Laccases are industrially relevant enzymes because of their ability to oxidize a wide variety of substrates. At the same time, they play an important role in environmental protection and biosensor development due to their ability to transform many phenolic compounds. Laccase-based sensors are important for water analysis, where they detect the presence of toxic phenolic compounds, and are also used in the food industry to detect antioxidants. By miniaturizing the sensors, we reduce analysis time, reagent costs and waste.
In the present work, the submerged cultivation of the white rot fungi Trametes versicolor, Trametes gibbosa and Dichomitus squalens, which are known producers of extracellular laccase, was studied. Laccase activity in the filtrate of the production medium and its dependence on pH were evaluated. The filtrate with the highest laccase activity was used for the oxidation reaction in the microfluidic system, in which a miniaturized flow spectrophotometric detector and an oxygen microsensor were successfully integrated. The results of in-line measurements of the oxidation product at the outlet of the microreactor were comparable to the measurements in a conventional spectrophotometer, which provides a good basis for further development of a miniaturized laccase-based flow-through biosensor.
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