Impact of stress conditions on the growth of Lactobacillus acidophilus IBB 801 and production of acidophilin 801

The influence of different stress conditions, such as low and high temperatures, the presence of salt or ethanol in the medium, on the growth of Lactobacillus acidophilus IBB801 and the production of acidophilin 801 was investigated in this study. The strain was able to grow at up at to 47°C, while higher temperatures were lethal. A slow growth was detected at 24°C, starting after 24 h of incubation, and the strain was able to survive at 10°C for more than 48 h of incubation. The protein profiles revealed by one dimensional SDS-PAGE showed at least four overexpressed and two repressed bands at low temperatures (10°C and 24°C) compared with the profiles at 37°C and 42°C. The bacteriocin activity was the highest when the producing strain was grown at optimum temperature. However, at 10°C, the inhibitory activity showed a slight increase compared with the one reached at 24°C and 47°C. The same increase in activity was observed in the presence of low amounts of salt (5 to 10 g/L). Higher concentrations of salt or ethanol addition to the growth medium had a negative effect on acidophilin biosynthesis.