ExcEllEnt StabIlIty and SynthEtIc actIvIty of lIpaSE from B. stearothermophilus mc7 ImmobIlIzEd on tIn dIoxIdE In EnvIronmEntally frIEndly mEdIum

A thermostable lipase from B. strearothermophilus MC7 was stabilized via immobilization on nanostructured tin dioxide (nanoSnO 2 -MC7). The synthetic activity of nanoSnO 2 -MC7 in two ionic liquids containing chloride anions was assessed. In the presence of 3-methyl-1-octyl imidazolium chloride, the stearyl stearate production proceeded at a much higher reaction rate than in solvent-free medium and 95 % conversion of the substrates was achieved for 5 h at 65 °C. Our results showed that it also had a beneficial effect on the operational and thermal stability of the immobilized lipase MC7. In this green solvent, the biocatalyst was almost fully active after eight synthetic cycles and up to 60 % of the initial activity of nanoSnO 2 -MC7 lipase was preserved after long heating at 75 oC.