Fig. 7

Degradation of filter paper by cellulase-displaying P. putida cells and mixtures thereof. The cells were cultivated to an OD of 0.5, protein expression was induced by the addition of 0.2 % l-arabinose, and after 4 h of further cultivation the cells were harvested and resuspended in 50 mM sodium citrate buffer, pH 6, to a final OD of 16.6. 23.6 µL of each cell suspension was added to the mixtures as indicated, filled up with buffer when necessary to a total volume of 71 µL, and incubated for 24 h with a round patch (6 mm diameter) of Whatman filter paper No. 1 at 55 °C. Subsequently, the cells were removed, reducing sugars were quantified via DNS assay (blue) and glucose was specifically determined by means of a commercial reagent kit (red)