Transformation efficiency and GFP expression in E. coli

Genetic transformation of bacteria is a foundational technique in molecular biology and biotechnology, enabling the introduction and expression of foreign genes for research, industrial, and educational applications. This thesis investigates the transformation efficiency and green fluorescent protein (GFP) expression in Escherichia coli using the pGLO plasmid system, with the primary objective of supporting the development of a graduate-level laboratory course focused on bioprocess engineering and molecular biotechnology. The pGLO plasmid contains a GFP reporter gene regulated by an arabinose-inducible promoter and an ampicillin resistance gene that allows for selective growth of transformed cells. Competent E. coli HB101 K-12 cells were transformed using a calcium chloride-mediated heat shock protocol and subsequently cultured on selective media with and without arabinose. Successful transformation was confirmed qualitatively through bacterial growth on ampicillin-containing agar plates and visualization of GFP expression under ultraviolet illumination. Fluorescent colonies were consistently observed under inducing conditions, indicating effective plasmid uptake and regulated gene expression. Control plates lacking plasmid DNA or arabinose demonstrated expected growth patterns, supporting the validity of the experimental design. Although extensive quantitative measurements of transformation efficiency were limited, the experimental outcomes aligned with established behavior reported in the literature and instructional laboratory standards. This study emphasizes qualitative assessment of transformation success, experimental reproducibility, and biological variability inherent to bacterial gene expression systems. The results demonstrate that the pGLO transformation system functions reliably as a model for future integration into advanced bioprocess and bioengineering curricula.