Zhu_2026_Appl.Microbiol.Biotechnol_110_128

Lipases are versatile biocatalysts widely applied in hydrolysis and synthesis reactions, yet bacterial acidophilic and solvent-tolerant lipases remain poorly characterized. In this study, an acid- and organic solvent-resistant lipase (LipC) and its cognate foldase (LifB) from Burkholderia gladioli Bsp-1 were cloned and heterologously expressed in Escherichia coli. Soluble and catalytically active LipC was obtained only upon co-expression with LifB, demonstrating a strict foldase-dependent folding requirement. Phylogenetic analysis classified LipC as a LipA-type bacterial lipase. Biochemical characterization revealed that LipC exhibited maximal activity at pH 3.5 and showed remarkable stability under acidic conditions, retaining more than 70% of its activity after prolonged incubation at pH 4.0. The enzyme displayed optimal activity at 55 degC and maintained moderate thermal stability. Notably, LipC retained high activity in nonpolar organic solvents, with significant activation observed in n-hexane and cyclohexane. Substrate specificity and kinetic analysis indicated a preference for medium-chain fatty acid esters, with the highest catalytic efficiency toward p-nitrophenyl caprate (C10). Collectively, these results identify LipC as a foldase-dependent bacterial lipase combining acidophilic behavior and solvent tolerance, expanding the current understanding of bacterial lipases and highlighting their potential relevance for biocatalysis under acidic and nonaqueous conditions. KEY POINTS: LipC is a foldase-dependent bacterial lipase requiring LifB for functional expression. LipC exhibits strong acidophilicity with optimal activity at pH 3.5. LipC is highly activated by nonpolar solvents such as n-hexane and cyclohexane.