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Search results for: lactose
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Alternative Lactose Catabolic Pathway in Lactococcus lactis IL1403
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Lactose and β-Glucosides Metabolism and Its Regulation in Lactococcus lactis: A Review
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Beta-Galactosidases of Pseudoalteromonas sp. – Characteristics and application for lactose hydrolysis and galactopyranosides synthesis
PublicationBeta-galactosidase [EC 3.2.1.23] is an enzyme that catalyzes the hydrolysis of O-glycosidic linkages in galactosides. It has biotechnological applications in the dairy industry for the production of milk with a low content of lactose and galactooligosacharides for use in healthy food. The transgalactosylation activity of beta-galactosidase can be used in the synthesis of alkyl galactopyranosides. Due to the fact that conditions of...
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ClaR—a novel key regulator of cellobiose and lactose metabolism in Lactococcus lactis IL1403
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Lactose Content and Selected Quality Parameters of Sheep Milk Fermented Beverages during Storage
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Lactose-rich milk replacer modifies the proteome of bloodplasma in 2-week-old calves
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Thermostable beta-glucosidase with a broad substrate specifity suitable for processing of lactose-containing products.
PublicationHipertermofilny archeon Sulfolobus shibatae wytwarza termostabilną beta glukozydazę przydatną do hydrolizy laktozy w mleku i serwatce przejawiającą największą aktywność w 85 stC przy pH 5,5. Aktywność ekstraktu bezkomórkowego Sulfolobus shibatae wynosi 0.29 U/mg białka i może być 17-krotnie zwiększona poprzez frakcjonowanie siarczanem amonu, chromatografię jonowymienną i filtrację żelową. Badany enzym ma dużą termostabilność i...
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Excessive amount of lactose in the diet of two-week-old calves induces urinary protein changes
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Immobilized preparation of cold-adapted and halotolerant Antarctic β-galactosidase as a highly stable catalyst in lactose hydrolysis
PublicationZimnolubna rekombinowana beta-galaktozydaza antarktycznej morskiej bakterii Pseudoalteromonas sp. 22b została immobilizowana na chitozanie za pomocą aldehydu glutarowego. Preparat immobilizowanego enzymu w przeciwieństwie do preparatu enzymu w buforze reakcyjnym nie był inhibowany przez glukozę. Immobilizacja enzymu wpłynęła na podwyższenie o 10°C optymalnej temperatury aktywności względem jego nieimmobilizowanego odpowiednika...
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Genetic characterization of the CcpA-dependent, cellobiose-specific PTS system comprising CelB, PtcB and PtcA that transports lactose in Lactococcus lactis IL1403
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Analysis of apolipoprotein A-IV expression and the levels of blood plasmamain lipid fractions of calves during the first week of life before and after theadministration of milk replacer supplemented with lactose
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Beta-galactosidases from a psychrotolerant Arthrobacter isolates and their potential use
PublicationEnzymes from extremophiles, especially psychrophiles and psychrotolerant microorganisms are currently intensively studied because of their unusual structural and functional properties. One of these enzymes is a cold-adapted - galactosidase (EC 3.2.1.23) which catalyzes the hydrolysis of - 1,4-glycosidic bonds in -galactosides. The most common - galactoside is lactose, a disaccharide which makes up 2-7% of milk. The majority of...
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A novel cold-active beta-D-galactosidase from the Paracoccus sp. 32d - gene cloning, purification and characterization
PublicationBeta-D-galactosidase (EC 3.2.1.23) catalyze the hydrolysis of terminal non-reducing beta-D-galactose residues in beta-D-galactosides. Cold-active beta-D-galactosidases have recently become a focus of attention of researchers and dairy product manufactures owing to theirs ability to: (I) eliminate of lactose from refrigerated milk for people afflicted with lactose intolerance, (II) convert lactose to glucose and galactose which...
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A novel cold-active β-D-galactosidase with transglycosylation activity from the Antarctic Arthrobacter sp. 32cB - gene cloning, purification and characterization
PublicationA gene encoding a novel β-D-galactosidase from the psychrotolerant Antarctic bacterium Arthrobacter sp. 32cB was isolated, cloned and expressed in Escherichia coli. The active form of recombinant β-D-galactosidase consists of two subunits with a combined molecular weight of approximately 257 kDa. The enzyme's maximum activity towards o-nitrophenyl-β-D-galactopyranoside was determined as occurring at 28 °C and pH 8.0. However, it...
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A new cold-adapted beta-D-galactosidase from the Antarctic Arthrobacter sp. 32c - gene cloning, overexpression, purification and properties
PublicationThe development of a new cold-active β-D-galactosidases and microorganisms that efficiently ferment lactose is of high biotechnological interest, particularly for lactose removal in milk and dairy products at low temperatures and for cheese whey bioremediation processes with simultaneous bio-ethanol production. In this article, we present a new β-D-galactosidase as a candidate to be applied in the above mentioned biotechnological...
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A method for the production of D-tagatose using a recombinant Pichia pastoris strain secreting beta-D-galactosidase from Arthrobacter chlorophenolicus and a recombinant L-arabinose isomerase from Arthrobacter sp. 22c
PublicationD-Tagatose is a natural monosaccharide which can be used as a low-calorie sugar substitute in food, beverages and pharmaceutical products. It is also currently being tested as an anti-diabetic and obesity control drug. D-Tagatose is a rare sugar, but it can be manufactured by the chemical or enzymatic isomerization of D-galactose obtained by a beta-D-galactosidase-catalyzed hydrolysis of milk sugar lactose and the separation of...
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B-GALACTOSIDASE ARTHROBACTER SP. 32cB - OBTAINING THE GENE SEQUENCE, CONSTRUCTION OF THE EXPRESSION SYSTEM, BIOSYNTHESIS AND BIOCHEMICAL CHARACTERIZATION OF THE ENZYME
PublicationINTRODUCTION: β-Galactosidase is an enzyme which catalyzes the hydrolysis of O glycosidic bond in β-galactosides. Another activity of β galactosidase is a transglycosylation activity. The main industrial use of this protein is the hydrolysis of lactose in milk in a cooling conditions. Synthesis of galactooligosaccharides, which are mostly used as a prebiotics added to some foods or available as dietary supplements, is only one...
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Impact of high-pressure processing on the bioactive compounds of milk - A comprehensive review
PublicationHigh-pressure processing (HPP) is a promising alternative to thermal pasteurization. Recent studies highlighted the effectivity of HPP (400–600 MPa and exposure times of 1–5 min) in reducing pathogenic microflora for up to 5 logs. Analysis of modern scientific sources has shown that pressure affects the main components of milk including fat globules, lactose, casein micelles. The behavior of whey proteins under HPP is very important...
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Cold-Active beta-Galactosidases: Sources, Biochemical Properties and Their Biotechnological Potential
Publicationbeta-D-Galactosidases have been studied extensively in terms of their application to a variety of industrial technologies. To date, considerable research efforts have been devoted to characterization of new cold-active beta-D-galactosidases which were isolated directly from selected species of bacteria and yeasts, as well as with the use of metagenomic approaches. This chapter will provide a review of current research towards cold-active...
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THE GENE CLONING, OVEREXPRESSION, PURIFICATION AND BIOCHEMICAL CHARACTERISATION OF A NEW COLD-ADAPTED β–GALACTOSIDASE FROM ARTHROBACTER SP. VII-4
PublicationINTRODUCTION. β-Galactosidase [EC 3.2.1.23] is an enzyme that catalyzes the hydrolysis of O-glycosidic linkages in galactosides. It is commercially used in dairy industry for the production of milk with reduced lactose content. Potentially, the best method for lactose removal under cooling conditions should be carried out with a cold-adapted enzyme. AIM. The aim of this study was to determine the taxonomic affiliation of the isolate...
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Meiothermus ruber cells as β-galactosidase activity biocatalyst
PublicationThe current study allowed to establish the possibility of using whole cells of thermophilic bacteria Meiothermus ruber as a biocatalyst with β-galactosidase activity. β-galactosidases are used for hydrolysis of lactose as well as for oligosaccharides synthesis. The advantages of using whole bacterial cells catalysis is not only elimination of tedious, expensive protein isolation and/or purification but also stabilization of enzymes...
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A new cold-active β-galactosidase from Arthrobacter sp. S3* - gene cloning, overexpression, purification and properties
PublicationA psychrotrophic bacterium producing a cold-active β-galactosidase was isolated from Spitsbergen soil and classified as Arthrobacter sp. S3*. The gene encoding β-galactosidase was isolated from the genomic DNA library, sequenced, cloned, expressed in Escherichia coli, purified by ion exchange chromatography and characterized. The Arthrobaster sp. S3* β-galactosidase is a homotrimeric enzyme composed of 74,4 kDa subunits. It is...
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Structural studies of a cold-adapted dimeric Beta-D-galactosidase from Paracoccus sp. 32d
PublicationThe crystal structure of a novel dimeric [beta]-D-galactosidase from Paracoccus sp. 32d (Par[beta]DG) was solved in space group P212121 at a resolution of 2.4 Å by molecular replacement with multiple models using the BALBES software. This enzyme belongs to glycoside hydrolase family 2 (GH2), similar to the tetrameric and hexameric [beta]-D-galactosidases from Escherichia coli and Arthrobacter sp. C2-2, respectively. It is the second...
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Beta-galactosidase activity of Meiothermus ruber cells
PublicationFreeze-dried cells of Meiothermus ruber catalyses cleavage of o-nitrophenyl-b-D-galactopiranoside (oNPb-gal) and conversion of lactose into glucose and galactose. The permeabilization with 2%toluene,20%ethanol and 20%acetone increased enzymatic activity from 74.87 U/g of lyophilized cells up to 129.44,114.38 and 90.19 U/g,respectively. Ethanol was an effective permeabilizing agent and its efficiency was dependent on the concentration,...
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Characterization of immobilized Escherichia coli cells transformed by β-galactosidase gene from Pyrococcus woesei
PublicationThermostable β-galactosidase from Escherichia coli transformant containing theenzyme gene from Pyrococcus woesei was immobilized on alginate gel.The benefits of using whole bacterial cells not only exclude expensive, laborious proteinisolation and purification but also stabilize enzymes by cytosol components. Increase inproductivity of enzyme can be achieved by cells permeabilization. To increase permeability ofcytoplasmic membrane...
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Indirect Determination of MCPD Fatty Acid Esters in Lipid Fractions of Commercially Available Infant Formulas for the Assessment of Infants’ Health Risk
PublicationMCPD esters are intensively investigated food lipid contaminants for over a decade. Concern related to their presence in various types of food products is related to the fact that possible free MCPD release from its esterified form during digestion may lead to elevated daily intake of these toxicants.Special attention should be devoted into powdered infant formulas, which contain significant amounts of refined vegetable oils, likely...
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Identyfikacja i izolacja genu kodującego zaadaptowaną do zimna β-galaktozydazę Paracoccus sp. = Identification and izolation of the gene encoding cold-active β-galactosidase from paracoccus sp.
PublicationZaprezentowane badania były prowadzone u eehi wyizolowania ze środo¬wiska organizmu psychrofilnego, zdolnego do hydrolizy laktozy w niskiej tempe¬raturze, oraz zidentyfikowania genu kodującego (i-galaktozydazę zaadaptowaną do zimna.Poszukiwan gen został w izolowany z psychrofilnego szczepu autarkicz¬nego Paracoccus sp. 321). Na podstawie sekwencji nukleotydowej genu kodują¬cego fS-galaktozdaze ustalono skład aminokwasów),...
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In Situ Random Microseeding and Streak Seeding Used for Growth of Crystals of Cold-Adapted beta-D-Galactosidases: Crystal Structure of betaDG from Arthrobacter sp. 32cB
PublicationThere is an increasing demand for cold-adapted enzymes in a wide range of industrial branches. Nevertheless, structural information about them is still scarce. The knowledge of crystal structures is important to understand their mode of action and to design genetically engineered enzymes with enhanced activity. The most difficult task and the limiting step in structural studies of cold-adapted enzymes is their crystallization,...
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An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography–tandem mass spectrometry
PublicationThe influence of sucrose combustion products on smoking and nicotine addiction is still controversial because the presence of the sucrose may be treated as a source of aldehydes and organic acids. In e-liquids used as refills for electronic cigarettes, which are made primarily of poly(propylene glycol), glycerine and ethanol, sucrose may be present at trace levels, and its impact on mainstream smoke formation, and hence on human...
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Investigation of sweet substances of different molecular structure by potentiometric taste sensor with all solid state electrodes
PublicationA five channel potentiometric taste sensor consisting of an array of All Solid State Electrodes (ASSESs) with different lipid-polymer membranes has been developed. The electrodes are constructed of glassy carbon discs with electrochemically deposited poly(3,4-ethylenedioxythiophene) (PEDOT) acting as ion to electron transducer. The outer layer of the electrode is lipid-polymer membrane. Lipid substances immobilized in PVC membranes...