ENZYMATIC DEACETYLATION OF GALACTOGLUCOMANNANS

Several hemicellulolytic microorganisms were screened for their capabi lity of liberating acetyl side groups from native softwood galactogluc omannan. All the microorganisms tested were found to produce an extrac ellular acetyl glucomannan esterase(s). The highest activity was detec ted in Schizophyllum commune culture filtrate. However, the enzyme pro duced by Aspergillus oryzae was most efficient in long-term hydrolysis . Acting alone, the purified esterase of A. oryzae was able to liberat e most of the acetic acid from galactoglucomannan. The addition of oth er galactoglucomannan-degrading enzymes did not affect the action of e sterase. On the other hand, the addition of esterase clearly enhanced the action of mannanase and alpha-galactosidase. The purified acetyl e sterase of Trichoderma reesei was able to liberate acetic acid from sh ort oligomers of glucomannan, whereas the acetyl xylan esterase of T. reesei was unable to act on glucomannan oligomers of any size.