Invité N. Terrapon: Nicolas Vita, LBC, Marseille -« Flavolases project concept and progresses: Hijacking the Flavobacterium type IX secretion machinery for efficient cellulolytic activity (PEPR B-BEST AAPG 2024)

Résumé

While harnessing microbial cellulolytic capabilities for biotechnological design and conversion of cellulose into desired compounds holds great potential, innovations are needed to realize its economic potential. The FLAVOLASES project aims to leverage Flavobacteria and their unique secretion capabilities to generate highly cellulolytic bacteria capable of massive secretion of both artificial cellulosomes and free CAZymes.

Flavobacteria (phylum Bacteroidota) use a highly efficient secretion apparatus called the type IX secretion system (T9SS), a versatile nanomachine recently discovered that secretes dozens of different enzymes with various size (up to 670 kDa) and activities, notably CAZymes. It has been shown that upon fusion with a specific and small C-Terminal Domain, enzymes different from the natural substrates can be abundantly and specifically released in the medium by the T9SS.

In the FLAVOLASES project, we seek to engineer Flavobacterium johnsoniae into a novel, efficient cellulolytic biocatalyst by exploiting the T9SS to export minicellulosomes and free cellulases, and to improve the secretion of the newly integrated cellulolytic system phenotype using adaptive laboratory evolution (ALE).

Altogether, the project aims to shape an efficient cellulolytic system necessary to plant biomass-based biorefineries design. Furthermore, it will also provide significant information on the T9SS mechanism of action and how to use and foster its efficiency to secrete desired proteins such as cellulolytic enzymes cocktails or minicellulosomes useful to treat plant biomass in industrial processes.