For ALE of the commercial C. ljungdahlii wild-type strain (DSMZ 13528), it was first inoculated in PETC medium (ATCC Medium 1754) containing 5.0 g L⁻¹ fructose (Figure ). The resulting culture was preserved with 20% glycerol at -80 °C, designated as Clwt. Subsequent transfers (trans1 to trans9, Figures and) involved gradually reducing the fructose concentration while maintaining the syngas concentration constant (25% CO, 10% H₂, 65% CO₂, 112 mL headspace) as carbon and energy sources. Then, the culture was grown exclusively on syngas over 11 transfers, with fructose removed entirely. Each transfer in both stages lasted 72 hours, with incubation at 37 °C and 150 rpm. The final adapted culture (trans20) was preserved similarly, and designated as Cladapt (Figure ). We monitored OD600 at the start and end of each transfer (Figure ), confirming consistent growth throughout the adaptation process.