Energy budget model for bacterial growth and shape maintenance

Like any other living organisms, micron-sized bacteria grow and thrive in diverse environments by efficiently allocating energy resources to growth, metabolism, shape maintenance and proliferation. To understand how a bacterium regulate its growth rate, cell shape and size in different environmental conditions, we develop a mechanistic model based on the budgeting of energy contributions for key cellular functions: nutrient import into the cell, energy expended for growth, cellular metabolism, shape maintenance and energy loss due to dissipation. In this framework, optimizing the rate of assimilation of physiological energy translates into optimizing cellular fitness for proliferation. This energy allocation theory allows us to uncover the feedback motifs for cellular adaptive response to chemical, mechanical, and thermal perturbations. By calibrating model parameters with available experimental data for the model organism E. coli, we quantitatively predict the growth and morpho dynamics of E. coli in different environmental perturbations induced by nutrient shifts, temperature changes and osmotic shocks.