POSSIBILITY OF INCREASING MECHANICAL PULP YIELD BY ENZYMATIC TREATMENT

The major polysaccharides dissolved in thermomechanical pulping of Norway spruce (Picea abies) are the O-acetyl-galactoglucomannans. Enzymatic treatment of a TMP suspension with an isolated acetyl esterase produced by Aspergillus oryzae resulted in deacetylation of dissolved galactoglucomannans which led to their adsorption onto the TMP fibers. The potential yield gain due to this treatment amounted to 1% based on the initial dry fiber used in preparation of the suspension. Industrial application of this biotechnical method may lead to decreased yield losses in mechanical pulping and, possibly, improvements in mechanical pulp strength.