Pensom Jumriangrit. Characterization and purification of a bacteriocin produced by Lactobacillus plantarum PMU33 strain from fermented fish products . Master's Degree(Biochemistry). Mahidol University. : Mahidol University, 2004.
Characterization and purification of a bacteriocin produced by Lactobacillus plantarum PMU33 strain from fermented fish products
การศึกษาคุณสมบัติและการทำให้บริสุทธิ์ของสารยับยั้งแบคเทอรอโอซินจาก Lactobacillus plantarum สายพันธุ์ PMU33 แยกจากผลิตภัณฑ์อาหารหมักจากปลา
Abstract:
Lactic acid bacteria play an important role in the fermentation process. They can
produce many kinds of substances to preserve food by adding texture, aroma, and taste
to the products. Studying of bacteriocin-producing strains may be useful to improve
microbial safety in fermented food products. A total of 59,509 lactic acid bacteria
isolates from ten fermented fish products were screened for bacteriocin activity using a
direct plating method. Of these 0.27 % were detected. One isolate from som-fak (one
type of fish products) was found to produce a bacteriocin and identified as
Lactobacillus plantarum PMU33 strain. This strain produces a stable secretory
bacteriocin that is inhibitory not only to the closely related species but also to many
food-borne pathogenic bacteria including Enterococcus faecalis, Staphylococcus
aureus and some species of Listeria. This bacteriocin is the peptide as it is inactivated
by four proteases. It is heat stable and active over a wide pH range (2-10). This
bacteriocin was purified to homogeneity through a three step process: hydrophobic
adsorption (Amberlite XAD-16), cation exchange chromatography, and reverse phase
chromatography. 10 residues of the N-terminal amino acid sequence of this purified
bactericin showed a sequence similarity to one peptide of the two-peptide lantibiotic
plantaricin W alpha (Plwα), a reported bacteriocin. The bacteriocin produced by L.
plantarum PMU33 was confirmed to be plantaricin W by polymerase chain reaction
using specific primers from the structural gene of plantaricin W. The amplified DNA
fragment of about 591 base pairs was sequenced and shown to encode two peptides
that are identical to the two- peptides (plwα, plwβ) lantibiotic plantaricin W.