Properties of a Biocatalyst Based on Immobilized Recombinant Lipase Geobacillus stearothermophilus G3 in Synthesis of Methyl Esters of Fatty Acids

Abstract

A heterogeneous biocatalyst BCL based on recombinant extracellular lipase of thermophilic bacterium Geobacillus stearothermophilus G3 with the activity of 23,6 act.un./g was prepared by covalent immobilization on aminated silica gel. The influence of the solvent nature, temperature (30–60 °C), proportion of water (1–10 %) and catalyst (0,25–25 %) on the yield of methyl esters of fatty acids (MEFA) was studied in the reaction of methanolysis of sunflower oil over the BCL catalyst. The observed maximal MEFA yield was 43 %. A high operation stability of the catalyst under study was demonstrated: The catalyst kept more than 50 % of its initial activity after 480 h operation (20 cycles) that makes it promising for synthesis of fatty acid esters used for production of biodiesel fuel.