Investigation of Shelf Life of Potency and Activity of the Lactobacilli Produced Bacteriocins Through Their Exposure to Various Physicochemical Stress Factors.

Three Lactobacilli strains, Lactobacillus casei NCIMB 11970, Lactobacillus plantarum NCIMB 8014, Lactobacillus lactis NCIMB 8586 have been used for the production of bacteriocins. Though, their production phase, their biochemical nature, their mode of activity even their genetic structure have been widely investigated, there are hardly any studies investigating their potency and activity in depth of time, in other words their shelf life under several physicochemical conditions that may occur during their production in large scale. As such, the effect of several factors influencing the activity and the potency of bacteriocins when produced in large scale was examined as due to bacteriocins peptide nature degradation or denaturation might occur, under extreme physicochemical conditions. During scale-up process, differences between the output data may occur, such as concerning biomass, metabolic by-products and limiting substrate concentrations. These may affect negatively the activity and the potency of the bacteriocins. For investigating these effects and minimizing them, numerous studies were conducted, which were related to the exact phase of the production of these substances, the effect of dilution and temperature changes. These studies could be used in order to minimize the scaling-up effect when decided to produce these peptides in large scale.