ISOLATION, CHARACTERIZATION, AND COMPARISON OF BACTERIA FROM SWINE FECES AND MANURE STORAGE PITS

Authors: Cotta, Michael; Whitehead, Terence; Zeltwanger, Rhonda

Submitted to: Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2003
Publication Date: 7/1/2003
Citation: COTTA, M.A., WHITEHEAD, T.R., ZELTWANGER, R.L. ISOLATION, CHARACTERIZATION, AND COMPARISON OF BACTERIA FROM SWINE FECES AND MANURE STORAGE PITS. ENVIRONMENTAL MICROBIOLOGY. 2003. V. 5. P. 737-745.

Interpretive Summary: Storage of swine manure is associated with the microbiological production of a variety of odorous chemicals including ammonia, organic acids and alcohols, and sulfides. Because odor emission from livestock creates a nuisance and therefore may be regulated, there is considerable interest in devising methods to control these emissions. Although a microbiological process, little is known about the types of microorganisms present in stored manure. In the current study, the most numerous bacteria were isolated from stored manure, identified, and some important characteristics determined. The major bacteria isolated were found to be related to known bacteria, but few could be identified as known species. All strains formed products that have been associated with odor, although few produced ammonia or degraded protein and amino acids. More selective procedures may be required to isolate these organisms thought to be the most important in production of odorous emissions. The information gathered will be useful in directing future examinations of the ecology of manure storage. This will help guide the development of methods to intervene in the production of odors associated with swine.

Technical Abstract: Storage of swine manure is associated with the microbiological production of a variety of odorous chemicals including ammonia, organic acids and alcohols, and sulfides. In order to determine the role of individual microorganisms in the production of odor causing chemicals, representative strains of microorganisms were isolated from feces and stored manure slurry, identified, and physiologically characterized. For manure slurry samples, total anaerobe colony counts were greatest when a non-selective, habitat simulating medium containing clarified swine slurry was used, whereas the highest counts for fecal anaerobes were obtained on rumen fluid containing medium. Fecal and slurry samples were also plated onto the appropriate medium containing the antibiotics tetracycline, erythromycin, and tylosin (5 ug/ml, individually) and the proportional counts of organisms capable of growing in the presence of these antibiotics determined. Randomly selected isolates from the highest dilutions were identified by 16s rDNA sequence analysis, and selected physiological characteristics were determined. The results of these examinations indicate that the predominant culturable microorganisms from these environments are obligately anaerobic, low mol % G+C bacteria who are members of Clostridial, Eubacterial, and Lactobacillus/Streptococcus phylogenetic groups. Isolates similar to Sporomusa and Flexibacter/Cytophaga/Bacteroides (CFB) groups were also obtained. Although similar overall, fecal and slurry samples differed in bacterial composition. Manure slurry samples were dominated by organisms similar to Clostridium coccoides and Enterococcus species, while the distribution of species present in feces appeared much broader. While most of the pure cultures could be assigned to known phylogenetic groupings, few could be identified as known species. Examination of some growth and physiological characteristics of fecal and slurry isolates showed these to be primarily carbohydrate fermenters, although some were able to ferment lactate and amino acids. When the ability of manure and fecal isolates to ferment protein, peptides, and amino acids was examined, a relatively small percentage of these were able to do so and most of these fermented carbohydrates in addition to the amino acid sources provided. The predominant amino acid fermenters were most closely related to C. coccoides and C. botulinum, but representatives of the Bacteroides, Staphylococcus, Enterococcus, and other phylogenetic groups were also found. The results reported here are compared with those obtained from clones libraries prepared from the same environmental samples as well as those of others.