Metabolic and proteomic adaptation of Lactobacillus rhamnosus strains during growth under cheese‐like environmental conditions compared to de Man, Rogosa, and Sharpe medium

Abstract

The aim of this study was to demonstrate the metabolic and proteomic adaptation of Lactobacillus rhamnosus strains, which were isolated at different stages of Parmigiano Reggiano cheese ripening. Compared to de Man, Rogosa, and Sharpe (MRS) broth, cultivation under cheese-like conditions (cheese broth, CB) increased the number of free amino acids used as carbon sources. Compared with growth on MRS or pasteurized and microfiltrated milk, all strains cultivated in CB showed a low synthesis of d,l-lactic acid and elevated levels of acetic acid. The proteomic maps of the five representative strains, showing different metabolic traits, were comparatively determined after growth on MRS and CB media. The amount of intracellular and cell-associated proteins was affected by culture conditions and diversity between strains, depending on their time of isolation. Protein spots showing decreased (62 spots) or increased (59 spot) amounts during growth on CB were identified using MALDI-TOF-MS/MS or LC-nano-ESI-MS/MS. Compared with cultivation on MRS broth, the L. rhamnosus strains cultivated under cheese-like conditions had modified amounts of some proteins responsible for protein biosynthesis, nucleotide, and carbohydrate metabolisms, the glycolysis pathway, proteolytic activity, cell wall, and exopolysaccharide biosynthesis, cell regulation, amino acid, and citrate metabolism, oxidation/reduction processes, and stress responses.

Stress Physiology of Lactic Acid Bacteria

“…LAB such as Lactobacillus plantarum, Lactobacillus reuteri, Lactobacillus rhamnosus, and Lc. lactis modify pyruvate metabolism at the expense of lactic acid, and they increase the synthesis of basic compounds (e.g., lysine and diacetyl/acetoin) (173,174), energy-rich intermediates (such as ATP and NADH) (175), EPS, and/or glycogen (176). The level of lactate dehydrogenase (Ldh), which is responsible for the synthesis of lactic acid from pyruvate, markedly decreases.…”

“…casei and Lb. rhamnosus also regulated their glycolytic enzymes differently (176,188). S. mutans modulated its metabolic activities through transcriptional and enzyme allosteric regulation in order to optimize the flow of carbohydrates and to maintain an optimal energy state (189).…”

“…lactis (325), whereas reduced salt and heat tolerance as well as diminished biofilm formation were reported for an Lb. plantarum ftsH mutant (176). Lb.…”

“…lactis and Lb. rhamnosus metabolize citrate and synthesize acetic acid and ATP under carbohydrate starvation conditions (176,195). The cofermentation of citrate and glucose in obligately heterofermentative LAB follows the pentose phosphate pathway, mainly producing lactic acid, ethanol/acetic acid, and ATP from the consumed glucose.…”

Genomics of Weissella cibaria with an examination of its metabolic traits

“…Glycogensynthesizing genes have recently been mentioned with respect to a Lactobacillus rhamnosus strain, but the presence of this trait in LAB has not been widely reported (Bove et al, 2012). A putative oligo-1,6-glucosidase (involved in the hydrolysis of a-1,6-D-glucosidic linkages) was annotated but contained an internal stop codon that probably abrogates activity.…”