Optimization of a whole-cell cadmium sensor with a toggle gene circuit

• Published in: Biotechnology progress 2009-05, Vol.25 (3), p.898-903
• Main Authors: Wu, Cindy H., Le, David, Mulchandani, Ashok, Chen, Wilfred
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosensing Techniques - methods; Biosensors; Biotechnology; Cadmium - analysis; cadR promoter; Fundamental and applied biological sciences. Psychology; genetic circuits; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Luminescent Measurements - methods; Methods. Procedures. Technologies; P. putida 06909; Promoter Regions, Genetic; Pseudomonas putida - genetics; Pseudomonas putida - metabolism; Psuedomonas putida; Various methods and equipments; whole-cell cadmium sensor
• ISSN: 8756-7938; 1520-6033
• DOI: 10.1002/btpr.203

This work demonstrates improvement of a whole‐cell cadmium detection sensor through construction of a gene circuit. A cadmium (II) specific regulatory promoter, PcadR, from Psuedomonas putida 06909, is used in the assembly of a toggle circuit. The circuit contains the cadR promoter fused to lacIq and gfp, and a divergently transcribed tac promoter and cadR. The toggle sensor exhibits lower background fluorescence, and a 20‐fold lower detection limit in comparison to a nontoggle gene circuit. The detection limit of the toggle sensor is 0.01 μM (1.12 ppb) cadmium chloride, and tunable with the addition of isopropyl‐b‐D‐thiogalactopyranoside (IPTG). The toggle sensor is highly specific to cadmium (II), and no response is elicited from zinc, lead, manganese, nickel, copper, and mercury. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009