Characterisation of Acid Protease-Producing Bacterium Micrococcus luteus from the Pitcher Fluid of Nepenthes distillatoria L.

Abstract

Nepenthes distillatoria L., a carnivorous plant endemic to Sri Lanka, produces pitcher fluid, rich in digestive enzymes. Despite its apparently hostile conditions, the pitcher fluid harbours a diverse and unique microbial community. In this study, bacteria were isolated from the open pitcher fluid of N. distillatoria collected at two sites in distinct locations in Kalawana, Rathnapura district, in Sri Lanka. From twelve samples, twenty-four bacterial isolates were obtained and subjected to acid-protease enzyme assay using an agar plate method. Relative enzymatic activity was quantified for all the isolates that produced positive results. Notably, one isolate displaying significant acid protease activity was identified as Micrococcus luteus based on 16S rRNA sequence analysis. Therefore, this study revealed the pitcher fluid of N. distillatoria supports a distinct bacterial community with potential industrial applications, highlighting its value as a promising source for bioprospecting.