Enhancement of pullulan production by Aureobasidium pullulans in batch culture using olive oil and sucrose as carbon sources

Citation
F. Youssef et al., Enhancement of pullulan production by Aureobasidium pullulans in batch culture using olive oil and sucrose as carbon sources, APPL BIOC B, 74(1), 1998, pp. 13-30
Citations number
44
Categorie Soggetti
Biotecnology & Applied Microbiology","Biochemistry & Biophysics
Journal title
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
ISSN journal
02732289 → ACNP
Volume
74
Issue
1
Year of publication
1998
Pages
13 - 30
Database
ISI
SICI code
0273-2289(199807)74:1<13:EOPPBA>2.0.ZU;2-I
Abstract
The production of pigment-free pullulan by Aureobasidium pullulans, using o live oil and sucrose as carbon (C) sources, in shake flasks, was investigat ed. Optimum medium composition for pullulan elaboration was 80 g/L sucrose, 25 mL/L olive oil, 5 mL/L Tween-80, 10 g/L glutamic acid, and an initial p H of 5.5. Maximum pullulan concentration (51.5 g/L), productivity (8.6 g/L. d), and yield (80.3%)were achieved under these conditions after 120 h of fe rmentation. The principal advantage of using olive oil and sucrose simultan eously as C sources was the elimination of the inhibitory effect of high su crose concentrations (>60 g/L) on pullulan production by the microorganism, Structural characterization by C-13-NMR, monosaccharide, and methylation a nalyses, and pullulanase digestion, combined with size-exclusion chromatogr aphy, confirmed the identity of pullulan and the homogeneity of the release d polysaccharide in the fermentation broths. There were no significant diff erences in structure between pullulan samples isolated from either olive oi l-supplemented media or olive oil-free media. The molecular size of pullula n from the combined olive oil-sucrose fermentation was slightly lower (1.1 x 10(6)) than that of conventional fermentation with sucrose as a single C source (1.4 x 10(6)). Lowering the initial pH of the medium resulted in inc reased molecular size for the released polymer, but a lower pullulan yield.