Single-species biofilms from autochthonous microorganisms: biotechnological potential in automotive wastewater treatment

This study monitors the influence of basic automotive paints on plankton and biofilms of selected microorganisms isolated from the wastewater of an automotive factory. Minimum Biofilm Eradication Concentration-High Throughput Plates system was used for the simultaneous tolerance testing. Minimal inhibitory concentration and minimal lethal concentration of the tested substances were determined for both planktonic cells and their biofilms. The resistance level of biofilms was also tested in standard 96 microtiter plates, whereby the results for bacteria and yeasts were confirmed by the fluorescence microscopy. The results were mutually compared for both plankton and biofilms, as well as for plankton and biofilm of the same microorganisms. In no case, the resistance of the planktonic form was higher than the biofilm for the same microorganism. Saccharomyces cerevisiae PMFKG-F7 in the presence of basic color, as well as Rhodotorula mucilaginosa PMFKG-F8 in the presence of the thinner for rinsing paint, shows high sensitivity in planktonic form, whereby the same species are the most resistant in the form of biofilm for the same substances. The highest resistance to all test substances was shown by the biofilm of R. mucilaginosa PMFKG-F8, as well as Candida utilis PMFKG-F9 which was significantly resistant in both tested forms. The obtained results suggest that autochthonous microorganisms that form biofilms can significantly improve the process of removing car paints from the wastewater and being thus new grounds for the development of new biotechnologies.