K15F5 medium.

Reagent	Amount	Final concentration
KnockOut DMEM (Gibco#10829–018)	76 mL
KnockOut serum replacement (KSR) (Invitrogen#10828–028)	15 mL	15%
Fetal bovine serum embryonic stem cell qualified (ES-FBS) (Bio-Techne#S10250)	5 mL	5%
Penicillin-streptomycin (100 x) (Gibco#15070–063)	1 mL	1 ×
l-Glutamine (200 mM) (Gibco#25030)	1 mL	2 mM
MEM non-essentials amino acids (100 ×) (Gibco#11140–050)	1 mL	1 ×
β-Mercaptoethanol (10 mM) (Sigma#M7522)	1 mL	0.1 mM

Filter and store the medium (final volume 100 mL) at 4°C and use within 2 weeks. Prepare β-mercaptoethanol 10 mM stock from 14.3 M stock (Sigma-Aldrich M7522) by adding 6.25μL to 9 mL of sterile distilled water.