A LABORATORY BIOFILM GENERATOR ADAPTABLE FOR RECIRCULATORY OR FLOW-THROUGH OPERATION

A continuous culture system is described which allows the production a nd study of organisms within and released from biofilm. The system ens ured rapid growth of biofilm by exploiting planktonic bacteria using a recirculation technique. The design also included a facility for swit ching to a flow-through arrangement allowing the measurement of biofil m-derived planktonic organisms. Flow rates were governed so that no ch ange in medium velocity was experienced in regions where biofilm accum ulated. When inoculated with bacterial isolates from tap water a subst antial biofilm was rapidly produced as illustrated by scanning electro n microscopy. A clear difference in concentrations of planktonic bacte ria upstream and downstream of the biofilm generator tank was found. T his was due to the release of bacteria from the biofilm in the tank in to the bulk liquid medium. The biofilm generator system was successful ly operated for periods of up to 3 months.