Sakinah Ibrahim (2018) Co-cultivation of locally isolated yeast rhodotorula sp. and microalgae chaetoceros muelleri for enhancement of lipid production. Masters thesis, Universiti Malaysia Sabah.
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Abstract
Microbial-producing oils such as yeast and microalgae have attracted researchers' interests as an alternative to the conventional biodiesel feedstocks. The simplicity of operation due to the oleaginous microorganisms' rapid growth and similar fatty acid profiles with the vegetable oils making them versatile microbes with valuable applications. The co-cultivation of lipid-producing yeast and microalgae has been recognized having a synergistic activity that is beneficial to increase biomass and lipid production compared to monoculture. In this study, the cultivation conditions of yeast Rhodotorula sp. and microalgae Chaetoceros muelleri as well as co-culture were optimized to enhance lipid production. The yeast and microalgae were obtained from Mamut Copper Mine and Kata Kinabalu Wetland, respectively. The studied growth conditions include the initial pH of media, light intensity, co-culture inoculum ratio and harvesting time. The growth of the culture was determined using UV spectrophotometer while the lipid production was analyzed using methanol: chloroform: water (1:1:1) lipid extraction method. The detection of gene responsible in lipid production known as malic enzyme was also employed. The findings of the study revealed that the optimal pH for Rhodotorula sp., C. mue/leri and co-culture were 7 .0, 7.5, and 6.0 respectively. The light intensity at 15,000 lux and inoculum ratio of 1: 3 (yeast: microalgae) were found providing the best conditions for the co-cultures. The optimum harvesting time for microalgae and co-culture was 10 days, while the yeast could sustain up to 30 days for greater lipid production. In comparison with monocultures, the co-culture had successfully increased the biomass productivity from 0.01 to 0.16 g/1/day and lipid productivity from 1.1 to 2.4 g/I/day. These findings, which supported by the detection of malic enzyme gene in yeast and co-culture cultivations, indicated that both are potential lipid producers. Co-culturing of yeast and microalgae enhanced the lipid production that is promising for a sustainable and industrially viable microbial-oil biofuel production.
| Item Type: | Thesis (Masters) |
|---|---|
| Keyword: | Microbial oil production, Oleaginous microorganisms, Lipid-producing yeast, Microalgae, Rhodotorula sp. |
| Subjects: | T Technology > TP Chemical technology > TP1-1185 Chemical technology > TP248.13-248.65 Biotechnology |
| Department: | INSTITUTE > Biotechnology Research Institute (BRI) |
| Depositing User: | DG MASNIAH AHMAD - |
| Date Deposited: | 13 Jun 2025 15:00 |
| Last Modified: | 13 Jun 2025 15:00 |
| URI: | https://eprints.ums.edu.my/id/eprint/44049 |
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