Method for improving acid stress resistance of lactic acid bacteria and application thereof
A technology of lactic acid and lactic acid bacteria, applied in the field of microorganisms, can solve the problems of low survival rate of strains, large workload, low success rate, etc., and achieve the effects of extending product shelf life, improving product quality, and high success rate.
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
preparation example Construction
[0063] 1. Preparation of medium:
[0064] (1) Preparation of MRS liquid medium (1L): 10 g peptone, 5 g beef powder, 4 g yeast extract powder, 2 g dipotassium hydrogen phosphate, 2 g triammonium citrate, 5 g sodium acetate trihydrate, 20 g Glucose, 0.2 g magnesium sulfate, 0.05 g manganese sulfate, 1 mL Tween 80, add 1 L of distilled water, mix, boil and cool to room temperature, adjust the pH to 6.5 with 1 mol / L hydrochloric acid and 1 mol / L sodium hydroxide, divide Pack into test tubes, 10 mL / tube, and sterilize at 121°C for 15 min.
[0065] (2) Preparation of MRS solid medium (1 L): Based on the formula of MRS liquid medium, add 15 g of agar, adjust the pH to 6.5 with 1 mol / L hydrochloric acid and 1 mol / L sodium hydroxide, and pack in 250 mL cones. In a shaped bottle, sterilize at 121°C for 15 min.
[0066] (3) Cellobiose replacement medium (1L): Cellobiose was used to replace glucose in equal amounts, the replacement amounts were 5 g, 10 g, 15 g, and 20 g, respectively, a...
Embodiment 1
[0082] Embodiment 1 uses cellobiose and salicin gradient to replace glucose to cultivate Lactobacillus paracasei L9, and evaluates the bacterial strain after cultivation bgl Expression of key genes in operons and acid tolerance
[0083] 1.1 Effect of cellobiose treatment on the acid resistance of Lactobacillus paracasei L9
[0084] Using cellobiose 25%, 50%, 75%, 100% gradient instead of glucose to make cellobiose replacement medium, and analyze the effect of cellobiose on the acid resistance of L9.
[0085] Such as figure 1 As shown, the glucose in the MRS medium was replaced by cellobiose, compared with the MRS control group, under normal pH culture, the activities of the 25-cellobiose group, 50-cellobiose group, and 75-cellobiose group The number of bacteria increased significantly, indicating that the coexistence of cellobiose and glucose can promote the growth of Lactobacillus paracasei L9. However, when cellobiose was completely used as a carbon source, the number of...
Embodiment 2
[0099] Example 2 Effect of Salicin Treatment on the Heterogeneity of Lactobacillus paracasei L9 Acid Stress Response
[0100] At the subpopulation level, the effect of salicin on the heterogeneity of acid stress response of Lactobacillus paracasei L9 was analyzed. Lactobacillus paracasei L9 was cultured to the logarithmic phase (OD=0.6) using 25% salicin medium and MRS medium, stained with PI and SYTO dyes, and the subpopulation distribution at this time was analyzed by flow cytometry. The L9 cells in the logarithmic phase were subjected to acid lethal treatment for 60 min and 90 min, and the distribution of subpopulations after acid stress was analyzed by flow cytometry. The distribution ratio of each subgroup in three independent experiments was counted for data analysis.
[0101] Such as Figure 7 As shown, when Lactobacillus paracasei L9 was cultured to the logarithmic phase, that is, before the acid treatment, the complete living cell subpopulation and the damaged subpo...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More