Optimization of bacteriocin production by Lactobacillus plantarum ST13BR, a strain isolated from barley beer

Abstract

The cell-free supernatant containing bacteriocin ST13BR, produced by Lactobacillus plantarum ST13BR, inhibits the growth of L. casei, Pseudomonas aeruginosa, Enterococcus faecalis, Klebsiella pneumoniae and Escherichia coli. Based on tricine-SDS-PAGE, bacteriocin ST13BR is 10 kDa in size. Complete inactivation or significant reduction in bacteriocin activity was observed after treatment with Proteinase K, trypsin and pronase, but not with catalase or a a-amylase. Low bacteriocin activity (200 AU/ml) was recorded in BHI medium, M17 broth, 10% (w/v) soy milk, and 2% and 10% (w/v) molasses, despite good growth. Maximal bacteriocin activity (6,400 AU/ml) was recorded after 23 h in MRS broth, but only at 30°C. Tween 80 in MRS broth increased bacteriocin production by more than 50%. Meat extract or yeast extract as sole nitrogen source, or a combination of the two (1 : 1) in MRS broth, stimulated bacteriocin production (6,400 AU/ml). Only 50% activity (3,200 AU/ml) was recorded with tryptone as sole nitrogen source, whereas a combination of tryptone, meat extract and yeast extract yielded 6,400 AU/ml. Bacteriocin production was not stimulated by the addition of glucose at 2.0% w/v (3,200 AU/ml), nor 2% (w/v) fructose, sucrose, lactose or mannose, respectively (800 AU/ml). Activity levels less than 200 AU/ml were recorded in the presence of 0.05% to 0.5% (w/v) maltose. Maximal bacteriocin production (6,400 AU/ml) was recorded in the presence of 2% (w/v) maltose. Maltose at 4.0% (w/v) led to a 50% reduction of bacteriocin activity. The presence of 1.0% (w/v) and higher KH 2 PO 4 , or glycerol at 0.2% (w/v) suppressed bacteriocin production.

Antimicrobial Activity of a Bacteriocin Produced by Lactobacillus Plantarum 29V and Strain′S Viability in Palm Kernel Oil

“…The Neutralized cell-free supernatant of L. plantarum 29V culture demonstrated inhibitory activity of 1600AU/ml, which decreased to 800AU/ml after partial purification using 60% ammonium sulfate precipitation. This is in agreement with the findings of Todorov et al [15] reporting the loss of plantaricin ST31 activity from 6.4 x 10 5 to 2.5 x 10 5 AU/ml after 60% ammonium sulfate precipitation. Since inhibition was observed when the pathogens were grown in the presence of near-neutral supernatant (pH 6.5), inhibition effects could not be attributed to organic acids production, but probably to hydrogen peroxide or bacteriocin-like substances production.…”

Characterization and Optimization of Bacteriocin from <i>Lactobacillus plantarum</i> Isolated from Fermented Beef (Shermout)

“…plantarum (ST28MS and ST26MS) showed detectable levels of inhibitory activity after 5 h suggesting that the peptide is a primary metabolite. Similar results were also reported for plantaricin Y [52] and bacteriocin ST13BR [53]. Both maximum growth and inhibitory activity were obtained at pH 4.4 -4.2.…”

Pre-treatment of growth medium with Amberlite® XAD-1180 produces higher levels of bacteriocin plantaricin 423

“…Similarly, L. plantarum ST414BZ and ST664BZ yielded optimal bacteriocin activity when cultured in medium containing tryptone as sole nitrogen source [21] while increased activity for bacteriocins ST13BR, ST414BZ, ST664BZ and ST194BZ have also been reported in minimal growth media [21][22][23]. In addition, helveticin J production can also be stimulated when cells are grown in the presence of both yeast and meat extracts [24].…”