Showing papers on "Aspergillus niger published in 1981"
TL;DR: In this article, Aspergillus awamori NRRL 3112 and A. niger amyloglucosidase were used as Koji enzymes to reduce the viscosity of cassava root fermentation mashes.
Abstract: Raw cassava root starch was transformed into ethanol in a one-step process of fermentation, in which are combined the conventional processes of liquefaction, saccharification, and fermentation to alcohol. Aspergillus awamori NRRL 3112 and Aspergillus niger were cultivated on wheat bran and used as Koji enzymes. Commercial A. niger amyloglucosidase was also used in this experiment. A raw cassava root homogenate-enzymes-yeast mixture fermented optimally at pH 3.5 and 30/degree/C, for five days and produced ethanol. Alcohol yields from raw cassava roots were between 82.3 and 99.6%. Fungal Koji enzymes effectively decreased the viscosity of cassava root fermentation mashes during incubation. Commercial A. niger amyloglucosidase decreased the viscosity slightly. Reduction of viscosity of fermentation mashes was 40, 84, and 93% by commercial amyloglucosidase, A. awamori, and A. niger enzymes, respectively. The reduction of viscosity of fermentation mashes is probably due to the hydrolysis of pentosans by Koji enzymes. 12 refs.
107 citations
TL;DR: It is suggested that the multiplicity of the enzyme is due to variation in the carbohydrate and their structures, rather than in the protein moiety.
88 citations
TL;DR: A xylanase from a commercial Aspergillus niger pentoglycanase was purified to homogeneity by column chromatography on Ultrogel AcA 54, SP-Sephadex, SephadeX G-50, and SP-Octanex to achieve maximal activity.
72 citations
TL;DR: In this paper, two strains of Aspergillus niger of different productivity were analyzed from a high number of data points and the observed differences in productivity of the two strains are reflected by the different non-growth-associated terms of the equation.
Abstract: Citric acid fermentation on pilot plant scale was studied, using two strains of Aspergillus niger of different productivity. Growth and product formation were analyzed from a high number of data points. Several phases could be distinguished which were described by a sequence of logarithmic, cube-root, and linear equations. Growth and product formation could be related by a modified Luedeking-Piret equation, taking into consideration a lag time for the organism to shift to shift into the physiological state ready for product formation. The observed differences in productivity of the two strains are reflected by the different non-growth-associated terms of the equation. In light of these findings the classical "type II fermentation" is redefined as a mixed type–resembling type I during trophophase and type III during idiophases.
56 citations
TL;DR: From the variation of kinetic parameters with pH, it is concluded that the Mannitol-1-phosphate dehydrogenase contains one amino acid residue with pKa 9–10 which is involved in binding of fructose-6- phosphate, and another amino acid residues with p Ka about 8.2 which are involved in catalysis.
51 citations
TL;DR: It is concluded that cotton waste can be used for saving sucrose and for increasing yields of citric acid fermentation by Aspergillus niger.
Abstract: The possible use of cotton waste as a carbohydrate source of citric acid production by Aspergillus niger was examined. No citric acid was produced when A. niger was grown on cotton waste as a sole carbon source. In two-stage fermentations, however, mycelium obtained from surface cultures in cotton waste medium yielded more citric acid when transferred to sucrose-containing media than when directly inoculated to sucrose-containing media. It is concluded that cotton waste can be used for saving sucrose and for increasing yields of citric acid fermentation by A. niger.
48 citations
TL;DR: Catalase from Aspergillus niger was isolated from a commercial preparation and was found to be glycoprotein containing 9% neutral sugar and 3% hexosamine, which was markedly more stable than the beef liver enzyme to inactivation by heat, proteolysis, and glutaraldehyde modification.
45 citations
TL;DR: A high-d-xylulose mixture was prepared from the cold ethanol extract of preisomerized d- xylose solution and Fusarium oxysporum f.
Abstract: A high-d-xylulose mixture (d-xylose-d-xylulose = 33:67) was prepared from the cold ethanol extract of preisomerized d-xylose solution (d-xylose-d-xylulose = 77:23). Fusarium oxysporum f. sp. lini and Aspergillus niger were demonstrated to preferentially utilize d-xylose in the mixture of d-xylose and d-xylulose. Chromatographically pure d-xylulose was thus obtained in 90% yield. A high-d-xylulose mixture was also incubated with Rhodotorula toruloides, Klebsiella pneumoniae, Candida utilis, or Mucor rouxii.d-Xylose and d-xylulose were simultaneously consumed. When borate was added to the mixture, a d-xylulose-borate complex was formed, and it could be used to protect d-xylulose from being utilized.
42 citations
TL;DR: In this paper, Aspergillus niger JTS 191 was selected from many microorganisms tested as capable of converting ionones to other compounds having aromas, and individual transformation products from β-ionone were isolated and identified by comparison with synthetically derived compounds.
Abstract: Aspergillus niger JTS 191 was selected from many microorganisms tested as capable of converting ionones to other compounds having aromas. The individual transformation products from β-ionone were isolated and identified by comparison with synthetically derived compounds. The major products were (R)-4-hydroxy-β-ionone and (S)-2-hydroxy-β-ionone. 2-Oxo-, 4-oxo-, 3,4-dehydro-, 2,3-dehydro-4-oxo-, 3,4-dehydro-2-oxo-, (S)-2-acetoxy-, (R)-4-acetoxy-, and 5,6-epoxy-β-ionone and 4-(2,3,6-trimethylphenyl)-but-3-en-2-one were also identified. Analogous transformation products of β-methylionone also were identified. Based on gas-liquid chromatographic analysis during the fermentation, we propose two main oxidative pathways of β-ionone. The results of this study suggest that these transformations of β-ionones may be useful as tobacco-flavoring compounds.
39 citations
TL;DR: This article corrects the article on p. 594 in vol.
Abstract: 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.
37 citations
TL;DR: Some molecular and regulatory properties of two malate dehydrogenase isoenzymes from A. niger are reported, which are involved in a shuttle mechanism which transports reduced NADH across the mitochondrial membrane and thereby generates mitochondrial oxaloacetate.
Abstract: The accumulation and excretion of citric acid by Aspergillus niger is a notable example of fungal 'over-flow' metabolism, and for 30 years has been the world's primary source of citric acid. However, the biochemical information available on this process has to date not permitted its elucidation, but recently certain regulatory steps of A. niger energy metabolism have been investigated with respect to citric acid accumulation [ 1-4]. Malate dehydrogenase (EC 1.1.1.37) isoenzymes of A. niger were investigated because of the key role of oxaloacetate in the accumulation of citric acid [5]. They are involved in a shuttle mechanism which transports reduced NADH across the mitochondrial membrane and thereby generates mitochondrial oxaloacetate. On the other hand, there is a very active pyruvate carboxylase (EC 6.4.1.1), located intramitochondrially [6], whose activity in vivo has been shown to be strongly correlated with citric acid accumulation [7]. The present paper reports some molecular and regulatory properties of two malate dehydrogenase isoenzymes from A. niger. 2.1. Organism and conditions for growth
01 Jan 1981
TL;DR: In this paper, a process for the production of citric acid by Aspergillus niger in a single-stage continuous culture is presented, where citric acids are produced under nitrogen limiting conditions.
Abstract: A process for the production of citric acid by Aspergillus niger in a single-stage continuous culture is presented. The citric acid is produced under nitrogen limiting conditions. The process has been investigated in the dilution rate range 0.05 to 0.20 h−1 and the citric acid concentration increases rapidly with decreasing dilution rate. Citric acid production is greatly affected by the medium composition and operational parameters. The continuous process represents a considerable increase in productivity from the batch process.
01 Jan 1981
TL;DR: Fermentation of acid-whey permeate by a mutant strain (A. niger 599-3) was more reproducible, and yields of citric acid were substantially improved, and galactose was apparently co-metabolized with glucose.
Abstract: Acid-whey permeate was used for the production of citric acid by Aspergillus niger. The fermentation proceeded in 2 phases: a growth phase when citric acid was not accumulated, followed by an acidogenic phase when citric acid accumulated and mold growth was greatly reduced. Optimal production of citric acid occurred after 8-12 days at 30 degrees. Maximum citric acid yields were influenced by the initial lactose concentration and reached 10 g/l when the lactose concentration in the acid-whey permeate was adjusted to 15%. MeOH at 2-4% markedly increased the production of citric acid. Fermentation of acid-whey permeate by a mutant strain (A. niger 599-3) was more reproducible, and yields of citric acid were substantially improved. The amount of citric acid produced by A. niger 599-3 was 18-23 g/l after 12-14 days, depending on the lactose content of the whey permeate. Throughout the fermentation, galactose was apparently co-metabolized with glucose.
TL;DR: Unexpected germination in the form of spherical cells in A. niger during early stages of development in a high citric acid yielding medium is described.
Abstract: Numerous papers have dealt with the fermentation technology of citric acid production by Aspergillus niger but relatively few have described morphological properties of the mould during the fermentation. Manganese deficiency which induced good citric acid yields and affected the morphology of pellets was described by Clark et al. [1]. Recently impaired germination in Mn 2+ deficient medium was reported by Kisser et al. [2]. The present paper describes unusual germination in the form of spherical cells in A. niger during early stages of development in a high citric acid yielding medium. The appearance of spherical bulbous cells and later changes in morphology indicated some correlation to dimorphism found in some other fungi [3]. In Aspergillus dimorphism was found in A. parasiticus [4] in a Mn 2+ deficient medium and some similarity to this phenomenon has been described in A. niger where giant cells developed at elevated temperature [5].
TL;DR: Effect of inoculation with Glomus fasciculatus, Beijerinckia mobilis and Aspergillus niger, singly and in combination, on growth and nitrogen and phosphorus content of onion was studied.
Abstract: SUMMARY Effect of inoculation with Glomus fasciculatus, Beijerinckia mobilis and Aspergillus niger, singly and in combination, on growth and nitrogen and phosphorus content of onion was studied. Inoculation with G. fasciculatus or B. mobilis increased the dry wt and nitrogen content of the plant. A. niger inoculation had no significant influence on plant growth. B. mobilis inoculation stimulated the sporulation by VA mycorrhizas. Synergistic beneficial effect due to inoculation with all the three organisms was observed.
TL;DR: The results suggest that the decreased enzyme activity observed during growth in the presence of tunicamycin is due to a reduced amount of enzyme.
TL;DR: The acid carboxypeptidase was found to be an acidic glycoprotein (pI, 4.4.1), composed of 955 amino acid, 140 mannose, 14 galactose and 30 glucosamine residues/molecule, suggesting that the native enzyme is composed of two identical subunits.
TL;DR: The purified Aβ-Galactosidase appears to be a glycoprotein and may contain multiple molecular forms and may be suitable for immobilization and hydrolysis of lactose.
Abstract: β-Galactosidase (A. niger) was purified from a commercial source in order to study the protein nature of the enzyme and some of its kinetic properties. The enzyme was rapidly purified by acetone precipitation, gel filtratior, and affinity chromatography. The specific activity of the purified enzyme was twice as high as that found in previous studies. The Km and Vmax for o-nitrophenyl β-D-galactopyranoside were 2.02 mM and 345 μmoles/min/mg protein respectively at pH 4.5 and 37°C. The procedure described yields a highly active enzyme which may be suitable for immobilization and hydrolysis of lactose. The molecular weight of the enzyme was 117,000 and the isolectric point was 4.9. The enzyme appears to be a glycoprotein and may contain multiple molecular forms.
TL;DR: The previously unobserved morphology of the sporulating structures produced was much simplified under nitrate limitation, but similar to sub-aerial morphology under carbon limitation, which was found to be ideal for controlling organism morphology and thus sporulation.
Abstract: Sporulation of Aspergillus niger and Aspergillus ochraceus was induced in a continuous tower fermenter by restricting growth by nutrient limitation. Shock carbon limitation produced no sporulation, but the gradual decrease of sucrose or starch supply to A. niger produced slight sporulation. Gradual nitrate limitation produced no sporulation, while a shock decrease in nitrate concentration caused heavy sporulation of both organisms. The previously unobserved morphology of the sporulating structures produced was much simplified under nitrate limitation, but similar to sub-aerial morphology under carbon limitation. Maintenance energy values for sucrose and starch were calculated for A. niger and for starch for A. ochraceus. The continuous tower fermenter system was found to be ideal for controlling organism morphology and thus sporulation.
TL;DR: Aspergillus niger, strain 110.42 (CBS), has been selected as a producer of high xylanolytic activities and HPLC analysis of the enzymatic degradation of arabinoxylan showed a nearly complete conversion to pentose sugars.
Abstract: Aspergillus niger, strain 110.42 (CBS), has been selected as a producer of high xylanolytic activities. The time course of xylanase and β-xylosidase production as well as the effect of pH and temperature on the activity of these enzymes were studied. HPLC analysis of the enzymatic degradation of arabinoxylan showed a nearly complete conversion to pentose sugars. Aspects of using crude xylanase preparations for enzymatic saccharification of xylans are discussed.
01 Jun 1981
TL;DR: It was shown that in the period of mycelium growth the maximal activities of the enzymes were much higher in submerged culture than in surface culture.
Abstract: The activities of ACH1, NAD-ICDH, NADP-ICDH and CS were determined in cell extracts of high and low citric acid-producing strains of A. niger, cultivated on molasses medium by the surface or submerged method. A high differentiation in the activities of the enzymes studied was found to occur at various accumulation stages of citric acid and during its decomposition by moulds. During intensive citric acid synthesis, the activity of ACH and that of both dehydrogenases decreased significantly (though they did not disappear completely) compared to their initial activities during the growth period of the mycelium. CS activity, however, was maintained at almost the same level over the whole fermentation period or increased slightly, particularly in the case of low citric acid-producing strains. The relationships between the activities of these enzymes were reversed during citric acid decomposition by moulds.
TL;DR: Immobilization of the enzyme invariably led to decreased activity, the extent of the decrease being inversely proportional to the chain length of the spacer, which indicated that steric hindrance and, probably, diffusion effects are responsible for the decrease in activity.
TL;DR: The enzyme released expected amino acids sequentially from the carboxyl ends of S-beta-aminoethylated ribonuclease A and the B-chain of oxidized insulin, demonstrating carboxypeptidase activity of the enzyme.
TL;DR: The time required for glucose determination with a glucose oxidase reagent was significantly shortened by the addition of aldose 1-epimerase.
TL;DR: Wheat bran was the best cereal by-product forSCP production and compared favourably with glucose as a carbon source for SCP production by A. niger and A. terreus grown on wheat-bran medium.
TL;DR: The hexose fraction of the sulphitated syrup is much more inhibitory than the hexose fractions of unsulphitated syrup, indicating enhanced activity of the inhibitor at this step of cane-juice processing in sugar-mills.