Hydrochloric acid-treated Bacillus subtilis ghosts induce IL-1 beta, IL-6, and TNF-alpha in murine macrophage

Weissella koreensis and Pediococcus pentosaceus bacterial ghosts induce inflammatory responses as immunostimulants

In this study, bacterial ghosts (BGs) were generated from Weissella koreensis LKS42 (WKorGs) and Pediococcus pentosacues KA94 (PPGs) by chemically inducing lysis using substances such as hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), acetic acid (CH3COOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium carbonate (Na2CO3), n-butanol, and C6H8O7. HCl-induced WKorGs and PPGs exhibited complete removal of DNA and displayed transverse membrane dissolution tunnel structures under scanning electron microscopy (SEM). Cell viability assays showed high viability of RAW 264.7 cells exposed to HCl-induced WKorGs and PPGs. Additionally, treatment with HCl-induced WKorGs and PPGs elevated mRNA levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, iNOS) and the anti-inflammatory cytokine IL-10 in RAW 264.7 cells. These findings suggest that HCl-induced WKorGs and PPGs have the potential to be used as inactivated bacterial immunostimulants, highlighting their promising applications in immunization and immunotherapy.

Optimization of Sporulation Conditions for Bacillus subtilis BSNK-5

Bacillus subtilis spores have important biological applications; however, high spore-cell densities and sporulation efficiencies in fermentation is poorly reported. This study systematically analyzed the spore densities and formation efficiency of B. subtilis BSNK-5 in different culture substrates. A response surface regression equation was established based on the results of single factor and Box–Behnken experimental designs. The optimal medium formulation, as predicted from the equation, consisted of soluble starch at 3 g·L−1, soybean flour at 12 g·L−1, and MgSO4 at 5 g·L−1. The spore yield reached 2.43 × 109 CFU·mL−1, and the sporulation rate was 83.3%, which was nearly three times higher than before optimization using an optimized medium at 36 °C and 200 rpm for 60 h.