EncaBcillus – It’s a trap!

Synthetic biology wants to go beyond the pure biological by integrating concepts from chemistry or physics into the living world. At this interphase, our project wants to introduce Peptidosomes as a new fundamental approach for generating and applying encapsulated bacteria. These spheres possess advantageous properties like stability in different media and a mesh-like structure that allows for the selective exchange of compounds via diffusion. Therefore, we are able to benefit from the entrapped cells’ abilities, while ensuring that they are not released into their surroundings. Using the powerful genetics of Bacillus subtilis and its secretory capabilities we demonstrate communication and cooperation between separately encapsulated bacterial populations as well as the environment. Peptidosomes can be further enhanced by incorporating magnetic or biological beads – which can be functionalized with proteins – into their peptide-based shell. With this unique setup, we provide a whole new universe of applications to the iGEM community.

Bacillus subtilis – The Gram-positive model organism

B. subtilis is the best-studied Gram-positive microorganisms, and a model bacterium studying bacterial differentiation (e.g. endospore formation) and phenotypic heterogeneity.[1][2] Its ability to become naturally competent makes B. subtilis an organism with easily tractable genetics.[3] The GRAS (generally recognized as safe) status and secretory capacity made B. subtilis a preferred host of choice for big scale production of secreted proteins, such as lipases, proteases and amylases, highlighting the industrial relevance of this bacterium. [5]

In addition, the iGEM Team LMU-Munich 2012 has constructed the Bacillus BioBrickBox, which contains several well evaluated integrative vectors and other parts for the use in B. subtilis, thus providing a powerful toolbox to engineer B. subtilis.[6]

References

[1]	Lopez, D., Vlamakis, H. & Kolter, R. (2009) Generation of multiple cell types in Bacillus subtilis: from soil bacterium to super-secreting cell factory. FEMS Microbiol. Rev., 33, 152–163.
[2]	Lopez, D. & Kolter, R. (2010) Extracellular signals that define distinct and coexisting cell fates in Bacillus subtilis. FEMS Microbiol. Rev. 34, 134–149
[3]	Kaufenstein, M., van der Laan, M. & Graumann, P. L. (2011) The three-layered DNA uptake machinery at the cell pole in competent Bacillus subtilis cells is a stable complex. J. Bacteriol. 193, 1633–1642.
[4]	Fu L. L., Xu Z. R., Li W. F., Shuai J. B., Lu P. and Hu C. X. (2006) Protein secretion pathways in Bacillus subtilis: implication for optimization of heterologous protein secretion. Biotechnology advances 25, 1 (1-12).
[5]	Harwood, C. R. (1992) Bacillus subtilis and its relatives: molecular biological and industrial workhorses. Trends Biotechnol. 10, 247–256
[6]	Radeck, J., Kraft, K., Bartels, J., Cikovic, T., Dürr, F., Emenegger, J., Kelterborn, S., Sauer, C., Fritz, G., Gebhard, S., and Mascher, T. (2013) The Bacillus BioBrick Box: generation and evaluation of essential genetic building blocks for standardized work with Bacillus subtilis. J Biol Eng 7, 29.