Figure 3

Iterative improvement of enzyme fitness after screening on xylanase-depleted wheat straw (Dpl-WS). The x-axis represents clones in a microtiter plate, randomly selected from a wild-type control series (open triangles, using Thermobacillus xylanilyticus xylanase (Tx-Xyn)-AF7 coding sequence), fourth random mutagenesis library (filled triangles), fifth recombinant library (open squares) and sixth recombinant library (filled circles). The y-axis indicates the activity value of corresponding clone in the screening. The same batch of Dpl-WS substrate was used for the four experiments.