Biology and Biotechnology
Using a multidisciplinary approach, we investigate the metabolism and stress responses of cyanobacteria (the most abundant photosynthetic organisms) with the prospect of using them for the sustainable production of biofuels, and biodetection of metal pollutants. These two objectives are intrinsically related as the metabolism uses a wealth of metallo-enzymes.
Cyanobacteria, the only known prokaryotes that perform oxygen-evolving photosynthesis, are environmentally crucial organisms, which logically receive a strong attention in basic and applied researches. Cyanobacteria, which are the most abundant photosynthetic organisms on Earth, use solar energy, water, CO2 and mineral salts to produce a large part of the oxygen and biomass for the food chain.
In nature, cyanobacteria are inevitably challenged by toxic reactive oxygen species generated by their metal-rich photosynthesis under intense illumination, i.e. when the production of photosynthetic electrons exceeds what needed for the assimilation of inorganic substrates. Furthermore, in requiring high amounts of various metals (iron, zinc, Cu, Mn etc) for growth, cyanobacteria are also frequently affected by changes in metal availability and/or the presence of heavy metals, which are increasingly spread in environment through human industries and agriculture, and constitute persistent pollutants because they cannot be degraded. Consequently, it is important to analyze the protection against oxidative and metal stresses in cyanobacteria because they constitute the first biological barrier against the entry of toxics into the food chain, and these crucial organisms have developed most of the stress-tolerance mechanisms, a large number of which have been evolutionary conserved.
SEM images of the unicellular cyanobacterium Synechocystis PCC 6803.
Cells are protected by their mantle of exopolysaccharides, from environmental stresses triggered by salts and/or metals
Furthermore, the increasing concerns related to energy availability and independence, and the negative environmental impact of using fossil fuels (pollution and climate change) make it important to develop renewable and environmentally-friendly energy sources. Cyanobacteria, the most abundant photosynthetic organisms on Earth, have the potentials for the production of renewable biofuels from nature’s most plentiful resources, solar light, water, mineral salts and the greenhouse gas CO2, while saving arable soils, fertilizers, pesticides and fresh waters for crops production. Indeed, cyanobacteria perform a powerful oxygen-producing photosynthesis; they are robust (they have colonized most waters and soils of our planet); and some strains have a powerful genetics. Their genetics is welcome as natural cyanobacteria are not suitable bio-fuel producers because some of the required metabolic pathways are lacking or need optimization.
Thanks to our long-standing expertise in cyanobacteria we use a “synthetic biology” approach to reprogram a few model cyanobacteria for the photo-production of ethanol, hydrogen and terpenes (the energy-dense compounds that can be blended with petroleum-based fuels to turn them into kerosene for aviation, i.e. jet-fuel).
Contact Franck Chauvat
In addition, we investigate the responses of cyanobacteria to the inter-twinned oxidative and metal stresses, which often limits the production of cyanobacterial biomass or high-value products (bio-fuels, vitamins, polysaccharides, etc).
Contact Corinne Cassier-Chauvat
DR - CEA
Corinne CASSIER CHAUVAT
DR - CNRS
DR - CNRS
CRCN - CNRS
Associate professor - UPsaclay
Monis Athar KHAN
C. Cassier-Chauvat, V. Blanc-Garin and F. Chauvat. 2021. Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes 12(4):500. https://doi.org/10.3390/genes12040500
For all the publications of the Team click on the button below.
AAPG2020: RevelOrg : Revelation of the light acclimation mechanism using parallel studies in different Organisms January 2021- December 2025
AAPG2019: HARLEY: Deciphering the mechanisms involved in the
hyperaccumulation of alkaline earth metals by cyanobacteria February 2020 January2024
AAPG2019: SPACEHex: SPATIAL control with HEXameric protein platforms January 2020-June 2023