Population dynamics of a dual - biofilm in a capillary bioreactor.

Most biofilm studies employ single species, yet in nature biofilms exist as mixed cultures, with inevitable effects on growth and development of each species present. To investigate how related species of bacteria interact in biofilms, two spp., and , were cultured in capillary bioreactors and their growth measured by confocal microscopy and cell counting. When inoculated in pure culture, both bacteria formed healthy biofilms within 72 h with uniform coverage of the surface. However, when the bioreactors were inoculated with both bacteria simultaneously, was completely dominant after 48 h. Even when the inoculation by was delayed for 24 h, was eliminated from the capillary within 48 h. It is proposed that production of the lipopeptide putisolvin by is the likely reason for the reduction of . Putisolvin biosynthesis in the dual-species biofilm was confirmed by mass spectrometry.