Preparing a plating stock of bacteria
to 200ml LB add 4 ml 10% Maltose (to = 0.2%)
add either a single plaque or 1 ml of a pregrown bacterial strain (P2 for instance)
shake at 300 rpm, 37oC overnight (or until you have sufficient growth)
centrifuge at 4000 g for 10 min.
bring up bacterial pellet in 80 ml (40% of original volume) of 10mM MgSO4
store at 4oC