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| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | Ng Chyan Leong, Assoc. Prof. Dr. | |
| dc.contributor.author | Arief Izzairy Zamani (P78305) | |
| dc.date.accessioned | 2023-10-16T08:36:16Z | - |
| dc.date.available | 2023-10-16T08:36:16Z | - |
| dc.date.issued | 2020 | |
| dc.identifier.other | ukmvital:120016 | |
| dc.identifier.uri | https://ptsldigital.ukm.my/jspui/handle/123456789/515380 | - |
| dc.description | Numerous strategies have been explored to reduce sterilization cost in fermentation technology. Minimal media with vegetable oil as a carbon source at pH 3 had been shown to provide monoseptic cultivation of fungi, subsequently minimize the sterilization process in fungal fermentation. In cells, two different key pathways at central carbon metabolisms, glyoxylate and tricarboxylic acid (TCA) are known to be active upon fatty acids and sugar catabolism respectively. Nonetheless, a systematic comparative interpretation of metabolic changes upon fatty acids or sugars as sole carbon source is still lacking. In addition, the effects of metabolic changes in fungi grow on vegetable oil towards extracellular metabolites secretion is also not known. Hence, this study focused on understanding metabolic changes of selected fungal cultivation, Phialemonium curvatum AW02 (DSM 23903) and Aspergillus oryzae DSM 63303 consequent to palm oil substitute glucose as a sole carbon source. Targeted metabolomics on key pathway at central carbon metabolisms, TCA cycle and glyoxylate cycle were analysed using LC-MS/MS-TripleQ and GC-MS. Untargeted metabolomics were also performed using LC-MS/MS-QTOF followed by multivariate analysis. P. curvatum cultivated in MSM (mineral salt media) with palm oil (MSM-P) or glucose (MSM-G) as a carbon sources provide an insight on the effect of vegetable oil substituted sugar towards global metabolic pathway of fungi. Targeted metabolomics showed recruitment of glyoxylate cycle instead of TCA cycle at central carbon metabolism upon palm oil replaced glucose as carbon source which was supported by activity of key enzyme, isocitrate lyase and isocitrate dehydrogenase. Furthermore, the analysis revealed changes of organic acids concentration between glyoxylate and TCA cycle, ~4- to 8-fold changes for citric acid, succinic acid, malic acid and oxaloacetic acid. Meanwhile, untargeted metabolomics analysis showed that replacement of glucose with palm oil as carbon source significantly perturb the metabolism that highly depend on carbon source such as starch sucrose and glycerolphospholipid metabolisms. Similarly, targeted metabolomics on A. oryzae as a model organism had shown recruitment of glyoxylate and TCA cycle at central carbon metabolism by MSM-P and MSM-G culture respectively. Notable changes in intracellular organic acids concentration were observed on citric acid and cis-aconitic acid, ~2-fold higher in MSM-P compared to MSM-G culture. Nonetheless, the concentration of extracellular citric acid, malic acid and succinic acid were found ~2 to 4-fold lower in MSM-P compared to MSM-G culture. Meanwhile, untargeted metabolomics identified metabolisms that significantly perturbed by the replacement of glucose with palm oil as carbon source including kojic acid and oxylipin biosynthesis. In addition, high concentration of penicillic acid that detected in extracellular of MSM-P culture might contribute to the suppression of bacterial contamination. Correlation dynamic had been observed between intracellular and extracellular organic acid from both cultures, suggesting that the organic acids transportation in A. oryae were following metabolic overflow concept and active efflux. A hundred litre scale cultivation of A.oryzae highlighted the robustness of MSM-P to provide monoseptic cultivation under minimal steriliation condition without bacterial contamination at large scale. Overall, this study provided details changes between glyoxylate and TCA cycle at central carbon metabolism and illustrated the significantly perturbed metabolism and physiological differences when vegetable oil replace sugar as carbon source in fungal fermentation. Catabolism of vegetable oil in fungi was found able to promote accumulation of lipids or secretion of high concentration extracellular organic acids, which highly depend on fungal species, Furthermore, A. oryzae was found to secrete metabolites such as penicillic acid to suppress growth of bacterial contaminant and to compete for nutrient. This study suggested that palm oil is a potential alternative carbon source for minimal sterilization fermentation process. Based on the findings from this study, fungal strains that can grow in the MSM-P system can be further optimized to economically replace current fermentation process and expand future metabolic engineering strategies.,Ph.D | |
| dc.language.iso | eng | |
| dc.publisher | UKM, Bangi | |
| dc.relation | Institute of Systems Biology / Institut Biologi Sistem (INBIOSIS) | |
| dc.rights | UKM | |
| dc.subject | Fermentation -- Technological innovations | |
| dc.subject | Fermentation | |
| dc.subject | Universiti Kebangsaan Malaysia -- Dissertations | |
| dc.subject | Dissertations, Academic -- Malaysia | |
| dc.title | Metabolic and physiology studies of selected fungi grown on minimal media with palm oil as sole carbon source | |
| dc.type | Theses | |
| dc.format.pages | 166 | |
| dc.identifier.barcode | 004745(2020) | |
| Appears in Collections: | Institute of Systems Biology / Institut Biologi Sistem (INBIOSIS) | |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| ukmvital_120016+SOURCE1+SOURCE1.0.PDF Restricted Access | 3.45 MB | Adobe PDF |  View/Open |
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