BL21 Electro­competent Prep
Dilute 5mL O / N into 500mL LB .
Grow to OD 0.6­ - 0.8 ( ~ 1.5­ - 3 hours ) .
Pour into 2x250mL Centrifuge bottles .
Chill bottles on ice for 10 minutes .
Spin at 3000xg for 20min at 4C .
Decant supernatant .
Resuspend + combine pellets in 250mL pre­chilled 10 % glycerol .
Spin at 3000xg for 20min at 4C .
Decant supernatant .
Resuspend pellet in 20mL pre­chilled 10 % glycerol ( switch to 50mL Falcon Tube ) .
Spin at 3000xg for 20min at 4C .
Decant supernatant .
Resuspend in 3mL pre­chilled 10 % glycerol .
SNAP Freeze in 25­50uL aliquots in LN2 .
