<i>In situ</i> spectroscopic analysis of <i>Lactobacillus rhamnosus</i> GG flow on an abiotic surface reveals a role for nutrients in biofilm development YundaElena QuilèsFabienne 2019 <p>In this work, infrared spectroscopy was used to monitor the changes in the biochemical composition of biofilms of the probiotic bacterium <i>Lactobacillus rhamnosus</i> GG (LGG) in three nutritive media (10-fold diluted MRS, AOAC, and mTSB), <i>in situ</i> and under flow conditions. Epifluorescence microscopy was used to observe the shape of LGG cells and their distribution on the surface. Spectroscopic fingerprints recorded as a function of time revealed a medium-dependent content of nucleic acids, phospholipids and polysaccharides in the biofilms. In addition, time-dependent synthesis of lactic acid was observed in MRS/10 and AOAC/10. Polysaccharides were produced to the highest extent in mTSB/10, and the biofilms obtained were the densest in this medium. The rod shape of the cells was preserved in MRS/10, whereas acidic stress induced in AOAC/10 and the nutritional quality of mTSB/10 led to strong morphological changes. These alterations due to the nutritive environment are important to consider in research and use of LGG biofilms.</p>