The aim of this study was to understand how various lignocellulolytic enzymes applied on two different pre-treated wheat straw materials impacted the rheological properties. Pure and mixed thermostable cellulases were studied in combination with a pure xylanase to analyse their influence on viscosity and fiber properties.
Using a flow-loop setup with in-line magnetic resonance imaging (MRI) enabled continuous measurement of viscosity during hydrolysis. In addition, samples were frequently taken to follow the changes in fiber length and release of soluble sugars.
For all tested cellulases, viscosity dropped remarkably within the first hour of hydrolysis. Addition of xylanase to a cellulase mixture increased the rate of liquefaction, while the effect of xylanase added to an endoglucanase was negligible. No difference was observed in rheological properties when a cellulase mixture or a pure endoglucanase was applied with the same total enzyme loading.
The results of the viscosity measurements using MRI will be discussed in terms of results from fiber length analysis and the general saccharification. The results will provide an insight into the dynamic interaction between enzyme and biomass in early stage of hydrolysis.