Bleaching with lignin-oxidizing enzymes.

General concern about the environmental impact of chlorine bleaching effluents has led to a trend towards elementary chlorine-free or totally chlorine free bleaching methods. Considerable interest has been focused on the use of biotechnology in pulp bleaching, as large number of microbes and the enzymes produced by them are known to be capable of preferential degradation of native lignin and complete degradation of wood. Enzymes of the hemicellulolytic type, particularly xylan-attacking enzymes xylanases are now used commercially in the mills for pulp treatment and subsequent incorporation into bleach sequences.