Quantification of microbial robustness

Abstract

Stable cell performance in a fluctuating environment is essential for sustainable bioproduction and synthetic cell functionality; however, microbial robustness is rarely quantified. Here, we describe a high-throughput strategy for quantifying robustness of multiple cellular functions and strains in a perturbation space. We evaluated quantifications theory on experimental data and concluded that the mean-normalized Fano factor allowed accurate, reliable, and standardized quantification. Our methodology applied to perturbations related to lignocellulosic bioethanol production showed that Saccharomyces cerevisiae Ethanol Red exhibited both higher and more robust growth rates than CEN.PK and PE-2, while a more robust product yield traded off for lower mean levels. The methodology validated that robustness is function-specific and characterized by positive and negative function-specific trade-offs. Systematic quantification of robustness to end-use perturbations will be important to analyze and construct robust strains with more predictable functions.

Robustness: linking strain design to viable bioprocesses

“…CV can be substituted by the Fano factor, in which the variance of a measured quantity is divided by its mean. The Fano factor is often preferred over the CV because it allows more reliable and standardized quantification [85][86][87].…”