Thermostable Lipase from Geothermal Thermophiles: Biochemical Characterization and Industrial Application Potential

Thermophilic lipase-producing microorganism’s present important industrial benefits owing to their stability and catalytic activity under extreme environmental conditions. This study sought to isolate and somewhat purify thermostable lipases from thermophilic bacteria collected from geothermal soils in (Hajj Yousef and Qaymawa, Iraq). A total of 68 samples were collected from hot springs at various depths and analyzed for lipase production utilizing tributyrin agar. Promising isolates were identified as Bacillus subtilis, Bacillus thermoleovorans, and Acidithiobacillus ferrooxidans. The lipase enzyme was purified using ammonium sulfate precipitation trailed by size-exclusion chromatography, yielding a 12-fold purification with 65% recuperation. SDS-PAGE revealed a single protein band of ~35 kDa. The enzyme exhibited optimum activity at 70°C and pH 9.0 and retained 85% activity at 80°C and in alkaline pH. Kinetic analysis showed a Km of 2.1 mM and Vmax of 120 U/mg. The enzyme demonstrated substrate specificity toward olive oil and stability in methanol, Ca2+, and SDS. Application trials confirmed 92% conversion of used oil to biodiesel and 80% fat degradation in wastewater. These findings highlight the enzyme's potential in sustainable biotechnology.