Sourdough lactic acid bacteria detoxification pathways and metabolism of trace elements

Some bacteria have been studied for their capacity in improving macro- and micronutrient bioavailability and for specific degradation pathways responsible for the detoxification of contaminated environments. The efficient reduction of metal is fundamental for detoxification processes and can be translated to food matrices where the huge enzymatic portfolio of autochthonous lactic acid bacteria (LAB) may be used in terms of bioremediation. By studying sourdough LAB we sought to analyse functional differences in species-specific enzymatic activities related to trace element metabolism. The genome-based knowledge resulting from the complete sequencing and annotation of strains included in our biobank (Fructilactobacillus sanfranciscensis, Furfurilactobacillus rossiae and Lactiplantibacillus plantarum), allowed the comparison of their enzymatic portfolio. To test viability, robustness and resilience of these sourdough species in presence of trace elements, real time qPCR gene profiles of 44 key genes were obtained before and after supplementation with iron, arsenate, copper, cadmium, manganese, phosphate, and nitrate. In order to measure LAB viability and trace spatial chemotactic response to metals, culture media were supplemented with trace elements at different concentrations. Additionally, evidence of LAB changes in mineral absorption and relative metal metabolisms were detected by using spectrophotometric assays where the recorded absorbance profiles were monitored and compared. Finally, our multi-omics approach revealed differences in the profiles of genes and transcripts fundamental for the metabolism of trace elements and consequently impacting viability, resilience and robustness of key player LAB species.