Lab-on-a-chip reveals unforeseen microconfined motility of soil bacteria

V.I. MARCONI

Congreso; III Brazil-Argentina Microfluidics Congress / VI Congreso de Microfluídica Argentina; 2022

Soil bacteria populations are used since several decades ago as biofertilizers. Even though they are well-known and extensively used due to low-cost, such biotechnology is still far from being efficient and multiple challenges are opened for basic research. Our microbiological system of study is the textitBradyrhizobium diazoefficiens, a bacteria with two flagellar systems used as biofertilizer of soybean crops for 96% of farmers in Argentina. One biological opened question is the biflagellum system function developed by this specie and not developed in general in Bradyrhizobium. It may be an adaptive trade-off between energetic costs and ecological benefits among different species. Our interdisciplinary project study bacteria diffusion in porous media, numerically and experimentally, imitating the complex and structured soil into microfluidic devices. Such soil on a chip offers as an original and proper visualization tool, easy to manipulate in a laboratory and ideal to understand and control the transport properties of the system for further realistic applications. We have reported their strategies to swim for first time [textitQuelas et. al., Sci.Rep. 2016]. Now we model and simulate its confined dynamics with such realistic parameters an even with much better measured and analyzed data of motility. Even more, a broad spectrum of micro-confinement environments were simulated and designed, contributing to microfabricate different geometries of soil grains connected by micro-channels. Our results versus the channel width contribute to understand soil bacteria diffusion properties for different flagellar systems and different degree of confinement. Those contributions thanks to use new tools of micro-visualization of soil bacteria, hope to be useful for further development of a sustainable agronomy.Acknowledgments: ANID–Fondecyt 3190637, ANID–Millennium Science Initiative Program – NCN19- 170 (Chile), SeCyT-UNC and PICT-2020- SERIEA-02931 (Argentina).