Detection of methyl salicylate using bi-enzyme electrochemical sensor consisting salicylate hydroxylase and tyrosinase

• Published in: Biosensors & bioelectronics 2016-11, Vol.85, p.603-610
• Main Authors: Fang, Yi, Bullock, Hannah, Lee, Sarah A., Sekar, Narendran, Eiteman, Mark A., Whitman, William B., Ramasamy, Ramaraja P.
• Format: Article
• Language: English
• Subjects: Agaricales - chemistry; Agaricales - enzymology; Biosensing Techniques - methods; Biosensor; Biosensors; Cascade chemical reactions; Cloning, Molecular; Electrochemical Techniques - methods; Enzymes, Immobilized - chemistry; Enzymes, Immobilized - genetics; Enzymes, Immobilized - metabolism; Escherichia coli - genetics; Limit of Detection; Markers; Methyl salicylate; Mixed Function Oxygenases - chemistry; Mixed Function Oxygenases - genetics; Mixed Function Oxygenases - metabolism; Models, Molecular; Monophenol Monooxygenase - chemistry; Monophenol Monooxygenase - metabolism; Nanotubes, Carbon - chemistry; Plant diseases; Plants (organisms); Plants - chemistry; Plants - metabolism; Pseudomonas putida - chemistry; Pseudomonas putida - enzymology; Pseudomonas putida - genetics; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Salicylate hydroxylase; Salicylates; Salicylates - analysis; Salicylates - metabolism; Transducers; Tyrosinase; Volatile compounds; Volatile organic compound
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2016.05.060

Volatile organic compounds have been recognized as important marker chemicals to detect plant diseases caused by pathogens. Methyl salicylate has been identified as one of the most important volatile organic compounds released by plants during a biotic stress event such as fungal pathogen infection. Advanced detection of these marker chemicals could help in early identification of plant diseases and has huge significance for agricultural industry. This work describes the development of a novel bi-enzyme based electrochemical biosensor consisting of salicylate hydroxylase and tyrosinase enzymes immobilized on carbon nanotube modified electrodes. The amperometric detection using the bi-enzyme platform was realized through a series of cascade reactions that terminate in an electrochemical reduction reaction. Electrochemical measurements revealed that the sensitivity of the bi-enzyme sensor was 30.6±2.7µAcm−2µM−1 and the limit of detection and limit of quantification were 13nM (1.80ppb) and 39nM (5.39ppb) respectively. Interference studies showed no significant interference from the other common plant volatile compounds. Synthetic analyte studies revealed that the bi-enzyme based biosensor can be used to reliably detect methyl salicylate released by unhealthy plants. •Potentially offer a solution to early detect pest and pathogen infection in crops.•Use bi-enzymatic electrochemical biosensor with carbon nanotubes as transducers.•The basic principles outlined in this work could be extended for other biosensors.