Production of fine chemicals using thermophilic bacteria
In parallel to our research on biofuels, we have also pioneered studies on the production of branched-chain and long-chain alcohols (BCOHs and BCFAs) from amino acids by thermoanaerobes. Revising Orlygsson PhD work led to our discovery that branched-chain alcohols are a major fermentation product from branched-chain amino acids by thermophilic bacteria under very specific conditions. Electron scavenging is possible by either using thiosulfate as an electron sink or by growing the amino acid degrading thermophile in a co-culture with a hydrogenotrophic methanogen. We tried both alternatives and only in the presence of thiosulfate did we see a mixture of BCFAs and BCOHs being produced. During co-culturing with a methanoge, only the production of BCFAs was observed. We have now published this work in three articles (Scully et al., 2014; Scully & Orlygsson, 2014; Scully & Orlygsson, 2015) although the work is ongoing.
Further work on thermophilic bacteria has since then brought to our attention the ability of 1,2-propanediol (1,2-PD) production from deoxysugars by bacteria within the genus Caldicellulosiruptor. Earlier investigations reported this ability for only one species within this genus when grown on rhamnose. These findings were published in Anaerobe in 2017. Two other publications within this research scope will follow in 2018, one reporting the maximization of 1,2-PD production from the most promising Caldicellulosiruptor strains, and another reporting the production of 1,2-PD formation from macroalgae hydrolysates.
Jóhann Örlygsson, Professor, School of Business and Science, University of Akureyri, Iceland
- Ingvadottir EM, Scully SM, Orlygsson J. 2017. Evaluation of the genus Caldicellulosiruptor for the production of 1,2-propanediol from methylpentoses. Anaerobe, 47, 86-88.
- Scully SM, Iloranta P, Myllymaki P, Orlygsson J. 2015. Branched-chain alcohols formation by thermophilic bacteria within the genera of Thermoanaerobacter and Caldanaerobacter. Extremophiles. 19. 809-818.
- Sculy SM, Orlygsson J. 2015. Amino Acid Metabolism of Thermoanaerobacter Strain AK90: The Role of Electron-Scavenging Systems in End Product Formation. Journal of amino acids. http://dx.doi.org/10.1155/2015/410492
- Scully MS, Orlygsson J. 2014. Branched-chain alcohol formation from branched-chain amino acids by Thermoanaerobacter brockii and Thermoanaerobacter yonseiensis. Anaerobe, 30, 82-84.