| Autor: |
Hatzinikolaou, D. G., Kourentzi, E., Stamatis, H., Christakopoulos, P., Kolisis, F. N., Kekos, D., Macris, B. J. |
| Jazyk: |
angličtina |
| Rok vydání: |
1999 |
| Popis: |
Cell-bound lipase activity (10 pNPL units/g dry cell weight) was released when the yeast Rhodotorula glutinis was cultured in a 7-l stirred tank fermentor using palm-oil as the sole carbon source. The enzyme showed relative specificity towards medium chain organic acids since the apparent K(m) values for pNPB (p-NitroPhenyl-Butyrate) and pNPL (p-NitroPhenyl-Laurate) were equal to 2.7 and 0.7 mM, respectively. In addition, 80% of this activity could be detected on the surface of the cells. The cell-bound nature of the enzyme increased its thermal stability showing half-life times of 200 and 60 min at 50 and 60 degrees C, respectively, as well as good stability in organic solvents. Freeze-dried cell preparations were successfully used to catalyze the synthesis of fatty acid esters of butanol and heptanol in nearly anhydrous organic solvents. A conversion of 60-62% was obtained upon esterification of palmitic or oleic acid with butanol, within 96 h. The enzyme preparation was used in four consecutive batch reactions with only 10% loss of activity. J Biosci Bioeng |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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