Application of a protic ionic liquid/lignin mixture from sugarcane pretreatment as a supporting agent for the...

In this study, sugarcane straw pretreatment liquor, the residual fraction from biomass pretreatment containing protic ionic liquid and lignin, was used for the immobilization of Eversa® Transform 2.0 lipase via alginate entrapment. In its wet form, liquor beads (BLw) achieved a high value of mechanical strength (7.98 ± 0.73 N), immobilization yield (96.81 %) but negligible recovered activity, whereas freeze-dried (BL) reached 76.84 % yield, 24.37 % recovered activity, and 1153 U g^-1 enzymatic activity. BL showed higher thermal resistance, greater tolerance to alkaline pH, and longer half-life than free enzyme (FL) and lipase immobilized in freeze-dried beads without liquor (BO). Circular dichroism and fluorescence spectroscopy analyses also indicated gains in enzyme thermal resistance and catalytic performance, due conformational changes coming from liquor incorporation during immobilization compared to absence of liquor. Overall, this study demonstrated that the use of sugarcane pretreatment liquor for lipase immobilization has the potential to add value to this industrial residue and improve key parameters for a biocatalyst, providing significant benefits for environmental sustainability as well as industrial bioprocess efficiency.