| | 2 | Author
| H. Eikmeier, H. J. Rehm | Requires cookie* | | | Title
| Semicontinuous and Continuous Production of Citric Acid with Immobilized Cells of Aspergillus niger  | | | | Abstract
| The citric acid excretion of Ca-alginate-immobilized cells of Aspergillus niger in batch culture decreased with a half-time of approximately 19 days. Reactivation of the biocatalysts by regenera tion in growth medium was possible, but it was followed by a submerged sporulation of the fungus, and medium was highly contaminated with free cells. Citric acid production could better be prolonged by semicontinuous cultivation with medium exchange every 7 or 14 days, respective ly. After 32 days the remaining activity in semicontinuous culture was 1.4-fold higher than in comparable batch experiments. Similar improvements were obtained with a continuous process at a dilution rate of 0.125 v/v • d, whereby medium efflux | | | |
Reference
| Z. Naturforsch. 42c, 408—413 (1987); received October 1 1986 | | | |
Published
| 1987 | | | |
Keywords
| Aspergillus niger, Immobilized Cells, Citric Acid, Semicontinuous, Continuous | | | |
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| | | | | TEI-XML for
| default:Reihe_C/42/ZNC-1987-42c-0408.pdf | | | | Identifier
| ZNC-1987-42c-0408 | | | | Volume
| 42 | |
| 3 | Author
| B. Schöbel, W. Pollmann | Requires cookie* | | | Title
| Isolation and Characterization of a Chlorogenic Acid Esterase from Aspergillus niger | | | | Abstract
| The isolation and characterization o f a specific chlorogenic acid esterase is described. The en zyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means o f ultrafiltration and column-chromatography. The pH-and tempe rature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the en zyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. TTie Ä Tm-value is 0.70 mM chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split chloro genic acid. The isoelectric focusing reveals several isoenzymes o f chlorogenase within a pl-range o f 4 .0 -4 .5 . | | | |
Reference
| Z. Naturforsch. 35c, 209 (1980); received November 20 1979/January 17 1980 | | | |
Published
| 1980 | | | |
Keywords
| Chlorogenic Acid Esterase, Aspergillus niger, High Performance Thin Layer Chromatography | | | |
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| default:Reihe_C/35/ZNC-1980-35c-0209.pdf | | | | Identifier
| ZNC-1980-35c-0209 | | | | Volume
| 35 | |
| 4 | Author
| Abteilung Biochemie, C.H Boehringer Sohn | Requires cookie* | | | Title
| B. Schöbel und W. Pollmann | | | | Abstract
| In addition to our previous paper [1] further characteristics of the chlorogenic acid hydrolase are described. Polyacrylamid gelelectrophoresis revealed only one band for the purified enzyme. Sodium dodecyl-sulfate polyacrylamid gelelectrophoresis showed a molecular weight of 60000, demonstrating four subunits o f the enzyme (total molecular weight 240000). The enzyme is stable in a pH-range of 3 .0 -8 .5 and up to a temperature o f 55 °C. The temperature coefficient Q10 is 1.5, the activation energy EA is 6.0 kcal/mol. The amino acid analysis and substrate specificity data are given in tables. Essential for the enzyme activity is the C=C double bound neighbouring the ester linkage. The enzyme crystallizes in prisms. Weitere Charakterisierung einer Chlorogensäure-Hydrolase aus Aspergillus niger | | | |
Reference
| Z. Naturforsch. 35c, 699—701 (1980); eingegangen am 12. Mai/20. Juni 1980 | | | |
Published
| 1980 | | | |
Keywords
| Chlorogenic Acid Hydrolase, Aspergillus niger, Polyacrylamid Gelelectrophoresis, Amino Acid Analysis, Substrate Specificity | | | |
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| default:Reihe_C/35/ZNC-1980-35c-0699.pdf | | | | Identifier
| ZNC-1980-35c-0699 | | | | Volume
| 35 | |
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