For all I know they are regular BL21 cells and we are just given a different protocol:
Grow in minimal M9 media (basically salt water + .3% glycerol for a carbon source) instead of LB
Grow bacteria at RT instead of 37 degrees
Induce O/N at RT instead of 37 ~3hrs
So far it hasn't worked out too well; the cells hardly grow in this M9 media.
Edited by James W, 22 November 2010 - 03:31 PM.