1992 Volume 25 Issue 6 Pages 639-644
For the purpose of cellobiose production from cellulose, removal of β-glucosidase from cellulase was studied. This purpose can be achieved by an affinity precipitation technique using a reversibly soluble polymer depending on PH.
The polymer was hydroxypropyl methyl cellulose acetate succinate (AS-LF). β-glucosidase did not conjugate AS-LF, while the rest of the components did. The conjugated components gave high cellobiohydrolase and endo-β-1,4-glucanase activities. These components were detached by centrifuging with 1.0 M acetate buffer, pH 3.5 from AS-LF, but it was impossible to detach these components by 0.1 M acetate buffer, pH 5.0.
Hydrolysis of three kinds (KC-flock, Pulp-flock and Avicel) of cellulose powders with these detached components from AS-LF was carried out. The soluble reducing sugar contained glucose and cellobiose, and the cellobiose content in the product was over 50 mol% for each substrate. Moreover, when the hydrolysis was carried out using the solubilized AS-LF conjugating the components of high cellobiohydrolase and endo-β-1,4-glucanase activities, continuous cellobiose production could be performed by means of repeated affinity precipitation as follows. The reaction products from the insolubilized AS-LF and the residual substrate were separated by adjusting the PH of the reaction medium at an appropriate interval, and the precipitates were dissolved again to continue the reaction.