title: Comparative study of thermostability and ester synthesis ability of free and immobilized lipases on cross linked silica gel.
abstract: A novel support has been utilized for immobilization of lipase, which was prepared by amination of silica with ethanolamine followed by cross linking with glutaraldehyde. Lipases from Rhizopus oryzae 3562 and Enterobacter aerogenes were immobilized on activated silica gel, where they retained 60 and 50% of respective original activity. The thermal stability of the immobilized lipases was significantly improved in comparison to the free forms while the pH stability remained unchanged. E. aerogenes and R. oryzae 3562 lipases retained 75 and 97% of respective initial activity on incubation at 90 degrees C, whereas both the free forms became inactive at this temperature. The conversion yield of isoamyl acetate was found to be higher with the immobilized fungal (90 vs. 21%) and bacterial lipases (64 vs. 18%) than the respective free forms. Immobilized R. oryzae 3562 lipases retained 50% activity for isoamyl acetate synthesis up to ten cycles whereas it was eight cycles for E. aerogenes.
authors: Microbial Biotechnology and Downstream Processing Laboratory, Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur, West Bengal, 721302, India.
authors: Annapurna
authors: A
authors: Kumari
authors: Paramita
authors: P
authors: Mahapatra
authors: Garlapati Vijay
authors: GV
authors: Kumar
authors: Rintu
authors: R
authors: Banerjee
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D021902:Enterobacter aerogenes / Q000201:enzymology*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004951:Esterification; D004952:Esters / Q000138:chemical synthesis*; D005782:Gels / Q000737:chemistry; D008049:Lipase / Q000737:chemistry*; D012233:Rhizopus / Q000201:enzymology*; D012822:Silicon Dioxide / Q000737:chemistry*; D013045:Species Specificity; D013696:Temperature
chemical_list: D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D004952:Esters; D005782:Gels; D012822:Silicon Dioxide; D008049:Lipase