Lactobacilli isolated from sugary kefir grains capable of polysaccharide production and minicell formation

Pidoux, M.; Marshall, Valerie M.; Zanoni, Paolo; Brooker, B. E.

doi:10.1111/j.1365-2672.1990.tb01521.x

Cited by 36 publications

(32 citation statements)

References 23 publications

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“…For EPS isolation, many authors used one or more steps of selective EPS precipitation by adding one, two or more volumes of cold ethanol [7,11,26,[31][32][33][34]; others used the same procedure with a final step of dialysis [2,5,20,21,25,30]. Other researchers preferred a step of TCA precipitation to remove contaminating material (proteins, polypeptides) combined with a final step of dialysis [9,16].…”

Section: Discussionmentioning

confidence: 99%

Comparative study of different methodologies to determine the exopolysaccharide produced by kefir grains in milk and whey

Rimada

Abraham

2003

Lait

100

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-Quantitative isolation of lactic acid bacteria exopolysaccharides (EPS) from dairy products is an important step to determine small amounts of EPS (between 25 and 890 mg·L -1 ) in a medium that contains 30 to 50 g·L -1 of lactose. Kefir grains CIDCA AGK1 are able to produce an exopolysaccharide commonly known as kefiran when grown in milk and deproteinised whey. Different methodologies were compared for kefiran isolation from milk and whey fermented for 96 h at 20°C with 100 g·L -1 of kefir grains. Methods that included one or two steps of ethanol precipitation, one step of ethanol precipitation followed by dialysis, direct dialysis with membranes of different cut-off (1 000, 6 000, 12 000), and a TCA precipitation step were evaluated. The effect of a heat treatment of the milk on EPS recovery was also studied. The highest recovery of EPS was obtained when samples were heated as a first step of isolation. Methods that contained two steps of ethanol precipitation, one step of ethanol precipitation followed by dialysis or direct dialysis (molecular weight cut-off lower than 6 000 to 8 000) gave the highest values of polysaccharide concentration (218 mg·L -1 of fermented milk and 247 mg·L -1 of fermented whey). One step of ethanol precipitation did not completely eliminate residual lactose. EPS was partially lost when dialysis was carried out with membranes of cut-off of 12 000. About 50% of EPS was lost when the method included a step of TCA precipitation. We conclude that polysaccharide quantified in milk and deproteinised whey fermented with kefir grains strongly depends on the isolation methodology used. Exopolysaccharide / EPS isolation / fermented milk / fermented whey / kefirRésumé -Étude comparative de différentes méthodologies pour déterminer la quantité d'exopolysaccharide produit par les grains de kefir dans le lait et le lactosérum. L'isolement quantitatif des exopolysaccharides (EPS) de bactéries lactiques à partir des produits laitiers est une étape importante pour déterminer de petites quantités d'EPS (entre 25 et 890 mg·L -1 ) dans un milieu contenant entre 30 et 50 g·L -1 de lactose. Quand les grains de kefir AGK1 croissent dans le lait et dans le lactosérum deprotéiné, ils sont capables de produire un EPS généralement connu comme kefiran. Dans ce travail, nous avons comparé différentes méthodologies pour isoler le kefiran dans du lait et du lactosérum fermentés. Pour réaliser ces essais le lait et le lactoserum ont été fermentés pendant 96 h 20°C avec 100 g·L -1 de grains de kefir. Les différentes méthodologies pour déterminer l'EPS sont: la précipitation à l'ethanol, la précipitation à l'ethanol suivie d'une dialyse, une dialyse directe

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Section: Discussionmentioning

confidence: 99%

Comparative study of different methodologies to determine the exopolysaccharide produced by kefir grains in milk and whey

Rimada

Abraham

2003

Lait

100

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“…Even if culture conditions are standardized, the control of all parameters appears difficult, since adaptation and growth in synthetic culture medium might differ according to the strain. Molecular approaches based on total genomic DNA hybridization cannot clear up the problem, owing to the fact that some cross-hybridization between L. brevis and L. hilgardii is observed (Vescovo et al, 1979 ;Pidoux et al, 1990 ;Lonvaud-Funel et al, 199 1). Therefore, PCR methods were developed for a better understanding of the taxonomic relationships within these two lactic acid bacteria species.…”

Section: Discussionmentioning

confidence: 99%

Molecular identification of Lactobacillus hilgardii and genetic relatedness with Lactobacillus brevis

Sohier¹,

Coulon²,

Lonvaud-Funel³

1999

International Journal of Systematic and Evolutionary Microbiology

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Conventional phenotypic methods lead to misidentification of the lactic acid bacteria Lactobacillus hilgardii and Lactobacillus brevis. Random amplified polymorphic DNA (RAPD) and repetitive element PCR (REP-PCR) techniques were developed for a molecular study of these two species. The taxonomic relationships were confirmed by analysis of the ribosomal operon. Amplified DNA fragments were chosen to isolate L. hilgardii-specific probes. In addition to rapid molecular methods for identification of L. hilgardii, these results convincingly proved that some strains first identified as L. brevis must be reclassified as L. hilgardii. The data clearly showed that these molecular methods are more efficient than phenotypic or biochemical studies for bacterial identification at the species level.I

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“…Few studies have focused on the synthesis of homopolysaccharides by lactobacilli (Dunican and Seeley 1965;Pidoux et al 1990;Sharpe et al 1972). Limited information thus is available about glucan synthesis, and no reports have appeared about fructan synthesis by lactobacilli.…”

Section: Introductionmentioning

confidence: 99%

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

Geel-Schutten

Flesch

Brink

et al. 1998

Applied Microbiology and Biotechnology

160

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A total of 182 Lactobacillus strains were screened for production of extracellular polysaccharides (EPS) by a new method: growth in liquid media with high sugar concentrations. Sixty EPS-positive strains were identi®ed; 17 strains produced more than 100 mg/l soluble EPS. Sucrose was an excellent substrate for abundant EPS synthesis. The ability to produce glucans appears to be widespread in the genus Lactobacillus. The monosaccharide composition of EPS produced by Lactobacillus reuteri strain LB 121 varied with the growth conditions (solid compared to liquid medium) and the sugar substrates (sucrose or ranose) supplied in the medium. Strain LB 121 produced both a glucan and a fructan on sucrose, but only a fructan on ranose. This is the ®rst report of fructan production by a Lactobacillus species. EPS production increased with increasing sucrose concentrations and involved extracellular sucrase-type enzymes.

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Lactobacilli isolated from sugary kefir grains capable of polysaccharide production and minicell formation

Cited by 36 publications

References 23 publications

Comparative study of different methodologies to determine the exopolysaccharide produced by kefir grains in milk and whey

Comparative study of different methodologies to determine the exopolysaccharide produced by kefir grains in milk and whey

Molecular identification of Lactobacillus hilgardii and genetic relatedness with Lactobacillus brevis

Screening and characterization of Lactobacillus strains producing large amounts of exopolysaccharides

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