Studies On The Transformation Of Organic Selenium,Fermentation Of Traditional Chinese Medicine Residues,and Immunomodulatory Ability Of Bacillus Subtilis(JE21)

Bacillus subtilis is a commonly used microorganism with the ability to promote fermentation,regulate intestinal microflora,improve body immunity,and improve animal growth performance.It is a safe probiotics with broad application prospects.Bacillus subtilis can not only convert inorganic selenium with high toxicity and low bioavailability into organic selenium with low toxicity and high bioavailability,but can be used as a safe biological selenium supplement carrier.Bacillus subtilis also has a strong fermentation and decomposition ability,making it have the potential for fermentation treatment of traditional Chinese medicine residues,which is of great significance for the deep utilization of traditional Chinese medicine residues.This thesis utilizes the excellent selenium conversion and fermentation capabilities of Bacillus subtilis to optimize and improve the efficiency of organic selenium conversion while fermenting the traditional Chinese medicine residue of Sijunzi Decoction.Not only has a safe and effective selenium supplement probiotics been discovered,but also a method has been obtained to improve the bioactive components such as saponins and flavonoids in the traditional Chinese medicine residue of Sijunzi Decoction.At the same time,the immunosuppressive model of BALB/c mice induced by cyclophosphamide（CTX）was established to evaluate the immunomodulatory effects of SeJE21 and Sijunzi decoction residue fermentation（SDRF）on immunosuppressive mice.The specific research work includes:1.Using traditional fermented pickle juice as the research material,a strain of selenium tolerant Bacillus subtilis JE21 was obtained through screening and purification,which grew well under the conditions of high Na₂SeO₃ concentration（50m M）;Through screening and optimizing the cheap medium for JE21 strain,it was determined that the optimized cheap medium group had a carbon source ratio（glucose:yeast powder）of 3:5（0.5 g:0.83 g）,a nitrogen source ratio（urea:fish meal:soybean meal）of 1:1:10（0.3 g:0.2 g:2 g）,and an inorganic salt ratio（MnSO₄:MgSO₄:NaCl）of 1:25:20（0.002 g:0.05 g:0.04 g）.When the bacterial culture reached the same biomass,The optimized low-cost medium reduces the cost by 44.83%compared to LB liquid medium,providing a low-cost medium formulation for subsequent large-scale JE21 culture;2.By optimizing the selenium enriched culture conditions of JE21 strain,it was found that the organic selenium conversion rate reached a maximum value of 94.61±0.82%when the concentration of Na₂SeO₃ in the cheap optimized culture medium was 1 m M,the addition time of Na₂SeO₃ was the 8th hour after the start of culture,and the inoculation amount of JE21 strain was 4%,providing a technical basis for obtaining a safe probiotic containing selenium,SeJE21;3.The single factor method was used to optimize the fermentation conditions of the traditional Chinese medicine residue of Sijunzi Decoction,which contains the same components of medicinal and edible ingredients as JE21.The process conditions for significantly increasing the content of total flavonoids,total saponins,and other bioactive components were obtained.The results showed that when the nitrogen source was 2%corn gluten meal,the inoculum amount was 6%,the material liquid ratio was 1:20,the fermentation temperature was 30℃,and the fermentation time was 60 h,the total saponin content increased from 13.07 mg/g before fermentation to25.31 mg/g after fermentation,increasing to 1.94 times.The total flavonoids content increased from 3.81 mg/g before fermentation to 5.99 mg/g after fermentation,increasing to 1.57 times,providing an effective way for the microbial treatment and utilization of such traditional Chinese medicine residues.4.To establish an immunosuppressive model of BALB/c mice induced by cyclophosphamide（CTX）,and evaluate the immunomodulatory effects of SeJE21 and Sijunzi Decoction residue fermentation（SDRF）by body weight changes,spleen index,blood and serum physiological indicators.Collect anticoagulant whole blood for blood indicators such as white blood cell（WBC）,lymphocyte（LYM）,monocyte（MON）,red blood cell（RBC）,and platelet（PLT）counts.After centrifuging the rest of the whole blood,take the serum for serum physiological indicators:miceγInterferon（IFN-γ）And the detection of mouse interleukin-4（IL-4）,interleukin-6（IL-6）,and interleukin-10（IL-10）content.It was found that SeJE21 freeze-dried powder combined with SDRF freeze-dried powder can repair immune organ damage,regulate the content of cytokines in serum,and effectively improve the immunosuppression induced by cyclophosphamide（CTX）in mouse models,indicating that SeJE21 and SDRF have certain prospects in the application field of enhancing immunity.