Lactobacillus casei metabolic potential to utilize citrate as an energy source in ripening cheese: a bioinformatics approach

Díaz-Muñiz, I.; Banavara, Dattatreya S.; Budinich, M.; Rankin, Scott A.; Dudley, Edward G.; Steele, J. L.

doi:10.1111/j.1365-2672.2006.02965.x

Cited by 50 publications

(37 citation statements)

References 35 publications

(66 reference statements)

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“…rhamnosus have been shown to convert citrate to succinate (2,33,34), while several other species of the same genus were shown not to be able to catabolize citrate (35). The conversion of citrate to succinate follows the reductive tricarboxylic acid (TCA) pathway and is typified by the presence of a transporter, termed CitT, that catalyzes the uptake of citrate in exchange with the end product suc- (27). In line with these observations, the genome of Lb.…”

Section: Discussionsupporting

confidence: 51%

“…No special precautions were made in the latter experiments to deplete the experimental system from residual Ca 2ϩ , and it is tentatively concluded that the Ca 2ϩ -citrate complex is the main inducing agent, which is also in line with the high affinity of the pathway for the complex. Ca 2ϩ contamination of media would explain the observed citrate consumption during growth in the absence of added Ca 2ϩ reported in previous studies (25)(26)(27). In spite of the significantly different citrate metabolic activities, growth of Lb.…”

Section: Specificity and Induction Of The Citrate Metabolic Pathway Ofmentioning

confidence: 78%

“…Further metabolism of acetoin to 2,3-butanediol was not observed, which is in line with the absence of the encoding gene on the chromosome. The amount of acetate formed in excess of the equimolar amount formed by citrate lyase most likely also originates from pyruvate, for which a number of possibilities have been suggested (10,27), involving the pyruvate dehydrogenase (PDH), pyruvate oxidase (POX), and/or pyruvate-formate lyase (PFL) enzymes, the genes of which are all present in the Lb. casei ATCC 334 genome ( Table 2).…”

Section: Discussionmentioning

confidence: 99%

“…A number of studies have suggested that Lb. casei is able to derive metabolic energy from citrate metabolism, and energy-producing pathways have been proposed based on the genome sequence and metabolic flux analyses (26,27,36). ATP production by acetate kinase plays a pivotal role in these models.…”

Section: Discussionmentioning

confidence: 99%

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Ca ²⁺ -Citrate Uptake and Metabolism in Lactobacillus casei ATCC 334

Mortera

Pudlik

Magni

et al. 2013

Appl Environ Microbiol

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The putative citrate metabolic pathway in Lactobacillus casei ATCC 334 consists of the transporter CitH, a proton symporter of the citrate-divalent metal ion family of transporters CitMHS, citrate lyase, and the membrane-bound oxaloacetate decarboxylase complex OAD-ABDH. Lactobacillus represents a large genus of Gram-positive bacteria that contains over 100 species (1). Among these, Lactobacillus casei is a facultative heterofermentative lactic acid bacterium (LAB) that can be isolated from diverse environments. It is an important nonstarter lactic acid bacterium commonly present in cheese and dairy products. The most important energy and carbon source for LAB in general is lactose, which is abundantly present in milk, but few LAB have in addition the capacity to metabolize citrate, which is present in cheese curd at a concentration of approximately 10 mmol · kg Ϫ1 . Citrate fermentation by bacteria proceeds via two main routes that are catalyzed by a variety of enzymes and transporters. The genes encoding the citrate lyase complex and accessory proteins are diagnostic for citrate fermentation by bacteria. Citrate lyase catalyzes the common, first metabolic step in the pathways, i.e., the splitting of internalized citrate in oxaloacetate and acetate. The two main pathways diverge at oxaloacetate yielding succinate or pyruvate. The route to succinate via malate and fumarate is found in many lactobacilli but also in the gammaproteobacterium Escherichia coli (2). The pathway is characterized by a transporter that takes up citrate in exchange for the end product succinate (precursor-product exchange). The transporter is a member of the divalent anion:Na ϩ symporter (DASS) family of secondary transporters (3, 4). The second pathway involves decarboxylation of oxaloacetate, yielding pyruvate, which is added to the central pyruvate pool in the glycolytic pathway during carbohydrate/citrate cometabolism. In LAB, redundant pyruvate in the pool is converted to the flavor compound acetoin. In different bacteria, the pathway up to pyruvate is catalyzed by different combinations of a transporter responsible for the uptake of citrate and an enzyme (complex) that decarboxylates oxaloacetate, which has consequences predominantly for the energetics of the pathways. In Gram-negative bacteria like Klebsiella pneumoniae, citrate is taken up by an Na ϩ -dependent symporter, termed CitS, and oxaloacetate is decarboxylated by a membrane-bound complex, termed OAD, that conserves the free energy released in the reaction by pumping out Na ϩ ions (5, 6). Subsequently, pyruvate is converted to acetate via the acetate kinase route, which yields 1 ATP per molecule of pyruvate. The free-energy yield is high enough to allow the organism to grow on citrate as the sole energy source (7,8). In LAB like Lactococcus lactis and Leuconostoc mesenteroides, a cytoplasmic oxaloacetate decarboxylase, termed CitM, which does not conserve the free energy released in the reaction (9), is combined with a transporter, termed CitP, that functions as a citrate...

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Section: Discussionsupporting

confidence: 51%

Section: Specificity and Induction Of The Citrate Metabolic Pathway Ofmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Ca ²⁺ -Citrate Uptake and Metabolism in Lactobacillus casei ATCC 334

Mortera

Pudlik

Magni

et al. 2013

Appl Environ Microbiol

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“…When NSLAB cell numbers increase, most of the residual lactose in cheese has been utilized by SLAB; therefore, NSLAB seem to better adapt to the absence of lactose in cheese than SLAB. This is dependent on their ability to utilize the substrate potentially available like milk components, bacterial metabolites, and cell lysis products (38). In a PDO long-ripened Italian cheese such as Parmigiano Reggiano, NSLAB population is mainly formed by L. paracasei, Lactobacillus rhamnosus, and Pediococcus acidilactici.…”

Section: Parmigiano Reggiano Pdomentioning

confidence: 99%

The Microfloras and Sensory Profiles of Selected Protected Designation of Origin Italian Cheeses

Licitra

Carpino²

2014

Microbiol Spectr

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Approximately 39 Italian cheeses carry protected designation of origin (PDO) status. These cheeses differ in their manufacturing technology and the microbial flora which comprise the finished products. The evolution of lactic microflora in cheeses with PDO status is of particular interest because the biochemical activities of these organisms participate in cheesemaking and may play an acknowledged role in the development of organoleptic characteristics during ripening. Nonstarter lactic acid bacteria (NSLAB) constitute complex microbial associations that are characterized by the occurrence of various species and many biotypes as a result of a number of selective conditions persisting during the manufacturing process and different ecological niches. The evolution of different species during ripening of Fiore Sardo showed that, when present, Lactobacillus paracasei persists and dominates the microflora of the cheese in the last period of ripening, suggesting that this species, more resistant to the constraints of the mature cheese, could be involved in proteolysis and in other enzymatic processes occurring during cheese ripening. In contrast, the stretching step typical of pasta filata cheese, such as Ragusano, induced a simplification of the raw milk profiles, allowing the persistence only of some predominant species, such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. lactis, Lactococcus lactis, and Streptococcus macedonicus, after the stretching step. Lactobacillus plantarum and L. paracasei were isolated from ripened Castelmagno PDO cheese samples with the highest frequencies. These species, generally absent in the milk, occur in dairy ecosystems and dominate the bacterial flora of many ripened semihard cheeses. In PDO long-ripened Italian cheese such as Parmigiano Reggiano, the NSLAB population is mainly formed by L. paracasei, Lactobacillus rhamnosus, and Pediococcus acidilactici. Lactobacillus helveticus, L. delbrueckii subsp. lactis, and L. delbrueckii subsp.bulgaricus were also detected. Continued insight into the microbial populations of traditional Italian cheeses will allow continued production of characteristic, high-quality cheeses which have been enjoyed for many centuries.

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