Characterization and Immobilization of a Novel SGNH Family Esterase (LaSGNH1) from Lactobacillus acidophilus NCFM.

Ly Thi Huong Luu Le,Sangeun Jeon,Wanki Yoo,T Doohun Kim,Kyeong Kyu Kim

doi:10.3390/ijms21010091

Abstract

The SGNH family esterases are highly effective biocatalysts due to their strong catalytic efficiencies, great stabilities, relatively small sizes, and ease of immobilization. Here, a novel SGNH family esterase (LaSGNH1) from Lactobacillus acidophilus NCFM, which has homologues in many Lactobacillus species, was identified, characterized, and immobilized. LaSGNH1 is highly active towards acetate- or butyrate-containing compounds, such as p-nitrophenyl acetate or 1-naphthyl acetate. Enzymatic properties of LaSGNH1, including thermal stability, optimum pH, chemical stability, and urea stability, were investigated. Interestingly, LaSGNH1 displayed a wide range of substrate specificity that included glyceryl tributyrate, tert-butyl acetate, and glucose pentaacetate. Furthermore, immobilization of LaSGNH1 by crosslinked enzyme aggregates (CLEAs) showed enhanced thermal stability and efficient recycling property. In summary, this work paves the way for molecular understandings and industrial applications of a novel SGNH family esterase (LaSGNH1) from Lactobacillus acidophilus.

Highlights

Lipolytic enzymes such aslipases or esterases, which are present throughout three domains of life (Eukarya, Bacteria, and Archaea), are generally involved in the hydrolysis of lipids or their derivatives [1,2,3]
Sequence analysis revealed that LaSGNH1 had a molecular mass of ~21 kDa with a single polypeptide chain of 188 amino acids, with a pI of 5.93
LaSGNH1 was shown to be a member of family II lipases/esterases, which is further subdivided into clade I and clade II subfamilies [25]

Summary

Introduction

Lipolytic enzymes such as (phospho)lipases or esterases, which are present throughout three domains of life (Eukarya, Bacteria, and Archaea), are generally involved in the hydrolysis of lipids or their derivatives [1,2,3] They share similar structural and catalytic features, including a highly conserved catalytic triad (Ser-Asp/Glu-His), an α/β hydrolase fold, broad substrate specificity, and an absence of cofactors [4,5]. SGNH family esterases have attracted interest because they are highly useful for the preparation of aromas, flavors, drug intermediates, and pharmaceutical products [8,9,10] They are characterized by four conserved sequence blocks of I–III and V in their primary sequences [8,9]. A number of SGNH family esterases have been identified and characterized from several microorganisms [11,12,13,14,15,16,17,18,19], but there are very few reports in lactic acid bacteria

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Conclusion