Preparation method of spirulina antibacterial peptide composite membrane

[0024] Example 1

[0025] 1) Preparation of spirulina antimicrobial peptides: add 6g of spirulina powder to 120mL, pH=7.0 sodium phosphate buffer solution, freeze and thaw at -20℃, thaw at room temperature three times, freeze and centrifuge at 4℃ for 30 min , Then take the supernatant, add neutral protease in the amount of 0.0125g/100mL, enzymatically hydrolyze at 45 ℃ for 4 h, during which the pH value is maintained at 7.0, the enzymatic hydrolysate is heated in a water bath at 95 ℃ for 10 min to inactivate the enzyme. After 30 minutes of freezing and centrifugation at 4°C, the supernatant was vacuum freeze-dried to obtain the spirulina antimicrobial peptide;

[0026] 2) Preparation of nano-titanium dioxide: wash the titanium dioxide with deionized water and dry, then add absolute ethanol according to the mass-volume ratio of 1g:20mL, ball mill for 48 h, and filter to obtain nano-titanium dioxide;

[0027] 3) Preparation of composite membrane: add 0.6g spirulina antimicrobial peptide, 1.2 g nano titanium dioxide, 1 g sodium alginate, 0.5 g glycerol, 0.1 g polyethylene glycol 1000 to 10 mL absolute ethanol and deionized water Dissolve in the formed composite solvent (1:20, v/v), then add the composite solvent to the total volume of the solution to 100 mL, stir and sonicate it for 30 minutes under the conditions of vacuum 100-300Pa and power 250W to make it uniform. During this period, the ultrasonic frequency is changed cyclically in the range of 40kHz~55kHz, the change method is 0.1s change once, each change is 100Hz, after ultrasonic, the solution is poured into the mold, dried at 60 ℃ for 3 h, cooled to room temperature, and then peeled off. Spirulina antimicrobial peptide composite film.

[0028] Example 2

[0029] 1) Preparation of spirulina antimicrobial peptides: add 6g of spirulina powder to 120mL, pH=7.0 sodium phosphate buffer solution, freeze and thaw at -20℃, thaw at room temperature three times, freeze and centrifuge at 4℃ for 30 min , Then take the supernatant, add neutral protease in the amount of 0.0125g/100mL, enzymatically hydrolyze at 30 ℃ for 8 h, during which the pH value is maintained at 7.0, the enzymatic hydrolysate is heated in a water bath at 95 ℃ for 10 min to inactivate the enzyme, again After 30 minutes of freezing and centrifugation at 4°C, the supernatant was vacuum freeze-dried to obtain the spirulina antimicrobial peptide;

[0030] 2) Preparation of nano-titanium dioxide: wash the titanium dioxide with deionized water and dry, then add absolute ethanol according to the mass-volume ratio of 1g:20mL, ball mill for 48 h, and filter to obtain nano-titanium dioxide;

[0031] 3) Preparation of composite membrane: 1 g spirulina antimicrobial peptide, 2 g nano titanium dioxide, 2 g gelatin, 1 g glycerol, 1 g polyethylene glycol 2000 are added to 10 mL absolute ethanol and deionized water to form Dissolve in a composite solvent (1:20, v/v), then add the composite solvent to a total volume of 100 mL. After stirring, perform ultrasonic mixing for 30 minutes under the conditions of a vacuum of 100-300 Pa and a power of 250 W. The ultrasonic frequency changes cyclically in the range of 25kHz~35kHz, the change method is 0.2s once, each change is 100Hz, after ultrasonic, the solution is poured into the mold, dried at 60 ℃ for 3 h, cooled to room temperature and then peeled off, the spirulina is obtained. Antimicrobial peptide composite membrane.

[0032] Example 3

[0033] 1) Preparation of spirulina antimicrobial peptides: add 6g of spirulina powder to 120mL, pH=7.0 sodium phosphate buffer solution, freeze and thaw at -20℃, thaw at room temperature three times, freeze and centrifuge at 4℃ for 30 min , Then take the supernatant, add neutral protease in the amount of 0.0125g/100mL, enzymolyze at 70 ℃ for 2 h, during which the pH value is maintained at 7.0, the enzymatic hydrolysate is heated in a water bath at 95 ℃ for 10 min to inactivate the enzyme, again After 30 minutes of low-temperature freezing and centrifugation, the supernatant was taken and vacuum freeze-dried to obtain the spirulina antimicrobial peptide;

[0034] 2) Preparation of nano-titanium dioxide: wash the titanium dioxide with deionized water and dry, then add absolute ethanol according to the mass-volume ratio of 1g:20mL, ball mill for 48 h, and filter to obtain nano-titanium dioxide;

[0035] 3) Preparation of composite membrane: Add 3 g of spirulina antimicrobial peptide, 3 g of nano-titanium dioxide, 3 g of hydroxypropyl methylcellulose, 3 g of sorbitol, 1.5 g of polyethylene glycol 1000 to 10 mL of absolute ethanol and Dissolve in a composite solvent (1:20, v/v) formed by deionized water, then add the composite solvent to a total volume of 100 mL, stir and ultrasonicate for 30 minutes under the conditions of a vacuum of 100-300Pa and a power of 250W. During mixing, the ultrasonic frequency is cyclically changed in the range of 20kHz~60kHz, the change method is 0.1s change once, each change is 200Hz, after ultrasonic, the solution is poured into the mold, dried at 60 ℃ for 3 h, and then peeled off after cooling to room temperature , That is, the spirulina antimicrobial peptide composite film