Catalytic activity of Candida rugosa lipase immobilized on lignocellulosic wastes: Effect of support material

This study investigates the immobilization of lipase from Candida Rugosa on lignocellulosic wastes derived from rice husk, brewer's spent grain, hemp tea waste, green tea waste, vine bark, and spent coffee grounds, focusing on the characterization of these materials and their impact on the lipase-support interaction. The wastes were subjected to meticulous characterization by ATR-FTIR, BET, and SEM analysis, besides lignin content and hydrophobicity determination. Investigation of parameters influencing immobilization performance revealed the importance of morphology, textural properties and especially hydrophobic interactions which resulted in positive correlations between surface hydrophobicity and lipase immobilization efficiency. Hemp tea waste and spent coffee grounds demonstrated superior immobilization performances (7.20 U/g and 8.74 U/g immobilized activity, 102.3% and 33.5% efficiency, 13.4% and 15.4% recovery, respectively). Moreover, they demonstrated good temporal stability (100% and 92% residual activity after 120 days, respectively) and a complete preservation of immobilized activity after five reuses in the hydrolysis of p-nitrophenyl palmitate in hexane.In addition, the study of enzymatic desorption caused by ionic strength and detergent treatments indicated mixed hydrophobic and electrostatic interactions in rice husk, vine bark, and spent coffee grounds supports, while for hemp tea waste and green tea waste hydrophobic interactions dominated.