Table 1 Strains and plasmids used in this study

JWCH001

C. hydrothermalis DSM 18901 wild -type (ura⁺/5-FOA^S)

JWCH006

C. hydrothermalis ΔpyrF (ura^-/5-FOA^R)

JWCH008

C. hydrothermalis ΔpyrF ΔchyI (ura^-/5-FOA^R)

JWCH009

C. hydrothermalis ΔpyrF harboring pJGW07 (ura⁺/5-FOA^S)

JW401

DH5α containing pJGW03 (Apramycin^R)

JW402

DH5α containing pJGW07 (Apramycin^R)

pDCW89

E. coli/Caldicellulosiruptor shuttle vector (C. bescii pyrF)

pDCW88

Caldicellulosiruptor non-replicating vector (C. bescii pyrF)

pDCW151

Caldicellulosiruptor chyI deletion vector (C. bescii pyrF)

pJGW03

Caldicellulosiruptor chyI deletion vector (C. thermocellum pyrF)

pJGW07

E. coli/Caldicellulosiruptor shuttle vector (C. thermocellum pyrF)