Hello to all. I have recently been working on growth and sporulation of B.coagulans BC30 (isolated from a probiotic product which was claimed to contain it) and I have had problems with its sporulation. Based on my experience, sporulation in B.coagulans is not as simple as other Bacillus species. This isolate sporulates just on “sporulation agar medium” after 48 hours (I did not see any spores in Nutrient agar or MRS agar even when the agar medium had been dried and cracked caused by long incubation time at 48°C). I need this bacterium to grow well and sporulate in broth medium but spores could not be seen even after one week of fermentation (in a rich medium containing glucose, peptone, yeast extract, and minerals such as MnSO4 0.17 g/l and MgSO4 0.25 g/l). Then, I used minerals such as FeSO4 (0.00028 g/l), Mncl2 (0.0016 g/l), CaCl2 (0.073 g/l) and MgSO4 (0.25g/l) in the culture medium (in concentrations similar to sporulation agar medium) and incubated it at 48°C for 85 hours, but again no spores were formed. I used a rich medium to improve its growth, so I guessed that nutritional enrichment suppressed sporulation, however even in “sporulation broth medium” with low nutrients, no spores were observed after 3 days. Apparently, for this bacterium, nutritional depletion could not induce sporulation alone. I don’t know what the problem is? Does sporulation depend on a factor that I have not applied? Lower or higher growth temperature? Heat shock? Cold shock? Oxygen restriction? Or…?