FUNCTION OF ENDOGLUCANASE I IN THE DEINKING PROCESS OF MIXED OFFICE WASTE PAPER

The performance of endoglucanase I (EG Ι) was investigated in the deinking process of mixed office waste paper(MOW). Results showed the optimal treatment conditions of temperature 60℃,pH value 7.5, treated time 40 min and enzyme dosage 0.5 IU per gram pulp. Though enzymic treatment decreased the degree of polymerization(DP) of pulp, the DP decreased limitedly within definite enzyme dosage. EG Ι played an important role in the deinking process of MOW because the improvement of ink-removal in floated pulp after EG Ι treatment was achieved. Meantime the existence of ash in waste paper with fillers or coating (consisted mainly of CaCO3) affected deinking efficiency. An acid treatment could enhance deinking efficiency and further improved the deinking effectiveness of EG Ι.