Efficient and cost-effective biodegradation of phenolic compounds in lignocellulosic biomasses using laccase immobilized onto magnetically recoverable nanocellulose-functionalized iron-oxide nanoparticles

The laccase enzyme is considered as a highly effective catalyst with extensive applications in lignin degradation and sustainable energy production from lignocellulosic biomass. This study presents a novel approach for the degradation of phenolic compounds found in the structure of lignocellulosic biomasses by using laccase immobilized on the surface of nanocellulose-functionalized magnetic nanoparticles (Fe3O4@NC@Enz). The synthesis of this nanobiocatalyst was confirmed through various characterization techniques. Under optimal immobilization conditions, incubation time of 8 hours and enzyme concentration of 2 mg/mL, an impressive immobilization yield of 93.26 % and a relative activity of 90.32 % were achieved. The immobilized laccase demonstrated a storage stability of 68.9 % of its initial activity over a 60-day storage period and exhibited superior stability to that of the free enzyme under various pH and temperature conditions. This study investigated the application of Fe3O4@NC@Enz for degrading phenolic compounds, achieving a notable degradation rate of 84.74 % of the total polyphenol content in the lignin structure while retaining 72.4 % of its catalytic activity after 12 reuse cycles. The immobilized laccase was also effective in both delignification and detoxification of corncob, reaching rates of 72 % and 86.69 %, respectively, after 12 hours of incubation. In conclusion, the findings underscore the effectiveness of the Fe3O4@NC@Enz to improve enzyme stability, activity, and reusability, offering a promising approach for the efficient delignification and detoxification of lignocellulosic biomasses.