Bacterial Growth Rate and Growth Yield: Is There A Relationship?

Abstract

In microbial ecology and physiology, growth rate and growth yield are among the most fundamental parameters. The question whether the two are independent of each other or correlated in some way has been addressed by two schools of microbiologists with contradicting outcomes. After the classical Monodian assumption of constant growth yield was found unsupported, microbial physiologists predicted a positive rate-yield correlation. This was based on the assumption of constant maintenance energy. On the other hand evolutionary biologists predicted a rate-yield trade-off subject to differential selective pressures in different environments. Such a trade-off can explain the wide variation in growth rates and growth yields across the microbial world. However, empirical approaches to the question are plagued by methodological problems and inconsistencies across studies. We critically evaluate the alternative ways of thinking highlighting on selective forces, mechanisms shaping the relationship and appropriate experimental approaches.