FORMATION OF HIGH-VALUE DENSE PLANT BIOCONDENSATES

Ziel

We need to turn our production systems upside down! Instead of using fossil fuels and release carbon dioxide, we need to shift to biobased production with carbon dioxide as the sole carbon source. In nature, this is already done at a scale feeding the worlds human population. The process used in nature is photosynthesis. This environmentally benign production system needs to be expanded to include the synthesis of high-value compounds that are not currently produced in photosynthetic systems or produced in low amounts. When produced in high amounts, these different types of high-value natural products need to be stored without being auto-toxic to the production host. This is where storage in dense biocondensates becomes a key success parameter. Biocondensate formation in plants is a black box, but proposed mechanisms point to phase partitioning induced by proteins with intrinsically disordered domains or by NAtural Deep Eutectic Solvents (NADES). NADES are compounds like sugars, amino acids, organic acids, and choline that when mixed in specific stoichiometric ratios have a lower melting point than the individual components. Certain plants manage to accumulate natural products in very high amounts without autotoxicity or cell homeostasis problems. This is the case in my two proposed experimental systems: Vanilla planifolia, which accumulates vanillin glucoside at 2.2kg/L levels in the plastids of the maturing pods; and Sorghum bicolor that produce the defence compound dhurrin, in amounts reaching 30% of the dry mass in etiolated seedlings. In order to identify the players involved in biocondensate formation, I will combine methods of cellular and organelle isolation with imaging and state-of-the-art analytic chemistry, metabolomics, and transcriptomics. Studying how plants orchestrate the formation of dense biocondensates to store high-value compounds in high amounts would be key to make green bio-production systems feasible.