Lessons learned from Sphingomonas species that degrade abietane triterpenoids

Abietane terpenoid-degrading organisms include Sphingomonas spp which inhab it natural environments and biological treatment systems, An isolate from t he high Arctic indicates that these organisms occur far from trees which sy nthesize abietanes and suggests that some of these organisms can occupy a n iche in hydrocarbon-degrading soil communities, Abietane-degrading Sphingom onas spp provide additional evidence that the phylogeny of this genus is in dependent of the catabolic capabilities of its members. Studies of Sphingom onas sp DhA-33 demonstrate that biological treatment systems for pulp mill effluents have the potential to mineralize abietane resin acids, On the oth er hand, these studies indicate that some chlorinated dehydroabietic acids are quite recalcitrant. Strain DhA-33 grows relatively well on some chlorin ated dehydroabietic acids but transforms others to stable metabolites, Usin g strain DhA-33, a novel method was developed to measure the metabolic acti vity of an individual population within a complex microbial community, Olig onucleotide hybridization probes were used to assay the 16S rRNA:rDNA ratio of DhA-33 as it grew in an activated sludge community. However, this metho d proved not to be sufficiently sensitive to measure naturally occurring re sin acid-degrading populations. We propose that the same approach can be mo dified to use more sensitive assays.