| dc.contributor.advisor | Feußner, Ivo Prof. Dr. | |
| dc.contributor.author | Yu, Dan | |
| dc.date.accessioned | 2017-12-06T09:51:08Z | |
| dc.date.available | 2017-12-06T09:51:08Z | |
| dc.date.issued | 2017-12-06 | |
| dc.identifier.uri | http://hdl.handle.net/11858/00-1735-0000-0023-3F9F-3 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-6622 | |
| dc.language.iso | eng | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 570 | de |
| dc.title | Production of wax esters in Camelina sativa | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Gatz, Christiane Prof. Dr. | |
| dc.date.examination | 2016-12-14 | |
| dc.description.abstracteng | Wax esters are the esters of primary long-chain fatty alcohols and long-chain fatty acids in various combinations, including different chain length and a variety of desaturation degrees. Wax esters cover a wide range of chemical and physical properties, therefore are interesting for many industrial applications. 18:1/18:1 is the most favorable wax ester species for the lubrication purpose. To establish a heterologous pathway for wax ester biosynthesis in plants, only two enzymes are necessary, a FAR and a WS. In previous studies, the introduction of FARs and WSs form different organisms into the seeds of C. sativa resulted in the accumulation of wax esters, but the yields of wax esters as well as the levels of 18:1/18:1 were still low for industrial applications. Attempts of producing higher yields of wax esters, and especially promoting the formation of 18:1/18:1 in seeds of C. sativa for industrial purpose were conducted, and several approaches were tried in the present study.
In opposition to the previous studies that always focus on the eukaryotic WSs, the abilities of a bifunctional WS/DGAT enzyme from A. baylyi ADP1 and several WSs from M. aquaeolei VT8 were tested in the present study. An enzyme from M. aquaeolei VT8 was identified as a novel WS by both in vivo and in vitro assays. Co-expression of bacterial-type WSs with MaFAR in seeds of A. thaliana did not resulted in big amounts of wax esters. However, the compositions of the wax esters produced by the bacterial-type WSs was more favorable for lubrication. The optimization of a bacterial-type WS led to increased levels of wax esters, but the resulting yields were still lower than in the MaFAR/ScWS lines that were obtained in a previous experiment. The co-localization of MaFAR together with ScWS to the ER was not able to increase the yields of wax esters in seeds of A. thaliana, while led to obvious alternations in the compositions of wax esters. This work provides better insights into the enzymatic characteristics and the substrate specificities of several wax ester production enzymes.
The attempt to down-regulate CsDGAT1 neither block the last step of TAG biosynthesis nor further promote the biosynthesis of wax esters in seeds of C. sativa. Whereas, co-expression of amiDGAT1 with MaFAR and ScWS unexpectedly altered the compositions of TAGs and wax esters in seeds of C. sativa. Expression of MaFAR with ScWS in a high oleic acid C. sativa background by crossing the MaFAR/ScWS lines with an Atfad3/Csfad2/Csfae1 line did not affect the yields of wax esters, whilst led to the accumulation of 18:1/18:1 up to 40 mol% of all wax ester molecular species. This study suggested the importance of acy-CoA pool for tailoring the compositions of wax esters, and also showed that the biosynthesis of valuable chemical stocks at a big amount in plant seeds is still a challenge. | de |
| dc.contributor.coReferee | Polle, Andrea Prof. Dr. | |
| dc.subject.eng | wax esters | de |
| dc.subject.eng | Camelina sativa | de |
| dc.subject.eng | wax synthases | de |
| dc.subject.eng | Fatty acid reductase | de |
| dc.subject.eng | lipid metabolic engineering | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-11858/00-1735-0000-0023-3F9F-3-7 | |
| dc.affiliation.institute | Fakultät für Forstwissenschaften und Waldökologie | de |
| dc.subject.gokfull | Forstwirtschaft (PPN621305413) | de |
| dc.identifier.ppn | 1007471794 | |