Laccase from Trametes versicolor was immobilized via the formation of interlinking enzyme aggregates (CLEA). Its free and immobilized enzymes were characterized, and its efficiency was tested via the removal of bisphenol A (BPA) in aqueous solution. The resistances against thermal denaturation and pH variations were improved upon immobilization. Although the optimal pH of the enzyme was not modified by immobilization, the latter considerably increased its stability in the pH range of 2.0 to 8.0. The immobilized form was still 50% active after 6 months of storage, while the free form took 1 month to suffer a similar drop in activity. Both free and immobilized T. versicolor laccases were efficient in removing 200 µM BPA from aqueous solutions. The free laccase removed 79% and 92.9% of the compound during the first hour of reaction when 0.1 and 0.2 U were used, respectively. The immobilized form, on the other hand, removed 72% and 94.1% of 200 µM BPA during the first hour of reaction when 0.2 and 0.5 U were used, respectively. The immobilized enzyme allowed seven reuse cycles in the oxidation of ABTS and up to four cycles in the degradation of BPA. The results suggest that the laccase from T. versicolor may be useful in biological strategies aiming at degrading endocrine disruptors, such as BPA.
Substantial amounts of organo-pollutants, often persistent and toxic, are generated globally each year, posing a threat to soil, water, groundwater, and air. The pollutants encompass a wide range of substances from various sources, which include solid as well as liquid ones, such as landfill leachates and wastewaters. The compounds include paper and pulp mill byproducts, pharmaceuticals, diverse types of plastics, hydrocarbons, pigments, and dyes, as well as pesticides and insecticides. Fungal bioremediation stands out as a promising technology that uses the metabolic potential of fungi to eliminate or mitigate the impact of pollutants. Notably, species of the genus Pycnoporus exhibit significant capabilities for degrading a broad spectrum of toxic molecules. This degradation is facilitated by released ligninolytic enzymes, especially laccase, and cellular enzymes pertaining to the cytochrome P450 monooxygenase system. The laccase, which is overproduced by the genus Pycnoporus, is quite remarkable for its high redox potential. The objective of this review is to highlight the proficiency of the Pycnoporus genus in the degradation of pollutants in submerged and solid-state fermentation. Recent studies conducted over the past decade consistently highlight the Pycnoporus genus as a robust contender in the realm of white biotechnology.
The immobilization of a laccase from Pycnoporus sanguineus UEM-20 via the formation of cross-linked enzyme aggregates (CLEAs) was optimized through a central composite design (CCD) of response surface methodology (RSM). Both free and immobilized enzymes were investigated for their physico-chemical characteristics, and their adequacy in removing bisphenol A (BPA) and decolorizing malachite green dye in solution was evaluated. The immobilization caused only minor differences in thermostability. Upon immobilization, the enzyme experienced some changes in its kinetic properties. The Vmax decreased by a factor of 1.1, and the KM increased by a factor of 1.89. These kinetic changes did not modify in any remarkable way the capacity of the immobilized enzyme in degrading BPA and decolorizing malachite green dye. Its sensitivity to NaCl was also minimally affected by immobilization. However, its sensitivity to sodium sulfate was substantially decreased. After 1 month’s conservation, the activity of the free form had suffered a drastic drop. The immobilized form, by contrast, remained 100% active after 6 months. All these findings predict that the immobilized laccase from P. sanguineus UEM-20 may be useful in the enzymatic bioremediation of pollutants such as endocrine disruptors and synthetic dyes.
Fungal laccases are promising oxidative enzymes for bioremediation applications, particularly in the degradation of synthetic dyes present in industrial effluents. Here, we evaluated the inhibitory effects of sodium chloride (NaCl) and sodium sulfate (Na2SO4) on the activity of Trametes versicolor laccase and its ability to decolorize Congo Red (CR), Malachite Green (MG), and Remazol Brilliant Blue R (RBBR). Enzyme assays revealed concentration-dependent inhibition, with IC50 values of 0.22 ± 0.04 M for NaCl and 1.00 ± 0.09 M for Na2SO4, indicating stronger inhibition by chloride. Kinetic modeling showed mixed-type inhibition for both salts. Despite this effect, the enzyme maintained significant activity: after 12 h, decolorization efficiencies reached 95 ± 4.0% for MG, 88 ± 3.0% for RBBR, and 75 ± 3.0% for CR, even in the presence of 0.5 M salts. When applied to a mixture of the three dyes, decolorization decreased only slightly in saline medium (94.04 ± 4.0% to 83.43 ± 5.1%). FTIR spectra revealed minor structural changes, but toxicity assays confirmed marked detoxification, with radicle length in lettuce seeds increasing from 20–38 mm (untreated dyes) to 41–48 mm after enzymatic treatment. Fungal growth assays corroborated reduced toxicity of treated dyes. These findings demonstrate that T. versicolor laccase retains functional robustness under ionic stress, supporting its potential application in saline textile wastewater remediation.