Studies on Sporulation Optimization and Chracterization of Bacillus subtilis Spore Quality

摘要

Manganese-Amended Nutrient Agar is the media currently used by the U.S. Environmental Protection Agency for the production of Bacillus subtilis spores. The cells require 12-14 days to sporulate. Our goal was to conduct a study exploring replacement of the current media to minimize the incubation period and generate high quality B. subtilis spores. An extensive literature review was performed to investigate widely accepted methods used for sporulation of B. subtilis. Based on the results of this review, three media were investigated: Synthetic Sporulation Medium, 2xSG, and Long Version Nutrient Agar. The selected formulations or close variations have extensively been used by other researchers. These formulations represent two extreme ends of the spectrum (i.e., fully defined to undefined or complex). They have been used depending on specific objectives (i.e., molecular versus spore production). The Synthetic Sporulation media (either agar or broth versions) yielded poor results, with no sporulation of B. subtilis during a 14 day monitoring period. Sporulation was completed within 7- 9 days of incubation in the other two media. Finally, heat and bleach resistance were recommended in place of acid resistance as indicators of spore hardiness.