Abstract
Fatty acid profiles are crucial for the functionality and viability of lactobacilli used in food applications. Tween 80™, a common culture media additive, is known to influence bacterial growth and composition. This study investigated how Tween 80™ supplementation impacts the fatty acid profiles of six mesophilic lactobacilli strains (Lacticaseibacillus spp., Limosilactobacillus spp., Lactiplantibacillus plantarum). Analysis of eleven strains revealed 29 distinct fatty acids. Tween 80™ supplementation significantly altered their fatty acid composition. Notably, there was a shift towards saturated fatty acids and changes within the unsaturated fatty acid profile. While some unsaturated fatty acids decreased, there was a concurrent rise in cyclic derivatives like lactobacillic acid (derived from vaccenic acid) and dihydrosterculic acid (derived from oleic acid). This suggests that despite the presence of Tween 80™ as an oleic acid source, lactobacilli prioritize the synthesis of these cyclic derivatives from precursor unsaturated fatty acids. Myristic acid and dihydrosterculic acid levels varied across strains. Interestingly, palmitic acid content increased, potentially reflecting enhanced incorporation of oleic acid from Tween 80™ into membranes. Conversely, cis-vaccenic acid levels consistently decreased across all strains. The observed fatty acid profiles differed from previous studies, likely due to a combination of factors including strain-specific variations and growth condition differences (media type, temperature, harvesting point). However, this study highlights the consistent impact of Tween 80™ on the fatty acid composition of lactobacilli, regardless of these variations. In conclusion, Tween 80™ significantly alters fatty acid profiles, influencing saturation levels and specific fatty acid proportions. This work reveals key factors, including stimulated synthesis of lactobacillic acid, competition for oleic acid incorporation, and strain-specific responses to myristic and dihydrosterculic acids. The consistent reduction in cis-vaccenic acid and the presence of cyclic derivatives warrant further investigation to elucidate their roles in response to Tween 80™ supplementation.