An Innovative Approach to Immobilize Lipase onto Natural Fiber and its Application for the Synthesis of 2-Octyl Ferulate in an Organic Medium

Lipase catalysis plays a vital role in the synthesis of a variety of compounds of commercial value in food, pharmaceutical as well as in detergent industry. In the present study a commercial lipase, Lipolase T20 was immobilized onto natural fibers of dried coconut fruit by incubating the fiber's bunch in the enzyme solution for 12 h at 8oC. The fiberbound lipase was thereafter treated with 2% (v/v) glutaraldehyde. The fiber-immobilized biocatalyst was optimally active at pH 8.0 and at a temperature of 55oC. The fiber-bound lipase showed maximum hydrolytic activity towards pnitrophenyl palmitate. Among various non-ionic detergents, the exposure to Tween-60 (a non-ionic detergent) enhanced the activity of fiber-bound lipase towards the hydrolysis of p-nitrophenyl palmitate (p-NPP). Among various selected salt ions (1 mM), Al3+, Zn2+, Ca2+, Cu2+ and Fe2+ ions promoted, while Pb2+, Na+, Mn2+ and NH4 + ions decreased the hydrolytic activity of fiber-bound lipase. The immobilized lipase retained more than 45% of its original activity after 5th repetitive cycle of hydrolysis. The immobilized lipase also successfully achieved the esterification of 2-octanol (75 mM) and ferulic acid (100 mM) in DMSO in 3 h at 55oC under shaking at180 rpm.