Production of bacteriocin ST33LD, produced by Leuconostoc mesenteroides subsp. mesenteroides, as recorded in the presence of different medium components.

摘要

Bacteriocin ST33LD, produced by Leuconostoc mesenteroides subsp. mesenteroides, is approx. 2.7 kDa in size and inhibits Enterococcus faecalis, Escherichia coli, Lactobacillus casei and Pseudomonas aeruginosa. Effects of culture medium composition and pH on production of bacteriocin ST33LD by L. mesenteroides were investigated. Good bacterial growth was recorded in the presence of 10% (w/v) soymilk or molasses, but no bacteriocin production was detected. Growth in MRS broth adjusted to pH 4.5 yielded a low bacteriocin activity (800 U/ml). However, MRS broth adjusted to pH 5.0, 5.5 or 6.5 yielded 3200 U/ml. Addition of Tween 80 decreased bacteriocin production by >50%. Growth in the presence of tryptone yielded max. activity (12 800 U/ml), whereas combinations of tryptone, meat extract and yeast extract produced activity levels of 1600 U/ml. Growth in the presence of 2.0% (w/v) sucrose or maltose produced bacteriocin at 12 800 U/ml, whereas the yield using 2.0% (w/v) glucose or lactose was 6400 U/ml. Lower yields were also recorded with fructose and mannose. KH2PO4 at 10.0% (w/v) stimulated bacteriocin production. Glycerol at 0.5-5.0%, w/v repressed bacteriocin production by 50%. Addition of cyanocobalamin, thiamine and L-ascorbic acid to MRS broth (1.0 ppm) yielded bacteriocin at 12 800 U/ml, whereas addition of DL-6,8-thioctic acid yielded only 6400 U/ml.