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Braz. j. microbiol ; 42(1): 22-29, Jan.-Mar. 2011. ilus, tab
Artículo en Inglés | LILACS | ID: lil-571370

RESUMEN

Kinetics of a lipase isolated from Bacillus sp. was studied. The enzyme showed maximum activity at pH 9 and temperature 60ºC. The Michaelis constant (K M 0.31 µM) obtained from three different plots i.e., Lineweaver-Burk, Hanes-Wolf and Hofstee, was found to be lower than already reported lipases that confirmed higher affinity of the enzyme for its substrate p-NPL (p-nitrophenyl laurate). Vmax of the enzyme was found to be 7.6 µM/mL/min. Energy of activation calculated from Arrhenius plot was found to be 20.607 kJmol-1. Activation enthalpy (ΔH*) had negative trend and the value for the hydrolysis of p-NPL by the enzyme at optimum temperature was -2.748 kJmol-1 . Activation entropy (ΔS*) and free energy of activation (ΔG*) of the enzyme were found to be 1.468 Jmol-1K-1 and -3.237 kJmol-1, respectively at optimum temperature. Low value of Q10 (0.04788) shows high catalytic activity of the enzyme. Mn2+, Fe2+ and Mg2+ enhanced the lipase activity whereas Cu2+, Na+ and Co2+ inhibited the enzyme activity. However, the enzyme activity was not affected significantly by K+ ions. EDTA and SDS also significantly inhibited the lipase activity. Activity of the enzyme was increased in n-hexane while decreased with increase in concentration of acetone, chloroform, ethanol and isopropanol.


Asunto(s)
Acetona/análisis , Bacillus/enzimología , Bacillus/aislamiento & purificación , Catalasa/análisis , Microbiología Ambiental , Reactivadores Enzimáticos , Curtiembre , Lipasa/aislamiento & purificación , Compuestos Orgánicos , Solventes , Activación Enzimática , Cinética , Métodos , Métodos , Residuos
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