Note: This page contains sample records for the topic aspergillus niger isolated from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

The isolation of Ant1 , a transposable element from Aspergillus niger  

Microsoft Academic Search

A transposable element has been isolated from the industrially important fungus Aspergillus niger (strain N402). The element was identified as an insertion sequence within the coding region of the nitrate reductase gene. It had inserted at a TA site and appeared to have duplicated the target site upon insertion. The isolated element was found to be 4798 by in length

Dianne C. Glayzer; Ian N. Roberts; David B. Archer; Richard P. Oliver

1995-01-01

2

Isolation of epiphytic yeasts with potential for biocontrol of Aspergillus carbonarius and A. niger on grape.  

PubMed

Antagonistic yeasts were isolated from the epiphytic flora associated with grape berries cv. Negroamaro and identified at species level using molecular methods. A total of 144 yeast isolates were tested in a preliminary screening on agar to select isolates showing a killer activity against Aspergillus carbonarius and A. niger, the main species responsible for the accumulation of ochratoxin A in grape. Twenty-eight yeast isolates were selected for their inhibitory effects on the above fungal species and assayed by an in vitro nutritional competition test for their antagonistic capacity towards three selected ochratoxigenic strains. Six yeast isolates belonging to five species, namely 2 isolates of Issatchenkia orientalis and one each of Metschnikowia pulcherrima, Kluyveromyces thermotolerans, Issatchenkia terricola and Candida incommunis, were finally selected and screened on wounded grape berries for their ability to inhibit infection by ochratoxigenic moulds. With the exception of the K. thermotolerans isolate, when inoculated at 10(9) CFU/wound, the other five challenger yeasts reduced the A. carbonarius and A. niger colonization on grape berry (P<0.05). In particular, the best antagonistic activity was shown by the two I. orientalis isolates. Results suggest that antagonist yeasts with the potential to control A. carbonarius and A. niger on grape can be found among the microflora associated with the berries. PMID:16443300

Bleve, Gianluca; Grieco, Francesco; Cozzi, Giuseppe; Logrieco, Antonio; Visconti, Angelo

2006-01-27

3

Ochratoxin A production by strains of Aspergillus niger var. niger.  

PubMed Central

In a survey of the occurrence of ochratoxin A (OA)-positive strains isolated from feedstuffs, two of the 19 isolates of Aspergillus niger var. niger that were studied produced OA in 2% yeast extract-15% sucrose broth and in corn cultures. This is the first report of production of OA by this species.

Abarca, M L; Bragulat, M R; Castella, G; Cabanes, F J

1994-01-01

4

The isolation of Ant1, a transposable element from Aspergillus niger.  

PubMed

A transposable element has been isolated from the industrially important fungus Aspergillus niger (strain N402). The element was identified as an insertion sequence within the coding region of the nitrate reductase gene. It had inserted at a TA site and appeared to have duplicated the target site upon insertion. The isolated element was found to be 4798 bp in length and contained 37-bp inverted, imperfect, terminal repeats (ITRs). The sequence of the central region of the element revealed an open reading frame (designated ORF1) which showed similarity, at the amino acid level, to the transposase of the Tc1/mariner class of DNA transposons. Another sequence within the central region of the element showed similarity to the 3' coding and downstream untranslated region of the amyA gene of A. niger. Sequence homology and structural features indicate that this element, which has been named Ant1 (A. niger transposon 1), is related to the Tc1/mariner group of DNA transposons. Ant1 is apparently present as a single copy in strain N402 of A. niger. PMID:8552048

Glayzer, D C; Roberts, I N; Archer, D B; Oliver, R P

1995-12-10

5

Isolation and characterization of a novel antifungal peptide from Aspergillus niger.  

PubMed

A novel antifungal peptide (termed as Anafp) was isolated from the culture supernatant of the filamentous fungi, Aspergillus niger. The whole amino acid sequence of Anafp was determined and the peptide was found to be composed of a single polypeptide chain with 58 amino acids including six cysteine residues. The peptide shows some degree of sequence homology to a cysteine-rich antifungal peptides reported from the seeds of Sinapis alba and Arabidopsis thaliana or the extracellular media of Aspergillus giganteus and Penicillium chrysogenumsome. Cysteine-spacing pattern of Anafp was similar to that of the antifungal peptide from Penicillium chrysogenum. The Anafp exhibited potent growth inhibitory activities against yeast strains as well as filamentous fungi at a range from 4 to 15 microM. In contrast, Anafp did not show antibacterial activity against Escherichia coli and Bacillus subtilis even at 50 microM. PMID:10512732

Gun Lee, D; Shin, S Y; Maeng, C Y; Jin, Z Z; Kim, K L; Hahm, K S

1999-10-01

6

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

SciTech Connect

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.

Buckova, M.; Godocikova, J.; Simonovicova, A.; Polek, B. [Slovakian Academy of Science, Bratislava (Slovakia)

2005-04-15

7

Isolation by genetic complementation of two differentially expressed genes for ?-isopropylmalate dehydrogenase from Aspergillus niger  

Microsoft Academic Search

We have constructed an Aspergillus niger cDNA library with a yeast expression vector. The library DNA complemented a leucine auxotroph of Saccharomyces cerevisiae (strain BWG1-7a) at a frequency of 4×10-4. Plasmids rescued from the yeast prototrophs also complemented Escherichia coli (strain MC1066) deficient in leucine biosynthesis. Sequence determination of the rescued plasmids revealed two genes for\\u000a ?-isopropylmalate dehydrogenase, which we

B. A. Williams; S. Sillaots; A. Tsang; R. Storms

1996-01-01

8

Degradation of chlorimuron-ethyl by Aspergillus niger isolated from agricultural soil.  

PubMed

Chlorimuron-ethyl, ethyl-2-[[[[(4-methoxy-6-chloro-pyrimidin-2-yl)amino]carbonyl]amino] sulfonyl]benzoate, is used as a pre- and postemergence herbicide for the control of important broadleaved weeds in soybean and maize. Due to its phytotoxicity to rotation crops, concerns regarding chlorimuron contamination of soil and water have been raised. Although it is degraded in the agricultural environment primarily via pH- and temperature-dependent chemical hydrolysis, microbial transformation also has an important role. Fungi such as Fusarium and Alternaria are unable to survive in artificial media containing chlorimuron-ethyl at 25 mg L(-1) . However, Aspergillus niger survived in minimal broth containing chlorimuron at 2 mg mL(-1) . Aspergillus niger degraded the herbicide to harvest energy through two major routes of degradation. One route involves the cleavage of the sulfonylurea bridge, resulting in the formation of two major metabolites, namely ethyl-2-aminosulfonylbenzoate (I) and 4-methoxy-6-chloro-2-amino-pyrimidine (II). The other route is the cleavage of sulfonylamide linkage, which generates the metabolite N-(4-methoxy-6-chloropyrimidin-2-yl) urea (III). Two other metabolites, saccharin (IV) and N-methyl saccharin (V), formed from metabolite II, were also identified. A metabolic pathway for the degradation of chlorimuron-ethyl by A. niger has been proposed. PMID:22967225

Sharma, Seema; Banerjee, Kaushik; Choudhury, Partha P

2012-10-29

9

Lysine aminopeptidase of Aspergillus niger  

Microsoft Academic Search

Conserved regions within the M1 family of metallo-aminopeptidases have been used to clone a zinc aminopeptidase from the industrially used fungus Aspergillus niger. The derived amino acid sequence of ApsA is highly similar to two yeast zinc aminopeptidases, LAPI and AAPI (53.3 and 50.9?verall similarity, respectively), two members of the M1 family of metallo-aminopeptidases. The encoding gene was successfully overexpressed

D. E. J. W. Basten; Jaap Visser; Peter J. Schaap

2001-01-01

10

Citric acid production by a novel Aspergillus niger isolate: I. Mutagenesis and cost reduction studies.  

PubMed

Ultraviolet-irradiation (UV), ethyl methane sulfonate (EMS) and acridine orange (AO) were used to induce citric acid overproduction mutations in Aspergillus niger UMIP 2564. Among 15, eight of the mutant derivatives, were improved with respect to citric acid production from sucrose in batch cultures. Maximum product yield (60.25%) was recorded by W5, a stable UV mutant, with approximately 3.2-fold increase when compared to the parental wild type strain. In terms of the kinetic parameters for batch fermentation processes, the mutation doubled the specific substrate uptake rate and achieved 4.5- and 7.5-fold improvements in citric acid productivity and specific productivity, respectively. For reduction of the fermentation medium cost, corn steep liquor and calcium phosphate pre-treated beet molasses were successfully used as substituents of nitrogen and carbon sources in the growth medium, respectively. These medium substitutions resulted in a W5 citric acid fermentation culture with a product yield of 74.56%. PMID:17223558

Lotfy, Walid A; Ghanem, Khaled M; El-Helow, Ehab R

2007-01-12

11

Heavy metal biosorption sites in Aspergillus niger  

Microsoft Academic Search

Aspergillus niger is capable of removing heavy metals such as lead, cadmium and copper from aqueous solutions. The role played by various functional groups in the cell wall of A. niger in biosorption of lead, cadmium and copper was investigated. The biomass was subjected to chemical treatments to modify the functional groups, carboxyl, amino and phosphate, to study their role

Anoop Kapoor; T. Viraraghavan

1997-01-01

12

Single cell transcriptomics of neighboring hyphae of Aspergillus niger  

PubMed Central

Single cell profiling was performed to assess differences in RNA accumulation in neighboring hyphae of the fungus Aspergillus niger. A protocol was developed to isolate and amplify RNA from single hyphae or parts thereof. Microarray analysis resulted in a present call for 4 to 7% of the A. niger genes, of which 12% showed heterogeneous RNA levels. These genes belonged to a wide range of gene categories.

2011-01-01

13

Reactive dye bioaccumulation by fungus Aspergillus niger isolated from the effluent of sugar fabric-contaminated soil.  

PubMed

The present study dealt with the decolorization of textile dye Reactive Black-5 by actively growing mycelium of Aspergillus niger MT-1 in molasses medium. It was found that the fungus, which was isolated from the effluent of sugar fabric-contaminated soil, was capable of decolorizing the Reactive Black-5 dye in a wide range of temperature, shaking speed and pH values. The experiments also revealed that highest dye decolorization efficiency was achieved with cheap carbon (molasses sucrose) and nitrogen (ammonium chloride) sources. Under the optimized culture conditions, the complete decolorization (100%) of 0.1 g/L dye was achieved in 60 hours. The dominant mechanism of dye removal by the fungus was found to be probably bioaccumulation. Fungal growth in small uniform pellet form was found to be better for dye bioacumulation. Molass as carbon source increased dye bioaccumulation by stimulating the mycelial growth in small uniform pellet form. The maximum bioaccumulation efficiency of fungus for dye was 91% (0.273 g bioaccumulated dye) at an initial dye concentration of 0.3 g/L in 100 hours. It was shown for the first time in the present study that the effluent of sugar fabric-contaminated soil was a good source of microorganisms, being capable of decolorizing snythetic textile dyes. PMID:20237194

Taskin, Mesut; Erdal, Serkan

2010-03-17

14

Screening of Urease Production by Aspergillus niger Strains  

Microsoft Academic Search

In this study, urease production was investigated among thirteen strains of Aspergillus niger; seven strains isolated from soils of Semnan province in Iran and six strains obtained from Persian Type Culture Collection (PTCC). The enzyme production was screened in two submerged media quantitatively. The registered PTCC 5011 and the native S31 strains showed more urease production than the other eleven

Mohammad Faezi Ghasemi; Mohammad Reza Bakhtiari; Masoud Fallahpour; Ashrafossadat Noohi; Nasrin Moazami; Zohreh Amidi

15

Acute aortic occlusion with sudden paraplegia secondary to Aspergillus niger embolism from Aspergillus niger aortitis.  

PubMed

Acute aortic occlusion caused by a saddle embolus is a rare vascular emergency. Associated sudden paraplegia secondary to spinal cord ischemia is even more uncommon. Aspergillus surgical site infection is typically linked to cardiac surgery but is exceptional. Here we present a case that combines all of these factors. A 67-year-old man presented with sudden paraplegia from acute aortic occlusion with a saddle embolus from Aspergillus niger aortitis 4 months after aortic valve replacement and aortoplasty. We believe this to be the second reported case of Aspergillus niger aortitis and the first presenting as aortic occlusion with paraplegia. PMID:21715126

Jamieson, Russell W; Wallace, William A; Din, Jehangir N; Raza, Zahid

2011-06-29

16

Purification and Characterization of a Dimethoate-Degrading Enzyme of Aspergillus niger ZHY256, Isolated from Sewage  

PubMed Central

A dimethoate-degrading enzyme from Aspergillus niger ZHY256 was purified to homogeneity with a specific activity of 227.6 U/mg of protein. The molecular mass of the purified enzyme was estimated to be 66 kDa by gel filtration and 67 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was found to be 5.4, and the enzyme activity was optimal at 50°C and pH 7.0. The activity was inhibited by most of the metal ions and reagents, while it was induced by Cu2+. The Michaelis constant (Km) and Vmax for dimethoate were 1.25 mM and 292 ?mol min?1 mg of protein?1, respectively.

Liu, Yu-Huan; Chung, Ying-Cheng; Xiong, Ya

2001-01-01

17

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

Code of Federal Regulations, 2010 CFR

...and cellulase derived from Aspergillus niger. 173.120 Section 173.120 ...and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger may be safely used in food in...

2010-01-01

18

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

Code of Federal Regulations, 2010 CFR

...and cellulase derived from Aspergillus niger. 173.120 Section 173.120 ...and cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger may be safely used in food in...

2009-04-01

19

Production of 3,4-dihydroxy L-phenylalanine by a newly isolated Aspergillus niger and parameter significance analysis by Plackett-Burman design  

PubMed Central

Background The amino acid derivative 3,4-dihydroxy L-phenylalanine (L-dopa) is gaining interest as a drug of choice for Parkinson's disease. Aspergillus oryzae is commonly used for L-dopa production; however, a slower growth rate and relatively lower tyrosinase activity of mycelia have led to an increasing interest in exploiting alternative fungal cultures. In the present investigation, we report on the microbiological transformation of L-tyrosine to L-dopa accomplished by a newly isolated filamentous fungus Aspergillus niger. Results The culture A. niger (isolate GCBT-8) was propagated in 500 ml Erlenmeyer flasks and the pre-grown mycelia (48 h old) were used in the reaction mixture as a source of enzyme tyrosinase. Grinded mycelia gave 1.26 fold higher L-dopa production compared to the intact at 6% glucose (pH 5.5). The rate of L-tyrosine consumption was improved from 0.198 to 0.281 mg/ml. Among the various nitrogen sources, 1.5% peptone, 1% yeast extract and 0.2% ammonium chloride were optimized. The maximal L-dopa was produced (0.365 mg/ml) at 0.3% potassium dihydrogen phosphate with L-tyrosine consumption of 0.403 mg/ml. Conclusion Over ~73% yield was achieved (degree of freedom 3) when the process parameters were identified using 2k-Plackett-Burman experimental design. The results are highly significant (p ? 0.05) and mark the commercial utility (LSD 0.016) of the mould culture which is perhaps the first ever report on L-dopa production from A. niger.

2010-01-01

20

Mutagenesis and genetic characterisation of amylolytic Aspergillus niger  

Microsoft Academic Search

Aspergillus niger FCBP-198 was genetically modified for its ability to reveal extra cellular ?-amylase enzyme activity. From 76 efficient mutants isolated after ultraviolet (UV) irradiation, An-UV-5.6 was selected as the most efficient UV mutant, with 76.41 units mL of ?-amylase activity compared to wild (34.45 units mL). In case of ethyl methane sulphonate (EMS), among 242 survivors, 74 were assayed

Sobiya Shafique; Rukhsana Bajwa; Shazia Shafique

2010-01-01

21

Solid State Bioconversion of Oil Palm Empty Fruit Bunches for Production of Citric Acid by Wild Strains of Aspergillus Niger  

Microsoft Academic Search

This study investigated the potential of Aspergillus niger strains for the production of citric acid from oil palm empty fruit bunches (EFB) through solid state bioconversion (SSB). Twenty six wild strains of Aspergillus niger isolated from lemon, orange, and sewage treatment plant sludge were evaluated. Factors considered in the study were citric acid production, sugar consumption, and protein content as

Zahangir Alam; Niamul Bari; Suleyman A. Muyibi; Parveen Jamal; Abdullah-Al-Mamun

2010-01-01

22

Susceptibility testing of Aspergillus niger strains isolated from poultry to antifungal drugs--a comparative study of the disk diffusion, broth microdilution (M 38-A) and Etest methods.  

PubMed

The aim of this study was to determine the sensitivity of Aspergillus niger strains isolated from birds to available antifungal drugs using different in vitro assays--classical disk diffusion, Etest and broth microdilution NCCLS/CLSI M 38-A. The study material consisted of about 2.000 swabs and samples from different species of birds. A. niger (n=10) was accounted for 6.81% of the total pool of strains isolated. Determinations were made for 13 antifungal drugs using the disk diffusion method. The A. niger exhibited high susceptibility to enilconazole, terbinafine, voriconazole, tioconazole and ketoconazole, low susceptibility to clotrimazole, miconazole and nystatin, and resistance to amphotericin B, itraconazole, pimaricin, fluconazole and 5-fluorocytosine. Minimum inhibitory concentration (MIC) was determined for 9 antifungal drugs using the micromethod of duplicate serial dilutions in a liquid medium. A. niger strains were most susceptible to enilconazole and voriconazole. MIC ranged from 0.0625 to 0.5 microg/ml for enilconazole, with MIC90-0.5 microg/ml and MIC50-0.125 microg/ml. The corresponding values for voriconazole were 0.25-1 microg/ml, 1 microg/ml and 0.5 microg/ml. MIC for amphotericin B and terbinafine ranged from 0.5 to 4 microg/ml, while the values for the remaining drugs were highly varied. MIC was measured by the gradient diffusion method using Etest for 5 antifungal drugs: amphotericin B, fluconazole, itraconazole, ketoconazole and voriconazole. By far the highest susceptibility was obtained in the case of voriconazole, with MIC ranging from 0.0625 to 1 microg/ml. MIC for amphotericin B ranged from 0.25 to 4 microg/ml, for itraconazole and ketoconazole ranging from 0.5 to 16 microg/ml. Methods available for this purpose are not always applicable in field conditions. The present results indicate that the Etest technique, due to its high percentage of agreement with the M 38-A microdilution method, should find application in medical and veterinary practice. PMID:22708367

Tokarzewski, S; Zió?kowska, G; Nowakiewicz, A

2012-01-01

23

Cloning and use of sC as homologous marker for Aspergillus niger transformation.  

PubMed

The sC sequence from Aspergillus niger was cloned and developed into a homologous marker system for genetic transformation. The coding region of the sC gene amplified by PCR from the A. niger genome was provided with Aspergillus nidulans expression signals (gpdA promoter and trpC terminator). This chimeric construct was used to successfully transform a spontaneous sC- isolate of A. niger to prototrophy. The transformants analyzed by Southern analysis showed integration of multiple copies of the transforming DNA. They also exhibited much higher ATP sulfurylase activity than the wild-type A. niger strain reinforcing the molecular data. This demonstrates the usefulness of the sCniger construct, driven by PgpdA, as a marker for A. niger transformation. PMID:15722148

Varadarajalu, Lakshmi P; Punekar, Narayan S

2004-12-19

24

Stable accumulation of Aspergillus niger phytase in transgenic tobacco leaves.  

PubMed Central

Phytase from Aspergillus niger increases the availability of phosphorus from feed for monogastric animals by releasing phosphate from the substrate phytic acid. A phytase cDNA was constitutively expressed in transgenic tobacco (Nicotiana tabacum) plants. Secretion of the protein to the extracellular fluid was established by use of the signal sequence from the tobacco pathogen-related protein S. The specific phytase activity in isolated extracellular fluid was found to be approximately 90-fold higher than in total leaf extract, showing that the enzyme was secreted. This was confirmed by use of immunolocalization. Despite differences in glycosylation, specific activities of tobacco and Aspergillus phytase were identical. Phytase was found to be biologically active and to accumulate in leaves up to 14.4% of total soluble protein during plant maturation. Comparison of phytase accumulation and relative mRNA levels showed that phytase stably accumulated in transgenic leaves during plant growth.

Verwoerd, T C; van Paridon, P A; van Ooyen, A J; van Lent, J W; Hoekema, A; Pen, J

1995-01-01

25

Induction of sorbitol dehydrogenase by sorbitol in Aspergillus niger  

Microsoft Academic Search

Evidence is presented for the simultaneous induction of sorbitol dehydrogenase along with fructokinase and repression of glucokinase by sorbitol in Aspergillus niger. Fructose is the first product of sorbitol catabolism.

B. M. Desai; V. V. Modi; V. K. Shah

1967-01-01

26

Characterization of Humanized Antibodies Secreted by Aspergillus niger  

Microsoft Academic Search

Two different humanized immunoglobulin G1() antibodies and an Fab fragment were produced by Aspergillus niger. The antibodies were secreted into the culture supernatant. Both light and heavy chains were initially synthesized as fusion proteins with native glucoamylase. After antibody assembly, cleavage by A. niger KexB protease allowed the release of free antibody. Purification by hydrophobic charge induction chromatog- raphy proved

Michael Ward; Cherry Lin; Doreen C. Victoria; Bryan P. Fox; Judith A. Fox; David L. Wong; Hendrik J. Meerman; Jeff P. Pucci; Robin B. Fong; Meng H. Heng; Naoya Tsurushita; Christine Gieswein; Minha Park; Huaming Wang

2004-01-01

27

Properties of ?-glucosidase purified from Aspergillus niger mutants USDB 0827 and USDB 0828  

Microsoft Academic Search

Two extracellular ß-glucosidases (EC 3.2.1.21) were isolated from Aspergillus niger USDB 0827 and A. niger USDB 0828, and their physical and kinetic properties studied. Both enzymes were very similar in terms of molecular size (230000 Da), pH optimum (pH 4.6), temperature optimum (65° C), stability at high temperatures and substrate preferences. They were capable of hydrolysing ß-linked disaccharides, phenyl ß-d-glucoside,

Yin Kiong Hoh; Hock-Hin Yeoh; Teck Koon Tan

1992-01-01

28

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

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

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

2009-02-24

29

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

Code of Federal Regulations, 2013 CFR

...PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and Microorganisms § 173...Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger... from the carbohydrase and cellulase enzyme product. (d) The additive is...

2013-04-01

30

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

Microsoft Academic Search

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

Mikael R. Andersen; Margarita Salazar; P. J. Schaap; Peter van de Vondervoort; David E. Culley; Peter J. I. van de Vondervoot; Jens C. Frisvad; Kristian F. Nielsen; Richard Albang; Kristen F. Nielsen; Gerhard Braus; Susanna A. Braus-Stromeyer; Luis Corrochano; Gerald Hofmann; Piet W. M. van Dijck; Hildegard Menke; Jon K. Magnusson; Susan L. Meijer; Jakob B. Nielsen; Michael L. Nielsen; Albert J. J. van Ooyen; Kathyrn S. Panther; Lars Poulsen; Rob A. Samson; Adrian Tsang; Johannes M. van den Brink; Andrea Aerts; Harris Shapiro; Jasmyn Pangilinan; Asaf Salamov; Erika Lindquist; Jane Grimwood; Igor V. Grigoriev; Christian P. Kubicek; Diego Martinez; Johannes A. Roubos; Jens B. Nielsen; Scott E. Baker

2011-01-01

31

Characterization of a novel endopolygalacturonase from Aspergillus niger with unique kinetic properties.  

PubMed

We isolated and characterized a new type of endopolygalacturonase (PG)-encoding gene, pgaD, from Aspergillus niger. The primary structure of PGD differs from that of other A. niger PGs by a 136 amino acid residues long N-terminal extension. Biochemical analysis demonstrated extreme processive behavior of the enzyme on oligomers longer than five galacturonate units. Furthermore, PGD is the only A. niger PG capable of hydrolyzing di-galacturonate. It is tentatively concluded that the enzyme is composed of four subsites. The physiological role of PGD is discussed. PMID:10675564

Parenicová, L; Kester, H C; Benen, J A; Visser, J

2000-02-11

32

Polymerase chain reaction (PCR) identification of Aspergillus niger and Aspergillus tubingensis based on the calmodulin gene.  

PubMed

Aspergillus niger and A. tubingensis, species belonging to section Nigri, are commonly found in plant products and processed food, such as grapes, cereals, coffee, and derived products. These two species are very difficult to differentiate by classical morphological criteria and some isolates are known to produce ochratoxin A. The exact identification of these two species is very important to avoid the overestimation of toxicological contamination and related risks. A polymerase chain reaction (PCR)-based identification and detection assay was developed as a tool to identify A. niger and A. tubingensis, using molecular differences obtained by sequencing the calmodulin gene. Two pairs of species-specific primers were designed and empirically evaluated for PCR identification of A. niger and A. tubingensis. Species-specific PCR products generated by each primer set were 505 bp (A. tubingensis) and 245 bp (A. niger) in length, which could be potentially useful for a multiplex PCR assay. The sensitivity of this assay was about 10 pg DNA in a 25-microl PCR reaction volume, using pure total DNA of the two species. The method described in this study represents a rapid and reliable procedure to assess the presence in food products of two ochratoxigenic species of section Nigri. PMID:17886188

Susca, A; Stea, G; Mulè, G; Perrone, G

2007-10-01

33

Aspergillus Niger Genomics: Past, Present and into the Future  

SciTech Connect

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.

Baker, Scott E.

2006-09-01

34

Nutrient and Anti-nutrient Contents of Aspergillus niger Fermented Cassava Products (Flour and Gari)  

Microsoft Academic Search

Pure strain of Aspergillus niger was isolated and cultured using potato dextrose agar and broth, respectively. This was subsequently used to ferment six portions of 1 kg each of cassava pulp for 72 h. Three portions of the fermented cassava were each sieved and fried in a hot pan to gari, while the other three portions were each sun-dried and

G. Oboh; A. A. Akindahunsi; A. A. Oshodi

2002-01-01

35

[Hypersensitivity pneumonitis induced by Aspergillus niger--a case report].  

PubMed

A 52-year-old woman was hospitalized because of severe cough in August 1994. She had engaged in culturing roses in greenhouses since 1968, and had developed a cough during the summer of 1990. Chest radiography showed diffuse ground-glass opacity in both lung fields, and she suffered from hypoxemia (PaO2 = 45.6 torr) while breathing room air. The lymphocyte count in the bronchoalveolar lavage fluid was increased, and transbronchial lung biopsy specimens showed lymphocyte alveolitis in the alveolar spaces. After admission, the patient's symptoms improved rapidly without medication. However, on her return to work, the cough and hypoxemia reappeared. In her rose culture, she had used Rockwool, and Aspergillus niger was detected predominantly in the Rockwool. Precipitins against the extracts of Aspergillus niger were detected with the double immunodiffusion test and the inhalation provocation test yielded clinical symptoms. Our diagnosis was hypersensitivity pneumonitis caused by Aspergillus niger. PMID:15357273

Miyazaki, Hiroo; Gemma, Hitoshi; Uemura, Keiichi; Ono, Takahisa; Masuda, Masafumi; Sano, Takehisa; Sato, Masaki; Koshimizu, Naoki; Suda, Takafumi; Chida, Kingo

2004-07-01

36

Aspergillus niger: an unusual cause of invasive pulmonary aspergillosis.  

PubMed

Infections due to Aspergillus species cause significant morbidity and mortality. Most are attributed to Aspergillus fumigatus, followed by Aspergillus flavus and Aspergillus terreus. Aspergillus niger is a mould that is rarely reported as a cause of pneumonia. A 72-year-old female with chronic obstructive pulmonary disease and temporal arteritis being treated with steroids long term presented with haemoptysis and pleuritic chest pain. Chest radiography revealed areas of heterogeneous consolidation with cavitation in the right upper lobe of the lung. Induced bacterial sputum cultures, and acid-fast smears and cultures were negative. Fungal sputum cultures grew A. niger. The patient clinically improved on a combination therapy of empiric antibacterials and voriconazole, followed by voriconazole monotherapy. After 4 weeks of voriconazole therapy, however, repeat chest computed tomography scanning showed a significant progression of the infection and near-complete necrosis of the right upper lobe of the lung. Serum voriconazole levels were low-normal (1.0 microg ml(-1), normal range for the assay 0.5-6.0 microg ml(-1)). A. niger was again recovered from bronchoalveolar lavage specimens. A right upper lobectomy was performed, and lung tissue cultures grew A. niger. Furthermore, the lung histopathology showed acute and organizing pneumonia, fungal hyphae and oxalate crystallosis, confirming the diagnosis of invasive A. niger infection. A. niger, unlike A. fumigatus and A. flavus, is less commonly considered a cause of invasive aspergillosis (IA). The finding of calcium oxalate crystals in histopathology specimens is classic for A. niger infection and can be helpful in making a diagnosis even in the absence of conidia. Therapeutic drug monitoring may be useful in optimizing the treatment of IA given the wide variations in the oral bioavailability of voriconazole. PMID:20299503

Person, A K; Chudgar, S M; Norton, B L; Tong, B C; Stout, J E

2010-03-18

37

Bioaccumulation potential of Aspergillus niger and Aspergillus flavus for removal of heavy metals from paper mill effluent.  

PubMed

In the present study Aspergillus niger and Aspergillus flavus isolated from paper mill effluent showed tolerance and accumulation of toxic metals Ni, Zn, Cd, Pb, Cr and Cu from synthetic medium and paper mill effluent. Physico-chemical and heavy metals characterization of industrially treated paper mill effluent showed insignificant reduction in BOD, hardness, TDS and heavy metals as compared to permissible limits of BIS and WHO. A. niger and A. flavus were treated with synthetic medium containing 100-1000 mg l(-1) of six heavy metals. A. niger was able to tolerate and grow in 1000 mg l(-1) Pb, 500 mg l(-1) Cu, 250 mg l(-1) Zn and 100 mg l(-1) Cr, Ni respectively. No growth of A. niger was observed in 100 mg l-(-1) of Cd. A. flavus was capable to tolerate and grow in 1000 mg l(-1) Pb, Zn and Ni, 100mg l(-1) Cu. A. flavus growth was completely inhibited in 100 mg l(-1) of Cd and Cr. The Cd, Zn, Cu and Pb reduction were found significant (p < 0.05) in the paper effluent inoculated with A. niger and A. flavus biomass compared to industrial treated effluent. A. niger and A. flavus accumulated maximum of Pb (75.82%) followed by Zn (49.40%) > Cu (45.34%) > Ni (25.20%), while only 41% Cr was accumulated by A. nigerfrom 100 mg l(-1) of Cr solution. PMID:23741802

Thippeswamy, B; Shivakumar, C K; Krishnappa, M

2012-11-01

38

Studies on the Production of Fungal Peroxidases in Aspergillus niger  

Microsoft Academic Search

To get insight into the limiting factors existing for the efficient production of fungal peroxidase in filamen- tous fungi, the expression of the Phanerochaete chrysosporium lignin peroxidase H8 (lipA) and manganese peroxidase (MnP) H4 (mnp1) genes in Aspergillus niger has been studied. For this purpose, a protease-deficient A. niger strain and different expression cassettes have been used. Northern blotting experiments

ANA CONESA; CEES A. M. J. J. VAN DEN HONDEL; PETER J. PUNT

2000-01-01

39

Genetic analysis of resistance to fenpropimorph in Aspergillus niger  

Microsoft Academic Search

Resistance to the morpholine-fungicide fenpropimorph was studied in Aspergillus niger and A. nidulans. Mass selection of conidia of A. nidulans on agar amended with the fungicide at different concentrations did not yield of resistant mutants, even after UV-treatment\\u000a of the conidia. In contrast, similar experiments with A. niger generated many fenpropimorph-resistant mutants. The mutants displayed cross-resistance to fenpropidin and generally

A. J. G. Engels; E. F. Holub; K. Swart; M. A. De Waard

1998-01-01

40

Removal of heavy metals using the fungus Aspergillus niger  

Microsoft Academic Search

There is a need to develop technologies that can remove toxic heavy metal ions found in wastewaters. Microorganisms are known to remove heavy metal ions from water. In this study the potential of the fungus Aspergillus niger to remove lead, cadmium, copper and nickel ions was evaluated. A. niger biomass pretreated by boiling in 0.1N NaOH solution for 15 min

Anoop Kapoor; T Viraraghavan; D. Roy Cullimore

1999-01-01

41

Mannitol is required for stress tolerance in Aspergillus niger conidiospores  

Microsoft Academic Search

D-Mannitol is the predominant carbon compound in conidiospores of the filamentous fungus Aspergillus niger and makes up 10 to 15?f the dry weight. A number of physiological functions have been ascribed to mannitol, including serving as a reserve carbon source, as an antioxidant, and to store reducing power. In this study, we cloned and characterized the A. niger mpdA gene,

George J. G. Ruijter; Maarten Bax; Hema Patel; Simon J. Flitter; Vondervoort van de P. J. I; Vries de R. P; Kuyk van P. A; Jaap Visser

2003-01-01

42

Citric acid production by Aspergillus niger immobilized on polyurethane foam  

Microsoft Academic Search

Citric acid was produced using Aspergillus niger immobilized on polyurethane foam in a bubble column reactor. Most of the adsorbed cells remained on the support and, as a result, high oxygen tension was maintained during the reactor operation. However, uncontrolled growth of the pellets made continuous reactor operation difficult. The citric acid productivity obtained from 15 vol.% foam particles containing

Yong Hee Lee; Chang Woo Lee; Ho Nam Chang

1989-01-01

43

Color elimination from molasses wastewater by Aspergillus niger  

Microsoft Academic Search

Color elimination by Aspergillus niger from wastewater from molasses alcoholic fermentation was studied. The influences of the nutrient concentrations, initial pH and carbon source on this color elimination were analyzed. It worked in a discontinuous process in shaken cultures and in a continuous process in a bubble reactor. During the batch process, through all experiments the maximal color elimination was

M. Peña Miranda; G. González Benito; N. San Cristobal; C. Heras Nieto

1996-01-01

44

Biotransformation of quinazoline and phthalazine by Aspergillus niger.  

PubMed

Cultures of Aspergillus niger NRRL-599 in fluid Sabouraud medium were grown with quinazoline and phthalazine for 7 days. Metabolites were purified by high-performance liquid chromatography and identified by mass spectrometry and proton nuclear magnetic resonance spectroscopy. Quinazoline was oxidized to 4-quinazolinone and 2,4-quinazolinedione, and phthalazine was oxidized to 1-phthalazinone. PMID:21169055

Sutherland, John B; Heinze, Thomas M; Schnackenberg, Laura K; Freeman, James P; Williams, Anna J

2010-12-18

45

Utilization of Brewery Spent Grain Liquor by Aspergillus niger1  

PubMed Central

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%.

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

1975-01-01

46

Phenethyl-?-pyrone derivatives and cyclodipeptides from a marine algous endophytic fungus Aspergillus niger EN–13  

Microsoft Academic Search

Two new phenethyl-?-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-?-pyrone derivative (pyrophen, 3) and three cyclodipeptides (4–6), were also isolated and identified. The structures of these compounds

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

2010-01-01

47

Response surface methodology (RSM) analysis of organic acid production for Kaolin beneficiation by Aspergillus niger  

Microsoft Academic Search

In the present investigation, Aspergillus niger isolated from pistachio shell was applied to remove iron impurities from an Iranian kaolin sample. In order to study the effects of initial pH, sucrose and spore concentration on oxalic and citric acid production, and consequently iron dissolution, response surface methodology based on a five-level, three-variable central composite design of experiments was employed. Three

E. Aghaie; M. Pazouki; M. R. Hosseini; M. Ranjbar; F. Ghavipanjeh

2009-01-01

48

Regulation of 6-phosphofructo-2-kinase from the citric-acid-accumulating fungus Aspergillus niger  

Microsoft Academic Search

Summary Phosphofructokinase 2 (PFK 2) was isolated from mycelia of the citric-acid-accumulating fungus Aspergillus niger, and partially purified by Trisacryl-Blue chromatography and Mono Q fast protein liquid chromatography. The appearance of a 96\\/94-kDa double band correlated with PFK 2 activity during purification. Purified PFK 2 had a half-life of 240 min at 4° C. The enzyme exhibited Michaelis-Menten type kinetics

Hermie J. M. Harmsenl; Eva M. Kubicek-Pranz; Max Röhr; Jaap Visser; Christian P. Kubicek

1992-01-01

49

Aspergillus niger pH 2.1 optimum acid phosphatase with high affinity for phytate  

Microsoft Academic Search

An extracellular acid phosphatase isolated from the culture of a wild strainAspergillus niger, producing the dephosphorylating 3-phytase, was obtained in a homogeneous form by sequential application of ultrafiltration\\u000a through PS 50 membrane, gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-Sepharose CL 6B and CM-Sepharose\\u000a CL 6B. The enzyme showed a maximum catalytic value in a strongly acidic

S. Gargova; M. Sariyska; A. Angelov; I. Stoilova

2006-01-01

50

Optimization of extraction of ?-endoglucanase from the fermented bran of Aspergillus niger  

Microsoft Academic Search

A local isolate of Aspergillus niger was cultivated under optimal growth conditions on wheat bran in solid state fermentation. ?-endoglucanase from fermented\\u000a bran was separately extracted with different solvents to test recovery of enzyme. Among solvents tested, distilled water served\\u000a the best leachate. Conditions were further optimized with this leachate. Two washes of fermented bran with the leachate for\\u000a 30

M. Subhosh Chandra; Buddolla Viswanath; B. Rajasekhar Reddy

2010-01-01

51

Antifungal activity of lauric acid derivatives against Aspergillus niger  

Microsoft Academic Search

The antifungal effects of lauric acid and four lauric acid derivatives (monolauroylglycerol, D-laurate A, T-laurate A, 6-O-lauroysucrose) were tested on the spore germination and the growth rate of Aspergillus niger DMF 0801. The results showed that the tested substances varied in their antifungal activity and they also confirmed the relation of the structure of tested substances and their antifungal effects.

Zde?ka ?iháková; Milada Plocková; Vladimír Filip; Jan Šmidrkal

2001-01-01

52

Adaptation of Aspergillus niger to short-term salt strees  

Microsoft Academic Search

Adaptation of filamentous fungi to short-term salt stress has been analysed by a continuous measurement system. Spores of Aspergillus niger were immobilized on the polylysine-coated glass bottom of a culture vessel, which enabled the exchange of a medium containing salt (NaCl) without disturbing continuous observation. Repeated contacts with 0.75% NaCl produced hypha insensitive to this concentration of NaCl. When the

Jong-Chul Park; Yasuyuki Nemoto; Tomoo Homma; Weimin Jing; Yuansong Chen; Hideaki Matsuoka; Hirokazu Ohno; Kosuke Takatori; Hiroshi Kurata

1993-01-01

53

Optimized bioprocess for production of fructofuranosidase by recombinant Aspergillus niger  

Microsoft Academic Search

A comprehensive approach of bioprocess design at various levels was used to optimize microbial production of extracellular\\u000a fructofuranosidase, important as biocatalyst to derive fructooligosaccharides with broad application in food or pharmaceutical\\u000a industry. For production, the recombinant strain Aspergillus niger SKAn1015 was used, which expresses the fructofuranosidase encoding gene suc1 under control of a strong constitutive promoter. In a first screening

Habib Driouch; Andreas Roth; Petra Dersch; Christoph Wittmann

2010-01-01

54

Purification and immobilization of Aspergillus niger. beta. -xylosidase  

SciTech Connect

..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.

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

1980-01-01

55

Analytical and computational approaches to define the Aspergillus niger secretome  

SciTech Connect

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.

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

2009-03-01

56

Six novel constitutive promoters for metabolic engineering of Aspergillus niger.  

PubMed

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 570 mg/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

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

2012-06-16

57

Transcriptome analysis of Aspergillus niger grown on sugarcane bagasse  

PubMed Central

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.

2011-01-01

58

Production of Fumonisin B2 and B4 by Aspergillus niger on grapes and raisins.  

PubMed

The recent discovery of fumonisin production in Aspergillus niger, raises concerns about the presence of these mycotoxins in grapes and raisins as well as other commodities where A. niger is a frequent contaminant. Here we investigate the potential production of fumonisins in A. niger cultured on grapes and raisins. Sixty-six A. niger, 4 A. tubingensis, and 16 A. acidus strains isolated from raisins were tested for fumonisin production on laboratory media. Neither A. tubingensis nor A. acidus strains produced fumonisins, but 77% of A. niger strains did. None of the strains produced ochratoxin A. Ten selected fumonisin producing A. niger strains were further able to produce fumonisin B(2) and fumonisin B(4) on grapes in the range 171-7841 microg fumonisin B(2)/kg and 14-1157 microg fumonisin B(4)/kg. Four selected strains were able to produce fumonisin B(2) (5-6476 microg/kg) and fumonisin B(4) (12-672 microg/kg) on raisins. PMID:20014861

Mogensen, Jesper M; Frisvad, Jens C; Thrane, Ulf; Nielsen, Kristian F

2010-01-27

59

Production of l -asparaginase, an anticancer agent, from Aspergillus niger using agricultural waste in solid state fermentation  

Microsoft Academic Search

This article reports the production of high levels of l-asparaginase from a new isolate of Aspergillus niger in solid state fermentation (SSF) using agrowastes from three leguminous crops (bran of Cajanus cajan, Phaseolus mungo, and Glycine max). When used as the sole source for growth in SSF, bran of G. max showed maximum enzyme production followed by that of P.

Abha Mishra

2006-01-01

60

Recombinant bacterial hemoglobin alters metabolism of Aspergillus niger.  

PubMed

The filamentous fungus Aspergillus niger is used extensively for the production of enzymes and organic acids. A major problem in industrial fermentations with this fungus is to ensure sufficient supply of oxygen required for respiratory metabolism of the fungus. In case of oxygen limitation, the fungus will produce various by-products like organic acids and polyols. In order to circumvent this problem we here study the effects of the expression of a bacterial hemoglobin protein on the metabolism of A. niger. We integrated the vgb gene from Vitreoscilla sp. into the genome at the pyrA locus behind the strong gpdA promoter from Aspergillus nidulans. Analysis of secreted metabolites, oxygen uptake, CO(2) evolution and biomass formation points towards a relief of stress in the mutant expressing VHB when it is exposed to oxygen limitation. Our findings therefore point to an interesting strategy to attenuate unwanted side effects resulting from oxygen limitation during industrial fermentations with A. niger. PMID:18694843

Hofmann, Gerald; Diano, Audrey; Nielsen, Jens

2008-07-24

61

Comparative studies on citric acid production by Aspergillus niger and Candida lipolytica using molasses and glucose  

Microsoft Academic Search

Citric acid production by Aspergillus niger NCIM 548 and Candida lipolytica NCIM 3472 has been studied in shake culture using glucose and molasses as carbon sources. Methanol addition (3% v\\/v) at 40 h of fermentation enhanced the production of citric acid by Aspergillus niger whereas a reduction in citric acid production by Candida lipolytica was observed with addition of methanol.

M. Pazouki; P. A. Felse; J. Sinha; T. Panda

2000-01-01

62

Mannitol Is Required for Stress Tolerance in Aspergillus niger Conidiospores  

PubMed Central

d-Mannitol is the predominant carbon compound in conidiospores of the filamentous fungus Aspergillus niger and makes up 10 to 15% of the dry weight. A number of physiological functions have been ascribed to mannitol, including serving as a reserve carbon source, as an antioxidant, and to store reducing power. In this study, we cloned and characterized the A. niger mpdA gene, which encodes mannitol 1-phosphate dehydrogenase (MPD), the first enzyme in the mannitol biosynthesis pathway. The mpdA promoter contains putative binding sites for the development-specific transcription factors BRLA and ABAA. Furthermore, increased expression of mpdA in sporulating mycelium suggests that mannitol biosynthesis is, to a certain extent, developmentally regulated in A. niger. Inactivation of mpdA abolished mannitol biosynthesis in growing mycelium and reduced the mannitol level in conidiospores to 30% that in the wild type, indicating that MPD and mannitol 1-phosphate phosphatase form the major metabolic pathway for mannitol biosynthesis in A. niger. The viability of spores after prolonged storage and germination kinetics were normal in an mpdA null mutant, indicating that mannitol does not play an essential role as a reserve carbon source in A. niger conidia. However, conidiospores of a ?mpdA strain were extremely sensitive to a variety of stress conditions, including high temperature, oxidative stress and, to a lesser extent, freezing and lyophilization. Since mannitol supplied in the medium during sporulation repaired this deficiency, mannitol appears to be essential for the protection of A. niger spores against cell damage under these stress conditions.

Ruijter, George J. G.; Bax, Maarten; Patel, Hema; Flitter, Simon J.; van de Vondervoort, Peter J. I.; de Vries, Ronald P.; vanKuyk, Patricia A.; Visser, Jaap

2003-01-01

63

Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose - Chitin Interactions  

PubMed Central

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.

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

2011-01-01

64

Aspergillus niger time to growth in dried tomatoes.  

PubMed

Individual and combined effects of aw and incorporation of selected concentrations of Mexican oregano essential oil on the time to growth (TTG) of Aspergillus niger intentionally inoculated into dried tomatoes were studied during storage at 25°C for 100 days. For aw 0.96, 1,000 ppm of Mexican oregano essential oil inhibited A. niger growth during 100 days, whereas 500 ppm were sufficient at aw 0.91 and 250 ppm for tomatoes with aw 0.78. A. niger growth was evident at different incubation times depending on tested tomato aw and concentration of essential oil; these data were utilized to model TTG. Regression analysis revealed good agreement between experimental and predicted data with a correlation coefficient higher than 0.98. Analysis of mold growth data through TTG models makes possible to include observations detected as no growth and can be utilized to predict mold time to growth for specific preservation factor combinations or to select preservation factor levels for an expected shelf-life based on A. niger growth. PMID:23587709

Gómez-Ramírez, C; Sosa-Morales, M E; Palou, E; López-Malo, A

2013-03-23

65

Mineral nutrition of Aspergillus niger for citric acid production  

Microsoft Academic Search

The mineral requirements of a strain ofAspergillus niger for the production of citric acid in a synthetic medium were studied. It was observed that K2HPO4 and MgSO4.7 H2O were required at concentrations of 0.1% and 0.02% respectively. The optimum level of each of the trace elements Fe, Mn and\\u000a Zn was 1.0 ?g\\/ml. NaCl and CaCl2 at lower concentrations had

A. K. Banik

1976-01-01

66

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

SciTech Connect

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.

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

1980-01-01

67

Cloning and Expression of Gumboro VP2 Antigen in Aspergillus niger  

PubMed Central

Background Infectious Bursal Disease Virus (IBDV) causes a highly immunosuppressive disease in chickens and is a pathogen of major economic importance to the poultry industry worldwide. The VP2 protein is the major host-protective immunogen of IBDV and has been considered as a potential subunit vaccine against the disease. VP2 coding sequence was cloned in an inducible fungal vector and the protein was expressed in Aspergillus niger (A. niger). Methods Aiming at a high level of expression, a multicopy AMA1-pyrG-based episomal construct driven by a strong inducible promoter, glaA, was prepared and used in transformation of A. niger pyrG-protoplasts. SDS-PAGE and western blot analysis was carried out to confirm the expression of the protein. Results A number of pyrG + positive transformants were isolated and the presence of expression cassette was confirmed. Western blot analysis of one of these recombinant strains using monospecific anti-VP2 antibodies demonstrated the successful expression of the protein. The recombinant protein was also detected by serum obtained from immunized chicken. Conclusion In the present study, we have generated a recombinant A. niger strain expressing VP2 protein intracellulary. This recombinant strain of A. niger may have potential applications in oral vaccination against IBDV in poultry industry.

Azizi, Mohammad; Yakhchali, Bagher; Ghamarian, Abdolreza; Enayati, Somayeh; Khodabandeh, Mahvash; Khalaj, Vahid

2013-01-01

68

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

NASA Astrophysics Data System (ADS)

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 ? 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.

Hemdan, R.; et al.

69

Chemical induction of silent biosynthetic pathway transcription in Aspergillus niger.  

PubMed

Manipulation of the fungal epigenome is hypothesized to be an effective method for accessing natural products from silent biosynthetic pathways. A library of epigenetic modifiers was tested using the fungus Aspergillus niger to determine the impact of small-molecule inhibitors on reversing the transcriptional suppression of biosynthetic genes involved in polyketide (PKS), non-ribosomal peptide (NRPS), and hybrid PKS-NRPS (HPN) production. Examination of expressed sequence tag libraries from A. niger demonstrated that >70% of its PKS-, NRPS-, and HPN-encoding gene clusters were transcriptionally suppressed under standard laboratory culture conditions. Using a chemical epigenetic methodology, we showed that treatment of A. niger with suberoylanilide hydroxamic acid and 5-azacytidine led to the transcriptional upregulation of many secondary-metabolite-encoding biosynthetic gene clusters. Chemical epigenetic modifiers exhibited positional biases for upregulating chromosomally distal gene clusters. In addition, a phylogenetic-based preference was noted in the upregulation of reducing clade I PKS gene clusters, while reducing clade IV PKS gene clusters were largely unaffected. Manipulating epigenetic features in fungi is a powerful method for accessing the products of silent biosynthetic pathways. Moreover, this approach can be readily incorporated into modern microbial screening operations. PMID:19521728

Fisch, K M; Gillaspy, A F; Gipson, M; Henrikson, J C; Hoover, A R; Jackson, L; Najar, F Z; Wägele, H; Cichewicz, R H

2009-06-12

70

Cellulase Production from Spent Lignocellulose Hydrolysates by Recombinant Aspergillus niger?  

PubMed Central

A recombinant Aspergillus niger strain expressing the Hypocrea jecorina endoglucanase Cel7B was grown on spent hydrolysates (stillage) from sugarcane bagasse and spruce wood. The spent hydrolysates served as excellent growth media for the Cel7B-producing strain, A. niger D15[egI], which displayed higher endoglucanase activities in the spent hydrolysates than in standard medium with a comparable monosaccharide content (e.g., 2,100 nkat/ml in spent bagasse hydrolysate compared to 480 nkat/ml in standard glucose-based medium). In addition, A. niger D15[egI] was also able to consume or convert other lignocellulose-derived compounds, such as acetic acid, furan aldehydes, and phenolic compounds, which are recognized as inhibitors of yeast during ethanolic fermentation. The results indicate that enzymes can be produced from the stillage stream as a high-value coproduct in second-generation bioethanol plants in a way that also facilitates recirculation of process water.

Alriksson, Bjorn; Rose, Shaunita H.; van Zyl, Willem H.; Sjode, Anders; Nilvebrant, Nils-Olof; Jonsson, Leif J.

2009-01-01

71

Effect of vanillin concentration, pH and incubation temperature on Aspergillus flavus , Aspergillus niger , Aspergillus ochraceus and Aspergillus parasiticus growth  

Microsoft Academic Search

The effects of incubation temperature (10–30°C), pH (3.0–4.0) and vanillin concentration (350–1200ppm) on the growth ofAspergillus flavus, Aspergillus niger, Aspergillus ochraceusandAspergillus parasiticuswere evaluated using potato–dextrose agar adjusted to water activity (aw) 0.98. The radial growth rates after a lag period followed zero-order kinetics with constants that varied from 0 (no growth) to 0.63mmh?1. The lag period depended on vanillin concentration,

A López-Malo; S. M Alzamora; A Argaiz

1997-01-01

72

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

PubMed Central

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.

Singh, Gavendra; Prakash, Soam

2012-01-01

73

Two different types of intervening sequences in the glucoamylase gene from Aspergillus niger.  

PubMed Central

One single glucoamylase gene could be identified in the chromosomal DNA of Aspergillus niger by Southern blot analysis. This glucoamylase gene was isolated from a genomic library of A. niger DNA. The glucoamylase gene is situated on a 2.5-kb EcoRI-EcoRV fragment and contains five intervening sequences in the coding region. One 169-bp intron is involved in differential mRNA processing leading to the two different glucoamylase enzymes G1 and G2; the other four introns are all very small ranging from 55 to 75 bp in length. One intron has a significant homology to the coding region which immediately follows, and it contains the internal conserved sequence TACTAAC, which is also found in yeast chromosomal gene introns, and is thought to participate in mRNA splicing. Two transcription initiation sites and a typical eukaryotic promoter region with TATAAT and CAAT boxes are located upstream from the gene. Images Fig. 3. Fig. 4.

Boel, E; Hansen, M T; Hjort, I; H?egh, I; Fiil, N P

1984-01-01

74

The Purification and Characterization of an Endo-Xylanase from Aspergillus Niger.  

National Technical Information Service (NTIS)

Development of a method for the purification and partial characterization of endoxylanase obtained from the fungus Aspergillus niger is reported. This xylanase hydrolyzes xylan, a component of the hemicellulose complex found in large amounts in cereal. He...

R. F. Angel

1979-01-01

75

Biotransformation of germacranolide from Onopordon leptolepies by Aspergillus niger.  

PubMed

Terpenes are present in the essential oils obtained from herbs and spices. They are produced by these plant species as a chemical defense mechanism against phytopathogenic microorganisms. Therefore, terpenes have attracted great attention in the food industry, e.g., they have been used in foods such as cheese as natural preservatives to prevent fungal growth. Herein, we describe the microbial transformation of onopordopicrin (1) by Aspergillus niger. Four product 11? H-dihydroonopordopicrin (2), 11? H-dihydroonopordopicrin (3), 3?-hydroxy-11? H-dihydroonopordopicrin (4), and 14-hydroxy-11? H-dihydroonopordopicrin (5) were obtained. Their structures were identified on the basis of chemical and spectroscopic data. All the four compounds were novel. PMID:22186324

Esmaeili, Akbar; Moazami, Nasrin; Rustaiyan, Abdolhossein

2012-01-01

76

Catalytical Properties of Free and Immobilized Aspergillus niger Tannase.  

PubMed

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. K(M) and V(max) values for free enzyme were very similar for both substrates. But, after immobilization, K(M) and V(max) 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

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

2011-09-12

77

Catalytical Properties of Free and Immobilized Aspergillus niger Tannase  

PubMed Central

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.

Flores-Maltos, Abril; Rodriguez-Duran, Luis V.; Renovato, Jacqueline; Contreras, Juan C.; Rodriguez, Raul; Aguilar, Cristobal N.

2011-01-01

78

New pathway for the biodegradation of indole in Aspergillus niger.  

PubMed Central

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 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.

Kamath, A V; Vaidyanathan, C S

1990-01-01

79

Effect of Maltose on Glucoamylase Formation by Aspergillus niger  

PubMed Central

Low levels of glucoamylase are produced when Aspergillus niger is grown on sorbitol, but substitution of the latter by glucose, maltose, or starch results in greater formation of glucoamylase as measured by enzymatic activity. Both glucoamylase I and glucoamylase II are formed in a yeast extract medium; however, glucoamylase I appears to be the only form produced when ammonium chloride is the nitrogen source. Maltose or isomaltose (1.4 × 10?4m), but no other disaccharides or monosaccharides, dextrins, dextrans, or starches, stimulated glucoamylase formation when added to mycelia pregrown on sorbitol-ammonium salts. The induction of glucoamylase by maltose was independent of sulfate concentration but showed a dependency on low pH and the absence of utilizable carbon sources.

Barton, Larry L.; Georgi, Carl E.; Lineback, David R.

1972-01-01

80

Frequency and Species Distribution of Gliotoxin-Producing Aspergillus Isolates Recovered from Patients at a Tertiary-Care Cancer Center  

Microsoft Academic Search

Aspergillus isolates (n 103) collected from cancer patients were screened to determine the taxonomic distribution and quantity of gliotoxin production. Gliotoxin was detected in 93% of Aspergillus fumigatus, 75% of A. niger, 25% of A. terreus, and 4% of A. flavus cultures. Gliotoxin concentrations were highest in cultures of A. fumigatus. Aspergillus fumigatus produces several secondary metabo- lites during invasive

Russell E. Lewis; Nathan P. Wiederhold; Michail S. Lionakis; Randall A. Prince; Dimitrios P. Kontoyiannis

2005-01-01

81

Selection of biochemical mutants of Aspergillus niger with enhanced extracellular ribonuclease production  

Microsoft Academic Search

Combined with u.v. irradiation and the nitrosoguanidine method, selection of biochemical mutants resistant to metabolic inhibitors (2-deoxy-D-glucose, antimycin A, sodium orthovanadate and sodium azide) was a very efficient method for improvement of ribonuclease production by Aspergillus niger. Resistance to sodium azide produced highest RNase production, greatest frequency of positive mutation and shortest sporulation time. The most active strain, Aspergillus niger

Ya-Hong Xiong; Jian-Zhong Liu; Hai-Yan Song; Li-Ping Weng; Liang-Nian Ji

2004-01-01

82

Mapping the polysaccharide degradation potential of Aspergillus niger  

PubMed Central

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.

2012-01-01

83

Characterization of the Kexin-Like Maturase of Aspergillus niger  

PubMed Central

Secreted yields of foreign proteins may be enhanced in filamentous fungi through the use of translational fusions in which the target protein is fused to an endogenous secreted carrier protein. The fused proteins are usually separated in vivo by cleavage of an engineered Kex2 endoprotease recognition site at the fusion junction. We have cloned the kexin-encoding gene of Aspergillus niger (kexB). We constructed strains that either overexpressed KexB or lacked a functional kexB gene. Kexin-specific activity doubled in membrane-protein fractions of the strain overexpressing KexB. In contrast, no kexin-specific activity was detected in the similar protein fractions of the kexB disruptant. Expression in this loss-of-function strain of a glucoamylase human interleukin-6 fusion protein with an engineered Kex2 dibasic cleavage site at the fusion junction resulted in secretion of unprocessed fusion protein. The results show that KexB is the endoproteolytic proprotein processing enzyme responsible for the processing of (engineered) dibasic cleavage sites in target proteins that are transported through the secretion pathway of A. niger.

Jalving, Ruud; van de Vondervoort, Peter J. I.; Visser, Jaap; Schaap, Peter J.

2000-01-01

84

Homologue expression of a ?-xylosidase from native Aspergillus niger.  

PubMed

Xylan constitutes the second most abundant source of renewable organic carbon on earth and is located in the cell walls of hardwood and softwood plants in the form of hemicellulose. Based on its availability, there is a growing interest in production of xylanolytic enzymes for industrial applications. ?-1,4-xylan xylosidase (EC 3.2.1.37) hydrolyses from the nonreducing end of xylooligosaccharides arising from endo-1,4-?-xylanase activity. This work reports the partial characterization of a purified ?-xylosidase from the native strain Aspergillus niger GS1 expressed by means of a fungal system. A gene encoding ?-xylosidase, xlnD, was successfully cloned from a native A. niger GS1 strain. The recombinant enzyme was expressed in A. niger AB4.1 under control of A. nidulans gpdA promoter and trpC terminator. ?-xylosidase was purified by affinity chromatography, with an apparent molecular weight of 90 kDa, and showed a maximum activity of 4,280 U mg protein(-1) at 70°C, pH 3.6. Half-life was 74 min at 70°C, activation energy was 58.9 kJ mol(-1), and at 50°C optimum stability was shown at pH 4.0-5.0. ?-xylosidase kept residual activity >83% in the presence of dithiothreitol (DTT), ?-mercaptoethanol, sodium dodecyl sulfate (SDS), ethylenediaminetetraacetate (EDTA), and Zn(2+). Production of a hemicellulolytic free xylosidase showed some advantages in applications, such as animal feed, enzymatic synthesis, and the fruit-juice industry where the presence of certain compounds, high temperatures, and acid media is unavoidable in the juice-making process. PMID:21116681

Amaro-Reyes, A; García-Almendárez, B E; Vázquez-Mandujano, D G; Amaya-Llano, S; Castaño-Tostado, E; Guevara-González, R G; Loera, O; Regalado, C

2010-11-30

85

Atypical regioselective biohydrolysis on steroidal oxiranes by Aspergillus niger whole cells: Some stereochemical features  

Microsoft Academic Search

5,6-Epoxycholestan-3?-ol derivatives were hydrolyzed in a diastereoconvergent manner by growing and resting cells of several strains of Aspergillus niger, particularly A. niger ATCC 11394. These strains displayed opposite regioselectivity toward each isomer in an ? and ? epoxide mixture, thus, the nucleophilic attack took place at the less substituted and the most substituted carbon atom on each diasteromer, respectively. These

Fabricio R. Bisogno; Alejandro A. Orden; Celeste Aguirre Pranzoni; Diego A. Cifuente; Oscar S. Giordano; Marcela Kurina Sanz

2007-01-01

86

Identification and characterization of starch and inulin modifying network of Aspergillus niger by functional genomics  

Microsoft Academic Search

Aspergillus niger produces a wide variety of carbohydrate hydrolytic enzymes which have potential applications in the baking, starch, textile, food and feed industries. The goal of this thesis is to unravel the molecular mechanisms of starch and inulin modifying network of A. niger, in order to improve the enzyme production and substrate utilization as well as to find novel enzyme

Xiao-Lian Yuan

2008-01-01

87

Optimization of Citric Acid Production from a New Strain and Mutant of Aspergillus niger Using Solid State Fermentation  

Microsoft Academic Search

A new strain of Aspergillus niger isolated from soil and its mutant were used for citric acid production from carob under solid-state fermentation conditions. The parental strain produced 30 g\\/kg citric acid, while the mutant G4, selected after four rounds of gamma ray irradiation, produced 60 g\\/kg. Maximum citric acid production was obtained after 7 days of incubation, as the

Faiez Alani; Murray Moo-Young; William Anderson; Zakaria Bataine

2007-01-01

88

Ellagic acid production by Aspergillus niger in solid state fermentation of pomegranate residues.  

PubMed

Two Aspergillus niger strains (GH1 and PSH) previously isolated from a semiarid region of Mexico were characterized for their effectiveness in converting pomegranate ellagitannins (ET) into ellagic acid (EA) in a solid state fermentation (SSF). Pomegranate seeds and husk were used as support for the SSF. Released EA was evaluated by liquid chromatography. Yields of 6.3 and 4.6 mg of EA per gram of dried pomegranate husk were obtained with A. niger GH1 and PSH, respectively. Total hydrolyzable polyphenols of pomegranate husk were degraded during the first 72 h of culture (71 and 61%, by GH1 and PSH strains, respectively). Tannin acyl hydrolase activity was not clearly associated with EA production. EA that accumulated in cultures of A. niger GH1 was remarkably pure after a simple extraction process. Pomegranate husk is a good support, and at the same time an excellent substrate in the production of high commercial interest metabolites like EA due the degradation of its ET content. PMID:18228068

Robledo, Armando; Aguilera-Carbó, Antonio; Rodriguez, Raúl; Martinez, José Luis; Garza, Yolanda; Aguilar, Cristobal N

2008-01-29

89

Evaluation of the catalase promoter for expressing the alkaline xylanase gene (alx) in Aspergillus niger.  

PubMed

Aspergillus niger represents a promising host for the expression of recombinant proteins, but only a few expression systems are available for this organism. In this study, the inducible catalase promoter (PcatR) from A. niger was characterized. For this, constructs were developed and checked for the expression of the alkaline xylanase gene transcriptionally fused under the cat R promoter. Two versions of the catalase (catR) promoter sequence from A. niger (P(cat300,) P(cat924)) were isolated and tested for their ability to drive expression of the alkaline xylanase (alx) gene. P(cat924) showed better efficiency (more than 10-fold increase in AlX activity compared to P(cat300)) under the optimized culture conditions. Induction of the catR promoter with 0.20% H(2)O(2) and 1.5% CaCO(3) in the culture medium, further increased expression of AlX 2.61- and 2.20-fold, respectively, clarifying its inducible nature. Specific induction or repression of the catR promoter provides the possibility for utilization of this promoter in heterologous protein production. PMID:22092890

Sharma, Ruchika; Katoch, Meenu; Govindappa, Nagraj; Srivastava, P S; Sastry, Kedarnath N; Qazi, Ghulam Nabi

2011-12-12

90

Antifungal effects of citronella oil against Aspergillus niger ATCC 16404.  

PubMed

Essential oils are aromatic oily liquids obtained from some aromatic plant materials. Certain essential oils such as citronella oil contain antifungal activity, but the antifungal effect is still unknown. In this study, we explored the antifungal effect of citronella oil with Aspergillus niger ATCC 16404. The antifungal activity of citronella oil on conidia of A. niger was determined by poisoned food technique, broth dilution method, and disc volatility method. Experimental results indicated that the citronella oil has strong antifungal activity: 0.125 (v/v) and 0.25 % (v/v) citronella oil inhibited the growth of 5?×?10? spore/ml conidia separately for 7 and 28 days while 0.5 % (v/v) citronella oil could completely kill the conidia of 5?×?10? spore/ml. Moreover, the fungicidal kinetic curves revealed that more than 90 % conidia (initial concentration is 5?×?10? spore/ml) were killed in all the treatments with 0.125 to 2 % citronella oil after 24 h. Furthermore, with increase of citronella oil concentration and treatment time, the antifungal activity was increased correspondingly. The 0.5 % (v/v) concentration of citronella oil was a threshold to kill the conidia thoroughly. The surviving conidia treated with 0.5 to 2 % citronella oil decreased by an order of magnitude every day, and no fungus survived after 10 days. With light microscope, scanning electron microscope, and transmission electron microscope, we found that citronella oil could lead to irreversible alteration of the hyphae and conidia. Based on our observation, we hypothesized that the citronella oil destroyed the cell wall of the A. niger hyphae, passed through the cell membrane, penetrated into the cytoplasm, and acted on the main organelles. Subsequently, the hyphae was collapsed and squashed due to large cytoplasm loss, and the organelles were severely destroyed. Similarly, citronella oil could lead to the rupture of hard cell wall and then act on the sporoplasm to kill the conidia. Nevertheless, the citronella oil provides a potential of being a safe and environmentally friendly fungicide in the future. PMID:23081773

Li, Wen-Ru; Shi, Qing-Shan; Ouyang, You-Sheng; Chen, Yi-Ben; Duan, Shun-Shan

2012-10-19

91

Efficacy of anidulafungin against Aspergillus niger in vitro and in vivo.  

PubMed

In this study, anidulafungin (AFG) showed high in vitro activity against 10 isolates of Aspergillus niger by broth microdilution and disk diffusion methods. The efficacy of AFG at 1, 5 and 10 mg/kg was tested against six of the isolates in a murine model of disseminated infection. AFG was able to reduce mortality, showing survival rates of 70-100%, 60-100% and 30-60% in mice treated with AFG at 10, 5 and 1 mg/kg, respectively. AFG also showed a dose-response efficacy in reducing tissue burden in kidneys and spleen. A parallel experiment demonstrated that administration of AFG did not reduce serum concentrations of galactomannan in mice. Histopathological studies confirmed the efficacy of AFG. PMID:21824751

Calvo, Enrique; Pastor, F Javier; Mayayo, Emilio; Guarro, Josep

2011-08-06

92

Review of secondary metabolites and mycotoxins from the Aspergillus niger group.  

PubMed

Filamentous fungi in the Aspergillus section Nigri (the black aspergilli) represent some of the most widespread food and feed contaminants known but they are also some of the most important workhorses used by the biotechnological industry. The Nigri section consists of six commonly found species (excluding A. aculeatus and its close relatives) from which currently 145 different secondary metabolites have been isolated and/or detected. From a human and animal safety point of view, the mycotoxins ochratoxin A (from A. carbonarius and less frequently A. niger) and fumonisin B(2) (from A. niger) are currently the most problematic compounds. Especially in foods and feeds such as coffee, nuts, dried fruits, and grape-based products where fumonisin-producing fusaria are not a problem, fumonisins pose a risk. Moreover, compounds such as malformins, naptho-gamma-pyrones, and bicoumarins (kotanins) call for monitoring in food, feed, and biotechnology products as well as for a better toxicological evaluation, since they are often produced in large amounts by the black aspergilli. For chemical differentiation/identification of the less toxic species the diketopiperazine asperazine can be used as a positive marker since it is consistently produced by A. tubingensis (177 of 177 strains tested) and A. acidus (47 of 47 strains tested) but never by A. niger (140 strains tested). Naptho-gamma-pyrones are the compounds produced in the highest quantities and are produced by all six common species in the group (A. niger 134 of 140; A. tubingensis 169 of 177; A. acidus 44 of 47; A. carbonarius 40 of 40, A. brasiliensis 18 of 18; and A. ibericus three of three). PMID:19756540

Nielsen, Kristian Fog; Mogensen, Jesper Mølgaard; Johansen, Maria; Larsen, Thomas O; Frisvad, Jens Christian

2009-09-16

93

A two-step bioconversion process for vanillin production from ferulic acid combining Aspergillus niger and Pycnoporus cinnabarinus  

Microsoft Academic Search

A two-step bioconversion process of ferulic acid to vanillin was elaborated combining two filamentous fungi, Aspergillus niger and Pycnoporus cinnabarinus. In the first step, A. niger transformed ferulic acid to vanillic acid and in the second step vanillic acid was reduced to vanillin by P. cinnabarinus. Ferulic acid metabolism by A. niger occurred essentially via the propenoic chain degradation to

Laurence Lesage-Meessen; Michel Delattre; Mireille Haon; Jean-François Thibault; Benoit Colonna Ceccaldi; Pascal Brunerie; Marcel Asther

1996-01-01

94

Structure-activity relationship of citrus polymethoxylated flavones and their inhibitory effects on Aspergillus niger.  

PubMed

Citrus peels are rich in polymethoxylated flavones (PMFs) and are potential sources of natural preservatives. Six PMFs extracts, isolated and purified from the peels of three mandarins (Citrus reticulata) and three sweet oranges (Citrus sinensis), were identified and quantitated. Their inhibitory effects on Aspergillus niger were evaluated using a microbroth dilution assay. The Red tangerine variety exhibited the greatest antifungal activity (MIC = 0.2 mg/mL), while Jincheng showed the lowest activity (MIC = 1.8 mg/mL). An analysis of principal components was applied to the results in order to elucidate the structure-activity relationships of the citrus PMFs. The structure-activity relationship analysis revealed that, for good inhibitory effect, the 5-OH, 3-OCH?, and 8-OCH? functionalities were essential, while the presence of 3-OH and 3'-OCH? greatly reduced inhibition. The findings of this study provide important information for the exploitation and utilization of citrus PMFs as natural biopreservatives. PMID:22500738

Liu, Li; Xu, Xiaoyun; Cheng, Dan; Yao, Xiaolin; Pan, Siyi

2012-04-20

95

Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88  

Microsoft Academic Search

The filamentous fungus Aspergillus niger is widely exploited by the fermentation industry for the production of enzymes and organic acids, particularly citric acid. We sequenced the 33.9-megabase genome of A. niger CBS 513.88, the ancestor of currently used enzyme production strains. A high level of synteny was observed with other aspergilli sequenced. Strong function predictions were made for 6,506 of

Herman J Pel; Johannes H de Winde; David B Archer; Paul S Dyer; Gerald Hofmann; Peter J Schaap; Geoffrey Turner; Ronald P de Vries; Richard Albang; Kaj Albermann; Mikael R Andersen; Jannick D Bendtsen; Jacques A E Benen; Marco van den Berg; Stefaan Breestraat; Mark X Caddick; Roland Contreras; Michael Cornell; Pedro M Coutinho; Etienne G J Danchin; Alfons J M Debets; Peter Dekker; Piet W M van Dijck; Alard van Dijk; Lubbert Dijkhuizen; Arnold J M Driessen; Christophe d'Enfert; Steven Geysens; Coenie Goosen; Gert S P Groot; Piet W J de Groot; Thomas Guillemette; Bernard Henrissat; Marga Herweijer; Johannes P T W van den Hombergh; Cees A M J J van den Hondel; Rene T J M van der Heijden; Rachel M van der Kaaij; Frans M Klis; Harrie J Kools; Christian P Kubicek; Patricia A van Kuyk; Jürgen Lauber; Xin Lu; Marc J E C van der Maarel; Rogier Meulenberg; Hildegard Menke; Martin A Mortimer; Jens Nielsen; Stephen G Oliver; Maurien Olsthoorn; Karoly Pal; Arthur F J Ram; Ursula Rinas; Johannes A Roubos; Cees M J Sagt; Monika Schmoll; Jibin Sun; David Ussery; Janos Varga; Wouter Vervecken; Holger Wedler; Han A B Wösten; An-Ping Zeng; Albert J J van Ooyen; Jaap Visser; Hein Stam

2007-01-01

96

Biochemical studies of citric acid production and accumulation by Aspergillus niger mutants  

Microsoft Academic Search

The biochemical rationale for the inhibition of citric acid fermentation by Aspergillus niger in the presence of Mn2+ ions has been investigated using high citric acid-yielding, Mn2+ ion-sensitive as well as Mn2+ ion-tolerant mutant strains of A. niger. In the presence of Mn2+ (1.5 mg\\/l), citric acid production by the Mn2+ ion-sensitive strain (KCU 520) was reduced by about 75%

Sanjay Gupta; Chandra B. Sharma

2002-01-01

97

Ellagic Acid Production from Biodegradation of Creosote Bush Ellagitannins by Aspergillus niger in Solid State Culture  

Microsoft Academic Search

The ability of Aspergillus niger GH1 in converting creosote bush ellagitannins into ellagic acid (EA) was evaluated in solid state culture. Creosote bush\\u000a leaves were used to extract the ellagitannins fraction, which was impregnated in polyurethane foam used as support of solid\\u000a state culture. Ellagitannins content, EA accumulation, and the related enzymatic activities were evaluated. A. niger GH1 was able

Antonio Aguilera-Carbo; Juan S. Hernández; Christopher Augur; Lilia A. Prado-Barragan; Ernesto Favela-Torres; Cristóbal N. Aguilar

2009-01-01

98

Optimization of Aspergillus niger Fermentation for the Production of Glucose Oxidase  

Microsoft Academic Search

A number of nutritional factors influencing glucose oxidase (EC 1.1.3.4) production by Aspergillus niger NCIM 545 were studied. The synthesis of glucose oxidase by A. niger was investigated in two steps using submerged fermentation at 30?±?2 °C and 180 rpm for 96 h. Primarily, nutritional components\\u000a were selected by one-factor-at-a-time method, and the significance of each component with respect to glucose oxidase

Sandip B. Bankar; Mahesh V. Bule; Rekha S. Singhal; Laxmi Ananthanarayan

2009-01-01

99

Direct production of citric acid from raw starch by Aspergillus niger  

Microsoft Academic Search

The present study deals with the direct production of citric acid from raw starch by Aspergillus niger. Shake flask and semi solid culture methods were compared using A. niger GCB-47 (parental strain) and GCMC-7 (mutant strain). When cultivated in shaking culture with 150 g\\/l soluble starch as a carbon source, the mutant strain GCMC-7 produced 69.5 g\\/l citric acid, which

Ikram-Ul Haq; Sikander Ali; Javed Iqbal

2003-01-01

100

Gene deletion of cytosolic ATP: citrate lyase leads to altered organic acid production in Aspergillus niger  

Microsoft Academic Search

With the availability of the genome sequence of the filamentous fungus Aspergillus niger, the use of targeted genetic modifications has become feasible. This, together with the fact that A. niger is well established industrially, makes this fungus an attractive micro-organism for creating a cell factory platform for\\u000a production of chemicals. Using molecular biology techniques, this study focused on metabolic engineering

Susan Meijer; Michael Lynge Nielsen; Lisbeth Olsson; Jens Nielsen

2009-01-01

101

Beneficiation of iron ore slime using Aspergillus niger and Bacillus circulans.  

PubMed

Studies were carried out on the removal of alumina from iron ore slime containing (%) Fe(2)O(3) 75.7, Al(2)O(3) 9.95, SiO(2) 6.1, Fe (total) 52.94 with the help of Bacillus circulans and Aspergillus niger. B. circulans and A. niger showed 39% and 38% alumina removal after six and 15 days of in situ leaching at 10% pulp density, respectively. Culture filtrate leaching with A. niger removed 20% alumina at 2% pulp density with 13 day old culture filtrate. B. circulans was more efficient than A. niger for selective removal of alumina. In case of A. niger in situ leaching rather than culture filtrate leaching was found to be more effective. PMID:16531043

Pradhan, N; Das, B; Gahan, C S; Kar, R N; Sukla, L B

2006-03-13

102

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

PubMed

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 56°C 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

Esbelin, Julia; Mallea, Sabine; J Ram, Arthur F; Carlin, Frédéric

2013-01-29

103

Secretion, purification, and characterisation of barley ? -amylase produced by heterologous gene expression in Aspergillus niger  

Microsoft Academic Search

Efficient production of recombinant barley ?-amylase has been achieved in Aspergillus niger. The cDNA encoding ?-amylase isozyme 1 (AMY1) and its signal peptide was placed under the control of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter and the A. nidulans trpC gene terminator. Secretion yields up to 60?mg\\/l were obtained in media optimised for ?-amylase activity and low protease\\u000a activity.

N. Juge; B. Svensson; G. Williamson

1998-01-01

104

A novel tannase from the xerophilic fungus Aspergillus niger GH1.  

PubMed

Aspergillus niger GH1 previously isolated and identified by our group as a wild tannase producer was grown under solid-state (SSC) and submerged culture (SmC) conditions to select the enzyme production system. For tannase purification, extracellular tannase was produced under SSC using polyurethane foam as the inert support. Tannase was purified to apparent homogeneity by ultrafiltration, anion-exchange chromatography, and gel filtration that led to a purified enzyme with a specific activity of 238.14 IU/mg protein with a final yield of 0.3% and a purification fold of 46. Three bands were found on the SDS-PAG with molecular masses of 50, 75, and 100 kDa. PI of 3.5 and 7.1% Nglycosylation were noted. Temperature and pH optima were 60 degrees and 6.0 [methyl 3,4,5-trihydroxybenzoate (MTB) as substrate], respectively. Tannase was found with a KM value of 0.41 x 10-4 M and the value of Vmax was 11.03 micromoL/min at 60 degrees for MTB. Effects of several metal salts, solvents, surfactants, and typical enzyme inhibitors on tannase activity were evaluated to establish the novelty of the enzyme. Finally, the tannase from A. niger GH1 was significantly inhibited by PMSF (phenylmethylsulfonyl fluoride), and therefore, it is possible to consider the presence of a serine or cysteine residue in the catalytic site. PMID:19809257

Mata-Gomez, Marco; Rodriguez, Luis V; Ramos, Erika L; Renovato, Jacqueline; Cruz-Hernandez, Mario A; Rodriguez, Raul; Contreras, Juan; Aguilar, Cristobal N

2009-09-01

105

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

Microsoft Academic Search

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

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

2009-01-01

106

Molecular detection of ochratoxigenic Aspergillus species isolated from coffee beans in Saudi Arabia.  

PubMed

Ten fungal isolates from coffee beans were morphologically identified as Aspergillus niger, A. ochraceus and A. carbonari-us (N = 5, 3, and 2, respectively). Only one isolate, morphologically identified as A. niger, was unable to produce ochratoxin A (OTA). This may be a new species in the Aspergillus section Nigri. OTA levels in all the other isolates were above the limit of detection (0.15 mg/kg). Based on microsatellite-primed PCR (MP-PCR) profiles, using three microsatellite primers, three main groups were obtained by UPGMA cluster analysis: A. niger, A. ochraceus and A. carbonarius. A clear-cut association was found between the MP-PCR genotype and the ability to produce OTA. Using the primer pairs OCRA1/OCRA2, a single fragment of about 400 bp was amplified only when genomic DNA from the A. ochraceus isolates was used. PMID:21128209

Moslem, M A; Mashraqi, A; Abd-Elsalam, K A; Bahkali, A H; Elnagaer, M A

2010-11-23

107

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...

108

Systemic analysis of the response of Aspergillus niger to ambient pH  

Microsoft Academic Search

ABSTRACT: BACKGROUND: The filamentous fungus Aspergillus niger is an exceptionally efficient producer of organic acids, which is one of the reasons for its relevance to industrial processes and commercial importance. While it is known that the mechanisms regulating this production are tied to the levels of ambient pH, the reasons and mechanisms for this are poorly understood. METHODS: To cast

Mikael R Andersen; Linda Lehmann; Jens Nielsen

2009-01-01

109

The effect of the sugar source on citric acid production by Aspergillus niger  

Microsoft Academic Search

Under otherwise identical fermentation conditions, the sugar source has been shown to have a marked effect on citric acid production by Aspergillus niger. Sucrose was the most favourable source, followed by glucose and fructose and then lactose. No citric acid was produced from galactose. Strong relationships were observed between citric acid production and the activities of certain enzymes in myccelial

M. Hossain; J. D. Brooks; I. S. Maddox

1984-01-01

110

Bioleaching of zinc and nickel from silicates using Aspergillus niger cultures  

Microsoft Academic Search

In this work, we investigated the role of bacteria from the genera Bacillus and Pseudomonas and fungi from the genera Aspergillus and Penicillium in the leaching process of two different silicates (calamine and garnierite). Since the results obtained with A. niger were better than those with different bacteria, a more detailed investigation of the leaching process with this microorganism was

I. M Castro; J. L. R Fietto; R. X Vieira; M. J. M Trópia; L. M. M Campos; E. B Paniago; R. L Brandão

2000-01-01

111

Xylanase production in solid state fermentation by Aspergillus niger mutant using statistical experimental designs  

Microsoft Academic Search

. The initial moisture content, cultivation time, inoculum size and concentration of basal medium were optimized in solid state fermentation (SSF) for the production of xylanase by an Aspergillus niger mutant using statistical experimental designs. The cultivation time and concentration of basal medium were the most important factors affecting xylanase activity. An inoculum size of 5쎹 spores\\/g, initial moisture content

Y. S. Park; S. W. Kang; J. S. Lee; S. I. Hong; S. W. Kim

2002-01-01

112

Biosorption and solubilization of copper oxychloride fungicide by Aspergillus niger and the influence of calcium  

Microsoft Academic Search

The biosorption of copper oxychloride fungicide particulates(~1 µm diameter), at concentrations ranging from 25 to 500 ppm active ingredient (ai), by pelleted mycelium of Aspergillus niger grown on Czapek Dox medium was evaluated. The concentration of the fungicide adsorbed to the mycelium, remaining suspended or solubilized in the medium, was determined by analysis of its copper content (CuF)using atomic absorption

Mohammed M. Gharieb

2002-01-01

113

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 ...

114

Morphological patterns of Aspergillus niger biofilms and pellets related to lignocellulolytic enzyme productivities  

Microsoft Academic Search

Aims: To study the morphological patterns of Aspergillus niger during biofilm formation on polyester cloth by using cryo-scanning electron microscopy rela- ted to lignocellulolytic enzyme productivity. Methods and Results: Biofilm and pellet samples obtained from flask cultures were examined at )80? C in a LEO PV scanning electron microscope. Spore adhesion depends on both its rough surface and adhesive substances

G. K. Villena; M. Gutiérrez-Correa

2007-01-01

115

Exploiting proteomic data for genome annotation and gene model validation in Aspergillus niger  

Microsoft Academic Search

BACKGROUND: Proteomic data is a potentially rich, but arguably unexploited, data source for genome annotation. Peptide identifications from tandem mass spectrometry provide prima facie evidence for gene predictions and can discriminate over a set of candidate gene models. Here we apply this to the recently sequenced Aspergillus niger fungal genome from the Joint Genome Institutes (JGI) and another predicted protein

James C Wright; Deana Sugden; Sue Francis-McIntyre; Isabel Riba-Garcia; Simon J Gaskell; Igor V Grigoriev; Scott E Baker; Robert J Beynon; Simon J Hubbard

2009-01-01

116

Attempts at improving citric acid fermentation by Aspergillus niger in beet-molasses medium  

Microsoft Academic Search

Natural oils with high unsaturated fatty acids content when added at concentrations of 2% and 4% (v\\/v) to beet molasses (BM) medium caused a considerable increase in citric acid yield from Aspergillus niger. The fermentation capacities were also examined for production of citric acid using BM-oil media under different fermentation conditions. Maximum citric acid yield was achieved in surface culture

Nehad Z. Adham

2002-01-01

117

Improvement of citric acid production by Aspergillus niger with addition of phytate to beet molasses  

Microsoft Academic Search

Phytate is an important plant constituent and can be found in the seeds of cereals and legumes. Phytic acid has 12 replaceable protons in the phytic molecule, giving it the ability to complex with multivalent cations. In this study, the phytate was used as an additive to enhance citric acid production by Aspergillus niger from an untreated beet molasses. The

Jianlong Wang

1998-01-01

118

Citric acid production from beet molasses by cell recycle of Aspergillus niger  

Microsoft Academic Search

Summary Production of citric acid from beet molasses at a varying pH profile using cell recycle ofAspergillus niger was investigated. Best results in terms of citric acid concentration, yield, productivity and specific citric acid productivity were obtained with a substrate pH of 3.0.

T. Roukas; E. Alichanidis

1991-01-01

119

Water and water activity in the solid state fermentation of cassava starch by Aspergillus niger  

Microsoft Academic Search

During the solid state fermentation (SSF) of cassava starch by Aspergillus niger estimations were made of total water, consumed water and the residual water remaining in small quantities after 23 h. A theoretical calculation based on the Ross equation showed that the water activity (aw) of the substrate decreased to 0.85 towards the end of the culture. Such low values

Eric Oriol; Maurice Raimbault; Sevastianos Roussos; Gustavo Viniegra-Gonzales

1988-01-01

120

Ethanol production from Jerusalem artichoke tubers by Aspergillus niger and Saccharomyces cerevisiae  

Microsoft Academic Search

Simultaneous saccharification and fermentation of Jerusalem artichoke tubers were conducted batchwise at 30°C using Aspergillus niger 817 and Saccharomyces cerevisiae 1200. Ethanol concentrations obtained were 10.4% (v\\/v) from the ground tubers after 15 h, 15.0% from the juice concentrate after 72 h, and 20.1% from the flour after 120 h.

Toyohiko Nakamura; Yasuko Ogata; Shigeyuki Hamada; Kazuyoshi Ohta

1996-01-01

121

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

PubMed

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

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

2010-01-25

122

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

PubMed Central

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.

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

1985-01-01

123

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

Microsoft Academic Search

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

Xin Lu; Jibin Sun; Manfred Nimtz; Josef Wissing; An-Ping Zeng; Ursula Rinas

2010-01-01

124

Optimization of Trace Metals Concentration on Citric Acid Production by Aspergillus niger NRRL 2001  

Microsoft Academic Search

Citric acid is nowadays produced by submerged fermentation of Aspergillus niger. The process yield depends on the composition of the medium, as well as on the microorganism strain. In this work, the effect\\u000a of Fe+3, Zn+2, and Mn+2 on citric acid production by A. niger NRRL 2001 is presented. The culture medium composition was glucose (120 g\\/L) KH2PO4 (1.0 g\\/L); K2HPO4 (1.0 g\\/L),

A. A. Guilherme; G. A. S. Pinto; S. Rodrigues

2008-01-01

125

Successful boric acid treatment of Aspergillus niger infection in an exenterated orbit.  

PubMed

Aspergillus niger infection of an exenterated orbit is a very rare occurrence. Treatment includes extensive surgical debridement with socket lavage with 0.6% hydrogen peroxide, oral itraconazole, and local amphotericin B. We describe a case of A. niger infection in an exenterated orbit, unresponsive to local amphotericin B, that was successfully treated with weekly boric acid irrigation. We conclude that local and conservative therapy with 2.5% boric acid solution in 70% ethanol is a useful option in the management of these cases. PMID:18209660

Aviñó-Martínez, Juan A; España-Gregori, Enrique; Peris-Martínez, Cristina P; Blanes, Marino

126

Growth inhibition and morphological alterations of Aspergillus niger by essential oils from Thymus eriocalyx and Thymus x-porlock  

Microsoft Academic Search

The antifungal effects of essential oils from Thymus eriocalyx and Thymus x-porlock were studied with special reference to the mechanism of inhibition of Aspergillus niger growth at ultrastructural level. Minimal inhibitory (MIC), minimal fungicidal (MFC) concentrations, and fungicidal kinetics of the oils were determined. Transmission electron microscopy (TEM) of A. niger exposed to MIC levels of the oils showed irreversible

Iraj Rasooli; Mohammad Bagher Rezaei; Abdolamir Allameh

2006-01-01

127

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

Microsoft Academic Search

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

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

2011-01-01

128

Properties of a major ?-glucosidase-BGL1 from Aspergillus niger NII08121 expressed differentially in response to carbon sources  

Microsoft Academic Search

Aspergillus niger NII-08121\\/MTCC 7956 exhibited differences in expression of ?-glucosidase (BGL) in response to carbon sources provided in the medium. Activity staining with methyl umbelliferyl ?-d-glucopyranoside (MUG) indicated that four different isoforms of BGL were expressed when A. niger was grown under submerged fermentation with either lactose or cellulose, whereas only two were expressed when wheat bran or rice straw

Reeta Rani Singhania; Rajeev Kumar Sukumaran; Kuni Parambil Rajasree; Abraham Mathew; Lalithadevi Gottumukkala; Ashok Pandey

2011-01-01

129

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

Microsoft Academic Search

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

Hanem Awad; Gerrit Beldman; Berg van den J. A

2006-01-01

130

Regulation of pentose utilisation by AraR, but not XlnR, differs in Aspergillus nidulans and Aspergillus niger.  

PubMed

Filamentous fungi are important producers of plant polysaccharide degrading enzymes that are used in many industrial applications. These enzymes are produced by the fungus to liberate monomeric sugars that are used as carbon source. Two of the main components of plant polysaccharides are L-arabinose and D-xylose, which are metabolized through the pentose catabolic pathway (PCP) in these fungi. In Aspergillus niger, the regulation of pentose release from polysaccharides and the PCP involves the transcriptional activators AraR and XlnR, which are also present in other Aspergilli such as Aspergillus nidulans. The comparative analysis revealed that the regulation of the PCP by AraR differs in A. nidulans and A. niger, whereas the regulation of the PCP by XlnR was similar in both species. This was demonstrated by the growth differences on L-arabinose between disruptant strains for araR and xlnR in A. nidulans and A. niger. In addition, the expression profiles of genes encoding L-arabinose reductase (larA), L-arabitol dehydrogenase (ladA) and xylitol dehydrogenase (xdhA) differed in these strains. This data suggests evolutionary changes in these two species that affect pentose utilisation. This study also implies that manipulating regulatory systems to improve the production of polysaccharide degrading enzymes, may give different results in different industrial fungi. PMID:21484208

Battaglia, Evy; Hansen, Sara Fasmer; Leendertse, Anne; Madrid, Susan; Mulder, Harm; Nikolaev, Igor; de Vries, Ronald P

2011-04-12

131

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

PubMed

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

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

2012-06-01

132

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

PubMed Central

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.

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

2012-01-01

133

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

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 µg/ml for Aspergillus niger and 2,000 µg/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.

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

2013-01-01

134

Production of ascorbic acid glucoside by alginate-entrapped mycelia of Aspergillus niger  

Microsoft Academic Search

The mycelia of Aspergillus niger, cultivated in a medium containing 45 g l?1 maltose, 66 g l?1 yeast extract, and 5 g l?1 K2HPO4 at 30°C and 200 rpm, were used as a biocatalyst in the glucosylation of ascorbic acid. Free mycelia from 3-day-old culture,\\u000a when used in a 6-h reaction with maltose as the acyl donor, gave 16.07 g l?1 ascorbic acid glucoside corresponding

Hsin-Ju Hsieh; Kai-Yu Tung; Giridhar R. Nair; I-Ming Chu; Wen-Teng Wu

2007-01-01

135

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

Microsoft Academic Search

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,

Youssuf A. M. H Gherbawy

1998-01-01

136

Overproduction of the Aspergillus niger feruloyl esterase for pulp bleaching application  

Microsoft Academic Search

A well-known industrial fungus for enzyme production, Aspergillus niger, was selected to produce the feruloyl esterase FAEA by homologous overexpression for pulp bleaching application. The gpd gene promoter was used to drive FAEA expression. Changing the nature and concentration of the carbon source nature (maltose to glucose; from 2.5 to 60 g l -1), improved FAEA activity 24.5-fold and a yield of

E. Record; M. Asther; C. Sigoillot; S. Pagès; P. J. Punt; M. Delattre; M. Haon; C. A. M. J. J. van den Hondel; J.-C. Sigoillot; L. Lesage-Meessen

2003-01-01

137

ENHANCEMENT OF INVERTASE PRODUCTION BY ASPERGILLUS NIGER OZ–3 USING LOW – INTENSITY STATIC MAGNETIC FIELDS  

Microsoft Academic Search

The aim of the present study was to investigate the effect of low-intensity static magnetic fields (SMFs) on invertase activity and growth on different newly identified moulds. The most positive effect of SMFs on invertase activity and growth was observed forAspergillus niger OZ–3. The submerged production of invertase was performed with the spores obtained at the different exposure times (120,

Mesut Taskin; Nevzat Esim; Mucip Genisel; Serkan Ortucu; Ismet Hasenekoglu; Ozden Canli; Serkan Erdal

2012-01-01

138

Production of inulinase by mixed culture of Aspergillus niger and Kluyveromyces marxianus  

Microsoft Academic Search

Inulinase activity produced by a mixed culture of Aspergillus niger and Kluyveromyces marxianus growing on Jerusalem artichoke powder was investigated. Inulinase produced by this mixed culture had a higher invertase-type activity than inulinase from respective monocultures. When hydrolysis was carried out at 50°C with Jerusalem artichoke exctract (total sugar 16% w\\/v) at pH 5.0, 90% hydrolysis was achieved after 4

Gaye Öngen-Baysal; S. Sukan

1996-01-01

139

Expression of the Caldariomyces fumago Chloroperoxidase in Aspergillus niger and Characterization of the Recombinant Enzyme  

Microsoft Academic Search

The Caldariomyces fumago chloroperoxidase was suc- cessfully expressed in Aspergillus niger. The recombi- nant enzyme was produced in the culture medium as an active protein and could be purified by a three-step purification procedure. The catalytic behavior of recom- binant chloroperoxidase (rCPO) was studied and com- pared with that of native CPO. The specific chlorination activity (47 units\\/nmol) of rCPO

Ana Conesa; Fred van de Velde; Fred van Rantwijk; Roger A. Sheldon; Cees A. M. J. J. van den Hondel; Peter J. Punt

2001-01-01

140

Characterization of nigerlysin ©, hemolysin produced by Aspergillus niger, and effect on mouse neuronal cells in vitro  

Microsoft Academic Search

Aspergillus niger produced a proteinaceous hemolysin, nigerlysin © when incubated on sheep's blood agar (SBA) at both 23 and 37°C. Nigerlysin was purified from tryptic soy broth (TSB) culture filtrate and found to have a molecular weight of approximately 72kDa, with an isoelectric point of 3.45. Nigerlysin is heat stable up to 65°C but unstable at 75°C when incubated for

Maura Donohue; Wei Wei; Jinfang Wu; Nasser H. Zawia; Nicholas Hud; Victor De Jesus; Detlef Schmechel; Justin M. Hettick; Donald H. Beezhold; Stephen Vesper

2006-01-01

141

Catalytic properties of mycelium-bound lipases from Aspergillus niger MYA 135  

Microsoft Academic Search

A constitutive level of a mycelium-bound lipolytic activity from Aspergillus niger MYA 135 was strongly increased by 97% in medium supplemented with 2% olive oil. The constitutive lipase showed an optimal\\u000a activity in the pH range of 3.0–6.5, while the mycelium-bound lipase activity produced in the presence of olive oil had two\\u000a pH optima at pH 4 and 7. Interestingly, both

Cintia M. Romero; Mario D. Baigori; Licia M. Pera

2007-01-01

142

Solution structure of the granular starch binding domain of Aspergillus niger glucoamylase bound to ?-cyclodextrin  

Microsoft Academic Search

Background: Carbohydrate-binding domains are usually small and physically separate from the catalytic domains of hydrolytic enzymes. Glucoamylase 1 (G1) from Aspergillus niger, an enzyme used widely in the food and brewing industries, contains a granular starch binding domain (SBD) which is separated from the catalytic domain by a semi-rigid linker. The aim of this study was to determine how the

Kay Sorimachi; Marie-Françoise Le Gal-Coëffet; Gary Williamson; David B Archer; Michael P Williamson

1997-01-01

143

Lipase production from Aspergillus niger by solid-state fermentation using gingelly oil cake  

Microsoft Academic Search

Cultural conditions for the production of lipase by Aspergillus niger strain MTCC 2594 by solid-state fermentation using gingelly oil cake were standardized. A lipase activity of 363·6 U\\/g of dry substrate was obtained at 72 h under optimum conditions. Addition of various nitrogen sources, carbohydrates and inducers to the substrate was found to be ineffective. The enzyme was optimally active

N. R. Kamini; J. G. S. Mala; R. Puvanakrishnan

1998-01-01

144

Cellulase production by Aspergillus niger in biofilm, solid-state, and submerged fermentations  

Microsoft Academic Search

Cellulase production by Aspergillus niger was compared in three different culture systems: biofilm, solid-state, and submerged fermentation. Biofilm and solid-state\\u000a fermentations were carried out on perlite as inert support, and lactose was used as a carbon source in the three culture systems.\\u000a In cryo-scanning electron microscopy, biofilm and solid-state cultures gave similar morphological patterns and confirmed that\\u000a both spore first

Norma N. Gamarra; Gretty K. Villena; Marcel Gutiérrez-Correa

2010-01-01

145

Cloning, characterization, and expression of two ?-amylase genes from Aspergillus niger var. awamori  

Microsoft Academic Search

Using synthetic oligonucleotide probes, we cloned genomic DNA sequences encoding an a-amylase gene from Aspergillus niger var. awamori (A. awamori) on a 5.8 kb EcoRI fragment. Hybridization experiments, using a portion of this cloned fragment to probe DNA from A. awamori, suggested the presence of two a-amylase gene copies which were subsequently cloned as 7 kb (designated as amyA) and

David R. Korman; Frank T. Bayliss; Christopher C. Barnett; Cynthia L. Carmona; Katherine H. Kodama; Theresa J. Royer; Sheryl A. Thompson; Michael Ward; Lori J. Wilson; Randy M. Berka

1990-01-01

146

Optimization of Inulinase Fermentation Conditions of Aspergillus Niger X-6 Using Respose Surface Methodology  

Microsoft Academic Search

Inulinase is a hydrolase used for inulin hydrolysis to produce functional fructooligosaccharides and fructose. The objective of the research was to obtain the optimum fermentation conditions of inulinase from Aspergillus niger X-6 mutated by microwave treatment with the Plackett-Burmen design and response surface methodology. The content of wheat bran, inulin, peptone, yeast extract, fermentation time, temperature, pH, and inoculum affecting

Denglin Luo; Haili Yuan; Xiaoyu Zeng; Jianxue Liu

2010-01-01

147

Continuous production of citric acid from dairy wastewater using immobilized Aspergillus niger ATCC 9142  

Microsoft Academic Search

The continuous production of citric acid from dairy wastewater was investigated using calcium-alginate immobilizedAspergillus niger ATCC 9142. The citric acid productivity and yield were strongly affected by the culture conditions. The optimal pH, temperature,\\u000a and dilution rate were 3.0, 30°C, and 0.025 h?1, respectively. Under optimal culture conditions, the maximum productivity, concentration, and yield of citric acid produced\\u000a by the

Se-Kwon Kim; Pyo-Jam Park; Hee-Guk Byun

2002-01-01

148

Amylase production by Aspergillus niger in submerged cultivation on two wastes from food industries  

Microsoft Academic Search

Synthesis of amylase and protease by Aspergillus niger strain UO-1 was followed in media prepared with brewery (BW) and meat (MPW) wastewaters supplemented with different starch concentrations. The highest amylase (70.29 and 60.12EU\\/mL) and protease (6.11 and 6.03EU\\/mL) production were, respectively, obtained in the BW and MPW media supplemented with 40g of starch\\/L of medium after 88h of fermentation. In

Mabel Salas Hernández; Marilú Rodríguez Rodríguez; Nelson Pérez Guerra; Renato Pérez Rosés

2006-01-01

149

Spore cell wall components of Aspergillus niger elicit downy mildew disease resistance in pearl millet  

Microsoft Academic Search

Elicitors derived from the cell wall of fungi are shown to be active in eliciting resistance in plants against a wide range\\u000a of pathogens. In the present study carbohydrate components from the autoclaved spore cell wall ofAspergillus niger were prepared as aqueous suspensions and tested for defense response in pearl millet (Pennisetum glaucum (L.) R.Br.) against the oomycetous downy mildew

C. K. Hindumathy; S. Shailasree; K. Ramachandra Kini; H. Shekar Shetty

2006-01-01

150

Nonhealing scalp wound infected with Aspergillus niger in an elderly patient.  

PubMed

Cutaneous aspergillosis is a rare infection most often seen in immunocompromised patients. We report a case of primary cutaneous aspergillosis infection in a nonhealing scalp wound of an immunocompetent elderly patient. The patient had a cutaneous malignancy of the scalp treated with surgical excision but complicated by poor wound healing. Fungal culture of the nonhealing wound revealed Aspergillus niger. The nonhealing wound subsequently resolved with retapamulin ointment 1% and ketoconazole gel 2%. PMID:21644495

Robinson, Amanda; Fien, Sari; Grassi, Marcelle A

2011-04-01

151

[Aspergillus niger responsible for a tracheo-oesophageal fistula in an immunocompetent patient].  

PubMed

Tracheal or bronchial aspergillar locations are rare. They are mainly found in patients with general or localised immune deficiency. The authors report the case of a 53-year-old Vietnamese immunocompetent patient without any factors of risk who suddenly came down with a perforation syndrome indicating a tracheo-oesophageal fistula. The bronchial samples helped identify Aspergillus niger as the agent incriminated. Surgical treatment associated with an antifungal treatment provided a cure without any recurrence for 3 years. PMID:19878804

Tran, N T; Nguyen, T P; Homasson, J P

2009-06-11

152

Mechanism of hexavalent chromium removal by dead fungal biomass of Aspergillus niger  

Microsoft Academic Search

When synthetic wastewater containing Cr(VI) was placed in contact with the dead fungal biomass of Aspergillus niger, the Cr(VI) was completely removed from aqueous solution, whereas Cr(III), which was not initially present, appeared in aqueous solution. Desorption and X-ray photoelectron spectroscopy (XPS) studies showed that most of the Cr bound on the biomass was in trivalent form. These results indicated

Donghee Park; Yeoung-Sang Yun; Ji Hye Jo; Jong Moon Park

2005-01-01

153

Attempts at improving citric acid fermentation by Aspergillus niger in beet-molasses medium.  

PubMed

Natural oils with high unsaturated fatty acids content when added at concentrations of 2% and 4% (v/v) to beet molasses (BM) medium caused a considerable increase in citric acid yield from Aspergillus niger. The fermentation capacities were also examined for production of citric acid using BM-oil media under different fermentation conditions. Maximum citric acid yield was achieved in surface culture in the presence of 4% olive oil after 12 days incubation. PMID:12137276

Adham, Nehad Z

2002-08-01

154

Effect of water activity on ochratoxin A production by Aspergillus niger aggregate species  

Microsoft Academic Search

The effect of water activity (aw) (0.82–0.99) on growth and ochratoxin A (OTA) production by twelve Aspergillus niger aggregate strains, cultured in Czapek Yeast Autolysate agar (CYA) and Yeast Extract Sucrose agar (YES), was studied for an incubation period of 30 days. The strains were selected to include diverse sources, different reported abilities to produce OTA and different ITS-5.8 S

A. Esteban; M. L. Abarca; M. R. Bragulat; F. J. Cabañes

2006-01-01

155

Effect of pH on ochratoxin A production by Aspergillus niger aggregate species  

Microsoft Academic Search

The effect of pH (2–10) on growth and ochratoxin A (OTA) production by 12 Aspergillus niger aggregate strains was studied in two culture media: Czapek yeast autolysate agar (CYA) and yeast extract sucrose agar (YES), over 30 days. The strains were selected to include different sources, different reported abilities to produce OTA and different ITS-5.8S rDNA RFLP patterns. YES was

A. Esteban; M. L. Abarca; M. R. Bragulat; F. J. Cabañes

2006-01-01

156

Crystal Structure of Aspergillus niger Isopullulanase, a Member of Glycoside Hydrolase Family 49  

Microsoft Academic Search

An isopullulanase (IPU) from Aspergillus niger ATCC9642 hydrolyzes ?-1,4-glucosidic linkages of pullulan to produce isopanose. Although IPU does not hydrolyze dextran, it is classified into glycoside hydrolase family 49 (GH49), major members of which are dextran-hydrolyzing enzymes. IPU is highly glycosylated, making it difficult to obtain its crystal. We used endoglycosidase Hf to cleave the N-linked oligosaccharides of IPU, and

Masahiro Mizuno; Atsushi Koide; Akihiro Yamamura; Hiromi Akeboshi; Hiromi Yoshida; Shigehiro Kamitori; Yoshiyuki Sakano; Atsushi Nishikawa; Takashi Tonozuka

2008-01-01

157

Enzymatic detergent formulation containing amylase from Aspergillus niger: A comparative study with commercial detergent formulations  

Microsoft Academic Search

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 (3.9Uml?1±0.2) in submerged culture and its amylase demonstrated excellent activity

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

2006-01-01

158

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

Microsoft Academic Search

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

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

2006-01-01

159

Presence and regulation of ATP:citrate lyase from the citric acid producing fungus Aspergillus niger  

Microsoft Academic Search

ATP:citrate lyase (EC 4.1.3.8) has been identified in cell-free extracts from the filamentous fungus Aspergillus niger. The enzyme was located in the cytosol. It exhibits an activity at least ten times that of acetate-CoA-kinase (EC 6.2.1.1) during growth on carbohydrates as carbon sources, and is thus considered responsible for acetyl-CoA formation under these conditions. It is formed constitutively and its

A. Pfitzner; C. P. Kubicek; M. Röhr

1987-01-01

160

Production and characterization of a highly active cellobiase from Aspergillus niger grown in solid state fermentation  

Microsoft Academic Search

Summary  \\u000a Aspergillus niger produced extracellular cellobiase when grown on different lignocellulosic substrates in solid state fermentation. The enzyme activity and yield were variable according to the carbon source. In Vogel’s medium, the cellobiase productivity was significantly higher on wheat bran, followed by Leptochloa fusca (kallar grass) straw augmented with corn steep liquor. Maximum yield of cellobiase\\/g wheat bran was significantly

Muhammad Ibrahim Rajoka; Muhammad Waheed Akhtar; Atif Hanif; A. M. Khalid

2006-01-01

161

Production of high activity thermostable phytase from thermotolerant Aspergillus niger in solid state fermentation  

Microsoft Academic Search

  The thermotolerant fungus, Aspergillus niger NCIM 563, was used for production of extracellular phytase on agricultural residues: wheat bran, mustard cake, cowpea meal,\\u000a groundnut cake, coconut cake, cotton cake and black bean flour in solid state fermentation (SSF). Maximum enzyme activity\\u000a (108?U?g?1 dry mouldy bran, DMB) was obtained with cowpea meal. During the fermentation phytic acid was hydrolysed completely with

T N Mandviwala; J M Khire

2000-01-01

162

Air pressure pulsation solid state fermentation of feruloyl esterase by Aspergillus niger  

Microsoft Academic Search

Air pressure pulsation solid state fermentation (APP-SSF) was applied to produce feruloyl esterase (FAE) by Aspergillus niger. With the optimization of some variables by orthogonal design, the optimal condition obtained was 0.2MPa (gauge pressure) of high pressure intensity, 30min of low pressure duration and 20s of high pressure duration. Based on the optimized condition, the APP-SSF achieved the reasonable enzyme

W. Zeng; H. Z. Chen

2009-01-01

163

Suitability of Vader for Transposon-Mediated Mutagenesis in Aspergillus niger ? †  

PubMed Central

The filamentous fungus Aspergillus niger is widely used in biotechnological applications. Strain CBS513.88 is known to harbor 21 copies of the nonautonomous transposon Vader. Upon selection of chlorate-resistant A. niger colonies, one Vader copy was found integrated in the nirA gene. This copy was used for vector construction and development of a transposon-tagging method. Vader showed an excision frequency of about 1 in 2.2 × 105 conidiospores. A total of 95 of 97 colonies analyzed exhibited an excision event at the DNA level, and Vader footprints were found. By employing thermal asymmetric interlaced (TAIL)-PCR, the reintegration sites of 21 independent excision events were determined. All reintegration events occurred within or very close to genes. Therefore, this method can be used for transposon mutagenesis in A. niger.

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

2011-01-01

164

Genome sequencing and analysis of the versatile cell factory Aspergillus niger CBS 513.88.  

PubMed

The filamentous fungus Aspergillus niger is widely exploited by the fermentation industry for the production of enzymes and organic acids, particularly citric acid. We sequenced the 33.9-megabase genome of A. niger CBS 513.88, the ancestor of currently used enzyme production strains. A high level of synteny was observed with other aspergilli sequenced. Strong function predictions were made for 6,506 of the 14,165 open reading frames identified. A detailed description of the components of the protein secretion pathway was made and striking differences in the hydrolytic enzyme spectra of aspergilli were observed. A reconstructed metabolic network comprising 1,069 unique reactions illustrates the versatile metabolism of A. niger. Noteworthy is the large number of major facilitator superfamily transporters and fungal zinc binuclear cluster transcription factors, and the presence of putative gene clusters for fumonisin and ochratoxin A synthesis. PMID:17259976

Pel, Herman J; de Winde, Johannes H; Archer, David B; Dyer, Paul S; Hofmann, Gerald; Schaap, Peter J; Turner, Geoffrey; de Vries, Ronald P; Albang, Richard; Albermann, Kaj; Andersen, Mikael R; Bendtsen, Jannick D; Benen, Jacques A E; van den Berg, Marco; Breestraat, Stefaan; Caddick, Mark X; Contreras, Roland; Cornell, Michael; Coutinho, Pedro M; Danchin, Etienne G J; Debets, Alfons J M; Dekker, Peter; van Dijck, Piet W M; van Dijk, Alard; Dijkhuizen, Lubbert; Driessen, Arnold J M; d'Enfert, Christophe; Geysens, Steven; Goosen, Coenie; Groot, Gert S P; de Groot, Piet W J; Guillemette, Thomas; Henrissat, Bernard; Herweijer, Marga; van den Hombergh, Johannes P T W; van den Hondel, Cees A M J J; van der Heijden, Rene T J M; van der Kaaij, Rachel M; Klis, Frans M; Kools, Harrie J; Kubicek, Christian P; van Kuyk, Patricia A; Lauber, Jürgen; Lu, Xin; van der Maarel, Marc J E C; Meulenberg, Rogier; Menke, Hildegard; Mortimer, Martin A; Nielsen, Jens; Oliver, Stephen G; Olsthoorn, Maurien; Pal, Karoly; van Peij, Noël N M E; Ram, Arthur F J; Rinas, Ursula; Roubos, Johannes A; Sagt, Cees M J; Schmoll, Monika; Sun, Jibin; Ussery, David; Varga, Janos; Vervecken, Wouter; van de Vondervoort, Peter J J; Wedler, Holger; Wösten, Han A B; Zeng, An-Ping; van Ooyen, Albert J J; Visser, Jaap; Stam, Hein

2007-01-28

165

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

PubMed Central

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.

Abouzied, M M; Reddy, C A

1986-01-01

166

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

PubMed

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

Srivastava, Anita; Kar, Rita

2009-12-01

167

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

PubMed Central

Extracellular tannase and gallic acid were produced optimally under submerged fermentation at 37 0C, 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 0C and 6.2 respectively which shifted to 40 0C and 5.8 on immobilization in alginate beads. Activity of the enzyme was inhibited by Zn+2, Ca+, Mn+2, Mg+2, Ba+2and 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.

Srivastava, Anita; Kar, Rita

2009-01-01

168

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

PubMed

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 40°C while the corresponding values of the soluble enzyme were 5.8 and 35°C. Maximum tannin removal of 73.6% was obtained at 40°C 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 37°C and 150 rpm in the same time period. The immobilized beads could be used repeatedly till 7th cycle with 77% efficiency. When preserved at 6°C 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

Srivastava, Anita; Kar, Rita

2010-03-16

169

Biocatalytic potential of laccase-like multicopper oxidases from Aspergillus niger  

PubMed Central

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.

2012-01-01

170

Improvement on citric acid production in solid-state fermentation by Aspergillus niger LPB BC mutant using citric pulp.  

PubMed

Citric acid (CA) production has been conducted through a careful strain selection, physical-chemical optimization and mutation. The aim of this work was to optimize the physical-chemical conditions of CA production by solid-state fermentation (SSF) using the Aspergillus niger LPB BC strain, which was isolated in our laboratory. The parental and mutant strain showed a good production of CA using citric pulp (CP) as a substrate. The physical-chemical parameters were optimized and the best production was reached at 65% moisture, 30 degrees C and pH 5.5. The influence of the addition of commercial and alternative sugars, nitrogen sources, salts, and alcohols was also studied. The best results (445.4 g of CA/kg of CP) were obtained with sugarcane molasses and 4% methanol (v/w). The mutagenesis induction of LPB BC was performed with UV irradiation. Eleven mutant strains were tested in SSF where two mutants showed a higher CA production when compared to the parental strain. A. niger LPB B3 produced 537.6 g of CA/kg of CP on the sixth day of fermentation, while A. niger LPB B6 produced 616.5 g of CA/kg of CP on the fourth day of fermentation, representing a 19.5% and 37% gain, respectively. PMID:18925364

Rodrigues, Cristine; Vandenberghe, Luciana Porto de Souza; Teodoro, Juliana; Pandey, Ashok; Soccol, Carlos Ricardo

2008-10-17

171

Cloning and molecular characterization of a soluble epoxide hydrolase from Aspergillus niger that is related to mammalian microsomal epoxide hydrolase.  

PubMed Central

Aspergillus niger strain LCP521 harbours a highly processive epoxide hydrolase (EH) that is of particular interest for the enantioselective bio-organic synthesis of fine chemicals. In the present work, we report the isolation of the gene and cDNA for this EH by use of inverse PCR. The gene is composed of nine exons, the first of which is apparently non-coding. The deduced protein of the A. niger EH shares significant sequence similarity with the mammalian microsomal EHs (mEH). In contrast to these, however, the protein from A. niger lacks the common N-terminal membrane anchor, in line with the fact that this enzyme is, indeed, soluble in its native environment. Recombinant expression of the isolated cDNA in Escherichia coli yielded a fully active EH with similar characteristics to the fungal enzyme. Sequence comparison with mammalian EHs suggested that Asp(192), Asp(348) and His(374) constituted the catalytic triad of the fungal EH. This was subsequently substantiated by the analysis of respective mutants constructed by site-directed mutagenesis. The presence of an aspartic acid residue in the charge-relay system of the A. niger enzyme, in contrast to a glutamic acid residue in the respective position of all mEHs analysed to date, may be one important contributor to the exceptionally high turnover number of the fungal enzyme when compared with its mammalian relatives. Recombinant expression of the enzyme in E. coli offers a versatile tool for the bio-organic chemist for the chiral synthesis of a variety of fine chemicals.

Arand, M; Hemmer, H; Durk, H; Baratti, J; Archelas, A; Furstoss, R; Oesch, F

1999-01-01

172

Cloning and molecular characterization of a soluble epoxide hydrolase from Aspergillus niger that is related to mammalian microsomal epoxide hydrolase.  

PubMed

Aspergillus niger strain LCP521 harbours a highly processive epoxide hydrolase (EH) that is of particular interest for the enantioselective bio-organic synthesis of fine chemicals. In the present work, we report the isolation of the gene and cDNA for this EH by use of inverse PCR. The gene is composed of nine exons, the first of which is apparently non-coding. The deduced protein of the A. niger EH shares significant sequence similarity with the mammalian microsomal EHs (mEH). In contrast to these, however, the protein from A. niger lacks the common N-terminal membrane anchor, in line with the fact that this enzyme is, indeed, soluble in its native environment. Recombinant expression of the isolated cDNA in Escherichia coli yielded a fully active EH with similar characteristics to the fungal enzyme. Sequence comparison with mammalian EHs suggested that Asp(192), Asp(348) and His(374) constituted the catalytic triad of the fungal EH. This was subsequently substantiated by the analysis of respective mutants constructed by site-directed mutagenesis. The presence of an aspartic acid residue in the charge-relay system of the A. niger enzyme, in contrast to a glutamic acid residue in the respective position of all mEHs analysed to date, may be one important contributor to the exceptionally high turnover number of the fungal enzyme when compared with its mammalian relatives. Recombinant expression of the enzyme in E. coli offers a versatile tool for the bio-organic chemist for the chiral synthesis of a variety of fine chemicals. PMID:10548561

Arand, M; Hemmer, H; Dürk, H; Baratti, J; Archelas, A; Furstoss, R; Oesch, F

1999-11-15

173

Enantioselective hydrolysis of epichlorohydrin using whole Aspergillus niger ZJB-09173 cells in organic solvents.  

PubMed

The enantioselective hydrolysis of racemic epichlorohydrin for the production of enantiopure (S)-epichlorohydrin using whole cells of Aspergillus niger ZJB-09173 in organic solvents was investigated. Cyclohexane was used as the reaction medium based on the excellent enantioselectivity of epoxide hydrolase from A. niger ZJB- 09173 in cyclohexane. However, cyclohexane had a negative effect on the stability of epoxide hydrolase from A. niger ZJB-09173. In the cyclohexane medium, substrate inhibition, rather than product inhibition of catalysis, was observed in the hydrolysis of racemic epichlorohydrin using A. niger ZJB-09173. The racemic epichlorohydrin concentration was markedly increased by continuous feeding of substrate without significant decline of the yield. Ultimately, 18.5% of (S)-epichlorohydrin with 98 percent enantiomeric excess from 153.6 mM of racemic epichlorohydrin was obtained by the dry cells of A. niger ZJB-09173, which was the highest substrate concentration in the production of enantiopure (S)-epichlorohydrin by epoxide hydrolases using an organic solvent medium among the known reports. PMID:22922194

Jin, Huo-Xi; Hu, Zhong-Ce; Zheng, Yu-Guo

2012-09-01

174

Spatial and Developmental Differentiation of Mannitol Dehydrogenase and Mannitol-1-Phosphate Dehydrogenase in Aspergillus niger?†  

PubMed Central

The presence of a mannitol cycle in fungi has been subject to discussion for many years. Recent studies have found no evidence for the presence of this cycle and its putative role in regenerating NADPH. However, all enzymes of the cycle could be measured in cultures of Aspergillus niger. In this study we have analyzed the localization of two enzymes from the pathway, mannitol dehydrogenase and mannitol-1-phosphate dehydrogenase, and the expression of their encoding genes in nonsporulating and sporulating cultures of A. niger. Northern analysis demonstrated that mpdA was expressed in both sporulating and nonsporulating mycelia, while expression of mtdA was expressed only in sporulating mycelium. More detailed studies using green fluorescent protein and dTomato fused to the promoters of mtdA and mpdA, respectively, demonstrated that expression of mpdA occurs in vegetative hyphae while mtdA expression occurs in conidiospores. Activity assays for MtdA and MpdA confirmed the expression data, indicating that streaming of these proteins is not likely to occur. These results confirm the absence of the putative mannitol cycle in A. niger as two of the enzymes of the cycle are not present in the same part of A. niger colonies. The results also demonstrate the existence of spore-specific genes and enzymes in A. niger.

Aguilar-Osorio, Guillermo; vanKuyk, Patricia A.; Seiboth, Bernhard; Blom, Dirk; Solomon, Peter S.; Vinck, Arman; Kindt, Frits; Wosten, Han A. B.; de Vries, Ronald P.

2010-01-01

175

Potential of Fourier transform infrared spectroscopy (FT-IR) to differentiate environmental Aspergillus fungi species A. niger, A. ochraceus, and A. westerdijkiae using two different methodologies.  

PubMed

We assessed the ability of Fourier transform infrared spectroscopy (FT-IR) to differentiate three important and morphologically similar Aspergillus species: A. ochraceus and A. westerdijkiae, and A. niger. Fungi were processed by two methods, powdered mycelia and conidiospore-saline solution, and then recorded in a spectrometer. Second derivatives with nine points of smoothing were applied as spectra data pretreatment. Partial least squares regression was used for the species comparison models and a prediction test was used to evaluate the models. The powdered-mycelia methodology correctly identified 100% of the prediction test set to discriminate A. niger from A. ochraceus and A. westerdijkiae; in addition, it had a 86.6% success rate in discriminating A. ochraceus and A. westerdijkiae. This is the first time a study assessed the ability of FT-IR to differentiate A. niger, A. ochraceus, and A. westerdijkiae, and we believe this technique is very promising for classifying and distinguish fungi isolates. PMID:23452490

Tralamazza, Sabina Moser; Bozza, Angela; Destro, João Guilherme Rodenbusch; Rodríguez, Jaime Iván; do Rocio Dalzoto, Patricia; Pimentel, Ida Chapaval

2013-03-01

176

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

PubMed Central

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 4°C 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.

2011-01-01

177

Gene cloning and enzymatic characterization of an endoprotease Endo-Pro-Aspergillus niger.  

PubMed

A novel endoprotease Endo-Pro-Aspergillus niger (endoprotease EPR) was first successfully expressed at high level in the methylotrophic yeast Pichia pastoris and the purification procedure was established. The endoprotease EPR is 95 % identity with proline specific endopeptidase from A. niger CBS513.88 (EMBL; AX458699), while sharing low identity with those from other microorganisms. The purified endoprotease EPR was a monomer of 60 kDa. Furthermore, the peptide mass fingerprinting (PMF) analysis confirmed that the purified protein was an endoprotease Endo-Pro-Aspergillus niger. A three-dimensional model revealed that the active site of the enzyme was located in Ser(179)-Asp(458)-His(491), based on template 3n2zB with sequence identity of 17.6 %. The optimum pH and temperature of the endoprotease EPR were pH 4-5 and 35 °C, and the stabilities were pH 3-7 and 15-60 °C, respectively. Furthermore, the endoprotease EPR had the ability to digest peptides with the C-terminal of proline as well as alanine, and was also capable of hydrolyzing larger peptides. The properties of the endoprotease EPR made it a highly promising candidate for future application in the field of brewing and food process. PMID:23685896

Kang, Chao; Yu, Xiao-Wei; Xu, Yan

2013-05-18

178

Generation, annotation, and analysis of an extensive Aspergillus niger EST collection  

PubMed Central

Background Aspergillus niger, a saprophyte commonly found on decaying vegetation, is widely used and studied for industrial purposes. Despite its place as one of the most important organisms for commercial applications, the lack of available information about its genetic makeup limits research with this filamentous fungus. Results We present here the analysis of 12,820 expressed sequence tags (ESTs) generated from A. niger cultured under seven different growth conditions. These ESTs identify about 5,108 genes of which 44.5% code for proteins sharing similarity (E ? 1e -5) with GenBank entries of known function, 38% code for proteins that only share similarity with GenBank entries of unknown function and 17.5% encode proteins that do not have a GenBank homolog. Using the Gene Ontology hierarchy, we present a first classification of the A. niger proteins encoded by these genes and compare its protein repertoire with other well-studied fungal species. We have established a searchable web-based database that includes the EST and derived contig sequences and their annotation. Details about this project and access to the annotated A. niger database are available. Conclusion This EST collection and its annotation provide a significant resource for fundamental and applied research with A. niger. The gene set identified in this manuscript will be highly useful in the annotation of the genome sequence of A. niger, the genes described in the manuscript, especially those encoding hydrolytic enzymes will provide a valuable source for researchers interested in enzyme properties and applications.

Semova, Natalia; Storms, Reginald; John, Tricia; Gaudet, Pascale; Ulycznyj, Peter; Min, Xiang Jia; Sun, Jian; Butler, Greg; Tsang, Adrian

2006-01-01

179

Isolation of aminopeptidase from Aspergillus flavus.  

PubMed

A mixture of aminopeptidase and neutral protease from the Aspergillus flavus mold obtained by chromatography on DEAE-Sephadex was fractionated by chromatography on the hydroxyalkyl methacrylate gel with chemically bonded 1,6 hexamethylene diamine and D-leucine. Aminopeptidase thus obtained was electrophoretically homogeneous. Conditions for chromatography were worked out allowing a one stage isolation of a highly active aminopeptidase sample directly from the alcoholic precipitate of the culture medium of the Aspergillus flavus mold. PMID:814927

Turková, J; Valentová, O; Coupek, J

1976-02-20

180

Preliminary X-ray diffraction analysis of thermostable ?-1,4-mannanase from Aspergillus niger BK01.  

PubMed

?-1,4-Mannanase (?-mannanase) is a key enzyme in decomposing mannans, which are abundant components of hemicelluloses in the plant cell wall. Therefore, mannan hydrolysis is highly valuable in a wide array of industrial applications. ?-Mannanase isolated from Aspergillus niger BK01 (ManBK) was classified into glycoside hydrolase family GH5. ManBK holds great potential in biotechnological applications owing to its high thermostability. Here, ManBK was expressed and purified in Pichia pastoris and the recombinant protein was crystallized. Crystals belonging to the orthorhombic space group C2221, with unit-cell parameters a = 93.58, b = 97.05, c = 147.84?Å, were obtained by the sitting-drop vapour-diffusion method and diffracted to 1.57?Å resolution. Structure determination using molecular-replacement methods is in progress. PMID:24100557

Luo, Wenhua; Huang, Jian Wen; Huang, Chun Hsiang; Huang, Ting Yung; Chan, Hsiu Chien; Liu, Je Ruei; Guo, Rey Ting; Chen, Chun Chi

2013-09-28

181

Microbial metabolism of methyl protodioscin by Aspergillus niger culture--a new androstenedione producing way from steroid.  

PubMed

Methyl protodioscin (1), a natural furostanol biglycoside steroid, was a preclinical anticancer drug, which showed potent activity against most cell lines from leukemia and solid tumors in the National Cancer Institute's (NCI) human cancer panel. Metabolism of methyl protodioscin by Aspergillus niger was investigated. Seven metabolites were isolated and identified. Two main metabolites were pregnane glycosides and four were furostanol glycosides, together with the aglycone. It was found that steroidal saponin skeleton could be converted to pregnenolone skeleton only using microbial methods, which must have chemical procedures in the reported literatures. The proposed biosynthetic pathways of the microbial conversion products of methyl protodioscin were drawn. The found enriched the reaction types of microbial bioconversion and provided a new producing way of androstenedione from steroid. Most metabolites showed strong cytotoxic activities against HepG2, NCI-H460, HeLa, and MCF-7 cell lines. PMID:16713252

He, Xiangjiu; Liu, Bo; Wang, Guanghui; Wang, Xinluan; Su, Lina; Qu, Gexia; Yao, Xinsheng

2006-05-18

182

Early detection of Aspergillus carbonarius and A. niger on table grapes: a tool for quality improvement.  

PubMed

Aspergillus carbonarius and A. niger aggregate are the main fungal contaminants of table grapes. Besides their ability to cause black rot, they can produce ochratoxin A (OTA), a mycotoxin that has attracted increasing attention worldwide. The objective of this work was to set up a simple and rapid molecular method for the early detection of both fungi in table grapes before fungal development becomes evident. Polymerase chain reaction (PCR)-based assays were developed by designing species-specific primers based on the polyketide synthases (PKS(S)) sequences of A. carbonarius and A. niger that have recently been demonstrated to be involved in OTA biosynthesis. Three table grape varieties (Red globe, Crimson seedless, and Italia) were inoculated with A. carbonarius and A. niger aggregate strains producing OTA. The extracted DNA from control (non-inoculated) and inoculated grapes was amplified by PCR using ACPKS2F-ACPKS2R for A. carbonarius and ANPKS5-ANPKS6 for A. niger aggregate. Both primers allowed a clear detection, even in symptomless samples. PCR-based methods are considered to be a good alternative to traditional diagnostic means for the early detection of fungi in complex matrix for their high specificity and sensitivity. The results obtained could be useful for the definition of a 'quality label' for tested grapes to improve the safety measures taken to guarantee the production of fresh table grapes. PMID:20582777

Ayoub, F; Reverberi, M; Ricelli, A; D'Onghia, A M; Yaseen, T

2010-09-01

183

The faeA genes from Aspergillus niger and Aspergillus tubingensis encode ferulic acid esterases involved in degradation of complex cell wall polysaccharides.  

PubMed Central

We report the cloning and characterization of a gene encoding a ferulic acid esterase, faeA, from Aspergillus niger and Aspergillus tubingensis. The A. niger and A. tubingensis genes have a high degree of sequence identity and contain one conserved intron. The gene product, FAEA, was overexpressed in wild-type A. tubingensis and a protease-deficient A. niger mutant. Overexpression of both genes in wild-type A. tubingensis and an A. niger protease-deficient mutant showed that the A. tubingensis gene product is more sensitive to degradation than the equivalent gene product from A. niger. FAEA from A. niger was identical to A. niger FAE-III (C. B. Faulds and G. Williamson, Microbiology 140:779-787, 1994), as assessed by molecular mass, pH and temperature optima, pI, N-terminal sequence, and activity on methyl ferulate. The faeA gene was induced by growth on wheat arabinoxylan and sugar beet pectin, and its gene product (FAEA) released ferulic acid from wheat arabinoxylan. The rate of release was enhanced by the presence of a xylanase. FAEA also hydrolyzed smaller amounts of ferulic acid from sugar beet pectin, but the rate was hardly affected by addition of an endo-pectin lyase.

de Vries, R P; Michelsen, B; Poulsen, C H; Kroon, P A; van den Heuvel, R H; Faulds, C B; Williamson, G; van den Hombergh, J P; Visser, J

1997-01-01

184

A novel method to extract chromium impurity using facultative marine Aspergillus niger and magnetic fluid  

NASA Astrophysics Data System (ADS)

Chromium (VI) tolerance and removal efficiency of facultative marine fungus Aspergillus niger/ in the absence and presence of MnZn ferrite magnetic fluid (MF) has been studied. The fungus exhibits a luxuriant growth in the presence of hexavalent chromium at the concentration 25 mg/L. The MF also exhibits a positive effect on biomass accumulation. Percentage removal of chromium ranged 32-87%, while that in the presence of MF ranged 42-83%. Temporal effect studies on chromium removal revealed more than 50% Cr removal in the presence of MF on the fifth day. These preliminary observations indicate a possibility of harnessing young cultures of A. niger with nanoparticles dispersed in the magnetic fluid for chromium removal. Figs 2, Refs 17.

Davariya, V.; Vala, A. K.; Desai, R.; Upadhyay, R. V.

2007-12-01

185

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

SciTech Connect

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.

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

1985-01-01

186

Development of a serial bioreactor system for direct ethanol production from starch using Aspergillus niger and Saccharomyces cerevisiae  

Microsoft Academic Search

Aspergillus niger hyphae were found to grow with unliquefied potato starch under aerobic conditions, but did not grow under anaerobic conditions.\\u000a The raw culture ofA. niger catalyzed saccharification of potato starch to glucose, producing approximately 12 g glucose\\/L\\/day\\/ The extracellular enzyme\\u000a activity was decreased in proportion to incubation time, and approximately 64% of initial activity was maintained after 3\\u000a days.

Bo Young Jeon; Soo Jin Kim; Dae Hee Kim; Byung Kwan Na; Doo Hyun Park; Hung Thuan Tran; Ruihong Zhang; Dae Hee Ahn

2007-01-01

187

Effect of growth temperature on lipid fatty acids of four fungi ( Aspergillus niger, Neurospora crassa, Penicillium chrysogenum , and Trichoderma reesei )  

Microsoft Academic Search

The effect of growth temperature on the lipid fatty acid composition was studied over a temperature range from 35 to 10° C\\u000a with 5° C intervals in four exponentially growing fungi:Aspergillus niger, Neurospora crassa, Penicillium chrysogenum, andTrichoderma reesei. Fatty acid unsaturation increased inA. niger, P. chrysogenum, andT. reesei when the temperature was lowered to 20–15, 20, and 26–20° C, respectively.

Merja Suutari

1995-01-01

188

Citric acid production from sugar cane molasses by 2-deoxyglucose-resistant mutant strain of Aspergillus niger  

Microsoft Academic Search

Citric acid production from sugar cane molasses byAspergillus niger NIAB 280 was studied in a batch cultivation process. A maximum of 90 g\\/L total sugar was utilized in citric acid production\\u000a medium. From the parental strainA. niger, mutant strains showing resistance to 2-deoxyglucose in Vogal's medium containing molasses as a carbon source were induced\\u000a by ?-irradiation. Among the new series

S. Parvez; M. I. Rajoka; M. N. Ahmed; F. Latif; R. Shahid; K. A. Malik

1998-01-01

189

The transcription factor HACA mediates the unfolded protein response in Aspergillus niger , and up-regulates its own transcription  

Microsoft Academic Search

The unfolded protein response (UPR) involves a complex signalling pathway in which the transcription factor HACA plays a central role. Here we report the cloning and characterisation of the hacA gene and its product from Aspergillus niger. ER (endoplasmic reticulum) stress results in the splicing of an unconventional 20-nt intron from the A. niger hacA mRNA, and is associated with

H. J. Mulder; M. Saloheimo; M. Penttilä; S. M. Madrid

2004-01-01

190

pgaA and pgaB encode two constitutively expressed endopolygalacturonases of Aspergillus niger.  

PubMed Central

The nucleotide sequence data for pgaA and pgaB have been deposited with the EMBL, GenBank and DDBJ Databases under accession numbers Y18804 and Y18805 respectively. pgaA and pgaB, two genes encoding endopolygalacturonases (PGs, EC 3.2.1.15) A and B, were isolated from a phage genomic library of Aspergillus niger N400. The 1167 bp protein coding region of the pgaA gene is interrupted by one intron, whereas the 1234 bp coding region of the pgaB gene contains two introns. The corresponding proteins, PGA and PGB, consist of 370 and 362 amino acid residues respectively. Northern-blot analysis revealed that pgaA- and pgaB-specific mRNA accumulate in mycelia grown on sucrose. mRNAs are also present upon transfer to media containing D-galacturonic acid and pectin. Recombinant PGA and PGB were characterized with respect to pH optimum, activity on polygalacturonic acid, and mode of action and kinetics on oligogalacturonates of different chain length (n=3-7). At their pH optimum the specific activities in a standard assay for PGA (pH 4.2) and PGB (pH 5.0) were 16.5 mu+kat.mg(-1) and 8.3 mu+kat.mg(-1) respectively. Product progression analysis, using polygalacturonate as a substrate, revealed a random cleavage pattern for both enzymes and indicated processive behaviour for PGA. This result was confirmed by analysis of the mode of action using oligogalacturonates. Processivity was observed when the degree of polymerization of the substrate exceeded 6. Using pectins of various degrees of methyl esterification, it was shown that PGA and PGB both preferred partially methylated substrates.

Parenicova, L; Benen, J A; Kester, H C; Visser, J

2000-01-01

191

Effects of metal ions on simultaneous production of glucose oxidase and catalase by Aspergillus niger.  

PubMed

The effects of various metal ions on the simultaneous production of glucose oxidase and catalase by Aspergillus niger were investigated. Calcium carbonate induced synthesis of both enzymes. The induction of calcium carbonate was accompanied by a metabolic shift from the glycolytic pathway (EMP, Embden-Meyerhof-Parnas) to direct oxidation of glucose by glucose oxidase. The time course of the biosynthesis of both enzymes is reported. The logistic model was in good agreement with the experimental growth results. The production of both enzymes was growth-associated. Finally, a model of growth and product formation was also proposed. PMID:11169035

Liu, J Z; Huang, Y Y; Liu, J; Weng, L P; Ji, L N

2001-01-01

192

Anti-fungal activity of SiO2/Ag2S nanocomposites against Aspergillus niger.  

PubMed

Submicron particles of amorphous SiO(2) have been used to grow Ag(2)S nanophases at their surfaces. SEM and TEM analysis showed morphological well-defined nanocomposite particles consisting of Ag(2)S nanocrystals dispersed over the silica surfaces. These SiO(2)/Ag(2)S nanocomposites were investigated as anti-fungal agents against Aspergillus niger in different experimental conditions, including as nanofillers in cellulosic fibres. The anti-fungal activity in these composite systems is suggested to result from a synergistic effect due to Ag(2)S anti-fungal centres and the SiO(2) surfaces in promoting the adsorption of the fungus. PMID:19709863

Fateixa, Sara; Neves, Márcia C; Almeida, Adelaide; Oliveira, João; Trindade, Tito

2009-08-05

193

Fractionation of Aspergillus niger cellulases by combined ion exchange affinity chromatography  

SciTech Connect

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.

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

1987-02-05

194

Crystallization and preliminary crystallographic characterization of endo-polygalacturonase II from Aspergillus niger.  

PubMed

The endo-polygalacturonase II from Aspergillus niger has been crystallized from an ammonium sulfate solution by the hanging drop method. The crystals belong to the monoclinic space group P2(1), with cell dimensions a = 69.6 A, b = 152.6 A, c = 74.0 A and beta = 91.2 degrees with four molecules per asymmetric unit. The crystals diffract to at least 2.8 A resolution and are suitable for X-ray analysis. PMID:7932761

Schröter, K H; Arkema, A; Kester, H C; Visser, J; Dijkstra, B W

1994-10-21

195

Interaction of tannase from Aspergillus niger with polycations applied to its primary recovery.  

PubMed

The interaction of tannase (TAH) with chitosan, polyethyleneimine and Eudragit(®)E100 was studied. It was found that TAH selectively binds to these polycations (PC), probably due to the acid nature of the target protein. TAH could interact with these PC depending on the medium conditions. The effect of the interaction on the secondary and tertiary structure of TAH was assayed through circular dichroism and fluorescence spectroscopy. TAH was recovered from Aspergillus niger culture broth by means of precipitation and adsorption using chitosan. PMID:23706551

Durán, Luis V Rodríguez; Spelzini, Darío; Boeris, Valeria; Aguilar, Cristóbal N; Picó, Guillermo A

2013-04-29

196

Tannase enzyme production by entrapped cells of Aspergillus niger FETL FT3 in submerged culture system.  

PubMed

The ability of immobilized cell cultures of Aspergillus niger FETL FT3 to produce extracellular tannase was investigated. The production of enzyme was increased by entrapping the fungus in scouring mesh cubes compared to free cells. Using optimized parameters of six scouring mesh cubes and inoculum size of 1 × 10(6) spores/mL, the tannase production of 3.98 U/mL was obtained from the immobilized cells compared to free cells (2.81 U/mL). It was about 41.64% increment. The immobilized cultures exhibited significant tannase production stability of two repeated runs. PMID:21347668

Darah, I; Sumathi, G; Jain, K; Lim, S H

2011-02-24

197

The chemical mechanism of action of glucose oxidase from Aspergillus niger  

Microsoft Academic Search

Glucose oxidase from Aspergillus niger (EC 1.1.3.4) is able to catalyze the oxidation of -D-glucose with p-benzoquinone, methyl-1,4-benzoquinone, 1,2-naphthoquinone, 1,2-naphthoquinone-4-sulfonic acid, potassium ferricyanide, phenazine methosulfate, and 2,6-dichloroindophenol. In this work, the steady-state kinetic parameters, V\\u000a1\\/K\\u000a\\u000aB\\u000a, for reactions of these substrates were collected from pH 2.5–8. Further, the molecular models of the enzyme's active site were constructed for

Gerd Wohlfahrt; Svetlana Trivi?; Jasmina Zeremski; Draginja Peri?in; Vladimir Leskovac

2004-01-01

198

Stability and identification of active-site residues of carboxymethylcellulases from Aspergillus niger and Cellulomonas biazotea  

Microsoft Academic Search

Determination of the apparent pK\\u000a a's of purified carboxymethylcellulases fromAspergillus niger andCellulomonas biazotea at different temperatures and in the presence of dioxane indicated two side chain carboxyl groups which controlled the limiting\\u000a rate in both organisms. The thermostability of both enzymes slightly decreased with increasing pH from 5 to 7.5 but was unaffected\\u000a in the presence of 0.5 mmol\\/L Mn2+.

K. S. Siddiqui; M. J. Azhar; M. H. Rashid; M. I. Rajoka

1997-01-01

199

Microbial conversion of rare ginsenoside Rf to 20(S)-protopanaxatriol by Aspergillus niger.  

PubMed

In this study, rare ginsenoside Rf was transformed into 20(S)-protopanaxatriol (PPT(S)) by glycosidase from Aspergillus niger. By investing the reaction conditions, the optimal conditions were obtained, as follows: pH 5.0, temperature 55 degrees C, and substrate concentration 1.25 mmol/l. Under optimal conditions, PPT(S) (1.13 micromol) prepared from 1.25 mumol Rf showed a higher yield (90.4%). The enzymatic reaction was analyzed by reversed-phase HPLC, suggesting the transformation pathway: Rf-->Rh1(S)-->PPT(S). PMID:20057152

Liu, Lei; Gu, Li-Juan; Zhang, Dong-Liang; Wang, Zhen; Wang, Chun-Yan; Li, Zheng; Sung, Chang-Keun

2010-01-07

200

Cloning and characterization of oah , the gene encoding oxaloacetate hydrolase in Aspergillus niger  

Microsoft Academic Search

The enzyme oxaloacetate hydrolase (EC 3.7.1.1), which is involved in oxalate formation, was purified from Aspergillus niger. The native enzyme has a molecular mass of 360–440?kDa, and the denatured enzyme has a molecular mass of 39?kDa, as determined\\u000a by gel electrophoresis. Enzyme activity is maximal at pH?7.0 and 45?°C. The fraction containing the enzyme activity contained\\u000a at least five proteins.

H. Pedersen; C. Hjort; J. Nielsen

2000-01-01

201

Bilateral allergic fungal rhinosinusitis caused by Schizophillum commune and Aspergillus niger. A case report.  

PubMed

Schizophillum commune (S. commune) is a rare type of basidiomycetous fungus that has being reported as a cause of allergic fungal rhinosinusitis (AFRS), invasive type of fungal sinusitis and allergic bronchopulmonary mycosis (ABPM). However, it is believed that S. commune was often misdiagnosed to Aspergillus sp. We report a case of bilateral nasal polyps and maxillary, ethmoidal and sphenoidal involvement within the context of S. commune and Aspergillus niger associated AFRS. Our patient was suffering from a chronic disease with periods of remission and exacerbation and was treated successfully by a combination of surgical and antifungal treatment. In our experience, S. commune may be found frequently in patients with AFRS. AFRS, including the S. commune-associated type, usually runs a prolonged course and can affect any paranasal sinus. Surgical treatment alone is not sufficient and must be combined with medical treatment. PMID:19593982

Ahmed, Mohamed Khalifa; Ishino, Takashi; Takeno, Sachio; Hirakawa, Katsuhiro

2009-06-01

202

Gene Overexpression and Biochemical Characterization of the Biotechnologically Relevant Chlorogenic Acid Hydrolase from Aspergillus niger?  

PubMed Central

The full-length gene that encodes the chlorogenic acid hydrolase from Aspergillus niger CIRM BRFM 131 was cloned by PCR based on the genome of the strain A. niger CBS 513.88. The complete gene consists of 1,715 bp and codes for a deduced protein of 512 amino acids with a molecular mass of 55,264 Da and an acidic pI of 4.6. The gene was successfully cloned and overexpressed in A. niger to yield 1.25 g liter?1, i.e., 330-fold higher than the production of wild-type strain A. niger CIRM BRFM131. The histidine-tagged recombinant ChlE protein was purified to homogeneity via a single chromatography step, and its main biochemical properties were characterized. The molecular size of the protein checked by mass spectroscopy was 74,553 Da, suggesting the presence of glycosylation. ChlE is assembled in a tetrameric form with several acidic isoforms with pIs of around 4.55 and 5.2. Other characteristics, such as optimal pH and temperature, were found to be similar to those determined for the previously characterized chlorogenic acid hydrolase of A. niger CIRM BRFM 131. However, there was a significant temperature stability difference in favor of the recombinant protein. ChlE exhibits a catalytic efficiency of 12.5 × 106 M?1 s?1 toward chlorogenic acid (CGA), and its ability to release caffeic acid from CGA present in agricultural by-products such as apple marc and coffee pulp was clearly demonstrated, confirming the high potential of this enzyme.

Benoit, Isabelle; Asther, Michele; Bourne, Yves; Navarro, David; Canaan, Stephane; Lesage-Meessen, Laurence; Herweijer, Marga; Coutinho, Pedro M.; Asther, Marcel; Record, Eric

2007-01-01

203

Biosorption of Cr(VI) onto marine Aspergillus niger : experimental studies and pseudo-second order kinetics  

Microsoft Academic Search

The removal of hexavalent chromium from aqueous solution was studied in batch experiments using dead biomass of three different\\u000a species of marine Aspergillus after alkali treatment. All the cultures exhibited potential to remove Cr(VI), out of which, Aspergillus niger was found to be the most promising one. This culture was further studied employing variation in pH, temperature, metal ion\\u000a concentration

Yasmin Khambhaty; Kalpana Mody; Shaik Basha; Bhavanath Jha

2009-01-01

204

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

SciTech Connect

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

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

205

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

PubMed Central

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.

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, Noel N.M.E.; Roubos, Johannes A.; Nielsen, Jens; Baker, Scott E.

2011-01-01

206

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

SciTech Connect

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.

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

207

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

PubMed Central

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.

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

2011-01-01

208

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

SciTech Connect

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.

Zetelaki-Horvath, K.; Vas, K.

1981-01-01

209

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

PubMed

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

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

2011-11-01

210

Determination of adhesion between single Aspergillus niger spores in aqueous solutions using an atomic force microscope.  

PubMed

The interaction force between single cells in contact is of high interest in various interdisciplinary fields of biotechnology, for instance, in cultivation or biofilm formation. A method for the determination of adhesion forces between two single Aspergillus niger spores in different aqueous solutions was established in this study. Adhesion force distributions were determined at three different sodium chloride concentrations and two different pH values using an atomic force microscope (AFM). It was pointed out that adhesion data can be described by log-normal density functions, of which corresponding parameters have been estimated. Using the knowledge of distribution shape, the influence of the environmental condition on the mean values of adhesion force could be studied quantitatively. The highest value of 0.95 nN was observed at pH 2.5 and an ionic strength of 0.5 mol L(-1). Decreasing the ionic strength to 0.05 mol L(-1) decreases the adhesion force mean for about 25%. Increasing the pH value to pH 5 at a sodium chloride concentration of 0.154 mol L(-1) entails a decrease of adhesion from 0.88 to 0.56 nN. These results qualitatively agree with the absolute value of the expected surface potential of Aspergillus niger spores, which is much higher at pH 5 and should take more effect at lower concentrations of counterions. PMID:20387816

Wargenau, Andreas; Kwade, Arno

2010-07-01

211

Removal and recovery of uranium (VI) from aqueous solutions by immobilized Aspergillus niger powder beads.  

PubMed

The immobilized Aspergillus niger powder beads were obtained by entrapping nonviable A. niger powder into Ca-alginate gel. The effects of pH, contact time, initial uranium (VI) concentration and biomass dosage on the biosorption of uranium (VI) onto the beads from aqueous solutions were investigated in a batch system. Biosorption equilibrium data were agreeable with Langmuir isotherm model and the maximum biosorption capacity of the beads for uranium (VI) was estimated to be 649.4 mg/g at 30 °C. The biosorption kinetics followed the pseudo-second-order model and intraparticle diffusion equation. The variations in enthalpy (26.45 kJ/mol), entropy (0.167 kJ/mol K) and Gibbs free energy were calculated from the experimental data. SEM and EDS analysis indicated that the beads have strong adsorption capability for uranium (VI). The adsorbed uranium (VI) on the beads could be released with HNO(3) or HCl. The results showed that the immobilized A. niger powder beads had great potential for removing and recovering uranium (VI) from aqueous solutions. PMID:22580796

Ding, De-Xin; Tan, Xiang; Hu, Nan; Li, Guang-Yue; Wang, Yong-Dong; Tan, Yan

2012-05-15

212

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

PubMed Central

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.

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

213

Effective lead selection for improved protein production in Aspergillus niger based on integrated genomics.  

PubMed

The filamentous fungus Aspergillus niger is widely exploited for industrial production of enzymes and organic acids. An integrated genomics approach was developed to determine cellular responses of A. niger to protein production in well-controlled fermentations. Different protein extraction methods in combination with automated sample processing and protein identification allowed quantitative analysis of 898 proteins. Three different enzyme overproducing strains were compared to their isogenic fungal host strains. Clear differences in response to the amount and nature of the overproduced enzymes were observed. The corresponding genes of the differentially expressed proteins were studied using transcriptomics. Genes that were up-regulated both at the proteome and transcriptome level were selected as leads for generic strain improvement. Up-regulated proteins included proteins involved in carbon and nitrogen metabolism as well as (oxidative) stress response, and proteins involved in protein folding and endoplasmic reticulum-associated degradation (ERAD). Reduction of protein degradation through the removal of the ERAD factor doaA combined with overexpression of the oligosaccharyl transferase sttC in A. niger overproducing beta-glucuronidase (GUS) strains indeed resulted in a small increase in GUS expression. PMID:18824119

Jacobs, Denise I; Olsthoorn, Maurien M A; Maillet, Isabelle; Akeroyd, Michiel; Breestraat, Stefaan; Donkers, Serge; van der Hoeven, Rob A M; van den Hondel, Cees A M J J; Kooistra, Rolf; Lapointe, Thomas; Menke, Hildegard; Meulenberg, Rogier; Misset, Marijke; Müller, Wally H; van Peij, Noël N M E; Ram, Arthur; Rodriguez, Sabrina; Roelofs, Marc S; Roubos, Johannes A; van Tilborg, Marcel W E M; Verkleij, Arie J; Pel, Herman J; Stam, Hein; Sagt, Cees M J

2008-09-12

214

The Aspergillus niger multicopper oxidase family: analysis and overexpression of laccase-like encoding genes  

PubMed Central

Background Many filamentous fungal genomes contain complex groups of multicopper oxidase (MCO) coding genes that makes them a good source for new laccases with potential biotechnological interest. A bioinformatics analysis of the Aspergillus niger ATCC 1015 genome resulted in the identification of thirteen MCO genes. Ten of them were cloned and homologously overexpressed. Results A bioinformatic analysis of the A. niger ATCC 1015 genome revealed the presence of 13 MCO genes belonging to three different subfamilies on the basis of their phylogenetic relationships: ascomycete laccases, fungal pigment MCOs and fungal ferroxidases. According to in silico amino acid sequence analysis, the putative genes encoding for functional extracellular laccases (mcoA, mcoB, mcoC, mcoD, mcoE, mcoF, mcoG, mcoI, mcoJ and mcoM) were placed under the control of the glaA promoter and overexpressed in A. niger N593. Enzyme activity plate assays with several common laccase substrates showed that all genes are actually expressed and code for active MCOs. Interestingly, expressed enzymes show different substrate specificities. In addition, optimization of fungal pigment MCOs extracellular production was investigated. The performance of the widely used glucoamylase signal sequence (ssGlaA) in McoA secretion was studied. Results obtained suggest that ssGlaA do not yield higher levels of secreted McoA when compared to its native secretion signal. Also, McoB synthesis was investigated using different nitrogen sources in minimal medium liquid cultures. Higher yields of extracellular McoB were achieved with (NH4)2 tartrate. Conclusions Aspergillus niger is a good source of new laccases. The different substrate specificity observed in plate assays makes them interesting to be purified and biochemically compared. The homologous signal sequence of McoA has been shown to be a good choice for its extracellular overexpression. From the nitrogen sources tested (NH4)2 tartrate has been found to be the most appropriate for McoB production in A. niger.

2011-01-01

215

Enhanced itaconic acid production in Aspergillus niger using genetic modification and medium optimization  

PubMed Central

Background Aspergillus niger was selected as a host for producing itaconic acid due to its versatile and tolerant character in various growth environments, and its extremely high capacity of accumulating the precursor of itaconic acid: citric acid. Expressing the CAD gene from Aspergillus terreus opened the metabolic pathway towards itaconic acid in A. niger. In order to increase the production level, we continued by modifying its genome and optimizing cultivation media. Results Based on the results of previous transcriptomics studies and research from other groups, two genes : gpdA encoding the glyceraldehyde ?3-dehydrogenase (GPD) and hbd1 encoding a flavohemoglobin domain (HBD) were overexpressed in A. niger. Besides, new media were designed based on a reference medium for A. terreus. To analyze large numbers of cultures, we developed an approach for screening both fungal transformants and various media in 96-well micro-titer plates. The hbd1 transformants (HBD 2.2/2.5) did not improve itaconic acid titer while the gpdA transformant (GPD 4.3) decreased the itaconic acid production. Using 20 different media, copper was discovered to have a positive influence on itaconic acid production. Effects observed in the micro-titer plate screening were confirmed in controlled batch fermentation. Conclusions The performance of gpdA and hbd1 transformants was found not to be beneficial for itaconic acid production using the tested cultivation conditions. Medium optimization showed that, copper was positively correlated with improved itaconic acid production. Interestingly, the optimal conditions for itaconic acid clearly differ from conditions optimal for citric- and oxalic acid production.

2012-01-01

216

Infection of the cones and seeds of Welwitschia mirabilis by Aspergillus niger var. phoenicis in the Namib-Naukluft Park  

Microsoft Academic Search

Welwitschia mirabilis Hook. fil. is a unique and rare dioecious desert gymnosperm endemic to the Namib Desert. The female plants bear 90–100 megasporophylls, of which 50–60% may be fertile, but up to 80% of those fertile seeds may be infected by Aspergillus niger var. phoenicis. This contamination results in seed and seedling death, potentially negatively affecting recruitment of plants into

C. Whitaker; N. W. Pammenter; P. Berjak

2008-01-01

217

Decolorization and detoxification of Synozol red HF-6BN azo dye, by Aspergillus niger and Nigrospora sp  

PubMed Central

In the present investigation the fungi, Aspergillus niger and Nigrospora sp. were employed for decolorization of Synozol red HF-6BN. Decolorization study showed that Aspergillus niger and Nigrospora sp. were able to decolorize 88% and 96% Synozol red 6BN, respectively, in 24 days. It was also studied that 86% and 90% Synozol red containing of dye effluent was decolorized by Aspergillus niger and Nigrospora sp. after 28 days of incubation at room temperature. A fungal-based protein with relative molecular mass of 70 kDa was partially purified and examined for enzymatic characteristics. The enzyme exhibited highest activity at temperature ranging from 40-50°C and at pH=6.0. The enzyme activity was enhanced in the presence of metal cations. High performance liquid chromatography analysis confirmed that these fungal strains are capable to degrade Synozol red dye into metabolites. No zones of inhibition on agar plates and growth of Vigna radiata in the presence of dye extracted sample, indicated that the fungal degraded dye metabolites are nontoxic to beneficial micro-flora and plant growth. Aspergillus niger and Nigrospora sp. have promising potential in color removal from textile wastewater-containing azo dyes.

2013-01-01

218

Inhibition of Aspergillus niger on tea box packaging made of rubberwood treated with vapour of peppermint oil  

Microsoft Academic Search

Antifungal activities of rubberwood treated with vapour of peppermint oil against Aspergillus niger identified from rubberwood surfaces was investigated. The vapour of peppermint oil at 60°C was employed to determine the minimal inhibitory concentration (MIC using the concentration of substances between 100 and 900 µl ml-1). Peppermint oil exhibited high fungal activities with the MIC of 300µl ml-1 against the

Narumol Matan; Warasri Saengkrajang

219

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

Microsoft Academic Search

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

Jesper M Mogensen; Kristian F Nielsen; Robert A Samson; Jens C Frisvad; Ulf Thrane

2009-01-01

220

Modeling the mechanisms of glucose transport through the cell membrane of Aspergillus niger in submerged citric acid fermentation processes  

Microsoft Academic Search

Data from batch fermentations of citric acid producing Aspergillus niger cultures in shake flasks, loop and stirred tank bioreactors, were used to construct diffusion models for the transport of glucose. It was found that the mediated diffusion model does not reflect the relationship between the observed uptake rate and glucose concentration, nor for the lack of sensitivity to citrate. This

M. Papagianni; M. Mattey

2004-01-01

221

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

PubMed Central

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.

2009-01-01

222

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

PubMed

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

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

2012-09-14

223

Cytosolic streaming in vegetative mycelium and aerial structures of Aspergillus niger  

PubMed Central

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.

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

2013-01-01

224

Cellulase production by Trichoderma longi, Aspergillus niger and Saccharomyces cerevisae cultured on waste materials from orange.  

PubMed

The wastes materials from the sweet orange (Citrus sinensis) were used as substrate for the production of cellulase. The rind, the pericarp or albedo and the pulp were hydrolyzed by cellulolytic enzymes of Trichoderma longibrachiatum, Aspergillus niger and Saccharomyces cerevisiae after they were treated with alkali and steam. The amount of glucose released from the substrates following the secretion of cellulase by the three microorganisms was measured. The orange wastes released amounts of glucose ranging from 0.76-0.96 mg mL(-1) by Trichoderma longibrachiatum, 0.90-1.08 mg mL(-1) by A. niger and 0.60-0.76 mg mL(-1) by S. cerevisiae after five days of fermentation. The conditions of the fermentation were then varied to determine their effect on cellulase production. Fermentation parameters varied were time, pH, substrate concentration, temperature and inoculum size. After this, conditions that produced highest amounts of glucose were combined in an optimization experiment. Glucose production under optimized conditions were 0.94 mg mL(-1) by T. longibrachiatum, 0.83 mg mL(-1) by A. niger and 0.67 mg mL(-1) by S. cerevisae. The activity of the test organisms' cellulase against CMC on the orange wastes was also determined with T. longibrachiatum producing 3.86 mg mL(-1), A. niger 2.94 mg mL(-1) and S. cerevisiae 2.30 mg mL(-1) glucose amounts all from orange pulp. PMID:19137846

Omojasola, P F; Jilani, O P

2008-10-15

225

Morphology engineering - Osmolality and its effect on Aspergillus niger morphology and productivity  

PubMed Central

Background The filamentous fungus Aspergillus 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, ranging from dense spherical pellets to viscous mycelia depending on culture conditions. Optimal productivity correlates strongly with a specific morphological form, thus making high demands on process control. Results In about 50 2L stirred tank cultivations the influence of osmolality on A. niger morphology and productivity was investigated. The specific productivity of fructofuranosidase producing strain A. niger SKAn 1015 could be increased notably from 0.5 to 9 U mg-1 h-1 around eighteen fold, by increasing the culture broth osmolality by addition of sodium chloride. The specific productivity of glucoamylase producing strain A. niger AB1.13, could be elevated using the same procedure. An optimal producing osmolality was shown to exist well over the standard osmolality at about 3.2 osmol kg-1 depending on the strain. Fungal morphology of all cultivations was examined by microscope and characterized by digital image analysis. Particle shape parameters were combined to a dimensionless Morphology number, which enabled a comprehensive characterization of fungal morphology correlating closely with productivity. A novel method for determination of germination time in submerged cultivations by laser diffraction, introduced in this study, revealed a decelerated germination process with increasing osmolality. Conclusions Through the introduction of the versatile Morphology number, this study provides the means for a desirable characterization of fungal morphology and demonstrates its relation to productivity. Furthermore, osmolality as a fairly new parameter in process engineering is introduced and found to affect fungal morphology and productivity. Osmolality might provide an auspicious and reliable approach to increase the productivity in industrial processes. Because of the predictable behavior fungal morphology showed in dependence of osmolality, a customization of morphology for process needs seems feasible.

2011-01-01

226

pgaE encodes a fourth member of the endopolygalacturonase gene family from Aspergillus niger.  

PubMed

In the present study, the molecular and basic biochemical characterization of endopolygalacturonase E, the fourth Aspergillus niger N400 endopolygalacturonase, is reported. The entire endopolygalacturonase E gene consists of 1293 bp interrupted by three short introns (50, 50, and 59 bp, respectively) as concluded from the cDNA sequence. The deduced amino acid sequence comprises 378 residues that include 39 N-terminal amino acids of the prepropeptide. The calculated Mr and pI of the mature protein are 35,584 and 3.6, respectively. Compared with other endopolygalacturonases from A. niger N400, the mature protein endopolygalacturonase E has the highest sequence identity with endopolygalacturonase C (77.6%) followed by endopolygalacturonase I (57.6%) and endopolygalacturonase II (54.3%). For overproduction of endopolygalacturonase E, an A. niger multicopy strain was used that was transformed with a promoter gene fusion construct that directs expression from the glycolytic A. niger pyruvate kinase promoter. The enzyme was purified and characterized as an endopolygalacturonase based on product analysis after polygalacturonate hydrolysis and on bond cleavage frequencies of oligogalacturonates of different degree of polymerisation (n = 2-7). The pH optimum was 3.8. The Km and Vmax for polygalacturonate hydrolysis were 2.5 +/- 0.4 mg x ml(-1) and 1.3 +/- 0.2 microkat x mg(-1), respectively. A subsite map was calculated by the combination of the methods of Suganuma et al. [Suganuma, T., Matsuno, R., Ohnishi, M. & Hiromi, K. (1978) J. Biochem. (Tokyo) 84, 293-316] and Nitta et al. [Nitta, Y., Mizushima, M., Hiromi, K. & Ono, S. (1971) J. Biochem. (Tokyo) 69, 567-576]. This indicated that the enzyme was composed of at least five subsites. PMID:9492270

Parenicová, L; Benen, J A; Kester, H C; Visser, J

1998-01-15

227

In vitro interaction of terbinafine with itraconazole, fluconazole, amphotericin B and 5-flucytosine against Aspergillus spp  

Microsoft Academic Search

We investigated the in vitro interaction of terbinafine with itraconazole, fluconazole, ampho- tericin B and 5-flucytosine, against Aspergillus spp. We tested three isolates of Aspergillus fumi- gatus (one resistant to itraconazole), and two each of Aspergillus flavus, Aspergillus niger and Aspergillus terreus. We employed a broth microdilution-based method derived from an in vivo validated method capable of detecting itraconazole resistance

J. Mosquera; A. Sharp; C. B. Moore; P. A. Warn; D. W. Denning

2002-01-01

228

Occupational IgE sensitisation to phytase, a phosphatase derived from Aspergillus niger  

PubMed Central

OBJECTIVE: Phytase is a phosphatase derived from Aspergillus niger that enhances phosphate bioavailability in the gut, and therefore has been increasingly used as an animal feed additive since the early 1990s. The aim of this study was to assess whether work related respiratory symptoms among workers in a so called premix factory producing animal feed additives, could be due to type I (mediated by immunoglobulin E (IgE) allergic sensitisation to phytase. METHODS: Preparations of specific IgE against phytase as used in the factory were assessed by enzyme immunoassay (EIA) in serum samples of 11 exposed workers who regularly handled the enzyme, in 11 office and laboratory workers of the same plant (non-exposed internal controls), and in 19 laboratory animal workers as external controls. The factory workers also completed a questionnaire on common and work related respiratory symptoms. RESULTS: Depending on the cut off level in the EIA for IgE, and the preparation used as coated allergen, antiphytase sensitisation was found in one to four of the 19 external controls, in one to five of the 11 internal controls, and in four to 10 of the 11 exposed workers. Strongest IgE reactions were found in four exposed workers who reported work related respiratory symptoms, particularly wheezing, and in one internal control who possibly had become sensitised because the structure of the factory building did not preclude airborne exposure in the offices and corridors of the plant. Experiments with inhibition EIA for IgE showed that (a) phytase of another commercial source was only partially cross reactive with phytase as used in the premix factory, and (b) phytase used as an animal feed additive did not cross react with common mould extracts, except for extracts from the species of origin, Aspergillus niger. The amount of IgE binding phytase in Aspergillus niger was estimated to be between 0.1% and 1% of the extractable mould proteins. CONCLUSIONS: Phytase is a potentially important new occupational allergen causing specific IgE immune responses among exposed workers. Such IgE sensitisation could probably be the cause of work related asthmatic and other respiratory symptoms if no effective measures are taken to prevent airborne occupational exposure at sites where phytase is handled, particularly during addition of enzyme preparations to animal feed.  

Doekes, G.; Kamminga, N.; Helwegen, L.; Heederik, D.

1999-01-01

229

Enhanced production of Aspergillus niger laccase-like multicopper oxidases through mRNA optimization of the glucoamylase expression system.  

PubMed

In filamentous fungi, most of the strategies used for the improvement of protein yields have been based on an increase in the transcript levels of a target gene. Strategies focusing at the translational level have been also described, but are far less explored. Here the 5' untranslated sequence of the glaA mRNA, a widely used expression system for the expression of recombinant proteins, was modified by the introduction of different nucleotide elements that have positive role in the translation process. Five Aspergillus niger laccase-like multicopper oxidases (MCOs) coding genes were fused to the native glaA 5'UTR and the three synthetic versions (sUTR1, sUTR2, and sUTR3) as well, and placed under the control of the glucoamylase gene promoter. Afterwards, a total of 20 fungal transformations were done using A. niger N593 as a recipient strain and 50 transformants per transformation were isolated and analyzed. The result of the incorporation of the synthetic 5'UTRs on the overall productivity of the transformants was assessed, on one hand by monitoring the laccase activity of all the isolated transformants, and on the other hand by quantifying and comparing the activity of those secreting the highest level of each MCO. For this purpose, a high-throughput method for the screening and selection of the best producers was developed. Once the best transformants producing the highest yield of McoA, McoB, McoC, McoD, and McoJ laccases were selected, their production level was quantified in supernatants of liquid cultures. The results obtained in this work indicate that modifications in the native glaA 5'UTR can lead to improvements in protein yields. PMID:22949265

Tamayo-Ramos, Juan Antonio; Barends, Sharief; de Lange, Dennis; de Jel, Annemarie; Verhaert, Raymond; de Graaff, Leo

2012-09-20

230

Optimization of glucose oxidase production by Aspergillus niger using genetic- and process-engineering techniques.  

PubMed

Wild-type Aspergillus niger NRRL-3 was transformed with multiple copies of the glucose oxidase structural gene (god). The gene was placed under the control of the gpdA promoter of A. nidulans. For more efficient secretion the alpha-amylase signal peptide from A. oryzae was inserted in front of god. Compared to the wild type, the recombinant strain NRRL-3 (GOD3-18) produced up to four times more extracellular glucose oxidase under identical culture conditions. Addition of yeast extract (2 gl-1) to a mineral salts medium containing only glucose as carbon source increased volumetric and specific extracellular glucose oxidase activities by 130% and 50% respectively. With the same medium composition and inoculum size, volumetric and specific extracellular glucose oxidase activities increased more than ten times in bioreactor cultivations compared to shake-flask cultures. PMID:8590664

Hellmuth, K; Pluschkell, S; Jung, J K; Ruttkowski, E; Rinas, U

1995-11-01

231

Pectinase production by Aspergillus niger using wastewater in solid state fermentation for eliciting plant disease resistance.  

PubMed

An elicitor of plant disease resistance, pectinase, was produced by solid state fermentation with Aspergillus niger. Sugar beet pulp was used as carbon source and the wastewater from monosodium glutamate production was used as nitrogen and water source. The composition of the fermentation medium was: 11 ml concentrated wastewater (containing NH3-N 38.2 mg/ml), sugar beet pulp 10 g, Na2HPO4.12H2O 0.2 g, KH2PO4 0.04 g in a 500 ml Erlenmeyer flask. The fermentation temperature was 30 degrees C and the relative humidity of the air was 75-90%. The maximum production of pectinase was reached after 96 h cultivation. The crude pectinase extracted from the fermented materials could elicit disease resistance in cucumber and tomato seedlings. PMID:15207294

Bai, Z H; Zhang, H X; Qi, H Y; Peng, X W; Li, B J

2004-10-01

232

Naphtho-?-pyrones from Endophyte Aspergillus niger occurring in the liverwort Heteroscyphus tener (Steph.) Schiffn.  

PubMed

Bioactivity-guided fractionation of the cytotoxic extract of Aspergillus niger, an endophytic fungus from the Chinese liverwort Heteroscyphus tener (Steph.) Schiffn., afforded five new naphtho-?-pyrones, rubrofusarin-6-O-?-D-ribofuranoside (1), (R)-10-(3-succinimidyl)-TMC-256A1 (2), asperpyrone E (3), isoaurasperone A (4), and isoaurasperone F (5), as well as four known ones, dianhydroaurasperone C (6), aurasperone D (7), asperpyrone D (8), and asperpyrone A (9), together with a cytotoxic cyclic pentapeptide, malformin A1 (10). Their structures were determined by extensive spectroscopic analysis. The absolute configurations of dimeric naphtho-?-pyrones 3-9 were also determined by analysis of their respective CD spectra. PMID:23847065

Li, Xiao-Bin; Xie, Fei; Liu, Shan-Shan; Li, Ying; Zhou, Jin-Chuan; Liu, Yong-Qing; Yuan, Hui-Qing; Lou, Hong-Xiang

2013-07-01

233

Production of a new type of acid carboxypeptidase of molds of the Aspergillus niger group.  

PubMed

The ability of 88 fungi, which had been obtained as high-potency strains for acid proteinase production, to produce a new type of acid carboxypeptidase (having on optimal pH of about 3 for hydrolysis of benzyloxycarbonyl-glutamyltyrosine) in surface koji culture was determined. Among the aspergilli, substantial amounts of this new acid carboxypeptidase were produced by Aspergillus saitoi, A. usamii, A. awamori, A. inuii, and A. niger. Maximum yields of acid carboxypeptidase per gram of substrate were obtained by submerged culture in a medium containing 0.9% defatted soybean and 0.6% wheat bran. However, the maximum enzyme concentration per milliliter was obtained with a medium containing 3% defatted soybean and 2% wheat bran. The terminal pH could be controlled by varying the concentrations of soybean oil meal and wheat bran. The maximum enzyme production was reached after 4 days or more at 30 C. PMID:4796163

Ichishima, E; Yamane, A; Nitta, T; Kinoshita, M; Nikkuni, S

1973-09-01

234

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

PubMed

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

González-Pombo, Paula; Fariña, Laura; Carrau, Francisco; Batista-Viera, Francisco; Brena, Beatriz M

2013-07-29

235

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

PubMed

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

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

2004-07-01

236

Statistical optimization for tannase production from Aspergillus niger under submerged fermentation.  

PubMed

Statistically based experimental design was employed for the optimization of fermentation conditions for maximum production of enzyme tannase from Aspergillus niger. Central composite rotatable design (CCRD) falling under response surface methodology (RSM) was used. Based on the results of 'one-at-a-time' approach in submerged fermentation, the most influencing factors for tannase production from A. niger were concentrations of tannic acid and sodium nitrate, agitation rate and incubation period. Hence, to achieve the maximum yield of tannase, interaction of these factors was studied at optimum production pH of 5.0 by RSM. The optimum values of parameters obtained through RSM were 5% tannic acid, 0.8% sodium nitrate, 5.0 pH, 5 × 10(7) spores/50mL inoculum density, 150 rpm agitation and incubation period of 48 h which resulted in production of 19.7 UmL(-1) of the enzyme. This activity was almost double as compared to the amount obtained by 'one-at-a-time' approach (9.8 UmL(-1)). PMID:23100655

Sharma, S; Agarwal, L; Saxena, R K

2007-07-08

237

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

NASA Astrophysics Data System (ADS)

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.

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

238

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

PubMed

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

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

2006-02-21

239

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

PubMed

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

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

2005-08-19

240

Metabolic pathway reconstruction of eugenol to vanillin bioconversion in Aspergillus niger  

PubMed Central

Identification of missing genes or proteins participating in the metabolic pathways as enzymes are of great interest. One such class of pathway is involved in the eugenol to vanillin bioconversion. Our goal is to develop an integral approach for identifying the topology of a reference or known pathway in other organism. We successfully identify the missing enzymes and then reconstruct the vanillin biosynthetic pathway in Aspergillus niger. The procedure combines enzyme sequence similarity searched through BLAST homology search and orthologs detection through COG & KEGG databases. Conservation of protein domains and motifs was searched through CDD, PFAM & PROSITE databases. Predictions regarding how proteins act in pathway were validated experimentally and also compared with reported data. The bioconversion of vanillin was screened on UV-TLC plates and later confirmed through GC and GC-MS techniques. We applied a procedure for identifying missing enzymes on the basis of conserved functional motifs and later reconstruct the metabolic pathway in target organism. Using the vanillin biosynthetic pathway of Pseudomonas fluorescens as a case study, we indicate how this approach can be used to reconstruct the reference pathway in A. niger and later results were experimentally validated through chromatography and spectroscopy techniques.

Srivastava, Suchita; Luqman, Suaib; Khan, Feroz; Chanotiya, Chandan S; Darokar, Mahendra P

2010-01-01

241

Eosinophilic pneumonia caused by Aspergillus niger: is oral cleansing with amphotericin B efficacious in preventing relapse of allergic pneumonitis?  

PubMed

Eosinophilic pneumonia was confirmed by bronchoalveolar lavage fluid examination and transbronchial lung biopsy. Aspergillus niger was cultured from the patient's pharyngeal swab and bronchoalveolar lavage fluid. Inhalation bronchoprovocation test with A. niger antigen was positive. Although the patient's condition improved promptly with 10 mg/day prednisolone administration, dry cough recurred approximately 2 months after completion of this therapy. Severe coughing disappeared on oral cleansing with 300 mg/day amphotericin B, and he recovered completely on 100 mg/day amphotericin B administration. Oral cleansing with amphotericin B may be efficacious in preventing relapses of eosinophilic pneumonia caused by allergic reaction to fungal antigen. PMID:19191146

Ogawa, Haruhiko; Fujimura, Masaki; Tofuku, Yohei; Kitagawa, Masanobu

2009-02-01

242

Effect of Aspergillus niger on shoot emergence and vine development in field-sown yams ( Dioscorea spp.) and rot development under long-term storage conditions  

Microsoft Academic Search

The effects of infection of seed yam by Aspergillus niger on shoot emergence and vine development were investigated in three yam species. Shoot emergence was particularly poor in D. esculenta; this was attributed to a greater susceptibility to A. niger due to the relatively smaller size of the tuber, less compact inner tissue and thinner periderm in the species. Reductions

M. O. Otusanya; M. J. Jeger

1996-01-01

243

[Aspergillus spp. isolations from respiratory tract samples in Trakya University Hospital].  

PubMed

The characteristics of cases diagnosed as aspergillosis and Aspergillus spp. strains isolated from the respiratory tract samples in Mycology Laboratory of Trakya University Hospital between January 2002 and May 2006 were investigated. In this period, 137 bronchoalveolar lavages, 95 sputum, nine tracheal aspirates, three lung biopsies and one bronchial biopsy of 85 patients were processed. The samples were incubated in 25 degrees C and 35 degrees C media by culturing on brain heart infusion agar with blood and Sabouraud dextrose agar. Presence of leucocytes and fungal structures were searched in the smear stained by Gram and Giemsa. The patient was defined as probable aspergillosis case, if he/she patient had clinical findings, lung infiltration or fungus ball radiologically, at least one risk factor predisposing to aspergillosis and isolation of Aspergillus spp. in lower respiratory tract samples without finding of other nonmycotic infection. Of 22 patients isolated Aspergillus spp., 13, six, two, one were internalized in chest diseases, haemotology, neurosurgery and oncology clinics, respectively. Seven positive cultures were considered as findings of aspergillosis. Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger were isolated in three, two, and two patients, respectively. Fungal structures were detected in only one sample in the direct microscopical examination. Ages of seven patients, five were males and two were females, were between 15 and 60. Predisposing risk factors were acute leukemia in six patients and lung cancer in one patient. Five patients were neutropenic and one was neutrophylic. Fungus ball was detected in radiological imaging of one patient, had a pulmonary cavitary lesion. Conventional amphotericine B was used in their therapies. Antifungal agents were switched to caspofungin and itraconazole in two and one patients, respectively. Three patients died in four weeks after isolation of Aspergillus spp. Aspergillosis cases were not high in our hospital because of absence of transplantation center for bone marrow or solid organ. PMID:17602344

Gürcan, Saban; Demir, Muzaffer; Altiay, Gündeniz; Tikve?li, Melek; Kiliç, Haluk; Otkun, Metin

2007-01-01

244

Niger.  

PubMed

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

1987-06-01

245

Gamma radiation induced mutagenesis in Aspergillus niger to enhance its microbial fermentation activity for industrial enzyme production  

Microsoft Academic Search

?- and ?-Galactosidases find application in food processing, health and nutrition. Aspergillus niger is one of the potent producer of these enzymes and was genotypically improved using gamma-ray induced mutagenesis. The mutant-derivative\\u000a produced two-fold higher ?- and ?-galactosidases. For testing genetic variability and its relationship with phenotypic properties\\u000a of the two organisms, DNA samples of the mutant and parental strains

M. Siddique Awan; Nabila Tabbasam; N. Ayub; M. E. Babar; Shahid Mahboob Rana; M. I. Rajoka

2011-01-01

246

Response surface optimization of medium components for citric acid production by Aspergillus niger NRRL 567 grown in peat moss  

Microsoft Academic Search

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 30g\\/kg dry peat moss (DPM) enhanced

Suzelle Barrington; Jin-Woo Kim

2008-01-01

247

Coffee husk: an inexpensive substrate for production of citric acid by Aspergillus niger in a solid-state fermentation system  

Microsoft Academic Search

Aspergillus niger CFTRI 30 produced 1.3 g citric acid\\/10 g dry coffee husk in 72 h solid-state fermentation when the substrate was moistened with 0.075 M NaOH solution. Production was increased by 17% by adding a mixture of iron, copper and zinc to the medium but enrichment of the moist solid medium with (NH4)2SO4, sucrose or any of four enzymes

V. S. Shankaranand; B. K. Lonsane

1994-01-01

248

Differential expression of three alpha-galactosidase genes and a single beta-galactosidase gene from Aspergillus niger  

Microsoft Academic Search

A gene encoding a third a-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

Vries de R. P; Broeck van den H. C; ESTER DEKKERS; PALOMA MANZANARES; Graaff de L. H; JAAP VISSER

1999-01-01

249

Nucleotide sequence of the Aspergillus niger trpC gene: structural relationship with analogous genes of other organisms  

Microsoft Academic Search

The nucleotide sequence of the Aspergillus niger tryptophan C (trpC) gene was determined. Northern hybridization and S1-mapping experiments showed the presence of a 2.6 kb trpC poly(A)+ RNA with two very short (5 and 6 nucleotides) noncoding 5'-regions. Comparison of the predicted amino acid sequence with that of trp gene proteins of pro- and eukaryotic organisms revealed three functional domains

Ton Kos; Anneke Kuijvenhoven; Hanny G. M. Hessing; Peter H. Pouwels; Cees A. M. J. J. Hondel

1988-01-01

250

The Aspergillus niger (ficuum) aphA gene encodes a pH 6.0-optimum acid phosphatase  

Microsoft Academic Search

We have used the Aspergillus niger (An) aphA gene as a probe and cloned the A. ficuum (Af) SRRC 265 gene encoding an extracellular pH 6.0-optimum acid phosphatase (APase6) from a genomic library. The identity of the AfaphA gene was confirmed and its nucleotide (nt) sequence verified by comparing its deduced amino acid (aa) sequence to that of purified Af

Edward J. Mullaney; Catherine B. Daly; Kenneth C. Ehrlich; Abul H. J. Ullah

1995-01-01

251

Biosorption of Colour-Imparting Substances in Biologically Treated Pulp Mill Effluent Using Aspergillus niger Fungal Biomass  

Microsoft Academic Search

Biosorption has potential to be an economical colour removal technology. As such, the colour removal potential of inactivated\\u000a Aspergillus niger biomass was investigated for the treatment of activated sludge-treated pulp mill effluent from a northern bleached softwood\\u000a kraft mill. Biomass pretreatment methods, effects of initial pH of the effluent and preparative biomass washing methods were\\u000a examined. The most effective pretreatment

Sarah Grainger; George Yuzhu Fu; Eric R. Hall

2011-01-01

252

Influence of antifungal pre-treatment in preparing test mycelium on MIC values of several antifungal agents against Aspergillus niger  

Microsoft Academic Search

Antifungal activity of two imidazoles (miconazole and ketoconazole) and one polyene (amphotericin B) was evaluated using an\\u000a automatic growth analysis system. Spores ofAspergillus niger were inoculated on the polylysine-coated glass bottom of a culture vessel. A colony formed in liquid medium was exposed to\\u000a an antifungal agent and subsequently washed. Based on the dynamic growth rate of a test hypha

Jong-Chul Parkll; Kosuke Takatori; Hun-Jun Lee; Hideaki Matsuoka; Hiroshi Kurata

1996-01-01

253

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

PubMed

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

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

2011-10-11

254

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

PubMed

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% NaNO(3), 0.1% KH(2)PO(4), 0.05% MgSO(4) ·7H(2)O, 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 × 10(6)?spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment. PMID:21826273

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

2011-07-28

255

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

PubMed Central

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.

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

2011-01-01

256

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...

257

Gene transfer between different Trichoderma species and Aspergillus niger through intergeneric protoplast fusion to convert ground rice straw to citric acid and cellulases.  

PubMed

Single-stage direct bioconversion of cellulosic materials to citric acid using intergeneric hybrids obtained from three different Trichoderma species and Aspergillus niger was carried out. The recent results were obtained on the basis of either resistance or sensitivity to one or more of five metal ions, two catabolite repressors, and five antifungal agents, which were used in this study at different concentrations. Sixty-six fusants were isolated after using the three intergeneric protoplast fusion experiments, belonging to two types of intergeneric fusants. Fusants of the first type are heterokaryons (35 fusants). On the other hand, those of the second type are haploids (31 fusants), i.e., they were stable. The present study can be successfully applied in the construction of 14 new genetic fusants, which produced at least 100% more citric acid than the citric acid producer strain A. niger. Out of the fusants, three (1/18, 2/13 and 2/15) showed about a threefold increase of citric acid production in comparison with the parent A. niger strain. Furthermore, studies on DNA content showed that this finding may be submitted on the evidence that citric acid and cellulases production was not correlated with DNA content; however, the productivity depends on specific DNA content. PMID:17159236

El-Bondkly, Ahmed M

2006-11-01

258

Systemic analysis of the response of Aspergillus niger to ambient pH  

PubMed Central

Background The filamentous fungus Aspergillus niger is an exceptionally efficient producer of organic acids, which is one of the reasons for its relevance to industrial processes and commercial importance. While it is known that the mechanisms regulating this production are tied to the levels of ambient pH, the reasons and mechanisms for this are poorly understood. Methods To cast light on the connection between extracellular pH and acid production, we integrate results from two genome-based strategies: A novel method of genome-scale modeling of the response, and transcriptome analysis across three levels of pH. Results With genome scale modeling with an optimization for extracellular proton-production, it was possible to reproduce the preferred pH levels for citrate and oxalate. Transcriptome analysis and clustering expanded upon these results and allowed the identification of 162 clusters with distinct transcription patterns across the different pH-levels examined. New and previously described pH-dependent cis-acting promoter elements were identified. Combining transcriptome data with genomic coordinates identified four pH-regulated secondary metabolite gene clusters. Integration of regulatory profiles with functional genomics led to the identification of candidate genes for all steps of the pal/pacC pH signalling pathway. Conclusions The combination of genome-scale modeling with comparative genomics and transcriptome analysis has provided systems-wide insights into the evolution of highly efficient acidification as well as production process applicable knowledge on the transcriptional regulation of pH response in the industrially important A. niger. It has also made clear that filamentous fungi have evolved to employ several offensive strategies for out-competing rival organisms.

Andersen, Mikael R; Lehmann, Linda; Nielsen, Jens

2009-01-01

259

Structural Features of Sugars That Trigger or Support Conidial Germination in the Filamentous Fungus Aspergillus niger.  

PubMed

The asexual spores (conidia) of Aspergillus niger germinate to produce hyphae under appropriate conditions. Germination is initiated by conidial swelling and mobilization of internal carbon and energy stores, followed by polarization and emergence of a hyphal germ tube. The effects of different pyranose sugars, all analogues of d-glucose, on the germination of A. niger conidia were explored, and we define germination as the transition from a dormant conidium into a germling. Within germination, we distinguish two distinct stages, the initial swelling of the conidium and subsequent polarized growth. The stage of conidial swelling requires a germination trigger, which we define as a compound that is sensed by the conidium and which leads to catabolism of d-trehalose and isotropic growth. Sugars that triggered germination and outgrowth included d-glucose, d-mannose, and d-xylose. Sugars that triggered germination but did not support subsequent outgrowth included d-tagatose, d-lyxose, and 2-deoxy-d-glucose. Nontriggering sugars included d-galactose, l-glucose, and d-arabinose. Certain nontriggering sugars, including d-galactose, supported outgrowth if added in the presence of a complementary triggering sugar. This division of functions indicates that sugars are involved in two separate events in germination, triggering and subsequent outgrowth, and the structural features of sugars that support each, both, or none of these events are discussed. We also present data on the uptake of sugars during the germination process and discuss possible mechanisms of triggering in the absence of apparent sugar uptake during the initial swelling of conidia. PMID:23995938

Hayer, Kimran; Stratford, Malcolm; Archer, David B

2013-08-30

260

Multi-objective optimization in Aspergillus niger fermentation for selective product enhancement.  

PubMed

A multi-objective optimization formulation that reflects the multi-substrate optimization in a multi-product fermentation is proposed in this work. This formulation includes the application of epsilon-constraint to generate the trade-off solution for the enhancement of one selective product in a multi-product fermentation, with simultaneous minimization of the other product within a threshold limit. The formulation has been applied to the fed-batch fermentation of Aspergillus niger that produces a number of enzymes during the course of fermentation, and of these, catalase and protease enzyme expression have been chosen as the enzymes of interest. Also, this proposed formulation has been applied in the environment of three control variables, i.e. the feed rates of sucrose, nitrogen source and oxygen and a set of trade-off solutions have been generated to develop the pareto-optimal curve. We have developed and experimentally evaluated the optimal control profiles for multiple substrate feed additions in the fed-batch fermentation of A. niger to maximize catalase expression along with protease expression within a threshold limit and vice versa. An increase of about 70% final catalase and 31% final protease compared to conventional fed-batch cultivation were obtained. Novel methods of oxygen supply through liquid-phase H2O2 addition have been used with a view to overcome limitations of aeration due to high gas-liquid transport resistance. The multi-objective optimization problem involved linearly appearing control variables and the decision space is constrained by state and end point constraints. The proposed multi-objective optimization is solved by differential evolution algorithm, a relatively superior population-based stochastic optimization strategy. PMID:16217656

Mandal, Chaitali; Gudi, Ravindra D; Suraishkumar, G K

2005-11-16

261

On the safety of a new generation of DSM Aspergillus niger enzyme production strains.  

PubMed

Consumers safety of enzyme preparations is determined by three variables: the producing organism, the raw materials used in the production, and the production process itself. The latter one is embedded in current Good Manufacturing Practice (cGMP) and Hazard Analysis of Critical Control Points (HACCP); therefore the safety focus can be directed to raw materials and the producing organism. In this paper, we describe the use of novel genetically modified strains of Aspergillus niger-made by a design and build strategy-from a lineage of classically improved strains with a history of safe use in enzyme production. The specifics of the host strain allow for integration and over-expression of any gene of interest at a targeted integration site implying that the rest of the host genome is not affected by this integration. Furthermore due to the fact that the newly integrated gene copies are put under the genetic regulation of the host's own glucoamylase promoter, the recipe of the production process of any new production strain can be kept constant with respect to the raw materials composition. Consequently the safety of a new enzyme product from these novel genetically modified strains is determined by the background of the production organism. The use of a strain with a history of safe use and targeted integration according to the concept described above has consequences for the safety studies on the final product. If a known enzymatic activity is over-expressed the safety of a new enzyme preparation is covered by the results of the safety studies performed for other strains from this specific Aspergillus niger strain lineage. In this paper an overview is given on the available toxicity tests with these strains. We conclude that for new enzyme products produced with strains from this lineage using the design and build technology no new sub-acute/chronic oral toxicity studies are needed. This also has the benefit that no longer test animals are needed to demonstrate the safety of products produced by these strains. PMID:12878051

van Dijck, Piet W M; Selten, Gerard C M; Hempenius, Rixta A

2003-08-01

262

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

PubMed

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

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

263

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

PubMed

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

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

2012-10-30

264

Biotransformation of 20(S)-protopanaxadiol by Aspergillus niger AS 3.1858.  

PubMed

The biotransformation of 20(S)-protopanaxadiol (1) by Aspergillus niger AS 3.1858 was conducted. Seven metabolites 26-hydroxyl-20(S)-protopanaxadiol (2); 23, 24-en-25-hydroxyl-20(S)-protopanaxadiol (3); 25, 26-en-20(S)-protopanaxadiol (4); (E)-20, 22-en-25-hydroxyl-20(S)-protopanaxadiol (5); 25, 26-en-24(R)-hydroxyl-20(S)-protopanaxadiol (6); 25, 26-en-24(S)-hydroxyl-20(S)-protopanaxadiol (7); and 23, 24-en-25-ethoxyl-20(S)-protopanaxadiol (8) were afforded. Among them, 6, 7, and 8 are new compounds. The chemical structures of these metabolites were elucidated based on extensive spectral data including 2D NMR and HRMS. In addition, the cytotoxicity of substrate and all transformed products was evaluated by MTT assay using a panel of seven human tumor cell lines (Du-145, Hela, K562, K562/ADR, SH-SY5Y, HepG2, and MCF-7 cells) and one normal cell line Vero. PMID:24096145

Chen, Guangtong; Yang, Xue; Li, Jianlin; Ge, Hongjuan; Song, Yan; Ren, Jie

2013-10-03

265

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

PubMed

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

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

2012-02-09

266

[Mixed invasive fungal infection due to Rhizomucor pusillus and Aspergillus niger in an immunocompetent patient.  

PubMed

BACKGROUND: Mucormycosis infections are rare in immunocompetent patients, and very few cases of mucormycosis associated with aspergillosis in non-haematological patients have been reported. CASE REPORT: A 17-year-old male, immunocompetent and without any previously known risk factors, was admitted to hospital due to a seizure episode 11 days after a motorcycle accident. He had a complicated clinical course as he had a mixed invasive fungal infection with pulmonary involvement due to Aspergillus niger and disseminated mucormycosis due to Rhizomucor pusillus (histopathological and microbiological diagnosis in several non-contiguous sites). He was treated with liposomal amphotericin B for 7 weeks (total cumulative dose>10g) and required several surgical operations. The patient survived and was discharged from ICU after 5 months and multiple complications. CONCLUSIONS: Treatment with liposomal amphotericin B and aggressive surgical management achieved the eradication of a mixed invasive fungal infection. However, we emphasise the need to maintain a higher level of clinical suspicion and to perform microbiological techniques for early diagnosis of invasive fungal infections in non-immunocompromised patients, in order to prevent spread of the disease and the poor prognosis associated with it. PMID:23583263

Pozo-Laderas, Juan Carlos; Pontes-Moreno, Antonio; Robles-Arista, Juan Carlos; Bautista-Rodriguez, M Dolores; Candau-Alvarez, Alberto; Caro-Cuenca, Maria Teresa; Linares-Sicilia, María José

2013-04-11

267

Biodegradation of pharmaceuticals by Rhodococcus rhodochrous and Aspergillus niger by co-metabolism.  

PubMed

This work investigated the possible fate of pharmaceuticals in the environment that are known to be resistant to biodegradation. A co-metabolism approach, adding a readily degradable carbon source, was used to study the biodegradation of some pharmaceuticals. The pharmaceuticals selected were all known to be micro pollutants and frequently used by humans. The microorganisms used primarily were Rhodococcus rhodochrous, known to co-metabolize difficult to degrade hydrocarbons and Aspergillus niger. Because of the long periods of time required for the degradation experiments after growth had reached the stationary phase, it was found to be necessary to correct for water loss from the media. Co-metabolism of carbamazepine, sulfamethizole and sulfamethoxazole was observed and as much as 20% of these compounds could be removed. Small amounts of stable metabolites were observed during the degradation of some of these drugs and these were different from the metabolites obtained from abiotic degradation. A metabolite arising from the biodegradation of sulfamethoxazole by R.rhodochrous was identified. PMID:20089297

Gauthier, Hervé; Yargeau, Viviane; Cooper, David G

2010-01-20

268

Gluconate accumulation and enzyme activities with extremely nitrogen-limited surface cultures of Aspergillus niger.  

PubMed

Batch cultures of Aspergillus niger grown from conidia on a medium with high C/N ratio accumulated gluconate from glucose with a yield of 57%. During almost the whole time of accumulation there was no net synthesis of total protein in the mycelium but the activity per flask and the specific activity of glucose oxidase (EC 1.1.3.4) in mycelial extracts increased whereas both values decreased for glucose dehydrogenase (EC 1.1.99.10) 'gluconate 6-phosphatase' (cf. EC 3.1.3.1, 3.1.3.2), gluconokinase (EC 2.7.1.12), glucose 6-phosphate and phosphogluconate dehydrogenases (EC 1.1.1.49, EC 1.1.1.44), phosphoglucomutase (EC 2.7.5.1), and most enzymes of the Embden-Meyerhof pathway and the tricarboxylic acid cycle. Gluconate dehydratase (EC 4.2.1.39), gluconate dehydrogenase (EC 1.1.99.3) and enzymes of the Entner-Doudoroff pathway could not be detected. By cycloheximide the increase of glucose oxidase activity was inhibited. It is concluded that the high yield of gluconate was due mainly to the net (de novo) synthesis of glucose oxidase which occurred during protein turnover after the exhaustion of the nitrogen source, and which was not accompanied by a net synthesis of the other enzymes investigated. Some gluconate may also have been formed by hydrolytic cleavage of gluconate 6-phosphate. PMID:3013115

Müller, H M

1986-03-01

269

Differential properties of Aspergillus niger tannase produced under solid-state and submerged fermentations.  

PubMed

Significant differences on structure, stability, and catalytic properties of tannase were found when this enzyme was produced under solid-state and submerged fermentations (SSF and SmF) by Aspergillus niger. The specific activity was 5.5 times higher on SSF than in SmF. Significant differences in isoelectric points of tannases were found. The pH optima for both types of enzyme was found at 6 and the pH stability of SSF and SmF tannase were at 6 and 5-8, respectively. The optimal temperature range was from 50 to 60 °C for SmF tannase and 60 °C for SSF tannase, and both enzyme types showed tolerance to high temperatures (60-70 °C). The SSF tannase showed a major specificity for methyl gallate substrate while SmF tannase for tannic acid. All metal ions tested, had an activity inhibition from 30-46% on SSF tannase. SDS-PAGE analysis as well as gel localization studies of both SSF and SmF purified tannases showed a single band with a molecular weight of 102 and 105 kDa, respectively. Different levels of glycosylation were found among SSF and SmF purified tannases. This is the first report about structural differences among tannase produced under SSF and SmF and this study provides basis for explanation of the stability and catalytic differences observed previously for this two tannase types. PMID:21503777

Renovato, Jaqueline; Gutiérrez-Sánchez, Gerardo; Rodríguez-Durán, Luis V; Bergman, Carl; Rodríguez, Raúl; Aguilar, Cristóbal Noe

2011-04-19

270

On the origin of the electrostatic surface potential of Aspergillus niger spores in acidic environments.  

PubMed

The electrostatic surface potential of fungal spores is generally regarded as potentially influencing spore aggregation and pellet formation in submerged cultures of filamentous fungi. Spores of Aspergillus niger are typically characterized by negative zeta potentials over a wide range of pH values. In this study, this particular behavior is ascribed to the presence of an extensive melanin coating. It is proposed on the basis of zeta potential and pigment extraction experiments that this outermost layer affects the pH-dependent surface potential in two manners: (i) by the addition of negative charges to the spore surface and (ii) by the pH-dependent release of melanin pigment. Chemical analyses revealed that deprotonation of melanin-bound carboxyl groups is most probably responsible for pigment release under acidic conditions. These findings were incorporated into a simple model which has the ability to qualitatively explain the results of zeta potential experiments and, moreover, to provide the basis for quantitative investigations on the role of electrostatics in spore aggregation. PMID:21835241

Wargenau, Andreas; Fleissner, André; Bolten, Christoph Josef; Rohde, Manfred; Kampen, Ingo; Kwade, Arno

2011-07-29

271

Cloning, characterization, and expression of two alpha-amylase genes from Aspergillus niger var. awamori.  

PubMed

Using synthetic oligonucleotide probes, we cloned genomic DNA sequences encoding an alpha-amylase gene from Aspergillus niger var. awamori (A. awamori) on a 5.8 kb EcoRI fragment. Hybridization experiments, using a portion of this cloned fragment to probe DNA from A. awamori, suggested the presence of two alpha-amylase gene copies which were subsequently cloned as 7 kb (designated as amyA) and 4 kb (amyB) HindIII fragments. DNA sequence analysis of the amyA and amyB genes revealed the following: (1) Both genes are arranged as nine exons and eight introns; (2) The nucleotide sequences of amyA and amyB are identical throughout all but the last few nucleotides of their respective coding regions; (3) The amyA and amyB genes from A. awamori share extensive homology (greater than or equal to 98% identity) with the genes encoding Taka-amylase from A. oryzae. In order to test whether both amyA and amyB were functional in the genome, we constructed vectors containing gene fusions of either amyA and amyB to bovine prochymosin cDNA and used these vectors to transform A. awamori. Transformants which contained either the amyA- or amyB-prochymosin gene fusions produced extracellular chymosin, suggesting that both genes are functional. PMID:2340591

Korman, D R; Bayliss, F T; Barnett, C C; Carmona, C L; Kodama, K H; Royer, T J; Thompson, S A; Ward, M; Wilson, L J; Berka, R M

1990-03-01

272

Purification and Characterization of a Ginsenoside Rb1-Hydrolyzing ?-Glucosidase from Aspergillus niger KCCM 11239  

PubMed Central

Rb1-hydrolyzing ?-glucosidase from Aspergillus niger KCCM 11239 was studied to develop a bioconversion process for minor ginsenosides. The specific activity of the purified enzyme was 46.5 times greater than that of the crude enzyme. The molecular weight of the native enzyme was estimated to be approximately 123 kDa. The optimal pH of the purified enzyme was pH 4.0, and the enzyme proved highly stable over a pH range of 5.0–10.0. The optimal temperature was 70 °C, and the enzyme became unstable at temperatures above 60 °C. The enzyme was inhibited by Cu2+, Mg2+, Co2+, and acetic acid (10 mM). In the specificity tests, the enzyme was found to be active against ginsenoside Rb1, but showed very low levels of activity against Rb2, Rc, Rd, Re, and Rg1. The enzyme hydrolyzed the 20-C,?-(1?6)-glucoside of ginsenoside Rb1 to generate ginsenoside Rd and Rg3, and hydrolyzed 3-C,?-(1?2)-glucoside to generate F2. The properties of the enzyme indicate that it could be a useful tool in biotransformation applications in the ginseng industry, as well as in the development of novel drug compounds.

Chang, Kyung Hoon; Jo, Mi Na; Kim, Kee-Tae; Paik, Hyun-Dong

2012-01-01

273

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

PubMed

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?µm) 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?µg 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?µg of miconazole nitrate containing microcapsules revealed about 25% of growth inhibition while that of 150?µg 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

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

2011-12-16

274

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

SciTech Connect

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.)

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

1992-01-01

275

Preparation of a whole-cell biocatalyst of Aspergillus niger lipase and its practical properties.  

PubMed

Aspergillus niger lipase (ANL), a widely used hydrolase, was displayed for the first time on the surface of Saccharomyces cerevisiae using a-agglutinin as an anchor protein. Localization of ANL on the cell surface was confirmed by immunofluorescence microscopy. The displayed ANL was confirmed to be active toward tributyrin and p-nitrophenyl caprylate (pNPC). The hydrolytic activity toward pNPC reached 43.8 U/g of dry cell weight after induction by galactose for 72 h. The ANL-displaying cells were characterized for their use as whole-cell biocatalysts. The optimum temperature was 45 °C, and the pH was 7.0. The cells had good thermostability, retaining almost 80% of the full activity after incubation at 60 °C for 1 h, and >80% of the full activity at 50 °C for 6 h. The displayed lipase showed a preference for medium-chain fatty acid p-nitrophenyl esters. Therefore, the produced whole-cell catalyst is likely to have a wide range of applications. PMID:20828152

Liu, Wenshan; Jia, Bin; Zhao, Heyun; Xu, Li; Yan, Yunjun

2010-10-13

276

The effect of natamycin on the transcriptome of conidia of Aspergillus niger  

PubMed Central

The impact of natamycin on Aspergillus niger was analysed during the first 8 h of germination of conidia. Polarisation, germ tube formation, and mitosis were inhibited in the presence of 3 and 10 ?M of the anti-fungal compound, while at 10 ?M also isotropic growth was affected. Natamycin did not have an effect on the decrease of microviscosity during germination and the concomitant reduction in mannitol and trehalose levels. However, it did abolish the increase of intracellular levels of glycerol and glucose during the 8 h period of germination. Natamycin hardly affected the changes that occur in the RNA profile during the first 2 h of germination. During this time period, genes related to transcription, protein synthesis, energy and cell cycle and DNA processing were particularly up-regulated. Differential expression of 280 and 2586 genes was observed when 8 h old germlings were compared with conidia that had been exposed to 3 ?M and 10 ?M natamycin, respectively. For instance, genes involved in ergosterol biosynthesis were down-regulated. On the other hand, genes involved in endocytosis and the metabolism of compatible solutes, and genes encoding protective proteins were up-regulated in natamycin treated conidia.

van Leeuwen, M.R.; Krijgsheld, P.; Wyatt, T.T.; Golovina, E.A.; Menke, H.; Dekker, A.; Stark, J.; Stam, H.; Bleichrodt, R.; Wosten, H.A.B.; Dijksterhuis, J.

2013-01-01

277

Cellulase production by Aspergillus niger in biofilm, solid-state, and submerged fermentations.  

PubMed

Cellulase production by Aspergillus niger was compared in three different culture systems: biofilm, solid-state, and submerged fermentation. Biofilm and solid-state fermentations were carried out on perlite as inert support, and lactose was used as a carbon source in the three culture systems. In cryo-scanning electron microscopy, biofilm and solid-state cultures gave similar morphological patterns and confirmed that both spore first attachment and hyphal adhered growth are helped by the production of an adhesive extracellular matrix. Biofilm cultures produced higher cellulase activities than those in submerged and solid-state cultures (1,768, 1,165, and 1,174 U l(-1), respectively). Although biofilm cultures grew less than the other cultures, they produced significantly higher cellulase yields (370, 212, and 217 U g(-1) lactose, respectively) and volumetric productivities (24, 16, and 16 U l(-1) h(-1), respectively). Likewise, endoglucanase and xylanase activities were higher in biofilm cultures. Under the conditions tested, it seems that fungal attached growth on perlite may favor better enzyme production. Biofilms are efficient systems for cellulase production and may replace solid-state fermentation. Biofilm fermentation holds promise for further optimization and development. The results of this work reveal that fungal biofilms may be used for the commercial production of cellulase employing the technology developed for submerged fermentation at high cell densities. PMID:20354693

Gamarra, Norma N; Villena, Gretty K; Gutiérrez-Correa, Marcel

2010-03-31

278

Modeling and analysis of the dynamic behavior of the XlnR regulon in Aspergillus niger  

PubMed Central

Background In this paper the dynamics of the transcription-translation system for XlnR regulon in Aspergillus niger is modeled. The model is based on Hill regulation functions and uses ordinary differential equations. The network response to a trigger of D-xylose is considered and stability analysis is performed. The activating, repressive feedback, and the combined effect of the two feedbacks on the network behavior are analyzed. Results Simulation and systems analysis showed significant influence of activating and repressing feedback on metabolite expression profiles. The dynamics of the D-xylose input function has an important effect on the profiles of the individual metabolite concentrations. Variation of the time delay in the feedback loop has no significant effect on the pattern of the response. The stability and existence of oscillatory behavior depends on which proteins are involved in the feedback loop. Conclusions The dynamics in the regulation properties of the network are dictated mainly by the transcription and translation degradation rate parameters, and by the D-xylose consumption profile. This holds true with and without feedback in the network. Feedback was found to significantly influence the expression dynamics of genes and proteins. Feedback increases the metabolite abundance, changes the steady state values, alters the time trajectories and affects the response oscillatory behavior and stability conditions. The modeling approach provides insight into network behavioral dynamics particularly for small-sized networks. The analysis of the network dynamics has provided useful information for experimental design for future in vitro experimental work.

2011-01-01

279

Unfolding and refolding of Aspergillus niger PhyB phytase: role of disulfide bridges.  

PubMed

The role of disulfide bridges in the 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. The thiol reagent tris(2-carboxyethyl)phosphine (TCEP) reduces the refolding activity by 68%. The hydrodynamic radius (R(H)) of PhyB phytase decreased from 5.5 to 4.14 nm when the protein was subjected to 1.0 M GuCl concentration. The active homodimer, 183 kDa, was reduced to a 92 kDa monomer. The DLS data taken together with activity measurements could indicate whether refolding took place or not in PhyB phytase. The correlation between molecular mass and the state of unfolding and refolding is a very strong one in fungal phytase belonging to histidine acid phosphatase (HAP). Unlike PhyA phytase, for which sodium chloride treatment boosted the activity at 0.5 M salt concentration, PhyB phytase activity was severely inhibited under identical condition. Thus, PhyA and PhyB phytases are structurally very different, and their chemical environment in the active site and substrate-binding domain may be different to elicit such an opposite reaction to monovalent cations. PMID:18683944

Ullah, Abul H J; Sethumadhavan, Kandan; Mullaney, Edward J

2008-08-07

280

Exploring sequence characteristics related to high-level production of secreted proteins in Aspergillus niger.  

PubMed

Protein sequence features are explored in relation to the production of over-expressed extracellular proteins by fungi. Knowledge on features influencing protein production and secretion could be employed to improve enzyme production levels in industrial bioprocesses via protein engineering. A large set, over 600 homologous and nearly 2,000 heterologous fungal genes, were overexpressed in Aspergillus niger using a standardized expression cassette and scored for high versus no production. Subsequently, sequence-based machine learning techniques were applied for identifying relevant DNA and protein sequence features. The amino-acid composition of the protein sequence was found to be most predictive and interpretation revealed that, for both homologous and heterologous gene expression, the same features are important: tyrosine and asparagine composition was found to have a positive correlation with high-level production, whereas for unsuccessful production, contributions were found for methionine and lysine composition. The predictor is available online at http://bioinformatics.tudelft.nl/hipsec. Subsequent work aims at validating these findings by protein engineering as a method for increasing expression levels per gene copy. PMID:23049690

van den Berg, Bastiaan A; Reinders, Marcel J T; Hulsman, Marc; Wu, Liang; Pel, Herman J; Roubos, Johannes A; de Ridder, Dick

2012-10-01

281

Heterologous expression and biochemical characterization of alpha-glucosidase from Aspergillus niger by Pichia pastroris.  

PubMed

The aglu of Aspergillus niger encodes the pro-protein of alpha-glucosidase, and the mature form of wild-type enzyme is a heterosubunit protein. In the present study, the cDNA of alpha-glucosidase was cloned and expressed in Pichia pastoris strain KM71. The activity of recombinant enzyme in a 3 L fermentor reached 2.07 U/mL after 96 h of induction. The recombinant alpha-glucosidase was able to produce oligoisomaltose. The molecular weight of the recombinant enzyme was estimated to be about 145 kDa by SDS-PAGE, and it reduced to 106 kDa after deglycosylation. The enzymatic activity of recombinant alpha-glucosidase was not significantly affected by a range of metal ions. The optimum temperature of the enzyme was 60 degrees C, and it was stable below 50 degrees C. The enzyme was active over the range of pH 3.0-7.0 with maximal activity at pH 4.5. Using pNPG as substrate, the K(m) and V(max) values were 0.446 mM and 43.48 U/mg, respectively. These studies provided the basis for the application of recombinant alpha-glucosidase in the industry of functional oligosaccharides. PMID:20369871

Chen, Dong-Li; Tong, Xing; Chen, Shang-Wei; Chen, Sheng; Wu, Dan; Fang, Shu-Guang; Wu, Jing; Chen, Jian

2010-04-28

282

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

PubMed Central

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.

Medina, Angel; Mateo, Rufino; Lopez-Ocana, Laura; Valle-Algarra, Francisco Manuel; Jimenez, Misericordia

2005-01-01

283

Studies of In Vitro Activities of Voriconazole and Itraconazole against Aspergillus Hyphae Using Viability Staining  

Microsoft Academic Search

The minimal fungicidal concentrations (MFCs) of voriconazole and itraconazole for five clinical isolates each of Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, and Aspergillus niger were determined by a broth macrodilution method. Conidial suspensions as inocula were compared to hyphae as inocula since the invasive form of aspergillosis is manifested by the appearance of hyphal structures. In addition, cell viability staining

CORNELIA LASS-FLORL; MARKUS NAGL; CORNELIA SPETH; HANNO ULMER; MANFRED P. DIERICH; REINHARD WURZNER

2001-01-01

284

Effect of water activity, temperature and incubation time on growth and ochratoxin A production by Aspergillus niger and Aspergillus carbonarius on maize kernels.  

PubMed

The aim of this study was to determine the effects of water activity (a(w)) (0.92-0.98), temperature (5-45 °C) and incubation time (5-60 days) on growth and ochratoxin A (OTA) production by Aspergillus niger and Aspergillus carbonarius on maize kernels using a simple method. Colony diameters of both strains at 0.92 a(w) were significantly lower than those at 0.96 and 0.98 a(w) levels. The optimum growth temperature range for A. niger was 25-40 °C and for A. carbonarius 20-35 °C. A. niger produced OTA from 15 to 40 °C, and the highest OTA level was recorded at 15 °C. The concentration of OTA produced at 0.92 a(w) was significantly lower than those at 0.96 and 0.98 a(w). A. carbonarius produced OTA from 15 to 35 °C and the maximum concentration was achieved at 15 °C, although not differing statistically from the concentration detected at 20 °C. At 0.98 a(w) the OTA concentration was significantly higher than at 0.96 and 0.92 a(w). Our results show that maize supports both growth and OTA production by A. niger and A. carbonarius. The studied strains were able to produce OTA in maize kernels from the fifth day of incubation over a wide range of temperatures and water availabilities. Although the limit of quantification of our method was higher than that required for the analysis of OTA in food commodities, it has proved to be a useful and rapid way to detect OTA production by fungi inoculated onto natural substrates, in a similar way as for pure culture. Both species could be a source of OTA in this cereal in temperate and tropical zones of the world. PMID:21444120

Alborch, L; Bragulat, M R; Abarca, M L; Cabañes, F J

2011-03-09

285

Two Cellobiohydrolase-Encoding Genes from Aspergillus niger Require d-Xylose and the Xylanolytic Transcriptional Activator XlnR for Their Expression  

PubMed Central

Two cellobiohydrolase-encoding genes, cbhA and cbhB, have been isolated from the filamentous fungus Aspergillus niger. The deduced amino acid sequence shows that CbhB has a modular structure consisting of a fungus-type cellulose-binding domain (CBD) and a catalytic domain separated by a Pro/Ser/Thr-rich linker peptide. CbhA consists only of a catalytic domain and lacks a CBD and linker peptide. Both proteins are homologous to fungal cellobiohydrolases in family 7 of the glycosyl hydrolases. Northern blot analysis showed that the transcription of the cbhA and cbhB genes is induced by d-xylose but not by sophorose and, in addition, requires the xylanolytic transcriptional activator XlnR.

Gielkens, Marco M. C.; Dekkers, Ester; Visser, Jaap; de Graaff, Leo H.

1999-01-01

286

Improvement of Foreign-Protein Production in Aspergillus niger var. awamori by Constitutive Induction of the Unfolded-Protein Response  

PubMed Central

Unfolded-protein response (UPR) denotes the upregulation of endoplasmic reticulum (ER)-resident chaperone and foldase genes and numerous other genes involved in secretory functions during the accumulation of unfolded proteins into the ER. Overexpression of individual foldases and chaperones has been used in attempts to improve protein production in different production systems. We describe here a novel strategy to improve foreign-protein production. We show that the constitutive induction of the UPR pathway in Aspergillus niger var. awamori can be achieved by expressing the activated form of the transcription factor hacA. This induction enhances the production of Trametes versicolor laccase by up to sevenfold and of bovine preprochymosin by up to 2.8-fold in this biotechnically important fungus. The regulatory range of UPR was studied by analyzing the mRNA levels of novel A. niger var. awamori genes involved in different secretory functions. This revealed both similarities and differences to corresponding studies in Saccharomyces cerevisiae.

Valkonen, Mari; Ward, Michael; Wang, Huaming; Penttila, Merja; Saloheimo, Markku

2003-01-01

287

Activity stabilization of Aspergillus niger and Escherichia coli phytases immobilized on allophanic synthetic compounds and montmorillonite nanoclays.  

PubMed

The aim of this work was to study the stabilization of the activity of two commercial microbial phytases (Aspergillus niger and Escherichia coli) after immobilization on nanoclays and to establish optimal conditions for their immobilization. Synthetic allophane, synthetic iron-coated allophanes and natural montmorillonite were chosen as solid supports for phytase immobilization. Phytase immobilization patterns at different pH values were strongly dependent on both enzyme and support characteristics. After immobilization, the residual activity of both phytases was higher under acidic conditions. Immobilization of phytases increased their thermal stability and improved resistance to proteolysis, particularly on iron-coated allophane (6% iron oxide), which showed activation energy (E(a)) and activation enthalpy (?H(#)) similar to free enzymes. Montmorillonite as well as allophanic synthetic compounds resulted in a good support for immobilization of E. coli phytase, but caused a severe reduction of A. niger phytase activity. PMID:21856150

Menezes-Blackburn, Daniel; Jorquera, Milko; Gianfreda, Liliana; Rao, Maria; Greiner, Ralf; Garrido, Elizabeth; de la Luz Mora, María

2011-07-22

288

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

PubMed

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

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

2005-06-24

289

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

PubMed Central

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.

Martens-Uzunova, Elena S.; Zandleven, Joris S.; Benen, Jaques A. E.; Awad, Hanem; Kools, Harrie J.; Beldman, Gerrit; Voragen, Alphons G. J.; Van Den Berg, Johan A.; Schaap, Peter J.

2006-01-01

290

Biotransformation of (1-phenyl)ethyl hydroperoxide with Aspergillus niger: a model study on enzyme selectivity and on the induction of peroxidase activity  

Microsoft Academic Search

The biocatalytic enantioselective reduction of (1-phenyl)ethyl hydroperoxide (1) by the fungus Aspergillus niger to the corresponding alcohol 2 involves a multi-enzyme biotransformation of the hydroperoxide 1, as revealed by the change in the enantioselectivity as a function of incubation times. This unusual behavior is not exhibited by other fungi and seems to be restricted to A. niger. Furthermore, the peroxidase

Waldemar Adam; Zoltan Lukacs; Chantu R Saha-Möller; Peter Schreier

1999-01-01

291

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

PubMed Central

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 P21 symmetry with eight molecules per asymmetric unit and the latter has P41212 or P43212 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.

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

2008-01-01

292

Biotransformation of polydatin to resveratrol in Polygonum cuspidatum roots by highly immobilized edible Aspergillus niger and Yeast.  

PubMed

A new biotransformation method of producing resveratrol with co-immobilized edible Aspergillus niger and Yeast (AY) was investigated. The biotransformation conditions were optimized for the resveratrol production under 30 °C, pH 6.5, 2 days, liquid-solid ratio 12:1 (mL/g), the yield of resveratrol reached 33.45 mg/g, which increased 11-fold to that of untreated one. The conversion rate of polydatin reached 96.7%. The residual activity of immobilized microorganism was 83.2% after used for 15 runs. The developed method could be an effectively alternative biotransformation method for producing resveratrol from the plants. PMID:23566471

Jin, Shuang; Luo, Meng; Wang, Wei; Zhao, Chun-jian; Gu, Cheng-bo; Li, Chun-ying; Zu, Yuan-gang; Fu, Yu-jie; Guan, Yue

2013-03-15

293

Continuous hydrolysis of 4-cyanopyridine by nitrilases from Fusarium solani O1 and Aspergillus niger K10  

Microsoft Academic Search

The operational stabilities of nitrilases from Aspergillus niger K10 and Fusarium solani O1 were examined with 4-cyanopyridine as the substrate in continuous-stirred membrane reactors (CSMRs). The former enzyme\\u000a was fairly stable at 30 °C with a deactivation constant (k\\u000a d) and enzyme half-life of 0.014 h?1 and 50 h, respectively, but the latter exhibited an even higher stability characterized by k\\u000a d?=?0.008 h?1 and

Anna Malandra; Maria Cantarella; Ond?ej Kaplan; Vojt?ch Vejvoda; Bronislava Uhnáková; Barbora Št?pánková; David Kubá?; Ludmila Martínková

2009-01-01

294

Purification and characterisation of two exo-polygalacturonases from Aspergillus niger able to degrade xylogalacturonan and acetylated homogalacturonan  

Microsoft Academic Search

Two exo-polygalacturonases (EC 3.2.1.67) were purified from a commercial Aspergillus niger enzyme preparation by ammonium sulfate precipitation, preparative electrofocusing, anion-exchange and size-exclusion chromatographies. The enzymes had molar masses of 82 kDa (exo-PG1) and 56 kDa (exo-PG2). Exo-PG1 was stable over wider pH and temperature ranges than exo-PG2. Addition of 0.01 mM HgCl2 increased the exo-PG2 activity 3.4 times but did

T Sakamoto; E Bonnin; B Quemener; J.-F Thibault

2002-01-01

295

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

SciTech Connect

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.

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

1981-01-01

296

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

PubMed Central

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.

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

2013-01-01

297

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

PubMed

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

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

2012-09-20

298

Synthesis of highly water-soluble feruloyl diglycerols by esterification of an Aspergillus niger feruloyl esterase.  

PubMed

Ferulic acid (FA) is a component of plant cell walls that has applications in food, cosmetic, and health products, but its applications are limited by its high insolubility. We synthesized water-soluble FA derivatives by esterification of FA with diglycerol (DG) using feruloyl esterase purified from a commercial enzyme preparation produced by Aspergillus niger. The major reaction product, FA-DG1, was determined to be ?-feruloyl-?,?'-DG by NMR and electrospray ionization mass spectrometry analyses. FA-DG1 is a sticky liquid whose water solubility (>980 mg/ml) is dramatically higher than that of FA (0.69 mg/ml). Suitable conditions for esterification of FA with DG were 100 mg of FA in the presence of 1 g of DG and 0.1 ml of 1 M phosphate buffer (pH 6.0) at 50 °C under reduced pressure. Under these conditions, 168 mg of feruloyl DGs (FA-DG1, 2, and 3) was obtained, corresponding to a 95 % conversion rate of FA. We also developed a batch method which resulted in synthesis of 729 mg of feruloyl DGs and 168 mg of diferuloyl DGs from 600 mg of FA and 1 g of DG (corresponding to conversion of 69 % of the FA to feruloyl DGs and 21 % of the FA to diferuloyl DGs). As an anti-oxidant, feruloyl DGs were essentially equal to FA and butyl hydroxytoluene in scavenging 1,1-diphenyl-2-picrylhydrazyl radicals. In contrast, the scavenging abilities of diferuloyl DGs were twice those of feruloyl DGs. PMID:22526804

Kikugawa, Masaki; Tsuchiyama, Moriyasu; Kai, Kenji; Sakamoto, Tatsuji

2012-04-15

299

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

PubMed Central

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.

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

2011-01-01

300

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

PubMed

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

Kant, Shashi; Vohra, Anuja; Gupta, Reena

2012-10-13

301

Identification of a Transcription Factor Controlling pH-Dependent Organic Acid Response in Aspergillus niger  

PubMed Central

Acid formation in Aspergillus niger is known to be subjected to tight regulation, and the acid production profiles are fine-tuned to respond to the ambient pH. Based on transcriptome data, putative trans-acting pH responding transcription factors were listed and through knock out studies, mutants exhibiting an oxalate overproducing phenotype were identified. The yield of oxalate was increased up to 158% compared to the wild type and the corresponding transcription factor was therefore entitled Oxalic Acid repression Factor, OafA. Detailed physiological characterization of one of the ?oafA mutants, compared to the wild type, showed that both strains produced substantial amounts of gluconic acid, but the mutant strain was more efficient in re-uptake of gluconic acid and converting it to oxalic acid, particularly at high pH (pH 5.0). Transcriptional profiles showed that 241 genes were differentially expressed due to the deletion of oafA and this supported the argument of OafA being a trans-acting transcription factor. Furthermore, expression of two phosphoketolases was down-regulated in the ?oafA mutant, one of which has not previously been described in fungi. It was argued that the observed oxalate overproducing phenotype was a consequence of the efficient re-uptake of gluconic acid and thereby a higher flux through glycolysis. This results in a lower flux through the pentose phosphate pathway, demonstrated by the down-regulation of the phosphoketolases. Finally, the physiological data, in terms of the specific oxygen consumption, indicated a connection between the oxidative phosphorylation and oxalate production and this was further substantiated through transcription analysis.

Poulsen, Lars; Andersen, Mikael R?rdam; Lantz, Anna Eliasson; Thykaer, Jette

2012-01-01

302

Biochemical and biophysical response to calcium chloride stress in Aspergillus niger and its role in malachite green degradation.  

PubMed

Filamentous fungi show great promise in remediation of environmental contaminants such as industrial dyes. In the current study, Aspergillus niger (Genbank ID: JF437542) decolorized 82 % of the test dye malachite green (MG; 50 mg/l) during cultivation for 24 h. The organism decolorized only 6 % of the MG at higher concentration (250 mg MG/l) during the same time period and growth was inhibited at this higher MG concentration. Exposing A. niger to different types of stress resulted in variable impacts on ability to decolorize MG. CaCl2 had the largest positive impact on decolorization. A. niger cultures treated with CaCl2 (1 M) decolorized 46 % of the MG (250 mg/l) in 1 h compared to 6 % in untreated control cultures. CaCl2 also increased catalase production in A. niger which strongly supported a direct relationship between stress response and decolorizing ability. Spectrophotometric measurement confirmed MG decolorization while Fourier transform infrared spectroscopy suggested that biodegradation of MG occurred. Cultures treated with CaCl2 accumulated fewer toxic MG by-products than untreated cultures. CaCl2-induced stress increased the permeability and conductivity of the fungal cell membrane. An observed increase in medium [H(+)] also suggested a change in Ca(2+)/H(+) exchange capacity in the fungal cell. Calcium ions had a pronounced effect on membrane properties and this may have had an important impact on signal transduction. We conclude that A. niger decolorizes MG and that CaCl2 enhances this process; the CaCl2 effect appears to be associated with stress response. PMID:23076635

Gomaa, Ola M; Selim, Nabila S; Linz, John E

2013-04-01

303

Expression in Escherichia coli, refolding and crystallization of Aspergillus niger feruloyl esterase A using a serial factorial approach.  

PubMed

Hydrolysis of plant biomass is achieved by the combined action of enzymes secreted by microorganisms and directed against the backbone and the side chains of plant cell wall polysaccharides. Among side chains degrading enzymes, the feruloyl esterase A (FAEA) specifically removes feruloyl residues. Thus, FAEA has potential applications in a wide range of industrial processes such as paper bleaching or bio-ethanol production. To gain insight into FAEA hydrolysis activity, we solved its crystal structure. In this paper, we report how the use of four consecutive factorial approaches (two incomplete factorials, one sparse matrix, and one full factorial) allowed expressing in Escherichia coli, refolding and then crystallizing Aspergillus niger FAEA in 6 weeks. Culture conditions providing the highest expression level were determined using an incomplete factorial approach made of 12 combinations of four E. coli strains, three culture media and three temperatures (full factorial: 36 combinations). Aspergillus niger FAEA was expressed in the form of inclusion bodies. These were dissolved using a chaotropic agent, and the protein was purified by affinity chromatography on Ni column under denaturing conditions. A suitable buffer for refolding the protein eluted from the Ni column was found using a second incomplete factorial approach made of 96 buffers (full factorial: 3840 combinations). After refolding, the enzyme was further purified by gel filtration, and then crystallized following a standard protocol: initial crystallization conditions were found using commercial crystallization screens based on a sparse matrix. Crystals were then optimized using a full factorial screen. PMID:17533138

Benoit, Isabelle; Coutard, Bruno; Oubelaid, Rachid; Asther, Marcel; Bignon, Christophe

2007-04-10

304

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  

Microsoft Academic Search

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, amphotericin 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,

M. A Pfaller; F Marco; S. A Messer; R. N Jones

1998-01-01

305

Catalytic and thermodynamic properties of a tannase produced by Aspergillus niger GH1 grown on polyurethane foam.  

PubMed

Tannase is an inducible enzyme with important applications in the food and pharmaceutical industries. This enzyme was produced by the fungus Aspergillus niger GH1 under solid-state fermentation using polyurethane foam as solid support and tannic acid as sole carbon source and tannase inducer. Physicochemical properties of A. niger tannase were characterized, and the kinetic and thermodynamics parameters on methyl gallate hydrolysis were evaluated. The enzyme was stable in a pH range of 2-8 and a functional temperature range of 25-65 °C. The highest k(cat) value was 2,611.10 s(-1) at 65 °C. Tannase had more affinity for methyl gallate at 45 °C with a K(M) value of 1.82 mM and an efficiency of hydrolysis (k(cat)/K(M)) of 330.01 s(-1) mM(-1). The lowest E(a) value was found to be 21.38 kJ/mol at 4.4 mM of methyl gallate. The lowest free energy of Gibbs (?G) and enthalpy (?H) were found to be 64.86 and 18.56 kJ/mol, respectively. Entropy (?S) was -0.22 kJ/mol K. Results suggest that the A. niger GH1 tannase is an attractive enzyme for industrial applications due its catalytic and thermodynamical properties. PMID:21837378

Ramos, Erika L; Mata-Gómez, Marco A; Rodríguez-Durán, Luis V; Belmares, Ruth E; Rodríguez-Herrera, Raúl; Aguilar, Cristóbal Noe

2011-08-12

306

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

PubMed

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

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

2010-08-01

307

The antifungal efficacy of nano-metals supported TiO2 and ozone on the resistant Aspergillus niger spore.  

PubMed

Recently, antimicrobial efficacy of nano-metals has been extensively investigated. However, most of the related studies focused on the bactericidal effectiveness. Molds, especially their spores, are more resistant than bacteria, and can build a high concentration in houses due to dampness. Therefore, a comprehensive evaluation of the antifungal effectiveness of nano-metals is necessary. In this study, the nano-metals (Ag, Cu and Ni) supported catalysts were successfully prepared by the incipient wetness impregnation method, while the titanium dioxide (Degussa (Evonik) P25) nanoparticle was served as the support. The antifungal experiments of Aspergillus niger spores were conducted on two surfaces (quartz and putty) in the darkness with and without ozone exposure, respectively. The critical Ag concentration to inhibit the germination and growth of A. niger spores of 5wt% nano Ag catalyst was 65mg/mL, lower than several cases in previous studies. The inactivation rate constants (k) of A. niger spores on nano-metals supported catalysts in the presence of ozone (k=0.475-0.966h(-1)) were much higher than those in the absence of ozone (k=0.001-0.268h(-1)). However, on the surface of TiO2 particles, no antifungal effect was observed until 6-h exposure to ozone. Consequently, ozone has a synergetic effect on nano-metals antifungal efficacy. PMID:23921178

Yu, Kuo-Pin; Huang, Yi-Ting; Yang, Shang-Chun

2013-07-22

308

Deletion of flbA Results in Increased Secretome Complexity and Reduced Secretion Heterogeneity in Colonies of Aspergillus niger.  

PubMed

Aspergillus niger is a cell factory for the production of enzymes. This fungus secretes proteins in the central part and at the periphery of the colony. The sporulating zone of the colony overlapped with the nonsecreting subperipheral zone, indicating that sporulation inhibits protein secretion. Indeed, strain ?flbA that is affected early in the sporulation program secreted proteins throughout the colony. In contrast, the ?brlA strain that initiates but not completes sporulation did not show altered spatial secretion. The secretome of 5 concentric zones of xylose-grown ?flbA colonies was assessed by quantitative proteomics. In total 138 proteins with a signal sequence for secretion were identified in the medium of ?flbA colonies. Of these, 18 proteins had never been reported to be part of the secretome of A. niger, while 101 proteins had previously not been identified in the culture medium of xylose-grown wild type colonies. Taken together, inactivation of flbA results in spatial changes in secretion and in a more complex secretome. The latter may be explained by the fact that strain ?flbA has a thinner cell wall compared to the wild type, enabling efficient release of proteins. These results are of interest to improve A. niger as a cell factory. PMID:23461488

Krijgsheld, Pauline; Nitsche, Benjamin M; Post, Harm; Levin, Ana M; Müller, Wally H; Heck, Albert J R; Ram, Arthur F J; Altelaar, A F Maarten; Wösten, Han A B

2013-03-22

309

Stability of Glucose Oxidase Activity of Aspergillus niger Spores Produced by Solid-State Fermentation and Their Role as Biocatalysts in Bioconversion Reaction  

Microsoft Academic Search

Summary The aim of this work is to demonstrate the role of conidial spores as a reservoir of glucose oxidase and their stability as a biocatalyst in the bioconversion reaction for the production of gluconic acid. Solid-state fermentation (SSF) was carried out in fixed-bed column bioreactor for the production of Aspergillus niger spores. Growth parameters, sporulation and kinetics of gluconic

Sumitra Ramachandran; Pierre Fontanille; Ashok Pandey; Christian Larroche

310

The effect of various food parameters on the activity and stability of catalase from Aspergillus niger and catalase from bovine liver  

Microsoft Academic Search

The effects of a number of food relevant parameters on catalase activity and stability were studied. The direct responses of different combinations of the parameters ethanol, pH and ionic strength on bovine liver catalase and Aspergillus niger catalase activity were investigated in a full factorial 24 statistically designed experiment. Statistically significant effects (p = 0.001) on both types of catalases

Anne S. Meyer; Lærke H. Pedersen; Anette Isaksen

1997-01-01

311

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...

312

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 ...

313

Screening of natural substrates and optimization of operating variables on the production of pectinase by submerged fermentation using Aspergillus niger MTCC 281  

Microsoft Academic Search

Pectinases are a group of hydrolytic enzymes that play an important role in food processing industry and alcoholic beverage industry. The present work aims at studying different natural substrates such as wheat flour and corn flour in comparison with synthetic pectin for the production of pectinase using Aspergillus niger (MTCC: 281). The work involves optimizing various parameters like substrate concentration,

M. Palaniyappan; V. Vijayagopal; Renuka Viswanathan; T. Viruthagiri

2009-01-01

314

Production of ?-Glucosidase from a Newly Isolated Aspergillus Species Using Response Surface Methodology  

PubMed Central

A newly isolated fungus Aspergillus niger SOI017 was shown to be a good producer of ?-glucosidase from all isolated fungal strains. Fermentation condition (pH, cellobiose concentration, yeast extract concentration, and ammonium sulfate concentration) was optimized for producing the enzyme in shake flask cultures. Response surface methodology was used to investigate the effects of 4 fermentation parameters (yeast extract concentration, cellobiose concentration, ammonium sulfate concentration, and pH) on ?-glucosidase enzyme production. Production of ?-glucosidase was most sensitive to the culture medium, especially the nitrogen source yeast extract. The optimized medium for producing maximum ?-glucosidase specific activity consisted of 0.275% yeast extract, 1.125% cellobiose, and 2.6% ammonium sulfate at a pH value of 3.

Vaithanomsat, Pilanee; Songpim, Molnapat; Malapant, Taweesiri; Kosugi, Akihiko; Thanapase, Warunee; Mori, Yutaka

2011-01-01

315

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

PubMed Central

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.

2010-01-01

316

Optimization of tannase production by Aspergillus niger in solid-state packed-bed bioreactor.  

PubMed

Tannin acyl hydrolase, also known as tannase, is an enzyme with important applications in the food, feed, pharmaceutical, and chemical industries. However, despite a growing interest in the catalytic properties of tannase, its practical use is very limited owing to high production costs. Several studies have already demonstrated the advantages of solid-state fermentation (SSF) for the production of fungal tannase, yet the optimal conditions for enzyme production strongly depend on the microbial strain utilized. Therefore, the aim of this study was to improve the tannase production by a locally isolated A. niger strain in an SSF system. The SSF was carried out in packed-bed bioreactors using polyurethane foam as an inert support impregnated with defined culture media. The process parameters influencing the enzyme production were identified using a Plackett–Burman design, where the substrate concentration, initial pH, and incubation temperature were determined as the most significant. These parameters were then further optimized using a Box-Behnken design. The maximum tannase production was obtained with a high tannic acid concentration (50 g/l), relatively low incubation temperature (30°C), and unique low initial pH (4.0). The statistical strategy aided in increasing the enzyme activity nearly 1.97-fold, from 4,030 to 7,955 U/l. Consequently, these findings can lead to the development of a fermentation system that is able to produce large amounts of tannase in economical, compact, and scalable reactors. PMID:21952373

Rodríguez-Durán, Luis V; Contreras-Esquivel, Juan C; Rodríguez, Raúl; Prado-Barragán, L Arely; Aguilar, Cristóbal N

2011-09-01

317

[Antifungal susceptibilities of Aspergillus spp. strains isolated from invasive aspergillosis cases].  

PubMed

Aspergillus species found abundantly in the outer environment and hospital setting may lead to serious morbidity and mortality particularly in patients with suppressed immunity. This retrospective study was aimed to investigate the antifungal susceptibilities of Aspergillus spp. isolated from aspergillosis cases being hospitalized. Aspergillus spp. isolated from samples of the patients with suspected fungal infections between January of 2002 and October of 2007, were investigated. A total of 678 samples (420 lower respiratory tract, 202 sterile body fluids, and 56 biopsy/tissue specimens) from 569 patients were included in the study. The samples were incubated in 25 degrees C and 35 degrees C on brain-heart-infusion agar supplemented with blood and on Sabouraud dextrose agar. Gram and Giemsa stained samples were also examined by microscopy. Mold type of fungi were identified by conventional techniques. "Invasive aspergillosis" was described according to criteria of Invasive Fungal Infections Cooperative Group of the European Organization for Research and Treatment of Cancer. A. fumigatus (n = 8), A. flavus (n = 2) and A. niger (n = 2) were isolated from 12 patients' samples (2.1%), 9 of them were lower respiratory tract and one of each was ascid, brain biopsy and pleural fluid specimens. All of those patients have had an underlying diseases such as malignancy. The susceptibility of the isolates to caspofungin, voriconazole, itraconazole and amphotericin B was tested by broth microdilution susceptibility testing and to posaconazole by E-test (AB Biodisk, Sweden). The lowest minimum inhibitory concentration (MIC) (< or = 0.125 microg/ml) values were detected for caspofungin and posaconazole for Aspergillus spp., however, the highest MIC values were detected for amphotericin B (> 1 microg/ml). MIC values of the all strains except one, were detected as < or = 0.5 microg/ml for voriconazole and itraconazole. In one A. niger strain itraconazole MIC value was 2 microg/ml. Since the number of other species was low, MIC50 value was determined only for A. fumigatus strains and it was found that the highest MIC50 value was for amphotericin B (2 microg/ml) and the lowest MIC50 values were for posaconazole (0.064 microg/ml), caspofungin (0.064 microg/ml), itraconazol (0.25 microg/ml) and voriconazol (0.25 microg/ml). Since caspofungin and posaconazole revealed the lowest MIC values, they should be taken into consideration in choice of therapy of aspergillosis cases in our hospital. PMID:20549962

Gürcan, Saban; Tikve?li, Melek; Eryildiz, Canan; Evci, Canan; Ener, Beyza

2010-04-01

318

Partition in aqueous two-phase system: its application in downstream processing of tannase from Aspergillus niger.  

PubMed

Tannase from Aspergillus niger was partitioned in aqueous two-phase systems composed by polyethyleneglycol of molar mass 400, 600 and 1000 and potassium phosphate. Tannase was found to be partitioned toward the salt-rich phase in all systems, with partition coefficients lower than 0.5. Partition coefficients values and low entropic and enthalpic changes associated with tannase partition suggest that the entropic effect may be the driving force of the concentration of the enzyme in the bottom phase due to the high molar mass of the enzyme. The process was significantly influenced by the top phase/bottom phase volume ratio. When the fungal culture broth was partitioned in these systems, a good performance was found, since the enzyme recovery in the bottom phase of the system composed by polyethyleneglycol 1000 was around 96% with a 7.0-fold increase in purity. PMID:23010046

Rodríguez-Durán, Luis V; Spelzini, Darío; Boeris, Valeria; Aguilar, Cristóbal N; Picó, Guillermo A

2012-07-25

319

Influence of agitation speed on tannase production and morphology of Aspergillus niger FETL FT3 in submerged fermentation.  

PubMed

Agitation speed was found to influence the tannase production and fungal growth of Aspergillus niger FETL FT3. The optimal agitation speed was at 200 rpm which produced 1.41 U/ml tannase and 3.75 g/l of fungal growth. Lower or higher agitation speeds than 200 rpm produced lower enzyme production and fungal growth. Based on the SEM and TEM micrograph observation, there was a significant correlation between agitation speed and the morphology of the fungal mycelia. The results revealed an increase of the enzyme production with the change of the fungal growth morphology from filamentous to pelleted growth forms. However, the exposure to higher shear stress with an increasing agitation speed of the shaker also resulted in lower biomass yields as well as enzyme production. PMID:21947762

Darah, I; Sumathi, G; Jain, K; Lim, S H

2011-09-27

320

[Influence of the interaction of temperature and water activity on the production of ochratoxin A and the growth of Aspergillus niger, Aspergillus carbonarius and Aspergillus ochraceus on coffee-based culture medium].  

PubMed

In the present study, the effect of temperature and water activity on fungal growth and ochratoxin production on coffee-based medium was assessed. Optimal growth of three Aspergillus strains was observed in the same ecological conditions, namely 30 degrees C and 0.99 water activity. Maximal daily growth is 11.2, 6.92, and 7.22 mm/day for Aspergillus niger, Aspergillus carbonarius, and Aspergillus ochraceus, respectively. However, ecological conditions for optimal ochratoxin production vary according to the toxinogenic strain, with water activity as a limiting factor. Such an ochratoxin A production is inhibited at 42 degrees C and 0.75 water activity. Correspondence between laboratory tested water activity and that measured on a sun-dried ripe cherry batch shows that the first 5 days of drying are critical for fungal growth and ochratoxin A production. Accordingly, artificial drying of cherries at temperatures above 42 degrees C will impede not only fungal growth but also contamination with ochratoxin A. PMID:17898840

Kouadio, Ahou Irène; Lebrihi, Ahmed; Agbo, Georges N' Zi; Mathieu, Florence; Pfohl-Leszkowiz, Annie; Dosso, Mireille Bretin

2007-07-01

321

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

PubMed Central

Aspergillus niger NCIM 563 produced two different extracellular phytases (Phy I and Phy II) under submerged fermentation conditions at 30°C 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 SDS–PAGE and gel filtration were 66, 264, 150 and 148 kDa 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 (1.5–9.0) while Phy II showed a pH optimum of 5.0 with stability in the range of pH 3.5–9.0. 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+ (1 mM) 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 0.145 mM while Vmax was 5,018 and 1,671 ?mol min?1 mg?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.

Soni, S. K.; Magdum, A.

2010-01-01

322

The solubilization of potassium-bearing rock powder by Aspergillus niger in small-scale batch fermentations.  

PubMed

The fungus Aspergillus niger was cultivated in culture medium with an alkaline ultramafic rock powder to evaluate the solubilization of potassium for biofertilizer production. The assays were carried out with 2 strains (CCT4355 and CCT911) in small-scale batch fermentations using 125, 500, 1000, and 2000 mL Erlenmeyer flasks, with a nominal volume of 40%, and rock powder at 0.4%, shaken at 160 r/min, incubated at 30 degrees C, and sampled every 7 days for 35 days. The amount of soluble K(+), the pH of the culture medium, and the acidity were determined. Both strains solubilized K(+) from the rock powder to the same extent (approximately 62%-70% after 35 days) in the 125 mL flasks; however, the percent solubilization decreased at higher volumetric scales. The results also indicated a difference in strain sensitivity to the increase in volumetric scales in batch fermentation. When filter-sterilized air was injected into the medium, the K(+) percent solubilization obtained after 4 days of cultivation was similar to that obtained after a 28 day period. The acid production by the fungus may be a mechanism of rock solubilization, in spite of the elevation in pH values probably caused by the increasing hydrolysis of the silicates. Both strains of A. niger are recommended for solubilizing potassium from ultramafic rocks, but it is necessary to optimize the oxygen transfer, which seemed to affect the rock solubilization at higher volumetric scales. PMID:20651859

Lopes-Assad, Maria L; Avansini, Simoni H; Rosa, Márcia M; de Carvalho, José R P; Ceccato-Antonini, Sandra R

2010-07-01

323

Effects of Cymbopogon citratus L. essential oil on the growth, lipid content and morphogenesis of Aspergillus niger ML2-strain.  

PubMed

The mycelial growth of Aspergillus niger van Tieghem was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 70% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. niger hyphae after treatment with C. citratus essential oil. The hyphal diameter and hyphal wall appeared markedly thinner. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca+2, K+ and Mg+2 leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated fatty acids decreased and unsaturated fatty acids increased. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegrading and storage contaminating fungi and in fruit juice preservation. PMID:17139611

Helal, G A; Sarhan, M M; Abu Shahla, A N K; Abou El-Khair, E K

2006-01-01

324

Effects of Cymbopogon nardus (L.) W. Watson essential oil on the growth and morphogenesis of Aspergillus niger.  

PubMed

The growth inhibitory effect of Cymbopogon nardus (L.) W. Watson var. nurdus essential oil on Aspergillus niger (Van Tieghem) mycelium was determined on agar medium. The mycelium growth was completely inhibited at 800 mg/L. This concentration was found to be lethal under the test conditions. Essential oil at 400 mg/L caused growth inhibition of 80% after 4 days of incubation, and a delay in conidiation of 4 days compared with the control. Microscopic observations were carried out to determine the ultrastructural modifications of A. niger hyphae after treatment with C. nardus essential oil. The main change observed by transmission electron microscopy concerned the hyphal diameter and the hyphal wall, which appeared markedly thinner. These modifications in cytological structure might be caused by the interference of the essential oil with the enzymes responsible for wall synthesis which disturb normal growth. Moreover, the essential oil caused plasma membrane disruption and mitochondrial structure disorganization. The findings thus indicate the possibility of exploiting Cymbopogon nardus essential oil as an effective inhibitor of biodegrading and storage-contaminating fungi. PMID:15049444

de Billerbeck, V G; Roques, C G; Bessière, J M; Fonvieille, J L; Dargent, R

2001-01-01

325

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

NASA Astrophysics Data System (ADS)

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.

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

326

Presence and regulation of the alpha-ketoglutarate dehydrogenase multienzyme complex in the filamentous fungus Aspergillus niger.  

PubMed Central

alpha-Ketoglutarate dehydrogenase has been demonstrated for the first time in cell extracts from the filamentous fungus Aspergillus niger. A minimum protein concentration of 5 mg/ml is necessary for detecting enzyme activity, but a maximum of ca. 0.060 mumol/min per mg of protein is observed only when the protein concentration is above 9 mg/ml. alpha-Ketoglutarate can partly stabilize the enzyme against dilution in the assay system. Neither bovine serum albumin nor a variety of substrates or effectors of the enzyme could stabilize the enzyme against inactivation by dilution. A kinetic analysis of the enzyme revealed Michaelis-Menten kinetics with respect to alpha-ketoglutarate, coenzyme A, and NAD. Thiamine PPi was required for maximal activity. NADH, oxaloacetate, succinate, and cis-aconitate were found to inhibit the enzyme; AMP was without effect. Monovalent cations including NH4+ were inhibitory at high concentrations (greater than 20 mM). The highest enzyme activity was found in rapidly growing mycelia (glucose-NH4+ or glucose-peptone medium). We discuss the possibility that citric acid accumulation is caused by oxaloacetate and NADH inhibition of the alpha-ketoglutarate dehydrogenase of A. niger.

Meixner-Monori, B; Kubicek, C P; Habison, A; Kubicek-Pranz, E M; Rohr, M

1985-01-01

327

Adaptive Melanin Response of the Soil Fungus Aspergillus niger to UV Radiation Stress at "Evolution Canyon", Mount Carmel, Israel  

PubMed Central

Background Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s) that evolve in direct response to selection, enhancing the organism's fitness. “Evolution Canyon” (EC) in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric “African” slope (AS) receives 200%–800% higher solar radiation than the north-facing, temperate, shady and mesic “European” slope (ES), 200 meters apart. Thus, solar ultraviolet radiation (UVR) is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. Methodology/Principal Findings We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin; in contrast, the sunny strains from the ES displayed higher melanin concentrations. Conclusions/Significance We conclude that melanin in A. niger is an adaptive trait against UVR generated by natural selection.

Singaravelan, Natarajan; Grishkan, Isabella; Beharav, Alex; Wakamatsu, Kazumasa; Ito, Shosuke; Nevo, Eviatar

2008-01-01

328

Increased resistance to 14 alpha-demethylase inhibitors (DMIs) in Aspergillus niger by coexpression of the Penicillium itulicum eburicol 14 alpha-demethylase (cyp51) and the A-niger cytochromeP450 reductase (cprA) genes  

Microsoft Academic Search

In this paper we describe the effects of over-expression of the Penicillium italicum gene encoding eburicol 14?-demethylase (cyp51), in Aspergillus niger strains with one or multiple copies of the gene encoding cytochrome P450 reductase (cprA), on the eburicol 14?-demethylase activity. Eburicol 14?-demethylase activity was determined by measuring the resistance of transformants against some eburicol 14?-demethylase inhibitors (DMIs). DMIs are widely

Brink van den J. M; Nistelrooy van J. G. M; Waard de M. A; Hondel van den C. A. M. J. J; Gorcum van R. F. M

1996-01-01

329

Increased resistance to 14?-demethylase inhibitors (DMIs) in Aspergillus niger by coexpression of the Penicillium italicum eburicol 14?-demethylase ( cyp51) and the A. niger cytochrome P450 reductase ( cprA) genes  

Microsoft Academic Search

In this paper we describe the effects of over-expression of the Penicillium italicum gene encoding eburicol 14?-demethylase (cyp51), in Aspergillus niger strains with one or multiple copies of the gene encoding cytochrome P450 reductase (cprA), on the eburicol 14?-demethylase activity. Eburicol 14?-demethylase activity was determined by measuring the resistance of transformants against some eburicol 14?-demethylase inhibitors (DMIs). DMIs are widely

Hans J. M. Van Den Brink; Hans J. G. M. Van Nistelrooy; Maarten A. De Waard; cees A. M. J. J. Van Den Honde; Robert F. M. Van Gorcom

1996-01-01

330

Aspergillus niger I-1472 and Pycnoporus cinnabarinus MUCL39533, selected for the biotransformation of ferulic acid to vanillin, are also able to produce cell wall polysaccharide-degrading enzymes and feruloyl esterases  

Microsoft Academic Search

The filamentous fungal strains Aspergillus niger I-1472 and Pycnoporus cinnabarinus MUCL39533, previously selected for the bioconversion of ferulic acid to vanillic acid and vanillin respectively, were grown on sugar beet pulp. A large spectrum of polysaccharide-degrading enzymes was produced by A. niger and very few levels of feruloyl esterases were found. In contrast, P. cinnabarinus culture filtrate contained low amount

E Bonnina; M Brunel; Y Gouy; L Lesage-Meessen; M Asther; J.-F Thibault

2001-01-01

331

The Toxic Effect of a Lead Complex with Dl-Cysteine on Aspergillus Niger.  

National Technical Information Service (NTIS)

An investigation of the toxic effect of lead chelate with DL-cysteine on Asp. niger revealed that large swellings appeared on the mycelium. One of the substances formed was uracil which indicates a description of cell permeability in the presence of lead ...

I. V. Zlochevskaya

1969-01-01

332

Evaluation of Aspergillus niger as host for virus-like particle production, using the hepatitis B surface antigen as a model.  

PubMed

The filamentous fungus Aspergillus niger was transformed with the hepatitis B virus S gene encoding the major viral envelope protein under control of the constitutive A. nidulans glyceraldehyde-3-phosphate dehydrogenase ( gpdA) promoter. Approximately seven copies of the expression cassette were integrated on the genome, resulting in high-level transcription of the S gene. Production of the 24-kDa S protein and a 48-kDa S protein dimer in the membrane-associated protein fraction of the recombinant A. niger strain was shown through Western analysis. Electron microscopy of partially purified recombinant S protein revealed the formation of spherical pseudoviral particles with a diameter of 22 nm. The production level of hepatitis B pseudoviral particles was estimated to be 0.4 mg/l culture, which compares favourably with the reported levels initially obtained in yeast, indicating the potential of the Aspergillus expression system as an alternative, cost-effective vaccine production system. PMID:12802503

Plüddemann, Annette; Van Zyl, Willem H

2003-06-11

333

Shifting the pH Profile of Aspergillus niger PhyA Phytase To Match the Stomach pH Enhances Its Effectiveness as an Animal Feed Additive  

Microsoft Academic Search

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

Taewan Kim; Edward J. Mullaney; Jesus M. Porres; Karl R. Roneker; Sarah Crowe; Sarah Rice; Taegu Ko; Abul H. J. Ullah; Catherine B. Daly; Ross Welch; Xin Gen Lei

2006-01-01

334

Effects of N,N -bis(3-aminopropyl)dodecylamine on antioxidant enzyme activities, mitochondrial morphology and metabolism in Aspergillus niger  

Microsoft Academic Search

The activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSP) as well as of succinate dehydrogenase\\u000a (SDG), NADH dehydrogenase (NDG) and fumarate hydratase (FHT) were examined in relation to mitochondrial ultrastructure changes\\u000a inAspergillus niger exposed toN,N-bis(3-aminopropyl)dodecylamine (Apd) that was shown to exhibit fungicidal activity. There was a progressive increase in SOD,\\u000a CAT and GSP activities 1 and 4

E. Ku?niak; A. Wyrwicka; B. Gabara; A. Koziróg; M. Sklodowska

2006-01-01

335

Altering the substrate specificity site of Aspergillus niger PhyB shifts the pH optimum to pH 3.2  

Microsoft Academic Search

Phytases are of biotechnological importance as animal feed additives for their ability to catalyze the hydrolysis of phosphate\\u000a 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 2.5, but has little activity at the commonly observed gastric pH of young\\u000a animals (3.0–3.5). Our objective

Jeremy D. Weaver; Edward J. Mullaney; Xin Gen Lei

2007-01-01

336

Conservation of the Active Site Motif in Aspergillus niger( ficuum) pH 6.0 Optimum Acid Phosphatase and Kidney Bean Purple Acid Phosphatase  

Microsoft Academic Search

Aspergillus niger (ficuum)and the kidney bean purple acid phosphatases retained all the essential amino acids in the active site despite a low degree of total sequence homology. This high degree of homology in the sequence motif ofA. nigerfungal acid phosphatase (Apase6) active site with Kidney bean metallo phosphoesterase (KBPAP) and the absence of the RHGXRXP sequence motif indicates Apase6 to

Edward J. Mullaney; Abul H. J. Ullah

1998-01-01

337

Expression and subcellular compartmentation of Aspergillus niger ?-glucosidase in transgenic tobacco result in an increased insecticidal activity on whiteflies ( Bemisia tabaci)  

Microsoft Academic Search

Transgenic Nicotiana tabacum plants expressing Aspergillus niger ?-glucosidase (EC 3.2.1.21) gene (BGL1) in different subcellular compartments [cell wall (Tcw), endoplasmic reticulum (Ter), and vacuole (Tvc)] were analyzed to study the effects of BGL1 localization on plant growth and plant–insect interaction. Transgenic and non-transgenic plants were grown and characterized in a greenhouse with 25\\/16°C day\\/night temperatures and natural sunlight. Plant insecticidal

Shu Wei; Yaniv Semel; Ben-Ami Bravdo; Henryk Czosnek; Oded Shoseyov

2007-01-01

338

Application of Doehlert designs for water activity, pH, and fermentation time optimization for Aspergillus niger pectinolytic activities production in solid-state and submerged fermentation  

Microsoft Academic Search

The Doehlert design was applied to optimize water activity, pH, and fermentation time conditions for Aspergillus niger 148 pectinolytic activities production in solid-state (SSF) and submerged (SmF) fermentation. The fermentation technique had a great influence on the composition of pectinases produced by the fungus. Production of polygalacturonase was 5-fold higher in SmF than in SSF. However, pectin lyase production was

Viviana M Taragano; Ana M. R Pilosof

1999-01-01

339

Identification of InuR, a new Zn(II)2Cys6 transcriptional activator involved in the regulation of inulinolytic genes in Aspergillus niger  

Microsoft Academic Search

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\\u000a is required for the induced expression of inulinolytic genes. InuR is a member of the fungal specific class of transcription\\u000a factors of the Zn(II)2Cys6 type. Involvement of InuR in inulin and sucrose metabolism was

Xiao-Lian Yuan; Johannes A. Roubos; Cees A. M. J. J. van den Hondel; Arthur F. J. Ram

2008-01-01

340

Aspergillus niger genome-wide analysis reveals a large number of novel alpha-glucan acting enzymes with unexpected expression profiles  

Microsoft Academic Search

The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material.\\u000a A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of ?-amylase,\\u000a glucoamylase and ?-glucosidase enzymes, members of the glycoside hydrolase (GH) families 13, 15

Xiao-Lian Yuan; Rachel M. van der Kaaij; Cees A. M. J. J. van den Hondel; Peter J. Punt; Marc J. E. C. van der Maarel; Lubbert Dijkhuizen; Arthur F. J. Ram

2008-01-01

341

Immobilization of epoxide hydrolase from Aspergillus niger onto DEAE-cellulose: enzymatic properties and application for the enantioselective resolution of a racemic epoxide  

Microsoft Academic Search

Recombinant epoxide hydrolase (EH) from Aspergillus niger can be a very promising tool for the resolution of various racemic epoxides by enantioselective hydrolysis. The enzyme was successfully immobilized by ionic adsorption onto DEAE-cellulose (99% yield, 70% of retention activity). The temperature for maximal activity (40°C) and the activation energy (38.8kJ\\/mol) were similar for both the immobilized and free EHs, whereas

S. Karboune; A. Archelas; R. Furstoss; J. Baratti

2005-01-01

342

High level phytase production by Aspergillus niger NCIM 563 in solid state culture: response surface optimization, up-scaling, and its partial characterization  

Microsoft Academic Search

Phytase production by Aspergillus niger NCIM 563 was optimized by using wheat bran in solid state fermentation (SSF). An integrated statistical optimization approach\\u000a involving the combination of Placket–Burman design (PBD) and Box–Behnken design (BBD) was employed. PBD was used to evaluate\\u000a the effect of 11 variables related to phytase production, and five statistically significant variables, namely, glucose, dextrin,\\u000a NaNO3, distilled

K. Bhavsar; V. Ravi Kumar; J. M. Khire

343

Statistical optimization of cellulases production by Aspergillus niger HQ1 in solid-state fermentation and partial enzymatic characterization of cellulases on hydrolyzing chitosan  

Microsoft Academic Search

Cultivation conditions of cellulases production by Aspergillus niger HQ-1 in solid-state fermentation (SSF) were optimized. Furthermore, partial enzymatic characterization of the crude cellulases\\u000a on hydrolyzing chitosan was studied. The moisture content, cultivation temperature, and initial culture pH were identified\\u000a by Plackett-Burman design (PBD) as the significant factors for cellulases activities. The method of steepest ascent was undertaken\\u000a to determine the

Hui Zhang; Qing Sang; Wenhui Zhang

344

1.68-C Crystal structure of endopolygalacturonase II from Aspergillus niger and identification of active site residues by site-directed mutagenesis  

Microsoft Academic Search

Polygalacturonases specifically hydrolyze polygalacturonate, a major constituent of plant cell wall pectin. To understand the catalytic mechanism and substrate and product specificity of these enzymes, we have solved the x-ray structure of endopolygalacturonase II of Aspergillus niger and we have carried out site-directed mutagenesis studies. The enzyme folds into a right-handed parallel ?-helix with 10 complete turns. The ?-helix is

Bauke W. Dijkstra; Jaap Visser; Klaus-Hasso Schroter; Sylvie Armand; Jacques A. E. Benen; Yovka van Santen

1999-01-01

345

Application of a multi-layer packed-bed reactor to citric acid production in solid-state fermentation using Aspergillus niger  

Microsoft Academic Search

Solid-state fermentation, using the fungus Aspergillus niger, has been employed for the production of citric acid from kumara, a starch-containing root crop. A multi-layer packed-bed reactor was designed and operated in an attempt to understand mass and heat transfer during the fermentation. Although only a limited understanding was obtained, the multi-layer packed-bed reactor improved the mass transfer considerably compared with

M. Y. Lu; I. S. Maddox; J. D. Brooks

1998-01-01

346

Screening of microbes for novel acidic cutinases and cloning and expression of an acidic cutinase from Aspergillus niger CBS 513.88.  

PubMed

Isolates from gardening waste compost and 38 culture collection microbes were grown on agar plates at pH 4.0 with the cutinase model substrate polycaprolactone as a carbon source. The strains showing polycaprolactone hydrolysis were cultivated in liquid at acidic pH and the cultivations were monitored by assaying the p-nitrophenyl butyrate esterase activities. Culture supernatants of four strains were analyzed for the hydrolysis of tritiated apple cutin at different pHs. Highest amounts of radioactive hydrolysis products were detected at pHs below 5. The hydrolysis of apple cutin by the culture supernatants at acidic pH was further confirmed by GC-MS analysis of the hydrolysis products. On the basis of screening, the acidic cutinase from Aspergillus niger CBS 513.88 was chosen for heterogeneous production in Pichia pastoris and for analysis of the effects of pH on activity and stability. The recombinant enzyme showed activity over a broad range of pHs with maximal activity between pH 5.0 and 6.5. Activity could be detected still at pH 3.5. PMID:23540930

Nyyssölä, Antti; Pihlajaniemi, Ville; Järvinen, Riikka; Mikander, Saara; Kontkanen, Hanna; Kruus, Kristiina; Kallio, Heikki; Buchert, Johanna

2013-01-17

347

GpdA-promoter-controlled production of glucose oxidase by recombinant Aspergillus niger using nonglucose carbon sources.  

PubMed

The gpdA-promoter-controlled exocellular production of glucose oxidase (GOD) by recombinant Aspergillus niger NRRL-3 (GOD3-18) during growth on glucose and nonglucose carbon sources was investigated. Screening of various carbon substrates in shake-flask cultures revealed that exocellular GOD activities were not only obtained on glucose but also during growth on mannose, fructose, and xylose. The performance of A. niger NRRL-3 (GOD3-18) using glucose, fructose, or xylose as carbon substrate was compared in more detail in bioreactor cultures. These studies revealed that gpdA-promoter-controlled GOD synthesis was strictly coupled to cell growth. The gpdA-promoter was most active during growth on glucose. However, the unfavorable rapid GOD-catalyzed transformation of glucose into gluconic acid, a carbon source not supporting further cell growth and GOD production, resulted in low biomass yields and, therefore, reduced the advantageous properties of glucose. The total (endo- and exocellular) specific GOD activities were lowest when growth occurred on fructose (only a third of the activity that was obtained on glucose), whereas utilization of xylose resulted in total specific GOD activities nearly as high as reached during growth on glucose. Also, the portion of GOD excreted into the culture fluid reached similar high levels (approximately equal to 90%) by using either glucose or xylose as substrate, whereas growth on fructose resulted in a more pelleted morphology with more than half the total GOD activity retained in the fungal biomass. Finally, growth on xylose resulted in the highest biomass yield and, consequently, the highest total volumetric GOD activity. These results show that xylose is the most favorable carbon substrate for gpdA-promoter-controlled production of exocellular GOD. PMID:11257807

el-Enshasy, H; Hellmuth, K; Rinas, U

2001-01-01

348

Proteomic Analysis of the Secretory Response of Aspergillus niger to D-Maltose and D-Xylose  

PubMed Central

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 ?-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.

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

2011-01-01

349

Corn steep liquor as a nutrition adjunct for the production of Aspergillus niger lipase and hydrolysis of oils thereof.  

PubMed

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

Edwinoliver, N G; Thirunavukarasu, K; Purushothaman, S; Rose, C; Gowthaman, M K; Kamini, N R

2009-11-25

350

Genomic Approaches for Identification of the Biopolymer Degrading Enzyme Network of Aspergillus niger  

Microsoft Academic Search

\\u000a Filamentous fungi share many biological characteristics and processes with the complex higher eukaryotes, including multicellularity,\\u000a development and differentiation programs and intercellular signaling. Their experimental tractability makes them useful model\\u000a systems to study the complexity of the eukaryotic cell. This chapter aims to review the insights into the repertoire of carbohydrate\\u000a modifying enzymes as gained from the genome sequences of Aspergillus

R. M. VAN DER KAAIJ; A. F. J. Ram; P. Schaap; P. J. Punt

351

The Aspergillus niger faeB gene encodes a second feruloyl esterase involved in pectin and xylan degradation and is specifically induced in the presence of aromatic compounds.  

PubMed Central

The faeB gene encoding a second feruloyl esterase from Aspergillus niger has been cloned and characterized. It consists of an open reading frame of 1644 bp containing one intron. The gene encodes a protein of 521 amino acids that has sequence similarity to that of an Aspergillus oryzae tannase. However, the encoded enzyme, feruloyl esterase B (FAEB), does not have tannase activity. Comparison of the physical characteristics and substrate specificity of FAEB with those of a cinnamoyl esterase from A. niger [Kroon, Faulds and Williamson (1996) Biotechnol. Appl. Biochem. 23, 255-262] suggests that they are in fact the same enzyme. The expression of faeB is specifically induced in the presence of certain aromatic compounds, but not in the presence of other constituents present in plant-cell-wall polysaccharides such as arabinoxylan or pectin. The expression profile of faeB in the presence of aromatic compounds was compared with the expression of A. niger faeA, encoding feruloyl esterase A (FAEA), and A. niger bphA, the gene encoding a benzoate-p-hydroxylase. All three genes have different subsets of aromatic compounds that induce their expression, indicating the presence of different transcription activating systems in A. niger that respond to aromatic compounds. Comparison of the activity of FAEA and FAEB on sugar-beet pectin and wheat arabinoxylan demonstrated that they are both involved in the degradation of both polysaccharides, but have opposite preferences for these substrates. FAEA is more active than FAEB towards wheat arabinoxylan, whereas FAEB is more active than FAEA towards sugar-beet pectin.

de Vries, Ronald P; vanKuyk, Patricia A; Kester, Harry C M; Visser, Jaap

2002-01-01

352

The transcriptomic signature of RacA activation and inactivation provides new insights into the morphogenetic network of Aspergillus niger.  

PubMed

RacA is the main Rho GTPase in Aspergillus niger regulating polarity maintenance via controlling actin dynamics. Both deletion and dominant activation of RacA (Rac(G18V)) 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 Rac(G18V). 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, Rac(G18V), 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

Kwon, Min Jin; Nitsche, Benjamin M; Arentshorst, Mark; Jørgensen, Thomas R; Ram, Arthur F J; Meyer, Vera

2013-07-24

353

Synthesis of fructooligosaccharides from Aspergillus niger commercial inulinase immobilized in montmorillonite pretreated in pressurized propane and LPG.  

PubMed

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 2³. Residual activities of 145.1 and 148.5% were observed for LPG (30 bar, 6 h, and depressurization rate of 20 bar?min?¹) and propane (270 bar, 1 h, and depressurization rate of 100 bar?min?¹), 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

de Oliveira Kuhn, Graciele; Rosa, Clarissa Dalla; Silva, Marceli Fernandes; Treichel, Helen; de Oliveira, Débora; Oliveira, J Vladimir

2012-12-29

354

Crystallization and preliminary crystallographic analysis of endo-1,4-beta-xyalanase I from Aspergillus niger.  

PubMed

A family G xylanase from Aspergillus niger has been crystallized using the vapor-diffusion method. Several crystal forms could be obtained using various sodium salts as precipitants. Three of the crystal forms belong to space groups P21, P2(1)2(1)2(1) and P4(3) and have cell parameters of approximately a = b = 85.1, c = 113.6 A and alpha = beta = gamma = 90 degrees. These crystal forms can be converted into one another by flash freezing or macroseeding. A fourth crystal form is cubic (space group P2(1)3) with unit-cell axes of a = b = c = 112.3 A. Data sets for three of the four crystal forms have been collected, extending to a maximum resolution of 2.4 A. The structures of the monoclinic and orthorhombic crystals have been solved by molecular replacement by combining the crystallographic information of the different crystal forms. Refinement of the orthorhombic crystal form is now in progress. PMID:15299682

Krengel, U; Rozeboom, H J; Kalk, K H; Dijkstra, B W

1996-05-01

355

Condition stabilization for Aspergillus niger FCBP-198 and its hyperactive mutants to yield high titres of alpha-amylase.  

PubMed

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

Shafique, Sobiya; Bajwa, Rukhsana; Shafique, Shazia

356

A Possible Role of Aspergillus niger Mitochondrial Cytochrome c in Malachite Green Reduction Under Calcium Chloride Stress.  

PubMed

In previous work, decolorization of malachite green (MG) was studied in Aspergillus niger in the presence and absence of calcium chloride stress. Decolorization took place within 24 h, and a signal transduction process that initiated MG decolorization was suggested to be involved. In the present study, further investigation of the relationship between calcium chloride stress and enhanced MG biodegradation was conducted at the sub-cellular level. MG-NADH reductase activity, a key enzyme in MG decolorization, was produced as decolorization commenced, and enzyme activity increased threefold upon exposure to calcium chloride. Inhibitors of cytochrome p450, Ca(2+) channel activity as well as activity of the signaling protein phosphoinositide 3-kinase were tested. All three activities were inhibited to different extents resulting in reduced MG decolorization. Spectral analysis of the mitochondrial fraction showed a heme signal at 405 nm and A405/A280 ratio that is characteristic of the porphoryin ring of cytochromes. There were no peaks detected for cytochromes a or b, but a shoulder appearing at 550 nm was observed, which suggested that cytochrome c is involved; the absorbance for cytochrome c doubled after calcium chloride stress supporting this idea. MG decolorization took place via a series of demethylation steps, and cytotoxicity analysis revealed a decrease in the toxicity associated with generation of leucomalachite green. PMID:23737340

Gomaa, Ola M; Selim, Nabila S; Linz, John E

2013-06-01

357

Optimization of date syrup for enhancement of the production of citric acid using immobilized cells of Aspergillus niger  

PubMed Central

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 0.1 g/l of KH2PO4 was added to the medium of date syrup. The addition of magnesium sulfate at the rate of 0.20 g/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 24 days when each cycle continued for 144 h. 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.

Mostafa, Yasser S.; Alamri, Saad A.

2012-01-01

358

A tanks-in-series bioreactor to simulate macromolecule-laden wastewater pretreatment under sewer conditions by Aspergillus niger.  

PubMed

Sewers are typically a means of transporting wastewater to a treatment facility, with little biotransformation of the soluble polymeric organic matter by suspended biomass. In the interest of providing an effective pretreatment of wastewater in a sewer network, it is necessary to design an accurate tool simulating sewer conditions and introduce an appropriate biomass for macromolecular pollutant degradation. Such a model reactor was built using a tanks-in-series design and the degradation of a polysaccharide (starch) by Aspergillus niger MUCL 28817 was studied. Starch degradation and the accumulation of intermediates (hydrolysis fragments) in the individual reactors were quantified under transient conditions, at a mean hydraulic residence time of 17 h. Starch was degraded by 90% in this reactor system and an accumulation of oligosaccharides with molecular weight lower than 1,000 Da was observed. These results may be helpful in the development of wastewater treatment in sewers and in the alleviation of the burden on undersized wastewater treatment systems. PMID:12405402

Coulibaly, Lacina; Naveau, Henry; Agathos, Spiros N

2002-09-01

359

Glucoamylases G1 and G2 from Aspergillus niger are synthesized from two different but closely related mRNAs.  

PubMed Central

By the use of glucoamylase-specific synthetic oligodeoxyribonucleotides and molecular cloning of cDNA synthesized from Aspergillus niger total poly(A) + RNA, the primary structure of the glucoamylase G1 mRNA was determined. Glucoamylase G1 is synthesized as a precursor of 640 amino acid residues containing a putative signal peptide of 18 residues, a short propeptide of six residues and the 616 residues long mature enzyme. In vitro translations of mRNA and immunoprecipitations with glucoamylase-specific antisera showed that two glucoamylase polypeptides are synthesized. The larger form with an apparent mol. wt. of 71 000 corresponds to the precursor of glucoamylase G1, and the shorter form with an apparent mol. wt. of 61 000 corresponds to the precursor of glucoamylase G2. From the nucleotide sequencing data of several glucoamylase-specific cDNA recombinants it is shown that the G1 mRNA contains a 169 bp long intervening sequence that can be spliced out to generate a G2 mRNA. Only the 3' part of the G1 mRNA is modified by this splicing event. This kind of differential mRNA processing to give different protein products from one primary transcript has previously only been demonstrated in higher eukaryotes. Images Figure 1. Fig. 2.

Boel, E; Hjort, I; Svensson, B; Norris, F; Norris, K E; Fiil, N P

1984-01-01

360

Production of high concentrations of ethanol from inulin by simultaneous saccharification and fermentation using Aspergillus niger and Saccharomyces cerevisiae.  

PubMed Central

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.

Ohta, K; Hamada, S; Nakamura, T

1993-01-01

361

Detection of Aflr Gene and Toxigenicity of Aspergillus flavus Group Isolated from Patients with Fungal Sinusitis  

Microsoft Academic Search

Background: Aspergillus flavus is the second most important Aspergillus species causing human infections particularly fungal sinusitis. Since little is known about aflatoxin producing ability of clinical isolates, this study was undertaken to de- tect the aflatoxigenic isolates amongst these isolates. Methods: A total of 23 isolates of A. spp. which were recovered from patients proved to have fungal sinusitis by

P Dehghan; F Zaini; S Rezaei; A Jebali; P Kordbacheh; M Mahmoudi

362

Induction, production, repression, and de-repression of exoglucanase synthesis in Aspergillus niger.  

PubMed

The influence of carbon and nitrogen sources on the production of cellulases was investigated. The enzyme production was variable according to the carbon source. Levels of beta-cellobiohydrolase (CBH) were minimal in the presence of even low concentrations of glucose. Enzyme production was stimulated by other carbohydrates. The enzyme is subject to carbon source control by easily metabolizable sugars. Wheat bran and cellulose were the most effective promoters of beta-cellobiohydrolase and filter paperase (FPase) activities respectively, followed by rice bran. Exogenously supplied glucose inhibited the synthesis of the enzyme in cultures of A. niger growing on wheat bran. In defined medium with cellobiose, the cellobiohydrolase titres were 2- to 110-fold higher with cells growing on monomeric sugars and 1.5 times higher than cells growing on other disaccharides. It appeared that synthesis of beta-cellobiohydrolase varied under an induction mechanism, and a repression mechanism which changed the rate of synthesis of beta-cellobiohydrolase and FPase in induced over non-induced cultures. In this organism, substantial synthesis of beta-cellobiohydrolase can be induced by cellobiose, cellodextrin, cellulose or cellulose and hemi-cellulose containing substrates which showed low volumetric substrate uptake rate. The organism required limiting concentration of carbon, nitrogen or phosphorous for production of beta-cellobiohydrolase and FPase. During growth of A. niger on wheat bran, maximum volumetric productivities (Qp) of beta-cellobiohydrolase and FPase were 39.6 and 32.5 IU/lh and were significantly higher than the values reported for some other potent fungi and bacteria. The addition of actinomycin D (a repressor of transcription) and cycloheximide, (a repressor of translation) completely repressed CBH/FPase biosynthesis, suggested that the regulation of CBH synthesis in this organism occurs at both transcriptional and translational level. Thermodynamic studies revealed that the culture exerted protection against thermal inactivation when exposed to different fermentation temperatures. PMID:15182839

Hanif, Atif; Yasmeen, Amber; Rajoka, M I

2004-09-01

363

In vitro activities of amphotericin B and AmBisome against Aspergillus isolates recovered from Italian patients treated for haematological malignancies.  

PubMed

Although there is evidence that liposomal amphotericin B (AmBisome) is non-inferior to amphotericin B (AmB) in terms of in vivo efficacy, in vitro data regarding the activity of AmBisome against clinical isolates of Aspergillus are rare. In this study, the susceptibilities to AmB and AmBisome of 103 Aspergillus complex isolates (48 Aspergillus flavus, 33 Aspergillus fumigatus, 13 Aspergillus terreus and 9 Aspergillus niger) recovered from haematological patients with invasive infection were compared. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution (BMD) method according to the Clinical and Laboratory Standards Institute (CLSI), whilst AmB susceptibility was also determined by Etest. Using a susceptible/resistant MIC cut-off of 1mg/L, all A. fumigatus and A. niger complexes isolates were susceptible to both AmB and AmBisome. In contrast, 38.5% and 30.8% of the A. terreus complex isolates were resistant to AmB and AmBisome, respectively, with good agreement between BMD and Etest methods. With respect to A. flavus complex isolates, 43.7% and 16.7% were resistant by the BMD method to AmBisome and AmB, respectively. For isolates with discrepant results, AmB MICs obtained by Etest were higher than those obtained for AmB by the BMD method and they were closer to those obtained for AmBisome by BMD. Aspergillus flavus AmB MICs ranged from 0.5 mg/L to 2 mg/L by the BMD method and from 1 mg/L to >16 mg/L by the Etest method, and AmBisome MICs ranged from 0.06 mg/L to >16 mg/L by the BMD method. Etest appears to be superior to the CLSI BMD method using AmB in detecting AmB resistance of Aspergillus spp., although the CLSI BMD method might be a suitable procedure if AmBisome is used as the test drug. PMID:22429723

Colozza, Camilla; Posteraro, Brunella; Santilli, Stefania; De Carolis, Elena; Sanguinetti, Maurizio; Girmenia, Corrado

2012-03-17

364

Isolation and characterization of an elastinolytic proteinase from Aspergillus flavus.  

PubMed Central

An elastinolytic proteinase of Aspergillus flavus has been isolated to homogeneity, and its physical and biochemical properties have been characterized. Two purification protocols were compared; an initial step of ion-exchange chromatography was found to be equivalent to ammonium sulfate precipitation at neutral pH. A combination of gel filtration and adsorption chromatographies on the resultant crude enzyme produced highly purified elastase with yields of 5 to 10%. The enzyme is a 23-kilodalton protein with a pI of 7.6. The enzyme activity is markedly inhibited by numerous metal ions. Aspergillus elastase appears to be a metalloproteinase EC 3.4.24.X), as determined by its sensitivity to 1,10-phenanthroline. Images

Rhodes, J C; Amlung, T W; Miller, M S

1990-01-01

365

Customization of Aspergillus niger Morphology Through Addition of Talc Micro Particles  

PubMed Central

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 (Figure 1). Various process parameters and ingredients are known to influence fungal morphology 1. 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 2-6. 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 (Figure 1) 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 7-9. Therefore, the quantification of glucose after adding sucrose implies the amount of produced ?-fructofuranosidase. Glucose quantification is made by a GOD/POD-Assay 10, 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) 11, which enables a comprehensive characterization of fungal morphology. The close correlation of the Morphology number and productivity are highlighted by mathematical regression.

Wucherpfennig, Thomas; Lakowitz, Antonia; Driouch, Habib; Krull, Rainer; Wittmann, Christoph

2012-01-01

366

Customization of Aspergillus niger morphology through addition of talc micro particles.  

PubMed

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

Wucherpfennig, Thomas; Lakowitz, Antonia; Driouch, Habib; Krull, Rainer; Wittmann, Christoph

2012-03-15

367

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...

368

Degradation of Xylan to d-Xylose by Recombinant Saccharomyces cerevisiae Coexpressing the Aspergillus niger ?-Xylosidase (xlnD) and the Trichoderma reesei Xylanase II (xyn2) Genes  

PubMed Central

The ?-xylosidase-encoding xlnD gene of Aspergillus niger 90196 was amplified by the PCR technique from first-strand cDNA synthesized on mRNA isolated from the fungus. The nucleotide sequence of the cDNA fragment was verified to contain a 2,412-bp open reading frame that encodes a 804-amino-acid propeptide. The 778-amino-acid mature protein, with a putative molecular mass of 85.1 kDa, was fused in frame with the Saccharomyces cerevisiae mating factor ?1 signal peptide (MF?1s) to ensure correct posttranslational processing in yeast. The fusion protein was designated Xlo2. The recombinant ?-xylosidase showed optimum activity at 60°C and pH 3.2 and optimum stability at 50°C. The Ki(app) value for d-xylose and xylobiose for the recombinant ?-xylosidase was determined to be 8.33 and 6.41 mM, respectively. The XLO2 fusion gene and the XYN2 ?-xylanase gene from Trichoderma reesei, located on URA3-based multicopy shuttle vectors, were successfully expressed and coexpressed in the yeast Saccharomyces cerevisiae under the control of the alcohol dehydrogenase II gene (ADH2) promoter and terminator. These recombinant S. cerevisiae strains produced 1,577 nkat/ml of ?-xylanase activity when expressing only the ?-xylanase and 860 nkat/ml when coexpressing the ?-xylanase with the ?-xylosidase. The maximum ?-xylosidase activity was 5.3 nkat/ml when expressed on its own and 3.5 nkat/ml when coexpressed with the ?-xylanase. Coproduction of the ?-xylanase and ?-xylosidase enabled S. cerevisiae to degrade birchwood xylan to d-xylose.

La Grange, D. C.; Pretorius, I. S.; Claeyssens, M.; van Zyl, W. H.

2001-01-01

369

Involvement of the opportunistic pathogen Aspergillus tubingensis in osteomyelitis of the maxillary bone: a case report  

PubMed Central

Background Aspergillus tubingensis is a black Aspergillus belonging to the Aspergillus section Nigri, which includes species that morphologically resemble Aspergillus niger. Recent developments in species determination have resulted in clinical isolates presumed to be Aspergillus niger being reclassified as Aspergillus tubingensis by sequencing. We present a report of a patient with an osteomyelitis of the maxillary bone with a probable invasive Aspergillus tubingensis infection. Case presentation We describe an immune compromised patient suffering from osteomyelitis of the maxillary bone after tooth extraction. The osteomyelitis probably resulted in dentogenic pansinusitis presenting as an acute ethmoiditis. Histologic examination of biopsy samples showed osteomyelitis, and inflammation of the surrounding connective tissue. Cultures of the alveolar wound grew Aspergillus tubingensis. The patient was treated with liposomal amphoterocin B, which was changed to oral treatment with voriconazole based on susceptibility testing (MIC for voriconazole was 1 ?g/ml). Conclusion This case shows that Aspergillus tubingensis may have the potential to cause severe invasive infections in immunocompromised hosts. A larger proportion of Aspergillus tubingensis isolates are less susceptible to azoles compared to Aspergillus niger. Therefore, correct species identification and susceptibility testing is crucial for the choice of anti-fungal treatment, screening of azole resistance, and characterization of the pathogenic potential of the various species within Aspergillus section Nigri.

2013-01-01

370

Application of a statistical design to the optimization of culture medium for ?-amylase production by Aspergillus niger ATCC 16404 grown on orange waste powder  

Microsoft Academic Search

The production optimization of ?-amylase (E.C.3.2.1.1.) from Aspergillus niger ATCC 16404 fungus is obtained with statistical experimental designs. The methodology was based on the Plackett–Burman design (N=12) [12 experiments and 11 factors in which seven are real ones (agitation, pH, starch, yeast extract, “corn steep liquor”, CaCl2, and salts: MgCl2, 6H2O, MnSO4 and FeSO4, 7H2O) and four errors]. This design

S. Djekrif-Dakhmouche; Z. Gheribi-Aoulmi; Z. Meraihi; L. Bennamoun

2006-01-01

371

Cloning and characterization of a tyrosinase gene from the white-rot fungus Pycnoporus sanguineus , and overproduction of the recombinant protein in Aspergillus niger  

Microsoft Academic Search

A new tyrosinase-encoding gene (2,204 bp) and the corresponding cDNA (1,857 nucleotides) from the white-rot fungus Pycnoporus sanguineus BRFM49 were cloned. This gene consisted of seven exons and six introns and encoded a predicted protein of 68 kDa, exceeding\\u000a the mature tyrosinase by 23 kDa. P. sanguineus tyrosinase cDNA was over-expressed in Aspergillus niger, a particularly suitable fungus for heterologous expression of proteins

Sonia Halaouli; Eric Record; Laurence Casalot; Moktar Hamdi; Jean-Claude Sigoillot; Marcel Asther; Anne Lomascolo

2006-01-01

372

Fungal Gene Expression on Demand: an Inducible, Tunable, and Metabolism-Independent Expression System for Aspergillus niger?†  

PubMed Central

Filamentous fungi are the cause of serious human and plant diseases but are also exploited in biotechnology as production platforms. Comparative genomics has documented their genetic diversity, and functional genomics and systems biology approaches are under way to understand the functions and interaction of fungal genes and proteins. In these approaches, gene functions are usually inferred from deletion or overexpression mutants. However, studies at these extreme points give only limited information. Moreover, many overexpression studies use metabolism-dependent promoters, often causing pleiotropic effects and thus limitations in their significance. We therefore established and systematically evaluated a tunable expression system for Aspergillus niger that is independent of carbon and nitrogen metabolism and silent under noninduced conditions. The system consists of two expression modules jointly targeted to a defined genomic locus. One module ensures constitutive expression of the tetracycline-dependent transactivator rtTA2S-M2, and one module harbors the rtTA2S-M2-dependent promoter that controls expression of the gene of interest (the Tet-on system). We show here that the system is tight, responds within minutes after inducer addition, and allows fine-tuning based on the inducer concentration or gene copy number up to expression levels higher than the expression levels of the gpdA promoter. We also validate the Tet-on system for the generation of conditional overexpression mutants and demonstrate its power when combined with a gene deletion approach. Finally, we show that the system is especially suitable when the functions of essential genes must be examined.

Meyer, Vera; Wanka, Franziska; van Gent, Janneke; Arentshorst, Mark; van den Hondel, Cees A. M. J. J.; Ram, Arthur F. J.

2011-01-01

373

Tailoring fungal morphology of Aspergillus niger MYA 135 by altering the hyphal morphology and the conidia adhesion capacity: biotechnological applications.  

PubMed

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 ?-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?

Colin, Verónica Leticia; Baigorí, Mario Domingo; Pera, Licia María

2013-05-20

374

Fungal gene expression on demand: an inducible, tunable, and metabolism-independent expression system for Aspergillus niger.  

PubMed

Filamentous fungi are the cause of serious human and plant diseases but are also exploited in biotechnology as production platforms. Comparative genomics has documented their genetic diversity, and functional genomics and systems biology approaches are under way to understand the functions and interaction of fungal genes and proteins. In these approaches, gene functions are usually inferred from deletion or overexpression mutants. However, studies at these extreme points give only limited information. Moreover, many overexpression studies use metabolism-dependent promoters, often causing pleiotropic effects and thus limitations in their significance. We therefore established and systematically evaluated a tunable expression system for Aspergillus niger that is independent of carbon and nitrogen metabolism and silent under noninduced conditions. The system consists of two expression modules jointly targeted to a defined genomic locus. One module ensures constitutive expression of the tetracycline-dependent transactivator rtTA2(S)-M2, and one module harbors the rtTA2(S)-M2-dependent promoter that controls expression of the gene of interest (the Tet-on system). We show here that the system is tight, responds within minutes after inducer addition, and allows fine-tuning based on the inducer concentration or gene copy number up to expression levels higher than the expression levels of the gpdA promoter. We also validate the Tet-on system for the generation of conditional overexpression mutants and demonstrate its power when combined with a gene deletion approach. Finally, we show that the system is especially suitable when the functions of essential genes must be examined. PMID:21378046

Meyer, Vera; Wanka, Franziska; van Gent, Janneke; Arentshorst, Mark; van den Hondel, Cees A M J J; Ram, Arthur F J

2011-03-04

375

Effect of increasing inoculum sizes of Aspergillus hyphae on MICs and MFCs of antifungal agents by broth microdilution method  

Microsoft Academic Search

In order to investigate the influence of different hyphal inoculum sizes on minimal inhibition concentrations (MICs) and minimum fungicidal concentrations (MFCs) of amphotericin B (AMB), voriconazole and itraconazole, five isolates each of Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger and Aspergillus terreus were studied using a broth microdilution method. Three inoculum sizes were used: 1×103–5×103, 1×104–5×104 and 1×105–5×105 cfu\\/ml. MICs and

Cornelia Lass-Flörl; C Speth; G Kofler; M. P Dierch; E Gunsilius; R Würzner

2003-01-01

376

5-Demethoxyfumagillol, a potent angiogenesis inhibitor isolated from Aspergillus fumigatus.  

PubMed

A novel angiogenesis inhibitor, 5-demethoxyfumagillol (1), was obtained by isolation, purification and saponification of cultured broth of Aspergillus fumigatus. The structure was assigned as (3R,4R,6R)-4-[(2R,3R)-2-methyl-3-(3-methyl-but-2-enyl)-oxiranyl]-1-oxa-spiro[2,5]octan-6-ol (1) by spectroscopic analysis and confirmed by independent synthesis from fumagillol (3). In addition, 6-O-(chloroacetylcarbamoyl)-5-demethoxyfumagillol (7) showed a potential anti-angiogenic activity in CAPE cells in vitro. PMID:15056962

Kim, Deukjoon; Min, Jaeki; Ahn, Soon Kil; Lee, Hong Woo; Choi, Nam Song; Moon, Seung Kee

2004-04-01

377

Isolation and Properties of Pectinases from the Fungus Aspergillus japonicus  

Microsoft Academic Search

Using anion-exchange chromatography on different carriers and phenyl-Sepharose hydrophobic chromatography, five pectolytic enzymes were isolated from the culture liquid of a mutant strain of Aspergillus japonicus: two endo-polygalacturonases (I and II, 38 and 65 kD, pI5.6 and 3.3), pectin lyase (50 kD, pI3.8), and two pectinesterases (I and II) with similar molecular weights (46 and 47 kD) and the same

M. V. Semenova; S. G. Grishutin; A. V. Gusakov; O. N. Okunev; A. P. Sinitsyn

2003-01-01

378

Leporizines a-C: epithiodiketopiperazines isolated from an Aspergillus species.  

PubMed

Three new compounds named leporizines A-C (1-3) have been isolated from an Aspergillus sp. strain. Their structures were elucidated by analysis of 1D and 2D NMR spectra. Leporizines A and B were isolated during dereplication of hits from a high-throughput screening campaign for correctors of the cystic fibrosis transmembrane conductance regulator (CFTR), and leporizine C was isolated while preparing additional material for characterization of leporizines A and B. CFTR activity observed for leporizines A and B was highly correlated with cell toxicity and was determined to be a nonspecific effect. Leporizine C was not cytotoxic to cells and did not elicit a response in the CFTR assays. To the best of our knowledge, leporizines A-C represent the first examples of this unusual epithiodiketopiperazine skeleton. PMID:24050204

Reategui, Ricardo; Rhea, Joshua; Adolphson, Janet; Waikins, Kathryn; Newell, Ryan; Rabenstein, John; Mocek, Ulla; Luche, Michele; Carr, Grant

2013-09-19

379

Isolation and Identification of Indigenous Aspergillus oryzae for Saccharification of Rice Starch  

Microsoft Academic Search

A study was undertaken to isolate an indigenous Aspergillus oryzae strain for use in saccharification of high amylose rice starch. Bread, black gram, soya grains, 'kevum', and cooked rice samples assumed to be contaminated with Aspergillus oryzae were used in the isolation. Ten pure cultures obtained by culturing and sub- culturing on Potato Dextrose Agar (PDA) were maintained on PDA

S. S. Sooriyamoorthy; K. F. S. T. Silva; M. H. W. Gunawardhane; C. K. Illeperuma

380

Comparison of four media for the isolation of Aspergillus flavus group fungi  

Microsoft Academic Search

Four agar media used to isolate aflatoxin producing fungi were compared for utility in isolating fungi in theAspergillus flavus group from agricultural soils collected in 15 fields and four states in the southern United States. The four media wereAspergillus flavus andparasiticus Agar (AFPA, 14), the rose bengal agar described by Bell and Crawford (BCRB; 3), a modified rose bengal agar

Peter J. Cotty

1994-01-01

381

Highly active, citrate inhibition resistant form of Aspergillus niger 6-phosphofructo-1-kinase encoded by a modified pfkA gene.  

PubMed

In Aspergillus niger cells spontaneous posttranslational modification of 6-phosphofructo-1-kinase (PFK1) occurs. In a two step process the native enzyme (85kDa) is first cleaved to an inactive fragment (49kDa) that regains its activity after phosphorylation of the protein. The shorter PFK1 fragment exhibits changed kinetics, such as resistance to citrate inhibition. In order to avoid spontaneous complex posttranslational modification, modified gene was prepared encoding an active shorter PFK1 fragment. Since no appropriate microbial strains with disrupted native pfkA genes were available, Aspergillus niger strain with reduced likelihood for spontaneous posttranslational modification of PFK1 has been chosen for in vivo tests. First, the appropriate length of a truncated gene was defined after a number of enzymes encoded by genes of different lengths had been tested. After adding sodium azide to the medium, phosphorylation was induced in the transformed hyphae to activate the shorter fragments which were subsequently screened for changed PFK1 kinetics. In the second step the responsible threonine residue was replaced with glutamic acid to elude the need for phosphorylation. An active shorter PFK1 fragment, resistant to citrate inhibition and activated to a higher level by fructose-2,6-bisphosphate with respect to the native enzyme was encoded directly from the modified gene. PMID:19379783

Capuder, Maja; Solar, Tina; Bencina, Mojca; Legisa, Matic

2009-04-18

382

Aspergillus niger genome-wide analysis reveals a large number of novel alpha-glucan acting enzymes with unexpected expression profiles  

PubMed Central

The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material. A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of ?-amylase, glucoamylase and ?-glucosidase enzymes, members of the glycoside hydrolase (GH) families 13, 15 and 31, respectively. In this study we have combined analysis of the genome sequence of A. niger CBS 513.88 with microarray experiments to identify novel enzymes from these families and to predict their physiological functions. We have identified 17 previously unknown family GH13, 15 and 31 enzymes in the A. niger genome, all of which have orthologues in other aspergilli. Only two of the newly identified enzymes, a putative ?-glucosidase (AgdB) and an ?-amylase (AmyC), were predicted to play a role in starch degradation. The expression of the majority of the genes identified was not induced by maltose as carbon source, and not dependent on the presence of AmyR, the transcriptional regulator for starch degrading enzymes. The possible physiological functions of the other predicted family GH13, GH15 and GH31 enzymes, including intracellular enzymes and cell wall associated proteins, in alternative ?-glucan modifying processes are discussed. Electronic supplementary material The online version of this article (doi:10.1007/s00438-008-0332-7) contains supplementary material, which is available to authorized users.

Yuan, Xiao-Lian; van der Kaaij, Rachel M.; van den Hondel, Cees A. M. J. J.; Punt, Peter J.; van der Maarel, Marc J. E. C.; Dijkhuizen, Lubbert

2008-01-01

383

Control of Aspergillus niger infection in varieties of Arachis hypogeae L. by supplementation of zinc ions during seed germination  

Microsoft Academic Search

Three varieties of Arachis hypogeae, GG 11, GG 20 and GG 24, were compared for resistance against A. niger. GG 20 showed the least disease severity. Infection with A. niger resulted in a rapid increase in NADPH oxidase, Glutathione reductase (GR) and salicylic acid in all the three varieties, indicating hyper increase of reactive oxygen species (ROS) and activation of

Harsur M. Jajda; Vasudev R. Thakkar

2012-01-01

384

Identification of the galactitol dehydrogenase, LadB, that is part of the oxido-reductive D-galactose catabolic pathway in Aspergillus niger.  

PubMed

For the catabolism of D-galactose three different metabolic pathways have been described in filamentous fungi. Apart from the Leloir pathway and the oxidative pathway, there is an alternative oxido-reductive pathway. This oxido-reductive pathway has similarities to the metabolic pathway of L-arabinose, and in Trichoderma reesei (Hypocrea jecorina) and Aspergillus nidulans the same enzyme is employed for the oxidation of L-arabitol and galactitol. Here we show evidence that in Aspergillus niger L-arabitol dehydrogenase (LadA) is not involved in the D-galactose metabolism; instead another dehydrogenase encoding gene, ladB, is induced in response to D-galactose and galactitol and functions as a galactitol dehydrogenase. Deletion of ladB in A. niger results in growth arrest on galactitol and significantly slower growth on D-galactose supplemented with a small amount of D-xylose. D-galactose alone cannot be utilised by A. niger and the addition of D-xylose stimulates growth on D-galactose via transcriptional activation of the D-xylose-inducible reductase gene, xyrA. XyrA catalyses the first step of the D-galactose oxido-reductive pathway, the reduction to galactitol, which in turn seems to be an inducer of the downstream genes such as LadB. The deletion of xyrA results in reduced growth on D-galactose. The ladB gene was expressed in the heterologous host Saccharomyces cerevisiae and the tagged and purified enzyme characterised. LadB and LadA have similar in vitro activity with galactitol. It was confirmed that the reaction product of the LadB reaction from galactitol is L-xylo-3-hexulose as in the case of the T. reesei Lad1. PMID:22155165

Mojzita, Dominik; Koivistoinen, Outi M; Maaheimo, Hannu; Penttilä, Merja; Ruohonen, Laura; Richard, Peter

2011-11-30

385

Genetic diversity among clinical and environmental isolates of Aspergillus fumigatus.  

PubMed Central

To determine if cases of invasive aspergillosis (IA) were caused by strains of Aspergillus fumigatus with unique characteristics, strains from immunosuppressed patients with IA were compared to strains obtained from sputa of patients with cystic fibrosis and to strains from the environment. An extremely high genomic diversity was observed among the 879 strains typed by Southern blotting with a retrotransposon-like element from A. fumigatus (C. Neuvéglise, J. Sarfati, J. P. Latgé, and S. Paris, Nucleic Acids Res. 24:1428-1434, 1996). Analysis of Southern blot hybridization patterns showed the absence of clustering between environmental isolates and clinical isolates from patients with IA or cystic fibrosis. In addition, strains could not be clustered depending on their geographical location. This study implies that practically any strain of A. fumigatus is potentially pathogenic and can provoke a case of IA when it encounters a favorable environment in an immunosuppressed host.

Debeaupuis, J P; Sarfati, J; Chazalet, V; Latge, J P

1997-01-01

386

Morphological development of Aspergillus niger in submerged citric acid fermentation as a function of the spore inoculum level. Application of neural network and cluster analysis for characterization of mycelial morphology  

Microsoft Academic Search

BACKGROUND: Although the citric acid fermentation by Aspergillus niger is one of the most important industrial microbial processes and various aspects of the fermentation appear in a very large number of publications since the 1950s, the effect of the spore inoculum level on fungal morphology is a rather neglected area. The aim of the presented investigations was to quantify the

Maria Papagianni; Michael Mattey

2006-01-01

387

Heterogeneity in liquid shaken cultures of Aspergillus niger inoculated with melanised conidia or conidia of pigmentation mutants.  

PubMed

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 (3.2-3.3 ?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 (790-858 ?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

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; Wösten, H A B

2012-09-14

388

Heavy-metal-induced Inhibition of Aspergillus niger nitrate reductase: Applications for Rapid Contaminant Detection in Aqueous Samples  

SciTech Connect

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.

Apel, William Arnold; Aiken, Abigail Marie; Peyton, Brent Michael; Petersen, James N.

2003-03-01

389

Identification of amino acid residues critical for catalysis and stability in Aspergillus niger family 1 pectin lyase A.  

PubMed Central

Site-directed-mutagenesis studies were performed on family 1 pectin lyase A (PL1A) from Aspergillus niger to gain insight into the reaction mechanism for the pectin lyase-catalysed beta-elimination cleavage of methylesterified polygalacturonic acid and to stabilize the enzyme at slightly basic pH. On the basis of the three-dimensional structures of PL1A [Mayans, Scott, Connerton, Gravesen, Benen, Visser, Pickersgill and Jenkins (1997) Structure 5, 677-689] and the modelled enzyme-substrate complex of PL1B [Herron, Benen, Scavetta, Visser and Jurnak (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 8762-8769], Asp154, Arg176, Arg236 and Lys239 were mutagenized. Substituting Arg236 with alanine or lysine rendered the enzyme completely inactive, and mutagenesis of Arg176 and Lys239 severely affected catalysis. The Asp154-->Arg and Asp154-->Glu mutant enzymes were only moderately impaired in respect of catalysis. The results strongly indicate that Arg236, which is sandwiched between Arg176 and Lys239, would initiate the reaction upon enzyme-substrate interaction, through the abstraction of the proton at C5 of the galacturonopyranose ring. The positively charged residues Arg176 and Lys239 are responsible for lowering the p K a of Arg236. Arg176 and Lys239 are maintained in a charged state by interacting with Asp154 or bulk solvent respectively. The deprotonation of the Asp186-Asp221 pair was proposed to be responsible for a pH-driven conformational change of PL1A [Mayans, Scott, Connerton, Gravesen, Benen, Visser, Pickersgill and Jenkins (1997) Structure 5, 677-689]. Substitution of Asp186 and Asp221 by Asn186 and Asn221 was expected to stabilize the enzyme. However, the Asp186-->Asn/Asp221-->Asn enzyme appeared less stable than the wild-type enzyme, even at pH 6.0, as evidenced by fluorescence studies. This demonstrates that the pH-dependent conformational change is not driven by deprotonation of the Asp186-Asp221 pair.

Sanchez-Torres, Paloma; Visser, Jaap; Benen, Jacques A E

2003-01-01

390

Bioprocess and biotecnology: effect of xylanase from Aspergillus niger and Aspergillus flavus on pulp biobleaching and enzyme production using agroindustrial residues as substract.  

PubMed

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 50°C, the xylanase of A. niger retained over 85% activity with 2 h of incubation, and A. flavus had a half-life of more than 75 minutes. At 55°C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45 minutes. 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

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

2013-08-13

391

Isolation and toxigenicity of Aspergillus fumigatus from moldy silage.  

PubMed

Thirty-nine silage samples were collected from various silos on Terceira Island in the Azores. Samples were examined for the presence of total fungi, and isolates of Aspergillus fumigatus were analyzed for their ability to produce fumitremorgens B and C, fumigaclavines B and C, and gliotoxin. Thirty-four silage samples (87%) were contaminated with fungi, and A. fumigatus was isolated from 27 samples (69%). Samples that were taken from the surface of silos had significantly higher populations of both total fungi and A. fumigatus than did samples taken from the middle of silos. Analysis of 27 A. fumigatus isolates (one representing each positive sample) showed that 59.3% produced fumitremorgen B; 33.3% produced fumitremorgen C; 29.6% produced fumigaclavine B; 7.4% produced fumigaclavine C; and 11.1% produced gliotoxin. Fifty-two percent of the isolates produced multiple toxins, and 25.9% did not produce any of these toxins. Gliotoxin and fumigaclavine C were always produced in combination with other toxins. Because of the demonstrated potential of these A. fumigatus isolates to produce mycotoxins, it is important to properly construct and manage silos to prevent their contamination with A. fumigatus. PMID:12733634

dos Santos, Valentina Melo; Dorner, Joe W; Carreira, Fátima

2003-01-01

392

Analysis of functional xylanases in xylan degradation by Aspergillus niger E-1 and characterization of the GH family 10 xylanase XynVII.  

PubMed

Xylanases produced by Aspergillus niger are industrially important and many types of xylanases have been reported. Individual xylanases have been well studied for their enzymatic properties, gene cloning, and heterologous expression. However, less attention has been paid to the relationship between xylanase genes carried on the A. niger genome and xylanases produced by A. niger strains. Therefore, we examined xylanase genes encoded on the genome of A. niger E-1 and xylanases produced in culture. Seven putative xylanase genes, xynI-VII (named in ascending order of the molecular masses of the deduced amino acid sequences), were amplified from the strain E-1 genome using primers designed from the genome sequence of A. niger CBS 513.88 by PCR and phylogenetically classified into three clusters. Additionally, culture supernatant analysis by DE52 anion-exchange column chromatography revealed that this strain produced three xylanases, XynII, XynIII, and XynVII, which were identified by N-terminal amino acid sequencing and MALDI-TOF-MS analyses, in culture when gown in 0.5% xylan medium supplemented with 50 mM succinate. Furthermore, XynVII, the only GH family 10 xylanase in A. niger E-1, was purified and characterized. The purified enzyme showed a single band with a molecular mass of 35 kDa by SDS-PAGE. The highest activity of purified XynVII was observed at 55°C and pH 5.5. The enzyme was stable in the broad pH range of 3-10 and up to 60°C and was resistant to most metal ions and modifying regents. XynVII showed high specificity against beechwood xylan with K m and V max values of 2.8 mg mL(-1) and 127 ?mol min(-1)mg(-1), respectively. TLC and MALDI-TOF-MS analyses showed that the final hydrolyzed products of the enzyme from beechwood xylan were xylose, xylobiose, and xylotriose substituted with a 4-o-metylglucuronic acid residue. PMID:24083101

Takahashi, Yui; Kawabata, Hiroaki; Murakami, Shuichiro

2013-09-09

393

In Vitro Activity of the Echinocandin Antifungal Agent LY303,366 in Comparison with Itraconazole and Amphotericin B against Aspergillus spp  

Microsoft Academic Search

LY303,366 (LY) is a novel derivative of the echinocandin class of antifungal agents. The in vitro activities of LY, itraconazole (ITZ), and amphotericin B (AMB) were assessed against 60 Aspergillus isolates, including 35 isolates of A. fumigatus, eight isolates of A. terreus, eight isolates of A. flavus, eight isolates of A. niger and one isolate of A. nidulans. Four A.

KAREN L. OAKLEY; CAROLINE B. MOORE; DAVID W. DENNING

1998-01-01

394

Aminopeptidases from Aspergillus niger  

Microsoft Academic Search

Aspergillusis a filamentous fungus that can grow in many environments, on several substrates at different conditions. In the soil,Aspergilli<\\/span>recycle nutrients by the degradation of plant material. In particular,Aspergilli<\\/span>are known for their capability to spoil plant materials like grains and fruits. In the industryAspergilli<\\/span>are often being used as hosts for the production of both homologous andheterologous<\\/span>(foodgrade<\\/span>)

Wijk van D

2004-01-01

395

Site-Directed Mutagenesis Improves the Thermostability and Catalytic Efficiency of Aspergillus niger N25 Phytase Mutated by I44E and T252R.  

PubMed

Aspergillus niger phytase (PhyA) has been used as a feed supplement to improve the bioavailability of phytate phosphorus to swine and poultry. However, it is unable to maintain its stability due to high temperature during the feed pelleting process. In this study, we performed site-directed mutagenesis in the Aspergillus niger N25 phyA (m) gene at residue 44I and 252 T, and they were replaced by glutamic acid and arginine. Single-site mutants I44E-PhyA and T252R-PhyA, as well as double-site mutant I44E/T252R-PhyA, were constructed to improve the thermostability of PhyA through hydrogen bondings and ionic interactions. The three mutant enzymes all showed more than 20 % improvement in thermostability compared to the wild-type enzyme after being heated at 80 °C for 10 min. Their melting temperatures (T m) were increased by 1, 1, and 1.2 °C, respectively. The k m values of I44E-PhyA, T252R-PhyA, and I44E/T252R-PhyA for sodium phytate were 78, 44, and 79 % lower (P <0.05) than that of the wild-type enzyme. Overall catalytic efficiency (k cat/k m) of I44E-PhyA, T252R-PhyA, and I44E/T252R-PhyA was improved by 310, 155, and 84 % (P <0.05) than that of the wild type, respectively. The catalytic efficiency did not seem to be negatively affected by the improvement in thermostability. PMID:23907680

Liao, Yan; Li, Chun-Mei; Chen, Hui; Wu, Qi; Shan, Zhi; Han, Xue-Yi

2013-08-02

396

Role of different additives and metallic micro minerals on the enhanced citric acid production by Aspergillus niger MNNG-115 using different carbohydrate materials.  

PubMed

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

Ali, Sikander; Haq, Ikram-ul

2005-01-01

397

Dynamic Changes in Xylanases and ?-1,4-Endoglucanases Secreted by Aspergillus niger An-76 in Response to Hydrolysates of Lignocellulose Polysaccharide.  

PubMed

Aspergillus niger is an effective secretor of glycoside hydrolases that facilitate the saprophytic lifestyle of the fungus by degrading plant cell wall polysaccharides. In the present study, a series of dynamic zymography assays were applied to quantify the secreted glycoside hydrolases of A. niger cultured in media containing different carbon sources. Differences in the diversity and concentrations of polysaccharide hydrolysates dynamically regulated the secretion of glycoside hydrolases. The secretion of ?-1,4-endoglucanase isozymes was observed to lag at least 24 h behind, rather than coincide with, the secretion of xylanase isozymes. Low concentrations of xylose could induce many endoxylanases (such as Xyn1/XynA, Xyn2, and Xyn3/XynB). High concentrations of xylose could sustain the induction of Xyn2 and Xyn3/XynB but repress Xyn1/XynA (GH10 endoxylanase), which has a broad substrate specificity, and also triggers the low-level secretion of Egl3/EglA, which also has a broad substrate specificity. Mixed polysaccharide hydrolysates sustained the induction of Egl1, whereas the other ?-1,4-endoglucanases were sustainably induced by the specific polysaccharide hydrolysates released during the hydrolysis process (such as Egl2 and Egl4). These results indicate that the secretion of glycoside hydrolases may be specifically regulated by the production of polysaccharide hydrolysates released during the process of biomass degradation. PMID:23900618

Xing, Sheng; Li, Guoli; Sun, Xulu; Ma, Su; Chen, Guanjun; Wang, Lushan; Gao, Peiji

2013-07-31

398

A spontaneous change in the intracellular cyclic AMP level in Aspergillus niger is influenced by the sucrose concentration in the medium and by light.  

PubMed Central

A spontaneous rise in intracellular cyclic AMP (cAMP) levels was observed in the early stages of Aspergillus niger growth under conditions yielding large amounts of citric acid. The amount of cAMP formed was found to depend on the initial concentration of sucrose in the medium. Under higher-sucrose conditions, the cAMP peak appeared earlier and was higher, while in lower-sucrose media a flattened peak was observed later in fermentation. Since in media with higher concentrations of sucrose intracellular citric acid starts to accumulate earlier and more rapidly, cAMP synthesis may be triggered by intracellular acidification, which is caused by the dissociation of citric acid. No spontaneous increase in cAMP concentrations could be detected when the cells were grown in continuously illuminated cultures, suggesting that A. niger phosphodiesterase (PDE) is photoregulated. More evidence for the activation of PDE by light was obtained from morphological studies under light and dark conditions in the presence of cAMP or N6,O2'-dibutyryl cAMP, and this idea was additionally supported by experiments in which PDE inhibitors were tested.

Gradisnik-Grapulin, M; Legisa, M

1997-01-01

399

Efficacy of the application of a coating composed of chitosan and Origanum vulgare L. essential oil to control Rhizopus stolonifer and Aspergillus niger in grapes (Vitis labrusca L.).  

PubMed

This study evaluated the efficacy of the combined application of chitosan (CHI) and Origanum vulgare L. essential oil (OV) in the inhibition of Rhizopus stolonifer URM 3728 and Aspergillus niger URM 5842 on laboratory media and on grapes (Vitis labrusca L.) and its influence on the physical, physicochemical and sensory characteristics of the fruits during storage (25 °C, 12 days and 12 °C, 24 days). The application of mixtures of different CHI and OV concentrations (Minimum Inhibitory Concentration - MIC, 1/2 MIC and 1/4 MIC) inhibited the mycelial growth of the test fungi. The application of CHI and OV at sub-inhibitory concentrations (CHI 1/2 MIC + OV 1/4 MIC; CHI 1/2 MIC + OV 1/2 MIC) inhibited spore germination and caused morphological changes in fungal spores and mycelia, in addition to inhibiting the growth of the assayed fungi strains in artificially infected grapes as well as the autochthonous mycoflora of grapes stored at both room and cold temperature. In general, the application of a coating composed of CHI and OV at sub-inhibitory concentrations preserved the quality of grapes as measured by their physical and physicochemical attributes, while some of their sensory attributes improved throughout the assessed storage time. These results demonstrate the potential of the combination of CHI and OV at sub-inhibitory concentrations to control post-harvest pathogenic fungi in fruits, in particular, R. stolonifer and A. niger in grapes. PMID:22986200

dos Santos, Nereide Serafim Timóteo; Athayde Aguiar, Ana Júlia Alves; de Oliveira, Carlos Eduardo Vasconcelos; Veríssimo de Sales, Camila; de Melo E Silva, Silvanda; Sousa da Silva, Rosana; Stamford, Thayza Christina Montenegro; de Souza, Evandro Leite

2012-08-07

400

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...

401

Construction of Engineered Bifunctional Enzymes and Their Overproduction in Aspergillus niger for Improved Enzymatic Tools To Degrade Agricultural By-Products  

PubMed Central

Two chimeric enzymes, FLX and FLXLC, were designed and successfully overproduced in Aspergillus niger. FLX construct is composed of the sequences encoding the feruloyl esterase A (FAEA) fused to the endoxylanase B (XYNB) of A. niger. A C-terminal carbohydrate-binding module (CBM family 1) was grafted to FLX, generating the second hybrid enzyme, FLXLC. Between each partner, a hyperglycosylated linker was included to stabilize the constructs. Hybrid proteins were purified to homogeneity, and molecular masses were estimated to be 72 and 97 kDa for FLX and FLXLC, respectively. Integrity of hybrid enzymes was checked by immunodetection that showed a single form by using antibodies raised against FAEA and polyhistidine tag. Physicochemical properties of each catalytic module of the bifunctional enzymes corresponded to those of the free enzymes. In addition, we verified that FLXLC exhibited an affinity for microcrystalline cellulose (Avicel) with binding parameters corresponding to a Kd of 9.9 × 10?8 M for the dissociation constant and 0.98 ?mol/g Avicel for the binding capacity. Both bifunctional enzymes were investigated for their capacity to release ferulic acid from natural substrates: corn and wheat brans. Compared to free enzymes FAEA and XYNB, a higher synergistic effect was obtained by using FLX and FLXLC for both substrates. Moreover, the release of ferulic acid from corn bran was increased by using FLXLC rather than FLX. This result confirms a positive role of the CBM. In conclusion, these results demonstrated that the fusion of naturally free cell wall hydrolases and an A. niger-derived CBM onto bifunctional enzymes enables the increase of the synergistic effect on the degradation of complex substrates.

Levasseur, Anthony; Navarro, David; Punt, Peter J.; Belaich, Jean-Pierre; Asther, Marcel; Record, Eric

2005-01-01

402

Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil  

PubMed Central

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.

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-01-01

403

Biodegradation of Low-Density Polyethylene (LDPE) by Mixed Culture of Lysinibacillus xylanilyticus and Aspergillus niger in Soil.  

PubMed

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

Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

2013-09-23

404

Co?production of aflatoxins and cyclopiazonic acid in isolates of Aspergillus flavus  

Microsoft Academic Search

The distribution of total aflatoxin (AFT) and cyclopiazonic acid (CPA) between conidia and mycelial matrix was studied in five isolates of Aspergillus flavus Link cultured on maize grain for 20 days at 30°C. Total aflatoxin and CPA production differed between the isolates with Aspergillus flavus F2R4FP 1–5 producing the most AFT (conidia—0.245 ?g\\/g; mycelial matrix—83 ?g\\/g) and CPA (conidia—0.091 ?g\\/g;

N. Gqaleni; J. E. Smith; J. Lacey

1996-01-01

405

Visual expression analysis of the responses of the alternative oxidase gene ( aox1) to heat shock, oxidative, and osmotic stresses in conidia of citric acid-producing Aspergillus niger  

Microsoft Academic Search

The citric acid-producing filamentous fungus Aspergillus niger WU-2223L shows cyanide-insensitive respiration catalyzed by alternative oxidase in addition to the cytochrome pathway. Sequence analysis of the 5’ flanking region of the alternative oxidase gene (aox1) revealed a potential heat shock element (HSE) and a stress response element (STRE). We have previously confirmed aox1 expression in conidia. In this study, to confirm

Yuki Honda; Takasumi Hattori; Kohtaro Kirimura

406

Expression, Purification, and Characterization of the Recombinant Calcium-Binding Equine Lysozyme Secreted by the Filamentous Fungus Aspergillus niger:Comparisons with the Production of Hen and Human Lysozymes  

Microsoft Academic Search

Equine lysozyme (EqL) has been expressed from a synthetic gene and secreted from a heterologous host, the filamentous fungusAspergillus niger.By including 100 mM Ca2+in the growth medium, secreted yields of more than 50 mg\\/liter could be achieved using polyvinylpyrrolidone (PVP) complete medium. In a soya medium yields of up to 150 mg\\/liter were achieved. The production of recombinant human lysozyme

Andrew Spencer; Ludmilla A. Morozov-Roche; Wim Noppe; Donald A. MacKenzie; David J. Jeenes; Marcel Joniau; Christopher M. Dobson; David B. Archer

1999-01-01

407

[Isolation of Aspergillus section Nigri strains in yerba mate in Posadas (Misiones, Argentina) and evaluation of their ochratoxigenic potential].  

PubMed

The objectives of the present work were to investigate the isolation frequency of genus Aspergillus in canchada yerba mate (YMCH) and elaborated yerba mate (YME) (Ilex paraguariensis) and the proportion of section Nigri isolates, as well as to determine ochratoxin A production by Aspergillus species section Nigri. Three hundred twenty eight Aspergillus strains from 20 samples of YMCH and 1306 Aspergillus strains from 36 samples of YME were isolated; of the total, 279 from the first group of strains and 1215 from the latter group, belonged to section Nigri. For the detection of ochratoxin A production, the strains were cultivated on Czapeck yeast extract agar and the toxin was detected by thin layer chromatography under UV light. Uniserate species predominance was observed in the 1494 strains of Aspergillus section Nigri obtained (Aspergillus japonicus var. japonicus and Aspergillus japonicus var. aculeatus), whereas none of the strains analysed showed ochratoxin A production in vitro at the detection level of the methodology employed. PMID:23876265

Castrillo, María L; Horianski, Marta A; Jerke, Gladis

408

Biosynthesis of citric acid in relation to the activity of selected enzymes of the Krebs cycle in Aspergillus niger mycelium  

Microsoft Academic Search

Summary  The activities of ACH1, NAD-ICDH, NADP-ICDH and CS were determined in cell extracts of high and low citric acid-producing strains of A. niger, cultivated on molasses medium by the surface or submerged method. A high differentiation in the activities of the enzymes\\u000a studied was found to occur at various accumulation stages of citric acid and during its decomposition by moulds.

J. Szczodrak; Maria Curie-Sk

1981-01-01

409

d-Xylose Concentration-Dependent Hydrolase Expression Profiles and the Function of CreA and XlnR in Aspergillus niger  

PubMed Central

Aspergillus niger is an important organism for the production of industrial enzymes such as hemicellulases and pectinases. The xylan-backbone monomer, d-xylose, is an inducing substance for the coordinate expression of a large number of polysaccharide-degrading enzymes. In this study, the responses of 22 genes to low (1 mM) and high (50 mM) d-xylose concentrations were investigated. These 22 genes encode enzymes that function as xylan backbone-degrading enzymes, accessory enzymes, cellulose-degrading enzymes, or enzymes involved in the pentose catabolic pathway in A. niger. Notably, genes encoding enzymes that have a similar function (e.g., xylan backbone degradation) respond in a similar manner to different concentrations of d-xylose. Although low d-xylose concentrations provoke the greatest change in transcript levels, in particular, for hemicellulase-encoding genes, transcript formation in the presence of high concentrations of d-xylose was also observed. Interestingly, a high d-xylose concentration is favorable for certain groups of genes. Furthermore, the repressing influence of CreA on the transcription and transcript levels of a subset of these genes was observed regardless of whether a low or high concentration of d-xylose was used. Interestingly, the decrease in transcript levels of certain genes on high d-xylose concentrations is not reflected by the transcript level of their activator, XlnR. Regardless of the d-xylose concentration applied and whether CreA was functional, xlnR was constitutively expressed at a low level.

Mach-Aigner, Astrid R.; Omony, Jimmy; Jovanovic, Birgit; van Boxtel, Anton J. B.

2012-01-01

410

Remediation of arsenic in soil by Aspergillus nidulans isolated from an arsenic?contaminated site  

Microsoft Academic Search

High concentrations of heavy metals, such as arsenic, in soils have potential long?term environmental and health consequences due to their persistence in the environment and their associated toxicity to biological organisms. Aspergillus nidulans isolated from arsenic?contaminated soil has the potential to remove arsenic from soil. The isolated resistant strain showed resistance up to 500 ppm and the mean weight was

S. Maheswari; A. G. Murugesan

2009-01-01

411

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...

412

COMPARISON OF TOXIGENIC AND ATOXIGENIC ISOLATES OF ASPERGILLUS FLAVUS USING DNA AMPLIFICATION FINGERPRINTING TECHNIQUES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aspergillus flavus is a filamentous fungus that produces mycotoxins in many food and feed crops, such as maize (Zea mays L.). Isolates were analyzed for toxin production by nucleic acid profiles in an attempt to differentiate toxigenic from atoxigenic isolates. A total of 41 toxigenic and 34 atox...

413

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), ...

414

Genetic diversity within Aspergillus flavus strains isolated from peanut-cropped soils in Argentina  

Microsoft Academic Search

The genetic diversity of Aspergillus flavus populations isolated from the peanut-cropped soils in the peanut-growing region at Cordoba Province was evaluated by analysis of vegetative compatibility group (VCG). VCGs were determined through complementation assays between nitrate-nonutilizing (NNO) mutants. Fifty-six VCGs were identified from 100 isolates. Twenty-five VCGs contained two or more isolates and 31 VCGs contained only a single isolate.

G. G. Barros; A. M. Torres; M. I. Rodriguez; S. N. Chulze

2006-01-01

415

Ochratoxigenic Aspergillus species on grapes from Chilean vineyards and Aspergillus threshold levels on grapes.  

PubMed

This study reports the incidence of ochratoxigenic strains of Aspergillus on Chilean grapes (Vitis vinifera) and wineries, and production of OTA levels in wines with grapes having different levels of contamination with OTA-producing Aspergillus carbonarius was studied. A. carbonarius, A. niger, A. niveus, A. paradoxus, A. versicolor, A. wentii, and A. westerdijkiae were identified on apparently healthy clusters of red and white grape cultivars. However, A. carbonarius and A. niger were the most frequently identified species, more abundant on red than white grape cultivars. Aspergillus spp. populations increased between veraison and harvest, but the isolation frequencies were relatively low over the entire growing season. At the winery, A. carbonarius, A. niger and A. westerdijkiae were occasionally found in the air, exclusively during winemaking. OTA-producing strains were only found among isolates of A. carbonarius, A. niger, A. wenti, and A. westerdijkiae, producing 2 to 17 microg/L of OTA in liquid medium; however, A. westerdijkiae produced the highest OTA concentration in vitro. Red wines elaborated with 0.5% of grapes infected with an OTA-producing strain of A. carbonarius (Aspuc-SB36) exceeded the 2 microg/L of OTA tolerance established for wines by the European Community. Therefore, a threshold below 0.5% infected berries is proposed for red wines. ELISA tests proved to be useful for detecting OTA in broth culture as in wine samples. PMID:19464066

Díaz, Gonzalo A; Torres, René; Vega, Mario; Latorre, Bernardo A

2009-04-24

416

Digital gene expression analysis of mature seeds of transgenic maize overexpressing Aspergillus niger phyA2 and its non-transgenic counterpart.  

PubMed

The next generation sequencing technologies have been recently used for transcriptome analysis in many organisms because of the decreased sequencing cost and increased sequence output. In this study, we used digital gene expression (DGE) technique to compare the transcriptomic changes in mature seeds between transgenic maize overexpressing Aspergillus niger phyA2 and its non-transgenic counterpart. Deep sequencing of DGE libraries of the transgenic and its non-transgenic counterpart seeds generated 3,783,500 and 3,790,500 reads of 21-nucleotide, respectively, with frequencies spanning over four orders of magnitude. In transgenic maize, 53.97% of the unambiguous signature tags were mapped to the maize B73 reference genome, and 46.47% of genes were detected by at least two reads; in non-transgenic maize, the corresponding numbers were 51.38% and 47.39%. Compared with non-transgenic counterpart, about 12% of detected genes were differentially expressed in the transcriptome of transgenic maize seeds. Among these differentially expressed genes, there were 23 transcription factors in 14 families and no allergen genes. Pathway enrichment analysis revealed that 21 pathways were significantly affected by the transgenic event, in which the pathway involved in protein processing in endoplasmic reticulum was the most significantly affected. Results from this study indicated that both intended and unintended transcriptomic changes occurred in the transgenic maize, thus emphasizing the importance of transcriptome profiling in risk assessment of transgenic events. PMID:23836108

Rao, Jun; Yang, Litao; Wang, Congmao; Zhang, Dabing; Shi, Jianxin

2013-04-01

417

Arrest of oogenesis in the bug Rhodnius prolixus challenged with the fungus Aspergillus niger is mediated by immune response-derived PGE2.  

PubMed

In this work we characterized the immune response of the insect Rhodnius prolixus to a direct injection into the hemocoel of the non-entomopathogenic fungus Aspergillus niger, and evaluated its consequences on host oogenesis. These animals were able to respond by mounting effective cellular and humoral responses to this fungus; these responses were shown, however, to have reproductive fitness costs, as the number of eggs laid per female was significantly reduced. The disturbance of egg formation during infectious process correlated with an elevation in the titer of hemolymph prostaglandin E2 48 h post-challenge. Administration of Zymosan A as an immunogenic non-infectious challenge produced similar effects on phenoloxidase and prophenoloxidase activities, oocyte development and prostaglandin E2 titer, precluding the hypothesis of an effect mediated by fungal metabolites in animals challenged with fungus. Ovaries at 48 h post-challenge showed absence of vitellogenic ovarian follicles, and the in vivo administration of prostaglandin E2 or its receptor agonist misoprostol, partially reproduced this phenotype. Together these data led us to hypothesize that immune-derived prostaglandin E2 raised from the insect response to the fungal challenge is involved in disturbing follicle development, contributing to a reduction in host reproductive output and acting as a host-derived adaptive effector to infection. PMID:19059412

Medeiros, Marcelo Neves de; Belmonte, Rodrigo; Soares, Bruno César C; Medeiros, Luciano Neves de; Canetti, Cláudio; Freire-de-Lima, Celio G; Maya-Monteiro, Clarissa Menezes; Bozza, Patrícia Torres; Almeida, Igor C; Masuda, Hatisaburo; Kurtenbach, Eleonora; Machado, Ednildo A

2008-12-25

418

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

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 (R (2)) 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

Dinarvand, Mojdeh; Rezaee, Malahat; Masomian, Malihe; Jazayeri, Seyed Davoud; Zareian, Mohsen; Abbasi, Sahar; Ariff, Arbakariya B

2013-09-15

419

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

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.

Dinarvand, Mojdeh; Rezaee, Malahat; Masomian, Malihe; Jazayeri, Seyed Davoud; Zareian, Mohsen; Abbasi, Sahar; Ariff, Arbakariya B.

2013-01-01

420

Pathogenicity of an isolate of aspergillus fla vus in chickens  

Microsoft Academic Search

Cockerels aged 8 days were each given intraperitoneally a 1 ml suspension of Aspergillus flavus grown on Sabouraud's dextrose agar containing 10 colony forming units per ml. No clinical signs were observed but mortality was 37.5%. Liver and kidney were enlarged at necropsy. Granulomatous nodules were found in the serosa and lung parenchyma up to day 16 post?infection but by

J. O. A. Okoye; C. N. Okeke

1986-01-01

421

Aspergillus sp. isolated in critically ill patients with extracorporeal membrane oxygenation support.  

PubMed

Abstract This study reports Aspergillus isolation in critically ill patients who underwent extracorporeal membrane oxygenation (ECMO) and highlights the difficulty in establishing a diagnosis of aspergillosis in this population. The diagnosis of Aspergillus infection or colonization was retrospectively performed using the proposed modified criteria of the European Organization for Research and Treatment of Cancer and the Mycoses Study Group (EORTC/MSG) adapted to critically ill patients. Between 2005 and 2011, 11 of 151 patients (7.2%) who underwent ECMO had Aspergillus sp. isolates, 10 in a pulmonary sample and 1 in a mediastinal wound sample. Five patients did not have any classical risk factors for aspergillosis. One patient had a proven invasive pulmonary aspergillosis (IPA), 2 had a putative IPA, and 1 patient had a possible Aspergillus mediastinitis, whilst in 7 patients this was considered colonization. However, the clinical relevance of Aspergillus isolation was based on an algorithm not validated in patients undergoing ECMO. Our data support the need to implement non-invasive diagnostic procedures for aspergillosis in this population. PMID:23746344

Aubron, Cecile; Pilcher, David; Leong, Tim; Cooper, D James; Scheinkestel, Carlos; Pellegrino, Vince; Cheng, Allen C

2013-06-09

422

Mapping the structural requirements of inducers and substrates for decarboxylation of weak acid preservatives by the food spoilage mould Aspergillus niger.  

PubMed

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 6.5Å and 9Å. 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

Stratford, Malcolm; Plumridge, Andrew; Pleasants, Mike W; Novodvorska, Michaela; Baker-Glenn, Charles A G; Pattenden, Gerald; Archer, David B

2012-06-15

423

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...

424

Non-specificity of nutritional substrate for ochratoxin A production by isolates of Aspergillus ochraceus  

Microsoft Academic Search

Aspergillus ochraceus is an important contaminant of diverse substrates, such as cereals, coffee, grapes and derivates. This fungus produce a nephrotoxic metabolite, ochratoxin A (OTA), whose presence on food and feeds may be an important risk for animal and human health.The aim of this work was to evaluate the significance of the origin of A. ochraceus isolates on their OTA

E. Pardo; V. Sanchis; A. J. Ramos; S. Marín

2006-01-01