Synthesis, characterization and application of lipase-conjugated citric acid-coated magnetic nanoparticles for ester synthesis using waste frying oil

Abstract

In the present work, magnetic nanoparticles (MNPs) were prepared by chemical precipitation of trivalent and divalent iron ions which were functionalized using citric acid. The bacterial isolate KX781317 was isolated from oil-contaminated site. The isolate produced lipase, which was purified and immobilized on magnetic nanoparticles (MNPs) for ester synthesis from waste frying oil (WFO). The characterization of MNPs employed conventional TEM, XRD and FTIR techniques. TEM analysis of MNPs showed the particle size in the range of 20-50 nm. FTIR spectra revealed the binding of citric acid to FeO and lipase on citric acid-coated MNPs. The citric acid-coated MNPs and lipase-conjugated citric acid-coated MNPs had similar XRD patterns which indicate MNPs could preserve their magnetic properties. The maximum immobilization efficiency 98.21% of lipase-containing citric acid-coated MNPs was observed at ratio 10:1 of Cit-MNPs:lipase. The pH and temperature optima for lipase conjugated with Cit-MNPs were 7 and 35 °C, respectively. Isobutanol was found to be an effective solvent for ester synthesis and 1:2 ratio of oil:alcohol observed significant for ester formation. The ester formation was determined using TLC and the % yield of ester conversion was calculated. The rate of ester formation is directly proportional to the enzyme load. Formed esters were identified as isobutyl laurate ester and isobutyl myristate ester through GC-MS analysis.

Adsorbed leucaena protein on citrate modified Fe3O4 nanoparticles: synthesis, characterization, and its application as magnetic coagulant

“…Furthermore, citric acid modified iron oxide nanoparticles has shown affinity for immobilize protein, enzymes, drugs, etc. [24][25][26][27][28][29].…”

Magnetic transfection with superparamagnetic chitosan-loaded IGFBP5nanoparticles and theirin vitrobiosafety

“…The surface of carboxylated modified SPIONPs was rich in carboxyl groups and can be recombined with amino-rich chitosan in the form of covalent bond. In many studies, chlorosulfonic acid supported piperidine-4-carboxylic acid (PPCA) [ 34 ], citric acid [ 27 , 28 ], PEG [ 35 ], oleic acid [ 36 ] and polyamide acid [ 37 ] were used to modify SPIONPs to make its surface touch carboxyl groups, which can be combined with different substances to show different functions. In our study, citric acid-modified SPIONPs were successfully prepared by chemical coprecipitation method.…”

“…The three-necked flask was then placed in a water bath at 85°C. A total of 20 ml ammonium hydroxide was added with a dropping funnel; the addition was completed within 10 min, and stirring was continued for another 30 min [ 27 , 28 ]. The resulting suspension was centrifuged at 8500 r.p.m.…”

Microbial lipase production: A deep insight into the recent advances of lipase production and purification techniques

“…The esterification process of dihydroxyl‐stearic acid via lipases obtained from Rhizomucor meihei and C. antarctica [30] etc. Lipase obtained from Staphlococcus aureus , immobilized on magnetic nanoparticles, has also been employed for the synthesis of ester using frying oil waste [31].…”