Biological de-inking method

摘要

A method of de-inking wastepaper by pulping the paper in the presence of an enzyme is disclosed. The enzyme dislodges the ink particles from the paper fibers. The preferred enzymes are the acid resistant carbohydrases. The de-inking medium is an aqueous solution of the enzyme, preferably maintained at a pH less than about 7 and at a temperature between about 20 DEG C. and about 60 DEG C. No conventional chemical de-inking agents are required. The dislodged ink particles may be removed by any conventional method, such as flotation or washing.