Screening of Lactobacillus strains for their ability to produce conjugated linoleic acid in milk and to adhere to the intestinal tract

Abstract

Conjugated linoleic acid (CLA) has been shown to provide beneficial effects on health; however, the amount consumed in food is far from that required for the desired effects. Thus, increasing the CLA content in dairy foods through milk fermentation with specific lactic acid bacteria (LAB) offers an interesting alternative. Moreover, some LAB may be able to adhere to the intestinal mucosa and produce CLA through endogenous synthesis. Therefore, the objective of this study was to screen LAB isolates for their ability to produce CLA in skim milk and in simulated gastrointestinal conditions. Additionally, the ability of selected CLA-producing LAB to adhere to the intestinal mucosa in a murine model was assessed. Results showed that of 13 strains of Lactobacillus tested, only 4 were able to produce CLA in skim milk supplemented with linoleic acid (13.44 ± 0.78 to 50.9 ± 0.26 µg/mL). Furthermore, these 4 Lactobacillus strains were able to survive and produce CLA in simulated gastrointestinal conditions and to adhere to the intestinal mucosa of Wistar rats after 7 d of oral inoculation with fluorescently labeled bacteria. Accordingly, these 4 Lactobacillus strains may be used to manufacture fermented dairy foods to increase CLA content, and consumption of these fermented milks may result in CLA produced endogenously by these LAB.

Lactic Acid Bacteria and Bifidobacteria with Potential to Design Natural Biofunctional Health-Promoting Dairy Foods

“…The two isomers that have been shown to have bioactive potential are cis -9, trans -11 ( c 9, t 11) and trans -10, cis -12 ( t 10, c 12). The health-promoting properties of CLA include anticarcinogenic, antiatherogenic, anti-inflammatory, and antidiabetic activity, as well as the ability to reduce body fat (Sosa-Castañeda et al, 2015). Although it is a native component of milk, the amount consumed in foods is far from that required in order to obtain desired beneficial effects.…”

Isolation, molecular characterization and screening of indigenous lactobacilli for their abilities to produce bioactive conjugated linoleic acid (CLA)

“…Recently, Terán et al (2015) examined 64 food-grade lactobacilli for CLA isomers production and revealed that only 04 L. plantarum strains were able to synthesize CLA isomers from LA which is lower than the 03 L. plantarum strains (HIF15, HIF64, HIF128) reported in present study. In another recent study Sosa-Castañeda et al (2015) assessed the CLA production abilities of 13 Lactobacillus strains out of which strain L. fermentum J20 produced more c9, t11 (42.63 ± 0.91 lg/ml) and t10, c12 (8.27 ± 0.64 lg/ml) CLA isomers then reported in present investigation. By contrary, the production of c9, t11(7.73 ± 0.52 lg/ml) isomer by another L. fermentum strain J23 is lower while that of t10, c12 (11.25 ± 0.51 lg/ml) is higher than L. fermentum strains reported here.…”

“…Therefore, microbial CLA uptake in humans is visualized as the most purposeful strategy. CLA producers have the ability to crosslink with adipocytes cell lines in vitro and gut epithelial cells in human and animal model (Sosa-Castañeda et al 2015). Moreover, in an in vitro study Dahiya and Puniya (2015) reported that CLA producing strains had good probiotic-to-functional attributes.…”

“…But it has been suggested that a LA detoxifying mechanism works behind it. Incorporation of LA into bacterial cell membrane changes the lipid bilayer chemistry, membrane potential and even intramembrane pathways (Sosa-Castañeda et al 2015); therefore for survival bacteria could have to detoxify the LA. Our major concern was to identify the high t10, c12 and t9, t11 CLA producer in addition to c9, t11 isomer.…”

“…However, the concentration of CLA present in foodstuffs is lower and depends upon feedstock and animal breed (Sosa-Castañeda et al 2015). Besides, in a majority of these products c9, t11 isomer accounts for[70% of total CLA (Lock and Bauman 2004).…”