Biochemical changes across a carbon saturation gradient: Lignin, cutin, and suberin decomposition and stabilization in fractionated carbon pools

► We examined biochemical composition of soil organic carbon (SOC) with C saturation. ► We measured plant biomarkers in soil C pools separated by protective mechanism. ► Lignin in SOC is depleted with increasing C saturation when not protected. ► SOC composition in the mineral fraction does not change with C saturation level. ► SOC biochemical composition does not affect long-term C stabilization and saturation.