Characterization of a major xylanase purified from Lentinula edodes cultures grown on a commercial solid lignocellulosic substrate

Abstract

The white-rot basidiomycete Lentinula (syn.Lentinus) edodes (Berk.) Pegler is the dominant edible mushroom cultivated on wood. The major xylanase detected in cultures grown on a commercial oak wood medium was extracted, purified, and characterized. The enzyme was a non-debranching endo-fl-D-xylanase (l,4fl-D-xylan xylanohydrolase; E.C.3.2.1.8) highly specific for xylans, with a molecular weight of 41000 (on sodium dodecyl sulfate gels) and an isoelectric point of 3.6. With aspen glucuronoxylan as substrate, the enzyme showed optimal activity at pH 4.5-5.0 and 60 ° C, with a K,~ of 0.66 mg/ml and specific activity of 310 units/rag protein at 40 ° C. It was capable of hydrolyzing (forming reducing sugars from) 40%-50% of the hydrolyzable linkages in either glucuronoxylan or arabinoxylan. The enzyme produced xylose and major identifiable products in the xylobiose or xylotriose (and presumably larger) size range including xylobiose and xylooligosaccharides, but neither glucuronic acid nor arabinose. Products were also produced from arabinoxylan that appeared to be arabinoxylobiose and arabinoxylotriose.

Purification and characterization of two 1,4-beta-xylan endohydrolases from the rumen fungus Neocallimastix frontalis

“…and a discrepancy in molecular masses estimated by gel filtration and SDS-PAGE. Similar behavior has been observed with other fungal xylanases (2,22,23,26).…”

“…Consequently, the rates of purification appeared to be low due to the overestimation of the xylanase activity in the crude preparation. This phenomenon is often observed during purification of fungal endoxylanases (6,22,23,26,32). Determination of molecular mass.…”

Thermostability of xylanolytic enzymes produced by Lentinula edodes UFV70

“…The maximum apparent activity occurred at a higher temperature (70 ºC) than previously reported (50-60 ºC) (7,8,11). Furthermore, these enzymes were considerably stable when pre-incubated up to 65 ºC, for up to 21 hours ( Figure 1).…”

Characterization of monoclonal antibodies to woodderived β-1,4-xylanase of Postia placenta and their application to detection of incipient decay

“…Previous estimations of the molecular weight of xylanase appear to be reduced by more complete solubilization with Triton X-100 and reduction in carbohydrate residues as reported by other authors (Gallagher & Evans, 1990;Magnuson et al, 1991). Xylanases characterized from other organisms are most commonly observed in the molecular weight range of 12-45 kDa (Mishra et al, 1990). This raises the possibility that complete solubilization would yield individual enzymes of smaller molecular weight.…”