Acetogenic bacteria and methanol
Acetogens are promising biocatalysts for the sustainable production of biocommodities from waste gas streams or biomass syngas as feedstock. Indeed their fermentation products, e.g., butanol, acetone, organic acids, are increasingly used for biofuels, clean beauty ingredients, etc. Furthermore, the whole contributes to reducing greenhouse gas emissions. Nevertheless, the fermentation of gas feedstock faces technical challenges resulting in poor microbial productivity. As a result, methanol -itself produced from syngas- has emerged as a substrate alternative to the direct use of C1 gases. Eubacterium limosum is one of the few acetogens that can utilize methanol and is genetically accessible. E. limosum is therefore a promising candidate for the recombinant production of biocommodities from this C1 carbon source. But, although several genetic tools are already available, brightly fluorescent reporting systems are still to be developed. They are indeed mandatory for mechanism deciphering and further metabolic engineering.
Results of M. Flaiz et al.
Published in Biotechnology for Biofuels 2021 by Maximilian Flaiz et al. The research group expanded the genetic toolbox of E. limosum by implementing FAST of The Twinkle Factory as a fluorescent reporter protein. They indeed constructed recombinant strains that expressed the gene encoding FAST in an inducible and constitutive manner. Cultivation of these recombinant strains resulted in brightly fluorescent cells even under anaerobic conditions. Moreover, they produced butanol and acetone from methanol with recombinant E. limosum strains. Therefore, the researchers used E. limosum cultures that produced FAST-tagged fusion proteins of the bifunctional acetaldehyde/alcohol dehydrogenase or the acetoacetate decarboxylase, respectively. They hence were able to monitor fluorescence intensity and product yields during growth. Moreover, their results show that FAST-tagged fusion proteins can be constructed without negatively impacting the stability, functionality, and productivity of the resulting enzyme.
- bioRxiv 2021 – Four species of bacteria deterministically form a stable biofilm in a millifluidic channel: assembly principles
- mBio 2020 – Interspecies Microbial Fusion and Large-Scale Exchange of Cytoplasmic Proteins and RNA in a Syntrophic Clostridium Coculture
- Appl. Environ. Microbiol. 2019 – A Strongly Fluorescing Anaerobic Reporter and Protein-Tagging System for Clostridium Organisms Based on the Fluorescence-Activating and Absorption-Shifting Tag Protein (FAST)
- Sci. Rep. 2018 – The inducible chemical-genetic fluorescent marker FAST outperforms classical fluorescent proteins in the quantitative reporting of bacterial biofilm dynamics
The Twinkle Factory sells the fluorogens for FAST and splitFAST. Stain different. Tag FAST.