Longevity of bacteria: Considerations in environmental release

Microbial growth theory has been developed primarily for laboratory culture. With increased opportunity for release of beneficial organisms, including those that have been genetically engineered, into the environment, it is important to understand microbial behavior under natural conditions in which there is usually severe nutrient limitation. By investigation of the survival of three beneficial soil bacteria in distilled water, the surprising observation was made of cell longevities in excess of a year without substrate input. It is suggested that this could result from the utilization of dead cells within the population and from the viable cells' having a very low maintenance energy requirement, thus placing the cell in a state of arrested metabolism.