Lastly, a vitamin solution (Wolin et al., 1963) was added
to each bottle. After five transfers in birchwood xylan-amended
medium, the enrichment culture (0.1 mL; successively diluted to
105 times) was repeatedly streaking on agar plates poured with
mineral salts medium containing birchwood xylan as the sole carbon
source. After incubation for six days, Congo red staining was
used to indicate xylanase activities of the colonies. The xylanase
activity of each colony was determined by measuring the zone of
clearance on the agar plates. Through such processes, a pure bacterial
culture, designated OM3, was obtained. All the enrichment,
isolation and cultivation were performed in an anaerobic chamber