Submitted to: Microbial Ecology International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: August 22, 2008
Publication Date: N/A
Technical Abstract: Storage of manure from large-scale swine facilities is associated with the microbiological production of a variety of emission and odorous compounds, including ammonia, organic acids and alcohols, and sulfides. One of the more noxious compounds produced is skatole (3-methyl-indole), produced primarily from the degradation of tryptophan. Skatole can also be produced from indole-acetic acid (IAA), which is also a breakdown product of tryptophan. We have been attempting to isolate anaerobic bacteria from stored swine manure capable of producing skatole, from which no isolate has been reported to produce this compound. Aliquots of swine manure slurry were enriched in media containing added tryptophan, and isolates from cultures producing skatole were recovered following streaking on agar plates. No pure cultures were isolated that produced skatole, but when colonies were combined in a mixed culture, some cultures were capable of producing skatole. One combined culture was capable of producing skatole from IAA, but not tryptophan. Analyses of 16S rDNA gene sequences from DNA isolated from combined cultures indicated a minimum of five different species are present in skatole-positive cultures. Many of the species appeared to represent novel or unreported genera/species. While attempts are being made to isolate pure cultures using various media and approaches, the data suggest that skatole production may be a consequence of the actions of two or more bacterial strains, or strains difficult to isolate in pure culture. This research demonstrates the complication that one might encounter in isolating pure cultures of interest for particular biochemical properties.