There is an urgent need to identify new drugs to deal with major health challenges such as the control of serious pathogens which have gained resistance against current antibiotics. Microalgae constitute a source of eukaryotic organisms to be explored for the production of more efficient and biologically active compounds. They have gained interest lately for innovative solutions in various applications and they are now recognized as a valuable and sustainable source for food and feed. They are classically cultivated in photobioreactors or raceways as liquid suspension. To further enhance productivity at reduced environmental cost an innovative approach has been developed and patented by three of the project partners, consisting in growing microalgae in a biofilm on a moving conveyer belt. The Inalve startup was launched to exploit this technology and won several prices. A biofilm is an assemblage of microorganisms associated to a surface and embedded in a secreted matrix of extracellular polymeric substances. Surprisingly, most of the tested species by Inalve are able to form biofilms extremely resistant to biological contamination. Even when adding glucose, the cellular ratio bacteria/microalgae in the biofilm remains strongly controlled to a very low value suggesting that some compounds released by microalgae (and/or associated bacteria within the biofilm) are able to inhibit invaders and play a significant role in the biofilm resilience and stability. These compounds are known to reach concentrations high enough to also impact planktonic microorganisms in the neighbourhood of the biofilm. A vast range of allelopathic substances have been identified as active over other microorganisms. They possess unique bioactivities now exploited in animal and human health.
The first objective of the project is to explore the activity of the produced molecules explaining the resistance of the biofilm. The second objective is to identify, characterize and produce novel biocompounds with benefits for human or animal health. Our main target is antibiotics, but other activities will be tested, especially antiviral activities. The seek for such innovative natural molecules will have a deep impact in term of valorization including protection of fishes and shellfishes in aquaculture (main Inalve market) and in pharmaceutics through the discovery of novel antibiotics and antiviral compounds.
Photobiofilm Explorer is organized as six technical workpackages. Biofilms from four marine microalgal species with strong potential to produce allelochemical compounds will be grown and studied along with their bacterial phycosphere. WP1 focuses on the bioactive compounds production under nitrogen stress, while WP2 will consider the role of the microalgae-associated bacteria. Microscopic tools for assessing biofilm 3D structure and its relation to allelopathic compounds production will be developed in WP3. Measurement of the antimicrobial activity, the associated allelochemical concentration and chemical identification will be carried out in WP4 with a broad screening of pathogenic bacteria, harmful for animal and human health, and viruses. The conditions leading to the highest allelochemical production, once optimized using the simulation tools of WP5 will be implemented in the Inalve biofilm pilot processes in WP6.
The consortium gathers excellent teams recognized for their expertise in algae-bacteria interaction (MARBEC), physiological study of microalgae (LOV), 3D multispecific biofilm characterization (INRAE, CS), advanced mathematical modelling (INRIA, CS), bioprocess engineering (CS), and innovative industrial biofilm cultivation (Inalve). The actors have a long track record in efficient and successful collaborations. The project is coordinated by O. Bernard, Senior Researcher, PhD in Biological oceanography, worldwide-acknowledged specialist of microalgae and bioprocess optimisation, with a long track record of successful project coordination.
Monsieur Olivier BERNARD (Centre de Recherche Inria Sophia Antipolis - Méditerranée)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
LGPM LABORATOIRE DE GENIE DES PROCEDES ET MATERIAUX
LOV Laboratoire d'océanographie de Villefranche
Inria Centre de Recherche Inria Sophia Antipolis - Méditerranée
MARBEC Centre pour la biodiversité marine, l'exploitation et la conservation
MICALIS MICrobiologie de l'ALImentation au service de la Santé
Help of the ANR 604,870 euros
Beginning and duration of the scientific project: - 36 Months