Improving efficiency of transport fuels production by thermal hydrolysis of waste activated sludge

Science.gov (United States)

Gulshin, Igor

2017-10-01

The article deals with issues of transport biofuels. Transport biofuels are an important element of a system of energy security. Moreover, as part of a system it is inextricably linked to the urban, rural or industrial infrastructure. The paper discusses methods of increasing the yield of biogas from anaerobic digesters at wastewater treatment plants. The thermal hydrolysis method was considered. The main advantages and drawbacks of this method were analyzed. The experimental biomass (from SNDOD-bioreactor) and high-organic substrate have been previously studied by respirometry methods. A biomethane potential of the investigated organic substrate has high rates because of substrate composition (the readily biodegradable substrate in the total composition takes about 85%). Waste activated sludge from SNDOD-bioreactor can be used for biofuel producing with high efficiency especially with pre-treatment like a thermal hydrolysis. Further studies have to consider the possibility of withdrawing inhibitors from waste activated sludge.

Pretreatment of wheat straw by nonionic surfactant-assisted dilute acid for enhancing enzymatic hydrolysis and ethanol production.

Science.gov (United States)

Qi, Benkun; Chen, Xiangrong; Wan, Yinhua

2010-07-01

Pretreating wheat straw (WS) with combined use of varied sulfuric acid concentration (0-3%, w/v) and Tween 20 concentration (0-1%) was investigated in an attempt to enhance the hydrolysis and fermentability of pretreated WS. Enzymatic hydrolysis yield of glucan and xylan and ethanol production by simultaneous saccharification and fermentation (SSF) of water-insoluble solids (WIS) were significantly affected by the amount of Tween 20 added during acid pretreatment. Any further addition of Tween 20 in either hydrolysis stage or fermentation stage only led to small increase in glucan conversion and ethanol production. Determination of adsorption of cellulases during hydrolysis showed that Tween 20-assisted acid treated straw solution contained more free cellulases than individual acid treated straw solution, indicating that modification of lignin surface by Tween 20 added during pretreatment likely occurred. In addition, the effects of pretreatment conditions on overall recovery of glucose and xylose after pretreatment and enzymatic hydrolysis were also investigated. Copyright 2010 Elsevier Ltd. All rights reserved.

Lactose hydrolysis potential and thermal stability of commercial β-galactosidase in UHT and skimmed milk

Directory of Open Access Journals (Sweden)

Alessandra BOSSO

2016-03-01

Full Text Available Abstract The commercial enzyme (E.C. = 3.2.1.23 from Kluyveromyces lactis (liquid and Aspergillus oryzae(lyophilized was investigated for its hydrolysis potential in lactose substrate, UHT milk, and skimmed milk at different concentrations (0.7; 1.0 and 1.5%, pH values (5.0; 6.0; 6.5 and 7.0, and temperature (30; 35; 40 and 55 ºC. High hydrolysis rates were observed for the enzyme from K. lactis at pH 7.0 and 40 ºC, and from A. oryzae at pH 5.0 and 55 ºC. The enzyme from K. lactis showed significantly higher hydrolysis rates when compared to A. oryzae. The effect of temperature and β-galactosidase concentration on the lactose hydrolysis in UHT milk was higher than in skimmed milk, for all temperatures tested. With respect to the thermal stability, a decrease in hydrolysis rate was observed at pH 6.0 at 35 ºC for K. lactisenzyme, and at pH 6.0 at 55 ºC for the enzyme from A. oryzae. This study investigate the hydrolysis of β-galactosidase in UHT and skimmed milk. The knowledge about the characteristics of the β-galactosidase fromK. lactis and A. oryzae enables to use it most efficiently to control the enzyme concentration, temperature, and pH in many industrial processes and product formulations.

Competitive reactions during synthesis of zinc aluminum layered double hydroxides by thermal hydrolysis of urea

DEFF Research Database (Denmark)

Staal, Line Boisen; Pushparaj, Suraj Shiv Charan; Forano, Claude

2017-01-01

Homogeneous precipitation by thermal hydrolysis of urea (“The urea method”) is preferred for the preparation of pure and highly crystalline layered double hydroxides (LDHs). However, our recent study revealed large concentrations of amorphous aluminum hydroxide (AOH) in several zinc(II) aluminum(...

Ethanol production from cashew apple bagasse: improvement of enzymatic hydrolysis by microwave-assisted alkali pretreatment.

Science.gov (United States)

Rodrigues, Tigressa Helena Soares; Rocha, Maria Valderez Ponte; de Macedo, Gorete Ribeiro; Gonçalves, Luciana R B

2011-07-01

In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses, and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L(-1) of NaOH (372 ± 12 and 355 ± 37 mg g(glucan)(-1) ) when 2% (w/v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment time (15-30 min) and microwave power (600-900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step, improvement on solid percentage (16% w/v) and enzyme load (30 FPU g (CAB-M) (-1) ) increased glucose concentration to 15 g L(-1). The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L(-1) and 1.41 g L(-1) h(-1), respectively.

Isolation of thermally stable cellulose nanocrystals by phosphoric acid hydrolysis.

Science.gov (United States)

Camarero Espinosa, Sandra; Kuhnt, Tobias; Foster, E Johan; Weder, Christoph

2013-04-08

On account of their intriguing mechanical properties, low cost, and renewable nature, high-aspect-ratio cellulose nanocrystals (CNCs) are an attractive component for many nanomaterials. Due to hydrogen bonding between their surface hydroxyl groups, unmodified CNCs (H-CNCs) aggregate easily and are often difficult to disperse. It is shown here that on account of ionic repulsion between charged surface groups, slightly phosphorylated CNCs (P-CNCs, average dimensions 31 ± 14 × 316 ± 127 nm, surface charge density = 10.8 ± 2.7 mmol/kg cellulose), prepared by controlled hydrolysis of cotton with phosphoric acid, are readily dispersible and form stable dispersions in polar solvents such as water, dimethyl sulfoxide, and dimethylformamide. Thermogravimetric analyses reveal that these P-CNCs exhibit a much higher thermal stability than partially sulfated CNCs (S-CNCs), which are frequently employed, but suffer from limited thermal stability. Nanocomposites of an ethylene oxide-epichlorohydrin copolymer and H-CNCs, S-CNCs, and P-CNCs were prepared, and their mechanical properties were studied by dynamic mechanical thermal analysis. The results show that P-CNCs offer a reinforcing capability that is comparable to that of H-CNCs or S-CNCs.

A comparison of product yields and inorganic content in process streams following thermal hydrolysis and hydrothermal processing of microalgae, manure and digestate.

Science.gov (United States)

Ekpo, U; Ross, A B; Camargo-Valero, M A; Williams, P T

2016-01-01

Thermal hydrolysis and hydrothermal processing show promise for converting biomass into higher energy density fuels. Both approaches facilitate the extraction of inorganics into the aqueous product. This study compares the behaviour of microalgae, digestate, swine and chicken manure by thermal hydrolysis and hydrothermal processing at increasing process severity. Thermal hydrolysis was performed at 170°C, hydrothermal carbonisation (HTC) was performed at 250°C, hydrothermal liquefaction (HTL) was performed at 350°C and supercritical water gasification (SCWG) was performed at 500°C. The level of nitrogen, phosphorus and potassium in the product streams was measured for each feedstock. Nitrogen is present in the aqueous phase as organic-N and NH3-N. The proportion of organic-N is higher at lower temperatures. Extraction of phosphorus is linked to the presence of inorganics such as Ca, Mg and Fe in the feedstock. Microalgae and chicken manure release phosphorus more easily than other feedstocks. Copyright © 2015. Published by Elsevier Ltd.

Thermal decay of rhodopsin: role of hydrogen bonds in thermal isomerization of 11-cis retinal in the binding site and hydrolysis of protonated Schiff base.

Science.gov (United States)

Liu, Jian; Liu, Monica Yun; Nguyen, Jennifer B; Bhagat, Aditi; Mooney, Victoria; Yan, Elsa C Y

2009-07-01

Although thermal stability of the G protein-coupled receptor rhodopsin is directly related to its extremely low dark noise level and has recently generated considerable interest, the chemistry behind the thermal decay process of rhodopsin has remained unclear. Using UV-vis spectroscopy and HPLC analysis, we have demonstrated that the thermal decay of rhodopsin involves both hydrolysis of the protonated Schiff base and thermal isomerization of 11-cis to all-trans retinal. Examining the unfolding of rhodopsin by circular dichroism spectroscopy and measuring the rate of thermal isomerization of 11-cis retinal in solution, we conclude that the observed thermal isomerization of 11-cis to all-trans retinal happens when 11-cis retinal is in the binding pocket of rhodopsin. Furthermore, we demonstrate that solvent deuterium isotope effects are involved in the thermal decay process by decreasing the rates of thermal isomerization and hydrolysis, suggesting that the rate-determining step of these processes involves breaking hydrogen bonds. These results provide insight into understanding the critical role of an extensive hydrogen-bonding network on stabilizing the inactive state of rhodopsin and contribute to our current understanding of the low dark noise level of rhodopsin, which enables this specialized protein to function as an extremely sensitive biological light detector. Because similar hydrogen-bonding networks have also been suggested by structural analysis of two other GPCRs, beta1 and beta2 adrenergic receptors, our results could reveal a general role of hydrogen bonds in facilitating GPCR function.

Effect of Cambi Thermal Hydrolysis Process-Anaerobic digestion treatment on concentrations on phthalate plasticisers in wastewater sludge

Science.gov (United States)

The impact of the recently implemented Cambi Thermal Hydrolysis Process™-Anaerobic Digestion (TH-AD) solids treatment method on concentrations of 4 phthalate plasticisers in wastewater sludge samples was explored in this study. Samples were analysed for diisononyl phthalate (DiNP), diisodecyl phthal...

Effects of surface proteins and lipids on molecular structure, thermal properties, and enzymatic hydrolysis of rice starch

Directory of Open Access Journals (Sweden)

Pan HU

Full Text Available Abstract Rice starches with different amylose contents were treated with sodium dodecyl sulfate (SDS to deplete surface proteins and lipids, and the changes in molecular structure, thermal properties, and enzymatic hydrolysis were evaluated. SDS treatment did not significantly change the molecular weight distribution, crystalline structure, short-range ordered degree, and gelatinization properties of starch, but significantly altered the pasting properties and increased the swelling power of starch. The removal of surface proteins and lipids increased the enzymatic hydrolysis and in vitro digestion of starch. The influences of removing surface proteins and lipids from starch on swelling power, pasting properties, and enzymatic hydrolysis were different among the various starches because of the differences in molecular structures of different starch styles. The aforementioned results indicated that removing the surface proteins and lipids from starch did not change the molecular structure but had significant effects on some functional properties.

Robotic-assisted thermal ablation of liver tumours

International Nuclear Information System (INIS)

Abdullah, Basri Johan Jeet; Yeong, Chai Hong; Goh, Khean Lee; Yoong, Boon Koon; Ho, Gwo Fuang; Yim, Carolyn Chue Wai; Kulkarni, Anjali

2015-01-01

This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

Robotic-assisted thermal ablation of liver tumours

Energy Technology Data Exchange (ETDEWEB)

Abdullah, Basri Johan Jeet; Yeong, Chai Hong [University of Malaya, Department of Biomedical Imaging and University of Malaya Research Imaging Centre, Faculty of Medicine, Kuala Lumpur (Malaysia); University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Goh, Khean Lee [University of Malaya, Department of Internal Medicine, Faculty of Medicine, Kuala Lumpur (Malaysia); Yoong, Boon Koon [University of Malaya, Department of Surgery, Faculty of Medicine, Kuala Lumpur (Malaysia); Ho, Gwo Fuang [University of Malaya, Department of Oncology, Faculty of Medicine, Kuala Lumpur (Malaysia); Yim, Carolyn Chue Wai [University of Malaya, Department of Anesthesia, Faculty of Medicine, Kuala Lumpur (Malaysia); Kulkarni, Anjali [Perfint Healthcare Corporation, Florence, OR (United States)

2015-01-15

This study aimed to assess the technical success, radiation dose, safety and performance level of liver thermal ablation using a computed tomography (CT)-guided robotic positioning system. Radiofrequency and microwave ablation of liver tumours were performed on 20 patients (40 lesions) with the assistance of a CT-guided robotic positioning system. The accuracy of probe placement, number of readjustments and total radiation dose to each patient were recorded. The performance level was evaluated on a five-point scale (5-1: excellent-poor). The radiation doses were compared against 30 patients with 48 lesions (control) treated without robotic assistance. Thermal ablation was successfully completed in 20 patients with 40 lesions and confirmed on multiphasic contrast-enhanced CT. No procedure related complications were noted in this study. The average number of needle readjustment was 0.8 ± 0.8. The total CT dose (DLP) for the entire robotic assisted thermal ablation was 1382 ± 536 mGy.cm, while the CT fluoroscopic dose (DLP) per lesion was 352 ± 228 mGy.cm. There was no statistically significant (p > 0.05) dose reduction found between the robotic-assisted versus the conventional method. This study revealed that robotic-assisted planning and needle placement appears to be safe, with high accuracy and a comparable radiation dose to patients. (orig.)

High-Temperature Adhesives for Thermally Stable Aero-Assist Technologies

Science.gov (United States)

Eberts, Kenneth; Ou, Runqing

2013-01-01

Aero-assist technologies are used to control the velocity of exploration vehicles (EVs) when entering Earth or other planetary atmospheres. Since entry of EVs in planetary atmospheres results in significant heating, thermally stable aero-assist technologies are required to avoid the high heating rates while maintaining low mass. Polymer adhesives are used in aero-assist structures because of the need for high flexibility and good bonding between layers of polymer films or fabrics. However, current polymer adhesives cannot withstand temperatures above 400 C. This innovation utilizes nanotechnology capabilities to address this need, leading to the development of high-temperature adhesives that exhibit high thermal conductivity in addition to increased thermal decomposition temperature. Enhanced thermal conductivity will help to dissipate heat quickly and effectively to avoid temperature rising to harmful levels. This, together with increased thermal decomposition temperature, will enable the adhesives to sustain transient high-temperature conditions.

Hydrolysis Batteries: Generating Electrical Energy during Hydrogen Absorption.

Science.gov (United States)

Xiao, Rui; Chen, Jun; Fu, Kai; Zheng, Xinyao; Wang, Teng; Zheng, Jie; Li, Xingguo

2018-02-19

The hydrolysis reaction of aluminum can be decoupled into a battery by pairing an Al foil with a Pd-capped yttrium dihydride (YH 2 -Pd) electrode. This hydrolysis battery generates a voltage around 0.45 V and leads to hydrogen absorption into the YH 2 layer. This represents a new hydrogen absorption mechanism featuring electrical energy generation during hydrogen absorption. The hydrolysis battery converts 8-15 % of the thermal energy of the hydrolysis reaction into usable electrical energy, leading to much higher energy efficiency compared to that of direct hydrolysis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A comparative study of thermal calcination and an alkaline hydrolysis method in the isolation of hydroxyapatite from Thunnus obesus bone

International Nuclear Information System (INIS)

Venkatesan, Jayachandran; Ryu, BoMi; Thomas, Noel Vinay; Kim, Se Kwon; Qian Zhongji

2011-01-01

In the present study, hydroxyapatite (HAp) was isolated from Thunnus obesus bone using alkaline hydrolysis and thermal calcination methods. The obtained ceramic has been characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction analysis (XRD), field-emission scanning electron microscopy, energy-dispersive x-ray analysis, transmission electron microscopy (TEM), selected area diffraction analysis, cytotoxic analysis and cell proliferation analysis. The results indicate that there are significant differences between the ceramics and T. obesus bone. FT-IR and TGA results affirmed that the collagen and organic moieties have been eliminated by both the proposed methods. XRD results were in agreement with JCPDS data. TEM and selective area diffraction images have signified that the thermal calcination method produces good crystallinity with dimensions 0.3-1.0 μm, whereas the alkaline hydrolysis method produces nanostructured HAp crystals with 17-71 nm length and 5-10 nm width. Biocompatibility of HAp crystals was evaluated by cytotoxicity and cell proliferation with human osteoblast-like cell MG-63.

A comparative study of thermal calcination and an alkaline hydrolysis method in the isolation of hydroxyapatite from Thunnus obesus bone

Energy Technology Data Exchange (ETDEWEB)

Venkatesan, Jayachandran; Ryu, BoMi; Thomas, Noel Vinay; Kim, Se Kwon [Department of Chemistry, Pukyong National University, Busan 608-737 (Korea, Republic of); Qian Zhongji, E-mail: sknkim@pknu.ac.kr [Marine Bioprocess Research Center, Pukyong National University, Busan 608-737 (Korea, Republic of)

2011-06-15

In the present study, hydroxyapatite (HAp) was isolated from Thunnus obesus bone using alkaline hydrolysis and thermal calcination methods. The obtained ceramic has been characterized by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), powder x-ray diffraction analysis (XRD), field-emission scanning electron microscopy, energy-dispersive x-ray analysis, transmission electron microscopy (TEM), selected area diffraction analysis, cytotoxic analysis and cell proliferation analysis. The results indicate that there are significant differences between the ceramics and T. obesus bone. FT-IR and TGA results affirmed that the collagen and organic moieties have been eliminated by both the proposed methods. XRD results were in agreement with JCPDS data. TEM and selective area diffraction images have signified that the thermal calcination method produces good crystallinity with dimensions 0.3-1.0 {mu}m, whereas the alkaline hydrolysis method produces nanostructured HAp crystals with 17-71 nm length and 5-10 nm width. Biocompatibility of HAp crystals was evaluated by cytotoxicity and cell proliferation with human osteoblast-like cell MG-63.

A process for producing lignin and volatile compounds from hydrolysis liquor.

Science.gov (United States)

Khazraie, Tooran; Zhang, Yiqian; Tarasov, Dmitry; Gao, Weijue; Price, Jacquelyn; DeMartini, Nikolai; Hupa, Leena; Fatehi, Pedram

2017-01-01

Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor. The thermal properties of the precipitates made from the acidification of hydrolysis liquor confirmed the volatile characteristics of precipitates. Membrane dialysis was effective in removing inorganic salts associated with lignin compounds. The purified lignin compounds had a glass transition temperature (Tg) of 180-190 °C, and were thermally stable. The results confirmed that lignin compounds present in hot water hydrolysis liquor had different characteristics. The acidification of hydrolysis liquor primarily removed the volatile compounds from hydrolysis liquor. Based on these results, a process for producing purified lignin and precipitates of volatile compounds was proposed.

The Research on Thermal Properties and Hydrophobility of the Native Starch/hydrolysis Starch Blends with Treated CaCO3 Powder

Science.gov (United States)

Liu, Chia-I.; Huang, Chi-Yuan

2008-08-01

In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60° to 95° when 15wt% treated CaCO3 was added. Treated CaCO3 was confirmed to improve the hydrophobility of starch blends effectively.

THE RESEARCH ON THERMAL PROPERTIES AND HYDROPHOBILITY OF THE NATIVE STARCH/HYDROLYSIS STARCH BLENDS WITH TREATED CaCO3 POWDER

International Nuclear Information System (INIS)

Liu, C.-I; Huang, C.-Y.

2008-01-01

In this research, hydrolysis starch was added into the starch blends to study the thermal properties. The enthalpy of blends had a significant decrease to 109J/g as content of treated CaCO 3 increased to 5wt%. The modified starch was degraded slightly to produce glucose in the hydrolysis treatment. The amount of glucose in native starch and hydrolysis starch was 0.09 μmol and 0.14 μmol by the DNS measurement. Moreover, CaCO 3 treated with titanium coupling agent was also added to improve miscibility and hydrophobility in the starch blends. The contact angle of the blends increased from 60 deg. to 95 deg. when 15wt% treated CaCO 3 was added. Treated CaCO 3 was confirmed to improve the hydrophobility of starch blends effectively

Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis.

Science.gov (United States)

Baks, Tim; Bruins, Marieke E; Matser, Ariette M; Janssen, Anja E M; Boom, Remko M

2008-01-23

Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with alpha-amylase from Bacillus licheniformis were compared. Suspensions of native starch or starch gelatinized at different conditions either with or without enzyme were hydrolyzed. During hydrolysis, the oligosaccharide concentration, the dextrose equivalent, and the enzyme activity were determined. We found that the hydrolyzate composition was affected by the type of starch pretreatment and the enzyme addition point but that it was just minimally affected by the pressure applied during hydrolysis, as long as gelatinization was complete. The differences between hydrolysis of thermally gelatinized, high-pressure gelatinized, and native starch were explained by considering the granule structure and the specific surface area of the granules. These results show that the hydrolyzate composition can be influenced by choosing different process sequences and conditions.

Ultrasound-assisted acid hydrolysis of cellulose to chemical building blocks: Application to furfural synthesis.

Science.gov (United States)

Santos, Daniel; Silva, Ubiratan F; Duarte, Fabio A; Bizzi, Cezar A; Flores, Erico M M; Mello, Paola A

2018-01-01

In this work, the use of ultrasound energy for the production of furanic platforms from cellulose was investigated and the synthesis of furfural was demonstrated. Several systems were evaluated, as ultrasound bath, cup horn and probe, in order to investigate microcrystalline cellulose conversion using simply a diluted acid solution and ultrasound. Several acid mixtures were evaluated for hydrolysis, as diluted solutions of HNO 3 , H 2 SO 4 , HCl and H 2 C 2 O 4 . The influence of the following parameters in the ultrasound-assisted acid hydrolysis (UAAH) were studied: sonication temperature (30 to 70°C) and ultrasound amplitude (30 to 70% for a cup horn system) for 4 to 8molL -1 HNO 3 solutions. For each evaluated condition, the products were identified by ultra-performance liquid chromatography with high-resolution time-of-flight mass spectrometry (UPLC-ToF-MS), which provide accurate information regarding the products obtained from biomass conversion. The furfural structure was confirmed by nuclear magnetic resonance ( 1 H and 13 C NMR) spectroscopy. In addition, cellulosic residues from hydrolysis reaction were characterized using scanning electron microscopy (SEM), which contributed for a better understanding of physical-chemical effects caused by ultrasound. After process optimization, a 4molL -1 HNO 3 solution, sonicated for 60min at 30°C in a cup horn system at 50% of amplitude, lead to 78% of conversion to furfural. This mild temperature condition combined to the use of a diluted acid solution represents an important contribution for the selective production of chemical building blocks using ultrasound energy. Copyright © 2017 Elsevier B.V. All rights reserved.

CFD simulation of transient stage of continuous countercurrent hydrolysis of canola oil

KAUST Repository

Wang, Weicheng

2012-08-01

Computational Fluid Dynamic (CFD) modeling of a continuous countercurrent hydrolysis process was performed using ANSYS-CFX. The liquid properties and flow behavior such as density, specific heats, dynamic viscosity, thermal conductivity, and thermal expansivity as well as water solubility of the hydrolysis components triglyceride, diglyceride, monoglyceride, free fatty acid, and glycerol were calculated. Chemical kinetics for the hydrolysis reactions were simulated in this model by applying Arrhenius parameters. The simulation was based on actual experimental reaction conditions including temperature and water-to-oil ratio. The results not only have good agreement with experimental data but also show instantaneous distributions of concentrations of every component in hydrolysis reaction. This model provided visible insight into the continuous countercurrent hydrolysis process. © 2012 Elsevier Ltd.

CFD simulation of transient stage of continuous countercurrent hydrolysis of canola oil

KAUST Repository

Wang, Weicheng; Natelson, Robert H.; Stikeleather, Larry F.; Roberts, William L.

2012-01-01

Computational Fluid Dynamic (CFD) modeling of a continuous countercurrent hydrolysis process was performed using ANSYS-CFX. The liquid properties and flow behavior such as density, specific heats, dynamic viscosity, thermal conductivity, and thermal expansivity as well as water solubility of the hydrolysis components triglyceride, diglyceride, monoglyceride, free fatty acid, and glycerol were calculated. Chemical kinetics for the hydrolysis reactions were simulated in this model by applying Arrhenius parameters. The simulation was based on actual experimental reaction conditions including temperature and water-to-oil ratio. The results not only have good agreement with experimental data but also show instantaneous distributions of concentrations of every component in hydrolysis reaction. This model provided visible insight into the continuous countercurrent hydrolysis process. © 2012 Elsevier Ltd.

Cellulase hydrolysis of unsorted MSW

DEFF Research Database (Denmark)

Jensen, Jacob Wagner; Felby, Claus; Jørgensen, Henning

2011-01-01

A recent development in waste management and engineering has shown that the cellulase can be used for the liquefaction of organic fractions in household waste. The focus of this study was to optimize the enzyme hydrolysis of thermally treated municipal solid waste (MSW) by the addition of surfact......A recent development in waste management and engineering has shown that the cellulase can be used for the liquefaction of organic fractions in household waste. The focus of this study was to optimize the enzyme hydrolysis of thermally treated municipal solid waste (MSW) by the addition...... of calcium, potassium, sodium, chloride and others that may affect cellulolytic enzymes. Cellulase performance showed no effect of adding the metal ion-chelating agent EDTA to the solution. The cellulases were stable, tolerated and functioned in the presence of several contaminants....

Thermally-assisted Magma Emplacement Explains Restless Calderas.

Science.gov (United States)

Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

2017-08-11

Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

MgCoAl and NiCoAl LDHs synthesized by the hydrothermal urea hydrolysis method: Structural characterization and thermal decomposition

International Nuclear Information System (INIS)

Chagas, L.H.; De Carvalho, G.S.G.; Do Carmo, W.R.; San Gil, R.A.S.; Chiaro, S.S.X.; Leitão, A.A.; Diniz, R.; De Sena, L.A.; Achete, C.A.

2015-01-01

Highlights: • We synthesized MgCoAl and NiCoAl LDHs by the urea hydrolysis method. • Aluminum rich and crystalline materials have been formed. • The calcination of the LDHs generated mixed oxides with high surface areas. - Abstract: Layered double hydroxides (LDHs) with Mg/Co/Al and Ni/Co/Al were synthesized for the first time by the urea hydrolysis method. The experimental conditions promoted aluminum rich and crystalline materials. The formation of LDHs was investigated by powder X-ray diffraction (XRD), chemical analysis, solid state nuclear magnetic resonance with magic angle spinning ( 27 Al-MAS-NMR), simultaneous thermogravimetric/differential thermal analysis (TGA/DTA), FTIR spectroscopy, scanning electron microscopy (SEM), and N 2 adsorption–desorption experiments. A single phase corresponding to LDH could be obtained in all the investigated compositions. Thermal calcination of these LDHs at 500 °C resulted in the formation of solid solutions in which Al 3+ was dissolved. All the calcined materials have rock-salt like structures and high surface areas

At-line gas chromatographic-mass spectrometric analysis of fatty acid profiles of green microalgae using a direct thermal desorption interface

NARCIS (Netherlands)

Blokker, P.; Pel, R.; Akoto, L.; Udo, A.; Brinkman, U.A.Th.; Vreuls, R.J.J.

2002-01-01

Thermally assisted hydrolysis and methylation¯gas chromatography (THM¯GC) is an important tool to analyse fatty acid in complex matrices. Since THM¯GC has major drawbacks such as isomerisation when applied to fatty acids in natural matrices, a direct thermal desorption (DTD) interface and an

Low frequency ultrasonic-assisted hydrolysis of starch in the presence of α-amylase.

Science.gov (United States)

Gaquere-Parker, Anne; Taylor, Tamera; Hutson, Raihannah; Rizzo, Ashley; Folds, Aubrey; Crittenden, Shastina; Zahoor, Neelam; Hussein, Bilal; Arruda, Aaron

2018-03-01

Hydrolysis of starch is an important process in the food industry and in the production of bioethanol or smaller carbohydrate molecules that can be used as starting blocks for chemical synthesis. Such hydrolysis can be enhanced by lowering the pH, heating the reaction mixture or catalyzing the reaction with enzymes. This study reports the effect of sonication on the reaction rate of starch hydrolysis at different temperatures, in the presence or absence of alpha-amylase. Starch Azure, a commercially available potato starch covalently linked with Remazol Brilliant Blue, has been chosen since its hydrolysis releases a blue dye, which concentration can be monitored by UV Vis spectroscopy. Ultrasounds, regardless of experimental conditions, provide the highest reaction rate for such hydrolysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous thermal hydrolysis and energy integration in sludge anaerobic digestion plants.

Science.gov (United States)

Fdz-Polanco, F; Velazquez, R; Perez-Elvira, S I; Casas, C; del Barrio, D; Cantero, F J; Fdz-Polanco, M; Rodriguez, P; Panizo, L; Serrat, J; Rouge, P

2008-01-01

A thermal hydrolysis pilot plant with direct steam injection heating was designed and constructed. In a first period the equipment was operated in batch to verify the effect of sludge type, pressure and temperature, residence time and solids concentration. Optimal operation conditions were reached for secondary sludge at 170 degrees C, 7 bar and 30 minutes residence time, obtaining a disintegration factor higher than 10, methane production increase by 50% and easy centrifugation In a second period the pilot plant was operated working with continuous feed, testing the efficiency by using two continuous anaerobic digester operating in the mesophilic and thermophilic range. Working at 12 days residence time, biogas production increases by 40-50%. Integrating the energy transfer it is possible to design a self-sufficient system that takes advantage of this methane increase to produce 40% more electric energy. (c) IWA Publishing 2008.

MgCoAl and NiCoAl LDHs synthesized by the hydrothermal urea hydrolysis method: Structural characterization and thermal decomposition

Energy Technology Data Exchange (ETDEWEB)

Chagas, L.H., E-mail: lhchagas-prometro@inmetro.gov.br [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); Instituto Nacional de Metrologia Qualidade e Tecnologia, Divisão de Metrologia de Materiais, 25250-020 Duque de Caxias, RJ (Brazil); De Carvalho, G.S.G.; Do Carmo, W.R. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); San Gil, R.A.S. [Universidade Federal do Rio de Janeiro, Instituto de Química, 21949-900 Rio de Janeiro, RJ (Brazil); Chiaro, S.S.X. [PETROBRAS-CENPES, 21941-915 Rio de Janeiro, RJ (Brazil); Leitão, A.A.; Diniz, R. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); De Sena, L.A.; Achete, C.A. [Instituto Nacional de Metrologia Qualidade e Tecnologia, Divisão de Metrologia de Materiais, 25250-020 Duque de Caxias, RJ (Brazil)

2015-04-15

Highlights: • We synthesized MgCoAl and NiCoAl LDHs by the urea hydrolysis method. • Aluminum rich and crystalline materials have been formed. • The calcination of the LDHs generated mixed oxides with high surface areas. - Abstract: Layered double hydroxides (LDHs) with Mg/Co/Al and Ni/Co/Al were synthesized for the first time by the urea hydrolysis method. The experimental conditions promoted aluminum rich and crystalline materials. The formation of LDHs was investigated by powder X-ray diffraction (XRD), chemical analysis, solid state nuclear magnetic resonance with magic angle spinning ({sup 27}Al-MAS-NMR), simultaneous thermogravimetric/differential thermal analysis (TGA/DTA), FTIR spectroscopy, scanning electron microscopy (SEM), and N{sub 2} adsorption–desorption experiments. A single phase corresponding to LDH could be obtained in all the investigated compositions. Thermal calcination of these LDHs at 500 °C resulted in the formation of solid solutions in which Al{sup 3+} was dissolved. All the calcined materials have rock-salt like structures and high surface areas.

STDAC: Solar Thermal Design Assistance Center annual report fiscal year 1994

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

The Solar Thermal Design Assistance Center (STDAC) at Sandia is a resource provided by the DOE Solar Thermal Program. The STDAC`s major objective is to accelerate the use of solar thermal systems by providing direct technical assistance to users in industry, government, and foreign countries; cooperating with industry to test, evaluate, and develop renewable energy systems and components; and educating public and private professionals, administrators, and decision makers. This FY94 report highlights the activities and accomplishments of the STDAC. In 1994, the STDAC continued to provide significant direct technical assistance to domestic and international organizations in industry, government, and education, Applying solar thermal technology to solve energy problems is a vital element of direct technical assistance. The STDAC provides information on the status of new, existing, and developing solar technologies; helps users screen applications; predicts the performance of components and systems; and incorporates the experience of Sandia`s solar energy personnel and facilities to provide expert guidance. The STDAC directly enhances the US solar industry`s ability to successfully bring improved systems to the marketplace. By collaborating with Sandia`s Photovoltaic Design Assistance Center and the National Renewable Energy Laboratory the STDAC is able to offer each customer complete service in applying solar thermal technology. At the National Solar Thermal Test Facility the STDAC tests and evaluates new and innovative solar thermal technologies. Evaluations are conducted in dose cooperation with manufacturers, and the results are used to improve the product and/or quantify its performance characteristics. Manufacturers, in turn, benefit from the improved design, economic performance, and operation of their solar thermal technology. The STDAC provides cost sharing and in-kind service to manufacturers in the development and improvement of solar technology.

A complete degradation of organophosphates by microwave-assisted hydrolysis

Czech Academy of Sciences Publication Activity Database

Jansa, Petr; Čechová, Lucie; Janeba, Zlatko

2016-01-01

Roč. 3, č. 3 (2016), s. 219-226 ISSN 2213-3356 R&D Projects: GA MV VG20102015046 Institutional support: RVO:61388963 Keywords : organophosphates * microwave irradiation * hydrolysis Subject RIV: CC - Organic Chemistry

Thermopressure hydrolysis. Paper; Thermodruckhydrolyse. Paper

Energy Technology Data Exchange (ETDEWEB)

Stahl, R. [Scheuchl GmbH, Ortenburg (Germany); Prechtl, S. [Applikations- und Technikzentrum fuer Energieverfahrens-, Umwelt- und Stroemungstechnik (ATZ-EVUS), Sulzbach-Rosenberg (Germany)

2000-12-01

This paper presents a processing method which consists in thermal hydrolysis and subsequent anaerobic fermentation and is especially well suited for wet, low-structure organic wastes. [German] Das vorgestellte Verwertungsverfahren bestehend aus thermischer Hydrolyse und anschliessender anaerober Vergaerung eignet sich besonders fuer nasse, strukturarme organische Abfaelle. (orig.)

Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

International Nuclear Information System (INIS)

Fernandes, Kátia F.; Cortijo-Triviño, David; Batista, Karla A.; Ulhoa, Cirano J.; García-Ruiz, Pedro A.

2013-01-01

In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na 2 SO 4 . Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na 2 SO 4 was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h

Chitin hydrolysis assisted by cell wall degrading enzymes immobilized of Thichoderma asperellum on totally cinnamoylated D-sorbitol beads

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Kátia F., E-mail: katia@icb.ufg.br [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Cortijo-Triviño, David [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain); Batista, Karla A.; Ulhoa, Cirano J. [Departamento de Bioquímica e Biologia Molecular, Instituo de Ciências Biológicas, Universidade Federal de Goiás, Cx. Postal 131, 74001-970 Goiânia, GO (Brazil); García-Ruiz, Pedro A. [Grupo de Química de Carbohidratos y Biotecnología de Alimentos (QCBA), Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Espinardo, Murcia (Spain)

2013-07-01

In this study, cell wall degrading enzymes produced by Thrichoderma asperellum (TCWDE) were immobilized on totally cinnamoylated D-sorbitol (TCNSO) beads and used for chitin hydrolysis. In order to optimize immobilization efficiency, the reaction time was varied from 2 to 12 h and reactions were conducted in the presence or absence of Na{sub 2}SO{sub 4}. Immobilized enzymes were analysed concerning to thermal and operational stability. Immobilization in presence of Na{sub 2}SO{sub 4} was 54% more efficient than immobilization in absence of salt. After optimization, 32% of the total enzyme offered was immobilized, with 100% of bounding efficiency, measured as the relation between protein and enzyme immobilized. Free and TCNSO–TCWDE presented very similar kinetics with maximum hydrolysis reached at 90 min of reaction. Thermal stability of both free and TCNSO–TCWDE was similar, with losses in activity after 55 °C. Moreover, free and TCNSO–TCWDE retained 100% activity after 3 h incubation at 55 °C. TCNSO–TCWDE were used in a bath-wise reactor during 14 cycles, producing 1825 μg of N-acetylglucosamine (NAG) maintaining 83% of initial activity. - Highlights: • TCWDE immobilized on TCNSO, a support with highly hydrophobic character • New immobilization strategy for immobilization on a hydrophobic support • TCNSO–TCWDE were retained during washes and during incubation at 55 °C for 3 h.

Thermal hydrolysis of sludge and the use of hydrolysate as carbon source for denitrification

Energy Technology Data Exchange (ETDEWEB)

Barlindhaug, J

1995-10-01

As a consequence of the North Sea- and the Baltic Sea Treaties as well as the Wastewater Directive of the EU, several large wastewater treatment plants discharging to sensitive receiving waters have to include phosphorus as well as nitrogen removal. This thesis evaluates the so called NTH-process for nutrient removal. In this process pre-precipitation is used in front of a biological nitrogen removal step that is based on a combination of pre- and post-denitrification in moving bed biofilm reactors. The biological step is followed by a final separation step, possibly after coagulant addition. Carbon source for the post denitrification step is made available by hydrolysis of the sludge produced. The idea is that the particulate organic matter, which in a traditional pre-denitrification step would have to be enzymatically hydrolyzed, can be more efficiently hydrolyzed in a concentrated sidestream and used in a post-denitrification step. In the thesis hydrolyzed sludge is used as a carbon source for denitrification. The objective is to investigate the influence of varying hydrolysis conditions on the composition and amount of the thermal hydrolysate produced, as well as the quality of the hydrolysate as a carbon source for denitrification. 201 refs., 78 refs., 53 tabs.

Pressure-assisted thermal sterilization of soup

Science.gov (United States)

Shibeshi, Kidane; Farid, Mohammed M.

2010-12-01

The overall efficiency of an existing scale-up pressure-assisted thermal sterilization (PATS) unit was investigated with regards to inactivation of Geobacillus stearothermophilus spores suspended in pumpkin soup. The PATS unit is a double pipe heat exchanger in which the soup is pumped into its inner high pressure tube and constrained by two high pressure valves, while steam is continuously passed through the annular region to heat the content. The technology is based on pressure generation by thermal expansion of the liquid in an enclosure. In this work, the addition of an air line to push the treated liquid food out of the existing PATS unit has improved the overall quality of the treated samples, as evidenced by achieving higher log reduction of the spores. Compared with thermal processing, the application of PATS shows the potential for lowering the thermal treatment temperature, offering improved food quality.

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

Science.gov (United States)

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 H 2 SO 4 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.

Influence of Culture Media on Detection of Carbapenem Hydrolysis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

Science.gov (United States)

Ramos, Ana Carolina; Carvalhaes, Cecília Godoy; Cordeiro-Moura, Jhonatha Rodrigo; Rockstroh, Anna Carolina; Machado, Antonia Maria Oliveira; Gales, Ana Cristina

2016-07-01

In this study, we evaluated the influence of distinct bacterial growth media on detection of carbapenemase hydrolysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. False-negative results were observed for OXA-25-, OXA-26-, and OXA-72-producing Acinetobacter baumannii isolates grown on MacConkey agar medium. The other culture media showed 100% sensitivity and 100% specificity for detecting carbapenemase. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Influence of thermal processing on hydrolysis and stability of folate poly-gamma-glutamates in broccoli (Brassica oleracea var. italica), carrot (Daucus carota) and tomato (Lycopersicon esculentum).

Science.gov (United States)

Munyaka, Ann Wambui; Verlinde, Philippe; Mukisa, Ivan Muzira; Oey, Indrawati; Van Loey, Ann; Hendrickx, Marc

2010-04-14

The folate poly-gamma-glutamate profile, their concentrations, and hydrolysis by endogenous gamma-glutamyl hydrolase (GGH) were evaluated in broccoli, carrot and tomato. Further studies on the effect of time and temperature on folate poly-gamma-glutamate hydrolysis and stability were carried out in broccoli since this vegetable showed the highest long-chain and total folate poly-gamma-glutamate concentration. The evolution of l-ascorbic acid, total phenols and Trolox equivalent antioxidant capacity (TEAC) values was evaluated in parallel. Upon thermal inactivation of GGH prior to crushing, it was observed that broccoli, carrot and tomato contained poly-gamma-glutamates with one to seven glutamate residues but differed in the predominant poly-gamma-glutamates. Crushing of raw broccoli, carrot and tomato resulted in significant poly-gamma-glutamate profile changes in broccoli and carrot (indicating GGH-catalyzed hydrolysis) but not in tomato. In this study, the actual crushing of raw broccoli matrix had a greater effect on folate poly-gamma-glutamate hydrolysis than incubation conditions (0-30 min at 25-55 degrees C). During treatments at 25-140 degrees C, folate retention was higher at 80 and 100 degrees C than at the other temperatures. A similar trend in thermal stability was observed for folates, vitamin C, total phenols and TEAC value, an indication that conditions that result in endogenous antioxidants degradation might also result in folate degradation.

Total control of chromium in tanneries - thermal decomposition of filtration cake from enzymatic hydrolysis of chrome shavings.

Science.gov (United States)

Kocurek, P; Kolomazník, K; Bařinová, M; Hendrych, J

2017-04-01

This paper deals with the problem of chromium recovery from chrome-tanned waste and thus with reducing the environmental impact of the leather industry. Chrome-tanned waste was transformed by alkaline enzymatic hydrolysis promoted by magnesium oxide into practically chromium-free, commercially applicable collagen hydrolysate and filtration cake containing a high portion of chromium. The crude and magnesium-deprived chromium cakes were subjected to a process of thermal decomposition at 650°C under oxygen-free conditions to reduce the amount of this waste and to study the effect of magnesium removal on the resulting products. Oxygen-free conditions were applied in order to prevent the oxidation of trivalent chromium into the hazardous hexavalent form. Thermal decomposition products from both crude and magnesium-deprived chrome cakes were characterized by high chromium content over 50%, which occurred as eskolaite (Cr 2 O 3 ) and magnesiochromite (MgCr 2 O 4 ) crystal phases, respectively. Thermal decomposition decreased the amount of chrome cake dry feed by 90%. Based on the performed experiments, a scheme for the total control of chromium in the leather industry was designed.

Development of a Combined Trifluoroacetic Acid Hydrolysis and HPLC-ELSD Method to Identify and Quantify Inulin Recovered from Jerusalem artichoke Assisted by Ultrasound Extraction

Directory of Open Access Journals (Sweden)

Shuyi Li

2018-05-01

Full Text Available Over the last years, inulin, a fructan mixture consisting of oligosaccharides and polysaccharides, has attracted more and more attention from both food industry and researchers, due to its unique functional properties as a natural resource. Therefore, there is an increased interest in the extraction and quantification of inulin for its valorization from inulin rich plants, wastes and by-products. In this work, ultrasonic treatment was applied for inulin extraction, observing a great impact of extraction temperature and ultrasonic power on the inulin content in the obtained extracts. A combined process including trifluoroacetic acid (TFA-assisted hydrolysis and analysis with high performance liquid chromatography equipped with evaporative light scattering detector (HPLC-ELSD was developed to quantify inulin content. The effect of hydrolysis parameters was investigated, obtaining the optimal conditions after using TFA at a concentration of 1 mg/mL, hydrolysis temperature of 90 °C, and hydrolysis duration of 60 min. The good linearity (>0.995, precision, recovery (100.27%, and stability obtained during the validation process showed that this developed method allows the quantification of total inulin content in the samples analyzed. This combined method may also contribute to the investigation of the functional properties of inulin (e.g., as prebiotic.

Post-anaerobic digestion thermal hydrolysis of sewage sludge and food waste: Effect on methane yields, dewaterability and solids reduction.

Science.gov (United States)

Svensson, Kine; Kjørlaug, Oda; Higgins, Matthew J; Linjordet, Roar; Horn, Svein J

2018-04-01

Post-anaerobic digestion (PAD) treatment technologies have been suggested for anaerobic digestion (AD) to improve process efficiency and assure hygenization of organic waste. Because AD reduces the amount of organic waste, PAD can be applied to a much smaller volume of waste compared to pre-digestion treatment, thereby improving efficiency. In this study, dewatered digestate cakes from two different AD plants were thermally hydrolyzed and dewatered, and the liquid fraction was recirculated to a semi-continuous AD reactor. The thermal hydrolysis was more efficient in relation to methane yields and extent of dewaterability for the cake from a plant treating waste activated sludge, than the cake from a plant treating source separated food waste (SSFW). Temperatures above 165 °C yielded the best results. Post-treatment improved volumetric methane yields by 7% and the COD-reduction increased from 68% to 74% in a mesophilic (37 °C) semi-continuous system despite lowering the solid retention time (from 17 to 14 days) compared to a conventional system with pre-treatment of feed substrates at 70 °C. Results from thermogravimetric analysis showed an expected increase in maximum TS content of dewatered digestate cake from 34% up to 46% for the SSFW digestate cake, and from 17% up to 43% in the sludge digestate cake, after the PAD thermal hydrolysis process (PAD-THP). The increased dewatering alone accounts for a reduction in wet mass of cake leaving the plant of 60% in the case of sludge digestate cake. Additionaly, the increased VS-reduction will contribute to further reduce the mass of wet cake. Copyright © 2018 Elsevier Ltd. All rights reserved.

The characteristic and dispersion stability of nanocellulose produced by mixed acid hydrolysis and ultrasonic assistance.

Science.gov (United States)

Niu, Fuge; Li, Mengya; Huang, Qi; Zhang, Xiuzhen; Pan, Weichun; Yang, Jiansheng; Li, Jianrong

2017-06-01

Axiolitic shape nanocellulose particles were prepared using a combined mixed acid hydrolysis and ultrasonic treatment. The crystallinity, morphology and stability properties of cellulose were characterized to investigate the mechanism of nanocellulose formation and stability. It was found the hydrodynamic radius decreased from 205nm to 89nm, and the crystallinity index of the nanocellulose increased from 62.90% to 72.31% with an increase in hydrolysis time from 2 to 10h. Sulfate esters and sulfonate group were present in the nanocellulose, and released more COH groups after hydrolysis. The ζ-potential of cellulose decreased from -11.5 to -43.8mV after 10h of hydrolysis. These results illustrated the amorphous characteristic of cellulose was removed after acid hydrolysis and ultrasonic treatment. The higher ζ-potential and relatively small cellulose particles caused a more stable suspension, suggesting that electrostatic interactions played an important role in maintaining the stability and dispersibility of the nanocellulose particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation and characterization of dialdehyde starch by one-step acid hydrolysis and oxidation.

Science.gov (United States)

Zuo, Yingfeng; Liu, Wenjie; Xiao, Junhua; Zhao, Xing; Zhu, Ying; Wu, Yiqiang

2017-10-01

Dialdehyde starch was prepared by one-step synthesis of acid hydrolysis and oxidation, using corn starch as the raw material, sodium periodate (NaIO 4 ) as the oxidant, and hydrochloric acid (HCl) as the acid solution. The prepared dialdehyde starch was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The results confirmed that oxidation occurred between the starch and NaIO 4 . The acid hydrolysis reaction reduced the molecular weight of starch and effectively improved the aldehyde group contents (92.7%). Scanning electron microscope (SEM) analysis indicated that the average particle size decreased after acid hydrolysis and oxidation reaction. X-ray diffraction (XRD) and thermal gravimetric analyzer (TGA) analysis demonstrated that the crystallinity of the obtained dialdehyde starch showed a downward trend and a decelerated thermal decomposition rate. The starch after acid hydrolysis and oxidation exhibited lower hot paste viscosity and higher reactivity. Copyright © 2017. Published by Elsevier B.V.

Easy Fabrication of Highly Thermal-Stable Cellulose Nanocrystals Using Cr(NO33 Catalytic Hydrolysis System: A Feasibility Study from Macro- to Nano-Dimensions

Directory of Open Access Journals (Sweden)

You Wei Chen

2017-01-01

Full Text Available This study reported on the feasibility and practicability of Cr(NO33 hydrolysis to isolate cellulose nanocrystals (CNCCr(NO33 from native cellulosic feedstock. The physicochemical properties of CNCCr(NO33 were compared with nanocellulose isolated using sulfuric acid hydrolysis (CNCH2SO4. In optimum hydrolysis conditions, 80 °C, 1.5 h, 0.8 M Cr(NO33 metal salt and solid–liquid ratio of 1:30, the CNCCr(NO33 exhibited a network-like long fibrous structure with the aspect ratio of 15.7, while the CNCH2SO4 showed rice-shape structure with an aspect ratio of 3.5. Additionally, Cr(NO33-treated CNC rendered a higher crystallinity (86.5% ± 0.3% with high yield (83.6% ± 0.6% as compared to the H2SO4-treated CNC (81.4% ± 0.1% and 54.7% ± 0.3%, respectively. Furthermore, better thermal stability of CNCCr(NO33 (344 °C compared to CNCH2SO4 (273 °C rendered a high potential for nanocomposite application. This comparable effectiveness of Cr(NO33 metal salt provides milder hydrolysis conditions for highly selective depolymerization of cellulosic fiber into value-added cellulose nanomaterial, or useful chemicals and fuels in the future.

Anaerobic co-digestion of coffee husks and microalgal biomass after thermal hydrolysis.

Science.gov (United States)

Passos, Fabiana; Cordeiro, Paulo Henrique Miranda; Baeta, Bruno Eduardo Lobo; de Aquino, Sergio Francisco; Perez-Elvira, Sara Isabel

2018-04-01

Residual coffee husks after seed processing may be better profited if bioconverted into energy through anaerobic digestion. This process may be improved by implementing a pretreatment step and by co-digesting the coffee husks with a more liquid biomass. In this context, this study aimed at evaluating the anaerobic co-digestion of coffee husks with microalgal biomass. For this, both substrates were pretreated separately and in a mixture for attaining 15% of total solids (TS), which was demonstrated to be the minimum solid content for pretreatment of coffee husks. The results showed that the anaerobic co-digestion presented a synergistic effect, leading to 17% higher methane yield compared to the theoretical value of both substrates biodegraded separately. Furthermore, thermal hydrolysis pretreatment increased coffee husks anaerobic biodegradability. For co-digestion trials, the highest values were reached for pretreatment at 120 °C for 60 min, which led to 196 mLCH 4 /gVS and maximum methane production rate of 0.38 d -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamic modeling and validation of a lignocellulosic enzymatic hydrolysis process

DEFF Research Database (Denmark)

Prunescu, Remus Mihail; Sin, Gürkan

2013-01-01

The enzymatic hydrolysis process is one of the key steps in second generation biofuel production. After being thermally pretreated, the lignocellulosic material is liquefied by enzymes prior to fermentation. The scope of this paper is to evaluate a dynamic model of the hydrolysis process...... on a demonstration scale reactor. The following novel features are included: the application of the Convection–Diffusion–Reaction equation to a hydrolysis reactor to assess transport and mixing effects; the extension of a competitive kinetic model with enzymatic pH dependency and hemicellulose hydrolysis......; a comprehensive pH model; and viscosity estimations during the course of reaction. The model is evaluated against real data extracted from a demonstration scale biorefinery throughout several days of operation. All measurements are within predictions uncertainty and, therefore, the model constitutes a valuable...

Kinetic study of microwave-assisted alkaline hydrolysis of Jatropha curcas oil

Science.gov (United States)

Yusuf, Nur'aini Raman; Kamil, Ruzaimah Nik Mohamad; Yusup, Suzana

2016-11-01

The kinetics of hydrolysis of Jatropha curcas oil under microwave irradation in the presence of alkaline solution was studied. The temperature of 50°C, 65°C and 80°C were studied in the range of optimum condition of 1.75 M catalyst, solvent/oil ratio of (1: 68) and 15 minutes reaction time. The rate constants of oil hydrolysis are corresponding to triglyceride disappearance concentration. The rates of reaction for fatty acids production was determined by pseudo first order. The activation energy (Ea) achieved at 30.61 kJ/mol is lower using conventional method. This conclude that the rate of reaction via microwave heating is less temperature sensitive therefore reaction can be obtained at lower temperature.

Eggshells – assisted hydrolysis of banana pulp for biogas production

African Journals Online (AJOL)

KARAKANA

In this study, pretreatment of banana pulp using eggshells in both calcined and un-calcined forms to examine the ... Key words: Anaerobic digestion, banana pulp hydrolysis biogas, eggshells. .... obtain fine powder. ..... using pig waste and cassava peels. ... from bioethanol waste: the effect of pH and urea addition to biogas.

Thermally-assisted Magma Emplacement Explains Restless Calderas

Science.gov (United States)

Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

2017-12-01

Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

Effect of organic molecules on hydrolysis of peptide bond: A DFT study

International Nuclear Information System (INIS)

Makshakova, Olga; Ermakova, Elena

2013-01-01

Highlights: ► DFT study of the effects of small organic molecules on the hydrolysis reactions of peptide bonds. ► Organic molecules can activate nonenzymatic hydrolysis reaction. ► Influence of organic acids on activation energy barrier correlates with their electronegativity. - Abstract: The activation and inhibition effects of small organic molecules on peptide hydrolysis have been studied using a model compound dialanine and DFT approach. Solvent-assisted and non-assisted concerted mechanisms were analyzed. Several transition states for the systems: alanine dipeptide–water molecule in complexes with alcohol molecules, acetonitrile, dimethylsulfoxide, propionic, lactic and pyruvic acids and water molecules were localized. The formation of hydrogen bonds between dipeptide, reactive water molecule and molecules of solvents influences the activation energy barrier of the peptide bond hydrolytic reaction. Strong effect of organic acids on the activation energy barrier correlates with their electronegativity. Acetonitrile can act as an inhibitor of reaction. Mechanisms of regulation of the activation energy barrier are discussed in the terms of donor-acceptor interactions

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Science.gov (United States)

Vanderfleet, Oriana M.; Osorio, Daniel A.; Cranston, Emily D.

2017-12-01

Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238-475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes `design rules' for CNCs with improved size uniformity and charge density. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

Effect of high hydrostatic pressure on the enzymatic hydrolysis of bovine serum albumin.

Science.gov (United States)

De Maria, Serena; Ferrari, Giovanna; Maresca, Paola

2017-08-01

The extent of enzymatic proteolysis mainly depends on accessibility of the peptide bonds, which stabilize the protein structure. The high hydrostatic pressure (HHP) process is able to induce, at certain operating conditions, protein displacement, thus suggesting that this technology can be used to modify protein resistance to the enzymatic attack. This work aims at investigating the mechanism of enzymatic hydrolysis assisted by HHP performed under different processing conditions (pressure level, treatment time). Bovine serum albumin was selected for the experiments, solubilized in sodium phosphate buffer (25 mg mL -1 , pH 7.5) with α-chymotrypsin or trypsin (E/S ratio = 1/10) and HPP treatment (100-500 MPa, 15-25 min). HHP treatment enhanced the extent of the hydrolysis reaction of globular proteins, being more effective than conventional hydrolysis. At HHP treatment conditions maximizing the protein unfolding, the hydrolysis degree of proteins was increased as a consequence of the increased exposure of peptide bonds to the attack of proteolytic enzymes. The maximum hydrolysis degree (10% and 7% respectively for the samples hydrolyzed with α-chymotrypsin and trypsin) was observed for the samples processed at 400 MPa for 25 min. At pressure levels higher than 400 MPa the formation of aggregates was likely to occur; thus the degree of hydrolysis decreased. Protein unfolding represents the key factor controlling the efficiency of HHP-assisted hydrolysis treatments. The peptide produced under high pressure showed lower dimensions and a different structure with respect to those of the hydrolysates obtained when the hydrolysis was carried out at atmospheric pressure, thus opening new frontiers of application in food science and nutrition. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Influence of thermal hydrolysis and inorganic medium on the alcohol yield from tubers of Jerusalem artichoke

Energy Technology Data Exchange (ETDEWEB)

Wlodarczyk, Z; Backman, B

1961-01-01

The thermal hydrolysis of Helianthus tuberosus tubers was performed in a steamer within 30 minutes (the most suitable pressure was 2 atmosphere.). The addition of 225 to 280g (NH/sub 4/)/sub 2/SO/sub 4/ (48 to 60 g N)/100 kg of tubers accelerated the fermentation process of the resulting mash with reference to controls by 5 to 10% on the second day and by 3 to 8% on the third day. (Schizosaccharomyces pombe or Saccharomyces cerevisiae yeasts were used; the temperature was 34/sup 0/, yield of alcohol, 200 l/100 kg of tubers). Addition of 22 to 110 g. P/sub 2/O/sub 5/(as K/sub 2/HPO/sub 4/) did not influence the yield of ethanol.

Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins

NARCIS (Netherlands)

Salazar-Villanea, Sergio; Bruininx, Erik M.A.M.; Gruppen, Harry; Carré, Patrick; Quinsac, Alain; Poel, van der Thomas

2017-01-01

Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00-rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was

Zero field reversal probability in thermally assisted magnetization reversal

Science.gov (United States)

Prasetya, E. B.; Utari; Purnama, B.

2017-11-01

This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

Intensification of delignification and subsequent hydrolysis for the fermentable sugar production from lignocellulosic biomass using ultrasonic irradiation.

Science.gov (United States)

Subhedar, Preeti B; Ray, Pearl; Gogate, Parag R

2018-01-01

The present work deals with intensification of delignification and subsequent enzymatic hydrolysis of sustainable biomass such as groundnut shells, coconut coir and pistachio shells using ultrasound assisted approach so as to develop an economical approach for obtaining bioethanol. Process intensification, in the current context, is referred to as any improvements giving enhanced rates possibly with lower energy and chemical as well as enzyme requirement for delignification and hydrolysis respectively. Conventional processing for both delignification and enzymatic hydrolysis has also been investigated for establishing the degree of intensification. The obtained results for delignification of biomass established that for conventional alkaline treatment, the extent of delignification for the case of groundnut shells, coconut coir and pistachio shells were 41.8, 45.9 and 38% which increased to 71.1, 89.5 and 78.9% respectively giving almost 80-100% increase for the ultrasound assisted approach. Under optimized conditions, the conventional approach resulted in reducing sugar yields as 10.2, 12.1 and 8.1g/L for groundnut shells, coconut coir and pistachio shells respectively whereas for the case of ultrasound-assisted enzymatic hydrolysis, the obtained yields were 21.3, 23.9 and 18.4g/L in same order of biomass. The material samples were characterized by several characterization techniques for establishing the morphological changes obtained due to the use of ultrasound which were found to be favorable for enhanced delignification and hydrolysis for the ultrasound assisted approach. Overall, the results of this work establish the process intensification benefits due to the application of ultrasound for different sustainable biomass with mechanistic understanding based on the morphological analyses. Copyright © 2017 Elsevier B.V. All rights reserved.

Lactose hydrolysis in an enzymatic membrane reactor

Energy Technology Data Exchange (ETDEWEB)

Mertens, B; Huyghebaert, A

1987-10-01

The enzymatic hydrolysis of lactose in whey permeate with subsequent recuperation of Saccharomyces lactis lactase by means of ultrafiltration was investigated. In whey permeate, S. lactis lactase shows maximal activity at pH 6.5; the optimal temperature was found to be 45/sup 0/C and is limited by strong thermal inactivation beyond this temperature. High activity combined with acceptable thermal inactivation (< 10% after 5 h incubation) was established at 30/sup 0/C. S. lactis lactase also displays considerable activity at low temperature (5/sup 0/C). Enzyme stability is reduced drastically by demineralisation: addition of low concentrations of manganese ions (10/sup -3/ M) considerably enhances stability. Using a DDS Lab-Unit 35 fitted with GR61PP polysulphon membranes (cut-off: 20.000), pilot scale experiments were carried out (pH 6.5; 30/sup 0/C) in which whey permeate was hydrolyzed to a degree of hydrolysis of 82% minimum. Enzyme recuperation amounted to 96.5% per batch, all enzyme activity loss being due to thermal inactivation. Microbiological examination of the enzymatic membrane reactor showed that growth of mcicroorganisms can largely be suppressed by working at lower temperature (5/sup 0/C). Eventually, 50 ppm H/sub 2/O/sub 2/ or sterile filtration will adequately solve microbiological problems without affecting enzyme activity.

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

International Nuclear Information System (INIS)

Teodoro, Kelcilene B.R.; Teixeira, Eliangela de Morais; Correa, Ana Carolina; Campos, Adriana de; Marconcini, Jose Manoel; Mattoso, Luiz Henrique Capparelli

2011-01-01

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

Study on the effect of thermal property of metals in ultrasonic-assisted laser machining

International Nuclear Information System (INIS)

Lee, Hu Seung; Kim, Gun Woo; Park, Jong Eun; Cho, Sung Hak; Yang, Min Yang; Park, Jong Kweon

2015-01-01

The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity

Ultrasound assisted synthesis of nanocrystalline zinc oxide: Experiments and modelling

Energy Technology Data Exchange (ETDEWEB)

Hosni, Mongia [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Farhat, Samir, E-mail: farhat@lspm.cnrs.fr [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Schoenstein, Frederic; Karmous, Farah; Jouini, Noureddine [Laboratoire des Sciences des Procédés et des Matériaux, LSPM-CNRS, Université Paris 13, 99 av. J.B. Clément, 93430 Villetaneuse (France); Viana, Bruno [LCMCP Chimie-Paristech, UPMC, Collège de France, 11 Rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Mgaidi, Arbi [Laboratoire de chimie minérale industrielle université Tunis el Manar (Tunisia)

2014-12-05

Highlights: • ZnO nanospheres and nanowires were grown using ultrasound and thermal activation techniques. • The growth uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). • A thermochemical model was developed based on thermodynamic equilibrium calculations. • We estimate species distribution in the bubble in temperature range from 5000 K to ambient. • We propose a new mechanism for ZnO growth assisted by ultrasound irradiation. - Abstract: A fast and green approach is proposed for the preparation of nanocrystalline zinc oxide (ZnO) via ultrasonic (US) irradiation in polyol medium. The process uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). The protocol is compared to thermal activation under the same chemical environment. The activation method is found to be playing a critical role in the selective synthesis of morphologically distinct nanostructures. As compared to thermally activated conventional polyol process, (US) permits to considerably reduce reaction time as well as size of particles. In addition, the shape of these nanoparticles was changed from long nanowires to small nanospheres, indicating different reaction mechanisms. To explain this difference, a thermochemical model was developed based on thermodynamic equilibrium calculations. The model estimate species distribution in the bubble in temperature range from 5000 K to ambient simulating quenching process during bubble formation and collapse. Our results indicate the presence of high density of zinc atoms that could be responsible of a high density of nucleation as compared to thermal activation.

Ultrasound assisted synthesis of nanocrystalline zinc oxide: Experiments and modelling

International Nuclear Information System (INIS)

Hosni, Mongia; Farhat, Samir; Schoenstein, Frederic; Karmous, Farah; Jouini, Noureddine; Viana, Bruno; Mgaidi, Arbi

2014-01-01

Highlights: • ZnO nanospheres and nanowires were grown using ultrasound and thermal activation techniques. • The growth uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). • A thermochemical model was developed based on thermodynamic equilibrium calculations. • We estimate species distribution in the bubble in temperature range from 5000 K to ambient. • We propose a new mechanism for ZnO growth assisted by ultrasound irradiation. - Abstract: A fast and green approach is proposed for the preparation of nanocrystalline zinc oxide (ZnO) via ultrasonic (US) irradiation in polyol medium. The process uses forced hydrolysis of zinc acetate in diethylene glycol (DEG). The protocol is compared to thermal activation under the same chemical environment. The activation method is found to be playing a critical role in the selective synthesis of morphologically distinct nanostructures. As compared to thermally activated conventional polyol process, (US) permits to considerably reduce reaction time as well as size of particles. In addition, the shape of these nanoparticles was changed from long nanowires to small nanospheres, indicating different reaction mechanisms. To explain this difference, a thermochemical model was developed based on thermodynamic equilibrium calculations. The model estimate species distribution in the bubble in temperature range from 5000 K to ambient simulating quenching process during bubble formation and collapse. Our results indicate the presence of high density of zinc atoms that could be responsible of a high density of nucleation as compared to thermal activation

Characteristics of thermally assisted magnetic recording in granular perpendicular media

International Nuclear Information System (INIS)

Shiino, Hirotaka; Kawana, Mayumi; Miyashita, Eiichi; Hayashi, Naoto; Watanabe, Sadayuki

2009-01-01

The effect of thermally assisted magnetic recording using granular perpendicular media with a single-pole-trimmed head has been investigated. A read/write experiment using a spin stand in which the media were heated by laser irradiation demonstrated that the track average amplitude strongly depends on both the position of the write head relative to the center of the laser spot in the down-track direction and on the laser power. Although the signal-to-noise ratio increased with the coercivity of the media, the increment was small; this is thought to be caused by an increase in the switching field distribution of the media with temperature. Our results suggest that the magnetic constant of the media must be optimized with respect to the temperature of writing in order for high-density thermally assisted magnetic recording to be realized

Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose

International Nuclear Information System (INIS)

Gabhane, Jagdish; William, S.P.M. Prince; Vaidya, Atul N.; Das, Sera; Wate, Satish R.

2015-01-01

Highlights: • SAAP is an efficient and economic means of pretreatment. • SAAP was found to be efficient in lignin and hemicellulose removal. • SAAP enhanced the enzymatic hydrolysis. • FTIR, XRD and SEM provided vivid understanding about the mode of action of SAAP. • Mass balance closer of 98% for pretreated GB confirmed the reliability of SAAP. - Abstract: A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment

Starch hydrolysis under low water conditions: a conceptual process design

NARCIS (Netherlands)

Veen, van der M.E.; Veelaert, S.; Goot, van der A.J.; Boom, R.M.

2006-01-01

A process concept is presented for the hydrolysis of starch to glucose in highly concentrated systems. Depending on the moisture content, the process consists of two or three stages. The two-stage process comprises combined thermal and enzymatic liquefaction, followed by enzymatic saccharification.

A simplified kinetic and mass transfer modelling of the thermal hydrolysis of vegetable oils

DEFF Research Database (Denmark)

Forero-Hernandez, Hector Alexander; Jones, Mark Nicholas; Sarup, Bent

2017-01-01

This work presents a combined modelling approach to investigate the kinetics and masstransfer effects on the hydrolysis of vegetable oils under subcritical conditions. The primary purpose of this simplified model is to interpret experimental data collected from typical batch tests and to estimate...... parameters for the proposed model. Due to its heterogeneous nature, the hydrolysis reaction is affected not only by the chemical kinetics but also by the rate of mass transfer between the oil and water as well as their specific contact area in this two phase emulsion. Considering these properties, a model...... and improvement accompanied by Monte Carlo uncertainty analysis. Since the lack of experimental data is a crucial issue in the hydrolysis of vegetable oils, this model-based analysis of data is of substantial value to provide necessary information for detailed modeling and characterization of the process....

Processing of baby food using pressure-assisted thermal sterilization (PATS) and comparison with thermal treatment

Science.gov (United States)

Wang, Yubin; Ismail, Marliya; Farid, Mohammed

2017-10-01

Currently baby food is sterilized using retort processing that gives an extended shelf life. However, this type of heat processing leads to reduction of organoleptic and nutrition value. Alternatively, the combination of pressure and heat could be used to achieve sterilization at reduced temperatures. This study investigates the potential of pressure-assisted thermal sterilization (PATS) technology for baby food sterilization. Here, baby food (apple puree), inoculated with Bacillus subtilis spores was treated using PATS at different operating temperatures, pressures and times and was compared with thermal only treatment. The results revealed that the decimal reduction time of B. subtilis in PATS treatment was lower than that of thermal only treatment. At a similar spore inactivation, the retention of ascorbic acid of PATS-treated sample was higher than that of thermally treated sample. The results indicated that PATS could be a potential technology for baby food processing while minimizing quality deterioration.

Cassava Pulp Hydrolysis under Microwave Irradiation with Oxalic Acid Catalyst for Ethanol Production

Directory of Open Access Journals (Sweden)

Euis Hermiati

2014-07-01

Full Text Available Microwave irradiation is an alternative method of starch hydrolysis that offers a rapid process. The aim of this research was to improve microwave-assisted hydrolysis of cassava pulp by using oxalic acid as a catalyst. Suspension of cassava pulp in 0.5% oxalic acid (1 g/20 mL was subjected to microwave irradiation at 140-230 °C for 5 minutes, with 4 minutes of pre-heating. One gram of fractured activated carbon made of coconut shell was added into a number of suspensions that were subjected to the same conditions of microwave irradiation. The soluble fraction of the hydrolysates was analyzed for its total soluble solids, malto-oligomer distribution, glucose content, pH value, and formation of brown compounds. The effects of the combined severity parameter at a substrate concentration of 5-12.5% on the glucose yield were also evaluated. The highest glucose yield (78% of dry matter was obtained after hydrolysis at 180 °C without activated carbon addition. Heating above 180 °C reduced the glucose yield and increased the pH and the formation of brown compounds. The use of activated carbon in microwave-assisted acid hydrolysis of cassava pulp reduced the glucose yield, but suppressed the formation of brown compounds. The highest glucose yield (70-80% of dry matter was attained at a severity parameter of 1.3-1.5.

Thermal diffusivity of diamond nanowires studied by laser assisted atom probe tomography

Science.gov (United States)

Arnoldi, L.; Spies, M.; Houard, J.; Blum, I.; Etienne, A.; Ismagilov, R.; Obraztsov, A.; Vella, A.

2018-04-01

The thermal properties of single-crystal diamond nanowires (NWs) have been calculated from first principles but have never been measured experimentally. Taking advantage of the sharp geometry of samples analyzed in a laser assisted atom probe, this technique is used to measure the thermal diffusivity of a single NW at low temperature (ab-initio calculations and confirms that thermal diffusivity in nanoscale samples is lower than in bulk samples. The results impact the design and integration of diamond NWs and nanoneedles in nanoscale devices for heat dissipation.

The Solar Thermal Design Assistance Center report of its activities and accomplishments in Fiscal Year 1993

Energy Technology Data Exchange (ETDEWEB)

Menicucci, D.F.

1994-03-01

The Solar Thermal Design Assistance Center (STDAC) at Sandia National Laboratories is a resource provided by the US Department of Energy`s Solar Thermal Program. Its major objectives are to accelerate the use of solar thermal systems through (a) direct technical assistance to users, (b) cooperative test, evaluation, and development efforts with private industry, and (c) educational outreach activities. This report outlines the major activities and accomplishments of the STDAC in Fiscal Year 1993. The report also contains a comprehensive list of persons who contacted the STDAC by telephone for information or technical consulting.

Template free fabrication of hollow hematite spheres via a one-pot polyoxometalate-assisted hydrolysis process

International Nuclear Information System (INIS)

Mao Baodong; Kang Zhenhui; Wang Enbo; Tian Chungui; Zhang Zhiming; Wang Chunlei; Song Yanli; Li Meiye

2007-01-01

Uniform hollow hematite (α-Fe 2 O 3 ) spheres with diameter of about 600-700 nm and shell thickness lower than 100 nm are obtained by direct hydrothermal treatment of dilute FeCl 3 and tungstophosphoric acid H 3 PW 12 O 40 solution at 180 deg. C. The hollow spheres are composed of robust shells with small nanoparticles standing out of the surface and present a high-surface area and a weak ferromagnetic behavior at room temperature. The effect of concentration of H 3 PW 12 O 40 , reaction time and temperature for the formation of the hollow spheres are investigated in series of experiments. The formation of the hollow spheres may be ascribed to a polyoxometalte-assisted forced hydrolysis and dissolution process. - Graphical abstract: Uniform hollow hematite (α-Fe 2 O 3 ) spheres with diameter of about 600-700 nm and shell thickness lower than 100 nm are obtained by direct hydrothermal treatment of dilute FeCl 3 and tungstophosphoric acid H 3 PW 12 O 40 solution at 180 deg. C. The hollow spheres present a high surface area and weak ferromagnetic behavior at room temperature

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

Science.gov (United States)

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Effective of Microwave-KOH Pretreatment on Enzymatic Hydrolysis of Bamboo

Science.gov (United States)

Zhiqiang Li; Zehui Jiang; Yan Yu; Zhiyong Cai

2012-01-01

Bamboo, with its advantages of fast growth, short renovation, easy propagation and rich in cellulose and hemicellulose, is a potential feedstock for bioethanol or other biofuels production. The objective of this study was to examine the fea- sibility of microwave assistant KOH pretreatments to enhance enzymatic hydrolysis of bamboo. Pretreatment was car- ried out by...

Seafood-like flavour obtained from the enzymatic hydrolysis of the protein by-products of seaweed (Gracilaria sp.).

Science.gov (United States)

Laohakunjit, Natta; Selamassakul, Orrapun; Kerdchoechuen, Orapin

2014-09-01

An enzymatic bromelain seaweed protein hydrolysate (eb-SWPH) was characterised as the precursor for thermally processed seafood flavour. Seaweed (Gracilaria fisheri) protein after agar extraction was hydrolysed using bromelain (enzyme activity=119,325 U/g) at 0-20% (w/w) for 0.5-24 h. Optimal hydrolysis conditions were determined using response surface methodology. The proposed model took into account the interaction effect of the enzyme concentration and hydrolysis time on the physicochemical properties and volatile components of eb-SWPH. The optimal hydrolysis conditions for the production of eb-SWPH were 10% bromelain for 3h, which resulted in a 38.15% yield and a 62.91% degree of hydrolysis value. Three free amino acids, arginine, lysine, and leucine, were abundant in the best hydrolysate. Ten volatile flavours of the best eb-SWPH were identified using gas chromatography/mass spectrometry. The predominant odourants were hexanal, hexanoic acid, nonanoic acid, and dihydroactinidiolide. The thermally processed seafood flavour produced from eb-SWPH exhibited a roasted seafood-like flavouring. Copyright © 2014 Elsevier Ltd. All rights reserved.

Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation.

Science.gov (United States)

Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao

2016-09-07

The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

Coal Fly Ash Ceramics: Preparation, Characterization, and Use in the Hydrolysis of Sucrose

Directory of Open Access Journals (Sweden)

Ricardo Pires dos Santos

2014-01-01

Full Text Available Coal ash is a byproduct of mineral coal combustion in thermal power plants. This residue is responsible for many environmental problems because it pollutes soil, water, and air. Thus, it is important to find ways to reuse it. In this study, coal fly ash, obtained from the Presidente Médici Thermal Power Plant, was utilized in the preparation of ceramic supports for the immobilization of the enzyme invertase and subsequent hydrolysis of sucrose. Coal fly ash supports were prepared at several compaction pressures (63.66–318.30 MPa and sintered at 1200°C for 4 h. Mineralogical composition (by X-ray diffraction and surface area were studied. The ceramic prepared with 318.30 MPa presented the highest surface area (35 m2/g and amount of immobilized enzyme per g of support (76.6 mg/g. In assays involving sucrose inversion, it showed a high degree of hydrolysis (around 81% even after nine reuses and 30 days’ storage. Therefore, coal fly ash ceramics were demonstrated to be a promising biotechnological alternative as an immobilization support for the hydrolysis of sucrose.

Experimental investigation on the thermal performance of heat pipe-assisted phase change material based battery thermal management system

International Nuclear Information System (INIS)

Wu, Weixiong; Yang, Xiaoqing; Zhang, Guoqing; Chen, Kai; Wang, Shuangfeng

2017-01-01

Highlights: • A heat pipe assisted phase change material based battery thermal management system is proposed. • The proposed system is compact and efficient from a view of practical application. • Cycling conditions are experimentally simulated for practical working environment. • The proposed system presents better thermal performance in comparison to other systems. • Combining forced air convection with heat pipe further enhances the cooling effect. - Abstract: In this paper, a heat pipe-assisted phase change material (PCM) based battery thermal management (BTM) system is designed to fulfill the comprehensive energy utilization for electric vehicles and hybrid electric vehicles. Combining the large heat storage capacity of the PCM with the excellent cooling effect of heat pipe, the as-constructed heat pipe-assisted PCM based BTM is feasible and effective with a relatively longer operation time and more suitable temperature. The experimental results show that the temperature maldistribution of battery module can be influenced by heat pipes when they are activated under high discharge rates of the batteries. Moreover, with forced air convection, the highest temperature could be controlled below 50 °C even under the highest discharge rate of 5C and a more stable and lower temperature fluctuation is obtained under cycling conditions. Meanwhile, the effectiveness of further increasing air velocity (i.e., more fan power consumption) is limited when the highest temperature continues to reduce at a lower rate due to the phase transition process of PCM. These results are expected to provide insights into the design and optimization of BTM systems.

Review and summary of Solar Thermal Conversion Program planning assistance

Energy Technology Data Exchange (ETDEWEB)

1975-06-01

The Solar Thermal Conversion Program comprises a major part of the national solar energy program which must be continuously reviewed and modified where necessary. Modifications are typically required to reflect technical achievements and uncertainties which arise from within the program or from other technical programs, changes in budgets available for supporting the program as well as internal program funding priorities, changing goals such as through acceleration or stretch-out of the program schedule, significant organizational changes involving responsible governmental agencies, the introduction of new project management support contractors, and required budget or schedule changes occurring within individual projects that make up the Solar Thermal Conversion Program. The Aerospace Corporation has provided data to assist in planning, review, coordination, and documentation of the overall Solar Thermal Conversion Program. The Solar Thermal Conversion Program Plan is described in detail. Sections 2.0 through 5.0 cover the discussion and detail planning covering the objectives, justification, basic and alternative plans, budgets, and schedules for the Solar Thermal sub-unit portion of the Solar Electric Applications effort. Appendices B1, B2, and B3 include the March 21, March 28, and April 5, 1975, Program Plan submissions of the complete Solar Electric Applications effort. In Appendix B the Solar Thermal, Solar Photovoltaic, Wind Energy, and Ocean Thermal sub-unit texts have been condensed and formatted for integration in the overall ERDA budget package. (WHK)

Understanding oscillatory phenomena in molecular hydrogen generation via sodium borohydride hydrolysis.

Science.gov (United States)

Budroni, M A; Biosa, E; Garroni, S; Mulas, G R C; Marchettini, N; Culeddu, N; Rustici, M

2013-11-14

The hydrolysis of borohydride salts represents one of the most promising processes for the generation of high purity molecular hydrogen under mild conditions. In this work we show that the sodium borohydride hydrolysis exhibits a fingerprinting periodic oscillatory transient in the hydrogen flow over a wide range of experimental conditions. We disproved the possibility that flow oscillations are driven by supersaturation phenomena of gaseous bubbles in the reactive mixture or by a nonlinear thermal feedback according to a thermokinetic model. Our experimental results indicate that the NaBH4 hydrolysis is a spontaneous inorganic oscillator, in which the hydrogen flow oscillations are coupled to an "oscillophor" in the reactive solution. The discovery of this original oscillator paves the way for a new class of chemical oscillators, with fundamental implications not only for testing the general theory on oscillations, but also with a view to chemical control of borohydride systems used as a source of hydrogen based green fuel.

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

Science.gov (United States)

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. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Thermal effects on transducer material for heat assisted magnetic recording application

Energy Technology Data Exchange (ETDEWEB)

Ji, Rong, E-mail: Ji-Rong@dsi.a-star.edu.sg; Xu, Baoxi; Cen, Zhanhong; Ying, Ji Feng; Toh, Yeow Teck [Data Storage Institute, Agency for Science, Technology and Research (A-STAR), 5 Engineering Drive 1, Singapore 117608 (Singapore)

2015-05-07

Heat Assisted Magnetic Recording (HAMR) is a promising technology for next generation hard disk drives with significantly increased data recording capacities. In HAMR, an optical near-field transducer (NFT) is used to concentrate laser energy on a magnetic recording medium to fulfill the heat assist function. The key components of a NFT are transducer material, cladding material, and adhesion material between the cladding and the transducer materials. Since transducer materials and cladding materials have been widely reported, this paper focuses on the adhesion materials between the Au transducer and the Al{sub 2}O{sub 3} cladding material. A comparative study for two kinds of adhesion material, Ta and Cr, has been conducted. We found that Ta provides better thermal stability to the whole transducer than Cr. This is because after thermal annealing, chromium forms oxide material at interfaces and chromium atoms diffuse remarkably into the Au layer and react with Au to form Au alloy. This study also provides insights on the selection of adhesion material for HAMR transducer.

Lipase applications in oil hydrolysis with a case study on castor oil: a review.

Science.gov (United States)

Goswami, Debajyoti; Basu, Jayanta Kumar; De, Sirshendu

2013-03-01

Lipase (triacylglycerol acylhydrolase) is a unique enzyme which can catalyze various types of reactions such as hydrolysis, esterification, alcoholysis etc. In particular, hydrolysis of vegetable oil with lipase as a catalyst is widely studied. Free lipase, lipase immobilized on suitable support, lipase encapsulated in a reverse micelle and lipase immobilized on a suitable membrane to be used in membrane reactor are the most common ways of employing lipase in oil hydrolysis. Castor oil is a unique vegetable oil as it contains high amounts (90%) of a hydroxy monounsaturated fatty acid named ricinoleic acid. This industrially important acid can be obtained by hydrolysis of castor oil. Different conventional hydrolysis processes have certain disadvantages which can be avoided by a lipase-catalyzed process. The degree of hydrolysis varies widely for different lipases depending on the operating range of process variables such as temperature, pH and enzyme loading. Immobilization of lipase on a suitable support can enhance hydrolysis by suppressing thermal inactivation and estolide formation. The presence of metal ions also affects lipase-catalyzed hydrolysis of castor oil. Even a particular ion has different effects on the activity of different lipases. Hydrophobic organic solvents perform better than hydrophilic solvents during the reaction. Sonication considerably increases hydrolysis in case of lipolase. The effects of additives on the same lipase vary with their types. Nonionic surfactants enhance hydrolysis whereas cationic and anionic surfactants decrease it. A single variable optimization method is used to obtain optimum conditions. In order to eliminate its disadvantages, a statistical optimization method is used in recent studies. Statistical optimization shows that interactions between any two of the following pH, enzyme concentration and buffer concentration become significant in presence of a nonionic surfactant named Span 80.

Ultrasound assisted enzymatic hydrolysis for isolating titanium dioxide nanoparticles from bivalve mollusk before sp-ICP-MS.

Science.gov (United States)

Taboada-López, María Vanesa; Iglesias-López, Sara; Herbello-Hermelo, Paloma; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2018-08-14

Applicability of single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) using dwell times equal to or shorter than 100 μs has been tested for assessing titanium dioxide nanoparticles (TiO 2 NPs) in bivalve mollusks. TiO 2 NPs isolation from fresh mollusk tissues was achieved by ultrasound assisted enzymatic hydrolysis procedure using a pancreatin/lipase mixture. Optimum extraction conditions imply ultrasonication (60% amplitude) for 10 min, and 7.5 mL of a solution containing 3.0 g L -1 of pancreatin and lipase (pH 7.4). The developed method was found to be repeatable (repeatability of 17% for the over-all procedure, TiO 2 NPs concentration of 5.33 × 10 7  ± 8.89 × 10 6 , n = 11), showing a limit of detection of 5.28 × 10 6 NPs g -1 , and a limit of detection in size of 24.4-30.4 nm, based on the 3σ criteria, and on the 3σ/5 σ criteria, respectively. The analytical recovery within the 90-99% range (use of TiO 2 NPs standards of 50 nm at 7 and 14 μg L -1 as Ti). Several bivalve mollusks (clams, cockles, mussels, razor clams, oysters and variegated scallops) were analyzed for total titanium (ICP-MS after microwave assisted acid digestion), and for TiO 2 NPs by the proposed method. TiO 2 NPs concentrations were within the 2.36 × 10 7 -1.25 × 10 8 NPs g -1 range, and the most frequent sizes were from 50 to 70 nm. Copyright © 2018 Elsevier B.V. All rights reserved.

Thermal damage control of dye-assisted laser tissue welding: effect of dye concentration

Science.gov (United States)

Xie, Hua; Buckley, Lisa A.; Prahl, Scott A.; Shaffer, Brian S.; Gregory, Kenton W.

2001-05-01

Successful laser-assisted tissue welding was implemented to provide proper weld strength with minimized tissue thermal injury. We investigated and compared the weld strengths and morphologic changes in porcine small intestinal submucose (SIS) and porcine ureteral tissues with various concentration of indocyanine green (ICG) and with a solid albumin sheet. The study showed that the tissues were welded at lower ICG concentration (0.05 mM) with minimized tissue thermal damage using an 800-nm wavelength diode laser.

Technical assistance for development of thermally conductive nitride filler for epoxy molding compounds

Energy Technology Data Exchange (ETDEWEB)

Ryu, Ho Jin; Song, Kee Chan; Jung, In Ha

2005-07-15

Technical assistance was carried out to develop nitride filler for thermally conductive epoxy molding compounds. Carbothermal reduction method was used to fabricate silicon nitride powder from mixtures of silica and graphite powders. Microstructure and crystal structure were observed by using scanning electron microscopy and x-ray diffraction technique. Thermal properties of epoxy molding compounds containing silicon nitride were measured by using laser flash method. Fabrication process of silicon nitride nanowire was developed and was applied to a patent.

Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio.

Science.gov (United States)

Cuadrado, Carmen; Cheng, Hsiaopo; Sanchiz, Africa; Ballesteros, Isabel; Easson, Michael; Grimm, Casey C; Dieguez, M Carmen; Linacero, Rosario; Burbano, Carmen; Maleki, Soheila J

2018-02-15

Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of the carbon isotopic composition of whole/intact biological specimens using at-line direct thermal desorption to effect thermally assisted hydrolysis/methylation

NARCIS (Netherlands)

Akoto, L.; Vreuls, R.J.J.; Irth, H.; Floris, V.; Hoogveld, H.L.; Pel, R.

2008-01-01

In this paper, we discuss the use of a direct thermal desorption (DTD) interface as an alternative to Curie-point flash pyrolysis system as an inlet technique in gas chromatography–combustion isotope-ratio mass spectrometry (GC/C-IRMS) analysis of whole/intact phytoplankton and zooplankton

Progressing batch hydrolysis process

Science.gov (United States)

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.

Tissue-specific biomass recalcitrance in corn stover pretreated with liquid hot-water: enzymatic hydrolysis (part 1).

Science.gov (United States)

Zeng, Meijuan; Ximenes, Eduardo; Ladisch, Michael R; Mosier, Nathan S; Vermerris, Wilfred; Huang, Chia-Ping; Sherman, Debra M

2012-02-01

Lignin content, composition, distribution as well as cell wall thickness, structures, and type of tissue have a measurable effect on enzymatic hydrolysis of cellulose in lignocellulosic feedstocks. The first part of our work combined compositional analysis, pretreatment and enzyme hydrolysis for fractionated pith, rind, and leaf tissues from a hybrid stay-green corn, in order to identify the role of structural characteristics on enzyme hydrolysis of cell walls. The extent of enzyme hydrolysis follows the sequence rind cellulose to glucose in 24 h in the best cases. Physical fractionation of corn stalks or other C(4) grasses into soft and hard tissue types could reduce cost of cellulose conversion by enabling reduced enzyme loadings to hydrolyze soft tissue, and directing the hard tissue to other uses such as thermal processing, combustion, or recycle to the land from which the corn was harvested. Copyright © 2011 Wiley Periodicals, Inc.

Improvements on enzymatic hydrolysis of human hair for illicit drug determination by gas chromatography/mass spectrometry.

Science.gov (United States)

Míguez-Framil, Martha; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar; López, Patricia; Tabernero, María Jesús; Bermejo, Ana María

2007-11-15

The use of ultrasound energy for accelerating the pronase E enzymatic hydrolysis of human hair for extracting illicit drugs has been novelty tested. The enzymatic extracts obtained after 30 min of sonication in an ultrasonic water bath were subjected to an optimized solid-phase extraction process, which involved a solution of 2.0% (v/v) acetic acid in methanol as eluting solution and concentration by N2 stream evaporation. A gas chromatography/mass spectrometry method was used to separate and determine cocaine, benzoylecgonine, codeine, morphine, and 6-monoacethylmorphine in 20 min. Variables affecting ultrasound-assisted pronase E hydrolysis such as hydrolysis temperature, hydrolysis time, enzyme concentration, catalyzer (1,4-dithiothreitol) concentration, ionic strength, pH, and ultrasound frequency were simultaneously evaluated by a Plackett-Burman design 2(8) PBD of resolution III. The most statistically significant variables were ionic strength and pH, which means that analyte extraction is mainly attributed to pronase E activity. The optimization or evaluation of all the factors has led to an accelerated pronase E hydrolysis of human hair, which can be completed in 30 min. Results have been found to be statistically similar to those obtained with conventional pronase E hydrolysis. The accelerated method was finally applied to several human hair samples from multidrug abusers.

Microwave-Assisted Hydrolysis of Chitosan from Shrimp Shell Waste for Glucosammine Hydrochlorid Production

International Nuclear Information System (INIS)

Zaeni, Ahmad; Safitri, Endang; Fuadah, Badrotul; Sudiana, I Nyoman

2017-01-01

Chitin is the most widespread renewable natural sources following cellulose as the main source of chitosan. Chitin is isolated from crustacean waste and shrimp shells. Chitosan is derived from chitin throuhgt demineralisation, deproteination, decolorisation and deacetylation process using chemicals such as sodium hydroxide, hydrogen chloride and acetone. Glucosamine hydrochloride (GlcN-Cl) can be produced by hydrolysis of chitosan by using hydrogen chloride. During deacetylation and hydrolysis the solution is heated by hotplate or furnace. In this paper we use microwave instead of hotplate for production chitosan and GlcN-Cl. The research investigates effect of microwaves to amount of rendemen and their property. The chitosan was characterized its moisture content, solubility, and degree of deacetylation (DDA). Whereas the glucosammine hydrochloride characterized its functional groups using FTIR and crystallization by using X-Ray Difraction (XRD). The experimental results show that the use of microwave energy on deacetilation of chitosan and hydrolisis processes can decrease time consuming and reactant concentration during production. the DDA value obtained was very high from 70 to 85%. The results also show that microwaves meet chitosan and GlcN-Cl standards. (paper)

Microwave-Assisted Hydrolysis of Chitosan from Shrimp Shell Waste for Glucosammine Hydrochlorid Production

Science.gov (United States)

Zaeni, Ahmad; Safitri, Endang; Fuadah, Badrotul; Nyoman Sudiana, I.

2017-05-01

Chitin is the most widespread renewable natural sources following cellulose as the main source of chitosan. Chitin is isolated from crustacean waste and shrimp shells. Chitosan is derived from chitin throuhgt demineralisation, deproteination, decolorisation and deacetylation process using chemicals such as sodium hydroxide, hydrogen chloride and acetone. Glucosamine hydrochloride (GlcN-Cl) can be produced by hydrolysis of chitosan by using hydrogen chloride. During deacetylation and hydrolysis the solution is heated by hotplate or furnace. In this paper we use microwave instead of hotplate for production chitosan and GlcN-Cl. The research investigates effect of microwaves to amount of rendemen and their property. The chitosan was characterized its moisture content, solubility, and degree of deacetylation (DDA). Whereas the glucosammine hydrochloride characterized its functional groups using FTIR and crystallization by using X-Ray Difraction (XRD). The experimental results show that the use of microwave energy on deacetilation of chitosan and hydrolisis processes can decrease time consuming and reactant concentration during production. the DDA value obtained was very high from 70 to 85%. The results also show that microwaves meet chitosan and GlcN-Cl standards.

Preparation of micro-fibrillated cellulose based on sugar palm ijuk (Arenga pinnata) fibres through partial acid hydrolysis

Science.gov (United States)

Saputro, A.; Verawati, I.; Ramahdita, G.; Chalid, M.

2017-07-01

The aim of this study was to isolate and characterized micro-fibrillated cellulose (MFC) from sugar palm/ijuk fibre (Arenga pinnata) by partial sulfuric acid hydrolysis. Cellulose fibre was prepared by repeated treatments with 5 wt% sodium hydroxide 2 h at 80°C, followed by bleaching with 1.7 wt% sodium chlorite for 2 h at 80°C in acidic environment under stirring. MFC was prepared by partial hydrolysis with sulfuric acid in various concentrations (30, 40, 50, and 60 % for 45 min at 45 °C) under stirring. Fourier Transform Infrared, Field Emission Scanning Electron Microscope, Thermo Gravimetric Analyzer and X-ray Diffraction characterized cellulose fibre and MFC. FTIR measurements showed that alkaline and bleaching treatments were effective to remove non-cellulosic constituents such as wax, lignin and hemicellulose. FESEM observation revealed conversion into more clear surface and defibrillation of cellulosic fibre after pre-treatments. XRD measurement revealed increase in crystallinity after pre-treatments and acid hydrolysis from 54.4 to 87.8%. Thermal analysis showed that increasing acid concentration reduced thermal stability.

Analysis of self-heating of thermally assisted spin-transfer torque magnetic random access memory

Directory of Open Access Journals (Sweden)

Austin Deschenes

2016-11-01

Full Text Available Thermal assistance has been shown to significantly reduce the required operation power for spin torque transfer magnetic random access memory (STT-MRAM. Proposed heating methods include modified material stack compositions that result in increased self-heating or external heat sources. In this work we analyze the self-heating process of a standard perpendicular magnetic anisotropy STT-MRAM device through numerical simulations in order to understand the relative contributions of Joule, thermoelectric Peltier and Thomson, and tunneling junction heating. A 2D rotationally symmetric numerical model is used to solve the coupled electro-thermal equations including thermoelectric effects and heat absorbed or released at the tunneling junction. We compare self-heating for different common passivation materials, positive and negative electrical current polarity, and different device thermal anchoring and boundaries resistance configurations. The variations considered are found to result in significant differences in maximum temperatures reached. Average increases of 3 K, 10 K, and 100 K for different passivation materials, positive and negative polarity, and different thermal anchoring configurations, respectively, are observed. The highest temperatures, up to 424 K, are obtained for silicon dioxide as the passivation material, positive polarity, and low thermal anchoring with thermal boundary resistance configurations. Interestingly it is also found that due to the tunneling heat, Peltier effect, device geometry, and numerous interfacial layers around the magnetic tunnel junction (MTJ, most of the heat is dissipated on the lower potential side of the magnetic junction. This asymmetry in heating, which has also been observed experimentally, is important as thermally assisted switching requires heating of the free layer specifically and this will be significantly different for the two polarity operations, set and reset.

Chemical failure modes of AlQ3-based OLEDs: AlQ3 hydrolysis.

Science.gov (United States)

Knox, John E; Halls, Mathew D; Hratchian, Hrant P; Schlegel, H Bernhard

2006-03-28

Tris(8-hydroxyquinoline)aluminum(III), AlQ3, is used in organic light-emitting diodes (OLEDs) as an electron-transport material and emitting layer. The reaction of AlQ3 with trace H2O has been implicated as a major failure pathway for AlQ3-based OLEDs. Hybrid density functional calculations have been carried out to characterize the hydrolysis of AlQ3. The thermochemical and atomistic details for this important reaction are reported for both the neutral and oxidized AlQ3/AlQ3+ systems. In support of experimental conclusions, the neutral hydrolysis reaction pathway is found to be a thermally activated process, having a classical barrier height of 24.2 kcal mol(-1). First-principles infrared and electronic absorption spectra are compared to further characterize AlQ3 and the hydrolysis pathway product, AlQ2OH. The activation energy for the cationic AlQ3 hydrolysis pathway is found to be 8.5 kcal mol(-1) lower than for the neutral reaction, which is significant since it suggests a role for charge imbalance in promoting chemical failure modes in OLED devices.

A new estimation of the total flavonoids in silkworm cocoon sericin layer through aglycone determination by hydrolysis-assisted extraction and HPLC-DAD analysis

Directory of Open Access Journals (Sweden)

Jin-Ge Zhao

2016-03-01

Full Text Available Background: Silk sericin and a few non-protein components isolated from the cocoon layer including two silk proteins in silkworm Bombyx mori has many bioactivities. The dietary sericin possess antinatural oxidation, anticancer, antihyperlipidemic, and antidiabetic activities. The non-protein components surrounding the sericin layer involve in wax, pigments mainly meaning flavonoids, sugars, and other impurities. However, very few investigations have reported the estimation of the total flavonoids derived from the cocoon layer. The flavonoids are commonly present in their glycosylated forms and mostly exist as quercetin glycosides in the sericin layers of silkworm cocoons. Objective: The aim of this study was to find a more accurate method to estimate the level of the total flavonoids in silkworm cocoons. Design: An efficient procedure of hydrolysis-assisted extraction (HAE was first established to estimate the level of the total flavonoids through the determination of their aglycones, quercetin, and kaempferol. Then, a comparison was made between traditional colorimetric method and our method. In addition, the antioxidant activities of hydrolysis-assisted extract sample were determined. Results: The average contents of quercetin and kaempferol were 1.98 and 0.42 mg/g in Daizo cocoon. Their recoveries were 99.56 and 99.17%. The total sum of quercetin and kaempferol was detected to be 2.40±0.07 mg/g by HAE-HPLC, while the total flavonoids (2.59±0.48 mg/g estimated by the traditional colorimetric method were only equivalent to 1.28±0.04 mg/g of quercetin. The HAE sample also exhibits that IC50 values of scavenging ability of diphenyl picryl hydrazinyl (DPPH radical and hydroxyl radical (HO· are 243.63 µg/mL and 4.89 mg/mL, respectively. Conclusions: These results show that the HAE-HPLC method is specificity of cocoon and far superior to the colorimetric method. Therefore, this study has profound significance for the comprehensive utilization

Scaling analysis and instantons for thermally assisted tunneling and quantum Monte Carlo simulations

Science.gov (United States)

Jiang, Zhang; Smelyanskiy, Vadim N.; Isakov, Sergei V.; Boixo, Sergio; Mazzola, Guglielmo; Troyer, Matthias; Neven, Hartmut

2017-01-01

We develop an instantonic calculus to derive an analytical expression for the thermally assisted tunneling decay rate of a metastable state in a fully connected quantum spin model. The tunneling decay problem can be mapped onto the Kramers escape problem of a classical random dynamical field. This dynamical field is simulated efficiently by path-integral quantum Monte Carlo (QMC). We show analytically that the exponential scaling with the number of spins of the thermally assisted quantum tunneling rate and the escape rate of the QMC process are identical. We relate this effect to the existence of a dominant instantonic tunneling path. The instanton trajectory is described by nonlinear dynamical mean-field theory equations for a single-site magnetization vector, which we solve exactly. Finally, we derive scaling relations for the "spiky" barrier shape when the spin tunneling and QMC rates scale polynomially with the number of spins N while a purely classical over-the-barrier activation rate scales exponentially with N .

Surfactant-assisted pretreatment and enzymatic hydrolysis of spent mushroom compost for the production of sugars.

Science.gov (United States)

Kapu, N U S; Manning, M; Hurley, T B; Voigt, J; Cosgrove, D J; Romaine, C P

2012-06-01

Spent mushroom compost (SMC), a byproduct of commercial mushroom cultivation, poses serious environmental problems that have hampered the growth of this important agro-industry. In an effort to develop new applications for SMC, we explored its use as a feedstock for bioethanol production. SMC constitutes approximately 30%w/w polysaccharides, 66% of which is glucan. Following dilute-acid pretreatment and enzymatic hydrolysis, both in the presence of PEG 6000, 97% of glucan and 44% of xylan in SMC were converted into the corresponding monosaccharides. Incorporation of PEG 6000 reduced the cellulase requirement by 77%. Zwittergent 3-12 and 3-14 also significantly increased the efficacy of acid pretreatment and enzymatic hydrolysis. The use of SMC in bioethanol production represents a potential mitigation solution for the critical environmental issues associated with the stockpiling of the major byproduct of the mushroom industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

Energy Technology Data Exchange (ETDEWEB)

Cui, Yunkang [Department of Mathematics and Physics, Nanjing Institute of technology, Nanjing, 211167 (China); Chen, Jing, E-mail: chenjingmoon@gmail.com [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong [School of Electronic Science & Engineering, Southeast University, Nanjing, 210096 (China); Zhang, Zichen, E-mail: zz241@ime.ac.cn [Integrated system for Laser applications Group, Institute of Microelectronics of Chinese Academy of Sciences, 100029, Beijing (China)

2017-02-28

Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

Enhanced performance of thermal-assisted electron field emission based on barium oxide nanowire

International Nuclear Information System (INIS)

Cui, Yunkang; Chen, Jing; Zhang, Yuning; Zhang, Xiaobing; Lei, Wei; Di, Yunsong; Zhang, Zichen

2017-01-01

Highlights: • A possible mechanism for thermal-assisted electric field was demonstrated. • A new path for the architecture of the novel nanomaterial and methodology for its potential application in the field emission device area was provided. • The turn-on field, the threshold field and the field emission current density were largely related to the temperature of the cathode. • The relationship between the work function of emitter material and the temperature of emitter was found. - Abstract: In this paper, thermal-assisted field emission properties of barium oxide (BaO) nanowire synthesized by a chemical bath deposition method were investigated. The morphology and composition of BaO nanowire were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SED), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX) respectively. The turn-on field, threshold field and the emission current density could be affected relatively due to the thermal-assisted effect when the electric field was applied, in the meanwhile, the turn-on field for BaO nanowire was measured to be decreased from 1.12 V/μm to 0.66 V/μm when the temperature was raised from 293 K to 593 K, whereas for the threshold field was found to decrease from 3.64 V/μm to 2.12 V/μm. The improved performance was demonstrated due to the reduced work function of the BaO nanowire as the agitation temperature increasing, leading to the higher probability of electrons tunneling through the energy barrier and enhancement of the field emission properties of BaO emitters.

Continuous thermal hydrolysis and anaerobic digestion of sludge. Energy integration study.

Science.gov (United States)

Pérez-Elvira, S I; Fdz-Polanco, F

2012-01-01

Experimental data obtained from the operation in a pilot plant are used to perform mass and energy balances to a global process combining units of thermal hydrolysis (TH) of secondary sludge, anaerobic digestion (AD) of hydrolysed secondary sludge together with fresh primary sludge, and cogeneration from biogas by using a gas engine in which the biogas produces electricity and heat from the exhaust gases. Three scenarios were compared, corresponding to the three digesters operated: C (conventional AD, 17 days residence time), B (combined TH + AD, same time), and A (TH + AD at half residence time). The biogas production of digesters B and A was 33 and 24% better, respectively when compared with C. In the case of the combined TH + AD process (scenarios A and B), the key factors in the energy balance were the recovery of heat from hot streams, and the concentration of sludge. The results of the balances showed that for 8% DS concentration of the secondary sludge tested in the pilot plant, the process can be energetically self-sufficient, but a fraction of the biogas must by-pass the gas engine to be directly burned. From an economic point of view, scenario B is more profitable in terms of green energy and higher waste removal, while scenario A reduces the digester volume required by a half. Considering a population of 100,000 inhabitants, the economic benefit is 87,600 €/yr for scenario A and 132,373 €/yr for B. This value can be increased to 223,867 €/yr by increasing the sludge concentration of the feeding to the TH unit to a minimum value that allows use of all the biogas to produce green energy. This concentration is 13% DS, which is still possible from a practical point of view. Additional benefits gained with the combined TH + AD process are the enhancement of the digesters rheology and the possibility of getting Class A biosolids. The integration study presented here set the basis for the scale-up to a demonstration plant.

Thermal performance analysis of a direct-expansion solar-assisted heat pump water heater

International Nuclear Information System (INIS)

Kong, X.Q.; Zhang, D.; Li, Y.; Yang, Q.M.

2011-01-01

A direct-expansion solar-assisted heat pump water heater (DX-SAHPWH) is described, which can supply hot water for domestic use during the whole year. The system mainly employs a bare flat-plate collector/evaporator with a surface area of 4.2 m 2 , an electrical rotary-type hermetic compressor, a hot water tank with the volume of 150 L and a thermostatic expansion valve. R-22 is used as working fluid in the system. A simulation model based on lumped and distributed parameter approach is developed to predict the thermal performance of the system. Given the structure parameters, meteorological parameters, time step and final water temperature, the numerical model can output operational parameters, such as heat capacity, system COP and collector efficiency. Comparisons between the simulation results and the experimental measurements show that the model is able to give satisfactory predictions. The effect of various parameters, including solar radiation, ambient temperature, wind speed and compressor speed, has been analyzed on the thermal performance of the system. -- Highlights: ► A direct-expansion solar-assisted heat pump water heater (DX-SAHPWH) is described. ► A simulation model based on lumped and distributed parameter approach is developed to predict the thermal performance of the system. ► The numerical model can output operational parameters, such as heat capacity, system COP and collector efficiency. ► Comparisons between the simulation results and the experimental measurements show that the model is able to give satisfactory predictions. ► The effect of various parameters has been analyzed on the thermal performance of the system.

A study of poly(vinyl alcohol thermal degradation by thermogravimetry and differential thermogravimetry

Directory of Open Access Journals (Sweden)

Julián Esteban Barrera

2007-05-01

Full Text Available The thermal degradation of poly(vinyl alcohol (PVA having different degrees of hydrolysis and molecular weights was studied by thermogravimetry (TGA and differential thermogravimetry (DTGA. Four degradation events were identified whose intensity was related to the degree of hydrolysis. It was verified that the solid-state degradation mechanism for high hydrolysis degrees corresponded to eliminating water-forming side groups in stoichiometric amounts. The presence of acetate groups and lower melting points delayed the polymer’s thermal decomposition at lower hydrolysis degrees. There was no direct correlation in these samples between weight-loss during the first degradation event and the stoichiometric quantities which would be produced by eliminating the side groups. Reaction order and energy activation value qualitative coincidence was found by evaluating experimental data by using Freeman-Carroll and Friedman kinetic models.

Ultrasound-assisted degradation of a new bacterial ...

African Journals Online (AJOL)

user

2012-05-14

May 14, 2012 ... polysaccharide composed of rhamnose, glucose, mannose, galactose and glucuronic acid in the molar ... distinguish it from thermal or photochemical degradation ..... hydrolysis with dilute acid cleaves the glycosidic bonds in.

Enzymic lactose hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Miller, J J; Brand, J C

1980-01-01

Acid or enzymic hydrolysis can be used to hydrolyze lactose. Advantages of both are compared and details of enzymic hydrolysis using yeast or fungal enzymes given. The new scheme outlined involves recycling lactase. Because lactose and lactase react to ultrafiltration (UF) membranes differently separation is possible. Milk or milk products are ultrafiltered to separate a concentrate from a lactose-rich permeate which is treated with lactase in a reactor until hydrolysis reaches a required level. The lactase can be removed by UF as it does not permeate the membrane, and it is recycled back to the reactor. Permeate from the second UF stage may or may not be recombined with the concentrate from the first stage to produce a low lactose product (analysis of a typical low-lactose dried whole milk is given). Batch or continuous processes are explained and a batch process without enzyme recovery is discussed. (Refs. 4).

Numerical study of finned heat pipe-assisted thermal energy storage system with high temperature phase change material

International Nuclear Information System (INIS)

Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

2015-01-01

Highlights: • A finned heat pipe-assisted latent heat thermal energy storage system is studied. • The effects of heat pipes spacing and fins geometrical features are investigated. • Smaller heat pipes spacing and longer fins improve the melting rate. • The optimal heat pipe and fin arrangements are determined. - Abstract: In the present study, the thermal characteristics of a finned heat pipe-assisted latent heat thermal energy storage system are investigated numerically. A transient two-dimensional finite volume based model employing enthalpy-porosity technique is implemented to analyze the performance of a thermal energy storage unit with square container and high melting temperature phase change material. The effects of heat pipe spacing, fin length and numbers and the influence of natural convection on the thermal response of the thermal energy storage unit have been studied. The obtained results reveal that the natural convection has considerable effect on the melting process of the phase change material. Increasing the number of heat pipes (decreasing the heat pipe spacing) leads to the increase of melting rate and the decrease of base wall temperature. Also, the increase of fin length results in the decrease of temperature difference within the phase change material in the container, providing more uniform temperature distribution. It was also shown that number of the fins does not have a significant effect on the performance of the system

Kinetics and thermodynamics of the thermal inactivation and chaperone assisted folding of zebrafish dihydrofolate reductase.

Science.gov (United States)

Thapliyal, Charu; Jain, Neha; Rashid, Naira; Chaudhuri Chattopadhyay, Pratima

2018-01-01

The maintenance of thermal stability is a major issue in protein engineering as many proteins tend to form inactive aggregates at higher temperatures. Zebrafish DHFR, an essential protein for the survival of cells, shows irreversible thermal unfolding transition. The protein exhibits complete unfolding and loss of activity at 50 °C as monitored by UV-Visible, fluorescence and far UV-CD spectroscopy. The heat induced inactivation of zDHFR follows first-order kinetics and Arrhenius law. The variation in the value of inactivation rate constant, k with increasing temperatures depicts faster inactivation at elevated temperatures. We have attempted to study the chaperoning ability of a shorter variant of GroEL (minichaperone) and compared it with that of conventional GroEL-GroES chaperone system. Both the chaperone system prevented the aggregation and assisted in refolding of zDHFR. The rate of thermal inactivation was significantly retarded in the presence of chaperones which indicate that it enhances the thermal stability of the enzyme. As minichaperone is less complex, and does not require high energy co-factors like ATP, for its function as compared to conventional GroEL-GroES system, it can act as a very good in vitro as well as in vivo chaperone model for monitoring assisted protein folding phenomenon. Copyright © 2017 Elsevier Inc. All rights reserved.

Two-steps microwave-assisted treatment on acid hydrolysis of sago pith for bioethanol production

Science.gov (United States)

Sunarti, T. C.; Yanti, S. D.; Ruriani, E.

2017-05-01

Sago is a genus of palm that can be utilized to produce fermentable sugars as substrate for bioethanol. Sago pith is a heterogeneous substrate consists of starch and fiber. Acid hydrolysis by microwave heating radiation can break down starch and fibers together in a very short time, so it is considered to be very efficient process. The use of microwave energy (as power level) and variation of heating time can produce fermentable sugar with certain characteristics. This study included the preparation and analysis of sago pith flour; process of acid hydrolysis (0.3 M and 0.5 M H2SO4) using two steps microwave heating, first with power level 30% (1, 2 and 3 min) and second with power level 70% (3 min); and ethanol production. The conventional treatment (autoclaving at 121°C for 15 min) was carried for the comparison. The highest fermentable sugar (105.7 g/l) was resulted from microwave heating with power level 30% for 2 min followed by the power level 70% for 3 min. This hydrolyzate then used as substrate for bioethanol fermentation and partially neutralized (pH 3, 4, 5) by using yeast Issatchenkia orientalis, and the highest ethanol (2.8 g/l) was produced in pH 5.

Effect of gelatinization and hydrolysis conditions on the selectivity of starch hydrolysis with alpha-amylase from Bacillus licheniformis

NARCIS (Netherlands)

Baks, T.; Bruins, M.E.; Matser, A.M.; Janssen, A.E.M.; Boom, R.M.

2008-01-01

Enzymatic hydrolysis of starch can be used to obtain various valuable hydrolyzates with different compositions. The effects of starch pretreatment, enzyme addition point, and hydrolysis conditions on the hydrolyzate composition and reaction rate during wheat starch hydrolysis with ¿-amylase from

Electrospray ionization mass spectrometry for the hydrolysis complexes of cisplatin : Implications for the hydrolysis process of platinum complexes

NARCIS (Netherlands)

Xie, Feifan; Colin, Pieter; Van Bocxlaer, Jan

Non-enzyme-dependent hydrolysis of the drug cisplatin is important for its mode of action and toxicity. However, up until today, the hydrolysis process of cisplatin is still not completely understood. In the present study, the hydrolysis of cisplatin in an aqueous solution was systematically

Effects of microtubule mechanics on hydrolysis and catastrophes

International Nuclear Information System (INIS)

Müller, N; Kierfeld, J

2014-01-01

We introduce a model for microtubule (MT) mechanics containing lateral bonds between dimers in neighboring protofilaments, bending rigidity of dimers, and repulsive interactions between protofilaments modeling steric constraints to investigate the influence of mechanical forces on hydrolysis and catastrophes. We use the allosteric dimer model, where tubulin dimers are characterized by an equilibrium bending angle, which changes from 0 ∘ to 22 ∘ by hydrolysis of a dimer. This also affects the lateral interaction and bending energies and, thus, the mechanical equilibrium state of the MT. As hydrolysis gives rise to conformational changes in dimers, mechanical forces also influence the hydrolysis rates by mechanical energy changes modulating the hydrolysis rate. The interaction via the MT mechanics then gives rise to correlation effects in the hydrolysis dynamics, which have not been taken into account before. Assuming a dominant influence of mechanical energies on hydrolysis rates, we investigate the most probable hydrolysis pathways both for vectorial and random hydrolysis. Investigating the stability with respect to lateral bond rupture, we identify initiation configurations for catastrophes along the hydrolysis pathways and values for a lateral bond rupture force. If we allow for rupturing of lateral bonds between dimers in neighboring protofilaments above this threshold force, our model exhibits avalanche-like catastrophe events. (papers)

Investigating the Plasma-Assisted and Thermal Catalytic Dry Methane Reforming for Syngas Production: Process Design, Simulation and Evaluation

Directory of Open Access Journals (Sweden)

Evangelos Delikonstantis

2017-09-01

Full Text Available The growing surplus of green electricity generated by renewable energy technologies has fueled research towards chemical industry electrification. By adapting power-to-chemical concepts, such as plasma-assisted processes, cheap resources could be converted into fuels and base chemicals. However, the feasibility of those electrified processes at large scale has not been investigated yet. Thus, the current work strives to compare, for first time in the literature, plasma-assisted production of syngas, from CH4 and CO2 (dry methane reforming, with thermal catalytic dry methane reforming. Specifically, both processes are conceptually designed to deliver syngas suitable for methanol synthesis (H2/CO ≥ 2 in mole. The processes are simulated in the Aspen Plus process simulator where different process steps are investigated. Heat integration and equipment cost estimation are performed for the most promising process flow diagrams. Collectively, plasma-assisted dry methane reforming integrated with combined steam/CO2 methane reforming is an effective way to deliver syngas for methanol production. It is more sustainable than combined thermal catalytic dry methane reforming with steam methane reforming, which has also been proposed for syngas production of H2/CO ≥ 2; in the former process, 40% more CO2 is captured, while 38% less H2O is consumed per mol of syngas. Furthermore, the plasma-assisted process is less complex than the thermal catalytic one; it requires higher amount of utilities, but comparable capital investment.

The base catalysed hydrolysis of methyl paraben: a test reaction for flow microcalorimeters used for determination of both kinetic and thermodynamic parameters

Energy Technology Data Exchange (ETDEWEB)

O' Neill, M.A.A.; Beezer, A.E.; Labetoulle, C.; Nicolaides, L.; Mitchell, J.C.; Orchard, J.A.; Connor, J.A.; Kemp, R.B.; Olomolaiye, D

2003-03-24

The results of an inter/intra-laboratory study into a test and reference reaction for isothermal microcalorimeters, the imidazole catalysed hydrolysis of triacetin, have been reported in a recent paper [Thermochim. Acta 380 (2001) 13]. The results and conclusions drawn from this study have been extended to a consideration of the need for a similar test and reference reaction for isothermal microcalorimeters operating in flow mode. This paper reports the findings of a preliminary inter/intra-laboratory study of the base catalysed hydrolysis of methyl 4-hydroxy benzoate (methyl paraben) and its suitability as a test and reference reaction. The derived values for the hydrolysis reaction were (3.15{+-}0.11)x10{sup -4} s{sup -1} and -50.5{+-}4.3 kJ mol{sup -1} for the rate constant and enthalpy, respectively. It is also reported how such a test and reference reaction can be used to validate the thermal output from a LKB 10-700-1 and Thermometric Thermal Activity Monitor (TAM) 2277-202 flow microcalorimeters.

Selective ultrasound-enhanced enzymatic hydrolysis of oleuropein to its aglycon in olive (Olea europaea L.) leaf extracts.

Science.gov (United States)

Delgado-Povedano, María Del Mar; Priego-Capote, Feliciano; Luque de Castro, María Dolores

2017-04-01

Hydrolysis of oleuropein, the main phenol in olive (Olea europaea L.) leaf extracts, to oleuropein aglycon and other subsequent products in the hydrolytic pathway can be catalyzed by different enzymes. Three of the most used hydrolases were assayed to catalyze the process, and β-glucosidase from Aspergillus niger was selected. Acceleration of the enzymatic hydrolysis by ultrasound (US) was studied using a Box-Behnken design (duty cycle, amplitude, cycle time) and an oleuropein standard, and the optimum US conditions for achieving maximum yield of oleuropein aglycon were 0.5s/s duty cycle, 50% amplitude and 45s cycle. The method was applied to obtain oleuropein aglycon from commercial and laboratory extracts from olive leaves, which may have a pharmacological use as deduced by its healthy properties. The kinetics of the US-assisted enzymatic hydrolysis was monitored by analysis of the target compounds using liquid chromatography-tandem mass spectrometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Covalent immobilization of β-glucosidase on magnetic particles for lignocellulose hydrolysis.

Science.gov (United States)

Alftrén, Johan; Hobley, Timothy John

2013-04-01

β-Glucosidase hydrolyzes cellobiose to glucose and is an important enzyme in the consortium used for hydrolysis of cellulosic and lignocellulosic feedstocks. In the present work, β-glucosidase was covalently immobilized on non-porous magnetic particles to enable re-use of the enzyme. It was found that particles activated with cyanuric chloride and polyglutaraldehyde gave the highest bead-related immobilized enzyme activity when tested with p-nitrophenyl-β-D-glucopyranoside (104.7 and 82.2 U/g particles, respectively). Furthermore, the purified β-glucosidase preparation from Megazyme gave higher bead-related enzyme activities compared to Novozym 188 (79.0 and 9.8 U/g particles, respectively). A significant improvement in thermal stability was observed for immobilized enzyme compared to free enzyme; after 5 h (at 65 °C), 36 % of activity remained for the former, while there was no activity in the latter. The performance and recyclability of immobilized β-glucosidase on more complex substrate (pretreated spruce) was also studied. It was shown that adding immobilized β-glucosidase (16 U/g dry matter) to free cellulases (8 FPU/g dry matter) increased the hydrolysis yield of pretreated spruce from ca. 44 % to ca. 65 %. In addition, it was possible to re-use the immobilized β-glucosidase in the spruce and retain activity for at least four cycles. The immobilized enzyme thus shows promise for lignocellulose hydrolysis.

Simulations of planar non-thermal plasma assisted ignition at atmospheric pressure

KAUST Repository

Casey, Tiernan A.

2016-10-21

The opportunity for ignition assistance by a pulsed applied voltage is investigated in a canonical one-dimensional configuration. An incipient ignition kernel, formed by localized energy deposition into a lean mixture of methane and air at atmospheric pressure, is subjected to sub-breakdown electric fields (E/N ≈ 100 Td) by a DC potential applied across the domain, resulting in non-thermal behavior of the plasma formed during the discharge. A two-fluid approach is employed to couple thermal neutrals and ions to the non-thermal electrons. A two-temperature plasma mechanism describing gas phase combustion, excitation of neutral species, and high-energy electron kinetics is employed to account for non-thermal effects. Charged species transported from the ignition zone drift rapidly through the domain, augmenting the magnitude of the electric field in the fresh gas during the pulse through a dynamic-electrode effect, which results in an increase in the energy of the electrons in the fresh mixture with increasing time. Enhanced fuel and oxidizer decomposition due to electron impact dissociation and interaction with excited neutrals generate a pool of radicals, mostly O and H, in the fresh gas ahead of the flame\\'s preheat zone. In the configuration considered, the effect of the nanosecond pulse is to increase the mass of fuel burned at equivalent times relative to the unsupported ignition through enhanced radical generation, resulting in an increased heat release rate in the immediate aftermath of the pulse.

Enzymatic hydrolysis of pretreated soybean straw

International Nuclear Information System (INIS)

Xu Zhong; Wang Qunhui; Jiang Zhaohua; Yang Xuexin; Ji Yongzhen

2007-01-01

In order to produce lactic acid, from agricultural residues such as soybean straw, which is a raw material for biodegradable plastic production, it is necessary to decompose the soybean straw into soluble sugars. Enzymatic hydrolysis is one of the methods in common use, while pretreatment is the effective way to increase the hydrolysis rate. The optimal conditions of pretreatment using ammonia and enzymatic hydrolysis of soybean straw were determined. Compared with the untreated straw, cellulose in straw pretreated by ammonia liquor (10%) soaking for 24 h at room temperature increased 70.27%, whereas hemicellulose and lignin in pretreated straw decreased to 41.45% and 30.16%, respectively. The results of infrared spectra (IR), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis also showed that the structure and the surface of the straw were changed through pretreatment that is in favor of the following enzymatic hydrolysis. maximum enzymatic hydrolysis rate of 51.22% was achieved at a substrate concentration of 5% (w/v) at 50 deg. C and pH 4.8 using cellulase (50 fpu/g of substrate) for 36 h

Evidence for thermally assisted threshold switching behavior in nanoscale phase-change memory cells

International Nuclear Information System (INIS)

Le Gallo, Manuel; Athmanathan, Aravinthan; Krebs, Daniel; Sebastian, Abu

2016-01-01

In spite of decades of research, the details of electrical transport in phase-change materials are still debated. In particular, the so-called threshold switching phenomenon that allows the current density to increase steeply when a sufficiently high voltage is applied is still not well understood, even though there is wide consensus that threshold switching is solely of electronic origin. However, the high thermal efficiency and fast thermal dynamics associated with nanoscale phase-change memory (PCM) devices motivate us to reassess a thermally assisted threshold switching mechanism, at least in these devices. The time/temperature dependence of the threshold switching voltage and current in doped Ge 2 Sb 2 Te 5 nanoscale PCM cells was measured over 6 decades in time at temperatures ranging from 40 °C to 160 °C. We observe a nearly constant threshold switching power across this wide range of operating conditions. We also measured the transient dynamics associated with threshold switching as a function of the applied voltage. By using a field- and temperature-dependent description of the electrical transport combined with a thermal feedback, quantitative agreement with experimental data of the threshold switching dynamics was obtained using realistic physical parameters

Monte Carlo simulation for thermal assisted reversal process of micro-magnetic torus ring with bistable closure domain structure

Energy Technology Data Exchange (ETDEWEB)

Terashima, Kenichi; Suzuki, Kenji; Yamaguchi, Katsuhiko, E-mail: yama@sss.fukushima-u.ac.jp

2016-04-01

Monte Carlo simulations were performed for temperature dependences of closure domain parameter for a magnetic micro-torus ring cluster under magnetic field on limited temperature regions. Simulation results show that magnetic field on tiny limited temperature region can reverse magnetic closure domain structures when the magnetic field is applied at a threshold temperature corresponding to intensity of applied magnetic field. This is one of thermally assisted switching phenomena through a self-organization process. The results show the way to find non-wasteful pairs between intensity of magnetic field and temperature region for reversing closure domain structure by temperature dependence of the fluctuation of closure domain parameter. Monte Carlo method for this simulation is very valuable to optimize the design of thermally assisted switching devices.

Optimization of dynamic-microwave assisted enzymatic hydrolysis extraction of total ginsenosides from stems and leaves of panax ginseng by response surface methodology.

Science.gov (United States)

Wang, Xiao-Yan; Ren, Hui

2018-03-21

Ginseng stems and leaves (GSAL) are abundant in ginsenosides compounds. For efficient utilization of GSAL and the enhancement of total ginsenosides (TG) compound yields in GSAL, TG from GSAL were extracted, using dynamic-microwave assisted extraction coupled with enzymatic hydrolysis (DMAE-EH) method. The extraction process has been simulated and its main influencing factors such as ethanol concentration, microwave temperature, microwave time and pump flow rate have been optimized by response surface methodology coupled with a Box-Behnken design(BBD). The experimental results indicated that optimal extraction conditions of TG from GSAL were as follows: ethanol concentration of 75%, microwave temperature of 60°C, microwave time of 20 min and pump flow rate of 38 r/min. After experimental verification, the experimental yields of TG was 60.62 ± 0.85 mg g -1 , which were well agreement with the predicted by the model. In general, the present results demonstrated that DMAE-EH method was successfully used to extract total ginsenosides in GSAL.

Electrospray ionization mass spectrometry for the hydrolysis complexes of cisplatin: implications for the hydrolysis process of platinum complexes.

Science.gov (United States)

Feifan, Xie; Pieter, Colin; Jan, Van Bocxlaer

2017-07-01

Non-enzyme-dependent hydrolysis of the drug cisplatin is important for its mode of action and toxicity. However, up until today, the hydrolysis process of cisplatin is still not completely understood. In the present study, the hydrolysis of cisplatin in an aqueous solution was systematically investigated by using electrospray ionization mass spectrometry coupled to liquid chromatography. A variety of previously unreported hydrolysis complexes corresponding to monomeric, dimeric and trimeric species were detected and identified. The characteristics of the Pt-containing complexes were investigated by using collision-induced dissociation (CID). The hydrolysis complexes demonstrate distinctive and correlative CID characteristics, which provides tools for an informative identification. The most frequently observed dissociation mechanism was sequential loss of NH 3 , H 2 O and HCl. Loss of the Pt atom was observed as the final step during the CID process. The formation mechanisms of the observed complexes were explored and experimentally examined. The strongly bound dimeric species, which existed in solution, are assumed to be formed from the clustering of the parent compound and its monohydrated or dihydrated complexes. The role of the electrospray process in the formation of some of the observed ions was also evaluated, and the electrospray ionization-related cold clusters were identified. The previously reported hydrolysis equilibria were tested and subsequently refined via a hydrolysis study resulting in a renewed mechanistic equilibrium system of cisplatin as proposed from our results. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Hydrolysis of uranium monocarbide

International Nuclear Information System (INIS)

Hajek, B.; Karen, P.; Brozek, V.

1984-01-01

The substoichiometric uranium monocarbide UCsub(0.95) was hydrolyzed in acid medium at 80 degC. The composition of the products of hydrolysis corresponds to published data but it correlates better with the stoichiometric composition of the hydrolyzable carbide. The mechanisms of the hydrolytic reaction are discussed and a modified radical mechanism is suggested based on the concept of initiation of the radical process by Hsup(.) radicals formed owing to the nonstoichiometry of the substance. A relation is proposed for calculating the content of free hydrogen in the hydrolysis products of carbides of metallic nature for which a radical mechanism of their reaction with water can be assumed. Some effects occurring during the hydrolysis of uranium carbide, as described in literature, are explained in terms of the concept suggested. The results obtained by the authors for carbides of manganese (Mn 7 C 3 ) and for rare earth elements are discussed. (author)

Ultrasound assisted, thermally activated persulfate oxidation of coal tar DNAPLs.

Science.gov (United States)

Peng, Libin; Wang, Li; Hu, Xingting; Wu, Peihui; Wang, Xueqing; Huang, Chumei; Wang, Xiangyang; Deng, Dayi

2016-11-15

The feasibility of ultrasound assisted, thermally activated persulfate for effective oxidation of twenty 2-6 ringed coal tar PAHs in a biphasic tar/water system and a triphasic tar/soil/water system were investigated and established. The results indicate that ultrasonic assistance, persulfate and elevated reaction temperature are all required to achieve effective oxidation of coal tar PAHs, while the heating needed can be provided by ultrasonic induced heating as well. Further kinetic analysis reveals that the oxidation of individual PAH in the biphasic tar/water system follows the first-order kinetics, and individual PAH oxidation rate is primary determined by the mass transfer coefficients, tar/water interfacial areas, the aqueous solubility of individual PAH and its concentration in coal tar. Based on the kinetic analysis and experimental results, the contributions of ultrasound, persulfate and elevated reaction temperature to PAHs oxidation were characterized, and the effects of ultrasonic intensity and oxidant dosage on PAHs oxidation efficiency were investigated. In addition, the results indicate that individual PAH degradability is closely related to its reactivity as well, and the high reactivity of 4-6 ringed PAHs substantially improves their degradability. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrolytic gain during hydrolysis reactions : implications and correction procedures

NARCIS (Netherlands)

Marchal, L.M.; Tramper, J.

1999-01-01

Some of the structural parameters of starch (e.g. % beta- or gluco-hydrolysis) were influenced by the increase in mass during the hydrolysis reactions (hydrolytic gain). Procedures were derived to correct this apparent % of hydrolysis to actual % of hydrolysis. These analytically derived equations

Enhanced cellulase hydrolysis of eucalyptus waste fibers from pulp mill by Tween80-assisted ferric chloride pretreatment.

Science.gov (United States)

Chen, Liheng; Fu, Shiyu

2013-04-03

Pretreatment combining FeCl3 and Tween80 was performed for cellulose-to-ethanol conversion of eucalyptus alkaline peroxide mechanical pulping waste fibers (EAWFs). The FeCl3 pretreatment alone showed a good effect on the enzymatic hydrolysis of EAWFs, but inhibited enzyme activity to some extent. A surfactant, Tween80, added during FeCl3 pretreatment was shown to significantly enhance enzyme reaction by eluting enzymatic inhibitors such as iron(III) that are present at the surface of the pretreated biomass. Treatment temperature, liquid-solid ratio, treatment time, FeCl3 concentration, and Tween80 dosage for pretreatment were optimized as follows: 180 °C, 8:1, 30 min, 0.15 mol/L, and 1% (w/v). Pretreated EAWFs under such optimal conditions provided enzymatic glucose (based on 100 g of oven-dried feedstock) and substrate enzymatic digestibility of EAWFs of 34.8 g and 91.3% after 72 h of enzymatic hydrolysis, respectively, with an initial cellulase loading of 20 FPU/g substrate.

Thermally assisted nanosecond laser generation of ferric nanoparticles

Science.gov (United States)

Kurselis, K.; Kozheshkurt, V.; Kiyan, R.; Chichkov, B.; Sajti, L.

2018-03-01

A technique to increase nanosecond laser based production of ferric nanoparticles by elevating temperature of the iron target and controlling its surface exposure to oxygen is reported. High power near-infrared laser ablation of the iron target heated up to 600 °C enhances the particle generation efficiency by more than tenfold exceeding 6 μg/J. Temporal and thermal dependencies of the particle generation process indicate correlation of this enhancement with the oxidative processes that take place on the iron surface during the per spot interpulse delay. Nanoparticles, produced using the heat-assisted ablation technique, are examined using scanning electron and transmission electron microscopy confirming the presence of 1-100 nm nanoparticles with an exponential size distribution that contain multiple randomly oriented magnetite nanocrystallites. The described process enables the application of high power lasers and facilitates precise, uniform, and controllable direct deposition of ferric nanoparticle coatings at the industry-relevant rates.

The effect of thermal conductivity of the tool electrode in spark-assisted chemical engraving gravity-feed micro-drilling

International Nuclear Information System (INIS)

Mousa, M; Allagui, A; Ng, H D; Wüthrich, R

2009-01-01

Spark-assisted chemical engraving (SACE) is a non-traditional micro-machining technology based on electrochemical discharge phenomena. In SACE gravity-feed micro-drilling, various parameters including the thermal properties of the tool electrode play a significant role in the process. Based on a series of experiments using tool electrodes with different thermal properties, the effect in SACE gravity-feed micro-drilling is discussed. It is demonstrated that machining with higher thermal conductivity tool electrodes results in faster machining during the discharge regime and slower machining during the hydrodynamic regime of SACE gravity-feed micro-drilling

Hydrolysis of lactose with -D-galactosidase

Directory of Open Access Journals (Sweden)

Vesna Stehlik-Tomas

2001-06-01

Full Text Available The conditions of lactose hydrolysis with enzyme preparation of D-galactosidase were investigated. The aim of this work was to considered the use of whey in fermentative processes with yeast Saccharomyces cerevisiae. Enzymatic hydrolysis was conducted at different temperatures, with different lactose concentrations in medium and different concentrations of added enzyme. The results show that optimal temperature for hydrolysis was 40°C. The optimal amount of enzyme preparation was 2 gL-1 in lactose medium with 5-10 % lactose.

Determination of the content of alkyl ketene dimer in its latex by an ionic-liquid assisted headspace gas chromatography.

Science.gov (United States)

Yan, Ning; Wan, Xiao-Fang; Chai, Xin-Sheng; Chen, Run-Quan; Chen, Chun-Xia

2017-12-29

This paper reports on an ionic-liquid assisted headspace gas chromatographic (HS-GC) for the determination of the content of alkyl ketene dimer (AKD) in its latex samples, in which the GC system was equipped with a thermal conductivity detector (TCD). The method was based on the AKD hydrolysis conducted in 1-butyl-3-methylimidazolium chloride (ionic-liquid) added medium at 100°C for 10min in a closed headspace sample vial, and the measured CO 2 (the resulting product of the hydrolysis) by HS-GC. The results showed that the present method has a good measurement precision (RSD <2.3%) and accuracy (recoveries from 96 - 105%), and the limit of quantitation (LOQ) is 0.9%. The present method is very suitable to be used for the routine check of AKD content in its latex sample in mill applications. The study also showed that the content of AKD in the tested commercial latex samples were in the range of 3.5-12%. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental Assisted Fatigue Evaluation of Direct Vessel Injection Piping Considering Thermal Stratification

International Nuclear Information System (INIS)

Kim, Taesoon; Lee, Dohwan

2016-01-01

As the environmentally assisted fatigue (EAF) due to the primary water conditions is to be a critical issue, the fatigue evaluation for the components and pipes exposed to light water reactor coolant conditions has become increasingly important. Therefore, many studies to evaluate the fatigue life of the components and pipes in LWR coolant environments on fatigue life of materials have been conducted. Among many components and pipes of nuclear power plants, the direct vessel injection piping is known to one of the most vulnerable pipe systems because of thermal stratification occurred in that systems. Thermal stratification occurs because the density of water changes significantly with temperature. In this study, fatigue analysis for DVI piping using finite element analysis has been conducted and those results showed that the results met design conditions related with the environmental fatigue evaluation of safety class 1 pipes in nuclear power plants. Structural and fatigue integrity for the DVI piping system that thermal stratification occurred during the plant operation has conducted. First of all, thermal distribution of the piping system is calculated by computational fluid dynamic analysis to analyze the structural integrity of that piping system. And the fatigue life evaluation considering environmental effects was carried out. Our results showed that the DVI piping system had enough structural integrity and fatigue life during the design lifetime of 60 years

Anti-Inflammatory and Antioxidant Properties of Peptides Released from β-Lactoglobulin by High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis.

Science.gov (United States)

Bamdad, Fatemeh; Bark, Seonghee; Kwon, Chul Hee; Suh, Joo-Won; Sunwoo, Hoon

2017-06-07

β-lactoglobulin hydrolysates (BLGH) have shown antioxidant, antihypertensive, antimicrobial, and opioid activity. In the current study, an innovative combination of high hydrostatic pressure and enzymatic hydrolysis (HHP-EH) was used to increase the yield of short bioactive peptides, and evaluate the anti-inflammatory and antioxidant properties of the BLGH produced by the HHP-EH process. BLG was enzymatically hydrolyzed by different proteases at an enzyme-to-substrate ratio of 1:100 under HHP (100 MPa) and compared with hydrolysates obtained under atmospheric pressure (AP-EH at 0.1 MPa). The degree of hydrolysis (DH), molecular weight distribution, and the antioxidant and anti-inflammatory properties of hydrolysates in chemical and cellular models were evaluated. BLGH obtained under HHP-EH showed higher DH than the hydrolysates obtained under AP-EH. Free radical scavenging and the reducing capacity were also significantly stronger in HHP-BLGH compared to AP-BLGH. The BLGH produced by alcalase (Alc) (BLG-Alc) showed significantly higher antioxidant properties among the six enzymes examined in this study. The anti-inflammatory properties of BLG-HHP-Alc were observed in lipopolysaccharide-stimulated macrophage cells by a lower level of nitric oxide production and the suppression of the synthesis of pro-inflammatory cytokines. Peptide sequencing revealed that 38% of the amino acids in BLG-HHP-Alc are hydrophobic and aromatic residues, which contribute to its anti-inflammatory properties. Enzymatic hydrolysis of BLG under HHP produces a higher yield of short bioactive peptides with potential antioxidant and anti-inflammatory effects.

Exploration of process parameters for continuous hydrolysis of canola oil, camelina oil and algal oil

KAUST Repository

Wang, Weicheng

2012-07-01

Thermal hydrolysis of triglycerides to form free fatty acid (FFA) is a well-established industry practice. Recently, this process has been employed as a first step in the production of biofuels from lipids. To that end, batch and continuous hydrolysis of various feedstocks has been examined at the laboratory scale. Canola, the primary feedstock in this paper, camelina and algal oils were converted to high quality FFA. For the different reaction temperatures, the continuous hydrolysis system was found to provide better yields than the laboratory batch system. In addition, CFD simulation with ANSYS-CFX was used to model the performance and reactant/product separation in the continuous, counter-flow reactor. The effects of reaction temperature, water-to-oil ratio (ratio of water and oil volumetric inflow rate), and preheating of the reactants were examined experimentally. Optimization of these parameters has resulted in an improved, continuous process with high mass yields (89-93%, for reactor temperature of 260°C and water-to-oil ratio of 4:1) and energy efficiency (76%, for reactor temperature of 250°C and water-to-oil ratio of 2:1). Based on the product quality and energy efficiency considerations, the reactor temperature of 260°C and water-to-oil ratio of 4:1 have provided the optimal condition for the lab scale continuous hydrolysis reaction. © 2012 Elsevier B.V.

Exploration of process parameters for continuous hydrolysis of canola oil, camelina oil and algal oil

KAUST Repository

Wang, Weicheng; Turner, Timothy L.; Stikeleather, Larry F.; Roberts, William L.

2012-01-01

Thermal hydrolysis of triglycerides to form free fatty acid (FFA) is a well-established industry practice. Recently, this process has been employed as a first step in the production of biofuels from lipids. To that end, batch and continuous hydrolysis of various feedstocks has been examined at the laboratory scale. Canola, the primary feedstock in this paper, camelina and algal oils were converted to high quality FFA. For the different reaction temperatures, the continuous hydrolysis system was found to provide better yields than the laboratory batch system. In addition, CFD simulation with ANSYS-CFX was used to model the performance and reactant/product separation in the continuous, counter-flow reactor. The effects of reaction temperature, water-to-oil ratio (ratio of water and oil volumetric inflow rate), and preheating of the reactants were examined experimentally. Optimization of these parameters has resulted in an improved, continuous process with high mass yields (89-93%, for reactor temperature of 260°C and water-to-oil ratio of 4:1) and energy efficiency (76%, for reactor temperature of 250°C and water-to-oil ratio of 2:1). Based on the product quality and energy efficiency considerations, the reactor temperature of 260°C and water-to-oil ratio of 4:1 have provided the optimal condition for the lab scale continuous hydrolysis reaction. © 2012 Elsevier B.V.

Selective peptide bond hydrolysis of cysteine peptides in the presence of Ni(II) ions.

Science.gov (United States)

Protas, Anna Maria; Bonna, Arkadiusz; Kopera, Edyta; Bal, Wojciech

2011-01-01

Recently, we described a sequence-specific R1-(Ser/Thr) peptide bond hydrolysis reaction in peptides of a general sequence R1-(Ser/Thr)-Xaa-His-Zaa-R, which occurs in the presence of Ni(II) ions [A. Krężel, E. Kopera, A. M. Protas, A. Wysłouch-Cieszyńska, J. Poznański, W. Bal, J. Am. Chem. Soc. 132 (2010) 3355-3366]. In this study we explored the possibility of substituting the Ser/Thr and the His residues, necessary for the reaction to occur according to the Ni(II)-assisted acyl shift reaction mechanism, with Cys residues. We tested this concept by synthesizing three homologous peptides: R1-Ser-Arg-Cys-Trp-R2, R1-Cys-Arg-His-Trp-R2, and R1-Cys-Arg-Cys-Trp-R2, and the R1-Ser-Arg-His-Trp-R2 peptide as comparator (R1 and R2 were CH3CO-Gly-Ala and Lys-Phe-Leu-NH2, respectively). We studied their hydrolysis in the presence of Ni(II) ions, under anaerobic conditions and in the presence of TCEP as a thiol group antioxidant. We measured hydrolysis rates using HPLC and identified products of reaction using electrospray mass spectrometry. Potentiometry and UV-vis spectroscopy were used to assess Ni(II) complexation. We demonstrated that Ni(II) is not compatible with the Cys substitution of the Ser/Thr acyl acceptor residue, but the substitution of the Ni(II) binding His residue with a Cys yields a peptide susceptible to Ni(II)-related hydrolysis. The relatively high activity of the R1-Ser-Arg-Cys-Trp-R2 peptide at pH 7.0 suggests that this peptide and its Cys-containing analogs might be useful in practical applications of Ni(II)-dependent peptide bond hydrolysis. Copyright © 2010 Elsevier Inc. All rights reserved.

Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material

International Nuclear Information System (INIS)

Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

2016-01-01

Highlights: • The discharging process of a latent heat thermal energy storage system is studied. • The thermal energy storage system is assisted by finned heat pipes. • The influences of heat pipe spacing and fins geometrical features are studied. • Smaller heat pipe spacing enhances the solidification rate. • Better heat pipe and fin arrangements are determined. - Abstract: This paper presents the results of a numerical study conducted to investigate the discharging process of a latent heat thermal energy storage system assisted by finned heat pipes. A two-dimensional finite volume based numerical model along with enthalpy-porosity technique is employed to simulate the phase change of storage media during the discharging mode. The thermal energy storage system in this study consists of a square container, finned heat pipes, and potassium nitrate (KNO 3 ) as the phase change material. The charging process of the same thermal energy storage system was reported in an early paper by the authors. This paper reports the results of discharging process of the thermal energy storage system. The influences of heat pipe spacing, fin geometry and quantities as well as the effects of natural convection heat transfer on the thermal performance of the storage system were studied. The results indicate that the phase change material solidification process is hardly affected by the natural convection. Decreasing the heat pipe spacing results in faster discharging process and higher container base wall temperature. Increasing the fins length does not change the discharging time but yields higher base wall temperature. Using more fins also accelerates the discharging process and increases the container base wall temperature.

Kinetic modelling of enzymatic starch hydrolysis

NARCIS (Netherlands)

Bednarska, K.A.

2015-01-01

Kinetic modelling of enzymatic starch hydrolysis – a summary

K.A. Bednarska

The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

Conversion of rice straw to sugars by dilute-acid hydrolysis

International Nuclear Information System (INIS)

Karimi, Keikhosro; Kheradmandinia, Shauker; Taherzadeh, Mohammad J.

2006-01-01

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

Hydrolysis of alkaline pretreated banana peel

Science.gov (United States)

Fatmawati, A.; Gunawan, K. Y.; Hadiwijaya, F. A.

2017-11-01

Banana peel is one of food wastes that are rich in carbohydrate. This shows its potential as fermentation substrate including bio-ethanol. This paper presented banana peel alkaline pretreatment and enzymatic hydrolysis. The pretreatment was intended to prepare banana peel in order to increase hydrolysis performance. The alkaline pretreatment used 10, 20, and 30% w/v NaOH solution and was done at 60, 70 and 80°C for 1 hour. The hydrolysis reaction was conducted using two commercial cellulose enzymes. The reaction time was varied for 3, 5, and 7 days. The best condition for pretreatment process was one conducted using 30% NaOH solution and at 80°C. This condition resulted in cellulose content of 90.27% and acid insoluble lignin content of 2.88%. Seven-day hydrolysis time had exhibited the highest reducing sugar concentration, which was7.2869 g/L.

Enzymatic hydrolysis of plant extracts containing inulin

Energy Technology Data Exchange (ETDEWEB)

Guiraud, J.P.; Galzy, P.

1981-10-01

Inulin-rich extracts of chicory and Jerusalem artichoke are a good potential source of fructose. Total enzymatic hydrolysis of these extracts can be effected by yeast inulinases (EC 3.2.1.7). Chemical prehydrolysis is unfavourable. Enzymatic hydrolysis has advantages over chemical hydrolysis: it does not produce a dark-coloured fraction or secondary substances. It is possible to envisage the preparation of high fructose syrups using this process. (Refs. 42).

Thermal decomposition of synthetic antlerite prepared by microwave-assisted hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Koga, Nobuyoshi [Chemistry Laboratory, Graduate School of Education, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524 (Japan)], E-mail: nkoga@hiroshima-u.ac.jp; Mako, Akira; Kimizu, Takaaki; Tanaka, Yuu [Chemistry Laboratory, Graduate School of Education, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524 (Japan)

2008-01-30

Copper(II) hydroxide sulfate was synthesized by a microwave-assisted hydrothermal method from a mixed solution of CuSO{sub 4} and urea. Needle-like crystals of ca. 20-30 {mu}m in length precipitated by irradiating microwave for 1 min were characterized as Cu{sub 3}(OH){sub 4}SO{sub 4} corresponding to mineral antlerite. The reaction pathway and kinetics of the thermal decomposition of the synthetic antlerite Cu{sub 3}(OH){sub 4}SO{sub 4} were investigated by means of thermoanalytical techniques complemented by powder X-ray diffractometry and microscopic observations. The thermal decomposition of Cu{sub 3}(OH){sub 4}SO{sub 4} proceeded via two separated reaction steps of dehydroxylation and desulfation to produce CuO, where crystalline phases of Cu{sub 2}OSO{sub 4} and CuO appeared as the intermediate products. The kinetic characteristics of the respective steps were discussed in comparison with those of the synthetic brochantite Cu{sub 4}(OH){sub 6}SO{sub 4} reported previously.

Enzymatic hydrolysis of biomimetic bacterial cellulose-hemicellulose composites.

Science.gov (United States)

Penttilä, Paavo A; Imai, Tomoya; Hemming, Jarl; Willför, Stefan; Sugiyama, Junji

2018-06-15

The production of biofuels and other chemicals from lignocellulosic biomass is limited by the inefficiency of enzymatic hydrolysis. Here a biomimetic composite material consisting of bacterial cellulose and wood-based hemicelluloses was used to study the effects of hemicelluloses on the enzymatic hydrolysis with a commercial cellulase mixture. Bacterial cellulose synthesized in the presence of hemicelluloses, especially xylan, was found to be more susceptible to enzymatic hydrolysis than hemicellulose-free bacterial cellulose. The reason for the easier hydrolysis could be related to the nanoscale structure of the substrate, particularly the packing of cellulose microfibrils into ribbons or bundles. In addition, small-angle X-ray scattering was used to show that the average nanoscale morphology of bacterial cellulose remained unchanged during the enzymatic hydrolysis. The reported easier enzymatic hydrolysis of bacterial cellulose produced in the presence of wood-based xylan offers new insights to overcome biomass recalcitrance through genetic engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of a procedure for forming assisted thermal joining of tubes

Science.gov (United States)

Chen, Hui; Löbbe, Christian; Staupendahl, Daniel; Tekkaya, A. Erman

2018-05-01

With the demand of lightweight design in the automotive industry, not only the wall-thicknesses of tubular components of the chassis or spaceframe are continuously decreased. Also the thicknesses of exhaust system parts are reduced to save material and mass. However, thinner tubular parts bring about additional challenges in joining. Welding or brazing methods, which are utilized in joining tubes with specific requirements concerning leak tightness, are sensitive to the gap between the joining partners. Furthermore, a large joining area is required to ensure the durability of the joint. The introduction of a forming step in the assembled state prior to thermal joining can define and control the gap for subsequent brazing or welding. The mechanical pre-joint resulting from the previously described calibration step also results in easier handling of the tubes prior to thermal joining. In the presented investigation, a spinning process is utilized to produce force-fit joints of varying lengths and diameter reduction and form-fit joints with varying geometrical attributes. The spinning process facilitates a high formability and geometrical flexibility, while at the achievable precision is high and the process forces are low. The strength of the joints is used to evaluate the joint quality. Finally, a comparison between joints produced by forming with subsequent brazing and original tube is conducted, which presents the high performance of the developed procedure for forming assisted thermal joining.

Experimental Investigation of A Heat Pipe-Assisted Latent Heat Thermal Energy Storage System

Science.gov (United States)

Tiari, Saeed; Mahdavi, Mahboobe; Qiu, Songgang

2016-11-01

In the present work, different operation modes of a latent heat thermal energy storage system assisted by a heat pipe network were studied experimentally. Rubitherm RT55 enclosed by a vertical cylindrical container was used as the Phase Change Material (PCM). The embedded heat pipe network consisting of a primary heat pipe and an array of four secondary heat pipes were employed to transfer heat to the PCM. The primary heat pipe transports heat from the heat source to the heat sink. The secondary heat pipes transfer the extra heat from the heat source to PCM during charging process or retrieve thermal energy from PCM during discharging process. The effects of heat transfer fluid (HTF) flow rate and temperature on the thermal performance of the system were investigated for both charging and discharging processes. It was found that the HTF flow rate has a significant effect on the total charging time of the system. Increasing the HTF flow rate results in a remarkable increase in the system input thermal power. The results also showed that the discharging process is hardly affected by the HTF flow rate but HTF temperature plays an important role in both charging and discharging processes. The authors would like to acknowledge the financial supports by Temple University for the project.

Effect of metal ions on the enzymatic hydrolysis of hemp seed oil by lipase Candida sp. 99-125.

Science.gov (United States)

Lu, Jike; Wang, Pei; Ke, Zhaodi; Liu, Xin; Kang, Qiaozhen; Hao, Limin

2018-07-15

In order to study the effect of metal ions on the enzymatic hydrolysis of hemp seed oil by Candida sp. 99-125, the spectroscopy, stability and hydrolytic activity of the biocatalyst were investigated in presence of Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Cu 2+ , Sn 2+ , Pb 2+ , Zn 2+ and Ba 2+ metal ions, respectively. The UV spectroscopy showed that all the metal ions enhanced the absorbance but the decrease of fluorescence intensity was observed. All the metal ions could improve the lipase thermal stability except Cu 2+ and Ba 2+ . Hydrolysis of hemp seed oil proved that Ca 2+ , Fe 3+ , Pb 2+ and Ba 2+ could significantly improve the hydrolytic rate, and metal ions could influence lipase selectivity. The study revealed that metal ions could improve lipase stability, hydrolysis activity in the hydrolytic process of hemp seed oil by Candida sp. 99-125. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of a thermally assisted mechanical dewatering process to biomass

Energy Technology Data Exchange (ETDEWEB)

Mahmoud, A.; Arlabosse, P. [Universite de Toulouse, Mines Albi, CNRS, Campus Jarlard, F-81013 Albi cedex 09 (France); Ecole des Mines Albi, Centre RAPSODEE, Campus Jarlard, F-81013 Albi (France); Fernandez, A. [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31400 Toulouse (France); INRA, UMR792 Ingenierie des Systemes Biologiques et des Procedes, CNRS, UMR5504, F-31400 Toulouse (France)

2011-01-15

Thermally assisted mechanical dewatering (TAMD) is a new process for energy-efficient liquid/solids separation which enhances conventional-device efficiency. The main idea of this process is to supply a flow of heat in mechanical dewatering processes to favour the reduction of the liquid content. This is not a new idea but the proposed combination, especially the chosen operating conditions (T < 100 C and P < 3000 kPa) constitutes an original approach and a significant energy saving since the liquid is kept in liquid state. Response surface methodology was used to evaluate the effects of the processing parameters of TAMD on the final dry solids content, which is a fundamental dewatering parameter and an excellent indicator of the extent of TAMD. In this study, a two-factor central composite design was used to establish the optimum conditions for the TAMD of alfalfa biomass. Experiments were carried out on a laboratory compression cell. Experiments showed that the dewatering enhancement results only from thermal effects. With a moderate heat supply (T{sub piston} = 80 C), the dry solid content of the press cake can reach 66%, compared to 36% at ambient temperature. A significant regression model, describing changes on final dry solids content with respect to independent variables, was established with determination coefficient, R{sup 2}, greater than 88%. With an energy consumption of less than 150 kWh/m{sup 3}, the use of the TAMD process before a thermal drying process leads to an energy saving of at least 30% on the overall separation chain. (author)

Kinetics of enzymatic hydrolysis of methyl ricinoleate

OpenAIRE

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

2015-01-01

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

Bioethanol production: an integrated process of low substrate loading hydrolysis-high sugars liquid fermentation and solid state fermentation of enzymatic hydrolysis residue.

Science.gov (United States)

Chu, Qiulu; Li, Xin; Ma, Bin; Xu, Yong; Ouyang, Jia; Zhu, Junjun; Yu, Shiyuan; Yong, Qiang

2012-11-01

An integrated process of enzymatic hydrolysis and fermentation was investigated for high ethanol production. The combination of enzymatic hydrolysis at low substrate loading, liquid fermentation of high sugars concentration and solid state fermentation of enzymatic hydrolysis residue was beneficial for conversion of steam explosion pretreated corn stover to ethanol. The results suggested that low substrate loading hydrolysis caused a high enzymatic hydrolysis yield; the liquid fermentation of about 200g/L glucose by Saccharomyces cerevisiae provided a high ethanol concentration which could significantly decrease cost of the subsequent ethanol distillation. A solid state fermentation of enzymatic hydrolysis residue was combined, which was available to enhance ethanol production and cellulose-to-ethanol conversion. The results of solid state fermentation demonstrated that the solid state fermentation process accompanied by simultaneous saccharification and fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Gonioscopy-assisted Transluminal Trabeculotomy (GATT): Thermal Suture Modification With a Dye-stained Rounded Tip.

Science.gov (United States)

Grover, Davinder S; Fellman, Ronald L

2016-06-01

To describe a novel technique for thermally marking the tip of a suture, in preparation for a gonioscopy-assisted transluminal trabeculotomy. One patient was used as an example for this technique. Technique report. The authors introduce a modification of a novel surgical procedure (GATT) in which a suture is marked and thermally blunted allowing a proper visualization while performing an ab interno, minimally invasive, circumferential 360-degree suture trabeculotomy. The authors have previously reported on the GATT surgery with the use of an illuminated microcatheter, which allowed for visualization of the tip of the catheter as it circumnavigated Schlemm canal. This modification allows for similar visualization of the tip of the suture, however, is much more cost-effective while still maintaining similar safety.

Computer-assisted training in the thermal production department

International Nuclear Information System (INIS)

Felgines, R.

1985-01-01

For many years now, in the United States and Canada, computer-assisted training (CAT) experiments have been carried out in various fields: general or professional education, student testing in universities. This method seems very promising and particularly for continuing education and for keeping industrial process operating and maintenance personnel abreast of their specialities. Thanks to the progress in data processing and remote processing with central computers, this technique is being developed in France for professional training applications. Faced with many training problems, the Thermal Production Department of EDF (Electricite de France) first conducted in 1979 a test involving a limited subset of the nuclear power station operating personnel; this course amounted to some ten hours with very limited content. It seemed promising enough, so that in 1981, a real test was launched at 4 PWR plants: DAMPIERRE, FESSENHEIM, GRAVELINES, TRICASTIN. This test which involves about 700 employees has been fruitful and we decided to generalise this system to all the French nuclear power plants (40 units of 900 and 1300 MW). (author)

Defense waste processing facility precipitate hydrolysis process

International Nuclear Information System (INIS)

Doherty, J.P.; Eibling, R.E.; Marek, J.C.

1986-03-01

Sodium tetraphenylborate and sodium titanate are used to assist in the concentration of soluble radionuclide in the Savannah River Plant's high-level waste. In the Defense Waste Processing Facility, concentrated tetraphenylborate/sodium titanate slurry containing cesium-137, strontium-90 and traces of plutonium from the waste tank farm is hydrolyzed in the Salt Processing Cell forming organic and aqueous phases. The two phases are then separated and the organic phase is decontaminated for incineration outside the DWPF building. The aqueous phase, containing the radionuclides and less than 10% of the original organic, is blended with the insoluble radionuclides in the high-level waste sludge and is fed to the glass melter for vitrification into borosilicate glass. During the Savannah River Laboratory's development of this process, copper (II) was found to act as a catalyst during the hydrolysis reactions, which improved the organic removal and simplified the design of the reactor

Growth of wrinkle-free graphene on texture-controlled platinum films and thermal-assisted transfer of large-scale patterned graphene.

Science.gov (United States)

Choi, Jae-Kyung; Kwak, Jinsung; Park, Soon-Dong; Yun, Hyung Duk; Kim, Se-Yang; Jung, Minbok; Kim, Sung Youb; Park, Kibog; Kang, Seoktae; Kim, Sung-Dae; Park, Dong-Yeon; Lee, Dong-Su; Hong, Suk-Kyoung; Shin, Hyung-Joon; Kwon, Soon-Yong

2015-01-27

Growth of large-scale patterned, wrinkle-free graphene and the gentle transfer technique without further damage are most important requirements for the practical use of graphene. Here we report the growth of wrinkle-free, strictly uniform monolayer graphene films by chemical vapor deposition on a platinum (Pt) substrate with texture-controlled giant grains and the thermal-assisted transfer of large-scale patterned graphene onto arbitrary substrates. The designed Pt surfaces with limited numbers of grain boundaries and improved surface perfectness as well as small thermal expansion coefficient difference to graphene provide a venue for uniform growth of monolayer graphene with wrinkle-free characteristic. The thermal-assisted transfer technique allows the complete transfer of large-scale patterned graphene films onto arbitrary substrates without any ripples, tears, or folds. The transferred graphene shows high crystalline quality with an average carrier mobility of ∼ 5500 cm(2) V(-1) s(-1) at room temperature. Furthermore, this transfer technique shows a high tolerance to variations in types and morphologies of underlying substrates.

Unravelling the distinct crystallinity and thermal properties of suberin compounds from Quercus suber and Betula pendula outer barks.

Science.gov (United States)

Sousa, Andreia F; Gandini, Alessandro; Caetano, Ana; Maria, Teresa M R; Freire, Carmen S R; Neto, Carlos Pascoal; Silvestre, Armando J D

2016-12-01

The main purpose of this study was to investigate the potential of suberin (a naturally occurring aromatic-aliphatic polyester ubiquitous to the vegetable realm) as a renewable source of chemicals and, in particular, to assess their physical properties. A comparison between cork and birch suberin fragments obtained by conventional depolymerisation processes (hydrolysis or methanolysis) is provided, focusing essentially on their thermal and crystallinity properties. It was found that suberin fragments obtained by the hydrolysis depolymerisation of birch had a high degree of crystallinity, as indicated by their thermal analysis and corroborated by the corresponding XRD diffractions, as opposed to hydrolysis-depolymerised cork suberin counterparts, which were essentially amorphous. Copyright © 2016 Elsevier B.V. All rights reserved.

X-ray diffraction, IR spectroscopy and thermal characterization of partially hydrolyzed guar gum.

Science.gov (United States)

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2012-05-01

Guar gum was hydrolyzed using cellulase from Aspergillus niger at 5.6 pH and 50°C temperature. Hydrolyzed guar gum sample was characterized using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, dilute solution viscometry and rotational viscometry. Viscometry analysis of native guar gum showed a molecular weight of 889742.06, whereas, after enzymatic hydrolysis, the resultant product had a molecular weight of 7936.5. IR spectral analysis suggests that after enzymatic hydrolysis of guar gum there was no major transformation of functional group. Thermal analysis revealed no major change in thermal behavior of hydrolyzed guar gum. It was shown that partial hydrolysis of guar gum could be achieved by inexpensive and food grade cellulase (Aspergillus niger) having commercial importance and utilization as a functional soluble dietary fiber for food industry. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrolysis reactor for hydrogen production

Science.gov (United States)

Davis, Thomas A.; Matthews, Michael A.

2012-12-04

In accordance with certain embodiments of the present disclosure, a method for hydrolysis of a chemical hydride is provided. The method includes adding a chemical hydride to a reaction chamber and exposing the chemical hydride in the reaction chamber to a temperature of at least about 100.degree. C. in the presence of water and in the absence of an acid or a heterogeneous catalyst, wherein the chemical hydride undergoes hydrolysis to form hydrogen gas and a byproduct material.

Optimizing the Isolation of Microfibrillated Bamboo in High Pressure Enzymatic Hydrolysis

Directory of Open Access Journals (Sweden)

N. A. Sri Aprilia

2015-07-01

Full Text Available Bleached bamboo fiber was treated with a high pressure enzymatic hydrolysis (HPEH process in order to produce microfibrillated bamboo fiber (MBF. Mixture design of experiments was utilized to determine the optimal constituents of fiber, enzymes, and water for the HPEH process on the isolation yield of the MBF. Results showed the optimal combination for the maximal yield isolation of the MBF was 1 g fiber, 1 g enzyme, and 1 L water at 90 MPa and 70 °C. The influence of the reaction time of the HPEH process (6 to 48 h was also evaluated in this study. Morphological and thermal property analyses of untreated and treated bamboo fibers revealed that the HPEH process was effective for removing non-cellulosic components from the fibers. Thus, the HPEH process is an effective method for the isolation of the MBF, with the benefits of elevated crystallinity and thermal stability.

A novel solar-assisted heat pump driven by photovoltaic/thermal collectors: Dynamic simulation and thermoeconomic optimization

International Nuclear Information System (INIS)

Calise, Francesco; Dentice d'Accadia, Massimo; Figaj, Rafal Damian; Vanoli, Laura

2016-01-01

This paper presents a dynamic simulation model and a thermo-economic analysis of a novel polygeneration system based on a solar-assisted heat pump and an adsorption chiller, both driven by PVT (photovoltaic/thermal) collectors. The aim of this work is to design and dynamically simulate a novel ultra-high efficient solar heating and cooling system. The overall plant layout is designed to supply electricity, space heating and cooling and domestic hot water for a small residential building. The system combines solar cooling, solar-assisted heat pump and photovoltaic/thermal collector technologies in a novel solar polygeneration system. In fact, the polygeneration system is based on a PVT solar field, coupled with a water-to-water electric heat pump or to an adsorption chiller. PVT collectors simultaneously produce electricity and thermal energy. During the winter, hot water produced by PVT collectors primarily supplies the evaporator of the heat pump, whereas in summer, solar energy supplies an adsorption chiller providing the required space cooling. All year long, solar thermal energy in excess is converted into DHW (domestic hot water). The system model was developed in TRNSYS environment. 1-year dynamic simulations are performed for different case studies in various weather conditions. The results are analysed on different time bases presenting energetic, environmental and economic performance data. Finally, a sensitivity analysis and a thermoeconomic optimization were performed, in order to determine the set of system design/control parameters that minimize the simple pay-back period. The results showed a total energy efficiency of the PVT of 49%, a heat pump yearly coefficient of performance for heating mode above 4 and a coefficient of performance of the adsorption chiller of 0.55. Finally, it is also concluded that system performance is highly sensitive to the PVT field area. The system is profitable when a capital investment subsidy of 50% is considered

Fundamental research on the gravity assisted heat pipe thermal storage unit (GAHP-TSU) with porous phase change materials (PCMs) for medium temperature applications

International Nuclear Information System (INIS)

Hu, Bo-wen; Wang, Qian; Liu, Zhen-Hua

2015-01-01

Highlights: • A novel gravity-assisted heat pipe thermal storage unit (GAHP-TSU) is presented and tested. • Composite granular solid–liquid PCM is piled up as the porous medium layer in GAHP-TSU. • GAHP-TSU avoids the major obstacle of low thermal conductivity of the PCM. • GAHP-TSU enables the thermal storage unit with outstanding heat transfer performance. - Abstract: In this study, a novel gravity-assisted heat pipe type thermal storage unit (GAHP-TSU) has been presented for the potential application in solar air conditioning and refrigeration systems, in which composite granular solid–liquid PCMs compounded by RT100 and high-density polyethylene with phase change temperature of 100 °C are piled up as a porous PCMs medium layer. Water is used as heat transfer fluid in the GAHP-TSU. The heat transfer mechanism of heat storage/release in the GAHP-TSU is similar to that of the gravity-assisted heat pipe, which is superior to traditional direct-contact or indirect-contact thermal storage units. The properties of start-up, heat transfer characteristics on the stages of heat absorption and release of the GAHP-TSU are studied in detailed, including necessary calculations based on heat transfer theory. The results show that the whole system is almost isothermal at the temperature over 70 °C and the heat transfer properties are excellent both for heat absorption and release stages. The GAHP-TSU device with low thermal conductivity of the PCMs is promising in potential industry applications

Hydrolysis of corn oil using subcritical water

Directory of Open Access Journals (Sweden)

Pinto Jair Sebastião S.

2006-01-01

Full Text Available This work presents the results of a study on the use of subcritical water as both solvent and reactant for the hydrolysis of corn oil without the use of acids or alkalis at temperatures of 150-280 degreesC. Corn oil hydrolysis leads to the formation of its respective fatty acids with the same efficiency of conventional methods. Fatty acids form an important group of products, which are used in a range of applications. The confirmation and identification of the hydrolysis products was done by HT-HRGC-FID and HRGC/MS.

Hydrothermal treatment followed by enzymatic hydrolysis and hydrothermal carbonization as means to valorise agro- and forest-based biomass residues.

Science.gov (United States)

Wikberg, Hanne; Grönqvist, Stina; Niemi, Piritta; Mikkelson, Atte; Siika-Aho, Matti; Kanerva, Heimo; Käsper, Andres; Tamminen, Tarja

2017-07-01

The suitability of several abundant but underutilized agro and forest based biomass residues for hydrothermal treatment followed by enzymatic hydrolysis as well as for hydrothermal carbonization was studied. The selected approaches represent simple biotechnical and thermochemical treatment routes suitable for wet biomass. Based on the results, the hydrothermal pre-treatment followed by enzymatic hydrolysis seemed to be most suitable for processing of carbohydrate rich corn leaves, corn stover, wheat straw and willow. High content of thermally stable components (i.e. lignin) and low content of ash in the biomass were advantageous for hydrothermal carbonization of grape pomace, coffee cake, Scots pine bark and willow. Copyright © 2017 Elsevier Ltd. All rights reserved.

Immobilization of α-amylase and amyloglucosidase onto ion-exchange resin beads and hydrolysis of natural starch at high concentration.

Science.gov (United States)

Gupta, Kapish; Jana, Asim Kumar; Kumar, Sandeep; Maiti, Mithu

2013-11-01

α-Amylase was immobilized on Dowex MAC-3 with 88 % yield and amyloglucosidase on Amberlite IRA-400 ion-exchange resin beads with 54 % yield by adsorption process. Immobilized enzymes were characterized to measure the kinetic parameters and optimal operational parameters. Optimum substrate concentration and temperature were higher for immobilized enzymes. The thermal stability of the enzymes enhanced after the immobilization. Immobilized enzymes were used in the hydrolysis of the natural starch at high concentration (35 % w/v). The time required for liquefaction of starch to 10 dextrose equivalent (DE) and saccharification of liquefied starch to 96 DE increased. Immobilized enzymes showed the potential for use in starch hydrolysis as done in industry.

Kinetics of catalyzed hydrolysis of 4-methylumbelliferyl caprylate (MUCAP) salmonella reagent

Science.gov (United States)

Al-Kady, Ahmed S.; Ahmed, El-Sadat I.; Gaber, M.; Hussein, Mohamed M.; Ebeid, El-Zeiny M.

2011-09-01

The kinetics of chemical hydrolysis including neutral, acid- and base-catalyzed hydrolysis of 4-methylumbelliferyl caprylate (MUCAP) salmonella reagent were studied at different temperatures. The rate constants and activation parameters were determined by following the build-up of fluorescence peak of the hydrolysis product 4-methylumbelliferone (4-MU). The time scale of esterase enzyme hydrolysis caused by salmonella was compared with chemical hydrolysis as a background process.

Short-time ultrasonication treatment in enzymatic hydrolysis of biomass

Science.gov (United States)

Zengqian Shi; Zhiyong Cai; Siqun Wang; Qixin Zhong; Joseph J. Bozell

2013-01-01

To improve the conversion of enzymatic hydrolysis of biomass in an energy-efficient manner, two shorttime ultrasonication strategies were applied on six types of biomass with different structures and components. The strategies include pre-sonication before the hydrolysis and intermittent sonication during the ongoing hydrolysis. The microstructures of each type of...

Highly thermal-stable and functional cellulose nanocrystals and nanofibrils produced using fully recyclable organic acids

Science.gov (United States)

Liheng Chen; Junyong Zhu; Carlos Baez; Peter Kitin; Thomas Elder

2016-01-01

Here we report the production of highly thermal stable and functional cellulose nanocrystals (CNC) and nanofibrils (CNF) by hydrolysis using concentrated organic acids. Due to their low water solubility, these solid organic acids can be easily recovered after hydrolysis reactions through crystallization at a lower or ambient temperature. When dicarboxylic acids were...

[Prediction of common buffer catalysis in hydrolysis of fenchlorazole-ethyl].

Science.gov (United States)

Lin, Jing; Chen, Jing-wen; Zhang, Si-yu; Cai, Xi-yun; Qiao, Xian-liang

2008-09-01

The purpose of this study was to elucidate the effects of temperatures, pH levels and buffer catalysis on the hydrolysis of FCE. The hydrolysis of FCE follows first-order kinetics at different pH levels and temperatures. FCE hydrolysis rates are greatly increased at elevated pH levels and temperatures. The maximum contribution of buffer catalysis to the hydrolysis of FCE was assessed based on application of the Bronsted equations for general acid-base catalysis. The results suggest that the buffer solutions play an obvious catalysis role in hydrolysis of FCE and the hydrolysis rates of FCE are quickened by the buffer solutions. Besides, the buffer catalysis capacity of different buffer solutions is diverse, and the buffer catalysis capacity at different pH levels with the same buffer solutions is different, too. The phosphate buffer at pH = 7 shows the maximal buffer catalysis capacity. The hydrolysis rate constants of FCE as a function of temperature and pH, which were remedied by the buffer catalysis factor, were mathematically combined to predict the hydrolytic dissipation of FCE. The equation suggests that the hydrolysis half-lives of FCE ranged from 7 d to 790 d. Hydrolysis metabolites of FCE were identified by liquid chromatography-mass spectrometry. In basic conditions (pH 8-10), fenchlorazole was formed via breakdown of the ester bond of the safener.

Synthesis and spectral characterization of 2,2-diphenylethyl glucosinolate and HPLC-based reaction progress curve data for the enzymatic hydrolysis of glucosinolates by Sinapis alba myrosinase

Directory of Open Access Journals (Sweden)

Chase A. Klingaman

2017-02-01

Full Text Available The data presented in this article are related to the research article, “HPLC-based enzyme kinetics assay for glucosinolate hydrolysis facilitate analysis of systems with both multiple reaction products and thermal enzyme denaturation” (C.K. Klingaman, M.J. Wagner, J.R. Brown, J.B. Klecker, E.H. Pauley, C.J. Noldner, J.R. Mays, [1]. This data article describes (1 the synthesis and spectral characterization data of a non-natural glucosinolate analogue, 2,2-diphenylethyl glucosinolate, (2 HPLC standardization data for glucosinolate, isothiocyanate, nitrile, and amine analytes, (3 reaction progress curve data for enzymatic hydrolysis reactions with variable substrate concentration, enzyme concentration, buffer pH, and temperature, and (4 normalized initial velocities of hydrolysis/formation for analytes. These data provide a comprehensive description of the enzyme-catalyzed hydrolysis of 2,2-diphenylethyl glucosinolate (5 and glucotropaeolin (6 under widely varied conditions.

Hydrolysis of lactose: a literature review

Energy Technology Data Exchange (ETDEWEB)

Gekas, V; Lopez-Leiva, M

1985-02-01

Lactose is the sugar found in milk and whey. Its hydrolysis to glucose and galactose in milk would solve the problem of milk-intolerant people and in whey it would avoid environmental pollution and offer an interesting possibility of by-product utilization. The prepared sweet syrup has many potential applications in the food industry. Hydrolysis of lactose can be carried out by heating at low pH (acid hydrolysis) or by enzymatic catalysis with the enzyme (lactase or ..beta..-D-galactosidase) either free in solution or immobilized by one of the several enzyme immobilization methods which are abundant in the literature. Selection of the proper method depends on many factors: the nature of substrate, use of the final product, need for sanitary conditions, and, of course, capital and processing costs. 157 references.

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

Science.gov (United States)

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Hydrolysis of molten CaCl2-CaF2 with additions of CaO

Directory of Open Access Journals (Sweden)

Espen Olsen

2017-10-01

Full Text Available Calcium halide based molten salts have recently attracted interest for a number of applications such as direct reduction of oxides for metal production and as liquefying agent in cyclic sorption processes for CO2 by CaO from dilute flue gases (Ca-looping. A fundamental aspect of these melts is the possible hydrolysis reaction upon exposure to gaseous H2O forming corrosive and poisonous hydrogen halides. In this work experiments have been performed investigating the formation of HCl and HF from a molten salt consisting of a 13.8 wt% CaF2 in CaCl2 eutectic exposed to a flowing gas consisting of 10 vol% H2O in N2. Hydrolysis has been investigated as function of content of CaO and temperature. HCl and HF are shown to be formed at elevated temperatures; HCl forms to a substantially larger extent than HF. Addition of CaO has a marked, limiting effect on the hydrolysis. Thermodynamic modeling of the reaction indicates activity coefficients for CaO above unity in the system. For cyclic CO2-capture based on thermal swing, it is advisable to keep the temperature in the carbonation (absorption reactor well below 850 ℃ while maintaining a high CaO content if molten CaCl2 is employed. Similar conclusions can be drawn with regards to CaF2.

Thermal Stability of Rhodopsin and Progression of Retinitis Pigmentosa

Science.gov (United States)

Liu, Monica Yun; Liu, Jian; Mehrotra, Devi; Liu, Yuting; Guo, Ying; Baldera-Aguayo, Pedro A.; Mooney, Victoria L.; Nour, Adel M.; Yan, Elsa C. Y.

2013-01-01

Over 100 point mutations in the rhodopsin gene have been associated with retinitis pigmentosa (RP), a family of inherited visual disorders. Among these, we focused on characterizing the S186W mutation. We compared the thermal properties of the S186W mutant with another RP-causing mutant, D190N, and with WT rhodopsin. To assess thermal stability, we measured the rate of two thermal reactions contributing to the thermal decay of rhodopsin as follows: thermal isomerization of 11-cis-retinal and hydrolysis of the protonated Schiff base linkage between the 11-cis-retinal chromophore and opsin protein. We used UV-visible spectroscopy and HPLC to examine the kinetics of these reactions at 37 and 55 °C for WT and mutant rhodopsin purified from HEK293 cells. Compared with WT rhodopsin and the D190N mutant, the S186W mutation dramatically increases the rates of both thermal isomerization and dark state hydrolysis of the Schiff base by 1–2 orders of magnitude. The results suggest that the S186W mutant thermally destabilizes rhodopsin by disrupting a hydrogen bond network at the receptor's active site. The decrease in the thermal stability of dark state rhodopsin is likely to be associated with higher levels of dark noise that undermine the sensitivity of rhodopsin, potentially accounting for night blindness in the early stages of RP. Further studies of the thermal stability of additional pathogenic rhodopsin mutations in conjunction with clinical studies are expected to provide insight into the molecular mechanism of RP and test the correlation between rhodopsin's thermal stability and RP progression in patients. PMID:23625926

Chemical Changes in Carbohydrates Produced by Thermal Processing.

Science.gov (United States)

Hoseney, R. Carl

1984-01-01

Discusses chemical changes that occur in the carbohydrates found in food products when these products are subjected to thermal processing. Topics considered include browning reactions, starch found in food systems, hydrolysis of carbohydrates, extrusion cooking, processing of cookies and candies, and alterations in gums. (JN)

Effect of salting on back fat hydrolysis and oxidation

Science.gov (United States)

Tunieva, E. К; Nasonova, V. V.; Stanovova, I. A.; Spiridonov, К I.; Kurzova, A. A.

2017-09-01

Technological factors significantly affect the rate of hydrolytic and oxidative changes in fat. The aim of the research was to study the effect of sodium chloride on hydrolysis and oxidation of fat raw material, including the impact of thermal treatment. Back fat was minced, sodium chloride was added (in amounts of 0.0, 2.0, 3.5 or 5.0%), then it was thermally treated or not. Determination of the acid value (AV) was carried out by titration with aqueous potassium hydroxide of free fatty acids in the ether-alcohol solution of back fat; the peroxide value (PV) was based on oxidation of iodhydric acid with peroxides contained in fat followed by titration of released iodine with sodium thiosulphate. The thiobarbituric acid value (TBAV) was determined by the development of stained substances due to interaction of fat oxidation products with 2-thiobarbituric acid and measurement of color intensity using a spectrophotometer. Adding 5.0% sodium chloride to back fat led to a 30.1% decrease in AV. Addition of 2.0% sodium chloride inhibited the development of the oxidation products and led to a 17% decrease in the PV and to a 25% decrease in TBAV (p0.05). The results obtained showed an ambiguous effect of sodium chloride on the processes of fat oxidation, depending on dosage and the use of thermal treatment, justifying the necessity to develop approaches that allow reduction of the sodium chloride content in meat products that are not subjected to thermal treatment.

Water concentration controlled hydrolysis and crystallization in n-octanol to TiO{sub 2} nanocrystals with size below 10 nm

Energy Technology Data Exchange (ETDEWEB)

Wang Meilan [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); He Tao, E-mail: htzy79@yahoo.com.cn [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Pan Yanfei; Liao Weiping [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Zhang Shangzhou; Du Wei [School of Environment and Materials Engineering, Yantai University, Yantai 264005 (China)

2011-11-01

Highlights: {yields} Controlled hydrolysis of alkoxide was realized by adjusting water concentration. {yields} Carrying out hydrolysis under different water concentration gave hydrolyzed intermediate with different composition. {yields} A precise size control below 10 nm for anatase TiO{sub 2} nanocrystals was realized. - Abstract: Hydrolysis of tetrabutyl titanate (TBT) and crystallization from hydrolyzed intermediates were carried out in a simple ternary system including n-octanol, TBT and water. Anatase TiO{sub 2} nanocrystals (NCS) were prepared with precise size control below 10 nm. The hydrolysis rate at different water concentration (C{sub water}) was evaluated by measuring the induction time before turbidity changing of the synthetic solution. Fourier transform infrared spectrum (FT-IR) and thermogravimetric/differential thermal analysis (TG/DTA) techniques were applied to make clear the composition of hydrolyzed intermediates obtained at different C{sub water}. Powder X-ray diffraction (XRD) technique was used to track the crystallization process of TiO{sub 2} NCS. Transmission electron microscopy (TEM), XRD, FT-IR and TG/DTA techniques were used to characterize the particular properties of NCS. The C{sub water} controlled mechanism responsible for the slow hydrolysis and crystallization were discussed. Since no other organic capping ligands or rapid injecting techniques were used to limit NCS' growth and the solvent n-octanol can be easily separated and reused, this simple synthetic process is of green chemistry and has application potential in large-scale preparation of inorganic NCS.

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

Science.gov (United States)

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 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study of the hydrolysis reaction of the copper-chloride hybrid thermochemical cycle using optical spectrometries

International Nuclear Information System (INIS)

Doizi, D.; Borgard, J.M.; Dauvois, V.; Roujou, J.L.; Zanella, Y.; Croize, L.; Cartes, Ph.; Hartmann, J.M.

2010-01-01

The copper-chloride hybrid thermochemical cycle is one of the best potential low temperature thermochemical cycles for the massive production of hydrogen. It could be used with nuclear reactors such as the sodium fast reactor or the supercritical water reactor. Nevertheless, this thermochemical cycle is composed of an electrochemical reaction and two thermal reactions. Its efficiency has to be compared with other hydrogen production processes like alkaline electrolysis for example. The purpose of this article is to study the viability of the copper chloride thermochemical cycle by studying the hydrolysis reaction of CuCl 2 which is not favoured thermodynamically. To better understand the occurrence of possible side reactions, together with a good control of the kinetics of the hydrolysis reaction, the use of optical absorption spectrometries, UV visible spectrometry to detect molecular chlorine which may be formed in side reactions, FTIR spectrometry to follow the concentrations of H 2 O and HCl is proposed. (authors)

Influence of relativistic effects on hydrolysis of Ra2+

International Nuclear Information System (INIS)

Zielinska, B.; Bilewicz, A.

2005-01-01

Using 224 Ra radiotracer the first hydrolysis constant (pK 1h ) of Ra 2+ cations has been determined. The pK 1h value of Ra 2+ was compared with the pK 1h values of other Group 2 cations. It has been shown that the electrostatic hydrolysis model based on assumption that pK 1h is a linear function of reciprocal ionic radii (1/r i ) does not describe well the hydrolysis of Group 2 metal cations. The reason of higher Ra 2+ hydrolysis as expected is the influence of relativistic effects on bonding 7s and 7p 1/2 orbitals. (author)

Hydrolysis-extraction of apple proto pectins in dynamic mode

International Nuclear Information System (INIS)

Bobodzhonova, G.N.; Gorshkova, R.M.; Makhkamov, Kh.K.

2013-01-01

The article describes a hydrolysis process of apple husks by using dynamics regime of hydrolysis. It's shown that application of dynamics method positively influences on the pectin yields and its main parameters. It was defined that by dynamics regime of hydrolysis-extraction of apple husks it is possible to obtain qualitative products with high yield at a mild ph value of medium of hydrolysing agent.

HYDROLYSIS OF CHEESEWHEY PROTEINSWITH TRYPSIN, CHYMOTRYPSINAND CARBOXYPEPTIDASEA

Directory of Open Access Journals (Sweden)

M. F. CUSTÓDIO

2009-01-01

Full Text Available

This work presents a method for adding value to cheese whey residues by whey proteins hydrolysis, using trypsin, chymotrypsin and carboxypeptidase A as catalysts. Sweet cheese whey was dialyzed and filtered in kaolin. Lactose and protein contents were analyzed after each step. The activities of bovine pancreas trypsin and chymotrypsin were measured at different pHs and temperatures. The optimal pH for the hydrolysis of whey proteins was 9.0 for both enzymes. Optima temperatures were 60ºC for trypsin, and 50ºC for chymotrypsin. Trypsin exhibited typical Michaelis-Menten behavior, but chymotrypsin did not. Electrophoretic analysis showed that neither trypsin nor chymotrypsin alone hydrolyzed whey proteins in less than three hours. Hydrolysis rates of -lactalbumin by trypsin, and of bovine serum albumin by chymotrypsin were low. When these enzymes were combined, however, all protein fractions were attacked and rates of hydrolysis were enhanced by one order of magnitude. The addition of carboxypeptidase A to the others enzymes did not improve the process yield.

Electron transfer precedes ATP hydrolysis during nitrogenase catalysis.

Science.gov (United States)

Duval, Simon; Danyal, Karamatullah; Shaw, Sudipta; Lytle, Anna K; Dean, Dennis R; Hoffman, Brian M; Antony, Edwin; Seefeldt, Lance C

2013-10-08

The biological reduction of N2 to NH3 catalyzed by Mo-dependent nitrogenase requires at least eight rounds of a complex cycle of events associated with ATP-driven electron transfer (ET) from the Fe protein to the catalytic MoFe protein, with each ET coupled to the hydrolysis of two ATP molecules. Although steps within this cycle have been studied for decades, the nature of the coupling between ATP hydrolysis and ET, in particular the order of ET and ATP hydrolysis, has been elusive. Here, we have measured first-order rate constants for each key step in the reaction sequence, including direct measurement of the ATP hydrolysis rate constant: kATP = 70 s(-1), 25 °C. Comparison of the rate constants establishes that the reaction sequence involves four sequential steps: (i) conformationally gated ET (kET = 140 s(-1), 25 °C), (ii) ATP hydrolysis (kATP = 70 s(-1), 25 °C), (iii) Phosphate release (kPi = 16 s(-1), 25 °C), and (iv) Fe protein dissociation from the MoFe protein (kdiss = 6 s(-1), 25 °C). These findings allow completion of the thermodynamic cycle undergone by the Fe protein, showing that the energy of ATP binding and protein-protein association drive ET, with subsequent ATP hydrolysis and Pi release causing dissociation of the complex between the Fe(ox)(ADP)2 protein and the reduced MoFe protein.

Electron transfer precedes ATP hydrolysis during nitrogenase catalysis

Science.gov (United States)

Duval, Simon; Danyal, Karamatullah; Shaw, Sudipta; Lytle, Anna K.; Dean, Dennis R.; Hoffman, Brian M.; Antony, Edwin; Seefeldt, Lance C.

2013-01-01

The biological reduction of N2 to NH3 catalyzed by Mo-dependent nitrogenase requires at least eight rounds of a complex cycle of events associated with ATP-driven electron transfer (ET) from the Fe protein to the catalytic MoFe protein, with each ET coupled to the hydrolysis of two ATP molecules. Although steps within this cycle have been studied for decades, the nature of the coupling between ATP hydrolysis and ET, in particular the order of ET and ATP hydrolysis, has been elusive. Here, we have measured first-order rate constants for each key step in the reaction sequence, including direct measurement of the ATP hydrolysis rate constant: kATP = 70 s−1, 25 °C. Comparison of the rate constants establishes that the reaction sequence involves four sequential steps: (i) conformationally gated ET (kET = 140 s−1, 25 °C), (ii) ATP hydrolysis (kATP = 70 s−1, 25 °C), (iii) Phosphate release (kPi = 16 s−1, 25 °C), and (iv) Fe protein dissociation from the MoFe protein (kdiss = 6 s−1, 25 °C). These findings allow completion of the thermodynamic cycle undergone by the Fe protein, showing that the energy of ATP binding and protein–protein association drive ET, with subsequent ATP hydrolysis and Pi release causing dissociation of the complex between the Feox(ADP)2 protein and the reduced MoFe protein. PMID:24062462

Simultaneous microwave-assisted synthesis, characterization, thermal stability, and antimicrobial activity of cellulose/AgCl nanocomposites

International Nuclear Information System (INIS)

Li, Shu-Ming; Fu, Lian-Hua; Ma, Ming-Guo; Zhu, Jie-Fang; Sun, Run-Cang; Xu, Feng

2012-01-01

By means of a simultaneous microwave-assisted method and a simple chemical reaction, cellulose/AgCl nanocomposites have been successfully synthesized using cellulose solution and AgNO 3 in N,N-dimethylacetamide (DMAc) solvent. The cellulose solution was firstly prepared by the dissolution of the microcrystalline cellulose and lithium chloride (LiCl) in DMAc. DMAc acts as both a solvent and a microwave absorber. LiCl was used as the reactant to fabricate AgCl crystals. The effects of the heating time and heating temperature on the products were studied. This method is based on the simultaneous formation of AgCl nanoparticles and precipitation of the cellulose, leading to a homogeneous distribution of AgCl nanoparticles in the cellulose matrix. The experimental results confirmed the formation of cellulose/AgCl nanocomposites with high-purity, good thermal stability and antimicrobial activity. This rapid, green and environmentally friendly microwave-assisted method opens a new window to the high value-added applications of biomass. -- Highlights: ► Cellulose/AgCl nanocomposites have been synthesized by microwave method. ► Effect of heating temperature on the nanocomposites was researched. ► Thermal stability of the nanocomposites was investigated. ► Cellulose/AgCl nanocomposites had good antimicrobial activity. ► This method is based on the simultaneous formation of AgCl and cellulose.

Hydrolysis of metal ions. Vol. 1 and 2

Energy Technology Data Exchange (ETDEWEB)

Brown, Paul L. [Geochem Australia, Kiama, NSW (Australia); Ekberg, Christian [Chalmers Univ. of Technology, Goeteborg (Sweden). Nuclear Chemistry/Industrial Materials Recycling

2016-07-01

Filling the need for a comprehensive treatment that covers the theory, methods and the different types of metal ion complexes with water (hydrolysis), this handbook and ready reference is authored by a nuclear chemist from academia and an industrial geochemist. The book includes both cation and anion complexes, and approaches the topic of metal ion hydrolysis by first covering the background, before proceeding with an overview of the dissociation of water and then all different metal-water hydrolysis complexes and compounds. A must-have for scientists in academia and industry working on this interdisciplinary topic.

Direct injection of superheated steam for continuous hydrolysis reaction

KAUST Repository

Wang, Weicheng

2012-09-01

The primary intent for previous continuous hydrolysis studies was to minimize the reaction temperature and reaction time. In this work, hydrolysis is the first step of a proprietary chemical process to convert lipids to sustainable, drop-in replacements for petroleum based fuels. To improve the economics of the process, attention is now focused on optimizing the energy efficiency of the process, maximizing the reaction rate, and improving the recovery of the glycerol by-product. A laboratory-scale reactor system has been designed and built with this goal in mind.Sweet water (water with glycerol from the hydrolysis reaction) is routed to a distillation column and heated above the boiling point of water at the reaction pressure. The steam pressure allows the steam to return to the reactor without pumping. Direct injection of steam into the hydrolysis reactor is shown to provide favorable equilibrium conditions resulting in a high quality of FFA product and rapid reaction rate, even without preheating the inlet water and oil and with lower reactor temperatures and lower fresh water demand. The high enthalpy of the steam provides energy for the hydrolysis reaction. Steam injection offers enhanced conditions for continuous hydrolysis of triglycerides to high-purity streams of FFA and glycerol. © 2012 Elsevier B.V.

Linking Hydrolysis Performance to Trichoderma reesei Cellulolytic Enzyme Profile

DEFF Research Database (Denmark)

Lehmann, Linda Olkjær; Petersen, Nanna; I. Jørgensen, Christian

2016-01-01

Trichoderma reesei expresses a large number of enzymes involved in lignocellulose hydrolysis and the mechanism of how these enzymes work together is too complex to study by traditional methods, e.g. by spiking with single enzymes and monitoring hydrolysis performance. In this study a multivariate...... approach, partial least squares regression, was used to see if it could help explain the correlation between enzyme profile and hydrolysis performance. Diverse enzyme mixtures were produced by Trichoderma reesei Rut-C30 by exploiting various fermentation conditions and used for hydrolysis of washed...

Direct synthesis of Sb{sub 2}O{sub 3} nanoparticles via hydrolysis-precipitation method

Energy Technology Data Exchange (ETDEWEB)

Hu, Yuehua [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhang, Huihui [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China); Yang, Huaming [Department of Inorganic Materials, School of Resources Processing and Bioengineering, Central South University, Changsha 410083 (China)]. E-mail: hmyang@mail.csu.edu.cn

2007-01-31

Antimony oxide (Sb{sub 2}O{sub 3}) has wide applications as conductive materials, effective catalyst, functional filler and optical materials. Nanocrystalline Sb{sub 2}O{sub 3} has been successfully synthesized by hydrolysis-precipitation method. The samples were characterized by means of transmission electron microscopy (TEM), high-resolution TEM (HRTEM) images, X-ray diffraction (XRD) and differential thermal analysis (DTA). The average crystal size of the Sb{sub 2}O{sub 3} nanoparticles increases with increasing the reaction temperature. TEM image of the as-synthesized nanocrystalline Sb{sub 2}O{sub 3} shows rod-like structure. HRTEM images indicate a preferred directional growth of the Sb{sub 2}O{sub 3} nanoparticles. The electrochemical behaviors of Sb{sub 2}O{sub 3} electrodes have been primarily investigated by cyclic voltammetry (CV) in lithium hexafluorophosphate (LiPF{sub 6}) solution. Sb{sub 2}O{sub 3} nanocrystallite phase has prominent effect on the electrochemical properties. The results indicate that nanocrystalline Sb{sub 2}O{sub 3} synthesized by hydrolysis-precipitation method shows potential application in the field of the electrode materials.

Hydrolysis rates of domestic wastewater sludge using biochemical ...

African Journals Online (AJOL)

Domestic wastewater treatment can be improved by reducing energy consumption and increasing carbon recovery, which can be achieved using anaerobic digestion of sludge with methane recovery at ambient temperature. Hydrolysis can be a limiting step in anaerobic digestion, and characterisation of hydrolysis rates ...

Kinetic study of sphingomyelin hydrolysis for ceramide production

DEFF Research Database (Denmark)

Zhang, Long; Hellgren, Lars; Xu, Xuebing

2008-01-01

in cosmetic and pharmaceutical industries such as in hair and skin care products. The enzymatic hydrolysis of sphingomyelin has been proved to be a feasible method to produce ceramide. The kinetic performance of sphingomyelin hydrolysis in the optimal two-phase (water:organic solvent) reaction system...

Combined alkaline hydrolysis and ultrasound-assisted extraction for the release of nonextractable phenolics from cauliflower (Brassica oleracea var. botrytis) waste.

Science.gov (United States)

Gonzales, Gerard Bryan; Smagghe, Guy; Raes, Katleen; Van Camp, John

2014-04-16

Cauliflower waste contains high amounts phenolic compounds, but conventional solvent extraction misses high amounts of nonextractable phenolics (NEP), which may contribute more to the valorization of these waste streams. In this study, the NEP content and composition of cauliflower waste were investigated. The ability of alkaline hydrolysis, sonication, and their combination to release NEP was assessed. Alkaline hydrolysis with sonication was found to extract the highest NEP content (7.3 ± 0.17 mg gallic acid equivalents (GAE)/g dry waste), which was higher than the extractable fraction. The highest yield was obtained after treatment of 2 M NaOH at 60 °C for 30 min of sonication. Quantification and identification were done using U(H)PLC-DAD and U(H)PLC-ESI-MS(E). Kaempferol and quercetin glucosides along with several phenolic acids were found. The results of the study show that there are higher amounts of valuable health-promoting compounds from cauliflower waste than what is currently described in the literature.

Enhanced hydrolysis of cellulose hydrogels by morphological modification.

Science.gov (United States)

Alfassi, Gilad; Rein, Dmitry M; Cohen, Yachin

2017-11-01

Cellulose is one of the most abundant bio-renewable materials on earth, yet the potential of cellulosic bio-fuels is not fully exploited, primarily due to the high costs of conversion. Hydrogel particles of regenerated cellulose constitute a useful substrate for enzymatic hydrolysis, due to their porous and amorphous structure. This article describes the influence of several structural aspects of the cellulose hydrogel on its hydrolysis. The hydrogel density was shown to be directly proportional to the cellulose concentration in the initial solution, thus affecting its hydrolysis rate. Using high-resolution scanning electron microscopy, we show that the hydrogel particles in aqueous suspension exhibit a dense external surface layer and a more porous internal network. Elimination of the external surface layer accelerated the hydrolysis rate by up to sixfold and rendered the process nearly independent of cellulose concentration. These findings may be of practical relevance to saccharification processing costs, by reducing required solvent quantities and enzyme load.

Energy dashboard for real-time evaluation of a heat pump assisted solar thermal system

Science.gov (United States)

Lotz, David Allen

The emergence of net-zero energy buildings, buildings that generate at least as much energy as they consume, has lead to greater use of renewable energy sources such as solar thermal energy. One example is a heat pump assisted solar thermal system, which uses solar thermal collectors with an electrical heat pump backup to supply space heating and domestic hot water. The complexity of such a system can be somewhat problematic for monitoring and maintaining a high level of performance. Therefore, an energy dashboard was developed to provide comprehensive and user friendly performance metrics for a solar heat pump system. Once developed, the energy dashboard was tested over a two-week period in order to determine the functionality of the dashboard program as well as the performance of the heating system itself. The results showed the importance of a user friendly display and how each metric could be used to better maintain and evaluate an energy system. In particular, Energy Factor (EF), which is the ratio of output energy (collected energy) to input energy (consumed energy), was a key metric for summarizing the performance of the heating system. Furthermore, the average EF of the solar heat pump system was 2.29, indicating an efficiency significantly higher than traditional electrical heating systems.

Effect of protonation on the mechanism of phosphate monoester hydrolysis and comparison with the hydrolysis of nucleoside triphosphate in biomolecular motors.

Science.gov (United States)

Hassan, Hammad Ali; Rani, Sadaf; Fatima, Tabeer; Kiani, Farooq Ahmad; Fischer, Stefan

2017-11-01

Hydrolysis of phosphate groups is a crucial reaction in living cells. It involves the breaking of two strong bonds, i.e. the O a H bond of the attacking water molecule, and the PO l bond of the substrate (O a and O l stand for attacking and leaving oxygen atoms). Mechanism of the hydrolysis reaction can proceed either by a concurrent or a sequential mechanism. In the concurrent mechanism, the breaking of O a H and PO l bonds occurs simultaneously, whereas in the sequential mechanism, the O a H and PO l bonds break at different stages of the reaction. To understand how protonation affects the mechanism of hydrolysis of phosphate monoester, we have studied the mechanism of hydrolysis of protonated and deprotonated phosphate monoester at M06-2X/6-311+G**//M06-2X/6-31+G*+ZPE level of theory (where ZPE stands for zero point energy). Our calculations show that in both protonated and deprotonated cases, the breaking of the water O a H bond occurs before the breaking of the PO l bond. Because the two events are not separated by a stable intermediate, the mechanism can be categorized as semi-concurrent. The overall energy barrier is 41kcalmol -1 in the unprotonated case. Most (5/6th) of this is due to the initial breaking of the water O a H bond. This component is lowered from 34 to 25kcalmol -1 by adding one proton to the phosphate. The rest of the overall energy barrier comes from the subsequent breaking of the PO l bond and is not sensitive to protonation. This is consistent with previous findings about the effect of triphosphate protonation on the hydrolysis, where the equivalent protonation (on the γ-phosphate) was seen to lower the barrier of breaking the water O a H bond and to have little effect on the PO l bond breaking. Hydrolysis pathways of phosphate monoester with initial breaking of the PO l bond could not be found here. This is because the leaving group in phosphate monoester cannot be protonated, unlike in triphosphate hydrolysis, where protonation of the �

Re-evaluating the kinetics of ATP hydrolysis during initiation of DNA sliding by Type III restriction enzymes.

Science.gov (United States)

Tóth, Júlia; Bollins, Jack; Szczelkun, Mark D

2015-12-15

DNA cleavage by the Type III restriction enzymes requires long-range protein communication between recognition sites facilitated by thermally-driven 1D diffusion. This 'DNA sliding' is initiated by hydrolysis of multiple ATPs catalysed by a helicase-like domain. Two distinct ATPase phases were observed using short oligoduplex substrates; the rapid consumption of ∼10 ATPs coupled to a protein conformation switch followed by a slower phase, the duration of which was dictated by the rate of dissociation from the recognition site. Here, we show that the second ATPase phase is both variable and only observable when DNA ends are proximal to the recognition site. On DNA with sites more distant from the ends, a single ATPase phase coupled to the conformation switch was observed and subsequent site dissociation required little or no further ATP hydrolysis. The overall DNA dissociation kinetics (encompassing site release, DNA sliding and escape via a DNA end) were not influenced by the second phase. Although the data simplifies the ATP hydrolysis scheme for Type III restriction enzymes, questions remain as to why multiple ATPs are hydrolysed to prepare for DNA sliding. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Ultrasound Pretreatment as an Useful Tool to Enhance Egg White Protein Hydrolysis: Kinetics, Reaction Model, and Thermodinamics.

Science.gov (United States)

Jovanović, Jelena R; Stefanović, Andrea B; Šekuljica, Nataša Ž; Tanasković, Sonja M Jakovetić; Dojčinović, Marina B; Bugarski, Branko M; Knežević-Jugović, Zorica D

2016-09-28

The impact of ultrasound waves generated by probe-type sonicator and ultrasound cleaning bath on egg white protein susceptibility to hydrolysis by alcalase compared to both thermal pretreatment and conventional enzymatic hydrolysis was quantitatively investigated. A series of hydrolytic reactions was carried out in a stirred tank reactor at different substrate concentrations, enzyme concentrations, and temperatures using untreated, and pretreated egg white proteins (EWPs). The kinetic model based on substrate inhibition and second-order enzyme deactivation successfully predicts the experimental behavior providing an effective tool for comparison and optimization. The ultrasound pretreatments appear to greatly improve the enzymatic hydrolysis of EWPs under different conditions when compare to other methods. The apparent reaction rate constants for proteolysis (k 2 ) are 0.009, 0.011, 0.053, and 0.045 min -1 for untreated EWPs, and those pretreated with heat, probe-type sonicator, and ultrasound cleaning bath technologies, respectively. The ultrasound pretreatment also decreases hydrolysis activation (E a ) and enzyme deactivation (E d ) energy, enthalpy (ΔH), and entropy (ΔS) of activation and for the probe-type sonication this decrease is 61.7%, 61.6%, 63.6%, and 32.2%, respectively, but ultrasound has little change in Gibbs free energy value in the temperature range of 318 to 338 K. The content of sulfhydryl groups and ζ potential show a significant increase (P < 0.05) for both applied ultrasound pretreatments and the reduction of particle size distribution are achieved, providing some evidence that the ultrasound causes EWP structural changes affecting the proteolysis rate. © 2016 Institute of Food Technologists®

Biotransformation of 5-hydroxy-methylfurfural into 2,5-furan-dicarboxylic acid by bacterial isolate using thermal acid algal hydrolysate.

Science.gov (United States)

Yang, Chu-Fang; Huang, Ci-Ruei

2016-08-01

Thermal acid hydrolysis is often used to deal with lignocellulosic biomasses, but 5-hydroxy-methylfurfural (5-HMF) formed during hydrolysis deeply influences downstream fermentation. 2,5-Furan-dicarboxylic acid (FDCA), which is in the list of future important biomass platform molecules can be obtained using 5-HMF biotransformation. Based on the connection between 5-HMF removal in acid hydrolysate and FDCA production, the optimum thermal acid hydrolysis condition for macroalgae Chaetomorpha linum was established. Potential microbes capable of transforming 5-HMF into FDCA were isolated and characterized under various parameters and inoculated into algal hydrolysate to perform 5-HMF biotransformation. The optimum hydrolysis condition was to apply 0.5M HCl to treat 3% algal biomass under 121°C for 15min. Isolated Burkholderia cepacia H-2 could transform 2000mg/L 5-HMF at the initial pH of 7 at 28°C and 1276mg/L FDCA was received. Strain B. cepacia H-2 was suitable for treating the algal hydrolysate without dilution, receiving 989.5mg/L FDCA. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel process for synthesis of spherical nanocellulose by controlled hydrolysis of microcrystalline cellulose using anaerobic microbial consortium.

Science.gov (United States)

Satyamurthy, P; Vigneshwaran, N

2013-01-10

Degradation of cellulose by anaerobic microbial consortium is brought about either by an exocellular process or by secretion of extracellular enzymes. In this work, a novel route for synthesis of nanocellulose is described where in an anaerobic microbial consortium enriched for cellulase producers is used for hydrolysis. Microcrystalline cellulose derived from cotton fibers was subjected to controlled hydrolysis by the anaerobic microbial consortium and the resultant nanocellulose was purified by differential centrifugation technique. The nanocellulose had a bimodal size distribution (43±13 and 119±9 nm) as revealed by atomic force microscopy. A maximum nanocellulose yield of 12.3% was achieved in a span of 7 days. While the conventional process of nanocellulose preparation using 63.5% (w/w) sulfuric acid resulted in the formation of whisker shaped nanocellulose with surface modified by sulfation, controlled hydrolysis by anaerobic microbial consortium yielded spherical nanocellulose also referred to as nano crystalline cellulose (NCC) without any surface modification as evidenced from Fourier transform infrared spectroscopy. Also, it scores over chemo-mechanical production of nanofibrillated cellulose by consuming less energy due to enzyme (cellulase) assisted catalysis. This implies the scope for use of microbial prepared nanocellulose in drug delivery and bio-medical applications requiring bio-compatibility. Copyright © 2012 Elsevier Inc. All rights reserved.

Thermally assisted acoustofluidic separation of extracellular vesicles from cells

Science.gov (United States)

Mirtaheri, Elnaz; Dolatmoradi, Ata; Pimentel, Krystine; Bhansali, Shekhar; El-Zahab, Bilal

2018-02-01

Extracellular vesicles (EVs) have been gaining increasing attention given their role in communicating information between cells. Composition-based isolation of EVs is particularly of high significance as the proteomic and lipidomic characterization of their cargo could provide valuable clues to the role of EVs in mediating the biology of various conditions. This has, however, proved to be challenging as EVs, despite their abundance, are very small and difficult to be differentiated from the other constituents of host media. In addition, currently available methods like ultracentrifugation and filtration are cumbersome and capable of achieving mostly size-based separations. In this work, we demonstrate the possibility of separating submicron EV-like vesicles from cancer cells using a thermally-assisted acoustophoretic device. In a system composed of MCF-7 breast cancer cells spiked with two different types of same-size vesicles, composition-based isolation of vesicles was shown to be realizable through opposite focusing of the system's components at the node and antinodes of the overlaid ultrasonic standing wave. By proper choice of temperature in the microchannel, we were able to achieve separations with purities exceeding 93%. Furthermore, cells recovered from the channel were shown to be viable after the separation.

Hydrolysis of isocyanic acid on SCR catalysts

Energy Technology Data Exchange (ETDEWEB)

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

1999-08-01

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

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

Science.gov (United States)

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Starch hydrolysis modeling: application to fuel ethanol production.

Science.gov (United States)

Murthy, Ganti S; Johnston, David B; Rausch, Kent D; Tumbleson, M E; Singh, Vijay

2011-09-01

Efficiency of the starch hydrolysis in the dry grind corn process is a determining factor for overall conversion of starch to ethanol. A model, based on a molecular approach, was developed to simulate structure and hydrolysis of starch. Starch structure was modeled based on a cluster model of amylopectin. Enzymatic hydrolysis of amylose and amylopectin was modeled using a Monte Carlo simulation method. The model included the effects of process variables such as temperature, pH, enzyme activity and enzyme dose. Pure starches from wet milled waxy and high-amylose corn hybrids and ground yellow dent corn were hydrolyzed to validate the model. Standard deviations in the model predictions for glucose concentration and DE values after saccharification were less than ± 0.15% (w/v) and ± 0.35%, respectively. Correlation coefficients for model predictions and experimental values were 0.60 and 0.91 for liquefaction and 0.84 and 0.71 for saccharification of amylose and amylopectin, respectively. Model predictions for glucose (R2 = 0.69-0.79) and DP4+ (R2 = 0.8-0.68) were more accurate than the maltotriose and maltose for hydrolysis of high-amylose and waxy corn starch. For yellow dent corn, simulation predictions for glucose were accurate (R2 > 0.73) indicating that the model can be used to predict the glucose concentrations during starch hydrolysis.

Structural stability of hydrogenated amorphous carbon overcoats used in heat-assisted magnetic recording investigated by rapid thermal annealing

KAUST Repository

Wang, N.; Komvopoulos, K.; Rose, F.; Marchon, B.

2013-01-01

Ultrathin amorphous carbon (a-C) films are extensively used as protective overcoats of magnetic recording media. Increasing demands for even higher storage densities have necessitated the development of new storage technologies, such as heat-assisted magnetic recording (HAMR), which uses laser-assisted heating to record data on high-stability media that can store single bits in extremely small areas (∼1 Tbit/in.2). Because HAMR relies on locally changing the coercivity of the magnetic medium by raising the temperature above the Curie temperature for data to be stored by the magnetic write field, it raises a concern about the structural stability of the ultrathin a-C film. In this study, rapid thermal annealing (RTA) experiments were performed to examine the thermal stability of ultrathin hydrogenated amorphous carbon (a-C:H) films deposited by plasma-enhanced chemical vapor deposition. Structural changes in the a-C:H films caused by RTA were investigated by x-ray photoelectron spectroscopy, Raman spectroscopy, x-ray reflectivity, and conductive atomic force microscopy. The results show that the films exhibit thermal stability up to a maximum temperature in the range of 400-450 °C. Heating above this critical temperature leads to hydrogen depletion and sp 2 clustering. The critical temperature determined by the results of this study represents an upper bound of the temperature rise due to laser heating in HAMR hard-disk drives and the Curie temperature of magnetic materials used in HAMR hard disks. © 2013 American Institute of Physics.

Direct injection of superheated steam for continuous hydrolysis reaction

KAUST Repository

Wang, Weicheng; Turner, Timothy L.; Roberts, William L.; Stikeleather, Larry F.

2012-01-01

The primary intent for previous continuous hydrolysis studies was to minimize the reaction temperature and reaction time. In this work, hydrolysis is the first step of a proprietary chemical process to convert lipids to sustainable, drop

Furfural production from fruit shells by acid-catalyzed hydrolysis

Energy Technology Data Exchange (ETDEWEB)

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

2006-01-21

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

Combined enzymatic hydrolysis and fermentation of hemicellulose to 2,3-butanediol

Energy Technology Data Exchange (ETDEWEB)

Yu, E.K.C.; Deschatelets, L.; Saddler, J.N.

1984-06-01

Hemicellulose-rich fractions from several agricultural residues were converted to 2,3-butanediol by a combined enzymatic hydrolysis and fermentation process. Culture filtrates from Trichoderma harzianum E58 were used to hydrolyze the substrates while Klebsiella pneumoniae fermented the liberated sugars to 2,3-butanediol. Approximately 50-60% of a 5% (w/v) xylan preparation could be hydrolyzed and quantitatively converted to 2,3-butanediol using this procedure. Although enzymatic hydrolysis was optimal at pH 5.0 and 50/sup 0/C, the combined hydrolysis and fermentation was most efficient at pH 6.5 and 30/sup 0/C. Combined hydrolysis and fermentation resulted in butanediol levels that were 20-40% higher than could be obtained with a separate hydrolysis and fermentation process. The hemicellulose-rich water-soluble fractions obtained from a variety of steam-exploded agricultural residues could be readily used by the combined hydrolysis and fermentation approach resulting in butanediol yields of 0.4-0.5 g/g of reducing sugar utilized.

Hydrolysis of diacylglycerols by lipoprotein lipase.

Science.gov (United States)

Morley, N H; Kuksis, A; Buchnea, D; Myher, J J

1975-05-10

Enantiomeric diacylglycerols were emulsified, mole for mole, with lyso(1-acyl) lecithin and were hydrolyzed with lipoprotein lipase in NH4Cl-beef serum albumin buffer at pH 8.6 after a brief incubation with delipidated rat serum. The enzyme was prepared from lyophilized and dialyzed bovine skim milk in a 4 percent solution. The course of hydrolysis for each set of enantiomers was determined by gas-liquid chromatography of the masses of the diacylglycerols remaining or monoacylglycerols released in the medium between 0 and 15 min. The majority of sets of sn-1,2- and 2,3-diacylglycerols, including an isotope-labeled true enantiomeric set which was assessed by mass spectrometry, demonstrated preference by the enzyme for lipolysis at position 1 but with less specificity than previously was shown in sn-triacylglycerol hydrolysis. The results preclude the possibility that the predominance of sn-2,3-diacylglycerol intermediates during triacylglycerol hydrolysis is due solely to a preferential breakdown of the 1,2-isomers and reinforce the conclusion that lipoprotein lipase is specific for position 1.

Heteropoly acid catalyzed hydrolysis of glycogen to glucose

International Nuclear Information System (INIS)

Klein, Miri; Pulidindi, Indra Neel; Perkas, Nina; Gedanken, Aharon

2015-01-01

Complete conversion of glycogen to glucose is achieved by using H 3 PW 12 O 40 ·nH 2 O (HPW) and H 4 SiW 12 O 40 ·nH 2 O (HSiW) as catalysts for the hydrolysis under optimized hydrothermal conditions (mass fraction of catalyst 2.4%, 373 K and 2 h reaction time). The reusability of the catalyst (HPW) was demonstrated. In addition to carrying out the glycogen hydrolysis in an autoclave, other novel methods such as microwave irradiation and sonication have also been investigated. At higher mass fraction of the heteropoly acids (10.5%), glycogen could be completely converted to glucose under microwave irradiation. Sonication of an aqueous solution of glycogen in the presence of HPW and HSiW also yielded glucose. Thus, heteropoly acids are efficient, environmentally friendly and reusable catalysts for the conversion of glycogen to glucose. - Highlights: • Hydrothermal, microwave and sonication based methods of hydrolysis. • Heteropoly acids are green catalysts for glycogen hydrolysis. • Glycogen from cyanobacteria is demonstrated as a potential feedstock for glucose

Acid hydrolysis of Biomass lignocellulose Onopordum nervosum Boiss

International Nuclear Information System (INIS)

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

1985-01-01

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

Analysis of environmental effect of hybrid solar-assisted desalination cycle in Sirdarya Thermal Power Plant, Uzbekistan

International Nuclear Information System (INIS)

Alikulov, Khusniddin; Xuan, Tran Dang; Higashi, Osamu; Nakagoshi, Nobukazu; Aminov, Zarif

2017-01-01

Highlights: • A hybrid solar-assisted desalination cycle was designed and stimulated. • Maximum of 21,064.00 kW effective solar heat can be achieved. • The use of parabolic-trough collectors in the Multi Effect Distillation is potential. • The cycle can be applied in other regions with high Direct Normal Irradiation. - Abstract: This study was to investigate possible reduction of fossil fuel consumption and carbon dioxide emission in one of energy sectors of Sirdarya Thermal Power Plant (TPP), Uzbekistan. A hybrid solar-assisted desalination cycle has been designed and simulated for partially supplying saturated steam with 200 °C, 8 bar, and 32 t/h parameters to a Multi Effect Distillation (MED) process in the Sirdarya Thermal Power Plant. The outcome of the parental design model stated that maximum, 21,064.00 kW effective solar heat can be achieved, which is equivalent to 31.76 t/h of saturated steam with 200 °C and 8 bar parameters. Total saved fossil fuel in each month proved that it is possible to reduce fossil fuel (heavy oil and natural gas) consumption with 59.64, 95.24, 389.96, and 298.26 tons during available Direct Normal Irradiation (DNI) by using parabolic-trough collectors. Moreover, the above-mentioned fossil fuel savings accounted for CO_2 reduction with amounts of 182.50, 255.46, 1045.87 & 799.96 tons per each consistent month. Findings proved that integration of parabolic-trough collectors into the MED process is feasible in terms of high DNI availability and demand for retrofitting old existing heat-consuming facilities in Sirdarya Thermal Power Plant. Besides, the cycle also can be applied in other regions of Uzbekistan with high DNI for generating solar heat. Therefore, conducted study is eligible to be applied on the research site by taking into account of sufficient meteorological data and required steam parameters.

Study on the technology of compound enzymatic hydrolysis of whole passion fruit

Science.gov (United States)

Yang, Yu-xia; Duan, Zhen-hua; Kang, Chao; Zhu, Xiang-hao; Li, Ding-jin

2017-12-01

Fresh Whole Passion Fruit was used as raw material, The enzymatic hydrolysis technology of Passion Fruit by Complex enzyme were studied, The effects of enzyme dosage, Enzyme ratio(cellulose: pectinase), pH, temperature and time on the hydrolysis were investigated by single-tests and orthogonal tests, the hydrolysis indicators of single-factor tests and orthogonal tests were juice yield. The optimal hydrolysis conditions of Passion Fruit by Complex enzyme were enzyme dosage 0.12%, Enzyme ratio 5:1, hydrolysis temperature 50°C, pH4.0 and time 3.5 h. Under such conditions, juice yield of Passion Fruit was 92.91%.

Radiation-induced degradation and subsequent hydrolysis of waste cellulose materials

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1979-01-01

The effect of γ-pre-irradiation of cellulose in cellulose containing waste plants was investigated through enzymatic and acidic hydrolysis reaction. Pre-irradiation of waste rice straw, chaff and saw dust accelerated the enzymatic hydrolysis by cellulase. Reducing sugar and glucose yields were higher with an increasing radiation dose in these materials. The required dose for effective acceleration of enzymatic hydrolysis was much reduced by the addition of chlorine during radiation. However, reducing sugar and glucose yields in the subsequent acidic hydrolysis of waste products decreased through pre-irradiation treatment. This was attributed to an acceleration effect of a secondary acidic decomposition of sugar to lower molecular weight-products through pre-irradiation. (author)

Radiation-induced degradation and subsequent hydrolysis of waste cellulose materials

Energy Technology Data Exchange (ETDEWEB)

Kumakura, M; Kaetsu, I [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment

1979-03-01

The effect of ..gamma..-pre-irradiation of cellulose in cellulose containing waste plants was investigated through enzymatic and acidic hydrolysis reaction. Pre-irradiation of waste rice straw, chaff and saw dust accelerated the enzymatic hydrolysis by cellulase. Reducing sugar and glucose yields were higher with an increasing radiation dose in these materials. The required dose for effective acceleration of enzymatic hydrolysis was much reduced by the addition of chlorine during radiation. However, reducing sugar and glucose yields in the subsequent acidic hydrolysis of waste products decreased through pre-irradiation treatment. This was attributed to an acceleration effect of a secondary acidic decomposition of sugar to lower molecular weight-products through pre-irradiation.

Radiation-induced degradation and subsequent hydrolysis of waste cellulose materials

Energy Technology Data Exchange (ETDEWEB)

Kamakura, M; Kaetsu, I

1979-03-01

The effect of gamma-pre-irradiation of cellulose in cellulose-containing waste plants was investigated through enzymatic and acidic hydrolysis reaction. Pre-irradiation of waste rice straw, chaff and saw dust accelerated the enzymatic hydrolysis by cellulase. Reducing sugar and glucose yields were higher with an increasing radiation dose in these materials. The required dose for effective acceleration of enzymatic hydrolysis was much reduced by the addition of chlorine during radiation. However, reducing sugar and glucose yields in the subsequent acidic hydrolysis of waste products decreased through pre-irradiation treatment. This was attributed to an acceleration effect of a secondary acidic decomposition of sugar to lower molecular weight-products through pre-irradiation.

Chemical analysis and base-promoted hydrolysis of locally ...

African Journals Online (AJOL)

Abstract. The study was on the chemical analysis and base- promoted hydrolysis of extracted shea nut fat. The local method of extraction of the shea nut oil was employed in comparison with literature report. A simple cold-process alkali hydrolysis of the shea nut oil was used in producing the soap. The chemical analysis of ...

Multivariate data analysis of enzyme production for hydrolysis purposes

DEFF Research Database (Denmark)

Schmidt, A.S.; Suhr, K.I.

1999-01-01

of the structure in the data - possibly combined with analysis of variance (ANOVA). Partial least squares regression (PLSR) showed a clear connection between the two differentdata matrices (the fermentation variables and the hydrolysis variables). Hence, PLSR was suitable for prediction purposes. The hydrolysis...

Research and determination of process parameters of milk lactose hydrolysis

OpenAIRE

Калинина, Елена Дмитриевна; Коваленко, Александр Владимирович

2014-01-01

The researches of enzymatic milk lactose hydrolysis by using the β - galactosidase enzyme are given in the paper. For carrying out a lactose hydrolysis, two β-galactosidase enzyme preparations GODO-YNL2 and Neolactase are offered. For setting lactose hydrolysis parameters, the influence of a pH medium, temperature, enzyme preparation doses, the duration of hydrolyzing the milk lactose affected by the β- galactosidase enzyme preparations, was studied. In terms of effectiveness, adaptability an...

Hydrolysis of the amorphous cellulose in cotton-based paper.

Science.gov (United States)

Stephens, Catherine H; Whitmore, Paul M; Morris, Hannah R; Bier, Mark E

2008-04-01

Hydrolysis of cellulose in Whatman no. 42 cotton-based paper was studied using gel permeation chromatography (GPC), electrospray ionization-mass spectrometry (ESI-MS), and uniaxial tensile testing to understand the course and kinetics of the reaction. GPC results suggested that scission reactions passed through three stages. Additionally, the evolution of soluble oligomers in the ESI-MS data and the steady course of strength loss showed that the hydrolysis reaction occurred at a constant rate. These findings are explained with a more detailed description of the cellulose hydrolysis, which includes multiple chain scissions on amorphous segments. The breaks occur with increasing frequency near the ends of amorphous segments, where chains protrude from crystalline domains. Oligomers unattached to crystalline domains are eventually created. Late-stage reactions near the ends of amorphous segments produce a kinetic behavior that falsely suggests that hydrolysis had ceased. Monte Carlo simulations of cellulose degradation corroborated the experimental findings.

Synthesis of supermacroporous cryogel for bioreactors continuous starch hydrolysis.

Science.gov (United States)

Guilherme, Ederson Paulo Xavier; de Oliveira, Jocilane Pereira; de Carvalho, Lorendane Millena; Brandi, Igor Viana; Santos, Sérgio Henrique Sousa; de Carvalho, Gleidson Giordano Pinto; Cota, Junio; Mara Aparecida de Carvalho, Bruna

2017-11-01

A bioreactor was built by means of immobilizing alpha-amylase from Aspergillus oryzae by encapsulation, through cryopolymerization of acrylamide monomers for the continuous starch hydrolysis. The starch hydrolysis was evaluated regarding pH, the concentration of immobilized amylase on cryogel, the concentration of starch solution and temperature. The maximum value for starch hydrolysis was achieved at pH 5.0, concentration of immobilized enzyme 111.44 mg amylase /g cryogel , concentration of starch solution 45 g/L and temperature of 35°C. The immobilized enzyme showed a conversion ratio ranging from 68.2 to 97.37%, depending on the pH and temperature employed. Thus, our results suggest that the alpha-amylase from A. oryzae immobilized on cryogel monoliths represents a potential process for industrial production of maltose from starch hydrolysis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrolysis of aluminum dross material to achieve zero hazardous waste

International Nuclear Information System (INIS)

David, E.; Kopac, J.

2012-01-01

Highlights: ► The hydrolysis of aluminum dross in tap water generates pure hydrogen. ► Aluminum particles from dross are activated by mechanically milling technique. ► The process is completely greenhouse gases free and is cleanly to environment. ► Hydrolysis process leads to recycling of waste aluminum by hydrogen production. - Abstract: A simple method with high efficiency for generating high pure hydrogen by hydrolysis in tap water of highly activated aluminum dross is established. Aluminum dross is activated by mechanically milling to particles of about 45 μm. This leads to removal of surface layer of the aluminum particles and creation of a fresh chemically active metal surface. In contact with water the hydrolysis reaction takes place and hydrogen is released. In this process a Zero Waste concept is achieved because the other product of reaction is aluminum oxide hydroxide (AlOOH), which is nature-friendly and can be used to make high quality refractory or calcium aluminate cement. For comparison we also used pure aluminum powder and alkaline tap water solution (NaOH, KOH) at a ratio similar to that of aluminum dross content. The rates of hydrogen generated in hydrolysis reaction of pure aluminum and aluminum dross have been found to be similar. As a result of the experimental setup, a hydrogen generator was designed and assembled. Hydrogen volume generated by hydrolysis reaction was measured. The experimental results obtained reveal that aluminum dross could be economically recycled by hydrolysis process with achieving zero hazardous aluminum dross waste and hydrogen generation.

Mechanistic kinetic models of enzymatic cellulose hydrolysis-A review.

Science.gov (United States)

Jeoh, Tina; Cardona, Maria J; Karuna, Nardrapee; Mudinoor, Akshata R; Nill, Jennifer

2017-07-01

Bioconversion of lignocellulose forms the basis for renewable, advanced biofuels, and bioproducts. Mechanisms of hydrolysis of cellulose by cellulases have been actively studied for nearly 70 years with significant gains in understanding of the cellulolytic enzymes. Yet, a full mechanistic understanding of the hydrolysis reaction has been elusive. We present a review to highlight new insights gained since the most recent comprehensive review of cellulose hydrolysis kinetic models by Bansal et al. (2009) Biotechnol Adv 27:833-848. Recent models have taken a two-pronged approach to tackle the challenge of modeling the complex heterogeneous reaction-an enzyme-centric modeling approach centered on the molecularity of the cellulase-cellulose interactions to examine rate limiting elementary steps and a substrate-centric modeling approach aimed at capturing the limiting property of the insoluble cellulose substrate. Collectively, modeling results suggest that at the molecular-scale, how rapidly cellulases can bind productively (complexation) and release from cellulose (decomplexation) is limiting, while the overall hydrolysis rate is largely insensitive to the catalytic rate constant. The surface area of the insoluble substrate and the degrees of polymerization of the cellulose molecules in the reaction both limit initial hydrolysis rates only. Neither enzyme-centric models nor substrate-centric models can consistently capture hydrolysis time course at extended reaction times. Thus, questions of the true reaction limiting factors at extended reaction times and the role of complexation and decomplexation in rate limitation remain unresolved. Biotechnol. Bioeng. 2017;114: 1369-1385. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Two step novel hydrogen system using additives to enhance hydrogen release from the hydrolysis of alane and activated aluminum

Science.gov (United States)

Zidan, Ragaiy; Teprovich, Joseph A.; Motyka, Theodore

2015-12-01

A system for the generation of hydrogen for use in portable power systems is set forth utilizing a two-step process that involves the thermal decomposition of AlH.sub.3 (10 wt % H.sub.2) followed by the hydrolysis of the activated aluminum (Al*) byproduct to release additional H.sub.2. Additionally, a process in which water is added directly without prior history to the AlH.sub.3:PA composite is also disclosed.

The omnipresent water fern

NARCIS (Netherlands)

Nierop, K.G.J.; Speelman, E.N.; de Leeuw, J.W.; Reichart, G.J.

2011-01-01

Several studies have reported the presence of large amounts of lignin in ubiquitously occurring species of the freshwater fern Azolla. Molecular analysis using flash pyrolysis and thermally assisted hydrolysis and methylation shows, however, that neither the leaves nor the roots of Azolla contain

The omnipresent water fern Azolla caroliniana does not contain lignin

NARCIS (Netherlands)

Nierop, K.G.J.; Speelman, E.N.; Leeuw, J.W. de; Reichart, G.-J.

2011-01-01

Several studies have reported the presence of large amounts of lignin in ubiquitously occurring species of the freshwater fern Azolla. Molecular analysis using flash pyrolysis and thermally assisted hydrolysis and methylation shows, however, that neither the leaves nor the roots of Azolla contain

Building automation: Photovoltaic assisted thermal comfort management system for energy saving

International Nuclear Information System (INIS)

Khan, M Reyasudin Basir; Jidin, Razali; Shaaya, Sharifah Azwa; Pasupuleti, Jagadeesh

2013-01-01

Building automation plays an important key role in the means to reduce building energy consumption and to provide comfort for building occupants. It is often that air conditioning system operating features ignored in building automation which can result in thermal discomfort among building occupants. Most automation system for building is expensive and incurs high maintenance cost. Such system also does not support electricity demand side management system such as load shifting. This paper discusses on centralized monitoring system for room temperature and photovoltaic (PV) output for feasibility study of PV assisted air conditioning system in small office buildings. The architecture of the system consists of PV modules and sensor nodes located at each room. Wireless sensor network technology (WSN) been used for data transmission. The data from temperature sensors and PV modules transmitted to the host personal computer (PC) wirelessly using Zigbee modules. Microcontroller based USB data acquisition device used to receive data from sensor nodes and displays the data on PC.

Building automation: Photovoltaic assisted thermal comfort management system for energy saving

Science.gov (United States)

Reyasudin Basir Khan, M.; Jidin, Razali; Pasupuleti, Jagadeesh; Azwa Shaaya, Sharifah

2013-06-01

Building automation plays an important key role in the means to reduce building energy consumption and to provide comfort for building occupants. It is often that air conditioning system operating features ignored in building automation which can result in thermal discomfort among building occupants. Most automation system for building is expensive and incurs high maintenance cost. Such system also does not support electricity demand side management system such as load shifting. This paper discusses on centralized monitoring system for room temperature and photovoltaic (PV) output for feasibility study of PV assisted air conditioning system in small office buildings. The architecture of the system consists of PV modules and sensor nodes located at each room. Wireless sensor network technology (WSN) been used for data transmission. The data from temperature sensors and PV modules transmitted to the host personal computer (PC) wirelessly using Zigbee modules. Microcontroller based USB data acquisition device used to receive data from sensor nodes and displays the data on PC.

Optimization of dilute acid hydrolysis of Enteromorpha

Science.gov (United States)

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.

Hydrolysis of TBF and TiAP in presence of zirconium

International Nuclear Information System (INIS)

Vladimirova, M.V.; Kulikov, I.A.; Kuprij, A.A.

1992-01-01

Acid hydrolysis of organic solutions of tributyl phosphate (TBP) and tri-iso-amylphosphate (TiAP) in n-paraffin diluent in the presence of zirconium (0.025-0.1 mole/l) at nitric acid concentration of 0.3-1 mole/l is studied. Hydrolysis of extractants in a two-phase system, modelling conditions of spent fuel reprocessing and consisting of 1.1 mole/l TAP, 3 mole/l nitric acid at zirconium concentration in water phase 0.05-0.11 mole/l, at water-organic phase ratio 10:1 and at 60 deg C is also studied. Constants of TAP hydrolysis in organic and water phases are determined. Mechanism of increasing the TAP hydrolysis rate in zirconium presence is discussed. 5 refs., 2 figs., 5 tabs

Enzymatic hydrolysis of pretreated barley and wheat straw

DEFF Research Database (Denmark)

Rosgaard, Lisa

2007-01-01

. The work involved evaluation of 1) possible ways to increase the glucose release from the commercial cellulase product Celluclast by boosting with other enzyme activities to increase the enzymatic hydrolysis, 2) comparing differently pretreated feedstock substrates and 3) evaluating a fed-batch substrate...... mixture resulted in a glucose release corresponding to ~84 % of the glucose release from Celluclast. It was therefore suggested that other enzyme activities than the 4 four main cellulase activities in Celluclast are necessary for optimal hydrolysis of lignocellulose. Even though Celluclast...... is a multicomponent cellulase mixture, there are still possibilities for further improvement in terms of providing the most efficient cellulase mixture for lignocellulose hydrolysis. It was shown that substrates evaluated all had some residual hemicellulose in the solid cellulose fraction after pretreatment...

Base hydrolysis and hydrothermal processing of PBX-9404

International Nuclear Information System (INIS)

Flesner, R.L.; Spontarelli, T.; Dell'Orco, P.C.; Sanchez, J.A.

1994-01-01

Base hydrolysis in combination with hydrothermal processing has been proposed as an environmentally acceptable alternative to open burning/open detonation for degradation and destruction of high explosives. In this report, the authors examine gaseous and aqueous products of base hydrolysis of the HMX-based plastic bonded explosive, PBX-9404. They also examined products from the subsequent hydrothermal treatment of the base hydrolysate. The gases produced from hydrolysis of PBX-9404 are ammonia, nitrous oxide, and nitrogen. Major aqueous products are sodium formate, acetate, nitrate, and nitrite, but not all carbon products have been identified. Hydrothermal processing of base hydrolysate destroyed up to 98% of the organic carbon in solution, and higher destruction efficiencies are possible. Major gas products detected from hydrothermal processing were nitrogen and nitrous oxide

The optimization of soybean oil hydrolysis reaction research

International Nuclear Information System (INIS)

Hasnisa Hashim; Jumat Salimon

2008-01-01

The hydrolysis reaction of soybean oil was optimized. The concentration effect of ethanolic alkaline solution (KOH and NaOH) to the oil acidity was studied. The alkaline concentrations, reaction time and temperature factors was investigated during the optimization of the hydrolysis or saponification reaction. KOH solution of 1 M showed a good saponification activity which resulted oil acid value of 226.8 mg/ g compared to NaOH solution with acid value of 225.4 mg/ g for the same reaction. The optimum saponification reaction of soybean oil occurred at 60 degree Celsius in 30 minutes by using ethanolic KOH 1 M with acid value of 229.6 mg/ g. Composition of free fatty acid before and after hydrolysis were determined by using gas chromatography. (author)

Comparison of the economics of acid and enzymatic hydrolysis of newsprint

Energy Technology Data Exchange (ETDEWEB)

Grethlein, H E

1978-04-01

In order to compare the process economics of making glucose from cellulose, a plant design is presented using acid hydrolysis which can be compared with a published design using enzyme hydrolysis. A common design basis is used; namely, an input capacity of 885 ton/day newsprint with a common technique of cost estimation. The cost of making glucose is in the range of 1.75 to 2.45 cents/lb, depending on the slurry concentration fed to the reactor for the acid hydrolysis. This cost range is less than the published estimate of 5.2 cents/lb for enzymatic hydrolysis.

Ultrasound-Assisted Extraction and Characterization of Pectic Polysaccharide from Oriental Tobacco Leaves

International Nuclear Information System (INIS)

Liu, S.; Tian, Z.; Li, X.; He, P.; Xu, C.

2015-01-01

Ultrasound-assisted extraction (UAE) of pectic Polysaccharide from oriental tobacco leaves was studied by orthogonal matrix method (L9(3)4). Furthermore, the crude Polysaccharide was purified and two components (Fr-I and Fr-II) were obtained. FT-IR spectral analysis of the purified EPS revealed prominent characteristic groups. The monosaccharide composition analysis indicated the main composition between Fr-I and Fr-II was different. Furthermore, thermo gravimetric analysis (TGA) indicated the degradation temperature (Td) of the Fr-I (215 degree C) was higher than those of Fr-II (162 degree C). Detected by the pyrolysis GC/MS, though the main kinds of pyrolysis products from both Fr-I and Fr-II were similar, the larger amount of heterocycle and aromatic compounds liberated after hydrolysis of Fr-II. Finally, On the basis of the antioxidant activity test in vitro, Fr-II has stronger antioxidant activities than Fr-I. The thermal behavior and antioxidant activity might be attributed to the configuration of the sugar units and chemical compositions. (author)

Process development of starch hydrolysis using mixing characteristics of Taylor vortices.

Science.gov (United States)

Masuda, Hayato; Horie, Takafumi; Hubacz, Robert; Ohmura, Naoto; Shimoyamada, Makoto

2017-04-01

In food industries, enzymatic starch hydrolysis is an important process that consists of two steps: gelatinization and saccharification. One of the major difficulties in designing the starch hydrolysis process is the sharp change in its rheological properties. In this study, Taylor-Couette flow reactor was applied to continuous starch hydrolysis process. The concentration of reducing sugar produced via enzymatic hydrolysis was evaluated by varying operational variables: rotational speed of the inner cylinder, axial velocity (reaction time), amount of enzyme, and initial starch content in the slurry. When Taylor vortices were formed in the annular space, efficient hydrolysis occurred because Taylor vortices improved the mixing of gelatinized starch with enzyme. Furthermore, a modified inner cylinder was proposed, and its mixing performance was numerically investigated. The modified inner cylinder showed higher potential for enhanced mixing of gelatinized starch and the enzyme than the conventional cylinder.

Validation of lignocellulosic biomass carbohydrates determination via acid hydrolysis.

Science.gov (United States)

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. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermally assisted sensor for conformity assessment of biodiesel production

International Nuclear Information System (INIS)

Kawano, M S; Kamikawachi, R C; Fabris, J L; Muller, M

2015-01-01

Although biodiesel can be intentionally tampered with, impairing its quality, ineffective production processes may also result in a nonconforming final fuel. For an incomplete transesterification reaction, traces of alcohol (ethanol or methanol) or remaining raw material (vegetable oil or animal fats) may be harmful to consumers, the environment or to engines. Traditional methods for biodiesel assessment are complex, time consuming and expensive, leading to the need for the development of new and more versatile processes for quality control. This work describes a refractometric fibre optic based sensor that is thermally assisted, developed to quantify the remaining methanol or vegetable oil in biodiesel blends. The sensing relies on a long period grating to configure an in-fibre interferometer. A complete analytical routine is demonstrated for the sensor allowing the evaluation of the biodiesel blends without segregation of the components. The results show the sensor can determine the presence of oil or methanol in biodiesel with a concentration ranging from 0% to 10% v/v. The sensor presented a resolution and standard combined uncertainty of 0.013% v/v and 0.62% v/v for biodiesel–oil samples, and 0.007% v/v and 0.22% v/v for biodiesel–methanol samples, respectively. (paper)

Thermally assisted sensor for conformity assessment of biodiesel production

Science.gov (United States)

Kawano, M. S.; Kamikawachi, R. C.; Fabris, J. L.; Muller, M.

2015-02-01

Although biodiesel can be intentionally tampered with, impairing its quality, ineffective production processes may also result in a nonconforming final fuel. For an incomplete transesterification reaction, traces of alcohol (ethanol or methanol) or remaining raw material (vegetable oil or animal fats) may be harmful to consumers, the environment or to engines. Traditional methods for biodiesel assessment are complex, time consuming and expensive, leading to the need for the development of new and more versatile processes for quality control. This work describes a refractometric fibre optic based sensor that is thermally assisted, developed to quantify the remaining methanol or vegetable oil in biodiesel blends. The sensing relies on a long period grating to configure an in-fibre interferometer. A complete analytical routine is demonstrated for the sensor allowing the evaluation of the biodiesel blends without segregation of the components. The results show the sensor can determine the presence of oil or methanol in biodiesel with a concentration ranging from 0% to 10% v/v. The sensor presented a resolution and standard combined uncertainty of 0.013% v/v and 0.62% v/v for biodiesel-oil samples, and 0.007% v/v and 0.22% v/v for biodiesel-methanol samples, respectively.

Thermal modeling of head disk interface system in heat assisted magnetic recording

Energy Technology Data Exchange (ETDEWEB)

Vemuri, Sesha Hari; Seung Chung, Pil; Jhon, Myung S., E-mail: mj3a@andrew.cmu.edu [Department of Chemical Engineering and Data Storage Systems Center, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States); Min Kim, Hyung [Department of Mechanical System Engineering, Kyonggi University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

2014-05-07

A thorough understanding of the temperature profiles introduced by the heat assisted magnetic recording is required to maintain the hotspot at the desired location on the disk with minimal heat damage to other components. Here, we implement a transient mesoscale modeling methodology termed lattice Boltzmann method (LBM) for phonons (which are primary carriers of energy) in the thermal modeling of the head disk interface (HDI) components, namely, carbon overcoat (COC). The LBM can provide more accurate results compared to conventional Fourier methodology by capturing the nanoscale phenomena due to ballistic heat transfer. We examine the in-plane and out-of-plane heat transfer in the COC via analyzing the temperature profiles with a continuously focused and pulsed laser beam on a moving disk. Larger in-plane hotspot widening is observed in continuously focused laser beam compared to a pulsed laser. A pulsed laser surface develops steeper temperature gradients compared to continuous hotspot. Furthermore, out-of-plane heat transfer from the COC to the media is enhanced with a continuous laser beam then a pulsed laser, while the temperature takes around 140 fs to reach the bottom surface of the COC. Our study can lead to a realistic thermal model describing novel HDI material design criteria for the next generation of hard disk drives with ultra high recording densities.

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.

Science.gov (United States)

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

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

International Nuclear Information System (INIS)

Ait Si Mamar, S.; Hadjadj, A.

1990-01-01

The conversion of wheat straw agricultural cellulosic wastes to reducing sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution. (author)

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

Science.gov (United States)

Mamar, S. Ait Si; Hadjadj, A.

The conversion of wheat straw agricultural cellulosic wastes to reduning sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution.

Determining the hydrolysis of cations: A short overview

International Nuclear Information System (INIS)

Ekberg, Christian; Brown, Paul L.

2006-01-01

Full text: The hydrolysis of metal ions is the most fundamental aqueous chemistry. As soon as the metal is introduced to water, dissolution may take place and if the water is pure only hydrolysis reactions will take place. There are several methods used in the literature to determine the stability constants of these reactions, e.g. solvent extraction, potentiometric titrations, ion exchange and solubility measurements. Which one to select is not straight forward. All of them have pros and cons and different regions of applicability with respect to whether they are good for determining the initial hydrolysis or the later stages. Once the constants are determined it is important to assess the uncertainty in the determination. We point out tools to make this straight forward and traceable which is most important in scientific studies. (authors)

Improving Aspergillus carbonarius crude enzymes for lignocellulose hydrolysis

DEFF Research Database (Denmark)

Hansen, Gustav Hammerich

and single enzyme supplementation. Fungal strains were screened in order to determine crude enzyme extracts that could be supplemented as boosters of A. carbonarius own crude enzyme extract, when applied in lignocellulose hydrolysis. The fungi originated from different environmental niches, which all had...... for their potential in hydrolysis of wheat straw both by application of monocultures and by supplementing to crude enzymes of A. carbonarius. For the crude enzymes from solid cultivations there were eight isolates that showed synergistic interaction resulting in doubling and tripling of the glucose release in wheat...... straw hydrolysis. A completely different profile of synergy was observed for crude enzymes from liquid cultivations, as there were only three isolates that enhanced glucose release. Only one of these three isolates had shown synergistic effects when cultivated in a solid medium. The screening...

Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse

Directory of Open Access Journals (Sweden)

Carlos Martín

2012-01-01

Full Text Available The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by increasing surface area. For both materials, glucose concentrations increased with enzyme loading. On the other hand, enzyme loadings higher than 15 FPU/g did not result in any increase in the initial rate, since the excess of enzyme adsorbed onto the substrate restricted the diffusion process through the structure.

Thermally Stable Cellulose Nanocrystals toward High-Performance 2D and 3D Nanostructures.

Science.gov (United States)

Jia, Chao; Bian, Huiyang; Gao, Tingting; Jiang, Feng; Kierzewski, Iain Michael; Wang, Yilin; Yao, Yonggang; Chen, Liheng; Shao, Ziqiang; Zhu, J Y; Hu, Liangbing

2017-08-30

Cellulose nanomaterials have attracted much attention in a broad range of fields such as flexible electronics, tissue engineering, and 3D printing for their excellent mechanical strength and intriguing optical properties. Economic, sustainable, and eco-friendly production of cellulose nanomaterials with high thermal stability, however, remains a tremendous challenge. Here versatile cellulose nanocrystals (DM-OA-CNCs) are prepared through fully recyclable oxalic acid (OA) hydrolysis along with disk-milling (DM) pretreatment of bleached kraft eucalyptus pulp. Compared with the commonly used cellulose nanocrystals from sulfuric acid hydrolysis, DM-OA-CNCs show several advantages including large aspect ratio, carboxylated surface, and excellent thermal stability along with high yield. We also successfully demonstrate the fabrication of high-performance films and 3D-printed patterns using DM-OA-CNCs. The high-performance films with high transparency, ultralow haze, and excellent thermal stability have the great potential for applications in flexible electronic devices. The 3D-printed patterns with porous structures can be potentially applied in the field of tissue engineering as scaffolds.

SIMULTANEOUS PRETREATMENT OF LIGNOCELLULOSE AND HYDROLYSIS OF STARCH IN MIXTURES TO SUGARS

Directory of Open Access Journals (Sweden)

Hamzeh Hoseinpour

2010-11-01

Full Text Available Mixtures of starch and lignocelluloses are available in many industrial, agricultural, and municipal wastes and residuals. In this work, dilute sulfuric acid was used for simultaneous pretreatment of lignocellulose and hydrolysis of starch, to obtain a maximum amount of fermentable sugar after enzymatic hydrolysis with cellulase and β-glucosidase. The acid treatment was carried out at 70-150°C with 0-1% (v/v acid concentration and 5-15% (w/v solids concentration for 0-40 minutes. Under the optimum conditions, obtained at 130°C, 1% acid, and 7.5% solids loading for 30 min, the starch was almost completely converted to glucose. However, the acid treatment was not successful for efficient hydrolysis of pure cellulose. A mixture of pine softwood and potato as representatives of lignocellulosic and starch components, respectively, were treated at the optimum conditions for acid hydrolysis of starch. The dilute-acid treatment resulted in 1.2, 60.5, and 23.6% hydrolysis of glucan, xylan, and mannan of pine wood and 67% of potato starch to fermentable sugars. After the acid treatment, the solid residue of the mixture was subjected to enzymatic hydrolysis. The enzymatic hydrolysis under the optimum conditions resulted in conversion of 76% of the glucan in the treated softwood. Therefore, using acid treatment of the mixture is a promising process for pretreatment of wood in addition to the hydrolysis of starch.

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

Science.gov (United States)

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.

Preparations and mechanism of hydrolysis of ([8]annulene)actinide compounds

International Nuclear Information System (INIS)

Moore, R.M. Jr.

1985-07-01

The mechanism of hydrolysis for bis[8]annulene actinide and lanthanide complexes has been studied in detail. The uranium complex, uranocene, decomposes with good pseudo-first order kinetics (in uranocene) in 1 M degassed solutions of H 2 O in THF. Decomposition of a series of aryl-substituted uranocenes demonstrates that the hydrolysis rate is dependent on the electronic nature of the substituent (Hammett rho value = 2.1, r 2 = 0.999), with electron-withdrawing groups increasing the rate. When D 2 O is substituted for H 2 O, kinetic isotope effects of 8 to 14 are found for a variety of substituted uranocenes. These results suggest a pre-equilibrium involving approach of a water molecule to the central metal, followed by rate determining proton transfer to the eight membered ring and rapid decomposition to products. Each of the four protonations of the complex has a significant isotope effect. The product ratio of cyclooctatriene isomers formed in the hydrolysis varies, depending on the central metal of the complex. However, the general mechanism of hydrolysis, established for uranocene, can be extended to the hydrolysis and alcoholysis of all the [8]annulene complexes of the lanthanides and actinides

Impact of thermal processing on sulforaphane yield from broccoli ( Brassica oleracea L. ssp. italica).

Science.gov (United States)

Wang, Grace C; Farnham, Mark; Jeffery, Elizabeth H

2012-07-11

In broccoli, sulforaphane forms when the glucosinolate glucoraphanin is hydrolyzed by the endogenous plant thiohydrolase myrosinase. A myrosinase cofactor directs hydrolysis away from the formation of bioactive sulforaphane and toward an inactive product, sulforaphane nitrile. The cofactor is more heat sensitive than myrosinase, presenting an opportunity to preferentially direct hydrolysis toward sulforaphane formation through regulation of thermal processing. Four broccoli cultivars were microwave heated, boiled, or steamed for various lengths of time. Production of nitrile during hydrolysis of unheated broccoli varied among cultivars from 91 to 52% of hydrolysis products (Pinnacle > Marathon > Patriot > Brigadier). Boiling and microwave heating caused an initial loss of nitrile, with a concomitant increase in sulforaphane, followed by loss of sulforaphane, all within 1 min. In contrast, steaming enhanced sulforaphane yield between 1.0 and 3.0 min in all but Brigadier. These data are proof of concept that steaming for 1.0-3.0 min provides less nitrile and more sulforaphane yield from a broccoli meal.

Enhancing saccharification of cassava stems by starch hydrolysis prior to pretreatment

OpenAIRE

Martín, Carlos; Wei, Maogui; Xiong, Shaojun; Jönsson, Leif J.

2017-01-01

Chemical characterization of cassava stems from different origin revealed that glucans accounted for 54-63% of the dry weight, whereas 35-67% of these glucans consisted of starch. The cassava stems were subjected to a saccharification study including starch hydrolysis, pretreatment with either sulfuric acid or 1-ethyl-3-methylimidazolium acetate ([Emim]OAc), and enzymatic hydrolysis of cellulose. Starch hydrolysis prior to pretreatment decreased sugar degradation, improved enzymatic convertib...

Pepsin-Assisted Transglutaminase Modifi cation of Functional Properties of a Protein Isolate Obtained from Industrial Sunfl ower Meal

Directory of Open Access Journals (Sweden)

Petya Ivanova

2017-01-01

Full Text Available The utilization of industrial sunfl ower meal to produce protein-rich products for the food industry is an alternative approach for bett er and more effi cient use of this agricultural by-product. Sunfl ower meal proteins possess specifi c functional properties, which however need improvement to broaden their potential as supplements for delivering high-quality products for human nutrition. The aim of the study is to evaluate the combined infl uence of low-degree pepsin hydrolysis and transglutaminase (TG modifi cation on industrial sunfl ower meal protein isolate functionality at pH=2 to 10. Three TG-modifi ed pepsin hydrolysates with the degree of hydrolysis of 0.48, 0.71 and 1.72 % were produced and named TG-PH1, TG-PH2 and TG-PH3, respectively. All three TG-modifi ed pepsin hydrolysates exhibited improved solubility at pH between 3.5 and 5.5 as the highest was observed of TG-PH3 at protein isoelectric point (pI=4.5. Sunfl ower meal protein isolate and TG-modifi ed sunfl ower meal protein isolate had greater solubility than the three TG-modifi ed hydrolysates at pH7. Signifi cant improvement of foam making capacity (p<0.05 was achieved with all three TG-modifi ed pepsin hydrolysates in the entire pH area studied. Pepsin hydrolysis of the protein isolate with the three degrees of hydrolysis did not improve foam stability. Improved thermal stability was observed with TG-PH3 up to 80 °C compared to the protein isolate (pH=7. At 90 °C, TG modifi cation of the protein isolate alone resulted in the highest thermal stability. Pepsin hydrolysis followed by a treatment with TG could be used to produce sunfl ower protein isolates with improved solubility, foam making capacity and thermal stability for use in the food industry.

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch

International Nuclear Information System (INIS)

Say, R.; Şenay, R. Hilal; Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz; Akgöl, Sinan; Denizli, Adil

2013-01-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. K m values were 0.26 and 0.87 mM and V max values were 0.36 IU mg −1 and 22.32 IU mg −1 for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70–80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. - Highlights: ► Developing to prepare nanoprotein particles carrying α-amylase ► Characterization of nanostructured α-amylase ► Usability of α-amylase nanoparticles in hydrolysis of starch

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch

Energy Technology Data Exchange (ETDEWEB)

Say, R. [Anadolu University, Faculty of Science, Chemistry Department, Yunus Emre Campus, Eskişehir (Turkey); Şenay, R. Hilal [Ege University, Faculty of Science, Biochemistry Department, 35100 Bornova-Izmir (Turkey); Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz [Anadolu University, Faculty of Science, Chemistry Department, Yunus Emre Campus, Eskişehir (Turkey); Akgöl, Sinan, E-mail: sinanakgol@yahoo.co.uk [Ege University, Faculty of Science, Biochemistry Department, 35100 Bornova-Izmir (Turkey); Denizli, Adil [Hacettepe University, Faculty of Science, Chemistry Department, 06532 Ankara (Turkey)

2013-05-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. K{sub m} values were 0.26 and 0.87 mM and V{sub max} values were 0.36 IU mg{sup −1} and 22.32 IU mg{sup −1} for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70–80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. - Highlights: ► Developing to prepare nanoprotein particles carrying α-amylase ► Characterization of nanostructured α-amylase ► Usability of α-amylase nanoparticles in hydrolysis of starch.

Ion assisted deposition of thermally evaporated Ag and Al films

International Nuclear Information System (INIS)

Hwangbo, C.K.; Lingg, L.J.; Lehan, J.P.; Macleod, H.A.; Makous, J.L.; Kim, S.Y.; University of Arizona, Physics Department, Tucson, Arizona 85721; Aju University, Physics Department, Suwon, Korea)

1989-01-01

Optical, electrical, and microstructural effects of Ar ion bombardment and Ar incorporation on thermally evaporated Ag and Al thin films are investigated. The results show that as the momentum supplied to the growing films by the bombarding ions per arriving metal atom increases, the refractive index at 632.8 nm increases and the extinction coefficient decreases, lattice spacing expands, grain size decreases, electrical resistivity increases, and trapped Ar increases slightly. In Ag films, stress reverses from tensile to compressive and in Al films compressive stress increases. In the Al films the change in optical constants can be explained by the variation in void volume. The reversal of stress from tensile to compressive in Ag films requires a threshold level of momentum. The increase in electrical resistivity is related to the decrease in grain size and increase in trapped Ar in both types of film. Many of these properties correlate well with the momentum transferred, suggesting that the momentum is an important physical parameter in describing the influence of ion beam on growing thin films and determining the characteristics of thin metal films prepared by ion assisted deposition

Catalytic hydrolysis of ammonia borane via cobalt palladium nanoparticles.

Science.gov (United States)

Sun, Daohua; Mazumder, Vismadeb; Metin, Önder; Sun, Shouheng

2011-08-23

Monodisperse 8 nm CoPd nanoparticles (NPs) with controlled compositions were synthesized by the reduction of cobalt acetylacetonate and palladium bromide in the presence of oleylamine and trioctylphosphine. These NPs were active catalysts for hydrogen generation from the hydrolysis of ammonia borane (AB), and their activities were composition dependent. Among the 8 nm CoPd catalysts tested for the hydrolysis of AB, the Co(35)Pd(65) NPs exhibited the highest catalytic activity and durability. Their hydrolysis completion time and activation energy were 5.5 min and 27.5 kJ mol(-1), respectively, which were comparable to the best Pt-based catalyst reported. The catalytic performance of the CoPd/C could be further enhanced by a preannealing treatment at 300 °C under air for 15 h with the hydrolysis completion time reduced to 3.5 min. This high catalytic performance of Co(35)Pd(65) NP catalyst makes it an exciting alternative in pursuit of practical implementation of AB as a hydrogen storage material for fuel cell applications. © 2011 American Chemical Society

Gastric protein hydrolysis of raw and roasted almonds in the growing pig.

Science.gov (United States)

Bornhorst, Gail M; Drechsler, Krista C; Montoya, Carlos A; Rutherfurd, Shane M; Moughan, Paul J; Singh, R Paul

2016-11-15

Gastric protein hydrolysis may influence gastric emptying rate and subsequent protein digestibility in the small intestine. This study examined the gastric hydrolysis of dietary protein from raw and roasted almonds in the growing pig as a model for the adult human. The gastric hydrolysis of almond proteins was quantified by performing tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent image analysis. There was an interaction between digestion time, stomach region, and almond type for gastric protein hydrolysis (palmonds (compared to roasted almonds), hypothesized to be related to structural changes in almond proteins during roasting. Greater gastric protein hydrolysis was observed in the distal stomach (compared to the proximal stomach), likely related to the lower pH in the distal stomach. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of abalone β-glucuronidase substitution in current urine hydrolysis procedures.

Science.gov (United States)

Malik-Wolf, Brittany; Vorce, Shawn; Holler, Justin; Bosy, Thomas

2014-04-01

This study examined the potential of abalone β-glucuronidase as a viable and cost effective alternative to current hydrolysis procedures using acid, Helix pomatia β-glucuronidase and Escherichia coli β-glucuronidase. Abalone β-glucuronidase successfully hydrolyzed oxazepam-glucuronide and lorazepam-glucuronide within 5% of the spiked control concentration. Benzodiazepines present in authentic urine specimens were within 20% of the concentrations obtained with the current hydrolysis procedure using H. pomatia β-glucuronidase. JWH 018 N-(5-hydroxypentyl) β-d-glucuronide was hydrolyzed within 10% of the control concentration. Authentic urine specimens showed improved glucuronide cleavage using abalone β-glucuronidase with up to an 85% increase of drug concentration, compared with the results obtained using E. coli β-glucuronidase. The JWH 018 and JWH 073 carboxylic acid metabolites also showed increased drug concentrations of up to 24%. Abalone β-glucuronidase was able to completely hydrolyze a morphine-3-glucuronide control, but only 82% of total morphine was hydrolyzed in authentic urine specimens compared with acid hydrolysis results. Hydrolysis of codeine and hydromorphone varied between specimens, suggesting that abalone β-glucuronidase may not be as efficient in hydrolyzing the glucuronide linkages in opioid compounds compared with acid hydrolysis. Abalone β-glucuronidase demonstrates effectiveness as a low cost option for enzyme hydrolysis of benzodiazepines and synthetic cannabinoids.

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

Directory of Open Access Journals (Sweden)

Nguyen ThiQuynhHoa

2015-01-01

Full Text Available Abstract Hydrolysis of proteins involves the cleavage of peptide bonds to give peptides of varying sizes and amino acid composition. There are a number of types of hydrolysis enzymatic acid or alkali hydrolysis. Chemical hydrolysis is difficult to control and reduces the nutritional quality of products destroying L-form amino acids and producing toxic substances such as lysino-alanine. Enzymatic hydrolysis works without destructing amino acids and by avoiding the extreme temperatures and pH levels required for chemical hydrolysis the nutritional properties of the protein hydrolysates remain largely unaffected. In this research we investigate the fat removal and protein hydrolysis from pork meat to produce the enteral tube feeding nutritional protein hydrolysate for patient. Our results are as follows meat moisture 75.1 protein 22.6 lipid 1.71 ash 0.5 vitamin B1 1.384mg100g n hexantreatment at 80oCin 45 minutes and drying 30 minutes in 90oC.Viscosity of the hydrolysate is very low 2.240 0.092 cPand high degree of hydrolysis 31.390 0.138 . The final protein powder has balance nutritional components and acid amines low microorganisms which are safety for human consumption.

Composite piping: basic materials, manufacturing methods, hydrolysis resistance. Bibliographical data and state of the art

International Nuclear Information System (INIS)

Pays, M.F.

1997-01-01

EDF has decided to replace traditional materials by glass reinforced plastic for the manufacture of certain PWR water piping. However, these are liable to in-service degradation through the hydrolysis of the operating conditions which can involve mechanical stresses or specific temperature and humidity conditions. These resins have been the subject of bibliographical surveys and laboratory experiments providing the following main results: the water diffusion in the selected thermoset resins (polyester, vinyl-ester, epoxy) can reach one percent in weight, according to the relative humidity and temperature; the water absorption is a reversible phenomenon, at the beginning and is followed by hydrolysis, an irreversible deterioration affecting the chemical functions of the polymeric chain. Thermally activated, the reaction limits the temperature for the use of these resins; polyester resins are made of a large number of ester bonds and are highly sensitive to hydrolysis. These resins can be classified on the basis of the alcohol and acid which they come acid. A possible hydrolytic degradation does not prevent from using these resins in humid environments. The cooling towers in Belleville, Nogent ad Chooz are equipped with water collecting channels made of polyester laminates which have behaved satisfactorily since their installation in 1982. In acid environments, even concentrated, resins have a better behavior than in a neutral medium. However, they can be liable to stress corrosion. Polyester resins ar not suitable for use in concentrated base media. Vinyl-ester resins are more appropriate for this purpose, although their resistance will be lower than in a neutral environment. When resins are used as a matrix for composites, the presence of glass fibers modifies their behavior. The physico-chemical protection of the fiber/matrix interfaces and of the surface of the glass itself through the sizing of the fibers plays key role in the durability of the composites, which

Radiation degradation and the subsequent enzymatic hydrolysis of waste paper

International Nuclear Information System (INIS)

Kamakura, M.; Kaetsu, I.

1982-01-01

Various studies have been carried out to find methods for the pretreatment of waste cellulosic materials to make them more susceptible to enzymatic hydrolysis. In the work reported here, the effects of preirradiating waste papers on subsequent enzymatic hydrolysis have been studied

Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

Energy Technology Data Exchange (ETDEWEB)

Lu, Xingcai; Ji, Libin; Ma, Junjun; Zhou, Xiaoxin; Huang, Zhen [Key Lab. for Power Machinery and Engineering of MOE, Shanghai Jiao Tong University, 200240 Shanghai (China)

2011-02-15

This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively according to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)

Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

Directory of Open Access Journals (Sweden)

Akbarningrum Fatmawati

2013-06-01

Full Text Available The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC and pH (3, 4, 5. The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar. © 2013 BCREC UNDIP. All rights reservedReceived: 2nd October 2012; Revised: 31st January 2013; Accepted: 6th February 2013[How to Cite: Fatmawati, A., Agustriyanto, R., Liasari, Y. (2013. Enzymatic Hydrolysis of Alkaline Pre-treated Coconut Coir. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 34-39 (doi:10.9767/bcrec.8.1.4048.34-39[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4048.34-39] | View in  |

Simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero by on-line postcolumn derivation fluorescence detection and ultraviolet detection coupled two-dimensional high-performance liquid chromatography.

Science.gov (United States)

Cheng, Cheanyeh; Wu, Shing-Chen

2011-05-20

An innovative two-dimensional high-performance liquid chromatography system was developed for the simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero. A C8 reversed-phase chromatographic column with ultraviolet detection was used as the first dimension for the determination of aspartame, and a ligand-exchange chromatographic column with on-line postcolumn derivation fluorescence detection was employed as the second dimension for the analysis of amino acid enantiomers. The fluorimetric derivative reagent of amino acid enantiomers was o-phthaldialdehyde. The hydrolysis of aspartame in Coca-Cola Zero was induced by electric-heating or microwave heating. Aspartame was quantified by the matrix matched external standard calibration curve with a linear concentration range of 0-50 μg mL(-1) (r(2)=0.9984). The limit of detection (LOD) and the limit of quantification (LOQ) were 1.3 μg mL(-1) and 4.3 μg mL(-1), respectively. The amino acid enantiomers was analyzed by the matrix matched internal standard calibration method (D-leucine as the internal standard) with a linear concentration range of 0-10 μg mL(-1) (r(2)=0.9988-0.9997). The LODs and LOQs for L- and D-aspartic acid and L- and D-phenylalanine were 0.16-0.17 μg mL(-1) and 0.52-0.55 μg mL(-1), respectively, that was 12-13 times more sensitive than ultraviolet detection. The overall analysis accuracy for aspartame and amino acid enantiomers was 90.2-99.2% and 90.4-96.2%, respectively. The overall analysis precision for aspartame and amino acid enantiomers was 0.1-1.7% and 0.5-6.7%, respectively. Generally, the extent of aspartame hydrolysis increases with the increase of electro-thermal temperature, microwave power, and the duration of hydrolysis time. D-aspartic acid and D-phenylalanine can be observed with the electro-thermal racemization at the hydrolysis temperature 120°C for 1 day and only D-aspartic acid can be observed at the hydrolysis temperature 90°C for 2 and 3 days. For

Radiation degration and the subsequent enzymatic hydrolysis of waste papers

International Nuclear Information System (INIS)

Kamakura, M.; Kaetsu, I.

1982-01-01

In recent years, many methods have been proposed for the hydrolysis of waste cellulose to utilize it as a new source of alcohol. Because it is difficult to hydrolyze waste cellulosic materials effectivley with an enzyme, the effects of preirradiating waste papers on subsequent enzymatic hydrolysis was studied. Preirradiation (x rays from 60 Co) accelerated the hydrolysis rate of newspaper by cellulase and the reducing-sugar yield increased with increasing irradiation dose. It is thought that preirradiation probably contributes to loosening and releasing the compactly entangled structure of cellulose and lignin in the materials by radiation degradation

Bioethanol production: Pretreatment and enzymatic hydrolysis of softwood

Energy Technology Data Exchange (ETDEWEB)

Tengborg, Charlotte

2000-05-01

The enzymatic hydrolysis process can be used to produce bioethanol from softwood, which are the dominating raw material in the Northern hemisphere. This thesis deals with the development of the process focusing on the pretreatment and the enzymatic hydrolysis stages. The influence of pretreatment conditions on sugar yield, and the effect of inhibitors on the ethanol yield, were investigated for spruce and pine. The maximum yields of hemicellulose sugars and glucose were obtained under different pretreatment conditions. This indicates that two-stage pretreatment may be preferable. The added catalysts, H{sub 2}SO{sub 4} and SO{sub 2}, resulted in similar total sugar yields about 40 g/100 g dry raw material. However, the fermentability of SO{sub 2}-impregnated material was better. This pretreatment resulted in the formation of inhibitors to the subsequent process steps, e.g. sugar and lignin degradation products. The glucose yield in the enzymatic hydrolysis stage was affected by various parameters such as enzyme loading, temperature, pH, residence time, substrate concentration, and agitation. To decrease the amount of fresh water used and thereby waste water produced, the sugar-rich prehydrolysate from the pretreatment step was included in the enzymatic hydrolysis of the solid fraction, resulting in a reduction in the cellulose conversion of up to 36%. Different prehydrolysate detoxification methods, such as treatment with Ca(OH){sub 2}, laccase, and fermentation using yeast, were investigated. The latter was shown to be very efficient. The amount of fresh water used can be further reduced by recycling various process streams. This was simulated experimentally in a bench-scale process. A reduction in fresh water demand of 50% was obtained without any further negative effects on either hydrolysis or fermentation.

Modeling the mechanisms of biological GTP hydrolysis

DEFF Research Database (Denmark)

Carvalho, Alexandra T.P.; Szeler, Klaudia; Vavitsas, Konstantinos

2015-01-01

Enzymes that hydrolyze GTP are currently in the spotlight, due to their molecular switch mechanism that controls many cellular processes. One of the best-known classes of these enzymes are small GTPases such as members of the Ras superfamily, which catalyze the hydrolysis of the γ-phosphate bond...... in GTP. In addition, the availability of an increasing number of crystal structures of translational GTPases such as EF-Tu and EF-G have made it possible to probe the molecular details of GTP hydrolysis on the ribosome. However, despite a wealth of biochemical, structural and computational data, the way...

Water Availability as a Measure of Cellulose Hydrolysis Efficiency

DEFF Research Database (Denmark)

Hsieh, Chia-Wen

of sugars, salts, and surfactants impact the water relaxation time. Systems with high concentrations of sugars and salts tend to have low water availability, as these form strong interactions with water to keep their solubility, leaving less water available for hydrolysis. Thus, cellulase performance...... decreases. However, the addition of surfactants such as polyethylene glycol (PEG) increases the water mobility, leading to higher water availability, and ultimately higher glucose production. More specifically, the higher water availability boosts the activity of processive cellulases. Thus, water...... availability is vital for efficient hydrolysis, especially at high dry matter content where water availability is low. At high dry matter content, cellulase activity changes water interactions with biomass, affecting the water mobility. While swelling and fiber loosening also take place during hydrolysis...

Enzymatic hydrolysis of biomass at high-solids loadings – A review

International Nuclear Information System (INIS)

Modenbach, Alicia A.; Nokes, Sue E.

2013-01-01

Enzymatic hydrolysis is the unit operation in the lignocellulose conversion process that utilizes enzymes to depolymerize lignocellulosic biomass. The saccharide components released are the feedstock for fermentation. When performed at high-solids loadings (≥15% solids, w/w), enzymatic hydrolysis potentially offers many advantages over conversions performed at low- or moderate-solids loadings, including increased sugar and ethanol concentrations and decreased capital and operating costs. The goal of this review is to provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis. Included in this review is a brief discussion of the limitations, such as a lack of available water, difficulty with mixing and handling, insufficient mass and heat transfer, and increased concentration of inhibitors, associated with the use of high solids, as well as descriptions and findings of studies that performed enzymatic hydrolysis at high-solids loadings. Reactors designed and/or equipped for improved handling of high-solids slurries are also discussed. Lastly, this review includes a brief discussion of some of the operations that have successfully scaled-up and implemented high-solids enzymatic hydrolysis at pilot- and demonstration-scale facilities. -- Highlights: •High solids enzymatic hydrolysis needed for conversion process to be cost-effective. •Limitations must be addressed before benefits of high-solid loadings fully realized. •Some success with high-solids loadings at pilot and demonstration scale

Covalent Immobilization of β-Glucosidase on Magnetic Particles for Lignocellulose Hydrolysis

DEFF Research Database (Denmark)

Alftrén, Johan; Hobley, Timothy John

2013-01-01

β-Glucosidase hydrolyzes cellobiose to glucose and is an important enzyme in the consortium used for hydrolysis of cellulosic and lignocellulosic feedstocks. In the present work, β-glucosidase was covalently immobilized on non-porous magnetic particles to enable re-use of the enzyme. It was found...... that particles activated with cyanuric chloride and polyglutaraldehyde gave the highest bead-related immobilized enzyme activity when tested with p-nitrophenyl-β-D-glucopyranoside (104.7 and 82.2 U/g particles, respectively). Furthermore, the purified β-glucosidase preparation from Megazyme gave higher bead......-related enzyme activities compared to Novozym 188 (79.0 and 9.8 U/g particles, respectively). A significant improvement in thermal stability was observed for immobilized enzyme compared to free enzyme; after 5 h (at 65 °C), 36 % of activity remained for the former, while there was no activity in the latter...

Reaction rate of hydrolysis of iodine

International Nuclear Information System (INIS)

Miyake, Yoshikazu; Eguchi, Wataru; Adachi, Motonari

1979-01-01

Absorption rates of dilute iodine vapor contained in air by aqueous mixtures of sodium hydroxide and boric acid were measured using a laminar liquid jet column absorber at 298 K. Absorption rates in this system are controlled by a series of complex reactions taking place in the liquid phase. The reaction rate constant of iodine hydrolysis in the aqueous phase was determined from the absorption rates observed under the conditions that the base-catalytic hydrolysis reaction of iodine can be considered to be irreversible and that other reactions can be neglected. The absorption rates calculated theoretically with the rate constant value obtained above were in good accordance with the whole experimental data observed for a wide range of experimental conditions. (author)

Study on the Hydrolysis Kinetics of Xylan on Different Acid Catalysts

Energy Technology Data Exchange (ETDEWEB)

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

2014-04-15

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

Evaluation of physical structural features on influencing enzymatic hydrolysis efficiency of micronized wood

Science.gov (United States)

Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

2016-01-01

Enzymatic hydrolysis of lignocellulosic biomass is highly dependent on the changes in structural features after pretreatment. Mechanical milling pretreatment is an effective approach to alter the physical structure of biomass and thus improve enzymatic hydrolysis. This study examined the influence of structural characteristics on the enzymatic hydrolysis of micronized...

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions

DEFF Research Database (Denmark)

Jensen, T. R.; Lastra Milone, T.; Petersen, G.

2017-01-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h...... for calculating hydrolysis rates based on soluble COD were compared. Two-way ANOVA with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically...... significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process (ARP) can...

Small fan assisted air conditioner for thermal comfort and energy saving in Thailand

International Nuclear Information System (INIS)

Atthajariyakul, Surat; Lertsatittanakorn, Charoenporn

2008-01-01

From the fact that Thai people have a tolerance to high air temperature and are accustomed to high air movement from electric fans in non-air conditioned space, this paper proposes the use of small fan assisted air conditioners for human thermal comfort and energy saving in Thailand. In the study, a total 15 students were tested in a 2.5 x 3.5 x 2.5 m 3 test room equipped with a 12,000 Btu/h split type air conditioner. During the tests, the room air temperature was varied from 25, 26, 27 and 28 deg. C every 1 h. A small fan with 15 cm diameter was placed in front of each subject. In each hour, the small fan was varied to supply a small area with velocity from 0.2, 0.5, 1, 1.5 and 2 m/s. In each condition, the subjects were asked to vote for their thermal sensation. The results showed that the temperature set point could be increased up to 28 deg. C when a small fan was used to supply local air velocity from 0.5 to 2 m/s according to individual preference. This would reduce the electricity consumption of the air conditioning unit. According to the proposed method, this can save energy for office buildings in the commercial sector as high as 1959.51 GWh/year

Hydrolysis of biomass material

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Andrew J.; Orth, Rick J.; Franz, James A.; Alnajjar, Mikhail

2004-02-17

A method for selective hydrolysis of the hemicellulose component of a biomass material. The selective hydrolysis produces water-soluble small molecules, particularly monosaccharides. One embodiment includes solubilizing at least a portion of the hemicellulose and subsequently hydrolyzing the solubilized hemicellulose to produce at least one monosaccharide. A second embodiment includes solubilizing at least a portion of the hemicellulose and subsequently enzymatically hydrolyzing the solubilized hemicellulose to produce at least one monosaccharide. A third embodiment includes solubilizing at least a portion of the hemicellulose by heating the biomass material to greater than 110.degree. C. resulting in an aqueous portion that includes the solubilized hemicellulose and a water insoluble solids portion and subsequently separating the aqueous portion from the water insoluble solids portion. A fourth embodiment is a method for making a composition that includes cellulose, at least one protein and less than about 30 weight % hemicellulose, the method including solubilizing at least a portion of hemicellulose present in a biomass material that also includes cellulose and at least one protein and subsequently separating the solubilized hemicellulose from the cellulose and at least one protein.

Interaction between amylose and 1-butanol during 1-butanol-hydrochloric acid hydrolysis of normal rice starch.

Science.gov (United States)

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. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Effects of acid hydrolysis intensity on the properties of starch/xanthan mixtures.

Science.gov (United States)

Jiang, Min; Hong, Yan; Gu, Zhengbiao; Cheng, Li; Li, Zhaofeng; Li, Caiming

2018-01-01

The effects of acid hydrolysis intensity on the physicochemical properties of starch/xanthan gum (XG) system were studied. Waxy corn starch (WCS) was subjected to different concentrations of hydrochloric acid, and crystallization and relative molecular weight analysis were performed. The results revealed that the starch granules became smaller during acid hydrolysis. X-ray diffraction pattern analysis showed that the crystal structure did not change with acid hydrolysis. Evaluation of the properties and digestibility of different acid-thinned starch/XG systems indicated that the viscosity of acid-thinned starch/XG decreased with increased acid hydrolysis intensity. Rheological property measurements indicated that the compound systems were a pseudo-plastic fluid, which is a typical weak gel structure. Finally, we show that the WCS1.0M/XG has the highest stability of the tested mixtures. We conclude that adjusting the conditions of acid hydrolysis improves the stability and food quality-enhancing properties of starch. Copyright © 2017 Elsevier B.V. All rights reserved.

Secondary deuterium isotope effects in the hydrolysis of some acetals

International Nuclear Information System (INIS)

Paterson, R.V.

Secondary α-deuterium kinetic isotope effects have been determined in the hydrolyses of some acetals. Benzaldehyde dimethyl acetal and 2-phenyl-1,3-dioxolan show isotope effects in agreement with an A1 mechanism. 2-Phenyl-4,4,5,5-tetramethyl-1,3-dioxolan, which has been shown to undergo hydrolysis by an A2 type mechanism, has an isotope effect in agreement with participation by water in the transition state. Hydrolysis of benzylidene norbornanediols, although complicated by isomerisation, has an isotope effect in agreement with an A2 mechanism. Kinetic isotope effects in acetals which have a neighbouring carboxyl group have also been determined. Hydrolysis of 2-carboxybenzaldehyde dimethyl acetal in aqueous and 82% w/w dioxan-water buffers has isotope effects in agreement with a large degree of carbonium ion character in the transition state. Anderson and Capon proposed nucleophilic participation in the hydrolysis of this acetal in 82% dioxan-water. The isotope effect determined in this study is not in agreement with this finding. Hydrolysis of 2-(2'-carboxyphenyl)-4,4,5,5-tetramethyl-1,3-dioxolan shows an isotope effect larger than the corresponding dioxolan without the carboxyl group in agreement with some carbonium ion character in the transition state. A new synthesis of a deuterated aldehyde is described which might be general for aldehydes which will not form benzoins readily. (author)

Recycle of enzymes and substrate following enzymatic hydrolysis of steam-pretreated aspenwood

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

1987-09-01

The commercial production of chemicals and fuels from lignocellulosic residues by enzymatic means still requires considerable research on both the technical and economic aspects. Two technical problems that have been identified as requiring further research are the recycle of the enzymes used in hydrolysis and the reuse of the recalcitrant cellulose remaining after incomplete hydrolysis. Enzyme recycle is required to lower the cost of the enzymes, while the reuse of the spent cellulose will lower the feedstock cost. The conversion process studied was a combined enzymatic hydrolysis and fermentation (CHF) procedure that utilized the cellulolytic enzymes derived from the fungus Trichoderma harzianum E58 and the yeast Saccharomyces cerevisiae. The rate and extent of hydrolysis and ethanol production was monitored as was the activity and hydrolytic potential of the enzymes remaining in the filtrate after the hydrolysis period. When a commercial cellulose was used as the substrate for a routine 2-day CHF process, 60% of the original filter paper activity could be recovered. When steam-treated, water-extracted aspenwood was used as the substrate, only 13% of the original filter paper activity was detected after a similar procedure. The combination of 60% spent enzymes with 40% fresh enzymes resulted in the production of 30% less reducing sugars than the original enzyme mixture. Since 100% hydrolysis of the cellulose portion is seldom accomplished in an enzymatic hydrolysis process, the residual cellulose was used as a substrate for the growth of T. harzianum E58 and production of cellulolytic enzymes. The residue remaining after the CHF process was used as a substrate for the production of the cellulolytic enzymes. The production of enzymes from the residue of the Solka Floc hydrolysis was greater than the production of enzymes from the original Solka Floc. (Refs. 14).

Dynamic Modeling of Indole Glucosinolate Hydrolysis and Its Impact on Auxin Signaling

Directory of Open Access Journals (Sweden)

Daniel Vik

2018-04-01

Full Text Available Plants release chemicals to deter attackers. Arabidopsis thaliana relies on multiple defense compounds, including indol-3-ylmethyl glucosinolate (I3G, which upon hydrolysis initiated by myrosinase enzymes releases a multitude of bioactive compounds, among others, indole-3-acetonitrile and indole-3-acetoisothiocyanate. The highly unstable isothiocyanate rapidly reacts with other molecules. One of the products, indole-3-carbinol, was reported to inhibit auxin signaling through binding to the TIR1 auxin receptor. On the contrary, the nitrile product of I3G hydrolysis can be converted by nitrilase enzymes to form the primary auxin molecule, indole-3-acetic acid, which activates TIR1. This suggests that auxin signaling is subject to both antagonistic and protagonistic effects of I3G hydrolysis upon attack. We hypothesize that I3G hydrolysis and auxin signaling form an incoherent feedforward loop and we build a mathematical model to examine the regulatory network dynamics. We use molecular docking to investigate the possible antagonistic properties of different I3G hydrolysis products by competitive binding to the TIR1 receptor. Our simulations reveal an uncoupling of auxin concentration and signaling, and we determine that enzyme activity and antagonist binding affinity are key parameters for this uncoupling. The molecular docking predicts that several I3G hydrolysis products strongly antagonize auxin signaling. By comparing a tissue disrupting attack – e.g., by chewing insects or necrotrophic pathogens that causes rapid release of I3G hydrolysis products – to sustained cell-autonomous I3G hydrolysis, e.g., upon infection by biotrophic pathogens, we find that each scenario gives rise to distinct auxin signaling dynamics. This suggests that plants have different defense versus growth strategies depending on the nature of the attack.

Combined wet oxidation and alkaline hydrolysis of polyvinylchloride

DEFF Research Database (Denmark)

Sørensen, E.; Bjerre, A.B.

1992-01-01

In view of the widespread aversion to burning polyvinylchloride (PVC) together with municipal waste, we have attempted an alternative approach to its decomposition. This paper describes a combined wet oxidation/alkaline hydrolysis yielding water soluble, biodegradable products. Experiments were...... carried out at temperatures from 180-260 degree C and reaction times of 8-24 min. The chloride liberated provides information on the rate constants. Considering the measured Cl- and Chemical Oxygen Demand (COD) values, we find hydrolysis and oxidation processes to be interdependent. The main products...

Optimization of enzymatic hydrolysis of guar gum using response surface methodology.

Science.gov (United States)

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2014-08-01

Guar gum is a polysaccharide obtained from guar seed endosperm portion. Enzymatically hydrolyzed guar gum is low in viscosity and has several health benefits as dietary fiber. In this study, response surface methodology was used to determine the optimum conditions for hydrolysis that give minimum viscosity of guar gum. Central composite was employed to investigate the effects of pH (3-7), temperature (20-60 °C), reaction time (1-5 h) and cellulase concentration (0.25-1.25 mg/g) on viscosity during enzymatic hydrolysis of guar (Cyamopsis tetragonolobus) gum. A second order polynomial model was developed for viscosity using regression analysis. Results revealed statistical significance of model as evidenced from high value of coefficient of determination (R(2) = 0.9472) and P < 0.05. Viscosity was primarily affected by cellulase concentration, pH and hydrolysis time. Maximum viscosity reduction was obtained when pH, temperature, hydrolysis time and cellulase concentration were 6, 50 °C, 4 h and 1.00 mg/g, respectively. The study is important in optimizing the enzymatic process for hydrolysis of guar gum as potential source of soluble dietary fiber for human health benefits.

Antioxidative activities of hydrolysates from edible birds nest using enzymatic hydrolysis

Science.gov (United States)

Muhammad, Nurul Nadia; Babji, Abdul Salam; Ayub, Mohd Khan

2015-09-01

Edible bird's nest protein hydrolysates (EBN) were prepared via enzymatic hydrolysis to investigate its antioxidant activity. Two types of enzyme (alcalase and papain) were used in this study and EBN had been hydrolysed with different hydrolysis time (30, 60, 90 and 120 min). Antioxidant activities in EBN protein hydrolysate were measured using DPPH, ABTS+ and Reducing Power Assay. From this study, increased hydrolysis time from 30 min to 120 min contributed to higher DH, as shown by alcalase (40.59%) and papain (24.94%). For antioxidant assay, EBN hydrolysed with papain showed higher scavenging activity and reducing power ability compared to alcalase. The highest antioxidant activity for papain was at 120 min hydrolysis time with ABTS (54.245%), DPPH (49.78%) and Reducing Power (0.0680). Meanwhile for alcalase, the highest antioxidant activity was at 30 min hydrolysis time. Even though scavenging activity for EBN protein hydrolysates were high, the reducing power ability was quite low as compared to BHT and ascorbic Acid. This study showed that EBN protein hydrolysate with alcalase and papain treatments potentially exhibit high antioxidant activity which have not been reported before.

The kinetics of hydrolysis of acetylsalicylic acid (Aspirin) in different ...

African Journals Online (AJOL)

The kinetics of hydrolysis of Acetylsalicylic acid (Aspirin) to salicylic acid was followed by the direct spectrophotometric measurement of the amount of salicylic acid produced with time. Salicylic acid was complexed with ferric ion giving a characteristic purple colour (λlm 523nm). The kinetics of hydrolysis was found to follow ...

Influence of cooling rate in planar thermally assisted magnetic random access memory: Improved writeability due to spin-transfer-torque influence

International Nuclear Information System (INIS)

Chavent, A.; Ducruet, C.; Portemont, C.; Creuzet, C.; Alvarez-Hérault, J.; Vila, L.; Sousa, R. C.; Prejbeanu, I. L.; Dieny, B.

2015-01-01

This paper investigates the effect of a controlled cooling rate on magnetic field reversal assisted by spin transfer torque (STT) in thermally assisted magnetic random access memory. By using a gradual linear decrease of the voltage at the end of the write pulse, the STT decays more slowly or at least at the same rate as the temperature. This condition is necessary to make sure that the storage layer magnetization remains in the desired written direction during cooling of the cell. The influence of the write current pulse decay rate was investigated on two exchange biased synthetic ferrimagnet (SyF) electrodes. For a NiFe based electrode, a significant improvement in writing reproducibility was observed using a gradual linear voltage transition. The write error rate decreases by a factor of 10 when increasing the write pulse fall-time from ∼3 ns to 70 ns. For comparison, a second CoFe/NiFe based electrode was also reversed by magnetic field assisted by STT. In this case, no difference between sharp and linear write pulse fall shape was observed. We attribute this observation to the higher thermal stability of the CoFe/NiFe electrode during cooling. In real-time measurements of the magnetization reversal, it was found that Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling in the SyF electrode vanishes for the highest pulse voltages that were used due to the high temperature reached during write. As a result, during the cooling phase, the final state is reached through a spin-flop transition of the SyF storage layer

Deciphering Intrinsic Inter-subunit Couplings that Lead to Sequential Hydrolysis of F 1 -ATPase Ring

Science.gov (United States)

Dai, Liqiang; Flechsig, Holger; Yu, Jin

2017-10-01

The rotary sequential hydrolysis of metabolic machine F1-ATPase is a prominent feature to reveal high coordination among multiple chemical sites on the stator F1 ring, which also contributes to tight coupling between the chemical reaction and central {\\gamma}-shaft rotation. High-speed AFM experiments discovered that the sequential hydrolysis was maintained on the F1 ring even in the absence of the {\\gamma} rotor. To explore how the intrinsic sequential performance arises, we computationally investigated essential inter-subunit couplings on the hexameric ring of mitochondrial and bacterial F1. We first reproduced the sequential hydrolysis schemes as experimentally detected, by simulating tri-site ATP hydrolysis cycles on the F1 ring upon kinetically imposing inter-subunit couplings to substantially promote the hydrolysis products release. We found that it is key for certain ATP binding and hydrolysis events to facilitate the neighbor-site ADP and Pi release to support the sequential hydrolysis. The kinetically feasible couplings were then scrutinized through atomistic molecular dynamics simulations as well as coarse-grained simulations, in which we enforced targeted conformational changes for the ATP binding or hydrolysis. Notably, we detected the asymmetrical neighbor-site opening that would facilitate the ADP release upon the enforced ATP binding, and computationally captured the complete Pi release through charge hopping upon the enforced neighbor-site ATP hydrolysis. The ATP-hydrolysis triggered Pi release revealed in current TMD simulation confirms a recent prediction made from statistical analyses of single molecule experimental data in regard to the role ATP hydrolysis plays. Our studies, therefore, elucidate both the concerted chemical kinetics and underlying structural dynamics of the inter-subunit couplings that lead to the rotary sequential hydrolysis of the F1 ring.

A predictive thermal dynamic model for parameter generation in the laser assisted direct write process

International Nuclear Information System (INIS)

Shang Shuo; Fearon, Eamonn; Wellburn, Dan; Sato, Taku; Edwardson, Stuart; Dearden, G; Watkins, K G

2011-01-01

The laser assisted direct write (LADW) method can be used to generate electrical circuitry on a substrate by depositing metallic ink and curing the ink thermally by a laser. Laser curing has emerged over recent years as a novel yet efficient alternative to oven curing. This method can be used in situ, over complicated 3D contours of large parts (e.g. aircraft wings) and selectively cure over heat sensitive substrates, with little or no thermal damage. In previous studies, empirical methods have been used to generate processing windows for this technique, relating to the several interdependent processing parameters on which the curing quality and efficiency strongly depend. Incorrect parameters can result in a track that is cured in some areas and uncured in others, or in damaged substrates. This paper addresses the strong need for a quantitative model which can systematically output the processing conditions for a given combination of ink, substrate and laser source; transforming the LADW technique from a purely empirical approach, to a simple, repeatable, mathematically sound, efficient and predictable process. The method comprises a novel and generic finite element model (FEM) that for the first time predicts the evolution of the thermal profile of the ink track during laser curing and thus generates a parametric map which indicates the most suitable combination of parameters for process optimization. Experimental data are compared with simulation results to verify the accuracy of the model.

Continuous enzymatic hydrolysis of lignocellulosic biomass with simultaneous detoxification and enzyme recovery.

Science.gov (United States)

Gurram, Raghu N; Menkhaus, Todd J

2014-07-01

Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

Hydrolysis of whey lactose by immobilized β-Galactosidase

Directory of Open Access Journals (Sweden)

Marcela Panaro Mariotti

2008-12-01

Full Text Available Hydrolysis of whey lactose to glucose and galactose by immobilized galactosidase comes as an alternative to enlarge the possibilities of commercial use of this feedstock. To be applied at industrial scale, the process should be performed continuously .This work aimed to study the hydrolysis of whey lactose by an immobilized enzyme reactor. b-Galactosidase from Aspergillus oryzae was immobilized on silica and activity and stability were evaluated. The best immobilization results were attained by using glutaraldehyde as support's activator and enzyme stabilizer. The optimized enzyme proportion for immobilization was 15-20 mg g-1 of support. Treatments of whey were performed (microfiltration, thermal treatment and ultrafiltration, seeking the elimination of sludge, and the effects on operating the fixed bed reactor were evaluated. Ultrafiltration was the best treatment towards a proper substrate solution for feeding the reactor.A hidrólise de lactose de soro de leite, resultando em glicose e galactose, apresenta-se como uma alternativa para ampliar as possibilidades de uso comercial deste insumo. Para ser aplicado em escala industrial, o processo deve ser operado de modo contínuo. Reporta-se o estudo de um sistema objetivando hidrólise de lactose de soro de leite através de um reator com enzima imobilizada. b-Galactosidase de Aspergillus oryzae foi imobilizada em sílica, sendo avaliadas a estabilidade e atividade. Os melhores resultados de imobilização foram obtidos usando glutaraldeído como ativante do suporte e estabilizador da enzima. A proporção otimizada entre enzima e suporte foi 15-20 mg.g-1. Foram estudadas formas de tratamento do soro (microfiltração, tratamento térmico e ultrafiltração, objetivando eliminação de material suspenso, e avaliando os efeitos na operação de reator de leito fixo. A ultrafiltração foi o melhor tratamento, na busca de uma solução de substrato apropriada para o reator contínuo.

Model assisted startup of anaerobic digesters fed with thermally hydrolysed activated sludge.

Science.gov (United States)

Batstone, D J; Balthes, C; Barr, K

2010-01-01

This paper presents the use of the IWA ADM1 to predict and interpret results from two full-scale anaerobic digesters fed with thermal hyrolysate (waste activated sludge with a long upstream sludge age) from a Cambi hydrolysis process operating at 165°C and 6 bar-g. The first digester was fed conventionally-though intermittently, while the second was heavily diluted through a substantial component of the evaluation period (110 days). There were a number of important outcomes-related to both model application, and model predictions. Input and inert COD: mass ratio was very important, and was considerably higher than the 1.42 g g⁻¹ used for biomass throughout the IWA activated sludge and anaerobic digestion models. Input COD: VS ratio was 1.6 g g⁻¹, and inert COD: VS ratio was 1.7 g g⁻¹. The model succeeded on a number of levels, including effective prediction of important outputs (degradability, gas flow and composition, and final solids), clarification of the substantial data scatter, prediction of recovery times during operationally poor periods, and cross-validation of the results between digester 1 and digester 2. Key failures in model performance were related to an early incorrect assumption of the COD: VS ratio of 1.42 g g⁻¹, and intermittent high acetate levels, most likely caused by inhibition, and rapid acclimatisation to ammonia. The acute free ammonia limit was found to be 0.008 M NH(3)-N, while the chronic inhibition constant (K(I,NH₃,ac)) was 0.007 ± 0.001 M NH₃-N. Overall, this is a complex system, and application of the model added significant confidence to the initial operational decisions during an aggressive startup on an atypical feed.

Kinetic study of hydrolysis of coconut fiber into glucose

Science.gov (United States)

Muhaimin, Sudiono, Sri

2017-03-01

Kinetic study of hydrolysis of coconut fiber into glucose has been done. The aim of this research was to study of the effect of time and temperature to the glucose as the result of the conversion of coconut fiber. The various temperature of the hydrolysis process were 30 °C, 48 °C, 72 °C and 95 °C and the various time of the hydrolysis process were 0, 15, 30, 60, 120, 180, 240, 300 minutes. A quantitative analysis was done by measured the concentration of the glucose as the result of the conversion of coconut fiber. The result showed that the rate constant from the various temperature were 3.10-4 minute-1; 8.10-4 minutees-1; 84.10-4 minute-1, and 205.10-4 minute-1, and the energy activation was 7,69. 103 kJ/mol.

Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain

Directory of Open Access Journals (Sweden)

Kathrine Holmgaard Bak

2018-02-01

Full Text Available There is a growing market for the use of hydrolysates from animal side-streams for production of high-protein supplements. However, there can be issues with development of off-flavors, either due to the raw material in question or due to the hydrolysis process itself. This study examined the development of volatile compounds during hydrolysis of hemoglobin. Briefly, porcine hemoglobin was hydrolyzed by 0.5% papain for up to 5 h, and the development of volatile compounds was analyzed via gas chromatography-mass spectrometry. The results showed that there was significant development of a number of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found in a control without enzyme.

Optimization of Enzymatic Hydrolysis of Waste Bread before Fermentation

OpenAIRE

Hudečková, Helena; Šupinová, Petra; Ing. Mgr. Libor Babák, Ph.D., MBA

2017-01-01

Finding of optimal hydrolysis conditions is important for increasing the yield of saccharides. The higher yield of saccharides is usable for increase of the following fermentation effectivity. In this study optimal conditions (pH and temperature) for amylolytic enzymes were searched. As raw material was used waste bread. Two analytical methods for analysis were used. Efficiency and process of hydrolysis was analysed spectrophotometrically by Somogyi-Nelson method. Final yields of glucose were...

Hydrolysis of ferric chloride in solution

International Nuclear Information System (INIS)

Lussiez, G.; Beckstead, L.

1996-11-01

The Detox trademark process uses concentrated ferric chloride and small amounts of catalysts to oxidize organic compounds. It is under consideration for oxidizing transuranic organic wastes. Although the solution is reused extensively, at some point it will reach the acceptable limit of radioactivity or maximum solubility of the radioisotopes. This solution could be cemented, but the volume would be increased substantially because of the poor compatibility of chlorides and cement. A process has been developed that recovers the chloride ions as HCl and either minimizes the volume of radioactive waste or permits recycling of the radioactive chlorides. The process involves a two-step hydrolysis at atmospheric pressure, or preferably under a slight vacuum, and relatively low temperature, about 200 degrees C. During the first step of the process, hydrolysis occurs according to the reaction below: FeCl 3 liquid + H 2 O → FeOCl solid + 2 HCl gas During the second step, the hot, solid, iron oxychloride is sprayed with water or placed in contact with steam, and hydrolysis proceeds to the iron oxide according to the following reaction: 2 FeOCl solid + H 2 O → Fe 2 O 3 solid + 2 HCl gas . The iron oxide, which contains radioisotopes, can then be disposed of by cementation or encapsulation. Alternately, these chlorides can be washed off of the solids and can then either be recycled or disposed of in some other way

Effect of Acid mixtures on the Hydrolysis of Coconut Coir for ...

African Journals Online (AJOL)

MICHAEL HORSFALL

and the independent variables (time, temperature, nitric acid concentration and acetic acid ... nitric and acetic acid as well as the hydrolysis time and temperature all positively influenced ..... Corn Starch Using Aspergillus niger. ... digestion and acid hydrolysis of nitrocellulose, ... Optimization of a-amylase production by.

Lactose Hydrolysis in Milk and Dairy Whey Using Microbial β-Galactosidases

Directory of Open Access Journals (Sweden)

Michele Dutra Rosolen

2015-01-01

Full Text Available This work aimed at evaluating the influence of enzyme concentration, temperature, and reaction time in the lactose hydrolysis process in milk, cheese whey, and whey permeate, using two commercial β-galactosidases of microbial origins. We used Aspergillus oryzae (at temperatures of 10 and 55°C and Kluyveromyces lactis (at temperatures of 10 and 37°C β-galactosidases, both in 3, 6, and 9 U/mL concentrations. In the temperature of 10°C, the K. lactis β-galactosidase enzyme is more efficient in the milk, cheese whey, and whey permeate lactose hydrolysis when compared to A. oryzae. However, in the enzyme reaction time and concentration conditions evaluated, 100% lactose hydrolysis was not reached using the K. lactis β-galactosidase. The total lactose hydrolysis in whey and permeate was obtained with the A. oryzae enzyme, when using its optimum temperature (55°C, at the end of a 12 h reaction, regardless of the enzyme concentration used. For the lactose present in milk, this result occurred in the concentrations of 6 and 9 U/mL, with the same time and temperature conditions. The studied parameters in the lactose enzymatic hydrolysis are critical for enabling the application of β-galactosidases in the food industry.

Xylan hydrolysis in Populus trichocarpa × P. deltoides and model substrates during hydrothermal pretreatment.

Science.gov (United States)

Trajano, Heather L; Pattathil, Sivakumar; Tomkins, Bruce A; Tschaplinski, Timothy J; Hahn, Michael G; Van Berkel, Gary J; Wyman, Charles E

2015-03-01

Previous studies defined easy and difficult to hydrolyze fractions of hemicellulose that may result from bonds among cellulose, hemicellulose, and lignin. To understand how such bonds affect hydrolysis, Populus trichocarpa × Populus deltoides, holocellulose isolated from P. trichocarpa × P. deltoides and birchwood xylan were subjected to hydrothermal flow-through pretreatment. Samples were characterized by glycome profiling, HPLC, and UPLC-MS. Glycome profiling revealed steady fragmentation and removal of glycans from solids during hydrolysis. The extent of polysaccharide fragmentation, hydrolysis rate, and total xylose yield were lowest for P. trichocarpa × P. deltoides and greatest for birchwood xylan. Comparison of results from P. trichocarpa × P. deltoides and holocellulose suggested that lignin-carbohydrate complexes reduce hydrolysis rates and limit release of large xylooligomers. Smaller differences between results with holocellulose and birchwood xylan suggest xylan-cellulose hydrogen bonds limited hydrolysis, but to a lesser extent. These findings imply cell wall structure strongly influences hydrolysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ultrasonic-assisted preparation of graphene oxide carboxylic acid polyvinyl alcohol polymer film and studies of thermal stability and surface resistivity.

Science.gov (United States)

Li, Yongshen; Li, Jihui; Li, Yuehai; Li, Yali; Song, Yunan; Niu, Shuai; Li, Ning

2018-01-01

In this paper, flake graphite, nitric acid and acetic anhydride are used to prepare graphene oxide carboxylic acid (GO-COOH) via an ultrasonic-assisted method, and GO-COOH and polyvinyl alcohol polymer (PVA) are used to synthesize graphene oxide carboxylic acid polyvinyl alcohol polymer (GO-COOPVA) via the ultrasonic-assisted method, and GO-COOPVA is used to manufacture graphene oxide carboxylic acid polyvinyl alcohol polymer film (GO-COOPVA film) via a solidification method, and the structure and morphology of GO-COOH, GO-COOPVA and GO-COOPVA film are characterized, and the thermal stability and surface resistivity are measured in the case of the different amount of GO-COOH. Based on the characterization and measurement, it has been successively confirmed and attested that carboxyl groups implant on 2D lattice of GO to form GO-COOH, and GO-COOH and PVA have the esterification reaction to produce GO-COOPVA, and GO-COOPVA consists of 2D lattice of GO-COOH and the chain of PVA connected in the form of carboxylic ester, and GO-COOPVA film is composed of GO-COOPVA, and the thermal stability of GO-COOPVA film obviously improves in comparison with PVA film, and the surface resistivity of GO-COOPVA film clearly decreases. Copyright © 2017 Elsevier B.V. All rights reserved.

Lactose hydrolysis and milk powder production: technological aspects

Directory of Open Access Journals (Sweden)

Jansen Kelis Ferreira Torres

2017-06-01

Full Text Available The food industry has the challenge and the opportunity to develop new products with reduced or low lactose content in order to meet the needs of a growing mass of people with lactose intolerance. The manufacture of spray dried products with hydrolyzed lactose is extremely challenging. These products are highly hygroscopic, which influence the productivity and conservation of the powders, not to mention the undesirable and inevitable technological problem of constant clogging of drying chambers. The aim of this study was to evaluate the effect of different levels (0%, 25%, 50%, 75% and > 99% of enzymatic lactose hydrolysis on the production and storage of whole milk powder. The samples were processed in a pilot plant and characterized in relation to their composition analysis; to their degree of hydrolysis of lactose; and to their sorption isotherms. The results indicated the hydrolysis of lactose may affect the milk powder production due to a higher extent of powder adhesion within the spray dryer chambers and due to a higher tendency to absorb water during storage.

Hemicellulose hydrolysis catalysed by solid acids

NARCIS (Netherlands)

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

2013-01-01

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

Cellulose nanowhiskers from coconut husk fibers: effect of preparation conditions on their thermal and morphological behavior

Science.gov (United States)

Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis from coconut husk fibers which had previously been submitted to a delignification process. The effects of preparation conditions on the thermal and morphological behavior of the nanocrystals were investigated. Cellulose nanowhisker sus...

Hydrolysis of polyacrylamide containing associative hydrophobic groups: effect of the degree of hydrolysis and ionic strength on the viscosity in aqueous medium

International Nuclear Information System (INIS)

Lima, Bruna V. de; Vidal, Rosangela R.L.; Reis, Jeanne H.C. dos; Balaban, Rosangela de C.

2009-01-01

The HAPAM-10N polymer (hydrophobically modified and partially hydrolyzed polyacrylamide) was obtained by partial hydrolysis of HAPAM (hydrophobically modified polyacrylamide) precursor containing very low amount of hydrophobic groups (0.75%) in 0.1 M NaCl and 0.25 M NaOH aqueous solutions, at 40 deg C for 10 min. Hydrolysis degree of 44.64 % was obtained by 13 C NMR. The viscosity of polymers solutions was evaluated as a function of polymer concentration, ionic strength and temperature, at constant shear rate. The viscosity of HAPAM solutions increased with polymer concentration, however, it did not change significantly with the increase of ionic strength, and decreased with the temperature enhancement. The viscosity of HAPAM-10N solutions increased significantly in distilled water, due to electrostatic repulsions among carboxylate groups. However, with the increase of polymer concentration, ionic strength and temperature, it was not observed a significant increase of viscosity, probably due to the low amount of hydrophobic groups and high hydrolysis degree. (author)

Thermal loading study for FY 1995

International Nuclear Information System (INIS)

1996-01-01

This report provides the results of sensitivity analyses designed to assist the test planners in focusing their in-situ measurements on parameters that appear to be important to waste isolation. Additionally, the study provides a preliminary assessment of the feasibility of certain thermal management options. A decision on thermal loading is a critical part of the scientific and engineering basis for evaluating regulatory compliance of the potential repository for waste isolation. To show, with reasonable assurance, that the natural and engineered barriers will perform adequately under expected repository conditions (thermally perturbed) will require an integrated approach based on thermal testing (laboratory, and in-situ), natural analog observations, and analytic modeling. The Office of Civilian Radioactive Waste Management needed input to assist in the planning of the thermal testing program. Additionally, designers required information on the viability of various thermal management concepts. An approximately 18-month Thermal Loading Study was conducted from March, 1994 until September 30, 1995 to address these issues. This report documents the findings of that study. 89 refs., 71 figs., 33 tabs

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

Science.gov (United States)

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. Copyright © 2013 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2017-02-01

In the present study, microcrystalline cellulose (MCC) was isolated from oil palm fronds (OPF) using chemo-mechanical process. Wherein, alkaline hydrogen peroxide (AHP) was utilized to extract OPF fibre at different AHP concentrations. The OPF pulp fibre was then bleached with acidified sodium chlorite solution followed by the acid hydrolysis using hydrochloric acid. Several analytical methods were conducted to determine the influence of AHP concentration on thermal properties, morphological properties, microscopic and crystalline behaviour of isolated MCC. Results showed that the MCC extracted from OPF fibres had fibre diameters of 7.55-9.11nm. X-ray diffraction (XRD) analyses revealed that the obtained microcrystalline fibre had both celluloses I and cellulose II polymorphs structure, depending on the AHP concentrations. The Fourier transmission infrared (FTIR) analyses showed that the AHP pre-hydrolysis was successfully removed hemicelluloses and lignin from the OPF fibre. The crystallinity of the MCC was increased with the AHP concentrations. The degradation temperature of MCC was about 300°C. The finding of the present study showed that pre-treatment process potentially influenced the quality of the isolation of MCC from oil palm fronds. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of water soluble chitosan by hydrolysis using hydrogen peroxide.

Science.gov (United States)

Xia, Zhenqiang; Wu, Shengjun; Chen, Jinhua

2013-08-01

Chitosan is not soluble in water, which limits its wide application particularly in the medicine and food industry. In the present study, water soluble chitosan (WSC) was prepared by hydrolyzing chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid in homogeneous phase. Factors affecting hydrolysis were investigated and the optimal hydrolysis conditions were determined. The WSC structure was characterized by Fourier transform infrared spectroscopy. The resulting products were composed of chitooligosaccharides of DP 2-9. The WSC content of the product and the yield were 94.7% and 92.3% (w/w), respectively. The results indicate that WSC can be effectively prepared by hydrolysis of chitosan using hydrogen peroxide under the catalysis of phosphotungstic acid. Copyright © 2013 Elsevier B.V. All rights reserved.

Amylolytic hydrolysis of native starch granules affected by granule surface area.

Science.gov (United States)

Kim, J C; Kong, B W; Kim, M J; Lee, S H

2008-11-01

Initial stage of hydrolysis of native starch granules with various amylolytic enzymes, alpha-amylase from Bacillus subtilis, glucoamylase I (GA-I) and II (GA-II) from Aspergillus niger, and beta-amylase from sweet potato showed that the reaction was apparently affected by a specific surface area of the starch granules. The ratios of the reciprocal of initial velocity of each amylolytic hydrolysis for native potato and maize starch to that for rice with the amylolytic enzymes were nearly equivalent to the ratio of surface area per mass of the 2 starch granules to that of rice, that is, 6.94 and 2.25, respectively. Thus, the reciprocal of initial velocity of each enzymatic hydrolysis as expressed in a Lineweaver-Burk plot was a linear function of the reciprocal of surface area for each starch granule. As a result, it is concluded that amylolytic hydrolysis of native starch granules is governed by the specific surface area, not by the mass concentration, of each granule.

Effect of γ-irradiation on the acidic hydrolysis of free-hemicellulose thistle

International Nuclear Information System (INIS)

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

1983-01-01

The effect of gamma-irradiation on the subsequent acidic hydrolysis of free-hemicellulose ''Onopordum Nervosum Boiss'' thistle is determined. It is shown the influence of gamma-irradiation on the yield or sugar obtained from the batchwise hydrolysis of the cellulose (1% H 2 SO 4 and 180 0 C) at increasing doses. At all irradiation levels studied, the rate of hydrolysis of thistle samples was higher than the rate of hydrolysis of the cellulose from paper treated similarly. The maximum overall yield of sugar in the irradiated lignocellulosic material was about 66 0 at 100 MRad, less than two times the yield obtainable from the control. The corresponding yield from paper was 53%, 2'3 times that of the control. Irradiation under 1% H 2 SO 4 does not enhance the yield anyway. (author)

Laser-assisted fabrication of materials

CERN Document Server

Manna, Indranil

2013-01-01

Laser assisted fabrication involves shaping of materials using laser as a source of heat. It can be achieved by removal of materials (laser assisted cutting, drilling, etc.), deformation (bending, extrusion), joining (welding, soldering) and addition of materials (surface cladding or direct laser cladding). This book on ´Laser assisted Fabrication’ is aimed at developing in-depth engineering concepts on various laser assisted macro and micro-fabrication techniques with the focus on application and a review of the engineering background of different micro/macro-fabrication techniques, thermal history of the treated zone and microstructural development and evolution of properties of the treated zone.

Recycling cellulases during the hydrolysis of steam exploded and ethanol pretreated Lodgepole pine.

Science.gov (United States)

Tu, Maobing; Chandra, Richard P; Saddler, Jack N

2007-01-01

Recycling of cellulases is one way of reducing the high cost of enzymes during the bioconversion process. The effects of surfactant addition on enzymatic hydrolysis and the potential recycling of cellulases were studied during the hydrolysis of steam exploded Lodgepole pine (SELP) and ethanol pretreated Lodgepole pine (EPLP). Three cellulase preparations (Celluclast, Spezyme CP, and MSUBC) were evaluated to determine their hydrolysis efficiencies over multiple rounds of recycling. The surfactant, Tween 80, significantly increased the yield from 63% to 86% during the hydrolysis of the SELP substrate. The addition of surfactant to the hydrolysis of the EPLP substrate increased the free enzymes in the supernatant from 71% of the initial protein to 96%. Based on the Langmuir adsorption constants, cellulases (Celluclast and Spezyme CP) from Trichoderma reesei showed a higher affinity (3.48 mL/mg and 3.17 mL/mg) for the EPLP substrate than did the Penicillium enzyme (0.62 mg/mg). The Trichoderma reesei enzyme was used in four successive rounds of enzyme recycling using surfactant addition and readsorption onto fresh substrates during the hydrolysis of EPLP. In contrast, the Penicillium-derived enzyme preparation (MSUBC) could only be recycled once. When the same recycling strategy was carried out using the SELP substrate, the hydrolysis yield declined during each enzyme recycling round. These results suggested that the higher lignin content of the SELP substrate, and the low affinity of cellulases for the SELP substrate limited enzyme recycling by readsorption onto fresh substrates.

Kinetics and mechanism of hydrolysis of scandium sulfate

International Nuclear Information System (INIS)

Koshchej, E.V.; Stryapkov, A.V.; Podosenov, D.E.; Makarov, G.V.; Razdobreev, D.A.

1998-01-01

The Sc 2 (SO 4 ) 3 -H 2 SO 4 -H 2 O system is studied through the methods of pH-potentiometry, conductometry and turbidimetry at 298 and 318 K and ion force 0.01, 0.1 and 1.0. The hydrolysis mechanism including the processes in the system homogenous and heterogeneous constituents. The hydrolysis rates of scandium salts and their dependences on OH-ions concentration, solution ions force and temperature are found; the constants of the processes rate with participation of OH - and SO 4 2- ions and constants of the solid phase formation rate are calculated [ru

Kinetics of the methylparathion hydrolysis in aqueous medium

International Nuclear Information System (INIS)

Manzanilla, J.; Barcelo, M.; Reyes, O.

1997-01-01

The kinetics of alkaline hydrolysis of methylparathion was studied at different temperatures (0-50 Centigrade) in the p H range of 8-12 by ultraviolet-visible absorption spectroscopy. Optimum p H and wavelength conditions were defined to carry out the simultaneous determination of methylparathion and one of its hydrolysis product, paranitrophenol, in buffered aqueous medium. Based on the experimental data and the mathematical equation of the kinetics, a rate constant (k) of first-order and an activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author) activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author)

Vanadium(IV)-stimulated hydrolysis of 2,3-diphosphoglycerate.

Science.gov (United States)

Stankiewicz, P J

1989-05-01

Vanadium(IV) stimulates the hydrolysis of 2,3-diphosphoglycerate at 23 degrees C. The pH optimum is 5.0. Reactions were analyzed by enzymatic and phosphate release assays. The products of 2,3-diphosphoglycerate hydrolysis are inorganic phosphate and 3-phosphoglycerate. The reaction is inhibited by high concentrations of 2,3-diphosphoglycerate and an equation has been formulated that describes the kinetic constants for this reaction at pH 7. The possible relevance of the reaction to the therapeutic lowering by vanadium(IV) of red cell 2,3-diphosphoglycerate in sickle-cell disease is discussed.

Development of Volatile Compounds during Hydrolysis of Porcine Hemoglobin with Papain

DEFF Research Database (Denmark)

Bak, Kathrine Holmgaard; Petersen, Mikael Agerlin; Lametsch, Rene

2018-01-01

of volatile compounds with time, e.g., certain Maillard reaction and lipid oxidation products, which are likely candidates for the aroma development during hydrolysis. Furthermore, it was shown that development of a number of the volatiles was due to the hydrolysis process, as these compounds were not found...

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

Directory of Open Access Journals (Sweden)

Happi Emaga, T.

2012-01-01

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

Experimental and numerical study of latent heat thermal energy storage systems assisted by heat pipes for concentrated solar power application

Science.gov (United States)

Tiari, Saeed

A desirable feature of concentrated solar power (CSP) with integrated thermal energy storage (TES) unit is to provide electricity in a dispatchable manner during cloud transient and non-daylight hours. Latent heat thermal energy storage (LHTES) offers many advantages such as higher energy storage density, wider range of operating temperature and nearly isothermal heat transfer relative to sensible heat thermal energy storage (SHTES), which is the current standard for trough and tower CSP systems. Despite the advantages mentioned above, LHTES systems performance is often limited by low thermal conductivity of commonly used, low cost phase change materials (PCMs). Research and development of passive heat transfer devices, such as heat pipes (HPs) to enhance the heat transfer in the PCM has received considerable attention. Due to its high effective thermal conductivity, heat pipe can transport large amounts of heat with relatively small temperature difference. The objective of this research is to study the charging and discharging processes of heat pipe-assisted LHTES systems using computational fluid dynamics (CFD) and experimental testing to develop a method for more efficient energy storage system design. The results revealed that the heat pipe network configurations and the quantities of heat pipes integrated in a thermal energy storage system have a profound effect on the thermal response of the system. The optimal placement of heat pipes in the system can significantly enhance the thermal performance. It was also found that the inclusion of natural convection heat transfer in the CFD simulation of the system is necessary to have a realistic prediction of a latent heat thermal storage system performance. In addition, the effects of geometrical features and quantity of fins attached to the HPs have been studied.

Assessment of methods to determine minimal cellulase concentrations for efficient hydrolysis of cellulose

Energy Technology Data Exchange (ETDEWEB)

Hogan, C.M.; Mes-Hartree, M.; Saddler, J.N. (Forintek Canada Corp., Ottawa, ON (Canada). Biotechnology and Chemistry Dept.); Kushner, D.J. (Toronto Univ., Ontario (Canada). Dept. of Microbiology)

1990-02-01

The enzyme loading needed to achieve substrate saturation appeared to be the most economical enzyme concentration to use for hydrolysis, based on percentage hydrolysis. Saturation was reached at 25 filter paper units per gram substrate on Solka Floc BW300, as determined by studying (a) initial adsorption of the cellulase preparation onto the substrate, (b) an actual hydrolysis or (c) a combined hydrolysis and fermentation (CHF) process. Initial adsorption of the cellulases onto the substrate can be used to determine the minimal cellulase requirements for efficient hydrolysis since enzymes initially adsorbed to the substrate have a strong role in governing the overall reaction. Trichoderma harzianum E58 produces high levels of {beta}-glucosidase and is able to cause high conversion of Solka Floc BW300 to glucose without the need for exogenous {beta}-glucosidase. End-product inhibition of the cellulase and {beta}-glucosidase can be more effectively reduced by employing a CHF process than by supplemental {beta}-glucosidase. (orig.).

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

Science.gov (United States)

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

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

Science.gov (United States)

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.

Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

Science.gov (United States)

Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

2011-03-01

Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

Adsorption of monocomponent enzymes in enzyme mixture analyzed quantitatively during hydrolysis of lignocellulose substrates.

Science.gov (United States)

Várnai, Anikó; Viikari, Liisa; Marjamaa, Kaisa; Siika-aho, Matti

2011-01-01

The adsorption of purified Trichoderma reesei cellulases (TrCel7A, TrCel6A and TrCel5A) and xylanase TrXyn11 and Aspergillus niger β-glucosidase AnCel3A was studied in enzyme mixture during hydrolysis of two pretreated lignocellulosic materials, steam pretreated and catalytically delignified spruce, along with microcrystalline cellulose (Avicel). The enzyme mixture was compiled to resemble the composition of commercial cellulase preparations. The hydrolysis was carried out at 35 °C to mimic the temperature of the simultaneous saccharification and fermentation (SSF). Enzyme adsorption was followed by analyzing the activity and the protein amount of the individual free enzymes in the hydrolysis supernatant. Most enzymes adsorbed quickly at early stages of the hydrolysis and remained bound throughout the hydrolysis, although the conversion reached was fairly high. Only with the catalytically oxidized spruce samples, the bound enzymes started to be released as the hydrolysis degree reached 80%. The results based on enzyme activities and protein assay were in good accordance. Copyright © 2010 Elsevier Ltd. All rights reserved.

Mechanisms of the stimulatory effects of rhamnolipid biosurfactant on rice straw hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiuzhuo; He, Guofu; Xu, Yatong [Department of Environmental Science, East China Normal University, 3663 North Zhongshan Road, Putuo District, Shanghai 200062 (China); Wang, Juan [Department of Environmental Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); Cai, Weimin [Department of Environmental Science and Engineering, Harbin Institute of Technology, Harbin 150090 (China); School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

2009-11-15

Rhamnolipid biosurfactant, as an addition to rice straw hydrolysis bioprocess, could not only stimulate the hydrolysis rate, but also reduce the requirement for large amount of cellulases and promote its recycling process. In this article, through the observation of the changes of cellulases, microorganism, substrate and their mutual functions, the mechanisms of the stimulatory effect of rhamnolipid on rice straw hydrolysis were investigated. The study found that the addition of rhamnolipid increases the activity of {beta}-glucosidase but stabilizes Cel7A activity. The observed results might be the main mechanisms triggering the stimulatory effect of adding biosurfactants on rice straw hydrolysis. Meanwhile, zeta potential of the substrate increased, which could make the resistance of the cell attached to the substrate weaker. This in turn could facilitate easy adhesion and better retention of the microbial cell in the media. Moreover, we discovered that lignin content played an important role in the stimulatory effect of adding rhamnolipid. The adsorption of rhamnolipid biosurfactant prevented unproductive binding of enzymes to lignin. This could be another important mechanism responsible for the stimulatory effects of adding rhamnolipid on rice straw hydrolysis. (author)

Lactose hydrolysis by free and fibre-entrapped β-galactosidase from Streptococcus thermophilus

Directory of Open Access Journals (Sweden)

Zhennai Yang

1993-09-01

Full Text Available To study lactose hydrolysis by β-galactosidase, this enzyme was produced from Streptococcus thermophilus strain 11F and partially purified by acetone and ammonium sulphate fractionation, and ion exchange chromatography on a Q Sepharose FF column. Lactose hydrolysis by the enzyme was affected by lactose concentrations, sugars and milk proteins. The maximum extent of lactose hydrolysis in buffer was obtained with a 15% lactose concentration. Addition of 2% of lactose, glucose, galactose or sucrose in milk inhibited the enzymatic hydrolysis. The enzyme was activated by bovine serum albumin and a combination of αs-casein and β-casein. Of the casein fractions, the principal fraction, αs-casein, was less effective than β-casein and κ-casein. The fibre entrapped enzyme had a temperature optimum of 57°C, and a pH optimum from 7.5 to at least 9.0 with O-nitrophenyl-β-D-galactopyranoside as substrate. By recycling with whey and skim milk through a jacketed glass column (1.6 cm x 30 cm loaded with fibre-entrapped enzyme at 55°C, a lactose hydrolysis of 49.5% and 47.9% was achieved in 11 h and 7 h respectively.

Aqueous-gas phase partitioning and hydrolysis of organic iodides

International Nuclear Information System (INIS)

Glowa, G.A.; Wren, J.C.

2003-01-01

The volatility and decomposition of organic iodides in a reactor containment building are important parameters to consider when assessing the potential consequences of a nuclear reactor accident. However, there are few experimental data available for the volatilities (often reported as partition coefficients) or few rate constants regarding the decomposition (via hydrolysis) of organic iodides. The partition coefficients and hydrolysis rate constants of eight organic iodides, having a range of molecular structures, have been measured in the current studies. This data, and data accumulated in the literature, have been reviewed and discussed to provide guidelines for appropriate organization of organic iodides for the purpose of modelling iodine behaviour under postulated nuclear reactor accident conditions. After assessment of the partition coefficients and their temperature dependences of many classes of organic compounds, it was found that organic iodides could be divided into two categories based upon their volatility relative to molecular iodine. Similarly, hydrolysis rates and their temperature dependences are assigned to the two categories of organic iodides. (author)

Effect of Hydrolysis Products of Different Proteins of Wheat on Antioxidant Enzymes

Directory of Open Access Journals (Sweden)

Hasan Hasanov

2011-05-01

Full Text Available This paper presents a study of the effect of products of enzymatic hydrolysis of various proteins of wheat with a neutral proteinase (neutrase “Novozymes”, Denmark on the activity of peroxidase from horseradish. It is shown that the hydrolysis products of albumin activate peroxidase activity, the constant of activation being 2.3 micromoles. At the same time with increasing the depth of hydrolysis of albumin the activating effect of peptides disappears. Peptides derived from the salt-soluble, alcohol-soluble alkali-soluble proteins had no effect on the activity of peroxidase.

Ultrafast Formation of ZnO Nanorods via Seed-Mediated Microwave Assisted Hydrolysis Process

International Nuclear Information System (INIS)

Tan, S T; Yahaya, M; Yap, C C; Umar, A A; Salleh, M M

2013-01-01

One dimensional (1D) zinc oxide, ZnO nanostructures have shown promising results for usage in photodiode and optoelectronic device due to their high surface area. Faster and conventional method for synthesis ZnO nanorods has become an attention for researcher today. In this paper, ZnO nanorods have been successfully synthesized via two-step process, namely alcothermal seeding and seed-mediated microwave hydrolysis process. In typical process, the ZnO nanoseeds were grown in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate, Zn (NO 3 ).6H 2 O and hexamethylenetetramine, HMT. The growth process was carried inside the inverted microwave within 5- 20 s. The effect of growth parameters (i.e. concentration, microwave power, time reaction) upon the modification of ZnO morphology was studied. ZnO nanostructures were characterized by Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). The densities of nanorods were evaluated by the Image J analysis. It was found that the morphology (e.g. shape and size) of nanostructures has changed drastically with the increment of growth solution concentration. The density of ZnO nanorods was proven to increase with the increasing of reaction time and microwave power. We hypothesize that the microwave power might enhance the rate of nucleation and promote the faster nanostructure growth as compared with the normal heating condition due to the superheating phenomenon. This method might promote a new and faster alternative way in nanostructure growth which can be applied in currently existing application.

Ultrafast Formation of ZnO Nanorods via Seed-Mediated Microwave Assisted Hydrolysis Process

Science.gov (United States)

Tan, S. T.; Umar, A. A.; Yahaya, M.; Yap, C. C.; Salleh, M. M.

2013-04-01

One dimensional (1D) zinc oxide, ZnO nanostructures have shown promising results for usage in photodiode and optoelectronic device due to their high surface area. Faster and conventional method for synthesis ZnO nanorods has become an attention for researcher today. In this paper, ZnO nanorods have been successfully synthesized via two-step process, namely alcothermal seeding and seed-mediated microwave hydrolysis process. In typical process, the ZnO nanoseeds were grown in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate, Zn (NO3).6H2O and hexamethylenetetramine, HMT. The growth process was carried inside the inverted microwave within 5- 20 s. The effect of growth parameters (i.e. concentration, microwave power, time reaction) upon the modification of ZnO morphology was studied. ZnO nanostructures were characterized by Field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). The densities of nanorods were evaluated by the Image J analysis. It was found that the morphology (e.g. shape and size) of nanostructures has changed drastically with the increment of growth solution concentration. The density of ZnO nanorods was proven to increase with the increasing of reaction time and microwave power. We hypothesize that the microwave power might enhance the rate of nucleation and promote the faster nanostructure growth as compared with the normal heating condition due to the superheating phenomenon. This method might promote a new and faster alternative way in nanostructure growth which can be applied in currently existing application.

Facile fabrication of a stable and recyclable lipase@amine-functionalized ZIF-8 nanoparticles for esters hydrolysis and transesterification

Science.gov (United States)

Cheong, Ling-Zhi; Wei, Yayu; Wang, Hongbin; Wang, Zhiying; Su, Xiurong; Shen, Cai

2017-08-01

Zeolitic imidazolate frameworks (ZIF) represent one of the metal organic frameworks (MOF) with high potential for enzyme immobilization due to their exceptional chemical and thermal stability, negligible cytotoxicity, and easy synthesis under mild biocompatible conditions. Amine-functionalized ZIF-8 (An-ZIF-8) are capable of forming multipoint attachment via hydrogen bonding with lipase which will immobilize and further enhance stabilization of lipase. In addition, increased hydrophilicity of An-ZIF-8 will increase partitioning of An-ZIF-8 immobilized lipase at the aqueous/organic interface which enable lipase to expose its active site and retain its catalytic activity at its highest. Present study reports the use of ZIF-8 and An-ZIF-8 nanoparticles as carrier for Burkholderia cepacia lipase (BCL), compares the ester hydrolysis and transesterification activities of immobilized lipase with those of free lipase, and evaluates the reusability and recovery rate of the immobilized lipase. An-ZIF-8 nanoparticles (average 130.42 ± 0.55 nm) were facilely synthesized via mixing ZIF-8 nanoparticles with ammonia hydroxide solution. Despite having similar characteristics of high crystallinity and forming cuboid-like particles, An-ZIF-8 demonstrated significantly ( P hydrolysis and transesterification activities with those of free BCL. BCL@An-ZIF-8 demonstrated superior catalytic stability in comparison to BCL@ZIF-8 with retainment of more than 80% of its initial hydrolysis and transesterification activity for at least 10 repeated runs. In addition, more than 80% of the BCL@An-ZIF-8 can be easily recovered during each cycle of the reusability test through simple centrifugation.

Synthesis and Photophysical Characterizations of Thermal -Stable Naphthalene Benzimidazoles

OpenAIRE

Erten Ela, Şule; Özçelik, Serdar; Eren, Ersin

2011-01-01

Microwave-assisted synthesis, photophysical and electrochemical properties of thermal-stable naphthalene benzimidazoles and naphthalimides are studied in this paper. Microwave-assisted synthesis of naphthalene benzimidazoles provide higher yields than the conventional thermal synthesis. Comparative photophysical properties of naphthalene benzimidazoles and naphthalimides are revealed that conjugation of electron-donating group onto naphthalimide moiety increases fluorescence ...

HYDROLYSIS OF HALOACETONITRILES: LINEAR FREE ENERGY RELATIONSHIP, KINETICS AND PRODUCTS. (R825362)

Science.gov (United States)

AbstractThe hydrolysis rates of mono-, di- and trihaloacetonitriles were studied in aqueous buffer solutions at different pH. The stability of haloacetonitriles decreases and the hydrolysis rate increases with increasing pH and number of halogen atoms in the molecule:...

Ruminal bacteria and protozoa composition, digestibility, and amino acid profile determined by multiple hydrolysis times.

Science.gov (United States)

Fessenden, S W; Hackmann, T J; Ross, D A; Foskolos, A; Van Amburgh, M E

2017-09-01

Microbial samples from 4 independent experiments in lactating dairy cattle were obtained and analyzed for nutrient composition, AA digestibility, and AA profile after multiple hydrolysis times ranging from 2 to 168 h. Similar bacterial and protozoal isolation techniques were used for all isolations. Omasal bacteria and protozoa samples were analyzed for AA digestibility using a new in vitro technique. Multiple time point hydrolysis and least squares nonlinear regression were used to determine the AA content of omasal bacteria and protozoa, and equivalency comparisons were made against single time point hydrolysis. Formalin was used in 1 experiment, which negatively affected AA digestibility and likely limited the complete release of AA during acid hydrolysis. The mean AA digestibility was 87.8 and 81.6% for non-formalin-treated bacteria and protozoa, respectively. Preservation of microbe samples in formalin likely decreased recovery of several individual AA. Results from the multiple time point hydrolysis indicated that Ile, Val, and Met hydrolyzed at a slower rate compared with other essential AA. Singe time point hydrolysis was found to be nonequivalent to multiple time point hydrolysis when considering biologically important changes in estimated microbial AA profiles. Several AA, including Met, Ile, and Val, were underpredicted using AA determination after a single 24-h hydrolysis. Models for predicting postruminal supply of AA might need to consider potential bias present in postruminal AA flow literature when AA determinations are performed after single time point hydrolysis and when using formalin as a preservative for microbial samples. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Enzymatic activity of the cellulolytic complex produced by trichoderma reesei. Enzymatic hydrolysis of cellulose

International Nuclear Information System (INIS)

Alfonsel Jaen, M.; Negro, M.J.; Saez, R.; Martin Moreno, C.

1986-01-01

The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reese QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass from Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars productions, have been selected. Previous studies on enzymatic hydrolysis of O. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (author). 10 figs.; 10 refs

Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose

International Nuclear Information System (INIS)

Alfonsel J, M.; Negro A, M. J.; Saez A, R.; Martin M, C.

1986-01-01

The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs

Systematic comparison of mechanical and thermal sludge disintegration technologies.

Science.gov (United States)

Wett, B; Phothilangka, P; Eladawy, A

2010-06-01

This study presents a systematic comparison and evaluation of sewage sludge pre-treatment by mechanical and thermal techniques. Waste activated sludge (WAS) was pre-treated by separate full scale Thermo-Pressure-Hydrolysis (TDH) and ball milling facilities. Then the sludge was processed in pilot-scale digestion experiments. The results indicated that a significant increase in soluble organic matter could be achieved. TDH and ball milling pre-treatment could offer a feasible treatment method to efficiently disintegrate sludge and enhance biogas yield of digestion. The TDH increased biogas production by ca. 75% whereas ball milling allowed for an approximately 41% increase. The mechanisms of pre-treatment were investigated by numerical modeling based on Anaerobic Digestion Model No. 1 (ADM1) in the MatLab/SIMBA environment. TDH process induced advanced COD-solubilisation (COD(soluble)/COD(total)=43%) and specifically complete destruction of cell mass which is hardly degradable in conventional digestion. While the ball mill technique achieved a lower solubilisation rate (COD(soluble)/COD(total)=28%) and only a partial destruction of microbial decay products. From a whole-plant prospective relevant release of ammonia and formation of soluble inerts have been observed especially from thermal hydrolysis. Copyright 2009 Elsevier Ltd. All rights reserved.

Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel.

Science.gov (United States)

Park, Jeongseok; Kim, Bora; Son, Jeesung; Lee, Jae W

2018-02-01

This work addresses non-catalytic biodiesel production from spent coffee ground (SCG) by integrating solvo-thermal effect of 1,2-dichloroethane (DCE) with in situ transesterification over 160 °C. The SCG water content has a positive effect on the DCE hydrolysis up to 60 wt% due to the bimolecular substitution mechanism. The hydrolysis gives an acidic environment favorable for cellulose decomposition, SCG particle size reduction and lipid conversion. The optimal fatty acid ethyl ester yield was 11.8 wt% based on the mass of dried SCG with 3.36 ml ethanol and 3.16 ml DCE at 196.8 °C through the response surface methodology. Using the solvo-thermal effect, direct utilization of wet SCG as a biodiesel feedstock provides not only economic feasibility without using drying process and additional acid catalyst but also environmental advantage of recycling the municipal waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

Kinetic Control of Aqueous Hydrolysis: Modulating Structure/Property Relationships in Inorganic Crystals

Science.gov (United States)

Neilson, James R.

2011-12-01

A grand challenge in materials science and chemistry revolves around the preparation of materials with desired properties by controlling structure on multiple length scales. Biology approaches this challenge by evolving tactics to transform soluble precursors into materials and composites with macro-scale and atomic precision. Studies of biomineralization in siliceous sponges led to the discovery of slow, catalytic hydrolysis of molecular precursors in the biogenesis of silica skeletal elements with well defined micro- and nano-scale architectures. However, the role of aqueous hydrolysis in the limit of kinetic control is not well understood; this allows us to form a central hypothesis: that the kinetics of hydrolysis modulate the structures of materials and their properties. As a model system, the diffusion of a simple hydrolytic catalyst (such as ammonia) across an air-water interface into a metal salt solution reproduces some aspects of the chemistry found in biomineralization, namely kinetic and vectorial control. Variation of the catalyst concentration modulates the hydrolysis rate, and thus alters the resulting structure of the inorganic crystals. Using aqueous solutions of cobalt(II) chloride, each product (cobalt hydroxide chloride) forms with a unique composition, despite being prepared from identical mother liquors. Synchrotron X-ray total scattering methods are needed to locate the atomic positions in the material, which are not aptly described by a traditional crystallographic unit cell due to structural disorder. Detailed definition of the structure confirms that the hydrolysis conditions systematically modulate the arrangement of atoms in the lattice. This tightly coupled control of crystal formation and knowledge of local and average structures of these materials provides insight into the unusual magnetic properties of these cobalt hydroxides. The compounds studied show significant and open magnetization loops with little variation with composition

Optimization of enzymatic hydrolysis and fermentation conditions for improved bioethanol production from potato peel residues.

Science.gov (United States)

Ben Taher, Imen; Fickers, Patrick; Chniti, Sofien; Hassouna, Mnasser

2017-03-01

The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 g L -1 of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30 g L -1 after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:397-406, 2017. © 2017 American Institute of Chemical Engineers.

Cross-synergism in enzymatic hydrolysis of lignocellulosics: mathematical correlations according to a hyperbolic model

Energy Technology Data Exchange (ETDEWEB)

Tarantili, P.A.; Koullas, D.P.; Christakopoulos, P.; Kekos, D.; Koukios, E.G.; Macris, B.J. [National Technical Univ. of Athens (Greece). Dept. of Chemical Engineering

1996-10-01

The effect of cross-synergism in enzymatic hydrolysis of ball-milled Avicell, alkali-treated straw cellulose (ATSC), cotton and filter paper was investigated using mixtures of Fusarium oxysporum and Neurospora crassa enzymes. The experimental data were fitted according to an empirical hyperbolic model which utilized two parameters, the maximum conversion ({chi}{sub max}) and the enzymatic hydrolysis time corresponding to 50% of {chi}{sub max} (t{sub 1/2}). The model can predict conversion of polysaccharides as a function of hydrolysis time. Both model parameters were found to be strongly dependent on the crystallinity index as well as on the degree of delignification of the substrate. Up to 60% cellulose hydrolysis can be achieved when the crystallinity index of Avicell is reduced from 94.8% to 63.3%. The percentage increase of {chi}{sub max} due to delignification was higher than the corresponding increase of t{sub 1/2}. The extent of cross-synergism depends strongly on crystallinity index and degree of delignification. This type of synergism has been found to be significant in the case of substrates which are resistant to hydrolysis, such as Avicell (with high crystallinity index) or cotton. Cross-synergism phenomena caused by enzymatic mixtures can double cellulose hydrolysis yield with delignified straw as compared to the hydrolysis yields achieved by single-microorganism cellulases. (author)

Phospholipase C-catalyzed sphingomyelin hydrolysis in a membrane reactor for ceramide production

DEFF Research Database (Denmark)

Zhang, Long; Liang, Shanshan; Hellgren, Lars

2008-01-01

A membrane reactor for the production of ceramide through sphingomyelin hydrolysis with phospholipase C from Clostridium perfringens was studied for the first time. Ceramide has raised a large interest as an active component in both pharmaceutical and cosmetic industry. The enzymatic hydrolysis...

Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

Science.gov (United States)

Corredor, Deisy Y.

The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis

Immobilization of Aspergillus niger cellulase on multiwall carbon nanotubes for cellulose hydrolysis.

Science.gov (United States)

Ahmad, Razi; Khare, Sunil Kumar

2018-03-01

In present study, Aspergillus niger cellulase was immobilized onto functionalized multiwalled carbon nanotubes (MWCNTs) via carbodiimide coupling. MWCNTs offer unique advantages including enhanced electronics properties, a large edge to basal plane ratio, rapid electrode kinetics and it's possess higher tensile strength properties due to their structural arrangements. The immobilization was confirmed by FTIR (Fourier transform infrared spectroscopy) and SEM (scanning electron microscope). The bionanoconjugates prepared under optimized condition retained 85% activity with improved pH and thermal stability. The t 1/2 of immobilized cellulase at 70 °C was four fold higher than free enzyme. The Km value indicates that affinity of bionanoconjugates towards substrate has increased by two times. The preparation could be reused ten times without much loss in enzyme activity. The enhanced catalytic efficiency, stability and reusability makes it useful for efficient cellulose hydrolysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Catalytic hydrolysis of ammonia borane: Intrinsic parameter estimation and validation

Energy Technology Data Exchange (ETDEWEB)

Basu, S.; Gore, J.P. [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-2088 (United States); School of Chemical Engineering, Purdue University, West Lafayette, IN 47907-2100 (United States); Energy Center in Discovery Park, Purdue University, West Lafayette, IN 47907-2022 (United States); Zheng, Y. [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-2088 (United States); Energy Center in Discovery Park, Purdue University, West Lafayette, IN 47907-2022 (United States); Varma, A.; Delgass, W.N. [School of Chemical Engineering, Purdue University, West Lafayette, IN 47907-2100 (United States); Energy Center in Discovery Park, Purdue University, West Lafayette, IN 47907-2022 (United States)

2010-04-02

Ammonia borane (AB) hydrolysis is a potential process for on-board hydrogen generation. This paper presents isothermal hydrogen release rate measurements of dilute AB (1 wt%) hydrolysis in the presence of carbon supported ruthenium catalyst (Ru/C). The ranges of investigated catalyst particle sizes and temperature were 20-181 {mu}m and 26-56 C, respectively. The obtained rate data included both kinetic and diffusion-controlled regimes, where the latter was evaluated using the catalyst effectiveness approach. A Langmuir-Hinshelwood kinetic model was adopted to interpret the data, with intrinsic kinetic and diffusion parameters determined by a nonlinear fitting algorithm. The AB hydrolysis was found to have an activation energy 60.4 kJ mol{sup -1}, pre-exponential factor 1.36 x 10{sup 10} mol (kg-cat){sup -1} s{sup -1}, adsorption energy -32.5 kJ mol{sup -1}, and effective mass diffusion coefficient 2 x 10{sup -10} m{sup 2} s{sup -1}. These parameters, obtained under dilute AB conditions, were validated by comparing measurements with simulations of AB consumption rates during the hydrolysis of concentrated AB solutions (5-20 wt%), and also with the axial temperature distribution in a 0.5 kW continuous-flow packed-bed reactor. (author)

Equilibrium method for estimating the first hydrolysis constant of tetravalent plutonium

International Nuclear Information System (INIS)

Silver, G.L.

2010-01-01

A new method for estimating the numerical value of the first hydrolysis constant of tetravalent plutonium is illustrated by examples. It uses the pH and the equilibrium fractions of two of the Pu oxidation states. They are substituted into one or more of a choice of formulas that render explicit estimates of the hydrolysis constant. (author)

Kinetic and thermodynamic analysis of 10-hydroxy-camptothecin hydrolysis at physiological pH

Energy Technology Data Exchange (ETDEWEB)

Kunadharaju, Sasank [Division of Pharmaceutical Sciences, Arnold and Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, NY 11201 (United States); Savva, Michalakis [Division of Pharmaceutical Sciences, Arnold and Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, NY 11201 (United States)], E-mail: msavva@liu.edu

2008-09-15

To derive accurately the thermodynamic parameters governing the hydrolysis of the lactone ring at physiological pH, a derivative spectrophotometric technique was used for the simultaneous estimation of lactone and carboxylate forms of the 10-hydroxy-camptothecin (10-HC). Validation of the analytical method was done with respect to reproducibility, percent recovery, and level of detection. Hydrolysis of the lactone ring of 10-HC followed a 1st order decay with a rate constant equal to (0.0281 {+-} 0.001) min{sup -1} in PBS at pH 7.4 and at a temperature of 310 K. The activation energy for the hydrolysis reaction as calculated from the Arrhenius equation was (79.41 {+-} 0.92) kJ . mol{sup -1}, whereas the enthalpy and entropy of hydrolysis of 10-hydroxy-camptothecin were on average 12.45 kJ . mol{sup -1} and 52.37 J . K{sup -1} . mol{sup -1}, respectively. The positive enthalpy and entropy values of the 10-HC-lactone hydrolysis indicate that the reaction is endothermic and entropically driven.

Thionyl chloride assisted functionalization of amorphous carbon nanotubes: A better field emitter and stable nanofluid with better thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Sarkar, S.K.; Jha, A. [School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700 032 (India); Chattopadhyay, K.K., E-mail: kalyan_chattopadhyay@yahoo.com [Thin Film & Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700 032 (India); School of Materials Science and Nanotechnology, Jadavpur University, Kolkata 700 032 (India)

2015-06-15

Highlights: • Thionyl chloride assisted functionalization of amorphous carbon nanotubes (a-CNTs). • Improved dispersion enhanced thermal conductivity of engine oil. • Again f-a-CNTs showed enhanced field emission property compared to pure a-CNTs. - Abstract: Amorphous carbon nanotubes (a-CNTs) were synthesized at low temperature in open atmosphere and further functionalized by treating them in thionyl chloride added stearic acid-dichloro methane solution. The as prepared functionalized a-CNTs (f-a-CNTs) were characterized by Raman spectroscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, transmission and scanning electron microscopy. The nanofluid was prepared by dispersing f-a-CNTs in engine oil using ultrasonic treatment. The effective thermal conductivity of as prepared nanofluid was investigated at different loading (volume fraction of f-a-CNTs). Obtained experimental data of thermal conductivity were compared with the predicted values, calculated using existing theoretical models. Stability of the nanofluid was tested by means of zeta potential measurement to optimize the loading. The as prepared f-a-CNTs sample also showed improved field emission result as compared to pristine a-CNTs. Dependence of field emission behavior on inter electrode distance was investigated too.

Impact of initial biodegradability on sludge anaerobic digestion enhancement by thermal pretreatment.

Science.gov (United States)

Carrère, Hélène; Bougrier, Claire; Castets, Delphine; Delgenès, Jean Philippe

2008-11-01

Thermal treatments with temperature ranging from 60 to 210 degrees C were applied to 6 waste-activated sludge samples originating from high or medium load, extended aeration wastewater treatment processes that treated different wastewaters (urban, urban and industrial or slaughterhouse). COD sludge solubilisation was linearly correlated with the treatment temperature on the whole temperature range and independently of the sludge samples. Sludge batch mesophilic biodegradability increased with treatment temperature up to 190 degrees C. In this temperature range, biodegradability enhancement or methane production increase by thermal hydrolysis was shown to be a function of sludge COD solubilisation but also of sludge initial biodegradability. The lower the initial biodegradability means the higher efficiency of thermal treatment.

Efficient Hydrolysis of Rice Straw into Xylose and Glucose by a Two-step Process

Directory of Open Access Journals (Sweden)

YAN Lu-lu

2016-07-01

Full Text Available The hydrolysis of rice straw into xylose and glucose in dilute sulfuric acid aqueous solution was studied with a two-step process in batch autoclave reactor. The results showed that compared with the traditional one-step acid hydrolysis, both xylose and glucose could be produced in high yields from rice straw by using the two-step acid hydrolysis process. The effects of reaction temperature, reaction time, the amount of rice straw and acid concentration on the hydrolysis of rice straw were systematically studied, and showed that except initial rice straw loading amount, the other parameters had remarkable influence on the products distribution and yields. In the first-step of the hydrolysis process, a high xylose yield of 162.6 g·kg-1 was obtained at 140℃ after 120 min reaction time. When the solid residues from the first step were subjected to a second-step hydrolysis, a glucose yield as high as 216.5 g·kg-1 could be achieved at 180℃ after 120 min. This work provides a promising strategy for the efficient and value-added utilization of agricultural wastes such as rice straw.

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

NARCIS (Netherlands)

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

2007-01-01

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

Pretreatment of sawdust and its hydrolysis with immobilised enzymes

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1988-01-01

The pretreatment of sawdust by radiation and its hydrolysis with immobilised cellulase were studied. The sawdust was irradiated with a number of different irradiation doses and crushed with two kinds of crusher; pulveriser and ball mill. In ball-mill crushing, the crushing time to get a fine powder was reduced by radiation treatment and the conversion yield of cellulose to glucose in the enzyme hydrolysis was increased. It was found that sawdust pretreated by radiation and subsequent crushing was efficiently hydrolysed by immobilised cellulase which itself was obtained by a radiation polymerisation technique. (author)

Analysis of myo-inositol hexakisphosphate hydrolysis by Bacillus phytase

DEFF Research Database (Denmark)

Kerovuo, J.; Rouvinen, J.; Hatzack, Frank-Andreas

2000-01-01

Phytic acid (myo-inositol hexakisphosphate, InsP(6)) hydrolysis by Bacillus phytase (PhyC) was studied. The enzyme hydrolyses only three phosphates from phytic acid. Moreover, the enzyme seems to prefer the hydrolysis of every second phosphate over that of adjacent ones. Furthermore, it is very...... a reaction mechanism different from that of other phytases. By combining the data presented in this study with (1) structural information obtained from the crystal structure of Bacillus amyloliquefaciens phytase [Ha, Oh, Shin, Kim, Oh, Kim, Choi and Oh (2000) Nat. Struct. Biol. 7, 147-153], and (2) computer...

Catalytic hydrolysis of Metil Teret Botil Eter in under ground contaminated water

International Nuclear Information System (INIS)

Nikpey, A.; Mortazavi, B.; Asilian, H.; Khavanin, A.; Rezaee, A.; Soleimanian, A.; Kazemian, H.

2005-01-01

The behavior of ZSM-5 and Mordenite catalyst in the hydrolysis at room temperature of methyl tert-butyl ether was studied with reference to the possibility of its conversion to more biodegradable products in underground water contaminated by methyl tert-butyl ether. Hydrolysis products were determined using a gas chromatograph equipped with a flame ionization detector. The results indicate that acid ZSM-5 catalyst are effective in both adsorption and hydrolysis of methyl tert-butyl ether and may be applied for both in situ underground water remediation and as protection barrier for wells or leaking tanks. However, acid mordenite catalyst completely inactive

High-solids loading enzymatic hydrolysis of waste papers for biofuel production

International Nuclear Information System (INIS)

Wang, Lei; Templer, Richard; Murphy, Richard J.

2012-01-01

Highlights: ► Waste papers have great potential as a feedstock for bioethanol production. ► A wet blending step would significantly enhance enzymatic hydrolysis efficiency. ► High-solids loading saccharification was performed successfully on waste papers. ► Saccharification data were from four types of paper and two enzyme alternatives. ► Enzymatic hydrolysis kinetic models were validated by experimental data. -- Abstract: Waste papers (newspaper, office paper, magazines and cardboard in this study) with 50–73% (w/w oven dry weight) carbohydrate contents have considerable potential as raw materials for bioethanol production. A particle size reduction step of wet blending prior to enzymatic hydrolysis of newspaper was found to increase the glucan conversion efficiency by up to 10%. High-solids loading hydrolysis at 15% (w/w) of four types of paper using two enzyme alternatives, Celluclast 1.5L supplemented with Novozyme 188 and Cellic Ctec 1 (Novozymes A/S, Demark), at various enzyme concentrations were successfully performed in a lab-scale overhead-stirred reactor. This work has identified the relative saccharification performance for the four types of paper and shows office paper and cardboard to be more suitable for producing bioethanol than newspaper or magazine paper. The experimental data were also very well described by a modified, simple three parameter glucan and xylan hydrolysis model. These findings provide the possibility for incorporating this validated kinetic model into process designs required for commercial scale bioethanol production from waste paper resources.

Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

Science.gov (United States)

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. Copyright © 2011 Elsevier Ltd. All rights reserved.

Starch facilitates enzymatic wheat gluten hydrolysis

NARCIS (Netherlands)

Hardt, N.A.; Boom, R.M.; Goot, van der A.J.

2015-01-01

Wheat gluten can be hydrolyzed by either using (vital) wheat gluten or directly from wheat flour. This study investigates the influence of the presence of starch, the main component of wheat, on enzymatic wheat gluten hydrolysis. Wheat gluten present in wheat flour (WFG) and vital wheat gluten (VWG)

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

Science.gov (United States)

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.

Improving enzymatic hydrolysis of industrial hemp (Cannabis sativa L.) by electron beam irradiation

International Nuclear Information System (INIS)

Shin, Soo-Jeong; Sung, Yong Joo

2008-01-01

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose

Improving enzymatic hydrolysis of industrial hemp ( Cannabis sativa L.) by electron beam irradiation

Science.gov (United States)

Shin, Soo-Jeong; Sung, Yong Joo

2008-09-01

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

Improving enzymatic hydrolysis of industrial hemp (Cannabis sativa L.) by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Shin, Soo-Jeong [Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Sung, Yong Joo [KT and G Central Research Institute, 302 Shinseong-Dong, Yuseong-Gu, Daejeon 305-805 (Korea, Republic of)], E-mail: yosung17@yahoo.co.kr

2008-09-15

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

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

Directory of Open Access Journals (Sweden)

Woiciechowski Adenise Lorenci

2002-01-01

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

High yield hydrolysis of seaweed-waste biomass using peracetic acid and ionic liquid treatments

Science.gov (United States)

Uju, Wijayanta, Agung Tri; Goto, Masahiro; Kamiya, Noriho

2018-02-01

Seaweed is one of the most promising bioethanol feedstocks. This water plant has high carbohydrate content but low lignin content, as a result it will be easier to be hydrolysed. This paper described hydrolysis of seaweed-waste biomass from the carrageenan (SWBC) industry using enzymatic saccharification or ionic liquids-HCl hydrolysis. In the first work, SWBC pretreated by peracetic acid (PAA) followed by ionic liquid (IL) caused enhance the cellulose conversion of enzymatic saccharification. At 48h saccharification, the value conversion almost reached 100%. In addition, the untreated SWBC also produced the cellulose conversion 77%. In the second work, SWBC or Bagasse with or without pretreated by PAA was hydrolyzed using ILs-HCl hydrolysis. The ILs used were 1-buthyl-3-methylpyridium chloride, [Bmpy][Cl] and 1-butyl-3-metyl imidazolium chloride ([Bmim][Cl]). [Bmpy][Cl]-HCl hydrolysis produced higher cellulose conversion than [Bmim][Cl]-HCl hydrolysis. The phenomenon was clearly observed on the Bagasse, which without pretreated by PAA. Furthermore, SWBC hydrolyzed by both ILs in the presence low concentration of HCl produced cellulose conversion 70-98% at 60-90 min of hydrolysis time. High cellulose conversion of SWBC on the both hydrolysis was caused by SWBC had the low lignin (4%). Moreover, IL treatments caused lowering of cellulose hydrogen bonds or even changed the cellulose characteristics from cellulose I to cellulose II which easily to be hydrolyzed. In the case of [Bmpy][Cl], this IL may reduce the degree polymerization of celluloses.

Origin Licensing Requires ATP Binding and Hydrolysis by the MCM Replicative Helicase

Science.gov (United States)

Coster, Gideon; Frigola, Jordi; Beuron, Fabienne; Morris, Edward P.; Diffley, John F.X.

2014-01-01

Summary Loading of the six related Minichromosome Maintenance (MCM) proteins as head-to-head double hexamers during DNA replication origin licensing is crucial for ensuring once-per-cell-cycle DNA replication in eukaryotic cells. Assembly of these prereplicative complexes (pre-RCs) requires the Origin Recognition Complex (ORC), Cdc6, and Cdt1. ORC, Cdc6, and MCM are members of the AAA+ family of ATPases, and pre-RC assembly requires ATP hydrolysis. Here we show that ORC and Cdc6 mutants defective in ATP hydrolysis are competent for origin licensing. However, ATP hydrolysis by Cdc6 is required to release nonproductive licensing intermediates. We show that ATP binding stabilizes the wild-type MCM hexamer. Moreover, by analyzing MCM containing mutant subunits, we show that ATP binding and hydrolysis by MCM are required for Cdt1 release and double hexamer formation. This work alters our view of how ATP is used by licensing factors to assemble pre-RCs. PMID:25087873

Switching catalysis from hydrolysis to perhydrolysis in P. fluorescens esterase

Science.gov (United States)

Yin, De Lu (Tyler); Bernhardt, Peter; Morley, Krista L.; Jiang, Yun; Cheeseman, Jeremy D.; Purpero, Vincent; Schrag, Joseph D.; Kazlauskas, Romas J.

2010-01-01

Many serine hydrolases catalyze perhydrolysis – the reversible formation of per-acids from carboxylic acids and hydrogen peroxide. Recently we showed that a single amino acid substitution in the alcohol binding pocket - L29P - in Pseudomonas fluorescens (SIK WI) aryl esterase (PFE) increased the specificity constant of PFE for peracetic acid formation >100-fold [Bernhardt et al. Angew. Chem. Intl. Ed. 2005, 44, 2742]. In this paper, we extend this work to address the three following questions. First, what is the molecular basis of the increase in perhydrolysis activity? We previously proposed that the L29P substitution creates a hydrogen bond between the enzyme and hydrogen peroxide in the transition state. Here we report two x-ray structures of L29P PFE that support this proposal. Both structures show a main chain carbonyl oxygen closer to the active-site serine as expected. One structure further shows acetate in the active site in an orientation consistent with reaction by an acyl-enzyme mechanism. We also detected an acyl-enzyme intermediate in the hydrolysis of ε-caprolactone by mass spectrometry. Second, can we further increase perhydrolysis activity? We discovered that the reverse reaction – hydrolysis of peracetic acid to acetic acid and hydrogen peroxide – occurs at nearly the diffusion limited rate. Since the reverse reaction cannot increase further, neither can the forward reaction. Consistent with this prediction, two variants with additional amino acid substitutions showed two fold higher kcat, but Km also increased so the specificity constant, kcat/Km, remained similar. Third, how does the L29P substitution change the esterase activity? Ester hydrolysis decreased for most esters (75-fold for ethyl acetate), but not for methyl esters. In contrast, L29P PFE catalyzed hydrolysis of ε-caprolactone five times more efficiently than wild-type PFE. Molecular modeling suggests that moving the carbonyl group closer to the active site blocks access for

Switching Catalysis from Hydrolysis to Perhydrolysis in Pseudomonas fluorescens Esterase

Energy Technology Data Exchange (ETDEWEB)

Yin, D.; Bernhardt, P; Morley, K; Jiang, Y; Cheeseman, J; Purpero, V; Schrag, J; Kazlauskas, R

2010-01-01

Many serine hydrolases catalyze perhydrolysis, the reversible formation of peracids from carboxylic acids and hydrogen peroxide. Recently, we showed that a single amino acid substitution in the alcohol binding pocket, L29P, in Pseudomonas fluorescens (SIK WI) aryl esterase (PFE) increased the specificity constant of PFE for peracetic acid formation >100-fold [Bernhardt et al. (2005) Angew. Chem., Int. Ed. 44, 2742]. In this paper, we extend this work to address the three following questions. First, what is the molecular basis of the increase in perhydrolysis activity? We previously proposed that the L29P substitution creates a hydrogen bond between the enzyme and hydrogen peroxide in the transition state. Here we report two X-ray structures of L29P PFE that support this proposal. Both structures show a main chain carbonyl oxygen closer to the active site serine as expected. One structure further shows acetate in the active site in an orientation consistent with reaction by an acyl-enzyme mechanism. We also detected an acyl-enzyme intermediate in the hydrolysis of {var_epsilon}-caprolactone by mass spectrometry. Second, can we further increase perhydrolysis activity? We discovered that the reverse reaction, hydrolysis of peracetic acid to acetic acid and hydrogen peroxide, occurs at nearly the diffusion limited rate. Since the reverse reaction cannot increase further, neither can the forward reaction. Consistent with this prediction, two variants with additional amino acid substitutions showed 2-fold higher k{sub cat}, but K{sub m} also increased so the specificity constant, k{sub cat}/K{sub m}, remained similar. Third, how does the L29P substitution change the esterase activity? Ester hydrolysis decreased for most esters (75-fold for ethyl acetate) but not for methyl esters. In contrast, L29P PFE catalyzed hydrolysis of {var_epsilon}-caprolactone five times more efficiently than wild-type PFE. Molecular modeling suggests that moving the carbonyl group closer to the

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

Science.gov (United States)

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.

Hydrolysis of cellulose catalyzed by quaternary ammonium perrhenates in 1-allyl-3-methylimidazolium chloride.

Science.gov (United States)

Wang, Jingyun; Zhou, Mingdong; Yuan, Yuguo; Zhang, Quan; Fang, Xiangchen; Zang, Shuliang

2015-12-01

Quaternary ammonium perrhenates were applied as catalyst to promote the hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The quaternary ammonium perrhenates displayed good catalytic performance for cellulose hydrolysis. Water was also proven to be effective to promote cellulose hydrolysis. Accordingly, 97% of total reduced sugar (TRS) and 42% of glucose yields could be obtained under the condition of using 5mol% of tetramethyl ammonium perrhenate as catalyst, 70μL of water, ca. 0.6mmol of microcrystalline cellulose (MCC) and 2.0g of [Amim]Cl as solvent under microwave irradiation for 30min at 150°C (optimal conditions). The influence of quaternary ammonium cation on the efficiency of cellulose hydrolysis was examined based on different cation structures of perrhenates. The mechanism on perrhenate catalyzed cellulose hydrolysis is also discussed, whereas hydrogen bonding between ReO4 anion and hydroxyl groups of cellulose is assumed to be the key step for depolymerization of cellulose. Copyright © 2015. Published by Elsevier Ltd.

Polymeric amylase nanoparticles as a new semi-synthetic enzyme system for hydrolysis of starch.

Science.gov (United States)

Say, R; Şenay, R Hilal; Biçen, Özlem; Ersöz, Arzu; Şişman Yılmaz, Filiz; Akgöl, Sinan; Denizli, Adil

2013-05-01

α-Amylase (EC 3.2.1.1; α-D-1,4,glucan glucanohydrolase) catalyzes the hydrolysis of α-D-(1,4)-glucosidic linkages in starch, glycogen, and various malto-oligosaccharides, by releasing α-anomeric products. In this study, a novel method has been developed to prepare nanoprotein particles that carry α-amylase as a monomer by using a photosensitive microemulsion polymerization process. The nanostructured α-amylase with photosensitive features have been characterized by fluorescence spectroscopy, transmission electron microscopy (TEM) and Zeta Sizer. The fluorescence intensity of amylase nanoparticles was determined to be 658 a.u. at 610 nm and the average particle size of nanoamylase was found to be about 71.8 nm. Both free α-amylase and nanoparticles were used in the hydrolysis of starch under varying reaction conditions such as pH and temperature that affect enzyme activity and the results were compared to each other. Km values were 0.26 and 0.87 mM and Vmax values were 0.36 IU mg(-1) and 22.32 IU mg(-1) for nanoenzyme and free enzyme, respectively. Then, thermal stability, storage stability and reusability were investigated and according to the results, activity was preserved 60% at 60 °C; 20% at 70-80 °C temperature values and 80% after 105 days storage. Finally after 10 cycles, the activity was preserved 90% and this novel enzymatic polymeric amylase nanoparticle has showed considerable potential as reusable catalyst. Copyright © 2012 Elsevier B.V. All rights reserved.

The human digestive tract has proteases capable of gluten hydrolysis

Directory of Open Access Journals (Sweden)

Sergio Gutiérrez

2017-07-01

Conclusion: The digestive tracts of patients with CD and healthy subjects have enzymatic machinery needed for gluten degradation. Patients with CD showed more gluten hydrolysis than did healthy individuals, although, in both cases, a fraction of 33-mer peptide remained intact. Gliadin peptides derived from gastrointestinal digestion, especially the 33-mer, can potentially be used by commensal microbiota from both CD-positive and CD-negative individuals, and differences in bacterial hydrolysis can modify its immunogenic capacity.

Investigation of tributyl phosphate hydrolysis in polymer matrix

International Nuclear Information System (INIS)

Sokal'skaya, L.I.; Yakshin, V.V.; Filippov, E.A.

1978-01-01

Hydrolytic stability of tributyl phosphate to 2 N nitric acid solutions at a temperature of 96 +- 0.5 deg C has been investigated. Tributyl phosphate has been put into a styrene - divinylbenzene matrix. By using the method of potentiometric titration in an anhydrous medium the following has been shown: the quantity of dibutylphosphoric acid that has been formed in the process of hydrolysis of tributylphosphate put into a polymeric matrix is two times smaller than that formed in the process of hydrolysis of pure tributylphosphate under the same conditions. The solubility of tributylphosphate put into a polymer matrix of 240 mg/l in distilled water and of 150 mg/l tributylphosphate in a sodaalkaline solution has been determined

EFFECT OF LIGNIN CONTENT ON ENZYMATIC HYDROLYSIS OF FURFURAL RESIDUES

Directory of Open Access Journals (Sweden)

Jianxin Jiang

2011-02-01

Full Text Available The enzymatic saccharification of pretreated furfural residues with different lignin content was studied to verify the effect of lignin removal in the hydrolysis process. The results showed that the glucose yield was improved by increasing the lignin removal. A maximum glucose yield of 96.8% was obtained when the residue with a lignin removal of 51.4% was hydrolyzed for 108 h at an enzyme loading of 25 FPU/g cellulose. However, further lignin removal did not increase the hydrolysis. The effect of enzyme loading on the enzymatic hydrolysis was also explored in this work. It was concluded that a high glucose yield of 90% was achieved when the enzyme dosage was reduced from 25 to 15 FPU/g cellulose, which was cost-effective for the sugar and ethanol production. The structures of raw material and delignified samples were further characterized by XRD and scanning electron microscopy (SEM.

Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

Directory of Open Access Journals (Sweden)

Rudy Agustriyanto

2012-12-01

Full Text Available Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. The objective of this research is to investigate the production of the glucose through dilute acid pretreatment and to obtain its optimum operating conditions. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast and β-glucosidase (Novozyme 188. The hydrolysis time was 72 hours and the operating conditions were varied at several temperature and pH. From the experimental results it can be concluded that the delignification temperature variation has greater influence than the acid concentration. The optimum operating condition was obtained at pH 4 and 50°C which was pretreated at 100°C using 1.5% acid concentration. Copyright © 2012 by BCREC UNDIP. All rights reserved. (Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 28th September 2012, Revised: 2nd October 2012, Accepted: 4th October 2012[How to Cite: R. Agustriyanto, A. Fatmawati, Y. Liasari. (2012. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 137-141. doi:10.9767/bcrec.7.2.4046.137-141] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4046.137-141 ] | View in 

Process for teating whey by enzymic hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Nocquet, J L

1980-01-01

In the process lactose is converted into glucose and galactose, with demineralization to a level of at least 50%, before the hydrolysis. A bacteriologically stable hydrolysed whey is obtained and may be used in foods for human consumption.

Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

International Nuclear Information System (INIS)

Zhang, Y.; Wu, Q.; Zhang, H.; Zhao, J.

2013-01-01

Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications

Intelligent hydrophilic nanoparticles fabricated via alkaline hydrolysis of crosslinked polyacrylonitrile nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Zhang, Y., E-mail: zhyw@dhu.edu.cn; Wu, Q.; Zhang, H.; Zhao, J. [Donghua University, State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Chemical Fibers Research Institute (China)

2013-07-15

Crosslinked polyacrylonitrile (PAN) nanolatex, with an average hydrodynamic diameter of 84 nm and a polydispersity index of 0.06, was successfully synthesized at a high monomer concentration and low surfactant content via a modified emulsion polymerization. Three measurements were adopted to control the nucleation and growth processes. Taking advantage of the chemical activity of nitrile groups, intelligent hydrophilic polymeric nanoparticles were fabricated via simple alkaline hydrolysis treatment of the crosslinked PAN nanolatex. Dynamic light scattering, electrophoretic light scattering, FT-IR spectroscopy, elemental analysis, and TEM observations were used to monitor the changes in the composition, structure, and morphology of the nanoparticles during the hydrolysis process. The sizes, chemical composition, morphology, and pH-responsive behavior of the intelligent hydrophilic nanoparticles could be adjusted by simply changing the hydrolysis time. As the hydrolysis was prolonged, the following nanoparticles could be obtained, crosslinked PAN nanoparticles with hydrophilic surfaces, amphiphilic nanoparticles with a hydrophobic PAN core and a hydrophilic polymeric shell composed of acrylamide and acrylic acid units, or carboxylic polyacrylamide nanoparticles. These modified nanoparticles all display good hydrophilicity, good biocompatibility, pH-sensitivity, as well as carboxyl functional groups, and thus are ideal candidates for various biomedical applications.

Effects of cocaine on norepinephrine stimulated phosphoinositide hydrolysis and locomotor activity in rat

International Nuclear Information System (INIS)

Mosaddeghi, M.

1989-01-01

The function of α 1 -adrenoceptors was determined by stimulating cortical tissue slices, which were pre-labeled with [ 3 H]inositol, with norepinephrine (NE) in the presence of 8 mM LiCl. Results of in vitro studies showed that cocaine 10 μM potentiated maximal NE-stimulated PI hydrolysis by 30%. In addition, the EC 50 was decreased from 3.93 ± 0.42 to 1.91 ± 0.31 μM NE. Concentrations of 0.1-100 μM and 0.1-10 μM cocaine enhanced PI hydrolysis stimulated by 0.3 and 3 μM NE, respectively. The concentration-effect curves for NE-stimulated PI hydrolysis were shifted to the right 100-fold in the presence of 0.1 μM prazosin. Cocaine (10 μM) did not potentiate NE-stimulated PI hydrolysis in the presence of 0.1 μM prazosin. [ 3 H]Prazosin saturation and NE [ 3 H]prazosin competition binding studies using crude membrane preparations showed that 10 μM cocaine did not alter binding parameters B max , K d , Hill slope, and IC 50 . Together, these results implied that cocaine in vitro potentiated NE-stimulated PI hydrolysis by blocking NE reuptake. For in vivo studies, the locomotor activity was determined after an acute or chronic injections of either cocaine or saline. Cocaine or saline-treated rats were killed after measurement of the locomotor activity, and NE-stimulated PI hydrolysis was measured. Acute administration of cocaine 3.2-42 mg/kg (i.p.) produced an inverted U shaped dose-response curve on locomotor activity. The peak increase in locomotor activity was at 32 mg/kg cocaine. A dose of 42 mg/kg cocaine produced a significant depression of maximal NE-stimulated PI hydrolysis

The europium and praseodymium hydrolysis in a 2M NaCl environment

International Nuclear Information System (INIS)

Jimenez R, M.; Lopez G, H.; Solache R, M.; Rojas H, A.

1998-01-01

It was studied the europium and praseodymium hydrolysis in a 2M NaCl ion force environment at 303 K, through two methods: this one extraction with dissolvents (lanthanide-water-NaCl-dibenzoylmethane) in presence of a competitive ligand (diglycolic acid) and that one direct potentiometric titration, of soluble species, followed by a computer refining. The values of one or another techniques of the first hydrolysis constants obtained were similar, which demonstrates that the results are reliable. The set of data obtained on the stability constants of hydrolysis products allowed to draw up the distribution diagrams of chemical species, as europium as praseodymium in aqueous environment. (Author)

A study on the phase transformation of the nanosized hydroxyapatite synthesized by hydrolysis using in situ high temperature X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Shih, W.-J. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan, 70101, Taiwan (China); Wang, J.-W. [Department of Enviromental and Safety Engineering, Chung Hwa College of Medical Technology, 89 Wen-Hua 1st St., Rende Shiang, Tainan, 71703, Taiwan (China); Wang, M.-C. [Department of Materials Science and Engineering, National United University, 1 Lien-Da, Kung-Ching Li, Miao Li 360, Taiwan (China)]. E-mail: mcwang@nuu.edu.tw; Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan, 70101, Taiwan (China); Dayeh University, 112 Shan-Jiau Road, Da-Tsuen, Changhua 515, Taiwan (China)

2006-09-15

The biodegradable hydroxyapatite (HA) was synthesized by hydrolysis and characterized using high temperature X-ray diffraction (HT-XRD), differential thermal analysis and thermogravimetry (DTA/TG), and scanning electron microscopy (SEM). The in situ phase transformation of the HA synthesized from CaHPO{sub 4}.2H{sub 2}O (DCPD) and CaCO{sub 3} with a Ca / P = 1.5 in 2.5 M NaOH{sub (aq)} at 75 deg. C for 1 h was investigated by HT-XRD between 25 and 1500 deg. C. The HA was crystallized at 600 deg. C and maintained as the major phase until 1400 deg. C. The HA steadily transformed to the {alpha}-tricalcium phosphate ({alpha}-TCP) which became the major phosphate phase at 1500 deg. C. At 700 deg. C, the minor CaO phase appeared and vanished at 1300 deg. C. The Na{sup +} impurity from the hydrolysis process was responsible for the formation of the NaCaPO{sub 4} phase, which appeared above 800 deg. C and disappeared at 1200 deg. C.

Correlation between sensitivity to acid hydrolysis and skin-core differentiation in viscose rayon

NARCIS (Netherlands)

Hermans, P.H.; Heikens, D.

1952-01-01

It is shown that the extent of hydrolysis in a given set of conditions is qualitatively related to the thickness of the rayon skin. This interpretation is preferable to that of relating extent of hydrolysis to crystalline amorphous ratio.

Stochastic simulation of thermally assisted magnetization reversal in sub-100 nm dots with perpendicular anisotropy

International Nuclear Information System (INIS)

Purnama, Budi; Koga, Masashi; Nozaki, Yukio; Matsuyama, Kimihide

2009-01-01

Thermally assisted magnetization reversal of sub-100 nm dots with perpendicular anisotropy has been investigated using a micromagnetic Langevin model. The performance of the two different reversal modes of (i) a reduced barrier writing scheme and (ii) a Curie point writing scheme are compared. For the reduced barrier writing scheme, the switching field H swt decreases with an increase in writing temperature but is still larger than that of the Curie point writing scheme. For the Curie point writing scheme, the required threshold field H th , evaluated from 50 simulation results, saturates at a value, which is not simply related to the energy barrier height. The value of H th increases with a decrease in cooling time owing to the dynamic aspects of the magnetic ordering process. Dependence of H th on material parameters and dot sizes has been systematically studied

Increased release of fermentable sugars from elephant grass by enzymatic hydrolysis in the presence of surfactants

International Nuclear Information System (INIS)

Menegol, Daiane; Scholl, Angélica Luisi; Fontana, Roselei Claudete; Dillon, Aldo José Pinheiro; Camassola, Marli

2014-01-01

Highlights: • Milling is an attractive method to enhance the enzymatic hydrolysis of biomass. • Surfactants improve the efficiency of lignocellulose enzymatic hydrolysis. • Pretreatment with NaOH, smaller particle size and Tween 80® were more efficient. - Abstract: In the search for renewable energy sources, elephant grass is an alternative substrate for ethanol production, but this substrate must be hydrolyzed by cellulases and xylanases to liberate fermentable sugars. During enzymatic hydrolysis, cellulase activity is reduced by the irreversible adsorption of cellulase onto cellulose, decreasing the rate of hydrolysis. Adding surfactants during hydrolysis can improve the process. The effects of Tween® and Triton® surfactants on the enzymatic hydrolysis of elephant grass were evaluated in this context. The data indicate that pretreatment with sodium hydroxide, along with a smaller particle size (0.075–0.152 mm) and the use of Tween 80®, increased the efficiency of releasing reducing sugars from pretreated elephant grass biomass. Thus, it is possible to reduce grinding costs in second-generation ethanol production through the use of surfactants, as they allow efficient hydrolysis of larger biomass particles

Evaluation of wet oxidation pretreatment for enzymatic hydrolysis of softwood

DEFF Research Database (Denmark)

Palonen, H.; Thomsen, A.B.; Tenkanen, M.

2004-01-01

The wet oxidation pretreatment (water, oxygen, elevated temperature, and pressure) of softwood (Picea abies) was investigated for enhancing enzymatic hydrolysis. The pretreatment was preliminarily optimized. Six different combinations of reaction time, temperature, and pH were applied......, and the compositions of solid and liquid fractions were analyzed. The solid fraction after wet oxidation contained 58-64% cellulose, 2-16% hemicellulose, and 24-30% lignin. The pretreatment series gave information about the roles of lignin and hemicellulose in the enzymatic hydrolysis. The temperature...

DEXTRINIZED SYRUPS OBTAINING THROUGH THE ENZYMATIC HYDROLYSIS OF SORGHUM STARCH

Directory of Open Access Journals (Sweden)

Leyanis Rodríguez Rodríguez

2015-10-01

Full Text Available The main objective of this work was the production of syrups dextrinized by enzymatic hydrolysis of starch red sorghum CIAPR-132 using α-amylase on solutions at different concentrations, with different concentrations of enzyme and enzyme hydrolysis time. The response variable was the dextrose equivalent in each obtained syrup (ED using the modified Lane-Eynon method. In some of the experiments, we used a full factorial design 23 and in others we worked with intermediate concentration and higher hydrolysis time with different levels of enzyme. The obtained products were syrups dextrinized ED between 10,25 and 33,97% (values we can find within the established ones for these types of syrups, which can be used for their functional properties as intermediates syrups or as raw material for different processes of the food industry. This allows you to set a pattern for the use of sorghum feedstock in unconventional obtaining products from its starch.

In situ observation of lithium hydride hydrolysis by DRIFT spectroscopy

International Nuclear Information System (INIS)

Awbery, Roy P.; Broughton, Duncan A.; Tsang, S.C.

2008-01-01

Polycrystalline LiH was studied in situ using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy to investigate the effect water vapour has on the rate of production of the corrosion products, particularly LiOH. The reaction rate of the formation of surface LiOH was monitored by measurement of the hydroxyl (OH) band at 3676 cm -1 . The initial hydrolysis rate of LiH exposed to water vapour at 50% relative humidity was found to be almost two times faster than LiH exposed to water vapour at 2% relative humidity. The hydrolysis rate was shown to be initially very rapid followed by a much slower, almost linear rate. The change in hydrolysis rate was attributed to the formation of a coherent layer of LiOH on the LiH surface. Exposure to lower levels of water vapour appeared to result in the formation of a more coherent corrosion product, resulting in effective passivation of the surface to further attack from water

Hydrolysis of fish protein by Bacillus megaterium cells immobilized in radiation induced polymerized wood

International Nuclear Information System (INIS)

Ghosh, S.; Alur, M.D.; Nerkar, D.P.

1992-01-01

The immobilization of Bacillus megaterium cells in radiation-induced polymerized wood was studied for hydrolysis of trash fish protein. The optimum conditions and reaction kinetics for hydrolysis of protein by free and immobilized cells were found to be similar. Maximum hydrolysis occurred at 50 o C and at pH 7.5 with 15-20% (w/v) of immobilized matrix. The soluble content of the resultant hydrolysate about 2.4% (w/v). (author). 10 refs., 4 figs

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

Science.gov (United States)

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

Assessing Reliability of Cellulose Hydrolysis Models to Support Biofuel Process Design – Identifiability and Uncertainty Analysis

DEFF Research Database (Denmark)

Sin, Gürkan; Meyer, Anne S.; Gernaey, Krist

2010-01-01

The reliability of cellulose hydrolysis models is studied using the NREL model. An identifiability analysis revealed that only 6 out of 26 parameters are identifiable from the available data (typical hydrolysis experiments). Attempting to identify a higher number of parameters (as done in the ori......The reliability of cellulose hydrolysis models is studied using the NREL model. An identifiability analysis revealed that only 6 out of 26 parameters are identifiable from the available data (typical hydrolysis experiments). Attempting to identify a higher number of parameters (as done...

Modeling enzymatic hydrolysis of lignocellulosic substrates using confocal fluorescence microscopy I: filter paper cellulose.

Science.gov (United States)

Luterbacher, Jeremy S; Moran-Mirabal, Jose M; Burkholder, Eric W; Walker, Larry P

2015-01-01

Enzymatic hydrolysis is one of the critical steps in depolymerizing lignocellulosic biomass into fermentable sugars for further upgrading into fuels and/or chemicals. However, many studies still rely on empirical trends to optimize enzymatic reactions. An improved understanding of enzymatic hydrolysis could allow research efforts to follow a rational design guided by an appropriate theoretical framework. In this study, we present a method to image cellulosic substrates with complex three-dimensional structure, such as filter paper, undergoing hydrolysis under conditions relevant to industrial saccharification processes (i.e., temperature of 50°C, using commercial cellulolytic cocktails). Fluorescence intensities resulting from confocal images were used to estimate parameters for a diffusion and reaction model. Furthermore, the observation of a relatively constant bound enzyme fluorescence signal throughout hydrolysis supported our modeling assumption regarding the structure of biomass during hydrolysis. The observed behavior suggests that pore evolution can be modeled as widening of infinitely long slits. The resulting model accurately predicts the concentrations of soluble carbohydrates obtained from independent saccharification experiments conducted in bulk, demonstrating its relevance to biomass conversion work. © 2014 Wiley Periodicals, Inc.

Hydrolysis of solubilized hemicellulose derived from wet-oxidized wheat straw by a mixture of commercial fungal enzyme preparations

Energy Technology Data Exchange (ETDEWEB)

Skammelsen Schmidt, Anette; Thomsen, Alle Belinda; Woidemann, Anders [Risoe National Lab. (Denmark); Tenkanen, Maija [VTT Biotechnology and Food Research (Finland)

1998-04-01

The enzymatic hydrolysis of the solubilized hemicellulose fraction from wet-oxidized wheat straw was investigated for quantification purposes. An optimal hydrolysis depends on factors such as composition of the applied enzyme mixture and the hydrolysis conditions (enzyme loading, hydrolysis time, pH-value, and temperature). A concentrated enzyme mixture was used in this study prepared at VTT Biotechnology and Food Research, Finland, by mixing four commercial enzyme preparations. No distinctive pH-value and temperature optima were identified after a prolonged incubation of 24 hours. By reducing the hydrolysis time to 2 hours a temperature optimum was found at 50 deg. C, where a pH-value higher than 5.2 resulted in reduced activity. An enzyme-substrate-volume-ratio of 0.042, a pH-value of 5.0, and a temperature of 50 deg. C were chosen as the best hydrolysis conditions due to an improved monosaccharide yield. The hydrolysis time was chosen to be 24 hours to ensure equilibrium and total quantification. Even under the best hydrolysis conditions, the overall sugar yield from the enzymatic hydrolysis was only 85% of that of the optimal acid hydrolysis. The glucose yield were approximately the same for the two types of hydrolyses, probably due to the high cellulase activity in the VTT-enzyme mixture. For xylose and arabinose the enzymatic hydrolysis yielded only 80% of that of the acid hydrolysis. As the pentoses existed mainly as complex polymers their degradation required many different enzymes, some of which might be missing from the VTT-enzyme mixture. Furthermore, the removal of side-choins from the xylan backbone during the wet-oxidation pretreatment process might enable the hemicellulosic polymers to interact and precipitate, hence, reducing the enzymatic digestibility of the hemicellulose. (au) 8 tabs., 10 ills., 65 refs.

Sodium borohydride hydrolysis in the presence of intermetallic compound LaNi5

International Nuclear Information System (INIS)

Korobov, I.I.; Mozgina, N.G.

1992-01-01

Kinetics of catalytic hydrolysis of sodium borohydride in the 1 mol/l solution of caustic sodium within the range of 298-318 K in presence of LaNi 5 intermetallic compound is studied. It is established that the reaction has zero order by NaBH 4 and the first one by LaNi 5 . The apparent activation energy of NaBH 4 catalytic hydrolysis in presence of LaNi 5 , calculated on the basis of temperature dependence of reaction velocity, is constant within the temperature range under investigation and constitutes 56$+-$1.5 kJ/mol. Recombination of surface hydrogen on LaNi 5 in molecular one is limiting stage determining NaBH 4 hydrolysis rate

Nanoscale thermal transport. II. 2003–2012

OpenAIRE

Cahill, David G.; Braun, Paul V.; Chen, Gang; Clarke, David R.; Fan, Shanhui; Goodson, Kenneth E.; Keblinski, Pawel; King, William P.; Mahan, Gerald D.; Majumdar, Arun; Maris, Humphrey J.; Phillpot, Simon R.; Pop, Eric; Shi, Li

2013-01-01

A diverse spectrum of technology drivers such as improved thermal barriers, higher efficiency thermoelectric energy conversion, phase-change memory, heat-assisted magnetic recording, thermal management of nanoscale electronics, and nanoparticles for thermal medical therapies are motivating studies of the applied physics of thermal transport at the nanoscale. This review emphasizes developments in experiment, theory, and computation in the past ten years and summarizes the present status of th...

Significant thermal energy reduction in lactic acid production process

International Nuclear Information System (INIS)

Mujtaba, Iqbal M.; Edreder, Elmahboub A.; Emtir, Mansour

2012-01-01

Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 ; Mujtaba and Macchietto, 1997 ). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation () processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.

High-Quality Large-Magnification Polymer Lens from Needle Moving Technique and Thermal Assisted Moldless Fabrication Process.

Directory of Open Access Journals (Sweden)

Ratthasart Amarit

Full Text Available The need of mobile microscope is escalating as well as the demand of high quality optical components in low price. We report here a novel needle moving technique to fabricate milli-size lens together with thermal assist moldless method. Our proposed protocol is able to create a high tensile strength structure of the lens and its base which is beneficial for exploiting in convertinga smart phone to be a digital microscope. We observe that no bubble trapped in a lens when this technique is performed which can overcome a challenge problem found in a typical dropping technique. We demonstrate the symmetry, smoothness and micron-scale resolution of the fabricated structure. This proposed technique is promising to serve as high quality control mass production without any expensive equipment required.

Point mutation in FGF receptor eliminates phosphatidylinositol hydrolysis without affecting mitogenesis.

Science.gov (United States)

Mohammadi, M; Dionne, C A; Li, W; Li, N; Spivak, T; Honegger, A M; Jaye, M; Schlessinger, J

1992-08-20

Stimulation of growth factor receptors with tyrosine kinase activity is followed by rapid receptor dimerization, tyrosine autophosphorylation and phosphorylation of signalling molecules such as phospholipase C gamma (PLC gamma) and the ras GTPase-activating protein. PLC gamma and GTPase-activating protein bind to specific tyrosine-phosphorylated regions in growth factor receptors through their src-homologous SH2 domains. Growth factor-induced tyrosine phosphorylation of PLC gamma is essential for stimulation of phosphatidylinositol hydrolysis in vitro and in vivo. We have shown that a short phosphorylated peptide containing tyrosine at position 766 from a conserved region of the fibroblast growth factor (FGF) receptor is a binding site for the SH2 domain of PLC gamma (ref. 8). Here we show that an FGF receptor point mutant in which Tyr 766 is replaced by a phenylalanine residue (Y766F) is unable to associate with and tyrosine-phosphorylate PLC gamma or to stimulate hydrolysis of phosphatidylinositol. Nevertheless, the Y766F FGF receptor mutant can be autophosphorylated, and can phosphorylate several cellular proteins and stimulate DNA synthesis. Our data show that phosphorylation of the conserved Tyr 766 of the FGF receptor is essential for phosphorylation of PLC gamma and for hydrolysis of phosphatidylinositol, but that elimination of this hydrolysis does not affect FGF-induced mitogenesis.

A DFT-based comparative equilibrium study of thermal dehydration and hydrolysis of CaCl2 hydrates and MgCl2 hydrates for seasonal heat storage

NARCIS (Netherlands)

Pathak, A.D.; Gaastra-Nedea, S.V.; Zondag, H.A.; Rindt, C.C.M.; Smeulders, D.M.J.

2016-01-01

Salt hydrates store solar energy in chemical form via a reversible dehydration–hydration reaction. However, as a side reaction to dehydration, hydrolysis (HCl formation) may occur in chloride based salt hydrates (specially in MgCl2 hydrates), affecting the durability of the storage system. The

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

Energy Technology Data Exchange (ETDEWEB)

Agu, R.C.; Amadife, A.E.; Ude, C.M.; Onyia, A.; Ogu, E.O. [Enugu State Univ. of Science and Technology (Nigeria). Faculty of Applied Natural Sciences; Okafor, M.; Ezejiofor, E. [Nnamdi Azikiwe Univ., Awka (Nigeria). Dept. of Applied Microbiology

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.

Characteristic Studies of Micron Zinc Particle Hydrolysis in a Fixed Bed Reactor

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Lv Ming

2015-09-01

Full Text Available Zinc fuel is considered as a kind of promising energy sources for marine propeller. As one of the key steps for zinc marine energy power system, zinc hydrolysis process had been studied experimentally in a fixed bed reactor. In this study, we focus on the characteristics of micron zinc particle hydrolysis. The experimental results suggested that the steam inner diffusion is the controlling step of accumulative zinc particles hydrolysis reaction at a relative lower temperature and a relative higher water partial pressure. In other conditions, the chemical reaction kinetics was the controlling step. And two kinds of chemical reaction kinetics appeared in experiments: the surface reaction and the gas-gas reaction. The latter one occurs usually for larger zinc particles and high reaction temperature. Temperature seems to be one of the most important parameters for the dividing of different reaction mechanisms. Several parameters of the hydrolysis process including heating rate, water partial pressure, the particle size and temperature were also studied in this paper. Results show that the initial reaction temperature of zinc hydrolysis in fixed bed is about 410°C. And the initial reaction temperature increases as the heating rate increases and as the water partial pressure decreases. The total hydrogen yield increases as the heating rate decreases, as the water partial pressure increases, as the zinc particle size decreases, and as the reaction temperature increases. A hydrogen yield of more than 81.5% was obtained in the fixed bed experiments.

Kinetic study of enzymatic hydrolysis of acid-pretreated coconut coir

Science.gov (United States)

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.

A first step towards identification of tannin-derived black carbon: Conventional pyrolysis (Py–GC–MS) and thermally assisted hydrolysis and methylation (THM–GC–MS) of charred condensed tannins

NARCIS (Netherlands)

Kaal, J.; Nierop, K.G.J.; Kraal, P.; Preston, C.M.

2012-01-01

Tannins account for a significant proportion of plant biomass and are likely to contribute to the residues formed by incomplete biomass combustion (black carbon, BC). Nonetheless, the molecular properties of thermally modified tannins have not been investigated in laboratory charring experiments. We

Lignin-based polyoxyethylene ether enhanced enzymatic hydrolysis of lignocelluloses by dispersing cellulase aggregates.

Science.gov (United States)

Lin, Xuliang; Qiu, Xueqing; Yuan, Long; Li, Zihao; Lou, Hongming; Zhou, Mingsong; Yang, Dongjie

2015-06-01

Water-soluble lignin-based polyoxyethylene ether (EHL-PEG), prepared from enzymatic hydrolysis lignin (EHL) and polyethylene glycol (PEG1000), was used to improve enzymatic hydrolysis efficiency of corn stover. The glucose yield of corn stover at 72h was increased from 16.7% to 70.1% by EHL-PEG, while increase in yield with PEG4600 alone was 52.3%. With the increase of lignin content, EHL-PEG improved enzymatic hydrolysis of microcrystalline cellulose more obvious than PEG4600. EHL-PEG could reduce at least 88% of the adsorption of cellulase on the lignin film measured by quartz crystal microbalance with dissipation monitoring (QCM-D), while reduction with PEG4600 was 43%. Cellulase aggregated at 1220nm in acetate buffer analyzed by dynamic light scattering. EHL-PEG dispersed cellulase aggregates and formed smaller aggregates with cellulase, thereby, reduced significantly nonproductive adsorption of cellulase on lignin and enhanced enzymatic hydrolysis of lignocelluloses. Copyright © 2015 Elsevier Ltd. All rights reserved.

ENZYMATIC HYDROLYSIS OF SWITCHGRASS AND COASTAL BERMUDA GRASS PRETREATED USING DIFFERENT CHEMICAL METHODS

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Jiele Xu

2011-06-01

Full Text Available To investigate the effects of biomass feedstock and pretreatment method on the enzyme requirement during hydrolysis, swichgrass and coastal Bermuda grass pretreated using H2SO4, NaOH, and Ca(OH2 at the optimal conditions were subjected to enzymatic hydrolysis using two enzyme combinations: NS 50013 + NS 50010 and Cellic CTec + Cellic HTec. The enzyme loadings were optimized, and correlations between feedstock property, pretreatment strategy, and enzyme usage were evaluated. The results show that pretreatment methods resulting in greater lignin contents in the pretreated biomass were generally associated with higher enzyme requirements. More sugars could be recovered from alkaline-pretreated biomass during enzymatic hydrolysis due to the better carbohydrate preservation achieved at mild pretreatment temperatures. The cellulase enzyme, Cellic CTec, was more efficient in catalyzing the hydrolysis of coastal Bermuda grass, a feedstock more digestible than the pretreated swichgrass, following pretreatment with NaOH or Ca(OH2.

Low temperature alkaline pH hydrolysis of oxygen-free Titan tholins

Science.gov (United States)

Brassé, Coralie; Buch, Arnaud; Raulin, François; Coll, Patrice; Poch, Olivier; Ramirez, Sandra

2014-05-01

The largest moon of Saturn, Titan, is known for its dense, nitrogen-rich atmosphere. The organic aerosols which are produced in Titan's atmosphere are of great astrobiological interest, particularly because of their potential evolution when they reach the surface and may interact with putative ammonia-water cryomagma[1]. In this context we have followed the evolution of alkaline pH hydrolysis (25wt% ammonia-water) of Titan tholins (produced by an experimental setup using a plasma DC discharge named PLASMA) at low temperature. Urea has been identified as one of the main product of tholins hydrolysis along with several amino acids (alanine, glycine and aspartic acid). However, those molecules have also been detected in non-hydrolyzed tholins. One explanation is a possible oxygen leak in the PLASMA reactor during the tholins synthesis[2]. Following this preliminary study the synthesis protocol has been improved by isolating the whole device in a specially designed glove box which protect the PLASMA experiment from the laboratory atmosphere. Once we confirmed the non-presence of oxygen in tholins, we performed alkaline pH hydrolysis of oxygen-free tholins. Then we verify that the organic compounds cited above are still produced in-situ. Moreover, a recent study shows that the subsurface ocean may contain a lower fraction of ammonia (about 5wt% or less[3]), than the one used until now in this kind of experimental study[2, 4]. Thus, we have carried out new hydrolysis experiments which take this lower value into account. Additional studies have provided new highlights on the bulk composition of Titan for various gas species. Indeed, the observed Saturn's atmosphere enrichment constrains the composition of the planetesimals present in the feeding zone of Saturn. The enrichment in volatiles in Saturn's atmosphere has been reproduced by assuming the presence of specific gas species[5, 6], in particular CO2 and H2S. In the present study we assume that those gas species have

Solar thermal utilization--an overview

International Nuclear Information System (INIS)

Chen Deming; Xu Gang

2007-01-01

Solar energy is an ideal renewable energy source and its thermal utilization is one of its most important applications. We review the status of solar thermal utilization, including: (1) developed technologies which are already widely used all over the world, such as solar assisted water heaters, solar cookers, solar heated buildings and so on; (2) advanced technologies which are still in the development or laboratory stage and could have more innovative applications, including thermal power generation, refrigeration, hydrogen production, desalination, and chimneys; (3) major problems which need to be resolved for advanced utilizaiton of solar thermal energy. (authors)

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

International Nuclear Information System (INIS)

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

1985-01-01

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

Characterization of β-glucosidase from Aspergillus terreus and its application in the hydrolysis of soybean isoflavones* #

Science.gov (United States)

Yan, Feng-ying; Xia, Wei; Zhang, Xiao-xu; Chen, Sha; Nie, Xin-zheng; Qian, Li-chun

2016-01-01

An extracellular β-glucosidase produced by Aspergillus terreus was identified, purified, characterized and was tested for the hydrolysis of soybean isoflavone. Matrix-assisted laser desorption/ionization with tandem time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) revealed the protein to be a member of the glycosyl hydrolase family 3 with an apparent molecular mass of about 120 kDa. The purified β-glucosidase showed optimal activity at pH 5.0 and 65 °C and was very stable at 50 °C. Moreover, the enzyme exhibited good stability over pH 3.0–8.0 and possessed high tolerance towards pepsin and trypsin. The kinetic parameters K m (apparent Michaelis-Menten constant) and V max (maximal reaction velocity) for p-nitrophenyl-β-D-glucopyranoside (pNPG) were 1.73 mmol/L and 42.37 U/mg, respectively. The K m and V max for cellobiose were 4.11 mmol/L and 5.7 U/mg, respectively. The enzyme efficiently converted isoflavone glycosides to aglycones, with a hydrolysis rate of 95.8% for daidzin, 86.7% for genistin, and 72.1% for glycitin. Meanwhile, the productivities were 1.14 mmol/(L·h) for daidzein, 0.72 mmol/(L·h) for genistein, and 0.19 mmol/(L·h) for glycitein. This is the first report on the application of A. terreus β-glucosidase for converting isoflavone glycosides to their aglycones in soybean products. PMID:27256679

Characterization of β-glucosidase from Aspergillus terreus and its application in the hydrolysis of soybean isoflavones.

Science.gov (United States)

Yan, Feng-Ying; Xia, Wei; Zhang, Xiao-Xu; Chen, Sha; Nie, Xin-Zheng; Qian, Li-Chun

2016-06-01

An extracellular β-glucosidase produced by Aspergillus terreus was identified, purified, characterized and was tested for the hydrolysis of soybean isoflavone. Matrix-assisted laser desorption/ionization with tandem time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) revealed the protein to be a member of the glycosyl hydrolase family 3 with an apparent molecular mass of about 120 kDa. The purified β-glucosidase showed optimal activity at pH 5.0 and 65 °C and was very stable at 50 °C. Moreover, the enzyme exhibited good stability over pH 3.0-8.0 and possessed high tolerance towards pepsin and trypsin. The kinetic parameters Km (apparent Michaelis-Menten constant) and Vmax (maximal reaction velocity) for p-nitrophenyl-β-D-glucopyranoside (pNPG) were 1.73 mmol/L and 42.37 U/mg, respectively. The Km and Vmax for cellobiose were 4.11 mmol/L and 5.7 U/mg, respectively. The enzyme efficiently converted isoflavone glycosides to aglycones, with a hydrolysis rate of 95.8% for daidzin, 86.7% for genistin, and 72.1% for glycitin. Meanwhile, the productivities were 1.14 mmol/(L·h) for daidzein, 0.72 mmol/(L·h) for genistein, and 0.19 mmol/(L·h) for glycitein. This is the first report on the application of A. terreus β-glucosidase for converting isoflavone glycosides to their aglycones in soybean products.

Kinetics of glycoalkaloid hydrolysis and solanidine extraction in liquid-liquid systems

Directory of Open Access Journals (Sweden)

Stanković Mihajlo Z.

2002-01-01

Full Text Available The kinetics of glycoalkaloid hydrolysis and solanidine extraction in Analyzed in this study. obtained from dried and milled potato haulm to to which hydrochlotic acid was added is the first liquid phase, while chloroform trichloroethylene or carbon tetrachlondeisthe second organic, liquid phase. The purpose of this paper was to combine the processes of glycoalkaloid hydrolysis to solanidine and solanidine extraction into one step, and to find the optimal liquid-liquid system for such a process.

On the Brønsted acid-catalyzed homogeneous hydrolysis of furans.

Science.gov (United States)

Nikbin, Nima; Caratzoulas, Stavros; Vlachos, Dionisios G

2013-11-01

Furan affairs: Electronic structure calculations of the homogeneous Brønsted acid-catalyzed hydrolysis of 2,5-dimethylfuran show that proton transfer to the β-position is rate-limiting and provides support that the hydrolysis follows general acid catalysis. By means of projected Fukui indices, we show this to be the case for unsubstituted, 2-, and 2,5-substituted furans with electron-donating groups. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Variation of structures of ingredients of desiccated coconut during hydrolysis by hydrochloric acid at low temperature

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Jian XIONG

2017-10-01

Full Text Available Abstract Owing to the high content of lignocellulose, desiccated coconut become a healthy material for dietary fiber supplementation. In this study, the changes in solubility of the fibers of desiccated coconut were evaluated. The changes of the pHs and weight losses were studied. Furthermore, variations of the ingredient structures of desiccated coconut by hydrolysis by hydrochloric acid were characterized by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD and scanning electron microscopy (SEM. After hydrolysis 30 s, the pHs of all systems increased, while six hours later, the pH of only system with initial pH = 1.00 decreased. The decline of pH only existed in hydrolysis systems with initial pH = 1.00, there is no relevant with the quantities of desiccated coconut. The lower initial pH of hydrolysis system was, the less the intrinsic viscosity of the desiccated coconut after hydrolysis was, the small the crystallinity was. After hydrolysis, the microstructure of the desiccated coconut become looser, and the secondary structure of the coconut protein became more stable and ordered. The results suggest that the hydrolysis of desiccated coconut mainly occurred in the branched chain and the non-crystalline region of lignocellulose, which transforms some insoluble dietary fiber into soluble dietary fiber. This improves the nutritional value of desiccated coconut.

Secondary deuterium isotope effects for acid-catalyzed hydrolysis of inosine and adenosine

International Nuclear Information System (INIS)

Romero, R.; Stein, R.; Bull, H.G.; Cordes, E.H.

1978-01-01

Kinetic α deuterium isotope effects have been measured for acid-catalyzed hydrolysis of inosine and adenosine. For inosine hydrolysis, values of k/sub H/k/sub D/ follow: in 1.0 M HCl, 1.21 and 1.20 at 25 and 50 0 C, respectively; in 0.1 M HCl, 1.19 and 1.18 at 25 and 50 0 C, respectively. For adenosine hydrolysis, k/sub H/k/sub D/ is 1.23 in 0.1 M HCl at 25 0 C. The values require that the transition states for hydrolysis of both the monocation and dication of inosine and the dication of adenosine have marked oxocarbonium ion character. Detailed mechanisms which accord with this and other experimental observations include (1) a classical Al mechanism in which the C--N bond is largely cleaved in the transition state; (2) a mechanism involving some form of nucleophilic participation by solvent in which bond cleavage is advanced relative to bond formation in the transition state; or (3) complete C--N bond cleavage with rate-determining diffusion apart of oxocarbonium ion and purine base. 53 references, 1 figure, 2 tables

Simultaneous hydrolysis and hydrogenation of cellobiose to sorbitol in molten salt hydrate media

NARCIS (Netherlands)

Li, J.; Soares, H.S.M.P.; Moulijn, J.A.; Makkee, M.

2013-01-01

The hydrolysis and hydrogenation of cellobiose (4-O-b-D-glucopyranosyl-D-glucose) in ZnCl2_4H2O solvent was studied to optimize the conditions for conversion of lignocellulose (the most abundant renewable resource) into sorbitol (D-glucitol). Water at neutral pH does not allow hydrolysis of

Lipid hydrolysis products affect the composition of infant gut microbial communities in vitro

DEFF Research Database (Denmark)

Bennike, Rikke Mette Guldhammer; Bahl, Martin Iain; Vigsnæs, Louise Kristine

2015-01-01

to 14 : 0 and MAG 12 : 0) or long-chained NEFA (LC-NEFA; 16 : 0 to 18 : 1 and MAG 16 : 0) with and without sphingosine, representing lipid hydrolysis products characteristic for intestinal hydrolysis of breast milk lipids. Ion Torrent sequencing of the bacterial 16S ribosomal RNA gene revealed...

Effects of copper source and concentration on in vitro phytate phosphorus hydrolysis by phytase.

Science.gov (United States)

Pang, Yanfang; Applegate, Todd J

2006-03-08

Five copper (Cu) sources were studied at pH 2.5, 5.5, and 6.5 to determine how Cu affects phytate phosphorus (PP) hydrolysis by phytase at concentrations up to 500 mg/kg diet (60 min, 40-41 degrees C). Subsequently, Cu solubility with and without sodium phytate was measured. Adding Cu inhibited PP hydrolysis at pH 5.5 and pH 6.5 (P copper chloride and copper lysinate inhibited PP hydrolysis much less than copper sulfate pentahydrate, copper chloride, and copper citrate (P copper-phytin complexes.

Modelling ethanol production from cellulose: separate hydrolysis and fermentation versus simultaneous saccharification and fermentation

NARCIS (Netherlands)

Drissen, R.E.T.; Maas, R.H.W.; Tramper, J.; Beeftink, H.H.

2009-01-01

In ethanol production from cellulose, enzymatic hydrolysis, and fermentative conversion may be performed sequentially (separate hydrolysis and fermentation, SHF) or in a single reaction vessel (simultaneous saccharification and fermentation, SSF). Opting for either is essentially a trade-off between

Combined subcritical water and enzymatic hydrolysis for reducing sugar production from coconut husk

Science.gov (United States)

Muharja, Maktum; Junianti, Fitri; Nurtono, Tantular; Widjaja, Arief

2017-05-01

Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinose glucose, galactose, mannose) was 1.254 gr per 6 gr raw material, representing 53.95% of total sugar in coconut husk biomass which was obtained at 150°C 80 bar for 60 minutes reaction time of SCW-treated and 6 hour of enzymatic hydrolysis using mixture of pure cellulose and xylanase enzymes (18.6 U /gram of coconut husk).

Potentiometric determination of the 'formal' hydrolysis ratio of aluminium species in aqueous solutions

International Nuclear Information System (INIS)

Fournier, Agathe C.; Shafran, Kirill L.; Perry, Carole C.

2008-01-01

The 'formal' hydrolysis ratio (h = C(OH - ) added /C(Al) total ) of hydrolysed aluminium-ions is an important parameter required for the exhaustive and quantitative speciation-fractionation of aluminium in aqueous solutions. This paper describes a potentiometric method for determination of the formal hydrolysis ratio based on an automated alkaline titration procedure. The method uses the point of precipitation of aluminium hydroxide as a reference (h = 3.0) in order to calculate the initial formal hydrolysis ratio of hydrolysed aluminium-ion solutions. Several solutions of pure hydrolytic species including aluminium monomers (AlCl 3 ), Al 13 polynuclear cluster ([Al 13 O 4 (OH) 24 (H 2 O) 12 ] 7+ ), Al 30 polynuclear cluster ([Al 30 O 8 (OH) 56 (H 2 O) 26 ] 18+ ) and a suspension of nanoparticulate aluminium hydroxide have been used as 'reference standards' to validate the proposed potentiometric method. Other important variables in the potentiometric determination of the hydrolysis ratio have also been optimised including the concentration of aluminium and the type and strength of alkali (Trizma-base, NH 3 , NaHCO 3 , Na 2 CO 3 and KOH). The results of the potentiometric analysis have been cross-verified by quantitative 27 Al solution nuclear magnetic resonance ( 27 Al NMR) measurements. The 'formal' hydrolysis ratio of a commercial basic aluminium chloride has been measured as an example of a practical application of the developed technique

Visualizing phosphodiester-bond hydrolysis by an endonuclease

DEFF Research Database (Denmark)

Molina, Rafael; Stella, Stefano; Redondo, Pilar

2015-01-01

The enzymatic hydrolysis of DNA phosphodiester bonds has been widely studied, but the chemical reaction has not yet been observed. Here we follow the generation of a DNA double-strand break (DSB) by the Desulfurococcus mobilis homing endonuclease I-DmoI, trapping sequential stages of a two-metal-...

Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

DEFF Research Database (Denmark)

Thygesen, Lisbeth Garbrecht; Hidayat, Budi Juliman; Johansen, Katja Salomon

2011-01-01

The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes ...... the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels....

Enzymatic hydrolysis and fermentation of agricultural residues to ethanol

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

1984-01-01

A combined enzymatic hydrolysis and fermentation process was used to convert steam-treated wheat and barley straw to ethanol. Maximum conversion efficiencies were obtained when the substrates were steamed for 90 s. These substrates could yield over 0.4 g ethanol/g cellulose following a combined enzymatic hydrolysis and fermentation process procedure using culture filtrates derived from Trichoderma harzianum E58. When culture filtrates from Trichoderma reesei C30 and T. reesei QM9414 were used, the ethanol yields obtained were 0.32 and 0.12 g ethanol/g cellulose utilized, respectively. The lower ethanol yields obtained with these strains were attributed to the lower amounts of ..beta..-glucosidase detected in the T. reesei culture filtrates.

Effect of Limited Hydrolysis on Traditional Soy Protein Concentrate

Directory of Open Access Journals (Sweden)

Mirjana B. Pesic

2006-09-01

Full Text Available The influence of limited proteolysis of soy protein concentrate on proteinextractability, the composition of the extractable proteins, their emulsifying properties andsome nutritional properties were investigated. Traditional concentrate (alcohol leachedconcentrate was hydrolyzed using trypsin and pepsin as hydrolytic agents. Significantdifferences in extractable protein composition between traditional concentrate and theirhydrolysates were observed by polyacrylamide gel electrophoresis (PAGE and by SDSPAGE.All hydrolysates showed better extractability than the original protein concentrate,whereas significantly better emulsifying properties were noticed at modified concentratesobtained by trypsin induced hydrolysis. These improved properties are the result of twosimultaneous processes, dissociation and degradation of insoluble alcohol-induced proteinaggregates. Enzyme induced hydrolysis had no influence on trypsin-inibitor activity, andsignificantly reduced phytic acid content.

Kunitz trypsin inhibitor in addition to Bowman-Birk inhibitor influence stability of lunasin against pepsin-pancreatin hydrolysis.

Science.gov (United States)

Price, Samuel J; Pangloli, Philipus; Krishnan, Hari B; Dia, Vermont P

2016-12-01

Soybean contains several biologically active components and one of this belongs to the bioactive peptide group. The objectives of this study were to produce different lunasin-enriched preparations (LEP) and determine the effect of Bowman-Birk inhibitor (BBI) and Kunitz trypsin inhibitor (KTI) concentrations on the stability of lunasin against pepsin-pancreatin hydrolysis (PPH). In addition, the effect of KTI mutation on lunasin stability against PPH was determined. LEP were produced by calcium and pH precipitation methods of 30% aqueous ethanol extract from defatted soybean flour. LEP, lunasin-enriched commercially available products and KTI control and mutant flours underwent PPH and samples were taken after pepsin and pepsin-pancreatin hydrolysis. The concentrations of BBI, KTI, and lunasin all decreased after hydrolysis, but they had varying results. BBI concentration ranged from 167.5 to 655.8μg/g pre-hydrolysis and 171.5 to 250.1μg/g after hydrolysis. KTI concentrations ranged from 0.3 to 122.3μg/g pre-hydrolysis and 9.0 to 18.7μg/g after hydrolysis. Lunasin concentrations ranged from 8.5 to 71.0μg/g pre-hydrolysis and 4.0 to 13.2μg/g after hydrolysis. In all products tested, lunasin concentration after PPH significantly correlated with BBI and KTI concentrations. Mutation in two KTI isoforms led to a lower concentration of lunasin after PPH. This is the first report on the potential role of KTI in lunasin stability against PPH and must be considered in designing lunasin-enriched products that could potentially survive digestion after oral ingestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of bovine serum albumin (BSA) on enzymatic cellulose hydrolysis.

Science.gov (United States)

Wang, Hui; Mochidzuki, Kazuhiro; Kobayashi, Shinichi; Hiraide, Hatsue; Wang, Xiaofen; Cui, Zongjun

2013-06-01

Bovine serum albumin (BSA) was added to filter paper during the hydrolysis of cellulase. Adding BSA before the addition of the cellulase enhances enzyme activity in the solution, thereby increasing the conversion rate of cellulose. After 48 h of BSA treatment, the BSA adsorption quantities are 3.3, 4.6, 7.8, 17.2, and 28.3 mg/g substrate, each with different initial BSA concentration treatments at 50 °C; in addition, more cellulase was adsorbed onto the filter paper at 50 °C compared with 35 °C. After 48 h of hydrolysis, the free-enzyme activity could not be measured without the BSA treatment, whereas the remaining activity of the filter paper activity was approximately 41 % when treated with 1.0 mg/mL BSA. Even after 96 h of hydrolysis, 25 % still remained. Meanwhile, after 48 h of incubation without substrate, the remaining enzyme activities were increased 20.7 % (from 43.7 to 52.7 %) and 94.8 % (from 23.3 to 45.5 %) at 35 and 50 °C, respectively. Moreover, the effect of the BSA was more obvious at 35 °C compared with 50 °C. When using 15 filter paper cellulase units per gram substrate cellulase loading at 50 °C, the cellulose conversion was increased from 75 % (without BSA treatment) to ≥90 % when using BSA dosages between 0.1 and 1.5 mg/mL. Overall, these results suggest that there are promising strategies for BSA treatment in the reduction of enzyme requirements during the hydrolysis of cellulose.

The effect of pH, temperature and plaque thickness on the hydrolysis of monofluorophosphate in experimental dental plaque.

Science.gov (United States)

Pearce, E I F; Dibdin, G H

2003-01-01

Monofluorophosphate (MFP), an anti-caries agent commonly used in toothpaste, is known to be degraded to fluoride and orthophosphate by bacterial phosphatases in dental plaque. We have examined the effect of pH, temperature, plaque thickness and some ions on this process. Both natural plaque and artificial microcosm plaque incubated with purified MFP at pH 4-10 showed an optimum pH of approximately 8 for hydrolysis. Diffusion and concomitant hydrolysis were examined in an apparatus in which artificial plaque was held between rigid membranes separating two chambers. When MFP diffused through a plaque of 0.51-mm thickness over 4 h it was almost completely hydrolysed at pH 8, but hydrolysis on diffusion decreased as the pH deviated from 8. MFP in toothpaste extract showed a similar pH susceptibility to hydrolysis, according to the inherent pH of the toothpaste. Hydrolysis of MFP in the toothpaste was reduced by no more than 10% when compared with a matched-pH control, suggesting that other toothpaste ingredients had no major influence on hydrolysis. Transport was slower and hydrolysis at pH 6 more complete the thicker the plaque, but hydrolysis was not significantly slower at 23 degrees C than at 37 degrees C. The addition of various potential activating or inhibiting ions at 0.1 and 1.0 mmol/l had small and non-significant effects on hydrolysis. The results suggest that MFP toothpaste should be formulated and used to maximise enzymic hydrolysis of this complex anion, and that plaque pH control is probably the most important factor. Copyright 2003 S. Karger AG, Basel

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

Science.gov (United States)

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Monitoring of soluble starch hydrolysis induced by α-amylase from Aspergillus oryzae using ultrasonic spectroscopy

Science.gov (United States)

Sierra, Carlos; Resa, Pablo; Buckin, Vitaly; Elvira, Luis

2012-05-01

The online monitoring of enzymatic starch hydrolysis is an important issue for several industrial sectors, mainly in the alimentary industry. Ultrasonic non-invasive methods based on the detection of wave velocity and amplitude changes can be used to study this enzymatic reaction. These wave propagating changes are result of physicalchemical modifications produced in the media by the starch hydrolysis. In this work the starch hydrolysis induced by the enzyme α-amylase from Aspergillus oryzae is studied. This biochemical reaction has been monitored using a high-resolution ultrasonic spectroscopy (HR-US) which is non-invasive and nondestructive. The measured time profiles o of ultrasonic velocity are explained in terms of the starch hydrolysis and the subsequent production of oligosaccharides as a consequence of the enzymatic action. The obtained results have been compared to a conventional off-line technique used in biochemistry, the iodine-starch reaction, a spectrophotometric method to quantify the amount of starch remaining in the medium. The combination of these two types of measurement provides more complete information about the biochemical processes occurred during hydrolysis.

Water-assisted and thermally-enhanced protonic conduction in HZSM-5, effect of gamma-irradiation on the electric properties. [Zeolites

Energy Technology Data Exchange (ETDEWEB)

Higazy, A.A.; Kassem, M.E. (Qatar Univ. (Qatar). Physics Dept.); Sayed, M.B. (Qatar Univ. (Qatar). Chemistry Dept.)

1992-01-01

Analysis of the a.c. conductivity of the zeolite HZSM-5, in the 0.1-100 kHz frequency region and the 300-700 K temperature range, reveals semiconducting features based predominantly on an ionic mechanism. This is reflected in a low-frequency Cole-Cole dependence of the Z''(Z') impedance and in a linear dependence of the {epsilon}''(''epsilon''') dielectric constant throughout the temperature range. The zeolite Broensted sites are the active centers responsible for the ionic conduction. As the conductivity drops to 373 K, sorbed water seems to participate in the conduction as a vehicle assisting the proton mobility. Above 373 K, the conductivity continues to rise as an indication of critical transition into a thermally enhanced ionic conduction. Both low-temperature sorbed water and high-temperature thermal motion are necessary to ensure a firm contact at the aggregate surfaces, where conduction takes place. Gamma-irradiation also participates in the conduction by creating new sites sensitive to the same parameters governing the conduction mechanism. (author).

Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

Science.gov (United States)

Olanrewaju, Kazeem Bode

The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

Barley grain constituents, starch composition, and structure affect starch in vitro enzymatic hydrolysis.

Science.gov (United States)

Asare, Eric K; Jaiswal, Sarita; Maley, Jason; Båga, Monica; Sammynaiken, Ramaswami; Rossnagel, Brian G; Chibbar, Ravindra N

2011-05-11

The relationship between starch physical properties and enzymatic hydrolysis was determined using ten different hulless barley genotypes with variable carbohydrate composition. The ten barley genotypes included one normal starch (CDC McGwire), three increased amylose starches (SH99250, SH99073, and SB94893), and six waxy starches (CDC Alamo, CDC Fibar, CDC Candle, Waxy Betzes, CDC Rattan, and SB94912). Total starch concentration positively influenced thousand grain weight (TGW) (r(2) = 0.70, p starch concentration (r(2) = -0.80, p hydrolysis of pure starch (r(2) = -0.67, p starch concentration (r(2) = 0.46, p starch (RS) in meal and pure starch samples. The rate of starch hydrolysis was high in pure starch samples as compared to meal samples. Enzymatic hydrolysis rate both in meal and pure starch samples followed the order waxy > normal > increased amylose. Rapidly digestible starch (RDS) increased with a decrease in amylose concentration. Atomic force microscopy (AFM) analysis revealed a higher polydispersity index of amylose in CDC McGwire and increased amylose genotypes which could contribute to their reduced enzymatic hydrolysis, compared to waxy starch genotypes. Increased β-glucan and dietary fiber concentration also reduced the enzymatic hydrolysis of meal samples. An average linkage cluster analysis dendrogram revealed that variation in amylose concentration significantly (p starch concentration in meal and pure starch samples. RS is also associated with B-type granules (5-15 μm) and the amylopectin F-III (19-36 DP) fraction. In conclusion, the results suggest that barley genotype SH99250 with less decrease in grain weight in comparison to that of other increased amylose genotypes (SH99073 and SH94893) could be a promising genotype to develop cultivars with increased amylose grain starch without compromising grain weight and yield.

Direct analysis of anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption-dielectric barrier discharge ionization mass spectrometry.

Science.gov (United States)

Saha, Subhrakanti; Mandal, Mridul Kanti; Nonami, Hiroshi; Hiraoka, Kenzo

2014-08-11

Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05-0.1 ng mL(-1) for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine. Copyright © 2014 Elsevier B.V. All rights reserved.

Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiao; Zheng, Maoyu; Zhang, Wenyong; Zhang, Shu; Yang, Tao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, NO 202 Haihe Road, Harbin, Hei Longjiang 150090 (China)

2010-11-15

This paper presents the experimental study of a solar-assisted ground-coupled heat pump system (SAGCHPS) with solar seasonal thermal storage installed in a detached house in Harbin. The solar seasonal thermal storage was conducted throughout the non-heating seasons. In summer, the soil was used as the heat sink to cool the building directly. In winter, the solar energy was used as a priority, and the building was heated by a ground-coupled heat pump (GCHP) and solar collectors alternately. The results show that the system can meet the heating-cooling energy needs of the building. In the heating mode, the heat directly supplied by solar collectors accounted for 49.7% of the total heating output, and the average coefficient of performance (COP) of the heat pump and the system were 4.29 and 6.55, respectively. In the cooling mode, the COP of the system reached 21.35, as the heat pump was not necessary to be started. After a year of operation, the heat extracted from the soil by the heat pump accounted for 75.5% of the heat stored by solar seasonal thermal storage. The excess heat raised the soil temperature to a higher level, which was favorable for increasing the COP of the heat pump. (author)

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

Science.gov (United States)

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.

Enzymatic Hydrolysis of Pretreated Fibre Pressed Oil Palm Frond by using Sacchariseb C6

Science.gov (United States)

Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Rahman, R. A.; Illias, R. M.

2017-06-01

Enzymatic hydrolysis becomes a prominent technology for conversion of cellulosic biomass to its glucose monomers that requires an action of cellulolytic enzymes in a sequential and synergistic manner. In this study, the effect of agitation speed, glucan loading, enzyme loading, temperature and reaction time on the production of glucose from fibre pressed oil palm frond (FPOPF) during enzymatic hydrolysis was screened by a half factorial design 25-1 using Response Surface Methodology (RSM). The FPOPF sample was first delignified by alkaline pretreatment at 4.42 (w/v) sodium hydroxide for an hour prior to enzymatic hydrolysis using commercial cellulase enzyme, Sacchariseb C6. The effect of enzymatic hydrolysis on the structural of FPOPF has been evaluated by Scanning Electron Microscopy (SEM) analysis. Characterization of raw FPOPF comprised of 4.5 extractives, 40.7 glucan, 26.1 xylan, 26.2 lignin and 1.8 ash, whereas for pretreated FPOPF gave 0.3 extractives, 61.4 glucan, 20.4 xylan, 13.3 lignin and 1.3 ash. From this study, it was found that the best enzymatic hydrolysis condition yielded 33.01 ± 0.73 g/L of glucose when performed at 200 rpm of agitation speed, 60 FPU/mL of enzyme loading, 4 (w/w) of glucan loading, temperature at 55 □ and 72 hours of reaction time. The model obtained was significant with p-value enzymatic hydrolysis from pretreated FPOPF produce high amount of glucose that enhances it potential for industrial application. This glucose can be further used to produce high-value products.

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

International Nuclear Information System (INIS)

Ardica, S.; Calderaro, E.; Cappadona, C.

1985-01-01

The effect of γ-ray pre-irradiation of cellulose materials such as wood chips, paper, grain straw, hay and kapok on glucose production on enzymatic hydrolysis by cellulase has been investigated. These materials have been irradiated in air, water and acetate buffer solution over the dose range 10 3 to 4 x 10 6 Gy. In the relatively low dose range, up to about 5 x 10 5 Gy, the glucose yields after enzymatic hydrolysis are practically insensitive to radiation. At higher dose levels, up to 1.7 to 2 x 10 6 Gy, the pre-irradiation becomes very effective on enzymatic cellulose conversion. It has been found that the radiation-induced degradation of cellulose into low molecular weight polysaccharides is dependent on the nature and chemical composition of the cellulose materials and on the radiation environmental conditions. Further increases of dose causes radiation-induced structural modifications in polysaccharides previously produced, which can lead to a decrease in glucose production by enzymatic hydrolysis. (author)

Influence of fine grinding on the hydrolysis of cellulosic materials - acid vs enzymic

Energy Technology Data Exchange (ETDEWEB)

Millet, M A; Effland, M J; Caulfield, D F

1979-01-01

The effect of vibratory milling on the enzymic and dilute H/sub 2/SO/sub 4/ hydrolysis of cotton linters, newsprint, Douglas fir, and red oak was investigated by determining the rate and degree of hydrolysis, maximum yield of reducing sugars, and cellulose crystallinity index. Linters were totally hydrolyzed in 10 days after 60 min milling; oak carbohydrates were 93% convertible to sugar in the same period after 240 min milling. Vibratory milling substantially increased the rates of acid hydrolysis of all 4 substrates, nearly 9- and 5-fold for linters and other lignocellulosic materials, respectively. Increases in maximum sugar yields under batch conditions were 60 to 140% higher than those for unmilled materials.

The preparation of lithium aluminate by the hydrolysis of lithium and aluminum alkoxides

International Nuclear Information System (INIS)

Turner, C.W.; Clatworthy, B.C.; Gin, A.Y.H.

1987-10-01

Lithium aluminate was prepared by heating the hydrolysis products from various combinations of lithium and aluminum alkoxides under an atmosphere of nitrogen. The product was β-LiA1O 2 when aluminum iso-propoxide was a starting material, whereas γ-LiA1O 2 was the product for preparations starting with aluminum n-butoxide. The results were independent of the choice of lithium alkoxide. The hydrolysis of aluminum sec-butoxide with a solution of LiOH led to the γ phase as well. The temperature at which the γ phase developed depended upon the conditions of the hydrolysis reaction and was observed at a temperature as low as 550 degrees Celcius

Green thermal-assisted synthesis and characterization of novel cellulose-Mg(OH)2 nanocomposite in PEG/NaOH solvent.

Science.gov (United States)

Ponomarev, Nikolai; Repo, Eveliina; Srivastava, Varsha; Sillanpää, Mika

2017-11-15

Synthesis of nanocomposites was performed using microcrystalline cellulose (MCC), MgCl 2 in PEG/NaOH solvent by a thermal-assisted method at different temperatures by varying time and the amount of MCC. Results of XRD, FTIR, and EDS mapping showed that the materials consisted of only cellulose (CL) and magnesium hydroxide (MH). According to FTIR and XRD, it was found that crystallinity of MH in cellulose nanocomposites is increased with temperature and heating time and decreased with increasing of cellulose amount. The PEG/NaOH solvent has a significant effect on cellulose and Mg(OH) 2 morphology. BET and BJH results demonstrated the effects of temperature and cellulose amount on the pore size corresponding to mesoporous materials. TG and DTG analyses showed the increased thermal stability of cellulose nanocomposites with increasing temperature. TEM and SEM analyses showed an even distribution of MH nanostructures with various morphology in the cellulose matrix. The cellulose presented as the polymer matrix in the nanocomposites. It was supposed the possible interaction between cellulose and Mg(OH) 2 . The novel synthesis method used in this study is feasible, cost-efficient and environmentally friendly. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of steam treatment on the hydrolysis of aspen by commerical enzymes

Energy Technology Data Exchange (ETDEWEB)

Macdonald, D G; Mathews, J F

1979-06-01

Steam treatment renders aspen wood more susceptible to hydrolysis by commerical enzyme preparations such as the Onozuka variety. The main products of enzymatic hydrolysis are glucose, xylose, and xylobiose. Cellobiose may have been another product but it could not be measured due to interference by lactose, a sugar found in the enzyme. The hemicellulose fraction of the wood is relatively more rapidly hydrolyzed by the enzymes than the cellulose fraction.

Interdependence of the kinetics of NTP hydrolysis and the stability of the RecA-ssDNA complex.

Science.gov (United States)

Katz, F S; Bryant, F R

2001-09-18

The ssDNA-dependent NTP hydrolysis activity of the RecA protein was examined using a series of dTn oligomers ranging in size from dT10 to dT2000 as the ssDNA effector. There were three distinct manifestations of the dTn-dependent NTP hydrolysis reaction, depending on the length of the dTn effector that was used. With longer dTn oligomers, NTP hydrolysis occurred with a turnover number of 20-25 min(-1) and the observed S0.5 value for the NTP was independent of the concentration of the dTn oligomer (DNA concentration-independent hydrolysis). With dTn oligomers of intermediate length, NTP hydrolysis still occurred with a turnover number of 20-25 min(-1), but the observed S0.5 for the NTP decreased with increasing dTn concentration until reaching a value similar to that obtained with the longer dTn oligomers (DNA concentration-dependent hydrolysis). With shorter dTn oligomers, the NTP hydrolysis activity was effectively eliminated. Although this general progression of kinetic behavior was observed for the three structurally related NTPs (dATP, ATP, and GTP), the dTn oligomer length at which DNA concentration-independent, DNA concentration-dependent, and no NTP hydrolysis was observed depended on the NTP being considered. For example, dATP (S0.5 = 35 microM) was hydrolyzed in the presence of dT20, whereas ATP (S0.5 = 70 microM) and GTP (S0.5 = 1200 microM) required at least dT50 and dT200 for hydrolysis, respectively. These results are discussed in terms of a kinetic model in which the stability of the RecA-ssDNA-NTP complex is dependent on the intrinsic S0.5 value of the NTP being hydrolyzed.

Hydrolysis kinetics of astaxanthin esters and stability of astaxanthin of Haematococcus pluvialis during saponification.

Science.gov (United States)

Yuan, J P; Chen, F

1999-01-01

The reaction kinetics for the hydrolysis of astaxanthin esters and the degradation of astaxanthin during saponification of the pigment extract from the microalga Haematococcus pluvialis were investigated. Different concentrations of sodium hydroxide in methanol were used for the saponification under nitrogen in darkness at ambient temperature (22 degrees C) followed by the analysis of astaxanthins and other carotenoids using an HPLC method. The concentration of methanolic NaOH solution was important for promoting the hydrolysis of astaxanthin esters and minimizing the degradation of astaxanthin during saponification. With a higher concentration of methanolic NaOH solution, the reaction rate of hydrolysis was high, but the degradation of astaxanthin occurred significantly. The rate constants of the hydrolysis reaction (first order) of astaxanthin esters and the degradation reaction (zero-order) of astaxanthin were directly proportional to the concentration of sodium hydroxide in the saponified solution. Although the concentration of sodium hydroxide in the saponified solution was 0.018 M, complete hydrolysis of astaxanthin esters was achieved in 6 h for different concentrations (10-100 mg/L) of pigment extracts. Results also indicated that a higher temperature should be avoided to minimize the degradation of astaxanthin. In addition, during saponification, no loss of lutein, beta-carotene, and canthaxanthin was found.

Product sampling during transient continuous countercurrent hydrolysis of canola oil and development of a kinetic model

KAUST Repository

Wang, Weicheng

2013-11-01

A chemical kinetic model has been developed for the transient stage of the continuous countercurrent hydrolysis of triglycerides to free fatty acids and glycerol. Departure functions and group contribution methods were applied to determine the equilibrium constants of the four reversible reactions in the kinetic model. Continuous countercurrent hydrolysis of canola oil in subcritical water was conducted experimentally in a lab-scale reactor over a range of temperatures and the concentrations of all neutral components were quantified. Several of the rate constants in the model were obtained by modeling this experimental data, with the remaining determined from calculated equilibrium constants. Some reactions not included in the present, or previous, hydrolysis modeling efforts were identified from glycerolysis kinetic studies and may explain the slight discrepancy between model and experiment. The rate constants determined in this paper indicate that diglycerides in the feedstock accelerate the transition from "emulsive hydrolysis" to "rapid hydrolysis". © 2013 Elsevier Ltd.

Comparison of sodium borohydride hydrolysis kinetics on Co-based nanocomposite catalysts

International Nuclear Information System (INIS)

Hristov, Georgi; Chorbadzhiyska, Elitsa; Mitov, Mario; Rashkov, Rashko; Hubenova, Yolina

2011-01-01

In this study, we compared the results, obtained with several Co-based nanocomposites (CoMnB, CoNiMnB and CoNiMoW) produced by electrodeposition on Ni-foam, as catalysts for the sodium borohydride hydrolysis reaction. Based on the comparative analyses, we propose CoNiMnB electrodeposits as most suitable catalysts for development of Hydrogen-on-Demand (HOD) system, while CoNiMoW ones as potential anodes for Direct Borohydride Fuel Cells (DBFCs). Keywords: Hydrogen-on-Demand (HOD), Nanocomposites, Hydrolysis, Catalyst, Kinetic

Response surface optimization of enzymatic hydrolysis of narrow-leaf cattail for bioethanol production

International Nuclear Information System (INIS)

Ruangmee, Arrisa; Sangwichien, Chayanoot

2013-01-01

Highlights: • The cellulose of pretreated sample was higher than untreated sample. • Lower hemicellulose and lignin were enhanced of hydrolyzed cellulose to sugar. • The predicted result of enzymatic hydrolysis process was fitted by quadratic model. • Predicted data was good agreement with the experimental data; with 95% confidence. - Abstract: Narrow-leaf cattail was employed as lignocellulosic biomass substrate for the investigation of the hydrolysis process of lignocellulosic ethanol. Cellulose saccharification into a high yield of fermentable sugar is an important step in ethanol production. Response surface methodology was utilized in the study of variables affecting enzymatic hydrolysis on the released glucose and xylose. Five levels (−2, −1, 0, +1, +2) of independent variable factors; cellulase (5–25 FPU/g substrate), β-glucosidase (0–20 U/g substrate), hydrolysis temperature (30–50 °C), and hydrolysis time (24–96 h), were randomly setup by using the Design of Experiment program. The significance of the regression model was high; with 95% confidence interval (less than 5% error). The predicted result after optimization was also in good agreement with the experimental data. An optimal condition; 13.50 FPU/g substrate, 16.50 U/g substrate, 50 °C and 24 h, was obtained, yielding a released glucose of 552.9 mg/g substrate (75.6% saccharification) and a released xylose of 74.0 mg/g substrate (45.6% saccharification)

Comparison of response surface methodology and artificial neural network to enhance the release of reducing sugars from non-edible seed cake by autoclave assisted HCl hydrolysis.

Science.gov (United States)

Shet, Vinayaka B; Palan, Anusha M; Rao, Shama U; Varun, C; Aishwarya, Uday; Raja, Selvaraj; Goveas, Louella Concepta; Vaman Rao, C; Ujwal, P

2018-02-01

In the current investigation, statistical approaches were adopted to hydrolyse non-edible seed cake (NESC) of Pongamia and optimize the hydrolysis process by response surface methodology (RSM). Through the RSM approach, the optimized conditions were found to be 1.17%v/v of HCl concentration at 54.12 min for hydrolysis. Under optimized conditions, the release of reducing sugars was found to be 53.03 g/L. The RSM data were used to train the artificial neural network (ANN) and the predictive ability of both models was compared by calculating various statistical parameters. A three-layered ANN model consisting of 2:12:1 topology was developed; the response of the ANN model indicates that it is precise when compared with the RSM model. The fit of the models was expressed with the regression coefficient R 2 , which was found to be 0.975 and 0.888, respectively, for the ANN and RSM models. This further demonstrated that the performance of ANN was better than that of RSM.

How Cations Can Assist DNase I in DNA Binding and Hydrolysis

Science.gov (United States)

Guéroult, Marc; Picot, Daniel; Abi-Ghanem, Joséphine; Hartmann, Brigitte; Baaden, Marc

2010-01-01

DNase I requires Ca2+ and Mg2+ for hydrolyzing double-stranded DNA. However, the number and the location of DNase I ion-binding sites remain unclear, as well as the role of these counter-ions. Using molecular dynamics simulations, we show that bovine pancreatic (bp) DNase I contains four ion-binding pockets. Two of them strongly bind Ca2+ while the other two sites coordinate Mg2+. These theoretical results are strongly supported by revisiting crystallographic structures that contain bpDNase I. One Ca2+ stabilizes the functional DNase I structure. The presence of Mg2+ in close vicinity to the catalytic pocket of bpDNase I reinforces the idea of a cation-assisted hydrolytic mechanism. Importantly, Poisson-Boltzmann-type electrostatic potential calculations demonstrate that the divalent cations collectively control the electrostatic fit between bpDNase I and DNA. These results improve our understanding of the essential role of cations in the biological function of bpDNase I. The high degree of conservation of the amino acids involved in the identified cation-binding sites across DNase I and DNase I-like proteins from various species suggests that our findings generally apply to all DNase I-DNA interactions. PMID:21124947

Heavy-Duty Vehicle Thermal Management | Transportation Research | NREL

Science.gov (United States)

Heavy-Duty Vehicle Thermal Management Heavy-Duty Vehicle Thermal Management Infrared image of a control materials and equipment on heavy-duty vehicles. Photo by Dennis Schroeder, NREL Illustration of a Ray David, NREL National Renewable Energy Laboratory (NREL) researchers are assisting heavy-duty

Numerical prediction of kinetic model for enzymatic hydrolysis of cellulose using DAE-QMOM approach

Science.gov (United States)

Jamil, N. M.; Wang, Q.

2016-06-01

Bioethanol production from lignocellulosic biomass consists of three fundamental processes; pre-treatment, enzymatic hydrolysis, and fermentation. In enzymatic hydrolysis phase, the enzymes break the cellulose chains into sugar in the form of cellobiose or glucose. A currently proposed kinetic model for enzymatic hydrolysis of cellulose that uses population balance equation (PBE) mechanism was studied. The complexity of the model due to integrodifferential equations makes it difficult to find the analytical solution. Therefore, we solved the full model of PBE numerically by using DAE-QMOM approach. The computation was carried out using MATLAB software. The numerical results were compared to the asymptotic solution developed in the author's previous paper and the results of Griggs et al. Besides confirming the findings were consistent with those references, some significant characteristics were also captured. The PBE model for enzymatic hydrolysis process can be solved using DAE-QMOM method. Also, an improved understanding of the physical insights of the model was achieved.

Coordination of substrate binding and ATP hydrolysis in Vps4-mediated ESCRT-III disassembly.

Science.gov (United States)

Davies, Brian A; Azmi, Ishara F; Payne, Johanna; Shestakova, Anna; Horazdovsky, Bruce F; Babst, Markus; Katzmann, David J

2010-10-01

ESCRT-III undergoes dynamic assembly and disassembly to facilitate membrane exvagination processes including multivesicular body (MVB) formation, enveloped virus budding, and membrane abscission during cytokinesis. The AAA-ATPase Vps4 is required for ESCRT-III disassembly, however the coordination of Vps4 ATP hydrolysis with ESCRT-III binding and disassembly is not understood. Vps4 ATP hydrolysis has been proposed to execute ESCRT-III disassembly as either a stable oligomer or an unstable oligomer whose dissociation drives ESCRT-III disassembly. An in vitro ESCRT-III disassembly assay was developed to analyze Vps4 function during this process. The studies presented here support a model in which Vps4 acts as a stable oligomer during ATP hydrolysis and ESCRT-III disassembly. Moreover, Vps4 oligomer binding to ESCRT-III induces coordination of ATP hydrolysis at the level of individual Vps4 subunits. These results suggest that Vps4 functions as a stable oligomer that acts upon individual ESCRT-III subunits to facilitate ESCRT-III disassembly.

TL and ESR based identification of gamma-irradiated frozen fish using different hydrolysis techniques

Science.gov (United States)

Ahn, Jae-Jun; Akram, Kashif; Shahbaz, Hafiz Muhammad; Kwon, Joong-Ho

2014-12-01

Frozen fish fillets (walleye Pollack and Japanese Spanish mackerel) were selected as samples for irradiation (0-10 kGy) detection trials using different hydrolysis methods. Photostimulated luminescence (PSL)-based screening analysis for gamma-irradiated frozen fillets showed low sensitivity due to limited silicate mineral contents on the samples. Same limitations were found in the thermoluminescence (TL) analysis on mineral samples isolated by density separation method. However, acid (HCl) and alkali (KOH) hydrolysis methods were effective in getting enough minerals to carry out TL analysis, which was reconfirmed through the normalization step by calculating the TL ratios (TL1/TL2). For improved electron spin resonance (ESR) analysis, alkali and enzyme (alcalase) hydrolysis methods were compared in separating minute-bone fractions. The enzymatic method provided more clear radiation-specific hydroxyapatite radicals than that of the alkaline method. Different hydrolysis methods could extend the application of TL and ESR techniques in identifying the irradiation history of frozen fish fillets.

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

Directory of Open Access Journals (Sweden)

Sonia L. Repetto

2016-07-01

Full Text Available A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII. To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel–water interface (D2O/CD3CN 1:4. We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses.

The Isolation of Nanofibre Cellulose from Oil Palm Empty Fruit Bunch Via Steam Explosion and Hydrolysis with HCl 10%

Science.gov (United States)

Gea, S.; Zulfahmi, Z.; Yunus, D.; Andriayani, A.; Hutapea, Y. A.

2018-03-01

Cellulose nanofibrils were obtained from oil palm empty fruit bunch using steam explosion and hydrolized with 10% solution of HCl. Steam explosion coupled with acid hydrolysis pretreatment on the oil palm empty fruit bunch was very effective in the depolymerization and defibrillation process of the fibre to produce fibers in nanodimension. Structural analysis of steam exploded fibers was determined by Fourier Transform Infrared (FT-IR) spectroscopy. Thermal stability of cellulose measured using image analysis software image J. Characterization of the fibers by TEM and SEM displayed that fiber diameter decreases with mechanical-chemical treatment and final nanofibril size was 20-30 nm. FT-IR and TGA data confirmed the removal of hemicellulose and lignin during the chemical treatment process.

Experimental investigation on lithium hydride hydrolysis

International Nuclear Information System (INIS)

S Charton; F Delaunay; L Saviot; F Bernard; C Maupoix

2006-01-01

In order to have a better understanding of LiH reaction with water, several experimental techniques were investigated and tested to determine whether they were suitable or not in a kinetic purpose. Among them, Raman spectroscopy and X-Ray photoelectrons spectroscopy (XPS) gave particularly interesting results and are extensively used in the field of our kinetic and phenomenological study of H 2 production by LiH hydrolysis. (authors)

Promotion of H2 production by microwave-assisted treatment of water hyacinth with dilute H2SO4 through combined dark fermentation and photofermentation

International Nuclear Information System (INIS)

Cheng, Jun; Xia, Ao; Su, Huibo; Song, Wenlu; Zhou, Junhu; Cen, Kefa

2013-01-01

Highlights: • Water hyacinth is microwaved with dilute H 2 SO 4 to improve enzymatic hydrolysis. • Hydrolyzed hyacinth is fermented by hydrogenogens to improve dark H 2 yield. • Nearly 100% glucose and most arabinose in hydrolysate are used in dark fermentation. • H 2 yield from hyacinth via combined fermentation is 75.2% of theoretical H 2 yield. - Abstract: Water hyacinth was treated with microwave-assisted dilute H 2 SO 4 to improve saccharification before enzymatic hydrolysis and H 2 production during dark fermentation. A maximum reducing sugar (RS) yield of 64.4 g/100 g total volatile solid (TVS) (96.1% of the theoretical RS yield) was achieved when water hyacinth was treated through microwave heating with 1% dilute H 2 SO 4 for 15 min at 140 °C and then enzymatically hydrolyzed for 72 h. During enzymatic hydrolysis, glucose was efficiently produced from the hydrolysis of cellulose that resulted from the disruption of the lignocellulosic structure of water hyacinth after microwave-assisted H 2 SO 4 treatment. When the hydrolyzed water hyacinth was inoculated with H 2 -producing bacteria to produce H 2 during dark fermentation, a maximum H 2 yield of 112.3 ml/g TVS was obtained. The major sugar compositions in the residual solution from dark fermentation were xylose and cellobiose (total RS utilization efficiency: 88.5%). Through a combination of dark fermentation and photofermentation, the maximum H 2 yield from water hyacinth was significantly increased from 112.3 ml/g TVS to 751.5 ml/g TVS, which is 75.2% of the theoretical H 2 yield

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

Science.gov (United States)

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. Copyright © 2013 Elsevier Ltd. All rights reserved.

What does the hydrolysis perform in the fermentation of biogas? Biogas, hydrolysis, fermenter biology, multistage process operation; Was kann die Hydrolyse bei der Biogasvergaerung leisten? Biogas, Hydrolyse, Fermenterbiologie, mehrphasige Prozessfuehrung

Energy Technology Data Exchange (ETDEWEB)

Oechsner, H.; Lemmer, A. [Landesanstalt fuer Agrartechnik und Bioenergie, Univ. Hohenheim, Stuttgart (Germany)

2009-07-01

Nowadays renewable primary products are normally favored for fermentation in agricultural biogas plants. Since this substrate has to be cultivated for biogas fermentation in particular and hence causes production costs, the energy content of the material should be dissipated in biogas completely. For this the fermentation process has to run as efficient as possible. In case of one-phase process management with high space loading there is a risk of imbalance and maybe even collapse of process biology in the fermenter. In case of high space loading and short retention time the substrate won't be fermented completely. The aim is to create good conditions for microorganism participating in the process by a two-phase process management which integrates a stage of hydrolysis. In the stage of hydrolysis the microorganisms and enzymes metabolize the organic matter into readily biodegradable carbonic acids, which can be supplied targeted in the following methanisation as substrate for methanogenic bacteria. The hydrolysis proceeds under various terms and conditions (aerobic/anaerobic, different pH-value, different temperature level). This necessitates a safe control of operation and process parameters, which is often difficult to ensure in practice. In a malfunctioning hydrolysis also methane can be produced, that causes energy losses and environmental damage when emitted in atmosphere. Hydrogen can be produced in the hydrolysis as well what can involve a safety risk. Urgent need for research exists concerning the two-phase fermentation of renewable primary products. By systematic laboratory analysis the knowledge should be expanded, to improve the planning reliability in this field. (orig.)

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Marya Aziz

2015-01-01

Full Text Available 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.

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

Science.gov (United States)

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.

COMPARISON OF PRETREATMENT STRATEGIES FOR CONVERSION OF COCONUT HUSK FIBER TO FERMENTABLE SUGARS

Directory of Open Access Journals (Sweden)

Teck Y. Ding,

2012-02-01

Full Text Available In the present study, coconut husk was employed as biomass feedstock for production of bioethanol, due to its abundance in Malaysia. Due to the complex structures of coconut husk, a pretreatment process is crucial in extracting fermentable sugars from the embedded cellulose matrix for subsequent ethanol fermentation process. The ground coconut husk was subjected to three different pretreatment processes inclusive of thermal, chemical, and microwave-assisted-alkaline techniques, prior to enzymatic hydrolysis and fermentation process. The composition profile of coconut husk was significantly altered upon the microwave-assisted-alkaline treatment as compared to the untreated sample, with the cellulose content increasing from 18-21% to 38-39% while lignin content decreased from 46-53% to 31-33%. Among the pretreatment methods applied, enzymatic hydrolysis of coconut husk pretreated by microwave-assisted-alkaline method recorded the highest yield of fermentable sugars, 0.279 g sugar/g substrate. SEM imaging showed the obvious and significant disruption of coconut husks’ structure after microwave-assisted-alkaline pretreatment. In conclusion, by employing suitable pretreatment technique in treating the lignocellulosic materials of coconut husk, the extracted fermentable sugar is a potential substrate for bioethanol production.

Enzymatic hydrolysis of lactose of whey permeate

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Karina Nascimento de Almeida

2015-09-01

Full Text Available The whey permeate is the residual of the concentration process of the whey proteins by ultrafiltration method. It contains important nutrients such as lactose, minerals and some proteins and lipids. It is without an ending industrial waste that causes serious damage to the environment. For its full use the lactose must be hydrolyzed to enable its consumption by intolerant people. The enzymatic hydrolysis by lactase (β-galactosidase of Kluyveromyces lactis yeast is a safe method that does not compromise the integrity of other nutrients, enabling further use of the permeate as a raw material. This study aimed to perform tests of enzymatic hydrolysis of lactose in whey permeate formulations in a concentration of 0.2%, 0.7% and 1% at 30, 60 and 90 minutes with pH 6.3 medium and 37 °C. The reactions were monitored by high performance liquid chromatography which showed that the enzyme concentration of 0.7% at time 30 minutes formulations became safe for consumption by lactose intolerant people, according to minimum levels established by law.

Hydrolysis of solid ammonia borane

Energy Technology Data Exchange (ETDEWEB)

Demirci, Umit B.; Miele, Philippe [Universite Lyon 1, CNRS, UMR 5615, Laboratoire des Multimateriaux et Interfaces, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France)

2010-07-01

Ammonia borane NH{sub 3}BH{sub 3} is a promising hydrogen storage material by virtue of a theoretical gravimetric hydrogen storage capacity (GHSC) of 19.5 wt%. However, stored hydrogen has to be effectively released, one way of recovering this hydrogen being the metal-catalyzed hydrolysis. The present study focuses on CoCl{sub 2}-catalyzed hydrolysis of NH{sub 3}BH{sub 3} with the concern of improving the effective GHSC of the system NH{sub 3}BH{sub 3}-H{sub 2}O. For that, NH{sub 3}BH{sub 3} is stored as a solid and H{sub 2}O is provided in stoichiometric amount. By this way, an effective GHSC of 7.8 wt% has been reached at 25 C. To our knowledge, it is the highest value ever reported. Besides, one of the highest hydrogen generation rates (HGRs, 21 ml(H{sub 2}) min{sup -1}) has been found. In parallel, the increases of the water amount and temperature have been studied and the reaction kinetics has been determined. Finally, it has been observed that some NH{sub 3} release, what is detrimental for a fuel cell. To summarize, high performances in terms of GHSCs and HGRs can be reached with NH{sub 3}BH{sub 3} and since research devoted to this boron hydride is at the beginning we may be confident in making it viable in a near future. (author)

Aqueous two-phase systems for extractive enzymatic hydrolysis of biomass

DEFF Research Database (Denmark)

Bussamra, Bianca Consorti; Azzoni, Sindelia Freitas; Mussatto, Solange I.

and enzymes, phase diagrams and volumetric ratios. The results of this project will make possible to design a process that enables high sugar concentration during the hydrolysis reaction, overcoming one of the biggest drawbacks regarding the production of second-generation ethanol: the enzymatic inhibition...... optimal aqueous two-phase systems for the separation of sugars and enzymes, which allow the development of an improved second-generation ethanol process.......Sugars derived from lignocellulosic materials are the main carbon sources in bio-based processes aiming to produce renewable fuels and chemicals. One of the major drawbacks during enzymatic hydrolysis of lignocellulosic materials to obtainsugars is the inhibition of enzymes by reaction products...

Saliva-catalyzed hydrolysis of a ketobemidone ester prodrug

DEFF Research Database (Denmark)

Hansen, L.B.; Christrup, Lona Louring; Bundgaard, H.

1992-01-01

Saliva enzyme-catalysed hydrolysis of ester prodrugs or drugs containing sensitive ester groups may be a limiting factor for the buccal absorption of such compounds. Using the isopropyl carbonate ester of ketobemidone as a model substance of a hydrolysis-sensitive prodrug the esterase activity...... of human saliva has been characterized as a function of various factors. The esterase activity was found to decrease rapidly upon storage of the saliva at 37°C. The activity increased with increasing pH in the range 4.5-7.4 and with increasing salivation flow rate up to a rate of 0.9 ml min. Under resting...... conditions, the flow rate was about 0.2 ml min which implied a greatly decreased esterase activity. The activity was highest after fasting and decreased after intake of a meal. The intraindividual variation in the saliva esterase activity was small whereas a larger interindividual variation was found....

Solar thermal polymerase chain reaction for smartphone-assisted molecular diagnostics

Science.gov (United States)

Jiang, Li; Mancuso, Matthew; Lu, Zhengda; Akar, Gunkut; Cesarman, Ethel; Erickson, David

2014-02-01

Nucleic acid-based diagnostic techniques such as polymerase chain reaction (PCR) are used extensively in medical diagnostics due to their high sensitivity, specificity and quantification capability. In settings with limited infrastructure and unreliable electricity, however, access to such devices is often limited due to the highly specialized and energy-intensive nature of the thermal cycling process required for nucleic acid amplification. Here we integrate solar heating with microfluidics to eliminate thermal cycling power requirements as well as create a simple device infrastructure for PCR. Tests are completed in less than 30 min, and power consumption is reduced to 80 mW, enabling a standard 5.5 Wh iPhone battery to provide 70 h of power to this system. Additionally, we demonstrate a complete sample-to-answer diagnostic strategy by analyzing human skin biopsies infected with Kaposi's Sarcoma herpesvirus (KSHV/HHV-8) through the combination of solar thermal PCR, HotSHOT DNA extraction and smartphone-based fluorescence detection. We believe that exploiting the ubiquity of solar thermal energy as demonstrated here could facilitate broad availability of nucleic acid-based diagnostics in resource-limited areas.

Hydrolysis and stability of thin pulsed plasma polymerised maleic anhydride coatings

DEFF Research Database (Denmark)

Drews, Joanna Maria; Launay, Héléne; Hansen, Charles M.

2008-01-01

Abstract The stability of plasma polymerised layers has become important because of their widespread use. This study explored the hydrolysis and degradation stability of coatings of plasma polymerised maleic anhydride. Coatings made with different plasma parameters were exposed to aqueous media...... of different pH as a function of time. ATR-FTIR was used for structure analysis and a toluidine blue staining method allowed quantitative analysis of the hydrolysis of anhydride groups to acid groups. Coatings with constant thickness were obtained at different plasma powers and layers with varying thickness...

Fluor determination by alkaline hydrolysis of the uranium and thorium fluorides

International Nuclear Information System (INIS)

Barrachina Gomez, L.; Gasco Sanchez, L.

1961-01-01

The alkaline hydrolysis of the uranium and thorium fluorides is studded and a new method for the determination of the fluoride, on the basis of a indirect volumetric titration with standard soda, is proposed. The compounds that may influence the hydrolysis of the uranium fluoride and that may be occasionally found in it as impurities are also studied. the method can be applied to the uranium fluoride except when there is a great quantity of F 2 UO 2 or UO 3 present in the sample. (Author) 20 refs