Metabolite profiling from the fermentation of marine-derived extracts by Lactobacillus acidophilus LB

Lactobacillus acidophilus LB is a probiotic strain with the ability to produce valuable bioactive metabolites through fermentation. Sustainable biomass sources such as Spirulina platensis, Ulva reticulata, and Caulerpa lentillifera, which can also be obtained from agricultural or aquacultural by-products, offer a promising alternative for microbial cultivation, but their effects on the metabolic profile of L. acidophilus LB are still unclear.

The study utilized L. acidophilus LB (GenBank accession OK398226) cultivated in media containing Spirulina platensis, Ulva reticulata, and Caulerpa lentillifera extracts. High-resolution mass spectrometry (liquid chromatography-high resolution mass spectrometry-quadrupole-time-of-flight, LC-HRMS QTOF) was employed for compound profiling. Principal component analysis (PCA) and Pearson correlation were used to analyze metabolic variations across different culture conditions. The Kruskal-Wallis test assessed statistical differences in metabolite concentrations.

Methyl lucidenate Q and 6-Gingerol were the most abundant bioactive compounds detected across samples. PCA revealed that L. acidophilus LB in media supplemented with different preparations of Spirulina platensis, Ulva reticulata, and Caulerpa lentillifera was associated with distinct differences in metabolite profiles, leading to clustering patterns. K-means clustering identified three metabolomic groups, with the pellet obtained from L. acidophilus LB cultured in medium supplemented with U. reticulata seaweed showing a unique chemical profile. Pearson correlation analysis suggested possible biochemical interactions among metabolites, with Auraptenol and Daturametelin B exhibiting a strong positive correlation (r = 0.99). The absence of Methyl lucidenate Q in this sample indicates potential enzymatic degradation or metabolic inhibition.

This study highlights the impact of L. acidophilus LB on metabolite diversity in substrate-driven fermentation systems. The findings suggest microbial interactions modulate metabolite patterns in the fermented supernatants, potentially enhancing pharmacological properties. Future research should focus on optimizing culture conditions to maximize yield and functional validation of identified compounds for therapeutic applications. These insights contribute to the broader field of natural product discovery and marine biotechnology.