Analysis of a 2,4,6-trichlorophenol-dehalogenating enrichment culture and isolation of the dehalogenating member Desulfitobacterium frappieri strain TCP-A
A. Breitenstein et al., Analysis of a 2,4,6-trichlorophenol-dehalogenating enrichment culture and isolation of the dehalogenating member Desulfitobacterium frappieri strain TCP-A, ARCH MICROB, 175(2), 2001, pp. 133-142
An anaerobic, 2,4,6-trichlorophenol ortho-dehalogenating mixed culture was
enriched from sediment of the river Saale (Germany). Two isolated dechlorin
ating colonies (MK1 and MK2) consisted of rods of different lengths and thi
cknesses, indicating heterogeneity. Following subcultivation with thiosulfa
te as alternative electron acceptor and cocultivation with Clostridium cele
recrescens(T), the 2,4,6-trichlorophenol-dehalogenating bacterium Desulfito
bacterium frappieri strain TCP-A was isolated and characterized regarding i
ts taxonomic properties and the spectrum of chlorophenols that it dehalogen
ated. Four other bacterial strains were coenriched and identified as organi
sms with closest phylogenetic relatedness to the Clostridium type strains C
. indolis, C. glycolicum, C. hydroxybenzoicum and C. sporosphaeroides (16S
rDNA sequence identities of 99.5, 99.2, 94.4, and 93.5%, respectively). Amp
lified ribosomal DNA restriction analysis of the original dehalogenating cu
ltures MK1 and MK2 (when not exposed to thiosulfate) confirmed the microbia
l heterogeneity and revealed the presence of two additional species related
to the type strains of C. celerecrescens and Clostridium propionicum. Only
one copy of the 16S rRNA genes of Desulfitobacterium frappieri in each of
the clone libraries of MK1 and MK2 (containing 136 and 56 clones, respectiv
ely) was found by dot-blot hybridization, suggesting a relatively low numbe
r of the dehalogenating bacterium within the enrichment culture.