Biofilm formation and sporulation in Brevibacillus laterosporus

Abstract

Spore accumulation in Brevibacillus laterosporus in a liquid nutrient medium under optimal conditions during stationary cultivation was investigated. The structure of floating biofilms was studied by transmission and scanning electron microscopy. It was shown that B. laterosprus cells formed a biofilm within 96 h of incubation. The accumulation of spores and individual vegetative cells in the biofilm was confirmed by light microscopy. The spore ultrastructure was shown to depend on the richness of the media. As was shown for the first time, B. laterosprus had an unusual morphology when grown in a yeast polysaccharide medium. A difference between B. laterosprus and Bacillus subtilis biofilms concerning the vegetative cells and spores was observed. In B. subtilis biofilm, the vegetative cells are numerous and devoid of the defects that are characteristic of B. laterosprus. The results may be helpful in optimizing bacilli-based biotechnological processes aimed at improving the yield of target products.