Idiosyncratic investigation of Trametes versicolor yellow laccase using organic fruit exocarp in solid-state fermentation

The involvement of enzymes to utilize lignocellulosic biomass into biorefinery is often a challenging task. The fruit exocarp—jackfruit, pineapple, and kaffir were utilized for the production of yellow laccase by Trametes versicolor at solid-state fermentation. Laccase, a protagonist enzyme, has a major vital application in biotechnology field. The laccase productivity from jackfruit exocarp was increased from 4.71 to 9.58 U/mL at 25 °C respectively on the twenty-second day, whereas by exocarps of pineapple and kaffir was reduced to 5.72 and 4.91U/mL. The highest enzyme production was performed at an equal molar ratio of inorganic substrates with pH 4, 70% of moisture content at 25 °C. Furthermore, the yellow laccase was purified and obtained 2.23-fold higher than crude enzyme with specific activity as 4.43U/mg. The molecular weight of the purified laccase enzyme was 44 kDa with protein concentration as 83 µg/mL; copper content as 219.1 µg/L, and carbohydrate content with 8% were procured. The laccase activity towards guaiacol substrate was examined by Lineweaver–Burk plot. The kinetic studies of laccase shows K m value of 1.8 mM and V max 4.8 µmol/ml/min. The rate constant k cat was 0.0267 mol L/s and the substrate specificity of the enzyme k cat / K m was 152.44/M/s. The production and the characteristic study of T. versicolor laccase were confirmed by UV spectra and FTIR, which showed stronger intensity at β-sheet than at α-helix. The surface of the fruit exocarps and the laccase enzyme were examined under SEM. This one-step approach of metabolic process the finite resources optimize the productivity, diminish the greenhouse gas emissions, and hence a revolutionary change from the linear economy to circular economy.