Characteristic study of Candida rugosa lipase immobilized on lignocellulosic wastes: effect of support material

For the frst time is reported the comparison of solid biocatalysts derived from Candida rugosa lipase (CRL) immobilized on diferent lignocellulosic wastes (rice husk, brewer’s spent grain, hemp tea waste, green tea waste, vine bark, and spent cofee 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. Investigating parameters infuencing immobilization performance revealed the importance of morphology, textural properties, and hydrophobic interactions revealed the importance of morphology, textural properties and especially hydrophobic interactions which resulted in positive correlations between surface hydrophobicity and lipase immobilization efciency. Hemp tea waste and spent cofee grounds demonstrated superior immobilization performances (7.20 U/g and 8.74 U/g immobilized activity, 102.3% and 33.5% efciency, 13.4% and 15.4% recovery, respectively). Moreover, they demonstrated good temporal stability (100% and 92% residual activity after 120 days, respectively) and retained 100% of their immobilized activity after fve 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 cofee grounds supports, while hemp tea waste and green tea waste were dominated by hydrophobic interactions.