2022 Fiscal Year Annual Research Report
Production of Useful Chemicals from Glycerol by Metabolic Modification of Microorganisms
| Project/Area Number |
22J20479
|
|---|
| Allocation Type | Single-year Grants |
|---|
| Research Institution | University of Tsukuba |
|---|
Principal Investigator |
ALAWI ASEEL 筑波大学, 理工情報生命学術院, 特別研究員(DC1)
|
|---|
| Project Period (FY) |
2022-04-22 – 2025-03-31
|
| Keywords | glycerol / 1,3-propanediol / 3-hydroxypropionic acid / Citrobacter braakii |
|---|
| Outline of Annual Research Achievements |
To produce 3-hydroxypropionic acid (3-HP) from glycerol we used Citrobacter braakii strain TB-96-dLF, which was previously modified to produce high 1,3-propandiol (1,3-PD) concentration from glycerol. First, we disrupted propanediol dehydrogenase (pdh) gene to block 1,3-PD production (TB-96-dLFP). Since TB-96-dLFP may accumulate the toxic 3-hydroxypropionaldehyde (3-HPA) intermediate, we fermented it under aerobic condition as to produce 3-HP from glycerol via 3-HPA. However, no production of 3-HP was observed. This may be due to the instability of the first enzyme of glycerol metabolism which is glycerol dehydratase (Gdh) under aerobic conditions.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Even though we expected that the deletion of propanediol dehydrogenase (pdh) gene in strain TB-96-dLFP will result in 3-hydroxypropionic acid (3-HP) production from glycerol via 3-hydroxypropionaldehyde (3-HPA), fermentation under aerobic conditions showed low glycerol consumption and 3-HP production was not observed. This was explained by the instability of glycerol dehydratase (Gdh)the first enzyme involved in glycerol metabolism. Thus, further enhancement of gdh is necessary under aerobic conditions.
|
| Strategy for Future Research Activity |
Aiming at the enhancement of glycerol metabolism under aerobic conditions, overexpression of glycerol dehydratase (gdh) gene is needed. Thus, we plan to screen suitable over expression vectors that can be transformed and replicated in TB-96-dLF. Next, genetic modification of antibiotic resistance cassette will be conducted for easier selection. Last, cloning of related genes and construction of insert will be conducted.
|
