Synthetic metabolic transducers in Saccharomyces cerevisiae as sensors for aromatic permeant acids and bioreporters of hydrocarbon metabolism

Abstract

Yeast-based biosensors have great potential for various applications, although the present range of detectable chemicals is still very minimal. This work provides an enlargement of the knowledge on detectable chemicals and creates an additional basis for engineering modular yeast biosensors. Bacterial allosteric transcription factors, such as MarR and PdhR, were recruited to build transducer circuits in Saccharomyces cerevisiae. MarR-based biosensors were designed for the detection of aromatic permeant acids (benzoate and salicylate), whereas the PdhR-expressing yeast cells were engineered for responding to pyruvate. In general, all our engineered strains showed a fast response time and a strong fluorescent output signal to chemical concentrations ranging from 5 mM down to 2 fM. They exhibited versatile dynamic range and were capable of operating in a variety of complex media that might contain any of these compounds. A new milestone in biosensor design is the engineering of inter/intracellular metabolic biosensors that would allow real-time monitoring of either the metabolism of particular compounds, or the detection of their intermediate/end products. Our synthetic cells are applicable to different areas, from adequate real-time detection of aromatic permeant acids to regulation/monitoring of different hydrocarbon metabolisms. The new strains engineered in this study could be of great importance because of the ecological significance of aromatic permeant acids from their formations during either hydrocarbon degradation or metabolism of different chemicals to their involvement in different biological and non-biological systems.