Sustainable pretreatment method of lignocellulosic depolymerization for enhanced ruminant productivity using laccase protein immobilized agarose beads

Laccase, the selectively lignin degrader, vital to the initiation of lignocellulosic deconstruction was immobilized onto activated agarose beads to increase its reuse potential. Laccase cross-linked beads (~ 3.42 mm) recorded a specific activity of 23 Umg^{- 1}, retaining about 80.43% enzyme activity after 45 days of storage. The immobilization yield and efficiency were 89% and 97% respectively. The equilibrium data fitted the Freundlich equation (R² = 0.9987) demonstrating multilayer adsorption and the presence of Cu, Fe, and S in the elemental analysis of immobilized beads established effective binding between activated agarose beads and the laccase protein. Characterization studies of the immobilized laccase-treated crop residues revealed significant differences in the lignin polymer after each treatment cycle. An increase in digestibility of 26.21% and 7.62% was observed in paddy and finger millet-treated straws respectively, over the controls corroborating efficient lignin depolymerization. The propitious performance of laccase beads authenticated in the batch enzymatic reactor to treat crop residues paves headway as a sustainable green technology in the deconstruction of crop residues for use as ruminant feed, augmenting productivity.