Tryptophan auxotroph (trpC2) and chloramphenicol resistance (cat)
Bacillus subtilis 168
The detailed procedures for the construction of the strain are described in the paper entitled "Bacillus subtilis mutants harbouring a single copy of the rRNA operon exhibit severe defects in growthand sporulation (Microbiology.  156 : 2944 - 2952)"
L-broth, Difco sporulation medium (DSM), two-strength Schaeffer's sporulation medium supplemented with glucose (2xSG), and so on.
Nanamiya H, Sato M, Masuda K, Sato M, Wada T, Suzuki S, Natori Y, Katano M, Akanuma G, Kawamura F.
Bacillus subtilis mutants harbouring a single copy of the rRNA operon exhibit severe defects in growth and sporulation.
[PubMed ID = 20634236]