This paper tackles two questions. Our first question addresses the multi-actor activity that is visibly required for building radical innovations like eco-innovation. Our second question addresses the tricky issue of how to assess contribution to ecological transition when innovation projects are still in the fuzzy early-upstream phase. In this aim four research projects are selected and analyzed in this paper because they share a common scope—the development of new processes or materials tied to the conversion of biomass. Through the analysis of the actors interactions conducted in these projects, of their perimeters, of their sustainability objectives and of their results we show a limit of the eco-innovation capacity of these projects linked to the limits of their crossdisciplinarity.