Wood decay by a brown rot basidiomycete, Tyromyces palustris, 2: Effects of light and culture medium composition on extracellular xylanase activity
1991
Suzuki, T. (Tokyo Univ. of Agriculture (Japan)) | Higaki, M.
Tyromyces palustris (Berk. et Curt.) Murr. attacked hemicellulose prior to attacking cellulose during the early stage of wood decay. In this report, the effects of light and culture medium composition on the activity of one of the hemicellulase; the extracellular xylanase (beta-1,4-xylan xylanohydrolase, E.C. 3.2.1.8) in a shaking culture were studied. From our experimental results, it was evident that the activity of the extracellular xylanase was stronger under an irradiation of a 10W fluorescent lamp when incubated for five days with the culture medium containing 4.25% glucose than without the lamp, but this activity was not increased when incubated with the culture medium containing 0.25% glucose under light irradiation. Also, the xylanase activity was stronger when incubated with the culture medium containing wool meal (Cryptomeria japonica D.Don) than without wood meal. Furthermore, we also investigated the effects of the concentration of glucose in the culture medium without wood meal on the activity of extracellular xylanase. It was found that the xylanase activity was stronger under light irradiation when the tests were performed with the culture media containing 2.25% glucose than without the lamp. On the other hand, no such effects for light conditions were recognized when the culturings were performed with the culture medium containing 0.25% glucose. These results suggested that the activity of extracellular xylanase depends on the concentration of glucose in the culture medium and light irradiation during the incubation of the fungus, and that this enzyme activity may give extensive effects on the mass loss by T. palustris
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