Viability of dormant and superdormant spores on various media with and without heat activationa

Bacillus species and plating mediumSpore viability (%)b
No heat activationHeat activation
B. cereus and LB4011003
B. cereus and LB + alanine/inosine8811010298
B. megaterium and LB8741005
B. megaterium and LB + glucose/proline107100100108
B. subtilis and LB871.510010
B. subtilis and LB + AGFK/valine1059510096
  • a Dormant (D) and superdormant (SD) spores at an OD600 of 1 were heat activated at the temperature optima for dormant spores, cooled, and applied to LB medium plates without or with the mixture of the original and alternate germinants; the plates were incubated at 30°C (B. megaterium) or 37°C (B. cereus and B. subtilis) for 24 to 36 h; and colonies were counted.

  • b Spore viability is expressed relative to that of heat-activated dormant spores of the same species on LB medium plates, and this latter value was set at 100%.