Microalgae produce molecules of interest with promising outlets, particularly for animal feed, cosmetics and pharmaceuticals. The process used to produce microalgae in the form of mobile biofilm (patented by 3 of the partners), and exploited by the inalve start-up, offers a marked gain in productivity and stability. Tests carried out since 2016 over several months by inalve have shown the very high resilience of microalgae biofilms, that is probably due to the excretion of allelopathic molecules with high antimicrobial activity. The first objective of the Photobiofilm Explorer project is to understand the reasons for this resilience by analyzing the nature and activity of the molecules produced. The second is to characterize and control some of these activities in order to domesticate their potential for human and animal health in a context of increasing antibiotic resistance.