Abstract
Bacteria are ubiquitous microorganisms that exhibit a diverse array of metabolic capabilities and interact with their environment through molecular signaling processes. They have the ability to perceive and respond to several types of molecules, including micronutrients such as iron, zinc, and copper, as well as quorum sensing molecules such as acyl-homoserine lactones (AHLs), autoinducing peptides (AIPs), and autoinducer-2 (AI-2), which are essential for their growth and survival. Additionally, these organisms possess the capability to degrade or transform pollutants, such as heavy metals and organic compounds, into less toxic derivatives. The aforementioned attributes render microorganisms very attractive candidates for the development of biosensors and bioremediation agents. The use of molecular biology techniques in the manipulation of bacterial genomes holds promise for enhancing their functioning and expanding their scope of utility. This dissertation comprises a series of investigations aimed at addressing various challenges related to biosensing and bioremediation. One strategy includes the use of genetically modified whole-cell bacteria capable of biosensing and reporting bioavailable copper levels.Genetically modified microbes, such as Bacillus subtilis, provide a potentially advantageous solution due to its ability to be manipulated to selectively identify copper in soil, thereby obviating the need for soil extractions and high-cost instrumentation. In a separate effort, a number of biosensors were constructed in order to detect several quorum-sensing peptides produced by B. subtilis. In the last part of this dissertation project, B. subtilis endospore display technology was used to successfully express a heterologous enzyme, L-haloacid dehalogenase (HadL), on the surface of endospores. This strategy was used for the aim of environmental bioremediation, with the particular goal of removing halogenated contaminants like 2-haloacids from contaminated water.