Aspergillus carbonarius

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P V Martinezculebras - One of the best experts on this subject based on the ideXlab platform.

  • effect of oxidant stressors and phenolic antioxidants on the ochratoxigenic fungus Aspergillus carbonarius
    Journal of the Science of Food and Agriculture, 2016
    Co-Authors: Luis Gonzalezcandelas, P V Martinezculebras, Ana Cresposempere, Cristina Selmalazaro, Jeffrey D Palumbo
    Abstract:

    BACKGROUND There are few studies dealing with the relationship between oxidative stress and ochratoxin A (OTA) biosynthesis. In this work, we analyzed the effect of the oxidant stressor menadione and the antioxidants 3,5-di-tert-butyl-4-hydroxytoluene (BHT), catechin, resveratrol and a polyphenolic extract on growth, generation of reactive oxygen species (ROS), OTA production and gene expression of antioxidant enzymes of Aspergillus carbonarius. RESULTS Exposure to menadione concentrations higher than 20 µmol L−1 led to increases in ROS and OTA levels and a decrease in growth rate. Exposure to 2.5–10 mmol L−1 BHT also led to higher ROS and OTA levels, although growth rate was only affected above 5 mmol L−1. Naturally occurring concentrations of catechin, resveratrol and polyphenolic extract barely affected growth rate, but they produced widely different effects on OTA production level depending on the antioxidant concentration used. In general, gene expression of antioxidant enzymes superoxide dismutase (SOD) and peroxiredoxin (PRX) was downregulated after exposure to oxidant and antioxidant concentrations that enhanced OTA production level. CONCLUSION Aspergillus carbonarius responds to oxidative stress, increasing OTA production. Nevertheless, the use of naturally occurring concentrations of antioxidant phenolic compounds to reduce oxidative stress is not a valid approach by itself for OTA contamination control in grapes. © 2015 Society of Chemical Industry

  • the loss of the inducible Aspergillus carbonarius mfs transporter mfsa leads to ochratoxin a overproduction
    International Journal of Food Microbiology, 2014
    Co-Authors: A Cresposempere, P V Martinezculebras, Luis Gonzalezcandelas
    Abstract:

    Ochratoxin A (OTA), a nephrotoxic compound produced by certain Aspergillus and Penicillium species, is one of the most abundant mycotoxins in food commodities. Aspergillus carbonarius is the main source of OTA in wine, grape juice and dried vine fruits. Although many studies have focused on OTA production by A. carbonarius, little is known about the genes related to OTA production and transport. We have found a transporter that belongs to the major facilitator superfamily (MfsA) which is highly expressed with a 102-fold induction in an ochratoxigenic A. carbonarius strain compared to a low OTA producer strain. The encoding mfsA gene shows similarity to the multidrug efflux transporter flu1 from Candida albicans. A high number of putative transcription factor binding sites involved in the response to stress were identified within the promoter of mfsA. Phenotypical analysis of ΔmfsA deletion mutants revealed that the loss of mfsA leads to a slight growth reduction and increased OTA production. We therefore hypothesize that MfsA could be a stress response transporter whose disruption could cause an increase in oxidative stress together with a stimulation of mycotoxin production.

  • characterization and disruption of the cipc gene in the ochratoxigenic fungus Aspergillus carbonarius
    Food Research International, 2013
    Co-Authors: A Cresposempere, P V Martinezculebras, Cristina Selmalazaro, Luis Gonzalezcandelas
    Abstract:

    Abstract Aspergillus carbonarius is considered the most important ochratoxin A (OTA) producing fungi among those causing OTA contamination in grapes and grape-derived products. CipC is a small protein with unknown function that was previously found to be highly up-regulated in an OTA producer strain of A. carbonarius in comparison to a non OTA producer strain. In this study, cipC was characterized and disrupted via Agrobacterium tumefaciens-mediated transformation in an ochratoxigenic A. carbonarius strain in order to study whether this gene has a role in OTA production. Sequence analysis indicated that the promoter region of cipC contains putative binding sites for transcription factors that regulate the utilization of nutrients, the stress response and detoxification processes, all factors that can influence mycotoxin biosynthesis. Although the ∆cipC mutant grew similarly to the wild type strain, the null mutant showed a much higher OTA production. Moreover, when A. carbonarius was grown under the oxidative stress conditions imposed by the presence of hydrogen peroxide, cipC gene expression was up-regulated. These results indicate that cipC is not directly involved in OTA biosynthesis, but sequence analysis of the A. carbonarius cipC gene promoter and the phenotype of the ΔcipC disrupted mutant suggests that CipC could be a stress response protein that would be up-regulated concomitantly with OTA production.

  • proteome analysis of the fungus Aspergillus carbonarius under ochratoxin a producing conditions
    International Journal of Food Microbiology, 2011
    Co-Authors: A Cresposempere, P V Martinezculebras
    Abstract:

    Aspergillus carbonarius is an important ochratoxin A producing fungus that is responsible for mycotoxin contamination of grapes and wine. In this study, the proteomes of highly (W04-40) and weakly (W04-46) OTA-producing A. carbonarius strains were compared to identify proteins that may be involved in OTA biosynthesis. Protein samples were extracted from two biological replicates and subjected to two dimensional gel electrophoresis analysis and mass spectrometry. Expression profile comparison (PDQuest software), revealed 21 differential spots that were statistically significant and showed a two-fold change in expression, or greater. Among these, nine protein spots were identified by MALDI-MS/MS and MASCOT database and twelve remain unidentified. Of the identified proteins, seven showed a higher expression in strain W04-40 (high OTA producer) and two in strain W04-46 (low OTA producer). Some of the identified amino acid sequences shared homology with proteins involved in regulation, amino acid metabolism, oxidative stress and sporulation. It is worth noting the presence of a protein with 126.5 fold higher abundance in strain W04-40 showing homology with protein CipC, a protein with unknown function related with pathogenesis and mycotoxin production by some authors. Variations in protein expression were also further investigated at the mRNA level by real-time PCR analysis. The mRNA expression levels from three identified proteins including CipC showed correlation with protein expression levels. This study represents the first proteomic analysis for a comparison of two A. carbonarius strains with different OTA production and will contribute to a better understanding of the molecular events involved in OTA biosynthesis.

  • genes differentially expressed by Aspergillus carbonarius strains under ochratoxin a producing conditions
    International Journal of Food Microbiology, 2010
    Co-Authors: A Cresposempere, Luis Gonzalezcandelas, P V Martinezculebras
    Abstract:

    Abstract Aspergillus carbonarius is an important ochratoxin A (OTA)-producing fungus that is responsible for toxin contamination of grapes and wine, coffee and cocoa. A suppression subtractive hybridization (SSH) approach was performed with two strains of A. carbonarius, antagonistic in their OTA-production ability, to identify genes whose expression is linked with the ability to produce OTA. BlastX analysis identified 109 differentially-expressed sequences putatively involved in the production of OTA, with significant similarities (Evalue

A Cresposempere - One of the best experts on this subject based on the ideXlab platform.

  • the loss of the inducible Aspergillus carbonarius mfs transporter mfsa leads to ochratoxin a overproduction
    International Journal of Food Microbiology, 2014
    Co-Authors: A Cresposempere, P V Martinezculebras, Luis Gonzalezcandelas
    Abstract:

    Ochratoxin A (OTA), a nephrotoxic compound produced by certain Aspergillus and Penicillium species, is one of the most abundant mycotoxins in food commodities. Aspergillus carbonarius is the main source of OTA in wine, grape juice and dried vine fruits. Although many studies have focused on OTA production by A. carbonarius, little is known about the genes related to OTA production and transport. We have found a transporter that belongs to the major facilitator superfamily (MfsA) which is highly expressed with a 102-fold induction in an ochratoxigenic A. carbonarius strain compared to a low OTA producer strain. The encoding mfsA gene shows similarity to the multidrug efflux transporter flu1 from Candida albicans. A high number of putative transcription factor binding sites involved in the response to stress were identified within the promoter of mfsA. Phenotypical analysis of ΔmfsA deletion mutants revealed that the loss of mfsA leads to a slight growth reduction and increased OTA production. We therefore hypothesize that MfsA could be a stress response transporter whose disruption could cause an increase in oxidative stress together with a stimulation of mycotoxin production.

  • ecophysiological characterization of Aspergillus carbonarius Aspergillus tubingensis and Aspergillus niger isolated from grapes in spanish vineyards
    International Journal of Food Microbiology, 2014
    Co-Authors: Esther Garciacela, A Cresposempere, V Sanchis, Antonio J Ramos, Sonia Marin
    Abstract:

    abstract Article history:Received 10 September 2013Received in revised form 25 November 2013Accepted 12 December 2013Available online 21 December 2013Keywords:Climate conditionsProbabilistic modelsMicrosatellitesOchratoxin ABlack aspergilli The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from differentagroclimatic regions of Spain. Growth characterization( interms of temperature and water activity requirements)of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium.A.tubingensis andA.niger showedhighermaximumtemperaturesforgrowth( N45 °Cversus40–42 °C),andlowerminimuma w requirements(0.83 a w versus 0.87 a w )thanA.carbonarius.Nodifferencesingrowthboundariesdueto their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates fromthe hotter and drier region grew and produced OTA at lower a w than other isolates. However, little genetic diver-sityin A.carbonarius wasobservedforthemicrosatellitestestedandthesamesequenceofβ-tubulingenewasob-served;thereforeintraspecificvariabilitydidnotcorrelatewiththegeographicaloriginoftheisolatesorwiththeirabilitytoproduceOTA.Climaticchangepredictionpointstodrierandhotterclimaticscenarioswhere A.tubingensisand A. niger couldbeevenmoreprevalentoverA. carbonarius, since theyare betteradaptedto extremehigh tem-perature and drier conditions.© 2013 Elsevier B.V. All rights reserved.

  • characterization and disruption of the cipc gene in the ochratoxigenic fungus Aspergillus carbonarius
    Food Research International, 2013
    Co-Authors: A Cresposempere, P V Martinezculebras, Cristina Selmalazaro, Luis Gonzalezcandelas
    Abstract:

    Abstract Aspergillus carbonarius is considered the most important ochratoxin A (OTA) producing fungi among those causing OTA contamination in grapes and grape-derived products. CipC is a small protein with unknown function that was previously found to be highly up-regulated in an OTA producer strain of A. carbonarius in comparison to a non OTA producer strain. In this study, cipC was characterized and disrupted via Agrobacterium tumefaciens-mediated transformation in an ochratoxigenic A. carbonarius strain in order to study whether this gene has a role in OTA production. Sequence analysis indicated that the promoter region of cipC contains putative binding sites for transcription factors that regulate the utilization of nutrients, the stress response and detoxification processes, all factors that can influence mycotoxin biosynthesis. Although the ∆cipC mutant grew similarly to the wild type strain, the null mutant showed a much higher OTA production. Moreover, when A. carbonarius was grown under the oxidative stress conditions imposed by the presence of hydrogen peroxide, cipC gene expression was up-regulated. These results indicate that cipC is not directly involved in OTA biosynthesis, but sequence analysis of the A. carbonarius cipC gene promoter and the phenotype of the ΔcipC disrupted mutant suggests that CipC could be a stress response protein that would be up-regulated concomitantly with OTA production.

  • proteome analysis of the fungus Aspergillus carbonarius under ochratoxin a producing conditions
    International Journal of Food Microbiology, 2011
    Co-Authors: A Cresposempere, P V Martinezculebras
    Abstract:

    Aspergillus carbonarius is an important ochratoxin A producing fungus that is responsible for mycotoxin contamination of grapes and wine. In this study, the proteomes of highly (W04-40) and weakly (W04-46) OTA-producing A. carbonarius strains were compared to identify proteins that may be involved in OTA biosynthesis. Protein samples were extracted from two biological replicates and subjected to two dimensional gel electrophoresis analysis and mass spectrometry. Expression profile comparison (PDQuest software), revealed 21 differential spots that were statistically significant and showed a two-fold change in expression, or greater. Among these, nine protein spots were identified by MALDI-MS/MS and MASCOT database and twelve remain unidentified. Of the identified proteins, seven showed a higher expression in strain W04-40 (high OTA producer) and two in strain W04-46 (low OTA producer). Some of the identified amino acid sequences shared homology with proteins involved in regulation, amino acid metabolism, oxidative stress and sporulation. It is worth noting the presence of a protein with 126.5 fold higher abundance in strain W04-40 showing homology with protein CipC, a protein with unknown function related with pathogenesis and mycotoxin production by some authors. Variations in protein expression were also further investigated at the mRNA level by real-time PCR analysis. The mRNA expression levels from three identified proteins including CipC showed correlation with protein expression levels. This study represents the first proteomic analysis for a comparison of two A. carbonarius strains with different OTA production and will contribute to a better understanding of the molecular events involved in OTA biosynthesis.

  • genes differentially expressed by Aspergillus carbonarius strains under ochratoxin a producing conditions
    International Journal of Food Microbiology, 2010
    Co-Authors: A Cresposempere, Luis Gonzalezcandelas, P V Martinezculebras
    Abstract:

    Abstract Aspergillus carbonarius is an important ochratoxin A (OTA)-producing fungus that is responsible for toxin contamination of grapes and wine, coffee and cocoa. A suppression subtractive hybridization (SSH) approach was performed with two strains of A. carbonarius, antagonistic in their OTA-production ability, to identify genes whose expression is linked with the ability to produce OTA. BlastX analysis identified 109 differentially-expressed sequences putatively involved in the production of OTA, with significant similarities (Evalue

Sonia Marin - One of the best experts on this subject based on the ideXlab platform.

  • ecophysiological characterization of Aspergillus carbonarius Aspergillus tubingensis and Aspergillus niger isolated from grapes in spanish vineyards
    International Journal of Food Microbiology, 2014
    Co-Authors: Esther Garciacela, A Cresposempere, V Sanchis, Antonio J Ramos, Sonia Marin
    Abstract:

    abstract Article history:Received 10 September 2013Received in revised form 25 November 2013Accepted 12 December 2013Available online 21 December 2013Keywords:Climate conditionsProbabilistic modelsMicrosatellitesOchratoxin ABlack aspergilli The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from differentagroclimatic regions of Spain. Growth characterization( interms of temperature and water activity requirements)of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium.A.tubingensis andA.niger showedhighermaximumtemperaturesforgrowth( N45 °Cversus40–42 °C),andlowerminimuma w requirements(0.83 a w versus 0.87 a w )thanA.carbonarius.Nodifferencesingrowthboundariesdueto their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates fromthe hotter and drier region grew and produced OTA at lower a w than other isolates. However, little genetic diver-sityin A.carbonarius wasobservedforthemicrosatellitestestedandthesamesequenceofβ-tubulingenewasob-served;thereforeintraspecificvariabilitydidnotcorrelatewiththegeographicaloriginoftheisolatesorwiththeirabilitytoproduceOTA.Climaticchangepredictionpointstodrierandhotterclimaticscenarioswhere A.tubingensisand A. niger couldbeevenmoreprevalentoverA. carbonarius, since theyare betteradaptedto extremehigh tem-perature and drier conditions.© 2013 Elsevier B.V. All rights reserved.

  • alternating temperatures and photoperiod effects on fungal growth and ochratoxin a production by Aspergillus carbonarius isolated from tunisian grapes
    International Journal of Food Microbiology, 2010
    Co-Authors: Souheib Oueslati, Salma Lasram, A J Ramos, V Sanchis, Sonia Marin, Ahmed Mliki, Abdelwahed Ghorbel
    Abstract:

    Abstract The effect of three alternating temperatures cycles (20/30, 20/37 and 25/42 °C) and photoperiod on growth and Ochratoxin A (OTA) production of six isolates of Aspergillus carbonarius on synthetic nutrient medium were investigated. The different temperature regimes affected significantly both the mycelial growth and the OTA production. The best growth and OTA production were recorded at 20/30 °C. The isolates from the region of Baddar produced the highest OTA yields. A 24 h light cycle generally enhanced the growth of A. carbonarius . Growth rates cycles of 11 h/13 h light/darkness and 24 h darkness were often similar for individual isolates, such conditions enhanced OTA production in two of the six isolates tested.

  • kinetics and spatial distribution of ota in Aspergillus carbonarius cultures
    Food Microbiology, 2006
    Co-Authors: Ana Valero, A J Ramos, V Sanchis, Joan Farre, Sonia Marin
    Abstract:

    Abstract The aim of this study was to characterize Ochratoxin A (OTA) production by Aspergillus carbonarius under different environmental conditions, and to elucidate the diffusion capacity of OTA throughout synthetic medium. One strain belonging to the species A. carbonarius isolated from vine dried fruit was single-point inoculated onto triplicate synthetic nutrient medium plates at two water activities (0.92 and 0.97) and two temperatures (20 and 30 °C). Daily radii were measured and OTA production was tested after 4, 7, 10, 14 and 18 days of incubation at four distances from the centre of colony (1–4 cm). OTA production was detected mainly at 0.97 a w . Earlier production was detected at 30 °C (optimum for growth), whereas maximum OTA concentrations were found at 20 °C. OTA production was detected from mycelium that was only a few days old and attained its optimum when mycelium was 4–7 days old at 0.97 a w . OTA diffusion was observed at 0.92 a w and 20 °C. Thus OTA production is discernable in young A. carbonarius mycelium and diffusion of the toxin has been shown to occur in a solid substrate.

  • impact of fungicides on Aspergillus carbonarius growth and ochratoxin a production on synthetic grape like medium and on grapes
    Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2006
    Co-Authors: N Belli, V Sanchis, Sonia Marin, A J Ramos
    Abstract:

    A study was undertaken to evaluate the impact of the application of several fungicide treatments used in Spanish vines on Aspergillus carbonarius growth and ochratoxin A production. Three trials were designed in order: (1) to screen 26 fungicides at the doses recommended by manufacturers on grape-like synthetic medium at 20 and 30°C; (2) to find out the minimum inhibitory concentration of each fungicide for A. carbonarius growth on synthetic medium; and (3) to investigate the effect of several fungicides on A. carbonarius-inoculated grapes. In synthetic medium nine fungicides significantly reduced A. carbonarius growth rate. Meanwhile, 13 fungicides completely inhibited its growth. In general, growth was faster at 30°C than at 20°C, contrary to ochratoxin A production. Fungicides that stopped fungal growth also inhibited ochratoxin A production, but not all the fungicides that reduced growth reduced the ochratoxin A synthesis. In general, fungicides that contained copper or strobilurins reduced both growt...

  • Aspergillus carbonarius growth and ochratoxin a production on a synthetic grape medium in relation to environmental factors
    Journal of Applied Microbiology, 2005
    Co-Authors: N Belli, A J Ramos, I Coronas, V Sanchis, Sonia Marin
    Abstract:

    Aims:  The effects of water activity (0·90–0·99 aw), temperature (15–37°C), and their interaction on growth and ochratoxin A (OTA) production by eight isolates of Aspergillus carbonarius were investigated on synthetic nutrient medium (SNM) with composition similar to grapes. Methods and Results:  Growth data were modelled by an multiple linear regression and response surface models were obtained. Aspergillus carbonarius grew much faster at 30°C than at the other temperature levels tested and its growth rate increased with increasing aw, maximum growth rate being between 0·95 and 0·99 aw. In general, isolates grew faster at 35–37°C than at 20°C, although no significant differences were found between these temperatures. OTA accumulation was also favoured by high aw levels, and although it was observed in the whole range of temperatures, maximum amounts were detected at 20°C. No OTA was found at the most unfavourable growth conditions. Conclusions:  Optimum aw level for growth seems to correspond with optimum for OTA production, meanwhile the most propitious temperature for the toxin production was below the best one for growth. Significance and Impact of the Study:  Prediction of A. carbonarius growth would allow estimating their presence and therefore, the OTA production, as it was found that conditions for the toxin production were more limited than those permitting growth.

Ekambaram Nakkeeran - One of the best experts on this subject based on the ideXlab platform.

  • Process Assessment for the Purification of Aspergillus carbonarius Polygalacturonase Produced by Submerged and Solid-State Fermentations
    International journal of engineering and technology, 2020
    Co-Authors: Ekambaram Nakkeeran, R Subramanian, S. Umesh Kumar
    Abstract:

    Integrated membrane process (IMP) and alginate affinity precipitation (AAP) were assessed for the purification of Aspergillus carbonarius polygalacturonase (PG) obtained after submerged (SmF) and solid-state fermentations (SSF). IMP enhanced the purity (4.69 fold) and recovery (76%) of SmF-PG, but did not improve the purity of SSF and commercial PG due to the presence of other similar molecular mass proteins. AAP enhanced the PG purity and recovery in all the PG samples (SmF, SSF and commercial PG). IMP offers several process advantages over AAP but not suitable for purification of all types of PGs. Our studies on SmF- and SSF-PG had shown that downstream process needs are specific for individual cases and warrants careful considerations.

  • Techno-economic analysis of processes for Aspergillus carbonarius polygalacturonase production
    Journal of Bioscience and Bioengineering, 2012
    Co-Authors: Ekambaram Nakkeeran, Marichetti Kuppuswamy Gowthaman, Sukumaran Umesh-kumar, Rangaswamy Subramanian
    Abstract:

    Abstract A techno-economic analysis of submerged (SmF) and solid state fermentation (SSF) processes for Aspergillus carbonarius polygalacturonase production was performed to make an appropriate process selection. The downstream processing involved integrated membrane process (IMP) and alginate affinity precipitation (AAP). For a production scale of 30 kL purified polygalacturonase concentrate per year, the total upstream cost of SmF was 14% lower than the SSF process. Downstream processing cost by IMP was 47% lower than AAP. The SmF-IMP process required a total capital investment that was 15–24% lower than the SmF-AAP and SSF-AAP processes. The corresponding unitary product cost was also lower by 24–36% in SmF-IMP process. Thus the SmF-IMP process proved to be very attractive from an economic point of view.

  • Aspergillus carbonarius polygalacturonases purified by integrated membrane process and affinity precipitation for apple juice production
    Bioresource Technology, 2011
    Co-Authors: Ekambaram Nakkeeran, Sukumaran Umeshkumar, R Subramanian
    Abstract:

    Aspergillus carbonarius, when grown by submerged and solid-state fermentation, produces different molecular forms of polygalacturonase (PG; EC 3.2.1.15), among them a 42 kDa PG with a high specific activity of 7000 U/mg protein. When the enzymes were purified by integrated membrane process (IMP) and alginate affinity precipitation (AAP), the two processes concentrated different forms of the enzyme. The AAP process selectively purified and concentrated the high active PG whereas the IMP yielded different PGs and also amylase and protease. Evaluation of the AAP enzyme preparations for apple juice preparation under conditions usually employed commercially demonstrated that the high activity PG did not result in good juice clarity. With IMP processed enzymes, juice yields and clarity were similar to that obtained with commercial PG from A. niger.

  • Effect of stirring and pump on membrane processing of Aspergillus carbonarius culture broth for polygalacturonase
    Biochemical Engineering Journal, 2010
    Co-Authors: Ekambaram Nakkeeran, Rangaswamy Subramanian
    Abstract:

    Stirring effect in a stirred membrane cell and the type of pumping action in a cross-flow filtration system were assessed from the viewpoint of recovery of polygalacturonase (PG) from Aspergillus carbonarius culture broth. PG and protein loss increased with stirring speed (shear stress) as well as processing time under simulated conditions of a stirred membrane cell. When the stirring conditions did not exceed the critical speed of 400 rpm, corresponding to a shear stress of 2.1 Pa, higher recoveries of PG (88%) and protein (96%) were obtained. Processing culture broth using a gear pump increased PG and protein loss with processing time and resulted in 71% PG and 54% protein loss after 3 h of pumping, while the loss of PG and protein was negligible when a peristaltic pump was used. The results revealed that processing shear sensitive enzymes like PG required determination of critical shear stress and selection of suitable pump to prevent losses in the membrane process.

  • extraction purification and concentration of partially saturated canthaxanthin from Aspergillus carbonarius
    Bioresource Technology, 2010
    Co-Authors: Ekambaram Nakkeeran, G. Vijayalakshmi, D Krupa, N Kumaresan, R Subramanian
    Abstract:

    Abstract A mutant Aspergillus carbonarius produces partially saturated canthaxanthin (PSC; C40H62O2) during submerged fermentation. The pigment was extracted from dried biomass using various organic solvents and purified using nanofiltration (NF) and nonporous membranes. Particle size had a great influence; PSC extractability from fines fraction of biomass (75–105 μm) was 1.5-fold higher compared to the coarse fraction (850–920 μm) in ethanol. Among the four solvents, hexane exhibited the highest PSC extractability of 5.83 mg/g and purity of 32 mg/g. On a relative scale, the extraction performance of hexane, acetone, methanol and ethanol were in the order 100, 16.1, 7.5 and 5.4. An assessment based on enrichment factor and permeate flux revealed notable performance with NF-250 membrane in ethanol extract followed by NF-200 and NF-GKSS membranes in methanol extract. These results suggested the suitability of hexane for extraction followed by alcohol phase purification and concentration employing NF. Accordingly, a PSC purity of 206 mg/g was achieved.

V Sanchis - One of the best experts on this subject based on the ideXlab platform.

  • ecophysiological characterization of Aspergillus carbonarius Aspergillus tubingensis and Aspergillus niger isolated from grapes in spanish vineyards
    International Journal of Food Microbiology, 2014
    Co-Authors: Esther Garciacela, A Cresposempere, V Sanchis, Antonio J Ramos, Sonia Marin
    Abstract:

    abstract Article history:Received 10 September 2013Received in revised form 25 November 2013Accepted 12 December 2013Available online 21 December 2013Keywords:Climate conditionsProbabilistic modelsMicrosatellitesOchratoxin ABlack aspergilli The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from differentagroclimatic regions of Spain. Growth characterization( interms of temperature and water activity requirements)of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium.A.tubingensis andA.niger showedhighermaximumtemperaturesforgrowth( N45 °Cversus40–42 °C),andlowerminimuma w requirements(0.83 a w versus 0.87 a w )thanA.carbonarius.Nodifferencesingrowthboundariesdueto their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates fromthe hotter and drier region grew and produced OTA at lower a w than other isolates. However, little genetic diver-sityin A.carbonarius wasobservedforthemicrosatellitestestedandthesamesequenceofβ-tubulingenewasob-served;thereforeintraspecificvariabilitydidnotcorrelatewiththegeographicaloriginoftheisolatesorwiththeirabilitytoproduceOTA.Climaticchangepredictionpointstodrierandhotterclimaticscenarioswhere A.tubingensisand A. niger couldbeevenmoreprevalentoverA. carbonarius, since theyare betteradaptedto extremehigh tem-perature and drier conditions.© 2013 Elsevier B.V. All rights reserved.

  • alternating temperatures and photoperiod effects on fungal growth and ochratoxin a production by Aspergillus carbonarius isolated from tunisian grapes
    International Journal of Food Microbiology, 2010
    Co-Authors: Souheib Oueslati, Salma Lasram, A J Ramos, V Sanchis, Sonia Marin, Ahmed Mliki, Abdelwahed Ghorbel
    Abstract:

    Abstract The effect of three alternating temperatures cycles (20/30, 20/37 and 25/42 °C) and photoperiod on growth and Ochratoxin A (OTA) production of six isolates of Aspergillus carbonarius on synthetic nutrient medium were investigated. The different temperature regimes affected significantly both the mycelial growth and the OTA production. The best growth and OTA production were recorded at 20/30 °C. The isolates from the region of Baddar produced the highest OTA yields. A 24 h light cycle generally enhanced the growth of A. carbonarius . Growth rates cycles of 11 h/13 h light/darkness and 24 h darkness were often similar for individual isolates, such conditions enhanced OTA production in two of the six isolates tested.

  • kinetics and spatial distribution of ota in Aspergillus carbonarius cultures
    Food Microbiology, 2006
    Co-Authors: Ana Valero, A J Ramos, V Sanchis, Joan Farre, Sonia Marin
    Abstract:

    Abstract The aim of this study was to characterize Ochratoxin A (OTA) production by Aspergillus carbonarius under different environmental conditions, and to elucidate the diffusion capacity of OTA throughout synthetic medium. One strain belonging to the species A. carbonarius isolated from vine dried fruit was single-point inoculated onto triplicate synthetic nutrient medium plates at two water activities (0.92 and 0.97) and two temperatures (20 and 30 °C). Daily radii were measured and OTA production was tested after 4, 7, 10, 14 and 18 days of incubation at four distances from the centre of colony (1–4 cm). OTA production was detected mainly at 0.97 a w . Earlier production was detected at 30 °C (optimum for growth), whereas maximum OTA concentrations were found at 20 °C. OTA production was detected from mycelium that was only a few days old and attained its optimum when mycelium was 4–7 days old at 0.97 a w . OTA diffusion was observed at 0.92 a w and 20 °C. Thus OTA production is discernable in young A. carbonarius mycelium and diffusion of the toxin has been shown to occur in a solid substrate.

  • impact of fungicides on Aspergillus carbonarius growth and ochratoxin a production on synthetic grape like medium and on grapes
    Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2006
    Co-Authors: N Belli, V Sanchis, Sonia Marin, A J Ramos
    Abstract:

    A study was undertaken to evaluate the impact of the application of several fungicide treatments used in Spanish vines on Aspergillus carbonarius growth and ochratoxin A production. Three trials were designed in order: (1) to screen 26 fungicides at the doses recommended by manufacturers on grape-like synthetic medium at 20 and 30°C; (2) to find out the minimum inhibitory concentration of each fungicide for A. carbonarius growth on synthetic medium; and (3) to investigate the effect of several fungicides on A. carbonarius-inoculated grapes. In synthetic medium nine fungicides significantly reduced A. carbonarius growth rate. Meanwhile, 13 fungicides completely inhibited its growth. In general, growth was faster at 30°C than at 20°C, contrary to ochratoxin A production. Fungicides that stopped fungal growth also inhibited ochratoxin A production, but not all the fungicides that reduced growth reduced the ochratoxin A synthesis. In general, fungicides that contained copper or strobilurins reduced both growt...

  • Aspergillus carbonarius growth and ochratoxin a production on a synthetic grape medium in relation to environmental factors
    Journal of Applied Microbiology, 2005
    Co-Authors: N Belli, A J Ramos, I Coronas, V Sanchis, Sonia Marin
    Abstract:

    Aims:  The effects of water activity (0·90–0·99 aw), temperature (15–37°C), and their interaction on growth and ochratoxin A (OTA) production by eight isolates of Aspergillus carbonarius were investigated on synthetic nutrient medium (SNM) with composition similar to grapes. Methods and Results:  Growth data were modelled by an multiple linear regression and response surface models were obtained. Aspergillus carbonarius grew much faster at 30°C than at the other temperature levels tested and its growth rate increased with increasing aw, maximum growth rate being between 0·95 and 0·99 aw. In general, isolates grew faster at 35–37°C than at 20°C, although no significant differences were found between these temperatures. OTA accumulation was also favoured by high aw levels, and although it was observed in the whole range of temperatures, maximum amounts were detected at 20°C. No OTA was found at the most unfavourable growth conditions. Conclusions:  Optimum aw level for growth seems to correspond with optimum for OTA production, meanwhile the most propitious temperature for the toxin production was below the best one for growth. Significance and Impact of the Study:  Prediction of A. carbonarius growth would allow estimating their presence and therefore, the OTA production, as it was found that conditions for the toxin production were more limited than those permitting growth.