Enzymatic glycerolysis of lignin with Novozym 435: Optimizing biocatalyst reuse for greater efficiency

Lignocellulosic biomass has great potential as a renewable source of valuable chemicals due to its complex chemical composition. Novozym 435 (N435), an immobilized lipase, serves as a biocatalyst in reactions such as transesterification. Such reaction increases the compatibility of lignin in various industrial applications by selectively and efficiently converting this substrate into high-value raw materials. In addition, the efficient reuse of this biocatalyst promotes a more sustainable process in ecological and economic terms, contributing significantly to reducing operating costs and environmental impacts. In this context, this study investigates the potential use of N435, as a biocatalyst in the glycerolysis reaction of lignin to produce lignopolyols. The study focuses on the impact of lignin concentrations on the performance of N435, revealing a significant loss of enzymatic activity at higher lignin contents of 5wt%. The analysis includes enzyme activity assays, optical microscopy, and Fourier Transform Infrared Spectroscopy (FTIR), indicating a detrimental interaction between lignin and N435 over several cycles for concentrations higher than 5wt%. However, lignopolyols produced with 5 wt% lignin showed promising results in the cycles using N435, with a drop-in enzymatic activity, which was expected when the biocatalyst is subjected to adverse conditions but could be used in more batch reactions. The findings emphasize the importance of carefully considering the influence of lignin concentration on enzymatic activity in transesterification reactions, providing valuable information for the sustainable use of lignin in biotechnological processes. The pioneering study explores the reuse of N435 in transesterification reactions involving lignin, suggesting avenues for further research into its application in producing lignopolymers. Therefore, the enzymatic glycerolysis of lignin using N435 is an innovative and essential approach to maximize sustainability in the biochemical industry.