(OH)2 pretreatment showed the best improvement for reducing sugar production comparing to other three pretreatments. The conditions of thermo-Ca(OH)2 pretreatment and enzymatic hydrolysis were systematically optimized. Under the optimal conditions, the reducing sugar yield increased by 1185.7% comparing to the control. This study indicates that the thermo-Ca(OH)2 pretreatment is ideal for the saccharification of catalpa sawdust and that catalpa sawdust is a promising raw material for biofuel.

  6. Lipid peroxidation, hemolysis and antioxidant enzymes of erythrocytes in stroke.

    PubMed

    Sudha, K; Rao, Ashalatha V; Rao, Suryanarayana; Rao, Anjali

    2004-04-01

    Erythrocyte membrane lipid peroxidation and consequent percentage hemolysis and related antioxidant enzymes viz., superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase were determined in 16 cases of hemorrhagic stroke and 30 cases of thrombotic stroke. The results obtained were compared with 50 age and sex matched controls. 12 thrombotic stroke patients who showed symptomatic recovery after medication were considered for follow up. Lipid peroxidation and percentage hemolysis in patients with thrombotic stroke and hemorrhagic stroke was significantly elevated when compared to controls. Glutathione reductase and superoxide dismutase levels were found to be significantly reduced in thrombotic stroke and hemorrhagic stroke respectively, when compared to healthy subjects. There was no significant difference in the other parameters when compared to controls. In post treatment thrombotic stoke, catalase and glutathione reductase levels increased significantly and oxidative hemolysis decreased compared to their pretreatment values. Thus, our results indicate considerable oxidative stress in stroke.

  7. Efficient pretreatment of Vietnamese rice straw by soda and sulfate cooking methods for enzymatic saccharification.

    PubMed

    Dien, Le Quang; Phuong, Nguyen Thi Minh; Hoa, Doan Thai; Hoang, Phan Huy

    2015-02-01

    This manuscript presents a study on alkaline pretreatment of Vietnamese rice (Oryza sativa L.) straw that grows in Northern Vietnam for enzymatic saccharification. The NaOH pretreatment (soda cooking) and NaOH/Na2S pretreatment (sulfate cooking) were applied for rice straw pretreatment, which have relatively similar condition with industrial pulping processes but at lower temperature. Pretreated biomass solid was then enzymatic hydrolyzed by commercial enzyme Cellic®CTec2 (Novozymes) with enzyme dosage of 35 FPU/g to achieve reducing sugars. The suitable condition for pretreatment was found at temperature of about 100 °C, pretreatment time of 2 h, and solid/liquid ratio of 1:10 with active alkali dosage of 20 % of dry rice straw. Under this pretreatment condition, sugar yield in enzymatic hydrolysis up to 45.33 and 48.92 % over dry rice straw could be obtained after soda cooking and sulfate cooking pretreatment, respectively. Moreover, the changes of components of rice straw after pretreatment were also studied. The crystallinity of cellulose in pretreated biomass solid was calculated from XRD pattern. And the fibril morphology after treatment was revealed by the microscopic observations performed by scanning electron microscope (SEM).

  8. Protective Effects of Minor Components of Curcuminoids on Hydrogen Peroxide-Treated Human HaCaT Keratinocytes.

    PubMed

    Liu, Yuh-Hwa; Lin, Yin-Shiou; Huang, Yu-Wei; Fang, Sheng-Uei; Lin, Shyr-Yi; Hou, Wen-Chi

    2016-05-11

    Hydrogen peroxide, one of the reactive oxygen species (ROS), can cause intracellular oxidative stress associated with skin aging and/or photoaging. Curcumin, a polyphenol in turmeric, has been reported to exhibit biological activity. In this study, five naturally occurring curcuminoids [curcumin, demethoxycurcumin (DMC), bisdemethoxycurcumin (BDMC), monohydroxy-DMC, and monohydroxy-BDMC] were used to investigate their protective roles against hydrogen peroxide-induced oxidative stress in the immortalized human keratinocyte cell lines (HaCaT cells). These five curcuminoids at 10 μM, but not at 5 μM, were shown to exhibit cytotoxicities toward HaCaT keratinocytes. Therefore, a 5 μM concentration of the five curcuminoids was selected for further investigations. Cells were pretreated with or without curcuminoids for 2.5 h before 24-h hydrogen peroxide (150 μM) treatments. Pretreatments with the minor components monohydroxy-DMC or monohydroxy-BDMC, but not curcumin, DMC, and BDMC, showed protective activity, elevating cell viability compared to cells with direct hydrogen peroxide treatments. Pretreatments with monohydroxy-DMC and monohydroxy-BDMC showed the best protective effects, reducing apoptotic cell populations and intracellular ROS, as demonstrated by flow cytometry, as well as reducing the changes of the mitochondrial membrane potential compared to cells with direct hydrogen peroxide treatments. The pretreatments with monohydroxy-DMC and monohydroxy-BDMC reduced c-jun and c-fos mRNA expression and p53 tumor suppressor protein expression and increased HO-1 protein expression and glutathione peroxidase (GPx) activity, respectively, compared to cells with direct hydrogen peroxide treatments. The five curcuminoids exhibited similar hydrogen peroxide-scavenging activity in vitro. It was proposed that monohydroxy-DMC and monohydroxy-BDMC could induce antioxidant defense systems better than curcumin, DMC, or BDMC could against hydrogen peroxide-induced oxidative

  9. New prospects in pretreatment of cotton fabrics using microwave heating.

    PubMed

    Hashem, M; Taleb, M Abou; El-Shall, F N; Haggag, K

    2014-03-15

    As microwaves are known to give fast and rapid volume heating, the present study is undertaken to investigate the use of microwave heating for pretreatment cotton fabrics to reduce the pretreatment time, chemicals and water. The onset of the microwave heating technique on the physicochemical and performance properties of desized, scoured and bleached cotton fabric is elucidated and compared with those obtained on using conventional thermal heating. Combined one-step process for desizing, scouring and bleaching of cotton fabric under microwave heating was also investigated. The dual effect of adding urea, (as microwave absorber and hydrogen peroxide activator) has been exploiting to accelerate the pretreatment reaction of cotton fabric. DSC, FT-IR and SEM have been used to investigate the onset of microwave on the morphological and chemical change of cotton cellulose after pretreatment and bleaching under microwave heating. Results obtained show that, a complete fabric preparation was obtained in just 5 min on using microwave in pretreatments process and the fabric properties were comparable to those obtained in traditional pretreatment process which requires 2.5-3h for completion.

  10. Carcinogenesis studies with benzoyl peroxide (Panoxyl gel 5%)

    SciTech Connect

    Iversen, O.H.

    1986-04-01

    Several groups of hairless mice were given UV radiation with and without pretreatment with 7,12-dimethylbenz(a)anthracene (DMBA), 5% benzoyl peroxide in a gel (Panoxyl), and gel alone, in various combinations, with appropriate control groups included, in order to see whether benzoyl peroxide, which is known to enhance chemical skin carcinogenesis after a single, small dose of DMBA, also enhances UV carcinogenesis. The mice were observed for skin tumors, and all skin lesions were histologically investigated. The percentage of tumor-bearing animals with time is called the tumor rate, the total number of tumors occurring is called the tumor yield. Continual treatment with 5% benzoyl peroxide in gel twice a week, with or without a short pretreatment period of UV radiation resulted in only 2 skin carcinomas, which is remarkable, but not significant. Both Panoxyl and gel alone enhanced tumorigenicity significantly in animals pretreated with a single dose of 51.2 micrograms DMBA. There was no difference between the enhancement caused by Panoxyl and the gel as regards the tumor rate, but when measured as final tumor yield, Panoxyl was slightly more tumor-enhancing than gel alone. However, both Panoxyl and gel protected significantly against UV tumorigenesis (all tumors). There was no difference between the protective effect of the 2 types of treatment. Neither Panoxyl nor gel alone influenced significantly UV skin carcinogenesis (malignant tumors). It is concluded that under these experimental conditions both Panoxyl and gel alone tend to protect against the tumorigenicity and do not enhance the carcinogenicity of UV radiation in hairless mice, whereas both gel and Panoxyl enhance chemical carcinogenesis. The carcinogenic mechanisms may be different for UV and chemical carcinogenesis, respectively.

  11. Pretreatment of paper tube residuals for improved biogas production.

    PubMed

    Teghammar, Anna; Yngvesson, Johan; Lundin, Magnus; Taherzadeh, Mohammad J; Horváth, Ilona Sárvári

    2010-02-01

    Paper tube residuals, which are lignocellulosic wastes, have been studied as substrate for biogas (methane) production. Steam explosion and nonexplosive hydrothermal pretreatment, in combination with sodium hydroxide and/or hydrogen peroxide, have been used to improve the biogas production. The treatment conditions of temperature, time and addition of NaOH and H(2)O(2) were statistically evaluated for methane production. Explosive pretreatment was more successful than the nonexplosive method, and gave the best results at 220 degrees C, 10 min, with addition of both 2% NaOH and 2% H(2)O(2). Digestion of the pretreated materials at these conditions yielded 493 N ml/g VS methane which was 107% more than the untreated materials. In addition, the initial digestion rate was improved by 132% compared to the untreated samples. The addition of NaOH was, besides the explosion effect, the most important factor to improve the biogas production.

  12. Switching off hydrogen peroxide hydrogenation in the direct synthesis process.

    PubMed

    Edwards, Jennifer K; Solsona, Benjamin; N, Edwin Ntainjua; Carley, Albert F; Herzing, Andrew A; Kiely, Christopher J; Hutchings, Graham J

    2009-02-20

    Hydrogen peroxide (H2O2) is an important disinfectant and bleach and is currently manufactured from an indirect process involving sequential hydrogenation/oxidation of anthaquinones. However, a direct process in which H2 and O2 are reacted would be preferable. Unfortunately, catalysts for the direct synthesis of H2O2 are also effective for its subsequent decomposition, and this has limited their development. We show that acid pretreatment of a carbon support for gold-palladium alloy catalysts switches off the decomposition of H2O2. This treatment decreases the size of the alloy nanoparticles, and these smaller nanoparticles presumably decorate and inhibit the sites for the decomposition reaction. Hence, when used in the direct synthesis of H2O2, the acid-pretreated catalysts give high yields of H2O2 with hydrogen selectivities greater than 95%.

  13. Thermochemical Pretreatment for Anaerobic Digestion of Sorted Waste

    NASA Astrophysics Data System (ADS)

    Hao, W.; Hongtao, W.

    2008-02-01

    The effect of alkaline hydrothermal pre-treatment for anaerobic digestion of mechanically-sorted municipal solid waste (MSW) and source-sorted waste was studied. Waste was hydrothermally pre-treated in dilute alkali solution. Hydrolysis product was incubated in 500 ml saline bottle to determine methane potential (MP) under mesospheric anaerobic conditions. Optimum reaction condition obtained in the study is 170 °C at the dose of 4 g NaOH/100 g solid for one hour. Soluble COD was 13936 mg/L and methane yield was 164 ml/g VS for 6 days incubation at optimum conditions. More than 50% biogas increase was achieved over the control, and methane conversion ratio on carbon basis was enhanced to 30.6%. The digestion period was less than 6 days when pre-treatment temperature was above 130 °C. The organic part of sorted waste is mainly constituted of kitchen garbage and leaf. Model kitchen garbage was completely liquidized at 130 °C for one hour and the methane yield was 276 ml/g VS. Addition of alkali enhance hydroxylation rate and methane yield slightly. The biogas potential of leaf could be observed by pre-treatment above 150 °C under alkaline condition.

  14. Stabilized aqueous hydrogen peroxide solution

    SciTech Connect

    Malin, M.J.; Sciafani, L.D.

    1988-05-17

    This patent describes a stabilized aqueous hydrogen peroxide solution having a pH below 7 and an amount of Ferric ion up to about 2 ppm comprising hydrogen peroxide, acetanilide having a concentration which ranges between 0.74 M Mol/L and 2.22 mMol/L, and o-benzene disulfonic acid or salt thereof at a concentration between about 0.86 mMol/L to about 1.62 mMol/L.

  15. 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 cellulosic biomass via different pretreatment technologies that yield sugars. Process simulations of dilute acid and ammonia fiber expansion pretreatment processes and subsequent hydrolysis were developed in Aspen Plus for four lignocellulosic feedstocks (corn stover, miscanthus, switchgrass, and poplar). This processing yields sugars that can be subsequently converted to biofuels or biochemical. Material and energy consumption data from Aspen Plus were then compiled in a new Greenhouses Gases, Regulated Emissions, and Energy Use in Transportation (GREETTM) 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.

  16. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  17. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is...

  18. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is...

  19. 21 CFR 173.356 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Hydrogen peroxide. 173.356 Section 173.356 Food... Specific Usage Additives § 173.356 Hydrogen peroxide. Hydrogen peroxide (CAS Reg. No. 7722-84-1) may be... to exceed 0.001 percent by weight of the whey, providing that residual hydrogen peroxide is...

  20. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  1. 21 CFR 529.1150 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrogen peroxide. 529.1150 Section 529.1150 Food... peroxide. (a) Specifications. Each milliliter of solution contains 396.1 milligrams (mg) hydrogen peroxide... group. Eggs: Some strains of rainbow trout eggs are sensitive to hydrogen peroxide treatment at a...

  2. 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.

  3. Alkaline battery, separator therefore

    NASA Technical Reports Server (NTRS)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  4. Effect of lime pre-treatment on the synergistic hydrolysis of sugarcane bagasse by hemicellulases.

    PubMed

    Beukes, Natasha; Pletschke, Brett I

    2010-06-01

    Agricultural crop wastes are typically lignocellulosic in composition and thus partially recalcitrant to enzymatic degradation. The recalcitrant nature of plant biomass and the inability to obtain complete enzymatic hydrolysis has led to the establishment of various pre-treatment strategies. Alkaline pre-treatments increase the accessibility of the exposed surface to enzymatic hydrolysis through the removal of acetyl and uronic acid substituents on hemicelluloses. Unlike the use of steam and acid pre-treatments, alkaline pre-treatments (e.g. lime) solubilise lignin and a small percentage of the hemicelluloses. The most common alkaline pre-treatments that are employed make use of sodium hydroxide and lime. This study compared the synergistic degradation of un-treated and lime pre-treated sugarcane bagasse using cellulosomal and non-cellulosomal hemicellulases as free enzymes. The enzyme combination of 37.5% ArfA and 62.5% ManA produced the highest amount of reducing sugar of 91.834 micromol/min for the degradation of un-treated bagasse. This enzyme combination produced a degree of synergy of 1.87. The free enzymes displayed an approximately 6-fold increase in the enzyme activity, i.e. the total amount of reducing sugar released (593.65 micromol/min) with the enzyme combination of 37.5% ArfA, 25% ManA and 37.5% XynA for the lime pre-treated substrate and a degree of synergy of 2.14. To conclude, this study indicated that pre-treating the sugarcane bagasse is essential, in order to increase the efficiency of lignocellulose enzymatic hydrolysis by disruption of the lignin sheath, that the lime pre-treatment did not have any dramatic effect on the synergistic relationship between the free enzymes, and that time may play an important role in the establishment of synergistic relationships between enzymes.

  5. Alkaline solubilization and microwave irradiation as a combined sludge disintegration and minimization method.

    PubMed

    Doğan, Ilgin; Sanin, F Dilek

    2009-05-01

    Commonly used pretreatment method of alkaline solubilization (using NaOH) and a relatively new technology of microwave (MW) irradiation (160 degrees C) were combined as a pretreatment method of waste activated sludge (WAS) in this study. First alkaline and MW pretreatment methods were examined separately, then their combination for different conditions was investigated in terms of their effect on COD solubilization, turbidity and capillary suction time (CST). For combined pretreatments, soluble COD to total COD ratio (SCOD/TCOD) of WAS increased from 0.005 (control) to 0.18, 0.27, 0.34 and 0.37 for combined methods of MW and pH-10, 11, 12 and 12.5, respectively. Deteriorated dewaterability due to alkaline pretreatment was also improved due to the incorporation of MW irradiation. Further, with small scale batch anaerobic reactors, pH-10, pH-12, MW (alone), MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested. Highest total gas and methane productions were achieved with MW+pH-12 pretreatment with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors for 92 days and compared to that of the control reactors. These reactors were operated at an SRT of 15 days. After steady state, 43.5% and 55% improvements were obtained in respective daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively based on a relative calculation with respect to control reactors. This way combined alkaline-microwave treatment proved to be an effective sludge minimization method. Pretreated digested sludge had 22% improved dewaterability than unpretreated digested sludge. Higher SCOD and NH(3)-N concentrations were measured in the pretreated digested sludge supernatant; however, PO(4)-P concentration did not increase much.

  6. Fungal pretreatment of lignocellulosic biomass.

    PubMed

    Wan, Caixia; Li, Yebo

    2012-01-01

    Pretreatment is a crucial step in the conversion of lignocellulosic biomass to fermentable sugars and biofuels. Compared to thermal/chemical pretreatment, fungal pretreatment reduces the recalcitrance of lignocellulosic biomass by lignin-degrading microorganisms and thus potentially provides an environmentally-friendly and energy-efficient pretreatment technology for biofuel production. This paper provides an overview of the current state of fungal pretreatment by white rot fungi for biofuel production. The specific topics discussed are: 1) enzymes involved in biodegradation during the fungal pretreatment; 2) operating parameters governing performance of the fungal pretreatment; 3) the effect of fungal pretreatment on enzymatic hydrolysis and ethanol production; 4) efforts for improving enzymatic hydrolysis and ethanol production through combinations of fungal pretreatment and physical/chemical pretreatment; 5) the treatment of lignocellulosic biomass with lignin-degrading enzymes isolated from fungal pretreatment, with a comparison to fungal pretreatment; 6) modeling, reactor design, and scale-up of solid state fungal pretreatment; and 7) the limitations and future perspective of this technology.

  7. A critical reinvestigation of the TAED-activated peroxide system for low-temperature bleaching of cotton.

    PubMed

    Xu, Changhai; Long, Xiaoxia; Du, Jinmei; Fu, Shaohai

    2013-01-30

    There exists a misunderstanding on the TAED-activated peroxide system in the textile industry that H(2)O(2) used in excess of the stoichiometric amount could produce an addition effect on bleaching of cotton under alkaline conditions. In this study, a critical reinvestigation was carried out on the TAED-activated peroxide system for bleaching of cotton. It was found that the TAED-activated peroxide system achieved its best performance under near-neutral pH conditions. No addition effect was observed when an excessive amount of H(2)O(2) was used under alkaline conditions, which is probably due to the base-catalyzed bimolecular decomposition of peracetic acid and the nucleophilic attack by H(2)O(2) on peracetic acid. NaHCO(3) was shown to be a desired alkaline agent for maintaining near-neutral pH for the TAED-activated peroxide system. This study provides new insight into the application of the TAED-activated peroxide system for low-temperature bleaching of cotton under more environmentally benign conditions.

  8. Comparison of Seven Chemical Pretreatments of Corn Straw for Improving Methane Yield by Anaerobic Digestion

    PubMed Central

    Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

    2014-01-01

    Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS −1 in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost. PMID:24695485

  9. Comparison of seven chemical pretreatments of corn straw for improving methane yield by anaerobic digestion.

    PubMed

    Song, Zilin; GaiheYang; Liu, Xiaofeng; Yan, Zhiying; Yuan, Yuexiang; Liao, Yinzhang

    2014-01-01

    Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS(-1) in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost.

  10. Influence of HCl pretreatment on laser diffraction measurements

    NASA Astrophysics Data System (ADS)

    Schulte, Philipp; Steininger, Florian; Lockot, Gregori; Lehmkuhl, Frank; Stauch, Georg; Protze, Jens; Fischer, Peter

    2014-05-01

    Sample pretreatment methods in grain size (GS) analyses differ and their influence on GS distributions has been subject of controversial discussions. The standard sample preparation usually comprises the disaggregation into single primary particles. The organic binding material is oxidized by hydrogen peroxide (H2O2) and the containing carbonates are dissolved by hydrochloric acid (HCl). However, laser diffraction measurements of calcified sediment sequences or sediments with high contents of organic matter show non-reproducible changes in the GS distribution. To investigate variations of the GS distribution, selected samples from two different sections in different stages of weathering and sedimentary genesis were measured using a Beckman Coulter LS13320 laser particle size analyser. A high-resolution Holocene sandy loess-paleosol sequence, the Suohuduo section on the eastern margin of the Tibetan Plateau, was investigated. The results were compared with a Pleistocene loess sequence from the Lower Rhine Embayment, the Düsseldorf-Grafenberg section. The entire sample set includes samples of siliciclastic, barely weathered material and sediments from paleosols. The paleosols in the Suohudo section are strongly influenced by steppe fires and are rich in organo-mineral associations and pyrogenic carbon. All samples were pretreated with hydrogen peroxide and sodium pyrophosphate. In order to investigate the influence of HCl on the GS distribution, the samples were subsequently prepared with and without the addition of HCl. The results show that the sample preparation has a significant influence on the detected GS distribution. Hence, prior to the measurement of a sample set, the effectiveness of the pretreatment argents HCl and H2O2 should be evaluated. In order to generate a valid GS distribution, the sample pretreatment must be matched to the aim of the study and the composition of the sample. Paleoclimatic and environmental interpretation based on improper GS

  11. Electrocatalysis of hydrogen peroxide reactions on perovskite oxides: experiment versus kinetic modeling.

    PubMed

    Poux, T; Bonnefont, A; Ryabova, A; Kéranguéven, G; Tsirlina, G A; Savinova, E R

    2014-07-21

    Hydrogen peroxide has been identified as a stable intermediate of the electrochemical oxygen reduction reaction on various electrodes including metal, metal oxide and carbon materials. In this article we study the hydrogen peroxide oxidation and reduction reactions in alkaline medium using a rotating disc electrode (RDE) method on oxides of the perovskite family (LaCoO3, LaMnO3 and La0.8Sr0.2MnO3) which are considered as promising electrocatalytic materials for the cathode of liquid and solid alkaline fuel cells. The experimental findings, such as the higher activity of Mn-compared to that of Co-perovskites, the shape of RDE curves, and the influence of the H2O2 concentration, are rationalized with the help of a microkinetic model.

  12. Biomass pretreatments capable of enabling lignin valorization in a biorefinery process.

    PubMed

    Narron, Robert H; Kim, Hoyong; Chang, Hou-Min; Jameel, Hasan; Park, Sunkyu

    2016-04-01

    Recent techno-economic studies of proposed lignocellulosic biorefineries have concluded that creating value from lignin will assist realization of biomass utilization into valuable fuels, chemicals, and materials due to co-valorization and the new revenues beyond carbohydrates. The pretreatment step within a biorefinery process is essential for recovering carbohydrates, but different techniques and intensities have a variety of effects on lignin. Acidic and alkaline pretreatments have been shown to produce diverse lignins based on delignification chemistry. The valorization potential of pretreated lignin is affected by its chemical structure, which is known to degrade, including inter-lignin condensation under high-severity pretreatment. Co-valorization of lignin and carbohydrates will require dampening of pretreatment intensities to avoid such effects, in spite of tradeoffs in carbohydrate production.

  13. 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

  14. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    NASA Astrophysics Data System (ADS)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  15. Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng

    2015-05-01

    Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near

  16. Progress toward hydrogen peroxide micropulsion

    SciTech Connect

    Whitehead, J C; Dittman, M D; Ledebuhr, A G

    1999-07-08

    A new self-pressurizing propulsion system has liquid thrusters and gas jet attitude control without heavy gas storage vessels. A pump boosts the pressure of a small fraction of the hydrogen peroxide, so that reacted propellant can controllably pressurize its own source tank. The warm decomposition gas also powers the pump and is supplied to the attitude control jets. The system has been incorporated into a prototype microsatellite for terrestrial maneuvering tests. Additional progress includes preliminary testing of a bipropellant thruster, and storage of unstabilized hydrogen peroxide in small sealed tanks.

  17. Biomass shock pretreatment

    SciTech Connect

    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. Evaluation of ultrasound assisted potassium permanganate pre-treatment of spent coffee waste.

    PubMed

    Ravindran, Rajeev; Jaiswal, Swarna; Abu-Ghannam, Nissreen; Jaiswal, Amit K

    2017-01-01

    In the present study, novel pre-treatment for spent coffee waste (SCW) has been proposed which utilises the superior oxidising capacity of alkaline KMnO4 assisted by ultra-sonication. The pre-treatment was conducted for different exposure times (10, 20, 30 and 40min) using different concentrations of KMnO4 (1, 2, 3, 4, 5%w/v) at room temperature with solid/liquid ratio of 1:10. Pretreating SCW with 4% KMnO4 and exposing it to ultrasound for 20min resulted in 98% cellulose recovery and a maximum lignin removal of 46%. 1.7 fold increase in reducing sugar yield was obtained after enzymatic hydrolysis of KMnO4 pretreated SCW as compared to raw. SEM, XRD and FTIR analysis of the pretreated SCW revealed the various effects of pretreatment. Thermal behaviour of the pretreated substrate against the native biomass was also studied using DSC. Ultrasound-assisted potassium permanganate oxidation was found to be an effective pretreatment for SCW, and can be a used as a potential feedstock pretreatment strategy for bioethanol production.

  19. Modelling of pretreatment and saccharification with different feedstocks and kinetic modeling of sorghum saccharification.

    PubMed

    Prathyusha, N; Kamesh, Reddi; Rani, K Yamuna; Sumana, C; Sridhar, S; Prakasham, R S; Yashwanth, V V N; Sheelu, G; Kumar, M Pradeep

    2016-12-01

    Experiments have been performed for pretreatment of sorghum, wheat straw and bamboo through high temperature alkali pretreatment with different alkaline loading and temperatures, and the data on extent of delignification in terms of the final compositions of cellulose, hemicellulose and lignin have been generated. Further, enzymatic saccharification has been carried out in all the cases to find the extent of conversion possible after 72h. The effect of different operating parameters on the extent of delignification and cellulose conversion are evaluated. This data is employed to develop a generalized multi-feedstock and individual feedstock based models which can be used to determine the extent of delignification and cellulose conversion for any and specific biomass respectively with alkaline pretreatment and similar enzyme conditions as considered in the present study. Also, a kinetic model is developed and validated for sorghum for cellulosic conversion.

  20. Platinum-rare earth cathodes for direct borohydride-peroxide fuel cells

    NASA Astrophysics Data System (ADS)

    Cardoso, D. S. P.; Santos, D. M. F.; Šljukić, B.; Sequeira, C. A. C.; Macciò, D.; Saccone, A.

    2016-03-01

    Hydrogen peroxide (H2O2) is being actively investigated as an oxidant for direct borohydride fuel cells. Herein, platinum-rare earth (RE = Sm, Dy, Ho) alloys are prepared by arc melting and their activity for hydrogen peroxide reduction reaction (HPRR) is studied in alkaline media. Cyclic voltammetry and chronoamperometry measurements show that Pt-Sm electrode displays the highest catalytic activity for HPRR with the lowest activation energy, followed by Pt-Ho, while Pt-Dy alloys show practically no activity. Laboratory direct borohydride-peroxide fuel cells (DBPFCs) are assembled using these alloys. The DBPFC with Pt-Sm cathode gives the highest peak power density of 85 mW cm-2, which is more than double of that obtained in a DBPFC with Pt electrodes.

  1. 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).

  2. Safety in the Chemical Laboratory. Organic Peroxides.

    ERIC Educational Resources Information Center

    Shanley, Edward S.

    1990-01-01

    Discussed is the thermodynamic instability of organic peroxides. The process of autoxidation which results in peroxide formation is described. Precautions necessary to prevent autoxidation hazards associated with these reagents are suggested. (CW)

  3. 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.

  4. Improved dual flow aluminum hydrogen peroxide battery

    SciTech Connect

    Marsh, C.; Licht, S.L.; Matthews, D.

    1993-11-30

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  5. Improved dual flow aluminum hydrogen peroxide battery

    NASA Astrophysics Data System (ADS)

    Marsh, Catherine; Licht, Stuart L.; Matthews, Donna

    1993-11-01

    A novel dual flow battery configuration is provided comprising an aqueous hydrogen peroxide catholyte, an aqueous anolyte, a porous solid electrocatalyst capable of reducing said hydrogen peroxide and separating said anolyte, and an aluminum anode positioned within said anolyte. Separation of catholyte and anolyte chambers prevents hydrogen peroxide poisoning of the aluminum anode.

  6. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  7. Sampling Stoichiometry: The Decomposition of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Clift, Philip A.

    1992-01-01

    Describes a demonstration of the decomposition of hydrogen peroxide to provide an interesting, quantitative illustration of the stoichiometric relationship between the decomposition of hydrogen peroxide and the formation of oxygen gas. This 10-minute demonstration uses ordinary hydrogen peroxide and yeast that can be purchased in a supermarket.…

  8. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  9. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  10. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  11. 21 CFR 582.1366 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrogen peroxide. 582.1366 Section 582.1366 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1366 Hydrogen peroxide. (a) Product. Hydrogen peroxide. (b) (c) Limitations,...

  12. Safety Tips: Peroxides Can Be Treacherous.

    ERIC Educational Resources Information Center

    Nagel, Miriam C.

    1984-01-01

    Peroxides are unstable, shock-, thermal-, and friction-sensitive compounds whose sensitivity increases with concentration. In addition, peroxides can form in aging organic solvents and stored alkali metals. Cautions related to storage, use, and disposal of peroxides in the secondary school chemistry laboratory are discussed. (JN)

  13. Inner-shell excitation spectroscopy of peroxides

    NASA Astrophysics Data System (ADS)

    Harding, K. L.; Kalirai, S.; Hayes, R.; Ju, V.; Cooper, G.; Hitchcock, A. P.; Thompson, M. R.

    2015-11-01

    O 1s inner-shell excitation spectra of a number of vapor phase molecules containing peroxide bonds - hydrogen peroxide (H2O2), di-t-butylperoxide (tBuOtBu), benzoyl peroxide, ((C6H5(CO)O)2), luperox-F [1,3(4)-bis(tertbutylperoxyisopropyl) benzene], and analogous, non-peroxide compounds - water, t-butanol and benzoic acid have been measured. C 1s spectra are also reported. O 1s spectra of solid benzoic acid, di-t-butylperoxide and luperox-F recorded using a scanning transmission X-ray microscope, are also reported, and compared to the corresponding gaseous spectra. Spectral interpretation was aided by comparing the spectra of the peroxide and non-peroxide counterparts and with ab initio calculations. A characteristic O 1s → σ∗O-O transition at 533.0(3) eV is identified in each peroxide species, which is absent in the corresponding non-peroxide counterpart species. The energy and intensity of the 533 eV peroxide feature is stable and thus useful for analysis of peroxides in mixtures, such as tracking residual peroxide initiators, or peroxides produced in fuel cells.

  14. 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

  15. Enzymatic Pre-Treatment Increases the Protein Bioaccessibility and Extractability in Dulse (Palmaria palmata)

    PubMed Central

    Mæhre, Hanne K.; Jensen, Ida-Johanne; Eilertsen, Karl-Erik

    2016-01-01

    Several common protein extraction protocols have been applied on seaweeds, but extraction yields have been limited. The aims of this study were to further develop and optimize existing extraction protocols and to examine the effect of enzymatic pre-treatment on bioaccessibility and extractability of seaweed proteins. Enzymatic pre-treatment of seaweed samples resulted in a three-fold increase in amino acids available for extraction. Combining enzymatic pre-treatment with alkaline extraction resulted in a 1.6-fold increase in the protein extraction yield compared to a standard alkaline extraction protocol. A simulated in vitro gastrointestinal digestion model showed that enzymatic pre-treatment of seaweed increased the amount of amino acids available for intestinal absorption 3.2-fold. In conclusion, enzymatic pre-treatment of seaweeds is effective for increasing the amount of amino acids available for utilization and may thus be an effective means for increasing the utilization potential of seaweed proteins. However, both the enzymatic pre-treatment protocol and the protein extraction protocol need further optimization in order to obtain optimal cost-benefit and results from the in vitro gastrointestinal digestion model need to be confirmed in clinical models. PMID:27792166

  16. 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

  17. Regulation of collagen synthesis in human dermal fibroblasts by ascorbic-induced lipid peroxidation

    SciTech Connect

    Geesin, J.C. Johnson and Johnson Consumer Products, Inc., Skillman, NJ ); Gordon, J.S. ); Gordon, J.S. ); Berg, R.A. )

    1991-03-11

    Ascorbic acid has been shown to stimulate collagen synthesis through the induction of lipid peroxidation which leads to increased transcription of the collagen genes. To test the ability of aldehyde products of lipid peroxidation to mediate this effect, the authors treated cultured fibroblasts with 1-200{mu}M of malondialdehyde, acetaldehyde, glyoxal or hexenal in the presence of lipid peroxidation inducing or noninducing concentrations of ascorbic acid. The treatment process involved either pretreatment of cells for 66hrs with either concentration of ascorbate before a 6hr treatment in the presence of ascorbate and the aldehydes, or 6 or 72hr treatment of the cells in the presence of either concentration of ascorbate plus the aldehydes. No effect of any of these aldehydes was seen on ascorbate-stimulated collagen synthesis. Also, pretreatment of fibroblasts for 24hrs with 100nM phorbol myristate acetate (PMA), which produces down regulation of protein kinase C(PKC), failed to alter the ascorbate-stimulation of collagen synthesis. Additionally, the authors tested the ability of benzamide, a poly ACP ribosylation inhibitor, to inhibit the ascorbate response with no specific effect noted. These results do not support the proposed roles for aldehydes, PKC, or poly ADP ribosylation in the mediation of the lipid peroxidation induced stimulation of collagen synthesis.

  18. Role of sialic acid and alkaline DNase in breast cancer.

    PubMed

    Raval, G N; Parekh, L J; Patel, M M; Patel, P S; Rawal, R M; Balar, D B; Patel, D D

    1997-01-01

    Serum levels of sialic acid and alkaline DNase (ADA) were analysed in 495 blood samples collected from 170 breast cancer patients before and during/after anticancer treatment. Fifty-six healthy females were included in the study to define the cutoff values. The markers were analysed by highly sensitive spectrophotometric methods. Statistical evaluation of the data was done using Student's 't' test, paired 't' test and ROC curve analysis. The total sialic acid (TSA), lipid bound sialic acid (LSA) and ADA in sera of untreated breast cancer patients were significantly higher than in controls. ROC curve analysis revealed TSA and LSA to be useful markers for diagnosis of breast cancer. Serum levels of TSA and LSA were significantly decreased in complete responders as compared to their pretreatment values. The pretreatment ADA values showed much individual variation. However, responders showed higher levels of ADA than untreated patients. In nonresponders the values of the biomarkers were comparable with pretreatment levels. The study suggested that TSA and LSA can be helpful in the diagnosis of breast cancer. All three markers can be used for assessment of response to anticancer treatment in breast cancer patients.

  19. Zinc electrode in alkaline electrolyte

    SciTech Connect

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  20. 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.

  1. A novel amperometric biosensor based on artichoke (Cynara scolymus L.) tissue homogenate immobilized in gelatin for hydrogen peroxide detection.

    PubMed

    Oztürk, G; Ertaş, F N; Akyilmaz, E; Dinçkaya, E; Tural, H

    2004-01-01

    A biosensor for specific determination of hydrogen peroxide was developed by using homogenized artichoke (Cynara scolymus L.) tissue in combination with a dissolved oxygen probe and applied in determination of hydrogen peroxide in milk samples. Artichoke tissue, which has catalase activity, was immobilized with gelatine by means of glutaraldehyde and fixed on a pretreated teflon membrane. The electrode response was maximum when 0.05 M phosphate buffer was used at pH 7.0 and at 30 degrees C. Upon addition of hydrogen peroxide, the electrode gives a linear response in a concentration range of 5.0-50 x 10(-5) M with a response time of 3 min. The method was also applied to the determination of hydrogen peroxide in milk samples.

  2. Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin.

    PubMed

    See, S F; Ghassem, M; Mamot, S; Babji, A S

    2015-02-01

    Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.

  3. Vitamin D3 pretreatment alleviates renal oxidative stress in lipopolysaccharide-induced acute kidney injury.

    PubMed

    Xu, Shen; Chen, Yuan-Hua; Tan, Zhu-Xia; Xie, Dong-Dong; Zhang, Cheng; Xia, Mi-Zhen; Wang, Hua; Zhao, Hui; Xu, De-Xiang; Yu, De-Xin

    2015-08-01

    Increasing evidence demonstrates that reactive oxygen species plays important roles in sepsis-induced acute kidney injury. This study investigated the effects of VitD3 pretreatment on renal oxidative stress in sepsis-induced acute kidney injury. Mice were intraperitoneally injected with lipopolysaccharide (LPS, 2.0mg/kg) to establish an animal model of sepsis-induced acute kidney injury. In VitD3+LPS group, mice were orally pretreated with three doses of VitD3 (25 μg/kg) at 1, 24 and 48 h before LPS injection. As expected, oral pretreatment with three daily recommended doses of VitD3 markedly elevated serum 25(OH)D concentration and efficiently activated renal VDR signaling. Interestingly, LPS-induced renal GSH depletion and lipid peroxidation were markedly alleviated in VitD3-pretreated mice. LPS-induced serum and renal nitric oxide (NO) production was obviously suppressed by VitD3 pretreatment. In addition, LPS-induced renal protein nitration, as determined by 3-nitrotyrosine residue, was obviously attenuated by VitD3 pretreatment. Further analysis showed that LPS-induced up-regulation of renal inducible nitric oxide synthase (inos) was repressed in VitD3-pretreated mice. LPS-induced up-regulation of renal p47phox and gp91phox, two NADPH oxidase subunits, were normalized by VitD3 pretreatment. In addition, LPS-induced down-regulation of renal superoxide dismutase (sod) 1 and sod2, two antioxidant enzyme genes, was reversed in VitD3-pretreated mice. Finally, LPS-induced tubular epithelial cell apoptosis, as determined by TUNEL, was alleviated by VitD3 pretreatment. Taken together, these results suggest that VitD3 pretreatment alleviates LPS-induced renal oxidative stress through regulating oxidant and antioxidant enzyme genes.

  4. Improved Electrolytic Hydrogen Peroxide Generator

    NASA Technical Reports Server (NTRS)

    James, Patrick I.

    2005-01-01

    An improved apparatus for the electrolytic generation of hydrogen peroxide dissolved in water has been developed. The apparatus is a prototype of H2O2 generators for the safe and effective sterilization of water, sterilization of equipment in contact with water, and other applications in which there is need for hydrogen peroxide at low concentration as an oxidant. Potential applications for electrolytic H2O2 generators include purification of water for drinking and for use in industrial processes, sanitation for hospitals and biotechnological industries, inhibition and removal of biofouling in heat exchangers, cooling towers, filtration units, and the treatment of wastewater by use of advanced oxidation processes that are promoted by H2O2.

  5. Detection of hydrogen peroxide with chemiluminescent micelles.

    PubMed

    Lee, Dongwon; Erigala, Venkata R; Dasari, Madhuri; Yu, Junhua; Dickson, Robert M; Murthy, Niren

    2008-01-01

    The overproduction of hydrogen peroxide is implicated in the progress of numerous life-threatening diseases and there is a great need for the development of contrast agents that can detect hydrogen peroxide in vivo. In this communication, we present a new contrast agent for hydrogen peroxide, termed peroxalate micelles, which detect hydrogen peroxide through chemiluminescence, and have the physical/chemical properties needed for in vivo imaging applications. The peroxalate micelles are composed of amphiphilic peroxalate based copolymers and the fluorescent dye rubrene, they have a 'stealth' polyethylene glycol (PEG) corona to evade macrophage phagocytosis, and a diameter of 33 nm to enhance extravasation into permeable tissues. The peroxalate micelles can detect nanomolar concentrations of hydrogen peroxide (>50 nM) and thus have the sensitivity needed to detect physiological concentrations of hydrogen peroxide. We anticipate numerous applications of the peroxalate micelles for in vivo imaging of hydrogen peroxide, given their high sensitivity, small size, and biocompatible PEG corona.

  6. NASA Hydrogen Peroxide Propulsion Perspective

    NASA Technical Reports Server (NTRS)

    Unger, Ronald; Lyles, Garry M. (Technical Monitor)

    2002-01-01

    This presentation is to provide the current status of NASA's efforts in the development of hydrogen peroxide in both mono-propellant and bi-propellant applications, consistent with the Space Launch Initiative goals of pursuing low toxicity and operationally simpler propellants for application in the architectures being considered for the 2nd Generation Reusable Launch Vehicle, also known as the Space Launch Initiative, or SLI.

  7. Industrial-scale steam explosion pretreatment of sugarcane straw for enzymatic hydrolysis of cellulose for production of second generation ethanol and value-added products.

    PubMed

    Oliveira, Fernando M V; Pinheiro, Irapuan O; Souto-Maior, Ana M; Martin, Carlos; Gonçalves, Adilson R; Rocha, George J M

    2013-02-01

    Steam explosion at 180, 190 and 200°C for 15min was applied to sugarcane straw in an industrial sugar/ethanol reactor (2.5m(3)). The pretreated straw was delignificated by sodium hydroxide and hydrolyzed with cellulases, or submitted directly to enzymatic hydrolysis after the pretreatment. The pretreatments led to remarkable hemicellulose solubilization, with the maximum (92.7%) for pretreatment performed at 200°C. Alkaline treatment of the pretreated materials led to lignin solubilization of 86.7% at 180°C, and only to 81.3% in the material pretreated at 200°C. All pretreatment conditions led to high hydrolysis conversion of cellulose, with the maximum (80.0%) achieved at 200°C. Delignification increase the enzymatic conversion (from 58.8% in the cellulignin to 85.1% in the delignificated pulp) of the material pretreated at 180°C, but for the material pretreated at 190°C, the improvement was less remarkable, while for the pretreated at 200°C the hydrolysis conversion decreased after the alkaline treatment.

  8. Stainless steel anodes for alkaline water electrolysis and methods of making

    SciTech Connect

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  9. Establishment of an activated peroxide system for low-temperature cotton bleaching using N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride.

    PubMed

    Xu, Changhai; Hinks, David; Sun, Chang; Wei, Qufu

    2015-03-30

    Cotton bleaching is traditionally carried out in strongly alkaline solution of hydrogen peroxide (H2O2) at temperatures close to the boil. Such harsh processing conditions can result in extensive water and energy consumptions as well as severe chemical damage to textiles. In this study, an activated peroxide system was established for low-temperature cotton bleaching by incorporating a bleach activator, namely N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC) into an aqueous H2O2 solution. Experimental results showed that the TBBC-activated peroxide system exhibited the most effective bleaching performance in a pH range of 6-8 which could be approximated by adding sodium bicarbonate (NaHCO3). The TBBC/H2O2/NaHCO3 system led to rapid bleaching of cotton at a temperature as low as 50°C. In comparison with the hot alkaline peroxide bleaching system, the TBBC/H2O2/NaHCO3 system provided cotton fabric with an equivalent degree of whiteness, higher degree of polymerization, and slightly lower water absorbency. The new activated peroxide system may provide a more environmentally benign approach to cotton bleaching.

  10. Polarographic study of hydrogen peroxide anodic current and its application to antioxidant activity determination.

    PubMed

    Sužnjević, Desanka Ž; Pastor, Ferenc T; Gorjanović, Stanislava Ž

    2011-09-15

    Behavior of hydrogen peroxide in alkaline medium has been studied by direct current (DC) polarography with dropping mercury electrode (DME) aiming to apply it in antioxidant (AO) activity determination. Development of a peroxide anodic current having form of a peak, instead of common polarographic wave, has been investigated. As a base for this investigation the interaction of H(2)O(2) with anodically dissolved mercury was followed. Formation of mercury complex [Hg(O(2)H)(OH)] has been confirmed. The relevant experimental conditions, such as temperature, concentration and pH dependence, as well as time stability of hydrogen peroxide anodic current, have been assessed. Development of an AO assay based on decrease of anodic current of hydrogen peroxide in the presence of antioxidants (AOs) has been described. Under optimized working conditions, a series of benzoic acids along with corresponding cinnamate analogues have been tested for hydrogen peroxide scavenging activity. In addition, the assay versatility has been confirmed on various complex samples.

  11. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, David B.; Lao, Guifang

    1998-01-01

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium.

  12. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, D.B.; Lao, G.

    1998-01-06

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium. 3 figs.

  13. [Enhancement of anaerobic digestion of excess sludge by acid-alkali pretreatment].

    PubMed

    Yuan, Guang-Huan; Zhou, Xing-Qiu; Wu, Jian-Dong

    2012-06-01

    In order to enhance the efficiency of anaerobic digestion of excess sludge, acid-alkali pretreatment method was studied. Three different pretreatment methods (alkali alone,acid-alkali, alkali-acid) were compared to investigate their impacts on hydrolysis and acidification of activated sludge. In addition, their influences on methane-producing in subsequent anaerobic digestion process were also studied. The results showed that the soluble chemical oxygen demand (SCOD) of alkaline treatment alone was about 16% higher than the combining of acid and alkali treatment, SCOD concentration increased to 5406.1 mg x L(-1) after 8 d pretreatment. After treated by acid (pH 4.0, 4 d) and alkali (pH 10.0, 4 d), the acetic acid production and its content in short-chain fatty acids (SCFAs) were higher than other pretreatment methods. And the acetic acid production (as COD/VSS) could reach 74.4 mg x g(-1), accounting for 60.5% of SCFAs. After acid-alkali pretreatment, the C: N ratio of the sludge mixed liquor was about 25, and the C: P ratio was between 35-40, which was more favorable than C: N and C: P ratio of alkali alone and alkali-acid to subsequent anaerobic digestion. The control experiments showed that, after acid-alkali pretreatment, anaerobic digestion cumulative methane yield (CH4/VSS(in)) reached to 136.1 mL x g(-1) at 15 d, which was about 2.5-, 1.6-, and 1.7-fold of the blank (unpretreated), alkali alone pretreatment and alkali-acid pretreatment, respectively. After acid-alkali pretreatment for 8 d and anaerobic digestion for 15 d, the removal efficiency of VSS was about 60.9%, and the sludge reduction effect was better than other pretreatments. It is obvious that the acid-alkali pretreatment method was more favorable to anaerobic digestion and sludge reduction.

  14. Pretreatment with polyamines alleviate the deleterious effects of diuron in maize leaves.

    PubMed

    Durmuş, Nuran; Bekircan, Tuba

    2015-03-01

    The effects of diuron, a photosystem II inhibiting herbicide, on lipid peroxidation, photosynthetic pigments, soluble protein, proline contents and some antioxidant enzymes in maize leaves were studied and protective effects of polyamines against diuron toxicity were investigated. Diuron significantly increased lipid peroxidation, suggesting oxidative damage in the plants and proline content, while it decreased total chlorophyll, carotenoid and soluble protein levels in the leaves during the experiments. Pretreatment with polyamines statistically decreased lipid peroxidation induced by diuron and spermine (SPM) proved to be the most effective polyamine. Also, pretreatment with polyamines significantly prevented the losses of total chlorophyll, carotenoid and soluble protein induced by diuron. On the other hand, pretreatment with polyamines significantly increased proline contents of the leaves in comparison with the leaves treated with diuron. Superoxide dismutase (SOD), guaiacol peroxidase (GPX) and glutathione reductase (GR) activities increased in the leaves treated with diuron while catalase (CAT ) activity decreased. Pretreatment with spermidine (SPD) did not change significantly SOD activity at 24 and 72 hrs of diuron treatment but prevented the increase in SOD activity induced by diuron at 48 h. However, pretreatment with SPD increased GPX activity at 24 h and GR activity at 48 and 72 hrs. CAT activity in the leaves pretreated with SPD was similar to that of the leaves treated with diuron. Pretreatment with SPM prevented the increase in SOD activity induced by diuron at 48 h but significantly increased it at 72 h of diuron treatment. However, pretreatment with SPM did not significantly change GPX and GR activities during the experiments but reversed the decrease in CAT activity induced by diuron at 72 h. Pretreatment with putrescine (PUT) prevented the increase in SOD activity induced by diuron at 48 and 72 hrs while it increased GPX and GR activities at 48

  15. Enzymatic saccharification and bioethanol production from Cynara cardunculus pretreated by steam explosion.

    PubMed

    Fernandes, Maria C; Ferro, Miguel D; Paulino, Ana F C; Mendes, Joana A S; Gravitis, Janis; Evtuguin, Dmitry V; Xavier, Ana M R B

    2015-06-01

    The correct choice of the specific lignocellulosic biomass pretreatment allows obtaining high biomass conversions for biorefinery implementations and cellulosic bioethanol production from renewable resources. Cynara cardunculus (cardoon) pretreated by steam explosion (SE) was involved in second-generation bioethanol production using separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF) processes. Steam explosion pretreatment led to partial solubilisation of hemicelluloses and increased the accessibility of residual polysaccharides towards enzymatic hydrolysis revealing 64% of sugars yield against 11% from untreated plant material. Alkaline extraction after SE pretreatment of cardoon (CSEOH) promoted partial removal of degraded lignin, tannins, extractives and hemicelluloses thus allowing to double glucose concentration upon saccharification step. Bioethanol fermentation in SSF mode was faster than SHF process providing the best results: ethanol concentration 18.7 g L(-1), fermentation efficiency of 66.6% and a yield of 26.6g ethanol/100 g CSEOH or 10.1 g ethanol/100 g untreated cardoon.

  16. Should we pretreat solid waste prior to anaerobic digestion? An assessment of its environmental cost.

    PubMed

    Carballa, Marta; Duran, Cecilia; Hospido, Almudena

    2011-12-15

    Many studies have shown the effectiveness of pretreatments prior to anaerobic digestion of solid wastes, but to our knowledge, none analyzes their environmental consequences/costs. In this work, seven different pretreatments applied to two types of waste (kitchen waste and sewage sludge) have been environmentally evaluated by using life cycle assessment (LCA) methodology. The results show that the environmental burdens associated to the application of pretreatments prior to anaerobic digestion cannot be excluded. Among the options tested, the pressurize-depressurize and chemical (acid or alkaline) pretreatments could be recommended on the basis of their beneficial net environmental performance, while thermal and ozonation alternatives require energy efficiency optimization to reduce their environmental burdens. Reconciling operational, economic and environmental aspects in a holistic approach for the selection of the most sustainable option, mechanical (e.g., pressurize-depressurize) and chemical methods appear to be the most appropriate alternatives at this stage.

  17. Delignification outperforms alkaline extraction for xylan fingerprinting of oil palm empty fruit bunch.

    PubMed

    Murciano Martínez, Patricia; Kabel, Mirjam A; Gruppen, Harry

    2016-11-20

    Enzyme hydrolysed (hemi-)celluloses from oil palm empty fruit bunches (EFBs) are a source for production of bio-fuels or chemicals. In this study, after either peracetic acid delignification or alkaline extraction, EFB hemicellulose structures were described, aided by xylanase hydrolysis. Delignification of EFB facilitated the hydrolysis of EFB-xylan by a pure endo-β-1,4-xylanase. Up to 91% (w/w) of the non-extracted xylan in the delignified EFB was hydrolysed compared to less than 4% (w/w) of that in untreated EFB. Alkaline extraction of EFB, without prior delignification, yielded only 50% of the xylan. The xylan obtained was hydrolysed only for 40% by the endo-xylanase used. Hence, delignification alone outperformed alkaline extraction as pretreatment for enzymatic fingerprinting of EFB xylans. From the analysis of the oligosaccharide-fingerprint of the delignified endo-xylanase hydrolysed EFB xylan, the structure was proposed as acetylated 4-O-methylglucuronoarabinoxylan.

  18. Germination pretreatments to break hard-seed dormancy in Astragalus cicer L. (Fabaceae)

    PubMed Central

    2016-01-01

    Conservationists often propagate rare species to improve their long-term population viability. However, seed dormancy can make propagation efforts challenging by substantially lowering seed germination. Here I statistically compare several pretreatment options for seeds of Astragalus cicer L.: unscarified controls and scarification via physical damage, hot water, acid, and hydrogen peroxide. Although only 30% of unscarified seeds germinated, just physical scarification significantly improved germination, whereas one treatment, hot water, resulted in no germination at all. I recommend that rare species of Astragalus, as well as other hard-seeded legumes, be pretreated using physical scarification. Other methods may require considerable optimization, wasting precious time and seeds. PMID:27833803

  19. Hierarchy of Pyrophosphate-Functionalized Uranyl Peroxide Nanocluster Synthesis.

    PubMed

    Dembowski, Mateusz; Colla, Christopher A; Hickam, Sarah; Oliveri, Anna F; Szymanowski, Jennifer E S; Oliver, Allen G; Casey, William H; Burns, Peter C

    2017-04-10

    Herein, we report a new salt of a pyrophosphate-functionalized uranyl peroxide nanocluster {U24Pp12} (1) exhibiting Oh molecular symmetry both in the solid and solution. Study of the system yielding 1 across a wide range of pH by single-crystal X-ray diffraction, small-angle X-ray scattering, and a combination of traditional (31)P and diffusion-ordered spectroscopy (DOSY) NMR affords unprecedented insight into the amphoteric chemistry of this uranyl peroxide system. Key results include formation of a rare binary {U24}·{U24Pp12} (3) system observed under alkaline conditions, and evidence of acid-promoted decomposition of {U24Pp12} (1) followed by spatial rearrangement and condensation of {U4} building blocks into the {U32Pp16} (2) cluster. Furthermore, (31)P DOSY NMR measurements performed on saturated solutions containing crystalline {U32Pp16} show only trace amounts (∼2% relative abundance) of the intact form of this cluster, suggesting a complex interconversion of {U24Pp12}, {U32Pp16}, and {U4Pp4-x} ions.

  20. The secondary alkaline zinc electrode

    NASA Astrophysics Data System (ADS)

    McLarnon, Frank R.; Cairns, Elton J.

    1991-02-01

    The worldwide studies conducted between 1975 and 1990 with the aim of improving cell lifetimes of secondary alkaline zinc electrodes are overviewed. Attention is given the design features and characteristics of various secondary alkaline zinc cells, including four types of zinc/nickel oxide cell designs (vented static-electrolyte, sealed static-electrolyte, vibrating-electrode, and flowing-electrolyte); two types of zinc/air cells (mechanically rechargeable consolidated-electrode and mechanically rechargeable particulate-electrode); zinc/silver oxide battery; zinc/manganese dioxide cell; and zinc/ferric cyanide battery. Particular consideration is given to recent research in the fields of cell thermodynamics, zinc electrodeposition, zinc electrodissolution, zinc corrosion, electrolyte properties, mathematical and phenomenological models, osmotic pumping, nonuniform current distribution, and cell cycle-life perforamnce.

  1. Development of alkaline fuel cells.

    SciTech Connect

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  2. EQCM analysis of titanium corrosion in peroxide- or fluoride-containing solutions.

    PubMed

    Hattori, Masayuki; Oda, Yutaka

    2013-01-01

    Although offering superior resistance to corrosion, titanium is unable to withstand discoloration with exposure to peroxide or fluoride. The mechanism of this discoloration, however, remains to be clarified. The purpose of this study was to investigate the mechanism underlying discoloration of titanium with immersion in peroxide- or fluoride-containing solutions based on electrochemical quartz crystal microbalance (EQCM) analysis. A 9-MHz titanium-deposited quartz crystal was used as for the electrodes. Four test solutions were prepared for immersion of the electrodes: 154 mM (0.9%) NaCl; 150 mM H2O2+154 mM NaCl (pH=4 by addition of lactic acid); 150 mM H2O2+154 mM NaCl (pH=8 by addition of sodium hydroxide solution); and 48 mM (0.2%) NaF+154 mM NaCl (pH=5.0 by addition of lactic acid). A WinEchem electrochemistry software-controlled quartz crystal analyzer (QCA922) and the Potentiostat/Galvanostat (Princeton Applied Research) on Windows XP were used to measure concurrently the resonance frequency and potential of the electrodes. The EQCM data differed among solutions. In the acidulated fluoride-containing solution, the electrode showed lower open circuit potential and a gradual increase in electrode frequency, indicating a loss of mass by titanium dissolution. In the peroxide-containing solution, although open circuit potential showed no marked difference, electrode frequency showed a gentle decrease in acidic solution, indicating a gain in mass by oxidation; but an increase in alkaline solution, indicating a loss of mass by dissolution. These results confirmed that exposure to acidulated fluoride- or alkaline peroxide-containing solutions causes dissolution-induced discoloration, while that to acidulated peroxide-containing solutions resulted in the formation of an oxide film together with discoloration.

  3. Peroxides and peroxide-degrading enzymes in the thyroid.

    PubMed

    Schweizer, Ulrich; Chiu, Jazmin; Köhrle, Josef

    2008-09-01

    Iodination of thyroglobulin is the key step of thyroid hormone biosynthesis. It is catalyzed by thyroid peroxidase and occurs within the follicular space at the apical plasma membrane. Hydrogen peroxide produced by thyrocytes as an oxidant for iodide may compromise cellular and genomic integrity of the surrounding cells, unless these are sufficiently protected by peroxidases. Thus, peroxidases play two opposing roles in thyroid biology. Both aspects of peroxide biology in the thyroid are separated in space and time and respond to the different physiological states of the thyrocytes. Redox-protective peroxidases in the thyroid are peroxiredoxins, glutathione peroxidases, and catalase. Glutathione peroxidases are selenoenzymes, whereas selenium-independent peroxiredoxins are functionally linked to the selenoenzymes of the thioredoxin reductase family through their thioredoxin cofactors. Thus, selenium impacts directly and indirectly on protective enzymes in the thyroid, a link that has been supported by animal experiments and clinical observations. In view of this relationship, it is remarkable that rather little is known about selenoprotein expression and their potential functional roles in the thyroid. Moreover, selenium-dependent and -independent peroxidases have rarely been examined in the same studies. Therefore, we review the relevant literature and present expression data of both selenium-dependent and -independent peroxidases in the murine thyroid.

  4. REACTIONS OF SODIUM PEROXIDE WITH COMPONENTS OF LEGACY PLUTONIUM MATERIALS

    SciTech Connect

    Pierce, R.; Missimer, D.; Crowder, M.

    2011-10-04

    Plutonium oxide (PuO{sub 2}) calcined at >900 C resists dissolution in nitric acid (HNO{sub 3})-potassium fluoride (KF) solutions, a common method for their dissolution. The Savannah River National Laboratory (SRNL) has developed an alternate method for large samples of PuO{sub 2}-bearing materials using sodium peroxide (Na{sub 2}O{sub 2}) fusion as a pretreatment. The products of the reaction between Na{sub 2}O{sub 2} and PuO{sub 2} have been reported in the literature. As part of the SRNL development effort, additional data about the reaction between Na{sub 2}O{sub 2} and PuO{sub 2} were required. Also needed were data concerning the reaction of Na{sub 2}O{sub 2} with other components that may be present in the feed materials. Sodium peroxide was reacted with aluminum metal (Al), beryllium metal (Be), graphite, potassium chloride (KCl), magnesium chloride (MgCl{sub 2}), and calcium chloride (CaCl{sub 2}). The paper reports and discusses the reaction products of these and related compounds with Na{sub 2}O{sub 2}.

  5. Coating for components requiring hydrogen peroxide compatibility

    NASA Technical Reports Server (NTRS)

    Yousefiani, Ali (Inventor)

    2010-01-01

    The present invention provides a heretofore-unknown use for zirconium nitride as a hydrogen peroxide compatible protective coating that was discovered to be useful to protect components that catalyze the decomposition of hydrogen peroxide or corrode when exposed to hydrogen peroxide. A zirconium nitride coating of the invention may be applied to a variety of substrates (e.g., metals) using art-recognized techniques, such as plasma vapor deposition. The present invention further provides components and articles of manufacture having hydrogen peroxide compatibility, particularly components for use in aerospace and industrial manufacturing applications. The zirconium nitride barrier coating of the invention provides protection from corrosion by reaction with hydrogen peroxide, as well as prevention of hydrogen peroxide decomposition.

  6. Combined alkali and acid pretreatment of spent mushroom substrate for reducing sugar and biofertilizer production.

    PubMed

    Zhu, Hong-Ji; Liu, Jia-Heng; Sun, Li-Fan; Hu, Zong-Fu; Qiao, Jian-Jun

    2013-05-01

    Spent mushroom substrate (SMS) was pretreated with alkaline reagents including potassium hydroxide, lime and ammonia to enhance enzymatic saccharification. Under the best pretreatment conditions (1M KOH, 80 °C, 90 min; 1M lime, 80 °C, 120 min; 10 M ammonia, 70 °C, 120 min), the total reducing sugar (TRS) yield reached 258.6, 204.2 and 251.2 mg/g raw SMS, which were respectively 6.15, 4.86, and 5.98 times of untreated SMS. The effects of pretreatment by above alkaline reagents and sulfuric acid on the composition and structure of SMS were evaluated to provide comparative performance data. A new process, combined alkali and acid (CAA) pretreatment followed by enzymatic hydrolysis, was innovatively proposed to improve the cost-effectiveness and avoid environmental problems. The SMS residue after CAA pretreatment-enzymatic hydrolysis process was converted to biofertilizer with Pichia farinose FL7 and a cell density of 3.0×10(8) cfu/g in biomass was attained.

  7. Biomass pretreatment strategies via control of rheological behavior of biomass suspensions and reactive twin screw extrusion processing.

    PubMed

    Senturk-Ozer, Semra; Gevgilili, Halil; Kalyon, Dilhan M

    2011-10-01

    Twin screw extrusion based pretreatment of biomass is an attractive option due to its flexibility to carry out chemical reactions under relatively high stresses, temperatures and pressures. However, extrusion processes are rarely utilized in biomass pretreatment because such processing is constrained by rheological behavior of typical biomass suspensions. Without the manipulation of their rheological behavior, biomass suspensions become unprocessable within the extruder at modest biomass concentrations. Here it is demonstrated that gelation agents can render biomass suspensions processable. Specifically, carboxy methyl cellulose, CMC, could be used in conjunction with alkaline pretreatment of hardwood-type biomass and enabled separation of lignin from cellulose fibers. Furthermore, recycled black liquor, obtained upon pretreatment, was determined to be as effective as CMC for rendering biomass suspensions flowable by again facilitating the concomitant application of high shearing stresses and chemical treatment for the pretreatment of the biomass in the twin screw extruder.

  8. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2005-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  9. High Temperature Decomposition of Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydropemxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  10. Hydrogen peroxide on the surface of Europa.

    PubMed

    Carlson, R W; Anderson, M S; Johnson, R E; Smythe, W D; Hendrix, A R; Barth, C A; Soderblom, L A; Hansen, G B; McCord, T B; Dalton, J B; Clark, R N; Shirley, J H; Ocampo, A C; Matson, D L

    1999-03-26

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  11. Hydrogen peroxide on the surface of Europa

    USGS Publications Warehouse

    Carlson, R.W.; Anderson, M.S.; Johnson, R.E.; Smythe, W.D.; Hendrix, A.R.; Barth, C.A.; Soderblom, L.A.; Hansen, G.B.; McCord, T.B.; Dalton, J.B.; Clark, R.N.; Shirley, J.H.; Ocampo, A.C.; Matson, D.L.

    1999-01-01

    Spatially resolved infrared and ultraviolet wavelength spectra of Europa's leading, anti-jovian quadrant observed from the Galileo spacecraft show absorption features resulting from hydrogen peroxide. Comparisons with laboratory measurements indicate surface hydrogen peroxide concentrations of about 0.13 percent, by number, relative to water ice. The inferred abundance is consistent with radiolytic production of hydrogen peroxide by intense energetic particle bombardment and demonstrates that Europa's surface chemistry is dominated by radiolysis.

  12. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Benzoyl peroxide. 184.1157 Section 184.1157 Food... Specific Substances Affirmed as GRAS § 184.1157 Benzoyl peroxide. (a) Benzoyl peroxide ((C6H5CO)2O2, CAS Reg. No. 94-36-0) is a colorless, rhombic crystalline solid. It is prepared by reaction of...

  13. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Benzoyl peroxide. 184.1157 Section 184.1157 Food... GRAS § 184.1157 Benzoyl peroxide. (a) Benzoyl peroxide ((C6H5CO)2O2, CAS Reg. No. 94-36-0) is a colorless, rhombic crystalline solid. It is prepared by reaction of benzoyl chloride, sodium hydroxide,...

  14. 21 CFR 184.1157 - Benzoyl peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Benzoyl peroxide. 184.1157 Section 184.1157 Food... Specific Substances Affirmed as GRAS § 184.1157 Benzoyl peroxide. (a) Benzoyl peroxide ((C6H5CO)2O2, CAS Reg. No. 94-36-0) is a colorless, rhombic crystalline solid. It is prepared by reaction of...

  15. PEROXIDE PROCESS FOR SEPARATION OF RADIOACTIVE MATERIALS

    DOEpatents

    Seaborg, G.T.; Perlman, I.

    1958-09-16

    reduced state, from hexavalent uranium. It consists in treating an aqueous solution containing such uranium and plutonium ions with sulfate ions in order to form a soluble uranium sulfate complex and then treating the solution with a soluble thorium compound and a soluble peroxide compound in order to ferm a thorium peroxide carrier precipitate which carries down with it the plutonium peroxide present. During this treatment the pH of the solution must be maintained between 2 and 3.

  16. Oxidation of 1,1-dimethylhydrazine (UDMH) in aqueous solution with air and hydrogen peroxide.

    PubMed

    Lunn, G; Sansone, E B

    1994-10-01

    The degradation of 1,1-dimethylhydrazine (UDMH), a component of some rocket fuels, was investigated using atmospheric oxygen and hydrogen peroxide. The reactions were carried out in the presence and absence of copper catalysis and at varying pH. Reactions were also carried out in the presence of hydrazine, a constituent, along with UDMH, of the rocket fuel Aerozine-50. In the presence of copper, UDMH was degraded by air passed through the solution; the efficiency of degradation increased as the pH increased but the carcinogen N-nitrosodimethylamine (NDMA) was formed at neutral and alkaline pH. Oxidation was not seen in the absence of copper. Production of NDMA occurred even at copper concentrations of < 1 ppm. Oxidation of UDMH with hydrogen peroxide also gave rise to NDMA. When copper was absent degradation of UDMH did not occur at acid pH but when copper was present some degradation occurred at all pH levels investigated. The production of NDMA occurred mostly at neutral and alkaline pH. In general, higher concentrations of hydrogen peroxide and copper favored the production of NDMA. Dimethylamine, methanol, formaldehyde dimethylhydrazone, formaldehyde hydrazone, and tetramethyltetrazene were also produced. The last three compounds were tested and found to be mutagenic.

  17. Non-Chromate Aluminum Pretreatments

    DTIC Science & Technology

    2012-03-01

    and consisted of a mildly alkaline non-silicated cleaner, a hot phosphoric acid etch, a ferric sulfate/ nitric acid based de-smut, and finally the...steel surfaces, and an aerospace standard phosphoric acid deoxidizer with a mild, nitric - acid desmutter for surface preparation. The E1 vehicle was...OakiteTM brand chemicals, and consisted of a mildly alkaline non-silicated cleaner, a hot phosphoric acid etch, a ferric sulfate/ nitric acid based de-smut

  18. 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.

  19. The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process

    PubMed Central

    2012-01-01

    Background 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. PMID:22369467

  20. Temperature dependent surface electrochemistry on Pt singlecrystals in alkaline electrolyte: Part 3: The oxygen reductionreaction

    SciTech Connect

    tom.schmidt@psi.ch

    2002-08-01

    The kinetics of the oxygen reduction reaction (ORR) was studied in alkaline electrolyte at 293-333K on Pt(hkl) surfaces by means of the rotating ring-disk electrode technique with solution phase peroxide detected at the ring electrode. The ORR on Pt(hkl) was found to be highly structure sensitive with activities increasing in the sequence (111) > (100) > (110)(1x2). Very similar apparent activation energies (37-45 {+-} 5 kJmol-1, {eta} = 0.35 V) were found on all three surfaces. Furthermore, at elevated temperature, significantly smaller amounts of peroxide are formed in agreement with enhanced peroxide reduction rates by increasing temperature. We found that the Tafel slopes on all three single crystal surfaces decrease with increasing temperature, indicating that the logi-E relationship is not represented by a classical Butler-Volmer expression. Based on the kinetic analysis of the polarization curves and from simulations of logi-E curves, we propose that the rate of the ORR on Pt(hkl) in alkaline solution is mainly determined by the potential/temperature dependent surface coverage by OH{sub ad}. We propose two modes of action of the OH{sub ad}: (i) OH{sub ad} blocks the adsorption of O{sub 2} on active platinum sites; and (ii) OH{sub ad} alters the adsorption energy of intermediates which are formed during the ORR on Pt sites.

  1. Probing the heme iron coordination structure of alkaline chloroperoxidase.

    PubMed

    Blanke, S R; Martinis, S A; Sligar, S G; Hager, L P; Rux, J J; Dawson, J H

    1996-11-19

    The mechanism by which the heme-containing peroxidase, chloroperoxidase, is able to chlorinate substrates is poorly understood. One approach to advance our understanding of the mechanism of the enzyme is to determine those factors which contribute to its stability. In particular, under alkaline conditions, chloroperoxidase undergoes a transition to a new, spectrally distinct form, with accompanying loss of enzymatic activity. In the present investigation, ferric and ferrous alkaline chloroperoxidase (C420) have been characterized by electronic absorption, magnetic circular dichroism, and electron paramagnetic resonance spectroscopy. The heme iron oxidation state influences the transition to C420; the pKa for the alkaline transition is 7.5 for the ferric protein and 9.5 for the ferrous protein. The five-coordinate, high-spin ferric native protein converts to a six-coordinate low-spin species (C420) as the pH is raised above 7.5. The inability of ferric C420 to bind exogenous ligands, as well as the dramatically increased reactivity of the proximal Cys29 heme ligand toward modification by the sulfhydryl reagent p-mercuribenzoate, suggests that a conformational change has occurred during conversion to C420 that restricts access to the peroxide binding site while increasing the accessibility of Cys29. However, it does appear that Cys29-derived ligation is at least partially retained by ferric C420, potentially in a thiolate/imidazole coordination sphere. Ferrous C420, on the other hand, appears not to possess a thiolate ligand but instead likely has a bis-imidazole (histidine) coordination structure. The axial ligand trans to carbon monoxide in ferrous-CO C420 may be a histidine imidazole. Since chloroperoxidase functions normally through the ferric and higher oxidation states, the fact that the proximal thiolate ligand is largely retained in ferric C420 clearly indicates that additional factors such as the absence of a vacant sixth coordination site sufficiently

  2. Chemiluminescence behavior of CdTe-hydrogen peroxide enhanced by sodium hypochlorite and sensitized sensing of estrogens

    NASA Astrophysics Data System (ADS)

    Ling, Bo; Bi, Jianhong; Pi, Zongxin; Dong, Huaze; Dong, Ling

    2014-05-01

    It has been found that sodium hypochlorite enhanced the chemiluminescence (CL) of the CdTe nanocrystal (NC)-hydrogen peroxide system and that estrogens inhibited these CL signals in alkaline solution. CL spectra were used to investigate the mechanism of the CL enhancement. On the basis of the inhibition, a flow-injection CL method has been established for determination of three natural estrogens.

  3. Diclofenac salts. III. Alkaline and earth alkaline salts.

    PubMed

    Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa

    2005-11-01

    Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.

  4. Steam pretreatment for coal liquefaction

    SciTech Connect

    Graff, R.A.; Balogh-Nair, V.

    1991-01-01

    Steam pretreatment is the reaction of coal with steam at temperatures well below those usually used for solubilization. The objective of the proposed work is to test the application of steam pretreatment to coal liquefaction. This quarter, a 300 ml stirred autoclave for liquefaction tests was received and installation initiated. Four coal samples were obtained from the Penn State Sample Bank. Continuous flow pretreatment procedures were reestablished. Extraction yields after pretreatment of the new sample of Illinois No. 6 coal are in agreement with previous results even though the particle size is considerably larger. Purification of the model compound {beta}-naphthylmethyl phenyl ether has been completed. However, {alpha}-naphthylmethyl phenyl ether has been found to undergo acid catalyzed rearrangement during purification on silica. An alternative method for purification is being examined. 4 refs., 3 figs., 1 tab.

  5. Cellulose pretreatments of lignocellulosic substrates

    NASA Technical Reports Server (NTRS)

    Weil, J.; Westgate, P.; Kohlmann, K.; Ladisch, M. R.; Mitchell, C. A. (Principal Investigator)

    1994-01-01

    Cellulose in inedible plant materials, forestry residues, and municipal wastes must be pretreated to disrupt its physical structure, thereby making its hydrolysis to glucose practical. Developments since 1991 are summarized.

  6. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  7. High conversion of sugarcane bagasse into monosaccharides based on sodium hydroxide pretreatment at low water consumption and wastewater generation.

    PubMed

    Wang, Wen; Wang, Qiong; Tan, Xuesong; Qi, Wei; Yu, Qiang; Zhou, Guixiong; Zhuang, Xinshu; Yuan, Zhenhong

    2016-10-01

    The generation of a great quantity of black liquor (BL) and waste wash water (WWW) has been key problems of the alkaline pretreatment. This work tried to build a sustainable way to recycle the BL for pretreating sugarcane bagasse (SCB) and the WWW for washing the residual solid (RS) of alkali-treated SCB which would be subsequently hydrolysed and fermented. The enzymatic hydrolysis efficiency of the washed RS decreased with the recycling times of BL and WWW increasing. Tween80 at the loading of 0.25% (V/V) could notably improve the enzymatic hydrolysis and had no negative impact on the downstream fermentation. Compared with the non-recycling and BL recycling ways based on alkaline pretreatment, the BL-WWW recycling way could not only maintain high conversion of carbohydrate into monosaccharides and save alkali amount of 45.5%, but also save more than 80% water and generate less than 15% waste water.

  8. [Nitric oxide and lipid peroxidation].

    PubMed

    Cristol, J P; Maggi, M F; Guérin, M C; Torreilles, J; Descomps, B

    1995-01-01

    Nitric oxide (NO) is a free radical produced enzymatically in biological systems from the guanidino group of L-arginine. Its large spectrum of biological effects is achieved through chemical interactions with different targets including oxygen (O2), superoxide (O2o-) and other oxygen reactive species (ROS), transition metals and thiols. Superoxide anions and other ROS have been reported to react with NO to produce peroxynitrite anions that can decompose to form nitrogen dioxide (NO2) and hydroxyl radial (OHo). Thus, NO has been reported to have a dual effect on lipid peroxidation (prooxidant via the peroxynitrite or antioxydant via the chelation of ROS). In the present study we have investigated in different models the in vitro and in vivo action of NO on lipid peroxidation. Copper-induced LDL oxidation were used as an in vitro model. Human LDL (100 micrograms ApoB/ml) were incubated in oxygene-saturated PBS buffer in presence or absence of Cu2+ (2.5 microM) with increasing concentrations of NO donnors (sodium nitroprussiate or nitroso-glutathione). LDL oxidation was monitored continuously for conjugated diene formation (234 nm) and 4-hydroxynonenal (HNE) accumulation. Exogenous NO prevents in a dose dependent manner the progress of copper-induced oxidation. Ischaemia-reperfusion injury (I/R), characterized by an overproduction of ROS, is used as an in vivo model. Anaesthetized rats were submitted to 1 hour renal ischaemia following by 2 hours of reperfusion. Sham-operated rats (SOP) were used as control. Lipid peroxidation was evaluated by measuring the HNE accumulated in rats kidneys in presence or absence of L-arginine or D-arginine infusion. L-arginine, but not D-arginine, enhances HNE accumulation in I/R but not in SOP (< 0.050 pmol/g tissue in SOP versus 0.6 nmol/g tissue in I/R), showing that, in this experimental conditions, NO produced from L-arginine, enhances the toxicity of ROS. This study shows that the pro- or antioxydant effects of NO are different

  9. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  10. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  11. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  12. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  13. 7 CFR 58.431 - Hydrogen peroxide.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Hydrogen peroxide. 58.431 Section 58.431 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.431 Hydrogen peroxide. The solution shall comply with the specification of the...

  14. Molecular Association and Structure of Hydrogen Peroxide.

    ERIC Educational Resources Information Center

    Giguere, Paul A.

    1983-01-01

    The statement is sometimes made in textbooks that liquid hydrogen peroxide is more strongly associated than water, evidenced by its higher boiling point and greater heat of vaporization. Discusses these and an additional factor (the nearly double molecular mass of the peroxide), focusing on hydrogen bonds and structure of the molecule. (JN)

  15. Fundamentals of ISCO Using Hydrogen Peroxide

    EPA Science Inventory

    Hydrogen peroxide is a common oxidant that has been applied extensively with in situ chemical oxidation (ISCO). Because of its widespread use in this and other fields, it has been extensively researched. This research has revealed that hydrogen peroxide has very complex chemistry...

  16. [Advances in peroxide-based decontaminating technologies].

    PubMed

    Xi, Hai-ling; Zhao, San-ping; Zhou, Wen

    2013-05-01

    With the boosting demand for eco-friendly decontaminants, great achievements in peroxide-based decontaminating technologies have been made in recent years. These technologies have been applied in countering chemical/biological terrorist attacks, dealing with chemical/biological disasters and destructing environmental pollutants. Recent research advances in alpha-nucleophilic/oxidative reaction mechanisms of peroxide-based decontamination against chemical warfare agents were reviewed, and some classical peroxide-based decontaminants such as aqueous decontaminating solution, decontaminating foam, decontaminating emulsions, decontaminating gels, decontaminating vapors, and some newly developed decontaminating media (e.g., peroxide-based self-decontaminating materials and heterogeneous nano-catalytic decontamination systems) were introduced. However, currently available peroxide-based decontaminants still have some deficiencies. For example, their decontamination efficiencies are not as high as those of chlorine-containing decontaminants, and some peroxide-based decontaminants show relatively poor effect against certain agents. More study on the mechanisms of peroxide-based decontaminants and the interfacial interactions in heterogeneous decontamination media is suggested. New catalysts, multifunctional surfactants, self-decontaminating materials and corrosion preventing technologies should be developed before peroxide-based decontaminants really become true "green" decontaminants.

  17. Simple, field portable colorimetric detection device for organic peroxides and hydrogen peroxide

    DOEpatents

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie; Reynolds, John G.; Nunes, Peter; Shields, Sharon J.

    2010-11-09

    A simple and effective system for the colorimetric determination of organic peroxides and hydrogen peroxide. A peroxide pen utilizing a swipe material attached to a polyethylene tube contains two crushable vials. The two crushable vials contain a colorimetric reagent separated into dry ingredients and liquid ingredients. After swiping a suspected substance or surface the vials are broken, the reagent is mixed thoroughly and the reagent is allowed to wick into the swipe material. The presence of organic peroxides or hydrogen peroxide is confirmed by a deep blue color.

  18. Processes for pretreating lignocellulosic biomass: A review

    SciTech Connect

    McMillan, J D

    1992-11-01

    This paper reviews existing and proposed pretreatment processes for biomass. The focus is on the mechanisms by which the various pretreatments act and the influence of biomass structure and composition on the efficacy of particular pretreatment techniques. This analysis is used to identify pretreatment technologies and issues that warrant further research.

  19. Alkaline detergent recycling via ultrafiltration

    SciTech Connect

    Steffani, C.; Meltzer, M.

    1995-06-01

    The metal finishing industry uses alkaline cleaners and detergents to remove oils and dirt from manufactured parts, often before they are painted or plated. The use of these cleaners has grown because environmental regulations are phasing out ozone depleting substances and placing restrictions on the use and disposal of many hazardous solvents. Lawrence Livermore National Laboratory is examining ultrafiltration as a cleaning approach that reclaims the cleaning solutions and minimizes wastes. The ultrafiltration membrane is made from sheets of polymerized organic film. The sheets are rolled onto a supporting frame and installed in a tube. Spent cleaning solution is pumped into a filter chamber and filtered through the membrane that captures oils and dirt and allows water and detergent to pass. The membrane is monitored and when pressure builds from oil and dirt, an automatic system cleans the surface to maintain solution flow and filtration quality. The results show that the ultrafiltration does not disturb the detergent concentration or alkalinity but removed almost all the oils and dirt leaving the solution in condition to be reused.

  20. Probiotics ameliorate the hydrogen peroxide-induced epithelial barrier disruption by a PKC- and MAP kinase-dependent mechanism

    PubMed Central

    Seth, A.; Yan, Fang; Polk, D.Brent; Rao, R. K.

    2009-01-01

    Probiotics promote intestinal epithelial integrity and reduce infection and diarrhea. We evaluated the effect of Lactobacillus rhamnosus GG-produced soluble proteins (p40 and p75) on the hydrogen peroxide-induced disruption of tight junctions and barrier function in Caco-2 cell monolayers. Pretreatment of cell monolayers with p40 or p75 attenuated the hydrogen peroxide-induced decrease in transepithelial resistance and increase in inulin permeability in a time- and dose-dependent manner. p40 and p75 also prevented hydrogen peroxide-induced redistribution of occludin, ZO-1, E-cadherin, and β-catenin from the intercellular junctions and their dissociation from the detergent-insoluble fractions. Both p40 and p75 induced a rapid increase in the membrane translocation of PKCβI and PKCε. The attenuation of hydrogen peroxide-induced inulin permeability and redistribution of tight junction proteins by p40 and p75 was abrogated by Ro-32-0432, a PKC inhibitor. p40 and p75 also rapidly increased the levels of phospho-ERK1/2 in the detergent-insoluble fractions. U0126 (a MAP kinase inhibitor) attenuated the p40- and p75-mediated reduction of hydrogen peroxide-induced tight junction disruption and inulin permeability. These studies demonstrate that probiotic-secretory proteins protect the intestinal epithelial tight junctions and the barrier function from hydrogen peroxide-induced insult by a PKC- and MAP kinase-dependent mechanism. PMID:18292183

  1. Probiotics ameliorate the hydrogen peroxide-induced epithelial barrier disruption by a PKC- and MAP kinase-dependent mechanism.

    PubMed

    Seth, A; Yan, Fang; Polk, D Brent; Rao, R K

    2008-04-01

    Probiotics promote intestinal epithelial integrity and reduce infection and diarrhea. We evaluated the effect of Lactobacillus rhamnosus GG-produced soluble proteins (p40 and p75) on the hydrogen peroxide-induced disruption of tight junctions and barrier function in Caco-2 cell monolayers. Pretreatment of cell monolayers with p40 or p75 attenuated the hydrogen peroxide-induced decrease in transepithelial resistance and increase in inulin permeability in a time- and dose-dependent manner. p40 and p75 also prevented hydrogen peroxide-induced redistribution of occludin, ZO-1, E-cadherin, and beta-catenin from the intercellular junctions and their dissociation from the detergent-insoluble fractions. Both p40 and p75 induced a rapid increase in the membrane translocation of PKCbetaI and PKCepsilon. The attenuation of hydrogen peroxide-induced inulin permeability and redistribution of tight junction proteins by p40 and p75 was abrogated by Ro-32-0432, a PKC inhibitor. p40 and p75 also rapidly increased the levels of phospho-ERK1/2 in the detergent-insoluble fractions. U0126 (a MAP kinase inhibitor) attenuated the p40- and p75-mediated reduction of hydrogen peroxide-induced tight junction disruption and inulin permeability. These studies demonstrate that probiotic-secretory proteins protect the intestinal epithelial tight junctions and the barrier function from hydrogen peroxide-induced insult by a PKC- and MAP kinase-dependent mechanism.

  2. Rearrangements of organic peroxides and related processes

    PubMed Central

    Yaremenko, Ivan A; Vil’, Vera A; Demchuk, Dmitry V

    2016-01-01

    Summary This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately. PMID:27559418

  3. Hydrogen peroxide treatment of TCE contaminated soil

    SciTech Connect

    Hurst, D.H.; Robinson, K.G.; Siegrist, R.L.

    1993-12-31

    Solvent contaminated soils are ubiquitous in the industrial world and represent a significant environmental hazard due to their persistence and potentially negative impacts on human health and the environment. Environmental regulations favor treatment of soils with options which reduce the volume and toxicity of contaminants in place. One such treatment option is the in-situ application of hydrogen peroxide to soils contaminated with chlorinated solvents such as trichloroethylene (TCE). This study investigated hydrogen peroxide mass loading rates on removal of TCE from soils of varying organic matter content. Batch experiments conducted on contaminated loam samples using GC headspace analysis showed up to 80% TCE removal upon peroxide treatment. Column experiments conducted on sandy loam soils with high organic matter content showed only 25% TCE removal, even at hydrogen peroxide additions of 25 g peroxide per kg soil.

  4. Rearrangements of organic peroxides and related processes.

    PubMed

    Yaremenko, Ivan A; Vil', Vera A; Demchuk, Dmitry V; Terent'ev, Alexander O

    2016-01-01

    This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O-O-bond cleavage. Detailed information about the Baeyer-Villiger, Criegee, Hock, Kornblum-DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately.

  5. Vapor Hydrogen Peroxide Sterilization Certification

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Chung, Shirley; Barengoltz, Jack

    For interplanetary missions landing on a planet of potential biological interest, United States NASA planetary protection currently requires that the flight system must be assembled, tested and ultimately launched with the intent of minimizing the bioload taken to and deposited on the planet. Currently the only NASA approved microbial reduction method is dry heat sterilization process. However, with utilization of such elements as highly sophisticated electronics and sensors in modern spacecraft, this process presents significant materials challenges and is thus an undesirable bioburden reduction method to design engineers. The objective of this work is to introduce vapor hydrogen peroxide (VHP) as an alternative to dry heat microbial reduction to meet planetary protection requirements. The VHP sterilization technology is widely used by the medical industry, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal of our study is determine the minimum VHP process conditions for PP acceptable microbial reduction levels. A series of experiments were conducted using Geobacillus stearothermophilus to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters -hydrogen peroxide concentration, number of pulses, and exposure duration -the investigation also considered the possible effect of environmental pa-rameters. Temperature, relative humidity, and material substrate effects on lethality were also studied. Based on the results, a most conservative D value was recommended. This recom-mended D value was also validated using VHP "hardy" strains that were isolated from clean-rooms and environmental populations collected from spacecraft relevant areas. The efficiency of VHP at ambient condition as well as VHP material compatibility will also be

  6. DNA polymerase III requirement for repair of DNA damage caused by methyl methanesulfonate and hydrogen peroxide

    SciTech Connect

    Hagensee, M.E.; Bryan, S.K.; Moses, R.E.

    1987-10-01

    The pcbA1 mutation allows DNA replication dependent on DNA polymerase I at the restrictive temperature in polC(Ts) strains. Cells which carry pcbA1, a functional DNA polymerase I, and a temperature-sensitive DNA polymerase III gene were used to study the role of DNA polymerase III in DNA repair. At the restrictive temperature for DNA polymerase III, these strains were more sensitive to the alkylating agent methyl methanesulfonate (MMS) and hydrogen peroxide than normal cells. The same strains showed no increase in sensitivity to bleomycin, UV light, or psoralen at the restrictive temperature. The sensitivity of these strains to MMS and hydrogen peroxide was not due to the pcbAl allele, and normal sensitivity was restored by the introduction of a chromosomal or cloned DNA polymerase III gene, verifying that the sensitivity was due to loss of DNA polymerase III alpha-subunit activity. A functional DNA polymerase III is required for the reformation of high-molecular-weight DNA after treatment of cells with MMS or hydrogen peroxide, as demonstrated by alkaline sucrose sedimentation results. Thus, it appears that a functional DNA polymerase III is required for the optimal repair of DNA damage by MMS or hydrogen peroxide.

  7. [Carbamide peroxide as source of hydrogen peroxide for the luminol application at crime scenes].

    PubMed

    Schwarz, Lothar; Hermanowski, Mona-Lena

    2009-01-01

    The solution of hydrogen peroxide is a critical ingredient of the Weber luminol application for blood detection at the crime scene. An ideal alternative to the unstable hydrogen peroxide is a solid compound which is easy to transport, stable and quick to solve in water at the crime scene. Carbamide peroxide (urea peroxide) is one of these solid hydrogen peroxide carriers which is easy to obtain as one gram tablets. At dry conditions it is stable over a long period at room temperature and even for a short time at higher temperatures. But at 70 degrees C (180 degrees F) the tablets go out of shape and cake after one hour. In the application of luminol there are no differences between the use of hydrogen peroxide and carbamide peroxide.

  8. Alkaline and alkaline earth metal phosphate halides and phosphors

    DOEpatents

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  9. Effect of steam explosion and enzymatic pre-treatments on pulping and bleaching of Hesperaloe funifera.

    PubMed

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

    2012-05-01

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

  10. Infiltration of natural caries lesions in relation to their activity status and acid pretreatment in vitro.

    PubMed

    Neuhaus, K W; Schlafer, S; Lussi, A; Nyvad, B

    2013-01-01

    This study aimed at testing how active and inactive enamel caries lesions differ by their degree of resin infiltration, and whether the choice of acid pretreatment plays a crucial role. Four examiners assessed 104 human molars and premolars with noncavitated enamel lesions and classified them as 'active' or 'inactive' using the Nyvad criteria. Forty-five teeth were included in this study after independent unanimous lesion activity assessment. Lesions were cut perpendicularly into 2 halves. Each half lesion was pretreated with either 15% hydrochloric acid or 35% phosphoric acid. The lesions were infiltrated after staining with rhodamine isothiocyanate. Thin sections of 100 µm were prepared and the specimens were bleached with 30% hydrogen peroxide. The specimens were then counterstained with sodium fluorescein, subjected to confocal laser scanning microscopy and analyzed quantitatively. Outcome parameters were maximum and average infiltration depths as well as relative penetration depths and areas. In active lesions no significant difference of percentage maximum penetration depth and percentage average penetration depth between lesions pretreated with hydrochloric or phosphoric acid could be observed. In inactive lesions, however, phosphoric acid pretreatment resulted in significantly lower penetration compared to hydrochloric acid pretreatment. Surface conditioning with hydrochloric acid led to similar infiltration results in active and inactive lesions. Moreover, inactive lesions showed greater variability in all assessed infiltration parameters than did active lesions. In conclusion, caries lesion activity and acid pretreatment both influenced the infiltration. The use of phosphoric acid to increase permeability of the surface layer of active lesions should be further explored.

  11. Electrochemical and spectroscopic studies of ssDNA damage induced by hydrogen peroxide using graphene based nanomaterials.

    PubMed

    Berghian-Grosan, Camelia; Biris, Alexandru Radu; Coros, Maria; Pogacean, Florina; Pruneanu, Stela

    2015-06-01

    The oxidative damage of deoxyribonucleic acid (DNA) has been intensively studied due to its role in the occurrence of some diseases. The hydrogen peroxide (H2O2) is one of the reactive oxygen species (ROS). It can induce oxidation of DNA bases, sugar lesions or DNA strand breaks. The Pt/Gr-Au-3 modified electrode was employed for the analysis of four ssDNA samples: single-stranded DNA (ssDNA), ssDNA pre-treated with hydrogen peroxide (ssDNA-H2O2), ssDNA pre-treated with graphene-gold nanoparticles (ssDNA-Gr-Au) and ssDNA-Gr-Au complex pre-treated with hydrogen peroxide (ssDNA-Gr-Au-H2O2). By monitoring the changes of the purine oxidation peaks currents, we obtained valuable information about the damage induced by the hydrogen peroxide onto the un-treated or graphene pre-treated ssDNA and also about the interaction between ssDNA and graphene-based nanomaterial. The FTIR analysis has been also used to obtain information about the ssDNA damage. These findings allowed us to prove the utility of graphene-based nanomaterials (mainly Gr-Au-3) not only for the investigation of the oxidative damage induced by a non-radical oxidant, but also for the determination of the type of interaction between ssDNA and graphene surface. The stability of the ssDNA-Gr-Au-3 complex against the damage induced by H2O2, in the absence of reduced transition metals, was also established.

  12. Improved volatile fatty acids anaerobic production from waste activated sludge by pH regulation: Alkaline or neutral pH?

    PubMed

    Ma, Huijun; Chen, Xingchun; Liu, He; Liu, Hongbo; Fu, Bo

    2016-02-01

    In this study, the anaerobic fermentation was carried out for volatile fatty acids (VFAs) production at different pH (between 7.0 and 10.0) conditions with untreated sludge and heat-alkaline pretreated waste activated sludge. In the fermentation with untreated sludge, the extent of hydrolysis of organic matters and extent of acidification at alkaline pH are 54.37% and 30.37%, respectively, resulting in the highest VFAs yield at 235.46mg COD/gVS of three pH conditions. In the fermentation with heat-alkaline pretreated sludge, the acidification rate and VFAs yield at neutral pH are 30.98% and 240.14mg COD/gVS, respectively, which are higher than that at other pH conditions. With the glucose or bovine serum albumin as substrate for VFAs production, the neutral pH showed a higher VFAs concentration than the alkaline pH condition. The results of terminal restriction fragment length polymorphism (T-RFLP) analysis indicated that the alkaline pH caused low microbial richness. Based on the results in this study, we demonstrated that the alkaline pH is favor of hydrolysis of organic matter in sludge while neutral pH improved the acidogenesis for the VFAs production from sludge. Our finding is obvious different to the previous research and helpful for the understanding of how heat-alkaline pretreatment and alkaline fermentation influence the VFAs production, and beneficial to the development of VFAs production process.

  13. The roles of peroxide protective regulons in protecting Xanthomonas campestris pv. campestris from sodium hypochlorite stress.

    PubMed

    Charoenlap, Nisanart; Sornchuer, Phornphan; Piwkam, Anong; Srijaruskul, Kriangsuk; Mongkolsuk, Skorn; Vattanaviboon, Paiboon

    2015-05-01

    The exposure of Xanthomonas campestris pv. campestris to sublethal concentrations of a sodium hypochlorite (NaOCl) solution induced the expression of genes that encode peroxide scavenging enzymes within the OxyR and OhrR regulons. Sensitivity testing in various X. campestris mutants indicated that oxyR, katA, katG, ahpC, and ohr contributed to protection against NaOCl killing. The pretreatment of X. campestris cultures with oxidants, such as hydrogen peroxide (H2O2), t-butyl hydroperoxide, and the superoxide generator menadione, protected the bacteria from lethal concentrations of NaOCl in an OxyR-dependent manner. Treating the bacteria with a low concentration of NaOCl resulted in the adaptive protection from NaOCl killing and also provided cross-protection from H2O2 killing. Taken together, the results suggest that the toxicity of NaOCl is partially mediated by the generation of peroxides and other reactive oxygen species that are removed by primary peroxide scavenging enzymes, such as catalases and AhpC, as a part of an overall strategy that protects the bacteria from the lethal effects of NaOCl.

  14. Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

    PubMed Central

    Taherzadeh, Mohammad J.; Karimi, Keikhosro

    2008-01-01

    Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pretreatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. The present work is dedicated to reviewing the methods that have been studied for pretreatment of lignocellulosic wastes for conversion to ethanol or biogas. Effective parameters in pretreatment of lignocelluloses, such as crystallinity, accessible surface area, and protection by lignin and hemicellulose are described first. Then, several pretreatment methods are discussed and their effects on improvement in ethanol and/or biogas production are described. They include milling, irradiation, microwave, steam explosion, ammonia fiber explosion (AFEX), supercritical CO2 and its explosion, alkaline hydrolysis, liquid hot-water pretreatment, organosolv processes, wet oxidation, ozonolysis, dilute-and concentrated-acid hydrolyses, and biological pretreatments. PMID:19325822

  15. Pre-treatment of wastewater sludge--biodegradability and rheology study.

    PubMed

    Verma, M; Brar, Satinder K; Riopel, A R; Tyagi, R D; Surampalli, R Y

    2007-03-01

    This study investigates the changes in biodegradability, rheology and metal concentration of wastewater sludge--non-hydrolyzed (raw), sterilized, and hydrolyzed (thermal alkaline pre-treatment) at total solids concentration from 10-50 g l(-1) to ascertain the bioavailability of nutrients for subsequent fermentation. The dissolved solids concentration increased linearly with total solids. Irrespective of the wastewater sludge (raw or, pre-treated), percentage biodegradability in terms of total solids (26.5-44.5%), total COD (25.8-56.5%) and dissolved solids (41.9-66.9%) was maximum around 20 g l(-1) solids concentration. The pseudoplasticity of sludge decreased (consistency index decreased from 895.1 to 5.2 and flow behaviour index increased from 0.28 to 0.88, for all sludge types) with pre-treatment and increased with total solids concentration. The pre-treated sludge, namely, sterilized and hydrolyzed sludge showed higher microbial growth (1-2 log cycles increase in comparison to raw sludge) suggesting their susceptibility to microbial degradation. The C:N ratio decreased with pre-treatment (raw sludge > sterilized > hydrolyzed) during biodegradation. Although the metal concentration increased in incubated hydrolyzed sludge, the final concentration was within the regulatory norms for agriculture application. Thus, pretreatment of sludge resulted in increase in biodegradability making it an excellent proponent for fermented value-added products.

  16. Pretreatment of corn stover for sugar production with switchgrass-derived black liquor.

    PubMed

    Xu, Jiele; Zhang, Ximing; Cheng, Jay J

    2012-05-01

    To improve the cost-effectiveness of biomass-to-sugar conversion, sodium hydroxide (NaOH) pretreatment of switchgrass was carried out at 21°C using previously determined optimum conditions (2% NaOH (w/v), 6h), and the spent alkaline liquid (black liquor) was collected and used for pretreatment of corn stover, a feedstock exhibiting a higher susceptibility to NaOH attack, for improved enzymatic hydrolysis at a reduced cost. The results showed that, because of the high pH and the appreciable amount of carbohydrates in the black liquor, sugar production during enzymatic hydrolysis of corn stover pretreated with black liquor was comparable to that of biomass pretreated with 1% NaOH. After black liquor pretreatment at the best residence time (24h), the total reducing sugar, glucose, and xylose yields of corn stover reached 478.5, 287.7, and 145.3mg/g raw biomass, respectively, indicating the viability of this novel pretreatment technology.

  17. Closed type alkaline storage battery

    SciTech Connect

    Hayama, H.

    1980-06-10

    The alkaline storage battery employs a metallic hat shaped terminal closure which has a piercing needle as well as a puncturable metallic diaphragm positioned below the piercing needle. The needle is fixed by caulking at its peripheral edge portion to a edge of the closure. A comparatively thick and hard metal plate is placed on the inner surface of the diaphragm and is applied to an open portion of a tubular metallic container which has a battery element. A peripheral edge portion of the closure, the diaphragm and the metallic plate are clamped in airtight relationship through a packing between the caulked end portion and an inner annular step portion of the metallic container of the battery. A lead wire extends from one polarity electrode of the battery element and is connected to a central portion of the metallic plate.

  18. Microcalorimetric Measurements of Hydrogen Peroxide Stability

    NASA Technical Reports Server (NTRS)

    Davis, Dennis D.; Hornung, Steven D.; Baker, Dave L.

    1999-01-01

    Recent interest in propellants with nontoxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because hydrogen peroxide is sensitive to contaminants and materials interactions, stability and shelf life are issues. A relatively new, ultrasensitive heat measurement technique, isothermal microcalorimetry, is being used at the White Sands Test Facility to monitor the decomposition of hydrogen peroxide at near ambient temperatures. Isothermal microcalorimetry measures the beat flow from a reaction vessel into a surrounding heat sink. In these applications, microcalorimetry is approximately 1,000 times more sensitive than accelerating rate calorimetry or differential scanning calorimetry for measuring thermal events. Experimental procedures have been developed for the microcalorimetric measurement of the ultra-small beat effects caused by incompatible interactions of hydrogen peroxide. The decomposition rates of hydrogen peroxide at the picomole/sec/gram level have been measured showing the effects of stabilizers and peroxide concentration. Typical measurements are carried out at 40 C over a 24-hour period, This paper describes a method for the conversion of the heat flow measurements to chemical reaction rates based on thermochemical considerations. The reaction rates are used in a study of the effects of stabilizer levels on the decomposition of propellant grade hydrogen peroxide.

  19. [Indices of oxidative stress. 2. Lipid peroxides].

    PubMed

    Lushchak, V I; Bahniukova, T V; Luzhna, L I

    2006-01-01

    Two methods of the determination of lipid peroxidation products have been compared which are based on Fe(II) oxidation by them at acid pH values in the presence of xylenol orange which binds Fe(III) have been compared. The first method uses cumene hydropeoxide as an internal standard. In the second one, lipid peroxides are previously reduced by triphenylphosphine and these substances content is measured as a difference of the production of complexes with xylenol orange and iron ions in the control (with reduction) and experimental sample (without reduction). The optimization of measurement conditions is described. The levels of lipid peroxides in goldfish tissues assayed simultaneously by two methods were similar. The method with cumene hydroperoxide needs less amounts of biological material; moreover, there is no necessity in a calibration curve. Effects of hyperoxia on lipid peroxide levels in goldfish tissues were studied with the cumene method. Within the first hours of hyperoxia this index increased 13-times in the liver and 2-times in the brain and muscle. The further exposure rebounded this parameter to the initial level. Levels of lipid peroxides positively correlated with levels of end products of lipid peroxidation (thiobarbiturate acid reactive substances) in the goldfish tissues. The method of quantification of lipid peroxides with cumene is recommended for wide using in biological investigations.

  20. A combined sodium phosphate and sodium sulfide pretreatment for enhanced enzymatic digestibility and delignification of corn stover.

    PubMed

    Qing, Qing; Zhou, Linlin; Guo, Qi; Huang, Meizi; He, Yucai; Wang, Liqun; Zhang, Yue

    2016-10-01

    Na3PO4 and Na2S were employed as efficient alkaline catalysts for the pretreatment of corn stover. To systematically obtain optimal conditions, the effects of critical pretreatment parameters including sodium phosphate concentration (1-4%), sulfidity (0-20%), pretreatment temperature (100-120°C), and reaction time (20-60min) on the reducing sugar yield of pretreated substrates were evaluated in a lab-scale using the response surface methodology. Pretreated under the sodium phosphate concentration of 4%, sulfidity of 10%, temperature of 120°C, and reaction time of 40min, the reducing sugar yield and glucose yield of the pretreated corn stover achieved 91.11% and 64.01%, respectively, with a moderate enzyme loading of 30FPU/g substrate. Additionally, a strong correlation (R(2)=0.971 and R(2)=0.954) between the delignification and the reducing sugar yield (or glucose yield) was observed by this pretreatment method. These results evidently support that the combined Na3PO4-Na2S pretreatment is an effective and feasible method for processing lignocellulosic biomass.

  1. Towards a metagenomic understanding on enhanced biomethane production from waste activated sludge after pH 10 pretreatment

    PubMed Central

    2013-01-01

    Background Understanding the effects of pretreatment on anaerobic digestion of sludge waste from wastewater treatment plants is becoming increasingly important, as impetus moves towards the utilization of sludge for renewable energy production. Although the field of sludge pretreatment has progressed significantly over the past decade, critical questions concerning the underlying microbial interactions remain unanswered. In this study, a metagenomic approach was adopted to investigate the microbial composition and gene content contributing to enhanced biogas production from sludge subjected to a novel pretreatment method (maintaining pH at 10 for 8 days) compared to other documented methods (ultrasonic, thermal and thermal-alkaline). Results Our results showed that pretreated sludge attained a maximum methane yield approximately 4-fold higher than that of the blank un-pretreated sludge set-up at day 17. Both the microbial and metabolic consortium shifted extensively towards enhanced biodegradation subsequent to pretreatment, providing insight for the enhanced methane yield. The prevalence of Methanosaeta thermophila and Methanothermobacter thermautotrophicus, together with the functional affiliation of enzymes-encoding genes suggested an acetoclastic and hydrogenotrophic methanogenesis pathway. Additionally, an alternative enzymology in Methanosaeta was observed. Conclusions This study is the first to provide a microbiological understanding of improved biogas production subsequent to a novel waste sludge pretreatment method. The knowledge garnered will assist the design of more efficient pretreatment methods for biogas production in the future. PMID:23506434

  2. [Impacts of alkaline thermal treatment on characteristics of sludge from sewage treatment plant].

    PubMed

    Yang, Shi-Dong; Chen, Xia; Liu, Cao; Xiao, Ben-Yi

    2015-02-01

    Alkaline thermal treatment is an important pretreatment method for sewage sludge. In this paper, in order to optimize the alkaline thermal treatment conditions for sludge pretreatment, four pretreatment parameters ( sludge concentration, pH, temperature and treatment time) were investigated through orthogonal experiments to determine their effects on the sludge disintegration, sludge concentration and sludge morphology of sewage sludge. The experimental results showed that the significance of the four factors on sludge characteristics was in the order of pH > temperature > treatment time > sludge concentration. Additionally, the optimal conditions of the four factors for the release of soluble chemical oxygen demand (SCOD) of unit sludge and decrease of sludge concentration were as follows: 36.55 g x L(-1), pH 12.45, 175 degrees C and 60 min. While the optimal conditions for the decrease of particle size and fractal dimension were 36.55 g x L(-1), pH 12.5, 175 degrees C and 45 min.

  3. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2004-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  4. High temperature decomposition of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  5. Evolution of alkaline phosphatases in primates.

    PubMed Central

    Goldstein, D J; Rogers, C; Harris, H

    1982-01-01

    Alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] in placenta, intestine, liver, kidney, bone, and lung from a variety of primate species has been characterized by quantitative inhibition, thermostability, and immunological studies. Characteristic human placental-type alkaline phosphatase occurs in placentas of great apes (chimpanzee and orangutan) but not in placentas of other primates, including gibbon. It is also present in trace amounts in human lung but not in lung or other tissues of various Old and New World monkeys. However, a distinctive alkaline phosphatase resembling it occurs in substantial amounts in lungs from Old World monkeys but not New World monkeys. It appears that duplication of alkaline phosphatase genes and mutations of genetic elements controlling their tissue expression have occurred relatively recently in mammalian evolution. Images PMID:6950431

  6. Alkaline pH sensor molecules.

    PubMed

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range.

  7. [Hydrogen peroxide in the troposphere].

    PubMed

    Pehnec, Gordana

    2007-06-01

    The past few decades saw a rising interest in the role of hydrogen peroxide (H2O2) in atmospheric chemistry and its contribution to the formation of free radicals. Free radicals (oxidants) are formed by photochemical reactions between ozone and H2O2. Free radicals formed within cells can oxidise biomolecules, and this may lead to cell death and tissue injury. For this reason, free radicals are believed to cause more than 100 diseases. H2O2 has been suggested as a better indicator of atmospheric oxidation capacity than ozone. Atmospheric H2O2 can appear in the gas phase or in the aqueous phase. It shows typical diurnal and seasonal variations. However, measurements of H2O2 with expensive and sophisticated equipment are rare and limited to but a few sites in the world. Measurements in Greenland ice cores showed that H2O2 concentrations increased over the last 200 years and most of the increase has occurred over the last 20 years. Evaluations show that concentrations will still rise as a result of decreasing SO2 emission. H2O2 measurements have not been carried out in Croatia until now, and, accompanied by the existing longterm measurements of ozone and nitrogen oxides, they will provide an idea of the oxidative capacity of the atmosphere and its influence on oxidative stress.

  8. Microwave pretreatment for enhancement of phosphorus release from dairy manure.

    PubMed

    Pan, Szu-Hua; Lo, Kwang Victor; Liao, Ping Huang; Schreier, Hans

    2006-01-01

    Both the advanced oxidation process (AOP) using a combination of hydrogen peroxide addition and microwave heating (H2O2/microwave), and the microwave heating process were used for solubilization of phosphorus from liquid dairy manure. About 80% of total phosphate was released into the solution at a microwave heating time of 5 min at 170 degrees C. With an addition of H2O2, more than 81% of total phosphate could be released over a reaction period of 49 h at ambient temperature. The AOP process could achieve up to 85% of total phosphate release at 120 degrees C. The results indicated that both the microwave, and the AOP processes could effectively release phosphate from liquid dairy manure. These processes could serve as pretreatments for phosphorus recovery from animal wastes, and could be combined with the struvite crystallization process to provide a new approach in treating animal wastes.

  9. Photoproduction of catalase-insensitive peroxides on the donor side of manganese-depleted photosystem II: evidence with a specific fluorescent probe.

    PubMed

    Khorobrykh, Sergey A; Khorobrykh, Andrei A; Yanykin, Denis V; Ivanov, Boris N; Klimov, Vyacheslav V; Mano, Jun'ichi

    2011-12-13

    The photoproduction of organic peroxides (ROOH) in photosystem II (PSII) membranes was studied using the fluorescent probe Spy-HP. Two types of peroxide, highly lipophilic ones and relatively hydrophilic ones, were distinguished by the rate of reaction with Spy-HP; the former oxidized Spy-HP to the higher fluorescent form Spy-HPOx within 5 min, while the latter did so very slowly (the reaction was still not completed after 180 min). The level of photoproduction of these peroxides was significantly larger in the alkaline-treated, Mn-depleted PSII membranes than that in the untreated membranes, and it was suppressed by an artificial electron donor (diphenylcarbazide or ferrocyanide) and by the electron transport inhibitor diuron. Postillumination addition of Fe(2+) ions, which degrade peroxides by the Fenton mechanism, abolished the accumulation of Spy-HPOx, but catalase did not change the peroxide level, indicating that the detected species were organic peroxides, excluding H(2)O(2). These results agreed with our previous observation of an electron transport-dependent O(2) consumption on the PSII donor side and indicated that ROOH accumulated via a radical chain reaction that started with the formation of organic radicals on the donor side. Illumination (λ > 600 nm; 1500 μmol of photons m(-2) s(-1)) of the Mn-depleted PSII membranes for 3 min resulted in the formation of nearly 200 molecules of hydrophilic ROOH per reaction center, but only four molecules of highly lipophilic ROOH. The limited formation of the latter was due to the limited supply of its precursor to the reaction, suggesting that it represented structurally fixed peroxides, i.e., either protein peroxides or peroxides of the lipids tightly bound to the core complex. These ROOH forms, likely including several species derived from lipid peroxides, may mediate the donor side-induced photoinhibition of PSII via protein modification.

  10. Isothermal Decomposition of Hydrogen Peroxide Dihydrate

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Baragiola, R. A.

    2011-01-01

    We present a new method of growing pure solid hydrogen peroxide in an ultra high vacuum environment and apply it to determine thermal stability of the dihydrate compound that forms when water and hydrogen peroxide are mixed at low temperatures. Using infrared spectroscopy and thermogravimetric analysis, we quantified the isothermal decomposition of the metastable dihydrate at 151.6 K. This decomposition occurs by fractional distillation through the preferential sublimation of water, which leads to the formation of pure hydrogen peroxide. The results imply that in an astronomical environment where condensed mixtures of H2O2 and H2O are shielded from radiolytic decomposition and warmed to temperatures where sublimation is significant, highly concentrated or even pure hydrogen peroxide may form.

  11. Ultrafast Photoinduced Electron Transfer from Peroxide Dianion.

    PubMed

    Anderson, Bryce L; Maher, Andrew G; Nava, Matthew; Lopez, Nazario; Cummins, Christopher C; Nocera, Daniel G

    2015-06-18

    The encapsulation of peroxide dianion by hexacarboxamide cryptand provides a platform for the study of electron transfer of isolated peroxide anion. Photoinitiated electron transfer (ET) between freely diffusing Ru(bpy)3(2+) and the peroxide dianion occurs with a rate constant of 2.0 × 10(10) M(-1) s(-1). A competing electron transfer quenching pathway is observed within an ion pair. Picosecond transient spectroscopy furnishes a rate constant of 1.1 × 10(10) s(-1) for this first-order process. A driving force dependence for the ET rate within the ion pair using a series of Ru(bpy)3(2+) derivatives allows for the electronic coupling and reorganization energies to be assessed. The ET reaction is nonadiabatic and dominated by a large inner-sphere reorganization energy, in accordance with that expected for the change in bond distance accompanying the conversion of peroxide dianion to superoxide anion.

  12. NASA Hydrogen Peroxide Propellant Hazards Technical Manual

    NASA Technical Reports Server (NTRS)

    Baker, David L.; Greene, Ben; Frazier, Wayne

    2005-01-01

    The Fire, Explosion, Compatibility and Safety Hazards of Hydrogen Peroxide NASA technical manual was developed at the NASA Johnson Space Center White Sands Test Facility. NASA Technical Memorandum TM-2004-213151 covers topics concerning high concentration hydrogen peroxide including fire and explosion hazards, material and fluid reactivity, materials selection information, personnel and environmental hazards, physical and chemical properties, analytical spectroscopy, specifications, analytical methods, and material compatibility data. A summary of hydrogen peroxide-related accidents, incidents, dose calls, mishaps and lessons learned is included. The manual draws from art extensive literature base and includes recent applicable regulatory compliance documentation. The manual may be obtained by United States government agencies from NASA Johnson Space Center and used as a reference source for hazards and safe handling of hydrogen peroxide.

  13. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  14. Semicarbazide-sensitive amine oxidase substrates potentiate hydralazine hypotension: possible role of hydrogen peroxide.

    PubMed

    Vidrio, Horacio; Medina, Martha; González-Romo, Pilar; Lorenzana-Jiménez, Marte; Díaz-Arista, Patricia; Baeza, Alejandro

    2003-11-01

    The relation between inhibition of semicarbazide-sensitive amine oxidase (SSAO) and vasodilation by hydralazine (HYD) was evaluated in chloralose/urethane-anesthetized rats pretreated with various substrates of the enzyme and subsequently administered a threshold hypotensive dose of the vasodilator. The SSAO substrates benzylamine, phenethylamine, and methylamine potentiate the hypotensive response to HYD. Methylamine, which was studied in greater detail because of its status as a possible endogenous SSAO substrate, does not influence the response to the reference vasodilator pinacidil; it does enhance HYD relaxation in aortic rings obtained from pretreated rats. Experiments designed to identify the product of SSAO activity responsible for potentiation by methylamine suggest involvement of hydrogen peroxide (H2O2), as evidenced by the findings that such potentiation is abolished by additional pretreatment with the H2O2-metabolizing enzyme catalase, and that the plasma concentration of H2O2 is increased by methylamine and decreased by HYD. These results are interpreted as a substantiation of the relation between the known SSAO inhibitory effect of HYD and its vasodilator activity. Pretreatment with the SSAO substrates would increase production of H2O2 in vascular smooth muscle and thus magnify the influence of this vasoconstrictor agent on vascular tone. In these conditions, the decrease in H2O2 production and hence in vascular tone caused by SSAO inhibition by HYD would also be magnified. It is speculated that inhibition of vascular SSAO could represent a novel mechanism of vasodilation.

  15. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell.

    PubMed

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D

    2012-11-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells.

  16. Hydrogen Peroxide as a Sustainable Energy Carrier: Electrocatalytic Production of Hydrogen Peroxide and the Fuel Cell

    PubMed Central

    Fukuzumi, Shunichi; Yamada, Yusuke; Karlin, Kenneth D.

    2012-01-01

    This review describes homogeneous and heterogeneous catalytic reduction of dioxygen with metal complexes focusing on the catalytic two-electron reduction of dioxygen to produce hydrogen peroxide. Whether two-electron reduction of dioxygen to produce hydrogen peroxide or four-electron O2-reduction to produce water occurs depends on the types of metals and ligands that are utilized. Those factors controlling the two processes are discussed in terms of metal-oxygen intermediates involved in the catalysis. Metal complexes acting as catalysts for selective two-electron reduction of oxygen can be utilized as metal complex-modified electrodes in the electrocatalytic reduction to produce hydrogen peroxide. Hydrogen peroxide thus produced can be used as a fuel in a hydrogen peroxide fuel cell. A hydrogen peroxide fuel cell can be operated with a one-compartment structure without a membrane, which is certainly more promising for the development of low-cost fuel cells as compared with two compartment hydrogen fuel cells that require membranes. Hydrogen peroxide is regarded as an environmentally benign energy carrier because it can be produced by the electrocatalytic two-electron reduction of O2, which is abundant in air, using solar cells; the hydrogen peroxide thus produced could then be readily stored and then used as needed to generate electricity through the use of hydrogen peroxide fuel cells. PMID:23457415

  17. Chemiluminescence of Organic Peroxides. Thermal Generation of an o-Xylylene Peroxide.

    DTIC Science & Technology

    1981-04-07

    AD-A098 078 ILLINOIS LIIIV AT URBANA DEPT OF CHEMISTRY F/G 7/4 CHEMILLUMINESCENSE OF ORGANIC PEROXIDES - THERMAL GENERATION OF A--ETC (U) APR 81 J P...11’r- 4. 1 L E (ad Subtitle) or REPORT or R1 0 CRED emilum’i-nescence of Organic Peroxides . Thrai ehia Generation of an o-Xylylene Peroxide ,,, erm...Iq It. KEY WORDS (Countinue oni tow.e*ole At neesar did tffoiltl by *lack Mmber) ?T. chemil uminesceflce AR~~ 1 * peroxides A CIEEL therniol1ys is b

  18. Environmentally Friendly Zirconium Oxide Pretreatment

    DTIC Science & Technology

    2013-05-01

    functional carboxylic acid additives 52 Figure 37 Salt Spray Corrosion Resistance of zirconium Dried- In-Place treatment made from alternate sources...GMW14872 (40 cycles) Corrosion Performance of DIP formulations with metal salts and modified organic acids versus commercial controls on aluminum... corrosion , dried-in-place, depot, environment, hexafluorozirconic acid , hexavalent chromium, paint, pretreatment, primer, steel, TT-C-490E

  19. EFFLUENT TREATMENT FACILITY PEROXIDE DESTRUCTION CATALYST TESTING

    SciTech Connect

    HALGREN DL

    2008-07-30

    The 200 Area Effluent Treatment Facility (ETF) main treatment train includes the peroxide destruction module (PDM) where the hydrogen peroxide residual from the upstream ultraviolet light/hydrogen peroxide oxidation unit is destroyed. Removal of the residual peroxide is necessary to protect downstream membranes from the strong oxidizer. The main component of the PDM is two reaction vessels utilizing granular activated carbon (GAC) as the reaction media. The PDM experienced a number of operability problems, including frequent plugging, and has not been utilized since the ETF changed to groundwater as the predominant feed. The unit seemed to be underperforming in regards to peroxide removal during the early periods of operation as well. It is anticipated that a functional PDM will be required for wastewater from the vitrification plant and other future streams. An alternate media or methodology needs to be identified to replace the GAC in the PDMs. This series of bench scale tests is to develop information to support an engineering study on the options for replacement of the existing GAC method for peroxide destruction at the ETF. A number of different catalysts will be compared as well as other potential methods such as strong reducing agents. The testing should lead to general conclusions on the viability of different catalysts and identify candidates for further study and evaluation.

  20. 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

  1. Process for extracting technetium from alkaline solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

    1995-01-01

    A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

  2. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  3. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  4. Biological treatment of a high strength wastewater enhanced by chemical pretreatment

    SciTech Connect

    Menon, P.; Hung, Y.T.

    1995-12-31

    Biological treatment has been established to be one of the most economic means for the treatment of industrial wastewater. However inhibition of the biomass while treating wastewater containing significant concentration of toxics and heavy metals has been the deterrent for the application of this method. Reducing the toxicity by pretreatment could render the wastewater more amenable to biodegradation. In this research project, biodegradation of a high strength oily wastewater containing solvents and heavy metals was studied employing 9 activated sludge reactor experiments. Initial TOC of the wastewater was determined to be 8,500 mg/L. Enhancement of the biodegradation process by pretreating the wastewater was also studied. Pretreatment techniques employed were: (A) Coagulation using a 400 ppm solution of Ferric Chloride and (B) coagulation followed by chemical oxidation using hydrogen peroxide catalyzed by ferrous ions. A period of 24 hours was allowed as settling time during coagulation and as reaction time during chemical oxidation. 10 reactors containing varying concentrations of the wastewater were seeded with different dosages of Liquid Live Microorganisms (LLMO). Reaction time allowed for the biodegradation experiments was 48 hours. TOC removal by pretreatment alone was approximately 12% after coagulation and approximately 20% after coagulation and oxidation. Results are presented for the varying experimental conditions studied. TOC removal by biodegradation was observed to be significantly enhanced by pretreatment.

  5. Steam pretreatment of Saccharum officinarum L. bagasse by adding of impregnating agents for advanced bioethanol production.

    PubMed

    Verardi, A; Blasi, A; De Bari, I; Calabrò, V

    2016-12-01

    The main byproduct of the sugarcane industry, Saccharum officinarum L. bagasse (sugarcane bagasse, SCB), is widely used as lignocellulose biomass for bio-ethanol (EtOH) production. In this research study, SCB was pretreated by steam explosion (SE) method using two different impregnating agents: sulfur dioxide (SD) and hydrogen peroxide (HP). As matter of fact, the use of impregnating agents improves the performance of SE method, increasing the concentrations of fermentable sugars after enzymatic saccharification, and decreasing the inhibitor compounds produced during the steam pretreatment step. The aim of this study was to investigate and compare the use of the two impregnating agents in various SE-conditions in order to optimize pretreatment parameters. For every pretreatment condition, it has been evaluated: concentration of fermentable sugars, glucose and xylose yields, and the effects of the inhibitor compounds on enzymatic hydrolysis step. The obtained results allow to improve the efficiency of the whole process of bio-EtOH synthesis enhancing the amount of fermentable sugars produced and the eco-sustainability of the whole process. Indeed, the optimization of steam pretreatment leads to a reduction of energy requirements and to a lower environmental impact.

  6. Improving enzymatic saccharification of bamboo shoot shell by alkalic salt pretreatment with H2O2.

    PubMed

    Qing, Qing; Zhou, Linlin; Huang, Meizi; Guo, Qi; He, Yucai; Wang, Liqun; Zhang, Yue

    2016-02-01

    Pretreatment of bamboo shoot shell (BSS) by a combination of alkalic salts with hydrogen peroxide (H2O2) was evaluated for its delignification effect and for its ability to enhance enzymatic saccharification of pretreated solids. By comparing different alkalic salts, the combination of 9% Na3PO4·12H2O and 0.3g/g H2O2 (ASHP) was identified as an effective system that showed the highest delignification of 87.7% and the total reducing sugar yield of 97.1% when pretreated BSS at a solid to liquid ratio of 1/20 (w/w) at 80°C for 2h. The delignification effect and the disruption of the lignocelluloses structure by this novel pretreatment method were deduced to be the main reasons that led to enhanced enzymatic saccharification as supported by the chemical composition analysis and the results of SEM, FTIR and XRD analyses of the untreated and alkalic salt pretreated BSS.

  7. PROCESS OF ELIMINATING HYDROGEN PEROXIDE IN SOLUTIONS CONTAINING PLUTONIUM VALUES

    DOEpatents

    Barrick, J.G.; Fries, B.A.

    1960-09-27

    A procedure is given for peroxide precipitation processes for separating and recovering plutonium values contained in an aqueous solution. When plutonium peroxide is precipitated from an aqueous solution, the supernatant contains appreciable quantities of plutonium and peroxide. It is desirable to process this solution further to recover plutonium contained therein, but the presence of the peroxide introduces difficulties; residual hydrogen peroxide contained in the supernatant solution is eliminated by adding a nitrite or a sulfite to this solution.

  8. Exogenous low-dose hydrogen peroxide enhances drought tolerance of soybean (Glycine max L.) through inducing antioxidant system.

    PubMed

    Guler, Neslihan Saruhan; Pehlivan, Necla

    2016-06-01

    Hydrogen peroxide (H(2)O(2)) functions as a signal molecule in plants under abiotic and biotic stress. In this study, the role of exogenous H(2)O(2) in improving drought tolerance in two soybean cultivars (Glycine max L. Merrill) differing in their tolerance to drought was evaluated. Plants were grown in plastic pots with normal irrigation in a phytotron. Four weeks after radicle emergence, either 1 mM H(2)O(2) or distilled water was sprayed as foliar onto the leaves of each plant, after drought stress was applied. Leaf samples were harvested on the 4(th) and 7(th) days of the drought. Antioxidant-related enzyme activity, such as the superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), hydrogen peroxide (H(2)O(2)) and malondialdehyde (MDA) content was measured during the drought period. Drought stress decreased leaf water potential, relative water content and photosynthetic pigment content but enhanced lipid peroxidation and endogenous H(2)O(2) concentration. By contrast, exogenous low dose H(2)O(2) improved water status, pigment content and lipid peroxidation under drought stress. Endogenous H(2)O(2) concentration was reduced by exogenous H(2)O(2) as compared to drought treatment alone. H(2)O(2) pre-treatment induced all the antioxidant enzyme activities, to a greater extent than the control leaves, during drought. H(2)O(2) pretreatment further enhanced the activities of antioxidant enzymes in the tolerant cultivar compared to the sensitive cultivar. Results suggested that low dose H(2)O(2) pre-treatment alleviated water loss and H(2)O(2) content and increased drought stress tolerance by inducing the antioxidant system.

  9. Effect of exogenous spermidine on polyamine content and metabolism in tomato exposed to salinity-alkalinity mixed stress.

    PubMed

    Hu, Xiaohui; Zhang, Yi; Shi, Yu; Zhang, Zhi; Zou, Zhirong; Zhang, Hao; Zhao, Jiuzhou

    2012-08-01

    We investigated the effects of seeds pretreatment with exogenous spermidine (Spd) on the polyamine content and metabolism in the roots of two cultivars of tomato (Solanum lycopersicum), Jinpengchaoguan and Zhongza No. 9 grown under conditions of mixed salinity-alkalinity stress. These cultivars differ in their tolerance to salinity stress, with the former more tolerant than the latter. PA content, whether in its free forms, soluble conjugated forms, or insoluble bound forms, increased significantly during salinity-alkalinity stress. The activities of S-adenosylmethionine decarboxylase (SAMDC) and diamine oxidase (DAO), concentrations of free Spd, soluble conjugated forms of Spd and spermine (Spm), and insoluble bound form of Spd in the roots were enhanced to a greater extent in cv. Jinpengchaoguan roots than in cv. Zhongza No.9 in response to salinity-alkalinity stress. Interestingly, Spd application to seeds markedly suppressed the accumulation of free Put, but promoted an increase in free Spd and Spm concentrations, as well as soluble conjugated forms of Spd and insoluble bound forms of Put in both cultivars. From these data, we deduced that exogenous Spd promotes the conversion of free Put into free Spd and Spm, and soluble conjugated forms and insoluble bound forms of PAs under salinity-alkalinity stress. Furthermore, under salinity-alkalinity stress conditions, exogenous Spd enhanced the activities of ODC, SAMDC and DAO, and reduced the activities of ADC and polyamine oxidase (PAO) in cv. Zhongza No.9 roots. In addition, exogenous Spd reduced the activities of ADC and ODC, and increased the activities of DAO and SAMDC in cv. Jinpengchaoguan roots under salinity-alkalinity stress conditions. These results suggest that exogenous Spd treatment can regulate the metabolic status of polyamines caused by salinity-alkalinity stress, and eventually enhance tolerance of tomato plants to salinity-alkalinity stress. Additionally, Spd treatments have varying effects on

  10. Catalyst Development for Hydrogen Peroxide Rocket Engines

    NASA Technical Reports Server (NTRS)

    Morlan, P. W.; Wu, P.-K.; Ruttle, D. W.; Fuller, R. P.; Nejad, A. S.; Anderson, W. E.

    1999-01-01

    The development of various catalysts of hydrogen peroxide was conducted for the applications of liquid rocket engines. The catalyst development includes silver screen technology, solid catalyst technology, and homogeneous catalyst technology. The silver screen technology development was performed with 85% (by weight) hydrogen peroxide. The results of this investigation were used as the basis for the catalyst design of a pressure-fed liquid-fueled upper stage engine. Both silver-plated nickel 200 screens and pure silver screens were used as the active metal catalyst during the investigation, The data indicate that a high decomposition efficiency (greater than 90%) of 85% hydrogen peroxide can be achieved at a bed loading of 0.5 lbm/sq in/sec with both pure silver and silver plated screens. Samarium oxide coating, however, was found to retard the decomposition process and the catalyst bed was flooded at lower bed loading. A throughput of 200 lbm of hydrogen peroxide (1000 second run time) was tested to evaluate the catalyst aging issue and performance degradation was observed starting at approximately 400 seconds. Catalyst beds of 3.5 inch in diameter was fabricated using the same configuration for a 1,000-lbf rocket engine. High decomposition efficiency was obtained with a low pressure drop across the bed. Solid catalyst using precious metal was also developed for the decomposition of hydrogen peroxide from 85% to 98% by weight. Preliminary results show that the catalyst has a strong reactivity even after 15 minutes of peroxide decomposition. The development effort also includes the homogeneous catalyst technology. Various non-toxic catalysts were evaluated with 98% peroxide and hydrocarbon fuels. The results of open cup drop tests indicate an ignition delay around 11 ms.

  11. 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.

  12. 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

  13. Alkaline tolerant dextranase from streptomyces anulatus

    DOEpatents

    Decker, Stephen R.; Adney, William S.; Vinzant, Todd B.; Himmel, Michael E.

    2003-01-01

    A process for production of an alkaline tolerant dextranase enzyme comprises culturing a dextran-producing microorganism Streptomyces anulatus having accession no. ATCC PTA-3866 to produce an alkaline tolerant dextranase, Dex 1 wherein the protein in said enzyme is characterized by a MW of 63.3 kDa and Dex 2 wherein its protein is characterized by a MW of 81.8 kDa.

  14. Technetium recovery from high alkaline solution

    DOEpatents

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  15. Toxicity of alkalinity to Hyalella azteca

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.

    1997-01-01

    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  16. Safe handling of potential peroxide forming compounds and their corresponding peroxide yielded derivatives.

    SciTech Connect

    Sears, Jeremiah Matthew; Boyle, Timothy J.; Dean, Christopher J.

    2013-06-01

    This report addresses recent developments concerning the identification and handling of potential peroxide forming (PPF) and peroxide yielded derivative (PYD) chemicals. PPF chemicals are described in terms of labeling, shelf lives, and safe handling requirements as required at SNL. The general peroxide chemistry concerning formation, prevention, and identification is cursorily presented to give some perspective to the generation of peroxides. The procedure for determining peroxide concentrations and the proper disposal methods established by the Hazardous Waste Handling Facility are also provided. Techniques such as neutralization and dilution are provided for the safe handling of any PYD chemicals to allow for safe handling. The appendices are a collection of all available SNL documentation pertaining to PPF/PYD chemicals to serve as a single reference.

  17. Alkaline Water and Longevity: A Murine Study

    PubMed Central

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  18. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  19. Salidroside inhibits endogenous hydrogen peroxide induced cytotoxicity of endothelial cells.

    PubMed

    Zhao, Xingyu; Jin, Lianhai; Shen, Nan; Xu, Bin; Zhang, Wei; Zhu, Hongli; Luo, Zhengli

    2013-01-01

    Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3-4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.

  20. Phytic acid inhibits lipid peroxidation in vitro.

    PubMed

    Zajdel, Alicja; Wilczok, Adam; Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10-20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

  1. Phytic Acid Inhibits Lipid Peroxidation In Vitro

    PubMed Central

    Węglarz, Ludmiła; Dzierżewicz, Zofia

    2013-01-01

    Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100 μM and 500 μM effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100 μM and 500 μM significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100 μM and 500 μM) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products. PMID:24260736

  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. 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.

  4. 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.

  5. In vivo imaging of hydrogen peroxide with chemiluminescent nanoparticles.

    PubMed

    Lee, Dongwon; Khaja, Sirajud; Velasquez-Castano, Juan C; Dasari, Madhuri; Sun, Carrie; Petros, John; Taylor, W Robert; Murthy, Niren

    2007-10-01

    The overproduction of hydrogen peroxide is implicated in the development of numerous diseases and there is currently great interest in developing contrast agents that can image hydrogen peroxide in vivo. In this report, we demonstrate that nanoparticles formulated from peroxalate esters and fluorescent dyes can image hydrogen peroxide in vivo with high specificity and sensitivity. The peroxalate nanoparticles image hydrogen peroxide by undergoing a three-component chemiluminescent reaction between hydrogen peroxide, peroxalate esters and fluorescent dyes. The peroxalate nanoparticles have several attractive properties for in vivo imaging, such as tunable wavelength emission (460-630 nm), nanomolar sensitivity for hydrogen peroxide and excellent specificity for hydrogen peroxide over other reactive oxygen species. The peroxalate nanoparticles were capable of imaging hydrogen peroxide in the peritoneal cavity of mice during a lipopolysaccharide-induced inflammatory response. We anticipate numerous applications of peroxalate nanoparticles for in vivo imaging of hydrogen peroxide, given their high specificity and sensitivity and deep-tissue-imaging capability.

  6. Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids.

    PubMed

    Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

    2016-01-01

    In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

  7. [Alkaline phosphatase in Amoeba proteus].

    PubMed

    Sopina, V A

    2005-01-01

    In free-living Amoeba proteus (strain B), 3 phosphatase were found after disc-electrophoresis of 10 microg of protein in PAGE and using 1-naphthyl phosphate as a substrate a pH 9.0. These phosphatases differed in their electrophoretic mobilities - "slow" (1-3 bands), "middle" (one band) and "fast" (one band). In addition to 1-naphthyl phosphate, "slow" phosphatases were able to hydrolyse 2-naphthyl phosphate and p-nitrophenyl phosphate. They were slightly activated by Mg2+, completely inhibited by 3 chelators (EDTA, EGTA and 1,10-phenanthroline), L-cysteine, sodium dodecyl sulfate and Fe2+, Zn2+ and Mn2+ (50 mM), considerably inactivated by orthovanadate, molybdate, phosphatase inhibitor cocktail 1, p-nitrophenyl phosphate, Na2HPO4, DL-dithiothreitol and urea and partly inhibited by H2O2, DL-phenylalanine, 2-mercaptoethanol, phosphatase inhibitor cocktail 2 and Ca2+. Imidazole, L-(+)-tartrate, okadaic acid, NaF and sulfhydryl reagents -p-(hydroxy-mercuri)benzoate and N-ethylmaleimide - had no influence on the activity of "slow" phosphatases. "Middle" and "fast" phosphatases, in contrast to "slow" ones, were not inactivated by 3 chelators. The "middle" phosphatase differed from the "fast" one by smaller resistance to urea, Ca2+, Mn2+, phosphates and H2O2 and greater resistance to dithiothreitol and L-(+)-tartrate. In addition, the "fast" phosphatase was inhibited by L-cysteine but the "middle" one was activated by it. Of 5 tested ions (Mg2+, Cu2+, Mn2+, Ca2+ and Zn2+), only Zn2+ reactivated "slow" phosphatases after their inactivation by EDTA treatment. The reactivation of apoenzyme was only partial (about 35 %). Thus, among phosphatases found in amoebae at pH 9.0, only "slow" ones are Zn-metalloenzymes and may be considered as alkaline phosphatases (EC 3.1.3.1). It still remains uncertain, to which particular phosphatase class "middle" and "fast" phosphatases (pH 9.0) may belong.

  8. Bacillus licheniformis proteases as high value added products from fermentation of wastewater sludge: pre-treatment of sludge to increase the performance of the process.

    PubMed

    Drouin, M; Lai, C K; Tyagi, R D; Surampalli, R Y

    2008-01-01

    Wastewater sludge is a complex raw material that can support growth and protease production by Bacillus licheniformis. In this study, sludge was treated by different thermo-alkaline pre-treatment methods and subjected to Bacillus licheniformis fermentation in bench scale fermentors under controlled conditions. Thermo-alkaline treatment was found to be an effective pre-treatment process in order to enhance the proteolytic activity. Among the different pre-treated sludges tested, a mixture of raw and hydrolysed sludge caused an increase of 15% in the protease activity, as compared to the untreated sludge. The benefit of hydrolysis has been attributed to a better oxygen transfer due to decrease in media viscosity and to an increase in nutrient availability. Foam formation was a major concern during fermentation with hydrolysed sludge. The studies showed that addition of a chemical anti-foaming agent (polypropylene glycol) during fermentation to control foam could negatively influence the protease production by increasing the viscosity of sludge.

  9. Lipid Peroxidation and Its Toxicological Implications

    PubMed Central

    Nam, Tae-gyu

    2011-01-01

    Lipid peroxidation is a free radical oxidation of polyunsaturated fatty acids such as linoleic acid or arachidonic acid. This process has been related with various pathologies and disease status mainly because of the oxidation products formed during the process. The oxidation products include reactive aldehydes such as malondialdehyde and 4-hydroxynonenal. These reactive aldehydes can form adducts with DNAs and proteins, leading to the alterations in their functions to cause various diseases. This review will provide a short summary on the implication of lipid peroxidation on cancer, atherosclerosis, and neurodegeneration as well as chemical and biochemical mechanisms by which these adducts affect the pathological conditions. In addition, select examples will be presented where antioxidants were used to counteract oxidative damage caused by lipid peroxidation. At the end, isoprostanes are discussed as a gold standard for the assessment of oxidative damages. PMID:24278542

  10. Hydrogen Peroxide - Material Compatibility Studied by Microcalorimetry

    NASA Technical Reports Server (NTRS)

    Homung, Steven D.; Davis, Dennis D.; Baker, David; Popp, Christopher G.

    2003-01-01

    Environmental and toxicity concerns with current hypergolic propellants have led to a renewed interest in propellant grade hydrogen peroxide (HP) for propellant applications. Storability and stability has always been an issue with HP. Contamination or contact of HP with metallic surfaces may cause decomposition, which can result in the evolution of heat and gas leading to increased pressure or thermal hazards. The NASA Johnson Space Center White Sands Test Facility has developed a technique to monitor the decompositions of hydrogen peroxide at temperatures ranging from 25 to 60 C. Using isothermal microcalorimetry we have measured decomposition rates at the picomole/s/g level showing the catalytic effects of materials of construction. In this paper we will present the results of testing with Class 1 and 2 materials in 90 percent hydrogen peroxide.

  11. Lipid peroxidation and its toxicological implications.

    PubMed

    Nam, Tae-Gyu

    2011-03-01

    Lipid peroxidation is a free radical oxidation of polyunsaturated fatty acids such as linoleic acid or arachidonic acid. This process has been related with various pathologies and disease status mainly because of the oxidation products formed during the process. The oxidation products include reactive aldehydes such as malondialdehyde and 4-hydroxynonenal. These reactive aldehydes can form adducts with DNAs and proteins, leading to the alterations in their functions to cause various diseases. This review will provide a short summary on the implication of lipid peroxidation on cancer, atherosclerosis, and neurodegeneration as well as chemical and biochemical mechanisms by which these adducts affect the pathological conditions. In addition, select examples will be presented where antioxidants were used to counteract oxidative damage caused by lipid peroxidation. At the end, isoprostanes are discussed as a gold standard for the assessment of oxidative damages.

  12. Comparison of different alkali-based pretreatments of corn stover for improving enzymatic saccharification.

    PubMed

    Li, Qiang; Gao, Yang; Wang, Haisong; Li, Bin; Liu, Chao; Yu, Guang; Mu, Xindong

    2012-12-01

    Corn stover was treated with NaOH, NaOH+anthraquinone (AQ), NaOH+Na(2)SO(3) (alkaline), NaOH+Na(2)SO(3) (neutral), and NaOH+Na(2)S, respectively. The treated corn stover was subjected to hydrolysis with cellulase (20 FPU/g dry biomass) and β-glucosidase (10I U/g dry biomass). Compared with other pretreatment methods, alkaline sodium sulfite pretreatment (ASSP) at a relatively low temperature of 140°C provided for the best lignin removal of about 92%. After ASSP with 10 wt.% of the total alkali charge (Na(2)SO(3):NaOH=1:1) at 140°C for 30 min and subsequent enzymatic hydrolysis, a total sugar yield of 78.2% was obtained on the basis of the amount of glucose and xylose released from raw corn stover. This yield was 24.0% higher than that achieved with NaOH only under the same conditions. Therefore, the supplement of Na(2)SO(3) in alkali pretreatment can facilitate delignification and significantly improve the enzymatic saccharification.

  13. [Enhancement for anaerobic digestion of sewage sludge pretreated by microwave and its combined processes ].

    PubMed

    Liu, Ji-bao; Ni, Xiao-tang; Wei, Yuan-song; Tong, Juan; Wang, Ya-wei

    2014-09-01

    To improve anaerobic digestion and dewatering of sludge, impacts of sludge pretreated by microwave (MW) and its combined processes on sludge anaerobic digestion and dewatering were investigated. The results showed that microwave and its combined processes could effectively enhance anaerobic sludge digestion. Not only the cumulative methane production in the test of the MW-H2O2-alkaline (0. 2) was increased by 13. 34% compared with the control, but also its methane production rate was much higher than that of the control. Compared with the single MW process, the addition of both H2O2 and alkaline enhanced the solubilization of particle COD( >0. 45 micron) , indicating that synergistically generated soluble organics were faster to biodegrade which resulted in the enhancement of anaerobic digestion. The MW-acid process was effective in improving sludge dewaterability, e. g. , Capillary Suction Time (CST) at only 9. 85 s. The improvement of sludge dewatering was significantly correlated with sludge physical properties such as zeta potential, surface charge density and particle size. Under different sludge pretreatment conditions, the sludge dewatering after anaerobic digestion was similar, though the difference of sludge dewatering to some degrees was observed for pretreated sludge.

  14. [Analysis of hydrolytic enzyme activities on sludge aerobic/anoxic digestion after ultrasonic pretreatment].

    PubMed

    Ye, Yun-di; Sun, Shui-yu; Zheng, Li; Liu, Bao-jian; Xu, Yan-bin; Zhan, Xing-xing; Liu, Jing-yong

    2012-08-01

    In order to evaluate the function of sludge aerobic/anoxic digestibility by ultrasonic pretreatment. The SS, VSS and hydrolytic enzyme activities (amylase, glucosidase, protease, phosphatase) were measured before and after ultrasonic pretreatment (28 kHz, 0.15 kW x L(-1), 10 min). The results showed that the performances of aerobic/anoxic were greatly improved after ultrasonic pretreatment, the removal efficiency of VSS went to 44.3%, 7.8% better than of traditional aerobic/anoxic digestion. The variational trend of sludge hydrolytic enzyme activities increased firstly and then fell off during 13d digestion, the maximum of amylase activity and glucosidase activity in ultrasonic sludge, appeared in the 5 d, amylase activity was 0.104 micromol x g(-1) and glucosidase activity was 0.637 (micromol x g(-1). The maximum of intracellular protease activity and extracellular proteases activity in ultrasonic sludge, appeared in the 7 d, intracellular protease activity was 23.68 micromol x g(-1), higher than extracellular proteases activity, and it was playing a leading role in sludge digestion. The acid phosphatase activity of ultrasonic sludge was higher than the control sludge, and the alkaline phosphatase was sensitive to environment. So the alkaline phosphatase activity reduced when the internal properties of sludge was changed.

  15. Combined effects of Fenton peroxidation and CaO conditioning on sewage sludge thermal drying.

    PubMed

    Liu, Huan; Liu, Peng; Hu, Hongyun; Zhang, Qiang; Wu, Zhenyu; Yang, Jiakuan; Yao, Hong

    2014-12-01

    Joint application of Fenton's reagent and CaO can dramatically enhance sludge dewaterability, thus are also likely to affect subsequent thermal drying process. This study investigated the synergistic effects of the two conditioners on the thermal drying behavior of sewage sludge and the emission characteristics of main sulfur-/nitrogen-containing gases. According to the results, Fenton peroxidation combined with CaO conditioning efficiently promoted sludge heat transfer, reduced the amounts of both free and bound water, and created porous structure in solids to provide evaporation channels, thus producing significant positive effects on sludge drying performance. In this case, the required time for drying was shortened to one-third. Additionally, joint usage of Fenton's reagent and CaO did not increase the losses of organic matter during sludge drying process. Meanwhile, they facilitated the formation of sulfate and sulfonic acid/sulfone, leading to sulfur retention in dried sludge. Both of Fenton peroxidation and CaO conditioning promoted the oxidation, decomposition, and/or dissolution of protein and inorganic nitrogen in sludge pre-treatment. As a consequence, the emissions of sulfurous and nitrogenous gases from dewatered sludge drying were greatly suppressed. These indicate that combining Fenton peroxidation with CaO conditioning is a promising strategy to improve drying efficiency of sewage sludge and to control sulfur and nitrogen contaminants during sludge thermal drying process.

  16. Diazepam blocks striatal lipid peroxidation and improves stereotyped activity in a rat model of acute stress.

    PubMed

    Méndez-Cuesta, Luis A; Márquez-Valadez, Berenice; Pérez-De La Cruz, Verónica; Escobar-Briones, Carolina; Galván-Arzate, Sonia; Alvarez-Ruiz, Yarummy; Maldonado, Perla D; Santana, Ricardo A; Santamaría, Abel; Carrillo-Mora, Paul

    2011-11-01

    In this work, the effect of a single dose of diazepam was tested on different markers of oxidative damage in the striatum of rats in an acute model of immobilization (restraint) stress. In addition, the locomotor activity was measured at the end of the restraint period. Immobilization was induced to animals for 24 hr, and then, lipid peroxidation, superoxide dismutase activity and content, and mitochondrial function were all estimated in striatal tissue samples. Corticosterone levels were measured in serum. Diazepam was given to rats as a pre-treatment (1 mg/kg, i.p.) 20 min. before the initiation of stress. Our results indicate that acute stress produced enhanced striatal levels of lipid peroxidation (73% above the control), decreased superoxide dismutase activity (54% below the control), reduced levels of mitochondrial function (35% below the control) and increased corticosterone serum levels (86% above the control). Pre-treatment of stressed rats with diazepam decreased the striatal lipid peroxidation levels (68% below the stress group) and improved mitochondrial function (18% above the stress group), but only mild preservation of superoxide dismutase activity was detected (17% above the stress group). In regard to the motor assessment, only the stereotyped activity was increased in the stress group with respect to control (46% above the control), and this effect was prevented by diazepam administration (30% below the stress group). The preventive actions of diazepam in this acute model of stress suggest that drugs exhibiting anxiolytic and antioxidant properties might be useful for the design of therapies against early acute phases of physic stress.

  17. Peroxide as a Novel Treatment for Ecchymoses

    PubMed Central

    Sroa, Novie; Campbell, Shannon M.; Bechtel, Mark A.; Mitch Opremcak, E.

    2010-01-01

    Ecchymoses, commonly known as bruises, frequently occur after injury to the skin causes extravasation of red blood cells into interstitial tissue. This extravasation can lead to an inflammatory cascade. The case report presented details one patient who displayed rapid improvement in the pain and appearance of a partially treated bruise on her thigh after an eight-hour application of hydrogen peroxide 15% carbamide gel under occlusion. Hydrogen peroxide 15% carbamide gel may represent a novel treatment for ecchymoses. This potential new treatment for bruises needs to be studied further to detail its adverse effects, safety profile, and efficacy profile. PMID:21103315

  18. Prooxidative effect of copper--metallothionein in the acute cytotoxicity of hydrogen peroxide in Ehrlich ascites tumour cells.

    PubMed

    Suntres, Zacharias E; Lui, Edmund M K

    2006-01-16

    This study was concerned with the role of copper (Cu) and Cu-metallothionein (Cu-MT) in oxidative stress. Hydrogen peroxide (H(2)O(2))-induced oxidative injury was examined in Ehrlich ascites tumour cells isolated from host mice pretreated with 0, 1 or 2mg of CuSO(4) (ip) 24h earlier. Control Ehrlich cells contained low levels of Cu and Cu treatment produced dose-related increases in cellular Cu and Cu-MT levels and corresponding increases in sensitivity to oxidative toxicity of H(2)O(2) (LC(50), cell blebbing, lipid peroxidation, GSH depletion, and increase in intracellular free [Ca(2+)](i)). Hydrogen peroxide treatment also resulted in the oxidation of MT thiolates, reduction in the binding of Cu to MT resulting in translocation of Cu to other subcellular sites. d-penicillamine, a Cu-chelating agent, obliterated the sensitization effect of Cu-pretreatment and reduced the redistribution of MT-bound Cu, suggesting the participation of Cu ions derived from MT in promoting oxidant stress. Additional experiments with desferoxamine and mannitol have revealed the involvement of a Cu-dependent Fenton reaction in the mediation of the prooxidative effect of Cu-MT. These data suggest that cells with high levels of Cu-MT may be particularly susceptible to oxidative stress.

  19. Self-Assembly of Uranyl-Peroxide Nanocapsules in Basic Peroxidic Environments.

    PubMed

    Miró, Pere; Vlaisavljevich, Bess; Gil, Adria; Burns, Peter C; Nyman, May; Bo, Carles

    2016-06-13

    A wide range of uranyl-peroxide nanocapsules have been synthesized using very simple reactants in basic media; however, little is known about the process to form these species. We have performed a density functional theory study of the speciation of the uranyl ions under different experimental conditions and explored the formation of dimeric species via a ligand exchange mechanism. We shed some light onto the importance of the excess of peroxide and alkali counterions as a thermodynamic driving force towards the formation of larger uranyl-peroxide species.

  20. Heterogeneous catalytic degradation of cyanide using copper-impregnated pumice and hydrogen peroxide.

    PubMed

    Kitis, Mehmet; Karakaya, Emine; Yigit, Nevzat O; Civelekoglu, Gokhan; Akcil, Ata

    2005-04-01

    The main objective of this research was to investigate the oxidative destruction of free cyanide with hydrogen peroxide and copper-impregnated pumice as a heterogeneous catalyst. Original or copper-impregnated pumices added alone were not effective adsorbents of negatively charged cyanide ions due to incompatible surface interactions. Peroxide and original pumices added together were also ineffective in removing cyanide. However, for all of the three natural pumices tested with various particle size fractions, the use of copper-impregnated pumices and peroxide together significantly enhanced both the initial rate and extent of cyanide removal. Although copper-impregnated specific surface area was the major factor affecting the rate and extent of cyanide destruction for a particular pumice source with similar surface chemistries, the type of surface chemistry (i.e., specific functional groups) within different pumice sources also appears to be a very important factor. Lower rates and extents of cyanide removals were observed at pH 11 compared to pH 8 probably because of the negative impacts of alkaline conditions in terms of scavenging peroxide and forming more negatively charged pumice surfaces. Both the initial rate and ultimate extent of cyanide removals were generally higher at a temperature of 20 degrees C compared with those found at 10 degrees C. The use of copper-impregnated pumice as a light, cheap, readily available, natural, and porous heterogeneous catalyst either in completely mixed/suspended or fixed-bed reactor configurations may be an effective treatment technology for cyanide removal from solution. This new approach may minimize downstream metal removal problems experienced in conventional cyanide oxidation technologies.

  1. The effect of hydrogen peroxide on uranium oxide films on 316L stainless steel

    NASA Astrophysics Data System (ADS)

    Wilbraham, Richard J.; Boxall, Colin; Goddard, David T.; Taylor, Robin J.; Woodbury, Simon E.

    2015-09-01

    For the first time the effect of hydrogen peroxide on the dissolution of electrodeposited uranium oxide films on 316L stainless steel planchets (acting as simulant uranium-contaminated metal surfaces) has been studied. Analysis of the H2O2-mediated film dissolution processes via open circuit potentiometry, alpha counting and SEM/EDX imaging has shown that in near-neutral solutions of pH 6.1 and at [H2O2] ⩽ 100 μmol dm-3 the electrodeposited uranium oxide layer is freely dissolving, the associated rate of film dissolution being significantly increased over leaching of similar films in pH 6.1 peroxide-free water. At H2O2 concentrations between 1 mmol dm-3 and 0.1 mol dm-3, formation of an insoluble studtite product layer occurs at the surface of the uranium oxide film. In analogy to corrosion processes on common metal substrates such as steel, the studtite layer effectively passivates the underlying uranium oxide layer against subsequent dissolution. Finally, at [H2O2] > 0.1 mol dm-3 the uranium oxide film, again in analogy to common corrosion processes, behaves as if in a transpassive state and begins to dissolve. This transition from passive to transpassive behaviour in the effect of peroxide concentration on UO2 films has not hitherto been observed or explored, either in terms of corrosion processes or otherwise. Through consideration of thermodynamic solubility product and complex formation constant data, we attribute the transition to the formation of soluble uranyl-peroxide complexes under mildly alkaline, high [H2O2] conditions - a conclusion that has implications for the design of both acid minimal, metal ion oxidant-free decontamination strategies with low secondary waste arisings, and single step processes for spent nuclear fuel dissolution such as the Carbonate-based Oxidative Leaching (COL) process.

  2. The separation of platinum, palladium and gold from silicate rocks by the anion exchange separation of chloro complexes after a sodium peroxide fusion: an investigation of low recoveries.

    PubMed

    Enzweiler, J; Potts, P J

    1995-10-01

    A series of experiments was undertaken to measure the recovery efficiency of platinum, palladium and gold from silicate rocks using a sodium peroxide fusion followed by anion exchange separation of the analytes as chloro complexes. Results obtained by graphite furnace atomic absorption spectrometric analysis of standard solutions prepared in dilute HCl or HCl-acidified sodium peroxide solution showed that recoveries were near quantitative. However, when standard solutions were added to an alkaline sodium peroxide solution, which was then acidified, low results were obtained for platinum and gold (46% and 76% respectively). Low and variable results were also obtained when standard solutions were added to a peridotite sample that had been dissolved by the state procedure, and in the analysis of the South African Bureau of Standards certified reference material, SARM 7. Various experiments were undertaken to investigate these low recoveries, but the reason proposed here is the formation of hydroxychloro compounds in alkaline solution which are not, on acidification with HCl, converted quantitatively to the chloro complex necessary for quantitative anion exchange separation. It is concluded that a sodium peroxide fusion followed by an anion-exchange separation does not appear to form the basis of a successful technique for the determination of platinum, palladium and gold in silicate rocks.

  3. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, Rathin; Randhava, Sarabjit S.; Tsai, Shih-Perng

    1997-01-01

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H.sub.2 O.sub.2 laden permeate.

  4. Occupational skin injury by hydrogen peroxide.

    PubMed

    Izu, K; Yamamoto, O; Asahi, M

    2000-01-01

    Hydrogen peroxide is widely used in products such as rocket fuel, bleaching preparations and topical disinfectants. Contact of hydrogen peroxide with the skin can cause severe skin damage. In this report, we describe a case of skin injury induced by hydrogen peroxide. The patient was a 34-year-old man working in a dry cleaning shop. While he was pouring 35% hydrogen peroxide, some of it accidentally splashed over his left shoulder and back, and then an erythema, purpura and vacuolar eruption, similar to bubble wrap, appeared on his left shoulder and down the left side of his back. Histologically, numerous vacuolar structures were observed in the epidermis, dermis and subcutaneous tissue. Coupled with the clinical features, these vacuolar structures were considered as 'oxygen bubbles'. Subcutaneous emphysema was detected by chest X-ray examination. All skin eruptions rapidly healed without scarring by using a steroid ointment. As far as we know, this is the first time such clinical and histological features have been described

  5. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.802... proportions of higher polymers, manufactured by reaction of hydrogen peroxide and acetone. (b) The additive... additive container and any intermediate premix thereof shall bear, in addition to the other...

  6. Process for the production of hydrogen peroxide

    DOEpatents

    Datta, R.; Randhava, S.S.; Tsai, S.P.

    1997-09-02

    An integrated membrane-based process method for producing hydrogen peroxide is provided comprising oxidizing hydrogenated anthraquinones with air bubbles which were created with a porous membrane, and then contacting the oxidized solution with a hydrophilic membrane to produce an organics free, H{sub 2}O{sub 2} laden permeate. 1 fig.

  7. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... flour, and in bread and rolls where standards of identity do not preclude its use, in accordance with... in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per... use: (1) In maturing and bleaching of flour in a quantity not more than sufficient for such...

  8. 21 CFR 172.802 - Acetone peroxides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... flour, and in bread and rolls where standards of identity do not preclude its use, in accordance with... in flour maturing and bleaching; or (2) approximately 0.75 gram of hydrogen peroxide equivalent per... use: (1) In maturing and bleaching of flour in a quantity not more than sufficient for such...

  9. The evolution of benzoyl peroxide therapy.

    PubMed

    Tanghetti, Emil

    2008-11-01

    Since its first use in dermatology last century, benzoyl peroxide (BPO) has undergone a number of reformulations, each enhancing its efficacy, tolerability, or both. Benzoyl peroxide can be used as monotherapy or in combination with oral or topical antibiotics or topical retinoids. Its antimicrobial activity is based on the generation of highly reactive oxygen radicals, a physicochemical effect to which Propionibacterium acnes has not developed resistance. In addition to its nonspecific antimicrobial activity, BPO has keratolytic, comedolytic, and anti-inflammatory activity in acne. Benzoyl peroxide can be added to antibiotic regimens to help maintain bacterial sensitivity to the antibiotic. Additive or synergistic effects of BPO-antibiotic combinations have been demonstrated. Fixed combinations of BPO with either antibiotics or a retinoid recently have become available and may improve compliance. New moisturizing vehicles and stabilized BPO formulations also have added to tolerability and convenience. Benzoyl peroxide may have underappreciated potential to treat noninflammatory acne as monotherapy or in combination with a topical retinoid, an important antibiotic-sparing strategy.

  10. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution... hydrogen peroxide can be determined in distilled water packaged under production conditions (assay to...

  11. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution... hydrogen peroxide can be determined in distilled water packaged under production conditions (assay to...

  12. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution... hydrogen peroxide can be determined in distilled water packaged under production conditions (assay to...

  13. 21 CFR 178.1005 - Hydrogen peroxide solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SANITIZERS Substances Utilized To Control the Growth of Microorganisms § 178.1005 Hydrogen peroxide solution... hydrogen peroxide can be determined in distilled water packaged under production conditions (assay to...

  14. Systems and methods for generation of hydrogen peroxide vapor

    DOEpatents

    Love, Adam H; Eckels, Joel Del; Vu, Alexander K; Alcaraz, Armando; Reynolds, John G

    2014-12-02

    A system according to one embodiment includes a moisture trap for drying air; at least one of a first container and a second container; and a mechanism for at least one of: bubbling dried air from the moisture trap through a hydrogen peroxide solution in the first container for producing a hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above a hydrogen peroxide solution in the second container for producing a hydrogen peroxide vapor. A method according one embodiment includes at least one of bubbling dried air through a hydrogen peroxide solution in a container for producing a first hydrogen peroxide vapor, and passing dried air from the moisture trap into a headspace above the hydrogen peroxide solution in a container for producing a second hydrogen peroxide vapor. Additional systems and methods are also presented.

  15. Intermediate range order in alkaline borate glasses

    NASA Astrophysics Data System (ADS)

    Crupi, C.; Carini, G.; Ruello, G.; D'Angelo, G.

    2016-03-01

    We describe the neutron diffraction patterns of a series of alkaline borate glasses at different metal oxide content. Strong differences are observed in the intermediate range order as a function of the specific alkaline ion and of its concentration. On these results, we propose that the first sharp diffraction peak arises from correlations of atoms of voids and show that the compositional variation of this peak intensity in alkaline borate glasses is due to changes in the distribution of void sizes within the three-dimensional network. We argue that our interpretation in terms of interstitial (empty and/or filled) voids, having different sizes, provides a general explanation for all anomalous behaviours revealed for the first sharp diffraction peak.

  16. Differential regulation of epidermal growth factor receptor by hydrogen peroxide and flagellin in cultured lung alveolar epithelial cells.

    PubMed

    Nishi, Hiroyuki; Maeda, Noriko; Izumi, Shunsuke; Higa-Nakamine, Sayomi; Toku, Seikichi; Kakinohana, Manabu; Sugahara, Kazuhiro; Yamamoto, Hideyuki

    2015-02-05

    In previous studies, we found that stimulation of Toll-like receptor 5 (TLR5) by flagellin induced the activation of mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MAPKAPK-2) through activation of the p38 MAPK pathway in cultured alveolar epithelial A549 cells. Our studies strongly suggested that MAPKAPK-2 phosphorylated epidermal growth factor receptor (EGFR) at Ser1047. It has been reported that phosphorylation of Ser1047 after treatment with tumor necrosis factor α (TNFα) induced the internalization of EGFR. In the present study, we first found that treatment of A549 cells with hydrogen peroxide induced the activation of MAPKAPK-2 and phosphorylation of EGFR at Ser1047 within 30 min. This was different from flagellin treatment because hydrogen peroxide treatment induced the phosphorylation of EGFR at Tyr1173 as well as Ser1047, indicating the activation of EGFR. We also found that KN93, an inhibitor of CaM kinase II, inhibited the hydrogen peroxide-induced phosphorylation of EGFR at Ser1047 through inhibition of the activation of the p38 MAPK pathway. Furthermore, we examined the internalization of EGFR by three different methods. Flow cytometry with an antibody against the extracellular domain of EGFR and biotinylation of cell surface proteins revealed that flagellin, but not hydrogen peroxide, decreased the amount of cell-surface EGFR. In addition, activation of extracellular signal-regulated kinase by EGF treatment was reduced by flagellin pre-treatment. These results strongly suggested that hydrogen peroxide activated the p38 MAPK pathway via activation of CaM kinase II and that flagellin and hydrogen peroxide regulate the functions of EGFR by different mechanisms.

  17. Bromobenzene-induced lethal toxicity in mouse is prevented by pretreatment with zinc sulfate.

    PubMed

    Yoshioka, Hiroki; Fukaya, Shiori; Fukuishi, Nobuyuki; Nagatsu, Akito; Nonogaki, Tsunemasa; Onosaka, Satomi

    2016-07-25

    In the current study, we evaluated the protective effect of zinc (Zn) against bromobenzene (BB) -induced lethal toxicity. We used Zn because this element is known to be an inducer of metallothionein (MT), which is in turn known to serve as an endogenous scavenger of free radicals. We administered Zn (as ZnSO4) at 50 mg/kg subcutaneously once-daily for 3 successive days prior to a single intraperitoneal administration of 1.2 g/kg BB in male ddY mice. Our results showed that pretreatment with Zn completely abolished the BB-induced mortality of mice until 48 h. We also found that pretreatment of mice with Zn significantly decreased the functional marker levels and reduced the histological damage both in liver and kidney as assessed at 18 h post-BB. We also showed that pretreatment with Zn enhanced antioxidative activity, resulting in decreased lipid peroxidation in both liver and kidney. Moreover, BB-induced calcium levels were downregulated by pretreatment with Zn. In addition, Zn-induced MT was decreased in Zn + BB-treated animals, implying that MT was consumed by BB-induced radicals. These findings suggest that prophylaxis with Zn protects mice from BB-induced lethal toxicity by decreasing oxidative stress in liver and kidney, presumably by induction of MT, which scavenges radicals induced by BB exposure.

  18. Pretreatment of Adipose Derived Stem Cells with Curcumin Facilitates Myocardial Recovery via Antiapoptosis and Angiogenesis.

    PubMed

    Liu, Jianfeng; Zhu, Ping; Song, Peng; Xiong, Weiping; Chen, Haixu; Peng, Wenhui; Wang, Shuxia; Li, Shan; Fu, Zhiqing; Wang, Yutang; Wang, Haibin

    2015-01-01

    The poor survival rate of transplanted stem cells in ischemic myocardium has limited their therapeutic efficacy. Curcumin has potent antioxidant property. This study investigates whether prior curcumin treatment protects stem cells from oxidative stress injury and improves myocardial recovery following cells transplantation. Autologous Sprague-Dawley rat adipose derived mesenchymal stem cells (ADSCs) were pretreated with or without curcumin. The hydrogen peroxide/serum deprivation (H2O2/SD) medium was used to mimic the ischemic condition in vitro. Cytoprotective effects of curcumin on ADSCs were evaluated. Curcumin pretreatment significantly increased cell viability and VEGF secretion, and decreased cell injury and apoptosis via regulation of PTEN/Akt/p53 and HO-1 signal proteins expression. The therapeutic potential of ADSCs implantation was investigated in myocardial ischemia-reperfusion injury (IRI) model. Transplantation of curcumin pretreated ADSCs not only resulted in better heart function, higher cells retention, and smaller infarct size, but also decreased myocardial apoptosis, promoted neovascularization, and increased VEGF level in ischemic myocardium. Together, priming of ADSCs with curcumin improved tolerance to oxidative stress injury and resulted in enhancement of their therapeutic potential of ADSCs for myocardial repair. Curcumin pretreatment is a promising adjuvant strategy for stem cells transplantation in myocardial restoration.

  19. Xanthine oxidase-generated hydrogen peroxide is a consequence, not a mediator of cell death.

    PubMed

    Czupryna, Julie; Tsourkas, Andrew

    2012-03-01

    Oxidative stress has been associated with a wide range of diseases including atherosclerosis, cancer and Alzheimer's disease. When present in excessive concentrations, reactive oxygen species (ROS) can cause deleterious effects. This has led to the notion that the anticancer effects of various chemotherapeutics may be mediated, at least in part, by an increase in ROS. To investigate the role of xanthine oxidase (XO), a source of hydrogen peroxide, in cell death, MCF7, HeLa and 293T cells were treated with various cell-death-inducing drugs in the presence and absence of allopurinol, a specific inhibitor of XO. In the absence of allopurinol, each drug led to a time- and concentration-dependent increase in percent DNA fragmentation and ROS levels, regardless of the mechanism of cell death incurred, i.e. caspase dependent and caspase independent. By contrast, pretreatment with allopurinol led to dramatically lower ROS levels in all cases, suggesting that XO is a major contributor to oxidative stress. However, allopurinol did not exhibit a protective effect against cell death. Similarly, the administration of siRNA against XO also did not exhibit a protective effect against cell death. The level of oxidative stress was recorded using the ROS sensor CM-H(2) DCFDA and a ratiometric bioluminescent assay that takes advantage of the increased sensitivity of Firefly luciferase to hydrogen peroxide, compared with a stable variant of Renilla luciferase (RLuc), RLuc8. Overall, these findings suggest that XO-generated hydrogen peroxide, and perhaps hydrogen peroxide in general, is a consequence, but not a mediator of cell death.

  20. Nanotechnology Corrosion Pretreatment for Magnesium Alloys

    DTIC Science & Technology

    2012-08-29

    Pretreatment for Magnesium Alloys AMS-SAE-M-3171, Type IV Replacement on AZ91D Glycolic Nitrate Pickle (GNP) (1 min) PT-60 (3 min) 0 hr SST 1 4 3 2...Nanotechnology Corrosion Pretreatment for Magnesium Alloys Mr. Jules F. Senske and Mr. Daniel Schmidt Army Research Development and...SUBTITLE Nanotechnology Corrosion Pretreatment for Magnesium Alloys 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d

  1. New Drugs for Pretreatment of Organophosphonate Intoxication

    DTIC Science & Technology

    1990-02-20

    COPY A D L£> SRI PROJECT PYU-4681 NEW DRUGS FOR PRETREATMENT OF ORGANOPHOSPHONATE INTOXICATION FINAL REPORT AD-B145 250 Daniel W. Parish, Allen...BB WORK UNIT ACCESSION NO. 099 11. TITLE (indud* Security Oaofficattofl) New Drugs for Pretreatment of Organophosphonate Intoxication...undertaken for the U.S. Army Medical Research and Development Command (MRDC) under Contract DAMD17-88-C-8001, " New Drugs for Pretreatment of

  2. Synthesis and asymmetric resolution of α-azido-peroxides.

    PubMed

    Pramanik, Suman; Ghorai, Prasanta

    2013-08-02

    An unprecedented synthesis of α-azido-peroxides has been developed using an FeCl3-catalyst starting from carbonyl, TMS-azide, and hydroperoxide. Further, a base promoted decomposition of synthesized secondary α-azido-peroxides to provide the corresponding tert-butyl esters has been disclosed. Finally, an asymmetric kinetic resolution of such α-azido-peroxides has also been developed to provide chiral α-azido-peroxides in excellent enantiopurity.

  3. Expanding the crystal chemistry of uranyl peroxides: four hybrid uranyl-peroxide structures containing EDTA.

    PubMed

    Qiu, Jie; Ling, Jie; Sieradzki, Claire; Nguyen, Kevin; Wylie, Ernest M; Szymanowski, Jennifer E S; Burns, Peter C

    2014-11-17

    The first four uranyl peroxide compounds containing ethylenediaminetetra-acetate (EDTA) were synthesized and characterized from aqueous uranyl peroxide nitrate solutions with a pH range of 5-7. Raman spectra demonstrated that reaction solutions that crystallized [NaK15[(UO2)8(O2)8(C10H12O10N2)2(C2O4)4]·(H2O)14] (1) and [Li4K6[(UO2)8(O2)6(C10H12O10N2)2(NO3)6]·(H2O)26] (2) contained excess peroxide, and their structures contained oxidized ethylenediaminetetraacetate, EDTAO2(4-). The solutions from which [K4[(UO2)4(O2)2(C10H13O8N2)2(IO3)2]·(H2O)16] (3) and LiK3[(UO2)4(O2)2(C10H12O8N2)2(H2O)2]·(H2O)18 (4) crystallized contained no free peroxide, and the structures incorporated intact EDTA(4-). In contrast to the large family of uranyl peroxide cage clusters, coordination of uranyl peroxide units in 1-4 by EDTA(4-) or EDTAO2(4-) results in isolated tetramers or dimers of uranyl ions that are bridged by bidentate peroxide groups. Two tetramers are bridged by EDTAO2(4-) to form octamers in 1 and 2, and dimers of uranyl polyhedra are linked through iodate groups in 3 and EDTA(4-) in 4, forming chains in both cases. In each structure the U-O2-U dihedral angle is strongly bent, at ∼140°, consistent with the configuration of this linkage in cage clusters and other recently reported uranyl peroxides.

  4. Laser direct write of planar alkaline microbatteries

    NASA Astrophysics Data System (ADS)

    Arnold, C. B.; Kim, H.; Piqué, A.

    We are developing a laser engineering approach to fabricate and optimize alkaline microbatteries in planar geometries. The laser direct-write technique enables multicapability for adding, removing and processing material and provides the ability to pattern complicated structures needed for fabricating complete microbattery assemblies. In this paper, we demonstrate the production of planar zinc-silver oxide alkaline cells under ambient conditions. The microbattery cells exhibit 1.55-V open-circuit potentials, as expected for the battery chemistry, and show a flat discharge behavior under constant-current loads. High capacities of over 450 μAhcm-2 are obtained for 5-mm2 microbatteries.

  5. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    DOEpatents

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  6. Alkaline Capacitors Based on Nitride Nanoparticles

    NASA Technical Reports Server (NTRS)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  7. Lipid peroxidation induced by indomethacin with horseradish peroxidase and hydrogen peroxide: involvement of indomethacin radicals.

    PubMed

    Miura, Toshiaki; Muraoka, Sanae; Fujimoto, Yukio

    2002-06-01

    Some of the side-effects of using indomethacin (IM) involve damage to the gastric mucosa and liver mitochondria. On the other hand, neutrophils infiltrate inflammatory sites to damage the tissues through the generation of reactive oxygen species by myeloperoxidase. The stomach and intestine have large amounts of peroxidase. These findings suggest that peroxidases are involved in tissue damage induced by IM. To clarify the basis for the tissue damage induced by IM in the presence of horseradish peroxidase (HRP) and H2O2 (HRP-H2O2), lipid peroxidation was investigated. When IM was incubated with liver microsomes in the presence of HRP-H2O2 and ADP-Fe3+, lipid peroxidation was time-dependent. Catalase and desferrioxamine almost completely inhibited lipid peroxidation, indicating that H2O2 and iron are necessary for lipid peroxidation. Of interest, superoxide dismutase strongly inhibited lipid peroxidation, and it also inhibited the formation of bathophenanthroline-Fe2+, indicating that reduction of the ferric ion was due to superoxide (O2-). ESR signals of IM radicals were detected during the interaction of IM with HRP-H2O2. However, the IM radical by itself did not reduce the ferric ion. These results suggest that O2- may be generated during the interaction of IM radicals with H2O2. Ferryl species, which are formed during the reduction of iron by O2-, probably are involved in lipid peroxidation.

  8. Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.; Presley, Derek J.

    2001-01-01

    A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

  9. Impact of pre-treatments on properties of lignocelluloses and their accessibility for a subsequent carboxymethylation.

    PubMed

    Heise, Katja; Rossberg, Christine; Strätz, Juliane; Bäurich, Christian; Brendler, Erica; Keller, Harald; Fischer, Steffen

    2017-04-01

    In this issue, different chemical (alkaline and sulfite pulping, ozonolysis) and mechanical (vibratory ball milling) pre-treatments were utilized for activating wheat straw and beech sawdust prior to carboxymethylation. Detailed analysis by a range of methods, including Klason-lignin, cellulose and hemicellulose quantification, Powder-X-ray diffraction (PXRD) and attenuated total reflection (ATR) IR spectroscopy, enabled the investigation of material alterations. Subsequently, carboxymethylation was carried out with both untreated and activated materials, allowing the evaluation of activation steps by determining degrees of substitution with carboxymethyl groups (DSCM). Moreover, carboxymethylation conditions were optimized, realizing high DSCM of up to 1.05. Results further revealed that ball milling enhanced the subsequent conversion; whereas chemical pre-treatments did not effectively increase material accessibilities. Further studies on chemically untreated materials emphasized that a highly reactive surface was already generated in the course of the carboxymethylation, inter alia through the concomitant dissolution of matrix components.

  10. MEASUREMENT AND MODELING OF THE DRY DEPOSITION OF PEROXIDES

    EPA Science Inventory

    Measurements of the dry deposition velocity (Vd) of hydrogen peroxide (H2O2) and total organic peroxides (ROOH) were made during four experiments at three forested sites. Details and uncertainties associated with the measurement of peroxide...

  11. Impact of hydrogen peroxide as a soil amendment on nasturtiums

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrogen peroxide, H2O2, is a highly reactive oxidizing agent naturally occurring in plants and animals. Plants produce hydrogen peroxide to destroy either their infected plant cells or the pathogens within their cells. Hydrogen peroxide also acts as a stress signal to plants. It is approved for c...

  12. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  13. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half....

  14. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half. [71 FR...

  15. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  16. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  17. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  18. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half....

  19. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half....

  20. 49 CFR 172.552 - ORGANIC PEROXIDE placard.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false ORGANIC PEROXIDE placard. 172.552 Section 172.552... SECURITY PLANS Placarding § 172.552 ORGANIC PEROXIDE placard. (a) Except for size and color, the ORGANIC... background on the ORGANIC PEROXIDE placard must be red in the top half and yellow in the lower half. The...

  1. 49 CFR 172.427 - ORGANIC PEROXIDE label.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false ORGANIC PEROXIDE label. 172.427 Section 172.427... SECURITY PLANS Labeling § 172.427 ORGANIC PEROXIDE label. (a) Except for size and color, the ORGANIC... on the ORGANIC PEROXIDE label must be red in the top half and yellow in the lower half....

  2. Effect of biomass pretreatment on the product distribution and composition resulting from the hydrothermal liquefaction of short rotation coppice willow.

    PubMed

    Grigoras, I F; Stroe, R E; Sintamarean, I M; Rosendahl, L A

    2017-05-01

    A major challenge for the implementation of hydrothermal liquefaction (HTL) as a continuous process is the formulation of lignocellulosic feedstock, which is prone to phase separation into water and biomass parts when pressurized. One approach to remedy such phase separation is to reduce the dry matter content; however, as this approach is detrimental to process cost efficiency, designing an appropriate pretreatment step to ensure pumpability at high dry matter content is preferable. This paper evaluated the effect of various pretreatment methods on product distribution and composition resulting from the HTL of willow and proposes short rotation coppice as an alternative biomass feedstock for biofuels production. Alkaline-thermal pretreatment, besides making high dry matter pumpable feedstock slurries, also led to an increase in the production of the bio-crude product with an oxygen content lower than 8wt% and a higher concentration of aromatics and phenolic compounds.

  3. The effect of hydrogen peroxide concentration and solid loading on the fractionation of biomass in formic acid.

    PubMed

    Dussan, K; Girisuta, B; Haverty, D; Leahy, J J; Hayes, M H B

    2014-10-13

    This study investigated the fractionation of biomass using a decomposing mixture of hydrogen peroxide-formic acid as a pretreatment for the biorefining of Miscanthus × giganteus and of sugarcane bagasse. The main parameters investigated were the hydrogen peroxide concentration (2.5, 5.0 and 7.5 wt%) and biomass loading (5.0 and 10.0 wt%). At the highest hydrogen peroxide concentration used (7.5 wt%), the energy released by the decomposition of the H2O2 could heat the reaction mixture up to 180 °C in a short time (6-16 min). As a result, highly delignified pulps, with lignin removal as high as 92 wt%, were obtained. This delignification process also solubilised a significant amount of pentosan (82-98 wt%) from the initial biomass feedstock, and the resulting pulp had a high cellulosic content (92 wt%). The biomass loading only affected the reaction rate of hydrogen peroxide decomposition. Various analytical methods, including Fourier transform infrared spectroscopy, and thermogravimetric and elemental analyses, characterized the lignin obtained.

  4. Atypical adaptive and cross-protective responses against peroxide killing in a bacterial plant pathogen, Agrobacterium tumefaciens.

    PubMed

    Vattanaviboon, Paiboon; Eiamphungporn, Warawan; Mongkolsuk, Skorn

    2003-10-01

    Physiological adaptive and cross-protection responses to oxidants were investigated in Agrobacterium tumefaciens. Exposure of A. tumefaciens to sublethal concentrations of H2O2 induced adaptive protection to lethal concentrations of H2O2. Similar treatments with organic peroxide and menadione did not produce adaptive protection to subsequent exposure to lethal concentrations of these oxidants. Pretreatment of A. tumefaciens with an inducing concentration of menadione conferred cross-protection against H2O2, but not to tert-butyl hydroperoxide (tBOOH), killing. The menadione induced cross-protection to H2O2 was due to the compound's ability to highly induce the peroxide scavenging enzyme, catalase. The levels of catalase directly correlated with the bacterium's ability to survive H2O2 treatment. Some aspects of the oxidative stress response of A. tumefaciens differ from other bacteria, and these differences may be important in plant/microbe interactions.

  5. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    PubMed Central

    Schwalfenberg, Gerry K.

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine. PMID:22013455

  6. The alkaline diet: is there evidence that an alkaline pH diet benefits health?

    PubMed

    Schwalfenberg, Gerry K

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

  7. Assessment of commercially available ion exchange materials for cesium removal from highly alkaline wastes

    SciTech Connect

    Brooks, K.P.; Kim, A.Y.; Kurath, D.E.

    1996-04-01

    Approximately 61 million gallons of nuclear waste generated in plutonium production, radionuclide removal campaigns, and research and development activities is stored on the Department of Energy`s Hanford Site, near Richland, Washington. Although the pretreatment process and disposal requirements are still being defined, most pretreatment scenarios include removal of cesium from the aqueous streams. In many cases, after cesium is removed, the dissolved salt cakes and supernates can be disposed of as LLW. Ion exchange has been a leading candidate for this separation. Ion exchange systems have the advantage of simplicity of equipment and operation and provide many theoretical stages in a small space. The organic ion exchange material Duolite{trademark} CS-100 has been selected as the baseline exchanger for conceptual design of the Initial Pretreatment Module (IPM). Use of CS-100 was chosen because it is considered a conservative, technologically feasible approach. During FY 96, final resin down-selection will occur for IPM Title 1 design. Alternate ion exchange materials for cesium exchange will be considered at that time. The purpose of this report is to conduct a search for commercially available ion exchange materials which could potentially replace CS-100. This report will provide where possible a comparison of these resin in their ability to remove low concentrations of cesium from highly alkaline solutions. Materials which show promise can be studied further, while less encouraging resins can be eliminated from consideration.

  8. Effect of carbamide peroxide and hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings.

    PubMed

    Rostein, I; Cohenca, N; Mor, C; Moshonov, J; Stabholz, A

    1995-12-01

    The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings was tested. Ninety IRM samples were treated with either 10% carbamide peroxide, 10% hydrogen peroxide or phosphate buffer which served as control. Treatment consisted of placing the samples in a dry incubator at 37 degrees C for 1, 3 or 7 days. At each time point, the samples were removed from the test solutions, dried and prepared for surface scanning electron microscopy and energy dispersive spectrometric analysis. After 3 days, 10% carbamide peroxide significantly reduced the zinc oxide levels as compared to the 10% hydrogen peroxide group (<0.01) and the controls (p<0.01). 10% hydrogen peroxide reduced the zinc oxide levels similarly to the control. No significant changes in the zinc oxide levels were found between 3 and 7 days in any of the groups tested. Microscopy examination of the carbamide peroxide group revealed granular surface with well defined crystalline areas. In the hydrogen peroxide group, numerous cracks with multiple sun burst-like areas were found. At the macroscopic level, the samples of this group appeared cracked and more swollen, as compared to controls and samples treated with carbamide peroxide. In conclusion, both 10% carbamide peroxide and 10% hydrogen peroxide altered the surface morphology and the zinc oxide levels of IRM fillings, but their modes of action differed.

  9. Negative Electrode For An Alkaline Cell

    DOEpatents

    Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

    1998-07-14

    The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

  10. Alkaline electrochemical cells and method of making

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  11. Kinetics of the alkaline hydrolysis of nitrocellulose.

    PubMed

    Christodoulatos, C; Su, T L; Koutsospyros, A

    2001-01-01

    Cellulose nitrate (nitrocellulose) is an explosive solid substance used in large quantities in various formulations of rocket and gun propellants. Safe destruction of nitrocellulose can be achieved by alkaline hydrolysis, which converts it to biodegradable products that can then be treated by conventional biological processes. The kinetics of the alkaline hydrolysis of munitions-grade nitrocellulose in sodium hydroxide solutions were investigated in completely mixed batch reactors. Experiments were conducted using solutions of alkaline strength ranging from 0.1 to 15% by mass and temperatures in the range of 30 to 90 degrees C. Regression analysis of the kinetic data revealed that alkaline hydrolysis of nitrocellulose is of the order 1.0 and 1.5 with respect to nitrocellulose and hydroxide concentration, respectively. The activation energy of the hydrolysis reaction was found to be 100.9 kJ/mol with a preexponential Arrhenius constant of 4.73 x 10(13). Nitrite and nitrate, in a 3:1 ratio, were the primary nitrogen species present in the posthydrolysis solution. The kinetic information is pertinent to the development and optimization of nitrocellulose chemical-biological treatment systems.

  12. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS

    EPA Science Inventory

    The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-b...

  13. ISSUES WITH ALKALINE TREATMENT OF SLUDGE

    EPA Science Inventory

    This presentation begins with a discussion of the use of lime and other alkaline materials from the very earliest times to the present for killing bacteria, viruses and parasites and for controlling odors in wastewaters and sludge. It answers the question "How did EPA arrive at i...

  14. Pre-treatment Effects on Coral Skeletal δ 13C and δ 18O

    NASA Astrophysics Data System (ADS)

    Grottoli, A. G.; Gibb, O.; Wellington, G. M.

    2003-12-01

    Pre-treatment protocols for coral skeletal stable carbon (δ 13C) and oxygen (δ 18O) isotope analyses include no treatment, bleach (NaOH), hydrogen peroxide (H2O2), or vacuum roasting prior to analysis. Such pre-treatments are used to remove organic material prior to isotopic analyses. Researchers that do not pre-treat samples argue that such treatments result in non-linear shifts in coral skeletal δ 13C and δ 18O thus increasing the analytical error in the δ 13C and δ 18O values. Vacuum roasting does cause isotopic shifts and is no longer practiced. However, both no pre-treatment and pre-treatment (with either NaOH or H2O2) coral δ 13C and δ 18O values continue to be published in the literature. In all previous studies of the effects of NaOH and H2O2 pre-treatments on coral δ 13C and δ 18O, the samples sizes were typically small and the exact time interval being sampled and compared was not specifically controlled. Here, we evaluated the effects of NaOH and H2O2 pre-treatments on coral skeletal δ 13C and δ 18O in Pavona clavus and Pavona gigantea from Panama, and Porites compressa from Hawaii. In Panama, at least five coral fragments from five different colonies of each species were stained on November 1978 and April 1979 then collected in November 1979. In Hawaii, at least five coral fragments from five different colonies at 1.7 and 7 m depths were stained on 1 September and 21 November 1996 then collected 2 March 1997. For each fragment, a bulk skeletal sample was extracted representing the entire growth interval between the two stain lines yielding at least 24 mg of material. Sampling between the stain lines ensured that all of the fragments from a given site and species were sampled over the same time interval and avoided any potential contamination from the tissue layer. Eight milligram subsamples from each fragment were subjected to 24 hours of the following treatments: NaOH, H2O2, Milli-Q filtered water (control), or no pre-treatment (control

  15. Alkaline earth metal catalysts for asymmetric reactions.

    PubMed

    Kobayashi, Shū; Yamashita, Yasuhiro

    2011-01-18

    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  16. Potential of Ceiba pentandra (L.) Gaertn. (kapok fiber) as a resource for second generation bioethanol: effect of various simple pretreatment methods on sugar production.

    PubMed

    Tye, Ying Ying; Lee, Keat Teong; Wan Abdullah, Wan Nadiah; Leh, Cheu Peng

    2012-07-01

    The importance of bioethanol currently has increased tremendously as it can reduce the total dependency on fossil-fuels, especially gasoline, in the transportation sector. In this study, Ceiba pentandra (kapok fiber) was introduced as a new resource for bioethanol production. The results of chemical composition analysis showed that the cellulose (alpha- and beta-) contents were 50.7%. The glucose composition of the fiber was 59.8%. The high glucose content indicated that kapok fiber is a potential substrate for bioethanol production. However, without a pretreatment, the kapok fiber only yielded 0.8% of reducing sugar by enzymatic hydrolysis. Thus, it is necessary to pre-treat the kapok fiber prior to hydrolysis. Taking into account environmentally friendliness, only simple pretreatments with minimum chemical or energy consumption was considered. It was interesting to see that by adopting merely water, acid and alkaline pretreatments, the yield of reducing sugar was increased to 39.1%, 85.2% and >100%, respectively.

  17. Wash water waste pretreatment system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Investigations were completed on wash waters based on each candidate personal cleansing agent. Evaluations of coagulants, antifoam agents, and the effect of promising antifoams on the chemical precipitation were included. Based on these evaluations two candidate soaps as well as their companion antifoam agents were selected for further work. Operating parameters included the effect of soap concentration, ferric chloride concentration, duration of mixing, and pore size of depth filters on the degree of soap removal. The effect of pressure on water flow through filter cartridges and on the rate of decline of water flow was also investigated. The culmination of the program was the recommendation of a pretreatment concept based on chemical precipitation followed by pressure filtration.

  18. Materials Compatibility in High Test Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Gostowski, Rudy

    1999-01-01

    Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

  19. The lipid peroxidation in breast cancer patients.

    PubMed

    Kedzierska, Magdalena; Olas, Beata; Wachowicz, Barbara; Jeziorski, Arkadiusz; Piekarski, Janusz

    2010-06-01

    The aim of our study was to estimate oxidative stress (by using different biomarkers of lipid peroxidation--isoprostanes and thiobarbituric acid reactive substances (TBARS)) in patients with invasive breast cancer, patients with benign breast diseases and in a control group. We observed a statistically increased level of TBARS in plasma and isoprostanes in urine of patients with invasive breast cancer in comparison with a control group. The concentration of tested biomarkers in plasma or urine from patients with invasive breast cancer was also higher than in patients with benign breast diseases. Moreover, the levels of tested markers in patients with benign breast diseases and in a control group did not differ. Considering the data presented in this study, we suggest that free radicals induce peroxidation of unsaturated fatty acid in patients with breast cancer.

  20. Crystal structure of rubidium peroxide ammonia disolvate.

    PubMed

    Grassl, Tobias; Korber, Nikolaus

    2017-02-01

    The title compound, Rb2O2·2NH3, has been obtained as a reaction product of rubidium metal dissolved in liquid ammonia and glucuronic acid. As a result of the low-temperature crystallization, a disolvate was formed. To our knowledge, only one other solvate of an alkali metal peroxide is known: Na2O2·8H2O has been reported by Grehl et al. [Acta Cryst. (1995), C51, 1038-1040]. We determined the peroxide bond length to be 1.530 (11) Å, which is in accordance with the length reported by Bremm & Jansen [Z. Anorg. Allg. Chem. (1992), 610, 64-66]. One of the ammonia solvate molecules is disordered relative to a mirror plane, with 0.5 occupancy for the corresponding nitrogen atom.

  1. Crystal structure of rubidium peroxide ammonia disolvate

    PubMed Central

    Grassl, Tobias; Korber, Nikolaus

    2017-01-01

    The title compound, Rb2O2·2NH3, has been obtained as a reaction product of rubidium metal dissolved in liquid ammonia and glucuronic acid. As a result of the low-temperature crystallization, a disolvate was formed. To our knowledge, only one other solvate of an alkali metal peroxide is known: Na2O2·8H2O has been reported by Grehl et al. [Acta Cryst. (1995), C51, 1038–1040]. We determined the peroxide bond length to be 1.530 (11) Å, which is in accordance with the length reported by Bremm & Jansen [Z. Anorg. Allg. Chem. (1992), 610, 64–66]. One of the ammonia solvate molecules is disordered relative to a mirror plane, with 0.5 occupancy for the corresponding nitrogen atom. PMID:28217342

  2. An upper limit for stratospheric hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Chance, K. V.; Traub, W. A.

    1984-01-01

    It has been postulated that hydrogen peroxide is important in stratospheric chemistry as a reservoir and sink for odd hydrogen species, and for its ability to interconvert them. The present investigation is concerned with an altitude dependent upper limit curve for stratospheric hydrogen peroxide, taking into account an altitude range from 21.5 to 38.0 km for January 23, 1983. The data employed are from balloon flight No. 1316-P, launched from the National Scientific Balloon Facility (NSBF) in Palestine, Texas. The obtained upper limit curve lies substantially below the data reported by Waters et al. (1981), even though the results are from the same latitude and are both wintertime measurements.

  3. Hydrogen Peroxide: A Potential Wound Therapeutic Target.

    PubMed

    Zhu, Guanya; Wang, Qi; Lu, Shuliang; Niu, Yiwen

    2017-04-05

    Hydrogen peroxide (H2O2) is a topical antiseptic used in wound cleaning which kills pathogens through oxidation burst and local oxygen production. Hydrogen peroxide had been reported to be a reactive biochemical molecule synthesized by various cells which influences biological behavior through multiple mechanisms: alterations of membrane potential, generation of new molecules and changing intracellular redox balance which results in activation or inactivation of different signaling transduction pathways. Contrary to the traditional viewpoint that H2O2 probably impairs tissue through its high oxidative property, however, a proper level of H2O2 is considered as an important requirement for normal wound healing. Although the present clinical use of H2O2 is still limited to the elimination of microbial contamination and sometimes hemostasis, better understanding towards the sterilization ability and cell behavior regulatory function of H2O2 within wound will enhance the potential to exogenously augment and manipulate healing.

  4. Crystal structure of alkaline cellulase K: insight into the alkaline adaptation of an industrial enzyme.

    PubMed

    Shirai, T; Ishida, H; Noda, J; Yamane, T; Ozaki, K; Hakamada, Y; Ito, S

    2001-07-27

    The crystal structure of the catalytic domain of alkaline cellulase K was determined at 1.9 A resolution. Because of the most alkaliphilic nature and it's highest activity at pH 9.5, it is used commercially in laundry detergents. An analysis of the structural bases of the alkaliphilic character of the enzyme suggested a mechanism similar to that previously proposed for alkaline proteases, that is, an increase in the number of Arg, His, and Gln residues, and a decrease in Asp and Lys residues. Some ion pairs were formed by the gained Arg residues, which is similar to what has been found in the alkaline proteases. Lys-Asp ion pairs are disfavored and partly replaced with Arg-Asp ion pairs. The alkaline adaptation appeared to be a remodeling of ion pairs so that the charge balance is kept in the high pH range.

  5. Microwave Pretreatment For Hydrolysis Of Cellulose

    NASA Technical Reports Server (NTRS)

    Cullingford, Hatice S.; George, Clifford E.; Lightsey, George R.

    1993-01-01

    Microwave pretreatment enhances enzymatic hydrolysis of cellulosic wastes into soluble saccharides used as feedstocks for foods, fuels, and other products. Low consumption of energy, high yield, and low risk of proposed hydrolysis process incorporating microwave pretreatment makes process viable alternative to composting.

  6. Hydrogen peroxide induces apoptosis via a mitochondrial pathway in chondrocytes

    NASA Astrophysics Data System (ADS)

    Zhuang, Cai-ping; Liang, Qian; Wang, Xiao-ping; Chen, Tong-sheng

    2012-03-01

    The degenerative joint disease such as osteoarthritis (OA) is closely associated with the death of chondrocytes in apoptosis fashion. Hydrogen peroxide (H2O2), higher expression following acute damage in OA patients, has been shown to be up-regulated during apoptosis in a bulk of experimental models. This study was aimed to explore the mechanism of H2O2-induced rabbit chondrocytes apoptosis. Articular cartilage was biopsied from the joints of 6 weeks old New Zealand rabbits. Cell Counting Kit (CCK-8) assay was used to assess the inhibitory effect of H2O2 on cell viability. H2O2 treatment induced a remarkable reduction of cell viability. We used flow cytometry to assess the form of cell death with Annexin-V/PI double staining, and found that H2O2 treatment induced apoptosis in a dose-and time-dependent manner. Exposure of chondrocytes to 1.5 mM of H2O2 for 2 h induced a burst apoptosis that can be alleviated by N-acetyl cysteine (NAC) pretreatment, an anti-oxidant amino-acid derivative. Loss of mitochondria membrane potential (▵Ψm) was evaluated using confocal microscopy imaging and flow cytometry (FCM). H2O2 treatment induced a marked reduction of ▵Ψm, and the abrupt disappearance of ▵Ψm occurred within 5 minutes. These results indicate that H2O2 induces a rapid apoptosis via a mitochondrial pathway in rabbit chondrocytes.

  7. Innovative pretreatment strategies for biogas production.

    PubMed

    Patinvoh, Regina J; Osadolor, Osagie A; Chandolias, Konstantinos; Sárvári Horváth, Ilona; Taherzadeh, Mohammad J

    2017-01-01

    Biogas or biomethane is traditionally produced via anaerobic digestion, or recently by thermochemical or a combination of thermochemical and biological processes via syngas (CO and H2) fermentation. However, many of the feedstocks have recalcitrant structure and are difficult to digest (e.g., lignocelluloses or keratins), or they have toxic compounds (such as fruit flavors or high ammonia content), or not digestible at all (e.g., plastics). To overcome these challenges, innovative strategies for enhanced and economically favorable biogas production were proposed in this review. The strategies considered are commonly known physical pretreatment, rapid decompression, autohydrolysis, acid- or alkali pretreatments, solvents (e.g. for lignin or cellulose) pretreatments or leaching, supercritical, oxidative or biological pretreatments, as well as combined gasification and fermentation, integrated biogas production and pretreatment, innovative biogas digester design, co-digestion, and bio-augmentation.

  8. Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

    SciTech Connect

    Rudisill, T.S.

    1999-08-11

    Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

  9. s-Ethyl Cysteine and s-Methyl Cysteine Protect Human Bronchial Epithelial Cells Against Hydrogen Peroxide Induced Injury.

    PubMed

    Hsia, Te-chun; Yin, Mei-chin

    2015-09-01

    Protective effects and actions from s-ethyl cysteine (SEC) and s-methyl cysteine (SMC) for BEAS-2B cells were examined. BEAS-2B cells were pretreated with SEC or SMC at 4, 8, or 16 μmol/L, and followed by hydrogen peroxide (H2 O2 ) treatment. Data showed that H2 O2 enhanced Bax, caspase-3 and caspase-8 expression, and declined Bcl-2 expression. However, SEC or SMC dose-dependently decreased caspase-3 expression and reserved Bcl-2 expression. H2 O2 increased reactive oxygen species (ROS) production, and lowered glutathione level, glutathione peroxide, and glutathione reductase activities in BEAS-2B cells. SEC or SMC pretreatments reduced ROS generation, and maintained glutathione redox cycle in those cells. H2 O2 upregulated the expression of both p47(phox) and gp91(phox) . SEC and SMC downregulated p47(phox) expression. SEC or SMC at 8 and 16 μmol/L decreased H2 O2 -induced release of inflammatory cytokines. H2 O2 stimulated the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase. SEC and SMC pretreatments dose-dependently downregulated NF-κB p65 and p-p38 expression. Pyrrolidine dithiocarbamate or SB203580 inhibited NF-κB activation and p38 phosphorylation; thus, SEC or SMC pretreatments failed to affect protein expression of these factors. These novel findings suggest that SEC or SMC could protect bronchial cells and benefit respiratory epithelia stability and functions.

  10. Proteomics reveals the overlapping roles of hydrogen peroxide and nitric oxide in the acclimation of citrus plants to salinity.

    PubMed

    Tanou, Georgia; Job, Claudette; Rajjou, Loïc; Arc, Erwann; Belghazi, Maya; Diamantidis, Grigorios; Molassiotis, Athannasios; Job, Dominique

    2009-12-01

    Hydrogen peroxide (H(2)O(2)) and nitric oxide (*NO) are key reactive species in signal transduction pathways leading to activation of plant defense against biotic or abiotic stress. Here, we investigated the effect of pre-treating citrus plants (Citrus aurantium L.) with either of these two molecules on plant acclimation to salinity and show that both pre-treatments strongly reduced the detrimental phenotypical and physiological effects accompanying this stress. A proteomic analysis disclosed 85 leaf proteins that underwent significant quantitative variations in plants directly exposed to salt stress. A large part of these changes was not observed with salt-stressed plants pre-treated with either H(2)O(2) or sodium nitroprusside (SNP; a *NO-releasing chemical). We also identified several proteins undergoing changes either in their oxidation (carbonylation; 40 proteins) and/or S-nitrosylation (49 proteins) status in response to salinity stress. Both H(2)O(2) and SNP pre-treatments before salinity stress alleviated salinity-induced protein carbonylation and shifted the accumulation levels of leaf S-nitrosylated proteins to those of unstressed control plants. Altogether, the results indicate an overlap between H(2)O(2)- and *NO-signaling pathways in acclimation to salinity and suggest that the oxidation and S-nitrosylation patterns of leaf proteins are specific molecular signatures of citrus plant vigour under stressful conditions.

  11. Trypanosoma rangeli: an alkaline ecto-phosphatase activity is involved with survival and growth of the parasite.

    PubMed

    Dos-Santos, André L A; Dick, Claudia F; Silveira, Thaís S; Fonseca-de-Souza, André L; Meyer-Fernandes, José R

    2013-10-01

    The aim of this work was to investigate whether an alkaline ecto-phosphatase activity is present in the surface of Trypanosoma rangeli. Intact short epimastigote forms were assayed for ecto-phosphatase activity to study kinetics and modulators using β-glycerophosphate (β-GP) and p-nitrophenyl phosphate (pNPP) as substrates. Its role in parasite development and differentiation was also studied. Competition assays using different proportions of β-GP and pNPP evidenced the existence of independent and non-interacting alkaline and acid phosphatases. Hydrolysis of β-GP increased progressively with pH, whereas the opposite was evident using pNPP. The alkaline enzyme was inhibited by levamisole in a non-competitive fashion. The Ca(2+) present in the reaction medium was enough for full activity. Pretreatment with PI-PLC decreased the alkaline but not the acid phosphatase evidence that the former is catalyzed by a GPI-anchored enzyme, with potential intracellular signaling ability. β-GP supported the growth and differentiation of T. rangeli to the same extent as high orthophosphate (Pi). Levamisole at the IC50 spared significantly parasite growth when β-GP was the sole source of Pi and stopped it in the absence of β-GP, indicating that the alkaline enzyme can utilize phosphate monoesters present in serum. These results demonstrate the existence of an alkaline ecto-phosphatase in T. rangeli with selective requirements and sensitivity to inhibitors that participates in key metabolic processes in the parasite life cycle.

  12. The sulphate-reduction alkalinity pump tested

    NASA Astrophysics Data System (ADS)

    Meister, Patrick; Petrishcheva, Elena

    2016-04-01

    Carbonate precipitation has been suggested to be induced by alkalinity increase during sulphate reduction under anoxic conditions. This mechanism may explain the formation of carbonate deposits in shallow marine environments, either within a redox stratified sediment inhabited by phototrophic microbial mats or in shallow water within the photic zone where sulphidic water is upwelling onto the shelf. The alkalinity pump may work as long as the sulphide is not reoxidized to sulphate, a process that would acidify the surrounding. The alkalinity effect of sulphate reduction was recently tested by Aloisi (2008) for microbial mats using a model approach. He found that sulphate reduction does not significantly increase or even decrease carbonate saturation and is unlikely to have played a significant role through Earth history. The model considers many environmental factors, including the effect of carbonate precipitation itself on the carbonate equilbrium and on the alkalinity. We used a modified version of Aloisi's (2008) model to simulate the saturation states of aragonite, calcite and dolomite without the effects of carbonate precipitation. This is necessary to evaluate the effect of microbial metabolisms exclusively on carbonate saturation, since carbonate precipitation is only the consequence, but not the cause of oversaturation. First results show that the saturation state is increased in the zone of phototrophic CO2 uptake. In contrast, the saturation state is strongly decreased in the zone where dissolved oxygen overlaps with dissolved sulphide. Aerobic sulphide oxidation consumes most of the HS- and dissipates most of the alkalinity produced in the sulphate reduction zone below. Hence, our results are consistent with the findings of Aloisi (2008), and they even more clearly show that sulphate reduction does not induce carbonate precipitation nor contributes to carbonate precipitation in combination with phototrophic CO2 uptake. The alkalinity effect of sulphate

  13. [Leucocyte alkaline phosphatase in normal and pathological pregnancy (author's transl)].

    PubMed

    Stark, K H; Zaki, I; Sobolewski, K

    1981-01-01

    The activities of leucocyte alkaline phosphatase were determined in 511 patients with normal and pathological pregnancy. Mean values were compared and the enzyme followed up, and the conclusion was drawn that leucocyte alkaline phosphatase was no safe indicator of foetal condition. No direct relationship were found to exist between leucocyte alkaline phosphatase, total oestrogens, HSAP, HLAP, HPL, and oxytocinase.

  14. Chemical equilibria in the binary and ternary uranyl(VI)-hydroxide-peroxide systems.

    PubMed

    Zanonato, Pier Luigi; Di Bernardo, Plinio; Grenthe, Ingmar

    2012-03-28

    The composition and equilibrium constants of the complexes formed in the binary U(VI)-hydroxide and the ternary U(VI)-hydroxide-peroxide systems have been studied using potentiometric and spectrophotometric data at 25 °C in a 0.100 M tetramethylammonium nitrate medium. The data for the binary U(VI) hydroxide complexes were in good agreement with previous studies. In the ternary system two complexes were identified, [UO(2)(OH)(O(2))](-) and [(UO(2))(2)(OH)(O(2))(2)](-). Under our experimental conditions the former is predominant over a broad p[H(+)] region from 9.5 to 11.5, while the second is found in significant amounts at p[H(+)] < 10.5. The formation of the ternary peroxide complexes results in a strong increase in the molar absorptivity of the test solutions. The absorption spectrum for [(UO(2))(2)(OH)(O(2))(2)](-) was resolved into two components with peaks at 353 and 308 nm with molar absorptivity of 16200 and 20300 M(-1) cm(-1), respectively, suggesting that the electronic transitions are dipole allowed. The molar absorptivity of [(UO(2))(OH)(O(2))](-) at the same wave lengths are significantly lower, but still about one to two orders of magnitude larger than the values for UO(2)(2+)(aq) and the binary uranyl(VI) hydroxide complexes. It is of interest to note that [(UO(2))(OH)(O(2))](-) might be the building block in cluster compounds such as [UO(2)(OH)(O(2))](60)(60-) studied by Burns et al. (P. C. Burns, K. A. Kubatko, G. Sigmon, B. J. Fryer, J. E. Gagnon, M. R. Antonio and L. Soderholm, Angew. Chem. 2005, 117, 2173-2177). Speciation calculations using the known equilibrium constants for the U(vi) hydroxide and peroxide complexes show that the latter are important in alkaline solutions even at very low total concentrations of peroxide, suggesting that they may be involved when the uranium minerals Studtite and meta-Studtite are formed by α-radiolysis of water. Radiolysis will be much larger in repositories for spent nuclear fuel where hydrogen peroxide

  15. Batch and dynamic biosorption of basic dyes from binary solutions by alkaline-treated cypress cone chips.

    PubMed

    Fernandez, M E; Nunell, G V; Bonelli, P R; Cukierman, A L

    2012-02-01

    A simple alkaline pre-treatment of Cupressus sempervirens cone chips was performed to improve their biosorption capacity towards methylene blue and rhodamine B from aqueous solutions, in batch and continuous modes. Biosorption kinetics were determined from single and binary dyes solutions, and properly described by the pseudo-second-order rate model. Experimental single-dye equilibrium isotherms fitted the Langmuir-Freundlich model, with maximum biosorption capacities of 0.68mmol/g for methylene blue and 0.50mmol/g for rhodamine B. Single-dye dynamic biosorption showed that breakthrough time for methylene blue biosorption was almost four times longer than for rhodamine B and that the alkaline modification of the chips greatly improved the biosorption performance. Competitive dynamic biosorption demonstrated the preference of the modified cone chips for biosorbing methylene blue, confirmed by the exit concentration overshoots obtained in the breakthrough curves of rhodamine B.

  16. Enhancement of methane production in mesophilic anaerobic digestion of secondary sewage sludge by advanced thermal hydrolysis pretreatment.

    PubMed

    Abelleira-Pereira, Jose M; Pérez-Elvira, Sara I; Sánchez-Oneto, Jezabel; de la Cruz, Roberto; Portela, Juan R; Nebot, Enrique

    2015-03-15

    Studies on the development and evolution of anaerobic digestion (AD) pretreatments are nowadays becoming widespread, due to the outstanding benefits that these processes could entail in the management of sewage sludge. Production of sewage sludge in wastewater treatment plants (WWTPs) is becoming an extremely important environmental issue. The work presented in this paper is a continuation of our previous studies with the aim of understanding and developing the advanced thermal hydrolysis (ATH) process. ATH is a novel AD pretreatment based on a thermal hydrolysis (TH) process plus hydrogen peroxide (H2O2) addition that takes advantage of a peroxidation/direct steam injection synergistic effect. The main goal of the present research was to compare the performance of TH and ATH, conducted at a wide range of operating conditions, as pretreatments of mesophilic AD with an emphasis on methane production enhancement as a key parameter and its connection with the sludge solubilization. Results showed that both TH and ATH patently improved methane production in subsequent mesophilic BMP (biochemical methane potential) tests in comparison with BMP control tests (raw secondary sewage sludge). Besides other interesting results and discussions, a promising result was obtained since ATH, operated at temperature (115 °C), pretreatment time (5 min) and pressure (1 bar) considerably below those typically used in TH (170 °C, 30 min, 8 bar), managed to enhance the methane production in subsequent mesophilic BMP tests [biodegradability factor (fB) = cumulative CH4production/cumulative CH4production (Control) = 1.51 ± 0.01] to quite similar levels than conventional TH pretreatment [fB = 1.52 ± 0.03].

  17. Thermotolerance and antioxidant systems in Agrostis stolonifera: involvement of salicylic acid, abscisic acid, calcium, hydrogen peroxide, and ethylene.

    PubMed

    Larkindale, Jane; Huang, Bingru

    2004-04-01

    This study investigated whether pre-treating plants with specific putative signaling components and heat acclimation would induce tolerance of a cool-season grass, creeping bentgrass (Agrostis stolonifera var. palustris), to subsequent heat stress and whether thermotolerance induction of those pretreatments was associated with the regulation of antioxidant regenerating enzymes. The treatments included foliar application of salicylic acid (SA), abscisic acid (ABA), calcium chloride (CaCl2), hydrogen peroxide (H2O2), 1-aminocyclopropane-1-carboxylic acid (ACC, a precursor of ethylene prior to the exposure of plants to heat stress (35 degrees C) in a growth chamber. Physiological measurements including turf quality, leaf photosynthetic rate, and levels of oxidative damage demonstrated that all treatments increased heat tolerance. The better heat tolerance for pre-treated plants as compared to controls was related to the protection of oxidative damage under heat stress. APX activity increased over the first 2 days and 5 days of heating for ACC and CaCl2 respectively, but for only 12 h for H2O2. SA and ABA pre-treatments had no effects on APX activity earlier, but maintained APX activity at a significantly higher level than in controls after 24 h of heating. SA and ABA pre-treatments had no effects on POX activity. ACC treatment significantly increased POX activity. Pre-treatment with CaCl2, H2O2, and HA reduced POX activity, particularly during the later phase of heating. Plants treated with SA, CaCl2, H2O2 and HA had lower CAT activity than their control plants prior to heating and within 48 h of heat stress. ABA and ACC pre-treatments maintained higher CAT activity than the controls after 48 h of heating. ACC, CaCl2, or HA pre-treatments increased SOD activity only before 5 days of heat stress. SA and ABA pre-treatments had less effect on APX activity earlier under heat stress. These results suggest that specific groups of potential signaling molecules may induce

  18. Development of a sensitive long pathlength absorbance photometer to quantify peroxides in aerosol particles (Peroxide-LOPAP)

    NASA Astrophysics Data System (ADS)

    Mertes, P.; Pfaffenberger, L.; Dommen, J.; Kalberer, M.; Baltensperger, U.

    2012-02-01

    A new off-line instrument to quantify peroxides in aerosol particles using iodometry in long pathlength absorption spectroscopy has been developed and is called peroxide long pathlength absorbance photometer (Peroxide-LOPAP). The new analytical setup features important technical innovations compared to hitherto published iodometric peroxide measurements. Firstly, the extraction, chemical conversion and measurement of the aerosol samples are performed in a closed oxygen-free (∼1 ppb) environment. Secondly, a 50-cm optical detection cell is used for an increased photometric sensitivity. The limit of detection was 0.1 μM peroxide in solution or 0.25 nmol m-3 with respect to an aerosol sample volume of 1000 l. The test reaction was done at a constant elevated temperature of 40 °C and the reaction time was 60 min. Calibration experiments showed that the test reaction with all reactive peroxides, i.e. hydrogen peroxide (H2O2), peracids and peroxides with vicinal carbonyl groups (e.g. lauroyl peroxide) goes to completion and their sensitivity (slope of calibration curve) varies by only ±5%. However, very stable peroxides have a lower sensitivity. For example tert-butyl hydroperoxide shows only 37% sensitivity compared to H2O2 after 1h. A kinetic study revealed that even after 5 h only 85% of this stable compound had reacted. The time trends of the peroxide content in secondary organic aerosol (SOA) from the ozonolysis and photo-oxidation of α-pinene in smog chamber experiments were measured. The highest amount of peroxides with 34% (assuming a MW of 300 g mol-1) was found in freshly generated SOA from α-pinene ozonolysis. Contents decreased with increasing NO levels in the photo-oxidation experiments. A decrease of the peroxide content was observed with aging of the aerosol indicating a decomposition of peroxides in the particles.

  19. Development of a sensitive long path absorption photometer to quantify peroxides in aerosol particles (Peroxide-LOPAP)

    NASA Astrophysics Data System (ADS)

    Mertes, P.; Pfaffenberger, L.; Dommen, J.; Kalberer, M.; Baltensperger, U.

    2012-10-01

    A new off-line instrument to quantify peroxides in aerosol particles using iodometry in long path absorption spectroscopy has been developed and is called peroxide long path absorption photometer (Peroxide-LOPAP). The new analytical setup features important technical innovations compared to hitherto published iodometric peroxide measurements. Firstly, the extraction, chemical conversion and measurement of the aerosol samples are performed in a closed oxygen-free (~ 1 ppb) environment. Secondly, a 50-cm optical detection cell is used for an increased photometric sensitivity. The limit of detection was 0.1 μM peroxide in solution or 0.25 nmol m-3 with respect to an aerosol sample volume of 1 m3. The test reaction was done at a constant elevated temperature of 40 °C and the reaction time was 60 min. Calibration experiments showed that the test reaction with all reactive peroxides, i.e. hydrogen peroxide (H2O2), peracids and peroxides with vicinal carbonyl groups (e.g. lauroyl peroxide) goes to completion and their sensitivity (slope of calibration curve) varies by only ±5%. However, very inert peroxides have a lower sensitivity. For example, tert-butyl hydroperoxide shows only 37% sensitivity compared to H2O2 after 1 h. A kinetic study revealed that even after 5 h only 85% of this inert compound had reacted. The time trends of the peroxide content in secondary organic aerosol (SOA) from the ozonolysis and photo-oxidation of α-pinene in smog chamber experiments were measured. The highest mass fraction of peroxides with 34% (assuming a molecular weight of 300 g mol-1) was found in freshly generated SOA from α-pinene ozonolysis. Mass fractions decreased with increasing NO levels in the photo-oxidation experiments. A decrease of the peroxide content was also observed with aging of the aerosol, indicating a decomposition of peroxides in the particles.

  20. Cumene peroxide and Fe(2+)-ascorbate-induced lipid peroxidation and effect of phosphoglucose isomerase.

    PubMed

    Agadjanyan, Z S; Dugin, S F; Dmitriev, L F

    2006-09-01

    Malondialdehyde (MDA) is one of cytotoxic aldehydes produced in cells as a result of lipid peroxidation and further MDA metabolism in cytoplasm is not known. In our experiments the liver fraction 10,000 g containing phosphoglucose isomerase and enzymes of the glyoxalase system was used and obtained experimental data shows that in this fraction there is an aggregate of reactions taking place both in membranes (lipid peroxidation) and outside membranes. MDA accumulation is relatively slow because MDA is a substrate of aldehyde isomerase (MDA <--> methylglyoxal). The well known enzyme phosphoglucose isomerase acts as an aldehyde isomerase (Michaelis constant for this enzyme Km = 133 +/- 8 microM). MDA conversion to methylglyoxal and further to neutral product D-lactate (with GSH as a cofactor) occurs in cytoplasm and D-lactate should be regarded as the end product of two different parametabolic reactions: lipid peroxidation or protein glycation.