Temperature-resistant and acid-alkali-resistant strain, screening method, microbial inoculum and application

[0049] The present embodiment is the screening method of Bacillus urea L2, which comprises the following steps:

[0050] (1) Isolation of strains

[0051] Composted product samples from the food waste composting plant in Shijiazhuang City, Hebei Province were passed through LB solid medium (formulation: tryptone 10g / L, yeast extract 5g / L, NaCl 10g / L) to isolate and obtain 21 bacterial strains, which were plate-passaged 5 times to obtain stable genetic monoclonal strains, and stored at -80°C.

[0052] (2) Preliminary screening of strains with high temperature resistance and high activity cellulase

[0053] The isolated 21 monoclonal strains were treated with cellulose Congo red medium (recipe: sodium nitrate 1.0g, disodium hydrogen phosphate 1.2g, potassium dihydrogen phosphate 0.9g, magnesium sulfate 0.5g, potassium chloride 0.5g, yeast leaching 0.5g powder, 0.5g acid hydrolyzed casein, 0.2g Congo red, 5.0g cellulose powder, 15.0g agar, pH 7.0±0.1, 1000ml distilled water

[0065] This embodiment relates to the identification of physiological characteristics of Bacillus urea L2, including the identification of high temperature resistance and acid and alkali resistance, the method is as follows:

[0066] (1) Streak-inoculate Bacillus geourea L2 stored at -80°C on LB solid plates (see above for recipe), and inoculate them at 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, and 70°C, respectively. , 75°C, 85°C and 90°C for 3 days, and observe the growth status of bacterial strain L2 under different temperature conditions, the results are shown in Table 2:

[0067] Table 2 Growth status of L2 at different temperatures

[0068]

[0069] Note: + indicates that it can grow (there are colonies on the solid medium), ++ grows well (the number of colonies on the solid medium is 10-50), +++ grows vigorously (the number of colonies on the solid medium is greater than 50) indivual).

[0070] It can be seen from Table 2 that Bacillus urea L2 can grow well on LB medium und

[0077] This example relates to the identification of enzyme-producing activities of Bacillus urea L2, including producing lipase, protease and cellulase. The identification method is as follows:

[0078] (1) Verify the lipase-producing ability of the Bacillus urea L2 strain: activate the L2 strain and inoculate it into the nutrient broth medium (peptone 10g / L, beef powder leaching powder 3g / L, sodium chloride 5g / L, pH 7.2±0.2), cultured at 60°C for 24h. The activity of lipase in culture medium was determined by alkaline titration. It was determined that the activity of lipase in the culture medium was 10.2U / mL.

[0079] (2) The L2 strain was activated and inoculated into 50 mL of skimmed milk powder medium (10 g of peptone, 3 g of beef extract, 5 g of sodium chloride, 1.5 g of skim milk powder, and 1000 ml of distilled water), and cultured at 50°C for 24 hours. The protease activity in the mixture was determined by the Folin-phenol method. It was determined that the