Glutaraldehyde activation of polymer Nylon-6 for lipase immobilization: Enzyme characteristics and stability
ABSTRACT An extracellular alkaline lipase of a thermo tolerant Bacillus coagulans BTS-3 was immobilized onto glutaraldehyde activated Nylon-6 by covalent binding. Under optimum conditions, the immobilization yielded a protein loading of 228 microg/g of Nylon-6. Immobilized enzyme showed maximum activity at a temperature of 55 degrees C and pH 7.5. The enzyme was stable between pH 7.5-9.5. It retained 88% of its original activity at 55 degrees C for 2h and also retained 85% of its original activity after eight cycles of hydrolysis of p-NPP. Kinetic parameters Km and Vmax were found to be 4mM and 10 micromol/min/ml, respectively. The influence of organic solvents on the catalytic activity of immobilized enzyme was also evaluated. The bound lipase showed enhanced activity when exposed to n-heptane. The substrate specificity of immobilized enzyme revealed more efficient hydrolysis of higher carbon length (C-16) ester than other ones.
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ABSTRACT: This study aimed to develop an optimal continuous process for lipase immobilization in a bed reactor in order to investigate the possibility of large-scale production. An extracellular lipase of Pseudozyma hubeiensis (strain HB85A) was immobilized by adsorption onto a polystyrene-divinylbenzene support. Furthermore, response surface methodology (RSM) was employed to optimize enzyme immobilization and evaluate the optimum temperature and pH for free and immobilized enzyme. The optimal immobilization conditions observed were 150 min incubation time, pH 4.76, and an enzyme/support ratio of 1282 U/g support. Optimal activity temperature for free and immobilized enzyme was found to be 68°C and 52°C, respectively. Optimal activity pH for free and immobilized lipase was pH 4.6 and 6.0, respectively. Lipase immobilization resulted in improved enzyme stability in the presence of nonionic detergents, at high temperatures, at acidic and neutral pH, and at high concentrations of organic solvents such as 2-propanol, methanol, and acetone.01/2012; 2012(2090-0406):329178. DOI:10.1155/2012/329178
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ABSTRACT: Lipases (triacylglycerol acylhydrolases; E.C. 220.127.116.11) constitute a group of enzymes defined as carboxylesterases that catalyse the hydrolysis (and synthesis) of long-chain acylglycerols at the lipid–water interface. In this study, a novel method has been developed to prepare nanoprotein particles carrying lipase using a photosensitive microemulsion polymerization process. The nanostructured lipases with photosensitive features have been characterized by transmission electron microscopy (TEM) and Zeta Sizer. The average particle size of nanolipases was found to be about 100nm. Lipase nanoparticles were used in hydrolysis of paranitrophenyl palmitate (p-NPP) and the results were compared with free lipase. The parameters like pH, temperature and hydrolytic activity that affect p-NPP hydrolysis were investigated by using lipase nanoparticles and compared to free lipase. Lastly, reusability of lipase nanoparticles was investigated and according to our results, this novel lipase nanoparticles showed admirable potential in reusable catalyst.Process Biochemistry 08/2011; 46(8):1688-1692. DOI:10.1016/j.procbio.2011.04.011 · 2.52 Impact Factor
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ABSTRACT: Flavor esters are an important kind of flavor compounds, which are widely used in the food and pharmaceutical fields. The recombinant CS-2 lipase was immobilized after purification for which kieselguhr showed 18.5% of binding efficiency with 150.7 U/g of lipase activity. The immobilized lipase was used for the synthesis of butyl acetate in n-heptane. The factors affecting the synthesis of butyl acetate were investigated in the study. The results showed that the conversion of 98.2% was achieved under the following condition: reaction time (10 h); water activity (0.02); reaction temperature (55℃ ℃ ℃ ℃); the concentration of acetic acid and n-butanol (0.1 mol/L and 0.2 mol/L); the addition of 4 Å molecular sieve (0.5 g) at 8h of reaction time. The conversion of substrate decreased only from 98.2% to 87.4% after five cycles in use of the immobilized lipase.