Cloning, Expression, and Characterization of GDSL-Type Lipolytic Enzyme Genes from Epidermidibacterium keratini EPI-7 Isolated from Human Skin

TL;DR

This study identifies and characterizes seven new carboxylesterase enzymes from a skin bacterium, showing potential for use in cosmetics and pharmaceuticals due to their stability and activity under industrial conditions.

Contribution

The discovery of novel thermostable, alkaline carboxylesterases from the skin microbiome with industrial application potential.

Findings

The enzymes prefer short-chain fatty acids and are classified as carboxylesterases, a novel finding in the skin microbiome.

They show optimal activity at alkaline pH and high temperatures, with good thermostability.

The enzymes are stable in non-ionic detergents and tolerate organic solvents like methanol and isopropanol.

Abstract

This study investigated seven putative lipolytic enzymes (EstEk01-07) from the skin microbiome bacterium Epidermidibacterium keratini EPI-7, focusing on their properties relevant to industrial applications. Sequence analysis revealed conserved GDSL motifs and four conserved blocks, characteristic of the GDSL/SGNH superfamily, with predicted α/β/α folds consistent with these enzymes. Significant variations in the number of α-helices and β-sheets among the EstEk enzymes suggested diverse substrate specificities and catalytic efficiencies. The enzymes exhibited a strong preference for short-chain fatty acids (C2-C4), classifying them as carboxylesterases, a novel finding within the skin microbiome. Optimal enzyme activity was observed at alkaline pH (8.0-9.0) and thermophilic condition (50-60°C), with substantial thermostability retained after heating at 50°C for three hours. Metal ion analysis revealed a significant stimulatory effect of Ca2+ and Fe3+, while other transition metals were inhibitory. The enzymes were stable in a range of non-ionic detergents, but sensitive to SDS. Moreover, they exhibited notable tolerance to various organic solvents, particularly methanol and isopropanol, suggesting potential applications in cosmetics and pharmaceutical industries. This study identifies a novel library of thermostable, alkaline carboxylesterases from the skin microbiome, highlighting their potential for industrial biocatalysis and further investigation into their role in skin lipid metabolism.

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