Fermentace glukózy a rafinózy u Bifidobacterium breve a Bifidobacterium animalis

Fermentation of glucose and raffinose in bifidobacterium breve and bifidobacterium animalis

Fermentace glukózy a rafinózy u Bifidobacterium breve a Bifidobacterium animalis

Vojtěch RADA, Eva VLKOVÁ, Iva TROJANOVÁ

KMB AF ČZU

Souhrn, klíčová slova

Cílem práce bylo sledování parametrů růstové křivky u B. breve a B. animalis kultivovaných v přítomnosti glukózy, rafinózy a na směsi obou cukrů. Oba kmeny rostly signifikantně rychleji na rafinóze než na glukóze. Zatímco B. breve využíval oba cukry současně, B. animalis vykazoval atypický diauxický růst, při němž rychlá spotřeba rafinózy byla následována pomalou utilizací glukózy.

Bifidobakterie, růstové křivky, diauxie

Summary, keywords

The aim of the present work was to investigate B. breve and B. animalis for their growth parameters with either glucose, raffinose or a mixture of glucose and raffinose. Both strains grew significantly slower on glucose compared to raffinose. B. breve utilized glucose and raffinose simuntaneously. B. animalis displayed atypical diauxic growth in which rapid utilization of raffinose was followed by slow utilization of raffinose after the raffinose depletion.

Bifidobacteria, growth curves, diauxi

Introduction

Bifidobacteria are normal inhabitants of the human and animal hindgut exibiting positive health effects to their hosts. Raffinose-series oligosaccharidesch are major components of many food legumes. In lower intestine these oligosaccharides are preferentially metabolised by bifidobacteria, exibiting so called bifidogenic effects (Crittenden, 1999). Although little is known about the coutilization of different carbon sources in bifidobacteria, substrate preferences have been shown to occur in variety of human colonic bifidobacteria growing on mixtures of different monosaccharides (Degnan and Macfarlane, 1991). On the contrary, the preferences for mono and oligosaccharides have never been studied. Hence, the aim of the present work was to investigate the utilization of glucose and raffinose in Bifidobacterium breve and B. animalis to determine the dual-substate utilization pattern in these bacteria.

Methods

B. breve ATCC 15700 was obtained via Deutche Sammlung von Mikroorganismen und Zellkulturen (Braunschweig, Germany). B. animalis was isolated from fermented milk products. The isolate was identified using API 50 CHL and API ID 32A kits (BioMérieux, France). Turbidimetric methods was used for the determination of specific growth rates Enzymatic method (Raffinose-series oligosaccharides assay procedure, Megazyme, Ireland) was used for the determination of the dual substrate utilization patterns.

Results - discussion

Both strains grew significantly (P < 0.05) slower on glucose compared to raffinose (Tab.1). While there were no difference in the growth of B. animalis on raffinose and mixture of glucose and raffinose, B. breve grew significantly (P < 0.05) more rapidly on the mixture of glucose and raffinose compared to raffinose. B. breve utilized glucose and raffinose simultaneously. On the contary, B. animalis displayed atypical diauxic growth in which rapid utilization of raffinose was followed by slow utilization of glucose after the raffinose depletion (Fig 1).

Tab.1 Specific growth rates in bifidobacteria

Values in columns (n=6) with no common superscripts

differ (P < 0.05)

Fig.1. Utilization (in g/l) of glucose (-?-) and raffinose (-?-), and OD640nm (-?-) in B. animalis. The scale of x-axis is in hours.

References

Crittenden R.G.: In: Probiotics. Tannock G.W. (ed.) Norfolk, Horiyon Scientific Press. 141-156, 1999.

Degnan B.A., Macfarlane G.T.: FEMS Microbiology Letters 84: 151-156, 1991.

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