碩士 / 元智大學 / 生物科技與工程研究所 / 100 / Energy depletion and global warming are two major problems in the world. To deal with these problems, sustainable bioenergy offers the potential to provide secure and low carbon energy. The fast growing microalgae don’t compete land resource and therefore draw public attention. However, microalgal culture is easy to be influenced by environmental factors, such as temperature, light and salt concentration, so the yield of algal starch, oil or the whole biomss is not stable. In this study, we used transgenic approach to increase the tolerance of microalgae under the stress condition. We further evaluate the possible application of the transgenic microalgae in photo microbial fuel cell (PMFC) and biorefinery.
Ferredoxins (Fd) are final electron carrier proteins in plant photosynthetic pathway. Under environmental stresses, reactive oxygen species (ROS) that have the potential to cause membrane and protein damage are produced. We hypothesize that reduction of ROS is able to avoid cells subjected to injury. Fd proteins accept electrons from photosystem, and donate them to other downstream proteins. Increasing the expression of Fd will increase total reduced form of Fd to help cell overcome the oxidative stress from ROS. In this study, Chlamydomonas reinhardtii, a model organism is used to increase gene expression of its Fds by genetic engineering approach. Two Fds are engineered to enhance their expression: 1. PetF, the endogenous maximum form of Fds and 2. Fdx5, the stress induced form of Fds. Our goal is to establish transgenic algal cell lines containing strong ability to endure adversity for bioenergy application.
Under normal growth condition, transgenic Chlamydomonas cell lines overexpressing Fd produced about1.5-fold of starch and oil than wild-type. In addition, transgenic algae have at least 2 folds more power density than the wild-type strain in PMFC. Under 200 mM NaCl, Fd overexpression cell lines have 80% survival rate; whereas wild-type remain less than 30% survival rate, indicating that transgenic cell lines are more resistant under salt stress. When treatment of 42°C for 30 minutes was applied, the survival rate of wild type is dropped to 48%; whereas transgenic algae remain more than 90% of survival rate.
| Identifer | oai:union.ndltd.org:TW/100YZU05111112 |
| Creators | Ji-Yu Lin, 林紀宇 |
| Contributors | 黃麗芬 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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