Citrate metabolism by <i>Lactobacillus plantarum</i> isolated from orange juice

T . P AL L ES , T . BE RE S FO RD , S. CO N DO N A N D T .M . CO GA N . 1998. Information on the factors influencing citrate metabolism in lactobacilli is limited and could be useful in understanding the growth of lactobacilli in ripening cheese. Citrate was not used as an energy source by either Lactobacillus casei ATCC 393 or Lact. plantarum 1919 and did not affect the growth rate when co-metabolized with glucose or galactose. In growing cells, metabolism of citrate was minimal at pH 6 but significant at pH 4·5 and was greater in cells co-metabolizing galactose than in those co-metabolizing glucose or lactose. In non-growing cells, optimum utilization of citrate also occurred at pH 4·5 and was not increased substantially by the presence of fermentable sugars. In both growing and non-growing cells, acetate and acetoin were the major products of citrate metabolism; pyruvate was also produced by non-growing cells and was transformed to acetoin once the citrate was exhausted. Citrate was metabolized more rapidly than sugar by non-growing cells; the reverse was true of growing cells. Citrate metabolism by Lact. plantarum 1919 and Lact. casei ATCC 393 increased six-and 22-fold, respectively, when the cells were pre-grown on galactose plus citrate than when pre-grown on galactose only. This was probably due to induction of citrate lyase by growth on citrate plus sugar. These results imply that lactobacilli, if present in large enough numbers, can metabolize citrate in ripening cheese in the absence of an energy source.

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“…The findings on citrate support the data of Kennes et al (1991) for three strains of Lact. plantarum.…”

Section: Lactobacillus Plantarum 1919supporting

confidence: 80%

Citrate metabolism in Lactobacillus casei and Lactobacillus plantarum

Palles

Beresford

Condón

et al. 1998

Journal of Applied Microbiology

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“…Qualquer fruta que contenha níveis razoáveis de açú-car é possível de se produzir um bom vinho, com sabores característicos de cada fruta. Segundo a Legislação Brasileira, os vinhos são divididos quanto à classe em: vinho de mesa, com um teor alcoólico de Durante o processo fermentativo com o S. cerevisiae as principais variáveis devem ser bem controladas, caso contrá-rio, podem ocorrer variações na composição química do suco pela presença do Gluconobacter oxydans 5 , variação no conteú-do de ácido ascórbico 6 , fermentação do citrato, juntamente com a glicose, na presença do L. plantarum com a produção de ácido acético e do vinagre 7,8,9 , etc. A fabricação caseira do vinho de laranja, utilizando-se frutos que não encontram demanda comercial devido a defeitos nas cascas e tamanhos, foram investigados como alternativa de consumo das mesmas.…”

Section: Obtenção Do Vinhounclassified

Preparação e caracterização do vinho de laranja

Corazza¹,

Rodrigues²,

Nozaki³

2001

Quím. Nova

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“…Citrate metabolism plays an important role in many food fermentations involving lactic acid bacteria, since it occurs in many natural substrates, such as milk, vegetables, and fruits (21). The behavior of lactic acid bacteria may differ from one species to another, and not all lactic acid bacteria are able to metabolize citrate (24).…”

mentioning

confidence: 99%

Citrate Metabolism by Enterococcus faecalis FAIR-E 229

Sarantinopoulos

Kalantzopoulos

Tsakalidou

2001

Appl Environ Microbiol

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Citrate metabolism by Enterococcus faecalis FAIR-E 229 was studied in various growth media containing citrate either in the presence of glucose or lactose or as the sole carbon source. In skim milk (130 mM lactose, 8 mM citrate), cometabolism of citrate and lactose was observed from the first stages of the growth phase. Lactose was stoichiometrically converted into lactate, while citrate was converted into acetate, formate, and ethanol. When de Man-Rogosa-Sharpe (MRS) broth containing lactose (28 mM) instead of glucose was used, E. faecalis FAIR-E 229 catabolized only the carbohydrate. Lactate was the major end product, and small amounts of ethanol were also detected. Increasing concentrations of citrate (10, 40, 70, and 100 mM) added to MRS broth enhanced both the maximum growth rate of E. faecalis FAIR-E 229 and glucose catabolism, although citrate itself was not catabolized. Glucose was converted stoichiometrically into lactate, while small amounts of ethanol were produced as well. Finally, when increasing initial concentrations of citrate (10, 40, 70, and 100 mM) were used as the sole carbon sources in MRS broth without glucose, the main end products were acetate and formate. Small amounts of lactate, ethanol, and acetoin were also detected. This work strongly supports the suggestion that enterococcal strains have the metabolic potential to metabolize citrate and therefore to actively contribute to the flavor development of fermented dairy products.The industrial importance of lactic acid bacteria is mainly based on the ability of these organisms to rapidly ferment carbohydrates and to convert them into lactic acid and, to a lesser degree, into other flavor compounds. Lactic acid provides protection against spoilage by nonacidophilic organisms. On the other hand, many lactic acid bacteria are also able to ferment a number of noncarbohydrates, including citrate. Citrate metabolism plays an important role in many food fermentations involving lactic acid bacteria, since it occurs in many natural substrates, such as milk, vegetables, and fruits (21). The behavior of lactic acid bacteria may differ from one species to another, and not all lactic acid bacteria are able to metabolize citrate (24).The ability to metabolize citrate is invariably linked to endogenous plasmids that contain the gene encoding the transporter which is responsible for citrate uptake from the medium (2). Since citrate is a highly oxidized substrate, no reducing equivalents, such as NADH, are produced during its degradation, which results in the formation of metabolic end products other than lactic acid. Some of these end products, such as diacetyl, acetaldehyde, and acetoin, have very distinct aroma properties and significantly influence the quality of fermented foods (20). For instance, diacetyl determines the aromatic properties of fresh cheese, fermented milk, cream, and butter (12) but is considered the most important off-flavor compound in the brewing process and in the wine industry (22). The breakdown of citrate also results in the p...

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Citrate metabolism by Lactobacillus plantarum isolated from orange juice

Cited by 34 publications

References 14 publications

Citrate metabolism in Lactobacillus casei and Lactobacillus plantarum

Citrate metabolism in Lactobacillus casei and Lactobacillus plantarum

Preparação e caracterização do vinho de laranja

Citrate Metabolism by Enterococcus faecalis FAIR-E 229

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