Use of electrical resistance tomography (ERT) for the detection of biofilm disruption mediated by biosurfactants

Inline measurement of biofilms could provide a valuable technology for water, food and bioprocessing industries to improve quality control and avoid contamination. This study presents the first use of electrical resistance tomography (ERT) to detect the removal of biofilms in a pipe. It also tests the effectiveness of sophorolipids and rhamnolipids for the disruption of Bacillus subtilis BBK006 biofilms in an industrial setting. Biofilms were grown on the inner side of a section of 1.5″ test pipe for 5 days using nutrient broth as the culture medium. After the medium was removed the test pipe was incorporated into a cleaning test circuit for the biofilm disruption experiment, where water, sophorolipids (0.4 g L−1) or rhamnolipids (0.4 g L−1) solutions were pumped through respectively for 30 min. ERT was used as an indirect evaluation of the film disruption progression. A cleaning parameter was identified based on zonal boundary averages which successfully measured the extent of biofilm removal.