Optimisation of Enzyme Lignin Degradation Using Response Surface Methodology for Sustainable Lignocellulosic By-Products Management

The efficient degradation of lignin from agricultural by-products is a critical step in the development of sustainable bioprocessing technologies for waste valorisation. Enzymatic degradation of kraft lignin performed with lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (Lac) was investigated. A response surface methodology (RSM) based on a Box–Behnken Design (BBD) was employed in order to optimise key process parameters including enzyme concentration, lignin concentration, pH, incubation temperature, and activator concentration. The surface plots were used to determine the best conditions for each enzyme in order to better degrade kraft lignin. Therefore, LiP needed a stronger acidic environment and moderate temperature, MnP needed an almost neutral pH and moderate temperature, and Lac needed a neutral pH and higher temperature. This work contributes to the development of smart agricultural waste management practices by combining enzymatic treatments with statistical modelling for process optimisation. This study provides a framework for lignin degradation that can be used as a starting point for diverse lignocellulosic by-product fragmentation, thus supporting a circular bioeconomy initiative in accordance with today’s trends. The optimised enzymatic parameters could help enhance efficiency, enable process standardisation across feedstocks, and support economically and environmentally sustainable industrial-scale lignin valorisation in integrated biorefineries.