INTERACTIONS OF 1 MU-M LATEX-PARTICLES WITH PSEUDOMONAS-AERUGINOSA BIOFILMS

Fluorescently labelled latex microbeads were used to study the interac tion of particles with Pseudomonas aeruginosa biofilms in a continuous flow annular reactor. Beads were readily distinguished and enumerated in both intact and disaggregated biofilm samples. The fraction of bea ds that attached to biofilm during a 24 h period ranged from 0.001 to 0.01 and was proportional to biofilm cell carbon and to the standard d eviation of biofilm thickness. Microbeads added to biofilm of steady s tate thickness (30 mum) were observed to be located throughout the ent ire biofilm depth in 24 h. Many of the microbeads that attached to bio film shortly after bacterial inoculation (thickness of 2 mum) remained near the substratum as cells grew past and covered them. Microbeads w ere observed near the biofilm substratum interface for up to 5 days af ter bead addition. Beads formed aggregates on biofilms, but not in bul k water. Beads captured by biofilm remained in the reactor system long er than beads that never attached to biofilm.