Microbial growth laws present simple equations relating the growth
rate of an organism to the limiting nutrient concentration. Since
their introduction by Jacques Monod in the 1940's, growth laws have
been intensely researched, where a major challenge remains to explain
these laws from underlying first principles. Before the advent of
high-throughput sequencing technologies, which also form the basis for
the construction of genome-scale metabolic network models, microbial
growth was often described by so-called "black box" models, in which
metabolism was described by global, "macrochemical" equations. A
consistent thermodynamic theory has been developed around these black
box models in the second half of the 20th century, which seems to have
been largely forgotten by 21st century metabolic modellers. Here, we
show that black box models are still highly useful and often possess
similar predictive powers as far more complex whole-genome models,
while their explanatory powers, and thus their potential to gain new
insight into basic principles, are far superiour due to their extreme
simplicity. We outline a few attempts to integrate the thermodynamic
theory behind black box models into modern genome-scale modelling
approaches. We envisage that such integration will form the basis for
a sound thermodynamic theory of microbial growth, and help
understanding the fundamental thermodynamic limits of microbial
growth.