李文清; 何鸣; 罗进贤
Aspergillus niger glucoamylase GA 1 cDNA was inserted in between the yeast PGK promoter and terminator on plasmid pMA91. The resultant plasmid pMAG69 was introduced into Saccharomyces cerevisiae GRF18 by protoplast transformation. The A niger GA I cDNA was expressed efficiently under the contiol of PGK promoter and 99% of the gene products were secreted into the culture medium using its own signal sequence The recombmant yeast can digest 87% of starch in 2 d in the medium containing 10% starch. The recombinant plasmid pMAG69 can exist stably in 5. cerevisiae.
Cornett, Catherine A G; Fang, Tsuei-Yun; Reilly, Peter J; Ford, Clark
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.
Li, Lianwei; Lu, Hongzhong; Xia, Jianye; Chu, Ju; Zhuang, Yingping; Zhang, Siliang
Carbon-limited continuous culture was used to study the relationship between the growth of Aspergillus niger and the production of glucoamylase. The result showed that when the specific growth rate was lower than 0.068 h(-1), the production of glucoamylase was growth-associated, when the specific growth rate was higher than 0.068 h(-1), the production of glucoamylase was not growth-associated. Based on the result of continuous culture, the Monod dynamics model of glucose consumption of A. niger was constructed, Combining Herbert-Pirt equation of glucose and oxygen consumption with Luedeking-Piret equation of enzyme production, the black-box model of Aspergillus niger for enzyme production was established. The exponential fed-batch culture was designed to control the specific growth rate at 0.05 h(-1) by using this model and the highest yield for glucoamylase production by A. niger reached 0.127 g glucoamylase/g glucose. The black-box model constructed in this study successfully described the glucoamylase production by A. niger and the result of the model fitted the measured value well. The black-box model could guide the design and optimization of glucoamylase production by A. niger.
Swift, R.J.; Karandikar, A.; Griffen, A.M.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Robson, G.D.; Trinci, A.P.J.; Wiebe, M.G.
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, casa
Pedersen, Henrik; Beyer, Michael; Nielsen, Jens
The Aspergillus niger strain BO-1 was grown in batch, continuous (chemostat) and fed-batch cultivations in order to study the production of the extracellular enzyme glucoamylase under different growth conditions. In the pH range 2.5-6.0, the specific glucoamylase productivity and the specific...
An extracellular glucoamylase enzyme was isolated from Aspergillus niger Z10 natural isolate in a liquid Czapek Dox medium which contained soluble starch (2%) as the sole carbon source. The molecular weight of the enzyme was found to be about 100.000 Daltons through Starch-SDS Polyacrylamide Gel Electrophoresis. The optimal pH range of the enzyme was found to be 4.5-5.5 and it was determined that the thermal stability of this enzyme is quite high.
An extracellular glucoamylase enzyme was isolated from Aspergillus niger Z10 natural isolate in a liquid Czapek Dox medium which contained soluble starch (2%) as the sole carbon source. The molecular weight of the enzyme was found to be about 100.000 Daltons through Starch-SDS Polyacrylamide Gel Electrophoresis. The optimal pH range of the enzyme was found to be 4.5-5.5 and it was determined that the thermal stability of this enzyme is quite high.
Morris, V. M.; Gunning, A. P.; Faults, C. B.
Atomic force microscopy has been used to investigate the complexes formed between high molecular weight amylose chains and Aspergillus niger glucoamylase mutants (E400Q and W52F), wild-type A. niger starch binding domains (SBDS), and mutant SBDs (W563K and W590K) lacking either of the two starch ...
Smith, T.L. (Dept. of Agriculture, Madison, WI (United States) Univ. of Wisconsin, Madison (United States)); Gaskell, J.; Cullen, D. (Dept. of Agriculture, Madison, WI (United States)); Berka, R.M.; Yang, M.; Henner, D.J. (Genentech Inc., San Francisco, CA (United States))
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 (Hy[sup R]) Ustilago maydis transformants. This is an example of an Ascomycete promoter functioning in a Basidiomycete. Hy[sup R] 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 transcription start points are the same in U. maydis and A. niger.
Kwon Min Jin
Full Text Available Abstract Background Filamentous fungi such as Aspergillus niger are well known for their exceptionally high capacity for secretion of proteins, organic acids, and secondary metabolites and they are therefore used in biotechnology as versatile microbial production platforms. However, system-wide insights into their metabolic and secretory capacities are sparse and rational strain improvement approaches are therefore limited. In order to gain a genome-wide view on the transcriptional regulation of the protein secretory pathway of A. niger, we investigated the transcriptome of A. niger when it was forced to overexpression the glaA gene (encoding glucoamylase, GlaA and secrete GlaA to high level. Results An A. niger wild-type strain and a GlaA over-expressing strain, containing multiple copies of the glaA gene, were cultivated under maltose-limited chemostat conditions (specific growth rate 0.1 h-1. Elevated glaA mRNA and extracellular GlaA levels in the over-expressing strain were accompanied by elevated transcript levels from 772 genes and lowered transcript levels from 815 genes when compared to the wild-type strain. Using GO term enrichment analysis, four higher-order categories were identified in the up-regulated gene set: i endoplasmic reticulum (ER membrane translocation, ii protein glycosylation, iii vesicle transport, and iv ion homeostasis. Among these, about 130 genes had predicted functions for the passage of proteins through the ER and those genes included target genes of the HacA transcription factor that mediates the unfolded protein response (UPR, e.g. bipA, clxA, prpA, tigA and pdiA. In order to identify those genes that are important for high-level secretion of proteins by A. niger, we compared the transcriptome of the GlaA overexpression strain of A. niger with six other relevant transcriptomes of A. niger. Overall, 40 genes were found to have either elevated (from 36 genes or lowered (from 4 genes transcript levels under all
［1］Qiao, D., Tang, G., Zhong, L. et al., The overall analysis and comparison of the expression of glucoamylase in the over-production strain A. niger T21 and its original strain A. niger 3.795, Acta Microbiologica Sinica (in Chinese), 1997, 37(5): 349.［2］Zhong, L, Qiao, D, Tang, G. et al., Cloning, sequencing and comparison of the 5′-flanking regions of glaA gene from high and low glucoamylase producing strains of Aspergillus niger, Acta Microbiologica Sinica (in Chinese), 1996, 36: 181.［3］Qiao, D., Zhong, L., Tang, G. et al., Cloning and sequencing of glucoamylase gene from Aspergillus niger 3.795, Chinese J. Biochem. and Mol. Biology (in Chinese), 1998, 14: 254.［4］Zhong, L., Fan, X., Tang, G., Cotransformation of glucoamylase overproducing strain Aspergillus niger T21 with niaD and uidA gene, Mycosystema (in Chinese), 1999, 18: 172.［5］Roberts, I. N., Oliver, R. P., Punt, P. J. et al., Expression of the Escherichia coli b-glucuronidase gene in industrial and phytopathogenic filamentous fungi, Curr. Genet., 1989, 15: 177.［6］Lowry, O. H., Rosebrough, N. J., Farr, A. L. et al., Protein measurement with the folin phenol reagent, J. Biochem., 1951, 193: 268.［7］Zhu, H., Qu, F., Zhu, L., Isolation of genomic DNAs from fungi using benzyl chloride, Acta Mycologica Sinica (in Chi-nese), 1994, 13: 34.［8］Verwoerd, T. C., Dekker, B. M. M., Hoekema, A., A small-scale procedure for the rapid isolation of plant RNAs, Nucleic Acids Research, 1989, 17: 2362.［9］Campbell, E. I., Unkles, S. E., Marco, J. A. et al., Improved transformation efficiency of Aspergillus niger using the ho-mologous niaD gene for nitrate reductase, Curr. Genet., 1989, 16: 53.［10］Fowler, T., Berka, R. M., Ward, M., Regulation of the glaA gene of Aspergillus niger, Curr. Genet., 1990, 18: 537.［11］Verdoes, J. C., Punt, P. J., Stouthamer, A. H. et al., The effect of multiple copies of the upstream region on expression of the Aspergillus niger glucoamylase
Christiane Trevisan Slivinski
Full Text Available In this work, glucoamylase was produced by Aspergillus niger in solid-state fermentation. The enzyme was partially purified by ammonium sulphate precipitation and ion exchange and gel filtration chromatographies. Its molecular mass was estimated as 118.17 kDa by electrophoresis. The partially purified enzyme had an optimum pH range of 4.5-5.0 and an optimum temperature of 60 °C, with average activity 152.85 U mL-1. Thermal and pH stability assays with the crude extract showed that more than 60 % of the activity remained at pH 4.6 and 60 °C, even after an exposition to these conditions longer than 24 h. Yet, after purification, the enzyme was stable at these for at least 4 h, which indicated that its purification for use in starch saccharification was inadvisable. K M and Vmax were 0.34 mg mL-1 and 160.22 U mL-1, respectively.
Jørgensen, Anders Dysted; Nøhr, Jane; Kastrup, Jette Sandholm
The industrially important glucoamylase 1 is an exo-acting glycosidase with substrate preference for alpha-1,4 and alpha-1,6 linkages at non-reducing ends of starch. It consists of a starch binding and a catalytic domain interspersed by a highly glycosylated polypeptide linker. The linker function...... is poorly understood and structurally undescribed, and data regarding domain organization and intramolecular functional cooperativity are conflicting or non-comprehensive. Here, we report a combined small angle x-ray scattering and calorimetry study of Aspergillus niger glucoamylase 1, glucoamylase 2, which...
The molecular basis for increasing of the glucoamylase (GLA) production of an Aspergillus niger mutant T21 was investigated . Northern blot analysis showed that the amount of glaA specific mRNA of A . niger T21 was about 20 times higher than that of its start strain A . niger AS 3.795. The two glaA promoter fusions (PglaA)-uidAs were respectively introduced into A . niger. Analysis of GUS activity of the transformants revealed that the PglaA activity of the strain T21 is about 3 times stronger than that of the strain AS 3.795. It is considered to be one of the reasons for the increase of glaA transcriptional level in the strain T21. However, comparing with the 20 times increase in the amount of glaA mRNA the alteration of trans regulation should be the most important reason for that. The results of deletion analysis of 5′-cis region of A . niger T21 glaA gene indicated that the region from - 408 to - 513 bp upstream of ATG is responsible for the high level expression of glaA.
Kwon, M.J.; Jorgensen, T.R.; Nitsche, B.M.; Arentshorst, M.; Park, J.; Ram, A.F.J.; Meyer, V.
Background: Filamentous fungi such as Aspergillus niger are well known for their exceptionally high capacity for secretion of proteins, organic acids, and secondary metabolites and they are therefore used in biotechnology as versatile microbial production platforms. However, system-wide insights int
Al-Sheikh, Hashem M.
The ability of many filamentous fungi, such as Aspergillus niger, to secret a high level of homologous proteins has led to their consideration as hosts for the production of heterologous proteins. However, the levels of some secreted heterologous proteins have often been low. Although many strategies have been developed to improve the level of secreted heterologous proteins, further studies into the remaining bottlenecks are required. One common strategy used to improve secreted protein produ...
Paldi, Tzur; Levy, Ilan; Shoseyov, Oded
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. PMID:12646045
Juge, N.; Nøhr, J.; Le Gal-Coëffet, M.-F.
High affinity for starch granules of certain amylolytic enzymes is mediated by a separate starch binding domain (SBD). In Aspergillus niger glucoamylase (GA-I), a 70 amino acid O-glycosylated peptide linker connects SBD with the catalytic domain. A gene was constructed to encode barley alpha......-amylase 1 (AMY1) fused C-terminally to this SBD via a 37 residue GA-I linker segment. AMY1-SBD was expressed in A. niger, secreted using the AMY1 signal sequence at 25 mg x L(-1) and purified in 50% yield. AMY1-SBD contained 23% carbohydrate and consisted of correctly N-terminally processed multiple forms...
Aalbæk, Thomas; Reeslev, Morten; Jensen, Bo;
In order to identify factors responsible for production of multiple forms of glucoamylase (GA) by Aspergillus niger Bo-1, the fungus was cultured in both complex and defined media in pH-controlled batch fermenters and chemostats. At all culture conditions three forms of GA were produced with mole......In order to identify factors responsible for production of multiple forms of glucoamylase (GA) by Aspergillus niger Bo-1, the fungus was cultured in both complex and defined media in pH-controlled batch fermenters and chemostats. At all culture conditions three forms of GA were produced...... with molecular weights of approx. 91 (GAI), 73 (GAII), and 59 kDa (GAIII). Data from batch fermentations with constant pH 3.0 and 5.0 showed a uniform distribution of extracellular GA forms throughout the fermentations and independent of culture growth phases. Furthermore, steady-state data from chemostat...... cultivations at constant pH 3.0 and 5.0 showed a similar distribution of extracellular GA forms and established that the nitrogen concentration of the medium (C/N ratio) did not affect the distribution of multiple forms of GA. The extracellular acid protease activity was only moderate when the fungus...
Medda, Sukumar; Saha, Badal Chandra; Ueda, Seinosuke
Glucoamylase I of black Aspergillus was purified by (NH_4)_2SO_4 precipitation, ethanol fractionation, ion exchange chromatography on DEAE-cellulose, preparative isoelectric focusing and Sephadex G-100 gel filtration. The enzyme thus purified was found to contain no α-amylase and appeared to be homogeneous in polyacrylamide gel electrophoresis. The isoelectric point of glucoamylase I was at pH 3.4. The optimum conditions for its action on boiled soluble starch were at 60℃ and pH 4.5. The enzy...
Riaz, Muhammad; Rashid, Muhammad Hamid; Sawyer, Lindsay; Akhtar, Saeed; Javed, Muhammad Rizwan; Nadeem, Habibullah; Wear, Martin
Glucoamylases (GAs) from a wild and a deoxy-d-glucose-resistant mutant of a locally isolated Aspergillus niger were purified to apparent homogeneity. The subunit molecular mass estimated by SDS-PAGE was 93 kDa for both strains, while the molecular masses determined by MALDI-TOF for wild and mutant GAs were 72.876 and 72.063 kDa, respectively. The monomeric nature of the enzymes was confirmed through activity staining. Significant improvement was observed in the kinetic properties of the mutant GA relative to the wild type enzyme. Kinetic constants of starch hydrolysis for A. niger parent and mutant GAs calculated on the basis of molecular masses determined through MALDI-TOF were as follows: kcat = 343 and 727 s(-1), Km = 0.25 and 0.16 mg mL(-1), kcat/Km (specificity constant) = 1374 and 4510 mg mL(-1) s(-1), respectively. Thermodynamic parameters for soluble starch hydrolysis also suggested that mutant GA was more efficient compared to the parent enzyme.
Towprayoon, S.; Saha, B.C.; Fujio, Yusaku; Ueda, Seinosuke
The effect of an inhibitory factor (IF) from Aspergillus niger 19 on raw starch digestion by pure glucoamylase I of black Aspergillus, pure glucoamylase of Rhizopus niveus, bacterial ..cap alpha..-amylase, fungal ..cap alpha..-amylase and various combination was investigated. The IF caused higher inhibition of raw starch hydrolysis by the combined action of glucoamylase and fungal ..cap alpha..-amylase than of hydrolysis by the individual enzymes. A protein moiety of IF might play an active part in this inhibition phenomenon. The IF was found to starch granules, preventing hydrolysis by the enzymes, and caused decreased raw starch hydrolysis yields.
Filamentous fungi are extensively used in the fermentation industry for synthesis of numerous products. One of the most important, is the fungus Aspergillus niger, used industrially for production of organic acids, and homologous as well as heterologous enzymes. This fungus has numerous of advant......Filamentous fungi are extensively used in the fermentation industry for synthesis of numerous products. One of the most important, is the fungus Aspergillus niger, used industrially for production of organic acids, and homologous as well as heterologous enzymes. This fungus has numerous...
Schmidt, A. E.; Shvetsov, A. V.; Kuklin, A. I.; Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V.
Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.
Schmidt, A. E., E-mail: firstname.lastname@example.org; Shvetsov, A. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kuklin, A. I. [Joint Institute for Nuclear Research (Russian Federation); Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)
Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.
Aspergillus niger is abundantly found in nature. It degrades dead material of plants and animals but can also be a pathogen of these organisms. Aspergillus niger is also important for mankind because it is one of the main organisms used for the industrial production of enzymes. These enzymes are rel
Kwon, Min Jin
The research described in this thesis aims to get more fundamental insights in the molecular mechanisms used by Aspergillus niger in relation to control morphology and protein secretion. Knowledge on these two aspects is highly relevant to further optimization of A.niger as a cell factory
Wang, Fengfeng; Krijgsheld, Pauline; Hulsman, Marc; de Bekker, Charissa; Müller, Wally H; Reinders, Marcel; de Vries, Ronald P; Wösten, Han A B
Colonies of Aspergillus niger are characterized by zonal heterogeneity in growth, sporulation, gene expression and secretion. For instance, the glucoamylase gene glaA is more highly expressed at the periphery of colonies when compared to the center. As a consequence, its encoded protein GlaA is mainly secreted at the outer part of the colony. Here, multiple copies of amyR were introduced in A. niger. Most transformants over-expressing this regulatory gene of amylolytic genes still displayed heterogeneous glaA expression and GlaA secretion. However, heterogeneity was abolished in transformant UU-A001.13 by expressing glaA and secreting GlaA throughout the mycelium. Sequencing the genome of UU-A001.13 revealed that transformation had been accompanied by deletion of part of the fluG gene and disrupting its 3' end by integration of a transformation vector. Inactivation of fluG in the wild-type background of A. niger also resulted in breakdown of starch under the whole colony. Asexual development of the ∆fluG strain was not affected, unlike what was previously shown in Aspergillus nidulans. Genes encoding proteins with a signal sequence for secretion, including part of the amylolytic genes, were more often downregulated in the central zone of maltose-grown ∆fluG colonies and upregulated in the intermediate part and periphery when compared to the wild-type. Together, these data indicate that FluG of A. niger is a repressor of secretion.
Vinck, Arman; Terlou, Maarten; Pestman, Wiebe R; Martens, Edwin P; Ram, Arthur F; van den Hondel, Cees A M J J; Wösten, Han A B
Mycelial fungi play a central role in element cycling in nature by degrading dead organic material such as wood. Fungal colonization of a substrate starts with the invasion of exploring hyphae. These hyphae secrete enzymes that convert the organic material into small molecules that can be taken up by the fungus to serve as nutrients. Using green fluorescent protein (GFP) as a reporter, we show for the first time that exploring hyphae of Aspergillus niger differentiate with respect to enzyme secretion; some strongly express the glucoamylase gene glaA, while others hardly express it at all. When a cytoplasmic GFP was used, 27% of the exploring hyphae of a 5-day-old colony belonged to the low expressing hyphae. By fusing GFP to glucoamylase and by introducing an ER retention signal, this number increased to 50%. This difference is due to cytoplasmic streaming of the reporter in the former case, as was shown by using a photo-activatable GFP. Our findings indicate that a fungal mycelium is highly differentiated, especially when taking into account that hyphae in the exploration zone were exposed to the same nutritional conditions.
Basten, E.J.W.; Moers, A.P.H.A.; Ooyen, van A.J.J.; Schaap, P.J.
We have cloned a gene (papA) that encodes a prolyl aminopeptidase from Aspergillus niger. Homologous genes are present in the genomes of the Eurotiales A. nidulans, A. fumigatus and Talaromyces emersonii, but the gene is not present in the genome of the yeast Saccharomyces cerevisiae. Cell extracts
Jongh, Wian de
. Specielt Aspergillus niger er interessant i forbindelse med produktion af organiske syrer, idet denne organisme tolerer lavt pH, kan give høje produktudbytter, og kan give høje produktiviteter som allerede illustreret i anvendelsen af denne organisme i produktionen af citronsyre. Disse faktorer gør A...
Pedersen, Mads; Lauritzen, Henrik Klitgaard; Frisvad, Jens Christian
Twenty Aspergillus strains were evaluated for production of extracellular cellulolytic and xylanolytic activities. Aspergillus brasiliensis, A. niger and A. japonicus produced the highest xylanase activities with the A. brasiliensis and A. niger strains producing thermostable beta...
Pedersen, Mads; Lauritzen, H.K.; Frisvad, Jens Christian
Twenty Aspergillus strains were evaluated for production of extracellular cellulolytic and xylanolytic activities. Aspergillus brasiliensis, A. niger and A. japonicus produced the highest xylanase activities with the A. brasiliensis and A. niger strains producing thermostable beta...
Perrone, Giancarlo; Stea, Gaetano; Epifani, Filomena
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 β-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) of a population of A. niger strains isolated from grapes in Europe revealed the presence of a cryptic phylogenetic species...
... cellulase derived from Aspergillus niger. Carbohydrase and cellulase enzyme preparation derived from Aspergillus niger may be safely used in food in accordance with the following prescribed conditions: (a) Aspergillus niger is classified as follows: Class, Deuteromycetes; order, Moniliales; family,...
Punt Peter J
Full Text Available Abstract Background Human α1-proteinase inhibitor (α1-PI, also known as antitrypsin, is the most abundant serine protease inhibitor (serpin in plasma. Its deficiency is associated with development of progressive, ultimately fatal emphysema. Currently in the United States, α1-PI is available for replacement therapy as an FDA licensed plasma-derived (pd product. However, the plasma source itself is limited; moreover, even with efficient viral inactivation steps used in manufacture of plasma products, the risk of contamination from emerging viruses may still exist. Therefore, recombinant α1-PI (r-α1-PI could provide an attractive alternative. Although r-α1-PI has been produced in several hosts, protein stability in vitro and rapid clearance from the circulation have been major issues, primarily due to absent or altered glycosylation. Results We have explored the possibility of expressing the gene for human α1-PI in the filamentous fungus Aspergillus niger (A. niger, a system reported to be capable of providing more "mammalian-like" glycosylation patterns to secretable proteins than commonly used yeast hosts. Our expression strategy was based on fusion of α1-PI with a strongly expressed, secreted leader protein (glucoamylase G2, separated by dibasic processing site (N-V-I-S-K-R that provides in vivo cleavage. SDS-PAGE, Western blot, ELISA, and α1-PI activity assays enabled us to select the transformant(s secreting a biologically active glycosylated r-α1-PI with yields of up to 12 mg/L. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS analysis further confirmed that molecular mass of the r-α1-PI was similar to that of the pd-α1-PI. In vitro stability of the r-α1-PI from A. niger was tested in comparison with pd-α1-PI reference and non-glycosylated human r-α1-PI from E. coli. Conclusion We examined the suitability of the filamentous fungus A. niger for the expression of the human gene for α1-PI, a medium size
Aalbæk, Thomas; Reeslev, Morten; Jensen, Bo
In order to identify factors responsible for production of multiple forms of glucoamylase (GA) by Aspergillus niger Bo-1, the fungus was cultured in both complex and defined media in pH-controlled batch fermenters and chemostats. At all culture conditions three forms of GA were produced...... degradation of the GA forms at low pH. It was concluded that the observed modifications of the extracellular profile of GA isoforms in A. niger Bo-1 are due to changes in pH and medium composition....
Adriana Lozano Química
Full Text Available Endo-polymethylgalacturonase (endo-PMG EC 188.8.131.52 was produced by submerged fermentation using a local Aspergillus niger strain's Aspergillus niger spores (1xl05 spores/ml medium as inoculum. The only carbon source present in the fermentation medium was commercial citrus pectin. The enzyme was partially purified by precipitation with 20% ammonium sulphate, followed by chromatography in Sephadex G-75 and DEAE Sephadex A-50 columns. Pectinesterase yield was low in those fermentation conditions used. Fermentation crude extract presented two pH values (endo-PMG optimum pH 4.5 and 6.3. The enzymes were stable at pH values between 2.0 and 10.0. Optimum temperature was in the 40°C-45°C range. Enzymes became totally inactive at 70°C. It was also found that sodium ion concentrations greater than 0.1M inhibited endo-PMG.
Perrone, Giancarlo; Stea, Gaetano; Epifani, Filomena; Varga, János; Frisvad, Jens C; Samson, Robert A
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 β-tubulin (benA), calmodulin (CaM), and the translation elongation factor-1 alpha (TEF-1α) 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 B₂, and they also share the production of pyranonigrin A, tensidol B, funalenone, malformins, and naphtho-γ-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.
Schuster, E.; Dunn-Coleman, N.; Frisvad, Jens Christian
Aspergillus niger is one of the most important microorganisms used in biotechnology. It has been in use already for many decades to produce extracellular (food) enzymes and citric acid. In fact, citric acid and many A. niger enzymes are considered GRAS by the United States Food and Drug...... retrieval reasons and there is a taxonomical consensus based on molecular data that the only other common species closely related to A. niger in the Aspergillus series Nigri is A. tubingensis. A. niger, like other filamentous fungi, should be treated carefully to avoid the formation of spore dust. However...... Administration. In addition, A. niger is used for biotransformations and waste treatment. In the last two decades, A. niger has been developed as an important transformation host to over-express food enzymes. Being pre-dated by older names, the name A. niger has been conserved for economical and information...
Frisvad, Jens Christian; Nielsen, Kristian Fog; Mogensen, Jesper
Introduction: Fumonisins are toxic seconday metabolites from Fusarium verticillioides and other Fusaria, from Tolypocladium and Aspergillus niger 1,2. Being a generalist Aspergillus niger is the workhorse in a very large number of industrial applications, and is also a common contaminant in foods...... produced fumonisins in pure culture, so we tested whether they could produce fumonisins on citric acid production media in shake flasks, and they could indeed produce small amounts of fumonisins. Conclusions: Most strains of Aspergillus niger can produce fumonisins. In order to have entirely safe...
David, Helga; Åkesson, Mats Fredrik; Nielsen, Jens
The topology of central carbon metabolism of Aspergillus niger was identified and the metabolic network reconstructed, by integrating genomic, biochemical and physiological information available for this microorganism and other related fungi. The reconstructed network may serve as a valuable...
Mogensen, Jesper Mølgaard
Fumonisins is a well-studied group of mycotoxins, mainly produced in maize by Fusarium species. However with the recent discovery of a fumonisin production by Aspergillus niger, other food commodities are at risk, since A. niger is a ubiquitous contaminant of many food and feed products....... The objective of this thesis was to determine the significance and occurrence of fumonisins from Aspergillus niger in food, the frequency of fumonisin production in A. niger isolates, as well as studies of the effect of physiological factors affecting fumonisin production. Major findings in this context have...... been the ocumentation of the production of fumonisins in raisins and peanuts, and occurrence of A. niger derived fumonisins in retail wine and raisins. Physiological investigations have demonstrated that fumonisin production in A. niger occurs at temperatures between 20-37 °C. Three water activity...
Frisvad, Jens Christian; Larsen, Thomas Ostenfeld; Thrane, Ulf
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...
Benen, J.A.E.; Parenicova, L.; Kester, H.C.M.; Visser, J.
The Aspergillus niger plyA gene encoding pectate lyase A (EC 184.108.40.206) was cloned from a chromosomal EMBL4 library using the Aspergillus nidulans pectate lyase encoding gene [Dean, R. A., and Timberlake, W. E. (1989) Plant Cell 1, 275-284] as a probe. The plyA gene was overexpressed using a promoter
Shi, Changyou; He, Jun; Yu, Jie; Yu, Bing; Mao, Xiangbing; Zheng, Ping; Huang, Zhiqing; Chen, Daiwen
The nutrient digestibility and feeding value of rapeseed meal (RSM) for non-ruminant animals is poor due to the presence of anti-nutritional substances such as glucosinolate, phytic acid, crude fiber etc. In the present study, a solid state fermentation (SSF) using Aspergillus niger was carried out with the purpose of improving the nutritional quality of RSM. The chemical composition and physicochemical properties of RSM before and after fermentation were compared. To further understand possible mechanism of solid state fermentation, the composition of extracellular enzymes secreted by Aspergillus niger during fermentation was analysed using two-dimentional difference gel electrophoresis (2D-DIGE) combined with matrix assisted laser desorption ionization-time of flight-mass spectrometer (MALDI-TOF-MS). Results of the present study indicated that SSF had significant effects on chemical composition of RSM. The fermented rapeseed meal (FRSM) contained more crude protein (CP) and amino acid (AA) (except His) than unfermented RSM. Notably, the small peptide in FRSM was 2.26 time larger than that in unfermented RSM. Concentrations of anti-nutritional substrates in FRSM including neutral detergent fiber (NDF), glucosinolates, isothiocyanate, oxazolidithione, and phytic acid declined (P niger fermentation disrupted the surface structure, changed macromolecular organic compounds, and reduced the protein molecular weights of RSM substrate. Total proteins of raw RSM and FRSM were separated and 51 protein spots were selected for mass spectrometry according to 2D-DIGE map. In identified proteins, there were 15 extracellular hydrolases secreted by A. niger including glucoamylase, acid protease, beta-glucanase, arabinofuranosidase, xylanase, and phytase. Some antioxidant related enzymes also were identified. These findings suggested that A. niger is able to secrete many extracellular degradation enzymes (especially lignocellulosic hydrolyzing enzymes, acid proteases and phytase
García-Cela, E; Crespo-Sempere, A; Ramos, A J; Sanchis, V; Marin, S
The aim of this study was to evaluate the diversity of black aspergilli isolated from berries from different agroclimatic regions of Spain. Growth characterization (in terms of temperature and water activity requirements) of Aspergillus carbonarius, Aspergillus tubingensis and Aspergillus niger was carried out on synthetic grape medium. A. tubingensis and A. niger showed higher maximum temperatures for growth (>45 °C versus 40-42 °C), and lower minimum aw requirements (0.83 aw versus 0.87 aw) than A. carbonarius. No differences in growth boundaries due to their geographical origin were found within A. niger aggregate isolates. Conversely, A. carbonarius isolates from the hotter and drier region grew and produced OTA at lower aw than other isolates. However, little genetic diversity in A. carbonarius was observed for the microsatellites tested and the same sequence of β-tubulin gene was observed; therefore intraspecific variability did not correlate with the geographical origin of the isolates or with their ability to produce OTA. Climatic change prediction points to drier and hotter climatic scenarios where A. tubingensis and A. niger could be even more prevalent over A. carbonarius, since they are better adapted to extreme high temperature and drier conditions.
Baker, Scott E.
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.
Wang, Lu; Cao, Zhanglei; Hou, Li; Yin, Liuhua; Wang, Dawei; Gao, Qiang; Wu, Zhenqiang; Wang, Depei
Citric acid is produced by an industrial-scale process of fermentation using Aspergillus niger as a microbial cell factory. However, citric acid production was hindered by the non-fermentable isomaltose and insufficient saccharification ability in A. niger when liquefied corn starch was used as a raw material. In this study, A. niger TNA 101ΔagdA was constructed by deletion of the α-glucosidase-encoding agdA gene in A. niger CGMCC 10142 genome using Agrobacterium tumefaciens-mediated transformation. The transformants A. niger OG 1, OG 17, and OG 31 then underwent overexpression of glucoamylase in A. niger TNA 101ΔagdA. The results showed that the α-glucosidase activity of TNA 101ΔagdA was decreased by 62.5 % compared with CGMCC 10142, and isomaltose was almost undetectable in the fermentation broth. The glucoamylase activity of the transformants OG 1 and OG 17 increased by 34.5 and 16.89 % compared with that of TNA 101ΔagdA, respectively. In addition, for the recombinants TNA 101ΔagdA, OG 1 and OG 17, there were no apparent defects in the growth development. Consequently, in comparison with CGMCC 10142, TNA 101ΔagdA and OG 1 decreased the residual reducing sugar by 52.95 and 88.24 %, respectively, and correspondingly increased citric acid production at the end of fermentation by 8.68 and 16.87 %. Citric acid production was further improved by decreasing the non-fermentable residual sugar and increasing utilization rate of corn starch material in A. niger. Besides, the successive saccharification and citric acid fermentation processes were successfully integrated into one step.
Kutyła-Olesiuk, Anna; Wawrzyniak, Urszula E.; Ciosek, Patrycja; Wróblewski, Wojciech, E-mail: email@example.com
Highlights: • Citric acid fermentation process (production) by Aspergillus niger. • Qualitative/quantitative monitoring of standard culture and culture infected with yeast. • Electronic tongue based on potentiometric and voltammetric sensors. • Evaluation of the progress and the correctness of the fermentation process. • The highest classification abilities of the hybrid electronic tongue. - Abstract: Hybrid electronic tongue was developed for the monitoring of citric acid production by Aspergillus niger. The system based on various potentiometric/voltammetric sensors and appropriate chemometric techniques provided correct qualitative and quantitative classification of the samples collected during standard Aspergillus niger culture and culture infected with yeast. The performance of the proposed approach was compared with the monitoring of the fermentation process carried out using classical methods. The results obtained proved, that the designed hybrid electronic tongue was able to evaluate the progress and correctness of the fermentation process.
Shiv Mohan Singh,
Full Text Available Many filamentous fungi were isolated from the soils of Ny-Ålesund, Spitsbergen, Svalbard, and were screened in vitro for their phosphate solubilizing ability. Two strains of Aspergillus niger showed good tricalcium phosphate (TCP solubilizing ability in Pikovskaya's medium. The TCP solubilization index was calculated at varying levels of pH and temperatures. The ability of Aspergillus niger strain-1 to solubilize and release inorganic-P was 285 µg ml–1, while Aspergillus niger strain-2 solubilized 262 µg ml–1 from 0.5% TCP after seven days. This is the first report of TCP solubilization by Arctic strains that may serve as very good phosphate solubilizers in the form of biofertilizer.
Full Text Available The influence of inoculum preparation on Aspergillus awamori morphology, broth rheology and glucoamylase synthesis in submerged cultures was investigated. A series of runs were performed in fermenters, using initial total reducing sugar concentrations of 20 g/L and 80 g/L. The inocula were prepared in a rotary shaker, at 35oC and 200 rev/min, using a spore concentration of 9.2 x 105 spores/mL and varying both cultivation time and medium pH during the spore germination step. Three types of inocula were used: inoculum cultivated for 24 hours at an initial pH of 5.0, and inocula cultivated for 7 hours at both a pH of 2.5 and a pH of 5.5. Regarding glucoamylase production, the inoculum which provided the best results was shaker cultivated for 7 hours at a pH of 2.5. This inoculum produced glucoamylase of about 1,221 U/L in the fermenter, which was between 20% and 30% higher than those obtained using other inocula.
Andersen, Mikael Rørdam; Giese, Malene; de Vries, Ronald P.
of 188 genes coding for carbohydrate-active enzymes from Aspergillus niger, thus forming an analysis framework, which can be queried. Combination of this information network with gene expression analysis on mono-and polysaccharide substrates has allowed elucidation of concerted gene expression from...... of carbohydrate-active enzymes. Applying this network-based approach, we provide the first genome-scale characterization of all genes coding for carbohydrate-active enzymes identified in A. niger....
Vinck, Arman; de Bekker, Charissa; Ossin, Adam; Ohm, Robin A; de Vries, Ronald P; Wösten, Han A B
Colonization of a substrate by fungi starts with the invasion of exploring hyphae. These hyphae secrete enzymes that degrade the organic material into small molecules that can be taken up by the fungus to serve as nutrients. We previously showed that only part of the exploring hyphae of Aspergillus niger highly express the glucoamylase gene glaA. This was an unexpected finding since all exploring hyphae are exposed to the same environmental conditions. Using GFP as a reporter, we here demonstrate that the acid amylase gene aamA, the α-glucuronidase gene aguA, and the feruloyl esterase gene faeA of A. niger are also subject to heterogenic expression within the exploring mycelium. Coexpression studies using GFP and dTomato as reporters showed that hyphae that highly express one of these genes also highly express the other genes encoding secreted proteins. Moreover, these hyphae also highly express the amylolytic regulatory gene amyR, and the glyceraldehyde-3-phosphate dehydrogenase gene gpdA. In situ hybridization demonstrated that the high expressers are characterized by a high 18S rRNA content. Taken together, it is concluded that two subpopulations of hyphae can be distinguished within the exploring mycelium of A. niger. The experimental data indicate that these subpopulations differ in their transcriptional and translational activity.
Kutyła-Olesiuk, Anna; Wawrzyniak, Urszula E; Ciosek, Patrycja; Wróblewski, Wojciech
Hybrid electronic tongue was developed for the monitoring of citric acid production by Aspergillus niger. The system based on various potentiometric/voltammetric sensors and appropriate chemometric techniques provided correct qualitative and quantitative classification of the samples collected during standard Aspergillus niger culture and culture infected with yeast. The performance of the proposed approach was compared with the monitoring of the fermentation process carried out using classical methods. The results obtained proved, that the designed hybrid electronic tongue was able to evaluate the progress and correctness of the fermentation process.
Nikolaev, I.; Mathieu, M.; Vondervoort, van de P.J.I.; Visser, J.; Felenbok, B.
The inducible and strongly expressed alcA gene encoding alcohol dehydrogenase I from Aspergillus nidulans was transferred together with the activator gene alcR, in the industrial fungus Aspergillus niger. This latter organism does not possess an inducible alc system but has an endogenously constitut
This thesis describes a molecular study of the genetics ofL-arabinan degradation in Aspergillus niger and Aspergillus nidulans. These saprophytic hyphal fungi produce an extracellular hydrolytic enzyme system to depolymerize the plant cell wall polysaccharideL<
Graaff, de L.H.
Dit proefschrift "Het pyruvaat kinase gen en zijn expressie in Aspergillus nidulans en Aspergillus niger " beschrijft het onderzoek naar de structuur en expressie van het pyruvaat kinase gen in deze schimmels.De doelstelling van dit onderzoek was de opheldering van de genstructuur van het pyruvaat k
Jeon, Bo Young; Kim, Dae Hee; Na, Byung Kwan; Ahn, Dae Hee; Park, Doo Hyun
When cultivated aerobically, Aspergillus niger hyphae produced extracellular glucoamylase, which catalyzes the saccharification of unliquified potato starch into glucose, but not when grown under anaerobic conditions. The Km and Vmax of the extracellular glucoamylase were 652.3 mg starch l-1 and 253.3 mg glucose l-1 min-1, respectively. In mixed culture of A. niger and Saccharomyces cerevisiae, oxygen had a negative influence on the alcohol fermentation of yeast, but activated fungal growth. Therefore, oxygen is a critical factor for ethanol production in the mixed culture, and its generation through electrolysis of water in an electrochemical bioreactor needs to be optimized for ethanol production from starch by coculture of fungal hyphae and yeast cells. By applying pulsed electric fields (PEF) into the electrochemical bioreactor, ethanol production from starch improved significantly: Ethanol produced from 50 g potato starch l-1 by a mixed culture of A. niger and S. cerevisiae was about 5 g l-1 in a conventional bioreactor, but was 9 g l-1 in 5 volts of PEF and about 19 g l-1 in 4 volts of PEF for 5 days.
Biesebeke, R. te; Biezen, N. van; Vos, W.M. de; Hondel, C.A.M.J.J. van den; Punt, P.J.
Solid-state fermentation (SSF) with Aspergillus oryzae results in high levels of secreted protein. However, control mechanisms of gene expression in SSF have been only poorly studied. In this study we show that both glucoamylase (glaB) and protease (alpA, nptB) genes are highly expressed during surf
Krasevec, N.; Hondel, C.A.M.J.J. van den; Komel, R.
A gene-fusion expression strategy was applied for the heterologous expression of hTNF-α in A. niger AB1.13. The TNF-α gene was fused with the A. niger glucoamylase GII form as a carrier-gene, behind its transcription control and secretion signal. The protein was expressed in the cells in the form of
Nitsche, Benjamin Manuel
This study investigated carbon starvation in the filamentous fungus Aspergillus niger during submerged cultivation in bioreactor batch cultures. The work described in this thesis can be discussed as follows: (I) Establishment of computational resources for omics data analysis and interpretation in c
A wide variety of enzymes is commonly used in industrial applications, for instance in the food and feed industry. Because of its exceptionally high protein secretion capacity, one of the preferred hosts for the production of such enzymes is the filamentous fungus Aspergillus niger. The research des
Basten, E.J.W.; Dekker, P.J.T.; Schaap, P.J.
A novel enzyme with a specific phenylalanine aminopeptidase activity (ApsC) from Aspergillus niger (CBS 120.49) has been characterized. The derived amino acid sequence is not similar to any previously characterized aminopeptidase sequence but does share similarity with some mammalian acyl-peptide hy
Teertstra, Wieke R.; Tegelaar, Martin; Dijksterhuis, Jan; Golovina, Elena A.; Ohm, Robin A.; Wösten, Han A.B.
Conidia of Aspergillus niger are produced on conidiophores. Here, maturation of conidia on these asexual reproductive structures was studied. Pigmented conidia that had developed on conidiophores for 2, 5, and 8 days were similarly resistant to heat and were metabolically active as shown by CO2 rele
Conesa, A.; Hondel, C.A.M.J.J. van den; Punt, P.J.
To get insight into the limiting factors existing for the efficient production of fungal peroxidase in filamentous fungi, the expression of the Phanerochaete chrysosporium lignin peroxidase H8 (lipA) and manganese peroxidase (MnP) H4 (mnp1) genes in Aspergillus niger has been studied. For this purpo
Petersen, Lene Maj; Holm, Dorte Koefoed; Knudsen, Peter Boldsen
Four new yanuthone analogs (1–4) were isolated from the filamentous fungus Aspergillus niger. The structures of the new compounds were elucidated on the basis of UHPLC-DAD-HRMS data and one-dimensional and two-dimensional NMR spectroscopy. Labeling studies with 13C8-6-methylsalicylic acid...
Jongh, Wian de; Nielsen, Jens
The effect of inserting genes involved in the reductive branch of the tricarboxylic acid (TCA) cycle on citrate production by Aspergillus niger was evaluated. Several different genes were inserted individually and in combination, i.e. malate dehydrogenase (mdh2) from Saccharomyces cerevisiae, two...
Ferracin, L.M.; Frisvad, Jens Christian; Taniwaki, M.H.
We analyzed the genetic relationships between 51 fungal isolates previously identified as A. niger aggregate, obtained from dried fruit samples from worldwide origin and 7 A. tubingensis obtained from Brazilian coffee beans samples. Greater fungal diversity was found in black sultanas. Aspergillus...
Sutherland, John B; Heinze, Thomas M; Schnackenberg, Laura K; Freeman, James P; Williams, Anna J
Cultures of Aspergillus niger NRRL-599 in fluid Sabouraud medium were grown with quinazoline and phthalazine for 7 days. Metabolites were purified by high-performance liquid chromatography and identified by mass spectrometry and proton nuclear magnetic resonance spectroscopy. Quinazoline was oxidized to 4-quinazolinone and 2,4-quinazolinedione, and phthalazine was oxidized to 1-phthalazinone.
Meijer, Susan Lisette; De Jongh, Willem Adriaan; Olsson, Lisbeth
The acuB gene of Aspergillus niger is an ortholog of facB in Aspergillus nidulans. Under carbon-repression conditions, facB is repressed, thereby preventing acetate metabolism when the repressing carbon source is present. Even though facB is reported to be repressed directly by CreA, it is believed...... that a basal level of FacB activity exists under glucose-repressive conditions. In the present study, the effect of deletion of acuB on the physiology of A. niger was assessed. Differences in organic acid and acetate production, enzyme activities and extracellular amino and non-amino organic acid production...... were determined under glucose-repressing and -derepressing conditions. Furthermore, consumption of alternative carbon sources (e.g. xylose, citrate, lactate and succinate) was investigated. It was shown that AcuB has pleiotropic effects on the physiology of A. niger. The results indicate that metabolic...
Keni, Sarita; Punekar, Narayan S
Aspects of manganese metabolism during normal and acidogenic growth of Aspergillus niger were explored. Arginase from this fungus was a Mn[II]-enzyme. The contribution of the arginase protein towards A. niger manganese metabolism was investigated using arginase knockout (D-42) and arginase over-expressing (ΔXCA-29) strains of A. niger NCIM 565. The Mn[II] contents of various mycelial fractions were found in the order: D-42 strain niger mycelia harvested from acidogenic growth media contain substantially less Mn[II] as compared to those from normal growth media. Nevertheless, acidogenic mycelia harbor considerable Mn[II] levels and a functional arginase. Altered levels of mycelial arginase protein did not significantly influence citric acid production. The relevance of arginase to cellular Mn[II] pool and homeostasis was evaluated and the results suggest that arginase regulation could occur via manganese availability.
Full Text Available Triticale (Triticosecale, Wittmak an important industrial crop, with high grain yield, containing high amounts of starch, proteins and also major and minor mineral elements, is not sufficiently utilized yet. The simultaneous production of α-amylase and glucoamylase isoforms by Aspergillus niger on triticale grains, without any nutritive supplements, has been developed, optimized and scaled up 10 fold for the first time. The specific combination of examined effects led to the production of a novel glucoamylase isoform. Reduction of particle size, increase of oxygen availability and substrate height lead to increase of amylases production of 30%. Reduction of relative humidity from 65% to 30% increased glucoamylase production 2 times and α-amylase production for 30%. Peak production of α-amylase (158 U/g and glucoamylase (170 U/g were obtained in erlenmayers and in scaled-up trays. The obtained A. niger amylase cocktail was more efficient in raw starch hydrolysis from wheat flour, 29% more efficient in glucose formation and 10% more efficient in total reducing sugar formation, than commercially available amylase cocktail SAN Super 240L widely used in industry. [Projekat Ministarstva nauke Republike Srbije, br. 172048
Silva, E.P.; Barros Junior, L.M.; Duarte, M.M.L.; Macedo, G.R. [Universidade Federal do Rio Grande do Norte, Natal, RN (Brazil)]. E-mail: firstname.lastname@example.org
Biosorption is a property of certain types of inactive, dead, microbial biomass to bind and concentrate heavy metals from even very dilute aqueous solutions. Biomass exhibits this property, acting just as a chemical substance, as an ion exchanger of biological origin. It is particularly the cell wall structure of certain algae, fungi and bacteria which was found responsible for this phenomenon. Some of the biomass types come as a waste by-product of large-scale industrial fermentations (the mold Rhizopus or the bacterium Bacillus subtilis). Other metal-binding biomass types, certain abundant seaweeds (particularly brown algae e.g. Sargassum, Ecklonia), can be readily collected from the oceans. These biomass types, serving as a basis for metal biosorption processes, can accumulate in excess of 25% of their dry weight in deposited heavy metals: Pb, Cd, U, Cu, Zn, even Cr and others. Sorption experiments using the Aspergillus niger fungus for cadmium removal were carried out to study the factors influencing and optimizing the biosorption of this metal. The effects of pH, time, biomass concentration, and initial concentration of the heavy metal on the rate of metallic biosorption were examined. (author)
Gladden, John Michael
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.
Levin Chucrel, A.M.
The aim of this Thesis was to study genome-wide gene expression in colonies of A. niger and to relate this to nutrient availability, growth, and secretion. Maltose and xylose were chosen as carbon sources for this study. These compounds result in different sets of extracellular enzymes. In Chapter 2
金浩; 李祖义; 王清
Biocatalytic resolution of racemic para-nitrostyrene oxide was accomplished by employing the epoxide hydrolases from the whole cells of several Aspergillus niger (A. niger) strains. In the cases investigated, excellent selectivity was achieved with such strains as A, niger 5450, A. niger 5320.
Full Text Available The nutrient digestibility and feeding value of rapeseed meal (RSM for non-ruminant animals is poor due to the presence of anti-nutritional substances such as glucosinolate, phytic acid, crude fiber etc. In the present study, a solid state fermentation (SSF using Aspergillus niger was carried out with the purpose of improving the nutritional quality of RSM. The chemical composition and physicochemical properties of RSM before and after fermentation were compared. To further understand possible mechanism of solid state fermentation, the composition of extracellular enzymes secreted by Aspergillus niger during fermentation was analysed using two-dimentional difference gel electrophoresis (2D-DIGE combined with matrix assisted laser desorption ionization-time of flight-mass spectrometer (MALDI-TOF-MS. Results of the present study indicated that SSF had significant effects on chemical composition of RSM. The fermented rapeseed meal (FRSM contained more crude protein (CP and amino acid (AA (except His than unfermented RSM. Notably, the small peptide in FRSM was 2.26 time larger than that in unfermented RSM. Concentrations of anti-nutritional substrates in FRSM including neutral detergent fiber (NDF, glucosinolates, isothiocyanate, oxazolidithione, and phytic acid declined (P < 0.05 by 13.47, 43.07, 55.64, 44.68 and 86.09%, respectively, compared with unfermented RSM. A. niger fermentation disrupted the surface structure, changed macromolecular organic compounds, and reduced the protein molecular weights of RSM substrate. Total proteins of raw RSM and FRSM were separated and 51 protein spots were selected for mass spectrometry according to 2D-DIGE map. In identified proteins, there were 15 extracellular hydrolases secreted by A. niger including glucoamylase, acid protease, beta-glucanase, arabinofuranosidase, xylanase, and phytase. Some antioxidant related enzymes also were identified. These findings suggested that A. niger is able to secrete many
Hofmann, Gerald; Diano, Audrey; Nielsen, Jens
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...... behind the strong gpdA promoter from Aspergillus nidulans. Analysis of secreted metabolites, oxygen uptake, CO2 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...
Mirhendi, H; Zarei, F; Motamedi, M; Nouripour-Sisakht, S
This work aimed to identify the species distribution of common clinical and environmental isolates of black Aspergilli based on simple restriction fragment length polymorphism (RFLP) analysis of the β-tubulin gene. A total of 149 clinical and environmental strains of black Aspergilli were collected and subjected to preliminary morphological examination. Total genomic DNAs were extracted, and PCR was performed to amplify part of the β-tubulin gene. At first, 52 randomly selected samples were species-delineated by sequence analysis. In order to distinguish the most common species, PCR amplicons of 117 black Aspergillus strains were identified by simple PCR-RFLP analysis using the enzyme TasI. Among 52 sequenced isolates, 28 were Aspergillus tubingensis, 21 Aspergillus niger, and the three remaining isolates included Aspergillus uvarum, Aspergillus awamori, and Aspergillus acidus. All 100 environmental and 17 BAL samples subjected to TasI-RFLP analysis of the β-tubulin gene, fell into two groups, consisting of about 59% (n=69) A. tubingensis and 41% (n=48) A. niger. Therefore, the method successfully and rapidly distinguished A. tubingensis and A. niger as the most common species among the clinical and environmental isolates. Although tardy, the Ehrlich test was also able to differentiate A. tubingensis and A. niger according to the yellow color reaction specific to A. niger. A. tubingensis and A. niger are the most common black Aspergillus in both clinical and environmental isolates in Iran. PCR-RFLP using TasI digestion of β-tubulin DNA enables rapid screening for these common species.
L.M. Barros Júnior
Full Text Available Sorption experiments using the Aspergillus niger fungus for cadmium removal were carried out to study the factors influencing and optimizing the biosorption of this metal. The effects of pH, time, biomass concentration, and initial concentration of the heavy metal on the rate of metallic biosorption were examined. An experimental design was also used to determine the values of the under study variables that provided the greatest biosorption efficiency. A technique for biomass recovery was also developed with the objective of determining the capacity of the regenerated biomass to biosorb the metals in solution. This research proved that with a pH of 4.75, a biomass concentration of 0.7 g/L, and a heavy metal concentration varying between 5 and 10 mg/L a biosorption process of biosorption with Aspergillus niger could be successfully used for heavy metal removal from oil field water in the oil industry.
QI YANG; JIAN-LONG WANG; ZHI XING
Objective To investigate the removal of cadmium from aqueous solution by waste fungal biomass of Aspergillus niger, originated from citric acid fermentation industry. Methods Batch adsorption test was used to study the biosorption equilibrium and isotherm. The Cd2+ concentration was measured with atomic adsorption spectrophotometer (AAS) HITACHI 180-80. Results The biosorption achieved equilibrium within 30 min. The adsorption isotherm could be described by Freundlich adsorption model, and the constants KF and 1/n were determined to be 2.07 and 0.18, respectively, and the correlation efficiency was 0.97. The optimal pH for Cd adsorption was 6.0. The cadmium-laden biomass could be effectively regenerated using 0.1 N HCl. Conclusion The waste biomass of Aspergillus niger, a by-product of fermentation industry, is a potential biosorbent for the removal of cadmium from aqueous solution.
Selvaggi, Thomas A; Walco, Jeremy P; Parikh, Sujal; Walco, Gary A
We sought to determine if sufficient redundancy exists between specific IgE testing for Aspergillus fumigatus and Aspergillus niger to eliminate one of the assays in determining Aspergillus hypersensitivity. We reviewed regional laboratory results comparing A fumigatus-specific IgE with A niger-specific IgE using the Pharmacia UniCAP system (Pharmacia, Kalamazoo, MI). By using the Fisher exact test as an index of concordance among paired results, we showed a significant difference between 109 paired samples for the presence of specific IgE to A fumigatus and A niger (P niger; no specimen was positive for A niger and negative for A fumigatus. We conclude that A fumigatus-specific IgE is sufficient to detect Aspergillus hypersensitivity. The assay for A niger-specific IgE is redundant, less sensitive, and unnecessary if the assay for specific IgE for A fumigatus is performed.
Veen, van der P.
The first aim of this thesis was to get a better understanding of the properties and the induction features of arabinan degrading enzymes and enzymes involved in the intracellular L-arabinose catabolic pathway in Aspergillus niger. The second aim was to understand the which role carbon catabolite re
Goldman Gustavo H
Full Text Available Abstract Background Considering that the costs of cellulases and hemicellulases contribute substantially to the price of bioethanol, new studies aimed at understanding and improving cellulase efficiency and productivity are of paramount importance. Aspergillus niger has been shown to produce a wide spectrum of polysaccharide hydrolytic enzymes. To understand how to improve enzymatic cocktails that can hydrolyze pretreated sugarcane bagasse, we used a genomics approach to investigate which genes and pathways are transcriptionally modulated during growth of A. niger on steam-exploded sugarcane bagasse (SEB. Results Herein we report the main cellulase- and hemicellulase-encoding genes with increased expression during growth on SEB. We also sought to determine whether the mRNA accumulation of several SEB-induced genes encoding putative transporters is induced by xylose and dependent on glucose. We identified 18 (58% of A. niger predicted cellulases and 21 (58% of A. niger predicted hemicellulases cellulase- and hemicellulase-encoding genes, respectively, that were highly expressed during growth on SEB. Conclusions Degradation of sugarcane bagasse requires production of many different enzymes which are regulated by the type and complexity of the available substrate. Our presently reported work opens new possibilities for understanding sugarcane biomass saccharification by A. niger hydrolases and for the construction of more efficient enzymatic cocktails for second-generation bioethanol.
Nikolaev, I; Mathieu, M; van de Vondervoort, P; Visser, J; Felenbok, B
The inducible and strongly expressed alcA gene encoding alcohol dehydrogenase I from Aspergillus nidulans was transferred together with the activator gene alcR, in the industrial fungus Aspergillus niger. This latter organism does not possess an inducible alc system but has an endogenously constitutive lowly expressed alcohol dehydrogenase activity. The overall induced expression of the alcA gene was of the same order in both fungi, as monitored by alcA transcription, alcohol dehydrogenase activity and heterologous expression of the reporter enzyme, beta-glucuronidase. However, important differences in the pattern of alcA regulation were observed between the two fungi. A high basal level of alcA transcription was observed in A. niger resulting in a lower ratio of alcA inducibility. This may be due to higher levels of the physiological inducer of the alc regulon, acetaldehyde, from general metabolism in A. niger which differs from that of A. nidulans.
Jens C Frisvad
Full Text Available 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 (B(2, B(4, and B(6 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.
Lara Munique Ferracin
Full Text Available We analyzed the genetic relationships between 51 fungal isolates previously identified as A. niger aggregate, obtained from dried fruit samples from worldwide origin and 7 A. tubingensis obtained from Brazilian coffee beans samples. Greater fungal diversity was found in black sultanas. Aspergillus niger sensu stricto was the most prevalent species. It was found in all fruit substrates of all geographical origins. Based on Random Amplification of Polymorphic DNA (RAPD and β-tubulin sequences data two groups of A. niger were found. In spite of the small number of isolates from Group IV an association between extrolite patterns and molecular clustering is speculated. A. tubingensis were the second most frequent species and this species were clearly subdivided into two groups. The finding of two groups for A. tubingensis strains could not yet explain the contradictions found in the literature about the capability this species for ochratoxin production, because both of them were formed by only non-ochratoxin-producing strains.Neste trabalho foi analisada a relação genética entre 51 isolados obtidos de amostras de frutas secas provenientes de diferentes regiões do previamente identificados como pertencentes ao agregado A. niger e 7 isolados de Aspergillus tubingensis obtidos de amostras de café do Brasil. Maior diversidade fúngica foi encontrada em uvas passas escuras. Aspergillus niger sensu stricto foi a espécie mais frequente. Esta espécie foi encontrada em todos os substratos e origens geográficas analisadas. Baseando-se nos dados de Polimorfismo de DNA Amplificado ao Acaso (RAPD e sequências de nucleotídeos do gene da β-tubulina, dois grupos de A. niger foram observados. Apesar do pequeno número de isolados do grupo IV uma associação entre padrão de extrólitos e agrupamento molecular foi encontrada. A. tubingensis foi a segunda espécie mais frequente e foi claramente subdivida em dois grupos. Como os grupos de A. tubingensis s
Li, A.; Pfelzer, N.; Zuijderwijk, R.; Brickwedde, A.; Zeijl, C. van; Punt, P.
Aspergillus niger has an extraordinary potential to produce organic acids as proven by its application in industrial citric acid production. Previously, it was shown that expression of the cis-aconitate decarboxylase gene (cadA) from Aspergillus terreus converted A. niger into an itaconic acid produ
Toniazzo, Geciane; de Oliveira, Débora; Dariva, Cláudio; Oestreicher, Enrique Guillermo; Antunes, Octávio A C
The main objective of this work was to investigate the biotransformations of (-)alpha-pinene, (-)beta-pinene, and (+) limonene by Aspergillus niger ATCC 9642. The culture conditions involved--concentration of cosolvent (EtOH), substrate applied, and sequential addition of substrates were--investigated. Adaptation of the precultures with small amounts of substrate was also studied. The experiments were performed in conical flasks with liquid cultures. This strain of A. niger was able to convert only (-)beta-pinene into alpha-terpineol. An optimum conversion of (-)beta-pinene into alpha-terpineol of about 4% was obtained when the substrate was applied as a diluted solution in EtOH and sequential addition of substrate was used.
Full Text Available Tannery waste water is characterized by highly toxic ammonium, sulfates, surfactants, acids, dyes, sulfonated oils and organic substances, including natural or synthetic tannins. This study was designed to study the potential of Aspergillus niger for bioremediation of tannery effluent. Addition of glucose as a carbon source in the tannery effluent encouraged the growth of A. niger but there was no change in physico-chemical parameters. The toxic effects were mostly reduced after treatment when 20% mineral salt medium was added in tannery effluent. Colour, COD, TS, TDS, TSS, chlorides, sulfides and chromium reduction were 71.9%, 72.1%, 69.0%, 65.0%, 68.1%, 66.8%, 65.7% and 57.8%, respectively.
S. O. Kareem; Akpan, I.; Alebiowu, O. O.
A solid state fermentation was developed for citric acid production from pineapple waste by Aspergillus niger KS-7. The medium was supplemented with different concentration of glucose, sucrose, ammonium nitrate and ammonium phosphate. It was found that pineapple waste with 15% (w/v) sucrose and ammonium nitrate (0.25% w/v) gave the optimum citric acid secretion (60.61 g/kg) in the presence of methanol (2% v/v) when fermented for 5 days at 30 °C with the initial moisture content of 65%. The ...
HUANG Hui-li; LIN Wen-luan; LIN Jian-ming
Chitin from cell walls of Aspergillus Niger mycelium was prepared. A new method for the preparation of high deacetylation degree chitosan was studied in a dilute sodium hydroxide solution at a high pressure. The experimental results indicate that the deacetylation degree of the chitosan can reach 80% under the condition of a 5.00 mol/L sodium hydroxide solution at 0.1 MPa of pressure for 1 h. This method shows the advantages of the applications in the industry production and environment protection.
Wang Jianhua(王建华); Teng Da; Yao Yi; Yang Yalin; Zhang Fan
An endoinulinase gene from Aspergillus niger 9891 (CGMCC0991) has been expressed in Pichia pastoris GS115 using pPIC9 vector. The recombinant endoinulinase was highly expressed and the optimization of the expression in a 7 liter of fermentor has been investigated. In fermented broth, the concentration of protein secreted is 2.15 mg/ml. The activity of endoinulinase is 1501 U/ml with sucrose as substrate and 291 U/ml with inulin as substrate, 105 and 273 times higher than that from the original strain respectively.
Full Text Available Abstract 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
Hemdan, R. Elmitwalli; Fatma, Helmi M.; Rizk, Mohammed A.; Hagrassy, Abeer F.
Biodeterioration of mural paintings by Aspergillus niger and Aspergillus flavus Fungi has been proved in different mural paintings in Egypt nowadays. Several researches have studied the effect of fungi on mural paintings, the mechanism of interaction and methods of control. But none of these researches gives us the solution without causing a side effect. In this paper, for the first time, a recent treatment by antibiotic "6 penthyl α pyrone phenol" was applied as a successful technique for elimination of Aspergillus niger and Aspergillus flavus. On the other hand, it is favorable for cleaning Surfaces of Murals executed by tembera technique from the fungi metabolism which caused a black pigments on surfaces.
Sandana Mala, John Geraldine; Unni Nair, Balachandran; Puvanakrishnan, Rengarajulu
Chromium toxicity is of prime concern due to chrome tanning processes in the leather sector. Chrome tanning results in the discharge of toxic levels of chromium causing pollution hazards. Chromium levels of Cr(III) and Cr(VI) were high above permissible limits in chrome samples after chrome tanning. The potential of Aspergillus niger MTCC 2594 to accumulate chromium as well as its biosorption capacity is investigated in this study. Bioaccumulation of Cr(III) and Cr(VI) in the spent chrome liquor has resulted in a 75-78% reduction of the initial Cr content in 24-36 h. A. niger biomass is found to be very effective in the biosorption of Cr(III) and Cr(VI) in spent chrome liquor. Maximum adsorption of 83% for biosorption of Cr(III) at 48 h and 79% of Cr(VI) at 36 h in spent chrome liquor is observed. The biosorption characteristics fit well with Langmuir and Freundlich isotherms and the adsorption parameters are evaluated. The biosorption of Cr also follows Lagergren kinetics. A. niger biomass is effectively used for the biosorption of chromium with 79-83% Cr removal in 36-48 h.
vanKuyk, Patricia A; Benen, Jaques A E; Wösten, Han A B; Visser, Jaap; de Vries, Ronald P
AmyR is commonly considered a regulator of starch degradation whose activity is induced by the presence of maltose, the disaccharide building block of starch. In this study, we demonstrate that the role of AmyR extends beyond starch degradation. Enzyme activity assays, genes expression analysis and growth profiling on D-glucose- and D-galactose-containing oligo- and polysaccharides showed that AmyR regulates the expression of some of the Aspergillus niger genes encoding α- and β-glucosidases, α- and β- galactosidases, as well as genes encoding α-amlyases and glucoamylases. In addition, we provide evidence that D-glucose or a metabolic product thereof may be the inducer of the AmyR system in A. niger and not maltose, as is commonly assumed.
Coutinho, Pedro M.; Andersen, Mikael Rørdam; Kolenova, Katarina
The plant polysaccharide degradative potential of Aspergillus nidulans was analysed in detail and compared to that of Aspergillus niger and Aspergillus oryzae using a combination of bioinformatics, physiology and transcriptomics. Manual verification indicated that 28.4% of the A. nidulans ORFs an...
Reddy, M Sudhakara; Kumar, Surender; Babita, K; Reddy, M S
Three isolates of Aspergillus tubingensis and two isolates of Aspergillus niger isolated from rhizospheric soils were tested on solubilization of different rock phosphates. All the isolates of Aspergillus were capable of solubilizing all the natural rock phosphates. A. tubingensis (AT1) showed maximum percent solubilization in all the rock phosphates tested in this study when compared to other isolates. This isolate also showed highest phosphorus (P) solubilization when grown in the presence of 2% of rock phosphate. A. tubingensis (AT1) seems to be more efficient in solubilization of rock phosphates compared to other isolates reported elsewhere. This is the first report of rock phosphate solubilization by A. tubingensis and might provide an efficient large scale biosolubilization of rock phosphates intended for P fertilizer.
Although it has been widely used as a feed supplement to reduce manure phosphorus pollution of swine and poultry, Aspergillus niger PhyA phytase is unable to withstand heat inactivation during feed pelleting. Crystal structure comparisons with its close homolog, the thermostable Aspergillus fumigatu...
Yeo S., L.; Shazilah, K.; Suhaila, S.; Abu Bakar F., D.; Murad A. M., A.
Genomic data mining was carried out and revealed a total of seventeen β-glucosidases in filamentous fungi Aspergillus niger. Two of them belonged to glycoside hydrolase family 1 (GH1) while the rest belonged to genes in family 3 (GH3). These proteins were then named according to the nomenclature as proposed by the International Union of Biochemistry (IUB), starting from the lowest pI and glycoside hydrolase family. Their properties were predicted using various bionformatic tools showing the presence of domains for signal peptide and active sites. Interestingly, one particular domain, PA14 (protective antigen) was present in four of the enzymes, predicted to be involved in carbohydrate binding. A phylogenetic tree grouped the two glycoside hydrolase families with GH1 and GH3 related organisms. This study showed that the various domains present in these β-glucosidases are postulated to be crucial for the survival of this fungus, as supported by other analysis.
Li, Xiao-Bin; Li, Yue-Lan; Zhou, Jin-Chuan; Yuan, Hui-Qing; Wang, Xiao-Ning; Lou, Hong-Xiang
One new diketopiperazine heterodimer, asperazine A (1), and eight known compounds, asperazine (2), cyclo(d-Phe-l-Trp) (3), cyclo(l-Trp-l-Trp) (4), 4-(hydroxymethyl)-5,6-dihydro-pyran-2-one (5), walterolactone A (6), and campyrones A-C (7-9), were isolated from an endophytic fungus Aspergillus niger. Their structures were determined unequivocally on the basis of extensive spectroscopic data analysis. This is the first report of the presence of compound 3 as a natural product. Cytotoxicity test against human cancer cell lines PC3, A2780, K562, MBA-MD-231, and NCI-H1688 revealed that compounds 1 and 2 had weak activities.
Gretty K. Villena
Full Text Available An initial profiling of the intracellular proteome of Aspergillus niger ATCC 10864 biofilm cultures developed on polyester cloth was carried out by using 2D-PAGE and MS-TOF analysis and it was compared to the proteome of conventionally grown free-living submerged cultures. A number of 2D-PAGE protein spots from both types of cultures were subjected to MS-TOF analysis and data interrogation of the NCBI nr database available for this species. Proteomic maps showed different expression patterns in both culture systems with differentially expressed proteins in each case. In biofilm cultures, 19% and 32% of the selected protein spots were over- expressed and differentially expressed, respectively. On the contrary, in free-living cultures, 44% and 7% of the selected protein spots were over-expressed and differentially expressed, respectively. Although preliminary, results presented in this paper show that there are significant differences between the proteomes of A. niger biofilm and free-living mycelia. It seems that cell adhesion is the most important stimulus responsible for biofilm development which is the basis of Surface Adhesion Fermentation.
Kasahara, H; Miyazawa, M; Kameoka, H
Microbial transformation of (+/-)-eudesmin by Aspergillus niger was investigated. Enantioselective accumulation of (--)-pinoresinol was shown through O-demethylation of (+/-)-eudesmin. This fungus O- demethylated both enantiomers of eudesmin, but the conversion rates for each enantiomer were clearly different.
OMOJASOLA PATRICIA FOLAKEMI
Full Text Available Accumulation of large quantities of agricultural residues results in deterioration of the environment and biomass loss which could be processed to yield value-added products like fuels and a variety of acids. The quest for a solution led to the fermentation of Ipomoea batatas using fungi. Aspergillus niger (ATCC 16404 and Aspergillus terreus (ATCC 20542 were used to ferment sweet potato peel (SPP, an agro-based waste. The physico-chemical analysis of the SPP was carried out. SPP was dried, ground, pre-treated with alkali and steam, re-dried and used as substrate in media containing mineral salt medium and inocula of A. niger and A. terreus. Fermentation was submerged at pH 5.0; 10% substrate concentration; 10 mL inocula size; temperature 250 C for five days with carboxylmethylcellulose (CMC as control. Optimization experiments were conducted by varying fermentation parameters. Results of physico-chemical analysis revealed carbohydrate 65.9%; sugars 22.60%; protein 5.38%; fibre 3.48%; fat 4.0% ash 4.02% and moisture 8.13%. Itaconic acid yield of 67.67+1.20 mg mL-1 and 70.67+2.60 mg mL-1 produced by A. niger and A. terreus from SPP respectively. The CMC yielded 3.00 +0.6 mg mL-1. Results of the optimization experiments showed higher yields of itaconic acid by A. niger and A. terreus to 112.67+5.20 mg mL-1 and 115.67+5.30 mg mL-1 from SPP respectively at pH 4.0; 10% substrate concentration; 5 mL inocula size on Day-5 of the fermentation. This represented an increase in product yield by both organisms and supports the potential use of this waste for the industrial production of itaconic acid.
Aspergillus niger produces a wide variety of carbohydrate hydrolytic enzymes which have potential applications in the baking, starch, textile, food and feed industries. The goal of this thesis is to unravel the molecular mechanisms of starch and inulin modifying network of A. niger, in order to impr
More than a century ago, in 1889, A. Fernbach presented a detailed report about the invertase of Aspergillus niger in the third edition of “Annales De L'institut Pasteur”. Since then, many of the enzymes secreted by A. niger have found a broad range of applications, and today they are produced on an
Wadman, Mayken W; de Vries, Ronald P; Kalkhove, Stefanie I C; Veldink, Gerrit A; Vliegenthart, Johannes F G
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 dio
Pel, Herman J.; de Winde, Johannes H.; Archer, David B.
The filamentous fungus Aspergillus niger is widely exploited by the fermentation industry for the production of enzymes and organic acids, particularly citric acid. We sequenced the 33.9-megabase genome of A. niger CBS 513.88, the ancestor of currently used enzyme production strains. A high level...
Gruben, B.S.; Zhou, M.; Wiebenga, A.; Ballering, J.; Overkamp, K.M.; Punt, P.J.; Vries, R.P. de
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 g
Jørgensen, Thomas R.; Park, Joohae; Arentshorst, Mark
A characteristic hallmark of Aspergillus niger is the formation of black conidiospores. We have identified four loci involved in spore pigmentation of A. niger by using a combined genomic and classical complementation approach. First, we characterized a newly isolated color mutant, colA, which la...
Yuan, X.L.; Goosen, C.; Kools, H.J.; Maarel, van der M.J.; Hondel, van den C.A.M.J.J.; Dijkhuizen, L.; Ram, A.F.
As a soil fungus, Aspergillus niger can metabolize a wide variety of carbon sources, employing sets of enzymes able to degrade plant-derived polysaccharides. In this study the genome sequence of A. niger strain CBS 513.88 was surveyed, to analyse the gene/enzyme network involved in utilization of th
Fierobe, H P; Mirgorodskaya, E; McGuire, K A; Roepstorff, P; Svensson, B; Clarke, A J
Glucoamylase catalyzes the hydrolysis of glucosidic bonds with inversion of the anomeric configuration. Site-directed mutagenesis and three-dimensional structure determination of the glucoamylase from Aspergillus awamori previously identified Glu179 and Glu400 as the general acid and base catalyst, respectively. The average distance between the two carboxyl groups was measured to be 9.2 A, which is typical for inverting glycosyl hydrolases. In the present study, this distance was increased by replacing the catalytic base Glu400 with cysteine which was then oxidized to cysteinesulfinic acid. Initially, this oxidation occurred during attempts to carboxyalkylate the Cys400 residue with iodoacetic acid, 3-iodopropionic acid, or 4-bromobutyric acid. However, endoproteinase Lys-C digestion of modified glucoamylase followed by high-pressure liquid chromatography in combination with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry on purified peptide fragments demonstrated that all enzyme derivatives contained the cysteinesulfinic acid oxidation product of Cys400. Subsequently, it was demonstrated that treatment of Glu400-->Cys glucoamylase with potassium iodide in the presence of bromine resulted in complete conversion to the cysteinesulfinic acid product. As expected, the catalytic base mutant Glu400-->Cys glucoamylase had very low activity, i.e., 0.2% compared to wild-type. The oxidation of Cys400 to cysteinesulfinic acid, however, restored activity (kcat) on alpha-1,4-linked substrates to levels up to 160% of the wild-type glucoamylase which corresponded to approximately a 700-fold increase in the kcat of the Glu400-->Cys mutant glucoamylase. Whereas Glu400-->Cys glucoamylase was much less thermostable and more sensitive to guanidinium chloride than the wild-type enzyme, the oxidation to cysteinesulfinic acid was accompanied by partial recovery of the stability.
Full Text Available Solid state fermentation holds tremendous potentials for the production of the enzyme amylase by Aspergillus niger. Different solid substrates like rice bran, wheat bran, black gram bran, coconut oil cake, gingely oil cake and groundnut oil cake are rich in starch. These agro industrial residues are cheap raw materials for amylase production. Aspergillus niger BAN3E was identified to be the best producer of amylase. When A. niger BAN3E was incubated for 6 days at 37°C it showed high yield of amylase in groundnut oil cake substratein solid state fermentation. Sucrose and nitrogen improved the yield in the same medium.
Tamayo Ramos, J.A.; Berkel, van W.J.H.; Graaff, de L.H.
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-li
Gruben, B.S.; Zhou, M.; de Vries, R.P.
Galactose catabolism in Aspergillus nidulans is regulated by at least two regulators, GalR and GalX. In Aspergillus niger only GalX is present, and its role in d-galactose catabolism in this fungus was investigated. Phenotypic and gene expression analysis of a wild type and a galX disruptant reveale
Andersen, Mikael R.; Salazar, Margarita; Schaap, Peter; van de Vondervoort, Peter; Culley, David E.; Thykaer, Jette; Frisvad, Jens C.; Nielsen, Kristian F.; Albang, Richard; Albermann, Kaj; Berka, Randy; Braus, Gerhard; Braus-Stromeyer, Susanna A.; Corrochano, Luis; Dai, Ziyu; van Dijck, Piet; Hofmann, Gerald; Lasure, Linda L.; Magnuson, Jon K.; Menke, Hildegard; Meijer, Martin; Meijer, Susan; Nielsen, Jakob B.; Nielsen, Michael L.; van Ooyen, Albert; Pel, Herman J.; Poulsen, Lars; Samson, Rob; Stam, Hein; Tsang, Adrian; van den Brink, Johannes M.; ATkins, Alex; Aerts, Andrea; Shapiro, Harris; Pangilinan, Jasmyn; Salamov, Asaf; Lou, Yigong; Lindquist, Erika; Lucas, Susan; Grimwood, Jane; Grigoriev, Igor V.; Kubicek, Christian P.; Martinez, Diego; van Peij, Noel; Roubos, Johannes A.; Nielsen, Jens B.; Baker, Scott E.
The filamentous fungus Aspergillus niger exhibits great diversity in its phenotype. It is found globally, both as marine and terrestrial strains, produces both organic acids and hydrolytic enzymes in high amounts, and some isolates exhibit pathogenicity. Although the genome of an industrial enzyme-producing A. niger strain (CBS 513.88) has already been sequenced, the versatility and diversity of this species compels additional exploration. We therefore undertook whole genome sequencing of the acidogenic A. niger wild type strain (ATCC 1015), and produced a genome sequence of very high quality. Only 15 gaps are present in the sequence and half the telomeric regions have been elucidated. Moreover, sequence information from ATCC 1015 was utilized to improve the genome sequence of CBS 513.88. Chromosome-level comparisons uncovered several genome rearrangements, deletions, a clear case of strain-specific horizontal gene transfer, and identification of 0.8 megabase of novel sequence. Single nucleotide polymorphisms per kilobase (SNPs/kb) between the two strains were found to be exceptionally high (average: 7.8, maximum: 160 SNPs/kb). High variation within the species was confirmed with exo-metabolite profiling and phylogenetics. Detailed lists of alleles were generated, and genotypic differences were observed to accumulate in metabolic pathways essential to acid production and protein synthesis. A transcriptome analysis revealed up-regulation of the electron transport chain, specifically the alternative oxidative pathway in ATCC 1015, while CBS 513.88 showed significant up regulation of genes associated with biosynthesis of amino acids that are abundant in glucoamylase A, tRNA-synthases and protein transporters.
Frisvad, Jens Christian; Petersen, Lene Maj; Lyhne, Ellen Kirstine
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...
Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan
Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.
Krauze, J.; Wawrzyniak, B.
Glucoamylase from Aspergillus niger was immobilized by entrapping in glutaraldehyde crosslinked gelatin. Preparations were prepared in the form of beads and thin layers on activated glass, polyester and aluminium foils. Immobilization did not cause changes of pH and temperature optimum. However, it increased thermal stability additionally stabilized by the presence of a substrate. The most stable preparations acted without change in activity for 34 days at a temperature of 50/sup 0/C. Obtained preparations hydrolyzed ..cap alpha..-amylase liquefied starch to a DE value of about 97%. The preparations of glucoamylase immobilized in a thin layer of gelatin on the polyester and aluminium foil were used in a thin layer-flow reactor for hydrolysis of 10% starch solution.
Pisani, Cristina; Nguyen, Trang Thoaivan; Gubler, Walter Douglas
Sour rot, is a pre-harvest disease that affects many grape varieties. Sour rot symptoms include initial berry cracking and breakdown of berry tissue. This is a disease complex with many filamentous fungi and bacteria involved, but is usually initiated by Aspergillus niger or Aspergillus carbonarius. Usually, by the time one sees the rot there are many other organisms involved and it is difficult to attribute the disease to one species. In this study two species of Aspergillus were shown to produce a previously unknown fruiting structure in infected berries. The nodulous morphology, bearing conidia, suggests them to be an 'everted polymorphic stroma'. This structure forms freely inside the berry pulp and assumes multiple shapes and sizes, sometimes sclerotium-like in form. It is composed of a mass of vegetative hyphae with or without tissue of the host containing spores or fruiting bodies bearing spores. Artificially inoculated berries placed in soil in winter showed the possible overwintering function of the fruiting body. Inoculated berry clusters on standing vines produced fruiting structures within 21 d post inoculation when wounds were made at veraison or after (July-September). Histological studies confirmed that the fruiting structure was indeed fungal tissue.
Arotupin Daniel Juwon
Full Text Available Aims: The research was carried out to study the purification, characterization and application of polygalacturonase fromAspergillus niger CSTRF.Methodology and Results: The polygalacturonase (PG from the fungus was purified by ammonium sulphate precipitation and dialysed. The resulting fraction of the enzyme was further separated by molecular exclusion and ion exchange chromatography. The enzyme was purified 28.19 fold with a yield of approximately 69 % following purificationwith SP C-50. It has a relative molecular weight of 79,430 daltons and markedly influenced by temperature, pH and substrate concentrations of reactions with optimum activity at 35 °C, pH 4.0 and 8 mg/mL respectively. The PG was heat stable over a broad range of temperatures. Line weaver-Burk plot for the apparent hydrolysis of pectin showed approximately Km value of 2.7 mg/mL. The activity of the enzyme was enhanced by Na+, Ca2+, Mg2+ and Zn2+, while EDTA, PbCl2, HgCl2 and IAA were inhibitory. The ability of the purified enzyme to clarify fruit juice was also investigated.Conclusion, significance and impact of the study: This study revealed that polygalacturonase possesses properties for clarification of fruit juice and by extension bioprocessing applications.
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
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
Wang, Lu; Zhang, Jianhua; Cao, Zhanglei; Wang, Yajun; Gao, Qiang; Zhang, Jian; Wang, Depei
Background The spore germination rate and growth characteristics were compared between the citric acid high-yield strain Aspergillus niger CGMCC 5751 and A. niger ATCC 1015 in media containing antimycin A or DNP. We inferred that differences in citric acid yield might be due to differences in energy metabolism between these strains. To explore the impact of energy metabolism on citric acid production, the changes in intracellular ATP, NADH and NADH/NAD+ were measured at various fermentation s...
Vermeulen, E; Maertens, J; Meersseman, P; Saegeman, V; Dupont, L; Lagrou, K
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.
Zhao, Xinying; Hu, Yihua; Gu, Youlin; Li, Le
Microorganism aggregated particle swarm, which is quite an important composition of complex media environment, can be developed as a new kind of infrared functional materials. Current researches mainly focus on the optical properties of single microorganism particle. As for the swarm, especially the microorganism aggregated particle swarm, a more accurate simulation model should be proposed to calculate its extinction effect. At the same time, certain parameters deserve to be discussed, which helps to better develop the microorganism aggregated particle swarm as a new kind of infrared functional materials. In this paper, take Aspergillus Niger spore as an example. On the one hand, a new calculation model is established. Firstly, the cluster-cluster aggregation (CCA) model is used to simulate the structure of Aspergillus Niger spore aggregated particle. Secondly, the single scattering extinction parameters for Aspergillus Niger spore aggregated particle are calculated by using the discrete dipole approximation (DDA) method. Thirdly, the transmittance of Aspergillus Niger spore aggregated particle swarm is simulated by using Monte Carlo method. On the other hand, based on the model proposed above, what influences can wavelength causes has been studied, including the spectral distribution of scattering intensity of Aspergillus Niger spore aggregated particle and the infrared spectral transmittance of the aggregated particle swarm within the range of 8～14μm incident infrared wavelengths. Numerical results indicate that the scattering intensity of Aspergillus Niger spore aggregated particle reduces with the increase of incident wavelengths at each scattering angle. Scattering energy mainly concentrates on the scattering angle between 0～40°, forward scattering has an obvious effect. In addition, the infrared transmittance of Aspergillus Niger spore aggregated particle swarm goes up with the increase of incident wavelengths. However, some turning points of the trend
Holm, Dorte Koefoed; Petersen, Lene Maj; Klitgaard, Andreas
We have elucidated the mode of biosynthesis of the meroterpenoid compound Yanuthone D in Aspergillus niger. We have successfully deleted all cluster genes, and identified a number of intermediates. Structures of the intermediates were solved using a combined approach comprising classical 1D- and 2D......-NMR and tandem mass spectrometry (MS/MS). In this study we have confirmed that Yanuthone D is of meroterpenoid origin, and we have identified an unexpected precursor, which has not before been reported for Aspergillus niger....
José Miguel P Ferreira de Oliveira
Full Text Available Fungi utilize polysaccharide substrates through extracellular digestion catalyzed by secreted enzymes. Thus far, protein secretion by the filamentous fungus Aspergillus niger has mainly been studied at the level of individual proteins and by genome and transcriptome analyses. To extend these studies, a complementary proteomics approach was applied with the aim to investigate the changes in secretome and microsomal protein composition resulting from a shift to a high level secretion condition. During growth of A. niger on D-sorbitol, small amounts of D-maltose or D-xylose were used as inducers of the extracellular amylolytic and xylanolytic enzymes. Upon induction, protein compositions in the extracellular broth as well as in enriched secretory organelle (microsomal fractions were analyzed using a shotgun proteomics approach. In total 102 secreted proteins and 1,126 microsomal proteins were identified in this study. Induction by D-maltose or D-xylose resulted in the increase in specific extracellular enzymes, such as glucoamylase A on D-maltose and β-xylosidase D on D-xylose, as well as of microsomal proteins. This reflects the differential expression of selected genes coding for dedicated extracellular enzymes. As expected, the addition of extra D-sorbitol had no effect on the expression of carbohydrate-active enzymes, compared to addition of D-xylose or D-maltose. Furthermore, D-maltose induction caused an increase in microsomal proteins related to translation (e.g., Rpl15 and vesicular transport (e.g., the endosomal-cargo receptor Erv14. Millimolar amounts of the inducers D-maltose and D-xylose are sufficient to cause a direct response in specific protein expression levels. Also, after induction by D-maltose or D-xylose, the induced enzymes were found in microsomes and extracellular. In agreement with our previous findings for D-xylose induction, D-maltose induction leads to recruitment of proteins involved in proteasome-mediated degradation.
Kumar, Sunil; Saragadam, Tejaswani; Punekar, Narayan S
Agmatine, a significant polyamine in bacteria and plants, mostly arises from the decarboxylation of arginine. The functional importance of agmatine in fungi is poorly understood. The metabolism of agmatine and related guanidinium group-containing compounds in Aspergillus niger was explored through growth, metabolite, and enzyme studies. The fungus was able to metabolize and grow on l-arginine, agmatine, or 4-guanidinobutyrate as the sole nitrogen source. Whereas arginase defined the only route for arginine catabolism, biochemical and bioinformatics approaches suggested the absence of arginine decarboxylase in A. niger. Efficient utilization by the parent strain and also by its arginase knockout implied an arginase-independent catabolic route for agmatine. Urea and 4-guanidinobutyrate were detected in the spent medium during growth on agmatine. The agmatine-grown A. niger mycelia contained significant levels of amine oxidase, 4-guanidinobutyraldehyde dehydrogenase, 4-guanidinobutyrase (GBase), and succinic semialdehyde dehydrogenase, but no agmatinase activity was detected. Taken together, the results support a novel route for agmatine utilization in A. niger. The catabolism of agmatine by way of 4-guanidinobutyrate to 4-aminobutyrate into the Krebs cycle is the first report of such a pathway in any organism. A. niger GBase peptide fragments were identified by tandem mass spectrometry analysis. The corresponding open reading frame from the A. niger NCIM 565 genome was located and cloned. Subsequent expression of GBase in both Escherichia coli and A. niger along with its disruption in A. niger functionally defined the GBase locus (gbu) in the A. niger genome.
李廷生; 王平诸; 鲍宇茹
采用紫外线和微波处理黑曲霉(Aspergillus niger) 孢子,获得1株比出发菌株果胶酶产生能力提高2倍的突变株3502;在用正交试验优选而得的最佳固体发酵条件下,酶活力达2 644 u/g.
The aim of this Thesis was to study mechanism involved in zonal secretion in colonies of A. niger with emphasis on sporulation inhibited secretion. These mechanisms may be targets to improve A. nigeras a cell factory. I focused in particular on A. niger homologues of fluG and veA that are known spor
Sloothaak, J.; Odoni, D.I.; Graaff, de L.H.; Martins dos Santos, V.A.P.; Schaap, P.J.; Tamayo Ramos, J.A.
BACKGROUND: The development of biological processes that replace the existing petrochemical-based industry is one of the biggest challenges in biotechnology. Aspergillus niger is one of the main industrial producers of lignocellulolytic enzymes, which are used in the conversion of lignocellulosic fe
Brink, J.M. van den; Punt, P.J.; Gorcom, R.F.M. van; Hondel, C.A.M.J.J. van den
Cytochrome P450 enzyme systems are found throughout nature and are involved in many different, often complex, bioconversions. In the endoplasmic reticulum of the filamentous fungus Aspergillus niger a cytochrome P450 enzyme system is present that is capable of the para-hydroxylation of benzoate. The
An Aspergillus niger mutant strain, VTT-D-80144, with an improvement of three- to fourfold in the production of extracellular beta-galactosidase was isolated after mutagenesis. The production of beta-galactosidase by this mutant was unaffected by fermentor size, and the enzyme was also suitable for immobilization.
Braaksma, M.; Smilde, A.K.; Werf, M.J. van der; Punt, P.J.
Proteolytic degradation by host proteases is one of the key issues in the application of filamentous fungi for non-fungal protein production. In this study the influence of several environmental factors on the production of extracellular proteases of Aspergillus niger was investigated systematically
Poulsen, B.R.; Nohr, J.; Douthwaite, S.; Hansen, L.V.; Iversen, J.J.L.; Visser, J.; Ruijter, G.J.G.
Many biosynthetic reactions and bioconversions are limited by low availability of NADPH. With the purpose of increasing the NADPH concentration and/or the flux through the pentose phosphate pathway in Aspergillus niger, the genes encoding glucose 6-phosphate dehydrogenase (gsdA), 6-phosphogluconate
Lameiras, F.; Heijnen, J.J.; Van Gulik, W.M.
In view of the high citric acid production capacity of Aspergillus niger, it should be well suited as a cell factory for the production of other relevant acids as succinic, fumaric, itaconic and malic. Quantitative metabolomics is an important omics tool in a synthetic biology approach to develop A.
Noonim, P.; Mahakarnchanaku, W.; Nielsen, Kristian Fog
by black Aspergilli. No Fusarium species known to produce fumonisin were detected, but black Aspergilli had high incidences on both Arabica and Robusta Thai coffee beans. Liquid chromatography (LC) with high-resolution mass spectrometric (HRMS) detection showed that 67% of Aspergillus niger isolates from...
WU Zu-Jian; OUYANG Ming-An; SU Ren-Kuan; KUO Yueh-Hsiung
Two new cerebrosides, asperiamide B (1) and C (2), and two known aflatoxins, averufin and nidurufin, have been isolated from a Quanzhou marine fungus Aspergillus niger (MF-16), and the structures were elucidated by spectroscopic data and chemical means. Among the compounds 5 and 6 showed moderate activities in inhibiting multiplication of the Tobacco Mosaic Virus (TMV).
Diano, Audrey; Bekker-Jensen, S; Dynesen, Jens Østergaard
Polyol production has been studied in Aspergillus niger under different conditions. Fermentations have been run using high concentration of glucose or xylose as carbon source and ammonium or nitrate as nitrogen source. The growth of biomass, as freely dispersed hyphae, led to an increase of medium...
Poulsen, Lars; Andersen, Mikael Rørdam; Lantz, Anna Eliasson
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...
The fungus Fusarium oxysporum causes wilt diseases of plants and produces a potent phytotoxin fusaric acid (FA) which is also toxic to many microorganisms. An Aspergillus strain with high tolerance to FA was isolated from soil. HPLC analysis of culture filtrates from A. niger grown with the addition...
This study was to compare three phytase activity assays and kinetics of Aspergillus niger PhyA and Escherichia coli AppA2 phytases expressed in Pichia pastoris at the observed stomach pH of 3.5. In Experiment 1, equivalent phytase activities in the crude preparations of PhyA and AppA2 were tested ...
Poulsen, Lars; Bruno, K.S.; Thykær, Jette
). In the present study the effect of modulation of transcription factors in Aspergillus niger, which is an industrially important micro-organism used in various processes including organic acid and enzyme production, was investigated. The strategy described in this work focuses on regulation connected to p...
Aspergillus niger and A. awamori strains isolated from grapes cultivated in Mediterranean basin were examined for fumonisin B2 (FB2) production and presence/absence of sequences within the fumonisin biosynthetic gene (fum) cluster. Presence of 13 regions in the fum cluster was evaluated by PCR assay...
Full Text Available 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.
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...
Zeuner, Birgitte; Riisager, Anders; Meyer, Anne S.
in solvents that favour synthesis over hydrolysis, i.e. systems with low water content such as organic solvents or ionic liquids (ILs). The esterification of sinapic acid with glycerol catalysed by FAE A from Aspergillus niger (AnFaeA) in a series of ILs containing 15% (v/v) buffer showed that An...
Schröter, K.-H.; Arkema, A.; Kester, H.C.M.; Visser, J.; Dijkstra, B.W.
The endo-polygalacturonase II from Aspergillus niger has been crystallized from an ammonium sulfate solution by the hanging drop method. The crystals belong to the monoclinic space group P2(1), with cell dimensions a = 60.6 Angstrom, b = 152.6 Angstrom, c = 74.0 Angstrom and beta = 91.2 degrees with
Goosen, C.; Maarel, M.J. E.C. van der; Dijkhuizen, L.
The purified exo-inulinase enzyme of Aspergillus niger N402 (AngInuE; heterologously expressed in Escherichia coli) displayed a sucrose:inulin (S/I) hydrolysis ratio of 2.3, characteristic for a typical exo-inulinase. The enzyme also had significant transfructosylating activity with increasing sucro
Damak, Naourez; Abdeljalil, Salma; Taeib, Noomen Hadj; Gargouri, Ali
The rhg gene encoding a rhamnogalacturonase was isolated from the novel strain A1 of Aspergillus niger. It consists of an ORF of 1.505 kb encoding a putative protein of 446 amino acids with a predicted molecular mass of 47 kDa, belonging to the family 28 of glycosyl hydrolases. The nature and position of amino acids comprising the active site as well as the three-dimensional structure were well conserved between the A. niger CTM10548 and fungal rhamnogalacturonases. The coding region of the rhg gene is interrupted by three short introns of 56 (introns 1 and 3) and 52 (intron 2) bp in length. The comparison of the peptide sequence with A. niger rhg sequences revealed that the A1 rhg should be an endo-rhamnogalacturonases, more homologous to rhg A than rhg B A. niger known enzymes. The comparison of rhg nucleotide sequence from A. niger A1 with rhg A from A. niger shows several base changes. Most of these changes (59 %) are located at the third base of codons suggesting maintaining the same enzyme function. We used the rhamnogalacturonase A from Aspergillus aculeatus as a template to build a structural model of rhg A1 that adopted a right-handed parallel β-helix.
Implicações do fungo Aspergillus niger var. niger sobre o crescimento de isolados de Aspergillus da seção Circumdati e produção de Ocratoxina a Implications of Aspergillus niger var. niger's mold, fungi upon growing Aspergillus's isolate of section Circumdati and Ochratoxin a
Patrícia Prado Nasser
Full Text Available Buscando esclarecimento a respeito da inibição ou estímulo na produção de ocratoxina A (OTA e no crescimento dos fungos ocratoxigênicos por fungos que também ocorrem naturalmente associados aos grãos de café, com o presente estudo avaliou-se o efeito inibitório do fungo Aspergillus niger var. niger EcoCentro 1181-01(“inibidor” e seu filtrado, sobre o crescimento de isolados de Aspergillus da seção Circumdati e produção de ocratoxina A. O isolado atoxigênico do fungo “inibidor”, selecionado como possível antagonista para espécies toxigênicas do gênero Aspergillus da seção Circumdati, apresentou um efeito positivo inibidor sobre os índices de velocidade de crescimento micelial em relação aos demais isolados testados. A ação antagonista do fungo “inibidor” associado a grãos de café pode ser um dos fatores responsáveis pelos níveis reduzidos de OTA detectados nas amostras analisadas.The present study evaluated the inhibitory effect of the fungus Aspergillus niger var. niger EcoCentro 1181T-01 (inhibitor and its filtrate on the growth of an Aspergillus isolate of the section Circumdati and ochratoxin A (OTA production. An atoxigenic isolate of the inhibitor fungus screened as possible antagonist for toxigenic species of the genus Aspergillus, section Circumdati,showed a positive inhibitory effect upon mycelial growth velocity indices comparing with the isolates tested. The antagonistic action of the inhibitor fungus associated with coffee beans may be one of the factors responsible for the reduced levels of OTA detected in the samples analyzed.
Meijer, Susan Lisette; Nielsen, Michael Lynge; Olsson, Lisbeth
With the availability of the genome sequence of the filamentous fungus Aspergillus niger, the use of targeted genetic modifications has become feasible. This, together with the fact that A. niger is well established industrially, makes this fungus an attractive micro-organism for creating a cell...... factory platform for production of chemicals. Using molecular biology techniques, this study focused on metabolic engineering of A. niger to manipulate its organic acid production in the direction of succinic acid. The gene target for complete gene deletion was cytosolic ATP: citrate lyase (acl), which...... the acl gene. Additionally, the total amount of organic acids produced in the deletion strain was significantly increased. Genome-scale stoichiometric metabolic model predictions can be used for identifying gene targets. Deletion of the acl led to increased succinic acid production by A. niger....
Buren, Emiel B J Ten; Karrenbelt, Michiel A P; Lingemann, Marit; Chordia, Shreyans; Deng, Ying; Hu, JingJing; Verest, Johanna M; Wu, Vincen; Gonzalez, Teresita J Bello; Heck, Ruben G A van; Odoni, Dorett I; Schonewille, Tom; Straat, Laura van der; Graaff, Leo H de; Passel, Mark W J van
Aspergillus niger is a filamentous fungus that is extensively used in industrial fermentations for protein expression and the production of organic acids. Inherent biosynthetic capabilities, such as the capacity to secrete these biomolecules in high amounts, make A. niger an attractive production host. Although A. niger is renowned for this ability, the knowledge of the molecular components that underlie its production capacity, intercellular trafficking processes and secretion mechanisms is far from complete. Here, we introduce a standardized set of tools, consisting of an N-terminal GFP-actin fusion and codon optimized eforRed chromoprotein. Expression of the GFP-actin construct facilitates visualization of the actin filaments of the cytoskeleton, whereas expression of the chromoprotein construct results in a clearly distinguishable red phenotype. These experimentally validated constructs constitute the first set of standardized A. niger biomarkers, which can be used to study morphology, intercellular trafficking, and secretion phenomena.
Nielsen, Kristian Fog; Mogensen, Jesper Mølgaard; Johansen, Maria
Filamentous fungi in the Aspergillus section Nigri (the black aspergilli) represent some of the most widespread food and feed contaminants known but they are also some of the most important workhorses used by the biotechnological industry. The Nigri section consists of six commonly found species...... (excluding A. aculeatus and its close relatives) from which currently 145 different secondary metabolites have been isolated and/or detected. From a human and animal safety point of view, the mycotoxins ochratoxin A (from A. carbonarius and less frequently A. niger) and fumonisin B2 (from A. niger...... since it is consistently produced by A. tubingensis (177 of 177 strains tested) and A. acidus (47 of 47 strains tested) but never by A. niger (140 strains tested). Naptho-γ-pyrones are the compounds produced in the highest quantities and are produced by all six common species in the group (A. niger 134...
Shivanna, Gunashree B; Venkateswaran, Govindarajulu
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.
Zwane, Eunice N; Rose, Shaunita H; van Zyl, Willem H; Rumbold, Karl; Viljoen-Bloom, Marinda
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.
Wei Zhang; Beibei Xue; Mengmeng Li; Yang Mu; Zhihui Chen; Jianping Li; Anshan Shan
Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis ...
ZHU; Xingguo; WANG; H.; M.; QIU; Runxiang; LIU; Li; DONG; Zh
EMSA and footprinting analyses have revealed that the 489-414 bp and the 390-345 bp (designated DC and PC respectively) upstream of the Aspergillus niger T21 glaA gene were bound by one protein factor in the A. niger T21 whole cell extract. Both DC and PC contained CCAAT pentanucleotides. The functions of DC and PC in regulation of expression of glucoamylase (GLA) were studied. CCAAT pentanucleotides were replaced with CGTAA and the mutated DNA fragments DCm and PCm lost the binding activities of protein factors in vitro. In vivo when either DC or PC was mutated or the relative orientations between them were changed on the PglaA, the transcriptional activity of PglaA decreased to a basal level. Introduction of multi-copies of DC into the original site at the PglaA in A. niger T21 decreased the expression of endogenous GLA expression and the exogenous reporter E. coli uidA gene introduced under the PglaA promoter, while having no effect on the uidA gene under the control of PgpdA. EMSA revealed that the levels of the specific DNA-binding protein factors in the transformants maintained the same meaning that introduction of multi-copies of DC caused the titration effect. AnghapC gene was cloned from A. niger T21 cDNA and introduced into the DC multi-copied strains. The expression of AnghapC improved the expression of the endogenous GLA and the exogenous gene controlled by PglaA. These results showed that both the CCAAT pentanucleotides were necessary for DC and PC binding to the protein factors, and the simultaneous binding of DC and PC to the protein was necessary for promoting the transcriptional activity of PglaA. AngHapC was the specific positive trans-acting protein factor binding to DC.
Parjo, U. K.; Sunar, N. M.; Leman, A. M.; Gani, P.; Embong, Z.; Tajudin, S. A. A.
The aim of this study was to evaluate the Aspergillus niger (A. niger) growth on substrates after incorporates with different compounds of antifungals which is normally used in food industry. The antifungals named as potassium sorbate (PS), calcium benzoate (CB) and zinc salicylate (ZS) were applied on concrete substrate covered with different wall finishing such as acrylic paint (AP), glycerol based paint (GBP), thin wallpaper (THIN) and thick wallpaper (THICK). The concrete substrate were inoculated with spore suspension, incubated at selected temperature (30oC) and relative humidity (90%)in plant growth chamber. The observations were done from the Day 3 until Day 27. The results showed that the growth of the A. niger for concrete treated by PS for AP, GBP, THIN, and THICK were 64%, 32%, 11% and 100%, respectively. Meanwhile for CB, the growth of A. niger on AP, GBP, THIN, and THICK were 100%, 12%, 41%, and 13%, respectively. Similarly, treated concrete by ZS revealed that the growth of A. niger on the same substrate cover were 33%, 47%, 40%, and 39%, respectively. The results obtained in this study provide a valuable knowledge on the abilities of antifungals to remediate A. niger that inoculated on the concrete substrate. Consequently, this study proved that the PS covering with THIN more efficiency compares CB and ZS to prevent A. niger growth.
Wang, Fengfeng; Dijksterhuis, Jan; Wyatt, Timon; Wösten, Han A B; Bleichrodt, Robert-Jan
Aspergillus species are highly abundant fungi worldwide. Their conidia are among the most dominant fungal spores in the air. Conidia are formed in chains on the vesicle of the asexual reproductive structure called the conidiophore. Here, it is shown that the velvet protein VeA of Aspergillus niger maximizes the diameter of the vesicle and the spore chain length. The length and width of the conidiophore stalk and vesicle were reduced nearly twofold in a ΔveA strain. The latter implies a fourfold reduced surface area to develop chains of spores. Over and above this, the conidial chain length was approximately fivefold reduced. The calculated 20-fold reduction in formation of conidia by ΔveA fits the 8- to 17-fold decrease in counted spore numbers. Notably, morphology of the ΔveA conidiophores of A. niger was very similar to that of wild-type Aspergillus sydowii. This suggests that VeA is key in conidiophore architecture diversity in the fungal kingdom. The finding that biomass formation of the A. niger ΔveA strain was reduced twofold shows that VeA not only impacts dispersion capacity but also colonization capacity of A. niger.
Jørgensen, T.R.; Nielsen, K.F.; Arentshorst, M.; Park, J.; Van den Hondel, C.A.; Frisvad, J.C.; Ram, A.F.
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 revea
Jørgensen, Thomas R.; Nielsen, Kristian Fog; Arentshorst, Mark
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...
Prathumpai, Wai; Flitter, S.J.; Mcintyre, Mhairi
Two recombinant strains of Aspergillus niger (NW 297-14 and NW297-24) producing a heterologous lipase from Thermomyces lanuginosus were constructed. The heterologous lipase was expressed using the TAKA amylase promoter from Aspergillus oryzae. The production kinetics of the two strains on different...... shows that it is possible to obtain high productivities of heterologous fungal enzymes in A. niger. However, SDS-PAGE analysis showed that most of the produced lipase was bound to the cell wall....
Andersen, Mikael Rørdam; Lehmann, Linda Olkjær; Nielsen, Jens
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...... efficient acidification as well as production process applicable knowledge on the transcriptional regulation of pH response in the industrially important A. niger. It has also made clear that filamentous fungi have evolved to employ several offensive strategies for out-competing rival organisms....
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
Palencia, Edwin Rene; Glenn, Anthony Elbie; Hinton, Dorothy Mae; Bacon, Charles Wilson
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.
田英华; 刘晓兰; 邓永平
Wang, Shihui; Lin, Chaoyang; Liu, Yun; Shen, Zhicheng; Jeyaseelan, Jenasia; Qin, Wensheng
Aspergillus niger is the most commonly used fungus for commercial amylase production, the increase of amylase activity will be beneficial to the amylase industry. Herein we report a high α-amylase producing (HAP) A. niger WLB42 mutated from A. niger A4 by ethyl methanesulfonate treatment. The fermentation conditions for the amylase production were optimized. The results showed that both the amylase activity and total protein content reached highest after 48-h incubation in liquid medium using...
Dave, Khyati K; Punekar, Narayan S
Different engineered organisms have been used to produce L-lactate. Poor yields of lactate at low pH and expensive downstream processing remain as bottlenecks. Aspergillus niger is a prolific citrate producer and a remarkably acid tolerant fungus. Neither a functional lactate dehydrogenase (LDH) from nor lactate production by A. niger is reported. Its genome was also investigated for the presence of a functional ldh. The endogenous A. niger citrate synthase promoter relevant to A. niger acidogenic metabolism was employed to drive constitutive expression of mouse lactate dehydrogenase (mldhA). An appraisal of different branches of the A. niger pyruvate node guided the choice of mldhA for heterologous expression. A high copy number transformant C12 strain, displaying highest LDH specific activity, was analyzed under different growth conditions. The C12 strain produced 7.7 g/l of extracellular L-lactate from 60 g/l of glucose, in non-neutralizing minimal media. Significantly, lactate and citrate accumulated under two different growth conditions. Already an established acidogenic platform, A. niger now promises to be a valuable host for lactate production.
Nitsche, Benjamin M; Burggraaf-van Welzen, Anne-Marie; Lamers, Gerda; Meyer, Vera; Ram, Arthur F J
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.
Sepúlveda, Leonardo; de la Cruz, Reynaldo; Buenrostro, José Juan; Ascacio-Valdés, Juan Alberto; Aguilera-Carbó, Antonio Francisco; Prado, Arely; Rodríguez-Herrera, Raúl; Aguilar, Cristóbal Noé
Fungal hydrolysis of ellagitannins produces hexahydroxydiphenic acid, which is considered an intermediate molecule in ellagic acid release. Ellagic acid has important and desirable beneficial health properties. The aim of this work was to identify the effect of different sources of ellagitannins on the efficiency of ellagic acid release by Aspergillus niger. Three strains of A. niger (GH1, PSH and HT4) were assessed for ellagic acid release from different polyphenol sources: cranberry, creosote bush, and pomegranate used as substrate. Polyurethane foam was used as support for solid-state culture in column reactors. Ellagitannase activity was measured for each of the treatments. Ellagic acid was quantified by high performance liquid chromatography. When pomegranate polyphenols were used, a maximum value of ellagic acid (350.21 mg/g) was reached with A. niger HT4 in solid-state culture. The highest amount of ellagitannase (5176.81 U/l) was obtained at 8h of culture when cranberry polyphenols and strain A. niger PSH were used. Results demonstrated the effect of different polyphenol sources and A. niger strains on ellagic acid release. It was observed that the best source for releasing ellagic acid was pomegranate polyphenols and A. niger HT4 strain, which has the ability to degrade these compounds for obtaining a potent bioactive molecule such as ellagic acid.
Mogensen, Jesper Mølgaard; Frisvad, Jens Christian; Thrane, Ulf
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 B2 and fumonisin B4 on grapes in the range 171−7841 μg fumonisin B2/kg and 14−1157 μg fumonisin B4/kg. Four selected strains were able to produce fumonisin B2 (5−6476 μg/kg) and fumonisin B4 (12−672 μg...
Full Text Available The cultivation procedure and the fungal strain applied for enzyme production may influence levels and profile of the proteins produced. The proteomic analysis data presented here provide critical information to compare proteins secreted by Trichoderma reesei and Aspergillus niger when cultivated through submerged and sequential fermentation processes, using steam-explosion sugarcane bagasse as inducer for enzyme production. The proteins were organized according to the families described in CAZy database as cellulases, hemicellulases, proteases/peptidases, cell-wall-protein, lipases, others (catalase, esterase, etc., glycoside hydrolases families, predicted and hypothetical proteins. Further detailed analysis of this data is provided in “Secretome analysis of Trichoderma reesei and Aspergillus niger cultivated by submerged and sequential fermentation process: enzyme production for sugarcane bagasse hydrolysis” C. Florencio, F.M. Cunha, A.C Badino, C.S. Farinas, E. Ximenes, M.R. Ladisch (2016 .
Li, Zhipeng; Ahn, Hyung Jin; Kim, Nam Yeon; Lee, Yu Na; Ji, Geun Eog
To transform ginsenosides, Korean ginseng berry (KGB) was fermented by mycotoxin non-producing Aspergillus niger and Aspergillus oryzae. Changes of ginsenoside profile and anti-proliferative activities were observed. Results showed that A. niger tended to efficiently transform protopanaxadiol (PPD) type ginsenosides such as Rb1, Rb2, Rd to compound K while A. oryzae tended to efficiently transform protopanaxatriol (PPT) type ginsenoside Re to Rh1 via Rg1. Butanol extracts of fermented KGB showed high cytotoxicity on human adenocarcinoma HT-29 cell line and hepatocellular carcinoma HepG2 cell line while that of unfermented KGB showed little. The minimum effective concentration of niger-fermented KGB was less than 2.5 µg/mL while that of oryzae-fermented KGB was about 5 µg/mL. As A. niger is more inclined to transform PPD type ginsenosides, niger-fermented KGB showed stronger anti-proliferative activity than oryzae-fermented KGB.
Jorge Alberto Vieira Costa
Full Text Available Amyloglucosidase (AMG and exo-polygalacturonase (exo-PG were simultaneously produced by two different strains of Aspergillus niger in solid-state fermentation (SSF using defatted rice-bran as substrate. The effect of Aspergillus niger strain (t0005/007-2 and/or CCT 3312, inoculum type (spore suspension or fermented bran and addition of inducers (pectin and/or starch to the culture media was studied using a 3² x 2¹ factorial experimental design. The production of AMG and exo-PG was significantly affected by fungal strain and inoculum type but inducers had no effect. The maximum yields obtained were 1310 U/g dm for AMG using a spore suspension of A. niger CCT 3312 and 50.2 U/g dm for exo-PG production, using A. niger t0005/007-2 and fermented bran as inoculum. The yields obtained represented acceptable values in comparison with data available in the literature and indicated that defatted rice-bran was a good nutrient source.As enzimas amiloglicosidase (AMG e exo-poligalacturonase (exo-PG foram produzidas simultaneamente por duas cepas de Aspergillus niger, através de fermentação em estado sólido usando farelo de arroz desengordurado como substrato. Foram avaliados os efeitos da cepa de Aspergillus niger, tipo de inóculo e adição de indutores no meio de cultura, utilizando-se um planejamento experimental fracionário 3² x 2¹. O máximo rendimento obtido foi 1310 U/g ms para a produção de AMG e 50,2 U/g ms para a exo-PG. Comparando-se estes resultados com dados da literatura pode-se dizer que os rendimentos obtidos foram aceitáveis e indicam que o farelo de arroz desengordurado é uma boa fonte de nutrientes. A produção de AMG e exo-PG foi significativamente afetada pelas variáveis cepa de A. niger e tipo de inóculo, enquanto a variável indutor não apresentou influência significativa na produção destas enzimas.
Massi, Fernanda Pelisson; Sartori, Daniele; de Souza Ferranti, Larissa; Iamanaka, Beatriz Thie; Taniwaki, Marta Hiromi; Vieira, Maria Lucia Carneiro; Fungaro, Maria Helena Pelegrinelli
Aspergillus niger "aggregate" is an informal taxonomic rank that represents a group of species from the section Nigri. Among A. niger "aggregate" species Aspergillus niger sensu stricto and its cryptic species Aspergillus welwitschiae (=Aspergillus awamori sensu Perrone) are proven as ochratoxin A and fumonisin B2 producing species. A. niger has been frequently found in tropical and subtropical foods. A. welwitschiae is a new species, which was recently dismembered from the A. niger taxon. These species are morphologically very similar and molecular data are indispensable for their identification. A total of 175 Brazilian isolates previously identified as A. niger collected from dried fruits, Brazil nuts, coffee beans, grapes, cocoa and onions were investigated in this study. Based on partial calmodulin gene sequences about one-half of our isolates were identified as A. welwitschiae. This new species was the predominant species in onions analyzed in Brazil. A. niger and A. welwitschiae differ in their ability to produce ochratoxin A and fumonisin B2. Among A. niger isolates, approximately 32% were OTA producers, but in contrast only 1% of the A. welwitschiae isolates revealed the ability to produce ochratoxin A. Regarding fumonisin B2 production, there was a higher frequency of FB2 producing isolates in A. niger (74%) compared to A. welwitschiae (34%). Because not all A. niger and A. welwitschiae strains produce ochratoxin A and fumonisin B2, in this study a multiplex PCR was developed for detecting the presence of essential genes involved in ochratoxin (polyketide synthase and radHflavin-dependent halogenase) and fumonisin (α-oxoamine synthase) biosynthesis in the genome of A. niger and A. welwitschiae isolates. The frequency of strains harboring the mycotoxin genes was markedly different between A. niger and A. welwitschiae. All OTA producing isolates of A. niger and A. welwitschiae showed in their genome the pks and radH genes, and 95.2% of the nonproducing
Full Text Available Fungal peritonitis is an uncommon condition which is associated with high morbidity and mortality in patients on continuous ambulatory peritoneal dialysis (CAPD. It is associated with several complications and many of the patients who develop this condition are unable to resume CAPD treatment and have to shift to haemodialysis. Here we report the rare occurrence of fungal peritonitis due to Aspergillus niger in a patient on CAPD.
Gera, N.; Uppaluri, R. V. S.; Sen, S.; Venkata Dasu, V.
In this paper, we demonstrate the substrate inhibition phenomena for growth kinetics of Aspergillus niger NRRL 326 grown on sucrose during glucose oxidase production. The initial set of experiments were carried out using three different substrates, viz., glucose, sucrose and raffinose of which it was observed that sucrose serves better for higher production of glucose oxidase. Experiments involving sensitivity studies conveyed that substrate inhibition became predominant when sucrose mass con...
The continuous production of extracellular heterologous beta-galactosidase by a recombinant flocculating Saccharomyces cerevisiae, expressing the lacA gene (coding for beta-galactosidase) of Aspergillus niger was investigated. A continuous operation was run in a 6.51 airlift bioreactor with a concentric draft tube using lactose as substrate. Data on the operation with semi-synthetic medium with 50 and 100 g/l initial lactose concentrations are presented. The best result for beta-galactosidase...
Prakash, Soam; Namita Soni,Namiata
Namita Soni, Soam PrakashEnvironmental and Advanced Parasitology and Vector Control Biotechnology Laboratories, Department of Zoology, Faculty of Science, Dayalbagh Educational Institute, Dayalbagh, Agra, IndiaBackground: The fungus Aspergillus niger has been selected for the synthesis of gold nanoparticles (AuNPs). The authors report the role of fungi in the synthesis of AuNPs. Additionally, the larvicidal efficacy of these AuNPs was tested using the larvae of three mosquito species: Anophel...
Towprayoon, S; Fujio, Y; Ueda, S
An inhibitory factor (IF) produced byAspergillus niger strain 19, and which inhibits the action of glucoamylase on starch, has the ability to be tightly adsorbed on to various raw starches, though the amount differs from starch to starch. Based on the hydrolysis of the IF-starch complex by glucoamylase, the inhibitions per unit IF adsorbed are similar for some varieties of starch. The effectiveness ratio of IF (% hydrolysis inhibition per % IF adsorbed on raw starch) for corn, sweet potato, waxy rice and waxy corn starches are 1.1, 1.0, 0.85 and 0.96, respectively. These results support the hypothesis that both glucoamylase and IF are adsorbed on to a common binding site on raw starch. However, the effectiveness ratio of IF for cassava and wheat starches are 0.71 and 1.65, respectively, which differ significantly from other varieties of starch.
Muhialdin, Belal J; Hassan, Zaiton; Abu Bakar, Fatimah; Algboory, Hussein L; Saari, Nazamid
The ability of Leuconostoc mesenteroides DU15 to produce antifungal peptides that inhibit growth of Aspergillus niger was evaluated under optimum growth conditions of 30 °C for 48 h. The cell-free supernatant showed inhibitory activity against A. niger. Five novel peptides were isolated with the sequences GPFPL, YVPLF, LLHGVPLP, GPFPLEMTLGPT, and TVYPFPGPL as identified by de novo sequencing using PEAKS 6 software. Peptide LLHGVPLP was the only positively charged (cationic peptides) and peptide GPFPLEMTLGPT negatively charged (anionic), whereas the rest are neutral. The identified peptides had high hydrophobicity ratio and low molecular weights with amino acids sequences ranging from 5 to 12 residues. The mode of action of these peptides is observed under the scanning electron microscope and is due to cell lysis of fungi. This work reveals the potential of peptides from L. mesenteroides DU15 as natural antifungal preservatives in inhibiting the growth of A. niger that is implicated to the spoilage during storage.
Zeni, Jamile; Pili, Jonaina; Cence, Karine; Toniazzo, Geciane; Treichel, Helen; Valduga, Eunice
The aim of this research was the partial characterization of polygalacturonase (PG) extracts produced by a newly isolated Penicillium brasilianum and Aspergillus niger in submerged fermentation. The partial characterization of the crude enzymatic extracts showed optimum activity at pH 5.5 and 37 °C for both extracts. The results of temperature stability showed that PG from both microorganisms were more stable at 55 °C. However, the enzyme obtained by P. brasilianum presents a half-life time (t 1/2 = 693.10 h), about one order of magnitude higher than those observed in for A. niger at 55 °C. In terms of pH stability, the PG produced by P. brasilianum presented higher stability at pH 4.0 and 5.0, while the PG from A. niger showed higher stability at pH 5.0.
Tamayo-Ramos Juan Antonio
Full Text Available Abstract 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.
Hayer, Kimran; Stratford, Malcolm; Archer, David B
Conidial germination is fundamentally important to the growth and dissemination of most fungi. It has been previously shown (K. Hayer, M. Stratford, and D. B. Archer, Appl. Environ. Microbiol. 79:6924-6931, 2013, http://dx.doi.org/10.1128/AEM.02061-13), using sugar analogs, that germination is a 2-stage process involving triggering of germination and then nutrient uptake for hyphal outgrowth. In the present study, we tested this 2-stage germination process using a series of nitrogen-containing compounds for the ability to trigger the breaking of dormancy of Aspergillus niger conidia and then to support the formation of hyphae by acting as nitrogen sources. Triggering and germination were also compared between A. niger and Aspergillus nidulans using 2-deoxy-D-glucose (trigger), D-galactose (nontrigger in A. niger but trigger in A. nidulans), and an N source (required in A. niger but not in A. nidulans). Although most of the nitrogen compounds studied served as nitrogen sources for growth, only some nitrogen compounds could trigger germination of A. niger conidia, and all were related to L-amino acids. Using L-amino acid analogs without either the amine or the carboxylic acid group revealed that both the amine and carboxylic acid groups were essential for an L-amino acid to serve as a trigger molecule. Generally, conidia were able to sense and recognize nitrogen compounds that fitted into a specific size range. There was no evidence of uptake of either triggering or nontriggering compounds over the first 90 min of A. niger conidial germination, suggesting that the germination trigger sensors are not located within the spore.
Muhammad Anjum Zia
Full Text Available This work aimed to study the production and purification of glucose oxidase by Aspergillus niger and Penicillium notatum using corn steep liquor as the substrate and evaluate its antimicrobial activity for use in pharmaceutical and food industries. The enzyme was purified by ammonium sulfate precipitation (60-85%, DEAE-cellulose ion exchange and Sephadex G-200 size exclusion chromatography. The crude enzyme extracts of A. niger and P. notatum showed 2.32 and 5.53 U mg-1 specific activities, respectively, which after desalting was 15.52 and 12.05 U mg-1, and after ion exchange and gel filtration chromatography was 29.09 - 62 and 25.72 - 59.37 U mg-1 for A. niger and P. notatum, respectively. The antimicrobial activity was determined by disc diffusion method against selected microbial strains where glucose oxidase from A. niger showed anti-bacterial activity, while no fungicidal effects were shown by both A. niger and P. notatum glucose oxidases.
Huo-Xi Jin; Zhong-Ce Hu; Yu-Guo Zheng
The enantioselective hydrolysis of racemic epichlorohydrin for the production of enantiopure ()-epichloro-hydrin using whole cells of Aspergillus niger ZJB-09173 in organic solvents was investigated. Cyclohexane was used as the reaction medium based on the excellent enantioselectivity of epoxide hydrolase from A. niger ZJB-09173 in cyclohexane. However, cyclohexane had a negative effect on the stability of epoxide hydrolase from A. niger ZJB-09173. In the cyclohexane medium, substrate inhibition, rather than product inhibition of catalysis, was observed in the hydrolysis of racemic epichlorohydrin using A. niger ZJB-09173. The racemic epichlorohydrin concentration was markedly increased by continuous feeding of substrate without significant decline of the yield. Ultimately, 18.5% of ()-epichlorohydrin with 98% enantiomeric excess from 153.6 mM of racemic epichlorohydrin was obtained by the dry cells of A. niger ZJB-09173, which was the highest substrate concentration in the production of enantiopure ()-epichlorohydrin by epoxide hydrolases using an organic solvent medium among the known reports.
Full Text Available Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1 was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B1 after 48 h of fermentation in nutrient broth (NB. Optimization of fermentation conditions for aflatoxin B1 degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B1 was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B1 degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B1 degradation by the supernatant were examined. Results indicated that aflatoxin B1 degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.
Franken, Angelique C W; Lechner, Beatrix E; Werner, Ernst R; Haas, Hubertus; Lokman, B Christien; Ram, Arthur F J; van den Hondel, Cees A M J J; de Weert, Sandra; Punt, Peter J
Iron is an essential metal for many organisms, but the biologically relevant form of iron is scarce because of rapid oxidation resulting in low solubility. Simultaneously, excessive accumulation of iron is toxic. Consequently, iron uptake is a highly controlled process. In most fungal species, siderophores play a central role in iron handling. Siderophores are small iron-specific chelators that can be secreted to scavenge environmental iron or bind intracellular iron with high affinity. A second high-affinity iron uptake mechanism is reductive iron assimilation (RIA). As shown in Aspergillus fumigatus and Aspergillus nidulans, synthesis of siderophores in Aspergilli is predominantly under control of the transcription factors SreA and HapX, which are connected by a negative transcriptional feedback loop. Abolishing this fine-tuned regulation corroborates iron homeostasis, including heme biosynthesis, which could be biotechnologically of interest, e.g. the heterologous production of heme-dependent peroxidases. Aspergillus niger genome inspection identified orthologues of several genes relevant for RIA and siderophore metabolism, as well as sreA and hapX. Interestingly, genes related to synthesis of the common fungal extracellular siderophore triacetylfusarinine C were absent. Reverse-phase high-performance liquid chromatography (HPLC) confirmed the absence of triacetylfusarinine C, and demonstrated that the major secreted siderophores of A. niger are coprogen B and ferrichrome, which is also the dominant intracellular siderophore. In A. niger wild type grown under iron-replete conditions, the expression of genes involved in coprogen biosynthesis and RIA was low in the exponential growth phase but significantly induced during ascospore germination. Deletion of sreA in A. niger resulted in elevated iron uptake and increased cellular ferrichrome accumulation. Increased sensitivity toward phleomycin and high iron concentration reflected the toxic effects of excessive
Singh, Gavendra; Prakash, Soam
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 μl/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.
Full Text Available Aspergillus niger is a fungus of the genus Aspergillus. It has caused a disease called black mold on certain fruits and vegetables. The culture filtrates released from the A. niger ATCC 66566 were grown in Czapek dox broth (CDB then filtered with flash chromatograph and were used for the bioassay after a growth of thirty days. The result demonstrated these mortalities with LC50, LC90, and LC99 values of Culex quinquefasciatus 0.76, 3.06, and 4.75, Anopheles stephensi 1.43, 3.2, and 3.86, and Aedes aegypti 1.43, 2.2, and 4.1 μl/cm2, after exposure of seven hours. We have calculated significant LT90 values of Cx. quinquefasciatus 4.5, An. stephensi 3.54, and Ae. aegypti 6.0 hrs, respectively. This liquid spray of fungal culture isolate of A. niger can reduce malaria, dengue, and filarial transmission. These results significantly support broadening the current vector control paradigm beyond chemical adulticides.
Sharma, Seema; Banerjee, Kaushik; Choudhury, Partha P
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.
Yang, Ying; Yang, Feng; Li, Yan-Hong; Liu, He-Ping; Chen, Xiao-Yan
Aspergillus niger, a saprophytic fungus, is widely distributed in soil, air and cereals, and can cause postharvest diseases in fruit. Polygalacturonase (PG) is one of the main enzymes in fungal pathogens to degrade plant cell wall. To evaluate whether the deletion of an exo-polygalacturonase gene pgxB would influence fungal pathogenicity to fruit, pgxB gene was deleted in Aspergillus niger MA 70.15 (wild type) via homologous recombination. The ΔpgxB mutant showed similar growth behavior compared with the wild type. Pectin medium induced significant higher expression of all pectinase genes in both wild type and ΔpgxB in comparison to potato dextrose agar medium. However, the ΔpgxB mutant was less virulent on apple fruits as the necrosis diameter caused by ΔpgxB mutant was significantly smaller than that of wild type. Results of quantitive-PCR showed that, in the process of infection in apple fruit, gene expressions of polygalacturonase genes pgaI, pgaII, pgaA, pgaC, pgaD and pgaE were enhanced in ΔpgxB mutant in comparison to wild type. These results prove that, despite the increased gene expression of other polygalacturonase genes in ΔpgxB mutant, the lack of pgxB gene significantly reduced the virulence of A. niger on apple fruit, suggesting that pgxB plays an important role in the infection process on the apple fruit. PMID:28257463
de la Cruz, Reynaldo; Ascacio, Juan A; Buenrostro, Juan; Sepúlveda, Leonardo; Rodríguez, Raúl; Prado-Barragán, Arely; Contreras, Juan C; Aguilera, Antonio; Aguilar, Cristóbal N
Ellagic acid is one of the most bioactive antioxidants with important applications in pharmaceutical, cosmetic, and food industries. However, there are few biotechnological processes developed for its production, because it requires precursors (ellagitannins) and the corresponding biocatalyst (ellagitannase). The aim of this study was to optimize the culture conditions for ellagitannase production by Aspergillus niger in solid-state fermentation (SSF). The bioprocess was carried out into a column bioreactor packed with polyurethane foam impregnated with an ellagitannins solution as carbon source. Four strains of Aspergillus niger (PSH, GH1, HT4, and HC2) were evaluated for ellagitannase production. The study was performed in two experimental steps. A Plackett-Burman design was used to determine the influencing parameters on ellagitannase production. Ellagitannins concentration, KCl, and MgSO4 were determined to be the most significant parameters. Box-Behnken design was used to define the interaction of the selected parameters. The highest enzyme value was obtained by A. niger PSH at concentrations of 7.5 g/L ellagitannins, 3.04 g/L KCl, and 0.76 g/L MgSO4. The methodology followed here allowed increasing the ellagitannase activity 10 times over other researcher results (938.8 U/g ellagitannins). These results are significantly higher than those reported previously and represent an important contribution for the establishment of a new bioprocess for ellagic acid and ellagitannase production.
Gong, Weili; Zhang, Huaiqiang; Liu, Shijia; Zhang, Lili; Gao, Peiji; Chen, Guanjun; Wang, Lushan
Filamentous fungi such as Aspergillus spp., Trichoderma spp., and Penicillium spp. are frequently used to produce high concentrations of lignocellulosic enzymes. This study examined the discrepancies in the compositions and dynamic changes in the extracellular enzyme systems secreted by Aspergillus niger ATCC1015, Trichoderma reesei QM9414, and Penicillium oxalicum 114-2 cultured on corn stover and wheat bran. The results revealed different types and an abundance of monosaccharides and oligosaccharides were released during incubation, which induced the secretion of diverse glycoside hydrolases. Both the enzyme activities and isozyme numbers of the three fungal strains increased with time. A total of 279, 161, and 183 secretory proteins were detected in A. niger, T. reesei, and P. oxalicum secretomes, respectively. In the A. niger secretomes, more enzymes involved in the degradation of (galacto)mannan, xyloglucan, and the backbone of pectin distributed mostly in dicots were detected. In comparison, although P. oxalicum 114-2 hardly secreted any xyloglucanases, the diversities of enzymes involved in the degradation of xylan and β-(1,3;1,4)-D-glucan commonly found in monocots were higher. The cellulase system of P. oxalicum 114-2 was more balanced. The degradation preference provided a new perspective regarding the recomposition of lignocellulosic enzymes based on substrate types.
Tribst, Alline A L; Franchi, Mark A; Cristianini, Marcelo; de Massaguer, Pilar R
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.
Full Text Available Abstract 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.
Gomaa, Ola M
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 niger 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.
Frisvad, Jens C; Petersen, Lene M; Lyhne, E Kirstine; Larsen, Thomas O
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.
Braumann, Ilka; van den Berg, Marco; Kempken, Frank
Repeat induced point mutation (RIP) is a gene silencing mechanism present in fungal genomes. During RIP, duplicated sequences are efficiently and irreversibly mutated by transitions from C:G to T:A. For the first time, we have identified traces of RIP in transposable elements of Aspergillus niger and Penicillium chrysogenum, two biotechnologically relevant fungi. We found that RIP in P. chrysogenum has affected a large set of sequences, which also contain other mutations. On the other hand, RIP in A. niger is limited to only few sequences, but literally all mutations are RIP-like. Surprisingly, RIP occurred only in transposon sequences that have disrupted open reading frames in A. niger, a phenomenon not yet reported for other fungi. In both fungal species, we identified two sequences with strong sequence similarity to Neurospora crassa RID. RID is a putative DNA methyltransferase and the only known enzyme involved in the RIP process. Our findings suggest that both A. niger and P. chrysogenum either had a sexual past or have a sexual potential. These findings have important implications for future strain development of these fungi.
Ibtisam Mohammed Ababutain
Full Text Available Indoor airborne fungi have been implicated in human health problems, damage to building materials, books, clothes and stored foods, which effected by different ecological factors. Aspergillus niger and Cladosporium sphaerospermum are the most dominant indoor airborne fungi were obtained from our previous study. The effect of normal indoor conditions (Temperature and Relative Humidity on their growth was studied. Including their nutrients growth requirements. The PDA medium was the appropriate growth medium for Cl. sphaerospermum, with a significant difference at (pA. niger, with no significant difference. The temperatures 25 and 30Â°C favored colony diameter growth for Cl. sphaerospermum and A. niger, respectively with a significant difference at (pCl. sphaerospermum increased to reach its maximum at 100% RH. Whereas, A. niger prefers to grow at lower RH comparing to Cl. sphaerospermum to reach its maximum at 75% RH with a significant difference at (pCl. sphaerospermum can be used as indicator fungi for the high humidity level in residences. The result has proved that keeping the humidity low enough can prevent fungi growth.
Lv, Yangyong; Xiao, Jing; Pan, Li
Genomic studies have shown that not only plants but also filamentous fungi contain type III polyketide synthases. To study the function of type III polyketide synthase (AnPKSIII) in Aspergillus niger, a deletion strain (delAnPKSIII) and an overexpression strain (oeAnPKSIII) were constructed in A. niger MA169.4, a derivative of the wild-type (WT) A. niger ATCC 9029 that produces large quantities of gluconic acid. Alterations in the metabolites were analyzed by HPLC when the extract of the overexpression strain was compared with extracts of the WT and deletion strains. Protocatechuic acid (PCA; 3,4-dihydroxybenzoic acid, 3.2 mg/l) was isolated and identified as the main product of AnPKSIII when inductively expressed in A. niger MA169.4. The molecular weight of PCA was 154.1 (m/z 153.1 [M-H](-)), was detected by ESI-MS in the negative ionization mode, and (1)H and (13)C NMR data confirmed its structure.
Maria T Brandl
Full Text Available Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose-chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens.
Full Text Available In this research, the antifungal role of hydrogen sulfide (H2S on the postharvest pathogens Aspergillus niger and Penicillium italicum growing on fruits and under culture conditions on defined media was investigated. Our results show that H2S, released by sodium hydrosulfide (NaHS effectively reduced the postharvest decay of fruits induced by A. niger and P. italicum. Furthermore, H2S inhibited spore germination, germ tube elongation, mycelial growth, and produced abnormal mycelial contractions when the fungi were grown on defined media in Petri plates. Further studies showed that H2S could cause an increase in intracellular reactive oxygen species (ROS in A. niger. In accordance with this observation we show that enzyme activities and the expression of superoxide dismutase (SOD and catalase (CAT genes in A. niger treated with H2S were lower than those in control. Moreover, H2S also significantly inhibited the growth of Saccharomyces cerevisiae, Rhizopus oryzae, the human pathogen Candida albicans, and several food-borne bacteria. We also found that short time exposure of H2S showed a microbicidal role rather than just inhibiting the growth of microbes. Taken together, this study suggests the potential value of H2S in reducing postharvest loss and food spoilage caused by microbe propagation.
Paun, Linda; Nitsche, Benjamin; Homan, Tim; Ram, Arthur F; Kempken, Frank
The ascomycete Aspergillus niger is widely used in the biotechnology, for instance in producing most of the world's citric acid. It is also known as a major food and feed contaminant. While generation of gene knockouts for functional genomics has become feasible in ku70 mutants, analyzing gene functions or metabolic pathways remains a laborious task. An unbiased transposon-based mutagenesis approach may aid this process of analyzing gene functions by providing mutant libraries in a short time. The Vader transposon is a non-autonomous DNA-transposon, which is activated by the homologous tan1-transposase. However, in the most commonly used lab strain of A. niger (N400 strain and derivatives), we found that the transposase, encoded by the tan1 gene, is mutated and inactive. To establish a Vader transposon-based mutagenesis system in the N400 background, we expressed the functional transposase of A. niger strain CBS 513.88 under the control of an inducible promoter based on the Tet-on system, which is activated in the presence of the antibiotic doxycycline (DOX). Increasing amounts of doxycycline lead to higher Vader excision frequencies, whereas little to none activity of Vader was observed without addition of doxycycline. Hence, this system appears to be suitable for producing stable mutants in the A. niger N400 background.
Colla, Eliane; Santos, Lucielen Oliveira; Deamici, Kricelle; Magagnin, Glênio; Vendruscolo, Mauricio; Costa, Jorge Alberto Vieira
Simultaneous production of amyloglucosidase (AMG) and exo-polygalacturonase (exo-PG) was carried out by Aspergillus niger in substrate of defatted rice bran in a rotating drum bioreactor (RDB) and studied by a 3(1) × 2(2) factorial experimental design. Variables under study were A. niger strains (A. niger NRRL 3122 and A. niger t0005/007-2), types of inoculum (spore suspension and fermented bran), and types of inducer (starch, pectin, and a mix of both). Solid-state fermentation process (SSF) was conducted at 30 °C under 60-vvm aeration for 96 h in a pilot scale. Production of AMG and exo-PG was significantly affected by the fungal strain and the type of inoculum, but inducers did not trigger any significant effect, an evidence of the fact that these enzymes are constitutive. The maximum activity of exo-PG was 84 U gdm(-1) whereas the maximum yield of AMG was 886.25 U gdm(-1).
Lazarovits, G.; Hill, J. [Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, London, Ontario (Canada)]. E-mail: Lazarovitsg@agr.gc.ca; King, R. [Agriculture and Agri-Food Canada, Potato Research Centre, Fredericton, New Brunswick (Canada); Calhoun, L.A. [Univ. of New Brunswick, Dept. of Chemistry, Fredericton, New Brunswick (Canada)
Of several hundred microorganisms randomly selected from the environment, only a fungal isolate identified as Aspergillus niger van Tiegham var. niger was found to transform the phytotoxin thaxtomin A to much less toxic metabolites. The rate and extent of transformation of thaxtomin A was tested under a variety of conditions, including different growth media, biomass concentrations, incubation periods, and shaker speeds. Under optimum conditions the fungus converted thaxtomin A into two major and five minor metabolites. The two major metabolites and three of the five minor metabolites were fully characterized by a combination of mass spectral and nuclear magnetic resonance techniques. When assayed on aseptically produced mini-tubers, the major metabolites proved to be much less phytotoxic than thaxtomin A. (author)
Lv, Yangyong; Zhou, Feng; Wang, Bin; Pan, Li
Oxidative stress is associated with metabolite formation in fungi. In contrast to an Aspergillus niger wild-type strain, a sclerotia-formation regulator ansclR deletion strain demonstrated increased susceptibility to oxidative stress and reduced transcription of the catalase gene, catB, while an ansclR overexpression strain showed enhanced resistance to oxidative stress and increased expression of catB. In addition, ansclR complementation strain expressed a wild-type level of catB. The ansclR overexpression strain also produced the same metabolites as the wild type strain treated with H2O2. Furthermore, LC-MS, NMR, and IR analyses showed that the main metabolite was a steroid analog. Our study adds new clues to oxidative stress-related factors and metabolite formation in A. niger.
Xu, Yanbing; Zheng, Zhaojuan; Xu, Qianqian; Yong, Qiang; Ouyang, Jia
Inulooligosaccharides (IOS) represent an important class of oligosaccharides at industrial scale. An efficient conversion of inulin to IOS through endoinulinase from Aspergillus niger is presented. A 1482 bp codon optimized gene fragment encoding endoinulinase from A. niger DSM 2466 was cloned into pPIC9K vector and was transformed into Pichia pastoris KM71. Maximum activity of the recombinant endoinulinase, 858 U/mL, was obtained at 120 h of the high cell density fermentation process. The optimal conditions for inulin hydrolysis using the recombinant endoinulinase were investigated. IOS were harvested with a high concentration of 365.1 g/L and high yield up to 91.3%. IOS with different degrees of polymerization (DP, mainly DP 3-6) were distributed in the final reaction products.
孙海彦; 黎娟华; 刘恩世; 易小平; 杨景豪; 彭明
从生淀粉低产菌Aspergillus niger F-01和高产菌Aspergillus niger G-1125中克隆到生淀粉糖化酶的启动序列,这两个菌种生淀粉糖化酶基因启动子序列长分别是651bp和613bp,两个启动子都含有真核生物启动子的典型序列CCAAT和TATAAAT,通过序列比对发现,这两个启动子的同源性为84.4%。
孙海彦; 黎娟华; 刘恩世; 易小平; 杨景豪; 彭明
从生淀粉低产菌Aspergillus niger F-01和高产菌Aspergillus niger G-1125中克隆到生淀粉糖化酶的启动序列,这两个菌种生淀粉糖化酶基因启动子序列长分别是651bp和613bp,两个启动子都含有真核生物启动子的典型序列CCAAT和TATA-AAT,通过序列比对发现,这两个启动子的同源性为84.4％.
Li, Jing; Wang, Juan; Li, Jinxin; Liu, Dahui; Li, Hongfa; Gao, Wenyuan; Li, Jianli; Liu, Shujie
In the present study, the culture conditions for the accumulation of Glycyrrhiza uralensis adventitious root metabolites in balloon-type bubble bioreactors (BTBBs) have been optimized. The results of the culture showed that the best culture conditions were a cone angle of 90° bioreactor and 0.4-0.6-0.4-vvm aeration volume. Aspergillus niger can be used as a fungal elicitor to enhance the production of defense compounds in plants. With the addition of a fungal elicitor (derived from Aspergillus niger), the maximum accumulation of total flavonoids (16.12 mg g(-1)) and glycyrrhetinic acid (0.18 mg g(-1)) occurred at a dose of 400 mg L(-1) of Aspergillus niger resulting in a 3.47-fold and 1.8-fold increase over control roots. However, the highest concentration of polysaccharide (106.06 mg g(-1)) was achieved with a mixture of elicitors (Aspergillus niger and salicylic acid) added to the medium, resulting in a 1.09-fold increase over Aspergillus niger treatment alone. Electrospray ionization tandem mass spectrometry (ESI-MS(n)) analysis was performed, showing that seven compounds were present after treatment with the elicitors, including uralsaponin B, licorice saponin B2, liquiritin, and (3R)-vestitol, only identified in the mixed elicitor treatment group. It has also been found that elicitors (Aspergillus niger and salicylic acid) significantly upregulated the expression of the cinnamate 4-hydroxylase (C4H), β-amyrin synthase (β-AS), squalene epoxidase (SE) and a cytochrome P450 monooxygenase (CYP72A154) genes, which are involved in the biosynthesis of bioactive compounds, and increased superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity.
Han, Yanming; Wilson, David B.; Lei, Xin Gen
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) in Saccharomyces 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 was inserted into the expression vector pYES2 and was expressed in S. cerevisiae as an act...
Jenkins, J; Scott, M; Mayans, O; Pickersgill, R; Harris, G; Connerton, I; Gravesen, T
The major secreted pectin lyase (E.C. 220.127.116.11) from Aspergillus niger, strain 4M-147, has been purified and crystallized by the hanging-drop method using polyethylene glycol as precipitant. The crystals belong to the space group P2(1)2(1)2(1) with cell dimensions a = 45.2, b = 83.2, c = 93.1 A (1 A = 0.1 nm) and a single molecule in the asymmetric unit. The crystals diffract to at least 2.0 A resolution and are suitable for structure determination.
Cultivation of an endophytic fungus Aspergillus niger EN-13 that was isolated from the inner tissue of the marine brown alga Colpomenia sinuosa resulted in the characterization of a new naphthoquinoneimine derivative, namely, 5,7-dihydroxy-2-[1-(4-methoxy-6-oxo-6H-pyran-2-yl)-2-phenylethylamino]-[ 1,4]naphthoquinone. The structure of the new compound was established on the basis of various NMR spectroscopic analyses including 2D NMR techniques, EI-MS, and HR-ESI-MS. This compound displayed moderate antifungal activity.
用黑曲霉Aspergillus niger QG 0301进行单宁酶发酵,制得酶制剂.实验结果表明:Aspergillus niger QG 0301进行单宁酶发酵的适宜培养基包括:混合碳源(或玉米淀粉)、硫酸铵、磷酸二氢钾、碳酸钙、硫酸镁、单宁酸;在30℃、120r/min振荡培养5天,单宁酶产量平均为18.55u/mL.
Full Text Available In this paper glucoamylase from Aspergillus niger was immobilized by using a modified version of cross-linked enzyme aggregates (CLEA. The co-aggregates were cross-linked with glutaraldehyde; meanwhile dextrin and xanthan gum as protecting agents were added, which provides high affinity with the enzyme molecules. The immobilized glucoamylase was stable over a broad range of pH (3.0–8.0 and temperature (55–75 °C; dependence shows more catalytic activity than a free enzyme. The thermostability, kinetic behavior, and first-order inactivation rate constant (ki were investigated. The two types of protector made the immobilized glucoamylase more robust than the free form. Both of the immobilized enzymes have excellent recyclability, retaining over 45% of the relative activity after 24 runs. In addition, immobilized enzymes reduced only 40% of the initial activity after three months by the storability measure, indicating high activity.
Neltje Nobertine Palinggi
Full Text Available Penelitian ini dilakukan untuk mendapatkan informasi tentang pengaruh dosis Aspergillus niger dalam bungkil kelapa sawit sebagai bahan pakan pada pembesaran ikan kerapu macan. Ikan uji yang digunakan berukuran bobot rata-rata 23,15±0,23 g; ditebar dalam keramba jaring apung ukuran 1 m x 1 m x 2 m, dengan kepadatan 16 ekor/keramba. Perlakuan yang diuji adalah penambahan Aspergillus niger sebanyak 2, 4, 8, 16 g/kg bungkil kelapa sawit dan kontrol. Masing-masing perlakuan diulang tiga kali dan disain adalah rancangan acak lengkap. Selama pemeliharaan, ikan diberi pakan uji dua kali sehari (pagi dan sore secara satiasi selama 20 minggu. Hasil penelitian menunjukkan bahwa penambahan 8 g Aspergillus niger/kg bungkil kelapa sawit memberikan pertambahan bobot dan laju spesifik lebih tinggi daripada kontrol (P0,05, namun nilainya nyata lebih tinggi (P0.05 among those of the juveniles fed on the diets with 2, 4, 16 g of A. niger/kg palm oil cake. Although the feed efficiency, protein efficiency ratio and protein retention of juveniles fed on the diet with 8 g A. niger/kg palm oil cake were not significantly different (P>0.05 from those of the juveniles fed on the diets with 2 and 4 g of A. niger/kg palm oil cake, those of juveniles the fed diet with 8 g of A. niger/kg palm oil cake were significantly higher (P<0.05 than those of the juveniles fed the diet with 16 g A. niger/kg palm oil cake. The best of growth rate of tiger grouper juveniles occurred at the dosage of 7.8—8.2 g A. niger/kg palm oil cake.
Benoit, Isabelle; Asther, Michèle; Bourne, Yves; Navarro, David; Canaan, Stéphane; Lesage-Meessen, Laurence; Herweijer, Marga; Coutinho, Pedro M; Asther, Marcel; Record, Eric
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.
Dai, Ziyu; Mao, Xingxue; Magnuson, Jon K.; Lasure, Linda L.
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.
Jørgensen, Thomas R; Goosen, Theo; Hondel, Cees A M J J van den
BACKGROUND: The filamentous fungus, Aspergillus niger, responds to nutrient availability by modulating secretion of various substrate degrading hydrolases. This ability has made it an important organism in industrial production of secreted glycoproteins. The recent publication of the A. niger...... the physiology and transcriptome of A. niger growing at the same specific growth rate (0.16 h(-1)) on xylose or maltose in carbon-limited chemostat cultures. Transcription profiles were obtained using Affymetrix GeneChip analysis of six replicate cultures for each of the two growth-limiting carbon sources...
Mogensen, Jesper Mølgaard; Nielsen, Kristian Fog; Samson, Robert A.
Background Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual fumonisin B......2 (FB2) production in four strains of this biotechnologically important workhorse. Results In the present study, a screening of 5 A. niger strains and 25 assumed fumonisin producing Fusarium strains from 6 species, showed that all 5 A. niger strains produced FB2 and 23 of 25 Fusarium produced...... fumonisin B1 and other isoforms (fumonisin B2 and B3). Five A. niger and five Fusarium spp. were incubated at six different temperatures from 15-42°C on Czapek Yeast Agar +5% salt or Potato Dextrose Agar. A. niger had the highest production of FB2 at 25-30°C whereas Fusarium spp. had the maximal production...
Kotik, Michael; Kyslík, Pavel
Purification of a novel enantioselective epoxide hydrolase from Aspergillus niger M200 has been achieved using ammonium sulphate precipitation, ionic exchange, hydrophobic interaction, and size-exclusion chromatography, in conjunction with two additional chromatographic steps employing hydroxylapatite, and Mimetic Green. The enzyme was purified 186-fold with a yield of 15%. The apparent molecular mass of the enzyme was determined to be 77 kDa under native conditions and 40 kDa under denaturing conditions, implying a dimeric structure of the native enzyme. The isoelectric point of the enzyme was estimated to be 4.0 by isoelectric focusing electrophoresis. The enzyme has a broad substrate specificity with highest specificities towards tert-butyl glycidyl ether, para-nitrostyrene oxide, benzyl glycidyl ether, and styrene oxide. Enantiomeric ratios of 30 to more than 100 were determined for the hydrolysis reactions of 4 epoxidic substrates using the purified enzyme at a reaction temperature of 10 degrees C. Product inhibition studies suggest that the enzyme is able to differentiate to a high degree between the (R)-diol and (S)-diol product of the hydrolysis reaction with tert-butyl glycidyl ether as the substrate. The highest activity of the enzyme was at 42 degrees C and a pH of 6.8. Six peptide sequences, which were obtained by cleavage of the purified enzyme with trypsin and mass spectrometry analysis of the tryptic peptides, show high similarity with corresponding sequences originated from the epoxide hydrolase from Aspergillus niger LCP 521.
Singh, O V; Sharma, A; Singh, R P
Aspergillus niger ORS-4, isolated from the sugarcane industry waste materials was found to produce notable level of gluconic acid. From this strain, a mutant Aspergillus niger ORS-4.410 having remarkable increase in gluconic acid production was isolated and compared for fermentation properties. Among the various substrates used, glucose resulted into maximum production of gluconic acid (78.04 g/L). 12% concentration led to maximum production. Effect of spore age and inoculum level on fermentation indicated an inoculum level of 2% of the 4-7 days old spores were best suited for gluconic acid production. Maximum gluconate production could be achieved after 10-12 days of the fermentation at 30 degrees C and at a pH of 5.5. Kinetic analysis of production indicated that growth of the mutant was favoured during initial stages of the fermentation (4-8 days) and production increased during the subsequent 8-12 days of the fermentation. CaCO3 and varying concentrations of different nutrients affected the production of gluconic acid. Analysis of variance for the factors evaluated the significant difference in the production levels.
Kiranmayi, M Usha; Poda, Sudhakar; Vijayalakshmi, M; Krishna, P V
The objective of this study was to determine the influence of natural biowaste substrates such as banana peel powder and coir powder at varying environmental parameters of pH (4-9) and temperature (20-50 degrees C) on the cellulase enzyme production by Aspergillus niger. The cellulase enzyme production was analyzed by measuring the amount of glucose liberated in IU ml(-1) by using the dinitrosalicylic acid assay method. The substrates were pretreated with 1% NaOH (alkaline treatment) and autoclaved. The maximum activity of the enzyme was assayed at varying pH with temperatures being constant and varying temperatures with pH being constant. The highest activity of the enzyme at varying pH was recorded at pH 6 for banana peel powder (0.068 +/- 0.002 IU ml) and coir powder (0.049 +/- 0.002 IU ml(-1)) and the maximum activity of the enzyme at varying temperature was recorded at 35 degrees C for both banana peel powder (0.072 +/- 0.001 IU ml(-1)) and coir powder (0.046 +/- 0.003 IU ml(-1)). At varying temperatures and pH the high level of enzyme production was obtained at 35 degrees C and pH 6 by using both the substrates, respectively. However among the two substrates used for the production of cellulases by Aspergillus niger banana peel powder showed maximum enzymatic activity than coir powder as substrate.
Full Text Available Powdered enzyme was produced by freeze-drying the enzyme solution extracted from 3 days culture of Aspergillus niger ATCC 6275 on palm cake with the addition of 0.2% glucose and 2% urea. The product yield was 38% by weight. The half-life of the enzyme was 9 months keeping at 4ºC. The enzyme was tested with decanter effluent with different characteristics from two palm oil mills. The decanter effluent possessing high suspended solid (SS and low oil (9.5 g/l content was selected for studying the factors affecting the separation of SS and oil as bulking solid. Results indicated that the effluent must contain oil not less than 15 g/l so that the bulking solid would occur from the reaction of the enzyme (with xylanase activity of 200 U/ ml after incubation at 40ºC for 6 h. Minimum concentrations of the enzyme from A. niger ATCC 6275 and commercial xylanase (Meicellase were 200 and 600 U/ml, respectively. The optimum pH was 4.5. Treatment of palm oil mill effluent by the enzyme from A. niger ATCC 6275 for 3 h under the optimum conditions resulted in 78% separation of suspended solids with oil & grease removal of 95% and COD reduction of 35%.
Zhang, Jie; Wu, Xi; Zhang, Shuang-Quan
Antibacterial peptide, CM4 (ABP-CM4), a 35 amino acid peptide from Chinese silkworm-Bombyx mori, displayed a strong antifungal activity against Aspergillus niger, Trichoderma viride and Gibberella saubinetii. Scanning electron microcopy showed that the morphology of conidia became more irregular and swelled when treated with ABP-CM4 at its minimal inhibitory concentration (MIC) of 8 muM. A cell wall regeneration assay indicated that the plasma membrane was the prime target of ABP-CM4 action. Confocal laser scanning microscopy showed that the cytoskeleton of A. niger was destroyed when treated with ABP-CM4 at 8 muM. Furthermore, transmission electron microscopy showed that the membrane and the cellular organelles of fungus were disrupted and there were many vacuoles in the fungal cellular space after the treatment with ABP-CM4. A gel-retardation assay showed that ABP-CM4 bound the DNA of A. niger. Our results suggest that ABP-CM4 exerts its antifungal activity by disrupting the structure of cell membranes and the cytoskeleton and interacts with the organelles, such as the mitochondrion and with the DNA in the fungal cell, subsequently resulting in cell death.
Full Text Available A sheep farmer provided a maize-based brewer's grain (mieliemaroek and bales of Eragrostis curvula hay to ewes and their lambs, kept on zero-grazing in pens. The 'mieliemaroek' was visibly mouldy. After 14 days in the feedlot, clinical signs, including generalised weakness, ataxia of the hind limbs, tremors and recumbency, were noticed. Six ewes died within a period of 7 days. A post mortem examination was performed on 1 ewe. The carcass appeared to be cachectic with mild effusions into the body cavities; mild lung congestion and pallor of the kidneys were observed. Microscopical evaluation revealed nephrosis and birefringent oxalate crystals in the renal tubules when viewed under polarised light. A provisional diagnosis of oxalate nephrosis with subsequent kidney failure was made. Amongst other fungi, Aspergillus niger was isolated from 'mieliemaroek' samples submitted for fungal culture and identification. As A. niger is known to synthesise oxalates, a qualitative screen to detect oxalic acid in the mieliemaroek and purified A. niger isolates was performed using high-performance liquid chromatography (HPLC. Oxalic acid was detected, which supported a diagnosis of soluble oxalate-induced nephropathy.
de Vries, R P; van de Vondervoort, P J I; Hendriks, L; van de Belt, M; Visser, J
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.
Tian, Jun; Wang, Yanzhen; Zeng, Hong; Li, Zongyun; Zhang, Peng; Tessema, Akalate; Peng, Xue
A variety of plant products have been recognized for their antifungal activity and recently have attracted food industry attention for their efficacy in controlling postharvest fungal decay of fruits. The antifungal activity of perillaldehyde (PAE) was evaluated against Aspergillus niger, a known cause of grape spoilage, and possible mechanisms were explored. PAE showed notable antifungal activity against A. niger, with a minimum inhibitory concentration (MIC) and a minimum fungicidal concentration (MFC) of 0.25 and 1 μl/ml, respectively. The accumulation of mycelial biomass was also inhibited by PAE in a dose-dependent manner, completely inhibiting mycelial growth at 1 μl/ml. In vivo data confirmed that the vapour treatment of grapes with various concentrations of PAE markedly improved control of A. niger and suppressed natural decay. Concentrations of PAE of 0.075 μl/ml air showed the greatest inhibition of fungal growth compared to the controls. Further experiments indicated that PAE activated a membrane-active mechanism that inhibits ergosterol synthesis, increases membrane permeability (as evidenced by extracellular pH and conductivity measurements), and disrupts membrane integrity, leading to cell death. Our findings suggest that this membrane-active mechanism makes PAE a promising potential antifungal agent for postharvest control of grape spoilage.
Boriová, Katarína; Urík, Martin; Bujdoš, Marek; Pifková, Ivana; Matúš, Peter
Presence of microorganisms in soils strongly affects mobility of metals. This fact is often excluded when mobile metal fraction in soil is studied using extraction procedures. Thus, the first objective of this paper was to evaluate strain Aspergillus niger's exometabolites contribution on aluminium mobilization. Fungal exudates collected in various time intervals during cultivation were analyzed and used for two-step bio-assisted extraction of alumina and gibbsite. Oxalic, citric and gluconic acids were identified in collected culture media with concentrations up to 68.4, 2.0 and 16.5 mmol L(-1), respectively. These exometabolites proved to be the most efficient agents in mobile aluminium fraction extraction with aluminium extraction efficiency reaching almost 2.2%. However, fungal cultivation is time demanding process. Therefore, the second objective was to simplify acquisition of equally efficient extracting agent by chemically mimicking composition of main organic acid components of fungal exudates. This was successfully achieved with organic acids mixture prepared according to medium composition collected on the 12th day of Aspergillus niger cultivation. This mixture extracted similar amounts of aluminium from alumina compared to culture medium. The aluminium extraction efficiency from gibbsite by organic acids mixture was lesser than 0.09% which is most likely because of more rigid mineral structure of gibbsite compared to alumina. The prepared organic acid mixture was then successfully applied for aluminium extraction from soil samples and compared to standard single step extraction techniques. This showed there is at least 2.9 times higher content of mobile aluminium fraction in soils than it was previously considered, if contribution of microbial metabolites is considered in extraction procedures. Thus, our contribution highlights the significance of fungal metabolites in aluminium extraction from environmental samples, but it also simplifies the
Andersen, M.R.; Salazar, M.P.; Schaap, P.J.
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-p
Levasseur, Anthony; Benoit, Isabelle; Asther, Michèle; Asther, Marcel; Record, Eric
The faeB gene encoding the feruloyl esterase B (FAEB) was isolated from Aspergillus niger BRFM131 genomic DNA. The faeB gene, with additional sequence coding for a C-terminal histidine tag, was inserted into an expression vector under the control of the gpd promoter and trpC terminator and expressed
Krengel, U; Rozeboom, HJ; Kalk, KH; Dijkstra, BW
A family G xylanase from Aspergillus niger has been crystallized using the vapor-diffusion method. Several crystal forms could be obtained using various sodium salts as precipitants. Three of the crystal forms belong to space groups P2(1), P2(1)2(1)2(1) and P4(3) and have cell parameters of approxim
TAMIRES CARVALHO DOS SANTOS
Full Text Available Prickly palm cactus husk was used as a solid - state fermentation support substrate for the production of cellulolytic enzymes using Aspergillus niger and Rhizopus sp. A Box - Behnken design was used to evaluate the effects of water activity, fermentation time and temperature on endoglucanase and total cellulase production. Response Surface Methodology showed that optimum conditions for endoglucanase production were achieved at after 70.35 h of fermentation at 29.56°C and a water activity of 0.875 for Aspergillus niger and after 68.12 h at 30.41°C for Rhizopus sp. Optimum conditions for total cellulase production were achieved after 74.27 h of fermentation at 31.22°C for Aspergillus niger and after 72.48 h and 27.86°C for Rhizopus sp . Water activity had a significant effect on Aspergillus niger endoglucanase production only. In industrial applications, enzymatic characterization is important for optimizing variables such as temperature and pH. In this study we showed that endoglucanase and total cellulase had a high level of thermostability and pH stability in all the enzymatic extracts. Enzymatic deactivation kinetic experiments indicated that the enzymes remained active after the freezing of the crude extract. Based on the results, bioconversion of cactus is an excellent alternative for the production of thermostable enzymes.
Full Text Available In the present investigation the fungi, Aspergillus niger and Nigrospora sp. were employed for decolorization of Synazol red HF-6BN. Decolorization study showed that Aspergillus niger and Nigrospora sp. were able to decolorize 88% and 96% Synazol red 6BN, respectively, in 24 days. It was also studied that 86% and 90% Synazol red containing of dye effluent was decolorized by Aspergillus niger and Nigrospora sp. after 28 days of incubation at room temperature. A fungal-based protein with relative molecular mass of 70 kDa was partially purified and examined for enzymatic characteristics. The enzyme exhibited highest activity at temperature ranging from 40-50[degree sign]C and at pH=6.0. The enzyme activity was enhanced in the presence of metal cations. High performance liquid chromatography analysis confirmed that these fungal strains are capable to degrade Synazol red dye into metabolites. No zones of inhibition on agar plates and growth of Vigna radiata in the presence of dye extracted sample, indicated that the fungal degraded dye metabolites are nontoxic to beneficial micro-flora and plant growth. Aspergillus niger and Nigrospora sp. have promising potential in color removal from textile wastewater-containing azo dyes.
Andersen, Mikael Rørdam; Salazar, Margarita Pena; Schaap, Peter J.
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 enzym...
Plumridge, A.; Hesse, S.J.A.; Watson, A.J.; Lowe, K.C.; Stratford, M.; Archer, D.B.
The growth of the filamentous fungus Aspergillus niger, a common food spoilage organism, is inhibited by the weak acid preservative sorbic acid (trans-trans-2,4-hexadienoic acid). Conidia inoculated at 105/ml of medium showed a sorbic acid MIC of 4.5 mM at pH 4.0, whereas the MIC for the amount of m
van Munster, Jolanda M.; van der Kaaij, Rachel M.; Dijkhuizen, Lubbert; van der Maarel, Marc J. E. C.
The genome of the industrially important fungus Aspergillus niger encodes a large number of glycoside hydrolase family 18 members annotated as chitinases. We identified one of these putative chitinases, Cfcl, as a representative of a distinct phylogenetic clade of homologous enzymes conserved in all
Vondervoort, van de P.J.I.; Groot, de M.J.L.; Ruijter, G.J.G.; Visser, J.
Aspergillus niger is known for its biotechnological applications, such as the use of xylanase enzyme for the degradation of hemicellulose. Depending on culture conditions, several polyols may also be accumulated, such as xylitol during D-xylose oxidation. Also during industrial fermentation of xylos
VANDOORNE, H; DEVRINGER, T
The survival of Candida albicans and Aspergillus niger in O/W creams with different types and concentrations of parabens was studied. The survival was not only dependent on the type and concentration of the preservative, but also on the size of the inoculum. The results are relevant for future propo
Sanchez-Torres, P.; Visser, J.; Benen, J.A.E.
Site-directed-mutagenesis studies were performed on family 1 pectin lyase A (PL1A) from Aspergillus niger to gain insight into the reaction mechanism for the pectin lyase-catalysed beta-elimination cleavage of methylesterified polygalacturonic acid and to stabilize the enzyme at slightly basic pH. O
The 6', 7'-epoxybergamottin (EB) is one of major furanocoumarins in grapefruit. Previously, we have shown that Aspergillus niger has a capability of metabolizing EB into 6', 7'-dihydroxybergamottin (DHB), which is further metabolized to bergaptol and bergaptol-5-sulfate in vivo. In this study, we at...
The Minimum Inhibitory Concentration (MIC) of basil oil, was determined for two pathogenic fungi of rice, Aspergillus niger and Penicillium chrysogenum. The antifungal activity of the basil oil in combination with ionising radiation was then investigated to determine if basil oil caused radiosensit...
A two-year field study was conducted to determine the effects of inoculation techniques on the aggressiveness of Aspergillus niger kernel infection in A. flavus resistant and susceptible maize hybrids. Ears were inoculated with the silk-channel, side-needle, and spray techniques 7 days after midsilk...
Full Text Available Glucoamylase is an exo-type enzyme that converts starch completely into glucose from the non-reducing ends. To meet the industrial requirements for starch processing, a glucoamylase with excellent thermostability, raw-starch degradation ability and high glucose yield is much needed. In the present study we selected the excellent Carbohydrate-Activity Enzyme (CAZyme producer, Bispora sp. MEY-1, as the microbial source for glucoamylase gene exploitation.A glucoamylase gene (gla15 was cloned from Bispora sp. MEY-1 and successfully expressed in Pichia pastoris with a high yield of 34.1 U/ml. Deduced GLA15 exhibits the highest identity of 64.2% to the glucoamylase from Talaromyces (Rasamsonia emersonii. Purified recombinant GLA15 was thermophilic and showed the maximum activity at 70°C. The enzyme was stable over a broad pH range (2.2-11.0 and at high temperature up to 70°C. It hydrolyzed the breakages of both α-1,4- and α-1,6-glycosidic linkages in amylopectin, soluble starch, amylose, and maltooligosaccharides, and had capacity to degrade raw starch. TLC and H1-NMR analysis showed that GLA15 is a typical glucoamylase of GH family 15 that releases glucose units from the non-reducing ends of α-glucans. The combination of Bacillus licheniformis amylase and GLA15 hydrolyzed 96.14% of gelatinized maize starch after 6 h incubation, which was about 9% higher than that of the combination with a commercial glucoamylase from Aspergillus niger.GLA15 has a broad pH stability range, high-temperature thermostability, high starch hydrolysis capacity and high expression yield. In comparison with the commercial glucoamylase from A. niger, GLA15 represents a better candidate for application in the food industry including production of glucose, glucose syrups, and high-fructose corn syrups.
He, Jia-dong; Wang, Yong-dong; Hu, Nan; Ding, Dexin; Sun, Jing; Deng, Qin-wen; Li, Chang-wu; Xu, Fei
Aspergillus niger was inoculated to the roots of five plants, and the Syngonium podophyllum-A. niger combinate system (SPANCS) was found to be the most effective in removing uranium from hydroponic liquid with initial uranium concentration of 5 mg L(-1). Furthermore, the hydroponic experiments on the removal of uranium from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) by the SPANCS were conducted, the inhibitory effect of A. niger on the growth of S. podophyllum in the SPANCS was studied, the accumulation characteristics of uranium by S. podophyllum in the SPANCS were analyzed, and the Fourier transform infrared (FT-IR) and extended X-ray absorption fine structure (EXAFS) spectra were measured. The results show that the removal of uranium by the SPANCS from the hydroponic liquids with initial uranium concentrations of 0.5, 1.0, and 3.0 mg L(-1) reached 98.20, 97.90, and 98.50%, respectively, after 37 days of accumulation of uranium; that the uranium concentrations in the hydroponic liquids decreased to 0.009, 0.021, and 0.045 mg L(-1), respectively, which are lower than the stipulated concentration for discharge of 0.050 mg L(-1) by the People's Republic of China; that A. niger helped to generate more groups in the root of S. podophyllum which can improve the complexing capability of S. podophyllum for uranium; and that the uranium accumulated in the root of S. podophyllum was in the form of phosphate uranyl and carboxylic uranyl.
Grigoriev Igor V
Full Text Available Abstract Background Proteomic data is a potentially rich, but arguably unexploited, data source for genome annotation. Peptide identifications from tandem mass spectrometry provide prima facie evidence for gene predictions and can discriminate over a set of candidate gene models. Here we apply this to the recently sequenced Aspergillus niger fungal genome from the Joint Genome Institutes (JGI and another predicted protein set from another A.niger sequence. Tandem mass spectra (MS/MS were acquired from 1d gel electrophoresis bands and searched against all available gene models using Average Peptide Scoring (APS and reverse database searching to produce confident identifications at an acceptable false discovery rate (FDR. Results 405 identified peptide sequences were mapped to 214 different A.niger genomic loci to which 4093 predicted gene models clustered, 2872 of which contained the mapped peptides. Interestingly, 13 (6% of these loci either had no preferred predicted gene model or the genome annotators' chosen "best" model for that genomic locus was not found to be the most parsimonious match to the identified peptides. The peptides identified also boosted confidence in predicted gene structures spanning 54 introns from different gene models. Conclusion This work highlights the potential of integrating experimental proteomics data into genomic annotation pipelines much as expressed sequence tag (EST data has been. A comparison of the published genome from another strain of A.niger sequenced by DSM showed that a number of the gene models or proteins with proteomics evidence did not occur in both genomes, further highlighting the utility of the method.
Bleichrodt, R; Vinck, A; Krijgsheld, P; van Leeuwen, M R; Dijksterhuis, J; Wösten, H A B
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 μm 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.
Secondary glaucoma associated with bilateral Aspergillus niger endophthalmitis in an HIV-positive patient: case report Glaucoma secundário a endoftalmite bilateral por Aspergillus niger em paciente HIV-positivo: relato de caso
Jayter Silva Paula
Full Text Available Aspergillus endophthalmitis is usually related to systemic or local dissemination in immunosuppressed subjects. The authors report a rare case of severe bilateral glaucoma secondary to an intraocular infection with Aspergillus niger, in the absence of any detectable focus of aspergillosis, in an HIV-infected patient. There were no confirming signs of injection drug use, and the agent was isolated after inoculation in experimental animals. This case shows that Aspergillus endophthalmitis should be considered in non-injecting drug users and HIV-infected patients even in the absence of systemic aspergillosis.Endoftalmite por Aspergillus é geralmente relacionada à disseminação local ou sistêmica do agente em indivíduos imunocomprometidos. Os autores relatam um caso raro de glaucoma bilateral grave secundário a uma infecção intra-ocular por Aspergillus niger, na ausência de qualquer foco detectável de aspergilose em paciente HIV-positivo. Foram afastados sinais e antecedentes de uso de drogas injetáveis e o agente foi isolado após inoculação em animais experimentais. Este caso demonstra que a endoftalmite por Aspergillus deve ser considerada em pacientes HIV-positivos não-usuários de drogas injetáveis, mesmo na ausência de aspergilose sistêmica.
Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro
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 18.104.22.168), 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.
Romanowska, Irena; Polak, Jacek; Bielecki, Stanisław
Xylanase of low molecular weight (K II) was isolated from the fungus Aspergillus niger IBT-90 cultivated in medium with wheat bran. K II was purified by precipitation with ammonium sulphate (20-80% saturation) and gel filtration on Biogel P-10. This enzyme is most active in hydrolysis of birchwood xylan at 50 degrees C and pH 5.5. Xylanase K II has an ability to degrade 1,4-beta-bonds and to debranch substrates. It degrades not only xylans but also cellulose, an important factor for its application in bakery. Ag+, Fe3+ and NBS are strong inhibitors of the enzyme. DTT and Na+ activate xylanase K II by 24 and 13%, respectively. Enzyme K II used as additive to flour improves dough properties, increases the volume of wheat-rye and whole meal bread, and increases the porosity of crumb and the moisture of the final product, consequently extending the shelf life of bread.
Sánchez-Marroquín, A; Carreño, R; Ledezma, M
Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of Aspergillus niger in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH(4)NO(3), 0.20; KH(2)PO(4), 0.10; MgSO(4).7H(2)O, 0.025; and (mg/liter): FeSO(4), 0.15 to 0.75; ZnSO(4), 0.10; and CuSO(4), 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%, pH of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements.
Meijer, Susan Lisette; Otero, José Manuel; Olivares Hernandez, Roberto
glyoxylate would increase, leading to excess formation of malate and succinate compared to the wild-type. However, metabolic network analysis showed that an increased icl expression did not result in an increased glyoxylate bypass flux. The analysis did show a global response with respect to gene expression......In order to improve the production of succinate and malate by the filamentous fungus Aspergillus niger the activity of the glyoxylate bypass pathway was increased by over-expression of the isocitrate lyase (icl) gene. The hypothesis was that when isocitrate lyase was up-regulated the flux towards......, leading to an increased flux through the oxidative part of the TCA cycle. Instead of an increased production of succinate and malate, a major increase in fumarate production was observed. The effect of malonate, a competitive inhibitor of succinate dehydrogenase (SDH), on the physiological behaviour...
Full Text Available Microbial transformation of imbricatolic acid (1 by Aspergillus niger afforded 1ÃŽÂ±-hydroxyimbricatolic acid (2, while transformation with Rhizopus nigricans yielded 15-hydroxy-8,17-epoxylabdan-19-oic acid (3. When the diterpene 1 was added to a Cunninghamella echinulata culture, the main products were the microbial metabolites mycophenolic acid (4 and its 3-hydroxy derivative 5. All the structures were elucidated by spectroscopic methods. The cytotoxicity of these compounds towards human lung fibroblasts and AGS cells was assessed. While 4 and 5 showed low cytotoxicity, with IC50 values > 1000 ÃŽÂ¼M against AGS cells and fibroblasts, 1ÃŽÂ±-hydroxyimbricatolic acid (2 presented moderate toxicity towards these targets, with IC50 values of 307 and 631 ÃŽÂ¼M, respectively. The structure of 2 is presented for the first time.
Vassilev, N B; Vassileva, M C; Spassova, D I
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 successfully reused with higher levels of product formation being maintained for longer period (65-70 h) than free cells. The highest gluconic acid concentration of about 143 g l-1 was reached on hydrol-based production medium with 0.3-cm3 foam cubes in the bubble column, where the effect of more suitable aeration and particle volume: medium volume ratio scheme was also investigated.
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 g/kg dry figs, respectively), citric acid yield (8%), and gluconic acid yield (63%) were obtained at a moisture level of 75%, initial pH 7.0, temperature 30 degrees C, and fermentation time in 15 days. However, the highest biomass dry weight (40 g/kg wet substrate) and sugar utilization (90%) were obtained in cultures grown at 35 degrees C. The addition of 6% (w/w) methanol into substrate increased the concentration of citric and gluconic acid from 64 and 490 to 96 and 685 g/kg dry fig, respectively.
Full Text Available Biocontamination within the international space station is ever increasing mainly due to human activity. Control of microorganisms such as fungi and bacteria are important to maintain the well-being of the astronauts during long-term stay in space since the immune functions of astronauts are compromised under microgravity. For the first time control of the growth of an opportunistic pathogen, Aspergillus niger, under microgravity is studied in the presence of α-aminophosphonate chitosan. A low-shear modelled microgravity was used to mimic the conditions similar to space. The results indicated that the α-aminophosphonate chitosan inhibited the fungal growth significantly under microgravity. In addition, the inhibition mechanism of the modified chitosan was studied by UV-Visible spectroscopy and cyclic voltammetry. This work highlighted the role of a bio-based chitosan derivative to act as a disinfectant in space stations to remove fungal contaminants.
Khattab, A A; Bazaraa, W A
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.
Xu, S X; Qin, X; Liu, B; Zhang, D Q; Zhang, W; Wu, K; Zhang, Y H
The pectin lyase gene pnl-zj5a from Aspergillus niger ZJ5 was identified and expressed in Pichia pastoris. PNL-ZJ5A was purified by ultrafiltration, anion exchange and gel chromatography. The Km and Vmax values determined using citrus pectin were 0.66 mg ml(-1) and 32.6 μmol min(-1) mg(-1) , respectively. PNL-ZJ5A exhibited optimal activity at 43°C and retained activity over 25-50°C. PNL-ZJ5A was optimally active at pH 5 and effective in apple juice clarification. Compared with controls, PNL-ZJ5A increased the fruit juice yield significantly. Furthermore, PNL-ZJ5A reduced the viscosity of apple juice by 38.8% and increased its transmittance by 86.3%. PNL-ZJ5A combined with a commercial pectin esterase resulted in higher juice volume.
Full Text Available In this study, the effect of agitation and aeration rates on xylanase activity of Aspergillus niger SS7 in 3-litre stirred tank bioreactor was investigated. The agitation rates tested were 100, 200 and 300 rpm at each airflow rates of 0.5, 1.0 and 1.5 vvm. The maximum xylanase activity in mono- agitator system was at the agitation speed of 200 rpm and aeration rate of 1.0 vvm. In bi-agitator system, at low agitation speed (100 rpm, the xylanase activity was enhanced by 13% compared to mono- agitator system for an aeration rate of 1.0 vvm. Xylanase productivity in continuous culture was higher by approximately 3.5 times than in batch culture.
ZHENG Lai-jiu; DU Bing; HUANG Xiu-bao
In this paper, the aerobic metabolism mechanism of Aspergillus Niger (AS 3.3 50), which is the most suitable bacteria for degumming kenaf fiber, is expounded, and macromolecular structure of pectin is also analyzed.The fracture position of the macromolecular chain of kenaf pectin and its outgrowth structure, affected by Endo-PG and Exo-PG are secreted by AS 3. 350 and explored in molecule scale. The optimal value of degumming parameters are fixed: temperature 34 - 36℃, time 48 - 50 h, pH 6.5 - 7.5. Compared with kenaf fibers obtained by natural method, the ones degummed by bio-enzymatic method possess of smoother surface, better, separation, less impairment and higher: strength with. residual pectin percentage of 14.5 %.
Rusakov, A. V.; Frank-Kamenetskaya, O. V.; Gurzhiy, V. V.; Zelenskaya, M. S.; Izatulina, A. R.; Sazanova, K. V.
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.
Full Text Available Agro-industrial residues are primarily composed of complex polysaccharides that strengthen microbial growth for the production of industrially important enzymes. Pectinases are one of the most widely disseminated enzymes in bacteria, fungi and plants. Czapeck media supplemented with orange waste peel as carbon source under submerged fermentation process Aspergillus niger presenting the preeminent enzymatic production. On partial optimization culture showed the maximum enzyme yield (117.1 ± 3.4 μM/mL/min at 30 °C in an orange waste peel medium having pH 5.5 and substrate concentration (4% after 5th day of fermentation. The produced enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography. A purification fold of 5.59 with specific activity and % recovery of 97.2 U/mg and 12.96% was achieved respectively after gel filtration chromatographic technique. The molecular weight of purified pectinase from A. niger was 30 kDa evidenced by SDS-PAGE. Pectinase activity profile showed purified enzyme was optimally active at pH = 7 and 55 °C. The maximum production of pectinase in the presence of cheaper substrate at low concentration makes the enzyme useful in industrial sectors especially for textile and juice industry.
Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo; Costa, Maurício Dutra
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.
Lopes, Fernanda Cortez; Silva, Lucas André Dedavid e; Tichota, Deise Michele; Daroit, Daniel Joner; Velho, Renata Voltolini; Pereira, Jamile Queiroz; Corrêa, Ana Paula Folmer; Brandelli, Adriano
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
Tan, K H; Ferguson, L B; Carlton, C
The filamentous fungus, Aspergillus niger, efficiently converted cassava polysaccharides to mycelial mass, simple sugars, and acids during the course of its growth. A typical 70-ml culture broth containing 2% cassava polysaccharides yielded 0.38 g dry mycelial mass, 1.14 mmol reducing sugars, and 1.17 meq acids at the end of 42 h. About 70% of the initial total carbohydrate in the medium was degraded during the same period. The sugars and acids in the culture broths were analyzed by HPLC on a single Aminex HPX-87 column at 55 degrees C, using 0.013 N H2SO4 as the eluting solvent. Cassava polysaccharides were degraded to oligosaccharides, maltotriose, maltose, and glucose beyond the 20-h growth periods, with maltotriose emerging as the major simple sugar. The appearance of citric, malic, gluconic, succinic, and fumaric acids accounted mostly for the decreasing pH in the growth media. Formation of carbohydrate species in the culture broths was closely related to the biosynthesis and secretion of several carbohydrases by A. niger. The extracellular carbohydrases were separated and identified by chromatofocusing and polyacrylamide gel electrophoresis to be amyloglucosidase (EC 22.214.171.124), alpha-amylase (EC 126.96.36.199), and alpha-glucosidase (EC 188.8.131.52), respectively.
Fernanda Cortez Lopes
Full Text Available 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.
Full Text Available Aims: The aim of this work was to develop an effective bioprocess to enhance the pectinase production by solid-state cultures of Aspergillus niger HFM-8. Methodology and results: The pectinase production produced by A. niger HFM-8 was studied under solid state fermentation using Malaysian pomelo (Citrus grandis peel as the substrate. This local agricultural waste is rich with lignocellulolytic material including pectin acts as the inducer of pectinase production. Under optimized conditions, 5 g of 0.75 mm pomelo peel size, moisture content of 60% (v/w sterile distilled water pH 5.0, inoculums size of 1x10^4 spores/mL, cultivation temperature of room temperature (30 ± 2 °C, no mixing incurred and with the addition of 1% (w/w citrus pectin and 0.1% (w/w urea has produced pectinase production of 306.89 U/g substrate and 0.78 mg glucosamine/g substrate of fungal growth on the 8th day of cultivation. Conclusion, significance and impact of study: There was 48.82% increment in enzyme production after the improvement of parameters. It was found that pomelo peel is a suitable feedstock for pectinase production.
Wani, Masood Ahmed; Sanjana, Kaul; Kumar, Dhar Manoj; Lal, Dhar Kanahya
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.
Benoit, Isabelle; Zhou, Miaomiao; Vivas Duarte, Alexandra; Downes, Damien J; Todd, Richard B; Kloezen, Wendy; Post, Harm; Heck, Albert J R; Maarten Altelaar, A F; de Vries, Ronald P
Degradation of plant biomass to fermentable sugars is of critical importance for the use of plant materials for biofuels. Filamentous fungi are ubiquitous organisms and major plant biomass degraders. Single colonies of some fungal species can colonize massive areas as large as five soccer stadia. During growth, the mycelium encounters heterogeneous carbon sources. Here we assessed whether substrate heterogeneity is a major determinant of spatial gene expression in colonies of Aspergillus niger. We analyzed whole-genome gene expression in five concentric zones of 5-day-old colonies utilizing sugar beet pulp as a complex carbon source. Growth, protein production and secretion occurred throughout the colony. Genes involved in carbon catabolism were expressed uniformly from the centre to the periphery whereas genes encoding plant biomass degrading enzymes and nitrate utilization were expressed differentially across the colony. A combined adaptive response of carbon-catabolism and enzyme production to locally available monosaccharides was observed. Finally, our results demonstrate that A. niger employs different enzymatic tools to adapt its metabolism as it colonizes complex environments.
Horeh, N. Bahaloo; Mousavi, S. M.; Shojaosadati, S. A.
In this paper, a bio-hydrometallurgical route based on fungal activity of Aspergillus niger was evaluated for the detoxification and recovery of Cu, Li, Mn, Al, Co and Ni metals from spent lithium-ion phone mobile batteries under various conditions (one-step, two-step and spent medium bioleaching). The maximum recovery efficiency of 100% for Cu, 95% for Li, 70% for Mn, 65% for Al, 45% for Co, and 38% for Ni was obtained at a pulp density of 1% in spent medium bioleaching. The HPLC results indicated that citric acid in comparison with other detected organic acids (gluconic, oxalic and malic acid) had an important role in the effectiveness of bioleaching using A. niger. The results of FTIR, XRD and FE-SEM analysis of battery powder before and after bioleaching process confirmed that the fungal activities were quite effective. In addition, bioleaching achieved higher removal efficiency for heavy metals than the chemical leaching. This research demonstrated the great potential of bio-hydrometallurgical route to recover heavy metals from spent lithium-ion mobile phone batteries.
Benoit, Isabelle; van den Esker, Marielle H; Patyshakuliyeva, Aleksandrina; Mattern, Derek J; Blei, Felix; Zhou, Miaomiao; Dijksterhuis, Jan; Brakhage, Axel A; Kuipers, Oscar P; de Vries, Ronald P; Kovács, Ákos T
Interaction between microbes affects the growth, metabolism and differentiation of members of the microbial community. While direct and indirect competition, like antagonism and nutrient consumption have a negative effect on the interacting members of the population, microbes have also evolved in nature not only to fight, but in some cases to adapt to or support each other, while increasing the fitness of the community. The presence of bacteria and fungi in soil results in various interactions including mutualism. Bacilli attach to the plant root and form complex communities in the rhizosphere. Bacillus subtilis, when grown in the presence of Aspergillus niger, interacts similarly with the fungus, by attaching and growing on the hyphae. Based on data obtained in a dual transcriptome experiment, we suggest that both fungi and bacteria alter their metabolism during this interaction. Interestingly, the transcription of genes related to the antifungal and putative antibacterial defence mechanism of B. subtilis and A. niger, respectively, are decreased upon attachment of bacteria to the mycelia. Analysis of the culture supernatant suggests that surfactin production by B. subtilis was reduced when the bacterium was co-cultivated with the fungus. Our experiments provide new insights into the interaction between a bacterium and a fungus.
Xiao, Chunqiao; Wu, Xiaoyan; Chi, Ruan
High-phosphorus iron ore is traditionally dephosphorized by chemical process with inorganic acids. However, this process is not recommended nowadays because of its high cost and consequent environmental pollution. With the current tendency for development of a low-cost and eco-friendly process, dephosphorization of high-phosphorus iron ore through microbial process with three different sources of Aspergillus niger strains was studied in this study. Results show that the three strains of A. niger could grow well in the broth, and effectively remove phosphate from high-phosphorus iron ore during the experiments. Meanwhile, the total iron in the broth was also increased. Acidification of the broth seemed to be the major mechanism for the dephosphorization by these strains. High-pressure liquid chromatography analysis indicated that various organic acids were secreted in the broth, which caused a significant drop of the broth pH. Scanning electron microscopy of ore residues revealed that the high-phosphorus iron ore was obviously destroyed by the actions of these strains. Ore residues by energy-dispersive X-ray microanalysis and Fourier transform infrared spectroscopy indicated that the phosphate was obviously removed from the high-phosphorus iron ore. The optimization of the dephosphorization by these strains was also investigated, and the maximum percentages of phosphate removal were recorded at temperature 27-30 °C, initial pH 5.0-6.5, particle size 0.07-0.1 mm, and pulp density of 2-3% (w/v), respectively. The fungus A. niger was found to have good potential for the dephosphorization of high-phosphorus iron ore, and this microbial process seems to be economic and effective in the future industrial application.
Alkhatib, Mayson H; Aly, Magda M; Rahbeni, Rajaa A; Balamash, Khadijah S
Background Microemulsions (MEs), which consist of oil, water, surfactants, and cosurfactants, have recently generated considerable interest as antimicrobial agents. Objectives To determine the antifungal and antiviral activities of three ME formulations (MEa, MEb, and MEc) that differ in their hydrophilicity. Methods The ME formulas were produced by mixing different fractions of Tween 80, Span 20, ethanol, oil, isopropyl myristate, and distilled water. The antifungal activity of the ME formulas against Aspergillus niger, A. flavus, Bacillus, Candida albicans, and C. glabrata were determined by the solid medium diffusion cytotoxicity test against the mitochondria, measuring the minimum inhibitory concentration, dry biomass, and leakage of potassium, and characterizing the cell morphology. The antiviral activities of the ME formulas against the herpes simplex virus type 2 (HSV-2) were determined using the cytopathic effect assay. Results Significant antimicrobial activities were recorded against A. niger and herpes simplex virus type 2 (HSV-2) when treated with MEb that had hydrophobic nanodroplets with an average diameter of 4.7 ± 1.22 nm. A volume of 0.1 mL of MEb (10 mL of potato dextrose broth) inhibited the germination of A. niger cells, reduced their dry biomass, enhanced the leakage of potassium from the cell membranes, affected their mitochondria, and altered the shape of their conidia, in addition to enlarging them. MEb was able to destroy the HSV-2 virus at a 200-fold dilution in Dulbecco’s modified eagle medium. Conclusions The water-in-oil ME with equivalent surfactant-to-oil ratio (MEb) has great potential as an antifungal and antiviral agent.
Månsson, Maria; Klejnstrup, Marie Louise; Phipps, Richard Kerry
A new fumonisin, fumonisin B-6 (1), has been isolated by cation-exchange and reverse-phase chromatography, together with fumonisin B-2 (2), from,stationary cultures of the fungus Aspergillus niger NRRL 326. Analysis of mass spectrometric and NMR data determined that FB6 is a positional isomer...... of FBI and iso-FB1, having hydroxyl functions at C3, C4, and C5. Analysis of the NMR data for FB2 showed very similar chemical shift values when compared to an authentic Fusarium FB2 standard, strongly indicating identical molecules despite that an absolute stereochemical assignment of FB2 from A. niger...
Ajayi, A A; Peter-Albert, C F; Akeredolu, M; Shokunbi, A A
Two varieties of tomato fruits commonly available in Nigerian markets are the Roma VF and Ibadan local varieties of tomato fruits. The Roma VF fruits are oval in shape. It is a common type of cultivar in the Northern region of Nigeria and it is not susceptible to cracking. The Ibadan local variety of tomato fruits is a local variety commonly found on farmers fields in South-western region of Nigeria. They are highly susceptible to cracking. The Ibadan local variety was employed for this research. There are lots of benefits derived from the consumption of tomato fruits. The fruits can be made into tomato juice clarified with pectinases. Polygalacturonase is one of the pectinases used commercially in the clarification of fruit juice from different fruits. This study examined the production of polygalacturonase during the deterioration of tomato fruits by Aspergillus niger and the role of the purified polygalacturonase in the clarification of tomato juice. Tomato fruits of the Ibadan local variety were inoculated with mycelia discs containing spores of a 96-h-old culture of Aspergillus niger served as the inoculum. The organism from the stock culture was subcultured onto potato dextrose agar plates. The extraction of polygalacturonase after 10 days of incubation at 27 degrees C was carried out by homogenizing the fruits with liquid extractant using the MSE homogenizer after the deteriorated fruits had been chilled for 30 min inside a freezer. Control fruits were similarly treated except that sterile potato dextrose agar served as the inoculum. The effect of different temperature of incubation and different volume of enzyme on the tomato juice from the tomato fruits was investigated. Extracts from the inoculated fruits exhibited appreciable polygalacturonase activity. The juice with polygalacturonase was visually clearer and more voluminous than the juice treated with water for all parameters studied. The highest volume of juice was obtained after an incubation period
Sørensen, Louise Marie; Lametsch, Rene; Andersen, Mikael Rørdam
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...
Full Text Available Aspergillus species (A flavus and A niger are important sources of inhalant allergens. Current diagnostic modalities employ crude Aspergillus extracts which only indicate the source to which the patient has been sensitized, without identifying the number and type of allergens in crude extracts. We report a study on the identification of major and minor allergens of the two common airborne Aspergillus species and heterogeneity of patients’ IgE response to them.Skin prick tests were performed on 300 patients of bronchial asthma and/or allergicrhinitis and 20 healthy volunteers. Allergen specific IgE in patients’ sera was estimated by enzyme allergosorbent test (EAST. Immunoblots were performed to identify major/minor allergens of Aspergillus extracts and to study heterogeneity of patients’ IgE response to them.Positive cutaneous responses were observed in 17% and 14.7% of patients with A flavusand A niger extracts, respectively. Corresponding EAST positivity was 69.2% and 68.7%. In immunoblots, 5 allergenic proteins were identified in A niger extract, major allergens being49, 55.4 and 81.5 kDa. Twelve proteins bound patients’ IgE in A flavus extract, three being major allergens (13.3, 34 and 37 kDa. The position and slopes of EAST binding and inhibition curves obtained with individual sera varied from patient to patient. The number and molecular weight of IgE-binding proteins in both the Aspergillus extracts varied among patients.These results gave evidence of heterogeneity of patients’ IgE response to major/minorAspergillus allergens. This approach will be helpful to identify disease eliciting molecules in the individual patients (component resolved diagnosis and may improve allergen-specific immunotherapy.
Vermani, Maansi; Vijayan, Vannan Kandi; Agarwal, Mahendra Kumar
Aspergillus species (A. flavus and A. niger) are important sources of inhalant allergens. Current diagnostic modalities employ crude Aspergillus extracts which only indicate the source to which the patient has been sensitized, without identifying the number and type of allergens in crude extracts. We report a study on the identification of major and minor allergens of the two common airborne Aspergillus species and heterogeneity of patients' IgE response to them. Skin prick tests were performed on 300 patients of bronchial asthma and/or allergic rhinitis and 20 healthy volunteers. Allergen specific IgE in patients' sera was estimated by enzyme allergosorbent test (EAST). Immunoblots were performed to identify major/minor allergens of Aspergillus extracts and to study heterogeneity of patients'IgE response to them. Positive cutaneous responses were observed in 17% and 14.7% of patients with A. flavus and A. niger extracts, respectively. Corresponding EAST positivity was 69.2% and 68.7%. In immunoblots, 5 allergenic proteins were identified in A. niger extract, major allergens being 49, 55.4 and 81.5 kDa. Twelve proteins bound patients' IgE in A. flavus extract, three being major allergens (13.3, 34 and 37 kDa). The position and slopes of EAST binding and inhibition curves obtained with individual sera varied from patient to patient. The number and molecular weight of IgE-binding proteins in both the Aspergillus extracts varied among patients. These results gave evidence of heterogeneity of patients' IgE response to major/minor Aspergillus allergens. This approach will be helpful to identify disease eliciting molecules in the individual patients (component resolved diagnosis) and may improve allergen-specific immunotherapy.
Wang, Xiao Qiang; Wang, Qun Hui; Liu, Ying Ying; Ma, Hong Zhi
Kitchen waste from dining rooms accounts for a considerable proportion of municipal solid garbage, and economical recycle ways are needed to be developed. This study investigated glucoamylase production from kitchen waste and the feasibility of kitchen waste hydrolysis by the crude enzymes produced. The key problems of high water content and poor porosity in kitchen waste for glucoamylase production under solid-state fermentation could be solved readily by the addition of corn stover or paddy husk. As a support medium, corn stover was better than paddy husk. Smashed kitchen waste (sKW) mixed with corn stover in the ratio of 3.75 : 1 (dry basis) produced 1838 U g(-1) of glucoamylase by Aspergillus niger UV-60 within 96 h. The enzyme productivity from kitchen waste was over two-fold higher than that from wheat bran with additional nutrients. Without any recovery treatment, the produced glucoamylase could be used directly to hydrolyse sKW slurry. The optimum enzyme dose 8% (crude enzyme/kichen waste, w/w) was not too big, and was sufficient to hydrolyse 10% (dry basis) sKW slurry to produce a maximum amount of reducing sugar of 55.4 g L(-1).
Yin, Chao; Wang, Bin; He, Pan; Lin, Ying; Pan, Li
Aspergillus niger is usually regarded as a beneficial species widely used in biotechnological industry. Obtaining the genome sequence of the widely used aconidial A. niger SH2 strain is of great importance to understand its unusual production capability. In this study we assembled a high-quality genome sequence of A. niger SH2 with approximately 11,517 ORFs. Relatively high proportion of genes enriched for protein expression related FunCat items verify its efficient capacity in protein production. Furthermore, genome-wide comparative analysis between A. niger SH2 and CBS513.88 reveals insights into unique properties of A. niger SH2. A. niger SH2 lacks the gene related with the initiation of asexual sporulation (PrpA), leading to its distinct aconidial phenotype. Frame shift mutations and non-synonymous SNPs in genes of cell wall integrity signaling, β-1,3-glucan synthesis and chitin synthesis influence its cell wall development which is important for its hyphal fragmentation during industrial high-efficiency protein production.
Sealy-Lewis, H M; Fairhurst, V
Acetate-non-utilizing mutants in Aspergillus niger were selected by resistance to 1.2% propionate in the presence of 0.1% glucose. Mutants showing normal morphology fell into two complementation groups. One class of mutant lacked acetyl-CoA synthetase but had high levels of isocitrate lyase, while the second class showed reduced levels of both acetyl-CoA synthetase and isocitrate lyase compared to the wild-type strain. By analogy with mutants selected by resistance to 1.2% propionate in Aspergillus nidulans, the properties of the mutants in A. niger suggest that the mutations are either in the structural gene for acetyl-CoA synthetase (acuA) or in a possible regulatory gene of acetate induction (acuB). A third class of mutant in a different complementation group was obtained which had abnormal morphology (yellow mycelium and few conidia); the specific lesion in these mutants has not been determined.
Juliet Bamidele Akinyele
Full Text Available This study aimed at screening of selected fungal strains and optimization of process parameters for cellulases production in submerged fermentation. Aspergillus niger NSPR012 was selected for further studies as the most potent in producing cellulase of high activity. Utilization of various agro-wastes as substitute tocarboxy methyl cellulose (CMC for cellulase production was also investigated. Among tested carbon sources, banana peels at a concentration of 5% was found to be the most effective carbon source. The cellulase production by Aspergillus niger NSPR012 in mineral salt medium attained maximum after 96 h of incubation. Maximum cellulase activity (0.466µmol/min/mL was obtained with locust beans as the best organic nitrogen source. The optimum incubation temperature and initial pH were 37°C and 5.5, respectively. With this information, banana peels could have good biotechnological potential for bio-products formation in which cellulase is one.
Valentine Enyinna Anyanwu; Phillip O. Okerentugba
Microbial production of citric acid by a novel Aspergillus niger EE-12 and its UV – treated strain (UV-1) were carried out in shake flask cultures using mineral salt media containing sucrose or fructose as the carbon and energy sources. The highest citric acid concentration (36.1g/l) was obtained with the UV – treated strain UV-1 after 144 hours in medium containing sucrose and this was significantly higher (p
Mostafa, Yasser S.; Alamri, Saad A.
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 appear...
Carol S. Maguinsay; Franco G. Teves
This study aimed to assess the potential of pineapple waste as substrate for β-Glucosidaseproduction by Aspergillus niger under submerged fermentation. β-Glucosidase activities of crude enzymeextract from cultures maintained with pineapple substrate and with the commercial substratecarboxymethyl cellulose (CMC) were assayed and compared. The assay conducted at different periods offermentation shows that enzymatic activities were generally higher on cultures maintained with CMC.However, β-Gluc...
Khatri, Bhim Prakash; Bhattarai, Tribikram; Shrestha, Sangita; Maharjan, Jyoti
Pectinase enzymes are one of the commercially important enzymes having great potential in various industries especially in food industry. Pectinases accounts for 25 % of global food enzymes produced and their market is increasing day by day. Therefore, the exploration of microorganism with novel characteristics has always been the focus of the research. Microorganism dwelling in unique habitat may possess unique characteristics. As such, a pectinase producing fungus Aspergillus niger strain M...
Frisvad Jens C
Full Text Available Abstract Background Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual fumonisin B2 (FB2 production in four strains of this biotechnologically important workhorse. Results In the present study, a screening of 5 A. niger strains and 25 assumed fumonisin producing Fusarium strains from 6 species, showed that all 5 A. niger strains produced FB2 and 23 of 25 Fusarium produced fumonisin B1 and other isoforms (fumonisin B2 and B3. Five A. niger and five Fusarium spp. were incubated at six different temperatures from 15-42°C on Czapek Yeast Agar +5% salt or Potato Dextrose Agar. A. niger had the highest production of FB2 at 25-30°C whereas Fusarium spp. had the maximal production of FB1 and FB2 at 20-25°C. Addition of 2.5-5% NaCl, or 10-20% sucrose increased the FB2 production of A. niger, whereas addition of glycerol reduced FB2 production. All three water activity lowering solutes reduced the fumonisin production of the Fusarium species. Conclusion The present study shows that the regulation of fumonisin production is very different in A. niger and Fusarium, and that food and feeds preserved by addition of sugar or salts may be good substrates for fumonisin B2 production by A. niger.
Ikram-Ul, Haq; Ali, Sikander; Qadeer, M A; Iqbal, Javed
The present investigation deals with citric acid production by some selected mutant strains of Aspergillus niger from cane molasses in 250 ml Erlenmeyer flasks. For this purpose, a conidial suspension of A. niger GCB-75, which produced 31.1 g/l citric acid from 15% (w/v) molasses sugar, was subjected to UV-induced mutagenesis. Among the 3 variants, GCM-45 was found to be a better producer of citric acid (50.0 +/- 2a) and it was further improved by chemical mutagenesis using N-methyl, N-nitro-N-nitroso-guanidine (MNNG). Out of 3,2-deoxy-D-glucose resistant variants, GCMC-7 was selected as the best mutant, which produced 96.1 +/- 1.5 g/l citric acid 168 h after fermentation of potassium ferrocyanide and H2SO4 pre-treated blackstrap molasses in Vogel's medium. On the basis of kinetic parameters such as volumetric substrate uptake rate (Qs), and specific substrate uptake rate (qs), the volumetric productivity, theoretical yield and specific product formation rate, it was observed that the mutants were faster growing organisms and produced more citric acid. The mutant GCMC-7 has greater commercial potential than the parental strain with regard to citrate synthase activity. The addition of 2.0 x 10(-5) M MgSO4 x 5H2O into the fermentation medium reduced the Fe2+ ion concentration by counter-acting its deleterious effect on mycelial growth. The magnesium ions also induced a loose-pelleted form of growth (0.6 mm, diameter), reduced the biomass concentration (12.5 g/l) and increased the volumetric productivity of citric acid monohydrate (113.6 +/- 5 g/l).
Hayer, Kimran; Stratford, Malcolm; Archer, David B
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.
Jang, Ja Yeong; Choi, Yong Ho; Shin, Teak Soo; Kim, Tae Hoon; Shin, Kee-Sun; Park, Hae Woong; Kim, Young Ho; Kim, Hun; Choi, Gyung Ja; Jang, Kyoung Soo; Cha, Byeongjin; Kim, In Seon; Myung, Eul Jae
Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s) and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS). Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP) formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10%) and oxalic acid-WP8 (ai 8%), were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate). These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease. PMID:27258452
Ja Yeong Jang
Full Text Available Restricted usage of chemical nematicides has led to development of environmentally safe alternatives. A culture filtrate of Aspergillus niger F22 was highly active against Meloidogyne incognita with marked mortality of second-stage juveniles (J2s and inhibition of egg hatching. The nematicidal component was identified as oxalic acid by organic acid analysis and gas chromatography-mass spectroscopy (GC-MS. Exposure to 2 mmol/L oxalic acid resulted in 100% juvenile mortality at 1 day after treatment and suppressed egg hatching by 95.6% at 7 days after treatment. Oxalic acid showed similar nematicidal activity against M. hapla, but was not highly toxic to Bursaphelenchus xylophilus. The fungus was incubated on solid medium and dried culture was used for preparation of a wettable powder-type (WP formulation as an active ingredient. Two WP formulations, F22-WP10 (ai 10% and oxalic acid-WP8 (ai 8%, were prepared using F22 solid culture and oxalic acid. In a field naturally infested with M. incognita, application of a mixture of F22-WP10 + oxalic acid-WP8 at 1,000- and 500-fold dilutions significantly reduced gall formation on the roots of watermelon plants by 58.8 and 70.7%, respectively, compared to the non-treated control. The disease control efficacy of the mixture of F22-WP10 + oxalic acid-WP8 was significantly higher than that of a chemical nematicide, Sunchungtan (ai 30% fosthiazate. These results suggest that A. niger F22 can be used as a microbial nematicide for the control of root-knot nematode disease.
Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian
Aspergillus niger spores were used as catalyst in the bioconversion of glucose to gluconic acid. Spores produced by solid-state fermentation were treated with 15 different terpenes including monoterpenes and monoterpenoids to permeabilize and inhibit spore germination. It was found that spore membrane permeability is significantly increased by treatment with terpenoids when compared to monoterpenes. Best results were obtained with citral and isonovalal. Studies were carried out to optimize spores concentration (10(7)-10(10) spores/mL), terpene concentrations in the bioconversion medium and time of exposure (1-18 h) needed for permeabilization of spores. Fed-batch production of gluconate was done in a bioreactor with the best conditions [10(9) spores/mL of freeze-thawed spores treated with citral (3% v/v) for 5 h] followed by sequential additions of glucose powder and pH-regulated with a solution containing 2 mol/L of either NaOH or KOH. Bioconversion performance of the spore enzyme was compared with the commercial glucose oxidase at 50, 60, and 70 degrees C. Results showed that the spore enzyme was comparatively stable at 60 degrees C. It was also found that the spores could be reutilized for more than 14 cycles with almost similar reaction rate. Similar biocatalytic activity was rendered by spores even after its storage of 1 year at -20 degrees C. This study provided an experimental evidence of the significant catalytic role played by A. niger spore in bioconversion of glucose to gluconic acid with high yield and stability, giving protection to glucose oxidase.
Gustavo Pagotto Borin
Full Text Available Our dependence on fossil fuel sources and concern about the environment has generated a worldwide interest in establishing new sources of fuel and energy. Thus, the use of ethanol as a fuel is advantageous because it is an inexhaustible energy source and has minimal environmental impact. Currently, Brazil is the world's second largest producer of ethanol, which is produced from sugarcane juice fermentation. However, several studies suggest that Brazil could double its production per hectare by using sugarcane bagasse and straw, known as second-generation (2G bioethanol. Nevertheless, the use of this biomass presents a challenge because the plant cell wall structure, which is composed of complex sugars (cellulose and hemicelluloses, must be broken down into fermentable sugar, such as glucose and xylose. To achieve this goal, several types of hydrolytic enzymes are necessary, and these enzymes represent the majority of the cost associated with 2G bioethanol processing. Reducing the cost of the saccharification process can be achieved via a comprehensive understanding of the hydrolytic mechanisms and enzyme secretion of polysaccharide-hydrolyzing microorganisms. In many natural habitats, several microorganisms degrade lignocellulosic biomass through a set of enzymes that act synergistically. In this study, two fungal species, Aspergillus niger and Trichoderma reesei, were grown on sugarcane biomass with two levels of cell wall complexity, culm in natura and pretreated bagasse. The production of enzymes related to biomass degradation was monitored using secretome analyses after 6, 12 and 24 hours. Concurrently, we analyzed the sugars in the supernatant.Analyzing the concentration of monosaccharides in the supernatant, we observed that both species are able to disassemble the polysaccharides of sugarcane cell walls since 6 hours post-inoculation. The sugars from the polysaccharides such as arabinoxylan and β-glucan (that compose the most external
Gougouli, Maria; Koutsoumanis, Konstantinos P
The growth of Penicillium expansum and Aspergillus niger, isolated from yogurt production environment, was investigated on malt extract agar with pH=4.2 and a(w)=0.997, simulating yogurt, at isothermal conditions ranging from -1.3 to 35 degrees C and from 5 to 42.3 degrees C, respectively. The growth rate (mu) and (apparent) lag time (lambda) of the mycelium growth were modelled as a function of temperature using a Cardinal Model with Inflection (CMI). The results showed that the CMI can describe successfully the effect of temperature on fungal growth within the entire biokinetic range for both isolates. The estimated values of the CMI for mu were T(min)=-5.74 degrees C, T(max)=30.97 degrees C, T(opt)=22.08 degrees C and mu(opt)=0.221 mm/h for P. expansum and T(min)=10.13 degrees C, T(max)=43.13 degrees C, T(opt)=31.44 degrees C, and mu(opt)=0.840 mm/h for A. niger. The cardinal values for lambda were very close to the respective values for mu indicating similar temperature dependence of the growth rate and the lag time of the mycelium growth. The developed models were further validated under fluctuating temperature conditions using various dynamic temperature scenarios. The time-temperature conditions studied included single temperature shifts before or after the end of the lag time and continuous periodic temperature fluctuations. The prediction of growth at changing temperature was based on the assumption that after a temperature shift the growth rate is adopted instantaneously to the new temperature, while the lag time was predicted using a cumulative lag approach. The results showed that when the temperature shifts occurred before the end of the lag, they did not cause any significant additional lag and the observed total lag was very close to the cumulative lag predicted by the model. In experiments with temperature shifts after the end of the lag time, accurate predictions were obtained when the temperature profile included temperatures which were inside the
Del Mundo Dacera, Dominica; Babel, Sandhya
The environmental benefits derived from using citric acid in the removal of heavy metals from contaminated sewage sludge have made it promising as an extracting agent in the chemical extraction process. At present, citric acid is produced commercially by fermentation of sucrose using mutant strains of Aspergillus niger (A. niger), and chemical synthesis. In recent years, various carbohydrates and wastes (such as pineapple wastes) have been considered experimentally, to produce citric acid by A. niger. This study investigated the potential of using A. niger fermented raw liquid from pineapple wastes as a source of citric acid, in extracting chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sewage sludge. Results of the study revealed that metal removal efficiencies varied with pH, forms of metals in sludge and contact time. At pH approaching 4, and contact time of 11 days, A. niger fermented liquid seemed to remove all Cr and Zn while removing 94% of Ni. Moreover, chemical speciation studies revealed that metals which are predominantly in the exchangeable and oxidizable phases seemed to exhibit ease of leachability (e.g., Zn). The by-products of the process such as pineapple pulp and mycelium which are rich in protein, can still be used as animal feed. It can be said therefore that this novel process provides a sustainable way of managing contaminated sewage sludge.
van den Brink, Joost; Maitan-Alfenas, Gabriela Piccolo; Zou, Gen; Wang, Chengshu; Zhou, Zhihua; Guimarães, Valéria Monteze; de Vries, Ronald P
Plant-degrading enzymes can be produced by fungi on abundantly available low-cost plant biomass. However, enzymes sets after growth on complex substrates need to be better understood, especially with emphasis on differences between fungal species and the influence of inhibitory compounds in plant substrates, such as monosaccharides. In this study, Aspergillus niger and Trichoderma reesei were evaluated for the production of enzyme sets after growth on two "second generation" substrates: wheat straw (WS) and sugarcane bagasse (SCB). A. niger and T. reesei produced different sets of (hemi-)cellulolytic enzymes after growth on WS and SCB. This was reflected in an overall strong synergistic effect in releasing sugars during saccharification using A. niger and T. reesei enzyme sets. T. reesei produced less hydrolytic enzymes after growth on non-washed SCB. The sensitivity to non-washed plant substrates was not reduced by using CreA/Cre1 mutants of T. reesei and A. niger with a defective carbon catabolite repression. The importance of removing monosaccharides for producing enzymes was further underlined by the decrease in hydrolytic activities with increased glucose concentrations in WS media. This study showed the importance of removing monosaccharides from the enzyme production media and combining T. reesei and A. niger enzyme sets to improve plant biomass saccharification.
Sarman Oktovianus Gultom
Full Text Available Microalgae harvesting is a labor- and energy-intensive process and new approaches to harvesting microalgae need to be developed in order to decrease the costs. In this study; co-cultivatation of filamentous fungus (Aspergillus niger and microalgae (Chlorella vulgaris to form cell pellets was evaluated under different conditions, including organic carbon source (glucose; glycerol; and sodium acetate concentration; initial concentration of fungal spores and microalgal cells and light. Results showed that 2 g/L of glucose with a 1:300 ratio of fungi to microalgae provided the best culturing conditions for the process to reach >90% of cell harvest efficiency. The results also showed that an organic carbon source was required to sustain the growth of fungi and form the cell pellets. The microalgae/fungi co-cultures at mixotrophic conditions obtained much higher total biomass than pure cultures of each individual strains; indicating the symbiotic relationship between two strains. This can benefit the microbial biofuel production in terms of cell harvest and biomass production.
Samia A. Ahmed
Full Text Available Aspergillus niger β-glucosidase was modified by covalent coupling to periodate activated polysaccharides (glycosylation. The conjugated enzyme to activated starch showed the highest specific activity (128.5 U/mg protein. Compared to the native enzyme, the conjugated form exhibited: a higher optimal reaction temperature, a lower Ea (activation energy, a higher Km (Michaelis constant and Vmax (maximal reaction rate, and improved thermal stability. The calculated t1/2 (half-life values of heat in-activation at 60 °C and 70 °C were 245.7 and 54.5 min respectively, whereas at these temperatures the native enzyme was less stable (t1/2of 200.0 and 49.5 min respectively. The conjugated enzyme retained 32.3 and 29.7%, respectively from its initial activity in presence of 5 mM Sodium Dodecyl Sulphate (SDS and p-Chloro Mercuri Benzoate (p-CMB, while the native enzyme showed a remarkable loss of activity (retained activity 1.61 and 13.7%, respectively. The present work has established the potential of glycosylation to enhance the catalytic properties of β-glucosidase enzyme, making this enzyme potentially feasible for biotechnological applications.
Mariani, D D; Lorda, G; Balatti, A P
In this paper the influence of the amaranth seed meal and the aeration conditions on the alpha-amylase production by Aspergillus niger NRRL 3112 were studied. The assays of selection of culture medium were carried out in a rotary shaker at 250 rpm and 2.5 cm stroke. The aeration conditions were studied in a mechanically stirred fermentor New Brunswick type. A concentration of alpha-amylase of 2750 U.Dun/ml was achieved at 120 h with a dry weight of 8.0 g/l, using a base medium with 5.0 g/l Amaranthus cruentus seed meal. In the experiment performed in a New Brunswick fermentor, the highest value was 2806 U.Dun/ml. This result was obtained after 120 h, operating at 300 rpm and an airflow of 1 l/l. min. in a limited dissolved oxygen concentration. It was determined that the increase in the agitation rate was not favorable to the enzyme production, despite that an increase was verified in the dissolved oxygen. The morphology of the microorganism, in long and ramified hyphae, was the critical factor to obtain higher levels of alpha-amylase.
Ahmed I. El-Batal
Full Text Available In this study, Aspergillus niger ADM110 fungi was gamma irradiated to produce lipase enzyme and then immobilized onto magnetic barium ferrite nanoparticles (BFN for biodiesel production. BFN were prepared by the citrate sol-gel auto-combustion method and characterized by transmission electron microscopy (TEM, X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy with energy dispersive analysis of X-ray (SEM/EDAX analysis. The activities of free and immobilized lipase were measured at various pH and temperature values. The results indicate that BFN–Lipase (5% can be reused in biodiesel production without any treatment with 17% loss of activity after five cycles and 66% loss in activity in the sixth cycle. The optimum reaction conditions for biodiesel production from waste cooking oil (WCO using lipase immobilized onto BFN as a catalyst were 45 °C, 4 h and 400 rpm. Acid values of WCO and fatty acid methyl esters (FAMEs were 1.90 and 0.182 (mg KOH/g oil, respectively. The measured flash point, calorific value and cetane number were 188 °C, 43.1 MJ/Kg and 59.5, respectively. The cloud point (−3 °C, pour point (−9 °C, water content (0.091% and sulfur content (0.050%, were estimated as well.
Antier, P; Minjares, A; Roussos, S; Viniegra-González, G
The aim of this paper is to review and study a new approach for improving strains of Aspergillus niger specially adapted to produce pectinases by Solid State Fermentation (SSF) with materials having low levels of water activity (a(w)), i.e., coffee pulp. Special emphasis is placed on the use of two antimetabolic compounds: 2-deoxy-glucose (DG) and 2,4-dinitro-phenol (DNP) combined with a water depressant (ethylene glycol = EG) in order to put strong selection pressures on UV treated spores from parental strain C28B25 isolated from a coffee plantation. Such a strain was found to be DG sensitive. Results suggested the existence of a reciprocal relation between adaptation of isolated strains to SSF or to Submerged Fermentation (SmF) systems. Preliminary physiological analysis of isolated strains showed that at least some few initially DG resistant mutants could revert to DG sensitive phenotype but conserving increased pectinase production. Also it was found that phenotype for DNP resistance could be associated to changes of DG resistance. Finally, it was found that low levels of a(w) produced by adding 15% EG to agar plates, were a significant selection factor for strains well adapted to SSF system.
Taskin, Mesut; Tasar, Gani Erhan; Incekara, Umit
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.
Full Text Available 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 K M = 54 µmol l-1 and k cat = 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(1,2,4,5,6P5, D-Ins(1,2,5,6P4, D-Ins(1,2,6P3, D-Ins(1,2P2 to finally Ins(2P.
Montserrat, Veronica; Bruins, Maaike J; Edens, Luppo; Koning, Frits
Celiac disease (CD) is caused by intolerance to gluten. Oral supplementation with enzymes like Aspergillus niger propyl-endoprotease (AN-PEP), which can hydrolyse gluten, has been proposed to prevent the harmful effects of ingestion of gluten. The influence of meal composition on AN-PEP activity was investigated using an in vitro model that simulates stomach-like conditions. AN-PEP optimal dosage was 20 proline protease units (PPU)/g gluten. The addition of a carbonated drink strongly enhanced AN-PEP activity because of its acidifying effect. While fat did not affect gluten degradation by AN-PEP, the presence of food proteins slowed down gluten detoxification. Moreover, raw gluten was degraded more efficiently by AN-PEP than baked gluten. We conclude that the meal composition influences the amount of AN-PEP needed for gluten elimination. Therefore, AN-PEP should not be used to replace a gluten free diet, but rather to support digestion of occasional and/or inadvertent gluten consumption.
Ibrahim Che Omar
Full Text Available Isolate USM A1 I which was identified to be Aspergillus niger was selected as a potential producer of xylanase via a solid state fermentation system (SSF using palm kernel cake (PKC as substrate. The modification of the physical conditions of the SSF system indicated that the xylanase activity was 23.97 U/g PKC at the moisture ratio of 1:0.75 of PKC: moistening agent with the inoculum size of 1¥104 spores/ml and cultivated at the ambient temperature (28±3ºC. The supplementation of additional carbon and nitrogen sources in the PKC medium could enhance enzyme productivity. The maximum production of xylanase and growth obtained with the supplementation of xylose at 0.75% (w/w were 25.40 U/g and 1.69 mg glucosamine/ g PKC. Moreover, the presence of NaNO3 at 0.075% (w/w as additional nitrogen source further enhanced xylanase production to 33.99 U/g PKC although the growth remained unchanged at about 1.67 mg glucosa- mine/g PKC. The optimized conditions showed an increased xylanase production by 157% compared to before the optimization of the SSF system. The xylanase productivity was 23.12 U/mg glucosamine after optimization and 11.72 U/mg glucosamine before optimization.
Jernejc, Katarina; Legisa, Matic
In the presence of copper significant induction of citric acid overflow was observed, while concomitantly lower levels of total lipids were detected in the cells. Its effect was more obvious in a medium with magnesium as sole divalent metal ions, while in a medium with magnesium and manganese the addition of copper had a less pronounced effect. Since the malic enzyme was recognised as a supplier of reducing power in the form of reduced nicotinamide adenine dinucleotide phosphate for lipid biosynthesis, its kinetic parameters with regard to different concentrations of metal ions were investigated. Some inhibition was found with Fe(2+) and Zn(2+), while Cu(2+) ions in a concentration of 0.1 mM completely abolished malic enzyme activity. The same metal ions proportionally reduced the levels of total lipids in Aspergillus niger cells. A strong competitive inhibition of the enzyme by Cu(2+) was observed. It seemed that copper competes with Mg(2+) and Mn(2+) for the same binding site on the protein.
Full Text Available Extracellular tannase and gallic acid were produced optimally under submerged fermentation at 37 0C, 72 h, pH 5.0, 10 %(v/v inoculum and 4 %(w/v of the agroresidue pomegranate rind (PR powder by an Aspergillus niger isolate. Tannic acid (1 % stimulated the enzyme production by 245.9 % while with 0.5 % glucose, increase was marginal. Tannase production was inhibited by gallic acid and nitrogen sources such as NH4NO3, NH4Cl, KNO3, asparatic acid, urea and EDTA. The partially purified enzyme showed temperature and pH optima of 35 0C and 6.2 respectively which shifted to 40 0C and 5.8 on immobilization in alginate beads. Activity of the enzyme was inhibited by Zn+2, Ca+, Mn+2, Mg+2, Ba+2and Ag+. The immobilized enzyme removed 68.8 % tannin from juice of aonla/myrobalan (Phyllanthus emblica, a tropical fruit, rich in vitamin C and other essential nutrients. The enzymatic treatment of the juice with minimum reduction in vitamin C is encouraging as non enzymatic treatments of myrobalan juice results in vitamin C removal.
Sánchez-Marroquín, A.; Carreño, R.; Ledezma, M.
Citric acid yields of 98.7% (sugar consumption basis) were reached in shaker flasks with mutant UV-ET-71-15 of Aspergillus niger in a resin-treated sucrose medium of the following composition (g/100 ml): sucrose, 14.0; NH4NO3, 0.20; KH2PO4, 0.10; MgSO4·7H2O, 0.025; and (mg/liter): FeSO4, 0.15 to 0.75; ZnSO4, 0.10; and CuSO4, 0.01. Yields of 75% were obtained in medium with resin-treated clarified syrup and 68% with ferrocyanide-treated blackstrap molasses. Optimal conditions included selection of appropriate pellets as inoculum at 3%, pH of 4.5, temperature at 30 C, agitation at 250 rev/min, and fermentation time of 8 days. The mutant tolerated high concentrations of trace elements. PMID:5492439
Esawy, Mona A; Gamal, Amira A; Kamel, Zeinat; Ismail, Abdel-Mohsen S; Abdel-Fattah, Ahmed F
The Aspergillus niger NRC1ami pectinase was evaluated according to its hydrolysis efficiency of dry untreated orange peels (UOP), HCl-treated orange peels and NaOH-treated orange peels (HOP and NOP). Pectinase was entrapped in polyvinyl alcohol (PVA) sponge and the optimum pH and temperature of the free and immobilized enzymes were shifted from 4, 40 °C to 6, 50 °C respectively. The study of pH stability of free and immobilized pectinase showed that the immobilization process protected the enzyme strongly from severe alkaline pHs. The immobilization process improved the enzyme thermal stability to great instant. The unique feature of the immobilization process is its ability to solve the orange juice haze problem completely. Immobilized enzyme was reused 12 times in orange juice clarification with 9% activity loss from the original activity. Maximum reaction rate (V(max)) and Michaelis-Menten constant (K(m)) of the partially purified form were significantly changed after immobilization.
Full Text Available Buildings are a vital component in a human’s daily life. It provides shelter from the environment, weather and animals. Mold growth within the building might be caused by the moisture problems which directly act on it such as water leaks or indirect factor such as high humidity levels. This growth causes esthetic problems and deterioration of its wall coatings. Spores from the fungi also cause health problems to humans. The fungus species studied in this research is Aspergillus niger. The material is made of wood and its finishing is thick wallpaper, thin wallpaper, acrylic paint and glycerol based paint. ASTMD5590-00 standard was used to evaluate fungal growth and to determine if non antifungal agent was effective in inhibiting the amount of fungal growth on four types of wall finishing used on wooden walls. This research was conducted without using any antifungal agent. Highest percentage of growth of the fungi was found on acrylic paint, followed by glycerol based paint and thin wallpaper. Thick wall paper shows the least growth of fungi. The maximum growth is visible on day 12 which is more than 60% by all the wall finishing.
Megawati, Dewi, Rizna Triana; Mulyani, Hanny; Maryani, Faiza; Lotullung, Puspa Dewi N.; Minarti
During the research for bioactive secondary metabolites from microorganisms, the terestrial fungi Aspergillus niger GTS01-4 has been investigated for the evaluation of antimicrobial and cytotoxic activities using brine shrimp (Artemia salina) lethality test and MCF-7 cell line. Further chromatographic separation and purification of myselium extract resulted in the isolation identified as rubrofusarin (1). The structure elucidation of isolated compound was performed using 1D-NMR, and LCMS. Furthermore, the cytotoxicity of rubrofusarin (1) was evaluated and resulted with IC50 of 11.51 µg/mL against MCF-7 and LC50 of 368.11 µg/mL against brine shrimp, respectively. However, rubrofusarin (1) showed moderate activity against E. coli, S. aureus, and B. subtilis compared to standard antibiotic, streptomycin. The average zone of inhibition was ranged from 6 to 8 mm at a concentration of 100 µg/disc. These results suggest that rubrofusarin could be a potential candidate in the field of anticancer drug discovery from terrestrial fungi.
Biswas, Supratim; Samanta, Saikat; Dey, Rajib; Mukherjee, Siddhartha; Banerjee, Pataki C.
Leaching of nickel and cobalt from two physical grades (S1, 125-190 μm, coarser and S3, 53-75 μm, finer) of chromite overburden was achieved by treating the overburden (2% pulp density) with 21-d culture filtrate of an Aspergillus niger strain grown in sucrose medium. Metal dissolution increases with ore roasting at 600°C and decreasing particle size due to the alteration of microstructural properties involving the conversion of goethite to hematite and the increase in surface area and porosity as evident from X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (DT-TGA), and field emission scanning electron microscopy (FESEM). About 65% Ni and 59% Co were recovered from the roasted S3 ore employing bioleaching against 26.87% Ni and 31.3% Co using an equivalent amount of synthetic oxalic acid under identical conditions. The results suggest that other fungal metabolites in the culture filtrate played a positive role in the bioleaching process, making it an efficient green approach in Ni and Co recovery from lateritic chromite overburden.
Georgi Todorov Dobrev
Full Text Available An extracellular endoglucanase was isolated from the culture liquid of xylanase producing strain Aspergillus niger B03. The enzyme was purified to a homogenous form, using consecutive ultrafiltration, anion exchange chromatography, and gel filtration. Endoglucanase was a monomer protein with a molecular weight of 26,900 Da determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 28,800 Da determined by gel filtration. The optimal pH and temperature values for the enzyme action were 3.5 and 65ºC respectively. Endoglucanase was stable at 40ºC, pH 3.0 for 210 min. The substrate specificity of the enzyme was determined with carboxymethyl cellulose, filter paper, and different glycosides. Endoglucanase displayed maximum activity in the case of carboxymethyl cellulose, with a Km value of 21.01 mg/mL. The substrate specificity and the pattern of substrate degradation suggested that the enzyme is an endoglucanase. Endoglucanase showed a synergism with endoxylanase in corn cobs hydrolysis.
LIU Yun-guo; FAN Ting; ZENG Guang-ming; LI Xin; TONG Qing; YE Fei; ZHOU Ming; XU Wei-hua; HUANG Yu-e
The potential of living Aspergillus niger to remove cadmium and zinc from aqueous solution was investigated. Effects of pH, initial concentration, contact time, temperature and agitation rate on the biosorption of Cd(Ⅱ) and Zn(Ⅱ) ions were studied. The optimum adsorption pH value for Cd(Ⅱ) and Zn(Ⅱ) were 4.0 and 6.0. The best temperature and agitation rate were in the range of 25-30 ℃ and 120 r/min for all metal ions. Under the optimal conditions, the maximum uptake capacities of Cd(Ⅱ) and Zn( Ⅱ ) ions are 15.50 mg/g and 23.70 mg/g at initial concentrations of 75 mg/L and 150 mg/L, respectively. Biosorption equilibrium is established within 24 h for cadmium and zinc ions. The adsorption data provide an excellent fit to Langmuir isotherm model. The results of the kinetic studies show that the rate of adsorption follows the pseudo-second order kinetics.
Auta, Helen Shnada; Abidoye, Khadijat Toyin; Tahir, Hauwa; Ibrahim, Aliyu Dabai; Aransiola, Sesan Abiodun
The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5-dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine-acetic anhydride methods. The studies revealed that production parameters (pH, inoculum size, substrate concentration, incubation temperature, and fermentation period) had profound effect on the amount of citric acid produced. The maximum yield was obtained at the pH of 2 with citric acid of 1.15 g/L and reducing sugar content of 0.541 mMol(-1), 3% vegetative inoculum size with citric acid yield of 0.53 g/L and reducing sugar content of 8.87 mMol(-1), 2% of the substrate concentration with citric acid yield of 0.83 g/L and reducing sugar content of 9.36 mMol(-1), incubation temperature of 55°C with citric acid yield of 0.62 g/L and reducing sugar content of 8.37 mMol(-1), and fermentation period of 5 days with citric acid yield of 0.61 g/L and reducing sugar content of 3.70 mMol(-1). The results of this study are encouraging and suggest that Parkia biglobosa pulp can be harnessed at low concentration for large scale citric acid production.
Ahmed Al-Tammar Khadijah
Full Text Available Cutin hydrolase (EC 184.108.40.206, an extracellular polyesterase found in pollens, bacteria and fungi, is an efficient catalyst that exhibits hydrolytic activity on a variety of water-soluble esters, synthetic fibers, plastics and triglycerides. Thus, cutinase can be used in various applications such as ester synthesis, bio-scouring, food and detergent industries. Ancut2 is one of five genes encoding cutinases present in the Aspergillus niger ATCC 10574 genome. The cDNA of Ancut2 comprising of an open reading frame of 816 bp encoding a protein of 271 amino acid residues, was isolated and expressed in Pichia pastoris. The partially purified recombinant cutinase exhibited a molecular mass of approximately 40 kDa. The enzyme showed highest activity at 40°C with a preference for acidic pH (5.0-6.0. AnCUT2 showed hydrolytic activity towards various p-nitrophenyl esters with preference towards shorter chain esters such as p-nitrophenyl butyrate (C4. Scanning Electron Microscopy demonstrated that AnCUT2 was capable of modifying surfaces of synthetic polycaprolactone and polyethylene terephthalate plastics. The properties of this enzyme suggest that it may be applied in synthetic fiber modification and fruit processing industries.
Cinthya Babá Barroso
Full Text Available The present study deals with the effect of increased concentrations of alcohols (methanol and ethanol on the solubilization of FePO4 and CaHPO4 by Aspergillus niger. The efficiency of solubilization (ES of inorganic phosphates, fungal growth, acid production and pH variation were determined. The concentrations of alcohols that most favored the solubilization of phosphates were 4% methanol and 3% ethanol. The ES of phosphates by the fungus in media containing methanol ranged from 11-96% and 0.4-87% for ethanol. The stimulation or inhibition of solubilization was dependent on greater or lesser fungus growth, acid production and decreased pH. These responses were supported by the correlation between the amount of phosphate dissolved and fungal growth (0.630** to 0.831**, the production of acids (0.529* to 0.989** and a decrease in pH (-0.755** to -0.962**. Thus, the addition of alcohols facilitated insoluble phosphates dissolution during the fungus growth.
Full Text Available An experiment has been conducted to determine the effect of type of packaging and time of storage on fermented palm oil sludge. The palm oil sludge was fermented with Aspergillus niger, dried, kept in differentpackaging materials (plastic bags, feed bag, and paper bag and stored under room temperatures for 12 weeks. The experiment was assigned in a split plot design (3x7. The parameters measured were water content, crude protein, soluble nitrogen, true protein, in vitro dry matter (IVDMD and true protein digestibilities (IVTPD, total in vitro digestible protein, and the activities of mannanase and cellulase. Results showed that fermented palm oil sludge stored for 12 weeks increased the water content, decreased the true protein and fiber contents, and also reduced the activity of mannanase and cellulase and in vitro dry matter digestibility but no changes on the crude protein content, protein digestibility, and total digestible protein. It was concluded that fermented palm oil sludge should be kept in feed bag under room temperature if to be stored for 12 weeks.
Zheng, Xianliang; Fang, Bo; Han, Dongfei; Yang, Wenxia; Qi, Feifei; Chen, Hui; Li, Shengying
α-Galactosidases are broadly used in feed, food, chemical, pulp, and pharmaceutical industries. However, there lacks a satisfactory microbial cell factory that is able to produce α-galactosidases efficiently and cost-effectively to date, which prevents these important enzymes from greater application. In this study, the secretory expression of an Aspergillus niger α-galactosidase (AGA) in Pichia pastoris was systematically investigated. Through codon optimization, signal peptide replacement, comparative selection of host strain, and saturation mutagenesis of the P1’ residue of Kex2 protease cleavage site for efficient signal peptide removal, a mutant P. pastoris KM71H (Muts) strain of AGA-I with the specific P1’ site substitution (Glu to Ile) demonstrated remarkable extracellular α-galactosidase activity of 1299 U/ml upon a 72 h methanol induction in 2.0 L fermenter. The engineered yeast strain AGA-I demonstrated approximately 12-fold higher extracellular activity compared to the initial P. pastoris strain. To the best of our knowledge, this represents the highest yield and productivity of a secreted α-galactosidase in P. pastoris, thus holding great potential for industrial application. PMID:27548309
Ahmad, Zulfiqar; Butt, Masood Sadiq; Ahmed, Anwaar; Riaz, Muhammad; Sabir, Syed Mubashar; Farooq, Umar; Rehman, Fazal Ur
The present study was conducted to investigate the impact of various treatments of xylanase produced by Aspergillus niger applied in bread making processes like during tempering of wheat kernels and dough mixing on the dough quality characteristics i.e. dryness, stiffness, elasticity, extensibility, coherency and bread quality parameters i.e. volume, specific volume, density, moisture retention and sensory attributes. Different doses (200, 400, 600, 800 and 1,000 IU) of purified enzyme were applied to 1 kg of wheat grains during tempering and 1 kg of flour (straight grade flour) during mixing of dough in parallel. The samples of wheat kernels were agitated at different intervals for uniformity in tempering. After milling and dough making of both types of flour (having enzyme treatment during tempering and flour mixing) showed improved dough characteristics but the improvement was more prominent in the samples receiving enzyme treatment during tempering. Moreover, xylanase decreased dryness and stiffness of the dough whereas, resulted in increased elasticity, extensibility and coherency and increase in volume & decrease in bread density. Xylanase treatments also resulted in higher moisture retention and improvement of sensory attributes of bread. From the results, it is concluded that dough characteristics and bread quality improved significantly in response to enzyme treatments during tempering as compared to application during mixing.
Full Text Available Polygalacturonase was produced from Aspergillus niger BC 23 which was isolated from spoiled Irvingia gabonensis fruit. The influence of carbon substrates on enzyme production showed that the medium containing sucrose produced a maximum enzyme yield of 38.5 U/mg protein after 72 h. Enzyme productivity in this medium was much higher than in the medium that contained only citrus pectin as the sole carbon source. Medium containing yeast extract as a nitrogen source caused the production of specific enzyme activity of 31.2 U/mg protein. Results on the effect of metal ions on enzyme activity showed that Ca2+ gave a percent relative activity of 214% in comparison to the native enzyme activity. The enzyme showed maximum activity in slight acid and neutral pH media with optimal activity at pH 4.0. Temperature activity profile of the enzyme showed best activity at a temperature of 35ºC. Dried fruit peels were tested for their abilities to support enzyme production in a media devoid of citrus pectin. The best enzyme productivity of 102.3 U/mg protein was achieved after 72 h in the medium containing orange peel and this level was much higher than that achieved when pure carbon sources or citrus pectin alone were used for enzyme production.
Hahonou, Eric Komlavi
The chapter provides knowledge about the role of non-state actors in security provision in Niger. It argues that it is of upmost importance to dig into the causes of ongoing armed conflicts and volatile situations. It points out the long-term decline of public service provision (including the rol...... played by police force in protection rackets) and the growing gap between ruling elites and ordinary citizens. These developments have paved the way for the rise of alternative security providers, including Islamic reformist movements.......The chapter provides knowledge about the role of non-state actors in security provision in Niger. It argues that it is of upmost importance to dig into the causes of ongoing armed conflicts and volatile situations. It points out the long-term decline of public service provision (including the role...
Full Text Available Abstract 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
Juge, N; Svensson, B; Williamson, G
Efficient production of recombinant barley alpha-amylase has been achieved in Aspergillus niger. The cDNA encoding alpha-amylase isozyme 1 (AMY1) and its signal peptide was placed under the control of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpd) promoter and the A. nidulans trpC gene terminator. Secretion yields up to 60 mg/l were obtained in media optimised for alpha-amylase activity and low protease activity. The recombinant AMY1 (reAMY1) was purified to homogeneity and found to be identical to native barley AMY1 with respect to size, pI, and immunoreactivity. N-terminal sequence analysis of the recombinant protein indicated that the endogenous plant signal peptide is correctly processed in A. niger. Electrospray ionisation/mass spectrometry gave a molecular mass for the dominant form of 44,960 Da, in accordance with the loss of the LQRS C-terminal residues; glycosylation apparently did not occur. The activities of recombinant and native barley alpha-amylases are very similar towards insoluble and soluble starch as well as 2-chloro-4-nitrophenol beta-D-maltoheptaoside and amylose (degree of polymerisation = 17). Barley alpha-amylase is the first plant protein efficiently secreted and correctly processed by A. niger using its own signal sequence.
Agarwal, Pragati; Pareek, Nidhi; Dubey, Swati; Singh, Jyoti; Singh, R P
L-DOPA (3,4-dihydroxyphenyl-L-alanine), an amino acid derivative is the most widely used drug of choice for the treatment of Parkinson's disease and other neurologic injuries. The present study deals with the elevated biochemical transformation of L-tyrosine to L-DOPA by Aspergillus niger PA2, a potent tyrosinase producer, isolated from decomposed food wastes. This appears to be the first report on A. niger as a notable extracellular tyrosinase producer. The extracellular tyrosinase activity produced remarkably higher levels of L-DOPA, i.e. 2.44 mg mL(-1) when the media was supplemented with 5 mg mL(-1) L-tyrosine. The optimum pH for tyrosinase production was 6.0, with the maximal L-DOPA production at the same pH. The product thus produced was analyzed by thin-layer chromatography, UV spectroscopy, high-performance liquid chromatography and Fourier transform infrared spectroscopy, that had denoted this to be L-DOPA. Kinetic parameters viz. Y p/s, Q s and Q p had further indicated the notable levels of production. Thus, Aspergillus niger PA2 could be a promising resource and may be further exploited for large-scale production of L-DOPA.
Kobayashi, Keiichi; Hattori, Takasumi; Honda, Yuki; Kirimura, Kohtaro
Methylcitrate synthase (EC 220.127.116.11; MCS) is a key enzyme of the methylcitric acid cycle localized in the mitochondria of eukaryotic cells and related to propionic acid metabolism. In this study, cloning of the gene mcsA encoding MCS and heterologous expression of it in Escherichia coli were performed for functional analysis of the MCS of citric acid-producing Aspergillus niger WU-2223L. Only one copy of mcsA (1,495 bp) exists in the A. niger WU-2223L chromosome. It encodes a 51-kDa polypeptide consisting of 465 amino acids containing mitochondrial targeting signal peptides. Purified recombinant MCS showed not only MCS activity (27.6 U/mg) but also citrate synthase (EC 18.104.22.168; CS) activity (26.8 U/mg). For functional analysis of MCS, mcsA disruptant strain DMCS-1, derived from A. niger WU-2223L, was constructed. Although A. niger WU-2223L showed growth on propionate as sole carbon source, DMCS-1 showed no growth. These results suggest that MCS is an essential enzyme in propionic acid metabolism, and that the methylcitric acid cycle operates functionally in A. niger WU-2223L. To determine whether MCS makes a contribution to citric acid production, citric acid production tests on DMCS-1 were performed. The amount of citric acid produced from glucose consumed by DMCS-1 in citric acid production medium over 12 d of cultivation was on the same level to that by WU-2223L. Thus it was found that MCS made no contribution to citric acid production from glucose in A. niger WU-2223L, although MCS showed CS activity.
HIDROLISIS ENZIMATIK MINYAK IKAN UNTUK PRODUKSI ASAM LEMAK OMEGA-3 MENGGUNAKAN LIPASE DARI Aspergillus niger [Enzymatic Hydrolysis of Fish Oil for Production of Omega-3 Fatty Acids Using Lipase Derived from Aspergillus niger
Fish oil is the source of important fatty-acid, especially polyunsaturated fatty acid (PUFA) omega-3, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Lipase catalysis activity of Aspergillus niger is low when it is used in fish oil hydrolysis. The activity of the lipase can be increased by adding organic solvent such as hexane into the media. This research aimed to determine temperature, pH and amount of water which produce the highest degree of hydrolysis of fish oil in t...
Bansal, Namita; Janveja, Chetna; Tewari, Rupinder; Soni, Raman; Soni, Sanjeev Kumar
Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 ± 20.1 U/g, FPase 101.1 ± 3.5 U/g and β-glucosidase 99 ± 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, β-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %.
Ushasree, Mrudula Vasudevan; Vidya, Jalaja; Pandey, Ashok
Microbial phytase, a widely used animal feed enzyme, needs to be active and stable in the acidic milieu for better performance in the monogastric gut. Aspergillus niger phytases exhibit an activity dip in the pH range from 3.0 to 3.5. Replacement of amino acids, which changed the pKa of catalytic residues H82 and D362, resulted in alteration of the pH profile of a thermostable phytase from A. niger NII 08121. Substitution P212H in the protein loop at 14 Å distance to the active site amended the pH optimum from 2.5 to pH 3.2 nevertheless with a decrease in thermostability than the wild enzyme. This study described the utility of amino acid replacements based on pKa shifts of catalytic acid/base to modulate the pH profile of phytases.
Benghazi, Lamiae; Record, Eric; Suárez, Antonio; Gomez-Vidal, José A; Martínez, José; de la Rubia, Teresa
We investigated the expression of Phanerochaete flavido-alba laccase gene in Aspergillus niger and the physical and biochemical properties of the recombinant enzyme (rLac-LPFA) in order to test it for synthetic dye biotransformation. A. niger was able to produce high levels of active recombinant enzyme (30 mgL(-1)), whose identity was further confirmed by immunodetection using Western blot analysis and N-terminal sequencing. Interestingly, rLac-LPFA exhibited an improved stability at pH (2-9) and organic solvents tested. Furthermore, the percentage of decoloration and biotransformation of synthetic textile dyes, Remazol Brilliant Blue R (RBBR) and Acid Red 299 (NY1), was higher than for the native enzyme. Its high production, simple purification, high activity, stability and ability to transform textile dyes make rLac-LPFA a good candidate for industrial applications.
Ikeda, Yuko; Park, Enock Y; Okuda, Naoyuki
Gluconic acid production was investigated using an enzymatic hydrolysate of waste office automation paper in a culture of Aspergillus niger. In repeated batch cultures using flasks, saccharified solution medium (SM) did not show any inhibitory effects on gluconic acid production compared to glucose medium (GM). The average gluconic acid yields were 92% (SM) and 80% (GM). In repeated batch cultures using SM in a turbine blade reactor (TBR), the gluconic acid yields were 60% (SM) and 67% (GM) with 80-100 g/l of gluconic acid. When pure oxygen was supplied the production rate increased to four times higher than when supplying air. Remarkable differences in the morphology of A. niger and dry cell weight between SM and GM were observed. The difference in morphology may have caused a reduction of oxygen transfer, resulting in a decrease in gluconic acid production rate in SM.
Vinícius D'Arcadia Cruz
Full Text Available Aspergillus niger - 245, a strain isolated from soil samples showed good β-fructosidase activity when inoculated in medium formulated with dahlia extract tubers. The enzyme was purified by precipitation in ammonium sulphate and percolated in DEAE-Sephadex A-50 and CM-cellulose columns, witch showed a single peack in all the purification steps, maintaining the I/S ratio between 0.32 to, 0.39. Optimum pH for inulinase activity (I was between 4.0 - 4.5 and for invertase activity (S between 2.5 and 5.0. The optimum temperature was 60O.C for both activities and no loss in activity was observed when it was maintained at this temperature for 30 min. The Km value was 1.44 and 5.0, respectively, for I and S and Vm value 10.48 and 30.55, respectively. The I activity was strongly inhibited by Hg2+ and Ag+ and 2 x 10-3 M of glucose, but not by fructose at the same concentration. The enzyme showed an exo-action mechanism, acting on the inulin of different origins. In assay conditions total hydrolysis of all the frutans was obtained, although it has shown larger activity on the chicory inulin than that one from artichoke Jerusalem and dahlia, in the first 30 min. The obtained results suggested that the enzyme presented good potential for industrial application in the preparing the fructose syrupsAspergillus niger - 245, isolado do solo mostrou boa atividade de b-frutosidase meio formulado com extrato de tubérculos de dahlia. A enzima foi purificada por precipitação em sulfato de amônia e percolada em colunas de DEAE-Sephadex A-50 e CM-celulose, produzindo um único pico em todas as fases de purificação e mantendo a relação I/S entre 0,32 a 0,39. O pH ótimo para a atividade de inulinase (I foi encontrado entre 4,0 - 4.5 e para a atividade de invertase (S em 2,5 e 5,0. A temperatura ótima foi de 60O.C para ambas as atividades e nenhuma perda foi observada quando mantida nesta temperatura por 30 min. Os valores de Km foram de 1,44 e 5
Ana Paula Manera
Full Text Available Amyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd estimated at 133.0 U mL-1 and 15.4 U mL-1, respectively. From the adjustment of the kinetic curves using the fourth-order Runge-Kutta algorithm, the adsorption (k1 and desorption (k2 constants were obtained through optimization by the least square procedure, and the values calculated were 2.4x10-3 mL U-1 min-1 for k1 and 0.037 min-1 for k2 .A enzima amiloglicosidase foi produzida por Aspergillus niger NRRL 3122 através de fermentação em estado sólido, tendo como substrato farelo de arroz desengordurado. Os efeitos dos parâmetros de processo (pH e temperatura no coeficiente de partição no equilíbrio, para o sistema amiloglicosidase - resina DEAE-celulose foram investigados, com o objetivo de se obter as melhores condições para um posterior processo de purificação. Os maiores coeficientes de partição foram obtidos usando tampão Tris-HCl 0,025M pH 8,0 e 25°C. Determinadas as condições que forneceram o maior coeficiente de partição obteve-se a isoterma que melhor descrevia o processo de adsorção de amiloglicosidase. Foi verificado que adsorção pode ser bem descrita pela equação de Langmuir e os valores de Qm e Kd foram estimados em 133,0 U mL-1 e 15,4 U mL-1 respectivamente. A
Yao-xing XU; Yan-li LI; Shao-chun XU; Yong LIU; Xin WANG; Jiang-wu TANG
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 sig-nificant variable, which included urea, Na2CO3 and MgSO4. Subsequently a second-order polynomial was determined by mul-tiple regression analysis. The optimum values of the critical components for maximum xylanase production were obtained as follows: x1 (urea)=0.163 (41.63 g/L), x2 (Na2CO3)=-1.68 (2.64 g/L), x3 (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.
Full Text Available This study aimed to characterize and investigate, for the first time, the treatment of real colored wastewaters from the artisanal dyeing of the typical Tunisian hat Chechia, using a newly isolated fungal strain. This textile effluent was a mixture called Mix of colored wastewaters from the three main types of Chechia. The major pollutant of the Mix was the toxic Azo dye Amaranth Acid or Acid Red 27. The fungal strain that made the cleanup was discovered in a Chechia dyeing wastewater’s container and identified by ITS rDNA gene sequencing. This isolated Aspergillus niger showed interesting performances on the demonstration of Chechia wastewater’s biodegradation in batch cultures. In order to understand the effect of agitation, Mix dilution and inoculum size on decolourisation and pollution removal, a full factorial experimental design 23 was set up. At the optimal conditions which were 20% inoculum size, 25% Chechia Mix dilution and an agitation of 100 rpm, Aspergillus niger was able to remove color as high as 70.18±2.84% at an initial dye concentration of 1346.6±0.01 mg/L, and to reduce COD to 74.17±14.52% at an initial COD of 4157±422 mg/L. FT-IR spectra analysis confirmed the decolourisation by biodegradation and transformation of the dyes. The treatment by the isolated Aspergillus niger could be successfully applied as a sustainable method to solve one of handicraft dyeing plants environmental management issues.
Frébort, I; Matsushita, K; Toyama, H; Lemr, K; Yamada, M; Adachi, O
Crude extract of Aspergillus niger AKU 3302 mycelia incubated with methylamine showed a single amine oxidase activity band in a developed polyacrylamide gel that weakly cross-reacted with the antibody against a copper/topa quinone-containing amine oxidase (AO-II) from the same strain induced by n-butylamine. Since the organism cannot grow on methylamine and the already known quinoprotein amine oxidases of the organism cannot catalyze oxidation of methylamine, the organism was forced to produce another enzyme that could oxidize methylamine when the mycelia were incubated with methylamine. The enzyme was separated and purified from the already known two quinoprotein amine oxidases formed in the same mycelia. The purified enzyme showed a sharp symmetric sedimentation peak in analytical ultracentrifugation showing S20,w0 of 6.5s. The molecular mass of 133 kDa estimated by gel chromatography and 66.6 kDa found by SDS-PAGE confirmed the dimeric structure of the enzyme. The purified enzyme was pink in color with an absorption maximum at 494 nm. The enzyme readily oxidized methylamine, n-hexylamine, and n-butylamine, but not benzylamine, histamine, or tyramine, favorite substrates for the already known two quinoprotein amine oxidases. Inactivation by carbonyl reagents and copper chelators suggested the presence of a copper/topa quinone cofactor. Spectrophotometric titration by p-nitrophenylhydrazine showed one reactive carbonyl group per subunit and redox-cyclic quinone staining confirmed the presence of a quinone cofactor. pH-dependent shift of the absorption spectrum of the enzyme-p-nitrophenylhydrazone (469 nm at neutral to 577 nm at alkaline pH) supported the identity of the cofactor with topaquinone. Nothern blot analysis indicated that the methylamine oxidase encoding gene is largely different from the already known amine oxidase in the organism.
Paulo S. Monteiro
Full Text Available An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE, indicating that it may be a dimer. It presented an optimum temperature of 60 °C and optimum pH of 2.0. The KM for sodium phytate hydrolysis was 30.9 mM, while the kcat and kcat/KM were 1.46 ×105 s−1 and 4.7 × 106s−1.M−1, respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg2+, Cd2+, K+ and Ca2+, and it was drastically inhibited by F−. The enzyme displayed high thermostability, retaining more than 90% activity at 60 °C during 120 h and displayed a t1/2 of 94.5 h and 6.2 h at 70 °C and 80 °C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 μmol phosphate/mL after 2.5 h of treatment.
Monteiro, Paulo S; Guimarães, Valéria M; de Melo, Ricardo R; de Rezende, Sebastião T
An Aspergillus niger UFV-1 phytase was characterized and made available for industrial application. The enzyme was purified via ultrafiltration followed by acid precipitation, ion exchange and gel filtration chromatography. This protein exhibited a molecular mass of 161 kDa in gel filtration and 81 kDa in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), indicating that it may be a dimer. It presented an optimum temperature of 60 °C and optimum pH of 2.0. The K M for sodium phytate hydrolysis was 30.9 mM, while the k cat and k cat / K M were 1.46 ×10 (5) s (-1) and 4.7 × 10 (6) s (-1) .M (-1) , respectively. The purified phytase exhibited broad specificity on a range of phosphorylated compounds, presenting activity on sodium phytate, p-NPP, 2- naphthylphosphate, 1- naphthylphosphate, ATP, phenyl-phosphate, glucose-6-phosphate, calcium phytate and other substrates. Enzymatic activity was slightly inhibited by Mg (2+) , Cd (2+) , K (+) and Ca (2+) , and it was drastically inhibited by F (-) . The enzyme displayed high thermostability, retaining more than 90% activity at 60 °C during 120 h and displayed a t 1/2 of 94.5 h and 6.2 h at 70 °C and 80 °C, respectively. The enzyme demonstrated strong resistance toward pepsin and trypsin, and it retained more than 90% residual activity for both enzymes after 1 h treatment. Additionally, the enzyme efficiently hydrolyzed phytate in livestock feed, liberating 15.3 μmol phosphate/mL after 2.5 h of treatment.
Full Text Available 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 ΔoafA 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 ΔoafA 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.
Sode, Koji; Loew, Noya; Ohnishi, Yosuke; Tsuruta, Hayato; Mori, Kazushige; Kojima, Katsuhiro; Tsugawa, Wakako; LaBelle, Jeffrey T; Klonoff, David C
In this study, a novel fungus FAD dependent glucose dehydrogenase, derived from Aspergillus niger (AnGDH), was characterized. This enzyme's potential for the use as the enzyme for blood glucose monitor enzyme sensor strips was evaluated, especially by investigating the effect of the presence of xylose during glucose measurements. The substrate specificity of AnGDH towards glucose was investigated, and only xylose was found as a competing substrate. The specific catalytic efficiency for xylose compared to glucose was 1.8%. The specific activity of AnGDH for xylose at 5mM concentration compared to glucose was 3.5%. No other sugars were used as substrate by this enzyme. The superior substrate specificity of AnGDH was also demonstrated in the performance of enzyme sensor strips. The impact of spiking xylose in a sample with physiological glucose concentrations on the sensor signals was investigated, and it was found that enzyme sensor strips using AnGDH were not affected at all by 5mM (75mg/dL) xylose. This is the first report of an enzyme sensor strip using a fungus derived FADGDH, which did not show any positive bias at a therapeutic level xylose concentration on the signal for a glucose sample. This clearly indicates the superiority of AnGDH over other conventionally used fungi derived FADGDHs in the application for SMBG sensor strips. The negligible activity of AnGDH towards xylose was also explained on the basis of a 3D structural model, which was compared to the 3D structures of A. flavus derived FADGDH and of two glucose oxidases.
Full Text Available ABSTRACTThis work studied the acid phosphatase (APase activity from culture medium (extracellular, eAPase and mycelial extract (intracellular, iAPase ofAspergillus niger F111. The influence of fungus growth and phosphate concentration of the media on the synthesis and secretion of phosphatase was demonstrated. The effects of pH, substrate concentration and inorganic and organic compounds added to the reaction mixture on APase activity were also studied. Both enzymes were repressed by high concentrations of phosphate. Overexpression of iAPase in relation to eAPase was detected; iAPase activity was 46.1 times higher than eAPase. The maximal activity of eAPase was after 24h of fungus growth and for iAPase was after 96h. Optimal pH and substrate concentrations were 4.5 and 8.0 mM, respectively. Michaelis-Menten constant (Km for the hydrolysis of p-nitrophenyl phosphate was 0.57 mM with Vmax = 14,285.71 U mg-1 mycelium for the iAPase and 0.31 mM with V max = 147.06 U mg-1 mycelium for eAPase. Organic substances had little effect on acid phosphatases when compared with the salts. Both the APases were inhibited by 10 mM KH 2PO4 and 5 mM (NH42MoO4; eAPase was also inhibited by 1 mM CoCl2.
Nitsche Benjamin M
Full Text Available Abstract Background Filamentous fungi are confronted with changes and limitations of their carbon source during growth in their natural habitats and during industrial applications. To survive life-threatening starvation conditions, carbon from endogenous resources becomes mobilized to fuel maintenance and self-propagation. Key to understand the underlying cellular processes is the system-wide analysis of fungal starvation responses in a temporal and spatial resolution. The knowledge deduced is important for the development of optimized industrial production processes. Results This study describes the physiological, morphological and genome-wide transcriptional changes caused by prolonged carbon starvation during submerged batch cultivation of the filamentous fungus Aspergillus niger. Bioreactor cultivation supported highly reproducible growth conditions and monitoring of physiological parameters. Changes in hyphal growth and morphology were analyzed at distinct cultivation phases using automated image analysis. The Affymetrix GeneChip platform was used to establish genome-wide transcriptional profiles for three selected time points during prolonged carbon starvation. Compared to the exponential growth transcriptome, about 50% (7,292 of all genes displayed differential gene expression during at least one of the starvation time points. Enrichment analysis of Gene Ontology, Pfam domain and KEGG pathway annotations uncovered autophagy and asexual reproduction as major global transcriptional trends. Induced transcription of genes encoding hydrolytic enzymes was accompanied by increased secretion of hydrolases including chitinases, glucanases, proteases and phospholipases as identified by mass spectrometry. Conclusions This study is the first system-wide analysis of the carbon starvation response in a filamentous fungus. Morphological, transcriptomic and secretomic analyses identified key events important for fungal survival and their chronology. The
OKKY SETYAWATI DHARMAPUTRA
Full Text Available The effects of nontoxigenic Aspergillus flavus, A. niger and Trichoderma harzianum inoculated into planting media on toxigenic A. flavus infection and its aflatoxin production in peanut kernels at harvest were investigated together with (1 the moisture content of planting media before peanut planting, at the time of inflorescence, and at harvest, (2 the population of aflatoxigenic and nonaflatoxigenic A. flavus, A. niger and T. harzianum in peanut planting media before peanut planting, at the time of inflorescence, and at harvest, (3 the moisture content of peanut kernels at harvest, and (4 toxigenic A. flavus invasion in peanut plant parts (r oots, stems, petioles, leaves and flowers at the time of inflorescence. The fungal isolates were inoculated into planting media at the same time with the planting of peanut seeds. Peanut plants were grown under glasshouse conditions. Treated planting media were inoculated with the combined use of (1 toxigenic and nontoxigenic A. flavus, (2 toxigenic A. flavus and A. niger, and (3 toxigenic A. flavus and T. harzianum. Planting media inoculated only with each fungal isolat e and uninoculated planting media were used as controls. Two watering treatments of peanut plants were carried out, i.e. watering un til harvest and not watering for 15 days before harvest. The populations of the fungal isolates in the planting media and peanut kernels were determined using dilution method followed by pour plate method; the percentages of toxigenic A. flavus and test fungal colonizations in peanut plant parts were de termined using plating method; the moisture content of planting media and peanut kernels were determined using oven method; the aflatoxin content of peanut kernels was determined using Thin Layer Chromatography method. The results indicated that at the time of harvest the decr ease in moisture contents of planting media not watered for 15 days before harvest was higher than those watered until harvest. The
Safaa Abd Alrasool Ali
In this study biomass filter of Candida Utilis which isolated from food sample in Baghdad local market and Aspergillus Niger which isolated from Baghdad soil used to biosorption heavy metals from synthesis industrial wastewater. two bio-filters were designed as cylindrical Perspex with height 10cm, diameter 3cm as a shell and inside their are layers of Sponge were prepare as the size of diameter of the cylindrical filter with thickness of 2cm arrange inside it, biomass production were 6 g of ...
筛选了1株高产木聚糖酶的黑曲霉(Aspergillus niger)An-238菌株,研究了其在固态培养基中的产酶条件.该菌株发酵曲中除含有木聚糖酶5 117 U/g(干曲)外,还有纤维素酶425 U/g(干曲),果胶酶1 236 U/g(干曲),蛋白酶22 531 U/g(干曲).
Full Text Available Glucose oxidase (GOx is the basic stone for many of biological industry worldwide. The improvement of GOx production basically depends on selection of hyper producer strain of Aspergillus niger. Selective isolation and screening for natural hyper producer strains of A. niger and sequence analysis of the GOD gene, which is responsible for production of the enzyme, are very effective approaches to investigate the naturally modified strains of A. niger with hyper productive capacity of GOx enzyme. The aims of the current study were selective isolation of naturally hyper GOx producing strains of A. niger and evaluation of their GOx activities under optimized parameters in the laboratory. Five wild Egyptian isolates of A. niger were screened for GOx and catalase activity using two types of modified basal liquid media. The GOx activity was evaluated by high throughout liquid phase system. The isolates showed a variable activity for GOx production ranged from 0 to 28.7 U.ml-1. One isolate coded Strain 7 was negative GOx producer on Vogel's broth medium in comparison to other isolates, while its GOx activity on Cazpek Dox was considered as positive (7.28 U.ml-1. It was concluded that GOx production is affected by three controllable factors – the basal media components, time of incubation, and the strain with its adaption to the media components. Also, the catalase activity was tested and it was produced with a different degree of variability, which may be reflected on GOx stability. GOD genes of these wild variant of A. niger were cloned and sequenced to determine intraspecies diversity of GOD between the wild variants. The comparison of isolated wild variants to other reference hyper GOx producer strains of A. niger was performed to determine if the GOD sequence analysis of these strains can be distinguished based on their GOx activity. This is the first report for isolation and detection of naturally A. niger hyper GOx-producer strains with
Full Text Available Today, it is very important to find out the protection of products of natural origin as an alternative to synthetic fungicides. The promising alternative is the use of the essential oils (EOs. Essential oils from plants have great potential as a new source of fungicide to control the pathogenic fungi.The main objective of this study was evaluation of the antifungal activity of lemon (Citrus lemon L., eucalyptus (Eucalyptus globulus LABILL., thyme (Thymus vulgaris L., oregano (Origanum vulgare L. sage (Salvia officinalis L. and lavender (Lavandula angustifolia MILLER. EOs against Aspergillus niger and Aspergillus tubingensis isolated from grapes and their ability to affect the growth. It was tested by using the vapor contact with them. At first both tested isolates were identified by using PCR method. Sequence data of 18S rRNA supported the assignment of these isolates to the genus Aspergillus and species A. niger (ITS region: KT824061; RPB2: KT824060 and A. tubingensis (ITS region: KT824062; RPB2: KT824059. Second, EO antifungal activity was evaluated. The effect of the EO volatile phase was confirmed to inhibit growth of A. niger and A tubingensis. EOs were diluted in DMSO (dimethyl sulfoxide final volume of 100 μL. Only 50 μL this solution was distributed on a round sterile filter paper (1 x 1 cm by micropipette, and the paper was placed in the center of the lid of Petri dishes. Dishes were kept in an inverted position. The essential oils with the most significant activity were determined by method of graded concentration of oils - minimum inhibitory doses (MIDs. The most effective tested EOs were oregano and thyme oils, which totally inhibited growth of tested isolates for all days of incubation at 0.625 μL.cm-3 (in air with MFDs 0.125 μL.cm-3 (in air. Lavender EO was less active aginst tested strains (MIDs 0.313 μL.cm-3. The results showed that the tested EOs had antifungal activity, except lemon and eucalyptus. Sage EO was the only
Passamani, Fabiana Reinis Franca; Hernandes, Thais; Lopes, Noelly Alves; Bastos, Sabrina Carvalho; Santiago, Wilder Douglas; Cardoso, Maria das Graças; Batista, Luís Roberto
The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33°C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37°C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 μg/g and 7.0 μg/g, respectively) were found at 15°C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes.
Medina, A.; Jakobsen, Iver; Vassilev, N.;
Sugar beet waste has potential value as a soil amendment and this work studied whether fermentation of the waste by Aspergillus niger would influence the growth and P uptake of arbuscular mycorrhizal (AM) fungi. Plants were grown in compartmentalised growth units, each with a root compartment (RC...... of exudates by A. niger, as a consequence of fermentation process of sugar beet waste, could possibly explain the increase of AM growth in ASB treatments. On the other hand, the highest P uptake was a result of the solubilisation of rock phosphate by A. niger during the fermentation. (c) 2006 Elsevier Ltd...
Full Text Available O trabalho teve por objetivo avaliar a viabilidade do uso da manipueira, residuo líquido resultante da prensagem da massa ralada de mandioca, como substrato na biossíntese de ácido cítrico por Aspergillus niger. Os meios de manipueira foram comparados nas mesmas condições de temperatura, a meios sintéticos, utilizados tradicionalmente. Em se tratando de proposta de um novo substrato, foi estudado o armazenamento do resíduo a temperatura ambiente por 72 horas, e realizada a caracterização físico-química da manipueira e dos meios elaborados com esse substrato. Foi avaliada a produção de ácido cítrico nos meios sintéticos e de manipueira. Verificou-se que a produção de ácido cítrico não diferiu quanto ao meio. Não foi observado crescimento do microrganismo nos meios de manipueira com concentrações acima de 70 mg/l de cianeto. Os resultados obtidos mostraram necessidade de maiores estudos para viabilizar o uso da manipueira como substrato na biossíntese de ácido cítrico por A. niger, principalmente no que diz respeito à liberação enzimática do cianeto.This research was made to evaluate the manipueira as substrat for citric acid biosynthesis by Aspergillus niger. The manipueira medium was compared in the same conditions of the synthetical medium, traditionally used in citric acid biosynthesis. The residue was kept at room temperature during 72 hours, and the physico-chemical characterization was made. The citric acid production did not change in the different media and the fungus did not grow hi the manipueira medium with concentrations about of 70 mg/l of cyanide. The results showed that more research is need to make manipueira utilization possible as a substrat for citric acid biosynthesis by Aspergillus niger.
Increased resistance to 14α-demethylase inhibitors (DMIs) in Aspergillus niger by coexpression of the Penicillium italicum eburicol 14α-demethylase (cyp51) and the A. Niger cytochrome P450 reductase (cprA) genes
Brink, H.J.M. van den; Nistelrooy, H.J.G.M. van; Waard, M.A. de; Hondel, C.A.M.J.J. van den; Gorcom, R.F.M. van
In this paper we describe the effects of over-expression of the Penicillium italicum gene encoding eburicol 14α-demethylase (cyp51), in Aspergillus niger strains with one or multiple copies of the gene encoding cytochrome P450 reductase (cpr A), on the eburicol 14α-demethylase activity. Eburicol 14α
Singh, O V; Sharma, A; Singh, R P
Aspergillus niger ORS-4.410, a mutant of Aspergillus niger ORS-4 was produced by repeated irradiation with UV rays. Treatments with chemical mutagnes also resulted into mutant strains. The mutants differed from the parent strain morphologically and in gluconic acid production. The relationship between UV treatment dosage, conidial survival and frequency of mutation showed the maximum frequency of positive mutants (25%) was obtained along with a conidial survival of 59% after second stage of UV irradiation. Comparison of gluconic acid production of the parent and mutant ORS-4.410 strain showed a significant increase in gluconic acid production that was 87% higher than the wild type strain. ORS-4.410 strain when transferred every 15 days and monitored for gluconic acid levels for a total period of ten months appeared stable. Mutant ORS-4.410 at 12% substrate concentration resulted into significantly higher i.e. 85-87 and 94-97% yields of gluconic acid under submerged and solid state surface conditions respectively. Further increase in substrate concentration appeared inhibitory. Maximum yield of gluconic acid was obtained after 6 days under submerged condition and decreased on further cultivation. Solid state surface culture condition on the other hand resulted into higher yield after 12 days of cultivation and similar levels of yields continued thereafter.
Manzanares-Miralles, Lara; Sarikaya-Bayram, Özlem; Smith, Elizabeth B; Dolan, Stephen K; Bayram, Özgür; Jones, Gary W; Doyle, Sean
Gliotoxin (GT) is a redox-active metabolite, produced by Aspergillus fumigatus, which inhibits the growth of other fungi. Here we demonstrate how Aspergillus niger responds to GT exposure. Quantitative proteomics revealed that GT dysregulated the abundance of 378 proteins including those involved in methionine metabolism and induced de novo abundance of two S-adenosylmethionine (SAM)-dependent methyltransferases. Increased abundance of enzymes S-adenosylhomocysteinase (p=0.0018) required for homocysteine generation from S-adenosylhomocysteine (SAH), and spermidine synthase (p=0.0068), involved in the recycling of Met, was observed. Analysis of Met-related metabolites revealed significant increases in the levels of Met and adenosine, in correlation with proteomic data. Methyltransferase MT-II is responsible for bisthiobis(methylthio)gliotoxin (BmGT) formation, deletion of MT-II abolished BmGT formation and led to increased GT sensitivity in A. niger. Proteomic analysis also revealed that GT exposure also significantly (pniger. Thus, it provides new opportunities to exploit the response of GT-naïve fungi to GT.
Mezeli, Malika; Menezes-Blackburn, Daniel; Zhang, Hao; Giles, Courtney; George, Timothy; Shand, Charlie; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Stutter, Marc; Blackwell, Martin; Darch, Tegan; Wearing, Catherine; Haygarth, Philip
Current developments in cropping systems that promote mobilisation of phytate in agricultural soils, by exploiting plant-root exudation of phytase and organic acids, offer potential for developments in sustainable phosphorus use. However, phytase adsorption to soil particles and phytate complexion has been shown to inhibit phytate dephosphorylation, thereby inhibiting plant P uptake, increasing the risk of this pool contributing to diffuse pollution and reducing the potential benefits of biotechnologies and management strategies aimed to utilise this abundant reserve of 'legacy' phosphorus. Citrate has been seen to increase phytase catalytic efficiency towards complexed forms of phytate, but the mechanisms by which citrate promotes phytase remains poorly understood. In this study, we evaluated phytase (from Aspergillus niger) inactivation, and change in catalytic properties upon addition to soil and the effect citrate had on adsorption of phytase and hydrolysis towards free, precipitated and adsorbed phytate. A Langmuir model was fitted to phytase adsorption isotherms showing a maximum adsorption of 0.23 nKat g-1 (19 mg protein g-1) and affinity constant of 435 nKat gˉ1 (8.5 mg protein g-1 ), demonstrating that phytase from A.niger showed a relatively low affinity for our test soil (Tayport). Phytases were partially inhibited upon adsorption and the specific activity was of 40.44 nKat mgˉ1 protein for the free enzyme and 25.35 nKat mgˉ1 protein when immobilised. The kinetics of adsorption detailed that most of the adsorption occurred within the first 20 min upon addition to soil. Citrate had no effect on the rate or total amount of phytase adsorption or loss of activity, within the studied citrate concentrations (0-4mM). Free phytases in soil solution and phytase immobilised on soil particles showed optimum activity (>80%) at pH 4.5-5.5. Immobilised phytase showed greater loss of activity at pH levels over 5.5 and lower activities at the secondary peak at pH 2
Krijgsheld, Pauline; Nitsche, Benjamin M; Post, Harm; Levin, Ana M; Müller, Wally H; Heck, Albert J R; Ram, Arthur F J; Altelaar, A F Maarten; Wösten, Han A B
Aspergillus niger is a cell factory for the production of enzymes. This fungus secretes proteins in the central part and at the periphery of the colony. The sporulating zone of the colony overlapped with the nonsecreting subperipheral zone, indicating that sporulation inhibits protein secretion. Indeed, strain ΔflbA that is affected early in the sporulation program secreted proteins throughout the colony. In contrast, the ΔbrlA strain that initiates but not completes sporulation did not show altered spatial secretion. The secretome of 5 concentric zones of xylose-grown ΔflbA colonies was assessed by quantitative proteomics. In total 138 proteins with a signal sequence for secretion were identified in the medium of ΔflbA colonies. Of these, 18 proteins had never been reported to be part of the secretome of A. niger, while 101 proteins had previously not been identified in the culture medium of xylose-grown wild type colonies. Taken together, inactivation of flbA results in spatial changes in secretion and in a more complex secretome. The latter may be explained by the fact that strain ΔflbA has a thinner cell wall compared to the wild type, enabling efficient release of proteins. These results are of interest to improve A. niger as a cell factory.
Vakilchap, F; Mousavi, S M; Shojaosadati, S A
Annual worldwide growth rate of red mud (RM) as a hazardous waste has caused serious environmental problems for its disposal in the mining and metallurgy industries. Accordingly, the aim of this study was to investigate biological leaching of RM and recovery of metals using organic acids exerted by Aspergillus niger. Experiments using A. niger were conducted in batch cultures with a pulp density of 2% (w/v) RM under one-step, two-step and spent-medium bioleaching. Based on HPLC results, the major lixiviant was the secretion of organic acids (citric, gluconic, oxalic and malic) by A. niger. Leaching efficiency of metals in the one-step process was the highest and the amounts of leached metals were 69.8%, 60% and 25.4% for Al, Ti and Fe, respectively. The fungal leaching technique demonstrated an adequate recovery of metals, with an efficient and cost-effective means and respect to a reuse of RM for economic and environmental purposes.
Veana, Fabiola; Fuentes-Garibay, José Antonio; Aguilar, Cristóbal Noé; Rodríguez-Herrera, Raúl; Guerrero-Olazarán, Martha; Viader-Salvadó, José María
β-Fructofuranosidases or invertases (EC 22.214.171.124) 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 1770 bp 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 4.2 L culture with the constructed recombinant P. pastoris strain showed an extracellular and periplasmic invertase production at 72 h induction of 498 and 3776 invertase units (U), respectively, which corresponds to 1018 U/L of culture medium. The invertase produced had an optimum pH of 5.0, optimum temperature of 60 °C, and specific activity of 3389 U/mg protein, and after storage for 96 h at 4 °C showed 93.7% of its activity. This invertase could be suitable for producing inverted sugar used in the food industry.
Corbellini Luís G.
Full Text Available As infecções micóticas apresentam distribuição mundial e podem causar placentite e aborto em diversas espécies de animais. Entre setembro 2001 e novembro 2002, foram processados no Setor de Patologia Veterinária, Universidade Federal do Rio Grande do Sul, 147 fetos bovinos abortados com o objetivo de avaliar as principais causas de aborto infeccioso bovino no sul do Brasil. Destes, 34 estavam acompanhados da placenta. Aborto micótico foi diagnosticado em cinco casos (3,4% mediante cultivo puro de quatro amostras de Aspergillus fumigatus e uma de A. niger associado a lesões histológicas características de fungo. Os exames virológico, bacteriológico e imunofluorescência direta para Leptospira sp foram negativos nestes casos. A idade dos fetos variava entre 5 e 8 meses de idade. Lesões macroscópicas foram observadas em quatro casos e eram caracterizadas por áreas circulares multifocais branco-acinzentadas na pele, principalmente na região da cabeça e dorso, em dois fetos, lesões nodulares no fígado em um caso e espessamento dos cotilédones em duas placentas enviadas juntamente com os fetos. Lesões histológicas foram observadas principalmente no fígado, pulmão e placenta, caracterizadas por hepatite necrótica multifocal, broncopneumonia supurativa e placentite necrótica. Através da coloração de Grocott hifas septadas foram observadas em duas placentas e nas bordas das lesões necróticas no fígado de um feto. Em dois casos hifas foram observadas somente na placenta e não no feto, salientando-se a importância deste tecido para o diagnóstico de aborto micótico bovino.
Kumpoun, Wilawan; MOTOMURA, Yoshie
リンゴやモモの貯蔵病害の一つとして，Aspergillus 菌によるコウジカビ病が知られている。本報では，24種類の果実の果肉から熱水で抽出したペクチン性多糖類に，Aspergillus niger 由来のペクチナーゼを作用させ，その前後の多糖類の分子量分布をゲル濾過によって分析した。得られた溶出パターンの中でピークの変化の程度によって，ペクチン分子のペクチナーゼによる分解の難易を比較した。リンゴ，ウメ，マンゴーではピークの低分子側への変化が大きかったが，アボカド，ドリアン，ブドウ，キーウィー，ビワ，メロン，ライチー，パパイヤ及びランブータンでは変化が小さかった。マンゴーとパパイヤの未熟果と成熟果のペクチン性多糖類のこの酵素による分解性を見たところ，成熟段階に関わらず，マンゴーでは分子量の減少が大きかったが，パパイヤではほとんど変化が見られなかった。ペクチン性多糖類の同一酵素による分解性に差異が生じる原因について，細胞壁多糖の組成や構造の種特異性などの可能性を考察した。...
Battaglia, Evy; Zhou, M.; de Vries, Ronald P; van den Brink, J.
The pentose catabolic pathway (PCP) and the pentose phosphate pathway (PPP) are required for the conversion of pentose sugars in fungi and are linked via d-xylulose-5-phosphate. Previously, it was shown that the PCP is regulated by the transcriptional activators XlnR and AraR in Aspergillus niger. H
Yuan, X.-L.; Kaaij, R.M. van der; Hondel, C.A.M.J.J. van den; Punt, P.J.; Maarel, M.J.E.C. van der; Dijkhuizen, L.; Ram, A.F.J.
The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material. A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of α-amylase, glucoamy
Alternative tactics for improving phosphorus nutrition in crop production are needed in China and elsewhere as the over-application of phosphatic fertilizers can adversely impact agricultural sustainability. Penicillium oxalicum P4 and Aspergillus niger P85 were isolated from a calcareous soil in C...
Fumonisins are mycotoxins associated with cancer and several other serious diseases in humans and animals. Production of the mycotoxins has been reported for over two decades in Fusarium species, but has been reported only recently in strains of Aspergillus niger. In addition, a homologue of the f...
Phytases are of biotechnological importance as animal feed additives for their ability to catalyze the hydrolysis of phosphate from phytate for absorption by simple-stomached animals, and to reduce their fecal phosphorus excretion. Aspergillus niger PhyB has high catalytic activity at low pHs around...
This study was to compare three phytase activity assays and kinetics of Aspergillus niger PhyA and Escherichia coli AppA2 phytases expressed in Pichia pastoris at the observed stomach pH of 3.5. In Experiment 1, equivalent phytase activities in the crude preparations of PhyA and AppA2 were tested ...
The fungi Aspergillus niger and A. welwitschiae are morphologically indistinguishable species used for industrial fermentation and for food and beverage production. The fungi also occur widely on food crops. Concerns about their safety have arisen with the discovery that some isolates of both specie...
Yang, Peizhou; Zhang, Haifeng; Cao, Lili; Zheng, Zhi; Jiang, Shaotong
Aspergillus niger is an important microorganism that has been used for decades to produce extracellular enzymes. In this study, a novel Aspergillus niger strain integrated with a eukaryotic expression vector harboring the gpd-Shi promoter of shiitake mushrooms and cellulase gene of Ampullaria gigas Spix was engineered to improve cellulase production for the achievement of highly efficient saccharification of agricultural residues. In one strain, designated ACShi27, which exhibited the highest total cellulase expression, total cellulase, endoglucanase, exoglucanase, and xylanase expression levels were 1.73, 16.23, 17.73, and 150.83 U ml(-1), respectively; these values were 14.5, 22.3, 24.6, and 17.3% higher than those of the wild-type Aspergillus niger M85 using wheat bran as an induction substrate. Production of cellulases and xylanase by solid-state fermentation followed by in situ saccharification of ACShi27 was investigated with alkaline-pretreated rice straw as a substrate. After 2 days of enzyme induction at 30 °C, followed by 48 h of saccharification at 50 °C, the conversion rate of carbon polymers into reducing sugar reached 293.2 mg g(-1), which was 1.23-fold higher than that of the wild-type strain. The expression of sestc in Aspergillus niger can improve the total cellulase and xylanase activity and synergism, thereby enhancing the lignocellulose in situ saccharification.
Bourne, Y.; Hasper, A.A.; Chahinian, H.; Juin, M.; Graaff, de L.H.
From the fungus Aspergillus niger, we identified a new gene encoding protein EstA, a member of the alpha/beta-hydrolase fold superfamily but of unknown substrate specificity. EstA was overexpressed and its crystal structure was solved by molecular replacement using a lipaseacetylcholinesterase chime
Full Text Available The result of laboratory analysis on bioethanol waste shows nutritional and anti-nutritional content (HCN. Based on it, in order to prevent environment damage then performed a bioconversion of bioethanol waste for base material of sheep forage by fermented previously using consortium of Saccharomyces cerevisiae, Trichoderma viride, and Aspergillus niger to eliminate the waste anti-nutritional content and increase nutritional content. This research used Completely Randomized Design (CRD factorial pattern with two factors and three replications. The first factor was inoculum dose (D and the second factor was variation of tested microorganisms (M. The variables measured were HCN content and nutrient content of fermented products, that were water content, protein content and crude fiber content by proximate analysis. Furthermore, the data was statistically analyzed by analysis of variance (ANOVA, and was there significant difference analyzed further by Duncan's multiple range test of 5% level. Nutritional compositions of bioethanol waste from cassava that had been fermented by consortium of Saccharomyces cerevisiae, Trichoderma viride, and Aspergillus niger experienced changes compared to before fermentation. The results showed an increase in protein level, while fiber content, water content, and HCN content were decrease. Bioethanol waste from cassava fermented by Aspergillus niger and Saccharomyces cerevisiae (k3 with 2% inoculum dose had the highest protein content increase from 11.79% to 25.41% and had the lowest crude fiber content decrease from 16.4% to 12.84 %. The highest HCN decrease obtained from the fermentation of consortium Aspergillus niger and Trichoderma viride.
Oberoi, Harinder Singh; Rawat, Rekha; Chadha, Bhupinder Singh
Fungi isolated from partially decayed wood log samples showing characteristic diversity for spore colour, colony morphology and arrangement of spores were assessed for cellulolytic enzyme production. Isolates showing a cellulolytic index of ≥2.0 were assayed for filter paper (FP) cellulase and β-glucosidase (BGL) production. Molecular characterization confirmed the identity of the selected cellulolytic isolate as a strain of Aspergillus niger (A. niger HN-2). Addition of 2 % (w/v) urea enhanced FP and BGL activity by about 20 and 60 %, respectively. Validation studies conducted at parameters (29 °C, pH 5.4, moisture content 72 % and 66 h) optimized through response surface methodology in a solid-state static tray fermentation resulted in FP, BGL, cellobiohydrolase I (CBHI), endoglucanase (EG), xylanase activity and protein content of 25.3 FPU/g ds, 750 IU/g ds, 13.2 IU/g ds, 190 IU/g ds, 2890 IU/g ds and 0.9 mg/ml, respectively. In comparison, A. niger N402 which is a model organism for growth and development studies, produced significantly lower FP, BGL, CBHI, EG, xylanase activity and protein content of 10.0 FPU/g ds, 100 IU/g ds, 2.3 IU/g ds, 50 IU/g ds, 500 IU/g ds and 0.75 mg/ml, respectively under the same process conditions as were used for A. niger HN-2. Process optimization led to nearly 1.8- and 2.2-fold increase in FP and BGL activity, respectively showing promise for cellulase production by A. niger HN-2 at a higher scale of operation. Zymogram analysis revealed two isoforms each for EG and cellobiohydrolase and three isoforms for BGL. Crude cellulase complex produced by A. niger HN-2 exhibited thermostability under acidic conditions showing potential for use in biofuel industry.
Chiang, Yi Ming; Meyer, Kristen M; Praseuth, Michael; Baker, Scott E; Bruno, Kenneth S; Wang, Clay C
The genome sequencing of the fungus Aspergillus niger, an industrial workhorse, uncovered a large cache of genes encoding enzymes thought to be involved in the production of secondary metabolites yet to be identified. Identification and structural characterization of many of these predicted secondary metabolites are hampered by their low concentration relative to the known A. niger metabolites such as the naphtho-γ-pyrone family of polyketides. We deleted a nonreducing PKS gene in A. niger strain ATCC 11414, a daughter strain of A. niger ATCC strain 1015 whose genome was sequenced by the DOE Joint Genome Institute. This PKS encoding gene is a predicted ortholog of alb1 from Aspergillus fumigatus which is responsible for production of YWA1, a precursor of fungal DHN melanin. Our results show that the A. niger alb1 PKS is responsible for the production of the polyketide precursor for DHN melanin biosynthesis. Deletion of alb1 elimnates the production of major metabolites, naphtho-γ-pyrones. The generation of an A. niger strain devoid of naphtho-γ-pyrones will greatly facilitate the elucidation of cryptic biosynthetic pathways in this organism.
李淑娟; 郭润芳; 于宏伟; 贾英民
利用PCR及RT-PCR技术从黑曲霉(Aspergillus niger)菌株DL116中克隆到了乳糖酶基因组DNA,cDNA序列(GENBANK ACCESSION No.EF103141).序列分析表明,乳糖酶基因组DNA序列长3368bp,其中含有8个内含子,cDNA编码区长2967bp,共编码988个氨基酸,氨基酸序列中共含有12个潜在的糖基化位点.并将此基因与不同来源的乳糖酶基因进行了同源性比较.
Almeida, E J R; Corso, C R
Azo dyes are an important class of environmental contaminants and are characterized by the presence of one or more azo bonds (-N=N-) in their molecular structure. Effluents containing these compounds resist many types of treatments due to their molecular complexity. Therefore, alternative treatments, such as biosorption and biodegradation, have been widely studied to solve the problems caused by these substances, such as their harmful effects on the environment and organisms. The aim of the present study was to evaluate biosorption and biodegradation of the azo dye Procion Red MX-5B in solutions with the filamentous fungi Aspergillus niger and Aspergillus terreus. Decolorization tests were performed, followed by acute toxicity tests using Lactuca sativa seeds and Artemia salina larvae. Thirty percent dye removal of the solutions was achieved after 3 h of biosorption. UV-Vis spectroscopy revealed that removal of the dye molecules occurred without major molecular changes. The acute toxicity tests confirmed lack of molecular degradation following biosorption with A. niger, as toxicity to L. sativa seed reduced from 5% to 0%. For A. salina larvae, the solutions were nontoxic before and after treatment. In the biodegradation study with the fungus A. terreus, UV-Vis and FTIR spectroscopy revealed molecular degradation and the formation of secondary metabolites, such as primary and secondary amines. The biodegradation of the dye molecules was evaluated after 24, 240 and 336 h of treatment. The fungal biomass demonstrated considerable affinity for Procion Red MX-5B, achieving approximately 100% decolorization of the solutions by the end of treatment. However, the solutions resulting from this treatment exhibited a significant increase in toxicity, inhibiting the growth of L. sativa seeds by 43% and leading to a 100% mortality rate among the A. salina larvae. Based on the present findings, biodegradation was effective in the decolorization of the samples, but generated
通过富集培养,从空气中分离到一株脱色真菌,经初步鉴定为黑曲霉(Aspergillus niger),定名为ZH-1并研究了该菌株ZH-1对活性红ST-2BF脱色的条件,结果表明,其对活性红ST-2BF的最佳脱色条件为:pH=6.0、温度30℃、在此条件下运行40 h脱色率达99.1%;探讨了碳源、氮源和接种量对其脱色率的影响;并对染料降解前后的紫外-可见光光谱进行了分析对比.图5 参6
利用黑曲霉Aspergillus niger S菌株,通过液体发酵的方法,得到了一种可同时高效水解大豆异黄酮糖苷成大豆异黄酮,水解白藜芦醇苷成白藜芦醇的糖基水解酶.该酶经硫酸铵分级沉淀、离子交换层析及分子排阻色谱纯化得单一条带,经SDS聚丙烯酰胺凝胶电泳测得该酶的表观分子量约为165ku①,比通常所报道的传统β-葡糖苷酶都大,该酶的最适反应温度为50℃;最适pH值为5～10.
李志坚; 谭兴和; 李高阳
The fermentation conditions for Aspergillus niger C15 naringinase production were optimalized by orthogonal experiment.The experimental result indicated that the best fermentation conditions was as follows:2% citrus peel meal and 6% soybean meal,30mL culture media in 250mL beaker flask,3% inoculation amount,initial pH 5,incubation temperature 30℃,time 100h.Under these optimized conditions,the yielding capacity of naringinase by the mutant was 1395.9U/mL,which was increased by 8.6% compared with the initial level(1285.6U/mL).Proper quantity of K2HPO4 and MgSO4 could improve naringinase production,CuSO4,FeSO4 were bad for producing enzyme.%通过正交实验对黑曲霉菌株C15产柚苷酶的发酵条件进行了优化。实验结果表明,Aspergillus niger C15菌株的最优产酶发酵条件为：2%桔皮粉、6%豆粕粉,250mL三角瓶中装料30mL,接种量3%,最适初始pH为5.0,30℃条件下培养100h,产酶量可达1395.9U/mL。与原始产酶条件相比,产酶量提高8.6%。不同的金属离子对产酶有不同的作用,添加适量的K2HPO4、MgSO4对产酶有明显的促进作用,CuSO4、FeSO4对产酶起抑制作用。
[Effect of alcoholic extracts of wild plants on the inhibition of growth of Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium moniliforme and Fusarium poae moulds].
Tequida-Meneses, Martín; Cortez-Rocha, Mario; Rosas-Burgos, Ema Carina; López-Sandoval, Susana; Corrales-Maldonado, Consuelo
Fungicidal activity of wild plants Larrea tridentata, Karwinskia humboldtiana, Ricinus communis, Eucalyptus globulus, Ambrosia ambrosioides, Nicotiana glauca, Ambrosia confertiflora, Datura discolor, Baccharis glutinosa, Proboscidea parviflora, Solanum rostratum, Jatropha cinerea, Salpianthus macrodonthus y Sarcostemma cynanchoides was evaluated against the moulds species Aspergillus flavus, Aspergillus niger, Penicillium chrysogenum, Penicillium expansum, Fusarium poae y Fusarium moniliforme moulds species. Alcoholic extracts 6% (w/v) were prepared using six grams of dried plant powders (leaves and stems) and alcohol (70% ethanol or 70% methanol). A spore suspension (1x10(6); ufc/ml) of each mould was prepared by adding saline solution (0.85%) and 0.1% tween 80. The extracts were mixed with Czapeck yeast agar (CYA) at 45-50 degrees C in 1:10 relation on Petri dishes. Triplicate Petri dishes of each treatment and for each mould were centrally inoculated and three Petri dishes were used without treatment as controls. The inoculated dishes and controls were incubated at 25 +/- 2 degrees C for eight days. The incubated dishes were examined each 48 h and after the colony diameter (radial growth) was measured. Two mould species were controlled by L. tridentata, B. glutinosa and P. parviflora. Extracts of L. tridentata in methanol or ethanol at 41.5-100% inhibited all six species of moulds.
Rehman, Shazia; Aslam, Hina; Ahmad, Aqeel; Khan, Shakeel Ahmed; Sohail, Muhammad
Filamentous fungi are considered to be the most important group of microorganisms for the production of plant cell wall degrading enzymes (CWDE), in solid state fermentations. In this study, two fungal strains Aspergillus niger MS23 and Aspergillus terreus MS105 were screened for plant CWDE such as amylase, pectinase, xylanase and cellulases (β-glucosidase, endoglucanase and filterpaperase) using a novel substrate, Banana Peels (BP) for SSF process. This is the first study, to the best of our knowledge, to use BP as SSF substrate for plant CWDE production by co-culture of fungal strains. The titers of pectinase were significantly improved in co-culture compared to mono-culture. Furthermore, the enzyme preparations obtained from monoculture and co-culture were used to study the hydrolysis of BP along with some crude and purified substrates. It was observed that the enzymatic hydrolysis of different crude and purified substrates accomplished after 26 h of incubation, where pectin was maximally hydrolyzed by the enzyme preparations of mono and co-culture. Along with purified substrates, crude materials were also proved to be efficiently degraded by the cocktail of the CWDE. These results demonstrated that banana peels may be a potential substrate in solid-state fermentation for the production of plant cell wall degrading enzymes to be used for improving various biotechnological and industrial processes.
Full Text Available Filamentous fungi are considered to be the most important group of microorganisms for the production of plant cell wall degrading enzymes (CWDE, in solid state fermentations. In this study, two fungal strains Aspergillus niger MS23 and Aspergillus terreus MS105 were screened for plant CWDE such as amylase, pectinase, xylanase and cellulases (β-glucosidase, endoglucanase and filterpaperase using a novel substrate, Banana Peels (BP for SSF process. This is the first study, to the best of our knowledge, to use BP as SSF substrate for plant CWDE production by co-culture of fungal strains. The titers of pectinase were significantly improved in co-culture compared to mono-culture. Furthermore, the enzyme preparations obtained from monoculture and co-culture were used to study the hydrolysis of BP along with some crude and purified substrates. It was observed that the enzymatic hydrolysis of different crude and purified substrates accomplished after 26 h of incubation, where pectin was maximally hydrolyzed by the enzyme preparations of mono and co-culture. Along with purified substrates, crude materials were also proved to be efficiently degraded by the cocktail of the CWDE. These results demonstrated that banana peels may be a potential substrate in solid-state fermentation for the production of plant cell wall degrading enzymes to be used for improving various biotechnological and industrial processes.
Salihu, Aliyu; Bala, Muntari; Bala, Shuaibu M.
Plackett-Burman design was used to efficiently select important medium components affecting the lipase production by Aspergillus niger using shea butter cake as the main substrate. Out of the eleven medium components screened, six comprising of sucrose, (NH4)2SO4, Na2HPO4, MgSO4, Tween-80, and olive oil were found to contribute positively to the overall lipase production with a maximum production of 3.35 U/g. Influence of tween-80 on lipase production was investigated, and 1.0% (v/w) of tween-80 resulted in maximum lipase production of 6.10 U/g. Thus, the statistical approach employed in this study allows for rapid identification of important medium parameters affecting the lipase production, and further statistical optimization of medium and process parameters can be explored using response surface methodology. PMID:25937979
Yusleydi Enamorado Horrutiner
Full Text Available The inactive biomass of fungus Aspergillus niger O-5 obtained in Cuba was characterized as sorbent of Pb2+ by several structural analysis and others techniques. In addition, the biomass was studied for the separation / preconcentration of Pb2+ from aqueous solution. The maximum biosorption capacity was obtained for the contact time of 30 min and pH 5. The kinetic of sorption process occurred according to the model of Ho. The Freundlich or Langmuir models suitably described the experimental adsorption isotherms. The biomass can be used as sorbent for Pb2+ with a maximum capacity of 4.7 - 6.2 mg g-1. The pretreatment with NaOH solution improved its sorption capacity.
Nasir, Nurfarahana Mohd; Bakar, Nur Syuhada Abu; Lananan, Fathurrahman; Abdul Hamid, Siti Hajar; Lam, Su Shiung; Jusoh, Ahmad
This study focuses on the evaluation of the performance of Chlorella sp. in removing nutrient in aquaculture wastewater and its correlation with the kinetic growth of Chlorella sp. The treatment was applied with various Chlorella sp. inoculation dosage ranging from 0% to 60% (v/v) of wastewater. The optimum inoculation dosage was recorded at 30% (v/v) with effluent concentration of ammonia and orthophosphate recording at 0.012mgL(-1) and 0.647mgL(-1), respectively on Day 11. The optimum dosage for bio-flocculation process was obtained at 30mgL(-1) of Aspergillus niger with a harvesting efficiency of 97%. This type of development of phytoremediation with continuous bio-harvesting could promote the use of sustainable green technology for effective wastewater treatment.
Zhang, Hongsen; Zhang, Jian; Bao, Jie
This study reported a high titer gluconic acid fermentation using dry dilute acid pretreated corn stover (DDAP) hydrolysate without detoxification. The selected fermenting strain Aspergillus niger SIIM M276 was capable of inhibitor degradation thus no detoxification on pretreated corn stover was required. Parameters of gluconic acid fermentation in corn stover hydrolysate were optimized in flasks and in fermentors to achieve 76.67 g/L gluconic acid with overall yield of 94.91%. The sodium gluconate obtained from corn stover was used as additive for extending setting time of cement mortar and similar function was obtained with starch based sodium gluconate. This study provided the first high titer gluconic acid production from lignocellulosic feedstock with potential of industrial applications.
Liu, Yu-Huan; Chung, Ying-Cheng; Xiong, Ya
A dimethoate-degrading enzyme from Aspergillus niger ZHY256 was purified to homogeneity with a specific activity of 227.6 U/mg of protein. The molecular mass of the purified enzyme was estimated to be 66 kDa by gel filtration and 67 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was found to be 5.4, and the enzyme activity was optimal at 50°C and pH 7.0. The activity was inhibited by most of the metal ions and reagents, while it was induced by Cu2+. The Michaelis constant (Km) and Vmax for dimethoate were 1.25 mM and 292 μmol min−1 mg of protein−1, respectively. PMID:11472959
Ushasree, Mrudula Vasudevan; Vidya, Jalaja; Pandey, Ashok
A phytase gene from Aspergillus niger was isolated and two Escherichia coli expression systems, based on T7 RNA polymerase promoter and tac promoter, were used for its recombinant expression. Co-expression of molecular chaperone, GroES/EL, aided functional cytosolic expression of the phytase in E. coli BL21 (DE3). Untagged and maltose-binding protein-tagged recombinant phytase showed an activity band of ~49 and 92 kDa, respectively, on a zymogram. Heterologously-expressed phytase was fractionated from endogenous E. coli phytase by (NH4)2SO4 precipitation. The enzyme had optimum activity at 50 °C and pH 6.5.
Full Text Available The screening and isolation of fungi producing a cocktail of hydrolytic enzymes was studied. Among the various isolates obtained from different soil samples, a strain NS-2 was selected. The phylogenetic analysis of this strain showed highest homology (99% with Aspergillus niger. It was capable of producing cellulolytic, hemicellulolytic, amylolytic, and pectinolytic enzymes in appreciable titers on wheat bran based liquid and solid state media. The mixture of enzymes produced by this organism could effectively hydrolyze various domestic waste residues, revealing conversion efficiencies of 89 to 92% and produced high reducing sugar yields of 0.48 to 0.66 g/g of dry residue. This enzyme cocktail could potentially find a significant application in the conversion of agricultural and other waste residues having cellulose, hemicellulose, starch, and pectin as carbohydrates to produce simpler sugars which can be fermented for the production of second generation biofuels.
Samar Kumar Pal; Tapan Kumar Das
Two cadmium resistant mutants (Cd1 and Cd2) of Aspergillus niger, among the six isolated by mutagenization with N-methyl N′-nitro-N-nitrosoguanidine (MNNG) at pH 6.4 were selected for the study. Analysis of lipid composition of the mutants and the wildtype indicated that total lipid as well as individual lipids of the cadmium resistant mutants were changed as compared with that of the wildtype. The increased activities of metal-lothionein and reduced activities of D-xylose isomerase and L-phenylalanine ammonia lyase in cell free extract of the cadmium resistant mutants suggested that mutants could allow high concentration of cadmium salt as compared with that of the wildtype. The respiratory activity and intracellular as well as extracellular Cd2+ concentration of the mutants reflected the high tolerance of the Cd mutants to cadmium ion.
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
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.
Full Text Available From mutant micelial strain Aspergillus niger 33-19 CNMN FD 02A, through alcohol ethylic precipitation of cultural liquid, amylolytic preparation Amilonigrin AS was isolated with 10x degree of purity and a specific activity of 138.3U/mg proteins. α-Amylase from 20mM Tris-HCl extract of Amilonigrin AS was purified to homogeneity by PD-10 column gel filtration and HiTrap TM Q column ion exchange chromatography. A trial for the purification of α-amylase resulted in an enzyme specific activity of 199.68U/mg protein with purification fold 8.9. The analyses of purified α-amylase for molecular weight was carried out by SDSPAGE electrophoresis, with revealed two polypeptide bands estimated to be 66 and 40.5kDa, probably being two α-amylaseizoforms.
[Influence of the interaction of temperature and water activity on the production of ochratoxin A and the growth of Aspergillus niger, Aspergillus carbonarius and Aspergillus ochraceus on coffee-based culture medium].
Kouadio, Ahou Irène; Lebrihi, Ahmed; Agbo, Georges N' Zi; Mathieu, Florence; Pfohl-Leszkowiz, Annie; Dosso, Mireille Bretin
In the present study, the effect of temperature and water activity on fungal growth and ochratoxin production on coffee-based medium was assessed. Optimal growth of three Aspergillus strains was observed in the same ecological conditions, namely 30 degrees C and 0.99 water activity. Maximal daily growth is 11.2, 6.92, and 7.22 mm/day for Aspergillus niger, Aspergillus carbonarius, and Aspergillus ochraceus, respectively. However, ecological conditions for optimal ochratoxin production vary according to the toxinogenic strain, with water activity as a limiting factor. Such an ochratoxin A production is inhibited at 42 degrees C and 0.75 water activity. Correspondence between laboratory tested water activity and that measured on a sun-dried ripe cherry batch shows that the first 5 days of drying are critical for fungal growth and ochratoxin A production. Accordingly, artificial drying of cherries at temperatures above 42 degrees C will impede not only fungal growth but also contamination with ochratoxin A.
de Billerbeck, V G; Roques, C G; Bessière, J M; Fonvieille, J L; Dargent, R
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.
Full Text Available Glucose oxidase is one of the most conspicuous commercial enzymes due to its many different applications in diverse industries such as food, chemical, energy and textile. Among these applications, the most remarkable is the manufacture of glucose biosensors and in particular sensor strips used to measure glucose levels in serum. The generation of ameliorated versions of glucose oxidase is therefore a significant biotechnological objective. We have used a strategy that combined random and rational approaches to isolate uncharacterized mutations of Aspergillus niger glucose oxidase with improved properties. As a result, we have identified two changes that increase significantly the enzyme's thermal stability. One (T554M generates a sulfur-pi interaction and the other (Q90R/Y509E introduces a new salt bridge near the interphase of the dimeric protein structure. An additional double substitution (Q124R/L569E has no significant effect on stability but causes a twofold increase of the enzyme's specific activity. Our results disclose structural motifs of the protein which are critical for its stability. The combination of mutations in the Q90R/Y509E/T554M triple mutant yielded a version of A. niger glucose oxidase with higher stability than those previously described.
Edwinoliver, N G; Thirunavukarasu, K; Purushothaman, S; Rose, C; Gowthaman, M K; Kamini, N R
Corn steep liquor (CSL) has been used as a nutrition adjunct for the production of an extracellular lipase from Aspergillus niger, which has immense importance as an additive in laundry detergent formulations. A five-level four-factorial central composite design was chosen to determine the optimal medium components with four critical variables, namely, CSL, NH4H2PO4, Na2HPO4, and sesame oil, that were found to be influential for lipase production by the classical one-factor-at-a-time method. The model suggested that all of the factors chosen had a significant impact on lipase production, and the optimum values of the influential parameters were CSL, 2.0%, w/v; NH4H2PO4, 0.05%, w/v; Na2HPO4, 0.75%, w/v; and sesame oil, 2.0%, w/v, with an activity of 26.7 U/mL at 48 h and 30 degrees C, which was 2.16-fold higher than the initial activity (12 U/mL) obtained by the conventional one-factor-at-a-time method. Furthermore, the enzyme has good potential for the hydrolysis of vegetable oils and fish oils, and a hydrolytic ratio of 88.73% was obtained with palm oil at 48 h. The utilization of CSL and sesame oil for lipase production from A. niger makes the process green, because both are renewable substrates and economically viable at an industrial scale.
Dutra, Julio C. V.; da Terzi, Selma C.; Bevilaqua, Juliana Vaz; Damaso, Mônica C. T.; Couri, Sônia; Langone, Marta A. P.; Senna, Lilian F.
The aim of this study was to monitor the biomass growth of Aspergillus niger in solid-state fermentation (SSF) for lipase production using digital image processing technique. The strain A. niger 11T53A14 was cultivated in SSF using wheat bran as support, which was enriched with 0.91% (m/v) of ammonium sulfate. The addition of several vegetable oils (castor, soybean, olive, corn, and palm oils) was investigated to enhance lipase production. The maximum lipase activity was obtained using 2% (m/m) castor oil. In these conditions, the growth was evaluated each 24 h for 5 days by the glycosamine content analysis and digital image processing. Lipase activity was also determined. The results indicated that the digital image process technique can be used to monitor biomass growth in a SSF process and to correlate biomass growth and enzyme activity. In addition, the immobilized esterification lipase activity was determined for the butyl oleate synthesis, with and without 50% v/v hexane, resulting in 650 and 120 U/g, respectively. The enzyme was also used for transesterification of soybean oil and ethanol with maximum yield of 2.4%, after 30 min of reaction.
La Ode Muhsafaat
Full Text Available This experiment was designed to evaluate protein quality and amino acid composition of fermented sago pulp by Aspergillus niger with urea and zeolit addition at different levels. The experiment was design in factorial completely randomized with two factors and three replicates. The first factor was levels of urea addition (0, 2.5, and 5%, the second factor was levels of zeolite addition (0, 2.5, and 5% and used 2% A. niger on sago pulp (dry matter form. Variables observed were the levels of crude protein and amino acids. Data were tested using descriptive and Analysis of Variance (ANOVA, the differences among treatments means examined by Duncan Multiple Range Test. The results howed that there was interaction between levels of addition urea and zeolite on crude protein value. The addition urea and zeolite at 5% had the high increased 15.49 ± 0.33% to crude protein content. The amino acid content of fermented sago pulp descriptively increased in urea treatment, but didn’t show increased in zeolite treatment. Based on the calculation of the score of chemical and index essential amino acids, fermented sago pulp at 5% urea treatment has a chemical score of 17.86, 18.01, and 11.85 with the essential amino acid deficient is leucine, and has an index of 38.33, 36.43, and 28.45%.
Sumathy, Vello; Zakaria, Zuraini; Jothy, Subramanion L; Gothai, Sivapragasam; Vijayarathna, Soundararajan; Yoga Latha, Lachimanan; Chen, Yeng; Sasidharan, Sreenivasan
Invasive aspergillosis (IA) in immunocompromised host is a major infectious disease leading to reduce the survival rate of world population. Aspergillus niger is a causative agent causing IA. Cassia surattensis plant is commonly used in rural areas to treat various types of disease. C. surattensis flower extract was evaluated against the systemic aspergillosis model in this study. Qualitative measurement of fungal burden suggested a reduction pattern in the colony forming unit (CFU) of lung, liver, spleen and kidney for the extract treated group. Galactomannan assay assessment showed a decrease of fungal load in the treatment and positive control group with galactomannan index (GMI) value of 1.27 and 0.25 on day 28 but the negative control group showed high level of galactomannan in the serum with GMI value of 3.58. Histopathology examinations of the tissues featured major architecture modifications in the tissues of negative control group. Tissue reparation and recovery from infection were detected in extract treated and positive control group. Time killing fungicidal study of A. niger revealed dependence of the concentration of C. surattensis flower extract.
Woon, J. S. K.; Murad, A. M. A.; Abu Bakar, F. D.
A cellobiohydrolase B (CbhB) from Aspergillus niger ATCC 10574 was cloned and expressed in E. coli. CbhB has an open reading frame of 1611 bp encoding a putative polypeptide of 536 amino acids. Analysis of the encoded polypeptide predicted a molecular mass of 56.2 kDa, a cellulose binding module (CBM) and a catalytic module. In order to obtain the mRNA of cbhB, total RNA was extracted from A. niger cells induced by 1% Avicel. First strand cDNA was synthesized from total RNA via reverse transcription. The full length cDNA of cbhB was amplified by PCR and cloned into the cloning vector, pGEM-T Easy. A comparison between genomic DNA and cDNA sequences of cbhB revealed that the gene is intronless. Upon the removal of the signal peptide, the cDNA of cbhB was cloned into the expression vector pET-32b. However, the recombinant CbhB was expressed in Escherichia coli Origami DE3 as an insoluble protein. A homology model of CbhB predicted the presence of nine disulfide bonds in the protein structure which may have contributed to the improper folding of the protein and thus, resulting in inclusion bodies in E. coli.
Priegnitz, Bert-Ewald; Brandt, Ulrike; Pahirulzaman, Khomaizon A K; Dickschat, Jeroen S; Fleißner, André
Adaptation to a changing environment is essential for the survival and propagation of sessile organisms, such as plants or fungi. Filamentous fungi commonly respond to a worsening of their growth conditions by differentiation of asexually or sexually produced spores. The formation of these specialized cell types is, however, also triggered as part of the general life cycle by hyphal age or density. Spores typically serve for dispersal and, therefore, translocation but can also act as resting states to endure times of scarcity. Eukaryotic differentiation in response to environmental and self-derived signals is commonly mediated by three-tiered mitogen-activated protein (MAP) kinase signaling cascades. Here, we report that the MAP kinase Fus3 of the black mold Aspergillus niger (AngFus3) and its upstream kinase AngSte7 control vegetative spore formation and secondary metabolism. Mutants lacking these kinases are defective in conidium induction in response to hyphal density but are fully competent in starvation-induced sporulation, indicating that conidiation in A. niger is triggered by various independent signals. In addition, the mutants exhibit an altered profile of volatile metabolites and secrete dark pigments into the growth medium, suggesting a dysregulation of the secondary metabolism. By assigning the AngFus3 MAP kinase pathway to the transduction of a potentially self-derived trigger, this work contributes to the unraveling of the intricate signaling networks controlling fungal differentiation. Moreover, our data further support earlier observations that differentiation and secondary metabolism are tightly linked in filamentous fungi.
Cui, Shixiu; Wang, Tianwen; Hu, Hong; Liu, Liangwei; Song, Andong; Chen, Hongge
There exist significant differences between the 2 main types of xylanases, family F10 and G11. A clear understanding of the expression pattern of microbial F10 and G11 under different culture conditions would facilitate better production and industrial application of xylanase. In this study, the fungal xylanase producer Aspergillus niger A09 was systematically investigated in terms of induced expression of xylanase F10 and G11. Results showed that carbon and nitrogen sources could influence xylanase F10 and G11 transcript abundance, with G11 more susceptible to changes in culture media composition. The most favorable carbon and nitrogen sources for high G11 and low F10 production by A. niger A09 were xylan (2%) and (NH4)2C2O4 (0.3%), respectively. Following cultivation at 33 °C for 60 h, the highest xylanase activity (1132 IU per gram of wet mycelia) was observed. On the basis of differential gene expression of F10 and G11, as well as their different properties, we deduced that the F10 protein initially targeted xylan and hydrolyzed it into fragments including xylose, after which xylose acted as the inducer of F10 and G11 gene expression. These speculations also accounted for our failure to identify conditions favoring the high production of F10 but a low production of G11.
Woon, J. S. K., E-mail: email@example.com; Murad, A. M. A., E-mail: firstname.lastname@example.org; Abu Bakar, F. D., E-mail: email@example.com [School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)
A cellobiohydrolase B (CbhB) from Aspergillus niger ATCC 10574 was cloned and expressed in E. coli. CbhB has an open reading frame of 1611 bp encoding a putative polypeptide of 536 amino acids. Analysis of the encoded polypeptide predicted a molecular mass of 56.2 kDa, a cellulose binding module (CBM) and a catalytic module. In order to obtain the mRNA of cbhB, total RNA was extracted from A. niger cells induced by 1% Avicel. First strand cDNA was synthesized from total RNA via reverse transcription. The full length cDNA of cbhB was amplified by PCR and cloned into the cloning vector, pGEM-T Easy. A comparison between genomic DNA and cDNA sequences of cbhB revealed that the gene is intronless. Upon the removal of the signal peptide, the cDNA of cbhB was cloned into the expression vector pET-32b. However, the recombinant CbhB was expressed in Escherichia coli Origami DE3 as an insoluble protein. A homology model of CbhB predicted the presence of nine disulfide bonds in the protein structure which may have contributed to the improper folding of the protein and thus, resulting in inclusion bodies in E. coli.
Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian
In this study, the role of citral to permeabilize the spores of Aspergillus niger and replace sodium azide in the bioconversion medium was studied. Further, characterization of glucose oxidase of spores was carried out by exposing both permeabilized and unpermeabilized spores to different pressures (1, 2, 2.7 kb) and temperatures (60, 70, 80, 90 degrees C). Unpermeabilized spores after exposure to high temperatures were permeabilized by freezing before using as catalyst in the bioconversion reaction. Results showed that citral permeabilized the spores and could inhibit spore germination in the bioconversion medium. Rate of reaction was significantly increased from 1.5 to 4.35 g/Lh which was higher than the commercial glucose oxidase 2g/Lh). Glucose oxidase activity of A. niger was resistant to pressure. However, pressure treatment could not permeabilize them. Behaviour of fresh and permeabilized spores to temperature varied significantly. Glucose oxidase activity of fresh spores exposed to high temperature was unaffected at 70 degrees C till 15 min and 84% of relative activity was retained even after 1h at 70 degrees C while permeabilized spore got inactivated at 70 degrees C for 15 min, which followed the same pattern as commercial glucose oxidase. Cellular membrane integrity was lost due to permeabilization by freezing which resulted in heat-inactivation of glucose oxidase when spores were permeabilized before heat treatment. Thus, glucose oxidase of spore remains heat stable when unpermeabilized and active while permeabilized and its reaction rate is higher than the commercial glucose oxidase.
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
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.
李杰; 吴婷; 马南; 王欣; 杨建乐; 李健友; 张会
's genome sequence of Aspergillus kawachii and encoding protein was 100% similar to acid protease of Aspergillus kawachii, and it was named as pepB. Furthermore Aspergilluse niger expression vector pSZHG-pepB was constructed and the homozygous transformation of homologous recombination at the glaA site was selected by Agrobacterium mediated transformation of Aspergillus niger CICC2462 By shaking flask fermentation, the product was studied by SDS-PAGE and the activity was detected, acid protease's characterization and stabilitywas studied. Experimental results showed that the pure homologous recombination strains had about 47 ku protein band which was found by SDS-PAGE and acid protease activity of fermentation product was 5 543 U·mL-1 which is 152 times of the activity of starting strain. By studying the acid protease's characterization and stability of this strain, we found that the enzyme optimum reaction temperature is 50℃, the optimal pH was 3.0, what's more, enzyme activity is stable when the pH is between 3.0 and 4.0 meanwhile the temperature is 4 ℃ or 25℃.
The cDNA of soluble human tumor necrosis factor receptorⅠ(sTNFRI) was inserted into fusion-protein expression plasmid pIGF of A. niger to construct fusion expression vector pHBC containing a KEX2 like protein processing site designed on the fusion position. Extracellular protease-deficient strain of A. niger 3.795-1-23 was transformed with pHBC. Positive clone was estimated by Southern hybridization. SDS-PAGE for protein produced by re-combinant strain showed the distinctive expression band. Western blotting indicated that the secreted protein had immunoactivity of sTNFRI.
Schachtschabel, Doreen; Arentshorst, Mark; Nitsche, Benjamin M
The Tup1-Cyc8 (Ssn6) complex is a well characterized and conserved general transcriptional repressor complex in eukaryotic cells. Here, we report the identification of the Tup1 (TupA) homolog in the filamentous fungus Aspergillus niger in a genetic screen for mutants with a constitutive expression...... of the agsA gene. The agsA gene encodes a putative alpha-glucan synthase, which is induced in response to cell wall stress in A. niger. Apart from the constitutive expression of agsA, the selected mutant was also found to produce an unknown pigment at high temperatures. Complementation analysis...
Asther, Michèle; Estrada Alvarado, Maria Isabel; Haon, Mireille; Navarro, David; Asther, Marcel; Lesage-Meessen, Laurence; Record, Eric
Among 15 Aspergillus strains, Aspergillus niger BRFM 131 was selected for its high chlorogenic acid hydrolase activity. The enzyme was purified and characterized with respect to its physico-chemical and kinetic properties. Four chromatographic steps were necessary to purify the protein to homogeneity with a recovery of 2%. Km of the chlorogenic acid hydrolase was estimated to be 10 microM against chlorogenic acid as substrate. Under native conditions, the protein presented a molecular mass of 170 kDa, and SDS-PAGE analysis suggested the presence of two identical 80 kDa subunits. Isoelectric point was 6.0; pH optimum for activity was determined to be 6.0 and temperature optima to be 55 degrees C. The N-terminal sequence did not present any homology with other cinnamoyl ester hydrolases previously described suggesting the purification of a new protein. The chlorogenic acid hydrolase was used successfully for the production of caffeic acid, which possesses strong antioxidant properties, from natural substrates specially rich in chlorogenic acid like apple marc and coffee pulp.
Mohammed Suleiman Zaroog
Full Text Available Different spectral probes were employed to study the stabilizing effect of various polyols, such as, ethylene glycol (EG, glycerol (GLY, glucose (GLC and trehalose (TRE on the native (N, the acid-denatured (AD and the thermal-denatured (TD states of Aspergillus niger glucoamylase (GA. Polyols induced both secondary and tertiary structural changes in the AD state of enzyme as reflected from altered circular dichroism (CD, tryptophan (Trp, and 1-anilinonaphthalene-8-sulfonic acid (ANS fluorescence characteristics. Thermodynamic analysis of the thermal denaturation curve of native GA suggested significant increase in enzyme stability in the presence of GLC, TRE, and GLY (in decreasing order while EG destabilized it. Furthermore, CD and fluorescence characteristics of the TD state at 71°C in the presence of polyols showed greater effectiveness of both GLC and TRE in inducing native-like secondary and tertiary structures compared to GLY and EG.
Bathoorn, Erik; Salazar, Natalia Escobar; Sepehrkhouy, Shahrzad; Meijer, Martin; de Cock, Hans; Haas, Pieter-Jan
Background: Aspergillus tubingensis is a black Aspergillus belonging to the Aspergillus section Nigri, which includes species that morphologically resemble Aspergillus niger. Recent developments in species determination have resulted in clinical isolates presumed to be Aspergillus niger being reclas
闫丽娟; 赵春雷; 谢振荣; 唐湘华; 黄遵锡
目的:筛选耐高温脂肪酶产生菌株并对其进行18SrDNA鉴定及系统进化树亲缘分析.方法:通过聚乙烯醇橄榄油乳化液方法对所选菌株的粗酶酶学性质进行研究并通过BLAST和MAGFA软件鉴定和聚类分析.结果:从云南省福贡县的榨油作坊土壤中筛选到一株耐高温产酸性脂肪酶的菌株NJY-1,对其粗酶酶学性质进行研究结果表明:该菌株酶促反应的最适作用DH为6.0, pH稳定性为3.0-8.0,最适作用温度为50℃,温度稳定性为35～60℃.该菌株通过18SrDNA鉴定及系统进化树分析,NJY-1与Aspergillus niger具有最紧密的亲缘关系,达到99%.结论:筛选到了1株耐高温脂肪酶产生菌株NJY-1,确定了其粗酶酶学性质和其亲缘关系.
The effect of microwave's radiation on seed viability of three different oilseed crops, spores of Aspergillus niger and quality of extracted oil from treated seeds over various exposure times was evaluated. The seeds were exposed to 2450 MHz. at five different power levels of 0, 100, 200, 400, 600 and 800 W for two exposure times of three and five minutes. At a given time, a direct negative relationship between seed viability and microwave's radiation power level was detected. Substantial var...
Indoor airborne fungi have been implicated in human health problems, damage to building materials, books, clothes and stored foods, which effected by different ecological factors. Aspergillus niger and Cladosporium sphaerospermum are the most dominant indoor airborne fungi were obtained from our previous study. The effect of normal indoor conditions (Temperature and Relative Humidity) on their growth was studied. Including their nutrients growth requirements. The PDA medium was the appropriat...
Inoue, Kotomi; Takahashi, Yui; Obara, Ken; Murakami, Shuichiro
Cell wall-associated β-xylosidase was isolated from Aspergillus niger E-1 and identified as XlsIV, corresponding to the extracellular enzyme XlnD reported previously. xlsIV was transcribed only in the early cultivation period. Cell wall-associated enzyme activity gradually decreased, but extracellular activity increased as the strain grew. These results indicate that XlsIV (XlnD) was secreted into culture after localizing at cell wall.
Taylor-Edmonds, Lizbeth; Lichi, Tovit; Rotstein-Mayer, Adi; Mamane, Hadas
The use of Aspergillus niger (A. niger) fungal spores as challenge organism for UV reactor validation studies is attractive due to their high UV-resistance and non-pathogenic nature. However A. niger spores UV dose-response was dependent upon sporulation conditions and did not follow the Bunsen-Roscoe Principle of time-dose reciprocity. Exposure to 8 h of natural sunlight for 10 consecutive days increased UV resistance when compared to spores grown solely in dark conditions. Application of 250 mJ cm(-2) at high irradiance (0.11 mW cm(-2)) resulted in a 2-log inactivation; however, at low irradiance (0.022 mW cm(-2)) a 1-log inactivation was achieved. In addition, surface electron microscopy (SEM) images revealed morphological changes between the control and UV exposed spores in contrast to other well accepted UV calibrated test organisms, which show no morphological difference with UV exposure.
Li, Fei; Xie, Jingcong; Zhang, Xuesong; Zhao, Linguo
In an attempt to shift the optimal pH of the xylanase B (XynB) from Aspergillus niger towards alkalinity, target mutation sites were selected by alignment between Aspergillus niger xylanase B and other xylanases that have alkalophilic pH optima that highlight charged residues in the eight-residues-longer loop in the alkalophilic xylanase. Multiple engineered XynB mutants were created by site-directed mutagenesis with substitutions Q164K and Q164K+D117N. The variant XynB-117 had the highest optimum pH (at 5.5), which corresponded to a basic 0.5 pH unit shift when compared with the wild-type enzyme. However, the optimal pH of the XynB- 164 mutation was not changed, similar to the wild type. These results suggest that the residues at positions 164 and 117 in the eight-residues-longer loop and the cleft's edge are important in determining the pH optima of XynB from Aspergillus niger.
Full Text Available For the purpose of finding a suitable available inducer in combination with starvation, carbohydrate mixtures from triticale was used as inducers and compared with well-known amylase inducers in fungi. Carbohydrate mixtures from triticale induced production of amylase cocktail (α-amylase and glucoamylase in Aspergillus niger, unlike induction with well-known inducers which induce only glucoamylase, showed by zymogram and TLC analysis of carbohydrates mixtures before and after fermentations. Glucoamylase production by A. niger was highest in the presence of extract obtained after autohydrolysis of starch from triticale (95.88 U/mL. Carbohydrate mixtures from triticale induced production of α-amylase in A. oryzae. More α-amylase isoforms were detected upon using complex carbohydrate mixture, compared to induction with maltose or starch. The 48 h induction was the most efficient by using triticale extract (101.35 U/mL. Carbohydrates from triticale extracts can be used as very good cheap amylase inducers. Triticale, still not fully utilized, could be taken into consideration as the inducer in amylase production by Aspergillus sp, such a way it could be used as sole substrate in fermentation. [Projekat Ministarstva nauke Republike Srbije, br. 172048
Rawat, Rekha; Kumar, Sunil; Chadha, Bhupinder Singh; Kumar, Dinesh; Oberoi, Harinder Singh
Endoglucanase (EG) from Aspergillus niger HO was sequentially purified through ultrafiltration, ion exchange and size exclusion chromatography to homogeneity, with an overall recovery of 18 %. The purified EG was a monomeric protein with a molecular weight of about 55 kDa. The enzyme was optimally active at pH 3.5 and 70 °C with a half life (t1/2) of 3 h and Km value of 2.5 mg/ml. Metal ions, such as Ca(2+) and Co(2+) helped in enzyme induction, while Hg(2+) and Cu(2+) strongly inhibited the enzyme activity. Peptide mass fingerprinting results revealed that the purified EG is a novel enzyme that belongs to family 12 of glycoside hydrolase (GH12). Molecular docking studies indicated the presence of Glu116 and Glu204 as important determinant residues for the functional interaction with carboxymethylcellulose and showed hydrogen bonding with Asp99, Glu116, Glu204 and hydrophobic interactions with Trp22, Val58, Tyr61, Phe101, Met118, Trp120, Pro129, Ile130, Thr160 and Phe206. Hydrolysis of 2 % CMC with purified acidothermophilic EG at its optimum temperature and pH resulted in complete hydrolysis within 2 h yielding 18 % cellotriose, 72 % cellobiose and 10 % glucose as evident from HPLC analysis. In comparison to most of the EGs reported in literature, EG from A. niger HO exhibited higher thermostability. The acidothermophilic nature of this enzyme makes it potentially useful for industrial applications.
Studies on simultaneous saccharification and fermentation (SSF) of wheat bran flour, a grain milling residue as the substrate using coculture method were carried out with strains of starch digesting Aspergillus niger and nonstarch digesting and sugar fermenting Kluyveromyces marxianus in batch fermentation. Experi-ments based on central composite design (CCD) were conducted to maximize the glucose yield and to study the effects of substrate concentration, pH, temperature, and enzyme concentration on percentage conversion of wheat bran flour starch to glucose by treatment with fungal α-amylase and the above parameters were optimized using response surface methodology (RSM). The optimum values of substrate concentration, pH, temperature, and enzyme concentration were found to be 200 g/L, 5.5, 65℃ and 7.5 IU, respectively, in the starch saccharification step. The effects of pH, temperature and substrate concentration on ethanol concentration, biomass and reducing sugar concentration were also investigated. The optimum temperature and pH were found to be 30℃ and 5.5, respectively. The wheat bran flour solution equivalent to 6% (w/V) initial starch concentration gave the highest ethanol concentration of 23.1 g/L after 48 h of fermentation at optimum conditions of pH and temperature. The growth kinetics was modeled using Monod model and Logistic model and product formation kinetics using Leudeking-Piret model. Simultaneous saccharificiation and fermenta-tion of liquefied wheat bran starch to bioethanol was studied using coculture of amylolytic fungus A. niger and nonamylolytic sugar fermenting K. marxianus.
Full Text Available BACKGROUND: Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s that evolve in direct response to selection, enhancing the organism's fitness. "Evolution Canyon" (EC in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric "African" slope (AS receives 200%-800% higher solar radiation than the north-facing, temperate, shady and mesic "European" slope (ES, 200 meters apart. Thus, solar ultraviolet radiation (UVR is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. METHODOLOGY/PRINCIPAL FINDINGS: We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin
肖长清; 戚天胜; 赵海
从大曲中分离到了1株降解生淀粉能力较强的黑曲霉Aspergillus niger(6#).固体发酵酶活可达2 461 U/g,RDA值为21.47%;液体发酵酶活可达353 U/mL,RDA值为20.30%.以6#菌为实验材料,进一步考察了氮源、碳源及pH对生淀粉糖化酶形成的影响.实验结果表明,无机氮源NaNO3较有机氮源蛋白胨更有利于生淀粉糖化酶的形成;pH是影响生淀粉糖化酶形成的重要因素,低pH会阻遏生淀粉糖化酶的形成;玉米粉和麦芽糖较其它碳源更有利于生淀粉糖化酶的形成.图4表2参12
周宁; 赵晓璐; 谢庆武
采用硝酸铝显色法、三氯化铝显色法和紫外分光光度法对甘蔗叶内生真茵Aspergillus niger GZ-4总黄酮含量的测定结果进行比较.结果表明:硝酸铝显色法和三氯化铝显色法不适用于GZ-4菌株总黄酮含量的测定;采用紫外分光光度法,以芦丁为对照品,在0～0.048 mg·mL 1范围内吸光度与浓度的线性关系良好(R=0.9999),平均加样回收率为101.4％,RSD为1.8％(n=5).该方法可以简便、快速、准确地测定GZ-4菌株总黄酮含量.
Full Text Available Primary cutaneous aspergillosis is a rare entity, usually caused by A. fumigatus and A. flavus . Here, we present such a case, manifested by ulceration due to A. niger, which remained undiagnosed for a prolonged period. The immunological status was intact, although the patient had associated severe fungal infection. Recurrence of the lesion occurred despite repeated anti-fungal therapies. Anti fungal testing was done based on the broth dilution (M-38A, NCCLS, USA method. The culture isolate was found to be sensitive to fluconazole and amphotericin B. Continuation of antifungal therapy improved the symptoms, reducing the size of the lesion.
Full Text Available Introduction: Pectinase enzyme is one of the most important industrial enzymes which isolated from a wide variety of microorganisms such as bacteria and filamentous fungi. This enzyme has been usually used in the fruit and textile industry. In this study, the isolation and optimization of pectinase-producing fungi on decaying rotten fruits were studied. Materials and methods: Isolation and screening of pectinase producing fungi performed through plate culture on pectin medium and staining with Lugol's iodine solution. The best strains were identified by ITS1, 4 sequencing as Aspergillus fumigatus, Rhizopus oryzae, Penicilium chrysogenum. The enzyme production was optimized by application of the five factorial design, each at three levels. These factors are carbon sources (whey, glucose and stevia, ammonium sulfate, manganese sulfate, temperature, and pH. Pectinase concentration was measured by the Miller method. Results: The results indicate that optimum condition for enzyme production for three fungi strains was obtained at 32 °C, pH = 6, 3g / L manganese sulfate, 2.75g / L of ammonium sulfate and 10g / L of each carbon source. The best experiment in obtaining the optimum enzyme contained 1.328 mg / ml of glucose for Aspergillus niger 1.284 and 1.039 mg / ml of whey for Rhizopus oryzae and Penicilium chrysogenum. Molecular weight of enzyme was about 40 and 37 kDa which was obtained by SDS- PAGE. Discussion and conclusion: The results indicate that three strains could grow in a wide range of carbon source, pH and temperature, which could be a good candidate for industrial application.
徐丹; 孙秀兰; 李永仙; 杨振东; 王洪新
目的 研究黑曲霉对黄曲霉生长、产毒的抑制作用及对AFB1的降解作用.方法 将黑曲霉分别与黄曲霉、AFB1共同培养,定期测定培养液pH、菌丝体干重、黄曲霉孢子数、AFB1含量.结果 黑曲霉与黄曲霉混合培养时,黄曲霉孢子数、AFB1含量均比单独培养的低,2组之间差异有统计学意义 (P＜0.05),抑制率达到68.06%～91.52%;加入黑曲霉后,AFB1含量降低,实验组与对照组之间差异有统计学意义 (P＜0.05),降解率为46.19%.结论 黑曲霉既能抑制黄曲霉生长、产毒,又能降解AFB1.%Objective To study the influence of Aspergillus niger on the growth of Aspergillusflavus and degrada-tion of AFB1. Method Aspergillus niger was co-cultured with Aspergillus flavu s and AFB1, respectively; pH, dry weight of mycelium, spores of Aspergillus flavus and content of AFB1 were determined every 3 days. Result Compared with the control group, the number of Aspergillusflavus spores and content of AFB1 were much less in competitive situation. There was a significant difference between the two groups (P ＜0.05 ) and the rate of inhibition was 68.06％ to 91.52％; more-over, AFB1 was reduced when Aspergillus niger was inoculated, with is a significant difference between the two groups (P ＜ 0.05 ), and the rate of degradation was 46.19％. Conclusion Aspergillus niger not only can inhibit the growth of Aspergil-lus flavus and production of AFB1, but also degrade AFB1.
李乐; 胡以华; 顾有林; 陈卫
The reflection spectra of Aspergillus niger spores within the waveband of 2.5-15 μm were measured by squash method. Based on the measured data, complex refractive index of Aspergillus niger spores within the waveband of 2.5-15μm were calculated by using Krames-Kronig (K-K) relationship. Then, the mass extinction coefficient of Aspergillus niger spores within the waveband of 2.5-15μm were obtained by utilizing Mie scattering theory, and the results were analyzed and discussed. The average mass extinction coefficient of Aspergillus niger spores is 0.68 m2/g in the range of 2.5-15μm, and the average mass extinction coefficient decreases monotonically with the particle size increases. Compared with common inorganic compounds, Aspergillus niger spores possesses a good extinction performance within the waveband of 2.5-15 μm, and the requirement of particle size is relative wide in a certain extinction performance.%采用压片法对黑曲霉孢子2.5~15μm波段的反射光谱进行了测量。针对采集的光谱数据，利用Krames-Kronig(K-K)关系对黑曲霉孢子2.5~15μm波段的复折射率进行了计算。然后,根据Mie散射理论求出了2.5~15μm波段黑曲霉孢子质量消光系数，并对结果进行了分析和讨论。分析结果表明，在粒径r=1.2μm时，黑曲霉孢子在2.5~15μm波段的平均质量消光系数为0.68 m2/g，随着粒径的增大，平均质量消光系数单调减小；与常见无机物相比，黑曲霉孢子在2.5~15μm波段具有较好的消光性能，而且在保证一定消光性能的情况下，黑曲霉孢子的粒径尺寸要求相对较宽。
Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Wang, Ke; Tang, Lei; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui
To solve the problem of extraction wastewater in citric acid industry, an integrated citric acid-methane fermentation process was proposed. In the integrated process, extraction wastewater was treated by mesophilic anaerobic digestion and then reused to make mash for the next batch of citric acid fermentation. In this study, an Aspergillus niger mutant strain exhibiting resistance to high metal ions concentration was used to eliminate the inhibition of 200 mg/L Na(+) and 300 mg/L K(+) in anaerobic digestion effluent (ADE) and citric acid production increased by 25.0 %. Air stripping was used to remove ammonium, alkalinity, and part of metal ions in ADE before making mash. In consequence, citric acid production was significantly improved but still lower by 6.1 % than the control. Results indicated that metal ions in ADE synergistically inhibited the activity of glucoamylase, thus reducing citric acid production. When 130 U/g glucoamylase was added before fermentation, citric acid production was 141.5 g/L, which was even higher than the control (140.4 g/L). This process could completely eliminate extraction wastewater discharge and reduce water resource consumption.
Full Text Available The aims of this research were to know the concentration of arrowroot flour which produced the highest reducing sugar in saccharification process by A. niger, as well as to know the efficiency of ethanol production by Z. mobilis. The framework of this research was the increasing needs of ethanol; meanwhile ethanol could be obtained from the fermentation arrowroot. This research was carried out in two stages. In the saccharification stage, there are four concentrations, namely: 10%, 20%, 30% and 40%, and A. niger concentration of 10% (v/v for each arrowroot flour concentration with spores amount 3,3x106/mL. The parametric measurement includes: starch concentration in the starting day and the sixth day, while the reducing sugar concentration and pH was measured every 24 hours during 6 days. In the ethanol fermentation, Z. mobilis concentration have been used 10% (v/v with cells amount 5,1x107/mL and it was used in solution product of arrowroot starch saccharification and parametric measurement carried out during 72 hours includes: ethanol and reducing sugar concentration and the growth of Z. mobilis cells. The data resulted from parametric measurement. The result of the research showed that arrowroot flour concentration of 10% produced the highest reducing sugar in process of saccharification with reducing sugar concentration was 1,230 g/100 mL in four days and the efficiency of ethanol production by Z. mobilis during 72 hours was 83,03%.
Full Text Available This study examines the bioleaching of municipal solid waste incineration fly ash by Aspergillus niger, and its effect on the fungal morphology, the fate of the ash particles, and the precipitation of metallic salt crystals during bioleaching. The fungal morphology was significantly affected during one-step and two-step bioleaching; scanning electron microscopy revealed that bioleaching caused distortion of the fungal hyphae (with up to 10 μm hyphae diameter and a swollen pellet structure. In the absence of the fly ash, the fungi showed a linear structure (with 2–4 μm hyphae diameter. Energy-dispersive X-ray spectroscopy and X-ray diffraction confirmed the precipitation of calcium oxalate hydrate crystals at the surface of hyphae in both one-step and two-step bioleaching. Calcium oxalate precipitation affects bioleaching via the weakening of the fly ash, thus facilitating the release of other tightly bound metals in the matrix.
Zheng, X X; Chen, R S; Shen, Y; Yin, Z Y
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.
Full Text Available Agricultural wastes, such as coconut meal and kernel palm meal can be used to fulfill the need of feed for ruminants or monogastrics. Fermentation technology using Aspergillus niger has been reported allow to increase their nutritive value. Isolation of the asporogenous strain which could spored at room temperature but could not spored at 37oC is expected to sole the fermentation of spores in the fermentation product. The spore formation of mutants at the fourth day incubation time (10% was less than the wild type (100%. The variance analysis of protein content in vitro Dry Matter Digestibility (IVDMD and in vitro Protein Digestibility (IVPD showed that the kind of mutants were interacted with the incubation time (P<0,01. The highest protein content of coconut meal was obtained from E27 mutant (33.0%, kernel palm meal was obtained from E14 mutant (31.4% at the fourth day of incubation time. The highest IVDMD of coconut meal (62.1%, kernel palms meal (61.8% at the fourth day incubation time and from all E27 mutant. The highest IVPD of coconut meal was obtained from E27 mutant (20.49% at the fourth day incubation time, kernel palm meal was obtained from E27 mutant (18.66% at the fourth days incubation time.
HAN Shengfang; GU Juntao; XIAO Kai
Using the cotyledon of white clover as explants,the transgenic white clover lines ectopic expression of the PhyA gene were established based on Agrobacterium tumefaciens-mediated transformation method.It was found that the tested transgenic lines were all Polymerase Chain Reaction (PCR) positive.The transgenic lines 1 to 4 were used for further Southern blot and Northern blot analysis.The lines 1 and 3 with higher level of PhyA expression were used to assay the phytase activities in root and its intercellular space.When the phytate was the sole phosphorus source,the phytase activities in root in lines 1 and 3 were 31.43% and 44.76% higher than those in control (CK),respectively.Meanwhile,the phytase activities in the root intercellular space in lines 1 and 3 were 3.3-fold and 5.12-fold higher than those in CK,respectively.The phosphorus concentration of plants,the accumulative P amount per plant,plant fresh weight,and plant dry weight were all much higher in lines 1 and 3 than in CK.Thus,it is clearly shown that ectopic expression of Aspergillus niger PhyA gene could significantly increase the ability for white clover to utilize organic phosphate under inorganic phosphate (Pi)-deficient condition.
Full Text Available 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.
Edwinoliver, N G; Thirunavukarasu, K; Naidu, R B; Gowthaman, M K; Kambe, T Nakajima; Kamini, N R
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.
Mata-Gómez, Marco; Mussatto, Solange I; Rodríguez, Raul; Teixeira, Jose A; Martinez, Jose L; Hernandez, Ayerim; Aguilar, Cristóbal N
Gallic acid production in a batch bioreactor was evaluated using as catalytic material the mouldy polyurethane solids (MPS) obtained from a solid-state fermentation (SSF) bioprocess carried out for tannase production by Aspergillus niger GH1 on polyurethane foam powder (PUF) with 5 % (v/w) of tannic acid as inducer. Fungal biomass, tannic acid consumption and tannase production were kinetically monitored. SSF was stopped when tannase activity reached its maximum level. Effects of washing with distilled water and drying on the tannase activity of MPS were determined. Better results were obtained with dried and washed MPS retaining 84 % of the tannase activity. Maximum tannase activity produced through SSF after 24 h of incubation was equivalent to 130 U/gS with a specific activity of 36 U/mg. The methylgallate was hydrolysed (45 %) in an easy, cheap and fast bioprocess (30 min). Kinetic parameters of tannase self-immobilized on polyurethane particles were calculated to be 5 mM and 04.1 × 10(-2) mM/min for K M and V max, respectively. Results demonstrated that the MPS, with tannase activity, can be successfully used for the production of the antioxidant gallic acid from methyl-gallate substrate. Direct use of PMS to produce gallic acid can be advantageous as no previous extraction of enzyme is required, thus reducing production costs.
Full Text Available Aspergillus niger FETL FT3, a local extracellular tannase producer strain that was isolated from one of dumping sites of tannin-rich barks of Rhizophora apiculata in Perak, Malaysia. This fungus was cultivated in 250 mL Erlenmeyer flask under submerged fermentation system. Various physical parameters were studied in order to maximize the tannase production. Maximal yield of tannase production, that is, 2.81 U per mL was obtained on the fourth day of cultivation when the submerged fermentation was carried out using liquid Czapek-Dox medium containing (percent; weight per volume 0.25% NaNO3, 0.1% KH2PO4, 0.05% MgSO4 ·7H2O, 0.05% KCl, and 1.0% tannic acid. The physical parameters used initial medium pH of 6.0, incubation temperature of 30∘C, agitation speed of 200 rpm and inoculums size of 6×106 spores/ ml. This research has showed that physical parameters were influenced the tannase production by the fungus with 156.4 percent increment.
Tanokura, M; Sasaki, H; Muramatsu, T; Iwata, S; Hamaya, T; Takizawa, T; Takahashi, K
Proteinase A from Aspergillus niger var. macrosporus is a non-pepsin-type acid proteinase, whose catalytic residues and mechanism remain to be elucidated. A new form of proteinase A crystals more suitable for crystallography than that obtained previously was prepared from an ammonium sulfate solution at pH 3.5 by the hanging-drop vapor diffusion method. The space group of the crystals was P2(1)2(1)2(1), with unit cell dimensions of a = 69.75 +/- 0.06 A, b = 87.55 +/- 0.05 A, and c = 60.83 +/- 0.04 A. On the assumption of two enzyme molecules per asymmetric unit, the calculated volume to unit protein mass ratio (Vm) was 2.08 A3/Da. By assuming the specific volume to be 0.74 cm3/g, the solvent content (Vso1) was estimated to be 41%, i.e., much larger than that of the crystal form obtained previously at pH 2.0 (Vso1 = 26%). Diffraction data were collected up to a resolution higher than 1.6 A, using the Weissenberg camera for macromolecular crystallography with synchrotron radiation.
Full Text Available The thermostability of absolutely purified xylanase from Aspergillus niger DFR-5 was improved using polyols. Supplementation of sorbitol at 2M concentration was found to increase the half-life and D-value of xylanase at elevated temperatures (45-70ºC. Thermodynamic parameters associated with the process were analyzed revealing that the stability at higher temperatures was due to the increased enthalpy (∆Hº and free energy (∆Gº change of enzyme denaturation in the presence of sorbitol. The negative values of ∆Sº (-150.093 Jmol-1K-1 at 70ºC clearly indicated that enzyme underwent a significant process of aggregation during denaturation. The enzyme required divalent cations for maximum activity and inhibited by chelator. The diminution of activity by various thiol-binding agents and enhancement by reducing agents like β-ME confirmed the essentiality of cysteine for catalysis. The enzyme had a half-life and D-value of 277 and 921 days when stored at 4 ºC.
Full Text Available In this work, a protocol for the formulation of an enzyme concentrated product to be applied in fruit juice treatment is described. Downstream processing conditions for the recovery and concentration of pectinases produced by the new strain Aspergillus niger LB-02-SF in solid state cultivation were assessed. The solid-liquid ratio in the extraction step of pectinases recovery from the cultivated media was evaluated and the highest activity was obtained with a solid-liquid ratio of 1:10. The crude extract was concentrated by ultrafiltration and the total pectinase (TP activity was 73.6-fold concentrated in relation to the crude extract, and a final TP titer of 663 U mL–1 was obtained with 73.7% of recovery yield. KCl and different glycerol concentrations were added to the concentrated extract and the stability of pectinases during the storage at 5°C for 59 weeks was tested. The formulation with 50% w/w glycerol was applied to the treatment of apple and grape juices and the results of these tests were statistically comparable to those obtained with two high-quality commercial preparations.
Kyung Hoon Chang
Full Text Available Rb1-hydrolyzing β-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,β-(1→6-glucoside of ginsenoside Rb1 to generate ginsenoside Rd and Rg3, and hydrolyzed 3-C,β-(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.
Olayinka Quadri Adio
Full Text Available In this study mould strains screened and molecularly identified as Aspergillus niger F7-02 was used to produced extracellular lipase in Solid State Fermentation (SSF process. Different agricultural residues were combined in different ratios as carbon, nitrogen and elemental sources in the solid culture medium. The optimization of the culture medium was carried out for such parameters as incubation time (24 h - 96 h, inoculum concentration (0.5 – 3.0%, w/v, initial moisture content (40 – 70%, w/v, and initial pH (6 – 8 for maximum yield. The maximum lipase activity of 76.7 U/ml was obtained with a medium containing rice bran (RB, palm kernel cake (PKC, groundnut cake (GNC and starch (S at the ratio of 5:5:3:1 (%w/w with optimum conditions of 60% moisture, 1% inoculum and a pH of 7.0 with an incubation temperature of 30 oC and incubation time of 72 h.
Gajera, H P; Katakpara, Zinkal A; Patel, S V; Golakiya, B A
The study was conducted to examine the antioxidant enzymes induced by Trichoderma viride JAU60 as initial defense response during invasion of rot pathogen Aspergillus niger Van Tieghem in five groundnut varieties under pot culture. Seed treatment of T. viride JAU60 reduced 51-58% collar rot disease incidence in different groundnut varieties under pathogen infected soil culture. The activities of the antioxidant enzymes, viz., superoxide dismutase (SOD, EC 126.96.36.199), guaiacol peroxidase (GPX, EC 188.8.131.52) and ascorbate peroxidase (APX, EC 184.108.40.206), elevated in response to pathogen infection, in higher rate by tolerant varieties (J-11 and GG-2) compared with susceptible (GAUG-10, GG-13, GG-20) and further induced by T. viride treatment. Trichoderma treatment remarkably increased the 2.3 fold SOD, 5 fold GPX and 2.5 fold APX activities during disease development in tolerant varieties and the same was found about 1.2, 1.5 and 2.0 folds, respectively, in susceptible varieties. Overall, T. viride JAU60 treated seedlings (T3) witnessed higher activities of SOD (1.5 fold), GPX (3.25 fold) and APX (1.25 fold) than pathogen treatment (T2) possibly suggest the induction of antioxidant defense response by Trichoderma bio-controller to combat oxidative burst produced by invading pathogen.
van Munster, Jolanda M; Sanders, Peter; ten Kate, Geralt A; Dijkhuizen, Lubbert; van der Maarel, Marc J E C
The abundant polymer chitin can be degraded by chitinases (EC 220.127.116.11) and β-N-acetyl-hexosaminidases (EC 18.104.22.168) to oligosaccharides and N-acetyl-glucosamine (GlcNAc) monomers. Kinetic characterization of these enzymes requires product quantification by an assay method with a low detection limit, preferably compatible with the use of native, non-labeled substrates. Here we report a quantitative HPAEC-PAD method that allows fast separation of chitin oligosaccharides (COS) ranging from (GlcNac)1-6 at detection limits of 1-3 pmol and a linear range of 5-250 pmol. Quantification under intra- and interday precision conditions was performed with 2.1-5.4% relative standard deviation (RSD) and 1.2-10.3% RSD, respectively. This method was successfully used for the determination of the kinetic parameters of the Aspergillus niger chitinase CfcI with native COS. CfcI was recently shown to release GlcNAc from the reducing end of COS, a new activity for fungal chitinases. A Carbohydrate Binding Module of family 18 (CBM18) is inserted in the CfcI catalytic domain. Site directed mutagenesis was used to assess the functionality of this CfcI-CBM18: four of its key amino acids were replaced by glycine residues, yielding CfcISYNF. Comparison of the kinetic parameters of CfcI and CfcISYNF confirmed that this CBM18 is functionally involved in catalysis.
Li, Zhen; Bai, Tongshuo; Dai, Letian; Wang, Fuwei; Tao, Jinjin; Meng, Shiting; Hu, Yunxiao; Wang, Shimei; Hu, Shuijin
Phosphate solubilizing fungi (PSF) have huge potentials in enhancing release of phosphorus from fertilizer. Two PSF (NJDL-03 and NJDL-12) were isolated and identified as Penicillium oxalicum and Aspergillus niger respectively in this study. The quantification and identification of organic acids were performed by HPLC. Total concentrations of organic acids secreted by NJDL-03 and NJDL-12 are ~4000 and ~10,000 mg/L with pH values of 3.6 and 2.4 respectively after five-days culture. Oxalic acid dominates acidity in the medium due to its high concentration and high acidity constant. The two fungi were also cultured for five days with the initial pH values of the medium varied from 6.5 to 1.5. The biomass reached the maximum when the initial pH values are 4.5 for NJDL-03 and 2.5 for NJDL-12. The organic acids for NJDL-12 reach the maximum at the initial pH = 5.5. However, the acids by NJDL-03 continue to decrease and proliferation of the fungus terminates at pH = 2.5. The citric acid production increases significantly for NJDL-12 at acidic environment, whereas formic and oxalic acids decrease sharply for both two fungi. This study shows that NJDL-12 has higher ability in acid production and has stronger adaptability to acidic environment than NJDL-03.
Safaradeen Olateju Kareem
Full Text Available The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v Irvingia gabonensis powder, 15% (v/v partially purified lipase, 2.5% (v/v glutaraldehyde, and 3 : 1 (v/v ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug−1 was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg−1 and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established.
Ottenheim, Christoph; Verdejo, Carl; Zimmermann, Wolfgang; Wu, Jin Chuan
Palm oil empty fruit bunches (EFB) is an abundant and cheap lignocellulose material in Southeast Asia. Its use as the sole medium for producing lignocellulose-hydrolyzing enzymes would increase its commercial value. A newly isolated Aspergillus niger DSM 26641 was investigated for its capability of producing hemicellulases in EFB hydrolysate obtained by treatment with pressurized hot water (1-20%, w/v) at 120-180°C in a 1 L Parr reactor for 10-60 min. The optimal hydrolysate for the fungal growth and endoxylanase production was obtained when 10% (w/v) of empty fruit bunch was treated at 120°C or 150°C for 10 min, giving an endoxylanase activity of 24.5 mU ml(-1) on RBB-Xylan and a saccharification activity of 5 U ml(-1) on xylan (DNS assay). When the hydrolysates were produced at higher temperatures, longer treatment times or higher biomass contents, only less than 20% of the above maximal endoxylanase activity was detected, possibly due to the higher carbohydrate concentrations in the medium. Transcriptome analysis showed that 3 endoxylanases (expression levels 59-100%, the highest level was set as 100%), 2 β-xylosidases (4%), 4 side chain-cleaving arabinofuranosidases (1-95%), 1 acetyl xylan esterase (9%) and 2 ferulic acid esterases (0.3-9%) were produced together.
Wang, Shu-Yang; Jiang, Bo-Ling; Zhou, Xiang; Chen, Ji-Hong; Li, Wen-Jian; Liu, Jing; Hu, Wei; Xiao, Guo-Qing; Dong, Miao-Yin; Wang, Yu-Chen
The aim of this study was to evaluate and validate the efficiency of 12C6+ irradiation of Aspergillus niger (A. niger) or mutagenesis via mixed Trichoderma viride (T. viride) culturing as well as a liquid cultivation method for cellulase production via mixed Trichoderma reesei (T. reesei) and A. niger culture fermentation. The first mutagenesis approach was employed to optimize yield from a cellulase-producing strain via heavy-ion mutagenesis and high-throughput screening, and the second was to effectively achieve enzymatic hydrolysis of cellulase from a mixed culture of mutant T. viride and A. niger. We found that 12C6+-ion irradiation induced changes in cellulase biosynthesis in A. niger but had no effect on the time course of the synthesis. It is notable that the exoglucanases (CBH) activities of A. niger strains H11-1 and H differed (6.71 U/mL vs. 6.01 U/mL) and were significantly higher than that of A. niger mutant H3-1. Compared with strain H, the filter paper assay (FPA), endoglucanase (EG) and β-glucosidase (BGL) activities of mutant strain H11-1 were increased by 250.26%, 30.26% and 34.91%, respectively. A mixed culture system was successfully optimized, and the best ratio of T. reesei to A. niger was 5:1 for 96 h with simultaneous inoculation. The BGL activity of the mixed culture increased after 72 h. At 96 h, the FPA and BGL activities of the mixed culture were 689.00 and 797.15 U/mL, respectively, significantly higher than those of monocultures, which were 408.70 and 646.98 U/mL for T. reesei and 447.29 and 658.89 U/mL for A. niger, respectively. The EG activity of the mixed culture was 2342.81 U/mL, a value that was significantly higher than that of monocultures at 2206.57 U/mL for T. reesei and 1727.62 U/mL for A. niger. In summary, cellulose production and hydrolysis yields were significantly enhanced by the proposed combination scheme.
The peel of Citrus changshan-huyou, coupled with wheat bran, could be utilized by Aspergillus niger P-6021 in slurry-state fermentation to produce pectinase with suitable enzyme composition for application in apple juice processing. The production of pectinase is improved by additional nitrogen source substances and mineral supplements. The ratio of carbon source substances to nitrogen source substances in the medium also has significant effect on the pectinase production by A. niger P-6021 in slurry-state fermentation. In the optimized medium 30℃. The crude pectinase shows significant effect to improve the yield and clarification of apple juice.
Ravi Kumar Gundampati
Full Text Available A.niger Rnase was designed from ACTBIND (PDB ID: 3D3Z. Yeast actin-human gelsolin segment 1 complex (PDB ID: 1YAG was used as template for L. donovani actin protein for 3D model in Modeller9v8. These models were testified by PROCHECK, ERRAT, WHAT-IF, PROSA2003 and VERIFY-3D. All evidences suggest that the geometric quality of the backbone conformation, energy profile, residue interaction and contact of the structures were well within the limits of reliable structures. The interaction energy of docking was calculated using the HEX server. Etotal and calculated RMSD values were -1.902, -9.323 kcal moL-1 and 0.402 Ã , respectively. The study presented here has an advantage to design molecules that may have antileishmanial activity.
Full Text Available Citric acid production by A.niger, isolated from the microflora of Iran, has been investigated in liquid and semi-solid states using growth media with different compositions. In 2% media made of Rocheh grape pomace or sabouraud dextrose, the yield of citric acid production was 0.7 g per Kg of the pomace; and the yield decreased by 50% in 2% saghal solian grape pomace medium. However, in 40% (W/W saghal solian semi-solid medium containing 3% methanol, the yield of citric acid production has improved to 80 g per Kg of pomace in stationary mode of production and to 120 g per Kg of pomace in the rolling mode of fermentation.
Umbreen, Huma; Zia, Muhammad Anjum; Rasul, Samreen
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 (K(m), Vmax, Kcat and Kcat/K(m)) 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 thermally stable and the enthalpy and free energy showed an increase with increase in temperature and ΔS* was highly negative proving the enzyme from A. niger EMS-150-F resistant to temperature and showing a very little disorderliness.
ZHU Xingguo; QIU Runxiang; LIU Li; TANG Guomin
CCAAT-binding proteins AngCP1 and AngCP2 of Aspergillus niger binding to DC(- 489- - 414 bp)and PC(- 390～ - 345 bp)of A.Niger glaA gene were respectively purified by 20 % ～ 40 % saturated ammonium sulfate,gel filtration,Heparin SepharoseC1-6B chromatography and DNA sequence-specific affinity chromatography.Gel filtration and SDS-PAGE revealed that both AngCP1 and AngCP2 were of 120 kD,comprised of two suhunits of 34 kD and 50 kD.Western blot showed that the 34 kD subunits of both AngCP1 and AngCP2 cross-reacted specifically with the anti-AngHAPC antiserum.Further electrophoretic mobility shift assay identified that AngCP1 and AngCP2 were the same protein,designated AngCP.Southwestern blot showed that the affinity of the 34 kD subunit to DC was stronger than that of the 50 kD subunit to PC.These results suggested that interaction between AngCP,DC and PC plays an important role in the regulation of transcription of Aspergillus niger glaA gene.
HIDROLISIS ENZIMATIK MINYAK IKAN UNTUK PRODUKSI ASAM LEMAK OMEGA-3 MENGGUNAKAN LIPASE DARI Aspergillus niger [Enzymatic Hydrolysis of Fish Oil for Production of Omega-3 Fatty Acids Using Lipase Derived from Aspergillus niger
Full Text Available Fish oil is the source of important fatty-acid, especially polyunsaturated fatty acid (PUFA omega-3, such as eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. Lipase catalysis activity of Aspergillus niger is low when it is used in fish oil hydrolysis. The activity of the lipase can be increased by adding organic solvent such as hexane into the media. This research aimed to determine temperature, pH and amount of water which produce the highest degree of hydrolysis of fish oil in the presence of hexane. Correlation between the highest degree of hydrolysis and the amount of omega-3 fatty acid was also investigated. The variables used in this research were temperatures (25-65 oC, pH (5-9, and water addition (1-5 %v/v. The highest degree of enzymatic hydrolysis of fish oil in the media without hexane was 28.07 % that was reached at 45oC and pH 5. In the presence of hexane, the highest degree of hydrolysis was 75.12 % which was reached at 5% water addition, temperature 45oC, and pH 5. GC-MS analysis showed that omega-3 fatty acid content especially EPA and DHA increased along with increase in the degree of hydrolysis. Concentration of omega-3 fatty acid produced without hexane addition was 18.42 % with EPA amounted to 12,17% and DHA 0,86%. Meanwhile omega-3 fatty acid content in the presence of hexane reached 21.93 % with EPA amounted to 17.75 % and DHA 1.21 %.
Yadav, Kaushlesh K; Garg, Neelima; Kumar, Devendra; Kumar, Sanjay; Singh, Achal; Muthukumar, M
Polygalacturonase (PG) degrades pectin into D-galacturonic acid monomers and is used widely in food industry especially for juice clarification. In the present study,. fermentation conditions for polygalacturonase production by Asgergillus niger NAIMCCF-02958, using mango peel as substrate, were optimized using the 2(3) factorial design with central composite rotatable experimental design (CCRD) of response surface methodology (RSM). The maximum PG activity 723.66 U g(-1) was achieved under pH 4.0, temperature 30 degrees C and 2% inoculum by response surface curve. The experimental value of PG activity wkas higher 607.65 U g(-1) than the predicted value 511.75 U g(-1). Under the proposed optimized conditions, the determination coefficient (R2) was equal to 0.66 indicating that the model could explain 66% of the total variation as well as establish the relationship between the variables and the responses. ANOVA analysis and the three dimensional plots also confirmed interactions among the parameters.
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
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.
Sathishkumar, Yesupatham; Velmurugan, Natarajan; Lee, Hyun Mi; Rajagopal, Kalyanaraman; Im, Chan Ki; Lee, Yang Soo
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.
Jørgensen, Thomas R; vanKuyk, Patricia A; Poulsen, Bjarne R
This is a study of high-affinity glucose uptake in Aspergillus niger and the effect of disruption of a high-affinity monosaccharide-transporter gene, mstA. The substrate saturation constant (K(s)) of a reference strain was about 15 microM in glucose-limited chemostat culture. Disruption of mst......-affinity uptake system of A. niger. The mstA disruptant and a reference strain were cultivated in glucose-limited chemostat cultures at low, intermediate and high dilution rate (D=0.07 h(-1), 0.14 h(-1) and 0.20 h(-1)). Mycelium harvested from steady-state cultures was subjected to glucose uptake assays...
马存强; 李静; 周斌星; 柴洁; 杨超; 任小盈; 张梦华
The essence of pu-erh tea solid-fermentation process is microbial metabolism , and Aspergillus niger is a dominant fungus in the metabolism and has a huge impact on caffeine metabolism .In this study, Aspergillus niger strains were inoculated into tea, tea infusion, and liquid medium containing caffeine , then the content of purine base at different stages of fermentation was de -termined .The results showed that Aspergillus niger had grater effect on theophylline than on theobromine , and greater effect on theo-bromine than on caffeine .In addition , during the liquid -fermentation of pure caffeine , theophylline content increased to a maxi-mum extent , and it was positively correlated with caffeine concentration .%普洱茶固态发酵过程的实质是微生物代谢作用，而黑曲霉在代谢中为优势菌，对咖啡碱代谢产生巨大影响。以黑曲霉为单一菌种，分别接种到茶叶、茶汤和含咖啡碱的液态培养基，并测定不同发酵阶段嘌呤碱的含量。结果表明，黑曲霉对茶叶碱的影响大于可可碱，对可可碱的影响大于咖啡碱，在咖啡碱液态培养基发酵中，茶叶碱增加幅度最大，且与咖啡碱浓度存在正相关性。
Huang, Jian-Wen; Chen, Chun-Chi; Huang, Chun-Hsiang; Huang, Ting-Yung; Wu, Tzu-Hui; Cheng, Ya-Shan; Ko, Tzu-Ping; Lin, Cheng-Yen; Liu, Je-Ruei; Guo, Rey-Ting
β-Mannanase has found various biotechnological applications because it is capable of degrading mannans into smaller sugar components. A highly potent example is the thermophilic β-mannanase from Aspergillus niger BK01 (ManBK), which can be efficiently expressed in industrial yeast strains and is thus an attractive candidate for commercial utilizations. In order to understand the molecular mechanism, which helps in strategies to improve the enzyme's performance that would meet industrial demands, 3D-structural information is a great asset. Here, we present the 1.57Å crystal structure of ManBK. The protein adopts a typical (β/α)8 fold that resembles the other GH5 family members. Polysaccharides were subsequently modeled into the substrate binding groove to identify the residues and structural features that may be involved in the catalytic reaction. Based on the structure, rational design was conducted to engineer ManBK in an attempt to enhance its enzymatic activity. Among the 23 mutants that we constructed, the most promising Y216W showed an 18±2.7% increase in specific activity by comparison with the wild type enzyme. The optimal temperature and heat tolerance profiles of Y216W were similar to those of the wild type, manifesting a preserved thermostability. Kinetic studies showed that Y216W has higher kcat values than the wild type enzyme, suggesting a faster turnover rate of catalysis. In this study we applied rational design to ManBK by using its crystal structure as a basis and identified the Y216W mutant that shows great potentials in industrial applications.
Liu, Guang; Hu, Songqing; Li, Lin; Hou, Yi
An extracellular lipase (EC 22.214.171.124, AN0512Lip) from Aspergillus niger AN0512 was purified and its characteristics were investigated. After the process of ammonium sulfate precipitation followed by ion-exchange chromatography and gel filtration, the purified lipase was achieved with 203.6-fold purification and 22.1 % recovery. AN0512Lip exhibited the highest activity at 50 °C and pH 5.0. It was thermostable and pH-stable, as indicated by that more than 50 % activity retained at 60 °C for 20 h and more than 90 % activity retained at pH 3.0 for 20 h, respectively. AN0512Lip activity was stimulated by some divalent metal ions (especially Cu(2+), Ca(2+)), while greatly suppressed by EDTA, indicating that AN0512Lip was a metal-activated enzyme. Moreover, AN0512Lip exhibited high tolerance for various polar organic solvents with log P lipase activity (476 % of its original activity) was achieved after addition of 90 % (V/V) isopropanol to the reaction mixture. AN0512Lip also displayed 3-regiospecificity and great affinity for the long-chain fatty ester. The preliminary test showed that AN0512Lip was a candidate for enriching EPA and DHA in fish oil. All the unique properties, such as thermostability, Cu(2+)-dependent, 3-regiospecificity, and polar organic solvent-tolerance, indicated that AN0512Lip could have potential applications in the food industry, even in organic synthesis and the pharmaceutical industry.
Xu, Hanfu; Liu, Yaowen; Wang, Feng; Yuan, Lin; Wang, Yuancheng; Ma, Sanyuan; Beneš, Helen; Xia, QingYou
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.
Mostafa, Yasser S; Alamri, Saad A
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.
Khatri, Bhim Prakash; Bhattarai, Tribikram; Shrestha, Sangita; Maharjan, Jyoti
Pectinase enzymes are one of the commercially important enzymes having great potential in various industries especially in food industry. Pectinases accounts for 25 % of global food enzymes produced and their market is increasing day by day. Therefore, the exploration of microorganism with novel characteristics has always been the focus of the research. Microorganism dwelling in unique habitat may possess unique characteristics. As such, a pectinase producing fungus Aspergillus niger strain MCAS2 was isolated from soil of Manaslu Conservation Area (MCA), Gorkha, Nepal. The optimum production of pectinase enzyme was observed at 48 h of fermentation. The pectinase enzyme was partially purified by cold acetone treatment followed by Sephadex G-75 gel filtration chromatography. The partially purified enzyme exhibited maximum activity 60 U/mg which was almost 8.5-fold higher than the crude pectinase. The approximate molecular weight of the enzyme was found to be 66 kDa as observed from SDS-PAGE. The pectinase enzyme was active at broad range of temperature (30-70 °C) and pH (6.2-9.2). Optimum temperature and pH of the pectinase enzyme were 50 °C and 8.2 respectively. The enzyme was stable up to 70 °C and about 82 % of pectinase activity was still observed at 100 °C. The thermostable and alkaline nature of this pectinase can meet the demand of various industrial processes like paper and pulp industry, in textile industry, fruit juice industry, plant tissue maceration and wastewater treatment. In addition, the effect of different metal ions on pectinase activity was also studied.
Ilmi, Miftahul; Hidayat, C.; Hastuti, P .; Heeres, Hero; Maarel, Marc van der
Jatropha curcas L. is a tropical plant that grows well on poor soils in arid regions and produces oil-rich, unedible seeds. The oil from these seeds can be used in the production of biodiesel. In addition, the press-cake waste that is left after oil extraction contains approximately 40% of protein. The use of Jatropha press-cake as substrate for fungal growth and the production of lipase by Aspergillus niger 65I6 isolated from Indonesia and Rhizomucor miehei CBS 260.62 was investigated. Hydro...
Rigoberto Ramos; Arturo Cano-Flores
La esclareólida (1) se biotransformó con Aspergillus niger (ATCC 20107) en tres medios de cultivos diferentes, obteniéndose cuatro productos de oxidación en los C-1 y C-3 de la esclareólida (1): 3-cetoesclareólida (2), 1 -hidroxiesclareólida (3), 3 B-hidroxiesclareólida (4) y 1-cetoesclareólida (17). El rendimiento y diversidad de los productos obtenidos, al parecer están determinados por la composición química del medio de cultivo.
毕瑞明; 孙迅; 任少亭
正交设计试验结果表明,黑曲霉(Aspergillus niger m12)产木聚糖酶活力达76.60 u/ml,合适的产酶发酵条件如下,培养基(g/L):麸皮40,尿素6.67,KH2PO41.0,MgSO4·7H2O 0.5,NaCl 0.3,Tween-80 3.0,CaCO3 2.0,28℃,120 r/min水浴振荡培养5.5 d.
陈国参; 周伏忠; 刘德海; 张秀江; 宁萌
从实验室保藏的菌株中,通过诱变选育出一株酸生蛋白酶高产菌株黑曲霉(A spergillus niger) UV11,对菌株发酵产酶的培养基组成及培养条件等工艺参数进行了优化研究.结果表明,菌株UV11在m(麸皮)∶m(花生壳粉)=6∶4,豆粕质量分数10％,(NH4) 2SO42％,MgSO4·7H2O 0.05％,K2HPO40.1％的培养基质上,控制m(料)∶m(水)=1∶11,接种量105～106个/g,28～30℃下培养24～30 h时,菌株UV11的产酶量∶酸性蛋白酶1190 U/g,纤维素酶8024U/g,木聚糖酶5192U/g,糖化酶1080 U/g.对菌株中试生产时的产酶规律和酶的热稳定性进行了研究,发现菌株UV11所产的复合酶具有良好的热稳定性,可用于饲料工业中颗粒料的加工生产.%Through the mutagenesis of Aspergillus niger conidia and its protoplasts with the ultraviolet, we obtained an excellent strain A.niger UV11 capable of producing high-yield acid proteases,xylases and cellulases etc. After several significant factors and media optimalizating studies, we concluded that: the media of wheatbran/shell powder of peanut 64, soybean-meal 10%, (NH4)SO4 2%, MgSO4·7H2O 0.05%,K2HPO4 0.1%, the ratio of materials and water 1:1.1 were suited for UV11 strain to producing complex enzymes. And with a conditions of inoculum 105~106/g, culture temperature of 28~30℃ for 24-30 h,the complex enzymes productions are as fouows:acid proteases 1190 U/g,xylases 5192 U/g, cellulases 8024 U/g and the glucoamylase 1080 U/g. Furthermore, the complex heat-stationary property were tested and the result showed that after 85 ℃,60 min treatment,the survival enzyme activity of the complex were more than 90%.
Huitrón, Carlos; Pérez, Rosalba; Gutiérrez, Luís; Lappe, Patricia; Petrosyan, Pavel; Villegas, Jesús; Aguilar, Cecilia; Rocha-Zavaleta, Leticia; Blancas, Abel
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, Bagsværd, 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.
Susca, Antonia; Proctor, Robert H.; Morelli, Massimiliano; Haidukowski, Miriam; Gallo, Antonia; Logrieco, Antonio F.; Moretti, Antonio
The fungi Aspergillus niger and A. welwitschiae are morphologically indistinguishable species used for industrial fermentation and for food and beverage production. The fungi also occur widely on food crops. Concerns about their safety have arisen with the discovery that some isolates of both species produce fumonisin (FB) and ochratoxin A (OTA) mycotoxins. Here, we examined FB and OTA production as well as the presence of genes responsible for synthesis of the mycotoxins in a collection of 92 A. niger/A. welwitschiae isolates from multiple crop and geographic origins. The results indicate that (i) isolates of both species differed in ability to produce the mycotoxins; (ii) FB-nonproducing isolates of A. niger had an intact fumonisin biosynthetic gene (fum) cluster; (iii) FB-nonproducing isolates of A. welwitschiae exhibited multiple patterns of fum gene deletion; and (iv) OTA-nonproducing isolates of both species lacked the ochratoxin A biosynthetic gene (ota) cluster. Analysis of genome sequence data revealed a single pattern of ota gene deletion in the two species. Phylogenetic analysis suggest that the simplest explanation for this is that ota cluster deletion occurred in a common ancestor of A. niger and A. welwitschiae, and subsequently both the intact and deleted cluster were retained as alternate alleles during divergence of the ancestor into descendent species. Finally, comparison of results from this and previous studies indicate that a majority of A. niger isolates and a minority of A. welwitschiae isolates can produce FBs, whereas, a minority of isolates of both species produce OTA. The comparison also suggested that the relative abundance of each species and frequency of FB/OTA-producing isolates can vary with crop and/or geographic origin. PMID:27667988
de Alencar Guimaraes, Nelciele ; Sorgatto, Michele ; Nogueira, Simone de Peixoto; Betini, Jorge Henrique ; Zanoelo, Fabiana ; Marques, Maria ; Polizeli, Maria de Lourdes Teixeira de Moraes; Giannesi, Giovana C
This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50°C, the xylanase of A. niger retained over 85% activity with 2 h of ...
Full Text Available 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."nMaterials 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."nResults: 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."nConclusion: 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.
Chotpatiwetchkul, Warot; Jongkon, Nathjanan; Hannongbua, Supa; Gleeson, M Paul
Aspergillus niger is an industrially important microorganism used in the production of citric acid. It is a common cause of food spoilage and represents a health issue for patients with compromised immune systems. Recent studies on Aspergillus niger have revealed details on the isocitrate lyase (ICL) superfamily and its role in catabolism, including (2R, 3S)-dimethylmalate lyase (DMML). Members of this and related lyase super families are of considerable interest as potential treatments for bacterial and fungal infections, including Tuberculosis. In our efforts to better understand this class of protein, we investigate the catalytic mechanism of DMML, studying five different substrates and two different active site metals configurations using molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. We show that the predicted barriers to reaction for the substrates show good agreement with the experimental kcat values. This results help to confirm the validity of the proposed mechanism and open up the possibility of developing novel mechanism based inhibitors specifically for this target.
Segers, Frank J. J.; van Laarhoven, Karel A.; Huinink, Hendrik P.; Adan, Olaf C. G.; Wösten, Han A. B.
ABSTRACT Indoor fungi cause damage in houses and are a potential threat to human health. Indoor fungal growth requires water, for which the terms water activity (aw) and relative humidity (RH) are used. The ability of the fungi Aspergillus niger, Cladosporium halotolerans, and Penicillium rubens at different developmental stages to survive changes in aw dynamics was studied. Fungi grown on media with high aw were transferred to a controlled environment with low RH and incubated for 1 week. Growth of all developmental stages was halted during incubation at RHs below 75%, while growth continued at 84% RH. Swollen conidia, germlings, and microcolonies of A. niger and P. rubens could not reinitiate growth when retransferred from an RH below 75% to a medium with high aw. All developmental stages of C. halotolerans showed growth after retransfer from 75% RH. Dormant conidia survived retransfer to medium with high aw in all cases. In addition, retransfer from 84% RH to medium with high aw resulted in burst hyphal tips for Aspergillus and Penicillium. Cell damage of hyphae of these fungi after incubation at 75% RH was already visible after 2 h, as observed by staining with the fluorescent dye TOTO-1. Thus, C. halotolerans is more resistant to aw dynamics than A. niger and P. rubens, despite its limited growth compared to that of these fungi at a lowered steady-state aw. The survival strategy of this phylloplane fungus in response to the dynamics of aw is discussed in relation to its morphology as studied by cryo-scanning electron microscopy (cryo-SEM). IMPORTANCE Indoor fungi cause structural and cosmetic damage in houses and are a potential threat to human health. Growth depends on water, which is available only at certain periods of the day (e.g., during cooking or showering). Knowing why fungi can or cannot survive indoors is important for finding novel ways of prevention. Until now, the ability of fungi to grow on media with little available water at steady state
Flávera Camargo Prado
Full Text Available The aim of this work was to study the relation between citric acid production and respiration of Aspergillus niger LPB 21 in solid-state fermentation of cassava bagasse. The experiments were carried out in horizontal drum bioreactor coupled with a gas chromatography system. Fermentation was conduced for 144 h with initial substrate moisture of 60% using heat-treated cassava bagasse as sole carbon source. The exhausted air from the bioreactor was analyzed for the monitoring of CO2 produced and O2 consumed in order to estimate the biomass biosynthesis by the fungal culture. The metabolic activity of A. niger growth was associated to citric acid production. The system using FERSOL software determined 4.372 g of biomass/g of consumed O2. Estimated and analytically determined biomass values followed the same pattern showing that the applied mathematical model was adapted.Este estudo permitiu verificar a relação ente a produção de ácido cítrico e a respiração do Aspergillus niger LPB 21 na fermentação no estado sólido do bagaço de mandioca. Os experimentos foram realizados em biorreator tipo tambor horizontal acoplado com um sistema de cromatografia gasosa. A fermentação foi conduzida durante 144 h com 60% de umidade inicial do substrato usando bagaço de mandioca termicamente tratado como única fonte de carbono. O ar de saída do biorreator foi analisado para monitorar a produção de CO2 e o consumo de O2 com o objetivo de estimar a biomassa sintetizada pelo fungo. A atividade metabólica do crescimento do Aspergillus niger está associada à produção de ácido cítrico. Usando o software FERSOL, o sistema determinou uma biomassa de 4.372 g de biomassa/g de O2 consumido. Os valores da biomassa estimada e da determinada analiticamente seguiram a mesma tendência mostrando que o modelo matemático aplicado foi adaptado.
Levasseur, A.; Pagès, S.; Fierobe, H.-P.; Navarro, D.; Punt, P.; Belaïch, J.-P.; Asther, M.; Record, E.
A chimeric enzyme associating feruloyl esterase A (FAEA) from Aspergilhis niger and dockerin from Clostridium thermocellum was produced in A. niger. A completely truncated form was produced when the dockerin domain was located downstream of the FAEA (FAEA-Doc), whereas no chimeric protein was produc
Liu, Jing; Zhou, Lin; Chen, Ji-Hong; Mao, Wang; Li, Wen-Jian; Hu, Wei; Wang, Shu-Yang; Wang, Chun-Ming
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.
Kirimura, Kohtaro; Kobayashi, Keiichi; Ueda, Yuka; Hattori, Takasumi
The mitochondrial citrate transport protein (CTP) functions as a malate-citrate shuttle catalyzing the exchange of citrate plus a proton for malate between mitochondria and cytosol across the inner mitochondrial membrane in higher eukaryotic organisms. In this study, for functional analysis, we cloned the gene encoding putative CTP (ctpA) of citric acid-producing Aspergillus niger WU-2223L. The gene ctpA encodes a polypeptide consisting 296 amino acids conserved active residues required for citrate transport function. Only in early-log phase, the ctpA disruptant DCTPA-1 showed growth delay, and the amount of citric acid produced by strain DCTPA-1 was smaller than that by parental strain WU-2223L. These results indicate that the CTPA affects growth and thereby citric acid metabolism of A. niger changes, especially in early-log phase, but not citric acid-producing period. This is the first report showing that disruption of ctpA causes changes of phenotypes in relation to citric acid production in A. niger.
Kobayashi, Keiichi; Hattori, Takasumi; Hayashi, Rie; Kirimura, Kohtaro
In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering.
Kyung Hoon Chang
Full Text Available The transformation of ginsenoside Rb1 into a specific minor ginsenoside using Aspergillus niger KCCM 11239, as well as the identification of the transformed products and the pathway via thin layer chromatography and high performance liquid chromatography were evaluated to develop a new biologically active material. The conversion of ginsenoside Rb1 generated Rd, Rg3, Rh2, and compound K although the reaction rates were low due to the low concentration. In enzymatic conversion, all of the ginsenoside Rb1 was converted to ginsenoside Rd and ginsenoside Rg3 after 24 h of incubation. The crude enzyme (β-glucosidase from A. niger KCCM 11239 hydrolyzed the β-(1→6-glucosidic linkage at the C-20 of ginsenoside Rb1 to generate ginsenoside Rd and ginsenoside Rg3. Our experimental demonstration showing that A. niger KCCM 11239 produces the ginsenoside-hydrolyzing β-glucosidase reflects the feasibility of developing a specific bioconversion process to obtain active minor ginsenosides.
Dai, Ziyu; Aryal, Uma K.; Shukla, Anil; Qian, Wei-Jun; Smith, Richard D.; Magnuson, Jon K.; Adney, William S.; Beckham, Gregg T.; Brunecky, Roman; Himmel, Michael E.; Decker, Stephen R.; Ju, Xiaohui; Zhang, Xiao; Baker, Scott E.
ALG3 is a Family 58 glycosyltransferase enzyme involved in early N-linked glycan synthesis. Here, we investigated the effect of the alg3 gene disruption on growth, development, metabolism, and protein secretion in Aspergillus niger. The alg3 gene deletion resulted in a significant reduction of growth on complete (CM) and potato dextrose agar (PDA) media and a substantial reduction of spore production on CM. It also delayed spore germination in the liquid cultures of both CM and PDA media, but led to a significant accumulation of red pigment on both CM and liquid modified minimal medium (MM) supplemented with yeast extract. The relative abundance of 55 proteins of the total 190 proteins identified in the secretome was significantly different as a result of alg3 gene deletion. Comparison of a Trichoderma reesei cellobiohydrolase (Cel7A) heterologously expressed in A. niger parental and Δalg3 strains showed that the recombinant Cel7A expressed in the mutant background was smaller in size than that from the parental strains. This study suggests that ALG3 is critical for growth and development, pigment production, and protein secretion in A. niger. Functional analysis of recombinant Cel7A with aberrant glycosylation demonstrates the feasibility of this alternative approach to evaluate the role of N-linked glycosylation in glycoprotein secretion and function.
Hattingh, M; Alexander, A; Meijering, I; van Reenen, C A; Dicks, L M T
Good quality malt is characterised by the presence of high levels of fermentable sugars, amino acids and vitamins. To reach the starch-rich endosperm of the kernel, β-glucan- and arabinoxylan-rich cell walls have to be degraded. β-Glucanase is synthesized in vast quantities by the aleurone layer and scutellum during germination. Secretion of hydrolytic enzymes is often stimulated by addition of the plant hormone gibberellic acid (GA3) during germination. We have shown an enhanced β-glucanase and α-amylase activity in malt when germinating barley was inoculated with a combination of Lactobacillus plantarum B.S1.6 and spores of Aspergillus niger MH1, Rhizopus oligosporus MH2 or Trichoderma reesei MH3, and L. plantarum B.S1.6 combined with cell-free culture supernatants from each of these fungi. Highest malt β-glucanase activity (414 Units/kg malt) was recorded with a combination of L. plantarum B.S1.6 and spores of A. niger MH1. Highest α-amylase activities were recorded with a combination of L. plantarum B.S1.6 and spores of R. oligosporus MH2 (373 Ceralpha Units/g malt). Highest FAN levels were recorded when L. plantarum was inoculated in combination with spores of either R. oligosporus MH2 or T. reesei MH3 (259 and 260 ppm, respectively). This is the first study showing that cell-free culture supernatants of Aspergillus, Rhizopus and Trichoderma have a stimulating effect on β-glucanase and α-amylase production during malting. A combination of L. plantarum B.S1.6, and spores of A. niger MH1 and R. oligosporus MH2 may be used as starter cultures to enhance malt quality.
Atkin, Kate E; Reiss, Renate; Koehler, Valentin; Bailey, Kevin R; Hart, Sam; Turkenburg, Johan P; Turner, Nicholas J; Brzozowski, A Marek; Grogan, Gideon
Monoamine oxidase from Aspergillus niger (MAO-N) is a flavoenzyme that catalyses the oxidative deamination of primary amines. MAO-N has been used as the starting model for a series of directed evolution experiments, resulting in mutants of improved activity and broader substrate specificity, suitable for application in the preparative deracemisation of primary, secondary and tertiary amines when used as part of a chemoenzymatic oxidation-reduction cycle. The structures of a three-point mutant (Asn336Ser/Met348Lys/Ile246Met or MAO-N-D3) and a five-point mutant (Asn336Ser/Met348Lys/Ile246Met/Thr384Asn/Asp385Ser or MAO-N-D5) have been obtained using a multiple-wavelength anomalous diffraction experiment on a selenomethionine derivative of the truncated MAO-N-D5 enzyme. MAO-N exists as a homotetramer with a large channel at its centre and shares some structural features with human MAO B (MAO-B). A hydrophobic cavity extends from the protein surface to the active site, where a non-covalently bound flavin adenine dinucleotide (FAD) sits at the base of an 'aromatic cage,' the sides of which are formed by Trp430 and Phe466. A molecule of l-proline was observed near the FAD, and this ligand superimposed well with isatin, a reversible inhibitor of MAO-B, when the structures of MAO-N proline and MAO-B-isatin were overlaid. Of the mutations that confer the ability to catalyse the oxidation of secondary amines in MAO-N-D3, Asn336Ser reduces steric bulk behind Trp430 of the aromatic cage and Ile246Met confers greater flexibility within the substrate binding site. The two additional mutations, Thr384Asn and Asp385Ser, that occur in the MAO-N-D5 variant, which is able to oxidise tertiary amines, appear to influence the active-site environment remotely through changes in tertiary structure that perturb the side chain of Phe382, again altering the steric and electronic character of the active site near FAD. The possible implications of the change in steric and electronic environment
Sánchez-Torres, Paloma; Visser, Jaap; Benen, Jacques A E
Site-directed-mutagenesis studies were performed on family 1 pectin lyase A (PL1A) from Aspergillus niger to gain insight into the reaction mechanism for the pectin lyase-catalysed beta-elimination cleavage of methylesterified polygalacturonic acid and to stabilize the enzyme at slightly basic pH. On the basis of the three-dimensional structures of PL1A [Mayans, Scott, Connerton, Gravesen, Benen, Visser, Pickersgill and Jenkins (1997) Structure 5, 677-689] and the modelled enzyme-substrate complex of PL1B [Herron, Benen, Scavetta, Visser and Jurnak (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 8762-8769], Asp154, Arg176, Arg236 and Lys239 were mutagenized. Substituting Arg236 with alanine or lysine rendered the enzyme completely inactive, and mutagenesis of Arg176 and Lys239 severely affected catalysis. The Asp154-->Arg and Asp154-->Glu mutant enzymes were only moderately impaired in respect of catalysis. The results strongly indicate that Arg236, which is sandwiched between Arg176 and Lys239, would initiate the reaction upon enzyme-substrate interaction, through the abstraction of the proton at C5 of the galacturonopyranose ring. The positively charged residues Arg176 and Lys239 are responsible for lowering the p K a of Arg236. Arg176 and Lys239 are maintained in a charged state by interacting with Asp154 or bulk solvent respectively. The deprotonation of the Asp186-Asp221 pair was proposed to be responsible for a pH-driven conformational change of PL1A [Mayans, Scott, Connerton, Gravesen, Benen, Visser, Pickersgill and Jenkins (1997) Structure 5, 677-689]. Substitution of Asp186 and Asp221 by Asn186 and Asn221 was expected to stabilize the enzyme. However, the Asp186-->Asn/Asp221-->Asn enzyme appeared less stable than the wild-type enzyme, even at pH 6.0, as evidenced by fluorescence studies. This demonstrates that the pH-dependent conformational change is not driven by deprotonation of the Asp186-Asp221 pair.
von Sperber, C.; Tamburini, F.; Brunner, B.; Bernasconi, S. M.; Frossard, E.
Phosphorus (P) is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi) from organic phosphorus compounds (Porg). Phytic acid (myo-inositol hexakisphosphate, IP6) is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields available Pi and less phosphorylated inositol derivates as products. The hydrolysis of organic P compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O) of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'-monophosphate (AMP) and glycerophosphate (GPO4) as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as a substrate were prepared. During the hydrolysis of IP6 by phytase, four of the six Pi were released, and one oxygen atom from water was incorporated into each Pi. This incorporation of oxygen from water into Pi was subject to an apparent inverse isotopic fractionation (ϵ ~ 6 to 10 ‰), which was similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ~ 7 ‰), where less than three Pi were released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ~ -12 ‰), similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ϵ to the same amino acid sequence motif (RHGXRXP) at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking
C. v. Sperber
Full Text Available Phosphorus (P is an essential nutrient for living organisms. Under P-limiting conditions plants and microorganisms can exude extracellular phosphatases that release inorganic phosphate (Pi from organic phosphorus compounds (Porg. Phytic acid (IP6 is an important form of Porg in many soils. The enzymatic hydrolysis of IP6 by phytase yields plant available inorganic phosphate (Pi and less phosphorylated inositol derivates as products. The hydrolysis of organic P-compounds by phosphatases leaves an isotopic imprint on the oxygen isotope composition (δ18O of released Pi, which might be used to trace P in the environment. This study aims at determining the effect of phytase on the oxygen isotope composition of released Pi. For this purpose, enzymatic assays with histidine acid phytases from wheat and Aspergillus niger were prepared using IP6, adenosine 5'monophosphate (AMP and glycerophosphate (GPO4 as substrates. For a comparison to the δ18O of Pi released by other extracellular enzymes, enzymatic assays with acid phosphatases from potato and wheat germ with IP6 as substrate were prepared. During the hydrolysis of IP6 by phytase, four Pi are released, and one oxygen atom from water is incorporated into each Pi. This incorporation of oxygen from water into Pi is subject to an apparent inverse isotopic fractionation (ϵ ∼ 6 to 10‰, which is similar to that imparted by acid phosphatase from potato during the hydrolysis of IP6 (ϵ ∼ 7‰ where less than three Pi are released. The incorporation of oxygen from water into Pi during the hydrolysis of AMP and GPO4 by phytase yielded a normal isotopic fractionation (ϵ ∼ −12‰, again similar to values reported for acid phosphatases from potato and wheat germ. We attribute this similarity in ε to the same amino acid sequence motif (RHGXRXP at the active site of these enzymes, which leads to similar reaction mechanisms. We suggest that the striking substrate
de Alencar Guimaraes, Nelciele Cavalieri; Sorgatto, Michele; Peixoto-Nogueira, Simone de Carvalho; Betini, Jorge Henrique Almeida; Zanoelo, Fabiana Fonseca; Marques, Maria Rita; de Moraes Polizeli, Maria de Lourdes Teixeira; Giannesi, Giovana C
This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50°C, the xylanase of A. niger retained over 85% activity with 2 h of incubation, and A. flavus had a half-life of more than 75 minutes. At 55°C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45 minutes. The xylanase activity of A. niger and A. flavus were somehow protected in the presence of glycerol 5% when compared to the control (without additives). On the biobleaching assay it was observed that the xylanase from A. flavus was more effective in comparison to A. niger. The kappa efficiency corresponded to 36.32 and 25.93, respectively. That is important to emphasize that the cellulase activity was either analyzed and significant levels were not detected, which explain why the viscosity was not significantly modified.
Franken, A.C.; Christien Lokman, B.; Ram, A.F.; Hondel, C.A. van den; Weert, S. de; Punt, P.J.
To increase knowledge on haem biosynthesis in filamentous fungi like Aspergillus niger, pathway-specific gene expression in response to haem and haem intermediates was analysed. This analysis showed that iron, 5′-aminolevulinic acid (ALA) and possibly haem control haem biosynthesis mostly via modula
Saifeldin A. F. El-Nagerabi
Full Text Available Black mold disease caused by Aspergillus niger V. Tiegh. is the most devastating infection occurs in onions Allium cepa L. under field and store conditions. The use of biocontrol agents is ecofriendly approach for controlling seedborne and soilborne diseases compared to the use of toxic synthetic fungicides. This study has been designed to assess the contamination levels of onion seeds with A. niger and its effect on seed germination and to evaluate the in vitro antifungal activity of Prunus mahaleb seeds Commiphora myrrha resin 0.5 1.0 1.5 2.0 g100 ml Syzygium aromaticum dry buds clove and Panax ginseng roots extracts 0.5 1.0 2.0 2.5 g100 ml against black mold of onion bulbs. The fungus is seedborne pathogen which significantly contaminated onion seeds 89-100 and reduced seed germination 39-83. The extracts of clove caused 43-96 inhibition in spore germination followed by mahaleb 37-96 myrrha 33-88 and ginseng 34-87. The highest concentration of these extracts 3.0 did not affect seed germination but significantly reduced seed contamination by A. niger up to 84 80 71 and 65 for Syzygium aromaticum Syzygium aromaticum Panax ginseng and Prunus mahaleb respectively. The extracts apparently inhibited the fungal growth and mold development on stored onion bulbs which indicates the antifungal property of these extracts against A. niger. Therefore they can be recommended as effective biocontrol agents to reduce seed contamination and enhance the storability of onion bulbs. Thus the use of healthy and certified seeds for onion production is a priority.
[Objective]The aim was to research the relationships between the side chain of maleic anhydride structure compounds and inhibition effect on Aspergillus niger. [Method]Choosing 7 kinds of common compounds with maleic anhydride structure and tautomycin, the test of inhibiting Aspergillus niger was carried out by using oxford cup method. [Result]Diphenylmaleic anhydride with the concentration of 10 g/L had a good inhibition on Aspergillus niger, while tautomycin with the lower concentration of 1 g/L also had a considerable inhibition effect. [Conclusions]The side chain of maleic anhydride structure compounds containing chlorine could promote the inhibition effect on Aspergillus niger, and containing benzene couldn't enhance the activity of inhibition on Aspergillus niger.%[目的]研究含顺丁烯二酸酐结构化合物侧链结构与抑制黑曲霉效果的关系. [方法]选取7种常见含顺丁烯二酸酐结构化合物以及变构霉素,用牛津杯法进行抑制黑曲霉试验.[结果]3, 6-二氯邻苯二甲酸酐在10 g/L浓度下对黑曲霉有较好的抑制作用,变构霉素在1 g/L 浓度下仍对黑曲霉有一定的抑制作用. [结论]含顺丁烯二酸酐结构化合物侧链含有氯对抑制黑曲霉有促进作用,而含有苯环则不能增强其对抑制黑曲霉的活性.
蒋树海; 孙君社; 卢华; 周庆礼
通过单次单因素试验对黑曲霉(Aspergillus nigerS-05)液体发酵的产柚苷酶条件进行优化,结果表明,当培养条件为豆粉2.0%、蔗糖0.5%、柚苷0.05%、MgSO4·7H2O 0.6%、吐温-80 0.2%、培养温度26℃、初始pH 5.0、250 mL三角瓶装量30mL、转速190r/min、培养时间105 h时柚苷酶酶活达到最高值(429.09U/mL).同时发现,通过调节培养基组成可改变所产柚苷酶中α-L-鼠李糖苷酶和β-D-葡萄糖苷酶的酶活比例,从而实现根据不同应用进行有针对性的发酵产酶控制目的.
李冰; 董征英; 常维山
试验利用黑曲霉对黄曲霉毒素B1进行了降解率、活性组分的确定、安全性及对饲料中降解黄曲霉毒素效果的研究。研究结果表明,黑曲霉对黄曲霉毒素B1的降解率达93.28%,其中黑曲霉的胞外粗提液对黄曲霉毒素B1的降解活性最高,证明黑曲霉对黄曲霉毒素B1的降解是一种生物化学反应,黑曲霉发酵液对饲料中的黄曲霉毒素B1具有很强的降解作用。小鼠的急性毒理学试验证明,试验用黑曲霉本身具有良好的安全性。%The determination of degradation efficiency and active components of aflatoxin B1 safety and the effect of degradation aflatoxin in feed about the screened aspergillus was researched in this experiment used aspergillus niger. The result showed that the degradation of aflatoxin B1 by aspergillus niger was 93.28%, the degrading efficiencies of aflatoxin B1 by exocellular coarse extraction liquid was highest, and this proved that the degration of aflatoxin B1 by aspergillus niger was a biological reaction. The degrading effect of aflatoxin B1 in feed by aspergillus fermented liquid was strong. A favorable safety of aspergillus niger was testified through the acute toxicology experiments in mice.
Production and characterization of glucoamylase from fungus Aspergillus awamori expressed in yeast Saccharomyces cerevisiae using different carbon sources Produção e caracterização da glucoamilase do fungo Aspergillus awamori expressa em levedura Saccharomyces cerevisiae usando diferentes fontes de carbono
Fabiana Carina Pavezzi
Full Text Available Glucoamylase is widely used in the food industry to produce high glucose syrup, and also in fermentation processes for production beer and ethanol. In this work the productivity of the glucoamylase of Aspergillus awamori expressed by the yeast Saccharomyces cerevisiae, produced in submerged fermentation using different starches, was evaluated and characterized physico-chemically. The enzyme presented high specific activity, 13.8 U/mgprotein or 2.9 U/mgbiomass, after 48 h of fermentation using soluble starch as substrate. Glucoamylase presented optimum activity at temperature of 55ºC, and, in the substratum absence, the thermostability was for 1h at 50ºC. The optimum pH of activity was pH 3.5 - 4.0 and the pH stability between 5.0 and 7.0. The half life at 65ºC was at 30.2 min, and the thermal energy of denaturation was 234.3 KJ mol-1. The hydrolysis of different substrate showed the enzyme's preference for the substrate with a larger polymerization degree. The gelatinized corn starch was the substratum most susceptible to the enzymatic action.A glucoamilase é amplamente utilizada na indústria de alimentos no processamento do amido para a produção de xarope com alto teor de glicose e também muito empregada nos processos de fermentação para produção de cerveja e etanol. Neste trabalho a glucoamilase de Aspergillus awamori expressa em Saccharomyces cerevisiae produzida sob fermentação líquida foi avaliada quanto à produtividade em diferentes amidos e caracterizada físico-quimicamente. A enzima apresentou alta atividade específica de 13,8 U/mg proteína e de 2,9 U/mg biomassa ao final de 48 h de fermentação em meio contendo amido solúvel. A glucoamilase apresentou temperatura ótima de atividade a 55ºC, e temperatura de desnaturação térmica na ausência de substrato por 1h a 50ºC. O pH ótimo de atividade foi na faixa de 3,5 - 4,0 e a estabilidade ao pH entre os valores 5,0 e 7,0. A meia vida a 65ºC foi 30,2 min., e a
Wijk, van D.
Aspergillusis a filamentous fungus that can grow in many environments, on several substrates at different conditions. In the soil,Aspergillirecycle nutrients by the degradation of plant material. In particular,Aspergilliare known for their capabili
Darah; Ibrahim; Haritharan; Weloosamy; Sheh-Hong; Lim
AIM: To investigate the impact of agitation speed on pectinase production and morphological changing of Aspergillus niger(A. niger) HFD5A-1 in submerged fermentation. METHODS: A. niger HFM5A-1 was isolated from a rotted pomelo. The inoculum preparation was performed by adding 5.0 m L of sterile distilled water containing 0.1% Tween 80 to a sporulated culture. Cultivation was carried out with inoculated 1 × 107 spores/m L suspension and incubated at 30 ℃ with different agitation speed for 6 d. The samples were withdrawn after 6 d cultivation time and were assayed for pectinase activity and fungal growth determination. The culture broth was filtered through filter paper(Whatman No. 1, London) to separate the fungal mycelium. The cell-free culture filtrate containing the crude enzyme was then assayed for pectinase activity. The biomass was dried at 80 ℃ until constant weight. The fungal cell dry weight was then expressed as g/L. The 6 d old fungal mycelia were harvested from various agitation speed, 0, 50, 100, 150, 200 and 250 rpm. The morphological changing of samples was then viewed under the light microscope and scanning electron microscope.RESULTS: In the present study, agitation speed was found to influence pectinase production in a batch cultivation system. However, higher agitation speeds than the optimal speed(150 rpm) reduced pectinase production which due to shear forces and also collision among the suspended fungal cells in the cultivation medium. Enzyme activity increased with the increasing of agitation speed up to 150 rpm, where it achieved its maximal pectinase activity of 1.559 U/m L. There were significant different(Duncan, P < 0.05) of the pectinase production with the agitation speed at static, 50, 100, 200 and 250 rpm. At the static condition, a well growth mycelial mat was observed on the surface of the cultivation medium and sporulation occurred all over the fungal mycelial mat. However with the increased in agitation speed, the mycelial
Full Text Available Waste of sago processing, notably hampas (ela still contains sago starch is waste that has not been utilized optimally yet and causing pollution. Isolation and identification of glucoamylase producer fungus of sago hampas waste were aims to obtain isolates that have gluco-amylolytic properties, and to know glucoamylase activity of selected fungus isolates after grown on artificial medium. Indegeneous isolates that can produced glucoamylase will be use to get sugar hidrolysate from starch of sago hampas waste for bioetanol production. The study was conducted with the following stages: 1Take the sample from the tennis, 2 Isolation and Identification, 3 Characterization (clear zone, and 4 The production of glucoamylase from selected isolates, The results obtained are: 1 Isolation of fungi gluco-amylolytic from 2 sources sago hampas were produced 10 isolates. Ten isolates were divided into 4 genuses: Gliocladium (as dominant isolate, Aspergilus, Rizhopus and Geotrichum. Isolates of Gliocladium KE gaves the largest degradation of starch on PDA-Starch medium (clear zone, and followed by isolates of Aspergillus GA; 2 Production of glucoamylase on sago hampas with modificated Danial medium (1992 gave the highest activity of Gliocladium KE on the fifth day of incubation, namely: 10.72 U / mL of crude enzyme from the supernatant of fermentation substrate (S, and 17.16 U / mL for crude enzyme from the extract of isopropanol isolation (E.
Sharma, Amit; Vivekanand, V; Singh, Rajesh P
Solid-state fermentation (SSF) was evaluated to produce gluconic acid by metal resistant Aspergillus niger (ARNU-4) strain using tea waste as solid support and with molasses based fermentation medium. Various crucial parameters such as moisture content, temperature, aeration and inoculum size were derived; 70% moisture level, 30 degrees C temperature, 3% inoculum size and an aeration volume of 2.5l min(-1) was suited for maximal (76.3 gl(-1)) gluconic acid production. Non-clarified molasses based fermentation media was utilized by strain ARNU-4 and maximum gluconic acid production was observed following 8-12 days of fermentation cycle. Different concentrations of additives viz. oil cake, soya oil, jaggary, yeast extract, cheese whey and mustard oil were supplemented for further enhancement of the production ability of microorganism. Addition of yeast extract (0.5%) was observed inducive for enhanced (82.2 gl(-1)) gluconic acid production.
CARLOS ANDRÉS LÓPEZ RÍOS; ALEJANDRO ZULUAGA MENESES; SARA NATALIA HERRERA PENAGOS; ANGELA ADRIANA RUIZ COLORADO; VICTORIA ISABEL MEDINA DE PÉREZ
Con el fin de aprovechar el subproducto de la fabricación de queso blanco, se evaluó el suero de leche como sustrato para la producción de ácido cítrico utilizando Aspergillus niger NRRL 2270. Para este sustrato se comparó la hidrólisis ácida y enzimática de la lactosa con el fin de proporcionar al microorganismo una fuente de carbono más asimilable. En el suero entero (SE) y desproteinizado e hidrolizado (SDH), se estudió el efecto del pH y la adición de nitrógeno, además en el ...
López Ríos, Carlos Andrés; Zuluaga Meneses, Alejandro; Herrera Penagos, Sara Natalia; Ruiz Colorado, Angela Adriana
Con el fin de aprovechar el subproducto de la fabricación de queso blanco, se evaluó el suero de leche como sustrato para la producción de ácido cítrico utilizando Aspergillus niger NRRL 2270. Para este sustrato se comparó la hidrólisis ácida y enzimática de la lactosa con el fin de proporcionar al microorganismo una fuente de carbono más asimilable. En el suero entero (SE) y desproteinizado e hidrolizado (SDH), se estudió el efecto del pH y la adición de nitrógeno, además en el suero hidroli...