Lipase production from Bacillus safensis VC-6 isolated from the Volcanic Region of Copahue: Optimization and functional genomic insights

Valeria Luisa Foronda^1,2Valeria Castellanos¹Claudia Hoepfner^1,2Daniel Guzmán¹Hector Orlando Guzman¹Jerry Luis Solis Valdivia^1*

• ¹Centro de Biotecnología, Facultad de Ciencias y Tecnología, Universidad Mayor de San Simón, Cochabamba, Bolivia
• ²GEMA Center for Genomics, Ecology and Environment, Faculty of Interdisciplinary Studies, Univesidad Mayor, Santiago, Chile

Extremophilic microorganisms produce highly stable and industrial-grade enzymes with enhanced performance. Thermostable lipases are of great industrial interest due to their stability and efficacy under harsh conditions, making them ideal for applications in biotechnology, pharmaceuticals, and cosmetics. Optimization studies remain limited for lipases sourced from halotolerant bacteria, such as Bacillus safensis VC-6, known to grow above 10% (w/v) NaCl and 50 °C. The limited research on these enzymes prevents their widespread adoption in industries. This study optimized the production of lipases using the extremophilic strain VC-6, isolated from samples from the Copahue Volcano, Chile. Strain VC-6 was selected from twelve candidate strains due to its facile growth within simple culture media and superior potential for lipase production. Growth conditions were optimized using a heterotrophic medium supplemented with 2% (w/v) NaCl, 2% (v/v) glycerol, and pH 6 at 37 °C. Lipase production was maximized based in the basal medium supplemented with 1% (w/v) yeast extract, 0.5% (w/v) KCl, 3% (v/v) sunflower oil, 2% (v/v) glycerol, and pH 8 at 37 °C. Extracellular lipase activity was assessed, and enzyme recovery was facilitated through precipitation methods. Lipase activity was quantified in a batch bioreactor achieving a maximum enzymatic activity of 12.83 U mL-1 at 16 h of cultivation, correlated with the exponential growth phase of the bacteria. Genetic identification confirmed that strain VC-6 belongs to the Bacillus genus, sharing 99.93% similarity with Bacillus safensis. Genomic analysis revealed the presence of key genes related to lipase production, including YtpA (phospholipase), LipC (germination lipase), and a thermostable monoacylglycerol lipase (MAG). These genes likely explain the observed peaks of enzymatic activity during the fermentation process, with distinct activity observed at different times. This study highlights the potential of Bacillus safensis VC-6 as a promising source of thermostable and halotolerant lipases. The integration of optimized bioprocess conditions and genomic-based understanding establishes a solid groundwork for the future industrial exploitation of these biocatalysts under extreme environmental conditions. The optimization of growth conditions and the identification of critical genes related to lipase production further enhance the potential for scaling up production processes in biotechnological applications.