Real-time microbial growth curve (RMGC) system: an improved microplate reader with a graphical interface for automatic and high-throughput monitoring of microbial growth curves

Abstract

The study of microbial growth curves is essential for comprehending microbial behavior and enhancing related processes. Current monitoring methods face limitations, including low automation, inefficient detection, and insufficient throughput. To address these challenges, we developed the Real-Time Microbial Growth Curve (RMGC) system, which offers fully automated and high-throughput monitoring of microbial growth through an Improved Microplate Reader (IMR) with a user-friendly graphical interface. By optimizing and calibrating the optical pathways, we achieve high-precision and consistent absorbance detection using LED light sources, surpassing traditional xenon lamp microplate readers, which lack continuous operation capabilities. We validated the RMGC system by cultivating 96 samples of Escherichia coli (E. coli) at a concentration of 10⁵ CFU mL⁻¹. After approximately 12 hours of continuous monitoring, the system exhibited a relative standard deviation (RSD) of less than 3.25% for optical density (OD) measurements and an RSD of 2.52% for the point of inflection (POI). These results indicate a similar level of precision but a longer monitoring time compared to conventional microplate readers, reflecting the effectiveness of the RMGC system in accurately monitoring microbial growth. The RMGC system showcases its versatility through various applications, such as microorganism gradient cultures, anaerobic microbial cultures, and antimicrobial susceptibility testing (AST). Its capabilities have important implications for multiple industries, including pharmaceuticals for antibiotic development, food safety for microbial contamination testing, and microbiological research.