Showing papers on "Aspergillus niger published in 1969"
TL;DR: The enzymes were highly specific for the anomeric configuration of the glycosidic linkage and reasonably stable around their pH optima, which varied between 3.2 to 4.6.
166 citations
TL;DR: Two forms of the glucoamylase of Asgillus niger have been purified by chromatography on DEAE-cellulose ion-exchange columns and possessed a high degree of purity as indicated by paper electrophoresis, sedimentation velocity, and disc-gel electrophoreis.
86 citations
TL;DR: The activities of two glutamate dehydrogenases, one requiring NAD and the other specific for NADP, and of aspartate and alanine amino transferases varied during growth as a function of the stage of the life cycle and of the growth medium, finding no clear correlation between the activities of these enzymes and conidiation of this fungus.
Abstract: SUMMARY: Asexual sporulation of Aspergillus niger occurred in submerged culture in a liquid minimal medium without added nitrogen, in low ammonium-N concentrations, and in a wide range of nitrate-N concentrations. Ammonium salts containing more than 48 mg. atom N/l. were inhibitory to conidiation. Most amino acids overcame the ammonium inhibition of conidiation when added to an ammonium nitrate medium. Glyoxylate and several intermediates of the tricarboxylic acid (TCA) cycle also promoted conidiation in the presence of ammonium. Changes in the medium of conidiating and non-conidiating cultures were examined with respect to nitrogen and glucose concentrations, dry weight and pH value. The activities of two glutamate dehydrogenases, one requiring NAD and the other specific for NADP, and of aspartate and alanine amino transferases varied during growth as a function of the stage of the life cycle and of the growth medium. There was no clear correlation between the activities of these enzymes and conidiation of this fungus.
66 citations
TL;DR: Pyruvate carboxylase was partially purified from Aspergillus niger and the properties were studied, and the enzyme was shown to be a biotin-containing enzyme by its in activation by avidin and protection against such inactivation by biotin.
Abstract: Pyruvate carboxylase was partially purified from Aspergillus niger and the properties were studied. The enzyme was found to be cold-labile and protected by 25% glycerol. The pH optimum was determin...
63 citations
TL;DR: The morphology of Aspergillus niger van Tieghem in submerged culture was affected by the pH of the medium, and agglutination of spores was shown to be a vital process, believed to be caused by changes in the spore surface associated with swelling.
Abstract: The morphology of Aspergillus niger van Tieghem in submerged culture was affected by the pH of the medium. At pH values below 2·3 growth was filamentous, whereas pellets formed in more alkaline conditions. The character of the pellet varied with pH. There was no difference between pellet and filamentous cultures in dry weight or pH curves, or rate of glucose or ammonium uptake. Pellet development was initiated by agglutination of the conidia, which begins at the same time as spore swelling and the appearance of germ tubes. Later, agglutination of clumps of spores occurred, possibly through germ tubes intertwining. Agglutination of spores was shown to be a vital process, believed to be caused by changes in the spore surface associated with swelling. Surface charge is not considered to be an important factor.
48 citations
TL;DR: It is proposed that isocitrate lyase is functional in glycine synthesis and that a source of glyoxylate may be indispensable to the expression of sporulation.
Abstract: The activities of certain enzymes of the tricarboxylic acid (TCA) cycle and the glyoxylate cycle (GLC) varied during growth of Aspergillus niger as a function of the stage of the life cycle and of the growth medium. Isocitrate dehydrogenase (carboxylating) and isocitrate lyase each showed a marked increase in activity prior to sporulation. There were no similar increases in vegetative cultures. It is proposed that isocitrate lyase is functional in glycine synthesis and that a source of glyoxylate may be indispensable to the expression of sporulation.
35 citations
TL;DR: Polysaccharides were separated from mycelia and culture filtrates of the filamentous fungi Aspergillus niger and Penicillium chrysogenum, and purified by column chromatography on Sephadex G-50, DEAE- and CM-cellulose, and confirmed to be galactomannans.
Abstract: Polysaccharides were separated from mycelia and culture filtrates of the filamentous fungi Aspergillus niger and Penicillium chrysogenum, and purified by column chromatography on Sephadex G-50, DEAE- and CM-cellulose, successively. No nitrogen and phosphorus were detected in the polymer, and the sugar components were observed to be galactose and mannose. The polysaccharides were confirmed to be galactomannans which were easily hydrolyzed by weak acid, liberating galactofuranose and oligosugar in dialyzable fractions.
31 citations
31 citations
TL;DR: Comparison of the ‘maps’ of peptic peptides indicate that there may be some homology between the wall proteins of the two fungi.
Abstract: SUMMARY: Cell-wall fractions were obtained from Aspergillus niger and Chaetomium globosum. Non-structural protein was removed by successive washes in urea, NH4OH and formic acid. Amino acid analyses indicated that structural wall proteins were acidic. Aspartic acid was the free amino terminal residue of the protein in both species. Comparison of the ‘maps’ of peptic peptides indicate that there may be some homology between the wall proteins of the two fungi.
30 citations
TL;DR: The characteristics of glucoamylase synthesis were not specific for this strain since similar results were obtained with A. niger NRRL 3122 and A. awamori NRRL 3112.
Abstract: Glucoamylase produced by Aspergillus niger was observed to increase in culture media at two specific intervals, namely, after three days and after six days of incubation. The lowest levels of enzyme production occurred when the nitrogen source was asparagine, trypticase or urea. Intermediate quantities of enzyme were formed when the fungi were grown on a nitrogen source of yeast extract. Corn steeping liquor and nutrient broth (2.5%) gave highest enzyme activity. The inorganic nitrogen source providing the best glucoamylase yield was ammonium-N. Nitrate-N or a mixture of ammonium-N and nitrate-N was less effective. When inorganic nitrogen was employed, the two periods of glucoamylase production were not as readily demonstrated. With ammonium-N, all the glucoamylase is produced during the fourth or fifth day of incubation, thus showing only one period of enzyme synthesis.The quantity of glucoamylase produced depended upon the monosaccharide added to the growth medium. Glucose yielded the highest level of enzyme regardless of the nitrogen sources. Mannose, usually, was slightly more effective than sorbitol and produced about half the quantity of glucoamylase obtained from glucose. Lowest levels of enzyme occurred when fructose or xylose served as carbon sources. Growth on 1.0 or 2.0% carbohydrate, rather than 5.0%, was found to result in higher levels of glucoamylase. Although A. niger NRRL 330 was the principle organism tested, the characteristics of glucoamylase synthesis were not specific for this strain since similar results were obtained with A. niger NRRL 3122 and A. awamori NRRL 3112.
29 citations
Journal Article•
TL;DR: Experiments show that the presence of herbicide residues in plant remains may be a potent factor determining the outcome of competition between saprophytic fungi colonizing such substrates.
Abstract: Summary
Experiments show that the presence of herbicide residues in plant remains may be a potent factor determining the outcome of competition between saprophytic fungi colonizing such substrates. Pairs of fungi were induced to compete with each other for a substrate both in the presence and in the absence of herbicides. In all cases the outcome of competition for a substrate incorporating the herbicide was different from that for the substrate alone. Paraquat sprayed on to potato haulm altered the outcome of competition between Trichoderma viride and Fusarium culmorum in favour of F. culmorum and the same herbicide on wheat chaff suppressed Rhizopus stolonifer in favour of Aspergillus niger. Treatment of leaves of Raphanus raphanistrum with MCPA altered the outcome of competition between Fenicillium notatum and Aspergillus niger in favour of A. niger.
TL;DR: Inhibition of growth and sporulation of Aspergillus niger and germination of seeds of Lepidium sativum could be produced by these culture gas concentrations of acetaldehyde and of ethanol and of 3-methyl-butan-1-ol to a lesser extent.
Abstract: SUMMARY: The gas mixtures from cultures of Saccharomyces cerevisiae inhibited growth and sporulation of Aspergillus niger and germination of seeds of Lepidium sativum. In test conditions seven volatile organic metabolites in the culture gases were identified by gas-liquid chromatography (GLC) as acetaldehyde, ethyl acetate, ethanol, n-propanol, isobutanol, and a mixture of isopentanols (1 part 2-methyl-butan-1-ol to 2 parts 3-methyl-butan-1-ol); changes in the concentrations of CO2 and O2 were also measured. Pure samples of each of these components were tested at the concentrations found in the culture gases in order to identify the inhibitory substances.
Inhibition of growth of Aspergillus niger could be produced by these culture gas concentrations of acetaldehyde and of ethanol. Inhibition by this concentration of CO2 was just significant in these tests. The effect on sporulation could be produced by the CO2, but not by these concentrations of any of the other identified components.
The effect of Lepidium sativum seed germination could be produced by these culture gas concentrations of ethanol and of 3-methyl-butan-1-ol to a lesser extent. Slight effects were also observed with a lowered O2 concentration and with a raised CO2 concentration but not with the other constituents.
TL;DR: The enzyme catalyzed the stoichiometric formation of protocatechuic acid (3,4-dihydroxybenzoic acid) from m-hydroxylase with the consumption of NADPH and molecular oxygen and showed a requirement for FAD.
Abstract: m-Hydroxybenzoic acid 4-hydroxylase was isolated and partially purified from Aspergillus niger grown in presence of m-hydroxybenzoic acid. The enzyme catalyzed the stoichiometric formation of protocatechuic acid (3,4-dihydroxybenzoic acid) from m-hydroxybenzoic acid with the consumption of NADPH and molecular oxygen. The reaction proceeded best at pH 7.2 and showed a requirement for FAD.
TL;DR: Phosphogluconate dehydrogenase was purified about 20 fold from an adapted strain of Aspergillus niger cultivated on gluconate as the sole carbon source and showed pH optimum between 7.0 to 7.6.
Abstract: A citric acid accumulating strain of Aspergillus niger adapted to grow on gluconic acid lactone as sole carbon source was studied with regards to the enzymatic changes occurring during its adaptive growth and compared with those of the parent strain cultivated on sucrose.
TL;DR: The fungi isolated from 100 samples of flue-cured tobacco from 12 markets in 2 tobacco belts comprised 11 genera, including 10 species of Aspergillus, whereas species of Alternaria, Cladosporium, Fusarium, and Rhizopus were isoalted more frequently from nondamaged tobacco.
Abstract: The fungi isolated from 100 samples of flue-cured tobacco from 12 markets in 2 tobacco belts comprised 11 genera, including 10 species of Aspergillus. The mean percentage per sample isolated from 62 samples of tobacco from Middle Belt markets was Alternaria, 40.6%; Aspergillus niger, 47.8%; Aspergillus repens, 38.0%; and Penicillium, 25.8%. The mean percentage per sample isolated from 38 samples of tobacco from Old Belt markets was Alternaria, 74.0%; Penicillium, 52.5%; Aspergillus repens, 38.0%; and Aspergillus ruber, 36.2%. Damaged (74 samples) and nondamaged (26 samples) stored tobacco yielded species of six genera of fungi, including eight species of Aspergillus. Species of Aspergillus and Penicillium were commonly isolated from both damaged and nondamaged tobacco, whereas species of Alternaria, Cladosporium, Fusarium, and Rhizopus were isoalted more frequently from nondamaged tobacco. The fungi that occurred in the highest population in damaged tobacco were Aspergillus repens, A. niger, A. ruber, and Penicillium species.
TL;DR: Enzymes which contain carbohydrate units as integral structural components are appropriately designated as glycoenzymes and data on the properties of glucohydrolase isolated from inside and outside the cell establish that the carbohydrate moieties become attached to the enzyme inside the cell rather than during transport of the enzyme through the cell membrane and wall.
TL;DR: A new anthranilic acid hydroxylase which catalyzes the conversion of anthranic acid to 2,3-dihydroxybenzoic acid, has been partially purified from crude extracts of the mycelial felts of Aspergillus niger, grown in the presence of anthanilic acid.
TL;DR: The facile formation of styrene has been confirmed, and phenylethylene glycol has been shown to be a metabolite for the first time in any system.
TL;DR: Two additional hydroxylated products of cinerone have been isolated and identified as 2-n-butyl-4-hydroxy-3-methyl-2-cyclopenten-1-one and 2-(2'-cis-butenyl- 4'-hydroxy)-3- methyl-2
Abstract: Cinerone [2-(2'-cis-butenyl)-3-methyl-2-cyclopenten-1-one] is hydroxylated to cinerolone [2-(2'-cis-butenyl)-3-methyl-4-hydroxy-2-cyclopenten-1-one] by a number of streptomycetes, bacteria, and fungi. Aspergillus niger ATCC 9,142 and Streptomyces aureofaciens ATCC 10,762 were found to be the most effective hydroxylators. The optical activity of the product was found to range from [alpha](D) (25) 0 degrees to -8.6 degrees , depending on the organism and conditions of culture. Two additional hydroxylated products of cinerone have been isolated and identified as 2-n-butyl-4-hydroxy-3-methyl-2-cyclopenten-1-one and 2-(2'-cis-butenyl-4'-hydroxy)-3-methyl-2-cyclopenten-1-one, respectively.
TL;DR: Among 20 locally isolated fungi, Aspergillus niger isolate no. 58 proved to be suitable for the production of active extracellular milk-clotting enzyme and the addition of acetate buffer to the reaction mixture enhanced the clotting of milk by the enzyme whereas citrate + phosphate buffer hindered the process.
Abstract: SUMMARY: Among 20 locally isolated fungi, Aspergillus niger isolate no. 58 proved to be suitable for the production of active extracellular milk-clotting enzyme. The addition of acetate buffer to the reaction mixture enhanced the clotting of milk by the enzyme whereas citrate + phosphate buffer hindered the process. The general properties of the crude enzyme were studied. Precipitation with ammonium sulphate, ethanol, acetone and tannin showed that ammonium sulphate was unsuitable for precipitation while the other precipitants produced sufficiently active fractions.
Patent•
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TL;DR: An acid-active, acid-stable lactose enzyme preparation derived from the growth of a culture of Aspergillus niger and suitable for the hydrolysis of lactose in acid media is described in this article.
Abstract: An acid-active, acid-stable lactose enzyme preparation derived from the growth of a culture of Aspergillus niger and suitable for the hydrolysis of lactose in acid media
TL;DR: The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes, since the pH remained close to neutrality throughout the entire process.
Abstract: In this study, retting was carried out by Aspergillus niger. The pH, galacturonic acid (GA), and total reducing sugar were determined; the end point was identified by the classic empirical processes and by the maximal GA content of the retting water. The process gave clear and resistent fibers, and the retting time was similar to that of current industrial processes with bacterial enzymes. Control of total acidity was not required, since the pH remained close to neutrality throughout the entire process.
TL;DR: The effects of two nutritional elements and two environmental factors on growth and sclerotial production of Aspergillus niger were determined on a syntheti...
Abstract: The effects of two nutritional elements (carbon and sulfur) and two environmental factors (pH and temperature) on growth and sclerotial production of Aspergillus niger were determined on a synthetic agar medium. The fungus grew and produced sclerotia under laboratory conditions on media containing wide ranges of carbon and sulfur sources. Of the 20 carbohydrates tested, only ribose, mannitol, and malonic, fumaric, and citric acids failed to induce production of sclerotia. A synergistic effect was observed on the formation of sclerotia when favorable and unfavorable carbon sources were supplied in different combinations. Of the 14 sulfur compounds tested, magnesium sulfate yielded the highest and sodium sulfite the lowest number of sclerotia. Raising the concentration of magnesium sulfate to 3 g/l increased the number of sclerotium initials and the number and dry weight of those which matured. In general, no correlation occurred between the number of sclerotia formed and their dry weights on different carb...
TL;DR: A strain of A. niger, adapted to grow on Sorbitol is cultivated on a medium containing sorbitol as the sole carbon source, and ammonium nitrate was found to be the best source of nitrogen.
TL;DR: The frequency of transformation was low which could be attributed to the method of extraction of DNA which involved crushing of cells in the presence of alumina, possibly breaking the DNA into small fragments thus making it biologically less active.
Abstract: SUMMARY: Reversions to wild type occurred when conidia of a number of biochemically deficient mutants of Aspergillus niger were treated with DNA from the wild-type strain. No reversions or wild-type colonies were obtained when an equivalent number of conidia from deficient strains were either treated with the same DNA as the recipient, or were plated without any DNA treatment. Increase in the percentage of transformation was observed up to 6 μg./ml. of donor DNA. The transforming activity of the donor DNA was found to be inhibited by the action of u.v. radiation, heat and DNase. The frequency of transformation was low which could be attributed to the method of extraction of DNA which involved crushing of cells in the presence of alumina, possibly breaking the DNA into small fragments thus making it biologically less active.
Patent•
25 Nov 1969
TL;DR: Gluconic acid is produced by a fermentation process in which an inoculum of the fungus Aspergillus niger is transferred to a first production medium containing a source of glucose at a time when the glucose oxidase activity of the inoculum is increasing at its maximum rate as mentioned in this paper.
Abstract: Gluconic acid is produced by a fermentation process in which an inoculum of the fungus Aspergillus niger is transferred to a first production medium containing a source of glucose at a time when the glucose oxidase activity of the inoculum is increasing at its maximum rate. The fungus mycelium can be separated from the production medium at harvest time and reused in successive production media without the need for added nutrients until such time as nutrients are needed to revive the glucose oxidase activity.