STUDIES ON THE BIOCONVERSION OF GLYCYRRHIZIN
HALA ABDEL SALAM AMIN;
Abstract
1. Screening of microorganisms (13 bacteria, 2 yeasts and 23 fungi) for • production of GA from GL was carried out. A. niger NRRL 595 produced the highest yielof GA.
2. The bioconversion of GL with A. niger NRRL 595 for 96 h, followed by isolation of the transformation products by preparative TLC technique and purification of the isolated products on Sephadex LH-
20 led to the isolation of two conversion products, namely: GA and 3-
oxo-GA.
3. Confirmation of the identity of these products was established by comparison of their Rr values, m.p., and IR, UV, MS and NMR spectra, with those of authentic samples.
4. Bioconversion of GL by A. niger NRRL 595 using eight different media was investigated. The highest GL bioconversion efficiency (25.19 %) was achieved with medium I composed of (g %) GL 1, glucose 1 and CSL 0.8 (basal medium).
5. Different levels of glucose, CSL and GL were tested and an optimized medium containing 0.5 g % glucose, 0.8 g % CSL and 1.75 g% GL afforded the best bioconversion ofGL (61.45 %) and accompanied by the highest yield ofGA ( 45.9%).
6. The biotransformation process was influenced by the pH value of the fermentation medium and the highest bioconversion estimates were maintained at initial pH of6.5.
7. Maximum GA output was obtained at 30°C. However, the optimum temperature for 3-oxo-GA production was 35°C.
2. The bioconversion of GL with A. niger NRRL 595 for 96 h, followed by isolation of the transformation products by preparative TLC technique and purification of the isolated products on Sephadex LH-
20 led to the isolation of two conversion products, namely: GA and 3-
oxo-GA.
3. Confirmation of the identity of these products was established by comparison of their Rr values, m.p., and IR, UV, MS and NMR spectra, with those of authentic samples.
4. Bioconversion of GL by A. niger NRRL 595 using eight different media was investigated. The highest GL bioconversion efficiency (25.19 %) was achieved with medium I composed of (g %) GL 1, glucose 1 and CSL 0.8 (basal medium).
5. Different levels of glucose, CSL and GL were tested and an optimized medium containing 0.5 g % glucose, 0.8 g % CSL and 1.75 g% GL afforded the best bioconversion ofGL (61.45 %) and accompanied by the highest yield ofGA ( 45.9%).
6. The biotransformation process was influenced by the pH value of the fermentation medium and the highest bioconversion estimates were maintained at initial pH of6.5.
7. Maximum GA output was obtained at 30°C. However, the optimum temperature for 3-oxo-GA production was 35°C.
Other data
| Title | STUDIES ON THE BIOCONVERSION OF GLYCYRRHIZIN | Other Titles | دراسات على التحولات الميكروبيولوجية للجليسرهزين | Authors | HALA ABDEL SALAM AMIN | Issue Date | 2005 |
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