Monitoring of phenolic compounds in the food industry and for environmental and medical applications has become more relevant in recent years. Conventional methods for detection and quantification of these compounds, such as spectrophotometry and chromatography, are time consuming and expensive. However, laccase biosensors represent a fast method for on-line and in situ monitoring of these compounds. We discuss the main transduction principles. We divide the electrochemical principle into amperometric, voltammetric, potentiometric and conductometric sensors. We divide optical transducers into fluorescence and absorption. The amperometric transducer method is the most widely studied and used for laccase biosensors. Optical biosensors present higher sensitivity than the other biosensors. Laccase production is dominated by a few fungus genera: Trametes, Aspergillus, and Ganoderma. We present an overview of laccase biosensors used for the determination of phenolic compounds in industrial application

Black Sigatoka is a disease that occurs in banana plantations worldwide. This disease is caused by the hemibiotrophic fungus Pseudocercospora fijiensis, whose infection results in a significant reduction in both product quality and yield. Therefore, detection and identification in the early stages of this pathogen in plants could help minimize losses, as well as prevent the spread of the disease to neighboring cultures. To achieve this, a highly sensitive SPR immunosensor was developed to detect P. fijiensis in real samples of leaf extracts in early stages of the disease. A polyclonal antibody (anti-HF1), produced against HF1 (cell wall protein of P. fijiensis) was covalently immobilized on a gold-coated chip via a mixed self-assembled monolayer (SAM) of alkanethiols using the EDC/NHS method. The analytical parameters of the biosensor were established, obtaining a limit of detection of 11.7 µg mL−1, a sensitivity of 0.0021 units of reflectance per ng mL−1 and a linear response range for the antigen from 39.1 to 122 µg mL−1. No matrix effects were observed during the measurements of real leaf banana extracts by the immunosensor. To the best of our knowledge, this is the first research into the development of an SPR biosensor for the detection of P. fijiensis, which demonstrates its potential as an alternative analytical tool for in-field monitoring of black Sigatoka disease.

The biodegradation of organic compounds present in water at trace concentration has become a critical environmental problem. In particular, enzymatic oxidation by fungal laccases offers a promising alternative for efficient and sustainable removal of organic pollutants in water. In this work, the biocatalytic ability of laccases from the Pycnoporus sanguineus CS43 fungus was evaluated. A filtered culture supernatant (laccase cocktail) evidenced an enhanced biotransformation capability to remove common endocrine-disruptor compounds (EDCs), such as bisphenol A, 4-nonylphenol, 17-α-ethynylestradiol and triclosan. A biodegradation of around 89–100 % was achieved for all EDCs using synthetic samples (10 mg L−1) and after the enzymatic treatment with 100 U L−1 (50.3 U mg −1). The biodegradation rates obtained were fitted to a first order reaction. Furthermore, enzymatic biocatalytic activity was also evaluated in groundwater samples coming from northwestern Mexico, reaching biotransformation percentages between 55 and 93 % for all tested compounds. As far as we know this is the first study on real groundwater samples in which the enzymatic degradation of target EDCs by a laccase cocktail from any strain of Pycnoporus sanguineus was evaluated. In comparison with purified laccases, the use of cocktail offers operational advantages since additional purification steps can be avoided.

In this study, the bioelectrocatalytic reduction of molecular oxygen by two highly thermostable laccase isoforms from a native strain of Pycnoporus sanguineus CS43 were evaluated and compared to commercially available laccase from Trametes versicolor (TvL). The laccase isoforms (LAC1 and LAC2) and TvL laccase were immobilized by orientation onto anthracene-modified multiwalled carbon nanotubes (AC-MWCNT), which were subsequently immobilized onto carbon nanofiber mat electrodes fabricated using a carbon MEMS (C-MEMS) process. The performances of the isoforms were evaluated at differing pHs, temperatures, and with various inhibitors under hydrodynamic and hydrostatic conditions. Both LAC1 and LAC2 had onset potentials of over +650 mV vs Ag/AgCl at pH 4.0, which are among the highest reported to date for any laccase bioelectrode. High current densities were also obtained, producing 825 ± 88 μA/cm 2 and 1220 ± 106 μA/cm 2 with LAC1 and LAC2, respectively. The bioelectrodes also demonstrated remarkable operational ranges in pH and temperature as well as increased resistance to common laccase inhibitors. In both cases, they maintained over 70% of their maximum current densities after 12 h of continuous operation at 20 °C and over 20% of their maximum current densities after 6 h of continuous operation at 45 °C. In comparison, the TvL cathodes maintained 50% of their maximum current densities after 12 h at 20 °C and lost all catalytic activity after 2 h at 45 °C. The high stability, onset potential, current densities, and increased inhibitor resilience demonstrated by the results of this study make these isoforms very attractive for applications such as biofuel cell cathodes.

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