Development of a high throughput approach to investigate nitrogen metabolism in Lactic Acid Bacteria

Lactic Acid Bacteria (LAB) are a heterogeneous group of Gram-positive bacteria, catalase-negative, non-spore-forming, low-GC, either rod-shaped or spherical. The traditional use of many LAB as starter cultures in food and dairy fermentations led to their widespread in human consumption. The knowledge of LAB nitrogen metabolism, including their nutritional nitrogen requirements, constitutes a tool that could help the researchers and professionals of alimentary industries to produce foods with optimal qualities. Phenotype Microarray (PM) analysis, which is a high throughput method for microbial characterization, has been applied to the chemical sensitivity and carbon metabolism analysis of LAB. Nevertheless, such approach failed when nitrogen metabolism was investigated. Consequently, the aim of the present research is to define an efficient protocol for analysing LAB nitrogen metabolism using PM, evaluating appropriate tetrazolium dye, used as a reporter of metabolic activity, carbon sources, and buffer conditions. The results obtained will be showed and discussed.