EFFECTS OF LIGNIN ON THE HYDROLYSIS OF CELLULOSE BY PURE AND MULTICOMPONENT ENZYMES

The utilization of lignocellulose in second generation bioethanol requires pre-treatment technologies to break down the various physical and chemical barriers that inhibit the susceptibility for bioprocessing (including recalcitrance, cellulose access, etc.). Therefore, enzymatic hydrolysis of cellulose and the influence of lignin on bioconversion are critical in making any process viable.

Due to the complexity of lignocellulose systems most studies in this area have measured the overall production of sugars upon enzymatic hydrolysis of suspended substrates. However, the effect of lignin on cellulolytic reactions has not been addressed at the molecular and nano scales. Therefore, the objective of this work is to investigate the role of lignin on the dynamics and efficiency of biocatalytic conversion of cellulose by carrying out in-situ, real time quartz crystal microgravimetry experiments. To this end, novel bi-component thin films containing cellulose and lignin were employed.

A commercial multicomponent enzyme system as well as endoglucanase, EG I and exoglucanase, CBH I from Trichoderma reesei were used. It was found that both enzymes adsorbed onto neat cellulose or lignin films, although EG I exhibited a higher affinity to lignin. Due to the adsorption of enzyme onto lignin, a clear reduction in the hydrolysis rate was observed in the presence of lignin.