Isolation and Characterization of a Halotolerant w-Transaminase from a Triassic Period Salt Mine and Its Application to Biocatalysis

We report the cloning and expression of an (S)-selective w-TAm from a Halomonas sp.(Ad2-TAm), isolated from an extreme hypersaline environment formed during the Triassic period (circa 220 mya).
Ad2-TAm exhibits an ability to convert a range of structurally diverse aldehyde and ketone substrates, with no decrease in conversion up to 1.5 M (8.8%) NaCl. The enzyme is also tolerant to the presence of organic cosolvents up to 30% and accepts a range of amino donors. These characteristics make Ad2-TAm a promising candidate for industrial applications, whilst also highlighting the value of extreme environments as a source of novel enzymes for the pharmaceutical industry as a whole.