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Sample records for aspergillus niger isolated

  1. Glucoamylase production by a newly isolated strain of Aspergillus niger

    SciTech Connect

    Sinkar, V.P.; Lewis, N.F.

    1982-01-01

    Glucoamylase production by Aspergillus niger 57 was studied in complex and synthetic media under stationary vs. submerged conditions. Stationary cultivation resulted in significantly greater yields than did submerged culture. Crude enzyme activity was optimum at 60 degrees and pH 4.0.

  2. Naphtho-gamma-pyrone production by Aspergillus niger isolated from stored cottonseed.

    PubMed Central

    Ehrlich, K C; DeLucca, A J; Ciegler, A

    1984-01-01

    Aspergillus niger was found to be the predominant fungal contaminant of stored cottonseed. Seven strains were isolated and grown on rice. The hexane-insoluble material from methylene chloride extracts of 2-week-old cultures contained components toxic to mice. Based on high-pressure thin-layer and liquid chromatographic analyses, the major components in the mixture were eight different naphtho-gamma-pyrones. Of these, the hydrated dimeric naphthopyrones aurasperones B and C occurred in higher yield than aurasperones A, iso-A, and D and the monomeric naphthopyrones flavasperone and rubrofusarin, all of which were present in the mixture. In addition, fonsecin monomethyl ether was isolated. This metabolite may be a precursor in the biosynthesis of the hydrated aurasperones; it has not been identified previously as a metabolite of A. niger. The relative amounts of the different naphthopyrones were dependent on both the growth substrate and the fungal isolate. Images PMID:6548104

  3. Production of catalases by Aspergillus niger isolates as a response to pollutant stress by heavy metals

    SciTech Connect

    Buckova, M.; Godocikova, J.; Simonovicova, A.; Polek, B.

    2005-04-15

    Isolates of Aspergillus niger, selected from the coal dust of a mine containing arsenic (As; 400 mg/kg) and from the river sediment of mine surroundings (As, 1651 mg/kg, Sb, 362 mg/kg), growing in minimal nitrate medium in the phase of hyphal development and spore formation, exhibited much higher levels of total catalase activity than the same species from the culture collection or a culture adapted to soil contaminated with As (5 mg/L). Electrophoretic resolution of catalases in cell-free extracts revealed three isozymes of catalases and production of individual isozymes was not significantly affected by stress environments. Exogenously added stressors (As{sup 5+}, Cd{sup 2+}, Cu{sup 2+}) at final concentrations of 25 and 50 mg/L and H{sub 2}O{sub 2} (20 or 40 m(M)) mostly stimulated production of catalases only in isolates from mines surroundings, and H{sub 2}O{sub 2} and Hg{sup 2+} caused the disappearance of the smallest catalase I. Isolates exhibited a higher tolerance of the toxic effects of heavy metals and H{sub 2}O{sub 2}, as monitored by growth, than did the strain from the culture collection.

  4. Isolation of a thermostable acid phytase from Aspergillus niger UFV-1 with strong proteolysis resistance

    PubMed Central

    Monteiro, Paulo S.; Guimares, Valria M.; de Melo, Ricardo R.; de Rezende, Sebastio T.

    2015-01-01

    An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), indicating that it may be a dimer. It presented an optimum temperature of 60 C and optimum pH of 2.0. The K M for sodium phytate hydrolysis was 30.9 mM, while the k cat and k cat / K M were 1.46 10 5 s ?1 and 4.7 10 6 s ?1 .M ?1 , respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg 2+ , Cd 2+ , K + and Ca 2+ , and it was drastically inhibited by F ? . The enzyme displayed high thermostability, retaining more than 90% activity at 60 C during 120 h and displayed a t 1/2 of 94.5 h and 6.2 h at 70 C and 80 C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 ?mol phosphate/mL after 2.5 h of treatment. PMID:26221114

  5. Isolation, properties, and crystallization of an iron-chlorin protein from Aspergillus niger.

    PubMed

    Horie, S; Watanabe, T; Nakamura, S

    1976-09-01

    A green iron-chlorin protein was purified 160-fold from a lyophilized extract of Aspergillus niger by ion-exchange chromatography and gel filtration with a yield of 25%. The purified preparation appeared nearly homogeneous on sedimentation analysis and the sedimentation coefficient of the protein at infinite dilution was 13.4S. Its molecular weight was calculated to be 2.8--3.2 X 10(5) from sedimentation and gel filtration data. The ferric form of the protein had absorption maxima at 587.5 and 708 nm in the visible region and a Soret band at 404 nm. High-spin ESR signals of a rhombically distorted ferric iron-chlorin complex were observed at g = 6.5 and 5.3 together with unidentified, weaker signals at g = 4.3 and 2.0. The ferric form reacted readily with cyanide to give a complex showing absorption peaks at 422 and 632 nm and a shoulder at about 595 nm. When the protein combined with cyanide its high-spin ESR signals disappeared and low-spin signals at g = 1.88, 2.29, anous form having absorption maxima at 622 and about 410 nm. The rate of reduction by dithionite was slightly reduced by the presence of either nitrite or sulfite, and greatly accelerated by the presence of hydroxylamine. The reduced spectrum obtained in the presence of hydroxylamine had maxima at 620 and about 420 nm. The ferric cyanide complex did not show any spectral change on addition of dithionite. The green prosthetic group could be extracted with acidified acetone and the absorption maxima of the pyridine ferrihemochrome were at 413 and 599 nm. On removal of metal from the prosthetic group the characteristic spectrum of a chlorin was obtained. The absorption maxima of a solution of the chlorin in benzene were at 403, 501, 537, 576, 595, and 655 nm, the 655 nm band being strongest of those in the visible region. No significant amount of flavin was detected in the purified preparation. The iron-chlorin protein catalyzed methyl viologen-linked reduction of hydroxylamine and also that of nitrite at a slower rate under the same conditions, but not evidence that it reduced sulfite was obtained in the present study. The purified preparation also had high catalase [ec 1.11.1.6] activity. Crystalline material was obtained by gradual concentration of the purified preparation at about pH 6. PMID:977555

  6. Biotransformation of Stypotriol triacetate by Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Areche, Carlos; Vaca, Inmaculada; Labbe, Pamela; Soto-Delgado, Jorge; Astudillo, Luis; Silva, Mario; Rovirosa, Juana; San-Martin, Aurelio

    2011-07-01

    Biological transformation of the meroditerpenoid, stypotriol triacetate ( 1) by the fungi Aspergillus niger, Cunninghamella elegans, Gibberella fujikuroi and Mucor plumbeus was studied. The incubation of 1 with A. niger yielded the new compound 6',14-diacetoxy-stypol-4,5-dione ( 2) whose structure was established by 1H, 13C and 2D NMR and supported by DFT/GIAO.

  7. Production of Lytic Enzymes by Trichoderma Isolates during in vitro Antagonism with Aspergillus Niger, The Causal Agent of Collar ROT of Peanut.

    PubMed

    Gajera, H P; Vakharia, D N

    2012-01-01

    Twelve isolates of Trichoderma (six of T. harzianum, five of T. viride, one of T. virens), which reduced variably the incidence of collar rot disease caused in peanut by Aspergillus niger Van Tieghem, were evaluated for their potential to produce lytic enzymes during in vitro antagonism. T. viride 60 inhibited highest (86.2%) growth of test fungus followed by T. harzianum 2J (80.4%) at 6 days after inoculation (DAI) on PDA media. The specific activities of chitinase, ?-1,3-glucanase and protease were 11, 3.46 and 9 folds higher in T6 antagonist (T. viride 60 and A. niger interactions) followed by 8.72, 2.85 and 9 folds in T8antagonist (T. harzianum 2J and A. niger interactions), respectively, compared to the activity produced by control petri plate T13 (A. niger alone) at 6 DAI. Activity of these lytic enzymes induced in antagonists' plates comprises the growth of Trichoderma isolates. However, cellulase and poly galacturonase were found least amount in these antagonists treatment. A significant positive correlation (p=0.01) between percentage growth inhibition of test fungus and lytic enzymes - (chitinase, ?-1,3-glucanase and protease) in the culture medium of antagonist treatment established a relationship to inhibit growth of fungal pathogen by increasing the levels of these enzymes. Among the Trichoderma isolates, T. viride 60 was found best strain to be used in biological control of plant pathogen A. niger. PMID:24031802

  8. Isolation, molecular cloning and expression of cellobiohydrolase B (CbhB) from Aspergillus niger in Escherichia coli

    NASA Astrophysics Data System (ADS)

    Woon, J. S. K.; Murad, A. M. A.; Abu Bakar, F. D.

    2015-09-01

    A cellobiohydrolase B (CbhB) from Aspergillus niger ATCC 10574 was cloned and expressed in E. coli. CbhB has an open reading frame of 1611 bp encoding a putative polypeptide of 536 amino acids. Analysis of the encoded polypeptide predicted a molecular mass of 56.2 kDa, a cellulose binding module (CBM) and a catalytic module. In order to obtain the mRNA of cbhB, total RNA was extracted from A. niger cells induced by 1% Avicel. First strand cDNA was synthesized from total RNA via reverse transcription. The full length cDNA of cbhB was amplified by PCR and cloned into the cloning vector, pGEM-T Easy. A comparison between genomic DNA and cDNA sequences of cbhB revealed that the gene is intronless. Upon the removal of the signal peptide, the cDNA of cbhB was cloned into the expression vector pET-32b. However, the recombinant CbhB was expressed in Escherichia coli Origami DE3 as an insoluble protein. A homology model of CbhB predicted the presence of nine disulfide bonds in the protein structure which may have contributed to the improper folding of the protein and thus, resulting in inclusion bodies in E. coli.

  9. Biotransformation of artemisinin by Aspergillus niger.

    PubMed

    Zhan, Yulian; Liu, Hua; Wu, Yunshan; Wei, Pingying; Chen, Zhencheng; Williamson, John S

    2015-04-01

    Biotransformation of artemisinin (1) by Aspergillus niger was investigated. During 12 days at 28 °C and pH 6.0, A. niger transformed artemisinin into four products. They were identified as 3β-hydroxy-4,12-epoxy-1-deoxyartemisinin (2), artemisinin G (3), 3,13-epoxyartemisinin (4), and 4α-hydroxy-1-deoxyartemisinin (5). Products 2 and 4 are new compounds and are being reported here for the first time. The product 4 contains a 3,13-epoxy structure. This is the first report of epoxidation of artemisinin using microbial strains. The product 4 still has an intact peroxide bridge and therefore can be used as a scaffold for further structural modification using chemical and biological methods in the search for new antimalarial drugs. PMID:25712678

  10. Biotransformation of swertiamarin by Aspergillus niger.

    PubMed

    Chang, Jun; Zhou, Bin

    2015-11-01

    The biotransforamtion of swertiamarin has been carried out using Aspergillus niger. The results showed that 60% swertiamarin were metabolized into two metabolites during the 5 days of biotransformation. The metabolites were identified as erythrocentaurin and 5-ethylidene-8-hydroxy-3,4,5,6,7,8-hexahydro-1Hpyrano[3,4-c]-pyridine-1-one, a novel alkaloid, with NMR and MS. The hydrolysis of glucosidic bond catalyzed by β-D-glucosidase was found to be the rate-limiting reaction in pathway of biotransformation of swertiamarin. PMID:26639489

  11. Retting of Flax by Aspergillus niger.

    PubMed

    De Frana, F P; Rosemberg, J A; De Jesus, A M

    1969-01-01

    In this study, retting was carried out by Aspergillus niger. The pH, galacturonic acid (GA), and total reducing sugar were determined; the end point was identified by the classic empirical processes and by the maximal GA content of the retting water. The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes. Control of total acidity was not required, since the pH remained close to neutrality throughout the entire process. PMID:16349835

  12. Retting of Flax by Aspergillus niger

    PubMed Central

    De Frana, F. P.; Rosemberg, J. A.; De Jesus, A. M.

    1969-01-01

    In this study, retting was carried out by Aspergillus niger. The pH, galacturonic acid (GA), and total reducing sugar were determined; the end point was identified by the classic empirical processes and by the maximal GA content of the retting water. The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes. Control of total acidity was not required, since the pH remained close to neutrality throughout the entire process. PMID:16349835

  13. Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B?.

    PubMed

    Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan

    2014-11-01

    Aflatoxin B?, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B? after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B? after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B? degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B? was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B? degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B? degradation by the supernatant were examined. Results indicated that aflatoxin B? degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment. PMID:25401962

  14. Draft Genome Sequence of Aspergillus niger Strain An76.

    PubMed

    Gong, Weili; Cheng, Zhi; Zhang, Huaiqiang; Liu, Lin; Gao, Peiji; Wang, Lushan

    2016-01-01

    The filamentous fungus Aspergillus niger has become one of the most important fungi in industrial biotechnology, and it can efficiently secrete both polysaccharide-degrading enzymes and organic acids. We report here the 6,074,961,332-bp draft sequence of A. niger strain An76, and the findings provide important information related to its lignocellulose-degrading ability. PMID:26893421

  15. Draft Genome Sequence of Aspergillus niger Strain An76

    PubMed Central

    Gong, Weili; Cheng, Zhi; Zhang, Huaiqiang; Liu, Lin; Gao, Peiji

    2016-01-01

    The filamentous fungus Aspergillus niger has become one of the most important fungi in industrial biotechnology, and it can efficiently secrete both polysaccharide-degrading enzymes and organic acids. We report here the 6,074,961,332-bp draft sequence of A. niger strain An76, and the findings provide important information related to its lignocellulose-degrading ability. PMID:26893421

  16. Antifungal activity of strains of lactic acid bacteria isolated from a semolina ecosystem against Penicillium roqueforti, Aspergillus niger and Endomyces fibuliger contaminating bakery products.

    PubMed

    Valerio, Francesca; Favilla, Mara; De Bellis, Palmira; Sisto, Angelo; de Candia, Silvia; Lavermicocca, Paola

    2009-09-01

    Thirty samples of Italian durum wheat semolina and whole durum wheat semolina, generally used for the production of Southern Italy's traditional breads, were subjected to microbiological analysis in order to explore their lactic acid bacteria (LAB) diversity and to find strains with antifungal activity. A total of 125 presumptive LAB isolates (Gram-positive and catalase-negative) were characterized by repetitive extragenic palindromic-PCR (REP-PCR) and sequence analysis of the 16S rRNA gene, leading to the identification of the following species: Weissella confusa, Weissella cibaria, Leuconostoc citreum, Leuconostoc mesenteroides, Lactococcus lactis, Lactobacillus rossiae and Lactobacillus plantarum. The REP-PCR results delineated 17 different patterns whose cluster analysis clearly differentiated W. cibaria from W. confusa isolates. Seventeen strains, each characterized by a different REP-PCR pattern, were screened for their antifungal properties. They were grown in a flour-based medium, comparable to a real food system, and the resulting fermentation products (FPs) were tested against fungal species generally contaminating bakery products, Aspergillus niger, Penicillium roqueforti and Endomyces fibuliger. The results of the study indicated a strong inhibitory activity - comparable to that obtained with the common preservative calcium propionate (0.3% w/v) - of ten LAB strains against the most widespread contaminant of bakery products, P. roqueforti. The screening also highlighted the unexplored antifungal activity of L. citreum, L. rossiae and W. cibaria (1 strain), which inhibited all fungal strains to the same or a higher extent compared with calcium propionate. The fermentation products of these three strains were characterized by low pH values, and a high content of lactic and acetic acids. PMID:19243908

  17. Expression of the glucose oxidase gene from Aspergillus niger in Hansenula polymorpha and its use as a reporter gene to isolate regulatory mutations.

    PubMed

    Hodgkins, M; Mead, D; Ballance, D J; Goodey, A; Sudbery, P

    1993-06-01

    The glucose oxidase gene (god) from Aspergillus niger was expressed in Hansenula polymorpha using the methanol oxidase promoter and transcription termination region and the MF-alpha leader sequence from Saccharomyces cerevisiae to direct secretion. The expression cassette was cloned into the S. cerevisiae vector YEp13 and used to transform H. polymorpha strain A16. In the initial transformants plasmid replication was unstable, but was stabilized by a growth regime consisting of alternating cycles of selective and non-selective growth. The stabilized strain was grown to high cell density by fed-batch fermentation. Upon induction of the MOX promoter, glucose oxidase synthesis was initiated. At the end of the fermentation, the culture density was 76 g dry weight/1 and 108 IU/ml (0.5 g/1 or 0.65% dry weight) glucose oxidase was found in the culture medium; a further 86 IU/ml (0.43 g/1 or 0.56% dry weight) was recovered from the cell lysate. A plate assay was used to monitor glucose oxidase levels in individual colonies. This was then used to isolate mutants which showed abnormal regulation of god expression or which showed an altered pattern of secretion. One mutant, which showed increased production of glucose oxidase, was grown to high cell density by fed-batch fermentation (100.6 g/l) and produced 445 IU/ml(2.25 g/l or 2.2% dry weight) extracellularly and 76 IU/ml (0.38 g/l or 0.4% dry weight) intracellularly. The mutant thus not only increased total production but exported 83% of the total enzyme made compared to 55% in the parent strain. PMID:8346679

  18. Conversion of fusaric acid to fusarinol by Aspergillus niger: A detoxification reaction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Fusarium oxysporum causes wilt diseases of plants and produces a potent phytotoxin fusaric acid (FA) which is also toxic to many microorganisms. An Aspergillus strain with high tolerance to FA was isolated from soil. HPLC analysis of culture filtrates from A. niger grown with the addition...

  19. Characterization of the fumonisin B2 biosynthetic gene cluster in Aspergillus niger and A. awamori.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus niger and A. awamori strains isolated from grapes cultivated in Mediterranean basin were examined for fumonisin B2 (FB2) production and presence/absence of sequences within the fumonisin biosynthetic gene (fum) cluster. Presence of 13 regions in the fum cluster was evaluated by PCR assay...

  20. Aspergillus Niger Genomics: Past, Present and into the Future

    SciTech Connect

    Baker, Scott E.

    2006-09-01

    Aspergillus niger is a filamentous ascomycete fungus that is ubiquitous in the environment and has been implicated in opportunistic infections of humans. In addition to its role as an opportunistic human pathogen, A. niger is economically important as a fermentation organism used for the production of citric acid. Industrial citric acid production by A. niger represents one of the most efficient, highest yield bioprocesses in use currently by industry. The genome size of A. niger is estimated to be between 35.5 and 38.5 megabases (Mb) divided among eight chromosomes/linkage groups that vary in size from 3.5 - 6.6 Mb. Currently, there are three independent A. niger genome projects, an indication of the economic importance of this organism. The rich amount of data resulting from these multiple A. niger genome sequences will be used for basic and applied research programs applicable to fermentation process development, morphology and pathogenicity.

  1. Prospecting for the incidence of genes involved in ochratoxin and fumonisin biosynthesis in Brazilian strains of Aspergillus niger and Aspergillus welwitschiae.

    PubMed

    Massi, Fernanda Pelisson; Sartori, Daniele; de Souza Ferranti, Larissa; Iamanaka, Beatriz Thie; Taniwaki, Marta Hiromi; Vieira, Maria Lucia Carneiro; Fungaro, Maria Helena Pelegrinelli

    2016-03-16

    Aspergillus niger "aggregate" is an informal taxonomic rank that represents a group of species from the section Nigri. Among A. niger "aggregate" species Aspergillus niger sensu stricto and its cryptic species Aspergillus welwitschiae (=Aspergillus awamori sensu Perrone) are proven as ochratoxin A and fumonisin B2 producing species. A. niger has been frequently found in tropical and subtropical foods. A. welwitschiae is a new species, which was recently dismembered from the A. niger taxon. These species are morphologically very similar and molecular data are indispensable for their identification. A total of 175 Brazilian isolates previously identified as A. niger collected from dried fruits, Brazil nuts, coffee beans, grapes, cocoa and onions were investigated in this study. Based on partial calmodulin gene sequences about one-half of our isolates were identified as A. welwitschiae. This new species was the predominant species in onions analyzed in Brazil. A. niger and A. welwitschiae differ in their ability to produce ochratoxin A and fumonisin B2. Among A. niger isolates, approximately 32% were OTA producers, but in contrast only 1% of the A. welwitschiae isolates revealed the ability to produce ochratoxin A. Regarding fumonisin B2 production, there was a higher frequency of FB2 producing isolates in A. niger (74%) compared to A. welwitschiae (34%). Because not all A. niger and A. welwitschiae strains produce ochratoxin A and fumonisin B2, in this study a multiplex PCR was developed for detecting the presence of essential genes involved in ochratoxin (polyketide synthase and radHflavin-dependent halogenase) and fumonisin (α-oxoamine synthase) biosynthesis in the genome of A. niger and A. welwitschiae isolates. The frequency of strains harboring the mycotoxin genes was markedly different between A. niger and A. welwitschiae. All OTA producing isolates of A. niger and A. welwitschiae showed in their genome the pks and radH genes, and 95.2% of the nonproducing isolates did not contain these genes. The α-oxoamine synthase gene was detected in 100% and 36% of the A. niger and A. welwitschiae isolates, respectively. The loss of ochratoxin A production in A. niger and A. welwitschiae is highly associated with gene deletions within the ochratoxin biosynthetic gene cluster. The loss of fumonisin production in A. welwitschiae is associated with gene deletions within the fumonisin biosynthetic gene cluster, but this is not the case with A. niger. PMID:26803270

  2. Growth and hydrolase profiles can be used as characteristics to distinguish Aspergillus niger and other black aspergilli

    PubMed Central

    Meijer, M.; Houbraken, J.A.M.P.; Dalhuijsen, S.; Samson, R.A.; de Vries, R.P.

    2011-01-01

    Wild type Aspergillus niger isolates from different biotopes from all over the world were compared to each other and to the type strains of other black Aspergillus species with respect to growth and extracellular enzyme profiles. The origin of the A. niger isolate did not result in differences in growth profile with respect to monomeric or polymeric carbon sources. Differences were observed in the growth rate of the A. niger isolates, but these were observed on all carbon sources and not specific for a particular carbon source. In contrast, carbon source specific differences were observed between the different species. Aspergillus brasiliensis is the only species able to grow on D-galactose, and A. aculeatus had significantly better growth on Locus Bean gum than the other species. Only small differences were found in the extracellular enzyme profile of the A. niger isolates during growth on wheat bran, while large differences were observed in the profiles of the different black aspergilli. In addition, differences were observed in temperature profiles between the black Aspergillus species, but not between the A. niger isolates, demonstrating no isolate-specific adaptations to the environment. These data indicate that the local environment does not result in stable adaptations of A. niger with respect to growth profile or enzyme production, but that the potential is maintained irrespective of the environmental parameters. It also demonstrates that growth, extracellular protein and temperature profiles can be used for species identification within the group of black aspergilli. PMID:21892240

  3. Production of the Enzyme Naringinase by Aspergillus niger

    PubMed Central

    Bram, B.; Solomons, G. L.

    1965-01-01

    The formation of naringinase, a glycolytic enzyme produced by Aspergillus niger, is repressed by glucose. Production of the enzyme is decreased below pH 4.0 and is stimulated by the presence of substrate. Fermentation conditions are described which cause the formation of the enzyme in approximately a fivefold greater concentration than that previously described. PMID:5866035

  4. Utilization of brewery spent grain liquor by Aspergillus niger.

    PubMed

    Hang, Y D; Splittstoesser, D F; Woodams, E E

    1975-11-01

    Aspergillus niger was found capable of rapidly converting about 97% of the sugar from brewery spent grain liquor to fungal mass. The yield of dry mycelium, based on the sugar consumed, was approximately 57%. This fungus produced 1.10% titratable acid calculated as citric acid and reduced the biochemical oxygen demand by 96%. PMID:1200633

  5. Utilization of Brewery Spent Grain Liquor by Aspergillus niger1

    PubMed Central

    Hang, Y. D.; Splittstoesser, D. F.; Woodams, E. E.

    1975-01-01

    Aspergillus niger was found capable of rapidly converting about 97% of the sugar from brewery spent grain liquor to fungal mass. The yield of dry mycelium, based on the sugar consumed, was approximately 57%. This fungus produced 1.10% titratable acid calculated as citric acid and reduced the biochemical oxygen demand by 96%. PMID:1200633

  6. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1 †

    PubMed Central

    Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan

    2014-01-01

    Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B1 after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B1 degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B1 was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B1 degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B1 degradation by the supernatant were examined. Results indicated that aflatoxin B1 degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment. PMID:25401962

  7. Production of extremophilic bacterial cellulase enzymes in aspergillus niger.

    SciTech Connect

    Gladden, John Michael

    2013-09-01

    Enzymes can be used to catalyze a myriad of chemical reactions and are a cornerstone in the biotechnology industry. Enzymes have a wide range of uses, ranging from medicine with the production of pharmaceuticals to energy were they are applied to biofuel production. However, it is difficult to produce large quantities of enzymes, especially if they are non-native to the production host. Fortunately, filamentous fungi, such as Aspergillus niger, are broadly used in industry and show great potential for use a heterologous enzyme production hosts. Here, we present work outlining an effort to engineer A. niger to produce thermophilic bacterial cellulases relevant to lignocellulosic biofuel production.

  8. Production of cellulase and xylanase in a bubble gum column using immobilized Aspergillus niger KKS

    SciTech Connect

    Kang, Seong-Woo; Kim, Seung-Woo; Lee, Jin-Suk

    1995-05-01

    Aspergillus niger KKS, isolated from a farmland near Suwon, was immobilized on Celite and polyurethane foams. Enzyme activities produced by the immobilized cell system in a bubble column were higher than that of shake-flask culture. The enzyme productivities were twice as high. {Beta}-Glucosidase, {Beta}-xylosidase, and xylanase activities obtained in a bubble column were significant when the ground rice straw was used as a substrate. 9 refs., 2 figs., 3 tabs.

  9. Purification and immobilization of Aspergillus niger. beta. -xylosidase

    SciTech Connect

    Oguntimein, G.B.; Reilly, P.J.

    1980-01-01

    ..beta..-Xylosidase from a commercial Aspergillus niger preparation was purified by differential ammonium sulfate precipitation and either gel permeation or cation exchange chromatography, giving 16-fold purification in 32% yield for the first technique or 27-fold purification in 19% yield for the second. Enzyme prepared by this method was immobilized to 10 different carriers, but only when it was bound to alumina with TiCl/sub 4/ and to alkylamine porous silica with glutaraldehyde were substantial efficiencies and stabilities achieved.

  10. Analytical and computational approaches to define the Aspergillus niger secretome

    SciTech Connect

    Tsang, Adrian; Butler, Gregory D.; Powlowski, Justin; Panisko, Ellen A.; Baker, Scott E.

    2009-03-01

    We used computational and mass spectrometric approaches to characterize the Aspergillus niger secretome. The 11,200 gene models predicted in the genome of A. niger strain ATCC 1015 were the data source for the analysis. Depending on the computational methods used, 691 to 881 proteins were predicted to be secreted proteins. We cultured A. niger in six different media and analyzed the extracellular proteins produced using mass spectrometry. A total of 222 proteins were identified, with 39 proteins expressed under all six conditions and 74 proteins expressed under only one condition. The secreted proteins identified by mass spectrometry were used to guide the correction of about 20 gene models. Additional analysis focused on extracellular enzymes of interest for biomass processing. Of the 63 glycoside hydrolases predicted to be capable of hydrolyzing cellulose, hemicellulose or pectin, 94% of the exo-acting enzymes and only 18% of the endo-acting enzymes were experimentally detected.

  11. Six novel constitutive promoters for metabolic engineering of Aspergillus niger.

    PubMed

    Blumhoff, Marzena; Steiger, Matthias G; Marx, Hans; Mattanovich, Diethard; Sauer, Michael

    2013-01-01

    Genetic tools for the fine-tuning of gene expression levels are a prerequisite for rational strain optimization through metabolic engineering. While Aspergillus niger is an industrially important fungus, widely used for production of organic acids and heterologous proteins, the available genetic tool box for this organism is still rather limited. Here, we characterize six novel constitutive promoters of A. niger providing different expression levels. The selection of the promoters was based on published transcription data of A. niger. The promoter strength was determined with the ?-glucuronidase (gusA) reporter gene of Escherichia coli. The six promoters covered a GUS activity range of two to three orders of magnitude depending on the strain background. In order to demonstrate the power of the newly characterized promoters for metabolic engineering, they were used for heterologous expression of the cis-aconitate decarboxylase (cad1) gene of Aspergillus terreus, allowing the production of the building block chemical itaconic acid with A. niger. The CAD activity, dependent on the choice of promoter, showed a positive correlation with the specific productivity of itaconic acid. Product titers from the detection limit to up to 570mg/L proved that the set of constitutive promoters is a powerful tool for the fine-tuning of metabolic pathways for the improvement of industrial production processes. PMID:22707054

  12. Transcriptome analysis of Aspergillus niger grown on sugarcane bagasse

    PubMed Central

    2011-01-01

    Background Considering that the costs of cellulases and hemicellulases contribute substantially to the price of bioethanol, new studies aimed at understanding and improving cellulase efficiency and productivity are of paramount importance. Aspergillus niger has been shown to produce a wide spectrum of polysaccharide hydrolytic enzymes. To understand how to improve enzymatic cocktails that can hydrolyze pretreated sugarcane bagasse, we used a genomics approach to investigate which genes and pathways are transcriptionally modulated during growth of A. niger on steam-exploded sugarcane bagasse (SEB). Results Herein we report the main cellulase- and hemicellulase-encoding genes with increased expression during growth on SEB. We also sought to determine whether the mRNA accumulation of several SEB-induced genes encoding putative transporters is induced by xylose and dependent on glucose. We identified 18 (58% of A. niger predicted cellulases) and 21 (58% of A. niger predicted hemicellulases) cellulase- and hemicellulase-encoding genes, respectively, that were highly expressed during growth on SEB. Conclusions Degradation of sugarcane bagasse requires production of many different enzymes which are regulated by the type and complexity of the available substrate. Our presently reported work opens new possibilities for understanding sugarcane biomass saccharification by A. niger hydrolases and for the construction of more efficient enzymatic cocktails for second-generation bioethanol. PMID:22008461

  13. Expression of the Aspergillus terreus itaconic acid biosynthesis cluster in Aspergillus niger

    PubMed Central

    2014-01-01

    Background Aspergillus terreus is a natural producer of itaconic acid and is currently used to produce itaconic acid on an industrial scale. The metabolic process for itaconic acid biosynthesis is very similar to the production of citric acid in Aspergillus niger. However, a key enzyme in A. niger, cis-aconitate decarboxylase, is missing. The introduction of the A. terreus cadA gene in A. niger exploits the high level of citric acid production (over 200 g per liter) and theoretically can lead to production levels of over 135 g per liter of itaconic acid in A. niger. Given the potential for higher production levels in A. niger, production of itaconic acid in this host was investigated. Results Expression of Aspergillus terreus cis-aconitate decarboxylase in Aspergillus niger resulted in the production of a low concentration (0.05 g/L) of itaconic acid. Overexpression of codon-optimized genes for cis-aconitate decarboxylase, a mitochondrial transporter and a plasma membrane transporter in an oxaloacetate hydrolase and glucose oxidase deficient A. niger strain led to highly increased yields and itaconic acid production titers. At these higher production titers, the effect of the mitochondrial and plasma membrane transporters was much more pronounced, with levels being 5–8 times higher than previously described. Conclusions Itaconic acid can be produced in A. niger by the introduction of the A. terreus cis-aconitate decarboxylase encoding cadA gene. This results in a low itaconic acid production level, which can be increased by codon-optimization of the cadA gene for A. niger. A second crucial requirement for efficient production of itaconic acid is the expression of the A. terreus mttA gene, encoding a putative mitochondrial transporter. Expression of this transporter results in a twenty-fold increase in the secretion of itaconic acid. Expression of the A. terreus itaconic acid cluster consisting of the cadA gene, the mttA gene and the mfsA gene results in A. niger strains that produce over twenty five-fold higher levels of itaconic acid and show a twenty-fold increase in yield compared to a strain expressing only CadA. PMID:24438100

  14. Novel Antifungal Peptides Produced by Leuconostoc mesenteroides DU15 Effectively Inhibit Growth of Aspergillus niger.

    PubMed

    Muhialdin, Belal J; Hassan, Zaiton; Abu Bakar, Fatimah; Algboory, Hussein L; Saari, Nazamid

    2015-05-01

    The ability of Leuconostoc mesenteroides DU15 to produce antifungal peptides that inhibit growth of Aspergillus niger was evaluated under optimum growth conditions of 30 C for 48 h. The cell-free supernatant showed inhibitory activity against A. niger. Five novel peptides were isolated with the sequences GPFPL, YVPLF, LLHGVPLP, GPFPLEMTLGPT, and TVYPFPGPL as identified by de novo sequencing using PEAKS 6 software. Peptide LLHGVPLP was the only positively charged (cationic peptides) and peptide GPFPLEMTLGPT negatively charged (anionic), whereas the rest are neutral. The identified peptides had high hydrophobicity ratio and low molecular weights with amino acids sequences ranging from 5 to 12 residues. The mode of action of these peptides is observed under the scanning electron microscope and is due to cell lysis of fungi. This work reveals the potential of peptides from L. mesenteroides DU15 as natural antifungal preservatives in inhibiting the growth of A. niger that is implicated to the spoilage during storage. PMID:25847317

  15. Characterization of novel thermostable polygalacturonases from Penicillium brasilianum and Aspergillus niger.

    PubMed

    Zeni, Jamile; Pili, Jonaina; Cence, Karine; Toniazzo, Geciane; Treichel, Helen; Valduga, Eunice

    2015-12-01

    The aim of this research was the partial characterization of polygalacturonase (PG) extracts produced by a newly isolated Penicillium brasilianum and Aspergillus niger in submerged fermentation. The partial characterization of the crude enzymatic extracts showed optimum activity at pH 5.5 and 37C for both extracts. The results of temperature stability showed that PG from both microorganisms were more stable at 55C. However, the enzyme obtained by P. brasilianum presents a half-life time (t 1/2=693.10h), about one order of magnitude higher than those observed in for A. niger at 55C. In terms of pH stability, the PG produced by P. brasilianum presented higher stability at pH 4.0 and 5.0, while the PG from A. niger showed higher stability at pH 5.0. PMID:26341112

  16. Effect of gamma irradiation on the production of cell wall degrading enzymes by Aspergillus niger.

    PubMed

    Gherbawy, Y A

    1998-03-01

    Fungi occurring in Egyptian fruits in the City of Qena were studied. Results from the examination of 25 replicated samples of plums, pears and apples are reported. Examinations were carried out by direct plating after surface disinfection in a 0.5% (w/v) calcium hypochlorite solution on Czapek's-Dox agar. The dominant fungus found in the three types of fruit was Aspergillus niger, which was present in 88% of plum samples, 80% of pear samples and all of the apple samples. The lowest dose of gamma irradiation (1 MCi for 10 min) enhanced the three isolates of A. niger investigated to produce more biomass and polygalactronase, pectinmethylglacturonase, cellulase and protease. The higher doses (1 MCi for 20 and 30 min) were inhibitory to the growth of A. niger. PMID:9600619

  17. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  18. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger may be safely used... the carbohydrase and cellulase enzyme product. (d) The additive is used or intended for use as...

  19. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  20. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  1. 21 CFR 173.120 - Carbohydrase and cellulase derived from Aspergillus niger.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173.120 Carbohydrase and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from... Aspergillus niger from the carbohydrase and cellulase enzyme product. (d) The additive is used or intended...

  2. Contribution of arginase to manganese metabolism of Aspergillus niger.

    PubMed

    Keni, Sarita; Punekar, Narayan S

    2016-02-01

    Aspects of manganese metabolism during normal and acidogenic growth of Aspergillus niger were explored. Arginase from this fungus was a Mn[II]-enzyme. The contribution of the arginase protein towards A. niger manganese metabolism was investigated using arginase knockout (D-42) and arginase over-expressing (ΔXCA-29) strains of A. niger NCIM 565. The Mn[II] contents of various mycelial fractions were found in the order: D-42 strain < parent strain < ΔXCA-29 strain. While the soluble fraction forms 60 % of the total mycelial Mn[II] content, arginase accounted for a significant fraction of this soluble Mn[II] pool. Changes in the arginase levels affected the absolute mycelial Mn[II] content but not its distribution in the various mycelial fractions. The A. niger mycelia harvested from acidogenic growth media contain substantially less Mn[II] as compared to those from normal growth media. Nevertheless, acidogenic mycelia harbor considerable Mn[II] levels and a functional arginase. Altered levels of mycelial arginase protein did not significantly influence citric acid production. The relevance of arginase to cellular Mn[II] pool and homeostasis was evaluated and the results suggest that arginase regulation could occur via manganese availability. PMID:26679485

  3. Biotransformations of organic compounds mediated by cultures of Aspergillus niger.

    PubMed

    Parshikov, Igor A; Woodling, Kellie A; Sutherland, John B

    2015-09-01

    Many different organic compounds may be converted by microbial biotransformation to high-value products for the chemical and pharmaceutical industries. This review summarizes the use of strains of Aspergillus niger, a well-known filamentous fungus used in numerous biotechnological processes, for biochemical transformations of organic compounds. The substrates transformed include monocyclic, bicyclic, and polycyclic aromatic hydrocarbons; azaarenes, epoxides, chlorinated hydrocarbons, and other aliphatic and aromatic compounds. The types of reactions performed by A. niger, although not unique to this species, are extremely diverse. They include hydroxylation, oxidation of various functional groups, reduction of double bonds, demethylation, sulfation, epoxide hydrolysis, dechlorination, ring cleavage, and conjugation. Some of the products may be useful as new investigational drugs or chemical intermediates. PMID:26162670

  4. FluG affects secretion in colonies of Aspergillus niger.

    PubMed

    Wang, Fengfeng; Krijgsheld, Pauline; Hulsman, Marc; de Bekker, Charissa; Mller, Wally H; Reinders, Marcel; de Vries, Ronald P; Wsten, Han A B

    2015-01-01

    Colonies of Aspergillus niger are characterized by zonal heterogeneity in growth, sporulation, gene expression and secretion. For instance, the glucoamylase gene glaA is more highly expressed at the periphery of colonies when compared to the center. As a consequence, its encoded protein GlaA is mainly secreted at the outer part of the colony. Here, multiple copies of amyR were introduced in A. niger. Most transformants over-expressing this regulatory gene of amylolytic genes still displayed heterogeneous glaA expression and GlaA secretion. However, heterogeneity was abolished in transformant UU-A001.13 by expressing glaA and secreting GlaA throughout the mycelium. Sequencing the genome of UU-A001.13 revealed that transformation had been accompanied by deletion of part of the fluG gene and disrupting its 3' end by integration of a transformation vector. Inactivation of fluG in the wild-type background of A. niger also resulted in breakdown of starch under the whole colony. Asexual development of the ?fluG strain was not affected, unlike what was previously shown in Aspergillus nidulans. Genes encoding proteins with a signal sequence for secretion, including part of the amylolytic genes, were more often downregulated in the central zone of maltose-grown ?fluG colonies and upregulated in the intermediate part and periphery when compared to the wild-type. Together, these data indicate that FluG of A. niger is a repressor of secretion. PMID:25370014

  5. Steady-state shear characteristics of Aspergillus niger broths

    SciTech Connect

    Svihla, C.K.; Dronawat, S.N.; Hanley, T.R.

    1995-12-31

    It can be difficult to obtain reliable rheological data for filamentous fermentation broths using conventional instruments. One common approach is to measure the torque drawn by an impeller rotating in the suspension. Many previous workers have assumed that the applicable shear rate in such a device is related to the impeller speed by a fluid-independent constant determined by calibration with Newtonian and non-Newtonian fluids. The rheology of Aspergillus niger broths have been characterized using the impeller viscometer approach. The changes in the broth rheology were measured, and used to interpret the growth of biomass and the evolution of the microorganism morphology.

  6. Properties of soluble and immobilized Aspergillus niger. beta. -xylosidase

    SciTech Connect

    Oguntimein, G.B.; Reilly, P.J.

    1980-01-01

    Aspergillus niger ..beta..-xylosidase was characterized when in soluble form and when immobilized to alkylamine porous silica with glutaraldehyde and to alumina with titanium tetrachloride. Energies of activation averaged 13.4 kcal/mol for the soluble enzyme, 9.0 kcal/mol when immobilized to alumina, and 8.0 kcal/mol when bound to silica. The highest activity of all forms of ..beta..-xylosidase was found near pH 3. The soluble enzyme was highly stable at pH 4, where lowest rates of decay occurred, and temperatures of 65/sup 0/C and below.

  7. Antibiotic Extraction as a Recent Biocontrol Method for Aspergillus Niger andAspergillus Flavus Fungi in Ancient Egyptian mural paintings

    NASA Astrophysics Data System (ADS)

    Hemdan, R.; et al.

    Biodeterioration of mural paintings by Aspergillus niger and Aspergillus flavus Fungi has been proved in different mural paintings in Egypt nowadays. Several researches have studied the effect of fungi on mural paintings, the mechanism of interaction and methods of control. But none of these researches gives us the solution without causing a side effect. In this paper, for the first time, a recent treatment by antibiotic "6 penthyl α pyrone phenol" was applied as a successful technique for elimination of Aspergillus niger and Aspergillus flavus. On the other hand, it is favorable for cleaning Surfaces of Murals executed by tembera technique from the fungi metabolism which caused a black pigments on surfaces.

  8. Lethal Effects of Aspergillus niger against Mosquitoes Vector of Filaria, Malaria, and Dengue: A Liquid Mycoadulticide

    PubMed Central

    Singh, Gavendra; Prakash, Soam

    2012-01-01

    Aspergillus niger is a fungus of the genus Aspergillus. It has caused a disease called black mold on certain fruits and vegetables. The culture filtrates released from the A. niger ATCC 66566 were grown in Czapek dox broth (CDB) then filtered with flash chromatograph and were used for the bioassay after a growth of thirty days. The result demonstrated these mortalities with LC50, LC90, and LC99 values of Culex quinquefasciatus 0.76, 3.06, and 4.75, Anopheles stephensi 1.43, 3.2, and 3.86, and Aedes aegypti 1.43, 2.2, and 4.1??l/cm2, after exposure of seven hours. We have calculated significant LT90 values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0?hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides. PMID:22629156

  9. [Hydroxylation of indolyl-3-acetic acid by the fungus aspergillus niger IBFM-F-12].

    PubMed

    Koshcheenko, K A; Baklashova, T G; Kozlovskiĭ, A G; Arinbasarov, M U; Skriabin, G K

    1977-01-01

    Physiological and biochemical properties of the culture of Aspergillus niger IBPM F 12 carrying out hydroxylation IAA in the 4-, 5-, 6-positions of the indole nucleus were studied. The optimal composition of the medium for the cultivation was established. The transformation was performed by the washed fungal mycelium taken in the middle of the growth log-phase at a substrate concentration of I g/l. The correlation between the hydroxylase activity and pH, temperaure and biomass quantity was shown. The method of isolating 4-, 5- and 6-hydroxyindolyl-3-acetic acids in preparative amounts was developed. PMID:866301

  10. Phenethyl-alpha-pyrone derivatives and cyclodipeptides from a marine algous endophytic fungus Aspergillus niger EN-13.

    PubMed

    Zhang, Yi; Li, Xiao-Ming; Feng, Yan; Wang, Bin-Gui

    2010-07-01

    Two new phenethyl-alpha-pyrone derivatives including, isopyrophen (1) and aspergillusol (2), were characterised from the culture extract of Aspergillus niger EN-13, an endophytic fungus isolated from the inner tissue of the marine brown alga Colpomenia sinuosa. In addition, four known compounds, including a phenethyl-alpha-pyrone derivative (pyrophen, 3) and three cyclodipeptides (4-6), were also isolated and identified. The structures of these compounds were elucidated by spectroscopic methods. PMID:19606383

  11. ADOPTING SELECTED HYDROGEN BONDING AND IONIC INTERACTIONS FROM ASPERGILLUS FUMIGATUS PHYTASE STRUCTURE IMPROVES THE THERMOSTABILITY OF ASPERGILLUS NIGER PHYA PHYTASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although it has been widely used as a feed supplement to reduce manure phosphorus pollution of swine and poultry, Aspergillus niger PhyA phytase is unable to withstand heat inactivation during feed pelleting. Crystal structure comparisons with its close homolog, the thermostable Aspergillus fumigatu...

  12. Constitutive expression of fluorescent protein by Aspergillus var. niger and Aspergillus carbonarius to monitor fungal colonization in maize plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus niger and A. carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspe...

  13. Two-stage statistical medium optimization for augmented cellulase production via solid-state fermentation by newly isolated Aspergillus niger HN-1 and application of crude cellulase consortium in hydrolysis of rice straw.

    PubMed

    Sandhu, Simranjeet Kaur; Oberoi, Harinder Singh; Babbar, Neha; Miglani, Kanupriya; Chadha, Bhupinder Singh; Nanda, Dhiraj Kumar

    2013-12-26

    Cellulolytic enzyme production by newly isolated Aspergillus niger HN-1 was statistically optimized using Plackett-Burman and central composite design (CCD). Optimum concentrations of 2, 0.40, 0.01, and 0.60 g L (-1) for KH2PO4, urea, trace elements solution, and CaCl22H2O, respectively, were suggested by Design-Expert software. The two-stage optimization process led to a 3- and 2-fold increases in the filter paper cellulase (FP) and ?-glucosidase activities, respectively. FP, ?-glucosidase, endoglucanase, exopolygalaturonase, cellobiohydrolase, xylanase, ?-l-arabinofuranosidase, ?-xylosidase, and xylan esterase activities of 36.7 1.54 FPU gds(-1), 252.3 7.4 IU gds(-1), 416.3 22.8 IU gds(-1), 111.2 5.4 IU gds(-1), 8.9 0.50 IU gds(-1), 2593.5 78.9 IU gds(-1), 79.4 4.3 IU gds(-1), 180.8 9.3 IU gds(-1), and 288.7 11.8 IU gds(-1), respectively, were obtained through solid-state fermentation during the validation studies. Hydrolysis of alkali-treated rice straw with crude cellulases resulted in about 84% glucan to glucose, 89% xylan to xylose, and 91% arabinan to arabinose conversions, indicating potential for biomass hydrolysis by the crude cellulase consortium obtained in this study. PMID:24328069

  14. Type III polyketide synthase is involved in the biosynthesis of protocatechuic acid in Aspergillus niger.

    PubMed

    Lv, Yangyong; Xiao, Jing; Pan, Li

    2014-11-01

    Genomic studies have shown that not only plants but also filamentous fungi contain type III polyketide synthases. To study the function of type III polyketide synthase (AnPKSIII) in Aspergillus niger, a deletion strain (delAnPKSIII) and an overexpression strain (oeAnPKSIII) were constructed in A. niger MA169.4, a derivative of the wild-type (WT) A. niger ATCC 9029 that produces large quantities of gluconic acid. Alterations in the metabolites were analyzed by HPLC when the extract of the overexpression strain was compared with extracts of the WT and deletion strains. Protocatechuic acid (PCA; 3,4-dihydroxybenzoic acid, 3.2mg/l) was isolated and identified as the main product of AnPKSIII when inductively expressed in A. niger MA169.4. The molecular weight of PCA was 154.1 (m/z 153.1 [M-H](-)), was detected by ESI-MS in the negative ionization mode, and (1)H and (13)C NMR data confirmed its structure. PMID:25048233

  15. Tandem shock waves to enhance genetic transformation of Aspergillus niger.

    PubMed

    Loske, Achim M; Fernndez, Francisco; Magaa-Ortz, Denis; Coconi-Linares, Nancy; Ortz-Vzquez, Elizabeth; Gmez-Lim, Miguel A

    2014-08-01

    Filamentous fungi are used in several industries and in academia to produce antibiotics, metabolites, proteins and pharmaceutical compounds. The development of valuable strains usually requires the insertion of recombinant deoxyribonucleic acid; however, the protocols to transfer DNA to fungal cells are highly inefficient. Recently, underwater shock waves were successfully used to genetically transform filamentous fungi. The purpose of this research was to demonstrate that the efficiency of transformation can be improved significantly by enhancing acoustic cavitation using tandem (dual-pulse) shock waves. Results revealed that tandem pressure pulses, generated at a delay of 300 ?s, increased the transformation efficiency of Aspergillus niger up to 84% in comparison with conventional (single-pulse) shock waves. This methodology may also be useful to obtain new strains required in basic research and biotechnology. PMID:24680880

  16. New pathway for the biodegradation of indole in Aspergillus niger

    SciTech Connect

    Kamath, A.; Vaidyanathan, C.S. )

    1990-01-01

    Indole and its derivatives form a class of toxic recalcitrant environmental pollutants. The growth of Aspergillus niger was inhibited by very low concentrations (0.005 to 0.02%) of indole, even when 125- to 500-fold excess glucose was present in the medium. When 0.02% indole was added, the fungus showed a lag phase for about 30 h and the uptake of glucose was inhibited. Indole was metabolized by a new pathway via indoxyl (3-hydroxyindole), N-formylanthranilic acid, anthranilic acid, 2,3-dihydroxybenzoic acid, and catechol, which was further degraded by an ortho cleavage. The enzymes N-formylanthranilate deformylase, anthranilate hydroxylase, 2,3-dihydroxybenzoate decarboxylase, and catechol dioxygenase were induced by indole as early as after 5 h of growth, and their activities were demonstrated in a cell-free system.

  17. In-silico analysis of Aspergillus niger beta-glucosidases

    NASA Astrophysics Data System (ADS)

    Yeo S., L.; Shazilah, K.; Suhaila, S.; Abu Bakar F., D.; Murad A. M., A.

    2014-09-01

    Genomic data mining was carried out and revealed a total of seventeen β-glucosidases in filamentous fungi Aspergillus niger. Two of them belonged to glycoside hydrolase family 1 (GH1) while the rest belonged to genes in family 3 (GH3). These proteins were then named according to the nomenclature as proposed by the International Union of Biochemistry (IUB), starting from the lowest pI and glycoside hydrolase family. Their properties were predicted using various bionformatic tools showing the presence of domains for signal peptide and active sites. Interestingly, one particular domain, PA14 (protective antigen) was present in four of the enzymes, predicted to be involved in carbohydrate binding. A phylogenetic tree grouped the two glycoside hydrolase families with GH1 and GH3 related organisms. This study showed that the various domains present in these β-glucosidases are postulated to be crucial for the survival of this fungus, as supported by other analysis.

  18. Tailing of thermal inactivation curve of Aspergillus niger spores.

    PubMed Central

    Fujikawa, H; Itoh, T

    1996-01-01

    The nonlinear thermal inactivation of Aspergillus niger spores in phosphate-citrate buffer was studied. The thermal inactivation pattern of the spore consisted of a shoulder, an accelerated decline, and a tail at various constant temperatures around 60 degrees C. The pattern fitted a thermotolerant subpopulation model. In the model, we postulated that some spores in the initial population had become thermotolerant at a certain ratio during heating. The model parameters including the rate coefficients, the time lag, and the existence ratio of thermotolerant cells were analyzed at various temperatures. The tailing was not observed at an initial concentration below 10(3) cells per ml. Cells cultured from thermotolerant cells showed an inactivation pattern similar to that of the original cells. Also, cells at the second heating showed the same thermotolerance as or were slightly more thermosensitive than the original cells. Intermittent heating was found to be effective to inactivate cells at a high concentration. PMID:8837430

  19. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    SciTech Connect

    Choudhury, Samrat Roy; Goswami, Arunava; Nair, Kishore K.; Kumar, Rajesh; Gopal, Madhuban; Devakumar, C.; Gogoi, Robin; Srivastava, Chitra; Subhramanyam, B. S.

    2010-10-04

    Elemental sulfur (S{sup 0}), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  20. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Choudhury, Samrat Roy; Nair, Kishore K.; Kumar, Rajesh; Gogoi, Robin; Srivastava, Chitra; Gopal, Madhuban; Subhramanyam, B. S.; devakumar, C.; Goswami, Arunava

    2010-10-01

    Elemental sulfur (S0), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  1. Catalytical Properties of Free and Immobilized Aspergillus niger Tannase

    PubMed Central

    Flores-Maltos, Abril; Rodríguez-Durán, Luis V.; Renovato, Jacqueline; Contreras, Juan C.; Rodríguez, Raúl; Aguilar, Cristóbal N.

    2011-01-01

    A fungal tannase was produced, recovered, and immobilized by entrapment in calcium alginate beads. Catalytical properties of the immobilized enzyme were compared with those of the free one. Tannase was produced intracellularly by the xerophilic fungus Aspergillus niger GH1 in a submerged fermentation system. Enzyme was recovered by cell disruption and the crude extract was partially purified. The catalytical properties of free and immobilized tannase were evaluated using tannic acid and methyl gallate as substrates. KM and Vmax values for free enzyme were very similar for both substrates. But, after immobilization, KM and Vmax values increased drastically using tannic acid as substrate. These results indicated that immobilized tannase is a better biocatalyst than free enzyme for applications on liquid systems with high tannin content, such as bioremediation of tannery or olive-mill wastewater. PMID:21918717

  2. Identification of Genes Associated with Morphology in Aspergillus niger by Using Suppression Subtractive Hybridization

    PubMed Central

    Dai, Ziyu; Mao, Xingxue; Magnuson, Jon K.; Lasure, Linda L.

    2004-01-01

    The morphology of citric acid production strains of Aspergillus niger is sensitive to a variety of factors, including the concentration of manganese (Mn2+). Upon increasing the Mn2+ concentration in A. niger (ATCC 11414) cultures to 14 ppb or higher, the morphology switches from pelleted to filamentous, accompanied by a rapid decline in citric acid production. The molecular mechanisms through which Mn2+ exerts effects on morphology and citric acid production in A. niger cultures have not been well defined, but our use of suppression subtractive hybridization has identified 22 genes responsive to Mn2+. Fifteen genes were differentially expressed when A. niger was grown in media containing 1,000 ppb of Mn2+ (filamentous form), and seven genes were expressed in 10 ppb of Mn2+ (pelleted form). Of the 15 filament-associated genes, seven are novel and eight share 47 to 100% identity with genes from other organisms. Five of the pellet-associated genes are novel, and the other two genes encode a pepsin-type protease and polyubiquitin. All 10 genes with deduced functions are either involved in amino acid metabolism-protein catabolism or cell regulatory processes. Northern blot analysis showed that the transcripts of all 22 genes were rapidly enhanced or suppressed by Mn2+. Steady-state mRNA levels of six selected filament-associated genes remained high during 5 days of culture in a filamentous state and remained low under pelleted growth conditions. The opposite behavior was observed for four selected pellet-associated genes. The full-length cDNA of the filament-associated clone, Brsa-25, was isolated. Antisense expression of Brsa-25 permitted pelleted growth and increased citrate production at concentrations of Mn2+ that were higher than the parent strain could tolerate. These results suggest the involvement of the newly isolated genes in the regulation of A. niger morphology. PMID:15066846

  3. Identification of Genes Associated with Morphology in Aspergillus Niger by Using Suppression Subtractive Hybridization

    SciTech Connect

    Dai, Ziyu; Mao, Xingxue; Magnuson, Jon K.; Lasure, Linda L.

    2004-04-01

    The morphology of citric acid production strains of Aspergillus niger is sensitive to a variety of factors including the concentration of manganese (Mn2+). Upon increasing the Mn2+ concentration in A. niger (ATCC 11414) cultures to 14 ppb or higher, the morphology switches from pelleted to filamentous, accompanied by a rapid decline in citric acid production. Molecular mechanisms through which Mn2+ exerts effects on morphology and citric acid production in A. niger have not been well defined, but our use of suppression subtractive hybridization has identified 22 genes responsive to Mn2+. Fifteen genes were differentially expressed when A. niger was grown in media containing 1000 ppb Mn2+ (filamentous form) and seven genes in 10 ppb Mn2+ (pelleted form). Of the fifteen filamentous-associated genes, seven are novel and eight share 47-100% identity to genes from other organisms. Five of the pellet-associated genes are novel, and the other two genes encode a pepsin-type protease and polyubiquitin. All ten genes with deduced functions are either involved in amino acid metabolism/protein catabolism or cell regulatory processes. Northern-blot analysis showed that the transcripts of all 22 genes were rapidly enhanced or suppressed by Mn2+. Steady-state mRNA levels of six selected filamentous associated genes remained high during five days of culture in a filamentous state and low under pelleted growth conditions. The opposite behavior was observed for four selected pellet-associated genes. The full-length cDNA of the filamentous-associated clone, Brsa-25 was isolated. Antisense expression of Brsa-25 permitted pelleted growth and increased citrate production at higher concentrations of Mn2+ than could be tolerated by the parent strain. The results suggest the involvement of the newly isolated genes in regulation of A. niger morphology.

  4. Mapping the polysaccharide degradation potential of Aspergillus niger

    PubMed Central

    2012-01-01

    Background The degradation of plant materials by enzymes is an industry of increasing importance. For sustainable production of second generation biofuels and other products of industrial biotechnology, efficient degradation of non-edible plant polysaccharides such as hemicellulose is required. For each type of hemicellulose, a complex mixture of enzymes is required for complete conversion to fermentable monosaccharides. In plant-biomass degrading fungi, these enzymes are regulated and released by complex regulatory structures. In this study, we present a methodology for evaluating the potential of a given fungus for polysaccharide degradation. Results Through the compilation of information from 203 articles, we have systematized knowledge on the structure and degradation of 16 major types of plant polysaccharides to form a graphical overview. As a case example, we have combined this with a list of 188 genes coding for carbohydrate-active enzymes from Aspergillus niger, thus forming an analysis framework, which can be queried. Combination of this information network with gene expression analysis on mono- and polysaccharide substrates has allowed elucidation of concerted gene expression from this organism. One such example is the identification of a full set of extracellular polysaccharide-acting genes for the degradation of oat spelt xylan. Conclusions The mapping of plant polysaccharide structures along with the corresponding enzymatic activities is a powerful framework for expression analysis of carbohydrate-active enzymes. Applying this network-based approach, we provide the first genome-scale characterization of all genes coding for carbohydrate-active enzymes identified in A. niger. PMID:22799883

  5. Aspergillus niger as a new allergic agent associated with bindis and its efficacy against homeopathic drugs.

    PubMed

    Shrivastava, J N; Kumar, Ajay; Bhatnagar, V P

    2006-10-01

    Aspergillus was found as a dominant fungi to associate with brands of bindis. Among three potencies of four homeopathic drugs, Lycopodium 1M, Sulphur 1M, and Sepia 30 showed maximum inhibition zone of Aspergillus niger in inhibition zone technique. In poison food technique, Sepia 30M, Tellurium 30M, Sulphur 1M and Lycopodium 200 showed maximum percentage inhibition against A. niger PMID:17405335

  6. Induced Autolysis of Aspergillus oryzae (A. niger group)

    PubMed Central

    Emiliani, Ezio; de Davie, I. Ucha

    1962-01-01

    The examination of substances formed during induced autolysis by Aspergillus niger was continued in this work, which dealt in particular with carbohydrates. The autolysate contained a large amount of d-glucose (14 to 20% dry wt) and traces of glycolic aldehyde, dihydroxyacetone, ribose, xylose, and fructose. It also contained glycopeptides (about 10% dry wt), which were split from the cell wall during autolysis and which differed from one another in their level of polymerization and their composition. They were constituted by glucose and mannose, glucose and galactose, or mannose, glucose, and galactose (mannose being the most abundant in this case), and amino acids (chiefly alanine, serine, glutamic acid, and aspartic acid). During autolysis, only a part of the cell wall was dissolved, since it retained its shape. Upon further chemical hydrolysis, it produced mostly glucose and glucosamine, and smaller amounts of mannose, galactose, and amino acids. Presumably, glucomannoproteins and glucogalactoproteins were present in the intact cell as a macromolecular complex, constituting, together with chitin, the major part of the cell wall of Aspergillus. PMID:16349623

  7. GC--MS analysis reveals production of 2--Phenylethanol from Aspergillus niger endophytic in rose.

    PubMed

    Wani, Masood Ahmed; Sanjana, Kaul; Kumar, Dhar Manoj; Lal, Dhar Kanahya

    2010-02-01

    Endophytes include all organisms that during a variable period of their life, colonize the living internal tissues of their hosts without causing detectable symptoms. Several fungal endophytes have been isolated from a variety of plant species which have proved themselves as a rich source of secondary metabolites. The reported natural products from endophytes include antibiotics, immunosuppresants, anticancer compounds, antioxidant agents, etc. For the first time Rosa damacaena (rose) has been explored for its endophytes. The rose oil industry is the major identified deligence for its application in perfumery, flavouring, ointments, and pharmaceuticals including various herbal products. During the present investigation fungal endophytes were isolated from Rosa damacaena. A total of fifty four isolates were isolated out of which sixteen isolates were screened for the production of secondary metabolites. GCMS analysis reveals the production of 2-phenylethanol by one of the isolates JUBT 3M which was identified as Aspergillus niger. This is the first report of production of 2-phenylethanol from endophytic A. niger. 2-phenylethanol is an important constituent of rose oil constituting about 4.06% of rose oil. Presence of 2-phenylethanol indicates that the endophyte of rose may duplicate the biosynthesis of phenyl propanoids by rose plant. Besides this, the other commercial applications of phenylethanol include its use in antiseptics, disinfectants, anti-microbials and preservative in pharmaceuticals. PMID:20082377

  8. Molecular cloning and over-expression of a fructosyltransferase from Aspergillus niger QU10.

    PubMed

    Zhang, Guoqing; Yang, Jing; Shi, Jiaji; Qian, Shijun; Chao, Yapeng

    2015-04-01

    The main commercial production of fructooligosaccharides (FOS) comes from enzymatic transformation using sucrose as substrate by microbial enzyme fructosyltransferase. A fructosyltransferase genomic DNA was isolated from Aspergillus niger QU10 by PCR. The nucleotide sequence showed a 1 941 bp size, and has been submitted to GenBank (KF699529). The cDNA of the fructosyltransferase, containing an open reading frame of 1 887 bp, was further cloned by RT-PCR. The fructosyltransferase gene from Aspergillus niger was functionally expressed both in Escherichia coli and Pichia pastoris GS 115. The highest activity value for the construction with the ?-factor signal peptide reached 431 U/mL after 3 days of incubation. The recombinant enzyme is extensively glycosylated, and the active form is probably represented by a homodimer with an apparent molecular mass of 200 kDa as judged from mobility in seminative PAGE gels. The extracellular recombinant enzyme converted sucrose mostly to FOS, mainly 1-kestose and nystose, liberating glucose. FOS reached a maximal value and represented about 58% of total sugars present in the reaction mixture after 4 h reaction. The results suggest that the availability of recombinant Pichia pastoris as a new source of a FOS-producing enzyme might result of biotechnology interest for industrial application. PMID:26380408

  9. Fatty Acid Toxicity and Methyl Ketone Production in Aspergillus niger

    PubMed Central

    Lewis, Harold L.; Darnall, Dennis W.

    1970-01-01

    Vegetative hyphae of Aspergillus niger rapidly converted caproic acid into 2-pentanone. More caproic acid was required for maximal ketone production at alkaline as compared to acidic pH values. Further increases in caproate concentrations at each pH value tested (4.5, 5.5, 6.5, 7.5, and 8.5) resulted in inhibition of ketone production and O2 uptake. At alkaline pH values (8.5 and 7.5), oxygen uptake above the endogenous level and the production of 2-pentanone were parallel. This relationship did not hold at acidic pH values. At these pH values, ketone production continued (pH 6.5) or attained a maximum (pH 5.5 and 4.5) at caproate concentrations at which oxygen uptake was inhibited below endogenous levels. These data indicate that endogenous oxygen uptake was not inhibited by caproate at alkaline pH values at concentrations which did inhibit caproate oxidation and 2-pentanone production. Conversely, at acidic pH values, endogenous oxygen uptake was vigorously inhibited by caproate at concentrations at which exogenous fatty acid oxidation and 2-pentanone production were less affected. Simon-Beevers plots of these data showed that the undissociated acid was the permeant form of caproic acid. The fatty anion appeared to be the active or inhibitory form of caproate within the cell. Vegetative hyphae of A. niger were poorly buffered. Once the hyphae were washed and resuspended in phosphate buffer, they were well buffered towards inhibitory concentrations of caproic acid. These findings suggest that the primary mechanism(s) by which caproate inhibits oxygen uptake and ketone formation does not involve a change in the intracellular pH. PMID:5411757

  10. Biochemical and Molecular Characterization of Secreted ?-Xylosidase from Aspergillus niger*

    PubMed Central

    Scott-Craig, John S.; Borrusch, Melissa S.; Banerjee, Goutami; Harvey, Christopher M.; Walton, Jonathan D.

    2011-01-01

    ?-Linked xylose is a major component of xyloglucans in the cell walls of higher plants. An ?-xylosidase (AxlA) was purified from a commercial enzyme preparation from Aspergillus niger, and the encoding gene was identified. The protein is a member of glycosyl hydrolase family 31. It was active on p-nitrophenyl-?-d-xyloside, isoprimeverose, xyloglucan heptasaccharide (XXXG), and tamarind xyloglucan. When expressed in Pichia pastoris, AxlA had activity comparable to the native enzyme on pNP?X and IP despite apparent hyperglycosylation. The pH optimum of AxlA was between 3.0 and 4.0. AxlA together with ?-glucosidase depolymerized xyloglucan heptasaccharide. A combination of AxlA, ?-glucosidase, xyloglucanase, and ?-galactosidase in the optimal proportions of 51:5:19:25 or 59:5:11:25 could completely depolymerize tamarind XG to free Glc or Xyl, respectively. To the best of our knowledge, this is the first characterization of a secreted microbial ?-xylosidase. Secreted ?-xylosidases appear to be rare in nature, being absent from other tested commercial enzyme mixtures and from the genomes of most filamentous fungi. PMID:22033931

  11. Chemical modification of Aspergillus niger ?-glucosidase and its catalytic properties.

    PubMed

    Ahmed, Samia A; El-Shayeb, Nefisa M A; Hashem, Abdel-Gawad M; Saleh, Shireen A A; Abdel-Fattah, Ahmed F

    2015-03-01

    Aspergillus niger ?-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher K m (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t 1/2 (half-life) values of heat in-activation at 60 C and 70 C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t 1/2 of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p -Chloro Mercuri Benzoate ( p -CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of ?-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications. PMID:26221085

  12. Cloning and characterization of three Aspergillus niger promoters.

    PubMed

    Luo, X

    1995-09-22

    An Aspergillus niger (An) genomic library was constructed using the promoter-trap vector, pLX2A, which contains a hygromycin B (Hy) phosphotransferase-encoding gene (hph) for selection of DNA fragments with promoter activity. This library was transformed in Escherichia coli and 80,000 colonies were obtained, 94% of which contained inserts. Transformations of plasmid DNA from the library into An resulted in 53 Hy-resistant (HyR) colonies. Southern blot analysis of 21 transformants confirmed the integration of hph into the An genome. Using the sib selection procedure, three functional promoters, PX6, PX18 and PX21, were identified from this library. Both DNA strands of all three fragments were sequenced and their sequences showed no significant homology to those in the database. Comparison of the sequences of all known promoters from An suggested that C+T-rich stretches are probably important for promoter structures. The promoter activity was analysed further using beta-galactosidase (beta Gal) as a quantitative marker. The results suggest that while PX21 is a much stronger promoter than the known alpha-amylase promoter of A. oryzae, PX6 promotes only weak expression of beta Gal. PMID:7557461

  13. Chemical modification of Aspergillus niger ?-glucosidase and its catalytic properties

    PubMed Central

    Ahmed, Samia A.; El-Shayeb, Nefisa M.A.; Hashem, Abdel-Gawad M.; Saleh, Shireen A.A.; Abdel-Fattah, Ahmed F.

    2015-01-01

    Aspergillus niger ?-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation). The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein). Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy), a higher K m (Michaelis constant) and Vmax (maximal reaction rate), and improved thermal stability. The calculated t 1/2 (half-life) values of heat in-activation at 60 C and 70 C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t 1/2 of 200.0 and 49.5 min respectively). The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS) and p -Chloro Mercuri Benzoate ( p -CMB), while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively). The present work has established the potential of glycosylation to enhance the catalytic properties of ?-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications. PMID:26221085

  14. Some factors affecting tannase production by Aspergillus niger Van Tieghem

    PubMed Central

    Aboubakr, Hamada A.; El-Sahn, Malak A.; El-Banna, Amr A.

    2013-01-01

    One variable at a time procedure was used to evaluate the effect of qualitative variables on the production of tannase from Aspergillus niger Van Tieghem. These variables including: fermentation technique, agitation condition, tannins source, adding carbohydrates incorporation with tannic acid, nitrogen source type and divalent cations. Submerged fermentation under intermittent shaking gave the highest total tannase activity. Maximum extracellular tannase activity (305 units/50 mL) was attained in medium containing tannic acid as tannins source and sodium nitrate as nitrogen source at 30 °C for 96 h. All added carbohydrates showed significant adverse effects on the production of tannase. All tested divalent cations significantly decreased tannase production. Moreover, split plot design was carried out to study the effect of fermentation temperature and fermentation time on tannase production. The results indicated maximum tannase production (312.7 units/50 mL) at 35 °C for 96 h. In other words, increasing fermentation temperature from 30 °C to 35 °C resulted in increasing tannase production. PMID:24294255

  15. Genome shuffling of Aspergillus niger for improving transglycosylation activity.

    PubMed

    Li, Wei; Chen, Guiguang; Gu, Lingli; Zeng, Wei; Liang, Zhiqun

    2014-01-01

    Isomaltooligosaccharides (IMO), the glucosylsaccharides used as food additives, are made from saccharified starch by enzymes or microbial cells with transglycosylation activity. This study aimed to generate shuffled futants of Aspergillus niger with enhanced transglycosylation activity for industrial IMO production. The starting mutant population was generated by (60)Co-? radiation; mutants with higher transglycosylation activity were selected and subjected to recursive protoplast fusion. The resulting fusants were screened by a novel high-throughput method based on detecting non-fermentable reducing sugar. After three rounds of genome shuffling, the best performing strain GS3-3 was obtained, its transglycosylation activity (14.91 U/mL) was increased by 194.1 % compared to that of original strain C-6181. In fermentor test, transglycosylation activity of GS3-3 was obtained at 16.61 U/mL. The mycelia of GS3-3 were reused ten times to produce IMO syrup from liquefied cassava starch containing about 280 g/L total sugar within 4 days. The conversion of liquefied cassava starch to IMO was at 71.3-72.1 %, which was higher than the best conversion (68 %) ever reported. GS3-3 shows a great potential for industrial IMO production. PMID:24043449

  16. Phosphate solubilization and promotion of maize growth in a calcareous soil by Penicillium oxalicum P4 and Aspergillus niger P85

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternative tactics for improving phosphorus nutrition in crop production are needed in China and elsewhere as the over-application of phosphatic fertilizers can adversely impact agricultural sustainability. Penicillium oxalicum P4 and Aspergillus niger P85 were isolated from a calcareous soil in C...

  17. Flavone Biotransformation by Aspergillus niger and the Characterization of Two Newly Formed Metabolites

    PubMed Central

    Assawah, Suzan W.; El-Sharkawy, Saleh H.; Abdel-Salam, Amal

    2008-01-01

    Aspergillus niger isolated from Allium sativum was used at large scale fermentation (150 mg flavone/200 ml medium) to obtain suitable amounts of the products, efficient for identification. Then spectral analysis (UV, IR, 1H-NMR, 13C-NMR) and mass spectrometry were performed for the two products, which contributed to the identification process. The metabolite (1) was identified as 2'-hydroxydihydrochalcone, and the metabolite (2) was identified as 2'-hydroxyphenylmethylketone, which were more active than flavone itself. Antioxidant activities of the two isolated metabolites were tested compared with ascorbic acid. Antioxidant activity of metabolite (1) was recorded 64.58% which represented 79% of the antioxidant activity of ascorbic acid, and metabolite (2) was recorded 54.16% (67% of ascorbic acid activity). However, the antioxidant activity of flavone was recorded 37.50% which represented 46% of ascorbic acid activity. The transformed products of flavone have antimicrobial activity against Pseudomonas aeruginosa, Aspergillus flavus and Candida albicans, with MIC was recorded 250 µg/ml for metabolite (2) against all three organism and 500, 300, and 300 µg/ml for metabolite (1) against tested microorganisms (P. aeruginosa, Escherichia coli, Bacillus subtilis, and Klebsiella pneumonia, Fusarium moniliforme, A. flavus, Saccharomyces cerviceae, Kluveromyces lactis and C. albicans) at this order. PMID:23990746

  18. The infrared spectral transmittance of Aspergillus niger spore aggregated particle swarm

    NASA Astrophysics Data System (ADS)

    Zhao, Xinying; Hu, Yihua; Gu, Youlin; Li, Le

    2015-10-01

    Microorganism aggregated particle swarm, which is quite an important composition of complex media environment, can be developed as a new kind of infrared functional materials. Current researches mainly focus on the optical properties of single microorganism particle. As for the swarm, especially the microorganism aggregated particle swarm, a more accurate simulation model should be proposed to calculate its extinction effect. At the same time, certain parameters deserve to be discussed, which helps to better develop the microorganism aggregated particle swarm as a new kind of infrared functional materials. In this paper, take Aspergillus Niger spore as an example. On the one hand, a new calculation model is established. Firstly, the cluster-cluster aggregation (CCA) model is used to simulate the structure of Aspergillus Niger spore aggregated particle. Secondly, the single scattering extinction parameters for Aspergillus Niger spore aggregated particle are calculated by using the discrete dipole approximation (DDA) method. Thirdly, the transmittance of Aspergillus Niger spore aggregated particle swarm is simulated by using Monte Carlo method. On the other hand, based on the model proposed above, what influences can wavelength causes has been studied, including the spectral distribution of scattering intensity of Aspergillus Niger spore aggregated particle and the infrared spectral transmittance of the aggregated particle swarm within the range of 8~14μm incident infrared wavelengths. Numerical results indicate that the scattering intensity of Aspergillus Niger spore aggregated particle reduces with the increase of incident wavelengths at each scattering angle. Scattering energy mainly concentrates on the scattering angle between 0~40°, forward scattering has an obvious effect. In addition, the infrared transmittance of Aspergillus Niger spore aggregated particle swarm goes up with the increase of incident wavelengths. However, some turning points of the trend are associated with the absorption capacity of the swarm. When parameters of the swarm are set as follows: each Aspergillus Niger spore aggregated particle contains 40 original particles, the radius of original particle is 1.5μm, the density of aggregated particles is around 200/cm3, the measurement area is 4 meters thick, under conditions mentioned above, the infrared transmittance can be less than 10% between the incident wavelengths of 9.5~13μm. In the end, all the results provide the basis for better developing the microorganism aggregated particle swarm as a new kind of infrared functional materials and precisely choosing the effective defiladed infrared band.

  19. Role of pigmentation in protecting Aspergillus niger conidiospores against pulsed light radiation.

    PubMed

    Esbelin, Julia; Mallea, Sabine; Ram, Arthur F; Carlin, Frdric

    2013-01-01

    The photoprotective potential of fungus pigments was investigated by irradiating conidiospores of three Aspergillus niger strains possessing the same genetic background, but differing in their degree of pigmentation with pulsed light (PL) and monochromatic (254 nm) UV-C radiation. Spores of A. niger MA93.1 and JHP1.1 presenting, respectively, a fawn and a white pigmentation were more sensitive to PL and continuous UV-C radiation than the wild-type A. niger strain N402 possessing a dark pigment. Both spores of the dark A. niger N402 and the fawn-color mutant were equally resistant to moist heat at 56C while spores of the white-color mutant were highly sensitive. These results indicate that melanin protects pigmented spores of A. niger from PL. PMID:23278805

  20. Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger

    PubMed Central

    Lopes, Fernanda Cortez; Silva, Lucas André Dedavid e; Tichota, Deise Michele; Daroit, Daniel Joner; Velho, Renata Voltolini; Pereira, Jamile Queiroz; Corrêa, Ana Paula Folmer; Brandelli, Adriano

    2011-01-01

    A fungal isolate with capability to grow in keratinous substrate as only source of carbon and nitrogen was identified as Aspergillus niger using the sequencing of the ITS region of the rDNA. This strain produced a slightly acid keratinase and an acid protease during cultivation in feather meal. The peak of keratinolytic activity occurred in 48 h and the maximum proteolytic activity in 96 h. These enzymes were partly characterized as serine protease and aspartic protease, respectively. The effects of feather meal concentration and initial pH on enzyme production were evaluated using a central composite design combined with response surface methodology. The optimal conditions were determined as pH 5.0 for protease and 7.8 for keratinase and 20 g/L of feather meal, showing that both models were predictive. Production of keratinases by A. niger is a less-exploited field that might represent a novel and promising biotechnological application for this microorganism. PMID:22007293

  1. Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger.

    PubMed

    Lopes, Fernanda Cortez; Silva, Lucas Andr Dedavid E; Tichota, Deise Michele; Daroit, Daniel Joner; Velho, Renata Voltolini; Pereira, Jamile Queiroz; Corra, Ana Paula Folmer; Brandelli, Adriano

    2011-01-01

    A fungal isolate with capability to grow in keratinous substrate as only source of carbon and nitrogen was identified as Aspergillus niger using the sequencing of the ITS region of the rDNA. This strain produced a slightly acid keratinase and an acid protease during cultivation in feather meal. The peak of keratinolytic activity occurred in 48?h and the maximum proteolytic activity in 96?h. These enzymes were partly characterized as serine protease and aspartic protease, respectively. The effects of feather meal concentration and initial pH on enzyme production were evaluated using a central composite design combined with response surface methodology. The optimal conditions were determined as pH 5.0 for protease and 7.8 for keratinase and 20?g/L of feather meal, showing that both models were predictive. Production of keratinases by A. niger is a less-exploited field that might represent a novel and promising biotechnological application for this microorganism. PMID:22007293

  2. Novel Route for Agmatine Catabolism in Aspergillus niger Involves 4-Guanidinobutyrase

    PubMed Central

    Kumar, Sunil; Saragadam, Tejaswani

    2015-01-01

    Agmatine, a significant polyamine in bacteria and plants, mostly arises from the decarboxylation of arginine. The functional importance of agmatine in fungi is poorly understood. The metabolism of agmatine and related guanidinium group-containing compounds in Aspergillus niger was explored through growth, metabolite, and enzyme studies. The fungus was able to metabolize and grow on l-arginine, agmatine, or 4-guanidinobutyrate as the sole nitrogen source. Whereas arginase defined the only route for arginine catabolism, biochemical and bioinformatics approaches suggested the absence of arginine decarboxylase in A. niger. Efficient utilization by the parent strain and also by its arginase knockout implied an arginase-independent catabolic route for agmatine. Urea and 4-guanidinobutyrate were detected in the spent medium during growth on agmatine. The agmatine-grown A. niger mycelia contained significant levels of amine oxidase, 4-guanidinobutyraldehyde dehydrogenase, 4-guanidinobutyrase (GBase), and succinic semialdehyde dehydrogenase, but no agmatinase activity was detected. Taken together, the results support a novel route for agmatine utilization in A. niger. The catabolism of agmatine by way of 4-guanidinobutyrate to 4-aminobutyrate into the Krebs cycle is the first report of such a pathway in any organism. A. niger GBase peptide fragments were identified by tandem mass spectrometry analysis. The corresponding open reading frame from the A. niger NCIM 565 genome was located and cloned. Subsequent expression of GBase in both Escherichia coli and A. niger along with its disruption in A. niger functionally defined the GBase locus (gbu) in the A. niger genome. PMID:26048930

  3. Novel Route for Agmatine Catabolism in Aspergillus niger Involves 4-Guanidinobutyrase.

    PubMed

    Kumar, Sunil; Saragadam, Tejaswani; Punekar, Narayan S

    2015-08-15

    Agmatine, a significant polyamine in bacteria and plants, mostly arises from the decarboxylation of arginine. The functional importance of agmatine in fungi is poorly understood. The metabolism of agmatine and related guanidinium group-containing compounds in Aspergillus niger was explored through growth, metabolite, and enzyme studies. The fungus was able to metabolize and grow on l-arginine, agmatine, or 4-guanidinobutyrate as the sole nitrogen source. Whereas arginase defined the only route for arginine catabolism, biochemical and bioinformatics approaches suggested the absence of arginine decarboxylase in A. niger. Efficient utilization by the parent strain and also by its arginase knockout implied an arginase-independent catabolic route for agmatine. Urea and 4-guanidinobutyrate were detected in the spent medium during growth on agmatine. The agmatine-grown A. niger mycelia contained significant levels of amine oxidase, 4-guanidinobutyraldehyde dehydrogenase, 4-guanidinobutyrase (GBase), and succinic semialdehyde dehydrogenase, but no agmatinase activity was detected. Taken together, the results support a novel route for agmatine utilization in A. niger. The catabolism of agmatine by way of 4-guanidinobutyrate to 4-aminobutyrate into the Krebs cycle is the first report of such a pathway in any organism. A. niger GBase peptide fragments were identified by tandem mass spectrometry analysis. The corresponding open reading frame from the A. niger NCIM 565 genome was located and cloned. Subsequent expression of GBase in both Escherichia coli and A. niger along with its disruption in A. niger functionally defined the GBase locus (gbu) in the A. niger genome. PMID:26048930

  4. The biochemistry of citric acid accumulation by Aspergillus niger.

    PubMed

    Karaffa, L; Sndor, E; Fekete, E; Szentirmai, A

    2001-01-01

    Fungi, in particular Aspergilli, are well known for their potential to overproduce a variety of organic acids. These microorganisms have an intrinsic ability to accumulate these substances and it is generally believed that this provides the fungi with an ecological advantage, since they grow rather well at pH 3 to 5, while some species even tolerate pH values as low as 1.5. Organic acid production can be stimulated and in a number of cases conditions have been found that result in almost quantitative conversion of carbon substrate into acid. This is exploited in large-scale production of a number of organic acids like citric-, gluconic- and itaconic acid. Both in production volume as well as in knowledge available, citrate is by far the major organic acid. Citric acid (2-hydroxy-propane-1,2,3-tricarboxylic acid) is a true bulk product with an estimated global production of over 900 thousand tons in the year 2000. Till the beginning of the 20th century, it was exclusively extracted from lemons. Since the global market was dominated by an Italian cartel, other means of production were sought. Chemical synthesis was possible, but not suitable due to expensive raw materials and a complicated process with low yield. The discovery of citrate accumulation by Aspergillus niger led to a rapid development of a fermentation process, which only a decade later accounted for a large part of the global production. The application of citric acid is based on three of its properties: (1) acidity and buffer capacity, (2) taste and flavour, and (3) chelation of metal ions. Because of its three acid groups with pKa values of 3.1, 4.7 and 6.4, citrate is able to produce a very low pH in solution, but is also useful as a buffer over a broad range of pH values (2 to 7). Citric acid has a pleasant acid taste which leaves little aftertaste. It sometimes enhances flavour, but is also able to mask sweetness, such as the aspartame taste in diet beverages. Chelation of metal ions is a very important property that has led to applications such as antioxidant and preservative. Moreover, it is a "natural" substance and fully biodegradable. PMID:11791342

  5. Unfolding and Refolding of Aspergillus Niger PhyB Phytase: Role of Disulfide Bridges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Role of disulfide bridges in folding of Aspergillus niger phytase pH 2.5-optimum (PhyB) was investigated using dynamic light scattering (DLS). Guanidinium chloride (GuCl) at 1.0 M unfolded phytase; however, its removal by dialysis refolded the protein. Thiol reagent, tris (2-carboxyethyl) phosphin...

  6. SORPTION OF HEAVY METALS BY THE SOIL FUNGI ASPERGILLUS NIGER AND MUCOR ROUXII

    EPA Science Inventory

    Sorption of the nitrate salts of cadmium(II), copper (II), lanthanum(III) and silver (I) by two fungi, Aspergillus niger and Mucor rouxii, was evaluated using Fruendlich adsorption isotherms and energy dispersive X-ray electron microscopy. The linearized Freundlich isotherm descr...

  7. NIGERLYSINTM, HEMOLYSIN PRODUCED BY ASPERGILLUS NIGER, CAUSES LETHALITY OF PRIMARY RAT CORTICAL NEURONAL CELLS IN VITRO

    EPA Science Inventory

    Aspergillus niger produced a proteinaceous hemolysin, nigerlysinTM when incubated on sheep's blood agar at both 23° C and 37°C. Nigerlysin was purified from tryptic soy broth culture filtrate. Purified nigerlysin has a molecular weight of approximately 72 kDa, with an...

  8. NIGERLYSINTM, HEMOLYSIN PRODUCED BY ASPERGILLUS NIGER, CAUSES LETHALITY OF PRIMARY RAT CORTICAL NEURONAL CELLS IN VITRO

    EPA Science Inventory

    Aspergillus niger produced a proteinaceous hemolysin, nigerlysinTM when incubated on sheep's blood agar at both 23 C and 37C. Nigerlysin was purified from tryptic soy broth culture filtrate. Purified nigerlysin has a molecular weight of approximately 72 kDa, with an...

  9. Enzymatic Comparisons of Aspergillus niger PhyA and Escherichia coli AppA2 Phytases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was to compare three phytase activity assays and kinetics of Aspergillus niger PhyA and Escherichia coli AppA2 phytases expressed in Pichia pastoris at the observed stomach pH of 3.5. In Experiment 1, equivalent phytase activities in the crude preparations of PhyA and AppA2 were tested ...

  10. [Construction and application of black-box model for glucoamylase production by Aspergillus niger].

    PubMed

    Li, Lianwei; Lu, Hongzhong; Xia, Jianye; Chu, Ju; Zhuang, Yingping; Zhang, Siliang

    2015-07-01

    Carbon-limited continuous culture was used to study the relationship between the growth of Aspergillus niger and the production of glucoamylase. The result showed that when the specific growth rate was lower than 0.068 h(-1), the production of glucoamylase was growth-associated, when the specific growth rate was higher than 0.068 h(-1), the production of glucoamylase was not growth-associated. Based on the result of continuous culture, the Monod dynamics model of glucose consumption of A. niger was constructed, Combining Herbert-Pirt equation of glucose and oxygen consumption with Luedeking-Piret equation of enzyme production, the black-box model of Aspergillus niger for enzyme production was established. The exponential fed-batch culture was designed to control the specific growth rate at 0.05 h(-1) by using this model and the highest yield for glucoamylase production by A. niger reached 0.127 g glucoamylase/g glucose. The black-box model constructed in this study successfully described the glucoamylase production by A. niger and the result of the model fitted the measured value well. The black-box model could guide the design and optimization of glucoamylase production by A. niger. PMID:26647584

  11. Characterization of filamentous fungi isolated from Moroccan olive and olive cake: toxinogenic potential of Aspergillus strains.

    PubMed

    Roussos, Sevastianos; Zaouia, Nabila; Salih, Ghislane; Tantaoui-Elaraki, Abdelrhafour; Lamrani, Khadija; Cheheb, Mostafa; Hassouni, Hicham; Verh, Frderic; Perraud-Gaime, Isabelle; Augur, Christopher; Ismaili-Alaoui, Mustapha

    2006-05-01

    During the 2003 and 2004 olive oil production campaigns in Morocco, 136 samples from spoiled olive and olive cake were analyzed and 285 strains were isolated in pure culture. Strains included 167 mesophilic strains belonging to ten genera: Penicillium, Aspergillus, Geotrichum, Mucor, Rhizopus, Trichoderma, Alternaria, Acremonium, Humicola, Ulocladium as well as 118 thermophilic strains isolated in 2003 and 2004, mainly belonging to six species: Aspergillus fumigatus, Paecilomyces variotii, Mucor pusillus, Thermomyces lanuginosus, Humicola grisea, and Thermoascus aurantiacus. Penicillium and Aspergillus, respectively, 32.3 and 26.9% of total isolates represented the majority of mesophilic fungi isolated. When considering total strains (including thermotolerant strains) Aspergillus were the predominant strains isolated; follow-up studies on mycotoxins therefore focused primarily on aflatoxins (AFs) and ochratoxin A (OTA) from the latter strains. All isolated Aspergillus flavus strains (9) and Aspergillus niger strains (36) were studied in order to evaluate their capacity to produce AFs and OTA, respectively, when grown on starch-based culture media. Seven of the nine tested A. flavus strains isolated from olive and olive cake produced AF B1 at concentrations between 48 and 95 microg/kg of dry rice weight. As for the A. niger strains, 27 of the 36 strains produced OTA. PMID:16715545

  12. Phytase production by Aspergillus niger CFR 335 and Aspergillus ficuum SGA 01 through submerged and solid-state fermentation.

    PubMed

    Shivanna, Gunashree B; Venkateswaran, Govindarajulu

    2014-01-01

    Fermentation is one of the industrially important processes for the development of microbial metabolites that has immense applications in various fields. This has prompted to employ fermentation as a major technique in the production of phytase from microbial source. In this study, a comparison was made between submerged (SmF) and solid-state fermentations (SSF) for the production of phytase from Aspergillus niger CFR 335 and Aspergillus ficuum SGA 01. It was found that both the fungi were capable of producing maximum phytase on 5th day of incubation in both submerged and solid-state fermentation media. Aspergillus niger CFR 335 and A. ficuum produced a maximum of 60.6 U/gds and 38 U/gds of the enzyme, respectively, in wheat bran solid substrate medium. Enhancement in the enzyme level (76 and 50.7 U/gds) was found when grown in a combined solid substrate medium comprising wheat bran, rice bran, and groundnut cake in the ratio of 2 : 1 : 1. A maximum of 9.6 and 8.2 U/mL of enzyme activity was observed in SmF by A. niger CFR 335 and A.ficuum, respectively, when grown in potato dextrose broth. PMID:24688383

  13. Phytase Production by Aspergillus niger CFR 335 and Aspergillus ficuum SGA 01 through Submerged and Solid-State Fermentation

    PubMed Central

    Shivanna, Gunashree B.; Venkateswaran, Govindarajulu

    2014-01-01

    Fermentation is one of the industrially important processes for the development of microbial metabolites that has immense applications in various fields. This has prompted to employ fermentation as a major technique in the production of phytase from microbial source. In this study, a comparison was made between submerged (SmF) and solid-state fermentations (SSF) for the production of phytase from Aspergillus niger CFR 335 and Aspergillus ficuum SGA 01. It was found that both the fungi were capable of producing maximum phytase on 5th day of incubation in both submerged and solid-state fermentation media. Aspergillus niger CFR 335 and A. ficuum produced a maximum of 60.6?U/gds and 38?U/gds of the enzyme, respectively, in wheat bran solid substrate medium. Enhancement in the enzyme level (76 and 50.7?U/gds) was found when grown in a combined solid substrate medium comprising wheat bran, rice bran, and groundnut cake in the ratio of 2?:?1?:?1. A maximum of 9.6 and 8.2?U/mL of enzyme activity was observed in SmF by A. niger CFR 335 and A.ficuum, respectively, when grown in potato dextrose broth. PMID:24688383

  14. Overexpression of Aspergillus tubingensis faeA in protease-deficient Aspergillus niger enables ferulic acid production from plant material.

    PubMed

    Zwane, Eunice N; Rose, Shaunita H; van Zyl, Willem H; Rumbold, Karl; Viljoen-Bloom, Marinda

    2014-06-01

    The production of ferulic acid esterase involved in the release of ferulic acid side groups from xylan was investigated in strains of Aspergillus tubingensis, Aspergillus carneus, Aspergillus niger and Rhizopus oryzae. The highest activity on triticale bran as sole carbon source was observed with the A. tubingensis T8.4 strain, which produced a type A ferulic acid esterase active against methyl p-coumarate, methyl ferulate and methyl sinapate. The activity of the A. tubingensis ferulic acid esterase (AtFAEA) was inhibited twofold by glucose and induced twofold in the presence of maize bran. An initial accumulation of endoglucanase was followed by the production of endoxylanase, suggesting a combined action with ferulic acid esterase on maize bran. A genomic copy of the A. tubingensis faeA gene was cloned and expressed in A. niger D15#26 under the control of the A. niger gpd promoter. The recombinant strain has reduced protease activity and does not acidify the media, therefore promoting high-level expression of recombinant enzymes. It produced 13.5 U/ml FAEA after 5 days on autoclaved maize bran as sole carbon source, which was threefold higher than for the A. tubingensis donor strain. The recombinant AtFAEA was able to extract 50 % of the available ferulic acid from non-pretreated maize bran, making this enzyme suitable for the biological production of ferulic acid from lignocellulosic plant material. PMID:24664515

  15. The effects of agitation and aeration on the production of gluconic acid by Aspergillus niger

    SciTech Connect

    Dronawat, S.N.; Svihla, C.K.; Hanley, T.R.

    1995-12-31

    The effects of agitation and aeration in the production of gluconic acid by Aspergillus niger from a glucose medium were investigated. Experiments were conducted at aeration rates of 5.0 and 10.0 L/min. Four different agitation speeds were investigated for each aeration rate. Gluconic acid concentration and biomass concentration were analyzed, and the rate of consumption of substrate by A. niger was noted. The main purpose of this work was to find the optimal conditions of agitation and aeration for the growth of A. niger and production of gluconic acid in submerged culture in a batch fermentor at a bench-top scale. The oxygen-transfer rates at different agitation and aeration rates were calculated. The gluconic acid concentration and rate of growth of A. niger increased with increase in the agitation and aeration rates.

  16. Effects of Clitoria ternatea leaf extract on growth and morphogenesis of Aspergillus niger.

    PubMed

    Kamilla, L; Mansor, S M; Ramanathan, S; Sasidharan, S

    2009-08-01

    Clitoria ternatea is known for its antimicrobial activity but the antifungal effects of leaf extract on growth and morphogenesis of Aspergillus niger have not been observed. The extract showed a favorable antifungal activity against A. niger with a minimum inhibition concentration 0.8 mg/mL and minimum fungicidal concentration 1.6 mg/mL, respectively. The leaf extract exhibited considerable antifungal activity against filamentous fungi in a dose-dependent manner with 0.4 mg/mL IC50 value on hyphal growth of A. niger. The main changes observed under scanning electron microscopy after C. ternatea extract treatment were loss of cytoplasm in fungal hyphae and the hyphal wall and its diameter became markedly thinner, distorted, and resulted in cell wall disruption. In addition, conidiophore alterations were also observed when A. niger was treated with C. ternatea leaf extract. PMID:19575837

  17. Value addition of vegetable wastes by solid-state fermentation using Aspergillus niger for use in aquafeed industry.

    PubMed

    Rajesh, N; Imelda-Joseph; Raj, R Paul

    2010-11-01

    Vegetable waste typically has high moisture content and high levels of protein, vitamins and minerals. Its value as an agricultural feed can be enhanced through solid-state fermentation (SSF). Two experiments were conducted to evaluate the nutritional status of the products derived by SSF of a mixture of dried vegetable waste powder and oil cake mixture (soybean flour, wheat flour, groundnut oil cake and sesame oil cake at 4:3:2:1 ratio) using fungi Aspergillus niger S(1)4, a mangrove isolate, and A. niger NCIM 616. Fermentation was carried out for 9 days at 35% moisture level and neutral pH. Significant (p<0.05) increase in crude protein and amino acids were obtained in both the trials. The crude fat and crude fibre content showed significant reduction at the end of fermentation. Nitrogen free extract (NFE) showed a gradual decrease during the fermentation process. The results of the study suggest that the fermented product obtained on days 6 and 9 in case of A. niger S(1)4 and A. niger NCIM 616 respectively contained the highest levels of crude protein. PMID:20100652

  18. Value addition of vegetable wastes by solid-state fermentation using Aspergillus niger for use in aquafeed industry.

    TOXLINE Toxicology Bibliographic Information

    Rajesh N; Imelda-Joseph; Raj RP

    2010-11-01

    Vegetable waste typically has high moisture content and high levels of protein, vitamins and minerals. Its value as an agricultural feed can be enhanced through solid-state fermentation (SSF). Two experiments were conducted to evaluate the nutritional status of the products derived by SSF of a mixture of dried vegetable waste powder and oil cake mixture (soybean flour, wheat flour, groundnut oil cake and sesame oil cake at 4:3:2:1 ratio) using fungi Aspergillus niger S(1)4, a mangrove isolate, and A. niger NCIM 616. Fermentation was carried out for 9 days at 35% moisture level and neutral pH. Significant (p<0.05) increase in crude protein and amino acids were obtained in both the trials. The crude fat and crude fibre content showed significant reduction at the end of fermentation. Nitrogen free extract (NFE) showed a gradual decrease during the fermentation process. The results of the study suggest that the fermented product obtained on days 6 and 9 in case of A. niger S(1)4 and A. niger NCIM 616 respectively contained the highest levels of crude protein.

  19. Clinical and immunological reactions to Aspergillus niger among workers at a biotechnology plant.

    PubMed Central

    Topping, M D; Scarisbrick, D A; Luczynska, C M; Clarke, E C; Seaton, A

    1985-01-01

    The workforce at a biotechnology plant producing citric acid by fermentation of molasses with a strain of Aspergillus niger was studied. A combination of a respiratory questionnaire and clinical assessment identified 18 subjects (4.9% of the workforce) with work related bronchospasm. In nine of these evidence of sensitisation to A niger was obtained by skin prick tests and radioallergosorbent test (RAST) using as an antigen an extract of the A niger culture fluid from the process. Of the 325 subjects without work related bronchospasm, only nine (2.7%) had a positive prick test. There were no subjects with symptoms of extrinsic allergic alveolitis. Investigation into the source of the antigen showed that whereas, in some areas of the plant, A niger spores were present, in others there were no detectable spores. In these areas, however, extracts of filters from air samplers were shown by RAST inhibition to contain A niger antigens, indicating that the culture fluid was generating airborne antigen. RAST inhibition studies showed that the A niger culture fluid used in the process contained antigens that were not present in a commercially available A niger extract, thus emphasising the importance in this type of investigation of using antigens prepared from material to which the workers are exposed. PMID:3986142

  20. Expression of Lactate Dehydrogenase in Aspergillus niger for L-Lactic Acid Production

    PubMed Central

    Dave, Khyati K.; Punekar, Narayan S.

    2015-01-01

    Different engineered organisms have been used to produce L-lactate. Poor yields of lactate at low pH and expensive downstream processing remain as bottlenecks. Aspergillus niger is a prolific citrate producer and a remarkably acid tolerant fungus. Neither a functional lactate dehydrogenase (LDH) from nor lactate production by A. niger is reported. Its genome was also investigated for the presence of a functional ldh. The endogenous A. niger citrate synthase promoter relevant to A. niger acidogenic metabolism was employed to drive constitutive expression of mouse lactate dehydrogenase (mldhA). An appraisal of different branches of the A. niger pyruvate node guided the choice of mldhA for heterologous expression. A high copy number transformant C12 strain, displaying highest LDH specific activity, was analyzed under different growth conditions. The C12 strain produced 7.7 g/l of extracellular L-lactate from 60 g/l of glucose, in non-neutralizing minimal media. Significantly, lactate and citrate accumulated under two different growth conditions. Already an established acidogenic platform, A. niger now promises to be a valuable host for lactate production. PMID:26683313

  1. Comparing phosphorus mobilization strategies using Aspergillus niger for the mineral dissolution of three phosphate rocks.

    PubMed

    Schneider, K D; van Straaten, P; de Orduña, R Mira; Glasauer, S; Trevors, J; Fallow, D; Smith, P S

    2010-01-01

    Phosphorus deficiencies are limiting crop production in agricultural soils worldwide. Locally available sources of raw phosphate rock (PR) are being recognized for their potential role in soil fertility improvement. Phosphorus bioavailability is essential for the efficiency of PRs and can be increased by acid treatments. The utilization of organic acid producing micro-organisms, notably Aspergillus niger, presents a sustainable alternative to the use of strong inorganic acids, but acid production of A. niger strongly depends on the mineral content of the growth media. This study compared the phosphorus mobilization efficiency of two biological treatments, namely addition of acidic cell-free supernatants from A. niger cultivations to PRs and the direct cultivation of A. niger with PRs. The results show that addition of PR to cultivations leads to significant differences in the profile of organic acids produced by A. niger. Additions of PR, especially igneous rocks containing high amounts of iron and manganese, lead to reduced citric acid concentrations. In spite of these differences, phosphorus mobilization was similar between treatments, suggesting that the simpler direct cultivation method was not inferior. In addition to citric acid, it is suggested that oxalic acid contributes to PR solubilization in direct cultivations with A. niger, which would benefit farmers in developing countries where conventional fertilizers are not adequately accessible. PMID:19709342

  2. A biodegradation study of forest biomass by Aspergillus niger F7: correlation between enzymatic activity, hydrolytic percentage and biodegradation index

    PubMed Central

    Sharma, Nivedita; Kaushal, Richa; Gupta, Rakesh; Kumar, Sanjeev

    2012-01-01

    Aspergillus niger F7 isolated from soil was found to be the potent producer of cellulase and xylanase. The residue of forest species Toona ciliata, Celtris australis, Cedrus deodara and Pinus roxburghii was selected as substrate for biodegradation study due to its easy availability and wide use in industry. It was subjected to alkali (sodium hydroxide) treatment for enhancing its degradation. Biodegradation of forest waste by hydrolytic enzymes (cellulase and xylanase) secreted by A. niger under solid state fermentation (SSF) was explored. SSF of pretreated forest biomass was found to be superior over untreated forest biomass. Highest extracellular enzyme activity of 2201±23.91 U/g by A. niger was shown in pretreated C. australis wood resulting in 6.72±0.20 percent hydrolysis and 6.99±0.23 biodegradation index (BI). The lowest BI of 1.40±0.08 was observed in untreated saw dust of C. deodara having the least enzyme activity of 238±1.36 U/g of dry matter. Biodegradation of forest biomass under SSF was increased many folds when moistening agent i.e. tap water had been replaced with modified basal salt media (BSM). In BSM mediated degradation of forest waste with A. niger, extracellular enzyme activity was increased up to 4089±67.11 U/g of dry matter in turn resulting in higher BI of 15.4±0.41 and percent hydrolysis of 19.38±0.81 in pretreated C. australis wood. A. niger exhibited higher enzyme activity on pretreated biomass when moistened with modified BSM in this study. Statistically a positive correlation has been drawn between these three factors i.e. enzyme activity, BI and percent hydrolysis of forest biomass thus proving their direct relationship with each other. PMID:24031853

  3. The promoter of the glucoamylase-encoding gene of Aspergillus niger functions in Ustilago maydis.

    PubMed

    Smith, T L; Gaskell, J; Berka, R M; Yang, M; Henner, D J; Cullen, D

    1990-04-16

    Promoter sequences from the Aspergillus niger glucoamylase-encoding gene (glaA) were linked to the bacterial hygromycin (Hy) phosphotransferase-encoding gene (hph) and this chimeric marker was used to select Hy-resistant (HyR) Ustilago maydis transformants. This is an example of an Ascomycete promoter functioning in a Basidiomycete. HyR transformants varied with respect to copy number of integrated vector, mitotic stability, and tolerance to Hy. Only 216 bp of glaA promoter sequence is required for expression in U. maydis but this promoter is not induced by starch as it is in Aspergillus spp. The transcriptional start points are the same in U. maydis and A. niger. PMID:2112106

  4. Sub-inhibitory concentration of biogenic selenium nanoparticles lacks post antifungal effect for Aspergillus niger and Candida albicans and stimulates the growth of Aspergillus niger

    PubMed Central

    Kazempour, Zahra Bahri; Yazdi, Mohammad Hossein; Rafii, Fatemeh; Shahverdi, Ahmad Reza

    2013-01-01

    Background The antifungal activity of selenium nanoparticles (Se NPs) prepared by Klebsiella pneumoniae has been reported previously for different fungi. In the present study, freshly prepared Se NPs produced by K. pneumoniae were purified and characterized by transmission electron microscopy and Energy-Dispersive X-ray spectroscopy (EDS) and its post antifungal effects for two fungi were evaluated. Materials and Methods The minimum inhibitory concentrations (MICs) of Se NPs, determined by serial dilution were 250 g/ml for Aspergillus niger and 2,000 g/ml for Candida albicans. The effect of exposure of A. niger and C. albicans to Se NPs on later growth was evaluated by incubating the fungi for 1 hour at 25 C in media containing 0, 1, 2 and 4 x MIC of Se NPs and diluting the cultures 100 times with Se free medium. The kinetics of growth of the fungi in control cultures and in non-toxic Se NPs concentration of, 0.01 MIC, 0.02 MIC or 0.04 MIC were measured. Results The exposure of A. niger and C. albicans to 2 and 4 x MIC of Se NPs stimulated the growth of both fungi in the absence of toxic concentrations of Se. The strongest stimulation was observed for A. niger. Conclusion It is concluded that exposure to high concentration of the Se NPs did not have any post-inhibitory effect on A. niger and C. albicans and that trace amounts of this element promoted growth of both fungi in a dose- dependent-manner. The role of nanoparticles serving as needed trace elements and development of microorganism tolerance to nanoparticles should not be dismissed while considering therapeutic potential. PMID:23466957

  5. The phosphatidyl choline exchange properties in the cytosol of Aspergillus niger.

    PubMed

    Audigier-Petit, C; Letoublon, R; Fayet, Y; Got, R; Frot-Coutaz, J

    1986-01-01

    The presence of a PC-binding activity in the cytosol of Aspergillus niger van Tieghem has been established by measuring the reversible exchange of labeled DPC between an adsorbent (celite) and the cytosol. We have shown that this exchange is dependent upon the temperature and the ionic strength and it varies linearly with the protein concentration. This PC-binding activity is able to discriminate between DPC and some other phospholipids. PMID:3098303

  6. Application of immobilized tannase from Aspergillus niger for the removal of tannin from myrobalan juice.

    PubMed

    Srivastava, Anita; Kar, Rita

    2010-10-01

    Tannase produced optimally on an agroresidue by an Aspergillus niger isolate under submerged fermentation immobilized on sodium alginate beads with 93.6% efficiency was applied for tannin removal from myrobalan/aonla (Phyllanthus emblica) juice. The pH and temperature optima of the immobilized enzyme were found to be 5.4 and 40C while the corresponding values of the soluble enzyme were 5.8 and 35C. Maximum tannin removal of 73.6% was obtained at 40C and 150 rpm in 180 min with 36.6 U/ml of immobilized enzyme while the same amount of the soluble enzyme removed 45.2% of tannin at 37C and 150 rpm in the same time period. The immobilized beads could be used repeatedly till 7th cycle with 77% efficiency. When preserved at 6C the beads retained 71.7% of enzyme activity after 60 days. Reduction in vitamin C content, which is responsible for antioxidant property of the fruit, was minimum at only 2% during the treatment. PMID:22815571

  7. Characterization And Application Of Tannase Produced By Aspergillus Niger ITCC 6514.07 On Pomegranate Rind.

    PubMed

    Srivastava, Anita; Kar, Rita

    2009-10-01

    Extracellular tannase and gallic acid were produced optimally under submerged fermentation at 37 (0)C, 72 h, pH 5.0, 10 %(v/v) inoculum and 4 %(w/v) of the agroresidue pomegranate rind (PR) powder by an Aspergillus niger isolate. Tannic acid (1 %) stimulated the enzyme production by 245.9 % while with 0.5 % glucose, increase was marginal. Tannase production was inhibited by gallic acid and nitrogen sources such as NH4NO3, NH4Cl, KNO3, asparatic acid, urea and EDTA. The partially purified enzyme showed temperature and pH optima of 35 (0)C and 6.2 respectively which shifted to 40 (0)C and 5.8 on immobilization in alginate beads. Activity of the enzyme was inhibited by Zn(+2), Ca(+), Mn(+2), Mg(+2), Ba(+2)and Ag(+). The immobilized enzyme removed 68.8 % tannin from juice of aonla/myrobalan (Phyllanthus emblica), a tropical fruit, rich in vitamin C and other essential nutrients. The enzymatic treatment of the juice with minimum reduction in vitamin C is encouraging as non enzymatic treatments of myrobalan juice results in vitamin C removal. PMID:24031425

  8. Purification and characterization of a novel pyrethroid hydrolase from Aspergillus niger ZD11.

    PubMed

    Liang, Wei Q; Wang, Zhuo Y; Li, He; Wu, Pei C; Hu, Ji M; Luo, Na; Cao, Li X; Liu, Yu H

    2005-09-21

    The pyrethroid pesticides residues on foods and environmental contamination are a public safety concern. Pretreatment with pyrethroid hydrolase has the potential to alleviate the conditions. For this purpose, a fungus capable of using pyrethroid pesticides as a sole carbon source was isolated from the soil and characterized as Aspergillus niger ZD11. A novel pyrethroid hydrolase from cell extract was purified 41.5-fold to apparent homogeneity with 12.6% overall recovery. It is a monomeric structure with a molecular mass of 56 kDa, a pI of 5.4, and the enzyme activity was optimal at 45 degrees C and pH 6.5. The activities were strongly inhibited by Hg(2+), Ag(+), and rho-chloromercuribenzoate, whereas less pronounced effects (5-10% inhibition) were observed in the presence of the remaining divalent cations, the chelating agent EDTA and phenanthroline. The purified enzyme hydrolyzed various insecticides with similar carboxylester. trans-Permethrin is the preferred substrate. PMID:16159167

  9. Influence of pH on the expression of a recombinant epoxide hydrolase in Aspergillus niger.

    PubMed

    Naundorf, Andreas; Melzer, Guido; Archelas, Alain; Furstoss, Roland; Wohlgemuth, Roland

    2009-05-01

    The filamentous fungus Aspergillus niger was investigated in relation to its ability to produce a soluble epoxide hydrolase (EH) (E.C. 3.3.2.3) belonging to the microsomal EH family. This EH is a highly useful biocatalyst for kinetic resolution of racemic epoxides to give enantiopure building blocks. The production of EH on an industrial scale is still a major challenge and is linked to various optimization processes. In this work, production of protein and organic acids as a function of pH and cultivation time was investigated. The production of EH was highest (1000 U/L for p-nitrostyrene oxide) under acidic fermentation conditions (pH value of about 3). The metabolic flux toward production of organic acids and thereby acidification of the environment increased with an increasing pH value. At pH 7, nearly 50% of total carbon of the substrate was incorporated into organic acids, mainly gluconic and oxalic acid. Finally, the addition of protease inhibitors, antioxidants and cryoprotectants was investigated in relation to the stability of the EH during the downstream process. The determination of the pH dependence during fermentation and understanding of the parameters influencing the stability of the enzyme has allowed us to optimize intracellular expression. The EH has been easily isolated from the biomass with high activity (1.67 U/mg lyophilisate) in a robust process. PMID:19452475

  10. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger

    SciTech Connect

    Kubicek, C.P.; Schreferl-Kunar, G.; Woehrer, W.; Roehr, M.

    1988-03-01

    Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of P/sub i/ and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added /sup 14/CO/sub 2/ was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.

  11. Production of a bioflocculant from Aspergillus niger using palm oil mill effluent as carbon source.

    PubMed

    Aljuboori, Ahmad H Rajab; Uemura, Yoshimitsu; Osman, Noridah Binti; Yusup, Suzana

    2014-11-01

    This study evaluated the potential of bioflocculant production from Aspergillus niger using palm oil mill effluent (POME) as carbon source. The bioflocculant named PM-5 produced by A. niger showed a good flocculating capability and flocculating rate of 76.8% to kaolin suspension could be achieved at 60 h of culture time. Glutamic acid was the most favorable nitrogen source for A. niger in bioflocculant production at pH 6 and temperature 35 °C. The chemical composition of purified PM-5 was mainly carbohydrate and protein with 66.8% and 31.4%, respectively. Results showed the novel bioflocculant (PM-5) had high potential to treat river water from colloids and 63% of turbidity removal with the present of Ca(2+) ion. PMID:25189510

  12. Direct fermentation of potato starch to ethanol by cocultures of Aspergillus niger and Saccharomyces cerevisiae.

    PubMed Central

    Abouzied, M M; Reddy, C A

    1986-01-01

    Direct fermentation of unhydrolyzed potato starch to ethanol by monocultures of an amylolytic fungus, Aspergillus niger, and cocultures of A. niger and Saccharomyces cerevisiae was investigated. Amylolytic activity, rate and amount of starch utilization, and ethanol yields increased several-fold in coculture versus the monoculture due to the synergistic metabolic interactions between the species. Optimal ethanol yields were obtained in the pH range 5 to 6 and amylolytic activity was obtained in the pH range 5 to 8. Ethanol yields were maximal when fermentations were conducted anaerobically. Increasing S. cerevisiae inoculum in the coculture from 4 to 12% gave a dramatic increase in the rate of ethanol production, and ethanol yields of greater than 96% of the theoretical maximum were obtained within 2 days of fermentation. These results indicate that simultaneous fermentation of starch to ethanol can be conducted efficiently by using cocultures of the amylolytic fungus A. niger and a nonamylolytic sugar fermenter, S. cerevisiae. PMID:3539016

  13. Targeting enzymes to the right compartment: metabolic engineering for itaconic acid production by Aspergillus niger.

    PubMed

    Blumhoff, Marzena L; Steiger, Matthias G; Mattanovich, Diethard; Sauer, Michael

    2013-09-01

    Itaconic acid is an unsaturated dicarboxylic acid which has a high potential as a biochemical building block. It can be microbially produced from some Aspergillus species, such as Aspergillus itaconicus and Aspergillus terreus. However, the achieved titers are significantly lower as compared to the citric acid production by A. niger. Heterologous expression of cis-aconitate decarboxylase in A. niger leads to the accumulation of small amounts of itaconic acid. Additional expression of aconitase, the second enzyme metabolically linking citric acid and itaconic acid improves productivity. However, proper organelle targeting of the enzymes appears to be an important point to consider. Here we compare the mitochondrial expression with the cytosolic expression of cis-aconitate decarboxylase or aconitase in A. niger. Heterologous expression of both enzymes in the mitochondria doubles the productivity compared to strains which express the enzymes in the cytosol. It is essential to target enzymes to the correct compartment in order to establish a proper flux through a compartmentalized pathway. PMID:23727192

  14. Biocatalytic potential of laccase-like multicopper oxidases from Aspergillus niger

    PubMed Central

    2012-01-01

    Background Laccase-like multicopper oxidases have been reported in several Aspergillus species but they remain uncharacterized. The biocatalytic potential of the Aspergillus niger fungal pigment multicopper oxidases McoA and McoB and ascomycete laccase McoG was investigated. Results The laccase-like multicopper oxidases McoA, McoB and McoG from the commonly used cell factory Aspergillus niger were homologously expressed, purified and analyzed for their biocatalytic potential. All three recombinant enzymes were monomers with apparent molecular masses ranging from 80 to 110 kDa. McoA and McoG resulted to be blue, whereas McoB was yellow. The newly obtained oxidases displayed strongly different activities towards aromatic compounds and synthetic dyes. McoB exhibited high catalytic efficiency with N,N-dimethyl-p-phenylenediamine (DMPPDA) and 2,2-azino-di(3-ethylbenzthiazoline) sulfonic acid (ABTS), and appeared to be a promising biocatalyst. Besides oxidizing a variety of phenolic compounds, McoB catalyzed successfully the decolorization and detoxification of the widely used textile dye malachite green. Conclusions The A. niger McoA, McoB, and McoG enzymes showed clearly different catalytic properties. Yellow McoB showed broad substrate specificity, catalyzing the oxidation of several phenolic compounds commonly present in different industrial effluents. It also harbored high decolorization and detoxification activity with the synthetic dye malachite green, showing to have an interesting potential as a new industrial biocatalyst. PMID:23270588

  15. Induction of mutation in Aspergillus niger for conversion of cellulose into glucose

    SciTech Connect

    Helmi, S.; Khalil, A.E.; Tahoun, M.K.; Khairy, A.H.

    1991-12-31

    Plant wastes are very important part of biomass used and investigated for energy, chemical, and fuel production. Cellulose is the major renewable form of carbohydrate in the world, about 10{sup 11} tons of which is synthesized annually. For general use, it must be hydrolyzed first, either chemically or by cellulases derived from a few specialized microorganisms. Enzymes are acceptable environmentally but expensive to produce. Certainly, induction of mutations and selection of high cellulose microbial strains with significant adaptability to degrade cellulose to glucose is promising solutions. Induction of mutations in other fungi and Aspergillus sp. rather than Aspergillus niger was reported. Aspergillus ustus and Trichoderma harzianum were induced by gamma irradiation indicating mutants that excrete higher cellulose yields, particularly exocellobiohydrolase (Avicelase) than their respective wild types. Mutants from the celluiolytic fungus Penicillium pinophilum were induced by chemical and UV-irradiation. Enhancing the production of endo-1,4-{Beta}-D-glucanase (CMCase) and particularly {Beta}-glucosidase was obtained by gamma irradiation of Altemaria alternate. To overcome the lower activity of {beta}-glucosidase in certain fungi species rather than A. niger, mixed cultures of different species were tried. Thus, Aspergillus phonicis with Trichoderma reesei Rut 30, produced a cellulose complex that improved activity twofold over cellulose from Trichoderma alone.

  16. Aspernigrins with anti-HIV-1 activities from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30.

    PubMed

    Zhou, Xuefeng; Fang, Wei; Tan, Suiyi; Lin, Xiuping; Xun, Tianrong; Yang, Bingjie; Liu, Shuwen; Liu, Yonghong

    2016-01-15

    Two new 2-benzylpyridin-4-one containing metabolites, aspernigrins C (3) and D (4), together with six known compounds (1, 2, and 5-8), were isolated from the marine-derived fungus Aspergillus niger SCSIO Jcsw6F30. The structures of the new compounds were determined by NMR, MS, and optical rotation analyses. All the isolated compounds were evaluated for their inhibitory activities against infection with HIV-1 SF162 in TZM-bl cells. Malformin C (5) showed the strongest anti-HIV-1 activity with IC50 of 1.4±0.06μM (selectivity index, 11.4), meanwhile aspernigrin C (3) also exhibited potent activity with IC50 of 4.7±0.4μM (selectivity index, 7.5). PMID:26711143

  17. Infected Baerveldt Glaucoma Drainage Device by Aspergillus niger

    PubMed Central

    Salim, Nurul-Laila; Azhany, Yaakub; Abdul Rahman, Zaidah; Yusof, Roziawati; Liza-Sharmini, Ahmad Tajudin

    2015-01-01

    Fungal endophthalmitis is rare but may complicate glaucoma drainage device surgery. Management is challenging as the symptoms and signs may be subtle at initial presentation and the visual prognosis is usually poor due to its resistant nature to treatment. At present there is lesser experience with intravitreal injection of voriconazole as compared to Amphotericin B. We present a case of successfully treated Aspergillus endophthalmitis following Baerveldt glaucoma drainage device implantation with intravitreal and topical voriconazole. PMID:26064735

  18. Genome mining and functional genomics for siderophore production in Aspergillus niger.

    TOXLINE Toxicology Bibliographic Information

    Franken AC; Lechner BE; Werner ER; Haas H; Lokman BC; Ram AF; van den Hondel CA; de Weert S; Punt PJ

    2014-11-01

    Iron is an essential metal for many organisms, but the biologically relevant form of iron is scarce because of rapid oxidation resulting in low solubility. Simultaneously, excessive accumulation of iron is toxic. Consequently, iron uptake is a highly controlled process. In most fungal species, siderophores play a central role in iron handling. Siderophores are small iron-specific chelators that can be secreted to scavenge environmental iron or bind intracellular iron with high affinity. A second high-affinity iron uptake mechanism is reductive iron assimilation (RIA). As shown in Aspergillus fumigatus and Aspergillus nidulans, synthesis of siderophores in Aspergilli is predominantly under control of the transcription factors SreA and HapX, which are connected by a negative transcriptional feedback loop. Abolishing this fine-tuned regulation corroborates iron homeostasis, including heme biosynthesis, which could be biotechnologically of interest, e.g. the heterologous production of heme-dependent peroxidases. Aspergillus niger genome inspection identified orthologues of several genes relevant for RIA and siderophore metabolism, as well as sreA and hapX. Interestingly, genes related to synthesis of the common fungal extracellular siderophore triacetylfusarinine C were absent. Reverse-phase high-performance liquid chromatography (HPLC) confirmed the absence of triacetylfusarinine C, and demonstrated that the major secreted siderophores of A. niger are coprogen B and ferrichrome, which is also the dominant intracellular siderophore. In A. niger wild type grown under iron-replete conditions, the expression of genes involved in coprogen biosynthesis and RIA was low in the exponential growth phase but significantly induced during ascospore germination. Deletion of sreA in A. niger resulted in elevated iron uptake and increased cellular ferrichrome accumulation. Increased sensitivity toward phleomycin and high iron concentration reflected the toxic effects of excessive iron uptake. Moreover, SreA-deficiency resulted in increased accumulation of heme intermediates, but no significant increase in heme content. Together with the upregulation of several heme biosynthesis genes, these results reveal a complex heme regulatory mechanism.

  19. Heterologous expression, purification and characterization of nitrilase from Aspergillus niger K10

    PubMed Central

    2011-01-01

    Background Nitrilases attract increasing attention due to their utility in the mild hydrolysis of nitriles. According to activity and gene screening, filamentous fungi are a rich source of nitrilases distinct in evolution from their widely examined bacterial counterparts. However, fungal nitrilases have been less explored than the bacterial ones. Nitrilases are typically heterogeneous in their quaternary structures, forming short spirals and extended filaments, these features making their structural studies difficult. Results A nitrilase gene was amplified by PCR from the cDNA library of Aspergillus niger K10. The PCR product was ligated into expression vectors pET-30(+) and pRSET B to construct plasmids pOK101 and pOK102, respectively. The recombinant nitrilase (Nit-ANigRec) expressed in Escherichia coli BL21-Gold(DE3)(pOK101/pTf16) was purified with an about 2-fold increase in specific activity and 35% yield. The apparent subunit size was 42.7 kDa, which is approx. 4 kDa higher than that of the enzyme isolated from the native organism (Nit-ANigWT), indicating post-translational cleavage in the enzyme's native environment. Mass spectrometry analysis showed that a C-terminal peptide (Val327 - Asn356) was present in Nit-ANigRec but missing in Nit-ANigWT and Asp298-Val313 peptide was shortened to Asp298-Arg310 in Nit-ANigWT. The latter enzyme was thus truncated by 46 amino acids. Enzymes Nit-ANigRec and Nit-ANigWT differed in substrate specificity, acid/amide ratio, reaction optima and stability. Refolded recombinant enzyme stored for one month at 4C was fractionated by gel filtration, and fractions were examined by electron microscopy. The late fractions were further analyzed by analytical centrifugation and dynamic light scattering, and shown to consist of a rather homogeneous protein species composed of 12-16 subunits. This hypothesis was consistent with electron microscopy and our modelling of the multimeric nitrilase, which supports an arrangement of dimers into helical segments as a plausible structural solution. Conclusions The nitrilase from Aspergillus niger K10 is highly homologous (?86%) with proteins deduced from gene sequencing in Aspergillus and Penicillium genera. As the first of these proteins, it was shown to exhibit nitrilase activity towards organic nitriles. The comparison of the Nit-ANigRec and Nit-ANigWT suggested that the catalytic properties of nitrilases may be changed due to missing posttranslational cleavage of the former enzyme. Nit-ANigRec exhibits a lower tendency to form filaments and, moreover, the sample homogeneity can be further improved by in vitro protein refolding. The homogeneous protein species consisting of short spirals is expected to be more suitable for structural studies. PMID:21210990

  20. Hydrolysis of rice hull by crosslinked Aspergillus niger cellulase.

    PubMed

    Sharma, A; Khare, S K; Gupta, M N

    2001-07-01

    A. niger cellulase was crosslinked by glutaraldehyde to obtain a heat-stable enzyme preparation for rice hull cellulose hydrolysis. Under optimized crosslinking conditions of 0.12 M glutaraldehyde, pH 7.0, temperature 40 degrees C and at 45 min of crosslinking, a preparation having 15% more activity than free enzyme was obtained which also had considerable improvement in heat stability at 65 degrees C and 70 degrees C. Whereas the free enzyme lost 80% of its activity in 4 h at 65 degrees C, the crosslinked preparation lost only 30% activity. The crosslinked preparation hydrolyzed cellulosic biomass more effectively giving 2.2 mg/ml glucose and 52% corresponding saccharification in 4 h at 65 degrees C as compared to 14% saccharification by free enzyme under similar conditions. PMID:11341689

  1. Comparative Secretome Analysis of Aspergillus niger, Trichoderma reesei, and Penicillium oxalicum During Solid-State Fermentation.

    PubMed

    Gong, Weili; Zhang, Huaiqiang; Liu, Shijia; Zhang, Lili; Gao, Peiji; Chen, Guanjun; Wang, Lushan

    2015-11-01

    Filamentous fungi such as Aspergillus spp., Trichoderma spp., and Penicillium spp. are frequently used to produce high concentrations of lignocellulosic enzymes. This study examined the discrepancies in the compositions and dynamic changes in the extracellular enzyme systems secreted by Aspergillus niger ATCC1015, Trichoderma reesei QM9414, and Penicillium oxalicum 114-2 cultured on corn stover and wheat bran. The results revealed different types and an abundance of monosaccharides and oligosaccharides were released during incubation, which induced the secretion of diverse glycoside hydrolases. Both the enzyme activities and isozyme numbers of the three fungal strains increased with time. A total of 279, 161, and 183 secretory proteins were detected in A. niger, T. reesei, and P. oxalicum secretomes, respectively. In the A. niger secretomes, more enzymes involved in the degradation of (galacto)mannan, xyloglucan, and the backbone of pectin distributed mostly in dicots were detected. In comparison, although P. oxalicum 114-2 hardly secreted any xyloglucanases, the diversities of enzymes involved in the degradation of xylan and ?-(1,3;1,4)-D-glucan commonly found in monocots were higher. The cellulase system of P. oxalicum 114-2 was more balanced. The degradation preference provided a new perspective regarding the recomposition of lignocellulosic enzymes based on substrate types. PMID:26319683

  2. Mutualistic interaction between Salmonella enterica and Aspergillus niger and its effects on Zea mays colonization

    PubMed Central

    Balbontín, Roberto; Vlamakis, Hera; Kolter, Roberto

    2014-01-01

    Salmonella Typhimurium inhabits a variety of environments and is able to infect a broad range of hosts. Throughout its life cycle, some hosts can act as intermediates in the path to the infection of others. Aspergillus niger is a ubiquitous fungus that can often be found in soil or associated to plants and microbial consortia. Recently, S. Typhimurium was shown to establish biofilms on the hyphae of A. niger. In this work, we have found that this interaction is stable for weeks without a noticeable negative effect on either organism. Indeed, bacterial growth is promoted upon the establishment of the interaction. Moreover, bacterial biofilms protect the fungus from external insults such as the effects of the anti-fungal agent cycloheximide. Thus, the Salmonella–Aspergillus interaction can be defined as mutualistic. A tripartite gnotobiotic system involving the bacterium, the fungus and a plant revealed that co-colonization has a greater negative effect on plant growth than colonization by either organism in dividually. Strikingly, co-colonization also causes a reduction in plant invasion by S. Typhimurium. This work demonstrates that S. Typhimurium and A. niger establish a mutualistic interaction that alters bacterial colonization of plants and affects plant physiology. PMID:25351041

  3. Molecular Identification and Amphotericin B Susceptibility Testing of Clinical Isolates of Aspergillus From 11 Hospitals in Korea

    PubMed Central

    Heo, Min Seok; Choi, Min Ji; Park, Yeon-Joon; Lee, Hye Soo; Koo, Sun Hoe; Lee, Won Gil; Kim, Soo Hyun; Shin, Myung-Geun; Suh, Soon-Pal; Ryang, Dong-Wook

    2015-01-01

    Background We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method. Methods A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and ?-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values. Results ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by ?-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of ?2 g/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was ?75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%). Conclusions Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance. PMID:26354348

  4. Formation of Sclerotia and Production of Indoloterpenes by Aspergillus niger and Other Species in Section Nigri

    PubMed Central

    Frisvad, Jens C.; Petersen, Lene M.; Lyhne, E. Kirstine; Larsen, Thomas O.

    2014-01-01

    Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time. PMID:24736731

  5. Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose – Chitin Interactions

    PubMed Central

    Brandl, Maria T.; Carter, Michelle Q.; Parker, Craig T.; Chapman, Matthew R.; Huynh, Steven; Zhou, Yaguang

    2011-01-01

    Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose–chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens. PMID:22003399

  6. An Antifungal Role of Hydrogen Sulfide on the Postharvest Pathogens Aspergillus niger and Penicillium italicum

    PubMed Central

    Li, Yan-Hong; Hu, Liang-Bin; Yan, Hong; Liu, Yong-Sheng; Zhang, Hua

    2014-01-01

    In this research, the antifungal role of hydrogen sulfide (H2S) on the postharvest pathogens Aspergillus niger and Penicillium italicum growing on fruits and under culture conditions on defined media was investigated. Our results show that H2S, released by sodium hydrosulfide (NaHS) effectively reduced the postharvest decay of fruits induced by A. niger and P. italicum. Furthermore, H2S inhibited spore germination, germ tube elongation, mycelial growth, and produced abnormal mycelial contractions when the fungi were grown on defined media in Petri plates. Further studies showed that H2S could cause an increase in intracellular reactive oxygen species (ROS) in A. niger. In accordance with this observation we show that enzyme activities and the expression of superoxide dismutase (SOD) and catalase (CAT) genes in A. niger treated with H2S were lower than those in control. Moreover, H2S also significantly inhibited the growth of Saccharomyces cerevisiae, Rhizopus oryzae, the human pathogen Candida albicans, and several food-borne bacteria. We also found that short time exposure of H2S showed a microbicidal role rather than just inhibiting the growth of microbes. Taken together, this study suggests the potential value of H2S in reducing postharvest loss and food spoilage caused by microbe propagation. PMID:25101960

  7. Analysis of antimicrobial silver nanoparticles synthesized by coastal strains of Escherichia coli and Aspergillus niger.

    PubMed

    Kathiresan, Kandasamy; Alikunhi, Nabeel M; Pathmanaban, SriMahibala; Nabikhan, Asmathunisha; Kandasamy, Saravanakumar

    2010-12-01

    The present study investigated the extracellular biosynthesis of antimicrobial silver nanoparticles by Escherichia coli AUCAS 112 and Aspergillus niger AUCAS 237 derived from coastal mangrove sediment of southeast India. Both microbial species were able to produce silver nanoparticles, as confirmed by X-ray diffraction spectrum. The nanoparticles synthesized were mostly spherical, ranging in size from 5 to 20 nm for E. coli and from 5 to 35 nm for A. niger, as evident by transmission electron microscopy. Fourier transform spectroscopy revealed prominent peaks corresponding to amides I and II, indicating the presence of a protein for stabilizing the nanoparticles. Electrophoretic analysis revealed the presence of a prominent protein band with a molecular mass of 45 kDa for E. coli and 70 kDa for A. niger. The silver nanoparticles inhibited certain clinical pathogens, with antibacterial activity being more distinct than antifungal activity. The antimicrobial activity of E. coli was more pronounced than that of A. niger and was enhanced with the addition of polyvinyl alcohol as a stabilizing agent. This work highlighted the possibility of using microbes of coastal origin for synthesis of antimicrobial silver nanoparticles. PMID:21164575

  8. Repeat induced point mutation in two asexual fungi, Aspergillus niger and Penicillium chrysogenum.

    PubMed

    Braumann, Ilka; van den Berg, Marco; Kempken, Frank

    2008-05-01

    Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi. PMID:18347798

  9. Tolerance of arsenate-induced stress in Aspergillus niger, a possible candidate for bioremediation.

    PubMed

    Mukherjee, Abhishek; Das, Durba; Kumar Mondal, Sushil; Biswas, Raktim; Kumar Das, Tapan; Boujedaini, Naoual; Khuda-Bukhsh, Anisur R

    2010-02-01

    The arsenate tolerance limit in wild-type Aspergillus niger was determined. Because of its high tolerance, toxic effects of arsenate concentrations ranging from 25 to 100mg/L were investigated in regard to growth, intracellular thiols, proline and malondialdehyde (MDA) contents of wild-type A. niger. Cellular arsenate uptake was analyzed. Activities of catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and succinate dehydrogenase (SDH) were assayed. Growth of A. niger increased at 25mg/L arsenate, and it survived up to 100mg/L. MDA, intracellular thiol and proline contents increased up to a certain level. Activities of GR, SOD and CAT declined following a rise at low concentration(s); SDH activity decreased gradually with increased arsenate stress. Results indicated that A. niger had high arsenate uptake potential and could tolerate oxidative stress by manipulating its anti-oxidative defense mechanism, a property that may be exploited for removal of arsenate from contaminated aqua-environment. PMID:19811831

  10. Kinetics of cellobiose hydrolysis using cellobiase composites from Trichoderma reesei and Aspergillus niger

    SciTech Connect

    Grous, W.; Converse, A.; Grethlein, H.; Lynd, L.

    1985-01-01

    The enzymatic hydrolysis of cellulose to glucose involves the formation of cellobiose as an intermediate. It has been found necessary to add cellobiase from Aspergillus niger (NOVO) to the cellobiase component of Trichoderma reesei mutant Rut C-30 (Natick) cellulase enzymes in order to obtain after 48 h complete conversion of the cellobiose formed in the enzymatic hydrolysis of biomass. This study of the cellobiase activity of these two enzyme sources was undertaken as a first step in the formation of a kinetic model for cellulose hydrolysis that can be used in process design. In order to cover the full range of cellobiose concentrations, it was necessary to develop separate kinetic parameters for high- and low-concentration ranges of cellobiose for the enzymes from each organism. Competitive glucose inhibition was observed with the enzymes from both organisms. Substrate inhibition was observed only with the A. niger enzymes.

  11. Inhibition of Aspergillus niger Phosphate Solubilization by Fluoride Released from Rock Phosphate

    PubMed Central

    Mendes, Gilberto de Oliveira; Vassilev, Nikolay Bojkov; Bonduki, Victor Hugo Arajo; da Silva, Ivo Ribeiro; Ribeiro, Jos Ivo

    2013-01-01

    The simultaneous release of various chemical elements with inhibitory potential for phosphate solubilization from rock phosphate (RP) was studied in this work. Al, B, Ba, Ca, F, Fe, Mn, Mo, Na, Ni, Pb, Rb, Si, Sr, V, Zn, and Zr were released concomitantly with P during the solubilization of Arax RP (Brazil), but only F showed inhibitory effects on the process at the concentrations detected in the growth medium. Besides P solubilization, fluoride decreased fungal growth, citric acid production, and medium acidification by Aspergillus niger. At the maximum concentration found during Arax RP solubilization (22.9 mg F? per liter), fluoride decreased P solubilization by 55%. These findings show that fluoride negatively affects RP solubilization by A. niger through its inhibitory action on the fungal metabolism. Given that fluoride is a common component of RPs, the data presented here suggest that most of the microbial RP solubilization systems studied so far were probably operated under suboptimal conditions. PMID:23770895

  12. Aspergillus niger Enhance Bioactive Compounds Biosynthesis As Well As Expression of Functional Genes in Adventitious Roots of Glycyrrhiza uralensis Fisch.

    PubMed

    Li, Jing; Wang, Juan; Li, Jinxin; Liu, Dahui; Li, Hongfa; Gao, Wenyuan; Li, Jianli; Liu, Shujie

    2016-02-01

    In the present study, the culture conditions for the accumulation of Glycyrrhiza uralensis adventitious root metabolites in balloon-type bubble bioreactors (BTBBs) have been optimized. The results of the culture showed that the best culture conditions were a cone angle of 90° bioreactor and 0.4-0.6-0.4-vvm aeration volume. Aspergillus niger can be used as a fungal elicitor to enhance the production of defense compounds in plants. With the addition of a fungal elicitor (derived from Aspergillus niger), the maximum accumulation of total flavonoids (16.12 mg g(-1)) and glycyrrhetinic acid (0.18 mg g(-1)) occurred at a dose of 400 mg L(-1) of Aspergillus niger resulting in a 3.47-fold and 1.8-fold increase over control roots. However, the highest concentration of polysaccharide (106.06 mg g(-1)) was achieved with a mixture of elicitors (Aspergillus niger and salicylic acid) added to the medium, resulting in a 1.09-fold increase over Aspergillus niger treatment alone. Electrospray ionization tandem mass spectrometry (ESI-MS(n)) analysis was performed, showing that seven compounds were present after treatment with the elicitors, including uralsaponin B, licorice saponin B2, liquiritin, and (3R)-vestitol, only identified in the mixed elicitor treatment group. It has also been found that elicitors (Aspergillus niger and salicylic acid) significantly upregulated the expression of the cinnamate 4-hydroxylase (C4H), β-amyrin synthase (β-AS), squalene epoxidase (SE) and a cytochrome P450 monooxygenase (CYP72A154) genes, which are involved in the biosynthesis of bioactive compounds, and increased superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity. PMID:26490378

  13. Fractionation of Aspergillus niger cellulases by combined ion exchange affinity chromatography

    SciTech Connect

    Boyer, R.F.; Allen, T.L.; Dykema, P.A.

    1987-02-05

    Eight chemically modified cellulose supports were tested for their ability to adsorb components of the Aspergillus niger cellulase system. At least two of the most effective adsorbents, aminoethyl cellulose and carboxymethyl cellulose, were shown to be useful for the fractionation of cellulases. These supports apparently owe their resolving capacity to both ion exchange and biospecific binding effects; however, the relative importance of each effect is unknown. These observations form the basis for a new cellulase fractionation technique, combined ion exchange-affinity chromatography. 22 references.

  14. Reduced by-product formation and modified oxygen availability improve itaconic acid production in Aspergillus niger.

    PubMed

    Li, An; Pfelzer, Nina; Zuijderwijk, Robbert; Brickwedde, Anja; van Zeijl, Cora; Punt, Peter

    2013-05-01

    Aspergillus niger has an extraordinary potential to produce organic acids as proven by its application in industrial citric acid production. Previously, it was shown that expression of the cis-aconitate decarboxylase gene (cadA) from Aspergillus terreus converted A. niger into an itaconic acid producer (Li et al., Fungal Genet Bio 48: 602-611, 2011). After some initial steps in production optimization in the previous research (Li et al., BMC biotechnol 12: 57, 2012), this research aims at modifying host strains and fermentation conditions to further improve itaconic acid production. Expression of two previously identified A. terreus genes encoding putative organic acid transporters (mttA, mfsA) increased itaconic acid production in an A. niger cis-aconitate decarboxylase expressing strain. Surprisingly, the production did not increase further when both transporters were expressed together. Meanwhile, oxalic acid was accumulated as a by-product in the culture of mfsA transformants. In order to further increase itaconic acid production and eliminate by-product formation, the non-acidifying strain D15#26 and the oxaloacetate acetylhydrolase (oahA) deletion strain AB 1.13 ?oahA #76 have been analyzed for itaconic acid production. Whereas cadA expression in AB 1.13 ?oahA #76 resulted in higher itaconic acid production than strain CAD 10.1, this was not the case in strain D15#26. As expected, oxalic acid production was eliminated in both strains. In a further attempt to increase itaconic acid levels, an improved basal citric acid-producing strain, N201, was used for cadA expression. A selected transformant (N201CAD) produced more itaconic acid than strain CAD 10.1, derived from A. niger strain AB1.13. Subsequently, we have focused on the influence of dissolved oxygen (D.O.) on itaconic acid production. Interestingly, reduced D.O. levels (10-25 %) increased itaconic acid production using strain N201 CAD. Similar results were obtained in strain AB 1.13 CAD + HBD2.5 (HBD 2.5) which overexpressed a fungal hemoglobin domain. Our results showed that overexpression of the hemoglobin domain increased itaconic acid production in A. niger at lower D.O. levels. Evidently, the lower levels of D.O. have a positive influence on itaconic acid production in A. niger strains. PMID:23397482

  15. Identification and Structural Analysis of Amino Acid Substitutions that Increase the Stability and Activity of Aspergillus niger Glucose Oxidase

    PubMed Central

    Marín-Navarro, Julia; Roupain, Nicole; Talens-Perales, David; Polaina, Julio

    2015-01-01

    Glucose oxidase is one of the most conspicuous commercial enzymes due to its many different applications in diverse industries such as food, chemical, energy and textile. Among these applications, the most remarkable is the manufacture of glucose biosensors and in particular sensor strips used to measure glucose levels in serum. The generation of ameliorated versions of glucose oxidase is therefore a significant biotechnological objective. We have used a strategy that combined random and rational approaches to isolate uncharacterized mutations of Aspergillus niger glucose oxidase with improved properties. As a result, we have identified two changes that increase significantly the enzyme's thermal stability. One (T554M) generates a sulfur-pi interaction and the other (Q90R/Y509E) introduces a new salt bridge near the interphase of the dimeric protein structure. An additional double substitution (Q124R/L569E) has no significant effect on stability but causes a twofold increase of the enzyme's specific activity. Our results disclose structural motifs of the protein which are critical for its stability. The combination of mutations in the Q90R/Y509E/T554M triple mutant yielded a version of A. niger glucose oxidase with higher stability than those previously described. PMID:26642312

  16. Comparative genomics of citric-acid producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    SciTech Connect

    Grigoriev, Igor V.; Baker, Scott E.; Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; Vondervoot, Peter J.I. van de; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristen F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; Dijck, Piet W.M. van; Hofmann, Gerald; Lasure, Linda L.; Magnusson, Jon K.; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; Ooyen, Albert J.J. van; Panther, Kathyrn S.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hen; Tsang, Adrian; Brink, Johannes M. van den; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Kubicek, Christian P.; Martinez, Diego; Peij, Noel N.M.E. van; Roubos, Johannes A.; Nielsen, Jens

    2011-04-28

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up-regulation of genes relevant to glucoamylase A production, such as tRNA-synthases and protein transporters. Our results and datasets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi.[Supplemental materials (10 figures, three text documents and 16 tables) have been made available. The whole genome sequence for A. niger ATCC 1015 is available from NBCI under acc. no ACJE00000000. The up-dated sequence for A. niger CBS 513.88 is available from EMBL under acc. no AM269948-AM270415. The sequence data from the phylogeny study has been submitted to NCBI (GU296686-296739). Microarray data from this study is submitted to GEO as series GSE10983. Accession for reviewers is possible through: http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi token GSE10983] The dsmM_ANIGERa_coll511030F library and platform information is deposited at GEO under number GPL6758

  17. Evolutionary Origins of the Fumonisin Secondary Metabolite Gene Cluster in Fusarium verticillioides and Aspergillus niger

    PubMed Central

    Khaldi, Nora; Wolfe, Kenneth H.

    2011-01-01

    The secondary metabolite gene clusters of euascomycete fungi are among the largest known clusters of functionally related genes in eukaryotes. Most of these clusters are species specific or genus specific, and little is known about how they are formed during evolution. We used a comparative genomics approach to study the evolutionary origins of a secondary metabolite cluster that synthesizes a polyketide derivative, namely, the fumonisin (FUM) cluster of Fusarium verticillioides, and that of Aspergillus niger another fumonisin (fumonisin B) producing species. We identified homologs in other euascomycetes of the Fusarium verticillioides FUM genes and their flanking genes. We discuss four models for the origin of the FUM cluster in Fusarium verticillioides and argue that two of these are plausible: (i) assembly by relocation of initially scattered genes in a recent Fusarium verticillioides; or (ii) horizontal transfer of the FUM cluster from a distantly related Sordariomycete species. We also propose that the FUM cluster was horizontally transferred into Aspergillus niger, most probably from a Sordariomycete species. PMID:21716743

  18. Dual transcriptional profiling of a bacterial/fungal confrontation: Collimonas fungivorans versus Aspergillus niger.

    PubMed

    Mela, Francesca; Fritsche, Kathrin; de Boer, Wietse; van Veen, Johannes A; de Graaff, Leo H; van den Berg, Marlies; Leveau, Johan H J

    2011-09-01

    Interactions between bacteria and fungi cover a wide range of incentives, mechanisms and outcomes. The genus Collimonas consists of soil bacteria that are known for their antifungal activity and ability to grow at the expense of living fungi. In non-contact confrontation assays with the fungus Aspergillus niger, Collimonas fungivorans showed accumulation of biomass concomitant with inhibition of hyphal spread. Through microarray analysis of bacterial and fungal mRNA from the confrontation arena, we gained new insights into the mechanisms underlying the fungistatic effect and mycophagous phenotype of collimonads. Collimonas responded to the fungus by activating genes for the utilization of fungal-derived compounds and for production of a putative antifungal compound. In A. niger, differentially expressed genes included those involved in lipid and cell wall metabolism and cell defense, which correlated well with the hyphal deformations that were observed microscopically. Transcriptional profiles revealed distress in both partners: downregulation of ribosomal proteins and upregulation of mobile genetic elements in the bacteria and expression of endoplasmic reticulum stress and conidia-related genes in the fungus. Both partners experienced nitrogen shortage in each other's presence. Overall, our results indicate that the Collimonas/Aspergillus interaction is a complex interplay between trophism, antibiosis and competition for nutrients. PMID:21614084

  19. Effect of oxygen transfer rate on the composition of the pectolytic enzyme complex of Aspergillus niger

    SciTech Connect

    Zetelaki-Horvath, K.; Vas, K.

    1981-01-01

    Optimal agitation and aeration conditions (assuring O/sub 2/ transfer rates (OTR) of 12-179 mmol/L-h) were determined for pectin lyase (PL) synthesis of an Aspergillus niger strain. Components of the pectolytic enzyme complex were also investigated in order to determine whether their O/sub 2/ demand is identical with or different from that of pectin lyase. Should the latter be the case, a possibility would be given to produce enzyme complexes of different agitation and aeration conditions. The mycelium yield of Aspergillus niger was maximum at an OTR of 100 mmol/L-h. The yields of the various pectolytic enzymes reached maximum at different OTRs. PL production was highest (0.555 mumol/min-mL) at an OTR of 60 mmol/L-h. Endopolygalacturonase (PG) production has a maximum at OTR 49 mmol/L-h, with a 2nd peak at 100-135 mmol O2/L-h. Pectin esterase (PE) synthesis showed a maximum at an OTR of 12-14 mmol/L-h, while both apple juice clarifying and macerating activities gave 2 maximum at 14 and 60 mmol/L-h due to the optima of PE and endo-PG. Macerating activity showed a high value at OTR optimal for PL production as well.

  20. Studies on influence of natural biowastes on cellulase production by Aspergillus niger.

    PubMed

    Kiranmayi, M Usha; Poda, Sudhakar; Vijayalakshmi, M; Krishna, P V

    2011-11-01

    The objective of this study was to determine the influence of natural biowaste substrates such as banana peel powder and coir powder at varying environmental parameters of pH (4-9) and temperature (20-50 degrees C) on the cellulase enzyme production by Aspergillus niger. The cellulase enzyme production was analyzed by measuring the amount of glucose liberated in IU ml(-1) by using the dinitrosalicylic acid assay method. The substrates were pretreated with 1% NaOH (alkaline treatment) and autoclaved. The maximum activity of the enzyme was assayed at varying pH with temperatures being constant and varying temperatures with pH being constant. The highest activity of the enzyme at varying pH was recorded at pH 6 for banana peel powder (0.068 +/- 0.002 IU ml) and coir powder (0.049 +/- 0.002 IU ml(-1)) and the maximum activity of the enzyme at varying temperature was recorded at 35 degrees C for both banana peel powder (0.072 +/- 0.001 IU ml(-1)) and coir powder (0.046 +/- 0.003 IU ml(-1)). At varying temperatures and pH the high level of enzyme production was obtained at 35 degrees C and pH 6 by using both the substrates, respectively. However among the two substrates used for the production of cellulases by Aspergillus niger banana peel powder showed maximum enzymatic activity than coir powder as substrate. PMID:22471203

  1. Comparative genomics of citric-acid producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    SciTech Connect

    Andersen, Mikael R.; Salazar, Margarita; Schaap, Peter; van de Vondervoort, Peter; Culley, David E.; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy; Braus, Gerhard; Braus-Stromeyer, Susanna A.; Corrochano, Luis; Dai, Ziyu; van Dijck, Piet; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert; Pel, Herman J.; Poulsen, Lars; Samson, Rob; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; ATkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Noel; Roubos, Johannes A.; Nielsen, Jens B.; Baker, Scott E.

    2011-06-01

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases and protein transporters.

  2. Comparative genomics of citric-acid-producing Aspergillus niger ATCC 1015 versus enzyme-producing CBS 513.88

    PubMed Central

    Andersen, Mikael R.; Salazar, Margarita P.; Schaap, Peter J.; van de Vondervoort, Peter J.I.; Culley, David; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy M.; Braus, Gerhard H.; Braus-Stromeyer, Susanna A.; Corrochano, Luis M.; Dai, Ziyu; van Dijck, Piet W.M.; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan L.; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert J.J.; Pel, Herman J.; Poulsen, Lars; Samson, Rob A.; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; Atkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Nol N.M.E.; Roubos, Johannes A.; Nielsen, Jens; Baker, Scott E.

    2011-01-01

    The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compel additional exploration. We therefore undertook whole-genome sequencing of the acidogenic A. niger wild-type strain (ATCC 1015) and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence, and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was used to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 Mb of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis supported up-regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases, and protein transporters in the protein producing CBS 513.88 strain. Our results and data sets from this integrative systems biology analysis resulted in a snapshot of fungal evolution and will support further optimization of cell factories based on filamentous fungi. PMID:21543515

  3. Genome mining and functional genomics for siderophore production in Aspergillus niger.

    PubMed

    Franken, Angelique C W; Lechner, Beatrix E; Werner, Ernst R; Haas, Hubertus; Lokman, B Christien; Ram, Arthur F J; van den Hondel, Cees A M J J; de Weert, Sandra; Punt, Peter J

    2014-11-01

    Iron is an essential metal for many organisms, but the biologically relevant form of iron is scarce because of rapid oxidation resulting in low solubility. Simultaneously, excessive accumulation of iron is toxic. Consequently, iron uptake is a highly controlled process. In most fungal species, siderophores play a central role in iron handling. Siderophores are small iron-specific chelators that can be secreted to scavenge environmental iron or bind intracellular iron with high affinity. A second high-affinity iron uptake mechanism is reductive iron assimilation (RIA). As shown in Aspergillus fumigatus and Aspergillus nidulans, synthesis of siderophores in Aspergilli is predominantly under control of the transcription factors SreA and HapX, which are connected by a negative transcriptional feedback loop. Abolishing this fine-tuned regulation corroborates iron homeostasis, including heme biosynthesis, which could be biotechnologically of interest, e.g. the heterologous production of heme-dependent peroxidases. Aspergillus niger genome inspection identified orthologues of several genes relevant for RIA and siderophore metabolism, as well as sreA and hapX. Interestingly, genes related to synthesis of the common fungal extracellular siderophore triacetylfusarinine C were absent. Reverse-phase high-performance liquid chromatography (HPLC) confirmed the absence of triacetylfusarinine C, and demonstrated that the major secreted siderophores of A. niger are coprogen B and ferrichrome, which is also the dominant intracellular siderophore. In A. niger wild type grown under iron-replete conditions, the expression of genes involved in coprogen biosynthesis and RIA was low in the exponential growth phase but significantly induced during ascospore germination. Deletion of sreA in A. niger resulted in elevated iron uptake and increased cellular ferrichrome accumulation. Increased sensitivity toward phleomycin and high iron concentration reflected the toxic effects of excessive iron uptake. Moreover, SreA-deficiency resulted in increased accumulation of heme intermediates, but no significant increase in heme content. Together with the upregulation of several heme biosynthesis genes, these results reveal a complex heme regulatory mechanism. PMID:25062661

  4. Two Novel, Putatively Cell Wall-Associated and Glycosylphosphatidylinositol-Anchored ?-Glucanotransferase Enzymes of Aspergillus niger?

    PubMed Central

    van der Kaaij, R. M.; Yuan, X.-L.; Franken, A.; Ram, A. F. J.; Punt, P. J.; van der Maarel, M. J. E. C.; Dijkhuizen, L.

    2007-01-01

    In the genome sequence of Aspergillus niger CBS 513.88, three genes were identified with high similarity to fungal ?-amylases. The protein sequences derived from these genes were different in two ways from all described fungal ?-amylases: they were predicted to be glycosylphosphatidylinositol anchored, and some highly conserved amino acids of enzymes in the ?-amylase family were absent. We expressed two of these enzymes in a suitable A. niger strain and characterized the purified proteins. Both enzymes showed transglycosylation activity on donor substrates with ?-(1,4)-glycosidic bonds and at least five anhydroglucose units. The enzymes, designated AgtA and AgtB, produced new ?-(1,4)-glycosidic bonds and therefore belong to the group of the 4-?-glucanotransferases (EC 2.4.1.25). Their reaction products reached a degree of polymerization of at least 30. Maltose and larger maltooligosaccharides were the most efficient acceptor substrates, although AgtA also used small nigerooligosaccharides containing ?-(1,3)-glycosidic bonds as acceptor substrate. An agtA knockout of A. niger showed an increased susceptibility towards the cell wall-disrupting compound calcofluor white, indicating a cell wall integrity defect in this strain. Homologues of AgtA and AgtB are present in other fungal species with ?-glucans in their cell walls, but not in yeast species lacking cell wall ?-glucan. Possible roles for these enzymes in the synthesis and/or maintenance of the fungal cell wall are discussed. PMID:17496125

  5. Efficacy and possible mechanisms of perillaldehyde in control of Aspergillus niger causing grape decay.

    PubMed

    Tian, Jun; Wang, Yanzhen; Zeng, Hong; Li, Zongyun; Zhang, Peng; Tessema, Akalate; Peng, Xue

    2015-06-01

    A variety of plant products have been recognized for their antifungal activity and recently have attracted food industry attention for their efficacy in controlling postharvest fungal decay of fruits. The antifungal activity of perillaldehyde (PAE) was evaluated against Aspergillus niger, a known cause of grape spoilage, and possible mechanisms were explored. PAE showed notable antifungal activity against A. niger, with a minimum inhibitory concentration (MIC) and a minimum fungicidal concentration (MFC) of 0.25 and 1 ?l/ml, respectively. The accumulation of mycelial biomass was also inhibited by PAE in a dose-dependent manner, completely inhibiting mycelial growth at 1 ?l/ml. In vivo data confirmed that the vapour treatment of grapes with various concentrations of PAE markedly improved control of A. niger and suppressed natural decay. Concentrations of PAE of 0.075 ?l/ml air showed the greatest inhibition of fungal growth compared to the controls. Further experiments indicated that PAE activated a membrane-active mechanism that inhibits ergosterol synthesis, increases membrane permeability (as evidenced by extracellular pH and conductivity measurements), and disrupts membrane integrity, leading to cell death. Our findings suggest that this membrane-active mechanism makes PAE a promising potential antifungal agent for postharvest control of grape spoilage. PMID:25755082

  6. Organic acid production by Aspergillus niger in recycling culture analyzed by capillary electrophoresis.

    PubMed

    Schrickx, J M; Raedts, M J; Stouthamer, A H; van Verseveld, H W

    1995-10-10

    Wild-type Aspergillus niger N402 and glucoamylase++ overproducing transformant A. niger N402[pAB6-10]B1 have grown in maltodextrin- and xylose-limited recycling culture at pH 4.5 on mineral medium. The only products formed were organic acids and proteins, among which glucoamylase. The production of organic acids by the fungus has been analyzed qualitatively and quantitatively using capillary electrophoresis. The only organic acids produced in these cultures were substantial amounts of citric acid. This is the first demonstration of abundant oxalic acid production and a very low citric acid production by submerged cultures of A. niger. In the maltodextrin-limited culture the oxalic acid production rate increased during the first 80 h of cultivation and decreased after that time. In xylose-limited recycling culture the oxalic acid production rate always increased in time and highest values were found in the last samples taken from the culture after about 140 h of cultivation. Oxalic acid production rates were highest by the wild-type strain grown on xylose as carbon source, i.e., when the lowest glucoamylase production rates were observed. A clear negative correlation was found between the oxalic acid production rate and the respiration quotient (RQ). An increase in the oxygen consumption rate, due to the production of strongly oxidized oxalic acid, caused the RQ to be lowest at those stages of recycling cultivation when highest oxalic acid production rates were observed. PMID:8678298

  7. Metabolic model integration of the bibliome, genome, metabolome and reactome of Aspergillus niger

    PubMed Central

    Andersen, Mikael Rørdam; Nielsen, Michael Lynge; Nielsen, Jens

    2008-01-01

    The release of the genome sequences of two strains of Aspergillus niger has allowed systems-level investigations of this important microbial cell factory. To this end, tools for doing data integration of multi-ome data are necessary, and especially interesting in the context of metabolism. On the basis of an A. niger bibliome survey, we present the largest model reconstruction of a metabolic network reported for a fungal species. The reconstructed gapless metabolic network is based on the reportings of 371 articles and comprises 1190 biochemically unique reactions and 871 ORFs. Inclusion of isoenzymes increases the total number of reactions to 2240. A graphical map of the metabolic network is presented. All levels of the reconstruction process were based on manual curation. From the reconstructed metabolic network, a mathematical model was constructed and validated with data on yields, fluxes and transcription. The presented metabolic network and map are useful tools for examining systemwide data in a metabolic context. Results from the validated model show a great potential for expanding the use of A. niger as a high-yield production platform. PMID:18364712

  8. Deletion of a Chitin Synthase Gene in a Citric Acid Producing Strain of Aspergillus niger

    SciTech Connect

    Rinker, Torri E.; Baker, Scott E.

    2007-01-29

    Citric acid production by the filamentous fungus Aspergillus niger is carried out in a process that causes the organism to drastically alter its morphology. This altered morphology includes hyphal swelling and highly limited polar growth resulting in clumps of swollen cells that eventually aggregate into pellets of approximately 100 microns in diameter. In this pelleted form, A. niger has increased citric acid production as compared to growth in filamentous form. Chitin is a crucial component of the cell wall of filamentous fungi. Alterations in the deposition or production of chitin may have profound effects on the morphology of the organism. In order to study the role of chitin synthesis in pellet formation we have deleted a chitin synthase gene (csmA) in Aspergillus niger strain ATCC 11414 using a PCR based deletion construct. This class of chitin synthases is only found in filamentous fungi and is not present in yeasts. The csmA genes contain a myosin motor domain at the N-terminus and a chitin synthesis domain at the C-terminus. They are believed to contribute to the specialized polar growth observed in filamentous fungi that is lacking in yeasts. The csmA deletion strain (csmAΔ) was subjected to minimal media with and without osmotic stabilizers as well as tested in citric acid production media. Without osmotic stabilizers, the mutant germlings were abnormally swollen, primarily in the subapical regions, and contained large vacuoles. However, this swelling is ultimately not inhibitory to growth as the germlings are able to recover and undergo polar growth. Colony formation was largely unaffected in the absence of osmotic stabilizers. In citric acid production media csmAΔ was observed to have a 2.5 fold increase in citric acid production. The controlled expression of this class of chitin synthases may be useful for improving production of organic acids in filamentous fungi.

  9. Radiosensitization of Aspergillus niger and Penicillium chrysogenum using basil essential oil and ionizing radiation for food decontamination.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Minimum Inhibitory Concentration (MIC) of basil oil, was determined for two pathogenic fungi of rice, Aspergillus niger and Penicillium chrysogenum. The antifungal activity of the basil oil in combination with ionising radiation was then investigated to determine if basil oil caused radiosensit...

  10. A chemical epigenetics approach for engineering the in situ biosynthesis of a cryptic natural product from Aspergillus niger.

    PubMed

    Henrikson, Jon C; Hoover, Ashley R; Joyner, P Matthew; Cichewicz, Robert H

    2009-02-01

    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. PMID:19156306

  11. Comparison of different inoculating methods to evaluate the pathogenicity and virulence of Aspergillus niger on two maize hybrids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year field study was conducted to determine the effects of inoculation techniques on the aggressiveness of Aspergillus niger kernel infection in A. flavus resistant and susceptible maize hybrids. Ears were inoculated with the silk-channel, side-needle, and spray techniques 7 days after midsilk...

  12. Presence of epoxide hydrolase activity in Aspergillus niger: Hydrolysis of 6', 7'-epoxybergamottin to 6', 7'-dihydroxybergamottin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 6', 7'-epoxybergamottin (EB) is one of major furanocoumarins in grapefruit. Previously, we have shown that Aspergillus niger has a capability of metabolizing EB into 6', 7'-dihydroxybergamottin (DHB), which is further metabolized to bergaptol and bergaptol-5-sulfate in vivo. In this study, we at...

  13. Culture supernatants of patient-derived Aspergillus isolates have toxic and lytic activity towards neurons and glial cells.

    PubMed

    Speth, C; Rambach, G; Lass-Flrl, C; Wrzner, R; Gasque, P; Mohsenipour, I; Dierich, M P

    2000-12-01

    Infection of the central nervous system by the ubiquitous fungi Aspergillus spp. is a life-threatening disease. Therefore we investigated the mechanism of brain damage by fungal infection. To examine whether secretory factors of Aspergillus isolates derived from patients can induce death of different brain cells, culture supernatants of Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus and Aspergillus niger were added to different astrocytes as well as to the neuroblastoma cell line SK-N-SH, and to the microglial cell line CHME. All four fungal species were shown to secrete toxic factors with neurons being most sensitive against these factors. Very low amounts and short incubation times are sufficient to induce irreversible cell damage, indicating that secreted factors might also affect distant brain regions. Further characterization of the toxic factors revealed that A. fumigatus and A. terreus produced small, heat-stable components whereas the toxic activity of A. niger filtrates was triggered by a high molecular mass factor which could be inactivated by heat. The active component of A. flavus had a molecular mass similar to that of A. niger but was heat-stable and had a significantly lower activity. Taken together these results indicate that secretion of different necrotizing factors might contribute to brain lesions in patients with cerebral aspergillosis. PMID:11118912

  14. Improved mannan-degrading enzymes' production by Aspergillus niger through medium optimization.

    PubMed

    Mohamad, Siti Norita; Ramanan, Ramakrishnan Nagasundara; Mohamad, Rosfarizan; Ariff, Arbakariya B

    2011-02-28

    The effect of different carbon and nitrogen sources on the production of mannan-degrading enzymes, focussing on β-mannanase, by Aspergillus niger was investigated using shake flask culture. The β-mannanase activity obtained during growth of A. niger on guar gum (GG, 1495 nkat mL(-1)) was much higher than those observed on other carbon substrates, locust bean gum (1148 nkat mL(-1)), α-cellulose (10.7 nkat mL(-1)), glucose (8.8 nkat mL(-1)) and carboxymethylcellulose (4.6 nkat mL(-1)). For fermentation using GG as a carbon source, bacteriological peptone gave the highest β-mannanase activity (1744 nkat mL(-1)) followed by peptone from meat (1168 nkat mL(-1)), yeast extract (817 nkat mL(-1)), ammonium sulphate (241 nkat mL(-1)), ammonium nitrate (113 nkat mL(-1)) and ammonium chloride (99 nkat mL(-1)) when used as a nitrogen source. The composition of bacteriological peptone and initial pH of the medium were further optimized using response surface methodology (RSM). Medium consisted of 21.3 g L(-1) GG and 57 g L(-1) peptone with initial culture pH of 5.5 was optimum for β-mannanase production (2063 nkat mL(-1)) by A. niger. The β-mannanase production obtained in this study using A. niger was significantly higher than those reported in the literature. PMID:20970530

  15. An artificially constructed Syngonium podophyllum-Aspergillus niger combinate system for removal of uranium from wastewater.

    PubMed

    He, Jia-Dong; Wang, Yong-Dong; Hu, Nan; Ding, Dexin; Sun, Jing; Deng, Qin-Wen; Li, Chang-Wu; Xu, Fei

    2015-12-01

    Aspergillus niger was inoculated to the roots of five plants, and the Syngonium podophyllum-A. niger combinate system (SPANCS) was found to be the most effective in removing uranium from hydroponic liquid with initial uranium concentration of 5 mg L(-1). Furthermore, the hydroponic experiments on the removal of uranium from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) by the SPANCS were conducted, the inhibitory effect of A. niger on the growth of S. podophyllum in the SPANCS was studied, the accumulation characteristics of uranium by S. podophyllum in the SPANCS were analyzed, and the Fourier transform infrared (FT-IR) and extended X-ray absorption fine structure (EXAFS) spectra were measured. The results show that the removal of uranium by the SPANCS from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) reached 98.20, 97.90, and 98.50 %, respectively, after 37 days of accumulation of uranium; that the uranium concentrations in the hydroponic liquids decreased to 0.009, 0.021, and 0.045 mg L(-1), respectively, which are lower than the stipulated concentration for discharge of 0.050 mg L(-1) by the People's Republic of China; that A. niger helped to generate more groups in the root of S. podophyllum which can improve the complexing capability of S. podophyllum for uranium; and that the uranium accumulated in the root of S. podophyllum was in the form of phosphate uranyl and carboxylic uranyl. PMID:26208659

  16. Cytosolic streaming in vegetative mycelium and aerial structures of Aspergillus niger

    PubMed Central

    Bleichrodt, R.; Vinck, A.; Krijgsheld, P.; van Leeuwen, M.R.; Dijksterhuis, J.; Wsten, H.A.B.

    2013-01-01

    Aspergillus niger forms aerial hyphae and conidiophores after a period of vegetative growth. The hyphae within the mycelium of A. niger are divided by septa. The central pore in these septa allows for cytoplasmic streaming. Here, we studied inter- and intra-compartmental streaming of the reporter protein GFP in A. niger. Expression of the gene encoding nuclear targeted GFP from the gpdA or glaA promoter resulted in strong fluorescence of nuclei within the vegetative hyphae and weak fluorescence in nuclei within the aerial structures. These data and nuclear run on experiments showed that gpdA and glaA are higher expressed in the vegetative mycelium when compared to aerial hyphae, conidiophores and conidia. Notably, gpdA or glaA driven expression of the gene encoding cytosolic GFP resulted in strongly fluorescent vegetative hyphae and aerial structures. Apparently, GFP streams from vegetative hyphae into aerial structures. This was confirmed by monitoring fluorescence of photo-activatable GFP (PA-GFP). In contrast, PA-GFP did not stream from aerial structures to vegetative hyphae. Streaming of PA-GFP within vegetative hyphae or within aerial structures of A. niger occurred at a rate of 1015 ?m s-1. Taken together, these results not only show that GFP streams from the vegetative mycelium to aerial structures but it also indicates that its encoding RNA is not streaming. Absence of RNA streaming would explain why distinct RNA profiles were found in aerial structures and the vegetative mycelium by nuclear run on analysis and micro-array analysis. PMID:23450745

  17. Cytosolic streaming in vegetative mycelium and aerial structures of Aspergillus niger.

    PubMed

    Bleichrodt, R; Vinck, A; Krijgsheld, P; van Leeuwen, M R; Dijksterhuis, J; Wsten, H A B

    2013-03-15

    Aspergillus niger forms aerial hyphae and conidiophores after a period of vegetative growth. The hyphae within the mycelium of A. niger are divided by septa. The central pore in these septa allows for cytoplasmic streaming. Here, we studied inter- and intra-compartmental streaming of the reporter protein GFP in A. niger. Expression of the gene encoding nuclear targeted GFP from the gpdA or glaA promoter resulted in strong fluorescence of nuclei within the vegetative hyphae and weak fluorescence in nuclei within the aerial structures. These data and nuclear run on experiments showed that gpdA and glaA are higher expressed in the vegetative mycelium when compared to aerial hyphae, conidiophores and conidia. Notably, gpdA or glaA driven expression of the gene encoding cytosolic GFP resulted in strongly fluorescent vegetative hyphae and aerial structures. Apparently, GFP streams from vegetative hyphae into aerial structures. This was confirmed by monitoring fluorescence of photo-activatable GFP (PA-GFP). In contrast, PA-GFP did not stream from aerial structures to vegetative hyphae. Streaming of PA-GFP within vegetative hyphae or within aerial structures of A. niger occurred at a rate of 10-15 ?m s(-1). Taken together, these results not only show that GFP streams from the vegetative mycelium to aerial structures but it also indicates that its encoding RNA is not streaming. Absence of RNA streaming would explain why distinct RNA profiles were found in aerial structures and the vegetative mycelium by nuclear run on analysis and micro-array analysis. PMID:23450745

  18. Production and Optimization of Cellulase Enzyme Using Aspergillus niger USM AI 1 and Comparison with Trichoderma reesei via Solid State Fermentation System

    PubMed Central

    Lee, C. K.; Darah, I.; Ibrahim, C. O.

    2011-01-01

    Novel design solid state bioreactor, FERMSOSTAT, had been evaluated in cellulase production studies using local isolate Aspergillus niger USM AI 1 grown on sugarcane bagasse and palm kernel cake at 1?:?1 (w/w) ratio. Under optimised SSF conditions of 0.5?kg substrate; 70% (w/w) moisture content; 30C; aeration at 4?L/h g fermented substrate for 5?min and mixing at 0.5?rpm for 5?min, about 3.4?U/g of Filter paper activity (FPase) was obtained. At the same time, comparative studies of the enzymes production under the same SSF conditions indicated that FPase produced by A. niger USM AI 1 was about 35.3% higher compared to Trichoderma reesei. This shows that the performance of this newly designed SSF bioreactor is acceptable and potentially used as prototype for larger-scale bioreactor design. PMID:21350665

  19. Isolation and identification of Aspergillus spp. from brown kiwi (Apteryx mantelli) nocturnal houses in New Zealand.

    PubMed

    Glare, Travis R; Gartrell, Brett D; Brookes, Jenny J; Perrott, John K

    2014-03-01

    Aspergillosis, a disease caused by infection with Aspergillus spp., is a common cause of death in birds globally and is an irregular cause of mortality of captive kiwi (Apteryx spp.). Aspergillus spp. are often present in rotting plant material, including the litter and nesting material used for kiwi in captivity. The aim of this study was to survey nocturnal kiwi houses in New Zealand to assess the levels of Aspergillus currently present in leaf litter. Samples were received from 11 nocturnal kiwi houses from throughout New Zealand, with one site supplying multiple samples over time. Aspergillus was isolated and quantified by colony counts from litter samples using selective media and incubation temperatures. Isolates were identified to the species level by amplification and sequencing of ITS regions of the ribosomal. Aspergillus spp. were recovered from almost every sample; however, the levels in most kiwi houses were below 1000 colony-forming units (CFU)/g of wet material. The predominant species was Aspergillus fumigatus, with rare occurrences of Aspergillus niger, Aspergillus nidulans, and Aspergillus parasiticus. Only one site had no detectable Aspergillus. The limit of detection was around 50 CFU/g wet material. One site was repeatedly sampled as it had a high loading of A. fumigatus at the start of the survey and had two recent clinical cases of aspergillosis diagnosed in resident kiwi. Environmental loading at this site with Aspergillus spp. reduced but was not eliminated despite changes of the litter. The key finding of our study is that the background levels of Aspergillus spores in kiwi nocturnal houses in New Zealand are low, but occasional exceptions occur and are associated with the onset of aspergillosis in otherwise healthy birds. The predominant Aspergillus species present in the leaf litter was A. fumigatus, but other species were also present. Further research is needed to confirm the optimal management of leaf litter to minimize Aspergillus spore counts. However, in the interim, our recommendations are that leaf litter should be freshly collected from areas of undisturbed forest areas and spread immediately after collection, without interim storage. PMID:24758108

  20. Oxalic acid production by citric acid-producing Aspergillus niger overexpressing the oxaloacetate hydrolase gene oahA.

    PubMed

    Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro

    2014-05-01

    The filamentous fungus Aspergillus niger is used worldwide in the industrial production of citric acid. However, under specific cultivation conditions, citric acid-producing strains of A. niger accumulate oxalic acid as a by-product. Oxalic acid is used as a chelator, detergent, or tanning agent. Here, we sought to develop oxalic acid hyperproducers using A. niger as a host. To generate oxalic acid hyperproducers by metabolic engineering, transformants overexpressing the oahA gene, encoding oxaloacetate hydrolase (OAH; EC 3.7.1.1), were constructed in citric acid-producing A. niger WU-2223L as a host. The oxalic acid production capacity of this strain was examined by cultivation of EOAH-1 under conditions appropriate for oxalic acid production with 30 g/l glucose as a carbon source. Under all the cultivation conditions tested, the amount of oxalic acid produced by EOAH-1, a representative oahA-overexpressing transformant, exceeded that produced by A. niger WU-2223L. A. niger WU-2223L and EOAH-1 produced 15.6 and 28.9 g/l oxalic acid, respectively, during the 12-day cultivation period. The yield of oxalic acid for EOAH-1 was 64.2 % of the maximum theoretical yield. Our method for oxalic acid production gave the highest yield of any study reported to date. Therefore, we succeeded in generating oxalic acid hyperproducers by overexpressing a single gene, i.e., oahA, in citric acid-producing A. niger as a host. PMID:24615146

  1. Development of an Unmarked Gene Deletion System for the Filamentous Fungi Aspergillus niger and Talaromyces versatilis

    PubMed Central

    Delmas, Stphane; Llanos, Agustina; Parrou, Jean-Luc; Kokolski, Matthew; Pullan, Steven T.; Shunburne, Lee

    2014-01-01

    In this article, we present a method to delete genes in filamentous fungi that allows recycling of the selection marker and is efficient in a nonhomologous end-joining (NHEJ)-proficient strain. We exemplify the approach by deletion of the gene encoding the transcriptional regulator XlnR in the fungus Aspergillus niger. To show the efficiency and advantages of the method, we deleted 8 other genes and constructed a double mutant in this species. Moreover, we showed that the same principle also functions in a different genus of filamentous fungus (Talaromyces versatilis, basionym Penicillium funiculosum). This technique will increase the versatility of the toolboxes for genome manipulation of model and industrially relevant fungi. PMID:24682295

  2. Purification and characterization of a highly enantioselective epoxide hydrolase from Aspergillus niger.

    PubMed

    Morisseau, C; Archelas, A; Guitton, C; Faucher, D; Furstoss, R; Baratti, J C

    1999-07-01

    The epoxide hydrolase from Aspergillus niger was purified to homogeneity using a four-step procedure and p-nitrostyrene oxide (pNSO) as substrate. The enzyme was purified 246-fold with 4% activity yield. The protein is a tetramer composed of four identical subunits of molecular mass 45 kDa. Maximum activity was observed at 40 degrees C, pH 7.0, and with dimethylformamide as cosolvent to dissolve pNSO. Hydrolysis of pNSO was highly enantioselective, with an E value (i.e. enantiomeric ratio) of 40 and a high regioselectivity (97%) for the less hindered carbon atom of the epoxide. This enzyme may be a good biocatalyst for the preparation of enantiopure epoxides or diols. PMID:10406946

  3. Amylolysis of raw corn by Aspergillus niger for simultaneous ethanol fermentation

    SciTech Connect

    Han, I.Y.; Steinberg, M.P.

    1987-01-01

    The novelty of this approach was hydrolysis of the raw starch in ground corn to fermentable sugars that are simultaneously fermented to ethanol by yeast in a nonsterile environment. Thus, the conventional cooking step can be eliminated for energy conservation. A koji of Aspergillus niger grown on whole corn for 3 days was the crude enzyme source. A ratio of 0.2 g dry koji/g total solids was found sufficient. Optimum pH was 4.2. Ethanol concentration was 7.7% (w/w) in the aqueous phase with 92% raw starch conversion. Agitation increased rate. Sacharification was the rate-limiting step. The initial ethanol concentration preventing fermentation was estimated to be 8.3% by weight. (Refs. 96).

  4. Refinement of the crystal structures of biomimetic weddellites produced by microscopic fungus Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Rusakov, A. V.; Frank-Kamenetskaya, O. V.; Gurzhiy, V. V.; Zelenskaya, M. S.; Izatulina, A. R.; Sazanova, K. V.

    2014-05-01

    The single-crystal structures of four biomimetic weddellites CaC2O4 · (2 + x)H2O with different contents of zeolitic water ( x = 0.10-0.24 formula units) produced by the microscopic fungus Aspergillus niger were refined from X-ray diffraction data ( R = 0.029-0.038). The effect of zeolitic water content on the structural stability of weddellite was analyzed. The parameter a was shown to increase with increasing x due to the increase in the distance between water molecules along this direction. The water content and structural parameters of the synthesized weddellites are similar to those of weddellites from biofilms and kidney stones.

  5. Biotransformations of imbricatolic acid by Aspergillus niger and Rhizopus nigricans cultures.

    PubMed

    Schmeda-Hirschmann, Guillermo; Aranda, Carlos; Kurina, Marcela; Rodrguez, Jaime A; Theoduloz, Cristina

    2007-01-01

    Microbial transformation of imbricatolic acid (1) by Aspergillus niger afforded 1alpha-hydroxyimbricatolic acid (2), while transformation with Rhizopus nigricans yielded 15-hydroxy-8,17-epoxylabdan-19-oic acid (3). When the diterpene 1 was added to a Cunninghamella echinulata culture, the main products were the microbial metabolites mycophenolic acid (4) and its 3-hydroxy derivative 5. All the structures were elucidated by spectroscopic methods. The cytotoxicity of these compounds towards human lung fibroblasts and AGS cells was assessed. While 4 and 5 showed low cytotoxicity, with IC50 values > 1000 microM against AGS cells and fibroblasts, 1alpha-hydroxyimbricatolic acid (2) presented moderate toxicity towards these targets, with IC50 values of 307 and 631 microM, respectively. The structure of 2 is presented for the first time. PMID:17873843

  6. Effect of Microgravity on Fungistatic Activity of an α-Aminophosphonate Chitosan Derivative against Aspergillus niger

    PubMed Central

    Lee, Yang Soo; Kim, Byoung-Suhk

    2015-01-01

    Biocontamination within the international space station is ever increasing mainly due to human activity. Control of microorganisms such as fungi and bacteria are important to maintain the well-being of the astronauts during long-term stay in space since the immune functions of astronauts are compromised under microgravity. For the first time control of the growth of an opportunistic pathogen, Aspergillus niger, under microgravity is studied in the presence of α-aminophosphonate chitosan. A low-shear modelled microgravity was used to mimic the conditions similar to space. The results indicated that the α-aminophosphonate chitosan inhibited the fungal growth significantly under microgravity. In addition, the inhibition mechanism of the modified chitosan was studied by UV-Visible spectroscopy and cyclic voltammetry. This work highlighted the role of a bio-based chitosan derivative to act as a disinfectant in space stations to remove fungal contaminants. PMID:26468641

  7. Effect of Microgravity on Fungistatic Activity of an ?-Aminophosphonate Chitosan Derivative against Aspergillus niger.

    PubMed

    Devarayan, Kesavan; Sathishkumar, Yesupatham; Lee, Yang Soo; Kim, Byoung-Suhk

    2015-01-01

    Biocontamination within the international space station is ever increasing mainly due to human activity. Control of microorganisms such as fungi and bacteria are important to maintain the well-being of the astronauts during long-term stay in space since the immune functions of astronauts are compromised under microgravity. For the first time control of the growth of an opportunistic pathogen, Aspergillus niger, under microgravity is studied in the presence of ?-aminophosphonate chitosan. A low-shear modelled microgravity was used to mimic the conditions similar to space. The results indicated that the ?-aminophosphonate chitosan inhibited the fungal growth significantly under microgravity. In addition, the inhibition mechanism of the modified chitosan was studied by UV-Visible spectroscopy and cyclic voltammetry. This work highlighted the role of a bio-based chitosan derivative to act as a disinfectant in space stations to remove fungal contaminants. PMID:26468641

  8. An acidic pectin lyase from Aspergillus niger with favourable efficiency in fruit juice clarification.

    PubMed

    Xu, S X; Qin, X; Liu, B; Zhang, D Q; Zhang, W; Wu, K; Zhang, Y H

    2015-02-01

    The pectin lyase gene pnl-zj5a from Aspergillus niger ZJ5 was identified and expressed in Pichia pastoris. PNL-ZJ5A was purified by ultrafiltration, anion exchange and gel chromatography. The Km and Vmax values determined using citrus pectin were 0.66 mg ml(-1) and 32.6 ?mol min(-1) mg(-1) , respectively. PNL-ZJ5A exhibited optimal activity at 43C and retained activity over 25-50C. PNL-ZJ5A was optimally active at pH 5 and effective in apple juice clarification. Compared with controls, PNL-ZJ5A increased the fruit juice yield significantly. Furthermore, PNL-ZJ5A reduced the viscosity of apple juice by 38.8% and increased its transmittance by 86.3%. PNL-ZJ5A combined with a commercial pectin esterase resulted in higher juice volume. PMID:25382689

  9. Aroma enhancement in wines using co-immobilized Aspergillus niger glycosidases.

    PubMed

    Gonzlez-Pombo, Paula; Faria, Laura; Carrau, Francisco; Batista-Viera, Francisco; Brena, Beatriz M

    2014-01-15

    A major fraction of monoterpenes and norisoprenoids in young wines is conjugated to sugars representing a significant reservoir of aromatic precursors. To promote their release, ?-glucosidase, ?-arabinosidase, and ?-rhamnosidase from a commercial Aspergillus niger preparation, were immobilized onto acrylic beads. The aim of this work was the development and application of an immobilized biocatalyst, due to the well-known advantages over soluble enzyme preparations: control of the reaction progress and preparation of enzyme-free products. In addition, the obtained derivative showed increased stability in simile wine conditions. After the treatment of Muscat wine with the biocatalyst for 20days, free monoterpenes increased significantly (from 1119 to 2132?g/L, p<0.01) with respect to the control wine. Geraniol was increased 3,4-fold over its flavor thresholds, and accordingly its impact on sensorial properties was very relevant: nine of ten judges considered treated wine more intense in fruit and floral notes. PMID:24054229

  10. Shotgun Proteomics of Aspergillus niger Microsomes upon d-Xylose Induction▿ †

    PubMed Central

    de Oliveira, José Miguel P. Ferreira; van Passel, Mark W. J.; Schaap, Peter J.; de Graaff, Leo H.

    2010-01-01

    Protein secretion plays an eminent role in cell maintenance and adaptation to the extracellular environment of microorganisms. Although protein secretion is an extremely efficient process in filamentous fungi, the mechanisms underlying protein secretion have remained largely uncharacterized in these organisms. In this study, we analyzed the effects of the d-xylose induction of cellulase and hemicellulase enzyme secretion on the protein composition of secretory organelles in Aspergillus niger. We aimed to systematically identify the components involved in the secretion of these enzymes via mass spectrometry of enriched subcellular microsomal fractions. Under each condition, fractions enriched for secretory organelles were processed for tandem mass spectrometry, resulting in the identification of peptides that originate from 1,081 proteins, 254 of which—many of them hypothetical proteins—were predicted to play direct roles in the secretory pathway. d-Xylose induction led to an increase in specific small GTPases known to be associated with polarized growth, exocytosis, and endocytosis. Moreover, the endoplasmic-reticulum-associated degradation (ERAD) components Cdc48 and all 14 of the 20S proteasomal subunits were recruited to the secretory organelles. In conclusion, induction of extracellular enzymes results in specific changes in the secretory subproteome of A. niger, and the most prominent change found in this study was the recruitment of the 20S proteasomal subunits to the secretory organelles. PMID:20453123

  11. Conversion of cassava starch to biomass, carbohydrates, and acids by Aspergillus niger.

    PubMed

    Tan, K H; Ferguson, L B; Carlton, C

    1984-01-01

    The filamentous fungus, Aspergillus niger, efficiently converted cassava polysaccharides to mycelial mass, simple sugars, and acids during the course of its growth. A typical 70-ml culture broth containing 2% cassava polysaccharides yielded 0.38 g dry mycelial mass, 1.14 mmol reducing sugars, and 1.17 meq acids at the end of 42 h. About 70% of the initial total carbohydrate in the medium was degraded during the same period. The sugars and acids in the culture broths were analyzed by HPLC on a single Aminex HPX-87 column at 55 degrees C, using 0.013 N H2SO4 as the eluting solvent. Cassava polysaccharides were degraded to oligosaccharides, maltotriose, maltose, and glucose beyond the 20-h growth periods, with maltotriose emerging as the major simple sugar. The appearance of citric, malic, gluconic, succinic, and fumaric acids accounted mostly for the decreasing pH in the growth media. Formation of carbohydrate species in the culture broths was closely related to the biosynthesis and secretion of several carbohydrases by A. niger. The extracellular carbohydrases were separated and identified by chromatofocusing and polyacrylamide gel electrophoresis to be amyloglucosidase (EC 3.1.2.3), alpha-amylase (EC 3.2.1.1), and alpha-glucosidase (EC 3.2.1.20), respectively. PMID:6490584

  12. Enzymatic detergent formulation containing amylase from Aspergillus niger: a comparative study with commercial detergent formulations.

    PubMed

    Mitidieri, Sydnei; Souza Martinelli, Anne Helene; Schrank, Augusto; Vainstein, Marilene Henning

    2006-07-01

    There is a wide range of biotechnological applications for amylases, including the textile, pharmaceutical, food and laundry industries. Hydrolytic enzymes are 100% biodegradable and enzymatic detergents can achieve effective cleaning with lukewarm water. Microorganisms and culture media were tested for amylase production and the best producer was Aspergillus niger L119 (3.9 U ml(-1) +/- 0.2) in submerged culture and its amylase demonstrated excellent activity at 50-55 degrees C and pH 4.0, remaining stable at 53 degrees C for up to 200 h. In order to establish the potential uses of this enzyme in detergents, different formulations were tested using the A. niger amylase extract. Enzyme activity was compared with three commercial formulations. The detergents are used in hospitals to clean surgical and endoscopy equipment. The presence of amylase in the formulation is because of its action within hospital drainage system, whether or not it has any function in cleaning the equipment. PMID:16112858

  13. Switching from a Unicellular to Multicellular Organization in an Aspergillus niger Hypha

    PubMed Central

    Bleichrodt, Robert-Jan; Hulsman, Marc

    2015-01-01

    ABSTRACT Pores in fungal septa enable cytoplasmic streaming between hyphae and their compartments. Consequently, the mycelium can be considered unicellular. However, we show here that Woronin bodies close ~50% of the three most apical septa of growing hyphae of Aspergillus niger. The incidence of closure of the 9th and 10th septa was even ?94%. Intercompartmental streaming of photoactivatable green fluorescent protein (PA-GFP) was not observed when the septa were closed, but open septa acted as a barrier, reducing the mobility rate of PA-GFP ~500 times. This mobility rate decreased with increasing septal age and under stress conditions, likely reflecting a regulatory mechanism affecting septal pore diameter. Modeling revealed that such regulation offers effective control of compound concentration between compartments. Modeling also showed that the incidence of septal closure in A.niger had an even stronger impact on cytoplasmic continuity. Cytoplasm of hyphal compartments was shown not to be in physical contact when separated by more than 4 septa. Together, data show that apical compartments of growing hyphae behave unicellularly, while older compartments have a multicellular organization. PMID:25736883

  14. Spatial differentiation of gene expression in Aspergillus niger colony grown for sugar beet pulp utilization.

    PubMed

    Benoit, Isabelle; Zhou, Miaomiao; Vivas Duarte, Alexandra; Downes, Damien J; Todd, Richard B; Kloezen, Wendy; Post, Harm; Heck, Albert J R; Maarten Altelaar, A F; de Vries, Ronald P

    2015-01-01

    Degradation of plant biomass to fermentable sugars is of critical importance for the use of plant materials for biofuels. Filamentous fungi are ubiquitous organisms and major plant biomass degraders. Single colonies of some fungal species can colonize massive areas as large as five soccer stadia. During growth, the mycelium encounters heterogeneous carbon sources. Here we assessed whether substrate heterogeneity is a major determinant of spatial gene expression in colonies of Aspergillus niger. We analyzed whole-genome gene expression in five concentric zones of 5-day-old colonies utilizing sugar beet pulp as a complex carbon source. Growth, protein production and secretion occurred throughout the colony. Genes involved in carbon catabolism were expressed uniformly from the centre to the periphery whereas genes encoding plant biomass degrading enzymes and nitrate utilization were expressed differentially across the colony. A combined adaptive response of carbon-catabolism and enzyme production to locally available monosaccharides was observed. Finally, our results demonstrate that A. niger employs different enzymatic tools to adapt its metabolism as it colonizes complex environments. PMID:26314379

  15. Bioleaching of heavy metals from a low-grade mining ore using Aspergillus niger.

    PubMed

    Mulligan, Catherine N; Kamali, Mahtab; Gibbs, Bernard F

    2004-07-01

    The main concern of this study is to develop a feasible and economical technique to microbially recover metals from oxide low-grade ores. Owing to the significant quantities of metals that are embodied in low-grade ores and mining residues, these are potential viable sources of metals. In addition, they potentially endanger the environment, as the metals they contain may be released to the environment in hazardous form. Hence, mining industries are seeking an efficient, economic technique to handle these ores. Pyrometallurgical and hydrometallurgical techniques are either very expensive, energy intensive or have a negative impact on the environment. For these reasons, biohydrometallurgical techniques are coming into perspective. In this study, by employing Aspergillus niger, the feasibility of recovery of metals from a mining residue is shown. A. niger exhibits good potential in generating a variety of organic acids effective for metal solubilization. Organic acid effectiveness was enhanced when sulfuric acid was added to the medium. Different agricultural wastes such as potato peels were tested. In addition, different auxiliary processes were evaluated in order to either elevate the efficiency or reduce costs. Finally, maximum solubilization of 68%, 46% and 34% were achieved for copper, zinc and nickel, respectively. Also iron co-dissolution was minimized as only 7% removal occurred. PMID:15177728

  16. Invitro and invivo antifungal activity of Cassia surattensis flower against Aspergillus niger.

    PubMed

    Sumathy, Vello; Zakaria, Zuraini; Jothy, Subramanion L; Gothai, Sivapragasam; Vijayarathna, Soundararajan; Yoga Latha, Lachimanan; Chen, Yeng; Sasidharan, Sreenivasan

    2014-12-01

    Invasive aspergillosis (IA) in immunocompromised host is a major infectious disease leading to reduce the survival rate of world population. Aspergillus niger is a causative agent causing IA. Cassia surattensis plant is commonly used in rural areas to treat various types of disease. C. surattensis flower extract was evaluated against the systemic aspergillosis model in this study. Qualitative measurement of fungal burden suggested a reduction pattern in the colony forming unit (CFU) of lung, liver, spleen and kidney for the extract treated group. Galactomannan assay assessment showed a decrease of fungal load in the treatment and positive control group with galactomannan index (GMI) value of 1.27 and 0.25 on day 28 but the negative control group showed high level of galactomannan in the serum with GMI value of 3.58. Histopathology examinations of the tissues featured major architecture modifications in the tissues of negative control group. Tissue reparation and recovery from infection were detected in extract treated and positive control group. Time killing fungicidal study of A. niger revealed dependence of the concentration of C. surattensis flower extract. PMID:25457794

  17. Seeds as natural matrices for immobilization of Aspergillus niger mycelium producing pectinases.

    PubMed

    Fiedurek, J; Szczodrak, J; Rogalski, J

    1995-04-01

    A simple method for the immobilization of Aspergillus niger mycelium producing polygalacturonase (PG) and pectinesterase (PE) is described. Fungal conidia were immobilized on wheat, rye, barley, peas, buckwheat and mustards seeds. Spongy mycelia overgrowing the seed surfaces on mineral medium with pectin produced extracellular PG and PE; the highest production was reached on the wheat carrier. Some of the variables influencing the enzymatic activity have been optimized. After every 24 h, a culture liquid with 6.8-7.8 U of PG ml-1 and 7.0-10.1 U of PE ml-1 was obtained. This procedure also made possible repeated batch enzyme production and, as many as eight subsequent 24-h batches could be fermented by using the same carrier without any loss of PG activity. The addition of sodium orthovanadate (1 mmol) into the medium with pectin caused a significant increase in PG and PE activity produced by free cells of A. niger (by 1.59-fold and 1.67-fold respectively), and only 0.47-fold of PG activity in case of the immobilized mycelium. PMID:7744727

  18. Efficacy of lipase from Aspergillus niger as an additive in detergent formulations: a statistical approach.

    PubMed

    Saisubramanian, N; Edwinoliver, N G; Nandakumar, N; Kamini, N R; Puvanakrishnan, R

    2006-08-01

    The efficacy of lipase from Aspergillus niger MTCC 2594 as an additive in laundry detergent formulations was assessed using response surface methodology (RSM). A five-level four-factorial central composite design was chosen to explain the washing protocol with four critical factors, viz. detergent concentration, lipase concentration, buffer pH and washing temperature. The model suggested that all the factors chosen had a significant impact on oil removal and the optimal conditions for the removal of olive oil from cotton fabric were 1.0% detergent, 75 U of lipase, buffer pH of 9.5 and washing temperature of 25 degrees C. Under optimal conditions, the removal of olive oil from cotton fabric was 33 and 17.1% at 25 and 49 degrees C, respectively, in the presence of lipase over treatment with detergent alone. Hence, lipase from A. niger could be effectively used as an additive in detergent formulation for the removal of triglyceride soil both in cold and warm wash conditions. PMID:16491364

  19. Bacillus subtilis attachment to Aspergillus niger hyphae results in mutually altered metabolism.

    PubMed

    Benoit, Isabelle; van den Esker, Marielle H; Patyshakuliyeva, Aleksandrina; Mattern, Derek J; Blei, Felix; Zhou, Miaomiao; Dijksterhuis, Jan; Brakhage, Axel A; Kuipers, Oscar P; de Vries, Ronald P; Kovács, Ákos T

    2015-06-01

    Interaction between microbes affects the growth, metabolism and differentiation of members of the microbial community. While direct and indirect competition, like antagonism and nutrient consumption have a negative effect on the interacting members of the population, microbes have also evolved in nature not only to fight, but in some cases to adapt to or support each other, while increasing the fitness of the community. The presence of bacteria and fungi in soil results in various interactions including mutualism. Bacilli attach to the plant root and form complex communities in the rhizosphere. Bacillus subtilis, when grown in the presence of Aspergillus niger, interacts similarly with the fungus, by attaching and growing on the hyphae. Based on data obtained in a dual transcriptome experiment, we suggest that both fungi and bacteria alter their metabolism during this interaction. Interestingly, the transcription of genes related to the antifungal and putative antibacterial defence mechanism of B. subtilis and A. niger, respectively, are decreased upon attachment of bacteria to the mycelia. Analysis of the culture supernatant suggests that surfactin production by B. subtilis was reduced when the bacterium was co-cultivated with the fungus. Our experiments provide new insights into the interaction between a bacterium and a fungus. PMID:25040940

  20. Optimization of Fermentation Medium for Extracellular Lipase Production from Aspergillus niger Using Response Surface Methodology

    PubMed Central

    Jia, Jia; Yang, Xiaofeng; Wu, Zhiliang; Zhang, Qian; Lin, Zhi; Guo, Hongtao; Lin, Carol Sze Ki; Wang, Jianying; Wang, Yunshan

    2015-01-01

    Lipase produced by Aspergillus niger is widely used in various industries. In this study, extracellular lipase production from an industrial producing strain of A. niger was improved by medium optimization. The secondary carbon source, nitrogen source, and lipid were found to be the three most influential factors for lipase production by single-factor experiments. According to the statistical approach, the optimum values of three most influential parameters were determined: 10.5 g/L corn starch, 35.4 g/L soybean meal, and 10.9 g/L soybean oil. Using this optimum medium, the best lipase activity was obtained at 2,171 U/mL, which was 16.4% higher than using the initial medium. All these results confirmed the validity of the model. Furthermore, results of the Box-Behnken Design and quadratic models analysis indicated that the carbon to nitrogen (C/N) ratio significantly influenced the enzyme production, which also suggested that more attention should be paid to the C/N ratio for the optimization of enzyme production. PMID:26366414

  1. Morphology of Filamentous Fungi: Linking Cellular Biology to Process Engineering Using Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Krull, Rainer; Cordes, Christiana; Horn, Harald; Kampen, Ingo; Kwade, Arno; Neu, Thomas R.; Nörtemann, Bernd

    In various biotechnological processes, filamentous fungi, e.g. Aspergillus niger, are widely applied for the production of high value-added products due to their secretion efficiency. There is, however, a tangled relationship between the morphology of these microorganisms, the transport phenomena and the related productivity. The morphological characteristics vary between freely dispersed mycelia and distinct pellets of aggregated biomass. Hence, advantages and disadvantages for mycel or pellet cultivation have to be balanced out carefully. Due to this inadequate understanding of morphogenesis of filamentous microorganisms, fungal morphology, along with reproducibility of inocula of the same quality, is often a bottleneck of productivity in industrial production. To obtain an optimisation of the production process it is of great importance to gain a better understanding of the molecular and cell biology of these microorganisms as well as the approaches in biochemical engineering and particle technique, in particular to characterise the interactions between the growth conditions, cell morphology, spore-hyphae-interactions and product formation. Advances in particle and image analysis techniques as well as micromechanical devices and their applications to fungal cultivations have made available quantitative morphological data on filamentous cells. This chapter provides the ambitious aspects of this line of action, focussing on the control and characterisation of the morphology, the transport gradients and the approaches to understand the metabolism of filamentous fungi. Based on these data, bottlenecks in the morphogenesis of A. niger within the complex production pathways from gene to product should be identified and this may improve the production yield.

  2. Spatial differentiation of gene expression in Aspergillus niger colony grown for sugar beet pulp utilization

    PubMed Central

    Benoit, Isabelle; Zhou, Miaomiao; Vivas Duarte, Alexandra; Downes, Damien J.; Todd, Richard B.; Kloezen, Wendy; Post, Harm; Heck, Albert J. R.; Maarten Altelaar, A. F.; de Vries, Ronald P.

    2015-01-01

    Degradation of plant biomass to fermentable sugars is of critical importance for the use of plant materials for biofuels. Filamentous fungi are ubiquitous organisms and major plant biomass degraders. Single colonies of some fungal species can colonize massive areas as large as five soccer stadia. During growth, the mycelium encounters heterogeneous carbon sources. Here we assessed whether substrate heterogeneity is a major determinant of spatial gene expression in colonies of Aspergillus niger. We analyzed whole-genome gene expression in five concentric zones of 5-day-old colonies utilizing sugar beet pulp as a complex carbon source. Growth, protein production and secretion occurred throughout the colony. Genes involved in carbon catabolism were expressed uniformly from the centre to the periphery whereas genes encoding plant biomass degrading enzymes and nitrate utilization were expressed differentially across the colony. A combined adaptive response of carbon-catabolism and enzyme production to locally available monosaccharides was observed. Finally, our results demonstrate that A. niger employs different enzymatic tools to adapt its metabolism as it colonizes complex environments. PMID:26314379

  3. Heterologous expression and enzymatic characterization of fructosyltransferase from Aspergillus niger in Pichia pastoris.

    PubMed

    Yang, Hailin; Wang, Yitian; Zhang, Ling; Shen, Wei

    2016-01-25

    In this work, the cDNA encoding fructosyltransferase (FTase) from Aspergillus niger YZ59 (CICIM F0901) was obtained and expressed in the methylotrophic yeast Pichia pastoris strain GS115. The yield of recombinant FTase in a 5-L fermentor reached 1020.0 U/mL after 96 h of induction, which was 1160.4 times higher that of native FTase from A. niger YZ59. The specific activity of recombinant FTase was 6.8×10(4) U/mg. The optimum temperature and pH of the recombinant FTase were 55 °C and 5.5, respectively. The recombinant FTase was stable below 40 °C and at pH from 3.0 to 10.0. Using sucrose as the substrate, the Km and Vmax values of recombinant FTase were 159.8 g/L and 0.66 g/(L min), respectively. The turnover number (kcat) and catalytic efficiency (kcat/Km) of recombinant FTase was 1.1×10(4) min(-1) and 68.8 L/(g min), respectively. The recombinant FTase was slightly activated by 5mM Ni(2+), Mg(2+), K(+), Fe(3+), or Mn(2+), but inhibited by all other metal ions (Na(+), Li(+), Ba(2+), Ca(2+), Zn(2+), and Cu(2+)). The highest yield of fructooligosaccharides for purified FTase reached approximately 343.3 g/L (w/v). This is the first study reporting the heterologous expression of FTases from A. niger in P. pastoris. This study plays an important role in the fructooligosaccharide synthesis industry by recombinant FTases. PMID:25976629

  4. Nigerapyrones A-H, α-pyrone derivatives from the marine mangrove-derived endophytic fungus Aspergillus niger MA-132.

    PubMed

    Liu, Dong; Li, Xiao-Ming; Meng, Li; Li, Chun-Shun; Gao, Shu-Shan; Shang, Zhuo; Proksch, Peter; Huang, Cai-Guo; Wang, Bin-Gui

    2011-08-26

    Eight new α-pyrone derivatives, namely, nigerapyrones A-E (1-5) and nigerapyrones F-H (8-10), along with two known congeners, asnipyrones B (6) and A (7), were isolated from Aspergillus niger MA-132, an endophytic fungus obtained from the fresh tissue of the marine mangrove plant Avicennia marina. The structures of these compounds were elucidated on the basis of spectroscopic analysis. The undescribed geometries of the trisubstituted double bonds (C-9 and C-11) for asnipyrone B (6) have now been explicitly determined, while the incorrect placement of the methyl group at C-5 of asnipyrone A (7) has now been revised at C-3. The cytotoxic activities of the isolated α-pyrone derivatives against eight tumor cell lines as well as antimicrobial activities against two bacteria and four plant-pathogenic fungi of these compounds were evaluated. Compounds 2, 4, 5, and 7 showed weak cytotoxicity against some of the tested tumor cell lines. PMID:21774474

  5. Heterologous Expression of Aspergillus Niger --beta--D-Xylosidase (XInD): Characterization on Lignocellulosic Substrates

    SciTech Connect

    Selig, M. J.; Knoshaug, E. P.; Decker, S. R.; Baker, J. O.; Himmel, M. E.; Adney, W. S.

    2008-01-01

    The gene encoding a glycosyl hydrolase family 3 xylan 1,4-beta-xylosidase, xlnD, was successfully cloned from Aspergillus niger strain ATCC 10864. The recombinant product was expressed in Aspergillus awamori, purified by column chromatography, and verified by matrix-assisted laser desorption ionization, tandem time of flight (MALDI-TOF/TOF) mass spectroscopy of tryptic digests. The T{sub max} was determined using differential scanning microcalorimetry (DSC) to be 78.2 C; the K{sub m} and k{sub cat} were found to be 255 {micro}M and 13.7 s{sup -1}, respectively, using {rho}NP-{Beta}-d-xylopyranoside as substrate. End-product inhibition by d-xylose was also verified and shown to be competitive; the K{sub i} for this inhibition was estimated to be 3.3 mM. XlnD was shown to efficiently hydrolyze small xylo-oligomers to monomeric xylose, making it a critical hydrolytic activity in cases where xylose is to be recovered from biomass conversion processes. In addition, the presence of the XlnD was shown to synergistically enhance the ability of an endoxylanase, XynA from Thermomyces lanuginosus, to convert xylan present in selected pretreated lignocellulosic substrates. Furthermore, the addition of the XynA/XlnD complex was effective in enhancing the ability of a simplified cellulase complex to convert glucan present in the substrates.

  6. Selective transport between heterogeneous hyphal compartments via the plasma membrane lining septal walls of Aspergillus niger.

    PubMed

    Bleichrodt, Robert-Jan; Vinck, Arman; Read, Nick D; Wsten, Han A B

    2015-09-01

    Hyphae of ascomycetes are compartmentalized by septa. The central pore in these septa allows for cytoplasmic streaming. However, many of these pores are closed by Woronin bodies in Aspergillus, which prevents cytoplasmic mixing and thus maintains hyphal heterogeneity. Here, glucose uptake and transport was studied in Aspergillus niger. Glucose uptake was higher in the hyphal population with high transcriptional activity when compared to the population with low transcriptional activity. Glucose was transported from the colony center to the periphery, but not vice versa. This unidirectional flow was similar in the wild-type and the ?hexA strain that does not form Woronin bodies. This indicated that septal plugging by Woronin bodies does not impact long distance glucose transport. Indeed, the glucose analogue 2-NBDG (2-(N-[7-nitrobenz-2-oxa-1,3-diazol-4-yl]amino)-2-deoxyglucose) translocated to neighboring hyphal compartments despite Woronin body mediated plugging of the septum that separated these compartments. Notably, 2-NBDG accumulated in septal cross walls, indicating that intercompartmental glucose transport is mediated by transporters that reside in the plasma membrane lining the septal cross-wall. The presence of such transporters would thus enable selective transport between heterogeneous compartments. PMID:26212073

  7. Biochemical properties of Cu/Zn-superoxide dismutase from fungal strain Aspergillus niger 26

    NASA Astrophysics Data System (ADS)

    Dolashki, Aleksandar; Abrashev, Radoslav; Stevanovic, Stefan; Stefanova, Lilyana; Ali, Syed Abid; Velkova, Ludmila; Hristova, Rumyana; Angelova, Maria; Voelter, Wolfgang; Devreese, Bart; Van Beeumen, Jozef; Dolashka-Angelova, Pavlina

    2008-12-01

    The fungal strain Aspergillus niger produces two superoxide dismutases, Cu/Zn-SOD and Mn-SOD. The primary structure of the Cu/Zn-SOD has been determined by Edman degradation of peptide fragments derived from proteolytic digests. A single chain of the protein, consisting of 153 amino acid residues, reveals a very high degree of structural homology with the amino acid sequences of other Aspergillus Cu/Zn-SODs. The molecular mass of ANSOD, measured by MALDI-MS and ESI-MS, and calculated by its amino acid sequence, was determined to be 15 821 Da. Only one Trp residue, at position 32, and one disulfide bridge were identified. However, neither a Tyr residue nor a carbohydrate chain occupying an N-linkage site (-Asn-Ile-Thr-) were found. Studies on the temperature and pH dependence of fluorescence, and on the temperature dependence of CD spectroscopic properties, confirmed that the enzyme is very stable, which can be explained by the stabilising effect of the disulfide bridge. The enzyme retains about 53% of its activity after incubation for a period of 30 min at 60 C, and 15% at 85 C.

  8. Clarification of Tomato Juice with Polygalacturonase Obtained from Tomato Fruits Infected by Aspergillus niger.

    PubMed

    Ajayi, A A; Peter-Albert, C F; Akeredolu, M; Shokunbi, A A

    2015-02-01

    Two varieties of tomato fruits commonly available in Nigerian markets are the Roma VF and Ibadan local varieties of tomato fruits. The Roma VF fruits are oval in shape. It is a common type of cultivar in the Northern region of Nigeria and it is not susceptible to cracking. The Ibadan local variety of tomato fruits is a local variety commonly found on farmers fields in South-western region of Nigeria. They are highly susceptible to cracking. The Ibadan local variety was employed for this research. There are lots of benefits derived from the consumption of tomato fruits. The fruits can be made into tomato juice clarified with pectinases. Polygalacturonase is one of the pectinases used commercially in the clarification of fruit juice from different fruits. This study examined the production of polygalacturonase during the deterioration of tomato fruits by Aspergillus niger and the role of the purified polygalacturonase in the clarification of tomato juice. Tomato fruits of the Ibadan local variety were inoculated with mycelia discs containing spores of a 96-h-old culture of Aspergillus niger served as the inoculum. The organism from the stock culture was subcultured onto potato dextrose agar plates. The extraction of polygalacturonase after 10 days of incubation at 27 degrees C was carried out by homogenizing the fruits with liquid extractant using the MSE homogenizer after the deteriorated fruits had been chilled for 30 min inside a freezer. Control fruits were similarly treated except that sterile potato dextrose agar served as the inoculum. The effect of different temperature of incubation and different volume of enzyme on the tomato juice from the tomato fruits was investigated. Extracts from the inoculated fruits exhibited appreciable polygalacturonase activity. The juice with polygalacturonase was visually clearer and more voluminous than the juice treated with water for all parameters studied. The highest volume of juice was obtained after an incubation period of 30 min for the tomato fruits. The increase in juice yield can be attributed to the hydrolysis of pectin which releases the sap inside the cells of the pulp. The occurrence of polygalacturonase in tomato tissues infected by A. niger coupled with the trace amount in the non-infected tissues suggests that the enzyme is of fungal origin. The role of the polygalacturonase in the clarification process was established. This study will be very useful for industrial tomato juice production. PMID:26364357

  9. Three new species of Aspergillus section Flavi isolated from almonds and maize in Portugal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three new aflatoxin-producing species belonging to Aspergillus section Flavi are described, Aspergillus mottae, Aspergillus sergii and Aspergillus transmontanensis. These species were isolated from Portuguese almonds and maize. An investigation examining morphology, extrolites and molecular data was...

  10. Identification of Aspergillus (A flavus and A niger) Allergens and Heterogeneity of Allergic Patients' IgE Response.

    PubMed

    Vermani, Maansi; Kandi-Vijayan, Vannan; Kumar-Agarwal, Mahendra

    2015-08-01

    Aspergillus species (A flavus and A niger) are important sources of inhalant allergens. Current  diagnostic  modalities  employ  crude  Aspergillus  extracts  which  only  indicate  the source to which the patient has been sensitized, without identifying the number and type of allergens in crude extracts. We report a study on the identification of major and minor allergens of the two common airborne Aspergillus species and heterogeneity of patients' IgE response to them.Skin prick tests were performed on 300 patients of bronchial asthma and/or allergicrhinitis and 20 healthy volunteers. Allergen specific IgE in patients' sera was estimated by enzyme allergosorbent test (EAST). Immunoblots were performed to identify major/minor allergens of Aspergillus extracts and to study heterogeneity of patients'IgE response to them. Positive cutaneous responses were observed in 17% and 14.7% of patients with A flavusand A niger extracts, respectively. Corresponding EAST positivity was 69.2% and 68.7%. In immunoblots, 5 allergenic proteins were identified in A niger extract, major allergens being 49, 55.4 and 81.5 kDa. Twelve proteins bound patients' IgE in A flavus extract, three being major allergens (13.3, 34 and 37 kDa). The position and slopes of EAST binding and inhibition curves obtained with individual sera varied from patient to patient. The number and molecular weight of IgE-binding proteins in both the Aspergillus extracts varied among patients.These results gave evidence of heterogeneity of patients' IgE response to major/minor Aspergillus allergens. This approach will be helpful to identify disease eliciting molecules in the individual patients (component resolved diagnosis) and may improve allergen-specific immunotherapy. PMID:26547703

  11. Genomic analysis of the aconidial and high-performance protein producer, industrially relevant Aspergillus niger SH2 strain.

    PubMed

    Yin, Chao; Wang, Bin; He, Pan; Lin, Ying; Pan, Li

    2014-05-15

    Aspergillus niger is usually regarded as a beneficial species widely used in biotechnological industry. Obtaining the genome sequence of the widely used aconidial A. niger SH2 strain is of great importance to understand its unusual production capability. In this study we assembled a high-quality genome sequence of A. niger SH2 with approximately 11,517 ORFs. Relatively high proportion of genes enriched for protein expression related FunCat items verify its efficient capacity in protein production. Furthermore, genome-wide comparative analysis between A. niger SH2 and CBS513.88 reveals insights into unique properties of A. niger SH2. A. niger SH2 lacks the gene related with the initiation of asexual sporulation (PrpA), leading to its distinct aconidial phenotype. Frame shift mutations and non-synonymous SNPs in genes of cell wall integrity signaling, ?-1,3-glucan synthesis and chitin synthesis influence its cell wall development which is important for its hyphal fragmentation during industrial high-efficiency protein production. PMID:24630962

  12. Uncovering the Genome-Wide Transcriptional Responses of the Filamentous Fungus Aspergillus niger to Lignocellulose Using RNA Sequencing

    PubMed Central

    Gaddipati, Sanyasi; Kokolski, Matthew; Malla, Sunir; Blythe, Martin J.; Ibbett, Roger; Campbell, Maria; Liddell, Susan; Aboobaker, Aziz; Tucker, Gregory A.; Archer, David B.

    2012-01-01

    A key challenge in the production of second generation biofuels is the conversion of lignocellulosic substrates into fermentable sugars. Enzymes, particularly those from fungi, are a central part of this process, and many have been isolated and characterised. However, relatively little is known of how fungi respond to lignocellulose and produce the enzymes necessary for dis-assembly of plant biomass. We studied the physiological response of the fungus Aspergillus niger when exposed to wheat straw as a model lignocellulosic substrate. Using RNA sequencing we showed that, 24 hours after exposure to straw, gene expression of known and presumptive plant cell walldegrading enzymes represents a huge investment for the cells (about 20% of the total mRNA). Our results also uncovered new esterases and surface interacting proteins that might form part of the fungal arsenal of enzymes for the degradation of plant biomass. Using transcription factor deletion mutants (xlnR and creA) to study the response to both lignocellulosic substrates and low carbon source concentrations, we showed that a subset of genes coding for degradative enzymes is induced by starvation. Our data support a model whereby this subset of enzymes plays a scouting role under starvation conditions, testing for available complex polysaccharides and liberating inducing sugars, that triggers the subsequent induction of the majority of hydrolases. We also showed that antisense transcripts are abundant and that their expression can be regulated by growth conditions. PMID:22912594

  13. Uncovering the genome-wide transcriptional responses of the filamentous fungus Aspergillus niger to lignocellulose using RNA sequencing.

    PubMed

    Delmas, Stphane; Pullan, Steven T; Gaddipati, Sanyasi; Kokolski, Matthew; Malla, Sunir; Blythe, Martin J; Ibbett, Roger; Campbell, Maria; Liddell, Susan; Aboobaker, Aziz; Tucker, Gregory A; Archer, David B

    2012-01-01

    A key challenge in the production of second generation biofuels is the conversion of lignocellulosic substrates into fermentable sugars. Enzymes, particularly those from fungi, are a central part of this process, and many have been isolated and characterised. However, relatively little is known of how fungi respond to lignocellulose and produce the enzymes necessary for dis-assembly of plant biomass. We studied the physiological response of the fungus Aspergillus niger when exposed to wheat straw as a model lignocellulosic substrate. Using RNA sequencing we showed that, 24 hours after exposure to straw, gene expression of known and presumptive plant cell wall-degrading enzymes represents a huge investment for the cells (about 20% of the total mRNA). Our results also uncovered new esterases and surface interacting proteins that might form part of the fungal arsenal of enzymes for the degradation of plant biomass. Using transcription factor deletion mutants (xlnR and creA) to study the response to both lignocellulosic substrates and low carbon source concentrations, we showed that a subset of genes coding for degradative enzymes is induced by starvation. Our data support a model whereby this subset of enzymes plays a scouting role under starvation conditions, testing for available complex polysaccharides and liberating inducing sugars, that triggers the subsequent induction of the majority of hydrolases. We also showed that antisense transcripts are abundant and that their expression can be regulated by growth conditions. PMID:22912594

  14. Hemicellulase production by Aspergillus niger DSM 26641 in hydrothermal palm oil empty fruit bunch hydrolysate and transcriptome analysis.

    PubMed

    Ottenheim, Christoph; Verdejo, Carl; Zimmermann, Wolfgang; Wu, Jin Chuan

    2014-12-01

    Palm oil empty fruit bunches (EFB) is an abundant and cheap lignocellulose material in Southeast Asia. Its use as the sole medium for producing lignocellulose-hydrolyzing enzymes would increase its commercial value. A newly isolated Aspergillus niger DSM 26641 was investigated for its capability of producing hemicellulases in EFB hydrolysate obtained by treatment with pressurized hot water (1-20%, w/v) at 120-180°C in a 1 L Parr reactor for 10-60 min. The optimal hydrolysate for the fungal growth and endoxylanase production was obtained when 10% (w/v) of empty fruit bunch was treated at 120°C or 150°C for 10 min, giving an endoxylanase activity of 24.5 mU ml(-1) on RBB-Xylan and a saccharification activity of 5 U ml(-1) on xylan (DNS assay). When the hydrolysates were produced at higher temperatures, longer treatment times or higher biomass contents, only less than 20% of the above maximal endoxylanase activity was detected, possibly due to the higher carbohydrate concentrations in the medium. Transcriptome analysis showed that 3 endoxylanases (expression levels 59-100%, the highest level was set as 100%), 2 β-xylosidases (4%), 4 side chain-cleaving arabinofuranosidases (1-95%), 1 acetyl xylan esterase (9%) and 2 ferulic acid esterases (0.3-9%) were produced together. PMID:24958131

  15. Involvement of Physical Parameters in Medium Improvement for Tannase Production by Aspergillus niger FETL FT3 in Submerged Fermentation

    PubMed Central

    Darah, I.; Sumathi, G.; Jain, K.; Hong, Lim Sheh

    2011-01-01

    Aspergillus niger FETL FT3, a local extracellular tannase producer strain that was isolated from one of dumping sites of tannin-rich barks of Rhizophora apiculata in Perak, Malaysia. This fungus was cultivated in 250 mL Erlenmeyer flask under submerged fermentation system. Various physical parameters were studied in order to maximize the tannase production. Maximal yield of tannase production, that is, 2.81 U per mL was obtained on the fourth day of cultivation when the submerged fermentation was carried out using liquid Czapek-Dox medium containing (percent; weight per volume) 0.25% NaNO3, 0.1% KH2PO4, 0.05% MgSO4 ·7H2O, 0.05% KCl, and 1.0% tannic acid. The physical parameters used initial medium pH of 6.0, incubation temperature of 30°C, agitation speed of 200 rpm and inoculums size of 6 × 106 spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment. PMID:21826273

  16. Antifungal effects of Ficus sycomorus and Pergularia tomentosa aqueous extracts on some organs in Bufo regularis treated with Aspergillus niger.

    PubMed

    Bekheet, Souad H M; Abdel-Motaal, Fatma F; Mahalel, Usama A

    2011-12-01

    The antifungal efficacy of Ficus sycomorus and Pergularia tomentosa plant extracts on Bufo regularis experimentally infected with Aspergillus niger was studied. After an oral administration of the pathogen for 15 days, the blood, kidney and liver were examined. Treatment with A. niger produced a reduction in red blood count cells and hemoglobin content. Also, both livers and kidneys revealed marked destruction and degenerative changes. These changes included congestion of blood vessels, leukocytic infiltration, and cytoplasmic vacuolization of the hepatocytes. As well as complete destruction of the cellular boundaries of the tubular epithelia, inflammatory leukocytes between the intertubular spaces, destruction and necrosis in renal tubule cells and the swollen glomeruli with wide glomerular spaces were seen. Pretreatment with F. sycomorus and P. tomentosa plant extracts 1h prior the administration of A. niger for two weeks improved blood parameters and protected against hepatic and renal damage as observed from histological examination and reduced spore numbers in culture media on these organs. PMID:21996552

  17. Niger.

    PubMed

    1987-06-01

    Niger is two-thirds Sahara desert and the rest savannah with an area irrigated by the Niger River valley. The 6.2 million people are therefore either nomadic herdsmen or subsistence farmers, coping with a hot, dry climate. There are 5 or more ethnic groups, 2 main languages other than the official French, and most people are Muslim. The growth rate is 3.1%; children make up 45% of the population; infant mortality is 145/1000; life expectancy is 44.5 years. The constitutional government has been suspended by a military regime. A multi-layered structure called "development society" has been instituted. Per capita income is about $265. Niger has uranium, coal, iron, tin and phosphates, and farm products include peanuts, millet, sorghum, beans, cotton, rice and cowpeas. Niger received assistance from France, US, West Germany, Canada, Saudi Arabia, as well as international organizations and military assistance from several countries. PMID:12177951

  18. Effect of temperature and water activity on the production of fumonisins by Aspergillus niger and different Fusarium species

    PubMed Central

    2009-01-01

    Background 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. Results 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. Conclusion 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. PMID:20043849

  19. Mycelium-bound lipase production from Aspergillus niger MYA 135, and its potential applications for the transesterification of ethanol.

    PubMed

    Colin, Vernica Leticia; Baigor, Mario Domingo; Pera, Licia Mara

    2011-06-01

    The potential biotechnological applications of both constitutive and inducible lipase sources from Aspergillus niger MYA 135 were evaluated. To this end, the effect of environmental conditions on mycelium-bound lipase production from this strain was studied, when cultured either in the absence or presence of 2% olive oil. It was previously reported that mycelium-bound lipase from Aspergillus niger MYA 135 possess high stability in reaction mixtures containing ethanol; which could be especially important for their use in biodiesel synthesis. In this connection, the performance of the lipase sources produced in the transesterification of ethanol using p-nitrophenyl palmitate as acyl donor was also explored. Under our assay conditions, hydrolytic and synthetic activity of the mycelia produced in the absence or presence of olive oil were not highly correlated. While the hydrolytic activity was strongly increased by the addition of lipid to the culture medium, the best performance in the transesterification reactions of ethanol were associated with mycelia produced in absence of olive oil. Interestingly, the supplementation of the culture medium with Fe(+3) increased the transesterification activity by 71%, as compared to the activity previously reported for this strain. Therefore, the constitutive lipase sources from Aspergillus niger MYA 135 are considered to be promising for industrial biodiesel-fuel production. PMID:21298682

  20. Heterogeneous Expression and Functional Characterization of Cellulose-Degrading Enzymes from Aspergillus niger for Enzymatic Hydrolysis of Alkali Pretreated Bamboo Biomass.

    PubMed

    Ali, Nasir; Ting, Zhang; Li, Hailong; Xue, Yong; Gan, Lihui; Liu, Jian; Long, Minnan

    2015-09-01

    Enzymatic hydrolysis of cellulosic biomass has caught much attention because of modest reaction conditions and environment friendly conditions. To reduce the cost and to achieve good quantity of cellulases, a heterologous expression system is highly favored. In this study, cellulose-degrading enzymes, GH3 family ?-glucosidase (BGL), GH7 family-related cellobiohydrolases (CBHs), and endoglucanase (EG) from a newly isolated Aspergillus niger BE-2 are highly expressed in Pichia pastoris GS115. The strain produced EG, CBHs, and BGL enzymatic concentration of 0.56, 0.11, and 22IU/mL, respectively. Mode of actions of the recombinant enzymes for substrate specificity and end product analysis are verified and found specific for cellulose degradation. Bamboo biomass saccharification with A. niger cellulase released a high level of fermentable sugars. Hydrolysis parameters are optimized to obtain reducing sugars level of 3.18g/L. To obtain reducing sugars from a cellulosic biomass, A. niger could be a good candidate for enzymes resource of cellulase to produce reducing sugars from a cellulosic biomass. This study also facilitates the development of highly efficient enzyme cocktails for the bioconversion of lignocellulosic biomass into monosaccharides and oligosaccharides. PMID:26202492

  1. Aspergillus niger ?-Glucosidase Has a Cellulase-like Tadpole Molecular Shape

    PubMed Central

    Lima, Marisa A.; Oliveira-Neto, Mario; Kadowaki, Marco Antonio S.; Rosseto, Flavio R.; Prates, Erica T.; Squina, Fabio M.; Leme, Adriana F. P.; Skaf, Munir S.; Polikarpov, Igor

    2013-01-01

    Aspergillus niger is known to secrete large amounts of ?-glucosidases, which have a variety of biotechnological and industrial applications. Here, we purified an A. niger ?-glucosidase (AnBgl1) and conducted its biochemical and biophysical analyses. Purified enzyme with an apparent molecular mass of 116 kDa forms monomers in solution as judged by native gel electrophoresis and has a pI value of 4.55, as found for most of the fungi of ?-glucosidases. Surprisingly, the small angle x-ray experiments reveal that AnBgl1 has a tadpole-like structure, with the N-terminal catalytic domain and C-terminal fibronectin III-like domain (FnIII) connected by the long linker peptide (?100 amino acid residues) in an extended conformation. This molecular organization resembles the one adopted by other cellulases (such as cellobiohydrolases, for example) that frequently contain a catalytic domain linked to the cellulose-binding module that mediates their binding to insoluble and polymeric cellulose. The reasons why AnBgl1, which acts on the small soluble substrates, has a tadpole molecular shape are not entirely clear. However, our enzyme pulldown assays with different polymeric substrates suggest that AnBgl1 has little or no capacity to bind to and to adsorb cellulose, xylan, and starch, but it has high affinity to lignin. Molecular dynamics simulations suggested that clusters of residues located in the C-terminal FnIII domain interact strongly with lignin fragments. The simulations showed that numerous arginine residues scattered throughout the FnIII surface play an important role in the interaction with lignin by means of cation-? stacking with the lignin aromatic rings. These results indicate that the C-terminal FnIII domain could be operational for immobilization of the enzyme on the cell wall and for the prevention of unproductive binding of cellulase to the biomass lignin. PMID:24064212

  2. Fed-batch production of gluconic acid by terpene-treated Aspergillus niger spores.

    PubMed

    Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian

    2008-12-01

    Aspergillus niger spores were used as catalyst in the bioconversion of glucose to gluconic acid. Spores produced by solid-state fermentation were treated with 15 different terpenes including monoterpenes and monoterpenoids to permeabilize and inhibit spore germination. It was found that spore membrane permeability is significantly increased by treatment with terpenoids when compared to monoterpenes. Best results were obtained with citral and isonovalal. Studies were carried out to optimize spores concentration (10(7)-10(10) spores/mL), terpene concentrations in the bioconversion medium and time of exposure (1-18 h) needed for permeabilization of spores. Fed-batch production of gluconate was done in a bioreactor with the best conditions [10(9) spores/mL of freeze-thawed spores treated with citral (3% v/v) for 5 h] followed by sequential additions of glucose powder and pH-regulated with a solution containing 2 mol/L of either NaOH or KOH. Bioconversion performance of the spore enzyme was compared with the commercial glucose oxidase at 50, 60, and 70 degrees C. Results showed that the spore enzyme was comparatively stable at 60 degrees C. It was also found that the spores could be reutilized for more than 14 cycles with almost similar reaction rate. Similar biocatalytic activity was rendered by spores even after its storage of 1 year at -20 degrees C. This study provided an experimental evidence of the significant catalytic role played by A. niger spore in bioconversion of glucose to gluconic acid with high yield and stability, giving protection to glucose oxidase. PMID:18427736

  3. Pectinase production by solid fermentation from Aspergillus niger by a new prescription experiment.

    PubMed

    Debing, Jing; Peijun, Li; Stagnitti, Frank; Xianzhe, Xiong; Li, Ling

    2006-06-01

    The Ordos Plateau in China is covered with up to 300,000 ha of peashrub (Caragana) which is the dominant natural vegetation and ideal for fodder production. To exploit peashrub fodder, it is crucially important to optimize the culture conditions, especially culture substrate to produce pectinase complex. In this study, a new prescription process was developed. The process, based on a uniform experimental design, first optimizes the solid substrate and second, after incubation, applies two different temperature treatments (30 degrees C for the first 30 h and 23 degrees C for the second 42 h) in the fermentation process. A multivariate regression analysis is applied to a number of independent variables (water, wheat bran, rice dextrose, ammonium sulfate, and Tween 80) to develop a predictive model of pectinase activity. A second-degree polynomial model is developed which accounts for an excellent proportion of the explained variation (R(2)=97.7%). Using unconstrained mathematical programming, an optimized substrate prescription for pectinase production is subsequently developed. The mathematical analysis revealed that the optimal formula for pectinase production from Aspergillus niger by solid fermentation under the conditions of natural aeration, natural substrate pH (about 6.5), and environmental humidity of 60% is rice dextrose 8%, wheat bran 24%, ammonium sulfate ((NH(4))(2)SO(4)) 6%, and water 61%. Tween 80 was found to have a negative effect on the production of pectinase in solid substrate. With this substrate prescription, pectinase produced by solid fermentation of A. niger reached 36.3 IU/(gDM). Goats fed on the pectinase complex obtain an incremental increase of 0.47 kg day(-1) during the initial 25 days of feeding, which is a very promising new feeding prospect for the local peashrub. It is concluded that the new formula may be very useful for the sustainable development of arid and semiarid pastures such as those of the Ordos Plateau. PMID:16406599

  4. Primary cutaneous aspergillosis due to Aspergillus niger in an immunocompetent patient.

    PubMed

    Mohapatra, S; Xess, I; Swetha, J V; Tanveer, N; Asati, D; Ramam, M; Singh, M K

    2009-01-01

    Primary cutaneous aspergillosis is a rare entity, usually caused by A. fumigatus and A. flavus . Here, we present such a case, manifested by ulceration due to A. niger, which remained undiagnosed for a prolonged period. The immunological status was intact, although the patient had associated severe fungal infection. Recurrence of the lesion occurred despite repeated anti-fungal therapies. Anti fungal testing was done based on the broth dilution (M-38A, NCCLS, USA) method. The culture isolate was found to be sensitive to fluconazole and amphotericin B. Continuation of antifungal therapy improved the symptoms, reducing the size of the lesion. PMID:19736412

  5. Secretion and properties of a hybrid Kluyveromyces lactis-Aspergillus niger ?-galactosidase

    PubMed Central

    Rodrguez, ngel Pereira; Leiro, Rafael Fernndez; Trillo, M Cristina; Cerdn, M Esperanza; Siso, M Isabel Gonzlez; Becerra, Manuel

    2006-01-01

    Background The ?-galactosidase from Kluyveromyces lactis is a protein of outstanding biotechnological interest in the food industry and milk whey reutilization. However, due to its intracellular nature, its industrial production is limited by the high cost associated to extraction and downstream processing. The yeast-system is an attractive method for producing many heterologous proteins. The addition of a secretory signal in the recombinant protein is the method of choice to sort it out of the cell, although biotechnological success is not guaranteed. The cell wall acting as a molecular sieve to large molecules, culture conditions and structural determinants present in the protein, all have a decisive role in the overall process. Protein engineering, combining domains of related proteins, is an alternative to take into account when the task is difficult. In this work, we have constructed and analyzed two hybrid proteins from the ?-galactosidase of K. lactis, intracellular, and its Aspergillus niger homologue that is extracellular. In both, a heterologous signal peptide for secretion was also included at the N-terminus of the recombinant proteins. One of the hybrid proteins obtained has interesting properties for its biotechnological utilization. Results The highest levels of intracellular and extracellular ?-galactosidase were obtained when the segment corresponding to the five domain of K. lactis ?-galactosidase was replaced by the corresponding five domain of the A. niger ?-galactosidase. Taking into account that this replacement may affect other parameters related to the activity or the stability of the hybrid protein, a thoroughly study was performed. Both pH (6.5) and temperature (40C) for optimum activity differ from values obtained with the native proteins. The stability was higher than the corresponding to the ?-galactosidase of K. lactis and, unlike this, the activity of the hybrid protein was increased by the presence of Ni2+. The affinity for synthetic (ONPG) or natural (lactose) substrates was higher in the hybrid than in the native K. lactis ?-galactosidase. Finally, a structural-model of the hybrid protein was obtained by homology modelling and the experimentally determined properties of the protein were discussed in relation to it. Conclusion A hybrid protein between K. lactis and A. niger ?-galactosidases was constructed that increases the yield of the protein released to the growth medium. Modifications introduced in the construction, besides to improve secretion, conferred to the protein biochemical characteristics of biotechnological interest. PMID:17176477

  6. Comparative Secretome Analysis of Trichoderma reesei and Aspergillus niger during Growth on Sugarcane Biomass

    PubMed Central

    Borin, Gustavo Pagotto; Sanchez, Camila Cristina; de Souza, Amanda Pereira; de Santana, Eliane Silva; de Souza, Aline Tieppo; Leme, Adriana Franco Paes; Squina, Fabio Marcio; Buckeridge, Marcos; Goldman, Gustavo Henrique; Oliveira, Juliana Velasco de Castro

    2015-01-01

    Background Our dependence on fossil fuel sources and concern about the environment has generated a worldwide interest in establishing new sources of fuel and energy. Thus, the use of ethanol as a fuel is advantageous because it is an inexhaustible energy source and has minimal environmental impact. Currently, Brazil is the world's second largest producer of ethanol, which is produced from sugarcane juice fermentation. However, several studies suggest that Brazil could double its production per hectare by using sugarcane bagasse and straw, known as second-generation (2G) bioethanol. Nevertheless, the use of this biomass presents a challenge because the plant cell wall structure, which is composed of complex sugars (cellulose and hemicelluloses), must be broken down into fermentable sugar, such as glucose and xylose. To achieve this goal, several types of hydrolytic enzymes are necessary, and these enzymes represent the majority of the cost associated with 2G bioethanol processing. Reducing the cost of the saccharification process can be achieved via a comprehensive understanding of the hydrolytic mechanisms and enzyme secretion of polysaccharide-hydrolyzing microorganisms. In many natural habitats, several microorganisms degrade lignocellulosic biomass through a set of enzymes that act synergistically. In this study, two fungal species, Aspergillus niger and Trichoderma reesei, were grown on sugarcane biomass with two levels of cell wall complexity, culm in natura and pretreated bagasse. The production of enzymes related to biomass degradation was monitored using secretome analyses after 6, 12 and 24 hours. Concurrently, we analyzed the sugars in the supernatant. Results Analyzing the concentration of monosaccharides in the supernatant, we observed that both species are able to disassemble the polysaccharides of sugarcane cell walls since 6 hours post-inoculation. The sugars from the polysaccharides such as arabinoxylan and β-glucan (that compose the most external part of the cell wall in sugarcane) are likely the first to be released and assimilated by both species of fungi. At all time points tested, A. niger produced more enzymes (quantitatively and qualitatively) than T. reesei. However, the most important enzymes related to biomass degradation, including cellobiohydrolases, endoglucanases, β-glucosidases, β-xylosidases, endoxylanases, xyloglucanases, and α-arabinofuranosidases, were identified in both secretomes. We also noticed that the both fungi produce more enzymes when grown in culm as a single carbon source. Conclusion Our work provides a detailed qualitative and semi-quantitative secretome analysis of A. niger and T. reesei grown on sugarcane biomass. Our data indicate that a combination of enzymes from both fungi is an interesting option to increase saccharification efficiency. In other words, these two fungal species might be combined for their usage in industrial processes. PMID:26053961

  7. Phytotoxicity of lignanamides isolated from the seeds of Hyoscyamus niger.

    PubMed

    Zhang, Wen-Na; Luo, Jian-Guang; Kong, Ling-Yi

    2012-02-22

    Bioassay-guided fractionation of phytotoxic extracts prepared from the seeds of Hyoscyamus niger led to the isolation of three new lignanamides (1-3), along with six known lignanamides (4-9). The structures of the new compounds were determined by spectroscopic methods, including 1D and 2D nuclear magnetic resonance techniques, and high-resolution electrospray ionization mass spectrometry. The bioactivity analysis of the isolated compounds showed that compound 3 exhibited significant inhibition on the germination and radical elongation of Allium fistulosum at 10(-4) M concentration. PMID:22280058

  8. Cloning, expression, characterization, and nucleophile identification of family 3, Aspergillus niger beta-glucosidase.

    PubMed

    Dan, S; Marton, I; Dekel, M; Bravdo, B A; He, S; Withers, S G; Shoseyov, O

    2000-02-18

    The beta-glucosidase from Aspergillus niger (CMI CC 324262) was purified, and an N-terminal sequence and two internal sequences were determined. BglI genomic gene and the cDNA were cloned from a genomic library and by reverse transcriptase-polymerase chain reaction, respectively. The cDNA was successfully expressed in Saccharomyces cerevisiae and Pichia pastoris. Sequence analysis revealed that the gene encodes a 92-kDa enzyme that is a member of glycosidase family 3. (1)H-NMR analysis of the reaction catalyzed by this enzyme confirmed that, in common with other family 3 glycosidases, this enzyme hydrolyzes with net retention of anomeric configuration. Accordingly, the enzyme was inactivated by 2-deoxy-2-fluoro beta-glucosyl fluoride, with kinetic parameters of k(i) = 4.5 min(-1), K(I) = 35.4 mM, through the trapping of a covalent glycosyl enzyme intermediate. The catalytic competence of this intermediate was demonstrated by the fact that incubation with linamarin resulted in reactivation, presumably via a transglycosylation mechanism. Peptic digestion of the 2-deoxy-2-fluoroglucosyl enzyme and subsequent analysis of high pressure liquid chromatography eluates by electrospray ionization triple quadrupole mass spectrometry in the neutral loss mode allowed the localization of a 2-deoxy-2-fluoroglucosyl-peptide. Sequence determination of this labeled peptide by tandem mass spectrometry in the daughter ion scan mode permitted the identification of Asp-261 as the catalytic nucleophile within the sequence VMSDW. Asp-261 is fully conserved within this family, consistent with its key role, and aligns with the aspartic acid residue previously identified in the Aspergillus wentii enzyme by labeling with conduritol B epoxide (Bause, E., and Legler, G. (1974) Hoppe-Seyler's Z. Physiol. Chem. 355, 438-442). PMID:10671536

  9. Synergistic effect of Aspergillus niger and Trichoderma reesei enzyme sets on the saccharification of wheat straw and sugarcane bagasse.

    PubMed

    van den Brink, Joost; Maitan-Alfenas, Gabriela Piccolo; Zou, Gen; Wang, Chengshu; Zhou, Zhihua; Guimares, Valria Monteze; de Vries, Ronald P

    2014-10-01

    Plant-degrading enzymes can be produced by fungi on abundantly available low-cost plant biomass. However, enzymes sets after growth on complex substrates need to be better understood, especially with emphasis on differences between fungal species and the influence of inhibitory compounds in plant substrates, such as monosaccharides. In this study, Aspergillus niger and Trichoderma reesei were evaluated for the production of enzyme sets after growth on two "second generation" substrates: wheat straw (WS) and sugarcane bagasse (SCB). A. niger and T. reesei produced different sets of (hemi-)cellulolytic enzymes after growth on WS and SCB. This was reflected in an overall strong synergistic effect in releasing sugars during saccharification using A. niger and T. reesei enzyme sets. T. reesei produced less hydrolytic enzymes after growth on non-washed SCB. The sensitivity to non-washed plant substrates was not reduced by using CreA/Cre1 mutants of T. reesei and A. niger with a defective carbon catabolite repression. The importance of removing monosaccharides for producing enzymes was further underlined by the decrease in hydrolytic activities with increased glucose concentrations in WS media. This study showed the importance of removing monosaccharides from the enzyme production media and combining T. reesei and A. niger enzyme sets to improve plant biomass saccharification. PMID:25116172

  10. Study of Spanish Grape Mycobiota and Ochratoxin A Production by Isolates of Aspergillus tubingensis and Other Members of Aspergillus Section Nigri

    PubMed Central

    Medina, Angel; Mateo, Rufino; Lpez-Ocaa, Laura; Valle-Algarra, Francisco Manuel; Jimnez, Misericordia

    2005-01-01

    The native mycobiota of five grape varieties grown in Spain has been studied. Four (Bobal, Tempranillo, Garnacha, and Monastrell) were red varieties and one (Moscatel) was white. The main fungal genera isolated were Alternaria, Cladosporium, and Aspergillus. The isolation frequency of Aspergillus spp. section Nigri in contaminated samples was 82%. Ochratoxin A (OTA) production was assessed using yeast extract-sucrose broth supplemented with 5% bee pollen. Cultures of 205 isolates from this section showed that 74.2% of Aspergillus carbonarius and 14.3% of Aspergillus tubingensis isolates produced OTA at levels ranging from 1.2 to 3,530 ng/ml and from 46.4 to 111.5 ng/ml, respectively. No Aspergillus niger isolate had the ability to produce this toxin under the conditions assayed. Identification of the A. niger aggregate isolates was based on PCR amplification of 5.8S rRNA genes and its two intergenic spacers, internal transcribed spacer 1 (ITS1) and ITS2, followed by digestion with restriction endonuclease RsaI of the PCR products. The restriction patterns were compared with those from strains of A. niger CECT 2807 and A. tubingensis CECT 20393, held at the Spanish Collection of Type Cultures. DNA sequencing of the ITS1-5.8S rRNA gene-ITS2 region of the OTA-producing isolates of A. tubingensis matched 99 to 100% with the nucleotide sequence of strain A. tubingensis CBS 643.92. OTA determination was accomplished by liquid chromatography with fluorescence detection. OTA confirmation was carried out by liquid chromatography coupled to ion trap mass spectrometry. The results showed that there are significant differences with regard to the isolation frequency of ochratoxinogenic fungi in the different grape varieties. These differences were uncorrelated to berry color. The ability of A. tubingensis to produce OTA and the influence of grape variety on the occurrence of OTA-producing fungi in grapes are described in this report for the first time. PMID:16085865

  11. Study of Spanish grape mycobiota and ochratoxin A production by Isolates of Aspergillus tubingensis and other members of Aspergillus section Nigri.

    PubMed

    Medina, Angel; Mateo, Rufino; Lpez-Ocaa, Laura; Valle-Algarra, Francisco Manuel; Jimnez, Misericordia

    2005-08-01

    The native mycobiota of five grape varieties grown in Spain has been studied. Four (Bobal, Tempranillo, Garnacha, and Monastrell) were red varieties and one (Moscatel) was white. The main fungal genera isolated were Alternaria, Cladosporium, and Aspergillus. The isolation frequency of Aspergillus spp. section Nigri in contaminated samples was 82%. Ochratoxin A (OTA) production was assessed using yeast extract-sucrose broth supplemented with 5% bee pollen. Cultures of 205 isolates from this section showed that 74.2% of Aspergillus carbonarius and 14.3% of Aspergillus tubingensis isolates produced OTA at levels ranging from 1.2 to 3,530 ng/ml and from 46.4 to 111.5 ng/ml, respectively. No Aspergillus niger isolate had the ability to produce this toxin under the conditions assayed. Identification of the A. niger aggregate isolates was based on PCR amplification of 5.8S rRNA genes and its two intergenic spacers, internal transcribed spacer 1 (ITS1) and ITS2, followed by digestion with restriction endonuclease RsaI of the PCR products. The restriction patterns were compared with those from strains of A. niger CECT 2807 and A. tubingensis CECT 20393, held at the Spanish Collection of Type Cultures. DNA sequencing of the ITS1-5.8S rRNA gene-ITS2 region of the OTA-producing isolates of A. tubingensis matched 99 to 100% with the nucleotide sequence of strain A. tubingensis CBS 643.92. OTA determination was accomplished by liquid chromatography with fluorescence detection. OTA confirmation was carried out by liquid chromatography coupled to ion trap mass spectrometry. The results showed that there are significant differences with regard to the isolation frequency of ochratoxinogenic fungi in the different grape varieties. These differences were uncorrelated to berry color. The ability of A. tubingensis to produce OTA and the influence of grape variety on the occurrence of OTA-producing fungi in grapes are described in this report for the first time. PMID:16085865

  12. Genetic diversity of Aspergillus species isolated from onychomycosis and Aspergillus hongkongensis sp. nov., with implications to antifungal susceptibility testing.

    PubMed

    Tsang, Chi-Ching; Hui, Teresa W S; Lee, Kim-Chung; Chen, Jonathan H K; Ngan, Antonio H Y; Tam, Emily W T; Chan, Jasper F W; Wu, Andrea L; Cheung, Mei; Tse, Brian P H; Wu, Alan K L; Lai, Christopher K C; Tsang, Dominic N C; Que, Tak-Lun; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

    2016-02-01

    Thirteen Aspergillus isolates recovered from nails of 13 patients (fingernails, n=2; toenails, n=11) with onychomycosis were characterized. Twelve strains were identified by multilocus sequencing as Aspergillus spp. (Aspergillus sydowii [n=4], Aspergillus welwitschiae [n=3], Aspergillus terreus [n=2], Aspergillus flavus [n=1], Aspergillus tubingensis [n=1], and Aspergillus unguis [n=1]). Isolates of A. terreus, A. flavus, and A. unguis were also identifiable by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The 13th isolate (HKU49(T)) possessed unique morphological characteristics different from other Aspergillus spp. Molecular characterization also unambiguously showed that HKU49(T) was distinct from other Aspergillus spp. We propose the novel species Aspergillus hongkongensis to describe this previously unknown fungus. Antifungal susceptibility testing showed most Aspergillus isolates had low MICs against itraconazole and voriconazole, but all Aspergillus isolates had high MICs against fluconazole. A diverse spectrum of Aspergillus species is associated with onychomycosis. Itraconazole and voriconazole are probably better drug options for Aspergillus onychomycosis. PMID:26658315

  13. Effect of Aspergillus niger xylanase on dough characteristics and bread quality attributes.

    PubMed

    Ahmad, Zulfiqar; Butt, Masood Sadiq; Ahmed, Anwaar; Riaz, Muhammad; Sabir, Syed Mubashar; Farooq, Umar; Rehman, Fazal Ur

    2014-10-01

    The present study was conducted to investigate the impact of various treatments of xylanase produced by Aspergillus niger applied in bread making processes like during tempering of wheat kernels and dough mixing on the dough quality characteristics i.e. dryness, stiffness, elasticity, extensibility, coherency and bread quality parameters i.e. volume, specific volume, density, moisture retention and sensory attributes. Different doses (200, 400, 600, 800 and 1,000 IU) of purified enzyme were applied to 1 kg of wheat grains during tempering and 1 kg of flour (straight grade flour) during mixing of dough in parallel. The samples of wheat kernels were agitated at different intervals for uniformity in tempering. After milling and dough making of both types of flour (having enzyme treatment during tempering and flour mixing) showed improved dough characteristics but the improvement was more prominent in the samples receiving enzyme treatment during tempering. Moreover, xylanase decreased dryness and stiffness of the dough whereas, resulted in increased elasticity, extensibility and coherency and increase in volume & decrease in bread density. Xylanase treatments also resulted in higher moisture retention and improvement of sensory attributes of bread. From the results, it is concluded that dough characteristics and bread quality improved significantly in response to enzyme treatments during tempering as compared to application during mixing. PMID:25328183

  14. Response surface optimization of fermentation conditions for producing xylanase by Aspergillus niger SL-05.

    PubMed

    Liu, Cheng; Sun, Zhong-Tao; Du, Jin-Hua; Wang, Jian

    2008-07-01

    Fermentation conditions were statistically optimized for producing extracellular xylanase by Aspergillus niger SL-05 using apple pomace and cotton seed meal. The primary study shows that culture medium with a 1:1 ratio of apple pomace and cotton seed meal (carbon and nitrogen sources) yielded maximal xylanase activity. Three significant factors influencing xylanase production were identified as urea, KH(2)PO(4), and initial moisture content using Plackett-Burman design study. The effects of these three factors were further investigated using a design of rotation-regression-orthogonal combination. The optimized conditions by response surface analysis were 2.5% Urea, 0.09% KH(2)PO(4), and 62% initial moisture content. The analysis of variance indicated that the established model was significant (P < 0.05), "while" or "and" the lack of fit was not significant. Under the optimized conditions, the model predicted 4,998 IU/g dry content, whereas validation experiments produced an enzymatic activity of xylanase at 5,662 IU/g dry content after 60 h fermentation. This study innovatively developed a fermentation medium and process to utilize inexpensive agro-industrial wastes to produce a high yield of xylanase. PMID:18309527

  15. Development of miconazole nitrate containing chitosan microcapsules and their anti-Aspergillus niger activity.

    PubMed

    Yuen, C W M; Kan, C W; Cheuk, K L; Cheung, H C; Cheng, S Y; Yip, J; Lam, P L

    2012-01-01

    In this article, we report the development of chitosan/miconazole nitrate microcapsules. Four miconazole nitrate ratios including 12.5, 25, 50 and 100?mg were performed in the chitosan-based microencapsulation system. Chitosan microcapsules with the drug input of 25?mg showed the highest encapsulation efficiency (52.47%) and acceptable mean particle size (5.65?m) when compared with those of 12.5, 50 and 100?mg. Fourier transform infrared spectroscopic spectrum proved the entrapment of miconazole nitrate into chitosan microcapsules. The antifungal result demonstrated that microcapsules containing 75?g miconazole nitrate possessed comparable anti-Aspergillus niger activity as the commercial ointment. The growth inhibition of miconazole nitrate containing chitosan microcapsules towards human skin keratinocytes was found to be dose dependent. A total of 75?g of miconazole nitrate containing microcapsules revealed about 25% of growth inhibition while that of 150?g showed approximately 70% of growth inhibition. Special monitoring should be taken if a higher dose of miconazole nitrate was used to develop the microcapsules. PMID:22172026

  16. The influence of metal ions on malic enzyme activity and lipid synthesis in Aspergillus niger.

    PubMed

    Jernejc, Katarina; Legisa, Matic

    2002-12-17

    In the presence of copper significant induction of citric acid overflow was observed, while concomitantly lower levels of total lipids were detected in the cells. Its effect was more obvious in a medium with magnesium as sole divalent metal ions, while in a medium with magnesium and manganese the addition of copper had a less pronounced effect. Since the malic enzyme was recognised as a supplier of reducing power in the form of reduced nicotinamide adenine dinucleotide phosphate for lipid biosynthesis, its kinetic parameters with regard to different concentrations of metal ions were investigated. Some inhibition was found with Fe(2+) and Zn(2+), while Cu(2+) ions in a concentration of 0.1 mM completely abolished malic enzyme activity. The same metal ions proportionally reduced the levels of total lipids in Aspergillus niger cells. A strong competitive inhibition of the enzyme by Cu(2+) was observed. It seemed that copper competes with Mg(2+) and Mn(2+) for the same binding site on the protein. PMID:12480102

  17. Degradation of phytates in distillers' grains and corn gluten feed by Aspergillus niger phytase.

    PubMed

    Noureddini, H; Dang, J

    2009-10-01

    Distillers' dried grains with solubles (DDGS) and corn gluten feed (CGF) are major coproducts of ethanol production from corn dry grind and wet milling facilities, respectively. These coproducts contain important nutrients and high levels of phytates. The phytates in these products cannot be digested by nonruminant animals; consequently, large quantities of phytate phosphorus (P) are deposited into the soil with the animal wastes which potentially could cause P pollution in soil and underground water resources. To reduce phytates in DDGS and CGF, a phytase from Aspergillus niger, PhyA, was investigated regarding its capability to catalyze the hydrolysis of phytates in light steep water (LSW) and whole stillage (WS). LSW and WS streams are the intermediate streams in the production of CGF and DDGS, respectively, and contribute to most of the P in these streams. Enzyme loadings with activity of 0.1, 1, 2, and 4 FTU/g substrate and temperatures of 35 and 45 degrees C were investigated regarding their influences on the degree of hydrolysis. The analysis of the hydrolyzate suggested to a sequentially degradation of phytates to lower order myo-inositol phosphate isomers. Approximately 90% phytate P of LSW and 66% phytate P of WS were released, suggesting myo-inositol monophosphate as the end product. The maximum amount of released P was 4.52 +/- 0.03 mg/g LSW and 0.86 +/- 0.01 mg/g WS. PMID:18815903

  18. Sorption of heavy metals by the soil fungi 'Aspergillus niger' and Mucor rouxii

    SciTech Connect

    Mullen, M.D.; Wolf, D.C.; Beveridge, T.J.; Bailey, G.W.

    1992-01-01

    Sorption of the nitrate salts of cadmium(II), copper(II), lanthanum(III) and silver(I) by two fungi, Aspergillus niger and Mucor rouxii, was evaluated using Freundlich adsorption isotherms and energy dispersive X-ray electron microscopy. The linearized Freundlich isotherm described the metal sorption data well for metal concentrations of 5 microM-1 mM metal. Differences in metal binding were observed among metals, as well as between fungal species. Calculated Freundlich K values indicated that metal binding decreased in the order La(3+) > or = Ag(+) > Cu(2+) > Cd(2+). However, sorption of Ag(+) was greater than that of La(3+) from solutions of 0.1 and 1 mM metal and likely due to precipitation at the cell wall surface. At the 1 mM initial concentration, there were no significant differences between the two fungi in metal sorption, except for Ag(+) binding. At the 5 microM concentration, there was no difference between the fungi in their sorption capacities for the four metals. Electron microscopy-energy dispersive X-ray analysis indicated that silver precipitated onto cells as colloidal silver. The results indicate that Freundlich isotherms may be useful for describing short-term metal sorption by fungal biomass and for comparison with other soil constituents in standardized systems. (Copyright (c) 1992 Pergamon Press plc.)

  19. Purification and characterization of endo-xylanases from Aspergillus Niger. III. An enzyme of PL 365

    SciTech Connect

    Fournier, R.A.; Frederick, M.M.; Frederick, J.R.; Reilly, P.J.

    1985-04-01

    An endo-xylanase (1,4-..beta..-D-xylan xylanohydrolase, EC 3.2.1.8) from Aspergillus niger was purified to homogeneity by chromatography with Ultrogel AcA 54, SP-Sephadex C-25 at pH 4.5, DEAE-Sephadex A-25 at pH 5.4, Sephadex G-50, and DEAE-Sephadex A-25 at pH 5.15. The enzyme was active on soluble xylan, on insoluble xylan only after arabinosyl-initiated branch points were removed, and on xylooligosaccharides longer than xylotetraose. There was slight activity on carboxymethyl-cellulose, arabinogalactan, glucomannan, and p-nitrophenyl-..beta..-D- glucopyranoside. The main products of the hydrolysis of soluble and insoluble xylan were oligosaccharides of intermediate length, especially the tri- and pentasaccharides. The isolectric point of the enzyme was 3.65. It had a molecular weight of 2.8 x 10/sup 4/ by SDS-gel electrophoresis, and was high in acidic amino acids but low in those containing sulfur. Highest activity in a 20-min assay at pH 5 was between 40 and 45 degrees C, with an activation energy up to 40 degrees C of 11.1 kJ/mol. The optimum pH for activity was at 5.0. The enzyme was strongly activated by Ca/sup 2 +/. 15 references.

  20. Microbial leaching of chromite overburden from Sukinda mines, Orissa, India using Aspergillus niger

    NASA Astrophysics Data System (ADS)

    Biswas, Supratim; Samanta, Saikat; Dey, Rajib; Mukherjee, Siddhartha; Banerjee, Pataki C.

    2013-08-01

    Leaching of nickel and cobalt from two physical grades (S1, 125-190 μm, coarser and S3, 53-75 μm, finer) of chromite overburden was achieved by treating the overburden (2% pulp density) with 21-d culture filtrate of an Aspergillus niger strain grown in sucrose medium. Metal dissolution increases with ore roasting at 600°C and decreasing particle size due to the alteration of microstructural properties involving the conversion of goethite to hematite and the increase in surface area and porosity as evident from X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (DT-TGA), and field emission scanning electron microscopy (FESEM). About 65% Ni and 59% Co were recovered from the roasted S3 ore employing bioleaching against 26.87% Ni and 31.3% Co using an equivalent amount of synthetic oxalic acid under identical conditions. The results suggest that other fungal metabolites in the culture filtrate played a positive role in the bioleaching process, making it an efficient green approach in Ni and Co recovery from lateritic chromite overburden.

  1. Bioleaching of nickel and cobalt from lateritic chromite overburden using the culture filtrate of Aspergillus niger.

    PubMed

    Biswas, Supratim; Dey, Rajib; Mukherjee, Siddhartha; Banerjee, Pataki C

    2013-08-01

    Extraction of metals (Ni, Co) from chromite overburden of Sukinda mines of Orissa, India, with the culture filtrate of Aspergillus niger was studied. Results showed that the amounts of metals leached varied directly with reaction temperature and period of fermentation. The culture filtrate was analyzed for citric and oxalic acids, and contained only oxalic acid-the concentration of which increased with time. Although this acid played the major role in leaching of metals, other unidentified metabolites present in the culture filtrate influenced the dissolution of the metals significantly. Maximum recovery of metals from raw and roasted ore samples was achieved at 80 °C with the 21-day culture filtrate containing the highest amount of oxalic acid. Under identical experimental conditions, much higher amounts of the metals were leached from roasted ore. Microstructures of the ore particles were studied by scanning electron microscopy and transmission electron microscopy; the bonding behaviors of metal compounds were identified by Fourier transform infrared spectroscopy which showed that the metals were leached after chelation with oxalic acid. PMID:23700146

  2. Purification and characterisation of an extracellular phytase from Aspergillus niger 11T53A9

    PubMed Central

    Greiner, Ralf; da Silva, Lucineia Gomes; Couri, Sonia

    2009-01-01

    An extracellular phytase from Aspergillus niger 11T53A9 was purified about 51-fold to apparent homogeneity with a recovery of 20.3% referred to the phytase activity in the crude extract. Purification was achieved by ammonium sulphate precipitation, ion chromataography and gel filtration. The purified enzyme behaved as a monomeric protein with a molecular mass of about 85 kDa and exhibited maximal phytate-degrading activity at pH 5.0. Optimum temperature for the degradation of phytate was 55C. The kinetic parameters for the hydrolysis of sodium phytate were determined to be KM = 54 mol l-1 and kcat = 190 sec-1 at pH 5.0 and 37C. The purified enzyme was rather specific for phytate dephosphorylation. It was shown that the phytase preferably dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,4,5,6)P5, D-Ins(1,2,5,6)P4, D-Ins(1,2,6)P3, D-Ins(1,2)P2 to finally Ins(2)P. PMID:24031427

  3. Transformation of rutin to antiproliferative quercetin-3-glucoside by Aspergillus niger.

    PubMed

    You, Hyun Ju; Ahn, Hyung Jin; Ji, Geun Eog

    2010-10-27

    The flavonol quercetin in plants and foods occurs predominantly in the form of glycoside whose sugar moiety affects the bioavailability and the mechanism of its biological activities. The antiproliferative activities of quercetin derivatives such as quercetin aglycone, quercetin-3-?-D-glucoside (Q3G), and rutin were compared using six different cancer cell lines including colon, breast, hepatocellular, and lung cancer. The IC50 value of Q3G ranged between 15 and 25 ?M in HT-29, HCT 116, MCF-7, HepG2, and A549 cells. In these five cell lines, Q3G showed the most potent growth inhibition, whereas rutin showed the least potency. Transformation of rutin to Q3G was conducted by controlling ?-L-rhamnosidase and ?-D-glucosidase activities from crude enzyme extract of Aspergillus niger. Carbon sources during culture and transformation conditions such as pH, temperature, and heat-stability were optimized. After 4 h biotransformation, 99% of rutin was transformed to Q3G and no quercetin was detected. This study presented an efficient biotransformation for the conversion of rutin to Q3G which was newly shown to have more potent antiproliferative effect than quercetin and rutin. PMID:20886886

  4. Evaluation of free and immobilized Aspergillus niger NRC1ami pectinase applicable in industrial processes.

    PubMed

    Esawy, Mona A; Gamal, Amira A; Kamel, Zeinat; Ismail, Abdel-Mohsen S; Abdel-Fattah, Ahmed F

    2013-02-15

    The Aspergillus niger NRC1ami pectinase was evaluated according to its hydrolysis efficiency of dry untreated orange peels (UOP), HCl-treated orange peels and NaOH-treated orange peels (HOP and NOP). Pectinase was entrapped in polyvinyl alcohol (PVA) sponge and the optimum pH and temperature of the free and immobilized enzymes were shifted from 4, 40 °C to 6, 50 °C respectively. The study of pH stability of free and immobilized pectinase showed that the immobilization process protected the enzyme strongly from severe alkaline pHs. The immobilization process improved the enzyme thermal stability to great instant. The unique feature of the immobilization process is its ability to solve the orange juice haze problem completely. Immobilized enzyme was reused 12 times in orange juice clarification with 9% activity loss from the original activity. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the partially purified form were significantly changed after immobilization. PMID:23399177

  5. Citric acid production from Aspergillus niger MT-4 using hydrolysate extract of the insect Locusta migratoria.

    PubMed

    Taskin, Mesut; Tasar, Gani Erhan; Incekara, Umit

    2013-06-01

    Citric acid (CA) is the most important organic acid used in the food and other industries. Locusta migratoria is an insect species, which has rich nutritional composition (especially protein) and cultivated in some countries. Therefore, the present study investigated the usability of hydrolysate extract of L. migratoria biomass as substrate for the production of CA from Aspergillus niger MT-4. The insect extract (IE) was found to be rich in ash (34.9 g/100 g), protein (35.6 g/100 g) and mineral contents. Yeast extract was found to be the most favorable substrate for biomass production, whereas the maximum production of CA (41.8 g/L) was achieved in the medium containing IE. Besides, uniform pellets with the smallest size (4 mm) were observed in IE medium. It was thought that rich magnesium (6.78 g/100 g) and manganese (1.14 g/100 g) contents of IE increased the production of CA, resulting in the formation of small uniform pellets. This is the first report on the effect of protein-rich insect biomasses on the production of CA. In this regard, L. migratoria biomass was tested for the first time as a CA-production substrate. PMID:22323475

  6. Magnetically recyclable, antimicrobial, and catalytically enhanced polymer-assisted "green" nanosystem-immobilized Aspergillus niger amyloglucosidase.

    PubMed

    Konwarh, Rocktotpal; Kalita, Dipankar; Mahanta, Charulata; Mandal, Manabendra; Karak, Niranjan

    2010-08-01

    The present work reports the integration of polymer matrix-supported nanomaterial and enzyme biotechnology for development of industrially feasible biocatalysts. Aqueous leaf extract of Mesua ferrea L. was used to prepare silver nanoparticles distributed within a narrow size range (1-12 nm). In situ oxidative technique was used to obtain poly(ethylene glycol)-supported iron oxide nanoparticles (3-5 nm). Sonication-mediated mixing of above nanoparticles generated the immobilization system comprising of polymer-supported silver-iron oxide nanoparticles (20-30 nm). A commercially important enzyme, Aspergillus niger amyloglucosidase was coupled onto the immobilization system through sonication. The immobilization enzyme registered a multi-fold increment in the specific activity (807 U/mg) over the free counterpart (69 U/mg). Considerable initial activity of the immobilized enzyme was retained even after storing the system at room temperature as well as post-repeated magnetic recycling. Evaluation of the commendable starch saccharification rate, washing performance synergy with a panel of commercial detergents, and antibacterial potency strongly forwards the immobilized enzyme as a multi-functional industrially feasible system. PMID:20490787

  7. Fluoride-Tolerant Mutants of Aspergillus niger Show Enhanced Phosphate Solubilization Capacity

    PubMed Central

    Silva, Ubiana de Cássia; Mendes, Gilberto de Oliveira; Silva, Nina Morena R. M.; Duarte, Josiane Leal; Silva, Ivo Ribeiro; Tótola, Marcos Rogério; Costa, Maurício Dutra

    2014-01-01

    P-solubilizing microorganisms are a promising alternative for a sustainable use of P against a backdrop of depletion of high-grade rock phosphates (RPs). Nevertheless, toxic elements present in RPs, such as fluorine, can negatively affect microbial solubilization. Thus, this study aimed at selecting Aspergillus niger mutants efficient at P solubilization in the presence of fluoride (F−). The mutants were obtained by exposition of conidia to UV light followed by screening in a medium supplemented with Ca3(PO4)2 and F−. The mutant FS1-555 showed the highest solubilization in the presence of F−, releasing approximately 70% of the P contained in Ca3(PO4)2, a value 1.7 times higher than that obtained for the wild type (WT). The mutant FS1-331 showed improved ability of solubilizing fluorapatites, increasing the solubilization of Araxá, Catalão, and Patos RPs by 1.7, 1.6, and 2.5 times that of the WT, respectively. These mutants also grew better in the presence of F−, indicating that mutagenesis allowed the acquisition of F− tolerance. Higher production of oxalic acid by FS1-331 correlated with its improved capacity for RP solubilization. This mutant represents a significant improvement and possess a high potential for application in solubilization systems with fluoride-rich phosphate sources. PMID:25310310

  8. Hydroxylation of 1,8-cineole by Mucor ramannianus and Aspergillus niger.

    PubMed

    Ramos, Aline de Souza; Ribeiro, Joyce Benzaquem; Teixeira, Bruna Gomes; Ferreira, José Luiz Pinto; Silva, Jefferson Rocha de A; Ferreira, Alexandre do Amaral; de Souza, Rodrigo Octavio Mendonça Alves; Amaral, Ana Claudia F

    2015-03-01

    The monoterpenoid 1,8-cineole is obtained from the leaves of Eucalyptus globulus and it has important biological activities. It is a cheap natural substrate because it is a by-product of the Eucalyptus cultivation for wood and pulp production. In this study, it was evaluated the potential of three filamentous fungi in the biotransformation of 1,8-cineole. The study was divided in two steps: first, reactions were carried out with 1,8-cineole at 1 g/L for 24 h; afterwards, reactions were carried out with substrate at 5 g/L for 5 days. The substrate was hydroxylated into 2-exo-hydroxy-1,8-cineole and 3-exo-hydroxy-1,8-cineole by fungi Mucor ramannianus and Aspergillus niger with high stereoselectivity. Trichoderma harzianum was also tested but no transformation was detected. M. ramannianus led to higher than 99% of conversion within 24 h with a starting high substrate concentration (1 g/L). When substrate was added at 5 g/L, only M. ramannianus was able to catalyze the reaction, but the conversion level was 21.7% after 5 days. Both products have defined stereochemistry and could be used as chiral synthons. Furthermore, biological activity has been described for 3-exo-hydroxy-1,8-cineol. To the best of our knowledge, this is the first report on the use of M. ramannianus in this reaction. PMID:26221115

  9. Hydroxylation of 1,8-cineole by Mucor ramannianus and Aspergillus niger

    PubMed Central

    Ramos, Aline de Souza; Ribeiro, Joyce Benzaquem; Teixeira, Bruna Gomes; Ferreira, José Luiz Pinto; Silva, Jefferson Rocha de A.; Ferreira, Alexandre do Amaral; de Souza, Rodrigo Octavio Mendonça Alves; Amaral, Ana Claudia F.

    2015-01-01

    The monoterpenoid 1,8-cineole is obtained from the leaves of Eucalyptus globulus and it has important biological activities. It is a cheap natural substrate because it is a by-product of the Eucalyptus cultivation for wood and pulp production. In this study, it was evaluated the potential of three filamentous fungi in the biotransformation of 1,8-cineole. The study was divided in two steps: first, reactions were carried out with 1,8-cineole at 1 g/L for 24 h; afterwards, reactions were carried out with substrate at 5 g/L for 5 days. The substrate was hydroxylated into 2-exo-hydroxy-1,8-cineole and 3-exo-hydroxy-1,8-cineole by fungi Mucor ramannianus and Aspergillus niger with high stereoselectivity. Trichoderma harzianum was also tested but no transformation was detected. M. ramannianus led to higher than 99% of conversion within 24 h with a starting high substrate concentration (1 g/L). When substrate was added at 5 g/L, only M. ramannianus was able to catalyze the reaction, but the conversion level was 21.7% after 5 days. Both products have defined stereochemistry and could be used as chiral synthons. Furthermore, biological activity has been described for 3-exo-hydroxy-1,8-cineol. To the best of our knowledge, this is the first report on the use of M. ramannianus in this reaction. PMID:26221115

  10. Expression of an Aspergillus niger xylanase in yeast: Application in breadmaking and in vitro digestion.

    PubMed

    Elgharbi, Fatma; Hmida-Sayari, Ada; Zaafouri, Youssef; Bejar, Samir

    2015-08-01

    The cDNA of the ?-1,4-endoxylanase of Aspergillus niger US368 was cloned and expressed in Pichia pastoris under the constitutive GAP promoter. The maximum activity obtained was 41 U mL(-1), which was about 3-fold higher than that obtained with the native species. The purified enzyme showed a specific activity of 910 U mg(-1) and a molecular mass of 24 kDa. It had an optimal activity at pH 4 and 50 C, stable in a wide range of pH and in the presence of some detergents and organic solvents. r-XAn11-His6 (recombinant xylanase) was used as an additive in breadmaking. A decrease in water absorption, an increase in dough rising and improvements in volume and specific volume of the bread were recorded. The r-XAn11-His6 was also used in in vitro digestion of barley and wheat bran leading to a decrease of the viscosities and an increase of the reducing sugars and total sugars contents. PMID:25936280

  11. Effects of cellulase from Aspergillus niger and solvent pretreatments on the extractability of organic green tea waste.

    PubMed

    Kim, Jae Hun; Pan, Jeong Hoon; Heo, Wan; Lee, Hyungjae; Kwon, Eung Gi; Lee, Hong-Gu; Shin, Dong Hoon; Liu, Rui Hai; Kim, Young Jun

    2010-10-13

    As green tea is being consumed in larger amounts, more green tea waste is being produced. Following extraction, several bioactive compounds may exist in the waste including polyphenols and amino acids. It was found that an Aspergillus niger cellulase treatment of green tea waste increased the extractability of various nutritional and functional components after pretreatments with various extraction solvents such as cold water (CW), hot water (HW), sulfuric acid (SA), hydrochloric acid (HA), and methanol (Me). After the residue was treated with cellulase from Aspergillus niger, the amounts of polyphenols, total catechins, and reducing sugars in the HW extract were increased by 64.6, 941.2, and 350.9%, respectively. In particular, levels of epigallocatechin, epicatechin, and gallic acid were significantly enhanced compared to those in the nontreated control. However, protein extraction was not significantly affected, and cellulase treatment was not more efficient for caffeine extraction compared to phenolic extraction. Among the four extraction solvents, HW and SA showed relatively higher extractabilities as compared to the other groups (CW, HA, and Me). These results indicate that cellulase from A. niger can increase the extractability of green tea waste when combined with certain solvent pretreatments. Consequently, the residual functional compounds and essential nutrients from cellulase-treated green tea waste have the potential to be applied in the production of new functional foods. PMID:20843026

  12. Quantitative proteomics reveals the mechanism and consequence of gliotoxin-mediated dysregulation of the methionine cycle in Aspergillus niger.

    PubMed

    Manzanares-Miralles, Lara; Sarikaya-Bayram, Özlem; Smith, Elizabeth B; Dolan, Stephen K; Bayram, Özgür; Jones, Gary W; Doyle, Sean

    2016-01-10

    Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus, which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p=0.0018) required for homocysteine generation from S-adenosylhomocysteine (SAH), and spermidine synthase (p=0.0068), involved in the recycling of Met, was observed. Analysis of Met-related metabolites revealed significant increases in the levels of Met and adenosine, in correlation with proteomic data. Methyltransferase MT-II is responsible for bisthiobis(methylthio)gliotoxin (BmGT) formation, deletion of MT-II abolished BmGT formation and led to increased GT sensitivity in A. niger. Proteomic analysis also revealed that GT exposure also significantly (p<0.05) increased hydrolytic enzyme abundance, including glycoside hydrolases (n=22) and peptidases (n=16). We reveal that in an attempt to protect against the detrimental affects of GT, methyltransferase-mediated GT thiomethylation alters cellular pathways involving Met and SAM, with consequential dysregulation of hydrolytic enzyme abundance in A. niger. Thus, it provides new opportunities to exploit the response of GT-naïve fungi to GT. PMID:26498071

  13. Utilization of molasses and sugar cane bagasse for production of fungal invertase in solid state fermentation using Aspergillus niger GH1.

    PubMed

    Veana, F; Martnez-Hernndez, J L; Aguilar, C N; Rodrguez-Herrera, R; Michelena, G

    2014-01-01

    Agro-industrial wastes have been used as substrate-support in solid state fermentation for enzyme production. Molasses and sugarcane bagasse are by-products of sugar industry and can be employed as substrates for invertase production. Invertase is an important enzyme for sweeteners development. In this study, a xerophilic fungus Aspergillus niger GH1 isolated of the Mexican semi-desert, previously reported as an invertase over-producer strain was used. Molasses from Mexico and Cuba were chemically analyzed (total and reducer sugars, nitrogen and phosphorous contents); the last one was selected based on chemical composition. Fermentations were performed using virgin and hydrolyzate bagasse (treatment with concentrated sulfuric acid). Results indicated that, the enzymatic yield (5231 U/L) is higher than those reported by other A. niger strains under solid state fermentation, using hydrolyzate bagasse. The acid hydrolysis promotes availability of fermentable sugars. In addition, maximum invertase activity was detected at 24 h using low substrate concentration, which may reduce production costs. This study presents an alternative method for invertase production using a xerophilic fungus isolated from Mexican semi-desert and inexpensive substrates (molasses and sugarcane bagasse). PMID:25242918

  14. Utilization of molasses and sugar cane bagasse for production of fungal invertase in solid state fermentation using Aspergillus niger GH1

    PubMed Central

    Veana, F.; Martnez-Hernndez, J.L.; Aguilar, C.N.; Rodrguez-Herrera, R.; Michelena, G.

    2014-01-01

    Agro-industrial wastes have been used as substrate-support in solid state fermentation for enzyme production. Molasses and sugarcane bagasse are by-products of sugar industry and can be employed as substrates for invertase production. Invertase is an important enzyme for sweeteners development. In this study, a xerophilic fungus Aspergillus niger GH1 isolated of the Mexican semi-desert, previously reported as an invertase over-producer strain was used. Molasses from Mexico and Cuba were chemically analyzed (total and reducer sugars, nitrogen and phosphorous contents); the last one was selected based on chemical composition. Fermentations were performed using virgin and hydrolyzate bagasse (treatment with concentrated sulfuric acid). Results indicated that, the enzymatic yield (5231 U/L) is higher than those reported by other A. niger strains under solid state fermentation, using hydrolyzate bagasse. The acid hydrolysis promotes availability of fermentable sugars. In addition, maximum invertase activity was detected at 24 h using low substrate concentration, which may reduce production costs. This study presents an alternative method for invertase production using a xerophilic fungus isolated from Mexican semi-desert and inexpensive substrates (molasses and sugarcane bagasse). PMID:25242918

  15. Genomic analysis of the secretion stress response in the enzyme-producing cell factory Aspergillus niger

    PubMed Central

    Guillemette, Thomas; van Peij, Noël NME; Goosen, Theo; Lanthaler, Karin; Robson, Geoffrey D; van den Hondel, Cees AMJJ; Stam, Hein; Archer, David B

    2007-01-01

    Background Filamentous fungi such as Aspergillus niger have a high capacity secretory system and are therefore widely exploited for the industrial production of native and heterologous proteins. However, in most cases the yields of non-fungal proteins are significantly lower than those obtained for fungal proteins. One well-studied bottleneck appears to be the result of mis-folding of heterologous proteins in the ER during early stages of secretion, with related stress responses in the host, including the unfolded protein response (UPR). This study aims at uncovering transcriptional and translational responses occurring in A. niger exposed to secretion stress. Results A genome-wide transcriptional analysis of protein secretion-related stress responses was determined using Affymetrix DNA GeneChips and independent verification for selected genes. Endoplasmic reticulum (ER)-associated stress was induced either by chemical treatment of the wild-type cells with dithiothreitol (DTT) or tunicamycin, or by expressing a human protein, tissue plasminogen activator (t-PA). All of these treatments triggered the UPR, as shown by the expression levels of several well-known UPR target genes. The predicted proteins encoded by most of the up-regulated genes function as part of the secretory system including chaperones, foldases, glycosylation enzymes, vesicle transport proteins, and ER-associated degradation proteins. Several genes were down-regulated under stress conditions and these included several genes that encode secreted enzymes. Moreover, translational regulation under ER stress was investigated by polysomal fractionation. This analysis confirmed the post-transcriptional control of hacA expression and highlighted that differential translation also occurs during ER stress, in particular for some genes encoding secreted proteins or proteins involved in ribosomal biogenesis and assembly. Conclusion This is first genome-wide analysis of both transcriptional and translational events following protein secretion stress. Insight has been gained into the molecular basis of protein secretion and secretion-related stress in an effective protein-secreting fungus, and provides an opportunity to identify target genes for manipulation in strain improvement strategies. PMID:17561995

  16. Aspergillus pragensis sp. nov. discovered during molecular reidentification of clinical isolates belonging to Aspergillus section Candidi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The identity of nine clinical isolates from Czech patients presumably belonging to Aspergillus section Candidi based on morphology of colonies was revised using sequences of -tubulin, calmodulin, and internal transcribed spacer (ITS) rDNA. The set of isolates included six isolates from suspected (n...

  17. Highly thermostable and pH-stable cellulases from Aspergillus niger NS-2: properties and application for cellulose hydrolysis.

    PubMed

    Bansal, Namita; Janveja, Chetna; Tewari, Rupinder; Soni, Raman; Soni, Sanjeev Kumar

    2014-01-01

    Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 20.1 U/g, FPase 101.1 3.5 U/g and ?-glucosidase 99 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 C, the half life for CMCase, FPase, ?-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %. PMID:24052336

  18. A new group of exo-acting family 28 glycoside hydrolases of Aspergillus niger that are involved in pectin degradation

    PubMed Central

    Martens-Uzunova, ElenaS.; Zandleven, JorisS.; Benen, JaquesA.E.; Awad, Hanem; Kools, HarrieJ.; Beldman, Gerrit; Voragen, AlphonsG.J.; Van Den Berg, JohanA.; Schaap, PeterJ.

    2006-01-01

    The fungus Aspergillus niger is an industrial producer of pectin-degrading enzymes. The recent solving of the genomic sequence of A. niger allowed an inventory of the entire genome of the fungus for potential carbohydrate-degrading enzymes. By applying bioinformatics tools, 12 new genes, putatively encoding family 28 glycoside hydrolases, were identified. Seven of the newly discovered genes form a new gene group, which we show to encode exoacting pectinolytic glycoside hydrolases. This group includes four exo-polygalacturonan hydrolases (PGAX, PGXA, PGXB and PGXC) and three putative exo-rhamnogalacturonan hydrolases (RGXA, RGXB and RGXC). Biochemical identification using polygalacturonic acid and xylogalacturonan as substrates demonstrated that indeed PGXB and PGXC act as exo-polygalacturonases, whereas PGXA acts as an exo-xylogalacturonan hydrolase. The expression levels of all 21 genes were assessed by microarray analysis. The results from the present study demonstrate that exo-acting glycoside hydrolases play a prominent role in pectin degradation. PMID:16822232

  19. Replacement P212H altered the pH-temperature profile of phytase from Aspergillus niger NII 08121.

    PubMed

    Ushasree, Mrudula Vasudevan; Vidya, Jalaja; Pandey, Ashok

    2015-03-01

    Microbial phytase, a widely used animal feed enzyme, needs to be active and stable in the acidic milieu for better performance in the monogastric gut. Aspergillus niger phytases exhibit an activity dip in the pH range from 3.0 to 3.5. Replacement of amino acids, which changed the pKa of catalytic residues H82 and D362, resulted in alteration of the pH profile of a thermostable phytase from A. niger NII 08121. Substitution P212H in the protein loop at 14 distance to the active site amended the pH optimum from 2.5 to pH3.2 nevertheless with a decrease in thermostability than the wild enzyme. This study described the utility of amino acid replacements based on pKa shifts of catalytic acid/base to modulate the pH profile of phytases. PMID:25595493

  20. Bioconversion of waste office paper to gluconic acid in a turbine blade reactor by the filamentous fungus Aspergillus niger.

    PubMed

    Ikeda, Yuko; Park, Enock Y; Okuda, Naoyuki

    2006-05-01

    Gluconic acid production was investigated using an enzymatic hydrolysate of waste office automation paper in a culture of Aspergillus niger. In repeated batch cultures using flasks, saccharified solution medium (SM) did not show any inhibitory effects on gluconic acid production compared to glucose medium (GM). The average gluconic acid yields were 92% (SM) and 80% (GM). In repeated batch cultures using SM in a turbine blade reactor (TBR), the gluconic acid yields were 60% (SM) and 67% (GM) with 80-100 g/l of gluconic acid. When pure oxygen was supplied the production rate increased to four times higher than when supplying air. Remarkable differences in the morphology of A. niger and dry cell weight between SM and GM were observed. The difference in morphology may have caused a reduction of oxygen transfer, resulting in a decrease in gluconic acid production rate in SM. PMID:15979872

  1. Production of the Phanerochaete flavido-alba laccase in Aspergillus niger for synthetic dyes decolorization and biotransformation.

    PubMed

    Benghazi, Lamiae; Record, Eric; Surez, Antonio; Gomez-Vidal, Jos A; Martnez, Jos; de la Rubia, Teresa

    2014-01-01

    We investigated the expression of Phanerochaete flavido-alba laccase gene in Aspergillus niger and the physical and biochemical properties of the recombinant enzyme (rLac-LPFA) in order to test it for synthetic dye biotransformation. A. niger was able to produce high levels of active recombinant enzyme (30mgL(-1)), whose identity was further confirmed by immunodetection using Western blot analysis and N-terminal sequencing. Interestingly, rLac-LPFA exhibited an improved stability at pH (2-9) and organic solvents tested. Furthermore, the percentage of decoloration and biotransformation of synthetic textile dyes, Remazol Brilliant Blue R (RBBR) and Acid Red 299 (NY1), was higher than for the native enzyme. Its high production, simple purification, high activity, stability and ability to transform textile dyes make rLac-LPFA a good candidate for industrial applications. PMID:23884844

  2. Protein kinase A signaling and calcium ions are major players in PAF mediated toxicity against Aspergillus niger

    PubMed Central

    Binder, Ulrike; Ben?ina, Mojca; Fizil, dm; Batta, Gyula; Chhillar, Anil K.; Marx, Florentine

    2015-01-01

    The Penicillium chrysogenum antifungal protein PAF is toxic against potentially pathogenic Ascomycetes. We used the highly sensitive aequorin-expressing model Aspergillus niger to identify a defined change in cytoplasmic free Ca2+ dynamics in response to PAF. This Ca2+ signature depended on an intact positively charged lysine-rich PAF motif. By combining Ca2+ measurements in A. niger mutants with deregulated cAMP/protein kinase A (PKA) signaling, we proved the interconnection of Ca2+ perturbation and cAMP/PKA signaling in the mechanistic function of PAF. A deep understanding of the mode of action of PAF is an invaluable prerequisite for its future application as new antifungal drug. PMID:25882631

  3. Mixed Disulfide Formation at Cys141 Leads to Apparent Unidirectional Attenuation of Aspergillus niger NADP-Glutamate Dehydrogenase Activity

    PubMed Central

    Walvekar, Adhish S.; Choudhury, Rajarshi; Punekar, Narayan S.

    2014-01-01

    NADP-Glutamate dehydrogenase from Aspergillus niger (AnGDH) exhibits sigmoid 2-oxoglutarate saturation. Incubation with 2-hydroxyethyl disulfide (2-HED, the disulfide of 2-mercaptoethanol) resulted in preferential attenuation of AnGDH reductive amination (forward) activity but with a negligible effect on oxidative deamination (reverse) activity, when monitored in the described standard assay. Such a disulfide modified AnGDH displaying less than 1.0% forward reaction rate could be isolated after 2-HED treatment. This unique forward inhibited GDH form (FIGDH), resembling a hypothetical one-way active enzyme, was characterized. Kinetics of 2-HED mediated inhibition and protein thiol titrations suggested that a single thiol group is modified in FIGDH. Two site-directed cysteine mutants, C141S and C415S, were constructed to identify the relevant thiol in FIGDH. The forward activity of C141S alone was insensitive to 2-HED, implicating Cys141 in FIGDH formation. It was observed that FIGDH displayed maximal reaction rate only after a pre-incubation with 2-oxoglutarate and NADPH. In addition, compared to the native enzyme, FIGDH showed a four fold increase in K0.5 for 2-oxoglutarate and a two fold increase in the Michaelis constants for ammonium and NADPH. With no change in the GDH reaction equilibrium constant, the FIGDH catalyzed rate of approach to equilibrium from reductive amination side was sluggish. Altered kinetic properties of FIGDH at least partly account for the observed apparent loss of forward activity when monitored under defined assay conditions. In sum, although Cys141 is catalytically not essential, its covalent modification provides a striking example of converting the biosynthetic AnGDH into a catabolic enzyme. PMID:24987966

  4. The carbon starvation response of Aspergillus niger during submerged cultivation: Insights from the transcriptome and secretome

    PubMed Central

    2012-01-01

    Background Filamentous fungi are confronted with changes and limitations of their carbon source during growth in their natural habitats and during industrial applications. To survive life-threatening starvation conditions, carbon from endogenous resources becomes mobilized to fuel maintenance and self-propagation. Key to understand the underlying cellular processes is the system-wide analysis of fungal starvation responses in a temporal and spatial resolution. The knowledge deduced is important for the development of optimized industrial production processes. Results This study describes the physiological, morphological and genome-wide transcriptional changes caused by prolonged carbon starvation during submerged batch cultivation of the filamentous fungus Aspergillus niger. Bioreactor cultivation supported highly reproducible growth conditions and monitoring of physiological parameters. Changes in hyphal growth and morphology were analyzed at distinct cultivation phases using automated image analysis. The Affymetrix GeneChip platform was used to establish genome-wide transcriptional profiles for three selected time points during prolonged carbon starvation. Compared to the exponential growth transcriptome, about 50% (7,292) of all genes displayed differential gene expression during at least one of the starvation time points. Enrichment analysis of Gene Ontology, Pfam domain and KEGG pathway annotations uncovered autophagy and asexual reproduction as major global transcriptional trends. Induced transcription of genes encoding hydrolytic enzymes was accompanied by increased secretion of hydrolases including chitinases, glucanases, proteases and phospholipases as identified by mass spectrometry. Conclusions This study is the first system-wide analysis of the carbon starvation response in a filamentous fungus. Morphological, transcriptomic and secretomic analyses identified key events important for fungal survival and their chronology. The dataset obtained forms a comprehensive framework for further elucidation of the interrelation and interplay of the individual cellular events involved. PMID:22873931

  5. Germination of conidia of Aspergillus niger is accompanied by major changes in RNA profiles

    PubMed Central

    van Leeuwen, M.R.; Krijgsheld, P.; Bleichrodt, R.; Menke, H.; Stam, H.; Stark, J.; Wösten, H.A.B.; Dijksterhuis, J.

    2013-01-01

    The transcriptome of conidia of Aspergillus niger was analysed during the first 8 h of germination. Dormant conidia started to grow isotropically two h after inoculation in liquid medium. Isotropic growth changed to polarised growth after 6 h, which coincided with one round of mitosis. Dormant conidia contained transcripts from 4 626 genes. The number of genes with transcripts decreased to 3 557 after 2 h of germination, after which an increase was observed with 4 780 expressed genes 8 h after inoculation. The RNA composition of dormant conidia was substantially different than all the subsequent stages of germination. The correlation coefficient between the RNA profiles of 0 h and 8 h was 0.46. They were between 0.76–0.93 when profiles of 2, 4 and 6 h were compared with that of 8 h. Dormant conidia were characterised by high levels of transcripts of genes involved in the formation of protecting components such as trehalose, mannitol, protective proteins (e.g. heat shock proteins and catalase). Transcripts belonging to the Functional Gene Categories (FunCat) protein synthesis, cell cycle and DNA processing and respiration were over-represented in the up-regulated genes at 2 h, whereas metabolism and cell cycle and DNA processing were over-represented in the up-regulated genes at 4 h. At 6 h and 8 h no functional gene classes were over- or under-represented in the differentially expressed genes. Taken together, it is concluded that the transcriptome of conidia changes dramatically during the first two h and that initiation of protein synthesis and respiration are important during early stages of germination. PMID:23449598

  6. Citric acid production using immobilized conidia of Aspergillus niger TMB 2022

    SciTech Connect

    Tsay, S.S.; To, K.Y.

    1987-02-20

    Conidia of Aspergillus niger TMB 2022 were immobilized in calcium alginate for the production of citric acid. A 1-ml condidia suspension containing ca. 2.32 x 10/sup 8/ conidia were entrapped into sodium alginate solution in order to prepare 3% Ca-alginate (w/v) gel bead. Immobilized conidia were inoculated into productive medium containing 14% sucrose, 0.25% (NH/sub 4/)/sub 2/CO/sub 3/, 0.25% KH/sub 2/PO/sub 4/, and 0.025% MgSO/sub 4/.7H/sub 2/O with addition of 0.06 mg/l CuSO/sub 4/.5H/sub 2/O, 0.25 mg/l ZnCl/sub 2/, 1.3 mg/l FeCl/sub 3/.6H/sub 2/O, pH 3.8, and incubated at 35 degrees C for 13 days by surface culture to produce 61.53 g/l anhydrous citric acid. Under the same conditions with a batchwise culture, it was found that immobilized conidia could maintain a longer period for citric acid production (31 days): over 70 g/l anhydrous citric acid from runs No. 2-4, with the maximum yield for anhydrous citric acid reaching 77.02 g/l for run No. 2. In contrast, free conidia maintained a shorter acid-producing phase, circa 17 days; the maximum yield for anhydrous citric acid was 71.07 g/l for run No. 2 but dropped quickly as the run number increased. 14 references.

  7. Purification and characterization of endo-xylanases from aspergillus Niger. II. An enzyme of PL 45

    SciTech Connect

    Shei, J.C.; Fratzke, A.R.; Frederick, M.M.; Frederick, J.R.; Reilly, P.J.

    1985-04-01

    A homogeneous endo-xylanase (1,4-..beta..-D-xylan xylano-hydrolase, EC 3.2.1.8) was obtained from a crude Aspergillus niger pentosanase by chromatography with Ultrogel AcA 54, SP-Sephadex C-25 at pH 4.5, DEAE-Sephadex A-25 at pH 5.4, Sephadex G-50, and SP-Sephadex C-25 with a gradient from pH 2.8 to pH 4.6. It was much more active on soluble than on insoluble xylan yielding large amounts of unreacted xylan and a mixture of oligosaccharides with chain lengths from two to six. No xylose or L-arabinose was produced. There was high activity on a xylopentaose through xylononaose mixture, but not on xylobiose, xylotriose, or xylotetraose. The enzyme had slight activity on untreated cellulose, carboxymethylcellulose, and pectin. Molecular weight was ca. 1.4 x 10/sup 4/, with an isoelectric point of 4.5 and an amino acid profile high in acidic but low in sulfur-containing residues. In a 25-min assay at pH 4.7, this endo-xylanase was most active at 45 degrees C, with an activation energy from 5 to 35 degrees C of 33.3 kJ/mol. The optimum pH for activity was 4.9. Decay in buffer was first order, with an activation energy at pH 4.7 from 48 to 53 degrees C of 460 kJ/mol. Optimum pH for stability was about 5.6, where the half-life at 48 degrees C in buffer was ca. 40 h.

  8. Purification and physicochemical properties of polygalacturonase from Aspergillus niger MTCC 3323.

    PubMed

    Kant, Shashi; Vohra, Anuja; Gupta, Reena

    2013-01-01

    Polygalacturonases are the pectinolytic enzymes that catalyze the hydrolytic cleavage of the polygalacturonic acid chain. In the present study, polygalacturonase from Aspergillus niger (MTCC 3323) was purified. The enzyme precipitated with 60% ethanol resulted in 1.68-fold purification. The enzyme was purified to 6.52-fold by Sephacryl S-200 gel-filtration chromatography. On SDS-PAGE analysis, enzyme was found to be a heterodimer of 34 and 69 kDa subunit. Homogeneity of the enzyme was checked by NATIVE-PAGE and its molecular weight was found to be 106 kDa. The purified enzyme showed maximum activity in the presence of polygalacturonic acid at temperature of 45 C, pH of 4.8, reaction time of 15 min. The enzyme was stable within the pH range of 4.0-5.5 for 1 h. At 4 C it retained 50% activity after 108 h but at room temperature it lost its 50% activity after 3h. The addition of Mn(2+), K(+), Zn(2+), Ca(2+) and Al(3+) inhibited the enzyme activity; it increased in the presence of Mg(2+) and Cu(2+) ions. Enzyme activity was increased on increasing the substrate concentration from 0.1% to 0.5%. The K(m) and V(max) values of the enzyme were found to be 0.083 mg/ml and 18.21 ?mol/ml/min. The enzyme was used for guava juice extraction and clarification. The recovery of juice of enzymatically treated pulp increased from 6% to 23%. Addition of purified enzyme increased the %T(650) from 2.5 to 20.4 and Brix from 1.9 to 4.8. The pH of the enzyme treated juice decreased from 4.5 to 3.02. PMID:23069766

  9. Cloning, expression and characterization of β-xylosidase from Aspergillus niger ASKU28.

    PubMed

    Choengpanya, Khuanjarat; Arthornthurasuk, Siriphan; Wattana-amorn, Pakorn; Huang, Wan-Ting; Plengmuankhae, Wandee; Li, Yaw-Kuen; Kongsaeree, Prachumporn T

    2015-11-01

    β-Xylosidases catalyze the breakdown of β-1,4-xylooligosaccharides, which are produced from degradation of xylan by xylanases, to fermentable xylose. Due to their important role in xylan degradation, there is an interest in using these enzymes in biofuel production from lignocellulosic biomass. In this study, the coding sequence of a glycoside hydrolase family 3 β-xylosidase from Aspergillus niger ASKU28 (AnBX) was cloned and expressed in Pichia pastoris as an N-terminal fusion protein with the α-mating factor signal sequence (α-MF) and a poly-histidine tag. The expression level was increased to 5.7 g/l in a fermenter system as a result of optimization of only five codons near the 5' end of the α-MF sequence. The recombinant AnBX was purified to homogeneity through a single-step Phenyl Sepharose chromatography. The enzyme exhibited an optimal activity at 70°C and at pH 4.0-4.5, and a very high kinetic efficiency toward a xyloside substrate. AnBX demonstrated an exo-type activity with retention of the β-configuration, and a synergistic action with xylanase in hydrolysis of beechwood xylan. This study provides comprehensive data on characterization of a glycoside hydrolase family 3 β-xylosidase that have not been determined in any prior investigations. Our results suggested that AnBX may be useful for degradation of lignocellulosic biomass in bioethanol production, pulp bleaching process and beverage industry. PMID:26166179

  10. Analysis of regulation of pentose utilisation in Aspergillus niger reveals evolutionary adaptations in Eurotiales

    PubMed Central

    Battaglia, E.; Visser, L.; Nijssen, A.; van Veluw, G.J.; Wsten, H.A.B.; de Vries, R.P.

    2011-01-01

    Aspergilli are commonly found in soil and on decaying plant material. D-xylose and L-arabinose are highly abundant components of plant biomass. They are released from polysaccharides by fungi using a set of extracellular enzymes and subsequently converted intracellularly through the pentose catabolic pathway (PCP). In this study, the L-arabinose responsive transcriptional activator (AraR) is identified in Aspergillus niger and was shown to control the L-arabinose catabolic pathway as well as expression of genes encoding extracellular L-arabinose releasing enzymes. AraR interacts with the D-xylose-responsive transcriptional activator XlnR in the regulation of the pentose catabolic pathway, but not with respect to release of L-arabinose and D-xylose. AraR was only identified in the Eurotiales, more specifically in the family Trichocomaceae and appears to have originated from a gene duplication event (from XlnR) after this order or family split from the other filamentous ascomycetes. XlnR is present in all filamentous ascomycetes with the exception of members of the Onygenales. Since the Onygenales and Eurotiales are both part of the subclass Eurotiomycetidae, this indicates that strong adaptation of the regulation of pentose utilisation has occurred at this evolutionary node. In Eurotiales a unique two-component regulatory system for pentose release and metabolism has evolved, while the regulatory system was lost in the Onygenales. The observed evolutionary changes (in Eurotiomycetidae) mainly affect the regulatory system as in contrast, homologues for most genes of the L-arabinose/D-xylose catabolic pathway are present in all the filamentous fungi, irrespective of the presence of XlnR and/or AraR. PMID:21892241

  11. Combinatorial approach of statistical optimization and mutagenesis for improved production of acidic phytase by Aspergillus niger NCIM 563 under submerged fermentation condition.

    PubMed

    Bhavsar, K; Gujar, P; Shah, P; Kumar, V Ravi; Khire, J M

    2013-01-01

    Combination of statistical optimization and mutagenesis to isolate hypersecretory strains is studied to maximize phytase production from Aspergillus niger NCIM 563 under submerged fermentation. The overall results obtained show a remarkable 5.98-fold improvement in phytase production rates when compared to that using basal medium. Optimization of culture conditions from parent strain is studied first by the Plackett-Burman technique to evaluate the effects of 11 variables for phytase production. The results showed that glucose, MgSO(4), KCl, incubation period, and MnSO(4) are the most significant variables affecting enzyme production. Further optimization in these variables, using a central composite design technique, resulted in 3.74-fold increase in the yield of phytase production to 254,500 U/l when compared with the activity observed with basal media (68,000 U/l) in shake flask. Our experiments show that the phytase from A. niger NCIM 563 exhibits desirable activity in simulated gastric fluid conditions with low pH and also improved thermostability when compared to commercial phytase. The improved yield demonstrates the potential applicability of phytase enzyme as a source of phytase supplement for phosphorus nutrition and environmental protection in animal feed industry. Physical and chemical mutagenesis experiments were carried out in parallel to isolate hypersecretory mutants that could possibly further enhance the enzyme production. Using optimized media conditions of the parent strain, our results show that mutant strain A. niger NCIM 1359 increased the phytase activity by another 1.6-fold to 407,200 U/l. PMID:22382169

  12. Comparison of glucose oxidases from Penicillium adametzii, Penicillium Funiculosum and Aspergillus Niger in the design of amperometric glucose biosensors.

    PubMed

    Ramanavicius, Arunas; Voronovic, Jaroslav; Semashko, Tatiana; Mikhailova, Raisa; Kausaite-Minkstimiene, Asta; Ramanaviciene, Almira

    2014-01-01

    The properties of amperometric glucose biosensors based on three different glucose oxidases and various redox mediators were evaluated. Glucose oxidases (GOx) from Penicillium adametzii, Penicillium funiculosum and Aspergillus niger and artificial redox mediators, such as ferrocene, ferrocenecarboxaldehyde, ?-methylferrocene methanol and ferrocenecarboxylic acid, were used for modifying the graphite rod electrode and amperometrical reagent-less glucose detection. The obtained results were compared using N-methylphenazonium methyl sulphate in the solution. Taking into account the experimental kinetic parameters and the stability of the tested enzymatic electrodes, GOx from Penicillium funiculosum proved to be more suitable for glucose biosensor design in comparison with other evaluated enzymes. PMID:25492463

  13. Inhibition of citric acid accumulation by manganese ions in Aspergillus niger mutants with reduced citrate control of phosphofructokinase

    SciTech Connect

    Schreferl, G.; Kubicek, C.P.; Roehr, M.

    1986-03-01

    Mutant strains of Aspergillus niger with reduced citrate control of carbohydrate catabolism (cic mutants) grow faster than the parent strain on media containing 5% (wt/vol) citrate. The mutants tolerated a higher intracellular citrate concentration than the parent strain. One mutant (cic-7/3) contained phosphofructokinase activity significantly less sensitive towards citrate than the enzyme from the parent strain. When this mutant was grown under citrate accumulating conditions, acidogenesis was far less sensitive to inhibition by Mn/sup 2 +/ than in the parent strain. Some of the cic mutants also showed altered citrate inhibition of NADP-specific isocitrate dehydrogenase.

  14. Thermal stability of Trichoderma reesei C30 cellulase and Aspergillus niger. beta. -glucosidase after pH and chemical modification

    SciTech Connect

    Woodward, J.; Whaley, K.S.; Zachry, G.S.; Wohlpart, D.L.

    1981-01-01

    Treatment of Trichoderma reesei C30 cellulase at pH 10.0 for 1 h at room temperature increased its pH and thermal stability. Chemical modification of the free epsilon-amino groups of cellulase at pH 10.0 resulted in no further increase in stability. Such chemical modification, however, decreased the thermal stability of the cellulose-cellulase complex. On the contrary, the chemical modification of Aspergillus niger ..beta..-glucosidase with glutaraldehyde at pH 8.0 increased the thermal stability of this enzyme.

  15. Thermal stability of Trichoderma reesei c30 cellulase and aspergillus niger; -glucosidase after ph and chemical modification

    SciTech Connect

    Woodward, J.; Whaley, K.S.; Zachry, G.S.; Wohlpart, D.L.

    1981-01-01

    Treatment of Trichoderma reesei C30 cellulase at pH 10.0 for 1 h at room temperature increased its pH and thermal stability. Chemical modification of the free epsilon-amino groups of cellulase at pH 10.0 resulted in no further increase in stability. Such chemical modification, however, decreased the thermal stability of the cellulose-cellulase complex. On the contrary, the chemical modification of Aspergillus niger glucosidase with glutaraldehyde at pH 8.0 increased the thermal stability of this enzyme.

  16. Effect of temperature, water activity, and pH on growth and production of ochratoxin A by Aspergillus niger and Aspergillus carbonarius from Brazilian grapes.

    PubMed

    Passamani, Fabiana Reinis Franca; Hernandes, Thais; Lopes, Noelly Alves; Bastos, Sabrina Carvalho; Santiago, Wilder Douglas; Cardoso, Maria das Graas; Batista, Lus Roberto

    2014-11-01

    The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 ?g/g and 7.0 ?g/g, respectively) were found at 15C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes. PMID:25364929

  17. [Evaluation of the antimicrobial action of honey against Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, Salmonella enteritidis, Listeria monocytogenes and Aspergillus niger. Evaluation of its microbiological charge].

    PubMed

    Estrada, Heylin; Gamboa, María del Mar; Arias, Maria Laura; Chaves, Carolina

    2005-06-01

    The evaluation of the microbiological charge present in Costa Rican samples as the evaluation of its antimicrobial activity over different microorganisms, including those associated to wound infections, will allow to emit criteria referred to its use in therapeutic treatments, specially as alternative therapy for cases involving antibiotic resistant bacteria. The microbiological charge of 25 honey samples, acquired in Costa Rican markets was evaluated through several indicators including total plate aerobic count, total plate anaerobic count, total aerobic spore count, total anaerobic spore count and molds and yeast count. Also, samples were inoculated in tubes with chopped meat media and plated in egg yolk agar in order to determine the presence of Clostridium botulinum. For the antimicrobial activity evaluation, the diffusion method in Muller Hinton agar was performed, testing different honey concentrations (100, 75, 50, 25, 12,5 and 6,25 % v/v) against Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (UCR 2902), Pseudomonas aeruginosa (ATCC 9027), Escherichia coli (ATCC25922), Salmonella enteritidis (ATCC 13076), Listeria monocytogenes (ATCC 19116) and Aspergillus niger. The results obtained for the microbiological characterization of honey show that 91% of samples had counts equal or lower than 1,0 x 10(1) CFU/g. No positive result was obtained for the isolation of C. botulinum. 24 of the samples analyzed inhibited the growth of S. aureus even in a 25% v/v concentration, nevertheless, A. niger was no inhibited by any of the samples tested. PMID:16335227

  18. Production and Optimization of Cellulase Enzyme Using Aspergillus niger USM AI 1 and Comparison with Trichoderma reesei via Solid State Fermentation System.

    PubMed

    Lee, C K; Darah, I; Ibrahim, C O

    2011-01-01

    Novel design solid state bioreactor, FERMSOSTAT, had been evaluated in cellulase production studies using local isolate Aspergillus niger USM AI 1 grown on sugarcane bagasse and palm kernel cake at 1 : 1 (w/w) ratio. Under optimised SSF conditions of 0.5 kg substrate; 70% (w/w) moisture content; 30°C; aeration at 4 L/h · g fermented substrate for 5 min and mixing at 0.5 rpm for 5 min, about 3.4 U/g of Filter paper activity (FPase) was obtained. At the same time, comparative studies of the enzymes production under the same SSF conditions indicated that FPase produced by A. niger USM AI 1 was about 35.3% higher compared to Trichoderma reesei. This shows that the performance of this newly designed SSF bioreactor is acceptable and potentially used as prototype for larger-scale bioreactor design. PMID:21350665

  19. Effect of agitation speed on the morphology of Aspergillus niger HFD5A-1 hyphae and its pectinase production in submerged fermentation

    PubMed Central

    Ibrahim, Darah; Weloosamy, Haritharan; Lim, Sheh-Hong

    2015-01-01

    AIM: To investigate the impact of agitation speed on pectinase production and morphological changing of Aspergillus niger (A. niger) HFD5A-1 in submerged fermentation. METHODS: A. niger HFM5A-1 was isolated from a rotted pomelo. The inoculum preparation was performed by adding 5.0 mL of sterile distilled water containing 0.1% Tween 80 to a sporulated culture. Cultivation was carried out with inoculated 1 107 spores/mL suspension and incubated at 30?C with different agitation speed for 6 d. The samples were withdrawn after 6 d cultivation time and were assayed for pectinase activity and fungal growth determination. The culture broth was filtered through filter paper (Whatman No. 1, London) to separate the fungal mycelium. The cell-free culture filtrate containing the crude enzyme was then assayed for pectinase activity. The biomass was dried at 80?C until constant weight. The fungal cell dry weight was then expressed as g/L. The 6 d old fungal mycelia were harvested from various agitation speed, 0, 50, 100, 150, 200 and 250 rpm. The morphological changing of samples was then viewed under the light microscope and scanning electron microscope. RESULTS: In the present study, agitation speed was found to influence pectinase production in a batch cultivation system. However, higher agitation speeds than the optimal speed (150 rpm) reduced pectinase production which due to shear forces and also collision among the suspended fungal cells in the cultivation medium. Enzyme activity increased with the increasing of agitation speed up to 150 rpm, where it achieved its maximal pectinase activity of 1.559 U/mL. There were significant different (Duncan, P < 0.05) of the pectinase production with the agitation speed at static, 50, 100, 200 and 250 rpm. At the static condition, a well growth mycelial mat was observed on the surface of the cultivation medium and sporulation occurred all over the fungal mycelial mat. However with the increased in agitation speed, the mycelial mat turned slowly to become a single circular pellet. Thus, it was found that agitation speed affected the morphological characteristics of the fungal hyphae/mycelia of A. niger HFD5A-1 by altering their external as well as internal cell structures. CONCLUSION: Exposure to higher shear stress with an increasing agitation speed could result in lower biomass yields as well as pectinase production by A. niger HFD5A-1. PMID:26322181

  20. Determination of the maximum product yield from glucoamylase-producing Aspergillus niger grown in the recycling fermentor.

    PubMed

    van Verseveld, H W; Metwally, M; el Sayed, M; Osman, M; Schrickx, J M; Stouthamer, A H

    1991-01-01

    Aspergillus niger has been grown in glucose- and maltose-limited recycling cultures to determine the maximum growth yield, the maximum product yield for glucoamylase production, and the maintenance requirements at very slow specific growth rates. Using the linear equation for substrate utilization, and using the experimental data from both recycling experiments, both the maximum growth yield, Yxsm, and the maximum product yield, Ypsm, could be determined. The values estimated were 157 g biomass per mol maltose for Yxsm and 100 g protein per mol maltose for Ypsm. Expressed on a C1-basis these values are 0.52 and 0.36 C-mole per C-mol for respectively Yxsm and Ypsm. The found value for Ypsm is half the value found for alkaline serine protease production in Bacillus licheniformis, and it can be concluded that formation of extracellular protein is more energy consuming in filamentous fungi than in prokaryotic organisms. Maintenance requirements are no significant factor during growth of Aspergillus niger, and reported maintenance requirements are most probably due to differentiation. PMID:1807200

  1. Effect of media composition and growth conditions on production of beta-glucosidase by Aspergillus niger C-6.

    PubMed

    Garca-Kirchner, O; Segura-Granados, M; Rodrguez-Pascual, P

    2005-01-01

    The hydrolytic activity of fungal originated beta-glucosidase is exploited in several biotechnological processes to increase the rate and extent of saccharification of several cellulosic materials by hydrolyzing the cellobiose which inhibits cellulases. In a previous presentation, we reported the screening and liquid fermentation with Aspergillus niger, strain C-6 for beta-glucosidase production at shake flask cultures in a basal culture medium with mineral salts, corn syrup liquor, and different waste lignocellulosic materials as the sole carbon source obtaining the maximum enzymatic activity after 5-6 d of 8.5 IU/mL using native sugar cane bagasse. In this work we describe the evaluation of fermentation conditions: growth temperature, medium composition, and pH, also the agitation and aeration effects for beta-glucosidase production under submerged culture using a culture media with corn syrup liquor (CSL) and native sugar cane bagasse pith as the sole carbon source in a laboratory fermenter. The maximum enzyme titer of 7.2 IU/mL was obtained within 3 d of fermentation. This indicates that beta-glucosidase productivity by Aspergillus niger C-6 is function of culture conditions, principally temperature, pH, culture medium conditions, and the oxygen supply given in the bioreactor. Results obtained suggest that this strain is a potential microorganism that can reach a major level of enzyme production and also for enzyme characterization. PMID:15917612

  2. Effect of citrate on Aspergillus niger phytase adsorption and catalytic activity in soil

    NASA Astrophysics Data System (ADS)

    Mezeli, Malika; Menezes-Blackburn, Daniel; Zhang, Hao; Giles, Courtney; George, Timothy; Shand, Charlie; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Stutter, Marc; Blackwell, Martin; Darch, Tegan; Wearing, Catherine; Haygarth, Philip

    2015-04-01

    Current developments in cropping systems that promote mobilisation of phytate in agricultural soils, by exploiting plant-root exudation of phytase and organic acids, offer potential for developments in sustainable phosphorus use. However, phytase adsorption to soil particles and phytate complexion has been shown to inhibit phytate dephosphorylation, thereby inhibiting plant P uptake, increasing the risk of this pool contributing to diffuse pollution and reducing the potential benefits of biotechnologies and management strategies aimed to utilise this abundant reserve of 'legacy' phosphorus. Citrate has been seen to increase phytase catalytic efficiency towards complexed forms of phytate, but the mechanisms by which citrate promotes phytase remains poorly understood. In this study, we evaluated phytase (from Aspergillus niger) inactivation, and change in catalytic properties upon addition to soil and the effect citrate had on adsorption of phytase and hydrolysis towards free, precipitated and adsorbed phytate. A Langmuir model was fitted to phytase adsorption isotherms showing a maximum adsorption of 0.23 nKat g-1 (19 mg protein g-1) and affinity constant of 435 nKat gˉ1 (8.5 mg protein g-1 ), demonstrating that phytase from A.niger showed a relatively low affinity for our test soil (Tayport). Phytases were partially inhibited upon adsorption and the specific activity was of 40.44 nKat mgˉ1 protein for the free enzyme and 25.35 nKat mgˉ1 protein when immobilised. The kinetics of adsorption detailed that most of the adsorption occurred within the first 20 min upon addition to soil. Citrate had no effect on the rate or total amount of phytase adsorption or loss of activity, within the studied citrate concentrations (0-4mM). Free phytases in soil solution and phytase immobilised on soil particles showed optimum activity (>80%) at pH 4.5-5.5. Immobilised phytase showed greater loss of activity at pH levels over 5.5 and lower activities at the secondary peak at pH 2.5 when compared to the free enzymes or in soil solution. The effect of ionic strength on enzyme activity was studied by increasing NaCl concentration on the activity buffer. A significant loss of activity was seen at ionic strengths over 0.6 M but enzymes in soil solution showed increased loss of activity on initial increase in ionic strength. No significant effect of citrate on phytase catalytic efficiency was observed towards free, adsorbed and precipitated (Al, Fe, Ca) phytate, except for the free phytase towards adsorbed phytase which showed a ~160% increase in P release with the addition of citric acid. This data suggest that citrate addition has no impact on the adsorption or catalytic activity of phytase in soil solution or that immobilised on soil particles, suggesting that its impact is associated with the availability of the substrate rather than effects on the enzyme per se. The ionic strength of soil solution does, however, have an impact on phytase activity suggesting that both wetting/drying cycles and fertilisation will have discrete impacts on the activity of phytases once released to soil and thus their ability to make organic P available for uptake by plants and microbes.

  3. Enhanced hexadecane degradation and low biomass production by Aspergillus niger exposed to an electric current in a model system.

    PubMed

    Velasco-Alvarez, Nancy; González, Ignacio; Damian-Matsumura, Pablo; Gutiérrez-Rojas, Mariano

    2011-01-01

    The effects of an electric current on growth and hexadecane (HXD) degradation by Aspergillus niger growth were determined. A 450-mL electrochemical cell with titanium ruthenium-oxide coated electrodes and packed with 15 g of perlite (inert biomass support) was inoculated with A. niger (2.0×10(7) spores (g of dry inert support)(-1)) and incubated for 12 days (30 °C; constant ventilation). 4.5 days after starting culture a current of 0.42 mA cm(-2) was applied for 24h. The current reduced (52±11%) growth of the culture as compared to that of a culture not exposed to current. However, HXD degradation was 96±1.4% after 8 days whereas it was 81±1.2% after 12 days in control cultures. Carbon balances of cultures not exposed to current suggested an assimilative metabolism, but a non-assimilative metabolism when the current was applied. This change can be related to an increase in total ATP content. The study contributes to the knowledge on the effects of current on the mycelial growth phase of A. niger, and suggests the possibility of manipulating the metabolism of this organism with electric current. PMID:20739180

  4. Enzymatic synthesis of fructooligosaccharides by inulinases from Aspergillus niger and Kluyveromyces marxianus NRRL Y-7571 in aqueous-organic medium.

    PubMed

    Silva, Marceli Fernandes; Rigo, Diane; Mossi, Vincius; Golunski, Simone; Kuhn, Graciele de Oliveira; Di Luccio, Marco; Dallago, Rogrio; de Oliveira, Dbora; Oliveira, J Vladimir; Treichel, Helen

    2013-05-01

    This work is focused on the synthesis of the fructooligosaccharides (FOS) from sucrose and inulin, using free, immobilized and pre-treated immobilized inulinase from Kluyveromyces marxianus NRRL Y 7571 and Aspergillus niger in an aqueous-organic system. Initially, the influence of pre-treatment using four different gases, propane, n-butane, CO(2) and liquefied petroleum gas (LPG), was investigated towards FOS production and best results were found when both enzymes were previously treated with LPG. The best reaction yields were obtained when the immobilized enzymes were treated with LPG. Considering FOS synthesis using the enzyme from A. niger, yields of 26.62% of GF2 (kestose), 30.62% of GF3 (nystose) and 8.47% of GF4 (fructosyl nystose) were achieved using sucrose as substrate. Using inulinases from K. marxianus NRRL Y 7571, 11.89% of GF2 and 20.83% of GF3 were obtained, using inulin as substrate. However, promising results were achieved using the free form of inulinase from A. niger (77.19% of GF2; 14.03% of GF3 and 0.07% of GF4) using inulin as substrate. PMID:23265469

  5. Quantification of the fractal nature of mycelial aggregation in Aspergillus niger submerged cultures

    PubMed Central

    Papagianni, Maria

    2006-01-01

    Background Fractal geometry estimates have proven useful in studying the growth strategies of fungi in response to different environments on soil or on agar substrates, but their use in mycelia grown submerged is still rare. In the present study, the effects of certain important fermentation parameters, such as the spore inoculum level, phosphate and manganese concentrations in the medium, on mycelial morphology of the citric acid producer Aspergillus niger were determined by fractal geometry. The value of employing fractal geometry to describe mycelial structures was examined in comparison with information from other descriptors including classic morphological parameters derived from image analysis. Results Fractal analysis of distinct morphological forms produced by fermentation conditions that influence fungal morphology and acid production, showed that the two fractal dimensions DBS (box surface dimension) and DBM (box mass dimension) are very sensitive indexes, capable of describing morphological differences. The two box-counting methods applied (one applied to the whole mass of the mycelial particles and the other applied to their surface only) enabled evaluation of fractal dimensions for mycelial particles in this analysis in the region of DBS = 1.20–1.70 and DBM = 1.20–2.70. The global structure of sufficiently branched mycelia was described by a single fractal dimension D, which did not exceed 1.30. Such simple structures are true mass fractals (DBS = DBM = D) and they could be young mycelia or dispersed forms of growth produced by very dense spore inocula (108–109 spores/ml) or by addition of manganese in the medium. Mycelial clumps and pellets were effectively discriminated by fractal analysis. Fractal dimension values were plotted together with classic morphological parameters derived from image analysis for comparisons. Their sensitivity to treatment was analogous to the sensitivity of classic morphological parameters suggesting that they could be equally used as morphological descriptors. Conclusion Starting from a spore, the mycelium develops as a mass fractal and, depending on culture conditions, it either turns to a surface fractal or remains a mass fractal. Since fractal dimensions give a measure of the degree of complexity and the mass filling properties of an object, it may be possible that a large number of morphological parameters which contribute to the overall complexity of the particles, could be replaced by these indexes effectively. PMID:16472407

  6. Comprehensive annotation of secondary metabolite biosynthetic genes and gene clusters of Aspergillus nidulans, A. fumigatus, A. niger and A. oryzae

    PubMed Central

    2013-01-01

    Background Secondary metabolite production, a hallmark of filamentous fungi, is an expanding area of research for the Aspergilli. These compounds are potent chemicals, ranging from deadly toxins to therapeutic antibiotics to potential anti-cancer drugs. The genome sequences for multiple Aspergilli have been determined, and provide a wealth of predictive information about secondary metabolite production. Sequence analysis and gene overexpression strategies have enabled the discovery of novel secondary metabolites and the genes involved in their biosynthesis. The Aspergillus Genome Database (AspGD) provides a central repository for gene annotation and protein information for Aspergillus species. These annotations include Gene Ontology (GO) terms, phenotype data, gene names and descriptions and they are crucial for interpreting both small- and large-scale data and for aiding in the design of new experiments that further Aspergillus research. Results We have manually curated Biological Process GO annotations for all genes in AspGD with recorded functions in secondary metabolite production, adding new GO terms that specifically describe each secondary metabolite. We then leveraged these new annotations to predict roles in secondary metabolism for genes lacking experimental characterization. As a starting point for manually annotating Aspergillus secondary metabolite gene clusters, we used antiSMASH (antibiotics and Secondary Metabolite Analysis SHell) and SMURF (Secondary Metabolite Unknown Regions Finder) algorithms to identify potential clusters in A. nidulans, A. fumigatus, A. niger and A. oryzae, which we subsequently refined through manual curation. Conclusions This set of 266 manually curated secondary metabolite gene clusters will facilitate the investigation of novel Aspergillus secondary metabolites. PMID:23617571

  7. SHIFTING THE PH PROFILE OF ASPERGILLUS NIGER PHYA PHYTASE TO MATCH THE STOMACH PH ENHANCES ITS EFFECTIVENESS AS AN ANIMAL FEED ADDITIVE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental pollution of phosphorus (P) from animal waste is a major problem in agriculture because simple-stomached animals such as swine, poultry, and fish cannot digest phosphorus (as phytate) present in plant feeds. To alleviate this problem, a phytase from Aspergillus niger PhyA is widely us...

  8. Altering the Substrate Specificity Site of Aspergillus Niger PhyB shifts the pH optimum to pH 3.2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytases are of biotechnological importance as animal feed additives for their ability to catalyze the hydrolysis of phosphate from phytate for absorption by simple-stomached animals, and to reduce their fecal phosphorus excretion. Aspergillus niger PhyB has high catalytic activity at low pHs around...

  9. Impact of Assay conditions on activity estimate and kinetics comparison of Aspergillus niger PhyA and Escherichia coli AppA2 phytases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was to compare three phytase activity assays and kinetics of Aspergillus niger PhyA and Escherichia coli AppA2 phytases expressed in Pichia pastoris at the observed stomach pH of 3.5. In Experiment 1, equivalent phytase activities in the crude preparations of PhyA and AppA2 were tested ...

  10. Correlation of Mycotoxin Fumonisin B2 Production and Presence of the Fumonisin Biosynthetic Gene fum8 in Aspergillus niger from Grape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumonisins are mycotoxins associated with cancer and several other serious diseases in humans and animals. Production of the mycotoxins has been reported for over two decades in Fusarium species, but has been reported only recently in strains of Aspergillus niger. In addition, a homologue of the f...

  11. Characterization of toxigenic and atoxigenic Aspergillus flavus isolates from pistachio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty eight Aspergillus flavus isolates collected from a pistachio orchard in California were analyzed for production of aflatoxin (AF), cyclopiazonic acid (CPA), vegetative compatibility groups (VCGs) and mating types. All toxigenic isolates produced both AFB1 and CPA. Twenty-one percent of the i...

  12. Diversity of black Aspergilli isolated from raisins in Argentina: Polyphasic approach to species identification and development of SCAR markers for Aspergillus ibericus.

    PubMed

    Giaj Merlera, G; Muñoz, S; Coelho, I; Cavaglieri, L R; Torres, A M; Reynoso, M M

    2015-10-01

    Aspergillus section Nigri is a heterogeneous fungal group including some ochratoxin A producer species that usually contaminate raisins. The section contains the Series Carbonaria which includes the toxigenic species Aspergillus carbonarius and nontoxigenic Aspergillus ibericus that are phenotypically undistinguishable. The aim of this study was to examine the diversity of black aspergilli isolated from raisins and to develop a specific genetic marker to distinguish A. ibericus from A. carbonarius. The species most frequently found in raisins in this study were Aspergillus tubingensis (35.4%) and A. carbonarius (32.3%), followed by Aspergillus luchuensis (10.7%), Aspergillus japonicus (7.7%), Aspergillus niger (6.2%), Aspergillus welwitschiae (4.6%) and A. ibericus (3.1%). Based on inter-simple sequence repeat (ISSR) fingerprinting profiles of major Aspergillus section Nigri members, a sequence-characterized amplified region (SCAR) marker was identified. Primers were designed based on the conserved regions of the SCAR marker and were utilized in a PCR for simultaneous identification of A. carbonarius and A. ibericus. The detection level of the SCAR-PCR was found to be 0.01 ng of purified DNA. The present SCAR-PCR is rapid and less cumbersome than conventional identification techniques and could be a supplementary strategy and a reliable tool for high-throughput sample analysis. PMID:26114593

  13. Differential Expression of Three α-Galactosidase Genes and a Single β-Galactosidase Gene from Aspergillus niger

    PubMed Central

    de Vries, Ronald P.; van den Broeck, Hetty C.; Dekkers, Ester; Manzanares, Paloma; de Graaff, Leo H.; Visser, Jaap

    1999-01-01

    A gene encoding a third α-galactosidase (AglB) from Aspergillus niger has been cloned and sequenced. The gene consists of an open reading frame of 1,750 bp containing six introns. The gene encodes a protein of 443 amino acids which contains a eukaryotic signal sequence of 16 amino acids and seven putative N-glycosylation sites. The mature protein has a calculated molecular mass of 48,835 Da and a predicted pI of 4.6. An alignment of the AglB amino acid sequence with those of other α-galactosidases revealed that it belongs to a subfamily of α-galactosidases that also includes A. niger AglA. A. niger AglC belongs to a different subfamily that consists mainly of prokaryotic α-galactosidases. The expression of aglA, aglB, aglC, and lacA, the latter of which encodes an A. niger β-galactosidase, has been studied by using a number of monomeric, oligomeric, and polymeric compounds as growth substrates. Expression of aglA is only detected on galactose and galactose-containing oligomers and polymers. The aglB gene is expressed on all of the carbon sources tested, including glucose. Elevated expression was observed on xylan, which could be assigned to regulation via XlnR, the xylanolytic transcriptional activator. Expression of aglC was only observed on glucose, fructose, and combinations of glucose with xylose and galactose. High expression of lacA was detected on arabinose, xylose, xylan, and pectin. Similar to aglB, the expression on xylose and xylan can be assigned to regulation via XlnR. All four genes have distinct expression patterns which seem to mirror the natural substrates of the encoded proteins. PMID:10347026

  14. Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone.

    SciTech Connect

    Chiang, Yi Ming; Meyer, Kristen M; Praseuth, Michael; Baker, Scott E; Bruno, Kenneth S; Wang, Clay C

    2010-12-06

    The genome sequencing of the fungus Aspergillus niger, an industrial workhorse, uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of YWA1, a precursor of fungal DHN melanin. Our results show that the A. niger alb1 PKS is responsible for the production of the polyketide precursor for DHN melanin biosynthesis. Deletion of alb1 elimnates the production of major metabolites, naphtho-γ-pyrones. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.

  15. Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone.

    PubMed

    Chiang, Yi-Ming; Meyer, Kristen M; Praseuth, Michael; Baker, Scott E; Bruno, Kenneth S; Wang, Clay C C

    2011-04-01

    The genome sequencing of the fungus Aspergillus niger uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a non-reducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene we name albA is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of the naphtho-γ-pyrone precursor for the 1,8-dihydroxynaphthalene (DHN) melanin/spore pigment. Our results show that the A. nigeralbA PKS is responsible for both the production of the spore pigment precursor and a family of naphtho-γ-pyrones commonly found in significant quantity in A. niger culture extracts. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism. PMID:21176790

  16. Characterization of a polyketide synthase in Aspergillus niger whose product is a precursor for both dihydroxynaphthalene (DHN) melanin and naphtho-γ-pyrone

    PubMed Central

    Chiang, Yi-Ming; Meyer, Kristen M.; Praseuth, Michael; Baker, Scott E.; Bruno, Kenneth S.; Wang, Clay C. C.

    2011-01-01

    The genome sequencing of the fungus Aspergillus niger uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene we name albA is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of the naphtho-γ-pyrone precursor for the 1,8-dihydroxynaphthalene (DHN) melanin/spore pigment. Our results show that the A. nigeralbA PKS is responsible for both the production of the spore pigment precursor and a family of naphtho-γ-pyrones commonly found in significant quantity in A. niger culture extracts. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism. PMID:21176790

  17. Phosphate solubilization and promotion of maize growth by Penicillium oxalicum P4 and Aspergillus niger P85 in a calcareous soil.

    PubMed

    Yin, Zhongwei; Shi, Fachao; Jiang, Hongmei; Roberts, Daniel P; Chen, Sanfeng; Fan, Bingquan

    2015-12-01

    Alternative tactics for improving phosphorus nutrition in crop production are needed in China and elsewhere, as the overapplication of phosphatic fertilizers can adversely impact agricultural sustainability. Penicillium oxalicum P4 and Aspergillus niger P85 were isolated from a calcareous soil in China that had been exposed to excessive application of phosphatic fertilizer for decades. Each isolate excreted a number of organic acids into, acidified, and solubilized phosphorus in a synthetic broth containing insoluble tricalcium phosphate or rock phosphate. Isolate P4, applied as a seed treatment, increased maize fresh mass per plant when rock phosphate was added to the calcareous soil in greenhouse pot studies. Isolate P85 did not increase maize fresh mass per plant but did significantly increase total phosphorus per plant when rock phosphate was added. Significant increases in 7 and 4 organic acids were detected in soil in association with isolates P4 and P85, respectively, relative to the soil-only control. The quantity and (or) number of organic acids produced by these isolates increased when rock phosphate was added to the soil. Both isolates also significantly increased available phosphorus in soil in the presence of added rock phosphate and effectively colonized the maize rhizosphere. Studies reported here indicate that isolate P4 is adapted to and capable of promoting maize growth in a calcareous soil. Plant-growth promotion by this isolate is likely due, at least in part, to increased phosphorus availability resulting from the excretion of organic acids into, and the resulting acidification of, this soil. PMID:26469739

  18. The intra- and extracellular proteome of Aspergillus niger growing on defined medium with xylose or maltose as carbon substrate

    PubMed Central

    2010-01-01

    Background The filamentous fungus Aspergillus niger is well-known as a producer of primary metabolites and extracellular proteins. For example, glucoamylase is the most efficiently secreted protein of Aspergillus niger, thus the homologous glucoamylase (glaA) promoter as well as the glaA signal sequence are widely used for heterologous protein production. Xylose is known to strongly repress glaA expression while maltose is a potent inducer of glaA promoter controlled genes. For a more profound understanding of A. niger physiology, a comprehensive analysis of the intra- and extracellular proteome of Aspergillus niger AB1.13 growing on defined medium with xylose or maltose as carbon substrate was carried out using 2-D gel electrophoresis/Maldi-ToF and nano-HPLC MS/MS. Results The intracellular proteome of A. niger growing either on xylose or maltose in well-aerated controlled bioreactor cultures revealed striking similarities. In both cultures the most abundant intracellular protein was the TCA cycle enzyme malate-dehydrogenase. Moreover, the glycolytic enzymes fructose-bis-phosphate aldolase and glyceraldehyde-3-phosphate-dehydrogenase and the flavohemoglobin FhbA were identified as major proteins in both cultures. On the other hand, enzymes involved in the removal of reactive oxygen species, such as superoxide dismutase and peroxiredoxin, were present at elevated levels in the culture growing on maltose but only in minor amounts in the xylose culture. The composition of the extracellular proteome differed considerably depending on the carbon substrate. In the secretome of the xylose-grown culture, a variety of plant cell wall degrading enzymes were identified, mostly under the control of the xylanolytic transcriptional activator XlnR, with xylanase B and ferulic acid esterase as the most abundant ones. The secretome of the maltose-grown culture did not contain xylanolytic enzymes, instead high levels of catalases were found and glucoamylase (multiple spots) was identified as the most abundant extracellular protein. Surprisingly, the intracellular proteome of A. niger growing on xylose in bioreactor cultures differed more from a culture growing in shake flasks using the same medium than from the bioreactor culture growing on maltose. For example, in shake flask cultures with xylose as carbon source the most abundant intracellular proteins were not the glycolytic and the TCA cycle enzymes and the flavohemoglobin, but CipC, a protein of yet unknown function, superoxide dismutase and an NADPH dependent aldehyde reductase. Moreover, vacuolar proteases accumulated to higher and ER-resident chaperones and foldases to lower levels in shake flask compared to the bioreactor cultures. Conclusions The utilization of xylose or maltose was strongly affecting the composition of the secretome but of minor influence on the composition of the intracellular proteome. On the other hand, differences in culture conditions (pH control versus no pH control, aeration versus no aeration and stirring versus shaking) have a profound effect on the intracellular proteome. For example, lower levels of ER-resident chaperones and foldases and higher levels of vacuolar proteases render shake flask conditions less favorable for protein production compared to controlled bioreactor cultures. PMID:20406453

  19. Comparative study of toxicity of azo dye Procion Red MX-5B following biosorption and biodegradation treatments with the fungi Aspergillus niger and Aspergillus terreus.

    PubMed

    Almeida, E J R; Corso, C R

    2014-10-01

    Azo dyes are an important class of environmental contaminants and are characterized by the presence of one or more azo bonds (-N=N-) in their molecular structure. Effluents containing these compounds resist many types of treatments due to their molecular complexity. Therefore, alternative treatments, such as biosorption and biodegradation, have been widely studied to solve the problems caused by these substances, such as their harmful effects on the environment and organisms. The aim of the present study was to evaluate biosorption and biodegradation of the azo dye Procion Red MX-5B in solutions with the filamentous fungi Aspergillus niger and Aspergillus terreus. Decolorization tests were performed, followed by acute toxicity tests using Lactuca sativa seeds and Artemia salina larvae. Thirty percent dye removal of the solutions was achieved after 3 h of biosorption. UV-Vis spectroscopy revealed that removal of the dye molecules occurred without major molecular changes. The acute toxicity tests confirmed lack of molecular degradation following biosorption with A. niger, as toxicity to L. sativa seed reduced from 5% to 0%. For A. salina larvae, the solutions were nontoxic before and after treatment. In the biodegradation study with the fungus A. terreus, UV-Vis and FTIR spectroscopy revealed molecular degradation and the formation of secondary metabolites, such as primary and secondary amines. The biodegradation of the dye molecules was evaluated after 24, 240 and 336 h of treatment. The fungal biomass demonstrated considerable affinity for Procion Red MX-5B, achieving approximately 100% decolorization of the solutions by the end of treatment. However, the solutions resulting from this treatment exhibited a significant increase in toxicity, inhibiting the growth of L. sativa seeds by 43% and leading to a 100% mortality rate among the A. salina larvae. Based on the present findings, biodegradation was effective in the decolorization of the samples, but generated toxic metabolites, while biosorption was effective in both decolorization and reducing the toxicity of the solutions. PMID:25048922

  20. Identification and susceptibility of Aspergillus section nigri in china: prevalence of species and paradoxical growth in response to echinocandins.

    PubMed

    Li, Yali; Wan, Zhe; Liu, Wei; Li, Ruoyu

    2015-02-01

    Molecular identification and in vitro antifungal susceptibility tests of 43 Aspergillus section Nigri isolates from China were performed. Aspergillus niger and Aspergillus tubingensis were present in almost equal numbers. All of the isolates had low MIC/MECs (minimum effective concentrations) for the 7 common antifungals, and a paradoxical effect was observed for the first time in response to caspofungin and micafungin. PMID:25502526

  1. [Effect of alcoholic extracts of wild plants on the inhibition of growth of Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium moniliforme and Fusarium poae moulds].

    PubMed

    Tequida-Meneses, Martn; Cortez-Rocha, Mario; Rosas-Burgos, Ema Carina; Lpez-Sandoval, Susana; Corrales-Maldonado, Consuelo

    2002-06-01

    Fungicidal activity of wild plants Larrea tridentata, Karwinskia humboldtiana, Ricinus communis, Eucalyptus globulus, Ambrosia ambrosioides, Nicotiana glauca, Ambrosia confertiflora, Datura discolor, Baccharis glutinosa, Proboscidea parviflora, Solanum rostratum, Jatropha cinerea, Salpianthus macrodonthus y Sarcostemma cynanchoides was evaluated against the moulds species Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium poae y Fusarium moniliforme moulds species. Alcoholic extracts 6% (w/v) were prepared using six grams of dried plant powders (leaves and stems) and alcohol (70% ethanol or 70% methanol). A spore suspension (1x10(6); ufc/ml) of each mould was prepared by adding saline solution (0.85%) and 0.1% tween 80. The extracts were mixed with Czapeck yeast agar (CYA) at 45-50 degrees C in 1:10 relation on Petri dishes. Triplicate Petri dishes of each treatment and for each mould were centrally inoculated and three Petri dishes were used without treatment as controls. The inoculated dishes and controls were incubated at 25 +/- 2 degrees C for eight days. The incubated dishes were examined each 48 h and after the colony diameter (radial growth) was measured. Two mould species were controlled by L. tridentata, B. glutinosa and P. parviflora. Extracts of L. tridentata in methanol or ethanol at 41.5-100% inhibited all six species of moulds. PMID:12828509

  2. Production of plant cell wall degrading enzymes by monoculture and co-culture of Aspergillus niger and Aspergillus terreus under SSF of banana peels

    PubMed Central

    Rehman, Shazia; Aslam, Hina; Ahmad, Aqeel; Khan, Shakeel Ahmed; Sohail, Muhammad

    2014-01-01

    Filamentous fungi are considered to be the most important group of microorganisms for the production of plant cell wall degrading enzymes (CWDE), in solid state fermentations. In this study, two fungal strains Aspergillus niger MS23 and Aspergillus terreus MS105 were screened for plant CWDE such as amylase, pectinase, xylanase and cellulases (?-glucosidase, endoglucanase and filterpaperase) using a novel substrate, Banana Peels (BP) for SSF process. This is the first study, to the best of our knowledge, to use BP as SSF substrate for plant CWDE production by co-culture of fungal strains. The titers of pectinase were significantly improved in co-culture compared to mono-culture. Furthermore, the enzyme preparations obtained from monoculture and co-culture were used to study the hydrolysis of BP along with some crude and purified substrates. It was observed that the enzymatic hydrolysis of different crude and purified substrates accomplished after 26 h of incubation, where pectin was maximally hydrolyzed by the enzyme preparations of mono and co-culture. Along with purified substrates, crude materials were also proved to be efficiently degraded by the cocktail of the CWDE. These results demonstrated that banana peels may be a potential substrate in solid-state fermentation for the production of plant cell wall degrading enzymes to be used for improving various biotechnological and industrial processes. PMID:25763058

  3. Synthesis of a hybrid polymer-inorganic biomimetic support incorporating in situ pectinase from Aspergillus niger ATCC 9642.

    PubMed

    Bustamante-Vargas, Cindy Elena; Mignoni, Marcelo Luis; de Oliveira, Débora; Venquiaruto, Luciana Dornelles; Valduga, Eunice; Toniazzo, Geciane; Dallago, Rogério Marcos

    2015-08-01

    The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through the biomimetic mineralization method for immobilization in situ of a pectinolytic extract from Aspergillus niger ATCC 9642 via entrapment technique. The efficiency of immobilization reached 72.7%. Sodium oxalate buffer (100 mM, pH 5.5) was selected as adjuvant of the immobilization process by allowing the formation of a calcified shell around the calcium alginate capsule, significantly increasing the stability to storage, thermal and recycling of the enzymatic immobilized pectinolytic extract. The pH and temperature for maximum activity were from 5.0 to 6.0 and 60 to 80 °C, respectively. The new hybrid support can be a potential alternative to obtain immobilized pectinases with properties for advantageous industrial applications. PMID:25894295

  4. Secondary substrate binding strongly affects activity and binding affinity of Bacillus subtilis and Aspergillus niger GH11 xylanases.

    PubMed

    Cuyvers, Sven; Dornez, Emmie; Rezaei, Mohammad N; Pollet, Annick; Delcour, Jan A; Courtin, Christophe M

    2011-04-01

    The secondary substrate binding site (SBS) of Bacillus subtilis and Aspergillus niger glycoside hydrolase family 11 xylanases was studied by site-directed mutagenesis and evaluation of activity and binding properties of mutant enzymes on different substrates. Modification of the SBS resulted in an up to three-fold decrease in the relative activity of the enzymes on polymeric versus oligomeric substrates and highlighted the importance of several amino acids in the SBS forming hydrogen bonds or hydrophobic stacking interactions with substrates. Weakening of the SBS increased K(d) values by up to 70-fold in binding affinity tests using natural substrates. The impact that modifications in the SBS have both on activity and on binding affinity towards polymeric substrates clearly shows that such structural elements can increase the efficiency of these single domain enzymes on their natural substrates. PMID:21261814

  5. Treatment of African catfish, Clarias gariepinus wastewater utilizing phytoremediation of microalgae, Chlorella sp. with Aspergillus niger bio-harvesting.

    PubMed

    Nasir, Nurfarahana Mohd; Bakar, Nur Syuhada Abu; Lananan, Fathurrahman; Abdul Hamid, Siti Hajar; Lam, Su Shiung; Jusoh, Ahmad

    2015-08-01

    This study focuses on the evaluation of the performance of Chlorella sp. in removing nutrient in aquaculture wastewater and its correlation with the kinetic growth of Chlorella sp. The treatment was applied with various Chlorella sp. inoculation dosage ranging from 0% to 60% (v/v) of wastewater. The optimum inoculation dosage was recorded at 30% (v/v) with effluent concentration of ammonia and orthophosphate recording at 0.012mgL(-1) and 0.647mgL(-1), respectively on Day 11. The optimum dosage for bio-flocculation process was obtained at 30mgL(-1) of Aspergillus niger with a harvesting efficiency of 97%. This type of development of phytoremediation with continuous bio-harvesting could promote the use of sustainable green technology for effective wastewater treatment. PMID:25791330

  6. High titer gluconic acid fermentation by Aspergillus niger from dry dilute acid pretreated corn stover without detoxification.

    PubMed

    Zhang, Hongsen; Zhang, Jian; Bao, Jie

    2016-03-01

    This study reported a high titer gluconic acid fermentation using dry dilute acid pretreated corn stover (DDAP) hydrolysate without detoxification. The selected fermenting strain Aspergillus niger SIIM M276 was capable of inhibitor degradation thus no detoxification on pretreated corn stover was required. Parameters of gluconic acid fermentation in corn stover hydrolysate were optimized in flasks and in fermentors to achieve 76.67g/L gluconic acid with overall yield of 94.91%. The sodium gluconate obtained from corn stover was used as additive for extending setting time of cement mortar and similar function was obtained with starch based sodium gluconate. This study provided the first high titer gluconic acid production from lignocellulosic feedstock with potential of industrial applications. PMID:26724553

  7. A qualitative and quantitative high-throughput assay for screening of gluconate high-yield strains by Aspergillus niger.

    PubMed

    Shi, Fei; Tan, Jun; Chu, Ju; Wang, Yonghong; Zhuang, Yingping; Zhang, Siliang

    2015-02-01

    A novel two-step high-throughput strategy was developed for screening of gluconate high-yield strains by Aspergillus niger. The first step was fast qualitative assay according to the indicator color change, the second step was quantitative assay according to the absorbance of chelate formed with Cu(2+) at 810nm. The accuracy of high-throughput assay was comparable to that of high-performance liquid chromatography (HPLC). The correlation coefficient between CuSO4 assay and HPLC assays was exceeding 0.99 by statistical analysis. As a result, 3 high-yield mutants were screened out from 1000 viable single colonies, the mutants II-2-A1, IV-7-C6, and V-11-C5 were further validated in 5L of bioreactor. The average production rates were 15.5%, 32.8%, and 12.1% higher than that of the parental strain, respectively. PMID:25498457

  8. Application of Plackett-Burman Experimental Design for Lipase Production by Aspergillus niger Using Shea Butter Cake.

    PubMed

    Salihu, Aliyu; Bala, Muntari; Bala, Shuaibu M

    2013-01-01

    Plackett-Burman design was used to efficiently select important medium components affecting the lipase production by Aspergillus niger using shea butter cake as the main substrate. Out of the eleven medium components screened, six comprising of sucrose, (NH4)2SO4, Na2HPO4, MgSO4, Tween-80, and olive oil were found to contribute positively to the overall lipase production with a maximum production of 3.35?U/g. Influence of tween-80 on lipase production was investigated, and 1.0% (v/w) of tween-80 resulted in maximum lipase production of 6.10?U/g. Thus, the statistical approach employed in this study allows for rapid identification of important medium parameters affecting the lipase production, and further statistical optimization of medium and process parameters can be explored using response surface methodology. PMID:25937979

  9. Application of Plackett-Burman Experimental Design for Lipase Production by Aspergillus niger Using Shea Butter Cake

    PubMed Central

    Salihu, Aliyu; Bala, Muntari; Bala, Shuaibu M.

    2013-01-01

    Plackett-Burman design was used to efficiently select important medium components affecting the lipase production by Aspergillus niger using shea butter cake as the main substrate. Out of the eleven medium components screened, six comprising of sucrose, (NH4)2SO4, Na2HPO4, MgSO4, Tween-80, and olive oil were found to contribute positively to the overall lipase production with a maximum production of 3.35?U/g. Influence of tween-80 on lipase production was investigated, and 1.0% (v/w) of tween-80 resulted in maximum lipase production of 6.10?U/g. Thus, the statistical approach employed in this study allows for rapid identification of important medium parameters affecting the lipase production, and further statistical optimization of medium and process parameters can be explored using response surface methodology. PMID:25937979

  10. Purification and characterization of two distinct acidic phytases with broad pH stability from Aspergillus niger NCIM 563

    PubMed Central

    Soni, S. K.; Magdum, A.

    2010-01-01

    Aspergillus niger NCIM 563 produced two different extracellular phytases (Phy I and Phy II) under submerged fermentation conditions at 30C in medium containing dextrin-glucose-sodium nitrate-salts. Both the enzymes were purified to homogeneity using Rotavapor concentration, Phenyl-Sepharose column chromatography and Sephacryl S-200 gel filtration. The molecular mass of Phy I and II as determined by SDSPAGE and gel filtration were 66, 264, 150 and 148kDa respectively, indicating that Phy I consists of four identical subunits and Phy II is a monomer. The pI values of Phy I and II were 3.55 and 3.91, respectively. Phy I was highly acidic with optimum pH of 2.5 and was stable over a broad pH range (1.59.0) while Phy II showed a pH optimum of 5.0 with stability in the range of pH 3.59.0. Phy I exhibited very broad substrate specificity while Phy II was more specific for sodium phytate. Similarly Phy II was strongly inhibited by Ag+, Hg2+ (1mM) metal ions and Phy I was partially inhibited. Peptide analysis by Mass Spectrometry (MS) MALDI-TOF also indicated that both the proteins were totally different. The Km for Phy I and II for sodium phytate was 2.01 and 0.145mM while Vmax was 5,018 and 1,671?molmin?1mg?1, respectively. The N-terminal amino acid sequences of Phy I and Phy II were FSYGAAIPQQ and GVDERFPYTG, respectively. Phy II showed no homology with Phy I and any other known phytases from the literature suggesting its unique nature. This, according to us, is the first report of two distinct novel phytases from Aspergillus niger. PMID:20976287

  11. Growth Kinetics and Mechanistic Action of Reactive Oxygen Species Released by Silver Nanoparticles from Aspergillus niger on Escherichia coli

    PubMed Central

    Ninganagouda, Shivaraj; Rathod, Vandana; Singh, Dattu; Hiremath, Jyoti; Singh, Ashish Kumar; Mathew, Jasmine; ul-Haq, Manzoor

    2014-01-01

    Silver Nanoparticles (AgNPs), the real silver bullet, are known to have good antibacterial properties against pathogenic microorganisms. In the present study AgNPs were prepared from extracellular filtrate of Aspergillus niger. Characterization of AgNPs by UV-Vis spectrum reveals specific surface plasmon resonance at peak 416?nm; TEM photographs revealed the size of the AgNPs to be 2055?nm. Average diameter of the produced AgNPs was found to be 73?nm with a zeta potential that was ?24?mV using Malvern Zetasizer. SEM micrographs showed AgNPs to be spherical with smooth morphology. EDS revealed the presence of pure metallic AgNPs along with carbon and oxygen signatures. Of the different concentrations (0, 2.5, 5, 10, and 15??g/mL) used 10??g/mL were sufficient to inhibit 107?CFU/mL of E. coli. ROS production was measured using DCFH-DA method and the the free radical generation effect of AgNPs on bacterial growth inhibition was investigated by ESR spectroscopy. This paper not only deals with the damage inflicted on microorganisms by AgNPs but also induces cell death through the production of ROS released by AgNPs and also growth kinetics of E. coli supplemented with AgNPs produced by A. niger. PMID:25028666

  12. Identification of an l-Arabinose Reductase Gene in Aspergillus niger and Its Role in l-Arabinose Catabolism*

    PubMed Central

    Mojzita, Dominik; Penttil, Merja; Richard, Peter

    2010-01-01

    The first enzyme in the pathway for l-arabinose catabolism in eukaryotic microorganisms is a reductase, reducing l-arabinose to l-arabitol. The enzymes catalyzing this reduction are in general nonspecific and would also reduce d-xylose to xylitol, the first step in eukaryotic d-xylose catabolism. It is not clear whether microorganisms use different enzymes depending on the carbon source. Here we show that Aspergillus niger makes use of two different enzymes. We identified, cloned, and characterized an l-arabinose reductase, larA, that is different from the d-xylose reductase, xyrA. The larA is up-regulated on l-arabinose, while the xyrA is up-regulated on d-xylose. There is however an initial up-regulation of larA also on d-xylose but that fades away after about 4 h. The deletion of the larA gene in A. niger results in a slow growth phenotype on l-arabinose, whereas the growth on d-xylose is unaffected. The l-arabinose reductase can convert l-arabinose and d-xylose to their corresponding sugar alcohols but has a higher affinity for l-arabinose. The Km for l-arabinose is 54 6 mm and for d-xylose 155 15 mm. PMID:20511228

  13. Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of variants of monoamine oxidase from Aspergillus niger

    SciTech Connect

    Atkin, Kate E.; Reiss, Renate; Turner, Nicholas J.; Brzozowski, Andrzej M.; Grogan, Gideon

    2008-03-01

    Crystals of A. niger monoamine oxidase variants display P2{sub 1} or P4{sub 1}2{sub 1}2/P4{sub 3}2{sub 1}2 symmetry, with eight or two molecules in the asymmetric unit, respectively. Monoamine oxidase from Aspergillus niger (MAO-N) is an FAD-dependent enzyme that catalyses the conversion of terminal amines to their corresponding aldehydes. Variants of MAO-N produced by directed evolution have been shown to possess altered substrate specificity. Crystals of two of these variants (MAO-N-3 and MAO-N-5) have been obtained; the former displays P2{sub 1} symmetry with eight molecules per asymmetric unit and the latter has P4{sub 1}2{sub 1}2 or P4{sub 3}2{sub 1}2 symmetry and two molecules per asymmetric unit. Solution of these structures will help shed light on the molecular determinants of improved activity and high enantioselectivity towards a broad range of substrates.

  14. Development of a highly efficient indigo dyeing method using indican with an immobilized beta-glucosidase from Aspergillus niger.

    PubMed

    Song, Jingyuan; Imanaka, Hiroyuki; Imamura, Koreyoshi; Kajitani, Kouichi; Nakanishi, Kazuhiro

    2010-09-01

    A highly efficient method for dyeing textiles with indigo is described. In this method, the substrate, indican is first hydrolyzed at an acidic pH of 3 using an immobilized beta-glucosidase to produce indoxyl, under which conditions indigo formation is substantially repressed. The textile sample is then dipped in the prepared indoxyl solution and the textile is finally exposed to ammonia vapor for a short time, resulting in rapid indigo dyeing. As an enzyme, we selected a beta-glucosidase from Aspergillus niger, which shows a high hydrolytic activity towards indican and was thermally stable at temperatures up to 50-60 degrees C, in an acidic pH region. The A. niger beta-glucosidase, when immobilized on Chitopearl BCW-3001 by treatment with glutaraldehyde, showed an optimum reaction pH similar to that of the free enzyme with a slightly higher thermal stability. The kinetics for the hydrolysis of indican at pH 3, using the purified free and immobilized enzymes was found to follow Michaelis-Menten type kinetics with weak competitive inhibition by glucose. Using the immobilized enzyme, we successfully carried out repeated-batch and continuous hydrolyses of indican at pH 3 when nitrogen gas was continuously supplied to the substrate solution. Various types of model textiles were dyed using the proposed method although the color yield varied, depending on the type of textile used. PMID:20547334

  15. Conversion of orange peel to L-galactonic acid in a consolidated process using engineered strains of Aspergillus niger

    PubMed Central

    2014-01-01

    Citrus processing waste is a leftover from the citrus processing industry and is available in large amounts. Typically, this waste is dried to produce animal feed, but sometimes it is just dumped. Its main component is the peel, which consists mostly of pectin, with D-galacturonic acid as the main monomer. Aspergillus niger is a filamentous fungus that efficiently produces pectinases for the hydrolysis of pectin and uses the resulting D-galacturonic acid and most of the other components of citrus peel for growth. We used engineered A. niger strains that were not able to catabolise D-galacturonic acid, but instead converted it to L-galactonic acid. These strains also produced pectinases for the hydrolysis of pectin and were used for the conversion of pectin in orange peel to L-galactonic acid in a consolidated process. The D-galacturonic acid in the orange peel was converted to L-galactonic acid with a yield close to 90%. Submerged and solid-state fermentation processes were compared. PMID:24949267

  16. Lipase Production in Solid-State Fermentation Monitoring Biomass Growth of Aspergillus niger Using Digital Image Processing

    NASA Astrophysics Data System (ADS)

    Dutra, Julio C. V.; da Terzi, Selma C.; Bevilaqua, Juliana Vaz; Damaso, Mônica C. T.; Couri, Sônia; Langone, Marta A. P.; Senna, Lilian F.

    The aim of this study was to monitor the biomass growth of Aspergillus niger in solid-state fermentation (SSF) for lipase production using digital image processing technique. The strain A. niger 11T53A14 was cultivated in SSF using wheat bran as support, which was enriched with 0.91% (m/v) of ammonium sulfate. The addition of several vegetable oils (castor, soybean, olive, corn, and palm oils) was investigated to enhance lipase production. The maximum lipase activity was obtained using 2% (m/m) castor oil. In these conditions, the growth was evaluated each 24 h for 5 days by the glycosamine content analysis and digital image processing. Lipase activity was also determined. The results indicated that the digital image process technique can be used to monitor biomass growth in a SSF process and to correlate biomass growth and enzyme activity. In addition, the immobilized esterification lipase activity was determined for the butyl oleate synthesis, with and without 50% v/v hexane, resulting in 650 and 120 U/g, respectively. The enzyme was also used for transesterification of soybean oil and ethanol with maximum yield of 2.4%, after 30 min of reaction.

  17. Removal of arsenic from aqueous environments by native and chemically modified biomass of Aspergillus niger and Neosartorya fischeri.

    PubMed

    Littera, Pavol; Urk, Martin; Sevc, Jaroslav; Kolenck, Marek; Gardosov, Katarna; Molnrov, Marianna

    2011-01-01

    Arsenic removal from aqueous solutions by biomass of two fungal strains, Aspergillus niger and Neosartorya fischeri, was assessed. The biosorption capacity of fungal biomass was studied within the As(V) concentration range of approximately 0.2 to 5.0 mg L(-1) at two different pH values (pH 5 and 7). With increasing initial arsenic concentration, the biosorption capacity of both fungal strains increased almost linearly and achieved the sorption capacity of 0.317 and 0.124 mg g(-1) for biomass of N. fischeri and A. niger, respectively. The effect of biomass treatment with FeCl3 and HCI on As(III) and As(V) uptake was also studied. The optimum biosorption pH as well as the effect ofbiomass treatment was found to be dependent on the fungal strain used. Treatment with FeCl3 and HCl did not result in any significant increase in arsenic uptake. To the contrary, treatment with ferric oxyhydroxide was found to be very effective and virtually 100% of the arsenic was removed from the samples of contaminated natural water. PMID:21970163

  18. Role of Aspergillus niger acrA in Arsenic Resistance and Its Use as the Basis for an Arsenic Biosensor

    PubMed Central

    Choe, Se-In; Gravelat, Fabrice N.; Al Abdallah, Qusai; Lee, Mark J.; Gibbs, Bernard F.

    2012-01-01

    Arsenic contamination of groundwater sources is a major issue worldwide, since exposure to high levels of arsenic has been linked to a variety of health problems. Effective methods of detection are thus greatly needed as preventive measures. In an effort to develop a fungal biosensor for arsenic, we first identified seven putative arsenic metabolism and transport genes in Aspergillus niger, a widely used industrial organism that is generally regarded as safe (GRAS). Among the genes tested for RNA expression in response to arsenate, acrA, encoding a putative plasma membrane arsenite efflux pump, displayed an over 200-fold increase in gene expression in response to arsenate. We characterized the function of this A. niger protein in arsenic efflux by gene knockout and confirmed that AcrA was located at the cell membrane using an enhanced green fluorescent protein (eGFP) fusion construct. Based on our observations, we developed a putative biosensor strain containing a construct of the native promoter of acrA fused with egfp. We analyzed the fluorescence of this biosensor strain in the presence of arsenic using confocal microscopy and spectrofluorimetry. The biosensor strain reliably detected both arsenite and arsenate in the range of 1.8 to 180 ?g/liter, which encompasses the threshold concentrations for drinking water set by the World Health Organization (10 and 50 ?g/liter). PMID:22467499

  19. Role of Aspergillus niger acrA in arsenic resistance and its use as the basis for an arsenic biosensor.

    PubMed

    Choe, Se-In; Gravelat, Fabrice N; Al Abdallah, Qusai; Lee, Mark J; Gibbs, Bernard F; Sheppard, Donald C

    2012-06-01

    Arsenic contamination of groundwater sources is a major issue worldwide, since exposure to high levels of arsenic has been linked to a variety of health problems. Effective methods of detection are thus greatly needed as preventive measures. In an effort to develop a fungal biosensor for arsenic, we first identified seven putative arsenic metabolism and transport genes in Aspergillus niger, a widely used industrial organism that is generally regarded as safe (GRAS). Among the genes tested for RNA expression in response to arsenate, acrA, encoding a putative plasma membrane arsenite efflux pump, displayed an over 200-fold increase in gene expression in response to arsenate. We characterized the function of this A. niger protein in arsenic efflux by gene knockout and confirmed that AcrA was located at the cell membrane using an enhanced green fluorescent protein (eGFP) fusion construct. Based on our observations, we developed a putative biosensor strain containing a construct of the native promoter of acrA fused with egfp. We analyzed the fluorescence of this biosensor strain in the presence of arsenic using confocal microscopy and spectrofluorimetry. The biosensor strain reliably detected both arsenite and arsenate in the range of 1.8 to 180 ?g/liter, which encompasses the threshold concentrations for drinking water set by the World Health Organization (10 and 50 ?g/liter). PMID:22467499

  20. Mechanism of Cr(VI) reduction by Aspergillus niger: enzymatic characteristic, oxidative stress response, and reduction product.

    PubMed

    Gu, Yanling; Xu, Weihua; Liu, Yunguo; Zeng, Guangming; Huang, Jinhui; Tan, Xiaofei; Jian, Hao; Hu, Xi; Li, Fei; Wang, Dafei

    2015-04-01

    Bioremediation of hexavalent chromium by Aspergillus niger was attributed to the reduction product (trivalent chromium) that could be removed in precipitation and immobilized inside the fungal cells and on the surface of mycelium. The site location of reduction was conducted with assays of the permeabilized cells, cell-free extracts, and cell debris, which confirmed that the chromate reductase was mainly located in the soluble fraction of cells. The oxidation-reduction process was accompanied by the increase of reactive oxygen species and antioxidant levels after hexavalent chromium treatment. Michaelis-Menten constant (K(m)) and maximum reaction rate (V(max)), obtained from the Lineweaver-Burk plot were 14.68 μM and 434 μM min(-1) mg(-1) of protein, respectively. Scanning electron microscopy and Raman spectra analyses manifested that both Cr(VI) and Cr(III) species were present on the mycelium. Fourier transform-infrared spectroscopy analysis suggested that carboxyl, hydroxide, amine, amide, cyano-group, and phosphate groups from the fungal cell wall were involved in chromium binding by the complexation with the Cr(III) and Cr(VI) species. A Cr(VI) removal mechanism of Cr(VI) reduction followed by the surface immobilization and intracellular accumulation of Cr(III) in living A. niger was present. PMID:25408081

  1. Transcriptomic Insights into the Physiology of Aspergillus niger Approaching a Specific Growth Rate of Zero ▿ †

    PubMed Central

    Jørgensen, Thomas R.; Nitsche, Benjamin M.; Lamers, Gerda E.; Arentshorst, Mark; van den Hondel, Cees A.; Ram, Arthur F.

    2010-01-01

    The physiology of filamentous fungi at growth rates approaching zero has been subject to limited study and exploitation. With the aim of uncoupling product formation from growth, we have revisited and improved the retentostat cultivation method for Aspergillus niger. A new retention device was designed allowing reliable and nearly complete cell retention even at high flow rates. Transcriptomic analysis was used to explore the potential for product formation at very low specific growth rates. The carbon- and energy-limited retentostat cultures were highly reproducible. While the specific growth rate approached zero (<0.005 h−1), the growth yield stabilized at a minimum (0.20 g of dry weight per g of maltose). The severe limitation led to asexual differentiation, and the supplied substrate was used for spore formation and secondary metabolism. Three physiologically distinct phases of the retentostat cultures were subjected to genome-wide transcriptomic analysis. The severe substrate limitation and sporulation were clearly reflected in the transcriptome. The transition from vegetative to reproductive growth was characterized by downregulation of genes encoding secreted substrate hydrolases and cell cycle genes and upregulation of many genes encoding secreted small cysteine-rich proteins and secondary metabolism genes. Transcription of known secretory pathway genes suggests that A. niger becomes adapted to secretion of small cysteine-rich proteins. The perspective is that A. niger cultures as they approach a zero growth rate can be used as a cell factory for production of secondary metabolites and cysteine-rich proteins. We propose that the improved retentostat method can be used in fundamental studies of differentiation and is applicable to filamentous fungi in general. PMID:20562270

  2. Growth performance of broiler chickens fed diets containing shea nut (Vitellaria paradoxa, Gaertn.) meal fermented with Aspergillus niger.

    PubMed

    Dei, H K; Rose, S P; Mackenzie, A M; Amarowicz, R

    2008-09-01

    Shea nut meal is a by-product of the shea fat industry in West Africa. The objective was to determine the effect of shea nut meal fermentation using Aspergillus niger on growth performance of broiler chickens. An expeller shea nut meal was fermented in a closed plastic container for 8 d after the addition of 0.25 g of A. niger spores per kg of shea nut meal in 2 parts of water. Each of the 2 shea nut meal samples (the unfermented and fermented meals) replaced wheatfeed in a control diet at 100 g/kg and fed to 128 Ross 308 male broiler chickens (22 to 36 d). There were 8 replicates per diet (2 shea nut meal samples and the control wheatfeed diet) and 4 birds per replicate in cages (0.6 m x 0.6 m x 0.9 m). Analysis of variance of data was used to compare the treatment means. The fermentation method reduced the concentrations of total soluble phenolics (21.9%), bound plus soluble proanthocyanidins (34.5%), soluble proanthocyanidins (24.7%), and hydrolysable tannins (52.9%) in the shea nut meal. Broilers fed the fermented meal exhibited higher (P < 0.001) growth performance than those fed the unfermented meal. However, the growth performance of broilers fed each of the shea nut meal-based diets was lower (P < 0.001) than that of broilers fed the control diet. Mean live weight gain of broilers fed the fermented shea nut meal diet was 82% of that of broilers fed the control diet. The fermentation of shea nut meal using A. niger has the potential to improve the nutritive value of shea nut meal for poultry, but requires further development. PMID:18753445

  3. Overexpression of a modified 6-phosphofructo-1-kinase results in an increased itaconic acid productivity in Aspergillus niger

    PubMed Central

    2013-01-01

    A modified 6-phosphofructo-1-kinase was expressed in a citrate producing Aspergillus niger strain in combination with cis-aconitate decarboxylase from Aspergillus terreus to study the effect on the production of itaconic acid. The modified pfkA gene was also expressed in combination with the itaconic acid biosynthetic cluster from A. terreus, which consists of cis-aconitate decarboxylase cadA, a putative mitochondrial transporter mttA and a putative plasmamembrane transporter mfsA. The combined expression of pfkA and cadA resulted in increased citrate levels, but did not show increased itaconic acid levels. The combined expression of pfkA with the itaconic acid biosynthetic cluster resulted in significantly increased itaconic acid production at earlier time points. Also the itaconic acid productivity increased significantly. The maximum itaconic acid productivity that was reached under these conditions was 0.15 g/L/h, which is only a factor 17 lower than the 2.5 g/L/h that according to the US Department of Energy should be achieved to have an economically feasible production process. PMID:24034235

  4. Overexpression of a modified 6-phosphofructo-1-kinase results in an increased itaconic acid productivity in Aspergillus niger.

    PubMed

    van der Straat, Laura; Tamayo-Ramos, Juan A; Schonewille, Tom; de Graaff, Leo H

    2013-01-01

    A modified 6-phosphofructo-1-kinase was expressed in a citrate producing Aspergillus niger strain in combination with cis-aconitate decarboxylase from Aspergillus terreus to study the effect on the production of itaconic acid. The modified pfkA gene was also expressed in combination with the itaconic acid biosynthetic cluster from A. terreus, which consists of cis-aconitate decarboxylase cadA, a putative mitochondrial transporter mttA and a putative plasmamembrane transporter mfsA. The combined expression of pfkA and cadA resulted in increased citrate levels, but did not show increased itaconic acid levels. The combined expression of pfkA with the itaconic acid biosynthetic cluster resulted in significantly increased itaconic acid production at earlier time points. Also the itaconic acid productivity increased significantly. The maximum itaconic acid productivity that was reached under these conditions was 0.15 g/L/h, which is only a factor 17 lower than the 2.5 g/L/h that according to the US Department of Energy should be achieved to have an economically feasible production process. PMID:24034235

  5. RNA-sequencing reveals the complexities of the transcriptional response to lignocellulosic biofuel substrates in Aspergillus niger

    PubMed Central

    Delmas, Stéphane; Ibbett, Roger; Kokolski, Matthew; Neiteler, Almar; van Munster, Jolanda M; Wilson, Raymond; Blythe, Martin J; Gaddipati, Sanyasi; Tucker, Gregory A; Archer, David B

    2015-01-01

    Background Saprobic fungi are the predominant industrial sources of Carbohydrate Active enZymes (CAZymes) used for the saccharification of lignocellulose during the production of second generation biofuels. The production of more effective enzyme cocktails is a key objective for efficient biofuel production. To achieve this objective, it is crucial to understand the response of fungi to lignocellulose substrates. Our previous study used RNA-seq to identify the genes induced in Aspergillus niger in response to wheat straw, a biofuel feedstock, and showed that the range of genes induced was greater than previously seen with simple inducers. Results In this work we used RNA-seq to identify the genes induced in A. niger in response to short rotation coppice willow and compared this with the response to wheat straw from our previous study, at the same time-point. The response to willow showed a large increase in expression of genes encoding CAZymes. Genes encoding the major activities required to saccharify lignocellulose were induced on willow such as endoglucanases, cellobiohydrolases and xylanases. The transcriptome response to willow had many similarities with the response to straw with some significant differences in the expression levels of individual genes which are discussed in relation to differences in substrate composition or other factors. Differences in transcript levels include higher levels on wheat straw from genes encoding enzymes classified as members of GH62 (an arabinofuranosidase) and CE1 (a feruloyl esterase) CAZy families whereas two genes encoding endoglucanases classified as members of the GH5 family had higher transcript levels when exposed to willow. There were changes in the cocktail of enzymes secreted by A. niger when cultured with willow or straw. Assays for particular enzymes as well as saccharification assays were used to compare the enzyme activities of the cocktails. Wheat straw induced an enzyme cocktail that saccharified wheat straw to a greater extent than willow. Genes not encoding CAZymes were also induced on willow such as hydrophobins as well as genes of unknown function. Several genes were identified as promising targets for future study. Conclusions By comparing this first study of the global transcriptional response of a fungus to willow with the response to straw, we have shown that the inducing lignocellulosic substrate has a marked effect upon the range of transcripts and enzymes expressed by A. niger. The use by industry of complex substrates such as wheat straw or willow could benefit efficient biofuel production. PMID:26457194

  6. Verruculogen production in airborne and clinical isolates of Aspergillus fumigatus Fres.

    PubMed

    Kosalec, Ivan; Klari?, Maja Segvi?; Pepeljnjak, Stjepan

    2005-12-01

    Among airborne aspergilli sampled in outdoor air of the Zagreb area (2002/2003), Aspergillus niger (v. Teigh.) and A. fumigatus (Fres.) were the most abundant species (20-30%), with low mean annual concentrations (0.21-1.04 CFU m-3). Higher concentrations of A. fumigatus were observed in autumn and winter (0.5-1.05 CFU m-3) than in spring and summer (0-0.4 CFU m-3). On the other hand, A. fumigatus was found to be the most frequent isolate from upper and/or lower respiratory tracts of imunocompromised patients in many studies. This species produces several mycotoxins, including the tremorgenic mycotoxin verruculogen that can be found in spores and during myceliar growth. Verruculogen production ability was tested on 30 airborne and 33 clinical isolates of A. fumigatus. In both groups, high percentage of verruculogen-producing strains was noticed (84% of airborne and 91% of clinical isolates). Verruculogen production was not significantly different in the groups of airborne isolates (0.34+/-0.16 mg mL-1), and clinical isolates (0.26+/-0.19 mg mL-1). PMID:16375825

  7. Identification of a Classical Mutant in the Industrial Host Aspergillus niger by Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites

    PubMed Central

    Niu, Jing; Arentshorst, Mark; Nair, P. Deepa S.; Dai, Ziyu; Baker, Scott E.; Frisvad, Jens C.; Nielsen, Kristian F.; Punt, Peter J.; Ram, Arthur F.J.

    2015-01-01

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. niger has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a ΔlaeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. Finally, we show that our systems genetics approach is a powerful tool to identify trait mutations. PMID:26566947

  8. Identification of a Classical Mutant in the Industrial Host Aspergillus niger by Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites.

    PubMed

    Niu, Jing; Arentshorst, Mark; Nair, P Deepa S; Dai, Ziyu; Baker, Scott E; Frisvad, Jens C; Nielsen, Kristian F; Punt, Peter J; Ram, Arthur F J

    2015-01-01

    The asexual filamentous fungus Aspergillus niger is an important industrial cell factory for citric acid production. In this study, we genetically characterized a UV-generated A. niger mutant that was originally isolated as a nonacidifying mutant, which is a desirable trait for industrial enzyme production. Physiological analysis showed that this mutant did not secrete large amounts of citric acid and oxalic acid, thus explaining the nonacidifying phenotype. As traditional complementation approaches to characterize the mutant genotype were unsuccessful, we used bulk segregant analysis in combination with high-throughput genome sequencing to identify the mutation responsible for the nonacidifying phenotype. Since A. niger has no sexual cycle, parasexual genetics was used to generate haploid segregants derived from diploids by loss of whole chromosomes. We found that the nonacidifying phenotype was caused by a point mutation in the laeA gene. LaeA encodes a putative methyltransferase-domain protein, which we show here to be required for citric acid production in an A. niger lab strain (N402) and in other citric acid production strains. The unexpected link between LaeA and citric acid production could provide new insights into the transcriptional control mechanisms related to citric acid production in A. niger. Interestingly, the secondary metabolite profile of a ?laeA strain differed from the wild-type strain, showing both decreased and increased metabolite levels, indicating that LaeA is also involved in regulating the production of secondary metabolites. Finally, we show that our systems genetics approach is a powerful tool to identify trait mutations. PMID:26566947

  9. Mechanisms for solubilization of various insoluble phosphates and activation of immobilized phosphates in different soils by an efficient and salinity-tolerant Aspergillus niger strain An2.

    PubMed

    Li, Xiaolong; Luo, Lijin; Yang, Jinshui; Li, Baozhen; Yuan, Hongli

    2015-03-01

    Mechanisms for solubilization of different types of phosphates and activation of immobilized phosphates in different types of soils by an efficient fungal strain An2 were explored and evaluated in this study. An2 was isolated from a Chinese cabbage rhizosphere soil and identified as Aspergillus niger. It could fast release up to 1722, 2066, and 2356 mg L(-1) of soluble phosphorus (P) from 1 % Ca3(PO4)2, Mg3(PO4)2, and AlPO4 (Ca-P, Mg-P, and Al-P) and 215 and 179 mg L(-1) from 0.5 % FePO4 and rock phosphate (Fe-P and RP), respectively. HPLC assay demonstrated that An2 mainly secreted oxalic acid to solubilize Ca-P, Mg-P, Al-P, and Fe-P whereas secreted tartaric acid to solubilize RP. Furthermore, An2 could tolerate salinity up to 4 % NaCl without impairing its phosphate-solubilizing ability. The simulation experiments validated that An2 was able to effectively activate immobilized phosphates in general calcareous, acidic, as well as saline-alkali soils with high total P content. This study shows new insights into the mechanisms for microbial solubilization of different types of phosphates and supports the future application of strain An2 in different types of soils to effectively activate P for plants. PMID:25561059

  10. The impact of dose, irradiance and growth conditions on Aspergillus niger (renamed A. brasiliensis) spores low-pressure (LP) UV inactivation.

    PubMed

    Taylor-Edmonds, Lizbeth; Lichi, Tovit; Rotstein-Mayer, Adi; Mamane, Hadas

    2015-01-01

    The use of Aspergillus niger (A. niger) fungal spores as challenge organism for UV reactor validation studies is attractive due to their high UV-resistance and non-pathogenic nature. However A. niger spores UV dose-response was dependent upon sporulation conditions and did not follow the Bunsen-Roscoe Principle of time-dose reciprocity. Exposure to 8h of natural sunlight for 10 consecutive days increased UV resistance when compared to spores grown solely in dark conditions. Application of 250 mJ cm(-2) at high irradiance (0.11 mW cm(-2)) resulted in a 2-log inactivation; however, at low irradiance (0.022 mW cm(-2)) a 1-log inactivation was achieved. In addition, surface electron microscopy (SEM) images revealed morphological changes between the control and UV exposed spores in contrast to other well accepted UV calibrated test organisms, which show no morphological difference with UV exposure. PMID:25723059

  11. Evaluation of glucosidases of Aspergillus niger strain comparing with other glucosidases in transformation of ginsenoside Rb1 to ginsenosides Rg3

    PubMed Central

    Chang, Kyung Hoon; Jo, Mi Na; Kim, Kee-Tae; Paik, Hyun-Dong

    2013-01-01

    The transformation of ginsenoside Rb1 into a specific minor ginsenoside using Aspergillus niger KCCM 11239, as well as the identification of the transformed products and the pathway via thin layer chromatography and high performance liquid chromatography were evaluated to develop a new biologically active material. The conversion of ginsenoside Rb1 generated Rd, Rg3, Rh2, and compound K although the reaction rates were low due to the low concentration. In enzymatic conversion, all of the ginsenoside Rb1 was converted to ginsenoside Rd and ginsenoside Rg3 after 24h of incubation. The crude enzyme (?-glucosidase) from A.niger KCCM 11239 hydrolyzed the ?-(1?6)-glucosidic linkage at the C-20 of ginsenoside Rb1 to generate ginsenoside Rd and ginsenoside Rg3. Our experimental demonstration showing that A.niger KCCM 11239 produces the ginsenoside-hydrolyzing ?-glucosidase reflects the feasibility of developing a specific bioconversion process to obtain active minor ginsenosides. PMID:24558310

  12. Proteome analysis of Aspergillus niger: Lactate added in starch-containing medium can increase production of the mycotoxin fumonisin B2 by modifying acetyl-CoA metabolism

    PubMed Central

    2009-01-01

    Background Aspergillus niger is a filamentous fungus found in the environment, on foods and feeds and is used as host for production of organic acids, enzymes and proteins. The mycotoxin fumonisin B2 was recently found to be produced by A. niger and hence very little is known about production and regulation of this metabolite. Proteome analysis was used with the purpose to reveal how fumonisin B2 production by A. niger is influenced by starch and lactate in the medium. Results Fumonisin B2 production by A. niger was significantly increased when lactate and starch were combined in the medium. Production of a few other A. niger secondary metabolites was affected similarly by lactate and starch (fumonisin B4, orlandin, desmethylkotanin and pyranonigrin A), while production of others was not (ochratoxin A, ochratoxin alpha, malformin A, malformin C, kotanin, aurasperone B and tensidol B). The proteome of A. niger was clearly different during growth on media containing 3% starch, 3% starch + 3% lactate or 3% lactate. The identity of 59 spots was obtained, mainly those showing higher or lower expression levels on medium with starch and lactate. Many of them were enzymes in primary metabolism and other processes that affect the intracellular level of acetyl-CoA or NADPH. This included enzymes in the pentose phosphate pathway, pyruvate metabolism, the tricarboxylic acid cycle, ammonium assimilation, fatty acid biosynthesis and oxidative stress protection. Conclusions Lactate added in a medium containing nitrate and starch can increase fumonisin B2 production by A. niger as well as production of some other secondary metabolites. Changes in the balance of intracellular metabolites towards a higher level of carbon passing through acetyl-CoA and a high capacity to regenerate NADPH during growth on medium with starch and lactate were found to be the likely cause of this effect. The results lead to the hypothesis that fumonisin production by A. niger is regulated by acetyl-CoA. PMID:20003296

  13. Incidence of fumonisin B2 production within Aspergillus section Nigri populations isolated from California raisins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fungi belonging to Aspergillus section Nigri occur frequently and in high populations on grapes. Species within this section include A. niger, A. tubingensis, and A. carbonarius, and are potential sources for mycotoxins including ochratoxin A and fumonisin B2 (FB2) in grapes and grape products. As...

  14. Sexual origins of British Aspergillus nidulans isolates.

    PubMed Central

    Geiser, D M; Arnold, M L; Timberlake, W E

    1994-01-01

    Aspergillus nidulans is a holomorphic fungus, capable of producing both meiotically and mitotically derived spores. Meiosis may be an evolutionary relic in this species because it is potentially capable of mitotic recombination and because most Aspergilli lack the ability to produce meiotic spores. We tested the null hypothesis that meiosis has been a major factor in the origin of strains of A. nidulans from Great Britain by estimating linkage disequilibrium among restriction fragment length polymorphisms. These strains belong to different heterokaryon compatibility groups and are thus incapable of undergoing mitotic recombination with one another, so any recombination evidenced by linkage equilibrium is assumed to be the result of meiosis. Eleven cosmid clones of known chromosomal origin were used to generate multilocus genotypes based on restriction-pattern differences for each heterokaryon compatibility group. Low levels of genetic variation and little linkage disequilibrium were found, indicating that the heterokaryon compatibility groups represent recently diverged lineages that arose via meiotic recombination. The null hypothesis that loci are independent could not be rejected. Additionally, low levels of electrophoretic karyotype variation were indicative of meiosis. We conclude that although A. nidulans probably propagates in a primarily clonal fashion, recombination events are frequent enough to disrupt the stable maintenance of clonal genotypes. We further conclude that the British heterokaryon compatibility groups arose via recombination and not through novel mutation. Images PMID:7907796

  15. Proteomic Analysis of the Secretory Response of Aspergillus niger to D-Maltose and D-Xylose

    PubMed Central

    Ferreira de Oliveira, José Miguel P.; van Passel, Mark W. J.; Schaap, Peter J.; de Graaff, Leo H.

    2011-01-01

    Fungi utilize polysaccharide substrates through extracellular digestion catalyzed by secreted enzymes. Thus far, protein secretion by the filamentous fungus Aspergillus niger has mainly been studied at the level of individual proteins and by genome and transcriptome analyses. To extend these studies, a complementary proteomics approach was applied with the aim to investigate the changes in secretome and microsomal protein composition resulting from a shift to a high level secretion condition. During growth of A. niger on d-sorbitol, small amounts of d-maltose or d-xylose were used as inducers of the extracellular amylolytic and xylanolytic enzymes. Upon induction, protein compositions in the extracellular broth as well as in enriched secretory organelle (microsomal) fractions were analyzed using a shotgun proteomics approach. In total 102 secreted proteins and 1,126 microsomal proteins were identified in this study. Induction by d-maltose or d-xylose resulted in the increase in specific extracellular enzymes, such as glucoamylase A on d-maltose and β-xylosidase D on d-xylose, as well as of microsomal proteins. This reflects the differential expression of selected genes coding for dedicated extracellular enzymes. As expected, the addition of extra d-sorbitol had no effect on the expression of carbohydrate-active enzymes, compared to addition of d-xylose or d-maltose. Furthermore, d-maltose induction caused an increase in microsomal proteins related to translation (e.g., Rpl15) and vesicular transport (e.g., the endosomal-cargo receptor Erv14). Millimolar amounts of the inducers d-maltose and d-xylose are sufficient to cause a direct response in specific protein expression levels. Also, after induction by d-maltose or d-xylose, the induced enzymes were found in microsomes and extracellular. In agreement with our previous findings for d-xylose induction, d-maltose induction leads to recruitment of proteins involved in proteasome-mediated degradation. PMID:21698107

  16. Corn steep liquor as a nutrition adjunct for the production of Aspergillus niger lipase and hydrolysis of oils thereof.

    PubMed

    Edwinoliver, N G; Thirunavukarasu, K; Purushothaman, S; Rose, C; Gowthaman, M K; Kamini, N R

    2009-11-25

    Corn steep liquor (CSL) has been used as a nutrition adjunct for the production of an extracellular lipase from Aspergillus niger, which has immense importance as an additive in laundry detergent formulations. A five-level four-factorial central composite design was chosen to determine the optimal medium components with four critical variables, namely, CSL, NH4H2PO4, Na2HPO4, and sesame oil, that were found to be influential for lipase production by the classical one-factor-at-a-time method. The model suggested that all of the factors chosen had a significant impact on lipase production, and the optimum values of the influential parameters were CSL, 2.0%, w/v; NH4H2PO4, 0.05%, w/v; Na2HPO4, 0.75%, w/v; and sesame oil, 2.0%, w/v, with an activity of 26.7 U/mL at 48 h and 30 degrees C, which was 2.16-fold higher than the initial activity (12 U/mL) obtained by the conventional one-factor-at-a-time method. Furthermore, the enzyme has good potential for the hydrolysis of vegetable oils and fish oils, and a hydrolytic ratio of 88.73% was obtained with palm oil at 48 h. The utilization of CSL and sesame oil for lipase production from A. niger makes the process green, because both are renewable substrates and economically viable at an industrial scale. PMID:19860451

  17. Expression of the Aspergillus niger glucose oxidase gene in Saccharomyces cerevisiae and its potential applications in wine production.

    PubMed

    Malherbe, D F; du Toit, M; Cordero Otero, R R; van Rensburg, P; Pretorius, I S

    2003-06-01

    There is a growing consumer demand for wines containing lower levels of alcohol and chemical preservatives. The objectives of this study were to express the Aspergillus niger gene encoding a glucose oxidase (GOX; beta- d-glucose:oxygen oxidoreductase, EC 1.1.3.4) in Saccharomyces cerevisiae and to evaluate the transformants for lower alcohol production and inhibition of wine spoilage organisms, such as acetic acid bacteria and lactic acid bacteria, during fermentation. The A. niger structural glucose oxidase (gox) gene was cloned into an integration vector (YIp5) containing the yeast mating pheromone alpha-factor secretion signal (MFalpha1(S)) and the phosphoglycerate-kinase-1 gene promoter (PGK1(P)) and terminator (PGK1(T)). The PGK1(P)- MFalpha1(S)- gox- PGK1(T) cassette (designated GOX1) was introduced into a laboratory strain (Sigma1278) of S. cerevisiae. Yeast transformants were analysed for the production of biologically active glucose oxidase on selective agar plates and in liquid assays. The results indicated that the recombinant glucose oxidase was active and was produced beginning early in the exponential growth phase, leading to a stable level in the stationary phase. The yeast transformants also displayed antimicrobial activity in a plate assay against lactic acid bacteria and acetic acid bacteria. This might be explained by the fact that a final product of the GOX enzymatic reaction is hydrogen peroxide, a known antimicrobial agent. Microvinification with the laboratory yeast transformants resulted in wines containing 1.8-2.0% less alcohol. This was probably due to the production of d-glucono-delta-lactone and gluconic acid from glucose by GOX. These results pave the way for the development of wine yeast starter culture strains for the production of wine with reduced levels of chemical preservatives and alcohol. PMID:12764565

  18. The AngFus3 Mitogen-Activated Protein Kinase Controls Hyphal Differentiation and Secondary Metabolism in Aspergillus niger

    PubMed Central

    Priegnitz, Bert-Ewald; Brandt, Ulrike; Pahirulzaman, Khomaizon A. K.; Dickschat, Jeroen S.

    2015-01-01

    Adaptation to a changing environment is essential for the survival and propagation of sessile organisms, such as plants or fungi. Filamentous fungi commonly respond to a worsening of their growth conditions by differentiation of asexually or sexually produced spores. The formation of these specialized cell types is, however, also triggered as part of the general life cycle by hyphal age or density. Spores typically serve for dispersal and, therefore, translocation but can also act as resting states to endure times of scarcity. Eukaryotic differentiation in response to environmental and self-derived signals is commonly mediated by three-tiered mitogen-activated protein (MAP) kinase signaling cascades. Here, we report that the MAP kinase Fus3 of the black mold Aspergillus niger (AngFus3) and its upstream kinase AngSte7 control vegetative spore formation and secondary metabolism. Mutants lacking these kinases are defective in conidium induction in response to hyphal density but are fully competent in starvation-induced sporulation, indicating that conidiation in A. niger is triggered by various independent signals. In addition, the mutants exhibit an altered profile of volatile metabolites and secrete dark pigments into the growth medium, suggesting a dysregulation of the secondary metabolism. By assigning the AngFus3 MAP kinase pathway to the transduction of a potentially self-derived trigger, this work contributes to the unraveling of the intricate signaling networks controlling fungal differentiation. Moreover, our data further support earlier observations that differentiation and secondary metabolism are tightly linked in filamentous fungi. PMID:25888553

  19. Characterization of Aspergillus niger endo-1,4-?-glucanase ENG1 secreted from Saccharomyces cerevisiae using different expression vectors.

    PubMed

    Taipakova, S M; Smekenov, I T; Saparbaev, M K; Bissenbaev, A K

    2015-01-01

    Heterologous expression of Aspergillus niger endo-1,4-?-glucanase (ENG1) in Saccharomyces cerevisiae was tested both with an episomal plasmid vector (YEGAp/eng1) and a yeast vector capable of integration into the HO locus of the S. cerevisiae chromosome (pHO-GAPDH-eng1-KanMX4-HO). In both cases, eng1 gene expression in yeast, with its native signal sequence for secretion, was under the control of the strong glyceraldehyde 3-phosphate dehydrogenase (GAPDH) promoter. We aimed to verify how each expression system affects protein expression, posttranslational modification, and biochemical properties. Expression of eng1 from the episomal plasmid vector YEGAp/eng1 significantly slowed the growth of a yeast cell culture. However, expression of eng1 from the vector integrated into the HO locus of the chromosome did not cause growth suppression, and the enzyme activity in a culture supernatant was maintained throughout the incubation time. ENG1 has optimum catalytic activity at pH 6.0, and is stable in the pH range 5.0-9.0. The enzyme's optimum temperature for catalytic activity at pH 6.0 is 70C; importantly, more than 95% of the enzyme's initial activity remained after a 2-h incubation at 60C. The biochemical characterization of ENG1 confirmed the correct expression of the protein and showed that ENG1 expressed by the pHO-GAPDH-eng1-KanMX4-HO vector, in addition to its N-linked sites, is overglycosylated at its O-glycosylation sites compared with ENG1 expressed by the YEGAp/eng1 vector. It is likely that the O-glycosylated form of the A. niger ENG1 retains more stable activity during continuous cultivation of recombinant yeasts than the form that is only N-glycosylated. PMID:26125849

  20. The AngFus3 Mitogen-Activated Protein Kinase Controls Hyphal Differentiation and Secondary Metabolism in Aspergillus niger.

    PubMed

    Priegnitz, Bert-Ewald; Brandt, Ulrike; Pahirulzaman, Khomaizon A K; Dickschat, Jeroen S; Fleiner, Andr

    2015-06-01

    Adaptation to a changing environment is essential for the survival and propagation of sessile organisms, such as plants or fungi. Filamentous fungi commonly respond to a worsening of their growth conditions by differentiation of asexually or sexually produced spores. The formation of these specialized cell types is, however, also triggered as part of the general life cycle by hyphal age or density. Spores typically serve for dispersal and, therefore, translocation but can also act as resting states to endure times of scarcity. Eukaryotic differentiation in response to environmental and self-derived signals is commonly mediated by three-tiered mitogen-activated protein (MAP) kinase signaling cascades. Here, we report that the MAP kinase Fus3 of the black mold Aspergillus niger (AngFus3) and its upstream kinase AngSte7 control vegetative spore formation and secondary metabolism. Mutants lacking these kinases are defective in conidium induction in response to hyphal density but are fully competent in starvation-induced sporulation, indicating that conidiation in A. niger is triggered by various independent signals. In addition, the mutants exhibit an altered profile of volatile metabolites and secrete dark pigments into the growth medium, suggesting a dysregulation of the secondary metabolism. By assigning the AngFus3 MAP kinase pathway to the transduction of a potentially self-derived trigger, this work contributes to the unraveling of the intricate signaling networks controlling fungal differentiation. Moreover, our data further support earlier observations that differentiation and secondary metabolism are tightly linked in filamentous fungi. PMID:25888553

  1. Production and characterization of in planta transiently produced polygalacturanase from Aspergillus niger and its fusions with hydrophobin or ELP tags

    PubMed Central

    2014-01-01

    Background Pectinases play an important role in plant cell wall deconstruction and have potential in diverse industries such as food, wine, animal feed, textile, paper, fuel, and others. The demand for such enzymes is increasing exponentially, as are the efforts to improve their production and to implement their use in several industrial processes. The goal of this study was to examine the potential of producing polygalacturonase I from Aspergillus niger in plants and to investigate the effects of subcellular compartmentalization and protein fusions on its accumulation and activity. Results Polygalacturonase I from Aspergillus niger (AnPGI) was transiently produced in Nicotiana benthamiana by targeting it to five different cellular compartments: apoplast, endoplasmic reticulum (ER), vacuole, chloroplast and cytosol. Accumulation levels of 2.5%, 3.0%, and 1.9% of total soluble protein (TSP) were observed in the apoplast, ER, and vacuole, respectively, and specific activity was significantly higher in vacuole-targeted AnPGI compared to the same enzyme targeted to the ER or apoplast. No accumulation was found for AnPGI when targeted to the chloroplast or cytosol. Analysis of AnPGI fused with elastin-like polypeptide (ELP) revealed a significant increase in the protein accumulation level, especially when targeted to the vacuole where the protein doubles its accumulation to 3.6% of TSP, while the hydrophobin (HFBI) fusion impaired AnPGI accumulation and both tags impaired activity, albeit to different extents. The recombinant protein showed activity against polygalacturonic acid with optimum conditions at pH 5.0 and temperature from 30 to 50°C, depending on its fusion. In vivo analysis of reducing sugar content revealed a higher release of reducing sugars in plant tissue expressing recombinant AnPGI compared to wild type N. benthamiana leaves. Conclusion Our results demonstrate that subcellular compartmentalization of enzymes has an impact on both the target protein accumulation and its activity, especially in the case of proteins that undergo post-translational modifications, and should be taken into consideration when protein production strategies are designed. Using plants to produce heterologous enzymes for the degradation of a key component of the plant cell wall could reduce the cost of biomass pretreatment for the production of cellulosic biofuels. PMID:24970673

  2. Transcriptomic comparison of Aspergillus niger growing on two different sugars reveals coordinated regulation of the secretory pathway

    PubMed Central

    Jrgensen, Thomas R; Goosen, Theo; van den Hondel, Cees AMJJ; Ram, Arthur FJ; Iversen, Jens JL

    2009-01-01

    Background The filamentous fungus, Aspergillus niger, responds to nutrient availability by modulating secretion of various substrate degrading hydrolases. This ability has made it an important organism in industrial production of secreted glycoproteins. The recent publication of the A. niger genome sequence and availability of microarrays allow high resolution studies of transcriptional regulation of basal cellular processes, like those of glycoprotein synthesis and secretion. It is known that the activities of certain secretory pathway enzymes involved N-glycosylation are elevated in response to carbon source induced secretion of the glycoprotein glucoamylase. We have investigated whether carbon source dependent enhancement of protein secretion can lead to upregulation of secretory pathway elements extending beyond those involved in N-glycosylation. Results This study compares the physiology and transcriptome of A. niger growing at the same specific growth rate (0.16 h-1) on xylose or maltose in carbon-limited chemostat cultures. Transcription profiles were obtained using Affymetrix GeneChip analysis of six replicate cultures for each of the two growth-limiting carbon sources. The production rate of extracellular proteins per gram dry mycelium was about three times higher on maltose compared to xylose. The defined culture conditions resulted in high reproducibility, discriminating even low-fold differences in transcription, which is characteristic of genes encoding basal cellular functions. This included elements in the secretory pathway and central metabolic pathways. Increased protein secretion on maltose was accompanied by induced transcription of > 90 genes related to protein secretion. The upregulated genes encode key elements in protein translocation to the endoplasmic reticulum (ER), folding, N-glycosylation, quality control, and vesicle packaging and transport between ER and Golgi. The induction effect of maltose resembles the unfolded protein response (UPR), which results from ER-stress and has previously been defined by treatment with chemicals interfering with folding of glycoproteins or by expression of heterologous proteins. Conclusion We show that upregulation of secretory pathway genes also occurs in conditions inducing secretion of endogenous glycoproteins representing a more normal physiological state. Transcriptional regulation of protein synthesis and secretory pathway genes may thus reflect a general mechanism for modulation of secretion capacity in response to the conditional need for extracellular enzymes. PMID:19166577

  3. Effect of chemical modifications of cellulose on the activity of a cellulase from Aspergillus niger

    SciTech Connect

    Boyer, R.F.; Redmond, M.A.

    1983-05-01

    Five chemically modified forms of cellulose were prepared, characterized, and tested as substrates for a homogeneous glucanohydrolase from A. niger. The relative order of reactivity at pH 4.0 was DEAE = PEI more than benzyl DEAE more than cellulose more than P more than CM. This indicates that positively charged cellulose substrates are more susceptible to hydrolysis by the cellulase. This observation strengthens an earlier proposal that carboxyl groups on the enzyme are involved in substrate binding and catalytic action. Chemical modification is suggested as a method to increase the rate of enzymatic hydrolysis of cellulose, a process now in the commercial development stage. (Refs. 27).

  4. Effect of indigenous mycobiota on ochratoxin A production by Aspergillus carbonarius isolated from soil: ochratoxin in mixed cultures.

    PubMed

    Barberis, Carla L; Pena, Gabriela; Carranza, Cecilia; Magnoli, Carina E

    2014-02-01

    This study determined the biotic interaction between 30 non-toxigenic indigenous strains of Aspergillus niger aggregate, Aspergillus flavus, Trichoderma spp., Mucor spp., Cladosporium spp., Ulocladium spp., Curvularia spp., Absidia spp., Geotrichum spp. and Acremonium spp., isolated from soil destined for maize crops, with respect to their ability to prevent ochratoxin A (OTA) production by A. carbonarius on "in vitro" assay, on liquid and solid medium. OTA production was completely inhibited when A. carbonarius was inoculated in a interactive mixed culture with all A. niger aggregate strains assayed, a 80% of Trichoderma spp. strains, a 40% of Cladosporium spp. strains, Acremonium spp and Geotrichum spp; only one strain of A. flavus tested was able to completely inhibit the mycotoxin accumulation. OTA production increased when A. carbonarius ACS 8 was growing on liquid interactive mixed culture with Mucor spp strains. These results demonstrated that OTA production by Aspergillua carbonarius strain was significantly influenced by the presence of different non-toxigenic fungal strains when growing together on paired cultures. PMID:24155120

  5. Optimization of Acid Protease Production by Aspergillus niger I1 on Shrimp Peptone Using Statistical Experimental Design

    PubMed Central

    Siala, Rayda; Frikha, Fakher; Mhamdi, Samiha; Nasri, Moncef; Sellami Kamoun, Alya

    2012-01-01

    Medium composition and culture conditions for the acid protease production by Aspergillus niger I1 were optimized by response surface methodology (RSM). A significant influence of temperature, KH2PO4, and initial pH on the protease production was evaluated by Plackett-Burman design (PBD). These factors were further optimized using Box-Behnken design and RSM. Under the proposed optimized conditions, the experimental protease production (183.13 U mL−1) closely matched the yield predicted by the statistical model (172.57 U mL−1) with R2 = 0.914. Compared with the initial M1 medium on which protease production was 43.13 U mL−1, a successful and significant improvement by 4.25 folds was achieved in the optimized medium containing (g/L): hulled grain of wheat (HGW) 5.0; KH2PO4 1.0; NaCl 0.3; MgSO4(7H2O) 0.5; CaCl2 (7H2O) 0.4; ZnSO4 0.1; Na2HPO4 1.6; shrimp peptone (SP) 1.0. The pH was adjusted at 5 and the temperature at 30°C. More interestingly, the optimization was accomplished using two cheap and local fermentation substrates, HGW and SP, which may result in a significant reduction in the cost of medium constituents. PMID:22593695

  6. Immobilization of Aspergillus niger F7-02 Lipase in Polysaccharide Hydrogel Beads of Irvingia gabonensis Matrix

    PubMed Central

    Kareem, Safaradeen Olateju; Adio, Olayinka Quadri; Osho, Michael Bamitale

    2014-01-01

    The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v) Irvingia gabonensis powder, 15% (v/v) partially purified lipase, 2.5% (v/v) glutaraldehyde, and 3 : 1 (v/v) ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug−1 was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg−1 and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established. PMID:25614829

  7. Optimization of date syrup for enhancement of the production of citric acid using immobilized cells of Aspergillus niger

    PubMed Central

    Mostafa, Yasser S.; Alamri, Saad A.

    2012-01-01

    Date syrup as an economical source of carbohydrates and immobilized Aspergillus niger J4, which was entrapped in calcium alginate pellets, were employed for enhancing the production of citric acid. Maximum production was achieved by pre-treating date syrup with 1.5% tricalcium phosphate to remove heavy metals. The production of citric acid using a pretreated medium was 38.87% higher than an untreated one that consumed sugar. The appropriate presence of nitrogen, phosphate and magnesium appeared to be important in order for citric acid to accumulate. The production of citric acid and the consumed sugar was higher when using 0.1% ammonium nitrate as the best source of nitrogen. The production of citric acid increased significantly when 0.1g/l of KH2PO4 was added to the medium of date syrup. The addition of magnesium sulfate at the rate of 0.20g/l had a stimulating effect on the production of citric acid. Maximum production of citric acid was obtained when calcium chloride was absent. One of the most important benefits of immobilized cells is their ability and stability to produce citric acid under a repeated batch culture. Over four repeated batches, the production of citric acid production was maintained for 24days when each cycle continued for 144h. The results obtained in the repeated batch cultivation using date syrup confirmed that date syrup could be used as a medium for the industrial production of citric acid. PMID:23961184

  8. The Transcriptomic Signature of RacA Activation and Inactivation Provides New Insights into the Morphogenetic Network of Aspergillus niger

    PubMed Central

    Kwon, Min Jin; Nitsche, Benjamin M.; Arentshorst, Mark; Jrgensen, Thomas R.; Ram, Arthur F. J.; Meyer, Vera

    2013-01-01

    RacA is the main Rho GTPase in Aspergillus niger regulating polarity maintenance via controlling actin dynamics. Both deletion and dominant activation of RacA (RacG18V) provoke an actin localization defect and thereby loss of polarized tip extension, resulting in frequent dichotomous branching in the ?racA strain and an apolar growing phenotype for RacG18V. In the current study the transcriptomics and physiological consequences of these morphological changes were investigated and compared with the data of the morphogenetic network model for the dichotomous branching mutant ramosa-1. This integrated approach revealed that polar tip growth is most likely orchestrated by the concerted activities of phospholipid signaling, sphingolipid signaling, TORC2 signaling, calcium signaling and CWI signaling pathways. The transcriptomic signatures and the reconstructed network model for all three morphology mutants (?racA, RacG18V, ramosa-1) imply that these pathways become integrated to bring about different physiological adaptations including changes in sterol, zinc and amino acid metabolism and changes in ion transport and protein trafficking. Finally, the fate of exocytotic (SncA) and endocytotic (AbpA, SlaB) markers in the dichotomous branching mutant ?racA was followed, demonstrating that hyperbranching does not per se result in increased protein secretion. PMID:23894378

  9. Response surface optimization of medium components for citric acid production by Aspergillus niger NRRL 567 grown in peat moss.

    PubMed

    Barrington, Suzelle; Kim, Jin-Woo

    2008-01-01

    Aspergillus niger NRRL 567 was grown in an inert support material for citric acid production. Optimization of the medium components, including ethanol, methanol, phytate, olive oil and surfactant was carried out using "one-factor-at-a-time" and central composite design (CCD) methods. Optimization using "one-factor-at-a-time" was performed and the supplement of ethanol and methanol between 15 and 30 g/kg dry peat moss (DPM) enhanced citric acid production while higher levels than 30 g/kg DPM had an inhibitory effect on citric acid production at 48 and 72 h of incubation. Based on the results of "one-factor-at-a-time" optimization, phytate, olive oil and methanol were the selected additives to test the effect on citric acid production using CCD. The three variables were identified to have significant effects on citric acid production and the maximum citric acid production of 354.8 g/kg DPM was resulted from the combination of 19 g phytate/kg DPM, 49 g olive oil/kg DPM and 37 g methanol/kg DPM at 120 h. Maximum citric acid production in optimized condition by CCD represented about a 2.7-fold increase compared to that obtained from control before optimization. PMID:17267213

  10. Secretory Expression and Characterization of an Acidic Endo-Polygalacturonase Gene from Aspergillus niger SC323 in Saccharomyces cerevisiae.

    PubMed

    Zhou, Huoxiang; Li, Xi; Guo, Mingyue; Xu, Qingrui; Cao, Yu; Qiao, Dairong; Cao, Yi; Xu, Hui

    2015-07-01

    The endo-polygalacturonase gene (endo-pgaA) was cloned from DNA of Aspergillus niger SC323 using the cDNA synthesized by overlapping PCR, and successfully expressed in Saccharomyces cerevisiae EBY100 through fusing the ?-factor signal peptide of yeast. The full-length cDNA consists of 1,113 bp and encodes a protein of 370 amino acids with a calculated molecular mass of 38.8 kDa. After induction by galactose for 48 h, the activity of recombinant endo-PgaA in the culture supernatant can reach up to 1,448.48 U/mg. The recombinant protein was purified to homogeneity by ammonium sulfate precipitation and gel filtration column chromatography and subsequently characterized. The optimal pH and temperature of the purified recombinant enzyme were 5.0 and 50C, respectively. The Michaelis-Menten constant (Km) and maximal velocity (Vmax) of the enzyme for pectin were 88.54 ?mol/ml and 175.44 ?mol/mg/min, respectively. The enzyme activity was enhanced by Ca(2+), Cu(2+), and Na(+), and strongly inhibited by Pb(2+) and Mn(2+). The pectin hydrolysates were mainly galacturonic acid and other oligo-galacturonates. Therefore, these characteristics suggest that the recombinant endo-PgaA may be of potential use in the food and feed industries. PMID:25737122

  11. Characterization of a novel ?-cypermethrin-degrading Aspergillus niger YAT strain and the biochemical degradation pathway of ?-cypermethrin.

    PubMed

    Deng, Weiqin; Lin, Derong; Yao, Kai; Yuan, Huaiyu; Wang, Zhilong; Li, Jianlong; Zou, Likou; Han, Xinfeng; Zhou, Kang; He, Li; Hu, Xinjie; Liu, Shuliang

    2015-10-01

    Aspergillus niger YAT strain was obtained from Chinese brick tea (Collection number: CGMCC 10,568) and identified on the basis of morphological characteristics and internal transcribed spacer (ITS) sequence. The strain could degrade 54.83 % of ?-cypermethrin (?-CY; 50 mg L(-1)) in 7 days and 100 % of 3-phenoxybenzoic acid (3-PBA; 100 mg L(-1)) in 22 h. The half-lives of ?-CY and 3-PBA range from 3.573 to 11.748 days and from 5.635 to 12.160 h, respectively. The degradation of ?-CY and 3-PBA was further described using first-order kinetic models. The pathway and mechanism of ?-CY degraded by YAT were investigated by analyzing the degraded metabolites through high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). Relevant enzymatic activities and substrate utilization were also investigated. ?-CY degradation products were analyzed. Results indicated that YAT strain transformed ?-CY into 3-PBA. 3-PBA was then gradually transformed into permethric acid, protocatechuic acid, 3-hydroxy-5-phenoxy benzoic acid, gallic acid, and phenol gradually. The YAT strain can also effectively degrade these metabolites. The results indicated that YAT strain has potential applications in bioremediation of pyrethroid insecticide (PI)-contaminated environments and fermented food. PMID:26022858

  12. Antioxidant defense response induced by Trichoderma viride against Aspergillus niger Van Tieghem causing collar rot in groundnut (Arachis hypogaea L.).

    PubMed

    Gajera, H P; Katakpara, Zinkal A; Patel, S V; Golakiya, B A

    2016-02-01

    The study was conducted to examine the antioxidant enzymes induced by Trichoderma viride JAU60 as initial defense response during invasion of rot pathogen Aspergillus niger Van Tieghem in five groundnut varieties under pot culture. Seed treatment of T. viride JAU60 reduced 51-58% collar rot disease incidence in different groundnut varieties under pathogen infected soil culture. The activities of the antioxidant enzymes, viz., superoxide dismutase (SOD, EC 1.15.1.1), guaiacol peroxidase (GPX, EC 1.11.1.7) and ascorbate peroxidase (APX, EC 1.11.1.11), elevated in response to pathogen infection, in higher rate by tolerant varieties (J-11 and GG-2) compared with susceptible (GAUG-10, GG-13, GG-20) and further induced by T. viride treatment. Trichoderma treatment remarkably increased the 2.3 fold SOD, 5 fold GPX and 2.5 fold APX activities during disease development in tolerant varieties and the same was found about 1.2, 1.5 and 2.0 folds, respectively, in susceptible varieties. Overall, T. viride JAU60 treated seedlings (T3) witnessed higher activities of SOD (1.5 fold), GPX (3.25 fold) and APX (1.25 fold) than pathogen treatment (T2) possibly suggest the induction of antioxidant defense response by Trichoderma bio-controller to combat oxidative burst produced by invading pathogen. PMID:26620080

  13. Scale up of a novel tri-substrate fermentation for enhanced production of Aspergillus niger lipase for tallow hydrolysis.

    PubMed

    Edwinoliver, N G; Thirunavukarasu, K; Naidu, R B; Gowthaman, M K; Kambe, T Nakajima; Kamini, N R

    2010-09-01

    A novel tri-substrate fermentation (TSF) process was developed for the production of lipase from Aspergillus niger MTCC 2594 using agro-industrial residues, wheat bran (WB), coconut oil cake (COC) and an agro-product, wheat rawa (WR). The lipase activity was 628.7+/-13 U/g dry substrate (U/gds) at 30 degrees C and 96 h and growth studies indicated that addition of WR significantly augmented the biomass and lipase production. Scale up of lipase production at 100g and 3 kg (3 x 1 kg) tray-level batch fermentation resulted in 96% and 83.0% of enzyme activities, respectively, at 72 h. Maximum activity of 745.7+/-11U/gds was obtained, when fermented substrate was extracted in buffer containing 1% (w/v) sodium chloride and 0.5% (w/v) Triton X-100. Furthermore, the direct application of fermented substrate for tallow hydrolysis makes the process economical for industrial production of biofuel. PMID:20400303

  14. Gallic Acid Production with Mouldy Polyurethane Particles Obtained from Solid State Culture of Aspergillus niger GH1.

    PubMed

    Mata-Gmez, Marco; Mussatto, Solange I; Rodrguez, Raul; Teixeira, Jose A; Martinez, Jose L; Hernandez, Ayerim; Aguilar, Cristbal N

    2015-06-01

    Gallic acid production in a batch bioreactor was evaluated using as catalytic material the mouldy polyurethane solids (MPS) obtained from a solid-state fermentation (SSF) bioprocess carried out for tannase production by Aspergillus niger GH1 on polyurethane foam powder (PUF) with 5% (v/w) of tannic acid as inducer. Fungal biomass, tannic acid consumption and tannase production were kinetically monitored. SSF was stopped when tannase activity reached its maximum level. Effects of washing with distilled water and drying on the tannase activity of MPS were determined. Better results were obtained with dried and washed MPS retaining 84% of the tannase activity. Maximum tannase activity produced through SSF after 24h of incubation was equivalent to 130U/gS with a specific activity of 36U/mg. The methylgallate was hydrolysed (45%) in an easy, cheap and fast bioprocess (30min). Kinetic parameters of tannase self-immobilized on polyurethane particles were calculated to be 5mM and 04.1??10(-2)mM/min for K M and V max, respectively. Results demonstrated that the MPS, with tannase activity, can be successfully used for the production of the antioxidant gallic acid from methyl-gallate substrate. Direct use of PMS to produce gallic acid can be advantageous as no previous extraction of enzyme is required, thus reducing production costs. PMID:25920332

  15. Condition stabilization for Aspergillus niger FCBP-198 and its hyperactive mutants to yield high titres of alpha-amylase.

    PubMed

    Shafique, Sobiya; Bajwa, Rukhsana; Shafique, Shazia

    2010-01-01

    A number of substrates were tested for the cultivation of microorganisms to produce a host of enzymes. The effect of different substrates (wheat and rice straw, sugar cane waste, wood waste), incubation temperatures (20-40 degrees C), initial pH levels (3.5-9.0), incubation periods (0-72 hours) and nitrogen sources (ammonium sulfate, urea, peptone, yeast extract, sodium nitrate) on growth and alpha-amylase activity was studied for the native and mutant strains. Maximum enzyme activity was observed at 1.5% wheat straw for Aspergillus niger FCBP-198 and An-Ch-4.7 and at 2% wheat straw for An-UV-5.6, with sodium nitrate as a principle nitrogen source. The optimum temperature for maximum enzyme activity was 30 degrees C for the parental strain, while An-UV-5.6 and An-Ch-4.7 thrived well at 32.5 degrees C. The best conditions of pH and incubation duration were 4.5 and 48 hours, respectively, for all the strains. Mass production under preoptimized growth conditions demonstrated the suitability of wheat straw for swift mycelial colonization and viability. PMID:20734811

  16. Production of high concentrations of ethanol from inulin by simultaneous saccharification and fermentation using Aspergillus niger and Saccharomyces cerevisiae.

    PubMed Central

    Ohta, K; Hamada, S; Nakamura, T

    1993-01-01

    Pure nonhydrolyzed inulin was directly converted to ethanol in a simultaneous saccharification and fermentation process. An inulinase-hyperproducing mutant, Aspergillus niger 817, was grown in a submerged culture at 30 degrees C for 5 days. The inulin-digestive liquid culture (150 ml) was supplemented with 45 g of inulin, 0.45 g of (NH4)2SO4, and 0.15 g of KH2PO4. The medium (pH 5.0) was inoculated with an ethanol-tolerant strain, Saccharomyces cerevisiae 1200, and fermentation was conducted at 30 degrees C. An additional 20 g of inulin was added to the culture after 15 h of fermentation. S. cerevisiae 1200 utilized 99% of the 65 g of inulin during the fermentation, and produced 20.4 and 21.0% (vol/vol) ethanol from chicory and dahlia inulins, respectively, within 3 days of fermentation. The maximum volumetric productivities of ethanol were 6.2 and 6.0 g/liter/h for chicory and dahlia inulins, respectively. The conversion efficiency of inulin to ethanol was 83 to 84% of the theoretical ethanol yield. PMID:8481000

  17. Biotransformation of natural compounds: unexpected thio conjugation of Sch-642305 with 3-mercaptolactate catalyzed by Aspergillus niger ATCC 16404 cells.

    PubMed

    Adelin, Emilie; Martin, Marie-Thrse; Bricot, Marie-Franoise; Cortial, Sylvie; Retailleau, Pascal; Ouazzani, Jamal

    2012-12-01

    Sch-642305 is produced by the endophytic fungi Phomopsis sp. CMU-LMA and exhibits both antimicrobial and cytotoxic activities. The incubation of Sch-642305 with Aspergillus niger ATCC 16404 resting cells leads to two unexpected thio conjugates. Compound (1) is formed by the addition of the cysteine metabolite 3-mercaptolactate to the double bond of Sch-642305. Compound (1) undergoes an intramolecular rearrangement to give compound (2), which contains two rings: a five-membered hydroxylactone ring and a five-membered thiophene ring. The absolute configuration of compound (1) is similar to that of the parent compound, but the configuration of the mercaptolactate side-chain was not determined. The absolute configuration of compound (2) was deduced from the crystal structure and confirmed by the anomal effect of the sulfur atom. To the best of our knowledge, this is the first time such a conjugation rearrangement reactions were observed. The biological significance and the reaction mechanisms are discussed. Compound (1) exhibits a weak antimicrobial activity against Gram-positive bacteria, whereas derivatives (1) and (2) showed an IC?? of 1 and 1.2 ?M, respectively, against colonic epithelial cancer cells. PMID:22975164

  18. Synthesis of fructooligosaccharides from Aspergillus niger commercial inulinase immobilized in montmorillonite pretreated in pressurized propane and LPG.

    PubMed

    de Oliveira Kuhn, Graciele; Rosa, Clarissa Dalla; Silva, Marceli Fernandes; Treichel, Helen; de Oliveira, Dbora; Oliveira, J Vladimir

    2013-02-01

    Commercial inulinase from Aspergillus niger was immobilized in montmorillonite and then treated in pressurized propane and liquefied petroleum gas (LPG). Firstly, the effects of system pressure, exposure time, and depressurization rate, using propane and LPG, on enzymatic activity were evaluated through central composite design 2. Residual activities of 145.1 and 148.5% were observed for LPG (30 bar, 6 h, and depressurization rate of 20 bar?min?) and propane (270 bar, 1 h, and depressurization rate of 100 bar?min?), respectively. The catalysts treated at these conditions in both fluids were then used for the production of fructooligosaccharides (FOS) using sucrose and inulin as substrates in aqueous and organic systems. The main objective of this step was to evaluate the yield and productivity in FOS, using alternatives for enhancing enzyme activity by means of pressurized fluids and also using low-cost supports for enzyme immobilization, aiming at obtaining a stable biocatalyst to be used for synthesis reactions. Yields of 18% were achieved using sucrose as substrate in aqueous medium, showing the potential of this procedure, hence suggesting a further optimization step to increase the process yield. PMID:23271628

  19. Immobilization of Aspergillus niger lipase on chitosan-coated magnetic nanoparticles using two covalent-binding methods.

    PubMed

    Osuna, Yolanda; Sandoval, José; Saade, Hened; López, Raúl G; Martinez, José L; Colunga, Edith M; de la Cruz, Gabriela; Segura, Elda P; Arévalo, Fernando J; Zon, María A; Fernández, Héctor; Ilyina, Anna

    2015-08-01

    Aspergillus niger lipase immobilization by covalent binding on chitosan-coated magnetic nanoparticles (CMNP), obtained by one-step co-precipitation, was studied. Hydroxyl and amino groups of support were activated using glycidol and glutaraldehyde, respectively. Fourier transform infrared spectrometry, high-resolution transmission electron microscopy and thermogravimetric analysis confirmed reaction of these coupling agents with the enzyme and achievement of a successful immobilization. The derivatives showed activities of 309.5 ± 2.0 and 266.2 ± 2.8 U (g support)(-1) for the CMNP treated with glutaraldehyde and with glycidol, respectively. Immobilization enhanced the enzyme stability against changes of pH and temperature, compared to free lipase. Furthermore, the kinetic parameters K m and V max were determined for the free and immobilized enzyme. K m value quantified for enzyme immobilized by means of glutaraldehyde was 1.7 times lowers than for free lipase. High storage stability during 50 days was observed in the immobilized derivatives. Finally, immobilized derivatives retained above 80% of their initial activity after 15 hydrolytic cycles. The immobilized enzyme can be applied in various biotechnological processes involving magnetic separation. PMID:25759161

  20. Probing role of key residues in the divergent evolution of Yarrowia lipolytica lipase 2 and Aspergillus niger eruloyl esterase A.

    PubMed

    Wang, Guilong; Liu, Zimin; Xu, Li; Zhang, Houjin; Yan, Yunjun

    2015-09-01

    Yarrowia lipolytica lipase 2 (YLLip2) and Aspergillus niger feruloyl esterase A (AnFaeA) are enzymes of similar structures but with different functions. They are both classified into the same homologous family in Lipase Engineering Database (LED). The major difference between the two enzymes is that YLLip2 exhibits interfacial activity while AnFaeA does not. In order to better understand the interfacial activation mechanisms of YLLip2, structure guided site-directed mutagenesis were performed, mutants were constructed, kinetics parameters and lipase properties were detected. Mutant enzymes showed enhanced catalytic efficiency towards p-nitrophenyl butyrin (pNPB) but their catalytic efficiency decreased towards p-nitrophenyl palmitate (pNPP), their catalysis behavior was more close to feruloyl esterase. Moreover, the mutant enzymes exhibited enhanced thermostability compared with their wild type. These results indicate that I100 and F129 are probably cut-off point of divergent functions between the two enzymes during evolution. PMID:26302844

  1. Determination of the reaction yield during biotransformation of the volatile and chemically unstable compound beta-ionone by aspergillus niger

    PubMed

    Grivel; Larroche; Gros

    1999-07-01

    Biotransformation of beta-ionone by Aspergillus niger IFO 8541 was a complex system, due to the low precursor solubility in water (0.88 mol/m(3)) which gave a two-phase liquid system, its high volatility (vapor pressure 7.2 Pa), and its poor chemical stability. A dynamic model, considering transfers between organic, aqueous, and gas layers, was established. It also took into account the decrease in organic layer area exchange during a process, due to progressive precursor disappearance. Its solving needed separate determination of two parameters. The first-order kinetic constant for chemical degradation, K(1), was estimated from side experiments involving a model system at thermodynamic equilibrium; its value was found to be close to 4.17 x 10(-)(6) s(-)(1). The volumetric transfer coefficient between gas and aqueous phase was estimated by analogy with results obtained for oxygen transfer. Results obtained demonstrated high liquid-gas transfer rates, while liquid-liquid transfers were severely limited. These data were then used to estimate the true yield of a biotransformation experiment, which was found to be close to unity. PMID:10441361

  2. Characterization of ?-Glucosidase Produced by Aspergillus niger under Solid-State Fermentation and Partially Purified Using MANAE-Agarose

    PubMed Central

    Borges, Diogo G.; Tardioli, Paulo W.; Farinas, Cristiane S.

    2014-01-01

    ?-Glucosidase (BGL) is a hydrolytic enzyme with specificity for a wide variety of glycoside substrates, being an enzyme with a large range of biotechnological applications. However, enzyme properties can be different depending both on the microorganism and the cultivation procedure employed. Therefore, in order to explore potential biocatalytical applications of novel enzymes, their characterization is essential. In this work, a BGL synthesized by a selected strain of Aspergillus niger cultivated under solid-state fermentation (SSF) was partially purified and fully characterized in terms of optimum pH, temperature, and thermostability. The single-step purification using MANAE-agarose in a chromatographic column yielded an enzyme solution with specific activity (17.1?IU/mg protein) adequate for the characterization procedures. Electrophoresis SDS-PAGE and size-exclusion chromatography analysis resulted in an estimated molecular mass of 60?kDa. Higher enzyme activities were found in the range between 40 and 65C and between pH 4 and 5.5, indicating an interesting characteristic for application in the hydrolysis of lignocellulosic biomass for biofuels production. Thermostability studies of purified BGL resulted in half-lives at 37C of 56.3?h and at 50C of 5.4?h. These results provide support for further studies of this enzyme towards revealing its potential biotechnological applications. PMID:24940510

  3. Study of a High-Yield Cellulase System Created by Heavy-Ion Irradiation-Induced Mutagenesis of Aspergillus niger and Mixed Fermentation with Trichoderma reesei.

    PubMed

    Wang, Shu-Yang; Jiang, Bo-Ling; Zhou, Xiang; Chen, Ji-Hong; Li, Wen-Jian; Liu, Jing; Hu, Wei; Xiao, Guo-Qing; Dong, Miao-Yin; Wang, Yu-Chen

    2015-01-01

    The aim of this study was to evaluate and validate the efficiency of 12C6+ irradiation of Aspergillus niger (A. niger) or mutagenesis via mixed Trichoderma viride (T. viride) culturing as well as a liquid cultivation method for cellulase production via mixed Trichoderma reesei (T. reesei) and A. niger culture fermentation. The first mutagenesis approach was employed to optimize yield from a cellulase-producing strain via heavy-ion mutagenesis and high-throughput screening, and the second was to effectively achieve enzymatic hydrolysis of cellulase from a mixed culture of mutant T. viride and A. niger. We found that 12C6+-ion irradiation induced changes in cellulase biosynthesis in A. niger but had no effect on the time course of the synthesis. It is notable that the exoglucanases (CBH) activities of A. niger strains H11-1 and H differed (6.71 U/mL vs. 6.01 U/mL) and were significantly higher than that of A. niger mutant H3-1. Compared with strain H, the filter paper assay (FPA), endoglucanase (EG) and ?-glucosidase (BGL) activities of mutant strain H11-1 were increased by 250.26%, 30.26% and 34.91%, respectively. A mixed culture system was successfully optimized, and the best ratio of T. reesei to A. niger was 5:1 for 96 h with simultaneous inoculation. The BGL activity of the mixed culture increased after 72 h. At 96 h, the FPA and BGL activities of the mixed culture were 689.00 and 797.15 U/mL, respectively, significantly higher than those of monocultures, which were 408.70 and 646.98 U/mL for T. reesei and 447.29 and 658.89 U/mL for A. niger, respectively. The EG activity of the mixed culture was 2342.81 U/mL, a value that was significantly higher than that of monocultures at 2206.57 U/mL for T. reesei and 1727.62 U/mL for A. niger. In summary, cellulose production and hydrolysis yields were significantly enhanced by the proposed combination scheme. PMID:26656155

  4. Study of a High-Yield Cellulase System Created by Heavy-Ion Irradiation-Induced Mutagenesis of Aspergillus niger and Mixed Fermentation with Trichoderma reesei

    PubMed Central

    Chen, Ji-Hong; Li, Wen-Jian; Liu, Jing; Hu, Wei; Xiao, Guo-Qing; Dong, Miao-Yin; Wang, Yu-Chen

    2015-01-01

    The aim of this study was to evaluate and validate the efficiency of 12C6+ irradiation of Aspergillus niger (A. niger) or mutagenesis via mixed Trichoderma viride (T. viride) culturing as well as a liquid cultivation method for cellulase production via mixed Trichoderma reesei (T. reesei) and A. niger culture fermentation. The first mutagenesis approach was employed to optimize yield from a cellulase-producing strain via heavy-ion mutagenesis and high-throughput screening, and the second was to effectively achieve enzymatic hydrolysis of cellulase from a mixed culture of mutant T. viride and A. niger. We found that 12C6+-ion irradiation induced changes in cellulase biosynthesis in A. niger but had no effect on the time course of the synthesis. It is notable that the exoglucanases (CBH) activities of A. niger strains H11-1 and H differed (6.71 U/mL vs. 6.01 U/mL) and were significantly higher than that of A. niger mutant H3-1. Compared with strain H, the filter paper assay (FPA), endoglucanase (EG) and β-glucosidase (BGL) activities of mutant strain H11-1 were increased by 250.26%, 30.26% and 34.91%, respectively. A mixed culture system was successfully optimized, and the best ratio of T. reesei to A. niger was 5:1 for 96 h with simultaneous inoculation. The BGL activity of the mixed culture increased after 72 h. At 96 h, the FPA and BGL activities of the mixed culture were 689.00 and 797.15 U/mL, respectively, significantly higher than those of monocultures, which were 408.70 and 646.98 U/mL for T. reesei and 447.29 and 658.89 U/mL for A. niger, respectively. The EG activity of the mixed culture was 2342.81 U/mL, a value that was significantly higher than that of monocultures at 2206.57 U/mL for T. reesei and 1727.62 U/mL for A. niger. In summary, cellulose production and hydrolysis yields were significantly enhanced by the proposed combination scheme. PMID:26656155

  5. Characterization of species of the Aspergillus section Nigri from corn field isolates co-infected with Aspergillus flavus/parasiticus species and the potential for ochratoxin A production.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Members of the Aspergillus section Nigri, known as black-spored aspergilli, can contaminate several substrates including maize. Although some species within the group can produce plant disease symptoms such as black mold in onions and maize ear rot, the main concern with A. niger aggregate contamina...

  6. Trehalose synthesis in Aspergillus niger: characterization of six homologous genes, all with conserved orthologs in related species

    PubMed Central

    2014-01-01

    Background The disaccharide trehalose is a major component of fungal spores and is released upon germination. Moreover, the sugar is well known for is protective functions, e.g. against thermal stress and dehydration. The properties and synthesis of trehalose have been well investigated in the bakers’ yeast Saccharomyces cerevisiae. In filamentous fungi, such knowledge is limited, although several gene products have been identified. Results Using Aspergillus niger as a model fungus, the aim of this study was to provide an overview of all genes involved in trehalose synthesis. This fungus has three potential trehalose-6-phosphate synthase encoding genes, tpsA-C, and three putative trehalose phosphate phosphatase encoding genes, tppA-C, of which two have not previously been identified. Expression of all six genes was confirmed using real-time PCR, and conserved orthologs could be identified in related Aspergilli. Using a two-hybrid approach, there is a strong indication that four of the proteins physically interact, as has previously been shown in S. cerevisiae. When creating null mutants of all the six genes, three of them, ΔtpsA, ΔtppA and ΔtppB, had lower internal trehalose contents. The only mutant with a pronounced morphological difference was ΔtppA, in which sporulation was severely reduced with abnormal conidiophores. This was also the only mutant with accumulated levels of trehalose-6-phosphate, indicating that the encoded protein is the main phosphatase under normal conditions. Besides ΔtppA, the most studied deletion mutant in this work was ΔtppB. This gene encodes a protein conserved in filamentous Ascomycota. The ΔtppB mutant displayed a low, but not depleted, internal trehalose content, and conidia were more susceptible to thermal stress. Conclusion A. niger contains at least 6 genes putatively involved in trehalose synthesis. Gene expressions related to germination have been quantified and deletion mutants characterized: Mutants lacking tpsA, tppA or tppB have reduced internal trehalose contents. Furthermore, tppA, under normal conditions, encodes the functional trehalose-6-phosphate-phosphatase. PMID:24725382

  7. Customization of Aspergillus niger morphology through addition of talc micro particles.

    PubMed

    Wucherpfennig, Thomas; Lakowitz, Antonia; Driouch, Habib; Krull, Rainer; Wittmann, Christoph

    2012-01-01

    The filamentous fungus A. niger is a widely used strain in a broad range of industrial processes from food to pharmaceutical industry. One of the most intriguing and often uncontrollable characteristics of this filamentous organism is its complex morphology. It ranges from dense spherical pellets to viscous mycelia. Various process parameters and ingredients are known to influence fungal morphology. Since optimal productivity correlates strongly with a specific morphological form, the fungal morphology often represents the bottleneck of productivity in industrial production. A straight forward and elegant approach to precisely control morphological shape is the addition of inorganic insoluble micro particles (like hydrous magnesium silicate, aluminum oxide or titanium silicate oxide) to the culture medium contributing to increased enzyme production. Since there is an obvious correlation between micro particle dependent morphology and enzyme production it is desirable to mathematically link productivity and morphological appearance. Therefore a quantitative precise and holistic morphological description is targeted. Thus, we present a method to generate and characterize micro particle dependent morphological structures and to correlate fungal morphology with productivity which possibly contributes to a better understanding of the morphogenesis of filamentous microorganisms. The recombinant strain A. niger SKAn1015 is cultivated for 72 h in a 3 L stirred tank bioreactor. By addition of talc micro particles in concentrations of 1 g/L, 3 g/L and 10 g/L prior to inoculation a variety of morphological structures is reproducibly generated. Sterile samples are taken after 24, 48 and 72 hours for determination of growth progress and activity of the produced enzyme. The formed product is the high-value enzyme ?-fructofuranosidase, an important biocatalyst for neo-sugar formation in food or pharmaceutical industry, which catalyzes among others the reaction of sucrose to glucose. Therefore, the quantification of glucose after adding sucrose implies the amount of produced ?-fructofuranosidase. Glucose quantification is made by a GOD/POD-Assay, which is modified for high-throughput analysis in 96-well micro titer plates. Fungal morphology after 72 hours is examined by microscope and characterized by digital image analysis. In doing so, particle shape factors for fungal macro morphology like Feret's diameter, projected area, perimeter, circularity, aspect ratio, roundness und solidity are calculated with the open source image processing program ImageJ. Relevant parameters are combined to a dimensionless Morphology number (Mn), which enables a comprehensive characterization of fungal morphology. The close correlation of the Morphology number and productivity are highlighted by mathematical regression. PMID:22453998

  8. Displaying Candida antarctica lipase B on the cell surface of Aspergillus niger as a potential food-grade whole-cell catalyst.

    PubMed

    Pan, Zhi-You; Yang, Zhi-Ming; Pan, Li; Zheng, Sui-Ping; Han, Shuang-Yan; Lin, Ying

    2014-04-01

    Aspergillus niger is a recognized workhorse used to produce food processing enzymes because of its extraordinarily high protein-producing capacity. We have developed a new cell surface display system de novo in A. niger using expression elements from generally recognized as safe certified microorganisms. Candida antarctica lipase B (CALB), a widely used hydrolase, was fused to an endogenous cell wall mannoprotein, CwpA, and functionally displayed on the cell surface. Localization of CALB was confirmed by enzymatic assay and immunofluorescence analysis using laser scanning confocal microscopy. After induction by maltose for 45h, the hydrolytic activity and synthesis activity of A. niger mycelium-surface displayed CALB (AN-CALB) reached 400 and 240U/g dry cell, respectively. AN-CALB was successfully used as a whole-cell catalyst for the enzymatic production of ethyl esters from a series of fatty acids of different chain lengths and ethanol. In a solvent-free system, AN-CALB showed great synthetic activity and afforded high substrate mole conversions, which amounted to 87% for ethyl hexanoate after 2h, 89% for ethyl laurate after 2h, and 84% for ethyl stearate after 3h. These results suggested that CwpA can act as an efficient anchoring motif for displaying enzyme on A. niger, and AN-CALB is a robust, green, and cost-effective alternative food-grade whole-cell catalyst to commercial lipase. PMID:24519503

  9. Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.

    PubMed

    Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo

    2014-08-01

    Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum. PMID:24803238

  10. Overexpression of the Aspergillus niger GatA transporter leads to preferential use of D-galacturonic acid over D-xylose

    PubMed Central

    2014-01-01

    Pectin is a structural heteropolysaccharide of the primary cell walls of plants and as such is a significant fraction of agricultural waste residues that is currently insufficiently used. Its main component, D-galacturonic acid, is an attractive substrate for bioconversion. The complete metabolic pathway is present in the genome of Aspergillus niger, that is used in this study. The objective was to identify the D-galacturonic acid transporter in A. niger and to use this transporter to study D-galacturonic acid metabolism. We have functionally characterized the gene An14g04280 that encodes the D-galacturonic acid transporter in A. niger. In a mixed sugar fermentation it was found that the An14g04280 overexpression strain, in contrast to the parent control strain, has a preference for D-galacturonic acid over D-xylose as substrate. Overexpression of this transporter in A. niger resulted in a strong increase of D-galacturonic acid uptake and induction of the D-galacturonic acid reductase activity, suggesting a metabolite controlled regulation of the endogenous D-galacturonic acid catabolic pathway. PMID:25177540

  11. Aspergillus niger P6 and Rhodotorula mucilaginosa CH4 used for olive mill wastewater (OMW) biological treatment in single pure and successive cultures.

    PubMed

    Jarboui, Raja; Magdich, Salwa; Ayadi, Raja Jarboui; Gargouri, Ali; Gharsallah, Nji; Ammar, Emna

    2013-01-01

    The aim of this study was to investigate the Rhodotorula mucilaginosa CH4 and Aspergillus niger P6 abilities to purify olive mill wastewater (OMW) in single pure and mixed cultures during the treatment. Both fungi were molecularly identified. OMW was used at five dilutions from 5% to 30% with chemical oxygen demand (COD) ranging from 11,600 to 24,600 mg L(-1). Firstly, each fungus was used separately, then they were successively used to treat the OMW. In single pure culture, A. niger showed a better efficiency in OMW purification than R. mucilaginosa. Furthermore, when successively used, the two studied strains exhibited improvements in the decrease of COD, polyphenolic compounds concentration and effluent colour. COD removals were 95.68-56.71% by R. mucilaginosa and 98.02-69.51% by A. niger for OMW dilutions varying from 5% to 30%. Both strains showed an important polyphenolic compounds removal of 83-45% by R. mucilaginosa and 94-58% by A. niger, in accordance with the OMW COD initially used. The COD and phenolic compound removals fitted simple equation models, with high regression coefficients. The strains' growth kinetics decreased according to the OMW concentration, but, when successively used, fungal growth was improved, allowing efficient effluent treatment. PMID:23837312

  12. A high-throughput method for screening of Aspergillus niger mutants with high transglycosylation activity by detecting non-fermentable reducing sugar.

    PubMed

    Chen, Gui-Guang; Li, Wei; Zhang, Yun-Kai; Qin, Yong-Ling; Wu, Kong-Yang; Liang, Zhi-Qun

    2011-06-01

    A novel high-throughput method was established for rapid screening of large numbers of Aspergillus niger mutants with high transglucosylation activity by exploiting that yeast can hardly hydrolyze isomaltooligosaccharides (IMO). Supernatants of A. niger fermentation were incubated with Saccharomyces cerevisiae to remove glucose and maltose, and the remaining non-reducing sugars, which is positively correlated with the amount of IMO, the products of transglucosylation reaction, were used as indicator of transglucosidase activity of A. niger and examined by dinitrosalicylic acid assay. Using this method, 15 stains that could convert liquefied cassava starch to IMO more efficiently were selected from 8721 A. niger mutants. Among them, mutant C-6181 strain had transglycosidase activity of 4.61 U/ml (increased by 122% compared to its parental strain) and IMO yield of 83.7%. Taking together, the method is easy, simple, efficient and cheap, and has great application potential in selection of transglucosidase-producing strains used in industrial IMO fermentation. PMID:25187152

  13. Mapping N-linked Glycosylation Sites in the Secretome and Whole Cells of Aspergillus niger Using Hydrazide Chemistry and Mass Spectrometry

    SciTech Connect

    Wang, Lu; Aryal, Uma K.; Dai, Ziyu; Mason, Alisa C.; Monroe, Matthew E.; Tian, Zhixin; Zhou, Jianying; Su, Dian; Weitz, Karl K.; Liu, Tao; Camp, David G.; Smith, Richard D.; Baker, Scott E.; Qian, Weijun

    2012-01-01

    Protein glycosylation is known to play an essential role in both cellular functions and the secretory pathways; however, little information is available on the dynamics of glycosylated N-linked glycosites of fungi. Herein we present the first extensive mapping of glycosylated N-linked glycosites in industrial strain Aspergillus niger by applying an optimized solid phase enrichment of glycopeptide protocol using hydrazide modified magnetic beads. The enrichment protocol was initially optimized using mouse plasma and A. niger secretome samples, which was then applied to profile N-linked glycosites from both the secretome and whole cell lysates of A. niger. A total of 847 unique N-linked glycosites and 330 N-linked glycoproteins were confidently identified by LC-MS/MS. Based on gene ontology analysis, the identified N-linked glycoproteins in the whole cell lysate were primarily localized in the plasma membrane, endoplasmic reticulum, golgi apparatus, lysosome, and storage vacuoles. The identified N-linked glycoproteins are involved in a wide range of biological processes including gene regulation and signal transduction, protein folding and assembly, protein modification and carbohydrate metabolism. The extensive coverage of glycosylated N-linked glycosites along with identification of partial N-linked glycosylation in those enzymes involving in different biochemical pathways provide useful information for functional studies of N-linked glycosylation and their biotechnological applications in A. niger.

  14. Trancriptional landscape of Aspergillus niger at breaking of conidial dormancy revealed by RNA-sequencing

    PubMed Central

    2013-01-01

    Background Genome-wide analysis was performed to assess the transcriptional landscape of germinating A. niger conidia using both next generation RNA-sequencing and GeneChips. The metabolism of storage compounds during conidial germination was also examined and compared to the transcript levels from associated genes. Results The transcriptome of dormant conidia was shown to be highly differentiated from that of germinating conidia and major changes in response to environmental shift occurred within the first hour of germination. The breaking of dormancy was associated with increased transcript levels of genes involved in the biosynthesis of proteins, RNA turnover and respiratory metabolism. Increased transcript levels of genes involved in metabolism of nitrate at the onset of germination implies its use as a source of nitrogen. The transcriptome of dormant conidia contained a significant component of antisense transcripts that changed during germination. Conclusion Dormant conidia contained transcripts of genes involved in fermentation, gluconeogenesis and the glyoxylate cycle. The presence of such transcripts in dormant conidia may indicate the generation of energy from non-carbohydrate substrates during starvation-induced conidiation or for maintenance purposes during dormancy. The immediate onset of metabolism of internal storage compounds after the onset of germination, and the presence of transcripts of relevant genes, suggest that conidia are primed for the onset of germination. For some genes, antisense transcription is regulated in the transition from resting conidia to fully active germinants. PMID:23577966

  15. Bioconversion of oil palm frond by Aspergillus niger to enhances it's fermentable sugar production.

    PubMed

    Lim, Sheh-Hong; Ibrahim, Darah

    2013-09-15

    The aim of this study was to develop an economical bioprocess to produce the fermentable sugars at laboratory scales Using Oil Palm Frond (OPF) as substrate in Solid State Fermentation (SSF). OPF waste generated by oil palm plantations is a major problem in terms of waste management. However, this lignocellulosic waste material is a cheap source of cellulose. We used OPF as substrate to produce fermentable sugars. The high content of cellulose in OPF promises the high fermentable sugars production in SSF. Saccharification of OPF waste by A. niger USMAI1 generates fermentable sugars and was evaluated through a solid state fermentation. Physical parameters, e.g., inoculum size, initial substrate moisture, initial pH, incubation temperature and the size of substrate were optimized to obtain the maximum fermentable sugars from oil palm fronds. Up to 77 mg of fermentable sugars per gram substrate was produced under the optimal physical parameter conditions. Lower productivity of fermentable sugars, 32 mg fermentable sugars per gram substrate was obtained under non optimized conditions. The results indicated that about 140.6% increase in fermentable sugar production after optimization of the physical parameters. Glucose was the major end component amongst the fermentable sugars obtained. This study indicated that under optimum physical parameter conditions, the OPF waste can be utilized to produce fermentable sugars which then convert into other products such as alcohol. PMID:24502148

  16. Application of response surface methodology for optimization of polygalacturonase production by Aspergillus niger.

    PubMed

    Yadav, Kaushlesh K; Garg, Neelima; Kumar, Devendra; Kumar, Sanjay; Singh, Achal; Muthukumar, M

    2015-01-01

    Polygalacturonase (PG) degrades pectin into D-galacturonic acid monomers and is used widely in food industry especially for juice clarification. In the present study,. fermentation conditions for polygalacturonase production by Asgergillus niger NAIMCCF-02958, using mango peel as substrate, were optimized using the 2(3) factorial design with central composite rotatable experimental design (CCRD) of response surface methodology (RSM). The maximum PG activity 723.66 U g(-1) was achieved under pH 4.0, temperature 30 degrees C and 2% inoculum by response surface curve. The experimental value of PG activity wkas higher 607.65 U g(-1) than the predicted value 511.75 U g(-1). Under the proposed optimized conditions, the determination coefficient (R2) was equal to 0.66 indicating that the model could explain 66% of the total variation as well as establish the relationship between the variables and the responses. ANOVA analysis and the three dimensional plots also confirmed interactions among the parameters. PMID:26536801

  17. Glucoamylase overexpression in Aspergillus niger: molecular genetic analysis of strains containing multiple copies of the glaA gene.

    PubMed

    Verdoes, J C; Punt, P J; Schrickx, J M; van Verseveld, H W; Stouthamer, A H; van den Hondel, C A

    1993-03-01

    A strategy, based on the usage of the amdS selection marker and a cosmid vector containing four copies of the glucoamylase gene (glaA), was developed to obtain glucoamylase (GLA)-overproducing A. niger strains. With this strategy, fungal strains carrying up to 200 copies of the glaA gene could be isolated at a relatively high frequency. In each transformant analysed, integration occurred in a single chromosome. A significant increase in the extracellular GLA production was observed in most of the transformants carrying multiple copies of the glaA gene. Further analysis showed that the amount of GLA that is produced was not proportional to the number of glaA copies in these transformants. However, the level of GLA production clearly correlated with the amount of glaA mRNA produced in these transformants. From these results it is concluded that GLA production is limited at the level of transcription. PMID:8513339

  18. Submerged Conidiation and Product Formation by Aspergillus niger at Low Specific Growth Rates Are Affected in Aerial Developmental Mutants ▿

    PubMed Central

    Jørgensen, Thomas R.; Nielsen, Kristian F.; Arentshorst, Mark; Park, JooHae; van den Hondel, Cees A.; Frisvad, Jens C.; Ram, Arthur F.

    2011-01-01

    Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (ΔfwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B2, B4, and B6 were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ΔfwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance. PMID:21652743

  19. The role of carbon starvation in the induction of enzymes that degrade plant-derived carbohydrates in Aspergillus niger

    PubMed Central

    van Munster, Jolanda M.; Daly, Paul; Delmas, Stéphane; Pullan, Steven T.; Blythe, Martin J.; Malla, Sunir; Kokolski, Matthew; Noltorp, Emelie C.M.; Wennberg, Kristin; Fetherston, Richard; Beniston, Richard; Yu, Xiaolan; Dupree, Paul; Archer, David B.

    2014-01-01

    Fungi are an important source of enzymes for saccharification of plant polysaccharides and production of biofuels. Understanding of the regulation and induction of expression of genes encoding these enzymes is still incomplete. To explore the induction mechanism, we analysed the response of the industrially important fungus Aspergillus niger to wheat straw, with a focus on events occurring shortly after exposure to the substrate. RNA sequencing showed that the transcriptional response after 6 h of exposure to wheat straw was very different from the response at 24 h of exposure to the same substrate. For example, less than half of the genes encoding carbohydrate active enzymes that were induced after 24 h of exposure to wheat straw, were also induced after 6 h exposure. Importantly, over a third of the genes induced after 6 h of exposure to wheat straw were also induced during 6 h of carbon starvation, indicating that carbon starvation is probably an important factor in the early response to wheat straw. The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides. We show, using proteomics, that carbon-starved cultures indeed release CAZymes with predicted activity on plant polysaccharides. Analysis of the enzymatic activity and the reaction products, indicates that these proteins are enzymes that can degrade various plant polysaccharides to generate both known, as well as potentially new, inducers of CAZymes. PMID:24792495

  20. Analysis of the role of the Spitzenkrper in fungal morphogenesis by computer simulation of apical branching in Aspergillus?niger

    PubMed Central

    Reynaga-Pea, Cristina G.; Gierz, Gerhard; Bartnicki-Garcia, Salomon

    1997-01-01

    High-resolution video microscopy, image analysis, and computer simulation were used to study the role of the Spitzenkrper (Spk) in apical branching of ramosa-1, a temperature-sensitive mutant of Aspergillus niger. A shift to the restrictive temperature led to a cytoplasmic contraction that destabilized the Spk, causing its disappearance. After a short transition period, new Spk appeared where the two incipient apical branches emerged. Changes in cell shape, growth rate, and Spk position were recorded and transferred to the fungus simulator program to test the hypothesis that the Spk functions as a vesicle supply center (VSC). The simulation faithfully duplicated the elongation of the main hypha and the two apical branches. Elongating hyphae exhibited the growth pattern described by the hyphoid equation. During the transition phase, when no Spk was visible, the growth pattern was nonhyphoid, with consecutive periods of isometric and asymmetric expansion; the apex became enlarged and blunt before the apical branches emerged. Video microscopy images suggested that the branch Spk were formed anew by gradual condensation of vesicle clouds. Simulation exercises where the VSC was split into two new VSCs failed to produce realistic shapes, thus supporting the notion that the branch Spk did not originate by division of the original Spk. The best computer simulation of apical branching morphogenesis included simulations of the ontogeny of branch Spk via condensation of vesicle clouds. This study supports the hypothesis that the Spk plays a major role in hyphal morphogenesis by operating as a VSCi.e., by regulating the traffic of wall-building vesicles in the manner predicted by the hyphoid model. PMID:9256441

  1. The role of carbon starvation in the induction of enzymes that degrade plant-derived carbohydrates in Aspergillus niger.

    PubMed

    van Munster, Jolanda M; Daly, Paul; Delmas, Stphane; Pullan, Steven T; Blythe, Martin J; Malla, Sunir; Kokolski, Matthew; Noltorp, Emelie C M; Wennberg, Kristin; Fetherston, Richard; Beniston, Richard; Yu, Xiaolan; Dupree, Paul; Archer, David B

    2014-11-01

    Fungi are an important source of enzymes for saccharification of plant polysaccharides and production of biofuels. Understanding of the regulation and induction of expression of genes encoding these enzymes is still incomplete. To explore the induction mechanism, we analysed the response of the industrially important fungus Aspergillus niger to wheat straw, with a focus on events occurring shortly after exposure to the substrate. RNA sequencing showed that the transcriptional response after 6h of exposure to wheat straw was very different from the response at 24h of exposure to the same substrate. For example, less than half of the genes encoding carbohydrate active enzymes that were induced after 24h of exposure to wheat straw, were also induced after 6h exposure. Importantly, over a third of the genes induced after 6h of exposure to wheat straw were also induced during 6h of carbon starvation, indicating that carbon starvation is probably an important factor in the early response to wheat straw. The up-regulation of the expression of a high number of genes encoding CAZymes that are active on plant-derived carbohydrates during early carbon starvation suggests that these enzymes could be involved in a scouting role during starvation, releasing inducing sugars from complex plant polysaccharides. We show, using proteomics, that carbon-starved cultures indeed release CAZymes with predicted activity on plant polysaccharides. Analysis of the enzymatic activity and the reaction products, indicates that these proteins are enzymes that can degrade various plant polysaccharides to generate both known, as well as potentially new, inducers of CAZymes. PMID:24792495

  2. Tailoring fungal morphology of Aspergillus niger MYA 135 by altering the hyphal morphology and the conidia adhesion capacity: biotechnological applications

    PubMed Central

    2013-01-01

    Current problems of filamentous fungi fermentations and their further successful developments as microbial cell factories are dependent on control fungal morphology. In this connection, this work explored new experimental procedures in order to quantitatively check the potential of some culture conditions to induce a determined fungal morphology by altering both hyphal morphology and conidia adhesion capacity. The capacity of environmental conditions to modify hyphal morphology was evaluated by examining the influence of some culture conditions on the cell wall lytic potential of Aspergillus niger MYA 135. The relative value of the cell wall lytic potential was determined by measuring a cell wall lytic enzyme activity such as the mycelium-bound β-N-acetyl-D-glucosaminidase (Mb-NAGase). On the other hand, the quantitative value of conidia adhesion was considered as an index of its aggregation capacity. Concerning microscopic morphology, a highly negative correlation between the hyphal growth unit length (lHGU) and the specific Mb-NAGase activity was found (r = -0.915, P < 0.001). In fact, the environment was able to induce highly branched mycelia only under those culture conditions compatible with specific Mb-NAGase values equal to or higher than 190 U gdry.wt-1. Concerning macroscopic morphology, a low conidia adhesion capacity was followed by a dispersed mycelial growth. In fact, this study showed that conidia adhesion units per ml equal to or higher than 0.50 were necessary to afford pellets formation. In addition, it was also observed that once the pellet was formed the lHGU had an important influence on its final diameter. Finally, the biotechnological significance of such results was discussed as well. PMID:23688037

  3. Purification and Characterization of a Lipase with High Thermostability and Polar Organic Solvent-Tolerance from Aspergillus niger AN0512.

    PubMed

    Liu, Guang; Hu, Songqing; Li, Lin; Hou, Yi

    2015-11-01

    An extracellular lipase (EC 3.1.1.3, AN0512Lip) from Aspergillus niger AN0512 was purified and its characteristics were investigated. After the process of ammonium sulfate precipitation followed by ion-exchange chromatography and gel filtration, the purified lipase was achieved with 203.6-fold purification and 22.1 % recovery. AN0512Lip exhibited the highest activity at 50 °C and pH 5.0. It was thermostable and pH-stable, as indicated by that more than 50 % activity retained at 60 °C for 20 h and more than 90 % activity retained at pH 3.0 for 20 h, respectively. AN0512Lip activity was stimulated by some divalent metal ions (especially Cu(2+), Ca(2+)), while greatly suppressed by EDTA, indicating that AN0512Lip was a metal-activated enzyme. Moreover, AN0512Lip exhibited high tolerance for various polar organic solvents with log P < 0.8, and the highest lipase activity (476 % of its original activity) was achieved after addition of 90 % (V/V) isopropanol to the reaction mixture. AN0512Lip also displayed 3-regiospecificity and great affinity for the long-chain fatty ester. The preliminary test showed that AN0512Lip was a candidate for enriching EPA and DHA in fish oil. All the unique properties, such as thermostability, Cu(2+)-dependent, 3-regiospecificity, and polar organic solvent-tolerance, indicated that AN0512Lip could have potential applications in the food industry, even in organic synthesis and the pharmaceutical industry. PMID:26216145

  4. Improving the specific activity of ?-mannanase from Aspergillus niger BK01 by structure-based rational design.

    PubMed

    Huang, Jian-Wen; Chen, Chun-Chi; Huang, Chun-Hsiang; Huang, Ting-Yung; Wu, Tzu-Hui; Cheng, Ya-Shan; Ko, Tzu-Ping; Lin, Cheng-Yen; Liu, Je-Ruei; Guo, Rey-Ting

    2014-03-01

    ?-Mannanase has found various biotechnological applications because it is capable of degrading mannans into smaller sugar components. A highly potent example is the thermophilic ?-mannanase from Aspergillus niger BK01 (ManBK), which can be efficiently expressed in industrial yeast strains and is thus an attractive candidate for commercial utilizations. In order to understand the molecular mechanism, which helps in strategies to improve the enzyme's performance that would meet industrial demands, 3D-structural information is a great asset. Here, we present the 1.57 crystal structure of ManBK. The protein adopts a typical (?/?)8 fold that resembles the other GH5 family members. Polysaccharides were subsequently modeled into the substrate binding groove to identify the residues and structural features that may be involved in the catalytic reaction. Based on the structure, rational design was conducted to engineer ManBK in an attempt to enhance its enzymatic activity. Among the 23 mutants that we constructed, the most promising Y216W showed an 182.7% increase in specific activity by comparison with the wild type enzyme. The optimal temperature and heat tolerance profiles of Y216W were similar to those of the wild type, manifesting a preserved thermostability. Kinetic studies showed that Y216W has higher kcat values than the wild type enzyme, suggesting a faster turnover rate of catalysis. In this study we applied rational design to ManBK by using its crystal structure as a basis and identified the Y216W mutant that shows great potentials in industrial applications. PMID:24480109

  5. Comparsion of Cultural and Analytical Methods for Determination of Aflatoxin Production by Mississippi Delta Aspergillus isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study compared cultural versus analytical methods to detect aflatoxin production by Aspergillus species. Aspergillus isolates (517) were obtained from various Mississippi Delta crops (corn, peanut, rice, cotton) and soils. Ten standard aflatoxigenic A. flavus isolates were also included in thi...

  6. Azole resistance in canine and feline isolates of Aspergillus fumigatus.

    PubMed

    Talbot, Jessica J; Kidd, Sarah E; Martin, Patricia; Beatty, Julia A; Barrs, Vanessa R

    2015-10-01

    Azole resistance is an emerging cause of treatment failure in humans with aspergillosis. The aim of this study was to determine if azole resistance is emerging in Aspergillus fumigatus isolates from canine and feline sino-nasal aspergillosis cases. Susceptibilities of isolates collected between 1988 and 2014 from 46 dogs and 4 cats to itraconazole, posaconazole, voriconazole, fluconazole and ketoconazole were assessed using Sensititre YeastOne microdilution trays; and to enilconazole and clotrimazole, following the CLSI M38-A2 standard. For the majority of isolates MICs were high for ketoconazole, low for enilconazole and clotrimazole, and less than established epidemiological cut-off values for itraconazole, posaconazole and voriconazole. One canine isolate from 1992 had multiazole resistance and on Cyp51A gene sequencing a mutation associated with azole resistance (F46Y) was detected. There is no evidence of emerging azole resistance among A. fumigatus isolates from dogs and cats and topical azole therapy should be effective against most isolates. PMID:26387063

  7. Overexpression of the NADP+-specific isocitrate dehydrogenase gene (icdA) in citric acid-producing Aspergillus niger WU-2223L.

    PubMed

    Kobayashi, Keiichi; Hattori, Takasumi; Hayashi, Rie; Kirimura, Kohtaro

    2014-01-01

    In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form ?-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering. PMID:25229866

  8. Role of ozone in UV-C disinfection, demonstrated by comparison between wild-type and mutant conidia of Aspergillus niger.

    PubMed

    Liu, Jing; Zhou, Lin; Chen, Ji-Hong; Mao, Wang; Li, Wen-Jian; Hu, Wei; Wang, Shu-Yang; Wang, Chun-Ming

    2014-01-01

    This study aimed to investigate the tolerance of a melanized wild-type strain of Aspergillus niger (CON1) and its light-colored mutant (MUT1) to UV-C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (-UV, -O3), (-UV, +O3), (+UV, -O3) and (+UV, +O3). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical-scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV-C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau. PMID:24283963

  9. Impact of alg3 gene deletion on growth, development, pigment production, protein secretion, and functions of recombinant Trichoderma reesei cellobiohydrolases in Aspergillus niger

    SciTech Connect

    Dai, Ziyu; Aryal, Uma K.; Shukla, Anil K.; Qian, Weijun; Smith, Richard D.; Magnuson, Jon K.; Adney, William S.; Beckham, Gregg T.; Brunecky, Roman; Himmel, Michael E.; Decker, Stephen R.; Ju, Xiaohui; Zhang, Xiao; Baker, Scott E.

    2013-09-25

    ALG3 is a Family 58 glycosyltransferase enzyme involved in early N-linked glycan synthesis. Here, we investigated the effect of the alg3 gene disruption on growth, development, metabolism, and protein secretion in Aspergillus niger. The alg3 gene deletion resulted in a significant reduction of growth on complete (CM) and potato dextrose agar (PDA) media and a substantial reduction of spore production on CM. It also delayed spore germination in the liquid cultures of both CM and PDA media, but led to a significant accumulation of red pigment on both CM and liquid modified minimal medium (MM) supplemented with yeast extract. The relative abundance of 55 proteins of the total 190 proteins identified in the secretome was significantly different as a result of alg3 gene deletion. Comparison of a Trichoderma reesei cellobiohydrolase (Cel7A) heterologously expressed in A. niger parental and ∆alg3 strains showed that the recombinant Cel7A expressed in the mutant background was smaller in size than that from the parental strains. This study suggests that ALG3 is critical for growth and development, pigment production, and protein secretion in A. niger. Functional analysis of recombinant Cel7A with aberrant glycosylation demonstrates the feasibility of this alternative approach to evaluate the role of N-linked glycosylation in glycoprotein secretion and function.

  10. Malting of barley with combinations of Lactobacillus plantarum, Aspergillus niger, Trichoderma reesei, Rhizopus oligosporus and Geotrichum candidum to enhance malt quality.

    PubMed

    Hattingh, M; Alexander, A; Meijering, I; van Reenen, C A; Dicks, L M T

    2014-03-01

    Good quality malt is characterised by the presence of high levels of fermentable sugars, amino acids and vitamins. To reach the starch-rich endosperm of the kernel, ?-glucan- and arabinoxylan-rich cell walls have to be degraded. ?-Glucanase is synthesized in vast quantities by the aleurone layer and scutellum during germination. Secretion of hydrolytic enzymes is often stimulated by addition of the plant hormone gibberellic acid (GA3) during germination. We have shown an enhanced ?-glucanase and ?-amylase activity in malt when germinating barley was inoculated with a combination of Lactobacillus plantarum B.S1.6 and spores of Aspergillus niger MH1, Rhizopus oligosporus MH2 or Trichoderma reesei MH3, and L. plantarum B.S1.6 combined with cell-free culture supernatants from each of these fungi. Highest malt ?-glucanase activity (414 Units/kg malt) was recorded with a combination of L. plantarum B.S1.6 and spores of A. niger MH1. Highest ?-amylase activities were recorded with a combination of L. plantarum B.S1.6 and spores of R. oligosporus MH2 (373 Ceralpha Units/g malt). Highest FAN levels were recorded when L. plantarum was inoculated in combination with spores of either R. oligosporus MH2 or T. reesei MH3 (259 and 260 ppm, respectively). This is the first study showing that cell-free culture supernatants of Aspergillus, Rhizopus and Trichoderma have a stimulating effect on ?-glucanase and ?-amylase production during malting. A combination of L. plantarum B.S1.6, and spores of A. niger MH1 and R. oligosporus MH2 may be used as starter cultures to enhance malt quality. PMID:24412956

  11. Fumigaclavine I, a new alkaloid isolated from endophyte Aspergillus terreus.

    PubMed

    Shen, Li; Zhu, Li; Luo, Qian; Li, Xiao-Wen; Xi, Ju-Qun; Kong, Gui-Mei; Song, Yong-Chun

    2015-12-01

    The present study was designed to isolate and purify chemical constituents from solid culture of endophyte Aspergillus terreus LQ, using silica gel column chromatography, gel filtration with Sephadex LH-20, and HPLC. Fumigaclavine I (1), a new alkaloid, was obtained, along with seven known compounds, including fumigaclavine C (2), rhizoctonic acid (3), monomethylsulochrin (4), chaetominine (5), spirotryprostatin A (6), asperfumoid (7), and lumichrome (8). The structure of compound 1 was elucidated by various spectroscopic analyses (UV, MS, 1D and 2D NMR). The in vitro cytotoxicity of compound 1 was determined by MTT assay in human hepatocarcinoma cell line SMMC-7721, showing weaker cytotoxicity, compared with cisplatin, a clinically used cancer chemotherapeutic agent. PMID:26721713

  12. Physical and kinetic properties of the family 3 beta-glucosidase from Aspergillus niger which is important for cellulose breakdown.

    PubMed

    Seidle, Heather F; Marten, Ira; Shoseyov, Oded; Huber, Reuben E

    2004-01-01

    A beta-glucosidase (BGS) purified from Aspergillus niger cellulase powder (obtained from Sigma, St. Louis, MO, USA) was characterized. Electrophoresis, size exclusion chromatography, and dynamic light scattering indicated that the enzyme is a dimer of approximately 200 kDa. Five of the seven N-glycosylated oligosaccharides attached to BGS were composed of D-mannoses attached to a beta(1-4)-N-acetyl-glucosamine-beta-(1-4)-fucose-alpha-(1-6)-N-acetylglucosamine core. The other two were similar, but the cores of these did not have the D-fucose. The enzyme is a retaining glycosidase, and it also has a distinct preference for the beta-configuration at the reducing end of cellobiose. BGS is thermostable up to 65 degrees C but is sensitive to freezing and thawing. The extinction coefficient of BGS was found to be 1.8 cm(-1) mg(-1). All substrates assayed resulted in Eadie-Hofstee plots that were curved at high substrate concentrations. TLC of the reaction products showed that the substrates themselves act as acceptors when present at high concentrations. The transglucosidic activity rate is different from the hydrolytic activity rate and this causes the curvature at high substrate concentrations. The enzyme produces gentiobiose when D-glucose is the acceptor. pH optima of the Vmax(h) with pNPGlc, oNPGlc, and cellobiose were between pH 4 and 4.5, and the Km values decreased at pH values between 3 and 5. Inhibition experiments indicated that the enzyme is specific for glucosyl substrates and suggested that D-gluconolactone is a transition state analog. Studies with cello-oligosaccharides and 3,4-dinitrophenyl-cellobiose showed that BGS is an exo-hydrolase having at least five glucose subsites and that it cleaves from the nonreducing end. The properties of a family 3 beta-glucosidase (BG3) sequenced by Dan et al. [Dan, S., Marton, I., Dekel, M., Bravdo, B-A., He, S., Withers, S. G., and Shoseyov, O. (2000) J. Biol. Chem. 275: 4973-4980] was also studied and was shown to have very similar properties to those of BGS. Sequence analysis of a portion of BGS verified that these are the same enzymes. PMID:15115178

  13. Heterogeneity in liquid shaken cultures of Aspergillus niger inoculated with melanised conidia or conidia of pigmentation mutants

    PubMed Central

    van Veluw, G.J.; Teertstra, W.R.; de Bekker, C.; Vinck, A.; van Beek, N.; Muller, W.H.; Arentshorst, M.; van der Mei, H.C.; Ram, A.F.J.; Dijksterhuis, J.; Wsten, H.A.B.

    2013-01-01

    Black pigmented conidia of Aspergillus niger give rise to micro-colonies when incubated in liquid shaken medium. These micro-colonies are heterogeneous with respect to gene expression and size. We here studied the biophysical properties of the conidia of a control strain and of strains in which the fwnA, olvA or brnA gene is inactivated. These strains form fawn-, olive-, and brown-coloured conidia, respectively. The ?olvA strain produced larger conidia (3.8 ?m) when compared to the other strains (3.23.3 ?m). Moreover, the conidia of the ?olvA strain were highly hydrophilic, whereas those of the other strains were hydrophobic. The zeta potential of the ?olvA conidia in medium was also more negative when compared to the control strain. This was accompanied by the near absence of a rodlet layer of hydrophobins. Using the Complex Object Parametric Analyzer and Sorter it was shown that the ratio of individual hyphae and micro-colonies in liquid shaken cultures of the deletion strains was lower when compared to the control strain. The average size of the micro-colonies of the control strain was also smaller (628 ?m) than that of the deletion strains (790858 ?m). The size distribution of the micro-colonies of the ?fwnA strain was normally distributed, while that of the other strains could be explained by assuming a population of small and a population of large micro-colonies. In the last set of experiments it was shown that relative expression levels of gpdA, and AmyR and XlnR regulated genes correlate in individual hyphae at the periphery of micro-colonies. This indicates the existence of transcriptionally and translationally highly active and lowly active hyphae as was previously shown in macro-colonies. However, the existence of distinct populations of hyphae with high and low transcriptional and translational activity seems to be less robust when compared to macro-colonies grown on solid medium. PMID:23449476

  14. The oxygen isotope composition of phosphate released from phytic acid by the activity of wheat and Aspergillus niger phytase

    NASA Astrophysics Data System (ADS)

    Sperber, C. v.; Tamburini, F.; Brunner, B.; Bernasconi, S. M.; Frossard, E.

    2015-03-01

    Phosphorus (P) is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi) from organic phosphorus compounds (Porg). Phytic acid (IP6) is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields plant available inorganic phosphate (Pi) and less phosphorylated inositol derivates as products. The hydrolysis of organic P-compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O) of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'monophosphate (AMP) and glycerophosphate (GPO4) as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as substrate were prepared. During the hydrolysis of IP6 by phytase, four Pi are released, and one oxygen atom from water is incorporated into each Pi. This incorporation of oxygen from water into Pi is subject to an apparent inverse isotopic fractionation (ϵ ∼ 6 to 10‰), which is similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ∼ 7‰) where less than three Pi are released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ∼ -12‰), again similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ɛ to the same amino acid sequence motif (RHGXRXP) at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking substrate-dependency of the isotopic fractionation could be attributed to a difference in the δ18O-values of the C-O-P bridging and non-bridging oxygen atoms in organic phosphate compounds.

  15. The oxygen isotope composition of phosphate released from phytic acid by the activity of wheat and Aspergillus niger phytase

    NASA Astrophysics Data System (ADS)

    von Sperber, C.; Tamburini, F.; Brunner, B.; Bernasconi, S. M.; Frossard, E.

    2015-07-01

    Phosphorus (P) is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi) from organic phosphorus compounds (Porg). Phytic acid (myo-inositol hexakisphosphate, IP6) is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields available Pi and less phosphorylated inositol derivates as products. The hydrolysis of organic P compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O) of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'-monophosphate (AMP) and glycerophosphate (GPO4) as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as a substrate were prepared. During the hydrolysis of IP6 by phytase, four of the six Pi were released, and one oxygen atom from water was incorporated into each Pi. This incorporation of oxygen from water into Pi was subject to an apparent inverse isotopic fractionation (ϵ ~ 6 to 10 ‰), which was similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ~ 7 ‰), where less than three Pi were released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ~ -12 ‰), similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ϵ to the same amino acid sequence motif (RHGXRXP) at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking substrate dependency of the isotopic fractionation could be attributed to a difference in the δ18O values of the C-O-P bridging and non-bridging oxygen atoms in organic phosphate compounds.

  16. Heavy-metal-induced Inhibition of Aspergillus niger nitrate reductase: Applications for Rapid Contaminant Detection in Aqueous Samples

    SciTech Connect

    Apel, William Arnold; Aiken, Abigail Marie; Peyton, Brent Michael; Petersen, James N.

    2003-03-01

    Enzyme inhibition assays have the potential to rapidly screen and identify heavy metals in environmental samples. Inhibition of nitrate reductase (NR) was examined as a method for detecting toxic metals. The activity of NR (EC 1.6.6.2) from Aspergillus niger was assayed as a function of metal concentration in the presence of Cd2+, Cr3+, Cr6+, Cu2+, Ni2+, Pb2+, and Zn2+. NR exhibited sensitivity to these metals at concentrations below 10 µM. Various buffers were screened for their ability to protect NR activity from metal inhibition, and 3-(N-morpholino) propanesulfonic acid (MOPS) was selected as the buffering system for the NR assays as it exhibited the least interference with metal inhibition, thus providing increased assay sensitivity. The hypothesis that chelating agents could prevent the inhibition of NR activity by metal ions was also tested. Results indicated that 10 mM ethylenediaminetetraacetic acid (EDTA) could protect NR activity from inhibition by Cr3+, Cu2+, Cd2+, Ni2+, and Zn2+ at concentrations below 100 µM, but that the EDTA had no effect on NR inhibition by Cr6+. An amount of 10 mM nitrilotriacetic acid (NTA) prevented NR inhibition by Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+ at metal concentrations below 100 µM. However, 10 mM NTA was unable to protect the enzyme from inhibition by either Cr3+ or Cr6+. These results indicated that through specific metal chelation, a NR-based method for individually quantifying Cr3+ and Cr6+ species in aqueous solutions could be developed. The ability to restore activity to NR which been previously inhibited by exposure to 100 µM Pb2+, Cd2+, Zn2+, Cu2+, and Cr3+ was explored to determine whether NR activity could be recovered by EDTA additions for use in consecutive metal inhibition assays. The results showed NR activity could not be regained after exposure to Cr3+ or Cu2+, but did partially recover activity after Cd2+, Pb2+, and Zn2+ exposure.

  17. The interaction of induction and repression mechanisms in the regulation of galacturonic acid-induced genes in Aspergillus niger.

    PubMed

    Niu, Jing; Homan, Tim G; Arentshorst, Mark; de Vries, Ronald P; Visser, Jaap; Ram, Arthur F J

    2015-09-01

    Aspergillus niger is an important industrial fungus expressing a broad spectrum of pectinolytic genes. The main constituent of pectin, polygalacturonic acid (PGA), is degraded into galacturonic acid (GA) by the combined activity of endo- and exo-polygalacturonases some of which are specifically induced by GA. The regulatory mechanisms that control the expression of genes encoding PGA-degrading enzymes are not well understood. Based on available genome-wide expression profiles from literature, we selected five genes that were specifically induced by GA. These genes include three exo-polygalacturonases (pgaX, pgxB and pgxC), a GA transporter (gatA), and an intracellular enzyme involved in GA metabolism (gaaB). These five genes contain a conserved motif (5'-TCCNCCAAT-3') in their promoter regions, which we named GARE (galacturonic acid-responsive element). Promoter deletion studies and site-directed mutagenesis of the conserved motif of the pgaX gene showed that the conserved element is required for GA-mediated induction. A set of promoter reporter strains was constructed by fusing the promoter region of the five above-mentioned genes to the amdS reporter gene. Expression of the amdS gene is quantitatively correlated with ability to utilise acetamide as an N-source, hence higher expression of amdS improves growth of the strain on acetamide and therefore can be used as an in vivo reporter for gene expression. Growth analysis of the reporter strains indicated that four genes (pgaX, pgxB, pgxC, and gatA) are specifically induced by GA. The in vivo promoter reporter strains were also used to monitor carbon catabolite repression control. Except for gaaB, all promoter-reporter genes analysed were repressed by glucose in a glucose concentration-dependent way. Interestingly, the strength of glucose repression was different for the tested promoters. CreA is important in mediating carbon catabolite repression as deletion of the creA gene in the reporter strains abolished carbon catabolite repression for most promoters. Interestingly, the pgxC promoter was still repressed by glucose even in the creA null background, suggesting a role for alternative repression mechanisms. Finally, we showed that low concentrations of GA are required to induce gene expression of pgaX, pgxB, and pgxC even under derepressing conditions. The results obtained are consistent with a model in which a GA-specific transcription factor is activated by GA or a GA-derivative, which binds to the conserved motif, possibly in combination with the HAP-complex, to drive GA-specific gene expression. PMID:26127014

  18. Bioprocess and biotecnology: effect of xylanase from Aspergillus niger and Aspergillus flavus on pulp biobleaching and enzyme production using agroindustrial residues as substract.

    PubMed

    de Alencar Guimaraes, Nelciele Cavalieri; Sorgatto, Michele; Peixoto-Nogueira, Simone de Carvalho; Betini, Jorge Henrique Almeida; Zanoelo, Fabiana Fonseca; Marques, Maria Rita; de Moraes Polizeli, Maria de Lourdes Teixeira; Giannesi, Giovana C

    2013-01-01

    This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50C, the xylanase of A. niger retained over 85% activity with 2h of incubation, and A. flavus had a half-life of more than 75minutes. At 55C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45minutes. The xylanase activity of A. niger and A. flavus were somehow protected in the presence of glycerol 5% when compared to the control (without additives). On the biobleaching assay it was observed that the xylanase from A. flavus was more effective in comparison to A. niger. The kappa efficiency corresponded to 36.32 and 25.93, respectively. That is important to emphasize that the cellulase activity was either analyzed and significant levels were not detected, which explain why the viscosity was not significantly modified. PMID:24010038

  19. Non-aflatoxigenic Aspergillus flavus isolates reduce aflatoxins, cyclopiazonic acid and fumonisin in corn (maize)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus flavus strains vary widely in their production of aflatoxins and cyclopiazonic acid (CPA). A total of 500 Aspergillus strains isolated from a variety of sources showed 16.4% were negative for both aflatoxin and CPA, 41.3% were positive for both mycotoxins, 13.0% were positive only fo...

  20. NON-TOXIGENIC ASPERGILLUS FLAVUS ISOLATES FOR REDUCING AFLATOXIN IN MISSISSIPPI DELTA CORN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential for two non-toxigenic isolates of Aspergillus flavus CT3 and K49 isolated from the Mississippi Delta to reduce aflatoxin contamination of corn was assessed in a field study. These two isolates exhibited comparable growth and aggressiveness as the toxigenic A. flavus isolate F3W4. The...

  1. Growth behaviour and glucoamylase production by Aspergillus niger N402 and a glucoamylase overproducing transformant in recycling culture without a nitrogen source.

    PubMed

    Schrickx, J M; Stouthamer, A H; van Verseveld, H W

    1995-04-01

    When wild-type Aspergillus niger N402 and a glucoamylase-overproducing transformant were grown in recycling culture without a nitrogen source, hyphal tip extension and glucoamylase production still occurred, but overproduction of glucoamylase by the transformant strain stopped. The mycelium retained a low metabolic activity. Light micrographs of mycelial samples showed that some hyphae were broken at their tip and partially empty, while after continuing recycling fermentation for more than 500 h many small and empty pieces of broken mycelium could be found. A model has been developed to calculate the mycelial growth and death rates. The mycelial death rate just exceeded the mycelial growth rate and as a consequence the amount of biomass in the fermentor vessel slightly decreased. It is concluded that the cytoplasmic contents of broken mycelial threads were released into the medium and acted as a nitrogen source for the growing parts of the mycelium. PMID:7766124

  2. Discovery and Characterization of a Silent Gene Cluster that Produces Azaphilones from Aspergillus niger ATCC 1015 Reveal a Hydroxylation-Mediated Pyran-Ring Formation

    PubMed Central

    Zabala, Angelica O.; Xu, Wei; Chooi, Yit-Heng; Tang, Yi

    2012-01-01

    SUMMARY Azaphilones are a class of fungal metabolites characterized by a highly oxygenated pyrano-quinone bicyclic core and exhibits a broad range of bioactivities. While widespread among various fungi, their biosynthesis has not been thoroughly elucidated. By activation of a silent (aza) gene cluster in Aspergillus niger ATCC 1015, we have discovered six new azaphilone compounds, azanigerones A-F (1, 3-7). Transcriptional analysis and deletion of a key polyketide synthase (PKS) gene further confirmed the involvement of the aza gene cluster. The biosynthetic pathway was shown to involve the convergent actions of a highly-reducing and a non-reducing PKSs. Most significantly, in vitro reaction of a key flavin-dependent monooxygenase encoded in the cluster with an early benzaldehyde intermediate revealed its roles in hydroxylation and pyran-ring formation to afford the characteristic bicylic core shared by azaphilones. PMID:22921072

  3. Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil

    PubMed Central

    Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

    2013-01-01

    In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source. PMID:24086254

  4. Role of different additives and metallic micro minerals on the enhanced citric acid production by Aspergillus niger MNNG-115 using different carbohydrate materials.

    PubMed

    Ali, Sikander; Haq, Ikram-ul

    2005-01-01

    The present investigation deals with the promotry effect of different additives and metallic micro minerals on citric acid production by Aspergillus niger MNNG-115 using different carbohydrate materials. For this, sugar cane bagasse was fortified with sucrose salt medium. Ethanol and coconut oil at 3.0% (v/w) level increased citric acid productivity. Fluoroacetate at a concentration of 1.0 mg/ml bagasse enhanced the yield of citric acid significantly. However, the addition of ethanol and fluoroacetate after 6 h of growth gave the maximum conversion of available sugar to citric acid. In another study, influence of some metallic micro-minerals viz. copper sulphate, molybdenum sulphate, zinc sulphate and cobalt sulphate on microbial synthesis of citric acid using molasses medium was also carried out. It was found that copper sulphate and molybdenum sulphate remarkably enhanced the production of citric acid while zinc sulphate was not so effective. However, cobalt sulphate was the least effective for microbial biosynthesis of citric acid under the same experimental conditions. In case of CuSO(4), the strain of Aspergillus niger MNNG-115 showed enhanced citric productivity with experimental (9.80%) over the control (7.54%). In addition, the specific productivity of the culture at 30 ppm CuSO(4) (Q(p) = 0.012a g/g cells/h) was several folds higher than other all other concentrations. All kinetic parameters including yield coefficients and volumetric rates revealed the hyper productivity of citric acid by CuSO(4) using blackstrap molasses as the basal carbon source. PMID:15678560

  5. Replacement of two amino acids of 9R-dioxygenase-allene oxide synthase of Aspergillus niger inverts the chirality of the hydroperoxide and the allene oxide.

    PubMed

    Sooman, Linda; Wennman, Anneli; Hamberg, Mats; Hoffmann, Inga; Oliw, Ernst H

    2016-02-01

    The genome of Aspergillus niger codes for a fusion protein (EHA25900), which can be aligned with ~50% sequence identity to 9S-dioxygenase (DOX)-allene oxide synthase (AOS) of Fusarium oxysporum, homologues of the Fusarium and Colletotrichum complexes and with over 62% sequence identity to homologues of Aspergilli, including (DOX)-9R-AOS of Aspergillus terreus. The aims were to characterize the enzymatic activities of EHA25900 and to identify crucial amino acids for the stereospecificity. Recombinant EHA25900 oxidized 18:2n-6 sequentially to 9R-hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HPODE) and to a 9R(10)-allene oxide. 9S- and 9R-DOX-AOS catalyze abstraction of the pro-R hydrogen at C-11, but the direction of oxygen insertion differs. A comparison between twelve 9-DOX domains of 9S- and 9R-DOX-AOS revealed conserved amino acid differences, which could contribute to the chirality of products. The Gly616Ile replacement of 9R-DOX-AOS (A. niger) increased the biosynthesis of 9S-HPODE and the 9S(10)-allene oxide, whereas the Phe627Leu replacement led to biosynthesis of 9S-HPODE and the 9S(10)-allene oxide as main products. The double mutant (Gly616Ile, Phe627Leu) formed over 90% of the 9S stereoisomer of HPODE. 9S-HPODE was formed by antarafacial hydrogen abstraction and oxygen insertion, i.e., the original H-abstraction was retained but the product chirality was altered. We conclude that 9R-DOX-AOS can be altered to 9S-DOX-AOS by replacement of two amino acids (Gly616Ile, Phe627Leu) in the DOX domain. PMID:26603902

  6. Ribotoxin genes in isolates of Aspergillus section Clavati

    PubMed Central

    Samson, Robert A.

    2008-01-01

    Ribotoxins are ribosome inactivator proteins with high specificity against the sarcin/ricin domain of the 28S ribosomal RNA. We examined the presence of ribotoxin genes in isolates of species recently assigned to Aspergillus section Clavati using specific primer pairs. All species assigned to this section have been found to carry ribotoxin genes. Phylogenetic analysis of the sequences of the amplified gene fragments allowed us to classify the genes to different groups including the ?-sarcin, gigantin, c-sarcin and mitogillin/restrictocin families. Two species, A. longivesica and N. acanthosporus produced ribotoxins which were only distantly related to gigantins and c-sarcins, respectively. Comparison of the protein sequences of the genes to known ribotoxin sequences revealed that all of them carry the presumed catalytic residues of ribotoxins, the cystein residues, and also the two Trp residues of ?-sarcin conserved in all ribotoxins known so far. These data indicate that these genes probably encode active ribotoxins. Further studies are in progress to examine the secretion and activities of these new ribotoxins. PMID:18600469

  7. Expression and biochemical characterization of recombinant α-l-rhamnosidase r-Rha1 from Aspergillus niger JMU-TS528.

    PubMed

    Li, Lijun; Yu, Yue; Zhang, Xia; Jiang, Zedong; Zhu, Yanbing; Xiao, Anfeng; Ni, Hui; Chen, Feng

    2016-04-01

    A putative cDNA of α-l-rhamnosidase was PCR-cloned from Aspergillus niger JMU-TS528 and further extracellular over-expressed in Pichia pastoris GS115. The activity of the recombinant α-l-rhamnosidase r-Rha1 was 711.9U/mL, eightfold higher than the native α-l-rhamnosidase from A. niger JMU-TS528. r-Rha1 is a N-glycosylated protein of 90kDa and possesses broad substrate specificities by hydrolyzing α-1,2, α-1,3 α-1,4, and α-1,6 linkages to β-d-glucosides. This is the first report presenting that α-l-rhamnosidase showed activity on four kinds of glucosidic linkages. Compared with other previously characterized α-l-rhamnosidases, r-Rha1 showed a good thermostability and wide range of pH-stability with the optimum pH of 5.0 and temperature of 60°C. r-Rha1 activity was not greatly affected by representative metal ions and other detected effectors and showed excellent tolerance abilities against glucose and ethanol. These beneficial characteristics of r-Rha1 suggest that r-Rha1 should be considered a potential new biocatalyst for food and drug industrial applications. PMID:26769090

  8. Study of the rice straw biodegradation in mixed culture of Trichoderma viride and Aspergillus niger by GC-MS and FTIR.

    PubMed

    Chen, Yaoning; Huang, Jingxia; Li, Yuanping; Zeng, Guangming; Zhang, Jiachao; Huang, Aizhi; Zhang, Jie; Ma, Shuang; Tan, Xuebin; Xu, Wei; Zhou, Wei

    2015-07-01

    This study was conducted to investigate the biodegradation ability of the mixed culture of Trichoderma viride and Aspergillus niger through the study of the organic matter extracted from rice straw and the lignocellulose structure by using gas chromatography-mass spectrometer (GC-MS) and Fourier transform infrared spectroscopy (FTIR). The results of the GC-MS showed that the mixed culture possessed shorter alkane (heptane) at the end of the incubation and more kinds of organic matter (except the alkanes, 29 kinds of organic matter were detected) than the pure cultures. It could be deduced that the organic matter could indicate the degradation degree of the lignocellulose to some extent. Moreover, pinene was detected in the mixed culture on days 5 and 10, which might represent the antagonistic relationship between T. viride and A. niger. The analysis of FTIR spectrums which indirectly verified the GC-MS results showed that the mixed culture possessed a better degradation of rice straw compared with the pure culture. Therefore, the methods used in this research could be considered as effective ones to investigate the lignocellulose degradation mechanism in mixed culture. PMID:25639249

  9. Effects of fungal (Aspergillus niger or Ceriporiopsis subvermispora) fermentation on the nutritive value of shea nut (Vitellaria paradoxa) meal for broiler chicks.

    PubMed

    Dei, H K; Rose, S P; Mackenzie, A M

    2008-05-01

    1. Shea nut (Vitellaria paradoxa Gaertn.) meal was fermented for 8 d with either Aspergillus niger, Ceriporiopsis subvermispora or a mixture of the two organisms. The fermentation was completed using two methods, an opened container or a closed container. 2. Each of the 6 samples was dried and incorporated into basal broiler diets at 90 g/kg. 3. In addition, the unfermented shea nut meal was incorporated in the diet at 90 g/kg and the basal diet (maize and soybean meal based) was also provided as an eighth dietary treatment to individually caged broiler chickens. 4. All fermented fungi-treated shea nut meals had similar proximate nutrient compositions to the unfermented shea nut meal, but there were substantial decreases in their hydrolysable tannins and saponin contents. Both fermentation methods gave similar reductions in the concentrations of tannins and saponins. 5. Shea nut meal fermented with individual or both fungal organisms gave greater (P < 0.001) growth performance than that of unfermented shea nut meal. However, all shea nut meals including the unfermented meal gave lower (P < 0.001) growth variables than those for the maize-soybean meal control. 6. The nutritional improvement of shea nut meal achieved in this study still falls far short of what is expected for it to become valuable for the poultry feed industry. These fermentation methods using A. niger or C. subvermispora require further improvements to provide satisfactory feed products. PMID:18568761

  10. Relationships between aflatoxin production, sclerotia formation among isolates of Aspergillus section Flavi from the Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aspergillus isolates from different crops and from soils of the Mississippi Delta differed significantly in production of aflatoxin and sclerotia. Overall about 50% of the isolates from corn, soil, and peanut produced large sclerotia, while only 20% of the rice isolates produced large sclerotia. T...

  11. In vitro activity of two echinocandin derivatives, LY303366 and MK-0991 (L-743,792), against clinical isolates of Aspergillus, Fusarium, Rhizopus, and other filamentous fungi.

    PubMed

    Pfaller, M A; Marco, F; Messer, S A; Jones, R N

    1998-04-01

    LY303366 and MK-0991 (previously L-743,792) are new echinocandin derivatives with excellent broad-spectrum antifungal activity. We investigated the in vitro activity of LY303366, MK-0991, itraconazole, amnphotericin B, and 5-flucytosine against 51 clinical isolates of filamentous fungi, including Aspergillus flavus (10), A. fumigatus (12), Fusarium spp. (13), Rhizopus spp. (6), Pseudallescheria boydii (5), and one isolate each of Acremonium spp., A. niger, A terreus, Paecilomyces spp., and Trichoderma spp. In vitro susceptibility testing was performed using a microdilution broth method performed according to National Committee for Clinical Laboratory Standards guidelines. Ly303366 was two- to fourfold more active than MK-0991 against A. flavus, A. fumigatus, and Trichoderma spp. Both LY303366 and MK-0991 were considerably more active (MIC90 of 0.03-0.12 micrograms/mL) than itraconazole, amphotericin B, and 5-flucytosine against Aspergillus spp., but were less active than intraconazole and amphotericin B against Rhizopus spp. MK-0991 was more active than either LY303366 or intraconazole against Acremonium spp., Paecilomyces spp., and P. boydii. These data demonstrate promising activity of both LY303366 and MK-0991 against Aspergillus spp. and other species of filamentous fungi that are likely to be encountered clinically. Further in vitro and in vivo investigation is indicated. PMID:9582584

  12. LAMP-PCR detection of ochratoxigenic Aspergillus species collected from peanut kernel.

    PubMed

    Al-Sheikh, H M

    2015-01-01

    Over the last decade, ochratoxin A (OTA) has been widely described and is ubiquitous in several agricultural products. Ochratoxins represent the second-most important mycotoxin group after aflatoxins. A total of 34 samples were surveyed from 3 locations, including Mecca, Madina, and Riyadh, Saudi Arabia, during 2012. Fungal contamination frequency was determined for surface-sterilized peanut seeds, which were seeded onto malt extract agar media. Aspergillus niger (35%), Aspergillus ochraceus (30%), and Aspergillus carbonarius (25%) were the most frequently observed Aspergillius species, while Aspergillus flavus and Aspergillus phoenicis isolates were only infrequently recovered and in small numbers (10%). OTA production was evaluated on yeast extract sucrose medium, which revealed that 57% of the isolates were A. niger and 60% of A. carbonarius isolates were OTA producers; 100% belonged to A. ochraceus. Only one isolate, morphologically identified as A. carbonarius, and 3 A. niger isolates unstably produced OTA. A polymerase chain reaction (PCR)-based identification and detection assay was used to identify A. ochraceus isolates. Using the primer sets OCRA1/OCRA2, 400-base pair PCR fragments were produced only when genomic DNA from A. ochraceus isolates was used. Recently, the loop-mediated isothermal amplification assay using recombinase polymerase amplification chemistry was used for A. carbonarius and A. niger DNA identification. As a non-gel-based technique, the amplification product was directly visualized in the reaction tube after adding calcein for naked-eye examination. PMID:25729999

  13. Multiplex PCR analysis of fumonisin biosynthetic genes in fumonisin-nonproducing Aspergillus niger and A. awamori strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to determine the genetic basis for loss of fumonisin B¬2 (FB2) biosynthesis in FB2 non-producing A. niger strains, we developed multiplex PCR primer sets to amplify fragments of eight fumonisin biosynthetic pathway (fum) genes. Fragments of all eight fum genes were amplified in FB2-produci...

  14. Morphological and molecular identification of filamentous Aspergillus flavus and Aspergillus parasiticus isolated from compound feeds in South Africa.

    PubMed

    Iheanacho, Henry E; Njobeh, Patrick B; Dutton, Francis M; Steenkamp, Paul A; Steenkamp, Lucia; Mthombeni, Julian Q; Daru, Barnabas H; Makun, Anthony H

    2014-12-01

    Isolation of filamentous species of two Aspergillum genera from compound feeds produced in South Africa, and subsequent extraction of their individual DNA in this study, presents a simple but rapid molecular procedure for high through-put analysis of the individual morphological forms. DNA was successfully isolated from the Aspergillus spp. from agar cultures by use of a commercial kit. Agarose gel electrophoresis fractionation of the fungi DNA, showed distinct bands. The DNA extracted by this procedure appears to be relatively pure with a ratio absorbance at 260 and 280nm. However, the overall morphological and molecular data indicated that 67.5 and 51.1% of feed samples were found to be contaminated with Aspergillus flavus and Aspergillus parasiticus, respectively, with poultry feed having the highest contamination mean level of 5.7נ105CFU/g when compared to cattle (mean: 4.0נ106CFU/g), pig (mean: 2.7נ104CFU/g) and horse (1.0נ102CFU) feed. This technique presents a readily achievable, easy to use method in the extraction of filamentous fungal DNA and it's identification. Hence serves as an important tool towards molecular study of these organisms for routine analysis check in monitoring and improving compound feed quality against fungal contamination. PMID:25084661

  15. Atypical Aspergillus parasiticus isolates from pistachio with aflR gene nucleotide insertion identical to Aspergillus sojae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aflatoxins are the most toxic and carcinogenic secondary metabolites produced primarily by the filamentous fungi Aspergillus flavus and Aspergillus parasiticus. The toxins cause devastating economic losses because of strict regulations on distribution of contaminated products. Aspergillus sojae are...

  16. Isolation of maize soil and rhizosphere bacteria with antagonistic activity against Aspergillus flavus and Fusarium verticillioides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial isolates from Mississippi maize field soil and maize rhizosphere samples were evaluated for their potential as biological control agents against Aspergillus flavus and Fusarium verticillioides. Isolated strains were screened for antagonistic activities in liquid co-culture against A. flav...

  17. ENZYMATIC DEHAIRING OF CATTLE HIDE WITH AN ALKALINE PROTEASE ISOLATED FROM ASPERGILLUS TAMARII

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An alkaline protease isolated from Aspergillus tamarii shows promise as a dehairing agent for use in the tannery. Standard dehairing conditions established for the protease isolated from Streptomyces griseus proved to be unsatisfactory for the alkaline protease. We optimized the dehairing conditio...

  18. Aflaquinolones A-G: Secondary metabolites from marine and fungicolous isolates of Aspergillus spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven new compounds (aflaquinolones A-G; 1-7) containing dihydroquinolin-2-one and terpenoid units have been isolated from two different fungal sources. Two of these metabolites (1 and 2) were obtained from a Hawaiian fungicolous isolate of Aspergillus sp. (section Flavipedes; MYC-2048=NRRL 58570), ...

  19. Aspergillus species: An emerging pathogen in onychomycosis among diabetics

    PubMed Central

    Wijesuriya, T. M.; Kottahachchi, J.; Gunasekara, T. D. C. P.; Bulugahapitiya, U.; Ranasinghe, K. N. P.; Neluka Fernando, S. S.; Weerasekara, M. M.

    2015-01-01

    Introduction: Approximately, 33% patients with diabetes are afflicted with onychomycosis. In the past, nondermatophyte molds have been regarded as opportunistic pathogens; recently, Aspergillus species are considered as emerging pathogens of toenail infections. In Sri Lanka, the prevalence of Aspergillus species in onychomycosis among diabetics is not well documented. Objective: To determine the proportion of Aspergillus onychomycosis, risk factors and knowledge among diabetics. Materials and Methods: This was descriptive cross-sectional study. Three hundred diabetic patients were included. Clinical examinations of patients toenails were performed by a clinical microbiologist. Laboratory identification was done, and pathogens were identified to the species level by morpho-physiological methods. All inferential statistics were tested at P < 0.05. Results: Among clinically suspected patients, 85% (255/300) were mycologically confirmed to have onychomycosis. Aspergillus species were most commonly isolated n = 180 (71%) followed by dermatophytes, yeasts, and other molds n = 75 (29%). Of the patients having Aspergillus onychomycosis, 149 (83%) were in the > age group. In men, Aspergillus onycomycosis was seen in 82%. Among patients who had Aspergillus nail infection, 114 (63%) had diabetes for a period of > years. Among patients who were engaged in agricultural activities, 77% were confirmed to have infected nails due to Aspergillus species. Conclusion: Aspergillus niger was the most common pathogen isolated from toenail infection. Aspergillus species should be considered as an important pathogen in toenail onychomycosis in diabetic patients. Risk factors associated with Aspergillus onychomycosis were age, gender, duration of diabetes, length of exposure to fungi, and occupation. PMID:26693433

  20. Time-Kill Kinetics and In Vitro Antifungal Susceptibility of Non-fumigatus Aspergillus Species Isolated from Patients with Ocular Mycoses.

    PubMed

    Öz, Yasemin; Özdemir, Havva Gül; Gökbolat, Egemen; Kiraz, Nuri; Ilkit, Macit; Seyedmousavi, Seyedmojtaba

    2016-04-01

    Aspergillus species can cause ocular morbidity and blindness, and thus, appropriate antifungal therapy is needed. We investigated the in vitro activity of itraconazole, voriconazole, posaconazole, caspofungin, anidulafungin, and amphotericin B against 14 Aspergillus isolates obtained from patients with ocular mycoses, using the CLSI reference broth microdilution methodology. In addition, time-kill assays were performed, exposing each isolate separately to 1-, 4-, and 16-fold concentrations above the minimum inhibitory concentration (MIC) of each antifungal agent. A sigmoid maximum-effect (E max) model was used to fit the time-kill curve data. The drug effect was further evaluated by measuring an increase/decrease in the killing rate of the tested isolates. The MICs of amphotericin B, itraconazole, voriconazole, and posaconazole were 0.5-1.0, 1.0, 0.5-1.0, and 0.25 µg/ml for A. brasiliensis, A. niger, and A. tubingensis isolates, respectively, and 2.0-4.0, 0.5, 1.0 for A. flavus, and 0.12-0.25 µg/ml for A. nomius isolates, respectively. A. calidoustus had the highest MIC range for the azoles (4.0-16.0 µg/ml) among all isolates tested. The minimum effective concentrations of caspofungin and anidulafungin were ≤0.03-0.5 µg/ml and ≤0.03 µg/ml for all isolates, respectively. Posaconazole demonstrated maximal killing rates (E max = 0.63 h(-1), r (2) = 0.71) against 14 ocular Aspergillus isolates, followed by amphotericin B (E max = 0.39 h(-1), r (2) = 0.87), voriconazole (E max = 0.35 h(-1), r (2) = 0.098), and itraconazole (E max = 0.01 h(-1), r (2) = 0.98). Overall, the antifungal susceptibility of the non-fumigatus Aspergillus isolates tested was species and antifungal agent dependent. Analysis of the kinetic growth assays, along with consideration of the killing rates, revealed that posaconazole was the most effective antifungal against all of the isolates. PMID:26612621

  1. High level phytase production by Aspergillus niger NCIM 563 in solid state culture: response surface optimization, up-scaling, and its partial characterization.

    PubMed

    Bhavsar, K; Kumar, V Ravi; Khire, J M

    2011-09-01

    Phytase production by Aspergillus niger NCIM 563 was optimized by using wheat bran in solid state fermentation (SSF). An integrated statistical optimization approach involving the combination of Placket-Burman design (PBD) and Box-Behnken design (BBD) was employed. PBD was used to evaluate the effect of 11 variables related to phytase production, and five statistically significant variables, namely, glucose, dextrin, NaNO(3), distilled water, and MgSO(4) 7H(2)O, were selected for further optimization studies. The levels of five variables for maximum phytase production were determined by a BBD. Phytase production improved from 50 IU/g dry moldy bran (DMB) to 154 IU/g DMB indicating 3.08-fold increase after optimization. A simultaneous reduction in fermentation time from 7 to 4 days shows a high productivity of 38,500 IU/kg/day. Scaling up the process in trays gave reproducible phytase production overcoming industrial constraints of practicability and economics. The culture extract also had 133.2, 41.58, and 310.34 IU/g DMB of xylanase, cellulase, and amylase activities, respectively. The partially purified phytase was optimally active at 55C and pH 6.0. The enzyme retained ca. 75% activity over a wide pH range 2.0-9.5. It also released more inorganic phosphorus from soybean meal in a broad pH range from 2.5 to 6.5 under emulated gastric conditions. Molecular weight of phytase on Sephacryl S-200 was approximately 87 kDa. The K (m) and V (max) observed were 0.156 mM and 220 ?m/min/mg. The SSF phytase from A. niger NCIM 563 offers an economical production capability and its wide pH stability shows its suitability for use in poultry feed. PMID:21184251

  2. Biodiversity and ITS-RFLP Characterisation of Aspergillus Section Nigri Isolates in Grapes from Four Traditional Grape-Producing Areas in Greece

    PubMed Central

    Kizis, Dimosthenis; Natskoulis, Pantelis; Nychas, George-John E.; Panagou, Efstathios Z.

    2014-01-01

    A study on the occurrence of Aspergillus section Nigri species on grapes from four traditional grape-producing areas in Greece during the 2011/2012 vintage, and their capability to produce OTA was conducted. One hundred and twenty-eight black aspergilli isolates were characterised at the species level initially by the use of morphological criteria in accordance with appropriate keys, followed by molecular characterisation performed with Polymerase Chain ReactionRestriction Fragment Length Polymorphism (PCR-RFLP) of the 5.8 ribosomal RNA gene Internal Transcribed Spacer region (5.8 rRNA ITS). Restriction enzyme digestion of the ITS amplicons using the HhaI, HinfI and RsaI, endonucleases distinguished eleven different patterns of restriction fragment length polymorphism (RFLP), four for each of the HhaI and RsaI digests and three for HinfI. From a total number of 128 individual isolates, 124 were classified into four Aspergillus species corresponding to A. carbonarius, A. tubingensis, A. japonicus and A. ibericus, and the remaining 4 were classified as members of the A. niger aggregate. A. carbonarius and A. tubingensis being the main representative species were equally counted, with higher geographical representation of the former in southern and the latter in northern regions, respectively. All isolates were tested for their ochratoxigenic potential by use of High Performance Liquid Chromatography (HPLC) and Enzyme Linked Immuno Sorbent Assay (ELISA), resulting in significant interspecies differences in OTA production. PMID:24710283

  3. Isolation and characterization of polygalacturonase genes (pecA and pecB) from Aspergillus flavus.

    PubMed Central

    Whitehead, M P; Shieh, M T; Cleveland, T E; Cary, J W; Dean, R A

    1995-01-01

    Two genes, pecA and pecB, encoding endopolyglacturonases were cloned from a highly aggressive strain of Aspergillus flavus. The pecA gene consisted of 1,228 bp encoding a protein of 363 amino acids with a predicted molecular mass of 37.6 kDa, interrupted by two introns of 58 and 81 bp in length. Accumulation of pecA mRNA in both pectin- or glucose-grown mycelia in the highly aggressive strain matched the activity profile of a pectinase previously identified as P2c. Transformants of a weakly aggressive strain containing a functional copy of the pecA gene produced P2c in vitro, confirming that pecA encodes P2c. The coding region of pecB was determined to be 1,217 bp in length interrupted by two introns of 65 and 54 bp in length. The predicted protein of 366 amino acids had an estimated molecular mass of 38 kDa. Transcripts of this gene accumulated in mycelia grown in medium containing pectin alone, never in mycelia grown in glucose-containing medium, for both highly and weakly aggressive strains. Thus, pecB encodes the activity previously identified as P1 or P3. pecA and pecB share a high degree of sequence identity with polygalacturonase genes from Aspergillus parasiticus and Aspergillus oryzae, further establishing the close relationships between members of the A. flavus group. Conservation of intron positions in these genes also indicates that they share a common ancestor with genes encoding endopolyglacturonases of Aspergillus niger. PMID:7574642

  4. Production of an endoinulinase from Aspergillus niger AUMC 9375, by solid state fermentation of agricultural wastes, with purification and characterization of the free and immobilized enzyme.

    PubMed

    Housseiny, Manal M

    2014-05-01

    Two different substrates, sunflower (Helianthus annuus L.) tubers and lettuce (Lactuca sativa) roots, were tested. Using a mixture of both wastes resulted in higher production of endoinulinase than either waste alone. Also, ten fungal species grown on these substrates as inexpensive, carbon sources were screened for the best production of endoinulinase activities. Of these, Aspergillus niger AUMC 9375 was the most productive, when grown on the mixture using a 6:1 w/w ratio of sun flower: lettuce, and yielded the highest levels of inulinase at 50% moisture, 30C, pH 5.0, with seven days of incubation, and with yeast extract as the best nitrogen source. Inulinase was purified to homogeneity by ion-exchange chromatography and gel-filtration giving a 51.11 fold purification. The mixture of sunflower tubers and lettuce roots has potential to be an effective and economical substrate for inulinase production. Inulinase was successfully immobilized with an immobilization yield of 71.28%. After incubation for 2 h at 60C, the free enzyme activity decreased markedly to 10%, whereas that of the immobilized form decreased only to 87%. A reusability test demonstrated the durability of the immobilized inulinase for 10 cycles and in addition, that it could be stored for 32 days at 4C. These results indicate that this inulinase, in the immobilized form, is a potential candidate for large-scale production of high purity fructose syrups. PMID:24810318

  5. Effect of C/N ratio and media optimization through response surface methodology on simultaneous productions of intra- and extracellular inulinase and invertase from Aspergillus niger ATCC 20611.

    PubMed

    Dinarvand, Mojdeh; Rezaee, Malahat; Masomian, Malihe; Jazayeri, Seyed Davoud; Zareian, Mohsen; Abbasi, Sahar; Ariff, Arbakariya B

    2013-01-01

    The study is to identify the extraction of intracellular inulinase (exo- and endoinulinase) and invertase as well as optimization medium composition for maximum productions of intra- and extracellular enzymes from Aspergillus niger ATCC 20611. From two different methods for extraction of intracellular enzymes, ultrasonic method was found more effective. Response surface methodology (RSM) with a five-variable and three-level central composite design (CCD) was employed to optimize the medium composition. The effect of five main reaction parameters including sucrose, yeast extract, NaNO?, Zn?, and Triton X-100 on the production of enzymes was analyzed. A modified quadratic model was fitted to the data with a coefficient of determination (R) more than 0.90 for all responses. The intra-extracellular inulinase and invertase productions increased in the range from 16 to 8.4 times in the optimized medium (10% (w/v) sucrose, 2.5% (w/v) yeast extract, 2% (w/v) NaNO?, 1.5?mM (v/v) Zn?, and 1% (v/v) Triton X-100) by RSM and from around 1.2 to 1.3 times greater than in the medium optimized by one-factor-at-a-time, respectively. The results of bioprocesses optimization can be useful in the scale-up fermentation and food industry. PMID:24151605

  6. Effects of high pressure homogenization on the activity, stability, kinetics and three-dimensional conformation of a glucose oxidase produced by Aspergillus niger.

    PubMed

    Tribst, Alline Artigiani Lima; Cota, Jnio; Murakami, Mario Tyago; Cristianini, Marcelo

    2014-01-01

    High pressure homogenization (HPH) is a non-thermal method, which has been employed to change the activity and stability of biotechnologically relevant enzymes. This work investigated how HPH affects the structural and functional characteristics of a glucose oxidase (GO) from Aspergillus niger. The enzyme was homogenized at 75 and 150 MPa and the effects were evaluated with respect to the enzyme activity, stability, kinetic parameters and molecular structure. The enzyme showed a pH-dependent response to the HPH treatment, with reduction or maintenance of activity at pH 4.5-6.0 and a remarkable activity increase (30-300%) at pH 6.5 in all tested temperatures (15, 50 and 75C). The enzyme thermal tolerance was reduced due to HPH treatment and the storage for 24 h at high temperatures (50 and 75C) also caused a reduction of activity. Interestingly, at lower temperatures (15C) the activity levels were slightly higher than that observed for native enzyme or at least maintained. These effects of HPH treatment on function and stability of GO were further investigated by spectroscopic methods. Both fluorescence and circular dichroism revealed conformational changes in the molecular structure of the enzyme that might be associated with the distinct functional and stability behavior of GO. PMID:25061935

  7. Structure and Properties of a Non-processive, Salt-requiring, and Acidophilic Pectin Methylesterase from Aspergillus niger Provide Insights into the Key Determinants of Processivity Control.

    PubMed

    Kent, Lisa M; Loo, Trevor S; Melton, Laurence D; Mercadante, Davide; Williams, Martin A K; Jameson, Geoffrey B

    2016-01-15

    Many pectin methylesterases (PMEs) are expressed in plants to modify plant cell-wall pectins for various physiological roles. These pectins are also attacked by PMEs from phytopathogens and phytophagous insects. The de-methylesterification by PMEs of the O6-methyl ester groups of the homogalacturonan component of pectin, exposing galacturonic acids, can occur processively or non-processively, respectively, describing sequential versus single de-methylesterification events occurring before enzyme-substrate dissociation. The high resolution x-ray structures of a PME from Aspergillus niger in deglycosylated and Asn-linked N-acetylglucosamine-stub forms reveal a 10⅔-turn parallel β-helix (similar to but with less extensive loops than bacterial, plant, and insect PMEs). Capillary electrophoresis shows that this PME is non-processive, halophilic, and acidophilic. Molecular dynamics simulations and electrostatic potential calculations reveal very different behavior and properties compared with processive PMEs. Specifically, uncorrelated rotations are observed about the glycosidic bonds of a partially de-methyl-esterified decasaccharide model substrate, in sharp contrast to the correlated rotations of processive PMEs, and the substrate-binding groove is negatively not positively charged. PMID:26567911

  8. Effects of High Pressure Homogenization on the Activity, Stability, Kinetics and Three-Dimensional Conformation of a Glucose Oxidase Produced by Aspergillus niger

    PubMed Central

    Tribst, Alline Artigiani Lima; Cota, Júnio; Murakami, Mario Tyago; Cristianini, Marcelo

    2014-01-01

    High pressure homogenization (HPH) is a non-thermal method, which has been employed to change the activity and stability of biotechnologically relevant enzymes. This work investigated how HPH affects the structural and functional characteristics of a glucose oxidase (GO) from Aspergillus niger. The enzyme was homogenized at 75 and 150 MPa and the effects were evaluated with respect to the enzyme activity, stability, kinetic parameters and molecular structure. The enzyme showed a pH-dependent response to the HPH treatment, with reduction or maintenance of activity at pH 4.5–6.0 and a remarkable activity increase (30–300%) at pH 6.5 in all tested temperatures (15, 50 and 75°C). The enzyme thermal tolerance was reduced due to HPH treatment and the storage for 24 h at high temperatures (50 and 75°C) also caused a reduction of activity. Interestingly, at lower temperatures (15°C) the activity levels were slightly higher than that observed for native enzyme or at least maintained. These effects of HPH treatment on function and stability of GO were further investigated by spectroscopic methods. Both fluorescence and circular dichroism revealed conformational changes in the molecular structure of the enzyme that might be associated with the distinct functional and stability behavior of GO. PMID:25061935

  9. Effect of C/N Ratio and Media Optimization through Response Surface Methodology on Simultaneous Productions of Intra- and Extracellular Inulinase and Invertase from Aspergillus niger ATCC 20611

    PubMed Central

    Dinarvand, Mojdeh; Rezaee, Malahat; Masomian, Malihe; Jazayeri, Seyed Davoud; Zareian, Mohsen; Abbasi, Sahar; Ariff, Arbakariya B.

    2013-01-01

    The study is to identify the extraction of intracellular inulinase (exo- and endoinulinase) and invertase as well as optimization medium composition for maximum productions of intra- and extracellular enzymes from Aspergillus niger ATCC 20611. From two different methods for extraction of intracellular enzymes, ultrasonic method was found more effective. Response surface methodology (RSM) with a five-variable and three-level central composite design (CCD) was employed to optimize the medium composition. The effect of five main reaction parameters including sucrose, yeast extract, NaNO3, Zn+2, and Triton X-100 on the production of enzymes was analyzed. A modified quadratic model was fitted to the data with a coefficient of determination (R2) more than 0.90 for all responses. The intra-extracellular inulinase and invertase productions increased in the range from 16 to 8.4 times in the optimized medium (10% (w/v) sucrose, 2.5% (w/v) yeast extract, 2% (w/v) NaNO3, 1.5?mM (v/v) Zn+2, and 1% (v/v) Triton X-100) by RSM and from around 1.2 to 1.3 times greater than in the medium optimized by one-factor-at-a-time, respectively. The results of bioprocesses optimization can be useful in the scale-up fermentation and food industry. PMID:24151605

  10. Development of a Rapid Immunochromatographic Lateral Flow Device Capable of Differentiating Phytase Expressed from Recombinant Aspergillus niger phyA2 and Genetically Modified Corn.

    PubMed

    Zhou, Xiaojin; Hui, Elizabeth; Yu, Xiao-Lin; Lin, Zhen; Pu, Ling-Kui; Tu, Zhiguan; Zhang, Jun; Liu, Qi; Zheng, Jian; Zhang, Juan

    2015-05-01

    Phytase is a phosphohydrolase considered highly specific for the degradation of phytate to release bound phosphorus for animal consumption and aid in the reduction of environmental nutrient loading. New sources of phytase have been sought that are economically and efficiently productive including the construction of genetically modified (GM) phytase products designed to bypass the costs associated with feed processing. Four monoclonal antibodies (EH10a, FA7, AF9a, and CC1) raised against recombinant Aspergillus niger phyA2 were used to develop a highly specific and sensitive immunochromatographic lateral flow device for rapid detection of transgenic phytase, such as in GM corn. Antibodies sequentially paired and tested along lateral flow strips showed that the EH10a-FA7 antibody pair was able to detect the recombinant yeast-phytase at 5 ng/mL, whereas the AF9a-CC1 antibody pair to GM phytase corn was able to detect at 2 ng/mL. Concurrent to this development, evidence was revealed which suggests that antibody binding sites may be glycosylated. PMID:25901899

  11. Catalysis of Rice Straw Hydrolysis by the Combination of Immobilized Cellulase from Aspergillus niger on ?-Cyclodextrin-Fe3O4 Nanoparticles and Ionic Liquid

    PubMed Central

    Huang, Po-Jung; Chang, Ken-Lin; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto ?-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11?U?g immobilized cellulase?1 at an ionic liquid concentration of 200?mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739?g?h?1?L?1. One of the advantages of immobilized cellulase is high reusabilityit was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15?g?L?1). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  12. Total phenolic contents, antioxidant activities, and lipid fractions from berry pomaces obtained by solid-state fermentation of two Sambucus species with Aspergillus niger.

    PubMed

    Dulf, Francisc Vasile; Vodnar, Dan Cristian; Dulf, Eva-Henrietta; To?a, Monica Ioana

    2015-04-01

    The aim of this study was to investigate the effect of solid-state fermentation (SSF) by Aspergillus niger on phenolic contents and antioxidant activity in Sambucus nigra L. and Sambucus ebulus L. berry pomaces. The effect of fermentation time on the total fats and major lipid classes (neutral and polar) was also investigated. During the SSF, the extractable phenolics increased with 18.82% for S. ebulus L. and 11.11% for S. nigra L. The levels of antioxidant activity of methanolic extracts were also significantly enhanced. The HPLC-MS analysis indicated that the cyanidin 3-sambubioside-5-glucoside is the major phenolic compound in both fermented Sambucus fruit residues. In the early stages of fungal growth, the extracted oils (with TAGs as major lipid fraction) increased with 12% for S. nigra L. and 10.50% for S. ebulus L. The GC-MS analysis showed that the SSF resulted in a slight increase of the linoleic and oleic acids level. PMID:25787023

  13. Identification of InuR, a new Zn(II)2Cys6 transcriptional activator involved in the regulation of inulinolytic genes in Aspergillus niger.

    PubMed

    Yuan, Xiao-Lian; Roubos, Johannes A; van den Hondel, Cees A M J J; Ram, Arthur F J

    2008-01-01

    The expression of inulinolytic genes in Aspergillus niger is co-regulated and induced by inulin and sucrose. We have identified a positive acting transcription factor InuR, which is required for the induced expression of inulinolytic genes. InuR is a member of the fungal specific class of transcription factors of the Zn(II)2Cys6 type. Involvement of InuR in inulin and sucrose metabolism was suspected because of the clustering of inuR gene with sucB, which encodes an intracellular invertase with transfructosylation activity and a putative sugar transporter encoding gene (An15g00310). Deletion of the inuR gene resulted in a strain displaying a severe reduction in growth on inulin and sucrose medium. Northern analysis revealed that expression of inulinolytic and sucrolytic genes, e.g., inuE, inuA, sucA, as well as the putative sugar transporter gene (An15g00310) is dependent on InuR. Genome-wide expression analysis revealed, three additional putative sugar transporters encoding genes (An15g04060, An15g03940 and An17g01710), which were strongly induced by sucrose in an InuR dependent way. In silico analysis of the promoter sequences of strongly InuR regulated genes suggests that InuR might bind as dimer to two CGG triplets, which are separated by eight nucleotides. PMID:17917744

  14. Production of cellulosic ethanol and enzyme from waste fiber sludge using SSF, recycling of hydrolytic enzymes and yeast, and recombinant cellulase-producing Aspergillus niger.

    PubMed

    Cavka, Adnan; Alriksson, Björn; Rose, Shaunita H; van Zyl, Willem H; Jönsson, Leif J

    2014-08-01

    Bioethanol and enzymes were produced from fiber sludges through sequential microbial cultivations. After a first simultaneous saccharification and fermentation (SSF) with yeast, the bioethanol concentrations of sulfate and sulfite fiber sludges were 45.6 and 64.7 g/L, respectively. The second SSF, which included fresh fiber sludges and recycled yeast and enzymes from the first SSF, resulted in ethanol concentrations of 38.3 g/L for sulfate fiber sludge and 24.4 g/L for sulfite fiber sludge. Aspergillus niger carrying the endoglucanase-encoding Cel7B gene of Trichoderma reesei was grown in the spent fiber sludge hydrolysates. The cellulase activities obtained with spent hydrolysates of sulfate and sulfite fiber sludges were 2,700 and 2,900 nkat/mL, respectively. The high cellulase activities produced by using stillage and the significant ethanol concentrations produced in the second SSF suggest that onsite enzyme production and recycling of enzyme are realistic concepts that warrant further attention. PMID:24862324

  15. Effect of Terminalia catappa Fruit Meal Fermented by Aspergillus niger as Replacement of Maize on Growth Performance, Nutrient Digestibility, and Serum Biochemical Profile of Broiler Chickens

    PubMed Central

    Apata, David Friday

    2011-01-01

    A feeding experiment was conducted to investigate the effect of fermented Terminalia catappa fruit meal (FTCM) with Aspergillus niger as replacement for maize on broiler growth performance, nutrient digestibility, and serum biochemical constituents. Dietary maize was replaced by FTCM at 0, 20, 40, 60, or 80%. One hundred and eighty one-day-old Shaver broiler chicks were randomly allocated to the five dietary treatments, three replicate groups of twelve chicks each for a 42-day period. There was no significant difference (P > .05) in the feed intake, weight gain, and feed; gain ratio between the broilers fed on 40% FTCM diet and the control group. The apparent digestibilities of nitrogen, crude fibre, and fat decreased significantly in broilers fed higher levels (>40%) of FTCM replacement diets compared with the control or lower FTCM diets. Serum concentrations of total protein, albumin, and globulin were decreased (P < .05) on 80% FTCM fed broilers. Serum cholesterol, creatinine, and glucose were not significantly (P > .05) altered among treatments. The activities of aspartate and alanine aminotransferases and alkaline phosphatase were significantly (P < .05) increased with higher FTCM replacement. The results indicate that FTCM could replace up to 40% of dietary maize in the diets of broiler chickens without adverse effect on growth performance or serum constituents. PMID:21350670

  16. Catalysis of rice straw hydrolysis by the combination of immobilized cellulase from Aspergillus niger on ?-cyclodextrin-Fe3O4 nanoparticles and ionic liquid.

    PubMed

    Huang, Po-Jung; Chang, Ken-Lin; Hsieh, Jung-Feng; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto ?-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11?U?g immobilized cellulase(-1) at an ionic liquid concentration of 200?mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739?g?h(-1)?L(-1). One of the advantages of immobilized cellulase is high reusability--it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15?g?L(-1)). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  17. Analysis of metal Bioleaching from thermal power plant fly ash by Aspergillus niger 34770 culture supernatant and reduction of phytotoxicity during the process.

    PubMed

    Jadhav, Umesh U; Hocheng, Hong

    2015-01-01

    Aspergillus niger culture supernatant is used for bioleaching process. Before starting bioleaching process, fly ash was washed with distilled water. This removed 100 % sodium, 47 % (±0.45) boron, 38.07 % (±0.12) calcium, 29.89 % (±0.78) magnesium, and 11.8 % (±0.05) potassium. The pH was reduced from 10.5 to 8.5 after water washing. During bioleaching process, around 100 % metal removal was achieved in 4 h for all metals except chromium 93 % (±1.18), nickel 83 % (±0.32), arsenic 78 % (±0.52), and lead 70 % (±0.20). The process parameters including temperature, shaking speed, and solid/liquid ratio were optimized for bioleaching process. Experiments were conducted to evaluate effect of fly ash on growth of mung bean (Vigna radiata). At 20 g/100 ml fly ash concentration no germination of V. radiata seeds was observed. With an increasing concentration of untreated fly ash, a gradual decrease in root/shoot length was observed. After bioleaching process 78 % (±0.19) germination of V. radiata was observed with 20 g/100 ml fly ash. This study will help to develop an efficient process to remove the toxic metals from fly ash. PMID:25349087

  18. The efficacy of disinfectants on abattoirs’ Candida albicans isolates in Niger Delta region

    PubMed Central

    Olorode, Oluwayemisi A

    2012-01-01

    This study was conducted to evaluate the antimicrobial activities of common disinfectants- these are (parachlorometaxylenol) dettol, savlon purit and jik (sodium hypochlorite) on  Candida albicans isolated from displaying and cutting tables in five different abattoirs in Port Harcourt (Niger Delta region); the abattoirs include Trans Amadi, Agip, Woji, Rumuokoro, and Rumuodara. This research was carried out between January 2005 and June 2006. Swab samples were collected from abattoirs cutting tables with sterile swab sticks and immediately transferred and cultured in the laboratory on a selective medium Sabouraud Dextrose Agar (SDA). The disinfectants’ concentrations were prepared at 10%, 20%, 40%, and 70%, in triplicates and the mean values calculated. 0.5 Mc Farland turbidity method of standardization and Agar diffusion method were used for disinfectants testing of the isolates. Statistical analysis of the data showed no significant difference in the effectiveness of these disinfectants at (p<0.05). In conclusion, this study has shown that savlon and dettol were the most potent antimicrobial agents at 10% concentration on  Candida albicans isolates when compared with purit and jik in this study, hence they are good sanitizing agents to be applied on the abattoirs cutting tables, before meat products can be displayed for sale. PMID:24358834

  19. The efficacy of disinfectants on abattoirs' Candida albicans isolates in Niger Delta region.

    PubMed

    Olorode, Oluwayemisi A; Okpokwasli, G Chijioke

    2012-01-01

    This study was conducted to evaluate the antimicrobial activities of common disinfectants- these are (parachlorometaxylenol) dettol, savlon purit and jik (sodium hypochlorite) on  Candida albicans isolated from displaying and cutting tables in five different abattoirs in Port Harcourt (Niger Delta region); the abattoirs include Trans Amadi, Agip, Woji, Rumuokoro, and Rumuodara. This research was carried out between January 2005 and June 2006. Swab samples were collected from abattoirs cutting tables with sterile swab sticks and immediately transferred and cultured in the laboratory on a selective medium Sabouraud Dextrose Agar (SDA). The disinfectants' concentrations were prepared at 10%, 20%, 40%, and 70%, in triplicates and the mean values calculated. 0.5 Mc Farland turbidity method of standardization and Agar diffusion method were used for disinfectants testing of the isolates. Statistical analysis of the data showed no significant difference in the effectiveness of these disinfectants at (p<0.05). In conclusion, this study has shown that savlon and dettol were the most potent antimicrobial agents at 10% concentration on  Candida albicans isolates when compared with purit and jik in this study, hence they are good sanitizing agents to be applied on the abattoirs cutting tables, before meat products can be displayed for sale. PMID:24358834

  20. Selection of Aspergillus flavus isolates for biological control of aflatoxins in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Aspergillus flavus is responsible for producing carcinogenic mycotoxins, the aflatoxins, on corn (maize) and other crops. An additional harmful toxin, cyclopiazonic acid, is produced by some isolates of A. flavus. Several A. flavus strains that do not produce one or both of these mycoto...

  1. Enzymatic Dehairing of Cattlehide with an Alkaline Protease Isolated from Aspergillus tamarii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An enzymatic dehairing protocol based on the alkaline serine protease isolated from Aspergillus tamarii required 16h, and we observed concomitant grain damage. The use of sodium dodecyl sulfate as a pretreatment to remove the lipids from the hide allowed a shortening of the dehairing time to 6 h wi...

  2. Penicillium parvulum and Penicillium georgiense sp. nov. Isolated from the Conidial Heads of Aspergillus Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two new Penicillium species were isolated from peanut-field soils in Georgia. The species were particularly noted because they sporulated on the conidial heads of Aspergillus species. Phenotypic descriptions were prepared using standard media. ITS and lsu-rDNA sequences were made from the new spe...

  3. Azole Resistance in Aspergillus fumigatus Clinical Isolates from an Italian Culture Collection.

    PubMed

    Lazzarini, Cristina; Esposto, Maria Carmela; Prigitano, Anna; Cogliati, Massimo; De Lorenzis, Gabriella; Tortorano, Anna Maria

    2015-01-01

    The aims of the study were to investigate the prevalence of azole resistance among Aspergillus fumigatus clinical isolates. A total of 533 clinical isolates that had been collected between 1995 and 2006, from 441 patients, were screened. No resistance was detected in isolates collected between 1995 and 1997. Starting in 1998, the resistance rate was 6.9%; a total of 24 patients (6.25%) harbored a resistant isolate. The TR34/L98H substitution was found in 21 of 30 tested isolates. PMID:26552980

  4. Aspergillus, Penicillium and Talaromyces isolated from house dust samples collected around the world

    PubMed Central

    Visagie, C.M.; Hirooka, Y.; Tanney, J.B.; Whitfield, E.; Mwange, K.; Meijer, M.; Amend, A.S.; Seifert, K.A.; Samson, R.A.

    2014-01-01

    As part of a worldwide survey of the indoor mycobiota, dust was collected from nine countries. Analyses of dust samples included the culture-dependent dilution-to-extinction method and the culture-independent 454-pyrosequencing. Of the 7 904 isolates, 2 717 isolates were identified as belonging to Aspergillus, Penicillium and Talaromyces. The aim of this study was to identify isolates to species level and describe the new species found. Secondly, we wanted to create a reliable reference sequence database to be used for next-generation sequencing projects. Isolates represented 59 Aspergillus species, including eight undescribed species, 49 Penicillium species of which seven were undescribed and 18 Talaromyces species including three described here as new. In total, 568 ITS barcodes were generated, and 391 β-tubulin and 507 calmodulin sequences, which serve as alternative identification markers. PMID:25492981

  5. Aspergillus, Penicillium and Talaromyces isolated from house dust samples collected around the world.

    PubMed

    Visagie, C M; Hirooka, Y; Tanney, J B; Whitfield, E; Mwange, K; Meijer, M; Amend, A S; Seifert, K A; Samson, R A

    2014-06-01

    As part of a worldwide survey of the indoor mycobiota, dust was collected from nine countries. Analyses of dust samples included the culture-dependent dilution-to-extinction method and the culture-independent 454-pyrosequencing. Of the 7?904 isolates, 2?717 isolates were identified as belonging to Aspergillus, Penicillium and Talaromyces. The aim of this study was to identify isolates to species level and describe the new species found. Secondly, we wanted to create a reliable reference sequence database to be used for next-generation sequencing projects. Isolates represented 59 Aspergillus species, including eight undescribed species, 49 Penicillium species of which seven were undescribed and 18 Talaromyces species including three described here as new. In total, 568 ITS barcodes were generated, and 391 ?-tubulin and 507 calmodulin sequences, which serve as alternative identification markers. PMID:25492981

  6. Environmental Isolates of Azole-Resistant Aspergillus fumigatus in Germany

    PubMed Central

    Tnnermann, Jana; Dudakova, Anna; Tangwattanachuleeporn, Marut; Weig, Michael; Gro, Uwe

    2015-01-01

    Azole antifungal drug resistance in Aspergillus fumigatus is an emerging problem in several parts of the world. Here we investigated the distribution of such strains in soils from Germany. At a general positivity rate of 12%, most prevalently, we found strains with the TR34/L98H and TR46/Y121F/T289A alleles, dispersed along a corridor across northern Germany. Comparison of the distributions of resistance alleles and genotypes between environment and clinical samples suggests the presence of local clinical clusters. PMID:25941229

  7. Isolation and Characterization of Sexual Spore Pigments from Aspergillus nidulans

    PubMed Central

    Brown, Daren W.; Salvo, Joseph J.

    1994-01-01

    The homothallic ascomycete Aspergillus nidulans produces two types of pigmented spores: conidia and ascospores. The synthesis and localization of the spore pigments is developmentally regulated and occurs in specialized cell types. On the basis of spectroscopic evidence, we propose that the major ascospore pigment of A. nidulans (ascoquinone A) is a novel dimeric hydroxylated anthraquinone. The structure of ascoquinone A, as well as a comparison to model compounds, suggests that it is the product of a polyketide synthase. Previous studies have revealed that the conidial pigments from A. nidulans and a related Aspergillus species (A. parasiticus) also appear to be produced via polymerization of polyketide precursors (D. W. Brown, F. M. Hauser, R. Tommasi, S. Corlett, and J. J. Salvo, Tetrahedron Lett. 34:419-422, 1993; M. E. Mayorga and W. E. Timberlake, Mol. Gen. Genet. 235:205-212, 1992). The structural similarity between the ascospore pigment and the toxic anthraquinone norsolorinic acid, the first stable intermediate in the aflatoxin pathway, suggests an evolutionary relationship between the respective polyketide synthase systems. PMID:16349224

  8. The Transcriptional Repressor TupA in Aspergillus niger Is Involved in Controlling Gene Expression Related to Cell Wall Biosynthesis, Development, and Nitrogen Source Availability

    PubMed Central

    Schachtschabel, Doreen; Arentshorst, Mark; Nitsche, Benjamin M.; Morris, Sam; Nielsen, Kristian F.; van den Hondel, Cees A. M. J. J.; Klis, Frans M.; Ram, Arthur F. J.

    2013-01-01

    The Tup1-Cyc8 (Ssn6) complex is a well characterized and conserved general transcriptional repressor complex in eukaryotic cells. Here, we report the identification of the Tup1 (TupA) homolog in the filamentous fungus Aspergillus niger in a genetic screen for mutants with a constitutive expression of the agsA gene. The agsA gene encodes a putative alpha-glucan synthase, which is induced in response to cell wall stress in A. niger. Apart from the constitutive expression of agsA, the selected mutant was also found to produce an unknown pigment at high temperatures. Complementation analysis with a genomic library showed that the tupA gene could complement the phenotypes of the mutant. Screening of a collection of 240 mutants with constitutive expression of agsA identified sixteen additional pigment-secreting mutants, which were all mutated in the tupA gene. The phenotypes of the tupA mutants were very similar to the phenotypes of a tupA deletion strain. Further analysis of the tupA-17 mutant and the ΔtupA mutant revealed that TupA is also required for normal growth and morphogenesis. The production of the pigment at 37°C is nitrogen source-dependent and repressed by ammonium. Genome-wide expression analysis of the tupA mutant during exponential growth revealed derepression of a large group of diverse genes, including genes related to development and cell wall biosynthesis, and also protease-encoding genes that are normally repressed by ammonium. Comparison of the transcriptome of up-regulated genes in the tupA mutant showed limited overlap with the transcriptome of caspofungin-induced cell wall stress-related genes, suggesting that TupA is not a general suppressor of cell wall stress-induced genes. We propose that TupA is an important repressor of genes related to development and nitrogen metabolism. PMID:24205111

  9. Systems Approaches to Predict the Functions of Glycoside Hydrolases during the Life Cycle of Aspergillus niger Using Developmental Mutants ∆brlA and ∆flbA

    PubMed Central

    van Munster, Jolanda M.; Nitsche, Benjamin M.; Akeroyd, Michiel; Dijkhuizen, Lubbert; van der Maarel, Marc J. E. C.; Ram, Arthur F. J.

    2015-01-01

    Background The filamentous fungus Aspergillus niger encounters carbon starvation in nature as well as during industrial fermentations. In response, regulatory networks initiate and control autolysis and sporulation. Carbohydrate-active enzymes play an important role in these processes, for example by modifying cell walls during spore cell wall biogenesis or in cell wall degradation connected to autolysis. Results In this study, we used developmental mutants (ΔflbA and ΔbrlA) which are characterized by an aconidial phenotype when grown on a plate, but also in bioreactor-controlled submerged cultivations during carbon starvation. By comparing the transcriptomes, proteomes, enzyme activities and the fungal cell wall compositions of a wild type A. niger strain and these developmental mutants during carbon starvation, a global overview of the function of carbohydrate-active enzymes is provided. Seven genes encoding carbohydrate-active enzymes, including cfcA, were expressed during starvation in all strains; they may encode enzymes involved in cell wall recycling. Genes expressed in the wild-type during starvation, but not in the developmental mutants are likely involved in conidiogenesis. Eighteen of such genes were identified, including characterized sporulation-specific chitinases and An15g02350, member of the recently identified carbohydrate-active enzyme family AA11. Eight of the eighteen genes were also expressed, independent of FlbA or BrlA, in vegetative mycelium, indicating that they also have a role during vegetative growth. The ΔflbA strain had a reduced specific growth rate, an increased chitin content of the cell wall and specific expression of genes that are induced in response to cell wall stress, indicating that integrity of the cell wall of strain ΔflbA is reduced. Conclusion The combination of the developmental mutants ΔflbA and ΔbrlA resulted in the identification of enzymes involved in cell wall recycling and sporulation-specific cell wall modification, which contributes to understanding cell wall remodeling mechanisms during development. PMID:25629352

  10. Mapping the structural requirements of inducers and substrates for decarboxylation of weak acid preservatives by the food spoilage mould Aspergillus niger.

    PubMed

    Stratford, Malcolm; Plumridge, Andrew; Pleasants, Mike W; Novodvorska, Michaela; Baker-Glenn, Charles A G; Pattenden, Gerald; Archer, David B

    2012-07-16

    Moulds are able to cause spoilage in preserved foods through degradation of the preservatives using the Pad-decarboxylation system. This causes, for example, decarboxylation of the preservative sorbic acid to 1,3-pentadiene, a volatile compound with a kerosene-like odour. Neither the natural role of this system nor the range of potential substrates has yet been reported. The Pad-decarboxylation system, encoded by a gene cluster in germinating spores of the mould Aspergillus niger, involves activity by two decarboxylases, PadA1 and OhbA1, and a regulator, SdrA, acting pleiotropically on sorbic acid and cinnamic acid. The structural features of compounds important for the induction of Pad-decarboxylation at both transcriptional and functionality levels were investigated by rtPCR and GCMS. Sorbic and cinnamic acids served as transcriptional inducers but ferulic, coumaric and hexanoic acids did not. 2,3,4,5,6-Pentafluorocinnamic acid was a substrate for the enzyme but had no inducer function; it was used to distinguish induction and competence for decarboxylation in combination with the analogue chemicals. The structural requirements for the substrates of the Pad-decarboxylation system were probed using a variety of sorbic and cinnamic acid analogues. High decarboxylation activity, ~100% conversion of 1mM substrates, required a mono-carboxylic acid with an alkenyl double bond in the trans (E)-configuration at position C2, further unsaturation at C4, and an overall molecular length between 6.5 and 9. Polar groups on the phenyl ring of cinnamic acid abolished activity (no conversion). Furthermore, several compounds were shown to block Pad-decarboxylation. These compounds, primarily aldehyde analogues of active substrates, may serve to reduce food spoilage by moulds such as A. niger. The possible ecological role of Pad-decarboxylation of spore self-inhibitors is unlikely and the most probable role for Pad-decarboxylation is to remove cinnamic acid-type inhibitors from plant material and allow uninhibited germination and growth of mould spores. PMID:22726726

  11. First isolation of a novel thermostable antifungal peptide secreted by Aspergillus clavatus.

    PubMed

    Skouri-Gargouri, Houda; Gargouri, Ali

    2008-11-01

    A novel antifungal peptide produced by an indigenous fungal strain (VR) of Aspergillus clavatus was purified. The antifungal peptide was enriched in the supernatant after heat treatment at 70 degrees C. The thermostable character was exploited in the first purification step, as purified peptide was obtained after ultrafiltration and reverse phase-HPLC on C18 column application. The purified peptide named "AcAFP" for A. clavatus antifungal peptide, has molecular mass of 5773Da determined by MALDI-ToF spectrometry. The N-terminal sequence showed a notable identity to the limited family of antifungal peptides produced by ascomycetes fungi. The AcAFP activity remains intact even after heat treatment at 100 degrees C for 1h confirming its thermostability. It exhibits a strong inhibitory activity against mycelial growth of several serious human and plant pathogenic fungi: Fusariuym oxysporum, Fusarium solani, Aspergillus niger, Botrytis cinerea, Alternaria solani, whereas AcAFP did not affect yeast and bacterial growth. PMID:18687373

  12. Molecular screening of 246 Portuguese Aspergillus isolates among different clinical and environmental sources.

    PubMed

    Sabino, Raquel; Verssimo, Cristina; Parada, Helena; Brando, Joo; Viegas, Carla; Carolino, Elisabete; Clemons, Karl V; Stevens, David A

    2014-07-01

    Clinical and environmental samples from Portugal were screened for the presence of Aspergillus and the distributions of the species complexes were determined in order to understand how their distributions differ based on their source. Fifty-seven Aspergillus isolates from clinical samples were collected from 10 health institutions. Six species complexes were detected by internal transcribed spacer sequencing; Fumigati, Flavi, and Nigri were found most frequently (50.9%, 21.0%, and 15.8%, respectively). ?-tubulin and calmodulin sequencing resulted in seven cryptic species (A. awamorii, A. brasiliensis, A. fructus, A. lentulus, A. sydowii, A. tubingensis, Emericella echinulata) being identified among the 57 isolates. Thirty-nine isolates of Aspergillus were recovered from beach sand and poultry farms, 31 from swine farms, and 80 from hospital environments, for a total 189 isolates. Eleven species complexes were found in these 189 isolates, and those belonging to the Versicolores species complex were found most frequently (23.8%). There was a significant association between the different environmental sources and distribution of the species complexes; the hospital environment had greater variability of species complexes than other environmental locations. A high prevalence of cryptic species within the Circumdati complex was detected in several environments; from the isolates analyzed, at least four cryptic species were identified, most of them growing at 37C. Because Aspergillus species complexes have different susceptibilities to antifungals, knowing the species-complex epidemiology for each setting, as well as the identification of cryptic species among the collected clinical isolates, is important. This may allow preventive and corrective measures to be taken, which may result in decreased exposure to those organisms and a better prognosis. PMID:24847040

  13. Molecular characterization of Aspergillus infections in an Iranian educational hospital using RAPD-PCR method

    PubMed Central

    Diba, Kambiz; Makhdoomi, Khadijeh; Mirhendi, Hossein

    2014-01-01

    Objective(s): The nosocomial infections by Aspergillus species are associated with constructions and increased dust loads in hospital indoors. Our main object was to find the environmental sources of Aspergillus species causing hospital acquired infections. Materials and Methods: The clinical and environmental samplings were performed during 18 months from spring 2010 to summer 2011 in Imam educational hospital, Urmia, Iran. A morphological diagnosis was performed including microscopic characterization of isolated aspergillus from cultured specimens and polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) for the identification in the level of species. Random amplified polymorphic DNA - PCR RAPD-PCR using random primers for rDNA gene was performed to compare Aspergillus isolates of clinical cases with the relevant environmental sources. Results: Use of RAPD method resulted various differential patterns, so that some Aspergillus isolates from the clinical and hospital indoor were completely matched (matched pairs) and some other Aspergillus isolates were not matched. In the case of matched pairs, Aspergillus niger and A. flavus isolated from broncoalveolar lavage and sinus discharge were relevant to those of air conditioner and walls surfaces, respectively. Conclusion: The hospital sources for the Aspergillus clinical isolates included air condition and walls. RAPD-PCR analysis can play a trivial role to find the hospital sources of Aspergillus clinical isolates. PMID:25691939

  14. Pectinase production by Aspergillus niger using banana (Musa balbisiana) peel as substrate and its effect on clarification of banana juice.

    PubMed

    Barman, Sumi; Sit, Nandan; Badwaik, Laxmikant S; Deka, Sankar C

    2015-06-01

    Optimization of substrate concentration, time of incubation and temperature for crude pectinase production from A. niger was carried out using Bhimkol banana (Musa balbisiana) peel as substrate. The crude pectinase produced was partially purified using ethanol and effectiveness of crude and partially purified pectinase was studied for banana juice clarification. The optimum substrate concentration, incubation time and temperature of incubation were 8.07%, 65.82h and 32.37C respectively, and the polygalacturonase (PG) activity achieved was 6.6 U/ml for crude pectinase. The partially purified enzyme showed more than 3 times of polygalacturonase activity as compared to the crude enzyme. The SDS-PAGE profile showed that the molecular weight of proteins present in the different pectinases varied from 34 to 42kDa. The study further revealed that highest clarification was achieved when raw banana juice was incubated for 60min with 2% concentration of partially purified pectinase and the absorbance obtained was 0.10. PMID:26028740

  15. The roles of the zinc finger transcription factors XlnR, ClrA and ClrB in the breakdown of lignocellulose by Aspergillus niger.

    PubMed

    Raulo, Roxane; Kokolski, Matthew; Archer, David B

    2016-12-01

    Genes encoding the key transcription factors (TF) XlnR, ClrA and ClrB were deleted from Aspergillus niger and the resulting strains were assessed for growth on glucose and wheat straw, transcription of genes encoding glycosyl hydrolases and saccharification activity. Growth of all mutant strains, based in straw on measurement of pH and assay of glucosamine, was impaired in relation to the wild-type (WT) strain although deletion of clrA had less effect than deletion of xlnR or clrB. Release of sugars from wheat straw was also lowered when culture filtrates from TF deletion strains were compared with WT culture filtrates. Transcript levels of cbhA, eglC and xynA were measured in all strains in glucose and wheat straw media in batch culture with and without pH control. Transcript levels from cbhA and eglC were lowered in all mutant strains compared to WT although the impact of deleting clrA was not pronounced with expression of eglC and had no effect on xynA. The impact on transcription was not related to changes in pH. In addition to impaired growth on wheat straw, the ΔxlnR strain was sensitive to oxidative stress and displayed cell wall defects in the glucose condition suggesting additional roles for XlnR. The characterisation of TFs, such as ClrB, provides new areas of improvement for industrial processes for production of second generation biofuels. PMID:26780227

  16. Shifting the pH Profile of Aspergillus niger PhyA Phytase To Match the Stomach pH Enhances Its Effectiveness as an Animal Feed Additive

    PubMed Central

    Kim, Taewan; Mullaney, Edward J.; Porres, Jesus M.; Roneker, Karl R.; Crowe, Sarah; Rice, Sarah; Ko, Taegu; Ullah, Abul H. J.; Daly, Catherine B.; Welch, Ross; Lei, Xin Gen

    2006-01-01

    Environmental pollution by phosphorus from animal waste is a major problem in agriculture because simple-stomached animals, such as swine, poultry, and fish, cannot digest phosphorus (as phytate) present in plant feeds. To alleviate this problem, a phytase from Aspergillus niger PhyA is widely used as a feed additive to hydrolyze phytate-phosphorus. However, it has the lowest relative activity at the pH of the stomach (3.5), where the hydrolysis occurs. Our objective was to shift the pH optima of PhyA to match the stomach condition by substituting amino acids in the substrate-binding site with different charges and polarities. Based on the crystal structure of PhyA, we prepared 21 single or multiple mutants at Q50, K91, K94, E228, D262, K300, and K301 and expressed them in Pichia pastoris yeast. The wild-type (WT) PhyA showed the unique bihump, two-pH-optima profile, whereas 17 mutants lost one pH optimum or shifted the pH optimum from pH 5.5 to the more acidic side. The mutant E228K exhibited the best overall changes, with a shift of pH optimum to 3.8 and 266% greater (P < 0.05) hydrolysis of soy phytate at pH 3.5 than the WT enzyme. The improved efficacy of the enzyme was confirmed in an animal feed trial and was characterized by biochemical analysis of the purified mutant enzymes. In conclusion, it is feasible to improve the function of PhyA phytase under stomach pH conditions by rational protein engineering. PMID:16751556

  17. Shifting the pH profile of Aspergillus niger PhyA phytase to match the stomach pH enhances its effectiveness as an animal feed additive.

    PubMed

    Kim, Taewan; Mullaney, Edward J; Porres, Jesus M; Roneker, Karl R; Crowe, Sarah; Rice, Sarah; Ko, Taegu; Ullah, Abul H J; Daly, Catherine B; Welch, Ross; Lei, Xin Gen

    2006-06-01

    Environmental pollution by phosphorus from animal waste is a major problem in agriculture because simple-stomached animals, such as swine, poultry, and fish, cannot digest phosphorus (as phytate) present in plant feeds. To alleviate this problem, a phytase from Aspergillus niger PhyA is widely used as a feed additive to hydrolyze phytate-phosphorus. However, it has the lowest relative activity at the pH of the stomach (3.5), where the hydrolysis occurs. Our objective was to shift the pH optima of PhyA to match the stomach condition by substituting amino acids in the substrate-binding site with different charges and polarities. Based on the crystal structure of PhyA, we prepared 21 single or multiple mutants at Q50, K91, K94, E228, D262, K300, and K301 and expressed them in Pichia pastoris yeast. The wild-type (WT) PhyA showed the unique bihump, two-pH-optima profile, whereas 17 mutants lost one pH optimum or shifted the pH optimum from pH 5.5 to the more acidic side. The mutant E228K exhibited the best overall changes, with a shift of pH optimum to 3.8 and 266% greater (P < 0.05) hydrolysis of soy phytate at pH 3.5 than the WT enzyme. The improved efficacy of the enzyme was confirmed in an animal feed trial and was characterized by biochemical analysis of the purified mutant enzymes. In conclusion, it is feasible to improve the function of PhyA phytase under stomach pH conditions by rational protein engineering. PMID:16751556

  18. Optimization of Aspergillus niger rock phosphate solubilization in solid-state fermentation and use of the resulting product as a P fertilizer.

    PubMed

    Mendes, Gilberto de Oliveira; da Silva, Nina Morena Rgo Muniz; Anastcio, Thalita Cardoso; Vassilev, Nikolay Bojkov; Ribeiro, Jos Ivo; da Silva, Ivo Ribeiro; Costa, Maurcio Dutra

    2015-11-01

    A biotechnological strategy for the production of an alternative P fertilizer is described in this work. The fertilizer was produced through rock phosphate (RP) solubilization by Aspergillus niger in a solid-state fermentation (SSF) with sugarcane bagasse as substrate. SSF conditions were optimized by the surface response methodology after an initial screening of factors with significant effect on RP solubilization. The optimized levels of the factors were 865?mg of biochar, 250?mg of RP, 270?mg of sucrose and 6.2?ml of water per gram of bagasse. At this optimal setting, 8.6?mg of water-soluble P per gram of bagasse was achieved, representing an increase of 2.4 times over the non-optimized condition. The optimized SSF product was partially incinerated at 350C (SB-350) and 500C (SB-500) to reduce its volume and, consequently, increase P concentration. The post-processed formulations of the SSF product were evaluated in a soil-plant experiment. The formulations SB-350 and SB-500 increased the growth and P uptake of common bean plants (Phaseolus vulgaris?L.) when compared with the non-treated RP. Furthermore, these two formulations had a yield relative to triple superphosphate of 60% (on a dry mass basis). Besides increasing P concentration, incineration improved the SSF product performance probably by decreasing microbial immobilization of nutrients during the decomposition of the remaining SSF substrate. The process proposed is a promising alternative for the management of P fertilization since it enables the utilization of low-solubility RPs and relies on the use of inexpensive materials. PMID:26112323

  19. Optimization of Aspergillus niger rock phosphate solubilization in solid-state fermentation and use of the resulting product as a P fertilizer

    PubMed Central

    Mendes, Gilberto de Oliveira; da Silva, Nina Morena Rêgo Muniz; Anastácio, Thalita Cardoso; Vassilev, Nikolay Bojkov; Ribeiro, José Ivo; da Silva, Ivo Ribeiro; Costa, Maurício Dutra

    2015-01-01

    A biotechnological strategy for the production of an alternative P fertilizer is described in this work. The fertilizer was produced through rock phosphate (RP) solubilization by Aspergillus niger in a solid-state fermentation (SSF) with sugarcane bagasse as substrate. SSF conditions were optimized by the surface response methodology after an initial screening of factors with significant effect on RP solubilization. The optimized levels of the factors were 865 mg of biochar, 250 mg of RP, 270 mg of sucrose and 6.2 ml of water per gram of bagasse. At this optimal setting, 8.6 mg of water-soluble P per gram of bagasse was achieved, representing an increase of 2.4 times over the non-optimized condition. The optimized SSF product was partially incinerated at 350°C (SB-350) and 500°C (SB-500) to reduce its volume and, consequently, increase P concentration. The post-processed formulations of the SSF product were evaluated in a soil–plant experiment. The formulations SB-350 and SB-500 increased the growth and P uptake of common bean plants (Phaseolus vulgaris L.) when compared with the non-treated RP. Furthermore, these two formulations had a yield relative to triple superphosphate of 60% (on a dry mass basis). Besides increasing P concentration, incineration improved the SSF product performance probably by decreasing microbial immobilization of nutrients during the decomposition of the remaining SSF substrate. The process proposed is a promising alternative for the management of P fertilization since it enables the utilization of low-solubility RPs and relies on the use of inexpensive materials. PMID:26112323

  20. Molecular characterisation of Aspergillus flavus isolates from peanut fields in India using AFLP

    PubMed Central

    Singh, Diwakar; Radhakrishnan, T.; Kumar, Vinod; Bagwan, N.B.; Basu, M.S.; Dobaria, J.R.; Mishra, Gyan P.; Chanda, S.V.

    2015-01-01

    Aflatoxin contamination of peanut, due to infection by Aspergillus flavus, is a major problem of rain-fed agriculture in India. In the present study, molecular characterisation of 187 Aspergillus flavus isolates, which were sampled from the peanut fields of Gujarat state in India, was performed using AFLP markers. On a pooled cluster analysis, the markers could successfully discriminate among the ‘A’, ‘B’ and ‘G’ group A. flavus isolates. PCoA analysis also showed equivalent results to the cluster analysis. Most of the isolates from one district could be clustered together, which indicated genetic similarity among the isolates. Further, a lot of genetic variability was observed within a district and within a group. The results of AMOVA test revealed that the variance within a population (84%) was more than that between two populations (16%). The isolates, when tested by indirect competitive ELISA, showed about 68.5% of them to be atoxigenic. Composite analysis between the aflatoxin production and AFLP data was found to be ineffective in separating the isolate types by aflatoxigenicity. Certain unique fragments, with respect to individual isolates, were also identified that may be used for development of SCAR marker to aid in rapid and precise identification of isolates. PMID:26413047

  1. Molecular characterisation of Aspergillus flavus isolates from peanut fields in India using AFLP.

    PubMed

    Singh, Diwakar; Radhakrishnan, T; Kumar, Vinod; Bagwan, N B; Basu, M S; Dobaria, J R; Mishra, Gyan P; Chanda, S V

    2015-01-01

    Aflatoxin contamination of peanut, due to infection by Aspergillus flavus, is a major problem of rain-fed agriculture in India. In the present study, molecular characterisation of 187 Aspergillus flavus isolates, which were sampled from the peanut fields of Gujarat state in India, was performed using AFLP markers. On a pooled cluster analysis, the markers could successfully discriminate among the 'A', 'B' and 'G' group A. flavus isolates. PCoA analysis also showed equivalent results to the cluster analysis. Most of the isolates from one district could be clustered together, which indicated genetic similarity among the isolates. Further, a lot of genetic variability was observed within a district and within a group. The results of AMOVA test revealed that the variance within a population (84%) was more than that between two populations (16%). The isolates, when tested by indirect competitive ELISA, showed about 68.5% of them to be atoxigenic. Composite analysis between the aflatoxin production and AFLP data was found to be ineffective in separating the isolate types by aflatoxigenicity. Certain unique fragments, with respect to individual isolates, were also identified that may be used for development of SCAR marker to aid in rapid and precise identification of isolates. PMID:26413047

  2. A new citrinin dimer isolated from Aspergillus terreus strain ZDF21.

    PubMed

    Dame, Zerihun T; Suwannarach, Nakarin; Lumyong, Saisamorn; Laatsch, Hartmut

    2015-04-01

    Dicitrinin E (1), a new citrinin dimer, together with the known metabolites, dicitrinin A (2), citrinin (3), and fumitremorgin C (4), were isolated from the broth culture of Aspergillus terreus strain ZDF21. The structure of dicitrinin E (1) was elucidated through detailed analysis of 1D and 2D NMR experiments, CD and mass spectra The cytotoxicity of 1 was tested against larvae of Artemia salina. PMID:25973492

  3. A new diketopiperazine alkaloid isolated from an algicolous Aspergillus flavus strain.

    PubMed

    Lin, Aiqun; Fang, Yuchun; Zhu, Tianjiao; Gu, Qianqun; Zhu, Weiming

    2008-04-01

    A new diketopiperazine alkaloid containing the uncommon amino acid L-7, 9-dihydroxy-8-methoxyphenylalanine (1), has been isolated from the algicolous Aspergillus flavus strain. The structure of 1 including the absolute stereochemistry was determined by spectroscopic data and chemical means. Compound 1 showed weak cytotoxicity against HL-60 cell lines with an IC50 value of 36.5 microg/ml. PMID:18468397

  4. Extracellular Xylanolytic and Pectinolytic Hydrolase Production by Aspergillus flavus Isolates Contributes to Crop Invasion

    PubMed Central

    Mellon, Jay E.

    2015-01-01

    Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium utilizing larch xylan as a sole carbon substrate. Four of the tested isolates produced reasonably high levels of esterase activity, while the atoxigenic biocontrol agent NRRL 21882 isolate esterase level was significantly lower than the others. Atoxigenic A. flavus isolates 19, 22, K49, AF36 (the latter two are biocontrol agents) and toxigenic AF13 produced copious levels of pectinolytic activity when grown on a pectin medium. The pectinolytic activity levels of the atoxigenic A. flavus 17 and NRRL 21882 isolates were significantly lower than the other tested isolates. In addition, A. flavus isolates that displayed high levels of pectinolytic activity in the plate assay produced high levels of endopolygalacturonase (pectinase) P2c, as ascertained by isoelectric focusing electrophoresis. Isolate NRRL 21882 displayed low levels of both pectinase P2c and pectin methyl esterase. A. flavus appears capable of producing these hydrolytic enzymes irrespective of aflatoxin production. This ability of atoxigenic isolates to produce xylanolytic and pectinolytic hydrolases mimics that of toxigenic isolates and, therefore, contributes to the ability of atoxigenic isolates to occupy the same niche as A. flavus toxigenic isolates. PMID:26295409

  5. Extracellular Xylanolytic and Pectinolytic Hydrolase Production by Aspergillus flavus Isolates Contributes to Crop Invasion.

    PubMed

    Mellon, Jay E

    2015-08-01

    Several atoxigenic Aspergillus flavus isolates, including some being used as biocontrol agents, and one toxigenic isolate were surveyed for the ability to produce extracellular xylanolytic and pectinolytic hydrolases. All of the tested isolates displayed good production of endoxylanases when grown on a medium utilizing larch xylan as a sole carbon substrate. Four of the tested isolates produced reasonably high levels of esterase activity, while the atoxigenic biocontrol agent NRRL 21882 isolate esterase level was significantly lower than the others. Atoxigenic A. flavus isolates 19, 22, K49, AF36 (the latter two are biocontrol agents) and toxigenic AF13 produced copious levels of pectinolytic activity when grown on a pectin medium. The pectinolytic activity levels of the atoxigenic A. flavus 17 and NRRL 21882 isolates were significantly lower than the other tested isolates. In addition, A. flavus isolates that displayed high levels of pectinolytic activity in the plate assay produced high levels of endopolygalacturonase (pectinase) P2c, as ascertained by isoelectric focusing electrophoresis. Isolate NRRL 21882 displayed low levels of both pectinase P2c and pectin methyl esterase. A. flavus appears capable of producing these hydrolytic enzymes irrespective of aflatoxin production. This ability of atoxigenic isolates to produce xylanolytic and pectinolytic hydrolases mimics that of toxigenic isolates and, therefore, contributes to the ability of atoxigenic isolates to occupy the same niche as A. flavus toxigenic isolates. PMID:26295409

  6. Aerial Prevalence of Aspergillus calidoustus Isolates in and around a Tertiary Care Hospital in Kuwait and Assessment of Their Pathogenicity

    PubMed Central

    Ahmad, Suhail; Joseph, Leena

    2014-01-01

    Seven Aspergillus calidoustus isolates from 486 Aspergillus spp. isolates (1.4% overall prevalence) from outdoor/indoor air samples and one isolate from the bronchoalveolar lavage fluid of a patient with pneumonia were obtained. These 8 isolates exhibited reduced susceptibility to triazoles. Preliminary pathogenicity data from BALB/c mice suggest that A. calidoustus can persist in tissues for long periods without causing mortality. Further studies using graded doses of inoculum and immunosuppression models are warranted to gain an understanding of the factors associated with its pathogenicity and virulence. PMID:24920775

  7. Amylose-like polysaccharide accumulation and hyphal cell-surface structure in relation to citric acid production by Aspergillus niger in shake culture.

    PubMed

    Kirimura, K; Yusa, S; Rugsaseel, S; Nakagawa, H; Osumi, M; Usami, S

    1999-09-01

    When 120 mg glucose/ml was used as a carbon source, in shake culture Aspergillus niger Yang no. 2 maximally produced only 15.4 mg citric acid/ml but accumulated 3.0 mg extracellular polysaccharide/ml. The polysaccharide secreted by mycelia of Yang no. 2 in shake culture was confirmed to be an amylose-like alpha-1,4-glucan by hydrolysis analysis with acid, amylase and glucoamylase. However, in static cultures, such as semisolid and surface cultures free from physical stresses caused by shaking damage, Yang no. 2 produced more citric acid but did not accumulate the polysaccharide. With cultivation time in shake culture, the amount of extracellular polysaccharide and the viscosity of the culture broth increased. The increase of shaking speed caused a remarkable increase in the accumulation of extracellular polysaccharide, e.g. 11.2 mg extracellular polysaccharide/ml was accumulated in the medium at a shaking speed of 200 rpm. The addition of 2.0 mg carboxymethylcellulose (CMC)/ml as a viscous additive to the medium reduced drastically the amount of extracellular polysaccharide accumulated to 1.5 mg/ml, but increased the citric acid produced to 52.0 mg/ml. However, intracellular polysaccharide accumulation kept up a steady rate of 0.26 microgram/mg dried mycelium through the entire period of cultivation. The addition of 3.0 mg polysaccharide/ml purified from the culture broth to the medium at the start of a culture resulted in a decrease of extracellular polysaccharide accumulation but an increase of citric acid accumulation. From electronmicroscopic observation, cell surfaces of hyphae cultivated with CMC were smooth, while hyphae cultivated without CMC had fibrous and granular polysaccharide on the cell surface. These results suggested that Yang no. 2 secreted the polysaccharide on the cell surface as a viscous substance and/or a shock absorber to protect itself from physical stresses caused by shaking damage in shake culture. PMID:10531655

  8. Chemical investigation of metabolites produced by an endophytic Aspergillus sp. isolated from Limonia acidissima.

    PubMed

    Siriwardane, A M D A; Kumar, N Savitri; Jayasinghe, Lalith; Fujimoto, Yoshinori

    2015-01-01

    Endophytic fungi are considered as a good source to produce important secondary metabolites with interesting bioactivities. In a continuation of our studies towards the search for environmentally friendly bioactive compounds from Sri Lankan flora, we investigated the secondary metabolites produced by the endophytic fungi Aspergillus sp. isolated from the seeds of the popular edible fruit Limonia acidissima L. of the family Rutaceae. The pure culture of the Aspergillus sp. was grown on potato dextrose broth media. After 4 weeks fermentation, fungal media were extracted with organic solvents. Chromatographic separation of the fungal extracts over silica gel, Sephadex LH-20 and RP-HPLC furnished flavasperone (1), rubrofusarin B (2), aurasperone A (3), fonsecinone D (4) and aurasperone B (5). Compounds 1-4 showed moderate activities in brine shrimp toxicity assay. This is the first report of the (13)C NMR data of compounds 4 and 5. PMID:25809933

  9. Molecular identification and antifungal susceptibility profile of Aspergillus flavus isolates recovered from clinical specimens in Kuwait

    PubMed Central

    2013-01-01

    Background Within the genus Aspergillus, A. flavus is the second most important species of clinical significance. It is predominantly associated with infections involving sinuses, eye and skin, mostly in geographic regions with hot and arid climate, including the Middle East. Recent reports on emergence of resistance to triazoles among Aspergillus spp. is a cause of concern for treatment of patients with invasive aspergillosis. In this study we present data on genetic characterization and antifungal susceptibility profile of clinical and environmental isolates of A. flavus. Methods Ninety-nine Aspergillus section Flavi isolates, originating from clinical (n=92) and environmental (n=7) sources, initially identified by morphological characteristics, were analyzed by partial sequencing of ?-tubulin and calmodulin gene fragments and their susceptibilities to six antifungal agents was determined by Etest on RPMI1640 and Muller-Hinton agar media. Etest minimum inhibitory concentrations (MICs) of amphotericin B and voriconazole were also compared with zone of inhibition diameters obtained by disc diffusion test on RPMI agar medium. Results The identity of all clinical and environmental isolates was confirmed as A. flavus species by combined analysis of ?-tubulin and calmodulin genes. The mean MIC90 (?g/ml) values on RPMI medium for amphotericin B, voriconazole, posaconazole, anidulafungin, micafungin and caspofungin were 3, 0.25, 0.25, 0.002, 0.002 and 0.032, respectively. No environmental isolate exhibited MIC value of >2 ?g/ml for amphotericin B. For clinical isolates, the zone of inhibition diameters for amphotericin B and voriconazole ranged from 716 mm and 2434 mm, respectively. Linear regression analysis between Etest MIC values and disk diffusion diameters revealed a significant inverse correlation with amphotericin B (p <0.001) and voriconazole (p<0.003). Conclusions The ?-tubulin and calmodulin gene sequences confirmed that all 92 clinical isolates identified phenotypically belonged to A. flavus taxon, thus suggesting that the other species within Aspergillus section Flavi are of little clinical significance. Triazoles and echinocandins showed very good in vitro activity against the A. flavus, however, 10% clinical isolates showed MICs of >2 ?g/ml for amphotericin B. PMID:23496810

  10. Purification and some properties of an Aspergillus niger beta-apiosidase from an enzyme preparation hydrolyzing aroma precursors.

    PubMed

    Guo, W; Salmon, J M; Baumes, R; Tapiero, C; Günata, Z

    1999-07-01

    A beta-apiosidase was isolated and purified to electrophoretic homogeneity from an enzyme preparation, Klerzyme 200, through ammonium sulfate precipitation, gel filtration chromatography, ion-exchange chromatography, and HPLC on ion-exchange and size exclusion columns. The purification of the enzyme was aided by the synthesis of 4-methylumbelliferyl beta-D-apiofuranoside for the specific detection of activity on electrophoresis gels. The molecular mass estimated by SDS-PAGE was 120 kDa. The optimum activity of the beta-apiosidase was found at pH 5 and 40 degrees C. The K(m) and V(max) for p-nitrophenyl beta-D-apiofuranoside were 4.2 mM and 2460 nkat/mg of protein, respectively. The enzyme was not inhibited by glucose and ethanol. This enzyme hydrolyzed the intersugar linkages of apiofuranosylglucosides, aroma precursors from grape. PMID:10552530

  11. Aspergillus 6V4, a Strain Isolated from Manipueira, Produces High Amylases Levels by Using Wheat Bran as a Substrate

    PubMed Central

    Celestino, Jessyca dos Reis; Duarte, Ana Caroline; Silva, Cláudia Maria de Melo; Sena, Hellen Holanda; Ferreira, Maria do Perpétuo Socorro Borges Carriço; Mallmann, Neila Hiraishi; Lima, Natacha Pinheiro Costa; Tavares, Chanderlei de Castro; de Souza, Rodrigo Otávio Silva; Souza, Érica Simplício; Souza, João Vicente Braga

    2014-01-01

    The aim of this study was screening fungi strains, isolated from manipueira (a liquid subproduct obtained from the flour production of Manihot esculenta), for amylases production and investigating production of these enzymes by the strain Aspergillus 6V4. The fungi isolated from manipueira belonged to Ascomycota phylum. The strain Aspergillus 6V4 was the best amylase producer in the screening assay of starch hydrolysis in petri dishes (ASHPD) and in the assay in submerged fermentation (ASbF). The strain Aspergillus 6V4 produced high amylase levels (335 UI/L) using wheat bran infusion as the exclusive substrate and the supplementation of this substrate with peptone decreased the production of this enzyme. The moisture content of 70% was the best condition for the production of Aspergillus 6V4 amylases (385 IU/g) in solid state fermentation (SSF). PMID:24724017

  12. Fungi Isolated from Damaged Flue-cured Tobacco1

    PubMed Central

    Welty, R. E.; Lucas, G. B.

    1968-01-01

    Species of Aspergillus were the most prevalent fungi isolated from 51 samples of damaged flue-cured tobacco of the 1966 U.S. crop, comprising 57% of the total isolates. Other prevalent fungi were Penicillium (16%), Alternaria (8%), Cladosporium (4%), and Chaetomium (4%). Members of the Aspergillus glaucus group were isolated most frequently from samples with moisture contents ranging from 18 to 28%, whereas Alternaria, Cladosporium, and Penicillium were isolated consistently from samples containing 24 to 32% moisture. Aspergillus niger was prevalent in tobacco ranging in moisture content from 18 to 30%. PMID:16349805

  13. New and revisited species in Aspergillus section Nigri

    PubMed Central

    Varga, J.; Frisvad, J.C.; Kocsub, S.; Brankovics, B.; Tth, B.; Szigeti, G.; Samson, R.A.

    2011-01-01

    Four new species, Aspergillus eucalypticola, A. neoniger, A. fijiensis and A. indologenus are described and illustrated. Aspergillus eucalypticola was isolated from Eucalyptus leaf from Australia, and is related to A. tubingensis and A. costaricaensis, but could clearly be distinguished from them based on either ?-tubulin or calmodulin sequence data. Aspergillus eucalypticola produced pyranonigrin A, funalenone, aurasperone B and other naphtho-?-pyrones. Aspergillus neoniger is also a biseriate species isolated from desert sand in Namibia, and mangrove water in Venezuela, which produces aurasperone B and pyranonigrin A. Aspergillus fijiensis is a uniseriate species related to A. aculeatinus, and was isolated from soil in Fiji, and from Lactuca sativa in Indonesia. This species is able to grow at 37 C, and produces asperparalines and okaramins. Aspergillus indologenus was isolated from soil, India. This species also belongs to the uniseriate group of black aspergilli, and was found to be related to, but clearly distinguishable from A. uvarum based on ?-tubulin, calmodulin and ITS sequence data. Aspergillus indologenus produced the insecticidal compounds okaramins A, B, H, and two types of indol-alkaloids which have not been structure elucidated. Two other species, A. violaceofuscus and A. acidus, are revalidated based on molecular and extrolite data. Aspergillus violaceofuscus was found to be related to A. japonicus, and produced some of the same interesting indol-alkaloids as A. indologenus, and also produced several families of partially characterised extrolites that were also found in A. heteromorphus. Aspergillus acidus (previously known as A. foetidus var. pallidus and A. foetidus var. acidus) is also a valid species, while A. foetidus is a synonym of A. niger based on molecular and physiological data. Two other species described previously, A. coreanus and A. lacticoffeatus, were found to be colour mutants of A. acidus and A. niger, respectively. Methods which could be used to distinguish the two closely related and economically important species A. niger and A. awamori are also detailed. Although these species differ in their occurrence and several physiological means (elastase activities, abilities to utilise 2-deoxy-D-glucose as sole carbon source), our data indicate that only molecular approaches including sequence analysis of calmodulin or ?-tubulin genes, AFLP analysis, UP-PCR analysis or mtDNA RFLP analysis can be used reliably to distinguish these sibling species. Aspergillus section Nigri now includes 26 taxa. PMID:21892239

  14. New and revisited species in Aspergillus section Nigri.

    PubMed

    Varga, J; Frisvad, J C; Kocsub, S; Brankovics, B; Tth, B; Szigeti, G; Samson, R A

    2011-06-30

    Four new species, Aspergillus eucalypticola, A. neoniger, A. fijiensis and A. indologenus are described and illustrated. Aspergillus eucalypticola was isolated from Eucalyptus leaf from Australia, and is related to A. tubingensis and A. costaricaensis, but could clearly be distinguished from them based on either ?-tubulin or calmodulin sequence data. Aspergillus eucalypticola produced pyranonigrin A, funalenone, aurasperone B and other naphtho-?-pyrones. Aspergillus neoniger is also a biseriate species isolated from desert sand in Namibia, and mangrove water in Venezuela, which produces aurasperone B and pyranonigrin A. Aspergillus fijiensis is a uniseriate species related to A. aculeatinus, and was isolated from soil in Fiji, and from Lactuca sativa in Indonesia. This species is able to grow at 37 C, and produces asperparalines and okaramins. Aspergillus indologenus was isolated from soil, India. This species also belongs to the uniseriate group of black aspergilli, and was found to be related to, but clearly distinguishable from A. uvarum based on ?-tubulin, calmodulin and ITS sequence data. Aspergillus indologenus produced the insecticidal compounds okaramins A, B, H, and two types of indol-alkaloids which have not been structure elucidated. Two other species, A. violaceofuscus and A. acidus, are revalidated based on molecular and extrolite data. Aspergillus violaceofuscus was found to be related to A. japonicus, and produced some of the same interesting indol-alkaloids as A. indologenus, and also produced several families of partially characterised extrolites that were also found in A. heteromorphus. Aspergillus acidus (previously known as A. foetidus var. pallidus and A. foetidus var. acidus) is also a valid species, while A. foetidus is a synonym of A. niger based on molecular and physiological data. Two other species described previously, A. coreanus and A. lacticoffeatus, were found to be colour mutants of A. acidus and A. niger, respectively. Methods which could be used to distinguish the two closely related and economically important species A. niger and A. awamori are also detailed. Although these species differ in their occurrence and several physiological means (elastase activities, abilities to utilise 2-deoxy-D-glucose as sole carbon source), our data indicate that only molecular approaches including sequence analysis of calmodulin or ?-tubulin genes, AFLP analysis, UP-PCR analysis or mtDNA RFLP analysis can be used reliably to distinguish these sibling species. Aspergillus section Nigri now includes 26 taxa. PMID:21892239

  15. Aspergillose pulmonaire chronique nécrosante à Aspergillus niger chez un patient tabagique et ancien tuberculeux

    PubMed Central

    Yahyaoui, Ghita; Tlamçani, Imane; Benjelloun, Salma; Atwani, Mohamed; Errami, Mohamed

    2014-01-01

    Nous rapportons le cas d'une aspergillose pulmonaire chronique nécrosante chez un patient tabagique et ancien tuberculeux. Le diagnostic a été basé sur des critères radiologiques, tomodensitométriques et mycologiques. Le champignon a été isolé des crachats et de la pièce d'exérèse. En plus du traitement chirurgical, un traitement médical à base de voriconazole a été instauré. Une dose de charge de 600mg a été administrée le premier jour sous forme de deux injections intraveineuses espacées de 12 heurs, ensuite 400mg par jour répartie en deux prises matin et soir. Après 45 jours de traitement, une amélioration clinique et radiologique a été déjà observée. Lors d'aspergillose pulmonaire chronique nécrosante, un traitement antifongique de longue durée parait être nécessaire. Le Maroc est un pays bien ensoleillé, notre malade risquerait de développer une photosensibilisation. En plus l'itraconazole pouvant être une bonne alternative thérapeutique n'est pas disponible sur le marché national. PMID:25018830

  16. Antifungal Activity of Lactic Acid Bacteria Isolated from Kimchi Against Aspergillus fumigatus.

    PubMed

    Kim, Jeong-Dong

    2005-12-01

    More than 120 isolates of lactic acid bacteria obtained from Kimchi was screened for antifungal activity against Aspergillus fumigatus. Approximately 10% of the isolates showed inhibitory activity and only 4.16% (five isolates) exhibited strong activity against the indicator fungus A. fumigatus. The five isolates showed a wide rang of antifungal activity against A. flavus, Fusarium moniliforme, Penicillium commune, and Rhizopus oryzae. They were identified by 16S rDNA sequencing as Lactobacillus cruvatus, L. lactis subsp. lactis, L. casei, L. pentosus, and L. sakei. The effect of Lactobacillus on mycelial growth and fungal biomass as well as its ability to produce toxic compounds were determined. The results indicate that the three species, Lactobacillus casei, L. lactis subsp. lactis, and L. pentosus, are active against A. fumigatus. PMID:24049503

  17. Isolate-Dependent Growth, Virulence, and Cell Wall Composition in the Human Pathogen Aspergillus fumigatus

    PubMed Central

    Amarsaikhan, Nansalmaa; O’Dea, Evan M.; Tsoggerel, Angar; Owegi, Henry; Gillenwater, Jordan; Templeton, Steven P.

    2014-01-01

    The ubiquitous fungal pathogen Aspergillus fumigatus is a mediator of allergic sensitization and invasive disease in susceptible individuals. The significant genetic and phenotypic variability between and among clinical and environmental isolates are important considerations in host-pathogen studies of A. fumigatus-mediated disease. We observed decreased radial growth, rate of germination, and ability to establish colony growth in a single environmental isolate of A. fumigatus, Af5517, when compared to other clinical and environmental isolates. Af5517 also exhibited increased hyphal diameter and cell wall β-glucan and chitin content, with chitin most significantly increased. Morbidity, mortality, lung fungal burden, and tissue pathology were decreased in neutropenic Af5517-infected mice when compared to the clinical isolate Af293. Our results support previous findings that suggest a correlation between in vitro growth rates and in vivo virulence, and we propose that changes in cell wall composition may contribute to this phenotype. PMID:24945802

  18. Antifungal Activity of Lactic Acid Bacteria Isolated from Kimchi Against Aspergillus fumigatus

    PubMed Central

    2005-01-01

    More than 120 isolates of lactic acid bacteria obtained from Kimchi was screened for antifungal activity against Aspergillus fumigatus. Approximately 10% of the isolates showed inhibitory activity and only 4.16% (five isolates) exhibited strong activity against the indicator fungus A. fumigatus. The five isolates showed a wide rang of antifungal activity against A. flavus, Fusarium moniliforme, Penicillium commune, and Rhizopus oryzae. They were identified by 16S rDNA sequencing as Lactobacillus cruvatus, L. lactis subsp. lactis, L. casei, L. pentosus, and L. sakei. The effect of Lactobacillus on mycelial growth and fungal biomass as well as its ability to produce toxic compounds were determined. The results indicate that the three species, Lactobacillus casei, L. lactis subsp. lactis, and L. pentosus, are active against A. fumigatus. PMID:24049503

  19. Biodiversity of Aspergillus section Nigri populations in Argentinian vineyards and ochratoxin A contamination.

    PubMed

    Chiotta, Mara L; Ponsone, Mara L; Sosa, Dbora M; Combina, Mariana; Chulze, Sofa N

    2013-12-01

    Aspergillus section Nigri are described as the main source of ochratoxin A (OTA) contamination in grapes and wine worldwide. The knowledge of the factors affecting grape contamination by species included in this section and OTA production is essential to be able to reduce their presence, not only to improve wine quality, but also to maintain their safety. Therefore, the aims of this study were to determine the incidence of Aspergillus section Nigri species harvested in different grape-growing regions from Argentina, their ability to produce OTA, to correlate with meteorological conditions and geographical coordinates with their prevalence and to evaluate the OTA natural occurrence in grapes and wines. The morphological identification showed that Aspergillus niger aggregate species were the most prevalent ones, followed by Aspergillus carbonarius and Aspergillus uniseriate. These populations were confirmed through using AFLP markers and sequencing and, Aspergillus tubingensis was separated from A. niger aggregate. Climatic factors, altitude, longitude and latitude have influenced on the distribution of species included in the section. A. carbonarius and A. niger were OTA producers but differed in their OTA producing ability. Temperature was the factor which influenced the most over the highest incidence of A. carbonarius in La Rioja and San Juan regions. The trellis system in vineyards and drip irrigation also influenced the species isolation. The OTA levels detected in grapes and wines were low, but grape variety was more important in susceptibility to fungal infection and OTA levels. PMID:24010597

  20. Isolation and Identification of a Strain of Aspergillus Tubingensis With Deoxynivalenol Biotransformation Capability

    PubMed Central

    He, Chenghua; Fan, Yanhong; Liu, Guofang; Zhang, Haibin

    2008-01-01

    Deoxynivalenol (DON) is one of the most common contaminants of various foodstuffs. A biotransformation system was used in order to lessen the toxicity of DON. A strain of Aspergillus (NJA-1) was isolated from soil and cultured in an inorganic salt medium containing DON. Bt2a/Bt2b primers were used to amplify the ?-tubulin gene of NJA-1. Sequence analysis the PCR product and morphology observation indicated that NJA-1 belonged to Aspergillus tubingensis (aerobic fungi). The DNA sequence information of the PCR product was deposited in GenBank (accession number DQ9025790). The DNA sequence had 99% similarity to the Aspergillus tubingensis accession number AY820009. An unknown compound in NJA-1 showed the ability to convert DON into another product. The molecular weight of the bioconversion product was 18.1 D (H2O) larger than that of DON. The analysis showed that DON could be hydrolyzed by NJA-1. The mean DON biotransformation rate was 94.4% after two weeks of cultivation. The finding presents a new method for DON biotransformation. PMID:19330081

  1. Diversity of Aspergillus oryzae genotypes (RFLP) isolated from traditional soy sauce production within Malaysia and Southeast Asia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DNA fingerprinting was performed on 64 strains of Aspergillus oryzae and one strain of A. sojae isolated from soysauce factories within Malaysia and Southeast Asia that use primitive traditional methods in producing 'tamari type' Cantonese soy sauce. PstI digests of total genomic DNA from each isol...

  2. Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus.

    PubMed

    Fountain, Jake C; Scully, Brian T; Chen, Zhi-Yuan; Gold, Scott E; Glenn, Anthony E; Abbas, Hamed K; Lee, R Dewey; Kemerait, Robert C; Guo, Baozhu

    2015-08-01

    Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, the objectives of this study were to examine the effects of hydrogen peroxide (H2O2)-induced oxidative stress on the growth of different toxigenic (+) and atoxigenic (-) isolates of Aspergillus flavus and to test whether aflatoxin production affects the H2O2 concentrations that the isolates could survive. Ten isolates were tested: NRRL3357 (+), A9 (+), AF13 (+), Tox4 (+), A1 (-), K49 (-), K54A (-), AF36 (-), and Aflaguard (-); and one A. parasiticus isolate, NRRL2999 (+). These isolates were cultured under a H2O2 gradient ranging from 0 to 50 mM in two different media, aflatoxin-conducive yeast extract-sucrose (YES) and non-conducive yeast extract-peptone (YEP). Fungal growth was inhibited at a high H2O2 concentration, but specific isolates grew well at different H2O2 concentrations. Generally the toxigenic isolates tolerated higher concentrations than did atoxigenic isolates. Increasing H2O2 concentrations in the media resulted in elevated aflatoxin production in toxigenic isolates. In YEP media, the higher concentration of peptone (15%) partially inactivated the H2O2 in the media. In the 1% peptone media, YEP did not affect the H2O2 concentrations that the isolates could survive in comparison with YES media, without aflatoxin production. It is interesting to note that the commercial biocontrol isolates, AF36 (-), and Aflaguard (-), survived at higher levels of stress than other atoxigenic isolates, suggesting that this testing method could potentially be of use in the selection of biocontrol isolates. Further studies will be needed to investigate the mechanisms behind the variability among isolates with regard to their degree of oxidative stress tolerance and the role of aflatoxin production. PMID:26251922

  3. [Comparative morphological, ecological, and molecular studies of Aspergillus versicolor (Vuill.) Tiraboschi strains isolated from different ecotopes].

    PubMed

    Fomicheva, G M; Vasilenko, O V; Marfenina, O E

    2006-01-01

    Cultural, morphological, ecological, and trophic properties (growth at different temperatures and on various organic substrates), as well as molecular and genetic peculiarities of Aspergillus versicolor (Vuill) Tiraboschi strains of different origins, were determined. The strains were isolated from different ecotopes (upper horizons of modern soils of several geographic regions, ancient soils and peat, and permafrost). No essential distinctions in cultural and morphological properties were revealed between the strains. Strains obtained from peat of the Aleutian Islands were characterized by the highest radial rates of colony growth. Some variations in the ITS loci of rDNA were observed in strains isolated from different ecotopes; the distinctions were most pronounced (1.7%) in the strain isolated from 100 000-year-old permafrost. PMID:16758871

  4. Isolation of Aspergillus spp. from the respiratory tract in critically ill patients: risk factors, clinical presentation and outcome

    PubMed Central

    Garnacho-Montero, Jos; Amaya-Villar, Rosario; Ortiz-Leyba, Carlos; Len, Cristbal; lvarez-Lerma, Francisco; Nolla-Salas, Juan; Iruretagoyena, Jos R; Barcenilla, Fernando

    2005-01-01

    Introduction Our aims were to assess risk factors, clinical features, management and outcomes in critically ill patients in whom Aspergillus spp. were isolated from respiratory secretions, using a database from a study designed to assess fungal infections. Methods A multicentre prospective study was conducted over a 9-month period in 73 intensive care units (ICUs) and included patients with an ICU stay longer than 7 days. Tracheal aspirate and urine samples, and oropharyngeal and gastric swabs were collected and cultured each week. On admission to the ICU and at the initiation of antifungal therapy, the severity of illness was evaluated using the Acute Physiology and Chronic Health Evaluation II score. Retrospectively, isolation of Aspergillus spp. was considered to reflect colonization if the patient did not fulfil criteria for pneumonia, and infection if the patient met criteria for pulmonary infection and if the clinician in charge considered the isolation to be clinically valuable. Risk factors, antifungal use and duration of therapy were noted. Results Out of a total of 1756 patients, Aspergillus spp. were recovered in 36. Treatment with steroids (odds ratio = 4.5) and chronic obstructive pulmonary disease (odds ratio = 2.9) were significantly associated with Aspergillus spp. isolation in multivariate analysis. In 14 patients isolation of Aspergillus spp. was interpreted as colonization, in 20 it was interpreted as invasive aspergillosis, and two cases were not classified. The mortality rates were 50% in the colonization group and 80% in the invasive infection group. Autopsy was performed in five patients with clinically suspected infection and confirmed the diagnosis in all of these cases. Conclusion In critically ill patients, treatment should be considered if features of pulmonary infection are present and Aspergillus spp. are isolated from respiratory secretions. PMID:15987390

  5. In Vitro Activity of ASP2397 against Aspergillus Isolates with or without Acquired Azole Resistance Mechanisms.

    PubMed

    Arendrup, Maiken Cavling; Jensen, Rasmus Hare; Cuenca-Estrella, Manuel

    2015-01-01

    ASP2397 is a new compound with a novel and as-yet-unknown target different from that of licensed antifungal agents. It has activity against Aspergillus and Candida glabrata. We compared its in vitro activity against wild-type and azole-resistant A. fumigatus and A. terreus isolates with that of amphotericin B, itraconazole, posaconazole, and voriconazole. Thirty-four isolates, including 4 wild-type A. fumigatus isolates, 24 A. fumigatus isolates with alterations in CYP51A TR/L98H (5 isolates), M220 (9 isolates), G54 (9 isolates), and HapE (1 isolate), and A. terreus isolates (2 wild-type isolates and 1 isolate with an M217I CYP51A alteration), were analyzed. EUCAST E.Def 9.2 and CLSI M38-A2 MIC susceptibility testing was performed. ASP2397 MIC50 values (in milligrams per liter, with MIC ranges in parentheses) determined by EUCAST and CLSI were 0.5 (0.25 to 1) and 0.25 (0.06 to 0.25) against A. fumigatus CYP51A wild-type isolates and were similarly 0.5 (0.125 to >4) and 0.125 (0.06 to >4) against azole-resistant A. fumigatus isolates, respectively. These values were comparable to those for amphotericin B, which were 0.25 (0.125 to 0.5) and 0.25 (0.125 to 0.25) against wild-type isolates and 0.25 (0.125 to 1) and 0.25 (0.125 to 1) against isolates with azole resistance mechanisms, respectively. In contrast, MICs for the azole compounds were elevated and highest for itraconazole: >4 (1 to >4) and 4 (0.5 to >4) against isolates with azole resistance mechanisms compared to 0.125 (0.125 to 0.25) and 0.125 (0.06 to 0.25) against wild-type isolates, respectively. ASP2397 was active against A. terreus CYP51A wild-type isolates (MIC 0.5 to 1), whereas MICs of both azole and ASP2397 were elevated for the mutant isolate. ASP2397 displayed in vitro activity against A. fumigatus and A. terreus isolates which was independent of the presence or absence of azole target gene resistance mutations in A. fumigatus. The findings are promising at a time when azole-resistant A. fumigatus is emerging globally. PMID:26552973

  6. Sequence determination of a quadripartite dsRNA virus isolated from Aspergillus foetidus.

    PubMed

    Kozlakidis, Zisis; Herrero, Noemi; Ozkan, Selin; Kanhayuwa, Lakkhana; Jamal, Atif; Bhatti, Muhammad F; Coutts, Robert H A

    2013-01-01

    Virus infection of Aspergillus foetidus was documented over 40 years ago and was one of the first mycovirus infections described in a filamentous fungus. The virus, named Aspergillus foetidus virus (AfV), contains at least two types of icosahedral particles, called AfV-fast (-F) and AfV-slow (-S) virions, based on their relative electrophoretic mobilities. Here, we report the complete nucleotide sequence of the AfV-F genome isolated from virions purified from the prototype isolate of the fungus. The AfV-F double-stranded (ds) RNA genome is tetra-segmented, and the plus strands of each of the four segments, but not the minus strands, are polyadenylated. The organisation and sequences of the four AfV-F dsRNAs are similar to those described for Alternaria alternata virus 1, which we propose is a member of an emerging mycovirus genus ("Alternavirus") and family ("Alternaviridae"), which also includes AfV-F. PMID:22760661

  7. Culture Conditions and Characterizations of a New Phytase-Producing Fungal Isolate, Aspergillus sp. L117

    PubMed Central

    Lee, Dae-Hee; Choi, Sun-Uk

    2005-01-01

    A novel fungal strain Aspergillus sp. L117 that produced acid-stable and thermostable phytase was isolated on basis of the clearing zone on PSM plate and the ability of Na-phytate hydrolysis. The phytase of isolate showed a 3-fold higher activity than that of A. ficuun NRRL3135. The Aspergillus sp. L117 produced maximal level of phytase at initial pH of 5.0 and 30℃. The optimal pH and temperature for phytase activity were 5.5 and 50℃, respectively. The phytase showed totally stable activity after 20 min of exposure between 30 and 90℃, and even at 100℃. The highest level of residual phytase activity was obtained at pH 5.5, and still retained the stability at the broadest pH ranges (2.0 to 7.0) of all the aforementioned phytases. Storage stability of phytase was preserved over 96% of initial activities for 60 days at 4, -20, and -70℃ and to retain even 70% of the initial activity at room temperature. PMID:24049505

  8. Analysis of genetic and aflatoxin diversity among Aspergillus flavus isolates collected from sorghum seeds.

    PubMed

    Divakara, S T; Aiyaz, M; Moore, G G; Venkataramana, M; Hariprasad, P; Nayaka, S Chandra; Niranjana, S R

    2015-11-01

    Thirty-four Aspergillus flavus isolates were recovered from sorghum seeds sampled across five states in India. Our study included (1) species confirmation through PCR assay, (2) quantification of total aflatoxin concentrations by the indirect competitive-ELISA (ic-ELISA) method, and (3) analysis of molecular diversity among the A. flavus isolates using ?-tubulin, ITS, and ISSR markers. Among the isolates studied, 28 were found to be positive for the production of aflatoxins. ITS and ?-tubulin phylogenetic analysis segregated the A. flavus sample population into two major groups or clades with little to no subdivision based on geography. In contrast, ISSR analysis also separated the A. flavus isolates into two main clusters, showing a distance of 0.0-0.5, with one cluster exhibiting a high level of diversity though no geographic or chemotype subdivision could be observed. The majority of sampled A. flavus isolates were highly toxigenic, and also highly diversified in terms of toxin-producing potential in-vitro. Genetic diversity among the sorghum isolates of A. flavus further warrants the development of appropriate farming management practices as well as improved aflatoxin detection measures in India. PMID:26102515

  9. Genetic Variability of Aspergillus flavus Isolates from a Mississippi Corn Field

    PubMed Central

    Solorzano, Cesar D.; Abbas, Hamed K.; Zablotowicz, Robert M.; Chang, Perng-Kuang; Jones, Walker A.

    2014-01-01

    A nontoxigenic Aspergillus flavus strain, K49, is currently being tested as a biological control agent in corn fields in the Mississippi Delta. However, little is known about the overall genetic diversity of A. flavus from year to year in corn fields and specifically in Mississippi. Our objective was to assess the genetic variability of A. flavus isolates from different seasons, inoculum sources, and years, from a no-till corn field. Of the 175 A. flavus isolates examined, 74 and 97 had the typical norB-cypA type I (1.5?kb) and type II (1.0?kb) deletion patterns, respectively. Variability in the sequence of the omtA gene of the majority of the field isolates (n = 118) was compared to strain K49. High levels of haplotypic diversity (24 omtA haplotypes; Hd = 0.61 0.04) were found. Among the 24 haplotypes, two were predominant, H1 (n = 71), which consists of mostly toxigenic isolates, and H49 (n = 18), which consists of mostly atoxigenic isolates including K49. Toxigenic isolates were prevalent (60%) in this natural population. Nonetheless, about 15% of the population likely shared the same ancestral origin with K49. This study provides valuable information on the diversity of A. flavus. This knowledge can be further used to develop additional biological control strains. PMID:25478591

  10. Identification of fungi of the genus Aspergillus section nigri using polyphasic taxonomy

    PubMed Central

    Silva, Daiani M.; Batista, Luís R.; Rezende, Elisângela F.; Fungaro, Maria Helena P.; Sartori, Daniele; Alves, Eduardo

    2011-01-01

    In spite of the taxonomy of the Aspergillus species of the Nigri Section being regarded as troublesome, a number of methods have been proposed to aid in the classification of this Section. This work aimed to distinguish Aspergillus species of the Nigri Section from foods, grains and caves on the basis in Polyphasic Taxonomy by utilizing morphologic and physiologic characters, and sequencing of ß-tubulin and calmodulin genes. The morphologic identification proved useful for some species, such as A. carbonarius and Aspergillus sp UFLA DCA 01, despite not having been totally effective in elucidating species related to A. niger. The isolation of the species of the Nigri Section on Creatine Sucrose Agar (CREA) enabled to distinguish the Aspergillus sp species, which was characterized by the lack of sporulation and by the production of sclerotia. Scanning Electron microscopy (SEM) allowed distinguishing the species into two distinct groups. The production of Ochratoxin A (OTA) was only found in the A. carbonarius and A. niger species. The sequencing of β-tubulin gene was efficient in differing most of the Aspergillus species from the Nigri Section with the exception of Aspergillus UFLA DCA 01, which could not be distinguished from A. costaricaensis. This species is morphologically similar to A. costaricaencis for its low sporulation capacity and high sclerotia production, but it differs morphologically from A. costaricaensis for its conidial ornamentation and size of vesicles. Equally, based on partial calmodulin gene sequence data Aspergillus UFLA DCA 01 differs from A. costaricaensis. PMID:24031691

  11. Toxigenic potentiality of Aspergillus flavus and Aspergillus parasiticus strains isolated from black pepper assessed by an LC-MS/MS based multi-mycotoxin method.

    PubMed

    Yogendrarajah, Pratheeba; Devlieghere, Frank; Njumbe Ediage, Emmanuel; Jacxsens, Liesbeth; De Meulenaer, Bruno; De Saeger, Sarah

    2015-12-01

    A liquid chromatography triple quadrupole tandem mass spectrometry method was developed and validated to determine mycotoxins, produced by fungal isolates grown on malt extract agar (MEA). All twenty metabolites produced by different fungal species were extracted using acetonitrile/1% formic acid. The developed method was applied to assess the toxigenic potentiality of Aspergillus flavus (n=11) and Aspergillus parasiticus (n=6) strains isolated from black peppers (Piper nigrum L.) following their growth at 22, 30 and 37C. Highest mean radial colony growth rates were observed at 30C for A.flavus (5.210.68mm/day) and A.parasiticus (4.970.33mm/day). All of the A.flavus isolates produced aflatoxin B1 and O-methyl sterigmatocystin (OMST) while 91% produced aflatoxin B2 (AFB2) and 82% of them produced sterigmatocystin (STERIG) at 30C. Except one, all the A.parasiticus isolates produced all the four aflatoxins, STERIG and OMST at 30C. Remarkably high AFB1 was produced by some A.flavus isolates at 22C (max 16-40mg/kg). Production of mycotoxins followed a different trend than that of growth rate of both species. Notable correlations were found between different secondary metabolites of both species; R(2) 0.87 between AFB1 and AFB2 production. Occurrence of OMST could be used as a predictor for AFB1 production. PMID:26338134

  12. Nonaflatoxigenic Aspergillus flavus TX9-8 Competitively Prevents Aflatoxin Production by A. flavus Isolates of Large and Small Sclerotial Morphotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Toxigenic Aspergillus flavus is the main etiological agent for aflatoxin contamination of crops. Using nonaflatoxigenic A. flavus isolates to competitively exclude toxigenic A. flavus isolates in agricultural fields has become an adopted approach to reduce aflatoxin contamination. We determined th...

  13. Multilocus variable-number tandem-repeat analysis of clinical isolates of Aspergillus flavus from Iran reveals the first cases of Aspergillus minisclerotigenes associated with human infection

    PubMed Central

    2014-01-01

    Background Aspergillus flavus is intensively studied for its role in infecting crop plants and contaminating produce with aflatoxin, but its role as a human pathogen is less well understood. In parts of the Middle East and India, A. flavus surpasses A. fumigatus as a cause of invasive aspergillosis and is a significant cause of cutaneous, sinus, nasal and nail infections. Methods A collection of 45 clinical and 10 environmental A. flavus isolates from Iran were analysed using Variable-Number Tandem-Repeat (VNTR) markers with MICROSAT and goeBURST to determine their genetic diversity and their relatedness to clinical and environmental A. flavus isolates from Australia. Phylogeny was assessed using partial β-tubulin and calmodulin gene sequencing, and mating type was determined by PCR. Antifungal susceptibility testing was performed on selected isolates using a reference microbroth dilution method. Results There was considerable diversity in the A. flavus collection, with no segregation on goeBURST networks according to source or geographic location. Three Iranian isolates, two from sinus infections and one from a paranasal infection grouped with Aspergillus minisclerotigenes, and all produced B and G aflatoxin. Phylogenic analysis using partial β-tubulin and calmodulin sequencing confirmed two of these as A. minisclerotigenes, while the third could not be differentiated from A. flavus and related species within Aspergillus section flavi. Based on epidemiological cut-off values, the A. minisclerotigens and A. flavus isolates tested were susceptible to commonly used antifungal drugs. Conclusions This is the first report of human infection due to A. minisclerotigenes, and it raises the possiblity that other species within Aspergillus section flavi may also cause clinical disease. Clinical isolates of A. flavus from Iran are not distinct from Australian isolates, indicating local environmental, climatic or host features, rather than fungal features, govern the high incidence of A. flavus infection in this region. The results of this study have important implications for biological control strategies that aim to reduce aflatoxin by the introduction of non-toxigenic strains, as potentially any strain of A. flavus, and closely related species like A. minisclerotigenes, might be capable of human infection. PMID:24986045

  14. Radiosensitivity of toxigenic Aspergillus isolated from spices and destruction of aflatoxins by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Kume, Tamikazu; Ito, Hitoshi; Soedarman, Harsono; Ishigaki, Isao

    Radiosensitivities of Aspergillus flavus var columnaris isolated from spices were investigated. The D10 values and induction doses were 267-293 Gy and 75-165 Gy in wet conditions, respectively. In dry conditions, the survival curves were exponential and D10 values were 538-600 Gy. The survival curves of standard strain of A. parasiticus IFO 30179 were similar both in wet and dry conditions. The necessary dose of 8 kGy for the destruction of these toxigenic Aspergillus was calculated from these values. Two of 11 strains of A. flavus var columnaris produced aflatoxins and the content of B 1 was especially high. In the study of irradiation effect on aflatoxins produced on polished rice, aflatoxins G 1 and B 1 were more radiosensitive than G 2 and B 2. However, these aflatoxins were very stable to radiation and the dose required for destruction was found to be more than 500 kGy. It is therfore concluded that the decontamination of molds by irradiation is necessary prior to their production of aflatoxins.

  15. Gliotoxin Isolated from Marine Fungus Aspergillus sp. Induces Apoptosis of Human Cervical Cancer and Chondrosarcoma Cells

    PubMed Central

    Nguyen, Van-Tinh; Lee, Jung Suck; Qian, Zhong-Ji; Li, Yong-Xin; Kim, Kil-Nam; Heo, Soo-Jin; Jeon, You-Jin; Park, Won Sun; Choi, Il-Whan; Je, Jae-Young; Jung, Won-Kyo

    2013-01-01

    Gliotoxin, a secondary metabolite produced by marine fungus Aspergillus sp., possesses various biological activities including anticancer activity. However, the mechanism underlying gliotoxin-induced cytotoxicity on human cervical cancer (Hela) and human chondrosarcoma (SW1353) cells remains unclear. In this study, we focused on the effect of gliotoxin induction on apoptosis, the activating expressions of caspase family enzymes in the cells. Apoptotic cell levels were measured through DAPI and Annexin V/Propidium Iodide (PI) double staining analysis. The apoptotic protein expression of Bcl-2 and caspase family was detected by Western blot in Hela and SW1353 cells. Our results showed that gliotoxin treatment inhibited cell proliferation and induced significant morphological changes. Gliotoxin induced apoptosis was further confirmed by DNA fragmentation, chromatin condensation and disrupted mitochondrial membrane potential. Gliotoxin-induced activation of caspase-3, caspase-8 and caspase-9, down-regulation of Bcl-2, up-regulation of Bax and cytochromec (cyt c) release showed evidence for the gliotoxin activity on apoptosis. These findings suggest that gliotoxin isolated from marine fungus Aspergillus sp. induced apoptosis in Hela and SW1353 cells via the mitochondrial pathway followed by downstream events leading to apoptotic mode of cell death. PMID:24368570

  16. A single mutation in the hepta-peptide active site of Aspergillus niger PhyA phytase leads to myriad of biochemical changes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The active site motif of proteins belonging to ‘Histidine Acid Phosphatase’ (HAP) contains a hepta-peptide region, RHGXRXP. A close comparison among fungal and yeast HAPs has revealed the fourth residue of the hepta-peptide to be E instead of A, which is the case with A. niger phyA phytase. However,...

  17. Effects of Hydrogen Peroxide on Different Toxigenic and Atoxigenic Isolates of Aspergillus flavus

    PubMed Central

    Fountain, Jake C.; Scully, Brian T.; Chen, Zhi-Yuan; Gold, Scott E.; Glenn, Anthony E.; Abbas, Hamed K.; Lee, R. Dewey; Kemerait, Robert C.; Guo, Baozhu

    2015-01-01

    Drought stress in the field has been shown to exacerbate aflatoxin contamination of maize and peanut. Drought and heat stress also produce reactive oxygen species (ROS) in plant tissues. Given the potential correlation between ROS and exacerbated aflatoxin production under drought and heat stress, the objectives of this study were to examine the effects of hydrogen peroxide (H2O2)-induced oxidative stress on the growth of different toxigenic (+) and atoxigenic (−) isolates of Aspergillus flavus and to test whether aflatoxin production affects the H2O2 concentrations that the isolates could survive. Ten isolates were tested: NRRL3357 (+), A9 (+), AF13 (+), Tox4 (+), A1 (−), K49 (−), K54A (−), AF36 (−), and Aflaguard (−); and one A. parasiticus isolate, NRRL2999 (+). These isolates were cultured under a H2O2 gradient ranging from 0 to 50 mM in two different media, aflatoxin-conducive yeast extract-sucrose (YES) and non-conducive yeast extract-peptone (YEP). Fungal growth was inhibited at a high H2O2 concentration, but specific isolates grew well at different H2O2 concentrations. Generally the toxigenic isolates tolerated higher concentrations than did atoxigenic isolates. Increasing H2O2 concentrations in the media resulted in elevated aflatoxin production in toxigenic isolates. In YEP media, the higher concentration of peptone (15%) partially inactivated the H2O2 in the media. In the 1% peptone media, YEP did not affect the H2O2 concentrations that the isolates could survive in comparison with YES media, without aflatoxin production. It is interesting to note that the commercial biocontrol isolates, AF36 (−), and Aflaguard (−), survived at higher levels of stress than other atoxigenic isolates, suggesting that this testing method could potentially be of use in the selection of biocontrol isolates. Further studies will be needed to investigate the mechanisms behind the variability among isolates with regard to their degree of oxidative stress tolerance and the role of aflatoxin production. PMID:26251922

  18. Bioactive anthraquinones from endophytic fungus Aspergillus versicolor isolated from red sea algae.

    PubMed

    Hawas, Usama W; El-Beih, Ahmed Atef; El-Halawany, Ali M

    2012-10-01

    The marine fungus Aspergillus versicolor was isolated from the inner tissue of the Red Sea green alga Halimeda opuntia. The fungus was identified by its morphology and 18s rDNA. Cultivation of this fungal strain led to a new metabolite named isorhodoptilometrin-1-methyl ether (1) along with the known compounds emodin (2), 1-methyl emodin (3), evariquinone (4), 7-hydroxyemodin 6,8-methyl ether (5), siderin (6), arugosin C (7), and variculanol (8). The structures were elucidated on the basis of NMR spectroscopic analysis and mass spectrometry. The biological properties of ethyl acetate extract and compounds 1-3 and 6-8 were explored for antimicrobial activity, anti-cancer activity and inhibition of Hepatitis C virus (HCV) protease. PMID:23139125

  19. Morphological and toxigenic variability in the Aspergillus flavus isolates from peanut (Arachis hypogaea L.) production system in Gujarat (India).

    PubMed

    Singh, Diwakar; Thankappan, Radhakrishnan; Kumar, Vinod; Bagwan, Naimoddin B; Basu, Mukti S; Dobaria, Jentilal R; Mishra, Gyan P; Chanda, Sumitra

    2015-03-01

    Morphological and toxigenic variability in 187 Aspergillus flavus isolates, collected from a major Indian peanut production system, from 10 districts of Gujarat was studied. On the basis of colony characteristics, the isolates were grouped as group A (83%), B (11%) and G (6%). Of all the isolates, 21%, 47% and 32% were found to be fast-growing, moderately-fast and slow-growing respectively, and nosclerotia and sclerotia production was recorded in 32.1% and 67% isolates respectively. Large, medium and small number of sclerotia production was observed in 55, 38 and 34 isolates respectively. Toxigenic potential based on ammonia vapour test was not found reliable, while ELISA test identified 68.5%, 18.7% and 12.8% isolates as atoxigenic, moderately-toxigenic and highly-toxigenic, respectively. On clustering, the isolates were grouped into 15 distinct clusters, 'A' group of isolates was grouped distinctly in different clusters, while 'B' and 'G' groups of isolates were clustered together. No association was observed between morphological-diversity and toxigenic potential of the isolates. From the present investigation, most virulent isolates were pooled to form a consortium for sick-plot screening of germplasm, against Aspergillus flavus. In future, atoxigenic isolates may be evaluated for their potential to be used as bio-control agent against toxigenicisolates. PMID:25895268

  20. Characterization of Expressed Sequence Tag-Derived Simple Sequence Repeat Markers for Aspergillus flavus: Emphasis on Variability of Isolates from the Southern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple Sequence Repeat (SSR) markers were developed from Aspergillus flavus expressed sequence tag (EST) database to conduct an analysis of genetic relationships of Aspergillus isolates from numerous host species and geographical regions, but primarily from the United States. Twenty-nine primers wer...

  1. Isolation, structure elucidation, and biomimetic total synthesis of versicolamide B and the isolation of antipodal (-)-stephacidin A and (+)-notoamide B from Aspergillus versicolor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new prenylated indole alkaloid, versicolamide B, was isolated from cultures of Aspergillus versicolor NRRL 35600. The structure was assigned by 2D NMR data, and confirmed by a biomimetic total synthesis. Versicolamide B is the first member of the paraherquamide-stephacidin family of alkaloids fo...

  2. Data set for the mass spectrometry based exoproteome analysis of Aspergillus flavus isolates

    PubMed Central

    Muthu Selvam, Ramu; Nithya, Rathnavel; Narmatha Devi, Palraj; Bhuvana Shree, R.S.; Valar Nila, Murugesan; Demonte, Naveen Luke; Thangavel, Chitra; Jeya Maheshwari, Jayapal; Lalitha, Prajna; Venkatesh Prajna, Namperumalsamy; Dharmalingam, Kuppamuthu

    2014-01-01

    Aspergillus flavus is one of the predominant causative organisms of mycotic keratitis in tropical parts of the world. Extracellular proteins are the earliest proteins that come in contact with the host and have a role in the infection process. Exoproteins of A. flavus isolated from infected cornea, sputum and a saprophyte were pooled and identified using high resolution mass spectrometry in order to get the total exoproteome from cultures isolated from different sources. A total of 637 proteins was identified from the pooled A. flavus exoproteome. Analysis based on GO annotations of the 637 identified proteins revealed that hydrolases form the predominant class of proteins in the exoproteome. Interestingly, a greater proportion of the exoproteins seem to be secreted through the non-classical pathways. This data represent the first in-depth analysis of the representative A. flavus exoproteome of a large set of isolates from distinct sources. This data have been deposited to the ProteomeXchange with identifier PXD001296. PMID:26217704

  3. Occurrence of Toxigenic Aspergillus versicolor Isolates and Sterigmatocystin in Carpet Dust from Damp Indoor Environments

    PubMed Central

    Engelhart, Steffen; Loock, Annette; Skutlarek, Dirk; Sagunski, Helmut; Lommel, Annette; Frber, Harald; Exner, Martin

    2002-01-01

    Over the past decade, there has been growing concern regarding the role of toxigenic fungi in damp indoor environments; however, there is still a lack of field investigations on exposure to mycotoxins. The goal of our pilot study was to quantify the proportion of toxigenic Aspergillus versicolor isolates in native carpet dust from damp dwellings with mold problems and to determine whether sterigmatocystin can be detected in this matrix. Carpet dust samples (n = 11) contained from <2.5 101 to 3.6 105 (median, 3.1 104) A. versicolor CFU/g of dust, and the median proportion of A. versicolor from total culturable fungi was 18%. Based on thin-layer chromatography detection of sterigmatocystin, 49 of 50 A. versicolor isolates (98%) were found to be toxigenic in vitro. By using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry, sterigmatocystin could be detected in low concentrations (2 to 4 ng/g of dust) in 2 of 11 native carpet dust samples. From this preliminary study, we conclude that most strains of A. versicolor isolated from carpet dust are able to produce sterigmatocystin in vitro and that sterigmatocystin may occasionally occur in carpet dust from damp indoor environments. Further research and systematic field investigation are needed to confirm our results and to provide an understanding of the health implications of mycotoxins in indoor environments. PMID:12147486

  4. The effectiveness of arbuscular-mycorrhizal fungi and Aspergillus niger or Phanerochaete chrysosporium treated organic amendments from olive residues upon plant growth in a semi-arid degraded soil.

    PubMed

    Medina, A; Roldn, A; Azcn, R

    2010-12-01

    Arbuscular mycorrhizal (AM) fungi and a residue from dry olive cake (DOC) supplemented with rock phosphate (RP) and treated with either Aspergillus niger (DOC-A) or Phanerochaete chrysosporium (DOC-P), were assayed in a natural, semi-arid soil using Trifolium repens or Dorycnium pentaphyllum plants. The effects of the AM fungi and/or DOC-A were compared with P-fertilisation (P) over eleven successive harvests to evaluate the persistence of the effectiveness of the treatments. The biomass of dually-treated plants after four successive harvests was greater than that obtained for non-treated plants or those receiving the AM inoculum or DOC-A treatments after eleven yields. The AM inoculation was critical for obtaining plant growth benefit from the application of fermented DOC-A residue. The abilities of the treatments to prevent plant drought stress were also assayed. Drought-alleviating effects were evaluated in terms of plant growth, proline and total sugars concentration under alternative drought and re-watering conditions (8th and 9th harvests). The concentrations of both compounds in plant biomass increased under drought when DOC-A amendment and AM inoculation were employed together: they reinforced the plant drought-avoidance capabilities and anti-oxidative defence. Water stress was less compensated in P-fertilised than in DOC-A-treated plants. DOC-P increased D. pentaphyllum biomass, shoot P content, nodule number and AM colonisation, indicating the greater DOC-transforming ability of P. chrysosporium compared to A. niger. The lack of AM colonisation and nodulation in this soil was compensated by the application of DOC-P, particularly with AM inoculum. The management of natural resources (organic amendments and soil microorganisms) represents an important strategy that assured the growth, nutrition and plant establishment in arid, degraded soils, preventing the damage that arises from limited water and nutrient supply. PMID:20705386

  5. Isolation and identification of nematode-antagonistic compounds from the fungus Aspergillus candidus.

    PubMed

    Shemshura, Olga N; Bekmakhanova, Nadiya E; Mazunina, Mariya N; Meyer, Susan L F; Rice, Clifford P; Masler, Edward P

    2016-03-01

    Culture medium from an isolate of the fungus Aspergillus candidus was extracted, fractionated and examined to discover compounds antagonistic to plant-parasitic nematodes that are important pathogens of agricultural crops. Column, thin layer and preparative chromatographies and spectral and elemental analyses, were used to isolate and identify two major constituents of an active fraction (Fraction F) obtained from the medium. Compound 1 was identified as 2-hydroxypropane-1, 2, 3-tricarboxylic acid (citric acid). Compound 2 was identified as 3-hydroxy-5-methoxy-3-(methoxycarbonyl)-5-oxopentanoic acid, an isomer of 1, 2-dimethyl citrate. Compound 1 and a citric acid standard, each tested at 50 mg mL(-1) in water, decreased hatch from eggs of the plant-parasitic nematode Meloidogyne incognita by more than 94%, and completely immobilized second-stage juveniles after 4-6 days exposure. Fraction F and Compounds 1 and 2 decreased the mobility of adults of the plant-parasitic nematode Ditylenchus destructor in vitro. Fraction F (25 mg mL(-1)) inhibited mobility >99% at 72 hrs. Compounds 1 and 2 (50 mg mL(-1)) each inhibited mobility more than 25% at 24 hr and more than 50% at 72 hr. This is the first assignment of nematode-antagonistic properties to specifically identified A. candidus metabolites. PMID:26850440

  6. A novel pathway for nicotine degradation by Aspergillus oryzae 112822 isolated from tobacco leaves.

    PubMed

    Meng, Xiang Jing; Lu, Li Li; Gu, Guo Feng; Xiao, Min

    2010-09-01

    An efficient nicotine-degrading fungus was isolated from tobacco leaves and identified as Aspergillus oryzae 112822 based on morphological characteristics and sequence analysis of 18S rDNA, 5.8S rDNA and the internal transcribed spacer (5.8S-ITS region). When the strain was cultured in a medium with tobacco leaf extract for 40 h, the maximum amount of cell growth was 3.6 g l(-1) and nicotine degradation was 2.19 g l(-1). The intermediates of nicotine degradation by resting cells were isolated by preparative TLC or semi-preparative HPLC, and identified by TLC, MS, NMR, Fourier-transform (FT)-IR and GC-MS analysis. The pathway for nicotine degradation in A. oryzae 112822 was proposed to be from nicotine to 2,3-dihydroxypyridine through the intermediates nornicotine, myosmine, N-methylnicotinamide and 2-hydroxy-N-methylnicotinamide. The ring of 2,3-dihydroxypyridine was opened between the 2- and 3-hydroxy positions to yield succinic acid. N-methylnicotinamide and 2,3-dihydroxypyridine were satisfactorily verified as metabolites of nicotine degradation. This is the first elucidation of a pathway for nicotine degradation in fungi. PMID:20600861

  7. The antifungal activity of Sarcococca saligna ethanol extract and its combination effect with fluconazole against different resistant Aspergillus species.

    PubMed

    Mollazadeh Moghaddam, Kamyar; Arfan, Mohammad; Rafique, Jamal; Rezaee, Sassan; Jafari Fesharaki, Parisa; Gohari, Ahmad Reza; Shahverdi, Ahmad Reza

    2010-09-01

    Microbial resistance is a major drawback in chemotherapy of microbial or fungal infection disease. In this study, the antifungal activity of ethanol extract of a selected plant (Sarcococca saligna) has been investigated against clinical isolates of Aspergillus niger, Aspergillus treus, Aspergillus flavus, and Aspergillus fumigatus. Also, the enhancement of the antifungal activity of fluconazole by this extract was further evaluated against mentioned test strains. Conventional disk diffusion method was used to assay the antifungal activity of S. saligna ethanol extract in the absence and presence of fluconazole. The highest antifungal activity was observed against A. treus. The ethanol extract of S. saligna enhanced the antifungal activity of fluconazole against A. niger and A. treus and A. flavus. At the highest tested contents (4 mg/disk), 1.15-, 0.64-, and 2.47-fold increases in inhibition zone surface area were observed for A. niger, A. treus, and A. flavus, respectively. However, no enhancing effect was observed for this plant extract against Aspergillus fumigates at tested contents (0.5, 1, 2, 3, and 4 mg/disk). In a separate experiment, the general cytotoxicity of the ethanol extract of S. saligna was examined with brine shrimp assay. This plant extract showed low cytotoxicity against Artemia salina (LC(50) = 186 microg/ml). PMID:19685213

  8. Occurrence and biodiversity of Aspergillus section Nigri on 'Tannat' grapes in Uruguay.

    PubMed

    Garmendia, Gabriela; Vero, Silvana

    2016-01-01

    Ochratoxin A (OTA) is a nephrotoxic mycotoxin which has been found worldwide as a contaminant in wines. It is produced on grapes mainly by molds from Aspergillus section Nigri. This study has demonstrated for the first time the occurrence of black aspergilli on Tannat grapes from Uruguay, in a two year survey. Aspergillus uvarum (uniseriate) and Aspergillus welwitschiae (from Aspergillusniger aggregate) were the prevalent species whereas Aspergillus carbonarius which is considered the main OTA producing species was not detected. OTA production in culture medium was evaluated for native isolates from A. niger aggregate and compared to levels produced by a type strain of A. carbonarius. This work also includes the development of quick and easy molecular methods to identify black aspergilli to species level, avoiding sequencing. PMID:26398282

  9. Physiological behaviour of gliotoxigenic Aspergillus fumigatus sensu stricto isolated from maize silage under simulated environmental conditions.

    PubMed

    Alonso, V; Vergara, L Daz; Aminahuel, C; Pereyra, C; Pena, G; Torres, A; Dalcero, A; Cavaglieri, L

    2015-01-01

    Environmental conditions play a key role in fungal development. During the silage production process, humidity, oxygen availability and pH vary among lactic-fermentation phases and among different silage sections. The aim of this work was to study the physiological behaviour of gliotoxicogenic Aspergillus fumigatus strains isolated from maize silage under simulated natural physicochemical conditions - different water activities (a(W)), temperatures (T), pH and oxygen pressure - on the growth parameters (growth rate and lag phase) and gliotoxin production. The silage was made with the harvested whole maize plant that was chopped and used for trench-type silo fabrication. Water activity and pH of the silage samples were determined. Total fungal counts were performed on Dichloran Rose Bengal Chloramphenicol agar and Dichloran 18% Glycerol agar. The morphological identification of A. fumigatus was performed with different culture media and at different growth temperature to observe microscopic and macroscopic characteristics. Gliotoxin production by A. fumigatus was determined by HPLC. All strains isolated were morphologically identified as A. fumigatus. Two A. fumigatus strains isolated from the silage samples were selected for the ecophysiological study (A. fumigatus sensu stricto RC031 and RC032). The results of this investigation showed that the fungus grows in the simulated natural physicochemical conditions of corn silage and produces gliotoxin. The study of the physiological behaviour of gliotoxigenic A. fumigatus under simulated environmental conditions allowed its behaviour to be predicted in silage and this will in future enable appropriate control strategies to be developed to prevent the spread of this fungus and toxin production that leads to impairment and reduced quality of silage. PMID:25599419

  10. Growth and product formation in chemostat and recycling cultures by Aspergillus niger N402 and a glucoamylase overproducing transformant, provided with multiple copies of the glaA gene.

    PubMed

    Schrickx, J M; Krave, A S; Verdoes, J C; van den Hondel, C A; Stouthamer, A H; van Verseveld, H W

    1993-11-01

    Continuous and recycling cultures were carried out with Aspergillus niger N402 wild-type and a glucoamylase overproducing transformant to investigate growth and product formation characteristics. In shake flask cultures, the amount of glucoamylase produced by the transformant was about five times more than by the wild-type strain. In contrast with these results, a twofold overproduction was found in glucose-limited continuous cultures, while no overproduction was found under maltodextrin-limitation. Two regions of specific growth rates could be distinguished, one at specific growth rates lower (domain I) and one at specific growth rates higher than 0.12 h-1 (domain II). In domain I changes in mycelium morphology and conidia formation were observed. It has been concluded that maintenance requirements are dependent on the specific growth rate over the whole range of measured growth rates. The deviation in linearity in the linear equation of substrate utilization, caused by this phenomenon, should be considered when continuous cultures with filamentous fungi are performed. In recycling cultures, xylose as limiting carbon source repressed glucoamylase production very strongly. Under maltodextrin-limitation a fivefold overproduction was found. After about 150 h , the total amount of glucoamylase produced was still increasing, while total amount of product, measured as carbon, remained constant. After this time no increase in the amount of biomass formed was observed. These results suggest autolysis and cryptic growth taking place in a recycling fermenter and cell death rate equalling growth rate. PMID:8277260

  11. Fine substrate specificities of four exo-type cellulases produced by Aspergillus niger, Trichoderma reesei, and Irpex lacteus on (1-->3), (1-->4)-beta-D-glucans and xyloglucan.

    PubMed

    Amano, Y; Shiroishi, M; Nisizawa, K; Hoshino, E; Kanda, T

    1996-12-01

    To investigate the fine substrate specificities of four highly purified exo-type cellulases (Exo-A from Aspergillus niger, CBHI and CBHII from Trichoderma reesei, and Ex-1 from Irpex lacteus), water-soluble substrates such as barley glucan, xyloglucan from tamarind (Tamarindus indica L.), and their oligosaccharides were employed. Four exo-type cellulases immediately hydrolyzed 3-O-beta-D-cellotriosylglucose to produce cellobiose and laminaribiose. In contrast, CBHII showed no hydrolytic activity towards 3(2)-O-beta-D-cello-biosylcellobiose, which was hydrolyzed to cellobiose by the other exo-type cellulases. These cellulases hydrolyzed the internal linkages of barley glucan and lichenan in an endo-type fashion to produce cellobiose and mix-linked oligosaccharides as main products. The DP-lowering activities of the four exo-type cellulases on barley glucan were in the order of Ex-1, CBHII, Exo-A, and CBHI. Based on gel permeation chromatography analysis of the hydrolysates, Ex-1 seemed to attack the internal cellobiosyl unit adjacent to beta-1,3-glucosidic linkages in barley glucan molecule more frequently than did the other cellulases. Xyloglucan was hydrolyzed only by CBHI and CBHII, and produced hepta-, octa-, and nona-saccharides. In addition, a xyloglucan tetradecasaccharide (XG14) was split only to heptasaccharide (XG7) by CBHI and CBHII. PMID:9010760

  12. Purification and characterization of an extracellular keratinolytic protease from a new isolate of Aspergillus parasiticus.

    PubMed

    Anitha, T S; Palanivelu, P

    2013-04-01

    Keratinolytic proteases find extensive applications both in environmental biotechnology and pharmaceutical industries. An extracellular keratinolytic protease was purified and characterized from the fungus, Aspergillus parasiticus, isolated from poultry soil. The enzyme was purified to homogeneity by acetone and ammonium sulfate precipitations followed by CM-Sepharose column chromatography. The molecular mass of the enzyme was 36kDa as judged by SDS-PAGE. The purified keratinase had a pH optimum of 7.0 and temperature optimum of 50(o)C. The enzyme hydrolyzed the substrate azocasein and the Km and Vmax of the purified keratinase were found to be 1.04mg/ml and 3463.34Units/min/mg protein, respectively. The enzyme showed increased activity in the presence of reducing agents. The enzyme was found to be glycosylated. According to the inhibition profiles obtained with the various protease inhibitors, it was confirmed that the purified keratinase belongs to the serine protease type. The purified enzyme activity was enhanced by calcium, magnesium and manganese ions and partially inhibited by cadmium, copper and zinc ions. The purified enzyme showed increased activity with nonionic detergents and urea. PMID:23337085

  13. Intratracheal exposure of rats to Aspergillus fumigatus spores isolated from sawmills in Sweden.

    PubMed Central

    Land, C J; Sostarić, B; Fuchs, R; Lundström, H; Hult, K

    1989-01-01

    Five strains of Aspergillus fumigatus (A, B, D, H, and K) isolated from sawmills were used to expose groups of three rats by intratracheal intubation. The dose was 10(9) spores per rat. At 48 h after administration, two rats from the D group and all rats from the K group died with symptoms of strong dyspnea and tachypnea. At 72 h postadministration and after, some animals showed mild to moderate dyspnea and tachypnea. Autopsies of all animals were performed, including a histopathological examination of the lungs. At 72 h after administration, two distinct morphological groups were identified histopathologically. Severe necrotizing pneumonia characterized by the presence of abundant fungal hyphae was seen in animals that died spontaneously within 48 h postadministration and rats with bronchopneumonia and was characterized by the presence of numerous fungal spores. There was an obvious difference in pathogenicity among the strains of A. fumigatus. Strains D and K were more pathogenic, and only the rats exposed to these strains showed the presence of fungal hyphae in the lungs. The mycotoxin gliotoxin that is produced by A. fumigatus and has antiphagocytic activity was not detected in the spores from any of the A. fumigatus strains. PMID:2483040

  14. Indole Diterpenoids and Isocoumarin from the Fungus, Aspergillus flavus, Isolated from the Prawn, Penaeus vannamei

    PubMed Central

    Sun, Kunlai; Li, Ye; Guo, Lei; Wang, Yi; Liu, Peipei; Zhu, Weiming

    2014-01-01

    Two new indole-diterpenoids (1 and 2) and a new isocoumarin (3), along with the known ?-aflatrem (4), paspalinine (5), leporin B (6), ?-cyclopiazonic acid (7), iso-?-cyclopiazonic acid (8), ditryptophenaline (9), aflatoxin B1 (10), 7-O-acetylkojic acid (11) and kojic acid (12), w