Suriya Sawanon and Yosuo Kobayashi

pp. 351 - 361

Abstract

Fibrolytic Butyrivibrio fibrisolvens was an attractive target for genetic engineering in rumen bacteria. The experiment was initiated in making culture collection of this species, some of which may be useful as candidate strain in the future. Hay suspended in sheep rumen was used as the source of isolates. The source was enriched with filter paper degradation, diluted with an anaerobic solution and used for pure culturing by a roll tube technique. After colony forming, Gram-negative curved rods bacteria were selected and screened for further identification with volatile fatty acid (VFA) profiling and 16S rDNA sequencing. Fibrolytic strains were selected to find fibrolytic enzymes and attachment to and digestion of various fibers. Fortyseven strains of Gram-negative curved rods were isolated. After determining cellulase, xylanase activities and VFA profile, 2 strains were chosen and employed for 16S rDNA sequencing. Both strains producing butyrate were B. fibrisolvens. Of these 2 strains, most fibrolytic S-28 was selected. The strain S-28 could
degrade natural fibers but not cellulose and showed strong attachment to them. A strong xylanase activity was detected and presence of cellulase, β-glucosidase, β-xylosidase, α-L-arabinofuranosidase and βcellobiosidase were also demonstrated.

Keywords

• rumen bacteria
• fiber digestion
• Butyrivibrio fibrisolvens