Abstract

Microbioreactor technology is making important advances towards its application in continuous fermentation. Microbioreactors operating in chemostat mode under steady-state conditions can be employed in the characterization of de novo engineered cells. This contribution uses a microchemostat device to characterize the growth of Staphylococcus carnosus, a gram-positive bacterium with relevance for synthetic biology. The microchemostat was critically evaluated by characterizing oxygen mass transfer and mixing and performing a residence time distribution analysis. Mixing times of ~1.2 s, and kLa values of ~92 h-1 were obtained which benchmarks bench scale reactors. Residence time distribution analysis demonstrated operation under nearly ideally mixed conditions with ~ 1% of stagnant volumes, approximating the behaviour of a continuous stirred-tank reactor (CSTR). Microchemostat technology was for the first time used to quantify the specific oxygen uptake rate (sOUR) of Staphylococcus carnosus at two growth conditions. We have therefore developed a microchemostat device that will significantly simplify the phenotypic analysis of de novo engineered strains.