|Asst Prof Jiang Rongrong|
Division of Chemical and Biomolecular Engineering
School of Chemical and Biomedical Engineering
College of Engineering
Phone: (+65)6514 1055
- PhD Georgia Institute of Technology 2006
- BS(Biochemical Eng) Nanjing Univ. of Chemical Technology 2000
|Dr. Jiang joined School of Chemical & Biomedical Engineering, NTU in 2006 after she received her Ph.D. degree from Georgia Institute of Technology. Dr. Jiang is a member of American Chemical Society and American Institute of Chemical Engineers.|
|i) Nanoscale Biocatalysis|
Nanotechnology-inspired biocatalyst systems have attracted a lot of attention in enzyme immobilization recently. Theoretically, nanomaterials are ideal supporting materials because they can provide the upper limits on enzyme-efficiency-determining factors such as surface area/volume ratio, enzyme loading capacity and mass transfer resistance. However, common immobilization methods (adsorption, covalent binding, and entrapment) have limited the applicability of these biocatalysts owing to enzyme leaching, 3D structure loss, and strong diffusion resistance. Expensive enzyme purification step is also required for these methods before immobilization. Our group has developed an efficient immobilization method based on the specific interaction between His-tagged NADH oxidase and functionalized nanomaterials, such as single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and carbon nanospheres, without requiring enzyme purification. The resulting conjugates demonstrated excellent activity retention and stability improvement. We have not only applied this immobilization approach on individual enzymes, but also on multi-enzymatic system such as in situ cofactor regeneration system.
ii) Transcriptional Engineering
Breeding industrial microorganisms with desired properties has been achieved by classical strain engineering methods in the past, such as spontaneous adaptation and mutagenesis with UV/chemical mutagens, which are simple but inherently time-consuming and labor-intensive. Metabolic engineering tool has also been employed to pursue improvement in fermentation performance of microorganisms since its advent, but it requires prior strain genetics and physiology knowledge. In recent years, transcriptional engineering have started to attract attention in strain engineering, which addresses the limitations of traditional methods. Our group is focusing on engineering global transcription factor to improve stain performance during fermentation. We brought directed evolution technique from protein engineering to strain engineering and used it to introduce mutations to a transcription regulatory protein. Small changes to this transcription regulatory protein can lead to big changes in transcription regulation, and perturbations on transcription may induce genetic diversities, which can lead to a variant pool with different phenotypes accordingly. Mutant strains with enhanced performance were selected by high throughput screening. Compared to classical strain engineering methods, this approach can greatly shorten the selection period from weeks/months to 3 − 5 days.
|Research Grant |
- Academic Research Fund Tier 1 (2012-) [by Ministry of Education (MOE)]
- Academic Research Fund Tier 2 (2013-) [by MOE]
- NRF Competitive Research Program (2010-) [by National Research Foundation (NRF)]
|Current Projects |
- Biocatalysts with Novel Alkyl Hydroperoxide Reductase
- Directed Evolution of Transcription Factor cAMP Receptor Protein (CRP) for Improved Cell Performance during Biofuel Production
- Engineering biology for valuable fuels- Increasing acetyl-CoA level
- Improve Clostridium acetobutylicum ATCC 824 1-butanol tolerance and productivity
- Novel Cofactor-Regenerating Enzyme Applied In Enzyme Membrane Reactor
- Novel Cofactor-Regenerating Enzyme Applied In Enzyme Membrane Reactor (SEP)
- Souvik, B.; Jiang, R.*. (2012). Enhancing E. coli Tolerance towards Oxidative Stress via Engineering its Global Regulator cAMP Receptor Protein (CRP). PLoS ONE, 7(12), e51179.
- Zhang, H.; Chong, H.; Ching, C.; Jiang, R.*. (2012). Random mutagenesis of global transcription factor cAMP receptor protein for improved osmotolerance. Biotechnology and Bioengineering, 109(5), 1165-1172.
- Wang, Liang; Wei, Li; Chen, Yuan; Jiang, Rongrong. (2010). Specific and reversible immobilization of NADH oxidase on functionalized single-walled carbon nanotubes. Journal of Biotechnology, 150, 57-63.
- Zhang, Hongfang; Lountos, George; Ching, Chi-Bun; Jiang, Rongrong. (2010). Engineering of glycerol dehydrogenase for improved activity towards 1,3-butanediol. Applied Microbiology and Biotechnology, 88(1), 117-124.