Relevant bibliographies by topics / Selective Hydrolysis

Academic literature on the topic 'Selective Hydrolysis'

Author: Grafiati
Published: 7 July 2024
Last updated: 7 July 2024

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Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Journal articles on the topic "Selective Hydrolysis":

1

Hooper, N. M., A. J. Kenny, and A. J. Turner. "The metabolism of neuropeptides. Neurokinin A (substance K) is a substrate for endopeptidase-24.11 but not for peptidyl dipeptidase A (angiotensin-converting enzyme)." Biochemical Journal 231, no. 2 (October 15, 1985): 357–61. http://dx.doi.org/10.1042/bj2310357.

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Both endopeptidase-24.11 and peptidyl dipeptidase A have previously been shown to hydrolyse the neuropeptide substance P. The structurally related peptide neurokinin A is also shown to be hydrolysed by pig kidney endopeptidase-24.11. The identified products indicated hydrolysis at two sites, Ser5-Phe6 and Gly8-Leu9, consistent with the known specificity of the enzyme. The pattern of hydrolysis of neurokinin A by synaptic membranes prepared from pig striatum was similar to that observed with purified endopeptidase-24.11, and hydrolysis was substantially abolished by the selective inhibitor phosphoramidon. Peptidyl dipeptidase A purified from pig kidney was shown to hydrolyse substance P but not neurokinin A. It is concluded that endopeptidase-24.11 has the general capacity to hydrolyse and inactivate the family of tachykinin peptides, including substance P and neurokinin A.
2

Badiani, K., and G. Arthur. "2-acyl-sn-glycero-3-phosphoethanolamine lysophospholipase A2 activity in guinea-pig heart microsomes." Biochemical Journal 275, no. 2 (April 15, 1991): 393–98. http://dx.doi.org/10.1042/bj2750393.

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We have recently described a lysophospholipase A2 activity in guinea-pig heart microsomes that hydrolyses 2-acyl-sn-glycero-3-phosphocholine (2-acyl-GPC). The presence of a similar activity that hydrolyses 2-acyl-sn-glycero-3-phosphoethanolamine (2-acyl-GPE) was not known. In this study, a lysophospholipase A2 activity in guinea-pig heart microsomes that hydrolyses 2-acyl-GPE has been characterized. The enzyme did not require Ca2+ for activity and exhibited a high specificity for 2-arachidonoyl-GPE and 2-linoleoyl-GPE over 2-oleoyl-GPE and 2-palmitoyl-GPE. The specificity for these unsaturated substrates was observed in the presence and absence of detergents. Selective hydrolysis of 2-arachidonoyl-GPE over 2-palmitoyl-GPE was observed when equimolar quantities of the two substrates were incubated with the enzyme. There was no preferential hydrolysis of either 2-linoleoyl- or 2-arachidonoyl-GPE when presented individually or as a mixture. Significant differences in the characteristics of 2-acyl-GPE-hydrolysing and 2-acyl-GPC-hydrolysing activities included differences in their optimum pH, the effect of Ca2+ and their acyl specificities. Taken together, these results suggest that the two activities are catalysed by different enzymes. 2-Acyl-GPE lysophospholipase activity with a preference for 2-arachidonoyl-GPE over 2-oleoyl-GPE was observed in guinea-pig brain, liver, kidney and lung microsomes. Lysophospholipase A1 activity that catalyses the hydrolysis of 1-acyl-GPE was also present in guinea-pig heart microsomes and had different characteristics from the 2-acyl-GPE-hydrolysing activity, including a preference for saturated over unsaturated substrates. The 2-acyl-GPE lysophospholipase A2 activity appeared to be distinct from Ca(2+)-independent phospholipase A2. The characteristics of the 2-acyl-GPE lysophospholipase A2 suggest it could play a role in the selective release of arachidonic and linoleic acids for further metabolism in cells.
3

Lisak Jakopović, Katarina, Seronei Chelulei Cheison, Ulrich Kulozik, and Rajka Božanić. "Comparison of selective hydrolysis of α-lactalbumin by acid Protease A and Protease M as alternative to pepsin: potential for β-lactoglobulin purification in whey proteins." Journal of Dairy Research 86, no. 1 (February 2019): 114–19. http://dx.doi.org/10.1017/s0022029919000086.

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AbstractThe experiments reported in this research paper examine the potential of digestion using acidic enzymes Protease A and Protease M to selectively hydrolyse α-lactalbumin (α-La) whilst leaving β-lactoglobulin (β-Lg) relatively intact. Both enzymes were compared with pepsin hydrolysis since its selectivity to different whey proteins is known. Analysis of the hydrolysis environment showed that the pH and temperature play a significant role in determining the best conditions for achievement of hydrolysis, irrespective of which enzyme was used. Whey protein isolate (WPI) was hydrolysed using pepsin, Acid Protease A and Protease M by randomized hydrolysis conditions. Reversed-phase high performance liquid chromatography was used to analyse residual proteins. Regarding enzyme selectivity under various milieu conditions, all three enzymes showed similarities in the reaction progress and their potential for β-Lg isolation.
4

Shipilov, A. I., L. A. Kolpashchikova, and S. M. Igumnov. "Selective Hydrolysis of Pentafluorobenzotrichloride." Russian Journal of Organic Chemistry 39, no. 7 (July 2003): 975–78. http://dx.doi.org/10.1023/b:rujo.0000003188.49417.22.

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Chan, Lai Chun, Brian G. Cox, and Rhona S. Sinclair. "Selective Hydrolysis of Methanesulfonate Esters." Organic Process Research & Development 12, no. 2 (March 2008): 213–17. http://dx.doi.org/10.1021/op700226s.

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6

Basavaiah, D., and S. Bhaskar Raju. "Selective Enzymatic Hydrolysis of Phenolic Acetates." Synthetic Communications 24, no. 4 (February 1994): 467–73. http://dx.doi.org/10.1080/00397919408011496.

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7

Blay, Gonzalo, M. Luz Cardona, M. Begoña Garcia, and José R. Pedro. "A Selective Hydrolysis of Aryl Acetates." Synthesis 1989, no. 06 (1989): 438–39. http://dx.doi.org/10.1055/s-1989-27277.

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Litt, M. H., and C. S. Lin. "Selective hydrolysis of oxazoline block copolymers." Journal of Polymer Science Part A: Polymer Chemistry 30, no. 5 (April 1992): 779–86. http://dx.doi.org/10.1002/pola.1992.080300507.

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9

Unnikrishnan, Parvathy, Binsi Puthenveetil Kizhakkethil, Jeyakumari Annamalai, Joshy Chalil George, Aliyamveetil Abubacker Zynudheen, George Ninan, and Chandragiri Nagarajarao Ravishankar. "Selective Extraction of Surface-active and Antioxidant Hydrolysates from Yellowfin Tuna Red Meat Protein using Papain by Response Surface Methodology." Indian Journal of Nutrition and Dietetics 56, no. 1 (January 22, 2019): 10. http://dx.doi.org/10.21048//ijnd.2019.56.1.22125.

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The present study was focused on the selective extraction of surface-active and antioxidant hydrolysates from yellowfin tuna (Thunnus albacares) red meat based on separate hydrolytic conditions using papain. The effect of key processing variables viz., enzymesubstrate ratio (0.25-1.5 %) and hydrolysis time (30-240 min) under optimized temperature and pH, on the protein recovery, surface-active and antioxidative properties, was determined using Response Surface Methodology (RSM) with a central composite design. Single and combined effects of the variables on the responses were studied by formulating 13 experimental runs. The coefficient of determination (R2) ranged between 0.73 – 0.99 indicating the suitability of the fitted regression models. The optimum hydrolytic conditions to get hydrolysates having superior surface-active properties were enzyme-substrate ratio (E/S) of 0.41 % and 30 minutes hydrolysis time with a desirability of 0.611. Similarly, the optimum conditions to exhibit the highest antioxidative properties with a desirability of 0.932 were: 1.28 % E/S and 240 minutes hydrolysis time.
10

Shi, Qixun, Matthew P. Mower, Donna G. Blackmond, and Julius Rebek. "Water-soluble cavitands promote hydrolyses of long-chain diesters." Proceedings of the National Academy of Sciences 113, no. 33 (August 1, 2016): 9199–203. http://dx.doi.org/10.1073/pnas.1610006113.

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Water-soluble, deep cavitands serve as chaperones of long-chain diesters for their selective hydrolysis in aqueous solution. The cavitands bind the diesters in rapidly exchanging, folded J-shape conformations that bury the hydrocarbon chain and expose each ester group in turn to the aqueous medium. The acid hydrolyses in the presence of the cavitand result in enhanced yields of monoacid monoester products. Product distributions indicate a two- to fourfold relative decrease in the hydrolysis rate constant of the second ester caused by the confined space in the cavitand. The rate constant for the first acid hydrolysis step is enhanced approximately 10-fold in the presence of the cavitand, compared with control reactions of the molecules in bulk solution. Hydrolysis under basic conditions (saponification) with the cavitand gave >90% yields of the corresponding monoesters. Under basic conditions the cavitand complex of the monoanion precipitates from solution and prevents further reaction.
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Journal articles Dissertations / Theses

Dissertations / Theses on the topic "Selective Hydrolysis":

1

Adhamy, Asghar. "Selective hydrolysis of lipids using lipases." Thesis, Teesside University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328090.

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Höst, Gunnar. "Engineering carbonic anhydrase for highly selective ester hydrolysis." Doctoral thesis, Linköpings universitet, Molekylär Bioteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10477.

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I denna avhandling presenteras arbete utfört med enzymet humant karboanhydras II (HCAII). Enzymer är en typ av proteiner som accelererar (katalyserar) kemiska reaktioner, vilket är nödvändigt för allt levande. Den naturliga funktionen för HCAII är att katalysera omvandlingen av gasen koldioxid till vätekarbonat, som är löslig i vätska. Detta är viktigt bl.a. för att koldioxid som bildas i kroppen, och fraktas i blodet i form av vätekarbonat, skall hinna över till utandningsluften under den korta tid blodet är i lungorna. Proteiner består av aminosyror som länkats samman i en lång kedja, där varje aminosyra är en av de 20 naturliga aminosyratyperna. Ett proteins struktur och egenskaper bestäms av aminosyrasekvensen, som i sin tur bestäms av genen för just det proteinet. Med genteknik kan ett proteins gen ändras (muteras), så att aminosyrasekvensen ändras, och det har här utnyttjats för att förändra HCAIIs katalytiska egenskaper. Förutom dess naturliga funktion kan HCAII även klyva (hydrolysera) vissa estrar. Mutationer gjordes så att en ’ficka’ i HCAIIs struktur, där molekylerna (substraten) som skall klyvas binder, fick en större volym. På så sätt skapades varianter med en kraftigt ökad kapacitet för att hydrolysera långa estersubstrat jämfört med icke-muterat HCAII. Som en utveckling av detta projekt skapades en mutant av HCAII, som kan hydrolysera ett än mer skrymmande substrat. I ett annat projekt har en ny katalytisk aktivitet skapats i HCAII, som inte utnyttjar enzymets naturliga katalytiska förmåga. Ett nytt estersubstrat konstruerades, med en del som binder kraftigt till HCAII, så att en stark substratbindning erhölls. Sedan muterades vissa aminosyror till en reaktiv aminosyra som heter histidin. Valet av positioner för mutation baserades på en datormodell av enzymet med bundet substrat. Eftersom histidin kan delta i hydrolysreaktioner, får det muterade enzymet möjlighet att klyva substratet. Flera olika mutanter testades, och den effektivaste innehöll ett nära kopplat par av histidiner. Denna mutant undersöktes mer noggrannt, vilket gav viss information om den katalytiska mekanismen. Det långsiktiga målet med detta arbete är att konstruera muterade enzymer som kan klyva giftiga ämnen, eller användas vid framställning av kemikalier. Det finns behov av nya enzymer för olika typer av substrat, och att med rationella metoder skapa nya katalytiska aktiviteter i proteiner är ett svårt vetenskapligt problem som ännu är i ett tidigt utvecklingsskede.
The main part of this thesis describes results from protein engineering experiments, in which the catalytic activity of the enzyme human carbonic anhydrase II (HCAII) is engineered by mutagenesis. This enzyme, which catalyzes the interconversion between CO2 and HCO3- in the body, also has the ability to hydrolyze ester bonds. In one project, the specificity of HCAII towards a panel of para-nitrophenyl ester substrates, with acyl chain lengths ranging from one to five carbon atoms, was changed by enlarging the substrate binding hydrophobic pocket. A variant was identified that has highly increased specificity towards substrates with long acyl chains. The mutant V121A/V143A hydrolyzes pNPV, which has four carbon atoms in the acyl chain, with an efficiency that is increased by a factor of 3000 compared to HCAII. Further, transition state analogues (TSAs) were docked to HCAII and mutant variants, and the results were correlated to the results from kinetic measurements. This indicated that automated docking could be used to some extent to construct HCAII variants with a designed specificity. Using this approach, a HCAII mutant that can hydrolyze a model benzoate ester was created. Interestingly, the resulting variant V121A/V143A/T200A was found to be highly active with other ester substrates as well. For pNPA, a kcat/KM of 1*105 M-1s-1 was achieved, which is the highest efficiency for hydrolysis of carboxylic acid esters reported for any HCAII variant. In another project, the strong affinity between the active site zinc ion and sulfonamide was used to achieve binding of a designed substrate. Thus, the natural Zn-OH- site of HCAII was not used for catalysis, but for substrate binding. The substrate contains a benzenesulfonamide part in one end, with a para-nitrophenyl ester connected via a linker. The linker was chosen to ensure that the scissile bond is positioned close to His-64 and histidine residues introduced by mutagenesis in other positions. Using this approach, an enzyme was designed with a distinctly new two-histidine catalytic site for ester hydrolysis. The mutant, F131H/V135H, has a kcat/KM of approximately 14000 M-1s-1, which corresponds to a rate enhancement of 107 compared to a histidine mimic. Finally, results are reported on a project aimed at cloning and producing a putative carbonic anhydrase from the malaria parasite Plasmodium falciparum. The gene was cloned by PCR and the construct was overexpressed in E. coli. However, the resulting protein was not soluble, and initial attempts to refold it are also reported.
3

Osei-Mensah, Marian. "Synthesis of Resveratrol Ester Derivatives Using Selective Enzymatic Hydrolysis." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etd/1400.

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Resveratrol, a naturally derived stilbene, is an interesting compound mostly talked about recently because for its anti-cancer properties. Unfortunately it has some shortcomings due to its low bioavailability and low solubility in water. For this reason, my research is to overcome resveratrol's drawbacks by improving its bioavailability and hydrophilicity. My research is focused on syntheses of novel derivatives of resveratrol such as 3, 5-di-O-isobutyroyl resveratrol and 3, 5-di-O-hexanoyl resveratrol using lipase catalyzed hydrolysis. Therefore, the tri-acylated resveratrols 3, 5, 4'-tri-O-isobutyroyl resveratrol and 3, 5,4'-tri-O-hexanoyl resveratrol were first synthesized. 3,5,4'-tri-O-isobutyroyl resveratrol and 3,5,4'-tri-O-hexanoyl resveratrol were then hydrolyzed using lipase (C. Antarctica) to obtain the products 3,5-di-O-isobutyroyl resveratrol and 3,5-di-O-hexanoyl resveratrol. The four compounds 3,5-di-O-isobutyroyl resveratrol, 3,5-di-O-hexanoyl resveratrol, 3,5,4'-tri-O-hexanoyl resveratrol, and 3,5-di-O-hexanoyl resveratrol were characterized by 1H NMR and 13C NMR.
4

Lombardi, Erica. "Selective photo-oxidation of cellobiose with tio2-supported metal nanoparticles." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6017/.

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Upgrade of biomass to valuable chemicals is a central topic in modern research due to the high availability and low price of this feedstock. For the difficulties in biomass treatment, different pathways are still under investigation. A promising way is in the photodegradation, because it can lead to greener transformation processes with the use of solar light as a renewable resource. The aim of my work was the research of a photocatalyst for the hydrolysis of cellobiose under visible irradiation. Cellobiose was selected because it is a model molecule for biomass depolymerisation studies. Different titania crystalline structures were studied to find the most active phase. Furthermore, to enhance the absorption of this semiconductor in the visible range, noble metal nanoparticles were immobilized on titania. Gold and silver were chosen because they present a Surface Plasmon Resonance band and they are active metals in several photocatalytic reactions. The immobilized catalysts were synthesized following different methods to optimize the synthetic steps and to achieve better performances. For the same purpose the alloying effect between gold and silver nanoparticles was examined.
5

Fanutti, Cristina. "The selective hydrolysis of tamarind seed xyloglucan (tamarind gum) using enzymes isolated from germinated nasturtium (Tropaeolum majus L.) cotyledons." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386556.

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6

Desai, S. B. "Lipases in biotransformations: resolution of some novel alcohol and diol substrates via selective hydrolysis of their esters and related mechanistic." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2000. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2275.

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Chapman, Jamie M. "CARBOXYL ESTER LIPASE (CEL) IS A MAJOR ENZYME RESPONSIBLE FOR THE HYDROLYSIS OF CHOLESTERYL ESTERS IN THE SELECTIVE UPTAKE PATHWAY OF THE LIVER." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin970245752.

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8

Stoffregen, Stacey Anne. "Palladium(II) and platinum(II) synthetic peptidases residue- and sequence-selective hydrolysis and the photochemistry of sulfoxides, S,C-sulfonium ylides, and sulfilimines: unimolecular bond cleavage/." [Ames, Iowa : Iowa State University], 2007.

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9

Nouveau, Thibaut. "Nébulisation de nouveaux polyplexes pour le transfert de gènes." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS734.pdf.

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La thérapie génique est une forme de thérapie pour traiter les maladies génétiques héréditaires ou acquises tels que les cancers ou la mucoviscidose. L’introduction d’un polynucléotide, par voie systémique ou locale (orale ou nasale par exemple), au sein des cellules malades permet de corriger les défauts à l’origine des mutations génétiques. Néanmoins, le franchissement des différentes barrières biologiques nécessaire à l’internalisation de l’ADN ne peut se faire que par l’intermédiaire d’un vecteur qui va le protéger et lui permettre d’atteindre le noyau de la cellule où il sera transcrit. Divers vecteurs (viraux ou synthétiques) ont vu le jour, tels que des vecteurs polymères cationiques à base de PEI. Cependant, bien qu’efficaces, ces vecteurs sont immunogènes à forte dose. Des fonctionnalisations pour réduire cette toxicité, telle que la PEGylation, ont été mises au point et permettent de renforcer les vecteurs en apportant de la furtivité aux polyplexes finaux. Cependant, ces stratégies montrent des limites nécessitant la synthèse de nouveaux types de polymères. La POxylation représente une bonne alternative à l’utilisation du PEG pour former de nouveaux polyplexes par l’ajout d’un bloc formé d’une ou plusieurs poly(2-alkyl-2-oxazoline)s. Les copolymères sont synthétisés par hydrolyse sélective d’un copolymère triblocs PEtOx-b-PnPrOx-b-PMeOx en utilisant les propriétés thermosensibles des blocs hydrophobes et un sel kosmotrope afin de former des systèmes cœur-couronne permettant l’hydrolyse du bloc PMeOx en PEI. Les systèmes ont ensuite été formulés selon une formulation standard et une méthode par « micro-extrusion ». Les polyplexes ont ensuite été utilisés in vitro par déposition ou par une méthode de nébulisation, idéale pour le traitement de maladies pulmonaires. De très bons résultats de transfection ont été obtenus, résultats qui dépendent de différents paramètres (Mn, PEI, architecture polymère, rapport de charge +/-)
Gene therapy is a form of therapy used to treat hereditary or acquired genetic diseases such as cancer or cystic fibrosis. Introducing a polynucleotide into diseased cells, either via the systmeic route or the local route (oral or nasal inhalation), corrects the defects causing the genetic mutations. However, DNA can only be internalized using a vector that protects it and enables it to reach the cell nucleus, where it will be transcribed. Various vectors (viral or synthetic) have been developed, such as PEI-based cationic polymer vectors. However, although effective, these PEI-based vectors are immunogenic at high doses. Functionalizations to reduce this toxicity, such as PEGylation, have been developed, making it possible to reinforce vectors by adding stealthiness to the final polyplexes. However, these strategies have their limitations, necessitating the synthesis of new types of polymer. POxylation represents a good alternative to PEG usage to form new polyplexes by adding a block formed from one or more poly(2-alkyl-2-oxazoline)s. The copolymers are synthesized by selective hydrolysis of a PEtOx-b-PnPrOx-b-PMeOx triblock copolymer using the thermosensitive properties of the hydrophobic blocks and a kosmotropic salt to form core-shell systems enabling hydrolysis of the PMeOx block to PEI. Then, the systems were formulated using a standard formulation and a "micro-extrusion" method. The polyplexes obtained were used in vitro experiments, by deposition or by a nebulization method, ideal for the treatment of pulmonary diseases. Very good transfection results were obtained, depending on various parameters (Mn, PEI, polymer architecture, +/- charge ratio)
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Lu, Fei. "Electrochemically Induced Urea to Ammonia on Ni Based Catalyst." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1502235953529178.

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Books on the topic "Selective Hydrolysis":

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Yartys, Volodymyr, Yuriy Solonin, and Ihor Zavaliy. HYDROGEN BASED ENERGY STORAGE: STATUS AND RECENT DEVELOPMENTS. Institute for Problems in Materials Science, 2021. http://dx.doi.org/10.15407/materials2021.

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The book presents the recent achievements in the use of renewable energy sources, chemical processes, biomaterials for the efficient production of hydrogen, its storage and use as a fuel in the FC-based power systems. Novel results were obtained within two research programs, namely, the NATO Science for Peace G5233 project “Portable Energy Supply” (2017-21) and the priority program of the NAS of Ukraine "Development of scientific principles of the production, storage and use of hydrogen in autonomous energy systems" (2019-21). The priority program was implemented by the leading institutes of the National Academy of Sciences of Ukraine and contained three focus areas: efficient materials and technologies for the production, storage and use of hydrogen. This includes the development of new functional materials for the fuel cells and the application of the latter in autonomous power supply systems. 4-years NATO's project was implemented by a consortium led by the Institute for Energy Technology (Coordinator; NATO country - Norway) together with the institutes from the NATO partner country – Ukraine – belonging to the NAS of Ukraine: Physico-Mechanical Institute, Institute for Problems of Materials Science and Institute of General and Inorganic Chemistry. The work included the studies of H2 generation by the hydrolysis of MgH2, Al and NaBH4, analysis of the mechanisms of these processes and selection of the most efficient catalyzers. The project successfully developed a system integrating hydrolysis process and a PEM fuel cell.

Book chapters on the topic "Selective Hydrolysis":

1

Boeriu, Carmen G., Ivo F. Eggen, Dirk-Jan van Zoelen, and Gilbert H. Bours. "Selective enzymatic hydrolysis of C-terminal tert-butyl esters of peptides." In Advances in Experimental Medicine and Biology, 115–16. New York, NY: Springer New York, 2009. http://dx.doi.org/10.1007/978-0-387-73657-0_51.

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Testillano, P. S., M. C. Risueño, M. A. Ollacarizqueta, and C. J. Tandler. "Selective Staining of DNA at the Ultrastructural Level After Alkaline Hydrolysis." In Nuclear Structure and Function, 477–81. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0667-2_98.

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Smith, Thomas L. "Selective Effects of Ethanol on Neuropeptide — Mediated Polyphosphoinositide Hydrolysis and Calcium Mobilization." In Alcohol, Cell Membranes, and Signal Transduction in Brain, 245–54. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2470-0_22.

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Hanchar, Robert J., Farzaneh Teymouri, Chandra D. Nielson, Darold McCalla, and Mark D. Stowers. "Separation of Glucose and Pentose Sugars by Selective Enzyme Hydrolysis of AFEX-Treated Corn Fiber." In Applied Biochemistry and Biotecnology, 313–25. Totowa, NJ: Humana Press, 2007. http://dx.doi.org/10.1007/978-1-60327-181-3_28.

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Laasch, Henrik, and Jürgen Schumann. "Inhibition of ATP Hydrolysis in Isolated Chloroplasts by Lipophilic Tertiary Amines and the Mechanism of ‘Selective Uncoupling’." In Current Research in Photosynthesis, 2067–70. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0511-5_474.

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Franco, Renan Louro Cardoso, Carsten Eichert, Charlotte Lücking, Lars Biermann, Mandy Paschetag, and Stephan Scholl. "revolPET®: An Innovative “Back-to-Monomer” Recycling Technology for the Open Loop Value Chain of PET and Polyester Composite Packaging and Textiles." In Lecture Notes in Mechanical Engineering, 175–83. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_20.

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AbstractNowadays there is a need for innovative solutions for composite materials in the packaging and textile sectors. These are formed by multilayer structures that improve technical performance however complicates recycling. Consequently, they are mostly sent to energy recovery or downgrade recycling processes. To avoid this, new recycling technologies are needed.The innovative “back-to-monomer” recycling technology “revolPET®” represents a solution for this challenge. In the process, the polyethylene terephthalate (PET) is selectively depolymerized to recover the monomers ethylene glycol (EG) and terephthalic acid (TA) for a new PET production. By an alkaline hydrolysis, the PET reacts continuously with a strong base in a twin-screw extruder. The average residence time in the extruder is less than one minute with a process yield up to 95%. Due to the mild depolymerization conditions, the other polymers remain chemically unchanged and can be easily separated. The produced monomers are regained in virgin quality and can achieve a 33% reduction on the greenhouse gases emissions if compared with the crude oil production route.In this contribution, the technology on a pilot scale as well as the results of the first scale-up investigations are presented and discussed with respect to technical maturity and environmental benefit.
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Mao, Youdong. "Structure, Dynamics and Function of the 26S Proteasome." In Subcellular Biochemistry, 1–151. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58971-4_1.

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AbstractThe 26S proteasome is the most complex ATP-dependent protease machinery, of ~2.5 MDa mass, ubiquitously found in all eukaryotes. It selectively degrades ubiquitin-conjugated proteins and plays fundamentally indispensable roles in regulating almost all major aspects of cellular activities. To serve as the sole terminal “processor” for myriad ubiquitylation pathways, the proteasome evolved exceptional adaptability in dynamically organizing a large network of proteins, including ubiquitin receptors, shuttle factors, deubiquitinases, AAA-ATPase unfoldases, and ubiquitin ligases, to enable substrate selectivity and processing efficiency and to achieve regulation precision of a vast diversity of substrates. The inner working of the 26S proteasome is among the most sophisticated, enigmatic mechanisms of enzyme machinery in eukaryotic cells. Recent breakthroughs in three-dimensional atomic-level visualization of the 26S proteasome dynamics during polyubiquitylated substrate degradation elucidated an extensively detailed picture of its functional mechanisms, owing to progressive methodological advances associated with cryogenic electron microscopy (cryo-EM). Multiple sites of ubiquitin binding in the proteasome revealed a canonical mode of ubiquitin-dependent substrate engagement. The proteasome conformation in the act of substrate deubiquitylation provided insights into how the deubiquitylating activity of RPN11 is enhanced in the holoenzyme and is coupled to substrate translocation. Intriguingly, three principal modes of coordinated ATP hydrolysis in the heterohexameric AAA-ATPase motor were discovered to regulate intermediate functional steps of the proteasome, including ubiquitin-substrate engagement, deubiquitylation, initiation of substrate translocation and processive substrate degradation. The atomic dissection of the innermost working of the 26S proteasome opens up a new era in our understanding of the ubiquitin-proteasome system and has far-reaching implications in health and disease.
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Asano, Y., and P. Kaul. "7.7 Hydrolysis and Reverse Hydrolysis: Selective Nitrile Hydrolysis using Nitrilase and its Related Enzymes." In Comprehensive Chirality, 122–42. Elsevier, 2012. http://dx.doi.org/10.1016/b978-0-08-095167-6.00708-4.

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Procter, Garry. "Hydrolysis and esterification." In Stereoselectivity in Organic Synthesis. Oxford University Press, 1998. http://dx.doi.org/10.1093/hesc/9780198559573.003.0010.

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This chapter focuses on hydrolysis and esterification. Enzymes can be regarded simply as enantioselective catalysts. However, they are much larger and much more complicated than ‘normal’ enantioselective catalysts. In addition, many enzymes are selective about the structure of the substrates which they will accept, but some of them will accept a reasonably wide range of substrates. There are two basic processes which can be carried out by enzyme hydrolysis: resolution of a racemate by kinetic resolution and conversion of a meso-compound into a chiral product. Typically, the meso-compound used as starting material possesses two enantiotopic ester groups, so hydrolysis of one of these will produce enantiomeric products. This is sometimes referred to as ‘asymmetrization’. Careful chemical manipulation of a single enantiomer produced by asymmetrization can give products in either enantiomeric form.
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McKenna, C. E., B. A. Kashemirov, and K. M. Błażewska. "Selective Hydrolysis of Triesters of Phosphoric Acid." In Organophosphorus Compounds (incl. RO-P and RN-P), 1. Georg Thieme Verlag KG, 2009. http://dx.doi.org/10.1055/sos-sd-042-00966.

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Conference papers on the topic "Selective Hydrolysis":

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Cairns, Amy J., Rajesh K. Saini, and Fakuen F. Chang. "Hydrolysis-Promoted Polymerization of Furfuryl Alcohol: Selective Method for Mitigating Excess Water Production in Oil Wells." In Middle East Oil, Gas and Geosciences Show. SPE, 2023. http://dx.doi.org/10.2118/213440-ms.

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Abstract Water production during hydrocarbon extraction is a major problem for the upstream oil and gas industry. The challenge posed for operators is the increase in operational costs pertaining to separation, treatment, and disposal processes, amongst others. A wide assortment of scenarios can lead to unwanted water production from wells in hydrocarbon producing zones such as casing leaks, cusping, water breakthrough due to the presence of natural fractures or high permeability streaks, etc. Methods of treatment are not a one-size-fits-all approach but range from being simple to more complex. To best mitigate the problem, particularly in the long-term, it is necessary to perform a thorough evaluation to understand the location and cause of the water production. Key existing solutions use mechanical devices, chemical methods, or combinations thereof to form a semi-to-impermeable barrier to prevent the flow of water from reaching the wellbore. While potentially very effective, the longevity of such methods is hindered by lack of efficiency, selectivity, stability, high cost and placement risks in relation to the completion type. Here, we report on the development, formulation, and performance evaluation of a robust thermoset resin system that is inherently selective for blocking water -bearing zones in oil producing formations. The strategy behind this approach is based on acid-catalyzed polymerization of furfuryl alcohol. Specifically, use of judiciously selected acid-generating precursors, namely ester-containing compounds that are hydrophobic in nature. Under suitable reaction conditions, hydrolysis takes place at the interfacial boundary thereby releasing acid and directing blockage specifically to the water zone via resin formation. The resin system has been formulated for application in carbonate or sandstone reservoirs with temperatures up to 150 ˚C and set times up to 48 h. In this study, an overview of our down-selection process for ester selection guided by static bottle test results and regained permeability data obtained under reservoir conditions using a coreflood apparatus will be discussed. This chemical method for mitigating excess water production in oil wells is configured to selectively plug the water producing zones without affecting the oil producing zone. Instead, it is proposed that suitable chemical placement can be achieved by bullheading the treatment into the formation thereby reducing operational complexity and cost.
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Bebbington, J. A., G. Barbarossa, J. R. Bonar, and J. S. Aitchison. "Rare-earth-doped silica waveguides fabricated by flame hydrolysis deposition and aerosol doping." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/oam.1992.tuj4.

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We have fabricated rare-earth-doped SiO2-P2O5 planar films on silicon substrate by using flame hydrolysis deposition, incorporating the rare-earth ions by an aerosol doping technique, for the first time to our knowledge. Rare-earth-doping levels in the glass were dependant on the nebulized solution strength and the delivery rate of the aerosol to the torch. The aerosol doping technique has the advantage over solution doping of directly incorporating the rare-earth ions into the soot during the deposition and giving control of the doping profile through the film by contolling the transfer of the aerosol to the torch during the deposition. The aerosol doping technique is described, as well as the fabrication and optical assessment of channel waveguides with a view to realizing waveguide lasers. Moreover, the long term goal is to accomplish mono­lithic integration of active and passive optical components. This may be achieved by selective area doping of planar films. The method of selective area doping is discussed for aerosol doping.
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Kamasaka, Hiroshi, Kazuhisa Sugimoto, Hiroki Takata, Takahisa Nishimura, and Takashi Kuriki. "SELECTIVE HYDROLYSIS OF AMYLOSE IN THE PRESENCE OF AMYLOPECTIN BY A UNIQUE ALPHA-AMYLASE FAMILY ENZYME." In XXIst International Carbohydrate Symposium 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.788.

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Habchi, Chaouki, Shaoping Quan, Scott Drennan, and Julien Bohbot. "Towards Quantitative Prediction of Urea Thermo-Hydrolysis and Deposits Formation in Exhaust Selective Catalytic Reduction (SCR) Systems." In WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2019. http://dx.doi.org/10.4271/2019-01-0992.

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Johe, Katrin, and Thomas Sattelmayer. "Modelling Approach for a Hydrolysis Reactor for the Ammonia Production in Maritime SCR Applications." In ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3537.

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The catalytic generation of ammonia from a liquid urea solution is a critical process determining the performance of SCR (Selective Catalytic Reduction) systems. Solid deposits on the catalyst surface from the decomposition of urea have to be avoided, as this leads to reduced system performance or even failure. At present, reactor design is often empirical, which poses a risk for costly iterations due to insufficient system performance. The presented research project proposed a performance prediction and modelling approach for SCR hydrolysis reactors generating ammonia from urea. Different configurations of hydrolysis reactors were investigated experimentally. Ammonia concentration measurements provided information about parameters influencing the decomposition of urea and the system performance. The evaporation of urea between injection and interaction with the catalyst was identified as the critical process driving the susceptibility to deposit formation. The spray of urea solution was characterised in terms of velocity distribution by means of particle-image velocimetry. Results were compared with theoretical predictions and calculation options for processes in the reactor were determined. Numerical simulation was used as an additional design and optimisation tool of the proposed model. The modelling approach is presented by a step-by-step method which takes into account design constraints and operating conditions for hydrolysis reactors.
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Lee, Yu Jin, Changhwan Ju, and In-Hwan Kim. "Novel Strategy for Synthesis of Stearidonic Acid Enriched Triacylglycerol from Ahiflower Seed Oil via a Two-step Enzyme Reaction." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/uhjd7801.

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Stearidonic acid (SDA) is a plant-based n-3 polyunsaturated fatty acids (PUFAs) with several positive therapeutic effects on human health such as reducing risks of cardiovascular diseases, obesity, inflammation, and cancer. Moreover, the conversion efficiency of SDA to EPA is significantly higher than α-linolenic acid to EPA, in the human body. Plant oils with SDA, such as ahiflower seed oil and echium seed oil, exhibit substantially higher oxidative stability than fish oil with EPA and DHA, the most popular n-3 PUFA. The present study has successfully carried out the enrichment of SDA and the synthesis of triacylglycerol (TAG) consecutively via two lipase-catalyzed reactions, which are selective hydrolysis and esterification, while most of n-3 PUFAs studies have separately employed its enrichment and the synthesis of TAG. SDA was enriched into a glyceride fraction from ahiflower seed oil by Candida rugosa lipase-catalyzed selective hydrolysis, and the SDA-enriched glycerides were separated from the reaction mixture using molecular distillation. SDA was enriched up to 40.7 mol% in glyceride fraction from an initial value of 21.6 mol% under the optimum conditions of 35 oC, and 0.1% enzyme loading relative to the weight of the total substrate. Then, SDA-enriched TAG was synthesized from the SDA-enriched glycerides and the fatty acid obtained from part of the SDA-enriched glycerides by saponification via esterification using an in-house immobilized lipase as a biocatalyst. The in-house immobilized lipase was prepared from Eversa® Transform 2.0 (liquid form) using Lewatit VP OC 1600 as a carrier. The maximum TAG yield of ca. 94% was achieved after 12 h under the optimum conditions, which are the temperature of 50 oC, the enzyme loading of 10 % relative to the weight of the total substrate, and the vacuum of 10 torr."
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Han, Jin-Ye, Gui-Hua Zhang, Yan Wang, Jin-Quan Wan, Ze-Yu Guan, Yong-Wen Ma, and Zi-Min Liu. "Influence of Strong Electronegativity Groups -Cl as the Adsorption Center of PTA@MIL-101-NH²-Cl for the Selective Hydrolysis of Cellulose into Glucose." In 3rd 2017 International Conference on Sustainable Development (ICSD 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/icsd-17.2017.4.

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Kaugarenia, Nastassia, Sophie Beaubier, Erwann Durand, François Lesage, Xavier Framboisier, Arnaud Aymes, Pierre Villeneuve, and Romain Kapel. "Optimization of Potent Mineral Chelating Peptides Production from Rapeseed Meal Proteins Proteolysis and Peptide Characterizations." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ougk6662.

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Preventing lipid oxidation and microbial spoilage are both major concerns in sectors such as food and cosmetic industries. Biopeptides, arouse great interest to substitute synthetic antioxidants. Some plant proteins, like 2S rapeseed albumins are known presenting antimicrobial properties. In this context, we aimed to valorize total rapeseed meal proteins with controlled enzymatic proteolysis to generate mineral chelating peptides from the 11S globulins fraction while keeping intact the albumins fraction. To do so, screening of proteases on total rapeseed protein isolate was implemented highlighting a globulin-selective hydrolysis with Prolyve®. Ultrafiltration was then used to purified albumins and enrich the peptide fraction. The fraction obtained showed a noteworthy metal chelating activity. Then, the selected proteolysis was optimized in order to maximize the albumins purity and yield. For that, enzymatic mechanism identification in a wide operating conditions area was led to define the DoE. Then, simulation of hydrolysis kinetics was driven to predict protein fractions concentration at any time and any set of operation conditions. The obtained models were implemented in a genetic-evolutionary algorithm to generate the Pareto Front and Domain, presenting the targeted economical compromises. One solution was chosen and the identified corresponding operating conditions proved the metal chelating activity conservation (EC50 = 247 ± 27 µg) for three times faster production at the same enzyme cost. Finally, peptide activity was investigated in oil-in-water emulsion systems and compared with EDTA. Results showed that peptides could be as effective as EDTA to avoid primary and secondary lipid oxidation products formation.This work demonstrates an original total valorization of both rapeseed meal proteins in food applications. First, antioxidant peptides produced from the globulin fraction, could be used as food preservative in oil-in-water emulsion systems, but also as preventing agents for micronutrient deficiencies. And, the purified albumin fraction could be used to prevent microbial spoilage.
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Fujita, Natsuki, Hitoshi Mimura, Takaaki Kobayashi, Kazuyuki Sekino, and Kunitaka Nagamine. "Separation of Nuclides by Different Types of Zeolites in the Presence of Boric Acid." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30193.

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The development of selective adsorbents has become very important for the effective multi-nuclide decontamination. In this study, the selective adsorption properties of 26 nuclides for different types of zeolites (A, L, natural mordenite (NM), Ag-NM) were examined in the presence of boric acid. The batch adsorption experiments were carried out using four kinds of test solutions containing boric acid and calcium hydroxide; (1)DW (distilled water) + H3BO4: 3,000 ppm + LiOH: 10 ppb, (2)DW + Ca(OH)2: 500 ppm + H3BO4: 3,000 ppm + LiOH: 10 ppb, (3)Seawater (30% diluted) + H3BO4: 3,000 ppm, (4)Seawater + H3BO4: 3,000ppm. The uptake (%) of Sr2+ for zeolite A (A-51J), Cs+ for natural mordenite (NM, 2460#, Ayashi, Sendai), and I− for Ag-NM was determined under the following conditions; Concentration of Sr2+, Cs+ and I− ions: 10 ppm, V/m = 100 cm3/g, 25°C, 24 h. The uptake (%) of Sr2+, Cs+ and I− ions was estimated to be above 90%, while tended to decrease in the presence of seawater. Especially, the uptake (%) of I− ions for Ag-NM markedly decreased in the presence of seawater. As for the zeolites A and L, the uptake (%) of 26 elements was determined by using two kinds of test solutions; (1)DW (distilled water) + H3BO4: 3,000 ppm + LiOH: 10 ppb + 26 nuclides: 10 ppm, (2)Seawater (30% diluted) + H3BO4: 3,000 ppm + 26 nuclides: 10 ppm. Zeolite A has relatively large uptake percentage for Sr, Co, Ni and Zn, and zeolite L has high adsorbability to lanthanoid group of Eu, Ce and Pr. The increase in pH led to the enhancement of uptake (%), while the hydrolysis of metal ions should be also considered. The multi-nuclides separation is thus expected by considering the difference in uptake properties of zeolite A, L and natural mordenite.
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Bandhu, Sheetal, and Debashish Ghosh. "Genetic modification to enhance single cell oil production in the oleagineous yeast Rhodotorula mucilaginosa." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/bdpk2930.

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Liquid fuels derived from non-fossil resources are considered feasible alternatives as global fuel demand rises. Yeast single cell oil is gaining ground as feedstock for biofuels and oleochemicals over plant-borne or algal oil due to its short lifespan and invariable quality under different seasonal or geographical conditions. In the present work, oleaginous yeast Rhodotorula mucilaginosa IIPL32 was genetically modified to improve its oil-producing capacity by overexpressing malic enzyme, a reductant providing enzyme active in several oleaginous yeasts. Intracellular Malic enzyme was purified and characterized to validate its presence and determine its involvement in lipid synthesis and NADPH+ supply in the yeast R mucilaginosa. Apart from the pentose phosphate route, it was found that malic enzymes also provided reductants for lipid biosynthesis in this yeast. A linear expression cassette was created for selective integration of the malic enzyme under a strong promoter into the yeast genome. The lipid output was increased 1.18-fold along with significant alteration in its fatty acid profile. Estimating fuel properties revealed that the total monounsaturated fatty acids improved from 49% to 66%. The lipid produced by transformed yeast complies with fuel properties (Density, Viscosity, Cetane number, Cloud point, Pour point) as per the EU, Indian, and US standards. We conclude that genetically modified yeast lipids could be a sustainable alternative to using plant-borne oil in biofuel generation. The yeast's ability to assimilate pentose sugars generated from biomass hydrolysis makes it an efficient oil platform.

Reports on the topic "Selective Hydrolysis":

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Mevarech, Moshe, Jeremy Bruenn, and Yigal Koltin. Virus Encoded Toxin of the Corn Smut Ustilago Maydis - Isolation of Receptors and Mapping Functional Domains. United States Department of Agriculture, September 1995. http://dx.doi.org/10.32747/1995.7613022.bard.

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Ustilago maydis is a fungal pathogen of maize. Some strains of U. maydis encode secreted polypeptide toxins capable of killing other susceptible strains of U. maydis. Resistance to the toxins is conferred by recessive nuclear genes. The toxins are encoded by genomic segments of resident double-strande RNA viruses. The best characterized toxin, KP6, is composed of two polypeptides, a and b, which are not covalently linked. It is encoded by P6M2 dsRNA, which has been cloned, sequenced and expressed in a variety of systems. In this study we have shown that the toxin acts on the membranes of sensitive cells and that both polypeptides are required for toxin activity. The toxin has been shown to function by creating new pores in the cell membrane and disrupting ion fluxes. The experiments performed on artificial phospholipid bilayers indicated that KP6 forms large voltage-independent, cation-selective channels. Experiments leading to the resolution of structure-function relationship of the toxin by in vitro analysis have been initiated. During the course of this research the collaboration also yielded X-ray diffracion data of the crystallized a polypeptide. The effect of the toxin on the pathogen has been shown to be receptor-mediated. A potential receptor protein, identified in membrane fractions of sensitive cells, was subjected to tryptic hydrolysis followed by amino-acid analysis. The peptides obtained were used to isolate a cDNA fragment by reverse PCR, which showed 30% sequence homology to the human HLA protein. Analysis of other toxins secreted by U. maydis, KP1 and KP4, have demonstrated that, unlike KP6, they are composed of a single polypeptide. Finally, KP6 has been expressed in transgenic tobacco plants, indicating that accurate processing by Kex2p-like activity occurs in plants as well. Using tobacco as a model system, we determined that active antifungal toxins can be synthesized and targeted to the outside of transgenic plant cells. If this methodology can be applied to other agronomically crop species, then U. maydis toxins may provide a novel means for biological control of pathogenic fungi.

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