5-48: The relationship between fiber size and viscosity during enzymatic degradation of wheat straw

When processing of lignocellulosic biomass the ability of the enzymes to decrease the viscosity of a fiber slurry is important for effcient mixing and processing.

A technique normally used measure cellulose fiber dimensions in the paper industry was used for to measure fiber length and width of a random 100,000 fibers for each set of measurements. The change in fiber lengths with hydrolysis time was analyzed for a commercial multi component enzyme mixture (Celluclast) and a mono component EGII (Cel5A) enzyme. The EGII was more efficient than the Celluclast in quickly breaking down the fibers at short hydrolysis times ( < 6 hr) to small fragments. The sum total of lengths of the 100,000 fibers measured was also compared. This showed that the Celluclast kept breaking down the fibers till the longest hydrolysis time of 48 hr, this was not the case for the EGII.

Both enzymes were capable of decreasing the voiscosity of a suspension of paper fibers. Interestingly we found no correlation between the initial fast drop in fiber length and viscosity in case of the EGII. Both systems fit well with the power law model for viscosity. Cellclast, by far, showed the fastest and most drop in the consistency index, K_pl.