Date of Award

Spring 1982

Project Type


Program or Major


Degree Name

Doctor of Philosophy


The Propionibacterium species possess several attributes that would allow them to survive in an estuarine ecosystem. This investigation is concerned with the distribution and survival of the Propionibacterium sp. in the Great Bay Estuary at New Hampshire. To aid in the enumeration of propionibacteria, a selective medium was developed that demonstrated greater than 99.9% selectivity from skin samples. Failure to detect propionibacteria from water, sediment, fish, and shellfish prompted an investigation into factors that may influence survival. Temperature appears to be the major factor affecting the Propionibacterium's ability to establish a niche. An increase in salinity had a stimulatory effect on the animal strains, resulting in shorter generation times. Conversely, an increase in salinity caused an increase in the generation time of the dairy isolate; yield, however, was not affected. The propionibacteria's ability to tolerate the concentrations of salts found in seawater may have significant industrial implications. One of the problems facing industrial fermentations is the requirement for large amounts of fresh water; converting fermentations to seawater, without detrimental effects, would eliminate much of the water availability problems facing the fermentation industry.