Kinetic and thermodynamic characterization of lipase produced by Cellulomonas flavigena UNP3.

Lipase of Cellulomonas flavigena UNP3 was purified by two-step purification process comprising ammonium sulfate precipitation followed by gel permeation chromatography (GPC). The recovery of lipase after GPC was found to be 1.70% with 20.98-fold increase in specific activity. The molecular weight of lipase protein was found to be 45.2 kDa by SDS-PAGE. Activation energy for p-nitrophenol palmitate (pNPP) hydrolysis was 26.45 kJ mol(-1) , while temperature quotient (Q10 ) was found to be 1.64. The enzyme was found to be stable over wide pH range and thermally stable at 30-40 °C up to 60 min of incubation while exhibited maximum activity at 30 °C with pH 7.0. Vmax , Km , and Kcat for pNPP were found to be 666.71 U ml(-1) , 1.33 mM (pNPP) and 433 min(-1) , respectively. Activation energy for irreversible inactivation Ea(d) of lipase was 64.32 kJ mol(-1) . Thermodynamic parameters of irreversible inactivation of lipase and pNPP hydrolysis were also determined.