Biochemical properties of a β-mannanase and a β-xylanase produced by Ceriporiopsis subvermispora during biopulping conditions

Abstract

One mannanase and one of the three xylanases produced by Ceriporiopsis subvermispora grown on Pinus taeda wood chips were characterized. A combination of ion exchange chromatography and SDS-PAGE data revealed the existence of a high-molecular-weight mannanase of 150 kDa that was active against galactoglucomannan and xylan. Its activity was optimal at pH 4.5. The K m value with galactoglucomannan as substrate was 0.50 mg ml −1. One xylanase with molecular mass of 79 kDa was also purified and characterized. Its activity was optimal at 60 °C and pH 8.0. Its K m value with birchwood xylan as substrate was 1.65 mg ml −1. Both the mannanase and the 79 kDa xylanase displayed relatively high activity on carboxymethyl cellulose. The sensitivity of the xylanase and mannanase to various salts was evaluated. None of the tested salts inhibited the xylanase, but Mn +2, Fe +3, and Cu +2 were strong inhibitors for the mannanase.