title: Enhanced thermostability of silica-immobilized lipase from Bacillus coagulans BTS-3 and synthesis of ethyl propionate.
abstract: A lipase from the thermophilic isolate Bacillus coagulans BTS-3 was produced and purified. The enzyme was purified 40-fold to homogeneity by ammonium sulfate precipitation and DEAE-Sepharose column chromatography. Its molecular weight was 31 kDa on SDS-PAGE. The purified lipase was immobilized on silica and its binding efficiency was found to be 60%. The enzyme took 60 min to bind maximally onto the support. The pH and temperature optima of immobilized lipase were same as those of the free enzyme, i.e. 8.5 and 55 degrees C, respectively. The immobilized enzyme had shown marked thermostability on the elevated temperatures of 55, 60, 65 and 70 degrees C. The immobilized enzyme was reused for eigth cycles as it retained almost 80% of its activity. The catalytic activity of immobilized enzyme was enhanced in n-hexane and ethanol. The immobilized enzyme when used for esterification of ethanol and propionic acid showed 96% conversion in n-hexane in 12 h at 55 degrees C.
authors.affiliation: Department of Biotechnology, Himachal Pradesh University, Summer Hill, Shimla-171005, India.
authors.forename: Satyendra
authors.initials: S
authors.lastname: Kumar
authors.forename: Shweta
authors.initials: S
authors.lastname: Pahujani
authors.forename: R P
authors.initials: RP
authors.lastname: Ola
authors.forename: S S
authors.initials: SS
authors.lastname: Kanwar
authors.forename: Reena
authors.initials: R
authors.lastname: Gupta
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010168:Palmitates / Q000737:chemistry / Q000378:metabolism; D011422:Propionates / Q000138:chemical synthesis*; D012822:Silicon Dioxide / Q000737:chemistry*; D012997:Solvents; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D010168:Palmitates; D011422:Propionates; D012997:Solvents; C050015:4-nitrophenyl palmitate; D012822:Silicon Dioxide; C069373:ethyl propionate; D008049:Lipase; C428386:thermostable lipase