Study of the influence of the presence of Dr fimbriae on the hydrophobicity of cells of recombinant Escherichia coli strains: AAEC191A and BL21(DE3)

The ability of a cell surface to repel or adhere to surfaces is crucial, and it was assessed through a microbiological adhesion test involving hexadecane and xylene. In this method, microorganisms in an aqueous layer are mixed with an organic layer, and after completion, the absorbance of each sample is measured at a 570 nm wavelength. The results obtained are essential for calculating the percentage of cell adherence to the organic layer, as defined by the formula below.
% of adhesion=(A0-A1)/A0 * 100%
Where:
A0 represents the absorbance of aqueous cell suspensions that have not been mixed with the organic layer.
A1 represents the absorbance of aqueous cell suspensions that have been mixed with the organic layer.
The analysis of results was conducted using the criteria proposed by Santos et al. (1990), which suggests that the surface of the examined cells is hydrophilic if the percentage of adherence to the organic phase is <20%, moderately hydrophobic if 20-50%, and hydrophobic if >50%.