Characterization of a New Bacteriocin from Lactobacillus plantarum LE5 and LE27 Isolated from Ensiled Corn

Abstract

Bacteriocins are low molecular peptides with antimicrobial activity, which are of great interest as food bio-preservatives and for treating diseases caused by pathogenic bacteria. In this study, we present the characterization of bacteriocins produced by Lactobacillus plantarum LE5 and LE27 isolated from ensiled corn. Bacteriocins were purified through ammonium sulfate precipitation and double dialysis by using 12- and 1-kDa membranes. Bacteriocins showed activity against Listeria innocua, Listeria monocytogenes, and Enteroccocus faecalis. Molecular weight was estimated through Tricine-SDS-PAGE and overloading the gel onto Mueller-Hinton agar seeded with L. monocytogenes, showing an inhibition zone between 5 and 10 kDa. NanoLC-MS/MS analysis allowed the identification of UPF0291 protein (UniProtKB/Swiss-Prot Q88VI7), which is also presented in other lactic acid bacteria without assigned function. Ab initio modeling showed it has an α-helix-rich structure and a large positive-charged region. Bacteriocins were stable between 4 and 121 °C and pH 2 and 12, and the activity was inhibited by SDS and proteases. Mode of action assay suggests that the bacteriocin causes of target microorganism. Taken together, these results describe a possible new class IIa bacteriocin produced by L. plantarum, which has a wide stability to physicochemical conditions, and that could be used as an alternative for the control of foodborne diseases.

Production and Characterization of Bacteriocin Produced by Lactobacillus Viridescence(NICM 2167)

“…1). Similar reports were observed in case of bacteriocin production from Lactobacillus plantarum where optimum period was found to be at 48 h, in contrast production of bacteriocin form Bacillus subtilisR75 required 72 h of incubation (Sharma et al 2011;Amortegui et al 2014). In pH optimization studies, the concentration of protein was found to be highest at pH 7, whereas considerable decrease was observed at both acidic as well as alkaline pH (Fig.…”

“…8). Similar results were shown in case of bacteriocins produced by Bacillus Subtilis R75 as well as LactobacillusplantarumLE5 and LE7 (Sharma et al 2011;Amortegui et al 2014).Purified bacteriocin in this study even had shown activity after treatment at 121⁰C which opens an avenue for its use in such food products which needs to be operated at high temperatures.It can also show the activity against food pathogens which are heat resistant and hence could be exploited as a potent source of bacteriocin. …”

“…(Fig. 3) Similar results were observed in case various other microorganisms where bacteriocin production was taken at 37°C temperature (Sharma et al 2011;Amortegui et al 2014). Bacteriocin with wide spectrum of antimicrobial activity was further subjected to purification process.…”

“…Most of the reports of bacteriocin production from Lactobacillus showed its production at acidic to slightly neutral range of pH, on the contrary our study stated highest production at neutral range of pH (Deraz et al 2005;Amortegui et al 2014). While in case of temperature optimization studies, better results were found at 37°C having highest protein content as well as cell biomasssuggestingit as an optimum temperature for the production of bacteriocin.…”

“…7). Similarly significant activity at pH 6 and 7 was shown in case of bacteriocin produced from Bacillus subtilis R75 (Sharma et al 2011), whereas bacteriocin from LactobacillusplantarumLE5 and LE7 was found to be active at wide range of pH values ranging from 2 to 12 (Amortegui et al 2014).In temperature stability studies it was found that purified bacteriocin was stable at wide range of temperatures (Fig. 8).…”