Optimization of Bacteriocin Production by Batch Fermentation of Lactobacillus plantarum LPCO10

Abstract

Optimization of bacteriocin production by Lactobacillus plantarum LPCO10 was explored by an integral statistical approach. In a prospective series of experiments, glucose and NaCl concentrations in the culture medium, inoculum size, aeration of the culture, and growth temperature were statistically combined using an experimental 2 3 5-2 fractional factorial two-level design and tested for their influence on maximal bacteriocin production by L. plantarum LPCO10. After the values for the less-influential variables were fixed, NaCl concentration, inoculum size, and temperature were selected to study their optimal relationship for maximal bacteriocin production. This was achieved by a new experimental 3 2 3-1 fractional factorial three-level design which was subsequently used to build response surfaces and analyzed for both linear and quadratic effects. Results obtained indicated that the best conditions for bacteriocin production were shown with temperatures ranging from 22 to 27°C, salt concentration from 2.3 to 2.5%, and L. plantarum LPCO10 inoculum size ranging from 10 7.3 to 10 7.4 CFU/ml, fixing the initial glucose concentration at 2%, with no aeration of the culture. Under these optimal conditions, about 3.2 ؋ 10 4 times more bacteriocin per liter of culture medium was obtained than that used to initially purify plantaricin S from L. plantarum LPCO10 to homogeneity. These results indicated the importance of this study in obtaining maximal production of bacteriocins from L. plantarum LPCO10 so that bacteriocins can be used as preservatives in canned foods.Lactic acid bacteria (LAB) are widely used as starter cultures in dairy, meat, and vegetable fermentations (1, 7, 36). One major reason for their wide use is the wide range of antimicrobial substances that they are able to produce which efficiently contribute to the preservation of the fermented products (13,15,31). Of these antimicrobial substances, bacteriocins are one of the most promising natural food preservatives produced by LAB (10,12,26,33,34). This preservation potential could be achieved either by using a bacteriocin-producing starter culture or by applying the bacteriocin itself as a food additive. The latter will necessarily require optimization of their production, for this is dependent on multiple factors which are usually strain specific (9, 39).In the past, several studies have pursued this goal for a number of different bacteriocins. They have generally focused on the effects of pH, temperature, composition of the culture medium, and general microbial growth conditions (in vitro as well as in natural fermentations) on maximal bacteriocin production (2,4,6,8,11,14,24,25,(28)(29)(30)(38)(39)(40). However, although some of these studies claim validation by a statistical test, usually variance analysis, the combination of variables and their values and limits are arbitrarily chosen, based mainly on subjective personal experience. Thus, usually no previous prospective experimental design is performed to optimize the information that can be gained ...

Effect of Medium Composition and Culture Condition on the Production of Bacteriocin-Like Inhibitory Substances (BLIS) byLactobacillus ParacaseiLA07, a Strain Isolated from Budu

“…this preservation technique could be employed either by using a bacteriocin-producing starter culture or by applying the purified bacteriocin as a food additive. the latter will necessarily require optimization of their production, which is essentially dependent on multiple strain-specific factors (15).…”

Bacteriocin production by Lactobacillus plantarum AMA-K isolated from Amasi, a Zimbabwean fermented milk product and study of the adsorption of bacteriocin AMA-K to Listeria sp.

“…Bacteriocin production changes dramatically upon altering of environmental conditions and optimum production may require a specific combination of environmental parameters (22). Little is known about the interactions these factors have on the production of a bacteriocin, especially in a complex food environment.…”

Production of plantaricin NC8 by Lactobacillus plantarum NC8 is induced in the presence of different types of gram-positive bacteria

“…Finally, in order to investigate whether or not PLNC8 itself was involved in the 11 autoinducing activity, the purified peptides PLNC8α and PLNC8β generated from PLNC8 12 by C 2 -C 18 reverse-phase chromatography (Maldonado et al 2003) The influence of pH (Ahn and Stiles 1990;Barefoot et al 1994b;Jiménez-Díaz et al 1993;5 Kaiser and Montville 1993;Kleerebezem et al 1997), temperature (Diep et al 2000;Leal-6 Sánchez et al 2002;Mørtvedt-Abildgaard et al 1995;Tichaczeck et al 1992), and growth 7 conditions (Biswas et al 1991;de Vuyst et al 1996;Gutowski-Ecked et al 1994;Jiménez-8 Díaz et al 1993;Leal-Sánchez et al 2002), previously described as enhancers of 9 bacteriocin production by LAB, was studied. None of these factors appeared to promote 10 production of PLNC8 by L. plantarum NC8 growing alone.…”