Fermentation dynamics of bile salt hydrolase production in Heyndrickxia coagulans ATCC 7050 and Lactiplantibacillus plantarum ATCC 10012: Addressing ninhydrin assay limitations with a novel HPTLC-MS method.

Bile salt hydrolase (BSH), a pivotal enzyme in cholesterol management, holds significant promise in both human and animal subjects. This study investigated the effect of fermentation dynamics in Heyndrickxia coagulans ATCC 7050 and Lactiplantibacillus plantarum ATCC 10012 to enhance BSH production. Cultivation of cultures in MRS and M17 media revealed that MRS medium enhanced BSH production by 235.98 % in H. coagulans ATCC 7050 and 147.37 % in L. plantarum ATCC 10012, compared to M 17 medium. Additionally, varying oxygen concentration levels indicated that H. coagulans ATCC 7050 exhibited its minimum doubling time of 79.8 ± 0.64 min in anaerobic conditions, whereas L.plantarum ATCC 10012 demonstrated its minimum doubling time of 85.5 ± 1.2 min under microaerophilic conditions. However, their highest BSH activity was observed during the stationary phase under anaerobic conditions, yielding 17.14 ± 0.78 U/mL by H. coagulans ATCC 7050 and 19.04 ± 0.81 U/mL by L.plantarum ATCC 10012. Furthermore, it was observed that both organisms did not retain BSH within their cells. BSH activity was assessed using ninhydrin assay that detected free taurine liberated from sodium taurocholate. However, ninhydrin can yield false-positive results owing to its interaction with other free amino acids. To subjugate this limitation, the study introduced a novel and sensitive HPTLC-MS method capable of accurately detecting taurine. By comprehending fermentation dynamics and selecting appropriate conditions, BSH production increased 2.1-fold in both organisms. These findings illuminate critical insights, offering a pathway for novel strategies to enhance the BSH-producing capabilities of these LAB strains.