Pediococci are lactic acid bacteria (LAB) which have been used for centuries in the production of traditional fermented foods. There fermentative abilities were explored by the modern food processing industry in use of pediococci as starter cultures, enabling the production of fermented foods with distinct characteristics. Furthermore, some pediococci strains can produce bacteriocins and other antimicrobial metabolites (AMM), such as pediocins, which are increasingly being explored as bio-preservatives in various food matrices. Due to their versatility and inhibitory spectrum, pediococci bacteriocins and AMM are being extensively researched not only in the food industry, but also in veterinary and human medicine. Some of the pediococci were evaluated as potential probiotics with different beneficial areas of application associated with human and other animals' health. The main taxonomic characteristics of pediococci species are presented here, as well as and their potential roles and applications as starter cultures, as bio-preservatives and as probiotic candidates.
The aim of this project was to screen for bacteriocinogenic Bacillus strains with activity versus Staphylococcus spp. with future application in formulation of pharmaceutical antimicrobial preparations. Putative bacteriocinogenic strains, isolated and pre-identified as Bacillus spp. were selected for future study and differentiated based on repPCR and identified as Bacillus subtilis for strains ST826CD and ST829CD, Bacillus subtilis subsp. stercoris for strain ST794CD, Bacillus subtilis subsp. spizizenii for strain ST824CD, Bacillus velezensis for strain ST796CD, and Bacillus tequilensis for strain ST790CD. Selected strains were evaluated regarding their safety/virulence, beneficial properties, and potential production of antimicrobials based on biomolecular and physiological approves. Expressed bacteriocins were characterized regarding their proteinaceous nature, stability at different levels of pH, temperatures, and the presence of common chemicals applied in bacterial cultivation and bacteriocin purification. Dynamic of bacterial growth, acidification, and cumulation of produced bacteriocins and some aspects of the bacteriocins mode of action were evaluated. Based on obtained results, isolation and application of expressed antimicrobials can be realistic scenario for treatment of some staphylococcal associated infections. Appropriate biotechnological approaches need to be developed for cost effective production, isolation, and purification of expressed antimicrobials by studied Bacillus strains.