Partial purification and characterization of a broad‐spectrum bacteriocin produced by a Lactobacillus plantarum zrx03 isolated from infant's feces

Abstract

Lactobacillus plantarum zrx03 was a bacteriocin-producing strain isolated from infant's feces. The fermentation supernatant produced by this strain could strongly inhibit Escherichia coli JM109 ATCC 67387, Staphylococcus aureus ATCC 25923, and Listeria monocytogenes CICC 21633, in which the diameter of inhibition zone was 12.83 ± 0.62 mm, 15.08 ± 0.31 mm, 6.75 ± 0.20 mm, respectively, compared with lactic acid bacteria N1, N2, M13, M21, M31, and M37. According to amplification of 16S rRNA gene and identification of phylogenetic tree, this strain had a 1,450 bp sequence and 100% identity to the L. plantarum strain. Based on the influence of different protease treatments, such as pepsin, trypsin, papain, and proteinase K on the antimicrobial activity, this antimicrobial substance was considered to be a natural protein. Using bacteriocin produced by this strain as study object of this experiment, it had been extracted from ammonium sulfate precipitation and different organic solvents. The results showed that ethyl acetate was selected as the optimal solution to crude extraction of bacteriocin after comparing ammonium sulfate precipitation method and organic solvent extraction method, such as n-butanol, n-hexane, dichloromethane, trichloromethane, in which the diameter of the inhibition zones was above 28 mm. Results also showed the inhibition spectrum of the obtained bacteriocin had a broad spectrum of inhibition which could inhibit Gram-positive, Gramnegative, yeast. Especially, it could effectively inhibit S. aureus ATCC 25923, Bacillus subtilis CICC 10002, Bacillus anthracis CICC 20443, E. coli JM109 ATCC 67387, and Salmonella CMCC 541, and the zone diameter of inhibition has reached more than 28 mm. Moreover, it had a good thermal stability which antibacterial activity was retained 70.58% after treatment at 121°C for 30 min, and pH-stability was between pH 2.0-9.0. These results suggested bacteriocin produced by L. plantarum zrx03 had potential application prospects in food preservation. K E Y W O R D Santimicrobial stability, bacteriocin, Lactobacillus plantarum zrx03, purification | 2215 LEI Et aL.

Partial characterization of probiotic lactic acid bacteria isolated from Chinese dairy products

“…plantarum against Staphylococcus aureus, Salmonella typhimurium, Escherichia coli O157:H7 and Listeria monocytogenes. [33,34] While there are some reports describing LAB bacteriocin activity against Gram-negative foodborne pathogens, [35] these peptides are more often active against Gram-positive pathogens, such as Listeria monocytogenes. [36] More studies are required to determine the antimicrobial compounds produced by these three LAB isolates, but the lack of antimicrobial activity for CFS from isolate E41, which had a similar pH to the others, suggests that the production of organic acid alone is not responsible for the broad-spectrum activity.…”

Bioprospecting Antimicrobials from Lactiplantibacillus plantarum: Key Factors Underlying Its Probiotic Action

“…Plantaricins produced from L. plantarum strains isolated from various niches also inhibited Bacillus spp. ( B. subtilis and B. anthracis ) [ 134 , 135 , 136 , 137 ], Shigella spp. [ 59 , 121 , 136 , 137 , 138 ], Micrococcus luteus [ 59 , 122 , 135 , 136 , 137 , 139 , 140 ], Vibrio parahaemolyticus [ 122 , 139 , 141 ], as well as Clostridium spp.…”

Simultaneous Production of Multiple Antimicrobial Compounds by Bacillus velezensis ML122-2 Isolated From Assam Tea Leaf [Camellia sinensis var. assamica (J.W.Mast.) Kitam.]

“…Cell-Free Supernatant Partial purification of surfactin was achieved by organic solvent extraction according to the protocol described by Lei et al (2020) with modifications as follows. Strain ML122-2 was cultured in TSB and incubated at 37°C, on a rotating platform at 150 rpm for 48 h before centrifugation at 5,000 × g at 4°C for 15 min.…”