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Sample records for acid hydrolysis

  1. Hemicellulose hydrolysis catalysed by solid acids

    P.D.. Carà; M. Pagliaro; A. Elmekawy; D.R. Brown; P. Verschuren; N.R. Shiju; G. Rothenberg

    2013-01-01

    Depolymerising hemicellulose into platform sugar molecules is a key step in developing the concept of an integrated biorefinery. This reaction is traditionally catalysed by either enzymes or homogeneous mineral acids. We compared various solid catalysts for hemicellulose hydrolysis, running reaction

  2. Mechanisms of lactone hydrolysis in acidic conditions.

    Gómez-Bombarelli, Rafael; Calle, Emilio; Casado, Julio

    2013-07-19

    The acid-catalyzed hydrolysis of linear esters and lactones was studied using a hybrid supermolecule-polarizable continuum model (PCM) approach including up to six water molecules. The compounds studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate, methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-butyrolactone, 2(5H)-furanone, and δ-valerolactone. The theoretical results are in good quantitative agreement with the experimental measurements reported in the literature and also in excellent qualitative agreement with long-held views regarding the nature of the hydrolysis mechanisms at molecular level. The present results help to understand the balance between the unimolecular (A(AC)1) and bimolecular (A(AC)2) reaction pathways. In contrast to the experimental setting, where one of the two branches is often occluded by the requirement of rather extreme experimental conditions, we have been able to estimate both contributions for all the compounds studied and found that a transition from A(AC)2 to A(AC)1 hydrolysis takes place as acidity increases. A parallel work addresses the neutral and base-catalyzed hydrolysis of lactones. PMID:23731203

  3. Microwave-assisted Weak Acid Hydrolysis of Proteins

    Miyeong Seo

    2012-06-01

    Full Text Available Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at 37 oC, 50 oC, and100 oC for 1 h. The most effective hydrolysis was observed at 100 oC. Hydrolysis products were investigated using matrixassistedlaser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini ofaspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60-min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at100 oC. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteinsand that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.

  4. ACID HYDROLYSIS OF HEMICELLULOSE FROM SUGARCANE BAGASSE

    A. PESSOA JR.

    1997-09-01

    Full Text Available Hydrolysis of the hemicellulosic fraction of sugarcane bagasse by sulphuric acid was performed in laboratory (25 mL and semi-pilot (25 L reactors under different conditions of temperature, time and acid concentration. On the laboratory scale, the three highest recovery yields were obtained at: 140ºC for 10 min with 100 mgacid/gdm (yield=73.4%; 140ºC for 20 min with 100 mgacid/gdm (yield=73.9% and 150ºC for 20 min with 70 mgacid/gdm (yield=71.8%. These conditions were also used for hydrolysis in a semi-pilot reactor, and the highest xylose recovery yield (83.3% was obtained at 140ºC for 20 min with 100 mgacid/gdm

  5. Hemicellulose hydrolysis catalysed by solid acids

    Carà, P.D..; Pagliaro, M.; Elmekawy, A.; Brown, D R; Verschuren, P.; Shiju, N.R.; Rothenberg, G.

    2013-01-01

    Depolymerising hemicellulose into platform sugar molecules is a key step in developing the concept of an integrated biorefinery. This reaction is traditionally catalysed by either enzymes or homogeneous mineral acids. We compared various solid catalysts for hemicellulose hydrolysis, running reactions in water, under neutral pH and relatively mild temperature and pressure (120 degrees C and 10 bar) conditions. Sulphonated resins are highly active, but they leach out sulphonic groups. Sulphonat...

  6. Acid-functionalized nanoparticles for biomass hydrolysis

    Pena Duque, Leidy Eugenia

    Cellulosic ethanol is a renewable source of energy. Lignocellulosic biomass is a complex material composed mainly of cellulose, hemicellulose, and lignin. Biomass pretreatment is a required step to make sugar polymers liable to hydrolysis. Mineral acids are commonly used for biomass pretreatment. Using acid catalysts that can be recovered and reused could make the process economically more attractive. The overall goal of this dissertation is the development of a recyclable nanocatalyst for the hydrolysis of biomass sugars. Cobalt iron oxide nanoparticles (CoFe2O4) were synthesized to provide a magnetic core that could be separated from reaction using a magnetic field and modified to carry acid functional groups. X-ray diffraction (XRD) confirmed the crystal structure was that of cobalt spinel ferrite. CoFe2O4 were covered with silica which served as linker for the acid functions. Silica-coated nanoparticles were functionalized with three different acid functions: perfluoropropyl-sulfonic acid, carboxylic acid, and propyl-sulfonic acid. Transmission electron microscope (TEM) images were analyzed to obtain particle size distributions of the nanoparticles. Total carbon, nitrogen, and sulfur were quantified using an elemental analyzer. Fourier transform infra-red spectra confirmed the presence of sulfonic and carboxylic acid functions and ion-exchange titrations accounted for the total amount of catalytic acid sites per nanoparticle mass. These nanoparticles were evaluated for their performance to hydrolyze the beta-1,4 glycosidic bond of the cellobiose molecule. Propyl-sulfonic (PS) and perfluoropropyl-sulfonic (PFS) acid functionalized nanoparticles catalyzed the hydrolysis of cellobiose significantly better than the control. PS and PFS were also evaluated for their capacity to solubilize wheat straw hemicelluloses and performed better than the control. Although PFS nanoparticles were stronger acid catalysts, the acid functions leached out of the nanoparticle during

  7. Hydrolysis of Polysaccharides with 77% Sulfuric Acid for Quantitative Saccharification

    UÇAR, Güneş; Balaban, Mualla

    2003-01-01

    Classical standard hydrolysis of polysaccharides with 72% sulfuric acid was modified in 2 manners. In order to avoid treatment in an autoclave at 120 °C under pressure, wood or pulp material was first swollen in cold 77% acid followed by hydrolysis steps in diluted acid solutions. Further, the neutralization of the hydrolyzate with dilute barium hydroxide was carried out in heated mother liquor ensuring a crystalline precipitate of barium sulfate. Digestion enables the separation of clear ali...

  8. Furfural production from fruit shells by acid-catalyzed hydrolysis

    Demirbas, A. [Selcuk Univ., Konya (Turkey). Dept. of Chemical Engineering

    2006-01-21

    Pentosans are hydrolyzed to pentoses by dilute mineral acid hydrolysis. The main source of pentosans is hemicelluloses. Furfural can be produced by the acid hydrolysis of pentosan from fruit shells such as hazelnut, sunflower, walnut, and almond of agricultural wastes. Further dehydration reactions of the pentoses yield furfural. The hydrolysis of each shell sample was carried out in dilute sulfuric acid (0.05 to 0.200 mol/l), at high temperature (450-525 K), and short reaction times (from 30 to 600 s). (author)

  9. Hydrolysis of isocyanic acid on SCR catalysts

    Elsener, M.; Kleemann, M.; Koebel, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Standard SCR catalysts possess high activity for the hydrolysis of HNCO and thus explain the suitability of urea as a selective reducing agent for NO{sub x}. At high space velocities HNCO-slip can get perceptible over the entire temperature range. This can be attributed to the fact that the temperature dependence is strong for the SCR reaction, but weak for the hydrolysis reaction. (author) 3 figs., 5 refs.

  10. Kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid

    Girisuta, B.; Janssen, L. P. B. M.; Heeres, H. J.

    2007-01-01

    A variety of interesting bulk chemicals is accessible by the acid-catalyzed hydrolysis of cellulose. An interesting example is levulinic acid, a versatile precursor for fuel additives, polymers, and resins. A detailed kinetic study on the acid-catalyzed hydrolysis of cellulose to levulinic acid is r

  11. Acid hydrolysis of Biomass lignocellulose Onopordum nervosum Boiss

    Hydrolysis of resistant cellulose of Onopordum nervosum Boiss (thistle) to reducing sugars in dilute sulfuric acid in glass ampoules and long residence times has been studied and kinetic parameters determined. The rate of hydrolysis is similar to that of the cellulose of Douglas fir, but comparatively the effect of the acid is more pronounced than temperature. From kinetic data it can be pre ducted the yield and since it can be obtained at least 45% of the potential glucose (48% as reducing sugars) at 190 degree centigree, 1,6% acid and 6,1 min. residence time, it indicates that the continuous acid hydrolysis of thistle may be a process of commercial interest. (Author) 18 refs

  12. OPTIMIZATION STUDY OF CITRUS WASTES SACCHARIFICATION BY DILUTE ACID HYDROLYSIS

    Farid Talebnia

    2008-02-01

    Full Text Available The effect of time, acid concentration, temperature and solid concentration on dilute-acid hydrolysis of orange peels was investigated. A central composite rotatable experimental design (CCRD was applied to study the individual effects of these hydrolysis factors and also their interdependence effects. The enzymatic hydrolysis of the peels by cellulase, β-glucosidase, and pectinase enzyme resulted in 72% dissolution of the peels, including 18.7% galacturonic acid and 53.3% of a total of glucose, fructose, galactose, and arabinose. Dilute-acid hydrolysis up to 210°C was not able to hydrolyze pectin to galacturonic acid. However, the sugar polymers were hydrolyzed at relatively low temperature. The optimum results were obtained at 116°C, 0.5% sulfuric acid concentration, 6% solid fraction, and 12.9 min retention time. Under these conditions, the total sugars obtained at 41.8 g/g dry peels and 2.6% of total hexose sugars were further degraded to hydroxymethylfurfural (HMF. No furfural was detected through these experiments from decomposition of pentoses.

  13. Simultaneous hydrolysis-esterification of wet microalgal lipid using acid.

    Takisawa, Kenji; Kanemoto, Kazuyo; Kartikawati, Muliasari; Kitamura, Yutaka

    2013-12-01

    This research demonstrated hydrolysis of wet microalgal lipid and esterification of free fatty acid (FFA) using acid in one-step process. The investigation of simultaneous hydrolysis-esterification (SHE) of wet microalgal lipid was conducted by using L27 orthogonal design and the effects of water content, volume of sulphuric acid, volume of methanol, temperature and time on SHE were examined. As a result, water content was found to be the most effective factor. The effects of various parameters on fatty acid methyl ester (FAME) content and equilibrium relation between FAME and FFA were also examined under water content 80%. Equimolar amounts of sulphuric acid and hydrochloric acid showed similar results. This method has great potential in terms of biodiesel production from microalgae since no organic solvents are used. PMID:24080318

  14. Acid hydrolysis of kallar grass (leptochloa fusca) for the production

    Acid hydrolysis of kallar grass (leptochloa fusca) was carried of with various concentrations of sulphuric acid, ortho phosphoric acid and hydrochloric acid to produce furfural. The study revealed that activity of various hydrolysing acids to produce furfural from kallar grass was of the following order H/sub 2/SO/sub 4/ > H/sub 3/PO/sub 4/ > HCl. Optimum yield (4.78%) of the produce was obtained when the material was digested with 19% H/sub 2/SO/sub 4/ for a period of 20 minutes. (author)

  15. Intramolecular Amide Hydrolysis in N-Methylmaleamic Acid Revisited

    2002-01-01

    The intramolecular amide hydrolysis of N-methylmaleamic acid have been revisited by use of density functional theory and inclusion of solvent effects. The results indicate that concerted reaction mechanism is favored over stepwise reaction mechanism. This is in agreement with the previous theoretical study. Sovlent effects have significant influence on the reaction barrier.

  16. Carbon-based strong solid acid for cornstarch hydrolysis

    Nata, Iryanti Fatyasari, E-mail: yanti_tkunlam@yahoo.com [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Irawan, Chairul; Mardina, Primata [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Lee, Cheng-Kang, E-mail: cklee@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Rd. Sec.4, Taipei 106, Taiwan (China)

    2015-10-15

    Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

  17. Enhancement of hydrolysis of Chlorella vulgaris by hydrochloric acid.

    Park, Charnho; Lee, Ja Hyun; Yang, Xiaoguang; Yoo, Hah Young; Lee, Ju Hun; Lee, Soo Kweon; Kim, Seung Wook

    2016-06-01

    Chlorella vulgaris is considered as one of the potential sources of biomass for bio-based products because it consists of large amounts of carbohydrates. In this study, hydrothermal acid hydrolysis with five different acids (hydrochloric acid, nitric acid, peracetic acid, phosphoric acid, and sulfuric acid) was carried out to produce fermentable sugars (glucose, galactose). The hydrothermal acid hydrolysis by hydrochloric acid showed the highest sugar production. C. vulgaris was hydrolyzed with various concentrations of hydrochloric acid [0.5-10 % (w/w)] and microalgal biomass [20-140 g/L (w/v)] at 121 °C for 20 min. Among the concentrations examined, 2 % hydrochloric acid with 100 g/L biomass yielded the highest conversion of carbohydrates (92.5 %) into reducing sugars. The hydrolysate thus produced from C. vulgaris was fermented using the yeast Brettanomyces custersii H1-603 and obtained bioethanol yield of 0.37 g/g of algal sugars. PMID:26899601

  18. Heteropoly acid catalyzed hydrolysis of glycogen to glucose

    Complete conversion of glycogen to glucose is achieved by using H3PW12O40·nH2O (HPW) and H4SiW12O40·nH2O (HSiW) as catalysts for the hydrolysis under optimized hydrothermal conditions (mass fraction of catalyst 2.4%, 373 K and 2 h reaction time). The reusability of the catalyst (HPW) was demonstrated. In addition to carrying out the glycogen hydrolysis in an autoclave, other novel methods such as microwave irradiation and sonication have also been investigated. At higher mass fraction of the heteropoly acids (10.5%), glycogen could be completely converted to glucose under microwave irradiation. Sonication of an aqueous solution of glycogen in the presence of HPW and HSiW also yielded glucose. Thus, heteropoly acids are efficient, environmentally friendly and reusable catalysts for the conversion of glycogen to glucose. - Highlights: • Hydrothermal, microwave and sonication based methods of hydrolysis. • Heteropoly acids are green catalysts for glycogen hydrolysis. • Glycogen from cyanobacteria is demonstrated as a potential feedstock for glucose

  19. Carbon-based strong solid acid for cornstarch hydrolysis

    Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

    2015-10-01

    Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

  20. Dilute Acid Hydrolysis of Cowpea Hulls: A Kinetic Study

    Chioma M. Onyelucheya

    2016-08-01

    Full Text Available In this study, dilute acid hydrolysis of cowpea hulls was carried out in two stages under the following conditions: pre-hydrolysis (4%v/v H2SO4, 121˚C, 30 minutes and hydrolysis ( at 10% and 15% v/v H2SO4,varied at different temperatures 150 oC, 160 oC, 170 oC and 180 oC for 2.5 hrs.. The substrate was characterized using both Fourier transform infrared spectroscopy and proximate analysis. The percentage lignocellulosic composition of the substrate was obtained for cellulose, hemicellulose and lignin as 34%, 14% and 4.7% respectively. Maximum glucose concentration of 8.09g was obtained using 10%v/v acid concentration at 170˚C after a reaction time of 90min. Saeman’s model gave a good fit for the experimental data. Activation energy for glucose formation using 10%v/v and 15%v/v H2SO4 was obtained as 38.28KJ and 82.204KJ respectively. From the results obtained it can be concluded that cowpea hulls can be converted to a useful product.

  1. Acid hydrolysis and carbohydrates characterization of coffee pulp

    Urbaneja, G. [Universidad de los Andes, Trujillo (Venezuela). Nucleo Universitario Rafael Rangel; Ferrer, J.; Paez, G. [Universidad del Zulia, Maracaibo (Venezuela). Facultad de Ingenieria; Arenas, L.; Colina, G. [Universidad del Zulia, Marcaibo (Venezuela). Facultad de Agronomia

    1996-09-01

    Hydrolysis of coffee pulp with diluted sulfuric acid was studied by keeping boiling temperature with reflux, a liquid to solid ratio of 10:1 and a particle size {<=} 1.00 mm. Coffee pulp was treated using several acid concentration (C) and retention times (t). The hydrolysates were analyzed for total sugars by phenol-sulfuric acid and HPLC (TSPA and TSHPLC), reducing sugar (RS) by DNS and individual sugars by HPLC. Data were analyzed by using the Statistical Analysis System (SAS). The average sugar yields were: TSHPLC between 12.87-20.31% and 14.02-19.01%; TSPA between 23.41-19.07% and 25.74-30.58%; RS between 10.24-19.07% and 9.66-17.80% for (C) y (t) respectively, expressed as wt% of dry coffee pulp. The general range of variations for individual sugars was: xylose from 0.08 to 3.23; arabinose from 0.23 to 11.26; fructose from 0.90 to 3.00 and glucose from 1.30 to 6.31, expressed in gl{sup -1}. The sucrose varied between 0.08 and 3.96 and maltose between 0.01 and 3.50, also expressed in gl{sup -1} of hydrolysate. The overall efficiency of hydrolysis was 64% for TSPA and 67% for RS. (Author)

  2. Enzymatic hydrolysis of sugarcane bagasse pretreated with acid or alkali

    Vivian Cristina Pietrobon

    2011-04-01

    Full Text Available The aim of this study was to evaluate the performance of enzymatic hydrolysis of acid or alkali pretreated sugarcane bagasse for the production of fermentable sugars. The first step consisted of selection of commercial enzymes presenting the highest cellulolytic activities. After selection of four enzymes: HPL, CL, P1 and P4, their performances were tested in the bagasse pretreated with acid and alkali. The sugar content of the hydrolysates was analyzed by anion exchange liquid chromatography. Data showed that the joint action of 0.5% acid pretreatment, 121ºC, 30 minutes and enzyme CL provides the best results, 67.25 g of hexose and 148.13g of pentose per kg of dry bagasse.

  3. Conversion of rice straw to sugars by dilute-acid hydrolysis

    Hydrolysis of rice straw by dilute sulfuric acid at high temperature and pressure was investigated in one and two stages. The hydrolyses were carried out in a 10-l reactor, where the hydrolysis retention time (3-10 min), pressure (10-35 bar) and acid concentration (0-1%) were examined. Optimization of first stage hydrolysis is desirable to achieve the highest yield of the sugars from hemicellulose and also as a pretreatment for enzymatic hydrolysis. The results show the ability of first stage hydrolysis to depolymerize xylan to xylose with a maximum yield of 80.8% at hydrolysis pressure of 15 bar, 10 min retention time and 0.5% acid concentration. However, the yield of glucose from glucan was relatively low in first stage hydrolysis at a maximum of 25.8%. The solid residuals were subjected to further dilute-acid hydrolysis in this study. This second-stage hydrolysis without addition of the acid could not increase the yield of glucose from glucan beyond 26.6%. On the other hand, the best results of the hydrolysis were achieved, when 0.5% sulfuric acid was added prior to each stage in two-stage hydrolysis. The best results of the second stage of the hydrolysis were achieved at the hydrolysis pressure and the retention time of 30 bar and 3 min in the second stage hydrolysis, where a total of 78.9% of xylan and 46.6% of glucan were converted to xylose and glucose, respectively in the two stages. Formation of furfural and HMF were functions of the hydrolysis pressure, acid concentration, and retention time, whereas the concentration of acetic acid was almost constant at pressure of higher than 10 bar and a total retention time of 10 min

  4. The Crystalline Changes of Starch from Rhizoma Dioscorea by Acid Hydrolysis

    Shu Jun WANG; Wen Yuan GAO; Jing Lin YU; Pei Gen XIAO

    2006-01-01

    The changes in crystalline properties of starch from Rhizoma Dioscorea by acid hydrolysis was characterized by X-Ray diffractometry (XRD). The results revealed that the crystalline type of Rhizoma Dioscorea starch changed from C-type to A-type after 16 days of the acid hydrolysis. This phenomenon was different from that of other starches subjected to the acid hydrolysis. The results revealed that the B-polymorphs of C-type starch constituted the amorphous regions while the crystalline areas were mainly composed of A-polymorphs. The degree of crystallinity of the acid-thinned starch increased gradually with the time of acid hydrolysis.

  5. Production of reducing sugar from oil palm empty fruit bunch (EFB) cellulose fibres via acid hydrolysis

    Siew Xian Chin; Chin Hua Chia; Sarani Zakaria

    2013-01-01

    Cellulosic fibre of oil palm empty fruit bunches (EFB) were used as a raw material for acid hydrolysis using mineral acids (H2SO4 and HCl) to produce reducing sugar at moderate temperature and atmospheric pressure. Experiments were carried out to investigate the effect of the hydrolysis parameters, including acid concentration, temperature, and reaction time, on the total reducing sugar (TRS) yield with the aid of response surface methodology (RSM). The preliminary hydrolysis studies of the E...

  6. Simulation of acid hydrolysis of lignocellulosic residues to fermentable sugars for bioethanol production

    Sidiras, Dimitris

    2012-12-01

    The dilute acid hydrolysis of fir sawdust with sulfuric acid was undertaken in a batch reactor system (autoclave). The experimental data and reaction kinetic analysis indicate that this is a potential process for cellulose and hemicelluloses hydrolysis, due to a rapid hydrolysis reaction for acid concentration 0.045 N at 160-180°C. It was found that significant sugar degradation occurred at these conditions. The optimum conditions gave a yield of 38% total fermentable sugars. The kinetics of dilute acid hydrolysis of cellulose and hemicelluloses (polysaccharides) were simulated using four pseudo-kinetic models. The reaction rate constants were calculated in each case.

  7. Hydrolysis of dilute acid-pretreated cellulose under mild hydrothermal conditions.

    Chimentão, R J; Lorente, E; Gispert-Guirado, F; Medina, F; López, F

    2014-10-13

    The hydrolysis of dilute acid-pretreated cellulose was investigated in a conventional oven and under microwave heating. Two acids--sulfuric and oxalic--were studied. For both hydrothermal conditions (oven and microwave) the resultant total organic carbon (TOC) values obtained by the hydrolysis of the cellulose pretreated with sulfuric acid were higher than those obtained by the hydrolysis of the cellulose pretreated with oxalic acid. However, the dicarboxylic acid exhibited higher hydrolytic efficiency towards glucose. The hydrolysis of cellulose was greatly promoted by microwave heating. The Rietveld method was applied to fit the X-ray patterns of the resultant cellulose after hydrolysis. Oxalic acid preferentially removed the amorphous region of the cellulose and left the crystalline region untouched. On the other hand, sulfuric acid treatment decreased the ordering of the cellulose by partially disrupting its crystalline structure. PMID:25037336

  8. Vitamin B2 content determination in liver paste by using acid and acid-enzyme hydrolysis

    Basić Zorica

    2007-01-01

    Full Text Available Background/Aim. Vitamin B2 is available in foodstuff in the form of coenzyme and in free form. For its content determination a few procedures should be performed (deliberation from a complex, extraction of free and deliberated form and detection, identification and quantification. There is a particular problem in determination of vitamin B2 in the meat products. For a determination of total vitamin B2 content in liver paste two preparation procedures are compared: acid and acid-enzymatic hydrolysis. The aim of this study thus, was to compare the effectiveness of these two different procedures for vitamin B2 content determination in liver paste. Methods. High pressure liquid chromatography (HPLC method with fluorescence detector, as specific and adequately sensitive for the foodstuff of a complex composition with a natural vitamin content, was used for determination of vitamin B2 in liver paste. Acid hydrolysis was performed with the application 0.1 M hydrochloric acid in a pressure cooker, and enzymatic hydrolysis was performed with the 10% takadiastase on 45 ºC within four hours. Ten samples of liver paste from the supply of the Serbian Army were examined. Separation was performed on the analytical column Nucleosil 50−5 C18 with mobile phase 450 ml CH3OH + 20 ml 5 mM CH3COONH4, and detection on the fluorescent detector with the variable wave length. Both methods were validated: examining a detection limit, quantification limit, specificity (because of a possible B2 vitamin interference with reagents, linearity of a peak area and standard concentration of B2 vitamin ratio in the range from 0.05 μg/ml to 2 μg/ml, precision for the 0.05 μg/ml concentration and recovery. Results. All the previously examined parameters validated both methods as specific, precise and reproductive, with a high recovery (98.5% for acid and 98.2% for acid - enzymatic hydrolysis, as well as linearity in a range that significantly superseded the expected content in

  9. Study on the Hydrolysis Kinetics of Xylan on Different Acid Catalysts

    In this study, we investigated kinetic model for the acid-catalyzed xylan hydrolysis at temperature 120-150 .deg. C. Also, we analyzed the kinetic parameters for xylose production and furfural decomposition. The hydrolysis of xylan and the degradation of xylose were promoted by high reaction temperature and acid concentration. The optimal hydrolysis condition for the highest reaction rate constants (k1) was different depending on the acid catalysts. Among sulfuric, oxalic and maleic acid, the xylan reaction rate constants (k1) to xylose had the highest value of 0.0241 min-1 when 100 mM sulfuric acid was used at 120 .deg. C. However, sulfuric acid induced more xylose degradation compared to oxalic and maleic acid hydrolysis. The activation energy for xylan degradation was the highest when sulfuric acid was used

  10. Study on the Hydrolysis Kinetics of Xylan on Different Acid Catalysts

    Na, Byeong-Il; Lee, Jae-Won [Chonnam National University, Gwangju (Korea, Republic of)

    2014-04-15

    In this study, we investigated kinetic model for the acid-catalyzed xylan hydrolysis at temperature 120-150 .deg. C. Also, we analyzed the kinetic parameters for xylose production and furfural decomposition. The hydrolysis of xylan and the degradation of xylose were promoted by high reaction temperature and acid concentration. The optimal hydrolysis condition for the highest reaction rate constants (k{sub 1}) was different depending on the acid catalysts. Among sulfuric, oxalic and maleic acid, the xylan reaction rate constants (k{sub 1}) to xylose had the highest value of 0.0241 min{sup -1} when 100 mM sulfuric acid was used at 120 .deg. C. However, sulfuric acid induced more xylose degradation compared to oxalic and maleic acid hydrolysis. The activation energy for xylan degradation was the highest when sulfuric acid was used.

  11. Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Sterol Glycosides from Foods Rich in Δ(7)-Sterols.

    Münger, Linda H; Jutzi, Sabrina; Lampi, Anna-Maija; Nyström, Laura

    2015-08-01

    In this study, we present the difference in sterol composition of extracted steryl glycosides (SG) hydrolyzed by either enzymatic or acid hydrolysis. SG were analyzed from foods belonging to the plant families Cucurbitaceae (melon and pumpkin seeds) and Amaranthaceae (amaranth and beetroot), both of which are dominated by Δ(7)-sterols. Released sterols were quantified by gas chromatography with a flame ionization detector (GC-FID) and identified using gas chromatography/mass spectrometry (GC-MS). All Δ(7)-sterols identified (Δ(7)-stigmastenyl, spinasteryl, Δ(7)-campesteryl, Δ(7)-avenasteryl, poriferasta-7,25-dienyl and poriferasta-7,22,25-trienyl glucoside) underwent isomerization under acidic conditions and high temperature. Sterols with an ethylidene or methylidene side chain were found to form multiple artifacts. The artifact sterols coeluted with residues of incompletely isomerized Δ(7)-sterols, or Δ(5)-sterols if present, and could be identified as Δ(8(14))-sterols on the basis of relative retention time, and their MS spectra as trimethylsilyl (TMS) and acetate derivatives. For instance, SG from melon were composed of 66% Δ(7)-stigmastenol when enzymatic hydrolysis was performed, whereas with acid hydrolysis only 8% of Δ(7)-stigmastenol was determined. The artifact of Δ(7)-stigmastenol coeluted with residual non-isomerized spinasterol, demonstrating the high risk of misinterpretation of compositional data obtained after acid hydrolysis. Therefore, the accurate composition of SG from foods containing sterols with a double bond at C-7 can only be obtained by enzymatic hydrolysis or by direct analysis of the intact SG. PMID:25757602

  12. Acid hydrolysis of the biomass of resistant cellulose of thistle ''Onopordum nervosum boiss''

    Hydrolysis of resistant cellulose of ''Onopordum nervosum boiss'' (thistle) to reduce sugar in diluted sulfuric acid in glass ampoules and long residence times have been studied and kinetic parameters determined. The rate of hydrolysis is similar to that of the cellulose of Douglas fir, but comparatively the effect of the acid is more pronounced than temperature. From kinetic data the yield can be predicted and since it can be obtained at least 45% of the potential glucose (48% as reducing sugars) at 190 deg C, 1.6% acid and 6.1 min. residence time, it indicates that the continuous acid hydrolysis of thistle may be a process of commercial interest. (author)

  13. Kinetics of Sawdust Hydrolysis with Dilute Hydrochloric Acid and Ferrous Chloride

    袁传敏; 颜涌捷; 任铮伟; 李庭琛; 曹建勤

    2004-01-01

    With dilute hydrochloric acid as catalyst and promoted by ferrous chloride, hydrolysis of waste sawdust to produce monosaccharides was conducted by using an one-step method in a batch-wise operation reactor. Based on the model of first order consecutive irreversible reactions, the kinetics equation incorporating the term of catalyst concentration was obtained that is suitable for describing the hydrolysis of sawdust. Activation energies were calculated for hydrolysis of sawdust and decomposition of monosaccharides.

  14. The influence of solid/liquid separation techniques on the sugar yield in two-step dilute acid hydrolysis of softwood followed by enzymatic hydrolysis

    Galbe Mats; Monavari Sanam; Zacchi Guido

    2009-01-01

    Abstract Background Two-step dilute acid hydrolysis of softwood, either as a stand-alone process or as pretreatment before enzymatic hydrolysis, is considered to result in higher sugar yields than one-step acid hydrolysis. However, this requires removal of the liquid between the two steps. In an industrial process, filtration and washing of the material between the two steps is difficult, as it should be performed at high pressure to reduce energy demand. Moreover, the application of pressure...

  15. Effect of an acid filler on hydrolysis and biodegradation of poly-lactic acid (PLA)

    Iozzino, Valentina; Speranza, Vito; Pantani, Roberto

    2015-12-01

    The use of biodegradable polymers is certainly an excellent strategy to solve many of the problems related to the disposal of the traditional polymers, whose accumulation in the environment is harmful and damaging. In order to optimize the use of biodegradable polymers, it is very important to understand and control the transformation processes, the structures and the morphologies resulting from the process conditions used to produce the articles and, not least, the biodegradation. The latter is strictly dependent on the just mentioned variables. The poly-lactic acid, PLA, is a biodegradable polymer. Many studies have been carried out on the degradation process of this polymer. In the course of this work we performed degradation tests on the PLA, with a specific D-isomer content, having amorphous structure, and in particular of biodegradation and hydrolysis. An acid chemical, fumaric acid, was added to PLA with the objective of controlling the rate of hydrolysis and of biodegradation. The hydrolysis process was followed, as function of time, by means of different techniques: pH variation, variation of weight of samples and variation of crystallinity degree and glass transition temperature using DSC analysis. The samples were also analyzed in terms of biodegradability by means of a homemade respirometer apparatus, in controlled composting conditions.

  16. Acid hydrolysis of cellulosic fibres: Comparison of bleached kraft pulp, dissolving pulps and cotton textile cellulose.

    Palme, Anna; Theliander, Hans; Brelid, Harald

    2016-01-20

    The behaviour of different cellulosic fibres during acid hydrolysis has been investigated and the levelling-off degree of polymerisation (LODP) has been determined. The study included a bleached kraft pulp (both never-dried and once-dried) and two dissolving pulps (once-dried). Additionally, cotton cellulose from new cotton sheets and sheets discarded after long-time use was studied. Experimental results from the investigation, together with results found in literature, imply that ultrastructural differences between different fibres affect their susceptibility towards acid hydrolysis. Drying of a bleached kraft pulp was found to enhance the rate of acid hydrolysis and also result in a decrease in LODP. This implies that the susceptibility of cellulosic fibres towards acid hydrolysis is affected by drying-induced stresses in the cellulose chains. In cotton cellulose, it was found that use and laundering gave a substantial loss in the degree of polymerisation (DP), but that the LODP was only marginally affected. PMID:26572472

  17. Comparison of dilute mineral and organic acid pretreatment for enzymatic hydrolysis of wheat straw

    Kootstra, A.M.J.; Beeftink, H.H.; Scott, E.L.; Sanders, J.P.M.

    2009-01-01

    The efficiencies of fumaric, maleic, and sulfuric acid in wheat straw pretreatment were compared. As a measure for pretreatment efficiency, enzymatic digestibility of the lignocellulose was determined. Monomeric glucose and xylose concentrations were measured after subsequent enzymatic hydrolysis, a

  18. Acid and enzymatic hydrolysis to recover reducing sugars from cassava bagasse: an economic study

    Woiciechowski Adenise Lorenci

    2002-01-01

    Full Text Available The objective of this work was to study the acid and enzymatic hydrolysis of cassava bagasse for the recovery of reducing sugars and to establish the operational costs. A statistical program "Statistica", based on the surface response was used to optimize the recovery of reducing sugars in both the processes. The process economics was determined considering the values of reducing sugars obtained at laboratory scale, and the operations costs of a cylindrical reactor of 1500 L, with flat walls at the top and bottom. The reactor was operated with 150 kg of cassava bagasse and 1350 kg of water. The yield of the acid hydrolysis was 62.4 g of reducing sugars from 100 g of cassava bagasse containing 66% starch. It represented 94.5% of reducing sugar recovery. The yield of the enzymatic hydrolysis was 77.1 g of reducing sugars from 120 g of cassava bagasse, which represented 97.3% of reducing sugars recovery. Concerning to the time, a batch of acid hydrolysis required 10 minutes, plus the time to heat and cool the reactor, and a batch of the enzymatic hydrolysis needed 25 hours and 20 minutes, plus the time to heat and to cool the reactor. Thus, the acid hydrolysis of 150 kg of cassava bagasse required US$ 34.27, and the enzymatic hydrolysis of the same amount of cassava bagasse required US$ 2470.99.

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

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

    2013-01-01

    The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature ((o)C), time (hr) and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables with P maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker's yeast (Sacchromyces cerveasiae). PMID:26417215

  20. Solid Acid-Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR-IR Spectroscopy

    Zakzeski, J.; Grisel, R.J.H.; Smit, A.T.; Weckhuysen, B.M.

    2012-01-01

    The solid acid-catalyzed hydrolysis of cellulose was studied under elevated temperatures and autogenous pressures using in situ ATR-IR spectroscopy. Standards of cellulose and pure reaction products, which include glucose, fructose, hydroxymethylfurfural (HMF), levulinic acid (LA), formic acid, and

  1. Kinetics of the hydrolysis of polysaccharide galacturonic acid and neutral sugars chains from flaxseed mucilage

    Happi Emaga, T.

    2012-01-01

    Full Text Available Different hydrolysis procedures of flaxseed polysaccharides (chemical and enzymatic were carried out with H2SO4, HCl and TFA at different acid concentrations (0.2, 1 and 2 M and temperatures (80 and 100°C. Enzymatic and combined chemical and enzymatic hydrolyses of polysaccharide from flaxseed mucilage were also studied. Acid hydrolysis conditions (2 M H2SO4, 4 h, 100°C are required to quantify total monosaccharide content of flaxseed mucilage. The enzymatic pathway (Pectinex™ Ultra SP limits sugar destruction during hydrolysis, but it is also insufficient for complete depolymerization. The combination of the two treatments, i.e. moderate chemical hydrolysis (0.2 M H2SO4, 80°C, 48 h combined with enzymatic hydrolysis is not more effective compared to chemical hydrolysis in drastic conditions (2 M H2SO4 at 100°C. The strong interaction between the neutral and acid fractions of flaxseed mucilage may hinder total release of sugar residues. Physical treatment prior to the hydrolysis could be necessary to achieve complete depolymerisation of flaxseed mucilage.

  2. Enhanced xylose recovery from oil palm empty fruit bunch by efficient acid hydrolysis.

    Tan, Hooi Teng; Dykes, Gary A; Wu, Ta Yeong; Siow, Lee Fong

    2013-08-01

    Oil palm empty fruit bunch (EFB) is abundantly available in Malaysia and it is a potential source of xylose for the production of high-value added products. This study aimed to optimize the hydrolysis of EFB using dilute sulfuric acid (H2SO4) and phosphoric acid (H3PO4) via response surface methodology for maximum xylose recovery. Hydrolysis was carried out in an autoclave. An optimum xylose yield of 91.2 % was obtained at 116 °C using 2.0 % (v/v) H2SO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. A lower optimum xylose yield of 24.0 % was observed for dilute H3PO4 hydrolysis at 116 °C using 2.4 % (v/v) H3PO4, a solid/liquid ratio of 1:5 and a hydrolysis time of 20 min. The optimized hydrolysis conditions suggested that EFB hydrolysis by H2SO4 resulted in a higher xylose yield at a lower acid concentration as compared to H3PO4. PMID:23709290

  3. Ultrasound-assisted dilute acid hydrolysis of tea processing waste for production of fermentable sugar.

    Germec, Mustafa; Tarhan, Kübra; Yatmaz, Ercan; Tetik, Nedim; Karhan, Mustafa; Demirci, Ali; Turhan, Irfan

    2016-03-01

    Lignocellulosic materials that are the most abundant plant biomass in the world have the potential to become sustainable sources of the produced value added products. Tea processing waste (TPW) is a good lignocellulosic source to produce the value added products from fermentable sugars (FSs). Therefore, the present study is undertaken to produce FSs by using ultrasound-assisted dilute acid (UADA) and dilute acid (DA) hydrolysis of TPW followed by enzymatic hydrolysis. UADA hydrolysis of TPW was optimized by response surface methodology (RSM) at maximum power (900 W) for 2 h. The optimum conditions were determined as 50°C, 1:6 (w/v) solid:liquid ratio, and 1% (w/v) DA concentration, which yielded 20.34 g/L FS concentration. Furthermore, its DA hydrolysis was also optimized by using RSM for comparison and the optimized conditions were found as 120°C, 1:8 solid:liquid ratio, and 1% acid concentration, which produced 25.3 g/L FS yield. Even though the produced sugars with UADA hydrolysis are slightly less, but it can provide significant cost saving due to the lower temperature requirement and less liquid consumption. Besides, enzymatic hydrolysis applied after pretreatments of TPW were very more economic than the conventional enzymatic hydrolysis in the literature due to shorter time requiring. In conclusion, ultrasound-assisted is a promising technology that can be successfully applied for hydrolysis of biomass and can be an alternative to the other hydrolysis procedures and also TPW can be considered as suitable carbon source for the production of value-added products like biofuels, organic acids, and polysaccharides. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:393-403, 2016. PMID:26749037

  4. Optimization of acid hydrolysis from the hemicellulosic fraction of Eucalyptus grandis residue using response surface methodology.

    Canettieri, Eliana Vieira; de Moraes Rocha, George Jackson; de Carvalho, João Andrade; de Almeida e Silva, João Batista

    2007-01-01

    Biotechnological conversion of biomass into fuels and chemicals requires hydrolysis of the polysaccharide fraction into monomeric sugars. Hydrolysis can be performed enzymatically and with dilute or concentrate mineral acids. The present study used dilute sulfuric acid as a catalyst for hydrolysis of Eucalyptus grandis residue. The purpose of this paper was to optimize the hydrolysis process in a 1.4 l pilot-scale reactor and investigate the effects of the acid concentration, temperature and residue/acid solution ratio on the hemicellulose removal and consequently on the production of sugars (xylose, glucose and arabinose) as well as on the formation of by-products (furfural, 5-hydroxymethylfurfural and acetic acid). This study was based on a model composition corresponding to a 2(3) orthogonal factorial design and employed the response surface methodology (RSM) to optimize the hydrolysis conditions, aiming to attain maximum xylose extraction from hemicellulose of residue. The considered optimum conditions were: H(2)SO(4) concentration of 0.65%, temperature of 157 degrees C and residue/acid solution ratio of 1/8.6 with a reaction time of 20 min. Under these conditions, 79.6% of the total xylose was removed and the hydrolysate contained 1.65 g/l glucose, 13.65 g/l xylose, 1.55 g/l arabinose, 3.10 g/l acetic acid, 1.23 g/l furfural and 0.20 g/l 5-hydroxymethylfurfural. PMID:16473004

  5. Extraction of protein and amino acids from deoiled rice bran by subcritical water hydrolysis.

    Sereewatthanawut, Issara; Prapintip, Surawit; Watchiraruji, Katemanee; Goto, Motonobu; Sasaki, Mitsuru; Shotipruk, Artiwan

    2008-02-01

    This study investigated the production of value-added protein and amino acids from deoiled rice bran by hydrolysis in subcritical water (SW) in the temperature range between 100 and 220 degrees C for 0-30 min. The results suggested that SW could effectively be used to hydrolyze deoiled rice bran to produce useful protein and amino acids. The amount of protein and amino acids produced are higher than those obtained by conventional alkali hydrolysis. The yields generally increased with increased temperature and hydrolysis time. However, thermal degradation of the product was observed when hydrolysis was carried out at higher temperature for extended period of time. The highest yield of protein and amino acids were 219 +/- 26 and 8.0 +/- 1.6 mg/g of dry bran, and were obtained at 200 degrees C at hydrolysis time of 30 min. Moreover, the product obtained at 200 degrees C after 30 min of hydrolysis exhibited high antioxidant activity and was shown to be suitable for use as culture medium for yeast growth. PMID:17320384

  6. Hydrolysis of acid and alkali presoaked lignocellulosic biomass exposed to electron beam irradiation.

    Karthika, K; Arun, A B; Melo, J S; Mittal, K C; Kumar, Mukesh; Rekha, P D

    2013-02-01

    In this study, synergetic effect of mild acid and alkali with electron beam irradiation (EBI) on the enzymatic hydrolysis of a selected grass biomass was assessed. Biomass samples prepared by soaking with 1% H2SO4, or 1% NaOH, were exposed to 75 and 150 kGy of EBI. Water presoaked biomass was used as control. Hydrolysis of pretreated samples was carried out using cellulase (15 FPU/g biomass) for 120 h. Structural changes were studied by FTIR and XRD analyses. Reducing sugar and glucose yields from enzymatic hydrolysis were significantly higher in acid and alkali presoaked EBI exposed samples. Theoretical glucose yield showed 40% increase from control in alkali presoaked EBI exposed (150 kGy) samples. Removal of hemicellulose, decreased crystallinity and structural changes were major factors for the combined treatment effect favoring the hydrolysis. PMID:23298772

  7. Proto pectin degradation of raw material by the acid hydrolysis

    The article presents results of hydrolysis proto pectin apples, an orange and a basket of sunflower depending on ph a solution. The reaction products are divided into three fractions conditionally named as micro gel, pectin substances and oligosaccharide. It was shown that the high-quality pectin extracted from orange, but high percentage of carboxylic group in the sunflower pectin allow it to by used as a drug delivery materials

  8. Radiation pretreatments for optimizing the sugar yield in the acid hydrolysis of waste cellulose

    Cellulosic wastes are now recognized as an underutilized renewable resource for both materials and energy recovery rather than a solid waste disposal problem. Acid hydrolysis offers a potentially attractive route for upgrading the value of cellulosic wastes by converting them to glucose. The glucose can then be used as an alternate feedstock to petrochemicals for fuels, intermediates and the synthesis of single cell protein. A key step in this developing technology is a cost effective cellulose waste pretreatment for optimizing the sugar yield. Various experimental approaches for achieving this objective are described. A combination waste cellulose pretreatment comprising the hydropulping of an electron beam irradiated cellulose waste feedstock followed by a short time dilute sulfuric acid hydrolysis has been found to be particularly effective. Data are given on the employment of various organic acids in place of sulfuric acid for the hydrolysis reaction. The power requirement and additional cost for the electron beam pretreatment are also discussed. (Auth.)

  9. Cellulose whiskers from sisal fibers: a study about the variable of extraction by acid hydrolysis

    The incorporation of cellulosic nanostructures in polymeric matrices has been studied due to their properties of biodegradation, and expected higher mechanical performance than the traditional composites. In this work, cellulose nanofibers were obtained from sisal bleached with reagents without chlorine, where it was used an acid mixture, with acetic acid and nitric acid, and after the bleached fibers were submitted to acid hydrolysis. The influence of the temperature and time of hydrolysis on the morphology and dimensions, crystallinity and thermal stability were analyzed by scanning transmission electronic microscopy (TEM), x-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. The hydrolysis condition of 60 deg C and 15 minutes showed to be the most effective condition to obtain whiskers from sisal fibers, resulting in nanostructures with higher crystallinity and thermal. (author)

  10. Comparative hydrolysis study of acetylsalicylic acid and copper - acetylsalicylate by rp-hplc method

    The hydrolysis of acetylsalicylic acid (ASA) and copper (II)-acetylsalicylate (CAS) was investigated by using a validated RP-HPLC method. Acetylsalicylic acid was hydrolyzed to (SA), where as CAS was hydrolyzed to ASA, SA, copper salicylate (CS), copper acetate and acetic acid. Comparison of hydrolysis was carried out by monitoring the concentration of SA, one of common hydrolysis product. The hydrolysis study was done in phosphate buffer solution in pH range from 3-11. The study was carried out at constant temperature to evaluate the effect of pH on both drugs. It was found that the hydrolysis rate of both drugs was same at pH value ranging from 3-11 as calculated from the Kapp and K values. However, there is a slight difference in the degradation of ASA and CAS as revealed from F-test. Results have indicated that CAS first hydrolyzes to acetylsalicylic acid which further hydrolyzes to SA, therefore availability of acetylsalicylic acid is increased. (author)

  11. Experimental and kinetic modelling studies on the acid-catalysed hydrolysis of the water hyacinth plant to levulinic acid

    Girisuta, B.; Danon, B.; Manurung, R.; Janssen, L. P. B. M.; Heeres, H. J.

    2008-01-01

    A comprehensive experimental and modelling study on the acid-catalysed hydrolysis of the water hyacinth plant (Eichhornia crassipes) to optimise the yield of levulinic acid (LA) is reported (T = 150-175 degrees C, C-H2SO4 - 0.1-1 M, water hyacinth intake = 1-5 wt%). At high acid concentrations (> 0.5 M), LA was the major organic acid whereas at low acid concentrations (

  12. Effect of Varying Acid Hydrolysis Condition in Gracilaria Sp. Fermentation Using Sasad

    Mansuit, H.; Samsuri, M. D. C.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.; Mansa, R.

    2015-04-01

    Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.

  13. Evaluation of hyper thermal acid hydrolysis of Kappaphycus alvarezii for enhanced bioethanol production.

    Ra, Chae Hun; Nguyen, Trung Hau; Jeong, Gwi-Taek; Kim, Sung-Koo

    2016-06-01

    Hyper thermal (HT) acid hydrolysis of Kappaphycus alvarezii, a red seaweed, was optimized to 12% (w/v) seaweed slurry content, 180mM H2SO4 at 140°C for 5min. The maximum monosaccharide concentration of 38.3g/L and 66.7% conversion from total fermentable monosaccharides of 57.6g/L with 120gdw/L K. alvarezii slurry were obtained from HT acid hydrolysis and enzymatic saccharification. HT acid hydrolysis at a severity factor of 0.78 efficiently converted the carbohydrates of seaweed to monosaccharides and produced a low concentration of inhibitory compounds. The levels of ethanol production by separate hydrolysis and fermentation with non-adapted and adapted Kluyveromyces marxianus to high concentration of galactose were 6.1g/L with ethanol yield (YEtOH) of 0.19 at 84h and 16.0g/L with YEtOH of 0.42 at 72h, respectively. Development of the HT acid hydrolysis process and adapted yeast could enhance the overall ethanol fermentation yields of K. alvarezii seaweed. PMID:26950757

  14. The Optimum Conditions for Production of Soya Peptone by Acidic Hydrolysis of Soya Proteins

    Sundus H. Ahammed

    2009-01-01

    Full Text Available This study was carried out to obtain the optimum conditions necessary for the process of soya protein hydrolysis by using hydrochloric acid (as a chemical catalyst instead of the papain enzyme (as a biological catalyst, for the production of soya peptone. These conditions are implemented to test the effect of the variables of the process of hydrolysis on the nature and quality of the product. The production of soya peptone was studied for their importance in the process of preparing and producing the culture media used in medical and microbiological laboratories. The process of production of soya peptone includes four main stages:•Preparing the defatted soya flour, firstly.•The soya protein hydrolysis, secondly. •Purifying the product, thirdly , and then, •Drying the product, finally. By following the procedure of the present study, the optimum conditions for the process of soya proteins hydrolysis have been reached in present study are:•Optimum concentration for the hydrochloric acid solution is 1N.•Optimum hydrolysis process temperature ranged between 50-53C. •Optimum period of hydrolysis time ranged between 17.189-19.97 hr. The productivity of soya peptone was 38.071%, by following the procedure and the optimum production conditions of the present study.

  15. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system

  16. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-10-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site`s Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  17. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-01-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  18. Fatty acid specificity of hormone-sensitive lipase. Implication in the selective hydrolysis of triacylglycerols.

    Raclot, T; Holm, C; Langin, D

    2001-12-01

    The selective mobilization of fatty acids from white fat cells depends on their molecular structure, in particular the degree of unsaturation. The present study was designed to examine if the release of fatty acids by hormone-sensitive lipase (HSL) in vitro i) is influenced by the amount of unsaturation, ii) depends on the temperature, and iii) could explain the selective pattern of fatty acid mobilization and notably the preferential mobilization of certain highly unsaturated fatty acids. Recombinant rat and human HSL were incubated with a lipid emulsion. The hydrolysis of 35 individual fatty acids, ranging in chain length from 12 to 24 carbon atoms and in unsaturation from 0 to 6 double bonds was measured. Fatty acid composition of in vitro released NEFA was compared with that of fat cell triacylglycerols (TAG), the ratio % NEFA/% TAG being defined as the relative hydrolysis. The relative hydrolysis of individual fatty acids differed widely, ranging from 0.44 (24:1n-9) to 1.49 (18:1n-7) with rat HSL, and from 0.38 (24:1n-9) to 1.67 (18:1n-7) with human HSL. No major difference was observed between rat and human HSL. The relative release was dependent on the number of double bonds according to chain length. The amount of fatty acid released by recombinant rat HSL was decreased but remained robust at 4 degrees C compared with 37 degrees C, and the relative hydrolysis of some individual fatty acids was affected. The relative hydrolysis of fatty acids moderately, weakly, and highly mobilized by adipose tissue in vivo was similar and close to unity in vitro. We conclude that i) the release of fatty acids by HSL is only slightly affected by their degree of unsaturation, ii) the ability of HSL to efficiently and selectively release fatty acids at low temperature could reflect a cold adaptability for poikilotherms or hibernators when endogenous lipids are needed, and iii) the selectivity of fatty acid hydrolysis by HSL does not fully account for the selective pattern of

  19. Kinetics of the hydrolysis of polysaccharide galacturonic acid and neutral sugars chains from flaxseed mucilage

    Happi Emaga, T.; Rabetafika, N.; Blecker, CS.; Paquot, M.

    2012-01-01

    Different hydrolysis procedures of flaxseed polysaccharides (chemical and enzymatic) were carried out with H2SO4, HCl and TFA at different acid concentrations (0.2, 1 and 2 M) and temperatures (80 and 100°C). Enzymatic and combined chemical and enzymatic hydrolyses of polysaccharide from flaxseed mucilage were also studied. Acid hydrolysis conditions (2 M H2SO4, 4 h, 100°C) are required to quantify total monosaccharide content of flaxseed mucilage. The enzymatic pathway (Pectinex™ Ultra SP) l...

  20. Influence of acid precursors on physicochemical properties of nanosized titania synthesized by thermal-hydrolysis method

    The influence of nature and concentration of acid species on surface morphology and physicochemical properties of titania particles synthesized by direct thermal hydrolysis of titanium tetrachloride was investigated. The acids used were hydrochloric acid, nitric acid, sulfuric acid, and perchloric acid with a concentration of 3 M. Thermal hydrolysis of titanium tetrachloride in hydrochloric acid and perchloric acid with molar ratios of [H+]/[Ti4+] = 0.5, 1.0, 1.5, and 2.0, respectively, was used to study the effect of acid concentration. The synthesized materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and thermogravimetric analysis. Characterization of the samples by X-ray diffraction studies revealed the influence of acid species on the phase transformation of titania. Samples prepared by hydrochloric acid, nitric acid, and perchloric acid formed rutile phase with rhombus primary particles, while sulfuric acid resulted in anatase phase with flake-shaped primary particles. Transmission electron microscopy and dynamic light scattering results confirmed the nanosized titania particles and the agglomeration of primary particles to form secondary particles in spherical shape. The particle size of titania prepared using perchloric acid was smaller than those prepared with other acid sources. A direct correlation between [H+]/[Ti4+] ratio and particle size of titania was observed

  1. Humic Acid-Like and Fulvic Acid-Like Inhibition on the Hydrolysis of Cellulose and Tributyrin

    Fernandes, T.V.; Lier, van J.B.; Zeeman, Grietje

    2015-01-01

    Enzymatic hydrolysis of complex wastes is a critical step for efficient biogas production in anaerobic digesters. Inhibition of this hydrolytic step was studied by addition of humic acid-like (HAL) and fulvic acid-like (FAL) substances, extracted from maize silage and fresh cow manure, to batch t

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

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

    2013-01-01

    The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature (oC), time (hr) and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables wit...

  3. Production of reducing sugar from oil palm empty fruit bunch (EFB cellulose fibres via acid hydrolysis

    Siew Xian Chin

    2013-02-01

    Full Text Available Cellulosic fibre of oil palm empty fruit bunches (EFB were used as a raw material for acid hydrolysis using mineral acids (H2SO4 and HCl to produce reducing sugar at moderate temperature and atmospheric pressure. Experiments were carried out to investigate the effect of the hydrolysis parameters, including acid concentration, temperature, and reaction time, on the total reducing sugar (TRS yield with the aid of response surface methodology (RSM. The preliminary hydrolysis studies of the EFB fibres showed that the presence of lignin in the fibres significantly affected the TRS yield. The maximum predicted TRS yield using H2SO4 was 30.61% under optimal conditions: acid concentration of 5 N, temperature of 139.65 oC, and reaction time of 4.16 h. For the hydrolysis using HCl, the maximum predicted TRS yield is 39.81% under optimal conditions: acid concentration of 4.63 N, temperature of 133.7 oC, reaction time of 2.05 h.

  4. Experimental study and product analysis of lignocellulosic biomass hydrolysis under extremely low acids

    Shurong WANG; Xinshu ZHUANG; Zhongyang LUO; Kefa CEN

    2008-01-01

    Using our self-designed facility for lignocellulo-sic biomass hydrolysis under extremely low acid, and under the optimal reaction conditions of hemicellulose and cel-lulose determined by xylan and quantitative filter paper as the model, two-step dilute acid hydrolysis was carried out in detail on pine, fast-growing poplar and maize straw. The corresponding conversion ratio is 41.78%, 57.84% and 53.44% and the total reducing sugar conversion ratio is 39.28%, 42.83% and 23.82% respectively. Simultaneously, sugar component analysis of the products was performed by high performance liquid chromatography (HPLC) and monosaccharide and oligosaccharide content were com-pared. Finally, poplar hydrolysis residues were analyzed by proximate and ultimate analysis.

  5. Acid hydrolysis of cellulose as the entry point into biorefinery schemes.

    Rinaldi, Roberto; Schüth, Ferdi

    2009-01-01

    Cellulose is a major source of glucose because it is readily available, renewable, and does not compete with the food supply. Hydrolysis of cellulose is experiencing a new research and development cycle in which this reaction is carried out over solid catalysts and coupled to other reactions for increased efficiency. Cellulose is typically not soluble in conventional solvents and very resistant to chemical and biological transformations. This Review focuses on aspects related to the hydrolysis of cellulose as this process is a significant entry point into the biorefinery scheme based on carbohydrates for the production of biofuels and biochemicals. Structural features of cellulose, conventional acid-catalyzed reactions, and the use of solid acid catalysts for hydrolysis are discussed. The longterm success of the biorefinery concept depends on the development of energetically efficient processes to convert cellulose directly or indirectly into biofuels and chemicals. PMID:19950346

  6. Preparation of Slowly Digestible Starch by Citric Acid-hydrolysis with Autoclaving

    Hansong Yu

    2015-03-01

    Full Text Available Aim of study is to produce Slowly Digestible Starch (SDS by a combination of citric acid-hydrolysis and autoclaving from raw corn starch. The effects of citric acid concentration, acid hydrolysis time, temperature and refrigeration and retro gradation time on the formation of SDS were investigated. The optimal process conditions optimized by Box-Benhnken’s central composite design and response surface analysis was as follows: concentration of citric acid is 0.08 M, acid hydrolyzed at 116°C for 14.5 min, and then stored at 0°C for 72 h. Under these optimal conditions, the content of SDS peaked at 19.38%.

  7. Monitoring the Hydrolysis of Olive Oil Catalyzed by Lipase via Acid Value Detection

    2007-01-01

    Hydrolysis of olive oil catalyzed by Candida lipolytica lipase was investigated. The relative concentration of the components in the product was determined by using high performance liquid chromatography(HPLC). Furthermore, a novel rapid method to detect the hydrolytic process of olive oil was developed based on the relationship between the acid value and the relative concentration of the different components.

  8. Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural from the waste liquid of acid hydrolysis NCC.

    Sun, Yonghui; Liu, Pengtao; Liu, Zhong

    2016-05-20

    The principal goal of this work was to reuse the carbohydrates and recycle sulfuric acid in the waste liquid of acid hydrolysis nanocrystalline cellulose (NCC). Therefore, in this work, the optimizations of further hydrolysis of waste liquid of acid hydrolysis NCC and catalytic conversion of L4 to 5-hydroxymethylfurfural (5-HMF) were studied. Sulfuric acid was separated by spiral wound diffusion dialysis (SWDD). The results revealed that cellulose can be hydrolyze to glucose absolutely under the condition of temperature 35 °C, 3 h, and sulfuric acid's concentration 62 wt%. And 78.3% sulfuric acid was recovered by SWDD. The yield of 5-HMF was highest in aqueous solution under the optimal condition was as follows, temperature 160 °C, 3 h, and sulfuric acid's concentration 12 wt%. Then the effect of biphasic solvent systems catalytic conversion and inorganic salt as additives were still examined. The results showed that both of them contributed to prepare 5-HMF. The yield and selectivity of 5-HMF was up to 21.0% and 31.4%, respectively. PMID:26917388

  9. Starch conversion of ganyong (Canna edulis Ker. to bioethanol using acid hydrolysis and fermentation

    LILY SURAYYA EKA PUTRI

    2008-04-01

    Full Text Available Starch of ganyong is one of the sources of ethanol which is able to be produced by acid hydrolysis and fermentation process. It had high concentration of carbohydrate that is 80%, so it could produce glucose highly within acid hydrolysis process. The result showed that the optimal amount of reducing sugar had been produced by nitrate acid 7% (dextrose equivalent, DE = 28.4. Nevertheless, type and concentration of acid had no significantly correlation to reducing sugar yielded. The total amount of glucose had correlation to amount of ethanol, in fermentation process. The optimal amount of ethanol was yielded from 4.81% of glucose and it produced about 4.84% ethanol. The more amount of glucose was yielded the more ethanol was produced. Controlling pH every 12 hours did not affected to production of ethanol significantly.

  10. Changes of the Anthocyanins and Antioxidant properties of Concord Grape (Vitis labrusca Pomace After Acid Hydrolysis

    Mustafa Bener

    2016-05-01

    Full Text Available Grape pomace contains high levels of valuable antioxidants such as anthocyanins and phenolic compounds that help prevent chronic diseases such as cardiovascular problems and cancers. In this study, Concord grape pomace was soaked in acidic solutions at different time intervals and pHs in a water bath at 80 oC. Five kinds of anthocyanins were released and identified in the pomace after acid hydrolysis. The releasing rate of anthocyanins and antioxidant activities of the acid hydrolyzed pomace extracts were determined by multitest systems. Different antioxidant assays including total antioxidant capacity (TAC, total phenolic content (TPC and free radical scavenging activity (RSA were used to evaluate the antioxidant properties of the acid hydrolyzed pomace extracts. The change in antioxidant capacity of the pomace extracts during hydrolysis was correlated with total phenolic content and free radical scavenging activity but had little relationship with anthocyanin contents.

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

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

    2010-03-01

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

  12. Weak acid hydrolysis of wood CTH. Final report; Svagsyrahydrolys av trae CTH. Slutrapport

    Linner, J.; Lundquist, K.; Ohlsson, Brita; Simonson, R. [Chalmers Univ. of Technology, Goeteborg (Sweden). Forest Products and Chemical Engineering

    1998-08-01

    Spruce wood meal was extracted with dichloromethane and used for production of holocellulose by standard delignification with sodium chlorite. The holocellulose as well as wood meal were used as substrate on hydrolysis with 0.1 or 0.5 M sulfuric acid at a substrate concentration of 5%. The hydrolysis trials were carried out in teflon containers that were rapidly heated to the reaction temperature (100 - 170 deg C) by means of microwaves. Reaction times of up to 4 hrs were used. The results showed that 80% of the polysaccharides in spruce wood meal and spruce holocellulose can be hydrolyzed to soluble products within 30 min under relatively mild conditions (160-170 deg C, 0.5 M sulfuric acid). The hydrolysates contained relatively small amounts of hydroximethylfurfural and its degradation product levulinic acid. Formed xylose was rapidly converted to furfural which in its turn was rapidly further reacted to condensation products. A maximum yield of hexose amounting to about 30 g/100 g substrate was obtained after about 15 min. This amount corresponds to about one third of the available hexoses in the holocellulose. Compared to the hemicellulose, the cellulose and especially the crystalline part is difficult to hydrolyze and the hemicellulose originating monosaccharides formed at an early stage seem to be destroyed to a large extent on prolonged hydrolysis. A two-step reaction at mild conditions should therefore be examined. Residues from the wood hydrolysis experiments were examined by IR spectroscopy. The spectra clearly showed that lignin accumulated in the residues. Several of the hydrolysis residues were dark-coloured (almost black). The strongly coloured constituents originate primarily from the carbohydrates. Dark-coloured precipitates were also obtained in hydrolysis experiments with carbohydrates. The IR spectra of these precipitates exhibited strong bands in the carbonyl region. Chloroform extracts of wood hydrolysates consisted mainly of conversion

  13. Hydrolysis optimization and characterization study of preparing fatty acids from Jatropha curcas seed oil

    Salimon Jumat; Abdullah Bashar; Salih Nadia

    2011-01-01

    Abstract Background Fatty acids (FAs) are important as raw materials for the biotechnology industry. Existing methods of FAs production are based on chemical methods. In this study potassium hydroxide (KOH)-catalyzed reactions were utilized to hydrolysis Jatropha curcas seed oil. Results The parameters effect of ethanolic KOH concentration, reaction temperature, and reaction time to free fatty acid (FFA%) were investigated using D-Optimal Design. Characterization of the product has been studi...

  14. Xylitol from rice husks by acid hydrolysis and Candida yeast fermentation

    Magale K. D. Rambo; Daiane B. Bevilaqua; Carla G. B. Brenner; Ayrton F. Martins; Débora N. Mario; Sydney H. Alves; Carlos A. Mallmann

    2013-01-01

    An investigation was conducted into the production of xylose by acid hydrolysis of rice husks and its subsequent bioconversion to xylitol. The parameters were optimised using the response surface methodology. The fermentation stage took place with the aid of the yeast species Candida guilliermondii and Candida tropicalis. An evaluation of the influence of several biomass pre-treatments was also performed. The effects of the acid concentration and hydrolysate pH on xylitol global yield were al...

  15. Hydrolysis of Straw in Ionic Liquids with Acid as Catalyst under Microwave Irradiation

    Yuanjing Zhang; Gang Wei; Guangyi Yu; Ning Qiao

    2015-01-01

    With ionic liquids as solvents and corn straw as raw material, different processes of lignocellulose pretreatment with acid as catalyst were studied under conventional heating/microwave irradiation and the reducing sugar was measured. The results indicated that acid can accelerate hydrolysis reaction of corn straw into reducing sugar with ionic liquids as solvent, and microwave irradiation was more efficient in pretreatment of corn straw than conventional heating. The influences of different ...

  16. Acid Pre hydrolysis of the Lignocellulose biomass from thistle Onopordum nervosum Boiss

    The acid pre hydrolysis of the lignocellulose biomass from thistle O. nervosum has been conducted to determine the conditions for maximum yield of pentoses with minimum yield of hexoses. Variables studied were acid concentration (H2SO4, 1 , 3, 4 and 5%) , temperature (1000 and 120 degree centigree) time, solid to liquid ratio and degree of fineness of thistle (1 to 65 mesh). (Author) 15 refs

  17. Acid Hydrolysis of Bromazepam Catalyzed by Micelles, Reverse Micelles, and Microemulsions

    Ferdousi Begum

    2015-01-01

    Full Text Available Kinetics of the acid hydrolysis of bromazepam (Bz has been investigated in micelles, reverse micelles, and microemulcions of cetyltrimethylammonium bromide (CTAB by spectrophotometric method. The rate of the acid hydrolysis of Bz was found to be enhanced both below and above the critical micelle concentration (CMC of CTAB in aqueous solution. The pseudo-first-order rate constant (k′ shows an initial decrease for both low and high H+ concentrations. With further increase in [CTAB], at low [H+], the k′ attains an almost constant value, while, at high [H+], the k′ passes through a maximum and then decreases. The kinetic data for catalysis by micelles of CTAB was interpreted with the pseudophase ion exchange (PIE model. In CTAB/cyclohexane/1-butanol/water microemulsions, as the water to surfactant ratio (wo increases, the physicochemical properties and droplet sizes of microemulsions significantly change and distinct changes in reaction environment can be marked. The rate of the hydrolysis reaction exhibits excellent correlation with the physicochemical properties and droplet sizes of the microemulsions and reverse micelles of CTAB. At [H+] = 0.001 M, in reverse micelles and microemulsions of CTAB, the k′ of the acid hydrolysis of Bz decreases sharply followed by a slight increase with increasing wo.

  18. Production of agaro- and carra-oligosaccharides by partial acid hydrolysis of galactans

    Diogo R. B. Ducatti

    2011-04-01

    Full Text Available Agaro- and carra-oligosaccharides were produced by partial acid hydrolysis of commercial agarose and kappa-carrageenan. Di- and tetrasaccharides were purified by gel filtration chromatography and characterized by NMR (1D and 2D spectroscopy and ESIMS. The following oligosaccharides were obtained: agarobiose, agarotetraose, kappa-carrabiose and kappa-carratetraose. Agarobiose and agarotetraose were used as standards to develop a high performance size exclusion chromatography (HPSEC method which was utilized to study the hydrolysis rate of agarose and oligosaccharide production. Six hours of hydrolysis (0.1 M TFA, 65 ºC produced mainly di- and tetrasaccharides. The methodology for oligosaccharide production and evaluation developed in the present work shows good potential for the production of bioactive oligosaccharides.

  19. Effect of gamma Irradiation on the acidic hydrolysis of free-hemi cellulose thistle

    The effect of gamma-irradiation on the subsequent acidic hydrolysis of free-hemi cellulose Onopordum Nervosum Boiss thistle Ls determined. Its shown the influence of gamma-irradiation on the yield of sugar obtained flora the batch wise hydrol isis of the call ulose (1% H2SO4 and 180 degree centigree at increasing doses. At all irradiation levels studied, the rate of hydrolysis of thistle samples was higher than the rate of hydrolysis of the cellulose from paper treated similarly. The maximum over-all yield of sugar in the irradiated lignocellulose material was about 66o at 100 MRad, less than two times the yield obtainable from the control. The corresponding yield from papel was 53%, 2'3 times that of the control. Irradiation under 1% H2SO4 doesn't enhance the yield anyway. (Author) 21 refs

  20. Production and effect of aldonic acids during enzymatic hydrolysis of lignocellulose at high dry matter content

    Cannella, David; Hsieh, Chia-Wen; Felby, Claus;

    2012-01-01

    Abstract Background: The recent discovery of accessory proteins that boost cellulose hydrolysis has increased the economical and technical efficiency of processing cellulose to bioethanol. Oxidative enzymes (e.g. GH61) present in new commercial enzyme preparations have shown to increase cellulose...... conversion yields. When using pure cellulose substrates it has been determined that both oxidized and unoxidized cellodextrin products are formed. We report the effect of oxidative activity in a commercial enzyme mix (Cellic CTec2) upon overall hydrolysis, formation of oxidized products and impact on ß...... hydrolysis of pretreated wheat straw at 30% WIS. Up to 4% of released glucose was oxidized into gluconic acid using Cellic CTec2, whereas no oxidized products were detected when using an earlier cellulase preparation Celluclast/Novozym188. However, the cellulose conversion yield was 25% lower using...

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

    Uju; Goto, Masahiro; Kamiya, Noriho

    2016-08-01

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

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

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

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

    Saidi, Anis Syuhada Mohd; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Padzil, Farah Nadia Mohammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-09-25

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

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

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

    2015-09-01

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

  5. Optimization of wastewater microalgae saccharification using dilute acid hydrolysis for acetone, butanol, and ethanol fermentation

    Castro, Yessica; Ellis, Joshua T.; Miller, Charles D.; Sims, Ronald C.

    2015-02-01

    Exploring and developing sustainable and efficient technologies for biofuel production are crucial for averting global consequences associated with fuel shortages and climate change. Optimization of sugar liberation from wastewater algae through acid hydrolysis was determined for subsequent fermentation to acetone, butanol, and ethanol (ABE) by Clostridium saccharoperbutylacetonicum N1-4. Acid concentration, retention time, and temperature were evaluated to determine optimal hydrolysis conditions by assessing the sugar and ABE yield as well as the associated costs. Sulfuric acid concentrations ranging from 0-1.5 M, retention times of 40-120 min, and temperatures from 23°C- 90°C were combined to form a full factorial experiment. Acid hydrolysis pretreatment of 10% dried wastewater microalgae using 1.0 M sulfuric acid for 120 min at 80-90°C was found to be the optimal parameters, with a sugar yield of 166.1 g for kg of dry algae, concentrations of 5.23 g/L of total ABE, and 3.74 g/L of butanol at a rate of USD $12.83 per kg of butanol.

  6. Conformational Footprint in Hydrolysis-Induced Nanofibrillation and Crystallization of Poly(lactic acid).

    Xu, Huan; Yang, Xi; Xie, Lan; Hakkarainen, Minna

    2016-03-14

    The origin of hydrolysis-induced nanofibrillation and crystallization, at the molecular level, was revealed by mapping the conformational ordering during long-term hydrolytic degradation of initially amorphous poly(lactic acid) (PLA), a representative model for degradable aliphatic polyesters generally displaying strong interplay between crystallization and hydrolytic erosion. The conformational regularization of chain segments was essentially the main driving force for the morphological evolution of PLA during hydrolytic degradation. For hydrolysis at 37 °C, no significant structural variations were observed due to the immobilization of "frozen" PLA chains. In contrast, conformational ordering in PLA was immediately triggered during hydrolysis at 60 °C and was responsible for the transition from random coils to disordered trans and, further, to quasi-crystalline nanospheres. On the surfaces, the head-by-head absorption and joining of neighboring nanospheres led to nanofibrillar assemblies following a "gluttonous snake"-like manner. The length and density of nanofibers formed were in close relation to the hydrolytic evolution, both of which showed a direct rise in the initial 60 days and then a gradual decline. In the interior, presumably the high surface energy of the nanospheres allowed for the preferential anchoring and packing of conformationally ordered chains into lamellae. In accordance with the well-established hypothesis, the amorphous regions were attacked prior to the erosion of crystalline entities, causing a rapid increase of crystallinity during the initial 30 days, followed by a gradual fall until 90 days. In addition to adequate illustration of hydrolysis-induced variations of crystallinity, our proposed model elucidates the formation of spherulitic nuclei featuring an extremely wide distribution of diameters ranging from several nanometers to over 5 μm, as well as the inferior resistance to hydrolysis observed for the primary nuclei. Our work

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

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

    2015-12-01

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

  8. Comparison of cell wall polysaccharide hydrolysis by a dilute acid/enzymatic saccharification process and rumen microorganisms

    Evaluation of biomass crops for breeding or pricing purposes requires an assay that predicts performance of biomass in the bioenergy conversion process. Cell wall polysaccharide hydrolysis by dilute sulfuric acid pretreatment at 121 degrees C followed by cellulase hydrolysis for 72 h (CONV) and in v...

  9. Synthesis of 18F-FDG using improved single-pot acid hydrolysis process

    In order to explore an optimum condition to increase the synthesis yield of 2-18F-2-deoxy-β-D-glucose (18F-FDG) by using improved single-pot acid hydrolysis Chemistry Process Control Unit (CPCU), various production conditions such as the reaction temperature, the time of acid hydrolysis and others were tested. The results showed that the determinant factor which affects the synthesis yield was the quantities of water present in reaction media. The total 18F-FDG synthesis time could be minimized by effective dehydration step and regulating the amount of hydrogen chloride. The synthesis yield could be increased by improving the production conditions of 18F-FDG. (authors)

  10. Nanocellulose prepared by acid hydrolysis of isolated cellulose from sugarcane bagasse

    Wulandari, W. T.; Rochliadi, A.; Arcana, I. M.

    2016-02-01

    Cellulose in nanometer range or called by nano-cellulose has attracted much attention from researchers because of its unique properties. Nanocellulose can be obtained by acid hydrolysis of cellulose. The cellulose used in this study was isolated from sugarcane bagasse, and then it was hydrolyzed by 50% sulfuric acid at 40 °C for 10 minutes. Nanocellulose has been characterized by Transmission Electron Microscope (TEM), Particle Size Analyzer (PSA), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD). Analysis of FTIR showed that there were not a new bond which formed during the hydrolysis process. Based on the TEM analysis, nano-cellulose has a spherical morphology with an average diameter of 111 nm and a maximum distribution of 95.9 nm determined by PSA. The XRD analysis showed that the crystallinity degree of nano-cellulose was higher than cellulose in the amount of 76.01%.

  11. Concentrated Sulfuric Acid Hydrolysis of Hardwood Aspen and Softwood Pine for Bioethanol Production

    Janga, Kando Khalifa

    2011-01-01

    Bioethanol production from lignocellulosic biomass has been targeted as an alternative solution to the existing dependence on fossil fuels in the transportation sector. However, the recalcitrant nature of lignocelluloses has been a challenge to the hydrolytic processes and hence commercialization.This study has investigated the feasibility of the concentrated sulfuric acid hydrolysis (CSAH) process for bioethanol production from wood-based lignocelluloses. This is because the process enjoys h...

  12. Uniform particles formed by hydrolysis of acid mine drainage with urea

    Šubrt, Jan; Michalková, E.; Boháček, Jaroslav; Lukáč, Jozef; Gánovská, Z.; Máša, B.

    2011-01-01

    Roč. 106, 1-2 (2011), s. 12-18. ISSN 0304-386X R&D Projects: GA MŠk LC523; GA MŠk(CZ) MEB0810136 Institutional research plan: CEZ:AV0Z40320502 Keywords : acid mine drainage * urea hydrolysis * morphology * particles * surface area Subject RIV: CA - Inorganic Chemistry Impact factor: 2.027, year: 2011

  13. Acid and enzymatic hydrolysis to recover reducing sugars from cassava bagasse: an economic study

    Woiciechowski Adenise Lorenci; Nitsche Saul; Pandey Ashok; Soccol Carlos Ricardo

    2002-01-01

    The objective of this work was to study the acid and enzymatic hydrolysis of cassava bagasse for the recovery of reducing sugars and to establish the operational costs. A statistical program "Statistica", based on the surface response was used to optimize the recovery of reducing sugars in both the processes. The process economics was determined considering the values of reducing sugars obtained at laboratory scale, and the operations costs of a cylindrical reactor of 1500 L, with flat walls ...

  14. Conversion of cellulosic feedstocks to ethanol and other chemicals using TVA's dilute sulfuric acid hydrolysis process

    The Tennessee Valley Authority (TVA) has been involved in the conversion of cellulosic feedstocks to ethanol and other products for over 10 years. Laboratory- and bench-scale research has been conducted to develop a two-stage, dilute sulfuric acid hydrolysis process. The process, based on work previously conducted at the Forest Products Laboratory, Madison, Wisconsin, uses high temperatures and pressures and short retention times to convert the hemicellulose and cellulose in biomass to fermentable sugars. Using hardwoods as the primary feedstock, evaluations of the process have resulted in sugar yields equivalent to 60 gallons of ethanol per ton of feedstock. Based on the results of bench-scale work, a two-ton-per-day pilot plant has been constructed and operated to further develop the process. Hydrolysis yields from the pilot-scale facility have been comparable to those achieved in the laboratory. Preliminary estimates have been prepared to determine capital and production costs for a 10-million-gallon-per-year ethanol-from-hardwoods facility. The effect of coproducts such as furfural, acetic acid, and carbon dioxide on production costs was also examined. This paper presents the results of bench- and pilot-scale research along with preliminary economics of TVA's dilute sulfuric acid hydrolysis process

  15. Xylitol from rice husks by acid hydrolysis and Candida yeast fermentation

    Magale K. D. Rambo

    2013-01-01

    Full Text Available An investigation was conducted into the production of xylose by acid hydrolysis of rice husks and its subsequent bioconversion to xylitol. The parameters were optimised using the response surface methodology. The fermentation stage took place with the aid of the yeast species Candida guilliermondii and Candida tropicalis. An evaluation of the influence of several biomass pre-treatments was also performed. The effects of the acid concentration and hydrolysate pH on xylitol global yield were also assessed, and the highest yield of xylitol was 64.0% (w/w. The main products, xylose and xylitol, were identified and quantified by means of liquid chromatography.

  16. Determination of Amino Acids in Panax notoginseng by Microwave Hydrolysis and Derivatization Coupled with Capillary Zone Electrophoresis Detection

    LI Xiao-tian; ZHAO Ya-jing; JIANG Cheng-fei; ZHANG Han-qi; YU Ai-min

    2013-01-01

    The microwave hydrolysis and derivatization coupled with capillary electrophoresis detection were developed for the separation and determination of the amino acids in Panax notoginseng.The experimental conditions for the microwave hydrolysis and derivatization were examined and optimized.Several parameters of capillary electrophoresis,such as pH value of background electrolyte,borate concentration and applied voltage were optimized.Under the selected conditions,11 amino acids were completely separated.The real sample was analyzed and the results were satisfactory.Compared with that of conventional heat hydrolysis and derivatization,the analytical time of this method was significantly shortened.

  17. Improved enzymatic hydrolysis of wheat straw by combined use of gamma ray and dilute acid for bioethanol production

    Hyun Hong, Sung; Taek Lee, Jae; Lee, Sungbeom; Gon Wi, Seung; Ju Cho, Eun; Singh, Sudhir; Sik Lee, Seung; Yeoup Chung, Byung

    2014-01-01

    Pretreating wheat straw with a combination of dilute acid and gamma irradiation was performed in an attempt to enhance the enzymatic hydrolysis for bioethanol production. The glucose yield was significantly affected by combined pretreatment (3% sulfuric acid-gamma irradiation), compared with untreated wheat straw and individual pretreatment. The increasing enzymatic hydrolysis after combined pretreatment is resulting from decrease in crystallinity of cellulose, loss of hemicelluloses, and removal or modification of lignin. Therefore, combined pretreatment is one of the most effective methods for enhancing the enzymatic hydrolysis of wheat straw biomass.

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

    F Xu; Y Shi; X Wu

    2011-12-31

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

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

    Fatmawati, Akbarningrum; Agustriyanto, Rudy

    2015-12-01

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

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

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

    2015-02-01

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

  1. Phosphine and thiophene cyclopalladated complexes: hydrolysis reactions in strong acidic media.

    García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Navarro, Ana M; Peñacoba, Indalecio A; Leal, José M

    2010-12-01

    The mechanisms for the hydrolysis of organopalladium complexes [Pd(CNN)R]BF(4) (R=P(OPh)(3), PPh(3), and SC(4)H(8)) were investigated at 25 °C by using UV/Vis absorbance measurements in 10 % v/v ethanol/water mixtures containing different sulphuric acid concentrations in the 1.3-11.7 M range. In all cases, a biphasic behavior was observed with rate constants k(1obs), which corresponds to the initial step of the hydrolysis reaction, and k(2obs), where k(1obs)>k(2obs). The plots of k(1obs) and k(2obs) versus sulfuric acid concentration suggest a change in the reaction mechanism. The change with respect to the k(1obs) value corresponds to 35 %, 2 %, and 99 % of the protonated complexes for R=PPh(3), P(OPh)(3), and SC(4)H(8), respectively. Regarding k(2obs), the change occurred in all cases at about 6.5 M H(2)SO(4) and matched up with the results reported for the hydrolysis of the 2-acetylpyridinephenylhydrazone (CNN) ligand. By using the excess acidity method, the mechanisms were elucidated by carefully looking at the variation of k(i),(obs) (i=1,2) versus cH+. The rate-determining constants, k(0,A-1), k(0,A-2), and k(0,A-SE2) were evaluated in all cases. The R=P(OPh)(3) complex was most reactive due to its π-acid character, which favors the rupture of the trans nitrogen-palladium bond in the A-2 mechanism and also that of the pyridine nitrogen-palladium bond in the A-1 mechanism. The organometallic bond exerts no effect on the relative basicity of the complexes, which are strongly reliant on the substituent. PMID:21125574

  2. Heteropoly Acid/Nitrogen Functionalized Onion-like Carbon Hybrid Catalyst for Ester Hydrolysis Reactions.

    Liu, Wei; Qi, Wei; Guo, Xiaoling; Su, Dangsheng

    2016-02-18

    A novel heteropoly acid (HPA)/nitrogen functionalized onion-like carbon (NOLC) hybrid catalyst was synthesized through supramolecular (electrostatic and hydrogen bond) interactions between the two components. The chemical structure and acid strength of the HPA/NOLC hybrid have been fully characterized by thermogravimetric analysis, IR spectroscopy, X-ray photoelectron spectroscopy, NH3 temperature-programmed desorption and acid-base titration measurements. The proposed method for the fabrication of the HPA/NOLC hybrid catalyst is a universal strategy for different types of HPAs to meet various requirements of acidic or redox catalysis. The hydrophobic environment of NOLC effectively prevents the deactivation of HPA in an aqueous system, and the combination of uniformly dispersed HPA clusters and the synergistic effect between NOLC and HPA significantly promotes its activity in ester hydrolysis reactions, which is higher than that of bare PWA as homogeneous catalyst. The kinetics of the hydrolysis reactions indicate that the aggregation status of the catalyst particles has great influence on the apparent activity. PMID:26606266

  3. Acid-based hydrolysis processes for ethanol from lignocellulosic materials: A review

    Keikhosro Karimi

    2007-01-01

    Full Text Available Bioethanol is nowadays one of the main actors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses can be expected to be major feedstocks for ethanol production in the future. Two processes are being developed in parallel for conversion of lignocelluloses to ethanol, “acid-based” and “enzyme-based” processes. The current article is dedicated to review of progress in the “acid-based-hydrolysis” process. This process was used industrially in the 1940s, during wartime, but was not economically competitive afterward. However, intensive research and development on its technology during the last three decades, in addition to the expanding ethanol market, may revive the process in large scale once again. In this paper the ethanol market, the composition of lignocellulosic materials, concentrated- and dilute-acid pretreatment and hydrolysis, plug-flow, percolation, counter-current and shrinking-bed hydrolysis reactors, fermentation of hexoses and pentoses, effects of fermentation inhibitors, downstream processing, wastewater treatment, analytical methods used, and the current commercial status of the acid-based ethanol processes are reviewed.

  4. Acid hydrolysis of sisal cellulose: studies aiming at nano fibers and bio ethanol preparation

    The hydrolysis of cellulose can result in nanofibers and also is an important stage in the bioethanol production process. In order to evaluate the influence of acid (sulfuric) concentration, temperature, and native cellulose (sisal) pretreatment on cellulose hydrolysis, the acid concentration was varied between 5% and 30% (v/v) in the temperature range from 60 to 100 deg C using native and alkali-treated (mercerized) sisal cellulose. The following techniques were used to evaluate the residual (non-hydrolysed) cellulose characteristics: viscometry, average degree of polymerization (DP), X-ray diffraction, crystallinity index, and Scanning Electron Microscopy. The sugar cane liquor was analyzed in terms of sugar composition, using High Performance Liquid Chromatography (HPLC). The results showed that increasing the concentration of sulfuric acid and temperature afforded residual cellulose with lower molecular weight and, up to specific acid concentrations, higher crystallinity indexes, when compared to the original cellulose values, and increased the glucose (the bioethanol precursor ) production of the liquor, which was favored for mercerized cellulose. (author)

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

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

    2010-12-01

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

  6. Overall process considerations for using dilute acid cellulose hydrolysis technology to produce ethanol from biomass

    Recent advances in reactors, designed for the dilute acid thermochemical treatment of biomass, have resulted in the development of process alternatives in which both cellulose and hemicellulose are hydrolyzed to soluble sugars in high yields. The optimal extent of cellulose hydrolysis will depend on both the performance and economics of the thermochemical treatment operation, and on subsequent unit operations in the bioethanol production process. Examples of subsequent unit operation interactions include the extent to which cellulase enzymes are used to hydrolyze any remaining cellulose, kinetics and conditions of a largely soluble mixed sugar cofermentation, and the extent to which removal of compounds that inhabit fermenting microorganisms is required. In addition, a number of process operation and economic considerations affect the ultimate economic viability of this type of biomass hydrolysis process. These considerations include reactor design issues to accommodate the kinetic parameters of the various hydrolysis and sugar degradation reactions, liquid volume requirements to achieve acceptable sugar yields, sugar concentrations that result from such a process and their impact on subsequent fermentation volumes and ethanol recovery operations, potential co-product opportunities that result from solubilized lignin, and process steam requirements. Several potential whole-process configurations are presented and key process and economic issues for each are discussed. (author)

  7. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave

    Su, Tong-Chao; Fang, Zhen; Zhang, Fan; Luo, Jia; Li, Xing-Kang

    2015-12-01

    In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g-1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg-1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% under the best conditions at 190 °C for 3.5 h. It was cycled for at least seven times with high catalyst recovery rate (92.8%), acid density (0.63 mmol g-1) and magnetism (Ms = 12.9 Am2 kg-1), as well as high TRS yield (20.1%) from the hydrolysis of ball-milled cellulose. The catalyst was further successfully tested for the hydrolysis of tropical biomass with high TRS and glucose yields of 79.8% and 58.3% for bagasse, 47.2% and 35.6% for Jatropha hulls, as well as 54.4% and 35.8% for Plukenetia hulls.

  8. Nitrification of archaeal ammonia oxidizers in acid soils is supported by hydrolysis of urea

    Lu, Lu; Han, Wenyan; Zhang, Jinbo; Wu, Yucheng; Wang, Baozhan; Lin, Xiangui; Zhu, Jianguo; Cai, Zucong; Jia, Zhongjun

    2012-01-01

    The hydrolysis of urea as a source of ammonia has been proposed as a mechanism for the nitrification of ammonia-oxidizing bacteria (AOB) in acidic soil. The growth of Nitrososphaera viennensis on urea suggests that the ureolysis of ammonia-oxidizing archaea (AOA) might occur in natural environments. In this study, 15N isotope tracing indicates that ammonia oxidation occurred upon the addition of urea at a concentration similar to the in situ ammonium content of tea orchard soil (pH 3.75) and ...

  9. Two New Dammarane Glycosides from the Acid Hydrolysis Product of Panax Notoginseng

    2001-01-01

    Two new dammarane glycosides named notoginsenoside T1 and T2 were isolated from the mild acid hydrolysis products of the root saponins of Panax notoginseng. On the basis of spectroscopic evidences, their structures were elucidated to be 6-O-?-D-glucopyranosyl-24(25)-epoxy-3?,6?,12?,23ξ-tetrahydroxydammar-20(22)(E)-ene 1 and 6-O-?-D-glucopyranosyl-24(25)-epoxy-23ξ-methoxyl-3?,6?,12?-trihydroxydamm-ar-20(22)(E)-ene 2, respectively.

  10. Isolation of pectin from pumpkin (Cucurbita moschata, L.) by acid hydrolysis

    Pumpkin (Cucurbita moschata, L.) constitutes an excellent source of carotenoids, precursors of vitamin A. Besides, it also that constitutes also a great natural source of low-cost pectin. Pectin is a heterogeneous complex polysaccharide found in the primary cell wall of most plants and its effect on health is receiving increasing interest from the scientific community. In this work, high-methoxy pectin was obtained from pumpkin (Cucurbita moschata, L.) through the acid hydrolysis methodology. The pectin obtained was characterized by FTIR, NMR 1H, GPC and rheology. (author)

  11. Catalytic hydrolysis of CFC-12 over solid acid Ti(SO4)2

    2000-01-01

    The catalytic hydrolysis of dichlorodifluoromethane (CFC-12) was investigated over solid acid Ti(SO4)2. The catalytic activity decreased with the calcination temperature. When space velocity was 6 l h-1 g-cat-1, the CFC-12 conversion at 310oC over Ti(SO4)2 calcined at 350oC remained about 98.5% during 360 h on stream, and the selectivity to by-products remained zero. The findings enlarged the scope of traditional catalyst systems for the CFCs decomposition.

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

    Jin Sun

    2010-11-01

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

  13. INFLUENCE OF ACID CONCENTRATION, TEMPERATURE, AND TIME ON THE CONCENTRATED SULFURIC ACID HYDROLYSIS OF PINEWOOD AND ASPENWOOD: A STATISTICAL APPROACH

    Kando K. Janga

    2011-11-01

    Full Text Available The effects on sugar yields of acid concentration, temperature, and time in the first (decrystallization stage of a two-stage concentrated sulfuric acid hydrolysis of softwood (Scots pine and hardwood (aspen were investigated. The study focused on the multi-variable effects of the decrystallization stage and applied a statistical modeling with Central Composite Face (CCF design of experiment to systematically study and simulate the effect of decrystallization reaction conditions on hydrolysis products and degradation products. The models were statistically significant and showed that for both aspen and pine, the reaction temperature and acid concentration were the most influential variables on monosaccharides and total sugar yields compared to the reaction time. The interaction between temperature and acid concentration was the most important for both species. The sugar degradation products were much influenced by the decrystallization temperature on both aspen and pine. The models were validated by a test-set and showed a good agreement between the experimental and predicted values. The optimum predicted total sugar yields were 56 g / 100 g d.w for aspen (74% theoretical and 64 g / 100 g d.w for pine (91% theoretical.

  14. EFFECT OF INHIBITORS ON ENZYMATIC HYDROLYSIS AND SIMULTANEOUS SACCHARIFICATION FERMENTATION FOR LACTIC ACID PRODUCTION FROM STEAM EXPLOSION PRETREATED LESPEDEZA STALKS

    Yue Feng,

    2012-06-01

    Full Text Available The effects on both cellulose conversion rate and lactic acid yield were studied by adding inhibitors, including formic acid, acetic acid, furfural, and vanillin into the hydrolysate of steam-pretreated Lespedeza stalks. The results suggest that formic acid has a significant influence on the enzyme activity and poisoned bacterial cells, resulting in the reduction of cellulose conversion rate and lactic acid yield by 21% and 16.4%, respectively. Acetic acid showed a strong inhibition on simultaneous saccharification fermentation (SSF process, but little effect on enzymatic hydrolysis. Hydrolysis and SSF were less affected by furfural and vanillin compared with weak acids. The lactic acid yield of Lespedeza stalks rinsed with water increased from 64.0% to 89.4%, and the time to reach the maximum concentration was shortened from 96 hours to 48 hours when compared with the unwashed materials.

  15. Quantitative solid state NMR analysis of residues from acid hydrolysis of loblolly pine wood.

    Sievers, Carsten; Marzialetti, Teresita; Hoskins, Travis J C; Valenzuela Olarte, Mariefel B; Agrawal, Pradeep K; Jones, Christopher W

    2009-10-01

    The composition of solid residues from hydrolysis reactions of loblolly pine wood with dilute mineral acids is analyzed by (13)C Cross Polarization Magic Angle Spinning (CP MAS) NMR spectroscopy. Using this method, the carbohydrate and lignin fractions are quantified in less than 3h as compared to over a day using wet chemical methods. In addition to the quantitative information, (13)C CP MAS NMR spectroscopy provides information on the formation of additional extractives and pseudo lignin from the carbohydrates. Being a non-destructive technique, NMR spectroscopy provides unambiguous evidence of the presence of side reactions and products, which is a clear advantage over the wet chemical analytical methods. Quantitative results from NMR spectroscopy and proximate analysis are compared for the residues from hydrolysis of loblolly pine wood under 13 different conditions; samples were treated either at 150 degrees C or 200 degrees C in the presence of various acids (HCl, H(2)SO(4), H(3)PO(4), HNO(3) and TFA) or water. The lignin content determined by both methods differed on averaged by 2.9 wt% resulting in a standard deviation of 3.5 wt%. It is shown that solid degradation products are formed from saccharide precursors under harsh reaction conditions. These degradation reactions limit the total possible yield of monosaccharides from any subsequent reaction. PMID:19477123

  16. Hydrolysis optimization and characterization study of preparing fatty acids from Jatropha curcas seed oil

    Salimon Jumat

    2011-11-01

    Full Text Available Abstract Background Fatty acids (FAs are important as raw materials for the biotechnology industry. Existing methods of FAs production are based on chemical methods. In this study potassium hydroxide (KOH-catalyzed reactions were utilized to hydrolysis Jatropha curcas seed oil. Results The parameters effect of ethanolic KOH concentration, reaction temperature, and reaction time to free fatty acid (FFA% were investigated using D-Optimal Design. Characterization of the product has been studied using Fourier transforms infrared spectroscopy (FTIR, gas chromatography (GC and high performance liquid chromatography (HPLC. The optimum conditions for maximum FFA% were achieved at 1.75M of ethanolic KOH concentration, 65°C of reaction temperature and 2.0 h of reaction time. Conclusions This study showed that ethanolic KOH concentration was significant variable for J. curcas seed oil hydrolysis. In a 18-point experimental design, FFA% of hydrolyzed J. curcas seed oil can be raised from 1.89% to 102.2%, which proved by FTIR and HPLC.

  17. Improvement Enzymatic Hydrolysis of Wheat Straw for Bioethanol Production by Combined Treatment of Radiation and Acid

    Hong, Sung Hyun; Lee, Seung Sik; Bai, Hyoung Woo; Chung, Byung Yeoup [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2012-05-15

    The cost of ethanol production from starch and sucrose for use as a vehicle fuel is ultimately high. Consequently, it has been suggested that the large-scale use of ethanol as a fuel will require the utilization of cellulosic feedstock. Lignocellulosic biomass has the potential to serve as a low cost and renewable feedstock for bioconversion into fermentable sugars, which can be further utilized for biofuel production. It is estimated that there is over one billion tons of biomass available for conversion into biofuels on a renewable basis to displace a substantial portion of the fossil fuels currently consumed within the transportation sector. Among different pretreatment methods such as biological, physical, chemical, and physic-chemical pretreatments, chemical pretreatment using dilute acid as catalyst, which has been extensively evaluated for treating a variety of lignocellulosic feedstocks, is reported as one of the leading pretreatment technologies. Ionizing radiation can easily penetrate lignocellulosic structure and undoubtedly produce free radicals useful in modification of lignin structure as well as breakdown cellulose crystal regions. Phenoxy radicals appeared to be important radical intermediates that ultimately transformed into o-quinonoid structures in lignin. Therefore, ionizing radiation such as gamma ray and electron beam can be a great alternative. In this study, the effect of ionizing irradiation of wheat straw prior to dilute sulfuric acid treatment is investigated. The combined pretreatment for wheat straw was performed to evaluate the efficiency of enzymatic hydrolysis and compared with that of the effect of enzymatic hydrolysis by individual pretreatment

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

    Sørensen, Annette; Teller, Philip Johan; Hilstrøm, Troels;

    2008-01-01

    Miscanthus is a high yielding bioenergy crop. In this study we used acid presoaking, wet explosion, and enzymatic hydrolysis to evaluate the combination of the different pre-treatment methods for bioethanol production with Miscanthus. Acid presoaking is primarily carried out in order to remove...

  19. Effect of acid hydrolysis and fungal biotreatment on agro-industrial wastes for obtainment of free sugars for bioethanol production

    T.S. El-Tayeb

    2012-12-01

    Full Text Available This study was designed to evaluate selected chemical and microbiological treatments for the conversion of certain local agro-industrial wastes (rice straw, corn stalks, sawdust, sugar beet waste and sugarcane bagasse to ethanol. The chemical composition of these feedstocks was determined. Conversion of wastes to free sugars by acid hydrolysis varied from one treatment to another. In single-stage dilute acid hydrolysis, increasing acid concentration from 1 % (v/v to 5 % (v/v decreased the conversion percentage of almost all treated agro-industrial wastes. Lower conversion percentages for some treatments were obtained when increasing the residence time from 90 to 120min. The two-stage dilute acid hydrolysis by phosphoric acid (1.0 % v/v followed by sulphuric acid (1.0 % v/v resulted in the highest conversion percentage (41.3 % w/w on treated sugar beet waste. This treatment when neutralized, amended with some nutrients and inoculated with baker's yeast, achieved the highest ethanol concentration (1.0 % v/v. Formation of furfural and hydroxymethylfurfural (HMF were functions of type of acid hydrolysis, acid concentration, residence time and feedstock type. The highest bioconversion of 5 % wastes (37.8 % w/w was recorded on sugar beet waste by Trichoderma viride EMCC 107. This treatment when followed by baker's yeast fermentation, 0.41 % (v/v ethanol and 8.2 % (v/w conversion coefficient were obtained.

  20. Accelerated hydrolysis method to estimate the amino acid content of wheat (Triticum durum Desf.) flour using microwave irradiation.

    Kabaha, Khaled; Taralp, Alpay; Cakmak, Ismail; Ozturk, Levent

    2011-04-13

    The technique of microwave-assisted acid hydrolysis was applied to wholegrain wheat (Triticum durum Desf. cv. Balcali 2000) flour in order to speed the preparation of samples for analysis. The resultant hydrolysates were chromatographed and quantified in an automated amino acid analyzer. The effect of different hydrolysis temperatures, times and sample weights was examined using flour dispersed in 6 N HCl. Within the range of values tested, the highest amino acid recoveries were generally obtained by setting the hydrolysis parameters to 150 °C, 3 h and 200 mg sample weight. These conditions struck an optimal balance between liberating amino acid residues from the wheat matrix and limiting their subsequent degradation or transformation. Compared to the traditional 24 h reflux method, the hydrolysates were prepared in dramatically less time, yet afforded comparable ninhydrin color yields. Under optimal hydrolysis conditions, the total amino acid recovery corresponded to at least 85.1% of the total protein content, indicating the efficient extraction of amino acids from the flour matrix. The findings suggest that this microwave-assisted method can be used to rapidly profile the amino acids of numerous wheat grain samples, and can be extended to the grain analysis of other cereal crops. PMID:21375298

  1. APPLICATION OF A PSEUDO-KINETIC GENERALIZED SEVERITY MODEL TO THE CONCENTRATED SULFURIC ACID HYDROLYSIS OF PINEWOOD AND ASPENWOOD

    Kando K. Janga,

    2012-05-01

    Full Text Available The yield of monosaccharides after two-stage concentrated sulfuric acid hydrolysis of softwood (Scots pine and hardwood (trembling aspen was modeled using a generalized severity parameter with a time-independent rate constant. The severity parameter, which combines the major operating variables acid concentration, temperature, and reaction time in the decrystallization stage into a single reaction ordinate, was successfully used to describe monosaccharide yields after a standardized hydrolysis stage. Conversion of cellulose to glucose demanded a higher severity to reach maximum glucose yields than the conversion of hemicelluloses to their respective monosaccharides, and the conversion of pine demanded a higher severity to obtain maximum monosaccharide yields as compared to aspen. The results indicate that the generalized severity parameter can be a useful tool for the prediction of sugar yields in a two-stage concentrated sulfuric acid hydrolysis process.

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

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

    2015-01-01

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

  3. Adsorption and hydrolysis of isocyanic acid on TiO2

    The interaction of isocyanic acid (HNCO) with titania in the anatase modification has been investigated by means of DRIFT spectroscopy and TPD experiments. HNCO adsorbs dissociatively on TiO2 to yield isocyanate (NCO) groups, bound to Ti4+ sites, and hydroxyl (OH) groups. The stability of these NCO groups decreases with increasing temperatures, and at T>200oC they are very easily removed from the surface. In the presence of water, the hydrolysis of the NCO species to ammonia is also fostered by elevating the temperature. Moreover, HNCO adsorption on a sample previously exposed to ammonia revealed that competitive adsorption occurs on the surface. The catalytic activity of TiO2 for the hydrolyis of HNCO was investigated in a micro plug-flow reactor and correlated with the stability and reactivity of the isocyanate species found by DRIFT spectroscopy. The results are discussed in view of the role of the HNCO hydrolysis in the selective catalytic reduction (SCR) of diesel NOx emissions with urea (urea-SCR process). (author)

  4. Bioethanol Production from Coconut Fiber Using Alkaline Pretreatment and Acid Hydrolysis Method

    Asyeni Miftahul Jannah

    2015-01-01

    Full Text Available Supporting Indonesia government program to decrease fuel consumption, using renewable energy such of bioethanol is one of the best ways. This research was done in order to utilize agriculture waste (coconut fiber as raw material to produce bioetanol. However, coconut fiber contents lignin that will inhibit conversion process of glucose into ethanol. In this research, pretreatment steps aim to release and breakdown lignin in coconut fiber. Pretreatment was conducted by using alkaline method with 3% Sodium Hydroxide solution. Hydrolysis method was used to produce glucose by using Sulfuric Acid solution with various concentrations (1%, 2%, 3%, and 4 % while in fermentation process used Saccharomyces cerevisiae with various times (5, 7, 9, and 11 days and distillation used to get pure product of bioethanol. The results showed that higher H2SO4 concentration using on hydrolysis process made more glucose converted to bioethanol. The highest bioethanol content produced was 5.9420% from sample of 4% H2SO4 in 7 days of fermentation.

  5. Enantioselective Hydrolysis of Amino Acid Esters Promoted by Bis(β-cyclodextrin) Copper Complexes

    Xue, Shan-Shan; Zhao, Meng; Ke, Zhuo-Feng; Cheng, Bei-Chen; Su, Hua; Cao, Qian; Cao, Zhen-Kun; Wang, Jun; Ji, Liang-Nian; Mao, Zong-Wan

    2016-02-01

    It is challenging to create artificial catalysts that approach enzymes with regard to catalytic efficiency and selectivity. The enantioselective catalysis ranks the privileged characteristic of enzymatic transformations. Here, we report two pyridine-linked bis(β-cyclodextrin) (bisCD) copper(II) complexes that enantioselectively hydrolyse chiral esters. Hydrolytic kinetic resolution of three pairs of amino acid ester enantiomers (S1-S3) at neutral pH indicated that the “back-to-back” bisCD complex CuL1 favoured higher catalytic efficiency and more pronounced enantioselectivity than the “face-to-face” complex CuL2. The best enantioselectivity was observed for N-Boc-phenylalanine 4-nitrophenyl ester (S2) enantiomers promoted by CuL1, which exhibited an enantiomer selectivity of 15.7. We observed preferential hydrolysis of L-S2 by CuL1, even in racemic S2, through chiral high-performance liquid chromatography (HPLC). We demonstrated that the enantioselective hydrolysis was related to the cooperative roles of the intramolecular flanking chiral CD cavities with the coordinated copper ion, according to the results of electrospray ionization mass spectrometry (ESI-MS), inhibition experiments, rotating-frame nuclear Overhauser effect spectroscopy (ROESY), and theoretical calculations. Although the catalytic parameters lag behind the level of enzymatic transformation, this study confirms the cooperative effect of the first and second coordination spheres of artificial catalysts in enantioselectivity and provides hints that may guide future explorations of enzyme mimics.

  6. Methane production from acid hydrolysates of Agave tequilana bagasse: evaluation of hydrolysis conditions and methane yield.

    Arreola-Vargas, Jorge; Ojeda-Castillo, Valeria; Snell-Castro, Raúl; Corona-González, Rosa Isela; Alatriste-Mondragón, Felipe; Méndez-Acosta, Hugo O

    2015-04-01

    Evaluation of diluted acid hydrolysis for sugar extraction from cooked and uncooked Agave tequilana bagasse and feasibility of using the hydrolysates as substrate for methane production, with and without nutrient addition, in anaerobic sequencing batch reactors (AnSBR) were studied. Results showed that the hydrolysis over the cooked bagasse was more effective for sugar extraction at the studied conditions. Total sugars concentration in the cooked and uncooked bagasse hydrolysates were 27.9 g/L and 18.7 g/L, respectively. However, 5-hydroxymethylfurfural was detected in the cooked bagasse hydrolysate, and therefore, the uncooked bagasse hydrolysate was selected as substrate for methane production. Interestingly, results showed that the AnSBR operated without nutrient addition obtained a constant methane production (0.26 L CH4/g COD), whereas the AnSBR operated with nutrient addition presented a gradual methane suppression. Molecular analyses suggested that methane suppression in the experiment with nutrient addition was due to a negative effect over the archaeal/bacterial ratio. PMID:25647030

  7. The shape and size distribution of crystalline nanoparticles prepared by acid hydrolysis of native cellulose.

    Elazzouzi-Hafraoui, Samira; Nishiyama, Yoshiharu; Putaux, Jean-Luc; Heux, Laurent; Dubreuil, Frédéric; Rochas, Cyrille

    2008-01-01

    The shape and size distribution of crystalline nanoparticles resulting from the sulfuric acid hydrolysis of cellulose from cotton, Avicel, and tunicate were investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM) as well as small- and wide-angle X-ray scattering (SAXS and WAXS). Images of negatively stained and cryo-TEM specimens showed that the majority of cellulose particles were flat objects constituted by elementary crystallites whose lateral adhesion was resistant against hydrolysis and sonication treatments. Moreover, tunicin whiskers were described as twisted ribbons with an estimated pitch of 2.4-3.2 microm. Length and width distributions of all samples were generally well described by log-normal functions, with the exception of tunicin, which had less lateral aggregation. AFM observation confirmed that the thickness of the nanocrystals was almost constant for a given origin and corresponded to the crystallite size measured from peak broadening in WAXS spectra. Experimental SAXS profiles were numerically simulated, combining the dimensions and size distribution functions determined by the various techniques. PMID:18052127

  8. DETERMINATION OF AMINO ACIDS IN TWO POLYSIPHONIA SPECIES AND STUDY OF ENZYMATIC HYDROLYSIS METHOD

    张立新; 范晓; 魏玉西

    2002-01-01

    The total content of the rich amino acids in two common red algae, Polysiphoni a urceolata and Polysiphonia japonica growing in the Qingdao seashore were d etermi ned. The algae powder was hydrolyzed by 6 mol/L HCl at 110℃ for 48 h and determ ined by amino acid analyzer. The content was 25.35% and 24.16%, respectively, mu ch higher than that of some other species. In addition, a nutritive liquid with abundant amino acids was prepared (by the enzymatic hydrolysis method using Po lys iphonia urceolata) as raw material for a kind of health beverage. The dried se aweed was decolored by 0.25% KMnO4 and 0.5% active carbon, then enzymalized. In the selection of enzymalizing condition, the orthogonal experimental design w as used. Four factors including kinds of enzyme, quantity of enzyme, temperature and time were studied at 3 leve ls. According to the orthogonal design results, we can choose an optimal condition: hydrolyzing at 45℃ by neutr al proteinase (0.25%, w/w) for 2 h, adjusting pH to 8.5, then adding trypsin (0.25%, w/w) and hydrolyzing for 2 h. F inally the above solution was alkalized by NaOH and neutralized by casein. After the hydrolyzed liquid was fil tered and concentrated, suitable additives were added. The final products contain rich amino acids.

  9. DETERMINATION OF AMINO ACIDS IN TWO POLYSIPHONIA SPECIES AND STUDY OF ENZYMATIC HYDROLYSIS METHOD

    张立新; 范晓; 魏玉西

    2002-01-01

    The total content ot the nch amino acids in two common red algae, Potystpnoma urceolata and Polysiphonia japonica growing in the Qingdao seashore were determined. The algae powder was hydrolyzed by 6 mol/L HC1 at 110℃ for 48 h and determined by amino acid analyzer. The content was 25.35% and 24.16% , respectively, much higher than that of some other species. In addition, a nutritive liquid with abundant amino acids was prepared (by the enzymatic hydrolysis method using Polysiphonia urceolata ) as raw material for a kind of health beverage. The dried seaweed was decolored by 0.25% KMnO4 and 0.5% active carbon, then enzymalized. In the selection of enzymalizing condition, the orthogonal experimental design was used. Four factors including kinds of enzyme, quantity of enzyme, temperature and time were studied at 3 levels. According to the orthogonal design results, we can choose an optimal condition: hydrolyzing at 45℃ by neutral proteinase (0.25% , w/w) for 2 h, adjusting pH to 8.5, then adding trypsin (0.25% , w/w) and hydrolyzing for 2 h. Finally the above solution was alkalized by NaOH and neutralized by casein. After the hydrolyzed liquid was filtered and concentrated, suitable additives were added. The final products contain rich amino acids.

  10. Determination of amino acids in two Polysiphonia species and study of enzymatic hydrolysis method

    Zhang, Li-Xin; Fan, Xiao; Wei, Yu-Xi

    2002-09-01

    The total content of the rich amino acids in two common red algae, Polysiphonia urceolata and Polysiphonia japonica growing in the Qingdao seashore were determined. The algae powder was hydrolyzed by 6 mol/L HCl at 110°C for 48 h and determined by amino acid analyzer. The content was 25.35% and 24.16%, respectively, much higher than that of some other species. In addition, a nutritive liquid with abundant amino acids was prepared (by the enzymatic hydrolysis method using Polysiphonia urceolata) as raw material for a kind of health beverage. The dried seaweed was decolored by 0.25% KMnO4 and 0.5% active carbon, then enzymalized. In the selection of enzymalizing condition, the orthogonal experimental design was used. Four factors including kinds of enzyme, quantity of enzyme, temperature and time were studied at 3 levels. According to the orthogonal design results, we can choose an optimal condition: hydrolyzing at 45°C by neutral proteinase (0.25%, w/w) for 2h, adjusting pH to 8.5, then adding trypsin (0.25%, w/w) and hydrolyzing for 2 h. Finally the above solution was alkalized by NaOH and neutralized by casein. After the hydrolyzed liquid was filtered and concentrated, suitable additives were added. The final products contain rich amino acids.

  11. Cellulose nanocrystals prepared via formic acid hydrolysis followed by TEMPO-mediated oxidation.

    Li, Bin; Xu, Wenyang; Kronlund, Dennis; Määttänen, Anni; Liu, Jun; Smått, Jan-Henrik; Peltonen, Jouko; Willför, Stefan; Mu, Xindong; Xu, Chunlin

    2015-11-20

    Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached chemical pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc. PMID:26344319

  12. Bioreversible Derivatives of Phenol. 2. Reactivity of Carbonate Esters with Fatty Acid-like Structures Towards Hydrolysis in Aqueous Solutions

    Claus Larsen

    2007-10-01

    Full Text Available A series of model phenol carbonate ester prodrugs encompassing derivatives with fatty acid-like structures were synthesized and their stability as a function of pH (range 0.4 – 12.5 at 37°C in aqueous buffer solutions investigated. The hydrolysis rates in aqueous solutions differed widely, depending on the selected pro-moieties (alkyl and aryl substituents. The observed reactivity differences could be rationalized by the inductive and steric properties of the substituent groups when taking into account that the mechanism of hydrolysis may change when the type of pro-moiety is altered, e.g. n-alkyl vs. t-butyl. Hydrolysis of the phenolic carbonate ester 2-(phenoxycarbonyloxy-acetic acid was increased due to intramolecular catalysis, as compared to the derivatives synthesized from ω-hydroxy carboxylic acids with longer alkyl chains. The carbonate esters appear to be less reactive towards specific acid and base catalyzed hydrolysis than phenyl acetate. The results underline that it is unrealistic to expect that phenolic carbonate ester prodrugs can be utilized in ready to use aqueous formulations. The stability of the carbonate ester derivatives with fatty acid-like structures, expected to interact with the plasma protein human serum albumin, proved sufficient for further in vitro and in vivo evaluation of the potential of utilizing HSA binding in combination with the prodrug approach for optimization of drug pharmacokinetics.

  13. Effect of degree of hydrolysis of whey protein on in vivo plasma amino acid appearance in humans

    Farup, Jean; Rahbek, Stine Klejs; Storm, Adam C; Klitgaard, Søren; Jørgensen, Henry; Bibby, Bo M; Serena, Anja; Vissing, Kristian

    2016-01-01

    Whey protein is generally found to be faster digested and to promote faster and higher increases in plasma amino acid concentrations during the immediate ~60 min following protein ingestion compared to casein. The aim of the present study was to compare three different whey protein hydrolysates...... with varying degrees of hydrolysis (DH, % cleaved peptide bonds) to evaluate if the degree of whey protein hydrolysis influences the rate of amino acid plasma appearance in humans. A casein protein was included as reference. The three differentially hydrolysed whey proteins investigated were: High...... fractions were evaluated in a rat study. A two-compartment model for the description of the postprandial plasma amino acid kinetics was applied to investigate the rate of postprandial total amino acid plasma appearance of the four protein products. The plasma amino acid appearance rates of the three whey...

  14. Structure of Human Acid Sphingomyelinase Reveals the Role of the Saposin Domain in Activating Substrate Hydrolysis.

    Xiong, Zi-Jian; Huang, Jingjing; Poda, Gennady; Pomès, Régis; Privé, Gilbert G

    2016-07-31

    Acid sphingomyelinase (ASM) is a lysosomal phosphodiesterase that catalyzes the hydrolysis of sphingomyelin to produce ceramide and phosphocholine. While other lysosomal sphingolipid hydrolases require a saposin activator protein for full activity, the ASM polypeptide incorporates a built-in N-terminal saposin domain and does not require an external activator protein. Here, we report the crystal structure of human ASM and describe the organization of the three main regions of the enzyme: the N-terminal saposin domain, the proline-rich connector, and the catalytic domain. The saposin domain is tightly associated along an edge of the large, bowl-shaped catalytic domain and adopts an open form that exposes a hydrophobic concave surface approximately 30Å from the catalytic center. The calculated electrostatic potential of the enzyme is electropositive at the acidic pH of the lysosome, consistent with the strict requirement for the presence of acidic lipids in target membranes. Docking studies indicate that sphingomyelin binds with the ceramide-phosphate group positioned at the binuclear zinc center and molecular dynamic simulations indicate that the intrinsic flexibility of the saposin domain is important for monomer-dimer exchange and for membrane interactions. Overall, ASM uses a combination of electrostatic and hydrophobic interactions to cause local disruptions of target bilayers in order to bring the lipid headgroup to the catalytic center in a membrane-bound reaction. PMID:27349982

  15. Enzymatic hydrolysis and fermentability of corn stover pretreated by lactic acid and/or acetic acid

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-01-01

    Four different pretreatments with and without addition of low concentration organic acids were carried out on corn stover at 195 °C for 15 min. The highest xylan recovery of 81.08% was obtained after pretreatment without acid catalyst and the lowest of 58.78% after pretreatment with both acetic and...

  16. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

    Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL

  17. Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J., E-mail: rbrown@mun.ca

    2014-09-05

    Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

  18. APPLICATION OF A PSEUDO-KINETIC GENERALIZED SEVERITY MODEL TO THE CONCENTRATED SULFURIC ACID HYDROLYSIS OF PINEWOOD AND ASPENWOOD

    Kando K. Janga,; Karin Øyaas,; Terje Hertzberg; Størker T Moe

    2012-01-01

    The yield of monosaccharides after two-stage concentrated sulfuric acid hydrolysis of softwood (Scots pine) and hardwood (trembling aspen) was modeled using a generalized severity parameter with a time-independent rate constant. The severity parameter, which combines the major operating variables acid concentration, temperature, and reaction time in the decrystallization stage into a single reaction ordinate, was successfully used to describe monosaccharide yields after a standardized hydroly...

  19. Hydrolysis of tanned leather wastes under alkaline, acidic and oxidative conditions

    Botić Tatjana

    2006-01-01

    Full Text Available Different wastes in large quantities are the outcome or the by-product of processes in the tanning industry. The largest part of solid wastes is collagen based and obtained in the reprocessing steps of tanned and non-tanned products. The quality collagen substance obtained from wastes of the leather industry used as a supporting material in many reprocessing industries. Hydrolysis is the basic step of collagen processing, namely the shortening of its polypeptide chain. The main goal of this investigation was to examine the influence of the following parameters on the extent of collagen hydrolysis: type and quantity of reagent used for hydrolysis temperature of hydrolysis, pH, duration of hydrolysis as well as the dimensions of the "shavings" samples. The change of molar mass during hydrolysis was monitored by UV-spectroscopy. Special attention was paid to the dechroming process of the collagen hydrolysate.

  20. Hydrolysis characteristics of sugarcane bagasse pretreated by dilute acid solution in a microwave irradiation environment

    Highlights: ► Pretreatment of sugarcane bagasse via dilute sulfuric acid is studied. ► The concentration of the dilute sulfuric acid is in the range of 0–0.02 M. ► Around 40–44 wt% of bagasse is degraded from the pretreatment. ► Around 80–98% of hemicellulose in bagasse is hydrolyzed. ► The optimal operation of the pretreatment occurs at 0.005 M. - Abstract: Pretreatment of lignocellulosic biomass is of the utmost importance for the development of bioethanol because of the abundance and low cost of lignocelluloses. To figure out the hydrolysis characteristics of sugarcane bagasse in a microwave irradiation environment, the biomass is pretreated by a dilute sulfuric acid solution at 180 °C for 30 min, with the concentration ranging from 0 to 0.02 M. A variety of analyses, including fiber analysis, TGA, XRD, FTIR and HPLC, are employed to aid in understanding the physical and chemical characteristics of residual solid particles and solutions. A higher concentration is conducive to destroying bagasse; however, the buffering capacity possessed by the biomass is also observed in the pretreatment. The experimental results indicate that around 40–44 wt% of bagasse is degraded from the pretreatment in which around 80–98% of hemicellulose is hydrolyzed. In contrast, crystalline cellulose and lignin are hardly affected by the pretreatment. The maximum yields of xylose and glucose as well as the minimum furfural selectivity occur at the acid concentration of 0.005 M. Consequently, the aforementioned concentration is recommended for bagasse pretreatment and bioethanol production.

  1. Optimization studies on acid hydrolysis of oil palm empty fruit bunch fiber for production of xylose.

    Rahman, S H A; Choudhury, J P; Ahmad, A L; Kamaruddin, A H

    2007-02-01

    Oil palm empty fruit bunch fiber is a lignocellulosic waste from palm oil mills. It is a potential source of xylose which can be used as a raw material for production of xylitol, a high value product. The increasing interest on use of lignocellulosic waste for bioconversion to fuels and chemicals is justifiable as these materials are low cost, renewable and widespread sources of sugars. The objective of the present study was to determine the effect of H(2)SO(4) concentration, reaction temperature and reaction time for production of xylose. Batch reactions were carried out under various reaction temperature, reaction time and acid concentrations and Response Surface Methodology (RSM) was followed to optimize the hydrolysis process in order to obtain high xylose yield. The optimum reaction temperature, reaction time and acid concentration found were 119 degrees C, 60 min and 2%, respectively. Under these conditions xylose yield and selectivity were found to be 91.27% and 17.97 g/g, respectively. PMID:16647852

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

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

    2008-09-01

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

  3. Glutamic acid production from wheat by-products using enzymatic and acid hydrolysis

    Sari, Y.W.; Alting, A.C.; Floris, R.; Sanders, J.P.M.; Bruins, M.E.

    2014-01-01

    Glutamic acid (Glu) has potential as feedstock for bulk chemicals production. It has also been listed as one of the top twelve chemicals derived from biomass. Large amounts of cheaper Glu can be made available by enabling its production from biomass by-products, such as wheat dried distillers grains

  4. Kinetic analysis of waste activated sludge hydrolysis and short-chain fatty acids production at pH 10

    FENG Leiyu; YAN Yuanyuan; CHEN Yinguang

    2009-01-01

    The accumulation of short-chain fatty acids (SCFAs), a preferred carbon source for enhanced biological phosphorus removal microbes, was significantly improved when waste activated sludge (WAS) was fermented at pH 10. The kinetics of WAS hydrolysis and SCFAs production at pH 10 were investigated. It was observed that during WAS anaerobic fermentation at pH 10 the accumulation of SCFAs was limited by the hydrolysis process, and both the hydrolysis of WAS particulate COD and the accumulation of SCFAs followed first-order kinetics. The hydrolysis and SCFAs accumulation rate constants increased with a increasing of temperature from 10 to 35℃, which could be described by the Arrhenius equation. The kinetic data further indicated that SCFAs production at pH 10 was a biological process. Compared with the experiment of pH uncontrolled (blank test), both the rate constants of WAS hydrolysis and SCFAs accumulation at 20℃ were significantly improved when WAS was fermented at pH 10.

  5. Conversion of levulinic acid into γ-valerolactone using Fe3(CO)12: mimicking a biorefinery setting by exploiting crude liquors from biomass acid hydrolysis.

    Metzker, Gustavo; Burtoloso, Antonio C B

    2015-09-28

    The conversion of biomass-derived levulinic acid (LA) into gamma-valerolactone (GVL) using formic acid (FA) and Fe3(CO)12 as the catalyst precursor was achieved in 92% yield. To mimic a biorefinery setting, crude liquor (containing 20% LA) from the acid hydrolysis of sugarcane biomass in a pilot plant facility was directly converted into GVL in good yield (50%), without the need for isolating LA. PMID:26258183

  6. [Determination of docosahexaenoic acid in milk powder by gas chromatography using acid hydrolysis].

    Shao, Shiping; Xiang, Dapeng; Li, Shuang; Xi, Xinglin; Chen, Wenrui

    2015-11-01

    A method to determine docosahexenoic acid (DHA) in milk powder by gas chromatography was established. The milk powder samples were hydrolyzed with hydrochloric acid, extracted to get total fatty acids by Soxhlet extractor, then esterified with potassium hydroxide methanol solution to form methyl esters, and treated with sodium hydrogen sulfate. The optimal experiment conditions were obtained from orthogonal experiment L9(3(3)) which performed with three factors and three levels, and it requires the reaction performed with 1 mol/L potassium hydroxide solution at 25 degrees C for 5 min. The derivative treated with sodium hydrogen sulfate was separated on a column of SP-2560 (100 m x 0.25 mm x 0.20 μm), and determined in 55 min by temperature programming-gas chromatography. Good linearity was obtained in the range 5.0-300 mg/L with the correlation coefficient of 0.999 9. The relative standard deviations (RSDs) were 3.4%, 1.2% and 1.1% for the seven repeated experiments of 10, 50 and 100 mg/L of DHA, respectively. The limit of detection was 2 mg/kg, and the recoveries of DHA were in the range of 90.4%-93.5%. The results are satisfactory through the tests of practical samples. PMID:26939370

  7. Valorisation of food waste via fungal hydrolysis and lactic acid fermentation with Lactobacillus casei Shirota.

    Kwan, Tsz Him; Hu, Yunzi; Lin, Carol Sze Ki

    2016-10-01

    Food waste recycling via fungal hydrolysis and lactic acid (LA) fermentation has been investigated. Hydrolysates derived from mixed food waste and bakery waste were rich in glucose (80.0-100.2gL(-1)), fructose (7.6gL(-1)) and free amino nitrogen (947-1081mgL(-1)). In the fermentation with Lactobacillus casei Shirota, 94.0gL(-1) and 82.6gL(-1) of LA were produced with productivity of 2.61gL(-1)h(-1) and 2.50gL(-1)h(-1) for mixed food waste and bakery waste hydrolysate, respectively. The yield was 0.94gg(-1) for both hydrolysates. Similar results were obtained using food waste powder hydrolysate, in which 90.1gL(-1) of LA was produced with a yield and productivity of 0.92gg(-1) and 2.50gL(-1)h(-1). The results demonstrate the feasibility of an efficient bioconversion of food waste to LA and a decentralized approach of food waste recycling in urban area. PMID:26873283

  8. Comparative theoretical studies of the phosphomonoester hydrolysis mechanism by purple acid phosphatases.

    Retegan, M; Milet, A; Jamet, H

    2010-07-01

    We present here the first ONIOM (our own n-layered integrated molecular orbital + molecular mechanics method) studies of a purple acid phosphatase enzyme. Our study focused on the structures of the red kidney bean PAP (kbPAP) complexed with phosphate and with phenyl phosphate and on the mechanism of the phenyl phosphate hydrolysis by the enzyme. Density functional theory (DFT) calculations were also performed using models of different sizes for comparison purpose. Results show that the inclusion of three histidine residues, His202, His295, and His296, with their protein surrounding, is crucial to properly describe the coordination of the substrates. They induce a conformation with the substrate closer to the nucleophilic mu-hydroxyde bridge. In the mechanistic study, a transition state is stabilized by a strong hydrogen bond between His202 and the leaving group of the substrate. Consequently, a smaller value for the activation energy barrier is obtained from DFT calculations including this histidine to the same calculations without this histidine. Using the ONIOM method, this activation energy barrier is even more reduced. So the mechanism, which considers the hydroxo group bridging the two metal ions as nucleophile, becomes really convincing, contrary to the results obtained with a small model at the DFT level. PMID:20550096

  9. Acid-Promoted Hydrolysis of m-Cl-Phenyl Phosphorotriamidate leading to its Highly Basic Nature by Kinetic Means

    Harish Kumar Amb

    2015-06-01

    Full Text Available Hydrolysis of m-Cl-Phenyl Phosphorotriamidate has been performed in the acid range, 0.01 to 7.0 M –HCl,in 12%AcoH-H2O (v/v at 98(±0.5oC. The continuous second-order rate rise with the absence of a rate maximum in the entire acid range is significant, leading to its highly basic nature. In this respect, it differs from other related(o-Cl-Ph-&p-Cl-Ph- members of the phosphorotriamidate group. The salt effect variable study leads to the presence and reactivity of the two major reactive species with the Neutral Species(I working in the entire acid range; while the Conjugate acid form(II was observed operating between 4.0-7.0 M HCl region only. Both uni-and bi-molecular mechanisms for the two reactive forms with P-N bond fission have been decided for the C-N-P ester. The hydrolysis is shown to be decreased by the action of the series of the nucleophilic reagents and I'shows the optimum effect here. Role of a chloro-group in the unusual meta position in each aryl matix during hydrolysis was particularly the important feature of this study.

  10. Structural Basis for Nucleotide Hydrolysis by the Acid Sphingomyelinase-like Phosphodiesterase SMPDL3A.

    Gorelik, Alexei; Illes, Katalin; Superti-Furga, Giulio; Nagar, Bhushan

    2016-03-18

    Sphingomyelin phosphodiesterase, acid-like 3A (SMPDL3A) is a member of a small family of proteins founded by the well characterized lysosomal enzyme, acid sphingomyelinase (ASMase). ASMase converts sphingomyelin into the signaling lipid, ceramide. It was recently discovered that, in contrast to ASMase, SMPDL3A is inactive against sphingomyelin and, surprisingly, can instead hydrolyze nucleoside diphosphates and triphosphates, which may play a role in purinergic signaling. As none of the ASMase-like proteins has been structurally characterized to date, the molecular basis for their substrate preferences is unknown. Here we report crystal structures of murine SMPDL3A, which represent the first structures of an ASMase-like protein. The catalytic domain consists of a central mixed β-sandwich surrounded by α-helices. Additionally, SMPDL3A possesses a unique C-terminal domain formed from a cluster of four α-helices that appears to distinguish this protein family from other phosphoesterases. We show that SMDPL3A is a di-zinc-dependent enzyme with an active site configuration that suggests a mechanism of phosphodiester hydrolysis by a metal-activated water molecule and protonation of the leaving group by a histidine residue. Co-crystal structures of SMPDL3A with AMP and α,β-methylene ADP (AMPCP) reveal that the substrate binding site accommodates nucleotides by establishing interactions with their base, sugar, and phosphate moieties, with the latter the major contributor to binding affinity. Our study provides the structural basis for SMPDL3A substrate specificity and sheds new light on the function of ASMase-like proteins. PMID:26792860

  11. Effect of Subsequent Dilute Acid and Enzymatic Hydrolysis on Reducing Sugar Production from Sugarcane Bagasse and Spent Citronella Biomass

    Timung, Robinson; Naik Deshavath, Narendra; Goud, Vaibhav V.; Dasu, Venkata V.

    2016-01-01

    This work was aimed at investigating the effect of process parameters on dilute acid pretreatment and enzymatic hydrolysis of spent citronella biomass (after citronella oil extraction) and sugarcane bagasse on total reducing sugar (TRS) yield. In acid pretreatment, the parameters studied were acid concentration, temperature, and time. At the optimized condition (0.1 M H2SO4, 120°C, and 120 min), maximum TRS obtained was 452.27 mg·g−1 and 487.50 mg·g−1 for bagasse and citronella, respectively....

  12. Comparative study of destruction of sodium salt of carboxymethylcellulose in the course of acid hydrolysis under γ-irradiation

    A study was made on the effect of substituent distribution along chain length on hydrolytic and radiation destruction of commercial compound-Na-salt of carboxymethyl cellulose (Na-CMC) with 0.7 substitution degree. Na-CMC was subjected to 60Co γ-irradiation in the air in 0-0.92 MGy dose range; absorbed dose rate was equal to 9.2x10-3 MGy/h. Acidic hydrolysis of Na-CMC was conducted at 100 deg C, 0.09 M HCl during 0.2-4h. Characteristic viscosity and the number of reducing groups were determined in solutions of irradiated and partially hydrolized Na-CMC. It is shown that carboxylmethyl groups produce the protecting effect on glucoside bond breaking during Na-CMC radiation destruction, as in the case of acidic hydrolysis

  13. Effects of waste activated sludge and surfactant addition on primary sludge hydrolysis and short-chain fatty acids accumulation.

    Ji, Zhouying; Chen, Guanlan; Chen, Yinguang

    2010-05-01

    This paper focused on the effects of waste activated sludge (WAS) and surfactant sodium dodecylbenzene sulfonate (SDBS) addition on primary sludge (PS) hydrolysis and short-chain fatty acids (SCFA) accumulation in fermentation. The results showed that sludge hydrolysis, SCFA accumulation, NH(4)(+)-N and PO(4)(3-)-P release, and volatile suspended solids (VSS) reduction were increased by WAS addition to PS, which were further increased by the addition of SDBS to the mixture of PS and WAS. Acetic, propionic and valeric acids were the top three SCFA in all experiments. Also, the fermentation liquids of PS, PS+WAS, and PS+WAS+SDBS were added, respectively, to municipal wastewater to examine their effects on biological municipal wastewater treatment, and the enhancement of both wastewater nitrogen and phosphorus removals was observed compared with no fermentation liquid addition. PMID:20096564

  14. Effect of acid hydrolysis combined with heat moisture treatment on structure and physicochemical properties of corn starch

    Sun, Qingjie; Zhu, Xiaolei; Si, Fumei; Xiong, Liu

    2013-01-01

    Modification of starch led to new products with new desirable properties. Corn starch samples modified by acid hydrolysis combined with heat moisture treatment (AH-HMT) were made by changing pH, moisture content and treated temperature. After modification, swelling power at temperature higher than 75 °C of corn starches decreased while solubility of the starches increased. After AH-HMT, pasting temperature (PT) of all treated starch samples increased. But lower peak viscosity (PKV), trough vi...

  15. Heat integration of an ethanol polygeneration plant based on lignocellulose: Comparing weak acid hydrolysis and enzymatic hydrolysis; Energiintegrerat etanolkombinat baserat paa lignocellulosa - Jaemfoerelse mellan svagsyrahydrolys och enzymhydrolys

    Olsson, Marcus; Nordman, Roger; Taherzadeh, Mohammad

    2011-07-01

    Plants for bioethanol production have been planned in several cities in Sweden, including Boraas. This report provides answers to general questions regarding how such a facility's energy demand is affected by the external integration with a heat and power plant and the internal energy integration between process units. Heat integration of a bioethanol plant means that energy is reused as much as is technically possible; this sets a practical minimum level for the energy demand of the plant. In the study, ethanol production from cellulose has been simulated using Aspen Plus. Weak acid hydrolysis and enzymatic hydrolysis have been simulated, each with 50,000 and 100,000 tonnes of ethanol per year, resulting in four simulation cases. In all cases, heat integration is evaluated using pinch analysis. The steam in the ethanol plant has been covered by steam from a heat and power plant similar to that found today in Boraas. It is important to note that the energy quotas reported here includes energy use for upgrading the residual products. This leads to lower energy quotas than would be the case if the upgrading of residuals were allocated outside of the ethanol production. The conclusions from the project are: - The steam demand of the ethanol plant leads to a reduction in both the electricity and heat production of the heat and power plant. For the weak acid hydrolysis, the electricity loss is relatively high, 26-98%, which will affect the revenue significantly. The loss of electricity production is lower for the enzymatic process: 11-47%. - The difference in decreased electricity between the theoretical case of heating the raw material and the two alternative heating cases is about a factor of two, so the design of the heating of raw material is extremely important. - The reduced heat output of the power plant can, in most cases, be balanced by the surplus heat from the ethanol plant, but to completely balance the shortage, heat over 100 deg C must be used

  16. The Acid Hydrolysis Mechanism of Acetals Catalyzed by a Supramolecular Assembly in Basic Solution

    Pluth, Michael D.; Bergman, Robert G.; Raymond, Kenneth N.

    2008-09-24

    A self-assembled supramolecular host catalyzes the hydrolysis of acetals in basic aqueous solution. The mechanism of hydrolysis is consistent with the Michaelis-Menten kinetic model. Further investigation of the rate limiting step of the reaction revealed a negative entropy of activation ({Delta}S{double_dagger} = -9 cal mol{sup -1}K{sup -1}) and an inverse solvent isotope effect (k(H{sub 2}O)/k(D{sub 2}O) = 0.62). These data suggest that the mechanism of hydrolysis that takes place inside the assembly proceeds through an A-2 mechanism, in contrast to the A-1 mechanism operating in the uncatalyzed reaction. Comparison of the rates of acetal hydrolysis in the assembly with the rate of the reaction of unencapsulated substrates reveals rate accelerations of up to 980 over the background reaction for the substrate diethoxymethane.

  17. The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis) starch

    Roberta Cruz Silveira Thys; Andréia Gomes Aires; Ligia Damasceno Ferreira Marczak; Caciano Pelayo Zapata Noreña

    2013-01-01

    Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine) starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours) and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days), paste freezing and th...

  18. Production of nanocrystalline cellulose from an empty fruit bunches using sulfuric acid hydrolysis: Effect of reaction time on the molecular characteristics

    Al-Dulaimi, Ahmed A.; R, Rohaizu; D, Wanrosli W.

    2015-06-01

    Nanocrystalline cellulose (NCC) was isolated from OPEFB pulp via sulfuric acid hydrolysis. The influence of reaction time to the molecular weight and surface charge of the NCC was investigated. Characterization of the product was carried out using zeta potential measurement and gel permeation chromatography test. Zeta potential measurement showed that the surface negative charge significantly increases with increasing reaction time. Gel permeation chromatography test indicates that molecular weight of NCC change variably with increasing of hydrolysis time. (Keywords: Nanocrystalline cellulose; acid hydrolysis; sulfate content; molecular weight)

  19. Hydrolysis and transesterification of parabens in an aqueous solution in the presence of glycerol and boric acid

    Oldrich Farsa

    2011-06-01

    Full Text Available In a solution containing 0.067% methylparaben, 0.033% propylparaben, 3.4% glycerol and 2.0% boric acid,concentrations of both parabens, 4-hydroxybenzoic acid and 2,3-dihydroxypropyl 4-hydroxybenzoate weremonitored for up to 68 months storage. 4-hydroxybenzoic acid is the main hydrolysis product of parabens,while 2,3-dihydroxypropyl 4-hydroxybenzoate was proposed as the main product of transesterification of parabens with glycerol. Results of an HPLC evaluation of parabens, 4-hydroxybenzoic acid and 2,3-dihydroxypropyl 4-hydroxybenzoate showed that the decomposition of 68 months old samples stored at room temperature did not exceed 2.0%. The stability of both parabens in a medicinal preparation of the statedcomposition has thus been satisfactorily demonstrated after more than 5 years of storage under ambient conditions. The transesterification reaction was shown to influence the chemical stability of parabens to an extent comparable to hydrolysis. Moreover, the presence of 2,3-dihydroxypropyl 4-hydroxybenzoate in the solution containing glycerol and boric acid was confirmed by 1H-NMR spectroscopy.

  20. Isolation of bacterial cellulose nanocrystalline from pineapple peel waste: Optimization of acid concentration in the hydrolysis method

    Anwar, Budiman; Rosyid, Nurul Huda; Effendi, Devi Bentia; Nandiyanto, Asep Bayu Dani; Mudzakir, Ahmad; Hidayat, Topik

    2016-02-01

    Isolation of needle-shaped bacterial cellulose nanocrystalline with a diameter of 16-64 nm, a fiber length of 258-806 nm, and a degree of crystallinity of 64% from pineapple peel waste using an acid hydrolysis process was investigated. Experimental showed that selective concentration of acid played important roles in isolating the bacterial cellulose nanocrystalline from the cellulose source. To achieve the successful isolation of bacterial cellulose nanocrystalline, various acid concentrations were tested. To confirm the effect of acid concentration on the successful isolation process, the reaction conditions were fixed at a temperature of 50°C, a hydrolysis time of 30 minutes, and a bacterial cellulose-to-acid ratio of 1:50. Pineapple peel waste was used as a model for a cellulose source because to the best of our knowledge, there is no report on the use of this raw material for producing bacterial cellulose nanocrystalline. In fact, this material can be used as an alternative for ecofriendly and cost-free cellulose sources. Therefore, understanding in how to isolate bacterial cellulose nanocrystalline from pineapple peel waste has the potential for large-scale production of inexpensive cellulose nanocrystalline.

  1. [The use of enzymatic hydrolysis for isolation of barbituric acid derivatives from blood (as exemplified by phenobarbital and barbamyl)].

    Chuvina, N A; Kolupaeva, A S; Strelova, O Iu; Zabolotskaia, I V; Gorbacheva, T V

    2010-01-01

    Modern isolation techniques by direct extraction with organic solvents or after protein precipitation by various sedimenting or salting-out agents are characterized by low efficiency and do not permit to liberate derivatives of barbituric acid from their complexes with blood proteins. The use of enzymatic hydrolysis makes it possible to break bonds between barbiturates and protein and thereby improve the efficiency of isolation. We performed enzymatic hydrolysis of the model phenobarbital-blood and barbamyl-blood complexes with the use of trypsin, pepsin, chymotrypsin, and papain. The degree of phenobarbital extraction with trypsin and barbamyl was estimated at 62.1 +/- 1.2% and 75.1 +/- 1.6% respectively; in other words, it was 32.7 +/- 1.0% and 51.1 +/- 1.0% higher than that achieved by traditional methods. Certain validation characteristics of the new method are presented. PMID:21265178

  2. Molecular mechanism of acid-catalyzed hydrolysis of peptide bonds using a model compound.

    Pan, Bin; Ricci, Margaret S; Trout, Bernhardt L

    2010-04-01

    The stability of peptide bonds is a critical aspect of biological chemistry and therapeutic protein applications. Recent studies found elevated nonenzymatic hydrolysis in the hinge region of antibody molecules, but no mechanism was identified. As a first step in providing a mechanistic interpretation, this computational study examines the rate-determining step of the hydrolytic reaction of a peptide bond under acidic pH by a path sampling technique using a model compound N-MAA. Most previous computational studies did not include explicit water molecules, whose effects are significant in solution chemistry, nor did they provide a dynamic picture for the reaction process in aqueous conditions. Because no single trajectory can be used to describe the reaction dynamics due to fluctuations at finite temperatures, a variant version of the transition path sampling technique, the aimless shooting algorithm, was used to sample dynamic trajectories and to generate an ensemble of transition trajectories according to their statistical weights in the trajectory space. Each trajectory was computed as the time evolution of the molecular system using the Car-Parrinello molecular dynamics technique. The likelihood maximization procedure and its modification were used in extracting dynamically relevant degrees of freedom in the system, and approximations of the reaction coordinate were compared. Its low log-likelihood score and poor p(B) histogram indicate that the C-O distance previously assumed as the reaction coordinate for the rate-determining step is inadequate in describing the dynamics of the reaction. More than one order parameter in a candidate set including millions of geometric quantities was required to produce a convergent reaction coordinate model; its involvement of many degrees of freedom suggests that this hydrolytic reaction step is very complex. In addition to affecting atoms directly involved in bond-making and -breaking processes, the water network also has

  3. Assay of phenolic compounds from four species of ber (Ziziphus mauritiana L.) fruits: comparison of three base hydrolysis procedure for quantification of total phenolic acids.

    Memon, Ayaz Ali; Memon, Najma; Bhanger, Muhammad Iqbal; Luthria, Devanand L

    2013-08-15

    The present study was undertaken to investigate the flavonoid profile in four species of ber (Ziziphus mauritiana Lamk.) fruit. The 12 flavonoids identified were quercetin 3-O-robinobioside, quercetin 3-O-rutinoside, quercetin 3'-O-galactoside, quercetin 3'-O-glucoside, quercetin 3'-O-rhamnoside, quercetin 3'-O-pentosylhexoside, quercetin 3-O-6'malonylglucoside, quercetin 3'-O-malonylglucoside, luteolin 7-O-6'malonylglucoside, luteolin 7-O-malonylglucoside, myricetin 3-O-galactoside, and naringenin tri glycoside. This is the first report on extraction of nine additional flavonoids from the ber fruits. In addition, we also compared the impact of three different base hydrolysis techniques namely ultrasonic assisted base hydrolysis (UABH), microwave assisted base hydrolysis (MWABH), and pressurised liquid assisted base hydrolysis (PLABH) for the quantification of total phenolic acids. Nine phenolic acids, protocatechuic acid, p-hydroxybenzoic acid, ferulic acid, chlorogenic acid, vanillic acid, caffeic acid, vanillin, ortho- and para-coumaric acids, were identified and quantified. The three major phenolic acids identified in all four ber species were p-coumaric acid, vanillin and ferulic acids. Higher amounts (pacids in all cultivars were obtained with the PLABH technique as compared to other two procedures (UABH and MWABH). PMID:23561136

  4. Hydrolysis of Cellulose Using Mono-Component Enzymes Shows Synergy during Hydrolysis of Phosphoric Acid Swollen Cellulose (PASC), but Competition on Avicel

    Andersen, Natalija; Johansen, Katja S.; Michelsen, Michael Locht; Stenby, Erling Halfdan; Krogh, Kristian B.R.M.; Olsson, Lisbeth

    2008-01-01

    ). In contrast to previous studies, where P-glucosidase was either not added or added in excess, we here focus on engineering binary, as well as, ternary cellulase mixtures (including a range of different mol% of Cel3A) for maximal total sugar production. Precise hydrolysis pattern based on the...... concentration of soluble hydrolysis products (glucose to cellohexaose measured by HPLC) was determined. The importance of proper assay selection for hydrolysis products detection was illustrated. It was found that degree of synergy (DS) for degradation of PASC were generally larger than I (indicating...

  5. Microwave-assisted hydrolysis of organophosphate pesticides leading to their total decomposition up to phosphoric acid

    Čechová, Lucie; Jansa, Petr; Dračínský, Martin; Janeba, Zlatko

    Thessaly: University of Thessaly, 2012. A12-A12. [International Symposium on green chemistry for environment, health and development /3./. 03.10.2012-05.10.2012, Skiathos Island] R&D Projects: GA MV VG20102015046 Institutional research plan: CEZ:AV0Z40550506 Keywords : microwave-assisted hydrolysis * organo Subject RIV: CC - Organic Chemistry

  6. Kinetic Studies on Wheat Straw Hydrolysis to Levulinic Acid%小麦秸秆制备乙酰丙酸的动力学研究

    常春; 马晓建; 岑沛霖

    2009-01-01

    Levulinic acid is considered as a promising green platform chemical derived from biomass. The kinetics of levulinic acid accumulation in the hydrolysis process of wheat straw was investigated in the study. Using dilute sulfuric acid as a catalyst, the kinetic experiments were performed in a temperature range of 190-230℃ and an acid concentration range of 1%-5% (by mass). A simple model of first-order series reactions was developed, which provided a satisfactory interpretation of the experimental results. The kinetics of main intermediates including sugar and 5-hydroxymethylfurfural (5-HMF) were also established. The kinetic parameters provided useful information for understanding the hydrolysis process.

  7. Integration of mild acid hydrolysis in γ-valerolactone/water system for enhancement of enzymatic saccharification from cotton stalk.

    Wu, Miao; Yan, Zhong Ya; Zhang, Xue Ming; Xu, Feng; Sun, Run Cang

    2016-01-01

    In this study, mild acid hydrolysis using γ-valerolactone (GVL)/water system integrated with enzymatic hydrolysis was carried out for the enhancement of enzymatic saccharification efficiency. The quantitative analysis of soluble carbohydrates and structural characterizations of solid residues were conducted. Results showed that the soluble carbohydrates in the water-phase were mainly composed of monomers and oligomers from xylose and glucose, while the contents of which were depended on the ratio of GVL to water. Moreover, the inhibitors were hardly detected due to the moderate pretreatment severity. Compared with the untreated feedstock, the yields of enzymatic hydrolysis from pretreated samples increased by two-fold with the mixture of 80/20 GVL/H2O. Combined with the amount of glucose (14.6%) dissolved in the water-phase, over 92.6% of glucose in cotton stalk was released and recovered. Based on the comprehensive analysis, treatment with GVL/H2O system provided us a more effective approach for sugar production from biomass. PMID:26476160

  8. The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis starch

    Roberta Cruz Silveira Thys

    2013-02-01

    Full Text Available Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days, paste freezing and thawing stability (after six freezing and thawing cycles, swelling power, and solubility. The results of light transmittance (% of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation than that obtained for corn starches after similar storage period. Native pinhão starch (NPS presented lower syneresis than native corn starch (NCS when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS, this property was significantly higher (p < 0.05 when compared to that of acid-thinned corn starch (ACS. From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

  9. Enhanced enzymatic hydrolysis of poplar bark by combined use of gamma ray and dilute acid for bioethanol production

    Chung, Byung Yeoup; Lee, Jae Taek; Bai, Hyoung-Woo; Kim, Ung-Jin; Bae, Hyeun-Jong; Gon Wi, Seung; Cho, Jae-Young

    2012-08-01

    Pretreatment of poplar bark with a combination of sulfuric acid (3%, w/w, H2SO4) and gamma irradiation (0-1000 kGy) was performed in an attempt to enhance enzymatic hydrolysis for bioethanol production. The yields of reducing sugar were slightly increased with an increasing irradiation dose, ranging from 35.4% to 51.5%, with a 56.1% reducing sugar yield observed after dilute acid pretreatment. These results clearly showed that soluble sugars were released faster and to a greater extent in dilute acid-pretreated poplar bark than in gamma irradiation-pretreated bark. When combined pretreatment was carried out, a drastic increase in reducing sugar yield (83.1%) was found compared with individual pretreatment, indicating the possibility of increasing the convertibility of poplar bark following combined pretreatment. These findings are likely associated with cellulose crystallinity, lignin modification, and removal of hemicelluloses.

  10. Hydrolysis of tanned leather wastes under alkaline, acidic and oxidative conditions

    Botić Tatjana; Ilišković Nadežda

    2006-01-01

    Different wastes in large quantities are the outcome or the by-product of processes in the tanning industry. The largest part of solid wastes is collagen based and obtained in the reprocessing steps of tanned and non-tanned products. The quality collagen substance obtained from wastes of the leather industry used as a supporting material in many reprocessing industries. Hydrolysis is the basic step of collagen processing, namely the shortening of its polypeptide chain. The main goal of this i...

  11. Effect of acid hydrolysis combined with heat moisture treatment on structure and physicochemical properties of corn starch.

    Sun, Qingjie; Zhu, Xiaolei; Si, Fumei; Xiong, Liu

    2015-01-01

    Modification of starch led to new products with new desirable properties. Corn starch samples modified by acid hydrolysis combined with heat moisture treatment (AH-HMT) were made by changing pH, moisture content and treated temperature. After modification, swelling power at temperature higher than 75 °C of corn starches decreased while solubility of the starches increased. After AH-HMT, pasting temperature (PT) of all treated starch samples increased. But lower peak viscosity (PKV), trough viscosity (TV) and break down (BD) of most treated starch samples were observed. AH-HMT increased the gel hardness of all treated starches. And the biggest hardness of modified starch gel was 148.419 g, improving 93.471 g compared with native starch gel. The melting temperatures (To, Tp, Tc) of modified starch increased, but the melting range and △H decreased. The X-ray pattern remained practically unchanged with or without AH-HMT. Acid hydrolysis combined with heat moisture treatment (AH-HMT) improved the functional properties of corn starch. PMID:25593372

  12. Characteristics of Bone Gelatin Tilapia (Oreochromis niloticus Processed by Using Hydrolysis With Phosphoric Acid and Papain Enzyme

    Gugun Hidayat

    2016-04-01

    Full Text Available Phosphoric acid and papain enzyme able to hydrolyzing collagen from Tilapia into gelatin . The purpose of this research was to determine the best concentration of phosphoric acid and papain enzyme and to determine the physicochemical characteristic gelatin to from Tilapia fish bone which processed with phosphoric acid and papain enzyme. The first research phase was making bone gelatin tilapia using phosphoric acid at concentration of 4%, 5% and 6%, and the papain enzyme 0.5%, 1% and 1.5%. The second phase was characterize the physicochemical gelatin from the best concentration of phosphoric acid concentration (6% and papain enzyme (1.5%, all treatment done with three repetitions. Analysis of the data using ANOVA with completely randomized (CRD design If there was difference between treatment then continued with Honestly Significant Difference Test (HSDT. The results of the first research phase found the best concentration were 6% of phosphoric acid and 1.5% papain enzyme, its shows by the value gel strength 325,95 and 373,32 g.bloom. The second research phase shows that the the best results obtained in this study was gelatin from 1.5% papain enzyme as hydrolysis agent, the physicochemical characteristic were: 376.21 g.bloom gel strength; viscosity of 7.57 cP; yield 6.30%; protein content of 86.46%; water content of 7.12%; and the pH value of 5.11.

  13. Redox cycles of vitamin E: Hydrolysis and ascorbic acid dependent reduction of 8a-(alkyldioxy)tocopherones

    Liebler, D.C.; Kaysen, K.L.; Kennedy, T.A. (Univ. of Arizona, Tucson (USA))

    1989-12-12

    Oxidation of the biological antioxidant {alpha}-tocopherol (vitamin E; TH) by peroxyl radicals yields 8a-(alkyldioxy)tocopherones, which either may hydrolyze to {alpha}-tocopheryl quinone (TQ) or may be reduced by ascorbic acid to regenerate TH. To define the chemistry of this putative two-electron TH redox cycle, we studied the hydrolysis and reduction of 8a-((2,4-dimethyl-1-nitrilopent-2-yl)dioxyl)tocopherone (1) in acetonitrile/buffer mixtures and in phospholipid liposomes. TQ formation in acetonitrile/buffer mixtures, which was monitored spectrophotometrically, declined with increasing pH and could not be detected above pH 4. The rate of TQ formation from 1 first increased with time and then decreased in a first-order terminal phase. Rearrangement of 8a-hydroxy-{alpha}-tocopherone (2) to TQ displayed first-order kinetics identical with the terminal phase for TQ formation from 1. Both rate constants increased with decreasing pH. Hydrolysis of 1 in acetonitrile/H{sub 2}{sup 18}O yielded ({sup 18}O)TQ. These observations suggest that 1 loses the 8a-(alkyldioxy) moiety to produce the tocopherone cation (T{sup +}), which hydrolyzes to 2, the TQ-forming intermediate. Incubation of either 1 or 2 with ascorbic acid in acetonitrile/buffer yielded TH. Reduction of both 1 and 2 decreased with increasing pH. In phosphatidylcholine liposomes at pH 7, approximately 10% of the T{sup +} generated from 1 was reduced to TH by 5 mM ascorbic acid. The results collectively demonstrate that T{sup +} is the ascorbic acid reducible intermediate in a two-electron TH redox cycle, a process that probably would require biocatalysis to proceed in biological membranes.

  14. Fundamental study of the mechanism and kinetics of cellulose hydrolysis by acids and enzymes

    Gong, C. S.; Chang, M.

    1981-02-01

    There are three basic enzymes e.g., endoglucanase (C/sub x/), exoglucanase (C1) and cellobiase comprising the majority of extracellular cellulase enzymes produced by the cellulolytic mycelial fungi, Trichoderma reesei, and other cellulolytic microorganisms. The kinetics of cellobiase were developed on the basis of applying the pseudo-steady state assumption to hydrolyze cellobiose to glucose. The results indicated that cellobiase was bjected to end-product inhibition by glucose. The kinetic modeling of exoglucanase (C1) with respect to cellodextrins was studied. Both glucose and cellobiose were found to be inhibitors of this enzyme with cellobiose being a stronger inhibitor than glucose. Similarly, endoglucanase (C/sub x) is subject to end-product inhibition by glucose. Crystallinity of the cellulose affects the rate of hydrolysis by cellulases. Hence, the changes in crystallinity of cellulose in relation to chemical pretreatment and enzyme hydrolysis was compared. The study of cellulase biosynthesis resulted in the conclusion that exo-and endo-glucanases are coinduced while cellobiase is synthesized independent of the other two enzymes.

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

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

    2016-05-01

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

  16. Effect of surfactant on hydrolysis products accumulation and short-chain fatty acids (SCFA) production during mesophilic and thermophilic fermentation of waste activated sludge: kinetic studies.

    Zhang, Peng; Chen, Yinguang; Zhou, Qi

    2010-09-01

    In the presence of surfactant sodium dodecylbenzene sulfonate (SDBS) the hydrolysis products accumulation and the short-chain fatty acids (SCFA) production during waste activated sludge fermentation under mesophilic and thermophilic conditions was compared with that at room temperature. In order to understand the mechanism of significant amounts of mesophilic and thermophilic hydrolysis products and SCFA observed in the presence of surfactant, the kinetic models at different SDBS dosages were developed. It was found that SDBS increased the mesophilic and thermophilic hydrolysis rate significantly, and the maximum specific utilization of hydrolysis products increased at low SDBS and decreased at high one. However, the observed maximum specific utilization of SCFA decreased seriously with SDBS increase. In the presence of SDBS the decay rate of acidogenic bacteria not only was lower than that in the absence of SDBS but decreased with the increase of SDBS under either mesophilic or thermophilic conditions. PMID:20409704

  17. An integrated process for the production of platform chemicals and diesel miscible fuels by acid-catalyzed hydrolysis and downstream upgrading of the acid hydrolysis residues with thermal and catalytic pyrolysis.

    Girisuta, Buana; Kalogiannis, Konstantinos G; Dussan, Karla; Leahy, James J; Hayes, Michael H B; Stefanidis, Stylianos D; Michailof, Chrysa M; Lappas, Angelos A

    2012-12-01

    This study evaluates an integrated process for the production of platform chemicals and diesel miscible biofuels. An energy crop (Miscanthus) was treated hydrothermally to produce levulinic acid (LA). Temperatures ranging between 150 and 200 °C, sulfuric acid concentrations 1-5 wt.% and treatment times 1-12 h were applied to give different combined severity factors. Temperatures of 175 and 200 °C and acid concentration of 5 wt.% were found to be necessary to achieve good yield (17 wt.%) and selectivities of LA while treatment time did not have an effect. The acid hydrolysis residues were characterized for their elemental, cellulose, hemicellulose and lignin contents, and then tested in a small-scale pyrolyzer using silica sand and a commercial ZSM-5 catalyst. Milder pretreatment yielded more oil (43 wt.%) and oil O(2) (37%) while harsher pretreatment and catalysis led to more coke production (up to 58 wt.%), less oil (12 wt.%) and less oil O(2) (18 wt.%). PMID:23073094

  18. Acid hydrolysis and molecular density of phytoglycogen and liver glycogen helps understand the bonding in glycogen α (composite particles.

    Prudence O Powell

    Full Text Available Phytoglycogen (from certain mutant plants and animal glycogen are highly branched glucose polymers with similarities in structural features and molecular size range. Both appear to form composite α particles from smaller β particles. The molecular size distribution of liver glycogen is bimodal, with distinct α and β components, while that of phytoglycogen is monomodal. This study aims to enhance our understanding of the nature of the link between liver-glycogen β particles resulting in the formation of large α particles. It examines the time evolution of the size distribution of these molecules during acid hydrolysis, and the size dependence of the molecular density of both glucans. The monomodal distribution of phytoglycogen decreases uniformly in time with hydrolysis, while with glycogen, the large particles degrade significantly more quickly. The size dependence of the molecular density shows qualitatively different shapes for these two types of molecules. The data, combined with a quantitative model for the evolution of the distribution during degradation, suggest that the bonding between β into α particles is different between phytoglycogen and liver glycogen, with the formation of a glycosidic linkage for phytoglycogen and a covalent or strong non-covalent linkage, most probably involving a protein, for glycogen as most likely. This finding is of importance for diabetes, where α-particle structure is impaired.

  19. Kinetic characterization for hemicellulose hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor at moderate conditions

    The kinetic characterization of hemicellulose hydrolysis of corn stover was investigated using a new reactor of dilute acid cycle spray flow-through (DCF) pretreatment. The primary purpose was to obtain kinetic data for hemicellulose hydrolysis with sulfuric acid concentrations (10-30 kg m-3) at relatively low temperatures (90-100 oC). A simplified kinetic model was used to describe its performance at moderate conditions. The results indicate that the rates of xylose formation and degradation are sensitive to flow rate, temperature and acid concentration. Moreover, the kinetic data of hemicellulose hydrolysis fit a first-order reaction model and the experimental data with actual acid concentration after accounting for the neutralization effect of the substrates at different temperatures. Over 90% of the xylose monomer yield and below 5.5% of degradation product (furfural) yield were observed in this reactor. Kinetic constants for hemicellulose hydrolysis models were analyzed by an Arrhenius-type equation, and the activation energy of xylose formation were 111.6 kJ mol-1, and 95.7 kJ mol-1 for xylose degradation, respectively. -- Highlights: → Investigating a novel pretreatment reactor of dilute acid cycle spray flow-through. → Xylose yield is sensitive to flow rate, temperature and acid concentration. → Obtaining relatively higher xylose monomer yield and lower fermentation inhibitor. → Lumping hemicellulose and xylan oligmers together in the model is a valid way. → The kinetic model as a guide for reactor design, and operation strategy optimization.

  20. Comparative analysis of the effect of pretreating aspen wood with aqueous and aqueous-organic solutions of sulfuric and nitric acid on its reactivity during enzymatic hydrolysis

    Dotsenko, Gleb; Osipov, D. O.; Zorov, I. N.;

    2016-01-01

    The effect of aspen wood pretreatment methods with the use of both aqueous solutions of sulfuric and nitric acids and aqueous-organic solutions (ethanol, butanol) of sulfuric acid (organosolv) on the limiting degree of conversion of this type of raw material into simple sugars during enzymatic...... hydrolysis are compared. The effects of temperature, acid concentration, composition of organic phase (for sulfuric acid), and pressure (for nitric acid) on the effectiveness of pretreatment were analyzed. It is shown that the use of organosolv with 0.5% sulfuric acid allows us to increase the reactivity of...

  1. New steroidal sapogenins from the acid hydrolysis product of the whole glycoside mixture of Welsh onion seeds

    Wei Lai; Ying Bo Yang; Xia Li; Lian Na Sun; Zhi Jun Wu; Wan Sheng Chen

    2012-01-01

    Two new steroidal sapogenins (1,2) along with five known steroidal sapogenins were isolated from the acid hydrolysis product of the whole glycoside mixture of Welsh onion (Allium fistulosum L.) seeds.Based on comprehensive spectroscopic analyses,including 2D NMR spectroscopy and mass spectrometry,their structures were elucidated as (25R)-19-norspirosta-1,3,5 (10)-triene-4-methyl-2-ol (1),(25R)-spirost-1,4-diene-3-one-2,6-diol (2),(25R)-spirost-1,4-diene-3-one-2-ol (3),(25R)-spirost-4-ene-3-one-2-ol (4),yuccagenin (5),gitogenin (6) and tigogenin (7).

  2. Influence of temperature, time, liquid/solid ratio and sulfuric acid concentration on the hydrolysis of palm empty fruit bunches.

    Ferrer, Ana; Requejo, Ana; Rodríguez, Alejandro; Jiménez, Luis

    2013-02-01

    The influence of temperature (150-190 °C), time (0-20 min), liquid/solid ratio (6-8) and sulfuric acid concentration (0.1-0.5%), on the hydrolysis of palm empty fruit bunches (EFBs) was studied and the liquid and solid fractions were analyzed. Polynomial models were found to reproduce the experimental results with errors less than 15% in most of the cases (except for xylose concentration). Operating conditions of 190 °C for 15 min at a liquid/solid ratio of 6 and a sulfuric acid concentration of 0.1% resulted in the production of 3.12, 4.0, 2.35 and 2.28 g/L of glucose, xylose, arabinose and acetic acid, respectively, starting with 1000 g of EFBs. The yield was 67.96%. Soda-anthraquinone, ethanol and ethanolamine pulping of the solid fraction provided pulps with brightness values (63.24%, 28.78%, 48.76%), but with poor resistance properties (6.57-8.54 Nm/g for tensile index, 0.38-0.44 k N/g for burst index and 0.96-1.02 mN m2/g for tear index). Therefore it is advisable to use the pulps for speciality papers or for bioethanol-production. PMID:23266852

  3. Revisiting the Brønsted acid catalysed hydrolysis kinetics of polymeric carbohydrates in ionic liquids by in situ ATR-FTIR spectroscopy

    Kunov-Kruse, Andreas Jonas; Riisager, Anders; Shunmugavel, Saravanamurugan;

    2013-01-01

    A new versatile method to measure rates and determine activation energies for the Brønsted acid catalysed hydrolysis of cellulose and cellobiose (and other polymeric carbohydrates) in ionic liquids is demonstrated by following the C–O stretching band of the glycoside bond with in situ ATR-FTIR. A...

  4. Effect of low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis on the production of fermentable substrates and the release of inhibitory compounds

    Panagiotopoulos, I.A.; Lignos, G.D.; Bakker, R.R.C.; Koukios, E.G.

    2012-01-01

    The objective of this work was to investigate the feasibility of combining low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis for the high production of fermentable substrates and the low release of inhibitory compounds. For most of the pretreatments at 160

  5. Amino Acids Production from Fish Proteins Hydrolysis in Subcritical Water%近临界水中水解鱼蛋白制备氨基酸

    朱宪; 朱超; 赵亮; 程洪斌

    2008-01-01

    The hydrolysis technology and reaction kinetics for amino acids production from fish proteins in subcritical water reactor without catalysts were investigated in a reactor with volume of 400ml under the conditions of reaction temperature from 180-320℃, pressure from 5-26MPa, and time from 5-60min. The quality and quantity of amino acids in hydrolysate were determined by bioLiquid chromatography, and 17 kinds of amino acids were obtained. For the important 8 amino acids, the experiments were conducted to examine the effects of reaction temperature, pressure and time on amino acids yield. The optimum conditions for high yield are obtained from the experimental results. It is found that the nitrogen and carbon dioxide atmosphere should be used for leucine, isoleucine and histidine production while the air atmosphere might be used for other amino acids. The reaction time of 30min and the experimental temperature of 220℃, 240℃ and 260℃ were adopted for reaction kinetic research. The total yield of amino acids versus reaction time have been examined experimentally. According to these experimental data and under the condition of water excess, the macroscopic reaction kinetic equation of fish proteins hydrolysis was obtained with the hydrolysis reaction order of 1.615 and the rate constants being 0.0017, 0.0045 and 0.0097 at 220℃, 240℃ and 260℃ respectively. The activation energy is 145.1kJ·mol-1.

  6. Hydrolysis of Pentosan for Furfural Preparing Using Sulfuric Acid Catalyst to Improve Diesel Engine Fuel Quality

    The investigation on furfural preparation from peanut shell using sulfuric acid catalyst has been done. Furfural is an organic solvent used in industry especially petroleum industry. The purpose of this investigation is to know the effects of sulfuric acid concentration and solvent feed ratio towards furfural resulted and the reaction kinetics. The experiment was performed in the batch reactor. The result of this investigation showed that the process optimum condition was reached at sulfuric acid concentration of 7% and the solvent feed ratio of 12.5. The result at the optimum condition above was 5.97% of furfural. The relation between percentage of furfural resulted (Y) and sulfuric acid concentration (X) is Y = 0.893 X1.7023 . e-0.2554X with average deviation of 5.880 %. The relation between percentage of furfural resulted (Y) and solvent feed ratio (X) is Y = -53.0411 + 9.4137 X - 0.3780 X2 with average deviation 5.154 %. The relation between reaction rate constant (Y) and sulfuric acid concentration (X) is Y = 3.1916 . 10-3 + 8.2432 . 10-3 X - 5.2324 . 10-4 X2 with average deviation 8.024 %. (author)

  7. Distribution and Variation of Ribonucleic Acid (RNA) and Protein and Its Hydrolysis Products in Lake Sediments

    梁小兵; 万国江; 黄荣贵

    2002-01-01

    Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition-amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein.The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities.

  8. Acid Pre hydrolysis of the Lignocellulose biomass from thistle Onopordum nervosum Boiss; Prehidrolisis acida de la Biomasa Lignocelulosica del Cardo Onopordum nervosum Boiss

    Suarez Contreras, C.; Paz Saa, D.; Diaz Palma, A.

    1983-07-01

    The acid pre hydrolysis of the lignocellulose biomass from thistle O. nervosum has been conducted to determine the conditions for maximum yield of pentoses with minimum yield of hexoses. Variables studied were acid concentration (H{sub 2}SO{sub 4}, 1 , 3, 4 and 5%) , temperature (1000 and 120 degree centigree) time, solid to liquid ratio and degree of fineness of thistle (1 to 65 mesh). (Author) 15 refs.

  9. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave

    Tong-Chao Su; Zhen Fang; Fan Zhang; Jia Luo; Xing-Kang Li

    2015-01-01

    In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g−1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg−1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% und...

  10. Hydrolysis mechanisms for the organopalladium complex [Pd(CNN)P(OMe)3]BF4 in sulfuric acid.

    García, Begoña; Hoyuelos, Francisco J; Ibeas, Saturnino; Muñoz, María S; Peñacoba, Indalecio; Leal, José M

    2009-08-13

    The acid-catalyzed hydrolysis of the organopalladium complex [Pd(CNN)P(OMe)3]BF4 species was monitored spectrophotometrically at different sulfuric acid concentrations (3.9 and 11.0 M) in 10% v:v ethanol-water over the 25-45 degrees C temperature range and in 30% and 50% (v/v) ethanol-water at 25 degrees C. Two acidity regions (I and II) could be differentiated. In each of the two regions the kinetic data pairs yielded two different rate constants, k(1obs) and k(2obs), the former being faster. These constants were fitted by an Excess Acidity analysis to different hydrolyses mechanisms: A-1, A-2, and A-SE2. In region I ([H2SO4] 7.0 M), a switchover was observed from an A-1 mechanism (k(0,A1) = 1.3 x 10(-4) s(-1)) to an A-2 mechanism (k(0,A2) = 3.6 x 10(-3) M(-1) s(-1)). The temperature effect on the rate constants in 10% (v/v) ethanol-water yielded positive DeltaH and negative DeltaS values, except for the A-1 mechanism, where DeltaS adopted positive values throughout. The solvent permittivity effect, epsilonr, revealed that k(1obs)(av) and k(0,A2) dropped with a fall in epsilonr, whereas the k(0,ASE2) value remained unaffected. The set of results deduced is in line with the schemes put forward. PMID:19621916

  11. Effect of gamma Irradiation on the acidic hydrolysis of free-hemi cellulose thistle; Efecto de la irradiacion gamma en la hidrolisis acida de cardo exento de pentosas

    Suarez, C.; Paz, M. D.; Diaz, A.

    1983-07-01

    The effect of gamma-irradiation on the subsequent acidic hydrolysis of free-hemi cellulose Onopordum Nervosum Boiss thistle Ls determined. Its shown the influence of gamma-irradiation on the yield of sugar obtained flora the batch wise hydrol isis of the call ulose (1% H{sub 2}SO{sub 4} and 180 degree centigree at increasing doses). At all irradiation levels studied, the rate of hydrolysis of thistle samples was higher than the rate of hydrolysis of the cellulose from paper treated similarly. The maximum over-all yield of sugar in the irradiated lignocellulose material was about 66o at 100 MRad, less than two times the yield obtainable from the control. The corresponding yield from papel was 53%, 2'3 times that of the control. Irradiation under 1% H{sub 2}SO{sub 4} doesn't enhance the yield anyway. (Author) 21 refs.

  12. Influence of solid loading on D-xylose production through dilute sulphuric acid hydrolysis of olive stones

    Cuevas, M.

    2015-09-01

    Full Text Available The selective hydrolysis of hemicellulose from olive stones was attempted in order to achieve a maximum D-xylose yield. For this aim, batch hydrolysis was conducted under different operating conditions of temperature, acid concentration and solid loading. Firstly, distilled water, sulphuric acid and nitric acid were assessed as hydrolytic agents at different temperatures (200, 205, 210 and 220 °C and at a fixed acid concentration (0.025 M. Sulphuric acid and 200 °C were selected for the subsequent dilute acid hydrolysis optimization based on the obtained D-xylose yields. The combined influence of solid loading (from 29.3 to 170.7 g olive stones into 300 mL acid solution and sulphuric acid concentration (0.006–0.034 M on the release of D-xylose was then estimated by response surface methodology. According to a statistical analysis, both parameters had significant interaction effects on D-xylose production. The results illustrated that the higher the solid loading, the higher the required acid concentration. The decrease in the solid/liquid ratio in the reactor had a positive effect on D-xylose extraction and on the amount of acid used. The optimum solid loading and sulphuric acid concentration were determined to be 50 g (solid/liquid ratio 1/6 and 0.016 M, respectively. Under these conditions, the predicted D-xylose yield (expressed as g of sugar per 100 g of dry matter fed was 20.4 (87.2% of maximum attainable.Se ha desarrollado una hidrólisis selectiva de la fracción hemicelulósica del hueso de aceituna con el fin de obtener el máximo rendimiento de D-xilosa. Para ello las hidrólisis se llevaron a cabo en un reactor discontinuo a distintas condiciones de temperatura, concentración de ácido y carga de sólidos. En primer lugar se evaluó la capacidad hidrolítica del agua destilada y de los ácidos nítrico y sulfúrico a distintas temperaturas (200, 205, 210 y 220°C manteniendo fija la concentración de ácido (0,025 M. A partir de

  13. 18O isotope effect in 13C nuclear magnetic resonance spectroscopy. Part 9. Hydrolysis of benzyl phosphate by phosphatase enzymes and in acidic aqueous solutions

    The 18O isotope-induced shifts in 13C and 31P nuclear magnetic resonance (NMR) spectroscopy were used to establish the position of bond cleavage in the phosphatase-catalyzed and acid-catalyzed hydrolysis reactions of benzyl phosphate. The application of the 18O-isotope effect in NMR spectroscopy affords a continuous, nondestructive assay method for following the kinetics and position of bond cleavage in the hydrolytic process. The technique provides advantages over most discontinuous methods in which the reaction components must be isolated and converted to volatile derivatives prior to analysis. In the present study, [α-13C,ester-18O]benzyl phosphate and [ester-18O]benzyl phosphate were synthesized for use in enzymatic and nonenzymatic studies. Hydrolysis reactions catalyzed by the alkaline phosphatase from E. coli and by the acid phosphatases isolated from human prostate and human liver were all accompanied by cleavage of the substrate phosphorus-oxygen bond consistent with previously postulated mechanisms involving covalent phosphoenzyme intermediates. An extensive study of the acid-catalyzed hydrolysis of benzyl phosphate at 750C revealed that the site of bond cleavage is dependent on pH. At pH less than or equal to 1.3, the hydrolysis proceeds with C-O bond cleavage; at 1.3 2H]Benzyl phosphate was also synthesized. Hydrolysis of this chiral benzyl derivative demonstrated that the acid-catalyzed C-O bond scission of benzyl phosphate proceeds by an A-1 (S/sub N/1) mechanism with 70% racemization and 30% inversion at carbon. 37 references, 4 figures, 2 tables

  14. PREPARATION OF XYLOSE AND KRAFT PULP FROM POPLAR BASED ON FORMIC/ACETIC ACID /WATER SYSTEM HYDROLYSIS

    Junping Zhuang

    2009-08-01

    Full Text Available A formic/acetic acid/water system was used in the ratios of 30:60:10, 20:60:20, and 30:50:20 separately for efficient hydrolysis and bioconversion of poplar chips, under the solid/liquid ratio of 1:12(g/ml, at 105 oC for 30, 45, 60, 75, and 90 min, respectively. The highest yield of 69.89% was at a formic/acetic acid /water ratio of 30:50:20(v/v/v, with solid/liquid in the ratio of 1:12(g/ml at 105 oC for 90min. Lower kappa number and similar yield were achieved when hydrolytic residual woodchips were used for kraft pulping with over 2% Na2O and temperature 5 °C lower compared to untreated chips. Pulps from prehydrolysis-treated chips were easy to beat. But the tensile index, tear index, and burst index of the handsheets obtained from pulp with lowest kappa number from prehydrolysis-treated poplar chips were lower than those of the pulp from the untreated chips. Considerable xylose could be obtained from the prehydrolysis stage following kraft pulping under the same conditions for prehydrolysis-treated chips and untreated chips. However, by building on the mature kraft pulping and xylitol processes, large amounts of xylose from the hemicellulose were obtained in prehydrolysis, allowing production of high-valued products via biorefinery pathways. An economical balance of chemical dosage, energy consumption, pulp properties, and xylose value for prehydrolysis with organic acid should be reached with further investigation.

  15. Depolymerization of coal by O2 oxidation followed by acid hydrolysis; Sanso sanka-kasui bunkai ni yoru sekitan no teionkai jugo

    Aizawa, S.; Hayashi, J.; Kumagai, H.; Chiba, T. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology; Morooka, S. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    1996-10-28

    With an objective to elucidate characteristics of oxygen addition to coal, and characteristics of solvent extraction by means of depolymerization, experiments were performed on oxygen oxidation and acid hydrolysis of brown coals. Coals used for the experiments are Morwell (MW), Yallourn (YL) , South Banko (SB) and Wyoming (WY) coals. Test samples were suspended in weak alkaline aqueous solution, and then oxygen was blown into them with pressure kept at atmospheric pressure. After a lapse of a predetermined time, the samples were cooled, and made as acidic as pH 1.3 in hydrochloric acid, followed by acid hydrolysis. Oxygen consumption increased with the reaction time, and with the MW coal, one mol oxygen reacted to 11 mols of coal. Spectral analysis on the YL and WY coal experiments revealed that aliphatic carbon combined with aromatic carbon or ether group has turned to peroxide, whose C-C or C-O bond was broken down as a result of acid hydrolysis of the peroxide, producing oxygen containing compounds. As a result of the depolymerization, the rate of extraction by using DMF, DMSO and methanol/THF mixed solvent increased to 90% or higher. Proportion of bond and cutting-off affects largely collapse of the cross-link structure. The carbon conversion to volatiles was at most 4%. 1 ref., 10 figs.

  16. Microwave-Assisted Method for Simultaneous Hydrolysis and Extraction for Preparation of Geniposidic Acid from Eucommia ulmoides Bark Using Basic Imidazolide Ionic Liquid

    Lili Li

    2016-01-01

    Full Text Available In order to hydrolyze geniposide and extract geniposidic acid, a novel microwave irradiation heating method for simultaneous hydrolysis and extraction for preparation of geniposidic acid from Eucommia ulmoides bark using basic imidazolide ionic liquid was developed in this work. Basic ionic liquid paired by imidazolide anion and 1-hexyl-3-methylimidazolium cation ([C6mim]Im was used as a dual hydrolysis catalyst and extraction solvent in the proposed approach. The optimal concentration of [C6mim]Im was 0.4 mol/L. And the independent parameters optimized by Box-Behnken design (BBD based on single-factor tests were as follows: microwave irradiation time of 20 min at power of 415 W and liquid-solid ratio of 15 mL/g. Yield of geniposidic acid was increased to 3.41±0.17 μmol/g. DM130 macroporous resin, after reaction, was selected to separate geniposidic acid from hydrolysate. The plant materials with different treatment were analyzed by scanning electron microscopy (SEM and thermogravimetric analysis (TG. The analysis of SEM and TG further indicated that IMSHE is an efficient preparation method for geniposidic acid. It is reasonable to assume that the method and the dual hydrolysis catalyst and extraction solvent would offer an alternative for the preparation of some other kinds of bioactive substances from plant materials.

  17. Effects of formic acid hydrolysis on the quantitative analysis of radiation-induced DNA base damage products assayed by gas chromatography/mass spectrometry

    Gas chromatography/mass spectrometry (GC/ MS-SIM) is an excellent technique for performing both qualitative and quantitative analysis of DNA base damage products that are formed by exposure to ionizing radiation or by the interaction of intracellular DNA with activated oxygen species. This technique commonly uses a hot formic acid hydrolysis step to degrade the DNA to individual free bases. However, due to the harsh nature of this degradation procedure, the quantitation of DNA base damage products may be adversely affected. Consequently, we examined the effects of various formic acid hydrolysis procedures on the quantitation of a number of DNA base damage products and identified several factors that can influence this quantitation. These factors included (1) the inherent acid stabilities of both the lesions and the internal standards; (2) the hydrolysis temperature; (3) the source and grade of the formic acid; and (4) the sample mass during hydrolysis. Our data also suggested that the N, O-bis (trimethylsilyl)trifluoroacetamide (BSTFA) derivatization efficiency can be adversely affected, presumably by trace contaminants either in the formic acid or from the acid-activated surface of the glass derivatization vials. Where adverse effects were noted, modifications were explored in an attempt to improve the quantitation of these DNA lesions. Although experimental steps could be taken to minimize the influence of these factors on the quantitation of some base damage products, no single procedure solved the quantitation problem for all base lesions. However, a significant improvement in the quantitation was achieved if the relative molecular response factor (RMRF) values for these lesions were generated with authentic DNA base damage products that had been treated exactly like the experimental samples. (orig.)

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

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

    2016-01-01

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

  19. Evaluation of xylitol production using corncob hemicellulosic hydrolysate by combining tetrabutylammonium hydroxide extraction with dilute acid hydrolysis.

    Jia, Honghua; Shao, Tingting; Zhong, Chao; Li, Hengxiang; Jiang, Min; Zhou, Hua; Wei, Ping

    2016-10-20

    In this paper, we produced hemicellulosic hydrolysate from corncob by tetrabutylammonium hydroxide (TBAH) extraction and dilute acid hydrolysis combined, further evaluating the feasibility of the resultant corncob hemicellulosic hydrolysate used in xylitol production by Candida tropicalis. Optimized conditions for corncob hemicellulose extraction by TBAH was obtained via response surface methodology: time of 90min, temperature of 60°C, liquid/solid ratio of 12 (v/w), and TBAH concentration of 55%, resulting in a hemicellulose extraction of 80.07% under these conditions. The FT-IR spectrum of the extracted corncob hemicellulose is consistent with that of birchwood hemicellulose and exhibits specific absorbance of hemicelluloses at 1380, 1168, 1050, and 900cm(-1). In addition, we found that C. tropicalis can ferment the resulting corncob hemicellulosic hydrolysate with pH adjustment and activated charcoal treatment leading to a high xylitol yield and productivity of 0.77g/g and 2.45g/(Lh), respectively. PMID:27474613

  20. Deuterium isotope effects on acid ionization and transition metal hydrolysis at reactor conditions by Raman spectroscopy

    This paper reports the preliminary measurements from an experimental study to measure the small differences between light (H2O) and heavy (D2O) water under reactor operating conditions (250-300 oC, 10 MPa), using Raman spectroscopy. The deuterium isotope effect δpK = pKD2O - pKH2O, for sodium bisulphate NaDSO4 and phosphoric acid D3PO4, has now been determined at temperatures of 25 oC and 80 oC by measuring the isotropic Raman spectra at different concentrations. The results for the pK and ΔpK at 25 oC agree with the literature, confirming the reliability of the method. High temperature cells have been constructed. (author)

  1. In Candida parapsilosis the ATC1 gene encodes for an acid trehalase involved in trehalose hydrolysis, stress resistance and virulence.

    Ruth Sánchez-Fresneda

    Full Text Available An ORF named CPAR2-208980 on contig 005809 was identified by screening a Candida parapsilosis genome data base. Its 67% identity with the acid trehalase sequence from C. albicans (ATC1 led us to designate it CpATC1. Homozygous mutants that lack acid trehalase activity were constructed by gene disruption at the two CpATC1 chromosomal alleles. Phenotypic characterization showed that atc1Δ null cells were unable to grow on exogenous trehalose as carbon source, and also displayed higher resistance to environmental challenges, such as saline exposure (1.2 M NaCl, heat shock (42°C and both mild and severe oxidative stress (5 and 50 mM H2O2. Significant amounts of intracellular trehalose were specifically stored in response to the thermal upshift in both wild type and mutant strains. Analysis of their antioxidant activities revealed that catalase was only triggered in response to heat shock in atc1Δ cells, whereas glutathione reductase was activated upon mild oxidative stress in wild type and reintegrant strains, and in response to the whole set of stress treatments in the homozygous mutant. Furthermore, yeast cells with double CpATC1 deletion were significantly attenuated in non-mammalian infection models, suggesting that CpATC1 is required for the pathobiology of the fungus. Our results demonstrate the involvement of CpAtc1 protein in the physiological hydrolysis of external trehalose in C. parapsilosis, where it also plays a major role in stress resistance and virulence.

  2. Validated Method for the Characterization and Quantification of Extractable and Nonextractable Ellagitannins after Acid Hydrolysis in Pomegranate Fruits, Juices, and Extracts.

    García-Villalba, Rocío; Espín, Juan Carlos; Aaby, Kjersti; Alasalvar, Cesarettin; Heinonen, Marina; Jacobs, Griet; Voorspoels, Stefan; Koivumäki, Tuuli; Kroon, Paul A; Pelvan, Ebru; Saha, Shikha; Tomás-Barberán, Francisco A

    2015-07-29

    Pomegranates are one of the main highly valuable sources of ellagitannins. Despite the potential health benefits of these compounds, reliable data on their content in pomegranates and derived extracts and food products is lacking, as it is usually underestimated due to their complexity, diversity, and lack of commercially available standards. This study describes a new method for the analysis of the extractable and nonextractable ellagitannins based on the quantification of the acid hydrolysis products that include ellagic acid, gallic acid, sanguisorbic acid dilactone, valoneic acid dilactone, and gallagic acid dilactone in pomegranate samples. The study also shows the occurrence of ellagitannin C-glycosides in pomegranates. The method was optimized using a pomegranate peel extract. To quantify nonextractable ellagitannins, freeze-dried pomegranate fruit samples were directly hydrolyzed with 4 M HCl in water at 90 °C for 24 h followed by extraction of the pellet with dimethyl sulfoxide/methanol (50:50, v/v). The method was validated and reproducibility was assessed by means of an interlaboratory trial, showing high reproducibility across six laboratories with relative standard deviations below 15%. Their applicability was demonstrated in several pomegranate extracts, different parts of pomegranate fruit (husk, peels, and mesocarp), and commercial juices. A large variability has been found in the ellagitannin content (150-750 mg of hydrolysis products/g) and type (gallagic acid/ellagic acid ratios between 4 and 0.15) of the 11 pomegranate extracts studied. PMID:26158321

  3. Gas-phase hydrolysis of triplet SO2: A possible direct route to atmospheric acid formation.

    Donaldson, D James; Kroll, Jay A; Vaida, Veronica

    2016-01-01

    Sulfur chemistry is of great interest to the atmospheric chemistry of several planets. In the presence of water, oxidized sulfur can lead to new particle formation, influencing climate in significant ways. Observations of sulfur compounds in planetary atmospheres when compared with model results suggest that there are missing chemical mechanisms. Here we propose a novel mechanism for the formation of sulfurous acid, which may act as a seed for new particle formation. In this proposed mechanism, the lowest triplet state of SO2 ((3)B1), which may be accessed by near-UV solar excitation of SO2 to its excited (1)B1 state followed by rapid intersystem crossing, reacts directly with water to form H2SO3 in the gas phase. For ground state SO2, this reaction is endothermic and has a very high activation barrier; our quantum chemical calculations point to a facile reaction being possible in the triplet state of SO2. This hygroscopic H2SO3 molecule may act as a condensation nucleus for water, giving rise to facile new particle formation (NPF). PMID:27417675

  4. Biological Activities of Hominis Placenta Herbal Acupuncture prepared by Hydrochloric Acid Hydrolysis

    Geun-young Seo

    2010-06-01

    Full Text Available Reactive Oxygen Species(ROS are continuously produced at a high rate as a by-product of aerobic metabolism. Since tissue damage by free radical increases with age, the reactive oxygen species(ROS such as hydrogen peroxide(H2O2, nitric oxide(NO. Several lines of evidence provided that ROS appears to cause to develop aging-related various diseases such as cancer, arthritis, cardiovascular disease. In this study, we have conducted to investigate the biological activities of Hominis Placenta Herbal Acupuncture by measuring total polyphenol content, DPPH radical scavenging, ABTS radical scavenging, Superoxide dismutase(SOD-like activity, Nitrite scavenging ability in vitro. The total polyphenol contents of Hominis Placenta Herbal Acupuncture was 24.6㎖/㎖. Elctron donation ability on DPPH was 49.4%. The 2,2'-azinobis-3-ehtlbezothiazoline-6-sulfonic acid radical decolorization (ABTS was 50.01%, similar to the DPPH free radical scavenging. The superoxide dismutase (SOD-like activities of hominis placenta herbal acupuncture was 50.876%. The nitrite scavenging abilities at pH 1.5, pH 3.0, pH 6.0 were 52.8%, 29.4%, 15.4%, respectively; these abilities decreased as pH increased. We conclude that Hominis Placenta Herbal Acupuncture may be useful as potential sources of antioxidant.

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

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

    2014-01-01

    The marine bioprocessing industry offers great potential to utilize byproducts for fish meal replacement in aquafeeds. Jumbo squid is an important fishery commodity in Mexico, but only the mantle is marketed. Head, fins, guts and tentacles are discarded in spite of being protein-rich byproducts. This study evaluated the use of two jumbo squid byproduct hydrolysates obtained by acid-enzymatic hydrolysis (AEH) and by autohydrolysis (AH) as ingredients in practical diets for shrimp. The hydrolys...

  6. Summary Report on Gamma Radiolysis of TBP/n-dodecane in the Presence of Nitric Acid Using the Radiolysis/Hydrolysis Test Loop

    Dean R. Peterman; Bruce J. Mincher; Catherine L. Riddle; Richard D. Tillotson

    2010-08-01

    Design and installation has been completed for a state-of-the-art radiolysis/hydrolysis test loop system. The system is used to evaluate the effects of gamma radiolysis and acid hydrolysis on the stability and performance of solvent extraction process solvents. The test loop is comprised of two main sections; the solvent irradiation and hydrolysis loop and the solvent reconditioning loop. In the solvent irradiation and hydrolysis loop, aqueous and organic phases are mixed and circulated through a gamma irradiator until the desired absorbed dose is achieved. Irradiation of the mixed phases is more representative of actual conditions in a solvent extraction process. Additionally, the contact of the organic phase with the aqueous phase will subject the solvent components to hydrolysis. This hydrolysis can be accelerated by controlling the system at an elevated temperature. At defined intervals, the organic from the irradiation/hydrolysis loop will be transferred to the solvent reconditioning loop where the solvent is contacted with scrub, strip, and solvent wash solutions which simulate process flowsheet conditions. These two processes are repeated until the total desired dose is achieved. Since all viable solvent extraction components in an advanced fuel cycle must exhibit high radiolytic and hydrolytic stability, this test loop is not limited to any one solvent system but is applicable to all systems of interest. Also, the test loop is not limited to testing of process flowsheets. It is also a valuable tool in support of fundamental research on newly identified extractants/modifiers and the impact of gamma radiation on their stability in a dynamic environment. The investigation of the radiolysis of a TBP/n-dodecane process solvent in contact with aqueous nitric acid has been performed. These studies were intended to confirm/optimize the operability of the test loop system. Additionally, these data are directly applicable to numerous other solvent extraction

  7. Summary Report on Gamma Radiolysis of TBP/n-dodecane in the Presence of Nitric Acid Using the Radiolysis/Hydrolysis Test Loop

    Design and installation has been completed for a state-of-the-art radiolysis/hydrolysis test loop system. The system is used to evaluate the effects of gamma radiolysis and acid hydrolysis on the stability and performance of solvent extraction process solvents. The test loop is comprised of two main sections; the solvent irradiation and hydrolysis loop and the solvent reconditioning loop. In the solvent irradiation and hydrolysis loop, aqueous and organic phases are mixed and circulated through a gamma irradiator until the desired absorbed dose is achieved. Irradiation of the mixed phases is more representative of actual conditions in a solvent extraction process. Additionally, the contact of the organic phase with the aqueous phase will subject the solvent components to hydrolysis. This hydrolysis can be accelerated by controlling the system at an elevated temperature. At defined intervals, the organic from the irradiation/hydrolysis loop will be transferred to the solvent reconditioning loop where the solvent is contacted with scrub, strip, and solvent wash solutions which simulate process flowsheet conditions. These two processes are repeated until the total desired dose is achieved. Since all viable solvent extraction components in an advanced fuel cycle must exhibit high radiolytic and hydrolytic stability, this test loop is not limited to any one solvent system but is applicable to all systems of interest. Also, the test loop is not limited to testing of process flowsheets. It is also a valuable tool in support of fundamental research on newly identified extractants/modifiers and the impact of gamma radiation on their stability in a dynamic environment. The investigation of the radiolysis of a TBP/n-dodecane process solvent in contact with aqueous nitric acid has been performed. These studies were intended to confirm/optimize the operability of the test loop system. Additionally, these data are directly applicable to numerous other solvent extraction

  8. Kinetics of enzymatic hydrolysis of methyl ricinoleate

    Neeharika, T. S.V.R.; Lokesh, P.; Prasanna Rani, K. N.; Prathap Kumar, T.; Prasad, R. B.N.

    2015-01-01

    Ricinoleic acid is an unsaturated hydroxy fatty acid that naturally occurs in castor oil in proportions of up to 85–90%. Ricinoleic acid is a potential raw material and finds several applications in coatings, lubricant formulations and pharmaceutical areas. Enzymatic hydrolysis of castor oil is preferred over conventional hydrolysis for the preparation of ricinoleic acid to avoid estolide formation. A kinetics analysis of the enzymatic hydrolysis of Methyl Ricinoleate in the presence of Candi...

  9. Hydrolysis of palm oil catalyzed by acid%棕榈油的酸催化水解工艺研究

    张玲玲; 王晖

    2015-01-01

    以棕榈油为原料进行常压酸催化水解工艺研究。考察了反应时间、反应温度、催化剂用量、油水质量比及乳化剂用量对棕榈油水解反应的影响,得出棕榈油一次酸催化水解的最佳反应条件:反应时间7 h,反应温度100℃,催化剂浓硫酸用量7.5%,油水质量比1∶1,乳化剂磺酸用量0.5%;在最佳反应条件下棕榈油水解产物酸值(KOH)为192.77 mg/g,水解率达到91.96%。并研究出一套循环水解的工艺流程,实现油脂水解产物的循环利用,提高了水相中甘油的含量。%The hydrolysis of palm oil catalyzed by acid was studied. The effects of reaction time,reaction temperature,catalyst dosage,mass ratio of oil to water and emulsifier dosage on the hydrolysis of palm oil were investigated. The optimal reaction conditions of palm oil hydrolysis were obtained as follows:reaction time 7 h,reaction temperature 100℃,mass ratio of oil to water 1∶1,dosage of sulfonic acid used as emul-sifier 0. 5% and catalyst( concentrated sulfonic acid) dosage 7. 5%. Under the optimal reaction condi-tions,the acid value of the hydrolysates was up to 192. 77 mgKOH/g and the hydrolysis rate of palm oil was 91. 96%. A circulated hydrolysis process was designed, then the recycling of hydrolysates was real-ized,and the content of glycerin in the aqueous phase increased.

  10. Hydrolysis of Cellulose by a Mesoporous Carbon-Fe2(SO4)3/γ-Fe2O3 Nanoparticle-Based Solid Acid Catalyst

    Yamaguchi, Daizo; Watanabe, Koki; Fukumi, Shinya

    2016-02-01

    Carbon-based solid acid catalysts have shown significant potential in a wide range of applications, and they have been successfully synthesized using simple processes. Magnetically separable mesoporous carbon composites also have enormous potential, especially in separation and adsorption technology. However, existing techniques have been unable to produce a magnetically separable mesoporous solid acid catalyst because no suitable precursors have been identified. Herein we describe a magnetically separable, mesoporous solid acid catalyst synthesized from a newly developed mesoporous carbon-γ-Fe2O3 nanoparticle composite. This material exhibits an equivalent acid density and catalytic activity in the hydrolysis of microcrystalline cellulose, to that of the cellulose-derived conventional catalyst. Since it is magnetically separable, this material can be readily recovered and reused, potentially reducing the environmental impact of industrial processes to which it is applied.

  11. Effects of organic acids on rice straw on supercritical hydrolysis%超临界下有机酸对稻秆水解糖化的影响

    李星纬; 巩桂芬; 李晓东

    2012-01-01

    With the organic acids ( formic acid, acetic acid, and propionic acid) as the catalyst, hydrolysis saccharification of rice straw in the batch reactor was investigated under the condition of the super- and sub-critical water. The reaction temperature, reaction time and solid-to-liquid ratio for reduction sugar yield were studied. Results showed that organic acid was helpful to the hydrolysis saccharification of straw. Reducing sugar yield could increase when adding organic acid. This trend was most evident when adding formic acid. With the extension of reaction time, reducing sugar yield could gradually decreased. In the appropriate range, reducing sugar production was much higher with the increasing of the solid-liquid ratio. The best conditions on straw hydrolysis saccharification in supercritical water from the experiment were as follows; formic acid concentration 3%, solid-to-liquid ratio 4:60, temperature 410 ℃ , and the reaction time 5 min. Under the conditions, the reducing sugar production reached the highest, 6. 65 g/L.%采用间歇式反应器在超临界条件下,以有机酸(甲酸、乙酸和丙酸)为催化剂对稻秆进行水解糖化研究,重点考察反应温度、反应时间、固液比对还原糖产率的影响.实验表明:有机酸的加入有利于稻秆的水解糖化,稻秆水解速率和还原糖产量都有所提高,这种趋势在加入甲酸时最为明显;随着反应时间的延长,还原糖产量会逐渐减少;适当提高固液比有助于增加还原糖产量.稻秆超临界水解糖化的最佳条件:甲酸体积分数3%、固液比4∶60(g/mL)、反应温度410℃、反应时间5 min,在此条件下,还原糖产量最高,达6.65 g/L.

  12. Use of surfactants in enzymatic hydrolysis of rice straw and lactic acid production from rice straw by simultaneous saccharification and fermentation

    Shichun Peng

    2007-01-01

    Full Text Available Rice straw (RS is one of the most abundant lignocellulosic waste by-products worldwide and provides an alternative substrate to produce useful chemicals such as bioethanol and lactic acid. However, higher enzyme loadings are needed to obtain a higher product yield, which makes the large-scale utilization economically difficult. The presence of non-ionic surfactants and poly(ethylene glycol (PEG during the enzymatic hydrolysis of lignocellulosics has been found to increase the conversion of cellulose into fermentable sugars. We have found that adding 0.2g g-1 substrate of polyoxyethylene(20 sorbitan monooleate (PSM or high-mass PEG increased the sugar yield by 22% and 12%, respectively, when enzyme loading was at 10FPU g-1 for 24h. PSM behaved better than PEG when different substrate concentrations, temperatures, and enzyme loadings were investigated. PSM provides an opportunity to reduce enzyme dosage while still keeping the same extent of hydrolysis. We also investigated the effect of PSM on the simultaneous saccharification and fermentation of pretreated RS to lactic acid. Results showed that addition of 0.7g L-1 PSM improved the lactic acid production by 24% compared to the reference without PSM addition at 72h.

  13. Super acid catalysed sequential hydrolysis/cycloisomerization of -(acetylenic)benzamides under microwave condition: Synthesis, antinociceptive and antiinflammatory activity of substituted isocoumarins

    Chandrasekaran Praveen; P Dheenkumar; P T Perumal

    2013-01-01

    Synthesis of isocoumarins and related compounds via triflic acid promoted hydrolysis/cyclization sequence of 2-(alkynyl)benzamides under microwave condition was achieved. The substrate scope of the reaction was broad to include not only aromatic but also polyaromatic and heteroaromatic motifs, thus highlighting the significance of this methodology. One-pot operation, short reaction time, good chemical yields and excellent regioselectivity are the advantages of this protocol. All the synthesized compounds were evaluated for their antinociceptive and antiinflammatory activities using in vivo rodent models.

  14. Isolation of pectin from pumpkin (Cucurbita moschata, L.) by acid hydrolysis;Isolamento de pectina de abobora (Cucurbita moschata, L.) por hidrolise acida

    Souza, Jose R.R.; Ricardo, Nagila M.P.S.; Paula, Regina C.M. de; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.b [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica. Lab. de Polimeros; Brito, Edy S. [EMBRAPA Agroindustria Tropical, Fortaleza, CE (Brazil)

    2009-07-01

    Pumpkin (Cucurbita moschata, L.) constitutes an excellent source of carotenoids, precursors of vitamin A. Besides, it also that constitutes also a great natural source of low-cost pectin. Pectin is a heterogeneous complex polysaccharide found in the primary cell wall of most plants and its effect on health is receiving increasing interest from the scientific community. In this work, high-methoxy pectin was obtained from pumpkin (Cucurbita moschata, L.) through the acid hydrolysis methodology. The pectin obtained was characterized by FTIR, NMR {sup 1}H, GPC and rheology. (author)

  15. Speciation analysis of seleno-amino acids in human serum: comparison of methods with and without protein hydrolysis

    Full text: This study presents the development of a reference method based on (reverse phase) HPLC-ICPMS for the determination of selenomethionine (SeMet) in human serum, following the enzymatic hydrolysis of selenoalbumin (SeAlb), a seleno-containing protein. Quantification of SeMet was carried out by species-specific isotope dilution (SSID); the assessment of the uncertainty budget and the steps contributing significantly to the overall uncertainty are addressed. The SSID HPLC-ICPMS procedure for the determination of SeMet in human serum was compared with a method relying on speciation analysis of intact selenoproteins (i.e. without hydrolysis), namely glutathione peroxidase, selenoprotein P and SeAlb, by means of a affinity-HPLC coupled to ICPMS. (author)

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

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

    2015-11-01

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

  17. Chemometrics-assisted Spectrofluorimetric Determination of Two Co-administered Drugs of Major Interaction, Methotrexate and Aspirin, in Human Urine Following Acid-induced Hydrolysis.

    Maher, Hadir M; Ragab, Marwa A A; El-Kimary, Eman I

    2015-01-01

    Methotrexate (MTX) is widely used to treat rheumatoid arthritis (RA), mostly along with non-steroidal anti-inflammatory drugs (NSAIDs), the most common of which is aspirin or acetyl salicylic acid (ASA). Since NSAIDs impair MTX clearance and increase its toxicity, it was necessary to develop a simple and reliable method for the monitoring of MTX levels in urine samples, when coadministered with ASA. The method was based on the spectrofluorimetric measurement of the acid-induced hydrolysis product of MTX, 4-amino-4-deoxy-10-methylpteroic acid (AMP), along with the strongly fluorescent salicylic acid (SA), a product of acid-induced hydrolysis of aspirin and its metabolites in urine. The overlapping emission spectra were resolved using the derivative method (D method). In addition, the corresponding derivative emission spectra were convoluted using discrete Fourier functions, 8-points sin xi polynomials, (D/FF method) for better elimination of interferences. Validation of the developed methods was carried out according to the ICH guidelines. Moreover, the data obtained using derivative and convoluted derivative spectra were treated using the non-parametric Theil's method (NP), compared with the least-squares parametric regression method (LSP). The results treated with Theil's method were more accurate and precise compared with LSP since the former is less affected by the outliers. This work offers the potential of both derivative and convolution using discrete Fourier functions in addition to the effectiveness of using the NP regression analysis of data. The high sensitivity obtained by the proposed methods was promising for measuring low concentration levels of the two drugs in urine samples. These methods were efficiently used to measure the drugs in human urine samples following their co-administration. PMID:26234512

  18. Acid Hydrolysis of Wheat Gluten Induces Formation of New Epitopes but Does Not Enhance Sensitizing Capacity by the Oral Route: A Study in “Gluten Free” Brown Norway Rats

    Kroghsbo, Stine; Andersen, Nanna Birch; Rasmussen, Tina Frid; Jacobsen, Susanne; Madsen, Charlotte Bernhard

    2014-01-01

    BackgroundAcid hydrolyzed wheat proteins (HWPs) are used in the food and cosmetic industry as emulsifiers. Cases of severe food allergic reactions caused by HWPs have been reported. Recent data suggest that these reactions are caused by HWPs produced by acid hydrolysis.ObjectivesTo examine the sensitizing capacity of gluten proteins per se when altered by acid or enzymatic hydrolysis relative to unmodified gluten in rats naïve to gluten.MethodsHigh IgE-responder Brown Norway (BN) rats bred on...

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

    Mayra Lizett González-Félix

    2014-09-01

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

  20. EFFECT OF INHIBITORS ON ENZYMATIC HYDROLYSIS AND SIMULTANEOUS SACCHARIFICATION FERMENTATION FOR LACTIC ACID PRODUCTION FROM STEAM EXPLOSION PRETREATED LESPEDEZA STALKS

    Yue Feng; Xiang Qi,; Hong-lei Jian,; Run-cang Sun; Jian-xin Jiang

    2012-01-01

    The effects on both cellulose conversion rate and lactic acid yield were studied by adding inhibitors, including formic acid, acetic acid, furfural, and vanillin into the hydrolysate of steam-pretreated Lespedeza stalks. The results suggest that formic acid has a significant influence on the enzyme activity and poisoned bacterial cells, resulting in the reduction of cellulose conversion rate and lactic acid yield by 21% and 16.4%, respectively. Acetic acid showed a strong inhibition on simult...

  1. HIDROLISIS ENZIMATIK MINYAK IKAN UNTUK PRODUKSI ASAM LEMAK OMEGA-3 MENGGUNAKAN LIPASE DARI Aspergillus niger [Enzymatic Hydrolysis of Fish Oil for Production of Omega-3 Fatty Acids Using Lipase Derived from Aspergillus niger

    Sapta Raharja*

    2011-06-01

    Full Text Available Fish oil is the source of important fatty-acid, especially polyunsaturated fatty acid (PUFA omega-3, such as eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. Lipase catalysis activity of Aspergillus niger is low when it is used in fish oil hydrolysis. The activity of the lipase can be increased by adding organic solvent such as hexane into the media. This research aimed to determine temperature, pH and amount of water which produce the highest degree of hydrolysis of fish oil in the presence of hexane. Correlation between the highest degree of hydrolysis and the amount of omega-3 fatty acid was also investigated. The variables used in this research were temperatures (25-65 oC, pH (5-9, and water addition (1-5 %v/v. The highest degree of enzymatic hydrolysis of fish oil in the media without hexane was 28.07 % that was reached at 45oC and pH 5. In the presence of hexane, the highest degree of hydrolysis was 75.12 % which was reached at 5% water addition, temperature 45oC, and pH 5. GC-MS analysis showed that omega-3 fatty acid content especially EPA and DHA increased along with increase in the degree of hydrolysis. Concentration of omega-3 fatty acid produced without hexane addition was 18.42 % with EPA amounted to 12,17% and DHA 0,86%. Meanwhile omega-3 fatty acid content in the presence of hexane reached 21.93 % with EPA amounted to 17.75 % and DHA 1.21 %.

  2. Characteristics of Bone Gelatin Tilapia (Oreochromis niloticus) Processed by Using Hydrolysis With Phosphoric Acid and Papain Enzyme

    Gugun Hidayat; Eko Nurcahya Dewi; Laras Rianingsih

    2016-01-01

    Phosphoric acid and papain enzyme able to hydrolyzing collagen from Tilapia into gelatin . The purpose of this research was to determine the best concentration of phosphoric acid and papain enzyme and to determine the physicochemical characteristic gelatin to from Tilapia fish bone which processed with phosphoric acid and papain enzyme. The first research phase was making bone gelatin tilapia using phosphoric acid at concentration of 4%, 5% and 6%, and the papain enzyme 0.5%, 1% a...

  3. A study of the acid-catalyzed hydrolysis of cellulose dissolved in ionic liquids and the factors influencing the dehydration of glucose and the formation of humins.

    Dee, Sean J; Bell, Alexis T

    2011-08-22

    An investigation was carried out into the hydrolysis of cellulose dissolved in 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]) and 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) catalyzed by mineral acids. Glucose, cellobiose, and 5-hydroxymethylfurfural (5-HMF) were observed as the primary reaction products. The initial rate of glucose formation was determined to be of first order in the concentrations of dissolved glucan and protons and of zero order in the concentration of water. The absence of a dependence on water concentration suggests that cleavage of the β-1,4-glycosidic linkages near chain ends is irreversible. The apparent activation energy for glucose formation is 96 kJ mol(-1). The absence of oligosaccharides longer than cellobiose suggests that cleavage of interior glycosidic bonds is reversible due to the slow diffusional separation of cleaved chains in the highly viscous glucan/ionic liquid solution. Progressive addition of water during the course of glucan hydrolysis inhibited the rate of glucose dehydration to 5-HMF and the formation of humins. The inhibition of glucose dehydration is attributed to stronger interaction of protons with water than the 2-OH atom of the pyranose ring of glucose, the critical step in the proposed mechanism for the formation of 5-HMF. The reduction in humin formation associated with water addition is ascribed to the lowered concentration of 5-HMF, since the formation of humins is suggested to proceed through the condensation polymerization of 5-HMF with glucose. PMID:21809450

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

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

    2015-06-01

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

  5. Enhancement of enzymatic hydrolysis of corn stover by γ-irradiation and combined solvent delignification/acid prehydrolysis

    Two pretreatment schemes were studied for their effect on the enhancement of soluble sugar production from corn stover by enzymatic hydrolysis. In the first scheme, prior to enzymic hydrolysis corn stover which was ground to pass a 1 mm screen was immersed in NaOH solution and exposed to gamma irradiation. The NaOH levels and radiation dosages were varied from 0 to 0.51 gNaOH/g corn stover and from 50 to 150 Mr, respectively. The combined residue and solubles were then hydrolyzed with a commercial cellulase (Onozuka) in 0.05 M citrate buffer at pH 4.6 and 390C for 48 hours. The highest sugar yield of 96% based on the total carbohydrate content of the original sample was obtained at 100 Mr and 0.06 gNaOH/g corn stover. In the second scheme, corn stover which was ground to pass a 0.35 mm screen was delignified with ethanol-water-NaOH. The ethanol-water mixture used contained 3 parts (by volume) of 95% ethanol and 4 g NaOH/L; substrate concentration was 5% (w/v). The delignification was carried out at 1400C for 1 hour. At these conditions, 65% of the lignin was removed while 90% of the carbohydrates remained insoluble. The delignified corn stover with an without treatment using 2% wt.% H2SO4 at 950C and 1 hour was then enzymically hydrolyzed with Novo Cellulclast at pH 4.8 and 500C for up to 48 hours. Factors that affect the overall sugar production are presented and discussed. In addition, the overall sugar yields for the two schemes are compared with other pretreatment schemes reported. (orig.)

  6. Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.

    Karthikeyan, Obulisamy Parthiba; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-01-01

    The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW. PMID:26512860

  7. Quantitative Prediction of Cell Wall Polysaccharide Composition in Grape (Vitis vinifera L.) and Apple (Malus domestica) Skins from Acid Hydrolysis Monosaccharide Profiles

    Arnous, Anis; Meyer, Anne S.

    2009-01-01

    On the basis of monosaccharide analysis after acid hydrolysis of fruit skin samples of three wine grape cultivars, Vitis vinifera L. Cabernet Sauvignon, Merlot, and Shiraz, and of two types of apple, Malus domestica Red Delicious and Golden Delicious, an iterative calculation method is reported for...... the quantitative allocation of plant cell wall monomers into relevant structural polysaccharide elements. By this method the relative molar distribution (mol %) of the different polysaccharides in the red wine grape skins was estimated as 57-62 mol % homogalacturonan, 6.0-14 mol % cellulose, 10-11 mol......-47% by weight of the skins (dry matter), the rest mainly being lignin. The predicted relative molar levels of the polysaccharide elements in the apple skins, which made up similar to 49-64% by weight of the skins (dry matter), appeared to be similar to those of the grape skins. The apple skins were...

  8. Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature

    Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L-1 NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

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

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

    2016-06-01

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

  10. The effect of the H2O/TEOS ratio on the structure of gels derived by the acid catalysed hydrolysis of tetraethoxysilane

    Silica gels were produced by the acid catalysed hydrolysis of tetraethoxysilane (TEOS) using H2O/TEOS ratios from 2 to 50. After heat treatment the structure of the gels was studied using nitrogen adsorption, small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and bulk density measurements. All the gels possessed microporosity in the region of 30 A or less. For H2O/TEOS = 25 and 50 the matrix density was found to be uniform, but for gels from solutions with H2O/TEOS = 2, 4 and 10, density fluctuations in the matrix were detected from a Porod analysis of the SAXS data. These results indicate that in high water content solutions, rearrangement of the polymeric chains leads to small densified particles, but for lower water content solutions, gelation results from the entanglement of linear chains leaving free volume on a molecular scale between the chains. (Author)

  11. Quantification of organic acids in particulate matter by coupling of thermally assisted hydrolysis and methylation with thermodesorption-gas chromatography-mass spectrometry.

    Beiner, K; Plewka, A; Haferkorn, S; Iinuma, Y; Engewald, W; Herrmann, H

    2009-09-18

    A quantitative method for the determination of organic acids in atmospheric particles is developed. The method couples a derivatisation step (thermally assisted hydrolysis and methylation) and a Curie point pyrolyser as a thermal desorption technique and gas chromatography-mass spectrometry (CPP-GC-MS). Among the reagents tested (tetramethylammonium hydroxide (TMAH), tetramethylammonium acetate (TMAAc) and phenyltrimethylammonium hydroxide (TMPAH)), the best performance was found using TMAAc as a derivatisation reagent for the reaction time of 4s at 510 degrees C as heating temperature. Calibration was performed for a series of fatty acids (FA), dicarboxylic acids (DCA) and terpenoic acids (TA) under these conditions. Coefficients of determination (R(2)) were between 0.94 and 0.98. Limits of detection (LOD) were in the nanogram-range between 0.1 and 3.6 ng. The method is applied on atmospheric particle samples to obtain the quantification reproducibility and quantification limits. Reproducibility was determined in terms of relative standard deviations (RSD) for ambient aerosol samples collected by a high-volume-sampler (HVS, RSD=6-45%, n=10) and a Berner impactor (BI, RSD=5-34%, n=10). Based on 24h sampling time the developed method enables quantification of all three classes of acids for both sampling techniques. Calibration data and presented volume concentrations are compared with literature data. A comparison with an off-line methylation-GC-MS using BF(3) as a derivatisation reagent and capillary electrophoresis coupled mass spectrometry (CE-MS) showed a good agreement. Minimal sample preparation is the main advantage of the developed method. Depending on the sensitivity requirements the present method can be a fast and simple alternative to GC-MS techniques with conventional sample preparation steps for semi-volatile organic acids. PMID:19679312

  12. Enteral Tube Feeding Nutritional Protein Hydrolysate Production Under Different Factors By Enzymatic Hydrolysis

    Nguyen ThiQuynhHoa; Nguyen Ngoc Phuong Diem; Nguyen Phuoc Minh; Dong ThiAnh Dao

    2015-01-01

    Abstract Hydrolysis of proteins involves the cleavage of peptide bonds to give peptides of varying sizes and amino acid composition. There are a number of types of hydrolysis enzymatic acid or alkali hydrolysis. Chemical hydrolysis is difficult to control and reduces the nutritional quality of products destroying L-form amino acids and producing toxic substances such as lysino-alanine. Enzymatic hydrolysis works without destructing amino acids and by avoiding the extreme temperatures and pH l...

  13. Identification of N-acylethanolamines in Dictyostelium discoideum and confirmation of their hydrolysis by fatty acid amide hydrolase[S

    Hayes, Alexander C.; Stupak, Jacek; Li, Jianjun; Cox, Andrew D.

    2013-01-01

    N-acylethanolamines (NAEs) are endogenous lipid-based signaling molecules best known for their role in the endocannabinoid system in mammals, but they are also known to play roles in signaling pathways in plants. The regulation of NAEs in vivo is partly accomplished by the enzyme fatty acid amide hydrolase (FAAH), which hydrolyses NAEs to ethanolamine and their corresponding fatty acid. Inhibition of FAAH has been shown to increase the levels of NAEs in vivo and to produce desirable phenotype...

  14. Hydrolysis and rearrangement of phthalamic acid derivatives and assessment of their potential as prodrug forms for amines

    Bundgaard, H; Steffansen, B

    1990-01-01

    various other N-alkyl and N-aryl substituted phthalamic acid derivatives were examined with the primary aim of assessing their degradation rate at physiological pH. Whereas the compounds I and II were indeed found to be easily degraded in neutral aqueous solutions, the degradation was not due to....... It is concluded that phthalamic acid derivatives are too stable chemically and enzymatically to be considered as prodrug forms for primary or secondary amines....

  15. Hydrolysis of uranium hexafluoride

    A literature survey is presented of uranium hexafluoride hydrolysis methods as the first step in UF6 conversion to UO2. Reviewed are early methods of hydrolysis, the hydrolysis by dry water vapour, the fluidized-bed method, and the liquid phase hydrolysis of UF6 gas. (J.P.)

  16. Carbachol induces a rapid and sustained hydrolysis of polyphosphoinositide in bovine tracheal smooth muscle measurements of the mass of polyphosphoinositides, 1,2-diacylglycerol, and phosphatidic acid

    Takuwa, Y.; Takuwa, N.; Rasmussen, H.

    1986-11-05

    The effects of carbachol on polyphosphoinositides and 1,2-diacylglycerol metabolism were investigated in bovine tracheal smooth muscle by measuring both lipid mass and the turnover of (/sup 3/H)inositol-labeled phosphoinositides. Carbachol induces a rapid reduction in the mass of phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 4-monophosphate and a rapid increase in the mass of 1,2-diacylglycerol and phosphatidic acid. These changes in lipid mass are sustained for at least 60 min. The level of phosphatidylinositol shows a delayed and progressive decrease during a 60-min period of carbachol stimulation. The addition of atropine reverses these responses completely. Carbachol stimulates a rapid loss in (/sup 3/H)inositol radioactivity from phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 4-monophosphate associated with production of (/sup 3/H)inositol trisphosphate. The carbachol-induced change in the mass of phosphoinositides and phosphatidic acid is not affected by removal of extracellular Ca/sup 2 +/ and does not appear to be secondary to an increase in intracellular Ca/sup 2 +/. These results indicate that carbachol causes phospholipase C-mediated polyphosphoinositide breakdown, resulting in the production of inositol trisphosphate and a sustained increase in the actual content of 1,2-diacylglycerol. These results strongly suggest that carbachol-induced contraction is mediated by the hydrolysis of polyphosphoinositides with the resulting generation of two messengers: inositol 1,4,5-trisphosphate and 1,2-diacylglycerol.

  17. Determination of the main impurities formed after acid hydrolysis of soybean extracts and the in vitro mutagenicity and genotoxicity studies of 5-ethoxymethyl-2-furfural.

    Nemitz, Marina C; Picada, Jaqueline N; da Silva, Juliana; Garcia, Ana Letícia H; Papke, Débora K M; Grivicich, Ivana; Steppe, Martin; von Poser, Gilsane L; Teixeira, Helder F

    2016-09-10

    Soybean acid hydrolyzed extracts are raw-materials widely used for manufacturing of pharmaceuticals and cosmetics products due to their high content of isoflavone aglycones. In the present study, the main sugar degradation products 5-hydroxymethyl-2-furfural (HMF) and 5-ethoxymethyl-2-furfural (EMF) were quantitatively determined after acid hydrolysis of extracts from different soybean cultivars by a validated liquid chromatography method. The furanic compounds determined in samples cover the range of 0.16-0.21mg/mL and 0.22-0.33mg/mL for HMF and EMF, respectively. Complementarily, due to the scarce literature regarding the EMF toxicology, this study also assessed the EMF mutagenicity by the Salmonella/microsome test and genotoxicity by the comet assay. The results revealed that EMF did not show mutagenicity at the range of 50-5000μg/plate in S. typhimurium strains TA98, TA97a, TA100, TA102 and TA1535, but induced DNA damage in HepG2 cells at non-cytotoxic doses of 0.1-1.3mg/mL, mainly by oxidative stress mechanisms. Based on literature of HMF genotoxicity, and considering the EMF genotoxicity results herein shown, purification procedures to remove these impurities from extracts are recommended during healthcare products development to ensure the security of the products. PMID:27475406

  18. SYNTHESIS OF CONDENSATION POLYMERS OF SALICYLIC ACID, FORMALDEHYDE AND ALKYL PRIMARY AMINES AND ITS APPLICATION AS A CATALYST FOR THE HYDROLYSIS OF p-NITROPHENYL ACETATE (PNPA) IN AQUEOUS SOLUTION

    HE Binglin(Ho Pinglum); HUANG Wenqiang

    1983-01-01

    As a model of serine hydrolase, the condensation polymers of salicylic acid, formaldehyde and methyl amine, n-propyl amine, n-hexyl amine or n-lauryl amine were prepared by polycondensation catalyzed by sulfuric acid. It was confirmed by potentiometric titration and infrared spectrum that the polymers containing tertiary amino group possess the structure which resembles the internal salt of amino acid in weak basic and weak acidic solution:[-OOC-OH-CH2-H+N-R-CH2-]n R=alkyl group The catalytic reaction of the above polymers for hydrolysis of active ester,p-nitrophenyl acetate (PNPA),was studied .It was found kinetically that the most efficient catalytic effect of polymer was composed of two salicylic acid groups and one tertiary amino group in the polymer chain.The rates of hydrolysis of PNPA increase with increasing of pH values and length of the alkyl group in the side chain of the polymers and the effect of the conformation of the polymer containing tertiary amino group in the buffer solution on the catalytic activity was also investigated. Hydrolysis of PNPA catalyzed by the polymer made of salicylic acid, formaldehyde and n-lauryl amine follows the simple Michaelis-Menten type mechanism . The kinetics parameters were determined as :Km 6.7×10-5 M and Vmax 2.07×10-7 M·min-1.

  19. Influence of metal ion hydrolysis on the determination of complex stability constants as shown by lanthanide complexes of α-amino acids

    The conventional potentiometric methods for the determination of stability constants disregard the hydrolysis as a competing reaction for complex formation of cations, such as lanthanides. Two different ways for recording the metal hydrolysis are shown. It is assumed on appropriate conditions that only the first complex is formed. (author)

  20. Statistical Optimization for Acid Hydrolysis of Microcrystalline Cellulose and Its Physiochemical Characterization by Using Metal Ion Catalyst

    Md. Ziaul Karim

    2014-10-01

    Full Text Available Hydrolyzing the amorphous region while keeping the crystalline region unaltered is the key technology for producing nanocellulose. This study investigated if the dissolution properties of the amorphous region of microcrystalline cellulose can be enhanced in the presence of Fe3+ salt in acidic medium. The process parameters, including temperature, time and the concentration of metal chloride catalyst (FeCl3, were optimized by using the response surface methodology (RSM. The experimental observation demonstrated that temperature and time play vital roles in hydrolyzing the amorphous sections of cellulose. This would yield hydrocellulose with higher crystallinity. The factors that were varied for the production of hydrocellulose were the temperature (x1, time (x2 and FeCl3 catalyst concentration (x3. Responses were measured in terms of percentage of crystallinity (y1 and the yield (y2 of the prepared hydrocellulose. Relevant mathematical models were developed. Analysis of variance (ANOVA was carried out to obtain the most significant factors influencing the responses of the percentage of crystallinity and yield. Under optimum conditions, the percentage of crystallinity and yield were 83.46% and 86.98% respectively, at 90.95 °C, 6 h, with a catalyst concentration of 1 M. The physiochemical characteristics of the prepared hydrocellulose were determined in terms of XRD, SEM, TGA and FTIR analyses. The addition of FeCl3 salt in acid hydrolyzing medium is a novel technique for substantially increasing crystallinity with a significant morphological change.

  1. Structural basis for the hydrolysis of ATP by a nucleotide binding subunit of an amino acid ABC transporter from Thermus thermophilus.

    Devi, Seenivasan Karthiga; Chichili, Vishnu Priyanka Reddy; Jeyakanthan, J; Velmurugan, D; Sivaraman, J

    2015-06-01

    ATP-binding cassette (ABC) transporters are a major family of small molecule transporter proteins, and their deregulation is associated with several diseases, including cancer. Here, we report the crystal structure of the nucleotide binding domain (NBD) of an amino acid ABC transporter from Thermus thermophilus (TTHA1159) in its apo form and as a complex with ADP along with functional studies. TTHA1159 is a putative arginine ABC transporter. The apo-TTHA1159 was crystallized in dimeric form, a hitherto unreported form of an apo NBD. Structural comparison of the apo and ADP-Mg(2+) complexes revealed that Phe14 of TTHA1159 undergoes a significant conformational change to accommodate ADP, and that the bound ADP interacts with the P-loop (Gly40-Thr45). Modeling of ATP-Mg(2+):TTHA1159 complex revealed that Gln86 and Glu164 are involved in water-mediated hydrogen bonding contacts and Asp163 in Mg(2+) ion-mediated hydrogen bonding contacts with the γ-phosphate of ATP, consistent with the findings of other ABC transporters. Mutational studies confirmed the necessity of each of these residues, and a comparison of the apo/ADP Mg(2+):TTHA1159 with its ATP-complex model suggests the likelihood of a key conformational change to the Gln86 side chain for ATP hydrolysis. PMID:25916755

  2. Ultrasound-assisted enzymatic hydrolysis for iodinated amino acid extraction from edible seaweed before reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry.

    Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2013-09-27

    The combination of reverse phase high performance liquid chromatography (RP-HPLC) with inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of monoiodotyrosine (MIT) and diiodotyrosine (DIT) in edible seaweed. A sample pre-treatment based on ultrasound assisted enzymatic hydrolysis was optimized for the extraction of these iodinated amino acids. Pancreatin was selected as the most adequate type of enzyme, and parameters affecting the extraction efficiency (pH, temperature, mass of enzyme and extraction time) were evaluated by univariate approaches. In addition, extractable inorganic iodine (iodide) was also quantified by anion exchange high performance liquid chromatography (AE-HPLC) coupled with ICP-MS. The proposed procedure offered limits of detection of 1.1 and 4.3ngg(-1) for MIT and DIT, respectively. Total iodine contents in seaweed, as well as total iodine in enzymatic digests were measured by ICP-MS after microwave assisted alkaline digestion with tetramethylamonium hydroxide (TMAH) for total iodine assessment, and also by treating the pancreatin extracts (extractable total iodine assessment). The optimized procedure was successfully applied to five different types of edible seaweed. The highest total iodine content, and also the highest iodide levels, was found in the brown seaweed Kombu (6646±45μgg(-1)). Regarding iodinated amino acids, Nori (a red seaweed) was by far the one with the highest amount of both species (42±3 and 0.41±0.024μgg(-1) for MIT and DIT, respectively). In general, MIT concentrations were much higher than the amounts of DIT, which suggests that iodine from iodinated proteins in seaweed is most likely bound in the form of MIT residues. PMID:23972456

  3. The use of superporous p(AAc (acrylic acid)) cryogels as support for Co and Ni nanoparticle preparation and as reactor in H2 production from sodium borohydride hydrolysis

    Here, we report for the first time the use of p(AAc (p(acrylic acid)) cryogel for in situ metal nanoparticle preparation, and their use as a superporous reactor for H2 generation from hydrolysis of NaBH4. Superporous p(AAc) cryogels and conventional hydrogels were prepared via free radical polymerization technique at low (−18 °C) and moderate (40 °C) temperatures, respectively. They were characterized by employing various methods such as swelling experiments, optical imaging, and SEM (Scanning Electron Microscopy) analysis. By reducing Co2+ and Ni2+ ions within p(AAc) cryogel and hydrogel matrices, the obtained Co and Ni metal nanoparticles were employed for H2 generation from NaBH4 hydrolysis. Various factors such as porosity, metal type, temperature, and the amount of sodium hydroxide were investigated to determine their effects on hydrogen generation from NaBH4 hydrolysis. Activation energy (Ea), enthalpy (ΔH#) and entropy (ΔS#) for NaBH4 hydrolysis by superporous p(AAc)-Co metal composites were 29.35 kJ mol−1,=36.85 kJ mol−1, and –157.88 J mol−1K−1, respectively. Cryogels showed better catalytic activity than conventional hydrogels in the hydrolysis reaction, and have a higher TOF (turnover frequency) value of 4.10 mol H2 (mol catalyst min)−1 compared to conventional hydrogels, due to its highly porous nature, short diffusion distances and fast response times. - Highlights: • Superporous cryogel supports for in situ metal nanoparticle preparation. • Fast H2 production from chemical hydride hydrolysis by cryogel-M composites. • Soft, superporous cryogel reactors for energy applications

  4. Basic Dynamics Research of Hemicellulose Hydrolysis by the Solid Acid%固体酸催化半纤维素水解的基础动力学研究

    项巍; 朱建良

    2011-01-01

    [目的]研究固体酸催化玉米桔秆半纤维素水解的基础动力学.[方法]单因素试验确定最佳固体酸种类、固固比、固液比,然后在以上最优条件下,综合考察反应温度和时间对半纤维素水解产率的影响.[结果]固体酸催化玉米秸秆半纤维素水解的最适反应条件:2号固体酸为催化剂,固固比1:1,固液比1:15,反应温度100℃,反应时间10 h.在该最适条件下,可溶性总糖浓度为34.7 g/L,半纤维素水解产率为93.8%.[结论]该研究为固体酸降解玉米秸秆工艺的优化和放大设计提供了基础动力学数据.%[Objective] The research aimed to study the basic dynamics of corn straw hemicellulose hydrolysis by the solid acid. [ Method ] The optimal solid acid class,solid-solid ratio,solid-liquid ratio were determined by the single factor experiment. Then,under the above best condition , the influences of reaction temperature and time on the hydrolysis rate of hemicellulose were comprehensively inspected. [ Result ] The optimal reaction condition of corn straw hemicellulose hydrolysis by the solid acid: number 2 solid acid as the catalyst, the solid-solid ratio was 1 : 1 ,the solid-liquid ratio was 1:15, the reaction temperature was 100 ℃ ,and the reaction time was 10 h. Under the optimal condition, the soluble total sugar concentration was 34.7 g/L,and the hydrolysis rate of hemicellulose was 93.8%. [ Conclusion] The research provided the basic dynamics data for the optimization and amplification design of com straw hydrolysis technics by the solid acid.

  5. 基于3,5-二硝基水杨酸法的水稻秸秆酶解工艺%Enzymatic Hydrolysis of Rice Straw Based on 3,5-dinitrosalicylic Acid Method

    李彬; 高翔; 孙倩; 陈坤杰

    2013-01-01

    For the purpose to improve the conversion rate of reducing sugar of rice straw, the cellulose was used in the enzymatic hydrolysis of rice straw. The content of reducing sugar was detected by 3,5-dinitrosalicylic acid method. The enzyme concentration, hydrolysis time and temperature were selected as inspecting factors. Meantime, comparisons of the enzymatic hydrolysis of rural rice straw with that of steam explosion pretreatment rice straw were made. The results showed when the cellulose weight content taking 10% of the dry rice straw, enzymatic hydrolysis time of 48 h and reaction temperature of 50℃ were ideal reaction conditions. The maximum reducing sugar yield of enzymatic hydrolysis original rice straw was 9.7% . The highest reducing sugar yield of enzymatic hydrolysis steam explosion rice straw was approximately 34. 3 %. Steam explosion pretreatment can obviously improve the production of reducing sugar of enzymatic hydrolysis rice straw, and at the same time accelerate the reaction rate.%为了提高汽爆水稻秸秆还原糖的转化率,采用纤维素酶对水稻秸秆进行酶解实验.还原糖的含量用3,5-二硝基水杨酸法进行测定.实验选用加酶量、酶解时长和反应温度作为考察因素,以原始水稻秸秆与蒸汽爆破预处理水稻秸秆作对比.结果表明纤维素酶用量占秸秆干物质质量的10%,酶解时长48 h,反应温度50℃是一个较为理想的反应条件;原始水稻秸秆最大酶解还原糖产量约为9.7%;蒸汽爆破水稻秸秆最大酶解还原糖产量约为34.3%;蒸汽爆破预处理能够显著提高水稻秸秆的酶解还原糖产量,并缩短酶解反应时间.

  6. Pretreatment of dried distillers grains with solubles by soaking in aqueous ammonia and subsequent enzymatic/dilute acid hydrolysis to produce fermentable sugars

    Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15% w/w NH4OH solution at a solid:liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied...

  7. Thioglycoside hydrolysis catalyzed by β-glucosidase

    Sweet almond β-glucosidase (EC 3.2.1.21) has been shown to have significant thioglycohydrolase activity. While the Km values for the S- and O-glycosides are similar, the kcat values are about 1000-times lower for the S-glycosides. Remarkably, the pH-profile for kcat/Km for hydrolysis of p-nitrophenyl thioglucoside (pNPSG) shows the identical dependence on a deprotonated carboxylate (pKa 4.5) and a protonated group (pKa 6.7) as does the pH-profile for hydrolysis of the corresponding O-glycoside. Not surprisingly, in spite of the requirement for the presence of this protonated group in catalytically active β-glucosidase, thioglucoside hydrolysis does not involve general acid catalysis. There is no solvent kinetic isotope effect on the enzyme-catalyzed hydrolysis of pNPSG

  8. Novel double prodrugs of the iron chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED): Synthesis, characterization, and investigation of activation by chemical hydrolysis and oxidation.

    Thiele, Nikki A; Abboud, Khalil A; Sloan, Kenneth B

    2016-08-01

    The development of iron chelators suitable for the chronic treatment of diseases where iron accumulation and subsequent oxidative stress are implicated in disease pathogenesis is an active area of research. The clinical use of the strong chelator N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) and its alkyl ester prodrugs has been hindered by poor oral bioavailability and lack of conversion to the parent chelator, respectively. Here, we present novel double prodrugs of HBED that have the carboxylate and phenolate donors of HBED masked with carboxylate esters and boronic acids/esters, respectively. These double prodrugs were successfully synthesized as free bases (7a-f) or as dimesylate salts (8a-c,e), and were characterized by (1)H, (13)C, and (11)B NMR; MP; MS; and elemental analysis. The crystal structure of 8a was solved. Three of the double prodrugs (8a-c) were selected for further investigation into their abilities to convert to HBED by stepwise hydrolysis and H2O2 oxidation. The serial hydrolysis of the pinacol and methyl esters of N,N'-bis(2-boronic acid pinacol ester benzyl)ethylenediamine-N,N'-diacetic acid methyl ester dimesylate (8a) was verified by LC-MS. The macro half-lives for the hydrolyses of 8a-c, measured by UV, ranged from 3.8 to 26.3 h at 37 °C in pH 7.5 phosphate buffer containing 50% MeOH. 9, the product of hydrolysis of 8a-c and the intermediate in the conversion pathway, showed little-to-no affinity for iron or copper in UV competition experiments. 9 underwent a serial oxidative deboronation by H2O2 in N-methylmorpholine buffer to generate HBED (k = 10.3 M(-1) min(-1)). The requirement of this second step, oxidation, before conversion to the active chelator is complete may confer site specificity when only localized iron chelation is needed. Overall, these results provide proof of principle for the activation of the double prodrugs by chemical hydrolysis and H2O2 oxidation, and merit further investigation into the

  9. HYDROLYSIS OF PAPER-DISHWARE WASTES BY CELLULASE

    Jie Lu; Shulan Shi; Runan Yang; Fuzheng Liang

    2004-01-01

    The optimum conditions of hydrolysis of cellulosic wastes by cellulase were studied. The results show that the optimum conditions of sulfuric acid pretreatment were sulfuric acid consistency 0.3M,pretreatment temperature 100℃, pretreatment time 4hours. After sulfuric acid pretreatment, the optimum conditions of hydrolysis by cellulase were enzymatic temperature 50℃ ,enzymatic time 48hours,pH4.8,the charge of cellulase 100IU/g and the substraste consistency 60g/l. Meanwhile this paper studies that the structural change of cellulose during sulfuric acid pretreatment and cellulase hydrolysis by analyzing the infrared spectra.

  10. HYDROLYSIS OF PAPER-DISHWARE WASTES BY CELLULASE

    JieLu; ShulanShi; RunanYang; FuzhengLiang

    2004-01-01

    The optimum conditions of hydrolysis of cellulosic wastes by cellulase were studied. The results show that the optimum conditions of sulfuric acid pretreatment were sulfuric acid consistency 0.3M, pretreatment temperature 100℃, pretreatment time 4hours. After sulfuric acid pretreatment, the optimum conditions of hydrolysis by cellulase were enzymatic temperature 50℃, enzymatic time 48hours,pH4.8,the charge of cellulase 100IU/g and the substraste consistency 60g/l. Meanwhile this paper studies that the structural change of cellulose during sulfuric acid pretreatment and cellulase hydrolysis by analyzing the infrared spectra.