Functionalizing bacterial cell surfaces with a phage protein

Bacterial surface display of metal binding peptides as whole-cell biocatalysts for 4-nitroaniline reduction

Using recombinant microorganisms expressing metal binding peptides as whole-cell biocatalysts for 4-nitroaniline reduction.

Biosynthesis and display of diverse metal nanoparticles by recombinant Escherichia coli

This study used the recombinant E. coli strain expressing the biomolecule, eumelanin, as an agent for the reduction of metal ions.

Development of a broad-host synthetic biology toolbox for Ralstonia eutropha and its application to engineering hydrocarbon biofuel production

Background

The chemoautotrophic bacterium Ralstonia eutropha can utilize H₂/CO₂ for growth under aerobic conditions. While this microbial host has great potential to be engineered to produce desired compounds (beyond polyhydroxybutyrate) directly from CO₂, little work has been done to develop genetic part libraries to enable such endeavors.

Results

We report the development of a toolbox for the metabolic engineering of Ralstonia eutropha H16. We have constructed a set of broad-host-range plasmids bearing a variety of origins of replication, promoters, 5’ mRNA stem-loop structures, and ribosomal binding sites. Specifically, we analyzed the origins of replication pCM62 (IncP), pBBR1, pKT (IncQ), and their variants. We tested the promoters P_BAD, T7, P_xyls/PM, P_lacUV5, and variants thereof for inducible expression. We also evaluated a T7 mRNA stem-loop structure sequence and compared a set of ribosomal binding site (RBS) sequences derived from Escherichia coli, R. eutropha, and a computational RBS design tool. Finally, we employed the toolbox to optimize hydrocarbon production in R. eutropha and demonstrated a 6-fold titer improvement using the appropriate combination of parts.

Conclusion

We constructed and evaluated a versatile synthetic biology toolbox for Ralstonia eutropha metabolic engineering that could apply to other microbial hosts as well.