Isolation and characterization of tannin-degrading bacteria from faecal samples of some wild ruminants in Ethiopia

The aim of this study was to isolate and characterize bacteria capable of hydrolysing tannins from the faeces of Ethiopian ruminants adapted to feed on tannin-rich leaves. Faecal samples were collected from dikdik (Madoqua guentheri), camel (Camelus dromedaries), Grant's gazelle (Gazella granti), zebra (Equus quagga) and hartebeest (Alcelaphus buselaphus). Mixed cultures of the samples were screened for their tannin-hydrolysing capacities by thin layer chromatography (TLC). Twelve bacterial isolates with the ability to hydrolyse tannin were characterized morphologically, physiologically and by restriction fragment length polymorphism (RFLP) of the 16S rRNA genes of the isolates. Isolate Eden Ephraim 9 (EE9) completely degraded tannic acid, gallic acid and chestnut tannin. The other isolates could hydrolyse tannin to pyrogallol. Characterization of EE9 shows that the isolate is different from previously isolated tannin-tolerant bacteria. The bacteria isolated from some Ethiopian ruminants could partially or completely hydrolyse tannins and EE9 is possibly a new isolate, which may warrant further taxonomic studies. This study has shown the presence of bacteria in faecal materials of ruminants that can completely degrade tannin and which may be used to alleviate tannin toxicity problems in ruminants feeding on tannin-rich but nutritious fodder tree leaves.