Quantification of a single population in a mixed microbial community using a laser integrated microarray scanner

A laser integrated microarray scanner was used to quantify and compare the biomass of Burkholderia cepacia G4 alone, mixed with Afipia sp., and mixed with a trichloroethylene and phenol degrading community. Samples containing B. cepacia G4 were placed in 3-mm diameter wells on gelatin coated glass slides then fixed and immunofluorescently labeled using an IgG conjugate with an attached Alexa^TM 546 fluorophore. Linearity and sensitivity of the scanner for biomass quantification were established, and a lower detection limit of 2–5 mg L^–1 (10³–10⁴ cells mL^–1) was calculated. Growth of B. cepacia G4 alone and in the presence of the TCE degrading community was measured using the scanner. Results suggest that the microarray scanner can be used to quantify the biomass of a single population in a dense mixed microbial community. Key words: biomass, Burkholderia cepacia G4, fluorescent antibody, microarray scanner, mixed community.