Characterization and Evaluation of Antimicrobial Activity of Bacteriocins from Lactobacillus Curvatus and Pediococcus Pentosaceus

Abstract

Lactobacillus curvatus M3 and Pediococcus pentosaceus N2, isolated from fermented beef and infant faeces, respectively, exhibited antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis, Escherichia coli ATCC25922, Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa and Salmonella typhi. The activity was not due to H2O2 as similar inhibition was obtained by supernatants produced under aerobic or anaerobic growth conditions. The active ingredients were identified as bacteriocins of molecular mass of 3-4 kDa. The two bacteriocins were sensitive to proteinase-k and pepsin but were not affected by α-amylase, and experienced little reduction in activity on heating to 100˚C for 30min but were destroyed by autoclaving. Both bacteriocins exhibited highest inhibitory activity at pH 5.0. The bacteriocin from Lb. curvatus M3 was bactericidal while that from N2 was bacteriostatic to Staph. aureus. Kinetics of growth and bacteriocin production showed that maximal inhibitory activity coincided with the phase of optimal growth and with a drop in the pH of the growth medium to 4.2-4.5. Citation: Elyass ME, Altayar MA, Mahdi AA, Abdelrawaf SS, Shigidi MT, et al. (2015) Keywords: Lactobacillus curvatus, Pediococcus pentosaceus, Bacteriocins Characterization and Evaluation of Antimicrobial Activity of Bacteriocins from Lactobacillus Curvatus and Pediococcus Pentosaceus. J Infect Non Infect Dis 1: 001.• examined for Gram reaction, catalase production, cell morphology using phase contrast microscopy, gas production from glucose, hydrolysis of arginine, growth at pH 4.4 and 9.6, salt tolerance and growth at 10°C and 45°C.Gas production from glucose was determined in modified MRS broth containing inverted Durham tubes with diammonium citrate replaced by ammonium sulphate [13]. Glucose was sterilized separately (115°C for 10min) and was aseptically added to the medium. Hydrolysis of arginine was tested in MRS broth without glucose or meat extract but containing 0.3% arginine and 0.2% sodium citrate instead of ammonium citrate. Ammonia was detected using Nessler's reagent [14]. Growth at pH 4.4 and 9.6 was tested in MRS broth adjusted to these pH values using 1N HCl. Salt tolerance was tested in MRS broth supplemented with 6.5% NaCl. Growth at different temperatures was observed in MRS broth after incubation for 3 days at 15°C and 45°C.Ultimately, the two isolates were identified to specific level through biochemical profiling using the KB009 HiCarbohydrate identification kit (HiMedia Laboratories, Mumbai, India), which makes use of the patterns of utilization of 35 sugars. Screening for antagonistic activityThe antagonistic activities of the two isolates against four indicator bacteria (Staphylococcus aureus ATCC43306, Bacillus subtilis NCTC8236, Enterococcus faecalis ATCC10541 and Escherichia coli ATCC25922) were initially screened by the direct spot-on-lawn method [15] which was afterwards confirmed by the agar-well diffusion method [16].In the spot-on-lawn method, aliquots ...

Characterisation and action mode of Gluconacin, a bacteriocin with antimicrobial activity against Xanthomonas albilineans

“…Another important characteristic observed in our study was the stability of Gluconacin at acid pH levels and at high temperatures, even after submitting the peptide to autoclave conditions (121 C/115 kPa for 15 min). The stability of bacteriocins is crucial for their application, and although thermostability is well reported (Ansari, Zohra, Tarar, Qader, & Aman, 2018;Elyass, Mahdi, & Attitalla, 2015), it is reduced when there is the retention of activity in autoclaving conditions, as presented by Gluconacin. Other studies have also reported this characteristic in several bacteriocins (Ibrahim, Siddiqui, Aman, Qader, & Ansari, 2020;Qiao et al, 2020;Yi, Qi, Hong, Deng, & Zeng, 2020).…”

Isolation and Characterization of Bacteriocin Producing <em>Enterococcus species </em>from Ethiopian Traditional Fermented Food and Beverages

“…The mixture was centrifuged for 10 minutes, evaporated at 45 ºC, and re-suspended in saline (50ml, 9g/L). The partially purified crude bacteriocins were used to determine their characteristics and antagonistic activities against foodborne pathogens (Elyass et al, 2015).…”