Market-based variant of Spiber Brewed Protein™ fiber, a bio-engineered protein fiber inspired by spider silk and produced by precision fermentation of plant-based sugars. Same product and same ISO 14044 critically reviewed LCA (Spiber, final report 18 May 2026) as the main Spiber Brewed Protein™ fiber entry. The only difference is how Spiber's own electricity is accounted for: here it is modelled with energy attribute certificates (retired I-RECs from biomass for polymer production in Thailand, non-fossil certificates from solar PV for fiber production in Japan). Use this entry only if your organisation applies market-based accounting for purchased electricity. For location-based (grid-average) accounting, consistent with the rest of the Carbonfact library, use the main Spiber Brewed Protein™ fiber entry.