Given the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC), the announced depletion of fresh water, the indiscriminate use of toxic chemicals and the impact of all these drifts on the future of our planet and on biodiversity, new production methods of biosourced molecules, less energy-consuming, not generating CO2 and less demanding in fresh water must be investigated to ensure a credible and sustainable transition. In line with these concepts, the EPPIC project proposes to investigate 3 different routes for polymer production starting from sugar by-products or CO2 in sea water. Enzymatic routes with multiples natural or evolved enzymes, cell-based processes involving engineered microorganisms and hybrid processes combining cell-free and cell-based systems will be developed. These innovative production routes will be evaluated using an eco-design and life cycle assessment approach to identify the most promising production routes and to assess their energy and environmental performances.