Biotechnology production of pediocin: optimization of yield and biological effects on cells of the immune system

Abstract

Bacteriocins are peptides produced by various species of microorganisms and exhibit antimicrobial properties. Those that are produced by lactic acid bacteria have a great interest in the food and pharmaceutical industry. Some studies have demonstrated the ability of inulin and sucrose as carbon alternative sources, as well as promoting the growth of lactic acid bacteria. In the inulin application, it becomes increasingly important to study the interactions between these lactic acid bacteria and fibers considered prebiotic during the fermentation process in order to increase the production of high-value biomolecules such as bacteriocins. In this context, this project aims to study the variables that influence the production of pediocin by Pediococcus pentosaceus in metabolic shaker and 3-liter bioreactor. Studies will be conducted with the aid of experimental design, by the influence of relevant variables in the production of this peptide, such as pH, substrate concentration (sucrose and inulin), stirring and temperature conduction of fermentation process. During cultivation in metabolic shaker, samples will be collected in intervals of 6 hours for pH analysis, sugar concentration (glucose and fructose), biomass organic acids (lactic and malic acids) and pediocin activity against microorganisms bioindicators. Cultures in bioreactor, which aims to establish effective conditions for an industrial application, will be made based on experimental design DCCR (Delineation Central Composite Rotational) for 2 factors: agitation (50, 100 and 150 rpm) and aeration (0.5, 1.0 and 1.5 vvm), expressed by the volumetric oxygen transfer coefficient (kLa). In this case, will be used the culture medium that leading to the maximization of the response assays (antimicrobial activity and pediocin production) obtained in metabolic shaker. In a bioreactor, the cultivation time, initially scheduled for 48 hours, may be changed after the initial experiment, since it will be evaluated in which cultivation phase the microorganism will be found. At this process stage, samples will be collected in intervals of 6 hours for lactic and malic acids concentration analysis, cell concentration, sugars (glucose and fructose) and pediocin activity. Both, the pH and the dissolved oxygen level, will be monitored in real time by the respective probes coupled to the bioreactor. These tests will be carried out to verify the pediocin biological action in immune cells. (AU)