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1

Isolation and characterization of alpha-glucosidase from Aspergillus niger.  

PubMed

alpha-Glucosidase is an enzyme widely used in biochemical analytical methods. Aspergillus niger was selected as a potential source for its production. Conditions for glucosidase production were optimized and the enzyme was isolated from the culture supernatant by dialysis and anion-exchange chromatography. The activity of the enzyme was determined by maltose hydrolysis to glucose, which was determined using a glucose-specific electrode or by high-performance liquid chromatography. The isolated enzyme was further characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis, substrate specificity and fast protein liquid chromatography. The Michaelis constant, optimal temperature and stability of the enzyme preparation were determined. PMID:1639895

Brízová, K; Králová, B; Demnerová, K; Vins, I

1992-02-28

2

Thermal Characterization of Purified Glucose Oxidase from A Newly Isolated Aspergillus Niger UAF-1  

PubMed Central

An intracellular glucose oxidase was isolated from the mycelium extract of a locally isolated strain of Aspergillus niger UAF-1. The enzyme was purified to a yield of 28.43% and specific activity of 135 U mg?1 through ammonium sulfate precipitation, anion exchange and gel filtration chromatography. The enzyme showed high affinity for D-glucose with a Km value of 2.56 mM. The enzyme exhibited optimum catalytic activity at pH 5.5. Temperature optimum for glucose oxidase, catalyzed D-glucose oxidation was 40°C. The enzyme showed a high thermostability having a half-life 30 min, enthalpy of denaturation 99.66 kJ mol?1 and free energy of denaturation 103.63 kJ mol?1. These characteristics suggest the use of glucose oxidase from Aspergillus niger UAF-1 as an analytical reagent and in the design of biosensors for clinical, biochemical and diagnostic assays.

Anjum Zia, Muhammad; Khalil-ur-Rahman; K. Saeed, Muhammad; Andaleeb, Fozia; I. Rajoka, Muhammad; A. Sheikh, Munir; A. Khan, Iftikhar; I. Khan, Azeem

2007-01-01

3

[Isolation and characterization of mutants of Aspergillus niger deficient in extracellular proteases].  

PubMed

Several mutants of Aspergillus niger 3.795, deficient in extracellular protease expression, have been isolated and characterized biochemically after in vitro UV-mutagenesis of conidiospores and selected by halo-screening on the gelatin/casein plate and skim milk plate. Extracellular proteolytic activities of 3.795-1-23 and 3.795-1-30 are 5.4% and 8.4% of the parental strain and these strains may be used as the host for efficient expression of foreign proteins. PMID:12548962

Hong, B; Zhang, Y; Li, Y

2000-08-01

4

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

5

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

PubMed

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(5+), Cd(2+), Cu(2+)) at final concentrations of 25 and 50 mg/L and H(2)O(2) (20 or 40 mM) mostly stimulated production of catalases only in isolates from mines surroundings, and H(2)O(2) and Hg(2+) caused the disappearance of the smallest catalase I. Isolates exhibited a higher tolerance of the toxic effects of heavy metals and H(2)O(2), as monitored by growth, than did the strain from the culture collection. PMID:15902463

Bucková, Maria; Godocíková, Jana; Simonovicová, Alexandra; Polek, Bystrík

2005-04-01

6

Purification and biochemical characterisation of glucoamylase from a newly isolated Aspergillus niger: Relation to starch processing.  

PubMed

Herein, we investigate a glucoamylase from newly isolated Aspergillus niger. The enzyme was purified, using fractionation, followed by anion-exchange chromatography and then characterised. The molecular mass of the enzyme was estimated to be ?62,000Da, using SDS-PAGE and 57151Da, based on mass spectrometry results. The pI of the protein, and optimum pH/temperature of enzyme activity were 4.4, 5 and 70°C, respectively and the kinetic parameters (Km, Vmax and kcat) were determined to be 0.33 (mgml(-1)), 0.095 (U?g(-1)min(-1)) and 158.3 (s(-1)) for soluble starch, respectively. The glucoamylase nature of the enzyme was also confirmed using TLC and a specific substrate. Metal ions Fe(3+), Al(3+) and Hg(2+) had the highest inhibitory effect, while Ag(2)(+), Ca(2+), Zn(2+), Mg(2+) and Cd(2+) and EDTA showed no significant effect on the enzyme activity. In addition, thermal stability of the enzyme increased in the presence of starch and calcium ion. Based on the results, the purified glucoamylase appeared to be a newly isolated enzyme. PMID:24837950

Bagheri, Ahmad; Khodarahmi, Reza; Mostafaie, Ali

2014-10-15

7

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

Microsoft Academic Search

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

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

2007-01-01

8

Production and characterization of alpha-amylase from Aspergillus niger JGI 24 isolated in Bangalore.  

PubMed

Five fungal isolates were screened for the production of alpha-amylase using both solid-state and submerged fermentations. The best amylase producer among them, Aspergillus niger JGI 24, was selected for enzyme production by solid-state fermentation (SSF) on wheat bran. Different carbon and nitrogen supplements were used to enhance enzyme production and maximum amount of enzyme was obtained when SSF was carried out with soluble starch and beef extract (1% each) as supplements. Further attempts to enhance enzyme production by UV induced mutagenesis were carried out. Survival rate decreased with increase in duration of UV exposure. Partial purification of the enzyme using ammonium sulphate fractionation resulted in 1.49 fold increase in the enzyme activity. The enzyme showed a molecular weight of 43 kDa by SDS-PAGE. Metal ions Ca2+ and Co2+ increased the enzyme activity. The enzyme was optimally active at 30 degrees C and pH 9.5. PMID:19469283

Varalakshmi, K N; Kumudini, B S; Nandini, B N; Solomon, J; Suhas, R; Mahesh, B; Kavitha, A P

2009-01-01

9

New dimeric naphthopyrones from Aspergillus niger.  

PubMed

Three new dimeric naphthopyrones, asperpyrones A (1), B (2), and C (3), together with two known compounds, fonsecinone A (4) and aurasperone A (5), have been isolated from okara that was fermented with Aspergillus niger JV-33-48. Compounds 1, 4, and 5 showed inhibitory activity on Taq DNA polymerase. PMID:12542363

Akiyama, Kohki; Teraguchi, Seigo; Hamasaki, Yukiko; Mori, Mika; Tatsumi, Kunihiko; Ohnishi, Kenji; Hayashi, Hideo

2003-01-01

10

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

2012-12-01

11

Utilization of ram horn peptone in the production of glucose oxidase by a local isolate Aspergillus niger OC-3.  

PubMed

Glucose oxidase (GO) is an enzyme that is used in many fields. In this study, ram horn peptone (RHP) was utilized as the nitrogen source and compared with other nitrogen sources in the production of GO by Aspergillus niger. To obtain higher GO activity, 14 A. niger strains were isolated from soil samples around Erzurum, Turkey. Among these strains, the isolate that was named A. niger OC-3 achieved the highest GO production. The production of GO was carried out in 100 mL scaled batch culture. The fermentation conditions such as initial pH, temperature, agitation speed, and time were investigated in order to improve GO production. The results showed that the cultivation conditions would significantly affect the formation of GO, and the utilization of the RHP achieved the highest enzyme production (48.6 U/mL) if compared to other nitrogen sources. On the other hand, the maximum biomass was obtained by using the fish peptone (7.2 g/L), while RHP yielded 6.4 g/L. These results suggest that RHP from waste ram horns could effectively be used in the production of GO by A. niger OC-3. PMID:21229465

Canli, Ozden; Kurbanoglu, Esabi Basaran

2011-01-01

12

Aspergillus niger contains the cryptic phylogenetic species A. awamori.  

PubMed

Aspergillus section Nigri is an important group of species for food and medical mycology, and biotechnology. The Aspergillus niger 'aggregate' represents its most complicated taxonomic subgroup containing eight morphologically indistinguishable taxa: A. niger, Aspergillus tubingensis, Aspergillus acidus, Aspergillus brasiliensis, Aspergillus costaricaensis, Aspergillus lacticoffeatus, Aspergillus piperis, and Aspergillus vadensis. Aspergillus awamori, first described by Nakazawa, has been compared taxonomically with other black aspergilli and recently it has been treated as a synonym of A. niger. Phylogenetic analyses of sequences generated from portions of three genes coding for the proteins ?-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1?) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species within this population, A. awamori. Morphological, physiological, ecological and chemical data overlap occurred between A. niger and the cryptic A. awamori, however the splitting of these two species was also supported by AFLP analysis of the full genome. Isolates in both phylospecies can produce the mycotoxins ochratoxin A and fumonisin B?, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-?-pyrones. In addition, sequence analysis of four putative A. awamori strains from Japan, used in the koji industrial fermentation, revealed that none of these strains belong to the A. awamori phylospecies. PMID:22036292

Perrone, Giancarlo; Stea, Gaetano; Epifani, Filomena; Varga, János; Frisvad, Jens C; Samson, Robert A

2011-11-01

13

Nitrile biotransformation by Aspergillus niger  

Microsoft Academic Search

A nitrile-converting enzyme activity was induced in Aspergillus niger K10 by 3-cyanopyridine. The whole cell biocatalyst was active at pH 3–11 and hydrolyzed the cyano group into acid and\\/or amide functions in benzonitrile as well as in its meta- and para-substituted derivatives, cyanopyridines, 2-phenylacetonitrile and thiophen-2-acetonitrile. Amides constituted a significant part of the total biotransformation products of 2- and 4-cyanopyridine,

Radka Šnajdrová; Veronika Kristová-Mylerová; Dominique Crestia; Konstantina Nikolaou; Marek Kuzma; Marielle Lemaire; Estelle Gallienne; Jean Bolte; Karel Bezouška; Vladim??r K?en; Ludmila Mart??nková

2004-01-01

14

Responses in the mycelial growth of Aspergillus niger isolates to arsenic contaminated environments and their resistance to exogenic metal stress.  

PubMed

Isolates of Aspergillus niger, selected from coal dust sediment of a mine containing As (400 mg/kg), pH 3.3-2.8, and from river sediment found near the mine (As, 363 mg/kg, Sb, 93 mg/kg), pH 5.2-4.8, growing on Czapek-Dox agar exhibited distinct responses in the mycelial growth in arsenic contaminated environments. The radial growth of the isolate from the coal dust in comparison to the control strain from an environment without pollution was reduced approximately to one-half. It formed black, very small compact colonies, with dense sporulation. The opposite, the strain from the river sediment, grew better in Czapek-Dox agar like the control. It formed larger colonies with dense centre and strong sporulation. Also, the culture from river sediment developed faster than the coal dust isolate and control strain. Differences were also recorded in size and thickness of conidia heads, phialide, metulae, and conidiophores. Both isolates from contaminated localities exhibited higher tolerance to exogenic toxic effects of As5+, Cd2+ and Cu2+ (5, 25 or 50 mg/l) than the control culture. Tolerance was monitored using the growth of biomass in liquid Czapek-Dox medium. We confirmed the morphological identification of our isolates to A. niger species with the PCR method. The results refer to complicated relations between biotic and abiotic effects that may directly affect the processes observed in the in situ environment. PMID:17647207

Bucková, Mária; Godocíková, Jana; Polek, Bystrík

2007-08-01

15

Optimization of the production of thermostable endo-beta-1,4 mannanases from a newly isolated Aspergillus niger gr and Aspergillus flavus gr.  

PubMed

The aim of this work was to establish optimal conditions for the maximum production of endo-beta-1,4 mannanases using cheaper sources. Eight thermotolerant fungal strains were isolated from garden soil and compost samples collected in and around the Gulbarga University campus, India. Two strains were selected based on their ability to produce considerable endo-beta-1,4 mannanases activity while growing in liquid medium at 37 degrees C with locust bean gum (LBG) as the only carbon source. They were identified as Aspergillus niger gr and Aspergillus flavus gr. The experiment to evaluate the effect of different carbon sources, nitrogen sources, temperatures and initial pH of the medium on maximal enzyme production was studied. Enzyme productivity was influenced by the type of polysaccharide used as the carbon source. Copra meal defatted with n-hexane showed to be a better substrate than LBG and guar gum for endo-beta-1,4 mannanases production by A. niger gr (40.011 U/ml), but for A. flavus gr (33.532 U/ml), the difference was not significant. Endo-beta-1,4 mannanases produced from A. niger gr and A. flavus gr have high optimum temperature (65 and 60 degrees C) and good thermostability in the absence of any stabilizers (maintaining 50% of residual activity for 8 and 6 h, respectively, at 60 degrees C) and are stable over in a wide pH range. These new strains offer an attractive alternative source of enzymes for the food and feed processing industries. PMID:18597050

Kote, Naganagouda V; Patil, Aravind Goud G; Mulimani, V H

2009-02-01

16

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

17

[Paramagnetic properties of the conidial pigments of Aspergillus niger and Penicillium notatum fungi isolated from the mesosphere].  

PubMed

The conidia of Aspergillus niger and Penicillium notatum detected in the upper atmospheric layers of the Earth (58--77 km) were found to contain stable paramagnetic centres (PMC) at concentrations of 0.2 X 10(18) and 1.6 X 10(18) per gram of dry biomass, respectively. Aspergillin, the black pigment of Asp. niger, was shown to have (0.1--0.6) X 10(18) PMC per gram of dry substance (depending on the fraction). Stable paramagnetism of the conidial pigments with respect to their active protecting action in vivo is discussed on the basis of these data. PMID:213700

Liakh, S P; Lysenko, S V

1978-01-01

18

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

19

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

PubMed Central

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

Gajera, H. P.; Vakharia, D. N.

2012-01-01

20

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

2010-05-01

21

Phytosterols elevation in bamboo shoot residue through laboratorial scale solid-state fermentation using isolated Aspergillus niger CTBU.  

PubMed

Aspergillus niger CTBU isolated from local decayed bamboo shoot residue was employed to solid-state fermentation (SSF) of bamboo shoot residue to elevate the content of phytosterols. Strain acclimatization was carried out under the fermentation condition using bamboo shoot as substrate for fermentation performance improvement. The optimal fermentation temperature and nitrogen level were investigated using acclimatized strain, and SSF was carried out in a 500-ml Erlenmeyer flask feeding 300-mg bamboo shoot residue chips under the optimal condition (33 °C and feeding 4 % urea), and 1,186 mg (100 g)(-1) of total phytosterol was attained after 5-day fermentation, in comparison, only 523 mg (100 g)(-1) of phytosterol was assayed in fresh shoots residue. HPLC analysis of the main composition of total phytosterols displays that the types of phytosterols and composition ratio of main sterols keep steady. This laboratorial scale SSF unit could be scaled up for raw phytosterols production from discarded bamboo shoot residue and could reduce its cost. PMID:24610040

Zheng, X X; Chen, R S; Shen, Y; Yin, Z Y

2014-04-01

22

Novel metabolites in phenanthrene and pyrene transformation by Aspergillus niger.  

PubMed Central

Aspergillus niger, isolated from hydrocarbon-contaminated soil, was examined for its potential to degrade phenanthrene and pyrene. Two novel metabolites, 1-methoxyphenanthrene and 1-methoxypyrene, were identified by conventional chemical techniques. Minor metabolites identified were 1- and 2-phenanthrol and 1-pyrenol. No 14CO2 evolution was observed in either [14C]phenanthrene or [14C]pyrene cultures.

Sack, U; Heinze, T M; Deck, J; Cerniglia, C E; Cazau, M C; Fritsche, W

1997-01-01

23

Response surface methodology for optimization of culture conditions for dye decolorization by a fungus, Aspergillus niger HM11 isolated from dye affected soil  

PubMed Central

Background and Objectives Discharge of wastewater from textile dyeing industries has been a problem in terms of pollution and treatment of these waters is a great task. Keeping this in mind, the aim of our current research is to study the effect of various bioprocess variables on decolorization of an azo dye, Congo red, by a fungal isolate, Aspergillus niger HM11. Materials and Methods Central composite design (CCD) and response surface methodology (RSM) have been applied to design experiments to evaluate the interactive effects of the operating variables: on the decolorization of Congo red. A total of 30 experiments were conducted in the present study and a regression coefficient between the variables was generated. Results The RSM indicated that pH 6.0, 150 rpm agitation, incubation time of 36 hrs and a glucose concentration of 1.0% were optimal for maximum decolorization of Congo red and the response indicated excellent evaluation of experimental data. Conclusion From this study, it is very obvious that the fungal isolate, Aspergillus niger HM11 can be used as a promising microbial strain for decolorization of textile dyeing effluent containing similar dyes.

Karthikeyan, K; Nanthakumar, K; Shanthi, K; Lakshmanaperumalsamy, P

2010-01-01

24

Galactosaminogalactan from cell walls of Aspergillus niger.  

PubMed Central

A new heteropolysaccharide has been isolated by alkaline extraction of hyphal walls of Aspergillus niger NRRL 326 grown in surface culture. Its composition by weight, as determined by paper and gas chromatography and colorimetric analyses, is 70% galactose, 20% galactosamine, 6% glucose, and 1% acetyl. Two independent experiments have been used to ascertain copolymer structure: permeation chromatography in 6 M guanidinium hydrochloride, with controlled-pore glass columns of two fractionation ranges, and nitrous acid deaminative cleavage of galactosaminogalactan followed by reduction of fragments with [3H]borohydride and gel filtration chromatography. One of the tritiated fragments is tentatively identified as the disaccharide derivative galactopyranosyl 2,5-anhydrotalitol, on the basis of chromatographic properties and by kinetics of its acid hydrolysis. Smith degradation, methylation, deamination, and optical rotation studies indicate that the galactosaminogalactan consists of a linear array of hexopyranosyl units joined almost exclusively by alpha-(1 leads to 4) linkages. Hexosaminyl moieties are distributed randomly along the chains, which have an average degree of polymerization of about 100. The possible significance of this macromolecule in hyphal structure is considered.

Bardalaye, P C; Nordin, J H

1976-01-01

25

Isolation and characterization of two specific regulatory Aspergillus niger mutants shows antagonistic regulation of arabinan and xylan metabolism.  

PubMed

This paper describes two Aspergillus niger mutants (araA and araB) specifically disturbed in the regulation of the arabinanase system in response to the presence of L-arabinose. Expression of the three known L-arabinose-induced arabinanolytic genes, abfA, abfB and abnA, was substantially decreased or absent in the araA and araB strains compared to the wild-type when incubated in the presence of L-arabinose or L-arabitol. In addition, the intracellular activities of L-arabitol dehydrogenase and L-arabinose reductase, involved in L-arabinose catabolism, were decreased in the araA and araB strains. Finally, the data show that the gene encoding D-xylulose kinase, xkiA, is also under control of the arabinanolytic regulatory system. L-Arabitol, most likely the true inducer of the arabinanolytic and L-arabinose catabolic genes, accumulated to a high intracellular concentration in the araA and araB mutants. This indicates that the decrease of expression of the arabinanolytic genes was not due to lack of inducer accumulation. Therefore, it is proposed that the araA and araB mutations are localized in positive-acting components of the regulatory system involved in the expression of the arabinanase-encoding genes and the genes encoding the L-arabinose catabolic pathway. PMID:12724380

de Groot, Marco J L; van de Vondervoort, Peter J I; de Vries, Ronald P; vanKuyk, Patricia A; Ruijter, George J G; Visser, Jaap

2003-05-01

26

Fingernail Onychomycosis Due to Aspergillus niger  

PubMed Central

Onychomycosis is usually caused by dermatophytes, but some species of nondermatophytic molds and yeasts are also associated with nail invasion. Aspergillus niger is a nondermatophytic mold which exists as an opportunistic filamentous fungus in all environments. Here, we report a case of onychomycosis caused by A. niger in a 66-year-old female. The patient presented with a black discoloration and a milky white base and onycholysis on the proximal portion of the right thumb nail. Direct microscopic examination of scrapings after potassium hydroxide (KOH) preparation revealed dichotomous septate hyphae. Repeated cultures on Sabouraud's dextrose agar (SDA) without cycloheximide produced the same black velvety colonies. No colony growth occurred on SDA with cycloheximide slants. Biseriate phialides covering the entire vesicle with radiate conidial heads were observed on the slide culture. The DNA sequence of the internal transcribed spacer region of the clinical sample was a 100% match to that of A. niger strain ATCC 16888 (GenBank accession number AY373852). A. niger was confirmed by KOH mount, colony identification, light microscopic morphology, and DNA sequence analysis. The patient was treated orally with 250 mg terbinafine daily and topical amorolfine 5% nail lacquer for 3 months. As a result, the patient was completely cured clinically and mycologically.

Kim, Dong Min; Ha, Gyoung Yim; Sohng, Seung Hyun

2012-01-01

27

Cloning and expression of a second Aspergillus niger pectin lyase gene ( pel A): Indications of a pectin lyase gene family in A. niger  

Microsoft Academic Search

Using the previously cloned Aspergillus niger N756 pectin lyase D gene as a probe, the corresponding pelD gene has been isolated from a genomic library of the loboratory strain A. niger N400. This gene encodes PLD, previously described as PLI, which is one of the two major pectin lyases isolated from the commeriial pectinase preparation Ultrazym®. Heterologous hybridization of the

J. A. M. Harmsen; M. A. Kusters-van Someren; J. Visser

1990-01-01

28

Identification and cloning of a second phytase gene (phyB) from Aspergillus niger (ficuum).  

PubMed

An Aspergillus niger (ficuum) genomic DNA lambda EMBL3 library was probed with a 354-bp DNA fragment obtained by polymerase chain reaction of A. niger DNA with oligonucleotides based on partial amino acid sequence of a pH 2.5 optimum acid phosphatase. A clone containing a 1605 bp segment (phyB) encoding the 479 amino acid enzyme was isolated and found to contain four exons. Global alignment revealed 23.5% homology to Aspergillus niger phytase (PhyA); four regions of extensive homology were identified. Some of these regions may contain catalytic sites for phosphatase function. PMID:7916610

Ehrlich, K C; Montalbano, B G; Mullaney, E J; Dischinger, H C; Ullah, A H

1993-08-31

29

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains  

PubMed Central

Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins: fumonisins and ochratoxins. In this study all available industrial and many non-industrial strains of A. niger (180 strains) as well as 228 strains from 17 related black Aspergillus species were examined for mycotoxin production. None of the related 17 species of black Aspergilli produced fumonisins. Fumonisins (B2, B4, and B6) were detected in 81% of A. niger, and ochratoxin A in 17%, while 10% of the strains produced both mycotoxins. Among the industrial strains the same ratios were 83%, 33% and 26% respectively. Some of the most frequently used strains in industry NRRL 337, 3112 and 3122 produced both toxins and several strains used for citric acid production were among the best producers of fumonisins in pure agar culture. Most strains used for other biotechnological processes also produced fumonisins. Strains optimized through random mutagenesis usually maintained their mycotoxin production capability. Toxigenic strains were also able to produce the toxins on media suggested for citric acid production with most of the toxins found in the biomass, thereby questioning the use of the remaining biomass as animal feed. In conclusion it is recommended to use strains of A. niger with inactive or inactivated gene clusters for fumonisins and ochratoxins, or to choose isolates for biotechnological uses in related non-toxigenic species such as A. tubingensis, A. brasiliensis, A vadensis or A. acidus, which neither produce fumonisins nor ochratoxins.

Frisvad, Jens C.; Larsen, Thomas O.; Thrane, Ulf; Meijer, Martin; Varga, Janos; Samson, Robert A.; Nielsen, Kristian F.

2011-01-01

30

Funalenone, a novel collagenase inhibitor produced by Aspergillus niger.  

PubMed

Funalenone, a phenalene compound that inhibits type I collagenase (MMP-1), was isolated from mycelium of Aspergillus niger FO-5904 by solvent extaction, ODS column chromatography, Sephadex LH-20 column chromatography and reversed phase HPLC. Funalenone inhibited 50% of type I collagenase activity at a concentration of 170 microM, but inhibited 18.3% and 38.7% against 72 kDa and 92 kDa type IV collagenase, respectively, at a concentration of 400 microM. PMID:10695672

Inokoshi, J; Shiomi, K; Masuma, R; Tanaka, H; Yamada, H; Omura, S

1999-12-01

31

Isolation, characterization, and molecular cloning of the cDNA encoding a novel phytase from Aspergillus niger 113 and high expression in Pichia pastoris.  

PubMed

Phytases catalyze the release of phosphate from phytic acid. Phytase-producing microorganisms were selected by culturing the soil extracts on agar plates containing phytic acid. Two hundred colonies that exhibited potential phytase activity were selected for further study. The colony showing the highest phytase activity was identified as Aspergillus niger and designated strain 113. The phytase gene from A. niger 113 (phyI1) was isolated, cloned, and characterized. The nucleotide and deduced amino acid sequence identity between phyI1 and phyA from NRRL3135 were 90% and 98%, respectively. The identity between phyI1 and phyA from SK-57 was 89% and 96%. A synthetic phytase gene, phyI1s, was synthesized by successive PCR and transformed into the yeast expression vector carrying a signal peptide that was designed and synthesized using P. pastoris biased codon. For the phytase expression and secretion, the construct was integrated into the genome of P. pastoris by homologous recombination. Over-expressing strains were selected and fermented. It was discovered that ~4.2 g phytase could be purified from one liter of culture fluid. The activity of the resulting phytase was 9.5 U/mg. Due to the heavy glycosylation, the expressed phytase varied in size (120, 95, 85, and 64 kDa), but could be deglycosylated to a homogeneous 64 kDa species. An enzymatic kinetics analysis showed that the phytase had two pH optima (pH 2.0 and pH 5.0) and an optimum temperature of 60 degrees C. PMID:15469708

Xiong, Ai-Sheng; Yao, Quan-Hong; Peng, Ri-He; Li, Xian; Fan, Hui-Qin; Guo, Mei-Jin; Zhang, Si-Liang

2004-05-31

32

Isolation and growth characterization of chlorate and/or bromate resistant mutants generated by spontaneous and induced foreword mutations at several gene loci in aspergillus niger  

PubMed Central

We aimed her mainly to evaluate the contribution of newly employed bromate selection system, in obtaining new Aspergillus niger nitrate/nitrite assimilation defective mutants, through Ultraviolet treatment (UV), 1, 2, 7, 8-Diepoxyoctane (DEO), phenols mixture (Phx)) and spontaneous treatments. The newly employed bromate selection system was able to specify only two putative novel mutant types designated brn (bromate resistant but chlorate sensitive (RS) strain, which may specify nitrite specific transporter) and cbrn mutants (bromate resistant and chlorate resistant strain, which may specify nitrate/nitrite bispecific system). The most relevant and innovative findings of this research work involve the isolation of the RR ( cbrn) mutants (a new type of nitrate assimilation defective mutants), that could be useful for studying the bispecific nitrate /nitrite transporter system. The majority of obtained bromate resistant mutants (93.3% of the total mutants obtained by all treatments) were of the brn type, whereas the remaining percentage (6.76%) was given to cbrn strains. The highest percentages of brn mutant strains (48% and 58.6% of the total RS strains) were obtained with UA after spontaneous and Phx treatment, whereas Trp has generated 29% and 42% of RS strains after UV and DEO treatments, respectively. The obtained ratios of cbrn mutants were higher (i.e. in the range of 8.4%-11.64% of the total bromate mutants) with chemical treatments, especially when U.A or Pro was serving as sole N-sources at 25şC rather than 37şC. A 69% mutants` yield of Aspergillus niger mutant strains representing nine gene loci ( niaD, cnx-6 loci , nrt and nirA) were selected on the bases of chlorate (600 mM) toxicity. All chlorate resistant mutants were completely sensitive to bromate (250 mM). The niaD mutants showed the highest percentage (73.97%) of chlorate resistant mutants obtained with all tested treatments. The UV treatment has generated the highest ratio (86.9%) of niaD mutants, whereas, the least (61%) was obtained with Phx treatment. The highest percentage of cnx mutants (32%) was obtained with Phx treatment. The DEO treatment as compared to other tested treatments was the best to use for obtaining the highest ratios of either nrt (13.8%) mutants or nirA (1.9%) mutants.

Kanan, Ghassan J. M.; Al-Najjar, Heyam E.

2010-01-01

33

Fumonisin and Ochratoxin Production in Industrial Aspergillus niger Strains  

Microsoft Academic Search

Aspergillus niger is perhaps the most important fungus used in biotechnology, and is also one of the most commonly encountered fungi contaminating foods and feedstuffs, and occurring in soil and indoor environments. Many of its industrial applications have been given GRAS status (generally regarded as safe). However, A. niger has the potential to produce two groups of potentially carcinogenic mycotoxins:

Jens C. Frisvad; Thomas O. Larsen; Ulf Thrane; Martin Meijer; Janos Varga; Robert A. Samson; Kristian F. Nielsen

2011-01-01

34

Isolation of four pepsin-like protease genes from Aspergillus niger and analysis of the effect of disruptions on heterologous laccase expression  

Microsoft Academic Search

Four new aspartic protease genes pepAa, pepAb, pepAc and pepAd from Aspergillus niger were identified using a comparative genomic approach. All four gene products have highly conserved attributes that are characteristic of aspartic proteases; however, each one has novel sequence features. The PEPAa protease appears to represent an ortholog of a pepsin-type aspartic protease previously identified from Talaromyces emersonii and

Yongchao Wang; Wei Xue; Andrew H. Sims; Chuntian Zhao; Aoquan Wang; Guomin Tang; Junchuan Qin; Huaming Wang

2008-01-01

35

Solubilization of hardly soluble iron and aluminum phosphates by the fungus Aspergillus niger in the soil  

Microsoft Academic Search

Some Brazilian soils present high contents of hardly soluble iron and aluminum phosphates and a high capacity for fixation\\u000a of soluble phosphates. This study evaluated the ability of the fungus Aspergillus niger F111 isolated from soil to solubilize Fe and Al phosphates. Iron, aluminum or calcium phosphate were added to soil samples and\\u000a inoculated with the A. niger F111. Sugar-cane

C. B. Barroso; E. Nahas

36

Invasive Aspergillus niger complex infections in a Belgian tertiary care hospital.  

PubMed

The incidence of invasive infections caused by the Aspergillus niger species complex was 0.043 cases/10 000 patient-days in a Belgian university hospital (2005-2011). Molecular typing was performed on six available A. niger complex isolates involved in invasive disease from 2010 to 2011, revealing A. tubingensis, which has higher triazole minimal inhibitory concentrations, in five out of six cases. PMID:24102876

Vermeulen, E; Maertens, J; Meersseman, P; Saegeman, V; Dupont, L; Lagrou, K

2014-05-01

37

Properties of Aspergillus niger citrate synthase and effects of citA overexpression on citric acid production 1 1 The EMBL accession number for the Aspergillus niger citA sequence reported in this paper is AJ243204  

Microsoft Academic Search

Using a combination of dye adsorption and affinity elution we purified Aspergillus niger citrate synthase to homogeneity using a single column and characterised the enzyme. An A. niger citrate synthase cDNA was isolated by immunological screening and used to clone the corresponding citA gene. The deduced amino acid sequence showed high similarity to other fungal citrate synthases. After processing upon

George J. G Ruijter; Henk Panneman; Ding-Bang Xu; Jaap Visser

2000-01-01

38

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

39

Solubilization of Morocco phosphorite by Aspergillus niger.  

PubMed

Phosphorus containing fertilizers have an important role in agriculture. Conventionally phosphate fertilizers are obtained by rock phosphate (RP) dissolution using mineral acids. Biotechnological methods can be a promising alternative in RP processing. The influence of Aspergillus niger strain, the composition of a nutritive medium, Morocco phosphorite (MP) concentration in the liquid medium, the time of bioconversion and the preliminary mechanical activation (PMA) of MP on the phosphorite microbial solubilization has been presented. The phosphorus concentration (as P2O5), citric acid production, glucose concentration and pH in the cultural medium were monitored. The phosphate concentration was expressed as water soluble - alpha1 (in the native cultural liquid), citrate soluble - alpha2 (after treating the biomass and remaining mineral mass with citric acid) and biomass available phosphorus - alpha3. Phosphate dissolution was not strongly correlated both with the citric acid production and the incubation period. When the fungi were grown without water soluble phosphorus compounds the MP solubilization had higher values. A maximum of 94.80% total P2O5 extraction was achieved. The PMA activity does not facilitate MP dissolution during the bioconversion. PMID:18468889

Bojinova, D; Velkova, R; Ivanova, R

2008-10-01

40

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

41

Amylase synthesis in Aspergillus flavus and Aspergillus niger grown on cassava peel  

Microsoft Academic Search

Summary Aspergillus flavus andAspergillus niger produce extracellular amylase into the culture medium when grown on basal medium containing 2% (w\\/v) soluble starch or cassava peel as the sole carbon source. On soluble tarch the highest amylase activities were 1.6 and 5.2 mg of starch hydrolyzed\\/min per mg protein forA. flavus andA. niger, respectively. When grown on cassava peel, the highest

Alhassan Sani; Francis A. Awe; Joseph A. Akinyanju

1992-01-01

42

Storability of onion bulbs contaminated by Aspergillus niger mold  

Microsoft Academic Search

In the course of pre- and postharvest epidemiological studies on bulbs contamination byAspergillus niger, two Sudanese onion cultivars were tested: ‘Saggai Red’ and ‘El-Hilo White’.A. niger spores, whether seedborne, soilborne or airborne, were avirulent to the healthy growing onion plants. The fungus heavily\\u000a contaminated the dead onion tissues, mainly the dead leaves followed by the dry scales, the dead roots

S. A. F. El-Nagerabi; A. H. M. Ahmed

2003-01-01

43

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

44

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

45

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

PubMed Central

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

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

2011-01-01

46

Production of citric acid with immobilized Aspergillus niger  

Microsoft Academic Search

The spores of Aspergillus niger were entrapped in calcium-alginate beads and precultivated in growth media with various amounts of nitrogen. During the following citric acid production in shaking cultures an optimum of acid formation and yield was observed after the precultivation with 100–200 mg\\/l NH4NO3. The productivity of the immobilized Aspergillus was found to be 1.5 times higher than in

H. Eikmeier; H. J. Rehm

1984-01-01

47

Expression profiling of pectinolytic genes from Aspergillus niger  

Microsoft Academic Search

The expression of 26 pectinolytic genes from Aspergillus niger was studied in a wild type strain and a CreA derepressed strain, under 16 different growth conditions, to obtain an expression profile for each gene. These expression profiles were then submitted to cluster analysis to identify subsets of genes with similar expression profiles. With the exception of the feruloyl esterase encoding

Ronald P. de Vries; Jenny Jansen; Guillermo Aguilar; Lucie Pa?enicová; Vivi Joosten; Florian Wülfert; Jacques A. E. Benen; Jaap Visser

2002-01-01

48

Pectinases of Aspergillus niger: A Molecular and Biochemical Characterisation  

Microsoft Academic Search

The major topics of this thesis are the microfilamentous fungus Aspergillus niger and the pectinases a group of extracellular enzymes. Many 'products' of this species hold the GRAS (Generally Regarded As Safe) status and thus pectinases find a broad range of applications in food, feed and beverage industries.Pectinases are enzymes which degrade pectin, a heteropolysaccharide found in the middle lamella

L. Parenicová

2000-01-01

49

Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus niger  

Microsoft Academic Search

The use of the fungus Aspergillus niger for the bioleaching of heavy metals from spent catalyst was investigated, with fluid catalytic cracking (FCC) catalyst as a model. Bioleaching was examined in batch cultures with the spent catalysts at various pulp densities (1–12%). Chemical leaching was also performed using mineral acids (sulphuric and nitric acids) and organic acids (citric, oxalic and

Khin Moh Moh Aung; Yen-Peng Ting

2005-01-01

50

Solubilization of rock phosphate by immobilized Aspergillus niger  

Microsoft Academic Search

Aspergillus niger, an acid-producing filamentous fungus, was immobilized on polyurethane foam. Various amounts of foam cubes and spore suspension were tested in order to obtain an efficient immobilization process. The best combination selected for further experiments was 0.2 g polyurethane foam and 3 ml spore suspension. Immobilized cells were reused, with higher levels of acid formation being maintained for longer

Nikolay Vassilev; Maria Vassileva; Rosario Azcon

1997-01-01

51

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

52

Incidence of fumonisin B(2) production by Aspergillus niger in Portuguese wine regions.  

PubMed

Fumonisin B(2) (FB(2)) was recently found to be produced by Aspergillus niger . When grape-derived products were subsequently analyzed, FB(2) contamination was found in raisins, must, and wine. This study evaluated 681 strains of black aspergilli species isolated from Portuguese wine grapes for FB(2) production when grown on Czapek yeast agar. FB(2) was not detected in Aspergillus carbonarius (n = 75) or Aspergillus ibericus (n = 9) strains, but it was detected in 176 (29%) of the strains belonging to A. niger aggregate (n = 597). The amount of FB(2) produced by these strains ranged from 0.003 to 6.0 mg/kg with a mean of 0.66 mg/kg. The Alentejo region had the lowest percentage (10%) of fumonisinogenic strains, whereas the Douro region had the highest percentage of fumonisinogenic strains (38%). Only 10 strains were found to produce FB(2) and ochratoxin A simultaneously. PMID:21668017

Abrunhosa, Luis; Calado, Thalita; Venancio, Armando

2011-07-13

53

Utility of Aspergillus niger citrate synthase promoter for heterologous expression.  

PubMed

Citrate synthase is a central player in the acidogenic metabolism of Aspergillus niger. The 5' upstream sequence (0.9kb DNA) of citrate synthase gene (citA) from A. niger NCIM 565 was analyzed and its promoter function demonstrated through the heterologous expression of two proteins. The cloned citrate synthase promoter (PcitA) sequence was able to express bar coding sequence thereby conferring phosphinothricin resistance. This sequence was further analyzed by systematic deletions to define an effective but compact functional promoter. The PcitA driven egfp expression showed that PcitA was active in all differentiation cell-stages of A. niger. EGFP expression was highest on non-repressible carbon sources like acetate and glycerol. Mycelial EGFP levels increased during acidogenic growth suggesting that PcitA is functional throughout this cultivation. A. niger PcitA is the first Krebs cycle gene promoter used to express heterologous proteins in filamentous fungi. PMID:21723343

Dave, Kashyap; Punekar, Narayan S

2011-09-10

54

Production of extremophilic bacterial cellulase enzymes in aspergillus niger.  

SciTech Connect

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

Gladden, John Michael

2013-09-01

55

Production of glucose oxidase using Aspergillus niger and corn steep liquor  

Microsoft Academic Search

Glucose oxidase production was optimized using an isolated strain of Aspergillus niger and an economical nutrient source, corn steep liquor (CSL). The culture produced 580±30 units\\/ml of the enzyme using 70 g\\/l sucrose as the carbon source. Using CSL as the sole nutrient source enzyme synthesis was increased to 640±36 units\\/ml. None of the nitrogen sources (nitrates of calcium, sodium,

R. P. Kona; N. Qureshi; J. S. Pai

2001-01-01

56

Tensidols, new potentiators of antifungal miconazole activity, produced by Aspergillus niger FKI-2342.  

PubMed

Two new furopyrrols, designated tensidols A and B, were isolated from the culture broth of Aspergillus niger FKI-2342 by solvent extraction, silica gel column chromatography and HPLC. Their structures were elucidated and shown to have the common skeleton of 6-benzyl-6H-furo[2,3-b]pyrrole. Tensidols A and B potentiated miconazole activity against Candida albicans. Tensidols also showed moderate antimicrobial activity only against Pyricularia oryzae. PMID:17080684

Fukuda, Takashi; Hasegawa, Yoko; Hagimori, Keiichi; Yamaguchi, Yuichi; Masuma, Rokuro; Tomoda, Hiroshi; Omura, Satoshi

2006-08-01

57

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

SciTech Connect

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

Kang, Seong-Woo; Kim, Seung-Woo [Univ. of Suwon (Korea, Republic of); Lee, Jin-Suk [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

1995-05-01

58

Production of fructose from inulin using mixed inulinases from Aspergillus niger and Candida guilliermondii  

Microsoft Academic Search

Two new effective microbial producers of inulinases were isolated from Jerusalem artichoke tubers grown in Thailand and identified\\u000a as Aspergillus niger TISTR 3570 and Candida\\u000a guilliermondii TISTR 5844. The inulinases produced by both these microorganisms were appropriate for hydrolysing inulin to fructose as the\\u000a principal product. An initial inulin concentration of ?100 g l?1 and the enzyme concentration of 0.2 U g?1 of

Sarote Sirisansaneeyakul; Nisakorn Worawuthiyanan; Wirat Vanichsriratana; Penjit Srinophakun; Yusuf Chisti

2007-01-01

59

Catalytic Properties of Lipase Extracts from Aspergillus niger  

Microsoft Academic Search

Summary Screening of lipolytic strains using Rhodamine-B\\/olive oil plate technique allowed the selection of Aspergillus niger MYA 135. Lipase production in submerged culture containing 2 % olive oil was enhanced by more than 50 % compared to basal cultural conditions. Op- timal catalytic conditions for olive oil-induced lipase were pH=6.5 and 30-35 °C. These values were shifted to the acid

Licia M. Pera; Cintia M. Romero; Mario D. Baigori; Guillermo R. Castro

2006-01-01

60

Sodium gluconate production by Aspergillus niger with intermittent broth replacement  

Microsoft Academic Search

Intermittent broth replacement was carried out to enhance the productivity and purity of sodium gluconate usingAspergillus niger by reducing the concentration of unmetabolized glucose. As inoculum size increased, length of lag phase was shortened and\\u000a high initial production rate of sodium gluconate was achieved. However, too high inoculum concentration lowered productivity\\u000a during the later stage of fermentation and increased residual

Sang-Yoon Lee; Bu-Su Park; Jin-Hyup Kim; Byung-Gee Kim; Dong-Il Kim

1999-01-01

61

Genetic analysis of benzoate metabolism in Aspergillus niger  

Microsoft Academic Search

The benzoate metabolism of Aspergillus niger was studied as part of a design to clone the benzoate-4-hydroxylase gene of this fungus on the basis of complementation. Filtration enrichment techniques yielded mutants defective for different steps of benzoate degradation: bph (benzoate-4-hydroxylase), phh (4-hydroxybenzoate-3-hydroxylase) and prc (protocatechuate ring cleavage) mutants. In this way the degradation pathway for benzoate, involving the formation of

J. G. Boschloo; A. Paffen; T. Koot; W. J. J. van den Tweel; R. F. M. van Gorcom; J. H. G. Cordewener; C. J. Bos

1990-01-01

62

Characterization of the Aspergillus niger prtT, a unique regulator of extracellular protease encoding genes.  

PubMed

Expression of several Aspergillus niger genes encoding major secreted, but not vacuolar, protease genes including the major acid protease gene pepA, was shown to be affected in the previously isolated A. niger protease mutant, AB1.13 [Mattern, I.E., van Noort, J.M., van den Berg, P., Archer, D.A., Roberts, I.N., Hondel, C.A.M.J.J., 1992. Isolation and characterization of mutants of Aspergillus niger deficient in extracellular proteases. Molecular & General Genetics 2, 332-336]. Complementation cloning of the putative protease-regulatory gene affected in this mutant was accomplished using a functional selection approach based on the use of the A. nidulans amdS selection marker driven by the A. niger pepA promoter. As expected the PpepA::amdS selection marker is not expressed in the mutant. Introduction of a self-replicating cosmid library into the mutant strain carrying the PpepA::amdS marker allowed selection of AmdS+ transformants functionally complementing the proposed regulatory mutation. Analysis of complementing cosmid clones revealed that the complementing sequences contained a gene encoding a member of the fungal-specific Zn2Cys6-binuclear cluster protein family. Sequence comparison of the encoded protein, PrtT, showed that it has homologues among different Aspergillus species. The A. oryzae homologue was shown to govern expression of the major alkaline protease AlpA and neutral protease Np1 in this species. In contrast to several other pathway specific regulators, such as AmyR and XlnR, no PrtT orthologues could be found in any other non-Aspergillus (or related) species and surprisingly, also not in Aspergillus nidulans. Interestingly, in all Aspergillus species carrying a prtT orthologue the gene is tightly clustered to a completely syntenous region carrying an amylolytic gene cluster including another Zn2Cys6-binuclear cluster protein, AmyR. Northern analysis of the A. niger prtT gene showed (constitutive) expression from two upstream promoters about 700 bp apart. The presence of several short upstream open reading frames downstream of both the distal and the proximal transcription start point of the prtT gene suggests regulation at the post-translational level. Also regulation at the level of differential splicing is suggested by the fact that several Aspergillus EST databases carry a considerable fraction of clones in which in frame intron sequences are retained. PMID:18930158

Punt, Peter J; Schuren, Frank H J; Lehmbeck, Jan; Christensen, Tove; Hjort, Carsten; van den Hondel, Cees A M J J

2008-12-01

63

Isolation of four pepsin-like protease genes from Aspergillus niger and analysis of the effect of disruptions on heterologous laccase expression.  

PubMed

Four new aspartic protease genes pepAa, pepAb, pepAc and pepAd from Aspergillus niger were identified using a comparative genomic approach. All four gene products have highly conserved attributes that are characteristic of aspartic proteases; however, each one has novel sequence features. The PEPAa protease appears to represent an ortholog of a pepsin-type aspartic protease previously identified from Talaromyces emersonii and Scleotinia sclerotiorum. The PEPAb protease appears to be an ortholog of an aspartic protease previously identified from BcAP1 of Botryotinia fuckeliana. The PEPAc protease also appears to be an ortholog of BcAP5 from B. fuckeliana. These four genes appear to be conserved in many species of filamentous fungi, all except PEPAb contain a predicted signal peptide. Transcriptome analysis revealed that transcripts of the pepAa gene of Aspergillus nidulans were significantly up-regulated due to recombinant chymosin secretion, suggesting that silencing these genes may lead to improved yields of secreted proteins. To establish the effects of reduced protease activity on the stabilities of secreted proteins, three of the four genes were individually disrupted by double crossover, although we were unable to disrupt the pepAc gene. The secretion level of heterologous laccase in the pepAa, pepAb and pepAd disruption mutants were increased by about 21%, 42% and 30%, respectively. And their total glucogenic enzymes secretion were also increased by about 18.7%, 37.0% and 5.20%, respectively. PMID:17977034

Wang, Yongchao; Xue, Wei; Sims, Andrew H; Zhao, Chuntian; Wang, Aoquan; Tang, Guomin; Qin, Junchuan; Wang, Huaming

2008-01-01

64

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

2013-01-01

65

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

66

Production of bio-ethanol from corncobs using Aspergillus niger and Saccharomyces cerevisae in simultaneous saccharification and fermentation  

Microsoft Academic Search

Maize is the most abundant cereal grown in Ghana and is accompanied by enormous amount of agrowastes of which corncobs form 30%. This agrowaste which is currently under utilized was used to produce bio-ethanol. Aspergillus niger isolated from soil sampled from Ejura farms was used to hydrolyze the corncobs into simple sugars. Filtrate obtained from corncobs broth fermented by A.

H. D. Zakpaa; E. E. Mak-Mensah; F. S. Johnson

2009-01-01

67

Influence of manganese on morphology and cell wall composition of Aspergillus niger during citric acid fermentation  

Microsoft Academic Search

Morphology and cell wall composition of Aspergillus niger were studied under conditions of manganese sufficient or deficient cultivation in an otherwise citric acid producing medium. Omission of Mn2+ (less than 10-7 M) from the nutrient medium of Aspergillus niger results in abnormal morphological development which is characterized by increased spore swelling, and squat, bulbeous hyphae. Fractionation and analysis of manganese

Monika Kisser; C. P. Kubicek; M. Röhr

1980-01-01

68

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

2009-01-01

69

Bioremediation of CCA-C treated wood by Aspergillus niger fermentation  

Microsoft Academic Search

This study evaluated the potential of the fungus Aspergillus niger to remove copper, chromium, and arsenic from waste wood treated with chromated copper arsenate (CCA) wood preservative. The removal of heavy metals by A. niger was carried out in two stages. In the first stage, A. niger was cultivated in carbohydrates media in order to produce large quantities of oxalic

S. N. Kartal; T. Kakitani; Y. Imamura

2004-01-01

70

Isolation of protoplasts from Aspergillus nidulans conidiospores.  

PubMed

Protoplasts were prepared from conidiospores of Aspergillus nidulans. The mononucleated conidia gave protoplasts of a uniform size, approximately 5-micron diameter, depending on the strain and the stabilizing medium used. Conidia were preincubated with 2-deoxy-D-glucose in a minimal medium at 37 degrees C for 3 h. The swollen conidia were collected, resuspended in a buffer containing 0.4 M (NH4)2SO4 as stabilizer, and incubated with Oerskovia lytic enzymes at 30 degrees C for 3 or 4 h. Approximately 80% of the conidia were converted into protoplasts. The protoplasts were separated from cell wall fragments and intact conidia by centrifugation over 30% sucrose. This isolation procedure gives a suspension of mononucleated or binucleated protoplasts suitable for recombination experiments and other studies for which a homogenous protoplast suspension is required. The procedure was also successful for Aspergillus niger. PMID:7016284

Bos, C J; Slakhorst, S M

1981-04-01

71

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

2013-06-01

72

A novel selectable marker based on Aspergillus niger arginase expression.  

PubMed

Selectable markers are valuable tools in transforming asexual fungi like Aspergillus niger. An arginase (agaA) expression vector and a suitable arginase-disrupted host would define a novel nutritional marker/selection for transformation. The development of such a marker was successfully achieved in two steps. The single genomic copy of A. niger arginase gene was disrupted by homologous integration of the bar marker. The agaA disruptant was subsequently complemented by transforming it with agaA expression vectors. Both citA and trpC promoters were able to drive the expression of arginase cDNA. Such agaA+ transformants displayed arginase expression pattern distinct from that of the parent strain. The results are also consistent with a single catabolic route for arginine in this fungus. A simple yet novel arginine-based selection for filamentous fungal transformation is thus described. PMID:22579391

Dave, Kashyap; Ahuja, Manmeet; Jayashri, T N; Sirola, Rekha Bisht; Punekar, Narayan S

2012-06-10

73

Targeted Lipid Analysis of Haemolytic Mycelial Extracts of Aspergillus niger.  

PubMed

Ethanolic extracts of mycelia from Aspergillus niger (strain N402) grown in liquid media were observed to have haemolytic activity on bovine erythrocytes. This haemolytic activity decreased significantly during the time of growth (1-3 days). Moreover, when A. niger was grown on carbon-deprived medium, the efficiency of this haemolytic activity in the ethanolic extracts was much lower than when grown in carbon-enriched medium, and became almost undetectable after 3 days of growth in carbon-deprived medium. The lipid composition of these ethanolic extracts was analysed by liquid chromatography-electrospray ionisation tandem mass spectrometry. This haemolytic activity can be mainly linked to the relative levels of the molar ratios of the unsaturated fatty acids and lysophosphatidylcholines. PMID:24983857

Novak, Maruša; Sep?i?, Kristina; Kraševec, Nada; Križaj, Igor; Ma?ek, Peter; Anderluh, Gregor; Guella, Graziano; Mancini, Ines

2014-01-01

74

Arabinase gene expression in Aspergillus niger: indications for coordinated regulation.  

PubMed

Aspergillus niger secretes three glycosylated glycosyl hydrolases which are involved in degradation of the plant cell wall polysaccharide L-arabinan: alpha-L-arabinofuranosidases (ABF) A and B, and endo-1,5-alpha-L-arabinase (ABN) A. The nucleotide sequence of the previously cloned gene encoding ABF A (abfA) from A. niger was determined. The coding region contains seven introns. Mature ABF A comprises 603 amino acids with a molecular mass of 65.4 kDa as deduced from the nucleotide sequence. The secreted enzyme is N-glycosylated. The primary structures of the three A. niger arabinases characterized lack similarity. Regulation of arabinase expression upon induction by sugar beet pulp and by L-arabitol was studied as a function of time. This was done in wild-type A. niger as well as in transformants carrying multiple copies of either one of the ABF-encoding genes. Each arabinase gene responded differently upon a mycelial transfer to L-arabitol-containing medium. Extra copies of abfA or abfB led to a decreased expression level of ABN A, though the repression elicited by abfB is stronger and more persistent than that effected by abfA. Multiple copies of both abf genes influence expression of the other ABF similarly, but to a far less pronounced degree than they affect ABN A synthesis. Four putative promoter elements, shared by all three arabinase genes, could be involved in coordination of L-arabinan degradation by A. niger. PMID:8000538

Flipphi, M J; Visser, J; van der Veen, P; de Graaff, L H

1994-10-01

75

Cloning of the Aspergillus niger gene encoding alpha-L-arabinofuranosidase A.  

PubMed

Using L-arabitol as an inducer, simple induction conditions were established that resulted in high-level expression of alpha-L-arabinofuranosidase A by an Aspergillus niger D-xylulose kinase mutant strain. These conditions were adapted to construct a cDNA expression library from which an alpha-L-arabinofuranosidase A cDNA clone was isolated using specific antiserum. The corresponding gene encoding alpha-L-arabinofuranosidase A (abfA) was isolated from a genomic library and cloned into a high copy plasmid vector. By co-transformation of uridine auxotrophic mutants lacking orotidine-5-phosphate decarboxylase activity, the afbA gene was introduced both in A. niger and A. nidulans, using the A. niger pyrA gene as selection marker. The identity of the abfA gene was confirmed by overexpression of the gene product by A. niger and A. nidulans transformants, upon growth using sugar beet pulp as the carbon source. PMID:7764056

Flipphi, M J; Visser, J; van der Veen, P; de Graaff, L H

1993-06-01

76

An insight into the curdione biotransformation pathway by Aspergillus niger.  

PubMed

Curdione (1), a sesquiterpene with a germacrane skeleton from rhizomes of Curcuma wenyujin, has attracted attention due to its important pharmacological properties. Herein, we investigated the chemo-biotransformation of curdione (1) systematically using Aspergillus niger AS 3.739. Regio- and stereoselective hydroxylation of curdione with filamentous fungus A. niger AS 3.739 led to seven metabolites including four new compounds 3?-hydroxycurcumalactone, 2?-hydroxycurcumalactone, (10S)-9,10-dihydroxy-curcumalactone and (10R)-9,10-dihydroxy-curcumalactone. Their structures were determined by spectroscopic techniques including two-dimensional NMR and TOF-MS (Time of Flight Mass Spectrometry). Based upon the analysis of biological and chemical conversions of curdione, a tentative metabolic pathway via chemo-bio cascade reactions is proposed in A. niger system, which provides an insight into the corresponding metabolism of curdione in animal systems. In addition, experiments with selected monooxygenase inhibitors suggest that cytochrome P450 monooxygenase played a crucial role in the hydroxylation of curdione. PMID:24456521

Chen, Yinan; Zhang, Lang; Qin, Bin; Zhang, Xin; Jia, Xian; Wang, Xiaoying; Jin, Danni; You, Song

2014-01-01

77

Lethal effects of Aspergillus niger against mosquitoes vector of filaria, malaria, and dengue: a liquid mycoadulticide.  

PubMed

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 LC(50), LC(90), and LC(99) 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/cm(2), after exposure of seven hours. We have calculated significant LT(90) values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0 hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides. PMID:22629156

Singh, Gavendra; Prakash, Soam

2012-01-01

78

Production of Proteolytic Enzymes by a Keratin-Degrading Aspergillus niger  

PubMed Central

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

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

2011-01-01

79

Heterologous expression of manganese peroxidase in Aspergillus niger and its effect on phenanthrene removal from soil.  

PubMed

A strain of Aspergillus niger, previously isolated from sugarcane bagasse because of its capacity to degrade phenanthrene in soil by solid culture, was used to express a manganese peroxidase gene (mnp1) from Phanerochaete chrysosporium, aiming at increasing its polycyclic aromatic hydrocarbons degradation capacity. Transformants were selected based on their resistance to hygromycin B and the discoloration induced on Poly R-478 dye by the peroxidase activity. The recombinant A. niger SBC2-T3 strain developed MnP activity and was able to remove 95% of the initial phenanthrene (400 ppm) from a microcosm soil system after 17 days, whereas the wild strain removed 72% under the same conditions. Transformation success was confirmed by PCR amplification using gene-specific primers, and a single fragment (1,348 bp long, as expected) of the recombinant mnp1 was amplified in the DNA from transformants, which was absent from the parental strain. PMID:22286039

Cortés-Espinosa, Diana V; Absalón, Ángel E; Sanchez, Noé; Loera, Octavio; Rodríguez-Vázquez, Refugio; Fernández, Francisco J

2011-01-01

80

Characterization of a Foldase, Protein Disulfide Isomerase A, in the Protein Secretory Pathway of Aspergillus niger  

PubMed Central

Protein disulfide isomerase (PDI) is important in assisting the folding and maturation of secretory proteins in eukaryotes. A gene, pdiA, encoding PDIA was previously isolated from Aspergillus niger, and we report its functional characterization here. Functional analysis of PDIA showed that it catalyzes the refolding of denatured and reduced RNase A. pdiA also complemented PDI function in a Saccharomyces cerevisiae ?pdi1 mutant in a yeast-based killer toxin assay. Levels of pdiA mRNA and PDIA protein were raised by the accumulation of unfolded proteins in the endoplasmic reticulum. This response of pdiA mRNA levels was slower and lower in magnitude than that of A. niger bipA, suggesting that the induction of pdiA is not part of the primary stress response. An increased level of pdiA transcripts was also observed in two A. niger strains overproducing a heterologous protein, hen egg white lysozyme (HEWL). Although overexpression of PDI has been successful in increasing yields of some heterologous proteins in S. cerevisiae, overexpression of PDIA did not increase secreted yields of HEWL in A. niger, suggesting that PDIA itself is not limiting for secretion of this protein. Downregulation of pdiA by antisense mRNA reduced the levels of microsomal PDIA activity by up to 50%, lowered the level of PDIA as judged by Western blots, and lowered the secreted levels of glucoamylase by 60 to 70%.

Ngiam, Celina; Jeenes, David J.; Punt, Peter J.; Van Den Hondel, Cees A. M. J. J.; Archer, David B.

2000-01-01

81

Inactivation of Aspergillus niger in mango nectar by high-pressure homogenization combined with heat shock.  

PubMed

This research evaluated the inactivation of a heat-resistant Aspergillus niger conidia in mango nectar by high-pressure homogenization (HPH) combined with heat shock. A. niger were inoculated in mango nectar (10(6) conidia mL(-1)) and subjected to HPH (300 to 100 MPa) and heat shock (80 degrees C for 5 to 20 min) before or after HPH. Processes were evaluated according to number of decimal reductions reached by each isolated or combined process. Scanning electron microscopy was performed to observe conidia wall after pressure treatment. Pressures below 150 MPa did not inactivate A. niger while pressures of 200 and 300 MPa resulted in 2 and more than 6 log reductions, respectively. D(80 degrees C) of A. niger was determined as 5.03 min. A heat shock of 80 degrees C/15 min, reaching 3 decimal conidia reductions, was applied before or after a 200 MPa pressure treatment to improve the decimal reduction to 5 log cycles. Results indicated that HPH inactivated A. niger in mango nectar at 300 MPa (>6.24 log cycles) and that, with pressure (200 MPa) combined with post heat shock, it was possible to obtain the same decimal reduction, showing a synergistic effect. On the other hand, pre heat shock associated with HPH resulted in an additive effect. The observation of A. niger conidia treated by HPH at 100 and 200 MPa by scanning electron microscopy indicated that HPH promoted intense cell wall damage, which can sensitize the conidia to post heat shock and possibly explain the synergistic effect observed. Practical Application: The results obtained in this paper are relevant to elucidate the mechanism of conidia inactivation in order to develop the application of HPH as an alternative pasteurization process for the fruit nectar industry. PMID:20492122

Tribst, Alline A L; Franchi, Mark A; Cristianini, Marcelo; de Massaguer, Pilar R

2009-01-01

82

Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger  

SciTech Connect

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

Choudhury, Samrat Roy; Goswami, Arunava [Agricultural and Ecological Research Unit, Biological Sciences Division, Indian Statistical Institute, 203 B. T. Road, Kolkata, West Bengal-700108 (India); Nair, Kishore K.; Kumar, Rajesh; Gopal, Madhuban; Devakumar, C. [Department of Agricultural Chemicals, Pusa Campus, New Delhi (India); Gogoi, Robin [Plant Pathology, Pusa Campus, New Delhi (India); Srivastava, Chitra; Subhramanyam, B. S. [Entomology, Indian Agricultural Research Institute, Pusa Campus, New Delhi (India)

2010-10-04

83

Tandem shock waves to enhance genetic transformation of Aspergillus niger.  

PubMed

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

Loske, Achim M; Fernández, Francisco; Magańa-Ortíz, Denis; Coconi-Linares, Nancy; Ortíz-Vázquez, Elizabeth; Gómez-Lim, Miguel A

2014-08-01

84

Antimicrobial textile treated with chitosan from Aspergillus niger mycelial waste.  

PubMed

The waste biomass of Aspergillus niger, following citric acid production, was used as a source for fungal chitosan extraction. The produced chitosan was characterized with deacetylation degree of 89.6%, a molecular weight of 25,000 dalton, 97% solubility in 1% acetic acid solution and comparable FT-IR spectra to standard shrimp chitosan. Fungal chitosan was applied as a cotton fabric finishing agent using pad-dry-cure method. The topographical structure of chitosan-treated fabrics (CTF) was much improved compared with control fabrics. CTF, after durability tests, exhibited a powerful antimicrobial activity against both E. coli and Candida albicans, the captured micrographs for E. coli cells contacted with CTF showed a complete lysis of cell walls with the prolonging contact time. The produced antimicrobial CTF could be proposed as a suitable material for many medical and hygienic applications. PMID:21596059

Tayel, Ahmed A; Moussa, Shaaban H; El-Tras, Wael F; Elguindy, Nihal M; Opwis, Klaus

2011-08-01

85

Structure of the catalytic domain of glucoamylase from Aspergillus niger.  

PubMed

Glucoamylase from Aspergillus niger is an industrially important biocatalyst that is utilized in the mass production of glucose from raw starch or soluble oligosaccharides. The G1 isoform consists of a catalytic domain and a starch-binding domain connected by a heavily glycosylated linker region. The amino-terminal catalytic domain of the G1 isoform generated by subtilisin cleavage has been crystallized at pH 8.5, which is a significantly higher pH condition than used for previously characterized glucoamylase crystals. The refined structure at 1.9 Ĺ resolution reveals the active site of the enzyme in complex with both Tris and glycerol molecules. The ligands display both unique and analogous interactions with the substrate-binding site when compared with previous structures of homologous enzymes bound to inhibitors. PMID:21301084

Lee, Jaeyong; Paetzel, Mark

2011-02-01

86

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

SciTech Connect

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

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

2004-04-01

87

Bioleaching of spent fluid catalytic cracking catalyst using Aspergillus niger.  

PubMed

The use of the fungus Aspergillus niger for the bioleaching of heavy metals from spent catalyst was investigated, with fluid catalytic cracking (FCC) catalyst as a model. Bioleaching was examined in batch cultures with the spent catalysts at various pulp densities (1-12%). Chemical leaching was also performed using mineral acids (sulphuric and nitric acids) and organic acids (citric, oxalic and gluconic acids), as well as a mixture of organic acids at the same concentrations as that biogenically produced. It was shown that bioleaching realised higher metal extraction than chemical leaching, with A. niger mobilizing Ni (9%), Fe (23%), Al (30%), V (36%) and Sb (64%) at 1% pulp density. Extraction efficiency generally decreased with increased pulp density. Compared with abiotic controls, bioleaching gave rise to higher metal extractions than leaching using fresh medium and cell-free spent medium. pH decreased during bioleaching, but remained relatively constant in both leaching using fresh medium and cell-free spent medium, thus indicating that the fungus played a role in effecting metal extraction from the spent catalyst. PMID:15664080

Aung, Khin Moh Moh; Ting, Yen-Peng

2005-03-16

88

Starch-binding domain shuffling in Aspergillus niger glucoamylase.  

PubMed

Aspergillus niger glucoamylase (GA) consists mainly of two forms, GAI [from the N-terminus, catalytic domain + linker + starch-binding domain (SBD)] and GAII (catalytic domain + linker). These domains were shuffled to make RGAI (SBD + linker + catalytic domain), RGAIDeltaL (SBD + catalytic domain) and RGAII (linker + catalytic domain), with domains defined by function rather than by tertiary structure. In addition, Paenibacillus macerans cyclomaltodextrin glucanotransferase SBD replaced the closely related A.niger GA SBD to give GAE. Soluble starch hydrolysis rates decreased as RGAII approximately GAII approximately GAI > RGAIDeltaL approximately RGAI approximately GAE. Insoluble starch hydrolysis rates were GAI > RGAIDeltaL > RGAI > GAE approximately RGAII > GAII, while insoluble starch-binding capacities were GAI > RGAI > RGAIDeltaL > RGAII > GAII > GAE. These results indicate that: (i) moving the SBD to the N-terminus or replacing the native SBD somewhat affects soluble starch hydrolysis; (ii) SBD location significantly affects insoluble starch binding and hydrolysis; (iii) insoluble starch hydrolysis is imperfectly correlated with its binding by the SBD; and (iv) placing the P.macerans cyclomaltodextrin glucanotransferase SBD at the end of a linker, instead of closely associated with the rest of the enzyme, severely reduces its ability to bind and hydrolyze insoluble starch. PMID:12915730

Cornett, Catherine A G; Fang, Tsuei-Yun; Reilly, Peter J; Ford, Clark

2003-07-01

89

Optimized bioprocess for production of fructofuranosidase by recombinant Aspergillus niger.  

PubMed

A comprehensive approach of bioprocess design at various levels was used to optimize microbial production of extracellular fructofuranosidase, important as biocatalyst to derive fructooligosaccharides with broad application in food or pharmaceutical 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 towards an optimized medium, glucose, nitrate, Fe(2+), and Mn(2+) were identified as beneficial for production. A minimal medium with optimized concentration of these key nutrients, obtained by central composite design experiments and quadratic modelling, provided a threefold increased fructofuranosidase activity in the culture supernatant (400 U/mL) as compared to the originally described medium. Utilizing the optimized medium, the process was then transferred from shake flask into a fed-batch-operated bioreactor. Hereby, the intended addition of talc microparticles allowed engineering the morphology of A. niger into a highly active mycelial form, which strongly boosted production. Fructofuranosidase production was highly specific as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The secreted enzyme activity of 2,800 U/mL, corresponding to about 3 g/L of fructofuranosidase, achieved by the microparticle-enhanced fed-batch process, is tenfold higher than that of any other process reported so far, so that the presented bioprocess strategy appears as a milestone towards future industrial fructofuranosidase production. PMID:20502893

Driouch, Habib; Roth, Andreas; Dersch, Petra; Wittmann, Christoph

2010-08-01

90

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; Castańo-Tostado, E; Guevara-González, R G; Loera, O; Regalado, C

2011-09-01

91

Physiological characterization of ATP-citrate lyase in Aspergillus niger.  

PubMed

Acetyl-CoA, an important molecule in cellular metabolism, is generated in multiple subcellular compartments and mainly used for energy production, biosynthesis of a diverse set of molecules, and protein acetylation. In eukaryotes, cytosolic acetyl-CoA is derived mainly from the conversion of citrate and CoA by ATP-citrate lyase. Here, we describe the targeted deletions of acl1 and acl2, two tandem divergently transcribed genes encoding subunits of ATP-citrate lyase in Aspergillus niger. We show that loss of acl1 or/and acl2 results in a significant decrease of acetyl-CoA and citric acid levels in these mutants, concomitant with diminished vegetative growth, decreased pigmentation, reduced asexual conidiogenesis, and delayed conidial germination. Exogenous addition of acetate repaired the defects of acl-deficient strains in growth and conidial germination but not pigmentation and conidiogenesis. We demonstrate that both Acl1 and Acl2 subunits are required to form a functional ATP-citrate lyase in A. niger. First, deletion of acl1 or/and acl2 resulted in similar defects in growth and development. Second, enzyme activity assays revealed that loss of either acl1 or acl2 gene resulted in loss of ATP-citrate lyase activity. Third, in vitro enzyme assays using bacterially expressed 6His-tagged Acl protein revealed that only the complex of Acl1 and Acl2 showed ATP-citrate lyase activity, no enzyme activities were detected with the individual protein. Fourth, EGFP-Acl1 and mCherry-Acl2 proteins were co-localized in the cytosol. Thus, acl1 and acl2 coordinately modulate the cytoplasmic acetyl-CoA levels to regulate growth, development, and citric acid synthesis in A. niger. PMID:24566752

Chen, Hong; He, Xihong; Geng, Hongran; Liu, Hao

2014-04-01

92

Phytase activity in Aspergillus fumigatus isolates.  

PubMed

Extracellular phytase from Aspergillus fumigatus isolates was characterized and their genes were cloned and sequenced. Based on their banding pattern in SDS-PAGE all phytases were found to be glycosylated and have similar molecular mass. A correlation between lower optimum pH (4.0) and a higher optimum temperature (70 degrees C) was found in these enzymes. All enzymes characterized displayed a lower specific activity for phytic acid and were more susceptible to proteolytic degradation than the Aspergillus niger phytase that is now commercially available. DNA sequencing established almost no sequence variation in any of the genes and no correlation is evident between a specific amino acid sequence and any physicochemical and catalytic properties of the enzymes. Despite two of the isolates having identical deduced amino acid sequence, characterization of the enzymes encoded by these two identical genes revealed differences in both pH and temperature optimum. This suggests that differences in pH and temperature optimum in these four isolates of A. fumigatus may be due in part to subtle differences in posttranslational modification. PMID:10973795

Mullaney, E J; Daly, C B; Sethumadhavan, K; Rodriquez, E; Lei, X G; Ullah, A H

2000-09-01

93

Ram horn peptone as a source of citric acid production by Aspergillus niger , with a process  

Microsoft Academic Search

The present study deals with the production of citric acid from a ram horn peptone (RHP) by Aspergillus niger NRRL 330. A medium from RHP and a control medium (CM) were compared for citric acid production using A. niger in a batch culture. For this purpose, first, RHP was produced. Ram horns were hydrolyzed by treatment with acids (6 N H

Esabi B. Kurbanoglu; Namudar I. Kurbanoglu

2004-01-01

94

Production of Single Cell Protein in Stickwater by Lactobacillus acidophilus and Aspergillus niger  

Microsoft Academic Search

The aim of this study was to investigate production of single cell protein (SCP) using Lactobacillus acidophilus and Aspergillus niger in stickwater from fish meal factories. Stickwater was used as substrate for L. acidophilus and A. niger and compared with standard medium as control. The maximum chemical oxygen demand reduction by L. acidophilus was achieved at 55.4 and 86.4% and

Safarbibi Kam; Abdolmohammad Abedian Kenari; Habibollah Younesi

2011-01-01

95

Apple pomace: A potential substrate for citric acid production by Aspergillus niger  

Microsoft Academic Search

Apple pomace was used as a fsubstrate for citric acid production by five strains of Aspergillus niger. A. niger NRRL 567 produced the greatest amount of citric acid from apple pomace in the presence of 4% methanol. The yield was 88% based on the amount of sugar consumed.

Y. D. Hang; E. E. Woodams

1984-01-01

96

Citric Acid Production by Aspergillus niger Using Date-Based Medium Fortified with Whey and Additives  

Microsoft Academic Search

The ability of Aspergillus niger to produce citric acid from dates was evaluated. Two strains of A. niger (ATCC 6275 and 9642) were grown in media containing different concentrations of date extract or molasses fortified with whey, methanol and tricalcium phosphate. The fermentation experiments were conducted at 25° C for 12 days and samples were withdrawn at different time intervals

G. F. Mehyar; K. S. Delaimy; S. A. Ibrahim

2005-01-01

97

Biotransformation of one monoterpene by sporulated surface cultures of Aspergillus niger and Penicillium sp.  

PubMed

In this study, biotransformation of menthol by sporulated surface culture of Aspergillus niger and Penicillium sp. was studied. The main bioconversion product obtained from menthol of A. niger was cis-p-menthan-7-ol and the main products obtained by surface Penicillium sp. were limonene, p-cymene and gamma-terpinene using sporulated surface culture. The pathways involved in the biotransformation of menthol by A. niger and Penicillium sp. to main products are also discussed. PMID:19521921

Esmaeili, Akbar; Sharafian, Shirin; Safaiyan, Shila; Rezazadeh, Shamsali; Rustaivan, Abdolhossein

2009-01-01

98

Derepressed 2-deoxyglucose-resistant mutants of Aspergillus niger with altered hexokinase and acid phosphatase activity in hyperproduction of ?-fructofuranosidase  

Microsoft Academic Search

Aspergillus niger NRRL330 produces extracellular ?-fructofuranosidase (Ffase), and its production is subject to repression by hexoses in the\\u000a medium. After ultraviolet mutagenization and selection, seven derepressed mutants resistant to 2-deoxyglucose (2-DG) were\\u000a isolated on Czapek’s minimal medium containing glycerol. One of the mutants, designated DGRA-1, produced higher levels of\\u000a Ffase. A considerable difference occurred in the mutants with reference to

B. Ashokkumar; S. R. Senthilkumar; P. Gunasekaran

2004-01-01

99

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

100

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

PubMed

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

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

2010-02-01

101

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

PubMed

The effect of water activity (a(w)) (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 rDNA Restriction Fragment Length Polymorphism (RFLP) pattern. They were characterized by Random Amplification of Polymorphic DNA (RAPD) and ITS-5.8 S rDNA and 28 S rDNA (D1/D2) sequencing. Regardless of the a(w) value tested, YES was a better culture medium than CYA for OTA production. The a(w) range for OTA production was narrower than that for growth. OTA was produced from 0.90, 0.92, 0.94 or 0.96 to 0.99 a(w) depending on the strain and the culture medium. The molecular study differentiated strains into two groups which corresponded to the RFLP types N and T although it did not distinguish them by their source of isolation or OTA producing abilities. Our results show that A. niger aggregate strains are able to grow and produce OTA over a wide a(w) range. These results will lead to a better understanding of the contribution of A. niger aggregate in OTA contamination of food and feed. PMID:16443301

Esteban, A; Abarca, M L; Bragulat, M R; Cabańes, F J

2006-04-25

102

Cloning and characterization of three Aspergillus niger promoters.  

PubMed

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

Luo, X

1995-09-22

103

The composition of the cell wall of Aspergillus niger  

PubMed Central

1. The cell-wall composition of Aspergillus niger has been investigated. Analysis shows the presence of six sugars, glucose, galactose, mannose, arabinose, glucosamine and galactosamine, all in the d-configuration, except that a small amount of l-galactose may be present. Sixteen common amino acids are also present. 2. The wall consists chiefly of neutral carbohydrate (73–83%) and hexosamine (9–13%), with smaller amounts of lipid (2–7%), protein (0·5–2·5%) and phosphorus (less than 0·1%). The acetyl content (3·0–3·4%) corresponds to 1·0mole/mole of hexosamine nitrogen. 3. A fractionation of the cell-wall complex was achieved, with or without a preliminary phenol extraction, by using n-sodium hydroxide. Though this caused some degradation, 30–60% of the wall could be solubilized (depending on the preparation). Analyses on several fractions suggest that fractionation procedures bring about some separation of components although not in a clear-cut fashion. 4. Cell-wall preparations were shown to yield a fraction having [?]D approx. +240° (in n-sodium hydroxide) and consisting largely of glucose. This was separated into two subfractions, one of which had [?]D+281° (in n-sodium hydroxide) and had properties resembling the polysaccharide nigeran; the other had [?]D +231° (in n-sodium hydroxide). It is suggested that nigeran is a cell-wall component.

Johnston, I. R.

1965-01-01

104

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

PubMed Central

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

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

2011-01-01

105

Studies on sulfhydryl groups of Aspergillus niger amine oxidase.  

PubMed

Amino acid analysis of the amine oxidase of Aspergillus niger (monoamine:O2 oxidoreductase (deaminating), EC 1.4.3.4) showed a composition similar to that of bovine plasma enzyme. One molecule of enzyme contained 25 Cys residues. It was shown that 9 to 11 residues of Cys were titrated to be SH groups. The amine oxidase reaction was markedly inhibited by metal ions (Cu2+, Hg2+, Ag+). The enzyme was inactivated with SH reagents (phenyl mercuric acetate, Cl-HgBzO-) and the extent of this inactivation was dependent on the time of incubation with SH reagents. Also, the Cl-HgBzO- -inactivated enzyme was reactivated with cysteine and this reactivation was biphasic with the time of incubation. The Cl-HgBzO--inactivated amine oxidase was compared with the native enzyme in their reactivity with phenylhydrazine and their spectral properties. The results showed that the Cl-HgBzO--inactivated enzyme had lower reactivity with phenylhydrazine than the native enzyme and had higher absorbance values than the native enzyme around 400 nm wavelengths. PMID:1174546

Suzuki, H; Ogura, Y; Yamada, H; Arima, K

1975-09-22

106

Some factors affecting tannase production by Aspergillus niger Van Tieghem  

PubMed Central

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

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

2013-01-01

107

Population balance modeling of the conidial aggregation of Aspergillus niger.  

PubMed

Numerous biotechnological production processes are based on the submerse cultivation of filamentous fungi. Process design, however, is often hampered by the complex growth pattern of these organisms. In the morphologic development of coagulating filamentous fungi, like Aspergillus niger, conidial aggregation is the first step of filamentous morphogenesis. For a proper description of this phenomenon it is necessary to characterize conidial populations. Kinetic studies performed with an in-line particle size analyzer suggested that two distinct aggregation steps have to be considered. The first step of conidial aggregation starts immediately after inoculation. Both the rate constants of formation and disintegration of aggregates have been determined by measuring the concentration of conidia at the beginning of the cultivation and the concentration of particles at steady state during the first hours of cultivation. In contrast to the first aggregation step, where the collision of conidia is presumed to be responsible for the process, the second aggregation step is thought to be initiated by germination of conidia. Growing hyphae provide additional surface for the attachment of non- germinated conidia, which leads to a strong decrease in particle concentration. The specific hyphal length growth rate and the ratio of particle concentration to the growing adhesion hyphal surface are decisive matters of the second aggregation step. Both aggregation steps can be described by population dynamics and simulated using the program package PARSIVAL (PARticle SIze eVALution) for the treatment of general particle population balances. PMID:17625790

Lin, P-J; Grimm, L H; Wulkow, M; Hempel, D C; Krull, R

2008-02-01

108

Production of antifungal chitinase by Aspergillus niger LOCK 62 and its potential role in the biological control.  

PubMed

Aspergillus niger LOCK 62 produces an antifungal chitinase. Different sources of chitin in the medium were used to test the production of the chitinase. Chitinase production was most effective when colloidal chitin and shrimp shell were used as substrates. The optimum incubation period for chitinase production by Aspergillus niger LOCK 62 was 6 days. The chitinase was purified from the culture medium by fractionation with ammonium sulfate and affinity chromatography. The molecular mass of the purified enzyme was 43 kDa. The highest activity was obtained at 40 °C for both crude and purified enzymes. The crude chitinase activity was stable during 180 min incubation at 40 °C, but purified chitinase lost about 25 % of its activity under these conditions. Optimal pH for chitinase activity was pH 6-6.5. The activity of crude and purified enzyme was stabilized by Mg(2+) and Ca(2+) ions, but inhibited by Hg(2+) and Pb(2+) ions. Chitinase isolated from Aspergillus niger LOCK 62 inhibited the growth of the fungal phytopathogens: Fusarium culmorum, Fusarium solani and Rhizoctonia solani. The growth of Botrytis cinerea, Alternaria alternata, and Fusarium oxysporum was not affected. PMID:22922773

Brzezinska, Maria Swiontek; Jankiewicz, Urszula

2012-12-01

109

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

2012-05-01

110

Screening, mutagenesis and protoplast fusion of Aspergillus niger for the enhancement of extracellular glucose oxidase production.  

PubMed

Various strains of Aspergillus niger were screened for extracellular glucose oxidase (GOD) activity. The most effective producer, strain FS-3 (15.9 U mL(-1)), was mutagenized using UV-irradiation or ethyl methane sulfonate. Of the 400 mutants obtained, 32 were found to be resistant to 2-deoxy D: -glucose, and 17 of these exhibited higher GOD activities (from 114.5 to 332.1%) than the original FS-3 strain. Following determination of antifungal resistance of the highest producing mutants, four mutants were selected and used in protoplast fusions in three different intraspecific crosses. All fusants showed higher activities (from 285.5 to 394.2%) than the original strain. Moreover, of the 30 fusants isolated, 19 showed higher GOD activity than their corresponding higher-producing parent strain. PMID:15952011

Khattab, A A; Bazaraa, W A

2005-07-01

111

Inhibitory effects of sulfur nanoparticles on membrane lipids of Aspergillus niger: a novel route of fungistasis.  

PubMed

Orthorhombic (spherical; ~10 nm) and monoclinic (cylindrical; ~50 nm) sulfur nanoparticles (SNPs) were synthesized and examined for their effects on the total lipid content and desaturase enzymes of Aspergillus niger. Synthesized SNPs were characterized for size with transmission electron microscopy, elemental composition with energy dispersive X-ray spectroscopy and allotropic nature with X-ray diffraction pattern. Both the SNPs considerably reduced total lipid content of the treated fungal isolates with significant down regulation of the expression of various desaturase enzymes (linoleoyl-CoA desaturase, stearoyl-CoA 9-desaturase and phosphatidylcholine desaturase). Unusual high accumulation of saturated fatty acids with depleted lipid layer can be inferred as one of the major reasons of SNPs mediated fungistasis. PMID:22538469

Roy Choudhury, Samrat; Ghosh, Mahua; Goswami, Arunava

2012-07-01

112

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

113

New metal-binding ethyldiamino- and dicarboxy-products from Aspergillus niger industrial wastes  

Microsoft Academic Search

The metal-binding ability of Aspergillus niger mycelial waste was improved by chemical modification. The latter was performed by introducing additional carboxy groups using oxidation methods or the introduction of the ethyldiamino group first by chlorination of A. niger using mesyl chloride and subsequent reaction of the product with ethylene diamine. Metal binding abilities of the products for Cd2+, Co2+, Ni2+ and

Markus Krämer; Hans-Ulrich Meisch

1999-01-01

114

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

115

Production of vanillin from waste residue of rice bran oil by Aspergillus niger and Pycnoporus cinnabarinus  

Microsoft Academic Search

A new technology of transforming ferulic acid, which was from waste residue of rice bran oil, into vanillin was developed by a combination of fungal strains Aspergillus niger CGMCC0774 and Pycnoporus cinnabarinus CGMCC1115. Various concentrations of ferulic acid were compared, and the highest yield reached 2.2gl?1 of vanillic acid by A. niger CGMCC0774 in a 25l fermenter when concentration of

Lirong Zheng; Pu. Zheng; Zhihao Sun; Yanbing Bai; Jun Wang; Xinfu Guo

2007-01-01

116

Biosorption of phenol from an aqueous solution by Aspergillus niger biomass  

Microsoft Academic Search

Phenols in trace quantities are usually present in the treated effluent of many wastewater-treatment plants. Phenol contamination of drinking water even at 1 ?g\\/l concentration can cause significant taste and odor problems. This study investigates the use of non-viable pretreated cells of Aspergillus niger to remove phenol from an aqueous solution. Five types of non-viable pretreated A. niger biomass powders

J. R Rao; T Viraraghavan

2002-01-01

117

Production and characterization of extracellular protease of mutant Aspergillus niger AB 100 grown on fish scale  

Microsoft Academic Search

Fish scale, the chief waste material of fish processing industries was processed and tested for production of extracellular\\u000a protease by mutant Aspergillus niger AB100. Protease production by A. niger AB100 was greatly enhanced in presence of processed fish scale powder. Where as among the three complex nutrients tested, soya\\u000a bean meal shows maximum stimulatory effect over protease production (2,776 ?mol\\/ml\\/min) when

Barnali Ray Basu; Ajit K. Banik; Manas Das

2008-01-01

118

Calcium oxalate crystal deposition in a patient with Aspergilloma due to Aspergillus niger  

PubMed Central

Discrimination between aspergilloma and chronic necrotizing pulmonary aspergillosis (CNPA) based on radiological findings can difficult. We describe a patient with aspergilloma and organizing pneumonia that was possibly caused by Aspergillus niger infection and radiologically mimicked CNPA. A postmortem histological analysis showed diffuse alveolar damage that had originated in peri-cavitary lung parenchyma. Calcium oxalate or Aspergillus niger was located inside, but not outside the cavity in the right upper lobe. Calcium oxalate or other unknown hyphal bioactive components might provoke severe lung inflammation not only adjacent to the cavity, but also on the contralateral side.

Oda, Miku; Wakayama, Megumi; Shibuya, Kazutoshi; Ogawa, Yukari; Inui, Toshiya; Yokoyama, Emi; Inoue, Manami; Shimoyamada, Hiroaki; Fujiwara, Masachika; Ota, Tomohiro; Takizawa, Hajime; Goto, Hajime

2013-01-01

119

Efficient expression and secretion of Aspergillus niger RH5344 polygalacturonase in Saccharomyces cerevisiae  

Microsoft Academic Search

An Aspergillus niger endopolygalacturonase (EC 3.2.1.15) cDNA was expressed in the yeast Saccharomyces cerevisiae. Secretion of the protein into the growth medium was efficiently directed by the fungal leader sequence, and processing occurred at the same site as in Aspergillus. The expression level was significantly enhanced by using a “short” version of the yeast ADHI promoter. An additional increase in

C. Lang; A. C. Looman

1995-01-01

120

Purification and characterization of a nitrilase from Aspergillus niger K10  

Microsoft Academic Search

Aspergillus niger K10 cultivated on 2-cyanopyridine produced high levels of an intracellular nitrilase, which was partially purified (18.6-fold) with a 24% yield. The N-terminal amino acid sequence of the enzyme was highly homologous with that of a putative nitrilase from Aspergillus fumigatus Af293. The enzyme was copurified with two proteins, the N-terminal amino acid sequences of which revealed high homology

Ond?ej Kaplan; Vojt?ch Vejvoda; Ond?ej Plíhal; Petr Pompach; Daniel Kavan; Pavla Bojarová; Karel Bezouška; Martina Macková; Maria Cantarella; Vladimír Jirk?; Vladimír K?en; Ludmila Martínková

2006-01-01

121

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

2010-01-01

122

Characterization of oxylipins and dioxygenase genes in the asexual fungus Aspergillus niger  

PubMed Central

Background Aspergillus niger is an ascomycetous fungus that is known to reproduce through asexual spores, only. Interestingly, recent genome analysis of A. niger has revealed the presence of a full complement of functional genes related to sexual reproduction [1]. An example of such genes are the dioxygenase genes which in Aspergillus nidulans, have been shown to be connected to oxylipin production and regulation of both sexual and asexual sporulation [2-4]. Nevertheless, the presence of sex related genes alone does not confirm sexual sporulation in A. niger. Results The current study shows experimentally that A. niger produces the oxylipins 8,11-dihydroxy octadecadienoic acid (8,11-diHOD), 5,8-dihydroxy octadecadienoic acid (5,8-diHOD), lactonized 5,8-diHOD, 8-hydroxy octadecadienoic acid (8-HOD), 10-hydroxy octadecadienoic acid (10-HOD), small amounts of 8-hydroxy octadecamonoenoic acid (8-HOM), 9-hydroxy octadecadienoic acid (9-HOD) and 13-hydroxy octadecadienoic acid (13-HOD). Importantly, this study shows that the A. niger genome contains three putative dioxygenase genes, ppoA, ppoC and ppoD. Expression analysis confirmed that all three genes are indeed expressed under the conditions tested. Conclusion A. niger produces the same oxylipins and has similar dioxygenase genes as A. nidulans. Their presence could point towards the existence of sexual reproduction in A. niger or a broader role for the gene products in physiology, than just sexual development.

2009-01-01

123

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

PubMed

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

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

2011-01-01

124

Cloning, characterization and overexpression of the phytase-encoding gene (phyA) of Aspergillus niger.  

PubMed

Phytase catalyzes the hydrolysis of phytate (myo-inositol hexakisphosphate) to myo-inositol and inorganic phosphate. A gene (phyA) of Aspergillus niger NRRL3135 coding for extracellular, glycosylated phytase was isolated using degenerate oligodeoxyribonucleotides deduced from phytase amino acid (aa) sequences. Nucleotide (nt) sequence analysis of the cloned region revealed the presence of an open reading frame coding for 467 aa and interrupted once by an intron of 102 bp in the 5' part of the gene. The start codon is followed by a sequence coding for a putative signal peptide. Expression of phyA is controlled at the level of mRNA accumulation in response to inorganic phosphate levels. After cell growth in low-phosphate medium, a transcript of about 1.8 kb was visualized. Transcription of phyA initiates at at least seven start points within a region located 45-25 nt upstream from the start codon. In transformants of A. niger, expression of multiple copies of phyA resulted in up to more than tenfold higher phytase levels than in the wild-type strain. PMID:8387447

van Hartingsveldt, W; van Zeijl, C M; Harteveld, G M; Gouka, R J; Suykerbuyk, M E; Luiten, R G; van Paridon, P A; Selten, G C; Veenstra, A E; van Gorcom, R F

1993-05-15

125

Value of Aspergillus niger fermentation product as a dietary ingredient for broiler chickens  

Microsoft Academic Search

The experiment reported was a study on Aspergillus niger inoculation into the waste liquor from glutamate manufacturing and used as a dietary protein source for broilers. The program involved a toxicological and nutritional evaluation of the product using a short-term toxicity and a nutritional feeding trial in broilers. Both trials involved a total of 800 broilers from the commercial Arbor

Peter W. S Chiou; S. W Chiu; C. R Chen

2001-01-01

126

Optimization of glucose oxidase production by Aspergillus niger in a benchtop bioreactor using response surface methodology  

Microsoft Academic Search

Response surface methodology (RSM) was applied to optimize the speed of agitation and the rate of aeration for the maximum production of glucose oxidase (GOD) by Aspergillus niger. A 22 central composite design using RSM was employed in this investigation. A quadratic model for GOD production was obtained. Aeration had more negative effect on GOD production than agitation. Significant negative

Jian-Zhong Liu; Li-Ping Weng; Qian-Ling Zhang; Hong Xu; Liang-Nian Ji

2003-01-01

127

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...

128

Sorption of Heavy Metals by the Soil Fungi 'Aspergillus niger' and Mucor rouxii.  

National Technical Information Service (NTIS)

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 Fr...

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

1992-01-01

129

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

130

Effect of fermentation conditions on the production of citric acid from cheese whey by Aspergillus niger  

Microsoft Academic Search

The effect of pH value, methanol, and salt concentration on the production of citric acid from cheese whey by two strains of Aspergillus niger i.e. CAIM 111 and CAIM 167, was investigated. Lactose concentration, utilized lactose, citric acid concentration, conversion coefficient of lactose to citric acid, and mycelial dry weight were measured during the fermentation process. The maximum citric acid

Y. A. El-Samragy; M. A. Khorshid; M. I. Foda; A. E. Shehata

1996-01-01

131

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

EPA Science Inventory

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

132

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

133

Solid-state fermentation for the synthesis of citric acid by Aspergillus niger  

Microsoft Academic Search

Solid-state fermentation was carried out to evaluate three different agro-industrial wastes, sugar cane bagasse, coffee husk and cassava bagasse for their efficiency in production of citric acid by a culture of Aspergillus niger. Cassava bagasse best supported the mould's growth, giving the highest yield of citric acid among the tested substrates. Results showed the fungal strain had good adaptation to

Luciana P. S Vandenberghe; Carlos R Soccol; Ashok Pandey; J.-M Lebeault

2000-01-01

134

Pseudoepidemic of Aspergillus niger Infections Traced to Specimen Contamination in the Microbiology Laboratory  

PubMed Central

We report a pseudo-outbreak of Aspergillus niger that followed building construction in our clinical microbiology laboratory. Because outbreaks of invasive aspergillosis have been linked to hospital construction, strategies to minimize dust in patient care areas are common practice. We illustrate that the impact of false-positive cultures on patient care should compel laboratories to prevent specimen contamination during construction.

Laurel, Valerie L.; Meier, Patricia A.; Astorga, Alicia; Dolan, Donna; Brockett, Royce; Rinaldi, Michael G.

1999-01-01

135

Aspergillus niger DLFCC-90 Rhamnoside Hydrolase, a New Type of Flavonoid Glycoside Hydrolase  

PubMed Central

A novel rutin-?-l-rhamnosidase hydrolyzing ?-l-rhamnoside of rutin, naringin, and hesperidin was purified and characterized from Aspergillus niger DLFCC-90, and the gene encoding this enzyme, which is highly homologous to the ?-amylase gene, was cloned and expressed in Pichia pastoris GS115. The novel enzyme was classified in glycoside-hydrolase (GH) family 13.

Liu, Tingqiang; Zhang, Chunzhi; Lu, Mingchun; Piao, Yongzhe; Ohba, Masashi; Tang, Minqian; Yuan, Xiaodong; Wei, Shenghua; Wang, Kan; Ma, Anzhou; Feng, Xue; Qin, Siqing; Mukai, Chisato; Tsuji, Akira

2012-01-01

136

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 Brandăo

2000-01-01

137

Disseminated Aspergillosis due to Aspergillus niger in Immunocompetent Patient: A Case Report  

PubMed Central

Invasive aspergillosis is a major cause of morbidity and mortality in immunocompromised patients. Many cases of pulmonary, cutaneous, cerebral, and paranasal sinus aspergillosis in immunocompetent patient were defined in literature but disseminated aspergillosis is very rare. Here we present an immunocompetent case with extrapulmonary disseminated aspergillosis due to Aspergillus niger, totally recovered after effective antifungal treatment with voriconazole.

Ergene, Ulku; Akcali, Zeynep; Ozbalci, Demircan; Nese, Nalan; Senol, Sebnem

2013-01-01

138

Colonization of rye green manure and peanut fruit debris by Aspergillus falvus and Aspergillus niger group in field soils.  

PubMed Central

Aspergillus flavus and Aspergillus niger group colonization of deep-plowed, decomposing rye green manure cover crops in peanut field soils was studied in four fields during 1972 and 1973; colonization of decomposing peanut fruits was studied in 1972 in two fields. A. flavus colonization of rye and peanut fruits was greater in soils of heavy texture, and an A. flavus population as high as 165 propagules per g of soil was observed in soil adjacent to rye, whereas A. flavus populations in soils not associated with rye were 18 propagules per g of soil or lower. Highest A. flavus populations in soil adjacent to decomposing peanut fruits were usually comparable to populations associated with rye. Little decomposing rye or peanut fruit colonization was generally observed by the A. flavus competitor, A. niger group. A. flavus may maintain or increase its inoculum potential by colonization of these and other moribund plant tissues.

Griffin, G J; Garren, K H

1976-01-01

139

Oxalic acid production by Aspergillus niger: an oxalate-non-producing mutant produces citric acid at pH 5 and in the presence of manganese.  

PubMed

The external pH appeared to be the main factor governing oxalic acid production by Aspergillus niger. A glucose-oxidase-negative mutant produced substantial amounts of oxalic acid as long as the pH of the culture was 3 or higher. When pH was decreased below 2, no oxalic acid was formed. The activity of oxaloacetate acetylhydrolase (OAH), the enzyme believed to be responsible for oxalate formation in A. niger, correlated with oxalate production. OAH was purified from A. niger and characterized. OAH cleaves oxaloacetate to oxalate and acetate, but A. niger never accumulated any acetate in the culture broth. Since an A. niger acuA mutant, which lacks acetyl-CoA synthase, did produce some acetate, wild-type A. niger is apparently able to catabolize acetate sufficiently fast to prevent its production. An A. niger mutant, prtF28, previously isolated in a screen for strains deficient in extracellular protease expression, was shown here to be oxalate non-producing. The prtF28 mutant lacked OAH, implying that OAH is the only enzyme involved in oxalate production in A. niger. In a traditional citric acid fermentation low pH and absence of Mn2+ are prerequisites. Remarkably, a strain lacking both glucose oxidase (goxC) and OAH (prtF) produced citric acid from sugar substrates in a regular synthetic medium at pH 5 and under these conditions production was completely insensitive to Mn2+. PMID:10517610

Ruijter, G J; van de Vondervoort, P J; Visser, J

1999-09-01

140

Correlation of mycotoxin fumonisin B2 production and presence of the fumonisin biosynthetic gene fum8 in Aspergillus niger from grape.  

PubMed

Aspergillus niger is a significant component of the fungal community on grapes. The mycotoxin fumonisin B2 (FB2) was recently detected in grape must and wine as well as in cultures of some A. niger strains isolated from grapes and raisins. This study examined 48 strains of Aspergillus section Nigri for the presence of the fumonisin biosynthetic gene fum8 in relation to FB2 production. The fum8 gene was detected in only 11 A. niger strains, 9 of which also produced FB2. Maximum parsimony analysis based on the calmodulin gene sequence indicated that the presence/absence of fum8 is not correlated with the phylogenetic relationship of the isolates. This is the first report correlating the presence of a fumonisin biosynthetic gene with fumonisin production in A. niger from an important food crop. The results suggest that the absence of FB2 production in grape isolates of A. niger can result from the absence of at least one gene essential for production. PMID:20666454

Susca, Antonia; Proctor, Robert H; Mulč, Giuseppina; Stea, Gaetano; Ritieni, Alberto; Logrieco, Antonio; Moretti, Antonio

2010-08-25

141

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

PubMed Central

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

Shivanna, Gunashree B.; Venkateswaran, Govindarajulu

2014-01-01

142

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

PubMed

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

Shivanna, Gunashree B; Venkateswaran, Govindarajulu

2014-01-01

143

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

PubMed

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

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

2014-06-01

144

Incidence of fumonisin B2 production within Aspergillus section Nigri populations isolated from California raisins.  

PubMed

Fungi belonging to Aspergillus section Nigri occur frequently and in high populations on grapes. Species within this section include Aspergillus niger, A. tubingensis, and A. carbonarius, and they are potential sources for mycotoxins including ochratoxin A and fumonisin B(2) (FB(2)) in grapes and grape products. Aspergillus section Nigri strains were isolated from California raisins to examine the frequency and extent of FB(2) production. Of 392 strains isolated, 197 strains were identified as A. niger, 131 of which produced FB(2). These strains produced from 1.2 to 27 ?g/ml FB(2) in culture. PCR amplification of fum1 and fum19 gene fragments showed that all FB(2)-producing strains and nearly all nonproducing strains of A. niger contain these genes. An additional 175 strains were identified as A. tubingensis, none of which produced FB(2). PCR with fum1 and fum19 primers amplified gene fragments of 14 and 25% of A. tubingensis strains, respectively, suggesting that putative orthologs of A. niger fumonisin biosynthetic genes might occur in A. tubingensis. These results indicate that FB(2) production is common among field isolates of A. niger and suggest that the potential for FB(2) contamination of California raisins should be addressed further. PMID:21477486

Palumbo, Jeffrey D; O'Keeffe, Teresa L; McGarvey, Jeffery A

2011-04-01

145

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

2010-11-01

146

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

PubMed

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

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

2009-08-01

147

The cloning and sequencing of the genes encoding phytase (phy) and pH 2.5-optimum acid phosphatase (aph) from Aspergillus niger var. awamori.  

PubMed

The genes encoding phytase (EC 3.1.3.8) and pH 2.5-optimum acid phosphatase (EC 3.1.3.2) have been cloned and sequenced from Aspergillus niger var. awamori. The translated nucleotide sequences yielded polypeptides of 467 and 479 amino acids (aa) for phytase and acid phosphatase, respectively. The genes were isolated using oligodeoxyribonucleotide probes based on the aa sequences of the purified proteins. Recombinant A. niger var. awamori strains carrying additional copies of the gene sequences demonstrated elevated enzyme activities. PMID:8224894

Piddington, C S; Houston, C S; Paloheimo, M; Cantrell, M; Miettinen-Oinonen, A; Nevalainen, H; Rambosek, J

1993-10-29

148

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

PubMed

Aspergillus niger and Aspergillus carbonarius are two species in the Aspergillus section Nigri (black-spored aspergilli) frequently associated with peanut (Arachis hypogea), maize (Zea mays), and other plants as pathogens. These infections are symptomless and as such are major concerns since some black aspergilli produce important mycotoxins, ochratoxins A, and the fumonisins. To facilitate the study of the black aspergilli-maize interactions with maize during the early stages of infections, we developed a method that used the enhanced yellow fluorescent protein (eYFP) and the monomeric red fluorescent protein (mRFP1) to transform A. niger and A. carbonarius, respectively. The results were constitutive expressions of the fluorescent genes that were stable in the cytoplasms of hyphae and conidia under natural environmental conditions. The hyphal in planta distribution in 21-day-old seedlings of maize were similar wild type and transformants of A. niger and A. carbonarius. The in planta studies indicated that both wild type and transformants internally colonized leaf, stem and root tissues of maize seedlings, without any visible disease symptoms. Yellow and red fluorescent strains were capable of invading epidermal cells of maize roots intercellularly within the first 3 days after inoculation, but intracellular hyphal growth was more evident after 7 days of inoculation. We also tested the capacity of fluorescent transformants to produce ochratoxin A and the results with A. carbonarius showed that this transgenic strain produced similar concentrations of this secondary metabolite. This is the first report on the in planta expression of fluorescent proteins that should be useful to study the internal plant colonization patterns of two ochratoxigenic species in the Aspergillus section Nigri. PMID:23899775

Palencia, Edwin Rene; Glenn, Anthony Elbie; Hinton, Dorothy Mae; Bacon, Charles Wilson

2013-09-01

149

Citric acid production by Aspergillus niger immobilized on cellulose microfibrils: influence of morphology and fermenter conditions on productivity  

Microsoft Academic Search

Continuous and batch production of citric acid from sucrose has been investigated using Aspergillus niger NCIM 588. Mycelia of A. niger grown on cellulose microfibril forms a uniform and thin mycelial proliferation under controlled conditions of cultivation rich in oxygen. In the fed batch mode using a recycle reactor, the DO of the system was maintained at 20 mg l?1

N. V Sankpal; A. P Joshi; B. D Kulkarni

2001-01-01

150

Effect of fermentation conditions on the production of citric acid from cheese whey by Aspergillus niger.  

PubMed

The effect of pH value, methanol, and salt concentration on the production of citric acid from cheese whey by two strains of Aspergillus niger, i.e. CAIM 111 and CAIM 167, was investigated. Lactose concentration, utilized lactose, citric acid concentration, conversion coefficient of lactose to citric acid, and mycelial dry weight were measured during the fermentation process. The maximum citric acid concentration (1.06 and 0.82 g/l), and conversion coefficient (5.58 and 7.45%) were obtained at pH 3.5 after 9 days of fermentation for A. niger CAIM 111 and A. niger CAIM 167, respectively. The presence of 4% (v/v) methanol in the fermentation medium increased the amount of citric acid produced by A. niger CAIM 111 and A. niger CAIM 167 by 23% and 18%, respectively. Both strains showed a high ability to utilize lactose for the production of citric acid when grown in the presence of 10% (w/v) salt. The conversion coefficient of lactose to citric acid was 28.24% for A. niger CAIM 111 and 25.60% for A. niger CAIM 167 when the fermentation medium had a 10% (w/v) level of salt. The cumulative effect of fermentation medium pH (3.5), methanol concentration (4%, v/v) and salt concentration (10%, w/v) during the fermentation process of whey did not enhance the production of citric acid by A. niger CAIM 111, while it did increase the production of citric acid by A. niger CAIM 167 by about 4-fold. PMID:8796442

el-Samragy, Y A; Khorshid, M A; Foda, M I; Shehata, A E

1996-04-01

151

Effects of physicochemical parameters on the production of phenolic acids from palm oil mill effluent under liquid-state fermentation by Aspergillus niger IBS-103ZA  

Microsoft Academic Search

The present investigation is an effort to develop an environmentally friendly and cost-effective liquid-state fermentation process by introducing a new locally isolated fungal strain of Aspergillus niger (IBS-103ZA) for the production of phenolics from a new source, palm oil mill effluent (POME). Sucrose, manganese sulphate (MnSO4) and temperature were identified as the most significant variables in improving phenolics production. Optimisation

Parveen Jamal; Zulkarnain Mohamed Idris

2011-01-01

152

Autophagy promotes survival in aging submerged cultures of the filamentous fungus Aspergillus niger.  

PubMed

Autophagy is a well-conserved catabolic process constitutively active in eukaryotes that is involved in maintaining cellular homeostasis by the targeting of cytoplasmic content and organelles to vacuoles. Autophagy is strongly induced by the limitation of nutrients including carbon, nitrogen, and oxygen and is clearly associated with cell death. It has been demonstrated that the accumulation of empty hyphal compartments and cryptic growth in carbon-starved submerged cultures of the filamentous fungus Aspergillus niger is accompanied by a joint transcriptional induction of autophagy genes. This study examines the role of autophagy by deleting the atg1, atg8, and atg17 orthologs in A. niger and phenotypically analyzing the deletion mutants in surface and submerged cultures. The results indicate that atg1 and atg8 are essential for efficient autophagy, whereas deletion of atg17 has little to no effect on autophagy in A. niger. Depending on the kind of oxidative stress confronted with, autophagy deficiency renders A. niger either more resistant (menadione) or more sensitive (H2O2) to oxidative stress. Fluorescence microscopy showed that mitochondrial turnover upon carbon depletion in submerged cultures is severely blocked in autophagy-impaired A. niger mutants. Furthermore, automated image analysis demonstrated that autophagy promotes survival in maintained carbon-starved cultures of A. niger. Taken together, the results suggest that besides its function in nutrient recycling, autophagy plays important roles in physiological adaptation by organelle turnover and protection against cell death upon carbon depletion in submerged cultures. PMID:23700238

Nitsche, Benjamin M; Burggraaf-van Welzen, Anne-Marie; Lamers, Gerda; Meyer, Vera; Ram, Arthur F J

2013-09-01

153

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

PubMed

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

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

1990-04-16

154

Semi-solid-state fermentation of Eicchornia crassipes biomass as lignocellulosic biopolymer for cellulase and ?-glucosidase production by cocultivation of Aspergillus niger RK3 and Trichoderma reesei MTCC164  

Microsoft Academic Search

An aquatic weed biomass, Eicchornia crassipes, present in abundance and leading to a threatening level of water pollution was used as substrate for cellulase and ?-glucosidase\\u000a production using wild-type strain Aspergillus niger RK3 that was isolated from decomposing substrate. Alkali treatment of the biomass (10%) resulted in a 60–66% increase in\\u000a endoglucanase, exoglucanase, and ?-glucosidase production by the A. niger

Raj Kumar; R. P. Singh

2001-01-01

155

Medium optimization by orthogonal array designs for urease production by Aspergillus niger PTCC5011  

Microsoft Academic Search

This paper describes medium optimization for urease production by Aspergillus niger PTCC5011 by one-factor-at-a-time and orthogonal array design methods. The one-factor-at-a-time method was used to study the effects of carbon and nitrogen sources on urease production. Among various carbon and nitrogen sources used, sucrose and yeast extract were the most suitable for urease production, respectively. Subsequently, the concentration of sucrose,

M. R. Bakhtiari; M. G. Faezi; M. Fallahpour; A. Noohi; N. Moazami; Z. Amidi

2006-01-01

156

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

157

Accelerated Death Kinetics of Aspergillus niger Spores under High-Pressure Carbonation  

Microsoft Academic Search

The death kinetics of Aspergillus niger spores under high-pressure carbonation were investigated with respect to the concentration of dissolved CO2 (dCO2) and treatment temperature. All of the inactivation followed first-order death kinetics. The D value (decimal reduction time, or the time required for a 1-log-cycle reduction in the microbial population) in the saline carbonated at 10 MPa was 0.16 min

M. Shimoda; H. Kago; N. Kojima; M. Miyake; Y. Osajima; I. Hayakawa

2002-01-01

158

Mixed culture solid substrate fermentation of Trichoderma reesei with Aspergillus niger on sugar cane bagasse  

Microsoft Academic Search

Trichoderma reesei LM-UC4, the parent strain, and its hypercellulolytic mutant LM-UC4E1 were co-cultured with Aspergillus niger ATCC 10864 in solid substrate fermentation on alkali-treated sugar cane for cellulolytic enzyme production. Bagasse was supplemented with either soymeal or with ammonium sulfate and urea, and fermented at 80% moisture content and 30°C. Mixed culturing produced better results with the inorganic supplement. The

Marcel Gutierrez-Correa; Leticia Portal; Patricia Moreno; Robert P. Tengerdy

1999-01-01

159

The role of the tricarboxylic acid cycle in citric acid accumulation by Aspergillus niger  

Microsoft Academic Search

Determinations of the momentary levels of various intermediates related to the activity of the tricarboxylic acid cycle have been made during citric acid production in high-accumulating (manganese deficient) and lowaccumulating (manganese supplemented) mycelia of Aspergillus niger. During the growth period the levels of almost all TCA cycle acids, with the exception of 2-oxo-acids, were unusually high; during the induction phase

C. P. Kubicek; M. Röhr

1978-01-01

160

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

161

Functional expression of amine oxidase from Aspergillus niger (AO-I) in Saccharomyces cerevisiae  

Microsoft Academic Search

The aim of this work was to prepare recombinant amine oxidase from Aspergillus niger after overexpressing in yeast. The yeast expression vector pDR197 that includes a constitutive PMA1 promoter was used for\\u000a the expression in Saccharomyces cerevisiae. Recombinant amine oxidase was extracted from the growth medium of the yeast, purified to homogeneity and identified by activity\\u000a assay and MALDI-TOF peptide

Kate?ina Kola?íková; Petr Galuszka; Iva Sedlá?ová; Marek Šebela; Ivo Frébort

2009-01-01

162

Partial purification and characterization of a polyphenol esterase from Aspergillus niger  

Microsoft Academic Search

Crude pectinase extract (FI), obtained from Aspergillus niger, was partially purified by ammonium sulphate precipitation at saturation of 0–20% (FIIa), 20–80% (FIIb) and 80–100% (FIIc). While all precipitated fractions exhibited pectin methyl esterase (PME), ?-1,3-glucanase, polyphenol esterase (PPE), polygalacturonase (PG) and ?-galactosidase activities, fraction FIIa contained the majority of PME and ?-1,3-glucanase activities. However, fraction FIIc contained the highest PPE,

W. Madani; S. Kermasha; M. Goetghebeur; M. Tse

1997-01-01

163

Expression of an Aspergillus niger Phytase Gene (phyA )i n Saccharomyces cerevisiae  

Microsoft Academic Search

Phytase improves the bioavailability of phytate phosphorus in plant foods to humans and animals and reduces phosphorus pollution of animal waste. Our objectives were to express an Aspergillus niger phytase gene (phyA )i nSaccharomyces cerevisiae and to determine the effects of glycosylation on the phytase's activity and thermostability. A 1.4-kb DNA fragment containing the coding region of the phyA gene

YANMING HAN; DAVID B. WILSON; XIN GEN LEI

1999-01-01

164

Rock phosphate solubilization by Aspergillus niger grown on sugar-beet waste medium  

Microsoft Academic Search

Solubilization of rock phosphate by Aspergillus niger was studied in solid-state fermentation on sugar-beet waste. This combination was selected after testing three agroindustrial waste materials, namely rice hulls, sugar-beet waste and alperujo. Sugar-beet waste was the best substrate for fungal growth with 69% mineralization, followed by rice hulls and alperujo. The fungus was successfully cultivated on sugar-beet waste supplemented with

N. Vassilev; M. T. Baca; M. Vassileva; I. Franco; R. Azcon

1995-01-01

165

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

166

Citric and gluconic acid production from fig by Aspergillus niger using solid-state fermentation  

Microsoft Academic Search

  The production of citric and gluconic acids from fig by Aspergillus niger ATCC 10577 in solid-state fermentation was investigated. The maximal citric and gluconic acids concentration (64 and 490\\u000a g\\/kg dry figs, respectively), citric acid yield (8%), and gluconic acid yield (63%) were obtained at a moisture level of 75%,\\u000a initial pH 7.0, temperature 30°C, and fermentation time in 15

T Roukas

2000-01-01

167

Nutritional Status of Cassava Peels and Root Sieviate Biodegraded With Aspergillus niger  

Microsoft Academic Search

2 Abstract: The ability of Aspergillus niger to improve the nutritional status of Cassava Root Sieviate (CRS) and peels was assessed for ten days through biodegradation. The biodegradation within this time had several effects on the proximate content of the substrates. The protein content of CRS recorded for 0, 5 and 10 days were 2.09, 5.21 and 7.34% while these

F. A. Aderemi; F. C. Nworgu

168

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. Cabańes

2006-01-01

169

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. Cabańes

2006-01-01

170

Purification and Characterization of a Lipase from Aspergillus niger F044  

Microsoft Academic Search

A lipase from Aspergillus niger F044 was purified to homogeneity using ammonium sulfate precipitation, dialysis, DEAE-Sepharose Fast Flow anion exchange chromatography, and Sephadex G-75 gel filtration chromatography. This purification protocol resulted in a 73.71-fold purification of lipase with 33.99 % final yield, and the relative molecular weight of the lipase were determined to be approximately 35-40 kD using SDS-PAGE. The

Zheng-Yu SHU; Jiang-Ke YANG; Yun-Jun YAN

2007-01-01

171

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

172

Enzymatic Enhancement of Citric Acid Production by Aspergillus niger From Corn Cobs  

Microsoft Academic Search

Rapidase Pomaliq (Gist-Brocades), a commercial apple juice processing enzyme preparation, was used to enhance the production of citric acid from corn cobs by Aspergillus niger (NRRL, 2001). Combined treatments of corn cobs with dilute NaOH and the commercial enzyme significantly increased the yield of citric acid. Under favorable conditions (pretreated with 0.1 N NaOH, followed by 72 h of fermentation

Y. D. Hang; E. E. Woodams

2001-01-01

173

Corn Husks: A Potential Substrate for Production of Citric Acid by Aspergillus niger  

Microsoft Academic Search

Corn husks could serve as a potential substrate for the production of citric acid by Aspergillus niger NRRL 2001. Combined treatments of corn husks with dilute NaOH and Rapidase Pomaliq (a commercial apple juice processing enzyme preparation) significantly enhanced the yield of citric acid. Under favourable conditions (pretreated with 0.5 mol\\/L NaOH, followed by 120 h of fermentation at 30°C

Y. D Hang; E. E Woodams

2000-01-01

174

Immobilization of Aspergillus niger NRC 107 xylanase and ?-xylosidase, and properties of the immobilized enzymes  

Microsoft Academic Search

Aspergillus niger NRC 107 xylanase and ?-xylosidase were immobilized on various carriers by different methods of immobilization, including\\u000a physical adsorption, covalant binding, ionic binding, and entrapment. The immobilized enzymes were prepared by physical adsorption\\u000a on tannin-chitosan, ionic binding onto Dowex-50W, covalent binding on chitosan beads through glutaraldehyde, and entrapment\\u000a in polyacrylamide had the highest activities. In most cases, the optimum

Mohamed A. Abdel-Naby

1993-01-01

175

Optimization of enantioselective resolution of racemic ibuprofen by native lipase from Aspergillus niger  

Microsoft Academic Search

Resolution of (R,S)-ibuprofen (2-(4-isobutylphenyl)propionic acid) enantiomers by esterification reaction with 1-propanol in different organic solvents was studied using native Aspergillus niger lipase. The main variables controlling the process (enzyme concentration and 1-propanol:ibuprofen molar ratio) have been optimized using response surface methodology based on a five-level, two-variable central composite rotatable design, in which the selected objective function was enantioselectivity. This enzyme

Patrícia de O. Carvalho; Fabiano J. Contesini; Renato Bizaco; Silvana Ap. Calafatti; Gabriela A. Macedo

2006-01-01

176

Bioleaching of spent refinery processing catalyst using Aspergillus niger with high-yield oxalic acid  

Microsoft Academic Search

A spent refinery processing catalyst was physically and chemically characterized, and subjected to one-step and two-step bioleaching processes using Aspergillus niger. During bioleaching of the spent catalysts of various particle sizes (“as received”, 100–150?m, <37?m, and xŻ=2.97 (average) ?m) and pulp densities, the biomass dry weight and pH were determined. The corresponding leach liquor was analysed for excreted organic acids

Deenan Santhiya; Yen-Peng Ting

2005-01-01

177

Production of gluconic acid by Aspergillus niger immobilized on polyurethane foam  

Microsoft Academic Search

Production of gluconic acid by cells of Aspergillus niger immobilized on polyurethane foam was studied in repeated-batch shake-flask and bubble-column fermentations. For passive immobilization, various amounts of polyurethane foam and spore suspension were tested in order to obtain a suitable combination for optimal concentration of immobilized biomass. Immobilized cells were sucessfully reused with higher levels of product formation being maintained

Nikolay B. Vassilev; Maria Ch. Vassileva; Dimitrinka I. Spassova

1993-01-01

178

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

PubMed Central

Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of Pi and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14CO2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this was oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.

Kubicek, C P; Schreferl-Kunar, G; Wohrer, W; Rohr, M

1988-01-01

179

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

PubMed

Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of Pi and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14CO2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this was oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle. PMID:3132096

Kubicek, C P; Schreferl-Kunar, G; Wöhrer, W; Röhr, M

1988-03-01

180

Functional expression of amine oxidase from Aspergillus niger (AO-I) in Saccharomyces cerevisiae.  

PubMed

The aim of this work was to prepare recombinant amine oxidase from Aspergillus niger after overexpressing in yeast. The yeast expression vector pDR197 that includes a constitutive PMA1 promoter was used for the expression in Saccharomyces cerevisiae. Recombinant amine oxidase was extracted from the growth medium of the yeast, purified to homogeneity and identified by activity assay and MALDI-TOF peptide mass fingerprinting. Similarity search in the newly published A. niger genome identified six genes coding for copper amine oxidase, two of them corresponding to the previously described enzymes AO-I a methylamine oxidase and three other genes coding for FAD amine oxidases. Thus, A. niger possesses an enormous metabolic gear to grow on amine compounds and thus support its saprophytic lifestyle. PMID:17899443

Kolaríková, Katerina; Galuszka, Petr; Sedlárová, Iva; Sebela, Marek; Frébort, Ivo

2009-01-01

181

Kinetic modeling for the biosorption of copper by pretreated Aspergillus niger biomass.  

PubMed

In this present work, a kinetic model for biosorption of copper was developed considering the possibility of different forms of functional groups being present on the surface of the biomass prepared from Aspergillus niger. Results showed that metal uptake by A. niger was a mass transfer driven process, requiring only 30min to achieve 70% adsorption efficiency. Copper sorption by A. niger was influenced by the biomass dose, initial metal ion concentration, and pH of the solution. The Langmuir and Freundlich adsorption isotherms were used to describe the behavior of the system at different pH. The retention capacity of the biomass was determined at pH 6.0 to be equal to 23.62mg/g of biomass. The pretreatment with formalin improved the uptake of metal ion. PMID:16996263

Mukhopadhyay, Mausumi; Noronha, S B; Suraishkumar, G K

2007-07-01

182

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

183

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

PubMed

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 better culture medium than CYA for OTA production. In this medium, OTA was produced from pH 2 or 3 to 10 depending on the strain. The results show the ability of A. niger aggregate strains not only to grow, but also to produce OTA over a wide pH range. The results will lead to a better understanding of the role of A. niger aggregate strains in the OTA contamination of several food commodities. PMID:16766460

Esteban, A; Abarca, M L; Bragulat, M R; Cabańes, F J

2006-06-01

184

The Effect of organic nitrogen sources on recombinant glucoamylase production by Aspergillus niger in chemostat culture.  

PubMed

Aspergillus niger B1, a recombinant strain carrying 20 extra copies of the native glucoamylase gene, was grown in glucose-limited chemostat cultures supplemented with various organic nitrogen sources (dilution rate 0.12 +/- 0.01 h(-1), pH 5.4). In cultures supplemented with l-alanine, l-methionine, casamino acids, or peptone, specific glucoamylase (GAM) production rapidly decreased to less than 20% of the initial level. Reducing the pH of the culture to 4.0 resulted in stable GAM production for up to 400 h. Morphological mutants (a light brown and a dark brown mutant) appeared in each fermentation and generally displaced B1. Light brown mutants had higher selection coefficients relative to B1 than dark brown mutants and became the dominant strain in all fermentations except those maintained at pH 4.0. Several mutants isolated from these cultures had reduced ability to produce GAM in batch culture, although few had lost copies of the glaA gene. Some mutants had methylated DNA. PMID:11170742

Swift, R J; Karandikar, A; Griffen, A M; Punt, P J; van den Hondel, C A; Robson, G D; Trinci, A P; Wiebe, M G

2000-11-01

185

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

186

Enantioselective behavior of lipases from Aspergillus niger immobilized in different supports.  

PubMed

Considering the extraordinary microbial diversity and importance of fungi as enzyme producers, the search for new biocatalysts with special characteristics and possible applications in biocatalysis is of great interest. Here, we report the performance in the resolution of racemic ibuprofen of a native enantioselective lipase from Aspergillus niger, free and immobilized in five types of support (Accurel EP-100, Amberlite MB-1, Celite, Montmorillonite K10 and Silica gel). Amberlite MB-1 was found to be the best support, with a conversion of 38.2%, enantiomeric excess of 50.7% and enantiomeric ratio (E value) of 19 in 72 h of reaction. After a thorough optimization of several parameters, the E value of the immobilized Aspergillus niger lipase was increased (E = 23) in a shorter reaction period (48 h) at 35 degrees C. Moreover, the immobilized Aspergillus niger lipase maintained an esterification activity of at least 80% after 8 months of storage at 4 degrees C and could be reused at least six times. PMID:19390883

da Silva, Vania Castriani Fernandes; Contesini, Fabiano Jares; de Oliveira Carvalho, Patrícia

2009-07-01

187

Molecular cloning and characterization of the fructooligosaccharide-producing beta-fructofuranosidase gene from Aspergillus niger ATCC 20611.  

PubMed

The fopA gene encoding a fructooligosaccharide-producing beta-fructofuranosidase was isolated from Aspergillus niger ATCC 20611. The primary structure deduced from the nucleotide sequence showed considerable similarity to those of two other beta-fructofuranosidases from A. niger, but the fopA gene product had several amino acid insertions and an extra C-terminal polypeptide consisting of 38 amino acids that could not be found in the two others. We could successfully express the fopA gene in S. cerevisiae and the fopA gene product obtained from the culture supernatant of the S. cerevisiae transformant had similar characteristics to the beta-fructofuranosidase purified from A. niger ATCC 20611. However, we could not detect any beta-fructofuranosidase activity in either the culture supernatant or cell lysate when the C-terminal truncated fopA gene product by 38 amino acids was used to transform S. cerevisiae. In western analysis of those samples, there was no protein product that is cross-reacted with anti-beta-fructofuranosidase antibody. These results suggested that the C-terminal region of the fopA gene product consisting of 38 amino acids was essential for the enzyme production. PMID:11388451

Yanai, K; Nakane, A; Kawate, A; Hirayama, M

2001-04-01

188

Gluconate formation and polyol metabolism in Aspergillus niger  

Microsoft Academic Search

The capacity of A.niger to accumulate metabolites is remarkable. Under all conditions polyols accumulate in the cell and when mycelium in later developmental stages is considered, depending on the carbon source, aeration and external pH, polyols and\\/or organic acids can be formed in a very efficient way. The aim of this thesis was to obtain a better understanding of the

C. F. B. Witteveen

1993-01-01

189

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

190

Pectinolytic activity of revertants of auxotrophic strains of Aspergillus niger.  

PubMed

From conidia of 4 different auxotrophic A. niger strains 400 spontaneous revertants (100 from each strain) were obtained, and in one case additionally 100 revertants induced by mutagens (UV+NTG). The revertants showed a considerable differentiation with regard to the total pectinolytic activity. Its highest increase occurred in revertants originating from auxotrophs greatly predisposed to synthesize pectinases. In the case of revertants induced by mutagenes an increase in the frequency of their formation was observed, as well as an increased participation of revertants with higher pectinolytic activity compared to both their initial auxotrophic and prototrophic strain. PMID:2442973

Fiedurek, J; Ilczuk, Z

1987-01-01

191

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

192

Glucoamylase::green fluorescent protein fusions to monitor protein secretion in Aspergillus niger.  

PubMed

A glucoamylase::green fluorescent protein fusion (GLA::sGFP) was constructed which allows the green fluorescent protein to be used as an in vivo reporter of protein secretion in Aspergillus niger. Two secretory fusions were designed for secretion of GLA::sGFP which employed slightly different lengths of the glucoamylase protein (GLA499 and GLA514). Expression of GLA::sGFP revealed that fluorescence was localized in the hyphal cell walls and septa, and that fluorescence was most intense at hyphal apices. Extracellular GLA::sGFP was detectable by Western blotting only in the supernatant of young cultures grown in soya milk medium. In older cultures, acidification of the medium and induction of proteases were probably responsible for the loss of extracellular and cell wall fluorescence and the inability to detect GLA::sGFP by Western analysis. A strain containing the GLA::sGFP construct was subjected to UV mutagenesis and survivors screened for mutations in the general secretory pathway. Three mutants were isolated that were unable to form a halo on either starch or gelatin medium. All three mutants grew poorly compared to the parental strain. Fluorescence microscopy revealed that for two of the mutants, GLA::sGFP accumulated intracellularly with no evidence of wall fluorescence, whereas for the third mutant, wall fluorescence was observed with no evidence of intracellular accumulation. These results indicate that the GLA::sGFP fusion constructs can be used as convenient fluorescent markers to study the dynamics of protein secretion in vivo and as a tool in the isolation of mutants in the general secretory pathway. PMID:10708380

Gordon, C L; Khalaj, V; Ram, A F; Archer, D B; Brookman, J L; Trinci, A P; Jeenes, D J; Doonan, J H; Wells, B; Punt, P J; van den Hondel, C A; Robson, G D

2000-02-01

193

Extracellular lipase of Aspergillus niger NRRL3; production, partial purification and properties.  

PubMed

Four strains of Aspergillus niger were screened for lipase production. Each was cultivated on four different media differing in their contents of mineral components and sources of carbon and nitrogen. Aspergillus niger NRRL3 produced maximal activity (325U/ml) when grown in 3% peptone, 0.05% MgSO(4).7H(2)O, 0.05% KCl, 0.2% K(2)HPO(4) and 1% olive oil:glucose (0.5:0.5). A. niger NRRL3 lipase was partially purified by ammonium sulphate precipitation. The majority of lipase activity (48%) was located in fraction IV precipitated at 50-60% of saturation with a 18-fold enzyme purification. The optimal pH of the partial purified lipase preparation for the hydrolysis of emulsified olive oil was 7.2 and the optimum temperature was 60°C. At 70°C, the enzyme retained more than 90% of its activity. Enzyme activity was inhibited by Hg(2+) and K(+), whereas Ca(2+) and Mn(2+) greatly stimulated its activity. Additionally, the formed lipase was stored for one month without any loss in the activity. PMID:23100754

Adham, Nehad Z; Ahmed, E M

2009-03-01

194

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

2013-08-01

195

D-Galactose uptake is nonfunctional in the conidiospores of Aspergillus niger.  

PubMed

The majority of black Aspergilli (Aspergillus section Nigri), including Aspergillus niger, as well as many other Ascomycetes fail to germinate on d-galactose as a sole carbon source. Here, we provide evidence that the ability of A. niger to transport D-galactose is growth stage dependent, being absent in the conidiospores but present in the mycelia. Despite earlier claims, we could identify galactokinase activity in growing cells and all genes of the Leloir pathway (responsible for channelling D-galactose into the EMP pathway) are well induced on D-galactose (and also on lactose, D-xylose and L-arabinose) in the mycelial stage. Expression of all Leloir pathway genes was also detectable in conidiospores, although galE (encoding a galactokinase) and galD (encoding a galactose-1-phosphate uridylyl transferase) were expressed poorly. These results suggest that the D-galactose-negative phenotype of A. niger conidiospores may be due to the lack of inducer uptake. PMID:22324294

Fekete, Erzsébet; de Vries, Ronald P; Seiboth, Bernhard; vanKuyk, Patricia A; Sándor, Erzsébet; Fekete, Eva; Metz, Benjamin; Kubicek, Christian P; Karaffa, Levente

2012-04-01

196

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

PubMed

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

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

2014-01-01

197

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

PubMed Central

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

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

2014-01-01

198

The Aspergillus niger annexin, anxC3.1 is constitutively expressed and is not essential for protein secretion.  

PubMed

An annexin, anxC3.1, was isolated and characterised from the industrially important filamentous fungus Aspergillus niger. anxC3.1 is a single copy gene encoding a 506 amino acid predicted protein which contains four annexin repeats. Disruption of the anxC3.1 gene did not lead to any visible changes in phenotype, nor in the levels of secreted protein, nor specifically in glucoamylase production, suggesting no major role in secretion. anxC3.1 expression was found to be unaltered under a variety of conditions such as increased secretion, altered nitrogen source, heat shock, and decreased Ca2+ levels, indicating that anxC3.1 is constitutively expressed. This is the first reported functional characterisation of a fungal annexin. PMID:15451115

Khalaj, Vahid; Hey, Peter; Smith, Lyndsay; Robson, Geoffrey D; Brookman, Jayne

2004-10-01

199

Removal of silver nanoparticles using live and heat shock Aspergillus niger cultures.  

PubMed

Silver nanoparticles (SNPs) are extensively used in many industrial and medical applications; however, the impact of their release in the environment is still considered an understudied field. In the present work, SNPs present in aqueous lab waste water (average size of 30 nm) were used to determine their impact on microflora if released in soil rhizosphere and sewage waste water. The results showed that 24 h incubation with different SNP concentrations resulted in a 2.6-fold decrease for soil rhizosphere microflora and 7.45-fold decrease for sewage waste water microflora, both at 24 ppm. Live and heat shock (50 and 70 °C) Aspergillus niger cultures were used to remove SNP waste, the results show 76.6, 81.74 and 90.8 % SNP removal, respectively after 3 h incubation. There was an increase in the log total bacterial count again after SNP removal by A. niger in the following order: live A. niger < 50 °C heat shock A. niger < 70 °C heat shock A. niger. The pH value decreased from 5.8 to 3.8 in the same order suggesting the production of an acid in the culture media. Scanning electron microscopy images showed agglomeration and/or complexation of SNP particles, in a micron size, in between the fungal mycelia, hence settling on and in between the mycelial network. The results suggest that silver was reduced again and agglomerated and/or chelated together in its oxidized form by an acid in A. niger media. More studies are recommended to determine the acid and the heat shock proteins to confirm the exact mode of action. PMID:24415500

Gomaa, Ola M

2014-06-01

200

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

201

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

PubMed

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

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

2011-02-28

202

Biological leaching of heavy metals from a contaminated soil by Aspergillus niger.  

PubMed

Bioleaching of heavy metals from a contaminated soil in an industrial area using metabolites, mainly weak organic acids, produced by a fungus Aspergillus niger was investigated. Batch experiments were performed to compare the leaching efficiencies of one-step and two-step processes and to determine the transformation of heavy metal chemical forms during the bioleaching process. After the one or two-step processes, the metal removals were compared using analysis of variance (ANOVA) and least-significance difference (LSD). A. niger exhibits a good potential in generating a variety of organic acids effective for metal solubilisation. Results showed that after the one-step process, maximum removals of 56%, 100%, 30% and 19% were achieved for copper, cadmium, lead and zinc, respectively. After the two-step process, highest removals of 97.5% Cu, 88.2% Cd, 26% Pb, and 14.5% Zn were obtained. Results of sequential extraction showed that organic acids produced by A. niger were effective in removing the exchangeable, carbonate, and Fe/Mn oxide fractions of Cu, Cd, Pb and Zn; and after both processes the metals remaining in the soil were mainly bound in stable fractions. Such a treatment procedure indicated that leaching of heavy metals from contaminated soil using A. niger has the potential for use in remediation of contaminated soils. PMID:19232463

Ren, Wan-Xia; Li, Pei-Jun; Geng, Yong; Li, Xiao-Jun

2009-08-15

203

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

PubMed Central

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

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

2013-01-01

204

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

PubMed

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 0.2 MPa (gauge pressure) of high pressure intensity, 30 min of low pressure duration and 20s of high pressure duration. Based on the optimized condition, the APP-SSF achieved the reasonable enzyme yield of 881 mU/g at 48 h, which was 58% more than that by static solid state fermentation (static SSF) at 72 h. By comparison of two fermentation methods in temperature, O(2) and CO(2) concentration, and respiration intensity, it was concluded that APP-SSF enhanced heat and mass transfer of fermentation system and strengthened the metabolism of microorganisms. The APP-SSF had a greatly positive effect on FAE production by A. niger, by enhancing mass and heat transfer and activating growth and metabolism. PMID:18929480

Zeng, W; Chen, H Z

2009-02-01

205

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

Microsoft Academic Search

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

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

2008-01-01

206

Methanol production is enhanced by expression of an Aspergillus niger pectin methylesterase in tobacco cells.  

PubMed

Tobacco suspension culture cell (Nicotiana tabacum, BY2) was transformed with an Aspergillus niger pectin methylesterase (PME; EC 3.1.1.11) cDNA under the control of cauliflower mosaic virus (CaMV) 35S promoter. The transformant indicated a significant rise of PME and the level of methanol in the transformant increased by 28.7% compared to the vector control transformant. This is the first report of methanol overproduction in plant cells by means of genetic engineering. PMID:14636709

Hasunuma, Tomohisa; Fukusaki, Ei-ichiro; Kobayashi, Akio

2003-12-01

207

Production of verbenol, a high valued food flavourant from a fusant strain of Aspergillus niger.  

PubMed

A hyperperformer for the production of verbenol was produced from the fusion of two improved strains of Aspergillus niger. A 2-deoxy glucose de-repressed mutant [high sporulation (50%), viability (80%) showing a conversion of 15.6% of initial alpha-pinene to verbenol in 6 h under the conditions used] was fused with another strain enriched with alpha-pinene (26.4% of alpha pinene converted to verbenol) to obtain a final verbenol conversion yield of 48.6% of initial alpha pinene. PMID:12759788

Vidya, C M; Agrawal, R

2003-09-01

208

Exopectinases produced by Aspergillus niger in solid-state and submerged fermentation: a comparative study  

Microsoft Academic Search

  Exopectinase production by Aspergillus niger was compared in submerged fermentation (SmF) and solid-state fermentation (SSF). SSF was carried out using polyurethane foam\\u000a (PUF) as the solid support. The purpose was to study the effect of sucrose addition (0 or 40 g\\/l) and water activity level\\u000a (A\\u000a w=0.99 or 0.96) on the level of enzyme activity induced by 15 g\\/l of

G Díaz-Godínez; J Soriano-Santos; C Augur; G Viniegra-González

2001-01-01

209

Induced reactive oxygen species improve enzyme production from Aspergillus niger cultivation.  

PubMed

Intracellular reactive oxygen species (iROS) induction by HOCl was used as a novel strategy to improve enzyme productivities in Aspergillus niger growing in a bioreactor. With induced iROS, the specific intracellular activities of alpha-amylase, protease, catalase, and glucose oxidase were increased by about 170%, 250%, 320%, and 260%, respectively. The optimum specific iROS level for achieving maximum cell concentration and enzyme production was about 15 mmol g cell-1. The type of iROS inducing the enzyme production was identified to be a derivative of the superoxide radical. PMID:12882014

Sahoo, Susmita; Rao, K Krishnamurthy; Suraishkumar, G K

2003-05-01

210

Gene overexpression and biochemical characterization of the biotechnologically relevant chlorogenic acid hydrolase from Aspergillus niger.  

PubMed

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 x 10(6) 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. PMID:17630312

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

2007-09-01

211

Terpenoid composition and antifungal activity of three commercially important essential oils against Aspergillus flavus and Aspergillus niger.  

PubMed

Hydro-distilled essential oils extracted from three commercially important aromatic plants were analysed by capillary gas chromatography-flame ionization detector and gas chromatography/quadrupole mass spectrometry and subjected to antifungal activity. Fifteen compounds, which accounted for 97.8% of Acorus calamus root oil composition have been identified. Besides the major constituent (Z)-asarone (81.1-92.4%), (Z)-methyl isoeugenol (1.8-2.1%), (Z)-isoelemicin (1.2-1.3%), (E)-asarone (1.0-2.6%), (E)-methyl isoeugenol (0.2-0.4%), (Z)-?-ocimene (0.2-0.4%), elemicin (0.2-0.3%), linalool (0.1-0.9%) and kessane (t-0.2%) were identified. Monoterpenes constituted the main fraction of Origanum vulgare essential oil attaining 90.5% of the total oil composition. p-Cymene (10.3%) was the major component of the monoterpene hydrocarbon fraction while thymol (53.2%) and carvacrol (3.9%) were the most abundant oxygenated monoterpenes among the 33 identified constituents. Cinnamomum tamala leaf oil contained (E)-cinnamaldehyde as the principal component. Quantitative variations in (Z)-cinnamaldehyde (5.8-7.1%), linalool (6.4-8.5%) and (E)-cinnamyl acetate (4.7-5.2%) were significant. The antifungal activity of the hydro-distilled essential oils of A. calamus, O. vulgare and C. tamala were evaluated against Aspergillus flavus and Aspergillus niger. Disc diffusion method was used for the determination of the inhibitory effect. O. vulgare essential oil exhibited the highest activity. Moreover, all three essential oils inhibit the growth of A. flavus and A. niger. PMID:21707253

Bisht, Deepa; Pal, Anirban; Chanotiya, C S; Mishra, Dhirendra; Pandey, K N

2011-12-01

212

Optimization of the parameters for decolourization by Aspergillus niger of anaerobically digested distillery spentwash pretreated with polyaluminium chloride.  

PubMed

Molasses spentwash from distilleries is characterized by high COD and colour. The fungal decolourization of anaerobically digested molasses spentwash requires significant dilution. In this study, decolourization by Aspergillus niger isolate IITB-V8 was performed on polyaluminium chloride (PAC) treated anaerobically digested spentwash without dilution of wastewater. Optimization of parameters was studied using statistical experimental designs. In the first step, Plackett-Burman design was used for screening the important parameters. Glucose was taken as the carbon source for the growth of A. niger. KH(2)PO(4) and pH were found to be the important factors affecting decolourization. In the second step, Box-Behnken design was used to determine the optimum level of each of the significant parameters. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the important factors to achieve maximum decolourization of 68.4% were 5.5 g/L Glucose, 1.2 g/L KH(2)PO(4) and 5 pH. The determination coefficient (R(2)) was 0.9973, which ensures adequate credibility of the model. The total decolourization obtained after fungal treatment was 86.8% which indicates fungal decolourization after pretreatment with PAC is a viable option for the treatment of digested molasses spentwash. PMID:20022424

Singh, S S; Dikshit, A K

2010-04-15

213

Molecular cloning and heterologous expression of the isopullulanase gene from Aspergillus niger A.T.C.C. 9642.  

PubMed Central

Isopullulanase (IPU) from Aspergillus niger A.T.C.C. (American Type Culture Collection) 9642 hydrolyses pullulan to isopanose. IPU is important for the production of isopanose and is used in the structural analysis of oligosaccharides with alpha-1,4 and alpha-1,6 glucosidic linkages. We have isolated the ipuA gene encoding IPU from the filamentous fungi A. niger A.T.C.C. 9642. The ipuA gene encodes an open reading frame of 1695 bp (564 amino acids). IPU contained a signal sequence of 19 amino acids, and the molecular mass of the mature form was calculated to be 59 kDa. IPU has no amino-acid-sequence similarity with the other pullulan-hydrolysing enzymes, which are pullulanase, neopullulanase and glucoamylase. However, IPU showed a high amino-acid-sequence similarity with dextranases from Penicillium minioluteum (61%) and Arthrobacter sp. (56%). When the ipuA gene was expressed in Aspergillus oryzae, the expressed protein (recombinant IPU) had IPU activity and was immunologically reactive with antibodies raised against native IPU. The substrate specificity, thermostability and pH profile of recombinant IPU were identical with those of the native enzyme, but recombinant IPU (90 kDa) was larger than the native enzyme (69-71 kDa). After deglycosylation with peptide-N-glycosidase F, the deglycosylated recombinant IPU had the same molecular mass as deglycosylated native enzyme (59 kDa). This result suggests that the carbohydrate chain of recombinant IPU differed from that of the native enzyme.

Aoki, H; Yopi; Sakano, Y

1997-01-01

214

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

215

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

216

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

217

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

218

beta-Galactosidase from Aspergillus niger in adult lactose malabsorption: a double-blind crossover study.  

PubMed

An assessment was made of the efficacy of a beta-galactosidase, obtained from Aspergillus niger and added to intact milk, in decreasing lactose malabsorption and intolerance. Sixteen adult patients with malabsorption and intolerance to this sugar were studied in a double-blind crossover study vs. placebo. A 5-hour hydrogen breath test was used to assess malabsorption of lactose contained in 400 ml milk. When compared with placebo, the addition of exogenous lactase to intact milk caused a statistically significant reduction in the maximum breath H2 concentration (P less than 0.01) and in the cumulative H2 excretion (P less than 0.005). In the same way, the cumulative index for gastrointestinal intolerance was significantly lower (P less than 0.005) after the ingestion of lactase-added milk. This study demonstrates that enzyme replacement therapy, with beta-galactosidases obtained from Aspergillus niger, is effective in decreasing lactose malabsorption and its consequent intolerance in adult subjects with lactase deficiency. PMID:1543816

Corazza, G R; Benati, G; Sorge, M; Strocchi, A; Calza, G; Gasbarrini, G

1992-02-01

219

A polyphasic approach to the identification of ochratoxin A-producing black Aspergillus isolates from vineyards in Sicily.  

PubMed

Aspergillus strains belonging to section Nigri isolated during a two year survey in eight Sicilian vineyards located on the slopes of Mount Etna (Sicily, Italy) were analysed analyzed in order to characterize species responsible for ochratoxin A (OTA) contamination of grapes. The polyphasic approach permitted analysis of biodiversity of Aspergillus isolates in relation to their morphology, ochratoxigenicity and genetic variability. We assessed OTA production by A. carbonarius, A. niger, A. tubingensis and A. japonicus using an enzyme-linked immunosorbent assay. A. carbonarius isolates were the strongest OTA producers. A subset of 66 representative strains was selected for further DNA-based characterization. PCR assays using species-specific primers discriminated between A. niger, A. carbonarius and A. japonicus on the basis of the target sequences for each species. The PCR-based methods matched morphological characterization in identifying all the black aspergilli (BA) isolates tested, whereas RFLP analysis with RsaI of isolates positive to PCRs with A. niger specific primers identified three A. tubingensis isolates. The identification of thirteen isolates was further confirmed by ITS analysis. By this method, each of the isolates was identified and assigned to an Aspergillus species. The fAFLP analysis of 40 isolates highlighted the power of this technique to discriminate different species and single strains, to verify the presence of mixed populations in the same vineyard, through homogeneous species clusters. No correlation was observed between the clusters and OTA production level or origin. PMID:18687497

Oliveri, C; Torta, L; Catara, V

2008-09-30

220

Heterologous expression of Trametes versicolor laccase in Pichia pastoris and Aspergillus niger.  

PubMed

Convenient expression systems for efficient heterologous production of different laccases are needed for their characterization and application. The laccase cDNAs lcc1 and lcc2 from Trametes versicolor were expressed in Pichia pastoris and Aspergillus niger under control of their respective glyceraldehyde-3-phosphate dehydrogenase promoters and with the native secretion signal directing catalytically active laccase to the medium. P. pastoris batch cultures in shake-flasks gave higher volumetric activity (1.3 U/L) and a better activity to biomass ratio with glucose than with glycerol or maltose as carbon source. Preliminary experiments with fed-batch cultures of P. pastoris in bioreactors yielded higher activity (2.8 U/L) than the shake-flask experiments, although the levels remained moderate and useful primarily for screening purposes. With A. niger, high levels of laccase (2700 U/L) were produced using a minimal medium containing sucrose and yeast extract. Recombinant laccase from A. niger harboring the lcc2 cDNA was purified to homogeneity and it was found to be a 70-kDa homogeneous enzyme with biochemical and catalytic properties similar to those of native T. versicolor laccase A. PMID:16915640

Bohlin, Christina; Jönsson, Leif J; Roth, Robyn; van Zyl, Willem H

2006-01-01

221

[Cloning and sequence analysis of the phytase phyA gene of Aspergillus niger N25].  

PubMed

The phyA encoding phytase of Aspergillus niger N25 was amplified by the polymerase chain reaction (PCR) with primers designed according to the sequences of the phyA in GenBank. The amplified fragment was cloned and sequenced. The results show that: the coding region is 1506 bp in size, includes a 102 bp intron, and encodes a peptide of 476 amino acid residues, in which there is a signal peptide with 19 amino acids and a mature peptide of 448 amino acids. Comparison of this sequence with the phyA of the natural A. niger NRRL3135 (GenBank Accession: M94550), the most highly secreting-phytase strain, shows that the nucleotide homology is as high as 96.746%, and the amino acid homology comes up to 97.64%. The phyA of A. niger N25 strain in this paper is appropriate to be used to construct the phytase gene-engineering bacteria. PMID:12561778

Wang, H; Wu, Q; Liu, S; Xie, J; Ma, M

2001-06-01

222

Glucoamylase starch-binding domain of Aspergillus niger B1: molecular cloning and functional characterization.  

PubMed Central

Carbohydrate-binding modules (CBMs) are protein domains located within a carbohydrate-active enzyme, with a discrete fold that can be separated from the catalytic domain. Starch-binding domains (SBDs) are CBMs that are usually found at the C-terminus in many amylolytic enzymes. The SBD from Aspergillus niger B1 (CMI CC 324262) was cloned and expressed in Escherichia coli as an independent domain and the recombinant protein was purified on starch. The A. niger B1 SBD was found to be similar to SBD from A. kawachii, A. niger var. awamori and A. shirusami (95-96% identity) and was classified as a member of the CBM family 20. Characterization of SBD binding to starch indicated that it is essentially irreversible and that its affinity to cationic or anionic starch, as well as to potato or corn starch, does not differ significantly. These observations indicate that the fundamental binding area on these starches is essentially the same. Natural and chemically modified starches are among the most useful biopolymers employed in the industry. Our study demonstrates that SBD binds effectively to both anionic and cationic starch.

Paldi, Tzur; Levy, Ilan; Shoseyov, Oded

2003-01-01

223

An optimized method for Aspergillus niger spore production on natural carrier substrates.  

PubMed

Aspergillus niger spores have wide ranging applications in the fermentation industry as well as in wastewater treatment. We present an optimized method for production of A. niger spores on natural substrates such as rice, split pea, and millet. The specific productivity (number of spores per gram of dry substrate) was 31-fold greater and volumetric productivity was 750-fold greater compared to agar slopes. The important process variables were incubation temperature, moisture content, and inoculum quantity. We find that the optimal condition for total spore count is different from the viable spore count for millet. The optimum lies in a narrow region defined by the process parameters. Of the three substrates tested split pea gave the highest specific spore productivity of 3.1 x 10(10) spores per gram of dry substrate. This is the first report of systematic study on the effect of process parameters on spore viability. The method of A. niger spore production on natural substrate appears advantageous as compared to the currently practiced method in terms of scale-up, cost, and ease of operation. PMID:14656142

Bapat, Prashant M; Kundu, Sucharita; Wangikar, Pramod P

2003-01-01

224

Mechanisms of interaction of chromium with Aspergillus niger var tubingensis strain Ed8.  

PubMed

Experiments were conducted to determine the mechanisms of interaction with chromium of Aspergillus niger var tubingensis strain Ed8 in batch culture and in bioreactor experiments. Results obtained in this work showed that the interaction of A. niger var tubingensis Ed8 with Cr(VI) is based mainly in a reduction process and also, secondly, in a sorption process. Using electron microscopy techniques the ultrathin sections obtained from the mycelium biomass produced by the fungus in batch cultures showed the ability to incorporate Cr intracellulary, into low electron-dense inclusions, but not extracellularly. On the other hand, cultures without Cr(VI) of A. niger var tubingensis Ed8, grown in a bubble column bioreactor, reduced Cr(VI) immediately after repeated addition of this oxyanion; after six loads, 460 mg Cr(VI) was reduced to Cr(III) in 60 h, corresponding to a reduction rate of 2.62 mg Cr(VI)g(-1) dry biomass h(-1). PMID:24607453

Coreńo-Alonso, A; Solé, A; Diestra, E; Esteve, I; Gutiérrez-Corona, J F; Reyna López, G E; Fernández, F J; Tomasini, A

2014-04-01

225

Regulation of the alpha-glucuronidase-encoding gene ( aguA) from Aspergillus niger.  

PubMed

The alpha-glucuronidase gene aguA from Aspergillus niger was cloned and characterised. Analysis of the promoter region of aguA revealed the presence of four putative binding sites for the major carbon catabolite repressor protein CREA and one putative binding site for the transcriptional activator XLNR. In addition, a sequence motif was detected which differed only in the last nucleotide from the XLNR consensus site. A construct in which part of the aguA coding region was deleted still resulted in production of a stable mRNA upon transformation of A. niger. The putative XLNR binding sites and two of the putative CREA binding sites were mutated individually in this construct and the effects on expression were examined in A. niger transformants. Northern analysis of the transformants revealed that the consensus XLNR site is not actually functional in the aguA promoter, whereas the sequence that diverges from the consensus at a single position is functional. This indicates that XLNR is also able to bind to the sequence GGCTAG, and the XLNR binding site consensus should therefore be changed to GGCTAR. Both CREA sites are functional, indicating that CREA has a strong influence on aguA expression. A detailed expression analysis of aguA in four genetic backgrounds revealed a second regulatory system involved in activation of aguA gene expression. This system responds to the presence of glucuronic and galacturonic acids, and is not dependent on XLNR. PMID:12242504

de Vries, R P; van de Vondervoort, P J I; Hendriks, L; van de Belt, M; Visser, J

2002-09-01

226

Effects of a defective ERAD pathway on growth and heterologous protein production in Aspergillus niger  

PubMed Central

Endoplasmic reticulum associated degradation (ERAD) is a conserved mechanism to remove misfolded proteins from the ER by targeting them to the proteasome for degradation. To assess the role of ERAD in filamentous fungi, we have examined the consequences of disrupting putative ERAD components in the filamentous fungus Aspergillus niger. Deletion of derA, doaA, hrdC, mifA, or mnsA in A. niger yields viable strains, and with the exception of doaA, no significant growth phenotype is observed when compared to the parental strain. The gene deletion mutants were also made in A. niger strains containing single- or multicopies of a glucoamylase–glucuronidase (GlaGus) gene fusion. The induction of the unfolded protein response (UPR) target genes (bipA and pdiA) was dependent on the copy number of the heterologous gene and the ERAD gene deleted. The highest induction of UPR target genes was observed in ERAD mutants containing multiple copies of the GlaGus gene. Western blot analysis revealed that deletion of the derA gene in the multicopy GlaGus overexpressing strain resulted in a 6-fold increase in the intracellular amount of GlaGus protein detected. Our results suggest that impairing some components of the ERAD pathway in combination with high expression levels of the heterologous protein results in higher intracellular protein levels, indicating a delay in protein degradation.

Carvalho, Neuza D. S. P.; Arentshorst, Mark; Kooistra, Rolf; Stam, Hein; Sagt, Cees M.; van den Hondel, Cees A. M. J. J.

2010-01-01

227

Comparative analysis of calcium gluconate and sodium gluconate techniques for the production of gluconic acid by Aspergillus niger  

Microsoft Academic Search

Sodium gluconate and calcium gluconate methods are important techniques available for gluconic acid fermentation. The comparative analysis of these fermentations has been addressed using Aspergillus niger. The techniques are equally influenced by the spores age in slant growth, inoculum level in germination and production media, different levels of Fe, Cu, Zn and Mn. Sodium gluconate method is promising with respect

D. Subba Rao; T. Panda

1993-01-01

228

Influence of sucrose concentration and phosphate limitation on citric acid production by immobilized cells of Aspergillus niger  

Microsoft Academic Search

Immobilized cells of Aspergillus niger needed a lower initial sucrose concentration than free cells in order to obtain maximal yields of citric acid production. High sucrose concentrations led to reduced yields and increased polyol formation (glycerol, erythritol, arabitol). Continuous fermentation with media containing low sugar concentrations prevented the formation of polyols. The change from nitrogen-limited to phosphate-limited precultivation of immobilized

S. Honecker; B. Bisping; Zhu Yang; H.-J. Rehm

1989-01-01

229

The influence of type and concentration of the carbon source on production of citric acid by Aspergillus niger  

Microsoft Academic Search

The influence of various carbon sources and their concentration on the production of citrate by Aspergillus niger has been investigated. The sugars maltose, sucrose, glucose, mannose and fructose (in the given order) were carbon sources giving high yields of citric acid. Optimal yields were observed at sugar concentrations of 10% (w\\/v), with the exception of glucose (7.5%). No citric acid

Ding-Bang Xu; Cynthia P. Madrid; Max Rfihr; Christian P. Kubicek

1989-01-01

230

Regulation of citric acid production by oxygen: Effect of dissolved oxygen tension on adenylate levels and respiration in Aspergillus niger  

Microsoft Academic Search

The mechanism of the control of citric acid accumulation by oxygen was investigated by means of pilot plant fermentation using Aspergillus niger. The critical dissolved oxygen tension (DOT) for oxygen uptake of this fungus was about 18–21 and 23–26 mbar for trophophase and idiophase, respectively. Minimal DOT for citric acid production was about 25 mbar. Citric acid production increased steadily

C. P. Kubicek; O. Zehentgruber; Housam El-Kalak; M. Röhr

1980-01-01

231

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

Microsoft Academic Search

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

Yuko Ikeda; Enock Y. Park; Naoyuki Okuda

2006-01-01

232

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

PubMed

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

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

2011-01-01

233

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

234

Differential Expression of Three ?-Galactosidase Genes and a Single ?-Galactosidase Gene from Aspergillus niger  

PubMed Central

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

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

1999-01-01

235

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

236

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

PubMed

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

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

2014-03-01

237

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

PubMed

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

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

2014-05-01

238

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

239

Amylolysis of raw corn by Aspergillus niger for simultaneous ethanol fermentation  

SciTech Connect

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

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

1987-01-01

240

Development of an unmarked gene deletion system for the filamentous fungi Aspergillus niger and Talaromyces versatilis.  

PubMed

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

Delmas, Stéphane; Llanos, Agustina; Parrou, Jean-Luc; Kokolski, Matthew; Pullan, Steven T; Shunburne, Lee; Archer, David B

2014-06-01

241

Biosorption of C.I. Direct Blue 199 from aqueous solution by nonviable Aspergillus niger.  

PubMed

The capacity and mechanism with which nonviable Aspergillus niger removed the textile dye, C.I. Direct Blue 199, from aqueous solution was investigated using different parameters, such as initial dye concentration, pH and temperature. In batch experiments, the biosorption capacity increased with decrease in pH, and the maximum dye uptake capacity of the biosorbent was 29.96 mg g(-1) at 400 mg L(-1) dye concentration and 45 degrees C. The Langmuir and Freundlich models were able to describe the biosorption equilibrium of C.I. Direct Blue 199 onto the fungal biomass. Biosorption followed a pseudo-second order kinetic model with high correlation coefficients (r(2)>0.99). Thermodynamic studies revealed that the biosorption process was successful, spontaneous and endothermic in nature. PMID:19879044

Xiong, Xiao-Jing; Meng, Xue-Jiao; Zheng, Tian-Ling

2010-03-15

242

Novel oligomannose-type sugar chains derived from glucose oxidase of Aspergillus niger.  

PubMed

The primary structure of the N-linked sugar chains of glucose oxidase from Aspergillus niger was investigated. These sugar chains were released from the polypeptide backbone by hydrazinolysis, and the reducing ends of the sugar chains were pyridylaminated. HPLC of the pyridylamino sugar chains with an amide-silica column showed at least seven sugar chain peaks. Chemical and exoglycosidase digestion and 400 lMHz H-NMR studies of the sugar chains of lower molecular weight showed that these were novel oligomannose-type sugar chains, (Man)5-7 (GlcNAc)2, with the structure: +/- Man alpha 1----3Man alpha 1----3(Man alpha 1----6)Man alpha 1----6(+/- Man alpha 1----3Man alpha 1---3)Man )Man beta 1----4GlcNAc beta 1----4GlcNAc. PMID:1772443

Takegawa, K; Kondo, A; Iwamoto, H; Fujiwara, K; Hosokawa, Y; Kato, I; Hiromi, K; Iwahara, S

1991-09-01

243

[Effect of detergents on the hydroxylation of indolyl-3-acetic acid by an Aspergillus niger culture].  

PubMed

A possibility to increase the hydroxylating activity of Aspergillus niger IBFM F-212 under the action of detergents was studied during transformation of indolyl-3-acetic acid (IAA). The following non-ionogenic surface-active compounds were mainly used: Tweens, Spans, polyethyleneglycol (PEG-400). The effect of the detergents was studied at the stages of growth, transformation and preincubation. At the stage of growth, the best effect was produced by Tween-80. At the stages of transformation and preincubation, the hydroxylating activity increased 1.5 times under the action of a number of Spans and PEG-400. No total positive effect of the detergents on the enzyme activity was found at the stages of growth and transformation. The results suggest that the cellular permeability changes under the action of detergents and the hydroxylating activity of the culture increases as the result. PMID:7412617

Baklashova, T G; Koshcheenko, K A

1980-01-01

244

Temperature-stress tolerance of the fungal strain Aspergillus niger 26: physiological and ultrastructural changes.  

PubMed

The study focuses on the morphological and physiological cell responses to oxidative stress induced by high temperature treatment in the industrially relevant fungus Aspergillus niger 26. Temperatures above 30 °C lead to growth suppression and changes in morphological characteristics: decrease in the size of hyphal elements and increase in "active length" by switching from slightly branched long filaments to a multitude of branched forms containing active cytoplasm. Transmission electron microscopy of fungal cultures heated at 40 °C demonstrated abnormal wavy septation with reduced amount of chitin (as shown by WGA-gold labelling), intrahyphal hyphae development, disintegration of mitochondria and extensive autolysis. Temperature-dependent decrease in the total intracellular protein content and a sharp increase (six to tenfold) in oxidatively damaged proteins were also demonstrated. Elevated temperatures caused a two and threefold increase in catalase and superoxide dismutase activities, respectively. PMID:24366816

Abrashev, Radoslav; Stoitsova, Stoyanka; Krumova, Ekaterina; Pashova, Svetlana; Paunova-Krasteva, Tsvetelina; Vassilev, Spassen; Dolashka-Angelova, Pavlina; Angelova, Maria

2014-05-01

245

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

246

Aspergillus uvarum sp. nov., an uniseriate black Aspergillus species isolated from grapes in Europe.  

PubMed

A novel species, Aspergillus uvarum sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on internal transcribed spacers (ITS), beta-tubulin and calmodulin gene sequences, by AFLP analysis and by extrolite profiles. Aspergillus uvarum sp. nov. isolates produced secalonic acid, common to other Aspergillus japonicus-related taxa, and geodin, erdin and dihydrogeodin, which are not produced by any other black aspergilli. None of the isolates were found to produce ochratoxin A. The novel species is most closely related to two atypical strains of Aspergillus aculeatus, CBS 114.80 and CBS 620.78, and was isolated from grape berries in Portugal, Italy, France, Israel, Greece and Spain. The type strain of Aspergillus uvarum sp. nov. is IMI 388523T=CBS 127591T=ITEM 4834T=IBT26606T. PMID:18398215

Perrone, Giancarlo; Varga, János; Susca, Antonia; Frisvad, Jens C; Stea, Gaetano; Kocsubé, Sándor; Tóth, Beáta; Kozakiewicz, Zofia; Samson, Robert A

2008-04-01

247

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

PubMed

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 by gel electrophoresis. Enzyme activity is maximal at pH 7.0 and 45 degrees C. The fraction containing the enzyme activity contained at least five proteins. The N-terminal amino acid sequences of four of these proteins were determined. The amino acid sequences were aligned with EST sequences from A. niger, and an EST sequence that showed 100% identity to all four sequences was identified. Using this EST sequence the gene encoding oxaloacetate hydrolase (oah) was cloned by inverse PCR. It consists of an ORF of 1227 bp with two introns of 92 and 112 bp, respectively. The gene encodes a protein of 341 amino acids with a molecular mass of 37 kDa. Under the growth conditions tested, the highest oah expression was found for growth on acetate as carbon source. The gene was expressed only at pH values higher than 4.0. PMID:10778746

Pedersen, H; Hjort, C; Nielsen, J

2000-03-01

248

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

249

Esterification of ferulic acid with polyols using a ferulic acid esterase from Aspergillus niger.  

PubMed

Commercially available enzyme preparations were screened for enzymes that have a high ability to catalyze direct ester-synthesis of ferulic acid with glycerol. Only a preparation, Pectinase PL "Amano" produced by Aspergillus niger, feruloylated glycerol under the experimental conditions. The enzyme responsible for the esterification was purified and characterized. This enzyme, called FAE-PL, was found to be quite similar to an A. niger ferulic acid esterase (FAE-III) in terms of molecular mass, pH and temperature optima, substrate specificity on synthetic substrates, and the N-terminal amino acid sequence. FAE-PL highly catalyzed direct esterification of ferulic acid and sinapinic acid with glycerol. FAE-PL could feruloylate monomeric sugars including arabinose, fructose, galactose, glucose, and xylose. We determined the suitable conditions for direct esterification of ferulic acid with glycerol to be as follows: 1% ferulic acid in the presence of 85% glycerol and 5% dimethyl sulfoxide at pH 4.0 and 50 degrees C. Under these conditions, 81% of ferulic acid could be converted to 1-glyceryl ferulate, which was identified by (1)H-NMR. The ability of 1-glyceryl ferulate to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals was higher than that of the anti-oxidant butyl hydroxytoluene. PMID:16714088

Tsuchiyama, Moriyasu; Sakamoto, Tatsuji; Fujita, Tomoyuki; Murata, Shuichi; Kawasaki, Haruhiko

2006-07-01

250

Construction of a flocculent Saccharomyces cerevisiae strain secreting high levels of Aspergillus niger beta-galactosidase.  

PubMed

A flocculent Saccharomyces cerevisiae strain secreting Aspergillus niger beta-galactosidase activity was constructed by transforming S. cerevisiae NCYC869-A3 strain with plasmid pVK1.1 harboring the A. niger beta-galactosidase gene, lacA, under the control of the ADH1 promoter and terminator. Compared to other recombinant S. cerevisiae strains, this recombinant yeast has higher levels of extracellular beta-galactosidase activity. In shake-flask cultures, the beta-galactosidase activity detected in the supernatant was 20 times higher than that obtained with previously constructed strains (Domingues et al. 2000a). In bioreactor culture, with cheese-whey permeate as substrate, a yield of 878.0 nkat/gsubstrate was obtained. The recombinant strain is an attractive alternative to other fungal beta-galactosidase production systems as the enzyme is produced in a rather pure form. Moreover, the use of flocculating yeast cells allows for enzyme production with high productivity in continuous fermentation systems with facilitated downstream processing. PMID:11956748

Domingues, L; Teixeira, J A; Penttilä, M; Lima, N

2002-04-01

251

Aspergillus niger RhaR, a regulator involved in L-rhamnose release and catabolism.  

PubMed

The genome of the filamentous fungus Aspergillus niger is rich in genes encoding pectinases, a broad class of enzymes that have been extensively studied due to their use in industrial applications. The sequencing of the A. niger genome provided more knowledge concerning the individual pectinolytic genes, but little is known about the regulatory genes involved in pectin degradation. Understanding regulation of the pectinolytic genes provides a tool to optimize the production of pectinases in this industrially important fungus. This study describes the identification and characterization of one of the activators of pectinase-encoding genes, RhaR. Inactivation of the gene encoding this regulator resulted in down-regulation of genes involved in the release of L-rhamnose from the pectin substructure rhamnogalacturonan I, as well as catabolism of this monosaccharide. The rhaR disruptant was unable to grow on L-rhamnose, but only a small reduction in growth on pectin was observed. This is likely caused by the presence of a second, so far unknown regulator that responds to the presence of D-galacturonic acid. PMID:24682478

Gruben, Birgit S; Zhou, Miaomiao; Wiebenga, Ad; Ballering, Joost; Overkamp, Karin M; Punt, Peter J; de Vries, Ronald P

2014-06-01

252

Molecular and biochemical characterization of a novel intracellular invertase from Aspergillus niger with transfructosylating activity.  

PubMed

A novel subfamily of putative intracellular invertase enzymes (glycoside hydrolase family 32) has previously been identified in fungal genomes. Here, we report phylogenetic, molecular, and biochemical characteristics of SucB, one of two novel intracellular invertases identified in Aspergillus niger. The sucB gene was expressed in Escherichia coli and an invertase-negative strain of Saccharomyces cerevisiae. Enzyme purified from E. coli lysate displayed a molecular mass of 75 kDa, judging from sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Its optimum pH and temperature for sucrose hydrolysis were determined to be 5.0 and 37 to 40 degrees C, respectively. In addition to sucrose, the enzyme hydrolyzed 1-kestose, nystose, and raffinose but not inulin and levan. SucB produced 1-kestose and nystose from sucrose and 1-kestose, respectively. With nystose as a substrate, products up to a degree of polymerization of 4 were observed. SucB displayed typical Michaelis-Menten kinetics with substrate inhibition on sucrose (apparent K(m), K(i), and V(max) of 2.0 +/- 0.2 mM, 268.1 +/- 18.1 mM, and 6.6 +/- 0.2 mumol min(-1) mg(-1) of protein [total activity], respectively). At sucrose concentrations up to 400 mM, transfructosylation (FTF) activity contributed approximately 20 to 30% to total activity. At higher sucrose concentrations, FTF activity increased to up to 50% of total activity. Disruption of sucB in A. niger resulted in an earlier onset of sporulation on solid medium containing various carbon sources, whereas no alteration of growth in liquid culture medium was observed. SucB thus does not play an essential role in inulin or sucrose catabolism in A. niger but may be needed for the intracellular conversion of sucrose to fructose, glucose, and small oligosaccharides. PMID:17293485

Goosen, Coenie; Yuan, Xiao-Lian; van Munster, Jolanda M; Ram, Arthur F J; van der Maarel, Marc J E C; Dijkhuizen, Lubbert

2007-04-01

253

Recombination of mitochondrial DNA without selection pressure among compatible strains of the Aspergillus niger species aggregate  

Microsoft Academic Search

Previous mitochondrial transmission experiments between oligomycin-resistant and oligomycin-sensitive incompatible strains\\u000a of the A. niger aggregate bearing various mtDNA RFLP profiles resulted in a great variety of mitochondrial recombinants under selection pressure.\\u000a Apart from the recombinant mtDNAs, resistant clones harbouring unchanged RFLP profiles of resistant donor mtDNAs with the\\u000a recipient nuclear backgrounds were rarely isolated. These strains were anastomosed with nuclearly

Beáta Tóth; Zsuzsanna Hamari; Lajos Ferenczy; János Varga; Ferenc Kevei

1998-01-01

254

Proteome analysis of Aspergillus niger: Lactate added in starch-containing medium can increase production of the mycotoxin fumonisin B2 by modifying acetylCoA metabolism  

Microsoft Academic Search

BACKGROUND: Aspergillus niger is a filamentous fungus found in the environment, on foods and feeds and is used as host for production of organic acids, enzymes and proteins. The mycotoxin fumonisin B2 was recently found to be produced by A. niger and hence very little is known about production and regulation of this metabolite. Proteome analysis was used with the

Louise M Sřrensen; Rene Lametsch; Mikael R Andersen; Per V Nielsen; Jens C Frisvad

2009-01-01

255

Purification and characterization of a nitrilase from Aspergillus niger K10.  

PubMed

Aspergillus niger K10 cultivated on 2-cyanopyridine produced high levels of an intracellular nitrilase, which was partially purified (18.6-fold) with a 24% yield. The N-terminal amino acid sequence of the enzyme was highly homologous with that of a putative nitrilase from Aspergillus fumigatus Af293. The enzyme was copurified with two proteins, the N-terminal amino acid sequences of which revealed high homology with those of hsp60 and an ubiquitin-conjugating enzyme. The nitrilase exhibited maximum activity (91.6 U mg(-1)) at 45 degrees C and pH 8.0. Its preferred substrates, in the descending order, were 4-cyanopyridine, benzonitrile, 1,4-dicyanobenzene, thiophen-2-acetonitrile, 3-chlorobenzonitrile, 3-cyanopyridine, and 4-chlorobenzonitrile. Formation of amides as by-products was most intensive, in the descending order, for 2-cyanopyridine, 4-chlorobenzonitrile, 4-cyanopyridine, and 1,4-dicyanobenzene. The enzyme stability was markedly improved in the presence of D: -sorbitol or xylitol (20% w/v each). p-Hydroxymercuribenzoate and heavy metal ions were the most powerful inhibitors of the enzyme. PMID:17061133

Kaplan, Ondrej; Vejvoda, Vojtech; Plíhal, Ondrej; Pompach, Petr; Kavan, Daniel; Bojarová, Pavla; Bezouska, Karel; Macková, Martina; Cantarella, Maria; Jirk?, Vladimír; Kren, Vladimír; Martínková, Ludmila

2006-12-01

256

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

SciTech Connect

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

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

2008-01-01

257

Bioconversion of Agave tequilana fructans by exo-inulinases from indigenous Aspergillus niger CH-A-2010 enhances ethanol production from raw Agave tequilana juice.  

PubMed

Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 °C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme(®) (Novozymes Corp, Bagsvćrd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol. PMID:23160922

Huitrón, Carlos; Pérez, Rosalba; Gutiérrez, Luís; Lappe, Patricia; Petrosyan, Pavel; Villegas, Jesús; Aguilar, Cecilia; Rocha-Zavaleta, Leticia; Blancas, Abel

2013-01-01

258

Secretory expression and purification of Aspergillus niger glucose oxidase in Saccharomyces cerevisiae mutant deficient in PMR1 gene  

Microsoft Academic Search

The gene encoding glucose oxidase (GOD) from Aspergillus niger was expressed as a secretory product in the yeast Saccharomyces cerevisiae. Six consecutive histidine residues were fused to the C-terminus of GOD to facilitate purification. The recombinant GOD-His6 secreted by S. cerevisiae migrated as a broad diffuse band on SDS–PAGE, with an apparent molecular weight higher than that in natural A.

Ji-Hyun Ko; Moon Sun Hahm; Hyun Ah Kang; Soo Wan Nam; Bong Hyun Chung

2002-01-01

259

Enhanced production of extracellular ribonuclease from Aspergillus niger by optimization of culture conditions using response surface methodology  

Microsoft Academic Search

Response surface methodology were used to study the cumulative effect of the culture conditions and to enhance the production of extracellular ribonuclease in shake flask fermentation by Aspergillus niger. These conditions considered include initial pH, inoculum size, total carbon, ratio of glucose to corn powder, NH4NO3 and K2SO4. The relative importance of these conditions on ribonuclease production was investigated by

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

2004-01-01

260

Yam bean starch: a novel substrate for citric acid production by the protease-negative mutant strain of Aspergillus niger  

Microsoft Academic Search

Selection of protease-negative mutant strains of Aspergillus niger in semi-solid culture was carried out in order to enhance citric acid production from yam bean. The protease-negative mutants were obtained by UV-irradiation of the parental strain Yang no. 2. Using a halo-selection medium, a number of mutants with decreased extracellular protease activity were selected. Citric acid productivity by the selected mutant

Somsak Sarangbin; Yuwadee Watanapokasin

1999-01-01

261

Optimization for xylanase and cellulase production from Aspergillus niger ATTC 6275 in palm oil mill wastes and its application  

Microsoft Academic Search

Optimization of enzyme production from Aspergillus niger ATCC 6275 under both submerged and solid-substrate cultivation was investigated. Results from submerged cultivation using palm oil mill effluent revealed that pretreatment of ground palm cake did not improve enzyme production. Addition of 0.60g NH4NO3\\/l generated maximum activity of xylanase and cellulase (CMCase). The optimum aeration rate was 1.2 v\\/v min. Under solid-substrate

P. Prasertsan; A. H-Kittikul; A. Kunghae; J. Maneesri; S. Oi

1997-01-01

262

Production of tannase by Aspergillus niger HA37 growing on tannic acid and Olive Mill Waste Waters  

Microsoft Academic Search

Production of tannase (tannin acyl hydrolase, EC 3.1.1.20) by Aspergillus nigerHA37 on a synthetic culture medium containing tannic acid at different concentrations has been studied. Maximal enzymatic activity increased according to the initial concentration of tannic acid; respectively 0.6, 0.9 and 1.5 enzyme activity units (EU) ml?1 medium in the presence of 0.2%, 0.5% and 1% of tannic acid. Tannase

H. Aissam; F. Errachidi; M. J. Penninckx; M. Merzouki; M. Benlemlih

2005-01-01

263

Environment friendly crosslinked chitosan as a matrix for selective adsorption and purification of lipase of Aspergillus niger.  

PubMed

Chitosan and its derivatives have been used as affinity matrices for purification of lipase from Aspergillus niger NCIM 1207. Trimellitic anhydride (TMA)-crosslinked deacetylated chitin adsorbed lipase selectively, yielding approximately 5-fold purification of the crude lipase with 70% yield. Further 9-fold purification occurred on eluting through Sephacryl-100. These results suggest that chitosan derivatives can be used as inexpensive biopolymer matrices for the purification of lipases for industrial applications. PMID:18789352

Trimukhe, K D; Mahadik, N D; Gokhale, D V; Varma, A J

2008-12-01

264

Water activity, solute and temperature modify growth and spore production of wild type and genetically engineered Aspergillus niger strains  

Microsoft Academic Search

The effect of interactions of water activity (aw) (0.99–0.90), temperature (20, 30 and 35°C) and modifying aw solute (glycerol, NaCl) on growth and sporulation of a wild-type strain of Aspergillus niger (W) and two genetically engineered lysozyme-producing strains (L11, B1) was examined for the first time. Maximum growth rates were achieved for both strains (L11 and B1) under moderate aW

Roberto Parra; David Aldred; David B. Archer; Naresh Magan

2004-01-01

265

Enhanced production of verbenol, a highly valued food flavourant, by an intergeneric fusant strain of Aspergillus niger and Penicillium digitatum.  

PubMed

An intergeneric hybrid, obtained from Aspergillus niger and Penicillium digitatum, biotransformed (-)-cis-alpha-pinene (5 mg/25 ml) into (-)-cis-verbenol (60%; 1.08 mg/g of biomass) in 6 h compared with 0.18 mg/g of biomass for verbenol (10-15%; 0.18-0.27 mg/g of biomass) in the initial parent cultures. PMID:12630902

Rao, Smitha C V; Rao, Rati; Agrawal, Renu

2003-04-01

266

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

267

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

268

Optimization of nutrient concentration for citric acid production by solid-state culture of Aspergillus niger on polyurethane foams  

Microsoft Academic Search

Citric acid production from mussel processing effluents by Aspergillus niger in solid-state culture was studied using polyurethane foam particles soaked with the culture medium. Conditions were used that allowed comparison of the results with those obtained before in submerged culture and the attribution of the differences to the characteristics of solid-state culture.A screening of several strains gave different results than

J. Pintado; A. Torrado; M. P. González; M. A. Murado

1998-01-01

269

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

PubMed

This article reports the production of high levels of L-asparaginase from a new isolate of Aspergillus niger in solid state fermentation (SSF) using agro-wastes 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. mungo and C. cajan. A 96-h fermentation time under aerobic condition with moisture content of 70%, 30 min of cooking time and 1205-1405 micro range of particle size in SSF appeared optimal for enzyme production. Enzyme yield was maximum (40.9 +/- 3.35 U/g of dry substrate) at pH 6.5 and temperature 30 +/- 2 degrees C. The optimum temperature and pH for enzyme activity were 40 degrees C and 6.5, respectively. The study suggests that choosing an appropriate substrate when coupled with process level optimization improves enzyme production markedly. Developing an asparaginase production process based on bran of G. max as a substrate in SSF is economically attractive as it is a cheap and readily available raw material in agriculture-based countries. PMID:17057254

Mishra, Abha

2006-10-01

270

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

PubMed Central

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

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

2012-01-01

271

High-level expression of aspergillus niger b-galactosidase in ashbya gossypii.  

PubMed

Ashbya gossypii has been recently considered as a host for the expression of recombinant proteins. The production levels achieved thus far were similar to those obtained with Saccharomyces cerevisiae for the same proteins. Here, the b-galactosidase from Aspergillus niger was successfully expressed and secreted by A. gossypii from 2-mm plasmids carrying the native signal sequence at higher levels than those secreted by S. cerevisiae laboratorial strains. Four different constitutive promoters were used to regulate the expression of bgalactosidase: A. gossypii AgTEF and AgGPD promoters, and S. cerevisiae ScADH1 and ScPGK1 promoters. The native AgTEF promoter drove the highest expression levels of recombinant b-galactosidase in A. gossypii, leading to 2- and 8-fold higher extracellular activity than the AgGPD promoter and the heterologous promoters, respectively. In similar production conditions, the levels of active b-galactosidase secreted by A. gossypii were up to 37 times higher than those secreted by recombinant S. cerevisiae and 2.5 times higher than those previously reported for the b-galactosidase-high producing S. cerevisiae NCYC869-A3/pVK1.1. The substitution of glucose by glycerol in the production medium led to a 1.5-fold increase in the secretion of active b-galactosidase by A. gossypii. Recombinant b-galactosidase secreted by A. gossypii was extensively glycosylated, as are the native A. niger b-galactosidase and recombinant b-galactosidase produced by yeast. These results highlight the potential of A. gossypii as a recombinant protein producer and open new perspectives to further optimize recombinant protein secretion in this fungus. PMID:24851247

Magalhes, Frederico; Aguiar, Tatiana Q; Oliveira, Carla; Domingues, Lucília

2014-01-01

272

Production and characterization of recombinant glucose oxidase from Aspergillus niger expressed in Pichia pastoris.  

PubMed

Recombinant glucose oxidase from Aspergillus niger expressed in Pichia pastoris by fed-batch fermentation was purified and assessed with 1·26 purification fold to homogeneity using Q-Sepharose F.F. chromatography. The enzyme was determined by SDS-PAGE and gradient PAGE, which showed a dimeric form of 150 kDa. The purified rGOD was proved to be a glycoprotein, and the content of which was estimated to be 36·7 and 25·14% by phenol-sulfuric acid and anthrone-sulfuric acid methods. Characteristics demonstrated that the highest activity was in pH 6·0 at 40°C and was stable at a broad pH range from 4·0 to 9·0 at 55°C or below. The optimum substrate for this enzyme was d-glucose, and the Km was 21·06 mmol l(-1) as well as the Vmax was 359 ?mol min(-1) mg(-1). rGOD possessed high resistance to various chemicals except for Hg(2+), Fe(2+), Ag(+), Cu(2+), 1,4-dithiothreitol, sodium dodecyl sulfate and ascorbic acid. In addition, the inhibitors also exhibited intensive fluorescence quenching effect on rGOD. Significance and impact of the study: Glucose oxidase is a very important enzyme produced by several species. However, large-scale applications have always been postponed by its complexity in fermentation and purification. Our research focused on developing new purification strategy of recombinant GOD from A. niger expressed in P. pastoris. Here, we described this novel one-step purification method and subsequent research in the characteristics of rGOD which showed different results from previous work. These can open new opportunities to increase its application. PMID:24283586

Meng, Y; Zhao, M; Yang, M; Zhang, Q; Hao, J; Meng, Y

2014-04-01

273

Biochar Enhances Aspergillus niger Rock Phosphate Solubilization by Increasing Organic Acid Production and Alleviating Fluoride Toxicity.  

PubMed

During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F(-)) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F(-) adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus niger was examined. Al2O3 adsorbed part of the F(-) released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F(-) while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F(-) measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F(-) per liter can be removed from solution by biochar when added at 3 g liter(-1) to the culture medium. Thus, biochar acted as an F(-) sink during RP solubilization and led to an F(-) concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F(-) and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F(-), the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP. PMID:24610849

Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo; Costa, Maurício Dutra

2014-05-01

274

Bimutation breeding of Aspergillus niger strain for enhancing ?-mannanase production by solid-state fermentation.  

PubMed

A parent strain Aspergillus niger LW-1 was mutated by the compound mutagenesis of vacuum microwave (VMW) and ethyl methane sulfonate (EMS). A mutant strain, designated as A. niger E-30, with high- and stable-yield ?-mannanase was obtained through a series of screening. The ?-mannanase activity of the mutant strain E-30, cultivated on the basic fermentation medium at 32°C for 96 h, reached 36,675 U/g dried koji, being 1.98-fold higher than that (18,50 1U/g dried koji) of the parent strain LW-1. The purified E-30 ?-mannanase, a glycoprotein with a carbohydrate content of 19.6%, had an apparent molecular weight of about 42.0 kDa by SDS-PAGE. Its optimal pH and temperature were 3.5 and 65°C, respectively. It was highly stable at a pH range of 3.5-7.0 and at a temperature of 60°C and below. The kinetic parameters K(m) and V(max), toward locust bean gum and at pH 4.8 and 50°C, were 3.68 mg/mL and 1067.5 U/mg, respectively. The ?-mannanase activity was not significantly affected by an array of metal ions and EDTA, but strongly inhibited by Ag(+) and Hg(2+). In addition, the hydrolytic conditions of konjak glucomannan using the purified E-30 ?-mannanase were optimized as follows: konjak gum solution 240 g/L (dissolved in deionized water), hydrolytic temperature 50°C, ?-mannanase dosage 120 U/g konjak gum, and hydrolytic time 8 h. PMID:21867993

Wu, Minchen; Tang, Cunduo; Li, Jianfang; Zhang, Huimin; Guo, Jing

2011-10-18

275

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

PubMed

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

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

2006-06-01

276

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

2005-12-01

277

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

PubMed Central

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.

Hayer, Kimran; Stratford, Malcolm

2013-01-01

278

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

PubMed Central

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

Rodriguez, Angel Pereira; Leiro, Rafael Fernandez; Trillo, M Cristina; Cerdan, M Esperanza; Siso, M Isabel Gonzalez; Becerra, Manuel

2006-01-01

279

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

280

Cladal relatedness among Aspergillus oryzae isolates and Aspergillus flavus S and L morphotype isolates.  

PubMed

Aspergillus flavus is the main etiological agent for aflatoxin contamination of crops. Its close relative, A. oryzae, does not produce aflatoxins and has been widely used to produce fermented foods. We compared the phylogeny of A. oryzae isolates and L- and S-type sclerotial isolates of A. flavus using single nucleotide polymorphisms in the omtA gene in the aflatoxin biosynthesis gene cluster and deletions in and distal to the norB-cypA intergenic region as phylogenetic signals. Aflatoxin-producing ability and sclerotial size also were weighted in the analysis. Like A. flavus, the A. oryzae isolates form a polyphyletic assemblage. A. oryzae isolates in one clade strikingly resemble an A. flavus subgroup of atoxigenic L-type isolates. All toxigenic S-type isolates closely resemble another subgroup of atoxigenic L-type isolates. Because atoxigenic S-type isolates are extremely rare, we hypothesize that loss of aflatoxin production in S-type isolates may occur concomitantly with a change to L-type sclerotia. All toxigenic L-type isolates, unlike A. oryzae, have a 1.0 kb deletion in the norB-cypA region. Although A. oryzae isolates, like S-type, have a 1.5 kb deletion in the norB-cypA region, none were cladally related to S-type A. flavus isolates. Our results show that A. flavus populations are genetically diverse. A. oryzae isolates may descend from certain atoxigenic L-type A. flavus isolates. PMID:16430983

Chang, Perng-Kuang; Ehrlich, Kenneth C; Hua, Sui-Sheng T

2006-04-25

281

Fate and Role of Ammonium Ions during Fermentation of Citric Acid by Aspergillus niger  

PubMed Central

Stoichiometric modeling of the early stages of the citric acid fermentation process by Aspergillus niger revealed that ammonium ions combine with a carbon-containing metabolite inside the cell, in a ratio 1:1, to form a nitrogen compound which is then excreted by the mycelium. High-performance liquid chromatography analysis identified glucosamine as the product of the relationship between glucose and ammonium during the early stages of the citric acid fermentation process. Slightly acidic internal pHs, extremely low ammonium ion concentrations inside the cell, and glucosamine synthesis come into direct contradiction with the earlier theory of the ammonium pool inside the cell, regarded as responsible for inhibition of the enzyme phosphofructokinase. At later fermentation stages, when the mycelium is involved in a process of fragmentation and regrowth, the addition of ammonium sulfate leads to a series of events: the formation and secretion of glucosamine in elevated amounts, the short inhibition of citrate synthesis, growth enhancement, the utilization of glucosamine, and finally, the enhancement of citric acid production rates. Obviously, the enzymatic processes underlining the phenomena need to be reexamined. As a by-product of the citric acid fermentation, glucosamine is reported for the first time here. Suitable process manipulations of the system described in this work could lead to successful glucosamine recovery at the point of its highest yield before degradation by the fungus occurs.

Papagianni, Maria; Wayman, Frank; Mattey, Michael

2005-01-01

282

Antifungal agents against Aspergillus niger for rearing rice leaffolder larvae (Lepidoptera: Pyralidae) on artificial diet.  

PubMed

Mold contamination is an important issue in insect mass rearing. Frequently used antifungal agents such as sorbic acid and methylparaben have negative impact on many lepidopteran larvae, which might be one of the reasons for the difficulty in rearing rice leaffolder, Cnaphalocrocis medinalis (Güenée). In this study, 19 antifungal agents, including 7 food preservatives, 6 antifungal drugs, and 6 agricultural fungicides, were screened for their inhibitory activities on Aspergillus niger in diets. The results demonstrated that most of the tested chemicals are unsuitable as mold inhibitors in the diets of the rice leaffolder, and the rice leaffolder neonate is sensitive to sorbic acid and methylparaben. These two mold inhibitors at commonly used concentrations were shown to impact the survival of rice leaffolder larvae fed on artificial diets. Among the tested mold inhibitors, natamycin was the safest for the rice leaffolder larvae. Much higher larva survival was observed for the larvae fed on diets containing natamycin as an antifungal agent (59 and 72% at 200 and 400 ppm, respectively). Two agricultural fungicides, tebuconazole and azoxystrobin, are also potent as mold inhibitors when used in insect diets. The mixed use of natamycin and sorbic acid, or methylparaben, and the mixed use of sorbic acid and azoxystrobin resulted in significantly higher larva survival than sorbic acid + methylparaben. Natamycin + azoxystrobin and sorbic acid + tebuconazole resulted in larva survival similar to that of sorbic acid + methylparaben. The ternary combination of natamycin, sorbic acid, and methylparaben was the best combination for the rearing of rice leaffolder. PMID:25026669

Su, Jianya; Wang, Ye-Cheng; Zhang, Shu-Kun; Ren, Xiu-Bei

2014-06-01

283

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

2012-01-01

284

Production and extraction optimization of xylanase from Aspergillus niger DFR-5 through solid-state-fermentation.  

PubMed

The effects of solid substrates, initial moisture content, moistening medium, temperature and incubation time on xylanase production by Aspergillus niger DFR-5 was studied and the highest activity (2596 IU/g dry substrate (gds)) was achieved in medium that contained wheat bran (WB) and soybean cake (SBC) at a ratio of 70:30, was moistened to 70% with MSS-2 mineral salt solution, and incubated for 6 days at 40 degrees C. Water at 37 degrees C was suitable for efficient recovery of enzyme from moldy WB-SBC medium. The extraction parameters for xylanase were optimized with respect to minimum volume of extractant using a central composite rotatable design (CCRD). The maximum recovery of xylanase (4465+/-52 IU/gds) with 92.5% desirability was obtained employing water (10 ml/gds) as extractant at 200 rpm for 60 min. The result shows that an overall 5.4-fold increase in xylanase production was obtained in concentrated form by optimizing medium components and extraction conditions. PMID:20478705

Pal, Ajay; Khanum, Farhath

2010-10-01

285

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

286

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

PubMed

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. PMID:23449730

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

2013-03-15

287

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

PubMed

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

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

2010-08-01

288

Xylanase production by Aspergillus niger FTCC 5003 using palm kernel cake in fermentative bioprocess.  

PubMed

The production of xylanase from palm kernel cake as a substrate was studied in solid substrate fermentation. The simultaneous effects of three independent variables, namely incubation temperature, initial moisture content of substrate and air flow rate on xylanase production were evaluated by response surface methodology using central composite face centered design. A total of 18 experiments were carried out in which Aspergillus niger FTCC 5003 was cultivated on palm kernel cake in a column bioreactor for 7 days under incubation temperature, moisture level and aeration rate determined. Test results showed that the highest xylanase activity of 174.88 U g(-1) was produced at incubation temperature, initial moisture level and aeration rate of 25 degrees C, 60% and 1.5 L min(-1), respectively. The statistical analysis of the experimental results revealed that the linear effect of incubation temperature and quadratic term of initial moisture content had highly significant effects on xylanase production (p<0.01). Statistical results also showed that interaction effect between incubation temperature and initial moisture content as well as interaction effect between moisture level and aeration rate influenced the yield ofxylanase at probability levels of 95%. Optimum conditions determined by statistical model for attaining maximum xylanase production were incubation temperature of 25 degrees C, initial moisture level of 63% and aeration rate of 1.76 L min(-1). The xylanase activity of 192.50 U g(-1) was obtained when solid substrate fermentation was performed under the optimal circumstances. PMID:19943460

Abdeshahian, P; Samat, N; Yusoff, W M Wan

2009-08-01

289

The effects of bioprocess parameters on extracellular proteases in a recombinant Aspergillus niger B1-D.  

PubMed

Although host proteases are often considered to have a negative impact upon heterologous protein production by filamentous fungi, relatively little is known about the pattern of their appearance in recombinant fungal bioprocesses. In the present study, we investigated extracellular proteases from a filamentous fungus, Aspergillus niger B1-D, genetically modified to secrete hen egg white lysozyme (HEWL). Our findings indicate that extracellular protease activity is only detected after the carbon source is completely utilised in batch cultures. The proteases are predominantly acid proteases and have optimal temperature for activity at around 45 degrees C. Their activity could be partially inhibited by protease inhibitors, indicating the existence of at least four kinds of proteases in these culture fluids, aspartic-, serine-, cysteine-, and metallo-proteases. Oxygen enrichment does not have any noticeable effects on extracellular protease activity except that the onset of protease activity appears earlier in oxygen enrichment runs. Oxygen enrichment stimulates HEWL production substantially, and we propose that it is related to fungal morphology. Thermal stress imposed by raising process temperature (from 25 to 30 and 35 degrees C) in early exponential phase, led to appearance of protease activity in the medium following the heat shock. Continued cultivation at high temperatures significantly reduced HEWL production, which was associated with increased activity of the extracellular proteases in these cultures. PMID:18074130

Li, Qiang; Harvey, Linda M; McNeil, Brian

2008-02-01

290

Optimization of xylanase production from Aspergillus niger for biobleaching of eucalyptus pulp.  

PubMed

A crude endo-xylanase produced by Aspergillus niger BCC14405 was investigated for its potential in pre-bleaching of chemical pulp from eucalyptus. The optimal fermentation conditions on the basis of optimization using response surface methodology included cultivation in a complex medium comprising wheat bran, rice bran, and soybean meal supplemented with yeast extract, glucose, peptone, and lactose with a starting pH of 6.0 for 7 d. This resulted in production of 89.5 IU/mL of xylanase with minor cellulase activity. Proteomic analysis using LC/MS/MS revealed that the crude enzyme was a composite of hemicellulolytic enzymes, including endo-?-1,4-xylanase and other hemicellulolytic enzymes attacking arabinoxylan and mannan. Pretreatment of the pulp at a xylanase dosage of 10 IU/g increased the brightness ceiling after the C-Eop-H bleaching step up to 3.0% using a chlorine charge with a C-factor of 0.16-0.20. Xylanase treatment also led to reduction in chlorine charge of at least 20%, with an acceptable brightness level. The enzyme pretreatment resulted in a slight increase in pulp viscosity, suggesting an increase in relative cellulose content. The crude enzyme was potent in the enzyme-aided bleaching of chemical pulp in an environmentally friendly pulping process. PMID:21670524

Khonzue, Parichart; Laothanachareon, Thanaporn; Rattanaphan, Nakul; Tinnasulanon, Phungjai; Apawasin, Saowanee; Paemanee, Atchara; Ruanglek, Vasimon; Tanapongpipat, Sutipa; Champreda, Verawat; Eurwilaichitr, Lily

2011-01-01

291

Sudden substrate dilution induces a higher rate of citric acid production by Aspergillus niger.  

PubMed Central

On the basis of the present knowledge of Aspergillus niger metabolism during citric acid fermentation, an idea on how to improve the process was formed. Initially, a higher sucrose concentration was used for the germination of spores, which caused a higher intracellular level of the osmoregulator, glycerol, to be present. When citric acid started to be excreted into the medium, the substrate was suddenly diluted. Optimization of this procedure resulted in a nearly tripled volumetric rate (grams per liter per hour) of acid production, while the overall fermentation time was halved compared with the usual batch process. Yet, a characteristic delay was observed at the start of the acid excretion after the dilution. Hypo-osmotic shock caused a prominent elevation of intracellular cyclic AMP levels. Simultaneously, the specific activity of 6-phosphofructo-1-kinase increased significantly, probably due to phosphorylation of the protein molecule by cyclic AMP-dependent protein kinase. Specific 6-phosphofructo-1-kinase activity was much higher in the treated than in the normally growing mycelium. The metabolic flow through glycolysis was expected to be higher, which should contribute to a higher volumetric rate of acid production.

Legisa, M; Gradisnik-Grapulin, M

1995-01-01

292

Purification and characterization of a beta-glucuronidase from Aspergillus niger.  

PubMed

A beta-glucuronidase from Pectinex Ultra SP-L, a commercial pectolytic enzyme preparation from Aspergillus niger, was purified 170-fold by ion-exchange chromatography and gel filtration. Apparent M(r) of the purified enzyme, estimated by denaturing gel electrophoresis and size-exclusion chromatography, were 68,000 and 71,000, respectively, indicating that the enzyme is a monomeric protein. It released uronic acids not only from p-nitrophenyl beta-glucosiduronic acid (PNP-GlcA) but also from acidic galactooligosaccharides carrying either beta-D-glucosyluronic or 4-O-methyl-beta-D-glucosyluronic residues at the nonreducing termini through beta-(1-->6)-glycosidic linkages. The enzyme exhibited a maximal activity toward these substrates at pH 3.0. A regioisomer, 3-O-beta-glucosyluronic acid-galactose, was unsusceptible to the enzyme. The enzyme did act on a polymer substrate, releasing uronic acid from the carbohydrate portion of a radish arabinogalactan-protein modified by treatment with fungal alpha-L-arabinofuranosidase. The enzyme produced acidic oligosaccharides by transglycosylation, catalyzing the transfer of uronic acid residues of PNP-GlcA and 6-O-beta-glucosyluronic acid-galactose to certain exogenous acceptor sugars such as Gal, N-acetylgalactosamine, Glc, and xylose. PMID:11423108

Kuroyama, H; Tsutsui, N; Hashimoto, Y; Tsumuraya, Y

2001-06-22

293

Purification and properties of three cellobiases from Aspergillus niger A20.  

PubMed

Three cellobiases, here called cellobiase A, B, and C, from the culture filtrate of Aspergillus niger A20, were purified by precipitation with ammonium sulphate, gel filtration through Sephadex G-75, and column chromatography of DEAE-cellulose. The purified enzymes were homogeneous on polyacrylamide disk electrophoresis. The mol wt of the purified enzymes were estimated by SDS-gel electrophoresis to be 88,000, 80,000, and 71,000 for cellobiases A, B, and C, respectively. The enzymes were active at pH 4.5 and 55-60 degrees C. The pattern of their amino acid compositions showed high contents of aspartic acid, glutamic acid, threonine, serine, and glycine. The apparent K(m) values for cellobiose were 0.9, 1.63, and 1.0 mM for cellobiases A, B, and C, respectively. Calcium ions stimulated cellobiases B and C, and Co2+ and Mg2+ ions stimulated cellobiase A. The purified enzymes hydrolyzed cellobiose and aryl-beta-D-glucosides, but they had no action on sucrose, maltose, and cellulose. The three cellobiases catalyzed transglycosylase reaction, and the major product formed from cellobiose was tetramer of glucose. PMID:10327588

Abdel-Naby, M A; Osman, M Y; Abdel-Fattah, A F

1999-01-01

294

Aspergillus Niger peritonitis in a peritoneal dialysis patient treated with eculizumab.  

PubMed

The complement system plays a vital role in preventing life-threatening infections by ensuring optimal functioning of the host immune system. Its dysregulation has been implicated in causing glomerular, hematological, and transplant-related disorders. Eculizumab a novel monoclonal antibody against complement component C5 has emerged in the recent past as the standard of care offering an effective rescue and maintenance therapy against many of these disorders. Its use has been associated with increased risk of infections predominantly with encapsulated organisms. There is no data in the literature on its effects in end-stage kidney disease (ESKD) or dialysis patients. We describe here a very rare case of Aspergillus Niger peritonitis in an ESKD patient on peritoneal dialysis (PD) receiving maintenance eculizumab therapy for atypical hemolytic uremic syndrome. Given that murine models with the same defect as that induced by eculizumab is vulnerable to invasive Aspergillosis, it is suggested that the fungal peritonitis in this patient was the result of the eculizumab therapy. PMID:24512095

Vellanki, Venkat S; Bargman, Joanne M

2014-05-01

295

Role of functional groups on Aspergillus niger biomass in the detoxification of hexavalent chromium.  

PubMed

Chromium (VI) contamination is not uncommon, especially near industries involved in leather tanning, chrome painting, metal cleaning and processing, wood preservation and alloy preparation. The mutagenic and carcinogenic properties of Chromium (VI) necessitate effective remedial processes. Difficulties associated with chemical and physical techniques to remediate a Chromium (VI) contaminated site to EPA recommended level (50 ppm), in addition to higher costs involved, assert the need for bioremedial measures. Biosorption can be one such solution to clean up heavy metal contamination. The objective of this study was to examine the main aspects of a possible strategy for the removal of Chromium (VI), employing Aspergillus niger biomass. The roles played by amines, carboxylic acids, phosphates, in Chromium (VI) biosorption were studied. Amino and the carboxy groups on the fungal cell wall play an important role in sorption. However, the role of carboxy group was far less than amino group. Surface adsorption of Chromium (VI) was also seen by scanning electron microscopy (SEM) thus indicating involvement of ion-exchange and surface adsorption mechanism in removal of Chromium (VI) ions. PMID:21117413

Narvekar, Sneha; Vaidya, Varsha K

2009-10-01

296

Metabolism of 2-ketoaldehydes in mold: purification and characterization of glyoxalase I from Aspergillus niger.  

PubMed

Glyoxalase I catalyzing the conversion of methylglyoxal into S-lactoylglutathione in the presence of glutathione was purified approximately 1,400-fold with 2.9% activity yield from mold, Aspergillus niger. The enzyme consisted of a single polypeptide chain with a relative molecular weight of 36,000 on both SDS-polyacrylamide gel electrophoresis and Sephadex G-150 gel filtration. The enzyme was most active at pH 7.0, 35-37 degrees C. Among the various aldehydes tested, the enzyme was active on methylglyoxal and 4,5-dioxovalerate with Km values of 1.25 and 0.87 mM, respectively. The activity of the enzyme was completely inhibited by Zn2+ at 0.5 mM. An equimolar amount of EDTA (0.5 mM) protected the enzyme from inactivation by Zn2+. EDTA competitively (K1 = 1.3 mM) inhibited the activity of the enzyme. Fe2+ was a potent activator for the enzyme, the activation being approximately 2.4-fold at 0.5 mM. PMID:3123469

Inoue, Y; Rhee, H; Watanabe, K; Murata, K; Kimura, A

1987-09-01

297

The Transcriptional Activator XlnR Regulates Both Xylanolytic and Endoglucanase Gene Expression in Aspergillus niger  

PubMed Central

The expression of genes encoding enzymes involved in xylan degradation and two endoglucanases involved in cellulose degradation was studied at the mRNA level in the filamentous fungus Aspergillus niger. A strain with a loss-of-function mutation in the xlnR gene encoding the transcriptional activator XlnR and a strain with multiple copies of this gene were investigated in order to define which genes are controlled by XlnR. The data presented in this paper show that the transcriptional activator XlnR regulates the transcription of the xlnB, xlnC, and xlnD genes encoding the main xylanolytic enzymes (endoxylanases B and C and ?-xylosidase, respectively). Also, the transcription of the genes encoding the accessory enzymes involved in xylan degradation, including ?-glucuronidase A, acetylxylan esterase A, arabinoxylan arabinofuranohydrolase A, and feruloyl esterase A, was found to be controlled by XlnR. In addition, XlnR also activates transcription of two endoglucanase-encoding genes, eglA and eglB, indicating that transcriptional regulation by XlnR goes beyond the genes encoding xylanolytic enzymes and includes regulation of two endoglucanase-encoding genes.

van Peij, Noel N. M. E.; Gielkens, Marco M. C.; de Vries, Ronald P.; Visser, Jaap; de Graaff, Leo H.

1998-01-01

298

Exploring Sequence Characteristics Related to High-Level Production of Secreted Proteins in Aspergillus niger  

PubMed Central

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.

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

2012-01-01

299

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

SciTech Connect

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

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

1985-04-01

300

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

PubMed Central

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

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

2009-01-01

301

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

302

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

NASA Astrophysics Data System (ADS)

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

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

2013-08-01

303

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

PubMed

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

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

2013-08-01

304

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

2008-09-10

305

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

306

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

2013-06-01

307

Gene encoding a novel invertase from a xerophilic Aspergillus niger strain and production of the enzyme in Pichia pastoris.  

PubMed

?-Fructofuranosidases or invertases (EC 3.2.1.26) are enzymes that are widely used in the food industry, where fructose is preferred over sucrose, because it is sweeter and does not crystallize easily. Since Aspergillus niger GH1, an xerophilic fungus from the Mexican semi-desert, has been reported to be an invertase producer, and because of the need for new enzymes with biotechnological applications, in this work, we describe the gene and amino acid sequence of the invertase from A. niger GH1, and the use of a synthetic gene to produce the enzyme in the methylotrophic yeast Pichia pastoris. In addition, the produced invertase was characterized biochemically. The sequence of the invertase gene had a length of 1770bp without introns, encodes a protein of 589 amino acids, and presented an identity of 93% and 97% with invertases from Aspergillus kawachi IFO 4308 and A. niger B60, respectively. A 4.2L culture with the constructed recombinant P. pastoris strain showed an extracellular and periplasmic invertase production at 72h induction of 498 and 3776 invertase units (U), respectively, which corresponds to 1018U/L of culture medium. The invertase produced had an optimum pH of 5.0, optimum temperature of 60°C, and specific activity of 3389U/mg protein, and after storage for 96h at 4°C showed 93.7% of its activity. This invertase could be suitable for producing inverted sugar used in the food industry. PMID:25039056

Veana, Fabiola; Fuentes-Garibay, José Antonio; Aguilar, Cristóbal Noé; Rodríguez-Herrera, Raúl; Guerrero-Olazarán, Martha; Viader-Salvadó, José María

2014-09-01

308

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

309

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

PubMed Central

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

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

2007-01-01

310

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

311

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

PubMed

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

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

2006-11-15

312

Tandem mass spectrometric analysis of aspergillus niger pectin methylesterase: mode of action on fully methyl-esterified oligogalacturonates.  

PubMed Central

The substrate specificity and the mode of action of Aspergillus niger pectin methylesterase (PME) was determined using both fully methyl-esterified oligogalacturonates with degrees of polymerization (DP) 2-6 and chemically synthesized monomethyl trigalacturonates. The enzymic activity on the different substrates and a preliminary characterization of the reaction products were performed by using high-performance anion-exchange chromatography at neutral pH. Electrospray ionization tandem MS (ESI-MS/MS) was used to localize the methyl esters on the (18)O-labelled reaction products during the course of the enzymic reaction. A. niger PME is able to hydrolyse the methyl esters of fully methyl-esterified oligogalacturonates with DP 2, and preferentially hydrolyses the methyl esters located on the internal galacturonate residues, followed by hydrolysis of the methyl esters towards the reducing end. This PME is unable to hydrolyse the methyl ester of the galacturonate moiety at the non-reducing end.

Kester, H C; Benen, J A; Visser, J; Warren, M E; Orlando, R; Bergmann, C; Magaud, D; Anker, D; Doutheau, A

2000-01-01

313

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

2011-10-01

314

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

PubMed Central

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

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

2014-01-01

315

Overexpression and functional characterization of an Aspergillus niger phytase in the fat body of transgenic silkworm, Bombyx mori.  

PubMed

In a previous study, we isolated 1,119 bp of upstream promoter sequence from Bmlp3, a gene encoding a member of the silkworm 30 K storage protein family, and demonstrated that it was sufficient to direct fat body-specific expression of a reporter gene in a transgenic silkworm, thus highlighting the potential use of this promoter for both functional genomics research and biotechnology applications. To test whether the Bmlp3 promoter can be used to produce recombinant proteins in the fat body of silkworm pupae, we generated a transgenic line of Bombyx mori which harbors a codon-optimized Aspergillus niger phytase gene (phyA) under the control of the Bmlp3 promoter. Here we show that the Bmlp3 promoter drives high levels of phyA expression in the fat body, and that the recombinant phyA protein is highly active (99.05 and 54.80 U/g in fat body extracts and fresh pupa, respectively). We also show that the recombinant phyA has two optimum pH ranges (1.5-2.0 and 5.5-6.0), and two optimum temperatures (55 and 37 °C). The activity of recombinant phyA was lost after high-temperature drying, but treating with boiling water was less harmful, its residual activity was approximately 84 % of the level observed in untreated samples. These results offer an opportunity not only for better utilization of large amounts of silkworm pupae generated during silk production, but also provide a novel method for mass production of low-cost recombinant phytase using transgenic silkworms. PMID:24719047

Xu, Hanfu; Liu, Yaowen; Wang, Feng; Yuan, Lin; Wang, Yuancheng; Ma, Sanyuan; Beneš, Helen; Xia, QingYou

2014-08-01

316

A high-throughput method for screening of Aspergillus niger mutants with high transglycosylation activity by detecting non-fermentable reducing sugar  

Microsoft Academic Search

A novel high-throughput method was established for rapid screening of large numbers of Aspergillus niger mutants with high transglucosylation activity by exploiting that yeast can hardly hydrolyze isomaltooligosaccharides (IMO).\\u000a Supernatants of A. niger fermentation were incubated with Saccharomyces cerevisiae to remove glucose and maltose, and the remaining non-reducing sugars, which is positively correlated with the amount of IMO,\\u000a the products

Gui-guang ChenWei; Wei Li; Yun-kai Zhang; Yong-ling Qin; Kong-yang Wu; Zhi-qun Liang

2011-01-01

317

Improvement of xylanase production by Aspergillus niger XY-1 using response surface methodology for optimizing the medium composition*  

PubMed Central

Objective: To study the optimal medium composition for xylanase production by Aspergillus niger XY-1 in solid-state fermentation (SSF). Methods: Statistical methodology including the Plackett-Burman design (PBD) and the central composite design (CCD) was employed to investigate the individual crucial component of the medium that significantly affected the enzyme yield. Results: Firstly, NaNO3, yeast extract, urea, Na2CO3, MgSO4, peptone and (NH4)2SO4 were screened as the significant factors positively affecting the xylanase production by PBD. Secondly, by valuating the nitrogen sources effect, urea was proved to be the most effective and economic nitrogen source for xylanase production and used for further optimization. Finally, the CCD and response surface methodology (RSM) were applied to determine the optimal concentration of each significant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by multiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x 1 (urea)=0.163 (41.63 g/L), x 2 (Na2CO3)=?1.68 (2.64 g/L), x 3 (MgSO4)=1.338 (10.68 g/L) and the predicted xylanase value was 14374.6 U/g dry substrate. Using the optimized condition, xylanase production by Aspergillus niger XY-1 after 48 h fermentation reached 14637 U/g dry substrate with wheat bran in the shake flask. Conclusion: By using PBD and CCD, we obtained the optimal composition for xylanase production by Aspergillus niger XY-1 in SSF, and the results of no additional expensive medium and shortened fermentation time for higher xylanase production show the potential for industrial utilization.

Xu, Yao-xing; Li, Yan-li; Xu, Shao-chun; Liu, Yong; Wang, Xin; Tang, Jiang-wu

2008-01-01

318

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

319

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

320

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

321

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

SciTech Connect

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

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

1985-04-01

322

Partially esterified oligogalacturonides are the preferred substrates for pectin methylesterase of Aspergillus niger.  

PubMed

Investigations on the mode of action of Aspergillus niger pectin methylesterase (PME) towards differently C(6)- and C(1)-substituted oligogalacturonides (oligoGal p A) are described. De-esterification of methyl-esterified (un)saturated oligoGal p A proceeds via a specific pattern, depending on the degree of polymerization. Initially, a first methyl ester of the oligomer is hydrolysed, resulting in one free carboxyl group. Subsequently, this first product is preferred as a substrate and is de-esterified for a second time. This product is then accumulated and hereafter de-esterified further to the final product, i.e. oligoGal p A containing one methyl ester located at the non-reducing end residue for both saturated and unsaturated oligoGal p A, as found by post-source decay matrix-assisted laser-desorption/ionization-time-of-flight MS. The saturated hexamer is an exception to this: three methyl esters are removed very rapidly, instead of two methyl esters. When unsaturated oligoGal p A were used, the formation of the end product differed slightly, suggesting that the unsaturated bond at the non-reducing end influences the de-esterification process. In vivo, PME prefers methyl esters, but the enzyme appeared to be tolerant for other C(6)- and C(1)-substituents. Changing the type of ester (ethyl esterification) or addition of a methyl glycoside (C(1)) only reduced the activity or had no effect respectively. The specific product pattern was identical for all methyl- and ethyl-esterified oligoGal p A and methyl-glycosidated oligoGal p A, which strongly indicates that one or perhaps two non-esterified oligoGal p A are preferred in the active-site cleft. PMID:12589708

van Alebeek, Gert-Jan W M; van Scherpenzeel, Katrien; Beldman, Gerrit; Schols, Henk A; Voragen, Alphons G J

2003-05-15

323

Glycoprotein enzymes secreted by Aspergillus niger: purification and properties of alpha-glaactosidase.  

PubMed

An alpha-galactosidase (alpha-D-galactoside galactohydrolase [EC 3.2.1.22]) was purified to homogeneity from the culture filtrate of Aspergillus niger. The enzyme had an apparent molecular weight of 45,000 and was a glycoprotein. Radioactive enzyme was prepared by growing cells in [14C]fructose and this enzyme was used to prepare 14C-labeled glycopeptides. The glycopeptides emerged from Sephadex G-50 between stachyose and the glycopeptide from ovalbumin. Based on calibration of the column with various-sized dextran oligosaccharides, the glycopeptides appeared to have a molecular weight of 1,200 to 1,400. Analysis of the glycopeptide(s) indicated that it contained mannose and N-acetylglucosamine (GlcNAc) in an approximate ratio of 3 or 4 to 1. Assuming that there are two GlcNAc residues in the oligosaccharide and based on the molecular weight of the glycopeptide, the oligosaccharide probably contains eight to nine sugar residues. Alks probably attached to the protein by a GlcNAc leads to asparagine linkage. The purified alpha-galactosidase was most active on raffinose (Km = 5 x 10--4 M, Vmax = 3 mumol/min per mg of protein), but also showed good activity on p-nitrophenyl-alpha-D-galactoside ans somewhat less activity on stachyose and melibitol. The enzyme also hydrolyzed guar flour and locust bean gum, but did not attack the p-nitrophenyl glycosides of beta-galactose, alpha- or beta-glucose, or alpha- or beta-mannose. PMID:14112

Adya, S; Elbein, A D

1977-02-01

324

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

325

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

326

Crystal structure of Aspergillus niger isopullulanase, a member of glycoside hydrolase family 49.  

PubMed

An isopullulanase (IPU) from Aspergillus niger ATCC9642 hydrolyzes alpha-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 H(f) to cleave the N-linked oligosaccharides of IPU, and we here determined the unliganded and isopanose-complexed forms of IPU, both solved at 1.7-A resolution. IPU is composed of domains N and C joined by a short linker, with electron density maps for 11 or 12 N-acetylglucosamine residues per molecule. Domain N consists of 13 beta-strands and forms a beta-sandwich. Domain C, where the active site is located, forms a right-handed beta-helix, and the lengths of the pitches of each coil of the beta-helix are similar to those of GH49 dextranase and GH28 polygalacturonase. The entire structure of IPU resembles that of a GH49 enzyme, Penicillium minioluteum dextranase (Dex49A), despite a difference in substrate specificity. Compared with the active sites of IPU and Dex49A, the amino acid residues participating in subsites +2 and +3 are not conserved, and the glucose residues of isopanose bound to IPU completely differ in orientation from the corresponding glucose residues of isomaltose bound to Dex49A. The shape of the catalytic cleft characterized by the seventh coil of the beta-helix and a loop from domain N appears to be critical in determining the specificity of IPU for pullulan. PMID:18155243

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

2008-02-01

327

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

328

[Fermentation optimization by response surface methodology for enhanced production of beta-glucosidase of Aspergillus niger HDF05].  

PubMed

In order to obtain high beta-glucosidase productivity, we optimized the fermentation parameters for beta-glucosidase production by Aspergillus niger HDF05. First, we screened the important parameters by Plackeet-Burman design. Second, we used the path of steepest ascent to approach to the biggest response region of parameters affecting beta-glucosidase production. Then, we obtained the optimal parameters by central composite design and response surface analysis. We developed a quadratic polynomial equation for predicting beta-glucosidase production level. The results showed that the important parameters were temperature, packing volume, concentrations of wheat bran and (NH4)2SO4. The optimal fermentation parameters were as follows: temperature 28 degrees C, packing volume 71.4 mL/250 mL, wheat bran 36 g/L and (NH4)2SO4 5.5 g/L. Under the optimal conditions, we obtained the maximum enzyme activity of 60.06 U/mL, with an increase of 23.9% compared to the original fermentation parameters. During enzymatic hydrolysis of acid-pretreated corncob, addition of beta-glucosidase from Aspergillus niger HDF05 greatly reduced the inhibition caused by cellobiose, and the hydrolysis yield was improved from 66.7% to 80.4%. PMID:21650023

Ling, Hongzhi; Ge, Jingping; Ping, Wenxiang; Xu, Xiuhong

2011-03-01

329

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

2011-11-01

330

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

PubMed

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

Silva, Marceli Fernandes; Rigo, Diane; Mossi, Vinícius; Golunski, Simone; Kuhn, Graciele de Oliveira; Di Luccio, Marco; Dallago, Rogério; de Oliveira, Débora; Oliveira, J Vladimir; Treichel, Helen

2013-05-01

331

The antifungal efficacy of nano-metals supported TiO? 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 5 wt% nano Ag catalyst was 65 mg/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=0.475-0.966 h(-1)) were much higher than those in the absence of ozone (k=0.001-0.268 h(-1)). However, on the surface of TiO? 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

2013-10-15

332

Mathematical modelling and assessment of the pH homeostasis mechanisms in Aspergillus niger while in citric acid producing conditions.  

PubMed

In this work we introduce an extended model of the Aspergillus niger metabolism while in citrate production conditions. The model includes many recent findings related to various transport processes. It now considers a new information about the fructose uptake system and the proton and amino acids carriers between cytoplasm and the external medium. It also accounts for recent information about both the malate-citrate antiport between mitochondria and cytoplasm and the dihydrogen citrate ion excretion symport with protons. Finally, the model also accounts for new information about the glycerol-3-phosphate shuttle and pH buffering systems. Provided with this updated representation and after having assessed its quality and dynamic behaviour, we were able to explain the observed pH homoeostasis found in A. niger while in citrate producing conditions. The model also serves to enhance our comprehension of the molecular mechanisms operating in order to keep homoeostasis of pH in A. niger and other fungi, bacteria and yeast of biotechnological relevance. PMID:21549718

García, Jacqueline; Torres, Néstor

2011-08-01

333

Tamarind seed powder and palm kernel cake: two novel agro residues for the production of tannase under solid state fermentation by Aspergillus niger ATCC 16620  

Microsoft Academic Search

Palm kernel cake (PKC), the residue obtained after extraction of palm oil from oil palm seeds and tamarind seed powder (TSP) obtained after removing the fruit pulp from tamarind fruit pod were tested for the production of tannase under solid-state fermentation (SSF) using Aspergillus niger ATCC 16620. The fungal strain was grown on the substrates without any pretreatment. In PKC

A. Sabu; A. Pandey; M. Jaafar Daud; G. Szakacs

2005-01-01

334

Identification, characterization of levoglucosan kinase, and cloning and expression of levoglucosan kinase cDNA from Aspergillus niger CBX-209 in Escherichia coli  

Microsoft Academic Search

The first enzyme responsible for assimilating levoglucosan in Aspergillus niger CBX-209 was corroborated to be levoglucosan kinase that catalyzes the transfer of a phosphate group from ATP to levoglucosan to yield a glucose 6-phosphate in the presence of magnesium ion and ATP by FAB-mass spectrometric method combined with previous observations from HPLC and enzymological experiments. Levoglucosan kinase was purified to

Xuliang Zhuang; Hongxun Zhang

2002-01-01

335

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

PubMed Central

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

2013-01-01

336

Improved enzyme production by bio-pellets of Aspergillus niger: targeted morphology engineering using titanate microparticles.  

PubMed

The present study describes the design of bio-pellet morphologies of the industrial working horse Aspergillus niger strains in submerged culture. The novel approach recruits the intended addition of titanate microparticles (TiSiO(4), 8 µm) to the growth medium. As tested for two recombinant strains producing fructofuranosidase and glucoamylase, the enzyme titer by the titanate-enhanced cultures in shake flasks was increased 3.7-fold to 150 U/mL (for fructofuranosidase) and 9.5-fold to 190 U/mL (for glucoamylase) as compared to the control. This could be successfully utilized for improved enzyme production in stirred tank reactors. Stimulated by the particles, the achieved final glucoamylase activity of 1,080 U/mL (fed-batch) and 320 U/mL (batch) was sevenfold higher as compared to the conventional processes. The major reason for the enhanced production was the close association between the titanate particles and the fungal cells. Already below 2.5 g/L the micromaterial was found inside the pellets, including single particles embedded as 50-150 µm particle aggregates in the center resulting in core shell pellets. With increasing titanate levels the pellet size decreased from 1,700 µm (control) to 300 µm. Fluorescence based resolution of GFP expression revealed that the large pellets of the control were only active in a 200 µm surface layer. This matches with the critical penetration depth for nutrients and oxygen typically observed for fungal pellets. The biomass within the titanate derived fungal pellets, however, was completely active. This was due a reduced thickness of the biomass layer via smaller pellets as well as the core shell structure. Moreover, also the created loose inner pellet structure enabled a higher mass transfer and penetration depths for up to 500 µm. The creation of core-shell pellets has not been achieved previously by the addition of microparticles, for example, made of talc or alumina. Due to this, the present work opens further possibilities to use microparticles for tailor-made morphology design of filamentous fungi, especially for pellet based processes which have a long and strong industrial relevance for industrial production. PMID:21887774

Driouch, Habib; Hänsch, Robert; Wucherpfennig, Thomas; Krull, Rainer; Wittmann, Christoph

2012-02-01

337

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

PubMed Central

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

Papagianni, Maria

2006-01-01

338

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

SciTech Connect

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

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

2010-12-06

339

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

PubMed

The identity of nine clinical isolates recovered from Czech patients and presumptively identified as Aspergillus sp. section Candidi based on colony morphology was revised using sequences of ?-tubulin, calmodulin gene sequence, and internal transcribed spacer rDNA. Six isolates were from suspected and proven onychomycosis, one from otitis externa, and two associated with probable invasive aspergillosis. The results showed that one Aspergillus candidus isolate was the cause of otitis externa, and both isolates obtained from sputa of patients with probable invasive aspergillosis were reidentified as A. carneus (sect. Terrei) and A. flavus (sect. Flavi). Three isolates from nail scrapings were identified as A. tritici, a verified agent of nondermatophyte onychomycosis. One isolate from toenail was determined to be A. candidus and the two isolates belonged to a hitherto undescribed species, Aspergillus pragensis sp. nov. This species is well supported by phylogenetic analysis based on ?-tubulin and calmodulin gene and is distinguishable from other members of sect. Candidi by red-brown reverse on malt extract agar, slow growth on Czapek-Dox agar and inability to grow at 37°C. A secondary metabolite analysis was also provided with comparison of metabolite spectrum to other species. Section Candidi now encompasses five species for which a dichotomous key based on colony characteristics is provided. All clinical isolates were tested for susceptibilities to selected antifungal agents using the Etest and disc diffusion method. Overall sect. Candidi members are highly susceptible to common antifungals. PMID:24951723

Hubka, Vit; Lyskova, Pavlina; Frisvad, Jens C; Peterson, Stephen W; Skorepova, Magdalena; Kolarik, Miroslav

2014-08-01

340

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

PubMed

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

Almeida, E J R; Corso, C R

2014-10-01

341

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

342

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

343

Molecular and Chemical Characterization of the Biosynthesis of the 6-MSA-Derived Meroterpenoid Yanuthone D in Aspergillus niger.  

PubMed

Secondary metabolites in filamentous fungi constitute a rich source of bioactive molecules. We have deduced the genetic and biosynthetic pathway of the antibiotic yanuthone D from Aspergillus niger. Our analyses show that yanuthone D is a meroterpenoid derived from the polyketide 6-methylsalicylic acid (6-MSA). Yanuthone D formation depends on a cluster composed of ten genes including yanA and yanI, which encode a 6-MSA polyketide synthase and a previously undescribed O-mevalon transferase, respectively. In addition, several branching points in the pathway were discovered, revealing five yanuthones (F, G, H, I, and J). Furthermore, we have identified another compound (yanuthone X1) that defines a class of yanuthones that depend on several enzymatic activities encoded by genes in the yan cluster but that are not derived from 6-MSA. PMID:24684908

Holm, Dorte K; Petersen, Lene M; Klitgaard, Andreas; Knudsen, Peter B; Jarczynska, Zofia D; Nielsen, Kristian F; Gotfredsen, Charlotte H; Larsen, Thomas O; Mortensen, Uffe H

2014-04-24

344

Purification and Characterization of a ?-Glucosidase from Aspergillus niger and Its Application in the Hydrolysis of Geniposide to Genipin.  

PubMed

An extracellular ?-glucosidase from Aspergillus niger Au0847 was purified to homogeneity by precipitation with ammonium sulfate, anion exchange, and gel filtration. The purified protein was composed of two subunits with molecular masses of 110 and 120 kDa. Au0847 ?-glucosidase exhibited relatively high thermostability and pH stability, and its highest activity was obtained at 65°C and pH 4.6, respectively. As a potential metalloprotein, its enzymatic activity was potently stimulated by manganese ion and DTT. The ?-glucosidase displayed avid affinity and high catalytic efficiency for geniposide. Au0847 ?-glucosidase has potential value as an industrial enzyme for the hydrolysis of geniposide to genipin. PMID:24608563

Gong, Guohong; Zheng, Zhiming; Liu, Hui; Wang, Li; Diao, Jinshan; Wang, Peng; Zhao, Genhai

2014-06-28

345

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

2013-01-01

346

Sequential solid-state and submerged cultivation of Aspergillus niger on sugarcane bagasse for the production of cellulase.  

PubMed

Sequential solid-state and submerged cultivation with sugarcane bagasse as substrate for cellulase production by Aspergillus niger A12 was assessed by measuring endoglucanase activity. An unconventional pre-culture with an initial fungal growth phase under solid-state cultivation was followed by a transition to submerged fermentation by adding the liquid culture medium to the mycelium grown on solid substrate. For comparison, control experiments were conducted using conventional submerged cultivation. The cultures were carried out in shake flasks and in a 5-L bubble column bioreactor. An endoglucanase productivity of 57 ± 13 IU/L/h was achieved in bubble column cultivations prepared using the new method, representing an approximately 3-fold improvement compared to conventional submerged fermentation. Therefore, the methodology proposed here of a sequential fermentation process offers a promising alternative for cellulase production. PMID:22409979

Cunha, F M; Esperança, M N; Zangirolami, T C; Badino, A C; Farinas, C S

2012-05-01

347

Treatment of APMP pulping effluent based on aerobic fermentation with Aspergillus niger and post-coagulation/flocculation.  

PubMed

A novel two-stage biological/flocculation process was developed for treating the pulping effluent from the alkaline peroxide mechanical pulping (APMP) process. In the first biological stage, the aerobic fermentation by using Aspergillus niger can decrease the chemical oxygen demand (COD) by about 60% while producing about 7 g/l of solid biomass. In the second stage (post-coagulation/flocculation), the residual COD, turbidity and color, can be further decreased by using alum and polyacrylamide (PAM). The overall removal efficiencies of COD, color and turbidity from the APMP pulping effluent by the above two-stage biological-coagulation/flocculation process were 93%, 92% and 99%, respectively, under the conditions studied. PMID:21315583

Liu, Tingzhi; He, Zhibin; Hu, Huiren; Ni, Yonghao

2011-04-01

348

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

PubMed Central

Silver Nanoparticles (AgNPs), the real silver bullet, are known to have good antibacterial properties against pathogenic microorganisms. In the present study AgNPs were prepared from extracellular filtrate of Aspergillus niger. Characterization of AgNPs by UV-Vis spectrum reveals specific surface plasmon resonance at peak 416?nm; TEM photographs revealed the size of the AgNPs to be 20–55?nm. Average diameter of the produced AgNPs was found to be 73?nm with a zeta potential that was ?24?mV using Malvern Zetasizer. SEM micrographs showed AgNPs to be spherical with smooth morphology. EDS revealed the presence of pure metallic AgNPs along with carbon and oxygen signatures. Of the different concentrations (0, 2.5, 5, 10, and 15??g/mL) used 10??g/mL were sufficient to inhibit 107?CFU/mL of E. coli. ROS production was measured using DCFH-DA method and the the free radical generation effect of AgNPs on bacterial growth inhibition was investigated by ESR spectroscopy. This paper not only deals with the damage inflicted on microorganisms by AgNPs but also induces cell death through the production of ROS released by AgNPs and also growth kinetics of E. coli supplemented with AgNPs produced by A. niger.

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

2014-01-01

349

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

PubMed

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

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

2010-09-01

350

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

PubMed Central

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

2014-01-01

351

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

PubMed

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 was fairly stable at 30 degrees C with a deactivation constant (k (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 (d) = 0.008 h(-1) and half-life of 87 h at 40 degrees C. Another advantage of this enzyme was its high chemoselectivity, i.e., selective transformation of nitriles into carboxylic acids, while the amide formed a high ratio of A. niger K10 nitrilase product. High conversion rates (>90%) were maintained for about 52 h using the nitrilase from F. solani O1 immobilized in cross-linked enzyme aggregates (CLEAs). The purity of isonicotinic acid was increased from 98% to >99.9% by using two CSMRs connected in series, the first one containing the F. solani O1 nitrilase and the second the amidase from Rhodococcus erythropolis A4 (both enzymes as CLEAs), the amidase hydrolyzing the by-product isonicotinamide. PMID:19554325

Malandra, Anna; Cantarella, Maria; Kaplan, Ondrej; Vejvoda, Vojtech; Uhnáková, Bronislava; Stepánková, Barbora; Kubác, David; Martínková, Ludmila

2009-11-01

352

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

PubMed

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

Kuivanen, Joosu; Dantas, Hugo; Mojzita, Dominik; Mallmann, Edgar; Biz, Alessandra; Krieger, Nadia; Mitchell, David; Richard, Peter

2014-01-01

353

Functional characterization of Rho GTPases in Aspergillus niger uncovers conserved and diverged roles of Rho proteins within filamentous fungi.  

PubMed

Rho GTPases are signalling molecules regulating morphology and multiple cellular functions including metabolism and vesicular trafficking. To understand the connection between polarized growth and secretion in the industrial model organism Aspergillus niger, we investigated the function of all Rho family members in this organism. We identified six Rho GTPases in its genome and used loss-of-function studies to dissect their functions. While RhoA is crucial for polarity establishment and viability, RhoB and RhoD ensure cell wall integrity and septum formation respectively. RhoC seems to be dispensable for A. niger. RacA governs polarity maintenance via controlling actin but not microtubule dynamics, which is consistent with its localization at the hyphal apex. Both deletion and dominant activation of RacA (Rac(G18V)) provoke an actin localization defect and thereby loss of polarized tip extension. Simultaneous deletion of RacA and CftA (Cdc42) is lethal; however, conditional overexpression of RacA in this strain can substitute for CftA, indicating that both proteins concertedly control actin dynamics. We finally identified NoxR as a RacA-specific effector, which however, is not important for apical dominance as reported for A. nidulans but for asexual development. Overall, the data show that individual Rho GTPases contribute differently to growth and morphogenesis within filamentous fungi. PMID:21205013

Kwon, Min Jin; Arentshorst, Mark; Roos, Eelke D; van den Hondel, Cees A M J J; Meyer, Vera; Ram, Arthur F J

2011-03-01

354

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

355

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; Bessičre, J M; Fonvieille, J L; Dargent, R

2001-01-01

356

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

PubMed Central

Arsenic contamination of groundwater sources is a major issue worldwide, since exposure to high levels of arsenic has been linked to a variety of health problems. Effective methods of detection are thus greatly needed as preventive measures. In an effort to develop a fungal biosensor for arsenic, we first identified seven putative arsenic metabolism and transport genes in Aspergillus niger, a widely used industrial organism that is generally regarded as safe (GRAS). Among the genes tested for RNA expression in response to arsenate, acrA, encoding a putative plasma membrane arsenite efflux pump, displayed an over 200-fold increase in gene expression in response to arsenate. We characterized the function of this A. niger protein in arsenic efflux by gene knockout and confirmed that AcrA was located at the cell membrane using an enhanced green fluorescent protein (eGFP) fusion construct. Based on our observations, we developed a putative biosensor strain containing a construct of the native promoter of acrA fused with egfp. We analyzed the fluorescence of this biosensor strain in the presence of arsenic using confocal microscopy and spectrofluorimetry. The biosensor strain reliably detected both arsenite and arsenate in the range of 1.8 to 180 ?g/liter, which encompasses the threshold concentrations for drinking water set by the World Health Organization (10 and 50 ?g/liter).

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

2012-01-01

357

Effect of Matricaria chamomilla L. flower essential oil on the growth and ultrastructure of Aspergillus niger van Tieghem.  

PubMed

The antifungal activity of Matricaria chamomilla L. flower essential oil was evaluated against Aspergillus niger with the emphasis on the plant's mode of action at the electron microscopy level. A total of 21 compounds were identified in the plant oil using gas chromatography/mass spectrometry (GC/MS) accounting for 92.86% of the oil composition. The main compounds identified were alpha-bisabolol (56.86%), trans-trans-farnesol (15.64%), cis-beta-farnesene (7.12%), guaiazulene (4.24%), alpha-cubebene (2.69%), alpha-bisabolol oxide A (2.19%) and chamazulene (2.18%). In the bioassay, A. niger was cultured on Potato Dextrose Broth medium in 6-well microplates in the presence of serial two fold concentrations of plant oil (15.62 to 1000 microg/mL) for 96 h at 28 degrees C. Based on the results obtained, A. niger growth was inhibited dose dependently with a maximum of approximately 92.50% at the highest oil concentration. A marked retardation in conidial production by the fungus was noticed in relation to the inhibition of hyphal growth. The main changes of hyphae observed by transmission electron microscopy were disruption of cytoplasmic membranes and intracellular organelles, detachment of plasma membrane from the cell wall, cytoplasm depletion, and complete disorganization of hyphal compartments. In scanning electron microscopy, swelling and deformation of hyphal tips, formation of short branches, and collapse of entire hyphae were the major changes observed. Morphological alterations might be due to the effect on cell permeability through direct interaction of M. chamomilla essential oil with the fungal plasma membrane. These findings indicate the potential of M. chamomilla L. essential oil in preventing fungal contamination and subsequent deterioration of stored food and other susceptible materials. PMID:20385420

Tolouee, Marziyeh; Alinezhad, Soheil; Saberi, Reza; Eslamifar, Ali; Zad, Seyed Javad; Jaimand, Kamkar; Taeb, Jaleh; Rezaee, Mohammad-Bagher; Kawachi, Masanobu; Shams-Ghahfarokhi, Masoomeh; Razzaghi-Abyaneh, Mehdi

2010-05-15

358

Growth performance of broiler chickens fed diets containing shea nut (Vitellaria paradoxa, Gaertn.) meal fermented with Aspergillus niger.  

PubMed

Shea nut meal is a by-product of the shea fat industry in West Africa. The objective was to determine the effect of shea nut meal fermentation using Aspergillus niger on growth performance of broiler chickens. An expeller shea nut meal was fermented in a closed plastic container for 8 d after the addition of 0.25 g of A. niger spores per kg of shea nut meal in 2 parts of water. Each of the 2 shea nut meal samples (the unfermented and fermented meals) replaced wheatfeed in a control diet at 100 g/kg and fed to 128 Ross 308 male broiler chickens (22 to 36 d). There were 8 replicates per diet (2 shea nut meal samples and the control wheatfeed diet) and 4 birds per replicate in cages (0.6 m x 0.6 m x 0.9 m). Analysis of variance of data was used to compare the treatment means. The fermentation method reduced the concentrations of total soluble phenolics (21.9%), bound plus soluble proanthocyanidins (34.5%), soluble proanthocyanidins (24.7%), and hydrolysable tannins (52.9%) in the shea nut meal. Broilers fed the fermented meal exhibited higher (P < 0.001) growth performance than those fed the unfermented meal. However, the growth performance of broilers fed each of the shea nut meal-based diets was lower (P < 0.001) than that of broilers fed the control diet. Mean live weight gain of broilers fed the fermented shea nut meal diet was 82% of that of broilers fed the control diet. The fermentation of shea nut meal using A. niger has the potential to improve the nutritive value of shea nut meal for poultry, but requires further development. PMID:18753445

Dei, H K; Rose, S P; Mackenzie, A M; Amarowicz, R

2008-09-01

359

[Cloning and expression of Aspergillus niger glucose oxidase gene in methylotrophic yeast].  

PubMed

The DNA fragment encoding A. niger glucose oxidase was amplified by PCR using A. niger genomic DNA as template, and was cloned into vector of pPIC9 for expression in Pichia pastoris. When transformed into methylotrophic yeast Pichia pastoris GS115, The constructed plasmid pPICGOD1 directed the synthesis and secretion of functionally active GOD. After induction in MM medium for 4 days, the GOD activity in the medium reached 30-40 u/mL. SDS-PAGE revealed that recombinant yeast GOD was expressed up to 60%-70% of the total soluble protein, and the secreted GOD could be purified to electrophoretic homogeneity with one purification step using Q Sepharose Fast Flow ion exchange chromatography. The recombinant yeast GOD had very high catalytic activity, showed about 1.6-fold increase of specific activity over the commercial A. niger GOD. Kinetic analysis clearly demonstrated that recombinant yeast GOD showed similar substrate affinity for glucose to A. niger GOD, but the turnover number of the GOD from yeast was determined to be much higher than that of A. niger GOD. In addition, the linear range of glucose electrode made with recombinant yeast GOD was efficiently widened due to the high catalytic activity of yeast GOD. PMID:11702696

Zhou, Y F; Zhang, X E; Liu, H; Zhang, C G; Cass, A E

2001-07-01

360

Influence of acarbose and maltose on the reactivity of individual tryptophanyl residues in glucoamylase from aspergillus niger  

Microsoft Academic Search

Tryptophanyl residues of A niger glucoamylase G2 (EC 3.2.1.3) involved in substrate and inhibitor binding have been identified\\u000a following N-bromosuccinimide (NBS) treatment in the presence and absence of protective ligands. Appropriate proteolytic cleavages\\u000a of the glucoamylase derivatives enabled isolation of individual peptide fragments containing the 15 thytophan positions and\\u000a the extent of tryptophan oxidation was measured employing normal and 2nd

Birte Svensson; Anthony J. Clarke; Ib Svendsen

1986-01-01

361

Overexpression of a modified 6-phosphofructo-1-kinase results in an increased itaconic acid productivity in Aspergillus niger.  

PubMed

A modified 6-phosphofructo-1-kinase was expressed in a citrate producing Aspergillus niger strain in combination with cis-aconitate decarboxylase from Aspergillus terreus to study the effect on the production of itaconic acid. The modified pfkA gene was also expressed in combination with the itaconic acid biosynthetic cluster from A. terreus, which consists of cis-aconitate decarboxylase cadA, a putative mitochondrial transporter mttA and a putative plasmamembrane transporter mfsA. The combined expression of pfkA and cadA resulted in increased citrate levels, but did not show increased itaconic acid levels. The combined expression of pfkA with the itaconic acid biosynthetic cluster resulted in significantly increased itaconic acid production at earlier time points. Also the itaconic acid productivity increased significantly. The maximum itaconic acid productivity that was reached under these conditions was 0.15 g/L/h, which is only a factor 17 lower than the 2.5 g/L/h that according to the US Department of Energy should be achieved to have an economically feasible production process. PMID:24034235

van der Straat, Laura; Tamayo-Ramos, Juan A; Schonewille, Tom; de Graaff, Leo H

2013-01-01

362

Overexpression of a modified 6-phosphofructo-1-kinase results in an increased itaconic acid productivity in Aspergillus niger  

PubMed Central

A modified 6-phosphofructo-1-kinase was expressed in a citrate producing Aspergillus niger strain in combination with cis-aconitate decarboxylase from Aspergillus terreus to study the effect on the production of itaconic acid. The modified pfkA gene was also expressed in combination with the itaconic acid biosynthetic cluster from A. terreus, which consists of cis-aconitate decarboxylase cadA, a putative mitochondrial transporter mttA and a putative plasmamembrane transporter mfsA. The combined expression of pfkA and cadA resulted in increased citrate levels, but did not show increased itaconic acid levels. The combined expression of pfkA with the itaconic acid biosynthetic cluster resulted in significantly increased itaconic acid production at earlier time points. Also the itaconic acid productivity increased significantly. The maximum itaconic acid productivity that was reached under these conditions was 0.15 g/L/h, which is only a factor 17 lower than the 2.5 g/L/h that according to the US Department of Energy should be achieved to have an economically feasible production process.

2013-01-01

363

Aspergillus brasiliensis sp. nov., a biseriate black Aspergillus species with world-wide distribution.  

PubMed

A novel species, Aspergillus brasiliensis sp. nov., is described within Aspergillus section Nigri. This species can be distinguished from other black aspergilli based on intergenic transcribed region, beta-tubulin and calmodulin gene sequences, by amplified fragment length polymorphism analysis and by extrolite profiles. A. brasiliensis isolates produced naphtho-gamma-pyrones, tensidol A and B and pyrophen in common with Aspergillus niger and Aspergillus tubingensis, but also several unique compounds, justifying their treatment as representing a separate species. None of the isolates were found to produce ochratoxin A, kotanins, funalenone or pyranonigrins. The novel species was most closely related to A. niger, and was isolated from soil from Brazil, Australia, USA and The Netherlands, and from grape berries from Portugal. The type strain of Aspergillus brasiliensis sp. nov. is CBS 101740(T) (=IMI 381727(T)=IBT 21946(T)). PMID:17684283

Varga, János; Kocsubé, Sándor; Tóth, Beáta; Frisvad, Jens C; Perrone, Giancarlo; Susca, Antonia; Meijer, Martin; Samson, Robert A

2007-08-01

364

Production of tannase by Aspergillus niger Aa20 in submerged and solid-state fermentation: influence of glucose and tannic acid  

Microsoft Academic Search

  Tannase production by Aspergillus niger Aa-20 was studied in submerged (SmF) and solid-state (SSF) fermentation systems with different tannic acid and glucose concentrations.\\u000a Tannase activity and productivity were at least 2.5 times higher in SSF than in SmF. Addition of high tannic acid concentrations\\u000a increased total tannase activity in SSF, while in SmF it was decreased. In SmF, total tannase

C N Aguilar; C Augur; E Favela-Torres; G Viniegra-González

2001-01-01

365

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

366

Screening and identification of the levoglucosan kinase gene ( lgk) from Aspergillus niger by LC-ESI-MS\\/MS and RT-PCR  

Microsoft Academic Search

A protein of 75,000 Daltons with levoglucosan kinase activity was purified from Aspergillus niger. After in-gel digestion by trypsin, a 14-mer peptide was sequenced and analyzed by LC-ESI-MS\\/MS. Using a primer derived from the 14-mer peptide in combination with Oligo-(dT)18, a cDNA fragment was obtained by RT-PCR. A search of the GenBank database indicated that the protein had not been

Hui-jun Xie; Xu-liang Zhuang; Hong-xun Zhang; Zhi-hui Bai; Hong-yan Qi

2005-01-01

367

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

368

Proteome analysis of Aspergillus niger: Lactate added in starch-containing medium can increase production of the mycotoxin fumonisin B2 by modifying acetyl-CoA metabolism  

PubMed Central

Background Aspergillus niger is a filamentous fungus found in the environment, on foods and feeds and is used as host for production of organic acids, enzymes and proteins. The mycotoxin fumonisin B2 was recently found to be produced by A. niger and hence very little is known about production and regulation of this metabolite. Proteome analysis was used with the purpose to reveal how fumonisin B2 production by A. niger is influenced by starch and lactate in the medium. Results Fumonisin B2 production by A. niger was significantly increased when lactate and starch were combined in the medium. Production of a few other A. niger secondary metabolites was affected similarly by lactate and starch (fumonisin B4, orlandin, desmethylkotanin and pyranonigrin A), while production of others was not (ochratoxin A, ochratoxin alpha, malformin A, malformin C, kotanin, aurasperone B and tensidol B). The proteome of A. niger was clearly different during growth on media containing 3% starch, 3% starch + 3% lactate or 3% lactate. The identity of 59 spots was obtained, mainly those showing higher or lower expression levels on medium with starch and lactate. Many of them were enzymes in primary metabolism and other processes that affect the intracellular level of acetyl-CoA or NADPH. This included enzymes in the pentose phosphate pathway, pyruvate metabolism, the tricarboxylic acid cycle, ammonium assimilation, fatty acid biosynthesis and oxidative stress protection. Conclusions Lactate added in a medium containing nitrate and starch can increase fumonisin B2 production by A. niger as well as production of some other secondary metabolites. Changes in the balance of intracellular metabolites towards a higher level of carbon passing through acetyl-CoA and a high capacity to regenerate NADPH during growth on medium with starch and lactate were found to be the likely cause of this effect. The results lead to the hypothesis that fumonisin production by A. niger is regulated by acetyl-CoA.

2009-01-01

369

Indoloditerpenes from an algicolous isolate of Aspergillus oryzae.  

PubMed

Two new indoloditerpene derivatives asporyzin A (1) and asporyzin B (2), one new indoloditerpene asporyzin C (3), and three known related indoloditerpenes JBIR-03 (4), emindole SB (5), and emeniveol (6) were isolated from an endophytic fungus Aspergillus oryzae, isolated from the marine red alga Heterosiphonia japonica. Their structures were unambiguously established by spectroscopic techniques. In addition, all the isolates were evaluated preliminarily for insecticidal and antimicrobial activities in order to probe into their chemical defensive function. Compound 4 was more active against brine shrimp than the others, and 3 possessed potent activity against Escherichia coli. PMID:20797856

Qiao, Ming-Feng; Ji, Nai-Yun; Liu, Xiang-Hong; Li, Ke; Zhu, Qing-Mei; Xue, Qin-Zhao

2010-10-01

370

Production and characterization of in planta transiently produced polygalacturanase from Aspergillus niger and its fusions with hydrophobin or ELP tags  

PubMed Central

Background Pectinases play an important role in plant cell wall deconstruction and have potential in diverse industries such as food, wine, animal feed, textile, paper, fuel, and others. The demand for such enzymes is increasing exponentially, as are the efforts to improve their production and to implement their use in several industrial processes. The goal of this study was to examine the potential of producing polygalacturonase I from Aspergillus niger in plants and to investigate the effects of subcellular compartmentalization and protein fusions on its accumulation and activity. Results Polygalacturonase I from Aspergillus niger (AnPGI) was transiently produced in Nicotiana benthamiana by targeting it to five different cellular compartments: apoplast, endoplasmic reticulum (ER), vacuole, chloroplast and cytosol. Accumulation levels of 2.5%, 3.0%, and 1.9% of total soluble protein (TSP) were observed in the apoplast, ER, and vacuole, respectively, and specific activity was significantly higher in vacuole-targeted AnPGI compared to the same enzyme targeted to the ER or apoplast. No accumulation was found for AnPGI when targeted to the chloroplast or cytosol. Analysis of AnPGI fused with elastin-like polypeptide (ELP) revealed a significant increase in the protein accumulation level, especially when targeted to the vacuole where the protein doubles its accumulation to 3.6% of TSP, while the hydrophobin (HFBI) fusion impaired AnPGI accumulation and both tags impaired activity, albeit to different extents. The recombinant protein showed activity against polygalacturonic acid with optimum conditions at pH 5.0 and temperature from 30 to 50°C, depending on its fusion. In vivo analysis of reducing sugar content revealed a higher release of reducing sugars in plant tissue expressing recombinant AnPGI compared to wild type N. benthamiana leaves. Conclusion Our results demonstrate that subcellular compartmentalization of enzymes has an impact on both the target protein accumulation and its activity, especially in the case of proteins that undergo post-translational modifications, and should be taken into consideration when protein production strategies are designed. Using plants to produce heterologous enzymes for the degradation of a key component of the plant cell wall could reduce the cost of biomass pretreatment for the production of cellulosic biofuels.

2014-01-01

371

Antifungal Activities of Posaconazole, Ravuconazole, and Voriconazole Compared to Those of Itraconazole and Amphotericin B against 239 Clinical Isolates of Aspergillus spp. and Other Filamentous Fungi: Report from SENTRY Antimicrobial Surveillance Program, 2000  

PubMed Central

Posaconazole, ravuconazole, and voriconazole are new triazole derivatives that possess potent, broad-spectrum antifungal activity. We evaluated the in vitro activity of these investigational triazoles compared with that of itraconazole and amphotericin B against 239 clinical isolates of filamentous fungi from the SENTRY Program, including Aspergillus spp. (198 isolates), Fusarium spp. (7 isolates), Penicillium spp. (19 isolates), Rhizopus spp. (4 isolates), Mucor spp. (2 isolates), and miscellaneous species (9 isolates). The isolates were obtained from 16 different medical centers in the United States and Canada between January and December 2000. In vitro susceptibility testing was performed using the microdilution broth method outlined in the National Committee for Clinical Laboratory Standards M38-P document. Overall, posaconazole was the most active compound, inhibiting 94% of isolates at a MIC of ?1 ?g/ml, followed by voriconazole (91%), amphotericin B (89%), ravuconazole (88%), and itraconazole (70%). All three new triazoles demonstrated excellent activity (MIC, ?1 ?g/ml) against Aspergillus spp. (114 Aspergillus fumigatus, 22 Aspergillus niger, 13 Aspergillus flavus, 9 Aspergillus versicolor, 8 Aspergillus terreus, and 32 Aspergillus spp.): posaconazole (98%), voriconazole (98%), ravuconazole (92%), amphotericin B (89%), and itraconazole (72%). None of the triazoles were active against Fusarium spp. (MIC at which 50% of the isolates tested were inhibited [MIC50], >8 ?g/ml) or Mucor spp. (MIC50, >8 ?g/ml). Posaconazole and ravuconazole were more active than voriconazole against Rhizopus spp. (MIC50, 1 to 2 ?g/ml versus >8 ?g/ml, respectively). Based on these results, all three new triazoles exhibited promising activity against Aspergillus spp. and other less commonly encountered isolates of filamentous fungi. The clinical value of these in vitro data remains to be seen, and in vitro-in vivo correlation is needed for both new and established antifungal agents. Surveillance efforts should be expanded in order to monitor the spectrum of filamentous fungal pathogens and their in vitro susceptibility as these new antifungal agents are introduced into clinical use.

Pfaller, M. A.; Messer, S. A.; Hollis, R. J.; Jones, R. N.

2002-01-01

372

Cloning and characterization of a tyrosinase gene from the white-rot fungus Pycnoporus sanguineus, and overproduction of the recombinant protein in Aspergillus niger.  

PubMed

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 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 of biotechnological interest, under the control of the glyceraldehyde-3-phosphate-dehydrogenase promoter as strong and constitutive promoter. The glucoamylase preprosequence of A. niger was used to target the secretion. This construction enabled the production of recombinant tyrosinase in the extracellular medium of A. niger. The identity of the purified recombinant protein was confirmed by N-terminal amino acid sequencing. The maturation process was shown to be effective in A. niger, and the recombinant enzyme was fully active, with a molecular mass of 45 kDa. The best transformant obtained, A. niger D15#26-e, produced extracellular tyrosinase activities of 534 and 1,668 U l(-1) for monophenolase and diphenolase, respectively, which corresponded to a protein yield of ca. 20 mg l(-1). PMID:16151802

Halaouli, Sonia; Record, Eric; Casalot, Laurence; Hamdi, Moktar; Sigoillot, Jean-Claude; Asther, Marcel; Lomascolo, Anne

2006-05-01

373

Effects of promoters on the enhancement of pectin methyl esterase expression in Aspergillus niger  

Microsoft Academic Search

Summary A pectin methylesterase-encoding gene (pmeA)_has been cloned and transformed intoA. niger wild-type NRRL3. Transformants produced 20-fold more PME than the host strain. For studying the effects of different promoters on thepmeA expression two novel plasmids were constructed, in which thepmeA promoter was replaced by efficient promoters such as theA. nidulans glyceraldehyde-3-phosphate dehydrogenase (pK45) or theA. oryzae a-amylase (pK61) promoter.

N. Q. Khanh; K. Leidinger; H. Albrecht; E. Ruttkowski; M. Gottschalk

1992-01-01

374

Production of cellulases from Aspergillus niger NS-2 in solid state fermentation on agricultural and kitchen waste residues.  

PubMed

Various agricultural and kitchen waste residues were assessed for their ability to support the production of a complete cellulase system by Aspergillus niger NS-2 in solid state fermentation. Untreated as well as acid and base-pretreated substrates including corn cobs, carrot peelings, composite, grass, leaves, orange peelings, pineapple peelings, potato peelings, rice husk, sugarcane bagasse, saw dust, wheat bran, wheat straw, simply moistened with water, were found to be well suited for the organism's growth, producing good amounts of cellulases after 96 h without the supplementation of additional nutritional sources. Yields of cellulases were higher in alkali treated substrates as compared to acid treated and untreated substrates except in wheat bran. Of all the substrates tested, wheat bran appeared to be the best suited substrate producing appreciable yields of CMCase, FPase and ?-glucosidase at the levels of 310, 17 and 33 U/g dry substrate respectively. An evaluation of various environmental parameters demonstrated that appreciable levels of cellulases could be produced over a wide range of temperatures (20-50 °C) and pH levels (3.0-8.0) with a 1:1.5 to 1:1.75 substrate to moisture ratio. PMID:22503148

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

2012-07-01

375

A study of the protein secretory pathway of Aspergillus niger using a glucoamylase-GFP fusion protein.  

PubMed

The effect of various treatments that block protein secretion was visualized in Aspergillus niger using a strain expressing a glucoamylase-GFP fusion protein. Cold shock caused the retention of the fusion protein in a reticulate network (ER) with brighter nodes that may represent Golgi bodies. Treatment of germlings with brefeldin A (BFA) also initially caused accumulation within the ER but prolonged exposure led to the formation and targeting of the fusion protein to vacuoles from the ER. Disruption of actin with cytochalasin A initially led to a faint diffuse accumulation and ultimately to the formation of aggregated bodies which were not vacuoles, suggesting that the actin cytoskeleton is important in secretory vesicle transport. Disruption of microtubules with nocodazole led to hyperbranching but did not cause intracellular accumulation, suggesting that microtubules play a role in directing vesicle transport rather than vesicle movement per se. Treatment of regenerating protoplasts confirmed that BFA and cytochalasin but not nocodazole inhibited protein secretion. When germlings were subjected to carbon starvation, vacuolation was rapidly initiated throughout the hyphae and GFP fluorescence was visible in some of the vacuoles, indicating retargeting of the fusion protein from the secretory pathway to the vacuoles. PMID:11277626

Khalaj, V; Brookman, J L; Robson, G D

2001-02-01

376

Production of phytase (myo-inositolhexakisphosphate phosphohydrolase) by Aspergillus niger van Teighem in laboratory-scale fermenter.  

PubMed

The growth and production pattern of phytase by a filamentous fungus, Aspergillus niger van Teighem, were studied in submerged culture at varying agitation rates and controlled and uncontrolled pH conditions. Allowing the initial culture to grow under neutral condition with subsequent decline in pH resulted in increased phytase productivity. A maximum of 141 nkat/mL phytase was obtained when the broth pH was maintained at pH 2.5 as compared to 17 nkat/mL units at controlled pH 5.5. The culture morphology and rheological properties of the fermentation broth significantly varied with the agitation rate. The volumetric oxygen transfer coefficient was determined at different phases of fungal growth during batch fermentation using static gassing out and dynamic gassing out methods. The oxygen transfer coefficient (k(L)a) of the fermenter was found to be 125 h(-)(1) at 500 rpm as compared to 38 h(-)(1) at 200 rpm. The oxygen transfer rates at different phases of growth were significantly affected by cell mass concentration and fungal morphology. During the course of fermentation there was a gradual decline of k(L)a from 97 h(-)(1) on day 2 to 63 h(-)(1) on day 6 of fermentation, after which no significant change was observed. The degree of agitation considerably influenced the culture morphology where shear thinning of filamentous fungus was observed with the increase in agitation. PMID:15176876

Vats, Purva; Sahoo, D K; Banerjee, U C

2004-01-01

377

Scale up of a novel tri-substrate fermentation for enhanced production of Aspergillus niger lipase for tallow hydrolysis.  

PubMed

A novel tri-substrate fermentation (TSF) process was developed for the production of lipase from Aspergillus niger MTCC 2594 using agro-industrial residues, wheat bran (WB), coconut oil cake (COC) and an agro-product, wheat rawa (WR). The lipase activity was 628.7+/-13 U/g dry substrate (U/gds) at 30 degrees C and 96 h and growth studies indicated that addition of WR significantly augmented the biomass and lipase production. Scale up of lipase production at 100g and 3 kg (3 x 1 kg) tray-level batch fermentation resulted in 96% and 83.0% of enzyme activities, respectively, at 72 h. Maximum activity of 745.7+/-11U/gds was obtained, when fermented substrate was extracted in buffer containing 1% (w/v) sodium chloride and 0.5% (w/v) Triton X-100. Furthermore, the direct application of fermented substrate for tallow hydrolysis makes the process economical for industrial production of biofuel. PMID:20400303

Edwinoliver, N G; Thirunavukarasu, K; Naidu, R B; Gowthaman, M K; Kambe, T Nakajima; Kamini, N R

2010-09-01

378

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

379

Production of high concentrations of ethanol from inulin by simultaneous saccharification and fermentation using Aspergillus niger and Saccharomyces cerevisiae.  

PubMed

Pure nonhydrolyzed inulin was directly converted to ethanol in a simultaneous saccharification and fermentation process. An inulinase-hyperproducing mutant, Aspergillus niger 817, was grown in a submerged culture at 30 degrees C for 5 days. The inulin-digestive liquid culture (150 ml) was supplemented with 45 g of inulin, 0.45 g of (NH4)2SO4, and 0.15 g of KH2PO4. The medium (pH 5.0) was inoculated with an ethanol-tolerant strain, Saccharomyces cerevisiae 1200, and fermentation was conducted at 30 degrees C. An additional 20 g of inulin was added to the culture after 15 h of fermentation. S. cerevisiae 1200 utilized 99% of the 65 g of inulin during the fermentation, and produced 20.4 and 21.0% (vol/vol) ethanol from chicory and dahlia inulins, respectively, within 3 days of fermentation. The maximum volumetric productivities of ethanol were 6.2 and 6.0 g/liter/h for chicory and dahlia inulins, respectively. The conversion efficiency of inulin to ethanol was 83 to 84% of the theoretical ethanol yield. PMID:8481000

Ohta, K; Hamada, S; Nakamura, T

1993-03-01

380

Cloning, purification, and characterization of a heat- and alkaline-stable endoglucanase B from Aspergillus niger BCRC31494.  

PubMed

Endoglucanase B (EGLB) derived from Aspergillus niger BCRC31494 has been used in the food fermentation industry because of its thermal and alkaline tolerance. It was cloned and expressed in Pichia pastoris. According to sequence analysis, the gene open reading frame comprises 1,217 bp with five introns (GenBank GQ292753). According to sequence and protein domain analyses, EGLB was assigned to glycosyl hydrolase family 5 of the cellulase superfamily. Several binding sites were found in the promoter region. The purified recombinant enzyme was induced by 0.5% methanol, and it exhibited optimal activity at 70 °C and pH 4. EGLB was stable for 3 h at temperatures below 60 °C, with more than 90% of its activity remaining. The enzyme was specific for substrates with ?-1,3 and ?-1,4 linkages. In Lineweaver-Burk plot analysis, the K(m) and V(max) values of EGLB for ?-D-glucan were 134 mg/mL and 4.68 U/min/mg, respectively. The enzyme activity was increased by 1.86-fold by Co˛? and by 2-fold by Triton X-100 and Tween 80. These favorable properties make EGLB a potential candidate for use in laundry and textile industrial applications. PMID:22893022

Li, Chien-Huang; Wang, Hsing-Ren; Yan, Tsong-Rong

2012-01-01

381

Optimization of date syrup for enhancement of the production of citric acid using immobilized cells of Aspergillus niger.  

PubMed

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. PMID:23961184

Mostafa, Yasser S; Alamri, Saad A

2012-04-01

382

Characterization of ? -Glucosidase Produced by Aspergillus niger under Solid-State Fermentation and Partially Purified Using MANAE-Agarose.  

PubMed

? -Glucosidase (BGL) is a hydrolytic enzyme with specificity for a wide variety of glycoside substrates, being an enzyme with a large range of biotechnological applications. However, enzyme properties can be different depending both on the microorganism and the cultivation procedure employed. Therefore, in order to explore potential biocatalytical applications of novel enzymes, their characterization is essential. In this work, a BGL synthesized by a selected strain of Aspergillus niger cultivated under solid-state fermentation (SSF) was partially purified and fully characterized in terms of optimum pH, temperature, and thermostability. The single-step purification using MANAE-agarose in a chromatographic column yielded an enzyme solution with specific activity (17.1?IU/mg protein) adequate for the characterization procedures. Electrophoresis SDS-PAGE and size-exclusion chromatography analysis resulted in an estimated molecular mass of 60?kDa. Higher enzyme activities were found in the range between 40 and 65°C and between pH 4 and 5.5, indicating an interesting characteristic for application in the hydrolysis of lignocellulosic biomass for biofuels production. Thermostability studies of purified BGL resulted in half-lives at 37°C of 56.3?h and at 50°C of 5.4?h. These results provide support for further studies of this enzyme towards revealing its potential biotechnological applications. PMID:24940510

Baraldo Junior, Anderson; Borges, Diogo G; Tardioli, Paulo W; Farinas, Cristiane S

2014-01-01

383

[Optimization of culture conditions of Aspergillus niger for the synthesis of alpha-N-acetylgalactosaminidase and alpha-galactosidase].  

PubMed

Different factors have been investigated for their effect on the process of biosynthesis of alpha-N-acetylgalactosaminidase and alpha-galactosidase of Aspergillus niger under deep-water cultivation. Optimal sources and concentrations of carbon (soy flour--25 g/l) and nitrogen (pepton--7.5 g/l) were estimated. It has been established that temperature of 25 degrees C, pH 6.0, growing in 50 ml medium at the swing velocity 220 rev/min. for 6-8 days are optimal cultivation parameters. It has been shown that dry borine blood (in concentration of 1%) and a number of guanidine derivatives (guanidine carbonate--0.25%, nitroaminoguanison dimethylaminobenzaldehyde--0.05%, nitroaminoguanison of salicylic aldehyde--0.1%) can play the part of inducers of the mentioned glycosidase synthesis. When growing fungal culture in selected conditions synthesis of enzymes increased almost 3 times. Activity of alpha-N-acetylgalactosaminidase was 0.46 E/ml, and alpha-galactosidase--1.9 E/ml. PMID:11692674

Borzova, N V; Malanchuk, V M; Varbanets, L D; Se?fullina, I I; Zubkov, S V

2001-01-01

384

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 2ł. Residual activities of 145.1 and 148.5% were observed for LPG (30 bar, 6 h, and depressurization rate of 20 bar?min?ą) and propane (270 bar, 1 h, and depressurization rate of 100 bar?min?ą), 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

2013-02-01

385

Characterization of ?-Glucosidase Produced by Aspergillus niger under Solid-State Fermentation and Partially Purified Using MANAE-Agarose  

PubMed Central

?-Glucosidase (BGL) is a hydrolytic enzyme with specificity for a wide variety of glycoside substrates, being an enzyme with a large range of biotechnological applications. However, enzyme properties can be different depending both on the microorganism and the cultivation procedure employed. Therefore, in order to explore potential biocatalytical applications of novel enzymes, their characterization is essential. In this work, a BGL synthesized by a selected strain of Aspergillus niger cultivated under solid-state fermentation (SSF) was partially purified and fully characterized in terms of optimum pH, temperature, and thermostability. The single-step purification using MANAE-agarose in a chromatographic column yielded an enzyme solution with specific activity (17.1?IU/mg protein) adequate for the characterization procedures. Electrophoresis SDS-PAGE and size-exclusion chromatography analysis resulted in an estimated molecular mass of 60?kDa. Higher enzyme activities were found in the range between 40 and 65°C and between pH 4 and 5.5, indicating an interesting characteristic for application in the hydrolysis of lignocellulosic biomass for biofuels production. Thermostability studies of purified BGL resulted in half-lives at 37°C of 56.3?h and at 50°C of 5.4?h. These results provide support for further studies of this enzyme towards revealing its potential biotechnological applications.

Borges, Diogo G.; Tardioli, Paulo W.; Farinas, Cristiane S.

2014-01-01

386

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

387

Characterization and constitutive expression of a novel endo-1,4-?-D-xylanohydrolase from Aspergillus niger in Pichia pastoris.  

PubMed

A putative endo-1,4-?-D-xylanohydrolase gene xyl10 from Aspergillus niger, encoding a 308-residue mature xylanase belonging to glycosyl hydrolase family 10, was constitutively expressed in Pichia pastoris. The recombinant Xyl10 exhibited optimal activity at pH 5.0 and 60 °C with more than 50 % of the maximum activity from 40 to 70 °C. It retained more than 90 % of the original activity after incubation at 60 °C (pH 5.0) for 30 min and more than 74 % after incubation at pH 3.0-13.0 for 2 h (25 °C). The specific activity, K m and V max values for purified Xyl10 were, respectively, 3.2 × 10(3) U mg(-1), 3.6 mg ml(-1) and 5.4 × 10(3) ?mol min(-1 )mg(-1) towards beechwood xylan. The enzyme degraded xylan to a series of xylooligosaccharides and xylose. The recombinant enzyme with these properties has the potential for various industrial applications. PMID:23690032

Zheng, Jia; Guo, Ning; Wu, Lishuang; Tian, Jian; Zhou, Hongbo

2013-09-01

388

Optimization of nutrient medium containing agricultural wastes for xylanase production by Aspergillus niger B03 using optimal composite experimental design.  

PubMed

The xylanase biosynthesis is induced by its substrate - xylan. The high xylan content in some of the wastes like corn cobs and wheat bran makes them an accessible and cheap source of inducers. Nutrient medium for xylanase biosynthesis in submerged cultivation of Aspergillus niger B03 has been optimized. The optimization process was analyzed using optimal composite experimental design and response surface methodology. The predicted by the regression model optimum components of nutrient medium are as follows (g/l): (NH(4))(2)HPO(4) 2.6, urea 0.9, corn cobs 24.0, wheat bran 14.6 and malt sprout 6.0. Five parallel experiments have been carried out, at definite, optimum components concentrations of the nutrient medium, and a mean value of the activity Y=996.30 U/ml has been obtained. The xylanase activity, obtained with the optimized nutrient medium is 33% higher than the activity, achieved with the basic medium. PMID:17092711

Dobrev, Georgi Todorov; Pishtiyski, Ivan Genov; Stanchev, Veselin Stanchev; Mircheva, Rositza

2007-10-01

389

Semi-solid-state fermentation of Eicchornia crassipes biomass as lignocellulosic biopolymer for cellulase and 3-glucosidase production by cocultivation of Aspergillus niger RK3 and Trichoderma reesei MTCC164.  

PubMed

An aquatic weed biomass, Eicchornia crassipes, present in abundance and leading to a threatening level of water pollution was used as substrate for cellulase and beta-glucosidase production using wild-type strain Aspergillus niger RK3 that was isolated from decomposing substrate. Alkali treatment of the biomass (10%) resulted in a 60-66% increase in endoglucanase, exoglucanase, and beta-glucosidase production by the A. niger RK3 strain in semi-solid-state fermentation. Similarly, the alkali-treated biomass led to a 45-54% increase in endo- and exoglucanase and a higher (98%) increase in beta-glucosidase production by Trichoderma reesei MTCC164 under similar conditions. However, the cocultivation of A. niger RK3 and T. reesei MTCC164 at a ratio of 3:1 showed a 20-24% increase in endo- and exoglucanase activities and about a 13% increase in the beta-glucosidase activity over the maximum enzymatic activities observed under single culture conditions. Multistep physical (ultraviolet) and chemical (N-methyl-N'-nitrosoguanidine, sodium azide, colchicine) mutagenesis of the A. niger RK3 strain resulted in a highly cellulolytic mutant, UNSC-442, having an increase of 136, 138, and 96% in endoglucanase, exoglucanase, and beta-glucosidase, activity, respectively. The cocultivation of mutant UNSC-442 along with T. reesei MTCC164 (at a ratio of 3:1) showed a further 10-11% increase in endo- and exoglucanase activities and a 29% increase in beta-glucosidase activity in semi-solid-state fermentation. PMID:11783902

Kumar, R; Singh, R P

2001-01-01

390

Kinetic characterization of glucose aerodehydrogenase from Aspergillus niger EMS-150-F after optimizing the dose of mutagen for enhanced production of enzyme.  

PubMed

In the present study enhanced production of glucose aerodehydrogenase from Aspergillus niger has been achieved after optimizing the dose of chemical mutagen ethyl methane sulfonate (EMS) that has not been reported earlier. Different doses of mutagen were applied and a strain was developed basing upon the best production. The selected strain Aspergillus niger EMS-150-F was optimized for nutrient requirements in order to produce enzyme through fermentation and the results showed the best yield at 2% corn steep liquor (CSL), 36 hours fermentation time, pH 5, 30°C temperature, 0.3% KH2PO4, 0.3% urea and 0.06% CaCO3. The enzyme was then purified and resulted in 57.88 fold purification with 52.12% recovery. On kinetic characterization, the enzyme showed optimum activity at pH 6 and temperature 30°C. The Michaelis-Menton constants (Km, Vmax, Kcat and Kcat/Km) were 20 mM, 45.87 U mL(-1), 1118.81 s(-1) and 55.94 s(-1) mM(-1), respectively. The enzyme was found to be thermaly stable and the enthalpy and free energy showed an increase with increase in temperature and ?S* was highly negative proving the enzyme from A. niger EMS-150-F resistant to temperature and showing a very little disorderliness. PMID:24688499

Umbreen, Huma; Zia, Muhammad Anjum; Rasul, Samreen

2013-12-01

391

Kinetic characterization of glucose aerodehydrogenase from Aspergillus niger EMS-150-F after optimizing the dose of mutagen for enhanced production of enzyme  

PubMed Central

In the present study enhanced production of glucose aerodehydrogenase from Aspergillus niger has been achieved after optimizing the dose of chemical mutagen ethyl methane sulfonate (EMS) that has not been reported earlier. Different doses of mutagen were applied and a strain was developed basing upon the best production. The selected strain Aspergillus niger EMS-150-F was optimized for nutrient requirements in order to produce enzyme through fermentation and the results showed the best yield at 2% corn steep liquor (CSL), 36 hours fermentation time, pH 5, 30°C temperature, 0.3% KH2PO4, 0.3% urea and 0.06% CaCO3. The enzyme was then purified and resulted in 57.88 fold purification with 52.12% recovery. On kinetic characterization, the enzyme showed optimum activity at pH 6 and temperature 30°C. The Michaelis-Menton constants (Km, Vmax, Kcat and Kcat/Km) were 20 mM, 45.87 U mL?1, 1118.81 s?1 and 55.94 s?1 mM?1, respectively. The enzyme was found to be thermaly stable and the enthalpy and free energy showed an increase with increase in temperature and ?S* was highly negative proving the enzyme from A. niger EMS-150-F resistant to temperature and showing a very little disorderliness.

Umbreen, Huma; Zia, Muhammad Anjum; Rasul, Samreen

2013-01-01

392

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

393

Leporizines A-C: epithiodiketopiperazines isolated from an Aspergillus species.  

PubMed

Three new compounds named leporizines A-C 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

2013-09-27

394

Trehalose synthesis in Aspergillus niger: characterization of six homologous genes, all with conserved orthologs in related species  

PubMed Central

Background The disaccharide trehalose is a major component of fungal spores and is released upon germination. Moreover, the sugar is well known for is protective functions, e.g. against thermal stress and dehydration. The properties and synthesis of trehalose have been well investigated in the bakers’ yeast Saccharomyces cerevisiae. In filamentous fungi, such knowledge is limited, although several gene products have been identified. Results Using Aspergillus niger as a model fungus, the aim of this study was to provide an overview of all genes involved in trehalose synthesis. This fungus has three potential trehalose-6-phosphate synthase encoding genes, tpsA-C, and three putative trehalose phosphate phosphatase encoding genes, tppA-C, of which two have not previously been identified. Expression of all six genes was confirmed using real-time PCR, and conserved orthologs could be identified in related Aspergilli. Using a two-hybrid approach, there is a strong indication that four of the proteins physically interact, as has previously been shown in S. cerevisiae. When creating null mutants of all the six genes, three of them, ?tpsA, ?tppA and ?tppB, had lower internal trehalose contents. The only mutant with a pronounced morphological difference was ?tppA, in which sporulation was severely reduced with abnormal conidiophores. This was also the only mutant with accumulated levels of trehalose-6-phosphate, indicating that the encoded protein is the main phosphatase under normal conditions. Besides ?tppA, the most studied deletion mutant in this work was ?tppB. This gene encodes a protein conserved in filamentous Ascomycota. The ?tppB mutant displayed a low, but not depleted, internal trehalose content, and conidia were more susceptible to thermal stress. Conclusion A. niger contains at least 6 genes putatively involved in trehalose synthesis. Gene expressions related to germination have been quantified and deletion mutants characterized: Mutants lacking tpsA, tppA or tppB have reduced internal trehalose contents. Furthermore, tppA, under normal conditions, encodes the functional trehalose-6-phosphate-phosphatase.

2014-01-01

395

Effect of low shear modeled microgravity on phenotypic and central chitin metabolism in the filamentous fungi Aspergillus niger and Penicillium chrysogenum.  

PubMed

Phenotypic and genotypic changes in Aspergillus niger and Penicillium chrysogenum, spore forming filamentous fungi, with respect to central chitin metabolism were studied under low shear modeled microgravity, normal gravity and static conditions. Low shear modeled microgravity (LSMMG) response showed a similar spore germination rate with normal gravity and static conditions. Interestingly, high ratio of multiple germ tube formation of A. niger in LSMMG condition was observed. Confocal laser scanning microscopy images of calcofluor flurophore stained A. niger and P. chrysogenum showed no significant variations between different conditions tested. Transmission electron microscopy images revealed number of mitochondria increased in P. chrysogenum in low shear modeled microgravity condition but no stress related-woronin bodies in fungal hyphae were observed. To gain additional insight into the cell wall integrity under different conditions, transcription level of a key gene involved in cell wall integrity gfaA, encoding the glutamine: fructose-6-phosphate amidotransferase enzyme, was evaluated using qRT-PCR. The transcription level showed no variation among different conditions. Overall, the results collectively indicate that the LSMMG has shown no significant stress on spore germination, mycelial growth, cell wall integrity of potentially pathogenic fungi, A. niger and P. chrysogenum. PMID:24803238

Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo

2014-08-01

396

Mapping N-linked Glycosylation Sites in the Secretome and Whole Cells of Aspergillus niger Using Hydrazide Chemistry and Mass Spectrometry  

SciTech Connect

Protein glycosylation is known to play an essential role in both cellular functions and the secretory pathways; however, little information is available on the dynamics of glycosylated N-linked glycosites of fungi. Herein we present the first extensive mapping of glycosylated N-linked glycosites in industrial strain Aspergillus niger by applying an optimized solid phase enrichment of glycopeptide protocol using hydrazide modified magnetic beads. The enrichment protocol was initially optimized using mouse plasma and A. niger secretome samples, which was then applied to profile N-linked glycosites from both the secretome and whole cell lysates of A. niger. A total of 847 unique N-linked glycosites and 330 N-linked glycoproteins were confidently identified by LC-MS/MS. Based on gene ontology analysis, the identified N-linked glycoproteins in the whole cell lysate were primarily localized in the plasma membrane, endoplasmic reticulum, golgi apparatus, lysosome, and storage vacuoles. The identified N-linked glycoproteins are involved in a wide range of biological processes including gene regulation and signal transduction, protein folding and assembly, protein modification and carbohydrate metabolism. The extensive coverage of glycosylated N-linked glycosites along with identification of partial N-linked glycosylation in those enzymes involving in different biochemical pathways provide useful information for functional studies of N-linked glycosylation and their biotechnological applications in A. niger.

Wang, Lu; Aryal, Uma K.; Dai, Ziyu; Mason, Alisa C.; Monroe, Matthew E.; Tian, Zhixin; Zhou, Jianying; Su, Dian; Weitz, Karl K.; Liu, Tao; Camp, David G.; Smith, Richard D.; Baker, Scott E.; Qian, Weijun

2012-01-01

397

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

2012-01-01

398

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

399

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

400

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

401

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

402

Submerged Conidiation and Product Formation by Aspergillus niger at Low Specific Growth Rates Are Affected in Aerial Developmental Mutants ?  

PubMed Central

Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (?fwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B2, B4, and B6 were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ?fwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance.

J?rgensen, Thomas R.; Nielsen, Kristian F.; Arentshorst, Mark; Park, JooHae; van den Hondel, Cees A.; Frisvad, Jens C.; Ram, Arthur F.

2011-01-01

403

Submerged conidiation and product formation by Aspergillus niger at low specific growth rates are affected in aerial developmental mutants.  

PubMed

Exposure to an aerial environment or severe nutrient limitation induces asexual differentiation in filamentous fungi. Submerged cultivation of Aspergillus niger in carbon- and energy-limited retentostat cultures both induces and fuels conidiation. Physiological and transcriptomic analyses have revealed that this differentiation strongly affects product formation. Since conidiation is inherent in the aerial environment, we hypothesized that product formation near zero growth can be influenced by affecting differentiation or development of aerial hyphae in general. To investigate this idea, three developmental mutants (?fwnA, scl-1, and scl-2 mutants) that have no apparent vegetative growth defects were cultured in maltose-limited retentostat cultures. The secondary-metabolite profile of the wild-type strain defined flavasperone, aurasperone B, tensidol B, and two so far uncharacterized compounds as associated with conidium formation, while fumonisins B(2), B(4), and B(6) were characteristic of early response to nutrient limitation by the vegetative mycelium. The developmental mutants responded differently to the severe substrate limitation, which resulted in distinct profiles of growth and product formation. fwnA encodes the polyketide synthase responsible for melanin biosynthesis during aerial differentiation, and we show that conidial melanin synthesis in submerged retentostat cultures and aurasperone B production are fwnA dependent. The scl-1 and scl-2 strains are two UV mutants generated in the ?fwnA background that displayed reduced asexual conidiation and formed sclerotium-like structures on agar plates. The reduced conidiation phenotypes of the scl-1 and scl-2 strains are reflected in the retentostat cultivation and are accompanied by elimination or severely reduced accumulation of secondary metabolites and distinctly enhanced accumulation of extracellular protein. This investigation shows that submerged conidiation and product formation of a mitosporic fungus cultured at low specific growth rates can be fundamentally affected by interfering with the genetic program for differentiation of aerial hyphae, opening new perspectives for tailoring industrial performance. PMID:21652743

Jřrgensen, Thomas R; Nielsen, Kristian F; Arentshorst, Mark; Park, Joohae; van den Hondel, Cees A; Frisvad, Jens C; Ram, Arthur F

2011-08-01

404

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

405

In vitro antifungal activity of farnesyltransferase inhibitors against clinical isolates of Aspergillus and Candida  

PubMed Central

Background Protein farnesylation is an important tosttranslational modification in fungi. We evaluated the antifungal activity of two farnesyltransferase inhibitors against clinical isolates of Aspergillus and Candida. Methods Disk diffusion assay and broth microdilution assay were used to determine the antifungal susceptibility of two farnesyltransferase inhibitors (manumycin A and tipifarnib) against clinical isolates of Aspergillus and Candida. Results Disk diffusion assay demonstrated both agents had activity against Aspergillus and Candida. The minimal inhibitory concentration (MIC) ranges for manumycin A against Aspergillus and Candida were 200 to 400 ?M and 13 to >25 ?M, respectively. Unfortunately, the MIC were vastly higher than the concentrations that inhibit the proliferation and viability of mammalian cells. The MICs of tipifarnib against Aspergillus and Candida were >1600 ?M. Conclusion The outcome of present study showed that farnesyltransferase inhibitors have activity against Aspergillus and Candida. This suggests that farnesyltransferase may be used as anifungal target in designing and developing new drugs.

2013-01-01

406

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

407

Role of ozone in UV-C disinfection, demonstrated by comparison between wild-type and mutant conidia of Aspergillus niger.  

PubMed

This study aimed to investigate the tolerance of a melanized wild-type strain of Aspergillus niger (CON1) and its light-colored mutant (MUT1) to UV-C light and the concomitantly generated ozone. Treatments were segregated into four groups based on whether UV irradiation was used and the presence or absence of ozone: (-UV, -O3), (-UV, +O3), (+UV, -O3) and (+UV, +O3). The survival of CON1 and MUT1 conidia under +UV decreased as the exposure time increased, with CON1 showing greater resistance to UV irradiation than MUT1. Ozone induced CON1 conidium inactivation only under conditions of UV radiation exposure. While, the inactivation effect of ozone on MUT1 was always detectable regardless of the presence of UV irradiation. Furthermore, the CON1 conidial suspension showed lower UV light transmission than MUT1 when examined at the same concentration. Compared with the pigment in MUT1, the melanin in CON1 exhibited more potent radical-scavenging activity and stronger UV absorbance. These results suggested that melanin protected A. niger against UV disinfection via UV screening and free radical scavenging. The process by which UV-C disinfection induces a continual decrease in conidial survival suggests that UV irradiation and ozone exert a synergistic fungicidal effect on A. niger prior to reaching a plateau. PMID:24283963

Liu, Jing; Zhou, Lin; Chen, Ji-Hong; Mao, Wang; Li, Wen-Jian; Hu, Wei; Wang, Shu-Yang; Wang, Chun-Ming

2014-01-01

408

Computerized study of interactions among factors and their optimization through response surface methodology for the production of tannin acyl hydrolase by Aspergillus niger PKL 104 under solid state fermentation  

Microsoft Academic Search

Optimization of five parameters (initial moisture, initial pH, incubation temperature, inoculum ratio and fermentation period), as per central composite rotable design falling under the response surface methodology, was attempted in a total of 32 experimental sets, after fitting the experimental data to the polynomial model of a suitable degree, for tannin acyl hydrolase production by Aspergillus niger PKL 104 in

P. K. Lekha; Nagin Chand; B. K. Lonsane

1994-01-01

409

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