Microbial cell quantification.

The cell number of each species within the mixed species biofilm (NX,O) was calculated by equation [15]. E is the amplification efficiency of the reaction, CT,R and CT,X are the threshold cycles (CT) for the reference mixed and unknown mixed cultures, respectively. CFUR are the colony forming units for the reference bacterial cell cultures. VR are the volumes of standard bacterial cell cultures processed for DNA extraction, t is the fold dilution of the unknown mixed cultures, and q is the number of multiple species whose DNA extractions were equally mixed together to serve as the reference mixed culture. The asterisk(*) indicates the mean value of triplicate samples.Microbial cell quantification.