Perspectives of aminoacylases in biocatalytic synthesis of N-acyl-amino acids surfactants

Abstract

Many industrial processes are performed using harmful chemicals. The current technical synthesis of N-acyl-amino acids relies on acyl chlorides, which are typically obtained from phosgene chemistry. A greener alternative is the application of whole cells or enzymes to carry out synthesis in an environmentally friendly manner. Aminoacylases belong to the hydrolase family and the resolution of racemic mixtures of N-acetyl-amino acids is a well-known industrial process. Several new enzymes accepting long-chain fatty acids as substrates were discovered in recent years. This article reviews the synthetic potential of aminoacylases to produce biobased N-acyl-amino acid surfactants. The focus lays on a survey of the different types of aminoacylases available for synthesis and their reaction products. The enzymes are categorized according to their protein family classification and their biochemical characteristics including substrate spectra, reaction optima and process stability, both in hydrolysis and under process conditions suitable for synthesis. Finally, the benefits and future challenges of enzymatic N-acyl-amino acid synthesis with aminoacylases will be discussed. KEY POINTS: • Enzymatic synthesis of N-acyl-amino acids, biobased surfactants by aminoacylases.

Keywords: N-acyl-amino acids; Aminoacylase; Biobased surfactants; Biocatalysis; Green chemistry.

Fig. 1

Exemplified structures of amino acid surfactants. A N-myristoyl-L-glutamate; B N-oleyl sarcosinate; C Diels–Alder adduct of myrcene, maleic acid and L-serine (Jolmes et al. 2024); D N-lauroyl-L-arginine ethyl ester (LAE); E O-lauryl glycinate; and F ε-N-lauroyl-L-lysine (Koreishi et al. 2009a)

Fig. 2

A Principal comparison of amide and ester synthesis utilizing amino acids or alcohols; B synthetic routes towards N-acyl-L-amino acids. Route 1: Chemical synthesis using coupling agents or chlorine chemistry; route 2: cellular systems employing activated fatty acids and route 3: in vitro biocatalytic approaches using either reverse hydrolysis or aminolysis; (R₁ = amino acid side groups, R₂ = CoA or ACP, R₃ = H or adenylate, R₄ = miscellaneous chemical activating groups and R₅ = alcohols like methanol or glycerol, P_i/AMP, inorganic phosphate/adenosine monophosphate). Processing details and responsible enzymes are described in the main text

Fig. 3

Phylogenetic tree of aminoacylases and relevant homologues. The alignment was generated with the Clustal Omega algorithm (Sievers et al. 2011) and displayed by average distance. To the enzymes acronyms their NCBI accession number, PDB- or UniProt identifiers are added (Haeger 2023). Acy3: murine aminoacylase-3 (UniProt: Q91XE4); Acy2, human aminoacylase-2 or aspartoacylase (UniProt: P45381); HmrA, peptidase from Staphylococcus aureus (PDB: 3RAM); Ama, aminoacylase from Geobacillus stearothermophilus (Uniprot P37112); ILR1, IAA-amino acid hydrolase from Arabidopsis thaliana (UniProt_P54968); CsAga, alpha-glutamine aminoacylase from Corynebacterium striatum Ax20 (UniProt_Q8GGD4); PepV, beta-Ala-Xaa dipeptidase from Lactobacillus delbrueckii (UniProt_P45494); CPG2, carboxypeptidase G2 from Pseudomonas sp. RS-16 (UniProt_P06621); ArgE, acetylornithine deacetylase from E. coli (UniProt: P23908); HiDapE, succinyl-diaminopimelate desuccinylase from Haemophilus influenzae (accession number: WP_005693818); L-ACY-1, aminoacylase 1 from Heliothis virescens (GenBank: AET43034); pAcy1, porcine aminoacylase-1 (accession number: NP_999061); hAcy1, human aminoacylase-1 (accession number: NP_000657); PM20D1, human N-fatty-acyl-amino acid hydrolase (UniProt: Q6GTS8); MsAA, aminoacylase from Mycolicibacterium smegmatis MKD8 (GenBank: AWT55079); SmAA, aminoacylase from Streptomyces mobaraensis (GenBank: BAI44523); SamAA, aminoacylase from Streptomyces ambofaciens ATCC 23877 (GenBank: AKZ54783); SgAA, aminoacylase from Streptomyces griseus (accession number: WP_003970135); PmAcy, aminoacylase from Paraburkholderia monticola (GenBank: KXU85199); BurkAcy, aminoacylase from Burkholderia sp. LP5_18B (GenBank: BBI47489); Sgx9260b, amidohydrolase (PDB: 3MKV); Sgx9260c, prolidase (PDB: 3N2C); IADA, isoaspartyl dipeptidase from E. coli (UniProt P39377) (Haley 1968); SmELA, epsilon-lysine acylase from S. mobaraensis (accession number: WP_004948872); SamELA, epsilon-lysine acylase from S. ambofaciens (accession number: WP_053127917); ScELA, aminoacylase from S. coelicolor A3 (GenBank: CAB61667.1); SgELA, epsilon-lysine acylase from S. ambofaciens (accession number: WP_069631407)