Biochemical and in-silico structural assessments of an acinetobacter haemolyticus lipase KV1 isolated from an oil palm mill effluent

Abstract

The use of microbial enzymes as biocatalysts for a myriad of commercial processes are currently trending owing to their versatility and, their use is considerably greener than the chemically-assisted methods. In this regard, this study reports the comprehensive biochemical characterization of a lipase from novel Acinetobacter haemolyticus KV1 bacteria. The intracellular lipase was purified to ~3.5-fold using consecutive treatments of ammonium sulfate precipitation, dialysis and DEAE-cellulose ion exchange chromatography. The purified lipase exhibited maximum relative activity at 40°C and pH 8.0, respectively. Lipase KV1 was significantly activated (p < 0.05) in reactions supplemented with metal ions, Na+, Ca2+, K+ and Mg2+ (112– 128%) as well as surfactants, Tween 20–80 (110–143%). The lipase hydrolyzed a wide range of oils with tributyrin (140%) being the preferred ones. Reducing (PMSF, DTT, β-mercaptoethanol) and chelating (EDTA) agents significantly inhibited the lipase (p < 0.05) and, significant inhibition was also evident for Triton-X100, SDS, SLS and CTAB (p < 0.05). Interestingly, lipase KV1 retained its relative activities at > 50% for up to 24 h for pH between pH 7-11. Therefore, the full characterization of lipase KV1 reported in this study deserves scientific and economic considerations.