Swine manure slurry is a very complex microbial ecosystem because the microbial community evolves from many different sources (e.g., intestinal tract, soil, water, feed); and the decomposition of the waste and ensuing odor problem involves the concerted activities of numerous bacterial species. While research has attempted to characterize the distinctive odor by identifying the odorous metabolites found in swine slurry, there is virtually no information on the bacterial species involved in odor production. Because of this lack of information, our efforts to remediate the odor problem are either unsuccessful or equivocal. Although production of these chemicals is the result of a dynamic microbiological activity, little is known about the specific types of microorganisms responsible for their production. Current cultivation techniques for isolating bacteria are estimated to recover only 1% of the total population in a complex ecosystem, thus other techniques must be used to characterize the microbial community, and identify the bacterial species responsible for producing the odors in swine slurry. The bacterial species responsible for destroying odorous metabolites in swine slurry are also unknown except for a few bacterial species. The phylogenetic analysis of microbial diversity, using 16S rDNA and PCR, has been used to study complex ecosystems, such as activated sludge, marine sediment and gut. This technique has not been used to study the microbial diversity in swine waste slurry.
Odor emanating from anaerobic lagoons and swine production facilities has increased the tension among rural neighbors and among urban and rural residents. Storage of swine waste is associated with the production of a variety of odorous chemicals including ammonia, organic acids, alcohol, and sulfides. Much of this problem is due to the incomplete digestion process associated with anaerobic systems. In addition, production of odorous compounds within a confined swine facility can pose health problems to both the animals and human workers. Although production of these chemicals is the result of microbiological activity, little is known about the types of microorganisms responsible for their production. The results of this research are expected to provide new fundamental knowledge on the microbial population of stored swine manure slurry. Application of this information should result in the development of new approaches for the microbiological control of odor production.
