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Sample records for food-grade enzyme preparation

  1. Identification of food-grade subtilisins as gluten-degrading enzymes to treat celiac disease

    Science.gov (United States)

    Wei, Guoxian; Tian, Na; Siezen, Roland; Schuppan, Detlef

    2016-01-01

    Gluten are proline- and glutamine-rich proteins present in wheat, barley, and rye and contain the immunogenic sequences that drive celiac disease (CD). Rothia mucilaginosa, an oral microbial colonizer, can cleave these gluten epitopes. The aim was to isolate and identify the enzymes and evaluate their potential as novel enzyme therapeutics for CD. The membrane-associated R. mucilaginosa proteins were extracted and separated by DEAE chromatography. Enzyme activities were monitored with paranitroanilide-derivatized and fluorescence resonance energy transfer (FRET) peptide substrates, and by gliadin zymography. Epitope elimination was determined in R5 and G12 ELISAs. The gliadin-degrading Rothia enzymes were identified by LC-ESI-MS/MS as hypothetical proteins ROTMU0001_0241 (C6R5V9_9MICC), ROTMU0001_0243 (C6R5W1_9MICC), and ROTMU0001_240 (C6R5V8_9MICC). A search with the Basic Local Alignment Search Tool revealed that these are subtilisin-like serine proteases belonging to the peptidase S8 family. Alignment of the major Rothia subtilisins indicated that all contain the catalytic triad with Asp (D), His (H), and Ser (S) in the D-H-S order. They cleaved succinyl-Ala-Ala-Pro-Phe-paranitroanilide, a substrate for subtilisin with Pro in the P2 position, as in Tyr-Pro-Gln and Leu-Pro-Tyr in gluten, which are also cleaved. Consistently, FRET substrates of gliadin immunogenic epitopes comprising Xaa-Pro-Xaa motives were rapidly hydrolyzed. The Rothia subtilisins and two subtilisins from Bacillus licheniformis, subtilisin A and the food-grade Nattokinase, efficiently degraded the immunogenic gliadin-derived 33-mer peptide and the immunodominant epitopes recognized by the R5 and G12 antibodies. This study identified Rothia and food-grade Bacillus subtilisins as promising new candidates for enzyme therapeutics in CD. PMID:27469368

  2. Proteomic analysis and food-grade enzymes of Moringa oleifer Lam. a Lam. flower.

    Science.gov (United States)

    Shi, Yanan; Wang, Xuefeng; Huang, Aixiang

    2018-08-01

    Moringa oleifer Lam. flower contain high-proteins and function nutrients. Many advances have been made to it, but there is still no proteomic information of this species. Total protein from the flowers applied shotgun 2DLC-MS/MS proteomic identified 9443 peptides corresponding to 4004 high-confidence proteins by Proteome Discoverer™ Software 2.1. These proteins were mostly distributed ranging between 40 and 70 kDa. Gene Ontology (GO) analysis indicated that the largest of the proteins were cytoplasm 72.7%, catalytic activity 61.5% and macromolecule metabolism 43.7%, and KEGG analysis revealed that the largest group of 129 proteins was involved in Ribosome to directing protein synthesis (translation). Moreover, a number of commercially important food-grade enzymes were commented, 261 proteins were annotated as carbohydrate-active enzymes, 16 protease, 22 proteins are assigned to the citrate cycle, which the top proteins were assigned to GH family, cysteine synthase and serine/threonine-protein phosphatase. These enzymes indicated that is a new source with potential use for fermentation and brewing industry, fruit and vegetable storage and the development of function peptides. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Bio-processing of Agro-industrial Wastes for Production of Food-grade Enzymes: Progress and Prospects

    Directory of Open Access Journals (Sweden)

    Parmjit S Panesar

    2016-10-01

    Full Text Available Background and Objectives: In the era of global industrialization, enzymes are being used extensively in the various sectors including food processing. Owing to the high price of enzymes, various initiatives have been undertaken by the R&D sector for the development of new processes or improvement in the existing processes for production of cost effective enzymes. With the advancement in the field of biotechnology, different bioprocesses are being used for utilization of different agro-industrial residues for the production of various enzymes. This review focuses on different types of agro-industrial wastes and their utilization in the production of enzymes. The present scenario as well as the future scope of utilization of enzymes in the food industry has also been discussed.Results and Conclusion: The regulations from the various governmental as well as environmental agencies for the demand of cleaner environment have led to the advancement in various technologies for utilization of the wastes for the production of value-added products such as enzymes. Among the different types of fermentation, maximum work has been carried under solid state conditions by batch fermentation. The research has indicated the significant potential of agro-industrial wastes for production of food-grade enzymes in order to improve the economics of the process.Conflict of interests: The authors declare no conflict of interest.

  4. Preparation of high purification and food grade phosphoric acid from technical grade phosphoric acid by liquid-liquid detraction method

    International Nuclear Information System (INIS)

    Alimoradi, M.; Borji, F.; Kishani, A.

    2002-01-01

    Pay attention to increasing consumption of high purification and food grade phosphoric acid in various industries and food industries and on in on hand and lack of preparation between production and distribution of this products its purification is so vital. In this article of liquid-liquid extraction method with normal hexane-mixture of ammonia and acetone-diisopropyl alcohol and normal butanol solvents and these determination of distribution coefficient each one with ph-me try titration we can evaluate effectiveness and sufficiency each one. Because of proper coefficient distribution and its local production of normal butanol solvent and low price is the best solvent. To phosphoric acid modifying coefficient distribution for extraction of phosphoric acid we can add a little value sulfuric acid to the mixture and to remove flouride impurity we add a little Na 2 O. After extraction stage extracted phosphoric acid in the normal strips by evaluating with distilled water and then by passing the carbon active bed and following passes of cationic resine column and concentrated with vacuum distillation. Conclusion of this article is produce of phosphoric acid 85% w/w and food grade from impure phosphoric acid 52% w/w with technical grade

  5. Processing of commercial peanut cake into food-grade meal and its utilization in preparation of cookies.

    Science.gov (United States)

    Tate, P V; Chavan, J K; Patil, P B; Kadam, S S

    1990-04-01

    The commercial cake produced during expeller pressing of peanuts was extracted with n-hexane, and 80% ethanol followed by sieving through 80 mesh, to remove residual oil, pigments, bitter taste and fibrous material. The processed meal exhibited comparable composition with defatted peanut flour prepared in the laboratory by solvent extraction of full-fat peanut meal. However, the processed cake meal exhibited low methionine content and in vitro protein digestibility as compared with defatted peanut flour. The processed cake meal can be blended with wheat flour to the extent of 10% (w/w) to prepare acceptable cookies with improved protein and mineral contents.

  6. Preparation of curcumin microemulsions with food-grade soybean oil/lecithin and their cytotoxicity on the HepG2 cell line.

    Science.gov (United States)

    Lin, Chuan-Chuan; Lin, Hung-Yin; Chi, Ming-Hung; Shen, Chin-Min; Chen, Hwan-Wen; Yang, Wen-Jen; Lee, Mei-Hwa

    2014-07-01

    The choice of surfactants and cosurfactants for preparation of oral formulation in microemulsions is limited. In this report, a curcumin-encapsulated phospholipids-based microemulsion (ME) using food-grade ingredients soybean oil and soybean lecithin to replace ethyl oleate and purified lecithin from our previous study was established and compared. The results indicated soybean oil is superior to ethyl oleate as the oil phase in curcumin microemulsion, as proven by the broadened microemulsion region with increasing range of surfactant/soybean oil ratio (approx. 1:1-12:1). Further preparation of two formula with different particle sizes of formula A (30nm) and B (80nm) exhibited differential effects on the cytotoxicity of hepatocellular HepG2 cell lines. At 15μM of concentration, curcumin-ME in formula A with smaller particle size resulted in the lowest viability (approx. 5%), which might be explained by increasing intake of curcumin, as observed by fluorescence microscopy. In addition, the cytotoxic effect of curcumin-ME is exclusively prominent on HepG2, not on HEK293, which showed over 80% of viability at 15μM. The results from this study might provide an innovative applied technique in the area of nutraceuticals and functional foods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Production of Food Grade Yeasts

    Directory of Open Access Journals (Sweden)

    Argyro Bekatorou

    2006-01-01

    Full Text Available Yeasts have been known to humans for thousands of years as they have been used in traditional fermentation processes like wine, beer and bread making. Today, yeasts are also used as alternative sources of high nutritional value proteins, enzymes and vitamins, and have numerous applications in the health food industry as food additives, conditioners and flavouring agents, for the production of microbiology media and extracts, as well as livestock feeds. Modern scientific advances allow the isolation, construction and industrial production of new yeast strains to satisfy the specific demands of the food industry. Types of commercial food grade yeasts, industrial production processes and raw materials are highlighted. Aspects of yeast metabolism, with respect to carbohydrate utilization, nutritional aspects and recent research advances are also discussed.

  8. 21 CFR 864.4400 - Enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Enzyme preparations. 864.4400 Section 864.4400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Specimen Preparation Reagents § 864.4400 Enzyme...

  9. Process for preparing multilayer enzyme coating on a fiber

    Science.gov (United States)

    Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

    2009-11-03

    A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

  10. Preparation of immobilized enzyme membrane by radiation-cast-polymerization

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1989-01-01

    The preparation of immobilized enzyme membranes was studied by radiation cast-polymerization at low temperatures using cellulase enzyme, hydrophilic and hydrophobic monomers. The enzyme activity of the membranes was affected by monomer concentration, membrane thickness, and hydrophilicity of monomer, in which the membranes with 100 μm thickness from high monomer concentration (80%) had high enzyme activity, which was similar to that of the membranes with 1.0 mm thickness from low monomer concentration (20%). (author)

  11. Microbial Production of Food Grade Pigments

    Directory of Open Access Journals (Sweden)

    Laurent Dufossé

    2006-01-01

    Full Text Available The controversial topic of synthetic dyes in food has been discussed for many years. The scrutiny and negative assessment of synthetic food dyes by the modern consumer have raised a strong interest in natural colouring alternatives. Nature is rich in colours (minerals, plants, microalgae, etc., and pigment-producing microorganisms (fungi, yeasts, bacteria are quite common. Among the molecules produced by microorganisms are carotenoids, melanins, flavins, quinones, and more specifically monascins, violacein or indigo. The success of any pigment produced by fermentation depends upon its acceptability on the market, regulatory approval, and the size of the capital investment required to bring the product to market. A few years ago, some expressed doubts about the successful commercialization of fermentation-derived food grade pigments because of the high capital investment requirements for fermentation facilities and the extensive and lengthy toxicity studies required by regulatory agencies. Public perception of biotechnology-derived products also had to be taken into account. Nowadays some fermentative food grade pigments are on the market: Monascus pigments, astaxanthin from Xanthophyllomyces dendrorhous, Arpink Red from Penicillium oxalicum, riboflavin from Ashbya gossypii, b-carotene from Blakeslea trispora. The successful marketing of pigments derived from algae or extracted from plants, both as a food colour and a nutritional supplement, reflects the presence and importance of niche markets in which consumers are willing to pay a premium for »all natural ingredients«.

  12. Enzymes of industrial purpose - review of the market of enzyme preparations and prospects for its development

    Directory of Open Access Journals (Sweden)

    A. A. Tolkacheva

    2017-01-01

    Full Text Available Microbial enzyme preparations are increasingly replacing conventional chemical catalysts in a number of industrial processes. Such drugs, in addition to environmental friendliness and high activity, have a number of advantages over enzyme preparations of vegetable and animal origin, namely: the production of microbial enzymes in bioreactors is easily controlled and predictable; excreted microbiological enzymes are more stable than intracellular animals and plant enzymes; the genetic diversity of microorganisms makes it possible to produce enzyme preparations with a wide range of specificity; microbiological enzymes can be synthesized year-round, in contrast to the production of plant enzymes, which is often seasonal. The leaders of the world market of enzymes are proteases and amylases, which account for 25% and 15%, respectively. Over the past five years, the world market for carbohydrases, including mainly amylases, cellulases and xylanases, has been the fastest growing segment of the enzyme market with an aggregate annual growth rate of more than 7.0%. Another major product of the industrial enzyme market, which has a great potential for growth, is lipases. From the point of view of designation, the main part is represented by food and food enzymes. The Russian market continues to be unsaturated - the current supply is not able to meet the needs of the Russian feed and food industry in enzyme preparations. Enzyme preparations of domestic producers are in demand in forage production, while food industrial enterprises prefer imported products. The most significant enterprises in the enzymatic industry in Russia at the moment are Sibbiofarm, AgroSistema, Agroferment. In the light of the Russian policy of increasing food security, the development of the domestic enzyme industry is an extremely topical task.

  13. Continuous enzyme reactions with immobilized enzyme tubes prepared by radiation cast-polymerization

    International Nuclear Information System (INIS)

    Kumakura, Minoru; Kaetsu, Isao

    1986-01-01

    Immobilized glucose oxidase tubes were prepared by radiation cast-polymerization of 2-hydroxyethyl methacrylate and tetraethyleneglycol diacrylate monomer at low temperatures. The immobilized enzyme tubes which were spirally set in a water bath were used as reactor, in which the enzyme activity varied with tube size and flow rate of the substrate. The conversion yield of the substrate in continuous enzyme reaction was about 80%. (author)

  14. MICROEMULSION OF MIXED CHLORINATED SOLVENTS USING FOOD GRADE (EDIBLE) SURFACTANTS

    Science.gov (United States)

    Ground water contamination frequently consists of mixed chlorinated solvents [e.g., tetrachloroethylene (PCE), trichloroethylene (TCE), and trans-1,2- dichloroethylene (DCE)]. In this research, mixtures of the food grade (edible) surfactants bis(2-ethylhexyl) sodium sulfosuccinat...

  15. On WHO Guidelines "Fortification of food grade salt"

    Directory of Open Access Journals (Sweden)

    Grigoriy Anatol'evich Gerasimov

    2015-01-01

    Full Text Available Issues of implementation of WHO Guidelines on fortification of food grade salt with iodine for the prevention and control of iodine deficiency disorders in countries of Eastern Europe and Central Asia are discussed.

  16. Rheological characterization of modified foodstuffs with food grade thickening agents

    Science.gov (United States)

    Reyes-Ocampo, I.; Aguayo-Vallejo, JP; Ascanio, G.; Córdova-Aguilar, MS

    2017-01-01

    This work describes a rheological characterization in terms of shear and extensional properties of whole milk, modified with food grade thickening agents (xanthan and carboxymethyl cellulose) with the purpose of being utilized in dysphagia treatment. Shear viscosity of the thickened fluids (2% wt. of xanthan and CMC) were measured in a stress-controlled rheometer and for extensional viscosity, a custom-built orifice flowmeter was used, with elongation rates from 20 to 3000 s-1. Such elongation-rate values represent the entire swallowing process, including the pharyngeal and esophageal phases. The steady-state shear and extensional flow curves were compared with the flow curve of a pudding consistency BaSO4 suspension (α=05), typically used as a reference fluid for the specialized commercial dysphagia products. The modified fluids presented non-Newtonian behavior in both, shear and extensional flows, and the comparison with the reference fluid show that the thickened milk prepared here, can be safely used for consumption by patients with severe dysphagia.

  17. Preparation by irradiation of a solid support for enzyme immunoassay

    International Nuclear Information System (INIS)

    Kumakura, M.; Kaetsu, I.

    1984-01-01

    Reagents (immobilized anti-α-fetoprotein discs) having a porous structure were prepared for enzyme immunoassay of α-fetoprotein by radiation polymerization at low temperatures. Discs were attached to sticks for easy handling. The activity (determined by absorbance at 492 nm) of the discs varied with the hydrophilic properties and size of the discs. The discs are sufficiently sensitive and precise for enzyme immunoassay of α-fetoprotein. Anti-AFP dissolved in PBS solution was mixed with a monomer solution of hydroxyethyl methacrylate and hydroxypropyl methacrylate. The mixture was frozen to -78 0 C and gamma irradiated. (Auth.)

  18. 21 CFR 184.1420 - Lipase enzyme preparation derived from Rhizopus niveus.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lipase enzyme preparation derived from Rhizopus... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1420 Lipase enzyme preparation derived from Rhizopus niveus. (a) Lipase enzyme preparation contains lipase enzyme (CAS Reg. No...

  19. Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads

    NARCIS (Netherlands)

    Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2017-01-01

    We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a

  20. Electron beam technology for production of preparations of immobilized enzymes

    International Nuclear Information System (INIS)

    Gonchar, A.M.; Auslender, V.L.; Polyakov, V.A.

    1995-01-01

    Possibility of electron beam usage for proteases immobilization on 1,4-polyalkylene oxide (1,4-PAO) was studied to obtain biologically active complex for multi-purpose usage. It is shown that immobilization of Bacillus Subtilis protease is done due to free-radical linking of enzyme and carrier with formation of mycelium-like structures. Immobilization improves heat resistance of enzyme up to 60 centigrade without substrate and up to 80 centigrade in presence of substrate, widens range pH activity in comparison with non-immobilized forms. Immobilized proteases does not contain peroxides and long-live radicals. Our results permitted to create technologies for production of medical and veterinary preparations, active components for wool washing agents and leather fabrication technology

  1. 21 CFR 184.1012 - α-Amylase enzyme preparation from Bacillus stearothermophilus.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true α-Amylase enzyme preparation from Bacillus... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1012 α-Amylase enzyme preparation from Bacillus stearothermophilus. (a) α-Amylase enzyme preparation is obtained from the culture...

  2. 21 CFR 184.1388 - Lactase enzyme preparation from Kluyveromyces lactis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactase enzyme preparation from Kluyveromyces... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1388 Lactase enzyme preparation from Kluyveromyces lactis. (a) This enzyme preparation is derived from the nonpathogenic...

  3. An ultra melt-resistant hydrogel from food grade carbohydrates

    NARCIS (Netherlands)

    Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2017-01-01

    We report a binary hydrogel system made from two food grade biopolymers, agar and methylcellulose (agar-MC), which does not require addition of salt for gelation to occur and has very unusual rheological and thermal properties. It is found that the storage modulus of the agar-MC hydrogel far

  4. Flavourzyme, an Enzyme Preparation with Industrial Relevance: Automated Nine-Step Purification and Partial Characterization of Eight Enzymes.

    Science.gov (United States)

    Merz, Michael; Eisele, Thomas; Berends, Pieter; Appel, Daniel; Rabe, Swen; Blank, Imre; Stressler, Timo; Fischer, Lutz

    2015-06-17

    Flavourzyme is sold as a peptidase preparation from Aspergillus oryzae. The enzyme preparation is widely and diversely used for protein hydrolysis in industrial and research applications. However, detailed information about the composition of this mixture is still missing due to the complexity. The present study identified eight key enzymes by mass spectrometry and partially by activity staining on native polyacrylamide gels or gel zymography. The eight enzymes identified were two aminopeptidases, two dipeptidyl peptidases, three endopeptidases, and one α-amylase from the A. oryzae strain ATCC 42149/RIB 40 (yellow koji mold). Various specific marker substrates for these Flavourzyme enzymes were ascertained. An automated, time-saving nine-step protocol for the purification of all eight enzymes within 7 h was designed. Finally, the purified Flavourzyme enzymes were biochemically characterized with regard to pH and temperature profiles and molecular sizes.

  5. 21 CFR 184.1387 - Lactase enzyme preparation from Candida pseudotropicalis.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactase enzyme preparation from Candida pseudotropicalis. 184.1387 Section 184.1387 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... preparation from Candida pseudotropicalis. (a) This enzyme preparation is derived from the nonpathogenic...

  6. Impact of food grade and nano-TiO2 particles on a human intestinal community.

    Science.gov (United States)

    Dudefoi, William; Moniz, Kristy; Allen-Vercoe, Emma; Ropers, Marie-Hélène; Walker, Virginia K

    2017-08-01

    Titanium dioxide (TiO 2 ) nanoparticles (NPs) are used as an additive (E171 or INS171) in foods such as gum, candy and puddings. To address concerns about the potential hazardous effects of ingested NPs, the toxicity of these food-grade NPs was investigated with a defined model intestinal bacterial community. Each titania preparation (food-grade TiO 2 formulations, E171-1 and E171-6a) was tested at concentrations equivalent to those found in the human intestine after sampling 1-2 pieces of gum or candy (100-250 ppm). At the low concentrations used, neither the TiO 2 food additives nor control TiO 2 NPs had an impact on gas production and only a minor effect on fatty acids profiles (C16:00, C18:00, 15:1 w5c, 18:1 w9c and 18:1 w9c, p < 0.05). DNA profiles and phylogenetic distributions confirmed limited effects on the bacterial community, with a modest decrease in the relative abundance of the dominant Bacteroides ovatus in favor of Clostridium cocleatum (-13% and +14% respectively, p < 0.05). Such minor shifts in the treated consortia suggest that food grade and nano-TiO 2 particles do not have a major effect on human gut microbiota when tested in vitro at relevant low concentrations. However, the cumulative effects of chronic TiO 2 NP ingestion remain to be tested. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Application of residual polysaccharide-degrading enzymes in dried shiitake mushrooms as an enzyme preparation in food processing.

    Science.gov (United States)

    Tatsumi, E; Konishi, Y; Tsujiyama, S

    2016-11-01

    To examine the activities of residual enzymes in dried shiitake mushrooms, which are a traditional foodstuff in Japanese cuisine, for possible applications in food processing. Polysaccharide-degrading enzymes remained intact in dried shiitake mushrooms and the activities of amylase, β-glucosidase and pectinase were high. A potato digestion was tested using dried shiitake powder. The enzymes reacted with potato tuber specimens to solubilize sugars even under a heterogeneous solid-state condition and that their reaction modes were different at 38 and 50 °C. Dried shiitake mushrooms have a potential use in food processing as an enzyme preparation.

  8. Construction of a novel, stable, food-grade expression system by engineering the endogenous toxin-antitoxin system in Bacillus subtilis.

    Science.gov (United States)

    Yang, Sen; Kang, Zhen; Cao, Wenlong; Du, Guocheng; Chen, Jian

    2016-02-10

    Bacillus subtilis as an important workhorse that has been widely used to produce enzymes and metabolites. To broaden its applications, especially in the food and feed industry, we constructed a novel, stable, food-grade expression system by engineering its type II toxin-antitoxin system. The expression of the toxin EndoA, encoded by the chromosomal ydcE gene, was regulated by an endogenous, xylose-inducible promoter, while the ydcD gene, which encodes the unstable antitoxin EndoB, was inserted into a food-grade vector backbone, where its expression was driven by the native, constitutive promoter PylxM. By maintaining the xylose concentration above 2.0 g L(-1), this auto-regulated expression system was absolutely stable after 100 generations. Compared with traditional antibiotic-dependent expression systems, this novel expression system resulted in greater biomass and higher titers of desired products (enzymes or metabolites). Our results demonstrate that this stable, food-grade expression system is suitable for enzyme production and pathway engineering, especially for the production of food-grade enzymes and metabolites. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Food-Grade Synthesis of Maillard-Type Taste Enhancers Using Natural Deep Eutectic Solvents (NADES).

    Science.gov (United States)

    Kranz, Maximilian; Hofmann, Thomas

    2018-01-28

    The increasing demand for healthier food products, with reduced levels of table salt, sugar, and mono sodium glutamate, reinforce the need for novel taste enhancers prepared by means of food-grade kitchen-type chemistry. Although several taste modulating compounds have been discovered in processed foods, their Maillard-type ex food production is usually not exploited by industrial process reactions as the yields of target compounds typically do not exceed 1-2%. Natural deep eutectic solvents (NADES) are reported for the first time to significantly increase the yields of the taste enhancers 1-deoxy-ᴅ-fructosyl-N-β-alanyl-ʟ-histidine (49% yield), N-(1-methyl-4-oxoimidazolidin-2-ylidene) aminopropionic acid (54% yield) and N²-(1-carboxyethyl) guanosine 5'-monophosphate (22% yield) at low temperature (80-100 °C) within a maximum reaction time of 2 h. Therefore, NADES open new avenues to a "next-generation culinary chemistry" overcoming the yield limitations of traditional Maillard chemistry approaches and enable a food-grade Maillard-type generation of flavor modulators.

  10. Food-Grade Synthesis of Maillard-Type Taste Enhancers Using Natural Deep Eutectic Solvents (NADES

    Directory of Open Access Journals (Sweden)

    Maximilian Kranz

    2018-01-01

    Full Text Available The increasing demand for healthier food products, with reduced levels of table salt, sugar, and mono sodium glutamate, reinforce the need for novel taste enhancers prepared by means of food-grade kitchen-type chemistry. Although several taste modulating compounds have been discovered in processed foods, their Maillard-type ex food production is usually not exploited by industrial process reactions as the yields of target compounds typically do not exceed 1–2%. Natural deep eutectic solvents (NADES are reported for the first time to significantly increase the yields of the taste enhancers 1-deoxy-ᴅ-fructosyl-N-β-alanyl-ʟ-histidine (49% yield, N-(1-methyl-4-oxoimidazolidin-2-ylidene aminopropionic acid (54% yield and N2-(1-carboxyethyl guanosine 5′-monophosphate (22% yield at low temperature (80–100 °C within a maximum reaction time of 2 h. Therefore, NADES open new avenues to a “next-generation culinary chemistry” overcoming the yield limitations of traditional Maillard chemistry approaches and enable a food-grade Maillard-type generation of flavor modulators.

  11. 21 CFR 184.1924 - Urease enzyme preparation from Lactobacillus fermentum.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urease enzyme preparation from Lactobacillus... GENERALLY RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1924 Urease enzyme..., nontoxicogenic bacterium Lactobacillus fermentum. It contains the enzyme urease (CAS Reg. No. 9002-13-5), which...

  12. Method and apparatus for producing food grade carbon dioxide

    International Nuclear Information System (INIS)

    Nobles, J.E.; Swenson, L.K.

    1984-01-01

    A method is disclosed of producing food grade carbon dioxide from an impure carbon dioxide source stream containing contaminants which may include light and heavy hydrocarbons (at least C 1 to C 3 ) and light sulfur compounds such as hydrogen sulfide and carbonyl sulfide as well as heavier sulfur constituents in the nature of mercaptans (RSH) and/or organic mono and disulfides (RSR and RSSR). Nitrogen, water and/or oxygen may also be present in varying amounts in the impure feed stream. The feed gas is first rectified with liquid carbon dioxide condensed from a part of the feed stream to remove heavy hydrocarbons and heavy sulfur compounds, then passed through an absorber to effect removal of the light sulfur compounds, next subjected to an oxidizing atmosphere capable of converting all of the C 2 hydrocarbons and optionally a part of the methane to carbon oxides and water, chilled to condense the water in the remaining gas stream without formation of hydrates, liquefied for ease of handling and storage and finally stripped to remove residual contaminants such as methane, carbon monoxide and nitrogen to produce the final food grade carbon dioxide product

  13. 21 CFR 184.1250 - Cellulase enzyme preparation derived from Trichoderma longibrachiatum.

    Science.gov (United States)

    2010-04-01

    ... Trichoderma longibrachiatum. 184.1250 Section 184.1250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT....1250 Cellulase enzyme preparation derived from Trichoderma longibrachiatum. (a) Cellulase enzyme preparation is derived from a nonpathogenic, nontoxicogenic strain of Trichoderma longibrachiatum (formerly T...

  14. 21 CFR 173.357 - Materials used as fixing agents in the immobilization of enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... glucose isomerase enzyme preparations for use in the manufacture of high fructose corn syrup, in... manufacture of high fructose corn syrup, in accordance with § 184.1372 of this chapter. Cellulose triacetate... enzyme preparations for use in the manufacture of high fructose corn syrup, in accordance with § 184.1372...

  15. Preparation of antioxidant enzymatic hydrolysates from honeybee-collected pollen using plant enzymes.

    Science.gov (United States)

    Marinova, Margarita D; Tchorbanov, Bozhidar P

    2011-01-09

    Enzymatic hydrolysates of honeybee-collected pollen were prepared using food-grade proteinase and aminopeptidases entirely of plant origin. Bromelain from pineapple stem was applied (8 mAU/g substrate) in the first hydrolysis stage. Aminopeptidase (0.05 U/g substrate) and proline iminopeptidase (0.03 U/g substrate) from cabbage leaves (Brassica oleracea var. capitata), and aminopeptidase (0.2 U/g substrate) from chick-pea cotyledons (Cicer arietinum L.) were involved in the additional hydrolysis of the peptide mixtures. The degree of hydrolysis (DH), total phenolic contents, and protein contents of these hydrolysates were as follows: DH (about 20-28%), total phenolics (15.3-27.2 μg/mg sample powder), and proteins (162.7-242.8 μg/mg sample powder), respectively. The hydrolysates possessed high antiradical scavenging activity determined with DPPH (42-46% inhibition). The prepared hydrolysates of bee-collected flower pollen may be regarded as effective natural and functional dietary food supplements due to their remarkable content of polyphenol substances and significant radical-scavenging capacity with special regard to their nutritional-physiological implications.

  16. Preparation of Antioxidant Enzymatic Hydrolysates from Honeybee-Collected Pollen Using Plant Enzymes

    Directory of Open Access Journals (Sweden)

    Margarita D. Marinova

    2010-01-01

    Full Text Available Enzymatic hydrolysates of honeybee-collected pollen were prepared using food-grade proteinase and aminopeptidases entirely of plant origin. Bromelain from pineapple stem was applied (8 mAU/g substrate in the first hydrolysis stage. Aminopeptidase (0.05 U/g substrate and proline iminopeptidase (0.03 U/g substrate from cabbage leaves (Brassica oleracea var. capitata, and aminopeptidase (0.2 U/g substrate from chick-pea cotyledons (Cicer arietinum L. were involved in the additional hydrolysis of the peptide mixtures. The degree of hydrolysis (DH, total phenolic contents, and protein contents of these hydrolysates were as follows: DH (about 20–28%, total phenolics (15.3–27.2 μg/mg sample powder, and proteins (162.7–242.8 μg/mg sample powder, respectively. The hydrolysates possessed high antiradical scavenging activity determined with DPPH (42–46% inhibition. The prepared hydrolysates of bee-collected flower pollen may be regarded as effective natural and functional dietary food supplements due to their remarkable content of polyphenol substances and significant radical-scavenging capacity with special regard to their nutritional-physiological implications.

  17. 21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... high fructose corn syrup described in § 184.1866. They are derived from recognized species of precisely... ingredient is used as an enzyme, as defined in § 170.3(o)(9) of this chapter, to convert glucose to fructose. (2) The ingredient is used in high fructose corn syrup, at levels not to exceed current good...

  18. 21 CFR 184.1150 - Bacterially-derived protease enzyme preparation.

    Science.gov (United States)

    2010-04-01

    ... filtrate resulting from a pure culture fermentation of a nonpathogenic and nontoxigenic strain of Bacillus subtilis or B. amyloliquefaciens. The preparation is characterized by the presence of the enzymes..._federal_regulations/ibr_locations.html. In addition, antibiotic activity is absent in the enzyme...

  19. Nuclear magnetic resonance characterization of apple juice containing enzyme preparations

    International Nuclear Information System (INIS)

    Prestes, Rosilene A.; Almeida, Denise Milleo; Barison, Andersson; Pinheiro, Luis Antonio; Wosiacki, Gilvan

    2012-01-01

    In this work, 1 H nuclear magnetic resonance ( 1 H NMR) was employed to evaluate changes in apple juice in response to the addition of Panzym Yieldmash and Ultrazym AFP-L enzymatic complexes and compare it with premium apple juice. The juice was processed at different temperatures and concentrations of enzymatic complexes. The differences in the results were attributed mainly to the enzyme concentrations, since temperature did not cause any variation. A quantitative analysis indicated that the concentration of fructose increased while the concentrations of sucrose and glucose decreased in response to increasing concentrations of the enzymatic complexes. (author)

  20. Development, Characterization, and Utilization of Food-Grade Polymer Oleogels.

    Science.gov (United States)

    Davidovich-Pinhas, M; Barbut, Shai; Marangoni, A G

    2016-01-01

    The potential of organogels (oleogels) for oil structuring has been identified and investigated extensively using different gelator-oil systems in recent years. This review provides a comprehensive summary of all oil-structuring systems found in the literature, with an emphasis on ethyl-cellulose (EC), the only direct food-grade polymer oleogelator. EC is a semicrystalline material that undergoes a thermoreversible sol-gel transition in the presence of liquid oil. This unique behavior is based on the polymer's ability to associate through physical bonds. These interactions are strongly affected by external fields such as shear and temperature, as well as by solvent chemistry, which in turn strongly affect final gel properties. Recently, EC-based oleogels have been used as a replacement for fats in foods, as heat-resistance agents in chocolate, as oil-binding agents in bakery products, and as the basis for cosmetic pastes. Understanding the characteristics of the EC oleogel is essential for the development of new applications.

  1. Food-grade host/vector expression system for Lactobacillus casei based on complementation of plasmid-associated phospho-beta-galactosidase gene lacG.

    Science.gov (United States)

    Takala, T M; Saris, P E J; Tynkkynen, S S H

    2003-01-01

    A new food-grade host/vector system for Lactobacillus casei based on lactose selection was constructed. The wild-type non-starter host Lb. casei strain E utilizes lactose via a plasmid-encoded phosphotransferase system. For food-grade cloning, a stable lactose-deficient mutant was constructed by deleting a 141-bp fragment from the phospho-beta-galactosidase gene lacG via gene replacement. The deletion resulted in an inactive phospho-beta-galactosidase enzyme with an internal in-frame deletion of 47 amino acids. A complementation plasmid was constructed containing a replicon from Lactococcus lactis, the lacG gene from Lb. casei, and the constitutive promoter of pepR for lacG expression from Lb. rhamnosus. The expression of the lacG gene from the resulting food-grade plasmid pLEB600 restored the ability of the lactose-negative mutant strain to grow on lactose to the wild-type level. The vector pLEB600 was used for expression of the proline iminopeptidase gene pepI from Lb. helveticus in Lb. casei. The results show that the food-grade expression system reported in this paper can be used for expression of foreign genes in Lb. casei.

  2. Evaluation of a Hypocrea jecorina Enzyme Preparation for Hydrolysis of Tifton 85 Bermudagrass

    Science.gov (United States)

    Ximenes, E. A.; Brandon, S. K.; Doran-Peterson, J.

    Tifton 85 bermudagrass, developed at the ARS-USDA in Tifton, GA, is grown on over ten million acres in the USA for hay and forage. Of the bermudagrass cultivars, Tifton 85 exhibits improved digestibility because the ratio of ether- to ester-linked phenolic acids has been lowered using traditional plant breeding techniques. A previously developed pressurized batch hot water (PBHW) method was used to treat Tifton 85 bermudagrass for enzymatic hydrolysis. Native grass (untreated) and PBHW-pretreated material were compared as substrates for fungal cultivation to produce enzymes. Cellulase activity, measured via the filter paper assay, was higher for fungi cultivated on PBHW-pretreated grass, whereas the other nine enzyme assays produced higher activities for the untreated grass. Ferulic acid and vanillin levels increased significantly for the enzyme preparations produced using PBHW-pretreated grass and the release of these phenolic compounds may have contributed to the observed reduction in enzyme activities. Culture supernatant from Tifton 85 bermudagrass-grown fungi were combined with two commercial enzyme preparations and the enzyme activity profiles are reported. The amount of reducing sugar liberated by the enzyme mixture from Hypocrea jecorina (after 192 h incubation with untreated bermudagrass) individually or in combination with feruloyl esterase was 72.1 and 84.8%, respectively, of the commercial cellulase preparation analyzed under the same conditions.

  3. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

    International Nuclear Information System (INIS)

    Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

    2016-01-01

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N_α-benzoyl-L-arginine ethyl ester to N_α-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

  4. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Guihua, E-mail: guihuaruan@hotmail.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China); Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Du, Fuyou, E-mail: dufu2005@126.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China)

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

  5. BAURAN PEMASARAN PRODUK BARU PELUMAS FOOD GRADE GREASE BERBAHAN DaSAR MINYAK SAWIT

    Directory of Open Access Journals (Sweden)

    Ali Maksum

    2016-12-01

    Full Text Available Grease with food grade specification is essentially required on food processing production activities.  The purpose of this study is to develop a new product marketing mix for food grade grease, i.e 1 product priority, 2 pricing priority, 3 distribution priority and 4 advertising priority. This Research was conducted in Sub District Purbalingga and Padamara, Purbalingga regency with respondent SMEs food processing. Analysis of the determination of marketing mix that includes product, price, advertising and distribution using the Analytical Hierarchy Process (AHP. Sampling was purposive random sampling method with a population of 64 SMEs so drawn sample of 20 respondents. Result of the study showed the marketing mix priority which were: (1 advertising priority for the new food grade grease product with an ads that could attract the attention of consumers in order to made the consumers interested, tried, and bought the new food grade lubricating grease products. (2 Price priority for the new food grade grease products which was by determining the moderate prices to compete the competitors' prices while still maintained a high quality. (3 Product priority for new food grade grease product which was producing a qualified product which could withstand the wear of the engine, green colour of the product, a 350 g size packs with a rectangular shape packaging labels. (4 Distribution priority for the new food grade grease product which was a short distribution channels through mobile vendors so that the consumers were able to save costs, and got the product fast and easily

  6. Enzyme

    Science.gov (United States)

    Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For ... use them. Blood clotting is another example of enzymes at work. Enzymes are needed for all body ...

  7. Enzyme production in immobilized Trichoderma reesei cells with hydrophobic polymers prepared by radiation polymerization method

    International Nuclear Information System (INIS)

    Luzhao Xin; Kumakura, Minoru; Kaetsu, Isao

    1993-01-01

    Trichoderma reesei cells were immobilized on paper covered with hydrophobic monomer, trimethylpropane triacrylate by radiation polymerization. The effect of immobilization condition on enzyme productivity was studied by measuring filter paper and cellobiose activity. The cells were adhered and grew on the surface of the carrier with the polymer giving high enzyme productivity in the immobilized cells in comparison with the free cells. Optimum concentration and volume of the coating monomer for the preparation of the immobilized cells were obtained. (author)

  8. Efficient production of D-tagatose using a food-grade surface display system.

    Science.gov (United States)

    Liu, Yi; Li, Sha; Xu, Hong; Wu, Lingtian; Xu, Zheng; Liu, Jing; Feng, Xiaohai

    2014-07-16

    D-tagatose, a functional sweetener, is commonly transformed from D-galactose by L-arabinose isomerase (L-AI). In this study, a novel type of biocatalyst, L-AI from Lactobacillus fermentum CGMCC2921 displayed on the spore surface of Bacillus subtilis 168, was developed for producing D-tagatose. The anchored L-AI, exhibiting the relatively high bioactivity, suggested that the surface display system using CotX as the anchoring protein was successfully constructed. The stability of the anchored L-AI was significantly improved. Specifically, the consolidation of thermal stability representing 87% of relative activity was retained even at 80 °C for 30 min, which remarkably favored the production of D-tagatose. Under the optimal conditions, the robust spores can convert 75% D-galactose (100 g/L) into D-tagatose after 24 h, and the conversion rate remained at 56% at the third cycle. Therefore, this biocatalysis system, which could express the target enzyme on the food-grade vector, was an alternative method for the value-added production of D-tagatose.

  9. Food grade lingonberry extract: polyphenolic composition and in vivo protective effect against oxidative stress.

    Science.gov (United States)

    Mane, Carine; Loonis, Michele; Juhel, Christine; Dufour, Claire; Malien-Aubert, Celine

    2011-04-13

    Fractionation of the polyphenols constituting a food grade lingonberry extract (Vaccinium vitis-idaea) highlighted a composition more complex than described until now in the berry. Procyanidins B1, B2, and A2 were identified by UPLC/ESI-MS(2) along with the presence of other flavanol oligomers. Processing induced the release of large amounts of aglycones for ferulic acid, p-coumaric acid, and quercetin. The described anthocyanic composition of lingonberry was completed with hexoside derivatives of peonidin, petunidin, malvidin, and delphinidin. Besides confirmation of in vitro antioxidant activity, in vivo study was performed on rats fed a diet inducing oxidative stress. Supplementation with lingonberry extract significantly decreased the total oxidant status and favorably affected antioxidant defense enzymes in red blood cells and liver. A drop in the serum reduced glutathione level was also prevented, and uric acid was maintained at low level, confirming the antioxidant activity of the extract (5% proanthocyanidins) from a dosage of 23 mg/kg of body weight.

  10. Bitterness in sodium caseinate hydrolysates: role of enzyme preparation and degree of hydrolysis.

    Science.gov (United States)

    O'Sullivan, Dara; Nongonierma, Alice B; FitzGerald, Richard J

    2017-10-01

    Enzymatic hydrolysis of sodium caseinate (NaCas) may lead to the development of bitterness. Careful selection of hydrolysis conditions (i.e. enzyme preparation and duration) yielding different degrees of hydrolysis (DH) may aid in the development of low bitterness. Eighteen NaCas hydrolysates were generated with four enzyme preparations (Alcalase 2.4L, Prolyve 1000, FlavorPro Whey and pepsin) to different DH values. Hydrolysate bitterness score, assessed using a trained panel (ten assessors), generally increased at higher DH values for Alcalase, Prolyve and pepsin hydrolysates. However, all FlavorPro Whey hydrolysates (DH 0.38-10.62%) displayed low bitterness score values ( 0.05). Enzyme preparation and DH affect the bitterness of NaCas hydrolysates. The results are relevant for the generation of NaCas hydrolysates with reduced bitterness. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  11. Inhibition of raw starch digestion by one glucoamylase preparation from black Aspergillus at high enzyme concentration

    Energy Technology Data Exchange (ETDEWEB)

    Saka, B C; Veda, S

    1981-09-01

    Raw starch digestion by glucoamylase I (Ab. G-I) preparation from black Aspergillus was inhibited significantly at relatively high concentration of the enzyme. The properties of this enzyme were studied together with those of another glucoamylase I (Nor. G-I), also from black Aspergillus. The two glucoamylases do not differ so much in their physico-chemical properties such as molecular weight, pH and thermal stability, pH and temperature optimum, substrate specificity, debranching activity, isoelectric point etc. The adsorption rate of both enzymes on raw starch increased by the increase of enzyme concentration. The raw starch digestion rate by adsorbed Ab. G-I, however, was decreased with the increase of concentration of enzyme whereas the same was increased in case of Nor. G-I. The inhibitory effect was weaker at 60 deg. Celcius or above. (Refs. 11).

  12. Effects of commercial pectolytic and cellulolytic enzyme preparations on the apple cell wall.

    Science.gov (United States)

    Dongowski, G; Sembries, S

    2001-09-01

    The action of three different commercial enzyme combinations on apple cell wall material has been examined in a model system under conditions of mash and pomace treatment by using an alcohol-insoluble substance prepared from apples. A part of the total dietary fiber, for example, galacturonan (pectin), appeared in the soluble fraction after enzymatic mash treatment. The soluble fraction increased intensely during pomace treatment. Furthermore, enzyme actions caused a change in the water-binding capacity of residues as well as changes in the monosaccharide composition and in the molecular weight distribution of saccharides in filtrates (soluble parts). The extent of decomposition of cell wall material and the increase of soluble oligomeric and/or polymeric dietary fiber components are caused by both the composition (pectinases, cellulases, and hemicellulases) and the activities of the enzyme preparations. The model experiments allow an insight into the reactions occurring during enzyme action on the plant cell wall, for example, during apple juice production using pectolytic and cellulolytic enzyme preparations.

  13. 21 CFR 184.1148 - Bacterially-derived carbohydrase enzyme preparation.

    Science.gov (United States)

    2010-04-01

    ... Bacillus subtilis or B. amyloliquefaciens. The preparation is characterized by the presence of the enzymes.../code_of_federal_regulations/ibr_locations.html. In addition, antibiotic activity is absent in the... of antibiotic activity” in the Compendium of Food Additive Specifications, vol. 2, Joint FAO/WHO...

  14. Preparation of supramolecular hydrogel-enzyme hybrids exhibiting biomolecule-responsive gel degradation.

    Science.gov (United States)

    Shigemitsu, Hajime; Fujisaku, Takahiro; Onogi, Shoji; Yoshii, Tatsuyuki; Ikeda, Masato; Hamachi, Itaru

    2016-09-01

    Hydrogelators are small, self-assembling molecules that form supramolecular nanofiber networks that exhibit unique dynamic properties. Development of supramolecular hydrogels that degrade in response to various biomolecules could potentially be used for applications in areas such as drug delivery and diagnostics. Here we provide a synthetic procedure for preparing redox-responsive supramolecular hydrogelators that are used to create hydrogels that degrade in response to oxidizing or reducing conditions. The synthesis takes ∼2-4 d, and it can potentially be carried out in parallel to prepare multiple hydrogelator candidates. This described solid-phase peptide synthesis protocol can be used to produce previously described hydrogelators or to construct a focused molecular library to efficiently discover and optimize new hydrogelators. In addition, we describe the preparation of redox-responsive supramolecular hydrogel-enzyme hybrids that are created by mixing aqueous solutions of hydrogelators and enzymes, which requires 2 h for completion. The resultant supramolecular hydrogel-enzyme hybrids exhibit gel degradation in response to various biomolecules, and can be rationally designed by connecting the chemical reactions of the hydrogelators with enzymatic reactions. Gel degradation in response to biomolecules as triggers occurs within a few hours. We also describe the preparation of hydrogel-enzyme hybrids arrayed on flat glass slides, enabling high-throughput analysis of biomolecules such as glucose, uric acid, lactate and so on by gel degradation, which is detectable by the naked eye. The protocol requires ∼6 h to prepare the hydrogel-enzyme hybrid array and to complete the biomolecule assay.

  15. Biodegradation of paraffin wax by crude Aspergillus enzyme preparations for potential use in removing paraffin deposits.

    Science.gov (United States)

    Zhang, Junhui; Xue, Quanhong; Gao, Hui; Wang, Ping

    2015-11-01

    Paraffin deposition problems have plagued the oil industry. Whist mechanical and chemical methods are problematic, microbiological method of paraffin removal is considered an alternative. However, studies have mainly investigated the use of bacteria, with little attention to the potential of fungi. The performance of six Aspergillus isolates to degrade paraffin wax was evaluated under laboratory conditions using solid enzyme preparations. The results showed that all the six enzyme preparations efficiently improved the solubility of paraffin wax in n-hexane and degraded n-alkanes in paraffin wax. The degradation process was accompanied by dynamic production of gases (CO2 and H2 ) and organic acids (oxalate and propionate). The shape of wax crystals markedly changed after enzymatic degradation, with a rough surface and a loose structure. This study indicates that extracellular enzymes from Aspergillus spp. can efficiently degrade paraffin wax. These enzyme preparations have the potential for use in oil wells with paraffin deposition problems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Enzyme-Free Electrochemical Glucose Sensors Prepared by Dealloying Pd-Ni-P Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Yuqiao Zeng

    2014-01-01

    Full Text Available We report the formation of enzyme-free electrochemical glucose sensors by electrochemical dealloying palladium-containing Pd-Ni-P metallic glasses. When metallic glasses with different Pd contents are used as the dealloying precursor alloys, palladium-based nanoporous metals with different ligament and pore sizes can be obtained. The chemical compositions of the nanoporous metals also vary according to the different precursor compositions. All the as-obtained nanoporous metals exhibit electrochemical catalytic activity towards the oxidation of d-glucose, indicating that the nanoporous metals prepared by dealloying the Pd-Ni-P metallic glasses are promising materials for enzyme-free electrochemical glucose sensor.

  17. CONCERNING THE HYGIENIC STUDY OF ENZYME PREPARATIONS PRODUCED BY MICROFUNGI AND THEIR POSSIBLE USE IN THE FOOD INDUSTRY

    Science.gov (United States)

    Conclusions: (1) Large doses of enzyme preparations of the fungi Trichothecium roseum, Aspergillus oryzae strain No. 476I, and Aspergillus awamori...extensive industrial testing in the brewing industry, as well as enzyme preparations of the fungi Aspergillus oryzae strain No. 476I and Aspergillus

  18. Redistribution of mineral elements in wheat grain when applying the complex enzyme preparations based on phytase

    Directory of Open Access Journals (Sweden)

    Elena Kuznetsova

    2016-01-01

    Full Text Available Biogenic minerals play an important role in the whole human nutrition, but they are included in the grain of the phytates that reduces their bioavailability. Whole wheat bread is generally considered a healthy food, but the presence of mineral elements in it is insignificant, because of weak phytate degradation. From all sources of exogenous phytase the most productive are microscopic fungi. To accelerate the process of transition hard mineral elements are mobilized to implement integrated cellulolytic enzyme preparation based on the actions of phytase (producer is Penicillium canescens. Phytase activity was assessed indirectly by the rate of release of phosphate from the substrate. It has been established that the release rate of the phosphoric acid substrate is dependent on the composition of the drug and the enzyme complex is determined by the presence of xylanase. The presented experimental data shows that a cellulase treatment of the grain in conjunction with the β-glucanase or xylanase leading to an increase in phytase activity could be 1.4 - 2.3 times as compared with the individual enzymes. As a result of concerted action of enzymes complex preparation varies topography grain, increase the pore sizes in seed and fruit shells that facilitate the penetration of the enzyme phytase in the aleurone layer to the site of phytin hydrolysis and leads to an increase in phytase activity. In terms of rational parameters of enzymatic hydrolysis, the distribution of mineral elements in the anatomical parts of the grain after processing complex enzyme preparation with the help of X-ray detector EMF miniCup system in a scanning electron microscope JEOL JSM 6390 were investigated. When processing enzyme preparation wheat trend in the distribution of mineral elements, characteristic of grain - the proportion of these elements in the aleurone layer decreases, and in the endosperm increases. Because dietary fiber and phytate found together in the

  19. Do new cellulolytic enzyme preparations affect the industrial strategies for high solids lignocellulosic ethanol production?

    DEFF Research Database (Denmark)

    Cannella, David; Jørgensen, Henning

    2014-01-01

    proven essential for economic feasibility at industrial scale. Historically, simultaneous saccharification and fermentation (SSF) was found to give better ethanol yields compared to separate hydrolysis and fermentation (SHF), but data in literature are typically based on operating the process at low dry...... matter conditions. In this work the impact of selected enzyme preparation and processing strategy (SHF, presaccharification and simultaneous saccharification and fermentation—PSSF, and SSF) on final ethanol yield and overall performance was investigated with pretreated wheat straw up to 30% DM...... cellulose to around 94%, revealing that the most relevant products could be accounted for. One observation was the presence of oxidized sugar (gluconic acid) upon enzymatic hydrolysis with the latest enzyme preparation. Experiments showed gluconic acid formation by recently discovered enzymatic class...

  20. Catalase activity of a crude enzyme preparation from iron-chlorotic barley (Hordeum vulgaris) seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Kotaka, S; Krueger, A P; Andriese, P C

    1964-12-19

    An attempt is made to investigate the effect of Fe-EDTA on catalase activity of the enzyme preparation from iron-chlorotic barley. It has been observed that the addition of iron in the form of iron-potassium-ethylene-tetraacetate to cell-free extracts prepared from barley seedlings which had developed chlorosis produced a marked increase in the catalase activity of the extracts. Results are presented which indicate that the pattern of increase in catalase activity is related to the extent of chlorosis. 7 references, 3 figures.

  1. Stable preparations of tyrosine hydroxylase provide the solution structure of the full-length enzyme

    Science.gov (United States)

    Bezem, Maria T.; Baumann, Anne; Skjærven, Lars; Meyer, Romain; Kursula, Petri; Martinez, Aurora; Flydal, Marte I.

    2016-01-01

    Tyrosine hydroxylase (TH) catalyzes the rate-limiting step in the biosynthesis of catecholamine neurotransmitters. TH is a highly complex enzyme at mechanistic, structural, and regulatory levels, and the preparation of kinetically and conformationally stable enzyme for structural characterization has been challenging. Here, we report on improved protocols for purification of recombinant human TH isoform 1 (TH1), which provide large amounts of pure, stable, active TH1 with an intact N-terminus. TH1 purified through fusion with a His-tagged maltose-binding protein on amylose resin was representative of the iron-bound functional enzyme, showing high activity and stabilization by the natural feedback inhibitor dopamine. TH1 purified through fusion with a His-tagged ZZ domain on TALON is remarkably stable, as it was partially inhibited by resin-derived cobalt. This more stable enzyme preparation provided high-quality small-angle X-ray scattering (SAXS) data and reliable structural models of full-length tetrameric TH1. The SAXS-derived model reveals an elongated conformation (Dmax = 20 nm) for TH1, different arrangement of the catalytic domains compared with the crystal structure of truncated forms, and an N-terminal region with an unstructured tail that hosts the phosphorylation sites and a separated Ala-rich helical motif that may have a role in regulation of TH by interacting with binding partners. PMID:27462005

  2. Expression of monellin in a food-grade delivery system in Saccharomyces cerevisiae.

    Science.gov (United States)

    Liu, Jun; Yan, Da-zhong; Zhao, Sheng-jun

    2015-10-01

    Genetically modified (GM) foods have caused much controversy. Construction of a food-grade delivery system is a desirable technique with presumptive impact on industrial applications from the perspective of bio-safety. The aim of this study was to construct a food-grade delivery system for Saccharomyces cerevisiae and to study the expression of monellin from the berries of the West African forest plant Dioscoreophyllum cumminsii in this system. A food-grade system for S. cerevisiae was constructed based on ribosomal DNA (rDNA)-mediated homologous recombination to enable high-copy-number integration of the expression cassette inserted into the rDNA locus. A copper resistance gene (CUP1) was used as the selection marker for yeast transformation. Because variants of transformants containing different copy numbers at the CUP1 locus can be readily selected after growth in the presence of elevated copper levels, we suggest that this system would prove useful in the generation of tandemly iterated gene clusters. Using this food-grade system, a single-chain monellin gene was heterologously expressed. The yield of monellin reached a maximum of 675 mg L(-1) . This system harbors exclusively S. cerevisiae DNA with no antibiotic resistance genes, and it should therefore be appropriate for safe use in the food industry. Monellin was shown to be expressed in this food-grade delivery system. To our knowledge, this is the first report so far on expression of monellin in a food-grade expression system in S. cerevisiae. © 2014 Society of Chemical Industry.

  3. Encapsulation of resveratrol in spherical particles of food grade hydrogels

    Directory of Open Access Journals (Sweden)

    Balanč Bojana D.

    2017-01-01

    Full Text Available The paper reports about the preparation and characterization of hydrogel particles containing liposomes loaded with resveratrol as an active compound. The materials used for preparation of the particles were chosen to be suitable for food industry. Different polymer concentrations affect particles shape, size, size distribution, as well as the release kinetics of resveratrol. The diameter of particles varied from 360 to 754 μm, while the narrow size distribution was observed for all types of particles. Release studies were performed in Franz diffusion cell and the results showed the prolonged release of resveratrol from all samples, but the sample with the highest content of polymer (2.5% w/w in particular stood out. The research provides useful information about liposomes containing active compound encapsulated in hydrogel matrices and offers the basis for its application in the food industry.

  4. Enzymes in Commercial Cellulase Preparations Bind Differently to Dioxane Extracted Lignins

    Energy Technology Data Exchange (ETDEWEB)

    Yarbrough, John M.; Mittal, Ashutosh; Katahira, Rui; Mansfield, Elisabeth; Taylor, Larry E.; Decker, Stephen R.; Himmel, Michael E.; Vinzant, Todd

    2017-04-24

    Commercial fungal cellulases used in biomass-to-biofuels processes can be grouped into three general classes: native, augmented, and engineered. To evaluate lignin binding affinities of different enzyme activities in various commercial cellulase formulations in order to determine if enzyme losses due to lignin binding can be modulated by using different enzymes of the same activity We used water:dioxane (1:9) to extract lignin from pretreated corn stover. Commercial cellulases were incubated with lignin and the unbound supernatants were evaluated for individual enzyme loss by SDS=PAGE and these were correlated with activity loss using various pNP-sugar substrates. Colorimetric assays for general glycosyl hydrolase activities showed distinct differences in enzyme binding to lignin for each enzyme activity. Native systems demonstrated low binding of endo- and exo-cellulases, high binding of xylanase, and moderate ..beta..-glucosidase binding. Engineered cellulase mixtures exhibited low binding of exo-cellulases, very strong binding of endocellulases and ..beta..- glucosidase, and mixed binding of xylanase activity. The augmented cellulase had low binding of exocellulase, high binding of endocellulase and xylanase, and moderate binding of ..beta..-glucosidase activities. Bound and unbound activities were correlated with general molecular weight ranges of proteins as measured by loss of proteins bands in bound fractions on SDS-PAGE gels. Lignin-bound high molecular weight bands correlated with binding of ..beta..-glucosidase activity. While ..beta..-glucosidases demonstrated high binding in many cases, they have been shown to remain active. Bound low molecular weight bands correlated with xylanase activity binding. Contrary to other literature, exocellulase activity did not show strong lignin binding. The variation in enzyme activity binding between the three classes of cellulases preparations indicate that it is certainly possible to alter the binding of specific

  5. Characterization of food-grade titanium dioxide: the presence of nanosized particles.

    Science.gov (United States)

    Yang, Yu; Doudrick, Kyle; Bi, Xiangyu; Hristovski, Kiril; Herckes, Pierre; Westerhoff, Paul; Kaegi, Ralf

    2014-06-03

    Titanium dioxide (TiO2) is widely used in food products, which will eventually enter wastewater treatment plants and terrestrial or aquatic environments, yet little is known about the fraction of this TiO2 that is nanoscale, or the physical and chemical properties of TiO2 that influence its human and environmental fate or toxicity. Instead of analyzing TiO2 properties in complex food or environmental samples, we procured samples of food-grade TiO2 obtained from global food suppliers and then, using spectroscopic and other analytical techniques, quantified several parameters (elemental composition, crystal structure, size, and surface composition) that are reported to influence environmental fate and toxicity. Another sample of nano-TiO2 that is generally sold for catalytic applications (P25) and widely used in toxicity studies, was analyzed for comparison. Food-grade and P25 TiO2 are engineered products, frequently synthesized from purified titanium precursors, and not milled from bulk scale minerals. Nanosized materials were present in all of the food-grade TiO2 samples, and transmission electron microscopy showed that samples 1-5 contained 35, 23, 21, 17, and 19% of nanosized primary particles (average hydrodynamic diameter of >100 nm. Food-grade samples contained phosphorus (P), with concentrations ranging from 0.5 to 1.8 mg of P/g of TiO2. The phosphorus content of P25 was below inductively coupled plasma mass spectrometry detection limits. Presumably because of a P-based coating detected by X-ray photoelectron spectroscopy, the ζ potential of the food-grade TiO2 suspension in deionized water ranged from -10 to -45 mV around pH 7, and the iso-electric point for food-grade TiO2 (grade materials, and although the presence of amorphous TiO2 could not be ruled out, it is unlikely on the basis of Raman analysis. The food-grade TiO2 was solar photoactive. Cationic dyes adsorbed more readily to food-grade TiO2 than P25, indicating very different potentials for

  6. Rapid preparation of functional polysaccharides from Pyropia yezoensis by microwave-assistant rapid enzyme digest system.

    Science.gov (United States)

    Lee, Ji-Hyeok; Kim, Hyung-Ho; Ko, Ju-Young; Jang, Jun-Ho; Kim, Gwang-Hoon; Lee, Jung-Suck; Nah, Jae-Woon; Jeon, You-Jin

    2016-11-20

    This study describes a simple preparation of functional polysaccharides from Pyropia yezoensis using a microwave-assistant rapid enzyme digest system (MAREDS) with various carbohydrases, and evaluates their antioxidative effects. Polysaccharide hydrolysates were prepared using MAREDS under different hydrolytic conditions of the carbohydrases and microwave powers. Polysaccharides less than 10kDa (Low molecular weight polysaccharides, LMWP, ≤10kDa) were efficiently obtained using an ultrafiltration (molecular weight cut-off of 10kDa). MAREDS increases AMG activation via an increased degree of hydrolysis; the best AMG hydrolysate was prepared using a 10:1 ratio of substrate to enzyme for 2h in MAREDS with 400W. LMWP consisted of galactose (27.3%), glucose (64.5%), and mannose (8.3%) from the AMG hydrolysate had stronger antioxidant effects than the high molecular weight polysaccharides (>10kDa). We rapidly prepared functional LMWPs by using MAREDS with carbohydrases, and suggest that LMWP might be potentially a valuable algal polysaccharide antioxidant. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Use of the alr gene as a food-grade selection marker in lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Benchimol, M.G.; Lambert, J.; Palumbo, E.; Deghorain, M.; Delcour, J.; Vos, de W.M.; Kleerebezem, M.; Hols, P.

    2002-01-01

    Both Lactococcus lactis and Lactobacillus plantarum contain a single alr gene, encoding an alanine racemase (EC 5.1.1.1), which catalyzes the interconversion of D-alanine and L-alanine. The alr genes of these lactic acid bacteria were investigated for their application as food-grade selection

  8. Food-grade Pickering stabilisation of foams by in situ hydrophobisation of calcium carbonate particles

    NARCIS (Netherlands)

    Binks, Bernard P.; Muijlwijk, K.; Koman, Henriëtte; Poortinga, A.T.

    2017-01-01

    The aim of this study was to investigate the possibility of stabilising foam bubbles in water by adsorption of calcium carbonate (CaCO3) particles. Because CaCO3 is hydrophilic and not surface-active, particles were hydrophobised in situ with several emulsifiers. The used emulsifiers were food-grade

  9. Food-grade pickering stabilisation of foams by in situ hydrophobisation of calcium carbonate particles

    NARCIS (Netherlands)

    Binks, B.P.; Muijlwijk, K.; Koman, H.; Poortinga, A.T.

    2017-01-01

    The aim of this study was to investigate the possibility of stabilising foam bubbles in water by adsorption of calcium carbonate (CaCO3) particles. Because CaCO3 is hydrophilic and not surface-active, particles were hydrophobised in situ with several emulsifiers. The used emulsifiers were food-grade

  10. Construction of a food-grade multiple-copy integration system for Lactococcus lactis

    NARCIS (Netherlands)

    Leenhouts, K.; Bolhuis, A.; Venema, G.; Kok, J.

    A food-grade vector system was developed that allows stable integration of multiple plasmid copies in the chromosome of Lactococcus lactis. The vector consists of the plus origin of replication (Ori(+)) of the lactococcal plasmid pWV01, the sucrose genes of the lactic acid bacterium Pediococcus

  11. Mineral content in grains of seven food-grade sorghum hybrids grown in Mediterranean environment

    Science.gov (United States)

    Sorghum is a major crop used for food, feed and industrial purposes worldwide. The objective of this study was to determine the mineral content in grains of seven white food-grade sorghum hybrids bred and adapted for growth in the central USA and grown in a Mediterranean area of Southern Italy. The ...

  12. Protein Hydrolysis from Catfish Prepared by Papain Enzyme and Antioxidant Activity of Hydrolyzate

    Directory of Open Access Journals (Sweden)

    Ace Baehaki

    2015-12-01

    Full Text Available The objective of this research was to make a protein hydrolysates from catfish (Pangasius pangasius enzymatically using papain enzyme and analyzed the antioxidant activity of protein hydrolysates produced. The research used the method completely randomized design with two replications the treatment were the difference concentration of the papain enzyme (0%, 1%, 2%, 3%, 4%, 5%, and 6%. The parameters of research were antioxidative activity using DPPH (2,2-difenil-1–pikrilhidrazil, protein content, and molecular weight using SDS-PAGE (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis. The results showed that catfish protein hydrolysates prepared by papain enzyme has antioxidative activity. The highest degree of hydrolysis was 71.98% at enzyme concentration of 6%. Based on the DPPH scavenging method catfish protein hydrolysates has the antioxidative activity with the value 37.85-67.62%. The protein content of catfish protein hydrolysates were 20.86-54.47 mg/ml. The molecular weight of catfish protein hydrolyzates were 11.90-65.20 kDa.

  13. Food processing: The use of non-fouling food grade heat transfer fluids

    International Nuclear Information System (INIS)

    Wright, Christopher Ian; Bembridge, Thomas; Picot, Eole; Premel, Julien

    2015-01-01

    It is reported that there are some 4000 companies operating high temperature thermal fluid systems in the UK and Ireland. This excludes steam or water based systems. The heat transfer fluids (HTFs) used in food processing are highly refined mineral HTFs that are non-toxic, non-irritating and lack an odour. If an HTF has been certified for use in food processing it carries an HT-1 certificate. HTFs suitable for use in food processing are commonly referred to as ‘non-fouling’ which means as they thermally degrade they produce small carbon particles that are suspended in the HTF. Moreover, the carbon formations are less sticky and this reduces the extent of adhesion to the internal surfaces of an HTF system. The current paper analysed the test reports from 1223 HTF systems and showed that, on average, the carbon residue for food grade HTF was lower than non-food grade HTF. This clearly demonstrates what the non-fouling nature of a food grade HTF. This paper then explored the regulatory, legal and environmental landscape for food grade HTFs. In this area of manufacturing, it is critical that the HTFs used are suitable for incidental contact with food. Other measures put consumer safety at the heart of all operations (i.e., internal company procedures such as hazard analysis and critical control points [HACCP]) and that food is safe for consumer consumption (e.g., external controls such as auditing manufacturers to ensure good quality and distribution practice). The authors introduce the idea that safety could be further enhanced through independent HTF sampling and chemical analysis of HTFs to ensure they are food grade and should be done without any interruption to a manufacturer's production. - Highlights: • Food grade heat transfer fluid (HTF) is colourless, non-toxic and non-irritating. • This HTF is non-fouling and less carbon forms. • Such HTFs can be safely used in food processing if they are HT-1 certified. • A number of controls (e.g., HACCP

  14. The use of combined radiation methods for decreasing the bacterial dissemination of enzyme preparations

    International Nuclear Information System (INIS)

    Samojlenko, I.I.; Fedotov, N.S.; Tumanyan, M.A.; Korolev, N.I.

    1984-01-01

    A study was made on possibility of using ionizing radiation in combination with alternative magnetic field (AMF) and heating for decreasing the bacterial dissemination of proteolytic enzymes. Papain, trypsin, chymotrypsin and amylorysin (the preparation possessing proteolytic and amylolytic activities) were subjected to gamma irradiation at 10-25 kGy dose range, the effect of AMF with 750 oe and heating at 50 deg during 60 min. Model tests conducted with the use of Escherichia Coli cells and Bacillus anthracoides spores showed that survival rate of bacteria irradiated in protective medium was lower in the case of combined magnetoradiation and thermoradiation effect. The use of 10 kGy dose of ionizing radiation in combination with treatment in alternative magnetic field or with heating provided the required decrease of dissemination of irradiated enzyme samples with complete conservation of proteolytic activity by them

  15. Modulation of liver enzymes by an Iranian preparation of Echinacea purpurea

    Directory of Open Access Journals (Sweden)

    A. Manayi

    2015-10-01

    Full Text Available Hepatitis B, a common infectious disease of liver, is transmitted by blood and body fluids like semen and vaginal fluid that carry hepatitis B virus (HBV.  In chronic infection, medical care is required to decrease possibility of cirrhosis and liver cancer. In the present report, the hepatoprotective effect of an Echinacea purpurea preparation (Echiherb® has been described in a patient who suffered from HBV infection. The levels of both enzymes of aspartate aminotransferase (AST and alanine aminotransferase (ALT decreased to their normal level after 6 weeks of treatment. Therefore, this report may provide a new perspective for protection of liver in patients with HBV infection along with other diseases which damage liver cells using E. purpurea preparations.

  16. Method of preparing highly active and thermostable preparations of liver uridin-kinase usable for enzymic synthesis of radioactive nucleoside-5'-phosphates

    International Nuclear Information System (INIS)

    Cihak, A.; Vesely, J.

    1975-01-01

    A method is described of preparing a high-activity uridine kinase for the enzymic synthesis of radioactive nucleoside-5m-phosphates of the pyrimidine series. The preparation is separated from male rat liver after intraperitoneal application of 5'-azacytidine. Examples are given showing detailed procedures for the conversion of uridine and 6-azauridine to the corresponding 5'-phosphates. (L.K.)

  17. [Screening of food-grade microorganisms for biotransformation of D-tagatose and cloning and expression of L-arabinose isomerase].

    Science.gov (United States)

    Men, Yan; Zhu, Yueming; Guan, Yuping; Zhang, Tongcun; Izumori, Ken; Sun, Yuanxia

    2012-05-01

    L-Arabinose isomerase (L-AI) is an intracellular enzyme that catalyzes the reversible isomerization of D-galactose and D-tagatose. Given the widespread use of D-tagatose in the food industry, food-grade microorganisms and the derivation of L-AI for the production of D-tagatose is gaining increased attention. In the current study, food-grade strains from different foods that can convert D-galactose to D-tagatose were screened. According to physiological, biochemical, and 16S rDNA gene analyses, the selected strain was found to share 99% identity with Pediococcus pentosaceus, and was named as Pediococcus pentosaceus PC-5. The araA gene encoding L-AI from Pediococcus pentosaceus PC-5 was cloned and overexpressed in E. coli BL21. The yield of D-tagatose using D-galactose as the substrate catalyzed by the crude enzyme in the presence of Mn2+ was found to be 33% at 40 degrees C.

  18. A general method for selection of riboflavin-overproducing food grade micro-organisms

    OpenAIRE

    Burgess, Catherine M; Smid, Eddy J; Rutten, Ger; van Sinderen, Douwe

    2006-01-01

    Abstract Background This study describes a strategy to select and isolate spontaneous riboflavin-overproducing strains of Lactobacillus (Lb.) plantarum, Leuconostoc (Lc.) mesenteroides and Propionibacterium (P.) freudenreichii. Results The toxic riboflavin analogue roseoflavin was used to isolate natural riboflavin-overproducing variants of the food grade micro-organisms Lb. plantarum, Lc. mesenteroides and P. freudenreichii strains. The method was successfully employed for strains of all thr...

  19. Food grade titanium dioxide disrupts intestinal brush border microvilli in vitro independent of sedimentation.

    Science.gov (United States)

    Faust, James J; Doudrick, Kyle; Yang, Yu; Westerhoff, Paul; Capco, David G

    2014-06-01

    Bulk- and nano-scale titanium dioxide (TiO2) has found use in human food products for controlling color, texture, and moisture. Once ingested, and because of their small size, nano-scale TiO2 can interact with a number of epithelia that line the human gastrointestinal tract. One such epithelium responsible for nutrient absorption is the small intestine, whose constituent cells contain microvilli to increase the total surface area of the gut. Using a combination of scanning and transmission electron microscopy it was found that food grade TiO2 (E171 food additive coded) included ∼25% of the TiO2 as nanoparticles (NPs; TiO2 sedimentation. It was found that TiO2 isolated from the candy coating of chewing gum and a commercially available TiO2 food grade additive samples were of the anatase crystal structure. Exposure to food grade TiO2 additives, containing nanoparticles, at the lowest concentration tested within this experimental paradigm to date at 350 ng/mL (i.e., 100 ng/cm(2) cell surface area) resulted in disruption of the brush border. Through the use of two independent techniques to remove the effects of gravity, and subsequent TiO2 sedimentation, it was found that disruption of the microvilli was independent of sedimentation. These data indicate that food grade TiO2 exposure resulted in the loss of microvilli from the Caco-2BBe1 cell system due to a biological response, and not simply a physical artifact of in vitro exposure.

  20. A Food-Grade Cloning System for Industrial Strains of Lactococcus lactis

    Science.gov (United States)

    Sørensen, Kim I.; Larsen, Rasmus; Kibenich, Annette; Junge, Mette P.; Johansen, Eric

    2000-01-01

    We have previously reported the construction of a food-grade cloning vector for Lactococcus using the ochre suppressor, supB, as the selective marker. This vector, pFG1, causes only a slight growth inhibition in the laboratory strain MG1363 but is unstable in the industrial strains tested. As supB suppresses both amber and ochre stop codons, which are present in 82% of all known lactococcal genes, this undesirable finding may result from the accumulation of elongated mistranslated polypeptides. Here, we report the development of a new food-grade cloning vector, pFG200, which is suitable for overexpressing a variety of genes in industrial strains of Lactococcus lactis. The vector uses an amber suppressor, supD, as selectable marker and consists entirely of Lactococcus DNA, with the exception of a small polylinker region. Using suppressible pyrimidine auxotrophs, selection and maintenance are efficient in any pyrimidine-free medium including milk. Importantly, the presence of this vector in a variety of industrial strains has no significant effect on the growth rate or the rate of acidification in milk, making this an ideal system for food-grade modification of industrially relevant L. lactis strains. The usefulness of this system is demonstrated by overexpressing the pepN gene in a number of industrial backgrounds. PMID:10742196

  1. Systematic study on the preparation of a food grade soybean protein

    Energy Technology Data Exchange (ETDEWEB)

    Bazinet, L.; Labrecque, R.; Toupin, R. [Institut de Recherche d`Hydro-Quebec, Varennes, PQ (Canada); Boulet, M.; Ippersiel, D.; Lamarche, F. [Food Research and Development Centre, St. Hyacinthe, PQ (Canada)

    1996-05-01

    A new application of electrodialysis for the precipitation and separation of soy proteins, called electro-acidification, was evaluated. The compositional properties of electro-acidified proteins were compared to those of commercial standards. Since protein solutions have physico-chemical properties that make their behaviour difficult to predict, the limiting current, and the factors which influence them, were determined. These factors included KCl concentration, protein concentration, the recirculation rate in the stack, the concentration of added salt and the temperature of the protein solution. Three approaches to electro-acidification were developed, i. e., bipolar-membrane (most rapid with the lowest energy consumption), alternating anionic and cationic membranes (most time-consuming), and anodic proton generation (intermediate between the other two). The compositional quality of electro-acidified samples was shown to be superior or equal to that of commercial standards as confirmed by the solubility profile of the products. It was therefore concluded that using electrodialysis to produce protein isolates was technologically feasible and energy efficient. 76 refs., 4 tabs., 33 figs.

  2. Assessment of Dextran Antigenicity of Intravenous Iron Preparations with Enzyme-Linked Immunosorbent Assay (ELISA).

    Science.gov (United States)

    Neiser, Susann; Koskenkorva, Taija S; Schwarz, Katrin; Wilhelm, Maria; Burckhardt, Susanna

    2016-07-21

    Intravenous iron preparations are typically classified as non-dextran-based or dextran/dextran-based complexes. The carbohydrate shell for each of these preparations is unique and is key in determining the various physicochemical properties, the metabolic pathway, and the immunogenicity of the iron-carbohydrate complex. As intravenous dextran can cause severe, antibody-mediated dextran-induced anaphylactic reactions (DIAR), the purpose of this study was to explore the potential of various intravenous iron preparations, non-dextran-based or dextran/dextran-based, to induce these reactions. An IgG-isotype mouse monoclonal anti-dextran antibody (5E7H3) and an enzyme-linked immunosorbent assay (ELISA) were developed to investigate the dextran antigenicity of low molecular weight iron dextran, ferumoxytol, iron isomaltoside 1000, ferric gluconate, iron sucrose and ferric carboxymaltose, as well as isomaltoside 1000, the isolated carbohydrate component of iron isomaltoside 1000. Low molecular weight iron dextran, as well as dextran-based ferumoxytol and iron isomaltoside 1000, reacted with 5E7H3, whereas ferric carboxymaltose, iron sucrose, sodium ferric gluconate, and isolated isomaltoside 1000 did not. Consistent results were obtained with reverse single radial immunodiffusion assay. The results strongly support the hypothesis that, while the carbohydrate alone (isomaltoside 1000) does not form immune complexes with anti-dextran antibodies, iron isomaltoside 1000 complex reacts with anti-dextran antibodies by forming multivalent immune complexes. Moreover, non-dextran based preparations, such as iron sucrose and ferric carboxymaltose, do not react with anti-dextran antibodies. This assay allows to assess the theoretical possibility of a substance to induce antibody-mediated DIARs. Nevertheless, as this is only one possible mechanism that may cause a hypersensitivity reaction, a broader set of assays will be required to get an understanding of the mechanisms that may

  3. Preparation and Characterization of Enzyme Compartments in UV-Cured Polyurethane-Based Materials and Their Application in Enzymatic Reactions

    Directory of Open Access Journals (Sweden)

    Diana Uhrich

    2017-11-01

    Full Text Available The preparation and characterization of UV-cured polyurethane-based materials for the mild inclusion immobilization of enzymes was investigated. Full curing of the polymer precursor/enzyme solution mixture was realized by a short irradiation with UV-light at ambient temperatures. The included aqueous enzyme solution remains highly dispersed in the polymer material with an even size distribution throughout the polymer material. The presented concept provides stable enzyme compartments which were applied for an alcohol dehydrogenase-catalyzed reduction reaction in organic solvents. Cofactor regeneration was achieved by a substrate-coupled approach via 2-propanol or an enzyme-coupled approach by a glucose dehydrogenase. This reaction concept can also be used for a simultaneous application of contrary biocatalytic reaction conditions within an enzymatic cascade reaction. Independent polymer-based reaction compartments were provided for two incompatible enzymatic reaction systems (alcohol dehydrogenase and hydroxynitrile lyase, while the relevant reactants diffuse between the applied compartments.

  4. Preparation of crosslinked enzyme aggregates (CLEAs) of acid urease with urethanase activity and their application.

    Science.gov (United States)

    Zhang, Qian; Zha, Xiaohong; Zhou, Nandi; Tian, Yaping

    2016-04-01

    An acid urease from Providencia rettgeri JN-B815 was purified via ultrasonication, ethanol precipitation, and DEAE ion-exchange column chromatography. It was found that the enzyme exhibits not only urease activity, but also urethanase activity, which made it possible to reduce EC already existed or would produce and its precursor urea at the same time. Then, crosslinked enzyme aggregates of P. rettgeri urease (PRU-CLEAs) were prepared using genipin as crosslinking agent. The purification process of acid urease, the effects of genipin concentration, and crosslinking time on PRU-CLEAs activity were investigated. The crosslinking was performed at pH 4.5 for 2.5 h, using 0.3% genipin as crosslinking agent, and 0.3 g · L(-1) bovine serum albumin as protein feeder. Using the obtained PRU-CLEAs, the removal rate of urea was up to 9.31 mg · L(-1) · h(-1). The removal rate of urea was still up to 7.56 mg · L(-1) · h(-1) after PRU-CLEAs was re-used for 6 times. When PRU-CLEAs were applied in a batch stirred and membrane reactor, the removal rate of urea in rice wine reached 5.16 mg · L(-1) · h(-1) and the removal rate of EC was 9.21 μg · L(-1) · h(-1). Furthermore, the treatment with PRU-CLEAs revealed no significant change of volatile flavor substances in Chinese rice wine. Thus PRU-CLEAs have great potential in the elimination of EC in Chinese rice wine. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Using an Inducible Promoter of a Gene Encoding Penicillium verruculosum Glucoamylase for Production of Enzyme Preparations with Enhanced Cellulase Performance.

    Directory of Open Access Journals (Sweden)

    Alexander G Bulakhov

    Full Text Available Penicillium verruculosum is an efficient producer of highly active cellulase multienzyme system. One of the approaches for enhancing cellulase performance in hydrolysis of cellulosic substrates is to enrich the reaction system with β -glucosidase and/or accessory enzymes, such as lytic polysaccharide monooxygenases (LPMO displaying a synergism with cellulases.Genes bglI, encoding β-glucosidase from Aspergillus niger (AnBGL, and eglIV, encoding LPMO (formerly endoglucanase IV from Trichoderma reesei (TrLPMO, were cloned and expressed by P. verruculosum B1-537 strain under the control of the inducible gla1 gene promoter. Content of the heterologous AnBGL in the secreted multienzyme cocktails (hBGL1, hBGL2 and hBGL3 varied from 4 to 10% of the total protein, while the content of TrLPMO in the hLPMO sample was ~3%. The glucose yields in 48-h hydrolysis of Avicel and milled aspen wood by the hBGL1, hBGL2 and hBGL3 preparations increased by up to 99 and 80%, respectively, relative to control enzyme preparations without the heterologous AnBGL (at protein loading 5 mg/g substrate for all enzyme samples. The heterologous TrLPMO in the hLPMO preparation boosted the conversion of the lignocellulosic substrate by 10-43%; however, in hydrolysis of Avicel the hLPMO sample was less effective than the control preparations. The highest product yield in hydrolysis of aspen wood was obtained when the hBGL2 and hLPMO preparations were used at the ratio 1:1.The enzyme preparations produced by recombinant P. verruculosum strains, expressing the heterologous AnBGL or TrLPMO under the control of the gla1 gene promoter in a starch-containing medium, proved to be more effective in hydrolysis of a lignocellulosic substrate than control enzyme preparations without the heterologous enzymes. The enzyme composition containing both AnBGL and TrLPMO demonstrated the highest performance in lignocellulose hydrolysis, providing a background for developing a fungal strain capable

  6. Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads.

    Science.gov (United States)

    Thompson, Benjamin R; Horozov, Tommy S; Stoyanov, Simeon D; Paunov, Vesselin N

    2017-08-01

    We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a slurry of hydrogel microbeads. The pancake batter was mixed with a controlled volume percentage of slurry of hydrogel beads and cooked. From bomb calorimetry experiments, the composites were found to have a reduced caloric density that reflects the volume percentage of hydrogel beads mixed with the batter. Using this procedure, we were able to reduce the caloric density of pancakes by up to 23 ± 3% when the volume percentage of hydrogel beads initially used was 25%. The method is not limited to pancakes and could potentially be applied to various other food products. The structure and morphology of the freeze-dried pancakes and pancake-hydrogel composites were investigated and pores of a similar size to the hydrogel beads were found, confirming that the gel beads maintained their structure during the cooking process. There is scope for further development of this method by the encapsulation of nutritionally beneficial or flavour enhancing ingredients within the hydrogel beads.

  7. A Food-Grade Cloning System for Industrial Strains of Lactococcus lactis

    OpenAIRE

    Sørensen, Kim I.; Larsen, Rasmus; Kibenich, Annette; Junge, Mette P.; Johansen, Eric

    2000-01-01

    We have previously reported the construction of a food-grade cloning vector for Lactococcus using the ochre suppressor, supB, as the selective marker. This vector, pFG1, causes only a slight growth inhibition in the laboratory strain MG1363 but is unstable in the industrial strains tested. As supB suppresses both amber and ochre stop codons, which are present in 82% of all known lactococcal genes, this undesirable finding may result from the accumulation of elongated mistranslated polypeptide...

  8. Novel regenerative large-volume immobilized enzyme reactor: preparation, characterization and application.

    Science.gov (United States)

    Ruan, Guihua; Wei, Meiping; Chen, Zhengyi; Su, Rihui; Du, Fuyou; Zheng, Yanjie

    2014-09-15

    A novel large-volume immobilized enzyme reactor (IMER) on small column was prepared with organic-inorganic hybrid silica particles and applied for fast (10 min) and oriented digestion of protein. At first, a thin enzyme support layer was formed in the bottom of the small column by polymerization with α-methacrylic acid and dimethacrylate. After that, amino SiO2 particles was prepared by the sol-gel method with tetraethoxysilane and 3-aminopropyltriethoxysilane. Subsequently, the amino SiO2 particles were activated by glutaraldehyde for covalent immobilization of trypsin. Digestive capability of large-volume IMER for proteins was investigated by using bovine serum albumin (BSA), cytochrome c (Cyt-c) as model proteins. Results showed that although the sequence coverage of the BSA (20%) and Cyt-c (19%) was low, the large-volume IMER could produce peptides with stable specific sequence at 101-105, 156-160, 205-209, 212-218, 229-232, 257-263 and 473-451 of the amino sequence of BSA when digesting 1mg/mL BSA. Eight of common peptides were observed during each of the ten runs of large-volume IMER. Besides, the IMER could be easily regenerated by reactivating with GA and cross-linking with trypsin after breaking the -C=N- bond by 0.01 M HCl. The sequence coverage of BSA from regenerated IMER increased to 25% comparing the non-regenerated IMER (17%). 14 common peptides. accounting for 87.5% of first use of IMER, were produced both with IMER and regenerated IMER. When the IMER was applied for ginkgo albumin digestion, the sequence coverage of two main proteins of ginkgo, ginnacin and legumin, was 56% and 55%, respectively. (Reviewer 2) Above all, the fast and selective digestion property of the large-volume IMER indicated that the regenerative IMER could be tentatively used for the production of potential bioactive peptides and the study of oriented protein digestion. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. A Biocatalytic One-Pot Approach for the Preparation of Lignin Oligomers Using an Oxidase/Peroxidase Cascade Enzyme System

    NARCIS (Netherlands)

    Habib, Mohamed H. M.; Deuss, Peter J.; Loncar, Nikola; Trajkovic, Milos; Fraaije, Marco W.

    2017-01-01

    Synthetic lignin was prepared biocatalytically in a one-pot, two-step reaction using an oxidase/peroxidase cascade enzyme system. Using eugenol in combination with eugenol oxidase and a peroxidase, lignin-like material was produced. The cascade reaction takes advantage of the ability of the oxidase

  10. Preparation of salted meat products, e.g. cured bacon - by injecting liquid comprising meat proteins hydrolysed with enzymes

    DEFF Research Database (Denmark)

    1997-01-01

    Preparation of salted meat products comprises the following:(1) meat is chopped into fine pieces and mixed with water to form a slurry; (2) enzymes hydrolyse proteins in the meat; (3) adding a culture to the resulting medium, which comprises short peptide chains or amino acids; (4) forming...... flavourings as the culture is growing, and (5) injecting the liquid into pieces of meat....

  11. Preparation and Analysis of N-Terminal Chemokine Receptor Sulfopeptides Using Tyrosylprotein Sulfotransferase Enzymes.

    Science.gov (United States)

    Seibert, Christoph; Sanfiz, Anthony; Sakmar, Thomas P; Veldkamp, Christopher T

    2016-01-01

    In most chemokine receptors, one or multiple tyrosine residues have been identified within the receptor N-terminal domain that are, at least partially, modified by posttranslational tyrosine sulfation. For example, tyrosine sulfation has been demonstrated for Tyr-3, -10, -14, and -15 of CCR5, for Tyr-3, -14, and -15 of CCR8, and for Tyr-7, -12, and -21 of CXCR4. While there is evidence for several chemokine receptors that tyrosine sulfation is required for optimal interaction with the chemokine ligands, the precise role of tyrosine sulfation for chemokine receptor function remains unclear. Furthermore, the function of the chemokine receptor N-terminal domain in chemokine binding and receptor activation is also not well understood. Sulfotyrosine peptides corresponding to the chemokine receptor N-termini are valuable tools to address these important questions both in structural and functional studies. However, due to the lability of the sulfotyrosine modification, these peptides are difficult to obtain using standard peptide chemistry methods. In this chapter, we provide methods to prepare sulfotyrosine peptides by enzymatic in vitro sulfation of peptides using purified recombinant tyrosylprotein sulfotransferase (TPST) enzymes. In addition, we also discuss alternative approaches for the generation of sulfotyrosine peptides and methods for sulfopeptide analysis. © 2016 Elsevier Inc. All rights reserved.

  12. Extraction of erythrocyte enzymes for the preparation of polyhemoglobin-catalase-superoxide dismutase.

    Science.gov (United States)

    Gu, Jingsong; Chang, Thomas Ming Swi

    2009-01-01

    In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study on extracting these enzymes from red blood cells and analyzing the amount of enzymes needed for adequate protection from ischemia-reperfusion.

  13. Pharmaceutical/food grade titanium dioxide particles are absorbed into the bloodstream of human volunteers.

    Science.gov (United States)

    Pele, Laetitia C; Thoree, Vinay; Bruggraber, Sylvaine F A; Koller, Dagmar; Thompson, Richard P H; Lomer, Miranda C; Powell, Jonathan J

    2015-09-02

    Exposure to persistent engineered nano and micro particles via the oral route is well established. Animal studies have demonstrated that, once ingested, a small proportion of such particles translocate from the gastrointestinal tract to other tissues. Exposure to titanium dioxide is widespread via the oral route, but only one study has provided indirect evidence (total titanium analyses) of absorption into the blood stream in humans. We sought to replicate these observations and to provide additional evidence for particulate uptake. Human volunteers with normal intestinal permeability were orally administered 100 mg pharmaceutical/food grade titanium dioxide. Blood samples were collected from 0.5 to 10 h post ingestion and analysed for the presence of reflectant bodies (particles) by dark field microscopy, and for total titanium by inductively coupled plasma mass spectrometry (ICP-MS). Blood film analyses implied early absorption of particles (2 h) with a peak maximum at 6 h following ingestion. The presence of these reflectant particles in blood roughly mirrored the levels of total titanium by ICP-MS, providing good evidence for the latter being a measure of whole particle (titanium dioxide) absorption. This study shows that a fraction of pharmaceutical/food grade titanium dioxide is absorbed systemically by humans following ingestion. It confirms that at least two routes of particle uptake may exist in the human gut- one proximal and one distal. Further work should quantify human exposure and uptake of such persistent particles.

  14. Food Grade Ehanol Production With Fermentation And Distillation Process Using Stem Sorghum

    Directory of Open Access Journals (Sweden)

    Yuliana Setyowati

    2015-03-01

    Full Text Available 10% -12% of sugar in its stem which is the optimum sugar concentration in fermentation process for bioethanol production. Sorghum has a high potential to be developed as a raw material for food-grade ethanol production which can be used to support food-grade ethanol demand in Indonesia through a fermentation process. This research focused on the effect of microorganism varieties in the fermentation process which are mutant Zymomonas mobilis (A3, Saccharomyces cerevisiae and Pichia stipitis mixture. The Research for purification process are separated into two parts, distillation with steel wool structured packing and dehydration process using molecular sieve and eliminating impurities using activated carbon. The research can be concluded that the best productivity shown in continuous fermentation in the amount of 84.049 (g / L.hr using the mixture of Saccharomyces cerevisiae and Pichia stipitis. The highest percentage of ethanol yield produced in batch fermentation using the mixture of Saccharomyces cerevisiae and Pichia stipitis that is equal to 51.269%. And for the adsorption, the best result shown in continuous fermentation by using Zymomonas Mobilis of 88.374%..

  15. Current status and emerging role of glutathione in food grade lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Pophaly Sarang

    2012-08-01

    Full Text Available Abstract Lactic acid bacteria (LAB have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms.

  16. 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.

  17. Studies on the preparation of immobilized enzymes by radio-polymerization, 10

    International Nuclear Information System (INIS)

    Amarakone, S.P.; Hayashi, Toru; Kawashima, Koji.

    1983-01-01

    β-Galactosidase of E. coli origin was immobilized in the form of beads by the radiopolymerization of different combinations of monomers using a gamma irradiation technique. With the dialysed enzyme, recoveries of over 300 % could be obtained on suitable monomer combinations containing magnesium and sodium acrylates. The recovery of the enzyme also depended on the irradiation time. The immobilized enzyme had better pH and temperature stability and was less affected by the presence of metal ions in the medium, compared to the native enzyme. The optimum pH and temperatures of the immobilized enzyme were different from those of the native enzyme and were 7.0 to 7.5 and 50 deg C respectively. The immobilized enzyme was used in a column for the continuous determination of lactose with a standard type autoanalyser. Good linearity could be observed even up to 3 % lactose in the sample. (author)

  18. The acid tolerant L-arabinose isomerase from the food grade Lactobacillus sakei 23K is an attractive D-tagatose producer.

    Science.gov (United States)

    Rhimi, Moez; Ilhammami, Rimeh; Bajic, Goran; Boudebbouze, Samira; Maguin, Emmanuelle; Haser, Richard; Aghajari, Nushin

    2010-12-01

    The araA gene encoding an L-arabinose isomerase (L-AI) from the psychrotrophic and food grade Lactobacillus sakei 23K was cloned, sequenced and over-expressed in Escherichia coli. The recombinant enzyme has an apparent molecular weight of nearly 220 kDa, suggesting it is a tetramer of four 54 kDa monomers. The enzyme is distinguishable from previously reported L-AIs by its high activity and stability at temperatures from 4 to 40 degrees C, and pH from 3 to 8, and by its low metal requirement of only 0.8 mM Mn(2+) and 0.8 mM Mg(2+) for its maximal activity and thermostability. Enzyme kinetic studies showed that this enzyme displays a high catalytic efficiency allowing D-galactose bioconversion rates of 20% and 36% at 10 and 45 degrees C, respectively, which are useful for commercial production of D-tagatose. 2010 Elsevier Ltd. All rights reserved.

  19. Extraction of Erythrocyte Enzymes for the Preparation of Polyhemoglobin-catalase-superoxide Dismutase

    OpenAIRE

    Gu, Jingsong; Chang, Thomas Ming Swi

    2009-01-01

    In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study ...

  20. Perfusion chromatography separation of the tomato fruit-specific pectin methylesterase from a semipurified commercial enzyme preparation.

    Science.gov (United States)

    Savary, B J

    2001-08-01

    A rapid and simple method was developed, using perfusion chromatography media, to separate the fruit-specific pectin methylesterase (PME) isoform from the depolymerizing enzyme polygalacturonase (PG) and other contaminating pectinases present in a commercial tomato enzyme preparation. Pectinase activities were adsorbed onto a Poros HS (a strong cation exchanger) column in 20 M HEPES buffer at pH 7.5. The fruit-specific PME was eluted from the column with 80 mM NaCl, followed by a step to 300 mM NaCl to elute PG activity. Rechromatography of the PME activity peak with a linear gradient further resolved two PME isoenzymes and removed residual traces of PG activity. The PG activity peak was further treated with lectin affinity chromatography to provide purified PG enzyme, which was separated from a salt-dependent PME (tentatively identified as a "ubiquitous-type" isoform), and a pectin acetylesterase. The later enzyme has not been reported previously in tomato. This method provides monocomponent enzymes that will be useful for studying enzyme mechanisms and for modifying pectin structure and functional properties.

  1. Food grade microemulsion systems: canola oil/lecithin:n-propanol/water.

    Science.gov (United States)

    Abbasi, Soleiman; Radi, Mohsen

    2016-03-01

    In this study, the capability of a natural surfactant, lecithin, and the influence of ionic strength, pH, and temperature on some properties of a food grade microemulsion system were evaluated. For this purpose, the pseudoternary phase diagrams of canola oil/lecithin:n-propanol/water microemulsions in the presence of different salts (NaCl and CaCl2), ionic strengths, pHs, and temperatures were constructed. Our findings showed that the presence of salts slightly increased the W/O areas on the phase diagrams, whereas pH variation was not effective on the microemulsion formation. The expansion of microemulsion areas with temperature indicated the greater triglycerides solubilization capacity of lecithin based microemulsions at higher temperatures. These findings revealed the efficiency of lecithin-based microemulsion system for solubilization of triglycerides which can potentially be used for extraction of edible vegetable oils particularly canola oil. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Preparation and evaluation of a coumarin library towards the inhibitory activity of the enzyme gGAPDH from Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Alvim Junior, Joel; Dias, Ricardo L.A.; Correa, Arlene G. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Quimica]. E-mail: agcorrea@power.ufscar.br; Castilho, Marcelo S.; Oliva, Glaucius [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica

    2005-07-15

    Chagas' disease, caused by Trypanosoma cruzi, is endemic in 15 countries in Latin America. In this work a library of 38 coumarins was prepared in solution phase and evaluated against T. cruzi glycolytic enzyme glyceraldehyde-3-phosphate-dehydrogenase (gGAPDH). The synthetic route was based on the Knoevenagel condensation of different 2-hydroxybenzaldehydes with Meldrum's acid or diethyl malonate, followed by O-alkylation and/or transesterification reactions. Among the prepared coumarins, the best values obtained to inhibit 50% of the enzymatic activity range from 80 to 130 {mu}M. (author)

  3. Preparation and evaluation of a coumarin library towards the inhibitory activity of the enzyme gGAPDH from Trypanosoma cruzi

    International Nuclear Information System (INIS)

    Alvim Junior, Joel; Dias, Ricardo L.A.; Correa, Arlene G.; Castilho, Marcelo S.; Oliva, Glaucius

    2005-01-01

    Chagas' disease, caused by Trypanosoma cruzi, is endemic in 15 countries in Latin America. In this work a library of 38 coumarins was prepared in solution phase and evaluated against T. cruzi glycolytic enzyme glyceraldehyde-3-phosphate-dehydrogenase (gGAPDH). The synthetic route was based on the Knoevenagel condensation of different 2-hydroxybenzaldehydes with Meldrum's acid or diethyl malonate, followed by O-alkylation and/or transesterification reactions. Among the prepared coumarins, the best values obtained to inhibit 50% of the enzymatic activity range from 80 to 130 μM. (author)

  4. The influence of vitamin preparations on the activity of some enzymes of protein metabolism in the irradiated organism

    Energy Technology Data Exchange (ETDEWEB)

    Savitskij, I V; Savitskij, V I [Odesskij Meditsinskij Inst. (Ukrainian SSR)

    1975-01-01

    The effects of vitamin B/sub 6/; B/sub 6/ and ATP; B/sub 1/, B/sub 6/, FMN, PP, and ATP on the enzymatic activity of GOT, GPT, GDH, and OCT in liver cells of rabbits following whole-body irradiation with 450 R of X-rays were studied. Depending on the subcellular organization of the enzymes, on the time after irradiation and on the preparations administered changes of the enzymatic activity were found.

  5. Preparation of progenin III from total steroidal saponins of Dioscorea nipponica Makino using a crude enzyme from Aspergillus oryzae strain.

    Science.gov (United States)

    Liu, Tingqiang; Yu, Hongshan; Liu, Chunying; Bao, Yongming; Hu, Xiangchun; Wang, Yuanhao; Liu, Bing; Fu, Yaoyao; Tang, Sihui; Jin, Fengxie

    2013-05-01

    Progenin III, one of the most active spirostanol saponins, is a potential candidate for anti-cancer therapy due to its strong antitumor activity and low hemolytic activity. However, the concentration of progenin III is extremely low in natural Dioscorea plants. In this paper, the progenin III production from total steroidal saponins of Dioscorea nipponica Makino was studied using the crude enzyme from Aspergillus oryzae DLFCC-38. The crude enzyme converting total steroidal saponins into progenin III was obtained from the A. oryzae DLFCC-38 culture. For enzyme production, the strain was cultured for 72 h at 30 °C with shaking at 150 rpm in 5 % (w/v) malt extract medium containing 2 % (v/v) extract of D. nipponica as the enzyme inducer. The crude enzyme converted total steroidal saponins into major progenin III with a high yield when the reaction was carried out for 9 h at 50 °C and pH 5.0 with the 20 mg/ml of substrate. In the preparation of progenin III, 117 g of crude progenin III was obtained from 160 g of substrate, and the crude product was purified with silica gel column to obtain 60.3 g progenin III of 93.4 % purity.

  6. A food-grade process for isolation and partial purification of bacteriocins of lactic acid bacteria that uses diatomite calcium silicate.

    Science.gov (United States)

    Coventry, M J; Gordon, J B; Alexander, M; Hickey, M W; Wan, J

    1996-01-01

    Bacteriocins, including nisin, pediocin PO2, brevicin 286, and piscicolin 126, were extracted from fermentation media by adsorption onto Micro-Cel (a food-grade diatomite calcium silicate anticaking agent) and subsequent desorption. The optimal conditions for desorption of piscicolin 126 were determined and applied to other bacteriocins, and the relative purities of the desorbed preparations were compared. Piscicolin was not successfully desorbed from Micro-Cel at pH 1.0 to 12.0, with organic solvents, or by increase of ionic strength up to 1 M NaCl. However, 25 and 75% of the bacteriocin activity was desorbed by using 1% sodium deoxycholate and 1% sodium dodecyl sulfate (SDS), respectively. Higher levels (up to 100%) of desorption were achieved by repeated elution or by an increase in surfactant concentration. Desorption of piscicolin with 1/10 volume of SDS solution resulted in a preparation with 10 times concentration in activity, equivalent to that of ammonium sulfate preparations (409,600 to 819,200 activity units/ml). Determination of organic nitrogen (N) content revealed that the desorbed piscicolin preparations were substantially free of proteinaceous substances (approximately 92 to 99%) compared with original culture supernatants and ammonium sulfate preparations. Nisin, pediocin, and brevicin were also desorbed with 1% SDS with a similar level of purification. PMID:8633875

  7. Preparation of immobilized glucose oxidase wafer enzyme on calcium-bentonite modified by surfactant

    Science.gov (United States)

    Widi, R. K.; Trisulo, D. C.; Budhyantoro, A.; Chrisnasari, R.

    2017-07-01

    Wafer glucose oxidase (GOx) enzymes was produced by addition of PAH (Poly-Allyamine Hydrochloride) polymer into immobilized GOx enzyme on modified-Tetramethylammonium Hydroxide (TMAH) 5%-calsium-bentonite. The use of surfactant molecul (TMAH) is to modify the surface properties and pore size distribution of the Ca-bentonite. These properties are very important to ensure GOx molecules can be bound on the Ca-bentonit surface to be immobilized. The addition of the polymer (PAH) is expected to lead the substrates to be adsorbed onto the enzyme. In this study, wafer enzymes were made in various concentration ratio (Ca-bentonite : PAH) which are 1:0, 1:1, 1:2 and 1:3. The effect of PAH (Poly-Allyamine Hydrochloride) polymer added with various ratios of concentrations can be shown from the capacitance value on LCR meter and enzyme activity using DNS method. The addition of the polymer (PAH) showed effect on the activity of GOx, it can be shown from the decreasing of capacitance value by increasing of PAH concentration.

  8. Protoplast preparation from monokaryotic mycelium of Pleurotus sajor-caju using lysing enzyme

    International Nuclear Information System (INIS)

    Hassan Hamdani Mutaat; Mat Rasol Awang

    2004-01-01

    The objective of this study was to determine the optimum parameters of the factors influencing protoplast isolation from monokaryotic mycelium of Pleurotus sajor-caju using lysing enzyme from Trichoderma harzianurm. The study was conducted by manipulating the variables of the factors affecting protoplast isolation, such as age of mycelium culture, period for lysing of mycelium, concentration of lysing enzyme and concentration of osmotic stabilizer. The highest protoplast yield of 8.3 x 104 protoplast/ml was achieved when a 3-day P. sajor-caju mycelium, cultured statically, was incubated for 3 hours in a lytic mixture containing 7.5 mg/ml lysing enzyme and 1.2 M ammonium sulfate as osmotic stabilizer. This protoplast yield, however, is insufficient for regeneration and protoplast fusion works. (Author)

  9. Technique of ethanol food grade production with batch distillation and dehydration using starch-based adsorbent

    Science.gov (United States)

    Widjaja, Tri; Altway, Ali; Ni'mah, Hikmatun; Tedji, Namira; Rofiqah, Umi

    2015-12-01

    Development and innovation of ethanol food grade production are becoming the reasearch priority to increase economy growth. Moreover, the government of Indonesia has established regulation for increasing the renewable energy as primary energy. Sorghum is cerealia plant that contains 11-16% sugar that is optimum for fermentation process, it is potential to be cultivated, especially at barren area in Indonesia. The purpose of this experiment is to learn about the effect of microorganisms in fermentation process. Fermentation process was carried out batchwise in bioreactor and used 150g/L initial sugar concentration. Microorganisms used in this experiment are Zymomonas mobilis mutation (A3), Saccharomyces cerevisiae and mixed of Pichia stipitis. The yield of ethanol can be obtained from this experiment. For ethanol purification result, distillation process from fermentation process has been done to search the best operation condition for efficiency energy consumption. The experiment for purification was divided into two parts, which are distillation with structured packing steel wool and adsorption (dehydration) sequencely. In distillation part, parameters evaluation (HETP and pressure drop) of distillation column that can be used for scale up are needed. The experiment was operated at pressure of 1 atm. The distillation stage was carried out at 85 °C and reflux ratio of 0.92 with variety porosities of 20%, 40%, and 60%. Then the adsorption process was done at 120°C and two types of adsorbent, which are starch - based adsorbent with ingredient of cassava and molecular sieve 3A, were used. The adsorption process was then continued to purify the ethanol from impurities by using activated carbon. This research shows that the batch fermentation process with Zymomonas mobilis A3 obtain higher % yield of ethanol of 40,92%. In addition to that, for purification process, the best operation condition is by using 40% of porosity of stuctured packing steel wool in distillation

  10. Low-cost, easy-to-prepare magnetic chitosan microparticles for enzymes immobilization

    Czech Academy of Sciences Publication Activity Database

    Pospišková, K.; Šafařík, Ivo

    2013-01-01

    Roč. 96, č. 2 (2013), s. 545-548 ISSN 0144-8617 R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : Chitosan * Magnetite * Microwave irradiation * Enzymes immobilization Subject RIV: CE - Biochemistry Impact factor: 3.916, year: 2013

  11. Changes in activity of industrial enzyme preparations irradiated with sterilizing doses. Part of a coordinated programme on factors influencing the utilization of food irradiation process

    International Nuclear Information System (INIS)

    Bachman, S.

    1984-03-01

    Experiments were carried out to investigate the efficacy of irradiation to sterilize enzyme preparations. Irradiation doses up to 25 kGy caused no changes in basic organoleptic properties of commercial rennin preparations. Dose rate (from 0.5 to 13.5 kGy/hr) has no influence on the changes in enzyme activity during the storage period of 3 months. Doses ranging from 8 to 12 kGy are sufficient to sterilize commercial enzyme preparations. Non-purified, crude rennin preparations appear to be more resistant to radiation than purified samples. Rennin preparations purified by dialysis and treated with 25 kGy resulted in a reduction of activity of 20%. The activity of preparations purified by gel filtration was reduced to 50% when treated with the same dose

  12. Antioxidant activity of commercial food grade tannins exemplified in a wine model.

    Science.gov (United States)

    Ricci, Arianna; Olejar, Kenneth J; Parpinello, Giuseppina P; Mattioli, Alessia U; Teslić, Nemanja; Kilmartin, Paul A; Versari, Andrea

    2016-12-01

    Although commercial tannins are widely used in foods and beverages, an improved understanding of the structure and composition of vegetable tannins is needed to promote the exploitation of agri-food by-products and waste and their valorisation in more sustainable industrial applications. This study aims to characterise the phytochemical composition and antioxidant activity of 13 food grade tannins using multiple analytical approaches, including spectrophotometry and HPLC-ECD to determine the amount of targeted polyphenolic compounds. Moreover, the antioxidant activity of tannins was assessed in terms of radical scavenging activity (DPPH• assay), reducing power (FRAP assay), and redox properties (cyclic voltammetry, CV). A statistical univariate and multivariate correlation analysis was performed on 17 parameters including tannin content (range: 0.71-1.62 mM), gallic acid, (+)-catechin, syringic acid and (‒)-epicatechin. The compositional profile of tannins was related to their chemical moiety, antioxidant activity and the botanical origin of the extracts. In particular, the CV signal at 500 mV was highly correlated with DPPH• value due to the catechol ring of flavonoids and trigalloyl moieties of gallic acid-based compounds. Practical examples of tannins application in winemaking are discussed.

  13. A general method for selection of riboflavin-overproducing food grade micro-organisms

    Directory of Open Access Journals (Sweden)

    Rutten Ger

    2006-07-01

    Full Text Available Abstract Background This study describes a strategy to select and isolate spontaneous riboflavin-overproducing strains of Lactobacillus (Lb. plantarum, Leuconostoc (Lc. mesenteroides and Propionibacterium (P. freudenreichii. Results The toxic riboflavin analogue roseoflavin was used to isolate natural riboflavin-overproducing variants of the food grade micro-organisms Lb. plantarum, Lc. mesenteroides and P. freudenreichii strains. The method was successfully employed for strains of all three species. The mutation(s responsible for the observed overproduction of riboflavin were identified for isolates of two species. Conclusion Selection for spontaneous roseoflavin-resistant mutants was found to be a reliable method to obtain natural riboflavin-overproducing strains of a number of species commonly used in the food industry. This study presents a convenient method for deriving riboflavin-overproducing strains of bacterial starter cultures, which are currently used in the food industry, by a non-recombinant methodology. Use of such starter strains can be exploited to increase the vitamin content in certain food products.

  14. Solubilization of tea seed oil in a food-grade water-dilutable microemulsion.

    Directory of Open Access Journals (Sweden)

    Lingli Deng

    Full Text Available Food-grade microemulsions containing oleic acid, ethanol, Tween 20, and water were formulated as a carrier system for tea seed oil (Camellia oleifera Abel.. The effect of ethanol on the phase behavior of the microemulsion system was clearly reflected in pseudo-ternary diagrams. The solubilization capacity and solubilization efficiency of tea seed oil dispersions were measured along the dilution line at a 70/30 surfactant/oil mass ratio with Tween 20 as the surfactant and oleic acid and ethanol (1:3, w/w as the oil phase. The dispersed phase of the microemulsion (1.5% weight ratio of tea seed oil to the total amount of oil, surfactant, and tea seed oil could be fully diluted with water without phase separation. Differential scanning calorimetry and viscosity measurements indicated that both the carrier and solubilized systems underwent a similar microstructure transition upon dilution. The dispersion phases gradually inverted from the water-in-oil phase ( 45% water along the dilution line.

  15. Utilization of newly developed immobilized enzyme reactors for preparation and study of immunoglobulin G fragments

    Czech Academy of Sciences Publication Activity Database

    Korecká, L.; Bílková, Z.; Holčapek, M.; Královský, J.; Beneš, Milan J.; Lenfeld, Jiří; Minc, N.; Cecal, R.; Viovy, J.-L.; Przybylski, M.

    2004-01-01

    Roč. 808, č. 1 (2004), s. 15-24 ISSN 1570-0232. [International Symposium on Polymer Design for BioSeparation and Nanobiotechnology /8./. Compiegne, 27.11.2003-29.11.2003] Grant - others:GA ČR(CZ) GA203/02/0023 Program:GA Institutional research plan: CEZ:AV0Z4050913 Keywords : immobilized enzyme reactors * immunoglobulin G Subject RIV: CE - Biochemistry Impact factor: 2.176, year: 2004

  16. Polyphosphate present in DNA preparations from fungal species of Collectotrichum inhibits restriction endonucleases and other enzymes

    Science.gov (United States)

    Rodriguez, R.J.

    1993-01-01

    During the development of a procedure for the isolation of total genomic DNA from filamentous fungi (Rodriguez, R. J., and Yoder, 0. C., Exp. Mycol. 15, 232-242, 1991) a cell fraction was isolated which inhibited the digestion of DNA by restriction enzymes. After elimination of DNA, RNA, proteins, and lipids, the active compound was purified by gel filtration to yield a single fraction capable of complete inhibition of restriction enzyme activity. The inhibitor did not absorb uv light above 220 nm, and was resistant to alkali and acid at 25°C and to temperatures as high as 100°C. More extensive analyses demonstrated that the inhibitor was also capable of inhibiting T4 DNA ligase and TaqI DNA polymerase, but not DNase or RNase. Chemical analyses indicated that the inhibitor was devoid of carbohydrates, proteins, lipids, and nucleic acids but rich in phosphorus. A combination of nuclear magnetic resonance, metachromatic shift of toluidine blue, and gel filtration indicated that the inhibitor was a polyphosphate (polyP) containing approximately 60 phosphate molecules. The mechanism of inhibition appeared to involve complexing of polyP to the enzymatic proteins. All species of Colletotrichum analyzed produced polyP equivalent in chain length and concentration. A modification to the original DNA extraction procedure is described which eliminates polyP and reduces the time necessary to obtain DNA of sufficient purity for restriction enzyme digestion and TaqI polymerase amplification.

  17. l-Arabinose Isomerase and d-Xylose Isomerase from Lactobacillus reuteri: Characterization, Coexpression in the Food Grade Host Lactobacillus plantarum, and Application in the Conversion of d-Galactose and d-Glucose

    Science.gov (United States)

    2014-01-01

    The l-arabinose isomerase (l-AI) and the d-xylose isomerase (d-XI) encoding genes from Lactobacillus reuteri (DSMZ 17509) were cloned and overexpressed in Escherichia coli BL21 (DE3). The proteins were purified to homogeneity by one-step affinity chromatography and characterized biochemically. l-AI displayed maximum activity at 65 °C and pH 6.0, whereas d-XI showed maximum activity at 65 °C and pH 5.0. Both enzymes require divalent metal ions. The genes were also ligated into the inducible lactobacillal expression vectors pSIP409 and pSIP609, the latter containing a food grade auxotrophy marker instead of an antibiotic resistance marker, and the l-AI- and d-XI-encoding sequences/genes were coexpressed in the food grade host Lactobacillus plantarum. The recombinant enzymes were tested for applications in carbohydrate conversion reactions of industrial relevance. The purified l-AI converted d-galactose to d-tagatose with a maximum conversion rate of 35%, and the d-XI isomerized d-glucose to d-fructose with a maximum conversion rate of 48% at 60 °C. PMID:24443973

  18. Abalone Protein Hydrolysates: Preparation, Angiotensin I Converting Enzyme Inhibition and Cellular Antioxidant Activity.

    Science.gov (United States)

    Park, Soo Yeon; Je, Jae-Young; Hwang, Joung-Youl; Ahn, Chang-Bum

    2015-09-01

    Abalone protein was hydrolyzed by enzymatic hydrolysis and the optimal enzyme/substrate (E/S) ratios were determined. Abalone protein hydrolysates (APH) produced by Protamex at E/S ratio of 1:100 showed angiotensin I converting enzyme inhibitory activity with IC50 of 0.46 mg/mL, and APH obtained by Flavourzyme at E/S ratio of 1:100 possessed the oxygen radical absorbance capacity value of 457.6 μM trolox equivalent/mg sample. Flavourzyme abalone protein hydrolysates (FAPH) also exhibited H2O2 scavenging activity with IC50 of 0.48 mg/mL and Fe(2+) chelating activity with IC50 of 2.26 mg/mL as well as high reducing power. FAPH significantly (P<0.05) protected H2O2-induced hepatic cell damage in cultured hepatocytes, and the cell viability was restored to 90.27% in the presence of FAPH. FAPH exhibited 46.20% intracellular ROS scavenging activity and 57.89% lipid peroxidation inhibition activity in cultured hepatocytes. Overall, APH may be useful as an ingredient for functional foods.

  19. Development and characterization of food-grade tracers for the global grain tracing and recall system.

    Science.gov (United States)

    Lee, Kyung-Min; Armstrong, Paul R; Thomasson, J Alex; Sui, Ruixiu; Casada, Mark; Herrman, Timothy J

    2010-10-27

    Tracing grain from the farm to its final processing destination as it moves through multiple grain-handling systems, storage bins, and bulk carriers presents numerous challenges to existing record-keeping systems. This study examines the suitability of coded caplets to trace grain, in particular, to evaluate methodology to test tracers' ability to withstand the rigors of a commercial grain handling and storage systems as defined by physical properties using measurement technology commonly applied to assess grain hardness and end-use properties. Three types of tracers to dispense into bulk grains for tracing the grain back to its field of origin were developed using three food-grade substances [processed sugar, pregelatinized starch, and silicified microcrystalline cellulose (SMCC)] as a major component in formulations. Due to a different functionality of formulations, the manufacturing process conditions varied for each tracer type, resulting in unique variations in surface roughness, weight, dimensions, and physical and spectroscopic properties before and after coating. The applied two types of coating [pregelatinized starch and hydroxypropylmethylcellulose (HPMC)] using an aqueous coating system containing appropriate plasticizers showed uniform coverage and clear coating. Coating appeared to act as a barrier against moisture penetration, to protect against mechanical damage of the surface of the tracers, and to improve the mechanical strength of tracers. The results of analysis of variance (ANOVA) tests showed the type of tracer, coating material, conditioning time, and a theoretical weight gain significantly influenced the morphological and physical properties of tracers. Optimization of these factors needs to be pursued to produce desirable tracers with consistent quality and performance when they flow with bulk grains throughout the grain marketing channels.

  20. Use of the alr gene as a food-grade selection marker in lactic acid bacteria.

    Science.gov (United States)

    Bron, Peter A; Benchimol, Marcos G; Lambert, Jolanda; Palumbo, Emmanuelle; Deghorain, Marie; Delcour, Jean; De Vos, Willem M; Kleerebezem, Michiel; Hols, Pascal

    2002-11-01

    Both Lactococcus lactis and Lactobacillus plantarum contain a single alr gene, encoding an alanine racemase (EC 5.1.1.1), which catalyzes the interconversion of D-alanine and L-alanine. The alr genes of these lactic acid bacteria were investigated for their application as food-grade selection markers in a heterologous complementation approach. Since isogenic mutants of both species carrying an alr deletion (Deltaalr) showed auxotrophy for D-alanine, plasmids carrying a heterologous alr were constructed and could be selected, since they complemented D-alanine auxotrophy in the L. plantarum Deltaalr and L. lactis Deltaalr strains. Selection was found to be highly stringent, and plasmids were stably maintained over 200 generations of culturing. Moreover, the plasmids carrying the heterologous alr genes could be stably maintained in wild-type strains of L. plantarum and L. lactis by selection for resistance to D-cycloserine, a competitive inhibitor of Alr (600 and 200 micro g/ml, respectively). In addition, a plasmid carrying the L. plantarum alr gene under control of the regulated nisA promoter was constructed to demonstrate that D-cycloserine resistance of L. lactis is linearly correlated to the alr expression level. Finally, the L. lactis alr gene controlled by the nisA promoter, together with the nisin-regulatory genes nisRK, were integrated into the chromosome of L. plantarum Deltaalr. The resulting strain could grow in the absence of D-alanine only when expression of the alr gene was induced with nisin.

  1. Screening exogenous fibrolytic enzyme preparations for improved in vitro digestibility of bermudagrass haylage.

    Science.gov (United States)

    Romero, J J; Zarate, M A; Arriola, K G; Gonzalez, C F; Silva-Sanchez, C; Staples, C R; Adesogan, A T

    2015-04-01

    Our objectives were to evaluate the effects of 12 exogenous fibrolytic enzyme products (EFE) on ruminal in vitro neutral detergent fiber digestibility (NDFD) and preingestive hydrolysis of a 4-wk regrowth of bermudagrass haylage (BH), to examine the accuracy of predicting NDFD with EFE activity measures, and to examine the protein composition of the most and least effective EFE at increasing NDFD. In experiment 1, effects of 12 EFE on NDFD of BH were tested. Enzymes were applied in quadruplicate to culture tubes containing ground BH. The suspension was incubated for 24 h at 25 °C before addition of rumen fluid media and further incubation for 24 h at 39 °C. The experiment was repeated twice. In addition, regression relationships between EFE activity measures and NDFD were examined. Compared with the values for the control, 9 EFE-treated substrates had greater NDFD (37.8 to 40.4 vs. 35.6%), 6 had greater total VFA concentration (59.1 to 61.2 vs. 55.4 mM), and 4 had lower acetate-to-propionate ratios (3.03 to 3.16 vs. 3.24). In experiment 2, EFE effects on preingestive fiber hydrolysis were evaluated by incubating enzyme-treated and untreated bermudagrass suspensions in quadruplicate for 24 h at 25 °C and examining fiber hydrolysis measures. Compared with values for the control, 3 EFE reduced neutral detergent fiber concentration (62.8 to 63.7 vs. 67.3%), 10 increased release of water-soluble carbohydrates (26.8 to 58.5 vs. 22.8 mg/g), and 8 increased release of ferulic acid (210 to 391 vs. 198 μg/g). Regression analyses revealed that enzyme activities accurately [coefficient of determination (R(2)) = 0.98] predicted preingestive hydrolysis measures (water-soluble carbohydrates, ferulic acid), moderately (R(2) = 0.47) predicted neutral detergent fiber hydrolysis, but poorly (R(2) ≤ 0.1) predicted dry matter and NDFD. In experiment 3, proteomic tools were used to examine the protein composition of the most and least effective EFE at improving NDFD. Relative to

  2. A review of food-grade vectors in lactic acid bacteria: from the laboratory to their application.

    Science.gov (United States)

    Landete, José Maria

    2017-05-01

    Lactic acid bacteria (LAB) have a long history of use in fermented foods and as probiotics. Genetic manipulation of these microorganisms has great potential for new applications in food safety, as well as in the development of improved food products and in health. While genetic engineering of LAB could have a major positive impact on the food and pharmaceutical industries, progress could be prevented by legal issues related to the controversy surrounding this technology. The safe use of genetically modified LAB requires the development of food-grade cloning systems containing only the DNA from homologous hosts or generally considered as safe organisms, and not dependent antibiotic markers. The rationale for the development of cloning vectors derived from cryptic LAB plasmids is the need for new genetic engineering tools, therefore a vision from cryptic plasmids to applications in food-grade vectors for LAB plasmids is shown in this review. Replicative and integrative vectors for the construction of food-grade vectors, and the relationship between resistance mechanism and expression systems, will be treated in depth in this paper. Finally, we will discuss the limited use of these vectors, and the problems arising from their use.

  3. A potential food-grade cloning vector for Streptococcus thermophilus that uses cadmium resistance as the selectable marker.

    Science.gov (United States)

    Wong, Wing Yee; Su, Ping; Allison, Gwen E; Liu, Chun-Qiang; Dunn, Noel W

    2003-10-01

    A potential food-grade cloning vector, pND919, was constructed and transformed into S. thermophilus ST3-1, a plasmid-free strain. The vector contains DNAs from two different food-approved organisms, Streptococcus thermophilus and Lactococcus lactis. The 5.0-kb pND919 is a derivative of the cloning vector pND918 (9.3 kb) and was constructed by deletion of the 4.3-kb region of pND918 which contained DNA from non-food-approved organisms. pND919 carries a heterologous native cadmium resistance selectable marker from L. lactis M71 and expresses the Cd(r) phenotype in S. thermophilus transformants. With the S. thermophilus replicon derived from the shuttle vector pND913, pND919 is able to replicate in the two S. thermophilus industrial strains tested, ST3-1 and ST4-1. Its relatively high retention rate in S. thermophilus further indicates its usefulness as a potential food-grade cloning vector. To our knowledge, this is the first report of a replicative potential food-grade vector for the industrially important organism S. thermophilus.

  4. Using Food Grade Lye “omushelekha” in the Formulation of Health Products from Commonly Consumed African Indigenous Vegetables and Vegetable Combinations

    Directory of Open Access Journals (Sweden)

    Florence O Habwe

    2011-05-01

    Full Text Available Background: Lye, sodium hydroxide and potassium hydroxide has been used over the years in food preparation including the preparation of vegetables and dried meat products, washing or chemical peeling of fruits and vegetables, cocoa processing, caramel production, poultry scalding and cooking among others. Lye is believed to improve the organoleptic properties and also enhances the nutritional value to the products.Objective: To assess the effect of food grade lye on the levels of copper and iron in the raw, boiled and boiled-fried single vegetables and vegetable combinations treated with and without food grade lye.Methods: Single vegetables, Crotalaria occroleuca, Solanum scabrum, Vigna unguiculata and Amaranthus blitum and their combinations were cooled and kept in the fridge at 4oCs. Elemental analysis was done for the raw, boiled and boiled-fried samples using Atomic Absorption Spectrophotometry (AAS under standard conditions using wavelengths of 248.3nm for iron and 324.2nm for copper. Paired t-test was used to compare the iron and copper levels of the boiled and boiled-fried vegetables while the independent t-test was done to assess the levels of iron and copper in the raw, boiled and boiled fried samples.Results: Boiled-fried samples recorded higher content of iron and copper than the boiled ones. A combination of Amaranthus blitum-Crotolaria occloreuca boiled without lye boiled-fried with lye, and boiled-fried without lye had the highest copper contents of 1.66mg/100gram, 4.56mg/100gram, and 4.56mg/100gram respectively, compared to Amaranthus blitum aloneFunctional Foods in Heals and Disease 2011; 5:189-197(3.48mg/100gram and Crotolaria occloreuca (0.42mg/100gram. A combination of Amaranthus blitum-Crotolaria occloreuca boiled in non-lye water, and those boiled-fried with and without lye had the highest extractable iron of 557mg/100g, 859.2mg/100g, and 859.2mg/100g respectively. Iron content was high in the Solanum scabrum (281.1mg/100g

  5. Preparation of reusable bioreactors using reversible immobilization of enzyme on monolithic porous polymer support with attached gold nanoparticles.

    Science.gov (United States)

    Lv, Yongqin; Lin, Zhixing; Tan, Tianwei; Svec, Frantisek

    2014-01-01

    Porcine lipase has been reversibly immobilized on a monolithic polymer support containing thiol functionalities prepared within confines of a fused silica capillary and functionalized with gold nanoparticles. Use of gold nanoparticles enabled rejuvenation of the activity of the deactivated reactor simply by stripping the inactive enzyme from the nanoparticles using 2-mercaptoethanol and subsequent immobilization of fresh lipase. This flow through enzymatic reactor was then used to catalyze the hydrolysis of glyceryl tributyrate (tributyrin). The highest activity was found within a temperature range of 37-40°C. The reaction kinetics is characterized by Michaelis-Menten constant, Km  = 10.9 mmol/L, and maximum reaction rate, Vmax  = 5.0 mmol/L min. The maximum reaction rate for the immobilized enzyme is 1,000 times faster compared to lipase in solution. The fast reaction rate enabled to achieve 86.7% conversion of tributyrin in mere 2.5 min and an almost complete conversion in 10 min. The reactor lost only less than 10% of its activity even after continuous pumping through it a solution of substrate equaling 1,760 reactor volumes. Finally, potential application of this enzymatic reactor was demonstrated with the transesterification of triacylglycerides from kitchen oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. © 2013 Wiley Periodicals, Inc.

  6. The influence of Saccharomyces cerevisiae enzyme ratio on preparation virgin coconut oil for candidate in-house reference materials

    Science.gov (United States)

    Rohyami, Yuli; Anjani, Rafika Debby; Purwanti, Napthalina Putri

    2017-03-01

    Virgin coconut oil is an excellent product which has result of oil processing business opportunities in the international market. Standardization of virgin coconut oil necessary to satisfy the requirements industry needs. This research is expected as procedure preparation of reference materials. Preparation of virgin coconut oil by Sacharomycescerevisiaeenzyme. Based on the results of this study concluded that the ratio of Saccharomyces cerevisiae can affect the yield of virgin coconut oil produced. The preparation of virgin coconut oil enzymatically using a variety of mass ratio of 0.001 to 0.006% is obtained yield average of 12.40%. The optimum separation of virgin coconut oil on the use of enzymes with a mass ratio of 0.002%. The average water content at a ratio of 0.002% is 0.04 % with a value of uncertainty is 0.005%. The average iodine number in virgin coconut oil produced is 2.4403 ± 0,1974 grams of iodine per 100 grams of oil and optimum iodine number is obtained from the manufacturing process virgin coconut oil with a ratio of 0.006% Saccharomyces cerevisiae. Sacharomycescerevisiae with a ratio of 0.002% results virgin coconut oil with acid number 0.3068 ± 0.1098%. The peroxide value of virgin coconut oil between 0.0108 ± 0.009 to 0.0114 ± 0015milli-equivalent per kilograms. Organoleptic test results and test chemical parameters can be used as the test data that can be developed in prototype preparation of candidate in-house reference material in the testing standards of quality virgin coconut oil.

  7. Improving the performance of dairy cattle with a xylanase-rich exogenous enzyme preparation.

    Science.gov (United States)

    Romero, J J; Macias, E G; Ma, Z X; Martins, R M; Staples, C R; Beauchemin, K A; Adesogan, A T

    2016-05-01

    The objective of this experiment was to examine effects of adding 2 exogenous fibrolytic enzymes (EFE) to the total mixed ration (TMR) on the performance of lactating dairy cows (experiment 1) and the kinetics of ruminal degradation of the diet (experiment 2). Twelve EFE had been screened in a series of in vitro assays that identified the most potent EFE and their optimal doses for increasing the digestibility of bermudagrass. In experiment 1, 66 Holstein cows (21±5 d in milk) were grouped by previous milk production and parity (45 multiparous and 21 primiparous) and assigned randomly to 1 of the following 3 treatments: (1) control (CON, untreated), (2) Xylanase Plus [2A, 1mL/kg of TMR dry matter (DM); Dyadic International, Jupiter, FL], and (3) a 75:25 (vol/vol) mixture of Cellulase Plus and Xylanase Plus EFE (3A, 3.4mL/kg of TMR DM; Dyadic International). The EFE were sprayed twice daily onto a TMR (10% bermudagrass silage, 35% corn silage, 5% alfalfa-orchardgrass hay mixture, and 50% concentrates; DM basis) and fed for a 14-d training and covariate period and a 70-d measurement period. Experiment 2 aimed to examine the in situ DM ruminal degradability and ruminal fermentation measurements of the diets fed in experiment 1. Three ruminally fistulated lactating Holstein cows were assigned to the diets. The experiment had a 3×3 Latin square design with 23-d periods. In experiment 1, application of 2A increased intakes (kg/d) of DM (23.5 vs. 22.6), organic matter (21.9 vs. 20.9), and crude protein (3.9 vs. 3.7) and tended to increase yields (kg/d) of fat-corrected milk (41.8 vs. 40.7) and milk fat (1.48 vs. 1.44). In particular, 2A increased milk yield (kg/d) during wk 3 (41.2 vs. 39.8, tendency), 6 (41.9 vs. 40.1), and 7 (42.1 vs. 40.4), whereas 3A increased milk yield (kg/d) during wk 6 (41.5 vs. 40.1, tendency), 8 (41.8 vs. 40.0), and 9 (40.9 vs. 39.5, tendency). In experiment 2, EFE treatment did not affect ruminal DM degradation kinetics or ruminal pH, ammonia

  8. A Potential Food-Grade Cloning Vector for Streptococcus thermophilus That Uses Cadmium Resistance as the Selectable Marker

    OpenAIRE

    Wong, Wing Yee; Su, Ping; Allison, Gwen E.; Liu, Chun-Qiang; Dunn, Noel W.

    2003-01-01

    A potential food-grade cloning vector, pND919, was constructed and transformed into S. thermophilus ST3-1, a plasmid-free strain. The vector contains DNAs from two different food-approved organisms, Streptococcus thermophilus and Lactococcus lactis. The 5.0-kb pND919 is a derivative of the cloning vector pND918 (9.3 kb) and was constructed by deletion of the 4.3-kb region of pND918 which contained DNA from non-food-approved organisms. pND919 carries a heterologous native cadmium resistance se...

  9. Development of technology for gourmet smoked products from cod species using enzyme preparation from hepatopancreas of snow crab Chionoecetes opilio

    Directory of Open Access Journals (Sweden)

    E. B. Shkuratova

    2017-01-01

    Full Text Available At the Food Production Department of Murmansk State Technical University (MSTU was developed a technology of production of smoked fish products with the use of air-flue mixture, produced in an infrared smoke generator under conditions of low-temperature pyrolysis of wood chips with an initial moisture content of 40 to 60% and a bulk density of from 104 to 154 kg/m3. A method of producing smoke and its hardware design enabled to securely control the temperature of the smoke receiving smoking environment, which guarantees a minimum content of threat to human health of polycyclic aromatic hydrocarbons (РАНs. The developed technology involves short cycle smoked salted semi – fish fillets and allows to obtain finished products with excellent organoleptic properties. The content of РАНs in finished products less than 0.0002 microgram/kg, which is significantly below the maximum permissible concentrations (MPC according to the requirements of SаnРiN 2.3.2.1078 (less than 0.001 mg/kg product and according to the requirements of TR CU 021/2011 (0.005 mg/kg product. This technology successfully implemented in production at fish processing plants in Murmansk region. However, marketing research has shown that the market for smoked fish in the Murmansk region is characterized by a narrow range, which affects consumer demand and reduces the competitiveness of the regional enterprises-manufacturers of smoked products. To solve this problem it is offered to expand the range of smoked fish products due to use of non-traditional Smoking techniques raw materials – fillet of cod fish (saithe, haddock, cod. To improve consumer properties of products, in particular, to improve the indicator of “consistency: and "juiciness" of the proposed use on the stage of the salting of prefabricated enzyme preparation from hepatopancreas of snow crab (Chionoecetes opilio, added to brine with density of 1.18 to 1.2 g/сm3 at a dosage of 0.04%, the curing time of

  10. Studies on the preparation of immobilized enzymes by radio-polymerization, 10. Preparation of. beta. -galactosidase and its utilization for the continuous determination of lactose. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Amarakone, S P [Ceylon Inst. of Scientific and Industrial Research, Colombo (Sri Lanka); Hayashi, Toru; Kawashima, Koji

    1983-03-01

    ..beta..-Galactosidase of E. coli origin was immobilized in the form of beads by the radiopolymerization of different combinations of monomers using a gamma irradiation technique. With the dialysed enzyme, recoveries of over 300 % could be obtained on suitable monomer combinations containing magnesium and sodium acrylates. The recovery of the enzyme also depended on the irradiation time. The immobilized enzyme had better pH and temperature stability and was less affected by the presence of metal ions in the medium, compared to the native enzyme. The optimum pH and temperatures of the immobilized enzyme were different from those of the native enzyme and were 7.0 to 7.5 and 50 deg C respectively. The immobilized enzyme was used in a column for the continuous determination of lactose with a standard type autoanalyser. Good linearity could be observed even up to 3% lactose in the sample.

  11. Suitability of Different Food Grade Materials for the Encapsulation of Some Functional Foods Well Reported for Their Advantages and Susceptibility.

    Science.gov (United States)

    Wani, Touseef Ahmed; Shah, Adil Gani; Wani, Sajad Mohd; Wani, Idrees Ahmed; Masoodi, Farooq Ahmad; Nissar, Nazia; Shagoo, Mudasir Ahmad

    2016-11-17

    Functional foods find a very important place in the modern era, where different types of cancer, diabetes, cardiovascular diseases, etc. are on a high. Irrespective of the abundance of bioactive components in different fruits and vegetables, their low solubility in aqueous solution, vulnerability to destruction in different environmental and gastrointestinal conditions and a low intestinal absorption becomes a concern. Because it is quite difficult to commercialize non food materials for the food encapsulation purposes due to their safety concerns in the human body, scientists in the recent times have come up with the idea of encapsulating the different bioactive components in different food grade materials that are able to safeguard these bioactive components against the different environmental and gastrointestinal conditions and ensure their safe and targeted delivery at their absorption sites. Different food grade encapsulation materials including various oligosaccharides, polysaccharides (starch, cyclodextrins, alginates, chitosan, gum arabic, and carboxymethyl cellulose) and proteins and their suitability for encapsulating various bioactive components like flavonoids (catechins, rutin, curcumin, hesperetin, and vanillin), nonflavonoids (resveratrol), carotenoids (β-carotene, lycopene, and lutein), and fatty acids (fish oil, flaxseed oil, and olive oil) of high medical and nutritional value are reviewed here.

  12. Food Grade Grease Berbahan Baku Minyak Sawit Crude Palm Oil (Cpo Off Grade Dengan Variasi Konsentrasi Thickening

    Directory of Open Access Journals (Sweden)

    Martanto Totok

    2017-03-01

    Full Text Available Food grade grease (FGG is a kind of lubricant made from vegetable oil. Food Grease isconsidered safe for healthy and it does not pollute the environment so that it can be veryimportant for particular industries such as pharmaceutical, animal feeding, cosmetic, andespecially food industry. This study is aiming at obtaining optimum basic formulation ofthickening agent (LiOH that can produce qualified food grade grease. It is a kind of factorialexperimental study by using complete random sampling. Based on Fisher test, the treatmentshows a different result significantly. Then, it is continued by conducting Duncan’s MultipleRange Test (DMRT. 2% of activated charcoal is the best treatment because it results FFAscore, lower water content, and the bright yellow color that is shown by the score of 5.48%,0.0498 %, and 3 % that successively obtained. The treatment on thickening agent (LiOH(P1 and the revious one (L1 are the best treatment which produce qualified food gradegrease, corrosion resistance value 12.0, dropping point 130C, lubricating texture value 1,pH value 9.45, water content 0.19%, and ash content value 0.76%.

  13. Construction of a food-grade cloning vector for Lactobacillus plantarum and its utilization in a food model.

    Science.gov (United States)

    Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

    2012-01-01

    The development of Lactobacillus plantarum to be used in starter cultures in the food industry has been limited because of the lack of a food-grade cloning vector for the bacterium. In this study, the plasmid pFLP1 was constructed by joining 2 DNA fragments derived from food-approved organisms. The 5.2-kb BamHI/KpnI DNA fragment of pRV566 containing the theta-type replicon of Lactobacillus sakei was ligated to the BamHI/KpnI DNA fragment of a 2.9-kb lactococcal cadmium resistance determinant amplified from pND918. The 8.1-kb newly constructed plasmid could transform L. plantarum N014, a bacteriocin-producing bacteria originally isolated from nham, a traditional Thai fermented sausage. The resulting transformant, L. plantarum N014-FLP, and its parent strain were shown to be very similar in growth rate and bacteriocin activity. In addition, the plasmid was very stable in its host bacteria under nonselective pressure for 100 generations in MRS medium and for 5 days in a nham model. These results suggest that pFLP1 is a potential food-grade cloning vector for L. plantarum.

  14. The use of food grade oil in the prevention of vase tunicate fouling on mussel aquaculture gear

    Directory of Open Access Journals (Sweden)

    Jiselle A. BAKKER

    2011-01-01

    Full Text Available Current mitigation strategies against invasive tunicates on mussel aquaculture gear in Prince Edward Island concentrate on labour-intensive and costly fouling removal. Instead of removal, this study focused on preventing the settlement of the vase tunicate Ciona intestinalis and other fouling organisms by applying a layer of food grade oil to gear prior to recruitment. Laboratory tests established the adherence and persistence of shortening, a food grade oil with a melting point exceeding ambient water temperatures, to rope and mussels. In situ tests showed that shortening decreased C. intestinalis weight and abundance on buoys, spat collector ropes and collector plates but not on mussel socks. Fouling by algae and other tunicates was significantly reduced on most substrates. There were no detrimental effects of shortening treatment on mussel length and abundance on mussel socks, but total mussel weight was significantly lower on shortening-treated socks. Shortening treatment did not significantly affect mussel spat settlement on spat collector ropes, but further evaluation is required. Overall, shortening application has considerable potential for reducing tunicate and other fouling, particularly on buoys.

  15. Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays

    Science.gov (United States)

    Reinecke, D. M.; Bandurski, R. S.

    1988-01-01

    Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

  16. Effect of Enzyme Preparation with Activity Directed Towards Degradation of Non Starch Polysaccharides on Yellow Lupine Seed Based Diet for Young Broilers

    Directory of Open Access Journals (Sweden)

    Bogusław I Olkowski

    2010-01-01

    Full Text Available This work examined the impact of enzyme preparation with specific activity towards non starch polysaccharides on performance, morphological characteristics of gastrointestinal tract organs, microscopic evaluation of jejunal mucosa, and microbial status of ileum, caeca, and excreta in broilers fed a diet containing a high content of lupine meal. One-day-old chickens (Ross 308, mixed sex were randomly divided into control and experimental groups. Each group consisted of 36 birds, with 6 replications,and with 6 chickens per replication. The control group was fed the basal diet (consisting of maize and 40% of lupine, while the experimental treatment group was fed the basal diet supplemented with 0.06% commercial enzyme (Ronozyme VP. Chickens were fed diets in mash form for 4 weeks. Enzyme preparation significantly (P P P Enterobacteriaceae in caeca and excreta, and coliforms in excreta only (P < 0.01. Appropriate combination of enzyme preparations with activity towards degrading carbohydrates may offer a potential to reduce the deleterious impact of lupine in broilers.

  17. The effects of certain enzymes on the rheology of dough and the quality characteristics of bread prepared from wheat meal.

    Science.gov (United States)

    Altınel, Burak; Ünal, S Sezgin

    2017-05-01

    This study was carried out to evaluate the effects of amyloglucosidase, glucose oxidase, hemicellulase (mainly consist of endo-1,4-β-xylanase), cellulase, lipase, and the combination of phospholipase and hemicellulase (phospholipase + hemicellulase) on the extensographic properties of dough and the quality characteristics of bread prepared from wheat meal. The enzymes were added separately in two different amounts. The addition of glucose oxidase (at 0.0003-0.001%) caused a significant decrease in the resistance to extension, ratio of resistance to extensibility and energy values of the wheat meal dough compared with the control dough. The addition of hemicellulase (at 0.001-0.005%) and phospholipase + hemicellulase (at 0.0006-0.0009%) also improved the wheat meal dough rheology by reducing the resistance to extension and the ratio of resistance to extensibility. Glucose oxidase (at 0.0003-0.001%), hemicellulase (at 0.001-0.005%) and phospholipase + hemicellulase (at 0.0006-0.0009%) addition improved the specific volume of wheat meal bread compared with the control bread. Increasing the dosage of glucose oxidase from 0.0003 to 0.001% caused a further increase in the specific volume of wheat meal bread. The addition of hemicellulase (at 0.001-0.005%) caused a significant decrease in the baking loss and an increase in the moisture content of wheat meal bread compared with the control bread. The addition of amyloglucosidase (at 0.000875-0.001%), lipase (at 0.0002-0.001%) and cellulase (at 0.0003-0.0005%) did not considerably affected the dough rheological and the quality characteristics of wheat meal bread.

  18. Immobilisation of enzymes on poly(aniline)-poly(anion) composite films. Preparation of bioanodes for biofuel cell applications.

    Science.gov (United States)

    Simon, Evelyne; Halliwell, Catherine M; Toh, Chee Seng; Cass, Anthony E G; Bartlett, Philip N

    2002-01-01

    Immobilisation of enzymes is important for applications such as biosensors or biofuel cells. A poly(histidine) tag had been introduced on the C terminus of a lactate dehydrogenase enzyme. This mutant enzyme was then immobilised onto poly(aniline) (PANi)-poly(anion) composite films, PANi-poly(vinylsulfonate) (PVS) or PANi-poly(acrylate) (PAA). The NADH produced by the immobilised enzyme in the presence of beta-nicotinamide adenine dinucleotide (NAD(+)) and lactate is oxidised at the poly(aniline)-coated electrode at 0.05 to 0.1 V vs. saturated calomel electrode (SCE) at 35 degrees C.

  19. Enzyme Informatics

    Science.gov (United States)

    Alderson, Rosanna G.; Ferrari, Luna De; Mavridis, Lazaros; McDonagh, James L.; Mitchell, John B. O.; Nath, Neetika

    2012-01-01

    Over the last 50 years, sequencing, structural biology and bioinformatics have completely revolutionised biomolecular science, with millions of sequences and tens of thousands of three dimensional structures becoming available. The bioinformatics of enzymes is well served by, mostly free, online databases. BRENDA describes the chemistry, substrate specificity, kinetics, preparation and biological sources of enzymes, while KEGG is valuable for understanding enzymes and metabolic pathways. EzCatDB, SFLD and MACiE are key repositories for data on the chemical mechanisms by which enzymes operate. At the current rate of genome sequencing and manual annotation, human curation will never finish the functional annotation of the ever-expanding list of known enzymes. Hence there is an increasing need for automated annotation, though it is not yet widespread for enzyme data. In contrast, functional ontologies such as the Gene Ontology already profit from automation. Despite our growing understanding of enzyme structure and dynamics, we are only beginning to be able to design novel enzymes. One can now begin to trace the functional evolution of enzymes using phylogenetics. The ability of enzymes to perform secondary functions, albeit relatively inefficiently, gives clues as to how enzyme function evolves. Substrate promiscuity in enzymes is one example of imperfect specificity in protein-ligand interactions. Similarly, most drugs bind to more than one protein target. This may sometimes result in helpful polypharmacology as a drug modulates plural targets, but also often leads to adverse side-effects. Many cheminformatics approaches can be used to model the interactions between druglike molecules and proteins in silico. We can even use quantum chemical techniques like DFT and QM/MM to compute the structural and energetic course of enzyme catalysed chemical reaction mechanisms, including a full description of bond making and breaking. PMID:23116471

  20. Preparation of catalytically active, covalent α-polylysine-enzyme conjugates via UV/vis-quantifiable bis-aryl hydrazone bond formation.

    Science.gov (United States)

    Grotzky, Andrea; Manaka, Yuichi; Kojima, Taisuke; Walde, Peter

    2011-01-10

    Covalent UV/vis-quantifiable bis-aryl hydrazone bond formation was investigated for the preparation of conjugates between α-poly-d-lysine (PDL) and either α-chymotrypsin (α-CT) or horseradish peroxidase (HRP). PDL and the enzymes were first modified via free amino groups with the linking reagents succinimidyl 6-hydrazinonicotinate acetone hydrazone (S-HyNic, at pH 7.6) and succinimidyl 4-formylbenzoate (S-4FB, at pH 7.2), respectively. The modified PDL and enzymes were then conjugated at pH 4.7, whereby polymer chains carrying several enzymes were obtained. Kinetics of the bis-aryl hydrazone bond formation was investigated spectrophotometrically at 354 nm. Retention of the enzymatic activity after conjugate formation was confirmed by using the substrates N-succinimidyl-l-Ala-l-Ala-l-Pro-l-Phe-p-nitroanilide (for α-CT) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS, for HRP). Thus, not only a mild and efficient preparation and convenient quantification of a conjugate between the polycationic α-polylysine and enzymes could be shown, but also the complete preservation of the enzymatic activity.

  1. In vitro uptake and immune functionality of digested Rosemary extract delivered through food grade vehicles.

    Science.gov (United States)

    Arranz, E; Guri, A; Fornari, T; Mendiola, J A; Reglero, G; Corredig, M

    2017-07-01

    The digestion, absorption, uptake and bioavailability of a rosemary supercritical fluid extract encapsulated in oil in water emulsion were studied. Two emulsions with opposite surface charge were prepared, containing 7% canola oil, and either 2% lactoferrin or whey protein isolate. When absorption and uptake of carnosic acid and carnosol were followed on Caco-2 cell monolayers, there were no differences with protein type. However, when co-cultures of HT-29 MTX were employed, the presence of mucus caused a higher retention of carnosic acid in the apical layer for lactoferrin emulsions. The immune activity of the bioavailable fractions collected from cell absorption experiments was tested ex vivo on murine splenocytes. Although transport through the intestinal barrier models was low, the bioavailable fractions showed a significant effect on splenocytes proliferation. These results demonstrated the potential of using rosemary supercritical extract through protein stabilized oil in water emulsions, as a food with immunomodulatory functionality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Food-grade protein-based nanoparticles and microparticles for bioactive delivery: fabrication, characterization, and utilization.

    Science.gov (United States)

    Davidov-Pardo, Gabriel; Joye, Iris J; McClements, David Julian

    2015-01-01

    Proteins can be used to fabricate nanoparticles and microparticles suitable for use as delivery systems for bioactive compounds in pharmaceutical, food, cosmetic, and other products. Food proteins originate from various animal or vegetal sources and exhibit a wide diversity of molecular and physicochemical characteristics, e.g., molecular weight, conformation, flexibility, polarity, charge, isoelectric point, solubility, and interactions. As a result, protein particles can be assembled using numerous different preparation methods, from one or more types of protein or from a combination of a protein and another type of biopolymer (usually a polysaccharide). The final characteristics of the particles produced are determined by the proteins and/or polysaccharides used, as well as the fabrication techniques employed. This chapter provides an overview of the functional properties of food proteins that can be used to assemble nanoparticles and microparticles, the fabrication techniques available to create those particles, the factors that influence their stability, and their potential applications within the food industry. © 2015 Elsevier Inc. All rights reserved.

  3. Microstructure characterization of a food-grade U-type microemulsion system by differential scanning calorimetry and electrical conductivity techniques.

    Science.gov (United States)

    Zhang, Hui; Taxipalati, Maierhaba; Que, Fei; Feng, Fengqin

    2013-12-01

    The microstructure transitions of a food-grade U-type microemulsion system containing glycerol monolaurate and propionic acid at a 1:1 mass ratio as oil phase and Tween 80 as surfactant were investigated along a water dilution line at a ratio of 80:20 mass% surfactant/oil phase, based on a previously studied phase diagram. From the water thermal behaviours detected by differential scanning calorimetry, three structural regions are identified along the dilution line. In the first region, all water molecules are confined to the water core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, transforms into bicontinuous in the second region, and finally the microemulsion become o/w in the third region. The thermal transition points coincide with the structural phase transitions by electrical conductivity measurements, indicating that the structural transitions occur at 35 and 65 mass% of water along the dilution line. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Production of the natural iron chelator deferriferrichrysin from Aspergillus oryzae and evaluation as a novel food-grade antioxidant.

    Science.gov (United States)

    Todokoro, Takehiko; Fukuda, Katsuharu; Matsumura, Kengo; Irie, Motoko; Hata, Yoji

    2016-07-01

    Deferriferrichrysin (Dfcy) is a siderophore found in foods fermented by Aspergillus oryzae and is a promising candidate for an antioxidant food additive because of its high binding constant toward iron. However, the Dfcy concentration is typically low in foods and cultures. We optimised culture conditions to improve Dfcy production to 2800 mg L(-1) from 22.5 mg L(-1) under typical conditions. Then, we evaluated the potential of Dfcy as a food additive by measuring its safety, stability, and antioxidant activity. Dfcy was sufficiently stable that over 90% remained after pasteurisation at 63 °C for 30 min at pH 3-11, or after sterilisation at 120 °C for 4 min at pH 4-6. Dfcy showed high antioxidant activity in an oil-in-water model, where inhibition of lipid oxidation was measured by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) assays. Dfcy decreased PV and TBARS by 83% and 75%, respectively. Antioxidant activity of Dfcy was equal to or higher than that of the synthetic chelator EDTA. Our study provides the first practical method for production of Dfcy. Dfcy can be a novel food-grade antioxidant and the first natural alternative to the synthesised iron chelator EDTA. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  5. Migration of nonylphenol from food-grade plastic is toxic to the coral reef fish species Pseudochromis fridmani.

    Science.gov (United States)

    Hamlin, Heather J; Marciano, Kathleen; Downs, Craig A

    2015-11-01

    Nonylphenol (NP) is a non-ionic surfactant used extensively in industrial applications, personal care products, and many plastics. We exposed marine orchid dottybacks (Pseudochromis fridmani) for 48h to either glass, Teflon, or two bags labeled as FDA food-grade polyethylene (PE1 and PE2) from different manufacturers. The PE2 bags leached high levels of NP into the contact water, which were taken up by the fish, and decreased short and long-term survival. Concentrations of NP that leached from the bags were consistent with 96h LC50 values determined in this study, indicating NP is the likely toxic agent. Despite being similarly labeled, the NP concentrations that leached from the bags and the resultant toxicity to the fish varied dramatically between manufacturers. This study highlights that some plastics, labeled as food-safe, can be highly toxic to aquatic animals, and could pose a greater threat to humans than previously realized. This study also highlights risks for aquatic animals exposed to increasing quantities of plastic waste. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Production of Ethanol and Biomass from Thin Stillage Using Food-Grade Zygomycetes and Ascomycetes Filamentous Fungi

    Directory of Open Access Journals (Sweden)

    Jorge A. Ferreira

    2014-06-01

    Full Text Available A starch-based ethanol facility producing 200,000 m3 ethanol/year also produces ca. 2 million m3 thin stillage, which can be used to improve the entire process. In this work, five food-grade filamentous fungi, including a Zygomycete and four Ascomycetes were successfully grown in thin stillage containing 9% solids. Cultivation with Neurospora intermedia led to the production of ca. 16 g·L−1 biomass containing 56% (w/w crude protein, a reduction of 34% of the total solids, and 5 g·L−1 additional ethanol. In an industrial ethanol production process (200,000 m3 ethanol/year, this can potentially lead to the production of 11,000 m3 extra ethanol per year. Cultivation with Aspergillus oryzae resulted in 19 g·L−1 biomass containing 48% (w/w crude protein and the highest reduction of the thin stillage glycerol (54% among the Ascomycetes. Cultivation with Rhizopus sp. produced up to 15 g·L−1 biomass containing 55% (w/w crude protein. The spent thin stillage had been reduced up to 85%, 68% and 21% regarding lactic acid, glycerol and total solids, respectively. Therefore, N. intermedia, in particular, has a high potential to improve the ethanol process via production of additional ethanol and high-quality biomass, which can be considered for animal feed applications such as for fish feed.

  7. A bioengineered nisin derivative, M21A, in combination with food grade additives eradicates biofilms of Listeria monocytogenes.

    Directory of Open Access Journals (Sweden)

    Lorraine Anne Draper

    2016-11-01

    Full Text Available The burden of foodborne disease has large economic and social consequences worldwide. Despite strict regulations, a number of pathogens persist within the food environment, which is greatly contributed to by a build-up of resistance mechanisms and also through the formation of biofilms. Biofilms have been shown to be highly resistant to a number of antimicrobials and can be extremely difficult to remove once they are established. In parallel, the growing concern of consumers regarding the use of chemically derived antimicrobials within food has led to a drive towards more natural products. As a consequence, the use of naturally derived antimicrobials has become of particular interest. In this study we investigated the efficacy of nisin A and its bioengineered derivative M21A in combination with food grade additives to treat biofilms of a representative strain of Listeria monocytogenes. Investigations revealed the enhanced antimicrobial effects, in liquid culture, of M21A in combination with citric acid or cinnamaldehyde over its wild type nisin A counterpart. Subsequently, an investigation was conducted into the effects of these combinations on an established biofilm of the same strain. Nisin M21A (0.1 µg/ml alone or in combination with cinnamaldehyde (35 µg/ml or citric acid (175 µg/ml performed significantly better than combinations involving nisin A. All combinations of M21A with either citric acid or cinnamaldehyde eradicated the L. monocytogenes biofilm (in relation to a non-biofilm control. We conclude that M21A in combination with available food additives could further enhance the antimicrobial treatment of biofilms within the food industry, simply by substituting nisin A with M21A in current commercial products such as Nisaplin (Danisco, DuPont.

  8. Vasomotor function in rat arteries after ex vivo and intragastric exposure to food-grade titanium dioxide and vegetable carbon particles

    DEFF Research Database (Denmark)

    Jensen, Ditte Marie; Christophersen, Daniel Vest; Sheykhzade, Majid

    2018-01-01

    -grade particle exposure on vasomotor function and systemic oxidative stress in an ex vivo study and intragastrically exposed rats.Methods: In an ex vivo study, aorta rings from naive Sprague-Dawley rats were exposed for 30 min to food-grade TiO2 (E171), benchmark TiO2 (Aeroxide P25), food-grade vegetable carbon...... (E153) or benchmark carbon black (Printex 90). Subsequently, the vasomotor function was assessed in wire myographs. In an in vivo study, lean Zucker rats were exposed intragastrically once a week for 10 weeks to vehicle, E171 or E153. Doses were comparable to human daily intake. Vasomotor function...... no differences between groups.Conclusion: Gastrointestinal tract exposure to E171 and E153 was associated with modest albeit statistically significant alterations in the vasocontraction and vasorelaxation responses. Direct particle exposure to aorta rings elicited a similar type of response. The vasomotor...

  9. Identification of the Propionicin F Bacteriocin Immunity Gene (pcfI) and Development of a Food-Grade Cloning System for Propionibacterium freudenreichii▿ †

    Science.gov (United States)

    Brede, Dag Anders; Lothe, Sheba; Salehian, Zhian; Faye, Therese; Nes, Ingolf F.

    2007-01-01

    This report describes the first functional analysis of a bacteriocin immunity gene from Propionibacterium freudenreichii and its use as a selection marker for food-grade cloning. Cloning of the pcfI gene (previously orf5 [located as part of the pcfABC propionicin F operon]) rendered the sensitive host 1,000-fold more tolerant to the propionicin F bacteriocin. The physiochemical properties of the 127-residue large PcfI protein resemble those of membrane-bound immunity proteins from bacteriocin systems found in lactic acid bacteria. The high level of immunity conferred by pcfI allowed its use as a selection marker for plasmid transformation in P. freudenreichii. Electroporation of P. freudenreichii IFO12426 by use of the pcfI expression plasmid pSL102 and propionicin F selection (200 bacteriocin units/ml) yielded 107 transformants/μg DNA. The 2.7-kb P. freudenreichii food-grade cloning vector pSL104 consists of the pLME108 replicon, a multiple cloning site, and pcfI expressed from the constitutive PpampS promoter for selection. The pSL104 vector efficiently facilitated cloning of the propionicin T1 bacteriocin in P. freudenreichii. High-level propionicin T1 production (640 BU/ml) was obtained with the IFO12426 strain, and the food-grade propionicin T1 expression plasmid pSL106 was maintained by ∼91% of the cells over 25 generations in the absence of selection. To the best of our knowledge this is the first report of an efficient cloning system that facilitates the generation of food-grade recombinant P. freudenreichii strains. PMID:17933941

  10. Identification of the propionicin F bacteriocin immunity gene (pcfI) and development of a food-grade cloning system for Propionibacterium freudenreichii.

    Science.gov (United States)

    Brede, Dag Anders; Lothe, Sheba; Salehian, Zhian; Faye, Therese; Nes, Ingolf F

    2007-12-01

    This report describes the first functional analysis of a bacteriocin immunity gene from Propionibacterium freudenreichii and its use as a selection marker for food-grade cloning. Cloning of the pcfI gene (previously orf5 [located as part of the pcfABC propionicin F operon]) rendered the sensitive host 1,000-fold more tolerant to the propionicin F bacteriocin. The physiochemical properties of the 127-residue large PcfI protein resemble those of membrane-bound immunity proteins from bacteriocin systems found in lactic acid bacteria. The high level of immunity conferred by pcfI allowed its use as a selection marker for plasmid transformation in P. freudenreichii. Electroporation of P. freudenreichii IFO12426 by use of the pcfI expression plasmid pSL102 and propionicin F selection (200 bacteriocin units/ml) yielded 10(7) transformants/microg DNA. The 2.7-kb P. freudenreichii food-grade cloning vector pSL104 consists of the pLME108 replicon, a multiple cloning site, and pcfI expressed from the constitutive P(pampS) promoter for selection. The pSL104 vector efficiently facilitated cloning of the propionicin T1 bacteriocin in P. freudenreichii. High-level propionicin T1 production (640 BU/ml) was obtained with the IFO12426 strain, and the food-grade propionicin T1 expression plasmid pSL106 was maintained by approximately 91% of the cells over 25 generations in the absence of selection. To the best of our knowledge this is the first report of an efficient cloning system that facilitates the generation of food-grade recombinant P. freudenreichii strains.

  11. Preparation of submicrometer monodispersed magnetic silica particles using a novel water in oil microemulsion: properties and application for enzyme immobilization.

    Science.gov (United States)

    Tuttolomondo, Maria Victoria; Villanueva, Maria Emilia; Alvarez, Gisela Solange; Desimone, Martín Federico; Díaz, Luis Eduardo

    2013-10-01

    The synthesis of monodispersed magnetic silica nanoparticles (MSN) is described using a water-in-oil reverse microemulsion system that does not require the use of co-surfactants. Sodium silicate, Tween 20 as a neutral surfactant and 1-butanol as the organic phase were used. There are several advantages of the proposed method including a saturation magnetization value of 10 emu/g for the particles obtained, uniformity of size and that they are easily functionalized to bind urease covalently. Moreover, the intra-day, inter-day and long-term stability results confirm that the procedure was successful and the enzyme-linked MSNs were stable over repeated uses and storage retaining more than 75% activity after 4 months.

  12. Migration of dioctyladipate plasticizer from food-grade PVC film into chicken meat products: effect of gamma-radiation

    International Nuclear Information System (INIS)

    Goulas, A.E.; Kontominas, M.G.

    1996-01-01

    Food-grade PVC film containing 28.3% dioctyladipate (DOA) plasticizer was used to wrap chicken meat samples, with and without skin, contained in a polystyrene tray. Samples were then irradiated with gamma-radiation [60Co] at doses equal to 4 kGy and 9 kGy corresponding to ''cold pasteurization''. Irraddiation was carried out at 8-10 degrees C and samples were subsequently stored at 4-5 degrees C. Contaminated chicken meat samples were analysed for DOA at intervals between 7 h and 240 h of contact, using an indirect GC method. Identical non-irradiated (control) samples were also analysed for their DOA content. Results showed no statistically significant differences in migrated amounts of DOA between irradiated and non-irradiated samples. Neither were differences observed between samples irradiated at 4 kGy and 9 kGy. This was supported by identical IR spectra recorded for irradiated and non-irradiated samples and leads to the conclusion that, at such intermediate radiation doses ( < or = kGy), the migration characteristics of PVC film are not affected. DOA migration was found to be time dependent, approaching equilibrium after approximately 170 h for the chicken flesh plus skin samples and 120 h for the chicken flesh samples. The amount of DOA migrated into chicken flesh plus skin samples was significantly greater (3.2-22.3 mg/dm2) than that for chicken flesh samples (0.9-8.9 mg/dm2). After 240 h of sample/film contact under refrigeration, loss of DOA was approximately 35.6% for chicken flesh plus skin samples and 14.3% for chicken flesh samples. Sample spoilage, as demonstrated by off-odour development, occurred after approximately 120 h of refrigerated storage. Diffusion coefficients for DOA were calculated and were found to be lower for chicken flesh (1 x 10(-13) than for flesh plus skin (4.4 x 10(-13)) samples

  13. A mouse mastitis model to study the effects of the intramammary infusion of a food-grade Lactococcus lactis strain.

    Directory of Open Access Journals (Sweden)

    Cristina Camperio

    also found in L. lactis-inoculated glands. The above findings seem to suggest that food-grade L. lactis at a high-inoculum dose such as an overnight culture may elicit a suppurative inflammatory response in the mammary gland, thus becoming a potential mastitis-causing pathogen. Because of the unpredictable potential of L. lactis in acting as a potential mastitis pathogen, this organism cannot be considered a safe treatment for bovine mastitis.

  14. A mouse mastitis model to study the effects of the intramammary infusion of a food-grade Lactococcus lactis strain

    Science.gov (United States)

    Biasibetti, Elena; Frassanito, Paolo; Giovannelli, Carlo; Spuria, Liliana; D’Agostino, Claudia; Tait, Sabrina; Capucchio, Maria Teresa

    2017-01-01

    in L. lactis-inoculated glands. The above findings seem to suggest that food-grade L. lactis at a high-inoculum dose such as an overnight culture may elicit a suppurative inflammatory response in the mammary gland, thus becoming a potential mastitis-causing pathogen. Because of the unpredictable potential of L. lactis in acting as a potential mastitis pathogen, this organism cannot be considered a safe treatment for bovine mastitis. PMID:28873396

  15. A mouse mastitis model to study the effects of the intramammary infusion of a food-grade Lactococcus lactis strain.

    Science.gov (United States)

    Camperio, Cristina; Armas, Federica; Biasibetti, Elena; Frassanito, Paolo; Giovannelli, Carlo; Spuria, Liliana; D'Agostino, Claudia; Tait, Sabrina; Capucchio, Maria Teresa; Marianelli, Cinzia

    2017-01-01

    L. lactis-inoculated glands. The above findings seem to suggest that food-grade L. lactis at a high-inoculum dose such as an overnight culture may elicit a suppurative inflammatory response in the mammary gland, thus becoming a potential mastitis-causing pathogen. Because of the unpredictable potential of L. lactis in acting as a potential mastitis pathogen, this organism cannot be considered a safe treatment for bovine mastitis.

  16. The effect of commercial enzyme preparation-assisted maceration on the yield, quality, and bioactivity of essential oil from waste carrot seeds (Daucus carota L.

    Directory of Open Access Journals (Sweden)

    Śmigielski, K. B.

    2014-12-01

    Full Text Available Eight enzyme preparations were screened with a view to maximizing the yield of carrot seed essential oil. Three of the eight enzyme preparations investigated, lipase from Mucor circinelloides, XPect® pectinase, and Esperase® protease, significantly influenced the amount of essential oil obtained, with Esperase® being the most effective. The Taguchi method was applied to optimize the processing conditions for the Esperase® protease. Under the optimum conditions, the essential oil yield increased by approximately 48%. The main constituent compounds in the oil are: carotol (OeA: 40.80%–OeB: 46.17%, daucol (OeA: 7.35%–OeB: 6.22%, sabinene (OeA: 5.12%–OeB: 6.13%, alpha-pinene (OeA: 4.24%–OeB: 5.11% and geranyl acetate (OeA: 4.50%–OeB: 3.68%. As compared to the control sample, the essential oil obtained from enzyme-pretreated carrot seeds has the same biological activity against Bacillus subtilis and Candida sp., lower activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and higher activity against Aspergillus niger and Penicillium expansum.Ocho preparados enzimáticos fueron seleccionados con el fin de maximizar el rendimiento de aceites esenciales de semillas de zanahoria. Tres de los ocho preparados de las enzimas investigadas, lipasa de Mucor circinelloides, Xpect® pectinasa y Esperase® proteasa, influyeron de manera significativa sobre la cantidad de aceite esencial obtenido, siendo Esperase® el más eficaz. El método de Taguchi se aplicó para optimizar las condiciones del procesamiento para esta última. Bajo las condiciones óptimas, el rendimiento de los aceite esenciales aumentó aproximadamente un 48%. Los principales compuestos constituyentes del aceite son: carotol (OEA: 40.80%–OeB: 46,17%, ducol (OEA: 7,35%–OeB: 6,22%, sabineno (OEA: 5,12%–OeB: 6,13%, alfa-pineno (OEA: 4,24%– OeB: 5,11% y acetato de geranilo (OEA: 4,50%–OeB: 3,68%. En comparación con la muestra control, el

  17. Developing novel one-step processes for obtaining food-grade O/W emulsions from pressurized fluid extracts: processes description, state of the art and perspectives

    OpenAIRE

    SANTOS, Diego Tresinari; MEIRELES, Maria Angela de Almeida

    2015-01-01

    Abstract In this work, a novel on-line process for production of food-grade emulsions containing oily extracts, i.e. oil-in-water (O/W) emulsions, in only one step is presented. This process has been called ESFE, Emulsions from Supercritical Fluid Extraction. With this process, emulsions containing supercritical fluid extracts can be obtained directly from plant materials. The aim in the conception of this process is to propose a new rapid way to obtain emulsions from supercritical fluid extr...

  18. Identification of the Propionicin F Bacteriocin Immunity Gene (pcfI) and Development of a Food-Grade Cloning System for Propionibacterium freudenreichii▿ †

    OpenAIRE

    Brede, Dag Anders; Lothe, Sheba; Salehian, Zhian; Faye, Therese; Nes, Ingolf F.

    2007-01-01

    This report describes the first functional analysis of a bacteriocin immunity gene from Propionibacterium freudenreichii and its use as a selection marker for food-grade cloning. Cloning of the pcfI gene (previously orf5 [located as part of the pcfABC propionicin F operon]) rendered the sensitive host 1,000-fold more tolerant to the propionicin F bacteriocin. The physiochemical properties of the 127-residue large PcfI protein resemble those of membrane-bound immunity proteins from bacteriocin...

  19. Impact of ultraviolet radiation treatments on the physicochemical properties, antioxidants, enzyme activity and microbial load in freshly prepared hand pressed strawberry juice.

    Science.gov (United States)

    Bhat, Rajeev; Stamminger, Rainer

    2015-07-01

    Freshly prepared, hand-pressed strawberry fruit juice was exposed to ultraviolet radiation (254 nm) at room temperature (25 ℃ ± 1 ℃) for 15, 30 and 60 min with 0 min serving as control. Results revealed decrease in pH, total soluble solids and titratable acidity, while colour parameters (L*, a* and b* values) and clarity of juice (% transmittance) increased significantly. All the results corresponded to exposure time to ultraviolet radiation. Bioactive compounds (total phenolics, ascorbic acid and anthocyanins) decreased along with a recorded reduction in polyphenol oxidase enzyme and 1,1-diphenyl-2-picryl hydrazyl radical scavenging activities, which were again dependent on exposure time. Results on the microbial studies showed significant reduction by 2-log cycles in aerobic plate count as well as in total yeast and mould counts. Though negative results were observed for certain parameters, this is the first time it was endeavoured to demonstrate the impact of ultraviolet radiation radiation on freshly prepared, hand-pressed strawberries juice. © The Author(s) 2014.

  20. Evaluation of food grade solvents for lipid extraction and impact of storage temperature on fatty acid composition of edible seaweeds Laminaria digitata (Phaeophyceae) and Palmaria palmata (Rhodophyta).

    Science.gov (United States)

    Schmid, Matthias; Guihéneuf, Freddy; Stengel, Dagmar B

    2016-10-01

    This study evaluated the impact of different food- and non-food grade extraction solvents on yield and fatty acid composition of the lipid extracts of two seaweed species (Palmaria palmata and Laminaria digitata). The application of chloroform/methanol and three different food grade solvents (ethanol, hexane, ethanol/hexane) revealed significant differences in both, extraction yield and fatty acid composition. The extraction efficiency, in terms of yields of total fatty acids (TFA), was in the order: chloroform/methanol>ethanol>hexane>ethanol/hexane for both species. Highest levels of polyunsaturated fatty acids (PUFA) were achieved by the extraction with ethanol. Additionally the effect of storage temperature on the stability of PUFA in ground and freeze-dried seaweed biomass was investigated. Seaweed samples were stored for a total duration of 22months at three different temperatures (-20°C, 4°C and 20°C). Levels of TFA and PUFA were only stable after storage at -20°C for the two seaweed species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. [The rise of enzyme engineering in China].

    Science.gov (United States)

    Li, Gaoxiang

    2015-06-01

    Enzyme engineering is an important part of the modern biotechnology. Industrial biocatalysis is considered the third wave of biotechnology following pharmaceutical and agricultural waves. In 25 years, China has made a mighty advances in enzyme engineering research. This review focuses on enzyme genomics, enzyme proteomics, biosynthesis, microbial conversion and biosensors in the Chinese enzyme engineering symposiums and advances in enzyme preparation industry in China.

  2. Novel Method of Preparation and Activity Research on Arctigenin from Fructus Arctii

    Science.gov (United States)

    Cai, Enbo; Han, Jiahong; Yang, Limin; Zhang, Weiyuan; Zhao, Yan; Chen, Qiulian; Guo, Meng; He, Xinhong

    2018-01-01

    Background: Arctigenin has many pharmacological activities with clinical significance and is derived from Arctium lappa L. However, the present extraction method is inefficient and does not have meaningful industrial production. Objective: A new method to directly prepare arctigenin was established by combining enzyme-assisted extraction and central composite design. Arctigenin's further pharmacological activity was also surveyed in vitro. Materials and Methods: β-D-Glucosidase, a food-grade enzyme, was added directly to the fruits of A. lappa L. to hydrolyze the arctiin to arctigenin, and the obtained samples were subsequently subjected to ethanol (30%, v/v) extraction. The pharmacological activity of the extraction and arctigenin was determined by inhibiting acetylcholinesterase (AChE) and scavenging nitrite. Results: The factors investigated include the enzyme concentration (0.5%–2.5%), ultrasound time (10 min−3 0 min), and extraction temperature (30°C–50°C). From the analysis of the results by Design-Expert (V8.0.6), the optimal extraction conditions were obtained: enzyme concentration (1.4%), ultrasound time (25 min), and extraction temperature (45°C). The highest yield of arctigenin, obtained under the optimal conditions was 6.39%, representing an increase of 28.15% compared to the reference extraction without enzyme processing. The IC50 values of the extraction and arctigenin, respectively, for inhibiting AChE were 0.572 mg/ml and 0.462 mg/ml, and those for nitrite-scavenging were 34.571 mg/ml and 17.49 mg/ml. Conclusions: The results demonstrate that using an enzyme directly in the production is an effective means for extracting arctigenin from Fructus arctii. The extraction has the activities of inhibiting AChE and scavenging nitrite, probably because there has arctigenin in it. It is implied that the extraction and arctigenin could contribute to human health in clinical applications. SUMMARY The new method of adding enzyme directly to the

  3. Novel Method of Preparation and Activity Research on Arctigenin from Fructus Arctii.

    Science.gov (United States)

    Cai, Enbo; Han, Jiahong; Yang, Limin; Zhang, Weiyuan; Zhao, Yan; Chen, Qiulian; Guo, Meng; He, Xinhong

    2018-01-01

    Arctigenin has many pharmacological activities with clinical significance and is derived from Arctium lappa L. However, the present extraction method is inefficient and does not have meaningful industrial production. A new method to directly prepare arctigenin was established by combining enzyme-assisted extraction and central composite design. Arctigenin's further pharmacological activity was also surveyed in vitro . β-D-Glucosidase, a food-grade enzyme, was added directly to the fruits of A. lappa L. to hydrolyze the arctiin to arctigenin, and the obtained samples were subsequently subjected to ethanol (30%, v/v) extraction. The pharmacological activity of the extraction and arctigenin was determined by inhibiting acetylcholinesterase (AChE) and scavenging nitrite. The factors investigated include the enzyme concentration (0.5%-2.5%), ultrasound time (10 min -3 0 min), and extraction temperature (30°C-50°C). From the analysis of the results by Design-Expert (V8.0.6), the optimal extraction conditions were obtained: enzyme concentration (1.4%), ultrasound time (25 min), and extraction temperature (45°C). The highest yield of arctigenin, obtained under the optimal conditions was 6.39%, representing an increase of 28.15% compared to the reference extraction without enzyme processing. The IC 50 values of the extraction and arctigenin, respectively, for inhibiting AChE were 0.572 mg/ml and 0.462 mg/ml, and those for nitrite-scavenging were 34.571 mg/ml and 17.49 mg/ml. The results demonstrate that using an enzyme directly in the production is an effective means for extracting arctigenin from Fructus arctii. The extraction has the activities of inhibiting AChE and scavenging nitrite, probably because there has arctigenin in it. It is implied that the extraction and arctigenin could contribute to human health in clinical applications. The new method of adding enzyme directly to the preparation of arctigenin was carried out instead of preparing arctigenin by two

  4. Remediation of a contaminated soil by Ni+2 after application of biochar prepared from de-inking paper sludge: Influence on enzyme activities

    Science.gov (United States)

    Gascó, G.; Paz-Ferreiro, J.; Araujo, F.; Guerrero, F.; Méndez, A.

    2012-04-01

    In recent years, an increasing proportion of recycled fibres are used in paper industries due to their important environmental and economical benefits. A ton of pulp produced from recycled paper requires 60% less energy to manufacture than a ton of bleached virgin kraft pulp [1]. However, removing the ink, clay, coatings and contaminants from waste paper in order to produce recycled paper creates large amounts of de-inking paper sludge (DPS). Nowadays, more than 200000 t of DPS were produced in Spain. DPS can be used as amendment due to their high organic matter [2] but the high C/N ratio and the heavy metal content can limit its use. For this reason, the preparation of biochar obtained from pyrolysis process for water remediation [3] and soil contaminated by heavy metal can be an valorisation alternative. The main objective of this work is to study the influence of the biochar application prepared from de-inking sewage sludge in the soil enzyme activities of a contaminated soil by Ni+2 at two different concentrations. For this reason, an incubation experiment was performed and several enzymatic activities (dehydrogenase, b-glucosidase, phosphomoesterase and arylsulphatase) were monitored. The study was completed studying the influence of the biochar application in plant-available metals from soil. [1] Thompson C.G. 1992. Recycled Papers. The Essential Guide, MIT Press, Cambridge. [2] Barriga S., Méndez A., Cámara J., Guerrero F., Gascó G. 2010. Agricultural valorisation of de-inking paper sludge as organic amendment in different soils: Thermal study. Journal of Thermal Analysis and Calorimetry 99: 981-986 [3] Méndez A., Barriga S., Fidalgo J.M., Gascó G. 2009. Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water. Journal of Hazardous Materials 165: 736-743.

  5. Preparation of polymeric fibers immobilizing inorganic compounds, enzymes, and extractants designed for radionuclide decontamination, ultrapure water production, and rare-earth metal purification

    International Nuclear Information System (INIS)

    Saito, Kyoichi

    2014-01-01

    To remove and recover targeted ions and molecules at a high rate, inorganic compounds, enzymes, and extractants were immobilized onto a commercially available 6-nylon fiber by radiation-induced graft polymerization and subsequent chemical modifications. Fibrous supports with a smaller diameter provide a larger external interface area with liquids. Modified fibers are fabricated into various shapes such as wound filter and braid according to application sites. First, insoluble cobalt ferrocyanide-impregnated fiber was prepared via precipitation by immersing ferrocyanide ion-bound anion-exchange fiber in cobalt chloride solution. Cobalt ferrocyanide impregnated onto the polymer chain grafted onto the fiber specifically captured cesium ions in seawater. Similarly, sodium titanate impregnated onto a cation-exchange fiber selectively captured strontium ions in seawater. Second, urease was bound by an anion-exchange graft chain, followed by enzymatic cross-linking among urease molecules with transglutaminase. The bed charged with the urease-immobilized fiber exhibited a quantitative hydrolysis of urea at a high space velocity of urea solution. Third, an acidic extractant (HDEHP, bis(2-ethylhexyl) phosphate) was impregnated onto a dodecylamino-group-containing polymer chain grafted onto the 6-nylon fiber. Distribution coefficients of the HDEHP-impregnated fiber for neodymium and dysprosium agreed well with those in n-dodecane. (author)

  6. Self-diffusion nuclear magnetic resonance, microstructure transitions, and solubilization capacity of phytosterols and cholesterol in Winsor IV food-grade microemulsions

    DEFF Research Database (Denmark)

    Spernath, Aviram; Yaghmur, Anan; Aserin, Abraham

    2003-01-01

    Microemulsions are of growing interest to the food industry as vehicles for delivering and enhancing solubilization of natural food supplements with nutritional and health benefits. The incorporation of molecular phytosterols, cholesterol-lowering agents, in food products is of great interest...... to the food industry. In this work is demonstrated the use of water dilutable food-grade microemulsions consisting of ethoxylated sorbitan ester (Tween 60), water, R-(+)-limonene, ethanol, and propylene glycol as vehicles for enhancing the phytosterols solubilization. Phytosterols were solubilized up to 12...... times more than the dissolution capacity of the oil [R-(+)-limonene] for the same compounds. The solubilization capacity of phytosterols and cholesterol along a dilution line in a pseudo-ternary phase diagram [on this dilution line the weight ratio of R-(+)-limonene/ethanol/Tween 60 is constant at 1...

  7. Variables affecting the acceptability of radappertized ground beef products. Effects of food grade phosphates, NaCl, fat level, and grinding methods

    International Nuclear Information System (INIS)

    Cohen, J.S.; Shults, G.W.; Mason, V.C.; Wierbicki, E.

    1977-01-01

    A series of experiments was conducted to determine the effect of different variables on the quality of an irradiated ground beef product. Factors studied included: different food-grade phosphates; NaCl content; fat content; and size of grind. The influence of these variables on the cooking loss (moisture retention), shear press values and sensory scores was studied. The addition of phosphates and NaCl was desirable in controlling cooking losses. The most effective phosphate was tetrasodium pyrophosphate. The addition of NaCl decreased the shear press force required to penetrate the beef patty, i.e., it tenderized the product. Phosphate addition did not affect the shear press force. Increased fat content increased the cooking losses, but did not affect the shear press force. Irradiation with sterilizing doses had a marked effect on decreasing the shear press force

  8. Lactococcus lactis expressing food-grade β-galactosidase alleviates lactose intolerance symptoms in post-weaning Balb/c mice.

    Science.gov (United States)

    Li, Jingjie; Zhang, Wen; Wang, Chuan; Yu, Qian; Dai, Ruirui; Pei, Xiaofang

    2012-12-01

    The endogenous β-galactosidase expressed in intestinal microbes is demonstrated to help humans in lactose usage, and treatment associated with the promotion of beneficial microorganism in the gut is correlated with lactose tolerance. From this point, a kind of recombinant live β-galactosidase delivery system using food-grade protein expression techniques and selected probiotics as vehicle was promoted by us for the purpose of application in lactose intolerance subjects. Previously, a recombinant Lactococcus lactis MG1363 strain expressing food-grade β-galactosidase, the L. lactis MG1363/FGZW, was successfully constructed and evaluated in vitro. This study was conducted to in vivo evaluate its efficacy on alleviating lactose intolerance symptoms in post-weaning Balb/c mice, which were orally administered with 1 × 10⁶ CFU or 1 × 10⁸ CFU of L. lactis MG1363/FGZW daily for 4 weeks before lactose challenge. In comparison with naïve mice, the mice administered with L. lactis MG1363/FGZW showed significant alleviation of diarrhea symptoms in less total feces weight within 6 h post-challenge and suppressed intestinal motility after lactose challenge, although there was no significant increase of β-galactosidase activity in small intestine. The alleviation also correlated with higher species abundance, more Bifidobacterium colonization, and stronger colonization resistance in mice intestinal microflora. Therefore, this recombinant L. lactis strain effectively alleviated diarrhea symptom induced by lactose uptake in lactose intolerance model mice with the probable mechanism of promotion of lactic acid bacteria to differentiate and predominantly colonize in gut microbial community, thus making it a promising probiotic for lactose intolerance subjects.

  9. Validation of a paper-disk approach to facilitate the sensory evaluation of bitterness in dairy protein hydrolysates from a newly developed food-grade fractionation system.

    Science.gov (United States)

    Murray, Niamh M; O'Riordan, Dolores; Jacquier, Jean-Christophe; O'Sullivan, Michael; Cohen, Joshua L; Heymann, Hildegarde; Barile, Daniela; Dallas, David C

    2017-06-01

    Casein-hydrolysates (NaCaH) are desirable functional ingredients, but their bitterness impedes usage in foods. This study sought to validate a paper-disk approach to help evaluate bitterness in NaCaHs and to develop a food-grade approach to separate a NaCaH into distinct fractions, which could be evaluated by a sensory panel. Membrane filtration generated sensory evaluation. Bitterness differences observed in the membrane fractions using this sensory evaluation approach reflected those observed for the same fractions presented as a liquid. The flash-chromatography fractions increased in bitterness with an increase in hydrophobicity, except for the 50% EtOH fraction which had little bitterness. Amino acid analysis of the fractions showed enrichment of different essential amino acids in both the bitter and less bitter fractions. The developed food-grade fractionation system, allowed for a simple and reasonably scaled approach to separating a NaCaH, into physicochemically different fractions that could be evaluated by a sensory panel. The method of sensory evaluation used in this study, in which NaCaH samples are impregnated into paper-disks, provided potential solutions for issues such as sample insolubility and limited quantities of sample. As the impregnated paper-disk samples were dehydrated, their long storage life could also be suitable for sensory evaluations distributed by mail for large consumer studies. The research, in this study, allowed for a greater understanding of the physicochemical basis for bitterness in this NaCaH. As some essential amino acids were enriched in the less bitter fractions, selective removal of bitter fractions could allow for the incorporation of the less bitter NaCaH fractions into food products for added nutritional value, without negatively impacting sensory properties. There is potential for this approach to be applied to other food ingredients with undesirable tastes, such as polyphenols.

  10. Activity assessment of microbial fibrinolytic enzymes.

    Science.gov (United States)

    Kotb, Essam

    2013-08-01

    Conversion of fibrinogen to fibrin inside blood vessels results in thrombosis, leading to myocardial infarction and other cardiovascular diseases. In general, there are four therapy options: surgical operation, intake of antiplatelets, anticoagulants, or fibrinolytic enzymes. Microbial fibrinolytic enzymes have attracted much more attention than typical thrombolytic agents because of the expensive prices and the side effects of the latter. The fibrinolytic enzymes were successively discovered from different microorganisms, the most important among which is the genus Bacillus. Microbial fibrinolytic enzymes, especially those from food-grade microorganisms, have the potential to be developed as functional food additives and drugs to prevent or cure thrombosis and other related diseases. There are several assay methods for these enzymes; this may due to the insolubility of substrate, fibrin. Existing assay methods can be divided into three major groups. The first group consists of assay of fibrinolytic activity with natural proteins as substrates, e.g., fibrin plate methods. The second and third groups of assays are suitable for kinetic studies and are based on the determination of hydrolysis of synthetic peptide esters. This review will deal primarily with the microorganisms that have been reported in literature to produce fibrinolytic enzymes and the first review discussing the methods used to assay the fibrinolytic activity.

  11. Pancreatic Enzymes

    Science.gov (United States)

    ... Contact Us DONATE NOW GENERAL DONATION PURPLESTRIDE Pancreatic enzymes Home Facing Pancreatic Cancer Living with Pancreatic Cancer ... and see a registered dietitian. What are pancreatic enzymes? Pancreatic enzymes help break down fats, proteins and ...

  12. Magnetically responsive enzyme powders

    Energy Technology Data Exchange (ETDEWEB)

    Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

    2015-04-15

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

  13. Ultra structure of oil-in-water emulsions a comparison of different microscopy- and preparation methods

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Loussert, C.; Humbel, B.M.

    of food grade emulsifiers such as whey protein, sodium caseinate and milk phospholipids; layers that are expected to be in the range of only a few nm. Furthermore, the liquid nature and high water content of the samples further complicates the preparation process;especially since water is a major...

  14. Effects of human food grade titanium dioxide nanoparticle dietary exposure on Drosophila melanogaster survival, fecundity, pupation and expression of antioxidant genes.

    Science.gov (United States)

    Jovanović, Boris; Cvetković, Vladimir J; Mitrović, Tatjana Lj

    2016-02-01

    The fruitfly, Drosophila melanogaster was exposed to the human food grade of E171 titanium dioxide (TiO2). This is a special grade of TiO2 which is frequently omitted in nanotoxicology studies dealing with TiO2, yet it is the most relevant grade regarding oral exposure of humans. D. melanogaster larvae were exposed to 0.002 mg mL(-1), 0.02 mg mL(-1), 0.2 mg mL(-1), and 2 mg mL(-1) of TiO2 in feeding medium, and the survival, fecundity, pupation time, and expression of genes involved in oxidative stress response were monitored. TiO2 did not affect survival but significantly increased time to pupation (p TiO2 was present in a significant amount in larvae, but was not transferred to adults during metamorphosis. Two individuals with aberrant phenotype similar to previously described gold nanoparticles induced mutant phenotypes were detected in the group exposed to TiO2. In general, TiO2 showed little toxicity toward D. melanogaster at concentrations relevant to oral exposure of humans. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Food-grade TiO2 impairs intestinal and systemic immune homeostasis, initiates preneoplastic lesions and promotes aberrant crypt development in the rat colon.

    Science.gov (United States)

    Bettini, Sarah; Boutet-Robinet, Elisa; Cartier, Christel; Coméra, Christine; Gaultier, Eric; Dupuy, Jacques; Naud, Nathalie; Taché, Sylviane; Grysan, Patrick; Reguer, Solenn; Thieriet, Nathalie; Réfrégiers, Matthieu; Thiaudière, Dominique; Cravedi, Jean-Pierre; Carrière, Marie; Audinot, Jean-Nicolas; Pierre, Fabrice H; Guzylack-Piriou, Laurence; Houdeau, Eric

    2017-01-20

    Food-grade titanium dioxide (TiO 2 ) containing a nanoscale particle fraction (TiO 2 -NPs) is approved as a white pigment (E171 in Europe) in common foodstuffs, including confectionary. There are growing concerns that daily oral TiO 2 -NP intake is associated with an increased risk of chronic intestinal inflammation and carcinogenesis. In rats orally exposed for one week to E171 at human relevant levels, titanium was detected in the immune cells of Peyer's patches (PP) as observed with the TiO 2 -NP model NM-105. Dendritic cell frequency increased in PP regardless of the TiO 2 treatment, while regulatory T cells involved in dampening inflammatory responses decreased with E171 only, an effect still observed after 100 days of treatment. In all TiO 2 -treated rats, stimulation of immune cells isolated from PP showed a decrease in Thelper (Th)-1 IFN-γ secretion, while splenic Th1/Th17 inflammatory responses sharply increased. E171 or NM-105 for one week did not initiate intestinal inflammation, while a 100-day E171 treatment promoted colon microinflammation and initiated preneoplastic lesions while also fostering the growth of aberrant crypt foci in a chemically induced carcinogenesis model. These data should be considered for risk assessments of the susceptibility to Th17-driven autoimmune diseases and to colorectal cancer in humans exposed to TiO 2 from dietary sources.

  16. Developing novel one-step processes for obtaining food-grade O/W emulsions from pressurized fluid extracts: processes description, state of the art and perspectives

    Directory of Open Access Journals (Sweden)

    Diego Tresinari SANTOS

    2015-01-01

    Full Text Available AbstractIn this work, a novel on-line process for production of food-grade emulsions containing oily extracts, i.e. oil-in-water (O/W emulsions, in only one step is presented. This process has been called ESFE, Emulsions from Supercritical Fluid Extraction. With this process, emulsions containing supercritical fluid extracts can be obtained directly from plant materials. The aim in the conception of this process is to propose a new rapid way to obtain emulsions from supercritical fluid extracts. Nowadays the conventional emulsion formulation method is a two-step procedure, i.e. first supercritical fluid extraction for obtaining an extract; secondly emulsion formulation using another device. Other variation of the process was tested and successfully validated originating a new acronymed process: EPFE (Emulsions from Pressurized Fluid Extractions. Both processes exploit the supercritical CO2-essential oils miscibility, in addition, EPFE process exploits the emulsification properties of saponin-rich pressurized aqueous plant extracts. The feasibility of this latter process was demonstrated using Pfaffia glomerata roots as source of saponin-rich extract, water as extracting solvent and clove essential oil, directly extracted using supercritical CO2, as a model dispersed phase. In addition, examples of pressurized fluid-based coupled processes applied for adding value to food bioactive compounds developed in the past five years are reviewed.

  17. Formulation and Stabilization of Concentrated Edible Oil-in-Water Emulsions Based on Electrostatic Complexes of a Food-Grade Cationic Surfactant (Ethyl Lauroyl Arginate) and Cellulose Nanocrystals.

    Science.gov (United States)

    Bai, Long; Xiang, Wenchao; Huan, Siqi; Rojas, Orlando J

    2018-05-14

    We report on high-internal-phase, oil-in-water Pickering emulsions that are stable against coalescence during storage. Viscous, edible oil (sunflower) was emulsified by combining naturally derived cellulose nanocrystals (CNCs) and a food-grade, biobased cationic surfactant obtained from lauric acid and L-arginine (ethyl lauroyl arginate, LAE). The interactions between CNC and LAE were elucidated by isothermal titration calorimetry (ITC) and supplementary techniques. LAE adsorption on CNC surfaces and its effect on nanoparticle electrostatic stabilization, aggregation state, and emulsifying ability was studied and related to the properties of resultant oil-in-water emulsions. Pickering systems with tunable droplet diameter and stability against oil coalescence during long-term storage were controllably achieved depending on LAE loading. The underlying stabilization mechanism was found to depend on the type of complex formed, the LAE structures adsorbed on the cellulose nanoparticles (as unimer or as adsorbed admicelles), the presence of free LAE in the aqueous phase, and the equivalent alkane number of the oil phase (sunflower and dodecane oils were compared). The results extend the potential of CNC in the formulation of high-quality and edible Pickering emulsions. The functional properties imparted by LAE, a highly effective molecule against food pathogens and spoilage organisms, open new opportunities in food, cosmetics, and pharmaceutical applications, where the presence of CNC plays a critical role in achieving synergistic effects with LAE.

  18. Anthocyanins from purple sweet potato (Ipomoea batatas (L.) Lam.) and their color modulation by the addition of phenolic acids and food-grade phenolic plant extracts.

    Science.gov (United States)

    Gras, Claudia C; Nemetz, Nicole; Carle, Reinhold; Schweiggert, Ralf M

    2017-11-15

    Anthocyanin profiles and contents of three purple sweet potato provenances were investigated by HPLC-DAD-MS n . In contrast to widely uniform profiles, the contents of total (558-2477mg/100gDM) and individual anthocyanins varied widely. Furthermore, quantitative and qualitative effects of intermolecular co-pigmentation were studied by adding chlorogenic and rosmarinic acids, and food-grade phenolic apple and rosemary extracts at various dosages to a diluted purple sweet potato concentrate at pH 0.9, 2.6, 3.6, and 4.6. Addition of co-pigments generally increased pK H estimate -values of anthocyanins from 3.28 (without co-pigments) to up to 4.71, thus substantially broadening the pH range wherein colored forms prevail. The most pronounced hyperchromic shift by up to +50.5% at the absorption maximum was observed at pH 4.6. Simply by blending the co-pigments with purple sweet potato anthocyanins at pH-values ranging from 2.6 to 4.6, purplish-blue, light pink, magenta, brick-red, and intense red hues were accessible as expressed by CIE-L ∗ a ∗ b ∗ color values. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. 7 CFR 58.436 - Rennet, pepsin, other milk clotting enzymes and flavor enzymes.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Rennet, pepsin, other milk clotting enzymes and flavor enzymes. 58.436 Section 58.436 Agriculture Regulations of the Department of Agriculture (Continued... clotting enzymes and flavor enzymes. Enzyme preparations used in the manufacture of cheese shall be safe...

  20. Cellular uptake of beta-carotene from protein stabilized solid lipid nano-particles prepared by homogenization-evaporation method

    Science.gov (United States)

    Using a homogenization-evaporation method, beta-carotene (BC) loaded nano-particles were prepared with different ratios of food-grade sodium caseinate (SC), whey protein isolate (WPI), or soy protein isolate (SPI) to BC and evaluated for their physiochemical stability, in vitro cytotoxicity, and cel...

  1. Enzymes in Fermented Fish.

    Science.gov (United States)

    Giyatmi; Irianto, H E

    Fermented fish products are very popular particularly in Southeast Asian countries. These products have unique characteristics, especially in terms of aroma, flavor, and texture developing during fermentation process. Proteolytic enzymes have a main role in hydrolyzing protein into simpler compounds. Fermentation process of fish relies both on naturally occurring enzymes (in the muscle or the intestinal tract) as well as bacteria. Fermented fish products processed using the whole fish show a different characteristic compared to those prepared from headed and gutted fish. Endogenous enzymes like trypsin, chymotrypsin, elastase, and aminopeptidase are the most involved in the fermentation process. Muscle tissue enzymes like cathepsins, peptidases, transaminases, amidases, amino acid decarboxylases, glutamic dehydrogenases, and related enzymes may also play a role in fish fermentation. Due to the decreased bacterial number during fermentation, contribution of microbial enzymes to proteolysis may be expected prior to salting of fish. Commercial enzymes are supplemented during processing for specific purposes, such as quality improvement and process acceleration. In the case of fish sauce, efforts to accelerate fermentation process and to improve product quality have been studied by addition of enzymes such as papain, bromelain, trypsin, pepsin, and chymotrypsin. © 2017 Elsevier Inc. All rights reserved.

  2. Food-grade TiO2 is trapped by intestinal mucus in vitro but does not impair mucin O-glycosylation and short-chain fatty acid synthesis in vivo: implications for gut barrier protection.

    Science.gov (United States)

    Talbot, Pauline; Radziwill-Bienkowska, Joanna M; Kamphuis, Jasper B J; Steenkeste, Karine; Bettini, Sarah; Robert, Véronique; Noordine, Marie-Louise; Mayeur, Camille; Gaultier, Eric; Langella, Philippe; Robbe-Masselot, Catherine; Houdeau, Eric; Thomas, Muriel; Mercier-Bonin, Muriel

    2018-06-19

    Titanium dioxide (TiO 2 ) particles are commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, the risk of gut barrier disruption is an increasing concern because of the presence of a nano-sized fraction. Food-grade E171 may interact with mucus, a gut barrier protagonist still poorly explored in food nanotoxicology. To test this hypothesis, a comprehensive approach was performed to evaluate in vitro and in vivo interactions between TiO 2 and intestinal mucus, by comparing food-grade E171 with NM-105 (Aeroxyde P25) OECD reference nanomaterial. We tested E171-trapping properties of mucus in vitro using HT29-MTX intestinal epithelial cells. Time-lapse confocal laser scanning microscopy was performed without labeling to avoid modification of the particle surface. Near-UV irradiation of E171 TiO 2 particles at 364 nm resulted in fluorescence emission in the visible range, with a maximum at 510 nm. The penetration of E171 TiO 2 into the mucoid area of HT29-MTX cells was visualized in situ. One hour after exposure, TiO 2 particles accumulated inside "patchy" regions 20 µm above the substratum. The structure of mucus produced by HT29-MTX cells was characterized by MUC5AC immunofluorescence staining. The mucus layer was thin and organized into regular "islands" located approximately 20 µm above the substratum. The region-specific trapping of food-grade TiO 2 particles was attributed to this mucus patchy structure. We compared TiO 2 -mediated effects in vivo in rats after acute or sub-chronic oral daily administration of food-grade E171 and NM-105 at relevant exposure levels for humans. Cecal short-chain fatty acid profiles and gut mucin O-glycosylation patterns remained unchanged, irrespective of treatment. Food-grade TiO 2 is trapped by intestinal mucus in vitro but does not affect mucin O-glycosylation and short-chain fatty acid synthesis in vivo, suggesting the absence of a mucus barrier impairment under "healthy gut

  3. Preparation and characterization of room temperature ionic liquid/single-walled carbon nanotube nanocomposites and their application to the direct electrochemistry of heme-containing proteins/enzymes

    International Nuclear Information System (INIS)

    Du, Pan; Liu, Shuna; Wu, Ping; Cai, Chenxin

    2007-01-01

    This work describes the formation and possible electrochemical application of a novel nanocomposite based on single-walled carbon nanotubes (SWNTs) and imidazolium-based room-temperature ionic liquids (RTILs) of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF 4 , a hydrophilic RTIL) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF 6 , a hydrophobic RTIL). The nanocomposites ([bmim]BF 4 -SWNTs, and [bmim]PF 6 -SWNTs) were formed by simply grinding the SWNTs with the respective RTIL. The results of the X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy indicated that the nanocomposites were formed by adsorption of an imidazolium ion on the surface of SWNTs via the 'cation-π' interaction. SEM images showed that [bmim]BF 4 -SWNTs (or [bmim]PF 6 -SWNTs) nanocomposites could uniformly cover the surface of a glassy carbon (GC) electrode resulting in a RTILs-SWNTs/GC modified electrode with a high stability. The RTILs-SWNTs composite could be readily used as a matrix to immobilize heme-containing proteins/enzymes (myoglobin, cytochrome c, and horseradish peroxidase) without undergoing denaturation, as was verified by UV-vis and circular dichroic (CD) spectroscopic results. The voltammetric results showed that heme-containing proteins/enzymes entrapped in RTILs-SWNTs composites displayed a pair of well-defined, stable redox peaks, which were ascribed to their direct electron-transfer reactions. The results of controlled experiments showed that the positive charged imidazolium ion played a significant effect on the electrochemical parameters, such as the redox peak separation and the value of the formal potentials, etc., of the electron-transfer reaction of non-neutral species dissolved in solution or immobilized on the electrode surface. Further results demonstrated that the heme-containing proteins/enzymes entrapped in RTILs-SWNTs composites could still retain their bioelectrocatalytic activity toward the reduction of oxygen and hydrogen

  4. Method of preparing uridine-diphospho-/sup 14/C-D-glucose of high molar activity and radiochemical purity by enzyme synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, V; Biely, P; Koelbl, J

    1980-06-15

    A new method is described of enzyme synthesis of uridine-diphospho-/sup 14/C-D-glucose of high molar activity. After conversion of the initial /sup 14/C-D-glucose, the accompanying sugar phosphates and nucleoside-5'-phosphates are selectively hydrolyzed by the action of alkaline phosphatase in the presence of phenolphthalein as an indicator. Uridine-diphospho-/sup 14/C-D-glucose is separated by paper chromatography from the reaction mixture thus modified. Synthesis yields range within 75% and 85% relative to the starting /sup 14/C-D-glucose.

  5. SHELF LIFE OF BOVINE MEAT TREATED WITH FOOD GRADE TRISSODIC PHOSPHATE VIDA DE PRATELEIRA DA CARNE BOVINA TRATADA PELO FOSFATO TRISSÓDICO GRAU ALIMENTÍCIO

    Directory of Open Access Journals (Sweden)

    Albenones José de Mesquita

    2007-09-01

    Full Text Available

    To the present study, the capacity of food grade trissodic phosphate to reduce bacterial spoiling and pathogenic effect on bovine meat from three different categories of abattoirs was estimated, as well as shelf life of bovine meat kept under refrigeration. Trissodic phosphate was efficient to reduce bacterial spoiling and pathogenic effect, represented by mesophils and psychrotrophs, indicator microorganisms, fecal coliforms and pathogens such as Staphylococcus aureus and Salmonella. The shelf life of treated bovine meat was influenced by the abattoir category and by the treatment with 10% solution of trissodic phosphate which represented an increase of 26.66%, 27.77% and 31.03% in the durability of meat coming from abattoirs A, B and C, respectively.

    KEY-WORDS: Trissodic phosphate; shelf life; bovine meat.

    No presente estudo verificou-se a capacidade do fosfato trissódico grau alimentício de reduzir a carga bacteriana deteriorante e patogênica da carne bovina proveniente de três categorias diferentes de estabelecimentos de abate, bem como estimou-se a vida do produto mantido sob refrigeração. O fosfato trissódico mostrou-se eficiente na redução da carga bacteriana deteriorante, representada por mesófilos e psicrotróficos, microrganismos indicadores, coliformes fecais e patogênicos como o Staphylococcus aureus e a Salmonella. A vida de prateleira da carne tratada foi influenciada pela categoria do estabelecimento e pelo tratamento com fosfato trissódico em solução a 10% que representou um acréscimo de 26,66%, 27,77% e 31,03% na durabilidade das carnes oriundas dos

  6. Sample preparation in separation of the extracellular chitinolytic enzymes of the human intestinal bacterium Clostridium paraputrificum J4 from the culture fluids

    Czech Academy of Sciences Publication Activity Database

    Tishchenko, Galina; Šimůnek, Jiří; Bartoňová, Hana; Dušková, Jarmila; Dohnálek, Jan; Ponomareva, Evgenia; Tennikova, T.

    2011-01-01

    Roč. 879, č. 22 (2011), s. 2175-2178 ISSN 1570-0232 R&D Projects: GA ČR GA310/09/1407; GA ČR GA525/05/2584 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50450515 Keywords : sample preparation * culture fluids C. paraputrificum J4 * chitinases Subject RIV: EE - Microbiology, Virology Impact factor: 2.888, year: 2011

  7. Preparation of riboflavin specifically labeled in the 5'-hydroxymethyl terminus using a vitamin B2-aldehyde-forming enzyme from Schizophyllum commune

    International Nuclear Information System (INIS)

    Kekelidze, T.N.; Edmondson, D.E.; McCormick, D.B.

    1995-01-01

    A method is described for synthesis of riboflavin selectively labeled in the hydrogens at the 5'-hydroxymethyl position. In this method, a vitamin B 2 -aldehyde-forming enzyme from Schizophyllum commune is used to specifically and completely oxidize the 5'-hydroxymethyl of riboflavin to the 5'-aldehyde. This reaction is monitored spectrophotometrically by the reduction of 2,6-dichlorophenolindophenol at 600 nm. Appearance of aldehyde product was directly quantitated by reverse-phase high-performance liquid chromatography. Product is extracted from the incubation mixture by phenol after saturation with (NH 4 ) 2 SO 4 and then further purified by benzyl alcohol extraction. The 5'-aldehyde is reduced with appropriately labeled sodium borohydride to yield the vitamin specifically labeled in the 5'-hydroxymethyl group. (author)

  8. Cloning and expression of the sucrose phosphorylase gene in Bacillus subtilis and synthesis of kojibiose using the recombinant enzyme.

    Science.gov (United States)

    Wang, Miaomiao; Wu, Jing; Wu, Dan

    2018-02-15

    Kojibiose as a prebiotic and inhibitor of α-glucosidase exhibits potential for a wide range of applications in the food and medicine fields; however, large-scale separation and extraction of kojibiose from nature is difficult. Sucrose phosphorylase (SPase) can be used for the production of kojibiose, and currently, SPase is only heterologously expressed in E. coli, making it unsuitable for use in the food industry. However, Bacillus subtilis is generally considered to be a safe organism potentially useful for SPase expression. Here, for the first time, we heterologously expressed Bifidobacterium adolescentis SPase in a food-grade B. subtilis strain. The results showed that SPase was efficiently secreted into the extracellular medium in the absence of a signal peptide. After culturing the recombinant strain in a 3-L bioreactor, crude SPase yield and activity reached 7.5 g/L and 5.3 U/mL, respectively, the highest levels reported to date. The optimal reaction conditions for kojibiose synthesis catalyzed by recombinant SPase were as follows: 0.5 M sucrose, 0.5 M glucose, 0.02 U enzyme /mg all_substrates , pH 7.0, 50 °C, and 30 h. Furthermore, the substrate-conversion rate reached 40.01%, with kojibiose accounting for 104.45 g/L and selectivity for kojibiose production at 97%. Here, we successfully expressed SPase in B. subtilis in the absence of a signal peptide and demonstrated its secretion into the extracellular medium. Our results indicated high levels of recombinant enzyme expression, with a substrate-conversion rate of 40.01%. These results provide a basis for large-scale preparation of kojibiose by the recombinant SPase.

  9. In vitro analysis of protection of the enzyme bile salt hydrolase against enteric conditions by whey protein-gum arabic microencapsulation.

    Science.gov (United States)

    Lambert, J M; Weinbreck, F; Kleerebezem, M

    2008-09-24

    The interest in efficient intestinal delivery of health-promoting substances is increasing. However, the delivery of vulnerable substances such as enzymes requires specific attention. The transit through the stomach, where the pH is very low, can be detrimental to the enzymatic activity of the protein to be delivered. Here, we describe the microencapsulation of the model enzyme bile salt hydrolase (Bsh) using whey protein-gum arabic microencapsulates for food-grade and targeted enzyme delivery in the proximal region of the small intestine. Furthermore, the efficacy of enteric coating microencapsulates for site-specific enzyme delivery was compared in vitro with living Lactobacillus plantarum WCFS1 bacteria that endogenously produce the Bsh enzyme. Microencapsulates allowed highly effective protection of the enzyme under gastric conditions. Moreover, Bsh release under intestinal conditions appeared to be very efficient, although in the presence of pancreatin, the Bsh activity decreased in time due to proteolytic degradation. In comparison, L. plantarum appeared to be capable to withstand gastric conditions as well as pancreatin challenge. Delivery using encapsulates and live bacteria each have different (dis)advantages that are discussed. In conclusion, live bacteria and food-grade microencapsulates provide alternatives for dedicated enteric delivery of specific enzymes, and the choice of enzyme to be delivered may determine which mode of delivery is most suitable.

  10. Preparation, crystallization and X-ray diffraction analysis to 1.5 Å resolution of rat cysteine dioxygenase, a mononuclear iron enzyme responsible for cysteine thiol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Chad R. [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States); Hao, Quan [MacCHESS at the Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853-8001 (United States); Stipanuk, Martha H., E-mail: mhs6@cornell.edu [Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853-8001 (United States)

    2005-11-01

    Recombinant rat cysteine dioxygenase (CDO) has been expressed, purified and crystallized and X-ray diffraction data have been collected to 1.5 Å resolution. Cysteine dioxygenase (CDO; EC 1.13.11.20) is an ∼23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O{sub 2}, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Å resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Å, α = β = γ = 90°. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  11. Preparation, Crystallization and X-ray Diffraction Analysis to 1.5 A Resolution of Rat Cysteine Dioxygenase, a Mononuclear Iron Enzyme Responsible for Cysteine Thiol Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Simmons,C.; Hao, Q.; Stipanuk, M.

    2005-01-01

    Cysteine dioxygenase (CDO; EC 1.13.11.20) is an {approx}23 kDa non-heme iron metalloenzyme that is responsible for the oxidation of cysteine by O2, yielding cysteinesulfinate. CDO catalyzes the first step in the conversion of cysteine to taurine, as well as the first step in the catabolism of cysteine to pyruvate plus sulfate. Recombinant rat CDO was heterologously expressed, purified and crystallized. The protein was expressed as a fusion protein bearing a polyhistidine tag to facilitate purification, a thioredoxin tag to improve solubility and a factor Xa cleavage site to permit removal of the entire N-terminus, leaving only the 200 amino acids inherent to the native protein. A multi-step purification scheme was used to achieve >95% purity of CDO. The optimal CDO crystals diffracted to 1.5 Angstroms resolution and belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 57.55, c = 123.06 Angstrom, {alpha} = {beta} = {gamma} = 90. CDO shows little homology to any other proteins; therefore, the structure of the enzyme will be determined by ab initio phasing using a selenomethionyl derivative.

  12. Dynamics of proteolytic activity of blood enzymes in combined burn and radiation injury and in its treatment with local cryoeffect and with wound closing preparation RZP-3

    International Nuclear Information System (INIS)

    Gertman, V.Z.

    1982-01-01

    The proteolytic activity of trypsine-like proteases of blood at acute injury period doesn't increase as in animals with mere burn and in animals with nure irradiation as well. It can be explained by the absence of adequate stress reaction of the organism due to the sharp decrease of organism reactivity in case of combined burn and radiation injury. Application of low temperatures and combination of cryogenic effect and RZP-3 preparation promotes proteolytic activity increase in animals with combined burn and radiation injury in the climax of radiation sickness. The normalization of the factor was observed at late periods of the investigation. It can be regarded as recovery of the organism reactivity

  13. Effect of the dose of exogenous fibrolytic enzyme preparations on preingestive fiber hydrolysis, ruminal fermentation, and in vitro digestibility of bermudagrass haylage.

    Science.gov (United States)

    Romero, J J; Zarate, M A; Adesogan, A T

    2015-01-01

    Our objectives were to evaluate the effects of the dose rates of 5 Trichoderma reesei and Aspergillus oryzae exogenous fibrolytic enzymes (EFE; 1A, 2A, 11C, 13D, and 15D) on in vitro digestibility, fermentation characteristics, and preingestive hydrolysis of bermudagrass haylage and to identify the optimal dose of each EFE for subsequent in vitro and in vivo studies. In experiment 1, EFE were diluted in citrate-phosphate buffer (pH 6) and applied in quadruplicate in each of 2 runs at 0× (control), 0.5×, 1×, 2×, and 3×; where 1× was the respective manufacturer-recommended dose (2.25, 2.25, 10, 15, and 15g of EFE/kg of dry matter). The suspension was incubated for 24h at 25°C and for a further 24h at 39°C after the addition of ruminal fluid. In experiment 2, a similar approach to that in experiment 1 was used to evaluate simulated preingestive effects, except that sodium azide (0.02% wt/vol) was added to the EFE solution. The suspension was incubated for 24h at 25°C and then 15mL of water was added before filtration to extract water-soluble compounds. For both experiments, data for each enzyme were analyzed separately as a completely randomized block design with a model that included effects of EFE dose, run, and their interaction. In experiment 1, increasing the EFE dose rate nonlinearly increased the DM digestibility of 1A, 2A, 11C, and 13D and the neutral detergent fiber digestibility (NDFD) of 1A, 2A, 11C, and 13D. Optimal doses of 1A, 2A, 11C, 13D, and 15D, as indicated by the greatest increases in NDFD at the lowest dose tested, were 2×, 2×, 1×, 0.5×, and 0.5×, respectively. Increasing the dose rate of 2A, 11C, and 13D nonlinearly increased concentrations of total volatile fatty acids and propionate (mM), decreased their acetate-to-propionate ratios and linearly decreased those of samples treated with 1A and 15D. In experiment 2, increasing the dose rate of each EFE nonlinearly decreased concentrations of netural detergent fiber; also, increasing

  14. Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

    Science.gov (United States)

    Radziwill-Bienkowska, Joanna M.; Talbot, Pauline; Kamphuis, Jasper B. J.; Robert, Véronique; Cartier, Christel; Fourquaux, Isabelle; Lentzen, Esther; Audinot, Jean-Nicolas; Jamme, Frédéric; Réfrégiers, Matthieu; Bardowski, Jacek K.; Langella, Philippe; Kowalczyk, Magdalena; Houdeau, Eric; Thomas, Muriel; Mercier-Bonin, Muriel

    2018-01-01

    Titanium dioxide (TiO2) is commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, a risk of intestinal barrier disruption, including dysbiosis of the gut microbiota, is increasingly suspected because of the presence of a nano-sized fraction in this additive. We hypothesized that food-grade E171 and Aeroxyde P25 (identical to the NM-105 OECD reference nanomaterial in the European Union Joint Research Centre) interact with both commensal intestinal bacteria and transient food-borne bacteria under non-UV-irradiated conditions. Based on differences in their physicochemical properties, we expect a difference in their respective effects. To test these hypotheses, we chose a panel of eight Gram-positive/Gram-negative bacterial strains, isolated from different biotopes and belonging to the species Escherichia coli, Lactobacillus rhamnosus, Lactococcus lactis (subsp. lactis and cremoris), Streptococcus thermophilus, and Lactobacillus sakei. Bacterial cells were exposed to food-grade E171 vs. P25 in vitro and the interactions were explored with innovative (nano)imaging methods. The ability of bacteria to trap TiO2 was demonstrated using synchrotron UV fluorescence imaging with single cell resolution. Subsequent alterations in the growth profiles were shown, notably for the transient food-borne L. lactis and the commensal intestinal E. coli in contact with food-grade TiO2. However, for both species, the reduction in cell cultivability remained moderate, and the morphological and ultrastructural damages, observed with electron microscopy, were restricted to a small number of cells. E. coli exposed to food-grade TiO2 showed some internalization of TiO2 (7% of cells), observed with high-resolution nano-secondary ion mass spectrometry (Nano-SIMS) chemical imaging. Taken together, these data show that E171 may be trapped by commensal and transient food-borne bacteria within the gut. In return, it may induce some physiological

  15. Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging.

    Science.gov (United States)

    Radziwill-Bienkowska, Joanna M; Talbot, Pauline; Kamphuis, Jasper B J; Robert, Véronique; Cartier, Christel; Fourquaux, Isabelle; Lentzen, Esther; Audinot, Jean-Nicolas; Jamme, Frédéric; Réfrégiers, Matthieu; Bardowski, Jacek K; Langella, Philippe; Kowalczyk, Magdalena; Houdeau, Eric; Thomas, Muriel; Mercier-Bonin, Muriel

    2018-01-01

    Titanium dioxide (TiO 2 ) is commonly used as a food additive (E171 in the EU) for its whitening and opacifying properties. However, a risk of intestinal barrier disruption, including dysbiosis of the gut microbiota, is increasingly suspected because of the presence of a nano-sized fraction in this additive. We hypothesized that food-grade E171 and Aeroxyde P25 (identical to the NM-105 OECD reference nanomaterial in the European Union Joint Research Centre) interact with both commensal intestinal bacteria and transient food-borne bacteria under non-UV-irradiated conditions. Based on differences in their physicochemical properties, we expect a difference in their respective effects. To test these hypotheses, we chose a panel of eight Gram-positive/Gram-negative bacterial strains, isolated from different biotopes and belonging to the species Escherichia coli , Lactobacillus rhamnosus , Lactococcus lactis (subsp. lactis and cremoris ), Streptococcus thermophilus , and Lactobacillus sakei . Bacterial cells were exposed to food-grade E171 vs. P25 in vitro and the interactions were explored with innovative (nano)imaging methods. The ability of bacteria to trap TiO 2 was demonstrated using synchrotron UV fluorescence imaging with single cell resolution. Subsequent alterations in the growth profiles were shown, notably for the transient food-borne L. lactis and the commensal intestinal E. coli in contact with food-grade TiO 2 . However, for both species, the reduction in cell cultivability remained moderate, and the morphological and ultrastructural damages, observed with electron microscopy, were restricted to a small number of cells. E. coli exposed to food-grade TiO 2 showed some internalization of TiO 2 (7% of cells), observed with high-resolution nano-secondary ion mass spectrometry (Nano-SIMS) chemical imaging. Taken together, these data show that E171 may be trapped by commensal and transient food-borne bacteria within the gut. In return, it may induce some

  16. Toxicity of Food-Grade TiO2 to Commensal Intestinal and Transient Food-Borne Bacteria: New Insights Using Nano-SIMS and Synchrotron UV Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Joanna M. Radziwill-Bienkowska

    2018-04-01

    Full Text Available Titanium dioxide (TiO2 is commonly used as a food additive (E171 in the EU for its whitening and opacifying properties. However, a risk of intestinal barrier disruption, including dysbiosis of the gut microbiota, is increasingly suspected because of the presence of a nano-sized fraction in this additive. We hypothesized that food-grade E171 and Aeroxyde P25 (identical to the NM-105 OECD reference nanomaterial in the European Union Joint Research Centre interact with both commensal intestinal bacteria and transient food-borne bacteria under non-UV-irradiated conditions. Based on differences in their physicochemical properties, we expect a difference in their respective effects. To test these hypotheses, we chose a panel of eight Gram-positive/Gram-negative bacterial strains, isolated from different biotopes and belonging to the species Escherichia coli, Lactobacillus rhamnosus, Lactococcus lactis (subsp. lactis and cremoris, Streptococcus thermophilus, and Lactobacillus sakei. Bacterial cells were exposed to food-grade E171 vs. P25 in vitro and the interactions were explored with innovative (nanoimaging methods. The ability of bacteria to trap TiO2 was demonstrated using synchrotron UV fluorescence imaging with single cell resolution. Subsequent alterations in the growth profiles were shown, notably for the transient food-borne L. lactis and the commensal intestinal E. coli in contact with food-grade TiO2. However, for both species, the reduction in cell cultivability remained moderate, and the morphological and ultrastructural damages, observed with electron microscopy, were restricted to a small number of cells. E. coli exposed to food-grade TiO2 showed some internalization of TiO2 (7% of cells, observed with high-resolution nano-secondary ion mass spectrometry (Nano-SIMS chemical imaging. Taken together, these data show that E171 may be trapped by commensal and transient food-borne bacteria within the gut. In return, it may induce some

  17. Preparation and application of unhairing enzyme using solid wastes from the leather industry-an attempt toward internalization of solid wastes within the leather industry.

    Science.gov (United States)

    Ramesh, Renganath Rao; Muralidharan, Vimudha; Palanivel, Saravanan

    2018-01-01

    Usage of the animal fleshing waste as the source of carbon and nitrogen for animal skin unhairing protease (EC 3.4.21) production along with agro-industrial wastes like wheat bran has been investigated. Thermal hydrolysis of delimed fleshing waste for 3 h yielded a fleshing hydrolysate (FH) having a protein content of 20.86 mg/mL and total solids of 46,600 ppm. The FH was lyophilized and spray dried to obtain fleshing hydrolysate powder (FHP) to be used along with wheat bran and rice bran for protease production. The carbon, nitrogen, hydrogen, and sulfur contents of the FHP were found to be 40.1, 13.8, 5.4, and 0.2%. The control solid-state fermented (SSF) medium without FHP showed a maximum activity of only 550 U/g. A maximum protease activity of 956 U/g was obtained by using 6% FHP (taken based on the combined total weight of wheat bran and rice bran) after 96 h of fermentation, resulting in a 1.7-fold increase in the protease activity. The total cost of producing 1 kg of FHP and the cost of producing 1000 kU of protease using FHP along with wheat bran and rice bran were found to be USD 24.62 and USD 2.08, respectively; 25% of SSF protease along with 40% water was found to be capable of unhairing the sheepskins in 7 h eliminating the hazardous conventional lime sulfide unhairing system. Thus, the leather industry's solid waste internalized for the production of unhairing enzyme resulted in a sustainable solution for pollution problems. Graphical abstract ᅟ.

  18. Enzyme stabilization for pesticide degradation

    Energy Technology Data Exchange (ETDEWEB)

    Rivers, D.B.; Frazer, F.R. III; Mason, D.W.; Tice, T.R.

    1988-01-01

    Enzymes offer inherent advantages and limitations as active components of formulations used to decontaminate soil and equipment contaminated with toxic materials such as pesticides. Because of the catalytic nature of enzymes, each molecule of enzyme has the potential to destroy countless molecules of a contaminating toxic compound. This degradation takes place under mild environmental conditions of pH, temperature, pressure, and solvent. The basic limitation of enzymes is their degree of stability during storage and application conditions. Stabilizing methods such as the use of additives, covalent crosslinking, covalent attachment, gel entrapment, and microencapsulation have been directed developing an enzyme preparation that is stable under extremes of pH, temperature, and exposure to organic solvents. Initial studies were conducted using the model enzymes subtilisin and horseradish peroxidase.

  19. Cellulolytic enzyme compositions and uses thereof

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Prashant; Gaspar, Armindo Ribiero; Croonenberghs, James; Binder, Thomas P.

    2017-07-25

    The present invention relates enzyme composition comprising a cellulolytic preparation and an acetylxylan esterase (AXE); and the used of cellulolytic enzyme compositions for hydrolyzing acetylated cellulosic material. Finally the invention also relates to processes of producing fermentation products from acetylated cellulosic materials using a cellulolytic enzyme composition of the invention.

  20. Immobilization of Enzymes in Polymer Supports.

    Science.gov (United States)

    Conlon, Hugh D.; Walt, David R.

    1986-01-01

    Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

  1. Cloning, Expression, and Chromosomal Stabilization of the Propionibacterium shermanii Proline Iminopeptidase Gene (pip) for Food-Grade Application in Lactococcus lactis

    NARCIS (Netherlands)

    Leenhouts, Kees; Bolhuis, Albert; Boot, Johan; Deutz, Inge; Toonen, Marjolein; Venema, Gerard; Kok, Jan; Ledeboer, Aat

    1998-01-01

    Proline iminopeptidase produced by Propionibacterium shermanii plays an essential role in the flavor development of Swiss-type cheeses. The enzyme (Pip) was purified and characterized, and the gene (pip) was cloned and expressed in Escherichia coli and Lactococcus lactis, the latter species being an

  2. Evaluation of two Taenia solium cysticercal antigenic preparations (vesicular fluid and a glycoprotein fraction with affinity for lentil lectin for the immunodiagnosis of neurocysticercosis by enzyme-linked immunosorbent assay (ELISA

    Directory of Open Access Journals (Sweden)

    Lisandra Akemi Suzuki

    2011-06-01

    Full Text Available OBJECTIVE: To evaluate the performance of two antigenic preparations (vesicular fluid - VF and a glycoprotein fraction, LLa-Gp fraction, purified from a whole parasite extract by lentil lectin affinity chromatography from Taenia solium cysticerci for the immunodiagnosis of neurocysticercosis. METHOD: Fifty-six cerebrospinal fluid (CSF samples (22 from patients with neurocysticercosis and 34 from patients with other neurological disorders and 57 serum samples (22 from patients with neurocysticercosis, 18 from patients with other infections and 17 from presumably healthy persons were assayed for anticysticercal IgG antibodies with an enzyme-linked immunosorbent assay (ELISA. RESULTS: The VF ELISA showed 100% sensitivity and specificity in CSF and serum samples, whereas the sensitivity and specificity of the LLa-Gp ELISA were, respectively, 90.9% and 97.1%, with the CSF samples and 95.5% and 100% with serum samples. There was no significant difference in the sensitivity and specificity of the two antigenic preparations used to screen CSF and serum samples. CONCLUSION: Considering the complexity and high cost of obtaining the LLa-Gp fraction, VF could be more suitable for screening specific antibodies by ELISA in CSF and serum samples from patients with neurocysticercosis.

  3. Enzyme Mimics: Advances and Applications.

    Science.gov (United States)

    Kuah, Evelyn; Toh, Seraphina; Yee, Jessica; Ma, Qian; Gao, Zhiqiang

    2016-06-13

    Enzyme mimics or artificial enzymes are a class of catalysts that have been actively pursued for decades and have heralded much interest as potentially viable alternatives to natural enzymes. Aside from having catalytic activities similar to their natural counterparts, enzyme mimics have the desired advantages of tunable structures and catalytic efficiencies, excellent tolerance to experimental conditions, lower cost, and purely synthetic routes to their preparation. Although still in the midst of development, impressive advances have already been made. Enzyme mimics have shown immense potential in the catalysis of a wide range of chemical and biological reactions, the development of chemical and biological sensing and anti-biofouling systems, and the production of pharmaceuticals and clean fuels. This Review concerns the development of various types of enzyme mimics, namely polymeric and dendrimeric, supramolecular, nanoparticulate and proteinic enzyme mimics, with an emphasis on their synthesis, catalytic properties and technical applications. It provides an introduction to enzyme mimics and a comprehensive summary of the advances and current standings of their applications, and seeks to inspire researchers to perfect the design and synthesis of enzyme mimics and to tailor their functionality for a much wider range of applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Applications of Microbial Enzymes in Food Industry

    Directory of Open Access Journals (Sweden)

    Binod Parameswaran

    2018-01-01

    Full Text Available The use of enzymes or microorganisms in food preparations is an age-old process. With the advancement of technology, novel enzymes with wide range of applications and specificity have been developed and new application areas are still being explored. Microorganisms such as bacteria, yeast and fungi and their enzymes are widely used in several food preparations for improving the taste and texture and they offer huge economic benefits to industries. Microbial enzymes are the preferred source to plants or animals due to several advantages such as easy, cost-effective and consistent production. The present review discusses the recent advancement in enzyme technology for food industries. A comprehensive list of enzymes used in food processing, the microbial source of these enzymes and the wide range of their application are discussed.

  5. On the use of differential solubility in aqueous ethanol solutions to narrow the DP range of food-grade starch hydrolysis products.

    Science.gov (United States)

    Balto, Amy S; Lapis, Trina J; Silver, Rachel K; Ferreira, Andrew J; Beaudry, Christopher M; Lim, Juyun; Penner, Michael H

    2016-04-15

    Considerable research is focused on understanding the functionality of starch hydrolysis products (SHP) consisting of glucose, maltose, maltooligosaccharides (MOS), and maltopolysaccharides (MPS). A confounding factor in this research is the high molecular dispersity of commercially available SHP. The study presented herein characterizes a flexible fractionation approach for lowering the dispersity of such products. This was accomplished by fractionating a corn syrup solids (CSS) preparation based on the differential solubility of its component saccharides in aqueous-ethanol solutions. Products obtained from selected fractionations were characterized with respect to degree of polymerization (DP; liquid chromatography), dextrose equivalency (reducing sugar assays), and prevalence of branching (NMR). Glucose and maltose were preferentially removed from CSS using high (⩾90%) ethanol extractants. Preparations with relatively narrow ranges of MOS, lower DP MPS, and higher DP MPS were obtained through repetitive 70%-ethanol extractions. Linear, as opposed to branched, MOS and MPS were preferentially extracted under all conditions tested. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Transcriptional regulation of the xylanolytic enzyme system of Aspergillus

    NARCIS (Netherlands)

    Peij, van N.N.M.E.

    1999-01-01

    Filamentous fungi, such as Aspergillus niger , produce high levels of polysaccharide degrading enzymes and are frequently used as production organisms for industrial enzyme preparations. The application of these polysaccharidases as xylanases and cellulases comprises

  7. Enzymes in Poultry and Swine Nutrition

    International Development Research Centre (IDRC) Digital Library (Canada)

    Poultry production in China and the potential for using enzyme preparations .... The feed manufacturers produce about 310 × 106t of high-quality feed, saving about 30%, ...... Chickens and experimental designs used in the three experiments.

  8. Enzyme-MOF (metal-organic framework) composites.

    Science.gov (United States)

    Lian, Xizhen; Fang, Yu; Joseph, Elizabeth; Wang, Qi; Li, Jialuo; Banerjee, Sayan; Lollar, Christina; Wang, Xuan; Zhou, Hong-Cai

    2017-06-06

    The ex vivo application of enzymes in various processes, especially via enzyme immobilization techniques, has been extensively studied in recent years in order to enhance the recyclability of enzymes, to minimize enzyme contamination in the product, and to explore novel horizons for enzymes in biomedical applications. Possessing remarkable amenability in structural design of the frameworks as well as almost unparalelled surface tunability, Metal-Organic Frameworks (MOFs) have been gaining popularity as candidates for enzyme immobilization platforms. Many MOF-enzyme composites have achieved unprecedented results, far outperforming free enzymes in many aspects. This review summarizes recent developments of MOF-enzyme composites with special emphasis on preparative techniques and the synergistic effects of enzymes and MOFs. The applications of MOF-enzyme composites, primarily in transferation, catalysis and sensing, are presented as well. The enhancement of enzymatic activity of the composites over free enzymes in biologically incompatible conditions is emphasized in many cases.

  9. Preparation and Characterization of Astaxanthin Nanoparticles by Solvent-Diffusion Technique

    International Nuclear Information System (INIS)

    Anarjan, N.; Tan, C.P.

    2011-01-01

    In this work, astaxanthin nanoparticles were prepared in aqueous media using solvent-diffusion technique. Sodium caseinate, gelatin, Polysorbate 20 and gum Arabic were selected as different food grade surface active molecules for the stabilization of the produced nanoparticles. Results showed that among produced astaxanthin nanoparticles, the Polysorbate 20-stabilized nanoparticles showed the smallest particle size; gum Arabic-stabilized nanoparticles had the smallest polydispersity index and highest physical stability in simulated gastric fluid (SGF); and those stabilized using gelatin had the highest zeta potential. Sodium caseinate stabilized nanoparticles had the highest astaxanthin content in fresh samples as compared to other prepared nano dispersions. (author)

  10. Enzyme activity assay of glycoprotein enzymes based on a boronate affinity molecularly imprinted 96-well microplate.

    Science.gov (United States)

    Bi, Xiaodong; Liu, Zhen

    2014-12-16

    Enzyme activity assay is an important method in clinical diagnostics. However, conventional enzyme activity assay suffers from apparent interference from the sample matrix. Herein, we present a new format of enzyme activity assay that can effectively eliminate the effects of the sample matrix. The key is a 96-well microplate modified with molecularly imprinted polymer (MIP) prepared according to a newly proposed method called boronate affinity-based oriented surface imprinting. Alkaline phosphatase (ALP), a glycoprotein enzyme that has been routinely used as an indicator for several diseases in clinical tests, was taken as a representative target enzyme. The prepared MIP exhibited strong affinity toward the template enzyme (with a dissociation constant of 10(-10) M) as well as superb tolerance for interference. Thus, the enzyme molecules in a complicated sample matrix could be specifically captured and cleaned up for enzyme activity assay, which eliminated the interference from the sample matrix. On the other hand, because the boronate affinity MIP could well retain the enzymatic activity of glycoprotein enzymes, the enzyme captured by the MIP was directly used for activity assay. Thus, additional assay time and possible enzyme or activity loss due to an enzyme release step required by other methods were avoided. Assay of ALP in human serum was successfully demonstrated, suggesting a promising prospect of the proposed method in real-world applications.

  11. Enzyme detection by microfluidics

    DEFF Research Database (Denmark)

    2013-01-01

    Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

  12. Elevated Liver Enzymes

    Science.gov (United States)

    Symptoms Elevated liver enzymes By Mayo Clinic Staff Elevated liver enzymes may indicate inflammation or damage to cells in the liver. Inflamed or ... than normal amounts of certain chemicals, including liver enzymes, into the bloodstream, which can result in elevated ...

  13. Increased Production of Food-Grade d-Tagatose from d-Galactose by Permeabilized and Immobilized Cells of Corynebacterium glutamicum, a GRAS Host, Expressing d-Galactose Isomerase from Geobacillus thermodenitrificans.

    Science.gov (United States)

    Shin, Kyung-Chul; Sim, Dong-Hyun; Seo, Min-Ju; Oh, Deok-Kun

    2016-11-02

    The generally recognized as safe microorganism Corynebacterium glutamicum expressing Geobacillus thermodenitrificans d-galactose isomerase (d-GaI) was an efficient host for the production of d-tagatose, a functional sweetener. The d-tagatose production at 500 g/L d-galactose by the host was 1.4-fold higher than that by Escherichia coli expressing d-GaI. The d-tagatose-producing activity of permeabilized C. glutamicum (PCG) cells treated with 1% (w/v) Triton X-100 was 2.1-fold higher than that of untreated cells. Permeabilized and immobilized C. glutamicum (PICG) cells in 3% (w/v) alginate showed a 3.1-fold longer half-life at 50 °C and 3.1-fold higher total d-tagatose concentration in repeated batch reactions than PCG cells. PICG cells, which produced 165 g/L d-tagatose after 3 h, with a conversion of 55% (w/w) and a productivity of 55 g/L/h, showed significantly higher d-tagatose productivity than that reported for other cells. Thus, d-tagatose production by PICG cells may be an economical process to produce food-grade d-tagatose.

  14. Kinetics of biofilm formation and desiccation survival of Listeria monocytogenes in single and dual species biofilms with Pseudomonas fluorescens, Serratia proteamaculans or Shewanella baltica on food-grade stainless steel surfaces.

    Science.gov (United States)

    Daneshvar Alavi, Hessam Edin; Truelstrup Hansen, Lisbeth

    2013-01-01

    This study investigated the dynamics of static biofilm formation (100% RH, 15 °C, 48-72 h) and desiccation survival (43% RH, 15 °C, 21 days) of Listeria monocytogenes, in dual species biofilms with the common spoilage bacteria, Pseudomonas fluorescens, Serratia proteamaculans and Shewanella baltica, on the surface of food grade stainless steel. The Gram-negative bacteria reduced the maximum biofilm population of L. monocytogenes in dual species biofilms and increased its inactivation during desiccation. However, due to the higher desiccation resistance of Listeria relative to P. fluorescens and S. baltica, the pathogen survived in greater final numbers. In contrast, S. proteamaculans outcompeted the pathogen during the biofilm formation and exhibited similar desiccation survival, causing the N21 days of Serratia to be ca 3 Log10(CFU cm(-2)) greater than that of Listeria in the dual species biofilm. Microscopy revealed biofilm morphologies with variable amounts of exopolymeric substance and the presence of separate microcolonies. Under these simulated food plant conditions, the fate of L. monocytogenes during formation of mixed biofilms and desiccation depended on the implicit characteristics of the co-cultured bacterium.

  15. Magnetic enzyme reactors for isolation and study of heterogeneous glycoproteins

    International Nuclear Information System (INIS)

    Korecka, Lucie; Jezova, Jana; Bilkova, Zuzana; Benes, Milan; Horak, Daniel; Hradcova, Olga; Slovakova, Marcela; Viovy, Jean-Louis

    2005-01-01

    The newly developed magnetic micro- and nanoparticles with defined hydrophobicity and porosity were used for the preparation of magnetic enzyme reactors. Magnetic particles with immobilized proteolytic enzymes trypsin, chymotrypsin and papain and with enzyme neuraminidase were used to study the structure of heterogeneous glycoproteins. Factors such as the type of carrier, immobilization procedure, operational and storage stability, and experimental conditions were optimized

  16. Depolymerization of chitosan by enzymes from the digestive tract of ...

    African Journals Online (AJOL)

    A complex of enzymes was isolated in a preparation derived from the digestive tract of sea cucumber, Stichopus japonicus. Hydrolysis of chitosan using this enzyme preparation decreased its molecular weight (Mw), increased its water solubility and produced water-soluble chitosan (WSC). The conditions for hydrolysis were ...

  17. Food-grade electrospinning of proteins

    NARCIS (Netherlands)

    Nieuwland, M.; Geerdink, P.; Brier, P.; Eijnden, P. van den; Henket, J.T.M.M.; Langelaan, M.L.P.; Stroeks, N.; Deventer, H.C. van; Martin, A.H.

    2013-01-01

    Developing non-meat food products with an appealing structure is a challenge. In this study, we investigate the possibility to produce thin fibrils as building blocks for texturally interesting meat replacers. The technique applied is electrospinning—a technique which produces thin fibrilswith a

  18. Biotechnological potential of natural food grade biocolorants

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... The color from bright green spinach, ruby red straw- berry, and deep orange .... chromate, copper sulphate) may cause serious health problems (FDA/IFIC .... tionary (soft and hard candy), fish and meat products, fruit products ...

  19. Biotechnological potential of natural food grade biocolorants ...

    African Journals Online (AJOL)

    Color becomes the most sensitive part of any commodity not only for its appeal but also it enhances consumer acceptability. In addition, the color of a food substance is important to indicate its freshness and safety that are also indices of good aesthetic and sensorial values. For natural color and additives, adherence to the ...

  20. Enzymes from Higher Eukaryotes for Industrial Biocatalysis

    Directory of Open Access Journals (Sweden)

    Zhibin Liu

    2004-01-01

    Full Text Available The industrial production of fine chemicals, feed and food ingredients, pharmaceuticals, agrochemicals and their respective intermediates relies on an increasing application of biocatalysis, i.e. on enzyme or whole-cell catalyzed conversions of molecules. Simple procedures for discovery, cloning and over-expression as well as fast growth favour fungi, yeasts and especially bacteria as sources of biocatalysts. Higher eukaryotes also harbour an almost unlimited number of potential biocatalysts, although to date the limited supply of enzymes, the high heterogeneity of enzyme preparations and the hazard of infectious contaminants keep some interesting candidates out of reach for industrial bioprocesses. In the past only a few animal and plant enzymes from agricultural waste materials were employed in food processing. The use of bacterial expression strains or non-conventional yeasts for the heterologous production of efficient eukaryotic enzymes can overcome the bottleneck in enzyme supply and provide sufficient amounts of homogenous enzyme preparations for reliable and economically feasible applications at large scale. Ideal enzymatic processes represent an environmentally friendly, »near-to-completion« conversion of (mostly non-natural substrates to pure products. Recent developments demonstrate the commercial feasibility of large-scale biocatalytic processes employing enzymes from higher eukaryotes (e.g. plants, animals and also their usefulness in some small-scale industrial applications.

  1. Enzymic oxidation of carbon monoxide. II

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, T

    1959-01-01

    An enzyme which catalyzes the oxidation of carbon monoxide into carbon dioxide was obtained in a cell free state from Desulfovibrio desulfuricans. The enzyme activity was assayed manometrically by measuring the rate of gas uptake under the atmosphere of carbon monoxide in the presence of benzyl-viologen as an oxidant. The optimum pH range was 7 to 8. The activity was slightly suppressed by illumination. The enzyme was more stable than hydrogenase or formate dehydrogenase against the heat treatment, suggesting that it is a different entity from these enzymes. In the absence of an added oxidant, the enzyme preparation produced hydrogen gas under the atmosphere of carbon monoxide. The phenomenon can be explained assuming the reductive decomposition of water. 17 references, 4 figures, 2 tables.

  2. ENZYME RESISTANCE OF GENETICALLY MODIFIED STARCH POTATOES

    Directory of Open Access Journals (Sweden)

    A. Sh. Mannapova

    2015-01-01

    Full Text Available Here in this article the justification of expediency of enzyme resistant starch use in therapeutic food products is presented . Enzyme resistant starch is capable to resist to enzymatic hydrolysis in a small intestine of a person, has a low glycemic index, leads to decrease of postprandial concentration of glucose, cholesterol, triglycerides in blood and insulin reaction, to improvement of sensitivity of all organism to insulin, to increase in sense of fulness and to reduction of adjournment of fats. Resistant starch makes bifidogenшс impact on microflora of a intestine of the person, leads to increase of a quantity of lactobacillus and bifidobacterium and to increased production of butyric acid in a large intestine. In this regard the enzyme resistant starch is an important component in food for prevention and curing of human diseases such as diabetes, obesity, colitis, a cancer of large and direct intestine. One method is specified by authors for imitation of starch digestion in a human body. This method is based on the definition of an enzyme resistance of starch in vitro by its hydrolysis to glucose with application of a glucoamylase and digestive enzyme preparation Pancreatin. This method is used in researches of an enzyme resistance of starch, of genetically modified potato, high amylose corn starch Hi-Maize 1043 and HYLON VII (National Starch Food Innovation, USA, amylopectin and amylose. It is shown that the enzyme resistance of the starch emitted from genetically modified potatoes conforms to the enzyme resistance of the high amylose corn starch “Hi-Maize 1043 and HYLON VII starch”, (National Starch Food Innovation, the USA relating to the II type of enzyme resistant starch. It is established that amylopectin doesn't have the enzyme resistant properties. The results of researches are presented. They allow us to make the following conclusion: amylose in comparison with amylopectin possesses higher enzyme resistance and gives to

  3. Enzyme inhibition by iminosugars

    DEFF Research Database (Denmark)

    López, Óscar; Qing, Feng-Ling; Pedersen, Christian Marcus

    2013-01-01

    Imino- and azasugar glycosidase inhibitors display pH dependant inhibition reflecting that both the inhibitor and the enzyme active site have groups that change protonation state with pH. With the enzyme having two acidic groups and the inhibitor one basic group, enzyme-inhibitor complexes...

  4. Preparation of organogel with tea polyphenols complex for enhancing the antioxidation properties of edible oil.

    Science.gov (United States)

    Shi, Rong; Zhang, Qiuyue; Vriesekoop, Frank; Yuan, Qipeng; Liang, Hao

    2014-08-20

    Food-grade organogels are semisolid systems with immobilized liquid edible oil in a three-dimensional network of self-assembled gelators, and they are supposed to have a broad range of potential applications in food industries. In this work, an edible organogel with tea polyphenols was developed, which possesses a highly effective antioxidative function. To enhance the dispersibility of the tea polyphenols in the oil phase, a solid lipid-surfactant-tea polyphenols complex (organogel complex) was first prepared according to a novel method. Then, a food-grade organogel was prepared by mixing this organogel complex with fresh peanut oil. Compared with adding free tea polyphenols, the organogel complex could be more homogeneously distributed in the prepared organogel system, especially under heating condition. Furthermore, the organogel loading of tea polyphenols performed a 2.5-fold higher antioxidation compared with other chemically synthesized antioxidants (butylated hydroxytoluene and propyl gallate) by evaluating the peroxide value of the fresh peanut oil based organogel in accelerated oxidation conditions.

  5. 21 CFR 184.1027 - Mixed carbohydrase and protease enzyme product.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Mixed carbohydrase and protease enzyme product. 184... RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 184.1027 Mixed carbohydrase and protease enzyme product. (a) Mixed carbohydrase and protease enzyme product is an enzyme preparation that includes...

  6. Enzymes for improved biomass conversion

    Science.gov (United States)

    Brunecky, Roman; Himmel, Michael E.

    2016-02-02

    Disclosed herein are enzymes and combinations of the enzymes useful for the hydrolysis of cellulose and the conversion of biomass. Methods of degrading cellulose and biomass using enzymes and cocktails of enzymes are also disclosed.

  7. growth and extracellular enzyme production by microorganisms

    African Journals Online (AJOL)

    Okorie

    2013-06-26

    Jun 26, 2013 ... 1Federal Institute of Industrial Research Oshodi, Lagos, Nigeria. 2Department of ... of Bacillus subtilis (Bs2) were able to produce lipase enzyme. The study ... However, most commercial starter cultures originated from those ... The traditional method of preparing Ugba was employed in the laboratory to ...

  8. Immobilized enzymes and cells

    Energy Technology Data Exchange (ETDEWEB)

    Bucke, C; Wiseman, A

    1981-04-04

    This article reviews the current state of the art of enzyme and cell immobilization and suggests advances which might be made during the 1980's. Current uses of immobilized enzymes include the use of glucoamylase in the production of glucose syrups from starch and glucose isomerase in the production of high fructose corn syrup. Possibilities for future uses of immobilized enzymes and cells include the utilization of whey and the production of ethanol.

  9. Profiling the orphan enzymes

    Science.gov (United States)

    2014-01-01

    The emergence of Next Generation Sequencing generates an incredible amount of sequence and great potential for new enzyme discovery. Despite this huge amount of data and the profusion of bioinformatic methods for function prediction, a large part of known enzyme activities is still lacking an associated protein sequence. These particular activities are called “orphan enzymes”. The present review proposes an update of previous surveys on orphan enzymes by mining the current content of public databases. While the percentage of orphan enzyme activities has decreased from 38% to 22% in ten years, there are still more than 1,000 orphans among the 5,000 entries of the Enzyme Commission (EC) classification. Taking into account all the reactions present in metabolic databases, this proportion dramatically increases to reach nearly 50% of orphans and many of them are not associated to a known pathway. We extended our survey to “local orphan enzymes” that are activities which have no representative sequence in a given clade, but have at least one in organisms belonging to other clades. We observe an important bias in Archaea and find that in general more than 30% of the EC activities have incomplete sequence information in at least one superkingdom. To estimate if candidate proteins for local orphans could be retrieved by homology search, we applied a simple strategy based on the PRIAM software and noticed that candidates may be proposed for an important fraction of local orphan enzymes. Finally, by studying relation between protein domains and catalyzed activities, it appears that newly discovered enzymes are mostly associated with already known enzyme domains. Thus, the exploration of the promiscuity and the multifunctional aspect of known enzyme families may solve part of the orphan enzyme issue. We conclude this review with a presentation of recent initiatives in finding proteins for orphan enzymes and in extending the enzyme world by the discovery of new

  10. Lignin-degrading enzyme activities.

    Science.gov (United States)

    Chen, Yi-ru; Sarkanen, Simo; Wang, Yun-Yan

    2012-01-01

    Over the past three decades, the activities of four kinds of enzyme have been purported to furnish the mechanistic foundations for macromolecular lignin depolymerization in decaying plant cell walls. The pertinent fungal enzymes comprise lignin peroxidase (with a relatively high redox potential), manganese peroxidase, an alkyl aryl etherase, and laccase. The peroxidases and laccase, but not the etherase, are expressed extracellularly by white-rot fungi. A number of these microorganisms exhibit a marked preference toward lignin in their degradation of lignocellulose. Interestingly, some white-rot fungi secrete both kinds of peroxidase but no laccase, while others that are equally effective express extracellular laccase activity but no peroxidases. Actually, none of these enzymes has been reported to possess significant depolymerase activity toward macromolecular lignin substrates that are derived with little chemical modification from the native biopolymer. Here, the assays commonly employed for monitoring the traditional fungal peroxidases, alkyl aryl etherase, and laccase are described in their respective contexts. A soluble native polymeric substrate that can be isolated directly from a conventional milled-wood lignin preparation is characterized in relation to its utility in next-generation lignin-depolymerase assays.

  11. Importance of the rate of hydration of pharmaceutical preparations of guar gum; a new in vitro monitoring method.

    Science.gov (United States)

    Ellis, P R; Morris, E R

    1991-05-01

    Dietary supplements of guar gum are known to improve blood glucose control in diabetic patients. The efficacy of guar is probably dependent mainly upon its capacity to hydrate rapidly and thus to increase viscosity in the small intestine post-prandially. Measurement of the rate of hydration in vitro might therefore be a useful index of the effectiveness of guar formulations. A simple method for monitoring the hydration rate of guar gum has been developed, which involves measuring the changes in viscosity at discrete time intervals over a period of 5 h using a Brookfield RVT rotoviscometer. Six different samples of guar gum (four pharmaceutical preparations and two food grades of guar flour) were hydrated in sealed glass jars rotated at 6 rev min-1 in order to prevent particle aggregation. Marked differences in hydration rate and ultimate (maximum) viscosity between the different guar samples were observed. Three of the four pharmaceutical preparations were lower in viscosity than the food grades of guar flour during the first 60 min of hydration. Two of the preparations hydrated so slowly that even after 5 h they attained viscosity levels of only 60% of their ultimate viscosity. These results may explain why some guar gum preparations are clinically ineffective.

  12. Enzymes: The possibility of production and applications

    Directory of Open Access Journals (Sweden)

    Petronijević Živomir B.

    2003-01-01

    Full Text Available Enzymes are biological catalysts with increasing application in the food pharmaceutical, cosmetic, textile and chemical industry. They are also important as reagents in chemical analysis, leather fabrications and as targets for the design of new drugs. Keeping in mind the growing need to replace classical chemical processes by alternative ones, because of ever growing environmental pollution, it is important that enzyme and other biotechnological processes are economical. Therefore, price decrease and stability and enzyme preparation efficiency increase are required more and more. This paper presents a short review of methods for yield increase and the improvement of the quality of enzyme products as commercial products, as well as a review of the possibilities of their application.

  13. Polyphenol Oxidase Enzyme and Inactivation Methods

    Directory of Open Access Journals (Sweden)

    Leman Yılmaz

    2018-03-01

    Full Text Available Polyphenol oxidase enzyme is found in vegetables and fruits, as well as in some animal organs and microorganisms. Polyphenol oxidase enzyme responsible for enzymatic browning is a group of copper proteins that catalyses the oxidation of phenolic compounds to quinones, which produce brown pigments, commonly found in fruits and vegetables. During the industrial preparation of fruits and vegetables, results of catalytic effect of polyphenol oxidase causes enzymatic browning. Enzymatic browning impairs the appearance of products containing phenolic compounds along with undesirable colour, odor and taste formation and significant loss of nutritional value of the products. This affects the acceptability of the products by the consumers and causes economic losses. In this review, some characteristics of polyphenol oxidase enzyme in different fruits and vegetables have been reviewed and information about chemical antibrowning agents, thermal applications, irradiation applications and alternative methods such as high pressure processing, pulse electric field, supercritical carbon dioxide and ultrasound applications to inactivate this enzyme has been presented.

  14. Glicerólise de óleo de peixe catalisada por lipase comercial de Rhizomucor miehei em meio com surfactante de grau alimentício Glycerolysis of fish oil catalyzed by a commercial lipase from Rhizomucor miehei in reaction media containing food grade surfactant

    Directory of Open Access Journals (Sweden)

    Joanna Silva Santos

    2013-01-01

    Full Text Available Omega-3 enriched partial acylglycerols are beneficial for human health. The aim of this study was to obtain monoacylglycerols (MAG and diacylglycerols (DAG by means of glycerolysis of fish oil catalyzed by a lipase from Rhizomucor miehei in the presence of food grade surfactants (Tween 65, 80 or 85. Glycerolysis was successful in the reaction media for all the tested surfactants, showing their potential for use as additives in such a system. The best results, however, were obtained for the reaction medium in the absence of surfactant whose peroxide value was the lowest after glycerolysis.

  15. 21 CFR 184.1063 - Enzyme-modified lecithin.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Enzyme-modified lecithin. 184.1063 Section 184.1063... Listing of Specific Substances Affirmed as GRAS § 184.1063 Enzyme-modified lecithin. (a) Enzyme-modified lecithin is prepared by treating lecithin with either phospholipase A2 (EC 3.1.1.4) or pancreatin. (b) The...

  16. Immobilized enzyme reactor chromatography: Optimization of protein retention and enzyme activity in monolithic silica stationary phases

    International Nuclear Information System (INIS)

    Besanger, Travis R.; Hodgson, Richard J.; Green, James R.A.; Brennan, John D.

    2006-01-01

    Our group recently reported on the application of protein-doped monolithic silica columns for immobilized enzyme reactor chromatography, which allowed screening of enzyme inhibitors present in mixtures using mass spectrometry for detection. The enzyme was immobilized by entrapment within a bimodal meso/macroporous silica material prepared by a biocompatible sol-gel processing route. While such columns proved to be useful for applications such as screening of protein-ligand interactions, significant amounts of entrapped proteins leached from the columns owing to the high proportion of macropores within the materials. Herein, we describe a detailed study of factors affecting the morphology of protein-doped bioaffinity columns and demonstrate that specific pH values and concentrations of poly(ethylene glycol) can be used to prepare essentially mesoporous columns that retain over 80% of initially loaded enzyme in an active and accessible form and yet still retain sufficient porosity to allow pressure-driven flow in the low μL/min range. Using the enzyme γ-glutamyl transpeptidase (γ-GT), we further evaluated the catalytic constants of the enzyme entrapped in capillary columns with different silica morphologies as a function of flowrate and backpressure using the enzyme reactor assay mode. It was found that the apparent activity of the enzyme was highest in mesoporous columns that retained high levels of enzyme. In such columns, enzyme activity increased by ∼2-fold with increases in both flowrate (from 250 to 1000 nL/min) and backpressure generated (from 500 to 2100 psi) during the chromatographic activity assay owing to increases in k cat and decreases in K M , switching from diffusion controlled to reaction controlled conditions at ca. 2000 psi. These results suggest that columns with minimal macropore volumes (<5%) are advantageous for the entrapment of soluble proteins for bioaffinity and bioreactor chromatography

  17. Artificial Enzymes, "Chemzymes"

    DEFF Research Database (Denmark)

    Bjerre, Jeannette; Rousseau, Cyril Andre Raphaël; Pedersen, Lavinia Georgeta M

    2008-01-01

    Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models that successf......Enzymes have fascinated scientists since their discovery and, over some decades, one aim in organic chemistry has been the creation of molecules that mimic the active sites of enzymes and promote catalysis. Nevertheless, even today, there are relatively few examples of enzyme models...... that successfully perform Michaelis-Menten catalysis under enzymatic conditions (i.e., aqueous medium, neutral pH, ambient temperature) and for those that do, very high rate accelerations are seldomly seen. This review will provide a brief summary of the recent developments in artificial enzymes, so called...... "Chemzymes", based on cyclodextrins and other molecules. Only the chemzymes that have shown enzyme-like activity that has been quantified by different methods will be mentioned. This review will summarize the work done in the field of artificial glycosidases, oxidases, epoxidases, and esterases, as well...

  18. Targeted enzyme prodrug therapies.

    Science.gov (United States)

    Schellmann, N; Deckert, P M; Bachran, D; Fuchs, H; Bachran, C

    2010-09-01

    The cure of cancer is still a formidable challenge in medical science. Long-known modalities including surgery, chemotherapy and radiotherapy are successful in a number of cases; however, invasive, metastasized and inaccessible tumors still pose an unresolved and ongoing problem. Targeted therapies designed to locate, detect and specifically kill tumor cells have been developed in the past three decades as an alternative to treat troublesome cancers. Most of these therapies are either based on antibody-dependent cellular cytotoxicity, targeted delivery of cytotoxic drugs or tumor site-specific activation of prodrugs. The latter is a two-step procedure. In the first step, a selected enzyme is accumulated in the tumor by guiding the enzyme or its gene to the neoplastic cells. In the second step, a harmless prodrug is applied and specifically converted by this enzyme into a cytotoxic drug only at the tumor site. A number of targeting systems, enzymes and prodrugs were investigated and improved since the concept was first envisioned in 1974. This review presents a concise overview on the history and latest developments in targeted therapies for cancer treatment. We cover the relevant technologies such as antibody-directed enzyme prodrug therapy (ADEPT), gene-directed enzyme prodrug therapy (GDEPT) as well as related therapies such as clostridial- (CDEPT) and polymer-directed enzyme prodrug therapy (PDEPT) with emphasis on prodrug-converting enzymes, prodrugs and drugs.

  19. 21 CFR 184.1287 - Enzyme-modified fats.

    Science.gov (United States)

    2010-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... that are generally recognized as safe (GRAS). Enzyme-modified milk powder may be prepared with GRAS enzymes from reconstituted milk powder, whole milk, condensed or concentrated whole milk, evaporated milk...

  20. Preparation of anti-Sudan red monoclonal antibody and development of an indirect competitive enzyme-linked immunosorbent assay for detection of Sudan red in chilli jam and chilli oil.

    Science.gov (United States)

    Xu, Jing; Zhang, Yuanyang; Yi, Jian; Meng, Meng; Wan, Yuping; Feng, Caiwei; Wang, Shanliang; Lu, Xiao; Xi, Rimo

    2010-10-01

    Sudan dyes are banned to be used in food additives because of the carcinogenicity of their metabolites. A rapid and sensitive indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect the residues of Sudan dyes. Novel immunogen and coating antigen were synthesized via glutaraldehyde linking. The hapten-bovine serum albumin (BSA) was applied as immunogen and the hapten-ovalbumin (OVA) was served as coating antigen. The monoclonal antibody obtained showed high sensitivity to Sudan I with an IC(50) value of 1.7 μg L(-1) in buffer and was suitable to detect the residues of Sudan red in food products. The specificity of the assay was studied by measuring cross-reactivity of the antibody with the structurally related compounds of Sudan II (red (120%). Chilli jam and chilli oil samples spiked with Sudan dyes were analyzed by the method. The detection limit (LOD) of the ELISA method applied in chilli jam and chilli oil was 9.0 μg L(-1) and 19.6 μg L(-1), respectively. The recovery rates of Sudan-I in chilli oil and chilli jam were in the range of 80%-110% with coefficients of variation <25%. The intra-assay variation and inter-assay variation in buffer were both <9%.

  1. Preparation and configurational analysis of the stereoisomers of β,γ-bidentate Rh(H2O)4ATP and α,β,γ-tridentate Rh(H2O)3ATP. A new class of enzyme active site probes

    International Nuclear Information System (INIS)

    Lu, Z.; Shorter, A.L.; Lin, I.; Dunaway-Mariano, D.

    1988-01-01

    Exchange-inert Co(III) and Cr(III) complexes of polyphosphates have proved to be useful probes of the structural and biochemical properties of naturally occurring Mg II (polyphosphate) complexes. However, applications of these complexes are not without limitations. The Cr III (polyphosphate) probes or their enzymatic products cannot be used in NMR methods because of the paramagnetic nature of the Cr(III) metal. The redox properties of the metal in the Co III (polyphosphate) complexes require that they also be coordinated to a nitrogen-containing ligand. This requirement is not always convenient. This work reported herein was undertaken to create a new class of exchange-inert metal polyphosphate complexes that contain a metal that is both diamagnetic and redox stable. The preparation, properties, and configurational analysis of the stereoisomers of β, γ-bidentate Rh(H 2 O) 4 ATP (ATP = adenosine 5'-triphosphate) and α,β,γ-tridentate Rh(H 2 O) 3 ATP are described. 12 refs., 5 figs

  2. 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).

  3. Indicators: Sediment Enzymes

    Science.gov (United States)

    Sediment enzymes are proteins that are produced by microorganisms living in the sediment or soil. They are indicators of key ecosystem processes and can help determine which nutrients are affecting the biological community of a waterbody.

  4. Enzyme Vs. Extremozyme -32 ...

    Indian Academy of Sciences (India)

    Enzymes are biocatalytic protein molecules that enhance the rates of ... to physical forces (hydrogen bonds, hydrophobic 1, electrostatic and Van der ... conformation. In 1995 ... surface against 14.7% in Klenow poll (some of the hydrophobic.

  5. Overproduction of ligninolytic enzymes

    Science.gov (United States)

    Elisashvili, Vladimir; Kachlishvili, Eva; Torok, Tamas

    2014-06-17

    Methods, compositions, and systems for overproducing ligninolytic enzymes from the basidiomycetous fungus are described herein. As described, the method can include incubating a fungal strain of Cerrena unicolor IBB 303 in a fermentation system having growth medium which includes lignocellulosic material and then cultivating the fungal strain in the fermentation system under conditions wherein the fungus expresses the ligninolytic enzymes. In some cases, the lignocellulosic material is mandarin peel, ethanol production residue, walnut pericarp, wheat bran, wheat straw, or banana peel.

  6. Measurement of enzyme activity.

    Science.gov (United States)

    Harris, T K; Keshwani, M M

    2009-01-01

    To study and understand the nature of living cells, scientists have continually employed traditional biochemical techniques aimed to fractionate and characterize a designated network of macromolecular components required to carry out a particular cellular function. At the most rudimentary level, cellular functions ultimately entail rapid chemical transformations that otherwise would not occur in the physiological environment of the cell. The term enzyme is used to singularly designate a macromolecular gene product that specifically and greatly enhances the rate of a chemical transformation. Purification and characterization of individual and collective groups of enzymes has been and will remain essential toward advancement of the molecular biological sciences; and developing and utilizing enzyme reaction assays is central to this mission. First, basic kinetic principles are described for understanding chemical reaction rates and the catalytic effects of enzymes on such rates. Then, a number of methods are described for measuring enzyme-catalyzed reaction rates, which mainly differ with regard to techniques used to detect and quantify concentration changes of given reactants or products. Finally, short commentary is given toward formulation of reaction mixtures used to measure enzyme activity. Whereas a comprehensive treatment of enzymatic reaction assays is not within the scope of this chapter, the very core principles that are presented should enable new researchers to better understand the logic and utility of any given enzymatic assay that becomes of interest.

  7. 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.

  8. Nanoarmored Enzymes for Organic Enzymology: Synthesis and Characterization of Poly(2-Alkyloxazoline)-Enzyme Conjugates.

    Science.gov (United States)

    Leurs, Melanie; Tiller, Joerg C

    2017-01-01

    The properties of enzymes can be altered significantly by modification with polymers. Numerous different methods are known to obtain such polymer-enzyme conjugates (PECs). However, there is no universal method to render enzymes into PECs that are fully soluble in organic solvents. Here, we present a method, which achieves such high degree of modification of proteins that the majority of modified enzymes will be soluble in organic solvents. This is achieved by preparing poly(2-alkyloxazoline)s (POx) with an NH 2 end group and coupling this functional polymer via pyromellitic acid dianhydride onto the amino groups of the respective protein. The resulting PECs are capable of serving as surfactants for unmodified proteins, rendering the whole mixture organosoluble. Depending on the nature of the POx and the molecular weight and the nature of the enzyme, the PECs are soluble in chloroform or even toluene. Another advantage of this method is that the poly(2-alkyloxazoline) can be activated with the coupling agent and used for the enzyme conjugation without further purification. The POx-enzyme conjugates generated by this modification strategy show modulated catalytic activity in both, aqueous and organic, systems. © 2017 Elsevier Inc. All rights reserved.

  9. Random-walk enzymes

    Science.gov (United States)

    Mak, Chi H.; Pham, Phuong; Afif, Samir A.; Goodman, Myron F.

    2015-09-01

    Enzymes that rely on random walk to search for substrate targets in a heterogeneously dispersed medium can leave behind complex spatial profiles of their catalyzed conversions. The catalytic signatures of these random-walk enzymes are the result of two coupled stochastic processes: scanning and catalysis. Here we develop analytical models to understand the conversion profiles produced by these enzymes, comparing an intrusive model, in which scanning and catalysis are tightly coupled, against a loosely coupled passive model. Diagrammatic theory and path-integral solutions of these models revealed clearly distinct predictions. Comparison to experimental data from catalyzed deaminations deposited on single-stranded DNA by the enzyme activation-induced deoxycytidine deaminase (AID) demonstrates that catalysis and diffusion are strongly intertwined, where the chemical conversions give rise to new stochastic trajectories that were absent if the substrate DNA was homogeneous. The C →U deamination profiles in both analytical predictions and experiments exhibit a strong contextual dependence, where the conversion rate of each target site is strongly contingent on the identities of other surrounding targets, with the intrusive model showing an excellent fit to the data. These methods can be applied to deduce sequence-dependent catalytic signatures of other DNA modification enzymes, with potential applications to cancer, gene regulation, and epigenetics.

  10. Laccase Enzymes in Inocula Pleurotus spp

    Directory of Open Access Journals (Sweden)

    Nora García-Oduardo

    2017-01-01

    Full Text Available The cultivation of edible and medicinal mushrooms Pleurotus has been aimed at promoting alternative management for agricultural products. This basidiomicete has been the subject of numerous studies because of its fruiting body constitutes a food, being a producer of enzymes with industrial interest and for its ability of biotransformation of lignocellulosic substrates. Pleurotus inocula in the established technology for growing edible and medicinal mushrooms in the CEBI Research- Production Plant were performed using sorghum or wheat. However, it is possible to expand the possibilities with other substrates. In this paper, the results of laccase enzymes production in inocula prepared with sorghum, corn and coffee pulp with two strains Pleurotus ostreatus CCEBI 3021 and Pleurotus ostreatus CCEBI 3024 are presented. The period of preparation of seed reaches 15-21 days, the measurements of laccase activity were performed in periods of seven days. Extraction of crude enzyme was performed in aqueous phase, the determination of the laccase enzyme activity, using guaiacol as substrate. The results obtained in this work with studies in previous work using sorghum as inocula are compared. It is found that higher yields are obtained laccase in coffee pulp. This study contributes to the theoretical knowledge and to provide alternatives for securing the production process of the plant.

  11. Matrix Metalloproteinase Enzyme Family

    Directory of Open Access Journals (Sweden)

    Ozlem Goruroglu Ozturk

    2013-04-01

    Full Text Available Matrix metalloproteinases play an important role in many biological processes such as embriogenesis, tissue remodeling, wound healing, and angiogenesis, and in some pathological conditions such as atherosclerosis, arthritis and cancer. Currently, 24 genes have been identified in humans that encode different groups of matrix metalloproteinase enzymes. This review discuss the members of the matrix metalloproteinase family and their substrate specificity, structure, function and the regulation of their enzyme activity by tissue inhibitors. [Archives Medical Review Journal 2013; 22(2.000: 209-220

  12. Isolation and removal of proteolytic enzymes with magnetic cross-linked erythrocytes

    International Nuclear Information System (INIS)

    Safarik, I. Ivo; Safarikova, Mirka

    2001-01-01

    New magnetic adsorbents for batch isolation and removal of various proteolytic enzymes were prepared by glutaraldehyde cross-linking of bovine, porcine and human erythrocytes in the presence of fine magnetic particles. Trypsin, chymotrypsin, alkaline bacterial protease and proteases present in various commercial enzyme preparations were efficiently adsorbed on these adsorbents; on the contrary, proteins without proteolytic activity were not adsorbed

  13. The surface science of enzymes

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Nørskov, Jens Kehlet

    2002-01-01

    One of the largest challenges to science in the coming years is to find the relation between enzyme structure and function. Can we predict which reactions an enzyme catalyzes from knowledge of its structure-or from its amino acid sequence? Can we use that knowledge to modify enzyme function......? To solve these problems we must understand in some detail how enzymes interact with reactants from its surroundings. These interactions take place at the surface of the enzyme and the question of enzyme function can be viewed as the surface science of enzymes. In this article we discuss how to describe...... catalysis by enzymes, and in particular the analogies between enzyme catalyzed reactions and surface catalyzed reactions. We do this by discussing two concrete examples of reactions catalyzed both in nature (by enzymes) and in industrial reactors (by inorganic materials), and show that although analogies...

  14. Magnetically responsive enzyme powders

    Czech Academy of Sciences Publication Activity Database

    Pospišková, K.; Šafařík, Ivo

    2015-01-01

    Roč. 380, APR 2015 (2015), s. 197-200 ISSN 0304-8853 R&D Projects: GA MŠk(CZ) LD13021 Institutional support: RVO:67179843 Keywords : enzyme powders * cross-linking * magnetic modification * magnetic separation * magnetic iron oxides particles * microwave-assisted synthesis Subject RIV: CE - Biochemistry Impact factor: 2.357, year: 2015

  15. Enzyme with rhamnogalacturonase activity.

    NARCIS (Netherlands)

    Kofod, L.V.; Andersen, L.N.; Dalboge, H.; Kauppinen, M.S.; Christgau, S.; Heldt-Hansen, H.P.; Christophersen, C.; Nielsen, P.M.; Voragen, A.G.J.; Schols, H.A.

    1998-01-01

    An enzyme exhibiting rhamnogalacturonase activity, capable of cleaving a rhamnogalacturonan backbone in such a manner that galacturonic acids are left as the non-reducing ends, and which exhibits activity on hairy regions from a soy bean material and/or on saponified hairy regions from a sugar beet

  16. Implantable enzyme amperometric biosensors.

    Science.gov (United States)

    Kotanen, Christian N; Moussy, Francis Gabriel; Carrara, Sandro; Guiseppi-Elie, Anthony

    2012-05-15

    The implantable enzyme amperometric biosensor continues as the dominant in vivo format for the detection, monitoring and reporting of biochemical analytes related to a wide range of pathologies. Widely used in animal studies, there is increasing emphasis on their use in diabetes care and management, the management of trauma-associated hemorrhage and in critical care monitoring by intensivists in the ICU. These frontier opportunities demand continuous indwelling performance for up to several years, well in excess of the currently approved seven days. This review outlines the many challenges to successful deployment of chronically implantable amperometric enzyme biosensors and emphasizes the emerging technological approaches in their continued development. The foreign body response plays a prominent role in implantable biotransducer failure. Topics considering the approaches to mitigate the inflammatory response, use of biomimetic chemistries, nanostructured topographies, drug eluting constructs, and tissue-to-device interface modulus matching are reviewed. Similarly, factors that influence biotransducer performance such as enzyme stability, substrate interference, mediator selection and calibration are reviewed. For the biosensor system, the opportunities and challenges of integration, guided by footprint requirements, the limitations of mixed signal electronics, and power requirements, has produced three systems approaches. The potential is great. However, integration along the multiple length scales needed to address fundamental issues and integration across the diverse disciplines needed to achieve success of these highly integrated systems, continues to be a challenge in the development and deployment of implantable amperometric enzyme biosensor systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Advances in enzyme bioelectrochemistry

    Directory of Open Access Journals (Sweden)

    ANDRESSA R. PEREIRA

    Full Text Available ABSTRACT Bioelectrochemistry can be defined as a branch of Chemical Science concerned with electron-proton transfer and transport involving biomolecules, as well as electrode reactions of redox enzymes. The bioelectrochemical reactions and system have direct impact in biotechnological development, in medical devices designing, in the behavior of DNA-protein complexes, in green-energy and bioenergy concepts, and make it possible an understanding of metabolism of all living organisms (e.g. humans where biomolecules are integral to health and proper functioning. In the last years, many researchers have dedicated itself to study different redox enzymes by using electrochemistry, aiming to understand their mechanisms and to develop promising bioanodes and biocathodes for biofuel cells as well as to develop biosensors and implantable bioelectronics devices. Inside this scope, this review try to introduce and contemplate some relevant topics for enzyme bioelectrochemistry, such as the immobilization of the enzymes at electrode surfaces, the electron transfer, the bioelectrocatalysis, and new techniques conjugated with electrochemistry vising understand the kinetics and thermodynamics of redox proteins. Furthermore, examples of recent approaches in designing biosensors and biofuel developed are presented.

  18. Cold-Adapted Enzymes

    Science.gov (United States)

    Georlette, D.; Bentahir, M.; Claverie, P.; Collins, T.; D'amico, S.; Delille, D.; Feller, G.; Gratia, E.; Hoyoux, A.; Lonhienne, T.; Meuwis, M.-a.; Zecchinon, L.; Gerday, Ch.

    In the last few years, increased attention has been focused on enzymes produced by cold-adapted micro-organisms. It has emerged that psychrophilic enzymes represent an extremely powerful tool in both protein folding investigations and for biotechnological purposes. Such enzymes are characterised by an increased thermosensitivity and, most of them, by a higher catalytic efficiency at low and moderate temperatures, when compared to their mesophilic counterparts. The high thermosensitivity probably originates from an increased flexibility of either a selected area of the molecular edifice or the overall protein structure, providing enhanced abilities to undergo conformational changes during catalysis at low temperatures. Structure modelling and recent crystallographic data have allowed to elucidate the structural parameters that could be involved in this higher resilience. It was demonstrated that each psychrophilic enzyme adopts its own adaptive strategy. It appears, moreover, that there is a continuum in the strategy of protein adaptation to temperature, as the previously mentioned structural parameters are implicated in the stability of thermophilic proteins. Additional 3D crystal structures, site-directed and random mutagenesis experiments should now be undertaken to further investigate the stability-flexibility-activity relationship.

  19. Embedded enzymes catalyse capture

    Science.gov (United States)

    Kentish, Sandra

    2018-05-01

    Membrane technologies for carbon capture can offer economic and environmental advantages over conventional amine-based absorption, but can suffer from limited gas flux and selectivity to CO2. Now, a membrane based on enzymes embedded in hydrophilic pores is shown to exhibit combined flux and selectivity that challenges the state of the art.

  20. Photoperiodism and Enzyme Activity

    Science.gov (United States)

    Queiroz, Orlando; Morel, Claudine

    1974-01-01

    Metabolic readjustments after a change from long days to short days appear, in Kalanchoe blossfeldiana, to be achieved through the operation of two main mechanisms: variation in enzyme capacity, and circadian rhythmicity. After a lag time, capacity in phosphoenolpyruvate carboxylase and capacity in aspartate aminotransferase increase exponentially and appear to be allometrically linked during 50 to 60 short days; then a sudden fall takes place in the activity of the former. Malic enzyme and alanine aminotransferase behave differently. Thus, the operation of the two sections of the pathway (before and after the malate step) give rise to a continuously changing functional compartmentation in the pathway. Circadian rhythmicity, on the other hand, produces time compartmentation through phase shifts and variation in amplitude, independently for each enzyme. These characteristics suggest that the operation of a so-called biological clock would be involved. We propose the hypothesis that feedback regulation would be more accurate and efficient when applied to an already oscillating, clock-controlled enzyme system. PMID:16658749

  1. ISFET based enzyme sensors

    NARCIS (Netherlands)

    van der Schoot, Bart H.; Bergveld, Piet

    1987-01-01

    This paper reviews the results that have been reported on ISFET based enzyme sensors. The most important improvement that results from the application of ISFETs instead of glass membrane electrodes is in the method of fabrication. Problems with regard to the pH dependence of the response and the

  2. [Research on the preparative method of Arctigenin].

    Science.gov (United States)

    Zhang, Li-Ying; Yang, Yi-Shun; Zhang, Tong; Ding, Yue; Cai, Zhen-Zhen; Tao, Jian-Sheng

    2012-03-01

    To research on the preparation of Arctigenin in vitro. Took enzyme concentration, time course and substrate concentration as investigation factors, used Box-Behnken design-response surface methodology to optimize the enzyme hydrolysis path of Arctigenin. The best operational path for Arctigenin was as follows: the temperature was 50 degrees C, pH was 4.8, enzyme concentration was 0.44 U/mL, time course was 46.81 min, substrate concentration was 0.29 mg/mL, the conversion rate was 90.94%. This research can be regarded as a referencein preparing Arctigenin in vitro.

  3. Anti-ulcer, anti-protozoan and anti-cancer activities of irradiated κ-carrageenan: some biological effects of irradiated food grade-carrageenan on various gastrointestinal disorders

    International Nuclear Information System (INIS)

    Deocaris, Custer C.; Cruz, Angela C; Dela Rosa, Alumanda M.; De Guzman, Roche Ray C.; Abilo, Rhea Mae L.; Gutierrez, Ana Kamila O.; Deocaris, Chester C.

    2001-01-01

    κ carrageenan and its radiolytic products are both shown to strongly inhibit pepsin activity based on our in vitro peptic ulcer model. Generated Lineweaver-Burke (LB) plots resemble the trend for competitive inhibition except that the changes in the slopes are too large rendering Km to approach a negative value. Our observations corroborate with the published dual behavior of carrageenan in inhibiting peptic ulcers, that is, by exerting simultaneously both enzyme (E) competitive inhibition and substrate (S) occlusion. Irradiated-carrageenan does not display anti-protozoan activity against Tetrahymena and pathogenic Entamoeba histolytica, and anti-tumor potential based on Artemia salina (brine shrimp) nauplus tests and the MTT assay with human MCF7 breast carcinoma cell line. (Author)

  4. Hydrolytic enzymes production by Aspergillus section Nigri in presence of butylated hydroxyanisole and propyl paraben on peanut meal extract agar.

    Science.gov (United States)

    Barberis, Carla L; Landa, María F; Barberis, Mauricio G; Giaj-Merlera, Guillermo; Dalcero, Ana M; Magnoli, Carina E

    2014-01-01

    In the last years, food grade antioxidants are used safely as an alternative to traditional fungicides to control fungal growth in several food and agricultural products. In this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (β-d-glucosidase and α-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (aW; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96h) was evaluated on peanut-based medium. The activity of two glycosidases, β-d-glucosidase and α-d-galactosidase, was assayed using as substrates 4-nitrophenyl-β-d-glucopyranosido and 4-nitrophenyl-α-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute. The major inhibition in β-d-glucosidase activity of A. carbonarius and A. niger was found with 20mmoll(-1) of BHA or PP at 0.98 and 0.95 aW, respectively, whereas for α-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20mmoll(-1) of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20mmoll(-1) of BHA or PP at 0.95 aW and 96h. The results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species. Copyright © 2012 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  5. The Enzyme Function Initiative†

    Science.gov (United States)

    Gerlt, John A.; Allen, Karen N.; Almo, Steven C.; Armstrong, Richard N.; Babbitt, Patricia C.; Cronan, John E.; Dunaway-Mariano, Debra; Imker, Heidi J.; Jacobson, Matthew P.; Minor, Wladek; Poulter, C. Dale; Raushel, Frank M.; Sali, Andrej; Shoichet, Brian K.; Sweedler, Jonathan V.

    2011-01-01

    The Enzyme Function Initiative (EFI) was recently established to address the challenge of assigning reliable functions to enzymes discovered in bacterial genome projects; in this Current Topic we review the structure and operations of the EFI. The EFI includes the Superfamily/Genome, Protein, Structure, Computation, and Data/Dissemination Cores that provide the infrastructure for reliably predicting the in vitro functions of unknown enzymes. The initial targets for functional assignment are selected from five functionally diverse superfamilies (amidohydrolase, enolase, glutathione transferase, haloalkanoic acid dehalogenase, and isoprenoid synthase), with five superfamily-specific Bridging Projects experimentally testing the predicted in vitro enzymatic activities. The EFI also includes the Microbiology Core that evaluates the in vivo context of in vitro enzymatic functions and confirms the functional predictions of the EFI. The deliverables of the EFI to the scientific community include: 1) development of a large-scale, multidisciplinary sequence/structure-based strategy for functional assignment of unknown enzymes discovered in genome projects (target selection, protein production, structure determination, computation, experimental enzymology, microbiology, and structure-based annotation); 2) dissemination of the strategy to the community via publications, collaborations, workshops, and symposia; 3) computational and bioinformatic tools for using the strategy; 4) provision of experimental protocols and/or reagents for enzyme production and characterization; and 5) dissemination of data via the EFI’s website, enzymefunction.org. The realization of multidisciplinary strategies for functional assignment will begin to define the full metabolic diversity that exists in nature and will impact basic biochemical and evolutionary understanding, as well as a wide range of applications of central importance to industrial, medicinal and pharmaceutical efforts. PMID

  6. The Enzyme Function Initiative.

    Science.gov (United States)

    Gerlt, John A; Allen, Karen N; Almo, Steven C; Armstrong, Richard N; Babbitt, Patricia C; Cronan, John E; Dunaway-Mariano, Debra; Imker, Heidi J; Jacobson, Matthew P; Minor, Wladek; Poulter, C Dale; Raushel, Frank M; Sali, Andrej; Shoichet, Brian K; Sweedler, Jonathan V

    2011-11-22

    The Enzyme Function Initiative (EFI) was recently established to address the challenge of assigning reliable functions to enzymes discovered in bacterial genome projects; in this Current Topic, we review the structure and operations of the EFI. The EFI includes the Superfamily/Genome, Protein, Structure, Computation, and Data/Dissemination Cores that provide the infrastructure for reliably predicting the in vitro functions of unknown enzymes. The initial targets for functional assignment are selected from five functionally diverse superfamilies (amidohydrolase, enolase, glutathione transferase, haloalkanoic acid dehalogenase, and isoprenoid synthase), with five superfamily specific Bridging Projects experimentally testing the predicted in vitro enzymatic activities. The EFI also includes the Microbiology Core that evaluates the in vivo context of in vitro enzymatic functions and confirms the functional predictions of the EFI. The deliverables of the EFI to the scientific community include (1) development of a large-scale, multidisciplinary sequence/structure-based strategy for functional assignment of unknown enzymes discovered in genome projects (target selection, protein production, structure determination, computation, experimental enzymology, microbiology, and structure-based annotation), (2) dissemination of the strategy to the community via publications, collaborations, workshops, and symposia, (3) computational and bioinformatic tools for using the strategy, (4) provision of experimental protocols and/or reagents for enzyme production and characterization, and (5) dissemination of data via the EFI's Website, http://enzymefunction.org. The realization of multidisciplinary strategies for functional assignment will begin to define the full metabolic diversity that exists in nature and will impact basic biochemical and evolutionary understanding, as well as a wide range of applications of central importance to industrial, medicinal, and pharmaceutical efforts.

  7. Studies on the preparation of immobilized enzymes by radiopolymerization, (9)

    International Nuclear Information System (INIS)

    Kawashima, Koji; Fujino, Satomi; Hayashi, Toru; Kim, Sung-K.

    1982-01-01

    Glucose Oxidase (GOD, EC 1, 1, 3, 4) was immobilized in the form of the beads by the radiation polymerization method under low temperature and the enzymatic characteristics were investigated. 1) Polyethyleneglycol dimethacrylate and acrylamide were favorable compounds for the immobilization of GOD. 2) Neither optimum pH nor pH stability was changed after immobilization treatment. 3) Optimum reaction temperature was shifted by 5 0 C to the higher side and heat stability was improved. 4) Immobilized GOD showed activity up to 60U per gram of dried polymer. 5) The small beads had retained high activities (10 - 80%) 6) The immobilized GOD was not leached out from the polymer matrix. (author)

  8. Current IUBMB recommendations on enzyme nomenclature and kinetics

    Directory of Open Access Journals (Sweden)

    Athel Cornish-Bowden

    2014-05-01

    Full Text Available The International Union of Biochemistry (IUB, now IUBMB prepared recommendations for describing the kinetic behaviour of enzymes in 1981. Despite the more than 30 years that have passed since these have not subsequently been revised, though in various respects they do not adequately cover current needs. The IUBMB is also responsible for recommendations on the naming and classification of enzymes. In contrast to the case of kinetics, these recommendations are kept continuously up to date.

  9. Determining the safety of enzymes used in animal feed.

    Science.gov (United States)

    Pariza, Michael W; Cook, Mark

    2010-04-01

    The purpose of this paper is to provide guidance for evaluating the safety of enzyme preparations used in animal feed. Feed enzymes are typically added to animal feed to increase nutrient bioavailability by acting on feed components prior to or after consumption, i.e., within the gastrointestinal tract. In contrast, food processing enzymes are generally used during processing and then inactivated or removed prior to consumption. The enzymes used in both applications are almost always impure mixtures of active enzyme and other metabolites from the production strain, hence similar safety evaluation procedures for both are warranted. We propose that the primary consideration should be the safety of the production strain and that the decision tree mechanism developed previously for food processing enzymes (Pariza and Johnson, 2001) is appropriate for determining the safety of feed enzymes. Thoroughly characterized non-pathogenic, non-toxigenic microbial strains with a history of safe use in enzyme manufacture are also logical candidates for generating safe strain lineages, from which additional strains may be derived via genetic modification by traditional and non-traditional strategies. For new feed enzyme products derived from a safe strain lineage, it is important to ensure a sufficiently high safety margin for the intended use, and that the product complies with appropriate specifications for chemical and microbial contamination. Copyright 2009 Elsevier Inc. All rights reserved.

  10. Synthesis and Characterization of Magnetic Carriers Based on Immobilized Enzyme

    Science.gov (United States)

    Li, F. H.; Tang, N.; Wang, Y. Q.; Zhang, L.; Du, W.; Xiang, J.; Cheng, P. G.

    2018-05-01

    Several new types of carriers and technologies have been implemented to improve traditional enzyme immobilization in industrial biotechnology. The magnetic immobilized enzyme is a kind of new method of enzyme immobilization developed in recent years. An external magnetic field can be used to control the motion mode and direction of immobilized enzyme, and to improve the catalytic efficiency of immobilized enzyme. In this paper, Fe3O4-CaCO3-PDA complex and CaCO3/Fe3O4 composite modified by PEI were prepared. The results show that the morphology of Fe3O4-CaCO3-PDA complex formation is irregular, while the morphology of CaCO3/Fe3O4 composite modified by PEI is regular and has a porous structure.

  11. NRSA enzyme decomposition model data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Microbial enzyme activities measured at more than 2000 US streams and rivers. These enzyme data were then used to predict organic matter decomposition and microbial...

  12. Cellulase enzyme and biomass utilization

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-03

    Jun 3, 2009 ... human population grows and economic development. However, the current .... conditions and the production cost of the related enzyme system. Therefore ... Given the importance of this enzyme to these so many industries,.

  13. Personnel Preparation.

    Science.gov (United States)

    Fair, George, Ed.; Stodden, Robert, Ed.

    1981-01-01

    Three articles comprise a section on personnel preparation in vocational education. Articles deal with two inservice programs in career/vocational education for the handicapped and a project to train paraprofessionals to assist special educators in vocational education. (CL)

  14. Solution preparation

    International Nuclear Information System (INIS)

    Seitz, M.G.

    1982-01-01

    Reviewed in this statement are methods of preparing solutions to be used in laboratory experiments to examine technical issues related to the safe disposal of nuclear waste from power generation. Each approach currently used to prepare solutions has advantages and any one approach may be preferred over the others in particular situations, depending upon the goals of the experimental program. These advantages are highlighted herein for three approaches to solution preparation that are currently used most in studies of nuclear waste disposal. Discussion of the disadvantages of each approach is presented to help a user select a preparation method for his particular studies. Also presented in this statement are general observations regarding solution preparation. These observations are used as examples of the types of concerns that need to be addressed regarding solution preparation. As shown by these examples, prior to experimentation or chemical analyses, laboratory techniques based on scientific knowledge of solutions can be applied to solutions, often resulting in great improvement in the usefulness of results

  15. Performance of hemicellulolytic enzymes in culture supernatants from a wide range of fungi on insoluble wheat straw and corn fiber fractions

    NARCIS (Netherlands)

    Gool, van M.P.; Toth, K.; Schols, H.A.; Szakacs, G.; Gruppen, H.

    2012-01-01

    Filamentous fungi are a good source of hemicellulolytic enzymes for biomass degradation. Enzyme preparations were obtained as culture supernatants from 78 fungal isolates grown on wheat straw as carbon source. These enzyme preparations were utilized in the hydrolysis of insoluble wheat straw and

  16. Enzyme recycling in lignocellulosic biorefineries

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Pinelo, Manuel

    2017-01-01

    platform. Cellulases are the most important enzymes required in this process, but the complex nature of lignocellulose requires several other enzymes (hemicellulases and auxiliary enzymes) for efficient hydrolysis. Enzyme recycling increases the catalytic productivity of the enzymes by reusing them...... for several batches of hydrolysis, and thereby reduces the overall cost associated with the hydrolysis. Research on this subject has been ongoing for many years and several promising technologies and methods have been developed and demonstrated. But only in a very few cases have these technologies been...... upscaled and tested in industrial settings, mainly because of many difficulties with recycling of enzymes from the complex lignocellulose hydrolyzate at industrially relevant conditions, i.e., high solids loadings. The challenges are associated with the large number of different enzymes required...

  17. Characterising Complex Enzyme Reaction Data.

    Directory of Open Access Journals (Sweden)

    Handan Melike Dönertaş

    Full Text Available The relationship between enzyme-catalysed reactions and the Enzyme Commission (EC number, the widely accepted classification scheme used to characterise enzyme activity, is complex and with the rapid increase in our knowledge of the reactions catalysed by enzymes needs revisiting. We present a manual and computational analysis to investigate this complexity and found that almost one-third of all known EC numbers are linked to more than one reaction in the secondary reaction databases (e.g., KEGG. Although this complexity is often resolved by defining generic, alternative and partial reactions, we have also found individual EC numbers with more than one reaction catalysing different types of bond changes. This analysis adds a new dimension to our understanding of enzyme function and might be useful for the accurate annotation of the function of enzymes and to study the changes in enzyme function during evolution.

  18. Recent advances in enzyme extraction strategies: A comprehensive review.

    Science.gov (United States)

    Nadar, Shamraja S; Pawar, Rohini G; Rathod, Virendra K

    2017-08-01

    The increasing interest of industrial enzymes demands for development of new downstream strategies for maximizing enzyme recovery. The significant efforts have been focused on the development of newly adapted technologies to purify enzymes in catalytically active form. Recently, an aqueous two phase system (ATPS) is emerged as powerful tools for efficient extraction and purification of enzymes due to their versatility, lower cost, process integration capability and easy scale-up. The present review gives an overview of effect of parameters such as tie line length, pH, neutral salts, properties of polymer and salt involved in traditional polymer/polymer and polymer/salt ATPS for enzyme recovery. Further, advanced ATPS have been developed based on alcohols, surfactants, micellar compounds to avoid tedious recovery steps for getting desired enzyme. In order to improve the selectivity and efficiency of ATPS, recent approaches of conventional ATPS combined with different techniques like affinity ligands, ionic liquids, thermoseparating polymers and microfluidic device based ATPS have been reviewed. Moreover, three phase partitioning is also highlighted for enzymes enrichment as a blooming technology for efficiently integrated bioseparation techniques. At the end, it includes an overview of CLEAs technology and organic-inorganic nanoflowers preparation as novel strategies for simultaneous extraction, purification and immobilization of enzymes. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Measuring the Enzyme Activity of Arabidopsis Deubiquitylating Enzymes.

    Science.gov (United States)

    Kalinowska, Kamila; Nagel, Marie-Kristin; Isono, Erika

    2016-01-01

    Deubiquitylating enzymes, or DUBs, are important regulators of ubiquitin homeostasis and substrate stability, though the molecular mechanisms of most of the DUBs in plants are not yet understood. As different ubiquitin chain types are implicated in different biological pathways, it is important to analyze the enzyme characteristic for studying a DUB. Quantitative analysis of DUB activity is also important to determine enzyme kinetics and the influence of DUB binding proteins on the enzyme activity. Here, we show methods to analyze DUB activity using immunodetection, Coomassie Brilliant Blue staining, and fluorescence measurement that can be useful for understanding the basic characteristic of DUBs.

  20. In vitro tissue-digesting properties of krill enzymes compared with fibrinolysin/DNAse, papain and placebo

    NARCIS (Netherlands)

    Mekkes, J. R.; Le Poole, I. C.; Das, P. K.; Kammeyer, A.; Westerhof, W.

    1997-01-01

    Wound debridement, the removal of necrotic tissue, can be achieved with proteolytic enzymes. Recently, a new multi-enzyme preparation, krill enzyme, isolated from Antarctic shrimp-like organisms (Euphausia superba), was reported to possess powerful proteolytic activity towards protein substrates. In

  1. Sample preparation

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Sample preparation prior to HPLC analysis is certainly one of the most important steps to consider in trace or ultratrace analysis. For many years scientists have tried to simplify the sample preparation process. It is rarely possible to inject a neat liquid sample or a sample where preparation may not be any more complex than dissolution of the sample in a given solvent. The last process alone can remove insoluble materials, which is especially helpful with the samples in complex matrices if other interactions do not affect extraction. Here, it is very likely a large number of components will not dissolve and are, therefore, eliminated by a simple filtration process. In most cases, the process of sample preparation is not as simple as dissolution of the component interest. At times, enrichment is necessary, that is, the component of interest is present in very large volume or mass of material. It needs to be concentrated in some manner so a small volume of the concentrated or enriched sample can be injected into HPLC. 88 refs

  2. Stimulation of Escherichia coli DNA photoreactivating enzyme activity by adenosine 5'-triphosphate

    International Nuclear Information System (INIS)

    Koka, P.

    1984-01-01

    A purification procedure consisting of Biorex-70, single-stranded DNA-agarose, and ultraviolet (UV) light irradiated DNA-cellulose chromatography has been adopted for the Escherichia coli photoreactivating enzyme, to obtain enzyme preparations that are free of extraneous nucleic acid or nucleotides. The purification yields high specific activities (75 000 pmol h -1 mg -1 ) with a 50% recovery. Enzyme preparations have also been obtained from UV-irradiated DNA-cellulose by exposure to visible light. These enzyme preparations contain oligoribonucleotides, up to 26 nucleotides in length in relation to DNA size markers, but these are not essential for enzymatic activity. When the enzyme is preincubated with exogenous ATP a 10-fold stimulation in the enzyme activity has been observed. It has been determined by polyacrylamide gel electrophoresis and high-voltage diethylaminoethyl paper electrophoresis that the light-released enzyme samples from a preincubated and washed mixture of the enzyme, [γ- 32 P]ATP, and UV-irradiated DNA-cellulose contained exogenous [γ- 32 P], which eluted with the enzyme-containing fractions when subjected to Bio-Gel P-30 chromatography. GTP caused a slight enhancement of the enzyme activity while ADP strongly inhibited photoreactivation, at the same concentration and conditions. Higher (X5) concentrations of ADP and adenosine 5'-(β, γ-methylenetriphosphate) totally inhibited the enzyme activity. Dialysis of a photoreactivating enzyme preparation against a buffer solution containing 1 mM ATP caused a 9-fold stimulation of the enzyme activity. In addition, there is an apparent hydrolysis of ATP during photoreactivation as measured by the release of 32 P from [γ- 32 P]ATP

  3. Enzyme Molecules in Solitary Confinement

    Directory of Open Access Journals (Sweden)

    Raphaela B. Liebherr

    2014-09-01

    Full Text Available Large arrays of homogeneous microwells each defining a femtoliter volume are a versatile platform for monitoring the substrate turnover of many individual enzyme molecules in parallel. The high degree of parallelization enables the analysis of a statistically representative enzyme population. Enclosing individual enzyme molecules in microwells does not require any surface immobilization step and enables the kinetic investigation of enzymes free in solution. This review describes various microwell array formats and explores their applications for the detection and investigation of single enzyme molecules. The development of new fabrication techniques and sensitive detection methods drives the field of single molecule enzymology. Here, we introduce recent progress in single enzyme molecule analysis in microwell arrays and discuss the challenges and opportunities.

  4. DGAT enzymes and triacylglycerol biosynthesis

    Science.gov (United States)

    Yen, Chi-Liang Eric; Stone, Scot J.; Koliwad, Suneil; Harris, Charles; Farese, Robert V.

    2008-01-01

    Triacylglycerols (triglycerides) (TGs) are the major storage molecules of metabolic energy and FAs in most living organisms. Excessive accumulation of TGs, however, is associated with human diseases, such as obesity, diabetes mellitus, and steatohepatitis. The final and the only committed step in the biosynthesis of TGs is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. The genes encoding two DGAT enzymes, DGAT1 and DGAT2, were identified in the past decade, and the use of molecular tools, including mice deficient in either enzyme, has shed light on their functions. Although DGAT enzymes are involved in TG synthesis, they have distinct protein sequences and differ in their biochemical, cellular, and physiological functions. Both enzymes may be useful as therapeutic targets for diseases. Here we review the current knowledge of DGAT enzymes, focusing on new advances since the cloning of their genes, including possible roles in human health and diseases. PMID:18757836

  5. Reproductive performance of female goats fed life-enzyme ...

    African Journals Online (AJOL)

    Direct-fed-microbes (DFM) (life-enzyme) was prepared in a traditional setting using Zymomonas mobilis (bacteria from palm sap) to ferment sawdust. The result revealed an improvement in the nutrient content of the sawdust and its feed values (protein, fibre etc.), and the feed usage efficiency. The reproductive ...

  6. Direct comparison of enzyme histochemical and immunohistochemical methods to localize an enzyme

    NARCIS (Netherlands)

    van Noorden, Cornelis J. F.

    2002-01-01

    Immunohistochemical localization of enzymes is compared directly with localization of enzyme activity with (catalytic) enzyme histochemical methods. The two approaches demonstrate principally different aspects of an enzyme. The immunohistochemical method localizes the enzyme protein whether it is

  7. Phage lytic enzymes: a history.

    Science.gov (United States)

    Trudil, David

    2015-02-01

    There are many recent studies regarding the efficacy of bacteriophage-related lytic enzymes: the enzymes of 'bacteria-eaters' or viruses that infect bacteria. By degrading the cell wall of the targeted bacteria, these lytic enzymes have been shown to efficiently lyse Gram-positive bacteria without affecting normal flora and non-related bacteria. Recent studies have suggested approaches for lysing Gram-negative bacteria as well (Briersa Y, et al., 2014). These enzymes include: phage-lysozyme, endolysin, lysozyme, lysin, phage lysin, phage lytic enzymes, phageassociated enzymes, enzybiotics, muralysin, muramidase, virolysin and designations such as Ply, PAE and others. Bacteriophages are viruses that kill bacteria, do not contribute to antimicrobial resistance, are easy to develop, inexpensive to manufacture and safe for humans, animals and the environment. The current focus on lytic enzymes has been on their use as anti-infectives in humans and more recently in agricultural research models. The initial translational application of lytic enzymes, however, was not associated with treating or preventing a specific disease but rather as an extraction method to be incorporated in a rapid bacterial detection assay (Bernstein D, 1997).The current review traces the translational history of phage lytic enzymes-from their initial discovery in 1986 for the rapid detection of group A streptococcus in clinical specimens to evolving applications in the detection and prevention of disease in humans and in agriculture.

  8. Enzyme-Gelatin Electrochemical Biosensors: Scaling Down

    Directory of Open Access Journals (Sweden)

    Hendrik A. Heering

    2012-03-01

    Full Text Available In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

  9. Research Applications of Proteolytic Enzymes in Molecular Biology

    Directory of Open Access Journals (Sweden)

    József Tőzsér

    2013-11-01

    Full Text Available Proteolytic enzymes (also termed peptidases, proteases and proteinases are capable of hydrolyzing peptide bonds in proteins. They can be found in all living organisms, from viruses to animals and humans. Proteolytic enzymes have great medical and pharmaceutical importance due to their key role in biological processes and in the life-cycle of many pathogens. Proteases are extensively applied enzymes in several sectors of industry and biotechnology, furthermore, numerous research applications require their use, including production of Klenow fragments, peptide synthesis, digestion of unwanted proteins during nucleic acid purification, cell culturing and tissue dissociation, preparation of recombinant antibody fragments for research, diagnostics and therapy, exploration of the structure-function relationships by structural studies, removal of affinity tags from fusion proteins in recombinant protein techniques, peptide sequencing and proteolytic digestion of proteins in proteomics. The aim of this paper is to review the molecular biological aspects of proteolytic enzymes and summarize their applications in the life sciences.

  10. Enzyme structure, enzyme function and allozyme diversity in ...

    African Journals Online (AJOL)

    In estimates of population genetic diversity based on allozyme heterozygosity, some enzymes are regularly more variable than others. Evolutionary theory suggests that functionally less important molecules, or parts of molecules, evolve more rapidly than more important ones; the latter enzymes should then theoretically be ...

  11. Computational enzyme design: transitioning from catalytic proteins to enzymes.

    Science.gov (United States)

    Mak, Wai Shun; Siegel, Justin B

    2014-08-01

    The widespread interest in enzymes stem from their ability to catalyze chemical reactions under mild and ecologically friendly conditions with unparalleled catalytic proficiencies. While thousands of naturally occurring enzymes have been identified and characterized, there are still numerous important applications for which there are no biological catalysts capable of performing the desired chemical transformation. In order to engineer enzymes for which there is no natural starting point, efforts using a combination of quantum chemistry and force-field based protein molecular modeling have led to the design of novel proteins capable of catalyzing chemical reactions not catalyzed by naturally occurring enzymes. Here we discuss the current status and potential avenues to pursue as the field of computational enzyme design moves forward. Published by Elsevier Ltd.

  12. Immobilized enzymes: understanding enzyme - surface interactions at the molecular level.

    Science.gov (United States)

    Hoarau, Marie; Badieyan, Somayesadat; Marsh, E Neil G

    2017-11-22

    Enzymes immobilized on solid supports have important and industrial and medical applications. However, their uses are limited by the significant reductions in activity and stability that often accompany the immobilization process. Here we review recent advances in our understanding of the molecular level interactions between proteins and supporting surfaces that contribute to changes in stability and activity. This understanding has been facilitated by the application of various surface-sensitive spectroscopic techniques that allow the structure and orientation of enzymes at the solid/liquid interface to be probed, often with monolayer sensitivity. An appreciation of the molecular interactions between enzyme and surface support has allowed the surface chemistry and method of enzyme attachement to be fine-tuned such that activity and stability can be greatly enhanced. These advances suggest that a much wider variety of enzymes may eventually be amenable to immobilization as green catalysts.

  13. Stability of Enzymes in Granular Enzyme Products for Laundry Detergents

    DEFF Research Database (Denmark)

    Biran, Suzan; Bach, Poul; Simonsen, Ole

    Enzymes have long been of interest to the detergent industry due to their ability to improve the cleaning efficiency of synthetic detergents, contribute to shortening washing times, and reduce energy and water consumption, provision of environmentally friendlier wash water effluents and fabric care....... However, incorporating enzymes in detergent formulations gives rise to numerous practical problems due to their incompatibility with and stability against various detergent components. In powdered detergent formulations, these issues can be partly overcome by physically isolating the enzymes in separate...... particles. However, enzymes may loose a significant part of their activity over a time period of several weeks. Possible causes of inactivation of enzymes in a granule may be related to the release of hydrogen peroxide from the bleaching chemicals in a moisture-containing atmosphere, humidity, autolysis...

  14. Enzymes in Human Milk.

    Science.gov (United States)

    Dallas, David C; German, J Bruce

    2017-01-01

    Milk proteins are a complex and diverse source of biological activities. Beyond their function, intact milk proteins also act as carriers of encrypted functional sequences that, when released as peptides, exert biological functions, including antimicrobial and immunomodulatory activity, which could contribute to the infant's competitive success. Research has now revealed that the release of these functional peptides begins within the mammary gland itself. A complex array of proteases produced in mother's milk has been shown to be active in the milk, releasing these peptides. Moreover, our recent research demonstrates that these milk proteases continue to digest milk proteins within the infant's stomach, possibly even to a larger extent than the infant's own proteases. As the neonate has relatively low digestive capacity, the activity of milk proteases in the infant may provide important assistance to digesting milk proteins. The coordinated release of these encrypted sequences is accomplished by selective proteolytic action provided by an array of native milk proteases and infant-produced enzymes. The task for scientists is now to discover the selective advantages of this protein-protease-based peptide release system. © 2017 Nestec Ltd., Vevey/S. Karger AG, Basel.

  15. Effects of dietary supplementation of multi-enzyme complex on the ...

    African Journals Online (AJOL)

    Jane

    2011-07-25

    Jul 25, 2011 ... and protein escape digestion, reach the midgut and undergo fermentation ... soybean broiler starter diet with an enzyme preparation containing a mixture .... due to the rapid food rate and the deficiency of the necessary innate ...

  16. 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.

  17. Digestive enzymes of some earthworms.

    Science.gov (United States)

    Mishra, P C; Dash, M C

    1980-10-15

    4 species of tropical earthworms differed with regard to enzyme activity. The maximum activity of protease and of cellulase occurred in the posterior region of the gut of the earthworms. On the average Octochaetona surensis shows maximum activity and Drawida calebi shows minimum activity for all the enzymes studied.

  18. Selective distribution of enzymes in a microfluidic reactor

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Pereira Rosinha Grundtvig, Ines; Krühne, Ulrich

    Off stoichiometric thiol-ene mixtures are well suited for preparation of microfluidic devices with highly functional surfaces. Here a two stage process employing first thiol-ene chemistry (TEC) to prepare two opposite parts of a microfluidic system with a 30x30 mm reactor and subsequently a thiol......-epoxy bonding was used to prepare a fully sealed microfluidic system. The reactor was surface functionalized in-situ with allyl glycidyl ether in different patterns (half-reactor, full-reactor, checkerboard structures) on the surface to provide a controlled distribution of epoxides. The method additionally...... enables the selective immobilization on either top-side or bottom-side or both sides of the reactor. Thereafter horseradish peroxidase was immobilized on the surface and activity tests illustrated how this distribution of the enzyme on the surface could be used to optimize the activity of the enzyme...

  19. Bioethanol production by inherent enzymes from rye and wheat with addition of organic farming cheese whey

    DEFF Research Database (Denmark)

    Kádár, Zsófia; Christensen, Anne Deen; Thomsen, Mette Hedegaard

    2011-01-01

    . Throughout our studies, wheat and rye grain was used as raw material in bioethanol production with the purpose of producing in situ enzymes (during germination) for the hydrolysis of starch in the grains and compared with commercial amylase enzyme preparations. Whey permeate was incorporated into the grain...

  20. Inhibitors of the bacterial cell wall biosynthesis enzyme MurC.

    Science.gov (United States)

    Reck, F; Marmor, S; Fisher, S; Wuonola, M A

    2001-06-04

    A series of phosphinate transition-state analogues of the L-alanine adding enzyme (MurC) of bacterial peptidoglycan biosynthesis was prepared and tested as inhibitors of the Escherichia coli enzyme. Compound 4 was identified as a potent inhibitor of MurC from Escherichia coli with an IC(50) of 49nM.

  1. Enzymes extracted from apple peels have activity in reducing higher alcohols in Chinese liquors.

    Science.gov (United States)

    Han, Qi'an; Shi, Junling; Zhu, Jing; Lv, Hongliang; Du, Shuangkui

    2014-10-01

    As the unavoidable byproducts of alcoholic fermentation, higher alcohols are unhealthy compounds widespread in alcoholic drinks. To investigate the activity of apple crude enzymes toward higher alcohols in liquors, five kinds of apple peels, namely, Fuji, Gala, Golden Delicious, Red Star, and Jonagold, were chosen to prepare enzymes, and three kinds of Chinese liquors, namely, Xifeng (containing 45% ethanol), Taibai (containing 50% ethanol), and Erguotou (containing 56% ethanol), were tested. Enzymes were prepared in the forms of liquid solution, powder, and immobilized enzymes using sodium alginate (SA) and chitosan. The treatment was carried out at 37 °C for 1 h. The relative amounts of different alcohols (including ethanol, 1-propanol, isobutanol, 1-butanol, isoamylol, and 1-hexanol) were measured using gas chromatography (GC). Conditions for preparing SA-immobilized Fuji enzymes (SA-IEP) were optimized, and the obtained SA-IEP (containing 0.3 g of enzyme) was continuously used to treat Xifeng liquor eight times, 20 mL per time. Significant degradation rates (DRs) of higher alcohols were observed at different degrees, and it also showed enzyme specificity according to the apple varieties and enzyme preparations. After five repeated treatments, the DRs of the optimized Fuji SA-IEP remained 70% for 1-hexanol and >15% for other higher alcohols.

  2. Evaluation of the effects of enzyme-based liquid chemical stabilizers on subgrade soils

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2009-07-01

    Full Text Available The purpose of this study was to asses the strength of enzyme treated soil material. Thus the aim of the paper is to present laboratory results on the effects of two enzyme-based liquid chemicals as soil stabilizers. Soil samples were prepared...

  3. Photoreactivating enzyme from Escherichia coli

    International Nuclear Information System (INIS)

    Snapka, R.M.; Fuselier, C.O.

    1977-01-01

    Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm. (author)

  4. Positron emitter labeled enzyme inhibitors

    International Nuclear Information System (INIS)

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-01-01

    This invention involves a new strategy for imagining and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography

  5. Photoreactivating enzyme from Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Snapka, R M; Fuselier, C O [California Univ., Irvine (USA)

    1977-05-01

    Escherichia coli photoreactivating enzyme (PRE) has been purified in large amounts from an E.coli strain lysogenic for a defective lambda bacteriophage carrying the phr gene. The resulting enzyme had a pH optimum of 7.2 and an ionic strength optimum of 0.18. It consisted of an apoprotein and cofactor, both of which were necessary for catalytic activity. The apoprotein had a monomer molecular weight of 35,200 and showed stable aggregates under denaturing conditions. The amino acid analysis of the E.coli enzyme was very similar to that of the photoreactivating enzyme from orchid seedlings (Cattelya aurantiaca). Both had arginine at the amino terminus. The cofactor, like the holoenzyme, showed absorption, magnetic circular dichroism, and emission properties indicative of an adenine moiety. Although the isolated enzyme had an action spectrum which peaked at about 360 nm, neither the cofactor, apoenzyme nor holoenzyme showed any detectable absorption between 300 and 400 nm.

  6. Radioprotective preparation

    International Nuclear Information System (INIS)

    Stefanova, D.; Frattadochi, A.; Gattavecchia, E.; Ferri, E.; Tonnelli, D.

    1988-01-01

    The invention is intended for radiation injuries prophylaxis in mammals. It has an well expressed radioprotective effect against acute gamma irradiation on cellular level as well as a prolonged action when applied up to 48 hours before the acute irradiation. The preparation is a coprecipitate of the natural tripeptide glutathione (reduced form) and polyvinyl pyrrolidone (pvp) in ratio 30-60/70-40. It is obtained by incubation method with subsequent lyophilization from water solution of the initial components. The molecular mass of the pvp is 20 till 360.10 3 . 2 claims

  7. Target preparation

    International Nuclear Information System (INIS)

    Hinn, G.M.

    1984-01-01

    A few of the more interesting of the 210 targets prepared in the Laboratory last year are listed. In addition the author continues to use powdered silver mixed with /sup 9,10/BeO to produce sources for accelerator radio dating of Alaskan and South Polar snow. Currently, he is trying to increase production by multiple sample processing. Also the author routinely makes 3 μg/cm 2 cracked slacked carbon stripper foils and is continuing research with some degree of success in making enriched 28 Si targets starting with the oxide

  8. Trichoderma longibrachiatum acetyl xylan esterase 1 enhances hemicellulolytic preparations to degrade corn silage polysaccharides

    NARCIS (Netherlands)

    Neumüller, K.G.; Streekstra, H.; Gruppen, H.; Schols, H.A.

    2014-01-01

    Supplementation of a Trichoderma longibrachiatum preparation to an industrial Aspergillus niger/Talaromyces emersonii enzyme mixture demonstrated synergy for the saccharification of corn silage water-unextractable solids (WUS). Sub-fractions of the crude T. longibrachiatum preparation obtained after

  9. Phospholipid-sepiolite biomimetic interfaces for the immobilization of enzymes.

    Science.gov (United States)

    Wicklein, Bernd; Darder, Margarita; Aranda, Pilar; Ruiz-Hitzky, Eduardo

    2011-11-01

    Biomimetic interfaces based on phosphatidylcholine (PC) assembled to the natural silicate sepiolite were prepared for the stable immobilization of the urease and cholesterol oxidase enzymes. This is an important issue in practical advanced applications such as biocatalysis or biosensing. The supported lipid bilayer (BL-PC), prepared from PC adsorption, was used for immobilization of enzymes and the resulting biomimetic systems were compared to several other supported layers including a lipid monolayer (ML-PC), a mixed phosphatidylcholine/octyl-galactoside layer (PC-OGal), a cetyltrimethylammonium monolayer (CTA), and also to the bare sepiolite surface. Interfacial characteristics of these layers were investigated with a focus on layer packing density, hydrophilicity/hydrophobicity, and surface charge, which are being considered as key points for enzyme immobilization and stabilization of their biological activity. Cytoplasmic urease and membrane-bound cholesterol oxidase, which served as model enzymes, were immobilized on the different PC-based hybrid materials to probe their biomimetic character. Enzymatic activity was assessed by cyclic voltammetry and UV-vis spectrophotometry. The resulting enzyme/bio-organoclay hybrids were applied as active phase of a voltammetric urea biosensor and cholesterol bioreactor, respectively. Urease supported on sepiolite/BL-PC proved to maintain its enzymatic activity over several months while immobilized cholesterol oxidase demonstrated high reusability as biocatalyst. The results emphasize the good preservation of bioactivity due to the accommodation of the enzymatic system within the biomimetic lipid interface on sepiolite.

  10. Preparation and characterization of two types of covalently immobilized amyloglucosidase

    Directory of Open Access Journals (Sweden)

    ZORAN VUJCIC

    2005-05-01

    Full Text Available Amyloglucosidase from A. niger was covalently immobilized onto poly (GMA-co-EGDMA by the glutaraldehyde and periodate method. The immobilization of amyloglucosidase after periodate oxidation gave a preparate with the highest specific activity reported so far on similar polymers. The obtained immobilized preparates show the same pH optimum, but a higher temperature optimum compared with the soluble enzyme. The kinetic parameters for the hydrolysis of soluble starch by free and both immobilized enzymes were determined.

  11. BAKERY ENZYMES IN CEREAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    Václav Koman

    2012-10-01

    Full Text Available Normal 0 21 false false false SK X-NONE X-NONE Bread is the most common and traditional food in the world. For years, enzymes such as malt and fungal alpha-amylase have been used in bread making. Due to the changes in the baking industry and the ever-increasing demand for more natural products, enzymes have gained real importance in bread-making. If an enzyme is added, it is often destroyed by the heat during the baking process. For generations, enzymes have been used for the improvement of texture and appearance, enhancement of nutritional values and generation of appealing flavours and aromas. Enzymes used in bakery industry constitute nearly one third of the market. The bakery products have undergone radical improvements in quality over the past years in terms of flavour, texture and shelf-life. The the biggest contributor for these improvementsis the usage of enzymes. Present work seeks to systematically describe bakery enzymes, their classification, benefits, usage and chemical reactions in the bread making process.doi:10.5219/193

  12. Counter current extraction of phosphoric acid: Food grade acid production

    International Nuclear Information System (INIS)

    Shlewit, H.; AlIbrahim, M.

    2009-01-01

    Extraction, scrubbing and stripping of phosphoric acid from the Syrian wet-phosphoric acid was carried out using Micro-pilot plant of mixer settler type of 8 l/h capacity. Tributyl phosphate (TBP)/di-isopropyl ether (DIPE) in kerosene was used as extractant. Extraction and stripping equilibrium curves were evaluated. The number of extraction and stripping stages to achieve the convenient and feasible yield was determined. Detailed flow sheet was suggested for the proposed continuous process. Data obtained include useful information for the design of phosphoric acid extraction plant. The produced phosphoric acid was characterized using different analytical techniques. (author)

  13. EFFECT OF SODIUM PHOSPHATES ON SELECTED FOOD GRADE BACTERIA

    Directory of Open Access Journals (Sweden)

    Stanislav Kráčmar

    2011-04-01

    Full Text Available The aim of this study was to examine the inhibitory effect in vitro of selected sodium phosphates (under the corporate names Hexa 68, Hexa 70, Trikrystal, FST, Pyro 52, KPS, Didi on selected gram-positive and gram-negative bacteria. Seven different concentrations of each phosphate were used. Sensitivity of the bacterial strains to phosphates was observed in broth supplemented with salts. In vitro was showed a negative effect of various phosphates on growth of selected gram-positive bacteria. Orthophosphates and diphosphates (pyrophosphates did not have significant inhibitory effect on tested bacteria at neutral pH. With the exception of phosphate Trikrystal has not been found in vitro significant inhibitory effects on gram-negative bacteria.doi:10.5219/141

  14. Reprint of "food-grade electrospinning of proteins"

    NARCIS (Netherlands)

    Nieuwland, M.; Geerdink, P.; Brier, P.; Eijnden, P. van den; Henket, J.T.M.M.; Langelaan, M.L.P.; Stroeks, N.; Deventer, H.C. van; Martin, A.H.

    2014-01-01

    Developing non-meat food products with an appealing structure is a challenge. In this study, we investigate the possibility to produce thin fibrils as building blocks for texturally interesting meat replacers. The technique applied is electrospinning - a technique which produces thin fibrils with a

  15. [Automated analyzer of enzyme immunoassay].

    Science.gov (United States)

    Osawa, S

    1995-09-01

    Automated analyzers for enzyme immunoassay can be classified by several points of view: the kind of labeled antibodies or enzymes, detection methods, the number of tests per unit time, analytical time and speed per run. In practice, it is important for us consider the several points such as detection limits, the number of tests per unit time, analytical range, and precision. Most of the automated analyzers on the market can randomly access and measure samples. I will describe the recent advance of automated analyzers reviewing their labeling antibodies and enzymes, the detection methods, the number of test per unit time and analytical time and speed per test.

  16. Enzyme stabilization by glass-derived silicates in glass-exposed aqueous solutions

    Science.gov (United States)

    Ives, J.A.; Moffett, J.R.; Arun, P.; Lam, D.; Todorov, T.I.; Brothers, A.B.; Anick, D.J.; Centeno, J.; Namboodiri, M.A.A.; Jonas, W.B.

    2010-01-01

    Objectives: To analyze the solutes leaching from glass containers into aqueous solutions, and to show that these solutes have enzyme activity stabilizing effects in very dilute solutions. Methods: Enzyme assays with acetylcholine esterase were used to analyze serially succussed and diluted (SSD) solutions prepared in glass and plastic containers. Aqueous SSD preparations starting with various solutes, or water alone, were prepared under several conditions, and tested for their solute content and their ability to affect enzyme stability in dilute solution. Results: We confirm that water acts to dissolve constituents from glass vials, and show that the solutes derived from the glass have effects on enzymes in the resultant solutions. Enzyme assays demonstrated that enzyme stability in purified and deionized water was enhanced in SSD solutions that were prepared in glass containers, but not those prepared in plastic. The increased enzyme stability could be mimicked in a dose-dependent manner by the addition of silicates to the purified, deionized water that enzymes were dissolved in. Elemental analyses of SSD water preparations made in glass vials showed that boron, silicon, and sodium were present at micromolar concentrations. Conclusions: These results show that silicates and other solutes are present at micromolar levels in all glass-exposed solutions, whether pharmaceutical or homeopathic in nature. Even though silicates are known to have biological activity at higher concentrations, the silicate concentrations we measured in homeopathic preparations were too low to account for any purported in vivo efficacy, but could potentially influence in vitro biological assays reporting homeopathic effects. ?? 2009 The Faculty of Homeopathy.

  17. Studies of the immobilization of enzymes and microorganism pt.1

    International Nuclear Information System (INIS)

    Kim, S.K.

    1979-01-01

    A new method of immobilization of glucose oxidase by the aerobic gamma radiation of synthetic monomers was developed. The radiocopolymerization was conducted aerobically at -70 to-80 degC with the mixture of several polyfunctional esters, acrylates and native enzyme. The retained activity of immobilized glucoseoxidase was about 50 to 55% when a NK 23G ester, acrylamide-bis and water mixture (1:1:2) in cold toluene treated with 450 Krad of gamma radiation. The radiation dose did not influence significantly to the enzyme activity. The solvents used to prepare the beads of glucose oxidase and monomers were toluene, n-hexane, petoleum ether and chloroform. 0.05M tris-gycerol(pH 7.0) was a more suitable buffer solution for immobilizing the enzyme than was 0.02M phosphate. Immobilization of glucose oxidase shifted the optimum pH for its reaction from 6.0 to 6.5. The pH profile for the immobilized enzyme showed a broad range of optimum activity while the native enzyme gave a sharp pick for its optimum pH value. The immobilized enzyme reaction temperature was at the range of 30-40 degreesC. (Author)

  18. Silica Sol-Gel Entrapment of the Enzyme Chloro peroxidase

    International Nuclear Information System (INIS)

    Le, T.; Chan, S.; Ebaid, B.; Sommerhalter, M.

    2015-01-01

    The enzyme chloro peroxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (∼3 nm) was smaller than the globular CPO diameter (∼6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9-12% relative activity compared to free CPO in solution. Enzyme kinetic analysis revealed a decrease in K_cat but no changes in K_M or K_I . Product release or enzyme damage might thus limit catalytic performance. Yet circular dichroism and visible absorption spectra of transparent CPO sol-gel sheets did not indicate enzyme damage. Activity decline due to methanol exposure was shown to be reversible in solution. To improve catalytic performance the sol-gel protocol was modified. The incorporation of 5, 20, or 40% methyltrimethoxysilane resulted in more brittle sol-gel beads but the catalytic performance increased to 14% relative to free CPO in solution. The use of more acidic casting buffers (ph 4.5 or 5.5 instead of 6.5) resulted in a more porous silica host reaching up to 18% relative activity

  19. Multi-enzyme Process Modeling

    DEFF Research Database (Denmark)

    Andrade Santacoloma, Paloma de Gracia

    are affected (in a positive or negative way) by the presence of the other enzymes and compounds in the media. In this thesis the concept of multi-enzyme in-pot term is adopted for processes that are carried out by the combination of enzymes in a single reactor and implemented at pilot or industrial scale...... features of the process and provides the information required to structure the process model by using a step-by-step procedure with the required tools and methods. In this way, this framework increases efficiency of the model development process with respect to time and resources needed (fast and effective....... In this way the model parameters that drives the main dynamic behavior can be identified and thus a better understanding of this type of processes. In order to develop, test and verify the methodology, three case studies were selected, specifically the bi-enzyme process for the production of lactobionic acid...

  20. PIXE analysis of Zn enzymes

    International Nuclear Information System (INIS)

    Solis, C.; Oliver, A.; Andrade, E.; Ruvalcaba-Sil, J.L.; Romero, I.; Celis, H.

    1999-01-01

    Zinc is a necessary component in the action and structural stability of many enzymes. Some of them are well characterized, but in others, Zn stoichiometry and its association is not known. PIXE has been proven to be a suitable technique for analyzing metallic proteins embedded in electrophoresis gels. In this study, PIXE has been used to investigate the Zn content of enzymes that are known to carry Zn atoms. These include the carbonic anhydrase, an enzyme well characterized by other methods and the cytoplasmic pyrophosphatase of Rhodospirillum rubrum that is known to require Zn to be stable but not how many metal ions are involved or how they are bound to the enzyme. Native proteins have been purified by polyacrylamide gel electrophoresis and direct identification and quantification of Zn in the gel bands was performed with an external proton beam of 3.7 MeV energy

  1. GRE Enzymes for Vector Analysis

    Data.gov (United States)

    U.S. Environmental Protection Agency — Microbial enzyme data that were collected during the 2004-2006 EMAP-GRE program. These data were then used by Moorhead et al (2016) in their ecoenzyme vector...

  2. Watching Individual Enzymes at Work

    Science.gov (United States)

    Blank, Kerstin; Rocha, Susana; De Cremer, Gert; Roeffaers, Maarten B. J.; Uji-i, Hiroshi; Hofkens, Johan

    Single-molecule fluorescence experiments are a powerful tool to analyze reaction mechanisms of enzymes. Because of their unique potential to detect heterogeneities in space and time, they have provided unprecedented insights into the nature and mechanisms of conformational changes related to the catalytic reaction. The most important finding from experiments with single enzymes is the generally observed phenomenon that the catalytic rate constants fluctuate over time (dynamic disorder). These fluctuations originate from conformational changes occurring on time scales, which are similar to or slower than that of the catalytic reaction. Here, we summarize experiments with enzymes that show dynamic disorder and introduce new experimental strategies showing how single-molecule fluorescence experiments can be applied to address other open questions in medical and industrial enzymology, such as enzyme inactivation processes, reactant transfer in cascade reactions, and the mechanisms of interfacial catalysis.

  3. Photosynthetic fuel for heterologous enzymes

    DEFF Research Database (Denmark)

    Mellor, Silas Busck; Vavitsas, Konstantinos; Nielsen, Agnieszka Janina Zygadlo

    2017-01-01

    of reducing power. Recent work on the metabolic engineering of photosynthetic organisms has shown that the electron carriers such as ferredoxin and flavodoxin can be used to couple heterologous enzymes to photosynthetic reducing power. Because these proteins have a plethora of interaction partners and rely...... on electrostatically steered complex formation, they form productive electron transfer complexes with non-native enzymes. A handful of examples demonstrate channeling of photosynthetic electrons to drive the activity of heterologous enzymes, and these focus mainly on hydrogenases and cytochrome P450s. However......, competition from native pathways and inefficient electron transfer rates present major obstacles, which limit the productivity of heterologous reactions coupled to photosynthesis. We discuss specific approaches to address these bottlenecks and ensure high productivity of such enzymes in a photosynthetic...

  4. Co-immobilization of multiple enzymes by metal coordinated nucleotide hydrogel nanofibers: improved stability and an enzyme cascade for glucose detection.

    Science.gov (United States)

    Liang, Hao; Jiang, Shuhui; Yuan, Qipeng; Li, Guofeng; Wang, Feng; Zhang, Zijie; Liu, Juewen

    2016-03-21

    Preserving enzyme activity and promoting synergistic activity via co-localization of multiple enzymes are key topics in bionanotechnology, materials science, and analytical chemistry. This study reports a facile method for co-immobilizing multiple enzymes in metal coordinated hydrogel nanofibers. Specifically, four types of protein enzymes, including glucose oxidase, Candida rugosa lipase, α-amylase, and horseradish peroxidase, were respectively encapsulated in a gel nanofiber made of Zn(2+) and adenosine monophosphate (AMP) with a simple mixing step. Most enzymes achieved quantitative loading and retained full activity. At the same time, the entrapped enzymes were more stable against temperature variation (by 7.5 °C), protease attack, extreme pH (by 2-fold), and organic solvents. After storing for 15 days, the entrapped enzyme still retained 70% activity while the free enzyme nearly completely lost its activity. Compared to nanoparticles formed with AMP and lanthanide ions, the nanofiber gels allowed much higher enzyme activity. Finally, a highly sensitive and selective biosensor for glucose was prepared using the gel nanofiber to co-immobilize glucose oxidase and horseradish peroxidase for an enzyme cascade system. A detection limit of 0.3 μM glucose with excellent selectivity was achieved. This work indicates that metal coordinated materials using nucleotides are highly useful for interfacing with biomolecules.

  5. DGAT enzymes and triacylglycerol biosynthesis

    OpenAIRE

    Yen, Chi-Liang Eric; Stone, Scot J.; Koliwad, Suneil; Harris, Charles; Farese, Robert V.

    2008-01-01

    Triacylglycerols (triglycerides) (TGs) are the major storage molecules of metabolic energy and FAs in most living organisms. Excessive accumulation of TGs, however, is associated with human diseases, such as obesity, diabetes mellitus, and steatohepatitis. The final and the only committed step in the biosynthesis of TGs is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. The genes encoding two DGAT enzymes, DGAT1 and DGAT2, were identified in the past decade, ...

  6. Enzymes: principles and biotechnological applications

    Science.gov (United States)

    Robinson, Peter K.

    2015-01-01

    Enzymes are biological catalysts (also known as biocatalysts) that speed up biochemical reactions in living organisms, and which can be extracted from cells and then used to catalyse a wide range of commercially important processes. This chapter covers the basic principles of enzymology, such as classification, structure, kinetics and inhibition, and also provides an overview of industrial applications. In addition, techniques for the purification of enzymes are discussed. PMID:26504249

  7. de novo computational enzyme design.

    Science.gov (United States)

    Zanghellini, Alexandre

    2014-10-01

    Recent advances in systems and synthetic biology as well as metabolic engineering are poised to transform industrial biotechnology by allowing us to design cell factories for the sustainable production of valuable fuels and chemicals. To deliver on their promises, such cell factories, as much as their brick-and-mortar counterparts, will require appropriate catalysts, especially for classes of reactions that are not known to be catalyzed by enzymes in natural organisms. A recently developed methodology, de novo computational enzyme design can be used to create enzymes catalyzing novel reactions. Here we review the different classes of chemical reactions for which active protein catalysts have been designed as well as the results of detailed biochemical and structural characterization studies. We also discuss how combining de novo computational enzyme design with more traditional protein engineering techniques can alleviate the shortcomings of state-of-the-art computational design techniques and create novel enzymes with catalytic proficiencies on par with natural enzymes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Biocatalysis with thermostable enzymes: structure and properties of a thermophilic 'ene'-reductase related to old yellow enzyme.

    Science.gov (United States)

    Adalbjörnsson, Björn V; Toogood, Helen S; Fryszkowska, Anna; Pudney, Christopher R; Jowitt, Thomas A; Leys, David; Scrutton, Nigel S

    2010-01-25

    We report the crystal structure of a thermophilic "ene" reductase (TOYE) isolated from Thermoanaerobacter pseudethanolicus E39. The crystal structure reveals a tetrameric enzyme and an active site that is relatively large compared to most other structurally determined and related Old Yellow Enzymes. The enzyme adopts higher order oligomeric states (octamers and dodecamers) in solution, as revealed by sedimentation velocity and multiangle laser light scattering. Bead modelling indicates that the solution structure is consistent with the basic tetrameric structure observed in crystallographic studies and electron microscopy. TOYE is stable at high temperatures (T(m)>70 degrees C) and shows increased resistance to denaturation in water-miscible organic solvents compared to the mesophilic Old Yellow Enzyme family member, pentaerythritol tetranitrate reductase. TOYE has typical ene-reductase properties of the Old Yellow Enzyme family. There is currently major interest in using Old Yellow Enzyme family members in the preparative biocatalysis of a number of activated alkenes. The increased stability of TOYE in organic solvents is advantageous for biotransformations in which water-miscible organic solvents and biphasic reaction conditions are required to both deliver novel substrates and minimize product racemisation.

  9. Assembly and multiple gene expression of thermophilic enzymes in Escherichia coli for in vitro metabolic engineering.

    Science.gov (United States)

    Ninh, Pham Huynh; Honda, Kohsuke; Sakai, Takaaki; Okano, Kenji; Ohtake, Hisao

    2015-01-01

    In vitro reconstitution of an artificial metabolic pathway is an emerging approach for the biocatalytic production of industrial chemicals. However, several enzymes have to be separately prepared (and purified) for the construction of an in vitro metabolic pathway, thereby limiting the practical applicability of this approach. In this study, genes encoding the nine thermophilic enzymes involved in a non-ATP-forming chimeric glycolytic pathway were assembled in an artificial operon and co-expressed in a single recombinant Escherichia coli strain. Gene expression levels of the thermophilic enzymes were controlled by their sequential order in the artificial operon. The specific activities of the recombinant enzymes in the cell-free extract of the multiple-gene-expression E. coli were 5.0-1,370 times higher than those in an enzyme cocktail prepared from a mixture of single-gene-expression strains, in each of which a single one of the nine thermophilic enzymes was overproduced. Heat treatment of a crude extract of the multiple-gene-expression cells led to the denaturation of indigenous proteins and one-step preparation of an in vitro synthetic pathway comprising only a limited number of thermotolerant enzymes. Coupling this in vitro pathway with other thermophilic enzymes including the H2 O-forming NADH oxidase or the malate/lactate dehydrogenase facilitated one-pot conversion of glucose to pyruvate or lactate, respectively. © 2014 Wiley Periodicals, Inc.

  10. Engineering Cellulase Enzymes for Bioenergy

    Science.gov (United States)

    Atreya, Meera Elizabeth

    Sustainable energy sources, such as biofuels, offer increasingly important alternatives to fossil fuels that contribute less to global climate change. The energy contained within cellulosic biofuels derives from sunlight energy stored in the form of carbon-carbon bonds comprising sugars such as glucose. Second-generation biofuels are produced from lignocellulosic biomass feedstocks, including agricultural waste products and non-food crops like Miscanthus, that contain lignin and the polysaccharides hemicellulose and cellulose. Cellulose is the most abundant biological material on Earth; it is a polymer of glucose and a structural component of plant cell walls. Accessing the sugar is challenging, as the crystalline structure of cellulose resists degradation; biochemical and thermochemical means can be used to depolymerize cellulose. Cellulase enzymes catalyze the biochemical depolymerization of cellulose into glucose. Glucose can be used as a carbon source for growth of a biofuel-producing microorganism. When it converts glucose to a hydrocarbon fuel, this microbe completes the biofuels process of transforming sunlight energy into accessible, chemical energy capable of replacing non-renewable transportation fuels. Due to strong intermolecular interactions between polymer chains, cellulose is significantly more challenging to depolymerize than starch, a more accessible polymer of glucose utilized in first-generation biofuels processes (often derived from corn). While most mammals cannot digest cellulose (dietary fiber), certain fungi and bacteria produce cellulase enzymes capable of hydrolyzing it. These organisms secrete a wide variety of glycoside hydrolase and other classes of enzymes that work in concert. Because cellulase enzymes are slow-acting and expensive to produce, my aim has been to improve the properties of these enzymes as a means to make a cellulosic biofuels process possible that is more efficient and, consequently, more economical than current

  11. Determination of soluble dietary fibre content of Okara treated with high hydrostatic pressure and enzymes: a comparative evaluation of two methods (AOAC and HPLC-ELSD).

    Science.gov (United States)

    Pérez-López, E; Mateos-Aparicio, I; Rupérez, P

    2017-04-01

    Okara is a promising by-product from soybean and a rich source of dietary fibre, chiefly insoluble (IDF). To increase its solubility and functionality, a treatment with high hydrostatic pressure (HHP) assisted by food grade enzymes - Ultraflo ® L or Viscozyme ® L- has been performed. To monitor the effectiveness, an analysis of dietary fibre, mainly the soluble fraction (SDF), was accomplished by the AOAC enzymatic-gravimetric method with dialysis followed by both, spectrophotometric methods and High Performance Liquid Chromatography with Evaporative Light Scattering Detector (HPLC-ELSD) analysis of the soluble fraction. A significant increase in SDF (≈1.5-times) to the expense of a decrease in IDF was shown and chromatograms revealed two peaks of 95 and 22 kDa. Thus, treated Okara possessed a more balanced and convenient ratio of soluble to insoluble dietary fibre, which could have health benefits as prebiotic. Inbuilt interferences of the official AOAC's method for dietary fibre were confirmed and the direct HPLC-ELSD approach was about twice more sensitive than spectrophotometric methods. Consequently, the direct HPLC-ELSD analysis of the supernatant is proposed as a cheaper, faster and reliable method. Combined HHP-treatments plus specific enzymes represent a promising alternative for the valorisation and preservation of agrofood by-products.

  12. Enzymes and Enzyme Activity Encoded by Nonenveloped Viruses.

    Science.gov (United States)

    Azad, Kimi; Banerjee, Manidipa; Johnson, John E

    2017-09-29

    Viruses are obligate intracellular parasites that rely on host cell machineries for their replication and survival. Although viruses tend to make optimal use of the host cell protein repertoire, they need to encode essential enzymatic or effector functions that may not be available or accessible in the host cellular milieu. The enzymes encoded by nonenveloped viruses-a group of viruses that lack any lipid coating or envelope-play vital roles in all the stages of the viral life cycle. This review summarizes the structural, biochemical, and mechanistic information available for several classes of enzymes and autocatalytic activity encoded by nonenveloped viruses. Advances in research and development of antiviral inhibitors targeting specific viral enzymes are also highlighted.

  13. Method of preparing tritium-labelled thymidine-5'-monophosphates of high specific activity

    International Nuclear Information System (INIS)

    Filip, J.; Vesely, J.; Cihak, A.

    1976-01-01

    A method is described of preparing thymidine-5'-monophosphates labelled with tritium of high specific activity based on enzyme synthesis in vitro. Phosphorylation was carried out using the catalytic effect of an enzyme contained in the supernatant fraction prepared from Yoshida ascites carcinoma in rats. The course of the enzyme reaction can be controlled by the concentration of the individual reaction mixture components. The method described allows obtaining thymidine-5'-monophosphate of radiochemical purity better than 95%. (J.B.)

  14. Rethinking fundamentals of enzyme action.

    Science.gov (United States)

    Northrop, D B

    1999-01-01

    Despite certain limitations, investigators continue to gainfully employ concepts rooted in steady-state kinetics in efforts to draw mechanistically relevant inferences about enzyme catalysis. By reconsidering steady-state enzyme kinetic behavior, this review develops ideas that allow one to arrive at the following new definitions: (a) V/K, the ratio of the maximal initial velocity divided by the Michaelis-Menten constant, is the apparent rate constant for the capture of substrate into enzyme complexes that are destined to yield product(s) at some later point in time; (b) the maximal velocity V is the apparent rate constant for the release of substrate from captured complexes in the form of free product(s); and (c) the Michaelis-Menten constant K is the ratio of the apparent rate constants for release and capture. The physiologic significance of V/K is also explored to illuminate aspects of antibiotic resistance, the concept of "perfection" in enzyme catalysis, and catalytic proficiency. The conceptual basis of congruent thermodynamic cycles is also considered in an attempt to achieve an unambiguous way for comparing an enzyme-catalyzed reaction with its uncatalyzed reference reaction. Such efforts promise a deeper understanding of the origins of catalytic power, as it relates to stabilization of the reactant ground state, stabilization of the transition state, and reciprocal stabilizations of ground and transition states.

  15. Early-branching Gut Fungi Possess A Large, And Comprehensive Array Of Biomass-Degrading Enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Kevin V.; Haitjema, Charles; Henske, John K.; Gilmore, Sean P.; Borges-Rivera, Diego; Lipzen, Anna; Brewer, Heather M.; Purvine, Samuel O.; Wright, Aaron T.; Theodorou, Michael K.; Grigoriev, Igor V.; Regev, Aviv; Thompson, Dawn; O' Malley, Michelle A.

    2016-03-11

    The fungal kingdom is the source of almost all industrial enzymes in use for lignocellulose bioprocessing. Its more primitive members, however, remain relatively unexploited. We developed a systems-level approach that integrates RNA-Seq, proteomics, phenotype and biochemical studies of relatively unexplored early-branching free-living fungi. Anaerobic gut fungi isolated from herbivores produce a large array of biomass-degrading enzymes that synergistically degrade crude, unpretreated plant biomass, and are competitive with optimized commercial preparations from Aspergillus and Trichoderma. Compared to these model platforms, gut fungal enzymes are unbiased in substrate preference due to a wealth of xylan-degrading enzymes. These enzymes are universally catabolite repressed, and are further regulated by a rich landscape of noncoding regulatory RNAs. Furthermore, we identified several promising sequence divergent enzyme candidates for lignocellulosic bioprocessing.

  16. Subcellular localization of pituitary enzymes

    Science.gov (United States)

    Smith, R. E.

    1970-01-01

    A cytochemical procedure is reported for identifying subcellular sites of enzymes hydrolyzing beta-naphthylamine substrates, and to study the sites of reaction product localization in cells of various tissues. Investigations using the substrate Leu 4-methoxy-8-naphthylamine, a capture with hexonium pararosaniline, and the final chelation of osmium have identified the hydrolyzing enzyme of rat liver cells; this enzyme localized on cell membranes with intense deposition in the areas of the parcanaliculi. The study of cells in the anterior pituitary of the rat showed the deposition of reaction product on cell membrane; and on the membranes of secretion granules contained within the cell. The deposition of reaction product on the cell membrane however showed no increase or decrease with changes in the physiological state of the gland and release of secretion granules from specific cells.

  17. Enzymes in CO2 Capture

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Gladis, Arne; Thomsen, Kaj

    The enzyme Carbonic Anhydrase (CA) can accelerate the absorption rate of CO2 into aqueous solutions by several-fold. It exist in almost all living organisms and catalyses different important processes like CO2 transport, respiration and the acid-base balances. A new technology in the field...... of carbon capture is the application of enzymes for acceleration of typically slow ternary amines or inorganic carbonates. There is a hidden potential to revive currently infeasible amines which have an interesting low energy consumption for regeneration but too slow kinetics for viable CO2 capture. The aim...... of this work is to discuss the measurements of kinetic properties for CA promoted CO2 capture solvent systems. The development of a rate-based model for enzymes will be discussed showing the principles of implementation and the results on using a well-known ternary amine for CO2 capture. Conclusions...

  18. Biomolecular hybrid material and process for preparing same and uses for same

    Science.gov (United States)

    Kim, Jungbae [Richland, WA

    2010-11-23

    Disclosed is a composition and method for fabricating novel hybrid materials comprised of, e.g., carbon nanotubes (CNTs) and crosslinked enzyme clusters (CECs). In one method, enzyme-CNT hybrids are prepared by precipitation of enzymes which are subsequently crosslinked, yielding crosslinked enzyme clusters (CECs) on the surface of the CNTs. The CEC-enzyme-CNT hybrids exhibit high activity per unit area or mass as well as improved enzyme stability and longevity over hybrid materials known in the art. The CECs in the disclosed materials permit multilayer biocatalytic coatings to be applied to surfaces providing hybrid materials suitable for use in, e.g., biocatalytic applications and devices as described herein.

  19. Substrate mediated enzyme prodrug therapy

    DEFF Research Database (Denmark)

    Fejerskov, Betina; Jarlstad Olesen, Morten T; Zelikin, Alexander N

    2017-01-01

    Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug administra......Substrate mediated enzyme prodrug therapy (SMEPT) is a biomedical platform developed to perform a localized synthesis of drugs mediated by implantable biomaterials. This approach combines the benefits and at the same time offers to overcome the drawbacks for traditional pill-based drug...

  20. Ionizing radiation effect on enzymes. I

    International Nuclear Information System (INIS)

    Libicky, A.; Chottova, O.; Fidlerova, J.; Urban, J.

    1980-01-01

    The effect was studied of gamma radiation on the proteolytic activity of pancreatin prepared either by separating enzymes from an activated extract of the pancreas, containing 2.15% of lipids, or by drying the not completely activated ground pancreas, containing 6.14% of lipids. A part of the first sample in which the proportion of lipids was additionally increased to 16.55% was also irradiated. The moisture content was practically the same in all three samples. The source of radiation was 60 Co, the dose rate 1.27 kGy/h. The samples of pancreatin in test-tubes were irradiated at 25 degC, doses ranging from 1x10 4 to 12x10 4 Gy. The results were statistically evaluated and are given in tables, and converted to the dried lipid-free substance they are expressed in graphs. The technological procedure of pancreatin preparation and the content of lipids do not influence the decrease in proteolytic activity (Graph 3). (author)

  1. Ionizing radiation effect on enzymes. II

    International Nuclear Information System (INIS)

    Libicky, A.; Fidlerova, J.; Urban, J.; Chottova, O.; Kubankova, V.

    1980-01-01

    The effects of gamma radiation on the efficacy of chymotrypsin in pancreatin prepared by the separation of enzymes from an activated pancreas extract, in the same sample in which the content of lipids was increased to 16.55%, and in pancreatin prepared by drying an incompletely activated ground pancreas were compared with the effect of radiation on crystaline lyophilized chymotrypsin. The working conditions were identical with those described in the previous communication, all samples possessed nearly identical humidity on irradiation. The efficacy of chymotrypsin was determined by the method of PhBs 3, ethyl ester L-tyrosine hydrochloride being used as the substrate. The results were statistically evaluated and after calculation for dried lipid-free substance represented in graphs. The sequence of the loss of efficacy in pancreatin corresponded to the sequence of the loss of the total proteolytic efficacy found in the previous communication. The lowest remaining efficacy was found in crystalline lyophilized chymotrypsin. Percent losses of chymotrypsin efficacy in pancreatin determined by the synthetic substrate were in good agreement with the loss of the total proteolytic efficacy of the same samples determined by casein. (author)

  2. Accessory enzymes influence cellulase hydrolysis of the model substrate and the realistic lignocellulosic biomass.

    Science.gov (United States)

    Sun, Fubao Fuebiol; Hong, Jiapeng; Hu, Jinguang; Saddler, Jack N; Fang, Xu; Zhang, Zhenyu; Shen, Song

    2015-11-01

    The potential of cellulase enzymes in the developing and ongoing "biorefinery" industry has provided a great motivation to develop an efficient cellulase mixture. Recent work has shown how important the role that the so-called accessory enzymes can play in an effective enzymatic hydrolysis. In this study, three newest Novozymes Cellic CTec cellulase preparations (CTec 1/2/3) were compared to hydrolyze steam pretreated lignocellulosic substrates and model substances at an identical FPA loading. These cellulase preparations were found to display significantly different hydrolytic performances irrelevant with the FPA. And this difference was even observed on the filter paper itself when the FPA based assay was revisited. The analysis of specific enzyme activity in cellulase preparations demonstrated that different accessory enzymes were mainly responsible for the discrepancy of enzymatic hydrolysis between diversified substrates and various cellulases. Such the active role of accessory enzymes present in cellulase preparations was finally verified by supplementation with β-glucosidase, xylanase and lytic polysaccharide monooxygenases AA9. This paper provides new insights into the role of accessory enzymes, which can further provide a useful reference for the rational customization of cellulase cocktails in order to realize an efficient conversion of natural lignocellulosic substrates. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Thermodynamics of Enzyme-Catalyzed Reactions Database

    Science.gov (United States)

    SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

  4. Curious Cases of the Enzymes.

    Science.gov (United States)

    Ulusu, Nuriye Nuray

    2015-07-01

    Life as we know it heavily relies on biological catalysis, in fact, in a very nonromantic version of it, life could be considered as a series of chemical reactions, regulated by the guarding principles of thermodynamics. In ancient times, a beating heart was a good sign of vitality, however, to me, it is actually the presence of active enzymes that counts… Though we do not usually pay attention, the history of enzymology is as old as humanity itself, and dates back to the ancient times. This paper is dedicated to these early moments of this remarkable science that touched our lives in the past and will make life a lot more efficient for humanity in the future. There was almost always a delicate, fundamentally essential relationship between mankind and the enzymes. Challenged by a very alien and hostile Nature full of predators, prehistoric men soon discovered the medicinal properties of the plants, through trial and error. In fact, they accidently discovered the enzyme inhibitors and thus, in crude terms, kindled a sparkling area of research. These plant-derivatives that acted as enzyme inhibitors helped prehistoric men in their pursuit of survival and protection from predators; in hunting and fishing… Later in history, while the underlying purposes of survival and increasing the quality of life stayed intact, the ways and means of enzymology experienced a massive transformation, as the 'trial and error' methodology of the ancients is now replaced with rational scientific theories.

  5. Enzymes with activity toward Xyloglucan

    NARCIS (Netherlands)

    Vincken, J.P.

    2003-01-01

    Xyloglucans are plant cell wall polysaccharides, which belong to the hemicellulose class. Here the structural variations of xyloglucans will be reviewed. Subsequently, the anchoring of xyloglucan in the plant cell wall will be discussed. Enzymes involved in degradation or modification of xyloglucan

  6. Heavy enzymes--experimental and computational insights in enzyme dynamics.

    Science.gov (United States)

    Swiderek, Katarzyna; Ruiz-Pernía, J Javier; Moliner, Vicent; Tuñón, Iñaki

    2014-08-01

    The role of protein motions in the chemical step of enzyme-catalyzed reactions is the subject of an open debate in the scientific literature. The systematic use of isotopically substituted enzymes has been revealed as a useful tool to quantify the role of these motions. According to the Born-Oppenheimer approximation, changing the mass of the protein does not change the forces acting on the system but alters the frequencies of the protein motions, which in turn can affect the rate constant. Experimental and theoretical studies carried out in this field are presented in this article and discussed in the framework of Transition State Theory. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Enzymic hydrolysis of xylans. I. A high xylanase and beta-xylosidase producing strain of Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Conrad, D.

    1981-01-01

    Aspergillus niger, strain 110.42 (CBS) was selected as a producer of high xylanolytic activities. The time course of xylanase and beta-xylosidase production as well as the effect of pH and temperature on the activity of these enzymes were studied. High-performance liquid chromatography analysis of the enzymic degradation of arabinoxylan showed a nearly complete conversion to pentose sugars. Aspects of using crude xylanase preparations for enzymic saccharification of xylans are discussed.

  8. Enzyme technology: Key to selective biorefining

    DEFF Research Database (Denmark)

    Meyer, Anne S.

    2014-01-01

    to the reaction is a unique trait of enzyme catalysis. Since enzyme selectivity means that a specific reaction is catalysed between particular species to produce definite products, enzymes are particularly fit for converting specific compounds in mixed biomass streams. Since enzymes are protein molecules...... their rational use in biorefinery processes requires an understanding of the basic features of enzymes and reaction traits with respect to specificity, kinetics, reaction optima, stability and structure-function relations – we are now at a stage where it is possible to use nature’s enzyme structures as starting...... point and then improve the functional traits by targeted mutation of the protein. The talk will display some of our recent hypotheses related to enzyme action, recently obtained results within knowledge-based enzyme improvements as well as cast light on research methods used in optimizing enzyme...

  9. Preparing for Surgery

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Preparing for Surgery Home For Patients Search FAQs Preparing for Surgery ... Surgery FAQ080, August 2011 PDF Format Preparing for Surgery Gynecologic Problems What is the difference between outpatient ...

  10. Study of DNA reconstruction enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, M [Kyushu Univ., Fukuoka (Japan). Faculty of Science

    1976-12-01

    Description was made of the characteristics and mechanism of 3 reconstructive enzymes which received from M. luteus or E. coli or T4, and of which natures were clarified as reconstructive enzymes of DNA irradiated with ultraviolet rays. As characteristics, the site of breaking, reaction, molecular weight, electric charge in the neutrality and a specific adhesion to DNA irradiated with ultraviolet rays were mentioned. As to mutant of ultraviolet ray sensitivity, hereditary control mechanism of removal and reconstruction by endo-nuclease activation was described, and suggestion was referred to removal and reconstruction of cells of xedoderma pigmentosum which is a hereditary disease of human. Description was also made as to the mechanism of exonuclease activation which separates dimer selectively from irradiated DNA.

  11. Metrological aspects of enzyme production

    International Nuclear Information System (INIS)

    Kerber, T M; Pereira-Meirelles, F V; Dellamora-Ortiz, G M

    2010-01-01

    Enzymes are frequently used in biotechnology to carry out specific biological reactions, either in industrial processes or for the production of bioproducts and drugs. Microbial lipases are an important group of biotechnologically valuable enzymes that present widely diversified applications. Lipase production by microorganisms is described in several published papers; however, none of them refer to metrological evaluation and the estimation of the uncertainty in measurement. Moreover, few of them refer to process optimization through experimental design. The objectives of this work were to enhance lipase production in shaken-flasks with Yarrowia lipolytica cells employing experimental design and to evaluate the uncertainty in measurement of lipase activity. The highest lipolytic activity obtained was about three- and fivefold higher than the reported activities of CRMs BCR-693 and BCR-694, respectively. Lipase production by Y. lipolytica cells aiming the classification as certified reference material is recommended after further purification and stability studies

  12. Consumer attitudes to enzymes in food production

    DEFF Research Database (Denmark)

    Søndergaard, Helle Alsted; Grunert, Klaus G.; Scholderer, Joachim

    2005-01-01

    The use of enzymes in food production has potential benefits for both food manufacturers and consumers. A central question is how consumers react to new ways of producing foods with enzymes. This study investigates the formation of consumer attitudes to different enzyme production methods in three...... European countries. Results show that consumers are most positive towards non-GM enzyme production methods. The enzyme production method is by far the most important factor for the formation of buying intentions compared to price and benefits. Results also show that environmental concern and attitudes...... to technological progress are the socio-political attitudes that have the highest predictive value regarding attitudes to enzyme production methods....

  13. Research progress of nanoparticles as enzyme mimetics

    Science.gov (United States)

    Hu, XiaoNa; Liu, JianBo; Hou, Shuai; Wen, Tao; Liu, WenQi; Zhang, Ke; He, WeiWei; Ji, YingLu; Ren, HongXuan; Wang, Qi; Wu, XiaoChun

    2011-10-01

    Natural enzymes as biological catalysts possess remarkable advantages, especially their highly efficient and selective catalysis under mild conditions. However, most natural enzymes are proteins, thus exhibiting an inherent low durability to harsh reaction conditions. Artificial enzyme mimetics have been pursued extensively to avoid this drawback. Quite recently, some inorganic nanoparticles (NPs) have been found to exhibit unique enzyme mimetics. In addition, their much higher stability overcomes the inherent disadvantage of natural enzymes. Furthermore, easy mass-production and low cost endow them more benefits. As a new member of artificial enzyme mimetics, they have received intense attention. In this review article, major progress in this field is summarized and future perspectives are highlighted.

  14. Allosteric regulation of epigenetic modifying enzymes.

    Science.gov (United States)

    Zucconi, Beth E; Cole, Philip A

    2017-08-01

    Epigenetic enzymes including histone modifying enzymes are key regulators of gene expression in normal and disease processes. Many drug development strategies to target histone modifying enzymes have focused on ligands that bind to enzyme active sites, but allosteric pockets offer potentially attractive opportunities for therapeutic development. Recent biochemical studies have revealed roles for small molecule and peptide ligands binding outside of the active sites in modulating the catalytic activities of histone modifying enzymes. Here we highlight several examples of allosteric regulation of epigenetic enzymes and discuss the biological significance of these findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Silica-Immobilized Enzyme Reactors

    Science.gov (United States)

    2007-08-01

    Silica-IMERs 14 implicated in neurological disorders such as Schizophrenia and Parkinson’s disease.[86] Drug discovery for targets that can alter the...primarily the activation of prodrugs and proantibiotics for cancer treatments or antibiotic therapy , respectively.[87] Nitrobenzene nitroreductase was...BuChE) Monolith disks* Packed Silica Biosilica Epoxide- Silica Silica-gel Enzyme Human AChE Human AChE Human AChE Equine BuChE Human

  16. Immobilised enzymes in biorenewable production

    OpenAIRE

    Franssen, M.C.R.; Steunenberg, P.; Scott, E.L.; Zuilhof, H.; Sanders, J.P.M.

    2013-01-01

    Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, ...

  17. Immobilization of enzymes by radiation

    International Nuclear Information System (INIS)

    Kaetsu, I.; Kumakura, M.; Yoshida, M.; Asano, M.; Himei, M.; Tamura, M.; Hayashi, K.

    1979-01-01

    Immobilization of various enzymes was performed by radiation-induced polymerization of glass-forming monomers at low temperatures. Alpha-amylase and glucoamylase were effectively immobilized in hydrophilic polymer carrier such as poly(2-hydroxyethyl methacrylate) and also in rather hydrophobic carrier such as poly(tetraethylene-glycol diacrylate). Immobilized human hemoglobin underwent the reversible oxygenation concomitantly with change of oxygen concentration outside of the matrices. (author)

  18. Characterisation of two bifunctional cellulase-xylanase enzymes isolated from a bovine rumen metagenome library

    CSIR Research Space (South Africa)

    Rashamuse, KJ

    2013-02-01

    Full Text Available ample raw material for fuel production [21] without causing reduction in food stock. Bio-fuel can be produced by pre-treatment, either physical or chemical, of cellulosic material, followed by fermentation of released sugars to yield fuel ethanol.... Currently cellulytic enzymes are used in the pre-treatment step [21, 19] to assist in degradation of cellulose to yield fermentable sugars. To reduce cost in biofuel production there is a need for enzyme preparations with broader substrate ranges...

  19. Immobilised enzymes in biorenewables production.

    Science.gov (United States)

    Franssen, Maurice C R; Steunenberg, Peter; Scott, Elinor L; Zuilhof, Han; Sanders, Johan P M

    2013-08-07

    Oils, fats, carbohydrates, lignin, and amino acids are all important raw materials for the production of biorenewables. These compounds already play an important role in everyday life in the form of wood, fabrics, starch, paper and rubber. Enzymatic reactions do, in principle, allow the transformation of these raw materials into biorenewables under mild and sustainable conditions. There are a few examples of processes using immobilised enzymes that are already applied on an industrial scale, such as the production of High-Fructose Corn Syrup, but these are still rather rare. Fortunately, there is a rapid expansion in the research efforts that try to improve this, driven by a combination of economic and ecological reasons. This review focusses on those efforts, by looking at attempts to use fatty acids, carbohydrates, proteins and lignin (and their building blocks), as substrates in the synthesis of biorenewables using immobilised enzymes. Therefore, many examples (390 references) from the recent literature are discussed, in which we look both at the specific reactions as well as to the methods of immobilisation of the enzymes, as the latter are shown to be a crucial factor with respect to stability and reuse. The applications of the renewables produced in this way range from building blocks for the pharmaceutical and polymer industry, transport fuels, to additives for the food industry. A critical evaluation of the relevant factors that need to be improved for large-scale use of these examples is presented in the outlook of this review.

  20. Self-powered enzyme micropumps

    Science.gov (United States)

    Sengupta, Samudra; Patra, Debabrata; Ortiz-Rivera, Isamar; Agrawal, Arjun; Shklyaev, Sergey; Dey, Krishna K.; Córdova-Figueroa, Ubaldo; Mallouk, Thomas E.; Sen, Ayusman

    2014-05-01

    Non-mechanical nano- and microscale pumps that function without the aid of an external power source and provide precise control over the flow rate in response to specific signals are needed for the development of new autonomous nano- and microscale systems. Here we show that surface-immobilized enzymes that are independent of adenosine triphosphate function as self-powered micropumps in the presence of their respective substrates. In the four cases studied (catalase, lipase, urease and glucose oxidase), the flow is driven by a gradient in fluid density generated by the enzymatic reaction. The pumping velocity increases with increasing substrate concentration and reaction rate. These rechargeable pumps can be triggered by the presence of specific analytes, which enables the design of enzyme-based devices that act both as sensor and pump. Finally, we show proof-of-concept enzyme-powered devices that autonomously deliver small molecules and proteins in response to specific chemical stimuli, including the release of insulin in response to glucose.

  1. Substrate mediated enzyme prodrug therapy.

    Directory of Open Access Journals (Sweden)

    Betina Fejerskov

    Full Text Available In this report, we detail Substrate Mediated Enzyme Prodrug Therapy (SMEPT as a novel approach in drug delivery which relies on enzyme-functionalized cell culture substrates to achieve a localized conversion of benign prodrug(s into active therapeutics with subsequent delivery to adhering cells or adjacent tissues. For proof-of-concept SMEPT, we use surface adhered micro-structured physical hydrogels based on poly(vinyl alcohol, β-glucuronidase enzyme and glucuronide prodrugs. We demonstrate enzymatic activity mediated by the assembled hydrogel samples and illustrate arms of control over rate of release of model fluorescent cargo. SMEPT was not impaired by adhering cells and afforded facile time - and dose - dependent uptake of the in situ generated fluorescent cargo by hepatic cells, HepG2. With the use of a glucuronide derivative of an anticancer drug, SN-38, SMEPT afforded a decrease in cell viability to a level similar to that achieved using parent drug. Finally, dose response was achieved using SMEPT and administration of judiciously chosen concentration of SN-38 glucuronide prodrug thus revealing external control over drug delivery using drug eluting surface. We believe that this highly adaptable concept will find use in diverse biomedical applications, specifically surface mediated drug delivery and tissue engineering.

  2. Fluorogenic Substrates for Visualizing Acidic Organelle Enzyme Activities.

    Directory of Open Access Journals (Sweden)

    Fiona Karen Harlan

    Full Text Available Lysosomes are acidic cytoplasmic organelles that are present in all nucleated mammalian cells and are involved in a variety of cellular processes including repair of the plasma membrane, defense against pathogens, cholesterol homeostasis, bone remodeling, metabolism, apoptosis and cell signaling. Defects in lysosomal enzyme activity have been associated with a variety of neurological diseases including Parkinson's Disease, Lysosomal Storage Diseases, Alzheimer's disease and Huntington's disease. Fluorogenic lysosomal staining probes were synthesized for labeling lysosomes and other acidic organelles in a live-cell format and were shown to be capable of monitoring lysosomal metabolic activity. The new targeted substrates were prepared from fluorescent dyes having a low pKa value for optimum fluorescence at the lower physiological pH found in lysosomes. They were modified to contain targeting groups to direct their accumulation in lysosomes as well as enzyme-cleavable functions for monitoring specific enzyme activities using a live-cell staining format. Application to the staining of cells derived from blood and skin samples of patients with Metachromatic Leukodystrophy, Krabbe and Gaucher Diseases as well as healthy human fibroblast and leukocyte control cells exhibited localization to the lysosome when compared with known lysosomal stain LysoTracker® Red DND-99 as well as with anti-LAMP1 Antibody staining. When cell metabolism was inhibited with chloroquine, staining with an esterase substrate was reduced, demonstrating that the substrates can be used to measure cell metabolism. When applied to diseased cells, the intensity of staining was reflective of lysosomal enzyme levels found in diseased cells. Substrates specific to the enzyme deficiencies in Gaucher or Krabbe disease patient cell lines exhibited reduced staining compared to that in non-diseased cells. The new lysosome-targeted fluorogenic substrates should be useful for research

  3. Actinomycete enzymes and activities involved in straw saccharification

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, A J; Ball, A S [Liverpool Univ. (UK). Dept. of Genetics and Microbiology

    1990-01-01

    This research programme has been directed towards the analysis of actinomycete enzyme systems involved in the degradation of plant biomass (lignocellulose.) The programme was innovative in that a novel source of enzymes was systematically screened and wheat straw saccharifying activity was the test criterion. Over 200 actinomycete strains representing a broad taxonomic range were screened. A range of specific enzyme activities were involved and included cellulase, xylanase, arabinofuranosidase, acetylesterase, {beta}-xylosidase and {beta}-glucosidase. Since hemicellulose (arabinoxylan) was the primary source of sugar, xylanases were characterized. The xylan-degrading systems of actinomycetes were complex and nonuniform, with up to six separate endoxylanases identified in active strains. Except for microbispora bispora, actinomycetes were found to be a poor source of cellulase activity. Evidence for activity against the lignin fraction of straw was produced for a range of actinomycete strains. While modification reactions were common, cleavage of inter-monomer bonds, and utilization of complex polyphenolic compounds were restricted to two strains: Thermomonospora mesophila and Streptomyces badius. Crude enzyme preparations from actinomycetes can be used to generate sugar, particularly pentoses, directly from cereal straw. The potential for improvements in yield rests with the formulation to cooperative enzyme combinations from different strains. The stability properties of enzymes from thermophilic strains and the general neutral to alkali pH optima offer advantages in certain process situations. Actinomycetes are a particularly rich source of xylanases for commercial application and can rapidly solubilise a lignocarbohydrate fraction of straw which may have both product and pretreatment potential. 31 refs., 4 figs., 5 tabs.

  4. Improvement of fish freshness determination method by the application of amorphous freeze-dried enzymes.

    Science.gov (United States)

    Srirangsan, Paveena; Hamada-Sato, Naoko; Kawai, Kiyoshi; Watanabe, Manabu; Suzuki, Toru

    2010-12-08

    Alkaline phosphatase (ALP), nucleoside phosphorylase (NP), and xanthine oxidase (XOD) were used in a colorimetric method for evaluation of fish freshness based on the Ki value. Two enzyme mixtures, NP-XOD and ALP-NP-XOD, were prepared with a color developing agent, and stabilities of the enzymes were improved by freeze-drying with glass-forming additives, i.e., sucrose and sucrose-gelatin. As a result, a linear relationship was obtained between the Ki values determined by the developed colorimetric method and a conventional high-performance liquid chromatography with a high correlation coefficient of 0.997. All enzyme samples containing the additive(s) were amorphous, and higher enzymes activities were maintained compared to those freeze-dried without an additive. Sucrose-gelatin/enzyme mixtures showed higher glass transition temperature; consequently, the enzymes were better stabilized than the sucrose/enzyme formulations. Using the sucrose-gelatin/enzyme mixture, Ki values of fish meat could be accurately determined even after 6-month storage of the dried enzymes at 40 °C.

  5. Preparation and Characterization of Some Polyethylene Modified- Starch Biodegradable Films

    International Nuclear Information System (INIS)

    Badrana, A.S.; Ramadanb, A.M.; Ibrahim, N.A.; Kahild, T.; Hussienc, H.A.

    2005-01-01

    Blends of LDPE with soluble starch, wheat flour and commercial starch were prepared by mixing starch (or flour) with styrene then blending the mixture with LDPE, The starch percents vary between 5 and 50% of the total weight. Their physical and mechanical properties were recorded and compared with pure LDPE. It was observed that the increase in starch or wheat flour contents of the mixture was reversibly proportional to the tensile strength and % elongation. Samples were tested for water absorption. All of the samples were insoluble in cold and boiling water. Moisture uptake increased with immersion time and increasing starch content. The changes in the tensile strength of LDPE/starch (or wheat flour) after the course of thermal oxidation was measured. These results show negligible changes in the tensile strength of the control sample as compared to that of the samples containing the additives. Oxidation processes take advantage of the high temperatures (40-50 degree C) and the time. It was also observed that after 10 weeks of soil burial, the mechanical properties of the films decrease, mainly, due to starch removal from the films. Also, for the weight loss a drastic decrease was observed after 10 weeks of soil burial thereafter it preceded slowly. The LDPE/ starch strips showed weight loss after treating with a-amylase this due to hydrolysis and leaching of the starch. The rate of starch hydrolysis increases with the increase in starch content of the sample. The influence of addition of starch on the overall migration of these films, with different food simulant, was studied, at different temperatures (-4 degree. 25 degree and 40 degree C). All values were significantly lower than the upper limit for overall migration set by the EU (10 mg/dirf) for food grade plastics packaging materials

  6. The preparation of radioactivity labelled DNA

    International Nuclear Information System (INIS)

    Ballance, P.; Morgan, J.; McGregor, G.; Durkacz, B.

    1984-01-01

    The nick translation reaction, which uses the endonuclease enzyme to incorporate pieces of DNA into the genetic material of other organisms, is being used more and more in Molecular Biology research for the preparation of pure DNA labelled with 32 P. However results are presented which show that high radiation doses are received by the hands of nick translation workers. A Scheme of Work to reduce these doses is described. (author)

  7. Electro-ultrafiltration of industrial enzyme solutions

    DEFF Research Database (Denmark)

    Enevoldsen, Ann Dorrit; Hansen, Erik Børresen; Jonsson, Gunnar Eigil

    2007-01-01

    To reduce the problems with fouling and concentration polarization during crossflow ultrafiltration of industrial enzyme solutions an electric field is applied across the membrane. The filtration performance during electro-ultrafiltration (EUF) has been tested with several enzymes. Results show...

  8. Biochemical characterization of thermostable cellulase enzyme from ...

    African Journals Online (AJOL)

    user

    2012-05-29

    May 29, 2012 ... tested for their ability to produce cellulase complex enzyme by growing on a defined substrates as well ... In the current industrial processes, cellulolytic enzymes ... energy sources such as glucose, ethanol, hydrogen and.

  9. Epigenetics of dominance for enzyme activity

    Indian Academy of Sciences (India)

    Unknown

    dimer over a wide range of H+ concentrations accounts for the epigenetics of dominance for enzyme activity. [Trehan K S ... The present study has been carried on acid phosphatase .... enzyme activity over mid parent value (table 3, col. 13),.

  10. Castor Oil Transesterification Catalysed by Liquid Enzymes

    DEFF Research Database (Denmark)

    Andrade, Thalles; Errico, Massimiliano; Christensen, Knud Villy

    2017-01-01

    In the present work, biodiesel production by reaction of non-edible castor oil with methanol under enzymatic catalysis is investigated. Two liquid enzymes were tested: Eversa Transform and Resinase HT. Reactions were performed at 35 °C and with a molar ratio of methanol to oil of 6:1. The reaction...... time was 8 hours. Stepwise addition of methanol was necessary to avoid enzyme inhibition by methanol. In order to minimize the enzyme costs, the influence of enzyme activity loss during reuse of both enzymes was evaluated under two distinct conditions. In the former, the enzymes were recovered...... and fully reused; in the latter, a mixture of 50 % reused and 50 % fresh enzymes was tested. In the case of total reuse after three cycles, both enzymes achieved only low conversions. The biodiesel content in the oil-phase using Eversa Transform was 94.21 % for the first cycle, 68.39 % in the second, and 33...

  11. Harmonisation of seven common enzyme results through EQA.

    Science.gov (United States)

    Weykamp, Cas; Franck, Paul; Gunnewiek, Jacqueline Klein; de Jonge, Robert; Kuypers, Aldy; van Loon, Douwe; Steigstra, Herman; Cobbaert, Christa

    2014-11-01

    Equivalent results between different laboratories enable optimal patient care and can be achieved with harmonisation. We report on EQA-initiated national harmonisation of seven enzymes using commutable samples. EQA samples were prepared from human serum spiked with human recombinant enzymes. Target values were assigned with the IFCC Reference Measurement Procedures. The same samples were included at four occasions in the EQA programmes of 2012 and 2013. Laboratories were encouraged to report IFCC traceable results. A parallel study was done to confirm commutability of the samples. Of the 223 participating laboratories, 95% reported IFCC traceable results, ranging from 98% (ASAT) to 87% (amylase). Users of Roche and Siemens (97%) more frequently reported in IFCC traceable results than users of Abbott (91%), Beckman (90%), and Olympus (87%). The success of harmonisation, expressed as the recovery of assigned values and the inter-laboratory CV was: ALAT (recovery 100%; inter-lab CV 4%), ASAT (102%; 4%), LD (98%; 3%), CK (101%; 5%), GGT (98%; 4%), AP (96%; 6%), amylase (99%; 4%). There were no significant differences between the manufacturers. Commutability was demonstrated in the parallel study. Equal results in the same sample in the 2012 and 2013 EQA programmes demonstrated stability of the samples. The EQA-initiated national harmonisation of seven enzymes, using stable, commutable human serum samples, spiked with human recombinant enzymes, and targeted with the IFCC Reference Measurement Procedures, was successful in terms of implementation of IFCC traceable results (95%), recovery of the target (99%), and inter-laboratory CV (4%).

  12. Zymography methods for visualizing hydrolytic enzymes

    OpenAIRE

    Vandooren, Jennifer; Geurts, Nathalie; Martens, Erik; Van den Steen, Philippe E.; Opdenakker, Ghislain

    2013-01-01

    Zymography is a technique for studying hydrolytic enzymes on the basis of substrate degradation. It is a powerful., but often misinterpreted, tool. yielding information on potential. hydrolytic activities, enzyme forms and the locations of active enzymes. In this Review, zymography techniques are compared in terms of advantages, limitations and interpretations. With in gel zymography, enzyme forms are visualized according to their molecular weights. Proteolytic activities are localized in tis...

  13. Biomedical Applications of Enzymes From Marine Actinobacteria.

    Science.gov (United States)

    Kamala, K; Sivaperumal, P

    Marine microbial enzyme technologies have progressed significantly in the last few decades for different applications. Among the various microorganisms, marine actinobacterial enzymes have significant active properties, which could allow them to be biocatalysts with tremendous bioactive metabolites. Moreover, marine actinobacteria have been considered as biofactories, since their enzymes fulfill biomedical and industrial needs. In this chapter, the marine actinobacteria and their enzymes' uses in biological activities and biomedical applications are described. © 2017 Elsevier Inc. All rights reserved.

  14. The inhibitory effect of convulsant agents on the enzyme in brain which inactivates nerveside.

    Science.gov (United States)

    Toh, C C

    1969-07-01

    1. An enzyme which can be extracted from brain inactivates nerveside in the optimum pH range 5.8-7.0.2. The polybasic acids trypan blue and its analogue trypan red, bromphenol blue and its analogue bromthymol blue at concentrations of 0.22 mM and ethylenediaminetetra-acetic acid (EDTA) at a concentration of 1 mM are strong inhibitors of the enzyme.3. Penicillin which is a monobasic carboxylic acid also inhibits the enzyme but only if concentrations as high as 3.6 mM are used. The antibiotic streptomycin which is a basic substance does not inhibit the enzyme.4. Caffeine at a concentration of 7.2 mM only weakly inhibits the enzyme.5. Chymotrypsin and wheat germ acid phosphatase also inactivate nerveside at pH 5.9 and are inhibited by the acidic dyes and penicillin. EDTA inhibits wheat germ phosphatase but activates chymotrypsin.6. Inactivation of nerveside by the brain enzyme and by wheat germ phosphatase is different from the action of chymotrypsin. Nerveside solutions incubated with chymotrypsin completely lose all biological activity whereas if incubation is carried out with either the brain enzyme or wheat germ acid phosphatase a residual biological activity remains even when the concentration of these two enzymes is increased. This residual biological activity is due to a peptide as it is destroyed by chymotrypsin.7. The manner in which nerveside is inactivated by the brain enzyme is uncertain as the preparation of the latter contained phosphodiesterase and protease activities which were similarly inhibited by the acid dyes, penicillin and EDTA.8. Pentylenetetrazole, picrotoxin, strychnine and tetanus toxin do not inhibit the brain enzyme.9. The nerveside-inactivating enzyme is not identical with the Substance P-inactivating enzyme in brain as the former is inhibited by EDTA while the latter is not.

  15. Purification and characterization of extracellular amylolytic enzyme ...

    African Journals Online (AJOL)

    In the present study, the amylase enzyme producing potential of four different Aspergillus species was analyzed. The extracted amylase enzyme was purified by diethyl amino ethyl (DEAE) cellulose and Sephadex G-50 column chromatography and the enzyme activity was measured by using synthetic substrate starch.

  16. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  17. PROCESS FOR DUST-FREE ENZYME MANUFACTURE

    NARCIS (Netherlands)

    Andela, C.; Feijen, Jan; Dillissen, Marc

    1994-01-01

    New enzyme granules are provided with improved properties. The granules are based on core particles having a good pore size and pore size distribution to allow an enzyme solution to enter into the particle. Accordingly, the core material comprises the enzyme in liquid form, thus eliminating the

  18. A metal-based inhibitor of NEDD8-activating enzyme.

    Directory of Open Access Journals (Sweden)

    Hai-Jing Zhong

    Full Text Available A cyclometallated rhodium(III complex [Rh(ppy(2(dppz](+ (1 (where ppy=2-phenylpyridine and dppz=dipyrido[3,2-a:2',3'-c]phenazine dipyridophenazine has been prepared and identified as an inhibitor of NEDD8-activating enzyme (NAE. The complex inhibited NAE activity in cell-free and cell-based assays, and suppressed the CRL-regulated substrate degradation and NF-κB activation in human cancer cells with potency comparable to known NAE inhibitor MLN4924. Molecular modeling analysis suggested that the overall binding mode of 1 within the binding pocket of the APPBP1/UBA3 heterodimer resembled that for MLN4924. Complex 1 is the first metal complex reported to suppress the NEDDylation pathway via inhibition of the NEDD8-activating enzyme.

  19. Galectin-4 and small intestinal brush border enzymes form clusters

    DEFF Research Database (Denmark)

    Danielsen, E M; van Deurs, B

    1997-01-01

    that galectin-4 is indeed an intestinal brush border protein; we also localized galectin-4 throughout the cell, mainly associated with membraneous structures, including small vesicles, and to the rootlets of microvillar actin filaments. This was confirmed by subcellular fractionation, showing about half...... by a nonclassical pathway, and the brush border enzymes represent a novel class of natural ligands for a member of the galectin family. Newly synthesized galectin-4 is rapidly "trapped" by association with intracellular structures prior to its apical secretion, but once externalized, association with brush border......Detergent-insoluble complexes prepared from pig small intestine are highly enriched in several transmembrane brush border enzymes including aminopeptidase N and sucrase-isomaltase, indicating that they reside in a glycolipid-rich environment in vivo. In the present work galectin-4, an animal lectin...

  20. Method for enzyme synthesis of radioactive thymine 5'-deoxyribonucleotides

    International Nuclear Information System (INIS)

    Nejedly, Z.; Ekl, J.; Hybs, K.; Kolina, J.; Filip, J.; Votruba, I.; Skoda, J.

    1978-01-01

    The enzyme synthesis is described for thymidine-5'-monophosphate, thymidine-5'-diphosphate and thymidine-5'-triphosphate specifically or nonspecifically labelled with 14 C or 3 H. The anabolic transformation of radioactive thymine to radioactive thymine 5'-deoxyribonucleotides is catalyzed by the action of enzyme preparations separated from Escherichia coli bacteria. It is achieved by the action of nonpurified cell-free extracts on special auxotrophic mutants of the thymine-dependent Escherichia coli SPT - strain in the presence of deoxyriboso-1-phosphate and adenosine-5'-triphosphate. The radioactive thymidine-5'-monophosphate may further be phosphorylated. In reaction mixtures, radioactive thymine, deoxyriboso-1-phosphate and adenosine-5'-triphosphate are used in molar ratios of 1:1:2 to 1:10:100, the optimum molar ratio being 1:5:10. (B.S.)

  1. Photosynthetic carboxylating enzymes in Phaeodactylum tricornutum: assay methods and properties

    Energy Technology Data Exchange (ETDEWEB)

    Mukerji, D [Bigelow Lab. for Ocean Sciences, West Boothbay Harbor, ME; Morris, I

    1976-01-01

    Rapid freezing (in liquid nitrogen) of the marine diatom Phaeodactylum tricornutum Bohlin followed by thawing permits a convenient and sensitive measurement of the activities of carboxylating enzymes without the need to prepare a cell-free extract. Using this method, the properties of RuDP and PEP carboxylases have been compared with those assayed in cell-free extracts. The most significant difference was in the Michaelis' constants (K/sub m/'s), the values being lower in the freeze/thaw assay. The absolute rate of carbon-dioxide fixation by the enzymes was less than the rate of photosynthesis by the intact alga. Significantly, the activity of PEP carboxylase was comparable (in some experiments, greater) to that of RuDP carboxylase. The significance of this and the possibility of an enzymatic approach to measurements of marine primary productivity are discussed.

  2. Lipolysis og different oils using crude enzyme isolate from the intestinal tract of rainbow trout, Oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Göttsche, J.R.; Nielsen, Nina Skall; Nielsen, Henrik Hauch

    2005-01-01

    Crude enzyme isolate was prepared from the intestine of rainbow trout. Positional specificity of the crude enzyme isolate was determined from both 1(3)- and 2-MAG products after i n vitro lipolysis of radioactive-labeled triolein. The ratio of 2- MAG/1(3)-MAG was 2:1, suggesting that the overall...... lipase specificity of the enzyme isolate from rainbow trout tended to be 1,3-specific; however, activity against the sn -2 position also was shown. In vitro lipolysis of four different unlabeled oils was performed with the crude enzyme isolate. The oils were: structured lipid [SL; containing the medium...

  3. Phosphoenolpyruvate-dependent protein kinase enzyme I of Streptococcus faecalis: purification and properties of the enzyme and characterization of its active center

    International Nuclear Information System (INIS)

    Alpert, C.A.; Frank, R.; Stueber, K.D.; Deutscher, J.; Hengstenberg, W.

    1985-01-01

    Enzyme I, the phosphoenolpyruvate:protein phosphotransferase (EC 2.7.3.9), which is part of the bacterial phosphoenolpyruvate-(PEP) dependent phosphotransferase system, has been purified from Streptococcus faecalis by using a large-scale preparation. Size exclusion chromatography revealed a molecular weight of 140,000. On sodium dodecyl sulfate gels, enzyme I gave one band with a molecular weight of 70,000, indicating that enzyme I consists of two identical subunits. The first 59 amino acids of the amino-terminal part of the protein have been sequenced. It showed some similarities with enzyme I of Salmonella typhimurium. The active center of enzyme I has also been determined. After phosphorylation with [ 32 P]PEP, the enzyme was cleaved by using different proteases. Labeled peptides were isolated by high-performance liquid chromatography on a reversed-phase column. The amino acid composition or amino acid sequence of the peptides has been determined. The largest labeled peptide was obtained with Lys-C protease and had the following sequence: -Ala-Phe-Val-Thr-Asp-Ile-Gly- Gly-Arg-Thr-Ser-His*-Ser-Ala-Ile-Met-Ala-Arg-Ser-Leu-Glu-Ile-Pro-Ala- Ile-Val-Gly-Thr-Lys-. It has previously been shown that the phosphoryl group is bound to the N-3 position of a histidyl residue in phosphorylated enzyme I. The single His in position 12 of the above peptide must therefore carry the phosphoryl group

  4. Enzyme structure and interaction with inhibitors

    International Nuclear Information System (INIS)

    London, R.E.

    1983-01-01

    This article reviews some of the results of studies on the 13 C-labeled enzyme dihydrofolate reductase (DHFR). Nuclear magnetic resonance (NMR) techniques are used in combination with isotopic labeling to learn about the structure and dynamics of this enzyme. 13 C-labeling is used for the purpose of studying enzyme/substrate and enzyme/inhibitor interactions. A second set of studies with DHFR was designed to investigate the basis for the high affinity between the inhibitor methotrexate and DHFR. The label was placed on the inhibitor, rather than the enzyme

  5. Hydrolytic enzymes in the central vacuole of plant cells.

    Science.gov (United States)

    Boller, T; Kende, H

    1979-06-01

    The hydrolase content of vacuoles isolated from protoplasts of suspension-cultured tobacco cells, of tulip petals, and of pineapple leaves, and the sedimentation behavior of tobacco tonoplasts were studied. Three precautions were found to be important for the analysis of vacuolar hydrolases and of the tonoplast. (a) Purification of protoplasts in a Ficoll gradient was necessary to remove cell debris which contained contaminating hydrolases adsorbed from the fungal cell-wall-degrading enzyme preparation. (b) Hydrolase activities in the homogenates of the intact cells or the tissue used and of the purified protoplasts had to be compared to verify the absence of contaminating hydrolases in the protoplast preparation. (c) Vacuoles obtained from the protoplasts by an osmotic shock had to be purified from the lysate in a Ficoll gradient. Since the density of the central vacuole approximates that of the protoplasts, about a 10% contamination of the vacuolar preparation by surviving protoplasts could not be eliminated and had to be taken into account when the distribution of enzymes and of radioactivity was calculated.THE INTRACELLULAR ACTIVITIES OF THE FOLLOWING ACID HYDROLASES WERE PRIMARILY LOCALIZED IN THE VACUOLE OF TOBACCO CELLS: alpha-mannosidase, beta-N-acetylglucosaminidase, beta-fructosidase, nuclease, phosphatase, phosphodiesterase. A similar composition of acid hydrolases was found in vacuoles obtained from protoplasts of tulip petals. Proteinase, a hydrolase with low activity in tobacco cells and tulip petals and therefore difficult to localize unequivocally, was found to be vacuolar in pineapple leaves, a tissue containing high levels of this enzyme. Our data support the hypothesis that the central vacuole of higher plant cells has an enzyme composition analogous to that of the animal lysosome.None of the vacuolar enzymes investigated was found to be bound to the tonoplast. When vacuoles were isolated from cells labeled with radioactive choline, the vacuolar

  6. DNA-Based Enzyme Reactors and Systems

    Directory of Open Access Journals (Sweden)

    Veikko Linko

    2016-07-01

    Full Text Available During recent years, the possibility to create custom biocompatible nanoshapes using DNA as a building material has rapidly emerged. Further, these rationally designed DNA structures could be exploited in positioning pivotal molecules, such as enzymes, with nanometer-level precision. This feature could be used in the fabrication of artificial biochemical machinery that is able to mimic the complex reactions found in living cells. Currently, DNA-enzyme hybrids can be used to control (multi-enzyme cascade reactions and to regulate the enzyme functions and the reaction pathways. Moreover, sophisticated DNA structures can be utilized in encapsulating active enzymes and delivering the molecular cargo into cells. In this review, we focus on the latest enzyme systems based on novel DNA nanostructures: enzyme reactors, regulatory devices and carriers that can find uses in various biotechnological and nanomedical applications.

  7. Hydrolytic enzymes in the central vacuole of plant cells

    International Nuclear Information System (INIS)

    Boller, T.; Kende, H.

    1979-01-01

    The hydrolase content of vacuoles isolated from protoplasts of suspension-cultured tobacco cells, of tulip petals, and pineapple leaves, and the sedimentation behavior of tobacco tonoplasts were studied. Three precautions were found to be important for the analysis of vacuolar hydrolases and of the tonoplast: (a) purification of protoplasts in a Ficoll gradient was necessary to remove cell debris which contained contaminating hydrolases adsorbed from the fungal cell-wall-degrading enzyme preparation; (b) hydrolase activities in the homogenates of the intact cells or the tissue used and of the purified protoplasts had to be compared to verify the absence of contaminating hydrolases in the protoplast preparation; and (c) vacuoles obtained from the protoplasts by an osmotic shock had to be purified from the lysate in a Ficoll gradient. Since the density of the central vacuole approximates that of the protoplasts, about a 10% contamination of the vacuolar preparation by surviving protoplasts could not be eliminated. The intracellular activities of the following acid hydrolases were primarily localized in the vacuole of tobacco cells: α-mannosidase, β-N-acetylglucosaminidase, β-fructosidase, nuclease, phosphatase, phosphodiesterase. A similar composition of acid hydrolases was found in vacuoles obtained from protoplasts of tulip petals. Proteinase, a hydrolase with low activity in tobacco cells and tulip petals was found to be vacuolar in pineapple leaves, a tissue containing high levels of this enzyme. None of the vacuolar enzymes investigated ws found to be bound to the tonoplast. When vacuoles were isolated from cells labeled with radioactive choline, the vacuolar membrane was found to contain radioactivity. On sucrose gradients, the label incorporated into tonoplasts banded around a density of 1.10 grams per cubic centimeter

  8. Simultaneously and separately immobilizing incompatible dual-enzymes on polymer substrate via visible light induced graft polymerization

    Science.gov (United States)

    Zhu, Xing; He, Bin; Zhao, Changwen; Ma, Yuhong; Yang, Wantai

    2018-04-01

    Developing facile and mild strategy to construct multi-enzymes immobilization system has attracted considerable attentions in recent years. Here a simple immobilization strategy called visible light induced graft polymerization that can simultaneously and separately encapsulate two kinds of enzymes on one polymer film was proposed. Two incompatible enzymes, trypsin and transglutaminase (TGase) were selected as model dual-enzymes system and simultaneously immobilized on two sides of low-density polyethylene (LDPE) film. After immobilization, it was found that more than 90% of the enzymes can be embedded into dual-enzymes loaded film without leakage. And the activities of both separately immobilized enzymes were higher than the activities of mixed co-immobilized enzymes or the sequential immobilized ones. This dual-enzymes loaded film (DEL film) showed excellent recyclability and can retain >87% activities of both enzymes after 4 cycles of utilization. As an example, this DEL film was used to conjugate a prodrug of cytarabine with a target peptide. The successful preparation of expected product demonstrated that the separately immobilized two enzymes can worked well together to catalyze a two-step reaction.

  9. Optimisation of synergistic biomass-degrading enzyme systems for efficient rice straw hydrolysis using an experimental mixture design.

    Science.gov (United States)

    Suwannarangsee, Surisa; Bunterngsook, Benjarat; Arnthong, Jantima; Paemanee, Atchara; Thamchaipenet, Arinthip; Eurwilaichitr, Lily; Laosiripojana, Navadol; Champreda, Verawat

    2012-09-01

    Synergistic enzyme system for the hydrolysis of alkali-pretreated rice straw was optimised based on the synergy of crude fungal enzyme extracts with a commercial cellulase (Celluclast™). Among 13 enzyme extracts, the enzyme preparation from Aspergillus aculeatus BCC 199 exhibited the highest level of synergy with Celluclast™. This synergy was based on the complementary cellulolytic and hemicellulolytic activities of the BCC 199 enzyme extract. A mixture design was used to optimise the ternary enzyme complex based on the synergistic enzyme mixture with Bacillus subtilis expansin. Using the full cubic model, the optimal formulation of the enzyme mixture was predicted to the percentage of Celluclast™: BCC 199: expansin=41.4:37.0:21.6, which produced 769 mg reducing sugar/g biomass using 2.82 FPU/g enzymes. This work demonstrated the use of a systematic approach for the design and optimisation of a synergistic enzyme mixture of fungal enzymes and expansin for lignocellulosic degradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Plant Products for Pharmacology: Application of Enzymes in Their Transformations

    Directory of Open Access Journals (Sweden)

    Marie Zarevúcka

    2008-12-01

    Full Text Available Different plant products have been subjected to detailed investigations due to their increasing importance for improving human health. Plants are sources of many groups of natural products, of which large number of new compounds has already displayed their high impact in human medicine. This review deals with the natural products which may be found dissolved in lipid phase (phytosterols, vitamins etc.. Often subsequent convenient transformation of natural products may further improve the pharmacological properties of new potential medicaments based on natural products. To respect basic principles of sustainable and green procedures, enzymes are often employed as efficient natural catalysts in such plant product transformations. Transformations of lipids and other natural products under the conditions of enzyme catalysis show increasing importance in environmentally safe and sustainable production of pharmacologically important compounds. In this review, attention is focused on lipases, efficient and convenient biocatalysts for the enantio- and regioselective formation / hydrolysis of ester bond in a wide variety of both natural and unnatural substrates, including plant products, eg. plant oils and other natural lipid phase compounds. The application of enzymes for preparation of acylglycerols and transformation of other natural products provides big advantage in comparison with employing of conventional chemical methods: Increased selectivity, higher product purity and quality, energy conservation, elimination of heavy metal catalysts, and sustainability of the employed processes, which are catalyzed by enzymes. Two general procedures are used in the transformation of lipid-like natural products: (a Hydrolysis/alcoholysis of triacylglycerols and (b esterification of glycerol. The reactions can be performed under conventional conditions or in supercritical fluids/ionic liquids. Enzyme-catalyzed reactions in supercritical fluids combine the

  11. Armored Urease: Enzyme-Bioconjugated Poly(acrylamide) Hydrogel as a Storage and Sensing Platform.

    Science.gov (United States)

    Kunduru, Konda R; Kutcherlapati, S N Raju; Arunbabu, Dhamodaran; Jana, Tushar

    2017-01-01

    Jack bean urease is an important enzyme not only because of its numerous uses in medical and other fields but also because of its historical significance-the first enzyme to be crystallized and also the first nickel metalloenzyme. This enzyme hydrolyzes urea into ammonia and carbon dioxide; however, the stability of this enzyme at ambient temperature is a bottleneck for its applicability. To improve urease stability, it was immobilized on different substrates, particularly on polymeric hydrogels. In this study, the enzyme was coupled covalently with poly(acrylamide) hydrogel with an yield of 18μmol/cm 3 . The hydrogel served as the nanoarmor and protected the enzyme against denaturation. The enzyme immobilized on the polymer hydrogel showed no loss in activity for more than 30 days at ambient temperature, whereas free enzyme lost its activity within a couple of hours. The Michaelis-Menten constant (K m ) for free and immobilized urease were 0.0256 and 0.2589mM, respectively, on the first day of the study. The K m of the immobilized enzyme was approximately 10 times higher than that of the free enzyme. The hydrogel technique was also used to prepare light diffracting polymerized colloidal crystal array in which urease enzyme was covalently immobilized. This system was applied for the detection of mercury (Hg 2+ ) with the lower limit as 1ppb, which is below the maximum contaminant limit (2ppb) for mercury ions in water. The experimental details of these studies are presented in this chapter. © 2017 Elsevier Inc. All rights reserved.

  12. The Use of Copper- 64 in the Investigation of Reaction Mechanisms of Enzymes, Particularly as Related to Food Processing; Emploi de Cuivre-64 dans l'Etude des Mecanismes de Reaction des Enzymes, Notamment en Ce Qui Concerne la Preparation des Denrees Alimentaires; ПРИМЕНЕНИЕ МЕДИ-64 ДЛЯ ИССЛЕДОВАНИЯ МЕХАНИЗМОВ ФЕРМЕНТАТИВНЫХ РЕАКЦИЙ, СВЯЗАННЫХ С ОБРАБОТКОЙ ПИЛИ; Empleo de Cobre-64 en el Estudio de los Mecanismos de Reacciones Enzima Ticas de Interes para la Elaboracion de Alimentos

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Jr., J. C.; McLemore, T. A. [Southern Regional Research Laboratory, New Orleans, LA (United States)

    1963-03-15

    The oxidative enzymes of plant tissues are often dormant or only slightly active during the resting state, becoming active on the injury of the tissue or on separation from the tissue. During food processing this results in an acceleration of the oxidation of the natural substrates and polymerization of the products, which discolour the tissue. Copper oxidases are the principal enzymes involved in catalysing these reactions. The activation of the enzyme also leads to its reaction inactivation. One of the causes of the phenomenon of reaction inactivation is the decrease in the effective concentration of the enzyme, probably by the removal or binding of its metal prosthetic group copper. By using copper- 64, in vitro, it was shown that, in a resting solution, cupric ion can complex and/or exchange with the copper of the enzyme and that, in oxidizing solutions, an additional amount of cupric ion can be complexed. Cu-o-quinone- type complexes have higher formation constants than Cu-p-quinone- type complexes. The amount of cupric ion complexed was decreased, if the ion was added in an oxidizing solution after the initiation of polymerization of the o-quinone type reaction products. The kinetics of the exchange and complexing processes for cupric ions with enzyme and reaction products are discussed mathematically. (author) [French] Les enzymes oxydants des tissus vegetaux sont souvent inactifs ou tres peu actifs a l'etat de repos et ne deviennent actifs qu'en cas de lesion du tissu ou lorsqu'ils sont separes de celui-ci. Lors de la preparation des denrees alimentaires, ce phenomene a pour effet d'accelerer l'oxydation des substrats naturels et de polymeriser les produits, ce qui donne lieu a une decoloration du tissu. Les oxydases de cuivre sont les principaux enzymes qui interviennent comme catalyseurs dans ces reactions. L'activation de l'enzyme entraine en outre une inhibition de la reaction qu'il subit. Une des causes de ce phenomene est la diminution de la

  13. Obtaining of Fibers and granules of carbon for the Immobilization of Enzymes

    International Nuclear Information System (INIS)

    Malagon M, Martha L; Rico R, Yolanda Rico R; Lopez de, Helda A; Caicedo M, Luis Alfonso

    2002-01-01

    Fibers and pellets of carbon were prepared from coal tar. The tar was filtrated and stabilized in a nitrogen atmosphere at 330 degrades Celsius. Extrusion and pellets prepared the fibers by injection on water. Lactase was immobilized by adsorption process. Pellets were better support than fibers, because produced lower pressure drop and upper enzyme retention. Pellets showed the following characteristics: density 2,407 g/cm3, porosity 81,69% and diameter 3 mm

  14. Ethanologenic Enzymes of Zymomonas mobilis

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, Lonnie O' Neal

    1999-03-01

    Zymomonas mobilis is a unique microorganism in being both obligately fermentative and utilizing a Entner-Doudoroff pathway for glycolysis. Glycolytic flux in this organism is readily measured as evolved carbon dioxide, ethanol, or glucose consumed and exceeds 1 {micro}mole glucose/min per mg cell protein. To support this rapid glycolysis, approximately 50% of cytoplasmic protein is devoted to the 13 glycolytic and fermentative enzymes which constitute this central catabolic pathway. Only 1 ATP (net) is produced from each glucose metabolized. During the past grant period, we have completed the characterization of 11 of the 13 glycolytic genes from Z. mobilis together with complementary but separate DOE-fimded research by a former post-dot and collaborator, Dr. Tyrrell Conway. Research funded in my lab by DOE, Division of Energy Biosciences can be divided into three sections: A. Fundamental studies; B. Applied studies and utility; and C. Miscellaneous investigations.

  15. CELLULOSE DEGRADATION BY OXIDATIVE ENZYMES

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  16. Preparation and characterization of controlled-release fertilizers coated with marine polysaccharide derivatives

    Science.gov (United States)

    Wang, Jing; Liu, Song; Qin, Yukun; Chen, Xiaolin; Xing, Rong'e.; Yu, Huahua; Li, Kecheng; Li, Pengcheng

    2017-09-01

    Encapsulation of water-soluble nitrogen fertilizers by membranes can be used to control the release of nutrients to maximize the fertilization effect and reduce environmental pollution. In this research, we formulated a new double-coated controlled-release fertilizer (CRF) by using food-grade microcrystalline wax (MW) and marine polysaccharide derivatives (calcium alginate and chitosan-glutaraldehyde copolymer). The pellets of water-soluble nitrogen fertilizer were coated with the marine polysaccharide derivatives and MW. A convenient and eco-friendly method was used to prepare the CRF. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the morphology and composition of the products. The nitrogen-release properties were determined in water using UV-Vis spectrophotometry. The controlled-release properties of the fertilizer were improved dramatically after coating with MW and the marine polysaccharide derivatives. The results show that the double-coated CRFs can release nitrogen in a controlled manner, have excellent controlled-release features, and meet the European Standard for CRFs.

  17. INDUCTION OF ENZYME COCKTAILS BY LOW COST CARBON SOURCES FOR PRODUCTION OF MONOSACCHARIDE-RICH SYRUPS FROM PLANT MATERIALS

    Directory of Open Access Journals (Sweden)

    Caroline T. Gilleran

    2010-05-01

    Full Text Available The production of cellulases, hemicellulases, and starch-degrading enzymes by the thermophilic aerobic fungus Talaromyces emersonii under liquid state culture on various food wastes was investigated. A comprehensive enzyme screening was conducted, which resulted in the identification of spent tea leaves as a potential substrate for hydrolytic enzyme production. The potent, polysaccharide-degrading enzyme-rich cocktail produced when tea leaves were utilised as sole carbon source was analysed at a protein and mRNA level and shown to exhibit high level production of key cellulose and hemicellulose degrading enzymes. As presented in this paper, the crude enzyme preparation produced after 120 h growth of Talaromyces emersonii on used tea leaves is capable of hydrolysing other lignocellulosic materials into their component monosaccharides, generating high value sugar syrups with a host of industrial applications including conversion to fuels and chemicals.

  18. Pancreatic enzyme replacement therapy for people with cystic fibrosis.

    Science.gov (United States)

    Somaraju, Usha Rani; Solis-Moya, Arturo

    2016-11-23

    Most people with cystic fibrosis (80% to 90%) need pancreatic enzyme replacement therapy to prevent malnutrition. Enzyme preparations need to be taken whenever food is taken, and the dose needs to be adjusted according to the food consumed. A systematic review on the efficacy and safety of pancreatic enzyme replacement therapy is needed to guide clinical practice, as there is variability between centres with respect to assessment of pancreatic function, time of commencing treatment, dose and choice of supplements. This is an updated version of a published review. To evaluate the efficacy and safety of pancreatic enzyme replacement therapy in children and adults with cystic fibrosis and to compare the efficacy and safety of different formulations of this therapy and their appropriateness in different age groups. Also, to compare the effects of pancreatic enzyme replacement therapy in cystic fibrosis according to different diagnostic subgroups (e.g. different ages at introduction of therapy and different categories of pancreatic function). We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 15 July 2016.We also searched an ongoing trials website and the websites of the pharmaceutical companies who manufacture pancreatic enzyme replacements for any additional trials. Most recent search: 22 July 2016. Randomised and quasi-randomised controlled trials in people of any age, with cystic fibrosis and receiving pancreatic enzyme replacement therapy, at any dosage and in any formulation, for a period of not less than four weeks, compared to placebo or other pancreatic enzyme replacement therapy preparations. Two authors independently assessed trials and extracted outcome data. They also assessed the risk of bias of the trials included in the review. One

  19. Enzyme immobilization and biocatalysis of polysiloxanes

    Science.gov (United States)

    Poojari, Yadagiri

    Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

  20. Prediction of Wild-type Enzyme Characteristics

    DEFF Research Database (Denmark)

    Geertz-Hansen, Henrik Marcus

    of biotechnology, including enzyme discovery and characterization. This work presents two articles on sequence-based discovery and functional annotation of enzymes in environmental samples, and two articles on analysis and prediction of enzyme thermostability and cofactor requirements. The first article presents...... a sequence-based approach to discovery of proteolytic enzymes in metagenomes obtained from the Polar oceans. We show that microorganisms living in these extreme environments of constant low temperature harbour genes encoding novel proteolytic enzymes with potential industrial relevance. The second article...... presents a web server for the processing and annotation of functional metagenomics sequencing data, tailored to meet the requirements of non-bioinformaticians. The third article presents analyses of the molecular determinants of enzyme thermostability, and a feature-based prediction method of the melting...

  1. Toward mechanistic classification of enzyme functions.

    Science.gov (United States)

    Almonacid, Daniel E; Babbitt, Patricia C

    2011-06-01

    Classification of enzyme function should be quantitative, computationally accessible, and informed by sequences and structures to enable use of genomic information for functional inference and other applications. Large-scale studies have established that divergently evolved enzymes share conserved elements of structure and common mechanistic steps and that convergently evolved enzymes often converge to similar mechanisms too, suggesting that reaction mechanisms could be used to develop finer-grained functional descriptions than provided by the Enzyme Commission (EC) system currently in use. Here we describe how evolution informs these structure-function mappings and review the databases that store mechanisms of enzyme reactions along with recent developments to measure ligand and mechanistic similarities. Together, these provide a foundation for new classifications of enzyme function. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. How Do Enzymes 'Meet' Nanoparticles and Nanomaterials?

    Science.gov (United States)

    Chen, Ming; Zeng, Guangming; Xu, Piao; Lai, Cui; Tang, Lin

    2017-11-01

    Enzymes are fundamental biological catalysts responsible for biological regulation and metabolism. The opportunity for enzymes to 'meet' nanoparticles and nanomaterials is rapidly increasing due to growing demands for applications in nanomaterial design, environmental monitoring, biochemical engineering, and biomedicine. Therefore, understanding the nature of nanomaterial-enzyme interactions is becoming important. Since 2014, enzymes have been used to modify, degrade, or make nanoparticles/nanomaterials, while numerous nanoparticles/nanomaterials have been used as materials for enzymatic immobilization and biosensors and as enzyme mimicry. Among the various nanoparticles and nanomaterials, metal nanoparticles and carbon nanomaterials have received extensive attention due to their fascinating properties. This review provides an overview about how enzymes meet nanoparticles and nanomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Production of Enzymes from Marine Actinobacteria.

    Science.gov (United States)

    Zhao, X Q; Xu, X N; Chen, L Y

    Marine actinobacteria are well recognized for their capabilities to produce valuable natural products, which have great potential for applications in medical, agricultural, and fine chemical industries. In addition to producing unique enzymes responsible for biosynthesis of natural products, many marine actinobacteria also produce hydrolytic enzymes which are able to degrade various biopolymers, such as cellulose, xylan, and chitin. These enzymes are important to produce biofuels and biochemicals of interest from renewable biomass. In this chapter, the recent reports of novel enzymes produced by marine actinobacteria are reviewed, and advanced technologies that can be applied to search for novel marine enzymes as well as for improved enzyme production by marine actinobacteria are summarized, which include ribosome engineering, genome mining, as well as synthetic biology studies. © 2016 Elsevier Inc. All rights reserved.

  4. Evaluation of pressure tuning of enzymes

    DEFF Research Database (Denmark)

    Naghshineh, Mahsa

    and high energy consumption. Therefore, searching for an environmentally friendly method of pectin extraction is a task for science and industry. Employment of hydrolytic enzymes may represent a green approach to obtain intact pectin polymer. However, the low stability/activity of enzymes, and low polymer...... yield of enzymatic extraction limits the application of enzyme in pectin production. There is evidence that emerging technology of high hydrostatic pressure processing can result in stabilization and activation of some enzymes. Therefore, the use of high hydrostatic pressure in combination with enzyme...... (cellulase/xylanase: 50/0, 50/25, 50/50, 25/50, and 0/50 U/g lime peel) at ambient pressure, 100 and 200 MPa were used to extract pectin from dried lime peel waste. It was found that pressure level, type and concentration of enzyme significantly influenced pectin yield and degree of esterification (DE...

  5. Enzyme-Catalyzed Synthesis of Saccharide Acrylate Monomers from Nonedible Biomass

    NARCIS (Netherlands)

    Kloosterman, Wouter M. J.; Brouwer, Sander; Loos, Katja

    Various cellulase preparations were found to catalyze the transglycosidation between cotton linters and 2-hydroxyethyl acrylate. The conversion and enzyme activity were found to be optimal in reaction mixtures that contained 5 vol% of the acrylate. The structures of the products were revealed by

  6. Bacteria and digestive enzymes in the alimentary tract of the giant ...

    African Journals Online (AJOL)

    A study was carried out to investigate the bacteria flora in the gut of the Giant African Land Snails (GALS), Archarchatina marginata and Achatina achatina. Microflora cultures from snail gut contents were prepared to isolate and identify microorganisms within the snail digestive tract. Enzyme assays were carried out on a few ...

  7. Effect of enzyme treatment on pea starch physicomechanical properties of biofilms

    OpenAIRE

    A. Sh. Zakirova; T. N. Manahova; A. V. Kanarskiy; Z. A. Kanarskaya

    2013-01-01

    The regularities of change in physical and mechanical properties of biofilms based on pea starch treated with pullulanase enzyme preparation were obtained. The possibility of formation of linear pea starch amylopectin polymers, which contribute to improvement of the mechanical and rheological properties of biofilms was identified.

  8. Effect of enzyme treatment on pea starch physicomechanical properties of biofilms

    Directory of Open Access Journals (Sweden)

    A. Sh. Zakirova

    2013-01-01

    Full Text Available The regularities of change in physical and mechanical properties of biofilms based on pea starch treated with pullulanase enzyme preparation were obtained. The possibility of formation of linear pea starch amylopectin polymers, which contribute to improvement of the mechanical and rheological properties of biofilms was identified.

  9. Hydrioxylation of sesquiterpenes by enzymes from chicory (Cichorium intybus L.) roots

    NARCIS (Netherlands)

    Kraker, de J.W.; Schurink, M.; Franssen, M.C.R.; König, W.A.; Groot, de Æ.; Bouwmeester, H.J.

    2003-01-01

    A microsomal enzyme preparation of chicory roots catalyses the hydroxylation of various sesquiterpene olefins in the presence of NADPH. Most of these hydroxylations take place at an isopropenyl or isopropylidene group. The number of products obtained from any of the substrates is confined to one or,

  10. Correspondence between radioactive and functional methods in the quality control of DNA restriction and modifying enzymes

    DEFF Research Database (Denmark)

    Trujillo, L E; Pupo, E; Miranda, F

    1996-01-01

    We evaluated the use of two radiolabeled lambda DNA/Hpa II substrates to detect 5'-->3', 3'-->5' single and double stranded DNA dependent exonuclease and phosphatase activities found as contaminants in restriction and modifying enzyme preparations. Looking for the meaning of the radioactive assay...

  11. Star block-copolymers: Enzyme-inspired catalysts for oxidation of alcohols in water

    KAUST Repository

    Mugemana, Clement

    2014-01-01

    A number of fluorous amphiphilic star block-copolymers containing a tris(benzyltriazolylmethyl)amine motif have been prepared. These polymers assembled into well-defined nanostructures in water, and their mode of assembly could be controlled by changing the composition of the polymer. The polymers were used for enzyme-inspired catalysis of alcohol oxidation. This journal is © the Partner Organisations 2014.

  12. Production of native-starch-degrading enzymes by a Bacillus firmus/lentus strain

    NARCIS (Netherlands)

    Wijbenga, Dirk-Jan; Beldman, Gerrit; Veen, Anko; Binnema, Doede

    1991-01-01

    A bacterium belonging to the Bacillus firmus/lentus-complex and capable of growth on native potato starch was isolated from sludge of a pilot plant unit for potato-starch production. Utilization of a crude enzyme preparation obtained from the culture fluid after growth of the microorganism on native

  13. Enzyme Enzyme activities in relation to sugar accumulation in tomato

    International Nuclear Information System (INIS)

    Alam, M.J.; Rahman, M.H.; Mamun, M.A.; Islam, K.

    2006-01-01

    Enzyme activities in tomato juice of five different varieties viz. Ratan, Marglove, BARI-1, BARI-5 and BARI-6, in relation to sugar accumulation were investigated at different maturity stages. The highest amount of invertase and beta-galactosidase was found in Marglove and the lowest in BARI- 6 at all maturity stages. Total soluble sugar and sucrose contents were highest in BARI-1 and lowest in BARI-6. The activity of amylase was maximum in Ratan and minimum in Marglove. Protease activity was highest in Ratan and lowest in BARI-6. BARI-1 contained the highest cellulase activity and the lowest in BARI-5. The amount of total soluble sugar and sucrose increased moderately from premature to ripe stage. The activities of amylase and cellulase increased up to the mature stage and then decreased drastically in the ripe stage. The activities of invertase and protease increased sharply from the premature to the ripe stage while the beta-galactosidase activity decreased remarkably. No detectable amount of reducing sugar was present in the premature stage in all cultivars of tomato but increased thereafter upto the ripe stage. The highest reducing sugar was present in BARI-5 in all of the maturity stages. (author)

  14. Analytical systems as a basis for immobilized enzymes. 3. Use of a glucose enzyme electrode to determine carbohydrates in biological solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kulys, J; Pesliakiene, M

    1981-01-01

    A method is described for determination of glucose, sucrose, and lactose in biological solutions using a glucose enzyme electrode characterized by high sensitivity and selectivity. The enzyme membrane (15 nm thick) is prepared from glucose oxidase isolated from Penicillium vitale. Glucose is determined in one minute (using static currents) or in 12 s (using registered current in a kinetic regime). Phosphate buffer (5-10 mM) is the only reagent required for analysis. Determination of sucrose and lactose require prior hydrolysis with 17.8% HCl at 70 degrees Celcius for O.5 and lO.7 minutes, respectively.

  15. [Advances on enzymes and enzyme inhibitors research based on microfluidic devices].

    Science.gov (United States)

    Hou, Feng-Hua; Ye, Jian-Qing; Chen, Zuan-Guang; Cheng, Zhi-Yi

    2010-06-01

    With the continuous development in microfluidic fabrication technology, microfluidic analysis has evolved from a concept to one of research frontiers in last twenty years. The research of enzymes and enzyme inhibitors based on microfluidic devices has also made great progress. Microfluidic technology improved greatly the analytical performance of the research of enzymes and enzyme inhibitors by reducing the consumption of reagents, decreasing the analysis time, and developing automation. This review focuses on the development and classification of enzymes and enzyme inhibitors research based on microfluidic devices.

  16. Zymography methods for visualizing hydrolytic enzymes.

    Science.gov (United States)

    Vandooren, Jennifer; Geurts, Nathalie; Martens, Erik; Van den Steen, Philippe E; Opdenakker, Ghislain

    2013-03-01

    Zymography is a technique for studying hydrolytic enzymes on the basis of substrate degradation. It is a powerful, but often misinterpreted, tool yielding information on potential hydrolytic activities, enzyme forms and the locations of active enzymes. In this Review, zymography techniques are compared in terms of advantages, limitations and interpretations. With in gel zymography, enzyme forms are visualized according to their molecular weights. Proteolytic activities are localized in tissue sections with in situ zymography. In vivo zymography can pinpoint proteolytic activity to sites in an intact organism. Future development of novel substrate probes and improvement in detection and imaging methods will increase the applicability of zymography for (reverse) degradomics studies.

  17. Detoxification enzymes activities in deltamethrin and bendiocarb ...

    African Journals Online (AJOL)

    Detoxification enzymes activities in deltamethrin and bendiocarb resistant and susceptible malarial vectors ( Anopheles gambiae ) breeding in Bichi agricultural and residential sites, Kano state, Nigeria.

  18. Escherichia coli photoreactivating enzyme: purification and properties

    International Nuclear Information System (INIS)

    Snapka, R.M.; Sutherland, B.M.

    1980-01-01

    Researchers have purified large quantities of Escherichia coli photoreactivating enzyme to apparent homogeneity and have studied its physical and chemical properties. The enzyme has a molecular weight of 36,800 and a S/sub 20,w/ 0 of 3.72 S. Amino acid analysis revealed an apparent absence of tryptophan, a low content of aromatic residues, and the presence of no unusual amino acids. The N terminus is arginine. The purified enzyme contained up to 13% carbohydrate by weight. The carbohydrate was composed of mannose, galactose, glucose, and N-acetylglucosamine. The enzyme is also associated with RNA containing uracil, adenine, guanine, and cytosine with no unusual bases detected

  19. Thermometric enzyme linked immunosorbent assay: TELISA.

    Science.gov (United States)

    Mattiasson, B; Borrebaeck, C; Sanfridson, B; Mosbach, K

    1977-08-11

    A new method, thermometric enzyme linked immunosorbent assay (TELISA), for the assay of endogenous and exogenous compounds in biological fluids is described. It is based on the previously described enzyme linked immunosorbent assay technique, ELISA, but utilizes enzymic heat formation which is measured in an enzyme thermistor unit. In the model system studied determination of human serum albumin down to a concentration of 10(-10) M (5 ng/ml) was achieved, with both normal and catalase labelled human serum albumin competing for the binding sites on the immunosorbent, which was rabbit antihuman serum albumin immobilized onto Sepharose CL-4B.

  20. The mechanisms of Excited states in enzymes

    DEFF Research Database (Denmark)

    Petersen, Frederic Nicolas Rønne; Bohr, Henrik

    2010-01-01

    Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes.......Enzyme catalysis is studied on the basis of excited state processes, which are of electronic, vibrational and thermal nature. The ways of achieving the excited state, such as photo-absorption and ligand binding, are discussed and exemplified by various cases of enzymes....

  1. Adsorption of cellulase on cellulolytic enzyme lignin from lodgepole pine.

    Science.gov (United States)

    Tu, Maobing; Pan, Xuejun; Saddler, Jack N

    2009-09-09

    Enzymatic hydrolysis of lignocellulosic materials is significantly affected by cellulase adsorption onto the lignocellulosic substrates and lignin. The presence of lignin plays an important role in lignocellulosic hydrolysis and enzyme recycling. Three cellulase preparations (Celluclast, Spezyme CP, and MSUBC) were evaluated to determine their adsorption onto cellulolytic enzyme lignin (CEL) from steam-exploded Lodgepole pine (SELP) and ethanol (organosolv)-pretreated Lodgepole pine (EPLP). The adsorption affinity of cellulase (Celluclast) onto isolated lignin (CEL-EPLP and CEL-SELP) was slightly higher than that from corresponding EPLP and SELP substrates on the basis of the Langmuir constants. Effects of temperature, ionic strength, and surfactant on cellulase adsorption onto isolated lignin were also explored in this study. Thermodynamic analysis of enzyme adsorption onto isolated lignin (Gibbs free energy change DeltaG(0) approximately -30 kJ/mol) indicated this adsorption was a spontaneous process. The addition of surfactant (0.2% w/v) could reduce the adsorption of cellulase onto CEL-SELP by 60%. Two types of adsorption isotherm were compared for cellulase adsorption onto isolated lignin. A Langmuir adsorption isotherm showed better fit for the experimental data than a Freundlich adsorption isotherm.

  2. Effect of peat extract on the hydrolytic enzymes of Phanerochaete chrysosporium

    Energy Technology Data Exchange (ETDEWEB)

    Nawaz, M; Gunasekaran, M

    1988-08-01

    Peat, a partially decomposed plant material rich in minerals and lignocellulose was tested as a substrate for the growth and production of hydrolytic enzymes viz. cellulase, cellobiase and xylanase in Phanerochaete chrysosporium. Three types of peat extracts such as cold, hot water and autoclaved were prepared and tested. Among them, autoclaved extract supported the maximal growth. The intracellular enzyme activities peaked on the fifth day after inoculation irrespective of the media and enzyme tested. Addition of cellobiose and lactose in the medium induced the production of cellulase, xylanase and to a lesser extent cellobiase. Addition of glucose and sucrose to the media resulted in the suppression of all the extracellular enzymes tested. 18 refs., 5 figs.

  3. Stabilization of oil-in-water emulsions by enzyme catalyzed oxidative gelation of sugar beet pectin

    DEFF Research Database (Denmark)

    Abang Zaidel, Dayang Norulfairuz; Chronakis, Ioannis S.; Meyer, Anne S.

    2013-01-01

    Enzyme catalyzed oxidative cross-linking of feruloyl groups can promote gelation of sugar beet pectin (SBP). It is uncertain how the enzyme kinetics of this cross-linking reaction are affected in emulsion systems and whether the gelation affects emulsion stability. In this study, SBP (2.5% w...... larger average particle sizes than the emulsions in which the SBP was homogenized into the emulsion system during emulsion preparation (referred as Mix B). Mix B type emulsions were stable. Enzyme catalyzed oxidative gelation of SBP helped stabilize the emulsions in Mix A. The kinetics of the enzyme...... catalyzed oxidative gelation of SBP was evaluated by small angle oscillatory measurements for horseradish peroxidase (HRP) (EC 1.11.1.7) and laccase (EC 1.10.3.2) catalysis, respectively. HRP catalyzed gelation rates, determined from the slopes of the increase of elastic modulus (G0) with time, were higher...

  4. Enzymatic hydrolysis of steam-pretreated lignocellulosic materials with Trichoderma atroviride enzymes produced in-house

    Directory of Open Access Journals (Sweden)

    Macrelli Stefano

    2009-07-01

    Full Text Available Abstract Background Improvement of the process of cellulase production and development of more efficient lignocellulose-degrading enzymes are necessary in order to reduce the cost of enzymes required in the biomass-to-bioethanol process. Results Lignocellulolytic enzyme complexes were produced by the mutant Trichoderma atroviride TUB F-1663 on three different steam-pretreated lignocellulosic substrates, namely spruce, wheat straw and sugarcane bagasse. Filter paper activities of the enzymes produced on the three materials were very similar, while β-glucosidase and hemicellulase activities were more dependent on the nature of the substrate. Hydrolysis of the enzyme preparations investigated produced similar glucose yields. However, the enzymes produced in-house proved to degrade the xylan and the xylose oligomers less efficiently than a commercial mixture of cellulase and β-glucosidase. Furthermore, accumulation of xylose oligomers was observed when the TUB F-1663 supernatants were applied to xylan-containing substrates, probably due to the low β-xylosidase activity of the enzymes. The efficiency of the enzymes produced in-house was enhanced by supplementation with extra commercial β-glucosidase and β-xylosidase. When the hydrolytic capacities of various mixtures of a commercial cellulase and a T. atroviride supernatant produced in the lab were investigated at the same enzyme loading, the glucose yield appeared to be correlated with the β-glucosidase activity, while the xylose yield seemed to be correlated with the β-xylosidase level in the mixtures. Conclusion Enzyme supernatants produced by the mutant T. atroviride TUB F-1663 on various pretreated lignocellulosic substrates have good filter paper activity values combined with high levels of β-glucosidase activities, leading to cellulose conversion in the enzymatic hydrolysis that is as efficient as with a commercial cellulase mixture. On the other hand, in order to achieve good xylan

  5. Evaluation of the organophosphorus hydrolase enzyme activity in creams and investigation of its stability

    Directory of Open Access Journals (Sweden)

    Mariye Rajaie

    2016-06-01

    Full Text Available The main purpose of this project is investigation of the organophosphorus hydrolase (OPH enzyme activity in water in oil (w/o and oil in water (o/w creams and investigation of the OPH enzyme stability in formulated creams. OPH enzyme was extracted and purified from strain flavobacterium. The w/o and o/w creams were prepared using different formulations. In order to achieve an emulsion with maximum stability, appropriate percentage of the cream components was selected by studying different formulations and the physical and chemical stability of the produced cream were considered. 5Uenzyme/90gcream enzyme was used for each formulation. To measure the enzyme activity in creams, extraction method was used and enzyme activity was determined based on parathion hydrolysis. The thermal stability of OPH in both types of w/o and o/w creams was studied at 4 and 30  °C for various time periods. The average enzyme activity was about 0.0065 U/gcream and 0.018 U/gcream for w/o and o/w creams respectivly. According to the results, the relative activity at 4 °C was reduced to 50% after 26 and 45 days in w/o and o/w creams, respectivly. The results showed that the OPH enzyme activity in o/w cream was 2.6 times more than that of w/o cream, because of the higher hydrophobicity of o/w cream compared to w/o. The OPH enzyme stability in o/w cream was greater in comparison to w/o cream. The OPH enzyme was active for nearly 2 months on o/w creams at 4 °C .

  6. Pancreatic enzyme replacement therapy for pancreatic exocrine insufficiency in the 21(st) century.

    Science.gov (United States)

    Trang, Tony; Chan, Johanna; Graham, David Y

    2014-09-07

    Restitution of normal fat absorption in exocrine pancreatic insufficiency remains an elusive goal. Although many patients achieve satisfactory clinical results with enzyme therapy, few experience normalization of fat absorption, and many, if not most, will require individualized therapy. Increasing the quantity of lipase administered rarely eliminates steatorrhea but increases the cost of therapy. Enteric coated enzyme microbead formulations tend to separate from nutrients in the stomach precluding coordinated emptying of enzymes and nutrients. Unprotected enzymes mix well and empty with nutrients but are inactivated at pH 4 or below. We describe approaches for improving the results of enzyme therapy including changing to, or adding, a different product, adding non-enteric coated enzymes, (e.g., giving unprotected enzymes at the start of the meal and acid-protected formulations later), use of antisecretory drugs and/or antacids, and changing the timing of enzyme administration. Because considerable lipid is emptied in the first postprandial hour, it is prudent to start therapy with enteric coated microbead prior to the meal so that some enzymes are available during that first hour. Patients with hyperacidity may benefit from adjuvant antisecretory therapy to reduce the duodenal acid load and possibly also sodium bicarbonate to prevent duodenal acidity. Comparative studies of clinical effectiveness of different formulations as well as the characteristics of dispersion, emptying, and dissolution of enteric-coated microspheres of different diameter and density are needed; many such studies have been completed but not yet made public. We discuss the history of pancreatic enzyme therapy and describe current use of modern preparations, approaches to overcoming unsatisfactory clinical responses, as well as studies needed to be able to provide reliably effective therapy.

  7. Pancreatic enzyme replacement therapy for pancreatic exocrine insufficiency in the 21st century

    Science.gov (United States)

    Trang, Tony; Chan, Johanna; Graham, David Y

    2014-01-01

    Restitution of normal fat absorption in exocrine pancreatic insufficiency remains an elusive goal. Although many patients achieve satisfactory clinical results with enzyme therapy, few experience normalization of fat absorption, and many, if not most, will require individualized therapy. Increasing the quantity of lipase administered rarely eliminates steatorrhea but increases the cost of therapy. Enteric coated enzyme microbead formulations tend to separate from nutrients in the stomach precluding coordinated emptying of enzymes and nutrients. Unprotected enzymes mix well and empty with nutrients but are inactivated at pH 4 or below. We describe approaches for improving the results of enzyme therapy including changing to, or adding, a different product, adding non-enteric coated enzymes, (e.g., giving unprotected enzymes at the start of the meal and acid-protected formulations later), use of antisecretory drugs and/or antacids, and changing the timing of enzyme administration. Because considerable lipid is emptied in the first postprandial hour, it is prudent to start therapy with enteric coated microbead prior to the meal so that some enzymes are available during that first hour. Patients with hyperacidity may benefit from adjuvant antisecretory therapy to reduce the duodenal acid load and possibly also sodium bicarbonate to prevent duodenal acidity. Comparative studies of clinical effectiveness of different formulations as well as the characteristics of dispersion, emptying, and dissolution of enteric-coated microspheres of different diameter and density are needed; many such studies have been completed but not yet made public. We discuss the history of pancreatic enzyme therapy and describe current use of modern preparations, approaches to overcoming unsatisfactory clinical responses, as well as studies needed to be able to provide reliably effective therapy. PMID:25206255

  8. Spectroscopic studies of copper enzymes

    International Nuclear Information System (INIS)

    Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

    1986-01-01

    Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present

  9. Effects of pectolytic enzyme treatment and microfiltration on antioxidant components of elderberry juice

    Directory of Open Access Journals (Sweden)

    Furulyás D.

    2017-10-01

    Full Text Available In this study, pectolytic enzymes (Pectinex BE XXL, Trenolin Rot, and Fructozym P were investigated for their influence on phenolic, anthocyanin content, and antioxidant activities of elderberry (Sambucus nigra L. pulps during juice processing. Prior to pressing the berries, three different enzymes were added to pulps in order to evaluate the effect of different pectolytic enzyme treatments on the valuable components of elderberry juice. Control sample was prepared without enzyme. After treatment, squeezing, and clarification steps, microfiltration was carried out with ceramic membrane. The effect of this technology on the antioxidant capacity, total polyphenol content, and total anthocyanin content of the clarified elderberry juices has been evaluated in permeate and retentate samples, and membrane retention was calculated. Significantly lower antioxidant capacity was detected in the case of control sample than that obtained using enzyme-treated juices. Retention of antioxidant content on the microfiltration membrane was greatly reduced by using the enzymes. Higher valuable component yield was obtained using Fructozym P enzyme compared with Pectinex BE XXL used in industry.

  10. EFFECT OF MARINATION WITH PROTEOLYTIC ENZYMES ON QUALITY OF BEEF MUSCLE

    Directory of Open Access Journals (Sweden)

    Daniela Istrati

    2012-03-01

    Full Text Available During storage and thermal treatment meat suffers a number of biochemical and physical-chemical changes in the substrate protein, changes that take place with varying intensity depending on the method of preservation utilized and temperature of thermal treatment applied. Application of different treatments aimed to influence the proteolytic activity as is the case of enzymatic tenderization of beef.Improving the meat tenderness with proteolytic enzymes is promising, but current legislation restricting the use of proteolytic enzymes from bacterial origin and recommended tenderizers salts containing papain, ficin and bromelain. Recent research revealed that meat marinating before grilling results in a reduction of heterocyclic amine content after thermal treatment. Also, the addition of fruit pulp, garlic or other spices contributes to decreased production of heterocyclic amines because of their antioxidant activity. In the present study was aimed influence of exogenous proteolytic enzymes on adult beef tenderness. To increase the tenderness of adult beef were used exogenous enzymes preparations (papain and bromelain and natural sources of enzymes using pineapple and papaya fruit. It was intended to establish the correlation between enzymatic activity of enzymes used in the study, the processing technology and changes in the physical-chemical and biochemical characteristics that occur during storage in refrigerated conditions (evolution of the rigidity index and water holding capacity, cooking losses and cooking yield of the samples injected/marinated with enzymes.

  11. Bacterial whole-cell biocatalysts by surface display of enzymes: toward industrial application.

    Science.gov (United States)

    Schüürmann, Jan; Quehl, Paul; Festel, Gunter; Jose, Joachim

    2014-10-01

    Despite the first report on the bacterial display of a recombinant peptide appeared almost 30 years ago, industrial application of cells with surface-displayed enzymes is still limited. To display an enzyme on the surface of a living cell bears several advantages. First of all, neither the substrate nor the product of the enzymatic reaction needs to cross a membrane barrier. Second, the enzyme being linked to the cell can be separated from the reaction mixture and hence the product by simple centrifugation. Transfer to a new substrate preparation results in multiple cycles of enzymatic conversion. Finally, the anchoring in a matrix, in this case, the cell envelope stabilizes the enzyme and makes it less accessible to proteolytic degradation and material adsorption resulting in continuous higher activities. These advantages in common need to balance some disadvantages before this application can be taken into account for industrial processes, e.g., the exclusion of the enzyme from the cellular metabolome and hence from redox factors or other co-factors that need to be supplied. Therefore, this digest describes the different systems in Gram-positive and Gram-negative bacteria that have been used for the surface display of enzymes so far and focuses on examples among these which are suitable for industrial purposes or for the production of valuable resources, not least in order to encourage a broader application of whole-cell biocatalysts with surface-displayed enzymes.

  12. Ultrasonic treatment of Viscozyme Cassava C preparation for improving cellulase activity

    Science.gov (United States)

    Tra, Tran Thi Thu; Vu, Huynh Minh; Man, Le Van Viet

    2017-09-01

    In this study, the effects of ultrasonic treatment on the cellulolytic activity of Viscozyme Cassava C preparation were investigated. The biocatalyst was treated with ultrasound at different enzyme concentrations (from 0.02 to 19.50 mg protein/mL), ultrasonic powers (from 0 to 12 W/mL) and times (from 0 to 120 seconds). The highest cellulase activity was achieved when the enzyme preparation was ultrasonicated at 7.3 W/mL for 40 sec, under which the cellulase activity increased by 18.1% over the control. The optimal pH and temperature of the sonicated and unsonicated biocatalysts were statistically similar. However, the half-life value of the sonicated preparation at 4 °C was 24.5% higher than that of the unsonicated preparation. This result indicated that ultrasonic treatment of the enzyme preparation could reduce its amount used in biocatalysis.

  13. Direct Electron Transfer of Enzymes in a Biologically Assembled Conductive Nanomesh Enzyme Platform.

    Science.gov (United States)

    Lee, Seung-Woo; Lee, Ki-Young; Song, Yong-Won; Choi, Won Kook; Chang, Joonyeon; Yi, Hyunjung

    2016-02-24

    Nondestructive assembly of a nanostructured enzyme platform is developed in combination of the specific biomolecular attraction and electrostatic coupling for highly efficient direct electron transfer (DET) of enzymes with unprecedented applicability and versatility. The biologically assembled conductive nanomesh enzyme platform enables DET-based flexible integrated biosensors and DET of eight different enzyme with various catalytic activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. El ensayo inmunoenzimatico en microgotas sobre nitrocelulosa (Dot-ELISA en el diagnostico de la enfermedad de Chagas: I. Estudio comparativo de dos preparaciones antigenicos de Trypanosoma cruzi The Dot-Enzyme linked immunosorbent assay (Dot-ELISA in the diagnosis of Chagas-disease: I. Comparative study of two antigenic preparations of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Rosa M. de Hubsch

    1988-09-01

    Full Text Available Se estudia el Ensayo Inmunoenzimático en Microgotas sobre Nitrocelulosa (Dot-ELISAcomparando dos preparados antigénicos de formas epimastigotas de cultivo de T. cruzi: 1 la fracción citoplasmática (antígeno citoplasmático y 2 el parásito total fijado previamente con formaldehido (antígeno integral. Se usaron sueros de: 95 pacientes chagásicos con serología convencional positiva, cardiopatía crónica y algunos con xenodiagnóstico positivo; 42 personas sanas y 32 con miocardipatía crónica con serología negativa y 74 pacientes con diferentes patologías incluyendo: sífilis, toxoplasmosis, lupus eritematoso diseminado, con factor reumatoide, leishmaniasis visceral, y leishmaniasis cutánea. Definidos los títulos diagnósticos (cut-off de 1:512 con antígeno citoplasmático y de 1: 128 con antígeno integral, la especificidad fue 96% para el primero y de 100% para el segundo; mientras que la sensibilidad fue de 100% para ambas. En el estudio comparativo con las pruebas serológicas convencionales examinando 147 sueros tomados de personas referidas al laboratório, Dot-ELISA con antígeno citoplasmático presentó índices deco-positividad de 1,0, co-negatividad de 0,989 y eficiencia 0,993. Dot-ELIS con antígeno integral dió 1,0, 0,979 y 0,986 respectivamente. De acuerdo con esta evaluación, la técnica Dot-ELISA con antígeno integral se presenta como una alternativa práctica para el diagnóstico serológico de la enfermedad de Chagas.Using the Dot-ELISA technique, two antigenic preparations of Trypanosoma cruzi epimastigote forms have been compared for the diagnosis of Chagas' disease: (1 The citoplasmic fraction (citoplasmic antigen and (2 whole fixed epimastigotes (integral antigen. There was been used sera from 95 chagasic patients with chronic cadiomyopathy, positive conventional serology and either positive or negative xenodiagnosis; 74 subjects with negative conventional serology, and either clinically normal or presenting

  15. Enzyme Activity Experiments Using a Simple Spectrophotometer

    Science.gov (United States)

    Hurlbut, Jeffrey A.; And Others

    1977-01-01

    Experimental procedures for studying enzyme activity using a Spectronic 20 spectrophotometer are described. The experiments demonstrate the effect of pH, temperature, and inhibitors on enzyme activity and allow the determination of Km, Vmax, and Kcat. These procedures are designed for teaching large lower-level biochemistry classes. (MR)

  16. The use of enzymes for beer brewing

    NARCIS (Netherlands)

    Donkelaar, van Laura H.G.; Mostert, Joost; Zisopoulos, Filippos K.; Boom, Remko M.; Goot, van der Atze Jan

    2016-01-01

    The exergetic performance of beer produced by the conventional malting and brewing process is compared with that of beer produced using an enzyme-assisted process. The aim is to estimate if the use of an exogenous enzyme formulation reduces the environmental impact of the overall brewing process.

  17. Lignocellulose biotechnology: issues of bioconversion and enzyme ...

    African Journals Online (AJOL)

    Lignocellulose biotechnology: issues of bioconversion and enzyme production. ... and secondly to highlight some of the modern approaches which potentially could be used to tackle one of the major impediments, namely high enzyme cost, to speed-up the extensive commercialisation of the lignocellulose bioprocessing.

  18. Illustrating Enzyme Inhibition Using Gibbs Energy Profiles

    Science.gov (United States)

    Bearne, Stephen L.

    2012-01-01

    Gibbs energy profiles have great utility as teaching and learning tools because they present students with a visual representation of the energy changes that occur during enzyme catalysis. Unfortunately, most textbooks divorce discussions of traditional kinetic topics, such as enzyme inhibition, from discussions of these same topics in terms of…

  19. Enzyme Catalysis and the Gibbs Energy

    Science.gov (United States)

    Ault, Addison

    2009-01-01

    Gibbs-energy profiles are often introduced during the first semester of organic chemistry, but are less often presented in connection with enzyme-catalyzed reactions. In this article I show how the Gibbs-energy profile corresponds to the characteristic kinetics of a simple enzyme-catalyzed reaction. (Contains 1 figure and 1 note.)

  20. Enzyme Engineering for In Situ Immobilization.

    Science.gov (United States)

    Rehm, Fabian B H; Chen, Shuxiong; Rehm, Bernd H A

    2016-10-14

    Enzymes are used as biocatalysts in a vast range of industrial applications. Immobilization of enzymes to solid supports or their self-assembly into insoluble particles enhances their applicability by strongly improving properties such as stability in changing environments, re-usability and applicability in continuous biocatalytic processes. The possibility of co-immobilizing various functionally related enzymes involved in multistep synthesis, conversion or degradation reactions enables the design of multifunctional biocatalyst with enhanced performance compared to their soluble counterparts. This review provides a brief overview of up-to-date in vitro immobilization strategies while focusing on recent advances in enzyme engineering towards in situ self-assembly into insoluble particles. In situ self-assembly approaches include the bioengineering of bacteria to abundantly form enzymatically active inclusion bodies such as enzyme inclusions or enzyme-coated polyhydroxyalkanoate granules. These one-step production strategies for immobilized enzymes avoid prefabrication of the carrier as well as chemical cross-linking or attachment to a support material while the controlled oriented display strongly enhances the fraction of accessible catalytic sites and hence functional enzymes.

  1. Utilization of enzyme supplemented Telfairia occidentalis stalk ...

    African Journals Online (AJOL)

    An eight (8) week feeding trial was carried out to assess the use of enzyme natuzyme supplemented Telfairia occidentalis stalk extract as growth inducer in the practical diet for Oreochromis niloticus fingerlings. Five isonitrogenous (35% crude protein) diets at 0 ml of stalk extract and enzyme (TRT 1), 15 ml (TRT 2) and 30 ...

  2. Bacterial Enzymes and Antibiotic Resistance- Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-25

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β-lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes.

  3. Application of radiopolymerization for immobilization of enzymes

    International Nuclear Information System (INIS)

    Higa, O.Z.; Mastro, N.L. del; Castagnet, A.C.G.

    1986-01-01

    Hydrophilic glass-forming monomers were used in an application of irradiation technology for the immobilization of cellulase and cellobiase. Experiments to observe the effect of additives such as silicates and polyethylene glycol in the enzyme entrapment are reported on. In all cases, enzymatic activity was maintained for more than fifteen batch enzyme reactions. (Author) [pt

  4. Enzyme-Catalyzed Transetherification of Alkoxysilanes

    Directory of Open Access Journals (Sweden)

    Peter G. Taylor

    2013-01-01

    Full Text Available We report the first evidence of an enzyme-catalyzed transetherification of model alkoxysilanes. During an extensive enzymatic screening in the search for new biocatalysts for silicon-oxygen bond formation, we found that certain enzymes promoted the transetherification of alkoxysilanes when tert-butanol or 1-octanol were used as the reaction solvents.

  5. Biocatalytic material comprising multilayer enzyme coated fiber

    Science.gov (United States)

    Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

    2009-11-03

    The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

  6. Loop 7 of E2 enzymes

    DEFF Research Database (Denmark)

    Papaleo, Elena; Casiraghi, Nicola; Arrigoni, Alberto

    2012-01-01

    The ubiquitin (Ub) system controls almost every aspect of eukaryotic cell biology. Protein ubiquitination depends on the sequential action of three classes of enzymes (E1, E2 and E3). E2 Ub-conjugating enzymes have a central role in the ubiquitination pathway, interacting with both E1 and E3...

  7. Enzyme adsorption at solid-liquid interfaces

    NARCIS (Netherlands)

    Duinhoven, S.

    1992-01-01

    Enzymes are proteins with the capacity of catalysing various reactions. Nowadays two types of enzymes, proteases and lipases, are available for use in detergent formulations for household and industrial laundry washing. Proteases are capable of catalysing the hydrolysis of proteins while

  8. [Potentialization of antibiotics by lytic enzymes].

    Science.gov (United States)

    Brisou, J; Babin, P; Babin, R

    1975-01-01

    Few lytic enzymes, specially papaine and lysozyme, acting on the membrane and cell wall structures facilitate effects of bacitracine, streptomycine and other antibiotics. Streptomycino resistant strains became sensibles to this antibiotic after contact with papaine and lysozyme. The results of tests in physiological suspensions concern only the lytic activity of enzymes. The results on nutrient medium concern together lytic, and antibiotic activities.

  9. Cytomegalovirus neutralization by hyperimmune and standard intravenous immunoglobulin preparations.

    Science.gov (United States)

    Planitzer, Christina B; Saemann, Marcus D; Gajek, Hartwig; Farcet, Maria R; Kreil, Thomas R

    2011-08-15

    Cytomegalovirus (CMV) remains one of the most important pathogens after transplantation, potentially leading to CMV disease, allograft dysfunction, acute, and chronic rejection and opportunistic infections. Immunoglobulin G (IgG) preparations with high antibody titers against CMV are a valuable adjunctive prevention and treatment option for clinicians and apart from standard intravenous immunoglobulin (IVIG), CMV hyperimmune preparations are available. The CMV antibody titer of these preparations is typically determined by Enzyme-linked immunosorbent assay (ELISA), also used for the selection of high titer plasma donors for the production of the CMV Hyperimmune product. However, CMV ELISA titers do not necessarily correlate with CMV antibody function which is determined by virus neutralization tests. CMV antibody titers were determined by both ELISA and virus neutralization assay and the IgG subclass distribution was compared between a CMV hyperimmune licensed in Europe and standard IVIG preparations. Although the expected high CMV IgG ELISA antibody titers were confirmed for three lots of a CMV hyperimmune preparation, the functionally more relevant CMV neutralizing antibody titers were significantly higher for 31 lots of standard IVIG preparations. Moreover, considerably lower IgG3 levels were found for the CMV hyperimmune preparation compared with standard IVIG preparations. The higher functional CMV neutralization titers of standard IVIG preparations and the better availability of these preparations, suggest that these products could be a valuable alternative to the CMV hyperimmune preparation.

  10. Enzymes - important players in green chemistry

    Directory of Open Access Journals (Sweden)

    Agata Tarczykowska

    2017-09-01

    Full Text Available Green chemistry has become a worldwide approach that leads to sustainable growth through application and development of its principles. A lot of work has to be put into designing new processes comprising of materials which do not emit pollutants to the atmosphere. Inventing new safer methods and finding less harmful products can be challenging. Enzymes are a great hope of scientists in the field of green chemistry. Enzymes as catalysts require mild conditions therefore it is a great way of saving resources such as energy or water. Processes with the use of enzymes have become more feasible by being more cost effective and eco friendly. Taking into account the benefits of green chemistry, enzyme biocatalysis has quickly replaced traditional chemical processes in several fields, and this substitution is going to reach even more areas because of new emerging technologies in enzyme engineering.

  11. Practical steady-state enzyme kinetics.

    Science.gov (United States)

    Lorsch, Jon R

    2014-01-01

    Enzymes are key components of most biological processes. Characterization of enzymes is therefore frequently required during the study of biological systems. Steady-state kinetics provides a simple and rapid means of assessing the substrate specificity of an enzyme. When combined with site-directed mutagenesis (see Site-Directed Mutagenesis), it can be used to probe the roles of particular amino acids in the enzyme in substrate recognition and catalysis. Effects of interaction partners and posttranslational modifications can also be assessed using steady-state kinetics. This overview explains the general principles of steady-state enzyme kinetics experiments in a practical, rather than theoretical, way. Any biochemistry textbook will have a section on the theory of Michaelis-Menten kinetics, including derivations of the relevant equations. No specific enzymatic assay is described here, although a method for monitoring product formation or substrate consumption over time (an assay) is required to perform the experiments described. © 2014 Elsevier Inc. All rights reserved.

  12. Evaluation of thermostable enzymes for bioethanol processing

    DEFF Research Database (Denmark)

    Skovgaard, Pernille Anastasia

    of fermentable sugars (glucose) as cellulose is tightly linked to hemicellulose and lignin. Lignocellulose is disrupted during pretreatment, but to degrade cellulose to single sugars, lignocellulolytic enzymes such as cellulases and hemicellulases are needed. Lignocellulolytic enzymes are costly...... for the ioethanol production, but the expenses can be reduced by using thermostable enzymes, which are known for their increased stability and inhibitor olerance. However, the advantage of using thermostable enzymes has not been studied thoroughly and more knowledge is needed for development of bioethanol processes....... Enzymes are added to the bioethanol process after pretreatment. For an efficient sugar and ethanol yield, the solids content of biomass is normally increased, which results in highly viscous slurries that are difficult to mix. Therefore, the first enzymatic challenge is to ensure rapid reduction...

  13. Enhanced Oil Recovery with Application of Enzymes

    DEFF Research Database (Denmark)

    Khusainova, Alsu

    Enzymes have recently been reported as effective enhanced oil recovery (EOR) agents. Both laboratory and field tests demonstrated significant increase in the ultimate oil production. Up to16% of additional oil was produced in the laboratory conditions and up to 269 barrels of additional oil per day...... were recovered in the field applications. The following mechanisms were claimed to be responsible for the enhancement of the oil production due to enzymes: wettability improvement of the rock surface; formation of the emulsions; reduction of oil viscosity; and removal of high molecular weight paraffins....... However, the positive effect of enzymes on oil recovery is not that obvious. In most of the studies commercial enzyme products composed of enzymes, surfactants and stabilisers were used. Application of such samples makes it difficult to assign a positive EOR effect to a certain compound, as several...

  14. Fungal enzymes in the attine ant symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    the more basal attine genera use substrates such as flowers, plant debris, small twigs, insect feces and insect carcasses. This diverse array of fungal substrates across the attine lineage implies that the symbiotic fungus needs different enzymes to break down the plant material that the ants provide...... or different efficiencies of enzyme function. Fungal enzymes that degrade plant cell walls may have functionally co-evolved with the ants in this scenario. We explore this hypothesis with direct measurements of enzyme activity in fungus gardens in 12 species across 8 genera spanning the entire phylogeny...... and diversity of life-styles within the attine clade. We find significant differences in enzyme activity between different genera and life-styles of the ants. How these findings relate to attine ant coevolution and crop optimization are discussed....

  15. Production of cellulolytic enzymes from ascomycetes

    DEFF Research Database (Denmark)

    Hansen, Gustav Hammerich; Lübeck, Mette; Frisvad, Jens Christian

    2015-01-01

    Optimizing production of cellulose degrading enzymes is of great interest in order to increase the feasibility of constructing biorefinery facilities for a sustainable supply of energy and chemical products. The ascomycete phylum has a large potential for the production of cellulolytic enzymes....... Although numerous enzymatic profiles have already been unraveled, the research has been covering only a limited number of species and genera, thus leaving many ascomycetes to be analyzed. Such analysis requires choosing appropriate media and cultivation methods that ensure enzyme profiles with high...... specificities and activities. However, the choice of media, cultivation methods and enzyme assays highly affect the enzyme activity profile observed. This review provides an overview of enzymatic profiles for several ascomycetes covering phylogenetically distinct genera and species. The profiles of cellulose...

  16. Covalent Immobilization of Cellulase Using Magnetic Poly(ionic liquid) Support: Improvement of the Enzyme Activity and Stability.

    Science.gov (United States)

    Hosseini, Seyed Hassan; Hosseini, Seyedeh Ameneh; Zohreh, Nasrin; Yaghoubi, Mahshid; Pourjavadi, Ali

    2018-01-31

    A magnetic nanocomposite was prepared by entrapment of Fe 3 O 4 nanoparticles into the cross-linked ionic liquid/epoxy type polymer. The resulting support was used for covalent immobilization of cellulase through the reaction with epoxy groups. The ionic surface of the support improved the adsorption of enzyme, and a large amount of enzyme (106.1 mg/g) was loaded onto the support surface. The effect of the presence of ionic monomer and covalent binding of enzyme was also investigated. The structure of support was characterized by various instruments such as FT-IR, TGA, VSM, XRD, TEM, SEM, and DLS. The activity and stability of immobilized cellulase were investigated in the prepared support. The results showed that the ionic surface and covalent binding of enzyme onto the support improved the activity, thermal stability, and reusability of cellulase compared to free cellulase.

  17. Where do the immunostimulatory effects of oral proteolytic enzymes ('systemic enzyme therapy') come from? Microbial proteolysis as a possible starting point.

    Science.gov (United States)

    Biziulevicius, Gediminas A

    2006-01-01

    Enteric-coated proteolytic enzyme preparations like Wobenzym and Phlogenzym are widely used for the so-called 'systemic enzyme therapy' both in humans and animals. Numerous publications reveal that oral proteolytic enzymes are able to stimulate directly the activity of immune competent cells as well as to increase efficiency of some of their products. But origins of the immunostimulatory effects of oral proteolytic enzymes are still unclear. The hypothesis described here suggests that it may be proteolysis of intestinal microorganisms that makes the immune competent cells to work in the immunostimulatory manner. The hypothesis was largely formed by several scientific observations: First, microbial lysis products (lipopolysaccharides, muropeptides and other peptidoglycan fragments, beta-glucans, etc.) are well known for their immunostimulatory action. Second, a normal human being hosts a mass of intestinal microorganisms equivalent to about 1 kg. The biomass (mainly due to naturally occurring autolysis) continuously supplies the host's organism with immunostimulatory microbial cell components. Third, the immunostimulatory effects resulting from the oral application of exogenously acting antimicrobial (lytic) enzyme preparations, such as lysozyme and lysosubtilin, are likely to be a result of the action of microbial lysis products. Fourth, cell walls of most microorganisms contain a considerable amount of proteins/peptides, a possible target for exogenous proteolytic enzymes. In fact, several authors have already shown that a number of proteases possess an ability to lyse the microbial cells in vitro. Fifth, the pretreatment of microbial cells (at least of some species) in vitro with proteolytic enzymes makes them more sensitive to the lytic action of lysozyme and, otherwise, pretreatment with lysozyme makes them more susceptible to proteolytic degradation. Sixth, exogenous proteases, when in the intestines, may participate in final steps of food-protein digestion

  18. Materials Preparation Center

    Data.gov (United States)

    Federal Laboratory Consortium — MPC is recognized throughout the worldwide research community for its unique capabilities in purification, preparation, and characterization of: rare earth metals,...

  19. Visualization of enzyme activities inside earthworm biopores by in situ soil zymography

    Science.gov (United States)

    Thu Duyen Hoang, Thi; Razavi, Bahar. S.; Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2015-04-01

    Earthworms can strongly activate microorganisms, increase microbial and enzyme activities and consequently the turnover of native soil organic matter. In extremely dynamic microhabitats and hotspots as biopores made by earthworms, the in situ enzyme activities are a footprint of complex biotic interactions. The effect of earthworms on the alteration of enzyme activities inside biopores and the difference between bio-pores and earthworm-free soil was visualized by in situ soil zymography (Spohn and Kuzyakov, 2014). For the first time, we prepared quantitative imaging of enzyme activities in biopores. Furthermore, we developed the zymography technique by direct application of a substrate saturated membrane to the soil to obtain better spatial resolution. Lumbricus terrestris L. was placed into transparent box (15×20×15cm). Simultaneously, maize seed was sown in the soil. Control soil box with maize and without earthworm was prepared in the same way. After two weeks when bio-pore systems were formed by earthworm, we visualized in situ enzyme activities of five hydrolytic enzymes (β-glucosidase, cellobiohydrolase, chitinase, xylanase, leucine aminopeptidase) and phosphatase. Followed by non-destructive zymography, biopore samples and control soil were destructively collected to assay enzyme kinetics by fluorogenically labeled substrates method. Zymography showed higher activity of β-glucosidase, chitinase, xylanase and phosphatase in biopores comparing to bulk soil. These differences were further confirmed by fluorimetric microplate enzyme assay detected significant difference of Vmax in four above mentioned enzymes. Vmax of β-glucosidase, chitinase, xylanase and phosphatase in biopores is 68%, 108%, 50% and 49% higher than that of control soil. However, no difference in cellobiohydrolase and leucine aminopeptidase kinetics between biopores and control soil were detected. This indicated little effect of earthworms on protein and cellulose transformation in soil

  20. Increased saccharification of kallar grass using ultrafiltrated enzyme from sporrotrichum thermophile

    International Nuclear Information System (INIS)

    Latif, F.; Rajoka, M.I.; Malik, K.A.

    1991-01-01

    The local wild type strain of sporotrichum thermophile when grown on untreated lingo cellulose was found to produce a greater level of B-glucosidase component along with other cellulase/xylanase components than most of the reported wild type potent strains. Culture filtrate obtained, when grown on 4% leptochloa fusca (kallar grass) was used as such and after concentration by ultrafiltration technique for saccharification purpose. Concentrated enzymes titre was increased to 1.2 and 4.0 U/ml for Fp-ase and B-glucosidase, respectively. There were losses in the enzyme titre obtained through ultrafiltration possibly due to adsorption on to the ultrafiltration membrane. Enzyme preparations used, saccharifide 5% kallar grass to 70, 55, 75 and 60% (theoretical basis) from cellulases of S. thermophile concentrate, dilute, T. reesei alone and in supplementation with B-glucosidase from A. niger, respectively. Analysis by HPLC revealed slightly higher glucose yield from S. thermophile enzyme preparations, whereas higher level of xylose was attained from T. reesei preparations. Rest of the sugars pooled as Oligo-sugars were found in almost similar concentrations. (author)

  1. Expression of Enzymes that Metabolize Medications

    Science.gov (United States)

    Wotring, V. E.; Peters, C. P.

    2011-01-01

    INTRODUCTION: Increased exposure to radiation is one physiological stressor associated with spaceflight and it is feasible to conduct ground experiments using known radiation exposures. The health of the liver, especially the activity rate of its metabolic enzymes, determines the concentration of circulating drugs as well as the duration of their efficacy. While radiation is known to alter normal physiological function, how radiation affects liver metabolism of administered medications is unclear. Crew health could be affected if the actions of medications used in spaceflight deviated from expectations formed during terrestrial medication use. This study is an effort to identify liver metabolic enzymes whose expression is altered by spaceflight or by radiation exposures that mimic features of the spaceflight environment. METHODS: Using procedures approved by the Animal Care and Use Committee, mice were exposed to either 137Cs (controls, 50 mGy, 6Gy, or 50 mGy + 6Gy separated by 24 hours) or 13 days of spaceflight on STS 135. Animals were anesthetized and sacrificed at several time points (4 hours, 24 hours or 7 days) after their last radiation exposure, or within 6 hours of return to Earth for the STS 135 animals. Livers were removed immediately and flash-frozen in liquid nitrogen. Tissue was homogenized, RNA extracted, purified and quality-tested. Complementary DNA was prepared from high-quality RNA samples, and used in RT-qPCR experiments to determine relative expression of a wide variety of genes involved in general metabolism and drug metabolism. RESULTS: Results of the ground radiation exposure experiments indicated 65 genes of the 190 tested were significantly affected by at least one of the radiation doses. Many of the affected genes are involved in the metabolism of drugs with hydrophobic or steroid-like structures, maintenance of redox homeostasis and repair of DNA damage. Most affected genes returned to near control expression levels by 7 days post

  2. Expanding the Halohydrin Dehalogenase Enzyme Family: Identification of Novel Enzymes by Database Mining.

    Science.gov (United States)

    Schallmey, Marcus; Koopmeiners, Julia; Wells, Elizabeth; Wardenga, Rainer; Schallmey, Anett

    2014-12-01

    Halohydrin dehalogenases are very rare enzymes that are naturally involved in the mineralization of halogenated xenobiotics. Due to their catalytic potential and promiscuity, many biocatalytic reactions have been described that have led to several interesting and industrially important applications. Nevertheless, only a few of these enzymes have been made available through recombinant techniques; hence, it is of general interest to expand the repertoire of these enzymes so as to enable novel biocatalytic applications. After the identification of specific sequence motifs, 37 novel enzyme sequences were readily identified in public sequence databases. All enzymes that could be heterologously expressed also catalyzed typical halohydrin dehalogenase reactions. Phylogenetic inference for enzymes of the halohydrin dehalogenase enzyme family confirmed that all enzymes form a distinct monophyletic clade within the short-chain dehydrogenase/reductase superfamily. In addition, the majority of novel enzymes are substantially different from previously known phylogenetic subtypes. Consequently, four additional phylogenetic subtypes were defined, greatly expanding the halohydrin dehalogenase enzyme family. We show that the enormous wealth of environmental and genome sequences present in public databases can be tapped for in silico identification of very rare but biotechnologically important biocatalysts. Our findings help to readily identify halohydrin dehalogenases in ever-growing sequence databases and, as a consequence, make even more members of this interesting enzyme family available to the scientific and industrial community. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  3. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    Science.gov (United States)

    Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

    2015-01-01

    The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

  4. Metagenomics as a Tool for Enzyme Discovery: Hydrolytic Enzymes from Marine-Related Metagenomes.

    Science.gov (United States)

    Popovic, Ana; Tchigvintsev, Anatoly; Tran, Hai; Chernikova, Tatyana N; Golyshina, Olga V; Yakimov, Michail M; Golyshin, Peter N; Yakunin, Alexander F

    2015-01-01

    This chapter discusses metagenomics and its application for enzyme discovery, with a focus on hydrolytic enzymes from marine metagenomic libraries. With less than one percent of culturable microorganisms in the environment, metagenomics, or the collective study of community genetics, has opened up a rich pool of uncharacterized metabolic pathways, enzymes, and adaptations. This great untapped pool of genes provides the particularly exciting potential to mine for new biochemical activities or novel enzymes with activities tailored to peculiar sets of environmental conditions. Metagenomes also represent a huge reservoir of novel enzymes for applications in biocatalysis, biofuels, and bioremediation. Here we present the results of enzyme discovery for four enzyme activities, of particular industrial or environmental interest, including esterase/lipase, glycosyl hydrolase, protease and dehalogenase.

  5. Expression of lignocellulolytic enzymes in Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Mellitzer Andrea

    2012-05-01

    Full Text Available Abstract Background Sustainable utilization of plant biomass as renewable source for fuels and chemical building blocks requires a complex mixture of diverse enzymes, including hydrolases which comprise the largest class of lignocellulolytic enzymes. These enzymes need to be available in large amounts at a low price to allow sustainable and economic biotechnological processes. Over the past years Pichia pastoris has become an attractive host for the cost-efficient production and engineering of heterologous (eukaryotic proteins due to several advantages. Results In this paper codon optimized genes and synthetic alcohol oxidase 1 promoter variants were used to generate Pichia pastoris strains which individually expressed cellobiohydrolase 1, cellobiohydrolase 2 and beta-mannanase from Trichoderma reesei and xylanase A from Thermomyces lanuginosus. For three of these enzymes we could develop strains capable of secreting gram quantities of enzyme per liter in fed-batch cultivations. Additionally, we compared our achieved yields of secreted enzymes and the corresponding activities to literature data. Conclusion In our experiments we could clearly show the importance of gene optimization and strain characterization for successfully improving secretion levels. We also present a basic guideline how to correctly interpret the interplay of promoter strength and gene dosage for a successful improvement of the secretory production of lignocellulolytic enzymes in Pichia pastoris.

  6. Plant cell-wall hydrolyzing enzymes from indigenously isolated fungi grown on conventional and novel natural substrates

    International Nuclear Information System (INIS)

    Kumari, D.; Sohail, M.; Jahangeer, S.; Abideen, Z.; Khan, M.A.

    2017-01-01

    Fungi elaborate a variety of plant-hydrolyzing enzymes including cellulases, xylanases, pectinases and amylases. Although these enzymes have potential biotechnological applications, their production at industrial level is limited because of higher costs of the purified substrates. Hence, the present study was aimed to explore the novel, natural and cheaper substrates for enzyme production. Indigenously isolated fungal strains of Aspergillus sp. were grown on banana-peels, grapefruit-peels, pomegranate-peels, sugarcane bagasse, Eucalyptus camaldulensis-leaves and shoots of two halophytic plants including Halopyrum mucronatum and Desmostachya bipinnata under solid-state fermentation (SSF) and submerged fermentation (Smf) conditions. The crude enzyme preparation was screened for cellulase (endoglucanase, beta-glucosidase and filter-paperase), hemicellulase (xylanase), pectinase and amylase production. The results revealed that among all investigated enzymes, the xylanase titers were highest using D. bipinnata- shoots and H. mucronatum- shoots as substrates under solid state fermentation conditions, suggesting their exploitation at commercial scale. (author)

  7. Documents preparation and review

    International Nuclear Information System (INIS)

    1999-01-01

    Ignalina Safety Analysis Group takes active role in assisting regulatory body VATESI to prepare various regulatory documents and reviewing safety reports and other documentation presented by Ignalina NPP in the process of licensing of unit 1. The list of main documents prepared and reviewed is presented

  8. Immobilized enzyme studies in a microscale bioreactor.

    Science.gov (United States)

    Jones, Francis; Forrest, Scott; Palmer, Jim; Lu, Zonghuan; Elmore, John; Elmore, Bill B

    2004-01-01

    Novel microreactors with immobilized enzymes were fabricated using both silicon and polymer-based microfabrication techniques. The effectiveness of these reactors was examined along with their behavior over time. Urease enzyme was successfully incorporated into microchannels of a polymeric matrix of polydimethylsiloxane and through layer-bylayer self-assembly techniques onto silicon. The fabricated microchannels had cross-sectional dimensions ranging from tens to hundreds of micrometers in width and height. The experimental results for continuous-flow microreactors are reported for the conversion of urea to ammonia by urease enzyme. Urea conversions of >90% were observed.

  9. Enzyme-based antifouling coatings: a review

    DEFF Research Database (Denmark)

    Olsen, Stefan Møller; Pedersen, Leif Toudal; Laursen, M.H.

    2007-01-01

    A systematic overview is presented of the literature that reports the antifouling (AF) protection of underwater structures via the action of enzymes. The overall aim of this review is to assess the state of the art of enzymatic AF technology, and to highlight the obstacles that have to be overcome...... for successful development of enzymatic AF coatings. The approaches described in the literature are divided into direct and indirect enzymatic AF, depending on the intended action of the enzymes. Direct antifouling is used when the enzymes themselves are active antifoulants. Indirect antifouling refers...

  10. Enzymic hydrolysis of cellulosic wastes to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Spano, L A; Medeiros, J; Mandels, M

    1976-01-01

    An enzymic process for the conversion of cellulose to glucose is based on the use of a specific enzyme derived from mutant strains of the fungus trichoderma viride which is capable of reacting with the crystalline fraction of the cellulose molecule. The production and mode of action of the cellulase complex produced during the growth of trichoderma viride is discussed as well as the application of such enzymes for the conversion of cellulosic wastes to crude glucose syrup for use in production of chemical feedstocks, single-cell proteins, fuels, solvents, etc.

  11. Dibromine radical anion reactions with heme enzymes

    International Nuclear Information System (INIS)

    Gebicka, L.; Gebicki, J.L.

    1996-01-01

    Reactions of Br 2 radical anion with heme enzymes, catalase horseradish peroxidase, have been studied by pulse radiolysis. It has been found that Br 2 - does not react with the heme centre of investigated enzymes. Dibromine radical anion reacts with tryptophan residues of catalase without any influence on the activity of catalase. It is suggested that in pulse radiolysis studies, where horseradish peroxidase is at about tenfold excess toward Br 2 - , the enzyme is modified rather by Br 2 , than by Br 2 - . (author). 26 refs., 3 figs

  12. Dimeric assembly of enterocyte brush border enzymes

    DEFF Research Database (Denmark)

    Danielsen, E M

    1994-01-01

    The noncovalent, dimeric assembly of small intestinal brush border enzymes was studied by sedimentation analysis in density gradients of extracts of pulse-labeled pig jejunal mucosal explants. Like aminopeptidase N (EC 3.4.11.2), sucrase-isomaltase (EC 3.2.1.48-10), aminopeptidase A (EC 3...... appearance of the liposome-reconstituted enzyme [Norén et al. (1986) J. Biol. Chem. 261, 12306-12309], showing only the inner, membrane-anchored domains of the monomers to be in close contact with one another while the outer domains are far apart. In contrast to the other brush border enzymes studied...

  13. Enzyme Treatment-Free and Ligation-Independent Cloning Using Caged Primers in Polymerase Chain Reactions

    Directory of Open Access Journals (Sweden)

    Akinori Kuzuya

    2011-12-01

    Full Text Available A new simple scheme for constructing recombinant vectors that does not require any restriction enzyme, ligase, or any other special enzyme treatment has been developed. By using caged primers in PCR, unnatural sticky-ends of any sequence, which are sufficiently long for ligation-independent cloning (LIC, are directly prepared on the product after a brief UVA irradiation. Target genes and vectors amplified by this light-assisted cohesive-ending (LACE PCR join together in the desired arrangement in a simple mixture of them, tightly enough to be repaired and ligated in competent cells.

  14. Ultrarapid sonochemical synthesis of enzyme-incorporated copper nanoflowers and their application to mediatorless glucose biofuel cell

    Science.gov (United States)

    Chung, Minsoo; Nguyen, Tuan Loi; Tran, Thao Quynh Ngan; Yoon, Hyon Hee; Kim, Il Tae; Kim, Moon Il

    2018-01-01

    We have developed a mediatorless glucose biofuel cell based on hybrid nanoflowers incorporating enzymes including glucose oxidase (GOx), laccase, or catalase with copper phosphate, which were further mixed and compressed with conductive multi-walled carbon nanotube (CNT). The nanoflowers were simply synthesized within 5 min at room temperature using sonication method but yielded greatly improved stability as well as highly retained activity by the proper incorporation of enzyme molecules inside the flower-like structure. With glucose as biofuel, GOx and laccase nanoflowers were applied to form enzyme anode and cathode, respectively, and catalase nanoflowers were additionally employed to catalyze the decomposition of hydrogen peroxide, which may be deleterious for GOx, into oxygen and water. Using the enzyme nanoflowers-based biofuel cell system without any involved mediator, a high power density up to 200 μW cm-2 were obtained, which was approximately 80% to that from the biofuel cell system prepared with the corresponding free enzymes. Importantly, the enzyme nanoflowers-based biofuel cell maintained their initial power density over 90% during storage for two months at 4 °C, while most of the glucose biofuel cells in the literature present meaningful stability only in the range of one or two weeks. Based on this result, we expect that this simple but efficient strategy to prepare highly stable glucose biofuel cell using the rapidly-synthesized enzyme-inorganic hybrid nanoflowers can be readily extended to diverse applications in medical and environmental chemistry.

  15. Dietary modulation of thymic enzymes.

    Science.gov (United States)

    Susana, Feliu María; Paula, Perris; Slobodianik, Nora

    2014-01-01

    Malnutrition is a complex syndrome caused by an inadequate intake of energy, protein, minerals and vitamins which affects the immune system. Nutritional imbalances, present in children with energy-protein malnutrition and infections, make defining the specific effects of each of them on the thymus difficult. For this reason, it is necessary to design an experimental model in animals that could define a single variable. As the thymus atrophy described in humans is similar to that observed in murines, a rat experimental model makes the extrapolation to man possible. Some authors suggest that the activity of Adenosine Deaminase (ADA) and Purine Nucleoside Phosphorylase (PNP)--involved in purine metabolism--have an influence on T lymphocyte development and the immune system, due to intracellular accumulation of toxic levels of deoxynucleotides. Studies in our group, performed in an experimental model on Wistar growing rats, have demonstrated that protein deficiency or imbalance in the profile of essential amino acids in the diet, produce loss of thymus weight, reduction in the number of thymocytes, a diminished proportion of T cells presenting the W3/13 antigenic determinant and DNA content with concomitant increase in cell size, and the proportion of immature T cells and activity of ADA and PNP, without modifying the activity of 5´Nucleotidase in the thymus. It is important to point out that there were neither differences in energy intake between experimental groups and their controls, nor clinical symptoms of deficiency of other nutrients. The increase in these thymic enzyme activities was an alternative mechanism to avoid the accumulation of high levels of deoxynucleotides, which would be toxic for T lymphocytes. On the other hand, the administration of a recovery diet, with a high amount of high quality protein, was able to reverse the mentioned effects. The quick reply of Adenosine Deaminase to nutritional disorders and the following nutritional recovery, points

  16. Study on the inactivation of intracellular enzyme molecules by X-ray irradiation

    International Nuclear Information System (INIS)

    Lee, S.B.

    1977-01-01

    Inactivation of the glutamic acid dehydrogenase and glucose-6-phosphate dehydrogenase enzyme molecules in the Ehrlich ascites tumor cells of the mouse were studied. The above mentioned intracellular enzyme molecules were irradiated by the X-ray radiation under the condition of 65 kV, 1 Amp under the atmosphere of nitrogen gases and by 4 0 C. Thereby, irradiation doses were 580 KR/min(error: +-3%). After irradiation, the cell homogentes were prepared through liquid air techniques. There after, the activities of the enzymes were measured with photometric method given by O. Warburg and W. Christian. The dose effect curves of the activities of the two enzymes by the X-ray irradiation showed both exponential and the inactivation doses were 6.5x10 6 and 5.0x10 6 R respectively. These results showed one side that the inactivation process of the intracellular enzyme molecules was one hit reaction after target theory, and the other side that this inactivation process could not be the primary causes of the death through X-ray irradiation of the vertebrate animals, because of the high resistance of the intracellular protein molecules against X-ray irradiation. The one hit reaction by the inactivation process of the irradiated intracellular enzyme molecules was discussed. (author)

  17. Influence of exogenous fibrolytic enzymes on in vitro and in sacco degradation of forages for ruminants

    Directory of Open Access Journals (Sweden)

    Lorenzo Carreón

    2010-02-01

    Full Text Available An in vitro assay was carried out to evaluate the effects of exogenous fibrolytic enzymes (1, 2, 3 and 4 g/kg DM powder preparation containing xylanase and cellulase from Aspergillus niger and Trichoderma viride on DM, NDF and ADF degradation of alfalfa hay, corn silage, corn stover, elephant grass, Guinea grass and oat straw. Kinetics data of in vitro degradations were analyzed. The potentially degradable fraction and degradation rate of NDF and ADF of alfalfa increased quadratically (P<0.05 as the inclusion level of enzyme increased up to 3 g. The others forages were not affected by the enzyme. An in sacco trail was performed using four Holstein steers fitted with ruminal cannulas to evaluate the effects of the exogenous fibrolytic enzymes (3 g/kg DM on DM, NDF and ADF degradation of alfalfa hay and corn stover. Kinetics data were also analyzed. The potentially degradable fraction degradation of NDF (62.0 vs 65.7% and ADF (52.8 vs 56.9%, of alfalfa hay were increased (P<0.05 by the exogenous fibrolytic enzymes, but no differences were found for corn stover. These results suggest that the enzymes increased in vitro and in sacco fibre degradation only for alfalfa hay.

  18. Highly efficient enzyme encapsulation in a protein nanocage: towards enzyme catalysis in a cellular nanocompartment mimic

    Science.gov (United States)

    Schoonen, Lise; Nolte, Roeland J. M.; van Hest, Jan C. M.

    2016-07-01

    The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions.The study of enzyme behavior in small nanocompartments is crucial for the understanding of biocatalytic processes in the cellular environment. We have developed an enzymatic conjugation strategy to attach a model enzyme to the interior of a cowpea chlorotic mottle virus capsid. It is shown that with this methodology high encapsulation efficiencies can be achieved. Additionally, we demonstrate that the encapsulation does not affect the enzyme performance in terms of a decreased activity or a hampered substrate diffusion. Finally, it is shown that the encapsulated enzymes are protected against proteases. We believe that our strategy can be used to study enzyme kinetics in an environment that approaches physiological conditions. Electronic supplementary information (ESI) available: Experimental procedures for the cloning, expression, and purification of all proteins, as well as supplementary figures and calculations. See DOI: 10.1039/c6nr04181g

  19. Impact of enzyme loading on the efficacy and recovery of cellulolytic enzymes immobilized on enzymogel nanoparticles.

    Science.gov (United States)

    Samaratunga, Ashani; Kudina, Olena; Nahar, Nurun; Zakharchenko, Andrey; Minko, Sergiy; Voronov, Andriy; Pryor, Scott W

    2015-03-01

    Cellulase and β-glucosidase were adsorbed on a polyacrylic acid polymer brush grafted on silica nanoparticles to produce enzymogels as a form of enzyme immobilization. Enzyme loading on the enzymogels was increased to a saturation level of approximately 110 μg (protein) mg(-1) (particle) for each enzyme. Enzymogels with varied enzyme loadings were then used to determine the impact on hydrolysis rate and enzyme recovery. Soluble sugar concentrations during the hydrolysis of filter paper and Solka-Floc with the enzymogels were 45 and 53%, respectively, of concentrations when using free cellulase. β-Glucosidase enzymogels showed lower performance; hydrolyzate glucose concentrations were just 38% of those using free enzymes. Increasing enzyme loading on the enzymogels did not reduce net efficacy for cellulase and improved efficacy for β-glucosidase. The use of free cellulases and cellulase enzymogels resulted in hydrolyzates with different proportions of cellobiose and glucose, suggesting differential attachment or efficacy of endoglucanases, exoglucanases, and β-glucosidases present in cellulase mixtures. When loading β-glucosidase individually, higher enzyme loadings on the enzymogels produced higher hydrolyzate glucose concentrations. Approximately 96% of cellulase and 66 % of β-glucosidase were recovered on the enzymogels, while enzyme loading level did not impact recovery for either enzyme.

  20. PREPARATIVE SKIN PREPARATION AND SURGICAL WOUND INFECTION

    Directory of Open Access Journals (Sweden)

    Anjanappa

    2015-01-01

    Full Text Available BACKGROUND AND OBJECTIVE: It is an established fact now that the normal skin of healthy human beings harbours a rich bacterial fl ora. Normally considered non - pathogenic , these organisms way be a potential source of infection of the surgical wound. Approximately 20% of the resident flora is beyond the reach of surgical scrubs and antiseptics. The goal of surgical preparation of the skin with antiseptics is to remove transient and pathogenic microorganisms on the skin surface and to reduce the resident flora to a low level. Povidone iodine (I odophors and chlorhexidine are most often used antiseptics for pre - operative skin preparation. OBJECTIVES : To evaluate the efficacy of povidone iodine alone and in combination with antiseptic agent containing alcoholic chlorhexidine in preoperative skin p reparation by taking swab culture. (2 To compare the rate of postoperative wound infection in both the groups. METHODS: One hundred patients (fifty in each group undergoing clean elective surgery with no focus of infection on the body were included in th e study. The pre - operative skin preparation in each group is done with the respective antiseptic regimen. In both the groups after application of antiseptics , sterile saline swab culture was taken immediately from site of incision. In cases which showed gr owth of organisms , the bacteria isolated were identified by their morphological and cultural characteristics. Grams staining , coagulase test and antibiotic sensitivity test were done wherever necessary and difference in colonization rates was determined as a measure of efficacy of antiseptic regimen. RESULTS: The results of the study showed that when compared to povidone iodine alone , using a combination of povidone iodine and alcoholic solution of chlorhexidine , the colonization rates of the site of incisi on were reduced significantly. As for the rate of post - operative wound infection , it is also proven that wound infections are also

  1. Role of antioxidant scavenging enzymes and extracellular ...

    African Journals Online (AJOL)

    ChithrashreeGS

    2012-08-23

    Aug 23, 2012 ... peroxidase are two important antioxidant scavenging enzymes involved in ... Catalase was assayed using the method of Beers and Sizer. (1951) with .... yeast dextrose calcium carbonate agar (YDC) medium. Catalase and ...

  2. Involvement of methyltransferases enzymes during the energy

    African Journals Online (AJOL)

    Mgina

    INVOLVEMENT OF METHYLTRANSFERASES ENZYMES DURING THE. ENERGY METABOLISM OF ..... cell extract still exhibited relatively high methanogenesis with methanol (Fig ... product CH3-CoM into methane (see Fig. 1). The HS-CoM ...

  3. Optimizing culture medium for debittering constitutive enzyme ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-08-02

    Aug 2, 2010 ... enzyme naringinase production by Aspergillus oryzae. JMU316. Dong-xiao .... even though industrial applications of naringinase are becoming more and ... guidance for industry. MATERIALS AND ..... For economic reasons,.

  4. distribution, abundance and properties of restriction enzymes

    African Journals Online (AJOL)

    DNA of granule-bound starch synthase (GBSS) I and II with a view to ... properties for manipulation of the genes for production of modified starch. .... procurement, storage and handling of the ..... been made on restriction enzymes of potato,.

  5. Novel enzymes for the degradation of cellulose

    Directory of Open Access Journals (Sweden)

    Horn Svein

    2012-07-01

    Full Text Available Abstract The bulk terrestrial biomass resource in a future bio-economy will be lignocellulosic biomass, which is recalcitrant and challenging to process. Enzymatic conversion of polysaccharides in the lignocellulosic biomass will be a key technology in future biorefineries and this technology is currently the subject of intensive research. We describe recent developments in enzyme technology for conversion of cellulose, the most abundant, homogeneous and recalcitrant polysaccharide in lignocellulosic biomass. In particular, we focus on a recently discovered new type of enzymes currently classified as CBM33 and GH61 that catalyze oxidative cleavage of polysaccharides. These enzymes promote the efficiency of classical hydrolytic enzymes (cellulases by acting on the surfaces of the insoluble substrate, where they introduce chain breaks in the polysaccharide chains, without the need of first “extracting” these chains from their crystalline matrix.

  6. Archaeal Enzymes and Applications in Industrial Biocatalysts.

    Science.gov (United States)

    Littlechild, Jennifer A

    2015-01-01

    Archaeal enzymes are playing an important role in industrial biotechnology. Many representatives of organisms living in "extreme" conditions, the so-called Extremophiles, belong to the archaeal kingdom of life. This paper will review studies carried by the Exeter group and others regarding archaeal enzymes that have important applications in commercial biocatalysis. Some of these biocatalysts are already being used in large scale industrial processes for the production of optically pure drug intermediates and amino acids and their analogues. Other enzymes have been characterised at laboratory scale regarding their substrate specificity and properties for potential industrial application. The increasing availability of DNA sequences from new archaeal species and metagenomes will provide a continuing resource to identify new enzymes of commercial interest using both bioinformatics and screening approaches.

  7. Radioimmunoassay of polypeptide hormones and enzymes

    International Nuclear Information System (INIS)

    Felber, J.P.

    1974-01-01

    General principles of radioimmunoassay are reviewed. Detailed procedures are reviewed for the following hormones: insulin, pituitary hormones, gonadotropins, parathyroid hormone, ACTH, glucagon, gastrin, and peptide hormones. Radioimmunoassay of enzymes is also discussed. (U.S.)

  8. Extracellular enzyme kinetics scale with resource availability

    Science.gov (United States)

    Sinsabaugh, Robert L.; Belnap, Jayne; Findlay, Stuart G.; Follstad Shah, Jennifer J.; Hill, Brian H.; Kuehn, Kevin A.; Kuske, Cheryl; Litvak, Marcy E.; Martinez, Noelle G.; Moorhead, Daryl L.; Warnock, Daniel D.

    2014-01-01

    Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent Vmax and apparent Km followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the Km of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales.

  9. Purification and characterization of protease enzyme from ...

    African Journals Online (AJOL)

    The enzyme was active in pH range 5 to11 and temperature of 30 to 80°C. The optimum pH and the temperature for protease activity were recorded to be pH 8 and 50°C, respectively. The enzyme was stable up to 40°C and pH 9. The protease activity was inhibited by Zn2+, Ni2+ and Sn2+ and increased by Ca2+, Mg2+ ...

  10. Enzyme-driven mechanisms in biocorrosion

    OpenAIRE

    Basséguy, Régine

    2007-01-01

    Objectives (abstract of presentation): Recent works carried out in our team concerning enzymes and biocorrosion are presented at the meeting. For aerobic conditions, the direct catalysis of the reduction of oxygen on steel by enzymes or porphyrin was proved and a local electrochemical analysis technique (SVET) was developed to visualize the localization of the catalysis. On anaerobic conditions, the influence of phosphate species and other weak acids on the water reduction on steel was shown....

  11. A stochastic model of enzyme kinetics

    Science.gov (United States)

    Stefanini, Marianne; Newman, Timothy; McKane, Alan

    2003-10-01

    Enzyme kinetics is generally modeled by deterministic rate equations, and in the simplest case leads to the well-known Michaelis-Menten equation. It is plausible that stochastic effects will play an important role at low enzyme concentrations. We have addressed this by constructing a simple stochastic model which can be exactly solved in the steady-state. Throughout a wide range of parameter values Michaelis-Menten dynamics is replaced by a new and simple theoretical result.

  12. Enzyme Technology for Shipboard Waste Management

    Science.gov (United States)

    1976-12-01

    sucrose to the sweeter invert sugar by the enzyme invertase is a well established process, as is the conversion of starch to glucose by the enzyme...aspects of our health and daily lives. Recent advances in fundamental and applied enzymology indicate that we have already started in that direction. At a...Chemtech, p. 677 (Nov 1973) 11 - Bungay, H. P., "Applied Enzymology ," Worthington, Biochemical Corp., Notes for an AIChE Lecture, Washington, D. C. (Dec

  13. Properties of native and immobilised preparations of. beta. -D-glucosidase from Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Wohlpart, D.L.

    1982-01-01

    The enzyme ..beta..-D-glucosidase from Aspergillus niger has been immobilised through its carbohydrate moiety on concanavalin A-Sepharose and on cyanogen bromide-activated Sepharose after aminoalkylation of the carbohydrate side chains of the enzyme. For comparison, the enzyme was also immobilised on microcrystalline cellulose through its protein moiety. High retention of activity and a decrease in K/sub m/ and V/sub max/ were observed when ..beta..-D-glucosidase was immobilised by these methods. An increase in the thermal stability of the immobilised ..beta..-D-glucosidase preparations over the soluble enzyme was achieved if it was treated with glutaraldehyde before its adsorption on concanavalin A-Sepharose or if the enzyme immobilised on cyanogen bromide-activated Sepharose was subsequently treated with glutaralydehyde. Treatment of ..beta..-D-glucosidase immobilised on microcrystalline cellulose with glutaraldehyde hardy increased its thermal stability over the soluble enzyme.

  14. Properties of native and immobilised preparations of beta-d-glucosidase from Aspergillus niger

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Wohlpart, D.L.

    1982-04-01

    The enzyme beta-glucosidase from Aspergillus niger has been immobilised through its carbohydrate moiety on concanavalin A-Sepharose and on cyanogen bromide-activated Sepharose after aminoalkylation of the carbohydrate side chains of the enzyme. For comparison, the enzyme was also immobilised on microcrystalline cellulose through its protein moiety. High retention of activity and a decrease in Km and Vmax were observed when beta-D-glucosidase was immobilised by these methods. An increase in the thermal stability of the immobilized beta-D-glucosidase preparations over the soluble enzyme was achieved if it was treated with glutaraldehyde before its adsorption on concanavalin A-Sepharose or if the enzyme immobilised on cyanogen bromide-activated Sepharose was subsequently treated with glutaraldehyde. Treatment of beta-D-glucosidase immobilised on microcrystalline cellulose with glutaraldehyde hardly increased its thermal stability over the soluble enzyme. (Refs. 24).

  15. Visualization of enzyme activities inside earthworm pores

    Science.gov (United States)

    Hoang, Duyen; Razavi, Bahar S.

    2015-04-01

    In extremely dynamic microhabitats as bio-pores made by earthworm, the in situ enzyme activities are assumed as a footprint of complex biotic interactions. Our study focused on the effect of earthworm on the enzyme activities inside bio-pores and visualizing the differences between bio-pores and earthworm-free soil by zymography technique (Spohn and Kuzyakov, 2013). For the first time, we aimed at quantitative imaging of enzyme activities in bio-pores. Lumbricus terrestris L. was placed into transparent box (15×20×15cm). After two weeks when bio-pore systems were formed by earthworms, we visualized in situ enzyme activities of five hydrolytic enzymes (β-glucosidase, cellobiohydrolase, chitinase, xylanase, leucine-aminopeptidase, and phosphatase. Zymography showed higher activity of β-glucosidase, chitinase, xylanase and phosphatase in biopores comparing to bulk soil. However, the differences in activity of cellobiohydrolase and leucine aminopeptidase between bio-pore and bulk soil were less pronounced. This demonstrated an applicability of zymography approach to monitor and to distinguish the in situ activity of hydrolytic enzymes in soil biopores.

  16. The ultrasound technology for modifying enzyme activity

    Directory of Open Access Journals (Sweden)

    Meliza Lindsay Rojas

    2016-01-01

    Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly a ims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes ef ficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/in activation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultr asonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

  17. The ultrasound technology for modifying enzyme activity

    Directory of Open Access Journals (Sweden)

    Meliza Lindsay

    2016-06-01

    Full Text Available Enzymes are protein complexes compounds widely studied and used due to their ability to catalyze reactions. The food processing mainly aims the inactivation of enzymes due to various undesirable effects. However, there are many processes that can be optimized by its catalytic activity. In this context, different technologies have been applied both to inactivate or to improve the enzymes efficiency. The Ultrasound technology emerges as an alternative mainly applied to achieve the enzyme inactivation. On the contrary, very few investigations show the ability of this technology under certain conditions to achieve the opposite effect (i.e. increase the catalytic activity of enzymes. The objective of this study was to correlate the ultrasonic energy delivered to the sample (J/mL with the residual enzymatic activity and explain the possible mechanisms which results in the enzymatic activation/inactivation complex behavior. The activity of POD in coconut water was evaluated as a model. The enzymatic activity initially increased, followed by reduction with a trend to enzyme inactivation. This complex behavior is directly related to the applied ultrasonic energy and their direct mechanical effects on the product, as well as the effect in the enzymatic infinite intermediate states and its structural conformation changes. The obtained results are useful for both academic and industrial perspectives.

  18. Directed evolution of enzymes using microfluidic chips

    Science.gov (United States)

    Pilát, Zdeněk.; Ježek, Jan; Šmatlo, Filip; Kaůka, Jan; Zemánek, Pavel

    2016-12-01

    Enzymes are highly versatile and ubiquitous biological catalysts. They can greatly accelerate large variety of reactions, while ensuring appropriate catalytic activity and high selectivity. These properties make enzymes attractive biocatalysts for a wide range of industrial and biomedical applications. Over the last two decades, directed evolution of enzymes has transformed the field of protein engineering. We have devised microfluidic systems for directed evolution of haloalkane dehalogenases in emulsion droplets. In such a device, individual bacterial cells producing mutated variants of the same enzyme are encapsulated in microdroplets and supplied with a substrate. The conversion of a substrate by the enzyme produced by a single bacterium changes the pH in the droplet which is signalized by pH dependent fluorescence probe. The droplets with the highest enzymatic activity can be separated directly on the chip by dielectrophoresis and the resultant cell lineage can be used for enzyme production or for further rounds of directed evolution. This platform is applicable for fast screening of large libraries in directed evolution experiments requiring mutagenesis at multiple sites of a protein structure.

  19. Lysosomal enzyme activation in irradiated mammary tumors

    International Nuclear Information System (INIS)

    Clarke, C.; Wills, E.D.

    1976-01-01

    Lysosomal enzyme activity of C3H mouse mammary tumors was measured quantitatively by a histochemical method. Following whole-body doses of 3600 rad or less no changes were observed in the lysosomal enzyme activity for 12 hr after the irradiation, but very large increases in acid phosphatase and β-naphthylamidase activity were, however, observed 24 hr after irradiation. Significant increases in enzyme activity were detected 72 hr after a dose of 300 rad and the increases of enzyme activity were dose dependent over the range 300 to 900 rad. Testosterone (80 mg/kg) injected into mice 2 hr before irradiation (850 rad) caused a significant increase of lysosomal enzyme activity over and above that of the same dose of irradiation alone. If the tumor-bearing mice were given 95 percent oxygen/5 percent carbon dioxide to breathe for 8 min before irradiation the effect of 850 rad on lysosomal acid phosphatase was increased to 160 percent/that of the irradiation given alone. Activitation of lysosomal enzymes in mammary tumors is an important primary or secondary consequence of radiation

  20. Enzymes for Enhanced Oil Recovery (EOR)

    Energy Technology Data Exchange (ETDEWEB)

    Nasiri, Hamidreza

    2011-04-15

    Primary oil recovery by reservoir pressure depletion and secondary oil recovery by waterflooding usually result in poor displacement efficiency. As a consequence there is always some trapped oil remaining in oil reservoirs. Oil entrapment is a result of complex interactions between viscous, gravity and capillary forces. Improving recovery from hydrocarbon fields typically involves altering the relative importance of the viscous and capillary forces. The potential of many EOR methods depends on their influence on fluid/rock interactions related to wettability and fluid/fluid interactions reflected in IFT. If the method has the potential to change the interactions favorably, it may be considered for further investigation, i.e. core flooding experiment, pilot and reservoir implementation. Enzyme-proteins can be introduced as an enhanced oil recovery method to improve waterflood performance by affecting interactions at the oil-water-rock interfaces. An important part of this thesis was to investigate how selected enzymes may influence wettability and capillary forces in a crude oil-brine-rock system, and thus possibly contribute to enhanced oil recovery. To investigate further by which mechanisms selected enzyme-proteins may contribute to enhance oil recovery, groups of enzymes with different properties and catalytic functions, known to be interfacially active, were chosen to cover a wide range of possible effects. These groups include (1) Greenzyme (GZ) which is a commercial EOR enzyme and consists of enzymes and stabilizers (surfactants), (2) The Zonase group consists of two types of pure enzyme, Zonase1 and Zonase2 which are protease enzymes and whose catalytic functions are to hydrolyze (breakdown) peptide bonds, (3) The Novozyme (NZ) group consists of three types of pure enzyme, NZ2, NZ3 and NZ6 which are esterase enzymes and whose catalytic functions are to hydrolyze ester bonds, and (4) Alpha-Lactalbumin ( -La) which is an important whey protein. The effect of