Effect of dissolved lignin and related compounds on the enzymatic hydrolysis of cellulose model compound

The effect of lignin and related compounds on the hydrolysis of the cellulo se model compound (carboxymethylcellulose) by cellulase was investigated. L ignin, black liquor from the kraft pulping process and guaiacol, vanillin, vanillic acid, acetovanillone and protocatechuic acid were studied. Althoug h the Lignin related compounds affect differently cellulose hydrolysis, the y all improve hydrolysis at some concentrations. The addition of acetovanil lone or protocatechuic acid improved the hydrolysis of cellulose at low con centrations (0.05% and 0.005%, respectively), but inhibited the enzyme acti vity at much higher concentrations. The addition of increasing amounts of v anillin, vanillic acid, and guaiacol enhanced hydrolysis. In a similar mann er, addition of both lignin and black liquor also increased the activity of cellulase with increasing their concentration. Observation by circular dic hroism revealed a change in cellulase structure, indicating binding of the enzyme to some components of the black liquor. It appears that no deactivat ion of cellulase occurs due to the addition of either dissolved lignin or b lack Liquor, rather the interaction between the enzyme and lignin or black liquor results in an enhancement of hydrolysis.