• Workplace: Paris (75%) and Saint-Malo (25%)
• Date of publication: July 2021
• Scientific supervisors : Pr Soizic Prado (MNHN) & Dr Cécile Le Guillard (CMI Roullier)
• Type of Contract: internship
• Period: 6 months
• Start date of internship: January 2022
Description of the internship topic
Context: this Master 2 internship will be carried out in the context of the SEABIOZ ANR project
involving both academic partners (Roscoff Biological Station, IRISA – Rennes, Natural History
Museum – Paris) and an industrial partner (Agro Innovation International, CMI Roullier – SaintMalo). This 4-year project, started in 2021, aims at providing new insights in the Ascophyllum
nodosum holobiont by evaluating the impact of season, origin, and microbial communities on
biological properties of seaweed extracts. A. nodosum is a common brown alga found along
the coasts of the North Atlantic Ocean. Very little is known so far about the importance of these
symbionts for the seaweed, except that they are believed to protect A. nodosum germlings
from desiccation and improve their robustness to different stresses. A. nodosum also
constitutes a prominent raw material used for many years to produce plant biostimulants and
solutions for the agriculture. Different bioactive molecules such as original polysaccharides
(laminarin, fucoidans, alginates), mannitol, betaines, polyamines, and polyphenolic
compounds, could be involved in these properties but the chemical nature and the
biosynthetical origins of the active molecules remain unknown.
Internship goals: The main objective of the internship will be to investigate the chemistry and
the biological activities of metabolites isolated from microbial strains associated with A.
nodosum. These isolated microbial strains will be cultivated in specific media appropriate for
fungi and bacteria development according to standard protocols developed by MNHN. The
microbial crude extracts will be produced following MNHN protocols to maximize the recovery
of a large number of metabolites and following the AII Roullier requirements which has a
restrictive list of solvent and cost constraints linked to the process upscaling. The analytical
annotation of those fungal and bacterial metabolites will be performed by several mass
spectrometry tools developed by MNHN and AII Roullier including metabolomic and molecular
networking. This approach will be combined with research in natural products and in-house
In vitro bioassays will be carried out at the CMI Roullier to determine the most active crude
extracts for biostimulant properties. Compounds will be thus specifically isolated from active
crude extracts obtained from large-scale cultivation of microorganisms. Pure compounds will
be obtained by different purification techniques (precipitation, ultrafiltration, preparative
chromotagraphy, SPE, …) and then fully characterized by Nuclear Magnetic Resonance (NMR)
and MS spectroscopies.
Student profile: The recruited Master 2 student will have strong experience working at the
microbiology / chemistry of natural substances interface and will have a strong interest in
fundamental research and in applied research.
• Chemistry: experience in chemistry of natural substances: Isolation and
characterization of molecules by MS, NMR Microbiology: knowledge or interest in
microbiology will be an asset.
• Biology: knowledge or interest in plant physiology/biology will be an asset
• Communication skills: english skills, writing of regular reports
Applications should include a detailed CV; at least 1 reference (persons we can contact); a onepage cover letter; notes/results of M1.
Pr. Soizic Prado (email@example.com)
Dr. Cécile Le Guillard (firstname.lastname@example.org)
Application deadline: 04/10/2021.