Differential Adsorption and Inhibition of Endoglucanase From Different Sources on Lignin and its Derivatives
The non-productive adsorption of cellulases on lignin and lignin derivatives has contributed towards the higher
enzyme loadings required for lignocellulose hydrolysis. Identifying weak lignin binding enzymes could be a novel way to
reduce the non-productive inhibition. In this study, endoglucanases from three different sources, namely termite metagenome
(TeEG), Aspergillus niger (AnEG) and Bacillus liquifaciens (BlEG) were incubated with carboxymethyl cellulose (CMC) in
the presence of high molecular weight lignin, HMWL and tannin) and low molecular weight lignin, LMWL compounds. The
LMWL compounds exhibited higher inhibitory effect compared to HMWL compounds. The highest inhibitory effect on
hydrolysis was observed with sinapyl alcohol, while the lowest inhibitory effect was observed in the presence of lignin. The
Langmuir adsorption isotherms indicated that TeEG exhibits the lowest adsorption and affinity constant on alkali lignin. An
increase in temperature from 50oC to 60oC increased the non-productive adsorption, while a shift in pH from 5.0 to 6.0
reduced the non specific adsorption on alkali treated lignin.
Keywords— Endoglucanases, lignin, non-productive adsorption.