Lactococcus lactis fermentation medium on the basis of bean pulp protein enzymatic hydrolysate and method for preparing lactococcus lactis fermentation medium

Abstract

The invention discloses a lactococcus lactis fermentation medium on the basis of bean pulp protein enzymatic hydrolysate and a method for preparing the lactococcus lactis fermentation medium. The method for preparing the lactococcus lactis fermentation medium includes weighing 300-500 mL of bean pulp protein enzymatic hydrolysate, 12 g of sucrose, 25 g of monopotassium phosphate, 1.5 g of sodium chloride, 0.05 g of magnesium sulfate, 0.2 g of cysteine and the balance distilled water to obtain 1000 mL of liquid; uniformly mixing the liquid; regulating a pH (potential of hydrogen) value of the liquid; sterilizing the liquid. The lactococcus lactis fermentation medium and the method have the advantages that macromolecular protein peptide bonds are broken after bean pulp is subjected to enzymatic hydrolysis by the aid of protease, and accordingly, low-molecular-weight polypeptides and free amino acids with different relative molecular weights can be obtained, the molecular weights are far smaller than the molecular weight of nisin, and the nisin can be separated and purified advantageously in later periods; the bean pulp protein enzymatic hydrolysate is used as a nitrogen source in the fermentation medium for producing strains for the nisin, is widely and easily available and low in cost, waste can be utilized, resource wastage can be reduced, and the fermentation cost can be lowered to a great extent; the bean pulp contains probiotics multiplication factors, and accordingly, growth of lactic acid bacteria can be promoted, and the yield of the nisin can be increased.

Description

technical field [0001] The invention relates to a lactococcus lactis fermentation medium and a preparation method thereof, belonging to the field of biotechnology. Background technique [0002] Nisin, also known as nisin, is a small molecule polypeptide antibiotic substance produced by the fermentation of certain lactic acid bacteria. It contains 34 amino acid residues and has a relative molecular mass of 3510Da. Nisin has an inhibitory effect on most Gram-positive bacteria and some Gram-negative bacteria, and has a strong inhibitory effect on common pathogenic bacteria and spoilage microorganisms in food. Nisin is sensitive to protease, and can be quickly hydrolyzed by chymotrypsin in the human digestive tract. It will not accumulate in the human body, nor will it change the normal flora in the human intestinal tract. Its semi-lethal dose is about 7.0g / kg (body weight), which is similar to ordinary table salt, is an internationally recognized food preservative with high e...

AI Technical Summary

Problems solved by technology

There is no report on the use of soybean meal protein hydrolyzate as a component of lactic acid bacteria fermentation medium