Bioenrichment of conjugated linoleic acid in oil-in-water (O/W) emulsion by Niubie as a natural biocatalyst

Conjugated linoleic acid (CLA) exhibits diverse physiological functions mainly attributed to its two predominant isomers. However, it is naturally scarce, and nearly absent in vegetable oils. Herein, Niubie, a traditional food ingredient from Guizhou, was evaluated as a natural biocatalyst to assess its capacity for CLA enrichment and optimize its application in vegetable oil emulsion system. Metagenomic analysis of microbial community composition and functional gene profiles identified the slaughterhouse-sourced sample (Group Q) as exhibiting the highest relative abundance of CLA-producing bacteria, including Butyrivibrio , along with the greatest predicted abundance of linoleic acid isomerase (LAI)-encoding genes. Dominant microbial taxa were identified, e.g. Prevotella , Butyrivibrio , Bacteroides , and Succiniclasticum , with linoleic acid metabolism identified as the primary functional pathway. Based on these microbial and functional insights, the biocatalytic process was optimized by constructing a Tween 80-stabilized O/W emulsion system. This optimized system achieved a maximum total CLA conversion yield of 10.53 mg/g oil, with cis-9, trans-11-CLA as the predominant isomer. These results indicate that Niubie, which contains CLA-producing microbiota and LAI-associated functional capacity, can be effectively processed within an engineered emulsion microenvironment, yielding substantial CLA bioenrichment. This study provides a theoretical foundation for the high-value utilization of Niubie and supports exploring novel CLA sources.