The distribution of alginate genes encoding biosynthesis of alginate w
as examined for bacterial isolates associated with corrosive biofilms
recovered from source water, cooling lines, and reactor surfaces of a
nuclear power plant. A total of 120 diverse Gram-positive and -negativ
e isolates were obtained. Using DNA:DNA hybridization, 11 isolates wer
e shown to contain sequences homologous to structural (algD, algC, alg
-76) and/or regulatory (albB) alginate biosynthetic genes derived from
an alginate-producing cystic fibrosis isolate of Pseudomonas aerugino
sa (FRD1). Identification of isolates was accomplished by fatty acids
methyl esters (FAME) analysis and the Biolog identification system. Ni
ne of the twelve isolates were identified as various Pseudomonas spp.,
and two additional Gram-negative isolates were tentatively identified
as Aeromonas veronii and Stenotrophomonas maltophilia. The remaining
isolate was identified as a Gram-positive Bacillus pumilus. The result
s of the investigation extend current knowledge on the distribution of
alginate biosynthetic genes in environmental isolates and permits the
development of a more environmentally realistic model system to inves
tigate the role of exopolymer production in biofilm formation and bioc
orrosion processes.