Difference in influence of commercial industrial paints on microbial biofilms and planktonic cells

This study compares the effect of commercial industrial paints on the Escherichia coli PMFKG-F2, Proteus mirabilis PMFKG-F4 and Saccharomyces cerevisiae PMFKG-F6 planktonic cells and biofilms. A MBECTM-HTP assay and standard 96 microtiter plate assay were used to test the levels of resistance of planktonic cells and biofilms. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) of the tested substances, which affects planktonic cells and biofilms, were determined and the results were confirmed by fluorescence microscopy. Results obtained for planktonic cells were compared between them and with the results obtained for biofilms. Noticeable difference in the resistance between the biofilms and the planktonic cells on paints, was observed. The E. coli PMFKG-F2 planktonic cells showed the highest resistance in the presence of the tested substance 2 (MICp 2.5 μl/ml), while the P. mirabilis PMFKG-F4 planktonic cells showed the highest resistance in the presence of the tested substance 2 (MICp 5 μl/ml). The S. cerevisiae PMFKG-F6 planktonic cells showed the same level of resistance in the presence of the tested substances 1, 2 and 5 (MICp 0.62 μl/ml). The E. coli PMFKG-F2, P. mirabilis PMFKGF4 and S. cerevisiae PMFKG-6 biofilms showed the highest resistance in the presence of the tested substance 5 (MICb 125 μl/ml, MICb 125 μl/ml and MICb 62.5 μl/ml). The obtained results suggest that the biofilm may have a potential to be used in bioremediation of wastewater contaminated with industrial paints