A Comparative In Silico Analysis of Bacterial Lipases: Thermostability, Solvent Tolerance, and Kinetic Profiles Across Geobacillus, Pseudomonas, and Bacillus

Background: Bacterial lipases (EC 3.1.1.3) are pivotal biocatalysts widely used in non-aqueous synthesis and biodiesel production. However, enzyme instability in demanding industrial conditions remains a major challenge. While the catalytic profiles of specific lipases have been well-characterized in vitro, a systematic comparative analysis of these parameters across different bacterial genera is currently lacking.

Methods: To address this gap, we conducted an in silico study using the BRENDA database to investigate structural-functional relationships across three major industrial genera: Geobacillus, Pseudomonas, and Bacillus. We systematically identified and analyzed quantitative parameters, including Michaelis constants (K_m), temperature and pH optima, and solvent stability profiles.

Results: Our analysis revealed a significant inverse relationship between structural stability and catalytic flexibility. Thermophilic Geobacillus lipases (optimal temperature 68–80°C; pH 7.5–9.0) demonstrated remarkable tolerance to organic solvents, often exhibiting hyperactivation (e.g., reaching 149.6% and 142.5% relative activity in 1-dodecanol and n-heptadecane, respectively). In contrast, mesophilic Pseudomonas lipases (optimal temperature 45–60°C; pH 6.0–9.0) were highly sensitive to solvent-induced inactivation, indicated by rapid half-life decay (e.g., just 0.19 days in 1,5-pentanediol). Furthermore, kinetic profiling of Bacillus lipases highlighted substrate-dependent variability, with K_m values shifting significantly from 0.62 mM to 22 mM. This indicates that the structural rigidity required for thermotolerance and solvent stability constrains substrate affinity in non-aqueous media.

Conclusion: This study establishes a computational pipeline for the targeted selection of lipases. By integrating macroscopic conditions (temperature/pH) with solvent stability and kinetic properties, our findings offer practical guidelines for engineering and employing lipases in industrial bioprocesses.