The biofilm formation took place in 48 h within the solid substrate cultivation of Lactobacillus plantarum 8-RA-3 strain on the wheat bran saturated with the MRS medium. The drying of the bran fermented by lactobacilli resulted in a decrease in the number of colony-forming units (CFU) from 23.0 × 10(8) to 6.9 × 10(5) CFU/g in daily samples and to less than 10(4) CFU/g in 2- and 3-day samples. However, according to the fluorescence-based live/dead assay data, more than 40 % of the non-cultured bacteria were viable. As a result of mice kept on a diet with the introduction of bran fermented by Lact. plantarum 8-RA-3 for 72 h into the fodder, a recovery of normal level of intestinal lactobacilli, inhibited by administration of antibiotic was noted. The strain genetically identical to the Lact. plantarum 8-RA-3 was isolated from the feces of these mice. The results indicate that solid substrate cultivated Lact. plantarum 8-RA-3 strain formed a biofilm. Once dried and transferred into a non-cultured state, biofilm cells retained its viability and biological activity.
Keywords: Biofilm; Lactobacillus plantarum; Non-cultured cells; Probiotics; Solid substrate cultivation; Wheat bran.