Identification and production of a bacteriocin from Enterococcus mundtii QU 2 isolated from soybean

Abstract

Aims: Identification of the bacteriocin produced by Enterococcus mundtii QU 2 newly isolated from soybean and fermentative production of the bacteriocin. Methods and Results: The bacteriocin produced by Ent. mundtii QU 2 inhibited the growth of various indicator strains, including Enterococcus, Lactobacillus, Leuconostoc, Pediococcus and Listeria. The bacteriocin activity was stable at wide pH range and against heat treatment, but completely abolished by proteolytic enzymes. The bacteriocin was purified from the culture supernatant by the three-step chromatographic procedure. Mass spectrometry, amino acid sequencing and DNA sequencing revealed that the bacteriocin was similar to class IIa bacteriocins produced by other Ent. mundtii strains. The bacteriocin production decreased in the absence of glucose, nitrogen sources, or Tween 80 in MRS medium. Additionally, it was strongly suppressed by addition of Ca 2+ (CaCO 3 or CaCl 2 ). In pH-controlled fermentations, the highest bacteriocin production was achieved at pH 6AE0, whereas the highest cell growth was obtained at pH 7AE0. Conclusions: Ent. mundtii QU 2 produced a class IIa bacteriocin. Some growth factors (e.g. Ca 2+ and pH) influenced the bacteriocin production. Significance and Impact of the Study: A new soybean isolate, Ent. mundtii QU 2 was found to be a class IIa bacteriocin producer. Factors influencing the bacteriocin production described herein are valuable for applications of the bacteriocins from Ent. mundtii strains.

Production, stability, gene sequencing and in situ anti-Listeria activity of mundticin KS expressed by three Enterococcus mundtii strains

“…The structural genes were analyzed using primers mapping on the nucleotide sequence of E. mundtii bacteriocin-coding genes. All three strains were positive for the presence of a fragment of the known mundticin KS (Kawamoto et al, 2002), CRL35 (Saavedra et al, 2004), QU2 (Zendo et al, 2005) and MunL (Feng et al, 2009), while only E. mundtii WFE20 was negative when analyzed with the primers designed for the biosynthetic cluster for enterocin CRL35. The nucleotide sequences of the three 381 bp DNA fragments obtained after the first PCR amplification showed only five nucleotides different among the three strains.…”

“…Genomic DNA from E. mundtii WFE3, WFE20 and WFE31 were used as templates for amplification with the primer pair Mnt-1F (5 0 -TGAGA-GAAGGTTTAAGTTTTGAAGAA-3 0 )/Mnt-1R (5 0 -TCCACTGAAATCCAT-GAATGA-3 0 ) mapping upstream of the coding sequence of known bacteriocins KS (Kawamoto et al, 2002), CRL35 (Saavedra, Minahk, de Ruiz Holgado, & Sesma, 2004), QU2 (Zendo et al, 2005) and MunL (Feng, Guron, Churey, & Worobo, 2009), applying the conditions described by Zendo et al (2005). DNA from E. mundtii PON10063 was used as negative control in PCRs.…”

Characterization and identification of weissellicin Y and weissellicin M, novel bacteriocins produced by Weissella hellenica QU 13

“…The obtained pattern was analysed using the apiweb software (bioMérieux) and compared to the previous report (Collins et al 1993). A partial 16S rDNA region of strain QU 13, corresponding to positions 8-1510 of E. coli 16S rDNA, was analysed as described previously (Zendo et al 2005).…”

Efecto de las condiciones de crecimiento y composición del medio de cultivo sobre la producción de bacteriocina de Enterococcus mundtii Tw56

“…Este resultado no está de acuerdo con los exhibidos en trabajos previos que muestran sólo una disminución marcada del nivel de actividad a la temperatura citada. (Zendo et al, 2005;Settanni et al, 2008;Kanmani et al, 2011) Se realizaron, en forma adicional, ensayos a más bajas temperaturas y se detectó tanto crecimiento como actividad hasta 8 °C (datos no mostrados).…”