Bacteria quorum sensing in silica matrices

Serratia marcescens bacteria were encapsulated in silica gels containing glycerol. In agreement with previous studies on Escherichia coli, entrapped cells showed a ca. 50% viability rate after one month. Nutrients were provided to the bacteria, allowing the production of prodigiosin, a red pigment exhibiting some promising therapeutic properties. Addition of quorum sensing'' molecules involved in intercellular communication leads to an enhanced prodigiosin production after four subsequent recyclings of the bacteria-containing gels over one month. Moreover, at the end of this period, nearly 100% of the initial cell population remain viable within the gels. These results suggest that, in the presence of quorum sensing'' molecules, S. marcescens bacteria can enter a stationary state where their metabolism is modified, enhancing their resistance to the stresses induced by encapsulation.