In each bio-panning round, the input and output phases were titrated immediately before or after the experiment. The results of titrations are shown in Table . The presented mean p(O/I) value for each bio-panning round may be interpreted as the efficiency of phage binding. In chemical nomenclature, p(x) is defined as -log(x), so a higher p(O/I) means a lower ratio of phage outputinput. The p(O/I) value for the first panning round is relatively low. However, usage of more concentrated Tween-20 (from 0.1% to 0.5%) causes a significant increase in p(O/I) values for the second round (around 4) despite higher phage input. In addition, there is a difference between the second and the third p(O/I), which may be interpreted as an enrichment of TnTbinders in the phage pool, and it is the main aim of bio-panning via phage display. The increase in phage recovery yield is a widely reported observation by manufacturers and other authors .