Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023
Höfundar / Authors: Eva M. Ingvadóttir, Sean M. Scully
Starfsvettvangur / Affiliations: University of Akureyri, Faculty of Natural Resource Sciences
Kynnir / Presenter: Eva M. Ingvadóttir
Chirality – the „handedness“ of life – and its influence on living organisms has fueled the field of asymmetric synthesis. The search for biological agents capable of resolving racemic compounds has led to the characterization of robust catalysts including alcohol dehydrogenases (ADHs). Due to their high thermostability and solvent tolerance, ADHs from Thermoanaerobacter spp. have received particular attention since the 1980s, most notably T. pseudethanolicus. However, as most members of the genus remain unexplored in terms of their ADHs, a culture-based approach was undertaken to elucidate the ADH activities of the genus by substrate mapping. A handful of strains showed NADP+-dependent ADH activities on secondary alcohols similar to that of T. pseudethanolicus, with crude ADH extracts reaching activities of over 30 mU/mg protein. Secondary to primary ADH activity ratio (SADH/PADH) remained virtually unchanged for most members of the genus at temperatures below Topt. Notable exceptions included T. pseudethanolicus while T. italicus, T. pentosaceus, and T. siderophilus showed a higher activity ratio when cultivated at their Topt. Growth media supplementation with peptone and C2-4 alcohols resulted in multifold increase in ADH activities and overall better growth of T. brockii subsp. finnii, T. pseudethanolicus, and T. sulfurigignens whose whole-cells were used to catalyze oxidations and reductions of chiral secondary alcohols, diols and pro-chiral ketones respectively.