Showing papers on "Aspergillus niger published in 2009"
TL;DR: Compounds such as malformins, naptho-γ-pyrones, and bicoumarins (kotanins) call for monitoring in food, feed, and biotechnology products as well as for a better toxicological evaluation, since they are often produced in large amounts by the black aspergilli.
Abstract: Filamentous fungi in the Aspergillus section Nigri (the black aspergilli) represent some of the most widespread food and feed contaminants known but they are also some of the most important workhorses used by the biotechnological industry. The Nigri section consists of six commonly found species (excluding A. aculeatus and its close relatives) from which currently 145 different secondary metabolites have been isolated and/or detected. From a human and animal safety point of view, the mycotoxins ochratoxin A (from A. carbonarius and less frequently A. niger) and fumonisin B2 (from A. niger) are currently the most problematic compounds. Especially in foods and feeds such as coffee, nuts, dried fruits, and grape-based products where fumonisin-producing fusaria are not a problem, fumonisins pose a risk. Moreover, compounds such as malformins, naptho-γ-pyrones, and bicoumarins (kotanins) call for monitoring in food, feed, and biotechnology products as well as for a better toxicological evaluation, since they are often produced in large amounts by the black aspergilli. For chemical differentiation/identification of the less toxic species the diketopiperazine asperazine can be used as a positive marker since it is consistently produced by A. tubingensis (177 of 177 strains tested) and A. acidus (47 of 47 strains tested) but never by A. niger (140 strains tested). Naptho-γ-pyrones are the compounds produced in the highest quantities and are produced by all six common species in the group (A. niger 134 of 140; A. tubingensis 169 of 177; A. acidus 44 of 47; A. carbonarius 40 of 40, A. brasiliensis 18 of 18; and A. ibericus three of three).
292 citations
TL;DR: The microbiology, toxigenicity and epidemiology of A. flavus are reviewed as well as the clinical characteristics, diagnosis and management of infections caused by this organism are described.
Abstract: Invasive aspergillosis is rare in immunocompetent people but contributes to significant morbidity and mortality in immunosuppressed patients. The majority (approximately 80%) of invasive Aspergillus infections is caused by Aspergillus fumigatus. The second most frequent (approximately 15-20%) pathogenic species is Aspergillus flavus and to a lesser extent, Aspergillus niger and Aspergillus terreus. Aspergillus flavus has emerged as a predominant pathogen in patients with fungal sinusitis and fungal keratitis in several institutions worldwide. To date, there has not been any publication exclusively reviewing the topic of A. flavus in the literature. This article reviews the microbiology, toxigenicity and epidemiology of A. flavus as well as describes the clinical characteristics, diagnosis and management of infections caused by this organism.
232 citations
TL;DR: Kinetics of cellulase production from an indigenous strain of Aspergillus niger MS82 is reported and it was observed that the production of endoglucanase reaches its maximum during exponential phase of growth, while b-glucosidase during the Stationary phase.
193 citations
TL;DR: A new fungal metabolite, nygerone A (), featuring a unique 1-phenylpyridin-4(1H)-one core that had previously not been reported from any natural source, has been obtained from Aspergillus niger using a chemical epigenetics methodology.
Abstract: A new fungal metabolite, nygerone A (), featuring a unique 1-phenylpyridin-4(1H)-one core that had previously not been reported from any natural source, has been obtained from Aspergillus niger using a chemical epigenetics methodology.
176 citations
TL;DR: Results of sequential extraction showed that organic acids produced by Aspergillus niger were effective in removing the exchangeable, carbonate, and Fe/Mn oxide fractions of Cu, Cd, Pb and Zn; and after both processes the metals remaining in the soil were mainly bound in stable fractions.
166 citations
TL;DR: It is suggested that UVC irradiation can effectively inactivate spores of A. niger but the efficacy of UVC radiation against fungal spores varies significantly according to methods of exposure to the irradiation, and among genera.
151 citations
TL;DR: Differences at genome content, substrate specificity of the enzymes and gene regulation in these three Aspergilli likely reflect their individual adaptation to their natural biotope.
146 citations
TL;DR: In this present study forty nine different plants used in traditional Indian medicine were examined against Aspergillus niger using agar well diffusion method and methanolic extracts of 43 plants exhibited varying degrees of inhibition activity against the fungi.
Abstract: In this present study forty nine different plants used in traditional Indian medicine were examined against Aspergillus niger using agar well diffusion method. The methanolic extracts of 43 plants exhibited varying degrees of inhibition activity against the fungi. Among the forty nine plants studied 86% of the plants had antifungal activity while the remaining 14% had no antifungal activity. The extract from Grewia arborea showed maximum activity. Emblica officinales, Heldigordia populipolia, Hyptis sueolences, Moringa heterophylla, Strychnos nuxvomica and Vitex negundo did not exhibit antifungal activity at the condition studied. Keywords: Aspergillus niger, Antifungal, medicinal plants
133 citations
TL;DR: An extracellular lipase from Aspergillus niger NCIM 1207 has been purified to homogeneity using ammonium sulfate precipitation followed by phenyl sepharose and Sephacryl-100 gel chromatography and appears to be unique since it cleaved triolein at only 3-position releasing 1,2-diolein.
128 citations
TL;DR: Indian borage oil (IBO) has the potential for use as a botanical fungitoxicant against fungal attack in stored food commodities.
117 citations
TL;DR: Aims: To characterize and identify a new taxol‐producing fungal strain HD86‐9 isolated from Taxus cuspidata in China.
Abstract: Aims: To characterize and identify a new taxol-producing fungal strain HD86-9 isolated from Taxus cuspidata in China.
Methods and Results: Taxol extracted from strain HD86-9 was identified by HPLC and MS analyses. Strain HD86-9 was cultured and its morphology and phenotypes were described. HD86-9 displayed morphology most similar to that of Aspergillus niger but presented differences in the shape and size of the conidia. The growth evaluation showed that the maximal tolerable temperature of the new strain was 43°C, higher than that of the model Aspergillus niger. The 18S rDNA and the internal transcribed spacer region including the 5·8S rDNA of HD86-9 were amplified by PCR; molecular analysis of these sequences revealed their high similarity of 98% to those of Aspergillus niger.
Conclusions: The morphology and molecular analysis identified HD86-9 as a new variant of taxol-producing endophytic fungi, and it was named Aspergillus niger var. taxi D.P. Zhou, K. Zhao and W.X. Ping, var. nov.
Significance and Impact of the Study: As the first report of a taxol-producing variant of Aspergillus niger species, this study offers important information and a new resource for the production of an important anticancer drug by endofungus fermentation.
TL;DR: The saprobic fungus Aspergillus niger is an efficient producer of a suite of extracellular enzymes involved in carbohydrate modification and degradation and the prediction of at least 39 genes involved in the depolymerisation of the backbone of pectin is predicted.
TL;DR: A hybrid of an enzyme-based microbial fuel cell was developed and demonstrated its activity both biochemically and electrochemically and observed much higher activity over yeast cells not displaying glucose oxidase as well as over purified glucose oxidation from Aspergillus niger.
Abstract: A novel concept for a biofuel cell is presented. Enzyme based fuel cells suffer from enzyme instability when a long time of operation is required. Hence, a system that will continuously produce the biocatalyst needed for the system is necessary. A hybrid of an enzyme-based microbial fuel cell was developed. The redox enzyme glucose oxidase from Aspergillus niger was displayed on the surface of Saccharomyces cereviciae using the Yeast Surface Display System in a high copy number and as an active enzyme. We have demonstrated its activity both biochemically and electrochemically and observed much higher activity over yeast cells not displaying glucose oxidase as well as over purified glucose oxidase from Aspergillus niger. Further, we were able to construct a biofuel cell, where the anode was comprised of the yeast cells displaying glucose oxidase in the presence of a mediator (methylene blue) and the cathode compartment was comprised of the oxygen reducing enzyme laccase from Trametes versicolor and a redox...
TL;DR: Different characterization studies showed that the extracellular enzyme secreted by Aspergillus niger NCIM 616 might be responsible for both formation and capping of the metal nanoparticles.
Abstract: The development of an eco-friendly and reliable process for the synthesis of gold nanomaterials using microorganisms is gaining importance in the field of nanotechnology. In the present study, gold nanoparticles have been synthesized by reduction of aqueous gold ions using the culture supernatant of Aspergillus niger NCIM 616. The synthesis of the gold nanoparticles was monitored by UV-visible spectroscopy. The particles thereby obtained were characterized by UV, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The stability of the synthesized gold nanoparticles was analyzed by zeta potential measurement. Treatment of the fungal supernatant with aqueous Au+ ions produced nanoparticles with an average particle size of 12.79 ± 5.61 nm. Different characterization studies showed that the extracellular enzyme secreted by Aspergillus niger NCIM 616 might be responsible for both formation and capping of the metal nanoparticles.
TL;DR: The 11,200 gene models predicted in the genome of A. niger strain ATCC 1015 were the data source for the analysis and secreted proteins identified by mass spectrometry were used to guide the correction of about 20 gene models.
18 Sep 2009-Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment
TL;DR: Findings suggest that there is a potential risk of exposure to FB2 in the grape–wine chain for consumers and that A. niger may represent the major fumonisin-producing species among black Aspergilli occurring on grapes.
Abstract: Aspergillus niger has been recently found to produce fumonisin B2 (FB2). Thirty-one strains belonging to four Aspergillus species isolated from grape were evaluated for FB2 production on agar plates. Four out of eight strains of A. niger produced FB2 (29–293 µg g−1). None of the strains of A. uvarum (n = 7), A. tubingensis (8) and A. carbonarius (8) produced detectable amounts of toxin. The capability to produce FB2 was also confirmed by some A. niger strains artificially inoculated on grape berries. Natural occurrence of FB2, at levels of 0.01 and 0.4 µg ml−1, was found in two samples of must collected in Apulian cellars in 2007. This is the first report of FB2 contamination in must. These findings suggest that there is a potential risk of exposure to FB2 in the grape–wine chain for consumers and that A. niger may represent the major fumonisin-producing species among black Aspergilli occurring on grapes.
TL;DR: The results indicated that the use of xylanases could help to reduce the amount of chlorine compounds used in cellulose pulp treatment.
Abstract: This study describes the production of xylanases from Aspergillus niveus, A. niger, and A. ochraceus under solid-state fermentation using agro-industrial residues as substrates. Enzyme production was improved using a mixture of wheat bran and yeast extract or peptone. When a mixture of corncob and wheat bran was used, xylanase production from A. niger and A. ochraceus increased by 18%. All cultures were incubated at 30 °C at 70–80% relative humidity for 96 h. For biobleaching assays, 10 or 35 U of xylanase/g dry cellulose pulp were incubated at pH 5.5 for 1 or 2 h, at 55 °C. The delignification efficiency was 20%, the brightness (percentage of ISO) increased two to three points and the viscosity was maintained confirming the absence of cellulolytic activity. These results indicated that the use of xylanases could help to reduce the amount of chlorine compounds used in cellulose pulp treatment.
TL;DR: The synthesis of inulinase and invertase from A. niger SL-09 was enhanced significantly by the inoculation of Lactobacillus sp.
TL;DR: The abundance of annotated stress sensing histidine kinases and transcriptional regulators in each Aspergillus species indicates that the applicability of yeast-based models to fully describe and explain the stress-responses of these fungi is limited.
TL;DR: The antifungal activity of compounds was better than their antibacterial activity and the synthetic route involves the reaction of equimolar quantities of isomeric fluorobenzoyl chlorides with potassium thiocyanate in anhydrous acetone to afford the corresponding isothiocyantes in situ.
TL;DR: The tannase from A. niger GH1 was significantly inhibited by PMSF (phenylmethylsulfonyl fluoride), and therefore, it is possible to consider the presence of a serine or cysteine residue in the catalytic site.
Abstract: Aspergillus niger GH1 previously isolated and identified by our group as a wild tannase producer was grown under solid-state (SSC) and submerged culture (SmC) conditions to select the enzyme production system. For tannase purification, extracellular tannase was produced under SSC using polyurethane foam as the inert support. Tannase was purified to apparent homogeneity by ultrafiltration, anion-exchange chromatography, and gel filtration that led to a purified enzyme with a specific activity of 238.14 IU/mg protein with a final yield of 0.3% and a purification fold of 46. Three bands were found on the SDS-PAG with molecular masses of 50, 75, and 100 kDa. PI of 3.5 and 7.1% Nglycosylation were noted. Temperature and pH optima were 60 degrees and 6.0 [methyl 3,4,5-trihydroxybenzoate (MTB) as substrate], respectively. Tannase was found with a KM value of 0.41 x 10-4 M and the value of Vmax was 11.03 micromoL/min at 60 degrees for MTB. Effects of several metal salts, solvents, surfactants, and typical enzyme inhibitors on tannase activity were evaluated to establish the novelty of the enzyme. Finally, the tannase from A. niger GH1 was significantly inhibited by PMSF (phenylmethylsulfonyl fluoride), and therefore, it is possible to consider the presence of a serine or cysteine residue in the catalytic site.
TL;DR: This study demonstrates that “tuning” enzyme glycosylation for expression from heterologous expression hosts is essential for generating engineered enzymes with optimal stability and activity.
Abstract: The filamentous fungi Trichoderma reesei and Penicillium funiculosum produce highly effective enzyme mixtures that degrade the cellulose and hemicellulose components of plant cell walls. Many fungal species produce a glycoside hydrolase family 7 (Cel7A) cellobiohydrolase, a class of enzymes that catalytically process from the reducing end of cellulose. A direct amino acid comparison of these two enzymes shows that they not only have high amino acid homology, but also contain analogous N-linked glycosylation sites on the catalytic domain. We have previously shown (Jeoh et al. in Biotechnol Biofuels, 1:10, 2008) that expression of T. reesei cellobiohydrolase I in a commonly used industrial expression host, Aspergillus niger var. awamori, results in an increase in the amount of N-linked glycosylation of the enzyme, which negatively affects crystalline cellulose degradation activity as well as thermal stability. This complementary study examines the significance of individual N-linked glycans on the surface of the catalytic domain of Cel7A cellobiohydrolases from T. reesei and P. funiculosum by genetically adding or removing N-linked glycosylation motifs using site directed mutagenesis. Modified enzymes, expressed in A. niger var. awamori, were tested for activity and thermal stability. It was concluded that N-linked glycans in peptide loops that form part of the active site tunnel have the greatest impact on both thermal stability and enzymatic activity on crystalline cellulose for both the T. reesei and P. funiculosum Cel7A enzymes. Specifically, for the Cel7A T. reesei enzyme expressed in A. niger var. awamori, removal of the N384 glycosylation site yields a mutant with 70% greater activity after 120 h compared to the heterologously expressed wild type T. reesei enzyme. In addition, similar activity improvements were found to be associated with the addition of a new glycosylation motif at N194 in P. funiculosum. This mutant also exhibits 70% greater activity after 120 h compared to the wild type P. funiculosum enzyme expressed in A. niger var. awamori. Overall, this study demonstrates that “tuning” enzyme glycosylation for expression from heterologous expression hosts is essential for generating engineered enzymes with optimal stability and activity.
TL;DR: The present study shows that the regulation of fumonisin production is very different in Aspergillus niger and Fusarium, and that food and feeds preserved by addition of sugar or salts may be good substrates for fumoniain B2 production by A. niger.
Abstract: Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual fumonisin B2 (FB2) production in four strains of this biotechnologically important workhorse. In the present study, a screening of 5 A. niger strains and 25 assumed fumonisin producing Fusarium strains from 6 species, showed that all 5 A. niger strains produced FB2 and 23 of 25 Fusarium produced fumonisin B1 and other isoforms (fumonisin B2 and B3). Five A. niger and five Fusarium spp. were incubated at six different temperatures from 15-42°C on Czapek Yeast Agar +5% salt or Potato Dextrose Agar. A. niger had the highest production of FB2 at 25-30°C whereas Fusarium spp. had the maximal production of FB1 and FB2 at 20-25°C. Addition of 2.5-5% NaCl, or 10-20% sucrose increased the FB2 production of A. niger, whereas addition of glycerol reduced FB2 production. All three water activity lowering solutes reduced the fumonisin production of the Fusarium species. The present study shows that the regulation of fumonisin production is very different in A. niger and Fusarium, and that food and feeds preserved by addition of sugar or salts may be good substrates for fumonisin B2 production by A. niger.
TL;DR: An integrated genomics approach was developed to determine cellular responses of A. niger to protein production in well-controlled fermentations and reduction of protein degradation through the removal of the ERAD factor doaA combined with overexpression of the oligosaccharyl transferase sttC resulted in a small increase in GUS expression.
TL;DR: In this paper, Aspergillus niger isolated from pistachio shell was applied to remove iron impurities from an Iranian kaolin sample, and three models were suggested to predict response values based on the mentioned variables.
TL;DR: A novel series of 1, 2,3 triazole compounds possessing 1,2,4 oxadiazole ring were efficiently synthesized and evaluated for their in vitro antifungal activities using standard cup plate method.
TL;DR: 3-(3,4,5-trimethoxybenzylideneamino)-6,8-dibromo-2-phenylquinazolin-4(3H)-one 10 was found to be the most potent anti-microbial activity and found to exhibit more anti-fungal than anti-bacterial activity.
TL;DR: The results of this study show that all the fungi produced one toxin or the other as detected in the culture filtrates of isolated fungi, however, only three of these toxins were identified namely aflatoxin B2, fumonisin B1, and zearalenone.
Abstract: A study was conducted to determine the fungi associated with maize (Zea mays), rice (Oryza sativa) and millet (Pennisetum typhoiodes) in storage. Mycotoxin production by isolated fungi was subsequently evaluated using the thin layer chromatography technique. Eight different fungi were isolated altogether namely Aspergillus terreus, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Penicillium italicum, Penicillium spinulosum, Rhizopus stolonifer and Fusarium sp. The results of this study show that all the fungi produced one toxin or the other as detected in the culture filtrates of isolated fungi. However, only three of these toxins were identified namely aflatoxin B1, fumonisin B1, and zearalenone. The retention factors (Rf) of all the toxins produced were determined.
TL;DR: Transformer strains of H. polymorpha capable of growth and alcoholic fermentation on a minimal medium supplemented with birchwood xylan as a sole carbon source at 48 degrees C were found.
Journal Article•
TL;DR: The isolated strain has broad spectrum of antagonistic activity against Gram positive and Gram negative bacteria and Aspergillus sp.
Abstract: The aim of the present study was to isolate and to indentify the actinomycetes having antagonistic activity. An actinomycetes strain isolated from marine sediment samples collected at the Puducherry coast of India, showed antibacterial activity against selected microbial pathogens. The nutritional requirements and cultural conditions for maximal growth and yield of secondary metabolites have been optimized under shakeflask conditions. The growth and yield of secondary metabolites was maximal with the use of ISP 1 medium supplemented with sea water, pH 7.4, and incubation temperature of 28℃, salt tolerance of 2% and incubation time of 4-7 days. Based on morphological, biochemical, physiological and phylogenetic characterization, the strain was identified as Nocardiopsis sp. VITSVK5 (FJ973467). The petroleum ether extract (1000μg/ml) obtained from the isolate showed significant antibacterial activity against Gram negative bacteria- Escherichia coli (20 mm), Pseudomonas aeruginosa (18 mm) and Klebsiella pneumonia (15 mm) and Gram positive bacteria- Enterococcus faecalis (20 mm), Bacillus cereus (13 mm) and Staphylococcus aureus (6 mm) when compared with streptomycin (25μg/disc). The ethyl acetate extract (1000μg/ml) showed antifungal activity against Aspergillus fumigatus (23 mm), Aspergillus flavus (15 mm) and Aspergillus niger (12 mm) when compared with amphotericin-B (25μg/disc). The chloroform extract (1000μg/ml) was very effective against yeasts, Candida cruzi (18 mm), Candida tropicans (15 mm) and Candida albicans (14 mm) when compared to streptomycin (25μg/disc). In conclusion the isolated strain has broad spectrum of antagonistic activity against Gram positive and Gram negative bacteria and Aspergillus sp.