Hi Jeremia,

Culture bacillus in a minimal media for 48 h and then heat the media in a water bath set to 65-70 deg C for 30 mins. Centrifuge the heated media at 10,000 g for 15 min. Collect the pellet and wash with 0.5 mM potassium hydroxide for 1 min and centrifuge at 10,000 g for 15 min. Wash the pellet with water 3 time by re-centrifuging to form pellets. You will have endospore free from cell debris.

All the best

Sporulate your culture using whatever method you prefer. Harvest everything and resuspend in 20% histodenz and layer on top of 50% histodenz. Centrifuge at 15,000 x g for 10-15 min. Spores will form a tight pellet, cell debris and any intact cells will be a band halfway up the tube. Discard the histodenz and then wash the pellet a couple of times with water to remove residual histodenz.