Isolation of Lecythophora sp. YP363, a secretor of various thermostable plant cell wall-degrading enzymes with high activity

Abstract

A fungal strain that produces high activities of various plant cell wall degrading enzymes such as CMCase, filter paperase, β-glucosidase, avicelase, xylanase and pectinase with high activities was isolated from soil surrounding rotten wood. The strain was identified asLecythophora sp. YP363 based on its ITS, 18S and 26S sequences. The specific activities of the various plant cell wall-degrading enzymes of Lecythophora sp. YP363 were, depending on the enzyme, identical to or much higher than those of Trichoderma reesei Rut C-30. Notably, the specific activities of the β-glucosidase, xylanase and pectinase of Lecythophora sp. YP363 were 4.6, 1.9 and 3.2 times higher, respectively, than those of T. reesei Rut C-30. The residual activities of CMCase, FPase and avicelase of Lecythophora sp. YP363 after the heat treatment at 60°C for 1 h were 100% or close to 100%, whereas the enzymes of T. reesei Rut C-30 are not resistant to heat treatment, that is, the residual activities of all the T. reesei Rut C-30 enzymes were only 36.9 ~ 41.9%. This result indicated that the enzymes of Lecythophora sp. YP363 were quite stable to heat treatment. Therefore, Lecythophora sp. YP363 has a potential as an alternative fungal strain to T. reesei in the lignocellulosic biomass-based industry. Key words: Lecythophora sp., thermostable, plant cell wall degrading enzymes,Trichoderma reesei Rut-C30.