Design-led comparison of photosynthetic biomineralisation workflows through waste-derived material sample collections for circular product design

This paper presents an observational comparative study of three photosynthetic biomineralisation workflows: gelatine-based hydrogel, liquid non-gel and alginate-based hydrogel systems. Each workflow was applied to eleven waste-derived materials across the food, wood, paper, textile and ceramic waste categories, resulting in three proof-of-concept material sample collections. These collections were used as design research artefacts to compare the fabrication processes and material outcomes of each workflow. The workflows were assessed through five design-led criteria: workflow feasibility, resource inputs, visible cyanobacterial retention, material qualities and preliminary biomineralisation indicators. Results show distinct trade-offs: the gelatine system offered reliable casting and structural stability; the non-gel system reduced binder use and retained a stronger visible cyanobacterial presence; and the alginate system enabled subsequent cultivation but led to dimensional instability in the resulting samples. Rather than identifying a single optimal fabrication method, the study provides an early basis for adapting photosynthetic bio- mineralisation workflows for circular product design.