Isolation and Characterization of Lipase-Producing Bacteria from Oil-Contaminated Soil

Abstract

The study focuses on the isolation and characterization of lipase-producing bacteria from oil-contaminated soil, addressing the growing need for efficient biodegradation processes in polluted environments. Lipases, enzymes that hydrolyze fats into glycerol and free fatty acids, hold significant industrial and environmental applications due to their ability to break down various lipid substrates. This research aimed to identify potent lipase producers from contaminated sites and characterize their enzymatic properties for potential biotechnological applications. Soil samples were collected from various oil-contaminated sites, and standard serial dilution and plating techniques were used to isolate bacterial strains. The isolates were screened for lipase activity using tributyrin agar plates, with clear halo zones around bacterial colonies indicating lipase production. Lipase activity was quantified using p-nitrophenyl palmitate (pNPP) as a substrate, and the effects of temperature, pH, and metal ions on enzyme activity and stability were investigated to determine optimal conditions for lipase function. A total of 50 bacterial isolates were obtained, with 10 showing significant lipase activity. The top-performing isolates were identified through 16S rRNA sequencing. The optimal temperature for lipase activity was found to be 37°C, with a pH range of 7.0-8.0 being most favorable. The presence of Ca2+ and Mg2+ ions enhanced enzyme activity, while heavy metals like Hg2+ and Cu2+ inhibited it. The kinetic parameters, including Km and Vmax, were determined for the most promising isolates, indicating a high affinity for lipid substrates. The findings were compared with previous studies, highlighting the superior performance of the isolated strains under various environmental conditions. The characterized lipases show promise for applications in bioremediation, detergent formulation, and the food industry, owing to their stability and activity under diverse conditions. The study successfully isolated and characterized lipase-producing bacteria from oil-contaminated soil, with identified strains exhibiting high enzymatic activity and stability, suggesting their potential for biotechnological applications in pollutant degradation and other industries. Future research should focus on scaling up production and evaluating the in-situ application of these enzymes in contaminated environments.