Characterisation and application of glycanases secreted by aspergillus terreus CCMI 498 and trichoderma viride CCMI 84 for enzymatic deinking of mixed office wastepaper

摘要

Two enzymatic extracts obtained from xylan-grown Aspergillus terreus CCMI 498 and cellulose-grown Trichodermaviride CCMI 84 were characterised for different glycanase activities. Both strains produce extracellular endoxylanaseand endoglucanase enzymes. The enzymes optimal activity was found in the temperature range of 45-60 ºC.Endoglucanase systems show identical activity profiles towards temperature, regardless of the strain and inducingsubstrate. Conversely, the endoxylanases produced by both strains showed maximal activity at different pH values(from 4.5 to 5.5), being the more acidic xylanase produced by T. viride grown on cellulose. The endoglucanase activitieshave an optimum pH at 4.5-5.0. The endoxylanase and endoglucanase activities exhibited high stability at 50 ºC andpH 5.0. Mannanase, β-xylosidase, and amylase activities were also found, being the first two activities only present forT. viride extract. These two enzymatic extracts were used for mixed office wastepaper (MOW) deinking. When theenzymatic extract from T. viride was used, a further increase of 24% in ink removal was obtained by comparison withthe control. Both enzymes contributed to the improvement of the paper strength properties and the obtained resultsclearly indicate that the effective use of enzymes for deinking can also contribute to the pulp and paper propertiesimprovement.