Showing papers on "Aspergillus niger published in 1982"
TL;DR: The elution profiles were consistent with GI and GII having similar polypeptide chains, however, digestion with carboxypeptidase Y showed different C-terminal residues of the two forms, suggesting great homology in the primary structure of theTwo forms.
Abstract: Aspergillus niger glucoamylases GI and GII (EC 3213) were isolated from a commercial enzyme preparation by ammonium sulfate precipitation followed by DEAE-cellulose ion exchange chromatography Both enzymes consist of a single glycosylated polypeptide chain The molecular weights of GI and GII were determined by sedimentation equilibrium ultracentrifugation to 52,000 and 46,000, respectively, and by molecular sieving to 65,000 and 55,000 The amino acid compositions of GI and GII were very similar Furthermore, the N-terminal amino acid sequence of the intact GI and GII as well as of their cyanogen fragments were identical, suggesting great homology in the primary structure of the two forms In addition the digests of GI and GII produced respectively by Armillaria mellea protease, Staphylococcus aureus V8 protease, and submaxillary protease were analyzed by high pressure gel permeation chromatography The elution profiles were also consistent with GI and GII having similar polypeptide chains However, digestion with carboxypeptidase Y showed different C-terminal residues of the two forms
147 citations
TL;DR: Catalase from Aspergillus niger was purified to homogeneity as judged from the results of ultracentrifugation and polyacrylamide gel electrophoresis, suggesting that the native enzyme consists of four subunits with covalently bound carbohydrate.
Abstract: Catalase from Aspergillus niger was purified to homogeneity as judged from the results of ultracentrifugation and polyacrylamide gel electrophoresis. The enzyme had a molecular weight of 385,000 as estimated from sedimentation measurements. Carbohydrate analyses showed that the catalase was a glycoprotein containing about 8.3% neutral sugar and 1.9% glucosamine. Under denaturing conditions, polyacrylamide gel electrophoresis revealed only one band with a molecular weight of 97,000 daltons in gels stained for either protein or sugar, suggesting that the native enzyme consists of four subunits with covalently bound carbohydrate. In the reaction with inhibitors, A. niger catalase showed lower affinity than the "standard" catalases. The pK values for HCN, HN3, and HF were estimated to be 3.4 (at pH 7.4), 2.3, and 1.5 (at pH 4.2), respectively. In addition, the fungal enzyme reacts with methyl hydrogen peroxide in a very unusual way. Even after the addition of a large excess of the peroxide, only catalase compound I was formed, and compound II did not appear. Using this unique property of A. niger catalase, we obtained CD and MCD spectra of compound I uncontaminated by compound II. The magnitude of the positive CD peak of compound I in the Soret region was about half that of the native enzyme. The MCD spectrum obtained was better resolved than that of bovine liver catalase compound I in the visible region.
70 citations
01 Jun 1982
TL;DR: A recently developed immobilization method, characterized by the adsorption of the mycelia onto a glass-carrier in a fixed-bed reactor, was applied for citric acid production by Aspergillus niger ATCC 9142, and compared with conventional culture techniques.
Abstract: A recently developed immobilization method, characterized by the adsorption of the mycelia onto a glass-carrier in a fixed-bed reactor, was applied for citric acid production by Aspergillus niger ATCC 9142, and compared with conventional culture techniques.
49 citations
TL;DR: The extensive action of the glucoamylase on potato starch exposed the 6-posphorylglucosyl residue of the starch at the non-reducing terminal and large molecular weight limit dextrins remained.
45 citations
TL;DR: The total polyol pool increased in both organisms in response to raised salinity, and the proportion of glycerol and erythritol was markedly enhanced at high salinity.
Abstract: The accumulation of polyols by Aspergillus niger (van Tiegh) strain S 1 and Penicillium chrysogenum (Thom) strain S 30 was followed during growth in media of different concentrations of NaCl. The major polyols found were glycerol, erythritol and mannitol. The total polyol pool increased in both organisms in response to raised salinity, and the proportion of glycerol and erythritol was markedly enhanced at high salinity.
44 citations
TL;DR: In this article, the conversion of 1, 8-cineole by a strain of Aspergillus niger was investigated in connection with the biomass utilization of Eucalyptus plants.
Abstract: Conversion of 1, 8-cineole (1) by a strain of Aspergillus niger was investigated in connection with the biomass utilization of Eucalyptus plants. Two novel alcohols, 3-exo-(5) and 3-endo-hydroxycineole (6) were isolated from the culture broth and identified by interpretations of their spectral data. Furthermore, hydrogenolysis of 6 afforded p-methane-3, 8-e"-diol (8) which has been isolated as a plant growth inhibitor from Eucalyptus citriodora.
39 citations
TL;DR: Aspergillus niger ATCC 9142 mycelium was entrapped in calcium alginate beads and employed in an air-lift completely stirred reactor for continuous production of citric acid.
Abstract: Aspergillus niger ATCC 9142 mycelium was entrapped in calcium alginate beads and employed in an air-lift completely stirred reactor for continuous production of citric acid. Maximum yield obtained from 10% (w/v) sucrose was 12 g dm-3 with about 40% fermentation efficiency. Maximum rate of production 70 mg g-1 h-1 was about five times that obtained in classical batch fermentation.
39 citations
TL;DR: The main finding is that the reaction rate is not linearly correlated to the enzyme concentration—it increase more than proportionally.
Abstract: The kinetics of glucose liberation from lactose by b-galactosidase from A. niger was studied in a wide range of the main variables. The anal. shows that the kinetic models proposed so far are not adequate. The main finding is that the reaction rate is not linearly correlated to the enzyme concn.; it increases more than proportionally. This nonlinear relation results because this lactase can distinguish between a- and b-galactose. a-Galactose acts as competitive and anticompetitive inhibitor, whereas b-galactose is a competitive one. The competitive inhibition of the a-anomer is .apprx.12 times more severe than that of the b-anomer. The kinetics, including a simplified model for the mutarotation of galactose is given for a temp. of 50 Deg at a pH of 3.5, the most likely conditions for the application of this lactase in acid whey treatment. [on SciFinder (R)]
37 citations
TL;DR: Quantitative product analysis of enzyme-substrate mixtures using 1-3H-reducing end-labeled xylooligosaccharides and [U-14C]xylotriose led to the following conclusions: bond cleavage frequencies of xylotruose, xylOTetraose and xylopentaose are strongly dependent on substrate concentration.
33 citations
TL;DR: Hydrophobic-ionic chromatography on an Amberlite CG-50 column is effective for the purification of various enzymes, provided that they are stable at the acidic pH.
Abstract: Glucose oxidase from Aspergillus niger, hyaluronidase from Streptomyces hyalurolyticus, and cholesterol oxidase and cholesterol esterase from Pseudomonas fluorescens were effectively adsorbed on an Amberlite CG-50 column, when the cell-free cultured medium or the cultured medium with cell extract and without cell debris was applied without desalting but at pH less than or equal to 4.5. At the acidic pH, all the ion-exchange groups (-COOH) exist in the protonated form; the adsorption is not due to electrostatic attraction, but to hydrophobic interaction. The enzymes thus adsorbed were effectively eluted by increasing pH, at which the ion-exchange groups became dissociated. This type of adsorption-elution is called hydrophobic-ionic chromatography. By a single run of chromatography, glucose oxidase, hyaluronidase, cholesterol oxidase, and cholesterol esterase were purified 30-fold, 12-fold, 45-fold, and 20-fold with yields of 82%, 83%, 80%, and 90%, respectively. This indicates that hydrophobic-ionic chromatography on an Amberlite CG-50 column is effective for the purification of various enzymes, provided that they are stable at the acidic pH.
32 citations
01 Mar 1982
TL;DR: Comparison of high and low yielding process parameters showed that under high yielding conditions, (deionized sugar, Cu++ addition) besides more citric acid, more mycelium and less mycelial lipids were formed; the consumption of sugar, nitrogen and phosphorus was related to the amount of biomass.
Abstract: The effect of changing the composition of a chemically defined medium on citric acid production by Aspergillus niger was investigated. High and reproducible amounts of citric acid were obtained with deionized commercial sugar solutions, proper phosphate concentrations, low initial pH values and suitable amounts of copper as growth inhibiting agent. Comparison of high and low yielding process parameters showed that under high yielding conditions, (deionized sugar, Cu++ addition) besides more citric acid, less mycelium and less mycelial lipids were formed; the consumption of sugar, nitrogen and phosphorus was related to the amount of biomass.
TL;DR: In this article, the triazolylmethane fungicides triadimefon, triadimenol, and diclobutrazol were studied using a replacement culture technique and 14C substrates.
TL;DR: The possibility of utilising mesophilic, efficient cellulolytic cultures for accelerating the process of composting for efficient recycling of dry, wide C/N ratio materials of a fairly homogeneous nature is indicated.
TL;DR: Culture of a strain of Aspergillus niger on medium containing 3 % tannic acid yielded tannase (tanin acylhydrolase), evidenced both in the culture medium and the mycelium.
Abstract: Culture of a strain of Aspergillus niger on medium containing 3 % tannic acid yielded tannase (tanin acylhydrolase), evidenced both in the culture medium and the mycelium. Fermentation in submerged culture at constant air flow gave mycelium with high tannase activity.
TL;DR: A very simple affinity chromatography technique of glucoamylase purification from a filtrate of A. niger C culture suggests an oligomeric structure of this enzyme, shown only as a glycoprotein of M, 50000-100000.
01 Dec 1982
TL;DR: The redox potential of the fermentation broth is the result of oxydo-reduction processes where the metabolic activity of the microorganism Aspergillus niger plays the most significant role.
Abstract: The role and importance of the redox potential phenomena in submerged citric acid production are discussed. The redox potential of the fermentation broth is the result of oxydo-reduction processes where the metabolic activity of the microorganism Aspergillus niger plays the most significant role. The course of the redox curve for a good yielding citric acid production is presented and interpreted. The experiments of submerged citric acid production were carried out on beet molasses treated with potassium hexacyanoferrate and inoculated with A. niger spores.
TL;DR: Immobilized glucoamylase showed decreased stability upon heating, compared with the soluble enzyme, suggesting that the lack of pores can eliminate the problem of product reversion.
01 Jan 1982
TL;DR: The exocellular alpha-amylase of a strain of Aspergillus niger was purified to homogeneity by gel electrophoresis and confirmed by sedimentation studies.
Abstract: The exocellular alpha-amylase of a strain of Aspergillus niger was purified to homogeneity. Its purity was established by gel electrophoresis and confirmed by sedimentation studies. The mol. wt. of the enzyme was 56 230. Its Km values on different starches, temp. and pH optima for activity and energy of activation were established. Compared to literature values for other fungal alpha-amylases, this enzyme exhibited a lower energy of activation, increased tolerance to lower pH and enhanced affinity to starch, highlighting its potential industrial application. While Ag-+, Pb-2-+, Hg-+, Al-3-+ and EDTA inhibited the activity of the enzyme, Ca-2-+ enhanced its activity, apart from conferring thermal stability and lowered activation energy. The products of its action on starch were maltooligosaccharides, maltose and glucose.
TL;DR: In this paper, the exocellular α-amylase of a strain of Aspergillus niger van Tieghem (elaborating both dextrifying and saccharifying thermophilic amylases) was purified to homogeneity.
Abstract: The exocellular α-amylase of a strain of Aspergillus niger van Tieghem (elaborating both dextrifying and saccharifying thermophilic amylases) was purified to homogeneity. Purification was achieved by providing cultural conditions for the organism to preferentially synthesize α-amylase and fractionation of the culture filtrate by DEAE-Sephadex chromatography. Its purity was established by gel electrophoresis and confirmed by sedimentation studies. The molecular weight of the enzyme was 56,230. Its Km values on different starches, temperature and pH optima for activity and energy of activation were established. Compared to literature values for other fungal α-amylases, this enzyme exhibited a lower energy of activation, increased tolerance to lower pH and enhanced affinity to starch, highlighting its potential industrial application. While Ag+, Pb2+, Hg+, Al3+ and EDTA inhibited the activity of the enzyme, Ca2+ enhanced its activity, apart from conferring thermal stability and lowered activation energy. The product of its action on starch were maltooligosaccharides, maltose and glucose.
Reinigung und Charakterisierung einer thermophilen α-Amylase aus Aspergillus niger van Tieghem.
Die extrazellulare α-Amylase eines Stammes von Aspergillus niger van Tieghem, der sowohl dextrinierende als auch verzuckernde thermophile Amylasen hervorbringt, wurde bis zur Homogenitat gereinigt. Die Reinigung wurde durch Einhalten der Kulturbedingungen zur bevorzugten Bildung von α-Amylase sowie durch Fraktionierung des Kulturfiltrates mittels DEAE-Sephadex-Chromatographie bewerkstelligt. Das Molekulargewicht des Enzyms betrug 56230. Seine KM-Werte (KM = Michaelis-Konstante) fur verschiedene Starken, Temperatur- und pH-Optima der Aktivitat sowie die Aktivierungsenergie wurden bestimmt. Verglichen mit anderen Pilz-α-Amylasen zeigte dieses Enzym eine niedrigere Aktivierungsenergie, erhohte Toleranz gegenuber niedrigeren pH-Werten sowie verstarkte Affinitat zu Starke. Wahrend Ag+, Pb2+, Hg+, Al3+ und EDTA die Aktivitat des Enzyms hemmten, erhohte Ca2+ seine Aktivitat. Die Produkte seiner Einwirkung auf Starke waren Maltooligosaccharide, Maltose und Glucose.
TL;DR: Growth of Aspergillus niger Van Tieghem in presence of 32p1 was followed by cell fractionation; the subcellular fractions were identified using marker enzymes and their phospholipid content was analyzed.
TL;DR: Cultivation of Aspergillus niger 97A in baffled flasks on a shaker brings about metabolic changes demonstrated in increased citric acid biosynthesis, morphological changes and alterations in the mycelial cell wall.
Abstract: Cultivation ofAspergillus niger 97A in baffled flasks on a shaker brings about metabolic changes demonstrated in increased citric acid biosynthesis, morphological changes and alterations in the mycelial cell wall.
TL;DR: The yield from glucose or starch hydrolysate was acceptably high in both shake and semi-solid fermentation indicating that the semi- solid fermentation process offers a promising practical alternative to the still fermentation process.
Abstract: A strain of Aspergillus niger was grown in still (liquid), shake and semi-solid fermentation for calcium gluconate production from glucose, starch, or molasses. The yield from glucose or starch hydrolysate was acceptably high in both shake and semi-solid fermentation indicating that the semi-solid fermentation process offers a promising practical alternative.
TL;DR: The effect of different concentrations of cysteine, serine, lysine, aspartic acid, and glutamic acid on the growth and fermenting activity of Aspergillus niger AL 29 was studied at different incubation periods.
Journal Article•
TL;DR: An investigation of transglucosidase thermal stability led to the observation that glycerol serves as a glucosyl acceptor and the transferase activity was measured using two independent assays containing α-methyl-D-gl glucoside and α-MG.
Abstract: An investigation of transglucosidase thermal stability led to the observation that glycerol serves as a glucosyl acceptor. The transferase activity was subsequently measured using two independent assays containing α-methyl-D-glucoside (α-MG) and α-MG + glycerol. The difference between values for digests with and without glycerol was then calculated giving the percentage of transfer to glycerol.
TL;DR: A considerable lowering of aeration demands occurs during diffuse growth of citric acid-producingAspergillus niger in a submerged cultivation, however, the diffuse culture poses stricter demands on the type of Aeration and agitation.
Abstract: A considerable lowering of aeration demands occurs during diffuse growth of citric acid-producing Aspergillus niger in a submerged cultivation. However, the diffuse culture poses stricter demands on the type of aeration and agitation. The impeller frequency affects considerably the morphology of the producer fungus and the accumulation of citric acid. The effect of impeller frequency on the distribution of air in the medium and on the amount of air fed into the diffuse culture is less important.
TL;DR: The derivation of Aspergillus niger strains having a lower standard deviation in citric acid production by the use of 60Co gamma radiation and by the parasexual cycle seems to be sufficient for reducing variability.
Abstract: We report the derivation of Aspergillus niger strains having a lower standard deviation in citric acid production by the use of 60Co gamma radiation and by the parasexual cycle. On the basis of the results obtained by isolating diploids and segregants, diploidization seems to be sufficient for reducing variability. The implications of these results in terms of improvement of industrial strains are discussed.
TL;DR: The hydrolysis of plumieride to form the aglycone plumieridine was catalysed by a commercial preparation of cellulase from Aspergillus niger.
TL;DR: Both soluble cellulose (CMC) and cotton cellulose treated with phosphoric acid (swollen) were easily hydrolyzed by cellulase; an increase in cellulase concentration lead to more hydrolysis of CMC and gave linearity in the reaction velocity.
Abstract: Cellulase enzyme was produced by a selected strain of Aspergillus niger isolated from deteriorated wood and grown on different carbon sources. Filter paper gave the highest yield, followed by carboxymethyl cellulose (CMC). Cellobiose as well as glucose gave a low yield, while the yield from lactose was negligible. The concentration of filter paper cellulose that induced the maximum yield of the enzyme was 1%. Both soluble cellulose (CMC) and cotton cellulose treated with phosphoric acid (swollen) were easily hydrolyzed by cellulase; an increase in cellulase concentration lead to more hydrolysis of CMC and gave linearity in the reaction velocity. At certain concentrations of the enzyme, increase in CMC concentration, (up to 1%) resulted in more reducing sugar. Beyond this point no more hydrolysis occur.
TL;DR: Aspergillus niger van Tieghem microsomes contain an enzyme that catalyzes mannose transfer from GDP-mannose to polyprenylphosphate, which has the specificity for both the sugar and the base very strict.