Gluten hydrolyzing activity of Bacillus spp isolated from sourdough

Abstract

Background Celiac disease is an intestinal chronic disorder with multifactorial etiology resulting in small intestinal mucosal injuries and malabsorption. In genetically predisposed individuals with HLA DQ2/DQ8 molecules, the gluten domains rich in glutamine and proline present gluten domains to gluten reactive CD4+ T cells causing injury to the intestine. In the present experimental design, the indigenous bacteria from wheat samples were studied for their gluten hydrolyzing functionality. Results Proteolytic activity of Bacillus spp. was confirmed spectrophotometrically and studied extensively on gliadin-derived synthetic enzymatic substrates, natural gliadin mixture, and synthetic highly immunogenic 33-mer peptide. The degradation of 33-mer peptide and the cleavage specificities of the selected isolates were analyzed by tandem mass spectrometry. The gluten content of the sourdough fermented by the chosen bacterial isolates was determined by R5 antibody based competitive ELISA. All the tested isolates efficiently hydrolyzed Z-YPQ-pNA, Z-QQP-pNA, Z-PPF-pNA, and Z-PFP-pNA and also cleaved 33-mer immunogenic peptide extensively. The gluten content of wheat sourdough was found to be below 110 mg/kg. Conclusion It has been inferred that four Bacillus spp especially GS 188 could be useful in developing gluten-reduced wheat food product for celiac disease prone individuals.

Characterization of Bacillus cereus AFA01 Capable of Degrading Gluten and Celiac-Immunotoxic Peptides

“…Three B. cereus strains can efficiently hydrolyze gluten and gliadin fragments. These results were in agreement with the previous study that the B. cereus isolated from sourdough exhibits glutenase activity [12]. The GA culture medium in which gluten is the only nitrogen source could afford a reliable means of isolating microorganisms with glutenase activity.…”

“…The tryptone and yeast in LB culture medium may be easy to be utilized by B. cereus AFA01, and the cells did not produce extra enzymes to hydrolyze the proteins, which may be the reason for low activity against the immunotoxic peptides. B. cereus can hydrolyze casein [33] and gluten [12], so AFA01 utilized the casein peptone, casein, and gluten. The SCB culture medium promoted the degradation of the immunotoxic peptides, which is consistent with the fact that casein can promote protease activity [34].…”

“…Recently, some gluten-degrading bacteria and gluten-degrading enzymes have been discovered and studied on the detoxification of gluten, such as Fusarium graminearum [10], Microdochium majus [11], Bacillus spp. [12], actinidin from kiwifruit [13], and a serine protease from Burkholderia gladioli [14]. Bacillus cereus can hydrolyze gluten and the 33-mer gliadin peptide [12], but some fragments that contain immunodominant T cell epitopes were released from the 33-mer peptide.…”

“…[12], actinidin from kiwifruit [13], and a serine protease from Burkholderia gladioli [14]. Bacillus cereus can hydrolyze gluten and the 33-mer gliadin peptide [12], but some fragments that contain immunodominant T cell epitopes were released from the 33-mer peptide. In the present study, we found that B. cereus AFA01 could be effective in degrading the 13-and 33-mer peptides and destroying the T cell epitopes in the 33-mer peptide.…”

Peptidomics: new trends in food science

“…Several evidences showed that sourdough fermentation reduced overall gliadin allergenicity [38]. Recently mass spectrometry was useful to demonstrate that Bacillus strains from wheat had proteolytic activities against the celiac epitopes, particularly 33-mer peptide from gliadin [39], whereas sourdough-related lactobacilli also degraded amylase-trypsin inhibitors in addition to gliadins [40]. The a-amylase/trypsin inhibitors have recently been identified as inducers of an innate immune response via toll-like receptor 4 in celiac disease and non-celiac wheat sensitivity [41].…”