Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster V24

Amino Acid and Carboxylic Acid Metabolism of the genus of Thermoanaerobacter

Höfundar / Authors: Sean Michael Scully (1,2), Jóhann Örlygsson (1)

Starfsvettvangur / Affiliations: 1. University of Akureyri, 2. University of Iceland

Kynnir / Presenter: Sean Michael Scully

The protein and amino acid metabolism of thermophilic bacteria has been a neglected aspect of their physiology despite its biotechnological potential. Under anaerobic conditions, the metabolism of most amino acids requires an electron scavenger to effectively remove reducing equivalences and make the overall reaction thermodynamically favorable. Thermoanaerobacter and Caldanaerobacter strains cultivated on branched-chain amino acids (BCAAs) in the presence of a methanogen or thiosulfate yielded in the corresponding branched-chain fatty acid (BCFA) or a mixture including the BCFA and the corresponding branched-chain alcohol (BCOH), respectively. Thus, these electron scavenging systems reveal a difference in the electron flow resulting in different fermentation products. Studies involving the genus showed differences in amino acid utilization patterns and the degree to which strains are proteolytic, although the inherent ability to degrade BCAAs to their corresponding BCFA and BCOH appears to be a universal feature. Initially, the pathway responsible for BCOH formation was unclear; subsequent investigations using 13C-labeled BCAAs, as well as added fatty acids demonstrated that some strains could convert them to their corresponding alcohols. Subsequent work demonstrated that Thermoanaerobacter pseudethanolicus and Thermoanaerobacter strain AK85 are useful agents for the biotransformation of C2-C6 fatty acids to their corresponding alcohols in the presence of an electron donor.