Electrochemical characterisation of actinorhodin from S. coelicolor culture extracts Perrine Lasserre 1 , Paul A. Hoskisson 2 , Damion K. Corrigan 3 1 University of Strathclyde, UK, 2 Strathclyde Institute of Pharmacy and Biomedical Sciences, UK, 3 Pure and Applied Chemistry, UK When considering pharmaceutically-active compound production, Streptomyces are recognised as the most prolific bacterial genus, responsible for approximately two thirds of all marketed antibiotics and substantial potential for novel molecules through genome mining and engineering. Due to early sequencing of its full genome and the production of pigmented antibiotics, Streptomyces coelicolor A3(2) has been a workhorse strain for investigation of antibiotic biosynthesis and discovery as well as to produce molecules on large scales. Actinorhodin is a blue isochromanequinone produced by S. coelicolor , with a pH-responsive pigmentation, reported redox and organocatalytic activities and therefore suitable features for electrochemical detection. Electrochemical sensors could potentially provide easy, low-cost, rapid and real-time monitoring of actinorhodin production at various scales alongside commonly reported spectrophotometric data. Initially, low bioactivity reports for actinorhodin have not stirred much commercial interest, partly explaining a successful complete synthesis taking 70 years from initial characterisation and a poorly understood mode of action. Without commercially available standards, affinity or catalytic bioreceptors, we explored the possibility of direct detection of actinorhodin and actinorhodin-free culture extracts using voltammetric techniques on gold, carbon and platinum electrodes. Observing inconsistent and rapid fouling of the electrode surface, we subsequently attempted a dual detection approach through combining hyperspectral imaging (HSI) and electrochemical impedance spectroscopy (EIS) to characterise actinorhodin content in small sample volumes. The combined HSI-EIS approach that will be presented builds on a prototype system previously developed to measure the ESKAPE pathogen Pseudomonas aeruginosa (1) . Beyond the real-time snapshot of bacterial metabolic state, developing analysis techniques for this antibiotic means that culture conditions and antibiotic yields can be monitored more closely and high-throughput screening for novel compounds undertaken at lower cost. References 1. Dunphy, R. D., Lasserre, P., Riordan, L., Duncan, K. R. R., McCormick, C., Murray, P., & Corrigan, D. K.(2022).Combining hyperspectral imaging and electrochemical sensing for detection of Pseudomonas aeruginosa through pyocyanin production. Sensors and Diagnostics , 1 (4), 841-850.https://doi.org/10.1039/D2SD00044J
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