title: A novel thermoalkalostable esterase from Acidicaldus sp. strain USBA-GBX-499 with enantioselectivity isolated from an acidic hot springs of Colombian Andes.
abstract: Several thermo- and mesoacidophilic bacterial strains that revealed high lipolytic activity were isolated from water samples derived from acidic hot springs in Los Nevados National Natural Park (Colombia). A novel lipolytic enzyme named 499EST was obtained from the thermoacidophilic alpha-Proteobacterium Acidicaldus USBA-GBX-499. The gene estA encoded a 313-amino-acid protein named 499EST. The deduced amino acid sequence showed the highest identity (58 %) with a putative α/β hydrolase from Acidiphilium sp. (ZP_08632277.1). Sequence alignments and phylogenetic analysis indicated that 499EST is a new member of the bacterial esterase/lipase family IV. The esterase reveals its optimum catalytic activity at 55 °C and pH 9.0. Kinetic studies showed that 499EST preferentially hydrolyzed middle-length acyl chains (C6-C8), especially p-nitrophenyl (p-NP) caproate (C6). Its thermostability and activity were strongly enhanced by adding 6 mM FeCl3. High stability in the presence of water-miscible solvents such as dimethyl sulfoxide and glycerol was observed. This enzyme also exhibits stability under harsh environmental conditions and enantioselectivity towards naproxen and ibuprofen esters, yielding the medically relevant (S)-enantiomers. In conclusion, according to our knowledge, 499EST is the first thermoalkalostable esterase derived from a Gram-negative thermoacidophilic bacterium.
authors.affiliation: Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana, POB 56710, Bogotá, DC, Colombia.
authors.forename: Gina
authors.initials: G
authors.lastname: López
authors.forename: Jennifer
authors.initials: J
authors.lastname: Chow
authors.forename: Patrick
authors.initials: P
authors.lastname: Bongen
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lauinger
authors.forename: Jörg
authors.initials: J
authors.lastname: Pietruszka
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Streit
authors.forename: Sandra
authors.initials: S
authors.lastname: Baena
mesh_terms: D016947:Acetobacteraceae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D002712:Chlorides / Q000378:metabolism; D016000:Cluster Analysis; D003105:Colombia; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020536:Enzyme Activators / Q000378:metabolism; D004795:Enzyme Stability; D005290:Ferric Compounds / Q000378:metabolism; D045482:Hot Springs / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002712:Chlorides; D004269:DNA, Bacterial; D020536:Enzyme Activators; D005290:Ferric Compounds; D008049:Lipase; C024555:ferric chloride