Immobilization of Thermophilic Lipase on Lignocellulosic Sugarcane Bagasse Carrier and Its Biocatalytic Properties

This study investigated the potential of sugarcane bagasse, pretreated with deep eutectic solvents (DES) and modified through oxidation and grafting techniques, as a carrier material for the immobilization of Geobacillus thermocatenulatus lipase (GTL2). The biochemical properties of the immobilized enzyme were evaluated to assess its efficiency in enzyme loading. The results demonstrated that DES pretreatment effectively removed inorganic salts and impurities from sugarcane bagasse, achieving lignin and hemicellulose removal rates of 36.48%±2.66% and 43.28%±0.37%, respectively, while preserving 62.76%±0.56% of the cellulose. The modified carrier exhibited high efficiency in immobilizing GTL2, with enzyme loading efficiencies of 84.96%±0.23% and 63.76%±0.22%, and immobilized enzyme activities of 24.42±1.12 U/mg and 33.58±0.69 U/mg, respectively. Under optimal reaction conditions (60 ℃, pH8.0, Tris-HCl buffer), the immobilized GTL2 demonstrated excellent tolerance to organic solvents such as methanol, ethanol, and glycerol. After storage at −20 ℃ for 14 days, the enzyme retained 84.04%±1.42% of its initial activity, and the relative activity was still above 40% after 7 cycles of reuse. This study highlights the significant potential of sugarcane bagasse as a lignocellulosic carrier for enzyme immobilization and provides valuable insights for the development of novel loading carriers derived from agricultural and forestry waste.