The presence of the phenol gossypol has severely limited the utilization of cottonseed meal and oil in the food and animal feed industries. Highly efficient means of biodegradation of gossypol and an understanding of the cytotoxicity of its degradation products remain outside current knowledge and are of universal interest. In this work, we showed for the first time that laccase can catalyze the intramolecular annulation of the aldehyde and hydroxyl groups of gossypol for the o-semiquinone radical and originate the released ·OH radical. It was further found that the oxidation of aldehyde groups significantly decreases reproductive toxicity and hepatotoxicity. These results indicate a novel detoxification pathway for gossypol and reveal the crucial role played by radical species in cyclization. This discovery could facilitate the development of safe, convenient, and low-cost industrial methods for the detoxification of cotton protein and oil resources.

Secondary metabolites of traditional Chinese herbs can prominently stimulate the production of laccase from white rot fungi during submerged fermentation. However, the molecular mechanism through which these natural products induce the production of laccase remains unknown. In this study, the Chinese herbal medicine Polygonum cuspidatum was used to induce laccase production in Trametes versicolor, and the best inducer was identified in emodin, even under conditions of 1000-L, large-scale fermentation. Proteomics analysis identified a selection of proteins that were differentially expressed in the presence of emodin, indicating that emodin may affect the expression of laccase genes through three mechanisms: reducing bioenergy productivity, the aryl hydrocarbon receptor (AHR)/xenobiotic response element (XRE) pathway, and the nuclear erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway. Combined with protoplast flow cytometry and fluorescence, it is revealed that emodin might reduce the synthesis of ATP by lowering the mitochondrial membrane potential, leading to the subsequent responses.

Naphthalene (Nap) is widely distributed in the environment and has attracted concern due to its recalcitrance to biodegradation and acute toxic effects. Although several laccases can degrade naphthalene, it remains unclear whether laccase is involved in dioxygenation or ring fission of polycyclic aromatic hydrocarbons (PAHs). We demonstrated that laccase has a naphthalene dioxygenase function with a distinct joint approach to oxygen and the alternative regioselective ring-fission process. These results supplement the family of dioxygenase with laccase, a mild method for the ring opening of aromatics, and an operable scale-up application for remediation from PAH pollution and for regioselective oxygenation and ring opening.

The defensive chemical system of Pheropsophus occipitalis has long been a research focus on biomimetic catalysis and energy applications, yet the biosynthetic origin of hydrogen peroxide (H ₂ O ₂ ) in its defensive glands remains unresolved. This work aimed to decipher the underlying catalytic mechanism and develop a novel biomimetic energy supply strategy. Electron paramagnetic resonance (EPR) spectroscopy and molecular docking were employed to verify the radical-mediated pathway of laccase-catalyzed hydroquinone oxidation. Laccase and catalase were co-immobilized on cerium oxide–titanium dioxide composite supports to enhance catalytic stability and efficiency. A biomimetic microchannel catalyst bed coupled with a pulsed cascade booster system was further constructed, inspired by the compartmentalized anatomy of P. occipitalis . We demonstrate for the first time that laccase catalyzes hydroquinone oxidation to generate H ₂ O ₂ via radical intermediates, and reveal a triple synergistic catalytic cycle consisting of oxygen regeneration, hydrogen element turnover, and cerium redox shuttle. The immobilized laccase yields a relative H ₂ O ₂ concentration of 191.79%, corresponding to a 9.2-fold improvement over free laccase. The integrated biomimetic system realizes on-demand in situ generation and utilization of H ₂ O ₂ . This study advances the mechanistic understanding of the P. occipitalis chemical defense system, and provides a novel, low-noise and eco-friendly technical route for the development of portable energy supply systems.