Spatial microbial diversity of the bioremediation system at day 127 as revealed by 16S-23S RISA of the biofilm and liquid-phase communities. The community marker (CM) consists of a mixture of the separately amplified ISR PCR products of the initially prevalent strains (Spi3, Spi4, Elb2, Kon12, Ibu8, I3F1, and Bro12). The present strains exhibited one to four bands, but only one band per strain (indicated with thick arrows) was diagnostically used for community analysis. Nondiagnostic bands are indicated with fine arrows. The numbers at the size marker (SM) bands indicate sizes in base pairs. 1s, bioreactor carrier-bound biofilm 1s (near inflow); 2s, bioreactor carrier-bound biofilm 2s; 3s, bioreactor carrier-bound biofilm 3s; 4s, bioreactor carrier-bound biofilm 4s (near outflow); 1L, bioreactor liquid-phase sample 1L (near inflow); 2L, bioreactor liquid-phase sample 2L; 4L, bioreactor liquid-phase sample 4L (near outflow); BioE, bioreactor effluent; CfE, carbon filter effluent.