Document Type


Publication Date


Publication Title

Applied and Environmental Microbiology


Thayer School of Engineering

Additional Department

Department of Biological Sciences


Low-G+C thermophilic obligate anaerobes in the class Clostridia are considered among the bacteria most resistant to genetic engineering due to the difficulty of introducing foreign DNA, thus limiting the ability to study and exploit their native hydrolytic and fermentative capabilities. Here, we report evidence of natural genetic competence in 13 Thermoanaerobacter and Thermoanaerobacterium strains previously believed to be difficult to transform or genetically recalcitrant.

In Thermoanaerobacterium saccharolyticum JW/SL-YS485, natural competence- mediated DNA incorporation occurs during the exponential growth phase with both replicating plasmid and homologous recombination-based integration, and circular or linear DNA. In T. saccharolyticum, disruptions of genes similar to comEA, comEC, and a type IV pilus (T4P) gene operon result in strains unable to incorporate further DNA, suggesting that natural competence occurs via a conserved Gram-positive mechanism. The relative ease of employing natural competence for gene transfer should foster genetic engineering in these industrially relevant organisms, and understanding the mechanisms underlying natural competence may be useful in increasing the applicability of genetic tools to difficult-to-transform organisms.



Original Citation

Shaw AJ, Hogsett DA, Lynd LR. Natural competence in Thermoanaerobacter and Thermoanaerobacterium species. Appl Environ Microbiol. 2010 Jul;76(14):4713-9. doi: 10.1128/AEM.00402-10. Epub 2010 May 14. PMID: 20472726; PMCID: PMC2901744.