Design of a culture medium for the scaling-up of the production of the probiotic strain Lactobacillus salivarius A3iob

VINDEROLA, G.; PIMENTEL, J.; SORIA, M. CECILIA; AUDISIO, M. CARINA

Simposio; V Simposio Internacional de Bacterias Lácticas (V SIBAL); 2016

The development of appropriate technologies for the production of probiotic cultures is a key research area for their industrial production. Since biomass production in commercial culture media is expensive to be performed at large scale, looking for economical ingredients is mandatory. In this sense, food industry by-products, such as molasses (a syrup obtained from the residue of sugar cane processing), cheese whey or different flours have been proposed as alternative ingredients. The aim of this work was to formulate an economical culture medium for Lactobacillus salivarius A3iob using by-products of the food industry. L. salivarius A3iob was activated in MRS broth (37°C, 16 h). Before use, the active culture was centrifuged and washed twice with phosphate buffered saline solution. For medium formulation, a basal media (E) was prepared containing cheese whey powder (1.5% w/v), molasses (1% w/v), Tween 80 (0.1%), MgSO4 (0.02%) and MnSO4 (0.005%). As N source, the effect of the addition of yeast extract (0.5 %) (Britania) or commercial soy flour (0.5%) (from the production of soy-oil) to E medium on biomass production was studied. Subsequently, cheese whey was assessed at different concentrations (1.5, 3, 5 or 7 % (w/v)). For these assays, batch cultures (5 mL) were incubated for 8 h at 37ºC, under microaerophilic conditions (extinction of a candle flame into a jar, O2 and CO2 pressure around 7 and 14%, respectively). Once N source and whey powder concentrations were selected, different molasses concentrations (1, 3, 5 or 7 % (w /v)) were assessed using growth curves (0, 4, 8, 18 and 24 h) on 100 mL of E media (37ºC, microaerophilic conditions). In all cases, MRS broth was used as control medium and the results were expressed as CFU/mL. The results of N source studies showed that yeast extract was more suitable than soy flour for the growth of L. salivarius A3iob. In relation to cheese whey concentration, 1.5% was enough to reach 108 CFU/mL, a value similar to that obtained in MRS broth (control). Finally, 3 % (w/v) molasses was adequate for the growth of L. salivarius A3iob with biomass yield equal or higher than MRS control (10^8-10^9 CFU/mL). The results indicate that E medium, reinforced with yeast extract (0.5 %), molasses (3 %) and whey powder (1.5 >%) would represent an economical alternative for the scaling up biomass production of L. salivarius A3iob