Production, Characterization and Immobilization of a Fusarium solani Lipase by Chitosan Magnetic Nanoparticles

Abstract

Lipase producing fungus was isolated and identified as a strain of Fusarium solani based on its 18s rDNA sequencet. The enzyme it produces was purified by diethyl amino ethyl sephadex (DEAE-sephadex) column chromatography. The specific activity of the pure enzyme was 1.98 U/mg protein. The kinetics study showed that Km and Vmax values were 0.63µM and 29.4µM/min/mg protein, respectively. The MW was 95.27 kDa. Effects of pH, incubation temperature and organic solvents on the lipase activity were studied. The maximum enzyme activity was obtained at pH 8.5 and incubation temperature 35°C. Hexane and butanol inhibited enzyme activity by 51% and 72.6 %, respectively, while DMSO stimulated the activity by 47.8%. The lipase was immobilized by fusion to chitosan-coated iron oxide magnetic nanoparticles and cross-linked by glutaraldehyde. The reusability and storage period of the immobilized enzyme showed that the enzyme retained 80% of its activity after 15 reuse cycles and retained 97% of activity after 30 days of storage at 4°C. The immobilized lipase was tested for synthesis of sugars-oleate esters and the ester products were analyzed by liquid chromatography tandem-mass spectrometry (LC/MS/MS). This investigation identified the potential for use of the obtained F. solani lipase in industrial applications that utilize organic solvents or alkaline pH values, such as detergent industry.