Isolation and characterization of beewax degrading enzymes from the digestive guts of greater wax moth, Galleria mellonella (Lepidoptera: Pyralidae)

Abstract

The greater wax moth, Galleria mellonella (L.) is one of the most destructive honeycomb pests in the world. The digestive gut enzymes, esterase and lipase are a group of enzymes that hydrolytically catalyzes the esters and long-chain fatty acid linkage of wax components of beeswax. Final instar stage larvae were selected and homogenized for enzymes activity assay and subsequent analysis. The enzymes were purified by combination of ammonium sulfate precipitation and gel filtration using Sephadex G-100. The amount of protein and specific activity of lipase were 0.01 ± 0.002 mg/mL and 1.63 ± 0.88 mol/min/mg protein, respectively, with a 163-fold purity and 33.3 percent recovery, while for esterase14.71 ± 1.46 and 11.23 ± 1.41 mol/min/mg protein, respectively, with a 1.97-fold purity and 34.383 percent recovery. Furthermore, biochemical characterization esterase and lipase were carried out through testing its activities
against factors, such as different temperatures and pH ranges with the use of p-nitrophenyl butyrate (PNPB) p-nitrophenyl palmitate substrates. The highest activities of enzymes were determined at the temperature ranges of 35–40 °C and pH ranges of 7–9.Insect pest damage to agricultural products can be reduced by using inhibitors against digestive enzymes. The findings of this research establish the role of esterase and lipase in the physiological function of G. mellonella in the degradation of beeswax and developing novel inhibitors against these enzymes can be implemented to control G. melonella. Isolation, purification, and characterization of esterases and lipases from the guts of G. mellonella could be a crucial step toward a better understanding of their action and the establishment of a safe and effective control method for G. mellonella as well as other insect pests.