Algae Chlorella vulgaris as a factor conditioning the survival of Lactobacillus spp. in adverse environmental conditions

This paper presents the impact of selected adverse environmental conditions of the human gastrointestinal tract on the survival of Lactobacillus spp. strains in the presence of the algae Chlorella vulgaris. The tested strains of Lactobacillus brevis (ŁOCK 0944, 0980, 0992, and MG451814) demonstrated high survival rates in bile salts (0.4% and 2.0%) and phenol (0.4%). The largest decrease in the number of lactic acid bacteria was observed in a low-pH solution. Moreover, the addition of Chlorella vulgaris to the growth environment of the tested bacteria increased their survival rates in the presence of bile salts and for 24 h when 0.4% (v/v) phenol was in the environment. The protective effect of algae at low pH is a strain-dependent feature. Furthermore, to increase the survival of the Lactobacillus brevis in this study, it was beneficial to add algae to the bacterial culture after 24 h. The survival rate of Lactobacillus spp. grown in the presence of Chlorella vulgaris in adverse environmental conditions supports the use of algae as a component of fermented food products. •Chlorella vulgaris increased the survival of Lactobacillus spp. in bile salts.•The protective effect of algae at low pH was a strain feature.•Chlorella vulgaris protected tested LAB during 24 h of incubation with 0.4% phenol.•Chlorella vulgaris may be used in fermented dietary products.