Bacillus licheniformis is a ubiquitous bacterium thought to
be of importance in the environment as a contributor to nutrient
cycling due to the production of protease and amylase enzymes
(Claus and Berkeley, 1986). Although the actual numbers in
existence in the environment for this species have not been
determined, in general, bacilli occur at population levels of 106
to 10 per gram of soil (Alexander, 1977). B. cereus is isolated 7
most frequently from soils; however, this is thought to be due to
its ability to crowd-out other species in enrichment culture
rather than reflecting an actual predominance in soils (Norris et
al., 1981). Unless a soil has been recently amended with organic
matter which provides for readily utilizable nutrients for
vegetative cells, the bacilli exist predominately as endospores.
It is thought that between 60 to 100 % of soil populations of
Bacillus exist in the inactive spore state and that these
endospores are capable of surviving for many years.