POSSIBILITY OF INCREASING MECHANICAL PULP YIELD BY ENZYMATIC TREATMENT

The major polysaccharides dissolved in thermomechanical pulping of Nor way spruce (Picea abies) are the O-acetyl-galactoglucomannans. Enzymat ic treatment of a TMP suspension with an isolated acetyl esterase prod uced by Aspergillus oryzae resulted in deacetylation of dissolved gala ctoglucomannans which led to their adsorption onto the TMP fibers. The potential yield gain due to this treatment amounted to 1% based on th e initial dry fiber used in preparation of the suspension. Industrial application of this biotechnical method may lead to decreased yield lo sses in mechanical pulping and, possibly, improvements in mechanical p ulp strength.