The fructanolytic abilities of the rumen bacterium Butyrivibrio fibrisolvens strain 3071

To determine if Butyrivibrio fibrisolvens strain 3071 is able to use fructose polymers for growth and to identify the enzymes involved in their digestion.

Strain 3071 utilized 97, 89, 85 and 60% of sucrose, timothy grass fructan, inulin oligosaccharides and inulin, respectively, in the growth medium. A cell extract from timothy grass fructan-grown bacteria was used for identification of fructanolytic enzymes by anion exchange chromatography, gel filtration, zymography and thin-layer chromatography. The bacterium synthesizes a specific endolevanase and a nonspecific β-fructofuranosidase. Both enzymes occurred in two forms differing in molecular weight. The β-fructofuranosidase was not able to digest long-chain inulin or timothy grass fructan, but degraded inulin oligosaccharides and sucrose. Addition of 1,4-dithioerythritol to an enzyme solution did not affect the activity of endolevanase(s), but increased the ability of β-fructofuranosidase to digest sucrose. The digestion of timothy grass fructan by endolevanase(s) was described by Michaelis-Menten kinetics in which Km  = 2·82 g l(-1) and Vmax  = 4·01 μmoles reducing sugar equivalents × mg(-1)  × min(-1) .

Strain 3071 synthesizes enzymes enabling it to use grass fructans for growth.

Butyrivibrio fibrisolvens strain 3071 can be considered a member of the rumen fructanolytic guild.