Engineered lipase from Janibacter sp. with high thermal stability to efficiently produce long-medium-long triacylglycerols

Abstract

Lipase MAJ1 from Janibacter sp. is an sn-1,3 specific lipase for preparing long-medium-long (LML) type structured triacylglycerols (TAGs), but low optimum reaction temperature limited its application. Based on the structure built with Alphafold2 and MD simulation, we performed mutagenesis on the lid domain. The mutants L171A, A182P and P192C-T100C increased the optimum temperatures by 5 °C, 5 °C and 10 °C, respectively. The combination of three mutations (MAJ1 M4) increased the optimum temperature by 10 °C and a 5.5-fold increase in activity on tricaprylin. The residual activity of MAJ1 M4 was 70% after 60 min incubation at 45 °C, compared to no residual activity determined for MAJ1 wild-type in the same condition. The production of LML with the immobilized lipase MAJ1 M4-catalyzed interesterification was 57.1 mol% in 24 h compared with 44.3 mol% produced by MAJ1 wild-type. Moreover, the immobilized MAJ1 M4 retained 93% productivity after 13 cycles of synthesis. This mutagenesis design would pave the way for the application of MAJ1 in the food industry.