Culturing the Uncultured: Risk versus Reward

Isolation of new microorganisms is challenging, but cultures are invaluable resources for experimental validation of phenotype, ecology, and evolutionary processes. Although the number of new isolates continues to grow, the majority of cultivars still come from a limited number of phylogenetic groups and environments, necessitating investment in new cultivation efforts. While most microbiologists probably agree that axenic cultures have great value, we need to collectively put our money where our mouth is. I propose that we examine cultivation from the perspective of expected value to rationally incorporate risks and rewards of isolating new microbes. If we can even broadly constrain the cultivation probability and relative values of isolates, we can use this information to evaluate and improve experimental design. There are numerous scenarios for which isolation projects have positive expectations and therefore represent a sound investment.