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Sample records for acid hydrolysis methylation

  1. Acid hydrolysis of cellulose to yield glucose

    DOEpatents

    Tsao, George T.; Ladisch, Michael R.; Bose, Arindam

    1979-01-01

    A process to yield glucose from cellulose through acid hydrolysis. Cellulose is recovered from cellulosic materials, preferably by pretreating the cellulosic materials by dissolving the cellulosic materials in Cadoxen or a chelating metal caustic swelling solvent and then precipitating the cellulose therefrom. Hydrolysis is accomplished using an acid, preferably dilute sulfuric acid, and the glucose is yielded substantially without side products. Lignin may be removed either before or after hydrolysis.

  2. Acid Hydrolysis of Trioxalatocobaltate (III) Ion

    ERIC Educational Resources Information Center

    Wiggans, P. W.

    1975-01-01

    Describes an investigation involving acid hydrolysis and using both volumetric and kinetic techniques. Presents examples of the determination of the rate constant and its variation with temperature. (GS)

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

    PubMed

    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.

  4. Optimization of dilute acid hydrolysis of Enteromorpha

    NASA Astrophysics Data System (ADS)

    Feng, Dawei; Liu, Haiyan; Li, Fuchao; Jiang, Peng; Qin, Song

    2011-11-01

    Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydrolysis of Enteromorpha using acids that are typically used to hydrolyze biomass: H2SO4, HCl, H3PO4 and C4H4O4 (maleic acid). 5%(w/w) Enteromorpha biomass was treated for different times (30, 60, and 90 min) and with different acid concentrations (0.6, 1.0, 1.4, 1.8, and 2.2%, w/w) at 121°C. H2SO4 was the most effective acid in this experiment. We then analyzed the hydrolysis process in H2SO4 in detail using high performance liquid chromatography. At a sulfuric acid concentration of 1.8% and treatment time of 60 min, the yield of ethanol fermentable sugars (glucose and xylose) was high, (230.5 mg/g dry biomass, comprising 175.2 mg/g glucose and 55.3 mg/g xylose), with 48.6% of total reducing sugars being ethanol fermentable. Therefore, Enteromorpha could be a good candidate for production of fuel ethanol. In future work, the effects of temperature and biomass concentration on hydrolysis, and also the fermentation of the hydrolysates to ethanol fuel should be focused on.

  5. Extraterrestrial material analysis: loss of amino acids during liquid-phase acid hydrolysis

    NASA Astrophysics Data System (ADS)

    Buch, Arnaud; Brault, Amaury; Szopa, Cyril; Freissinet, Caroline

    2015-04-01

    Searching for building blocks of life in extraterrestrial material is a way to learn more about how life could have appeared on Earth. With this aim, liquid-phase acid hydrolysis has been used, since at least 1970 , in order to extract amino acids and other organic molecules from extraterrestrial materials (e.g. meteorites, lunar fines) or Earth analogues (e.g. Atacama desert soil). This procedure involves drastic conditions such as heating samples in 6N HCl for 24 h, either under inert atmosphere/vacuum, or air. Analysis of the hydrolyzed part of the sample should give its total (free plus bound) amino acid content. The present work deals with the influence of the 6N HCl hydrolysis on amino acid degradation. Our experiments have been performed on a standard solution of 17 amino acids. After liquid-phase acid hydrolysis (6N HCl) under argon atmosphere (24 h at 100°C), the liquid phase was evaporated and the dry residue was derivatized with N-Methyl-N-(t-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and dimethylformamide (DMF), followed by gas chromatography-mass spectrometry analysis. After comparison with derivatized amino acids from the standard solution, a significant reduction of the chromatographic peak areas was observed for most of the amino acids after liquid-phase acid hydrolysis. Furthermore, the same loss pattern was observed when the amino acids were exposed to cold 6N HCl for a short amount of time. The least affected amino acid, i.e. glycine, was found to be 73,93% percent less abundant compared to the non-hydrolyzed standard, while the most affected, i.e. histidine, was not found in the chromatograms after hydrolysis. Our experiments thereby indicate that liquid-phase acid hydrolysis, even under inert atmosphere, leads to a partial or total loss of all of the 17 amino acids present in the standard solution, and that a quick cold contact with 6N HCl is sufficient to lead to a loss of amino acids. Therefore, in the literature, the reported increase

  6. Acid-functionalized nanoparticles for biomass hydrolysis

    NASA Astrophysics Data System (ADS)

    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. Enhanced functional properties of tannic acid after thermal hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal hydrolysis processing of fresh tannic acid was carried out in a closed reactor at four different temperatures (65, 100, 150 and 200°C). Pressures reached in the system were 1.3 and 4.8 MPa at 150 and 200°C, respectively. Hydrolysis products (gallic acid and pyrogallol) were separated and qua...

  8. Isopropyl methyl phosphonic acid (IMPA)

    Integrated Risk Information System (IRIS)

    Isopropyl methyl phosphonic acid ( IMPA ) ; CASRN 1832 - 54 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assess

  9. ESTIMATION OF CARBOXYLIC ACID ESTER HYDROLYSIS RATE CONSTANTS

    EPA Science Inventory

    SPARC chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid esters from molecular structure. The energy differences between the initial state and the transition state for a molecule of interest are factored into internal and external...

  10. Degradation of Opioids and Opiates During Acid Hydrolysis Leads to Reduced Recovery Compared to Enzymatic Hydrolysis.

    PubMed

    Sitasuwan, Pongkwan; Melendez, Cathleen; Marinova, Margarita; Mastrianni, Kaylee R; Darragh, Alicia; Ryan, Emily; Lee, L Andrew

    2016-10-01

    Drug monitoring laboratories utilize a hydrolysis process to liberate the opiates from their glucuronide conjugates to facilitate their detection by tandem mass spectrometry (MS). Both acid and enzyme hydrolysis have been reported as viable methods, with the former as a more effective process for recovering codeine-6-glucuronide and morphine-6-glucuronide. Here, we report concerns with acid-catalyzed hydrolysis of opioids, including a significant loss of analytes and conversions of oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine. The acid-catalyzed reaction was monitored in neat water and patient urine samples by liquid chromatography-time-of-flight and tandem MS. These side reactions with acid hydrolysis may limit accurate quantitation due to loss of analytes, possibly lead to false positives, and poorly correlate with pharmacogenetic profiles, as cytochrome P450 enzyme (CYP2D6) is often involved with oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine conversions. Enzymatic hydrolysis process using the purified, genetically engineered β-glucuronidase (IMCSzyme(®)) addresses many of these concerns and demonstrates accurate quantitation and high recoveries for oxycodone, hydrocodone, oxymorphone and hydromorphone.

  11. Acid hydrolysis of sugarcane bagasse for lactic acid production.

    PubMed

    Laopaiboon, Pattana; Thani, Arthit; Leelavatcharamas, Vichean; Laopaiboon, Lakkana

    2010-02-01

    In order to use sugarcane bagasse as a substrate for lactic acid production, optimum conditions for acid hydrolysis of the bagasse were investigated. After lignin extraction, the conditions were varied in terms of hydrochloric (HCl) or sulfuric (H(2)SO(4)) concentration (0.5-5%, v/v), reaction time (1-5h) and incubation temperature (90-120 degrees C). The maximum catalytic efficiency (E) was 10.85 under the conditions of 0.5% of HCl at 100 degrees C for 5h, which the main components (in gl(-1)) in the hydrolysate were glucose, 1.50; xylose, 22.59; arabinose, 1.29; acetic acid, 0.15 and furfural, 1.19. To increase yield of lactic acid production from the hydrolysate by Lactococcus lactis IO-1, the hydrolysate was detoxified through amberlite and supplemented with 7 g l(-1) of xylose and 7 g l(-1) of yeast extract. The main products (in gl(-1)) of the fermentation were lactic acid, 10.85; acetic acid, 7.87; formic acid, 6.04 and ethanol, 5.24.

  12. Hydrolysis mechanism of methyl parathion evidenced by Q-Exactive mass spectrometry.

    PubMed

    Liu, Yuan; Zhang, Caixiang; Liao, Xiaoping; Luo, Yinwen; Wu, Sisi; Wang, Jianwei

    2015-12-01

    Organophosphorus pesticides (OPPs), a kind of widely used pesticides, are currently attracting great attention due to their adverse effects on human central nervous systems, particularly in children. Although the hydrolysis behavior of OPPs has been studied well, its hydrolysis mechanism remained controversial, especially at various pH conditions, partly due to their relatively complex structures and abundant moieties that were prone to be attacked by nucleophiles. The Q-Exactive mass spectrometer, part of those hybrid high-resolution mass spectrometers (HRMS), was used to determine hydrolysis products of methyl parathion (MP), a kind of OPPs in situ buffer aqueous solution with pH ranging from 1 to 13 in this study. Most of the complex hydrolysis products of MP were identified due to the high sensitivity and accuracy of HRMS. The results demonstrated that the hydrolysis rate and pathway of MP were strong pH dependent. With the increase of pH, the hydrolysis rate of MP increased, and two different reaction mechanisms were identified: SN (2)@P pathway dominated the hydrolysis process at high pH (e.g., pH ≥ 11) while SN (2)@C was the main behavior at low pH (e.g., pH ≤ 9). This study helps understand the hydrolysis mechanism of OPPs at various pH and extends the use of Q-Exactive mass spectrometry in identifying organic pollutants and their degradation products in environmental matrices.

  13. Investigation of Unexpected Reaction Intermediates in the Alkaline Hydrolysis of Methyl 3,5-Dinitrobenzoate

    ERIC Educational Resources Information Center

    Silva, Clesia C.; Silva, Ricardo O.; Navarro, Daniela M. A. F.; Navarro, Marcelo

    2009-01-01

    An experimental project aimed at identifying stable reaction intermediates is described. Initially, the studied reaction appears to involve the simple hydrolysis, by aqueous sodium hydroxide, of methyl 3,5-dinitrobenzoate dissolved in dimethyl sulfoxide. On mixing the substrates, however, the reaction mixture unexpectedly turns an intense red in…

  14. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. II. ACID AND GENERAL BASE CATALYZED HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate acid and neutral hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition states of a ...

  15. Hydrolysis of aspartic acid phosphoramidate nucleotides: a comparative quantum chemical study.

    PubMed

    Michielssens, Servaas; Tien Trung, Nguyen; Froeyen, Matheus; Herdewijn, Piet; Tho Nguyen, Minh; Ceulemans, Arnout

    2009-09-07

    L-Aspartic acid has recently been found to be a good leaving group during HIV reverse transcriptase catalyzed incorporation of deoxyadenosine monophosphate (dAMP) in DNA. This showed that L-Asp is a good mimic for the pyrophosphate moiety of deoxyadenosine triphosphate. The present work explores the thermochemistry and mechanism for hydrolysis of several models for L-aspartic-dAMP using B3LYP/DGDZVP, MP2/6-311++G** and G3MP2 level of theory. The effect of the new compound is gradually investigated: starting from a simple methyl amine leaving group up to the aspartic acid leaving group. The enzymatic environment was mimicked by involving two Mg(2+) ions and some important active site residues in the reaction. All reactions are compared to the corresponding O-coupled leaving group, which is methanol for methyl amine and malic acid for aspartic acid. With methyl amine as a leaving group a tautomeric associative or tautomeric dissociative mechanism is preferred and the barrier is lower than the comparable mechanism with methanol as a leaving group. The calculations on the aspartic acid in the enzymatic environment show that qualitatively the mechanism is the same as for triphosphate but the barrier for hydrolysis by the associative mechanism is higher for L-aspartic-dAMP than for L-malic-dAMP and pyrophosphate.

  16. Validation of lignocellulosic biomass carbohydrates determination via acid hydrolysis.

    PubMed

    Zhou, Shengfei; Runge, Troy M

    2014-11-04

    This work studied the two-step acid hydrolysis for determining carbohydrates in lignocellulosic biomass. Estimation of sugar loss based on acid hydrolyzed sugar standards or analysis of sugar derivatives was investigated. Four model substrates (starch, holocellulose, filter paper and cotton) and three levels of acid/material ratios (7.8, 10.3 and 15.4, v/w) were studied to demonstrate the range of test artifacts. The method for carbohydrates estimation based on acid hydrolyzed sugar standards having the most satisfactory carbohydrate recovery and relative standard deviation. Raw material and the acid/material ratio both had significant effect on carbohydrate hydrolysis, suggesting the acid to have impacts beyond a catalyst in the hydrolysis. Following optimal procedures, we were able to reach a carbohydrate recovery of 96% with a relative standard deviation less than 3%. The carbohydrates recovery lower than 100% was likely due to the incomplete hydrolysis of substrates, which was supported by scanning electron microscope (SEM) images.

  17. Acid hydrolysis of cellulose in zinc chloride solution

    SciTech Connect

    Cao, N.J.; Xu, Q.; Chen, L.F.

    1995-12-31

    The efficient conversion of cellulosic materials to ethanol has been hindered by the low yield of sugars, the high energy consumption in pretreatment processes, and the difficulty of recycling the pre-treatment agents. Zinc chloride may provide an alternative for pre-treating biomass prior to the hydrolysis of cellulose. The formation of a zinc-cellulose complex during the pretreatment of cellulose improves the yield of glucose in both the enzymatic and acid hydrolysis of cellulose. Low-temperature acid hydrolysis of cellulose in zinc chloride solution is carried out in two stages, a liquefaction stage and a saccharification stage. Because of the formation of zinc-cellulose complex in the first stage, the required amount of acid in the second stage has been decreased significantly. In 67% zinc chloride solution, a 99.5% yield of soluble sugars has been obtained at 70{degrees}C and 0.5M acid concentration. The ratio of zinc chloride to cellulose has been reduced from 4.5 to 1.5, and the yield of soluble sugars is kept above 80%. The rate of hydrolysis is affected by the ratio of zinc chloride to cellulose, acid concentration, and temperature.

  18. Role of bifidobacteria in the hydrolysis of chlorogenic acid.

    PubMed

    Raimondi, Stefano; Anighoro, Andrew; Quartieri, Andrea; Amaretti, Alberto; Tomás-Barberán, Francisco A; Rastelli, Giulio; Rossi, Maddalena

    2015-02-01

    This study aimed to explore the capability of potentially probiotic bifidobacteria to hydrolyze chlorogenic acid into caffeic acid (CA), and to recognize the enzymes involved in this reaction. Bifidobacterium strains belonging to eight species occurring in the human gut were screened. The hydrolysis seemed peculiar of Bifidobacterium animalis, whereas the other species failed to release CA. Intracellular feruloyl esterase activity capable of hydrolyzing chlorogenic acid was detected only in B. animalis. In silico research among bifidobacteria esterases identified Balat_0669 as the cytosolic enzyme likely responsible of CA release in B. animalis. Comparative modeling of Balat_0669 and molecular docking studies support its role in chlorogenic acid hydrolysis. Expression, purification, and functional characterization of Balat_0669 in Escherichia coli were obtained as further validation. A possible role of B. animalis in the activation of hydroxycinnamic acids was demonstrated and new perspectives were opened in the development of new probiotics, specifically selected for the enhanced bioconversion of phytochemicals into bioactive compounds.

  19. [Transferase activity of horse blood serum cholinesterase at hydrolysis of 1-methyl-8-acetoxychinolium iodide in the presence of aliphatic alcohols].

    PubMed

    Basova, N E; Kormilitsyn, B N; Perchenok, A Yu; Rozengart, E V; Saakov, V S; Suvorov, A A

    2014-01-01

    To check whether the horse blood serum butyrylcholinesterase expresses transferase activity at the complex ester hydrolysis in the presense of several low-molecular aliphatic alcohols, a study was performed with aid of the chromogenic substrate 1-methyl-8-acetoxychinolium whose phenolic hydrolysis product absorbs intensively at 445 nm, whereas the initial ester in this specter area practically does not absorb. This allowed measuring simultaneously the products of accumulation of both products of enzymatic hydrolysis: of acetic acid by the potentiometric, while of phenol--by the photometric method. Rates of formation of both products of enzymatic hydrolysis are practically equal in experiments with all studied alcohols. This indicates that horse blood serum butyrylcholinesterase under these experimental conditions does not catalize transfer of acetyl residue to the studied aliphatic alcohols, i. e. does not have transefase activity.

  20. Ethanol production with dilute acid hydrolysis using partially dried lignocellulosics

    DOEpatents

    Nguyen, Quang A.; Keller, Fred A.; Tucker, Melvin P.

    2003-12-09

    A process of converting lignocellulosic biomass to ethanol, comprising hydrolyzing lignocellulosic materials by subjecting dried lignocellulosic material in a reactor to a catalyst comprised of a dilute solution of a strong acid and a metal salt to lower the activation energy (i.e., the temperature) of cellulose hydrolysis and ultimately obtain higher sugar yields.

  1. Artefact formation during acid hydrolysis of saponins from Medicago spp.

    PubMed

    Tava, Aldo; Biazzi, Elisa; Mella, Mariella; Quadrelli, Paolo; Avato, Pinarosa

    2017-02-28

    Artefact compounds obtained during acid hydrolysis of saponins from Medicago spp. (Fabaceae), have been monitored and evaluated by GC-FID. Their identification has been performed by GC-MS and (1)H and (13)C NMR. Saponins with different substituents on the triterpenic pentacyclic aglycones were considered, and their hydrolysis products were detected and quantified during 10 h of time course reaction. From soyasapogenol B glycoside the well known soyasapogenols B, C, D and F were obtained together with a previously undescribed sapogenol artefact identified as 3β,22β,24-trihydroxyolean-18(19)-en and named soyasapogenol H. From a zanhic acid saponin two major artefact compounds identified as 2β,3β,16α-trihydroxyolean-13(18)-en-23,28-dioic acid and 2β,3β,16α-trihydroxyolean-28,13β-olide-23-oic acid were obtained, together with some zanhic acid. Other compounds, detected in very small amount in the reaction mixture, were also tentatively identified based on their GC-MS and UV spectra. The other most characteristic saponins in Medicago spp., hederagenin, bayogenin and medicagenic acid glycosides, under acidic condition of hydrolysis, released instead the correspondent aglycones and generated a negligible amount of artefacts. Nature of artefacts and mechanism of their formation, involving a stable tertiary carbocation, is here proposed and discussed for the first time.

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

    PubMed

    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.

  3. Carbon-based strong solid acid for cornstarch hydrolysis

    SciTech Connect

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

    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.

  4. Acid hydrolysis of sweet potato for ethanol production

    SciTech Connect

    Kim, K.; Hamdy, M.K.

    1985-01-01

    Studies were conducted to establish optimal conditions for the acid hydrolysis of sweet potato for maximal ethanol yield. The starch contents of two sweet potato cultivars (Georgia Red and TG-4), based on fresh weight, were 21.1 +/- 0.6% and 27.5 +/- 1.6%, respectively. The results of acid hydrolysis experiments showed the following: (1) both hydrolysis rate and hydroxymethylfurfural (HMF) concentration were a function of HCL concentration, temperature, and time; (2) the reducing sugars were rapidly formed with elevated concentrations of HCl and temperature, but also destroyed quickly; and (3) HMF concentration increased significantly with the concentration of HCl, temperature, and hydrolysis time. Maximum reducing sugar value of 84.2 DE and 0.056% HMF (based on wet weight) was achieved after heating 8% SPS for 15 min in 1N HCl at 110/sup 0/C. Degraded 8% SPS (1N HCl, 97/sup 0/C for 20 min or 110/sup 0/C for 10 min) was utilized as substrate for ethanol fermentation and 3.8% ethanol (v/v) was produced from 1400 mL fermented wort. This is equal to 41.6 g ethanol (200 proof) from 400 g of fresh sweet potato tuber (Georgia Red) or an ethanol yield potential of 431 gal of 200-proof ethanol/acre (from 500 bushel tubers/acre).

  5. Separating Octadecyltrimethoxysilane Hydrolysis and Condensation at the Air/Water Interface through Addition of Methyl Stearate

    PubMed Central

    Britt, David W.; Hlady, Vladimir

    2012-01-01

    The hydrolysis and condensation of octadecyltrimethoxysilane (OTMS) at the air/water interface were monitored through molecular area changes at a constant surface pressure of 10 mN/m. The onset of condensation was delayed through the addition of methyl stearate (SME) acting as an inert filler molecule. In the absence of SME, complete gelation of OTMS required 30 h, during which time OTMS condensation occurred concomitantly with hydrolysis. In the presence of SME, the OTMS monolayer gelation rate increased in proportion to the amount of SME present. A 1:6 OTMS:SME molar ratio resulted in monolayer gelation within 30 min, suggesting completion of monomer hydrolysis prior to condensation. These findings indicate that lability of OTMS to hydrolysis at the air/water interface is governed by steric and conformational constraints at the silicon atom site, with monomeric OTMS being much more reactive than oligomeric OTMS. Fluorescence microscope images demonstrated that the OTMS condensed domain size also decreased with increasing SME concentrations, further implicating SME’s role as an inert filler. PMID:25132807

  6. Kinetic study of sulphuric acid hydrolysis of protein feathers.

    PubMed

    Ben Hamad Bouhamed, Sana; Kechaou, Nabil

    2017-02-28

    Poultry feather keratin is the most important by-product from the poultry industry due to its abundance. Different methods have been still applied to process this by-product such as enzymatic hydrolysis which is expensive and inapplicable at the industrial level. This paper presents a study of acid hydrolysis of poultry feathers using different types of acids, sulphuric acid concentration, different temperatures and solid to liquid ratio to obtain a liquid product rich in peptides. The feathers analysis revealed a crude protein content of 88.83%. A maximum peptides production of 676 mg/g was reached using sulphuric acid, 1 molar acid concentration and 50 g/l solid to liquid ratio at a temperature of 90 °C after 300 min. A reaction scheme for protein aggregation and decomposition to polypeptides and amino acids was proposed and a kinetic model for peptides production was developed. The proposed kinetic model proved to be well adapted to the experimental data with R (2) = 0.99.

  7. Production of polymalic acid and malic acid by Aureobasidium pullulans fermentation and acid hydrolysis.

    PubMed

    Zou, Xiang; Zhou, Yipin; Yang, Shang-Tian

    2013-08-01

    Malic acid is a dicarboxylic acid widely used in the food industry and also a potential C4 platform chemical that can be produced from biomass. However, microbial fermentation for direct malic acid production is limited by low product yield, titer, and productivity due to end-product inhibition. In this work, a novel process for malic acid production from polymalic acid (PMA) fermentation followed by acid hydrolysis was developed. First, a PMA-producing Aureobasidium pullulans strain ZX-10 was screened and isolated. This microbe produced PMA as the major fermentation product at a high-titer equivalent to 87.6 g/L of malic acid and high-productivity of 0.61 g/L h in free-cell fermentation in a stirred-tank bioreactor. Fed-batch fermentations with cells immobilized in a fibrous-bed bioreactor (FBB) achieved the highest product titer of 144.2 g/L and productivity of 0.74 g/L h. The fermentation produced PMA was purified by adsorption with IRA-900 anion-exchange resins, achieving a ∼100% purity and a high recovery rate of 84%. Pure malic acid was then produced from PMA by hydrolysis with 2 M sulfuric acid at 85°C, which followed the first-order reaction kinetics. This process provides an efficient and economical way for PMA and malic acid production, and is promising for industrial application.

  8. Kinetic analysis of the hydrolysis of methyl parathion using citrate-stabilized 10 nm gold nanoparticles.

    PubMed

    Nita, Rafaela; Trammell, Scott A; Ellis, Gregory A; Moore, Martin H; Soto, Carissa M; Leary, Dagmar H; Fontana, Jake; Talebzadeh, Somayeh F; Knight, D Andrew

    2016-02-01

    "Ligand-free" citrate-stabilized 10 nm gold nanoparticles (AuNPs) promote the hydrolysis of the thiophosphate ester methyl parathion (MeP) on the surface of gold as a function of pH and two temperature values. At 50 °C, the active surface gold atoms show catalytic turnover ∼4 times after 8 h and little turnover of gold surface atoms at 25 °C with only 40% of the total atoms being active. From Michaelis-Menten analysis, k(cat) increases between pH 8 and 9 and decreases above pH 9. A global analysis of the spectral changes confirmed the stoichiometric reaction at 25 °C and the catalytic reaction at 50 °C and mass spectrometry confirmed the identity of p-nitrophenolate (PNP) product. Additional decomposition pathways involving oxidation and hydrolysis independent of the formation of PNP were also seen at 50 °C for both catalyzed and un-catalyzed reactions. This work represents the first kinetic analysis of ligand-free AuNP catalyzed hydrolysis of a thiophosphate ester.

  9. Inhibition of N-methyl-N-nitrosourea-induced mutagenicity and DNA methylation by ellagic acid.

    PubMed Central

    Dixit, R; Gold, B

    1986-01-01

    Ellagic acid, a naturally occurring plant phenol, inhibits the activity of the direct-acting mutagen N-methyl-N-nitrosourea (MeNU) in Salmonella typhimurium TA100. Ellagic acid at 0.10, 0.25, 0.50, and 1.00 mM inhibited the mutagenicity of MeNU (0.40 mM) by 3%, 13%, 45%, and 60%, respectively. Ellagic acid (3 mM) also inhibited the mutagenic activity of N,N-dimethylnitrosamine (25-200 mM) in the presence of pyrazole-induced rat liver fraction S-9. The effect of ellagic acid on DNA methylation was studied by incubating 0, 0.72, 1.32, 2.64, and 6.60 mM ellagic acid with DNA (0.9 mM nucleotide) and [3H]MeNU (0.66 mM). HPLC analysis of DNA hydrolysates showed that ellagic acid caused a dose-dependent 36-84% decrease in O6-methylguanine but only a 20% decrease in the 7-methylguanine adduct. Under conditions where methylation at the O6 position of guanine in double-stranded DNA was inhibited 65% by ellagic acid, no significant inhibition of either O6- or 7-methylguanine formation was detected in single-stranded DNA. Affinity-binding studies revealed that [3H]ellagic acid binds equally to double-stranded or single-stranded DNA but that poly(dA X dT) binds 1.5 times as much ellagic acid as does poly(dG X dC). The binding of ellagic acid to DNA is dependent on the concentration of both ellagic acid and DNA. The specific inhibition of O6-methylguanine formation only in double-stranded DNA and the relatively low inhibition of 7-methylguanine formation rule out the possibility that ellagic acid prevents DNA alkylation by scavenging the electrophilic intermediate generated in the hydrolysis of MeNU. The results suggest that ellagic acid inhibition of MeNU-induced mutagenicity is due to specific inhibition of methylation at the O6 position of guanine through an ellagic acid-duplex DNA affinity-binding mechanism. PMID:3464940

  10. Hydrolysis of tert-butyl formate: Kinetics, products, and implications for the environmental impact of methyl tert-butyl ether

    USGS Publications Warehouse

    Church, Clinton D.; Pankow, James F.; Tratnyek, Paul G.

    1999-01-01

    Asessing the environmental fate of methyl tert-butyl ether (MTBE) has become a subject of renewed interest because of the large quantities of this compound that are being used as an oxygenated additive in gasoline. Various studies on the fate of MTBE have shown that it can be degraded to tert-butyl formate (TBF), particularly in the atmosphere. Although it is generally recognized that TBF is subject to hydrolysis, the kinetics and products of this reaction under environmentally relevant conditions have not been described previously. In this study, we determined the kinetics of TBF hydrolysis as a function of pH and temperature. Over the pH range of 5 to 7, the neutral hydrolysis pathway predominates, with kN = (1.0 ± 0.2) × 10−6/s. Outside this range, strong pH effects were observed because of acidic and basic hydrolyses, from which we determined that kA = (2.7 ± 0.5) × 10−3/(M·s) and kB = 1.7 ± 0.3/(M·s). Buffered and unbuffered systems gave the same hydrolysis rates for a given pH, indicating that buffer catalysis was not significant under the conditions tested. The activation energies corresponding to kN, kA, and kBwere determined to be 78 ± 5, 59 ± 4, and 88 ±11 kJ/mol, respectively. In all experiments, tert-butyl alcohol was found at concentrations corresponding to stoichiometric formation from TBF. Based on our kinetics data, the expected half-life for hydrolysis of TBF at pH = 2 and 4°C (as per some standard preservation protocols for water sampling) is 6 h. At neutral pH and 22°C, the estimated half-life is 5 d, and at pH = 11 and 22°C, the value is only 8 min.

  11. Chemical evolution. XXI - The amino acids released on hydrolysis of HCN oligomers

    NASA Technical Reports Server (NTRS)

    Ferris, J. P.; Wos, J. D.; Nooner, D. W.; Oro, J.

    1974-01-01

    Major amino acids released by hydrolysis of acidic and basic HCN oligomers are identified by chromatography as Gly, Asp, and diaminosuccinic acid. Smaller amounts of Ala, Ile and alpha-aminoisobutyric acid are also detected. The amino acids released did not change appreciably when the hydrolysis medium was changed from neutral to acidic or basic. The presence of both meso and d, l-diaminosuccinic acids was established by paper chromatography and on an amino acid analyzer.

  12. Zip nucleic acids are potent hydrolysis probes for quantitative PCR

    PubMed Central

    Paris, Clément; Moreau, Valérie; Deglane, Gaëlle; Voirin, Emilie; Erbacher, Patrick; Lenne-Samuel, Nathalie

    2010-01-01

    Zip nucleic acids (ZNAs) are oligonucleotides conjugated with cationic spermine units that increase affinity for their target. ZNAs were recently shown to enable specific and sensitive reactions when used as primers for polymerase chain reaction (PCR) and reverse-transcription. Here, we report their use as quantitative PCR hydrolysis probes. Ultraviolet duplex melting data demonstrate that attachment of cationic residues to the 3′ end of an oligonucleotide does not alter its ability to discriminate nucleotides nor the destabilization pattern relative to mismatch location in the oligonucleotide sequence. The stability increase provided by the cationic charges allows the use of short dual-labeled probes that significantly improve single-nucleotide polymorphism genotyping. Longer ZNA probes were shown to display reduced background fluorescence, therefore, generating greater sensitivity and signal level as compared to standard probes. ZNA probes thus provide broad flexibility in assay design and also represent an effective alternative to minor groove binder- and locked nucleic-acid-containing probes. PMID:20071749

  13. Robustness of two-step acid hydrolysis procedure for composition analysis of poplar.

    PubMed

    Bhagia, Samarthya; Nunez, Angelica; Wyman, Charles E; Kumar, Rajeev

    2016-09-01

    The NREL standard procedure for lignocellulosic biomass composition has two steps: primary hydrolysis in 72% wt sulfuric acid at 30°C for 1h followed by secondary hydrolysis of the slurry in 4wt% acid at 121°C for 1h. Although pointed out in the NREL procedure, the impact of particle size on composition has never been shown. In addition, the effects of primary hydrolysis time and separation of solids prior to secondary hydrolysis on composition have never been shown. Using poplar, it was found that particle sizes less than 0.250mm significantly lowered the glucan content and increased the Klason lignin but did not affect xylan, acetate, or acid soluble lignin contents. Composition was unaffected for primary hydrolysis time between 30 and 90min. Moreover, separating solids prior to secondary hydrolysis had negligible effect on composition suggesting that lignin and polysaccharides are completely separated in the primary hydrolysis stage.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Effect of acid hydrolysis on starch structure and functionality: a review.

    PubMed

    Wang, Shujun; Copeland, Les

    2015-01-01

    Acid hydrolysis is an important chemical modification that can significantly change the structural and functional properties of starch without disrupting its granular morphology. A deep understanding of the effect of acid hydrolysis on starch structure and functionality is of great importance for starch scientific research and its industrial applications. During acid hydrolysis, amorphous regions are hydrolyzed preferentially, which enhances the crystallinity and double helical content of acid hydrolyzed starch. This review discusses current understanding of the effect of acid hydrolysis on starch structure and functionality. The effects of acid hydrolysis on amylose content, chain length distribution of amylopectin molecules, molecular and crystalline organization (including lamellar structure) and granular morphology are considered. Functional properties discussed include swelling power, gelatinization, retrogradation, pasting, gel texture, and in vitro enzyme digestibility. The paper also highlights some promising applications of acid hydrolyzed starch (starch nanocrystals) in the preparation of biodegradable nanocomposites, bio-hydrogen, and slowly digestible starch-based healthy foods.

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

    PubMed

    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.

  17. 2-Methyl-4-chlorophenoxyacetic acid (MCPA)

    Integrated Risk Information System (IRIS)

    2 - Methyl - 4 - chlorophenoxyacetic acid ( MCPA ) ; CASRN 94 - 74 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard

  18. Hydrolysis study of organic acid anhydrides by differential thermal analysis-I Pyromellitic dianhydride.

    PubMed

    Rosenfeld, J M; Loncrini, D F; Murphy, C B

    1966-08-01

    A technique for following the hydrolysis of pyromellitic acid dianhydride (PMDA) by differential thermal analysis (DTA) is described. On exposure of PMDA to moisture, an endothennic peak is initiated between 190 and 200 degrees . As the degree of hydrolysis increases, this peak becomes more intense and shifts to higher temperatures. The formation of pyromellitic acid (PMA) during the hydrolysis of PMDA can be determined qualitatively by DTA.

  19. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  20. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  1. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  2. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  3. 40 CFR 721.8660 - Propionic acid methyl ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Propionic acid methyl ester (generic... Substances § 721.8660 Propionic acid methyl ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a propionic acid methyl...

  4. Neural Tube Defects, Folic Acid and Methylation

    PubMed Central

    Imbard, Apolline; Benoist, Jean-François; Blom, Henk J.

    2013-01-01

    Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects. PMID:24048206

  5. Neural tube defects, folic acid and methylation.

    PubMed

    Imbard, Apolline; Benoist, Jean-François; Blom, Henk J

    2013-09-17

    Neural tube defects (NTDs) are common complex congenital malformations resulting from failure of the neural tube closure during embryogenesis. It is established that folic acid supplementation decreases the prevalence of NTDs, which has led to national public health policies regarding folic acid. To date, animal studies have not provided sufficient information to establish the metabolic and/or genomic mechanism(s) underlying human folic acid responsiveness in NTDs. However, several lines of evidence suggest that not only folates but also choline, B12 and methylation metabolisms are involved in NTDs. Decreased B12 vitamin and increased total choline or homocysteine in maternal blood have been shown to be associated with increased NTDs risk. Several polymorphisms of genes involved in these pathways have also been implicated in risk of development of NTDs. This raises the question whether supplementation with B12 vitamin, betaine or other methylation donors in addition to folic acid periconceptional supplementation will further reduce NTD risk. The objective of this article is to review the role of methylation metabolism in the onset of neural tube defects.

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

    PubMed

    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.

  7. Value of furfural/ethanol coproduction from acid hydrolysis processes

    SciTech Connect

    Parker, S.; Calnon, M.; Feinberg, D.; Power, A.; Weiss, L.

    1983-08-01

    The benefits of two modifications in the acid hydrolysis of cellulosic feedstocks for the production of ethanol fuels were investigated: marketing of the by-product furfural and xylose fermentation. Preliminary analysis indicate that the furfural by-product furfural and xylose fermentation. Perliminary analyses indicate that the furfural by-product credit is more beneficial at a minimum net profit of $0.08/lb of furfural. For this credit to have a major impact on ethanol production costs, new markets for large quantities of furfural must be identified. Furfural can be an alternative feedstock for hydrocarbon-based commodity chemicals. The costs and profitabilities of producing five chemicals from furfurals as opposed to conventional hydrocarbon-based feedstocks were studied. The furfural processes for production of styrene and butadiene were found to be marginally competitive or not competitive. The furfural processes for adipic acid, maleic anhydride, and butanol could be competitive. Results of analysis by a computer model of the petrochemical industry indicate that with furfural markets additional to these three furfural processes, over 2.5 x 10/sup 9/ gal of ethanol could be marketed at about $1.00/gal. Converting the xylose stream to ethanol has about the same effect on the selling price of ethanol as the furfural credit. The greatest ethanol production will result from xylose fermentation, but the furfural credit offers large near-term profits and has a more diversified impact on reducing petroleum product demand. 6 figures, 17 tables.

  8. Hydrolase BioH knockout in E. coli enables efficient fatty acid methyl ester bioprocessing.

    PubMed

    Kadisch, Marvin; Schmid, Andreas; Bühler, Bruno

    2017-03-01

    Fatty acid methyl esters (FAMEs) originating from plant oils are most interesting renewable feedstocks for biofuels and bio-based materials. FAMEs can also be produced and/or functionalized by engineered microbes to give access to, e.g., polymer building blocks. Yet, they are often subject to hydrolysis yielding free fatty acids, which typically are degraded by microbes. We identified BioH as the key enzyme responsible for the hydrolysis of medium-chain length FAME derivatives in different E. coli K-12 strains. E. coli ΔbioH strains showed up to 22-fold reduced FAME hydrolysis rates in comparison with respective wild-type strains. Knockout strains showed, beside the expected biotin auxotrophy, unchanged growth behavior and biocatalytic activity. Thus, high specific rates (~80 U g CDW(-1) ) for terminal FAME oxyfunctionalization catalyzed by a recombinant alkane monooxygenase could be combined with reduced hydrolysis. Biotransformations in process-relevant two-liquid phase systems profited from reduced fatty acid accumulation and/or reduced substrate loss via free fatty acid metabolization. The BioH knockout strategy was beneficial in all tested strains, although its effect was found to differ according to specific strain properties, such as FAME hydrolysis and FFA degradation activities. BioH or functional analogs can be found in virtually all microorganisms, making bioH deletion a broadly applicable strategy for efficient microbial bioprocessing involving FAMEs.

  9. Fully automated system for the gas chromatographic characterization of polar biopolymers based on thermally assisted hydrolysis and methylation.

    PubMed

    Kaal, Erwin; de Koning, Sjaak; Brudin, Stella; Janssen, Hans-Gerd

    2008-08-08

    Pyrolysis-gas chromatography (Py-GC) is a powerful tool for the detailed compositional analysis of polymers. A major problem of Py-GC is that polar (bio)polymers yield polar pyrolyzates which are not easily accessible to further GC characterization. In the present work, a newly developed fully automated procedure for thermally assisted hydrolysis and methylation (THM) of biopolymers is described. Drying of the sample, addition of the reagent, incubation and pyrolysis are performed inside the liner of a programmable temperature vaporizer injector. The new system not only allows efficient analysis of large series of samples, but also allows automated optimization of the experimental parameters based on an experimental design approach. The performance of the automated THM-procedure was evaluated by performing THM-GC of a poly(acrylic acid)-poly(maleic anhydride) copolymer (PAA/PMAH) and several polysaccharides. The optimized THM-procedure was applied for the structural characterization and differentiation of several lignins and hydroxypropylmethyl-celluloses. It was also applied to proteins. Here myoglobin and cytochrome c were used as the model compounds. Both conventional GC-mass spectrometry (MS) and comprehensive two-dimensional gas chromatography (GCxGC)-time-of-flight (TOF) MS were used for separation and identification of the species formed. The information obtained can aid in structure elucidation of polar biopolymers as well as in providing detailed compositional information which can be used to differentiate structurally similar biopolymers.

  10. Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

    PubMed

    Huang, Yanqin; Wei, Zhiguo; Yin, Xiuli; Wu, Chuangzhi

    2012-01-01

    Pyrolytic characteristics of acid hydrolysis residue (AHR) of corncob and pinewood (CAHR, WAHR) were investigated using a thermo-gravimetric analyzer (TGA) and a self-designed pyrolysis apparatus. Gasification reactivity of CAHR char was then examined using TGA and X-ray diffractometer. Result of TGA showed that thermal degradation curves of AHR descended smoothly along with temperature increasing from 150 °C to 850 °C, while a "sharp mass loss stage" for original biomass feedstock (OBF) was observed. Char yield from AHR (42.64-30.35 wt.%) was found to be much greater than that from OBF (26.4-19.15 wt.%). In addition, gasification reactivity of CAHR char was lower than that of corncob char, and there was big difference in micro-crystallite structure. It was also found that CAHR char reactivity decreased with pyrolysis temperature, but increased with pyrolysis heating rate and gasification temperature at 850-950 °C. Furthermore, CAHR char reactivity performed better under steam atmosphere than under CO2 atmosphere.

  11. Photochromic Properties of a Water Soluble Methyl Carboxylic Acid Indolylfulgimide

    PubMed Central

    Chen, Xi; Islamova, Nadezhda I.; Robles, Rachel V.

    2011-01-01

    Photochromic fulgides and fulgimides have been identified as promising materials for applications in optical memory media, optical switches, and sensors. For applications in humid environments or biological systems, hydrolytic stability is crucial. A new photochromic methyl carboxylic acid indolylfulgimide was synthesized to improve hydrolytic stability in aqueous solution. The UV-vis spectra, extinction coefficient, thermal stability, and photochemical stability of the fulgimide were characterized in 50 mM sodium phosphate buffer (pH 7.4). The open and closed forms were both stable in buffer. At 37 °C after 500 h, the open forms of the fulgimide showed no degradation within experimental error (1–2%) by 1H NMR and 2.3% decomposition by UV-vis spectroscopy. The closed form degraded 22% and 11% after 500 h at 37 °C in buffer by UV-vis and 1H NMR data, respectively. In addition, the fulgimide cycled back and forth between the open and closed forms 80 times before degrading by 20% in buffer. The methyl group at the bridging position of the fulgimide significantly increased the thermal stability by overcoming the rapid hydrolysis of the trifluoromethyl group. PMID:21380459

  12. Differential effects of Mg(ii) and N(alpha)-4-tosyl-l-arginine methyl ester hydrochloride on the recognition and catalysis in ATP hydrolysis.

    PubMed

    Ma, Yanqing; Lu, Gongxuan

    2008-02-28

    The supramolecular interactions of Mg(ii) and N(alpha)-4-tosyl-l-arginine methyl ester hydrochloride (TAME) with ATP have been investigated using (1)H and (31)P NMR spectra. Furthermore, the hydrolysis of ATP catalyzed by Mg(ii) and TAME has been studied at 60 degrees C and pH 7 using (31)P NMR spectra. In the Mg(ii)-ATP-TAME ternary system, the binding interaction of Mg(2+) with ATP involves not only N1 and N7 in the adenine ring but also beta- and gamma-phosphate of ATP. The binding forces are mainly electrostatic interaction and cation (Mg(2+))-pi interaction. The guanidinium group and the aromatic ring of TAME interacts with ATP by beta and gamma phosphate and the adenine ring of ATP. The binding forces are mainly electrostatic interactions and pi-pi stacking. A significant difference between the binary and the ternary system indicates that TAME is essential to the stablization of the intermediate. Kinetic studies show that the hydrolysis rate constant of ATP is 2.16 x 10(-2) h(-1) at pH 7 in the Mg(ii)-TAME-ATP ternary system. The Mg(ii) ion and TAME can accelerate the ATP hydrolysis process. A possible mechanism has been proposed that the hydrolysis occurs through an addition-elimination, in which the phosphoramidate intermediate was observed at 3.21 ppm in the (31)P NMR of the ternary system. These results provide further information concerning the effect of the key amino acid residue and metal ions as cofactors of ATPase on ATP synthesis/hydrolysis at the molecular level.

  13. Comparison of enzymatic and acid hydrolysis of bound flavor compounds in model system and grapes.

    PubMed

    Dziadas, Mariusz; Jeleń, Henryk H

    2016-01-01

    Four synthesized terpenyl-ß-D-glycopyranosides (geranyl, neryl, citronellyl, myrtenyl) were subjected to enzymatic (AR 2000, pH 5.5) and acid (citric buffer, pH 2.5) hydrolysis. Decrease of glycosides was measured by HPLC and the volatiles released--by comprehensive gas chromatography-mass spectrometry (GC × GC-ToF-MS). Enzymatic hydrolysis performed for 21 h yielded 100% degree of hydrolysis for all glycosides but citronellyl (97%). Degree of acid hydrolysis was highly dependent on type of aglycone and the conditions. The highest degree was achieved for geraniol, followed by citronellol and nerol. Myrtenylo-ß-D-glycopyranoside was the most resistant glycoside to hydrolysis. Acid hydrolysis degree was also related to temperature/time combination, the highest being for 100 °C and 2 h. In a result of enzymatic hydrolysis 85-91% of total peak areas was terpene aglycone, whereas for acid hydrolysis the area of released terpene aglycone did not exceed 1.3% of total peak area indicating almost complete decomposition/transformation of terpenyl aglycone.

  14. Accelerating the initial rate of hydrolysis of methyl parathion with laser excitation using monolayer protected 10 nm Au nanoparticles capped with a Cu(bpy) catalyst.

    PubMed

    Trammell, Scott A; Nita, Rafaela; Moore, Martin; Zabetakis, Dan; Chang, Eddie; Knight, D Andrew

    2012-04-28

    Using a low power green laser, we have demonstrated a rate acceleration of ~2-fold for the hydrolysis of methyl parathion by irradiating the plasmon absorption band of Au nanoparticles capped with a Cu(bpy) catalyst.

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

    SciTech Connect

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

    2014-04-28

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

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Impact of α-amylase combined with hydrochloric acid hydrolysis on structure and digestion of waxy rice starch.

    PubMed

    Li, Hongyan; Zhu, Yanqiao; Jiao, Aiquan; Zhao, Jianwei; Chen, Xiaoming; Wei, Benxi; Hu, Xiuting; Wu, Chunsen; Jin, Zhengyu; Tian, Yaoqi

    2013-04-01

    The structure and in vitro digestibility of native waxy rice starch by the combined hydrolysis of α-amylase and hydrochloric acid were investigated in this study. The combined hydrolysis technique generated higher hydrolysis rate and extent than the enzymatic hydrolysis. The granular appearance and chromatograph profile demonstrated that α-amylase and hydrochloric acid exhibited different patterns of hydrolysis. The rise in the ratio of absorbance 1047/1022cm(-1), the melting temperature range (Tc-To), and the melting enthalpy (ΔH) were observed during the combined hydrolysis. These results suggest that α-amylase simultaneously cleaves the amorphous and crystalline regions, whereas the amorphous regions of starch granules are preferentially hydrolyzed during the acid hydrolysis. Furthermore, the combined hydrolysis increased rapidly digestible starch (RDS) while decreased slowly digestible starch (SDS) and resistant starch (RS), indicating that the hydrolysis mode affected the digestion property of native waxy rice starch.

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

    PubMed Central

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

    2013-01-01

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

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

    PubMed

    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 < 0.05. High F and R (2) values and low P-value for hydrolysis yield indicated the model predictability. The pretreated biomass producing 39.96 g/l, 39.86 g/l and 37.9 g/l of reducing sugars during enzymatic hydrolysis with yield 79.93, 78.71 and 75.9 % from PA, MA and SA treated respectively. The order of catalytic effectiveness for hydrolysis yield was found to be phosphoric acid > maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker's yeast (Sacchromyces cerveasiae).

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

    PubMed

    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.

  1. Hydrolysis of tRNA(sup Phe) on Suspensions of Amino Acids

    NASA Technical Reports Server (NTRS)

    Gao, Kui; Orgel, Leslie E.

    2001-01-01

    RNA is adsorbed strongly on suspensions of many moderately soluble organic solids. In some cases, the hydrolysis of tRNA(sup Phe) is greatly accelerated by adsorption, and the major sites of hydrolysis are changed from those that are important in homogeneous solution. Here we show that the hydrolysis is greatly accelerated by suspensions of aspartic acid and beta-glutamic acid but not by suspensions of alpha-glutamic acid, asparagine, or glutamine. The non-enzymatic hydrolysis of RNA has been studied extensively, especially because of its relevance to the mechanisms of action of ribozymes and to biotechnology and therapy. Many ribonucleases, ribozymes, and non-biological catalysts function via acid-base catalysis of an intramolecular transesterification mechanism in which the 2'-OH group attacks the adjacent phosphate group. The pentacoordinated phosphorane intermediate may collapse back to starting material, or yield isomerized or cleaved products.

  2. Production of methyl-vinyl ketone from levulinic acid

    DOEpatents

    Dumesic, James A.; West; Ryan M.

    2011-06-14

    A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.

  3. Increased diazinon hydrolysis to 2-isopropyl-6-methyl-4-pyrimidinol in liquid medium by a specific Streptomyces mixed culture.

    PubMed

    Briceño, G; Schalchli, H; Rubilar, O; Tortella, G R; Mutis, A; Benimeli, C S; Palma, G; Diez, M C

    2016-08-01

    Actinobacteria identified as Streptomyces spp. were evaluated for their ability to remove diazinon as the only carbon source from a liquid medium. Single cultures of Streptomyces strains were exposed to diazinon at a concentration of 50 mg L(-1). After 96 h incubation, six of the eight cultures grew and five strains showed an increase in their total protein concentrations and changes in their protein profile. Up to 32% of the diazinon was removed by the single Streptomyces cultures. A compatibility assay showed that the different Streptomyces species were not antagonistic. Twenty-six mixed cultures were then prepared. Diazinon removal was increased when mixed cultures were used, and maximum diazinon removal of 62% was observed when the Streptomyces spp. strains AC5, AC9, GA11 and ISP13 were mixed; this was defined as the selected mixed culture (SMC). Diazinon removal was positively influenced by the addition of glucose into the liquid medium. Our study showed a diazinon degradation rate of 0.025 h(-1), half-life of 28 h(-1) and 2-isopropyl-6-methyl-4-pyrimidinol (IMHP) production of 0.143 mg L h(-1). Rapid diazinon hydrolysis to IMHP was associated with a decrease in the pH of the medium as a consequence of microbial glucose metabolism and organic acid exudation. Moreover, the SMC of Streptomyces was able to remove IMHP. This work constitutes a new, if not the only, report on diazinon degradation by mixed cultures of Streptomyces spp. Given the high levels of diazinon removal, the SMC formed by four Streptomyces strains has the potential to be used to treat the diazinon present in environmental matrices.

  4. Chemical structures of corn stover and its residue after dilute acid prehydrolysis and enzymatic hydrolysis: Insight into factors limiting enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advanced solid-state NMR techniques and wet chemical analyses were applied to investigate untreated corn stover (UCS) and its residues after dilute acid prehydrolysis (DAP) and enzymatic hydrolysis (RES) to provide evidence for the limitations to the effectiveness of enzyme hydrolysis. Advanced soli...

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

    PubMed

    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.

  6. Pyrrolidone - a new solvent for the methylation of humic acid

    USGS Publications Warehouse

    Wershaw, R. L.; Pinckney, D.J.; Booker, S.E.

    1975-01-01

    In the past, humic acid has been methylated by suspending it in a solution of diazomethane in diethyl ether, and degrading the partly methylated humic acid to release those parts of the molecule that were methylated. Only small fragments of the molecule have been identified by this technique. In the procedure described here the humic acid is dissolved in 2-pyrrolidone and methylated by the addition of diazomethane in diethyl ether and ethanol to the solution. Because the humic acid is completely dissolved in the reaction medium, disaggregation of the humic acid particles takes place and much more complete methylation is obtained. The methylated products may be fractionated by countercurrent distribution and analyzed by mass spectrometry.

  7. Studying Cellulose Fiber Structure by SEM, XRD, NMR and Acid Hydrolysis

    SciTech Connect

    Zhao, Haibo; Kwak, Ja Hun; Zhang, Z. Conrad; Brown, Heather M.; Arey, Bruce W.; Holladay, John E.

    2007-03-21

    Cotton linters were partially hydrolyzed in dilute acid and the morphology of remaining macrofibrils studied with Scanning Electron Microscopy (SEM) under various magnifications. The crystal region (microfibril bundles) in the macrofibrils was not altered by hydrolysis, and only amorphous cellulose was hydrolyzed and leached out from the macrofibrils. The diameter of microfibril bundles was 20-30 nm after the amorphous cellulose was removed by hydrolysis. XRD experiments confirm the unaltered diameter of the microfibrils after hydrolysis. The strong stability of these microfibril bundles in hydrolysis limits both the total sugar monomer yield and the size of nano particles or rods produced in hydrolysis. The large surface potential on the remaining microfibril bundles drives the agglomeration of macrofibrils.

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

    PubMed

    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.

  9. Efficient hydrogen generation from sodium borohydride hydrolysis using silica sulfuric acid catalyst

    NASA Astrophysics Data System (ADS)

    Manna, Joydev; Roy, Binayak; Sharma, Pratibha

    2015-02-01

    A heterogeneous acid catalyst, silica sulfuric acid, was prepared from silica gel (SiO2) and sulfuric acid (H2SO4). Addition of SO3H functional group to SiO2 has been confirmed through various characterization techniques. The effect of this heterogeneous acid catalyst on hydrogen generation from sodium borohydride hydrolysis reaction was studied for different ratios of catalyst to NaBH4 and at different temperatures. The catalyst exhibited high catalytic activity towards sodium borohydride hydrolysis reaction. The activation energy of the NaBH4 hydrolysis reaction in the presence of silica sulfuric acid was calculated to be the lowest (17 kJ mol-1) among reported heterogeneous catalysts till date.

  10. Obtaining fermentable sugars by dilute acid hydrolysis of hemicellulose and fast pyrolysis of cellulose.

    PubMed

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

    2015-04-01

    The objective of this study was to get fermentable sugars by dilute acid hydrolysis of hemicellulose and fast pyrolysis of cellulose from sugarcane bagasse. Hemicellulose could be easily hydrolyzed by dilute acid as sugars. The remained solid residue of acid hydrolysis was utilized to get levoglucosan by fast pyrolysis economically. Levoglucosan yield from crystalline cellulose could be as high as 61.47%. Dilute acid hydrolysis was also a promising pretreatment for levoglucosan production from lignocellulose. The dilute acid pretreated sugarcane bagasse resulted in higher levoglucosan yield (40.50%) in fast pyrolysis by micropyrolyzer, which was more effective than water washed (29.10%) and un-pretreated (12.84%). It was mainly ascribed to the effective removal of alkali and alkaline earth metals and the accumulation of crystalline cellulose. This strategy seems a promising route to achieve inexpensive fermentable sugars from lignocellulose for biorefinery.

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

    SciTech Connect

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

    1982-07-01

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

  12. Hydrolysis of Sulfur Dioxide in Small Clusters of Sulfuric Acid: Mechanistic and Kinetic Study.

    PubMed

    Liu, Jingjing; Fang, Sheng; Wang, Zhixiu; Yi, Wencai; Tao, Fu-Ming; Liu, Jing-Yao

    2015-11-17

    The deposition and hydrolysis reaction of SO2 + H2O in small clusters of sulfuric acid and water are studied by theoretical calculations of the molecular clusters SO2-(H2SO4)n-(H2O)m (m = 1,2; n = 1,2). Sulfuric acid exhibits a dramatic catalytic effect on the hydrolysis reaction of SO2 as it lowers the energy barrier by over 20 kcal/mol. The reaction with monohydrated sulfuric acid (SO2 + H2O + H2SO4 - H2O) has the lowest energy barrier of 3.83 kcal/mol, in which the cluster H2SO4-(H2O)2 forms initially at the entrance channel. The energy barriers for the three hydrolysis reactions are in the order SO2 + (H2SO4)-H2O > SO2 + (H2SO4)2-H2O > SO2 + H2SO4-H2O. Furthermore, sulfurous acid is more strongly bonded to the hydrated sulfuric acid (or dimer) clusters than the corresponding reactant (monohydrated SO2). Consequently, sulfuric acid promotes the hydrolysis of SO2 both kinetically and thermodynamically. Kinetics simulations have been performed to study the importance of these reactions in the reduction of atmospheric SO2. The results will give a new insight on how the pre-existing aerosols catalyze the hydrolysis of SO2, leading to the formation and growth of new particles.

  13. Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

    PubMed

    Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

    2012-01-01

    In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

  14. Effect of defatting on acid hydrolysis rate of maize starch with different amylose contents.

    PubMed

    Wei, Benxi; Hu, Xiuting; Zhang, Bao; Li, Hongyan; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2013-11-01

    The effect of defatting on the physiochemical properties and the acid hydrolysis rate of maize starch with different amylose contents was evaluated in this study. The increase in the number of pores and the stripping of starch surface layers were observed after defatting by scanning electron microscopy. X-ray diffraction spectrum showed that the peaks attributing to the amylose-lipid complex disappeared. The relative crystallinity increased by 19% for high-amylose maize starch (HMS) on defatting, while the other tested starches virtually unchanged. Differential scanning calorimetry study indicated an increase in the thermal stability for the defatted starches. Compared with native waxy maize starch, the acid hydrolysis rate of the defatted one increased by 6% after 10 days. For normal maize starch (NMS) and HMS, the higher rate of hydrolysis was observed during the first 5 days. Thereafter, the hydrolysis rate was lower than that of their native counterpart. The increase in susceptibility to acid hydrolysis (in the first 5 days) was mainly attributed to the defective and porous structures formed during defatting process, while the decrease of hydrolysis rate for NMS and HMS samples (after the first 5 days) probably resulted from the increase in the relative crystallinity.

  15. High-yield production of biosugars from Gracilaria verrucosa by acid and enzymatic hydrolysis processes.

    PubMed

    Kim, Se Won; Hong, Chae-Hwan; Jeon, Sung-Wan; Shin, Hyun-Jae

    2015-11-01

    Gracilaria verrucosa, the red alga, is a suitable feedstock for biosugar production. This study analyzes biosugar production by the hydrolysis of G. verrucosa conducted under various conditions (i.e., various acid concentrations, substrate concentrations, reaction times, and enzyme dosages). The acid hydrolysates of G. verrucosa yielded a total of 7.47g/L (37.4%) and 10.63g/L (21.26%) of reducing sugars under optimal small (30mL) and large laboratory-scale (1L) hydrolysis processes, respectively. Reducing sugar obtained from acid and enzymatic hydrolysates were 10% higher, with minimum by-products, than those reported in other studies. The mass balance for the small laboratory-scale process showed that the acid and enzymatic hydrolysates had a carbohydrate conversion of 57.2%. The mass balance approach to the entire hydrolysis process of red seaweed for biosugar production can be applied to other saccharification processes.

  16. Chain-length-dependent autocatalytic hydrolysis of fatty acid anhydrides in polyethylene glycol.

    PubMed

    Cao, Cao; Wang, Qing-Biao; Tang, Lin-Jun; Ge, Bing-Qiang; Chen, Zhong-Xiu; Deng, Shao-Ping

    2014-03-27

    Autocatalytic hydrolysis of fatty acid anhydrides induced by the spontaneously formed vesicles has been studied for years. However, whether the reaction autocatalyzed by vesicles formed in diluted solutions applies also to macromolecular crowded conditions remains unknown. The aim of this study is to characterize hydrolysis behavior of fatty acid anhydrides and formation of vesicles in crowded media. Inert macromolecular crowding agents such as polyethylene glycol (PEG) and Dextran were used to probe the impact of external crowding on the autocatalytic hydrolysis of fatty acid anhydrides with varied hydrophobic chain length. Under stringent conditions of crowding, hydrolysis rates of octanoic anhydride, nonanoic anhydride, and decanoic anhydride were found to decrease, but the rates of lauric anhydride and oleic anhydride increased. These results suggest that the effect of the crowding agent on the hydrolysis of fatty acid anhydrides was chain-length-dependent. Characterization of the size and polydispersity of vesicles formed from hydrolyzed fatty acid anhydrides in crowding revealed that long-chain fatty acids formed monodisperse vesicles easier at lower concentrations of PEG. Measurement of the critical aggregation concentration of ionized fatty acid in the presence of PEG showed that crowding media promoted vesicle formation from long-chain fatty acids but inhibited those from fatty acids with fewer carbon atoms. Further investigation of the diffusion property of ionized fatty acids in crowding agents suggested that PEG might create more hydrophobic areas for long-chain fatty acids anhydrides, which subsequently promoted the unreacted anhydride in the aqueous phase to be solubilized in the formed vesicles. This research provides information for understanding the autocatalytic reaction accompanied by self-producing aggregates and the behavior of fatty acids in crowding media.

  17. Preparation of κ-carra-oligosaccharides with microwave assisted acid hydrolysis method

    NASA Astrophysics Data System (ADS)

    Li, Guangsheng; Zhao, Xia; Lv, Youjing; Li, Miaomiao; Yu, Guangli

    2015-04-01

    A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL-1; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 °C min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Combined heat treatment and acid hydrolysis of cassava grate waste (CGW) biomass for ethanol production

    SciTech Connect

    Agu, R.C.; Amadife, A.E.; Ude, C.M.; Onyia, A.; Ogu, E.O.; Okafor, M.; Ezejiofor, E.

    1997-12-31

    The effect of combined heat treatment and acid hydrolysis (various concentrations) on cassava grate waste (CGW) biomass for ethanol production was investigated. At high concentrations of H{sub 2}SO{sub 4} (1--5 M), hydrolysis of the CGW biomass was achieved but with excessive charring or dehydration reaction. At lower acid concentrations, hydrolysis of CGW biomass was also achieved with 0.3--0.5 M H{sub 2}SO{sub 4}, while partial hydrolysis was obtained below 0.3 M H{sub 2}SO{sub 4} (the lowest acid concentration that hydrolyzed CGW biomass) at 120 C and 1 atm pressure for 30 min. A 60% process efficiency was achieved with 0.3 M H{sub 2}SO{sub 4} in hydrolyzing the cellulose and lignin materials present in the CGW biomass. High acid concentration is therefore not required for CGW biomass hydrolysis. The low acid concentration required for CGW biomass hydrolysis, as well as the minimal cost required for detoxification of CGW biomass because of low hydrogen cyanide content of CGW biomass would seem to make this process very economical. From three liters of the CGW biomass hydrolysate obtained from hydrolysis with 0.3M H{sub 2}SO{sub 4}, ethanol yield was 3.5 (v/v%) after yeast fermentation. However, although the process resulted in gainful utilization of CGW biomass, additional costs would be required to effectively dispose new by-products generated from CGW biomass processing.

  20. Ultrasonic pretreatment and acid hydrolysis of sugarcane bagasse for succinic acid production using Actinobacillus succinogenes.

    PubMed

    Xi, Yong-lan; Dai, Wen-yu; Xu, Rong; Zhang, Jiu-hua; Chen, Ke-quan; Jiang, Min; Wei, Ping; Ouyang, Ping-kai

    2013-11-01

    Immense interest has been devoted to the production of bulk chemicals from lignocellulose biomass. Diluted sulfuric acid treatment is currently one of the main pretreatment methods. However, the low total sugar concentration obtained via such pretreatment limits industrial fermentation systems that use lignocellulosic hydrolysate. Sugarcane bagasse hemicellulose hydrolysate is used as the carbon and nitrogen sources to achieve a green and economical production of succinic acid in this study. Sugarcane bagasse was ultrasonically pretreated for 40 min, with 43.9 g/L total sugar obtained after dilute acid hydrolysis. The total sugar concentration increased by 29.5 %. In a 3-L fermentor, using 30 g/L non-detoxified total sugar as the carbon source, succinic acid production increased to 23.7 g/L with a succinic acid yield of 79.0 % and a productivity of 0.99 g/L/h, and 60 % yeast extract in the medium could be reduced. Compared with the detoxified sugar preparation method, succinic acid production and yield were improved by 20.9 and 20.2 %, respectively.

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

    PubMed

    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.

  2. Effect of limited enzymatic hydrolysis on linoleic acid binding properties of β-lactoglobulin.

    PubMed

    Sponton, Osvaldo E; Perez, Adrián A; Carrara, Carlos; Santiago, Liliana G

    2014-03-01

    β-Lactoglobulin (BLG) is a member of lipocalin family, proteins with ability to bind small hydrophobic ligands, such as retinol, vitamins and fatty acids. Moreover, BLG is susceptible to protease action producing a wide range of polypeptides depending on the hydrolysis degree (HD). In the present work, the effect of limited enzymatic hydrolysis on fatty acid binding properties of BLG was studied. Linoleic acid (LA) was used as a model fatty acid. Limited enzymatic hydrolysis was performed using α-chymotrypsin immobilised on agarose microparticles. BLG hydrolysates were produced at HD: 1%, 3% and 5%. In order to determine the influence of HD on BLG molecular weight SDS-PAGE was used. BLG structural modification and LA binding properties were monitored by means of fluorescence spectroscopic techniques. The increase in HD produced: (i) a BLG degradation and a molecular weight distribution of BLG hydrolysates and (ii) an increased exposition of buried hydrophobic residues, however it was observed a decrease in surface hydrophobicity possibly due to a deterioration of hydrophobic protein domains. It was observed that enzymatic hydrolysis treatment produced a decrease in BLG ability for binding LA. It was concluded that limited enzymatic hydrolysis could deteriorate the specific site on BLG structure necessary for binding LA.

  3. Amino acid composition determined using multiple hydrolysis times for three goat milk formulations.

    PubMed

    Rutherfurd, Shane M; Moughan, Paul J; Lowry, Dianne; Prosser, Colin G

    2008-01-01

    The amino acid composition of goat milk formulations with varying protein and carbohydrate concentrations were determined. Proteins in goat milk infant formula, goat milk growing-up formula and goat whole milk powder were hydrolysed using multiple hydrolysis time intervals. A least-squares non-linear regression model was used to predict the free and protein bound amino acid concentrations. The amino acid composition of goat infant formula was compared with human milk reference values. There was good agreement between the multiple hydrolysis and single 24-h hydrolysis methods for approximately one-half of the amino acids. Tryptophan, aspartic acid, threonine, tyrosine, isoleucine, valine, serine and alanine contents were underestimated by 10.6, 5.6, 5.6, 4.7, 4.4, 3.7, 3.7 and 3.6%, respectively, by the single 24-h hydrolysis. The study provides accurate reference data on the amino acid composition of goat milk powders. Goat milk infant formula has amino acids in amounts similar to human milk reference values, when expressed on a per-energy basis.

  4. Comparison of aqueous ammonia and dilute acid pretreatment of bamboo fractions: Structure properties and enzymatic hydrolysis.

    PubMed

    Xin, Donglin; Yang, Zhong; Liu, Feng; Xu, Xueru; Zhang, Junhua

    2015-01-01

    The effect of two pretreatments methods, aqueous ammonia (SAA) and dilute acid (DA), on the chemical compositions, cellulose crystallinity, morphologic change, and enzymatic hydrolysis of bamboo fractions (bamboo yellow, timber, green, and knot) was compared. Bamboo fractions with SAA pretreatment had better hydrolysability than those with DA pretreatment. High crystallinity index resulted in low hydrolysis yield in the conversion of SAA pretreated bamboo fractions, not DA pretreated fractions. The increase of cellulase loading had modestly positive effect in the hydrolysis of both SAA and DA pretreated bamboo fractions, while supplement of xylanase significantly increased the hydrolysis of the pretreated bamboo fractions, especially after SAA pretreatment. The results indicated that SAA pretreatment was more effective than DA pretreatment in conversion of bamboo fractions, and supplementation of xylanase was necessary in effective conversion of the SAA pretreated fractions into fermentable sugars.

  5. Acid hydrolysis of native corn starch: morphology, crystallinity, rheological and thermal properties.

    PubMed

    Utrilla-Coello, R G; Hernández-Jaimes, C; Carrillo-Navas, H; González, F; Rodríguez, E; Bello-Pérez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2014-03-15

    The acid hydrolysis of native corn starch at 35 °C was monitored during 15 days. After this time, the residual solids were about 37.0 ± 3.0%. First-order kinetics described the hydrolysis data, giving a constant rate of kH = 0.18 ± 0.012 days(-1). Amylose content presented a sharp decrement of about 85% and X-ray diffraction results indicated a gradual increase in crystallinity during the first 3 days. SEM micrographs showed that hydrolysis disrupted granule morphology from an initial regular shape to increasingly irregular shapes. Fractal analysis of SEM images revealed an increase in surface roughness. Fast changes in the thermal effects were caused by molecular rearrangements after fast hydrolysis of amylose in the amorphous regions in the first day. Steady shear rate and oscillatory tests showed a sharp decrease of the apparent viscosity and an increase of the damping factor (tan(δ)) caused by amylose degradation.

  6. Efficient production of glucose by microwave-assisted acid hydrolysis of cellulose hydrogel.

    PubMed

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

    2015-09-01

    To improve the production of glucose from cellulose, a simple and effective route was developed. This process uses a combination of a step of cellulose dissolution in aqueous NaOH/urea solution and then regeneration with water, followed by an acid hydrolysis step under microwave irradiation. The method is effective to obtain glucose from α-cellulose, microcrystalline cellulose, filter paper, ramie fiber and absorbent cotton. Increased with the acid concentration the glucose yield from hydrogel hydrolysis increased from 0.42% to 44.6% at 160 °C for 10 min. Moreover, the ozone treatment of cellulose in NaOH/urea solution before regeneration significantly enhanced the hydrolysis efficiency with a glucose yield of 59.1%. It is believed that the chains in cellulose hydrogel are relatively free approached, making that the acids easily access the β-glycosidic bonds.

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

    SciTech Connect

    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.

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

    SciTech Connect

    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.

  9. Protective effect of phytic acid hydrolysis products on iron-induced lipid peroxidation of liposomal membranes.

    PubMed

    Miyamoto, S; Kuwata, G; Imai, M; Nagao, A; Terao, J

    2000-12-01

    Beneficial effects of dietary phytic acid (myo-inositol hexaphosphate; IP6) have often been explained by its strong iron ion-chelating ability, which possibly suppresses iron ion-induced oxidative damage in the gastrointestinal tract. Because phytic acid is hydrolyzed during digestion, this work aimed to know whether its hydrolysis products (IP2, IP3, IP4, and IP5) could still prevent iron ion-induced lipid peroxidation. Studies using liposomal membranes demonstrated that hydrolysis products containing three or more phosphate groups are able to inhibit iron ion-induced lipid peroxidation although their effectiveness decreased with dephosphorylation. Similarly, they also prevented iron ion-induced decomposition of phosphatidylcholine hydroperoxide. These results demonstrate that intermediate products of phytic acid hydrolysis still possess iron ion-chelating ability, and thus they can probably prevent iron ion-induced lipid peroxidation in biological systems.

  10. Quick characterization of uronic acid-containing polysaccharides in 5 shellfishes by oligosaccharide analysis upon acid hydrolysis.

    PubMed

    Liu, Bin; Lu, Jiaojiao; Ai, Chunqing; Zhang, Bao; Guo, Li; Song, Shuang; Zhu, Beiwei

    2016-11-29

    Uronic acid-containing polysaccharides (UACPs) including well-known glycosaminoglycans (GAGs) and some non-GAGs exist widely in animal kingdom. Although numerous methods have been established to analyze GAGs, few methods are available for non-GAG UACPs. In the present study, a protocol to identify all kinds of UACPs with repeating disaccharide units of hexosamine and uronic acid was demonstrated, and UACP components in five shellfishes, namely Turritella fortilirata Sowerby (GTF), Batillaria zonalis (GBZ), Nassarius variciferus (GNV), Monodonta labio Linnaeus (GML), and Argopecten irradians Lamarck (BAI) were primarily revealed. After a simple isolation procedure, crude polysaccharides were depolymerized by controlled acid hydrolysis, and then the resulting oligosaccharides were detected by HPLC coupled with mass spectrometer after 1-phenyl-3-methyl-5-pyrazolone (PMP) labeling. According to chromatograms using the triple quadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode, chondroitin sulfate (CS) was found in GNV and GML, a non-GAG named abalone gonad sulfated polysaccharide (AGSP) with a backbone of →4)-β-GlcA-(1 → 2)-α-Man-(1→ repeating units in GBZ, and both of AGSP and CS in BAI and GTF. Further characterization of tetrasaccharides and sulfated/acetylated disaccharides by HPLC combined with an ion trap mass spectrometer confirmed the structural identification of CS and AGSP, and indicated CS in GTF and BAI was Type C. These results suggest the 5 mollusks as potential resources for CS and AGSP. And the analysis protocol presented in this study was powerful and effective for quick characterization of UACPs including GAGs as well as non-GAGs in complicated matrix.

  11. Acid hydrolysis of Curcuma longa residue for ethanol and lactic acid fermentation.

    PubMed

    Nguyen, Cuong Mai; Nguyen, Thanh Ngoc; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Park, Youn-Je; Kim, Jin-Cheol

    2014-01-01

    This research examines the acid hydrolysis of Curcuma longa waste, to obtain the hydrolysate containing lactic acid and ethanol fermentative sugars. A central composite design for describing regression equations of variables was used. The selected optimum condition was 4.91% sulphuric acid, 122.68°C and 50 min using the desirability function under the following conditions: the maximum reducing sugar (RS) yield is within the limited range of the 5-hydroxymethylfurfural (HMF) and furfural concentrations. Under the condition, the obtained solution contained 144 g RS/L, 0.79 g furfural/L and 2.59 g HMF/L and was directly fermented without a detoxification step. The maximum product concentration, average productivity, RS conversion and product yield were 115.36 g/L, 2.88 g/L/h, 89.43% and 64% for L-lactic acid; 113.92 g/L, 2.59 g/L/h, 88.31% and 63.29% for D-lactic acid; and 55.03 g/L, 1.38 g/L/h, 42.66 and 30.57%, respectively, for ethanol using a 7-L jar fermenter.

  12. Heterogeneous ceria catalyst with water-tolerant Lewis acidic sites for one-pot synthesis of 1,3-diols via Prins condensation and hydrolysis reactions.

    PubMed

    Wang, Yehong; Wang, Feng; Song, Qi; Xin, Qin; Xu, Shutao; Xu, Jie

    2013-01-30

    The use of a heterogeneous Lewis acid catalyst, which is insoluble and easily separable during the reaction, is a promising option for hydrolysis reactions from both environmental and practical viewpoints. In this study, ceria showed excellent catalytic activity in the hydrolysis of 4-methyl-1,3-dioxane to 1,3-butanediol in 95% yield and in the one-pot synthesis of 1,3-butanediol from propylene and formaldehyde via Prins condensation and hydrolysis reactions in an overall yield of 60%. In-depth investigations revealed that ceria is a water-tolerant Lewis acid catalyst, which has seldom been reported previously. The ceria catalysts showed rather unusual high activity in hydrolysis, with a turnover number (TON) of 260, which is rather high for bulk oxide catalysts, whose TONs are usually less than 100. Our conclusion that ceria functions as a Lewis acid catalyst in hydrolysis reactions is firmly supported by thorough characterizations with IR and Raman spectroscopy, acidity measurements with IR and (31)P magic-angle-spinning NMR spectroscopy, Na(+)/H(+) exchange tests, analyses using the in situ active-site capping method, and isotope-labeling studies. A relationship between surface vacancy sites and catalytic activity has been established. CeO(2)(111) has been confirmed to be the catalytically active crystalline facet for hydrolysis. Water has been found to be associatively adsorbed on oxygen vacancy sites with medium strength, which does not lead to water dissociation to form stable hydroxides. This explains why the ceria catalyst is water-tolerant.

  13. Sub-critical water hydrolysis of hog hair for amino acid production.

    PubMed

    Esteban, M B; García, A J; Ramos, P; Márquez, M C

    2010-04-01

    A recycling method using sub-critical water hydrolysis to convert hog hair from slaughterhouses into amino acids was developed. The influence of the reaction parameters such as temperature, time of reaction and initial substrate concentration were investigated in a batch reactor. The quality and quantity of amino acids in hydrolysates were determined and 17 kinds of amino acids were obtained. Under the tested conditions, the highest amino acid yield (325 mg/g protein) was reached at an initial substrate concentration of 10 g/l, a temperature of 250 degrees C and a reaction time of 60 min. A large amount of low-molecular weight amino acids, such alanine and glycine, was observed at these operating conditions. Sub-critical water hydrolysis was confirmed as an effective and practical process to recover amino acids from hog hair waste.

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

    SciTech Connect

    Rajesh, B.; Sasirekha, N.R.; Chen, Y.-W.

    2008-03-04

    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{sup +}]/[Ti{sup 4+}] = 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{sup +}]/[Ti{sup 4+}] ratio and particle size of titania was observed.

  15. SO₃H-functionalized acidic ionic liquids as catalysts for the hydrolysis of cellulose.

    PubMed

    Liu, Yuanyuan; Xiao, Wenwen; Xia, Shuqian; Ma, Peisheng

    2013-01-30

    The conversion of cellulose into valuable chemicals to deal with the depletion of fossil fuel has got much attention. Completing the hydrolysis of cellulose under mild conditions is the key step. In this study, six kinds of SO(3)H-functionalized acidic ionic liquids were used as acid catalyst to promote the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). All of them were efficient for the hydrolysis of cellulose, with the maximum total reducing sugars (TRS) yields over 83% at 100 °C. Acidic ionic liquids with analogous structures showed similar catalytic activities. Triethyl-(3-sulfo-propyl)-ammonium hydrogen sulfate (IL-5 in this study) was the optimum ionic liquid for cellulose hydrolysis, with the maximum TRS yield at 100 °C up to 99% when the dosage used was 0.2g. In addition, the water in [BMIM]Cl had negative effect on cellulose hydrolysis. Therefore, controlling the content of water in a comparatively low level is quite necessary.

  16. Kinetics of glucose decomposition during dilute-acid hydrolysis of lignocellulosic biomass.

    PubMed

    Xiang, Qian; Lee, Yong Y; Torget, Robert W

    2004-01-01

    Recent research work in-house both at Auburn University and National Renewable Energy Laboratory has demonstrated that extremely low concentrations of acid (e.g., 0.05-0.2 wt% sulfuric acid) and high temperatures (e.g., 200-230 degrees C) are reaction conditions that can be effectively applied for hydrolysis of the cellulosic component of biomass. These conditions are far from those of the conventional dilute-acid hydrolysis processes, and the kinetic data for glucose decomposition are not currently available. We investigated the kinetics of glucose decomposition covering pH values of 1.5-2.2 and temperatures of 180-230 degrees C using glass ampoule reactors. The primary factors controlling glucose decomposition are the reaction medium, acid concentration, and temperature. Based on the experimental data, a kinetic model was developed and the best-fit kinetic parameters were determined. However, a consistent discrepancy in the rate of glucose disappearance was found between that of the model based on pure glucose data and that observed during the actual process of lignocellulosic biomass hydrolysis. This was taken as an indication that glucose recombines with acid-soluble lignin during the hydrolysis process, and this conclusion was incorporated accordingly into the overall model of glucose decomposition.

  17. Production of fuel ethanol from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation.

    PubMed

    Sun, Zhao-Yong; Tang, Yue-Qin; Iwanaga, Tomohiro; Sho, Tomohiro; Kida, Kenji

    2011-12-01

    An efficient process for the production of fuel ethanol from bamboo that consisted of hydrolysis with concentrated sulfuric acid, removal of color compounds, separation of acid and sugar, hydrolysis of oligosaccharides and subsequent continuous ethanol fermentation was developed. The highest sugar recovery efficiency was 81.6% when concentrated sulfuric acid hydrolysis was carried out under the optimum conditions. Continuous separation of acid from the saccharified liquid after removal of color compounds with activated carbon was conducted using an improved simulated moving bed (ISMB) system, and 98.4% of sugar and 90.5% of acid were recovered. After oligosaccharide hydrolysis and pH adjustment, the unsterilized saccharified liquid was subjected to continuous ethanol fermentation using Saccharomycescerevisiae strain KF-7. The ethanol concentration, the fermentation yield based on glucose and the ethanol productivity were approximately 27.2 g/l, 92.0% and 8.2 g/l/h, respectively. These results suggest that the process is effective for production of fuel ethanol from bamboo.

  18. Neutral fat hydrolysis and long-chain fatty acid oxidation during anaerobic digestion of slaughterhouse wastewater.

    PubMed

    Masse, L; Massé, D I; Kennedy, K J; Chou, S P

    2002-07-05

    Neutral fat hydrolysis and long-chain fatty acid (LCFA) oxidation rates were determined during the digestion of slaughterhouse wastewater in anaerobic sequencing batch reactors operated at 25 degrees C. The experimental substrate consisted of filtered slaughterhouse wastewater supplemented with pork fat particles at various average initial sizes (D(in)) ranging from 60 to 450 microm. At the D(in) tested, there was no significant particle size effect on the first-order hydrolysis rate. The neutral fat hydrolysis rate averaged 0.63 +/- 0.07 d(-1). LCFA oxidation rate was modelled using a Monod-type equation. The maximum substrate utilization rate (kmax) and the half-saturation concentration (Ks) averaged 164 +/- 37 mg LCFA/L/d and 35 +/- 31 mg LCFA/L, respectively. Pork fat particle degradation was mainly controlled by LCFA oxidation rate and, to a lesser extent, by neutral fat hydrolysis rate. Hydrolysis pretreatment of fat-containing wastewaters and sludges should not substantially accelerate their anaerobic treatment. At a D(in) of 450 microm, fat particles were found to inhibit methane production during the initial 20 h of digestion. Inhibition of methane production in the early phase of digestion was the only significant effect of fat particle size on anaerobic digestion of pork slaughterhouse wastewater. Soluble COD could not be used to determine the rate of lipid hydrolysis due to LCFA adsorption on the biomass.

  19. Continuous-flow electro-assisted acid hydrolysis of granular potato starch via inductive methodology.

    PubMed

    Li, Dandan; Yang, Na; Jin, Yamei; Guo, Lunan; Zhou, Yuyi; Xie, Zhengjun; Jin, Zhengyu; Xu, Xueming

    2017-08-15

    The induced electric field assisted hydrochloric acid (IEF-HCl) hydrolysis of potato starch was investigated in a fluidic system. The impact of various reaction parameters on the hydrolysis rate, including reactor number (1-4), salt type (KCl, MgCl2, FeCl3), salt concentration (3-12%), temperature (40-55°C), and hydrolysis time (0-60h), were comprehensively assessed. Under optimal conditions, the maximum reducing sugar content in the hydrolysates was 10.59g/L. X-ray diffraction suggested that the crystallinity of IEF-HCl-modified starches increased with the intensification of hydrolysis but was lower than that of native starch. Scanning electron microscopy indicated that the surface and interior regions of starch granules were disrupted by the hydrolysis. The solubility of IEF-HCl-modified starches increased compared to native starch while their swelling power decreased, contributing to a decline in paste viscosity. These results suggest that IEF is a notable potential electrotechnology to conventional hydrolysis under mild conditions without any electrode touching the subject.

  20. Brown algae hydrolysis in 1-n-butyl-3-methylimidazolium chloride with mineral acid catalyst system.

    PubMed

    Malihan, Lenny B; Nisola, Grace M; Chung, Wook-Jin

    2012-08-01

    The amenability of three brown algal species, Sargassum fulvellum, Laminaria japonica and Undaria pinnatifida, to hydrolysis were investigated using the ionic liquid (IL), 1-n-butyl-3-methylimidazolium chloride ([BMIM]Cl). Compositional analyses of the brown algae reveal that sufficient amounts of sugars (15.5-29.4 wt.%) can be recovered. Results from hydrolysis experiments show that careful selection of the type of mineral acid as catalyst and control of acid loading could maximize the recovery of sugars. Optimal reaction time and temperature were determined from the kinetic studies on the sequential reducing sugar (TRS) formation and degradation. Optimal reaction times were determined based on the extent of furfurals formation as TRS degradation products. X-ray diffraction and environmental scanning electron microscopy confirmed the suitability of [BMIM]Cl as solvent for the hydrolysis of the three brown algae. Overall results show the potential of brown algae as renewable energy resources for the production of valuable chemicals and biofuels.

  1. Black liquor-derived carbonaceous solid acid catalyst for the hydrolysis of pretreated rice straw in ionic liquid.

    PubMed

    Bai, Chenxi; Zhu, Linfeng; Shen, Feng; Qi, Xinhua

    2016-11-01

    Lignin-containing black liquor from pretreatment of rice straw by KOH aqueous solution was applied to prepare a carbonaceous solid acid catalyst, in which KOH played dual roles of extracting lignin from rice straw and developing porosity of the carbon material as an activation agent. The synthesized black liquor-derived carbon material was applied in catalytic hydrolysis of the residue solid from the pretreatment of rice straw, which was mainly composed of cellulose and hemicellulose, and showed excellent activity for the production of total reducing sugars (TRS) in ionic liquid, 1-butyl-3-methyl imidazolium chloride. The highest TRS yield of 63.4% was achieved at 140°C for 120min, which was much higher than that obtained from crude rice straw under the same reaction conditions (36.6% TRS yield). Overall, this study provides a renewable strategy for the utilization of all components of lignocellulosic biomass.

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

    PubMed

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

    2008-11-01

    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 CH2SO4 = 0.1-1M, water hyacinth intake=1-5wt%). At high acid concentrations (>0.5M), LA was the major organic acid whereas at low acid concentrations (<0.1M) and high initial intakes of water hyacinth, the formation of propionic acid instead of LA was favoured. The highest yield of LA was 53mol% (35wt%) based on the amount of C6-sugars in the water hyacinth (T=175 degrees CH2SO4 =1M , water hyacinth intake=1wt%). The LA yield as a function of the process conditions was modelled using a kinetic model originally developed for the acid-catalysed hydrolysis of cellulose and good agreement between the experimental and modelled data was obtained.

  3. Dilute acid/metal salt hydrolysis of lignocellulosics

    DOEpatents

    Nguyen, Quang A.; Tucker, Melvin P.

    2002-01-01

    A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

  4. Vacuolar Acid Hydrolysis as a Physiological Mechanism for Sucrose Breakdown 1

    PubMed Central

    Echeverria, Ed; Burns, Jacqueline K.

    1989-01-01

    Sucrose breakdown in mature acidic `Persian' limes (Citrus aurantifolia [Christm.] Swing.) occurred at a rate of 30.6 picomoles per milliliter per day during 9 weeks storage at 15°C. Neither enzyme of sucrose catabolism (sucrose synthase or acid/alkaline invertase) was present in extracts of mature storage tissue. The average vacuolar pH, estimated by direct measurement of sap from isolated vacuoles and by the methylamine method, was about 2.0 to 2.2. In vitro acid hydrolysis of sucrose at physiological concentrations in a buffered solution (pH 2.2) occurred at identical rates as in matured limes. The results indicate that sucrose breakdown in stored mature acidic limes occurs by acid hydrolysis. PMID:16666803

  5. Reduction in environmental impact of sulfuric acid hydrolysis of bamboo for production of fuel ethanol.

    PubMed

    Sun, Zhao-Yong; Tang, Yue-Qin; Morimura, Shigeru; Kida, Kenji

    2013-01-01

    Fuel ethanol can be produced from bamboo by concentrated sulfuric acid hydrolysis followed by continuous ethanol fermentation. To reduce the environmental impact of this process, treatment of the stillage, reuse of the sulfuric acid and reduction of the process water used were studied. The total organic carbon (TOC) concentration of stillage decreased from 29,688 to 269 mg/l by thermophilic methane fermentation followed by aerobic treatment. Washing the solid residue from acid hydrolysis with effluent from the biological treatment increased the sugar recovery from 69.3% to 79.3%. Sulfuric acid recovered during the acid-sugar separation process was condensed and reused for hydrolysis, resulting in a sugar recovery efficiency of 76.8%, compared to 80.1% when fresh sulfuric acid was used. After acetate removal, the condensate could be reused as elution water in the acid-sugar separation process. As much as 86.3% of the process water and 77.6% of the sulfuric acid could be recycled.

  6. Combined biomimetic and inorganic acids hydrolysis of hemicellulose in Miscanthus for bioethanol production.

    PubMed

    Guo, Bin; Zhang, Yuanhui; Ha, Suk-Jin; Jin, Yong-Su; Morgenroth, Eberhard

    2012-04-01

    Combined acid catalysis was employed as a pretreatment alternative with combined acid catalysts blending sulfuric acid with two biomimetic acids, trifluoroacetic acid (TFA) and maleic acid (MA), respectively. The influences of acid blending ratio, temperature, and acid dosage on pretreatment performance were investigated. A synergistic effect on hemicellulose decomposition was observed in the combined acid hydrolysis, which greatly increased xylose yield, although TFA/MA would induce more total phenols. Besides, combined TFA pretreatment could efficiently prevent xylose degradation. Fermentation tests of the acid-catalyzed hydrolysates with overliming showed that compared to H(2)SO(4) pretreatment, TFA and MA pretreatments improved overall ethanol yield with an increase by 27-54%. Combined acid catalysis was shown as a feasible pretreatment method for its improved sugar yield, reduced phenols production and catalyst costs.

  7. Thermal synthesis and hydrolysis of polyglyceric acid. [in orgin of life studying

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.

    1989-01-01

    Polyglyceric acid was synthesized by thermal condensation of glyceric acid at 80 C in the presence and absence of two mole percent of sulfuric acid catalyst. The acid catalyst accelerated the polymerization over 100-fold and made possible the synthesis of insoluble polymers of both L- and DL-glyceric acid by heating for less than 1 day. Racemization of L-glyceric acid yielded less than 1 percent D-glyceric acid in condensations carried out at 80 C with catalyst for 1 day and without catalyst for 12 days. The condensation of L-glyceric acid yielded an insoluble polymer much more readily than condensation of DL-glyceric acid. Studies of the hydrolysis of poly-DL-glyceric acid revealed that it was considerably more stable under mild acidic conditions compared to neutral pH. The relationship of this study to the origin of life is discussed.

  8. First Synthesis of 1,4-Dimethoxy-2-Naphthoxyacetic acid.

    PubMed

    Chinea, Kimberly; Banerjee, Ajoy K

    2015-07-01

    2-Acetyl-1-hydroxynaphthalene was converted into 1,4-dimethoxy-2-naphthoxyacetic acid in seven steps (methylation, Bayer-Villiger oxidation, hydrolysis, bromination, methylation, alkylation and hydrolysis). 2-Hydroxy-1,4-naphthoquinone on acetylation, aromatization, methylation and hydrolysis, respectively, also yielded the title compound.

  9. Hydrolysis of 4-hydroxybenzoic acid esters (parabens) and their aerobic transformation into phenol by the resistant Enterobacter cloacae strain EM.

    PubMed

    Valkova, N; Lépine, F; Valeanu, L; Dupont, M; Labrie, L; Bisaillon, J G; Beaudet, R; Shareck, F; Villemur, R

    2001-06-01

    Enterobacter cloacae strain EM was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben. It harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens. Strain EM was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mM) and in very high concentrations of methylparaben (3,000 mg liter(-1), or 19.7 mM). This strain was able to hydrolyze approximately 500 mg of methyl-, ethyl-, or propylparaben liter(-1) (3 mM) in less than 2 h in liquid culture, and the supernatant of a sonicated culture, after a 30-fold dilution, was able to hydrolyze 1,000 mg of methylparaben liter(-1) (6.6 mM) in 15 min. The first step of paraben degradation was the hydrolysis of the ester bond to produce 4-hydroxybenzoic acid, followed by a decarboxylation step to produce phenol under aerobic conditions. The transformation of 4-hydroxybenzoic acid into phenol was stoichiometric. The conversion of approximately 500 mg of parabens liter(-1) (3 mM) to phenol in liquid culture was completed within 5 h without significant hindrance to the growth of strain EM, while higher concentrations of parabens partially inhibited its growth.

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

    NASA Astrophysics Data System (ADS)

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

    2010-03-01

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

  11. Acid hydrolysis of native and annealed starches and branch-structure of their Naegeli dextrins.

    PubMed

    Nakazawa, Yuta; Wang, Ya-Jane

    2003-11-21

    Eight commercial starches, including common corn, waxy corn, wheat, tapioca, potato, Hylon V, Hylon VII, and mung bean starch, were annealed by a multiple-step process, and their gelatinization characteristics were determined. Annealed starches had higher gelatinization temperatures, reduced gelatinization ranges, and increased gelatinization enthalpies than their native starches. The annealed starches with the highest gelatinization enthalpies were subjected to acid hydrolysis with 15.3% H2SO4, and Naegeli dextrins were prepared after 10 days' hydrolysis. Annealing increased the acid susceptibility of native starches in the first (rapid) and the second (slow) phases with potato starch showing the greatest and high amylose starches showing the least changes. Starches with a larger shift in onset gelatinization temperature also displayed a greater percent hydrolysis. The increase in susceptibility to acid hydrolysis was proposed to result from defective and porous structures that resulted after annealing. Although annealing perfected the crystalline structure, it also produced void space, which led to porous structures and possible starch granule defects. The molecular size distribution and chain length distribution of Naegeli dextrins of annealed and native starches were analyzed. The reorganization of the starch molecule during annealing occurred mainly within the crystalline lamellae. Imperfect double helices in the crystalline lamellae improved after annealing, and the branch linkages at the imperfect double helices became protected by the improved crystalline structure. Therefore, more long chains were observed in the Naegeli dextrins of annealed starches than in native starches.

  12. Solid acid-catalyzed cellulose hydrolysis monitored by in situ ATR-IR spectroscopy.

    PubMed

    Zakzeski, Joseph; Grisel, Ruud J H; Smit, Arjan T; Weckhuysen, Bert M

    2012-02-13

    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 other compounds, were measured in water under ambient and elevated temperatures. A combination of spectroscopic and HPLC analysis revealed that the cellulose hydrolysis proceeds first through the disruption of the glycosidic linkages of cellulose to form smaller cellulose molecules, which are readily observed by their distinctive C-O vibrational stretches. The continued disruption of the linkages in these oligomers eventually results in the formation and accumulation of monomeric glucose. The solid-acid catalyst accelerated the isomerization of glucose to fructose, which then rapidly reacted under hydrothermal conditions to form degradation products, which included HMF, LA, formic acid, and acetic acid. The formation of these species could be suppressed by decreasing the residence time of glucose in the reactor, reaction temperature, and contact with the metal reactor. The hydrolysis of regenerated cellulose proceeded faster and under milder conditions than microcrystalline cellulose, which resulted in increased glucose yield and selectivity.

  13. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2... 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2'-(1,2-diazenediyl)bis - and...

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

    PubMed

    Uju; Goto, Masahiro; Kamiya, Noriho

    2016-08-01

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

  15. Kinetics of hyaluronan hydrolysis in acidic solution at various pH values.

    PubMed

    Tømmeraas, Kristoffer; Melander, Claes

    2008-06-01

    Hyaluronic acid (HA) was hydrolyzed using varying temperatures (40, 60, and 80 degrees C) and acid concentrations (0.0010, 0.010, 0.10, 0.50, 1.0, and 2.0 M HCl). The degradation process was monitored by determination of weight average molecular weight ( M w) by size-exclusion chromatography with online multiangle laser light scattering, refractive index, and intrinsic viscosity detectors (SEC-MALLS-RI-visc) on samples taken out continuously during the hydrolysis. SEC-MALLS-RI-visc showed that the degradation gave narrow molecular weight distributions with polydispersity indexes ( M w/ M n) of 1.3-1.7. Kinetic plots of 1/ M w versus time gave linear plots showing that acid hydrolysis of HA is a random process and that it follows a first order kinetics. For hydrolysis in HCl at 60 and 80 degrees C, it was shown that the kinetic rate constant ( k h) for the degradation depended linearly on the acid concentration. Further, the dependence of temperature on the hydrolysis in 0.1 M HCl was found to give a linear Arrhenius plot (ln k h vs 1/ T), with an activation energy ( E a) of 137 kJ/mol and Arrhenius constant ( A) of 7.86 x 10 (15) h (-1). (1)H NMR spectroscopy was used to characterize the product of extensive hydrolysis (48 h at 60 degrees C in 0.1 M HCl). No indication of de- N-acetylation of the N-acetyl glucosamine (GlcNAc) units or other byproducts were seen. Additionally, a low molecular weight HA was hydrolyzed in 0.1 M DCl for 4 h at 80 degrees C. It was shown that it was primarily the beta-(1-->4)-linkage between GlcNAc and glucuronic acid (GlcA) that was cleaved during hydrolysis at pH < p K a,GlcA. The dependence of the hydrolysis rate constant was further studied as a function of pH between -0.3 and 5. The degradation was found to be random (linear kinetic plots) over the entire pH range studied. Further, the kinetic rate constant was found to depend linearly on pH in the region -0.3 to 3. Above this pH (around the p K a of HA), the kinetic constant

  16. Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose.

    PubMed

    Zhang, Juanhua; Zhang, Beixiao; Zhang, Jingqiang; Lin, Lu; Liu, Shijie; Ouyang, Pingkai

    2010-01-01

    Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323K for 10h. X-ray diffraction (XRD) and Atomic Force Microscope (AFM) analyses revealed that the fiber surface morphology of pretreated MCC (P-MCC) were uneven and rough with the crystalline diffraction peaks of P-MCC decreased to a distinct range. The X-ray Photoelectron Spectroscopy (XPS) analysis showed that the uneven and rough surface of P-MCC could enhance the adsorption of cellulose to the molecular surface of cellulose, which is one of the key factors affecting enzymatic hydrolysis of cellulose. A reversible first order kinetics was employed to describe the adsorption kinetics of cellulase to MCC and P-MCC, and the adsorption rate constants of MCC and P-MCC were found to be 0.016, 0.024, 0.041, and 0.095, 0.149, 0.218min(-1), respectively at 278K, 293K and 308K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721kJ mol(-1). The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120h resulted in yields of glucose (7.21%), cellobiose (13.16%) and total sugars (20.37%). However, after the pretreatment with phosphoric acid, the corresponding sugar yields resulted from enzymatic hydrolysis of P-MCC were increased to 24.10%, 41.42%, and 65.52%; respectively, which were 3.34, 3.15, and 3.22 times of the sugars yields from enzymatic hydrolysis of MCC.

  17. Influence of pretreatment condition on the fermentable sugar production and enzymatic hydrolysis of dilute acid-pretreated mixed softwood.

    PubMed

    Lim, Woo-Seok; Lee, Jae-Won

    2013-07-01

    In this study, the effects of different acid catalysts and pretreatment factors on the hydrolysis of mixed softwood were investigated over a range of thermochemical pretreatments. Maleic, oxalic, and sulfuric acids were each used, under different pretreatment conditions. The most influential factor for fermentable sugar production in the dicarboxylic acid pretreatment of softwood was the pH. Reaction temperature was the next significant factor. However, during sulfuric acid pretreatment, fermentable sugar production was more dependent on reaction temperature, than time or pH. Enzymatic hydrolysis yields differed, depending on acid catalyst and pretreatment factor, regardless of lignin content in pretreated biomass. The highest enzymatic hydrolysis yield was found following maleic acid pretreatment, which reached 61.23%. The trend in enzymatic hydrolysis yields that were detected concomitantly with pretreatment condition or type of acid catalyst was closely related to the fermentable sugar production in the hydrolysate.

  18. Caffeic acid treatment alters the extracellular adenine nucleotide hydrolysis in platelets and lymphocytes of adult rats.

    PubMed

    Anwar, Javed; Spanevello, Roselia Maria; Pimentel, Victor Camera; Gutierres, Jessié; Thomé, Gustavo; Cardoso, Andreia; Zanini, Daniela; Martins, Caroline; Palma, Heloisa Einloft; Bagatini, Margarete Dulce; Baldissarelli, Jucimara; Schmatz, Roberta; Leal, Cláudio Alberto Martins; da Costa, Pauline; Morsch, Vera Maria; Schetinger, Maria Rosa Chitolina

    2013-06-01

    This study evaluated the effects of caffeic acid on ectonucleotidase activities such as NTPDase (nucleoside triphosphate diphosphohydrolase), Ecto-NPP (nucleotide pyrophosphatase/phosphodiesterase), 5'-nucleotidase and adenosine deaminase (ADA) in platelets and lymphocytes of rats, as well as in the profile of platelet aggregation. Animals were divided into five groups: I (control); II (oil); III (caffeic acid 10 mg/kg); IV (caffeic acid 50 mg/kg); and V (caffeic acid 100 mg/kg). Animals were treated with caffeic acid diluted in oil for 30 days. In platelets, caffeic acid decreased the ATP hydrolysis and increased ADP hydrolysis in groups III, IV and V when compared to control (P<0.05). The 5'-nucleotidase activity was decreased, while E-NPP and ADA activities were increased in platelets of rats of groups III, IV and V (P<0.05). Caffeic acid reduced significantly the platelet aggregation in the animals of groups III, IV and V in relation to group I (P<0.05). In lymphocytes, the NTPDase and ADA activities were increased in all groups treated with caffeic acid when compared to control (P<0.05). These findings demonstrated that the enzymes were altered in tissues by caffeic acid and this compound decreased the platelet aggregation suggesting that caffeic acid should be considered a potentially therapeutic agent in disorders related to the purinergic system.

  19. Kinetics of acid hydrolysis and reactivity of some antibacterial hydrophilic iron(II) imino-complexes

    NASA Astrophysics Data System (ADS)

    Shaker, Ali Mohamed; Nassr, Lobna Abdel-Mohsen Ebaid; Adam, Mohamed Shaker Saied; Mohamed, Ibrahim Mohamed Abdelhalim

    2015-05-01

    Kinetic study of acid hydrolysis of some hydrophilic Fe(II) Schiff base amino acid complexes with antibacterial properties was performed using spectrophotometry. The Schiff base ligands were derived from sodium 2-hydroxybenzaldehyde-5-sulfonate and glycine, L-alanine, L-leucine, L-isoleucine, DL-methionine, DL-serine, or L-phenylalanine. The reaction was studied in aqueous media under conditions of pseudo-first order kinetics. Moreover, the acid hydrolysis was studied at different temperatures and the activation parameters were calculated. The general rate equation was suggested as follows: rate = k obs [Complex], where k obs = k 2 [H+]. The evaluated rate constants and activation parameters are consistent with the hydrophilicity of the investigated complexes.

  20. Prediction of acid hydrolysis of lignocellulosic materials in batch and plug flow reactors.

    PubMed

    Jaramillo, Oscar Johnny; Gómez-García, Miguel Ángel; Fontalvo, Javier

    2013-08-01

    This study unifies contradictory conclusions reported in literature on acid hydrolysis of lignocellulosic materials, using batch and plug flow reactors, regarding the influence of the initial liquid ratio of acid aqueous solution to solid lignocellulosic material on sugar yield and concentration. The proposed model takes into account the volume change of the reaction media during the hydrolysis process. An error lower than 8% was found between predictions, using a single set of kinetic parameters for several liquid to solid ratios, and reported experimental data for batch and plug flow reactors. For low liquid-solid ratios, the poor wetting and the acid neutralization, due to the ash presented in the solid, will both reduce the sugar yield. Also, this study shows that both reactors are basically equivalent in terms of the influence of the liquid to solid ratio on xylose and glucose yield.

  1. High temperature dilute acid pretreatment of coastal Bermuda grass for enzymatic hydrolysis.

    PubMed

    Redding, Arthur P; Wang, Ziyu; Keshwani, Deepak R; Cheng, Jay J

    2011-01-01

    Dilute sulfuric acid was used to pretreat coastal Bermuda grass at high temperature prior to enzymatic hydrolysis. After both pretreatment and enzymatic hydrolysis processes, the highest yield of total sugars (combined xylose and glucose) was 97% of the theoretical value. The prehydrolyzate liquor was analyzed for inhibitory compounds (furfural, hydroxymethylfurfural (HMF)) in order to assess potential risk for inhibition during the following fermentation. Accounting for the formation of the inhibitory compounds, a pretreatment with 1.2% acid at 140 °C for 30 min with a total sugar yield of 94% of the theoretical value may be more favorable for fermentation. From this study, it can be concluded that dilute sulfuric acid pretreatment can be successfully applied to coastal Bermuda grass to achieve high yields of monomeric glucose and xylose with acceptable levels of inhibitory compound formation.

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

    SciTech Connect

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

    2015-09-25

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  4. Characterization of microcrystalline cellulose prepared from lignocellulosic materials. Part I. Acid catalyzed hydrolysis.

    PubMed

    Adel, Abeer M; Abd El-Wahab, Zeinab H; Ibrahim, Atef A; Al-Shemy, Mona T

    2010-06-01

    Rice hulls (RH) and bean hulls (BH) were subjected to prehydrolysis treatments, to define the optimum conditions for producing a high percentage of hydrolyzed hemicellulose with a small or moderate degradation of the cellulosic portion. The hydrolysis experiments were performed using hydrochloric and sulfuric acids in concentrations ranging from (0.5 to 5)% (w/w) at 120 degrees C for 90 min and 10% consistency. The effects of different temperatures (80 to 120 degrees C) and time (30 to 120 min) on acid hydrolysis of lignocellulosic materials were recorded. It was found that, the optimum condition to hydrolyze the lignocellulosic materials (RH) and (BH) are 2% (w/w) of mineral acid at 120 degrees C for 90 min and 10% consistency. The cellulose crystallinity index in the different types of lignocellulosic materials with and without acid treatment, were increased from 0.32 to 0.46 in case of RH and from 0.43 to 0.61 in case of BH. Due to the lignin depolymerization during the pretreatment process, the relative absorbency of the methoxyl group and the aromatic rings bands were lowered for the pretreated than the untreated lignocellulosic materials. Also, the band at 1730 cm(-1) which is attributed to carbonyl groups of uronic acids was lowered due the hemicellulose hydrolysis.

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

    SciTech Connect

    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. 6-methyl-8-hexadecenoic acid: A novel fatty acid from the marine spongeDesmapsama anchorata.

    PubMed

    Carballeira, N M; Maldonado, M E

    1988-07-01

    The novel fatty acid 7-methyl-8-hexadecenoic (1) was identified in the marine spongeDesmapsama anchorata. Other interesting fatty acids identified were 14-methyl-8-hexadecenoic (2), better known through its methyl ester as one of the components of the sex attractant of the female dermestid beetle, and the saturated fatty acid 3-methylheptadecanoic (3), known to possess larvicidal activity. The main phospholipid fatty acids encountered inD. anchorata were palmitic (16∶0), behenic (22∶0) and 5,9-hexacosadienoic acid (26∶2), which together accounted for 50% of the total phospholipid fatty acid mixture.

  7. [Structural characterization of Astragalus polysaccharides using partial acid hydrolysis-hydrophilic interaction liquid chromatography-mass spectrometry].

    PubMed

    Liang, Tu; Fu, Qing; Xin, Huaxia; Li, Fangbing; Jin, Yu; Liang, Xinmiao

    2014-12-01

    Water-soluble polysaccharides from traditional Chinese medicine (TCM) have properties of broad-spectrum treatment and low toxicity, making them as important components in natural medicines and health products. In order to solve the problem of polysaccharides characterization caused by their complex structures, a "bottom-up" approach was developed to complete the characterization of polysaccharides from Astragalus. Firstly, Astragalus pieces were extracted with hot water and then were precipitated by ethanol to obtain Astragalus polysaccharides. Secondly, a partial acid hydrolysis method was carried out and the effects of time, acid concentration and temperature on hydrolysis were investigated. The degree of hydrolysis increased along with the increase of hydrolysis time and acid concentration. The temperature played a great role in the hydrolysis process. No hydrolysis of the polysaccharides occurred at low temperature, while the polysaccharides were almost hydrolyzed to monosaccharide at high temperature. Under the optimum hydrolysis conditions (4 h, 1.5 mol/L trifluoroacetic acid, and 80 °C), Astragalus polysaccharides were hydrolyzed to characteristic oligosaccharide fragments. At last, a hydrophilic liquid chromatography-mass spectrometry method was used for the separation and structural characterization of the polysaccharide hydrolysates. The results showed that the resulting polysaccharides were mainly 1--> 4 linear glucan, and gluco-oligosaccharides with the degrees of polymerization (DP) of 4 - 11 were obtained after partial acid hydrolysis. The significance of this study is that it is the guidance for the characterization of other TCM polysaccharides.

  8. Effects of acid-hydrolysis and hydroxypropylation on functional properties of sago starch.

    PubMed

    Fouladi, Elham; Mohammadi Nafchi, Abdorreza

    2014-07-01

    In this study, sago starch was hydrolyzed by 0.14M HCl for 6, 12, 18, and 24h, and then modified by propylene oxide at a concentration of 0-30% (v/w). The effects of hydrolysis and etherification on molecular weight distribution, physicochemical, rheological, and thermal properties of dually modified starch were estimated. Acid hydrolysis of starch decreased the molecular weight of starch especially amylopectin, but hydroxypropylation had no effect on the molecular weight distribution. The degree of Molar substitution (DS) of hydroxypropylated starch after acid hydrolysis ranged from 0.007 to 0.15. Dually modified starch with a DS higher than 0.1 was completely soluble in cold water at up to 25% concentration of the starch. This study shows that hydroxypropylation and hydrolysis have synergistic effects unlike individual modifications. Dually modified sago starch can be applied to dip-molding for food and pharmaceutical processing because of its high solubility and low tendency for retrogradation.

  9. Enhanced enzymatic hydrolysis of kenaf core using irradiation and dilute acid

    NASA Astrophysics Data System (ADS)

    Lee, Byoung-Min; Jeun, Joon-Pyo; Kang, Phil-Hyun

    2017-01-01

    This study was performed to determine the effect of electron beam dose and enzymatic hydrolysis time for production of sugar such as glucose and xylose. After kenaf core was exposed to an irradiation dose that ranged from 0 to 500 kGy, the irradiated kenaf core was treated with a 3% (v/v) sulfuric acid solution using an autoclave for 5 h at 120 °C. The pretreated kenaf core was subsequently subjected to enzymatic hydrolysis at 50 °C in a shaking water bath at 150 rpm for 12, 24, 48, and 72 h. The determined enzyme activity rates were 70 FPU (Celluclast 1.5 L) and 40 CBU (Novozyme-188). The crystallinity index decreased from 50.6% in a non-pretreated kenaf core to 27.7% in kenaf core that was subjected to the two-stage pretreatment at dose of 500 kGy. The sugar yield of the two-stage pretreated kenaf core increased with an increase in irradiation dose. The sugar yield after 72 h of enzymatic hydrolysis was 73.6% at its highest with an irradiation dose of 500 kGy. The enhancement of enzymatic hydrolysis by two-stage pretreatment was more effective than non- and single pretreatment (36.9%, 40.6% and 44.0% in non-pretreatment, electron beam and dilute acid, respectively).

  10. Surface chemical compositions and dispersity of starch nanocrystals formed by sulfuric and hydrochloric acid hydrolysis.

    PubMed

    Wei, Benxi; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2014-01-01

    Surface chemical compositions of starch nanocrystals (SNC) prepared using sulfuric acid (H2SO4) and hydrochloric acid (HCl) hydrolysis were analyzed by X-ray photoelectron spectroscopy (XPS) and FT-IR. The results showed that carboxyl groups and sulfate esters were presented in SNC after hydrolysis with H2SO4, while no sulfate esters were detected in SNC during HCl-hydrolysis. TEM results showed that, compared to H2SO4-hydrolyzed sample, a wider size distribution of SNC prepared by HCl-hydrolysis were observed. Zeta-potentials were -23.1 and -5.02 mV for H2SO4- and HCl-hydrolyzed SNC suspensions at pH 6.5, respectively. Nevertheless, the zeta-potential values decreased to -32.3 and -10.2 mV as the dispersion pH was adjusted to 10.6. After placed 48 h at pH 10.6, zeta-potential increased to -24.1 mV for H2SO4-hydrolyzed SNC, while no change was detected for HCl-hydrolyzed one. The higher zeta-potential and relative small particle distribution of SNC caused more stable suspensions compared to HCl-hydrolyzed sample.

  11. Determination of chitosan with a modified acid hydrolysis and HPLC method.

    PubMed

    Li, Bo; Zhang, Jiali; Bu, Fen; Xia, Wenshui

    2013-01-25

    Acid hydrolysis and subsequent quantification of glucosamine (GlcN) are widely used for chitosan quantification. Degradation of GlcN during chitosan hydrolysis was the main reason for the decrease of recovery, which made the method improper for the quantification of chitosan. Ten milligram of chitosan hydrolyzed with 10 mL mixed acid solution of HCl-H₃PO₄ (75:25 in molar ratio) showed the highest recovery, significantly higher than HCl hydrolysis. Further study revealed that the optimum conditions involved the hydrolysis with HCl-H₃PO₄ (4.5:1.5M) for 24 h at 110 °C. The hydrolysate was neutralized and derived with 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl) before HPLC quantification. The optimum ratio of FMOC-Cl:GlcN was 53:1, with excess FMOC-Cl induced by the high ionic strength of the solution. This quantification procedure was then validated and proved to be specific, with good linearity, accuracy, and precision, making it well-suited for the determination of chitosan.

  12. Inhibition effects of dilute-acid prehydrolysate of corn stover on enzymatic hydrolysis of Solka Floc.

    PubMed

    Kothari, Urvi D; Lee, Yoon Y

    2011-11-01

    Dilute-acid pretreatment liquor (PL) produced at NREL through a continuous screw-driven reactor was analyzed for sugars and other potential inhibitory components. Their inhibitory effects on enzymatic hydrolysis of Solka Floc were investigated. When the PL was mixed into the enzymatic hydrolysis reactor at 1:1 volume ratio, the glucan and xylan digestibility decreased by 63% and 90%, respectively. The tolerance level of the enzyme for each inhibitor was determined. Of the identified degradation components, acetic acid was found to be the strongest inhibitor for cellulase activity, as it decreased the glucan yield by 10% at 1 g/L. Among the sugars, cellobiose and glucose were found to be strong inhibitors to glucan hydrolysis, whereas xylose is a strong inhibitor to xylan hydrolysis. Xylo-oligomers inhibit xylan digestibility more strongly than the glucan digestibility. Inhibition by the PL was higher than that of the simulated mixture of the identifiable components. This indicates that some of the unidentified degradation components, originated mostly from lignin, are potent inhibitors to the cellulase enzyme. When the PL was added to a simultaneous saccharification and co-fermentation using Escherichia coli KO11, the bioprocess was severely inhibited showing no ethanol formation or cell growth.

  13. Effects of radiation, acid, and base on the extractant dihexyl-(diethylcarbamoyl)methyl) phosphonate

    SciTech Connect

    Bahner, C.T.; Shoun, R.R.; McDowell, W.J.

    1981-11-01

    The effects of exposure to gamma radiation (/sup 60/Co) and of contact with acidic and basic aqueous solutions on dihexyl((diethylcarbamoyl)methyl)phosphonate (DHDECMP) were studied. Gamma radiation decomposes DHDECMP into a variety of products. The most troublesome of those are the acidic compounds that cause problems in stripping the actinides and lanthanides from the extractant at low acid concentrations. The rate of degradation of DHDECMP by radiation is about the same or only slightly higher than that of tri-n-butyl phosphate (TBP). It is relatively easy to remove the radiation-produced impurities by equilibration (scrubbing) with sodium carbonate or sodium hydroxide or by column chromatographic methods. The hydrolysis of DHDECMP in contact with aqueous solutions containing less than 3 M HNO/sub 3/ is not more severe than that of TBP under the same conditions but is significant above that acid concentration. Hydrolysis of DHDECMP in contact with aqueous sodium hydroxide solution does occur, but it should not pose an important problem with the short contact times such as those anticipated for the removal of the radiation-induced degradation products by caustic scrubbing. Results of various chromatographic tests to characterize the degradation products of DHDECMP are also given.

  14. Adsorption of low cross-linking density hydrogel OMMT/acid hydrolysis lignin grafted polyacrylic acid for Cd (II)

    NASA Astrophysics Data System (ADS)

    Lian, Enxiao; Shi, Ruoli; Deng, Yilin; Zhu, Hongjun; Ma, Yanli

    2017-03-01

    Organic montmorillonite/acid hydrolysis lignin graft poly (acrylic acid) composite superabsorbent (LBPAA/OMMT) was prepared by radical copolymerization of acrylic acid and acid hydrolysis lignin, and OMMT was homogeneous dispersed into hydrogels of LBPAA through supersonic irradiation. Persulphate ammonium was used as an initiator, and N, N'-ethylene bis-acrylamide (MBA) as a crosslinker. Adsorption behavior of water and Cd (II) ion on LBPAA/OMMT were investigated. The biggest capacity of adsorption for Cd (II) is PAA (0.6240 mmol/g). The ΔrH0 values of PAA, LBPAA, and LBPAA/OMMT were found as 116.71, 117.8, 125.15kJ mol-1 for Cd (II), respectively. Negative values of ΔrG0 indicates the spontaneous nature of the reaction.

  15. Acid hydrolysis of crude tannins from infructescence of Platycarya strobilacea Sieb. et Zucc to produce ellagic acid.

    PubMed

    Zhang, Liangliang; Wang, Yongmei; Xu, Man

    2014-01-01

    The infructescence of Platycarya strobilacea Sieb. et Zucc is a well-known traditional medicine in China, Japan and Korea. The infructescence of P. strobilacea Sieb. et Zucc is a rich source of ellagitannins that are composed of ellagic acid (EA) and gallic acid, linked to a sugar moiety. The aim of this study was to prepare EA by acid hydrolysis of crude tannins from the infructescence of P. strobilacea Sieb. et Zucc, and establish a new technological processing method for EA. The natural antioxidant EA was prepared by using the water extraction of infructescence of P. strobilacea Sieb. et Zucc, evaporation, condensation, acid hydrolysis and prepared by the process of crystallisation. The yield percentage of EA from crude EA was more than 20% and the purity of the product was more than 98%, as identified by using HPLC. The structure was identified on the basis of spectroscopic analysis and comparison with authentic compound.

  16. Synergy of Lewis and Brønsted acids on catalytic hydrothermal decomposition of carbohydrates and corncob acid hydrolysis residues to 5-hydroxymethylfurfural

    PubMed Central

    Wang, Chao; Zhang, Liming; Zhou, Tian; Chen, Jiachuan; Xu, Feng

    2017-01-01

    5-hydroxymethylfurfural (HMF) is an important platform molecule in the synthesis of various chemicals and materials. Herein, we reported a simple and effective dehydration of glucose-based carbohydrates to HMF in a biphasic system containing cyclopentyl methyl ether as the organic phase and AlCl3 with minute amounts of HCl as co-catalysts. The results showed that the mixed catalysts had a positive synergistic catalytic effect on glucose conversion to HMF compared with single AlCl3 or HCl catalyst. For glucose, the highest HMF yield of 54.5% was achieved at 175 °C for 20 min. More importantly, the optimal catalytic system was so efficient that it achieved one of the highest reported yields of HMF (30.5%) directly from corncob acid hydrolysis residues. Thus, the catalytic system can become a promising route for effective utilization of biomass in future biorefineries. PMID:28084456

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

    PubMed

    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

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

    PubMed

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

    2015-12-01

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

  19. Spore Cortex Hydrolysis Precedes Dipicolinic Acid Release during Clostridium difficile Spore Germination

    PubMed Central

    Francis, Michael B.; Allen, Charlotte A.

    2015-01-01

    ABSTRACT Bacterial spore germination is a process whereby a dormant spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released during stage I. Thus, DPA release precedes cortex hydrolysis during B. subtilis spore germination. Here, we investigated the timing of DPA release and cortex hydrolysis during Clostridium difficile spore germination and found that cortex hydrolysis precedes DPA release. Inactivation of either the bile acid germinant receptor, cspC, or the cortex hydrolase, sleC, prevented both cortex hydrolysis and DPA release. Because both cortex hydrolysis and DPA release during C. difficile spore germination are dependent on the presence of the germinant receptor and the cortex hydrolase, the release of DPA from the core may rely on the osmotic swelling of the core upon cortex hydrolysis. These results have implications for the hypothesized glycine receptor and suggest that the initiation of germinant receptor-mediated C. difficile spore germination proceeds through a novel germination pathway. IMPORTANCE Clostridium difficile infects antibiotic-treated hosts and spreads between hosts as a dormant spore. In a host, spores germinate to the vegetative form that produces the toxins necessary for disease. C. difficile spore germination is stimulated by certain bile acids and glycine. We recently identified the bile acid germinant receptor as the germination-specific, protease-like CspC. CspC is likely cortex localized, where it can transmit the bile acid signal to the cortex hydrolase, SleC. Due to the differences in location of CspC compared to the Bacillus subtilis germinant

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    NASA Astrophysics Data System (ADS)

    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%.

  2. Development of a process for the production of L-amino-acids concentrates from microalgae by enzymatic hydrolysis.

    PubMed

    Romero García, J M; Acién Fernández, F G; Fernández Sevilla, J M

    2012-05-01

    A process for the production of l-amino-acids concentrates from microalgae biomass by enzymatic hydrolysis has been developed. The process includes pre-treatment for cell-disruption, enzymatic hydrolysis and final separation by centrifugation. Thermal and mechanical cell-disruption methods have been tested, selecting mechanical disruption using bead milling for 30 min. The enzymatic hydrolysis was done using the commercial enzymes Alcalase and Flavourzyme. Maximum hydrolysis was obtained for biomass concentrations under 270 g/l and previous additional treatment with Viscozyme, reaching a 42% hydrolysis. Repeated reaction steps increased the hydrolysis from 42% (4h) with a single step to 59% (8h) after two successive steps. Further increase of the number of steps had a meagre impact on the global yield. The process widens the portfolio of products that can be obtained from microalgae biomass and is a new possibility to enhance the economic viability of microalgae-based biofuels production processes.

  3. Gas chromatographic determination of urinary phenol conjugates after acid hydrolysis/extractive acetylation.

    PubMed

    Weber, L

    1992-02-14

    Phenolic metabolites of inhaled aromatic solvent vapours were liberated by acid hydrolysis of their urinary conjugates. Steam distillation enhanced by salting-out with MgSO4 gave good recoveries. After extractive acetylation, the derivatives of all cresols and xylenols were completely separated on a Se-54 capillary column. The overall recoveries of urinary phenols relative to the internal standard, 3-chlorophenol, were in the range 92-99%.

  4. Microwave-assisted pyrolysis of methyl ricinoleate for continuous production of undecylenic acid methyl ester (UAME).

    PubMed

    Nie, Yong; Duan, Ying; Gong, Ruchao; Yu, Shangzhi; Lu, Meizhen; Yu, Fengwen; Ji, Jianbing

    2015-06-01

    Undecylenic acid methyl ester (UAME) was continuously produced from methyl ricinoleate using a microwave-assisted pyrolysis system with atomization feeding. The UAME yield of 77 wt.% was obtained at 500°C using SiC as the microwave absorbent and heating medium. The methyl ricinoleate conversion and UAME yield from microwave-assisted pyrolysis process were higher than those from conventional pyrolysis. The effect of temperature on the pyrolysis process was also investigated. The methyl ricinoleate conversion increased but the cracking liquid yield decreased when the temperature increased from 460°C to 560°C. The maximum UAME yield was obtained at the temperature of 500°C.

  5. Hydrolysis of Indole-3-Acetic Acid Esters Exposed to Mild Alkaline Conditions 1

    PubMed Central

    Baldi, Bruce G.; Maher, Barbara R.; Cohen, Jerry D.

    1989-01-01

    Ester conjugates of indole-3-acetic acid are hydrolyzed easily in basic solutions; however, quantitative data have not been available on the relationship between pH and rate of hydrolysis of the known ester conjugates. The use of basic conditions during extraction or purification of IAA by several laboratories suggested that a more systematic analysis of this process was needed. In this report we present data indicating: (a) that measurable hydrolysis of IAA-glucose (from standard solutions) and IAA-esters (from maize kernel extracts) occurs with only a few hours of treatment at pH 9 or above; (b) that the lability of some ester conjugates is even greater than that of IAA-glucose; and (c) that ester hydrolysis of standard compounds, IAA-glucose and IAA-p-nitrophenol, occurs in the `three phase extraction system' proposed by Liu and Tillberg ([1983] Physiol Plant 57: 441-447). These data indicate that the potential for problems with inadvertent hydrolysis of ester conjugates of IAA exists even at moderate pH values and in the multiphase system where exposure to basic conditions was thought to be limited. PMID:16667049

  6. High-temperature acid hydrolysis of cellulose for alcohol fuel production

    SciTech Connect

    Wright, J.D.

    1983-04-01

    Parametric analyses of high-temperature, dilute-acid hydrolysis of cellulose were carried out to determine the effect of hydrolysis parameters and processing schemes on the selling price of ethanol, and to estimate the potential economics of such processes. Analyses were conducted using a simulation model that calculates mass and energy balances, estimates the capital cost of the plant, and determines the selling price of ethanol. All plants were designed to produce 50 million gallons per year from either a corn stover or aspen wood feedstock. The feedstock was subjected to prehydrolysis and hydrolysis to convert the cellulosic components to sugars. The sugars stream was neutralized and fermented, and the ethanol was purified by distillation. Approximately half of the selling price of ethanol is due to capital-related charges and half to operating costs (primarily feedstock costs). The solids content of the processing streams is the most important processing parameter. Xylose fermentation has the potential to further reduce the cost of ethanol by 30%. Sales of furfural and lignin by-products could significantly reduce the selling price of ethanol if markets are available. The price of ethanol was not greatly affected by prehydrolysis, unreacted solids recycle, or small changes in hydrolysis conditions. The predicted selling price of $1.50/gallon, while subject to an uncertainty of approximately +- 30%, is of the same magnitude as that for ethanol produced from corn or petrochemical feedstocks.

  7. Preparation of crystalline starch nanoparticles using cold acid hydrolysis and ultrasonication.

    PubMed

    Kim, Hee-Young; Park, Dong June; Kim, Jong-Yea; Lim, Seung-Taik

    2013-10-15

    Waxy maize starch in an aqueous sulfuric acid solution (3.16 M, 14.7% solids) was hydrolyzed for 2-6 days, either isothermally at 40 °C or 4 °C, or at cycled temperatures of 4 and 40 °C (1 day each). The starch hydrolyzates were recovered as precipitates after centrifuging the dispersion (10,000 rpm, 10 min). The yield of starch hydrolyzates depended on the hydrolysis temperature and time, which varied from 6.8% to 78%. The starch hydrolyzed at 40 °C or 4/40 °C exhibited increased crystallinity determined by X-ray diffraction analysis, but melted in broader temperature range (from 60 °C to 110 °C). However, the starch hydrolyzed at 4 °C displayed the crystallinity and melting endotherm similar to those of native starch. The starch hydrolyzates recovered by centrifugation were re-dispersed in water (15% solids), and the dispersion was treated by an ultrasonic treatment (60% amplitude, 3min). The ultrasonication effectively fragmented the starch hydrolyzates to nanoparticles. The hydrolyzates obtained after 6 days of hydrolysis were more resistant to the ultrasonication than those after 2 or 4 days, regardless of hydrolysis temperatures. The starch nanoparticles could be prepared with high yield (78%) and crystallinity by 4 °C hydrolysis for 6 days followed by ultrasonication. Scanning electron microscopy revealed that the starch nanoparticles had globular shapes with diameters ranging from 50 to 90 nm.

  8. Effect of acid hydrolysis on morphology, structure and digestion property of starch from Cynanchum auriculatum Royle ex Wight.

    PubMed

    Wang, Xingchi; Wen, Fanting; Zhang, Shurong; Shen, Ruru; Jiang, Wei; Liu, Jun

    2017-03-01

    Effect of acid hydrolysis on the morphology, structure and digestion property of starch from Cynanchum auriculatum Royle ex Wight was investigated in this study. The hydrolysis degree of C. auriculatum starch rapidly increased to 63.69% after 4days and reached 78.67% at the end of 9days. Morphology observation showed that the starch granules remained intact during the first 4days of hydrolysis. However, serious erosion phenomenon was observed after 5days and starch granules completely fell into pieces after 7days. During acid hydrolysis process, the crystal type of hydrolyzed starch changed from original CB-type to final A-type. Small-angle X-ray scattering patterns showed the semi-crystalline growth rings started to be hydrolyzed after 4days. The proportions of single helix and amorphous components as well as amylose content in starch gradually decreased, whereas the proportion of double helix components continuously increased during acid hydrolysis. However, the contents of rapidly digestible starch, slowly digestible starch and resistant starch were almost constant during acid hydrolysis process, indicating the in vitro digestion property of C. auriculatum starch was not affected by acid hydrolysis. Our results provided novel information on the inner structure of C. auriculatum starch granules.

  9. Rapid online nonenzymatic protein digestion combining microwave heating acid hydrolysis and electrochemical oxidation.

    PubMed

    Basile, Franco; Hauser, Nicolas

    2011-01-01

    We report an online nonenzymatic method for site-specific digestion of proteins to yield peptides that are well suited for collision-induced dissociation tandem mass spectrometry. The method combines online microwave heating acid hydrolysis at aspartic acid and online electrochemical oxidation at tryptophan and tyrosine. The combined microwave/electrochemical digestion is reproducible and produces peptides with an average sequence length of 10 amino acids. This peptide length is similar to the average peptide length of 9 amino acids obtained by digestion of proteins with the enzyme trypsin. As a result, the peptides produced by this novel nonenzymatic digestion method, when analyzed by electrospray ionization mass spectrometry, produce protonated molecules with mostly +1 and +2 charge states. The combination of these two nonenzymatic methods overcomes shortcomings with each individual method in that (i) peptides generated by the microwave-hydrolysis method have an average amino acid length of 16 amino acids and (ii) the electrochemical-cleavage method is unable to reproducibly digest proteins with molecular masses above 4 kDa. Preliminary results are presented on the application and utility of this rapid online digestion (total of 6 min of digestion time) on a series of standard peptides and proteins as well as an Escherichia coli protein extract.

  10. Effects of high-melting methyl esters on crystallization properties of fatty acid methyl ester mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is a renewable alternative diesel fuel made from vegetable oils and animal fats. The most common form of biodiesel in the United States are fatty acid methyl esters (FAME) from soybean, canola, and used cooking oils, waste greases, and tallow. Cold flow properties of biodiesel depend on th...

  11. Determination of the main hydrolysis product of O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate, ethyl methylphosphonic acid, in human serum.

    PubMed

    Katagi, M; Nishikawa, M; Tatsuno, M; Tsuchihashi, H

    1997-02-21

    For the unequivocal proof of the use of a nerve agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), a rapid, accurate and sensitive method which allows us to identify its main hydrolysis product ethyl methylphosphonic acid (EMPA) in human serum was explored by GC-MS. GC-MS analysis was performed after solvent extraction with acetonitrile in acidic conditions from the serum sample, which was previously deproteinized by micro-ultrafiltration, and subsequent tert.-butyldimethylsilyl derivatization with N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) with 1% tert.-butyldimethylsilyl chloride (t-BDMSC). Linear calibration curves were obtained in the concentration range from 50 to 500 ng/ml for EMPA in the full-scan EI mode and from 5 to 50 ng/ml for EMPA in the SIM EI mode. The relative standard deviation obtained at a sample concentration of 50 ng/ml was 8.4% in the full-scan mode and 7.3% in the SIM mode. Upon applying the full-scan EI and CI mode, 40 ng/ml and 80 ng/ml were the detection limits. Using the SIM-EI mode, in which the ion at m/z 153 was chosen, the limit was 3 ng/ml.

  12. 76 FR 41135 - 2-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2-propenoic acid and sodium 2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-13

    ... and sodium 2-methyl-2- -1- propanesulfonate (1:1), peroxydisulfuric acid ( 202) sodium salt (1:2...-Propenoic acid, 2-methyl-, phenylmethyl ester, polymer with 2-propenoic acid and sodium 2-methyl- 2- -1-propanesulfonate (1:1), peroxydisulfuric acid ( 202) sodium salt (1:2)-initiated (also known here as: ``the...

  13. Stagewise dilute-acid pretreatment and enzyme hydrolysis of distillers' grains and corn fiber.

    PubMed

    Noureddini, Hossein; Byun, Jongwon; Yu, Ta-Jen

    2009-11-01

    Distillers' grains and corn fiber are the coproducts of the corn dry grind and wet milling industries, respectively. Availability of distillers' grains and corn fiber at the ethanol plant and their high levels of lignocellulosic material make these coproducts attractive feedstocks for conversion to ethanol. In this study, dilute sulfuric acid hydrolysis of these coproducts was investigated in a multistage scheme. After the completion of each pretreatment stage, the liquid substrate was separated and reused in the succeeding pretreatment stage with a fresh substrate. The substrate from each stage was also subjected to enzyme hydrolysis in a separate experiment. The sulfuric acid concentration and the substrate loading were maintained at 1.0 vol% and 15.0 wt.%, respectively, and the temperature was maintained at 120 degrees C in all the experiments. Experiments were also performed to study the effect of removing oil from the samples prior to the pretreatment. The highest concentration of monomeric sugars (MS) was observed when three stages of pretreatment were followed by the enzyme reaction. The enzyme hydrolysis of the three-stage pretreated dried distillers' grains and corn fiber yielded 122.6 +/- 5.8 and 184.5 +/- 4.1 mg/mL of MS, respectively. The formation of inhibitory products was also monitored.

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  15. Sulfuric acid pretreatment and enzymatic hydrolysis of photoperiod sensitive sorghum for ethanol production.

    PubMed

    Xu, Feng; Shi, Yong-Cheng; Wu, Xiaorong; Theerarattananoon, Karnnalin; Staggenborg, Scott; Wang, Donghai

    2011-05-01

    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.

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

    SciTech Connect

    F Xu; Y Shi; X Wu

    2011-12-31

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

  17. Value of Coproduction of Ethanol and Furfural from Acid Hydrolysis Processes

    SciTech Connect

    Parker, S.; Calnon, M.; Feinberg, D.; Power, A.; Weiss, L.

    1984-05-01

    In the acid hydrolysis of a cellulosic feedstock (wood, wood wastes, or crop residues), up to 3.65 lb of furfural may be coproduced with each gallon of ethanol for only the cost of recovering and purifying it. Each plant producing 50 x 106 gal/yr of ethanol would produce an amount of by-product furfural equal to the total current domestic production. Thus, the need arises for investigation into potentially suitable processes for deriving profitable end products from furfural and thus expanding the market. The objectives of this study were to determine the economic potential of five selected, large volume derivatives of furfural that could displace hydrocarbon-based chemicals, and the consequent value of furfural as a by-product to the cellulose hydrolysis process of ethanol production.

  18. Alcohol fermentation of sweet potato. 1. Acid hydrolysis and factors involved

    SciTech Connect

    Azhar, A.; Hamdy, M.K.

    1981-04-01

    Factors affecting acid hydrolysis of sweet potato powder (SPP) to fermentable sugars were examined. These include HCl concentration, temperature, time, and levels of SPP. Maximum reducing sugar, reported as dextrose equivalent (DE), was detected after 24 min hydrolysis (1% SPP) in 0.034N HCl heated at 154 degrees celcius. These samples also had 3.43% hydroxymethylfurfural (HMF) based on dry weight. A high level of HMF (9.2%) was detected in 1% SPP heated at 154 degrees C in 0.10N HCl for 18 min. The lowest concentration of HMF formed (1.8%), at maximal DE of 61%, was established in samples containing 5% SPP and heated at 154 degrees C in 0.034N HCl for 48 min. Aqueous extracts of uncured SPP, examined by HPLC, contained glucose, fructose and sucrose, butdegreaded SPP had only glucose and fructose. Products of degraded SPP, under appropriate conditions, could be used for alcohol fermentation. (Refs. 18).

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

    PubMed

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

    2016-03-01

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

  20. Characterisation of the products from pyrolysis of residues after acid hydrolysis of Miscanthus.

    PubMed

    Melligan, F; Dussan, K; Auccaise, R; Novotny, E H; Leahy, J J; Hayes, M H B; Kwapinski, W

    2012-03-01

    Platform chemicals such as furfural and hydroxymethylfurfural are major products formed during the acid hydrolysis of lignocellulosic biomass in second generation biorefining processes. Solid hydrolysis residues (HR) can amount to 50 wt.% of the starting biomass materials. Pyrolysis of the HRs gives rise to biochar, bio-liquids, and gases. Time and temperature were variables during the pyrolysis of HRs in a fixed bed tubular reactor, and both parameters have major influences on the amounts and properties of the products. Biochar, with potential for carbon sequestration and soil conditioning, composed about half of the HR pyrolysis product. The amounts (11-20 wt.%) and compositions (up to 77% of phenols in organic fraction) of the bio-liquids formed suggest that these have little value as fuels, but could be sources of phenols, and the gas can have application as a fuel.

  1. Plantain starch granules morphology, crystallinity, structure transition, and size evolution upon acid hydrolysis.

    PubMed

    Hernández-Jaimes, C; Bello-Pérez, L A; Vernon-Carter, E J; Alvarez-Ramirez, J

    2013-06-05

    Plantain native starch was hydrolysed with sulphuric acid for twenty days. Hydrolysis kinetics was described by a logistic function, with a zero-order rate during the first seven days, followed by a slower kinetics dynamics at longer times. X-ray diffraction results revealed a that gradual increase in crystallinity occurred during the first seven days, followed by a decrease to values similar to those found in the native starch. Differential scanning calorimetry analysis suggested a sharp structure transition by the seventh day probably due to a molecular rearrangement of the starch blocklets and inhomogeneous erosion of the amorphous regions and semi crystalline lamellae. Scanning electron micrographs showed that starch granules morphology was continually degraded from an initial oval-like shape to irregular shapes due to aggregation effects. Granule size distribution broadened as hydrolysis time proceeded probably due to fragmentation and agglomeration phenomena of the hydrolysed starch granules.

  2. The enhancement of the hydrolysis of bamboo biomass in ionic liquid with chitosan-based solid acid catalysts immobilized with metal ions.

    PubMed

    Cheng, Jie; Wang, Nan; Zhao, Dezhou; Qin, Dandan; Si, Wenqing; Tan, Yunfei; Wei, Shun'an; Wang, Dan

    2016-11-01

    Three kinds of sulfonated cross-linked chitosan (SCCR) immobilized with metal ions of Cu(2+), Fe(3+) and Zn(2+) individually were synthesized and firstly used as solid acid catalysts in the hydrolysis of bamboo biomass. FTIR spectra showed that metal ions had been introduced into SCCR and the N-metal ions coordinate bound was formed. The particle sizes of these catalysts were about 500-1000μm with a pore size of 50-160μm. All of the three kinds of catalysts performed well for bamboo hydrolysis with 1-butyl-3-methyl-imidazolium chloride used as solvent. The most effective one was sulfonated cross-linked chitosan immobilized with Fe(3+) (Fe(3+)-SCCR). TRS yields were up to 73.42% for hydrolysis of bamboo powder in [C4mim]Cl with Fe(3+)-SCCR at 120°C and 20RPM after 24h. These novel chitosan-based metal ions immobilized solid acid catalysts with ionic liquids as the solvent might be promising to facilitate cost-efficient conversion of biomass into biofuels and bioproducts.

  3. 40 CFR 721.1576 - 1,3-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cyclohexyl] methyl] ester. 721.1576 Section 721.1576 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,3-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1162; CAS...

  4. 40 CFR 721.1578 - 1,4-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cyclohexyl] methyl] ester. 721.1578 Section 721.1578 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,4-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1164; CAS...

  5. 40 CFR 721.1576 - 1,3-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cyclohexyl] methyl] ester. 721.1576 Section 721.1576 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,3-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1162; CAS...

  6. 40 CFR 721.1578 - 1,4-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... cyclohexyl] methyl] ester. 721.1578 Section 721.1578 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,4-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1164; CAS...

  7. 40 CFR 721.1576 - 1,3-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... cyclohexyl] methyl] ester. 721.1576 Section 721.1576 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,3-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1162; CAS...

  8. 40 CFR 721.1578 - 1,4-Benzenedicarboxylic acid, bis[[4-[(ethenyloxy)methyl] cyclohexyl] methyl] ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... cyclohexyl] methyl] ester. 721.1578 Section 721.1578 Protection of Environment ENVIRONMENTAL PROTECTION...] methyl] ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as 1,4-benzenedicarboxylic acid, bis cyclohexyl] methyl] ester (PMN P-98-1164; CAS...

  9. Unique cellular events occurring during the initial interaction of macrophages with matrix-retained or methylated aggregated low density lipoprotein (LDL). Prolonged cell-surface contact during which ldl-cholesteryl ester hydrolysis exceeds ldl protein degradation.

    PubMed

    Buton, X; Mamdouh, Z; Ghosh, R; Du, H; Kuriakose, G; Beatini, N; Grabowski, G A; Maxfield, F R; Tabas, I

    1999-11-05

    A critical event in atherogenesis is the interaction of arterial wall macrophages with subendothelial lipoproteins. Although most studies have investigated this interaction by incubating cultured macrophages with monomeric lipoproteins dissolved in media, arterial wall macrophages encounter lipoproteins that are mostly bound to subendothelial extracellular matrix, and these lipoproteins are often aggregated or fused. Herein, we utilize a specialized cell-culture system to study the initial interaction of macrophages with aggregated low density lipoprotein (LDL) bound to extracellular matrix. The aggregated LDL remains extracellular for a relatively prolonged period of time and becomes lodged in invaginations in the surface of the macrophages. As expected, the degradation of the protein moiety of the LDL was very slow. Remarkably, however, hydrolysis of the cholesteryl ester (CE) moiety of the LDL was 3-7-fold higher than that of the protein moiety, in stark contrast to the situation with receptor-mediated endocytosis of acetyl-LDL. Similar results were obtained using another experimental system in which the degradation of aggregated LDL protein was delayed by LDL methylation rather than by retention on matrix. Additional experiments indicated the following properties of this interaction: (a) LDL-CE hydrolysis is catalyzed by lysosomal acid lipase; (b) neither scavenger receptors nor the LDL receptor appear necessary for the excess LDL-CE hydrolysis; and (c) LDL-CE hydrolysis in this system is resistant to cellular potassium depletion, which further distinguishes this process from receptor-mediated endocytosis. In summary, experimental systems specifically designed to mimic the in vivo interaction of arterial wall macrophages with subendothelial lipoproteins have demonstrated an initial period of prolonged cell-surface contact in which CE hydrolysis exceeds protein degradation.

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

    NASA Astrophysics Data System (ADS)

    Fatmawati, Akbarningrum; Agustriyanto, Rudy

    2015-12-01

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

  11. 4-(2-Methyl-4-chlorophenoxy) butyric acid (MCPB)

    Integrated Risk Information System (IRIS)

    4 - ( 2 - Methyl - 4 - chlorophenoxy ) butyric acid ( MCPB ) ; CASRN 94 - 81 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Hea

  12. 2-(2-Methyl-4-chlorophenoxy)propionic acid (MCPP)

    Integrated Risk Information System (IRIS)

    2 - ( 2 - Methyl - 4 - chlorophenoxy ) propionic acid ( MCPP ) ; CASRN 93 - 65 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( H

  13. Cinnamyl alcohols and methyl esters of fatty acids from Wedelia prostrata callus cultures.

    PubMed

    El-Mawla, Ahmed M A Abd; Farag, Salwa F; Beuerle, Till

    2011-01-01

    Two methyl esters of fatty acids, namely octadecanoic acid methyl ester (methyl stearate) and hexadecanoic acid methyl ester (methyl palmitate), in addition to four cinnamyl alcohol derivatives, sinapyl alcohol, coniferyl alcohol, p-coumaryl alcohol and coniferyl alcohol 4-O-glucoside (coniferin), were isolated from callus cultures of Wedelia prostrata. The structure of coniferin was established by spectroscopic and chemical methods, while the other compounds were identified by gas chromatography-mass spectrometry and thin layer chromatography in comparison with standards.

  14. Comparative study on two-step concentrated acid hydrolysis for the extraction of sugars from lignocellulosic biomass.

    PubMed

    Wijaya, Yanuar Philip; Putra, Robertus Dhimas Dhewangga; Widyaya, Vania Tanda; Ha, Jeong-Myeong; Suh, Dong Jin; Kim, Chang Soo

    2014-07-01

    Among all the feasible thermochemical conversion processes, concentrated acid hydrolysis has been applied to break the crystalline structure of cellulose efficiently and scale up for mass production as lignocellulosic biomass fractionation process. Process conditions are optimized by investigating the effect of decrystallization sulfuric acid concentration (65-80 wt%), hydrolysis temperature (80°C and 100°C), hydrolysis reaction time (during two hours), and biomass species (oak wood, pine wood, and empty fruit bunch (EFB) of palm oil) toward sugar recovery. At the optimum process condition, 78-96% sugars out of theoretically extractable sugars have been fractionated by concentrated sulfuric acid hydrolysis of the three different biomass species with 87-90 g/L sugar concentration in the hydrolyzate and highest recalcitrance of pine (softwood) was determined by the correlation of crystallinity index and sugar yield considering reaction severity.

  15. Improving bioethanol production from olive pruning biomass by deacetylation step prior acid hydrolysis and fermentation processes.

    PubMed

    Moya, Alberto J; Peinado, Silvia; Mateo, Soledad; Fonseca, Bruno G; Sánchez, Sebastián

    2016-11-01

    In order to produce bioethanol from olive tree pruning biomass, deacetylation was performed employing sodium hydroxide. Optimal conditions were determined using experimental design techniques. The highest acetic acid removal (3.8g/dm(3)), obtained by response surface methodology, was at optimum pretreatment conditions of temperature 60°C, 0.8% NaOH and residence time 60min. After oxalic acid hydrolysis of pretreated biomass, the hydrolysates were directly used for ethanol production without further detoxification process. Ethanol yields ranged from 0.19 to 0.45g/g, reaching the maximum yield value when pretreatment was carried out at 130°C with 100mM oxalic acid, involving a combined severity factor (CSF) of 1.05. The highest ethanol concentration obtained from pretreated biomass was 6.2g/dm(3) at 150°C, using 75mM of oxalic acid (CSF=1.53).

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

    PubMed

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

    2015-02-01

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

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

    PubMed

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

    2010-12-01

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

  18. Effects of dilute acid pretreatment conditions on enzymatic hydrolysis monomer and oligomer sugar yields for aspen, balsam, and switchgrass.

    PubMed

    Jensen, Jill R; Morinelly, Juan E; Gossen, Kelsey R; Brodeur-Campbell, Michael J; Shonnard, David R

    2010-04-01

    The effects of dilute acid hydrolysis conditions were investigated on total sugar (glucose and xylose) yields after enzymatic hydrolysis with additional analyses on glucose and xylose monomer and oligomer yields from the individual hydrolysis steps for aspen (a hardwood), balsam (a softwood), and switchgrass (a herbaceous energy crop). The results of this study, in the form of measured versus theoretical yields and a severity analysis, show that for aspen and balsam, high dilute acid hydrolysis xylose yields were obtainable at all acid concentrations (0.25-0.75 wt.%) and temperatures (150-175 degrees C) studied as long as reaction time was optimized. Switchgrass shows a relatively stronger dependence on dilute acid hydrolysis acid concentration due to its higher neutralizing mineral content. Maximum total sugar (xylose and glucose; monomer plus oligomer) yields post-enzymatic hydrolysis for aspen, balsam, and switchgrass, were 88.3%, 21.2%, and 97.6%, respectively. In general, highest yields of total sugars (xylose and glucose; monomer plus oligomer) were achieved at combined severity parameter values (log CS) between 2.20 and 2.40 for the biomass species studied.

  19. Hydroxycinnamoylmalic acids and their methyl esters from pear (Pyrus pyrifolia Nakai) fruit peel.

    PubMed

    Lee, Ki Hoon; Cho, Jeong-Yong; Lee, Hyoung Jae; Ma, Young-Kyu; Kwon, Joseph; Park, Seong Hwa; Lee, Sang-Hyun; Cho, Jeong An; Kim, Wol-Soo; Park, Keun-Hyung; Moon, Jae-Hak

    2011-09-28

    Two novel caffeoylmalic acid methyl esters, 2-O-(trans-caffeoyl)malic acid 1-methyl ester (6) and 2-O-(trans-caffeoyl)malic acid 4-methyl ester (7), were isolated from pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit peels. In addition, 5 known hydroxycinnamoylmalic acids and their methyl esters were identified: 2-O-(trans-coumaroyl)malic acid (1), 2-O-(cis-coumaroyl)malic acid (2), 2-O-(cis-coumaroyl)malic acid 1-methyl ester (3), 2-O-(trans-coumaroyl)malic acid 1-methyl ester (4), and 2-O-(trans-caffeoyl)malic acid (phaselic acid, 5). The chemical structures of these compounds were determined by spectroscopic data from ESI MS and NMR. Of all the isolated compounds, five hydroxycinnamoylmalic acids and their methyl esters (2-4, 6, 7) were identified in the pear for the first time.

  20. Optimization of the Hydrolysis of Safflower Oil for the Production of Linoleic Acid, Used as Flavor Precursor

    PubMed Central

    Aziz, Marya; Husson, Florence; Kermasha, Selim

    2015-01-01

    Commercial lipases, from porcine pancreas (PPL), Candida rugosa (CRL), and Thermomyces lanuginosus (Lipozyme TL IM), were investigated in terms of their efficiency for the hydrolysis of safflower oil (SO) for the liberation of free linoleic acid (LA), used as a flavor precursor. Although PPL, under the optimized conditions, showed a high degree of hydrolysis (91.6%), its low tolerance towards higher substrate concentrations could limit its use for SO hydrolysis. In comparison to the other investigated lipases, Lipozyme TL IM required higher amount of enzyme and an additional 3 h of reaction time to achieve its maximum degree of SO hydrolysis (90.2%). On the basis of the experimental findings, CRL was selected as the most appropriate biocatalyst, with 84.1% degree of hydrolysis. The chromatographic analyses showed that the CRL-hydrolyzed SO is composed mainly of free LA. PMID:26904663

  1. Optimization of the Hydrolysis of Safflower Oil for the Production of Linoleic Acid, Used as Flavor Precursor.

    PubMed

    Aziz, Marya; Husson, Florence; Kermasha, Selim

    2015-01-01

    Commercial lipases, from porcine pancreas (PPL), Candida rugosa (CRL), and Thermomyces lanuginosus (Lipozyme TL IM), were investigated in terms of their efficiency for the hydrolysis of safflower oil (SO) for the liberation of free linoleic acid (LA), used as a flavor precursor. Although PPL, under the optimized conditions, showed a high degree of hydrolysis (91.6%), its low tolerance towards higher substrate concentrations could limit its use for SO hydrolysis. In comparison to the other investigated lipases, Lipozyme TL IM required higher amount of enzyme and an additional 3 h of reaction time to achieve its maximum degree of SO hydrolysis (90.2%). On the basis of the experimental findings, CRL was selected as the most appropriate biocatalyst, with 84.1% degree of hydrolysis. The chromatographic analyses showed that the CRL-hydrolyzed SO is composed mainly of free LA.

  2. Hydrolysis of dilute acid pretreated mixed hardwood and purified microcrystalline cellulose by cell-free broth from Clostridium thermocellum

    SciTech Connect

    Lynd, L.R.; Grethlein, H.E.

    1987-01-01

    The cellulase activity in cell-free broths from Clostridium thermocellum is examined on both dilute-acid-pretreated mixed hardwood (90% maple, 10% birch) and Avicel. Experiments were conducted in vitro in order to distinguish properties of the cellulase from properties of the organism and to evaluate the effectiveness of C. thermocellum cellulase in the hydrolysis of a naturally occurring, lignin-containing substrate. The results obtained establish that essentially quantitative hydrolysis of cellulose from pretreated mixed hardwood is possible using this enzyme system. Pretreatment with 1% H/sub 2/SO/sub 4/ and a 9-s residence time at 220, 210, 200, and 180/sup 0/C allowed yields after enzymatic hydrolysis (percentage of glucan solubilized/glucan potentially solubilized) of 97.8, 86.1, 82.0, and 34.6%, respectively. Enzymatic hydrolysis of mixed hardwood with no pretreatment resulted in a yield of 10.1%. Hydrolysis yields of greater than 95% were obtained from 0.6 g/l mixed hardwood pretreated at 220/sup 0/C in 7 hours at broth strengths of 60 and 80% (v/v) and in approximately 48 hours with 33% broth. Hydrolysis of pretreated mixed hardwood is compared to hydrolysis of Avicel. The initial rate of Avicel hydrolysis saturates with respect to enzyme, whereas the initial rate of hydrolysis of pretreated wood is proportional to the amount of enzyme present. Initial hydrolysis rates for pretreated wood and Avicel at 0.6 g/l are greater for wood at low broth dilutions (1.25:1 to 5:1) by up to 2.7-fold and greater for Avicel at high broth dilutions (5:1 to 50:1) by up to 4.3-fold. Maximum rates of hydrolysis are achieved at less than 2 g substrate/liter for both pretreated wood and Avicel).

  3. Effect of acid hydrolysis on regenerated kenaf core membrane produced using aqueous alkaline-urea systems.

    PubMed

    Padzil, Farah Nadia Mohammad; Zakaria, Sarani; Chia, Chin Hua; Jaafar, Sharifah Nabihah Syed; Kaco, Hatika; Gan, Sinyee; Ng, Peivun

    2015-06-25

    Bleached kenaf core pulps (BKC) were hydrolyzed in H2SO4 (0.5M) at different time (0min to 90min) at room temperature. After the hydrolysis process, the viscosity average molecular weight (Mŋ) for BKC sample has reduced from 14.5×10(4) to 2.55×10(4). The hydrolyzed BKC was then dissolved in NaOH:urea:water and in LiOH:urea:water mixed solvent at the ratio of 7:12:81 and 4.6:15:80.4, respectively. The increased in hydrolysis time has decreased Mŋ of cellulose leading to easy dissolution process. Higher porosity and transparency with lower crystallinity index (CrI) of regenerated membrane produced can be achieved as the Mŋ reduced. The properties of membrane were observed through FESEM, UV-vis spectrophotometer and XRD. This study has proven that acid hydrolysis has reduced the Mŋ of cellulose, thus, enhanced the properties of regenerated membrane produced with assisted by alkaline/urea system.

  4. Effect of physical pretreatment on dilute acid hydrolysis of water hyacinth (Eichhornia crassipes).

    PubMed

    Harun, M Y; Dayang Radiah, A B; Zainal Abidin, Z; Yunus, R

    2011-04-01

    Effects of different physical pretreatments on water hyacinth for dilute acid hydrolysis process (121 ± 3 °C, 5% H(2)SO(4), 60 min) were comparatively investigated. Untreated sample had produced 24.69 mg sugar/g dry matter. Steaming (121 ± 3 °C) and boiling (100 ± 3 °C) for 30 min had provided 35.9% and 52.4% higher sugar yield than untreated sample, respectively. The highest sugar yield (132.96 mg sugar/g dry matter) in ultrasonication was obtained at 20 min irradiation using 100% power. The highest sugar production (155.13 mg sugar/g dry matter) was obtained from pulverized samples. Hydrolysis time was reduced when using samples pretreated by drying, mechanical comminution and ultrasonication. In most methods, prolonging the pretreatment period was ineffective and led to sugar degradations. Morphology inspection and thermal analysis had provided evidences of structure disruption that led to higher sugar recovery in hydrolysis process.

  5. 40 CFR 721.10448 - Acetic acid, hydroxy- methoxy-, methyl ester, reaction products with substituted alkylamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ester, reaction products with substituted alkylamine (generic). 721.10448 Section 721.10448 Protection... Acetic acid, hydroxy- methoxy-, methyl ester, reaction products with substituted alkylamine (generic). (a... generically as acetic acid, hydroxymethoxy-, methyl ester, reaction products with substituted alkylamine...

  6. Housefly larvae hydrolysate: orthogonal optimization of hydrolysis, antioxidant activity, amino acid composition and functional properties

    PubMed Central

    2013-01-01

    Background Antioxidant, one of the most important food additives, is widely used in food industry. At present, antioxidant is mostly produced by chemical synthesis, which would accumulate to be pathogenic. Therefore, a great interest has been developed to identify and use natural antioxidants. It was showed that there are a lot of antioxidative peptides in protein hydrolysates, possessing strong capacity of inhibiting peroxidation of macro-biomolecular and scavenging free redicals in vivo. Enzymatic hydrolysis used for preparation of antioxidative peptides is a new hot-spot in the field of natural antioxidants. It reacts under mild conditions, with accurate site-specific degradation, good repeatability and few damages to biological activity of protein. Substrates for enzymatic hydrolysis are usually plants and aqua-animals. Insects are also gaining attention because of their rich protein and resource. Antioxidative peptides are potential to be exploited as new natural antioxidant and functional food. There is a huge potential market in medical and cosmetic field as well. Result Protein hydrolysate with antioxidant activity was prepared from housefly larvae, by a two-step hydrolysis. Through orthogonal optimization of the hydrolysis conditions, the degree of hydrolysis was determined to be approximately 60%. Fractionated hydrolysate at 25 mg/mL, 2.5 mg/mL and 1 mg/mL exhibited approximately 50%, 60% and 50% of scavenging capacity on superoxide radicals, 1, 1-Diphenyl-2-picrylhydrazyl radicals and hydroxyl radicals, respectively. Hydrolysate did not exhibit substantial ion chelation. Using a linoneic peroxidation system, the inhibition activity of hydrolysate at 20 mg/mL was close to that of 20 μg/mL tertiary butylhydroquinone, suggesting a potential application of hydrolysate in the oil industry as an efficient antioxidant. The lyophilized hydrolysate presented almost 100% solubility at pH 3-pH 9, and maintained nearly 100% activity at pH 5-pH 8 at 0

  7. Microwave-assisted acid and base hydrolysis of intact proteins containing disulfide bonds for protein sequence analysis by mass spectrometry.

    PubMed

    Reiz, Bela; Li, Liang

    2010-09-01

    Controlled hydrolysis of proteins to generate peptide ladders combined with mass spectrometric analysis of the resultant peptides can be used for protein sequencing. In this paper, two methods of improving the microwave-assisted protein hydrolysis process are described to enable rapid sequencing of proteins containing disulfide bonds and increase sequence coverage, respectively. It was demonstrated that proteins containing disulfide bonds could be sequenced by MS analysis by first performing hydrolysis for less than 2 min, followed by 1 h of reduction to release the peptides originally linked by disulfide bonds. It was shown that a strong base could be used as a catalyst for microwave-assisted protein hydrolysis, producing complementary sequence information to that generated by microwave-assisted acid hydrolysis. However, using either acid or base hydrolysis, amide bond breakages in small regions of the polypeptide chains of the model proteins (e.g., cytochrome c and lysozyme) were not detected. Dynamic light scattering measurement of the proteins solubilized in an acid or base indicated that protein-protein interaction or aggregation was not the cause of the failure to hydrolyze certain amide bonds. It was speculated that there were some unknown local structures that might play a role in preventing an acid or base from reacting with the peptide bonds therein.

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

    PubMed Central

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

    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% 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. PMID:26648414

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Effect of acid concentration and pulp properties on hydrolysis reactions of mercerized sisal.

    PubMed

    Lacerda, Talita M; Zambon, Márcia D; Frollini, Elisabete

    2013-03-01

    The influence of sulfuric acid concentration (H2SO4 5-25%, 100°C), crystallinity and fibers size on the hydrolysis reaction of sisal pulps were investigated, with the goal of evaluating both the liquor composition, as an important step in the production of bioethanol, and the residual non-hydrolyzed pulp, to determine its potential application as materials. Aliquots were withdrawn from the reaction media, and the liquor composition was analyzed by HPLC. The residual non-hydrolyzed pulps were characterized by SEM, their average molar mass and crystallinity index, and their size distribution was determined using a fiber analyzer. Sulfuric acid 25% led to the highest glucose content (approximately 10gL(-1)), and this acid concentration was chosen to evaluate the influence of both the fiber size and crystallinity of the starting pulp on hydrolysis. The results showed that fibers with higher length and lower crystallinity favored glucose production in approximately 12%, with respect to the highly crystalline shorter fibers.

  11. Preparation and evaluation of lignosulfonates as a dispersant for gypsum paste from acid hydrolysis lignin.

    PubMed

    Matsushita, Yasuyuki; Yasuda, Seiichi

    2005-03-01

    In order to effectively utilize a by-product of the acid saccharification process of woody materials, the chemical conversion of guaiacyl sulfuric acid lignin (SAL), one of the acid hydrolysis lignins, into water-soluble sulfonated products with high dispersibitity was investigated. At first, SAL was phenolated (P-SAL) to enhance the solubility and reactivity. Lignosulfonates were prepared from P-SAL by three methods of hydroxymethylation followed by neutral sulfonation (two-step method), sulfomethylation (one-step method) and arylsulfonation. Surprisingly, all prepared lignosulfonates possessed 30 to 70% higher dispersibility for gypsum paste than the commercial lignosulfonate. Evaluation of the preparations for gypsum paste suggested that the higher molecular weights and sulfur contents of the preparations increased their dispersibility.

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

    PubMed Central

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

    2010-01-01

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

  13. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... AGENCY 40 CFR Part 180 Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether... residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft... permissible level for residues of methacrylic acid-methyl methacrylate-polyethylene glycol monomethyl...

  14. Kinetics and mechanism of the acid-catalyzed hydrolysis of a hypermodified nucleoside wyosine and its 5'-monophosphate.

    PubMed Central

    Golankiewicz, B; Zielonacka-Lis, E; Folkman, W

    1985-01-01

    The rates of acid-catalyzed hydrolysis of a hypermodified nucleoside, wyosine and its 5'-monophosphate were determined at various pH, temperature and buffer concentrations. The results show that despite distinct differences in structure and the glycosyl bond stability, the hydrolysis of wyosine proceeds via cleavage of the C-N bond by A-1 mechanism, analogously to simple nucleosides. Unlike majority of other monophosphates studied so far, wyosine 5'-monophosphate is not more stable than respective nucleoside. PMID:4000960

  15. Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication.

    PubMed

    Tang, Yanjun; Shen, Xiaochuang; Zhang, Junhua; Guo, Daliang; Kong, Fangong; Zhang, Nan

    2015-07-10

    Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability.

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

    PubMed

    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.

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

    PubMed Central

    2011-01-01

    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. PMID:22044685

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

    PubMed

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

    2012-11-01

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

  19. Bio-conversion of apple pomace into ethanol and acetic acid: Enzymatic hydrolysis and fermentation.

    PubMed

    Parmar, Indu; Rupasinghe, H P Vasantha

    2013-02-01

    Enzymatic hydrolysis of cellulose present in apple pomace was investigated using process variables such as enzyme activity of commercial cellulase, pectinase and β-glucosidase, temperature, pH, time, pre-treatments and end product separation. The interaction of enzyme activity, temperature, pH and time had a significant effect (P<0.05) on release of glucose. Optimal conditions of enzymatic saccharification were: enzyme activity of cellulase, 43units; pectinase, 183units; β-glucosidase, 41units/g dry matter (DM); temperature, 40°C; pH 4.0 and time, 24h. The sugars were fermented using Saccharomyces cerevisae yielding 19.0g ethanol/100g DM. Further bio-conversion using Acetobacter aceti resulted in the production of acetic acid at a concentration of 61.4g/100g DM. The present study demonstrates an improved process of enzymatic hydrolysis of apple pomace to yield sugars and concomitant bioconversion to produce ethanol and acetic acid.

  20. Assessment on proximate composition, dietary fiber, phytic acid and protein hydrolysis of germinated Ecuatorian brown rice.

    PubMed

    Cáceres, Patricio J; Martínez-Villaluenga, Cristina; Amigo, Lourdes; Frias, Juana

    2014-09-01

    Germinated brown rice (GBR) is considered healthier than brown rice (BR) but its nutritive value has been hardly studied. Since nutritive quality of GBR depends on genetic diversity and germination conditions, six Ecuadorian BR varieties were germinated at 28 and 34 ºC for 48 and 96 h in darkness and proximate composition, dietary fiber fractions, phytic acid content as well as degree of protein hydrolysis and peptide content were studied. Protein, lipids, ash and available carbohydrate ranged 7.3-10.4%, 2.0-4.0%, 0.8-1.5% and 71.6 to 84.0%, respectively, in GBR seedlings. Total dietary fiber increased during germination (6.1-13.6%), with a large proportion of insoluble fraction, while phytic acid was reduced noticeably. In general, protein hydrolysis occurred during germination was more accused at 28 ºC for 48 h. These results suggest that GBR can be consumed directly as nutritive staple food for a large population worldwide contributing to their nutritional requirements.

  1. Hydrolysis of microcrystalline cellulose using functionalized Bronsted acidic ionic liquids - A comparative study.

    PubMed

    Parveen, Firdaus; Patra, Tanmoy; Upadhyayula, Sreedevi

    2016-01-01

    Cellulose conversion to platform chemicals is required to meet the demands of increasing population and modernization of the world. Hydrolysis of microcrystalline cellulose was studied with SO3H, COOH and OH functionalized imidazole based ionic liquid using 1-butyl-3-methylimidazolium chloride [BMIM]Cl as a solvent. The influence of temperature, time, acidity of ionic liquids and catalyst loading was studied on hydrolysis reaction. The maximum %TRS yield 85%, was obtained at 100°C and 90min with 0.2g of SO3H functionalized ionic liquid. UV-vis spectroscopy using 4-nitro aniline as an indicator was performed to find out the Hammett function of ionic liquid and acidity trends are as follows: SO3H>COOH>OH. Density functional theory (DFT) calculations were performed to optimize the ionic liquid and their conjugate bases at B3LYP 6-311G++ (d, p) level using Gaussian 09 program. Theoretical findings are in agreement with the experimental results.

  2. Ultrasonic enhance acid hydrolysis selectivity of cellulose with HCl-FeCl3 as catalyst.

    PubMed

    Li, Jinbao; Zhang, Xiangrong; Zhang, Meiyun; Xiu, Huijuan; He, Hang

    2015-03-06

    The effect of ultrasonic pretreatment coupled with HCl-FeCl3 catalyst was evaluated to hydrolyze cellulose amorphous regions. The ultrasonic pretreatment leads to cavitation that affects the morphology and microstructure of fibers, enhancing the accessibility of chemical reagent to the loosened amorphous regions of cellulose. In this work, Fourier transform infrared spectroscopy (FTIR) was used to identify characteristic absorption bands of the constituents and the crystallinity was evaluated by the X-ray diffraction (XRD) technique. The results indicated that appropriate ultrasonic pretreatment assisted with FeCl3 can enhance the acid hydrolysis of amorphous regions of cellulose, thus improving the crystallinity of the remaining hydrocellulose. It was observed that sonication samples that were pretreated for 300 W and 20 min followed by acid hydrolysis had maximum of 78.9% crystallinity. The crystallinity was 9.2% higher than samples that were not subjected to ultrasound. In addition, the average fines length decreased from 49 μm to 37 μm.

  3. Biodegradation kinetics of trans-4-methyl-1-cyclohexane carboxylic acid.

    PubMed

    Paslawski, Janice C; Headley, John V; Hill, Gordon A; Nemati, Mehdi

    2009-02-01

    Naphthenic acids are a complex mixture of organic compounds which naturally occur in crude oil. Low molecular weight components of the naphthenic acids are known to be toxic in aquatic environments and there is a need to better understand the factors controlling the kinetics of their biodegradation. In this study, a relatively low molecular weight naphthenic acid compound (trans-isomer of 4-methyl-1-cyclohexane carboxylic acid) and a microbial culture developed in our laboratory were used to study the biodegradation of this naphthenic acid and to evaluate the kinetics of the process in batch cultures. The initial concentration of trans-4-methyl-1-cyclohexane carboxylic acid (50-750 mg l(-1)) did not affect the maximum specific growth rate of the bacteria at 23 degrees C (0.52 day(-1)) to the maximum biodegradable concentration (750 mg l(-1)). The maximum yield observed at this temperature and at a neutral pH was 0.21 mg of biomass per milligram of substrate. Batch experiments indicated that biodegradation can be achieved at low temperatures; however, the biodegradation rate at room temperature (23 degrees C) and neutral pH was 5 times faster than that observed at 4 degrees C. Biodegradation at various pH conditions indicated a maximum specific growth rate of 1.69 day(-1) and yield (0.41 mg mg(-1)) at a pH of 10.

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

    PubMed Central

    El-Tayeb, T.S.; Abdelhafez, A.A.; Ali, S.H.; Ramadan, E.M.

    2012-01-01

    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 120 min. 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. PMID:24031984

  5. Reversion and dehydration reactions of glucose during the dilute sulfuric acid hydrolysis of cellulose

    SciTech Connect

    Helm, R.F.

    1987-01-01

    The inaccessibility of all glycosidic bonds necessitates industrial conversion schemes which employ a dilute acid catalyst at high temperatures. Process conditions also promote further reactions of glucose via the reversion and dehydration pathways. Quantitative determination of the yields of the major reversion and dehydration products is important for understanding and predicting the amounts of these materials expected under envisioned industrial operating conditions. Microcrystalline cellulose (Avicel) was hydrolyzed with sulfuric acid (0.0-1.25 wt.%), at high temperatures (160-250/sup 0/C), and at a 3:1 liquid-to-solid ratio. The hydrolysis was monitored by evaluating the amount of cellulose remaining and the yields of glucose, solid humin, levulinic acid, formic acid, hydroxymethylfurfural (HMF), and reversion products as a function of the aforementioned reaction conditions. Analysis of the reversion products required the development of a technique for the quantitation of trace carbohydrates in complex mixtures and led to the development of a reduction/permethylation gas chromatographic procedure. Cellulose hydrolysis followed pseudo-homogeneous first-order kinetics. Glucose yield was adequately described as consecutive first-order reactions. Anhydrosugars formed via reversion followed equilibrium reaction kinetics whereas the disaccharides did not. Total reversion product yields approached 10% at 250/sup 0/C. Quantitative determination of the major dehydration products provided important information concerning the destruction of glucose. HMF was produced in up to 12% yields based on the theoretical amount of glucose available, and furfural was detected in up to 5% yields. A carbon mass balance based on the determined product yields revealed that approximately 90% of all carbon was accounted for at maximum glucose yields.

  6. Folic acid, methylation and neural tube closure in humans.

    PubMed

    Blom, Henk J

    2009-04-01

    This review provides a brief description of folate use and folic acid metabolism in relation to neural tube defect (NTD) risk. First, a meta-analysis of reduction in NTD recurrence and occurrence risk with periconceptional folic acid supplementation is presented. Second, an overview of the complex folate metabolism is given. Third, SNPs for genes involved in folate and homocysteine metabolism that have been studied in relation to NTD riskare discussed. Fourth, the questions whether folate receptor autoantibodies or hampered methylation are mechanisms underlying NTDs are briefly discussed.

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

    PubMed

    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.

  8. Behaviors and mechanism of acid dyes sorption onto diethylenetriamine-modified native and enzymatic hydrolysis starch.

    PubMed

    Wang, Zuohua; Xiang, Bo; Cheng, Rumei; Li, Yijiu

    2010-11-15

    In this paper, different starches were modified by diethylenetriamine. The native starch reacted with diethylenetriamine giving CAS, whereas the enzymatic hydrolysis starch was modified by diethylenetriamine producing CAES. Adsorption capacities of CAES for four acid dyes, namely, Acid orange 7 (AO7), Acid orange 10 (AO10), Acid green 25 (AG25) and Acid red 18 (AR18) have been determined to be 2.521, 1.242, 1.798 and 1.570 mmol g(-1), respectively. In all cases, CAES has exhibited higher sorption ability than CAS, and the increment for these dyes took the sequence of AO7 (0.944 mmol g(-1))>AO10 (0.592 mmol g(-1))>AR18 (0.411 mmol g(-1))>AG25 (0.047 mmol g(-1)). Sorption kinetics and isotherms analysis showed that these sorption processes were better fitted to pseudo-second-order equation and Langmuir equation. Chemical sorption mechanisms were confirmed by studying the effects of pH, ionic strength and hydrogen bonding. Thermodynamic parameters of these dyes onto CAES and CAS were also observed and it indicated that these sorption processes were exothermic and spontaneous in nature.

  9. Clay ingestion enhances intestinal triacylglycerol hydrolysis and non-esterified fatty acid absorption.

    PubMed

    Habold, Caroline; Reichardt, François; Le Maho, Yvon; Angel, Fabielle; Liewig, Nicole; Lignot, Jean-Hervé; Oudart, Hugues

    2009-07-01

    Consumption by animals and humans of earthy materials such as clay is often related to gut pathologies. Our aim was to determine the impact of kaolinite ingestion on glucose and NEFA transport through the intestinal mucosa. The expression of hexose transporters (Na/glucose co-transporter 1 (SGLT1), GLUT2, GLUT5) and of proteins involved in NEFA absorption (fatty acid transporter/cluster of differentiation 36 (FAT/CD36), fatty acid transport protein 4 (FATP4) and liver fatty acid binding protein (L-FABP)) was measured (1) in rats whose jejunum was perfused with a solution of kaolinite, and (2) in rats who ate spontaneously kaolinite pellets during 7 and 28 d. Also, we determined TAG and glucose absorption in the kaolinite-perfused group, and pancreatic lipase activity, gastric emptying and intestinal transit in rats orally administered with kaolinite. Glucose absorption was not affected by kaolinite perfusion or ingestion. However, kaolinite induced a significant increase in intestinal TAG hydrolysis and NEFA absorption. The cytoplasmic expression of L-FABP and FATP4 also increased due to kaolinite ingestion. NEFA may enter the enterocytes via endocytosis mainly since expression of NEFA transporters in the brush-border membrane was not affected by kaolinite. After uptake, rapid binding of NEFA by L-FABP and FATP4 could act as an intracellular NEFA buffer to prevent NEFA efflux. Increased TAG hydrolysis and NEFA absorption may be due to the adsorption properties of clay and also because kaolinite ingestion caused a slowing down of gastric emptying and intestinal transit.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Alcohol fermentation of sweet potato - 1. Acid hydrolysis and factors involved

    SciTech Connect

    Azhar, A.; Hamdy, M.K.

    1981-04-01

    Factors affecting acid hydrolysis of sweet potato powder (SPP) to fermentable sugars were examined. These include HCl concentration, temperature, time, and levels of SPP. Maximum reducing sugar, reported as dextrose equivalent (DE), was detected after 24 min hydrolysis (1% SPP) in 0.034N HCl heated at 154/degree/C. These samples also had 3.43% hydroxymethylfurfural (HMF) based on dry weight. A high level of HMF (9.2%) was detected in 1% SPP heated at 154/degree/C in 0.10N HCl for 18 min. The lowest concentration of HMF formed (1.8%), at maximal DE of 61%, was established in samples containing 5% SPP and heated at 154/degree/C in 0.034N HCl for 48 min. Aqueous extracts of uncured SPP, examined by High Performance Liquid Chromatography, contained glucose, fructose and sucrose, but degraded SPP had only glucose and fructose. Products of degraded SPP, Under appropriate conditions, could be used for alcohol fermentation. 18 refs.

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

    PubMed

    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.

  13. Combination of biological pretreatment with mild acid pretreatment for enzymatic hydrolysis and ethanol production from water hyacinth.

    PubMed

    Ma, Fuying; Yang, Na; Xu, Chunyan; Yu, Hongbo; Wu, Jianguo; Zhang, Xiaoyu

    2010-12-01

    The mild acid pretreatment and the combination of biological pretreatment by a white rot fungus Echinodontium taxodii or a brown rot fungus Antrodia sp. 5898 with mild acid pretreatment were evaluated under different pretreatment conditions for enzymatic hydrolysis and ethanol production from water hyacinth. The combined pretreatment with E. taxodii (10 days) and 0.25% H(2)SO(4) was proved to be more effective than the sole acid pretreatment. The reducing sugar yield from enzymatic hydrolysis of co-treated water hyacinth increased 1.13-2.11 fold than that of acid-treated water hyacinth at the same conditions. The following study on separate hydrolysis and fermentation with Saccharomyces cerevisiae indicated that the ethanol yield from co-treated water hyacinth achieved 0.192 g/g of dry matter, which increased 1.34-fold than that from acid-treated water hyacinth (0.146 g/g of dry matter). This suggested that the combination of biological and mild acid pretreatment is a promising method to improve enzymatic hydrolysis and ethanol production from water hyacinth with low lignin content.

  14. 40 CFR 721.2078 - 1-Piperidinecarboxylic acid, 2-[(dichloro-hydroxy-carbomonocycle)hydrazono]-, methyl ester...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...- -, methyl ester (generic). 721.2078 Section 721.2078 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2078 1-Piperidinecarboxylic acid, 2- -, methyl ester... generically identified as 1-piperidinecarboxylic acid, 2- -, methyl ester (PMN P-96-756) is subject...

  15. 40 CFR 721.2078 - 1-Piperidinecarboxylic acid, 2-[(dichloro-hydroxy-carbomonocycle)hydrazono]-, methyl ester...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...- -, methyl ester (generic). 721.2078 Section 721.2078 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2078 1-Piperidinecarboxylic acid, 2- -, methyl ester... generically identified as 1-piperidinecarboxylic acid, 2- -, methyl ester (PMN P-96-756) is subject...

  16. 40 CFR 721.2078 - 1-Piperidinecarboxylic acid, 2-[(dichloro-hydroxy-carbomonocycle)hydrazono]-, methyl ester...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...- -, methyl ester (generic). 721.2078 Section 721.2078 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2078 1-Piperidinecarboxylic acid, 2- -, methyl ester... generically identified as 1-piperidinecarboxylic acid, 2- -, methyl ester (PMN P-96-756) is subject...

  17. Simultaneous determination of enantiomerization and hydrolysis kinetic parameters of chiral N-alkylbenzothiadiazine derivatives.

    PubMed

    Carrozzo, Marina M; Cannazza, Giuseppe; Battisti, Umberto; Braghiroli, Daniela; Parenti, Carlo

    2010-05-05

    On-column stopped flow multidimensional HPLC (sfMDHPLC) and dynamic high-performance liquid chromatography were applied to investigate the influence of alkyl substituents at the sulfonamidic and amino moieties of benzothiadiazine 1,1-dioxide derivatives on hydrolysis and enantiomerization rate constants. The data obtained indicate the presence of pyrrolo substituent at the 3,4 positions on benzothiadiazine rings inhibits the hydrolysis, whereas the enantiomerization occurs in acidic medium. Hydrolysis rates are quite similar for the two benzothiadiazines methyl substituted to nitrogen at 2- and 4-positions. Conversely, enantiomerization rate of 4-N-methyl substituted is significantly higher than 2-N-methyl substituted.

  18. Application of high throughput pretreatment and co-hydrolysis system to thermochemical pretreatment. Part 1: dilute acid.

    PubMed

    Gao, Xiadi; Kumar, Rajeev; DeMartini, Jaclyn D; Li, Hongjia; Wyman, Charles E

    2013-03-01

    Because conventional approaches for evaluating sugar release from the coupled operations of pretreatment and enzymatic hydrolysis are extremely time and material intensive, high throughput (HT) pretreatment and enzymatic hydrolysis systems have become vital for screening large numbers of lignocellulosic biomass samples to identify feedstocks and/or processing conditions that significantly improve performance and lower costs. Because dilute acid pretreatment offers many important advantages in rendering biomass highly susceptible to subsequent enzymatic hydrolysis, a high throughput pretreatment and co-hydrolysis (HTPH) approach was extended to employ dilute acid as a tool to screen for enhanced performance. First, a single-step neutralization and buffering method was developed to allow effective enzymatic hydrolysis of the whole pretreated slurry. Switchgrass and poplar were then pretreated with 0.5% and 1% acid loadings at a 5% solids concentration, the resulting slurry conditioned with the buffering approach, and the entire mixture enzymatically hydrolyzed. The resulting sugar yields demonstrated that single-step neutralizing and buffering was capable of adjusting the pH as needed for enzymatic saccharification, as well as overcoming enzyme inhibition by compounds released in pretreatment. In addition, the effects of pretreatment conditions and biomass types on susceptibility of pretreated substrates to enzymatic conversion were clearly discernible, demonstrating the method to be a useful extension of HTPH systems.

  19. The acid-catalyzed hydrolysis of an α-pinene-derived organic nitrate: kinetics, products, reaction mechanisms, and atmospheric impact

    NASA Astrophysics Data System (ADS)

    Rindelaub, Joel D.; Borca, Carlos H.; Hostetler, Matthew A.; Slade, Jonathan H.; Lipton, Mark A.; Slipchenko, Lyudmila V.; Shepson, Paul B.

    2016-12-01

    The production of atmospheric organic nitrates (RONO2) has a large impact on air quality and climate due to their contribution to secondary organic aerosol and influence on tropospheric ozone concentrations. Since organic nitrates control the fate of gas phase NOx (NO + NO2), a byproduct of anthropogenic combustion processes, their atmospheric production and reactivity is of great interest. While the atmospheric reactivity of many relevant organic nitrates is still uncertain, one significant reactive pathway, condensed phase hydrolysis, has recently been identified as a potential sink for organic nitrate species. The partitioning of gas phase organic nitrates to aerosol particles and subsequent hydrolysis likely removes the oxidized nitrogen from further atmospheric processing, due to large organic nitrate uptake to aerosols and proposed hydrolysis lifetimes, which may impact long-range transport of NOx, a tropospheric ozone precursor. Despite the atmospheric importance, the hydrolysis rates and reaction mechanisms for atmospherically derived organic nitrates are almost completely unknown, including those derived from α-pinene, a biogenic volatile organic compound (BVOC) that is one of the most significant precursors to biogenic secondary organic aerosol (BSOA). To better understand the chemistry that governs the fate of particle phase organic nitrates, the hydrolysis mechanism and rate constants were elucidated for several organic nitrates, including an α-pinene-derived organic nitrate (APN). A positive trend in hydrolysis rate constants was observed with increasing solution acidity for all organic nitrates studied, with the tertiary APN lifetime ranging from 8.3 min at acidic pH (0.25) to 8.8 h at neutral pH (6.9). Since ambient fine aerosol pH values are observed to be acidic, the reported lifetimes, which are much shorter than that of atmospheric fine aerosol, provide important insight into the fate of particle phase organic nitrates. Along with rate constant

  20. Lignin hydrolysis and phosphorylation mechanism during phosphoric acid-acetone pretreatment: a DFT study.

    PubMed

    Qin, Wu; Wu, Lingnan; Zheng, Zongming; Dong, Changqing; Yang, Yongping

    2014-12-18

    The study focused on the structural sensitivity of lignin during the phosphoric acid-acetone pretreatment process and the resulting hydrolysis and phosphorylation reaction mechanisms using density functional theory calculations. The chemical stabilities of the seven most common linkages (β-O-4, β-β, 4-O-5, β-1, 5-5, α-O-4, and β-5) of lignin in H3PO4, CH3COCH3, and H2O solutions were detected, which shows that α-O-4 linkage and β-O-4 linkage tend to break during the phosphoric acid-acetone pretreatment process. Then α-O-4 phosphorylation and β-O-4 phosphorylation follow a two-step reaction mechanism in the acid treatment step, respectively. However, since phosphorylation of α-O-4 is more energetically accessible than phosphorylation of β-O-4 in phosphoric acid, the phosphorylation of α-O-4 could be controllably realized under certain operational conditions, which could tune the electron and hole transfer on the right side of β-O-4 in the H2PO4- functionalized lignin. The results provide a fundamental understanding for process-controlled modification of lignin and the potential novel applications in lignin-based imprinted polymers, sensors, and molecular devices.

  1. Hydrolysis and adsorption of cyhalofop-butyl and cyhalofop-acid on soil colloids.

    PubMed

    Pinna, Maria Vittoria; Braschi, Ilaria; Blasioli, Sonia; Gessa, Carlo E; Pusino, Alba

    2008-07-09

    A study was undertaken to investigate the stability of cyhalofop-butyl (2 R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]butylpropanoate (CyB), an aryloxyphenoxy-propionic herbicide, at different pH values. The hydrolysis of CyB was faster in nonsterile than in sterile water. In sterile medium, CyB degraded only to (2 R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propanoic acid (CyA), whereas in nonsterile water, also the metabolites (2 R)-2-[4-(4-carbamoyl-2-fluorophenoxy)phenoxy]propanoic acid (CyAA) and (2 R)-2-[4-(4-carboxyl-2-fluorophenoxy)phenoxy]propanoic acid (CyD) were detected. The adsorption of CyB onto clays, iron oxide, and dissolved organic matter (DOM), using a batch equilibrium method, was also studied. A lipophilic bond is responsible for CyB adsorption on DOM. CyB was adsorbed on Fe(III)- and Ca-clays through hydrogen bonding between the carbonyl oxygen and water surrounding the exchangeable cations. In the interlayer of K-clay, CyB was hydrolyzed to CyA, which remained adsorbed therein as a monomer. The acid CyA was adsorbed only by the Fe-oxide through complexation. The CyA-Fe-oxide complex was stable and did not undergo degradation.

  2. Methods for detecting ATP hydrolysis and nucleic acid unwinding of Japanese encephalitis virus NS3 helicase.

    PubMed

    Fang, Jin'e; Li, Huan; Peng, Guiqing; Cao, Shengbo; Zhen, F Fu; Chen, Huanchun; Song, Yunfeng

    2013-12-01

    Japanese encephalitis virus (JEV) is a mosquito-borne zoonotic pathogen that is prevalent in south-east Asia. Because there is no specific antiviral agent, JEV still causes a high rate of neurologic sequelae and mortality in humans. The helicase encoded by the NS3 gene of JEV has emerged recently as a novel antiviral target for treatment. In this study, a soluble recombinant JEV helicase protein was expressed and purified. Methods for detecting the ATP hydrolysis and nucleic acid unwinding activity were developed by luminescence and fluorescence resonance energy transfer (FRET). The concentrations of enzyme, substrate, capture strand, ATP, and divalent ions were optimised in the ATPase and helicase reactions. The feasibility of using these two methods for high-throughput screening of NS3 helicase inhibitors is discussed.

  3. Steam gasification of acid-hydrolysis biomass CAHR for clean syngas production.

    PubMed

    Chen, Guanyi; Yao, Jingang; Yang, Huijun; Yan, Beibei; Chen, Hong

    2015-03-01

    Main characteristics of gaseous product from steam gasification of acid-hydrolysis biomass CAHR have been investigated experimentally. The comparison in terms of evolution of syngas flow rate, syngas quality and apparent thermal efficiency was made between steam gasification and pyrolysis in the lab-scale apparatus. The aim of this study was to determine the effects of temperature and steam to CAHR ratio on gas quality, syngas yield and energy conversion. The results showed that syngas and energy yield were better with gasification compared to pyrolysis under identical thermal conditions. Both high gasification temperature and introduction of proper steam led to higher gas quality, higher syngas yield and higher energy conversion efficiency. However, excessive steam reduced hydrogen yield and energy conversion efficiency. The optimal value of S/B was found to be 3.3. The maximum value of energy ratio was 0.855 at 800°C with the optimal S/B value.

  4. Acidic 1,3-propanediaminetetraacetato lanthanides with luminescent and catalytic ester hydrolysis properties

    SciTech Connect

    Chen, Mao-Long; Shi, Yan-Ru; Yang, Yu-Chen; Zhou, Zhao-Hui

    2014-11-15

    In acidic solution, a serials of water-soluble coordination polymers (CPs) were isolated as zonal 1D-CPs 1,3-propanediaminetetraacetato lanthanides [Ln(1,3-H{sub 3}pdta)(H{sub 2}O){sub 5}]{sub n}·2Cl{sub n}·3nH{sub 2}O [Ln=La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5] (1,3-H{sub 4}pdta=1,3-propanediaminetetraacetic acid, C{sub 11}H{sub 18}N{sub 2}O{sub 8}) in high yields. When 1 eq. mol potassium hydroxide was added to the solutions of 1D-CPs, respectively, two 1D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 3}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=Sm, 6; Gd, 7] were isolated at room temperature and seven 2D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 2}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=La, 8; Ce, 9; Pr, 10; Nd, 11; Sm, 12; Eu, 13; Gd, 14] were isolated at 70 °C. When the crystals of 1–4 were hydrothermally heated at 180 °C with 1–2 eq. mol potassium hydroxide, four 3D-CPs [Ln(1,3-Hpdta)]{sub n}·nH{sub 2}O [Ln=La, 15; Ce, 16; Pr, 17; Nd, 18] were obtained. The two 2D-CPs [Ln(1,3-Hpdta)(H{sub 2}O)]{sub n}·4nH{sub 2}O (Sm, 19; Eu, 20) were isolated in similar reaction conditions. With the increments of pH value in the solution and reaction temperature, the structure becomes more complicated. 1–5 are soluble in water and 1 was traced by solution {sup 13}C({sup 1}H) NMR technique, the water-soluble lanthanides 1 and 5 show catalytic activity to ester hydrolysis reaction respectively, which indicate their important roles in the hydrolytic reaction. The europium complexes 13 and 20 show visible fluorescence at an excitation of 394 nm. The structure diversity is mainly caused by the variation of coordinated ligand in different pH values and lanthanide contraction effect. Acidic conditions are favorable for the isolations of lanthanide complexes in different structures and this may helpful to separate different lanthanides. The thermal stability investigations reveal that acidic condition is favorable to obtain the oxides at a lower temperature. - Graphical abstract: A series

  5. Scale-up of diluted sulfuric acid hydrolysis for producing sugarcane bagasse hemicellulosic hydrolysate (SBHH).

    PubMed

    Rodrigues, Rita de Cássia L B; Rocha, George J M; Rodrigues, Durval; Filho, Hélcio J I; Felipe, Maria das Graças A; Pessoa, Adalberto

    2010-02-01

    Sugarcane bagasse was pretreated with diluted sulfuric acid to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH). Experiments were conducted in laboratory and semi-pilot reactors to optimize the xylose recovery and to reduce the generation of sugar degradation products, as furfural and 5-hydroxymethylfurfural (HMF). The hydrolysis scale-up procedure was based on the H-Factor, that combines temperature and residence time and employs the Arrhenius equation to model the sulfuric acid concentration (100 mg(acid)/g(dm)) and activation energy (109 kJ/mol). This procedure allowed the mathematical estimation of the results through simulation of the conditions prevailing in the reactors with different designs. The SBHH obtained from different reactors but under the same H-Factor of 5.45+/-0.15 reached similar xylose yield (approximately 74%) and low concentration of sugar degradation products, as furfural (0.082 g/L) and HMF (0.0071 g/L). Also, the highest lignin degradation products (phenolic compounds) were rho-coumarilic acid (0.15 g/L) followed by ferulic acid (0.12 g/L) and gallic acid (0.035 g/L). The highest concentration of ions referred to S (3433.6 mg/L), Fe (554.4 mg/L), K (103.9 mg/L). The H-Factor could be used without dramatically altering the xylose and HMF/furfural levels. Therefore, we could assume that H-Factor was directly useful in the scale-up of the hemicellulosic hydrolysate production.

  6. Direct lactic acid fermentation of Jerusalem artichoke tuber extract using Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis.

    PubMed

    Choi, Hwa-Young; Ryu, Hee-Kyoung; Park, Kyung-Min; Lee, Eun Gyo; Lee, Hongweon; Kim, Seon-Won; Choi, Eui-Sung

    2012-06-01

    Lactic acid fermentation of Jerusalem artichoke tuber was performed with strains of Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis prior to fermentation. Some strains of L. paracasei, notably KCTC13090 and KCTC13169, could ferment hot-water extract of Jerusalem artichoke tuber more efficiently compared with other Lactobacillus spp. such as L. casei type strain KCTC3109. The L. paracasei strains could utilize almost completely the fructo-oligosaccharides present in Jerusalem artichoke. Inulin-fermenting L. paracasei strains produced c.a. six times more lactic acid compared with L. casei KCTC3109. Direct lactic fermentation of Jerusalem artichoke tuber extract at 111.6g/L of sugar content with a supplement of 5 g/L of yeast extract by L. paracasei KCTC13169 in a 5L jar fermentor produced 92.5 ce:hsp sp="0.25"/>g/L of lactic acid with 16.8 g/L fructose equivalent remained unutilized in 72 h. The conversion efficiency of inulin-type sugars to lactic acid was 98% of the theoretical yield.

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

    PubMed

    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 degree of hydrolysis (DH, DH = 48 %), Medium DH (DH = 27 %), and Low DH (DH = 23 %). The casein protein was intact. Additionally, since manufacturing of protein products may render some amino acids unavailable for utilisation in the body the digestibility and the biological value of all four protein 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 protein hydrolysates (WPH) were all significantly higher than for the casein protein, however, the degree of hydrolysis of the WPH products did not influence plasma total amino acid appearance rate (estimates of DH and 95 % confidence intervals [CI] (mol L(-1) min(-1)): High DH 0.0585 [0.0454, 0.0754], Medium DH 0.0594 [0.0495, 0.0768], Low DH 0.0560 [0.0429, 0.0732], Casein 0.0194 [0.0129, 0.0291]). The four protein products were all highly digestible, while the biological value decreased with increasing degree of hydrolysis. In conclusion, the current study does not provide evidence that the degree of whey protein hydrolysis is a strong determinant for plasma amino acid appearance rate within the studied range of hydrolysis and protein dose.

  8. Hydrolysis of tannic acid catalyzed by immobilized-stabilized derivatives of Tannase from Lactobacillus plantarum.

    PubMed

    Curiel, Jose Antonio; Betancor, Lorena; de las Rivas, Blanca; Muñoz, Rosario; Guisan, Jose M; Fernández-Lorente, Gloria

    2010-05-26

    A recombinant tannase from Lactobacillus plantarum , overexpressed in Escherichia coli , was purified in a single step by metal chelate affinity chromatography on poorly activated nickel supports. It was possible to obtain 0.9 g of a pure enzyme by using only 20 mL of chromatographic support. The pure enzyme was immobilized and stabilized by multipoint covalent immobilization on highly activated glyoxyl agarose. Derivatives obtained by multipoint and multisubunit immobilization were 500- and 1000-fold more stable than both the soluble enzyme and the one-point-immobilized enzyme in experiments of thermal and cosolvent inactivation, respectively. In addition, up to 70 mg of pure enzyme was immobilized on 1 g of wet support. The hydrolysis of tannic acid was optimized by using the new immobilized tannase derivative. The optimal reaction conditions were 30% diglyme at pH 5.0 and 4 degrees C. Under these conditions, it was possible to obtain 47.5 mM gallic acid from 5 mM tannic acid as substrate. The product was pure as proved by HPLC. On the other hand, the immobilized biocatalyst preserved >95% of its initial activity after 1 month of incubation under the optimal reaction conditions.

  9. Cassava starch maltodextrinization/monomerization through thermopressurized aqueous phosphoric acid hydrolysis.

    PubMed

    Fontana, J D; Passos, M; Baron, M; Mendes, S V; Ramos, L P

    2001-01-01

    Kinetic conditions were established for the depolymerization of cassava starch for the production of maltodextrins and glucose syrups. Thin-layer chromatography and high-performance liquid chromatography analyses corroborated that the proper H3PO4 strength and thermopressurization range (e.g., 142-170 degrees C; 2.8-6.8 atm) can be successfully explored for such hydrolytic purposes of native starch granules. Because phosphoric acid can be advantageously maintained in the hydrolysate and generates, after controlled neutralization with ammonia, the strategic nutrient triplet for industrial fermentations (C, P, N), this pretreatment strategy can be easily recognized as a recommended technology for hydrolysis and upgrading of starch and other plant polysaccharides. Compared to the classic catalysts, the mandatory desalting step (chloride removal by expensive anion-exchange resin or sulfate precipitation as the calcium-insoluble salt) can be avoided. Furthermore, properly diluted phosphoric acid is well known as an allowable additive in several popular soft drinks such as colas since its acidic feeling in the mouth is compatible and synergistic with both natural and artificial sweeteners. Glycosyrups from phosphorolyzed cassava starch have also been upgraded to high-value single-cell protein such as the pigmented yeast biomass of Xanthophyllomyces dendrorhous (Phaffia rhodozyma), whose astaxanthin (diketo-dihydroxy-beta-carotene) content may reach 0.5-1.0 mg/g of dry yeast cell. This can be used as an ideal complement for animal feeding as well as a natural staining for both fish farming (meat) and poultry (eggs).

  10. Activation Energies for an Enzyme-Catalyzed and Acid-Catalyzed Hydrolysis: An Introductory Interdisciplinary Experiment for Chemists and Biochemists.

    ERIC Educational Resources Information Center

    Adams, K. R.; Meyers, M. B.

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment in which students determine and compare the Arrhenius activation energies (Ea) for the hydrolysis of salicin. This reaction is subject to catalysis both by acid and by the enzyme emulsin (beta-d-glucoside glycohydrolase). (JN)

  11. Complexes of polyadenylic acid and the methyl esters of amino acids

    NASA Technical Reports Server (NTRS)

    Khaled, M. A.; Mulins, D. W., Jr.; Swindle, M.; Lacey, J. C., Jr.

    1983-01-01

    A study of amino acid methyl esters binding to polyadenylic acid supports the theory that the genetic code originated through weak but selective affinities between amino acids and nucleotides. NMR, insoluble complex analysis, and ultraviolet spectroscopy are used to illustrate a correlation between the hydrophybicities of A amino acids and their binding constants, which, beginning with the largest, are in the order of Phe (having nominally a hydrophobic AAA anticodon), Ile, Leu, Val and Gly (having a hydrophilic anticodon with no A). In general, the binding constants are twice the values by Reuben and Polk (1980) for monomeric AMP, which suggests that polymer amino acids are interacting with only one base. No real differences are found betwen poly A binding for free Phe, Phe methyl ester or Phe amide, except that the amide value is slightly lower.

  12. Acid esterification-alkaline transesterification process for methyl ester production from crude rubber seed oil.

    PubMed

    Thaiyasuit, Prachasanti; Pianthong, Kulachate; Worapun, Ittipon

    2012-01-01

    This study aims to examine methods and the most suitable conditions for producing methyl ester from crude rubber seed oil. An acid esterification-alkaline transesterification process is proposed. In the experiment, the 20% FFA of crude rubber seed oil could be reduced to 3% FFA by acid esterification. The product after esterified was then tranesterified by alkaline transesterification process. By this method, the maximum yield of methyl ester was 90% by mass. The overall consumption of methanol was 10.5:1 by molar ratio. The yielded methyl ester was tested for its fuel properties and met required standards. The major fatty acid methyl ester compositions were analyzed and constituted of methyl linoleate 41.57%, methyl oleate 24.87%, and methyl lonolenate 15.16%. Therefore, the cetane number of methyl ester could be estimated as 47.85, while the tested result of motor cetane number was 51.20.

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

    SciTech Connect

    Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J.

    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.

  14. Investigating the Properties and Hydrolysis Ability of Poly-Lactic Acid/Chitosan Nanocomposites Using Polycaprolactone.

    PubMed

    Trang, Nguyen Thi Thu; Chinhl, Nguyen Thuy; Thanh, Dinh Thi Mai; Hang, To Thi Xuan; Giang, Nguyen Vu; Hoang, Thai; Quan, Pham Minh; Giang, Le Duc; Thai, Nguyen Viet; Lawrence, Geoffrey

    2015-12-01

    Poly-lactic acid (PLA) has been widely applied in the medical field (in biomedicines such as medical capsules, surgical sutures and suture wounds) owing to its high biodegradability, good biocompatibility and ability to be dissolved in common solvents. Chitosan (CS) is an abundant polysaccharide and a cationic polyelectrolyte present in nature. In this study, the combination of PLA and CS has been used to form PLA/CS nanocomposites having the advantages of both the original components. To enhance the dispersibility and compatibility between PLA and CS in the PLA/CS nanocomposites, polycaprolactone (PCL) is added as a compatibilizer. The Fourier Transform Infrared spectroscopies prove the existence of the interactions of PCL with PLA and CS. A more regular dispersion of CS of 200-400 nm particle size, is observed in the PLA matrix of the PLA/CS nanocomposites containing PCL, through the Field Emission Scanning Electron Microscopy images. The appearance of one glass transition temperature (T(g)) value of PLA/CS/PCL nanocomposites occuring between the T(g) values of PLA and CS in DSC diagrams confirms the improvement in the compatibility between PLA and CS, due to the presence of PCL. The TGA result shows that PCL plays an important role in enhancing the thermal stability of PLA/CS/PCL nanocomposites. The hydrolysis of PLA/CS/PCL nanocomposites in alkaline and phosphate buffer solutions was investigated. The obtained results show that the PLA/CS/PCL nanocomposites have slower hydrolysis ability than the PLA/CS composites.

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

    PubMed Central

    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

    2016-01-01

    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. PMID:26916830

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

    PubMed

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

    2016-07-01

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

  17. A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

    PubMed

    Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

    2015-11-05

    Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed.

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

    PubMed

    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.

  19. Role of glycoconjugates of 3-methyl-4-hydroxyoctanoic acid in the evolution of oak lactone in wine during oak maturation.

    PubMed

    Wilkinson, Kerry L; Prida, Andrei; Hayasaka, Yoji

    2013-05-08

    Oak lactone is a natural component of oak wood, but it also exists in glycoconjugate precursor forms. This study concerned the role of glycoconjugates of 3-methyl-4-hydroxyoctanoic acid, specifically a galloylglucoside, glucoside, and rutinoside, in the evolution of oak lactone during cooperage and maturation. The glycoconjugate profiles of 10 French oak samples were obtained by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) using stable isotope dilution analysis. The galloylglucoside was found to be the predominant glycoconjugate precursor and ranged in concentration from 110 to 354 μg/g. Maturation trials indicated the galloylglucoside undergoes acid-catalyzed hydrolysis after extraction into wine; after 12 months of maturation, the glucoside was the most abundant precursor, present at between 2- and 11-fold higher concentrations than those observed for powdered oak. Thermal degradation of glycoconjugates was observed only when oak samples were heated at 200 °C for 30 min, demonstrating their thermal stability.

  20. An Arabidopsis thaliana methyltransferase Capable of Methylating Farnesoic Acid

    SciTech Connect

    Yang,Y.; Yuan, J.; Ross, J.; Noel, J.; Pichersky, E.

    2006-01-01

    We previously reported the identification of a new family of plant methyltransferases (MTs), named the SABATH family, that use S-adenosyl-l-methionine (SAM) to methylate a carboxyl moiety or a nitrogen-containing functional group on a diverse array of plant compounds. The Arabidopsis genome alone contains 24 distinct SABATH genes. To identify the catalytic specificities of members of this protein family in Arabidopsis, we screened recombinantly expressed and purified enzymes with a large number of potential substrates. Here, we report that the Arabidopsis thaliana gene At3g44860 encodes a protein with high catalytic specificity towards farnesoic acid (FA). Under steady-state conditions, this farnesoic acid carboxyl methyltransferase (FAMT) exhibits K{sub M} values of 41 and 71 {mu}M for FA and SAM, respectively. A three-dimensional model of FAMT constructed based upon similarity to the experimentally determined structure of Clarkia breweri salicylic acid methyltransferase (SAMT) suggests a reasonable model for FA recognition in the FAMT active site. In plants, the mRNA levels of At3g44860 increase in response to the exogenous addition of several compounds previously shown to induce plant defense responses at the transcriptional level. Although methyl farnesoate (MeFA) has not yet been detected in Arabidopsis, the presence of a FA-specific carboxyl methyltransferase in Arabidopsis capable of producing MeFA, an insect juvenile hormone made by some plants as a presumed defense against insect herbivory, suggests that MeFA or chemically similar compounds are likely to serve as new specialized metabolites in Arabidopsis.

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

    PubMed

    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.

  2. The roles of xylan and lignin in oxalic acid pretreated corncob during separate enzymatic hydrolysis and ethanol fermentation.

    PubMed

    Lee, Jae-Won; Rodrigues, Rita C L B; Kim, Hyun Joo; Choi, In-Gyu; Jeffries, Thomas W

    2010-06-01

    High yields of hemicellulosic and cellulosic sugars are critical in obtaining economical conversion of agricultural residues to ethanol. To optimize pretreatment conditions, we evaluated oxalic acid loading rates, treatment temperatures and times in a 2(3) full factorial design. Response-surface analysis revealed an optimal oxalic acid pretreatment condition to release sugar from the cob of Zea mays L. ssp. and for Pichia stipitis CBS 6054. To ferment the residual cellulosic sugars to ethanol following enzymatic hydrolysis, highest saccharification and fermentation yields were obtained following pretreatment at 180 degrees C for 50 min with 0.024 g oxalic acid/g substrate. Under these conditions, only 7.5% hemicellulose remained in the pretreated substrate. The rate of cellulose degradation was significantly less than that of hemicellulose and its hydrolysis was not as extensive. Subsequent enzymatic saccharification of the residual cellulose was strongly affected by the pretreatment condition with cellulose hydrolysis ranging between 26.0% and 76.2%. The residual xylan/lignin ratio ranged from 0.31 to 1.85 depending on the pretreatment condition. Fermentable sugar and ethanol were maximal at the lowest ratio of xylan/lignin and at high glucan contents. The model predicts optimal condition of oxalic acid pretreatment at 168 degrees C, 74 min and 0.027 g/g of oxalic acid. From these findings, we surmised that low residual xylan was critical in obtaining maximal glucose yields from saccharification.

  3. Acid activated montmorillonite as catalysts in methyl esterification reactions of lauric acid.

    PubMed

    Zatta, Leandro; Ramos, Luiz Pereira; Wypych, Fernando

    2012-01-01

    The catalytic activity of acid activated montmorillonite in the esterification of free fatty acids (FFA) is reported. Standard Montmorillonite (MMT) type STx-1 provided by the Clay Mineral Society repository was activated using phosphoric, nitric and sulphuric acids under different conditions and the resulting materials were characterized and evaluated as catalysts in the methyl esterification of lauric acid. Blank reactions carried out in the absence of any added catalyst presented conversions of 32.64, 69.79 and 79.23%, for alcohol:lauric acid molar ratios of 60:1, 12:1 and 6:1, respectively. In the presence of the untreated clay and using molar ratios of 12:1 and 6:1 with 12% of catalyst, conversions of 70.92 and 82.30% were obtained, respectively. For the acid activated clays, conversions up to 93.08% of lauric acid to methyl laurate were obtained, much higher than those observed for the thermal conversion or using untreated montmorillonite. Relative good correlations were observed between the catalytic activity and the development of acid sites and textural properties of the resulting materials. Therefore, a simple acid activation was able to improve the catalytic activity and produce clay catalysts that are environmental friendly, cost effective, noncorrosive and reusable.

  4. Improving the acidic stability of a methyl parathion hydrolase by changing basic residues to acidic residues.

    PubMed

    Huang, Lu; Wang, Ping; Tian, Jian; Jiang, Huachen; Wu, Ningfeng; Yang, Peilong; Yao, Bin; Fan, Yunliu

    2012-06-01

    The acidic stability of a methyl parathion hydrolase (Ochr-MPH) was improved by selectively changing basic amino acids to acidic ones. Mutation sites were selected based on the position-specific amino acid replacement probabilities (more than or equal to 0.2) and the entropy of each site (more than or equal to 0.8). Three mutants (K208E, K277D, and K208E/K277D) were more stable than the wild-type (WT). Their half-lives at pH 5.0 were 64, 68, 65 min, respectively, whereas that of WT was 39 min. The acidic stability of proteins may therefore be improved by changing selected basic amino acid residues to acidic ones.

  5. Selection of suitable mineral acid and its concentration for biphasic dilute acid hydrolysis of the sodium dithionite delignified Prosopis juliflora to hydrolyze maximum holocellulose.

    PubMed

    Naseeruddin, Shaik; Desai, Suseelendra; Venkateswar Rao, L

    2016-02-01

    Two grams of delignified substrate at 10% (w/v) level was subjected to biphasic dilute acid hydrolysis using phosphoric acid, hydrochloric acid and sulfuric acid separately at 110 °C for 10 min in phase-I and 121 °C for 15 min in phase-II. Combinations of acid concentrations in two phases were varied for maximum holocellulose hydrolysis with release of fewer inhibitors, to select the suitable acid and its concentration. Among three acids, sulfuric acid in combination of 1 & 2% (v/v) hydrolyzed maximum holocellulose of 25.44±0.44% releasing 0.51±0.02 g/L of phenolics and 0.12±0.002 g/L of furans, respectively. Further, hydrolysis of delignified substrate using selected acid by varying reaction time and temperature hydrolyzed 55.58±1.78% of holocellulose releasing 2.11±0.07 g/L and 1.37±0.03 g/L of phenolics and furans, respectively at conditions of 110 °C for 45 min in phase-I & 121 °C for 60 min in phase-II.

  6. Effect of the structural features of hydrochloric acid-deamidated wheat gluten on its susceptibility to enzymatic hydrolysis.

    PubMed

    Cui, Chun; Hu, Qingling; Ren, Jiaoyan; Zhao, Haifeng; You, Lijun; Zhao, Mouming

    2013-06-19

    The effect of the structural features of hydrochloric acid-deamidated wheat gluten with different degrees of deamidation (DDs) on the susceptibility to enzymatic hydrolysis by pancreatin was investigated. The wheat gluten deamidated by hydrochloric acid with a DD of 55% revealed the highest susceptibility to enzymatic hydrolysis as evaluated by the hydrolysis degree and nitrogen solubility index of the hydrolysates. An increase of peptides with MW below 3000 Da was observed as the DD increased. Raman spectra in the 1740-1800 cm⁻¹ and 521-530 cm⁻¹ range suggested that wheat gluten had taken off the deamidation with different DDs and that the disulfide bond had disrupted the sulfhydryl groups with different intensities, respectively. Results from the deconvolution of the amide I region of FTIR spectra in the 1600-1700 cm⁻¹ range showed that the content of the α-helix decreased and that the content of the β-turn and β-sheet increased with increasing DDs, which improved the molecular structure and flexibility of wheat gluten. A scanning electron microscope (SEM) revealed that the image of HDG-55% presented the smoothest surface and the least uniform pore, enabling the sample to be more susceptible to enzymatic hydrolysis. The above information will enable us to better understand the effect of structure on the susceptibility of deamidated wheat gluten.

  7. Hydrolysis of chicoric and caftaric acids with esterases and Lactobacillus johnsonii in Vitro and in a gastrointestinal model.

    PubMed

    Bel-Rhlid, Rachid; Pagé-Zoerkler, Nicole; Fumeaux, René; Ho-Dac, Thang; Chuat, Jean-Yves; Sauvageat, Jean Luc; Raab, Thomas

    2012-09-12

    Chicoric acid (ChA) and caftaric acid (CafA) were identified as bioactive components of chicory and have been ascribed a number of health benefits. This study investigated the hydrolysis of ChA and CafA with enzymes and a probiotic bacterium Lactobacillus johnsonii (La1). Esterase from Aspergillus japonicus (24 U/mg) hydrolyzed 100% of ChA (5 mM) and CafA (5 mM) after 3 h, at pH 7.0 and 37 °C. Under the same reaction conditions, 100% hydrolysis of ChA and CafA was achieved with a spray-dried preparation of La1. The addition of La1 (100 mg/mL, 3.3 E9 cfu/g) to CafA solution in a gastrointestinal model (GI model) resulted in 65% hydrolysis of CafA. This model simulates the physicochemical conditions of the human gastrointestinal tract. No hydrolysis of CafA was observed after passage through the GI model in the absence of La1. The results of this study support the hypothesis that ChA and CafA are degraded by gut microflora before absorption and metabolization.

  8. Sequential acid and enzymatic hydrolysis in situ and bioethanol production from Gracilaria biomass.

    PubMed

    Wu, Fang-Chen; Wu, Jane-Yii; Liao, Yi-Jyun; Wang, Man-Ying; Shih, Ing-Lung

    2014-03-01

    Gracilaria sp., a red alga, was used as a feedstock for the production of bioethanol. Saccharification of Gracilaria sp. by sequential acid and enzyme hydrolysis in situ produced a high quality hydrolysate that ensured its fermentability to produce ethanol. The optimal saccharification process resulted in total 11.85g/L (59.26%) of glucose and galactose, Saccharomyces cerevisiae Wu-Y2 showed a good performance on co-fermentability of glucose and galactose released in the hydrolysate from Gracilaria sp. The final ethanol concentrations of 4.72g/L (0.48g/g sugar consumed; 94% conversion efficiency) and the ethanol productivity 4.93g/L/d were achieved. 1g of dry Gracilaria can be converted to 0.236g (23.6%) of bioethanol via the processes developed. Efficient alcohol production by immobilized S. cerevisiae Wu-Y2 in batch and repeated batch fermentation was also demonstrated. The findings of this study revealed that Gracilaria sp. can be a potential feedstock in biorefinery for ethanol production.

  9. Biopolymer from microbial assisted in situ hydrolysis of triglycerides and dimerization of fatty acids.

    PubMed

    Kavitha, V; Radhakrishnan, N; Madhavacharyulu, E; Sailakshmi, G; Sekaran, G; Reddy, B S R; Rajkumar, G Suseela; Gnanamani, Arumugam

    2010-01-01

    The present study demonstrates biopolymer production by in situ bio-based dimerization of fatty acids by microorganism isolated from marine sediments. Microbial isolate grown in Zobell medium in the presence of triglycerides for the period of 24-240 h at 37 degrees C, hydrolyze the applied triglycerides and sequentially dimerized the hydrolyzed products and subsequently polymerized and transformed to a biopolymer having appreciable adhesive properties. Physical (nature, odour, stickyness and tensile strength), chemical (instrumentation) and biochemical (cell free broth) methods of analyses carried out provided the hypotheses involved in the formation of the product as well as the nature of the product formed. Results revealed, lipolytic enzymes released during initial period of growth and the biosurfactant production during later period, respectively, hydrolyze the applied triglycerides and initiate the dimerization and further accelerated when the incubation period extended. The existence and the non-existence of in situ hydrolysis of various triglycerides followed by dimerization and polymerization and the mechanism of transformation of triglycerides to biopolymer are discussed in detail.

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

    PubMed

    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.

  11. A potentiometric study of the hydrolysis of ethylenediaminetetraacetic acid to 150{degrees}C

    SciTech Connect

    Palmer, D.A.; Nguyen-Trung, Chinh

    1995-02-01

    Ethylenediaminetetraacetate anions, EDTA{sup 4-}, were titrated in a hydrogen-electrode concentration cell with an acidic titrant from 0 to 150{degrees}C at 25{degrees}C intervals. These titrations were carried out in the presence of 0. 1, 0.2, and 1.0 mol{center_dot}kg{sup -1} with the supporting electrolytes, sodium chloride, NaCl, and 1.0 mol{center_dot}kg{sup -1} tetramethylammonium trifluoromethylsulfonate, (CH{sub 3}){sub 4}N(F{sub 3}CSO{sub 3}) {l_brace}TMATFMS{r_brace} in order to assess the effect of both cation complexation by EDTA{sup 4-} and anion activity coefficient variations. The resulting hydrolysis quotients are discussed with reference to applications in boiler and heat exchanger chemical cleaning, as well as chemical and nuclear waste containment. Some recent diverse uses of this emf technique that also pertain to these applications will be mentioned briefly, e.g., surface absorption - zero-point-of-charge - measurements to high temperatures and in situ pH measurements in solubility and kinetic experiments.

  12. Fatty acid methyl ester profiles of bat wing surface lipids.

    PubMed

    Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-11-01

    Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration.

  13. Formic acid catalyzed hydrolysis of SO3 in the gas phase: a barrierless mechanism for sulfuric acid production of potential atmospheric importance.

    PubMed

    Hazra, Montu K; Sinha, Amitabha

    2011-11-02

    Computational studies at the B3LYP/6-311++G(3df,3pd) and MP2/6-311++G(3df,3pd) levels are performed to explore the changes in reaction barrier height for the gas phase hydrolysis of SO(3) to form H(2)SO(4) in the presence of a single formic acid (FA) molecule. For comparison, we have also performed calculations for the reference reaction involving water assisted hydrolysis of SO(3) at the same level. Our results show that the FA assisted hydrolysis of SO(3) to form H(2)SO(4) is effectively a barrierless process. The barrier heights for the isomerization of the SO(3)···H(2)O···FA prereactive collision complex, which is the rate limiting step in the FA assisted hydrolysis, are found to be respectively 0.59 and 0.08 kcal/mol at the B3LYP/6-311++G(3df,3pd) and MP2/6-311++G(3df,3pd) levels. This is substantially lower than the ~7 kcal/mol barrier for the corresponding step in the hydrolysis of SO(3) by two water molecules--which is currently the accepted mechanism for atmospheric sulfuric acid production. Simple kinetic analysis of the relative rates suggests that the reduction in barrier height facilitated by FA, combined with the greater stability of the prereactive SO(3)···H(2)O···FA collision complex compared to SO(3)···H(2)O···H(2)O and the rather plentiful atmospheric abundance of FA, makes the formic acid mediated hydrolysis reaction a potentially important pathway for atmospheric sulfuric acid production.

  14. The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

    PubMed

    Olsson, Erik; Menzel, Carolin; Johansson, Caisa; Andersson, Roger; Koch, Kristine; Järnström, Lars

    2013-11-06

    Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred.

  15. Volatile organic acid adsorption and cation dissociation by porphyritic andesite for enhancing hydrolysis and acidogenesis of solid food wastes.

    PubMed

    Cheng, Fan; Li, Ming; Li, Dawei; Chen, Ling; Jiang, Weizhong; Kitamura, Yutaka; Li, Baoming

    2010-07-01

    Volatile organic acid adsorption, cation dissociation by porphyritic andesite, and their effects on the hydrolysis and acidogenesis of solid food wastes were evaluated through batch experiments. The acetic acid adsorption experiments show that pH was mainly regulated by H(+) adsorption. The mono-layer and multi-layer adsorption were found under the low (8.3-83.2 mmol/L) and high (133.22-532.89 mmol/L) initial acetic acid concentration, respectively. The dissociated cations concentration in acidic solution showed the predominance of Ca(2+). Porphyritic andesite addition elevated the pH levels and accelerated hydrolysis and acidogenesis in the batch fermentation experiment. Leachate of porphyritic andesite addition achieved the highest hydrolysis constant of 22.1 x 10(-3)kgm(-2)d(-1) and VS degradation rates of 3.9 g L(-1)d(-1). The highest activity of microorganisms represented by specific growth rate of ATP, 0.16d(-1), and specific consumption rate of Ca(2+), 0.18d(-1), was obtained by adding leachate of porphyritic andesite.

  16. Assessment of the hydrolysis process for the determination of okadaic acid-group toxin ester: presence of okadaic acid 7-O-acyl-ester derivates in Spanish shellfish.

    PubMed

    Villar-González, A; Rodríguez-Velasco, M L; Ben-Gigirey, B; Yasumoto, T; Botana, L M

    2008-04-01

    The contamination of different types of shellfish by okadaic acid (OA)-group toxin esters is an important problem that presents serious risk for human health. During previous investigations carried out in our laboratory by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS), the occurrence of a high percentage of esters in relation to the total OA equivalents has been observed in several shellfish species. The determination of these kinds of toxins using LC/MS or other chemical methods requires a hydrolysis step in order to convert the sterified compounds into the parent toxins, OA, dinophysistoxins-1 (DTX-1) and dinophysistoxins-2 (DTX-2). Most of the hydrolysis procedures are based on an alkaline hydrolysis reaction. However, despite hydrolysis being a critical step within the analysis, it has not been studied in depth up to now. The present paper reports the results obtained after evaluating the hydrolysis process of an esterified form of OA by using a standard of 7-O-acyl ester with palmitoyl as the fatty acid (palOA). Investigations were focused on checking the effectiveness of the hydrolysis for palOA using methanol as solvent standard and matrices matched standards. From the results obtained, no matrix influence on the hydrolysis process was observed and the quantity of palOA converted into OA was always above 80%. The analyses of different Spanish shellfish samples showed percentages of palOA in relation to the total OA esters ranging from 27% to 90%, depending on the shellfish specie.

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

    PubMed Central

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

    2016-01-01

    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

  18. L-lactic acid production from apple pomace by sequential hydrolysis and fermentation.

    PubMed

    Gullón, Beatriz; Yáñez, Remedios; Alonso, José Luis; Parajó, J C

    2008-01-01

    The potential of apple pomace (a solid waste from cider and apple juice making factories) as a source of sugars and other compounds for fermentation was evaluated. The effect of the cellulase-to-solid ratio (CSR) and the liquor-to-solid ratio (LSR) on the kinetics of glucose and total monosaccharide generation was studied. Mathematical models suitable for reproducing and predicting the hydrolyzate composition were developed. When samples of apple pomace were subjected to enzymatic hydrolysis, the glucose and fructose present in the raw material as free monosaccharides were extracted at the beginning of the process. Using low cellulase and cellobiase charges (8.5 FPU/g-solid and 8.5 IU/g-solid, respectively), 79% of total glucan was saccharified after 12 h, leading to solutions containing up to 43.8 g monosaccharides/L (glucose, 22.8 g/L; fructose, 14.8 g/L; xylose+mannose+galactose, 2.5 g/L; arabinose+rhamnose, 2.8g/L). These results correspond to a monosaccharide/cellulase ratio of 0.06 g/FPU and to a volumetric productivity of 3.65 g of monosaccharides/L h. Liquors obtained under these conditions were used for fermentative lactic acid production with Lactobacillus rhamnosus CECT-288, leading to media containing up to 32.5 g/L of L-lactic acid after 6 h (volumetric productivity=5.41 g/L h, product yield=0.88 g/g).

  19. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  20. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  1. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  2. 40 CFR 721.10365 - Butanoic acid, 3-mercapto-2-methyl-, ethyl ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-, ethyl ester. 721.10365 Section 721.10365 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10365 Butanoic acid, 3-mercapto-2-methyl-, ethyl ester. (a) Chemical... acid, 3-mercapto-2-methyl-, ethyl ester (PMN P-10-56; CAS No. 888021-82-7) is subject to...

  3. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  4. 40 CFR 721.10365 - Butanoic acid, 3-mercapto-2-methyl-, ethyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-, ethyl ester. 721.10365 Section 721.10365 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10365 Butanoic acid, 3-mercapto-2-methyl-, ethyl ester. (a) Chemical... acid, 3-mercapto-2-methyl-, ethyl ester (PMN P-10-56; CAS No. 888021-82-7) is subject to...

  5. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  6. 40 CFR 721.10365 - Butanoic acid, 3-mercapto-2-methyl-, ethyl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-, ethyl ester. 721.10365 Section 721.10365 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.10365 Butanoic acid, 3-mercapto-2-methyl-, ethyl ester. (a) Chemical... acid, 3-mercapto-2-methyl-, ethyl ester (PMN P-10-56; CAS No. 888021-82-7) is subject to...

  7. 40 CFR 721.2075 - Carbamodithioic acid, methyl-, compound with methanamine (1:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-, compound with methanamine (1:1). 721.2075 Section 721.2075 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.2075 Carbamodithioic acid, methyl-, compound with... substance identified generically as carbamodithioic acid, methyl-, compound with methanamine (1:1)...

  8. 40 CFR 721.2075 - Carbamodithioic acid, methyl-, compound with methanamine (1:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-, compound with methanamine (1:1). 721.2075 Section 721.2075 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.2075 Carbamodithioic acid, methyl-, compound with... substance identified generically as carbamodithioic acid, methyl-, compound with methanamine (1:1)...

  9. 40 CFR 721.2075 - Carbamodithioic acid, methyl-, compound with methanamine (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-, compound with methanamine (1:1). 721.2075 Section 721.2075 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.2075 Carbamodithioic acid, methyl-, compound with... substance identified generically as carbamodithioic acid, methyl-, compound with methanamine (1:1)...

  10. 40 CFR 721.2075 - Carbamodithioic acid, methyl-, compound with methanamine (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-, compound with methanamine (1:1). 721.2075 Section 721.2075 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.2075 Carbamodithioic acid, methyl-, compound with... substance identified generically as carbamodithioic acid, methyl-, compound with methanamine (1:1)...

  11. 40 CFR 721.2075 - Carbamodithioic acid, methyl-, compound with methanamine (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-, compound with methanamine (1:1). 721.2075 Section 721.2075 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.2075 Carbamodithioic acid, methyl-, compound with... substance identified generically as carbamodithioic acid, methyl-, compound with methanamine (1:1)...

  12. Revisiting the mechanism of neutral hydrolysis of esters: water autoionization mechanisms with acid or base initiation pathways.

    PubMed

    da Silva, Poliana Lima; Guimarães, Luciana; Pliego, Josefredo R

    2013-05-30

    The mechanism of neutral hydrolysis of ester has long been explored by theoretical studies. However, reliable theoretical calculations show that the usual bifunctional catalysis mechanism reported by different authors cannot explain the experimental kinetics. An important advance was recently reported by Gunaydin and Houk, suggesting that ions are involved in the mechanism and the process initiates by water autoionization followed by protonation of the ester (W(AI)A mechanism). However, this mechanism does not explain the hydrolysis of activated esters. In this work, we have used ab initio calculations, continuum solvation models, and intrinsic reaction coordinate method to support the W(AI)A mechanism for normal ester. In the case of activated esters, the process can also be viewed as water autoionization with formation of hydroxide ion aided by a second water molecule acting as a general base (W(AI)B mechanism). This is the mechanism that was proposed by Jencks and Carriuolo 50 years ago. Our analysis point out that the usual method for exploring mechanisms, searching for saddle points, may not work for problems like the present one, since there are no saddle points on the reaction pathway. Rather, the formation of a pair of ions from a neutral species may have an asymptotic barrier. The approach used in this paper allows the calculation of the free energy profile and enable us to explain the mechanism and kinetics of the neutral hydrolysis of normal (methyl acetate) and activated (methyl trifluoroacetate) esters. In addition, the present study suggests that formation of a pair of ions should always be considered in reactions in aqueous solution.

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

    PubMed

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

    2015-06-25

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

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

    PubMed

    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.

  15. 21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters... following prescribed conditions: (a) The additive consists of a mixture of either methyl or ethyl esters...

  16. 21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters... following prescribed conditions: (a) The additive consists of a mixture of either methyl or ethyl esters...

  17. 21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters... following prescribed conditions: (a) The additive consists of a mixture of either methyl or ethyl esters...

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

    SciTech Connect

    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.

  19. Sulfuric acid hydrolysis and detoxification of red alga Pterocladiella capillacea for bioethanol fermentation with thermotolerant yeast Kluyveromyces marxianus.

    PubMed

    Wu, Chien-Hui; Chien, Wei-Chen; Chou, Han-Kai; Yang, Jungwoo; Lin, Hong-Ting Victor

    2014-09-01

    One-step sulfuric acid saccharification of the red alga Pterocladiella capillacea was optimized, and various detoxification methods (neutralization, overliming, and electrodialysis) of the acid hydrolysate were evaluated for fermentation with the thermotolerant yeast Kluyveromyces marxianus. A proximate composition analysis indicated that P. capillacea was rich in carbohydrates. A significant galactose recovery of 81.1 ± 5% was also achieved under the conditions of a 12% (w/v) biomass load, 5% (v/v) sulfuric acid, 121°C, and hydrolysis for 30 min. Among the various detoxification methods, electrodialysis was identified as the most suitable for fermentable sugar recovery and organic acid removal (100% reduction of formic and levulinic acids), even though it failed to reduce the amount of the inhibitor 5-HMF. As a result, K. marxianus fermentation with the electrodialyzed acid hydrolysate of P. capillacea resulted in the best ethanol levels and fermentation efficiency.

  20. Lewis acid assisted methyl/chlorine exchange in silylated hydrazinochlorophosphanes.

    PubMed

    Westenkirchner, Andrea; Villinger, Alexander; Karaghiosoff, Konstantin; Wustrack, Ronald; Michalik, Dirk; Schulz, Axel

    2011-03-21

    Differently substituted hydrazinophosphanes of the type (Me(3)Si)(2)N-N(SiMe(3))-PR(1)R(2) (R(1) = Cl with R(2) = Me, C(6)F(5) and R(1) = Me, R(2) = C(6)H(5)) have been studied in the reaction with Lewis acids such as ECl(3) (E = Al, Ga). For (Me(3)Si)(2)N-N(SiMe(3))-P(Cl)(Me) and (Me(3)Si)(2)N-N(SiMe(3))-P(Me)(C(6)H(5)), only adduct formation was found while a chlorine/methyl exchange reaction was observed for (Me(3)Si)(2)N-N(SiMe(3))-P(Cl)R (R = C(6)H(5) and C(6)F(5)) leading to the formation of (Me(2)ClSi)(Me(3)Si)N-N(SiMe(3))-P(Me)R, which crystallize as ECl(3) adducts. The free hydrazinophosphanes can be obtained by removal of the Lewis acid with the help of a strong base such as 4-(dimethylamino)pyridine (DMAP).

  1. Determination of DNA adducts by combining acid-catalyzed hydrolysis and chromatographic analysis of the carcinogen-modified nucleobases.

    PubMed

    Leung, Elvis M K; Deng, Kailin; Wong, Tin-Yan; Chan, Wan

    2016-01-01

    The commonly used method of analyzing carcinogen-induced DNA adducts involves the hydrolysis of carcinogen-modified DNA samples by using a mixture of enzymes, followed by (32)P-postlabeling or liquid chromatography (LC)-based analyses of carcinogen-modified mononucleotides/nucleosides. In the present study, we report the development and application of a new approach to DNA adduct analysis by combining the H(+)/heat-catalyzed release of carcinogen-modified nucleobases and the use of LC-based methods to analyze DNA adducts. Results showed that heating the carcinogen-modified DNA samples at 70 °C for an extended period of 4 to 6 h in the presence of 0.05% HCl can efficiently induce DNA depurination, releasing the intact carcinogen-modified nucleobases for LC analyses. After optimizing the hydrolysis conditions, DNA samples with C8- and N (2) -modified 2'-deoxyguanosine, as well as N (6) -modified 2'-deoxyadenosine, were synthesized by reacting DNA with 1-nitropyrene, acetaldehyde, and aristolochic acids, respectively. These samples were then hydrolyzed, and the released nucleobase adducts were analyzed using LC-based analytical methods. Analysis results demonstrated a dose-dependent release of target DNA adducts from carcinogen-modified DNA samples, indicating that the developed H(+)/heat-catalyzed hydrolysis method was quantitative. Comparative studies with enzymatic digestion method on carcinogen-modified DNA samples revealed that the two hydrolysis methods did not yield systematically different results.

  2. Biocatalytic Resolution of Rac-α-Ethyl-2-Oxo-Pyrrolidineacetic Acid Methyl Ester by Immobilized Recombinant Bacillus cereus Esterase.

    PubMed

    Zheng, Jian-Yong; Liu, Yin-Yan; Luo, Wei-Feng; Zheng, Ren-Chao; Ying, Xiang-Xian; Wang, Zhao

    2016-04-01

    A new esterase-producing strain (Bacillus cereus WZZ001) which exhibiting high hydrolytic activity and excellent enantioselectivity on rac-α-ethyl-2-oxo-pyrrolidineacetic acid methyl ester (R, S-1) has been isolated from soil sample by our laboratory. In this study, the stereoselective hydrolysis of (R, S-1) was performed using the recombinant Bacillus cereus esterase which expressed in Escherichia coli BL21 (DE3). Under the optimized conditions of pH 8.0, 35 °C, and concentration of substrate 400 mM, a successful enzymatic resolution was achieved with an e.e. s of 99.5 % and conversion of 49 %. Immobilization considerably increased the reusability of the recombinant esterase; the immobilized enzyme showed excellent reusability during 6 cycles of repeated 2 h reactions at 35 °C. Thereby, it makes the recombinant B. cereus esterase a usable biocatalyst for industrial application.

  3. ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular structure. The energy diffe...

  4. Hormone-sensitive lipase activity and triacylglycerol hydrolysis are decreased in rat soleus muscle by cyclopiazonic acid.

    PubMed

    Watt, Matthew J; Steinberg, Gregory R; Heigenhauser, G J F; Spriet, Lawrence L; Dyck, David J

    2003-08-01

    Cyclopiazonic acid (CPA) is a sarcoplasmic reticulum Ca2+-ATPase inhibitor that increases intracellular calcium. The role of CPA in regulating the oxidation and esterification of palmitate, the hydrolysis of intramuscular lipids, and the activation of hormone-sensitive lipase (HSL) was examined in isolated rat soleus muscles at rest. CPA (40 micro M) was added to the incubation medium to levels that resulted in subcontraction increases in muscle tension, and lipid metabolism was monitored using the previously described pulse-chase procedure. CPA did not alter the cellular energy state, as reflected by similar muscle contents of ATP, phosphocreatine, free AMP, and free ADP. CPA increased total palmitate uptake into soleus muscle (11%, P < 0.05) and was without effect on palmitate oxidation. This resulted in greater esterification of exogenous palmitate into the triacylglycerol (18%, P < 0.05) and phospholipid (89%, P < 0.05) pools. CPA decreased (P < 0.05) intramuscular lipid hydrolysis, and this occurred as a result of reduced HSL activity (20%, P < 0.05). Incubation of muscles with 3 mM caffeine, which is also known to increase Ca2+ without affecting the cellular energy state, reduced HSL activity (24%, P < 0.05). KN-93, a calcium/calmodulin-dependent kinase inhibitor (CaMKII), blocked the effects of CPA and caffeine, and HSL activity returned to preincubation values. The results of the present study demonstrate that CPA simultaneously decreases intramuscular triacylglycerol (IMTG) hydrolysis and promotes lipid storage in isolated, intact soleus muscle. The decreased IMTG hydrolysis is likely mediated by reduced HSL activity, possibly via the CaMKII pathway. These responses are not consistent with the increased hydrolysis and decreased esterification observed in contracting muscle when substrate availability and the hormonal milieu are tightly controlled. It is possible that more powerful signals or a higher [Ca2+] may override the lipid-storage effect of the CPA

  5. Hydrolysis mechanism of anticancer drug lobaplatin in aqueous medium under neutral and acidic conditions: A DFT study

    NASA Astrophysics Data System (ADS)

    Reddy B., Venkata P.; Mukherjee, Subhajit; Mitra, Ishani; Mahata, Sujay; Linert, Wolfgang; Moi, Sankar Ch.

    2016-10-01

    We have studied the hydrolysis mechanism of lobaplatin in aqueous medium under neutral and acidic conditions using density functional theory combining with CPCM model. The stationary states located on potential energy surface were fully optimized and characterised. The rate limiting step in neutral conditions, ring opening reaction with an activation energy of 110.21 kJ mol-1. The completely hydrolysed complex is expected to be the reactive species towards the DNA purine bases. In acidic conditions, ligand detachment is the rate limiting step with an activation energy of 113.82 kJ mol-1. Consequently, monohydrated complex is expected to be the species reacting with DNA.

  6. Neuroprotection in rabbit retina with N-acetyl-aspartylglutamate and 2-phosphonyl-methyl pentanedioic acid

    NASA Astrophysics Data System (ADS)

    Hacker, Henry D.; Yourick, Debra L.; Koenig, Michael K.; Slusher, Barbara S.; Meyerhoff, James L.

    1999-06-01

    Retinal tissue is subject to ischemia from diabetic retinopathy and other conditions that affect the retinal vasculature such as lupus erythematosus and temporal arteritis. There is evidence in animal models of reversible ischemia that a therapeutic window exists during early recovery when agents that reduce glutamate activity at its receptor sites can rescue neurons from injury. To model ischemia, we used sodium cyanide (NaCN), to inhibit oxidative metabolism, and 2-deoxyglucose (2-DG) to inhibit glycolysis. Dissociated rabbit retina cells were studied to evaluate the potential neuroprotective effects of N-acetyl-aspartyl-glutamate (MAAG), which competes with glutamate as a low-potency agonist at the NMDA receptor complex. N-acetylated α-linked acidic dipeptidase (NAALADase; the NAAG-hydrolyzing enzyme) is responsible for the hydrolysis of NAAG into glutamate, a neurotransmitter and potent excitotoxin, and N-acetylaspartate. 2-Phosphonyl-methyl pentanedioic acid (PMPA) and β-linked NAAG (β-NAAG), inhibitors of NAALADase, were also tested, since inhibition of NAALADase could reduce synaptic glutamate and increase the concentration of NAAG. We found that metabolic inhibition with NaCN/2-DG for 1 hour caused 50% toxicity as assessed with the MTT assay. Co-treatment with NAAG resulted in dose-dependent protection of up to 55% (p<0.005). When the non-hydrolyzable, NAALADase inhibitor β-NAAG was employed dose-dependent protection of up to 37% was observed (p<0.001). PMPA also showed 48% protection (p<.05-.001) against these insults. These data suggest that NAAG may antagonize the effect of glutamate at the NMDA receptor complex in retina. Inhibition of NAALADase by PMPA and β-NAAG may increase the activity of endogenous NAAG.

  7. Functional analysis of a tomato salicylic acid methyl transferase and its role in synthesis of the flavor volatile methyl salicylate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl salicylate (MeSA) is a volatile plant secondary metabolite that is an important contributor to taste and scent of many fruits and flowers. It is synthesized from salicylic acid (SA), a phytohormone that contributes to plant pathogen defense. MeSA is synthesized by members of a family of O-met...

  8. Acid Catalysis in Basic Solution: A Supramolecular Host PromotesOrthoformate Hydrolysis

    SciTech Connect

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

    2007-12-12

    Though many enzymes can promote chemical reactions by tuning substrate properties purely through the electrostatic environment of a docking cavity, this strategy has proven challenging to mimic in synthetic host-guest systems. Here we report a highly-charged, water soluble, metal-ligand assembly with a hydrophobic interior cavity that thermodynamically stabilizes protonated substrates and consequently catalyzes the normally acidic hydrolysis of orthoformates in basic solution, with rate accelerations of up to 890-fold. The catalysis reaction obeys Michaelis-Menten kinetics, exhibits competitive inhibition, and the substrate scope displays size selectivity consistent with the constrained binding environment of the molecular host. Synthetic chemists have long endeavored to design host molecules capable of selectively binding slow-reacting substrates and catalyzing their chemical reactions. While synthetic catalysts are often site-specific and require certain properties of the substrate to insure catalysis, enzymes are often able to modify basic properties of the bound substrate such as pK{sub a} in order to enhance reactivity. Two common motifs used by nature to activate otherwise unreactive compounds are the precise arrangement of hydrogen-bonding networks and electrostatic interactions between the substrate and adjacent residues of the protein. Precise arrangement of hydrogen bonding networks near the active sites of proteins can lead to well-tuned pK{sub a}-matching, and can result in pK{sub a} shifts of up to eight units, as shown in bacteriorhodopsin. Similarly, purely electrostatic interactions can greatly favor charged states and have been responsible for pK{sub a} shifts of up to five units for acetoacetate decarboxylase. Attempts have been made to isolate the contributions of electrostatic versus covalent interactions to such pK{sub a} shifts; however this remains a difficult challenge experimentally. This challenge emphasizes the importance of synthesizing

  9. Studies of the acidic components of the Colorado Green River formation oil shale-Mass spectrometric identification of the methyl esters of extractable acids.

    NASA Technical Reports Server (NTRS)

    Haug, P.; Schnoes, H. K.; Burlingame, A. L.

    1971-01-01

    Study of solvent extractable acidic constituents of oil shale from the Colorado Green River Formation. Identification of individual components is based on gas chromatographic and mass spectrometric data obtained for their respective methyl esters. Normal acids, isoprenoidal acids, alpha, omega-dicarboxylic acids, mono-alpha-methyl dicarboxylic acids and methyl ketoacids were identified. In addition, the presence of monocyclic, benzoic, phenylalkanoic and naphthyl-carboxylic acids, as well as cycloaromatic acids, is demonstrated by partial identification.

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

    NASA Astrophysics Data System (ADS)

    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)

  11. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    ABSTRACT

    Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

  12. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  13. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  14. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  15. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  16. 40 CFR 180.318 - 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for residues.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...)butanoic acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, in or on the following food... acid; tolerance for residues. 180.318 Section 180.318 Protection of Environment ENVIRONMENTAL... FOOD Specific Tolerances § 180.318 4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerance for...

  17. Methyl esters from vegetable oils with hydroxy fatty acids: Comparison of lesquerella and castor methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The search for alternative feedstocks for biodiesel as partial replacement for petrodiesel has recently extended to castor oil. In this work, the castor oil methyl esters were prepared and their properties determined in comparison to the methyl esters of lesquerella oil, which in turn is seen as alt...

  18. Hyper-thermal acid hydrolysis and adsorption treatment of red seaweed, Gelidium amansii for butyric acid production with pH control.

    PubMed

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

    2017-03-01

    Optimal hyper-thermal (HT) acid hydrolysis conditions for Gelidium amansii were determined to be 12% (w/v) seaweed slurry content and 144 mM H2SO4 at 150 °C for 10 min. HT acid hydrolysis-treated G. amansii hydrolysates produced low concentrations of inhibitory compounds and adsorption treatment using 3% activated carbon. An adsorption time of 5 min was subsequently used to remove the inhibitory 5-hydroxymethylfurfural from the medium. A final maximum monosaccharide concentration of 44.6 g/L and 79.1% conversion from 56.4 g/L total fermentable monosaccharides with 120 g dw/L G. amansii slurry was obtained from HT acid hydrolysis, enzymatic saccharification, and adsorption treatment. This study demonstrates the potential for butyric acid production from G. amansii hydrolysates under non-pH-controlled as well as pH-controlled fermentation using Clostridium acetobutylicum KCTC 1790. The activated carbon treatment and pH-controlled fermentation showed synergistic effects and produced butyric acid at a concentration of 11.2 g/L after 9 days of fermentation.

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

    PubMed Central

    2011-01-01

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

  20. Methylation of deoxyribonucleic acid in cultured mammalian cells by N-methyl-N′-nitro-N-nitrosoguanidine. The influence of cellular thiol concentrations on the extent of methylation and the 6-oxygen atom of guanine as a site of methylation

    PubMed Central

    Lawley, P. D.; Thatcher, Carolyn J.

    1970-01-01

    1. In neutral aqueous solution N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) yields salts of nitrocyanamide as u.v.-absorbing products. With cysteine, as found independently by Schulz & McCalla (1969), the principal product is 2-nitràminothiazoline-4-carboxylic acid. Both these reactions liberate the methylating species; thiols enhance the rate markedly at neutral pH values. An alternative reaction with thiols gives cystine, presumably via the unstable S-nitrosocysteine. 2. Thiols (glutathione or N-acetylcysteine) in vitro at about the concentration found in mammalian cells enhance the rate of methylation of DNA markedly over that in neutral solution. 3. Treatment of cultured mammalian cells with MNNG results in rapid methylation of nucleic acids, the extent being greater the higher the thiol content of the cells. Rodent embryo cells are more extensively methylated than mouse L-cells of the same thiol content. Cellular thiol concentrations are decreased by MNNG. Proteins are less methylated by MNNG than are nucleic acids. 4. Methylation of cells by dimethyl sulphate does not depend on cellular thiol content and protein is not less methylated than nucleic acids. Methylation by MNNG may therefore be thiol-stimulated in cells. 5. Both in vitro and in cells about 7% of the methylation of DNA by MNNG occurs at the 6-oxygen atom of guanine. The major products 7-methylguanine and 3-methyladenine are given by both MNNG and dimethyl sulphate, but dimethyl sulphate does not yield O6-methylguanine. Possible reaction mechanisms to account for this difference between these methylating agents and its possible significance as a determinant of their biological effects are discussed. PMID:5435496

  1. A relationship between vitamin B sub 12 , folic acid, ascorbic acid, and mercury uptake and methylation

    SciTech Connect

    Zorn, N.E.; Smith, J.T. )

    1990-01-01

    Ingestion of megadoses of certain vitamins appears to influence the in vivo methylation of mercuric chloride in guinea pigs. The addition of megadoses of vitamin B{sub 12} fed either singularly or in combination with folic acid resulted in increased methylmercury concentrations in the liver. Moreover, percent methylmercury levels were significantly increased with B{sub 12} treatment in the liver (B{sub 12} only and B{sub 12}/folic acid) and brain (B{sub 12}/vitamin C). Incorporation of high levels of folic acid into the dietary regime also increased the methylmercury concentration particularly in the liver and hair tissues. The addition of vitamin C in the diet, particularly in combination with B{sub 12} (brain) or folic acid (muscle) resulted in increased methylmercury levels in these tissues and percent methylmercury values with B{sub 12} in the muscle and brain tissue.

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

    NASA Astrophysics Data System (ADS)

    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.

  3. 75 FR 50926 - 2-propenoic acid, 2-methyl-, C12-16-alkyl esters, telomers with 1-dodecanethiol, polyethylene...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... AGENCY 40 CFR Part 180 2-propenoic acid, 2-methyl-, C12-16-alkyl esters, telomers with 1-dodecanethiol... tolerance for residues of 2-propenoic acid, 2-methyl-, C12-16- alkyl esters, telomers with 1-dodecanethiol... residues of 2-propenoic acid, 2-methyl-, C12-16-alkyl esters, telomers with 1-dodecanethiol,...

  4. Hydrolysis of substance P in the presence of the osteosarcoma cell line SaOS-2: release of free amino acids.

    PubMed

    Cavazza, Antonella; Marini, Mario; Roda, L Giorgio; Tarantino, Umberto; Valenti, Angela

    2011-12-01

    The possible hydrolysis of substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met) in presence of the osteoblastic cell line SaOS-2 was measured by capillary electrophoresis coupled to mass detection. The results obtained indicate that a very rapid disappearance of the intact undecapeptide was associated to a slower appearance of seven of its eight component amino acids. These results can be interpreted as indicating that an extremely fast hydrolysis of substance P by endopeptidases, which released peptidic by-products, was followed by a noticeably slower secondary degradation which released free amino acids. In decreasing quantitative importance, these phenomena appear to originate by the hydrolysis of the Pro(4)-Gln(5) bond, followed by C-terminal sequential degradation of the Arg(1)-Pro(4) tetrapeptide; by the hydrolysis of or Phe(7)-Phe(8) bond (or, possibly, of Gln(6)-Phe(7)) leading to release of free Phe and Gln; by hydrolysis of the Gly(9)-Leu(10) bond with subsequent release of Met and Leu. Results obtained appear to be compatible with the expression by SaOS-2 cells of enzymes already known to catalyze substance P hydrolysis, together with an apparent low efficiency of aminopeptidases. Because of the activity of C-terminal fragments on NK1 receptors, the delay between primary hydrolysis of substance P and secondary hydrolysis of its peptidic fragments indicated by the data shown implies a possible persistence of substance P physiological effects even after degradation of the intact peptide.

  5. Corrosion resistance of siloxane-poly(methyl methacrylate) hybrid films modified with acetic acid on tin plate substrates: Influence of tetraethoxysilane addition

    NASA Astrophysics Data System (ADS)

    Kunst, S. R.; Cardoso, H. R. P.; Oliveira, C. T.; Santana, J. A.; Sarmento, V. H. V.; Muller, I. L.; Malfatti, C. F.

    2014-04-01

    The aim of this paper is to study the corrosion resistance of hybrid films. Tin plate was coated with a siloxane-poly (methyl methacrylate) (PMMA) hybrid film prepared by sol-gel route with covalent bonds between the organic (PMMA) and inorganic (siloxane) phases obtained by hydrolysis and polycondensation of 3-(trimethoxysilylpropyl) methacrylate (TMSM) and polymerization of methyl methacrylate (MMA) using benzoyl peroxide (BPO) as a thermic initiator. Hydrolysis reactions were catalyzed by acetic acid solution avoiding the use of chlorine or stronger acids in the film preparation. The effect of the addition of tetraethoxysilane (TEOS) on the protective properties of the film was evaluated. The hydrophobicity of the film was determined by contact angle measurements, and the morphology was evaluated by scanning electron microscopy (SEM) and profilometry. The local nanostructure was investigated by Fourier transform infrared spectroscopy (FT-IR). The electrochemical behavior of the films was assessed by open circuit potential monitoring, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements in a 0.05 M NaCl solution. The mechanical behavior was evaluated by tribology. The results highlighted that the siloxane-PMMA hybrid films modified with acetic acid are promising anti-corrosive coatings that acts as an efficient diffusion barrier, protecting tin plates against corrosion. However, the coating properties were affected by the TEOS addition, which contributed for the thickness increase and irregular surface coverage.

  6. [Neuroepigenetics: Desoxyribonucleic acid methylation in Alzheimer's disease and other dementias].

    PubMed

    Mendioroz Iriarte, Maite; Pulido Fontes, Laura; Méndez-López, Iván

    2015-05-21

    DNA methylation is an epigenetic mechanism that controls gene expression. In Alzheimer's disease (AD), global DNA hypomethylation of neurons has been described in the human cerebral cortex. Moreover, several variants in the methylation pattern of candidate genes have been identified in brain tissue when comparing AD patients and controls. Specifically, DNA methylation changes have been observed in PSEN1 and APOE, both genes previously being involved in the pathophysiology of AD. In other degenerative dementias, methylation variants have also been described in key genes, such as hypomethylation of the SNCA gene in Parkinson's disease and dementia with Lewy bodies or hypermethylation of the GRN gene promoter in frontotemporal dementia. The finding of aberrant DNA methylation patterns shared by brain tissue and peripheral blood opens the door to use those variants as epigenetic biomarkers in the diagnosis of neurodegenerative diseases.

  7. Kinetic and Modeling Investigation to Provide Design Guidelines for the NREL Dilute-Acid Process Aimed at Total Hydrolysis/Fractionation of Lignocellulosic Biomass: July 1998

    SciTech Connect

    Lee, Y. Y.; Iyer, P.; Xiang, Q.; Hayes, J.

    2004-08-01

    Following up on previous work, subcontractor investigated three aspects of using NREL ''pretreatment'' technology for total hydrolysis (cellulose as well as hemicellulose) of biomass. Whereas historic hydrolysis of biomass used either dilute acid or concentrated acid technology for hydrolysis of both hemicellulose and cellulose, NREL has been pursuing very dilute acid hydrolysis of hemicellulose followed by enzymatic hydrolysis of cellulose. NREL's countercurrent shrinking-bed reactor design for hemicellulose hydrolysis (pretreatment) has, however, shown promise for total hydrolysis. For the first task, subcontractor developed a mathematical model of the countercurrent shrinking bed reactor operation and, using yellow poplar sawdust as a feedstock, analyzed the effect of: initial solid feeding rate, temperature, acid concentration, acid flow rate, Peclet number (a measure of backmixing in liquid flow), and bed shrinking. For the second task, subcontractor used laboratory trials, with yellow poplar sawdust and 0.07 wt% sulfuric acid at various temperatures, to verify the hydrolysis of cellulose to glucose (desired) and decomposition of glucose (undesired) and determine appropriate parameters for use in kinetic models. Unlike cellulose and hemicellulose, lignins, the third major component of biomass, are not carbohydrates that can be broken down into component sugars. They are, however, aromatic complex amorphous phenolic polymers that can likely be converted into low-molecular weight compounds suitable for production of fuels and chemicals. Oxidative degradation is one pathway for such conversion and hydrogen peroxide would be an attractive reagent for this, as it would leave no residuals. For the third task, subcontractor reacted lignin with hydrogen peroxide under various conditions and analyzed the resulting product mix.

  8. Effective methylation of phosphonic acids related to chemical warfare agents mediated by trimethyloxonium tetrafluoroborate for their qualitative detection and identification by gas chromatography-mass spectrometry.

    PubMed

    Valdez, Carlos A; Leif, Roald N; Alcaraz, Armando

    2016-08-24

    The effective methylation of phosphonic acids related to chemical warfare agents (CWAs) employing trimethyloxonium tetrafluoroborate (TMO·BF4) for their qualitative detection and identification by gas chromatography-mass spectrometry (GC-MS) is presented. The methylation occurs in rapid fashion (1 h) and can be conveniently carried out at ambient temperature, thus providing a safer alternative to the universally employed diazomethane-based methylation protocols. Optimization of the methylation parameters led us to conclude that methylene chloride was the ideal solvent to carry out the derivatization, and that even though methylated products can be observed surfacing after only 1 h, additional time was not found to be detrimental but beneficial to the process particularly when dealing with analytes at low concentrations (∼10 μg mL(-1)). Due to its insolubility in methylene chloride, TMO·BF4 conveniently settles to the bottom during the reaction and does not produce additional interfering by-products that may further complicate the GC-MS analysis. The method was demonstrated to successfully methylate a variety of Schedule 2 phosphonic acids, including their half esters, resulting in derivatives that were readily detected and identified using the instrument's spectral library. Most importantly, the method was shown to simultaneously methylate a mixture of the organophosphorus-based nerve agent hydrolysis products: pinacolyl methylphosphonate (PMPA), cyclohexyl methylphosphonate (CyMPA) and ethyl methylphosphonate (EMPA) (at a 10 μg mL(-1) concentration each) in a fatty acid ester-rich organic matrix (OPCW-PT-O3) featured in the 38th Organisation for the Prohibition of Chemical Weapons (OPCW) Proficiency Test. In addition, the protocol was found to effectively methylate N,N-diethylamino ethanesulfonic acid and N,N-diisopropylamino ethanesulfonic acid that are products arising from the oxidative degradation of the V-series agents VR and VX respectively. The

  9. Total synthesis of (±)-epithuriferic acid methyl ester via Diels-Alder reaction.

    PubMed

    Koprowski, Marek; Bałczewski, Piotr; Owsianik, Krzysztof; Różycka-Sokołowska, Ewa; Marciniak, Bernard

    2016-02-07

    In this paper, we have described the first total synthesis of (±)-epithuriferic acid methyl ester from non-natural sources, in four steps (20% overall yield). The key step involves the Diels-Alder reaction of isobenzofuran with methyl 3-(dimethoxyphosphoryl)acrylate which is controlled by "ortho" regio- and endo stereoselectivities due to the COOMe group.

  10. Chemically modified fatty acid methyl esters: their potential for use as lubrication fluids and surfactants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A review of recent developments in the synthesis and characterization of lubrication fluids and surfactants from methyl oleate. The synthesis of materials made using an epoxidation route is the focus. This versatile method of chemical modification of fatty acid methyl esters improves their oxidati...

  11. An efficient preparation of N-methyl-alpha-amino acids from N-nosyl-alpha-amino acid phenacyl esters.

    PubMed

    Leggio, Antonella; Belsito, Emilia Lucia; De Marco, Rosaria; Liguori, Angelo; Perri, Francesca; Viscomi, Maria Caterina

    2010-03-05

    In this paper we describe a simple and efficient solution-phase synthesis of N-methyl-N-nosyl-alpha-amino acids and N-Fmoc-N-methyl-alpha-amino acids. This represents a very important application in peptide synthesis to obtain N-methylated peptides in both solution and solid phase. The developed methodology involves the use of N-nosyl-alpha-amino acids with the carboxyl function protected as a phenacyl ester and the methylating reagent diazomethane. An important aspect of this synthetic strategy is the possibility to selectively deprotect the carboxyl function or alternatively both amino and carboxyl moieties by using the same reagent with a different molar excess and under mild conditions. Furthermore, the adopted procedure keeps unchanged the acid-sensitive side chain protecting groups used in Fmoc-based synthetic strategies.

  12. A new sunscreen of the cinnamate class: synthesis and enzymatic hydrolysis evaluation of glyceryl esters of p-methoxycinnamic acid.

    PubMed

    de Freitas, Zaida Maria Faria; dos Santos, Elisabete Pereira; da Rocha, João Ferreira; Dellamora-Ortiz, Gisela Maria; Gonçalves, José Carlos Saraiva

    2005-05-01

    Glyceryl esters of p-methoxycinnamic acid, 1,3-dipalmitoyl-2-p-methoxycinnamoyl-1,2,3-propanetriol and 1,3-dioctanoyl-2-p-methoxycinnamoyl-1,2,3-propanetriol were synthesised in an attempt to increase substantivity and decrease eventual undesirable effects of sunscreens of this class. To assess if the glyceryl esters could present a higher stability towards hydrolysis by lipases in the stratum corneum, hydrolysis rates were determined in vitro using a commercial fungal lipase from Rhizomucor miehei. Results presented herein show that the glyceryl esters have similar lambda(max) and epsilon values to sunscreens of the cinnamate class. The ester 1,3-dipalmitoyl-2-p-methoxycinnamoyl-1,2,3-propanetriol presented a 2.8 times lower hydrolysis rate by lipase, in vitro, than the commercial sunscreen 2-ethylhexyl-p-methoxycinnamate (alkyl ester). This finding suggests that this triacylglycerol can possibly have a longer retention time in the skin and consequently promote a more intense and effective antisolar action than the commercial sunscreen.

  13. Increased blood plasma hydrolysis of acetylsalicylic acid in type 2 diabetic patients: a role of plasma esterases.

    PubMed

    Gresner, Peter; Dolník, Martin; Waczulíková, Iveta; Bryszewska, Maria; Sikurová, Libusa; Watala, Cezary

    2006-02-01

    Hydrolysis of acetylsalicylic acid (ASA, aspirin), an antiplatelet drug commonly used in the prevention of stroke and myocardial infarction, seems to play a crucial role in its pharmacological action. Thirty-eight healthy volunteers and 38 type 2 diabetic patients were enrolled to test the hypothesis that the enhanced plasma degradation and lowered bioavailability of ASA in diabetic patients is associated with the attenuation of platelet response. Aspirin esterase activities were tested at pH 7.4 and 5.5. A significantly higher overall aspirin esterase activity was noted at pH 7.4 in the diabetic patients (P<0.003), corresponding to faster ASA hydrolysis (P<0.006). This increased activity was attributable to butyrylcholinesterase and probably to albumin, because it was effectively inhibited by eserine and 4-bis-nitrophenyl phosphate (P<0.01). No significant differences between control and diabetic subjects were found at pH 5.5 in either enzymatic activities or ASA hydrolysis rates. The enhanced plasma ASA degradation in diabetic subjects was significantly associated with the refractoriness of blood platelets to ASA (P<0.05) and modulated by plasma cholesterol (P<0.01). No direct effects of plasma pH or albumin were observed. In conclusion, higher aspirin esterase activity contributes to the lowered response of diabetic platelets to ASA-mediated antiplatelet therapy.

  14. Spectroscopic and quantum chemical analysis of Isonicotinic acid methyl ester

    NASA Astrophysics Data System (ADS)

    Shoba, D.; Periandy, S.; Govindarajan, M.; Gayathri, P.

    2015-02-01

    In this present study, an organic compound Isonicotinic acid methyl ester (INAME) was structurally characterized by FTIR, FT-Raman, and NMR and UV spectroscopy. The optimized geometrical parameters and energies of all different and possible conformers of INAME are obtained from Density Functional Theory (DFT) by B3LYP/6-311++G(d,p) method. There are three conformers (SI, SII-1, and SII-2) for this molecule (ground state). The most stable conformer of INAME is SI conformer. The molecular geometry and vibrational frequencies of INAME in the ground state have been calculated by using HF and density functional method (B3LYP) 6-311++G (d,p) basis set. Detailed vibrational spectral analysis has been carried out and assignments of the observed fundamental bands have been proposed on the basis of peak positions and relative intensities. The computed vibrational frequencies were compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. A study on the electronic properties, such as HOMO and LUMO energies were performed by time independent DFT approach. Besides, molecular electrostatic potential (MEP) and thermodynamic properties were performed. The electric dipole moment (μ) and first hyper polarizability (β) values of the investigated molecule were computed using ab initio quantum mechanical calculations. The calculated results show that the INAME molecule may have microscopic nonlinear optical (NLO) behavior with non zero values. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by gauge independent atomic orbital (GIAO) method.

  15. 8-Methoxypsoralen-nucleic acid photoreaction. Effect of methyl substitution on pyrone vs. furan photoaddition

    SciTech Connect

    Kanne, D.; Rapoport, H.; Hearst, J.E.

    1984-04-01

    We have synthesized a series of 8-(3H)methoxypsoralens in which methyl and hydrogen are systematically varied at the 4- and 5'-positions. Analysis of the products resulting from the photoaddition of these four psoralens with the nucleic acid poly(dA-dT) reveals that the product distribution depends on the presence or absence of a 4-methyl substituent. Compounds with the 4-methyl group show an overwhelming preference (approximately 98%) for addition to the furan double bond, while compounds without the 4-methyl show a substantial amount (approximately 18%) of addition to the pyrone double bond.

  16. AVOIDING PITFALLS IN THE DETERMINATION OF HALOCARBOXYLIC ACIDS: THE PHOTOCHEMISTRY OF METHYLATION

    EPA Science Inventory

    Haloethanoic (haloacetic) acids are formed during chlorination of drinking water and are regulated by the Environmental Protection Agency (EPA). These compounds are normally quantified by gas chromatography with electron capture detection (GC-ECD) ad the methyl esters. EPA Meth...

  17. Design and biological properties of iodine-123 labeled. beta. -methyl-branched fatty acids

    SciTech Connect

    Knapp, F.F. Jr.; Goodman, M.M.

    1984-01-01

    The synthetic strategy, synthesis, preclinical evaluation and potential clinical applications of 3-methyl-branched radioiodinated iodophenyl- and iodovinyl-substituted fatty acids are reviewed for use as myocardial imaging agents. 50 references, 6 figures. (ACR)

  18. Validation of thermally assisted hydrolysis and methylation-gas chromatography for rapid and direct compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) in whole bacterial cells.

    PubMed

    Baidurah, Siti; Murugan, Paramasivam; Joyyi, Lee; Fukuda, Junya; Yamada, Masaya; Sudesh, Kumar; Ishida, Yasuyuki

    2016-11-04

    Thermally assisted hydrolysis and methylation-gas chromatography (THM-GC) in the presence of an organic alkali was validated for the compositional analysis of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] accumulated in whole bacterial cells. Recombinant Cupriavidus necator Re2058/pCB113 was grown in a batch fermentation with different concentration of palm oil and fructose in order to control the molar fraction of 3HHx in P(3HB-co-3HHx) produced in the cells. Trace amounts (30μg) of freeze-dried cells were directly subjected to THM-GC in the presence of tetramethylammonium hydroxide (TMAH) at 400°C. The obtained chromatograms clearly showed nine characteristic peaks, attributed to the THM products from 3HB and 3HHx units in the polymer chains, without any appreciable interference by the bacterial matrix components. Based on these peak intensities, the copolymer compositions were determined rapidly without using any cumbersome and lengthy sample pretreatment as in conventional GC method. Moreover, the compositions thus obtained were strongly correlated with those by NMR and conventional GC involving solvent extraction.

  19. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid,...

  20. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid,...

  1. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid,...

  2. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid,...

  3. 40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid,...

  4. Preparation of fatty acid methyl esters from Osage orange (Maclura pomifera) oil and evaluation as biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid methyl esters were prepared in high yield by transesterification of Osage orange (Maclura pomifera) oil. Extracted using supercritical CO2, the crude oil was initially treated with mineral acid and methanol to lower its content of free fatty acids, thus rendering it amenable to homogeneou...

  5. 75 FR 78243 - Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-15

    ... AGENCY Propionic Acid and Salts, Urea Sulfate, Methidathion, and Methyl Parathion; Registration Review... pesticides propionic acid and salts, case no. 4078, urea sulfate, case no. 7213, methidathion, case no. 0034... pesticides in the table below--propionic acid and salts, case 4078, urea sulfate, case no. 7213,...

  6. [Study on the acid hydrolysis, fiber remodeling and bionics mineralization of rat tail tendon collagen type Ⅰ].

    PubMed

    Zhang, Zhan; Zhang, Chun; Guo, Qiaofeng

    2016-05-25

    Objective: To produce bionic bone material that is consistent with human bone in chemical composition and molecular structure using rat tail tendon collagen type Ⅰ. Methods: The type Ⅰcollagen derived from rat tail was extracted by acetic acid to form collagen fibers. The reconstructed collagen fibers were placed in the mineralized solution to mimic bone mineralization for 2-6 days. Bone mineralization was observed by transmission electron microscopy and electron diffraction.Results: Collagen fibers with characteristic D-Band structure were reconstructed by using rat tail tendon collagen type Ⅰ extracted with acid hydrolysis method. Transmission electron microscopy and electron diffraction showed that calcium hydroxyapatite precursor infiltrated into the collagen fibers, and the collagen fibers were partially mineralized after 2 days of mineralization; the collagen fibers were completely mineralized and bionic bone material of typeⅠ collagen/calcium hydroxyapatite was formed after 6 days of mineralization.Conclusion: The collagen type Ⅰ can be extracted from rat tail tendon by acid hydrolysis method, and can be reformed and mineralized to form the bionic bone material which mimics human bone in chemical composition and the molecular structure.

  7. Impact of pretreatment with dilute sulfuric acid under moderate temperature on hydrolysis of corn stover with two enzyme systems.

    PubMed

    Tai, Chao; Keshwani, Deepak

    2014-03-01

    Pretreatment of corn stover with dilute sulfuric acid at moderate temperature was investigated, and glucan digestibility by Cellic CTec2 and Celluclast on the pretreated biomass was compared. Pretreatments were carried out from 60 to 180 min at the temperature from 105 to 135 °C, with acid concentrations ranging from 0.5 to 2% (w/v). Significant portion of xylan was removed during pretreatment, and the glucan digestibility by CTec2 was significantly better than that by Celluclast in all cases. Analysis showed that glucan digestibility by both two enzymes correlated directly with the extent of xylan removal in pretreatment. Confidence interval was built to give a more precise range of glucan conversion and to test the significant difference among pretreatment conditions. Response surface model was built to obtain the optimal pretreatment condition to achieve high glucan conversion after enzymatic hydrolysis. Considering the cost and energy savings, the optimal pretreatment condition of 1.75% acid for 160 min at 135 °C was determined, and glucan conversion can achieve the range from 72.86 to 76.69% at 95% confidence level after enzymatic hydrolysis, making total glucan recovery up to the range from 89.42 to 93.25%.

  8. Effect of catalyst concentration and reaction time on the extraction of glucomannan from porang (Amorphophallus oncophyllus) flour via acid hydrolysis

    NASA Astrophysics Data System (ADS)

    Kumoro, A. C.; Yuganta, T. H. A.; Ratnawati, R.; Retnowati, D. S.

    2016-11-01

    High demand of glucomannan for various applications has attracted the attention of researchers to look for efficient extraction method from its botanical sources. The aim of this study is to investigate the effect of catalyst concentration and reaction time on the yield and purity of glucomannan, and profile of reducing sugar during glucomannan extraction from crude porang flour via acid hydrolysis. The effect of catalyst concentration was found to be more pronounced over the effect of reaction time. When catalyst concentration was varied from 0.03125 to 1 M, extraction of glucomannan from porang flour for 1 hour at 60°C yielded 40.5 to 70% glucomannan with purity of 47.35 to 90.18% (w/w). The yield and purity of glucomannan obtained from extraction using catalyst concentration of 1 M for 0.25 to 3 hour ranged between 49 to 66.67% and 58.32 to 90.18% (w/w), respectively. Reduction in glucomannan yield and purity observed at high catalyst concentration and prolong reaction time was likely to be due to over-decomposition. Glucomannan with highest purity (90.18% w/w) was obtained at 66.67% yield from acid hydrolysis of porang flour using 0.5 M hydrochloric acid solution with flour:water ratio of 1:50 at 60°C for 1 hour.

  9. 75 FR 770 - Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2-methyl-2-[(1-oxo-2-propenyl)amino...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... AGENCY 40 CFR Part 180 Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2- methyl-2... residues of acrylic acid-benzyl methacrylate-1- propanesulfonic acid, 2-methyl-2- -, monosodium salt... to establish a maximum permissible level for residues of acrylic acid-benzyl...

  10. 40 CFR 721.1645 - Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono[(C10-16-alkyloxy)methyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-, reaction products with oxirane mono derivatives and 2,2,4(or 2,4,4)-trimethyl-1,6-hexanediamine. 721.1645... Substances § 721.1645 Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono derivatives and 2... to reporting. (1) The chemical substance benzenesulfonic acid, 4-methyl-, reaction products...

  11. 40 CFR 721.1645 - Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono[(C10-16-alkyloxy)methyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-, reaction products with oxirane mono derivatives and 2,2,4(or 2,4,4)-trimethyl-1,6-hexanediamine. 721.1645... Substances § 721.1645 Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono derivatives and 2... to reporting. (1) The chemical substance benzenesulfonic acid, 4-methyl-, reaction products...

  12. 40 CFR 721.1645 - Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono[(C10-16-alkyloxy)methyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-, reaction products with oxirane mono derivatives and 2,2,4(or 2,4,4)-trimethyl-1,6-hexanediamine. 721.1645... Substances § 721.1645 Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono derivatives and 2... to reporting. (1) The chemical substance benzenesulfonic acid, 4-methyl-, reaction products...

  13. 40 CFR 721.1645 - Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono[(C10-16-alkyloxy)methyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-, reaction products with oxirane mono derivatives and 2,2,4(or 2,4,4)-trimethyl-1,6-hexanediamine. 721.1645... Substances § 721.1645 Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono derivatives and 2... to reporting. (1) The chemical substance benzenesulfonic acid, 4-methyl-, reaction products...

  14. 40 CFR 721.1645 - Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono[(C10-16-alkyloxy)methyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-, reaction products with oxirane mono derivatives and 2,2,4(or 2,4,4)-trimethyl-1,6-hexanediamine. 721.1645... Substances § 721.1645 Benzenesulfonic acid, 4-methyl-, reaction products with oxirane mono derivatives and 2... to reporting. (1) The chemical substance benzenesulfonic acid, 4-methyl-, reaction products...

  15. The hydrolysis of polyimides

    NASA Technical Reports Server (NTRS)

    Hoagland, P. D.; Fox, S. W.

    1973-01-01

    Thermal polymerization of aspartic acid produces a polysuccinimide (I), a chain of aspartoyl residues. An investigation was made of the alkaline hydrolysis of the imide rings of (I) which converts the polyimide to a polypeptide. The alkaline hydrolysis of polyimides can be expected to be kinetically complex due to increasing negative charge generated by carboxylate groups. For this reason, a diimide, phthaloyl-DL-aspartoyl-beta-alanine (IIA) was synthesized for a progressive study of the hydrolysis of polyimides. In addition, this diimide (IIA) can be related to thalidomide and might be expected to exhibit similar reactivity during hydrolysis of the phthalimide ring.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Associations between whole peripheral blood fatty acids and DNA methylation in humans

    PubMed Central

    de la Rocha, Carmen; Pérez-Mojica, J. Eduardo; León, Silvia Zenteno-De; Cervantes-Paz, Braulio; Tristán-Flores, Fabiola E.; Rodríguez-Ríos, Dalia; Molina-Torres, Jorge; Ramírez-Chávez, Enrique; Alvarado-Caudillo, Yolanda; Carmona, F. Javier; Esteller, Manel; Hernández-Rivas, Rosaura; Wrobel, Katarzyna; Wrobel, Kazimierz; Zaina, Silvio; Lund, Gertrud

    2016-01-01

    Fatty acids (FA) modify DNA methylation in vitro, but limited information is available on whether corresponding associations exist in vivo and reflect any short-term effect of the diet. Associations between global DNA methylation and FAs were sought in blood from lactating infants (LI; n = 49) and adult males (AMM; n = 12) equally distributed across the three conventional BMI classes. AMM provided multiple samples at 2-hour intervals during 8 hours after either a single Western diet-representative meal (post-prandial samples) or no meal (fasting samples). Lipid/glucose profile, HDAC4 promoter and PDK4 5’UTR methylation were determined in AMM. Multiple regression analysis revealed that global (in LI) and both global and PDK4-specific DNA methylation (in AMM) were positively associated with eicosapentaenoic and arachidonic acid. HDAC4 methylation was inversely associated with arachidonic acid post-prandially in AMM. Global DNA methylation did not show any defined within-day pattern that would suggest a short-term response to the diet. Nonetheless, global DNA methylation was higher in normal weight subjects both post-prandially and in fasting and coincided with higher polyunsaturated relative to monounsaturated and saturated FAs. We show for the first time strong associations of DNA methylation with specific FAs in two human cohorts of distinct age, diet and postnatal development stage. PMID:27181711

  18. Simultaneous determination of acetylsalicylic acid and salicylic acid in human plasma by isocratic high-pressure liquid chromatography with post-column hydrolysis and fluorescence detection.

    PubMed

    Hobl, Eva-Luise; Jilma, Bernd; Ebner, Josef; Schmid, Rainer W

    2013-06-01

    A selective, sensitive and rapid high-performance liquid chromatography method with post-column hydrolysis and fluorescence detection was developed for the simultaneous quantification of acetylsalicylic acid and its metabolite salicylic acid in human plasma. Following the addition of 2-hydroxy-3-methoxybenzoic acid as internal standard and simple protein precipitation with acetonitrile, the analytes were separated on a ProntoSIL 120 C18 ace-EPS column (150 × 2 mm, 3 µm) protected by a C8 guard column (5 µm). The mobile phase, 10 mm formic acid in water (pH 2.9) and acetonitrile (70:30, v/v), was used at a flow rate of 0.35 mL/min. After on-line post-column hydrolysis of acetylsalicylic acid (ASA) to salicylic acid (SA) by addition of alkaline solution, the analytes were measured at 290 nm (λex ) and 400 nm (λem ). The method was linear in the concentration ranges between 0.05 and 20 ng/μL for both ASA and SA with a lower limit of quantification of 25 pg/μL for SA and 50 pg/μL for ASA. The limit of detection was 15 pg/μL for SA and 32.5 pg/μL for ASA. The analysis of ASA and SA can be carried out within 8 min; therefore this method is suitable for measuring plasma concentrations of salicylates in clinical routine.

  19. 40 CFR 721.4097 - 7-Oxabicyclo[4.1.0]heptane-3-carboxylic acid, methyl ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., methyl ester. 721.4097 Section 721.4097 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4097 7-Oxabicyclo heptane-3-carboxylic acid, methyl ester. (a) Chemical...-oxabicyclo heptane-3-carboxylic acid, methyl ester (PMN P-98-101) is subject to reporting under this...

  20. 40 CFR 721.4097 - 7-Oxabicyclo[4.1.0]heptane-3-carboxylic acid, methyl ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., methyl ester. 721.4097 Section 721.4097 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4097 7-Oxabicyclo heptane-3-carboxylic acid, methyl ester. (a) Chemical...-oxabicyclo heptane-3-carboxylic acid, methyl ester (PMN P-98-101) is subject to reporting under this...

  1. 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.

    PubMed

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

    2016-08-08

    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

  2. The fatty-acid amide hydrolase inhibitor URB597 does not affect triacylglycerol hydrolysis in rat tissues.

    PubMed

    Clapper, Jason R; Duranti, Andrea; Tontini, Andrea; Mor, Marco; Tarzia, Giorgio; Piomelli, Daniele

    2006-11-01

    The O-arylcarbamate URB597 (cyclohexylcarbamic acid 3'-carbamoylbiphenyl-3-yl ester; also referred to as KDS-4103) is a potent inhibitor of fatty-acid amide hydrolase (FAAH), an intracellular serine hydrolase responsible for the inactivation of the endogenous cannabinoid anandamide. URB597 demonstrates a remarkable degree of selectivity for FAAH over other serine hydrolases (e.g. cholinesterases) or other components of the endocannabinoid system (e.g. cannabinoid receptors). However, in a proteomic-based selectivity screen based on the displacement of fluorophosphonate-rhodamine (FPR) from mouse brain proteins, it was recently shown that URB597 prevents FPR binding to triacylglycerol hydrolase (TGH) with a median inhibitory concentration of 192nM. To determine whether this effect correlates with inhibition of TGH activity, we investigated the ability of URB597 to inhibit triolein hydrolysis in rat liver and heart tissues, which are rich in TGH, as well as white adipose tissue (WAT), which is rich in adipose triacylglycerol lipase (TGL) and hormone-sensitive lipase. The results show that URB597 does not affect triolein hydrolysis in any of these tissues at concentrations as high as 10microM, whereas it inhibits FAAH activity at low nanomolar concentrations. Moreover, intraperitoneal (i.p.) administration of URB597 at doses that maximally inhibit FAAH in vivo (0.3-3mgkg(-1)) exerts no effect on triolein hydrolysis and tissue triacylglycerol (TAG) levels in rat liver, heart or WAT. The results indicate that URB597, while potent at inhibiting FAAH, does not affect TGH and TGL activities in rat tissues.

  3. Lipoxygenase in Caragana jubata responds to low temperature, abscisic acid, methyl jasmonate and salicylic acid.

    PubMed

    Bhardwaj, Pardeep Kumar; Kaur, Jagdeep; Sobti, Ranbir Chander; Ahuja, Paramvir Singh; Kumar, Sanjay

    2011-09-01

    Lipoxygenase (LOX) catalyses oxygenation of free polyunsaturated fatty acids into oxylipins, and is a critical enzyme of the jasmonate signaling pathway. LOX has been shown to be associated with biotic and abiotic stress responses in diverse plant species, though limited data is available with respect to low temperature and the associated cues. Using rapid amplification of cDNA ends, a full-length cDNA (CjLOX) encoding lipoxygenase was cloned from apical buds of Caragana jubata, a temperate plant species that grows under extreme cold. The cDNA obtained was 2952bp long consisting of an open reading frame of 2610bp encoding 869 amino acids protein. Multiple alignment of the deduced amino acid sequence with those of other plants demonstrated putative LH2/ PLAT domain, lipoxygenase iron binding catalytic domain and lipoxygenase_2 signature sequences. CjLOX exhibited up- and down-regulation of gene expression pattern in response to low temperature (LT), abscisic acid (ABA), methyl jasmonate (MJ) and salicylic acid (SA). Among all the treatments, a strong up-regulation was observed in response to MJ. Data suggests an important role of jasmonate signaling pathway in response to LT in C. jubata.

  4. How to identify and discriminate between the methyl quinates of chlorogenic acids by liquid chromatography-tandem mass spectrometry.

    PubMed

    Jaiswal, Rakesh; Kuhnert, Nikolai

    2011-03-01

    The methyl esters of chlorogenic acids, methyl quinates, are widely distributed in plant materials and frequently appear as extraction artifacts in plant samples. This is the first time when liquid chromatography-tandem mass spectrometry methods have been used for the identification and characterization of the methyl quinates. For this purpose, methyl quinates of mono caffeoylquinic acids and mono feruloylquinic acids were synthesized as authentic standards. The methyl quinates of mono and diacyl chlorogenic acids have shown characteristic fragmentation pattern in their tandem mass spectra. MS(n + 1) spectra of the methyl quinates of diacyl chlorogenic acids were identical to MS(n) spectra of mono acyl derivatives. These quinates do not produce any methyl quinate peak at m/z 205 if compared with quinic acid peak at m/z 191 in negative ion mode. In the MS(n) spectra of these quinates, cinnamic acid part or cinnamoyl part was detected as a base peak in negative ion mode. The retention time, order of elution and fragmentation pattern were completely different if compared with LC-MS(n) methods developed for chlorogenic acids. These LC-MS(n) methods have been applied for the identification and regioisomeric characterization of the methyl quinates of chlorogenic acids in maté tea and woodruff (Galium odoratum). Two methyl caffeoylquinates (2 and 4) were identified as methyl 3-caffeoylquinate and methyl 5-caffeoylquinate.

  5. Proton affinity of methyl nitrate - Less than proton affinity of nitric acid

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.; Rice, Julia E.

    1992-01-01

    Several state-of-the-art ab initio quantum mechanical methods were used to investigate the equilibrium structure, dipole moments, harmonic vibrational frequencies, and IR intensities of methyl nitrate, methanol, and several structures of protonated methyl nitrate, using the same theoretical methods as in an earlier study (Lee and Rice, 1992) of nitric acid. The ab initio results for methyl nitrate and methanol were found to be in good agreement with available experimental data. The proton affinity (PA) of methyl nitrate was calculated to be 176.9 +/-5 kcal/mol, in excellent agreement with the experimental value 176 kcal/mol obtained by Attina et al. (1987) and less than the PA value of nitric acid. An explanation of the discrepancy of the present results with those of an earlier study on protonated nitric acid is proposed.

  6. Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang

    2012-01-01

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.

  7. Interaction between amylose and 1-butanol during 1-butanol-hydrochloric acid hydrolysis of normal rice starch.

    PubMed

    Hu, Xiuting; Wei, Benxi; Zhang, Bao; Li, Hongyan; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2013-10-01

    The aim of this study was to examine the interaction between amylose and 1-butanol during the 1-butanol-hydrochloric acid (1-butanol-HCl) hydrolysis of normal rice starch. The interaction model between amylose and 1-butanol was proposed using gas chromatography-mass spectrometry (GC-MS), (13)C cross polarization and magic angle spinning NMR analysis ((13)C CP/MAS NMR), differential scanning calorimetry (DSC), and thermalgravimetric analysis (TGA). GC-MS data showed that another form of 1-butanol existed in 1-butanol-HCl-hydrolyzed normal rice starch, except in the form of free molecules absorbed on the starch granules. The signal of 1-butanol-HCl-hydrolyzed starch at 100.1 ppm appeared in the (13)C CP/MAS NMR spectrum, indicating that the amylose-1-butanol complex was formed. DSC and TGA data also demonstrated the formation of the complex, which significantly affected the thermal properties of normal rice starch. These findings revealed that less dextrin with low molecular weight formed might be attributed to resistance of this complex to acid during 1-butanol-HCl hydrolysis.

  8. Three-step biocatalytic reaction using whole cells for efficient production of tyramine from keratin acid hydrolysis wastewater.

    PubMed

    Zhang, Hongjuan; Wei, Yu; Lu, Yang; Wu, Siping; Liu, Qian; Liu, Junzhong; Jiao, Qingcai

    2016-02-01

    Tyramine has been paid more attention in recent years as a significant metabolite of tyrosine and catecholamine drug and an intermediate of medicinal material and some drugs. In this study, an effective, green, and three-step biocatalytic synthesis method for production of tyramine starting from serine in keratin acid hydrolysis wastewater was developed and investigated. Serine deaminase from Escherichia coli was first combined with tyrosine phenol-lyase from Citrobacter koseri, to convert L-serine to L-tyrosine. L-Tyrosine can then be decarboxylated to tyramine by tyrosinede carboxylase from Lactobacillus brevis. All these enzymes originated from recombinant whole cells. Serine deaminaseand tyrosine phenol-lyase could efficiently convert L-serine in wastewater to L-tyrosine at pH 8.0, 37 °C, and Triton X-100 of 0.04% when tyrosine phenol-lyase and its corresponding substrates were sequentially added. Tyrosine conversion rate reached 98 % by L-tyrosine decarboxylase. In scale-up study, the conversion yield of L-serine in wastewater to tyrosine was up to 89 %. L-Tyrosine was decarboxylated to tyramine with a high yield 94 %. Tyramine hydrochloride was obtained with a total yield 84 %. This study has provided an efficient way of recycling keratin acid hydrolysis wastewater to produce tyramine.

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

    PubMed

    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.

  10. Biosorption of methyl blue onto tartaric acid modified wheat bran from aqueous solution.

    PubMed

    Yao, Shuhua; Lai, Hong; Shi, Zhongliang

    2012-12-05

    Tartaric acid modified wheat bran was utilized as adsorbent to remove methyl blue, a basic dye from aqueous solution. Batch experiments were carried out to study the effect of various experimental parameters such as initial solution pH, contact time, initial dye concentration and adsorbent dosage, on dye adsorption. The results showed that the modification of wheat bran by tartaric acid significantly improved its adsorption capacity, and made this material a suitable adsorbent to remove methyl blue. The adsorption capacity of modified wheat bran was about 1.6 times higher than that of unmodified one. The amount of methyl blue adsorbed was found to vary with initial solution pH, adsorbent dosage, contact time and initial methyl blue concentration. Kinetics study showed that the overall adsorption rate of methyl blue was illustrated by pseudo-second-order kinetic model. The applicability of the Langmuir and Freundlich models for the data was tested. Both models adequately described the experimental data of the biosorption of methyl blue. The maximum adsorption capacity for methyl blue calculated from Langmuir model was 25.18 mg/g. The study has shown the effectiveness of modified wheat bran in the removal of methyl blue, and that it can be considered as an attractive alternative to the more expensive technologies used in wastewater treatment.

  11. Biosorption of methyl blue onto tartaric acid modified wheat bran from aqueous solution

    PubMed Central

    2012-01-01

    Tartaric acid modified wheat bran was utilized as adsorbent to remove methyl blue, a basic dye from aqueous solution. Batch experiments were carried out to study the effect of various experimental parameters such as initial solution pH, contact time, initial dye concentration and adsorbent dosage, on dye adsorption. The results showed that the modification of wheat bran by tartaric acid significantly improved its adsorption capacity, and made this material a suitable adsorbent to remove methyl blue. The adsorption capacity of modified wheat bran was about 1.6 times higher than that of unmodified one. The amount of methyl blue adsorbed was found to vary with initial solution pH, adsorbent dosage, contact time and initial methyl blue concentration. Kinetics study showed that the overall adsorption rate of methyl blue was illustrated by pseudo-second-order kinetic model. The applicability of the Langmuir and Freundlich models for the data was tested. Both models adequately described the experimental data of the biosorption of methyl blue. The maximum adsorption capacity for methyl blue calculated from Langmuir model was 25.18 mg/g. The study has shown the effectiveness of modified wheat bran in the removal of methyl blue, and that it can be considered as an attractive alternative to the more expensive technologies used in wastewater treatment. PMID:23369295

  12. Modeling the production of sugar and byproducts from acid bisulfite pretreatment and enzymatic hydrolysis of Douglas-fir.

    PubMed

    Liu, Yalan; Wang, Jinwu; Wolcott, Michael

    2017-01-01

    The aim of this work was to investigate the kinetics of multiple chemicals in acid bisulfite pretreatment and the relationship between total sugar yields and pretreatment factors (temperature and time). The results showed Saeman model accurately fitted the pretreatment process. According to this kinetic model, a maximum hemicellulose hydrolysis yield was achieved at a treatment time of 75min with a temperature of 145°C. Meantime, the concentrations of acetic acid, hydroxymethylfurfural (HMF), and furfural were 1.54, 0.60, and 1.15gL(-1), respectively. Also, a Lorentzian function described the relationship between total sugar yield and pretreatment factors: temperature and time. The regression parameters from this mathematical fitting have accurately reflected the maximum total sugar yield and the optimal treatment conditions were determined to be 145°C and 110min.

  13. Characterization of N-methylated amino acids by GC-MS after ethyl chloroformate derivatization.

    PubMed

    Reddy, B Sudarshana; Chary, V Naresh; Pavankumar, P; Prabhakar, S

    2016-08-01

    Methylation is an essential metabolic process in the biological systems, and it is significant for several biological reactions in living organisms. Methylated compounds are known to be involved in most of the bodily functions, and some of them serve as biomarkers. Theoretically, all α-amino acids can be methylated, and it is possible to encounter them in most animal/plant samples. But the analytical data, especially the mass spectral data, are available only for a few of the methylated amino acids. Thus, it is essential to generate mass spectral data and to develop mass spectrometry methods for the identification of all possible methylated amino acids for future metabolomic studies. In this study, all N-methyl and N,N-dimethyl amino acids were synthesized by the methylation of α-amino acids and characterized by a GC-MS method. The methylated amino acids were derivatized with ethyl chloroformate and analyzed by GC-MS under EI and methane/CI conditions. The EI mass spectra of ethyl chloroformate derivatives of N-methyl (1-18) and N,N-dimethyl amino acids (19-35) showed abundant [M-COOC2 H5 ](+) ions. The fragment ions due to loss of C2 H4 , CO2 , (CO2  + C2 H4 ) from [M-COOC2 H5 ](+) were of structure indicative for 1-18. The EI spectra of 19-35 showed less number of fragment ions when compared with those of 1-18. The side chain group (R) caused specific fragment ions characteristic to its structure. The methane/CI spectra of the studied compounds showed [M + H](+) ions to substantiate their molecular weights. The detected EI fragment ions were characteristic of the structure that made easy identification of the studied compounds, including isomeric/isobaric compounds. Fragmentation patterns of the studied compounds (1-35) were confirmed by high-resolution mass spectra data and further substantiated by the data obtained from (13) C2 -labeled glycines and N-ethoxycarbonyl methoxy esters. The method was applied to human plasma samples for the identification

  14. Quantification of primary fatty acid amides in commercial tallow and tallow fatty acid methyl esters by HPLC-APCI-MS.

    PubMed

    Madl, Tobias; Mittelbach, Martin

    2005-04-01

    Primary fatty acid amides are a group of biologically highly active compounds which were already identified in nature. Here, these substances were determined in tallow and tallow fatty acid methyl esters for the first time. As tallow is growing in importance as an oleochemical feedstock for the soap manufacturing, the surfactant as well as the biodiesel industry, the amounts of primary fatty acid amides have to be considered. As these compounds are insoluble in tallow as well as in the corresponding product e.g. tallow fatty acid methyl esters, filter plugging can occur. For the quantification in these matrices a purification step and a LC-APCI-MS method were developed. Although quantification of these compounds can be performed by GC-MS, the presented approach omitted any derivatization and increased the sensitivity by two orders of magnitude. Internal standard calibration using heptadecanoic acid amide and validation of the method yielded a limit of detection of 18.5 fmol and recoveries for the tallow and fatty acid methyl ester matrices of 93% and 95%, respectively. A group of commercially available samples were investigated for their content of fatty acid amides resulting in an amount of up to 0.54%m/m (g per 100 g) in tallow and up to 0.16%m/m (g per 100 g) in fatty acid methyl esters.

  15. Methyl-branched poly(hydroxyalkanoate) biosynthesis from 13- methyltetradecanoic acid and mixed isostearic acid isomer substrates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas resinovorans, a known medium-chain-length (mcl-) poly(hydroxyalkanoate) (PHA) producer, was grown on 13-methyltetradecanoic acid (13-MTDA) and a mixture of isostearic acid (IA) isomers to produce methyl-branched mcl-PHA polymers. Shake flask experiments revealed polymer productivities (...

  16. Actinomycin synthesis in Streptomyces antibioticus: enzymatic conversion of 3-Hydroxyanthranilic acid to 4-methyl-3-hydroxyanthranilic acid

    SciTech Connect

    Jones, G.H.

    1987-12-01

    A methyltransferase with utilizes 3-hydroxyanthranilic acid (HAA) as a substrate was identified in detergent-treated extracts of the bacterium Streptomyces antibioticus. The enzyme catalyzes the transfer of methyl groups from (/sup 14/C)S-adenosylmethionine to HAA, but does not catalyze the methylation of 3-hydroxy-DL-kynurenine. Enzyme, substrate, time, and pH dependencies for the methyl transfer reaction were examined. Reaction products obtained from scaled-up reaction mixtures were fractionated by chromatography on Dowex 1, and the Dowex 1 fractions were examined by paper and thin-layer chromatography. One Dowex fraction was shown to contain a radioactive product with the chromatographic properties of 4-methyl-3-hydroxyanthranilic acid (MHA), a known intermediate in the biosynthesis of actinomycin. Available evidence indicates that the conversion of HAA to MHA is an early step in the biosynthesis of actinomycin by S. antibioticus and other actinomycin-producing streptomycetes.

  17. VvMJE1 of the grapevine (Vitis vinifera) VvMES methylesterase family encodes for methyl jasmonate esterase and has a role in stress response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The known members of the plant methyl esterase (MES) family catalyze hydrolysis of a C-O ester linkage of methyl esters of several phytohormones including indole-3-acetic acid, salicylic acid, and jasmonic acid. The genome of grapevine (Vitis vinifera) was found to contain 15 MES genes, designated V...

  18. A rapid hydrolysis method and DABS-Cl derivatization for complete amino acid analysis of octreotide acetate by reversed phase HPLC.

    PubMed

    Akhlaghi, Yousef; Ghaffari, Solmaz; Attar, Hossein; Alamir Hoor, Amir

    2015-11-01

    Octreotide as a synthetic cyclic octapeptide is a somatostatin analog with longer half-life and more selectivity for inhibition of the growth hormone. The acetate salt of octreotide is currently used for medical treatment of somatostatin-related disorders such as endocrine and carcinoid tumors, acromegaly, and gigantism. Octreotide contains both cysteine and tryptophan residues which make the hydrolysis part of its amino acid analysis procedure very challenging. The current paper introduces a fast and additive-free method which preserves tryptophan and cysteine residues during the hydrolysis. Using only 6 M HCl, this hydrolysis process is completed in 30 min at 150 °C. This fast hydrolysis method followed by pre-column derivatization of the released amino acids with 4-N,N-dimethylaminoazobenzene-4'-sulfonyl chloride (DABS-Cl) which takes only 20 min, makes it possible to do the complete amino acid analysis of an octreotide sample in a few hours. The highly stable-colored DABS-Cl derivatives can be detected in 436 nm in a reversed phase chromatographic system, which eliminates spectral interferences to a great extent. The amino acid analysis of octreotide acetate including hydrolysis, derivatization, and reversed phase HPLC determination was validated according to International Conference of Harmonization (ICH) guidelines.

  19. Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: investigation of sucrose-citric acid mixtures.

    PubMed

    Kwok, Kaho; Mauer, Lisa J; Taylor, Lynne S

    2010-11-24

    Previous studies have shown that deliquescent organic compounds frequently exhibit chemical instability when stored in environmental conditions above their deliquescence relative humidity (RH). The goal of the current study was to investigate the effect of atmospheric moisture on the long-term chemical stability of crystalline sucrose-citric acid mixtures following storage at RHs at and below the mutual deliquescence relative humidity (MDRH). Interestingly, it was found that sucrose hydrolysis can occur below the MDRH of 64% and was observed for samples stored at 54% RH. However, hydrolysis was not seen for samples stored at 33 or 43% RH. The rate of sucrose hydrolysis could be modeled by taking into account the rate and extent of moisture uptake, which in turn was dependent on the composition of the powder and the storage RH. A reaction mechanism initiated by capillary condensation and involving additional deliquescence lowering by the degradation products formed as a result of sucrose hydrolysis (glucose and fructose) was proposed.

  20. Wet disk milling pretreatment without sulfuric acid for enzymatic hydrolysis of rice straw.

    PubMed

    Hideno, Akihiro; Inoue, Hiroyuki; Tsukahara, Kenichiro; Fujimoto, Shinji; Minowa, Tomoaki; Inoue, Seiichi; Endo, Takashi; Sawayama, Shigeki

    2009-05-01

    Rice straw has recently attracted interest in Japan as a potential source of raw material for ethanol production. Wet disk milling, a continuous pretreatment to enhance the enzymatic digestibility of rice straw, was compared with conventional ball milling and hot-compressed water treatment. Pretreated rice straw was evaluated by enzymatic hydrolysis using Acremonium cellulase and characterized by X-ray diffraction and scanning electron microscopy. Glucose and xylose yields by wet disk milling, ball milling, and hot-compressed water treatment were 78.5% and 41.5%, 89.4% and 54.3%, and 70.3% and 88.6%, respectively. Wet disk milling and hot-compressed water treatment increased sugar yields without decreasing their crystallinity. The feature size of the wet disk milled rice straw was similar to that of hot-compressed water-treated rice straw. The energy consumption of wet disk milling was lower than that of other pretreatments. Thus, wet disk milling is an economical, practical pretreatment for the enzymatic hydrolysis of lignocellulosic biomass, especially herbaceous biomass such as rice straw.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Systematic cyanobacterial membrane proteome analysis by combining acid hydrolysis and digestive enzymes with nano-liquid chromatography-Fourier transform mass spectrometry.

    PubMed

    Kwon, Joseph; Oh, Jeehyun; Park, Chiyoul; Cho, Kun; Kim, Seung Il; Kim, Soohyun; Lee, Sunghoon; Bhak, Jong; Norling, Birgitta; Choi, Jong-Soon

    2010-01-15

    The identification of membrane proteins is currently under-represented since the trans-membrane domains of membrane proteins have a hydrophobic property. Membrane proteins have mainly been analyzed by cleaving and identifying exposed hydrophilic domains. We developed the membrane proteomics method for targeting integral membrane proteins by the following sequential process: in-solution acid hydrolysis, reverse phase chromatographic separation, trypsin or chymotrypsin digestion and nano-liquid chromatography-Fourier transform mass spectrometry. When we employed total membrane proteins of Synechocystis sp. PCC 6803, 155 integral membrane proteins out of a predictable 706 were identified in a single application, corresponding to 22% of a genome. The combined methods of acid hydrolysis-trypsin (AT) and acid hydrolysis-chymotrypsin (AC) identified both hydrophilic and hydrophobic domains of integral membrane proteins, respectively. The systematic approach revealed a more concrete data in mapping the repertoire of cyanobacterial membrane and membrane-linked proteome.

  3. Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends.

    PubMed

    Altiparmak, Duran; Keskin, Ali; Koca, Atilla; Gürü, Metin

    2007-01-01

    In this experimental work, tall oil methyl ester-diesel fuel blends as alternative fuels for diesel engines were studied. Tall oil methyl ester was produced by reacting tall oil fatty acids with methyl alcohol under optimum conditions. The blends of tall oil methyl ester-diesel fuel were tested in a direct injection diesel engine at full load condition. The effects of the new fuel blends on the engine performance and exhaust emission were tested. It was observed that the engine torque and power output with tall oil methyl ester-diesel fuel blends increased up to 6.1% and 5.9%, respectively. It was also seen that CO emissions decreased to 38.9% and NO(x) emissions increased up to 30% with the new fuel blends. The smoke opacity did not vary significantly.

  4. Coriander Seed Oil Methyl Esters as Biodiesel Fuel: Unique Fatty Acid Composition and Excellent Oxidative Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coriander (Coriandrum sativum L.) seed oil methyl esters were prepared and evaluated as an alternative biodiesel fuel and contained an unusual fatty acid (FA) hitherto unreported as the principle component in biodiesel fuels: petroselinic (6Z-octadecenoic; 68.5 wt %) acid. Most of the remaining FA...

  5. Selective microbial degradation of saturated methyl branched chain fatty acid isomers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three strains of Pseudomonas bacteria were screened for their capabilities of degrading chemically synthesized saturated branched-chain fatty acids (sbc-FAs). Mixtures of sbc-FAs with the methyl-branch located at various locales along the fatty acid were used as a carbon feedstock in shake-flask cu...

  6. Low-temperature phase behavior of fatty acid methyl esters by differential scanning calorimetry (DSC)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid methyl ester (FAME) mixtures have many uses including biodiesel, lubricants, metal-working fluids, surfactants, polymers, coatings, green solvents and phase-change materials. The physical properties of a FAME mixture depends on the fatty acid concentration (FAC) profile. Some products hav...

  7. 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.

    PubMed

    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.%).

  8. AMP kinase activation with AICAR further increases fatty acid oxidation and blunts triacylglycerol hydrolysis in contracting rat soleus muscle.

    PubMed

    Smith, Angela C; Bruce, Clinton R; Dyck, David J

    2005-06-01

    Muscle contraction increases glucose uptake and fatty acid (FA) metabolism in isolated rat skeletal muscle, due at least in part to an increase in AMP-activated kinase activity (AMPK). However, the extent to which AMPK plays a role in the regulation of substrate utilization during contraction is not fully understood. We examined the acute effects of 5-aminoimidazole-4-carboxamide riboside (AICAR; 2 mm), a pharmacological activator of AMPK, on FA metabolism and glucose oxidation during high intensity tetanic contraction in isolated rat soleus muscle strips. Muscle strips were exposed to two different FA concentrations (low fatty acid, LFA, 0.2 mm; high fatty acid, HFA, 1 mm) to examine the role that FA availability may play in both exogenous and endogenous FA metabolism with contraction and AICAR. Synergistic increases in AMPK alpha2 activity (+45%; P<0.05) were observed after 30 min of contraction with AICAR, which further increased exogenous FA oxidation (LFA: +71%, P<0.05; HFA: +46%, P<0.05) regardless of FA availability. While there were no changes in triacylglycerol (TAG) esterification, AICAR did increase the ratio of FA partitioned to oxidation relative to TAG esterification (LFA: +65%, P<0.05). AICAR significantly blunted endogenous TAG hydrolysis (LFA: -294%, P<0.001; HFA: -117%, P<0.05), but had no effect on endogenous oxidation rates, suggesting a better matching between TAG hydrolysis and subsequent oxidative needs of the muscle. There was no effect of AICAR on the already elevated rates of glucose oxidation during contraction. These results suggest that FA metabolism is very sensitive to AMPK alpha2 stimulation during contraction.

  9. In situ pressurized biphase acid hydrolysis, a promising approach to produce bioactive diosgenin from the tubers of Dioscorea Zingiberensis

    PubMed Central

    Yang, Huan; Yin, Hua-wu; Wang, Xue-wei; Li, Zi-hao; Shen, Yu-ping; Jia, Xiao-bin

    2015-01-01

    Background: The tubers of Dioscorea zingiberensis, is the most favorable plant material for the production of diosgenin, an important bioactive steroidal sapogenin and requisite precursor of cortin, contraceptive and sex hormone, which is the only desired product after steroidal saponins from the tubers are hydrolyzed. Objective: A novel technology, in situ pressurized biphase acid hydrolysis was constructed for the first time to simplify extraction process, increase extraction yield and decrease the consumption of mineral acids. Materials and Methods: The method developed in this study has been optimized and verified through orthogonal design for experiments, in which the effect and their significance of four factors including molarity of acid, temperature, extraction duration and sample quantity have been investigated. Then, the comparison was conducted among the newly developed method and other reported methods. The diosgenin was also isolated by column chromatography, followed by mass spectrometry and nuclear magnetic resonance analysis for structural confirmation. Results: It was found that temperature is the factor of the most influence and the highest extraction yield at 2.21% has been achieved while the hydrolysis was performed at 140°C for 1.5 h in 0.20M H2SO4 solution with petroleum ether under an uncontrolled pressurized condition. And, compared to the others, the increment in the extraction yield of new method was 20.8 ~ 74.0%, and the consumption of H2SO4 was reduced by 17 times at most. Conclusion: This method is a much cleaner and more efficient approach for extraction of diosgenin from the tubers, and is promising to be applied in pharmaceutical industry. PMID:26246743

  10. Progressing batch hydrolysis process

    DOEpatents

    Wright, J.D.

    1985-01-10

    A progressive batch hydrolysis process is disclosed for producing sugar from a lignocellulosic feedstock. It comprises passing a stream of dilute acid serially through a plurality of percolation hydrolysis reactors charged with feed stock, at a flow rate, temperature and pressure sufficient to substantially convert all the cellulose component of the feed stock to glucose. The cooled dilute acid stream containing glucose, after exiting the last percolation hydrolysis reactor, serially fed through a plurality of pre-hydrolysis percolation reactors, charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the hemicellulose component of said feedstock to glucose. The dilute acid stream containing glucose is cooled after it exits the last prehydrolysis reactor.

  11. Hydrolysis of Peptidoglycan is Modulated by Amidation of meso-Diaminopimelic Acid and Mg(2+) in Bacillus subtilis.

    PubMed

    Dajkovic, Alex; Tesson, Benoit; Chauhan, Smita; Courtin, Pascal; Keary, Ruth; Flores, Pierre; Marlière, Christian; Felipe, Sergio; Chapot-Chartier, Marie-Pierre; Carballido-Lopez, Rut

    2017-03-20

    The ability of excess Mg(2+) to compensate the absence of cell wall related genes in Bacillus subtilis has been known for a long time, but the mechanism has remained obscure. Here, we show that the rigidity of wild-type cells remains unaffected with excess Mg(2+) , but the proportion of amidated meso-diaminopimelic (mDAP) acid in their peptidoglycan (PG) is significantly reduced. We identify the amidotransferase AsnB as responsible for mDAP amidation and show that the gene encoding it is essential without added Mg(2+) . Growth without excess Mg(2+) causes ΔasnB mutant cells to deform and ultimately lyse. In cell regions with deformations, PG insertion is orderly and indistinguishable from the wild-type. However, PG degradation is unevenly distributed along the sidewalls. Furthermore, ΔasnB mutant cells exhibit increased sensitivity to antibiotics targeting the cell wall. These results suggest that absence of amidated mDAP causes a lethal deregulation of PG hydrolysis that can be inhibited by increased levels of Mg(2+) . Consistently, we found that Mg(2+) inhibits autolysis of wild-type cells. We suggest that Mg(2+) helps to maintain the balance between PG synthesis and hydrolysis in cell wall mutants where this balance is perturbed in favor of increased degradation. This article is protected by copyright. All rights reserved.

  12. DNA methylation landscape of fat deposits and fatty acid composition in obese and lean pigs

    PubMed Central

    Zhang, Shunhua; Shen, Linyuan; Xia, Yudong; Yang, Qiong; Li, Xuewei; Tang, Guoqing; Jiang, Yanzhi; Wang, Jinyong; Li, Mingzhou; Zhu, Li

    2016-01-01

    Obese and lean type pig breeds exhibit differences in their fat deposits and fatty acid composition. Here, we compared the effect of genome-wide DNA methylation on fatty acid metabolism between Landrace pigs (LP, leaner) and Rongchang pigs (RP, fatty). We found that LP backfat (LBF) had a higher polyunsaturated fatty acid content but a lower adipocyte volume than RP backfat (RBF). LBF exhibited higher global DNA methylation levels at the genome level than RBF. A total of 483 differentially methylated regions (DMRs) were located in promoter regions, mainly affecting olfactory and sensory activity and lipid metabolism. In LBF, the promoters of genes related to ATPase activity had significantly stronger methylation. This fact may suggest lower energy metabolism levels, which may result in less efficient lipid synthesis in LBF. Furthermore, we identified a DMR in the miR-4335 and miR-378 promoters and validated their methylation status by bisulfite sequencing PCR. The hypermethylation of the promoters of miR-4335 and miR-378 in LBF and the resulting silencing of the target genes may result in LBF’s low content in saturated fatty acids and fat deposition capacity. This study provides a solid basis for exploring the epigenetic mechanisms affecting fat deposition and fatty acid composition. PMID:27721392

  13. Molecular weight determination of methyl esters of mycolic acids using thermospray mass spectrometry.

    PubMed

    Ioneda, T; Beaman, B L

    1992-11-01

    Methyl esters of normal fatty acids, corynomycolate and corynomycolenate were used as model compounds for thermospray mass spectrometric procedures for molecular weight determination of the related nocardial mycolic acids. By using ammonium acetate at the positive ion generator, in both cases, a family of ions was produced. The following members were found and corresponded to the adducts: (1) M + H; M + NH4 and M + H + NH4 for methyl esters of normal fatty acids, whereas M + H, M + 2H and M + H + NH4 were the adducts most frequently observed with methyl corynomycolates. The methyl esters of C40-C48 mycolic acids from Rhodococcus rhodochrous exhibited prominent peaks corresponding to adducts M + H + NH4 whereas those corresponding to M + 2H showed slightly lower intensities. The structure M + H had no significant representatives with this subclass of mycolic acids. A similar pattern was observed with methyl esters of C50-C54 mycolic acids from Nocardia asteroides GUH-2. Ion peaks C50-C54 representing adducts M + 2H and M + H + NH4 prevailed in the mass spectrum. In this case, the intensities of peaks corresponding to M + 2H were slightly higher than those of the M + H + NH4. Essentially three main species of nocardomycolic acids were detected: (1) monounsaturated C50:1, C52:1 and C54:1; (2) diunsaturated C50:2, C52:2 and C54:2 and (3) triunsaturated C52:3 and C54:3 mycolic acids. The most abundant mycolic acid was C52:2 followed in decreasing abundance by C52:1, C54:2, C50:2, C52:3 and C54:3 mycolic acids.

  14. 40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acetic acid, , 1-methyl hexyl ester... Substances § 721.304 Acetic acid, , 1-methyl hexyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as acetic acid, -, 1-methylhexyl ester (PMN...

  15. 40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acetic acid, , 1-methyl hexyl ester... Substances § 721.304 Acetic acid, , 1-methyl hexyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as acetic acid, -, 1-methylhexyl ester (PMN...

  16. 40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acetic acid, , 1-methyl hexyl ester... Substances § 721.304 Acetic acid, , 1-methyl hexyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as acetic acid, -, 1-methylhexyl ester (PMN...

  17. 40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acetic acid, , 1-methyl hexyl ester... Substances § 721.304 Acetic acid, , 1-methyl hexyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as acetic acid, -, 1-methylhexyl ester (PMN...

  18. 40 CFR 721.304 - Acetic acid, [(5-chloro-8-quinolinyl)oxy-], 1-methyl hexyl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acetic acid, , 1-methyl hexyl ester... Substances § 721.304 Acetic acid, , 1-methyl hexyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as acetic acid, -, 1-methylhexyl ester (PMN...

  19. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  20. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  1. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  2. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  3. 40 CFR 721.10188 - Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Fatty acids, tall-oil, reaction... Fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine (generic). (a... generically as fatty acids, tall-oil, reaction products with 4-methyl-2-pentanone and aliphatic polyamine...

  4. The Acid Catalyzed Nitration of Methanol: Formation of Methyl Nitrate via Aerosol Chemistry

    NASA Technical Reports Server (NTRS)

    Riffel, Brent G.; Michelsen, Rebecca R.; Iraci, Laura T.

    2004-01-01

    The liquid phase acid catalyzed reaction of methanol with nitric acid to yield methyl nitrate under atmospheric conditions has been investigated using gas phase infrared spectroscopy. This nitration reaction is expected to occur in acidic aerosol particles found in the upper troposphere/lower stratosphere as highly soluble methanol and nitric acid diffuse into these aerosols. Gaseous methyl nitrate is released upon formation, suggesting that some fraction of NO(x) may he liberated from nitric acid (methyl nitrate is later photolyzed to NO(x)) before it is removed from the atmosphere by wet deposition. Thus, this reaction may have important implications for the NO(x) budget. Reactions have been initiated in 45-62 wt% H2SO4 solutions at 10.0 C. Methyl nitrate production rates increased exponentially with acidity within the acidity regime studied. Preliminary calculations suggest that the nitronium ion (NO2(+) is the active nitrating agent under these conditions. The reaction order in methanol appears to depend on the water/methanol ratio and varies from first to zeroth order under conditions investigated. The nitration is first order in nitronium at all acidities investigated. A second order rate constant, kappa(sub 2), has been calculated to be 1 x 10(exp 8)/ M s when the reaction is first order in methanol. Calculations suggest the nitration is first order in methanol under tropospheric conditions. The infinitesimal percentage of nitric acid in the nitronium ion form in this acidity regime probably makes this reaction insignificant for the upper troposphere; however, this nitration may become significant in the mid stratosphere where colder temperatures increase nitric acid solubility and higher sulfuric acid content shifts nitric acid speciation toward the nitronium ion.

  5. Effect of succinic acid and tween-80 on glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine.

    PubMed

    Baranov, P A; Kravtsova, O U; Sariev, A K; Sherdev, V P

    2008-07-01

    We studied the effect of succinic acid on the process of glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine after peroral and intraperitoneal administration in the form of succinate or a base. Since the basic form of 2-ethyl-6-methyl-3-hydroxypyridine is insoluble in water, it was administered in 5% Tween-80. It was necessary to evaluate also the effect of Tween-80 on glucuronidation of 2-ethyl-6-methyl-3-hydroxypyridine in different administration routes. Quantitative assay of glucuronidated fractions was performed by the method of reversed-phase HPLC with fluorometrical detection. The detection limit for this method was 10 ng/ml. We confirmed that the major excretion pathway for 2-ethyl-6-methyl-3-hydroxypyridine is conjugation with glucuronic acid. It was found that succinic acid increased excretion of glucuronidated metabolite after both peroral and intraperitoneal administration of 2-ethyl-6-methyl-3-hydroxypyridine in the form of succinate and base in 5% Tween-80. The effect of Tween-80 was detected only after peroral administration, which was probably related to its effect on absorption of this compound. Tween-80 increased excretion of glucuronate after peroral administration of 2-ethyl-6-methyl-3-hydroxypyridine in the form of succinate and in 5% Tween solution.

  6. Enzymatic hydrolysis of cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) viscera using commercial proteases: effects on lipid distribution and amino acid composition.

    PubMed

    Kechaou, Emna Soufi; Dumay, Justine; Donnay-Moreno, Claire; Jaouen, Pascal; Gouygou, Jean-Paul; Bergé, Jean-Pascal; Amar, Raja Ben

    2009-02-01

    Total lipid and phospholipid recovery as well as amino acid quality and composition from cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) were compared. Enzymatic hydrolyses were performed using the three proteases Protamex, Alcalase, and Flavourzyme by the pH-stat method (24 h, pH 8, 50 degrees C). Three fractions were generated: an insoluble sludge, a soluble aqueous phase, and an oily phase. For each fraction, lipids, phospholipids, and proteins were quantified. Quantitative and qualitative analyses of the raw material and hydrolysates were performed. The degree of hydrolysis (DH) for cuttlefish viscera was 3.2% using Protamex, 6.8% using Flavourzyme, and 7% using Alcalase. DH for sardine viscera was 1.9% (using Flavourzyme), 3.1% (using Protamex) and 3.3% (using Alcalase). Dry matter yields of all hydrolysis reactions increased in the aqueous phases. Protein recovery following hydrolysis ranged from 57.2% to 64.3% for cuttlefish and 57.4% to 61.2% for sardine. Tissue disruption following protease treatment increased lipid extractability, leading to higher total lipid content after hydrolysis. At least 80% of the lipids quantified in the raw material were distributed in the liquid phases for both substrates. The hydrolysed lipids were richer in phospholipids than in the lipids extracted by classical chemical extraction, especially after Flavourzyme hydrolysis for cuttlefish and Alcalase hydrolysis for sardine. The total amino acid content differed according to the substrate and the enzyme used. However, regardless of the raw material or the protease used, hydrolysis increased the level of essential amino acids in the hydrolysates, thereby increasing their potential nutritional value for feed products.

  7. 40 CFR 721.10665 - 2-Propenoic acid, (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10665 2-Propenoic acid, (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl ester. (a) Chemical substance and significant new uses subject to reporting. (1)...

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

    PubMed

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

    2013-02-01

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

  9. Synthesis of C-11-{beta}-aminoisobutyric acid (C-11-{beta}-AlB): A major in vivo catabolite of [methyl-C-11]thymidine

    SciTech Connect

    Alauddin, M.M.; Conti, P.S.; Fissekis, J.D.

    1995-05-01

    Carbon-11 labeled thymidine (TdR) is being used for brain tumor imaging in patients with PET. Following clearance of 5-methyl C-11 TdR from plasma in humans, there is a progressive increase of C-11 activity in normal brain and tumor presumably secondary to accumulation of C-11 beta-AIB, a major by-product of thymidine catabolism in vivo. Canine studies have demonstrated that the major radiolabeled species in acid soluble extracts of brain and tumor tissues during C-14 TdR studies is beta-AIB. The previously reported synthesis of beta-AIB is not suitable for incorporation of carbon-11. A convenient method of synthesis of C-11 beta-AIB was developed where commercially available beta-alanine ethyl ester was converted to the cold precursor reagent, benzaldimine-beta-alanine ethyl ester, in 87% yield. Treatment of the imine derivative with LDA (1.1 eq) in THF at -78{degrees} C, followed by addition of iodomethane (1.1 eq) produced the alpha-methylated benzaldimine-beta-alanine ethyl ester in 73% chemical yield. Deprotection of the amino group by acidic hydrolysis followed by basic hydrolysis of the ester group produced the desired product in 50% chemical yield. Chemical structures of unlabeled intermediates and product were confirmed by H-1 NMR and CI mass spectrometry. Labeling was accomplished using C-11-methyl iodide prepared from C-11-CO{sub 2} according to literature methods. After removal of protecting groups and neutralization, the enatiomeric mixture was purified by HPLC using a semipreparative reverse phase C-18 column and PBS as eluent. The desired compound was eluted at 8.26 minutes. In preliminary runs, the synthesis time was 39 minutes including HPLC purification, with radiochemical yields of 5-6% (EOB). Radiochemical purity was >99%

  10. Semisynthesis of the antiviral abietane diterpenoid jiadifenoic acid C from callitrisic acid (4-epidehydroabietic acid) isolated from sandarac resin.

    PubMed

    González, Miguel A; Zaragozá, Ramón J

    2014-09-26

    The semisynthesis of the antiviral abietane diterpenoid (+)-jiadifenoic acid C starting from the available methyl ester of callitrisic acid (4-epidehydroabietic acid) isolated from sandarac resin is reported. A protocol for the isolation of methyl callitrisate (methyl 4-epidehydroabietate) in gram quantities from sandarac resin is also described. Allylic C-17 oxygenation was introduced by regioselective dehydrogenation of the isopropyl group of methyl callitrisate with DDQ followed by selenium-catalyzed allylic oxidation. Ester hydrolysis afforded (+)-jiadifenoic acid C in 22% overall yield from methyl callitrisate. This semisynthetic route provides a convenient source of this anti-Coxsackie virus B natural product for further biological studies.

  11. Development of an environmentally benign process for the production of fatty acid methyl esters.

    PubMed

    Jordan, V; Gutsche, B

    2001-04-01

    The production of fatty acid methyl esters (FAME) is an important intermediate step in oleochemistry. The oleochemical production route starts with the renewable raw materials fat and oil and ends at fatty alcohols and different special products. Fatty acid methyl esters can be formed at mild reaction temperatures by transesterification of natural triglycerides (fats and oils). This contribution will show the development of a continuous process which is considering the main principles of production integrated environmental protection. The main advantages of this process are low energy consumption and minimal waste production. The process alternatives are shown and a scope on future problems which have to be solved to reach a real additional improvement of the fatty acid methyl esters production is given.

  12. Reversible receptor methylation is essential for normal chemotaxis of Escherichia coli in gradients of aspartic acid.

    PubMed Central

    Weis, R M; Koshland, D E

    1988-01-01

    The chemotaxis of wild-type cells of Escherichia coli and double mutants lacking the methyltransferase and the methylesterase activities of the receptor modification system has been compared in spatial gradients of aspartic acid. Previous studies showing that a chemotactic response can be observed for the mutant raised questions about the role of methylation in the bacterial memory. To clarify the role of methylation, the redistribution of bacteria in stabilized defined gradients of aspartic acid was monitored by light scattering. There was no redistribution of the mutant cells in nonsaturating gradients of aspartic acid, but over the same range these mutant bacteria were observed to respond and to adapt during tethering experiments. In large saturating gradients of aspartate, slight movement of the mutant up the gradient was observed. These results show that dynamic receptor methylation is required for the chemotactic response to gentle gradients of aspartic acid and that methylation resets to zero and is part of the normal wild-type memory. There are certain gradients, however, in which the methylation-deficient mutants show chemotactic ability, thus explaining the apparent anomaly. Images PMID:2829179

  13. Analysis of GTPases carrying hydrophobic amino acid substitutions in lieu of the catalytic glutamine: implications for GTP hydrolysis.

    PubMed

    Mishra, Rajeev; Gara, Sudheer Kumar; Mishra, Shambhavi; Prakash, Balaji

    2005-05-01

    Ras superfamily GTP-binding proteins regulate important signaling events in the cell. Ras, which often serves as a prototype, efficiently hydrolyzes GTP in conjunction with its regulator GAP. A conserved glutamine plays a vital role in GTP hydrolysis in most GTP-binding proteins. Mutating this glutamine in Ras has oncogenic effects, since it disrupts GTP hydrolysis. The analysis presented here is of GTP-binding proteins that are a paradox to oncogenic Ras, since they have the catalytic glutamine (Glncat) substituted by a hydrophobic amino acid, yet can hydrolyze GTP efficiently. We term these proteins HAS-GTPases. Analysis of the amino acid sequences of HAS-GTPases reveals prominent presence of insertions around the GTP-binding pocket. Homology modeling studies suggest an interesting means to achieve catalysis despite the drastic hydrophobic substitution replacing the key Glncat of Ras-like GTPases. The substituted hydrophobic residue adopts a "retracted conformation," where it is positioned away from the GTP, as its role in catalysis would be unproductive. This conformation is further stabilized by interactions with hydrophobic residues in its vicinity. These interacting residues are strongly conserved and hydrophobic in all HAS-GTPases, and correspond to residues Asp92 and Tyr96 of Ras. An experimental support for the "retracted conformation" of Switch II arises from the crystal structures of Ylqf and hGBP1. This conformation allows us to hypothesize that, unlike in classical GTPases, catalytic residues could be supplied by regions other than the Switch II (i.e., either the insertions or a neighboring domain).

  14. Ultrasound in fatty acid chemistry: synthesis of a 1-pyrroline fatty acid ester isomer from methyl ricinoleate.

    PubMed

    Lie Ken Jie, M S; Syed-Rahmatullah, M S; Lam, C K; Kalluri, P

    1994-12-01

    A novel 1-pyrroline fatty acid ester isomer (viz. 8-5-hexyl-1-pyrrolin-2-yl) octanoate) has been synthesized from methyl ricinoleate by two routes with an overall yield of 42 and 30%, respectively. Most of the reactions are carried out under concomitant ultrasonic irradiation (20 KHz, ca. 53 watts/cm2). Under such a reaction condition, the reaction time is considerably shortened, and product yields are high. Dehydrobromination under concomitant ultrasonic irradiation of methyl 9, 10-dibromo-12-hydroxyoctadecanoate with KOH in EtOH furnishes methyl 12-hydroxy-9-octadecynoate (66%) within 15 min. Hydration of the latter under ultrasound with mercury(II)acetate in aqueous tetrahydrofuran yields exclusively methyl 12-hydroxy-9-oxo-octadecanoate (95%) in 30 min. The hydroxy group in the latter compound is transformed to the azido function via the mesylate, and treatment of the azido-oxo intermediate (methyl 12-azido-9-oxooctadecanoate) with Ph3P under ultrasonic irradiation furnishes the requisite 1-pyrroline fatty acid ester (77%). The same azido-oxo intermediate has also been obtained by the oxidation of methyl 12-azido-9-cis-octadecenoate using benzoquinone and a catalytic amount of Pd(II)chloride in aqueous tetrahydrofuran under concomitant ultrasonic irradiation (90 min) to give the product in 45% yield. The latter reaction does not take place even under prolonged silent stirring of the reaction mixture.

  15. Relationships between the resistance of yeasts to acetic, propanoic and benzoic acids and to methyl paraben and pH.

    PubMed

    Warth, A D

    1989-07-01

    Minimum inhibitory concentrations of acetic, propanoic and benzoic acids and methyl paraben were determined at pH 3.50 for 22 isolates of 11 yeast species, differing in their resistance to preservatives. Growth in the presence of benzoic acid enhanced the resistance of yeasts to benzoic and the other weak acid preservatives, but not to methyl paraben. Resistance to acetic, propanoic and benzoic acids was strongly correlated, but was not closely related to resistance to methyl paraben. Minimum pH for growth was not related to resistance to the weak acids. The results suggest that growth in the presence of weak-acid preservatives involves a common resistance mechanism.

  16. Occurrence and human exposure of p-hydroxybenzoic acid esters (parabens), bisphenol A diglycidyl ether (BADGE), and their hydrolysis products in indoor dust from the United States and three East Asian countries.

    PubMed

    Wang, Lei; Liao, Chunyang; Liu, Fang; Wu, Qian; Guo, Ying; Moon, Hyo-Bang; Nakata, Haruhiko; Kannan, Kurunthachalam

    2012-11-06

    p-Hydroxybenzoic acid esters (parabens) and bisphenol A diglycidyl ether (BADGE) are widely present in personal care products, food packages, and material coatings. Nevertheless, little is known about the occurrence of these compounds in indoor dust. In this study, we collected 158 indoor dust samples from the U.S., China, Korea, and Japan and determined the concentrations of 11 target chemicals, viz., six parabens and their common hydrolysis product, 4-hydroxybenzoic acid (4-HB), as well as BADGE and its three hydrolysis products (BADGE·H(2)O, BADGE·2H(2)O, and BADGE·HCl·H(2)O). All of the target compounds were found in dust samples from four countries. Concentrations of sum of six parabens in dust were on the order of several hundred to several thousands of nanogram per gram. Geometric mean concentrations of BADGEs in dust ranged from 1300 to 2890 ng/g among four countries. Methyl paraben (MeP), propyl paraben (PrP), BADGE·2H(2)O, and BADGE·HCl·H(2)O were the predominant compounds found in dust samples. This is the first report of BADGE and its hydrolysis products (BADGEs) in indoor dust samples and of parabens in indoor dust from Asian countries. On the basis of the measured concentrations of target chemicals, we estimated the daily intake (EDI) via dust ingestion. The EDIs of parabens via dust ingestion were 5-10 times higher in children than in adults. Among the four countries studied, the EDIs of parabens (5.4 ng/kg-bw/day) and BADGEs (6.5 ng/kg-bw/day) through dust ingestion were the highest for children in Korea and Japan.

  17. Hydrolysis of ionized deoxycholic acid in the aqueous phase and rate analysis for transfer of neutralized deoxycholic acid into the benzene phase across the benzene/water interface.

    PubMed

    Ohno, Ryo; Nakamura, Shohei; Moroi, Yoshikiyo; Isoda-Yamashita, Teruyo

    2008-11-13

    Sodium deoxycholate in water dissociates into sodium cation and deoxycholate anion in the aqueous phase, and then, the latter anions partially hydrolyze to form deionized deoxycholic acids. The acids move into the benzene phase, when liquid benzene is placed upon the aqueous phase, and finally the partition equilibrium is reached. The above processes were traced by pH change in the aqueous phase by a pH meter or the change in [OH-] with time, from which the rate for transfer of neutralized acid to the organic phase was analyzed. From the trace, the rate constants for hydrolysis of acid anion ( kf), neutralization of acid ( kb), transfer of neutralized acid from the aqueous phase to the organic phase ( kin*), and its back-transfer from the organic phase to the aqueous phase ( kut*) were evaluated; kf = 2.18 x 10 (-4) mol (-1) dm (3) min (-1), kb = 1.24 x 10 (5) mol (-1) dm (3) min (-1), kin* = 4.06 x 10 (-1) min (-1) cm (-2), and kout*) = 8.00 x 10 (-2) min (-1) cm (-2). The above values are supported by the partition constant of deoxycholic acid between the benzene phase and the aqueous phase.

  18. Methylation of acidic moieties in poly(methyl methacrylate-co-methacrylic acid) copolymers for end-group characterization by tandem mass spectrometry.

    PubMed

    Giordanengo, Rémi; Viel, Stéphane; Hidalgo, Manuel; Allard-Breton, Béatrice; Thévand, André; Charles, Laurence

    2010-07-30

    The complete structural characterization of a copolymer composed of methacrylic acid (MAA) and methyl methacrylate (MMA) units was achieved using tandem mass spectrometry. In a first step, collision-induced dissociation (CID) of sodiated MAA-MMA co-oligomers allowed us to determine the co-monomeric composition, the random nature of the copolymer and the sum of the end-group masses. However, dissociation reactions of MAA-based molecules mainly involve the acidic pendant groups, precluding individual characterization of the end groups. Therefore, methylation of all the acrylic acid moieties was performed to transform the MAA-MMA copolymer into a PMMA homopolymer, for which CID mainly proceeds via backbone cleavages. Using trimethylsilyldiazomethane as a derivatization agent, this methylation reaction was shown to be complete without affecting the end groups. Using fragmentation rules established for PMMA polymers together with accurate mass measurements of the product ions and knowledge of reagents used for the studied copolymer synthesis, a structure could be proposed for both end groups and it was found to be consistent with signals obtained in nuclear magnetic resonance spectra.

  19. Standardizing methylation method during phospholipid fatty acid analysis to profile soil microbial communities.

    PubMed

    Chowdhury, Taniya Roy; Dick, Richard P

    2012-02-01

    Phospholipid fatty acid (PLFA) as biomarkers, is widely used to profile microbial communities in environmental samples. However, PLFA extraction and derivatization protocols are not standardized and have widely varied among published studies. Specifically investigators have used either HCl/MeOH or KOH/MeOH or both for the methylation step of PLFA analysis, without justification or research to support either one. It seems likely that each method could have very different outcomes and conclusions for PLFA based studies. Therefore, the objective of this study was to determine the effect of catalyst type for methylation on detecting PLFAs and implications for interpreting microbial profiling in soil. Fatty acid samples extracted from soils obtained from a wetland, an intermittently flooded site, and an adjacent upland site were subjected to HCl/MeOH or KOH/MeOH catalyzed methylation procedures during PLFA analyses. The methylation method using HCl/MeOH resulted in significantly higher concentrations of most PLFAs than the KOH/MeOH method. Another important outcome was that fatty acids with a methyl group (18:1ω,7c 11Me, TBSA 10Me 18:0, 10Me 18:0, 17:0 10Me and 16:0 10Me being an actinomycetes biomarker) could not be detected by HCl/MeOH catalyzed methylation but were found in appreciable concentrations with KOH/MeOH method. From our results, because the HCl/MeOH method did not detect the fatty acids containing methyl groups that could strongly influence the microbial community profile, we recommend that the KOH/MeOH catalyzed transesterification method should become the standard procedure for PLFA profiling of soil microbial communities.

  20. The effect of several organic acids on phytate phosphorus hydrolysis in broiler chicks.

    PubMed

    Liem, A; Pesti, G M; Edwards, H M

    2008-04-01

    Supplementation of some organic acids to a P-deficient diet has been shown to improve phytate P utilization. Two experiments were conducted from 0 to 16 d in battery brooders to determine the effect of various organic acids supplementation on phytate P utilization. In both experiments, birds were fed P-deficient corn and soybean meal-based diets. In experiment 1, citric acid, malic acid, fumaric acid, and EDTA were supplemented. Experiment 2 had a 2 x 2 factorial design with 2 sources of Met, 2-hydroxy-4-(methylthio) butanoic acid (HMB) and dl-Met, with or without 500 U/kg of phytase. In experiment 1, the addition of citric, malic, and fumaric acids increased percentage of bone ash, but only the effect of citric acid was significant. The addition of citric and malic acids also significantly increased the retention of P and phytate P (P<0.05). In experiment 2, the addition of phytase to the diet significantly increased 16-d BW gain, feed intake, percentage of bone ash, milligrams of bone ash, phytate P disappearance, and decreased the incidence of P-deficiency rickets. Methionine source did not affect 16-d BW gain, feed intake, feed efficiency, milligrams of bone ash, or P rickets incidence. However, the birds fed HMB had a higher percentage of bone ash and phytate P disappearance compared with the groups fed dl-Met only when phytase was added to the diets. The additions of citric acid and HMB improved phytate P utilization. However, the reason why some organic acids are effective whereas others are not is not apparent.

  1. Synthesis of (S)-ricinoleic acid and its methyl ester with the participation of ionic liquid.

    PubMed

    Kula, Józef; Bonikowski, Radoslaw; Szewczyk, Malgorzata; Ciolak, Kornelia

    2014-10-01

    (R)-ricinoleic acid methyl ester obtained from commercial castor oil was transformed in a three-step procedure into its S-enantiomer in overall 36% yield using ionic liquid (1-butyl-3-methylimidazolium acetate) in the key step process. The developed procedure provides easy access to (S)-ricinoleic acid and its methyl ester of over 95% enantiomeric excess. Optical rotations of the newly obtained compounds as well as their chromatographic and spectral characteristics are provided and discussed in the context of enantiopurity both of the substrate material and the final products.

  2. Antimicrobial activity of fatty acid methyl esters of some members of Chenopodiaceae.

    PubMed

    Chandrasekaran, Manivachagam; Kannathasan, Krishnan; Venkatesalu, Venugopalan

    2008-01-01

    Fatty acid methyl ester (FAME) extracts of four halophytic plants, viz. Arthrocnemum indicum, Salicornia brachiata, Suaeda maritima and Suaeda monoica belonging to the family Chenopodiaceae, were prepared and their composition was analyzed by GC-MS. The FAME extracts were also screened for antibacterial and antifungal activities. The GC-MS analysis revealed the presence of more saturated fatty acids than unsaturated fatty acids. Among the fatty acids analyzed, the relative percentage of lauric acid was high in S. brachiata (61.85%). The FAME extract of S. brachiata showed the highest antibacterial and antifungal activities among the extracts tested. The other three extracts showed potent antibacterial and moderate anticandidal activities.

  3. Conformational free energies of methyl-α-L-iduronic and methyl-β-D-glucuronic acids in water

    NASA Astrophysics Data System (ADS)

    Babin, Volodymyr; Sagui, Celeste

    2010-03-01

    We present a simulation protocol that allows for efficient sampling of the degrees of freedom of a solute in explicit solvent. The protocol involves using a nonequilibrium umbrella sampling method, in this case, the recently developed adaptively biased molecular dynamics method, to compute an approximate free energy for the slow modes of the solute in explicit solvent. This approximate free energy is then used to set up a Hamiltonian replica exchange scheme that samples both from biased and unbiased distributions. The final accurate free energy is recovered via the weighted histogram analysis technique applied to all the replicas, and equilibrium properties of the solute are computed from the unbiased trajectory. We illustrate the approach by applying it to the study of the puckering landscapes of the methyl glycosides of α-L-iduronic acid and its C5 epimer β-D-glucuronic acid in water. Big savings in computational resources are gained in comparison to the standard parallel tempering method.

  4. Titan's primordial soup: formation of amino acids via low-temperature hydrolysis of tholins.

    PubMed

    Neish, Catherine D; Somogyi, Arpád; Smith, Mark A

    2010-04-01

    Titan organic haze analogues, or "tholins," produce biomolecules when hydrolyzed at low temperature over long timescales. By using a combination of high-resolution mass spectroscopy and tandem mass spectrometry fragmentation techniques, four amino acids were identified in a tholin sample that had been hydrolyzed in a 13 wt % ammonia-water solution at 253 + or - 1 K and 293 + or - 1 K for 1 year. These four species have been assigned as the amino acids asparagine, aspartic acid, glutamine, and glutamic acid. This represents the first detection of biologically relevant molecules created under conditions thought to be similar to those found in impact melt pools and cryolavas on Titan, which are at a stage of chemical evolution not unlike the "primordial soup" of the early Earth. Future missions to Titan should therefore carry instrumentation capable of, but certainly not limited to, detecting amino acids and other prebiotic molecules on Titan's surface.

  5. Titan's Primordial Soup: Formation of Amino Acids via Low-Temperature Hydrolysis of Tholins

    NASA Astrophysics Data System (ADS)

    Neish, Catherine D.; Somogyi, Árpád; Smith, Mark A.

    2010-04-01

    Titan organic haze analogues, or "tholins," produce biomolecules when hydrolyzed at low temperature over long timescales. By using a combination of high-resolution mass spectroscopy and tandem mass spectrometry fragmentation techniques, four amino acids were identified in a tholin sample that had been hydrolyzed in a 13 wt % ammonia-water solution at 253 ± 1 K and 293 ± 1 K for 1 year. These four species have been assigned as the amino acids asparagine, aspartic acid, glutamine, and glutamic acid. This represents the first detection of biologically relevant molecules created under conditions thought to be similar to those found in impact melt pools and cryolavas on Titan, which are at a stage of chemical evolution not unlike the "primordial soup" of the early Earth. Future missions to Titan should therefore carry instrumentation capable of, but certainly not limited to, detecting amino acids and other prebiotic molecules on Titan's surface.

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

    PubMed

    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.

  7. Aroma components of acid-hydrolyzed vegetable protein made by partial hydrolysis of rice bran protein.

    PubMed

    Jarunrattanasri, Arporn; Theerakulkait, Chockchai; Cadwallader, Keith R

    2007-04-18

    Hydrolyzed vegetable protein (HVP) was prepared from rice bran protein concentrate (RBPc) by partial hydrolysis with aqueous 0.5 N HCl at 95 degrees C for 12 or 36 h (H-RBPc-12 and H-RBPc-36, respectively). Aroma components of the RBPc and the HVPs were characterized by gas chromatography-olfactometry, gas chromatography-mass spectrometry, aroma extract dilution analysis, and calculation of odor activity values (OAVs). The predominant odorants in RBPc were 3-methylbutanal, hexanal, 2-aminoacetophenone, (E)-2-nonenal, phenylacetaldehyde, and beta-damascenone. Among these, the odor of 2-aminoacetophenone, present at 59 ng/g in RBPc, was reminiscent of the typical odor of RBPc. Most of the predominant odorants had higher log3FD factors in the H-RBPc-36 as compared to H-RBPc-12. Aroma impact compounds of H-RBPc-12 and H-RBPc-36 were 2-methoxyphenol (guaiacol), 4-hydroxy-2,5-dimethyl-3(2H)furanone, 3-hydroxy-4,5-dimethyl-2(5H)furanone (sotolon), vanillin, 3-methylbutanal, (E)-2-nonenal, 4-vinyl-2-methoxyphenol (p-vinylguaiacol), and beta-damascenone. Guaiacol had the highest OAV values of 2770 and 17650 in H-RBPc-12 and H-RBPc-36, respectively.

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

    PubMed

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

    2015-02-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed

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

    2015-12-01

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

  11. Progressing batch hydrolysis process

    DOEpatents

    Wright, John D.

    1986-01-01

    A progressive batch hydrolysis process for producing sugar from a lignocellulosic feedstock, comprising passing a stream of dilute acid serially through a plurality of percolation hydrolysis reactors charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the cellulose component of the feedstock to glucose; cooling said dilute acid stream containing glucose, after exiting the last percolation hydrolysis reactor, then feeding said dilute acid stream serially through a plurality of prehydrolysis percolation reactors, charged with said feedstock, at a flow rate, temperature and pressure sufficient to substantially convert all the hemicellulose component of said feedstock to glucose; and cooling the dilute acid stream containing glucose after it exits the last prehydrolysis reactor.

  12. Phospholipidic signaling and vanillin production in response to salicylic acid and methyl jasmonate in Capsicum chinense J. cells.

    PubMed

    Altúzar-Molina, Alma R; Muñoz-Sánchez, J Armando; Vázquez-Flota, Felipe; Monforte-González, Miriam; Racagni-Di Palma, Graciela; Hernández-Sotomayor, S M Teresa

    2011-02-01

    The phospholipidic signal transduction system involves generation of second messengers by hydrolysis or changes in phosphorylation state. Several studies have shown that the signaling pathway forms part of plant response to phytoregulators such as salicylic acid (SA) and methyl jasmonate (MJ), which have been widely used to stimulate secondary metabolite production in cell cultures. An evaluation was made of the effect of SA and MJ on phospholipidic signaling and capsaicinoid production in Capsicum chinense Jacq. suspension cells. Treatment with SA inhibited phospholipase C (PLC) (EC: 3.1.4.3) and phospholipase D (PLD) (EC: 3.1.4.4) activities in vitro, but increased lipid kinase activities in vitro at different SA concentrations. Treatment with MJ produced increases in PLC and PLD activities, while lipid kinase activities were variable and dose-dependent. The production of vanillin, a precursor of capsaicinoids, increased at specific SA or MJ doses. Preincubation with neomycin, a phospholipase inhibitor, before SA or MJ treatment inhibits increase in vanillin production which suggests that phospholipidic second messengers may participate in the observed increase in vanillin production.

  13. Enzymatic hydrolysis and fermentation of pretreated cashew apple bagasse with alkali and diluted sulfuric Acid for bioethanol production.

    PubMed

    Rocha, Maria Valderez Ponte; Rodrigues, Tigressa Helena Soares; de Macedo, Gorete Ribeiro; Gonçalves, Luciana R B

    2009-05-01

    The aim of this work was to optimize the enzymatic hydrolysis of the cellulose fraction of cashew apple bagasse (CAB) after diluted acid (CAB-H) and alkali pretreatment (CAB-OH), and to evaluate its fermentation to ethanol using Saccharomyces cerevisiae. Glucose conversion of 82 +/- 2 mg/g CAB-H and 730 +/- 20 mg/g CAB-OH was obtained when 2% (w/v) of solid and 30 FPU/g bagasse was used during hydrolysis at 45 degrees C, 2-fold higher than when using 15 FPU/g bagasse, 44 +/- 2 mg/g CAB-H, and 450 +/- 50 mg/g CAB-OH, respectively. Ethanol concentration and productivity, achieved after 6 h of fermentation, were 20.0 +/- 0.2 g L(-1) and 3.33 g L(-1) h(-1), respectively, when using CAB-OH hydrolyzate (initial glucose concentration of 52.4 g L(-1)). For CAB-H hydrolyzate (initial glucose concentration of 17.4 g L(-1)), ethanol concentration and productivity were 8.2 +/- 0.1 g L(-1) and 2.7 g L(-1) h(-1) in 3 h, respectively. Hydrolyzates fermentation resulted in an ethanol yield of 0.38 and 0.47 g/g glucose with pretreated CAB-OH and CAB-H, respectively. Ethanol concentration and productivity, obtained using CAB-OH hydrolyzate, were close to the values obtained in the conventional ethanol fermentation of cashew apple juice or sugar cane juice.

  14. Design and synthesis of N-benzoyl amino acid derivatives as DNA methylation inhibitors.

    PubMed

    Garella, Davide; Atlante, Sandra; Borretto, Emily; Cocco, Mattia; Giorgis, Marta; Costale, Annalisa; Stevanato, Livio; Miglio, Gianluca; Cencioni, Chiara; Fernández-de Gortari, Eli; Medina-Franco, José L; Spallotta, Francesco; Gaetano, Carlo; Bertinaria, Massimo

    2016-11-01

    The inhibition of human DNA Methyl Transferases (DNMT) is a novel promising approach to address the epigenetic dysregulation of gene expression in different diseases. Inspired by the validated virtual screening hit NSC137546, a series of N-benzoyl amino acid analogues was synthesized and obtained compounds were assessed for their ability to inhibit DNMT-dependent DNA methylation in vitro. The biological screening allowed the definition of a set of preliminary structure-activity relationships and the identification of compounds promising for further development. Among the synthesized compounds, L-glutamic acid derivatives 22, 23, and 24 showed the highest ability to prevent DNA methylation in a total cell lysate. Compound 22 inhibited DNMT1 and DNMT3A activity in a concentration-dependent manner in the micromolar range. In addition, compound 22 proved to be stable in human serum and it was thus selected as a starting point for further biological studies.

  15. Development of C-reactive protein certified reference material NMIJ CRM 6201-b: optimization of a hydrolysis process to improve the accuracy of amino acid analysis.

    PubMed

    Kato, Megumi; Kinumi, Tomoya; Yoshioka, Mariko; Goto, Mari; Fujii, Shin-Ichiro; Takatsu, Akiko

    2015-04-01

    To standardize C-reactive protein (CRP) assays, the National Metrology Institute of Japan (NMIJ) has developed a C-reactive protein solution certified reference material, CRM 6201-b, which is intended for use as a primary reference material to enable the SI-traceable measurement of CRP. This study describes the development process of CRM 6201-b. As a candidate material of the CRM, recombinant human CRP solution was selected because of its higher purity and homogeneity than the purified material from human serum. Gel filtration chromatography was used to examine the homogeneity and stability of the present CRM. The total protein concentration of CRP in the present CRM was determined by amino acid analysis coupled to isotope-dilution mass spectrometry (IDMS-AAA). To improve the accuracy of IDMS-AAA, we optimized the hydrolysis process by examining the effect of parameters such as the volume of protein samples taken for hydrolysis, the procedure of sample preparation prior to the hydrolysis, hydrolysis temperature, and hydrolysis time. Under optimized conditions, we conducted two independent approaches in which the following independent hydrolysis and liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) were combined: one was vapor-phase acid hydrolysis (130 °C, 24 h) and hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) method, and the other was microwave-assisted liquid-phase acid hydrolysis (150 °C, 3 h) and pre-column derivatization liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The quantitative values of the two different amino acid analyses were in agreement within their uncertainties. The certified value was the weighted mean of the results of the two methods. Uncertainties from the value-assignment method, between-method variance, homogeneity, long-term stability, and short-term stability were taken into account in evaluating the uncertainty for a certified value. The certified value and the

  16. An enhanced procedure for measuring organic acids and methyl esters in PM2.5

    NASA Astrophysics Data System (ADS)

    Liu, F.; Duan, F.; He, K.; Ma, Y.; Rahn, K. A.; Zhang, Q.

    2015-03-01

    We have developed an enhanced analytical procedure to measure organic acids and methyl esters in fine aerosol with much greater specificity and sensitivity than previously available. This capability is important because of these species and their low concentrations, even in highly polluted atmospheres like Beijing, China. The procedure first separates the acids and esters from the other organic compounds with anion-exchange solid- phase extraction (SPE), then, quantifies them by gas chromatography coupled with mass spectrometry. This allows us to accurately quantify the C4-C11 dicarboxylic and the C8-C30 monocarboxylic acids. Then the acids are separated from the esters on an aminopropyl SPE cartridge, whose weak retention isolates and enriches the acids from esters prevents the fatty acids and dimethyl phthalate from being overestimated. The resulting correlations between the aliphatic acids and fatty acid methyl esters (FAMEs) suggest that FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. In all, 17 aromatic acids were identified and quantified using this procedure coupled with gas chromatography-tandem mass spectrometry, including the five polycyclic aromatic hydrocarbon (PAH) acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH-acids and the dicarboxylic and aromatic acids indicated that the first three acids and 1,8-naphthalic anhydride were mainly secondary, the last two mainly primary.

  17. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  18. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  19. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  20. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  1. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  2. 21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... from edible fats and oils. 172.225 Section 172.225 Food and Drugs FOOD AND DRUG ADMINISTRATION... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to...

  3. 21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Methyl esters of conjugated linoleic acid (cis-9... § 573.637 Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic acids). The food additive, methyl esters of conjugated linoleic acid (cis-9, trans-11 and...

  4. Dependence of RIG-I Nucleic Acid-Binding and ATP Hydrolysis on Activation of Type I Interferon Response

    PubMed Central

    Baek, Yu Mi; Yoon, Soojin; Hwang, Yeo Eun

    2016-01-01

    Exogenous nucleic acids induce an innate immune response in mammalian host cells through activation of the retinoic acid-inducible gene I (RIG-I). We evaluated RIG-I protein for RNA binding and ATPase stimulation with RNA ligands to investigate the correlation with the extent of immune response through RIG-I activation in cells. RIG-I protein favored blunt-ended, double-stranded RNA (dsRNA) ligands over sticky-ended dsRNA. Moreover, the presence of the 5'-triphosphate (5'-ppp) moiety in dsRNA further enhanced binding affinity to RIG-I. Two structural motifs in RNA, blunt ends in dsRNA and 5'-ppp, stimulated the ATP hydrolysis activity of RIG-I. These structural motifs also strongly induced IFN expression as an innate immune response in cells. Therefore, we suggest that IFN induction through RIG-I activation is mainly determined by structural motifs in dsRNA that increase its affinity for RIG-I protein and stimulate ATPase activity in RIG-I. PMID:27574504

  5. Effect of methyl jasmonate, salicylic acid, Headline and Stadium on sucrose yield and storage properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl jasmonate (MeJA) and salicylic acid (SA) have been reported to enhance yield and protect crop plants and products against abiotic stresses and diseases. The effect of these compounds on sugarbeets, however, is unknown. Research was conducted in 2015 and 2016 to investigate the effects of an e...

  6. Cold flow properties of fatty acid methyl esters: Additives versus diluents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is typically composed of fatty acid methyl esters (FAME) converted from agricultural lipids. Common feedstocks include soybean oil, canola oil, rapeseed oil, sunflower oil, and palm oil. Recent debate on the conversion of edible oils into non-food products has created opportunities to deve...

  7. Catalytic synthesis of fatty acid methyl esters from extremely low quality greases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel (BD) is a renewable fuel for compression ignition engines that is composed of the simple alkyl esters, usually methyl-, of fatty acids (FAME). It is typically produced via base-catalyzed transesterification between refined vegetable oil or animal fat (e.g., soybean oil, tallow) and an alc...

  8. Prediction of preweaning ADG in beef calves from milk fatty acid methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research has shown milk yield (MWT) has an important influence on calf preweaning ADG (PRWADG), but MWT accounts for only a moderate amount of variation in PRWADG. The objective of this study was to determine if milk fatty acid methyl esters (FAME), alone and in combination with MWT, could improve a...

  9. Chemically Modified Fatty Acid Methyl Esters: Potential as Lubricant and Surfactant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Renewable raw materials are going to play a noteworthy role in the development of sustainable green chemistry because of their eco-friendly and non-toxic nature. A novel process was developed for the production of biodegradable lubricant base stocks from epoxidized fatty acid methyl esters and comm...

  10. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    EPA Science Inventory

    Plasmid DNA damage caused by methylated arsenicals, ascorbic acid and human liver ferritin.

    Arsenic causes cancer in human skin, urinary bladder, lung, liver and kidney and is a significant world-wide public health problem. Although the metabolism of inorganic arsenic is ...

  11. Esterification and Transesterification of greases to fatty acid methyl esters with highly active diphenylamine salts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diphenylamine sulfate (DPAS) and diphenylamine hydrochloride (DPACl) salts were found to be highly active catalysts for esterification and transesterification of inexpensive greases to fatty acid methyl esters (FAME). In the presence of catalytic amounts of DPAS or DPACl and excess methanol, the fr...

  12. Esterification and transesterification of greases to fatty acid methyl esters with highly active diphanylammonium salts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have conducted an investigation designed to identify alternate catalysts for the production of fatty acid methyl esters (FAME) to be used as biodiesel. Diphenylammonium sulfate (DPAS) and diphenylammonium chloride (DPA-HCl) salts were found to be highly active homogeneous catalysts for the simu...

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

    PubMed

    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), the k(1obs) values remained constant k(1obs)(av) = 1.6 x 10(-3) s(-1) and the set of k(2obs) values nicely matched an A-SE2 mechanism, yielding a rate-determining constant k(0,ASE2) = 2.4 x 10(-7) M(-1) s(-1). In region II ([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.

  14. Separation and quantitation of free fatty acids and fatty acid methyl esters by reverse phase high pressure liquid chromatography.

    PubMed

    Aveldano, M I; VanRollins, M; Horrocks, L A

    1983-01-01

    Reverse phase high pressure liquid chromatography (HPLC) on octadecylsilyl columns separates mixtures of either free fatty acids or fatty acid methyl esters prepared from mammalian tissue phospholipids. Acetonitrile-water mixtures are used for the elution of esters. Aqueous phosphoric acid is substituted for water for the separation of the free acids. Unsaturated compounds are detected and quantitated by their absorption at 192 nm. Saturates are detected better at 205 nm. The order of elution of fatty acids in complex mixtures varies as a function of acetonitrile concentration. At any given concentration, some compounds overlap. However, by varying the solvent strength, any fatty acid of interest can be resolved including many geometrical and positional isomers. Methyl esters prefractionated according to unsaturation by argentation thin-layer chromatography (TLC) are rapidly and completely separated by elution with CH3CN alone. Argentation TLC-reverse phase HPLC can be used as an analytical as well as a preparative procedure. Octylsilyl columns are used for rapid resolution and improved detection of minor or low ultraviolet-absorbing components in the fractions. For example, monoenoic fatty acids with up to 32 carbons have been detected in bovine brain glycerophospholipids. Specific radioactivities of 3H- and 14C-labeled fatty acids and the distribution of radioactivity among acyl groups from complex lipids are measured. The method is not recommended for complete compositional analysis, but is useful for determinations of specific radioactivities during studies on turnover and metabolic conversions of labeled fatty acids.

  15. An enhanced procedure for measuring organic acids and methyl esters in PM2.5

    NASA Astrophysics Data System (ADS)

    Liu, F.; Duan, F. K.; He, K. B.; Ma, Y. L.; Rahn, K. A.; Zhang, Q.

    2015-11-01

    A solid-phase extraction (SPE) pretreatment procedure allowing organic acids to be separated from methyl esters in fine aerosol has been developed. The procedure first separates the organic acids from fatty acid methyl esters (FAMEs) and other nonacid organic compounds by aminopropyl-based SPE cartridge and then quantifies them by gas chromatography/mass spectrometry. The procedure prevents the fatty acids and dimethyl phthalate from being overestimated, and so allows us to accurately quantify the C4-C11 dicarboxylic acids (DCAs) and the C8-C30 monocarboxylic acids (MCAs). Results for the extraction of DCAs, MCAs, and AMAs in eluate and FAMEs in effluate by SAX and NH2 SPE cartridges exhibited that the NH2 SPE cartridge gave higher extraction efficiency than the SAX cartridge. The recoveries of analytes ranged from 67.5 to 111.3 %, and the RSD ranged from 0.7 to 10.9 %. The resulting correlations between the aliphatic acids and FAMEs suggest that the FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. Through extraction and cleanup using this procedure, 17 aromatic acids in eluate were identified and quantified by gas chromatography/tandem mass spectrometry, including five polycyclic aromatic hydrocarbon (PAH): acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH acids and the dicarboxylic and aromatic acids suggested that the first three acids and 1,8-naphthalic anhydride were secondary atmospheric photochemistry products and the last two mainly primary.

  16. Titan's Primordial Soup: Formation of Amino Acids via Low Temperature Hydrolysis of Tholins

    NASA Astrophysics Data System (ADS)

    Neish, Catherine; Somogyi, Á.; Smith, M. A.

    2009-09-01

    Titan, Saturn's largest moon, is a world rich in the "stuff of life". Reactions occurring in its dense nitrogen-methane atmosphere produce a wide variety of organic molecules, which subsequently rain down onto its surface. Water - thought to be another important ingredient for life - is likewise abundant on Titan. Theoretical models of Titan's formation predict that its interior consists of an ice I layer several tens of kilometers thick overlying a liquid ammonia-rich water layer several hundred kilometers thick (Tobie et al., 2005). Though its surface temperature of 94K dictates that Titan is on average too cold for liquid water to persist at its surface, melting caused by impacts and/or cryovolcanism may lead to its episodic availability. Impact melt pools on Titan would likely remain liquid for 102 - 104 years before freezing (O'Brien et al., 2005). The combination of complex organic molecules and transient locales of liquid water make Titan an interesting natural laboratory for studying prebiotic chemistry. In this work, we sought to determine what biomolecules might be formed under conditions analogous to those found in transient liquid water environments on Titan. We hydrolyzed Titan organic haze analogues, or "tholins", in 13 wt. % ammonia-water at 253K and 293K for a year. Using a combination of high resolution mass spectroscopy and tandem mass spectroscopy fragmentation techniques, four amino acids were identified in the hydrolyzed tholin sample. These four species have been assigned as the amino acids asparagine, aspartic acid, glutamine, and glutamic acid. This represents the first detection of biologically relevant molecules created under conditions similar to those found in impact melt pools and cryolavas on Titan. Future missions to Titan should therefore carry instrumentation capable of detecting amino acids and other prebiotically relevant molecules on its surface This work was supported by the NASA Exobiology Program.

  17. Transferable force field for carboxylate esters: application to fatty acid methylic ester phase equilibria prediction.

    PubMed

    Ferrando, Nicolas; Lachet, Véronique; Boutin, Anne

    2012-03-15

    In this work, a new transferable united-atoms force field for carboxylate esters is proposed. All Lennard-Jones parameters are reused from previous parametrizations of the AUA4 force field, and only a unique set of partial electrostatic charges is introduced for the ester chemical function. Various short alkyl-chain esters (methyl acetate, ethyl acetate, methyl propionate, ethyl propionate) and two fatty acid methylic esters (methyl oleate and methyl palmitate) are studied. Using this new force field in Monte Carlo simulations, we show that various pure compound properties are accurately predicted: saturated liquid densities, vapor pressures, vaporization enthalpies, critical properties, liquid-vapor surface tensions. Furthermore, a good accuracy is also obtained in the prediction of binary mixture pressure-composition diagrams, without introducing empirical binary interaction parameters. This highlights the transferability of the proposed force field and gives the opportunity to simulate mixtures of industrial interest: a demonstration is performed through the simulation of the methyl oleate + methanol mixture involved in the purification sections of biodiesel production processes.

  18. DNA Methylation of Cellular Retinoic Acid-Binding Proteins in Cervical Cancer.

    PubMed

    Arellano-Ortiz, Ana L; Salcedo-Vargas, Mauricio; Vargas-Requena, Claudia L; López-Díaz, José A; De la Mora-Covarrubias, Antonio; Silva-Espinoza, Juan C; Jiménez-Vega, Florinda

    2016-01-01

    This study determined the methylation status of cellular retinoic acid-binding protein (CRABP) gene promoters and associated them with demographic characteristics, habits, and the presence of human papilloma virus (HPV) in patients with cervical cancer (CC), low and high squamous intraepithelial lesions, and no intraepithelial lesion. Women (n = 158) were selected from the Colposcopy Clinic of Sanitary Jurisdiction II in Ciudad Juarez, Chihuahua, Mexico. Demographic characteristics and habit information were collected. Cervical biopsy and endocervical scraping were used to determine methylation in promoter regions by methylation-specific polymerase chain reaction technique. We found hemi-methylation patterns in the promoter regions of CRABP1 and CRABP2; there was 28.5% hemi-methylation in CRABP1 and 7.0% in that of CRABP2. Methylation in CRABP1 was associated with age (≥35 years, P = 0.002), family history of cancer (P = 0.032), the presence of HPV-16 (P = 0.013), and no alcohol intake (P = 0.035). These epigenetic changes could be involved in the CC process, and CRABP1 has the potential to be a predictive molecular marker of retinoid therapy response.

  19. DNA Methylation of Cellular Retinoic Acid-Binding Proteins in Cervical Cancer

    PubMed Central

    Arellano-Ortiz, Ana L.; Salcedo-Vargas, Mauricio; Vargas-Requena, Claudia L.; López-Díaz, José A.; De la Mora-Covarrubias, Antonio; Silva-Espinoza, Juan C.; Jiménez-Vega, Florinda

    2016-01-01

    This study determined the methylation status of cellular retinoic acid-binding protein (CRABP) gene promoters and associated them with demographic characteristics, habits, and the presence of human papilloma virus (HPV) in patients with cervical cancer (CC), low and high squamous intraepithelial lesions, and no intraepithelial lesion. Women (n = 158) were selected from the Colposcopy Clinic of Sanitary Jurisdiction II in Ciudad Juarez, Chihuahua, Mexico. Demographic characteristics and habit information were collected. Cervical biopsy and endocervical scraping were used to determine methylation in promoter regions by methylation-specific polymerase chain reaction technique. We found hemi-methylation patterns in the promoter regions of CRABP1 and CRABP2; there was 28.5% hemi-methylation in CRABP1 and 7.0% in that of CRABP2. Methylation in CRABP1 was associated with age (≥35 years, P = 0.002), family history of cancer (P = 0.032), the presence of HPV-16 (P = 0.013), and no alcohol intake (P = 0.035). These epigenetic changes could be involved in the CC process, and CRABP1 has the potential to be a predictive molecular marker of retinoid therapy response. PMID:27867303

  20. A novel methyltransferase from the intracellular pathogen Plasmodiophora brassicae methylates salicylic acid.

    PubMed

    Ludwig-Müller, Jutta; Jülke, Sabine; Geiß, Kathleen; Richter, Franziska; Mithöfer, Axel; Šola, Ivana; Rusak, Gordana; Keenan, Sandi; Bulman, Simon

    2015-05-01

    The obligate biotrophic pathogen Plasmodiophora brassicae causes clubroot disease in Arabidopsis thaliana, which is characterized by large root galls. Salicylic acid (SA) production is a defence response in plants, and its methyl ester is involved in systemic signalling. Plasmodiophora brassicae seems to suppress plant defence reactions, but information on how this is achieved is scarce. Here, we profile the changes in SA metabolism during Arabidopsis clubroot disease. The accumulation of SA and the emission of methylated SA (methyl salicylate, MeSA) were observed in P. brassicae-infected Arabidopsis 28 days after inoculation. There is evidence that MeSA is transported from infected roots to the upper plant. Analysis of the mutant Atbsmt1, deficient in the methylation of SA, indicated that the Arabidopsis SA methyltransferase was not responsible for alterations in clubroot symptoms. We found that P. brassicae possesses a methyltransferase (PbBSMT) with homology to plant methyltransferases. The PbBSMT gene is maximally transcribed when SA production is highest. By heterologous expression and enzymatic analyses, we showed that PbBSMT can methylate SA, benzoic and anthranilic acids.

  1. Experimental and Computational Study on the Molecular Energetics of 2-Pyrrolecarboxylic Acid and 1-Methyl-2-pyrrolecarboxylic Acid

    NASA Astrophysics Data System (ADS)

    Santos, Ana Filipa L. O. M.; Silva, Manuel A. V. Ribeiro Da

    2009-08-01

    This paper reports a combined thermochemical experimental and computational study of 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid. Static bomb combustion calorimetry and Knudsen mass-loss effusion technique were used to determine the standard (p° = 0.1 MPa) molar enthalpies of combustion, ΔcHm°, and sublimation, ΔcrgHm°, respectively, from which the standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, were derived. The values obtained were -(286.3 ± 1.7) and -(291.6 ± 1.7) kJ·mol for 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid, respectively. For comparison purposes, the gas-phase enthalpies of formation of these two compounds were estimated by G3(MP2)//B3LYP and MP2 approaches, using a set of gas-phase working reactions; the results are in excellent agreement with experimental data. G3(MP2)//B3LYP computations were also extended to the calculation of N-H bond dissociation enthalpies, gas-phase acidities and basicities, proton and electron affinities and adiabatic ionization enthalpies. Moreover, the results are also discussed in terms of the energetic effects of the addition of a carboxylic and of a methyl groups to the pyrrole ring and compared with structurally similar compounds.

  2. Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation

    PubMed Central

    2014-01-01

    Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)+ or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400 h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage. PMID:25328502

  3. Structures of polynuclear complexes of palladium(II) and platinum(II) formed by slow hydrolysis in acidic aqueous solution.

    PubMed

    Torapava, Natallia; Elding, Lars I; Mändar, Hugo; Roosalu, Kaspar; Persson, Ingmar

    2013-06-07

    The aqua ions of palladium(II) and platinum(II) undergo extremely slow hydrolysis in strongly acidic aqueous solution, resulting in polynuclear complexes. The size and structures of these species have been determined by EXAFS and small angle X-ray scattering, SAXS. For palladium(II), the EXAFS data show that the Pd-O and Pd···Pd distances are identical to those of crystalline palladium(II) oxide, but the intensities of the Pd···Pd distances in the Fourier transform at 3.04 and 3.42 Å are significantly lower compared to those of crystalline PdO. Furthermore, no Pd···Pd distances beyond 4 Å are observed. These observations strongly indicate that the polynuclear palladium(II) complexes are oxido- and hydroxido-bridged species with the same core structure as solid palladium(II) oxide. Based on the number of Pd···Pd distances, as derived from the EXAFS data, their size can be estimated to be approximately two unit cells, or ca. 1.0 nm(3). For platinum(II), EXAFS data of the polynuclear species formed in the slow hydrolysis process show Pt-O and Pt···Pt distances identical to those of amorphous platinum(II) oxide, precipitating from the solution studied. The Pt···Pt distances are somewhat different from those reported for crystalline platinum(II) oxide. The polynuclear platinum(II) complexes have a similar structure to the palladium ones, but they are somewhat larger, with an estimated diameter of 1.5-3.0 nm. It has not been possible to precipitate any of these species by ultracentrifugation. They are detectable by SAXS, indicating diameters between 0.7 and 2 nm, in excellent agreement with the EXAFS observations. The number of oxido- relative to hydroxido bridges will increase with increasing size of the complex. The charge of the complexes will remain about the same, +4, at growth, with approximate formulas [Pd10O4(OH)8(H2O)12](4+) and [Pt14O8(OH)8(H2O)12](4+) for complexes with a size of 2 and 3 unit cells of the corresponding solid metal oxide

  4. Poly(acrylic acid) nanogel as a substrate for cellulase immobilization for hydrolysis of cellulose.

    PubMed

    Ahmed, Ibrahim Nasser; Chang, Ray; Tsai, Wei-Bor

    2017-04-01

    Cellulase was adsorbed onto poly(acrylic acid), PAA, nanogel, that was fabricated via inverse-phase microemulsion polymerization. The PAA nanogel was around 150nm in diameter and enriched with carboxyl groups. The surface charge of PAA nanogel depended on the pHs of the environment and affected the adsorption of cellulase. The temperature stability of the immobilized cellulase was greatly enhanced in comparison to the free enzyme, especially at high temperature. At 80°C, the immobilized cellulase remained ∼75% of hydrolytic activity, in comparison to ∼55% for the free cellulase. Furthermore, the immobilized cellulase was more active than the free enzyme in acidic buffers. The immobilized cellulase could be recovered via centrifugation and can be used repeatedly, although the recovery ratio needs further improvement. In conclusion, PAA nanogel has the potential in the application of enzyme immobilization for biochemical processes.

  5. Antioxidant activities of fucoidan degraded by gamma irradiation and acidic hydrolysis

    NASA Astrophysics Data System (ADS)

    Lim, Sangyong; Choi, Jong-il; Park, Hyun

    2015-04-01

    Low molecular weight fucoidan, prepared by radical degradation using gamma ray was investigated for its antioxidant activities with different assay methods. As the molecular weight of fucoidan decreased with a higher absorbed dose, ferric-reducing antioxidant power values increased, but β-carotene bleaching inhibition did not change significantly. The antioxidant activity of acid-degraded fucoidan was also examined to investigate the effect of different degradation methods. At the same molecular weight, fucoidan degraded by gamma irradiation showed higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity than that observed with the acidic method. This result reveals that in addition to molecular weight, the degradation method affects the antioxidant activity of fucoidan.

  6. Production of xylooligosaccharides by microwave-induced, organic acid-catalyzed hydrolysis of different xylan-type hemicelluloses: Optimization by response surface methodology.

    PubMed

    Lin, Qixuan; Li, Huiling; Ren, Junli; Deng, Aojie; Li, Weiying; Liu, Chuanfu; Sun, Runcang

    2017-02-10

    A feasible approach to produce xylooligosaccharides (XOS) using organic acids as catalysts by microwave-induced hydrolysis of different hemicelluloses was developed. The effects of different acids (oxalic acid, maleic acid, citric acid and sulfuric acid), acid concentration, reaction temperature and reaction time on the hemicelluloses hydrolysis were investigated. Results demonstrated that organic acid was more beneficial to the XOS production than the conventional sulfuric acid. Higher acid concentration, higher reaction temperature and longer reaction time accelerated the further depolymerization of XOS to form monosaccharide. Response surface methodology was employed to optimize the reaction conditions (temperature and time) for the production of XOS from beechwood xylan (BX), corncob hemicelluloses (CH) and recovered hemicelluloses from the industrial waste liquor of dissolving pulp (RH), respectively. The predicted highest XOS yields were achieved to 39.31% (126.54°C-7.95min), 27.29% (120.00°C-0min), 30.32% (122.63°C-15.85min), respectively, being close to the experimental value (39.42%, 27.46% and 30.89%) from BX, CH and RH, indicating the fitted models of XOS yield were in good agreement with the experimental results.

  7. Thermochemistry of C-O, (CO)-O, and (CO)-C bond breaking in fatty acid methyl esters

    SciTech Connect

    Osmont, Antoine; Yahyaoui, Mohammed; Catoire, Laurent; Goekalp, Iskender; Swihart, Mark T.

    2008-10-15

    Density functional theory quantum chemical calculations corrected with empirical atomic increments have been used to examine C-O, (CO)-O, and (CO)-C bond scission enthalpies in gas-phase fatty acid methyl esters (FAMEs) present in biodiesel derived from rapeseed oil methyl ester and soybean oil methyl ester. Mechanistic information, currently not available elsewhere for these large species, is obtained based on thermochemical considerations and compared to thermochemical considerations reported for methyl butanoate, a small methyl ester sometimes used as a model for FAMEs. These results are compared to previously reported C-C and C-H bond scissions in these FAMEs, derived using this same protocol. (author)

  8. Efficient production of the Nylon 12 monomer ω-aminododecanoic acid methyl ester from renewable dodecanoic acid methyl ester with engineered Escherichia coli.

    PubMed

    Ladkau, Nadine; Assmann, Miriam; Schrewe, Manfred; Julsing, Mattijs K; Schmid, Andreas; Bühler, Bruno

    2016-07-01

    The expansion of microbial substrate and product scopes will be an important brick promoting future bioeconomy. In this study, an orthogonal pathway running in parallel to native metabolism and converting renewable dodecanoic acid methyl ester (DAME) via terminal alcohol and aldehyde to 12-aminododecanoic acid methyl ester (ADAME), a building block for the high-performance polymer Nylon 12, was engineered in Escherichia coli and optimized regarding substrate uptake, substrate requirements, host strain choice, flux, and product yield. Efficient DAME uptake was achieved by means of the hydrophobic outer membrane porin AlkL increasing maximum oxygenation and transamination activities 8.3 and 7.6-fold, respectively. An optimized coupling to the pyruvate node via a heterologous alanine dehydrogenase enabled efficient intracellular L-alanine supply, a prerequisite for self-sufficient whole-cell transaminase catalysis. Finally, the introduction of a respiratory chain-linked alcohol dehydrogenase enabled an increase in pathway flux, the minimization of undesired overoxidation to the respective carboxylic acid, and thus the efficient formation of ADAME as main product. The completely synthetic orthogonal pathway presented in this study sets the stage for Nylon 12 production from renewables. Its effective operation achieved via fine tuning the connectivity to native cell functionalities emphasizes the potential of this concept to expand microbial substrate and product scopes.

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

    PubMed

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

    2016-05-01

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

  10. Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

    PubMed

    Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

    2016-03-01

    A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples.

  11. Assessment of bioavailable organic phosphorus in tropical forest soils by organic acid extraction and phosphatase hydrolysis.

    PubMed

    Darch, Tegan; Blackwell, Martin S A; Chadwick, David; Haygarth, Philip M; Hawkins, Jane M B; Turner, Benjamin L

    2016-12-15

    Soil organic phosphorus contributes to the nutrition of tropical trees, but is not accounted for in standard soil phosphorus tests. Plants and microbes can release organic anions to solubilize organic phosphorus from soil surfaces, and synthesize phosphatases to release inorganic phosphate from the solubilized compounds. We developed a procedure to estimate bioavailable organic phosphorus in tropical forest soils by simulating the secretion processes of organic acids and phosphatases. Five lowland tropical forest soils with contrasting properties (pH 4.4-6.1, total P 86-429 mg P kg(- 1)) were extracted with 2 mM citric acid (i.e., 10 μmol g(- 1), approximating rhizosphere concentrations) adjusted to soil pH in a 4:1 solution to soil ratio for 1 h. Three phosphatase enzymes were then added to the soil extract to determine the forms of hydrolysable organic phosphorus. Total phosphorus extracted by the procedure ranged between 3.22 and 8.06 mg P kg(- 1) (mean 5.55 ± 0.42 mg P kg(- 1)), of which on average three quarters was unreactive phosphorus (i.e., organic phosphorus plus inorganic polyphosphate). Of the enzyme-hydrolysable unreactive phosphorus, 28% was simple phosphomonoesters hydrolyzed by phosphomonoesterase from bovine intestinal mucosa, a further 18% was phosphodiesters hydrolyzed by a combination of nuclease from Penicillium citrinum and phosphomonoesterase, and the remaining 51% was hydrolyzed by a broad-spectrum phytase from wheat. We conclude that soil organic phosphorus can be solubilized and hydrolyzed by a combination of organic acids and phosphatase enzymes in lowland tropical forest soils, indicating that this pathway could make a significant contribution to biological phosphorus acquisition in tropical forests. Furthermore, we have developed a method that can be used to assess the bioavailability of this soil organic phosphorus.

  12. Enzymatic hydrolysis of cellulose pretreated with zinc chloride and hydrochloric acid

    SciTech Connect

    Chen, L.F.; Gong, C.S.

    1982-01-01

    Microcrystalline cellulose, Avicel, was dissolved in a concentrated solution of ZnCl/sub 2/ and 0.5% hydrochloric acid followed by heating at 145/sup 0/C for 6 min. after cooling, cellulose in its amorphous form was precipitated by the addition of acetone. The resulting cellulose was hydrolyzed by cellulase derived from Trichoderma viride. At concentrations of 20% cellulose and 1% cellulase, cellulose was hydrolyzed completely for form a solution of 19% glucose and 1% cellobiose within 72 h of incubation. 1 figure, 5 tables.

  13. Difference analysis of the enzymatic hydrolysis performance of acid-catalyzed steam-exploded corn stover before and after washing with water.

    PubMed

    Zhu, Junjun; Shi, Linli; Zhang, Lingling; Xu, Yong; Yong, Qiang; Ouyang, Jia; Yu, Shiyuan

    2016-10-01

    The difference in the enzymatic hydrolysis yield of acid-catalyzed steam-exploded corn stover (ASC) before and after washing with water reached approximately 15 % under the same conditions. The reasons for the difference in the yield between ASC and washed ASC (wASC) were determined through the analysis of the composition of ASC prehydrolyzate and sugar concentration of enzymatic hydrolyzate. Salts produced by neutralization (CaSO4, Na2SO4, K2SO4, and (NH4)2SO4), sugars (polysaccharides, oligosaccharides, and monosaccharides), sugar-degradation products (weak acids and furans), and lignin-degradation products (ethyl acetate extracts and nine main lignin-degradation products) were back-added to wASC. Results showed that these products, except furans, exerted negative effect on enzymatic hydrolysis. According to the characteristics of acid-catalyzed steam explosion pretreatment, the five sugar-degradation products' mixture and salts [Na2SO4, (NH4)2SO4] showed minimal negative inhibition effect on enzymatic hydrolysis. By contrast, furans demonstrated a promotion effect. Moreover, soluble sugars, such as 13 g/L xylose (decreased by 6.38 %), 5 g/L cellobiose (5.36 %), 10 g/L glucose (3.67 %), as well as lignin-degradation products, and ethyl acetate extracts (4.87 %), exhibited evident inhibition effect on enzymatic hydrolysis. Therefore, removal of soluble sugars and lignin-degradation products could effectively promote the enzymatic hydrolysis performance.

  14. Comparative study of the fatty acid composition of sponges of the genus Ircinia. Identification of the new 23-methyl-5,9-tetracosadienoic acid.

    PubMed

    Carballeira, N M; Shalabi, F; Cruz, C; Rodriguez, J; Rodriguez, E

    1991-01-01

    1. The phospholipid fatty acid compositions of the sponges Ircinia strobilina, Ircinia felix, Ircinia campana, Ircinia sp., Spongia tubulifera and Dysidea etherea were studied, revealing the presence, besides other common fatty acids, of considerable amounts (2-5%) of the novel 23-methyl-5,9-tetracosadienoic acid (1). 2. The demospongic acids 5,9-tetracosadienoic acid, 23-methyl-5,9-tetracosadienoic acid (1), and 5,9-pentacosadienoic acid, were particularly abundant in sponges of the genus Ircinia, in contrast to the most common 5,9-hexacosadienoic acid found in other species. These findings are discussed in terms of the taxonomy of the Dictyoceratida. 3. The complete characterization of the novel phospholipid fatty acid 23-methyl-5,9-tetracosadienoic acid (1) is presented.

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

    PubMed

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

    2016-01-01

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

  16. High yield production of sugars from deproteinated palm kernel cake under microwave irradiation via dilute sulfuric acid hydrolysis.

    PubMed

    Fan, Suet-Pin; Jiang, Li-Qun; Chia, Chin-Hua; Fang, Zhen; Zakaria, Sarani; Chee, Kah-Leong

    2014-02-01

    Recent years, great interest has been devoted to the conversion of biomass-derived carbohydrate into sugars, such as glucose, mannose and fructose. These are important versatile intermediate products that are easily processed into high value-added biofuels. In this work, microwave-assisted dilute sulfuric acid hydrolysis of deproteinated palm kernel cake (DPKC) was systematically studied using Response Surface Methodology. The highest mannose yield (92.11%) was achieved at the optimized condition of 148°C, 0.75N H2SO4, 10min 31s and substrate to solvent (SS) ratio (w/v) of 1:49.69. Besides that, total fermentable sugars yield (77.11%), was obtained at 170°C, 0.181N H2SO4, 6min 6s and SS ratio (w/v) of 1:40. Ridge analysis was employed to further verify the optimum conditions. Thus, this work provides fundamental data of the practical use of DPKC as low cost, high yield and environmental-friendly material for the production of mannose and other sugars.

  17. Enhanced enzymatic hydrolysis and acetone-butanol-ethanol fermentation of sugarcane bagasse by combined diluted acid with oxidate ammonolysis pretreatment.

    PubMed

    Li, Hailong; Xiong, Lian; Chen, Xuefang; Wang, Can; Qi, Gaoxiang; Huang, Chao; Luo, Mutan; Chen, Xinde

    2017-03-01

    This study aims to propose a biorefinery pretreatment technology for the bioconversion of sugarcane bagasse (SB) into biofuels and N-fertilizers. Performance of diluted acid (DA), aqueous ammonia (AA), oxidate ammonolysis (OA) and the combined DA with AA or OA were compared in SB pretreatment by enzymatic hydrolysis, structural characterization and acetone-butanol-ethanol (ABE) fermentation. Results indicated that DA-OA pretreatment improves the digestibility of SB by sufficiently hydrolyzing hemicellulose into fermentable monosaccharides and oxidating lignin into soluble N-fertilizer with high nitrogen content (11.25%) and low C/N ratio (3.39). The enzymatic hydrolysates from DA-OA pretreated SB mainly composed of glucose was more suitable for the production of ABE solvents than the enzymatic hydrolysates from OA pretreated SB containing high ratio of xylose. The fermentation of enzymatic hydrolysates from DA-OA pretreated SB produced 12.12g/L ABE in 120h. These results suggested that SB could be utilized efficient, economic, and environmental by DA-OA pretreatment.

  18. Evolutionary Importance of the Intramolecular Pathways of Hydrolysis of Phosphate Ester Mixed Anhydrides with Amino Acids and Peptides

    PubMed Central

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-01-01

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide–phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation. PMID:25501391

  19. Evolutionary Importance of the Intramolecular Pathways of Hydrolysis of Phosphate Ester Mixed Anhydrides with Amino Acids and Peptides

    NASA Astrophysics Data System (ADS)

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-12-01

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide-phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation.

  20. Evolutionary importance of the intramolecular pathways of hydrolysis of phosphate ester mixed anhydrides with amino acids and peptides.

    PubMed

    Liu, Ziwei; Beaufils, Damien; Rossi, Jean-Christophe; Pascal, Robert

    2014-12-11

    Aminoacyl adenylates (aa-AMPs) constitute essential intermediates of protein biosynthesis. Their polymerization in aqueous solution has often been claimed as a potential route to abiotic peptides in spite of a highly efficient CO2-promoted pathway of hydrolysis. Here we investigate the efficiency and relevance of this frequently overlooked pathway from model amino acid phosphate mixed anhydrides including aa-AMPs. Its predominance was demonstrated at CO2 concentrations matching that of physiological fluids or that of the present-day ocean, making a direct polymerization pathway unlikely. By contrast, the occurrence of the CO2-promoted pathway was observed to increase the efficiency of peptide bond formation owing to the high reactivity of the N-carboxyanhydride (NCA) intermediate. Even considering CO2 concentrations in early Earth liquid environments equivalent to present levels, mixed anhydrides would have polymerized predominantly through NCAs. The issue of a potential involvement of NCAs as biochemical metabolites could even be raised. The formation of peptide-phosphate mixed anhydrides from 5(4H)-oxazolones (transiently formed through prebiotically relevant peptide activation pathways) was also observed as well as the occurrence of the reverse cyclization process in the reactions of these mixed anhydrides. These processes constitute the core of a reaction network that could potentially have evolved towards the emergence of translation.

  1. Relationship between stimulated phosphatidic acid production and inositol lipid hydrolysis in intestinal longitudinal smooth muscle from guinea pig.

    PubMed

    Mallows, R S; Bolton, T B

    1987-06-15

    Accumulation of [32P]phosphatidic acid (PA) and total [3H]inositol phosphates (IPs) was measured in the longitudinal smooth-muscle layer from guinea-pig small intestine. Stimulation with carbachol, histamine and substance P produced increases in accumulation of both [3H]IPs and [32P]PA over the same concentration range. The increase in [32P]PA accumulation in response to carbachol (1 microM-0.1 mM) was inhibited in the presence of atropine (0.5 microM). Buffering the external free [Ca2+] to 10 nM did not prevent the carbachol-stimulated increase in [32P]PA accumulation. Carbachol and Ca2+ appear to act synergistically to increase accumulation of [32P]PA. In contrast, although incubation with noradrenaline also increased accumulation of [3H]IPs, no increase in accumulation of [32P]PA could be detected. These results suggest that an increase in formation of IPs is not necessarily accompanied by an increase in PA formation, and imply the existence of receptor-modulated pathways regulating PA concentrations other than by phospholipase-C-catalysed inositol phospholipid hydrolysis.

  2. Acetylsalicylic acid, aging and coronary artery disease are associated with ABCA1 DNA methylation in men

    PubMed Central

    2014-01-01

    Background Previous studies have suggested that DNA methylation contributes to coronary artery disease (CAD) risk variability. DNA hypermethylation at the ATP-binding cassette transporter A1 (ABCA1) gene, an important modulator of high-density lipoprotein cholesterol and reverse cholesterol transport, has been previously associated with plasma lipid levels, aging and CAD, but the association with CAD has yet to be replicated. Results ABCA1 DNA methylation levels were measured in leucocytes of 88 men using bis-pyrosequencing. We first showed that DNA methylation at the ABCA1 gene promoter locus is associated with aging and CAD occurrence in men (P < 0.05). The latter association is stronger among older men with CAD (≥61 years old; n = 19), who showed at least 4.7% higher ABCA1 DNA methylation levels as compared to younger men with CAD (<61 years old; n = 19) or men without CAD (n = 50; P < 0.001). Higher ABCA1 DNA methylation levels in older men were also associated with higher total cholesterol (r = 0.34, P = 0.03), low-density lipoprotein cholesterol (r = 0.32, P = 0.04) and triglyceride levels (r = 0.26, P = 0.09). Furthermore, we showed that acetylsalicylic acid therapy is associated with 3.6% lower ABCA1 DNA methylation levels (P = 0.006), independent of aging and CAD status of patients. Conclusions This study provides new evidence that the ABCA1 epigenetic profile is associated with CAD and aging, and highlights that epigenetic modifications might be a significant molecular mechanism involved in the pathophysiological processes associated with CAD. Acetylsalicylic acid treatment for CAD prevention might involve epigenetic mechanisms. PMID:25093045

  3. 40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3,3â²-methyl-enebis...

  4. 40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid, 3,3â²-methyl-enebis...

  5. 40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid, 3,3â²-methyl-enebis...

  6. 40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid, 3,3â²-methyl-enebis...

  7. 40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3,3â²-methyl-enebis...

  8. Coordination chemistry and hydrolysis of Fe(III) in a peat humic acid studied by X-ray absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Karlsson, Torbjörn; Persson, Per

    2010-01-01

    The speciation of iron (Fe) in soils, sediments and surface waters is highly dependent on chemical interactions with natural organic matter (NOM). However, the molecular structure and hydrolysis of the Fe species formed in association with NOM is still poorly described. In this study extended X-ray absorption fine structure (EXAFS) spectroscopy was used to determine the coordination chemistry and hydrolysis of Fe(III) in solution of a peat humic acid (5010-49,200 μg Fe g -1 dry weight, pH 3.0-7.2). Data were analyzed by both conventional EXAFS data fitting and by wavelet transforms in order to facilitate the identification of the nature of backscattering atoms. Our results show that Fe occurs predominantly in the oxidized form as ferric ions and that the speciation varies with pH and Fe concentration. At low Fe concentrations (5010-9920 μg g -1; pH 3.0-7.2) mononuclear Fe(III)-NOM complexes completely dominates the speciation. The determined bond distances for the Fe(III)-NOM complexes are similar to distances obtained for Fe(III) complexed by desferrioxamine B and oxalate indicating the formation of a five-membered chelate ring structure. At higher Fe concentrations (49,200 μg g -1; pH 4.2-6.9) we detect a mixture of mononuclear Fe(III)-NOM complexes and polymeric Fe(III) (hydr)oxides with an increasing amount of Fe(III) (hydr)oxides at higher pH. However, even at pH 6.9 and a Fe concentration of 49,200 μg g -1 our data indicates that a substantial amount of the total Fe (>50%) is in the form of organic complexes. Thus, in environments with significant amounts of organic matter organic Fe complexes will be of great importance for the geochemistry of Fe. Furthermore, the formation of five-membered chelate ring structures is in line with the strong complexation and limited hydrolytic polymerization of Fe(III) in our samples and also agrees with EXAFS derived structures of Fe(III) in organic soils.

  9. In Candida parapsilosis the ATC1 Gene Encodes for an Acid Trehalase Involved in Trehalose Hydrolysis, Stress Resistance and Virulence

    PubMed Central

    Sánchez-Fresneda, Ruth; Martínez-Esparza, María; Maicas, Sergi; Argüelles, Juan-Carlos; Valentín, Eulogio

    2014-01-01

    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. PMID:24922533

  10. Accumulation of methyl-deficient rat liver messenger ribonucleic acid on ethionine administration

    SciTech Connect

    Goswami, B.B.; Sharma, O.K.

    1980-01-01

    Highly purified poly(adenylic acid)-containing RNA isolated from livers of rats fed 0.25% DL-etionine in the diet for 7 days accepted methyl groups from S-adenosyl(methyl-/sup 3/H)methionine, when incubated in vitro with mRNA methyltransferases from vaccinia virus or Ehrlich ascites cells, whereas RNA from control rats had no such activity. Nuclease digestion followed by chromatographic analyses of mRNA methylated in vitro revealed that the methyl groups were incorporated at the 5' end into cap 1 structures (m/sup 7/GpppNmp...) by the viral enzyme, whereas both cap 0 (m/sup 7/GpppNp...) and cap 1 (m/sup 7/Gpppm/sup 6/Am...) structures were formed by the Ehrlich ascites cell enzymes. the methyl-deficient mRNA isolated from the liver of ethionine-fed rats differed in its translational properties from mRNA isolated from control animals in an in vitro protein synthesizing system from wheat germ.

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    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 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 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).

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

    PubMed Central

    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 (3B1), which may be accessed by near-UV solar excitation of SO2 to its excited 1B1 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

  14. Dissociative electron-ion recombination of the interstellar species protonated glycolaldehyde, acetic acid, and methyl formate.

    PubMed

    Lawson, Patrick A; Osborne, David S; Adams, Nigel G

    2012-03-22

    Recently, methyl formate, glycolaldehyde, and acetic acid have been detected in the Interstellar Medium, ISM. The rate constants, α(e), for dissociative electron-ion recombination of protonated gycolaldehyde, (HOCH(2)CHO)H(+), and protonated methyl formate, (HCOOCH(3))H(+), have been determined at 300 K in a variable temperature flowing afterglow using a Langmuir probe to obtain the electron density. The recombination rate constants at 300 K are 3.2 × 10(-7) cm(3) s(-1) for protonated methyl formate and 7.5 × 10(-7) cm(3) s(-1) for protonated glycolaldehyde. The recombination rate constant of protonated acetic acid could not be directly measured, but it appears to have a rate constant, α(e), on the 10(-7) cm(3) s(-1) scale. Several high- and low-temperature measurements for protonated methyl formate were made. In addition, an α(e) measurement at 220 K for protonated glycolaldehyde was performed. The astrochemical implications of the rates of recombination, α(e), and protonation routes are discussed.

  15. Theoretical study of the regioselectivity of the interaction of 3-methyl-4-pyrimidone and 1-methyl-2-pyrimidone with Lewis acids.

    PubMed

    Kasende, Okuma Emile; Muya, Jules Tshishimbi; Broeckaert, Lies; Maes, Guido; Geerlings, Paul

    2012-08-23

    A density functional theory (DFT) study is performed to determine the stability of the complexes formed between either the N or O site of 3-methyl-4-pyrimidone and 1-methyl-2-pyrimidone molecules and different ligands. The studied ligands are boron and alkali Lewis acids, namely, B(CH(3))(3), HB(CH(3))(2), H(2)B(CH(3)), BH(3), H(2)BF, HBF(2), BF(3), Li(+), Na(+), and K(+). The acids are divided into two groups according to their hardness. The reactivity predictions, according to the molecular electrostatic potential (MEP) map and the natural bond orbital (NBO) analysis, are in agreement with the calculated relative stabilities. Our findings reveal a strong regioselectivity with borane and its derivatives preferring the nitrogen site in both pyrimidone isomers, while a preference for oxygen is observed for the alkali acids in the 3-methyl-4-pyrimidone molecule. The complexation of 1-methyl-2-pyrimidone with these hard alkali acids does not show any discrimination between the two sites due to the presence of a continuous delocalized density region between the nitrogen and the oxygen atoms. The preference of boron Lewis acids toward the N site is due to the stronger B-N bond as compared to the B-O bond. The influence of fluorine or methyl substitution on the boron atom is discussed through natural orbital analysis (NBO) concentrating on the overlap of the boron empty p-orbital with the F lone pairs and methyl hyperconjugation, respectively. The electrophilicity of the boron acids gives a good overall picture of the interaction capabilities with the Lewis base.

  16. Surface lignin change pertaining to the integrated process of dilute acid pre-extraction and mechanical refining of poplar wood chips and its impact on enzymatic hydrolysis.

    PubMed

    Liu, Wei; Chen, Wei; Hou, Qingxi; Zhang, Jinping; Wang, Bing

    2017-03-01

    Dilute acid pre-extraction enhanced the mechanically refined poplar pulp substrates' enzymatic hydrolysis efficiency obviously. The results showed that the surface lignin distribution was changed significantly in residual wood chips and pulp substrates, and the surface lignin distribution showed important impact on the following enzymatic hydrolysis. Acid pre-extraction can lead to a redistribution of lignin in fiber cell walls, i.e., the lignin was degraded and migrated to fiber surface in the form of re-deposited lignin and pseudo-lignin. However, higher pre-extraction intensity was not desired due to the formation of redeposited lignin and pseudo-lignin. This study will help to reach a deeper understanding on the lignin distribution in the view of molecular and ultrastructure, and promote the development of a cost-efficient pretreatment strategy for biomass processing.

  17. Methylation of ethylene over Lewis-acid catalysts

    SciTech Connect

    Sekhar, M.V.C.

    1994-12-31

    As a major constituent of natural gas, methane is abundant and is a relatively inexpensive feedstock for a variety of chemicals. The use of methane as a fuel is straightforward. Consequently, over the years, considerable research has been conducted to develop technologies for its efficient utilization. Work on adsorbents for storing natural gas on-board automotive vehicles promises to expand its use considerably. Conversely, the use of methane as a chemical feedstock requires either the energy- and capital-intensive production of intermediate synthesis gas or its thermal cracking to a range of hydrocarbons. In recent years there has been a great deal of interest in processes that convert methane directly to olefins, methanol and other functionalized methane derivatives. Among the various conversion processes currently under development, the Oxidative Coupling (OC) route is the most promising. With increased attention being given to OC process, engineers have also begun outlining the corresponding reaction engineering aspects. The OC of methane rich natural gas yields a dilute olefin stream. At 25% hydrocarbon conversion, the ethylene in the dry reactor effluent is about 5%, with some propylene and other hydrocarbons. Because of the presence of large amounts of unconverted methane in the effluent, product separation is one of the main points of optimization in the existing oxidative coupling technology. Consequently, a processing scheme which does not require further separation of the product of the OC rector would be of considerable advantage. Reactions between methane and ethylene using a number of solid acids have also been reported by a number of authors in the past. However, some of these experiments were conducted at temperatures higher than ambient. In this paper we report some of the results obtained at ambient temperature as part of a screening program for developing catalyst systems for co-reacting methane with ethylene to produce higher hydrocarbons.

  18. [Determination of 2-methyl-3-nitrobenzoic acid through pretreatment with diazomethane by gas chromatography].

    PubMed

    Xue, Ke-She; Nan, Zhi-Xiang

    2002-09-01

    A method for the quantitative determination of 2-methyl-3-nitrobenzoic acid by gas chromatography is described. 2-Methyl-3-nitrobenzoic acid was esterified by pretreatment with diazomethane prior to analysis. A CP-Sil-43CB capillary column(25 m x 0.32 mm i.d. x 0.2 microm), a flame ionization detector and the area normalization method were used. The average recovery was 99.81%. The RSD was 0.08% and the detection limit was 3 x 10(-11) g. The results showed that the method is practical and reliable. It was realized that the higher purity and higher boiler matter was analyzed by gas chromatography. The method can be used to monitor the purity of this type of materials. analysis of research and production. It can be used in the development of new products and in the process.

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

    SciTech Connect

    Parente, J.E.; Risley, J.M.; Van Etten, R.L.

    1984-12-26

    The /sup 18/O isotope-induced shifts in /sup 13/C and /sup 31/P 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 /sup 18/O-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, (..cap alpha..-/sup 13/C,ester-/sup 18/O)benzyl phosphate and (ester-/sup 18/O)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 75/sup 0/C 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 < pH < 2.0, there is a mixture of C-O and P-O bond scission, the latter progressively predominating as the pH is raised; at pH greater than or equal to 2.0, the hydrolysis proceeds with exclusive P-O bond scission. (S)-(+)-(..cap alpha..-/sup 2/H)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.

  20. Excessive S-Adenosyl-L-Methionine-Dependent Methylation Increases Levels of Methanol, Formaldehyde and Formic Acid in Rat Brain Striatal Homogenates: Possible role in S-adenosyl-L-methionine-induced Parkinson’s disease-like disorders

    PubMed Central

    Lee, Eun-Sook; Chen, Hongtao; Hardman, Chadwick; Simm, Anthony; Charlton, Clivel

    2009-01-01

    Aims Excessive methylation may be a precipitating factor for Parkinson’s disease (PD) since S-adenosylmethionine (SAM), the endogenous methyl donor, induces PD-like changes when injected into the rat brain. The hydrolysis of the methyl ester bond of the methylated proteins produces methanol. Since methanol is oxidized into formaldehyde, and formaldehyde into formic acid in the body, we investigated the effects of SAM on the production of methanol, formaldehyde and formic acid in rat brain striatal homogenates and the toxicity of these products in PC12 cells. Main methods radio-enzymatic and colorimetric assays, cell viability, Western blot. Key findings SAM increased the formation of methanol, formaldehyde and formic acid in a concentration and time-dependent manner. Concentrations of [3H-methyl]-SAM at 0.17, 0.33, 0.67 and 1.34 nM produced 3.8, 8.0, 18.3 and 34.4 fmol/mg protein/h of [3H] methanol in rat striatal homogenates, respectively. SAM also significantly generated formaldehyde and formic acid in striatal homogenates. Formaldehyde was the most toxic metabolite to differentiated PC12 pheochromocytoma cells in cell culture studies, indicating that formaldehyde formed endogenously may contribute to neuronal damage in excessive methylation conditions. Subtoxic concentration of formaldehyde decreased the expression of tyrosine hydroxylase, the limiting factor in dopamine synthesis. Formaldehyde was more toxic to catecholaminergic PC12 cells than C6 glioma cells, indicating that neurons are more vulnerable to formaldehyde than glia cells. Significance We suggest that excessive carboxylmethylation of proteins might be involved in the SAM-induced PD-like changes and in the aging process via the toxic effects of formaldehyde. PMID:18930743

  1. Measurement of pectin methylation in plant cell walls

    SciTech Connect

    McFeeters, R.F.; Armstrong, S.A.

    1984-01-01

    A procedure was developed to measure the degree of pectin methylation in small samples of isolated cell walls from nonlignified plant tissues or pectin solutions. Galacturonic acid was determined colorimetrically with the 3,5-dimethylphenol reagent. Methylation was measured by base hydrolysis of galacturonic acid methyl esters, followed by gas chromatographic determination of released methanol. Estimates of the precision of analysis of pectin and cell wall samples were made. The coefficient of variation for estimates of the pectin esterification in cell walls isolated from 10-g samples of cucumber tissue ranged from 7.7 to 13.2%.

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

    SciTech Connect

    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

  3. A new effective process for production of curdlan oligosaccharides based on alkali-neutralization treatment and acid hydrolysis of curdlan particles in water suspension.

    PubMed

    Li, Jing; Zhu, Li; Zheng, Zhi-Yong; Zhan, Xiao-Bei; Lin, Chi-Chung; Zong, Yu; Li, Wei-Jiang

    2013-10-01

    Biologically active β-1,3-oligosaccharides with rapidly growing biomedical applications are produced from hydrolysis of curdlan polysaccharide. The water-insoluble curdlan impedes its hydrolysis efficiency which is enhanced by our newly developed alkali-neutralization treatment process to increase the stability of curdlan suspension to more than 20 days, while the untreated control settled within 5 min. A putative double-layer structure model comprising of a compact core and a hydrated outer layer was proposed to describe the treated curdlan particles based on sedimentation and scanning electron microscopy observation. This model was verified by single- and two-step acid hydrolysis, indicative of the reduced susceptibility to hydrolysis when close to the compact core. Electrospray ionization-mass spectrometry, thin-layer chromatography analyses, and effective HPLC procedure led to the development of improved process to produce purified individual β-1,3-oligosaccharides with degrees of polymerization from 2 to 10 and potential for biomedical applications from curdlan hydrolyzate. Our new curdlan oligosaccharide production process offers an even better alternative to the previously published processes.

  4. Hydrolysis and volatile fatty acids accumulation of waste activated sludge enhanced by the combined use of nitrite and alkaline pH.

    PubMed

    Huang, Cheng; Liu, Congcong; Sun, Xiuyun; Sun, Yinglu; Li, Rui; Li, Jiansheng; Shen, Jinyou; Han, Weiqing; Liu, Xiaodong; Wang, Lianjun

    2015-12-01

    Volatile fatty acids (VFAs) production from anaerobic digestion of waste activated sludge (WAS) is often limited by the slow hydrolysis and/or poor substrate availability. Increased attention has been given to enhance the hydrolysis and acidification of WAS recently. This study presented an efficient and green strategy based on the combined use of nitrite pretreatment and alkaline pH to stimulate hydrolysis and VFA accumulation from WAS. Results showed that both proteins and polysaccharides increased in the presence of nitrite, indicating the enhancement of sludge solubilization and hydrolysis processes. Mechanism investigations showed that nitrite pretreatment could disintegrate the sludge particle and disperse extracellular polymeric substances (EPS). Then, anaerobic digestion tests demonstrated VFA production increased with nitrite treatment. The maximal VFA accumulation was achieved with 0.1 g N/L nitrite dosage and pH 10.0 at a sludge retention time (SRT) of 7 days, which was much higher VFA production in comparison with the blank, sole nitrite pretreatment, or sole pH 10. The potential analysis suggested that the combined nitrite pretreatment and alkaline pH is capable of enhancing WAS digestion with a great benefit for biological nutrient removal (BNR).

  5. Synthesis, Chemical and Enzymatic Hydrolysis, and Aqueous Solubility of Amino Acid Ester Prodrugs of 3-Carboranyl Thymidine Analogues for Boron Neutron Capture Therapy of Brain Tumors

    PubMed Central

    Hasabelnaby, Sherifa; Goudah, Ayman; Agarwal, Hitesh K.; Abd alla, Mosaad S. M.; Tjarks, Werner

    2012-01-01

    Various water-soluble L-valine-, L-glutamate-, and glycine ester prodrugs of two 3-Carboranyl Thymidine Analogues (3-CTAs), designated N5 and N5-2OH, were synthesized for Boron Neutron Capture Therapy (BNCT) of brain tumors since the water solubilities of the parental compounds proved to be insufficient in preclinical studies. The amino acid ester prodrugs were prepared and stored as hydrochloride salts. The water solubilities of these amino acid ester prodrugs, evaluated in phosphate buffered saline (PBS) at pH 5, pH 6 and pH 7.4, improved 48 to 6600 times compared with parental N5 and N5-2OH. The stability of the amino acid ester prodrugs was evaluated in PBS at pH 7.4, Bovine serum, and Bovine cerebrospinal fluid (CSF). The rate of the hydrolysis in all three incubation media depended primarily on the amino acid promoiety and, to a lesser extend, on the site of esterification at the deoxyribose portion of the 3-CTAs. In general, 3'-amino acid ester prodrugs were less sensitive to chemical and enzymatic hydrolysis than 5'-amino acid ester prodrugs and the stabilities of the latter decreased in the following order: 5'-valine > 5'-glutamate > 5'-glycine. The rate of the hydrolysis of the 5'-amino acid ester prodrugs in Bovine CSF was overall higher than in PBS and somewhat lower than in Bovine serum. Overall, 5'-glutamate ester prodrug of N5 and the 5'-glycine ester prodrugs of N5 and N5-2OH appeared to be the most promising candidates for preclinical BNCT studies. PMID:22889558

  6. 21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... produce fatty acid methyl esters, which then undergo conjugation to yield methyl esters of octadecadienoic... contain not less than 35 percent of other fatty acid esters composed of oleic acid, palmitic acid, stearic... the feed of growing and finishing swine as a source of fatty acids at levels not to exceed 0.6% in...

  7. 21 CFR 573.637 - Methyl esters of conjugated linoleic acid (cis-9, trans-11 and trans-10, cis-12-octadecadienoic...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... produce fatty acid methyl esters, which then undergo conjugation to yield methyl esters of octadecadienoic... contain not less than 35 percent of other fatty acid esters composed of oleic acid, palmitic acid, stearic... the feed of growing and finishing swine as a source of fatty acids at levels not to exceed 0.6% in...

  8. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-07

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  9. Observation of the side chain O-methylation of glutamic acid or aspartic acid containing model peptides by electrospray ionization-mass spectrometry.

    PubMed

    Atik, A Emin; Guray, Melda Z; Yalcin, Talat

    2017-03-15

    O-methylation of the side chains of glutamic acid (E) and aspartic acid (D) residues is generally observed modification when an acidified methanol/water (MeOH/dH2O) mixture is used as a solvent system during sample preparation for proteomic research. This chemical modification may result misidentification with endogenous protein methylation; therefore, a special care should be taken during sample handling prior to mass spectrometric analysis. In the current study, we systematically examined the extent of E/D methylation and C-terminus carboxyl group of synthetic model peptides in terms of different incubation temperatures, storage times, and added acid types as well as its percentages. To monitor these effects, C-terminus amidated and free acid forms of synthetic model peptides comprised of E or D residue(s) have been analyzed by electrospray ionization-mass spectrometry (ESI-MS). Additionally, LC-MS/MS experiments were performed to confirm the formation of methylated peptide product. The results showed that the rate of methylation was increased as the temperature increases along with prolong incubation times. Moreover, the extent of methylation was remarkably high when formic acid (FA) used as a protonation agent instead of acetic acid (AA). In addition, it was found that the degree of methylation was significantly decreased by lowering acid percentages in ESI solution. More than one acidic residue containing model peptides have been also used to explore the extent of multiple methylation reaction. Lastly, the ethanol (EtOH) and isopropanol (iPrOH) have been substituted separately with MeOH in sample preparation step to investigate the extent of esterification reaction under the same experimental conditions. However, in the positive perspective of view, this method can be used as a simple, rapid and cheap method for methylation of acidic residues under normal laboratory conditions.

  10. Complexation of NpO2+ with N-methyl-iminodiacetic Acid: in Comparison with Iminodiacetic and Dipicolinic Acids

    SciTech Connect

    Tian, Guoxin; Rao, Linfeng

    2010-10-01

    Complexation of Np(V) with N-methyl-iminodiacetic acid (MIDA) in 1 M NaClO{sub 4} solution was studied with multiple techniques including potentiometry, spectrophotometry, and microcalorimetry. The 1:2 complex, NpO{sub 2}(MIDA){sub 2}{sup 3-} was identified for the first time in aqueous solution. The correlation between its optical absorption properties and symmetry was discussed, in comparison with Np(V) complexes with two structurally related nitrilo-dicarboxylic acids, iminodiacetic acid (IDA) and dipicolinic acid (DPA). The order of the binding strength (DPA > MIDA > IDA) is explained by the difference in the structural and electronic properties of the ligands. In general, the nitrilo-dicarboxylates form stronger complexes with Np(V) than oxy-dicarboxylates due to a much more favorable enthalpy of complexation.

  11. A process economic approach to develop a dilute-acid cellulose hydrolysis process to produce ethanol from biomass.

    PubMed

    Nagle, N; Ibsen, K; Jennings, E

    1999-01-01

    Successful deployment of a bioethanol process depends on the integration of technologies that can be economically commercialized. Pretreatment and fermentation operations of the traditional enzymatic bioethanol-production process constitute the largest portion of the capital and operating costs. Cost reduction in these areas, through improved reactions and reduced capital, will improve the economic feasibility of a large-scale plant. A technoeconomic model was developed using the ASPEN Plus modeling software package. This model included a two-stage pretreatment operation with a co-current first stage and countercurrent second stage, a lignin adsorption unit, and a cofermentation unit. Data from kinetic modeling of the pretreatment reactions, verified by bench-scale experiments, were used to create the ASPEN Plus base model. Results from the initial pretreatment and fermentation yields of the two-stage system correlated well to the performance targets established by the model. The ASPEN Plus model determined mass and energy-balance information, which was supplied to an economic module to determine the required selling price of the ethanol. Several pretreatment process variables such as glucose yield, liquid: solid ratio, additional pretreatment stages, and lignin adsorption were varied to determine which parameters had the greatest effect on the process economics. Optimized values for these key variables became target values for the bench-scale research, either to achieve or identify as potential obstacles in the future commercialization process. Results from this modeling and experimentation sequence have led to the design of an advanced two-stage engineering- scale reactor for a dilute-acid hydrolysis process.

  12. Folic Acid Alters Methylation Profile of JAK-STAT and Long-Term Depression Signaling Pathways in Alzheimer's Disease Models.

    PubMed

    Li, Wen; Liu, Huan; Yu, Min; Zhang, Xumei; Zhang, Yan; Liu, Hongbo; Wilson, John X; Huang, Guowei

    2016-11-01

    Dementia has emerged as a major societal issue because of the worldwide aging population and the absence of any effective treatment. DNA methylation is an epigenetic mechanism that evidently plays a role in Alzheimer's disease (AD). Folate acts through one-carbon metabolism to support the methylation of multiple substrates including DNA. We aimed to test the hypothesis that folic acid supplementation alters DNA methylation profiles in AD models. Mouse Neuro-2a cells expressing human APP695 (N2a-APP cells) were incubated with folic acid (2.8-20 μmol/L). AD transgenic mice were fed either folate-deficient or control diets and gavaged daily with water or folic acid (600 μg/kg). Gene methylation profiles were determined by methylated DNA immunoprecipitation-DNA microarray (MeDIP-chip). Differentially methylated regions (DMRs) were determined by Quantitative Differentially Methylated Regions analysis, and differentially methylated genes (DMGs) carrying at least three DMRs were selected for pathway analysis. Folic acid up-regulated DNA methylation levels in N2a-APP cells and AD transgenic mouse brains. Functional network analysis of folic acid-induced DMGs in these AD models revealed subnetworks composed of 24 focus genes in the janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway and 12 focus genes in the long-term depression (LTD) signaling pathway. In conclusion, these results revealed a role for folic acid in the JAK-STAT and LTD signaling pathways which may be relevant to AD pathogenesis. This novel finding may stimulate reinvestigation of folic acid supplementation as a prophylactic or therapeutic treatment for AD.

  13. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2...-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2′-(1,2-diazenediyl)bis - and 2,2... butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2),...

  14. 40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2...-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2′-(1,2-diazenediyl)bis - and 2,2... butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2),...

  15. 75 FR 4292 - 2-Propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene and 2-methylpropyl 2-methyl-2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... AGENCY 40 CFR Part 180 2-Propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene and 2... residues of 2-propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene and 2-methylpropyl 2-methyl-2... permissible level for residues of 2-propenoic acid, 2-ethylhexyl ester, polymer with ethenylbenzene and...

  16. Radioiodinated methyl-branched fatty acids: Evaluation of catabolites formed in vivo

    SciTech Connect

    Knapp, F.F. Jr.; Reske, S.N.; Kirsch, G.; Ambrose, K.R.; Blystone, S.L.; Goodman, M.M.

    1987-01-01

    Radioiodinated terminal iodophenyl-substituted long-chain fatty acids containing either racemic mono-methyl or geminal dimethyl-branching in the alkyl chain have been shown to exhibit delayed myocardial clearance properties which make these agents useful for the SPECT evaluation of myocardial fatty acid uptake patterns. Although the myocardial clearance rate of 15-(p-iodophenyl)-3-R,S- methylpentadecanoic acid (BMIPP) is considerably delayed, in comparison with the IPPA straight-chain analogue, analysis of the radioiodinated lipids present in the outflow tract of isolated rat hearts administered BMIPP have clearly demonstrated the presence of a polar metabolite. The synthesis of ..beta..-hydroxy fatty acids has been developed to allow investigation of the possible formation of ..beta..-hydroxy catabolites in vivo. The preparation of ..beta..-hydroxy BMIPP and ..beta..-hydroxy IPPA are described, and the possible significance of their formation in vivo discussed. 4 figs.

  17. Fumaric Acid Production from Alkali-Pretreated Corncob by Fed-Batch Simultaneous Saccharification and Fermentation Combined with Separated Hydrolysis and Fermentation at High Solids Loading.

    PubMed

    Li, Xin; Zhou, Jin; Ouyang, Shuiping; Ouyang, Jia; Yong, Qiang

    2017-02-01

    Production of fumaric acid from alkali-pretreated corncob (APC) at high solids loading was investigated using a combination of separated hydrolysis and fermentation (SHF) and fed-batch simultaneous saccharification and fermentation (SSF) by Rhizopus oryzae. Four different fermentation modes were tested to maximize fumaric acid concentration at high solids loading. The highest concentration of 41.32 g/L fumaric acid was obtained from 20 % (w/v) APC at 38 °C in the combined SHF and fed-batch SSF process, compared with 19.13 g/L fumaric acid in batch SSF alone. The results indicated that a combination of SHF and fed-batch SSF significantly improved production of fumaric acid from lignocellulose by R. oryzae than that achieved with batch SSF at high solids loading.

  18. Demethylation of Methylated Arsenic Species during Generation of Arsanes with Tetrahydridoborate(1-) in Acidic Media.

    PubMed

    Marschner, Karel; Musil, Stanislav; Dědina, Jiří

    2016-06-21

    Demethylation during generation of volatile hydrides (HG), i.e. formation of noncorresponding arsanes from monomethylarsonic acid (MAs(V)), dimethylarsinic acid (DMAs(V)), and trimethylarsine oxide (TMAs(V)O) by the reaction of sodium tetrahydridoborate(1-) (THB) with different acids under analytical conditions, was investigated and characterized. Pronounced demethylation of MAs(V), DMAs(V), and TMAs(V)O was found during the reaction of THB with HCl, H2SO4, and HClO4, while HG from CH3COOH or TRIS buffer after prereduction with l-cysteine resulted in the formation of only the corresponding hydrides. In the case of HNO3 formation of corresponding hydrides was preserved for MAs(V) and DMAs(V) but not for TMAs(V)O. The extent of demethylation strongly depends on concentration of the acid and THB. It can be strongly suppressed in HCl medium by partial hydrolysis of THB with optimal concentration of acid before it reacts with MAs(V), DMAs(V), or TMAs(V)O. It appears that the demethylation is due to the action of specific hydrolytic products of THB (most probably by the first and second one).

  19. Stimulatory Effects of Acibenzolar-S-Methyl on Chlorogenic Acids Biosynthesis in Centella asiatica Cells.

    PubMed

    Ncube, Efficient N; Steenkamp, Paul A; Madala, Ntakadzeni E; Dubery, Ian A

    2016-01-01

    Centella asiatica is a perrenial herb that grows in tropical regions with numerous medicinal properties mostly attributed to the presence of pentacyclic triterpenoids. Interestingly, this plant also possess a significant amount of phenylpropanoid-derived chlorogenic acids (CGAs) that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer in combination with quinic acid and shikimic acid as precursor molecules. Applying a semi-targeted metabolomics-based approach, time and concentration studies were undertaken to evaluate the effect of the manipulation on cellular metabolism leading to CGA production. Phytochemical extracts were prepared using methanol and analyzed using a UHPLC-qTOF-MS platform. Data was processed and analyzed using multivariate data models. A total of four CGA-derivatives, annotated as trans-5-feruloylquinic acid, 3,5 di-caffeoylquinic acid, 3,5-O-dicaffeoyl-4-O-malonylquinic acid (irbic acid) and 3-caffeoyl, 5-feruloylquinic acid, were found to be upregulated by the acibenzolar-S-methyl treatment. To the best of our knowledge, this is the first report on the induction of CGA derivatives in this species. Contrary to expectations, the effects of precursor molecules on the levels of the CGAs were insignificant. However, a total of 16 metabolites, including CGA derivatives, were up-regulated by precursor treatment. Therefore, this study shows potential to biotechnologically manipulate C. asiatica cells to increase the production of these health beneficial CGAs.

  20. Stimulatory Effects of Acibenzolar-S-Methyl on Chlorogenic Acids Biosynthesis in Centella asiatica Cells

    PubMed Central

    Ncube, Efficient N.; Steenkamp, Paul A.; Madala, Ntakadzeni E.; Dubery, Ian A.

    2016-01-01

    Centella asiatica is a perrenial herb that grows in tropical regions with numerous medicinal properties mostly attributed to the presence of pentacyclic triterpenoids. Interestingly, this plant also possess a significant amount of phenylpropanoid-derived chlorogenic acids (CGAs) that have recently been reported to confer neuroprotective properties. In a biotechnological attempt to increase the biosynthesis of CGA-derivatives in cultured Centella cells, acibenzolar-S-methyl was applied as a xenobiotic inducer in combination with quinic acid and shikimic acid as precursor molecules. Applying a semi-targeted metabolomics-based approach, time and concentration studies were undertaken to evaluate the effect of the manipulation on cellular metabolism leading to CGA production. Phytochemical extracts were prepared using methanol and analyzed using a UHPLC-qTOF-MS platform. Data was processed and analyzed using multivariate data models. A total of four CGA-derivatives, annotated as trans-5-feruloylquinic acid, 3,5 di-caffeoylquinic acid, 3,5-O-dicaffeoyl-4-O-malonylquinic acid (irbic acid) and 3-caffeoyl, 5-feruloylquinic acid, were found to be upregulated by the acibenzolar-S-methyl treatment. To the best of our knowledge, this is the first report on the induction of CGA derivatives in this species. Contrary to expectations, the effects of precursor molecules on the levels of the CGAs were insignificant. However, a total of 16 metabolites, including CGA derivatives, were up-regulated by precursor treatment. Therefore, this study shows potential to biotechnologically manipulate C. asiatica cells to increase the production of these health beneficial CGAs. PMID:27733862