Why is not possible to light a bulb without closing a circuit by using two batteries
You may have a look at this site: http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/electrochem.html


"In order for the voltaic cell to continue to produce an external electric current, there must be a movement of the sulfate ions in solution from the right to the left to balance the electron flow in the external circuit"

Because that ions can't move between the two batteries, your bulb will not produce light.