Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
1.
Antioxidants (Basel) ; 12(10)2023 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-37891919

RESUMEN

Herein, we report on the production, characterization, and antioxidant power assessment of carotenoids from the haloarchaeon Halorhabdus utahensis. It was grown at 37 °C and 180 rpm agitation in halobacteria medium supplemented with glucose, fructose, and xylose, each at concentrations of 0.2%, 1%, and 2%, and the carotenoid yield and composition were investigated. The microorganism produced the carotenoids under all the conditions tested, and their amount followed the order glucose < xylose < fructose. The highest yield was achieved in 2% fructose growth medium with 550.60 ± 7.91 µg/g dry cell and 2428.15 ± 49.33 µg/L. Separation and identification of the carotenoids were performed by RP-HPLC and HPLC/APCI-ITMSn. Bacterioruberin was the main carotenoid detected and accounted for 60.6%, 56.4%, and 58.9% in 2% glucose, 1% xylose, and 2% fructose extracts, respectively. Several geometric isomers of bacterioruberin were distinguished, and representatives of monoanhydrobacterioruberin, and bisanhydrobacterioruberin were also detected. The assignment to cis-isomers was attempted through analysis of the UV/Vis spectra, intensity of cis peaks, and spectral fine structures. The extracts exhibited superoxide scavenging activity higher than butylhydroxytoluene, ascorbic acid, and Trolox, selected as antioxidant references. The anti-hyaluronidase capacity was investigated, and the 2% fructose extract showed the highest activity reaching 90% enzyme inhibition with 1.5 µg. The overall data confirm that Hrd. utahensis can be regarded as an interesting source of antioxidants that can find applications in the food and cosmetic sectors.

2.
Molecules ; 27(8)2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35458774

RESUMEN

In the current study, we determined the antioxidant properties of "Greco" grape cane extracts, a typical cultivar of southern Italy. We also explored the anticancer activity of the polyphenol-rich fraction of the extract on head and neck squamous carcinoma cells (HNSCC) and investigated the underlying mechanism. Aqueous extracts were prepared at different pHs and extraction times and the total phenolic and reducing sugar contents were estimated. Radical Scavenging Activity (RSA), Ferric Reducing Antioxidant Power (FRAP), and Total Antioxidant Capacity (TAC) of the extracts were measured. A polyphenol-rich fraction, accounting for 6.7% by weight and characterized mainly by procyanidins and stilbenoids, was prepared from the extract obtained at pH 7 for 60 min. We demonstrated that the extract exerted a cytotoxic effect on HNSCC cell lines by inducing cell cycle arrest via cyclin downregulation and p21 upregulation, and by triggering apoptosis through caspase cascade activation, PARP-1 cleavage, and an increase in the Bax/Bcl-2 ratio. We furnished evidence that the polyphenol-rich fraction played the major role in the anticancer activity of the extract. These outcomes highlighted grape canes from the "Greco" cultivar as a valuable source of polyphenols that may represent good candidates for the design of innovative adjuvant therapies in the treatment of HNSCC.


Asunto(s)
Neoplasias de Cabeza y Cuello , Vitis , Antioxidantes/química , Antioxidantes/farmacología , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Humanos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Polifenoles/farmacología , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico
3.
Foods ; 9(12)2020 Dec 03.
Artículo en Inglés | MEDLINE | ID: mdl-33287134

RESUMEN

Fresh figs are very sensitive to microbial spoilage, even in cold storage conditions. Thus, fresh figs are high perishable products during postharvest with microbiological decay that induces an unpleasant taste and smell due to rot, and suitable conservation methods must therefore be applied. The fruit usually is consumed fresh locally, dried, or preserved longer term in other transformed forms. A sustainable approach to extend the shelf-life of figs can be constituted by application of an edible coating able to maintain the quality of the fruit during storage. A comparison between fresh figs in a commercial preservation system, with the figs preserved in an edible coating, and an active edible coating to preserve their quality characteristics was carried out. The coating efficacy was enhanced with the addition of pomegranate peel extract at two different concentrations. The inclusion of a component with high antioxidant activity in an edible coating proved to be an excellent method for preserving the quality of this highly perishable fruit. The application of natural products, obtained from renewable sources, represents a simple and economic strategy, but also a tool capable of preserving the quality of the fruit during the postharvest storage, which is often consumed in production areas due to shelf-life problems.

4.
Int J Food Sci Nutr ; 71(4): 410-423, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31544542

RESUMEN

Total phenolic content and antioxidant activity of polar extracts of edible resources from Fedora hemp cultivar (Cannabis sativa L.), namely seed, flour and oil, were evaluated. The main components in the polar extracts were identified using HPLC-DAD and HPLC-ESI-MS/MS. As expected, the molecular profile of components from seeds and flour was strictly similar, dominated by N-trans-caffeoyltyramine. The profile of oil polar extracts contained hydroxycinnamic acid derivatives and cannabinoids at lower extent. While the extracts from hemp seed and flour did not interfere with growth of Caco-2 and HT-29 cell, the one from oil (150 µg/mL) significantly reduced cell viability after 24 h of treatment. This effect was associated with the activation of apoptotic cell death and was independent from the antioxidant capacity of the oil polar extract. Notably, HT-29 cells differentiated with sodium butyrate were not sensitive to the cytotoxic effect of the oil extract.


Asunto(s)
Antioxidantes/farmacología , Cannabis/química , Neoplasias Colorrectales/tratamiento farmacológico , Extractos Vegetales/farmacología , Apoptosis/efectos de los fármacos , Células CACO-2 , Cannabinoides/análisis , Proliferación Celular/efectos de los fármacos , Harina/análisis , Células HT29 , Humanos , Fenoles , Extractos Vegetales/química , Aceites de Plantas/química , Semillas/química , Espectrometría de Masas en Tándem
5.
J Food Sci Technol ; 56(11): 4982-4991, 2019 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-31741522

RESUMEN

Non-Saccharomyces yeasts are metabolically active during grape must fermentations and can contribute with enzymes and metabolites to enhance the complexity and to define the final wine aroma. Nowadays, the use of non-Saccharomyces yeasts in combination with Saccharomyces cerevisiae is a state-of-the art strategy to improve wine composition and/or wine sensory properties. The present paper deals with the new yeast strains of Metschnikowia fructicola and S. cerevisiae, that were selected as representatives of the yeast microbiota isolated from grapes and grape juice of Aglianico cultivar. S. cerevisiae was utilized both as single strain starter and in combination with M. fructicola in experimental fermentations of Aglianico must. The dynamic of yeast populations was evaluated during the fermentation process analyzing the wine volatile compounds profile. The volatile compounds were identified by SPME-GC/MS. The results, showed that the multiple indigenous yeast starter was able to modulate the volatile compounds profiles and improve the aromatic complexity of wine, with a higher content of esters and terpenes.

6.
Molecules ; 24(18)2019 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-31546790

RESUMEN

In this study, chestnut shells (CS) were used in order to obtain bioactive compounds through different extraction procedures. The aqueous extracts were chemically characterized. The highest extraction yield and total phenolic content was obtained by conventional liquid extraction (CLE). Gallic and protocatechuic acids were the main simple phenols in the extract, with 86.97 and 11.20 mg/g chestnut shells dry extract (CSDE), respectively. Six tumor cell lines (DU 145, PC-3, LNCaP, MDA-MB-231, MCF-7, and HepG2) and one normal prostate epithelial cell line (PNT2) were exposed to increasing concentration of CSDE (1-100 µg/mL) for 24 h, and cell viability was evaluated using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide MTT assay. A reduced rate in cell viability was observed in DU 145, PC-3, LNCaP, and MCF-7 cells, while viability of the other assessed cells was not affected, except for PNT2 cells at a concentration of 100 µg/mL. Furthermore, CSDE-at concentrations of 55.5 and 100 µg/mL-lead to a significant increase of apoptotic cells in DU 145 cells of 28.2% and 61%, respectively. In conclusion, these outcomes suggested that CS might be used for the extraction of several polyphenols that may represent good candidates for alternative therapies or in combination with current chemotherapeutics.


Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Fagaceae/química , Extractos Vegetales/farmacología , Agua/química , Línea Celular Tumoral , Humanos , Fenoles/análisis
7.
Int J Biol Macromol ; 122: 1224-1234, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30219517

RESUMEN

An intracellular ß-xylosidase (AbXyl), from the thermoalkaline Anoxybacillus sp. 3M, was purified and characterized. The homodimeric enzyme (140 kDa) was optimally active at 65 °C and pH 5.5, exhibited half life of 10 h at 60 °C, 78 and 88% residual activity after 24 h, at pH 4.5 and 8.0, respectively. Fe2+, Cu2+, Al3+, Ag+ and Hg2+ inhibited the enzyme; the activity was moderately stimulated by SDS and not influenced by ß-mercaptoethanol. In the presence of p-nitrophenyl-ß-d-xylopyranoside, AbXyl exhibited Km of 0.19 mM, Kcat of 453.29 s-1, Kcat Km-1 of 2322 s-1 mM and was moderately influenced by xylose (Ki 21.25 mM). The enzyme hydrolyzed xylo-oligomers into xylose and catalyzed transxylosilation reactions also in presence of alcohols as acceptors, producing xylo-oligosaccharides and alkyl-xylosides. Finally AbXyl was applied towards a statistically optimized process of brewery's spent grain bioconversion, highlighting the important role of this biocatalyst in reaching high yields of fermentable sugars.


Asunto(s)
Agricultura , Anoxybacillus/enzimología , Carbohidratos/química , Residuos Industriales , Xilosidasas/metabolismo , Anoxybacillus/citología , Inhibidores Enzimáticos/farmacología , Concentración de Iones de Hidrógeno , Hidrólisis , Espacio Intracelular/enzimología , Especificidad por Sustrato , Temperatura , Xilosidasas/antagonistas & inhibidores
8.
Molecules ; 24(1)2018 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-30591638

RESUMEN

A series of chemical and biochemical parameters of edible hemp resources (seeds, oil, and flour) from the monoecious EU registered hemp genotype Fedora, was determined, including fatty acid profile, phytosterol composition, total phenolics, antioxidant activity, macro- and micro-elements. The fatty acid ω-3/ω-6 approached the nutritionally optimal 3/1 ratio. ß-sitosterol and other phytosterols sterols dominated the unsaponifiable fraction. Hemp seeds, flour, and oil contained 767 ± 41, 744 ± 29, and 21 ± 5 mg GAE kg-1 total polyphenols, respectively. The antioxidant potential of Fedora flour and seeds, evaluated through the DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay, was higher than that of oil. K and Mg were the most abundant macro-elements, particularly in flour, while the concentration of trace elements was Fe > Cu > Ni > Mn. The presence of an array of bioactive compound candidate Fedora products as health-promoting food matrices. The ATR-FTIR spectra of hemp-derived products indicated the proximate composition of macro-nutrients.


Asunto(s)
Cannabis/química , Harina/análisis , Aceites de Plantas/química , Plantas Comestibles/química , Semillas/química , Antioxidantes/análisis , Minerales/análisis , Polifenoles/análisis , Saponinas/análisis , Espectroscopía Infrarroja por Transformada de Fourier
9.
Biopolymers ; 109(10): e23118, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29608017

RESUMEN

In this work, a new exploitation of the thermostable ß-glycosidase from Sulfolobus solfataricus expressed in Saccharomyces cerevisiae to create functional foods for low lactose diets was evaluated. For this purpose, the lactose hydrolysis reaction using immobilized and soluble enzymes was investigated. Activity and stability at different conditions of pH and temperature were tested. The immobilization process had a big impact on the catalysis performance, leading to an enhancement of the enzymatic reaction rate on lactose, as demonstrated by the increasing of 2 and 2.5 folds of Kcat and Kcat /KM , respectively. Moreover, the maximal activity for the immobilized form was referred at pH 6.5 instead of 7.0, leading to an improvement of the catalytic performance at milk pHs. Although the soluble enzyme was already weakly inhibited by the reaction products, the immobilization further reduced the inhibitory action of glucose increasing the Ki from 96.7 to 110.4 mM. Finally, the immobilized enzyme showed high hydrolysis rate in whole milk that yielded 99% of lactose breakdown in 10 and 30 min at 60 and 40°C, respectively. These results support the application of the immobilized ß-glycosidase for the development of new functional foods particularly suitable to the alleviation of lactose intolerance.


Asunto(s)
Glicósido Hidrolasas/metabolismo , Lactosa/metabolismo , Leche/química , Temperatura , Animales , Bovinos , Quitosano/química , Estabilidad de Enzimas , Enzimas Inmovilizadas/metabolismo , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Sulfolobus/enzimología
10.
Nat Prod Res ; 32(9): 1022-1032, 2018 May.
Artículo en Inglés | MEDLINE | ID: mdl-28920445

RESUMEN

The underutilised forest and industrial biomass of Castanea sativa (Mill.) is generally discarded during post-harvest and food processing, with high impact on environmental quality. The searching on alternative sources of natural antioxidants from low-cost supplies, by methods involving environment-friendly techniques, has become a major goal of numerous researches in recent times. The aim of the present study was the set-up of a biomolecules extraction procedure from chestnut leaves, burs and shells and the assessing of their potential antioxidant activity. Boiling water was the best extraction solvent referring to polyphenols from chestnut shells and burs, whereas the most efficient for leaves resulted 60% ethanol at room temperature. Greatest polyphenol contents were 90.35, 60.01 and 17.68 mg gallic acid equivalents g-1 in leaves, burs and shells, respectively. Moreover, flavonoids, tannins and antioxidant activity were assessed on the best extract obtained from each chestnut by-product.


Asunto(s)
Antioxidantes/farmacología , Fraccionamiento Químico/métodos , Fagaceae/química , Extractos Vegetales/farmacología , Antioxidantes/química , Etanol/química , Flavonoides/análisis , Manipulación de Alimentos , Nueces/química , Extractos Vegetales/química , Hojas de la Planta/química , Polifenoles/análisis , Polifenoles/aislamiento & purificación , Solventes/química , Taninos/análisis , Temperatura
11.
Extremophiles ; 21(5): 933-945, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28803263

RESUMEN

Haloterrigena turkmenica was able to synthesize carotenoids when grown in halobacteria medium. These molecules have antioxidant properties and find application in food, cosmetic, and pharmaceutical fields. The carotenoids were extracted with methanol, separated by RP-HPLC, and identified by mass spectrometry and UV/Vis spectra analyses. The C50 carotenoids were the main pigments, and C30, C40, and C51 carotenoids were also detected. Seven geometric isomers were distinguished for bacterioruberin, monoanhydrobacterioruberin, and bisanhydrobacterioruberin. The assignment to a specific isomer was tentatively attempted through the analysis of the corresponding UV/Vis spectrum, the intensity of the cis peak, and its spectral fine structure. Lycopene, phytoene, and lycopersene were among the minor carotenoids further identified. The extract displayed antioxidant power higher than alpha-tocopherol, butylhydroxytoluene, and ascorbic acid used as reference compounds. Our studies identified for the first time seven geometric isomers of bacterioruberin derivatives and 30 carotenoids in a haloarchaeon.


Asunto(s)
Antioxidantes/química , Carotenoides/química , Halobacteriaceae/química , Antioxidantes/farmacología , Carotenoides/farmacología , Ambientes Extremos , Oxidación-Reducción , Tolerancia a la Sal
12.
J Agric Food Chem ; 64(48): 9172-9179, 2016 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-27933987

RESUMEN

Italy is one of the world's major kiwifruit producers and exporters with orchards located in different areas from the north to the south of the peninsula. This study sought to investigate for the first time the possible influence of the geographical location of kiwifruit orchards on some fruit components, selected because of their involvement in beneficial or negative effects on human health. The fruits harvested in 16 Italian areas were analyzed, and the results obtained show that the observed variations of the relative amounts of total proteins, kiwellin, the major allergen actinidin, ascorbate, polyphenols, and superoxide dismutase (SOD)-like activity seem not to be related to the geographical location of the orchards. In contrast, the high concentration of the nutraceutical peptide kissper seems to have some relationship with the cultivation area. In fact, its amount is much higher in the fruits from the Lazio region, thus providing added value to these kiwifruits.


Asunto(s)
Actinidia/química , Frutas/química , Extractos Vegetales/química , Proteínas de Plantas/química , Alérgenos/química , Antígenos de Plantas/química , Antioxidantes/química , Ácido Ascórbico/química , Cisteína Endopeptidasas/química , Geografía , Italia , Polifenoles/química , Superóxido Dismutasa/química
13.
Biotechnol Biofuels ; 9: 154, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27453729

RESUMEN

BACKGROUND: Biofuels production from plant biomasses is a complex multi-step process with important economic burdens. Several biotechnological approaches have been pursued to reduce biofuels production costs. The aim of the present study was to explore the production in tobacco plastome of three genes encoding (hemi)cellulolytic enzymes from thermophilic and hyperthermophilic bacterium and Archaea, respectively, and test their application in the bioconversion of an important industrially pretreated biomass feedstock (A. donax) for production of second-generation biofuels. RESULTS: The selected enzymes, endoglucanase, endo-ß-1,4-xylanase and ß-glucosidase, were expressed in tobacco plastome with a protein yield range from 2 % to more than 75 % of total soluble proteins (TSP). The accumulation of endoglucanase (up to 2 % TSP) gave altered plant phenotypes whose severity was directly linked to the enzyme yield. The most severe seedling-lethal phenotype was due to the impairment of plastid development associated to the binding of endoglucanase protein to thylakoids. Endo-ß-1,4-xylanase and ß-glucosidase, produced at very high level without detrimental effects on plant development, were enriched (fourfold) by heat treatment (105.4 and 255.4 U/mg, respectively). Both plastid-derived biocatalysts retained the main features of the native or recombinantly expressed enzymes with interesting differences. Plastid-derived xylanase and ß-glucosidase resulted more thermophilic than the E. coli recombinant and native counterpart, respectively. Bioconversion experiments, carried out at 50 and 60 °C, demonstrated that plastid-derived enzymes were able to hydrolyse an industrially pretreated giant reed biomass. In particular, the replacement of commercial enzyme with plastid-derived xylanase, at 60 °C, produced an increase of both xylose recovery and hydrolysis rate; whereas the replacement of both xylanase and ß-glucosidase produced glucose levels similar to those observed with the commercial cocktails, and xylose yields always higher in the whole 24-72 h range. CONCLUSIONS: The very high production level of thermophilic and hyperthermophilic enzymes, their stability and bioconversion efficiencies described in this study demonstrate that plastid transformation represents a real cost-effective production platform for cellulolytic enzymes.

14.
Int J Biol Macromol ; 92: 174-184, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27377461

RESUMEN

An extracellular halophilic alpha-amylase (AmyA) was produced by the haloarchaeon Haloterrigena turkmenica grown in medium enriched with 0.2% (w/v) starch. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion chromatography (SEC) analyses showed a major band at 66.0kDa and a peak of 54.0kDa, respectively. Analysis of tryptic fragments of the protein present in the major SDS-PAGE band by nano-LC-ESI-MS/MS led to identification of the alpha-amylase catalytic region, encoded by the htur2110 gene, as the protein possessing the described activity. Optimal values for activity were 55°C, pH 8.5 and 2M NaCl, and high thermostability was showed at 55°C and 3M NaCl. AmyA activity was enhanced by Triton X-100 and was not influenced by n-hexane and chloroform. Starch hydrolysis produced different oligomers with maltose as the smallest end-product. The efficiency of AmyA in degrading starch contained in agronomic residues was tested in grape cane chosen as model substrate. Preliminary results showed that starch was degraded making the enzyme a potential candidate for utilization of agro-industrial waste in fuel and chemicals production. AmyA is one of the few investigated amylases produced by haloarchaea, and the first alpha-amylase described among microorganisms belonging to the genus Haloterrigena.


Asunto(s)
Archaea/enzimología , alfa-Amilasas/aislamiento & purificación , alfa-Amilasas/metabolismo , Secuencia de Aminoácidos , Archaea/crecimiento & desarrollo , Calcio/farmacología , Cromatografía Líquida de Alta Presión , Ácido Edético/farmacología , Electroforesis en Gel de Poliacrilamida , Concentración de Iones de Hidrógeno , Hidrólisis , Iones , Compuestos Orgánicos/farmacología , Cloruro de Sodio/farmacología , Solventes , Almidón/metabolismo , Especificidad por Sustrato/efectos de los fármacos , Tensoactivos/farmacología , Temperatura , alfa-Amilasas/química
15.
Molecules ; 21(3): 319, 2016 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-27005599

RESUMEN

Many studies have evidenced that the phenolic components from flaxseed (FS) oil have potential health benefits. The effect of the phenolic extract from FS oil has been evaluated on two human breast cancer cell lines, MCF7 and MDA-MB231, and on the human non-cancerous breast cell line, MCF10A, by SRB assay, cellular death, cell cycle, cell signaling, lipid peroxidation and expression of some key genes. We have evidenced that the extract shows anti-proliferative activity on MCF7 cells by inducing cellular apoptosis, increase of the percentage of cells in G0/G1 phase and of lipid peroxidation, activation of the H2AX signaling pathway, and upregulation of a six gene signature. On the other hand, on the MDA-MB2131 cells we verified only an anti-proliferative activity, a weak lipid peroxidation, the activation of the PI3K signaling pathway and an up-regulation of four genes. Overall these data suggest that the extract has both cytotoxic and pro-oxidant effects only on MCF7 cells, and can act as a metabolic probe, inducing differences in the gene expression. For this purpose, we have performed an interactomic analysis, highlighting the existing associations. From this approach, we show that the phenotypic difference between the two cell lines can be explained through their differential response to the phenolic extract.


Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Aceite de Linaza/administración & dosificación , Apoptosis/efectos de los fármacos , Neoplasias de la Mama/patología , Femenino , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Histonas/biosíntesis , Humanos , Peroxidación de Lípido/efectos de los fármacos , Células MCF-7 , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos
16.
Appl Microbiol Biotechnol ; 100(2): 613-23, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26403921

RESUMEN

We have isolated a novel exopolysaccharide (EPS) produced by the extreme halophilic archaeon Haloterrigena turkmenica. Some features, remarkable from an industrial point of view, such as emulsifying and antioxidant properties, were investigated. H. turkmenica excreted 20.68 mg of EPS per 100 ml of culture medium when grown in usual medium supplemented with glucose. The microorganism excreted the biopolymer mainly in the middle exponential growth phase and reached the maximal production in the stationary phase. Analyses by anion exchange chromatography and SEC-TDA Viscotek indicated that the EPS was composed of two main fractions of 801.7 and 206.0 kDa. It was a sulfated heteropolysaccharide containing glucose, galactose, glucosamine, galactosamine, and glucuronic acid. Studies performed utilizing the mixture of EPS anionic fractions showed that the biopolymer had emulsifying activity towards vegetable oils comparable or superior to that exhibited by the controls, moderate antioxidant power when tested with 2,2'-diphenyl-1-picrylhydrazyl (DPPH(·)), and moisture-retention ability higher than hyaluronic acid (HA). The EPS from H. turkmenica is the first exopolysaccharide produced by an archaea to be characterized in terms of properties that can have potential biotechnological applications.


Asunto(s)
Halobacteriales/metabolismo , Polisacáridos/biosíntesis , Polisacáridos/química , Antioxidantes/química , Antioxidantes/metabolismo , Biotecnología , Compuestos de Bifenilo/farmacología , Medios de Cultivo/química , Emulsiones , Galactosa/metabolismo , Glucosa/metabolismo , Halobacteriales/química , Ácido Hialurónico/metabolismo , Picratos/farmacología
17.
Biomed Res Int ; 2015: 951871, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26634214

RESUMEN

An enzymatic mixture of cellulases and xylanases was produced by Pleurotus ostreatus using microcrystalline cellulose as inducer, partially characterized and tested in the statistical analysis of Arundo donax bioconversion. The Plackett-Burman screening design was applied to identify the most significant parameters for the enzymatic hydrolysis of pretreated A. donax. As the most significant influence during the enzymatic hydrolysis of A. donax was exercised by the temperature (°C), pH, and time, the combined effect of these factors in the bioconversion by P. ostreatus cellulase and xylanase was analyzed by a 3(3) factorial experimental design. It is worth noting that the best result of 480.10 mg of sugars/gds, obtained at 45 °C, pH 3.5, and 96 hours of incubation, was significant also when compared with the results previously reached by process optimization with commercial enzymes.


Asunto(s)
Carbohidratos/síntesis química , Celulasas/química , Celulosa/química , Endo-1,4-beta Xilanasas/química , Pleurotus/enzimología , Poaceae/química , Carbohidratos/aislamiento & purificación , Técnicas Químicas Combinatorias/métodos , Extractos Vegetales/química
18.
J Chem Technol Biotechnol ; 90(3): 573-581, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25866429

RESUMEN

BACKGROUND: Cellulases and xylanases are the key enzymes involved in the conversion of lignocelluloses into fermentable sugars. Western Ghat region (India) has been recognized as an active hot spot for the isolation of new microorganisms. The aim of this work was to isolate new microorganisms producing cellulases and xylanases to be applied in brewer's spent grain saccharification. RESULTS: 93 microorganisms were isolated from Western Ghat and screened for the production of cellulase and xylanase activities. Fourteen cellulolytic and seven xylanolytic microorganisms were further screened in liquid culture. Particular attention was focused on the new isolate Bacillus amyloliquefaciens XR44A, producing xylanase activity up to 10.5 U mL-1. A novel endo-1,4-beta xylanase was identified combining zymography and proteomics and recognized as the main enzyme responsible for B. amyloliquefaciens XR44A xylanase activity. The new xylanase activity was partially characterized and its application in saccharification of brewer's spent grain, pretreated by aqueous ammonia soaking, was investigated. CONCLUSION: The culture supernatant of B. amyloliquefaciens XR44A with xylanase activity allowed a recovery of around 43% xylose during brewer's spent grain saccharification, similar to the value obtained with a commercial xylanase from Trichoderma viride, and a maximum arabinose yield of 92%, around 2-fold higher than that achieved with the commercial xylanase. © 2014 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

19.
Food Chem ; 184: 220-8, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-25872448

RESUMEN

Evaluation of phenolic profile, antioxidant power, and protective capacity against oxidation of red blood cells (RBCs) of olive oil phenolic extracts (OOPEs) from several Italian varieties were studied. Phenolic profiles, and quantification of seven selected bioactive compounds were performed by RP-HPLC. OOPEs exhibited high antioxidant activity, and this capacity was positively related to their phenolic amount. In particular, OOPE5 (cv Gentile di Larino, Molise region) displayed the highest phenolic and ortho-diphenolic content as well as the strongest scavenging activity determined using 2,2'-diphenyl-1-picrylhydrazyl (DPPH) (87% DPPH inhibition). Protective capacity against stressed RBCs was investigated through the evaluation of methemoglobin (MetHb) and malondialdehyde (MDA) levels. OOPE5 was the most active against methemoglobin production (53.7% reduction), whereas OOPE1 (cv Lavagnina, Liguria region) showed the highest protection toward malondialdehyde (83.3% reduction). Overall the selected oils showed qualitative and quantitative differences in phenol composition, and this variability influenced their protective effect against oxidative damages.


Asunto(s)
Aceite de Oliva/química , Fenoles/análisis , Aceites de Plantas/química , Antioxidantes/química , Humanos , Italia , Estrés Oxidativo
20.
World J Microbiol Biotechnol ; 31(4): 633-48, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25687227

RESUMEN

An extracellular thermo-alkali-stable and cellulase-free xylanase from Geobacillus thermodenitrificans A333 was purified to homogeneity by ion exchange and size exclusion chromatography. Its molecular mass was 44 kDa as estimated in native and denaturing conditions by gel filtration and SDS-PAGE analysis, respectively. The xylanase (GtXyn) exhibited maximum activity at 70 °C and pH 7.5. It was stable over broad ranges of temperature and pH retaining 88 % of activity at 60 °C and up to 97 % in the pH range 7.5-10.0 after 24 h. Moreover, the enzyme was active up to 3.0 M sodium chloride concentration, exhibiting at that value 70 % residual activity after 1 h. The presence of other metal ions did not affect the activity with the sole exceptions of K(+) that showed a stimulating effect, and Fe(2+), Co(2+) and Hg(2+), which inhibited the enzyme. The xylanase was activated by non-ionic surfactants and was stable in organic solvents remaining fully active over 24 h of incubation in 40 % ethanol at 25 °C. Furthermore, the enzyme was resistant to most of the neutral and alkaline proteases tested. The enzyme was active only on xylan, showing no marked preference towards xylans from different origins. The hydrolysis of beechwood xylan and agriculture-based biomass materials yielded xylooligosaccharides with a polymerization degree ranging from 2 to 6 units and xylobiose and xylotriose as main products. These properties indicate G. thermodenitrificans A333 xylanase as a promising candidate for several biotechnological applications, such as xylooligosaccharides preparation.


Asunto(s)
Proteínas Bacterianas/química , Geobacillus/enzimología , Glucuronatos/metabolismo , Oligosacáridos/metabolismo , Xilosidasas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/aislamiento & purificación , Proteínas Bacterianas/metabolismo , Clonación Molecular , Estabilidad de Enzimas , Geobacillus/química , Geobacillus/genética , Concentración de Iones de Hidrógeno , Peso Molecular , Especificidad por Sustrato , Temperatura , Xilosidasas/genética , Xilosidasas/aislamiento & purificación , Xilosidasas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA