A few words

When AFM microscopy improves microalgae harvesting

Cécile Formosa-Dague, Pascal Guiraud
Unicellular microalgae have the ability, under certain cultivation conditions, to accumulate large quantities of lipids that can be used to produce biofuels. Our group in collaboration with LAAS-CNRS have studied the flocculation of microalgae, which consists in aggregating the cells with a flocculating agent in order to separate them more easily. This is a common harvesting process, but its mechanisms were still poorly understood. To scrutinize the mechanisms, atomic force microscopy (AFM) was implemented on individual cells to quantify interactions.

Single-molecule force spectroscopy of adhesive biomolecules

Mickaël Castelain
Using a laser beam, it is possible to manipulate a protein on the surface of a living bacterium and to stretch it to its breaking point. These experiments provide valuable information on the dynamic structure of the macromolecule, such as its elasticity, but also its conformation when subjected to a force of the order of a picoNewton (1 millionth of a Newton). Our group, in collaboration with the MICALIS Institute (INRAE, Jouy-en-Josas), have studied the structure of the pilus (plural: pili) - a protein secreted on the surface of a bacterium and involved in adhesion to a surface - produced by Lactococcus lactis. This bacterium, found mainly in the dairy environment, has the capacity to form communities called biofilms. The formation of biofilms encountered in the food industry is a real societal issue for food safety. To answer this question, an optical tweezers instrumentation has been developed at LISBP and allows to manipulate the micron (1 millionth of a meter) in order to measure minute forces.

Ongoing projects 


thèse d’Ali Hamieh, collaboration LGC & Arkema