Effect of physical and chemical conditions on the production of colominic acid by Escherichia coli in a defined medium
| Autor: | Ana I. Ortiz, Angel Reglero, José M. Luengo, Leandro B. Rodríguez-Aparicio |
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| Rok vydání: | 1988 |
| Předmět: |
Chromatography
biology Kinetics chemistry.chemical_element General Medicine biology.organism_classification medicine.disease_cause Applied Microbiology and Biotechnology Nitrogen Sialic acid chemistry.chemical_compound Chemically defined medium chemistry Biochemistry Biosynthesis medicine Aeration Escherichia coli Bacteria Biotechnology |
| Zdroj: | Applied Microbiology and Biotechnology. 27:474-483 |
| ISSN: | 1432-0614 0175-7598 |
| DOI: | 10.1007/bf00451616 |
| Popis: | A chemically defined medium capable of supporting the growth of Escherichia coli K-235 and optimal for colominic acid (poly-N-acetylneuraminic acid) production has been developed. When the culture was incubated at 37° C for 72 h in 250-ml shake flasks at 250 rpm (in a Gallenkamp incubator IRN-200; orbital diameter 32 mm), the highest polymer level (about 1,350 μg ml-1) was obtained in a minimal medium in which D-xylose and L-proline were the only carbon and nitrogen sources. The optimal pH range for its production (7.6–8.0) was maintained by buffering the medium with 80 mM KH2PO4/Na2HPO4 and the best aeration ratio was 4:1 (volume flask:volume medium). In these conditions high colominic acid biosynthetic activity was detected in the early logarithmic phase and was maximal in 19-h-old cells (A540 nm=4.0). However, the release of polysialic acid into the broth started when growth stopped, showing kinetics typical of a secondary metabolite. The biosynthesis of this polymer was seen to be strictly temperature regulated. |
| Databáze: | OpenAIRE |
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