BACKGROUND Ionic liquids (ILs) have been used as additives to immobilise lipase from a new source of Bacillus sp. (ITP‐001) by the physical adsorption method supporting green poly(3‐hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) in order to evaluate the influence of the cationic core ([C4mpy]Cl, [C4min]Cl), of anions ([C4min]Cl, [C4min]N(CN)2, [C4min]Tf2N) and the cation chain length ([C2min]Tf2N, [C4min]Tf2N)) in the immobilization process. The immobilized biocatalysts (IB) were characterized with regard to morphological and physico‐chemical properties, and total activity recovery yield (Ya) and biochemical properties of more efficient IB were evaluated. RESULT Total activity recovery yield (Ya) for the immobilized biocatalysts employing LI as additives always resulted in higher values compared with the control. The most efficient was using the more hydrophobic IL [C4min]Tf2N, which represents a 2‐fold greater increase in the recovery of enzymatic activity. It retained more than 73% of its original activity after 20 reuses compared with the control, which, after ten cycles, retained only 33% of its original activity. CONCLUSION The anions and the cation chain length of ionic liquids have a strong influence on the immobilization process. The results for biocatalyst immobilized with [C4min]Tf2N showed an increase in total activity recovery yield and considerable improvement in operational stability. © 2014 Society of Chemical Industry