Studies on Carboxymethyl Cellulase and Xylanase Activities of Anaerobic Fungal Isolate CR4 from the Bovine Rumen |
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Authors: | Hiroki Matsui Tomomi Ban-Tokuda |
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Institution: | (1) Graduate School of Bioresources, Mie University, Mie, Japan |
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Abstract: | An anaerobic fungal isolate, CR4, was isolated from the bovine rumen. The DNA sequence of internal transcribed spacer region
1 showed that CR4 belonged to the genus Caecocmyces. The dry matter digestibility of timothy hay by anaerobic fungal isolate CR4 was determined. The effects of carbohydrate
growth substrates on carboxymethyl cellulase (CMCase) and xylanase activities also were examined. The extent of dry matter
digestibility of timothy hay was 31% at 6 days’ incubation. The highest specific activity of CMCase in the culture supernatant
(SN) fraction was observed in xylose culture. The activity of CMCase was not detected in the SN fraction of cellobiose and
xylan or in the cell-bound fraction of all growth substrates. The highest specific activity of xylanase in the SN fraction
was observed in glucose culture. These results suggest that fiber-degrading enzyme activities were affected by growth substrates
and that CR4 is xylanolytic. Zymogram analysis showed that CR4 produces three CMCases of molecular mass (95, 89, and 64 kDa)
and three xylanases of molecular mass (82, 73, and 66 kDa). This is the first demonstration showing the molecular mass of
fiber-degrading enzymes of Caecomyces. |
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