A polyextremophilic alcohol dehydrogenase from the Atlantis II Deep Red Sea brine pool

Abstract

Enzymes originating from hostile environments offer exceptional stability under industrial conditions and are therefore highly in demand. Using single‐cell genome data, we identified the alcohol dehydrogenase (ADH) gene, adh/a1a, from the Atlantis II Deep Red Sea brine pool. ADH/A1a is highly active at elevated temperatures and high salt concentrations (optima at 70 °C and 4 mKCl) and withstands organic solvents. The polyextremophilic ADH/A1a exhibits a broad substrate scope including aliphatic and aromatic alcohols and is able to reduce cinnamyl‐methyl‐ketone and raspberry ketone in the reverse reaction, making it a possible candidate for the production of chiral compounds. Here, we report the affiliation of ADH/A1a to a rare enzyme family of microbial cinnamyl alcohol dehydrogenases and explain unique structural features for halo‐ and thermoadaptation.

Crystal Structure and Active Site Engineering of a Halophilic γ-Carbonic Anhydrase

“…Recent years have seen the discoveries of extremophiles in environments previously considered uninhabitable (Madigan and Marrs, 1997;Cavicchioli et al, 2011;Antunes et al, 2017;Jorquera et al, 2019;Merino et al, 2019). To date, enzymes from extremophiles gained increasing attention because they have adapted their structure and retained their function under harsh conditions, where their mesophilic homologs are non-functional (Persidis, 1998;Akal et al, 2019). In particular, these proteins are attractive for biotechnological and chemical industries keen on replacing traditional catalysts with enzymes.…”

Bioprospecting of Novel Extremozymes From Prokaryotes—The Advent of Culture-Independent Methods

“…Halophilic organisms and their enzymes are used in several different fields, including production of fermented foods, manufacturing of solar salt from seawater, leather industries, environmental bioremediation and textile, pharmaceutical ( Karan and Khare, 2010 ; Oren, 2010 ; Karan et al, 2012a ; de Lourdes Moreno et al, 2013 ; Akal et al, 2019 ). The biochemical properties of the molecules, enzymes, and compatible solutes synthesized by halophiles also present potential implications in fine chemicals, medicines, and bioimplants ( Irwin, 2010 ; Karan et al, 2012a , b ; Chen and Jiang, 2018 ; Jin et al, 2019 ).…”

“…Further advances allowed researchers to study the genome from single cells ( Grötzinger et al, 2014 , 2017 ; Akal et al, 2019 ; Karan et al, 2019 ; Vogler et al, 2020 ). Single amplified genome (SAG) technology separates individual cells before analyzing their DNA, thus giving us information about each cell’s genome instead of bulk metagenomes.…”

Uncommon overoxidative catalytic activity in a new halo‐tolerant alcohol dehydrogenase

“…[14] ADHs with greater stability towards polar organic solvents have been expressed from halophilic microorganisms [15] and from amplified genomes from unculturable species occurring in brine pool. [16,17] In this work, an ADH gene (HeADH-II) identified from the genome of Halomonas elongata was codon optimized and expressed in E. coli; Halomonas elongata is a halo-adapted bacterium which has been previously used as source of enzymes with remarkable solvent-tolerance and stability under operating conditions . [18][19][20][21] HeADH-II was characterized and used as biocatalyst, proving its ability to oxidize both primary alcohols and aldehydes, showing enhanced stability towards water-miscible co-solvents (e. g., DMSO).…”

“…New enzymes with improved solvent tolerance may be found in extremophiles [14] . ADHs with greater stability towards polar organic solvents have been expressed from halophilic microorganisms [15] and from amplified genomes from unculturable species occurring in brine pool [16,17] . In this work, an ADH gene (HeADH‐II) identified from the genome of Halomonas elongata was codon optimized and expressed in E. coli ; Halomonas elongata is a halo‐adapted bacterium which has been previously used as source of enzymes with remarkable solvent‐tolerance and stability under operating conditions .…”