Encapsulation of beneficial probiotic bacteria in extracellular matrix from biofilm-forming Bacillus subtilis

Abstract

Probiotics, live microbial supplements, are often incorporated into foods and beverages to provide putative health benefits. To ensure their beneficial effects, these organisms must survive processing and storage of food, its passage through the upper gastrointestinal tract (GIT), and subsequent chemical ingestion processes until they reach their target organ. However, there is considerable loss of viability of probiotic bacteria in the acidic conditions of the stomach and the high bile concentration in the small intestine. Bacillus subtilis, a spore-forming non-pathogenic bacterium, recently has gained interest in its probiotic properties; it can effectively maintain a favorable balance of microflora in the GIT. In addition, B. subtilis produces an extracellular matrix that protects it from stressful environments. We suggested that the extracellular matrix produced by B. subtilis could protect other probiotic bacteria and therefore potentially could be used as a vehicle for delivering viable probiotic cells to humans. Therefore, we developed a novel cultivation system that enables co-culturing of B. subtilis along with probiotic lactic acid bacteria (LAB) by increasing production of the extracellular matrix by B. subtilis cells. Moreover, we showed that B. subtilis improved survivability of LAB during food preparation, storage and ingestion. Therefore, we believe that the results of our study will provide a novel technique of using a natural system for preservation and delivery of probiotics to humans.

The Stress-Responsive Alternative Sigma Factor SigB of Bacillus subtilis and Its Relatives: An Old Friend With New Functions

“…By contrast, the co-culture of B. subtilis under biofilm-supporting conditions favored the growth and survival of probiotic lactic acid bacteria (LAB), protected in the extracellular matrix of the biofilm formed by B. subtilis. Otherwise, LABs would perish upon exposure to the acidic pH of the stomach and the microbicide action of intestinal bile (Yahav et al, 2018). More recently, it has been shown in animal models that the B. subtilis biofilm is important in delaying neurodegenerative diseases (i.e., Alzheimer's and Parkinson's diseases) (Cogliati et al, 2019;Goya et al, 2020).…”

Characterization, health benefits and applications of fruits and vegetable probiotics

“…Associated with reduced incidences of colorectal cancer (Parvez, Malik, Ah Kang, & Kim, 2006) Bacillus subtilis Stimulates the immune system, reduce frequency of infections, has antagonistic effect on H. pylori infection, also has protective effect on other LAB during food processing, storage and in the GIT (Lefevre et al, 2017, Lefevre et al, 2015Pinchuk et al, 2001;Yahav, Berkovich, Ostrov, Reifen, & Shemesh, 2018)…”

The promises and risks of probiotic Bacillus species

“…Popular supporting materials used in microencapsulation extrusion techniques include alginate solutions (algae derived heteropolysaccharides), whey proteins, pectin, milk or human-like collagen (Chávarri et al, 2012;Martín et al, 2015). A probiotic B. coagulans strain was successfully encapsulated using polysaccharides, chitosan and alginate (Anselmo et al, 2016), while the extracellular matrix produced by B. subtilis is proposed to serve as a protectant for other probiotic bacteria in complex preparation (Yahav et al, 2018). The addition of cryo-protectants such as glucose, maltodextrin, trehalose, skimmed milk powder, whey protein or novel soybean flour additionally increases the survival rates and the activity of intracellular enzymes of the freeze-dried encapsulation probiotics, as demonstrated for B. subtilis starter cultures or LAB (Martín et al, 2015, Mahidsanan et al, 2017.…”