Real-time analysis of microbial growth by means of the Heat-Transfer Method (HTM) using Saccharomyces cerevisiae as model organism

In this manuscript, we explore the use of the Heat-Transfer Method (HTM) for the real-time analysis of microbial growth using Saccharomyces cerevisiae as a model organism. The thermal responses of gold electrodes upon exposure to suspensions of S. cerevisiae (wild type strain DLY640) concentrations were monitored, demonstrating an increase in thermal resistance at the solid-liquid interface with higher concentrations of the microorganism. Flow cells were manufactured using 3D-printing to facilitate longitudinal experiments.We can clearly discriminate between the growth of S. cerevisiae under optimal conditions and under the influence of factors that inhibit the replication process, such as the use of nutrient depleted growth medium, elevated temperature, and the presence of toxic compounds. In addition, it is possible to determine the kinetics of the growth process and quantify yeast replication which was demonstrated by measuring a mutant temperature sensitive strain.This is the first time HTM has been used for the real-time determination of factors that impact microbial growth. Thermal sensing is low-cost, offers straightforward analysis and measurements can be performed on-site. Due to the versatility of this method, this platform can be extended to monitor other microorganisms and in particular to study the response of bacteria to selected antibiotics.